BIOLOGICAL PROBLEMS IN
           WATER POLLUTION
              Third Seminar
                    1962
              Planned and Assembled
                      by
             Dr. Clarence M. Tarzwell
               Chief, Aquatic Biology
                 Research Branch

        Robert A. Taft Sanitary Engineering Center
U. S. DEPARTMENT OF HEALTH, EDUCATION, AND WELFARE
               Public Health Service
       Division of Water Supply and Pollution Control
                 Cincinnati, Ohio

                    1965

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   The ENVIRONMENTAL HEALTH SERIES of reports was established to report
the  results  of  scientific  and engineering studies of man's environment: The
community, whether urban, suburban, or rural, where he lives, works, and plays;
the air, water, and earth he uses and re-uses; and the wastes he produces and must
dispose  of in a way  that preserves these natural resources.  This SERIES of
reports provides for  professional users a central source of information on the
intramural research activities of Divisions  and Centers within the Public Health
Service,  and on their cooperative activities with State and local agencies, research
institutions, and industrial organizations. The general subject area of each report
is indicated by the two letters that appear in the publication number; the indicators
are

                  WP   -  Water Supply and Pollution Control

                  AP    -   Air Pollution

                  AH    -  Arctic Health

                  EE    -   Environmental Engineering

                  FP    -   Food Protection

                  OH    -   Occupational Health

                  RH    -   Radiological Health

   Triplicate tear-out abstract cards are provided with reports in the SERIES to
facilitate  information  retrieval.   Space is provided on the cards for the user's
accession number and key  words.

   Reports  in the  SERIES will be distributed  to requesters, as supplies permit.
Requests  should be directed to the  Division identified on the title page or to the
Publications Office, Robert A. Taft Sanitary Engineering Center, Cincinnati, Ohio
45226.
              Public Health Service Publication No. 999-WP-25

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                    SEMINAR COMMITTEE
DR. ALFRED F. BARTSCH
Chief, Enforcement Activities
Water Supply and Pollution
   Control Program
Pacific Northwest
THOMAS E. MALONEY
Biologist
Aquatic Biology Section
Research Branch, SEC
DR. WILLIAM M. INGRAM
Biologist
Field Operations Section
Technical Services Branch, SEC
EUGENE W. SURBER
Biologist
Aquatic Biology Section
Research Branch, SEC
DR. HERBERT W. JACKSON
Biologist
Water Supply and Pollution
   Control Training Activities
Training Program, SEC
DR. CLARENCE M. TARZWELL
Committee Chairman
Chief
Aquatic Biology Section
Research Branch, SEC
DR. C. MERVIN PALMER
Biologist
Aquatic Biology Section
Research Branch, SEC
CHANDLER C. WAGGONER
Administrative Assistant
Research Branch, SEC

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                                             FOREWORD
   The  Seminars  on Biological  Problems  in Water
Pollution were initiated in  1956  and have been con-
tinued because  it is believed they  meet a need in
the  young  but  growing  field of  sanitary  biology.

   The objectives of the seminars are:

1. To bring together those  engaged in biological re-
   search and investigations of water pollution prob-
   lems  so that they may become acquainted with
   each other.

2. To  learn  of  current developments in this field,
   research and investigations in progress, and the
   most recent findings and problems.

3. To  carry  on discussions  that  will indicate new
   approaches to old problems, define new problems,
   iron out disagreements as to approaches and basic
   philosophy, generate new ideas  and new perspec-
   tives, and  assist in the solution of common or
   troublesome problems.

4. To acquaint those in the field with new equipment,
   experimental procedures, and methods of handling,
   analyzing, and  evaluating data  so  that they may
   better approach the problem.

5. To enable those engaged in training future workers
   to learn first hand what those who  are presently
   engaged in the  field believe should be included in
   the curricula of training programs.

6. To broaden viewpoints, assist workers in compre-
   hending  the overall problem, and,  above all, to
   stimulate them and create a greater incentive and
   appreciation for their work and a keener under-
   standing of  their  role  in this public service.

   These seminars  have been set up as discussion
meetings with emphasis on participation by -those in
attendance. Sessions are a half day or a day in length
and  each deals with a particular subject.  Papers
for  each of the sessions are by invitation and each
paper  deals with a  particular phase of the subject,
which thus  is covered in the most adequate manner.
The  number  and  length  of papers  are limited to
provide ample time for discussion from the floor„

   In addition to the more formal seminar, informal
sessions on pertinent topics are  scheduled.  In these
informal sessions, only one paper is presented by the
discussion  leader; the rest of the session is devoted
to questions and a thorough discussion of the subject.
These  informal sessions  have  proven to be  very
popular and many believe they are the most important
part of the  seminar.

   Plans for  the third seminar  were begun shortly
after completion of  the second seminar in 1959. In
viewing items of current importance and interest, it
appeared that water supplies of adequate quality and
quantity  were or would  shortly be of  prime im-
portance.  It  soon became  evident that with a fixed
fresh water  supply  the best method  of  augmenting
this  supply was to use the same water over and over.
Such reuse, however, requires that each user return
the water  to  its  source in a  condition satisfactory
for another use.   To do this effectively and effi-
ciently, he must know the quality  of water required
for the desired use.  In the case of the production of
aquatic life, we must know the quality  of water re-
quired for the survival, growth, reproduction, general
well being, and the development of an adequate crop
of the  desired organisms.   In short, we  must have
water  quality  criteria for the protection  of aquatic
life.   It was judged, therefore,  that a seminar on
water  quality  criteria for aquatic  life would be both
timely and beneficial.  Such a seminar would serve
to assemble, present, and evaluate current informa-
tion  on the environmental  requirements  of aquatic
organisms, which would lead to sounder conclusions
on which  to base water quality  criteria for their
protection.   It was  hoped that the transactions of
such  a seminar would  serve, at  least initially, as
a  handbook in the field and a stimulus for further
work  essential for the setting of better  criteria.

   The seminar  was  timed  for the week preceding
the 14th meeting  of the International  Association of
Theoretical and  Applied Limnology  held in August
1962  at Madison, Wisconsin.  This enabled foreign
scientists to attend and contribute to both meetings.
In formulating the program for the third seminar, a
world-wide search was  made for people knowledge-
able in the environmental  requirements  of certain
organisms  or  groups of organisms.   That  this ef-
fort  was fruitful is attested by the roster of parti-
cipants.

   Those in attendance from outside the United States
numbered  88, in a  total registration  of 436,  and
represented 26 countries.  Canada led in the number
of delegates with  representatives from all the prov-
inces;  several other countries were well represented.
In the  United  States, 43 states and  the District of
Columbia were represented.  Universities contributed
the largest single group, with conservation agencies
ranking second.   Agencies and groups represented
were  the U.S. Public Health Service,  U.S. Fish and
Wildlife Service, U.S. Department of  Agriculture,
Tennessee  Valley Authority, Atomic Energy Com-
mission, Bureau of Reclamation,  Great Lakes Fish-
ery  Commission, Ohio  River Valley Water Sanita-
tion  Commission, Food and  Agriculture  Organiza-
tion,  National Wildlife Federation,  Sport  Fishing
Institute, Audubon Society, Conservation Foundation,
and  Federal,  State,   and  Provincial Conservation,
Health, and Water Pollution Control Agencies.

   The deliberations, presentations, and discussions
of this group  are presented in these transactions.
Every effort  has been  made  to  present all ideas
expressed during  the discussions in  both the formal
and informal sessions.  It is hoped that these trans-
actions will  prove of  real  value not only  to those
who  attended,  but to workers in the field  of water
pollution everywhere.

                      Clarence M. Tarzwell

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                              ACKNOWLEDGMENTS

    The  translations  of  the  abstracts  of  the papers  in these transactions into French and
German  have been made possible through the  kind  assistance of a number of people. Dr.
Paul Rothemund, Chemist, of the Aquatic Biology  Section, Basic and Applied Sciences Branch,
Division  of Water  Supply and Pollution Control of the United States Public Health Service at
the Robert A. Taft Sanitary Engineering Center translated the abstracts into German.  We are
indebted  to the  Fisheries Research Board  of  Canada through the efforts of Dr. John Sprague
of their laboratory at St.  Andrews, New Brunswick, for the translations into French of sixteen
abstracts,  including thirteen  by authors  from the United Kingdom.  Miss Maud Nisbet of the
Central Station  of  Applied Hydrobiology, Paris, France, kindly translated fifteen of the ab-
stracts into  French. -  We are  also  indebted to Mr. Robert J. Griffin, Jr., Administrative
Assistant  of Radiological Health Research Activities, Robert  A.  Taft Sanitary Engineering
Center, for  his assistance  in  the  preparation of drafts and proof reading of many of the
French translations.   Mr.  Griffin was also instrumental  in securing the services of Mr.
Alain  Guillerd of  Lyon,  France, who translated  the remainder of the abstracts into French.
                                           vi

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                                          CONTENTS


                                                                                            Page

THE ROLE OF THE AQUATIC BIOLOGIST IN THE FEDERAL WATER POLLUTION CONTROL
     PROGRAM — James M. Quigley	    1

VALUE AND USE OF WATER QUALITY CRITERIA - B. B. Berger, Chairman	    5

     The Value and Use of Water Quality Criteria in the Federal Enforcement Program — Murray Stein  5

     The Value and Use of Water Quality Criteria to Protect Aquatic Life in State Programs —
           M. P. Adams	    7

     The Value and Use of Water Quality Criteria to Protect Aquatic Life. A Rational Industrial
           Viewpoint - R. F. Weston	    9

     The Value and Use of Water Quality Criteria In Conservation Programs — T. L. Kimball	   12

     Discussion — C. M. Tarzwell	   14

ENVIRONMENTAL REQUIREMENTS OF PLANKTON ALGAE AND THEIR EFFECTS ON WATER
     QUALITY  - G. E. Fogg, Chairman	   19

     Diatoms and Their Physico-Chemical Environment — C. W. Reimer	   19

     The Application of Diatom Ecology to Water Pollution and Purification — F. E. Round	   29

     The Importance of Extracellular Products of Algae in the Aquatic Environment — G. E. Fogg ...   34

     Toxic Waterblooms of Blue-Green Algae — P. R. Gorham	   37

ENVIRONMENTAL REQUIREMENTS OF FRESH-WATER INVERTEBRATES -
     L. A.  Chambers, Chairman	   45

     Bacteria-Protozoa as Toxicological Indicators in Purifying Water — S. H.  Hutner, Herman Baker,
           S. Aronson, and A. C. Zahalsky	   45

     Environmental Requirements of Fresh-Water Protozoa — John Cairns, Jr	   48

     Relations of Planktonic Crustacea to Different Aspects of Pollution  - Jaroslav Hrbacek	   53

     The Biology  of the Tubificidae with Special Reference to Pollution — R. O. Brinkhurst	   57

ENVIRONMENTAL REQUIREMENTS OF MA.RINE INVERTEBRATES - M. R. Carriker, Chairman ...   67

     Bioassays of Pulp Mill Wastes With Oysters — C. E. Woelke	   67

     The Effect of Environmental Factors on Larval Development of Crabs — J. D. Costlow, Jr., and
           C. G. Bookhout	   77

     Environmental Requirements of Shrimp — A. C. Broad	   86

     Reaction of Estuarine Molluscs to Some Environmental Factors — P. A. Butler	   92

ENVIRONMENTAL REQUIREMENTS OF AQUATIC INSECTS - T. T. Macan, Chairman	  105

     Environmental Requirements of Plecoptera — A.  R. Gaufin	  105

     Environmental Requirements of Ephemeroptera — J. W. Leonard	  110

     Environmental Requirements of Trichoptera — S. S. Roback	  118

     A Survey of Environmental Requirements for the Midge (Diptera: Tendipedidae) — L. L. Curry  .  127

                                               vii

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     The Influence of Predation on the Composition of Fresh- Water Communities — T. T. Macan ....  141

ENVIRONMENTAL REQUIREMENTS OF FISHES AND WILDLIFE - F. T. K. Pentelow, Chairman
     (Fishes)  R. E.  Johnson, Chairman (Fishes and Wildlife)	  145

     Dissolved Oxygen Requirements of Fishes — Peter Doudoroff and C.  E. Warren	  145

     The Environmental Requirements of Centrarchids with Special Reference to Largemouth Bass,
           Smallmouth Bass, and Spotted Bass — G. W. Bennett	  156

     Water Quality Criteria for Fish Life - Marcel Huet	  160

     Toxicity of Some Herbicides, Insecticides, and Industrial Wastes — Paul Vivier and M. J. Nisbet.  167

     Tainting of Fish by Outboard Motor Exhaust Wastes as Related to Gas and Oil Consumption-
           E. W.  Surber, J. N. English, and G. N.  Me Dermott	  170

     Effects of Oil Pollution on Migratory Birds - R. C. Erickson	  177

     Factors That Affect the Tolerance of Fish to Heavy Metal Poisoning — Richard Lloyd	  181

     Salinity Requirements of the Fish Cyprinodon macularius — Otto Kinne	  187

THE CONCENTRATION OF RADIONUCLIDES IN AQUATIC ORGANISMS, THEIR PASSAGE THROUGH
     THE FOOD CHAIN, AND POSSIBLE EFFECTS - C. P.  Straub, Chairman	  195

     Radioactivity in Freshwater Organisms  of Some Lakes of Northern Italy —  Oscar Ravera	  195

     Accumulation of Radionuclides and the Effects of Radiation on Molluscs — T. J. Price	  202

     Accumulation of Radionuclides by Aquatic Insects — J. J.  Davis	  211

     Relationships Between the Concentration of Radionuclides in Columbia River Water and Fish —
           R. F. Foster and Dan McConnon	  216

                                  INFORMAL DISCUSSION SESSIONS

BIOLOGICAL INDICATORS OF POLLUTION -

     Algae as Indicators of Pollution — Ruth  Patrick	  225

     Some Remarks  on a New Saprobic System — E. F. Fjerdings^ad	  232

     The Significance of M,icro-Invertebrates in the Study of Mild River Pollution — H. B. N.  Hynes . .  235

ORGANIC PESTICIDES - THEIR DETECTION, MEASUREMENT AND TOXICITY TO  AQUATIC LIFE -
     O. B. Cope and  C. H. Hoffmann, Chairmen	  245

     Pesticide-Wildlife Relations — O. B. Cope	  245

     Effects of Time and Temperature on the Toxicity of Heptachlor and Kepone to  Redear Sunfish —
           W. R. Bridges	  247

     The Use of Carbon for Measuring Insecticides in Water Samples —
           C. C. VanValin and B. J. Kallman	  250

     How Should Agricultural Pollutants be Controlled? — C. H. Hoffman	  253

     Pesticide Pollution Studies in the Shoutheastern States — H. P. Nicholson	  260

THE RELATION OF LAND USE TO THE AQUATIC ENVIRONMENT - W. E. Bullard, Jr. and
     A. D. Harrison, Chairmen	  265
                                                viii

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      Role of Watershed Management in the Maintenance of Suitable Environments for Aquatic Life —
           W. E. Dullard, Jr	  265

      Some Environmental Effects of Coal and Gold Mining on the Aquatic Biota — A. D. Harrison ....  270

      The Effects of Stream Sedimentation on Trout Embryo Survival — J. C. Peters	  275

THE CONTROL OF FISH DISEASES AND PARASITES -  S. F. Snieszko, Chairman	281

      The Control of Bacterial and Virus Diseases of Fishes — S. F. Snieszko	  281

      The Control of Fish Parasites - G. L. Hoffman	  283

DETERMINATION OF THE CAUSE OF FISH KILLS - G. E. Burdick, Chairman	  289

      Some Problems in the Determination of the Cause of Fish Kills — G. E. Burdick	  289

      An Experimental Analysis of the  Factors Responsible for the Periodic Mortalities During Winter
           in Bushveld Dams in the Transvaal,  South Africa — B. R. Allanson, M, H. Ernst, and
           R. G. Noble	  293

THE ARTIFICIAL EUTROPHICATION OF OUR WATERS - E. A.  Thomas, Chairman	  299

      The Eutrophication of Lakes and  Rivers, Cause and Prevention — E. A. Thomas	  299

      The Biological Removal of Nitrogenous Compounds from Sewage Treatment Plant Effluents —
           W. M. Beck, Jr	  306

DETERMINATION OF SAFE LEVELS OF TOXICANTS AND OTHER POLLUTANTS IN THE AQUATIC
      ENVIRONMENT - L. L. Smith,  Jr., D. F. Alderdice, and C. G. Wilbur, Chairmen  	  309

      Apparatus for Bioassay of Wood Fibers with Fish Eggs and  Fry —
           L. L. Smith and Robert Kramer	  309

      The Design of a New Fish Respirometer — J. R. Brett	  312

      Apparatus Used for Studying Avoidance of  Pollutants by Young Atlantic Salmon — J. B. Sprague. .  315

      An Apparatus for Testing and Swimming Habits of Fishes — K. A. Pyefinch	  315

      Physiological Considerations in Studies of the Action of Pollutants on Aquatic Animals —
           P. O. Fromm	  316

      Analysis of Experimental Multivariable Environments Related to the Problem of Aquatic
           Pollution — D. F. Alderdice	  320

      The Biology of Water Toxicants in Sublethal Concentrations — C. G.  Wilber	  326

      Effects of Sublethal Concentrations of Zinc and Copper on Migration of Atlantic Salmon —
           J. B. Sprague	  332

      Effects of Cooling Water from Steam - Electric Power Plants on Stream  Biota - F. J. Trembley  334

      The Contribution of Bottom Muds to the Depletion of Oxygen in Rivers and Suggested Standards
           for Suspended Solids - P. C. G.  Isaac	  346

      Accumulation of Cesium-137 Through the Aquatic Food Web — R. C. Pendleton	  355

      Effects of Pollution on Oysters and Fish in Taiwan — Pao-Shu Chang	  368

SUMMARY  OF THIRD SEMINAR - C. H. Callison and R. H. Stroud	  371

ABSTRACTS	  377

                                                 ix

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                 THE ROLE OF THE AQUATIC BIOLOGIST IN THE FEDERAL

                         WATER POLLUTION CONTROL PROGRAM

                                            James M. Quigley *
   I  am  a  lawyer by profession,  a politician by
 nature, and an administrator by appointment.

   In the  light of this background,  one might very
 well  ask what  then  am I doing here  addressing a
 scientific seminar on the subject of  "Water Quality
 Criteria for Aquatic Life."   The answer rests with
 my third "qualification."  I am here, first, because
 I was appointed Assistant Secretary of  Health, Edu-
 cation, and Welfare by President Kennedy, and second,
 because  I was appointed by the Secretary of Health,
 Education, and Welfare to oversee the administration
 of our Department's Water Pollution Control Program.

   To those of you who at this moment are  experiencing
 an  instinctive reaction something along the line of,
 "Why would anybody  put a lawyer and a politician
 in charge of a Water  Pollution Control Program?",
 all I  ask is that you reserve final judgment until you
 hear  me through.  I  ask this because I believe that,
 whether  they  realized it or not and whether you know
 it or not, the people who made such an appointment
 had you in mind when they made it.

   Not you,  as individuals. Not you, as aquatic  biolo-
 gists. But rather, you, as representatives  of many
 individuals and many groups who have long had a deep
 and abiding interest in the ever-growing problem of
 water pollution in this country, and  who have often
 experienced frustration in your efforts to make a more
 substantial  contribution towards a  solution of this
 national problem.

   The aquatic biologist has a contribution to make to
 the solution of the water pollution problems of this
 country.   If I tell you that I conceive it as one of my
 prime duties  to see to it that aquatic biologists are
 given a greater opportunity to make such a contribution,
 you may just  begin to appreciate why it was that this
 lawyer  and politician was given the  administrative
 assignment  that has brought me here this morning.

   For too  long, problems of water pollution in this
 country have  been approached  in much  too  narrow,
 much too parochial ways. In a less complex society
 than we  now  live  in  the matter of water pollution
 invariably  became a community issue only when it
 became a health hazard.  Only when water made people
 sick did it become a matter of serious public concern.
 Nature has  been abundantly generous to our America
 and,  as  a result,  in  the past  in most  areas  of our
 country, when the  fish stopped  biting or the  water
 tasted a  little unpleasant, there was always plenty of
 other water to  fish  in  or swim in or drink.  Only
 when their lives or health were endangered were people
 ready  to  demand  and support government action to
 abate  pollution.    Such  government action usually
involved  the  local Board  of  Health.    Thus, the
traditional pattern was established  whereby water
pollution was viewed as merely a local healthproblem,
one that could and should be handled locally by doctors.
Initially this may have been an accurate appraisal of
the problem and under the circumstances more than
often may have provided an adequate solution. Unfortu-
nately, in many areas of the country, as our population
exploded, our cities grew, our industries expanded,
water pollution problems became something other than
just a local and just a healthproblem. Even more un-
fortunate  is that even to this  day the realization of
this development seems to have escaped the grasp of
too many public health officials.

   You  in this audience know better than anyone else
that  water that  may  be fit  to  drink  in the sense
that it will not perceptibly harm  human health may
in fact  be water that will not sustain fish life.  In the
traditional view of the public health doctor, this water
would not be polluted. In your view as modern aquatic
biologists, it surely is.
   But I would be in error and unfair if I were  to give
the impression that all of the  unsolved  problems in
the field  of water pollution control should be laid
on the door step of shortsighted public health doctors.
While doctors may have been the dominant force, they
have not and are not the only people involved in water
pollution matters.

   Engineers  have been part of the water pollution
picture for many  years.   Many of the  long-proven
effective sewage disposal techniques are the handiwork
and the brainchild  of sanitary  engineers.   For this,
we  can be and are grateful. But as one looks at the
current state of the art  of water pollution control
one cannot help feel that too often sanitary engineers
have  been content to stay with proven old ways, to
follow the beaten path.  The boldness and imagination
that  have characterized engineering efforts in such
varied fields as rocketry and saline-water conversion
have  all too often been lacking in their  approach to
water pollution control.
   In  my  judgment, we  have reached the point where
we  can no longer  afford halfway measures, when we
can no longer be satisfied with old-fashioned remedies
however wonderful they were in grandfather's day. The
nature and the scope and the volume of water pollution
today is such that it challenges  the engineering genius
of our nation.  There is need for extensive engineering
research  in this area.  But it should not involve the
mere expenditure  of more money, which does  little
more than refine and expand what we already have.
There is  a need to seek new ways, for bold men who
will venture down new paths, for  engineers who will
approach this problem with a willingness to experiment
with the unorthodox.
* Assistant Secretary, Department of Health, Education, and Welfare, Washington, D.C

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       ROLE OF AQUATIC BIOLOGIST IN THE FEDERAL WATER POLLUTION CONTROL PROGRAM
   But effective water  pollution control is no longer
just a health problem or just an engineering problem.
The  doctors  and the engineers can't  give us many
of the  answers  we need; they must be found in the
laboratory  — in the  chemistry laboratory, in the
biology laboratory.

   This is so because the aims of pollution abatement
in  today's  complex society  are at  least  sixfold:

   (1) To provide safe, palatable water of the quality
       desirable for  domestic uses;

   (2) to maintain and provide water supplies that are
       safe for agricultural uses such as stock watering
       and irrigation;

   (3) to maintain water supplies of the desired quality
       for  various  industrial processes  and  uses;

   (4) to  restore or maintain  safe waters that are
       pleasing  in  appearance  and free from un-
       desirable odors  for recreational uses such as
       swimming, boating, and skiing;

   (5) to provide water of the quality needed for sur-
       vival, growth, reproduction,  and the  general
       well-being of fresh-water, estuarial, and marine
       life;

   (6) to provide water suitable for power  generation
       and navigation.

   It will be seen that most of these have to do with the
providing of conditions suitable for living things, plants
and animals, and are thus biological in nature and the
concern of biologists.  As we delve  more deeply into
the detection of low levels of water pollution and the
effects of various pollutants, we find more and more
problems that fall within the general field of aquatic
biology, the science of aquatic life.

   It is in the field of ecology that the aquatic biologist
may make some of his  most important contributions.
In environmental sanitation an ecological concept and
an understanding of the environmental factors are of
great importance. In complex problems of this type it
is essential to work with nature and devise remedial
measures that fit into the natural scheme —  to work
with natural  laws rather than against them.  Putting
into  operation procedures opposed to natural processes
is a costly, wasteful, and senseless procedure that is
certain to result in failure in the long run.  All  life and
life  processes are  influenced  by the environment,
and  when it is changed through the addition of wastes
or some other means, a whole series of events may be
set in motion that may have important consequences
unforeseen by those alien to the life sciences. One role
of the aquatic biologist  is to point out environmental
relationships  and  the importance of a favorable en-
vironment for all forms of life including man.

   We need general recognition of the fact that the
surest way to destroy  an animal or a species is to
destroy its environment or alter it so  that it is more
favorable  for other  organisms.  It is  not necessary
to have a directly  lethal agent  or actually to kill
members of a species in order to eliminate it.  Modi-
fications  of  the  environment  that render  it  less
favorable for the species in question but more favorable
for its competitors,parasites, diseases, andpredators
can eliminate that species  just as surely as a lethal
agent, even though elimination will occur more slowly.
Frogs cannot be raised in  a clover field, trout in an
eroded arroyo,  or bass in  a cesspool.   Neither can
trout be produced naturally in a stream where dissolved
oxygen or temperature  levels become lethal,  even
though such levels occur only one day of the year.  The
aquatic biologist can be  of value through continually
stressing the fact that the   average of environmental
conditions is not a measure of the suitability of an
environment  and that it is  the  extremes of environ-
mental conditions that are important and are the true
measure.


   In  addition to providing  an environmental concept
and supplying ecological information, the aquatic biolo-
gist can make other valuable contributions in the fields
of  water  supply,  waste treatment,  and pollution
abatement.  In these fields  he  can  serve not only in
research but also in field surveys and investigations;
technical services;  the  collection, recording,  and
evaluation of basic data; and in abatement investi-
gations and enforcement actions.

    The mention  of  enforcement actions  brings me
around to my fellow  lawyers.  If I seem disposed to
blame our doctor friends and our engineering friends
for not  having  accomplished more than we have in
water pollution abatement, how can I exonerate my own
profession? In the final analysis enforcement actions
are the very heart of any effective water pollution
control program.  Enforcement actions are basically a
legal   proceeding,  always  involving  lawyers   and
sometimes the courts.

   As  many  a  polluter  and many a  public  health
official has discovered, a clever  lawyer can undo in
very   short order months  and years   of scientific
investigation and research.  And I would caution you to
always keep  this in mind.   Your work in the field of
water pollution control is not likely to be very effective
if what you accomplish remains meaningful only to your
fellow  aquatic  biologist.  Unless you  can succeed
in translating the fruits of your labor into something
meaningful and important to enforcement officials —
be  they doctors, engineers, or lawyers  — you are
destined  to  remain  frustrated in your efforts  to
contribute to  the solution  of America's water pollution
problems. Your water quality criteria may indeed be
impressive in a  scientific journal, but  how will they
sound  to  a judge, and how will they stand up under
cross-examination in open  court?  You may be great
in the laboratory but completely ineffectual in a court-
room. If this is the case, how really successful will you
be in your efforts to help solve our pollution problems ?

   These  may be things they never taught you in gradu-
ate or undergraduate  school, but these are abilities you
must  acquire  if you are to make the full contribution
that will be demanded of aquatic biologists in the water
pollution abatement programs of the  future.

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        ROLE OF AQUATIC BIOLOGIST IN THE FEDERAL WATER POLLUTION CONTROL PROGRAM
   Finally, in order to be consistent, I suppose I should
say a few words about politicians. Like everybody else
the politician's record in this area is somewhat spotty.
Politicians, too, have not always advanced the cause of
water pollution control with speed and consistency. It
is a matter of record that elected public officials have
been known to put budgetary considerations ahead of
pollution abatement on more than a few occasions.
Many a politician whose public record of  support of
effective water pollution control programs is beyond
question has, I am sure, had moments of doubt when he
found these programs being vigorously enforced in his
own back yard.  As a former member of  Congress,
I can say that I fully appreciate the mixed emotions
involved when a big polluter also happens to be one of
your biggest supporters.

   But despite any such moments of doubt the record
is clear that in recent years the politicians who make
up our Federal Congress  have been far  ahead of the
doctors, the lawyers, the engineers, or the scientists
when it comes to water pollution control.

   To  its credit, the Congress of  the United States
clearly recognized  that water pollution problems are
not just local programs and that the Federal government
has a responsibility to help the local community meet
these problems.

   To  its credit, the Congress of  the United States
clearly recognized  that water pollution problems are
not just health problems, but involve broad challenges
that  have  economic, industrial, recreational,  and
aesthetic ramifications.

   To  its credit, the Congress of  the United States
recognized that the  engineers  and  the scientists not
only do not have all the answers to our water pollution
control problems, but they need help and encourage-
ment  to find  new answers.   This  help  and this en-
couragement  are inherent in the research provisions
that Congress wrote  into our Federal Water Pollution
Control Law.

   In water pollution control matters, in many respects
the record of the politician, at least those politicians
who  make up  our Federal government, is  the most
impressive  of all.  In my judgment, the politicians
have  now given  the  doctors and  the  lawyers,  the
engineers and the scientists the basic tools with which
to do the jobo  And what is that job?  To bring to an
end  the  wasteful  squandering of this nation's most
precious national resource — water. To accomplish
this  end is  the basic purpose of the Federal Water
Pollution Control Program.

   You as aquatic biologists have an essential role to
play in that program for, without the knowledge and
information  that men of your background and training
can alone provide, the program can never be a complete
success.  In the  art of pollution control, many of the
refinements that  must  come about if we are to meet
our national  needs for water can only be contributed
by men of your discipline.

   As  the man charged  with the responsibility for
making the Federal Water Pollution Control Program
work, I say to you that — within proper context —
there is  no  limit to the role the aquatic biologist can
play in this essential national program.  Why do I say
"within proper context"?   Because none of us  can
ignore the realities of life. And some of the realities
of life that all of us must be prepared to live with in
connection with the Federal Water Pollution Control
Program are such facts as:  There is never enough
money to do everything  you would like  to do. Our
program and your part in that program are in constant
competition  with  numerous other worthwhile efforts.
The  decision-making  process  in the bureaucracy
is often frustratingly long.  Sometimes these decisions
are,  from your point of view, made the  wrong way.

   In essence,  what I have to say to you is this. The
aquatic biologists have not suddenly inherited the earth.
In other words, you as aquatic biologists are not about
to dominate water pollution matters in the way doctors
or  again sanitary  engineers may have tended  to
dominate such programs in the past. Instead, you are
now  a recognized member of the team.  As the coach
of that team I would say, in all frankness, whether you
prove to  be a star or a bench warmer is entirely up to
you.

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                       VALUE AND USE OF WATER QUALITY CRITERIA

                                        B. B. Berger, Chairman *

    THE VALUE AND USE OF WATER QUALITY CRITERIA IN THE FEDERAL ENFORCEMENT PROGRAM.
                                           PANEL DISCUSSION
                                              Murray Stein t
   Mr. Chairman,  distinguished panel members, and
 friends, for the purposes of  those  who came late
 and  for certain other purposes,  I am going to use
 Mr. Berger's invitation letter as a point of departure.
 Here is what he said:  "The presentations should be
 deliberately provocative  to  elicit  a maximum  of
 response from  the floor.  In other words we want the
 public agencies, industry, and conservationists to lay
 their  opinions  right  'on the line'."  Mr. Berger put
 quotation marks around  "on the line." I guess that
 was to  indicate that a  man of his deep, scientific
 erudition and  broad  international interest and re-
 sponsibilities knew the  vernacular when he talked,
 but he wasn't quite sure about the panelists. Well,
 I  think  that any one of  these  panelists  knew that I
 would have done  it  anyway,  and as  for  the other
 members I think they would, too.  But, speaking for
 myself,  I appreciate the  fact that you've legalized it
 and  I have an invitation and I'm not indulging a policy
 of my own.  Here  are the three questions that were
 asked: (1) Are water quality criteria for the protection
 of aquatic  life  needed for effective water pollution
 control operations?  (2)  How can they best be used?
 (3)  What problems need to be solved before we can
 use water quality criteria for the protection of aquatic
 life?
   If we examine these questions, we see that the second
 and  third  assume that the development  of water
 quality criteria is necessary  and desirable.   It  is
 quite easy  to  say  that  water  quality criteria are
 necessary and desirable, but criteria  may be one  of
 those  double words.  We are not quite sure what it
 means, but I think when we  deal with it we have  to
 differentiate between criteria.   Obviously, whether
 you're a doctor, accountant, engineer, aquatic biolo-
 gist,  chemist, or physicist, when  you  come up  with
 an opinion or make a judgment, you are using profes-
 sional criteria.  There is, however, another type  of
 criteria  that some  of  us may  be   talking  about:
 criteria  developed  by a formal process of meetings,
 discussions, and chewing  the cud over and over again.
 I don't think we can establish the difference between
 these  two types of  criteria  by  saying that when a
 professional makes a judgment or when an engineer
 designs a water treatment plant  or a sewage treatment
 plant he is  classifying and using criteria, or when a
 lawyer makes a judgment in court,  he is using profes-
 sional criteria.  This is not  the  same as a group of
 people getting together in a formal process trying to
 get a consensus and coming up with criteria.

   I don't know what your predilections or your back-
 ground are—whether you prefer the preacher or the
football coach. We do have to get back to fundamentals,
however, before we can really begin to understand the
problem or its implications when we begin discussing
water quality criteria.

   When I went to  high school and college I was some-
what of an amateur biologist and I have always thought
of biology as essentially a descriptive science. There
are some  people who might try to get away from that
tendency,   but  I think that historically is where the
strength of biology  is  and  that is where the great
developments have come forth. Great things came from
discussions—whether it was Darwin describing what he
saw  in the Beagle,  or Morgan describing what he
saw  in  fruit  flies, or Mendel describing what he saw
in an Austrian pea garden.  Certain great advances in
our age have produced both truth and fads. Sometimes
these fads have  not truly  fit in with biology.  The
truth of our  age in  a large measure, someone said,
is a statistical truth. It is said that the characteristic
of our age is a slide.  That may be  what one of the
characteristic truths is—a  statistical truth.  If you can
count something, if you can put it down, people are very
much impressed. In  very very many places statistical
truth has  shown it is a remarkable tool in scientific
methods.   For example, you can take out by mathe-
matical processes the top  half of a planet, point a
telescope,  and there  it will be.   As you know, new
planets  have been  discovered that way.
   The  question whether we can apply this notion of
statistical  truth and reduce a science such as biology
to a  series  of statistical  truths  needs some real
profound thought.    I  am not sure it can be done in
many cases.   In one case, for example, I was called
by one  of  the United States Senators who  thought that
the biologist looking for statistical truth  in research
problems   was carried a  little  too  far.  Research
projects seem to catch on to the extent that they present
something  you  can count.  The  Senator  saiJ:  "I
understand the government has approved  a project to
investigate the rectal temperature of the hibernating
bear."  I  countered by asking how they  managed to
arrange for  the  experiment.   I never  did find out
whether the story was  true, but this  is  the end that
we  sometimes  get pushed  to  when we're  dealing
with statistical truths.
   The  other  kind  of  advance of  truths  involves
a bureaucratic truth or the group opinion or consensus.
This has certain advantages in that it fits in with our
society  as the statistical truth does, but  it has a few
differences.   It may fit in with the  democratic way
of life because of the consensus,  but there is a big
* Asst. Chief for Research, Div. of Water Supply and Pollution Control, Public Health Service, Washington, D.C.
•)• Chief, Enforcement Branch, Div. of Water Supply and Pollution Control, Public Health Service, Washington, D.C.

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                            VALUE AND USE OF WATER QUALITY CRITERIA
difference.  The group decision does not make a man
president when he gets 51 percent of the  votes, as
our Democratic party has done, nor does a farm bill
fail  because  of a  lack of a dozen  votes; neither
does it give  a minority a reasonable time to express
a point of view and go ahead. This isn't what happens
in the bureaucratic approach. I am speaking not only
of government  but of big industry  and universities
because  I  think by and large all of us—scientists,
aquatic biologists,  lawyers, and others—tend more
and more to work for these organizations.  What we
must arrive at is a group consensus whereby everyone
will  agree.   This may be  fine and this may lead to
the development of  criteria  or it may lead to a
formal document, but the relationship between what
comes out of this committee approach and getting
everyone to  agree and  establish a scientific truth,
is, I submit, sometimes peripheral.
   Some  people in charge of organizations like to go
to meetings and reach out to arrive at this consensus
of opinion.    This is a wonderful operation, but the
development of criteria in itself does not cleanup any
pollution.   Criteria  take  a long time  to develop
because we are not dealing with a specific  situation
but are taking in the -whole world and dealing with all
sorts of hypothetical situations.   There are really
no real social risks involved because we are waiting
for  a  complete  consensus,  or almost  complete
consensus, before we come out with any thing positive;
no one is going to be irritated. At the present time,
as some of you may know, Dr. McCallumis in Europe
and I am Acting Chief of the Division, and  I find it is
very easy  for  a person who  is  in charge of an
organization  to enlist recruits with  a  scientific
background so he can go forth with the full panoply
of experts to these meetings.   To some  people
this  is attractive.   I  have been  to  many of these
meetings myself, having spent over 20 years in the
Government.  I grew up and took my apprenticeship
going to these meetings.  It is something  like that
great American comedian.  Fred Allen used to say:
"Pull up a flea chair and sit down."  You have oppor-
tunity for advancement, which a man with a  scientific
background does have.   He can have the pleasure of
associating  with the top brass of his organization.
He can have an unending production of papers; they
may be shop  papers  or  cut doilies, but they will be
papers.  And he may also receive a lot of recognition
by mutual admiration societies, euphemistically called
professional  organizations,  if he wants to  engage in
that kind of practice.  Each committee will be another
line  to add  to his thumbnail  biography.   Now, this
is not  to say that life isn't tough within this frame,
because within it life is real and life is earnest and
careers are  made or broken.  As a matter of fact a
complete transformation takes place when the person
engaging in this can't recognize any tempest outside
of a teapot. These people spend their lives in mental
gymnastics.  I do not say they are not  creating a useful
social school, because this  has to be  done. We will
always find people  who will want to do this, and it is
good in  our  society.   What we have to consider is,
however, the other men, the men who want to achieve
in a scientific manner.

   There are  several problems we  know we have in
biology.   This science  is different from the other
sciences  and  it  is  not as easy perhaps to develop
criteria in this field as  in other fields.  For instance,
biology is a life science. The chemist and physicist can
reasonably know what happens here or in another world
or in another galaxy or predicament. The biologists
are not quite sure whether life is not a unique panacea.
Whatever your feelings  about the deeper mysteries of
life—whether spiritual or  mechanical—we do know that
a  live force  that has  a will of its own and moves
on its own in an unpredictable manner creates com-
plexities that are different in a measurable degree than
those of some of the other sciences. We do know that
you in the biological sciences, in  aquatic biology in
particular, are dealing with a complex ecology; you
know how complex it is, and the introduction of outside
elements  creates something that is  ever changing. We
know,  for example, that  use of  DDT affects the fly
and that the change in a single week in an interrelated
living process  can make tremendous changes in a com-
plete environment, often  in unpredictable ways. We
are seeing in the newspapers what a lot of us knew in
the past about the unexpected side effects caused by
the introduction  of new drugs or  chemicals into an
environment.

   These  are the things we are aware of in the biolo-
gical sciences. Sometimes it isn't  easy to transform
them into a statistical  formulation.  The mission of
the aquatic biologist in  the water pollution  control
field  is to leave us with water a little bit cleaner, or
to leave us with a little more knowledge. At the present
time  his  challenge in dealing with a life science and
a  descriptive  science  is to describe the effects of
pollution  and  the  causal relationship  between the
elements  that  create these effects, on a case-by-case
basis, with the  objective of abating or preventing
pollution.   The  compiling  of water  quality criteria
will follow. Aquatic biologists have atwofold mission:
First, they are protectors—the first line protectors—
of a vital natural resource, the biota of our streams;
second, they  can use  the  aquatic life as indicator
organisms  in  order  to   specify  fairly  detailed
pollution control measures and damages.  Throughout
the country one of the  big  problems we have now is
a proliferation of municipal and industrial waste treat-
ment plants  that may  be  adequately  designed, but
do not work effectively 365 days a year. If our electric
utilities do not have enough capacity and fall apart on
a winter  day, we hear about it soon enough; however,
when a water pollution control plant fails or doesn't
work for  a few days, we do not always know about it.
How  to determine whether a plant of this nature is
operating effectively all the time is a challenge for
the aquatic biologist. I think he has enough technical
know how  and   knowledge  to make  a judgment about
whether  a particular aquatic  environment is being
injured below a point of discharge, or what the situation
would be without that point of discharge.

   I am not against the development of criteria. What
I am  suggesting, though, is that we  guard against
allowing the development of criteria to be the main
force of our professional life.  Too  often an organi-
zation's   time,   budget,  and  staff  are completely
occupied  in developing water quality criteria while
they neglect the  job they  are created for, which is to
protect the quality  of  our waters.   One example,

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                                             State Programs
a  fish  kill,  is  rather  dramatic.   I am not even
dealing with  the  more  discreet  effects  on fish.
Time  after  time  I have  heard aquatic biologists
complain that they were not notified  in time,  that they
could not  get  to the fish kill, and that they did not
know what  caused it.  But I have not heard of  a motion
at any meeting to  set up a technique or methodology
or something that  would  bring biologists right to the
spot after  the fish kill on a case-by-case basis. We
could get  information.   The  point I  am making is
that  first  things  come  first.   There  is  no doubt
that  criteria are very important, but  let's not forget
that  we have to get the basic building blocks in shape
before we move them forward. I believe, too, that the
people who have participated  with us in an active
program to clean up pollution—that is, those who get
out on the firing line in  the field on a case-by-case
basis,  get into the stream, see what is happening,
make their report, stand up before God and country,
if  necessary, certainly before a  hearing board or in
the courts—have  found it stimulating. They have found
great satisfaction in it; they have found that by getting
out into  the  field and being closely questioned they
have  come up with  new insights for research and
presentation.   As  one person in the room told me
while preparing for a case: "You know, it is quite a
different thing preparing my presentation for a case
where I'm going to be cross-examined and one going
before a scientific society."   I think you should try
possibly to give yourself, if you have the courage, the
pleasure of going through with them and seeing what
that does to you and how it sharpens up your thinking.
I think that participation in an active program leads to
new concepts and this inevitably will develop criteria
with force and meaning. Too often have I seen criteria
developed  among  opposing   sides  and  some  high
administrator whose  major art is bringing together
differences or splits.  This may be the way to develop
a  good  social instinct, but whether this is the way
to arrive at scientific truth, I leave to you.
   I am  suggesting to the biologist and to the aquatic
biologist  in  particular  that  we need  your help in
cleaning up this  nation's polluted waters.   In every
enforcement   case we  have  had under  the Federal
program, effect on fish life was a problem for which
we needed the help of a biologist. I am suggesting that
in the process of cleaning up pollution and developing
comprehensive programs we can more readily arrive
at scientific  truth than we ever can in a meeting with
representatives from scientific societies, and govern-
mental organizations, and industries,  no matter how
exalted they may be.
 THE VALUE AND USE OF WATER QUALITY CRITERIA TO PROTECT AQUATIC LIFE IN STATE PROGRAMS

                                             Milton P. Adams *
   My connection with state water pollution control
efforts, as most of you know, is based for the most
part  in Michigan.   That period  of service  extended
from October 1, 1930, to July 1, 1962, on which date
I retired from state service.   Notwithstanding that
change of status, both Clarence Tarzwell and my suc-
cessor at Lansing, Larry Oeming, felt I should make
this  presentation.   So  here  I am, accompanied by
one  of your active co-workers—an exceedingly  in-
dustrious biologist and highly  prized member of our
staff—Carlos Fetterolf.

   State laws, parameters,  tests, standards, and re-
strictions changed  considerably  during my period of
service.  Many are of the opinion that despite progress
made to  bring present and  past waste and  pollution
under control, a losing  battle  has been waged by the
states.   This  accounts for recent strengthening of
Federal pollution legislation (Public Law 87-88) and
for action taken under this authority.

   It appears from a review of the transactions of
your  1956 and 1959 seminars that the subject before
this  panel is not a new one.  I really think you biolo-
gists already know the answers. You're waiting to see
if  we   make  a  mistake—a  federal  man, a state
administrator, a spokesman for industry, and  one for
wildlife.   Several  interests  seem to  be  omitted,
however,  from the ranks of the panelists and in the
restrictive  title  of  this program.   Water  quality
criteria is a subject for discussion here only as it
relates to the protection of  aquatic life. Perhaps it
is  to be assumed, or -can be shown later, that if aquatic
life is protected then all other uses such as  agriculture,
recreation, public health, and the like, will be cared
for as well.   For many years, I tangled with an in-
dustrial lobbyist  at  Lansing who always asked me
"What's more  important—payrolls  or fish?"   My
answer was always the same: "We have to have both."
   Chairman Berger requested each panelist in his
presentation to  consider three  questions. In answer
to the first one, "Are water  quality criteria for the
protection  of aquatic life needed  for effective water
pollution control operation," my answer would be either
"Yes and  no"  or "Yes, with certain reservations."
These I would now discuss.
 Former Executive Secretary, Michigan Water Resources Commission, Lansing, Michigan.

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                            VALUE AND USE OF WATER QUALITY CRITERIA
   As previously stated,  I dislike to see the criteria
under  discussion limited to the protection of aqua-
tic life only.  This throws the state administrator off
balance  at  the  outset.  If  he  needs criteris for the
protection of  aquatic life, he needs them equally for
the protection of other lawful  uses of the waters of
his state.  Across this broad  land  of ours differing
views  are held  by administrators  about the value
of standards, objectives, criteria, parameters, and the
like.  Some of these differences arise as the result of
contrasting  laws  or  public policy  with respect to
wastes and pollution within the 50 jurisdictions; others
are due  to the scarcity or inadequacy of background
information.

   None  of  the  states have had the resources for
conducting surveys, background studies,  planning, and
future projections that  are available, for instance,
to the Surgeon  General in the Great Lakes-Illinois
River  Basin  project or to the Secretary of  Health,
Education, and Welfare as he lays a future enforcement
foundation for correcting such ills and shortcomings as
exist in  the protection of the Detroit River and Lake
Erie.

   Most   state  adminstrators   necessarily  regard
criteria,  or  objectives,  or standards  as means of
facilitating  compliance  with  their  state  laws.  In
Michigan, for  instance, our law is  almost silent on
advance  planning but forthright in declaring what is
unlawful. Discharged substances injurious to the public
health, and the  conduct of any  industrial  enterprise
or other  lawful occupation that results in discharges
that destroy or prevent the  growth or propagation of
any fish, migratory bird life, wild animal, or aquatic
life are  all specifically mentioned—even the value of
lawfully  taken fish or game, impaired as the conse-
quence of pollution, are included. You will immediately
recognize an  opportunity  for   development  of   such
criteria  and  parameters as  MPN's, DO's,  BOD's,
pH's, phenols, cresols, oils and greases, cyanides,
chromium, and the like.

   On the assumption that all surface water  supplies
for public use must be filtered and chlorinated, we may
also encounter  1,000 MPN or  less  for acceptable
bathing beaches, and 5,000 MPN or more for sources of
public water supply.

   It is  significant, I think, that in the enactment of
state laws with  their varied prohibitions or  lack of
them, such things as water quality criteria are avoided.
Maybe this is because  few legislator sunder stand what
a  zero,  2,  or  5 ppm DO in  a natural water would
mean, or a  million  coliform  index.  Looking back
over my 32 years in Lansing, during which I served
six State Health  Commissioners, I have been aware of
widely varying concepts of what water qualities would
prove  injurious  to the  public  health!  And we still
lack a solid definition.

   While we,  as  administrators, and our  supporting
cadre  must have water  quality criteria as target
objectives in our work, however they may be expressed,
we would be less than realistic if we failed to recognize
their limitations as well as advantages when it comes
to solving a given problem.
   In the  early thirties, the degradation suffered by
the prize  coon dog of Jackson County after swimming
across Grand River below Jackson, as related by his
master before the visiting Circuit Judge, won a court
decision for a lower riparian plaintiff. My explanation
of charts  made  after an  exhaustive pollution survey
by my staff depicting the  rise and fall of DO and BOD
elicited from Judge Parker only the words "DO, BOD,
B  coli—Bah!"  You will  understand then  why in the
midst of their technical survey work I have dropped
the  suggestion to our boys "be on the  lookout for a
convincing lay witness—remember  the coon  dog."

   The Commission is  being  given a very hard time
right now in  an  extended paper mill hearing.  This
grew out   of  staff  and Commission adoption of a
minimum  DO criterion for the central section of the
Kalamazoo  River.   It  makes  no  difference that the
other eight managements in the valley have stipulated
and agreed to reduce their present waste contributions
to equal  39 percent of  the 1950 contribution of each.
Pro  rata  method accepted all around would provide
2.5 ppm DO when the river is at its 10-year frequency
of low  flow.  The staff  and Commission have had
to take  account  of  the  particularly severe condition
of stream use imposed by the concentration of pulp
and  paper mill production.  It cannot "give ground"
on the target objective of the remaining mill without
reopening the case  of all others.   So it's clear that
official  and  extended  proceedings  under our law
grounded  on the  application of water quality criteria
have failed, so far at  least, to bring results in the
central Kalamazoo River section.


   Finally, a third example might be mentioned where
objectives set after careful  studies have failed to
correct boundary water pollution between the United
States and Canada.  I hasten to add, however, this is
not the fault of the criteria set up by the International
Joint Commission in 1950 and adopted by both Canada
and  the United States in 1951  but an apparent break-
down in   communication  between Federal  and  state
government on our  side of the boundary and between
national and provincial government on  the Canadian
side.

   So here it must  be  concluded  in three cases that
water quality criteria set up as compliance aids have
failed to produce results for one reason or another.


   In answer  to  the second query of  our  Chairman:
"How can  they best be used?",  I  conclude thay they
can be used (1) as administrative, rather than enforce-
ment aids and (2) as aids to the implementing of such
provisions of law as are found in Section 2 (a) of the
Federal Water Pollution Control Act.  Here the inter-
relationship among  Federal, interstate, state, munici-
pal,  and industrial  agencies to obtain certain results
through comprehensive programs for water pollution
control  clearly  requires  soundly conceived criteria
that  are susceptible of fulfillment.


   Finally,  in answer  to query three:  "What  diffi-
culties presently impede  the  development and use of
water quality criteria for protecting aquatic life?", I

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                                      A Rational Industrial Viewpoint
would answer "lack of knowledge." Basic and applied
research for the most part would seem to be the answer
here.   This  research should  supply  the  enforcing
agency  with  solid answers to  back up their position
when restricting waste loadings.  Industries and mu-
nicipalities,  as  well as the enforcing agency, need to
know what  the  effect will be when  and if limiting
criteria are exceeded.
   Based on our experience, our conclusion is, there-
fore,  that  water  quality criteria to protect aquatic
life are useful tools  for  a state agency for planning
and administrative purposes.  They may or may not
prove  effective as an aid to  enforcement.  Finally,
much  is  still to  be learned through  research to
substantiate present assumptions and lay the ground-
work for future declarations of value.
             THE VALUE AND USE OF WATER QUALITY CRITERIA TO PROTECT AQUATIC LIFE:

                                 A RATIONAL INDUSTRIAL VIEWPOINT

                                              Roy F. Weston *
   The  speaker has been requested to give industry's
viewpoint on this complex subject. Surely, it is recog-
nized by all  that  no  individual can hope to present
the  many  diversified  and  sometimes  conflicting
opinions of the individual representatives of industry.
There are no  members of a group that typify rugged
individuals  more than those representing American
industry.  Nevertheless, there are factors common
to most industrial operations  that  make it possible
to  rationalize  an industrial  viewpoint.    I  have,
therefore, chosen the sub-title "A Rational Industrial
Viewpoint." The discussion below is my interpretation
of  a rational  industrial  viewpoint relative to  the
development, establishment, and enforcement of water
quality  criteria.

   Water quality criteria  for  aquatic life cannot be
considered  alone.   They  must be considered as a
specific part of a broad spectrum of criteria pertaining
to  numerous  different water  uses.   Their  mode
of application must conform with a general and sound
philosophy of  pollution  control.  Their enforcement
must be reasonable, equitable,  forceful, consistent,
and persistent.

   Commercial and sports fishing and hunting and the
recreational use of waters require proper protection
of aquatic life. These are reasonable and legitimate
uses deserving of protection. Therefore, water quality
criteria must  be established to protect  these  uses.
Such criteria  must be considered  essential to an
effective water pollution control program.

   Establishment  of  such criteria  is  required if
industry is to know specifically what is expected of it.

   Of course,  it  must  be remembered that aquatic
life  requirements  are  but a  few  of  the  many use
demands on  our  natural  waters.   They  must be
considered in their proper perspective.
* President, Roy F. Weston, Inc., Newtown Square, Pennsylvania.
   There  is competition for water.  It should be used
in a  manner  that protects the  rights of legitimate
users and is of best use to the greatest number.  In
other words, the use of natural waters  should be in
the public's best interests.

   Most  industrialists  will subscribe to the above
statements. Philosophical concept, however, confuses
the issue from now on.  There are those  who contend
that economics must control water use. They belittle
the value of a "few fish." They expound with confidence
that  jobs  are  more important than fish.  They state
that  we must  choose between fish or people, between
fishing  and working.   These  people  are sincere in
their beliefs.

   Such views are not necessarily industrial.  They
come from many different walks of life.

   The rational views of the  industrialist present a
special case.

   The  average industrial manager is interested in
pollution  control  for  three   interrelated reasons:

   1. To  maintain prosperous   business  levels
      through good public relations;

   2. to prevent  losses from forced plant  shut-
      downs,  costly  lawsuits,   or   claims  for
      damages;

   3. to  reduce  costs caused by lowered water
      quality.

   These  are  practical factors  unassociated  with
altruism.

   The corporate entity is created to serve society
and to reward its owners for  such service. It  cannot
exist if it does not make a profit.

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10
VALUE AND USE OF WATER QUALITY CRITERIA
   The primary purpose  of  the industrial  manager
is to assure a profit for his employer. He is trained
to demand due justification for every expense.  He
invests capital only on reasonable assurance of a high
rate of return.

   Water pollution control normally requires invest-
ment without  return.  In fact, it generally increases
operating costs in addition to increasing fixed costs.
Thereby, water pollution control  reduces  profits.
In  fact,  water pollution  abatement  at  an existing
plant may so alter  its economy as to create serious
economic  problems.   Therefore,   the  industrial
manager is  obliged to  abate pollution at minimum
cost  and to  delay  such  costs as long as possible.

   It should be obvious that the nature of his training,
experience,  and general  philosophy  influences  the
industrialist's views and policies concerning water
pollution control. The most reactionary industrialist
will  have the "job versus fish" philosophy and will
act accordingly.

   The most public-spirited industrialist cannot escape
his  inherent  philosophies, training,  experience,  and
responsibilities.   His  policies must, therefore, be
controlled by the  hard facts of economic  realism.

   This  does  not  mean  that the industrialist  has no
social conscience.  He does have a social conscience.
Twenty-three  years ago, when I was employed by
an industrial  concern to  work on their water pollution
abatement problems, I was advised that the executive
head of  that company stated the following philosophy:
 "The  cost  of  a company's product  to  the public
includes  the  price  paid  for the product plus  such
damages or  other  costs that may accrue  to  the
public as the  result of  the company's operations,
e.g., costs  of water pollution."  In view of the times,
this was a  most enlightened viewpoint.  Competitive
economics being what they are, however, this viewpoint
cannot be carried to extremes. Consequently, industry
is forced to use the philosophy of "enlightened self-
interest."

   Because the  costs of  pollution abatement affect
the  profitability of  the  industrialist's operations, it
is  reasonable that  he  should  adopt the philosophy
of providing no more reduction in pollution than is
necessary lo  accomplish  an immediate and  essential
objective.  He will  also reason that a balance should
be  made  between  costs  to industry and benefits
derived.  Most enlightened industrialists, I believe,
will agree that simple evaluations such as the cost
of pollution abatement  per  pound  of potential fish
production  from a  given stretch of stream cannot
be used to  justify pollution abatement. On  the other
hand, many  industrialists  may reasonably resist
demands to treat their  wastes to the extent  neces-
sary  to  make a short  stretch  of  a small stream
acceptable for normal aquatic life. This is particularly
true  if there  is no  other  compelling reason for such
a high degree of treatment.

   This  means, in  my  opinion, that the rational
industrial  viewpoint subscribes to  the  philosophy
that pollution  should be evaluated on the basis of socio-
                            economic effects as well as effects on water quality
                            per se.   In  any  case,  the viewpoint would require
                            "reasonable use "of available resources. For instance,
                            a waste water may be lethal  to  aquatic life without
                            dilution but harmless in the stream after dilution.
                            The use of stream dilution  in  such a case should
                            be a legitimate and reasonable water use.

                               This philosophy is sound economically. Obviously,
                            it  raises many  complex technical  questions.  Some
                            of these questions are:
                            How  shall  acute toxicity be  evaluated?  How  shall
                            chronic toxicity  be evaluated? What test procedures
                            shall  be used to  establish a biologically safe  con-
                            centration?   What organisms  shall be used as  test
                            animals and  plants?  What factor  of  safety  shall
                            be used in applying test results ? Who shall develop
                            and establish the necessary  standards for  testing
                            and applying test results?  How shall variation in
                            streamflow and  waste water quality be considered in
                            establishing allowable safe discharges?  How  shall
                            allowable discharges  be  allocated among industries,
                            and among  companies of  an  industry?  These are
                            but a  few of  the many practical questions that must
                            be answered.
                               Industry, I am sure, subscribes  to the need for
                            water quality  criteria to protect aquatic life. It will
                            expect that such criteria  be reasonable and as specific
                            as possible.   It will expect to be  required to meet
                            only   those  criteria that the  regulatory  agency is
                            prepared to monitor and to enforce.

                               Industry  realizes  that in many cases regulatory
                            action must  be  taken prior  to the  solution of all
                            technical aspects of a control problem. Nevertheless,
                            it  does  expect  professional  responsibility in the
                            development   of  water   quality   criteria.   Many
                            industrialists  feel  better if they are a party to the
                            development and establishment of such criteria.  The
                            cooperative industry-regulatory agency  development
                            of the temperature criteria in the State of Pennsylvania
                            is frequently used as an example of how such things
                            should be done.
                               It  should be  expected that  criteria cooperatively
                            developed will be technically sound and will clearly
                            define conditions  of use.   Procedures  should be
                            available and specified  for estimating biologically
                            safe concentrations of chemicals or wastes. Moreover,
                            procedures to  be used  for determining compliance
                            with the criteria should be specifically outlined. Such
                            procedures  and information are necessary for the
                            design of treatment  or  control facilities, or  both,
                            and for checking compliance.
                               The establishment of sound criteria and supporting
                            test procedures is highly complex, particulary if both
                            chronic and acute toxicities must be covered.  Just
                            as complex is the application  of such criteria. Two
                            basic  areas of responsibility are involved.
                               1.  The establishment  of  biologically  safe con-
                                  centrations for the specific  chemicals or
                                  combinations thereof in an industrial waste-
                                  water discharge.
                               2.  The establishment of the allowable discharges
                                  of specific chemicals or combinations thereof
                                  from individual plants.

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                                      A Rational Industrial Viewpoint
                                                11
   It is believed that the first area is the responsibility
of the industry  involved.  The burden of proof for
establishing the acceptability of an industrial waste
discharge rests upon industry.  This is based on the
philosophy that the discharge  of waste is a privilege
rather than a right.  This argument may be countered
with the theory that a polluter is innocent of causing
harm until proven guilty.

   The  establishment of allowable discharges is a
regulatory agency's  responsibility.   " Since  the  in-
dustrial  community  on  a  stream  is  dynamic, the
regulatory agency is faced with a complex  problem
in equity.   For instance,  at this particular time,
a  stream  can be adequately protected, in the case
of minimum 5-year flow, if each plant removes 50
percent  of the  toxic  materials  from its  wastes.
Adequate protection could be  assumed  if the biolo-
gically safe concentration of a toxic chemical existed
for normal industry waste water flow and concentration.
Now,  let us  assume  that Plant A and Plant B make
the same  product and  discharge the same type of
waste.  Plant A, however, discharges twice as much
toxic  chemical  per unit of production as Plant B,
because  of  poor  in-plant   control facilities and
procedures.  This factor should, therefore,  be con-
sidered in determining the degree of treatment re-
quired by Plant A as  compared with Plant  B. This
problem can be simply and equitably handled by relating
the allowable discharge of toxic  chemicals  to pro-
duction.

   Now, if Plant C discharges the same toxic chemical
as  Plants A  and B  (for the sake of simplicity),
but  makes  a  different  product using  different
processes, it is  apparent that the regulatory agency
is faced with  a difficult problem of allocation of
allowable chemical  discharge.   In  those  cases in
which  simple direct comparisons cannot be made,
other criterion for comparison may be provided, such
as net worth to  the  community, by which payroll,
taxes paid, or some other basis is used for comparative
purposes.  In time, equitable criteria for determining
such discharges must be developed.

   There are  those who will argue that the theory of
"reasonable  use" of a  stream's  pollution-carrying
capacity  is unreasonably complex and impractical
from an administrative viewpoint.  They would prefer
to use the expedient of requiring  all industry to
provide the highest practicable degree of treatment
available so as to discharge the minimum practicable
quantity  of pollution.    This  concept is subject to
arbitrary rather  than rational decision making.  It
can be uneconomical and mysterious, confusing and
frustrating to those subject to its enforcement.  The
philosophy of enforcement and control should be easily
rationalized technically, economically, and equitably.

   In  a general sense, all regulatory agencies recog-
nize that relatively small quantities of pollution can
be permitted in a relatively large  stream. Therefore,
our  large  rivers receive effluents  from  primary
treatment  plants  in some cases and  in many cases
receive polluting  materials that have been unaltered
prior to discharge.  In  other cases, a higher rate of
waste  discharge is allowable at flood stage than at
low flow.  Moreover, municipalities and industries that
discharge  into  the  sea  frequently  are required to
provide primary  treatment only.   These and many
other illustrations indicate that historically and in
current  practice  those  who  administer   stream
protection laws recognize the concept of "reasonable
use."

   In many river basins,  regulatory  agencies  are
currently  faced  with  the  problem  of   equitable
allocation   of   allowable   pollution  load  because
the pollution-carry ing capacity  of the stream is rela-
tively small compared with the discharge of polluting
materials.  Unfortunately, they have little precedent
for sound decision making. This situation will occur
and reoccur in  the future.

   In consideration of established practices and  the
problems of the future, it is quite obvious that the
development and use of water quality criteria to protect
aquatic life present highly complextechnicalproblems
and equally complex administrative problems.   The
establishment of sound criteria will require the team
approach and the best talent available in the biological,
chemical, hydrologic, engineering, and administrative
professions. The  criteria developed must be reason-
able, equitable, measurable, enforceable, and enforced.
Considerable research effort  is necessary to assure
the development and sound application of such criteria.

   It  is believed that  the industrialist recognizes
that  water quality criteria are  essential to a sound
water pollution control program.   He  is aware  that
such criteria  can be of  significant assistance to him
in determining his pollution abatement problem, in
defining  his treatment  or control requirements, in
determining his capital budget needs, and indesigning
and  operating  his treatment or  control facilities.

   He trusts that  the development of such criteria
will  recognize  and define  the concept of "reasonable
use."   He  understands  and respects those criteria
developed by industry-regulatory agency cooperative
effort.   He acknowledges  the  need for  regulatory
action  to abate pollution  prior to resolution of  the
many  technical  and administrative  ramifications
inherent  in the  development,  establishment,  and
enforcement of sound criteria.
   He recognizes that the development and administra-
tion of water quality criteria pose a great challenge
to the  water pollution control profession.  He must
urge that profound thought, extensive research, and
responsible action be  the basis for the development,
establishment, and enforcement of  water  quality
criteria.

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12
VALUE AND USE OF WATER QUALITY CRITERIA
          THE VALUE AND USE OF WATER QUALITY CRITERIA IN CONSERVATION PROGRAMS

                                           Thomas L. Kimball *
   Today there are 66 million-plus outdoor hobbyists.
In pursuing the pleasures of outdoor recreation, the
activity of most of these teeming millions is oriented
on or adjacent to water.

   By the year  2010  it is estimated by the National
Part Service that  the demand for outdoor recreation
will exceed present activity by 40 times.

   The United States Geological Survey reported in a
news release from the Department of Interior on May
7, 1962,  that the  use  of water  in  the United States
increased  12 percent between 1955 and 1960. The
report went on  to state that  270,000 million gallons
of water per day  (mgd) was  withdrawn for a multi-
plicity of uses, but only  61,000 mgd was consumed.
Approximately 77 percent of the total water withdrawn
for use  was returned  to the source, much of it in
a deteriorated or polluted condition.

   The  Senate  Select Committee on National Water
Resources reported the following on the amounts of
water needed for fish and wildlife purposes.

   It  is  estimated that by 1980,  66.7 mgd would be
needed  for consumptive  use to maintain important
wetland habitats for  waterfowl and  other species of
wildlife; by  2000, 89.9 mgd will be  needed for the
same purpose.  In  1955, the maintenance of sport fish
habitats required a flow of 78 mgd. By 1980, the need
to enhance stream fisheries to meet the demand will
require 171 mgd, and by 2000, 241.4 mgd.

   In 1954,  it took an estimated 512.4 mgd  for waste
dilution to maintain dissolved oxygen at an average
of  4 milligrams   per   liter.   This estimate was
based on a 70 percent treatment for  municipal sewage
and 50 percent  treatment for industrial wastes, both
higher than actually  prevailed.  If it is assumed that
pollution abatement will proceed  as scheduled, it is
estimated  that  332.2 mgd will be needed for waste
dilution in 1980 and 446.5 mgd by 2000.

   These  facts  are  mentioned  together for three
specific  reasons.   The  first is to draw  attention
to the popularity of water-oriented outdoor activity;
practically  all  of  our  adult population participates
in some form of outdoor recreation.   The  second is
to show the ever-increasing demands on our water
supply for a wide variety of uses, and the third is to
poin*  out  that waste  dilution  in 1954 was the largest
single use of water.  Perhaps a  specific and typical
example of water  wasted for pollution dilution would
be enlightening.

   The United States Corps of Army Engineers recently
presented a plan for the development of water in the
                           Potomac  Basin.   The program called for the con-
                           struction of 16 high dams within the Basin at a cost of
                           several   hundred  million  dollars.   The primary
                           objective of  the plan was  to  establish a continuous
                           delivery  of 3 billion gallons of water per day (gpd)
                           for domestic, industrial, and recreational use and for
                           water quality  control for the  Washington,  D.  C.,
                           area.  Fully two-thirds of this flow, or approximately
                           2  billion  gpd, was needed for pollution dilution. This
                           information  immediately raised the  question in  the
                           minds of  many public-spirited citizens whether or not
                           funds  allocated for pollution dilution  might be much
                           more  wisely  spent in pollution abatement; this would
                           permit re-use of the amount of water needed for waste
                           dilution,  while  saving  many fertile  and productive
                           river  bottom  lands   and  many  important  areas
                           of historic and scenic value from inundation.

                              These statistics illustrate that water demands  are
                           increasing in geometric proportions and, if all water
                           needs in  the  public interest are to be met, we cannot
                           long  continue to render unfit for re-use any portion
                           of our available supply.  Assuming this to be a worthy
                           objective, let us explore the  possibility and mechanics
                           of accomplishment.

                              Water experts have stated on occasion that "the
                           dependable supply  of water is not a fixed amount but
                           can be increased by surface storage, and the reduction
                           of evaporation and transpiration losses or other forms
                           of waste."    Conservationists are most  anxious to
                           maintain  our watersheds in  a condition that will insure
                           soil  stability and  a  sustained  maximum  yield of
                           quality water. This goal can be attained only through
                           wise  use and management  of the timber, forage,  and
                           mineral  resources.   Pollution abatement, however,
                           offers the most difficult challenge and a real opportun-
                           ity to provide the greatest  single contribution toward
                           an increased, usable water  supply.

                              The Congress recently  amended and strengthened
                           the Federal  Water Pollution Control Act. Additional
                           funds  were made available  as  grants-in-aid to states
                           and  municipalities  in an effort to encourage adequate
                           sewage treatment.  Federal enforcement authority was
                           increased and enlarged to  cover both interstate and,
                           where local and state authorities had demonstrated an
                           inability  to cope with pollution problems, intrastate
                           waters.  No law is  effective without adequate enforce-
                           ment.  No enforcement of water law  can be adequate
                           without a definite  set  of  standards established by
                           competent research.

                              The United States Public Health Service has done
                           a  creditable  job in establishing standards of water
                           quality for the protection of human health. From the
                           conservationist's viewpoint, however,  these standards
* Executive Director National Wildlife Federation,Washington, D.C.

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                                          Conservation Programs
                                                13
seem based on a premise that permits accumulation of
waste  materials in water up to the point where such
contamination  adversely  affects human health. Very
little information is available on the concentrations of
various pollutants  that are harmful to fish, wildlife,
and  recreational  potential.   This  position,  which
permits pollution to the  point of direct harm, can be
readily understood since removing  all deleterious
substances from water to create a dependable supply
for a wide variety of uses is expensive and depends
on the ability  and  willingness of the user to pay the
costs involved. It is my contention, however, that the
time has now arrived in the over-all population growth
and economic  development of our nation when we can
no longer afford to permit a water user to withdraw
any quantity of water from our lakes and streams with-
out requiring him  to return it to the source in such
quality as to  permit its re-use by all other  legitimate
users.

   As a conservationist and one interested primarily in
the welfare of our nation's wildlife, let me now discuss
the value and use of water quality criteria in  conserva-
tion programs. As the former Director of Game and
Fish in Arizona and Colorado, I had the opportunity to
struggle with the  administration and enforcement of
state  pollution laws affecting wildlife.  Both states
have what is considered  by most observers to be an
effectual and efficient anti-pollution law. Relative to
the wildlife resource, the Colorado state law contained
the provision that "no deleterious substance adversely
affecting fish shall  be permitted to enter the waters of
the State."


   After a few court cases it was soon apparent that
the  burden  of proving  substances  or  effluents
deleterious  to  fish life was the difficult task of the
prosecution.    The mere fact  that thousands of fish
were found dead was not sufficient evidence that certain
pollutants were the cause. Fish population studies had
to be conducted above  and below suspected  sources
of contamination.   Proof of fish losses was further
complicated by the fact that most fish killed by pollution
usually sink to the  bottom of  the  stream  or lake.

   Laboratory  work simulating polluted water condi-
tions had to be  initiated. Intense studies of  the entire
aquatic biota by highly educated and professionally
trained personnel who could qualify as experts on the
witness stand became a necessity.

   An  understanding  of  the  interrelationships  of
aquatic vegetation,  associated organisms, and insects
that meet the dietary requirements of a wide variety of
fishes is essential in the development of water quality
standards  designed to protect the fisheries resource.
In fact without such information successful prosecution
of  pollution  cases  is  difficult if  not impossible.

   The number of technically  trained people capable
of developing water quality standards for the protection
of aquatic organisms is woefully inadequate at both
the  state  and federal level.   What is needed is a
sufficient  research  staff with  adequate laboratory
facilities to develop  water quality   criteria  for all
recreational uses of water as well  as for industrial
and  public health purposes.  Standards so established
and  backed by competent research work can exercise
a  telling influence  for  good  on pollution before it
happens and exercise a potent and authoritative effect
in the courts on those who insist on flouting the law.
All water  users have a right to know in advance what
effect possible pollutants will have on the relative
quality of  water.  If this  type of information can be
provided to new industries, positive preventative pollu-
tion abatement can be initiated.

   Coordination of effort and the elimination of duplica-
tion among sanitary  engineers,  doctors, and aquatic
biologists  at the local, state,  and national level are
desirable. We need to develop water quality standards
for all legitimate uses of water, including all types
of outdoor recreation.  We  should not  rest until we
have the trained staff, the laboratory facilities, and
ample funds to do the job.

   Even when  water quality standards have  been
established,  the fight will  not yet be won. There will
be  reluctant  district attorneys,  attorney  generals,
governors,  members of  congress,  and officers
within the executive branch of government who will be
unwilling for personal or political reasons to prosecute
to the  full extent of  the law for the maintenance of
clean water. There will be individuals, partnerships,
corporations,  municipalities,   industrialists,  and
portions of  the great American public  who will be
unwilling to pay the  price for research to produce
standards  and the necessary  development and  con-
struction to  obtain water  quality. We cannot, in my
humble opinion, procrastinate any further.  We mast
have enforced water quality standards  to meet the
ever increasing demands of the many and varied uses
of this  important  renewable  resource.   We must
eliminate the great American tragedy of utilizing for
waste dilution the greater percentage of water with-
drawals from our limited supply.  Anything less will
inhibit the economic and  cultural growth of our nation
and  place  us  among the  historic civilizations who
wasted and squandered their national  inheritance.

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14
VALUE AND USE OF WATER QUALITY CRITERIA
                          THE VALUE AND USE OF WATER QUALITY CRITERIA

                                              DISCUSSION
   Mr.  Beak  opened the discussion by  expressing
the  opinion  that  water  quality  criteria  could  be
developed  without  interfering with the  solution  of
everyday  problems.    He  felt  that  research and
day-to-day operations should not be in competition.
Research should be  carried on for the setting  up
of criteria that can be used in the field.  He strongly
asserted that  more  knowledge  is  needed if we are
to improve our  field methods,  which are much in
need of improvement.

Dr.  Ronald Allanson, National  Institute  for Water
Research, Republic of South Africa.

   I  am  interested  in  what has  been said by the
panel,  particularly by  Mr.  Kimball,  because it is
exactly what   we in  South  Africa have been en-
deavoring  to  put  into  practice.   I think  it might
be of  interest to the members if I outline the way
in which  we  work.  There  is a  tendency to place
upon industry the responsibility for the purification
of their wastes.  The purification of wastes is ex-
pensive, but as I said to one of our gold producers
at a meeting of the Committee, it may be necessary.
This  company receives water  from a big private
water  purification  system,  and  they pay a shilling
per thousand gallons. At that cost they can econom-
ically produce gold, but with an increase  in pollution
and  the  consequent purification that would be nec-
essary, they would have to pay more than 2 shillings
per  thousand  gallons for their water.  Under these
conditions, the price of  gold and the cost of mining
it would be uneconomical.  Industry in the Republic
of South  Africa is nowhere near  the  size of that
in your country and nowhere near as complex, but in
miniature we  have a very similar problem. We have
national and provincial governments similar to those
in Canada.   There is  a  Council  of Water Affairs,
which  is  responsible  for   all  water  uses in  the
country — recreational,   industrial, and  municipal.
This body is  advised by  the Bureau of Standards,
which  standardizes  all sorts  of  things,  even  the
quality  of  Coca  Cola.   They have standardized the
quality of effluent that may be discharged into rivers.
I'm extremely  interested in Mr. Kimball's remarks
that  what Americans should do is think and work
actively  so  as  to  return  water  eventually to  its
source in a condition suitable for  another use. The
Water  Act of 1955 for  the  Republic of South Africa
indicates  very clearly  that water  used  by any in-
dustrial  activity  must  be returned, if possible,  to
the original  watercourse  from which  it was de-
rived,  or to  another  watercourse.    The Act also
includes sewage works as part of an industrial under-
taking.  The standards  promulgated in South Africa
by the  Council of Water Affairs through the South
African Bureau of Standards have rested very clearly
upon intensive  research in the field of river biology,
                            river  chemistry, and river physics, which has been
                            carried  out by the  Research Institute that I repre-
                            sent  here  at this   meeting.   These  standards are
                            from your  point of  view unrealistic.   For example,
                            the standards specify that the effluent must not con-
                            tain  more  than  100  fecal  E. coli per  liter, one
                            hundred percent of  the  time; that it must not contain
                            more  than  10 ppm of ammonia nitrogen, or have a
                            BOD  of more  than  10 ppm.   Industry  is of course
                            appalled at this standard, but the  way we work with
                            industry is to  present to them that this standard is
                            a basis for assessing  violations,  but that exemp-
                            tions  can  be made  and the Act acknowledges that
                            exemptions can occur.  We urge  industry, whether
                            it be a local product manufacturer, a sewage works,
                            or a  big national   industry like the  steel industry,
                            to  apply to the Department of Water  Affairs  for
                            exemption from one or all of these standards.  Ex-
                            emptions are allowed only  after consultation around
                            the table by the industry, the research organizations
                            concerned,  the Institute, and the Bureau of Standards,
                            together with the Department of Water Affairs.  We
                            ask the industry what it is physically able to do at
                            the moment and based on discussion we recommend
                            to  the Ministry of Water Affairs that an exemption
                            be made  specific for the particular item that varies
                            from  the   general  standards.    We lay down one
                            condition,  however,  and that is that  this particular
                            industry, whether it be a large national government
                            body  or a  small private place, must attempt in the
                            following 5 years, or however many years we decide,
                            to improve the quality of its effluent so that it comes
                            nearer to the general standards.  This  might sound
                            complicated and rather idealistic, but I can assure
                            you that it works.  I remember one case of a steel
                            corporation in  South Africa that was appalled when
                            we laid down  certain  requirements for their re-
                            sponsibility to the  national group; I was most grati-
                            fied to sit on the Committee a few weeks ago and real-
                            ize that the report we  had before us represented a
                            very   real  improvement in their whole water  ef-
                            fluent purification.   But, as I  say, this can be done
                            in  South  Africa because we have  this organization.
                            It is  in essence what Mr. Kimball is asking for and
                            what  we  in South  Africa are  trying to do. I must
                            say,  and  again support  Mr.  Kimball, that water
                            quality standards must rest upon fundamental and
                            applied research.   If the biologist and  the chemist
                            and the physicist  are  called in at  every possible
                            level, this coordination will work.

                            Mr. Stein

                              There was  one  remark  I omitted from my talk
                            and I  am, therefore,  very happy you brought this up,
                            Dr.  Allanson,   because you  and Mr. Weston have
                            made  some remarks  that put this problem in focus.
                            Mr. Weston was speaking about the establishment of
                            safe concentrations.  You don't get BOD's when you

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                                                Discussion
                                                                                                       15
talk about the establishment of safe concentrations or
allowable  discharges.   I  might point out from a
logical point of view that this is not the only way to
establish criteria;  that is,  to dump into the stream
as  much as you  can possibly  get away with.  The
other technique is  that exemplified by the Food and
Drug Administration where,  if  an element is con-
sidered deleterious or poisonous,  even a trace of it
cannot be  introduced into a food.  I  think the South
African  research possibly  tends  more  toward the
Food and Drug approach.   Mr. Weston's experience
tends more to what we  assume  here when we think
of  criteria.   In your deliberations, you  should not
forget that. Another approach in  establishing criteria
is  to put  them at a minimum,  and not necessarily
assume  that the  only  type of  criteria are those,
so  prevalent in this country,  that allow  everything
possible  to be put into a stream.

Mr. Kimball

   You might say,  Dr. Allanson, that that particular
experience  is   unique to your  country.   We  have
similar  problems  here  in  the  United  States about
the use  of chemicals for  insecticides, pesticides,
and  other  purposes.  This matter, again,  is quite
a challenge to  the  team of  research scientists.  To
my way  of thinking there are other chemicals that
possibly  could control aquatic vegetation in certain
ways and  not  be deleterious  to fish life or to the
biota in  a stream.  The problem here in America
is that we just haven't had sufficient money allocated
to  the research teams  to  provide this type  of in-
formation.  I am quite sure that our team of scien-
tists  is  up to  any  challenge put to them. Certainly
if we  can put  men  in  space  and if interplanetary
travel is something that can be  looked forward to in
the  near  future,  there isn't  anything beyond  ac-
complishment as far as improved technology in any
of these  sciences is  concerned,  given the necessary
funds and time.

   So if  the problem is  one of agriculture vs. fish-
eries or recreational developments, there are other
ways and means of desirable control that still pro-
tect the  fisheries  values of the stream.  To me at
least this is  the answer.  We  do not have to make a
choice between fisheries  and navigation, for example,
by  elimination of  a plant at  the expense  of the
fisheries.   In  my  opinion,  if given the proper time
and money, we  canhave both with improved technology.

Dr. Tarzwell

   I believe  we  need to define  some of our terms,
for misunderstanding appears to exist.   It is quite
apparent that  there  is no general agreement as to
what is meant by pollution, toxicity, and water quality
criteria.  The  term  "pollution" is  often very loosely
used and appears to  have different meanings to dif-
ferent groups.  To me, water pollution is the addition
of any material or any change in  character or quality
of a water that interferes with, lessens, or destroys
a desired use.  Pollution is, therefore, tied to use;
if there  is no  interference with a use, there is no
pollution.  When we say a material is a pollutant or
that a stream  is  polluted, we should be indicating
that a use of the water  has been adversely affected.
   "Toxicity" is a quantitative term.  Many materials
become toxic  if they are present in high concentra-
tions.   Even common table salt, an everyday neces-
sity,  is toxic  if  taken  in  large  amounts.  Many of
you recall the recent poisoning of babies in a hospital
when salt was used instead of sugar.   Several ma-
terials  that are potential toxicants are required in
small  quantities  by  many  living things.   Certain
trace elements  are  essential for  life.   Phosphorus,
nitrates, copper, zinc, sulphur, molybdenum, potas-
sium,  manganese,  boron,  and  chromium  are all
necessary, but when they exceed  certain levels they
become toxic.   An outstanding example is selenium;
it  is extremely toxic, but it has been found to be one
of the most important trace  elements  essential for
life.   In short, many materials must  be present in
the water in small quantities if we are to have aquatic
life.  These and many other materials become toxic
only when they  exceed certain  concentrations.  In
view of these facts, how can we say no  toxicant shall
be added to a  stream ?  I believe we  must say that
these materials must not exceed a certain concentra-
tion  in the  stream.  Why pay the  cost of complete
removal from waste waters if these materials occur
naturally  in  the water  and are  needed?  Removal
is a costly  process, especially the removal of that
last  small fraction of a percent.  Why pay the extra
cost  for  complete  removal  of  that small amount
that is not harmful?

   Now, as to the meaning of "water quality criteria."
The  purpose  of water quality criteria for aquatic
life  is  to maintain or restore those environmental
conditions that  are essential  for survival, growth,
reproduction,  general well being, and  production of
a crop  of the desired aquatic  organisms.   Since the
purpose of these water quality criteria is to maintain
or  restore  a favorable  environment,  the  criteria
must be based on a  thorough knowledge of the en-
vironmental  requirements  of those organisms we
seek  to  protect.  Our knowledge of these require-
ments is limited.  We need to know much more.  This
means  a research program.   Detailed toxicological
information  cannot  be gained by field observations
alone  or by  a case-by-case  study of fish kills.
We have been doing that for 50 years and we haven't
come up with the answers.

   With  our  present knowledge, it wouldn't make
much  difference  whether or  not a biologist were
present during  a fish kill due to a toxicant. Gen-
erally,  he couldn't determine the cause in the field.
At present,  neither  biologists  nor other groups  can
tell  much about the cause of fish kills.  We can
tell  if  the temperature is too high or the oxygen
too low, if  they  are really  high or low. We have
developed a method of detecting cyanide, but it was
developed by laboratory research.  Recently, in our
Newtown  laboratory,  we  developed a  method  of
determining kills due to heavy metals.  Water quality
criteria for aquatic life can be developed only through
research.

   I  have never suggested that environmental  re-
quirements  be  arrived at  by a group in a meeting
where a consensus is obtained.   I do not believe
this  group  feels that the  conference or  meeting

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16
VALUE AND USE OF WATER QUALITY CRITERIA
method is  any way to settle  biological problems.
Groups meeting for such purposes are usually com-
posed  of  nonbiologists.   Group discussions without
data can never produce good criteria.  Water can-
not rise above its  source.  There has been too much
talk,  too many meetings, too much money spent on
this unproductive procedure. We must have research
to assemble the  needed facts.  Meetings, arguments,
and  the seeking  of a consensus should be directed
to determining what use or uses will be given pre-
ference  in  a  given  stream  in  view  of  the local
situation, and the requirements for each use.

   I agree completely with  Mr. Stein that discussion
is  no  way  to  set  water quality  criteria.  I cannot
agree  with him, however,  when he  says we  do not
need criteria,  that we should go out on the stream,
determine  what is wrong, and correct it.  How can
we determine what is  wrong  if we  do  not know
definitely what is required?

   Let  us  look at the problem from another point
of view.  The time has now passed, in many sections
of  our country,  when we  can afford the  luxury of
using  water  only  once.   Our  future  fresh-water
needs  can be  met  only  by re-use.   Effective and
efficient re-use  means  that each user  must return
the used water to the stream  in such condition that
it is suitable for another use. To do this econom-
ically and efficiently, he must know the quality of water
required for  the next desired use.  Gentlemen, we
do not know definitely the water quality required for
all uses.   To put it bluntly, in many instances we do
not know our objectives in pollution abatement. Neither
do we know definitely our objectives for waste  treat-
ment.   Without  this knowledge, how can we  detect
and evaluate pollution concisely? We've had the cart
before the horse for too long.  For too long we have
been  making field observations;  determining BOD,
conductivity, etc.;  and analyzing water  samples for
a few materials for  which we  have field or well-
tested analytical procedures.   What  do we do with
these  data?   How  can we apply them?  We are at a
loss. We put the  material in a cubbyhole.

   Let  me illustrate. Recently I had a letter from
a man in  Ohio.    He said he'd had a phenol prob-
lem.   He had found phenol  in the body of fish. What
does he do with the data? I told him we have had other
problems like this,  come  on down,  and let  us get
down  to  brass  tacks and discuss  the essentials.
How much phenol is harmful?  What  is the relation
between the amount of  phenol in the water and the
amount found  in the  fish?   Phenol  data  are often
collected because we have  an  analytical method for
phenol.  In the past, much  data have been collected
only because it was  customary.  There was no defi-
nite idea  about  how  the data would be used. It is
past time  to stop  this busy work.  Analyses  to de-
termine the amounts of materials present have little
meaning if we do not know  the levels that are harm-
ful.  When these levels are known,  however, these
analyses are meaningful.

   We must  know the water quality required for each
use. This will take research and time and, of course,
we can't get the  answers all at once. We must have
                            some answers, however, before we can deter mine what
                            waste  treatment is  needed.   At present  many waste
                            treatment  requirements are based on opinion.  Since
                            opinions differ, requirements  differ  or are changed
                            as administrators change.
                              This  group is here for the purpose of summar-
                            izing our knowledge on water quality criteria.  Your
                            program shows the approach we are taking; we're not
                            just discussing criteria, we're not coming together
                            to decide in committee what criteria should be. The
                            program deals  with the environmental requirements
                            of aquatic life.  This is because water quality criteria
                            for the protection of aquatic life must be based on an
                            adequate  knowledge of  the  requirements  of  those
                            organisms we intend to protect. If you'll look through
                            your program,  you  will see that we  are  dealing with
                            the requirements for the various groups of organisms.

                              In  the  setting of criteria we must be governed
                            by the need; that  is,  the quality  of water required
                            for a  specific  use.  When the scientist determines
                            or suggests water  quality criteria,  he must pay no
                            attention  to economics.   Let me  illustrate.   If you
                            were making ball bearings and you  were told  these
                            must  have a  certain  diameter  with a tolerance of
                            0.001  inch,  would  you be saving money if you re-
                            duced  the  cost  of  production by  using a tolerance
                            of 0.1 inch?  The operation would cost less, but you
                            would  be  wasting  time  since the product wouldn't
                            meet  the  need.  The  same  thing applies to  water
                            quality criteria; they must meet the need — insure
                            the quality of water required  — or they are useless.
                            Economics enter the picture when the proper author-
                            ities decide what use or uses will be given preference
                            on a  certain  stream.   The criteria must  define
                            definitely  the  quality of  water required for the use
                            in question.

                              Water  quality  criteria have definite uses  and
                            values for  meeting  the pollution problem.  They en-
                            able us to detect and evaluate pollution.   They de-
                            fine our objectives  in  pollution abatement and  waste
                            treatment.   They supply definite information on what
                            is needed  and provide  information that will allow the
                            general  public  to be a more  effective force in pol-
                            lution  abatement.  If carefully documented and ade-
                            quately explained, they  should result in more uniform
                            regulations.   This  will  reduce the practice of  one
                            locality  bidding against  another for  a  desired in-
                            dustry and making  concessions at the expense  of the
                            aquatic resource.

                              Criteria for all  water uses will be the most im-
                            portant and the  strongest tool  we  can  use in legal
                            procedures for the  abatement of pollution. They will
                            define the  objectives  that must be met.  With our
                            present lack of knowledge many enforcement actions
                            result in  long  agruments about what is or  is not
                            harmful, what levels are or  are not toxic, and what
                            effects are  or are  not  significant.  In  such a situ-
                            ation,  short-term bioassay tests can be used against
                            the  public  interests.    The  defense may make  a
                            bioassay  with  resistant  adult fish, using in the test
                            solution a concentration  of waste comparable to that
                            in the receiving stream.  The fish are taken out just
                            before they  die and nothing is said  about their con-
                            dition  at  the  end  of  the test.   Then the defense

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                                                Discussion
                                                                                                       17
attorney presents the data and asks, "Can fish live
for x  hours  at  a concentration comparable to that
in the  receiving  stream?  Yes or no."  You answer
"yes"  since they did  live, and, without knowledge
of the  concentrations  of  the  wastes  that are  safe
under  conditions of continuous  exposure, you cannot
establish that such  levels are not  satisfactory for
the survival  of  the  species.  We must  realize that
environmental conditions  that  the adult may resist
for even long periods may be entirely unsatisfactory
for the  survival of the species. We  are not inter-
ested in just  the lethal effect.  We are interested in
levels  that  are not harmful and that do not interfere
with productivity.   If we have  well-documented
criteria, and  if  they are accepted,  we  will be in a
much  stronger  position in legal actions to abate
pollution.   Then  the  question  would be: Are these
conditions,  as defined by  the  criteria,  being met?
If they  are  not,  pollution  exists  and  there  is a
violation.   I  am convinced that criteria can serve
as a firm basis  for  legal action when it is required.

   Surveys  to determine if pollution exists become
meaningful  when the  quality of water required for a
given use  is  known.  When safe levels  of toxicants
are known, chemical analyses have meaning. Chemi-
cal analyses then become a tool to  determine com-
pliance.  There is a real need to meet problems in
this  way.   The  application of criteria  and  the en-
forcement  of  regulations are not in  the  field of the
scientist.   It  is  his duty to determine the facts and
present  the needed information.  This seminar has
as its  purposes the summarization of present know-
ledge of the environmental requirements of  aquatic
organisms,  the presentation  of problems, the des-
cription  of  new methods and approaches,  the exciting
of interest, the  exchange  of information,  and the
promotion of  good will and cooperation both nation-
ally and internationally.  It is  my sincere hope that
it will be of value to you.

Mr. Weston

   Dr. Tarzwell,  as a  consultant,   I can't help but
agree with  the technical aspects of the problem that
you have raised, and  certainly you must have the
technical know-how.  There are two big factors we
haven't  talked about  here today that are  of  vital
importance  — one is social acceptance and the other
is social economics. Maybe these are  coined words,
but I'll use these particular terms.   I'd like to  give
as  an  illustration  a  situation on  a stream  in a
Pennsylvania  area in which we have had considerable
complaint concerning the froth,  the suds,  and the
toxicity to  aquatic life  caused by detergents used by
housewives.   The  housewives  have  come to public
meetings and have  indicated  their  indignation  that
such a situation  should exist.   It was  pointed out to
them  that their current sewage treatment facilities
are incapable  of removing the synthetic detergents
from the wastes, but that if they as housewives would
use soap — common old Ivory  soap  or naphtha soap
— instead of the synthetic detergents  they would no
longer have that  condition in their streams.  Gentle-
men,  today  they  still  have suds in that  stream.
The housewives would not revert to  the  soap.  Here
we have a  matter of acceptance.  As  to economics,
they will not  supply  the  funds so  that the sewage
treatment plant can remove the synthetic detergents.
We know how they can  be removed today, but the
public will  not raise the funds  needed to  remove
them.   So,  I  think in addition to technology you've
got  to  have  social acceptance and  a  respect for
social economics.

Mr. Kimball

   May  I repeat what I  said before in connection
with water  quality  criteria problems.  It's my feel-
ing  that there is  no water  pollution problem too
great for our scientific teams to solve, and that the
standards  so  obtained should  be accepted  by the
people as essential to clean water. Sufficient time and
funds should be made available to these teams to do
the kind of job  that needs to be done.  Mr. Adams
has  stated  that detergents  can  be removed  from
effluent.  Maybe Murray  or  somebody else can tell
us how  much public funds have been made available
to find  out  whether or not this can be done economi-
cally.   If we're going to  finance pollution abatement
programs  solely  with funds  obtained   from  bond
issues,  we  never will get the job done.  Our present
efforts  are far from achieving  desired  results.
What is the  answer ?

Mr. Stein

   First,  we  do have  funds  that  we could  use for
research  on  detergents  but  we're  not  doing  this.
I commend  to you, however, one  of  Milt Adams'
suggestions  that a  manufacturer be  not permitted
to put out a product that is going to create a prob-
lem unless  he comes up  with a solution to it.  This
may  be something to consider.   West Germany,
you  know,   banned  the  use of  detergents.  For the
benefit  of the foreign  representatives we have here,
I think  we  should point out that we have a system of
justice  in  this  country  that  operates slightly  dif-
ferently from the  courts in other countries or  from
procedures  they may have witnessed on movie or TV
screens.   I doubt that there are very many cases
where the   judge will not permit an expert to give
his full views, but hold him to yes or no.  I haven't
experienced that.   By and large,  I think we get a
full hearing  in pollution cases.

   Secondly, I  don't  think  we're  losing  cases in
court because of not having scientific or biological
evidence.  The  cases just aren't brought into court,
because of  the pressure.  I think the gentleman from
Canada  raised the point of biological evidence.  Pos-
sibly  he missed the essential point or maybe he
doesn't  have  these conditions  in his country, but
in large segments  of the national program and in
state  after  state  in this  country we have seen in-
stances  where administrators in charge  of the pro-
gram for developing criteria, standards, and clas-
sification   have  gone  on  for  years and have not
cleaned   up  a  drop of pollution.   I agree there is
necessarily  no dichotomy between them; the practical
day-to-day  work and  the basic scientific  work can
both go  on  at one time.  Milt Adams has a distin-
guished   record  in Michigan he  can be proud of.
He  has  that  distinguished  record,  I submit,  pre-

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18
VALUE AND USE OF WATER QUALITY CRITERIA
cisely because he went out on a case-by-case basis
and  fought  to abate pollution in his 32-year tenure
in office.  He did not, as some state administrators
have  done,  wait  for  15 or  20 years  classifying
streams, getting at  the  legal battles of classifying
streams, and not cleaning up a bit  of pollution. We
have  more  data and more research coming out of
Milt Adams' operation in Michigan  than we have in
many  of  the  other  jurisdictions  that  have adopted
the other course.

Mr. Kimball

   Then,  in essence, you're  saying  that the problem
is not one of establishing standards of water quality,
but rather one of selling the public, pollution abate-
ment administrators, law enforcement officers, and
judges  on  an action program.   Through political
pressure, water polluters have been  able actually
to prevent  enforcement  cases from being consum-
mated.   This has  been the  reason for lack of ade-
quate  pollution  abatement  rather  than inadequate
water  quality standards.  Is that what you're saying ?

Mr. Stein

   Yes,  that's largely  what I'm  saying.   I'm also
saying  that  Tarzwell and  any of  his  compatriots
                            can  go  into  a particular  area and do exactly what
                            he says — throw  out the substances that are inter-
                            fering  with the normal use  of the water as far as
                            the  biology is concerned.    If we  proceed on that
                            basis,  we're  going  to  have  a  cleaned-up area.  I
                            also submit  that by  going  into area after  area,
                            finding out what  is   interfering  with  the  legitimate
                            water  use  from the point of  view  of a biologist,
                            presenting a description of that, an analysis of that,
                            and the facts  of that, we will be much farther along
                            than if we have these cozy little sessions to decide
                            what number  we  should put on a concentration that
                            will  be acceptable in one stream or another, because
                            what will  be  adequate  in a swift-moving  stream in
                            the  Pacific  Northwest won't be applicable  in the
                            Southwest.  We have many,  many  streams in this
                            country that are, as we say  (in law)  sui  generis —
                            that's pig latin for saying unique, in, of, or to them-
                            selves.   I think the  time has come  when we have to
                            hit this on a  case-by-case basis and get  ourselves
                            the building  blocks,  rather than go  down the path
                            you have  seen many  of these agencies take, fritter-
                            ing  away  their  time, their resources,  and their
                            energies  in maintaining an allowable limit of how
                            much we can possiblly dump into a stream.

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               ENVIRONMENTAL REQUIREMENTS OF PLANKTON ALGAE

                         AND THEIR EFFECTS ON WATER QUALITY
                                          G. E. Fogg, *  Chairman

                       DIATOMS AND THEIR PHYSICO-CHEMICAL ENVIRONMENT
                                          Charles W. Reimer^
   The primary purpose of this paper is to present
some measurements of the habitats  in  which five
selected  species  of  diatoms have been found, and to
assemble and  comment on some  of the ecological
remarks made about these species.

   Much  of the relative value from such a study rests
on  the  reasonable  assurance  that  the  information
gathered actually refers to the same species.  Many
diatom species are similar in morphological appear-
ance and it is my opinion that considerable misapplied
ecological  information is available  in the literature
under a  single  species  name which actually applies
to more than one taxon. In an attempt to minimize this
possibility,  the following relatively well-defined spe-
cies have been selected:  Melosira varians C. A. Ag.,
Nitzschia amphibia Grvn., Navicula confervacea Kiitz.,
Cymbella tumida (Breb.) V. H., and Navicula ingenua
Hust.  These species have rather  distinctive  valve
features  and,  with the  possible  exception  of N.
amphibia, do not seem  to belong to any such series
of closely related taxa.   This should increase the
probability  that the information gathered here does
refer to the species discussed.  Thefirstfour species
are rather widespread both in this country and through-
out the world,  and thus a larger number of observa-
tions are at hand for comparison.

   No attempt  was made to cover  all the published
literature on this subject, but rather to include those
larger works which appeared to have more extensive
physico-chemical  data.   Chemical  ranges compiled
from the literature were from the following sources:
Bourrelly and Manguin (1952), Cholnoky (1960) (1962),
Foged (1948)  (1949) (1951) (1953),  Hustedt  (1937)
(1938a)  (1938b)  (1939)  (1943)  (1957),  Kolbe (1927),
Niessen  (1956), Patrick and Freese (1961), Scheele
(1952), Schroeder (1939), and Sovereign (1958). Other
ecological  notes and comments were compiled from
the works  of other authors listed in the References.

   Ecological categories  used  by  other  authors  to
describe some of the physical and chemical tolerances
or preferences are mentioned here as they have been
applied to each  species.

   Our own chemical and distribution data are based
on surveys carried out by members of the Limnology
Department under the direction of Dr. Ruth Patrick.
One  series of data was processed in a computer using
data from 41  different  streams and rivers in the
United States and bracketed upper and lower physico-
chemical ranges.  A  second series  (from 59 areas)
was  assembled manually from data  on the following
rivers and creeks:  the San Joaquin (California), the
Potomac (Maryland),  the Tennessee  (Tennessee), the
Ottawa  (Ohio),  the  Auglaize  (Ohio),  the Savannah
(South Carolina-Georgia), Lower Three Runs Creek
(South Carolina),  the Schuylkill (Pennsylvania), and
Assunpink Creek (New Jersey).

   Although the species considered in this paper cannot
be considered truly planktonic, they are diatoms which
do occur from time  to time in the seston  of streams
and rivers, sometimes in appreciable numbers. Thus,
a study of  the  suspended organisms in a stream can
very possibly involve these  species.

             Melosira varians C.A. Ag.

   Table 1  shows  the ranges of chemical conditions
under  which  M. varians  has been observed.  For a
sample to be included in this tabulation the species
must have  occurred  at  least  six times  at  a mini-
mum count of 8,000 diatoms.

   For each sample there were accompanying chemi-
cal analyses  of water collected at the same time as
the diatoms.    Thus,  for example,  the number 132
in the  pH line  of Table 1 represents 132 composited
diatom samples in each  of which 8,000 of the diatoms
were present.

   The magnitude  of variation  in nearly every case
is great and  might  suggest that this diatom is in-
sensitive to changes in any of these factors. Since
much of the  ecological  terminology involves such
statements as  "relative numbers,"  "best  develop-
ment,"  "massive  growth,"  and the  like,  it  seemed
advisable  to   assemble  the  same  kind  of  data in
sample percentage groupings.  In Table  2 the per-
centage occurrence of M. varians plus the number of
samples within the percentage range is given.

   In most cases the greater physico-chemical ranges
are to be found where the diatom showed a frequency
of less than 1  percent.   At higher frequencies these
ranges narrowed.  These narrower ranges  can hardly
be considered  as more  reliable or  optimal for the
species  merely because  of  increased numbers in
the samples since the number of such observations
is very low, a factor which seems not always to have
been considered in classifying the physico-chemical
preferences of a species.
 *  Prof. Bot., Westfield College, London, England.
 t Associate Curator, Department of Limnology, Academy of Natural Sciences of Philadelphia, Philadelphia, Pennsylvania.
                                                  19

-------
20
ENVIRONMENTAL REQUIREMENTS OF PLANKTON ALGAE
      Table 1. PHYSICO-CHEMICAL DATA (COMPUTER) FOR MELOSIRA VARIANS C.A. AG. (00095)
         Factors
                               Ranges
No. of samples
         PH
         Temperature, °C
         Total hardness (as CaCOg), ppm
         PO4, ppm
         NO g  (as N), ppm
         NH3  (as N), ppm
         Alkalinity (M. O.)
            (as CaCO3), ppm
         SiOo, ppm
         Fe (soluble), ppm
         Cl, ppm
         SO4, ppm
                       <3.0  to 8.0 - 9.0
                       <12.0 to>40.0
                       <10.0 to 1000 - 5000
                       <0.001 to 5.0 - 10.0
                       <0.007 to 1.5 - 3.0
                       <0.001 to 10.0 -20.0
                       <10.0 to 200.0 - 550.0

                       <1.0  to>48.0
                       <0.01 to 1.0 - 5.0
                       <3.0  to 2500 - 10,000
                       <10.0 to 240 - 480
     132
     128
     134
     127
     130
     130
     134

     121
      91
     134
     118
    Table 2.  PERCENTAGE FREQUENCY OF PHYSICO-CHEMICAL DATA FOR MELOSIRA VARIANS AG.

Frequency,
percentage
<1
1
2
3
5
6
7
8
10
11
15
20
40
50
Range
Literature

No. of
samples
27
3
7
3
1
1
1
1
1
3
1
1
2
1




Frequency,
percentage
<1
1
2
3
5
6
7
8
10
11
15
20
40
50
Range
Literature


No. of
samples
27
3
7
3
1
1
1
1
1
3
1
1
2
1



PH
6.0-8.3
7.4-7.8
6.3-8.4
7.5-8.3
7.5-7.8
7.8
7.5-7.8
6.8-7.6
8.2
6.8-8.1
6.9-7.5
7.5
7.2-7.7
7.4
6.0-8.4
3.0-9.5

Temp.,
°C
10-32
20-30
11-27
20-36
20-22
30
20-22
17
31
9-28
16-17
26
16-27
26
9-36
0-40

Hardness (as
CaCO3), ppm
64-522
75-192
77-177
86-142
--
184
110-117
57-66
142
81-269
65-70
165
65-161
166
57-522
49-712

P04,
ppm
0.002-2.7
0.072-0.143
0.029-0.216
0.004-0.097
--
0.191
0.084-0.089
0.094-0.119
0.010
0.010-0.525
0.073-0.078
0.212
0.073-0.508
0.290
0.002-2.7
0.03-0.26

N03,
ppm N
0.00-4.92
0.052-0.427
0.00-0.873
0.049-0.426
__
0.47
0.049-0.052
0.069-0.120
0.57
0.02-1.3
0.022-0.069
1.4
0.02-1.5
1.6
0.00-4.92
0.2-1.70

Specific
conductivity
mho
1.2-9.8XHT4
1.5-5.8xlO-4
1.39-3.46xlO'4
1.6-3.8x10-4
-_
5.8x10-4
--
__
3.9xlO-4
1.4-5.9xlO'4
_-
4.5xlO-4
4.4xlO"4
4.6xlO'4
1.2x9.8xlO"4

Si02,
ppm
0.6-10
3.4-9.3
0.7-11.4
3.2-9.3
-.-
7.2
8.7-9.3
12.7-12.9
3.0
3.0-7.0
12.2-12.7
9.0
9.0-13.0
9.0
0.6-12.9
2.0x10-4-2.0x10-5 6




Fe,
ppm
<0.001-0.54
<0.002
<0.002-0.14
< 0.002
	
<0.002
<0.002
<0.002-<0.020
<0.001
0.001-0.089
0.002-0.021
<0.002
<0.002
<0.002
<0.001-0.54
Total
<2.5->10

ci,
ppm
6- 1470
14-192
14-306
8-180
876-1470
27
168-192
11-17
12
13-23
11-20
17
21
14
6-1470
16-2000


NH3,
ppm N
0.00-43.4
0.008-0.632
0.00-0.314
O.002-0.478
__
0.270
0.071-0.083
0.494-0.540
<0.001
C0.001-0.018
0.423-0.620
0.02
0.04-0.62
0.02
0.00-43.4
0.24-0.41
Alkalinity
(M. O.) (as
CaCO3), ppm
22-244
73-80
17-109
73-106
__
77
73-75
52-53
108
20-193
1
49
51-57
49
1-244
10-750


so4,
ppm
24-452
91-189
23-61
25-189
~_
140
91-189
23-25
57
45-152
20-32
149
20-160
155
20-452
	


DO,
%sat.
10-100
40-90
70-90
90-100
70
80
90
90
90
50-80
100
90
80
80
10-100
0-100+


-------
                             Diatoms and Their Physico-Chemical Environment
                                               21
   It is,  nevertheless, useful to have recorded such
ranges as  a starting point.  When we have assembled
as  much water chemistry data for massive-growth
occurrences  as we have for  small-number  occur-
rences, we might be  in  a  much better position to
delimit  the  conditions  for "massive  growth"  and
perhaps  to decide whether or not this coincides with
the "range of best development."

   Table 2 compares the chemical ranges in whichM.
varians has been found in our various stream sur-
veys, with ranges compiled from 35 works of other
investigators.

   Of the ranges given there is  no substantial dis-
agreement between our survey data and the record-
ings of others, though in some cases our ranges are
broader (e.g.,  SiO2  and PO^.

   The  following terms have been  used by various
authors to describe the apparent physical and chemi-
cal preferences of this species.

   Alkaliphil  (occurring around pH 7, with principal
distribution at  a pH  of over 7) — The few large
populations of this  species  observed here did occur
at a pH range slightly above  7. Thus, greatest  growt^
of the  species  has  been recorded in the range wher
others  have   reported best growth.  I  would no
however,  be  completely satisfied to report that M.
varians appears as a  true alkaliphil in  this country
until: (1)  many more massive occurrences have been
recorded with  accompanying water  quality data and
(2) many more populations  from acid streams and
rivers have been observed.

   Oligohalobe (salt content not necessary, able to sur-
vive to  about  5,000  ppm) — The  upper range  of
chloride  tolerance found from our surveys was some-
what lower than 5,000 ppm.

   Euryoxybiont (tolerant of  a wide range of  oxygen
content) — Table 2  shows presence at a rather wide
range of oxygen saturation.

   Beta-mesosaprobe (living in and indicative of the
pollution zone  in which ammonia compounds of the
fatty acids are found and in which further oxidation
takes place) — Until a more precise chemical  defini-
tion for this  zone can be made,  it is not possible to
decide how indicative this  species is of this zone.

   Saprophyte  (a diatom assuming  the function of  a
saprobiont, i.e., massive in polluted waters, appearing
as if restricted to this habitat) — Hustedt (1957) states
that M. varians, when appearing in massive amounts,
can be considered  a saprophyte, not necessarily be-
cause of a preference for this organically enriched
habitat,  but because of its  euryplastic nature (wide
tolerance range) coupled with the  disappearance of
other stenoplastic (narrowtolerance) species. Palmer
(1959) lists the alga as an indicator of polluted condi-
tions, but makes no mention of frequency as an indica-
tor.   Our data show appreciable NO3 content  when
frequencies over 15 percent are present.  In these
particular  cases the  total  diatom species numbers
were depressed.
   Eutrophic (waters  with  considerable  amounts of
nutrients) — Such a category is indicated by the data.
There may  be some correlation with this designation
and  Sovereign's 1958  statement that  he found M.
varians  rare in  the  mountains where waters  are
commonly oligotrophic and common in the lowlands
where mesotrophic  to eutrophic waters  are  much
more common.

   Current-indifferent   (no preference for fast- or
slow-flowing water) — Field observations of my  own
and habitat  designations for many collections of  this
species confirm this category.

   Eurythermal  — Temperature  ranges  are  broad
enough  that this  diatom can  be considered  eury-
thermal.

   Maximum development is considered by Scheele
(1952) to occur in  winter.  Liebmann  (1951)  and
Schroeder (1939) report a maximum in summer.  I
have  seen this  species  during all seasons, but  our
few high-frequency samples (collected in summer) are
insufficient  to label any particular season most suit-
able for maximum growth. In this case it is probable
that season  is  important as it applies to one river
system in one area, but  that generalizations applied
to large climatic and geographic areas are not mean-
ingful.

             Nitzschia amphibia  Grun.

   The data for this  and the remaining species were
taken in the  same manner as described for M. varians;
therefore, no further general comments need be made
regarding collection or presentation of data, Tables
3 and 4.

   Upper  ranges  for  sulphates  (511 ppm) and pho-
phates (ca.  8 ppm) are  considerably higher in  our
survey data than recorded by other authors.  On the
other hand, hardness figures (712 ppm) of other authors
exceed the upper range of our survey data.

   The spectrum is  again broad for this widespread
species in the  categories considered. The following
ecological terms have been used in connection with
N. amphibia.

   Alkaliphil —  All of the  larger populations of AT.
amphibia  were  found in waters with a  pH  above
7.0.   Only in the  less than 1 percent groupings  was
the range lower (pH  6.3). Our figures are in agree-
ment with this  category although the same comment
made  for  M.  varians  in  the  discussion of  pH is
applicable here.   Cholnoky (1962) claims  the  "opti-
mum" pH for this species is over 8.0.

   Oligohalobe — A chloride content of 1,470 ppm  was
recorded  when  this  species  was  present in  less
than  1  percent  of the samples in a collection from
the San Joaquin River.   The higher percentage  oc-
currences were in water with a chloride  content of
less than 300 ppm.

   Haloxene  (an accidental  guest,  a  "stranger" in
salty-water  communities) — Scheele (1952) prefers

-------
22
ENVIRONMENTAL REQUIREMENTS OF PLANKTON ALGAE
       Table 3. PHYSICO-CHEMICAL DATA (COMPUTER) FOR NITZSCHIA AMPHIBIA GRUN. (00141)
Factors
pH
Temperature, °C
Tl. hardness (as CaCOg), ppm
PO4, ppm
NO 3 (as N), ppm
NH3 (as N), ppm
Alkalinity (M. O.)
(as CaCOg), ppm
SiOo, ppm
Fe (soluble), ppm
Cl, ppm
804, ppm
Ranges
7.5 -
<12.0
<50.0
<0.001
<0.03
<0.001
<20.0

<3.0
<0.01
<3.0
<10.0
8.0to 8.0 - 9.0
to 30.0 - 35.0
to 500.0 - 1000.0
to 5.0 - 10.0
to 3.0 - 7.0
to 10.0 - 20.0
to 200.0 - 550.0

to 12.0 - 48.0
to 0.4 - 0.7
to 500.0 - 2500.0
to 240.0 - 480.0
No. of samples
02
80
82
79
81
81
82

72
37
82
71
  Table 4. PERCENTAGE FREQUENCY OF PHYSICO-CHEMICAL DATA FOR NITZSCHIA AMPHIBIA GRUN.

Frequency,
percentage
<1
1
2
3
7
10
11
Range
Literature


Frequency,
percentage
<1
1
2
3
7
10
11
Range
Literature


No. of
samples
35
2
3
4
1
2
1




No. of
samples
35
2
3
4
1
2
1





pH
6.3-8.4
7.5-7.8
7.4-7.7
7.5-8.0
7.4
7.5-7.7
7.3
6.3-8.4
2.0 - 9.0

Temp.,
°C
10-36
22-26
22-28
25-30
26
26-27
28
10-36
2-40

Hardness (as
CaC03), ppm
57-416
93-168
65-166
64-269
172
161-165
405
57-416
35-712

P04,
ppm
.004-2.7
.092
.133-. 290
.035-. 482
--
.20- .51
7.98
.004-7.98
.060

N03,
ppm N
0-4.9
0-.83
.080-1.58
.018-. 47
.03
1.41-1.52
.508
0-1.58
23-170

NH3,
ppm N
0-4.9
0-.03
.022-1.25
.018-. 50
0.03
.025-. 042
.181
0-4.9
--
Alkalinity
(M. O.) (as
CaCOg), ppm
21-243
64
49-70
66-193
—
49-51
177
21-243
10-750

Specific
conductivity
mho
1.4-8.6xlQ-4
l.SxlO"4
1.4-4.6xKT4
1.7-5.9xlO-4
	
4.4-4.5xlO"4
	
1.4-8.6xlO~4
2xlO-5-2xlO-4


Si02,
ppm
0.7-12.9
0.6-7.9
2.3-9.3
0.6-7.2
0.6
9.5-9.8
__
0.6-12.9
0.4-6.0


Fe,
ppm
<0.001-0.39
0.001-0.01
<0.001-0.54
0.0-0.09
0.00
<0.002
0.044
0.0-0.54
Total
0.4-MO

ci,
ppm
6-1470
6-56
11-14
10-23
50
17-21
94
6-1470
13-2000


so4,
ppm
20-511
23-25
155
40-152
63
149-160
290
20-511
5-6


DO,
%sat.
40-100
90-100+
80-92
50-82
84
80-90
100
40-100
0-100

 to  call it indifferent  to  slight salt  concentrations
 rather  than  haloxene.  Whatever the  case, and the
 choice  would be difficult, this species is recorded
 here only in very  low frequencies where salt con-
 centrations are above 100  ppm.

   Mesooxybiont  (tolerant of intermediate  concentra-
 tions of  oxygen) — We have  observed this species
 where  oxygen concentrations are between  40 and
 100 percent of saturation.   Data of  Foged (1948),
 however,   indicate  minimum   range  occurrence at
                               0 percent oxygen, which would place it in the cate-
                               gory of euryoxybiont.
                                  Beta-mesosaprobe—We have  no correlative ob-
                               servations on  large populations (above  11  percent)
                               of  this  species  with water  quality.   The ranges
                               available  do indicate presence in waters containing
                               relatively large amounts of NO3, PO4, and in lesser
                               amounts of oxygen.

                                  Current-indifferent — This diatom has also been
                               collected  in both fast and slow water in this country.
                                                                                                PO 816-361—2

-------
                             Diatoms and Their Physico-Chemical Environment
                                                      23
   Euryzonous (occurring at various altitudes) — Chol-
noky  and others object to the  use of altitude as an
ecological  factor  important in diatom distribution.
It  is  true  that most mountain  streams  are oligo-
trophic and most lowland streams are mesotrophic
to  eutrophic, aspects  of which may  call forth different
biological  expressions not relating to height above
sea level.   Nevertheless,  we should be careful about
discarding  altitude altogether as a factor unless we
wish to ignore pressure, light intensity and quality,
differences in  gas exchange,  etc.,  as contributing
factors.  The situation with pH may well be analogous
to  altitude.  In many instances the well-used factor
of  pH  is probably only important  as  it affects other
critical physico-chemical aspects of the environment.

   Another factor not commonly mentioned for diatom
species is  that of light.  This species is  considered
      in the Jukskei River) is a sign of "unstable" condi-
      tions.   He also considers that it can be frequently
      associated with an increase in nitrogen content when
      it occurs  in large numbers.


         Our figures  show it did  occur  once  at  an ap-
      preciably high NC>3 concentration (Table 6).  Hustedt
      (1937) found it  "massive" in 21 of 108 samples and
      states that whenever it  occurs in masses it is to be
      considered as beta-mesosaprobic.
         "Maximum" development is recorded by Bourrelly
      and  Manguin  (1952)  at a pH of  6.0  to 7.5 and by
      Hustedt  (1937) at a pH of 7.0 to 7.5.  The pH range
      of our higher frequencies was well above 7.0.
      Hustedt's data would indicate that  this species is an
     Table 5. PHYSICO-CHEMICAL DATA (COMPUTER) FOR NAVICULA CONFERVACEA KUTZ. (00104)
          Factors
        Ranges
No. of samples
          PH
          Temperature, °C
          Tl. hardness (as CaCOg), ppm
          PO4, ppm
          NO3   (as N), ppm
          NH3   (as N), ppm
          Alkalinity (M. O.)
             (as CaCOo), ppm
             2, ppm
          Fe (soluble), ppm
          Cl, ppm
          SO4, ppm
<7.5   to 8.0-9.0
<17.0  to 28.0 - 35.0
<50    to 500 - 1000
<0.001 to 0.5 -  5.0
<0.013 to 0.7 -  1.5
<0.009 to 1.0 -  10.0
<10.0  to 100.0 - 200.0

<6.0   to 6.0 -  48.0
<0.01  to 1.0 -  5.0
<3.0   to 2500 - 10,000
<10.0  to 480 - 960
      36
      30
      35
      34
      35
      35
      35

      35
      31
      35
      35
by Scheele (1952) (1954) and Hustedt (1937) as charac-
teristic  of the dysphotic zone.  This is probably to
say  that it  is  found under  a wide  range of light
intensities  and has  a low compensation point, since
we  have often found  it on substrates in clear water
near the  surface.  Scheele (1954)  has also reported
it from surface samples.

            Navicula confervacea Kiltz.
   There are fewer comparative data for this species
than for the first two diatom species (Table 5).  Like-
wise, our own samples are fewer. For some chemicals
no ranges of tolerance were found  in the literature
used.

   The  one high-frequency occurrence was from a
tributary of the Savannah River,  Lower Three-Runs
Creek.   This is a rather well-aerated,  dystrophic,
soft-water  stream  with very little organic material
and a moderate to swift current.

   Cholnoky (1958a) (1960) considers  this diatom to
be an indicator  of "succession," one which can with-
stand gross changes  in nitrogen content.  He  states
that  its frequent occurrence (usually in  association
with Gomphonema parvulum and Navicula seminulum
      alkaliphil.  Bourrelly and Manguin's data would cast
      doubt  on this designation.   Perhaps it would better
      be classified as indifferent.
         With  respect to temperature this  diatom should
      be considered as eury thermal.
                  Cymbella tumida (Breb.) V.H.

         Computer analysis ranges for this taxon are given
      in Table 7, and selected frequency ranges are found
      in  Table  8.    Relatively  broad  ranges again  are
      indicated for most factors.  This is  also indicated
      by  the  available  data from the literature.   Several
      ranges  are  recorded here  for individual chemical
      factors not found in other reports.
         High  frequencies  of this species  have  not been
      recorded by  us from streams and  rivers  in this
      country  where the chemistry of the water has been
      taken.   It does occur sometimes in large  numbers
      in  an individual  collection,  but it has not  been ob-
      served in great amounts throughout a large area of
      any river section investigated so far.  Scheele  (1952)
      also  found  it  only infrequently in the Fulda River.
      Since  it is  a large cell its presence in smaller per-
      centages may be  of greater significance than is true
      of the smaller  species in reflecting conditions of the
      biotope  (cf., Hustedt,  1957, p. 187). Other comments
      applicable to this species follow.

-------
 24
ENVIRONMENTAL REQUIREMENTS OF PLANKTON ALGAE
Table 6. PERCENTAGE FREQUENCY OF PHYSICO-CHEMICAL DATA FOR NAVICULA CONFERVACEA KUTZ.
Frequency,
percentage
<1
2
6
13
38
Range
Literature
No. of
samples
11
1
1
1
1

PH
6.3-8.3
7.7-8.4
7.8
7.5
7.3
6.3-8.4
4.0-8.2
Temp.,
°C
8-36
26-34
30
26
22
8-36
15-40
Hardness (as
CaC03), ppm
65-387
91-105
184
165
41
41-387
P04,
ppm
0.002-2.06
0.047-0.216
0.191
0.212
0.058
0.002-2.06
N03,
ppm N
0.022-2.81
0.234-0.357
0.470
1.410
0.146
0.022-2.81
NH3,
ppm N
<0.001-0.62
0.018-0.102
0.270
0.025
__
0.001-0.62
Alkalinity
(M. O.) (as
CaCO3), ppm
2-200
93-103
77
49
	
2-200
10-750

Frequency,
percentage
<1
2
6
13
38
Range

No. of
samples
11
1
1
1
1

Specific
conductivity
mho
1.39-5.8x10-4
2.72-3. 46xlO~4
5.8xlO-4
4.5xlO-4
8.7xlO~5
8.7xlO-5-5.8xlO-4

Si02,
ppm
3.0-12.7
5.5
7.2
9.5
11.1
3.0-12.7

Fe,
ppm
0.001-0.089
	
<0.002
<0.002
0.116
0.001-0.116

ci,
ppm
11-180
130-146
27
17
5
5-180

so4,
ppm
20-260
33-53
140
149
1
1-260

DO,
%sat.
40-100

80
90
85
40-100
    Table 7. PHYSICO-CHEMICAL DATA (COMPUTER) FOR CYMBELLA TUMIDA (BREB.) V. H. (00051)
Factors
PH
Temperature, °C
Tl. hardness (as CaCOo), ppm
P04
NO, # (as N), ppm
NH3 # (as N), ppm
Alkalinity (M. O.)
(as CaCO3), ppm
SiOo, ppm
Fe (soluble), ppm
Cl, ppm
SO4, ppm
Ranges
7.5 -
<12.0
<50.0
<0.005
<0.007
<0.001
<30.0

<3.0
<0.01
<0.5
<10.0
8.0to 8.0- 9.0
to 30.0 - 35.0
to 1000 - 5000
to 0.5 - 5.0
to 0.7 - 1.5
to 1.0 - 10.0
to 150.0 - 550.0

to 12.0 - 48.0
to 0.4 - 0.7
to 2500 - 10,000
to 90 - 240
No. of samples
65
64
65
65
64
64
65

59
46
65
58
             Table 8. PERCENTAGE FREQUENCY OF PHYSICO-CHEMICAL DATA FOR
                            CYMBELLA TUMIDA (BREB.) V. H.
Frequency,
percentage
<1
3
4
8
Range
Literature
No. of
samples
9
3
1
1

PH
7.3-8.4
7.4
7.6
7.8
7.3-8.4
4.0-8.5
Temp.,
°C
20-29
26-27
26
26
20-29
15-35
Hardness (as
CaCOg), ppm
77-159
117-176
166
168
77-176
144-712
P04,
ppm
0.009-0.304
__
--
--
0.009-0.304
N03,
ppm N
0.194-0.746
0.00-0.03
00
00
0.00-0.746
NH3,
ppm N

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                            Diatoms and Their Physico-Chemical Environment
                                               25
                 Table 8. PERCENTAGE FREQUENCY OF PHYSICO-CHEMICAL DATA FOR
                            CYMBELLA TUMIDA (BREB.) V. H. (CONTINUED)

Frequency,
percentage
<1
3
4
8
Range
Literature

No. of
samples
9
3
1
1


Specific
conductivity
mho
1.7-3. 7xlO"4
—
—
__
1.7-3.7xlO-4
--

Si02,
ppm
5.0-8.0
0.6-0.7
0.7
0.6
5.0-8.0
--

Fe,
ppm
0.0-.013
0.0-.04
0.0
0.01
0.0-.04
--

Cl,
ppm
6-146
32-50
56
56
6-146
22-2000

so4,
ppm
22-55
57-63
24
23
22-63
--

DO,
% Sat.
93-100+
80-84
88
90
80-100+
—
   Alkalibiont —Foged (1948)  considers the  species
as  such but with the recorded pH  range of 6.5 to
8.3 given by him it  would either have to be an alka-
liphil or a pH-indifferent species,  if one considered
the term alkalibiont in  its  strict sense.   Hustedt
(1957)  lists  it as pH-indifferent.   We  have no re-
corded ranges below pH 7 for this species.
   Oligohalobe — Although the computer analysis re-
cords  chlorides  up to a  value above  2500 ppm, the
selected frequency data show very low chloride read-
ings.   Foged's records at 200 ppm show occurrence
of the diatom as "rare."
   Oligosaprobe — Although  so  listed by  Hustedt
(1957), he remarks that the more frequent occurrence
on rotting plants in the vicinity of sewage influxes
points  to a preference for more markedly eutrophic
habitats.
   Current-indifferent — Foged (1948) considers the
species as  such.   I have  also observed it both in
fast-flowing water  and  in more  quiet  back-water
areas.
           Navicula ingenua Hust.

   This diatom was  identified from this country for
the first time in 1958 by Dr. L. G. Livingston of our
laboratories.  The species  was found in a collection
series from the Tennessee River made  in October
of that year.   The  growth was  principally  on log
surfaces,  sometimes  intermixed  with growths of  a
fresh-water sponge.

   Later,  in  June  1960,  it was recorded  in smaller
numbers in  the Savannah River.  In the  fall of the
same  year  another  collection  from Lower  Three
Runs Creek  also  contained  a small  number of this
diatom species.

   Chemically, the waters in which this species was
found  are  similar,  as  Table 9  shows.   Nitrogen
compounds and alkalinity were slightly higher in the
Tennessee  River.  Silicon was higher  in the Savannah
River, but  no importance can be  attached to this at
present.   All three areas  at the time of collection
showed the following water quality: soft, very low in
chlorides, well aerated with moderate to low nitrogen
and phosphorus levels, moderately buff ered, low levels
of  sulfate,  and a pH not  strongly  deviating  from
neutral.
                  Table 9. PHYSICO-CHEMICAL DATA FOR NAVICULA INGENUA HUST.

pH
Temperature C
Tl. hardness (as CaCO3), ppm
PO4, ppm
NO3, (as N), ppm
NHg, (as N), ppm
Alkalinity (M. O.)
(as CaCO3), ppm
Specific conductivity
SiO2, ppm
Fe (soluble), ppm
Cl, ppm
S04, ppm
Dissolved oxygen, %
Tennessee
Sta. 2 (21%)a
7.5
22
65-68
0.185
0.380-0.180
0.580
68-69
1.7xlQ-4
2.3
0.36
10
—
82
Sta. 3 (3%)
7.7
22
64-66
0.145
0.100-0.040
0.500
66-68
1.7xlO'4
1.9
0.09
10
--
82
South Carolina
S. R. «1%)
6.8
24
19
0.15
0.207
<0.001
18
6.5xlO~5
14.6
0.72
7
8
83
L3R«1%)
6.8
25
37
0.092
0.118
0.047
6
l.OxlO'5
6.2
0.53
6
10
70
   Percentage occurrence of species.

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26
ENVIRONMENTAL REQUIREMENTS OF PLANKTON ALGAE
           DISCUSSION AND SUMMARY

   The foregoing information has given some chemi-
cal ranges of tolerance of the five species considered.
Some attempt has been made to qualify the species
presence  and record the chemical  characteristics
of the waters at given percentage levels.

   These  figures  in  no way are intended to reflect
the true  range for any particular chemical.  When
one considers all the possibilities for chemical and
biotic interaction, it is truly amazing that any general
patterns emerge at all.

   Of  the common species discussed here, mere
presence  appears to have no  direct relationship to
water  quality changes, at least to those measured.
Occurrence in relatively large amounts does  show
frequent  agreement with ecological destinations of
others.    However,   such small  numbers  of high-
frequency occurrences,  both  in  this  study and in
others, are only  additive and do not yet fix physico-
chemical  boundaries except in a general way.

   To use quantity as an indicative factor poses some
problems.  First is the difficulty of knowing what is
meant by  "best development." Does this mean simply
frequent recurrence of the species under given ranges
of conditions?

   Niessen, for  example, gives the following data for
Nitzschia amphibia collected in: 3 samples at  a pH
of 3.5 to  5; 4 samples at 5 to 6; 23 samples at 6 to 7;
29 samples at 7  to 8.5; 2 samples at over 8.5.  For
the same  species Hustedt gives:  1 sample at a pH
of  2  to  3; 1 sample at 3 to 4; 6 samples at 4 to 5;
10 samples at  5 to  6; 25  samples at 6 to 7; 177
samples at 7 to  8; 199 samples  at over 8.0.  Based
on these  figures N.  amphibia  would be considered
an alkaliphil species.  It has, to be sure, been found
by various workers including myself in alkaliphilous
situations and commonly so,  but mere totaling of
occurrences without knowing whether equal numbers
of samples were made under acid conditions or what
the  year-round  picture is cannot  lead to definite
conclusions.

   Perhaps "best development" means occurrence in
great numbers.   This is fine except that it is some-
times  difficult to know just when a species can be
called "dominant," "massive," or "quite common."
Use of a  cell counting  technique, although it too has
its shortcomings, seems to be somewhat  more de-
sirable than an estimation of frequency,  even though
this estimation is based on several samples from the
same habitat (Scheele, 1952).

   In most rivers and streams in this country,  com-
posited collections from both  unpolluted and rather
polluted areas seem to  yield  about the same cell
size diversities.  Thus percentages of a given species
related to a mixed-size population should equate
fairly well.

   The information presented  here in  the  tables for
M. varians  indicates that  about 20 to  40 percent
frequency may be  high  enough  by our method to
                                consider the  diatom "present in large numbers" and
                                thus some  measure or indication of organic enrich-
                                ment  or pollution,  since  the  nitrogen  content  was
                                higher at the  high-percentage occurrences. However,
                                the  presence of  high amounts  of nitrogen does not
                                always  indicate  large  populations of  M. varians.

                                  There was a  less than 1  percent  occurrence of
                                this  species  in  the  Ottawa River  at NOg and NHg
                                amounts of nearly  5 ppm.   At a different location
                                in the same  river, the species also had a less than
                                1 percent frequency at an NHg concentration of 43.4
                                ppm.   In the  former case,  with 5-ppm concentrations
                                of NOg and NHg, there was a high incidence of other
                                species.  Navicula  sp.  accounted for 30 percent of
                                the  total population, Nitzschia intermedia Hantz. for
                                15 percent, and  AT. palea (Kiitz.) W. Sm., 13 percent.
                                The total species  present  six or more times was 36,
                                a depressed  figure for this  river section.  At the
                                second  location in  the Ottawa River where the NHg
                                concentration was over 43 ppm, AT. intermedia repre-
                                sented  43  percent and  N. palea  25  percent of the
                                total population.  Total  species present six or more
                                times were reduced to 19.
                                   This would indicate that certain species do gain
                                ascendancy in situations with high nitrogen content,
                                but, depending on the available population, the species
                                may be different.   This may  point  to further selec-
                                tivity under conditions of organic enrichment.

                                  It would seem advisable to continue our attempts
                                to learn what major imbalances or changes in water
                                quality  actually  call forth in the way of dominancy
                                of individual  species, but to accompany these obser-
                                vations with  a  clear look at the entire population
                                structure,  according  to species  diversity as  pro-
                                posed  by Patrick  (1949)  and Patrick et al.  (1954),
                                as an  equally important and very necessary part of
                                any major change in water  quality.

                                   Further,  we  need to know  more about the con-
                                tinuous developmental cycle of individual rivers, the
                                taxonomy  of the  inhabiting flora and  fauna, their
                                fluctuations throughout the year,  and their reactions
                                to constant  change in physico-chemical  factors of
                                the  river.

                                   As Fjerdingstad (1950) andCholnoky (1960) suggest,
                                the  magnitude and  rapidity of fluctuations may be as
                                important  as the  maximum - minimum  recordings.

                                   Fjerdingstad (1950) states (p. 100) . . ? diatoms ...
                                seem on the  whole to be much more sensitive to  poi-
                                sons than the Cyanophyceae.  This is an added reason
                                for   not regarding  the  individual diatoms as  very
                                suitable indicators  of  pollution,  especially of  the
                                order   alpha-mesosaprobic and  polysaprobic"  . .  .
                                This  would  only  seem  to add  support to the use of
                                diatom diversity  as an indicator  of altered water
                                quality,  as  proposed  by   Patrick  et  al.   (1954).

                                   This  is likewise  in  line with  a remark made by
                                Hustedt (1957, p.  196).  He says that the number of
                                saprobic situations in which diatoms develop in great
                                masses is not great, this zone being more character-
                                ized  by a negative  factor,  i.e., the  absence of the
                                other species characteristic for that water but which
                                are more oxygen-stenoplastic.

-------
                            Diatoms and Their Physico-Chemical Environment
                                               27
  Of  the factors  considered,  the most frequently
reported for diatoms are pH, temperature, and, to
a lesser extent, categories of pollution.

   The  pH  has been considered as one of the most
important factors which correlate  with diatom oc-
currences  (Hustedt,  1939, 1956).   Cholnoky  (1960)
emphasizes that the  magnitude of pH fluctuations
is of  prime importance  and, in this connection, that
the  buffering capacity should  always be considered,
since   weakly buffered  waters  have very  different
diatoms  than  strongly buffered waters at the same
general pH.

   The  matter of "optimum growth  range" or "best
development" cannot be  decided on  data from a few
mass  populations.   The data we  have on  greater
frequencies do  show pH, temperature,  and other
water quality ranges in  general agreement with the
statements made by others, but, until large numbers
of a  species  in  question are  observed many more
times under the conditions we suppose represent its
range of greatest growth, we will do well to use these
key-word physico-chemical  categories  with some
caution.

   For purposes of indicating a certain level of water
quality  in a river, it may become an academic ques-
tion as to what the reasons are for the overdominance
of a single species or a  few species, that is,  whether
the  diatom species is just "living alone and has had
room to spread out," or whether it is really thriving
under  optimal   conditions.   Nevertheless  I  would
suggest that the terms "optimum growth conditions"
or "range  of most suitable growth" be replaced by
some such statement as "range  of greatest growth"
or better still by a relative frequency range.

   Temperature ranges are broad for the four com-
mon species considered.   Few stenothermal species
have been reported, the term eurythermal being more
applicable  to  the  great  bulk  of  diatom species.

   Of the four more commonly occur ring diatoms dis-
cussed  C.  tumida  appears less  clearly  associated
with  organic pollution.    Our  data  indicate  it  can
tolerate  elevation in  nitrogen content, but we have
no evidence that would indicate it appears in larger
numbers under higher nitrogen concentrations.

   The  exact role  that Melosira  varians, Navicula
confervacea, and Nitzschia amphibia may  play  as
indicators of pollution  is not yet clear. They are all
reported to be variously involved with the presence
of elevated nitrogen content.   They have been ob-
served  in  larger numbers than  usual when organic
enrichment  and  moderate to  heavy pollution  are
present.   On the other hand,  even though organic
pollution is present the diatom may be present only
in very  small numbers.    In such cases, however,
their continued presence in small numbers could be
a function of the presence of another slightly more
tolerant species.

   It  is most probable that other diatom  species do
show much  narrower ranges of tolerance  and can be
more clearly categorized.   These more  widespread
species just discussed have wide ranges  of physico-
chemical tolerance, making their most efficient range
of growth much more difficult to establish.
                                             REFERENCES
Bourrelly,  P.  & E.  Manguin.  1952.  Algues d'eau
douce  de la Guadeloupe  et dependances recueillies
par la Mission P. Allorge en 1936. — Paris: Sedes.
282 p.

Cholnoky, B.J.  1958a.  Hydrobiologische Untersuch-
ungen in Transvaal II.  Selbstreinigung im Jukskei-
Crocodile Flusssystem. —  Hydrobiologia,  11(3/4):
205-266.

Cholnoky, B.J.  1958b.  Beitrag zu den Diatomeenas-
soziationen  des Sumpfes Olifantsvlei  sudwestlich
Johannesburg. — Ber. Deutschen  Bot. Gesell., 71(4):
177-187.

Cholnoky, B.J.  I960.   In  Harrison,  A. D., P. Keller,
&  D. Dimovic.   Ecological studies on Olifantsvlei,
near  Johannesburg;  with notes on  the  diatoms  by
B.  J.  Cholnoky.  — Hydrobiologia,  15(1/2): 89-134.

Cholnoky, B.J.  1960.  The relationship between algae
and the chemistry of natural waters. — Counc. Sci.
Industr.  Res. Reprint  R.W. No.  129,  p.  215-225.

Cholnoky,  B.J.  1962.  Beitrage  zur Kenntnis  der
Okologie der Diatomeen in Ost-Transvaal. — Hydro-
biologia, 19(1):  57-119.
Fjerdingstad,  E.  1950.   The microfauna of the river
Nfyilleaa; With special  reference to the relation of
the benthal algae to pollution.   —  Folia  Limnol.
Scandinavica, No. 5,  123 p.

Foged, N. 1948. Diatoms in water-courses in Funen.
VI. Conclusions and general remarks. — Dansk Bot.
Ark., 12 (12): 1-110.
Foged, N.  1949.  Diatoms in the salt bog of Lange-
mose in East Funen. -- Dansk Bot. Ark., 13(6): 1-31.

Foged,  N.  1951  (1955).  The diatom flora of some
Danish  springs.    Part  1.  —  Natura Jutlandica,
4, 84 p.
Foged,  N.  1953! Diatoms from  West Greenland. —
Medd. on Gr^nland, 147(10), 86 p.

Hustedt,  F. 1937.   Systematische  und okologische
Untersuchungen uber die Diatomeen-Flora von Java,
Bali und  Sumatra.  --  Arch. f. Hydrobiol.   Suppl.,
15(1): 131-177; 15(2): 187-295.

Hustedt,  F. 1938a.   Systematische und okologische
Untersuchungen uber die Diatomeen-Flora von Java,
Bali  und  Sumatra.  --  Arch.  f.  Hydrobiol. Suppl.,
15(3): 393-506; 15(4): 638-790.

-------
28
  ENVIRONMENTAL REQUIREMENTS OF PLANKTON ALGAE
Hustedt,  F.  1938b.   Systematische und okologische
untersuchvingen  iiber die  Diatomeen-Flora von Java,
Bali und  Sumatra.   — Arch.  f. Hydrobiol.   Suppl.,
16(1): 1-155.

Hustedt,  F.  1939.   Systematische  und okologische
Untersuchungen  liber die  Diatomeen-Flora von Java,
Bali und  Sumatra.  —  Arch.  f. Hydrobiol.   Suppl.,
16(2): 274-381.

Hustedt,  F. 1942.   Susswasser-Diatomeen des indo-
malayischen Archipels  und der  Hawaii-Inseln.  —
Internat. Rev. Ges. Hydrobiol.,  42: 1-252.

Hustedt, F.  1943.  Die Diatomeenflora einiger Hochge-
birgsseen  der Landschaft Davos  in  den Schweizer
Alpen. — Internat. Rev. Ges. Hydrobiol., 43:225-280.

Hustedt,  F. 1956.  Kieselalgen  (Diatomeen). — Stutt-
gart:  Kosmos Verlag. 70  p.

Hustedt,  F.  1957.    Die  Diatomeenflora des  Fluss-
systems  der Weser im Gebiet der Hansestadt Bre-
men.  —  Abh. Naturw. Ver.  Bremen,  34(3): 181-440.

Hustedt,  F.  1959.    Die  Diatomeenflora der  Unter-
weser von der Lesummundung bis Bremerhaven mit
Beriicksichtigung des UnterlaufsderHunteundGeeste.
—  Veroff.   Inst.  Meeresforsch.   Bremerhaven,  6:
13-176.

Kolbe, R. W. 1927.   Zur Okologie, Morphologic und
Systematik  der  Brakwasser-Diatomeen; Die Kiesel-
algen  des  Sperenberger  Salzgebiets.  —  Pflanzen-
forschung, Heft 7,  146 p.
Kolkwitz, R.  1914.
G. Fischer.
Pflanzenphysiologie. —  Jena:
Kolkwitz,  R.  1950.   Oekologie der  Saprobien.  —
Schriftenr.  Ver.  f. Boden  u.  Lufthygiene,  No. 4,
64 p.

Kolkwitz, R.  &  M. Marsson.  1908.  Okologie der
pflanzlichen Saprobien. — Ber. Deutschen Bot. Gesell.,
26a: 505-519.

Liebmann,  H.  1951.   Handbuch der Frischwasser-
und  Abwasser-biologie.  —  Munchen:   Verlag R.
Oldenbourg.  Vol. 1, 539 p.
Niessen, Herta. 1956.  Okologische Untersuchungen
uber die Diatomeen und Desmidiaceen des Murnauer
Moores. —  Arch.  f.  Hydrobiol.,  51(3):  281-375.

Palmer, C. M. 1957.  Algae as biological indicators
of  pollution.   In  C. M.  Tarzwell,  ed., Biological
Problems in Water  Pollution.  —  U.S. Dept. Health,
Educ.  and  Welfare, Robt.  A.  Taft  Sanit.  Engng.
Center, Cincinnati, Ohio, p. 60-69.

Palmer, C.  M. 1959.  Algae  in  water  supplies; An
illustrated manual on the identification,  significance,
and control  of  algae  in water  supplies.  — U.S.
Public  Health  Service  Publ.  No.  657.   Washington:
Government Printing Office. 96 p.

Patrick, Ruth.  1949. A proposed  biological measure
of  stream  conditions,  based  on a survey of the
Conestoga  Basin,  Lancaster  County,  Pennsylvania.
—  Proc. Acad. Nat. Sci. Philadelphia,  101:277-341.

Patrick, Ruth & L.R. Freese. 1961.  Diatoms (Bacil-
lariophyceae) from  Northern  Alaska. — Proc. Acad.
Nat. Sci. Philadelphia, 112 (6):  129-293.

Patrick, Ruth, M.H. Holm, &  J.  H. Wallace.  1954.
A new method for determining  the pattern  of the
diatom flora.  —  Not.  Nat.  Acad.  Nat. Sci. Phila-
delphia, No. 259, 12 p.

Peter sen,  J. B. 1943.  Some halobion  spectra (dia-
toms).  — Det Kgl.  Danske   Videnskab.   Selskab
Biol. Meddel., 17(9): 95 p.

Scheele, M.  1952.   Systematisch-Skologische Unter-
suchungen  liber die Diatomeenflora der  Fulda. —
Arch. f. Hydrobiol., 46: 305-423.

Scheele, M.  1954.   Die  Diatomeenflora der Schle-
usenwande in  der  unteren Funda und  die Lichtab-
hangigkeit  einiger Diatomeenarten.   —  Arch. f.
Hydrobiol., 49(4):  581-589.

Schroeder,  H.  1939.   Die  Algenflora der  Mulde;
Ein Beitrag  zur  Biologie  saprober  Flusse.
Pflanzenforschung, Heft 21, 88  p.

Sovereign, H. E.  1958. The  diatoms of Crater Lake,
Oregon. —  Trans. American  Micr.  Soc.,  77(2):
96-134.

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                     The Application of Diatom Ecology to Water Pollution and Purification
                                                                                              29
                   THE APPLICATION OF DIATOM ECOLOGY TO WATER POLLUTION

                                           AND PURIFICATION

                                              F.E. Round *
   Diatoms are the dominant plant organisms in many
natural habitats and as such are subtle indicators of
the environmental  conditions, whilst they themselves
modify the habitat.

   In an aquatic habitat the micro-organisms occur as
a film over all the surfaces and also as a suspension
(plankton); the water  flows over  and through this
"filter" of micro-organisms, affecting the composition
of the water and at the same time modifying the flora.
The  "self purification" of polluted waters is certainly
enhanced  by the growth of such  micro-organisms
amongst which the diatoms are prominent. The study
of the  interaction of the diatoms and the waters is a
most profitable and important  aspect that has perhaps
been somewhat neglected in favor of the relationship
between floras and degrees of pollution.  Neither can
be studied advantageously in isolation for they are
complementary  aspects of  a  biodynamic system.

   It is not  sufficient  for the algal ecologist to know
that  a  water is  polluted because it is chemically or
bacteriologically impure; an algal  index  of pollution
is necessary, which is not possible unless there is a
standard unpolluted flora to refer to.  The penetration
of diatoms into  polluted waters can then be related
to this standard and the whole  seen  in perspective.
The  standard can  only  be the  diatom flora of pure
natural water, the nearest approach to which in nature
is the  water of  cold springs that is usually alkaline,
nutrient  rich, organically  unpolluted,  and at almost
constant  low temperature (around  9°C.),  or  the
                                               collections of  rainwater in small bog pools on moor-
                                               lands  and heaths  that are of low  nutrient  status,
                                               highly acid but organically rich.  Both these waters
                                               exhibit a  highly  characteristic diatom  flora.  The
                                               former is basically the simplest since the constant
                                               flow provides new nutrients, carries away any extra-
                                               cellular and  decay products,  and may also prevent
                                               interaction between species, whilst the  latter is com-
                                               plicated by the accumulation of products of assimi-
                                               lation, etc. All other so-called unpolluted waters are
                                               complicated  by varying  degrees  of "pollution" by
                                               inorganic  and/or  organic  chemicals right through to
                                               the  extremes  of  sterility where  no diatoms exist.
                                               Water more acid than that of peat pools is probably
                                               found  only in regions receiving acid mine wastes,
                                               whereas waters more alkaline than that of cold springs
                                               are found naturally in many calcareous regions. From
                                               these two  types water passes through the well-known
                                               series to complete sterility or is maintained at some
                                               stage prior to this.

                                                 This  series can be found in running or standing
                                               waters, which  adds  a considerable problem  since
                                               distinct  floras  are found  in the two habitats  and a
                                               species may not have the same tolerance to pollution
                                               in each habitat. Although much is known about diatom
                                               species distribution, the data are mainly qualitative;
                                               although these data are of great value when indicator
                                               organisms are  considered, they are of less use for
                                               the majority of species that occur over a wide range
                                               of polluted conditions. On a quantitative, cell number
                                               basis, however, most species have a distinct optimum
ine waste waters
icreasing acidity
\



[Diatoms becoming! Natu
]_ scarce _| alka
Increas
TT A T FT A TMTRTP


ral highly
line waters
ing alkalinity


[Diatoms frequent

cold spring

                                             MESOSAPROBIC
       [Diatoms frequent]     Y -

       [Diatoms frequent]     B -

       [Diatoms frequent]     L -

[Few species, sometimes abundant] Y -I

[Few diatom species or absent]    B -}POLYSAPROBIC

[Few diatom species or absent]    L -)  \         /

       [Diatoms absent]               I  STERILE, COPROZONIC OR METAL TOXIC
* Department of Botany, University of Bristol, England.

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30
ENVIRONMENTAL REQUIREMENTS OF PLANKTON ALGAE
of growth dependent upon the habitat conditions; the
accumulation  of such data  is  necessary before any
species  can be used as an  indicator of the degree
of pollution.  Unfortunately very few detailed studies
have been made on any species in nature where it is
important that primary quantitative data be collected,
or in the laboratory where deductions  from studies
in the  natural habitat can be checked and the effects
related to the metabolism of the organism.  Three
further problems are superimposed on the ecological
approach:  first is  the  recognition of the individual
microhabitats; secondly, the sampling of these habitats;
and  thirdly, the clear  recognition of the degree of
pollution when the diatoms are being used as indicators.

   To  utilize  diatoms in pollution studies, it is nec-
essary to appreciate the range of habitats and the
discreteness of each  diatom  flora within its habitat;
otherwise, an impossibly large number of species can
be determined, e.g., some 615 species were recorded
by Hustedt (1957)in the polluted R.Weser (an indication
of the  tolerance of  diatoms to pollution, although only
17 species were classified as saprophytic). The details
of  diatom  floras  in microhabitats  are still  very
incompletely  known,  as  are  the tolerances of  each
species  to the  gross  habitat conditions  such  as
substrata, water flow, temperature, pH,  etc.  Since
diatoms  are siliceous organisms, attention  has  been
focused  on the supply  of  silicates in  the habitats
and relatively slight consideration has been given to the
organisms general  physiological requirements, meta-
bolic pathways,  extracellular products,  etc. Finally
the intricate nature of the siliceous cell wall has led
to an overwhelming concentration on their taxonomy.

   One of the simplest and best documented groups in-
volving diatoms is the phytoplankton community floating
in the  water.  It is, however, of little use in flowing
waters (Fjerdingstad, 1960; Patrick, 1957)exceptwhere
flow is reduced e .£. by tidal pressure or damming, or in
very large  slow-flowing rivers, since lenitic phyto-
plankton is merely a collection of casual species from
the  drainage  basin.   Hustedt  (1957) has been able
to trace the gradual  increase  in pollution  in the R.
Weser over the last 50 years from the diatom records.
The occurrence of Nitzschia acicularis,Staphanodiscus
hantzschii,  and  Melosira varians  is an  indication
of organic pollution ("Saprophytic species"); yet these
are  all common in waters which, although admittedly
rich in organic matter,  could not be termed polluted.
Both the Nitzschia and the Melosira species are also
extremely abundant  on sediments  and  are merely
another example of the accumulation of littoral species
in the  plankton under certain conditions.  Stephana-
discus is  a frequent diatom of waterworks storage
reservoirs and can hardly be an indicator of pollution.
On the other hand, the Weser in the region of Bremen
is polluted, and the list of planktonic species suggests
that the combination of large cell numbers of Cyclotella,
Stephana discus and Thalassiosira together with a large
number of species of Nitzschia is  characteristic of
this polluted  river.   Species  of  the above centric
genera are rarely  found, however, when submerged
                                slides are used.  A good example of lake phytoplankton
                                populations is  that reported by  Jarnefelt (1961) who
                                showed that pollution  of  a lake from  a small town
                                favored  the growth   of   Asterionella  gracillima,
                                Cyclotella stelligera,Fragilaria crotonensis, Melosira
                                granulata, M. islandica,   andSynedra   berolinensis,
                                whilst Rhizosolenia eriensis appeared only in samples
                                from the town polluted region and not at all in samples
                                from the purer lake waters above the  pollution or
                                below in the chemically polluted region. Other species
                                also  show  a  slight  enhancement  of growth  in this
                                region, and although it is true that "no species is
                                adapted  to  living  in polluted  conditions which are
                                the products of civilization and so very much younger
                                than  is any species" (Hynes, 1960), it is equally true
                                that  all  so-called natural populations  are  modified
                                to some extent by "organic pollution" from the moment
                                that heterotrophic, excretory organisms appear in the
                                habitat.

                                   Chemical pollution  by man-made  chemicals is
                                another matter.   The danger in Jarnefelt's analysis
                                is that species carried into more polluted areas are
                                still recorded although they may be dying off;* e.g.,
                                it seems unlikely thatFragilaria crotonensis is equally
                                adapted to the pollution from sulphite wastes in the
                                zone below the town whilst Rhizosolenia eriensis is
                                not.  The presence of the former in the samples and
                                the absence of the latter may merely reflect different
                                sedimentation rates, for in the  less polluted waters
                                below the zone of maximum pollution from sulphite,
                                in the  so-called  zone of  "intensive  photosynthetic
                                purification,"  Fragilaria  and other algae  are less
                                abundant. An alternative explanation is  that the  com-
                                bination of organic and chemical pollution allows some
                                of the organisms that are sensitive to  chemicals to
                                grow, whilst beyond this where the chemical pollution
                                is accompanied by decreasing organic pollution these
                                same organisms are eliminated. If this latter hypo-
                                thesis is  correct,  then experimentation with  com-
                                binations of  pollutants  may  lead  to  methods  for
                                enhancing  self-purification,  since  in   the zone of
                                sulphite  pollution no diatoms were characteristic or
                                achieved greater numbers than elsewhere.

                                   In many Swedish  rivers there is a characteristic
                                growth of  Frustulia rhomboides  and   Synedra ulna
                                below regions  of  sulphite discharge from wood pulp
                                factories.  F.  rhomboides is an acid-loving species,
                                which may  account  for   its  occurrence  in these
                                habitats,  but  it  also  has its  cells  embedded in
                                macilage that may act as a buffer between the medium
                                and  the  cell  (cf. Staurastrum  below).   In  S. Africa
                                it has been shown to be  present  at pH below 3.0 in
                                acid-polluted  streams.   This is a species common
                                on sediments,  coating stones and  water plants, etc.,
                                and it may prove to be the only true diatom component
                                of such waters since plankton is obviously not  adapted
                                to such conditions.

                                   The other freely  motile community  is that on the
                                sediments  (epipelic) of lakes,  ponds,  and  running
                                waters; only slight use has been made of it in pollution
   The movement of planktonic organisms does indeed render them less valuable as indicators of pollution, a fact pointed out
   by F|erdingstad (I960) leading him to devise a system in which benthic algae are used.

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                   The Application of Diatom Ecology to Water Pollution and Purification
                                                 31
studies, e.g. Gaspers &  Schultz (1962).  The flora is
often composed  largely  of diatoms  and can easily
be  sampled by removing a small amount of sediment,
placing this  in a petri dish,  pipetting off the excess
water,  and placing cover-glasses  on the moist mud
surface  (Round,  1953).  The  diatoms are phototactic
and quickly rise onto the undersurface of the cover-
glass, which can be removed and examined under the
microscope.   In  this way only the living species are
recorded;  methods  involving cleaned preparations
frequently give  a  false  impression  owing  to  con-
tamination by dead frustules from  other zones.  This
flora is very  sensitive  to changes  in  the habitat;
in organically polluted waters there is often a domi-
nance of Nitzschia  species; in waters polluted by salt
wastes,  a whole range of halophilic diatoms occur,
e.g., Caloneis amphisbaena,  Amphora spp., Amphi-
prora spp.,  Bacillaria paradoxa,  Nitzschia obtusa,
Cylindrotheca gracilis, etc.  In marine habitats pol-
lution affects this epipelic flora  by increasing the
flagellate count, especially Eutreptia spp., andfavour-
ing  Nitzschia spp.  almost to the exclusion of all
others.  The details of this community  in waters of
varying  degrees of pollution have  not been  fully
worked out,  and since  it  is  easy to sample and is
almost  always present it is worthy of greater study.
In the Weser, Hustedt (1957)  cites Melosira various,
Nitzschia co^nmunis, and Surirella ovata as abundant
saprophytic forms of the littoral  zone.   These are
abundant in many mesosaprobic streams  and rivers;
S.  ovata  in  particular  is tolerant  of  quite  high
salinities.  The epipelic flora is,  however, one that
may  be  eliminated  by  certain  types  of  pollution
simply  by covering with  wastes; e.g.  many streams
and rivers in industrial regions have a layer of coal
dust  over  the sediment.   When  conditions are  so
extreme, however,  as  to eliminate  this  flora by
physical means,  then few if any other algal species
will develop.

   The  attached  flora  has probably  received more
attention than  any other;  rarely, however, has the
actual flora  of rock or stone surfaces,  wood piles,
or aquatic plants  been investigated  although numerous
workers have pointed out the value that might result
from a study of  these habitats.   This flora like the
epipelic would yield valuable indicators of degrees
of pollution if a detailed study were made; for example,
abundant growths of Diatoma are found frequently
near  outfalls of  domestic  and farm sewage.   This
attached flora is the one  found  growing on  glass
slides,  etc., suspended in the polluted water; perhaps
because it is easy to observe, the natural habitats
have  been neglected.  The  slides are first colonized
by  bacteria  and  then followed by an  attached flora
often containing  a high  proportion  of diatoms, but
almost  certainly selective of those that can attach
to a smooth  surface.  The degree of growth and the
type of flora on  these artificial substrata have been
used  to indicate the  degree of pollution with  con-
siderable success, but one disadvantage is that the
sampling apparatus  must be  left  in  the water long
enough  for colonization and growth to occur on the
slides.   Instead  of waiting  for this, sampling of the
natural surfaces and of the  sediments  can give an
answer   within  24 hours.   The  claim  that  all the
species of the  water system will  sooner or later be
 found on the slides is undoubtedly true,  but  equally
 true is the fact that this method will yield no true
 picture  of the  flora of the microhabitats within the
 water and so there is little opportunity to accumulate
 the necessary  details of the diatom flora of actual
 microhabitats.   A detailed  quantitative  comparison
 of  the diatom  flora of glass slides and the natural
 attached communities is much to be desired.

    The use of  diatom indicator species  in pollution
 studies  may be  extremely  unreliable unless  other
 features  are also considered.  Since (organic) pol-
 lution in its milder stages often enhances the growth
 of  species it is necessary to determine the indicator
 species of this stage from  a detailed study of the
 diatoms of  each habitat  and to  compare the floras
 of  these habitats  with similar  but unpolluted  ones.
 This  use  of  indicators  tends to  be very  subtle;
 e.g.  the  enhanced growth of Asterionella, etc., in
 a Finnish  lake  quoted above.  The more advanced
 stages of pollution affect the balance of the  com-
 munities to a greater  extent, and finally so unbalance
 them that only one or a few species remain, which are
 able to grow to densities unknown in normal balanced
 systems.   Thus these indicators, which  they un-
 doubtedly  are,  can only be used when they are con-
 sidered in relation to the population as a whole.  Much
 confusion has arisen from listing indicator species that
 are merely components  of  a more or less  normal
 flora;  e.g.  Nitzschia palea is  abundant in  many
 habitats that would not rank as anything more than
 mesosaprobic; however,  its occurrence in abundance
 as  the sole  diatom is an indicator of polysaprobic
 conditions.   In a sense  all that is needed for an
 indication of pollution is the number of species in the
 habitat, for in all unbalanced ecosystems a single
 species or a few species remain and frequently grow
 abundantly.  This occurs in natural habitats of extreme
 type,  e.g., highly mineral waters.   It is probably
 true  that no diatom species  are confined to polluted
 waters since this is an unnatural state (cf. other groups
 of  organisms);  this  complicates the use of indicator
•species.  Diatoms can, however, be used as indicator
 species for certain ionic balances;  e.g.,  increase in
 salinity is readily detectable,  increase in calcium
 content  can also  be detected, and also increase in
 acidic  ions.  Detailed studies of  other species will
 undoubtedly reveal other useful indicators.

    Hustedt's study of  the  R. Weser showed that the
 detection of incipient pollution from a study of records
 is  feasible, but this requires long term observations
 that are rarely available  except on important water-
 ways  or  sources of supply for human  consumption.
 Since  diatom cell walls are relatively indestructible,
 however, they are preserved in  sediments of lakes
 and in the  littoral zone of the sea. The sedimentary
 material is  treated  in  the  normal way to  obtain
 slides for diatom analysis. Special sampling techniques
 are necessary to prevent disturbance of the cores and
 a fairly thorough  knowledge of the tolerance  of the
 species is required before the data can be interpreted.
 It is possible, however, to detect the time at which
 pollution started and any acceleration of the process.
 Normal floras do,  however, undergo cyclical changes
 of  varying degree, so  the  data  need  to be  treated
 cautiously.

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32
ENVIRONMENTAL REQUIREMENTS OF PLANKTON ALGAE
   The  effect  of  pollution  on  the metabolism of
diatoms is worthy  of serious consideration since it
may indirectly supply useful information on the range of
their metabolic processes.  It may be valuable also
to attempt to distinguish between the absence of nec-
essary nutrients or their unavailability in polluted
waters  and  the presence  of toxic compounds.  The
diatoms,  unlike  almost all  other plants, require a
source  of silica in addition to  the usual  carbon.
This  element is usually in adequate supply in natural
waters, but anything that prevents leaching of silicates
from soils or underwater sediments will prevent diatom
growth.   Thus  in some industrial disposal systems,
diatom  growth  may  be  completely prevented  by
blanketing of the  source  of silica  supply.  Apart
from availability  (and rarely  will  silica be un-
available  in  polluted  natural waters) there  is the
important aspect of its incorporation into the diatom
membrane; in this field there is almost no information
regarding mechanism or inhibitors.  Geissler (1958),
however,  showed that  the silica  wall has  a mem-
brane potential and will  absorb positively charged
particles  that  reduce  the motility  of Nitzschia, a
common genus in polluted waters.  It is an interesting
fact  that  in some habitats and often  in  polluted
waters  the  normally  motile  diatom species are
immobilized.  This may of  course affect the method
of sampling  outlined above.   The  uptake of silica is
an  aerobic process, dependent upon respiration and
almost certainly high energy phosphate.  Few diatoms
tolerate low oxygen concentrations. Thus, the absence
of almost all diatoms in polysaprobic water may be
due to the inability to assimilate silica at low oxygen
tensions.   Nitzschia appears to tolerate low oxygen
tension and  this may be the factor responsible for
its  abundance in mesosaprobic  waters and its pene-
tration into polysaprobic waters.

   Although  diatoms are  photosynthetic organisms
it has been known  for  some time (Lewin, 1935) that
they are  capable of assimilating  organic compounds
in  the dark.  To what extent they do this in natural
populations is  unknown, although there seems little
doubt that it must occur; polluted waters are the most
likely place  because  of the supply  of organic sub-
strates.  Diatoms may in fact effect some purification
by  utilization of these organic  compounds,  as for
example Chlamydomonas in sewage lagoons (Eppley &
Maciasr,  1962).    This also means that light is not
essential  for all diatoms and that in waters of high
turbidity due to pollution diatoms need not be lacking.
In  fact,  in turbid  littoral marine habitats  the rich
Nitzschia  flora on the segments probably lives at
very low light intensities; the author has found a very
rich diatom flora at 35 m. off the Pacific coast where
light intensity  is  less than 2  percent of  surface
illumination (Tailing, 1960). In unpolluted freshwaters,
however,  diatoms are not at all abundant below the
level to which approximately 5 percent of  the light
penetrates;  this suggests a  greater heterotrophic
tendency  in  the  marine  forms.   A study of diatom
depth distribution in polluted waters may be revealing.
Normal photosynthesis is only  likely to be limited
by lack of carbon dioxide or of metallic ions associated
with the pigments or processes. In addition metallic
ions  may inhibit this  assimilation.  Certain algae
can be adapted to concentrations of poisonous ions
                                (Cu and  Rb  ions)  and in some instances clones of
                                resistant types arise (Kellner, 1955).  To what extent
                                this happens  with diatoms is unknown.   Lund (1957)
                                showed that the diatom Asterionella contained large
                                amounts  of nickel (83Mg), lead (68Mg), titanium (1100
                                fig), and zinc  (1240 ;ug), whereas adismidStaurastrum
                                contained only 30,  10, 60 and 715 ng.  respectively
                                per gram dry weight.

                                   From a pollution aspect these data  suggest  that
                                certain diatoms may act advantageously in absorbing
                                harmful  ions, which would then be released  slowly
                                as the diatoms decayed. Marine species also absorb
                                ions in excess  of their  normal requirements.  In
                                effect this  is  part of the process of self purification
                                in all polluted waters,  and  thus anything done to in-
                                crease the algal  flora undoubtedly assists self puri-
                                fication.   The  same principle also operates in  the
                                absorption of radioactive wastes. Another point is that
                                some algae, e.g. the Staurastrum noted above, obviously
                                cannot absorb large quantities  of heavy metals; this
                                may be related to their extensive mucilage sheath,
                                which prevents penetration of the ions.  This in itself
                                is important  in  pollution since these  are the very
                                species that may be tolerant at least to mild inorganic
                                pollutions and are hence  to  be encouraged for their
                                contribution to oxygenation.   In view of  the tolerance
                                variability  of  different  strains  of diatoms to organic
                                factors  it  would  be surprising  if no  variation of
                                tolerance occurred in their inorganic nutrition. Only
                                isolation and experimental study of species with regard
                                to metallic ions will solve  this;  if diatoms  can be
                                found that  tolerate  certain metallic ions then these
                                may be  valuable  in purification of waters polluted
                                by inorganic  wastes.  Such species are most likely
                                to be found amongst the epipelic and attached diatom
                                flora, e.g. Nitzschia or Cocconeis species, and not
                                in the plankton where species  in general are more
                                sensitive,  e.g.  the  absence of  any characteristic
                                diatoms  in the sulphite pollution zone  in a Finnish
                                lake (Jarnefelt, 1961).

                                   Organic pollution may be more tractable since we
                                now know that some diatoms utilize organic molecules.
                                The  range of molecules utilized  and the number of
                                species tested experimentally, however, is  small.
                                Organic acids are  capable of being utilized provided
                                other conditions of the habitat are suitable. The effects
                                of aeration, temperature, pH control, etc., are worthy
                                of further  study in the  hope  that systems  can be
                                evolved that will facilitate heterotrophic diatom growth
                                and hence reduce pollution.

                                   The effect  of the diatoms on the polluted habitat
                                are at least threefold.   By absorbing nutrients  they
                                remove considerable quantities of chemicals from the
                                habitat; by their  photosynthesis  they oxygenate the
                                waters, which is one  of  the most important con-
                                tributions  to  the  system; and thirdly  they secrete
                                compounds that act  as antibiotics and sources of
                                organic matter probably of non-polluting nature.  The
                                latter feature  has recently  been demonstrated  with
                                cultures  of Nitzschia palea,  which in the light  only
                                produced  an  extracellular  substance  that  is anti-
                                bacterial to  E. coli  (Emeis, 1956).  Apart  from its
                                obvious value  in organically polluted waters where the
                                bacterial count is high, it is useful on slow sand filters

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                  The Application of Diatom Ecology to Water Pollution and Purification
                                                33
in waterworks and  on sewage beds.   Thus Emeis
(1956) found  that  water  when passed  through  an
experimental laboratory filter coated with Nitzschia
palea had  its  E. coli count reduced  by 50 percent.
Some  species  of  diatoms  produce  extracellular
capsules of  carbohydrate  nature and  all  diatoms
extrude mucilage to  some extent;  this diffuses into
the  medium and may complex with metallic ions.
                    SUMMARY

   A  more precise quantitative correlation  between
the composition of the diatom flora and the habitat
conditions is required.  A detailed study of the diatoms
in the aquatic microhabitats will almost certainly
reveal more reliable indicator species for the varying
degrees  of  pollution.   The tolerance of diatoms to
mixtures  of  pollutants and the frequent stimulation
of diatom growth by mold pollution requires experi-
mental  study,  which will probably yield important
fundamental data on diatom  nutrition.    Now that it
is clear from experimental work that diatoms utilize
organic compounds, absorb inorganic ions greatly in
excess of their requirements, and produce antibiotics
and  other  extracellular  products  it will be fruitful
to investigate these effects in polluted waters. Since
diatoms play an important part in  the purification of
sewage and of water supplies, it is probable that as
more is known about their biology, systems may be
designed  utilizing  diatoms  for the  breakdown of
pollutants.
                                              REFERENCES
Gaspers,  H.  &  Schultz,  H. (1962) Weitere  Uter-
lagen zur Priifung der  Saprobiensystems.  Int. Rev.
ges. Hydrobiol. 47, 100-117.


Emeis,  C.C. (1956).  Untersuchungen tiber die anti-
bakeriellen Eigenschaften der Algen. Arch, f. Hygiene,
140, 597-604.

Eppley, R. W. & Maciasr, F.M. (1962).  Rapid growth
of sewage lagoon Chlamydomonas with acetate. Physiol.
Plant. 15, 72-79.


Fjerdingstad,  E.  (1960).    Forurening  of vandlob
biologisk bedomt. Nordisk Hyg. Tidskr. XLI, 149-296.

Geissler, V. (1958).  Das Membran einiger Diatomeen
und seine Bedeutung  fur die lebende Kieselalgenzelle.
Mikroscopie 13.


Hustedt, F.  (1957).  Die diatomeenflora des Flussy-
stems der Weser im Gebiet  der Hansestadt Bremen.
Abh. naturw. Ver. Bremem 34, 181-440.

Hynes,  H.B.N. (1960) The biology of polluted waters.
Liverpool University Press.
Jarnefelt, H. (1961). DieEinwirkungder Sulfitablaugen
auf das Planktonbild.  Verh. Internat. Verein. Limnol.
XIV, 1057-1662.

Kellner,  K.  (1955).  Die adaptation  von Ankistro-
desmust  brawnii  an Rubidium  und  Kupfer.  Biol.
Zentralbl. 74, 662-691.

Lewin, J. C.  (1953). Heterotrophy inDiatoms. J. Gen.
Physiol.  2, 305-313.

Lund, J.W.G. (1957).  Chemical  analysis in ecology
illustrated from Lake  District  tarns and lakes. 2.
Algal differences. Proc. Linn. Soc. Lond.I67,165-171.

Patrick,  R. (1957). Diatoms as indicators of changes
in environmental conditions. Trans. Seminar Biolog.
Prob.  Water  Pol., R. A. Taft  San. Eng. Center,
Cincinnati, Ohio, held 1956, p. 71-83.

Round, F.  E. (1953). An investigation of two benthic
algal communities in Malham  Tarn, Yorkshire. J.
Ecol., 41, 174-197.

Tailing,  J.  F. (1960).  Comparative laboratory  and
field studies of photosynthesis by a marine planktonic
diatom. Limnol. & Oceanogr. 5, 62-77.

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 34
ENVIRONMENTAL REQUIREMENTS OF PLANKTON ALGAE
                      THE IMPORTANCE OF EXTRACELLULAR PRODUCTS OF ALGAE

                                    IN THE AQUATIC ENVIRONMENT

                                               G. E.  Fogg*
   In the words of J. C. Smuts (1931)  "There is an
overflow  of organic wholes  beyond their apparent
spatial  limits."  In making this remark  Smuts had
in mind, not, perhaps, an overflow so excessive as to
be  described as pollution but the whole complex of
interactions between an organism and its environment;
it is with one aspect of this subtler kind of overflow
as  it occurs in algae that this paper  is concerned.
The mechanical  separation of the cells  of an alga
from the water in which they are growing is so easily
accomplished in the laboratory that we overlook the
fact that we thereby  disrupt  an organic system and
that the filtrate or supernatant that goes down the
drain may be something more than a solution of unused
nutrients.  Among other things, it may  contain meta-
bolites  that have been liberated from the cells and
which play a vital part in determining the activities of
the alga itself or of associated organisms.

   Oxygen is, of course, an extracellular product of
prime  importance, both generally and with respect to
pollution, but the possible significance in the aquatic
environment of organic substances excreted from algal
cells is less obvious.   There is, however, abundant
evidence that a variety of different organic substances
is liberated into the medium from healthy algal cells
in laboratory culture.   This includes carbohydrates,
fatty  acids, amino acids, polypeptides, growth sub-
stances, vitamins, antibiotics, and enzymes; the total
amount of extracellular material in a culture may
sometimes  be as much as that of  the cell material
itself.    Conditions in  laboratory  cultures  may, of
course,  be vastly  different  from  those  in  natural
environments but so far there is little evidence to
suggest that similar  excretion does not occur under
natural conditions, and the presence in natural waters
of appreciable concentrations of many of the substances
concerned has been  established (Fogg, 1962).  The
possibilities of extracellular products of algae having
effects  of biological importance in  aquatic environ-
ments  are  multifarious.  In this paper attention is
confined to three examples,  investigation of which
the author has personally conducted.

   Firstly, the possibility of  extracellular products
producing biological effects through chelation of ions
is considered. Excretion by algae of substances that
appear to be of the nature of polypeptides is evidently
common,  although  particularly evident in the blue-
green algae  (Fogg, 1962);  such substances would be
expected to possess chelating properties. By various
methods,  including electrometric titration, Fogg and
Westlake (1955)  were able to show that a partially
purified preparation of the extracellular polypeptides
                                of Anabaena cylindrica forms complexes with various
                                ions  including those of copper, zinc, ferric iron and
                                certain  organic  substances.   The value of  added
                                chelating agents in algal culture media is well known.
                                Besides maintaining trace elements in available form
                                they  may render a medium more favorable for growth
                                by altering the ratios of  major ions; e.g., chelating
                                agents improve the growth of Monodus  subterraneus
                                (an  obligatory phototrophic coccoid member  of the
                                Xanthophyceae) under certain conditions by reducing
                                the  effective  calcium/magnesium  ratio (Miller  and
                                Fogg, 1958).  Extracellular polypeptides may  act in
                                similar ways.  The potential biological importance of
                                this  for Anabaena cylindrica has been demonstrated
                                by showing  that complex formation between its  ex-
                                tracellular  products   and cupric  ion considerably
                                reduces  the  toxicity  of the  latter towards the alga
                                (Fogg and Westlake,  1955).  Peptide nitrogen occurs
                                dissolved in unpolluted fresh waters (Hutchinson, 1957)
                                in concentrations that are large relative to those of
                                many biologically  important  inorganic ions.   This
                                peptide nitrogen may originate only partly from living
                                algae but,  whatever  its  origin, it probably  exerts
                                appreciable  effects on the growth  of organisms in
                                the water by forming complexes with other dissolved
                                substances.   Possible effects might be to reduce the
                                efficiency of  copper  sulphate as an  algicide, or to
                                permit  algal  growth  in  waters polluted  with high
                                concentrations of heavy metal ions.  Thus high peptide
                                concentrations such as have been reported for Lake
                                Mendota  by Domogalla et al. (1925) would probably
                                be sufficient to render non-toxic  0.05 milligram of
                                copper per liter of water, a concentration which under
                                other circumstances  would be lethal  to most  algae.

                                  The second example, the production of extracellular
                                enzymes by  algae has  scarcely  been considered,
                                although  the ability of some species  to utilize sub-
                                strates  of  high molecular weight, such as  starch
                                and  proteins,  suggests that these are  sometimes
                                produced.   Monodus  subterraneus, which is able to
                                utilize a variety of organic substances as nitrogen
                                sources (Miller and Fogg, 1958), has been shown by
                                Miller (1959), however, to liberate an extracellular
                                glutaminase.  Cell-free filtrates from young  cultures
                                of the alga grown with either glutamine or nitrate  as the
                                nitrogen source catalyse the hydrolysis of glutamine to
                                glutamic acid and ammonia, and this property  is de-
                                stroyed by boiling.  The  enzyme is specific, neither
                                iso-glutamine nor asparagine being hydrolyzed by it.
                                Chlorella vulgaris  and several species of  Xantho-
                                phyceae  have been found not to produce a similar
                                enzyme (Miller, unpublished). It is impossible  to say
                                at present how widespread such liberation of  extra-
 * Department of Botany, Westfield College, London, England.

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                 The Importance of Extracellular Products of Algae in the Aquatic Environment
                                                 35
cellular  enzymes may  be, but it is possible that they
may be concerned to an appreciable extent in the break-
down of  organic matter in fresh water and thus help
to bring  about the  abatement   of pollution.  As
far as I am aware, no  investigations have been made
of the enzymic  activity of  fresh waters filtered to
remove all bacteria and other organisms; there are
indications, however, that sea-waters may contain dis-
solved enzymes (Harvey, 1955).

   Thirdly, I should like to  consider the excretion of
glycollic acid by plankton algae, a phenomenon which
various  pieces  of  evidence  indicate  as  being of
particular  importance  in the aquatic environment.

   It  is  now well  established  that  algae such as
Chlorella  liberate an  appreciable proportion of the
carbon, which they  fix in  short  periods of photo-
synthesis  in laboratory experiments in the  form of
glycollic acid (Tolbert and  Zill, 1957; Warburg  and
Krippahl, 1960; Pritchard, Griffin andWhittingham,in
press).      In addition  glycollic  acid has been
demonstrated in filtrates from laboratory  cultures of
Chlamydomonas  spp.   (Allen,  1956; Lewin, 1957) and
a  planktonic strain of  Chlorella pyrenoidosa  (Nale-
wajko, Chowdhuri and  Fogg, in press).  Pritchard et
al. (in press) found that glycollic acid is the principal
extracellular  product of Chlorella,  except  at very
alkaline pH values and high concentrations of carbon
dioxide; their results suggest that it accumulates when
the rate  of photosynthesis is carbon dioxide  limited.
Glycollate  can be reabsorbed by Chlorella  and results
of various  studies indicate that there is an equilibrium
between  its  intracellular  and  extracellular  concen-
trations.   A particularly  interesting finding is that
concentrations of glycollic  acid  of  the  order  of  1
milligram  per liter are effective in abolishing the lag
phase in the growth of  Chlorella pyrenoidosa under
light-limited  conditions.  Other organic  substances
such as glucose, and acetic,  pyruvic, and malic acids
do not do  this although they may  increase the total
amount of  growth in the culture. This suggests that
following   inoculation of this Chlorella  into  fresh
medium, glycollate  is  the  major product of photo-
synthesis and only when an equilibrium concentration
of this substance  has  been built up in the  medium
does  a  sufficient proportion  of the  output of  the
photo synthetic fixation  become available to maintain
exponential growth (Nalewajko et al., in press).

   The  available evidence  suggests  that  similar
excretion by phytoplankton occurs under natural con-
ditions.  We (Fogg  and Nalewajko, unpublished) have
now carried out a great many measurements of photo-
synthesis over periods of 3 to 24 hours, in situ in lakes,
by the radiocarbon method of Steemann Nielsen (1952),
in which, in addition to fixation of radiocarbon in par-
ticulate matter,  fixation of radiocarbon in dissolved
organic matter  has  also  been determined.  These
measurements have shown that fixation in extracel-
lular  organic matter always occurs, and amounts to
5 to  90 percent  of the  total fixation.  This extracel-
lular  fixation is  proportional to the amount of photo-
synthesis that has taken place, negligible  amounts of
Cl4  being fixed in  the filtrates from samples  kept
in dark bottles.   The principal extracellular product
produced by phytoplankton in short-term experiments
seems to be glycollate, just as in the case of Chlorella.
The radiocarbon fixed in  organic substances can be
recovered  completely from the filtrates from natural
phytoplankton samples by  distillation in vacua after
acidification.   Extracellular fixation is thus largely
in volatile  substances and glycollic acid canbe detected
in the distillates.  If the extracellular substances in
which radiocarbon is fixed were derived from broken
cells  they would be largely non-volatile.   These
results  support the  idea  that  glycollic  acid is
qualitatively the most important extracellular product
of phytoplankton under  the  conditions  of  these  ex-
periments, but unequivocal proof of this has yet to be
obtained.  Attempts to  demonstrate labelling in
extracellular glycollate by C14 supplied as bicarbonate
with radio-autography of chromatograms have so far
been unsuccessful.

   Glycollic acid is, however, normally present in lake
waters.  We have demonstrated its presence, qualita-
tively, in water from Windermere by paper chromato-
graphy.  Direct colorimetric  determination of water
samples is  unreliable;  it has been found  best to
extract the acid into ether  by a method similar to
that used by Koyama and  Thompson (1959) for sea-
water,  after  which  it  may  be determined by  the
colorimetric method  of Calkins (1943) with 2:7  di-
hydroxynaphthalene.   Some results obtained by this
method are as follows:—
                                     Glycollic acid

Windermere, North Basin April 1961  0.29  mg./liter
Windermere, North
   Basin              October 1961  0.045 "
Ennerdale Water         April 1961  0.12  "     "
Bassenthwaite            April 1961  0.13  "
Blelham Tarn             July 1961  0.12  "


   Kamata (unpublished) who estimated the amounts
of various organic acids in the waters of Lake Kizaki-
ko, Japan, by titration after  separation by chroma-
tography on silica gel, also found glycollic acid but
in smaller concentrations than those presented above.

   As far as it goes, this evidence strongly suggests
that  plankton algae under natural conditions normally
liberate  glycollic  acid from their cells during photo-
synthesis.   The extent of this loss cannot be judged
from the results  of the radiocarbon  determinations
reported  above, since,  if  glycollic  acid  is present
in the lake water, there may be absorption simul-
taneous  with the  escape of labelled molecules from
the  cells.   Thus, with very  low concentrations of
glycollic acid  in  the surrounding water,  the  radio-
activity of organic substances in the filtrate would be
expected to be a good measure of the loss of material
from the cells, whereas with higher concentrations
it might only  denote  an  exchange with no net loss
from the cells. The former state of affairs might be
expected to obtain at the end of the winter and, if the
supposition is correct that growth cannot begin until a
certain limiting concentration of glycollic acid  has
been established in the medium, this may  explain the
suddenness with which the spring outburst  of plankton
growth begins.  Only when conditions are favorable

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36
ENVIRONMENTAL REQUIREMENTS OF PLANKTON ALGAE
for photosynthesis  and when turbulence has dimin-
ished sufficiently for concentration gradients to be set
up  around the cells can  equilibrium be established
and the products of photosynthesis become available
for the building of cell material. It might be possible
to prevent plankton growth altogether  if some  suf-
ficiently effective means  of removing glycollic  acid
from the  water  could be found. It would be expected
that the position of equilibrium would vary according
to conditions so  that there  may be net absorption of
glycollic acid at times.  Thus, the finding of Pritchard
et al. (in press) that glycollate accumulation in the
medium  takes  place when photosynthesis  is carbon
dioxide  limited  suggests that  reabsorption of  this
substance occurs when photosynthesis is light limited
and thus that  growth  may be maintained under these
conditions at the expense of dissolved glycollic acid.
There is, in fact, some evidence that plankton algae
can assimilate dissolved organic substances (Fogg and
Belcher, 1961; Rodhe, in press)   and  grow in dark-
ness  (Rodhe, 1955).  Other organisms  besides algae
will,  of  course, utilize dissolved  glycollic acid.
Bacteria, such as Pseudomonas ovalis  and a mutant
Psuedomonas  B2 aba, which will grow on glycollate
as  sole  carbon  source,  have  been  investigated  by
Kornberg and  Gotto  (1961).   Lewin  (unpublished)
has isolated six strains of fresh-water bacteria able
to grow  on glycollate  as  sole carbon source.  We
have  found one  of these,  provisionally  called Gly-1,
to be capable of appreciable  growth  in  a medium
containing 10 milligrams glycollic acid  per liter,
and  presumably slow  growth  might be possible at
concentrations  as low  as those found naturally in
lakes. Using Cl4_iabelled glycollate we have demon-
                                strated appreciable uptake  by Daphnia from concen-
                                trations of the same order as those found in natural
                                waters, but it is clear that these  larger organisms
                                can only  obtain  a  minute fraction of their  total
                                carbon requirements from this  source.   Parsons
                                and Strickland (1962) have suggested that the amount
                                of  heterotrophic  carbon assimilation by  micro-
                                organisms in the sea may be a significant fraction
                                of the photosynthetic production, when considering the
                                whole  water-column in a  deep  ocean.   Similarly,
                                considering a fresh-water habitat  as a whole it may
                                be  that  a considerable proportion of  the  primary
                                production of cell  material is heterotrophic, taking
                                place  at  the  expense  of glycollate excreted by the
                                phytoplankton during photosynthesis.

                                   Our knowledge  of  the  extracellular products of
                                algae is still scanty; in particular, we are ignorant
                                of  what may be  the most important group from the
                                point of view  of pollution control - the antibiotics.
                                Pathogenic and coliform bacteria die out rather quickly
                                in  sewage oxidation ponds in which there is abundant
                                algal growth; this  could perhaps be the consequence
                                of  the production of antibacterial substances. There
                                is  evidence  that  some algal  species produce such
                                agents  in  culture  (see Fogg  1962) but it  is not yet
                                known how widespread such production is, nor is there
                                much  information  about the  chemical nature of the
                                substances.  A great deal  more investigation is re-
                                quired.  It is hoped that the discussion in this paper
                                will have  shown that  the  extracellular substances
                                of algae may be of considerable ecological importance
                                in  aquatic habitats and that  account must be  taken
                                of  them  when   considering problems  of  pollution.
                                              REFERENCES
Allen, Mary B.,  1956.   Excretion  of organic com-
pounds  by  Chlamydomonas.  Arch. Mikrobiol.,  24,
163-8.

Calkins, V.P., 1943.  Microdetermination of glycollic
and  oxalic acids.  Ind.  Eng.  Chemv Anal.  Ed.  15,
762-3.

Domogalla, B.P., Juday, C., & Peterson W.H. 1925.
The  forms of nitrogen found in certain lake waters.
Journ. Biological Chem., 63, 269-285.

Fogg, G.E. 1962.  Extracellular Products. Physiology
and  Biochemistry of the  Algae. Edited by R.A. Lewin.
Academic Press, New York. Chapter 30.

Fogg, G.  E., and Belcher, J. H. 1961.  Physiological
studies on a planktonic  " /* - alga".   Verh. Internal.
Verein. Limnol. 14, 893-896.

Fogg, G.E. & Westlake, D.F. 1955. The importance
of extracellular  products  of  algae  in freshwater.
Verh. Internal. Verein. Limnol. 12, 219-32.

Harvey, H.W.,  1955.   The Chemistry and Fertility
of Sea-waters.  Cambridge University Press.

Hutchinson, G.E.  1957.   A Treatise on Limnology.
Vol. 1. Wiley, New York
                                Kornberg, H. L., & Gotto, A. M. 1961. The metabolism
                                of  C2  compounds  in microorganisms 6.  Synthesis
                                of  cell constituents from glycollate by Pseudomonas
                                sp. Biochem, J., 78, 69-82.

                                Koyama,  T., & Thompson,  T.G. 1959.  Organic acids
                                in  sea water.  Communs.  Intern. Oceanog. Congr.,
                                New York.

                                Lewin, R.A. 1957.    Excretion of glycollic acid by
                                Chlamydomonas Bull. Japan, Soc. Phycol.  5,  74-75.
                                (In Japanese)

                                Miller, J.O.A  1959.   An extracellular enzyme pro-
                                duced by  Monodus.   Brit, Phycol. BuU. No. 7, 22.

                                Miller, J.D.A.,  &  Fogg, G.E. 1958.  Studies  on the
                                growth of Xanthophyceae in pure culture.  II.  The
                                relations  of Monodus  subterraneous  to organic sub-
                                stances. Arch. Mikrobiol., 30,  1-16.

                                Nalewajko, C., Chowdhuri, N. & Fogg,  G.E.  (in  press)
                                Growth and excretion of glycollic acid by a planktonic
                                Chlorella. Plant and Cell Physiology.

                                Nielsen, E. Steemann 1952. The use of radio-active
                                carbon (C-^) for measuring organic production in the
                                sea.   Journal de Conseil 18, 117-140.

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                                  Toxic Waterblooms of Blue-Green Algae
                                                37
Parsons,  T.R.,  &  Strickland, J.D.H. 1962.   On the
production of particulate  organic carbon by hetro-
trophic processes in sea water: Deep Sea Research
8, 211-222.


Pritchard, G.G., Griffin,  Wendy  J.,  & Wittingham,
C.P.  (in press).  The effect  of carbon dioxide con-
centration, light intensity  and zsonicotinyl hydrazide
on  the photo synthetic production  of  glycollic acid
by Chlorella. J.  Exp. Bot.


Rodhe,  W. 1955.   Can plankton production  proceed
during winter darkness in subarctic lakes?  Verh.
Internat. Verein. Limnol. 12, 117-122.
Rodhe,  W. 1962.  In Proceedings of the First Con-
ference on  Marine  Biology.  American Institute of
Biological Sciences.

Smuts, J.C.  1931.  Presidential Address to the Britsh
Association  for the Advancement of Science.

Tolbert, N.E. & Zill, L.P. 1957.  Excretion of glycollic
acid by Chlorella during photosynthesis.  Research in
photosynthesis,  edited  by H. Gaffron,  Interscience
Publishers,  Inc., New York, 228-231.

Warburg,  O., &  Krippahl, G.  1960.   Glykolsaure-
bildung in  Chlorella.  Z. Naturforschung., 15b, 197-
199.
                             TOXIC WATERBLOOMS OF BLUE-GREEN ALGAE

                                            PaulR. Gorham*
                 INTRODUCTION
   My part in this symposium  is to consider the
origin and development of toxic waterblooms of blue-
green  algae  and their effects upon water quality.
I shall talk, therefore, about the special case of those
waterblooms that cause death of livestock, pets, water-
fowl,  and other animals.   By "waterblooms" I mean
the heavy concentrations  of floating algae  that ac-
cumulate (usually in warm weather) in lakes, reser-
voirs, or ponds that have been naturally or artificially
fertilized with growth-promoting minerals and organic
substances. I use the term "concentrated waterbloom"
to describe the  thick, paint-like mess that results
when  winds blow these algae into shallow, inshore
waters.

   Most  of the well-known  cases of poisioning by
blue-green algae have involved livestock and pets, but
cases of algal  poisoning  of wild animals and birds
have  been described.  In this paper I shall discuss
in some detail what is known about livestock poisoning,
and review briefly what is known about the toxicity
of blue-green algae towards other animals and  man.

   Poisonings   by  blue-green algae  have  been re-
ported from  such  varied parts  of the world as
Australia, Argentina, Bermuda, Brazil, Canada, Israel,
U.S.A., Union of South Africa, and U.S.S.R.C5, 12, 16,
22, 33, 45, 50, 56).  Fitch et al.(20)ha.ve described five
outbreaks  of  algae  poisoning  investigated by the
Division  of Veterinary  Medicine at the University
of Minnesota  between  1918 and  1934.  In one case
the death of  1  sheep,  17 hogs, and about 50 chickens
occurred a short time after these animals had drunk
lake water containing  Coelosphaerium Kiitzingianum
and  Anabaena  flos-aquae.   In  another  case, nine
cattle died in about one hour and a half after drink-
ing from a lake containing a concentrated waterbloom
of blue-green algae.  In the same pasture there were
horses, sheep, hogs and other cattle that did not seem
to be affected, however.  Olson(33)has reported that
a concentrated waterbloom in  Fox Lake, Minnesota,
killed a  large number of hogs, ducks, chickens, and
other animals after they had consumed small quantities
of it.   When the  wind  changed direction the algae
accumulated  on the opposite shore and there killed
79 hogs,  2 horses, and an uncounted number of ducks,
cats, dogs, wild animals  and  birds.  A 0.1 milliliter
sample,   consisting predominantly  of Anabaena
Lemmermannii  (An. flos-aquae)  killed mice  within
20 minutes,  but 2.0 milliliter from a sample col-
lected from the same spot 9 days later killed animals
only after 5  hours.  In 1949,  Stewart, Barnum, and
Henderson (49)  investigated an outbreak  of algal
poisioning in Sturgeon Lake, Ontario.  Six gallons of
concentrated waterbloom, consisting predominantly of
species oiMicrocystis, Anabaena, No stoc,an\ALyngby a
was  administered  by stomach  tube to  an  1100-lb
cow  and  caused her  to  die  within  25 min.  A 0.1
milliliter dose given intraperitoneally was sufficient
to kill mice.  A 2.0 milliliter dose  was required to
kill  mice with  another sample from the same source
collected 10  days later.  The latter sample consisted
chiefly of Anabaena with  some Micro cystis. A third
collection, made 2 months later when algal growth
again appeared heavy, was non-toxic even when con-
centrated 10 times.
* Division of Applied Biology, National Research Council, Ottawa, Ontario, Canada.

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38
ENVIRONMENTAL REQUIREMENTS OF PLANKTON ALGAE
   These cases,  and  others that might  be cited,
illustrate the kind of evidence for the conclusion that
waterblooms are  in some way and under some con-
ditions  responsible for the sudden deaths of livestock
and other animals.   These cases also illustrate how
variable the apparent toxicity of waterblooms can be.
Species  composition undoubtedly  contributes to this
variation, but changes in toxicity have been observed
even  when  there  has  been no apparent change  in
the species composition of the bloom (34). Waterblooms
consisting predominantly of the following  six species*
have  been implicated in algal poisonings  (10, 16, 22,
37):MicrocystisaeruginosaKiitz.em. Elenkin(including
M. flos-aquae and  M.  toxica), Anabaenaflos-aquae
(Lyngb.)  de Breb.  (including Aw.   Lemmermannii),
Aphanizomenon flos-aquae (L.)  Ralfs, Gloeotrichia
echinulata  (J.E. Smith) P. Richter, Coelosphaerium
Kutzingianum Nag.,  and Nodularia spumigena Mert.
What causes waterblooms dominated by  one of these
species  to  be toxic at one time  and not another is
a problem that has long puzzled investigators. Various
workers  have  shown  that bacterial infections  or
recognized  toxins, including botulinus toxin, are not
involved  (10, 33,  58). Louw (25)  has suggested that
Microcystis toxin  is an alkaloid.


               LABORATORY STUDY

   About 8  years  ago a  laboratory study  of  this
problem  was  initiated in the Division of  Applied
Biology  of the National Research  Council  of Canada
at  Ottawa.   Our long-range objectives   were  to
answer the following questions:

   1. How many toxins  are involved?
   2. Do the algae produce  all of the toxins  or do
      the associated  bacteria also produce  some?
   3. What  is the chemical  nature  of  each toxin?

   The plan of study  we  adopted was  as follows:
   1. Locate  waterblooms  of the  suspected  species
      and test them for toxicity.
   2, Isolate and  culture strains  of suspect  species
      from toxic and non-toxic waterblooms.
   3. Grow  each  strain  in  sufficient  quantity  to
      test its toxicity on mice.
   4. Establish the  algal  or  bacterial  origin of
      each toxin.
   5. Mass  culture representative strains and  con-
      firm their toxicity on large animals.
   6. Isolate  and  determine  the  chemical structure
      of each toxin.

   We concentrated most of our attention  on water-
blooms  of  Microcystis aeruginosa  so a great deal
of what I have to say  about water bloom toxicity is
based on  conclusions  drawn from these studies (3,
 12, 14, 21,  28, 29, 46, 59).  We recently carried out
some studies on toxic waterblooms of Aphanizomenon
flos-aquae and Anabaena flos-aquae and I shall deal
with  these, as far as they have gone, after discussing
toxic Microcystis.
                                                  MICROCYSTIS


                                   The  very  first unialgal isolate  of  Microcystis
                                aeruginosa we managed to grow proved  to be  toxic
                                to mice when administered intraperitoneally or orally.
                                It  produces an  endotoxin,  which we call the  fast-
                                death factor (FDF)^; because a minimal lethal dose
                                kills  mice in  30 to 60 min» It produces symptoms of
                                pallor followed by violent convulsions and prostration.
                                Upon autopsy, the  liver has  a mottled  appearance
                                caused by cellular breakdown. The bacteria associated
                                with the  alga  also produce a toxin (or toxins), which
                                we called the slow-death factor (SDF). This produces
                                symptoms of piloerection, dyspnea, and lethargy and a
                                minimal  lethal dose causes death within 4 to 48 hr.
                                The  presence  of  SDF is frequently obscured by  the
                                presence of FDF.  Attempts to obtain a bacteria-free
                                culture   of toxic M. aeruginosa  NRC-1  have been
                                unsuccessful so far, but the results of toxicity tests
                                on  algal and  bacterial  fractions and other evidence
                                are  consistent with the conclusion that the origin of
                                FDF is the alga and the origin of SDF is the bacteria
                                (12,46). That FDF is an endotoxin is shown by the fact
                                that fresh  suspensions  of  cells are non-toxic.  They
                                become toxic,  however, if they are frozen and thawed,
                                sonic-disintegrated, or decomposed by semi-anaerobic
                                incubation  (21, 58). In nature, FDF must be released
                                by decomposition.  We mass-cultured M. aeruginosa
                                NRC-1 (31, 12) in a medium called No. 11, developed
                                for maximum  yield (21, 50). We produced a continuous
                                "laboratory bloom" on a scale sufficient to yield 1 to 2
                                kilograms of freeze-dried cells per month.
                                   In collaboration with the Animal Diseases Research
                                Institute,  Canada  Department of Agriculture, Hull,
                                Quebec,  toxicity tests on  large animals have been
                                carried out.   Freeze-dried  Microcystis cells con-
                                taining FDF killed a variety of animals when admin-
                                istered both  orally and intraperitioneally (12, 14).
                                Domestic ducks  were  resistant, however, so it is
                                unlikely  that FDF  caused waterfowl sickness.  The
                                symptoms   and  autopsy findings  agreed  quite well
                                with those  described for toxic Microcystis water-
                                blooms (1,  27, 48,  50).  A  sample was sent to Prof.
                                Douw G. Steyn in Pretoria, South Africa.  He kindly
                                tested  it on laboratory animals and reported that the
                                effects  were indistinguishable from  those  he had
                                observed  in  1943-45  during his  investigation  of
                                Microcystis poisonings  in  the Transvaal.   On this
                                evidence, we have  concluded that Microcystis FDF
                                is one of the important algal toxins.


                                   With large  quantities of toxic Microcystis cells
                                available, it was possible  to tackle the  problem of
                                isolating and identifying FDF.  This proved to be a
                                difficult task, since, at the outset, we had no diagnostic
                                chemical reactions. This meant that fractionationand
                                purification had to be guided by bioassay with mice.
                                Finally we  were able to show that FDF was not an
                                alkaloid, as Louw (25)  has suggested, but one of five
                                closely related polypeptides (3). Its molecular weight
 * Nomenclature according to Prescott, G.W. Algae of the Western Great Lakes Area.  Rev. Ed. Wm. C. Brown
   Publishers, Dubuque, Iowa, 1961.

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                                   Toxic Waterblooms of Blue-Green Algae
                                               39
is low, since it dialyzes slowly through Visking casing,
and it appears to be cyclic.  Upon hydrolysis it yields
seven amino acids in the following molar proportions:
                     aspartic
                     glutamic
                     D-serine
                     valine
                     orni thine
                     alanine
                     leucine
                                 10
   The  MLD  (IP)  for  mice  of  pure FDF  is 0.47
milligram per kilogram body weight, so it is only a
moderately toxic substance. FDF and the antibiotics
bacitricin  and gramicidin  S have a number of prop-
erties in  common.  All three are cyclic polypeptides
of low  molecular weight.  FDF, however, does not
inhibit the growth of such bacteria as Bacillus subtilis,
Staphy loco ecus aureus,  Escherichia coli, or  Pseu-
domonas hydrophila  (3),nor does it possess antigenic
activity (45).

   Our  work (12,  14, 46) and that of Thomson et al.
(51,  52) of the Defence  Research  Board  of  Canada
indicate   there is more than  one SDF produced by
the  different  bacteria  found in association with
Microcystis  and other blue-green algae.  Thompson
et al. found in a  survey of 25  algal collections that
Gram-negative rods were most common. Twenty-two
out  of  twenty-six isolates  of  such Gram-negative
bacteria produced  a heat-stable acid-stable, acetone-
precipitable  neurotoxin.  The chemical structure of
this  and  other slow-death factors is still unknown,
however.   The presence of large numbers of bacteria
in a waterbloom  is an additional complication that
must be considered in ascertaining the cause of any
toxicity.

   We tested a total of  10 Microcystis waterblooms
for toxicity and found that 7 contained FDF while the
remainder were either non-toxic or contained SDF.
Nineteen colonial isolates of M. aeruginosa have been
grown and tested.  Only eight produce FDF while the
rest are non-toxic or produce SDF.  We attempted,
without success, to  induce the production of FDF in
a non-toxic strain of M. aeruginosa by isolating and
transferring the bacteria from M. aeruginosa  NRC-1
(46). Hence, it appears that FDF production is controlled
genetically as well as physiologically.

                APHANIZOMENON

   There  are at least five case  histories on record
of poisonings  attributed  to waterblooms  consisting
mainly of  Aphanizomenon flos-aquae (22,  31, 32, 35),
36, 37).  Wheeler  et si.(58) tested almost pure Aph.
flos-aquae from  Minnesota on mice without effect.
In 1955,  we collected a bloom of almost pure Aph.
flos-aquae from the Rideau Canal,  Ottawa, Ontario,
freeze-dried  it, and tested its toxicity on mice.  It
produced  no  fast  deaths,  only slow deaths at high
dosage. In I960, through the cooperation of Professor
H.K. Phinney and  Mr. C.A. Peek of the Department
of Biology, University of Oregon, we obtained three
fresh samples of bloom,  consisting  of  Aph. flos-
aquae and M. aeruginosa in about equal proportions,
from  Klamath Lake, Oregon.   These samples  were
freeze-dried for testing.  We  also  obtained a  dried
sample of toxic bloom of similar composition collected
by Phinney and Peek from Klamath Lake in 1957  (35).
As  judged by the  symptoms and survival times  when
administered  intraperitoneally  to   mice,  all  four
samples contained only Microcystis FDF. One strain
of Aphanizomenon isolated  from the  Rideau Canal
bloom  and four strains isolated from a bloom col-
lected in 1960 from  Burton Lake, Saskatchewan (30)
are non-toxic, or produced only small amounts of SDF.
More work on the toxi city of Aphanizomenon is needed,
but from the evidence available so far it appears that
this  species  either   produces a toxin  that  is in-
distinguishable  from  Microcystis  FDF  or is  non-
toxic.
                    ANABAENA

   There  are at  least three case histories on record
of rapid deaths of livestock,  poultry, waterfowl, and
other animals  that are attributed to the consumption
of waterblooms composed mainly of Anabaena flos-
aquae  (An. Lemmermannii) (7, 9, 33, 42).   Survival
times  as short as 2 min have been reported.  This
fact,  together  with differences  in  water-fowl sus-
ceptibility (12) (Olson, private communication) suggests
that a toxin that is different from FDF is probably
involved.  We tested the toxicity of seven waterblooms
consisting mainly  of  An, flos-aquae.   Two freeze-
dried samples, collected from the same location from
Little  Rideau  Lake, Ontario, in June and October,
1955,  contained  only  SDF.  Five samples  collected
from Burton Lake, Saskatchewan in 1960 and 1961,
however,  killed  mice within  1  to 10  min after in-
traperitoneal  or oral administration  of a  minimal
lethal dose (13). These  very fast deaths were preceded
by paralysis, tremors, and mild convulsions. Upon
autopsy  the liver  appeared  normal.   Between  50
and  95 percent of this very-fast-death factor (VFDF)
was found in  the water.  Freeze-dried samples of
Burton  Lake bloom were sent to  Professor  L.D.
Jones,  D.V.M., South Dakota  State  College,   and
Professor T.A. Olson, University of Minnesota, for
comparative tests.   Both reported  that  symptoms
and survival times when tested on laboratory animals
were indistinguishable from  those observed with An.
flos-aquae during the  outbreak of algal poisonings at
Storm Lake, Iowa, in 1952(9, 42) and with toxic blooms
from Minnesota(33, 34),respectively.


   We succeeded in growing  14 strains of  An. flos-
aquae isolated  from two of the waterblooms collected
in Burton Lake in 1960 and 1961.  Cells or culture
filtrates  from  eight strains  contain  typical VFDF
while those from six strains do not.


   Anabaena VFDF acts  much more  rapidly  than
Microcystis  FDF.   This suggests that it is a smaller
molecule.   Anabaena  VFDF  is soluble in  water  or
ethanol,  insoluble  in  acetone, ether or chloroform
like  Microcystis  FDF (3), but VFDF  kills waterfowl
(33, 42) whereas FDF  does not.  Olson (33;isolated a
quantity of Anabaena VFDF from a waterbloom and

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40
ENVIRONMENTAL REQUIREMENTS OF PLANKTON ALGAE
separated it into several toxic fractions, one of which
has  a strong absorption between 210  and 290 milli-
microns.   The  chemical structure  of  VFDF and its
relation to FDF await further study.  This should be
possible now that we have toxic strains to produce it.

           OTHER SUSPECTED SPECIES

   We have not located any waterblooms dominated by
Gloeotrichia  echinulata, Coelosphaerium Kutzingia-
num, or  Nodularia  spumigena.  However, we  have
grown and tested the toxicity of one  strain each of
G. echinulata  and C. Kiitzingianum  (from the Cam-
bridge Culture  Collection) and Nodularia sphaerocarpa
Born, et  Flah.  (from the Indiana Culture Collection).
All  three are  non-toxic.   More blooms and strains
of these  suspect  species  need to be tested before
we can decide whether they, too, produce toxic strains.

           TOXICITY OF WATERBLOOMS

   The work described so far provides at least partial
answers  to the questions  concerning the toxicity of
waterblooms of blue-green algae towards livestockand
other mammals.  We  can  conclude that: (1) More
than one  toxin may be involved;  (2) the principal
toxins appear to be  algal  in orgin;  (3) bacteria may
also produce toxins; (4) one of the major algal toxins
is a polypeptide,  while another,  not  yet identified,
appears to be  different; (5) depending on the species
involved, algal  toxins are either excreted or released
into the surrounding water by decomposition; and (6)
the  variable toxicity of waterblooms  arises from  a
complex  of different factors.  These factors are too
numerous to discuss in detail, but they include dif-
ferences  in algal  and bacterial  strains,  species,
culture conditions, age, accumulation, secretion, and
decomposition,  and   also  differences  in toxin  de-
struction  or inactivation,  dosage, and animal  sus-
ceptibility.   It is  a  curious fact,  mentioned by
Singh(47),that many experiments in India with several
types of  blooms and different animals (guinea-pigs,
rabbits,  squirrels,  etc.)  have  given  no indications
of toxicity even though the  same species are involved
as those  in other  countries where  toxicity is en-
countered.  Whether this reflects strain differences,
physiological  differences,  or  both,  has not  been
determined.

                AQUATIC  ANIMALS

   A number of reports indicate that waterblooms of
blue-green algae are sometimes toxic to other animals
besides  mammals  and birds.   The toxic factors
involved  are not necessarily the same in every case,
of course.   Prescott (36) and Mackenthunetal.  (26)
have described experimental  fish  kills with  survival
times that varied  from 1  or  2 hours up to 34 hours,
which were caused by decomposition of concentrated
waterblooms of Aphanizomenan. At no  time did the
dissolved oxygen content drop sufficiently low to cause
death. Prescott analyzed the water and found that toxic
concentrations  of hydroxylamine were present. Hydro-
gen sulphide was also present at 8.5 ppm; he suggested
that it might be an  additional toxic agent.  Lefevre
et al. (24) described  a fish kill in  Morocco involving
a  waterbloom of Microcystis.  Here,  too, carp died
                               despite the presence of adequate amounts of dissolved
                               oxygen.  Shelubsky(45) showed that carp injected intra-
                               peritoneally  with toxic Microcystis cells (containing
                               FDF)  died  within  1 to 4  days.   Astakhova et al.(2)
                               concluded from experiments that both fresh and de-
                               composed samples of a waterbloom consisting of M.
                               aeruginosa, Aph. flos-aquae and An. flos-aquae were
                               highly toxic to carp  and that such waterblooms were
                               responsible for the widespread disease of carp that
                               has been observed in the  Volga delta since 1956.

                                   Shelubsky (45) reported that suspensions of Micro -
                               cystis  (containing  FDF) injected  intraperitoneally
                               and subcutaneously were  toxic  to frogs.   Prescott
                               (37) observed periodic deaths of large numbers of mud-
                               puppies  (Necturus) that he  correlated with blooms of
                               Aph. flos-aquae.    G\irevicti(17) reported that Oscil-
                               latoria stunts  the development of frog embryos and that
                               they eventually die.  Braginskiif^ tested the toxicity
                               of  decomposing   waterblooms  towards   Daphnia,
                               Cyclops,  and  other  zooplankton.   He  reports  that
                               Microcystis was exceptionally toxic and Aphanizomenon
                               was slightly  toxic, while blooms of two species of
                               Anabaena, Gloeotrichia natans, and the green alga,
                               Volvox,  were  harmless.   Dillenberg and Dehnel(8)
                               recently reported that 0.5 milliliter of a heavy bloom
                               consisting of  Anabaena  and  Aphanizomenon killed
                               mice within 8 hours and immobilized Daphnia within
                               30 minutes.
                                   Only  a few of the toxic effects on animals other
                               than mammals and birds have been adequately cor-
                               roborated  or  systematically  investigated.   Most
                               await  detailed study  to find  out whether the algae
                               are really  to blame,  either directly or indirectly,
                               for the toxicities.

                                                      MAN

                                   The  subject of algae  and medicine has  been
                               reviewed by Schwimmer and Schwimmer^S,). Heavy
                               concentration of blue-green algae in public water
                               supplies with their resulting organic load has been
                               cited as a possible factor in bringing about the epidemic
                               of human gastroenteritis that occurred in the drainage
                               basins of the  Ohio and Potomac  Rivers in  1930-31.
                               (53, 54, 55).   Dillenberg and DehnelfS; and Senior (44)
                               report three cases of  human nausea and gastroent-
                               eritis   following  ingestion   of  blue-green  algae in
                               Saskatchewan in 1959.  These were investigated by
                               the provincial health  service.   No Salmonella or
                               Entamoeba were found in the  stools but many cells
                               of  Microcystis and  Anabaena  were found, which
                               strongly suggested that the ingestion of waterblooms
                               had caused the ailments.  Cutaneous sensitization and
                               other allergic responses to blue-green algae have been
                               reported by  Cohen and Rief (6) and  Heise (19,20).

                                   DEVELOPMENT OF TOXIC WATERBLOOMS

                                   Let us turn, now, from  considering the  different
                               ways in which waterblooms of blue-green algae can
                               be toxic to  a consideration of what little  we know
                               about  environmental requirements for the  develop-
                               ment  of toxic waterblooms.   This problem really
                               has two aspects: (1) the factors influencing the pro-
                               duction of a toxic  situation at any one time; and (2)
                               the factors that determine whether an animal  will
                               consume a lethal dose at the same time.

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                                     Toxic Waterblooms of Blue-Green Algae
                                                  41
     Little is definitely known about what causes con-
  centrated waterblooms of blue-green algae to develop
  except that they occur in eutrophic waters during warm,
  sunny weather. Even less is known about what causes
  particular  (toxic)  strains  of particular  species  to
  become dominant.  We studied the growth  require-
  ments of one  toxic strain  of M. aeruginosa (NRC-1)
  and one toxic strain of An. flos -aquae  (NRC-44)  in
  considerable  detail  in the  laboratory  (13, 21, 59).
  Both  species  have fairly  critical  requirements for
  certain minerals.  The requirements for light, tem-
  perature,  pH, carbon dioxide,  and chelators appear
  to  be somewhat  less exacting.  When the  optimum
  laboratory  conditions are compared with  the  con-
  ditions observed  with blooms  of  these  species  in
  nature there is very little or no correspondence to be
  found.  This suggests that the conditions that deter mine
  the later stages of bloom development may exert their
  effects at earlier  stages, thereby complicating their
  detection and interpretation.

     The effects on waterbloom  development of  pre-
  dators (fish, zooplankton),  bacteria, and other algae,
  and such  extracellular  products  as organic acids,
  amino  acids,  amides, polysaccharides, polypeptides,
  enzymes,  vitamins,  growth  promoters and growth
  inhibitors (11,  15, 18, 23,  24, 37,  38, 39, 40, 41, 51,
  54) have either not been studied, or their study has
  barely begun.  It is quite evident, however, that a
  great many variables can  affect the development  of
  both  toxic and non-toxic waterblooms  of blue-green
  algae.

     For poisonings to occur,  at  least two other con-
  ditions must  be  met besides  the  development of a
  waterbloom dominated by toxic strains of algae and/or
  bacteria: (1) The bloom must accumulate in shallow
  water so  that the concentration  of toxins  that are
  liberated will not be reduced too rapidly by dilution,
  circulation,  or adsorption (3, 45, 58); (2) susceptible
   animals must be present at the right time and consume
   sufficient quantities  of  the toxins for the latter to be
   lethal despite  adsorptive detoxication in the stomach
   and gut.
                     CONCLUSIONS

      Toxic waterblooms of blue-green  algae are  de-
   trimental to water  quality because of the hazard
   they present not  only to livestock, wildlife and pets,
   but also to fish and other  animal life.  They are a
   potential hazard to public health, too, since they may
   cause gastritis and allergies.   They are a nuisance
   to recreation because of the unpleasant appearance and
   offensive odors associated with their decomposition.
   It is apparent that a great deal more study of all types
   of waterblooms is needed to deter mine more precisely
   the factors that are necessary for their development
   and  the  effects they have on water quality.  These
   studies  should  be  paralleled  and  supported  by
   physiological and biochemical studies in the laboratory
   of bloom-producing  algae and  associated bacteria.
   Such studies may never provide entirely satisfactory
   answers  to  every question we may ask about such
   complicated ecological  phenomena,  but they  should
   provide  a better understanding than we have at the
   present time.

                  ACKNOWLEDGMENTS

      This  study  has been carried out in collaboration,
   at various times, with  E.F.L.J. Anet,  C.T. Bishop,
   R.  E. Harris, E.O.  Hughes,  U.T.  Hammer,  W.K.
   Kim,  H. Konst,  M. McBride, P.D.  McKercher, J.
   McLachlan,  B. Simpson, and A. Zehnder.   The kind
   cooperation of Professors L.D. Jones, T.A. Olson,  and
   D.G. Steyn in making the comparative tests of toxicity
   and the valued assistance of  Jean Machin and D.E.
   Wright are gratefully acknowledged.
                                               REFERENCES
l.Ashworth,  C.T.  and M.F.  Mason.  Observations on
  the  pathological changes  produced by a toxic sub-
  stance present  in blue-green  algae  (Microcystis
  aeruginosa).   Amer.  J.  Path.  22: 369-383.  1946.

2.Astakhova, T.V., M.S.  Kun, and D.L. Teplyi.  Cause
  of carp disease in the lower VoJ.ga. Dokl. Akad. Nauk
  S.S.S.R.  133(5):  1205-1208. 1960.  (A.I.B.S. Transl.
  Doklady  (Biol.  Sci.  Sect.) 133 (1-6):  579-581. 1961
3.Bishop,  C.T., E.F.L.J. Anet and P.R.  Gorham. Iso-
  lation and  identification  of the  fast-death factor in
  Microcystis aeruginosa  NRC-1. Can.  J.  Biochem.
  Physiol. 37: 453-471. 1959.

4.Braginskil,  L.P.  O toksichnosti  sinezelenykh vo-
  doroslei.   (On  the toxicity  of  blue-green  water
  plants).  Priroda 1955(1): 117. 1955.
5.Branco, S.M. Algas toxicas-controle das toxinas em
  aguas de  abasticimento. Revista doDepartamanento
  de  Aguas e Esgotos de Sao Paulo (Brazil) 20(33):
  21-30; 20(34): 29-42. 1959.
 6. Cohen, S.G. and C.B. Rief.  Cutaneous sensitization
   to  blue-green algae.  J. Allergy. 24: 452-457.  1953.

 7.Deem, A.W. and F. Thorp.  Toxic algae in Colorado.
   J. Am. Vet. Med. Assoc. 95: 542-544. 1939.

 S.Dillenberg, H.O. and M.K. Dehnel.  Toxic waterbloom
   in  Saskatchewan,  1959.   Can. Med. Assoc.  J.  83:
   1151-1154. 1960.

 9.Firkins, G.S. Toxic algae poisoning. Iowa State Coll.
   Veterinarian 15: 151-152. 1953.

10. Fitch,  C.P., L.M. Bishop, W.L. Boyd, R.A.  Gortner,
   C.F. Rogers,  and J.E. Tilden.  "Waterbloom" as a
   cause  of  poisoning in domestic  animals.  Cornell
   Veterinarian 24(1): 30-39.  1934.

11.Fogg, G.E.  The  extracellular products of algae.  In
   Proceedings  of the Symposium  on  Algology, New
   Delhi,  India, December  1959. Ed. by  P. Kachrov.
   Ind.   Council of Agr. Res. New Delhi, p.  138-143.
   1960.

-------
   42
ENVIRONMENTAL REQUIREMENTS OF PLANKTON ALGAE
12.Gorham, P.R.    Toxic water-blooms of blue-green
   algae.  Can. Vet. J. 1(6):  235-245.  1960.

13. Gorham, P.R., J. McLachlan, U.T. Hammer and W.K.
   Kim.    Isolation  and  culture of  toxic  strains of
   Anabaena flos-aquae  (Lyngb.)  de  Breb.  Verb. int.
   Ver. Limnol. (in press)

14. Gorham, P.R., B. Simpson, C.T. Bishop, andE.F.L.J.
   Anet. Toxic waterblooms of blue-green algae. (Abstr.)
   Proc. IX Int. Bot. Congr. 2: 137. 1959,

IS.Goriunova, S.V. Chemical composition and secretions
   of living blue-green alga Oscillatoria splendida Grew.
   Izd. Akad, Nauk S.S.S.R. 157 p.  1950.

16. Grant,   G.A.  and E.O.  Hughes.    Development of
   toxicity in  blue-green  algae.  Can.  J. Public Health
   44: 334-339.  1953.


17.Gurevich,   F.A.   Sinezelenye  vodorosli  i  embriony
   presnovodnykh zhivotnykh,   (Blue-green algae and
   embryos of fresh-water animals)  Dokl.  Akad.  Nauk
   S.S.S.R. 68: 939-940.  1949.

18. Hartman,  R.T.   Algae and  metabolities of natural
   waters.  In  The  Ecology  of Algae.  A Symposium
   Held at the Pymatuning  Laboratory  of Field Biology
   on June 18 and 19, 1959. Ed. by C.A. Tyron, Jr., and
   R.T. Hartman.   Spec.  Publ.  No. 2, Pymatuning Lab.
   of Field Biol., Univ. of Pittsburgh,  p. 38-55.  1960.

19.Heise,  H.A. Symptoms of hay fever  caused by algae.
   J. Allergy 20: 383-385.  1949.


20.Heise,  H.A.  Symptoms of hay fever  caused by algae.
   H.  Microcystts,  Another form of  algae producing
   allergenic  reactions.   Ann.  Allergy  9:   100-101.
   1951.

21.Hughes, E.O., P.R. Gorham, and A. Zehnder. Toxicity
   o* a  unialgal  culture of  Microcystis  aeruginosa.
   Can. J. Microbiol. 4: 225-236.  1958.

2?.Ingram, W.M., and  G. W. Prescott.  Toxic fresh-
   water algae.  Amer. Midland Naturalist 52: 75-87.
   1954.

23.Jakob,   H.  Compatibilities  et antagonismes  entre
   algues  du  sol.  C.R. Acad. Sci. 238: 928-930.  1954.


24.Lefevre, M., H. Jakob and M. Nisbet, Auto-et hetero-
   antagonisme chez  les algues d'eau douce in vitro et
   dans les  collections  d'eau  naturelles.   Ann. Sta.
   Centr. Hydrobiol. Appl. 4: 5-198.  1952.

25.Louw, P.G.J. The active constituent of the poisonous
   algae,  Mycrocystts  toxica  Stephens.  The  So. Afr.
   Indust. Chemist 4: 62-66. 1950.
26.Mackenthun,  K.M., E.F. Herman, and A.F. Bartsch.
   A  heavy mortality of fishes  resulting from the de-
   composition of algae in the Yahara River, Wisconsin.
   Trans. Amer. Fisheries Soc. (for 1945) 75: 175-180,
   1948.
                            27.Mason,  M.F. and R.E. Wheeler.
                               the toxicity of  blue-green  algae.
                               Soc. Exp. Biol.  1: 124. 1942.
Observations upon
Fed. Proc. Amer.
                             28.McLachlan, J. and P.R. Gorham. Growth of Microcystis
                               aeruginosa Kiitz. in a precipitate-free medium buffered
                               with  Tris.  Can. J. Microbiol. 7: 869-882.   1961.

                             29.McLachlan, J.,  and P.R.  Gorham.  Effects of pH and
                               nitrogen sources on growth of Microcystis aeruginosa
                               Kutz.  Can. J. Microbiol. 8: 1-11.  1962.

                             30. McLachlan,  J., U.T.  Hammer,  and P.R.  Gorham.
                               Observations on the growth  and  colony habits of ten
                               strains  of  Aphanizomenon  flos-aquae  (L.)  Ralfs.
                               Phycologia. 2(4): 157-168.  1963.

                             Sl.McLeod, J.A., and G.F. Bondar.  A case of suspected
                               algal  poisoning in Manitoba.  Can. J. Publ. Health
                               43: 347-350. 1952.

                             32.Nelson, N.P.B.  Observations upon some algae which
                               cause "water bloom."  Minn.  Bot. Stud. 3, Bot. Ser. 6:
                               51-56.  1903-04.

                             33. Olson,  T.A.   Toxic plankton.  In Proceedings of
                               Inservice Training Course in Water Works Problems.
                               Feb.   15-16,  1951.    Univ.  Mich.  School  of Publ.
                               Health, Ann Arbor, p. 86-95.  1951.

                             34. Olson, T.A.  Water poisoning - A study of poisonous
                               algae blooms in Minnesota.   Amer. J. Publ. Health
                               50: 883-884. 1960.

                             SS.Phinney,  H.K.,  and C.A.  Peek.  Klamath  Lake, an
                               instance of natural enrichment. In Algae  and Metro-
                               politan Wastes.   Transactions of the  1960  Seminar.
                               U.S.  Dept.  Health,  Educ. and Welfare.     Robt.  A.
                               Taft  Sanitary Engineering Center, Cincinnati, Ohio,
                               p. 22-27.  1961.

                             36.Prescott, G. W. Objectionable algae with reference
                               to the killing of fish and other animals.  Hydrobiol.
                               1: 1-13.  1948.

                             37.Prescott,  G.W.   Biological  disturbances  resulting
                               from algal populations in standing waters.  In  The
                               Ecology  of Algae.  A  Symposium Held at the Pyma-
                               tuning Laboratory  of  Field  Biology on June 18 and
                               19, 1959.  Ed. by C.A. Tyron, Jr. and R.T. Hartman.
                               Spec.  Publ. No. 2, Pymatuning Laboratory of Field
                               Biol., Univ. of Pittsburgh,  p. 22-37.  1960.

                             38.Proctor,  V.W.    Some   controlling  factors in the
                               distribution of  Haematacoccus pluviatis.   Ecol. 38:
                               457-462.  1957.

                             39.Proctor,  V.W.    Studies  of algal  antibiosis using
                               Haematacoccus  and Chlamydomonas.   Limnol. and
                               Oceanog. 2: 125-139.  1957.

                             40.Provasoli, L.   Micronutrients and heterotrophy as
                               possible  factors  in  bloom  production  in natural
                               waters.  In  Algae and Metropolitan Wastes. Trans-
                               actions of the 1960 Seminar.  U.S. Dept. of Health,
                               Educ. and Welfare. Robt. A. Taft Sanitary Engineering
                               Center, Cincinnati, Ohio. p. 48-56.  1961.

-------
                                      Toxic Waterblooms of Blue-Green Algae
                                                  43
41.Provasoli,  L.,  and I.J. Pintner. Artificial media for
   fresh-water algae: problems and  suggestions.   In
   The  Ecology of  Algae.   A Symposium Held  at the
   Pymatuning Laboratory of Field Biology  on June 18
   and  19,  1959.   Spec.  Publ. No. 2. Pymatuning Lab.
   of Field  Biol.,  Univ.  of Pittsburgh, p. 84-96.  1960.

42. Rose,  E.T. Toxic algae in Iowa lakes.  Proc. Iowa
   Acad. Sci. 60: 738-745. 1953.

43.Schwimmer, M., and  D.  Schwimmer.  The role of
   algae and plankton in  medicine.  Grune and Stratton.
   New  York and London. 1955.

44. Senior, V.E. Algal poisoning in Saskatchewan.  Can.
   J. Comp. Med. 24(1): 26-31. 1960.

45.Shelubsky,  M,  Observation on  the  properties  of a
   toxin produced by Microcystis. Verh. int. Ver. Limnol.
   11: 362-366. 1951.

46. Simpson, B., and P.R, Gorham.  Source of the fast-
   death  factor produced by  unialgal  Microcystis
   aeruginosa NRC-1 (Abstr.) Phycol. Soc. Amer, News
   Bull. 11:  59-60.  1958.

47. Singh,  R.N. Limnological relations of  Indian inland
   waters with special reference to waterblooms. Verh.
   int. Ver.  Limnol. 12: 831-836. 1955.

48. Smit,  J.D. Experimental cases of algae poisoning in
   small animals.  So. African Industrial Chemist 4: 66.
   1950.

49. Stewart,  A.G.,  D.A.  Barnum,  and J,A. Henderson.
   Algal poisoning on  Ontario. Can. J, Comp. Med. 14:
   197-202.  1950.

50. Steyn,  D.G. Poisoning of animals by algae (scum or
   waterbloom) in dams  and pans. Union of So. Africa,
   Dept. of Agr. and Forestry.  Govt. Printer, Pretoria.
   1945.
51. Thomson, W.K. Toxic algae. V. Study of toxic bacterial
   contaminants. DRKL Rept. No.  63.  Defence  Res.
   Board of Canada. August 1958.

52. Thomson, W.K., A.C.  Laing, and  G.A. Grant. Toxic
   Algae. IV.  Isolation of toxic bacterial contaminants
   DRKL Rept.  No.  51, Defence Res. Board of  Canada,
   September 1957.


53. Tisdale,  E.S.   Epidemic  of intestinal disorders in
   Charleston, West Virginia, occurring simultaneously
   with unprecedented water  supply conditions.  Amer.
   J. Public Health 21: 198-200. 1931.

54. Tisdale,  E.S.   The 1930-31  drought and its effect
   upon  water  supply.   Amer.  J. Public  Health 21:
   1203-1215. 1931.


55. Veldee,  M.V.  Epidemiological study of  suspected
   water-borne  gastroenteritis. Amer. J. Public Health
   21: 1227-1235.  1931.

56.Vinberg,  G.G.  Toksicheskii fitoplankton.    Uspekhi
   Sovr.  Biologii   38,  2(5):  216-226.   1954.   (Toxic
   phytoplankton, N.R.C.  Tech. Transl. TT-549. 1955)

57.Watanabe, A. Production in cultural solution  of some
   amino acids  by atmospheric  nitrogen fixing blue-
   green  algae.   Arch. Biochem. Biophys. 34: 50-55,
   1951.


58. Wheeler, R.E., J.B. Lackey, and S.A. Schott.  Contri-
   bution on the toxicity of algae. Pub. Health  Reports
   57: 1695-1701.  1942.

59. Zehnder, A., and P.R. Gorham. Factor ^influencing
   the growth of Microcystis aeruginosa Kutz.  emend.
   Elenkin. Can. J. Microbiol, 6:645-660. 1960.
                                                 DISCUSSION
      Emphasis was made that in evaluating the effects
   of  pollution upon  the  biota  of  a stream, the mere
   identification of the diatom  species present is  not
   sufficient, but  quantitative data  must  be obtained.
   Also,  it  was pointed  out  that it is not adequate to
   give a range of pollutional tolerance between which a
   diatom is found.   For  example, a species of diatoms
   may be absent  where there is low dissolved oxygen.
   However, the low  dissolved oxygen  may,  in turn, be
   due to the presence of such  things as  sulfides or
   ammonia, and  these  compounds may, in  fact, be
   responsible for the absence of that particular diatom
   species and not the low dissolved oxygen.

      One discusser  expressed  the opinion that  there
   should be two expressions for describing an ecological
   situation; the  ecobalance and ecoexistence  and that
   ecoexistence  could  not  be  properly described by
   making physiological observations alone.
      A  great deal of the discussion centered  about
   the methods of diatom sampling in a river or a stream
   in order to obtain a representative flora.  Dr. Round
   suggested that,  insofar  as  determining the diatom
   population  as related  to the degree of pollution is
   concerned, an  examination  of the bottom sediment
   would perhaps  be  a better  method.  In his studies
   he had  found little or  no  comparison between the
   diatom flora of  the sediment and that found on glass
   slides  suspended  in  the  water.   Also,  since  he
   assumed that a  stream contained no true planktonic
   forms, the flora of the sediment was a more reliable
   index.

      Dr. Patrick  suggested that perhaps Dr. Round had
   not used the  glass  slides in the same manner as she
   does, and,  therefore, had obtained different results.
   She said that when a capable diatomist was in the
   field and  collected and identified all the diatom

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44
ENVIRONMENTAL REQUIREMENTS OF PLANKTON ALGAE
habitats  of  a particular  area where glass  slides
had  also  been suspended for two  weeks,  70 to 80
percent of the species found on the slides were found
in the specimens  collected by the diatomist when
8,000 specimens were examined.   Of the  20 to 30
percent of those  not found  by the diatomist, over 90
percent were represented  by only  six  specimens.
She  also pointed  out that her  pollutional studies are
aimed at  finding changes  in the structure of the
community of diatoms and in order to do this  samples
must be  compared from areas above and below the
pollution. Since diatoms are not randomly distributed,
this  is difficult to do without introducing an artificial
substrate.   Also, when a glass slide was suspended
vertically, a majority of the species present was
obtained.    However,  when suspended horizontally,
a great deal of mud adhered to the slide.  Dr. Round
pointed  out that  he  would expect  less of the bottom
forms to be present when a slide was vertically
suspended.

   Dr. Williams  pointed out that because water plant
operators are interested in knowing what organisms
are  in the water and the dispersed organisms rep-
resent the greatest volume of water, the National Water
Quality Network Program (USPHS), is more interested
in the diatoms that  are planktonic.  Also, because of
the  magnitude of the sampling program, they must
limit their microscopic observations to the dominant
forms, and it is  his feeling that this type of  analysis
gives results that are  indicative of the condition of
the stream when samples are taken at the proper time.

   Dr. Round agreed that from a waterworks point of
view, one needed to  know about the so-called plank-
tonic forms. However, in dealing with pollution these
are of little value because pollutants are not ordinarily
discharged into the middle of a body of water and, as
previously pointed out, there is really no true plankton
in a stream.

   Dr. Patrick  agreed with  Dr. Round's proposal
for the examination of sediments if one  is desirous
of finding out where the diatoms grow. In a pollution
study, however, the evaluation must be carried out as
quickly as possible.  The study should not be limited
to the dominant  species because there is a great
difference  between  the dominant species alone and
the dominant species plus others.

   Other workers confirmed Dr. Fogg's observations
regarding the amounts of radioactivity excreted by the
algae after  they were allowed to assimilate radio-
                                active  carbon.  It was noted also that  extracellular
                                excretion was dependent upon such things as photo-
                                synthetic rates and time.

                                   The production of extracellular algal enzymes was
                                also  noted.  Phosphatase,  saccharase (sucrase), and
                                amylase have been found in natural habitats, and there
                                was  a correlation  between their presence  and the
                                annual plankton  cycle.  It was also pointed  out that
                                in the natural  habitat  Scenedesmus takes  up  sub-
                                stances just before the time  of cell division, and,
                                correspondingly, cell division is dependent upon light.

                                   In work concerning the origin of nitrogen in lake
                                water, there is  evidence  that  a great  deal of the
                                nitrogen is derived from extracellular products, and
                                the concentration of nitrogen in  the water is related
                                to the detention  time.  Although the nitrogen could
                                result  from  decaying cells, the evidence indicates
                                that it is liberated also from living cells.

                                   The question  was raised as to whether the pH
                                rise  observed at the occurrence of a bloom  of blue-
                                green algae was  the result of  the bloom or  whether
                                the pH was  relatively high in the beginning. It was
                                suggested that  the pH was probably  high in the
                                beginning.  The  removal of carbon dioxide, however,
                                by photosynthetic activity and the release of amines
                                by the algae would certainly cause the pH to rise as
                                growth proceeds.

                                   Another worker described the appearance of a bloom
                                of Oscillatoria  rubescens, after which  a  fish  kill
                                occurred.  Although the death of the fish was thought
                                to be the  result of oxygen depletion, this observation
                                required a study of the possible toxicity of this species
                                o! algae.  Apparently there are no reports of Oscil-
                                latoria being toxic  to fish.  There are reports of it
                                having influenced the breeding of fishes in Scotland,
                                however.

                                   While  there was no information offered during the
                                discussion relating to the  toxicity  of  blue-green
                                algae to insects, it was stated that there was evidence
                                of Anabaena controlling the population of mosquito
                                larvae in the rice fields of California.

                                   Cases of human toxicity of blue-green algae were
                                discussed where children and adults, after swimming
                                in water  containing the algal bloom, developed high
                                fever and diarrhea.  Suspecting malaria, examination
                                of the stool revealed  the presence  of  blue-green
                                algae.

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                               ENVIRONMENTAL REQUIREMENTS

                              OF FRESH-WATER  INVERTEBRATES
                                      L. A. Chambers,* Chairman
           BACTERIA-PROTOZOA AS TOXICOLOGICAL INDICATORS IN PURIFYING WATER

                       S. H. Hutner, Herman Baker, S. Aaronson and A. C. Zahalskyt
   There is a cynical adage that all travellers become
entomologists.   But, now with DDT and  detergents,
travellers  and  stay-at-homes  alike  are becoming
toxicologists. We have an immediate interest in pollu-
tion problems:   Our laboratory  receives, like the
East River  and  adjoining United Nations buildings, a
generous sootfall from a nearby power plant. Also,
we have seen a superb fishing  ground, Jamaica Bay
in New York City, become a sewer.  (Jamaica Bay is,
however, being  restored to its pristine cleanliness—
but not  the U.N. area.) We take our theme neverthe-
less not from  aesthetics but  from  statements by
Berger  (1961):   (1)  It is an expensive, time-con-
suming  project  "... to  predict with confidence  a
new waste's probable impact on certain important
downstream water uses.' And (2)  "The toxicological
phase of the study is perhaps its most  perplexing as-
pect.  The specialized services and cost necessary
for determining the effect of repeated exposure to low
concentrations of the waste for long periods of time
would inevitably place this job  out of reach of most
public  agencies.  Equally discouraging, perhaps,  is
the probability that the toxicological study may take
as long as two years."

   As described here, advances in microbiology offer
hopes of lightening this burden.  The first question is:
What kind of microcosm  will serve for toxicological
surveys, especially  for  predicting  the poisoning  of
biological means of  waste disposal?  The second is:
Can the protozoa of this  microcosm predict toxicity
to higher animals?

   The  food-chain pyramids  of sewage  plants and
polluted water shave been adequately described (Hynes,
1960; Hawkes, 1960).  A problem treated here is how
to scale those microcosms to experimentally manip-
ulable  microcosms  yielding  dependable predictions
for the behavior  of sewage-plant microcosms.

   THE WINOGRADSKY COLUMN AS SOURCE OF
    INOCULA FOR MINERALIZATIONS AND AS
      TOXICOLOGICAL INDICATOR SYSTEM

   Total toxicity depends  on  intrinsic toxicity-per-
sistence relationship.  Techniques for testing the
degradability  of organic compounds—and  so their
persistence  in soil and water—are still  haphazard.
The enrichment culture technique, in which one seeks
microbes that use the compound in question as sole
substrate—hence degrades it and even "mineralizes"
it—was  developed  by the Dutch  school of micro-
biologists.  Enrichment  cultures are used  routinely
by  biochemists wishing to work out the microbial
catabolic metabolic pathway for a  compound of bio-
chemical interest.  Since the compounds dealt with by
biochemists  are of biological origin,  microbial  de-
gradability can be  assumed. Still,  finding a microbe
to  degrade  a rare biochemical is  not always easy:
Dubos, in a  classical hunt for a microbe able to live
off  the capsules of pneumococci, found the bacterium
only after a  long search which ended in a cranberry
bog. Such difficulty in finding microbes that degrade
rare biochemicals  implies an even greater  difficulty
in finding microbes that degrade many products of the
synthetic organic  chemicals  industry,  since such
compounds may embody biochemically rare or bio-
chemically nonexistent linkages.   Intimations of the
importance of inoculum abound in the literature, e.g.,
Ross  and Sheppard (1956) could not at first obtain
phenol oxidizers from ordinary inocula (presumably
soil and  water), but manure  and  a trickling filter
from  a  chemical plant  proved abundant sources of
active bacteria.  One wonders how extensive a study
underlies the statement quoted by  Alexander (1961)
that "soils  treated with 2,4,5-T (trichlorophenoxy-
acetic  acid)  still retain the pesticide long  after  all
vestiges  of toxicity due to equivalent quantities of
2,4-D have disappeared."

   What  then is a reasonable inoculum for testing a
compound's susceptibility to microbial attack? The
size range is wide:  from the traditional crumb or
gram of  soil or mud to the scow-load of  activated
sludge contributed by New York City to inaugurate the
Yonkers  sewage-disposal plant.  We suggest that to
strike a  practical mean in getting  a profile of soil,
mud,  or  sludge to be used as inoculum the uses of
the Winogradsky column should  be  explored.  Di-
rections  for Winogradsky column and  bacteriological
enrichments  have  been  detailed (Hutner, 1962)  and
so  only  an outline is  given  here.   The column is
prepared by putting a paste of shredded paper, CaCO3,
and CaSO4 at the bottom of a hydrometer jar, filling
the  jar   with  mud  smelling of ^S, covering with a
shallow  layer  of water, and  illuminating  from  the
side with an incandescent lamp. In 2 or 3 weeks  sharp
zones appear: a green-and-black anaerobic zone at
the  bottom (a mixture of green photosynthetic bacteria
along with SO4-reducers, methane producers, and the
  Director, Allan Hancock Foundation and Head, Biol. Dept., Univ. South. Calif.

  Haskins Laboratories, 305 E. 43rd St., New York 17, N. Y., and Seton Hall College of Medicine and Dentistry,
  Jersey City, N. J. Pharmacological work from Haskins Laboratories discussed here was assisted by grant
  R6-9103, Div. of General Medical Sciences of the National Institutes  of Health. Paper presented by S.H. Hutner.
                                                   45

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46
ENVIRONMENTAL REQUIREMENTS OF FRESH-WATER INVERTEBRATES
like); over  that  a red  zone (predominantly photo-
synthetic  bacteria);  above  this garnet  or magenta
spots or zone (predominantly non-sulfur photosynthe-
tic bacteria); above  this a layer rich in blue-green
algae (the transition to the aerobic zones); above this
aerobic bacteria along  with  green algae, diatoms,
other algae, and  an assortment of protozoa.  This
makes an excellent  simple  classroom experiment to
demonstrate the  different  kinds  of photosynthetic
organisms,  especially the bacterial forms that  are
important in photosynthesis research and that ordi-
narily  escape notice yet are  ubiquitous in wet soils
and natural waters.

   As pointed out by our colleague, Dr. L. Provasoli
(1961), the heterotrophic capacities of algae are very
imperfectly known.  This is  underscored by recent
studies  of  the green flagellate Chlamydomonas
mundana as a dominant in sewage lagoons in the
Imperial Valley of California (Eppley and MaciasR,
1962);  other than that it prefers acetate among the
few  substrates tried;  its  heterotrophic  capacities
are  unknown.  More unexpectedly, some strains of
the photosynthetic bacterium  Rhodopseudomonas pa-
lustris use benzoic acid anaerobically  as the  re-
ductant in photosynthesis (Scher, Scher,  and Hutner,
1962),  narrowing the gap between the photosynthetic
pseudomonads  and the  ubiquitous  pseudomonads so
often represented among bacteria  attacking resis-
tant  substrates (eg., hydrocarbons) as well as highly
vulnerable  substrates.   For the  widely  studied,
strongly  heterotrophic photosynthetic flagellates
Euglena gracilis  and E.  viridis,  common in sewage,
no specific  enrichment procedure is known, meaning
that  their  ecological  niches are unknown but laboratory
data provide hints.

   The increasing use of oxidation ponds would in any
case urge  a greater use of  scaled-down ecological
systems in  which development of none of the photo-
synthesizers present  in the  original inoculum was
suppressed.  Conceivably, some of the rare microbes
attacking  rare substrates—and such microbes  are
likely to represent a source  of degraders of resis-
tant  non-biochemicals—are  specialists in attacking
products of photosynthetic organisms.

   Traditionally,  the  inoculum for  a  Winogradsky
column is a marine or brackish mud (as New Yorkers
we would  be partial to mud from flats of the Harlem
River).   Little is known about the effectiveness as
inocula of freshwater muds  or water-logged  soils.
It would be valuable to  know how complete a column
could develop from  material  from a trickling filter
or an activated-sludge plant.  A practical issue is:
Might  the  poisoning of  a  sewage-oxidation system
be  paralleled  by the poisoning of  a  Winogradsky
column, where the poison was mixed with the inoculum
for the column?  Might  the variously colored photo -
synthetic  zones of the column and the aerobic popu-
lation  on  top provide  sensitive indicators for  the
performance of a sewage-oxidation system subjected
to chemical wastes?

   If a particular compound mixed with inoculation mud
or sludge suppressed  development of the full Wino-
gradsky pattern, one might assume that  the compound
                                       at the test concentration was poisonous and persis-
                                       tent.   Biological  destruction of such poisons, if at
                                       all possible, might demand a long hunt for suitable
                                       microorganisms, then buildup  of  the  culture to  a
                                       practical  scale.   This  might best be done with il-
                                       luminated shake or aerated cultures, with the inocula
                                       coming from a variety of environments.  Optimism
                                       that microbes can be  found capable  of breaking almost
                                       all the linkages of  organic  chemistry is fostered
                                       by the study of antibiotics, which include a  wealth
                                       of  previously "unphysiological* linkages--azo com-
                                       pounds, oximes,  N-oxides,  aliphatic and  aromatic
                                       nitro   and  halogen compounds, and strange heter-
                                       ocyclic ring systems.  Some natural  heterocycles,
                                       e.g.,  pulcherriminic  acid and  2-«-nonyl-4-hydrox-
                                       yquinoline,  have a disquieting resemblance to the
                                       potent carcinogen 4-nitroquinoline N-oxide.

                                             PROTOZOA AS TOXICOLOGICAL TOOLS

                                          A  difficult  problem  is  one mentioned earlier:
                                       persistence joined with  low-grade  toxicity to higher
                                       animals.  Recent developments in the use of protozoa
                                       as pharmacological  tools show  that  protozoa  can
                                       serve as sensitive  detectors  of  metabolic lesions
                                       ("side actions*?)   of a wide assortment  of  "safe"
                                       drugs.  The list includes the  "anticholesterol"  tri-
                                       paranol  (MER/29).   Triparanol toxicity manifested
                                       itself  with  several protozoa, including Ochromonas
                                       danica  (Aaronson  etal.,   1962)  and Tetrahymena
                                       (Holz et al., 1962). Triparanol was not acting simply
                                       as an  anti-cholesterol  for its  obvious toxicity to
                                       protozoa was annulled by fatty acids as well as by
                                       sterols.    The  connection  between the  protozoan
                                       results and the  "side actions" of triparanol — bald-
                                       ness, impotence, and cataracts — are  of course un-
                                       clear, but protozoal toxicity might  serve as an initial
                                       warning that it might not be as harmless as assumed
                                       from  short-term  experiments with higher animals.

                                           The anticonvulsant primidone  provides a clear
                                       indication  of  how protozoa can be used to pinpoint
                                       the location of  a metabolic lesion,  Primidone had
                                       been  known to cause folic acid-responsive anemias.
                                       It  is  therefore  easy to find that  with joint use of a
                                       thymine-dependent Escherichia coli and the flagellate
                                       Crithidia fasciculate,  reversal  of  growth  inhibition
                                       by folic acid and related  compounds permitted the
                                       charting of interferences with the inter connected folic
                                       acid,   biopterin,  and DNA  function (Baker et  al.,
                                       1962), which amply accounted for  the  megaloblastic
                                       anemias.   Lactobacillus casei, a bacterium much
                                       used  in chemotherapeutic research, was unaffected
                                       by the drug.

                                           In another instance, where the  mode of action of
                                       the  drug in higher  animals was unknown,  growth
                                       inhibition property of the anticancer  compound 1-
                                       aminocrycfopentane-l-carboxylic  acid  was  reversed
                                       for Ochromonas danica  by L-alanine  and glycine,
                                       as was the inhibition property of l-amino-3-methyl-
                                       cjc/ohexane-1-carboxylic  acid by  L-leucine (Aaron-
                                       son and Bensky, 1962).

                                           Growth  inhibition  of Euglena by the potent carcin-
                                       ogen  4-nitroquinoline  N-oxide  was  annulled by a
                                       combination of  tryptophan,  tyrosine,  nicotinic acid,

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                              Bacteria-Protozoa as Toxicological Indicators
                                               47
phenylalanine,  uracil (Zahalsky et  al.,  1962) and,
in more recent experiments, the vitamin K relative
phthiocol.   These N-oxides  are of interest because
of recent work indicating that perhaps the main way
in which the  body converts such compounds as the
amino hydrocarbons  to  the  actual carcinogens may
be by an initial hydroxylation of the nitrogen, e.g.,
work by Miller et al., (1961). Whether the peroxides
in photo-chemical  smogs  of the Los Angeles type
act  on  hydrocarbons to produce carcinogenic N-
oxides  is  entirely unknown.   Leighton  (1961) lists
an array of peroxy  reactions produced  by sunlight
in polluted air.

   Our  aforementioned experience with primidone, a
ketonic  heterocycle,   led  us  to test the  sedative
thalidomide.  It  was toxic  for Ochromonas danica
0. malhemensis  and  Tetrahymena pyriformis; this
toxicity was annulled by nicotinic acid (or nicotina-
mide) or vitamin K (menadione) (Frank et al., 1963).
We do not know whether a  similar protection could
have  been  conferred  on human embryos  or poly-
neuritis in the adult.

   Many widely used  herbicides of the dinitrophenol
type are powerful poisons for higher animals.  We
do not  know  how sensitive protozoa would be for
detecting their persistence.   However, since some-
what similar thyro-active  compounds can be sensi-
tively  detected by   their  exaggeration  of  the &i%
requirement of Ochromonas malhamensis (Baker et
al.,  1961),  this  flagellate  might be a  useful test
object for dinitrophenols and congeners.

   The  Paramecium  (and perhaps too the Tetrahy-
mena)   test for polynuclear  benzenoid  carcinogens
has  remarkable  sensitivity  and specificity  (Epstein
and Burroughs, 1962; Hull, 1962). This test depends
on the carcinogen-sensitizedphotodynamic destruction
of paramecia by ultraviolet light.   This test is ap-
proaching practicality for air, and there is no reason
to suppose it  cannot  be  applied to benzene  extracts
of foodstuffs and water.
                  CONCLUSIONS


   We  have suggested here new procedures for ex-
amining  the  intrinsic toxicity-persistence relation-
ship, using as test organisms the protists represented
conspicuously in  a  Winogradsky column.  The new
field of  micro-toxicology is virtually undeveloped.
The  urgent need  for  detecting  chronic,  low-grade
toxicities is evident from many sides.   This is not
the place  for  a detailed discussion of the medical
implications  of  this  area of research, but it should
be emphasized  that chronic toxicities and carcino-
genesis  are  related.   Conversely, Umezawa  (1961)
has remarked that most antitumor substances have
chronic  toxicities and that  elaborate  testing proce-
dures  for toxicity  are  required  to fix  the  daily
tolerable dose;  apparently this  problem is a central
theme  in  medical  as  well as  pollution research.
Inhibition of growth of an array of protozoa is now
in practical use as  a  means of detecting anticancer
substances in antibiotic beers (Johnson et al.,  1962).
   Since the  embryos  appear to lack the detoxication
mechanisms  of  the  adult  animal (Brodie,  1962),
toxicity for  protozoa  (which presumably lack these
detoxication  mechanisms)  should be compared with
that  for the embryo, not the adult, as emphasized
by the thalidomide disaster.


   There are further limitations on the use of microbes
as detectors of toxicity.  High-molecular toxins seem
inert to microbes, and antihormones (with the excep-
tion  of anti-thyroid compounds) are generally inert.
The  main usefulness  of  microbial indices of toxicity
would appear, then, to be for detecting low-molecular
poisons acting on  cellular  targets rather  than  on
cell  systems and organs.   These  are precisely the
poisons likely to put out  of  business  a pollution-
control installation primarily dependent on microbial
activity.
                                             REFERENCES
Aaronson,  S.  and Bensky, B.  1962. Protozoological
studies  of the cellular  action of drugs.  I. Effect of
1-aminoc^cZopentane-l-carboxylic acid and 1-amino-
S-methylcycZo-hexanel-l-carboxylic  acid on   the
phytoflagellate Ochromonas danica. Biochem. Phar-
macol. 11: 983-6.
Aaronson, S., Bensky,  B., Shifrine, M. & Baker, H.
1962. Effect of hypocholesteremic agents on protozoa.
Proc. Soc. Exptl. Biol. Med. 109: 130-2.

Alexander,  M.  1961.   "Introduction to Soil  Micro-
biology",  John  Wiley  &  Sons,  N. Y.  (see  p.  240).

Baker,  H.,  Frank,  O.,  Hutner, S. H.,  Aaronson,
S.,  Ziffer,  H.  and Sobotka, H.  1962.   Lesions in
folic acid  metabolism  induced by primidone.   Ex-
psrientia 18: 224-6.

Baker,  H.,  Frank,  O., Pasher, I., Ziffer, H., Hutner,
S. H. and  Sobotka, H.  1961.   Growth inhibition of
microorganisms by thyroid hormones.  Proc. Soc.
Exptl. Biol. Med. 107: 965-8.
Berger, B. B. 1961. Research needs in water quality
conservation.   In  "Algae  and Metropolitan Wastes",
Trans.  1960 Seminar,  Robt. A. Taft Sanitary Eng.
Center, Cincinnati 26, Ohio,  p. 156-9.

Brodie, B.  D.  1962.  Drug metabolism-subcellular
mechanisms.  In "Enzymes  and  Drug Action", J. L.
Mongar and A. V. S. de Reuck, eds., Ciba Foundation
Symposium,  J.  & A.  Churchill Ltd.,  p.  317-40.

Eppley,  R. W.  and  MaciasR, F.  M.  1962.  Rapid
growth  of  sewage lagoon Chlamydomonas with ace-
tate.  Physiol.  Plantarum 15: 72-9.


Epstein, S. S. and Burroughs, M.  1962.  Some factors
influencing the photodynamic response of Paramecium
caudatum to 3,4-benzypyrene,   Nature 193:  337-8.


Frank,  O.,  Baker, H.,  Ziffer, H,, Aaronson, S., and
Hutner, S. H. 1963. Metabolic deficiencies in protozoa
induced by Thalidomide.  Science 139: 110-1.

-------
 48
ENVIRONMENTAL REQUIREMENTS OF FRESH-WATER INVERTEBRATES
 Hawkes,  H. A.  1960.   Ecology of activated  sludge
 and bacteria beds.  In "Waste Treatment", P. C. G.
 Isaac,  ed., Pergamon, N. Y., Oxford, etc., p.  52-
 97; discussion p.  97-8.

 Holz,  G.  G.,  Jr., Erwin,  J.,  Rosenblum,  N. and
 Aaronson,  S. 1962.   Triparanol inhibition of Tet-
 rahymena and its prevention of lipids. Arch. Biochem.
 Biophys.  98: 312-22.

 Hull, R.  W. 1962.  Using the "Paramecium assay"
 to  screen  carcinogenic  hydrocarbons.   J. Proto-
 zool. (Suppl.) 9: 18.

 Hutner, S.  H. 1962.  Nutrition of protists.  In "This
 is  Life:  Essays in Modern Biology", W. H. Johnson
 and W. C.  Steere,  eds., Holt, Rinehart and Winston,
 N. Y., p.  109-37.

 Hynes,  H.  B.  N. 1960.   The  Biology of Polluted
 Waters.  Liverpool Univ. Press.

 Johnson,  I. S., Simpson,  P.  J.  and Cline, J. C.,
 1962.   Comparative  studies with chemotherapeutic
 agents in biologically diverse in vitro cell systems.
 Cancer Research 22:  617-26.

 Leighton,  P. A.  1961.   "Photochemistry of Air
 Pollution",  Academic Press, N. Y.

 Miller, J. A., Wyatt,  C.  S., Miller, E. C. and Hart-
 man, H.  A. 1961.   The N-hydroxylation of 4-ace-
                                     tylamino-biphenyl by the rat and dog and the strong
                                     carcinogenicity  of N-hydroxy-4-acetylaminobiphenyl
                                     in the rat.  Cancer Research 21: 1465-73.

                                     Provasoli, L. 1961. Micronutrients and heterotrophy
                                     as  possible  factors  in bloom production in natural
                                     waters.  In "Algae and Metropolitan Wastes", Trans.
                                     1960  Seminar,  Robt.  A.  Taft Sanitary Eng. Center,
                                     Cincinnati 26, Ohio, p.  48-56.

                                     Ross,  W. K. and Sheppard, A. A. 1956.  Biological
                                     oxidation  of  petroleum  phenolic  waste waters.  In
                                     "Biological   Treatment  of  Sewage  and Industrial
                                     Wastes",  J.  McCabe  and W. W.  Eckenfelder, Jr.,
                                     eds.,  1: 370-8. Reinhold Publ. Co., N. Y.

                                     Scher,  S., Scher, B.  and Hutner,  S. H.  1963. Notes
                                     on  the  natural history of Rhodopseudomonas palus -
                                     tris.  In "Symposium on Marine Microbiology", ed.
                                     C.  H. Oppenheimer, C. C.  Thomas, Springfield, 111.,
                                     p. 580-7.

                                     Umezawa,  M.  1961.   Test methods  for antitumor
                                     substances.  Sci.  Repts. 1st. Super. Sanita 1: 427-38.

                                     Zahalsky, A, C., Keane,  K., Hutner, S. H., Kittrell,
                                     M,  and Amsterdam,  D.  1962.  Protozoan response
                                     to  anticarcinogenic heterocyclic N-oxides:  toxicity
                                     and temporary  bleaching.   J.  Protozool.  (Suppl.)
                                     9: 12.
               THE ENVIRONMENTAL REQUIREMENTS OF  FRESH-WATER PROTOZOA

                                            John Cairns, Jr.*
   In "A  Study of Some Ecologic Factors Affecting
the  Distribution  of  Protozoa," Lackey (1938) dis-
cussed  much of the  existing literature regarding the
environmental requirements of the Protozoa and pre-
sented some thoughts  of his own  based upon an ex-
tensive  series  of   species  determinations  from  a
variety  of  habitats.  It is not my intent to  review for
this brief presentation the literature bearing on this
subject  between  1938  and 1962, but merely to call
attention to the fact that no major change  in thinking
has developed in this interval.

   Most protozoologists agree that fresh-water Proto-
zoa  have  a truly cosmopolitan distribution.  For
example, Bovee (1957) notes  the similarity  between
populations of Protozoa in the Savannah River Basin
in North  America  and the  Amazon Basin in South
America.   However, the most convincing indication
of cosmopolitan distribution is the free and success-
ful  use of  keys  to  species,  such as those of Kahl,
Pascher, Gojdics, or Skuja, in all parts of the world.
Despite the possibility that a particular species might
occur  in  any  part  of the  world, there  is general
recognition that  it  will do  so only  when  specific
environmental  conditions exist.  These  conditions
may cover a wide  range  for certain species  such
                                      as  Stylonychia mutilis  (Muller), which occurs  in
                                      fresh, brackish,  and salt  water; or  may  be quite
                                      narrow as is apparently the case iorStokesiavernalis
                                      Wenrich, which appears only rarely and under almost
                                      identical  conditions.   Thus,  the frequency of oc-
                                      currence  may vary from a single record for  many
                                      species  to an almost monotonous regularity  for a
                                      few species.   Even the most ubiquitous species may
                                      be dominant in a protozoan population for a relatively
                                      short  period  of  time  as  shown by  Wang (1928),
                                      Bamforth  (1958),  and  others.   Thus,  in  a natural
                                      environment constant replacement of the component
                                      species  of a protozoan community is a normal event.
                                      There is ample evidence that this succession is due
                                      not only to variations in pH, dissolved oxygen  con-
                                      centration, temperature,  and the like, but also to the
                                      direct  effect  of  one species upon  another.    This
                                      interaction includes  competition, predation, and the
                                      production  of substances  by a  species necessary
                                      for the growth of another or which repress the growth
                                      of another.

                                         Although it is  evident that  at  least some species
                                      may acclimate to conditions beyond  their  normal
                                      range  of tolerance (Dallinger,  1887;  Finley,  1930;
                                      Lackey,  1938; and others), it has not been established
  Curator, Department of Limnology, Philadelphia Academy of Natural Sciences, Philadelphia, Pennsylvania.

-------
                         The Environmental Requirements of Fresh-Water Protozoa
                                               49
that this may be accomplished in the face of the com-
petition  and  changing environmental  conditions in
normal streams  or  lakes.  However, individual Pro-
tozoa  may  be found  in  all sorts  of  environments
from hot springs to snow banks indicating effective
natural selection over long periods of time.  It is
also  evident that certain environments may  contain
only  comparatively  few  species  while others may
contain an impressive  diversity of species  suggesting
that optimum environmental conditions are also opera-
tive at the population  level.  Since present svidence
indicates that it  would be both impossible and un-
desirable to satisfy the environmental requirements
of  specific  protozoans under  natural  conditions, it
appears  that the best  means of determining whether
or  not  the  environmental requirements  of fresh-
water species are  being met is  by evaluating  the
entire protozoan  community   (in  the  general sense
of the term rather than the restricted use implying
a fixed association of species) and the environment
in which  it  occurs.   The three most commonly used
means  for  such evaluation are (1) use of indicator
species according to a saprobic system, (2) by quan-
titative determination  of the density of organisms, (3)
by  determining the diversity of species.  Ironically,
the assumption is often made  that one must choose
between the various means of evaluation rather than
use every means available. Obviously use of  several
criteria provides a firmer base  for  evaluating an
effect than does  use of a single one.  This comment
is not intended as a criticism of formal systems of
evaluation, but only of  the rigid use of a single system.

   Many species of protozoans are excellent indicators
of specific  conditions. Information of this type from
both field observations and laboratory cultures is con-
stantly furthering our  ability  to  characterize  an
environment from the nature of the species inhabiting
it.  On the other hand, the requirements of the majority
of species commonly  encountered in fresh water are
not clearly defined.

   In order  to outline the  problems existing in  the
characterization  of  protozoan populations and their
environments,  an  analysis has been  made of  the
results obtained  by  the Academy of Natural Sciences
of  Philadelphia river-survey team.  The  data were
obtained from a series of  202 areas in various rivers
and streams  mostly  in  the United States, but in a
few cases from other parts  of  the  world.  All of
these  areas were classified  as healthy  or  semi-
healthy according to the system described  by Patrick
(1949, 1950).   Although  most of the sampling took
p^.ace in the spring, summer,  and fall, a  number of
winter  samplings are included in this total. Each
sampling area included  approximately 100  to   300
yards of stream or  river from bank to bank, and
commonly included a  riffle, slack water,  and a pool
area.  Collections were obtained in the  morning from
all  common habitats, such as algal  growths, mud
surfaces, submerged roots, etc., in both shaded and
sunlit areas,  and were placed in half-pint screw-top
jars  leaving  a half-inch  air space above the water
surface.  These  samples were immediately  carried
to  the  field laboratory where identifications were
made  from living specimens. Generally, about 20
half-pint samples were  collected, and approximately
a dozen different examinations were made from each
jar.   The samples were first examined under a low-
power lens  to determine the general structure of the
population.  More critical and detailed examinations
followed.  Most samples were taken from the meniscus
and the bottom of the jar both toward and away from
the principal source  of  light, although an effort was
made to insure that attached species (to twigs, leaves,
algal filaments,  etc.) were not overlooked.   Before
the sampling began, several concentration techniques
were tried and discarded because many species were
destroyed or injured  and many streams  had a  com-
paratively heavy  silt  load  which interfered with both
concentration  and examination.  Only those species
with  a  density of  at least  six individuals  or  more
per  drop  of water from  at least one sample were
recorded.  Furthermore, no samples of the  plankton
are included in this report, but only those species in
association  with  the substrate.  Nearly 1200 species
were identified*  in the course of these studies, of
which approximately  25  percent  occurred in four or
more of the  areas sampled. In other words, approxi-
mately 75 percent of the species occurred  in three
or less of  the  areas  sampled.   The 1200 species
represent only a fraction of those  described.   For
example nearly 6000  species of  ciliates alone, most
of which are free-living, have been described to date
according to Corliss  (1961, p. 23).  Three-quarters
of the 1200 species recorded  in this series of  samples
occurred  less  than 1.6 percent of  the  time.  For
virtually all of these species the significance of the
presence  or absence of a single  species would be
quite difficult to determine.  The inhabitants of a
number of the areas studied were classified according
to their saprobian designation when this was known.
For  many of these species no information was avail-
able.   For those  species with specific saprobian
designation, some sampling areas had excellent agree-
ment in species  composition, although the greater
number did  not.   In short, for species which are rare
or uncommon, present information does not always
permit accurate designation of overall environmental
qualities either on the basis  of single species occur-
rence or groups of species.

   There  remains  to  be considered the 25 percent
of the species which  occurred four or more  times
in the 202  areas sampled.   Of these,  only  20, or
roughly 6  percent,  of  those found  four or   more
times occurred   in at least  25 percent of the areas
studied.  The number of areas in which each of these
20 species occurred  was as follows: 125, 87, 80, 69,
67, 66, 64,  64, 62, 60, 60, 60, 55, 53, 52, 49, 49, 48,
47, 47. Naturally these ubiquitous species occurred
together  quite  often.   In  an  effort to  determine
whether or  not pairs of these species occurred to-
gether more frequently  than would be expected from
chance  alone, an association matrix was made for
the 20  sampling areas  where  these species  were
most common.  A Chi-square test of significance was
run on the 190 possible associations of species pairs,
and of these, 44  occurred together  more frequently
than  expected from  chance  alone at the 5 percent
level of  confidence.   Also, when the  Chi-squares
for  all of  the paired associations  were summed,
*0ver half of the identifications were made by the authors; the remainder were made by Drs. Mary Gojdics, Ralph Wicterman
 Samson McDowell, Jr., Stuart S. Bamforth, and J. Russell Gabel.

-------
50
ENVIRONMENTAL REQUIREMENTS OF FRESH-WATER INVERTEBRATES
the  result  showed a  highly  significant  divergence
from chance  expectation.   Comparison  of  the  ex-
pected and observed frequency distributions of Chi-
square  values showed that the divergence was  due
to the  aforementioned large  number of significant
associates at  the 5 percent level of  confidence.  An
examination of  the  data indicated that associations
of three  or more  species also  existed.  The fact
that  these species were able  to  occur together sug-
gested similar environmental requirements and that
the environment might be the  major factor producing
these associations.   To  check  this  possibility  the
environmental data were processed with a computer
and information was obtained  for each of the 20 most
common species throughout the entire  series of  oc-
currences.  An example of the grouping of this infor-
mation  for a single  species is given in Table 1.
Note that species  number  42000 occurred 86.11 per-
cent of  the time within the phenopthaline alkalinity
range  of 1.0  to 5.0 ppm, and that the pH range for
97 percent of the  records was between 6.5 and 9.0.
When the  results for  the  20  most common species
were compared, three factors were noted:  (1) pairs
or larger groups of associated  species  always  had
virtually identical ranges of environmental conditions;
(2) these species always tolerated rather broad ranges
of environmental conditions; and (3) having identical
ranges  of tolerance to  the   chemical  and physical
environment does not  insure that species  will be
associated more often than would happen by  chance
alone, since only 44 pairs  out of  190 were associated
significantly despite the  fact that all  species  had
broadly overlapping environmental ranges.  In fact,
three  cases of negative association were found  and
in each  case the environmental characteristics were
almost  identical.   Since  only the general environ-
mental  characteristics were determined, it  must be
assumed  that competition or materials present in
extremely low concentrations may often be critical
in these negative associations or  that  the low number
occurring  in  this series  was due to chance alone.

   At this point,  a consideration of  the relation of
the sampling method to the results is essential. The
most important factor  is probably the omission of all
species below the required density.  Unless several
protozoologists were to work on a single sample at
the  same  time, identification of these low density
species would be impractical because no preserva-
tion  method is suitable for the entire community  and
the  structure of the community  in the unpreserved
sample jar changes due to death and division.  The  low
density species  may be (1) a species  formerly abun-
dant but  now in declining numbers, (2) a  species
increasing  in  abundance  but not yet  of sufficient
density to be  recorded,  (3) a species that has per-
sisted at a low  population density for a considerable
period of time. The first may have produced metabolic
products or other substances which affect the popula-
tion  size of the second or vice  versa.  The second
most important  factor is probably species with  low
densities of large size individuals which may repre-
sent a  greater  mass  of protoplasm than a  small
species with a sufficient number of individuals to be
recorded.   For  example, a single  Spirostomum
ambiguum has a volume equal  to many Bodo caudatus.
                                    Perhaps  an extension of the system proposed by
                                    Sramek-Husek (1958) would permit weighting of these
                                    size differences. It would then be possible to determine
                                    the relative importance of the quantitative and quali-
                                    tative relationships between species.

                                       Thirdly, samples  of water for chemical  analysis
                                    were usually composited from several points in each
                                    sampling area.   Thus, they represent the  macro-
                                    chemical-physical environment of the protozoan popu-
                                    lation but not the microenvironment  for each com-
                                    ponent species.

                                       The  importance of low density species as reserve
                                    components has  also been demonstrated by  Wallace
                                    (in Cairns,  1956), who has shown that variation in
                                    temperature will alter the structure of a mixed algal
                                    population  consisting of diatoms, greens, and blue-
                                    greens.  She has further shown that increased tempera-
                                    ture will result  in a dominant blue-green population
                                    although originally these algae  represented  a minor
                                    portion of the population. In addition, the diatoms,
                                    although  virtually absent when the  blue-greens  are
                                    dominant, again  became dominant when the tempera-
                                    ture  was  lowered to a range favorable to them. It
                                    is quite  probable that large numbers of  species of
                                    Protozoa in a natural environment at low densities
                                    form the  reserve  components which make  possible
                                    and perhaps, in  some cases, even cause the  constant
                                    shifts in dominant  species  composition  which  are
                                    typical   of  a  natural  fresh-water  protozoan com-
                                    munity.   Thus,  parameters  for  the environmental
                                    requirements  of fresh-water  Protozoa should  take
                                    into  consideration  both the  existing community of
                                    species, with comparatively large numbers of individ-
                                    uals  per unit volume, and  also  those species  with
                                    relatively few numbers of individuals.

                                       Although the species composition may  vary con-
                                    stantly,  Patrick  (1961) has shown that the number of
                                    collectable taxa of  the various major  groups of
                                    aquatic organisms (including Protozoa) remains rea-
                                    sonably  similar. More  specifically, the  number of
                                    taxa  usually  does  not vary  more  than  33  percent
                                    from the  mean for that  group.   Patrick states,
                                    "Perhaps the reason for this similarity of numbers
                                    of taxa  of a  group  of organisms in these  areas of
                                    natural  streams is  because there are a finite and
                                    similar  number of  habitats  or  niches for  species
                                    occupancy.    The numbers of taxa which  are avail-
                                    able  to  live in the area under consideration  are
                                    greater   than  the  number  of  niches."  Thus, as
                                    environmental conditions  change, new  species  are
                                    able  to  compete  successfully  with the  dominant
                                    species occupying niches  and in turn become dominant
                                    only to be replaced with the next change in  conditions.

                                       To establish  the  environmental requirements of
                                    fresh-water Protozoa, the following  factors appear
                                    to  be  of  primary  importance:   (1) chemical and
                                    physical  standards  would either be so  broad  that
                                    they  would  be meaningless  or  else they would be
                                    inapplicable in  view of  the wide regional variation
                                    in these  characteristics  of fresh water and  even in
                                    the  seasonal variation of a  single stream;  (2)  con-
                                    stant replacement of  both species and entire protozoan

-------
The Environmental Requirements of Fresh-Water Protozoa
51
Table 1.
SPECIES NUMBER 42000
RANGE 0
ALKALINE P
RANGE 0
ALKALINE MO
RANGE 0
CHLORIDE
RANGE 0
C02

D.O.

FE


RANGE 0

RANGE 0

RANGE 0
1.0
5.0
1
1.0

1.0

.01
18.18
5
5.0
86.11
10.0
1.45
3
8.70
5.0
40.00
3.0
3.17
.03
12.12
10
HARDNESS

Ca

Mg

NH3-N

N02-N

N03-N

pH

P04

Si02

so4

RANGE 0

RANGE 0

RANGE 0

RANGE 0

RANGE 0

RANGE 0

RANGE 0

RANGE 0

RANGE 0

RANGE 0
3
5.80
3
18.84
.001
18.57
.001
13.85
.001

3.0

.001
2.86
.001

1
2.90
4.0
10
11.59
10
23.19
.009
8.57
.007
60.00
.007
2.86
4.5

.005
12.86
.01

10
20.29
12.0
TEMPERATURE

RANGE 0
TURBIDITY

B.O.D.

TOTAL

TOTAL
RANGE 0

RANGE 0
P
RANGE 0
N
10
13.04
.1
12.00
.06

.001

25
26.09
.5
18.00
10.0

.01

10.0
5.56
20.0
5.80
5
10.14
10.0
60.00
5.0
6.35
.05
6.06
50
18.84
30
27.54
30
39.13
.03
25.71
.013
12.31
.013

5.0
1.45
.01
7.14
.05

30
37.68
17.0
3.08
50
20.29
1.0
16.00
25.0

.02

20.0
2.78
30.0
10.14
10
14.49
20.0

7.0
15.87
.07
12.12
100
24.64
50
31.88
50
7.25
.05
11.43
.03
1.54
.03
5.71
5.5

.05
25.71
.1

60
23.19
20.0
13.85
100
36.23
5.0
34.00
OVER

OVER

40.0
40.0
8.70
50
43.48
30.0

9.0
44.44
.1
9.09
150
7.25
75
15.94
75
8.70
1.0
28.57
.07
7.69
.07
14.29
6.0

.1
21.43
.5
1.45
90

23.0
26.15
500
4.35
10.0
8.00




PERCENTAGES
80.0
5.56
50.0
4.35
100
10.14
40.0

11.0
28.57
.4
15.15
200
26.09
100
4.35
100
1.45
10.0
4.29
.2
1.54
.2
50.00
6.5
2.90
.5
17.14
1.0

120
2.90
28.0
47.69
1000

20.0
10.00




160.0
100.0
44.93
500
1.45
50.0

15.0
1.59
.7
21.21
500
18.84
200
2.90
200
1.45
20.0
1.43
1.5
3.08
.7
15.71
7.5
34.78
1.0
1.43
3.0
10.14
240
7.25
30.0
3.08
2500

40.0
2.00




320.0
150.0
11.59
2500
10.14
75.0

18.0

1.0
6.06
1000
4.35
450

450

40.0

3.0

1.5
5.71
8.0
33.33
5.0
5.71
6.0
31.88
480
4.35
35.0
1.54
5000

80.0





OVER
200.0
8.70
10000
1.45
100.0

20.0

5.0

2500

1000

750

60.0
1.43
7.0

3.0
4.29
9.0
26.09
10.0

12.0
40.58
960
1.45
40.0

7500

OVER





550.0
4.35
15000
200.0

OVER

10.0

5000

2000

1000

OVER

OVER

7.0
1.43
9.5
1.45
OVER
5.71
48.0
15.94
1500

OVER
4.62
10000







TOTAL
100.0
OVER TOTAL
100.0
OVER TOTAL
100.0
OVER TOTAL
100.0
TOTAL
100.0
OVER TOTAL
100.0
OVER TOTAL
100.0
OVER TOTAL
100.0
OVER TOTAL
100.0
TOTAL
100.0
TOTAL
100.0
OVER TOTAL
100.0
OVER TOTAL
100.0
TOTAL
100.0
OVER TOTAL
100.0
OVER TOTAL
100.0
TOTAL
100.0
OVER TOTAL
100.0
TOTAL
100.0
TOTAL
100.0
TOTAL
100.0

-------
 52
                 ENVIRONMENTAL REQUIREMENTS OF FRESH-WATER INVERTEBRATES
communities is the rule rather  than the exception;
(3)  the  large  species reservoir which  exists in in-
active stages  or  in active stages below the  popula-
tion density, easily detectable by the usual examina-
tion techniques, is necessary for the constant replace-
ment of species;  (4)  a  limited number of niches is
available  in natural  stream situations resulting in
intense competition  and  constant  replacement  of
species  with   shifts  in the chemical  and  physical
environment.

   The  requirements of Protozoa may be stated  as
those  conditions  which  permit the  protozoan popu-
lation to remain within the range of species diversity
found to be normal for the environment in question.
Obviously, considerably more data will be required
before the normal range or variation for the various
types of aquatic environments  becomes  reliably es-
tablished.  Furthermore, since Protozoa are part of
a larger aquatic  community  one should evaluate this
first, together with the general  chemical and physical
environment, before proceeding to any specific group
evaluation.  These multiple lines  of  evidence would
thus provide  a  much firmer basis for  determining
the degree to which the requirements of the aquatic
biota are being met.

              ACKNOWLEDGMENTS

   The  author is  indebted to  Dr.  Keith  Justice for
his advice and  help with the statistical portion of
this paper,  and  to  Messrs.   Jerry Feldman  and
Cristopher Matthews for assistance  in  processing
the data.
                                             REFERENCES
Bamforth,  S.  S. 1958.   Ecological  studies on  the
planktonic protozoa of a small artificial pond. Limnol.
Oceanog. 3 (4): 398-412.

Bovee,  E.  C.  1957.  Protozoa of Amazonian  and
Andean waters of Colombia, South America. J. Proto-
zool., 4: 63-66.

Cairns, J.,  Jr.  1956.  Effects of increased tempera-
tures  on  aquatic organisms.  Industr. Wastes,  1
(4): 150-152.

Corliss, J.  O.  1961.  The Ciliated Protozoa. Perga-
mon Press.  310 p.

Dallanger,  W.  H. 1887.   The President's address.
J. Roy. Micr. Soc., p.  185-199.

Finley, H.  R.  1930.   Toleration  of  fresh-water
protozoa to increased  salinity.   Ecology, 11  (2):
337-347.

Lackey,  J.  B.  1938.    A study  of  some ecologic
 factors affecting the distribution of protozoa. Ecol.
 Mongr., 8 (4): 501-527.

 Patrick,  R. 1949.   A proposed biological measure
 of  stream  conditions based  on  a  survey of the
 Conestoga  Basin,  Lancaster County, Pennsylvania.
 Proc. Acad. Nat. Sci. Phila., 101: 277-341.

 Patrick, R.  1950. Biological measure of stream con-
 ditions.  Sewage and Industr. Wastes,  22: 926-938.

 Patrick, R.  1961. A study of the numbers  and kinds
 of  species  found in rivers in eastern United States.
 Proc. Acad. Nat. Sci. Phila., 113: 215-258.

 Sramek-Husek,  R. 1958.   Die  rolle der ciliaten-
 analyse bei der biologischen kontrolle von fluss-
 verunreinigungen.    Verh.  int.  Ver. Limnol.,  13:
 636-645.

 Wang,  C.  C.  1928.   Ecological studies  on the sea-
 sonal distribution  of protozoa in a fresh-water pond.
 J. Morph.,  46:  431-478.

-------
                     Relations of Planktonic Crustacea to Different Aspects of Pollution
                                                                                                     53
          RELATIONS OF PLANKTONIC CRUSTACEA TO DIFFERENT ASPECTS OF POLLUTION

                                         Dr. Jaroslav Hrbacek*
   In 1909, Kolkwitz and Marson classified the pol-
 lution of waters  into saprobiological zones (reported
 by  some  succeeding authors as saprobiological de-
 grees).   They  supposed that various saprobiological
 zones differ by  the extent to which organic  matter
 that is  introduced by pollution is mineralized. They
 considered,  for  example,  Daphnia pulex de  Geer,
 D. magna  Straus,  and D.  longispina  O. F.  Muller
 as  b-mesosaprobic  (to some  extent  also <-meso-
 saprobic),  Daphnia hyalina Leydig with the  ssp. D.
 h. galeata  Sars,  and Daphnia  cucullata Sars with all
 its  varieties,  as  oligosaprobic.    They regarded
 Bosmina  longirostris  Muller as both oligosaprobic
 and  as  0 -mesosaprobic.   From this it  follows that
 most of the  species can develop in different sapro-
 biological  zones, so that  the  proper use  of these
 animals as  indicators  depends more or less  upon
 experience.   Zelinka,  Marvan, and Kubicek (1959)
 developed a  more objective procedure, the principle
 of which can be  explained by the following example.

   Table 1 shows the saprobiological values of dif-
 ferent species  of Cladocera.  For  example, Daphnia
magna has the value 4 in  the °<-mesosaprobic zone
 and the value 6 in the polysaprobic zone. (The sum
 of the values of  all  zones  is, for  each species, 10.)
 The  saprobiological evaluation of  a sample  from a
pond  in Table 2 is performed by  expressing the
frequency  of the species in the sample in absolute
 numbers or  in relative ones  (in  percents), and by
 multiplying the  frequency by  the saprobiological
values  in  question.   In this way we find the sum of
these products in the different saprobiological zones.
 The  sample in question is classified into the sapro-
biological  zone that possesses the  greatest sum.  If
 some doubt arises, then greater weight is attributed
to species  occurring in their proper frequency (indi-
 cated in numbers according to the Braun-Blanquet
scale in the last column of Table 1).
                     But  even if this  procedure is used,  uncertainty
                   remains in  regard to the objective  measure of the
                   individual  zones by  the  presence of the  chemical
                   substances.  The BOD  and COD are  most commonly
                   used as chemical measures  of pollution.  However
                   when comparing bodies of water in which there was
                   a twofold  difference in  mean BOD and COD, we
                   could not  find  a definite difference in zooplankton
                   composition.  The most common Cladocerans in the
                   plankton,  both in Horejsi pond in 1957  and Klicava
                   reservoir  in 1960, viereBosmina longirostris Muller,
                   Daphnia cucullata Sars, Daphnia  longispina Muller,
                   Diaphanosoma  brachyurum (Lievin) and Ceriodaphnia
                   pulchella (Sars). The mean BOD of the surface water
                   of the pond was 7 and of the reservoir 2 milligrams
                   per  liter O2Vy In 1960, the COD of the surface water
                   from the  Klicava reservoir was  12.8 and from the
                   Slapy reservoir, with practically  identical composi-
                   tion of  zooplankton, 48 milligrams per liter 02. On
                   the  other  hand, Daphniapulex de Geer prevailed in
                   ponds where the BOD and COD of the surface water
                   were intermediate between these extremes (the mean
                   BOD of these ponds  ranged from 3.3 to 3.9 and the
                   COD from 25.2  to 29.8  milligrams per liter  O2).
                   This would imply that neither of these properties is
                   directly related to any selective factor that could be
                   responsible for the different development of plankton
                   in Crustacea.   This makes it necessary to review
                   the  findings on the  influence of different injurious
                   polluting substances  upon the different  species  of
                   zooplankton.

                     One  of the most investigated aspects  is the effect
                   of the low  oxygen content upon zooplankton. In lakes
                   with a clinograde oxygen curve,  with a  strong defi-
                   ciency  of  oxygen  in the hypolimnium, planktonic
                   crustaceans are frequently observed in samples with
                   only a  few tenths of milligram per liter of oxygen.
                   It is probable that the cladocerans observed are not
                Table 1. EVALUATION OF THE OCCURENCE OF PLANKT. CLADOCERA IN
                          SAPROBIOLOGICAL ZONES (Zelinka and others,  1959)	
                                                        Saprobiological zones
Species
Bosmina longirostris (O.F.M.)
Ceriodaphnia pulchella Sars
Daphnia cucullata Sars
Daphnia longispina O.F.M.
Daphnia magna Straus
Daphnia pulex de Geer
Diaphanosoma brachyurum Liev
bos
1
1
+
1
-
-
+
aos
4
4
4
2
-
-
5
bms
4
5
6
4
+
+
5
ams
1
-
-
3
4
5
-
ps
_
-
-
-
6
5
-
hs
_
-
-
-
-
-
-
frequency
5
4
4
5
5
5
4
   bos = beta-oligosaprobic zone
   bms = beta-mesosaprobic zone
   ps  = polysaprobic zone
aos = alpha-oligosaprobic zone
ams = alpha-mesosaprobic  zone
hs  = hypersaprobic zone
 Czechoslovak Academy of Science.

-------
54
ENVIRONMENTAL REQUIREMENTS OF FRESH-WATER INVERTEBRATES
living  under these conditions  for a long period of
time, because they do not exhibit the red color that
has  been noted in specimens from very productive
ponds, where,  throughout some periods, low  con-
centrations  of oxygen occur, especially during night
hours.  Fox (1951) and his collaborators have shown
that this  color  is  caused by hemoglobin, which in-
creases  the  survival  time  of Daphnia species in
semianaerobic conditions.

   In  small ponds, where,  under the  ice cover in
winter, the  concentration of oxygen drops to zero,
and sometimes  even hydrogen-sulphide is present in
concentrations up  to several milligrams per liter,
only some species of Cyclopidae,  for  example,  Cy-
clops viridis  (Jurine) and Cyclops strenuus (Fisher),
have been recorded  (Prokesova, 1959).  Under such
conditions, the species cannot develop until the moment
when,  after the disappearance of ice, oxygen appears
in the  water again.
                                     substances  for the destruction of  coarse fish, Clad-
                                     ocera are  reported to be  most  affected of all the
                                     zooplankton groups (Almguist , 1959).
                                        From this brief outline of effects of abiotic fac-
                                     tors, it  follows that, so far as is known, abiotic fac-
                                     tors  best  act  selectively  when  reaching extreme
                                     values.   This may  be inferred also  from data on
                                     distribution of some  species  as, for example,  of
                                     Daphnia pulex de Geer,  recorded both from  clear
                                     mountain lakes  above  the  limit of the  dwarf pine
                                     with  water  very poor in dissolved substances (Lity-
                                     nski, 1913) and from small village ponds with a very
                                     high  content of inorganic and organic matter (Langhans,
                                     1936; Wagler, 1937). It is to be pointed out, however,
                                     that  there  exist  waters  with intermediate positions
                                     where  not  a single specimen of Daphnia pulex can
                                     be observed—mountain  lakes,  for  example, below
                                     the limit of the  dwarf pine, that may lie in the same
                                     valley  as  do  lakes  where  Daphnia pulex has  been
                                     recorded (Litynski, 1913).
                            Table 2.  POND OSTROVEC U POZDATINA 26.7.1949
                                                                    Saprobiological zones
Species
Daphnia pulex de Geer
Daphnia magna Straus
Diaphanosoma brachyurium Liev

Frequency
in%
52
45
1

bos
_
-
-

aos
_
-
5
5
bms
_
-
5
5
ams
260
180
-
440
ps
260
270
-
530
hs
_
-
-
-
    bos = beta-oligosaprobic zone
    bms = beta-mesosaprobic zone
    ps = polysaprobic zone
                   aos = alpha-oligosaprobic zone
                   ams = alpha-mesosaprobic zone
                   hs = hypersaprobic zone
    A pH value  as low as 4.5 has been found in bodies
 of  water where the  planktonic  crustaceans were
 represented  only by  the genus  Ceriodaphnia.   In
 ponds  with  a  still  lower pH, Cyclopidae also  are
 rare or absent  and zooplankton is represented merely
 by  Rotatoria.  This low pH value may result not only
 from  pollution by  industrial  wastes, but  also from
 improper cultivation of the Norway spruce.  In three
 Bohemian mountain  lakes  of glacial origin where, at
 the end of the past century, a relatively  rich develop-
 ment   of  Daphnia longispina  and  Bosmina species
 occurred  (Fric and Vavra,  1898), none of the species
 mentioned has  been found at present.  The original
 beach  forest  was,  in the second half of the  last
 century, replaced by a Norway spruce monoculture,
 which  is said to acidify the soil.  Because  in the past
 century the pH of the lake water was not  measured,
 the low value  of pH recorded at  present cannot be
 proved to be merely of recent origin.  This could be
 done, however, in areas where the change in forest
 cultivation has  taken place quite recently.  K. Berg
 and I.  C. Petersen  (1956)  explain the disappearance
 of  Holopedium gibberum  Zaddach in  Lake  Gribs^
 in Denmark during the last century by similar events.

    Daphnia magna Straus is commonly used in tests
 for toxicity,  but, as far as is known, no differences
 in the  susceptibility to toxicants of different species
 have been investigated.  From  observations on lakes
 and ponds treated with insecticides and other toxic
                                        From this it may be concluded that the presence
                                     of  different  species  in different bodies  of  water
                                     depends on the biotic environment. To examine this
                                     possibility, two sets of experiments were  stated.

                                        One set, worked out to a great extent by Hrbackova
                                     (Esslova,   1962  and in press), consisted of cultiva-
                                     tions of individual  specimens  of  different Daphnia
                                     species  in  100-milliliter flasks,  daily  filled with
                                     about  50   milliliter  of water  enriched  with algae
                                     cultivated  in the  laboratory,  or with 50  milliliter
                                     of  surface  water  from  two  reservoirs.  The culti-
                                     vated specimens  were  measured  after  each molt.
                                     In the experimental series with surface  water from
                                     the Slapy reservoir, where about 0.1 milligram per
                                     liter  fresh weight of nannoplanktonic algae  and about
                                     10  milligram per liter fresh weight of blue-green
                                     algae (mainly Aphanizomenon) occured, three Daphnia
                                     species were examined: Daphnia pulex from a small
                                     village  pond  rich  in  nannoplankton,  Daphnia pulex
                                     from a  large pond poor in nannoplankton (according
                                     to  the  morphological features found to be identical
                                     with  Daphnia Forbes Hrbacek,  1959), and Daphnia
                                     hyalina  Leydig  from the Slapy reservoir.   Daphnia
                                     hyalina, in  addition to Daphnia cucullata, is common
                                     in the Slapy reservoir,  Daphnia pulicaria very rare,
                                     and Daphnia pulex has not been found up to the present.
                                     The  experiment  showed that  Daphnia pulex  cannot
                                     reproduce in the daily renewed Slapy water; the newly
                                     born  individuals,  thus kept, died after 3 to 4 molts

-------
                      Relations of Planktonic Crustacea to Different Aspects of Pollution
                                                                55
with symptoms of total exhaustion.  Daphnia puli-
caria and  Daphnia hyalina showed a slower growth
in the  Slapy  water as  well as a larger number of
molts to  maturity than did the control individuals,
which were kept  in  the Slapy  water, enriched with
laboratory-cultured Scenedesmus and Chlorella. The
slower  growth was in terms of the length increment
of each molt  and  also of the period from the release
of the young  individuals (the so-called neonatae) to
their maturity (the  so-called primiparae).    This
period was prolonged from the five days normal in
the  controls  to at least eight days with respect to
the experimental  individuals.  The smaller relative
increment  can be seen (Figure 1).  That  the  lower
increment is  caused  by the  low quantity of food, not
                 by its quality, is shown by the great improvement in
                 the growth of cultures  that were enriched about five
                 times with nannoseston by centrifugation (dotted line).
                 In experiments  with  Daphnia hyalina,  a  greater
                 variability has been observed, but the results were
                 the same.  The  average number of eggs, under ex-
                 parimental conditions, was recorded in Daphnia hya-
                 lina, namely  one-half of that found in Daphnia puli-
                 caria.  Daphnia pulex, when plentifully  fed, reached
                 maturity   by   about  one-tenth of the whole period
                 earlier than did Daphnia pulicaria.   In  the water of
                 another reservoir, which was about three times richer
                 in nannoplankton than the Slapy reservoir, the species
                 that first  reached maturity was  Daphnia longispina,
                 which does not occur in the reservoir itself. Daphnia



2.5-
2.0-

1.5 -

1.0-
-


_

-
0.5-
0.0
D. PULICARIA S.W.- SLAPY WATER CULTURE;
ON ABOUT 5 TIMES ENRICHED
C.N.- CULTURES
SLAPY WATER BY
SLAPY NANNOSESTON, ALG. CONTROLS CULTIVATED
IN SLAPY WATER ENRICHED WITH N ANNOPLANKTONIC
• ALGAE/SCENEDESMUS, CH LORELLA/FROM
/ LABORATORY CULTURES.
« Q ,--••'* .,.* '/

/* / / /''" .*''*
I H It/7
in//
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• :' Vl
° i'' •— • ALG.
o 	 o C.N.
E. ......
p.E.{£:ii kw.
L» 	 •-!
' ' ' 	 '











                                  D. HYALINA
                           2.0-
                           1.5-
                           1.0-
                           0.5
                            0.0
///.,
//   / f
I iff
                                     y/ J?'
                                                 :E:JALG-
                                                 .*:::-!i C.N.
                                                       s.w.
        Figure 1.  The logarithmic scale of the length is plotted on the Y-oxis, the number of molts on X-axis. Individual
                points indicate the average length of several individuals; full lines show the growth of the control
                individuals, broken  lines, the growth of the experimental individuals.

-------
56
ENVIRONMENTAL REQUIREMENTS OF FRESH-WATER INVERTEBRATES
pulicaria, Daphnia hyalina,  and Daphnia pulex  all
reached  maturity later.   From this it  follows that
the results  of both experiments do not  explain the
predominance of  Daphnia  hyalina in both reservoirs
as  caused by  food conditions; on the contrary, the
food conditions may be responsible for the exclusion
of some species.

   The relative increment, from neonatae to primi-
parae, under  both experimental and control condi-
tions, was found  smaller in Daphnia hyalina from
both reservoirs than in Daphnia pulicaria and Daphnia
longispina in  the experiments.   On examining the
relative increment of different species and different
clones at plentiful feeding at 20°  C (Hrbacek  and
Hrbackova,  1960),  it was found that species from
bodies of water  without  a fishstock  or with a low
one (for  example, D.  curvirostris and  D. pulicaria)
showed  invariably  larger relative increments than
did species  (for  example, D.  cucullata)  from bodies
of water with a numerous fish stock. In some species,
as in Daphnia hyalina and Daphnia longispina, clones
of  different  relative increments were  found from
bodies of water with different fish stocks.  We can
explain  the  predominance of Daphnia hyalina  and
Daphnia cucullata in both reservoirs by the assump-
tion that the fish stock is the main factor responsible.

   The other  set of experiments was performed on
small backwaters (Hrbacek, 1962) where stunted pop-
ulations  of  coarse fish occurred and where, of the
planktonic  cladocerans, Bosmina longirostris pre-
dominated, and the genus Daphnia was  represented
by  Daphnia  cucullata.  After the destruction of the
fish stock,  Bosmina  and Daphnia cucullata  entirely
disappeared  and  were replaced  by  populations of
either Daphnia hyalina  or Daphnia longispina.   The
most interesting experiment  of this set concerned
the destruction of the fish  stock from one  of the
backwaters of  about the same area, both drained by
the same periodic outlet from a village pond (Hrbacek
                                     et al., 1961).   The destruction of the fish took place
                                     in late summer of 1956, in the backwater nearer to
                                     the village  pond  called Poltruba.  The next year,
                                     Daphnia hyalina (exhibiting  large relative increments)
                                     predominated among the cladocerans in the Poltruba,
                                     whereas Bosmina longirostris was the leading species
                                     in the other backwaters.   It is  interesting that both
                                     the BOD  and   COD were  found invariably lower in
                                     backwaters without fish, where  Daphnia hyalina  oc-
                                     curred, although the renewal  of  the water was, at
                                     least  in  some periods, very  intensive, lasting at
                                     times merely  several  days, so that this difference
                                     cannot be  attributed to external factors.

                                        From  the above sets of experiments, it may be
                                     safely concluded that the  biotic  environment is  a
                                     selective  factor, promoting one species while sup-
                                     pressing  the others.   It  can be  assumed also that
                                     pollution,  in most cases, does not act  directly upon
                                     different  species  of  zooplankton,  but  that it does
                                     change  their  biotic  environment.   A part  of  the
                                     changes in zooplankton, attributed  to pollution, may
                                     be owing  instead to the changed nutritional level that
                                     results  from the development of bacteria or algae.
                                     Other changes  are owing to changes in the composi-
                                     tion  of  the fish stock,  since the oxygen deficiency,
                                     one of the most common  consequences of pollution,
                                     affects predators  more seriously  than  some species
                                     of coarse fish. If this is true, then the  situation may
                                     be improved, at least in some cases, by proper fish
                                     management, namely by  making the necessary  ar-
                                     rangements against  the  undesired propagation of
                                     coarse fish.

                                        From our experiments, the need seems to be for
                                     a more thorough knowledge of the physiological dif-
                                     ferences  among  species  and genera   that underlie
                                     the differences in their distribution.  Without this
                                     knowledge we  shall not succeed in giving a thorough
                                     explanation of the events observed, or our explana-
                                     tions will  be based on poorly defined factors.
                                             REFERENCES
Almquist,  E.  1959.  Observations  on the effect of
rotenone emulsions on fish food organisms. Report
No,  40:146-160,  Institute  of  Freshwater  Research,
Drottingholm.
Berg, K., and Petersen, L C.  1956.  Studies on the
humic acid lake Grobsjzi.  Folia limnol.  Scandinavica
No. 8. 273 p.

Fox,  H.  M.,  Gilchrist,  B,  M.,  and Phear,  E. A.
1951.  Functions of haemoglobin in Daphnia. Proc.
Roy, Soc. B., 138: 514-528.

Fric, A.,  andvVavra, V. j.898.   Vyzkum dvou jezer
sumavskychj Cerneho a  Certova jezera.  Arch, pro
prir. vyzk. Cech, 10(3)69 p.

Hrbacek,  J. 1959.  Uber die angelbliche variabilitat
von Daphnia pulex 1. Zool.  Anz. 162: 116-126.

Hrbacek,  J.  1962.    Species composition  and  the
amount  of the zooplankton in  relation  to the fish
stock.  Rozpravy  cs. akad. ved, Rada mat. a prir.
ved. 72  (10) 116 p.
                                     Hrbacek, J., Dvorakova, M., Koriiiek, V., and Pro-
                                     chazkova, L. Demonstration of the effect of the fish
                                     stock on the species composition of zooplankton and
                                     the intensity of  metabolism of  the  whole plankton
                                     association.   Verh.  Internat. Verein. Limnol., 14:
                                     192-195.

                                     Hrbacek, J., and Hrbackova-Esslova, M. 1960. Fish
                                     stock as a protective agent in the occurrence of slow-
                                     developing  dwarf  species  and strains of  the genus
                                     Daphnia.   Int. Revue ges. Hydrobiol., 45: 355-358.

                                     Hrbackova-Esslova, M. 1962. Postembryonic develop-
                                     ment  of cladocerans I. Daphnia pulex group. Acta
                                     Soc. Zool, Bohemoslov. 26: 212-233.

                                     Hrbackova-Esslova, M. (In press). The development
                                     of three Daphnia species  in the surface water of the
                                     Slapy  reservoir.  Int. Revue ges. Hydrobiol.

                                     Kolkwitz, R. and Marson, M.  1909.   Oekologie  der
                                     tierischen  Saprobien.   Int. Rev. ges. Hydrob. 2:
                                     126-152.

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                                       The Biology of the Tubificidae
                                                57
 Langhans, V.  1936.   Planktonorganismen als Indi-
 katoren  zur  beurteilung von Karpfenteichen.  Zschr.
 f. Fischerei u.d. Hilfswiss, 34: 385-399.

 Litynskl, A.  1913.   Revision  der Cladocerenfauna
 der  Tatrassen  I. Teil - Daphnidae. Bull. Acad. Sci.
 Cracovie, Cl. sci. math.-nat., sect. B, 1913, 556-623.

 Prokesova, V.  1959.   Hydrobiological  research of
two naturally polluted pools in the woody inundation
area of  the Elbe.   Acta Soc.  Zool.  Bohemoslov.
23: 34-69.

Wagler, E.  1937.  Crustacea, Krebstiere in Brohmer:
Die Tierwelt Mitteleuropas  2 (2).  224  p; Berlin.

Zelinka, M., Marvan, P., and Kubicek, F. Hodnoveni
cistoty  povrchovych vod. Opava 1959. 155 p.
            THE BIOLOGY OF THE TUBIFICIDAE WITH SPECIAL REFERENCE TO POLLUTION

                                            R. O. Brinkkurst*
   The title of this  paper is ambitious in view of the
present lack  of  information on the  biology  of the
aquatic oligochaetes.   Most of the  literature on
these worms  is  largely taxonomic, but owing  to a
good  deal of  confusion about valid characters and
no  recent revision,  it has  been difficult for ecolo-
gists to identify tubificids with any confidence.  Most
of the biological  data that are available refer speci-
fically to  Tubifex tubifexandLimnodrilushoffmeisteri
although I suspect that we  may not always place too
much reliance on the names used.  Having recently
attempted to   sort  out the  taxonomy  (Brinkhurst,
1963), I feel we are now in a position to point the way
to future  work on this family, which  will then be of
use  in the detection and assessment  of pollution of
various kinds  in inland waters.

   It  seems to me  that there are three basic ap-
proaches  to the  use  of macroinvertebrates in re-
lation to pollution (by which I mean not only pollution
by  organic  matter  but  also  the effects of  poisons,
inert solids, insecticides, and so on).  These I would
describe as: (1) the  establishment of physical-chem-
ical tolerance limits for individual species, (2) the
search for indicator species, the mere presence or
absence of which can be used to categorize the water
concerned,  (3) detailed analysis of community struc-
ture by  all available parameters,  including  biotic
and  abiotic factors,  consistent with the time, staff,
and  facilities available. My colleague, Dr. Hynes,
has  recently  published  a book  in  which the  third
approach  is dealt with in  detail, and he will show
how sensitive a tool  this can be in his address to this
symposium.   My own limited experience in the field
of river  pollution has  been as an  individual con-
sultant, usually working alone with access to  only
simple facilities  for chemical analysis.  In this work
I have found that an analysis of the bottom fauna of
a  series  of  stations  with  closely comparable sub-
strata gives a clear indication of the source, nature
and extent of  any "pollution" (if I may be allowed to
beg the question  of  a definition of that word). I now
wish to summarize  our knowledge of the Tubificidae
in relation to these three  approaches,  and I hope
that in so  doing  I  will have indicated the lines of
future research that  seem to me to be most profitable
to pursue.  I must here express my thanks to those
who  have supported my tour this summer (including
the Royal Society, The American Philosophical Society,
The  American  Society of  Limnology and  Ocean-
ography,  and,  not  least, Dr.  Ruth Patrick). From
this  tour  I hope to  lay the foundations of a taxonomic
revision of the North American species of the family.

1. The  tolerance  limits  of   individual  species to
factors  of the environment.

   The  first  difficulty encountered  in studying the
distribution  of the Tubificidae is that the numbers
of both  species  and individuals seem to vary in a
manner apparently  unrelated to any obvious chemical
or physical  factor.  Many  species occur in rivers,
streams,  pools,  and  lakes,  of  all sorts   and  all
conditions,  mostly  inhabiting  mud but demonstrat-
ing  no  clear habitat preferences.  The distribution
of species   in lakes  makes  no  sense in terms of
abiotic factors of the environment (as I  will illustrate
in a paper to be read  at the Limnological Congress
at Madison), and the same is true of worms collected
from rivers.  Very  different localities may, however,
support  surprisingly  similar populations.   As  an
example of  the absence of any  clear  pattern of the
abundance of  species in  relation  to substratum,
depth,   or emergent vegetation,  one  may  examine
Table  1.   As this represents  an analysis of sub-
samples of  up to  50 worms  from qualitative col-
lections,  we  can only regard these data as giving
a  rough estimate  of  the  abundance of the  species
at each station.    A second  survey,  carried  out 2
years later  by  C. R.  Kennedy  also  failed to find
any pattern in the  distribution of the worms, but did
find  that the relative abundance  of the species, ex-
pressed as  the percentage composition of the  total
worm population  from all samples, seemed remark-
ably  the  same as  that observed  in the first survey
(Table  1).   The same  species  were  collected (to-
gether  with  a single  specimen  of Peloscolex velu-
tinus) in much the same numbers, but not necessarily
in the same  places, as before.  The one clear cor-
relation was between  the occurrence of  Branchiura
sowerbyi  and a warm water effluent from a power
station (maximum temperature 25° C).
  Department of Zoology, University of Liverpool, Liverpool, England.

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58
ENVIRONMENTAL REQUIREMENTS OF FRESH-WATER INVERTEBRATES
   In contrast,  Ditton  Brook  is  a small  stream,
organically polluted by a piggery and then blanketed
with coal particles from the washing plant of a near-
by mine.  The relative abundance of Tubifex tubifex
and Limnodrilus species in the tubificid fauna varies
quite markedly  at different places and also  at the
same place over a period of time  (Tables 2 and 3).
This  sort of  observation was made by Dr. Purdy,
a  former worker  in this institution (S.E.C.), but I
have not included  his work  in this  review as I have
yet to see his unpublished data which  might modify
or  extend what little published information he left
us.

   It is not, therefore, easy to decide which factors
of the environment are important and require detailed
                                    periment until  the  field  observations  are  better
                                    developed.

                                    a. Substratum

                                       Valle  (1927),  Rzoska (1936), Szczepanski (1953),
                                    Brinkhurst  and  Kennedy  (1962), and probably  other
                                    authors  have noted  apparent  correlations between
                                    the nature of sediments in lakes and rivers and the
                                    species of worms present (or the relative abundance
                                    of those  species), but these may  only  be used as
                                    pointers to further research in the  absence of care-
                                    ful studies  of replicate samples from each sediment
                                     considered.   Delia Croce (1955) studied the bottom
                                    sediments of Lake Maggiore in some detail, and from
                                    July  1953 to May 1954 samples were obtained from
                                    five depths in the lake. These were analyzed to pro-
             Table 1. TUBIFICIDAE COLLECTED FROM TRANSECTS ACROSS RIVER THAMES
            	AT READING, BERKSHIRE (April 14 to 16, 1959)	
Tran-
sect
1
2
3
5
Yards from
south or
north bank
S 1
5
10
20
40
55
S 1
2
5
Middle
N 5
3
1
S 1
S 4
N 1
S 1
3
5
8
20
N 1
Substratum
Gravel
Stones
11
ft
it
Black mud and
twigs
Mud
ti
Black, soft
mud
Shell gravel
Black mud
Over stiff
Clay
Mud
Black mud
(as N Tr. 2)
Oily black mud
n tt tt
tr tt tt
ff ft ft
Stones
(as N 2)
Vegetation
-
Acorus
it
Nuphar
Acorus, Glycerin
edge of Acorus
Carex, Acorus
Nuphar
tr
rt
Depth
in feet
1
2
7
12
12.5
4
1.5
2
3
10.5
4
2
1
2
2.5
6
1
2
4
6
8
4
Total (C 25)
Percentage composition
in 1962 (C. Kennedy)
SPECIES*
1
1
3
21
2
C
2
2
2
1
1
2
5
5
7
79
12.9
21.8
2
10
6
C
C
8
20
2
C
2
1
6
C
C
C
C
C
1
12
248
40.6
34.5
3
1

-
2
1



-
4
4
1
13
2.1
2.6
4
-

-
-



-
4
1
-
5
0.8
0.2
5
6
3
10

-
C
1
8
2
6



C

5
2
C
5
123
20.1
28.7
6
-



-
1



-

-

-
1
0.2
0.6
7
1

2
-
1
1
2
1



1

-

-
9
1.5
0.4
8
3

C
C
C
2
2
6



2

-

4
2
96
15.7
5.0
9
-

-
1



-

-

-
1
0.2
0.2
10
-

-
1



-

-

1
2
0.3
0.2
11
-

-
-



-
C
2

1
28
4.6
2.2
12
-

-
1

2
-
2
1
6
1.0
3.0
al. Limnodrilus claparedeanus + L. longus. 7. T. tubifex.
2. L. hoffmeisteri. 8. Psammoryctes barbata.
3. Euilyodrilus hammoniensis. 9. Psammoryctes albicola.
4. Euilyodrilus bavaricus. 10. Rhyacodrilus coccineus.
5. Euilyodrilus moldaviensis. 11. Branchuira sowerbyi.
6. Tubifex ignota. 12. Limnodrilus udekemianus.
 study.  Furthermore, the tolerance levels for cocoons,
 young worms, mature worms, and breeding individuals
 may  differ,  tolerance  limits may vary seasonally,
 and interactions between environmental factors will
 undoubtedly occur; and so, in practice, we may pre-
 fer  to  delay  the  establishment  of  criteria by ex-
                                     vide data on the numbers of the two species present
                                     in relation to the nature of the sediments, expressed
                                     as  the percentage composition by weight of  sediment
                                     in  each  of five fractions separated by  elutriation.
                                     The results were formulated as a general  rule: "The
                                     number of the Oligochaeta decreases when the per cent

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                                       The Biology of the Tubificidae
                                               59
 value of the II fraction increases, an opposite effect
 being displayed by the fraction IV, while fraction HI
 does not seem to have a definite effect." In practice,
 this rule holds good for one species (Peloscolexferox)
 at two of the depths studied, whilst the reverse is true
 at one depth for Bythonomous lemani.  There was no
 correlation at other  depths.  Therefore  it seemed
 difficult to  accept this as a general rule, especially
 as the analysis  was based on single samples, giving
 us  no idea  of the variation due  to sampling. With
 the assistance of Dr.  P.  M. Sheppard (Genetics De-
 partment, Liverpool) these results were reanalyzed.
 mean  sediment values changed steadily with depth,
 with an  abrupt change at the lowest level (30 meters
 = 2.84;  60 meters  = 2.83; 100 meters  = 2.82; 200
 meters  = 2.80; 300  meters = 2.67). In those three
 stations  with  a  positive correlation between particle
 value  and abundance of  P.ferox,  there  is clearly
 an increase in the population with time.   There are
 three  possible  interpretations  of  such a situation,
 all being  more  or   less  reasonable  in  biological
 terms.   Either the  particle  size  is  affecting the
 number  of worms or vice  versa, or some external
 factor (for which  we can use time) is affecting both
       Table 2. ANALYSES OF THE BOTTOM FAUNA PRESENT IN SAMPLES FROM DITTON BROOKa




Total number of
Tubificidae/100 cm3
% Tubifex tubifex
Total number of
cocoons/100 cm^
Total number of
Chironomus sp.
larvae/100 cmr

Transect 1
A
1

121
64.3

60


0
2

174
67.2

50


0
B
1

128
77.6

27


4
2

118
52.7

25


3
C
1

73
51.1

30


0
2

15
30.4

5


0

Transect 2
A
1

17
14.3

4


0
2

13
20.8

4


0
B
1

40
90.1

14


8
2

97
82.6

64


5
C
1

130
85.3

43


0
2

102
66.8

48


0
Transect
3
A
1

0
0

2


32
2

0
0

1


32
Transect
4
A
1

1
0

11


6
2

0
0

15


2
 aNumbers given per 100 cm3 of mud.  Four transects were sampled at left bank (A), midstream (B), and
  right bank (C).Duplicate samples were outained at each station (Al, A2, Bl, B2, etc.).  Remaining tubificid
  fauna chiefly Limnodrilus hoffmeisteri and some L. udekemianus.
                    Table 3. PERCENTAGE OF TUBIFEX TUBIFEX IN SAMPLES FROM
                               STATION 3A IN DITTON BROOK, 1959-60a
Month
% Tubifex
tubifex
1
28

3
42

5
47

6
58

7
33

8
43

10
40

11
33

12
33

  *Based on subsamples from qualitative samples only.
We first obtained a single measure of the nature of
the sediment in each  sample by  deriving  a mean
fraction value  from  the  percentage  composi-
tion  by   weight  of each   fraction  (obtained as
%IxI -%IIx2 ...%Vx5).   It was then found that
            100
there was  a positive significant correlation between
the mean  sediment value  and the abundance of P.
ferox at three  depths  in Lake Maggiore (60 meters,
r  = 0.844 P <0.01;  100 meters, r = 0.82 P <0.01;
300 meters, r  = 0.647 P <0.05) but a  non-signifi-
cant  negative correlation  at  the  other two depths.
Furthermore, there was a steady shift in the mean
sediment  value  with time  (from  about 2.3 to 3.1)
which occurred at all depths.   The mean of these
independently.  Using partial correlation analysis on
the data  obtained  at 60  meters  (where the cor-
relation between particle value and worms is stringent
when  time is ignored), we find that when the correla-
tion due to time is  removed, the correlation between
sediments and P.  ferox abundance is insignificant
(r 12.3 =  0.151 with 6 degrees of freedom).  There-
fore,  it would appear that some external agency was
increasing the mean particle value and the numbers
of P. ferox  at  the same  time. We may therefore
suppose the  particles were becoming  lighter with
time as particle fraction I  consisted of the heaviest
particles.  There is also what would appear to be a
highly significant correlation between the percentage
of P, ferox  as opposed to  B. lemani and depth, with

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 60
ENVIRONMENTAL REQUIREMENTS OF FRESH-WATER INVERTEBRATES
a  critical  depth between 100 and 200  M.  The per-
centage of P. ferox is  given  as  follows: 30 meters,
74.02 to 75.00; 60 meters, 75.75 to 71.60; 100 meters,
76.44 to 71.65; 200 meters, 45.00to 48.57; 300 meters,
43.51 to  51.48 percent, indicating another factor im-
portant in  determining  the relative  abundance of the
worms, such  as the distribution limits of a predator
or the physical-chemical conditions  in relation to the
thermocline  or  the  like.  If the results  of such de-
tailed work (albeit omitting duplicate sampling) can-
not establish a direct relationship between worms and
sediments, we may view more superficial correlations
based on visual estimates with suspicion.

   Two species which might well  repay detailed study
in relation to sediments are Rhyacodrilus coccineus,
which  is found widely in sandy  rivers and  streams
but very seldom in soft mud, a.ndAulodriluspluriseta,
which is usually found  in association with  very fine
silt.  I intend to investigate  this problem  by taking
a large number of samples at one time from a con-
stant depth in a lake as soon as possible.

b. Organic matter in sediments

   Ravera  (1951) studied the populations of benthonic
animals  in a newly cut-off  meander  of the River
Toce,  where  the most  abundant  animals were tubi-
ficids (probably Psammoryctes barbata). This showed
that "The  Tubificidae  population density increased
from the upstream to  the downstream  zone of the
meander, and everywhere  from  the beginning to the
end  of the research period; in the same way the per-
centage organic matter varied within the sediments."
Again we have a correlation, but possibly not proof,
of a causative relationship between percentage organic
matter and tubifieidae  alone.   Delia  Croce (1955)
found  no  such   correlation   between  total organic
matter and worm abundance in Lake Maggiore.  The
significant factor here  may  be  that fraction of the
organic matter supporting bacterial colonies.

c. Chemical factors

   In my paper  read at Madison Wis. (Brinkhurst,
1963) I have listed those  species that appear to be
marine, those which are restricted to brackish water
or water of varying salinity in estuaries, and those
predominantly freshwater  species than can withstand
some degree  of salinity.  It is,  therefore, apparent
that chloride ion tolerance  (probably  together with
competition from other  species) may limit  the dis-
tribution of some species.  In a fast-running stony
stream in England  with a salinity of 150-250 ppm
Cl  (maximum  505 ppm) associated  with  a BOD
averaging about 35 ppm (maximum  55.4 ppm) and a
percentage saturation with oxygen varying from 10.7
to  88.9  percent,  a dense tubificid population was
made up largely of  Psammoryctes barbata  together
with  Tubifex  tubifex, Limnodrilus hoffmeisteri, and
Limnodrilus udekemianus.   Rhyacodrilus coccineus,
which  was common in  the main river of which this
was a tributary,  was  absent here; the absence is
probably associated with  the periodic shortage of
oxygen rather than the high  salinity figure.  Psam-
moryctes barbata  has also been recorded more often
from rivers  in which  we suspect a relatively high
                                    calcium  content, but it is clearly  not  restricted by
                                    relatively high chloride levels in fresh water.

                                       Jones (1938)  reviewed the effects of heavy metals
                                    on freshwater  animals.   These showed that water
                                    from  copper stills was  lethal to "Tubifex" but  that
                                    this  effect  could  be dispelled  by using amorphous
                                    substances  of various  kinds.  Potassium chloride
                                    rendered "Tubifex"  inert, but it recovered upon ad-
                                    dition  of  calcium chloride.   Lead nitrate at a con-
                                    centration  of  0.01 N was lethal to "Tubifex" in 30
                                    minutes, 0.08 N  in  60  minutes, but the addition of
                                    lead nitrate to  copper nitrate at  0.05 N  showed an
                                    increased survival up to 0.01 N lead nitrate, but an
                                    enhanced  toxicity at higher  concentrations  of lead
                                    in the copper solution.   These facts are indicative
                                    of the complexity of the possible interactions between
                                    factors of the environment.

                                       Hynes  (1961) has  shown that various oligochaetes
                                    Nais pseudobtusa  (determination  regarded  as  un-
                                    certain),  T. tubifex,  Lumbriculus  variegatus, Eise-
                                    niella  tetraedra) became abundant  in a  small  stream
                                    subsequent to pollution from sheep dip  containing the
                                    insecticide BHC, and suggested that this was  due not
                                    only to an ability to survive the insecticide but also
                                    to the absence of predators.

                                    d. Oxygen

                                       There  is little information regarding the  oxygen
                                    requirements of various  tubificids. It  is well known
                                    that  Jiese worms contain red blood pigments and that
                                    some,  at least,  can survive when oxygen tensions
                                    are very low indeed for considerable periods.  Alster-
                                    berg  (1922),  Dawsend  (1931) and Harnisch (1935)
                                    investigated  the physiology  of respiration,  chiefly
                                    with T.  tubifex if we are to believe the identifica-
                                    tions.    Eggleton  (1931)  expressed the  view  that
                                    tubificids were  facultative   rather than  obligatory
                                    anaerobes,  as  have  many other workers.  Fox and
                                    Taylor  (1955) showed that pure oxygen was lethal to
                                    tubificids,  but  that  newly hatched worms survived
                                    best at low oxygen tensions and grew three times as
                                    fast  as when kept in well aerated water. Berg et al.
                                    (1962)  have established  that T. tubifex  and Lim-
                                    nodrilus udekemianus  take  up oxygen at a fairly
                                    steady rate down  to  4 percent oxygen (as percentage
                                    of a  gas  mixture  in  equilibrium with the  water)
                                    whereupon the rate  falls rapidly to a  critical value
                                    at about 2.5 percent.   Rather  comparable  results
                                    were obtained  with two other species, Euilyodrilus
                                    hammoniensis and Psammoryctes barbata.  As we
                                    would  expect, then, some species  at least can take
                                    up oxygen at very low concentrations.

                                       Differential   survival  of   species in  relation to
                                    oxygen concentrations is probably implicit in much
                                    of what follows  in section 3, but we have insufficient
                                    data available in the way of  continuous  records from
                                    single  localities  to define  tolerance  limits here.

                                    e. Temperature

                                       Berg  et  al.  (1962) have  shown that temperature
                                    affects  the  respiration rate of tubificids, and Daw-
                                    send (1931) has shown that they withstood anaerobic

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                                      The Biology of the Tubificidae
                                                61
conditions  for 48 days at 0° to 2°C  but only 9 days
at 18° to 20° C.  Mann (1958) and Brinkhurst (1960)
have recorded the distribution oiBrcmchiura sowerbyi
in  relation  to  a warm  effluent in  the  Thames at
Reading, which  reaches a maximum  of 25° C. This
is a  tropical species  that  occurs  in many  botanic
gardens  and that has escaped to the  wild in Europe,
not  only  to warm  sites  but also to  quite normal
temperate  habitats.   Beyond  this, however,  I  can
find no references to the  effects of temperature on
tubificids.

   In general, this  approach  to the subject under
consideration is fraught with difficulties, particularly
as  laboratory  studies  of  individual  components of
the environment will tell us little about the distribu-
tion and abundance  of  the worms in  nature.  These
studies usually  ignore  interactions  of various com-
ponents of the environment and the differences between
eggs, young  and old  individuals, as well as seasonal
fluctuations in the animals' requirements.  Over  and
above  all this, biotic factors are apparently ignored
altogether.   It would seem best to study the animals
in the field until we know what questions to investi-
gate in the laboratory, rather than blindly accumu-
lating  physiological data which may  or may not prove
to be ecologically significant.
2. Indicator species.

   I  am prepared to state quite categorically that
there is no such thing as a universal indicator species
of worm,  the presence  or absence of which will
indicate the degree of pollution by all or any effluent.
I venture  to  suggest that this  is true for other taxo-
nomic groups, even more  so  of  entire families,  as
insects.   The foundation for  the  search for  such
species, usually  in  relation to organic pollution, ap-
pears to be that the more widely distributed and catho-
lic in its  requirements a species is, the more likely
it will  survive in  extreme habitats, free from the
competition of more specialized and possibly, there-
by, more efficient related  organisms.  I have been
struck by  this point in  considering the biology of
several very  common species,  not least  of which
are  Tubifex  tubifex  and Limnodrilus  hoffmeisteri.

   May  I note  at  this point that in such abundant and
apparently cosmopolitan species there may lie hidden
taxonomic  criteria that will eventually separate enti-
ties  presently  considered part of a single species;
but for  the present let us  accept the taxonomy as it
now stands.
   These  two  tubificids  are  the  first found in any
random collection of worms from most parts of the
                          PERCENTAGE SATURATION OF DISSOLVED OXYGEN
                          NUMBER OF TUBIFICIDS COLLECTED
                          PERCENTAGE OF TUBIFICIDS IN TOTAL CATCH
               JUNE JULY AUG SEP  OCT NOV DEC JAN FEB MAR APR MAY JUNE JULY AUG  SEP OCT NOV DEC JAN FEB
               1926                         1927                                            1928
     Figure 1.  Correlation between the percentage of tubificids in the fauna and the percentage saturation of oxygen in the River Lark.

-------
62
ENVIRONMENTAL REQUIREMENTS OF FRESH-WATER INVERTEBRATES
world.  They are  found in all  sorts of habitat, often
together with many other species. They are, there-
fore,  valueless  as indicators  in the narrow sense.
Nonetheless, it is these  two species  par excellence
that reach such astronomic numbers in the absence
of predators and competing species,  such as erpob-
dellid leeches and  some fishes, whenorganicpollution
reaches  such limits as to render the water and the
mud anaerobic for prolonged  periods.  These then
would  be our polysaprobic species.   They  are un-
fortunately  not  restricted  to  polluted water,  and,
furthermore, they  are killed  by  small amounts of
metallic poisons.   They survive blanketing by in-
organic material as long as there is enough organic
material to provide  (directly  or indirectly) a food
supply.

   It  is  impossible for an investigator unskilled in
biology to identify a  handful  of worms and report
on  the  status of  the  water  examined.  An analysis
of the total fauna (including fish if  sufficient time
and labor is available to collect a series of samples
despite shoaling in age classes and if sufficient note
is taken of  their extreme mobility in assessing the
                                    results of analyzing such samples), preferably the
                                    bottom fauna of a  series of  stations with as near
                                    uniform a substratum as possible, may be of great
                                    diagnostic value if as many  species  as possible are
                                    identified.  I will now outline the  sort  of pattern
                                    that may  emerge  in relation to worms when we have
                                    surveyed  enough waters in which the sites and nature
                                    of effluents are known.
                                    3. Analyses of worm populations in polluted rivers.
                                       There  are of course many examples of the abund-
                                    ance of tubificids below sources of organic pollution.
                                    I shall take the study of  the River Lark (Butcher et
                                    al.,  1930) as  my example, as  this is about the first
                                    of such studies  of  a British river.  Figure 1 shows
                                    the correlation between the percentage of tubificids
                                    in the  fauna  and the percentage saturation of oxygen.
                                    The number  of tubificids  actually  fell  when the
                                    oxygen level was at a  minimum, however.  The in-
                                    crease in number of worms after  the pollution was
                                    attributed  not only to  favorable  conditions and an
                                    abundance of food, but also to the absence of predators
                                    and  competitors i.e. the worms  may  survive the
                                    pollution rather than be favored by it.
            Table 4. TUBIFICIDAE FOUND IN VARIOUS RIVERS IN RELATION TO THE DEGREE
                                 OF ORGANIC POLLUTION OBSERVED
 Status of pollution
                                              Speciesc

Gross a

Bad
Recovery or slight
b
b
Clean (Actual numbers given)
1
++
-t-
+::
+
+
+
i
2
++

£
+++
+++
++
4
3


:
+
-


4



;
*+


5


+
I
+

1
6




+


7




-

3
8




+

1
9



+

I
15
10



+
-


11



-



 aThere is a very large number of streams in this category in which species 1 and 2 are very abundant.

  There are several examples of these patterns.

 cl.  Tubifex tubifex,    2. L. hoffmeisteri,   3.  L. udekemianus,
  4.  E. hammoniensis,  5. P. barbata,       6.  T. ignota,          7. E. moldaviensis,
  8.  A. pluriseta,      9. R. coccineus,    10.  E. bavaricus,     11. P. velutinus.

-------
                                      The Biology of the Tubificidae
                                               63
   Table 4 gives enough of a rough indication of the
relative  abundance  of  tubificids in a series of or-
ganically  polluted  rivers  to give a general idea of
the sort of pattern which  may emerge from detailed
research,  although I  realize  a  certain  degree of
circular argument is  involved here.   Parallel in-
vestigations on the rest of the fauna and the chemical
conditions of these rivers were sometimes available
to support the bald assertion regarding the degree of
pollution, but the data available on the worms are not
sufficiently  detailed  to warrant their inclusion.  I
repeat that this is intended to give a superficial view
of what  we might expect from a future  research
program.

   In two surveys there is a little more information
available.   The  first  example (for which I am in-
debted to Dr.  Hynes)  shows how  oligochaetes may
become abundant below a source  of organic pollu-
tion.   The  figures  refer  mostly to  Tubifex tubifex
and  to  the  Lumbriculidae, Lumbriculus variegatus
and Stylodrilus keringianus (Table 5),  The  suspended
matter in the polluting material may  well make the
river  a more  suitable habitat for  Lumbriculidae
(which are sparce above the effluent), but the effects
of the local deoxygenation  seem to vary considerably
from year to year, possibly due to variation in the
degree  of pollution.   The point of entry of the pol-
luting material is obvious in both parts of the table,
and there may  be a correlation between the severity
of the pollution, the abundance  of the Tubificidae and
(negatively)  the  abundance  of the Lumbriculidae.

   The second example  concerns another large British
river which has been under investigation for  some
years and has included six surveys. The sites studied
were all  sand-gravel banks which usually support
few  species  of  tubificid  other than Rhyacodrilus
coccineus.   The results of the most  recent survey
(Table 6) are given in detail,  and  the effects of the
major  effluent may be  seen. The river is  now much
cleaner than in previous years (when the BOD reached
25 ppm in midsummer as opposed  to 4  to 6 ppm
 now),  and this is illustrated in Table 7 where the
 results of all  surveys are given for the four stations
 below the effluent.

   From  these and  other  surveys we may attempt
 the following tentative summary:

(1) Tubifex tubifex and Limnodrilus hoffmeisteri.

   These two   species  are  the most resistant to
 organic and  inert mineral pollution in Britain.  They
 occur together  in varying proportions in the absence
 of other species. They may reach astronomic numbers
 in the absence of predators,  especially  erpobdellid
 leeches.  When these leeches are present, the stand-
 ing  crop of  worms may be low but the productivity
 high.

 (2) Euilyodrilus hammoniensis, Psammoryctes bar-
   bata, and Limnodrilus udekemianus.

   These species  occur in organically polluted water
 where the number of worms is still high, but they are
 apparently a little less resistant than the above (vide
 Berg,  Jonasson, and Ockelmann, 1962).  P. barbata
 may be  very  common  in grossly polluted streams
 where the oxygen level  is still high owing to rapid,
 very turbulent flow.  (Only the third of these species
 has been found in the United States to date).

 (3) Rhyacodrilus coccineus appears to prefer  sandy
 gravel to mud,  seems to be able to withstand slight
 pollution, but is more sensitive than any of the above.

 (4) Many  other  species  seem to occur only in clean
   streams.

   The pattern seems to be similar on other conti-
 nents  from which  I have received samples, but some
 other  species may  enter the pattern such as Branch-
 iura sowerbyi  (Allanson,  1961;  Vaas  and Sachlan,
 1955).

   We have  even less information about other fami-
 lies  of Oligochaeta.  Nais elinguis (Naididae) has
 frequently been found in large numbers in organically
        Table 5. THE SMALL OLIGOCHAETA OF A POLLUTED RIVER (data from Dr. H.B.N. Hynes)a



Tubificidae
(mostly T. tubifex)





Lumbriculidae
(S. heringianus
L. variegatus)




Annual
survey
No.
1
2
3
4
5
6
7
1
2
3
4
5
6
7
Stations
123 4

1 14
2
44
148
22
1 127
1820


1
1 1
4
13

5

2

4
1



4

2

10
6

6


1

11

1

2
3
1


2

7

2

2




24

4


1

8






2

2


1

7

9




1



5
2

1
4
5

10 11 12

1

-
-
-
-
-
1 1
2 1
-
4-1
3
2
-
13

_
-
-




_
-
-
2



 aTributary introducing organic matter enters the river between stations 3 and 4.

-------
64
ENVIRONMENTAL REQUIREMENTS OF FRESH-WATER INVERTEBRATES
                    Table 6.  THE SMALL OLIGOCHAETES OF A POLLUTED RIVER
Species
Tubifex tubifex
T. tempeltoni
Limnodrilus hoffmeisteri
L. udekemianus
Euilyodrilus hammoniensis
E. moldaviensis
E. bavaricus
Rhyacodrilus coccineus
Aulodrilus pluriseta
Bothrioneurum vejdovskyanum
Psammoryctes barbata
Pelo scolex ferox
Nais elinguis
Ophidonais serpentina
Stylodrilus heringianus
Enchytraeidae indet.
Stationsa
1
5

14
c
c

c
7
1


c
4
1
8

2
1

2




4




8

28

3
c

1

c





1

b


47
4
1

21

c
1

2


c

12

1
6
5 6
c

c 15
1



8 8


1 6

3

6 1
35
7 8
c c
c
6 1
c
c


1 4


4

b

2

9
6

10

6


c




6


2
10
c

32

1




3
1

1


4
11
5

42
c
c


c


3





12
c

45
c
c


3


2





13
4

17
c
2



c
9
2





 al - above most pollution.
   2,3 - below organically polluted tributary.
   4 - below an effluent (BOD 50-100 ppm, flow 0.1 mgd).
   5,6 - above main sewer.
   7 - below main sewer (BOD 12, flow 12 mgd).
   8 - Intermittently stagnant cut.
   9-13 - mostly recovery, with small sewage works effluent.
                                      b - very abundant

                                      c - present in previous surveys
        Table 7. TUBIFICIDAE OBSERVED AT FOUR STATIONS BELOW THE MAIN SEWAGE WORKS
          EFFLUENT ON A POLLUTED RIVER (as in Table 6) OVER SIX SUCCESSIVE SURVEYS
Species
Tubifex tubifex
T. templetoni

Survey


Limnodrilus hoffmeisteri
L. udekemianus

Euilyodrilus hammoniensis
Bo thrioneurum vejdovskyanum
Rhyacodrilus coccineus
Psammoryctes barbata
Total numbers of all worms
in sample.

Station 7
123456
++ ++ ++ ++ 2 0
1
++ ++ ++ 16 6

+ 8

+ 11
4
A A A 16 A 40

Station 8
12356
++ ++ ++ 1 0

++ ++ +4- 3 1
+ 1
+ + 4

4

A A 1 16 5

Station 9
123456
++++++++ 9 6

++ ++ ++ ++ 5 10

+ + + 66

+

A A A 40 42 45

Station 10
123456
++ ++ 1 + 1 0

++ 4 + 5 32

6 + 1
3

1
A A 11 16 6 60

A-Very abundant, impossible to estimate by the technique used.
polluted  streams  (especially where Cladophora is
abundant) and Stylodrilus heringianus (Lumbriculidae)
seems to  tolerate a certain amount  of  pollution.

Conclusions.

1. We know very little about the biology of aquatic
   oligochaetes.
2. What  little we do know  indicates  that detailed
                                      quantitative  surveys  of  the  species  occurring
                                      below  known  sources of organic pollution will
                                      enable us to use tubificids, in particular, in the
                                      detection  and assessment  of  pollution in  other
                                      rivers.
                                   3. A marked absence of oligochaetes and other soft-
                                      bodied animals in apparently suitable habitats may
                                      be useful in the detection of effluents  containing
                                      poisonous metal ions.

-------
                                      The Biology of the Tubificidae
                                               65
                                             REFERENCES
Allanson, B.  R.  1961. The physical,  chemical  and
biological conditions in the Jukskei Crocodile river
system. Hydrobiologia  18: 1-76.

Alsterberg, G.  1922.   Die respiratorischen Mech-
anismen der  Tubificiden.  K. fysiogr. Sallsk. Lund.
Forh. 18: 1-176.

Berg,  K.,  Jonasson,  P. M. and  Ockelmann, K. W.
1962.   The respiration of some animals from the
profundal zone of  a lake.  Hydrobiologia 19: 1-39.

Brinkhurst, R. O. 1960.  Introductory studies on the
British Tubificidae (Oligochaeta).   Arch. Hydrobiol.
56: 395-412.

Brinkhurst, R. O.  1962.  Taxonomic studies on the
Tubificidae. Int. Rev. Hydrobiol. (in press).

Brinkhurst, R. O. 1963. Taxonomical studies on the
Tubificidae  (Annelida,  Oligochaeta), Internat.  Rev.
Hydrobiol. (Systematische Beihefte) 2: 1-89.


Brinkhurst, R. O.  and Kennedy, C. R. 1962.  Some
aquatic Oligochaeta from the Isle of Man with special
reference  to  the Silver Burn Estuary. Arch. Hydro-
taiol. 58: 367-?76.
Butcher,  R. W.,  Pentelow,  F.T.K.  and Woodley,
J.W.A.  1930.   An investigation of the River Lark
and the effect of beet sugar pollution. Fish. Invest.
Lond. S.I, 3.

Dawsend,  K. 1931.  Uber die Atmung der Tubificiden.
Z. vergl. Physiol.  14: 557-608.


Delia Croce, N. 1955.  The conditions of sedimenta-
tion and their relations with Oligochaeta populations
of Lake Maggiore.  Mem. 1st. Ital. Idrobiol. suppl.
8: 39-62.
Eggleton, F.  E.  1931.  A limnological study  of the
profundal bottom fauna of  certain fresh water lakes.
Ecol. Monogr. 1: 231-332.

Fox,  H.  Munroe, and  Taylor, A.E.R.  1955.   The
tolerance of oxygen  by aquatic invertebrates.  Proc.
Roy. Soc. B. 143: 214-225.

Harnisch,  O.   1935.    Versuch  einer  Analyse des
Sauerstoffverbrauchs von Tubifex tubifex. Z. vergl.
Physiol. 22: 450-465.

Hynes,  H.B.N. 1961.   The effect of sheep dip con-
taining the insecticide BHC on the fauna of a small
stream.    Ann.  trop.  Med.  Parasit.  55:  192-196.

Jones, J.R.E.  1938.   Antagonism between two heavy
metals in their toxic action  on freshwater animals.
Proc. Zool. Soc. Lond. (A). 108: 481-499.

Mann,  K.H. 1958.   Occurrence  of  an  exotic oligo-
chaete Branchiura sowerbyi  Beddard,  1892, in the
River Thames. Nature Lond. 182: 732.

Ravera,  O. 1951. Velocita di corrente e insediamente
bentonici  studio su una lance del Fiume Toce.  Mem.
1st. Ital. Idrobiol. 6: 221-267.

Rzoska,  J. 1936.  Uber  die Okologie der Bodenfauna
im  Seenlitoral.  Arch. Hydrob. Rybact. 10: 76-171.

Szczepanski,  A.  1953.   Analiza dynamiki populacji
skaposzczetow dna wisly pod Warszawa.   Polskie
Archivum Hydrobiologii 1: 227-250.

Vaas, K.F. and Sachlan.  1955. Cultivation of common
carp in  running  water  in West Java.   Proc. Indo.
Pacif. Fish Coun. 6: 187-196.

Valle, K. J. 1927. Okologische - limnologische Unter-
suchungen uber die Boden und Tiefenfauna in einigen
Seen  Nordlich vom  Ladoga-See.  Acta  zool.  fenn.
2: 1-179.
                                             DISCUSSION
   The  discussion  centered  around  the following
headings:   The Winogradsky column, Protozoa and
toxicity, pollution indicators,  and definitions of pol-
lution.   In  addition to  the chairman and speakers,
persons  taking part in the discussion included B. R.
Allanson, T. W. Beak, R.  J.  Benoit, W. D. Burbank,
P. Doudoroff, W.F. Hahnert, T. E. Maloney, W, Ohle,
R.  Patrick,  W.   E.  Royce,  R.  E. Warner,  C. G.
Wilber, and  C. B. Wurtz.

   The Winogradsky column compares favorably with
conditions along  the shore but not  at the bottom of
a pond.  The  photosynthetic bacteria in it use scav-
enger  light.   On the lower side of a lilly leaf they
use what light is left.  A fluorescent lamp will not
cause the bacteria to develop.

   Protozoa are  relatively insensitive to toxicants,
an  example being  nerve gases.  Protozoa are not
related to organs of higher  animals and man.  Sur-
prise was  expressed  that Protozoa are insensitive
to nerve gases  since Tetrahymena  is  sensitive to
them,  the  response   test  utilizing movement.  If
pure  cultures are used Tetrahymena  is  found to

-------
 66
ENVIRONMENTAL REQUIREMENTS OF FRESH-WATER INVERTEBRATES
be sensitive to botulinus toxin.  Ciliates are sensi-
tive  to colinesterase.   Critical tests  on many of
these have not yet been published.

   As to indicator organisms  for polluted water, the
reproducibility of samples is a problem. The number
of species of Protozoa that  might be identified is
endless, but of the common forms, there are about
55-60 species.  There appears to be no fixed com-
munity of Protozoa at the genus level. At the species
level,  there  is, for  the weed species.  It is inad-
visable to look at only one segment of the community.
Great consistency has been found  in  specific places
but chance may play an important role here.
   It  was suggested  that far too much reliance is
placed on the saprobic system. What is the mesosa-
probic  zone  in  terms  of  chemistry?  High or low
BOD or COD is  not satisfactory. Velocity variations
are important because the rate of flow causes changes
in the  fauna.   The  polluted  stream is  a complex
system; therefore, there are many  exceptions. Large
numbers of organisms occur at the point where pred-
ators are removed.  Some organisms are associated
with warm water discharge;  some are  much larger
                                     in  size  in  the warm water.  The amount of oxygen
                                     present  may or may not be an  important factor. A
                                     form such  as Tubifex tubifex  is one that  survives
                                     in the polluted area but requires a muddy substrate
                                     to  do so.   Possibly we need  to get away from the
                                     idea that correlations on a field basis can be devel-
                                     oped.   A fundamental basis is  needed for  correla-
                                     tions. We are forced into a corner at the moment as
                                     to interpretation of results.

                                        The meaning and value of  the  term pollution was
                                     discussed.   Pollution is essentially an increase in
                                     the amount of food available and  toxicity is a separate
                                     consideration; but there was objection  to  this as
                                     metals,  etc.,  are  needed.  Adjectives may  be  used,
                                     such as organic  pollution  and  toxic pollution.   If
                                     we define  pollution in terms of our own interests
                                     we get  many different  ones.   In a  sense, the term
                                     pollution is  out  of date because we lump so much
                                     under it.    It may be  useful  only for  lay groups.
                                     Several  terms have become meaningless except for
                                     laymen and non-technical persons, but since they do
                                     have this use, a word such as  "pollution" will have
                                     to be continued.

-------
            ENVIRONMENTAL REQUIREMENTS OF MARINE INVERTEBRATES
                                         M.R. Carriker,* Chairman
                          BIOASSAYS OF PULP MILL WASTES WITH OYSTERS

                                           Charles E.  Woelke t
                  INTRODUCTION

   Between 1924  and 1928 sulfite pulp mills began
discharging wastes into  the  waters of three of the
four principal oyster producing  areas of Washing-
ton  State.  Within a few years laboratory research
was begun to measure the effects of pulp mill wastes
on  oysters.   Research of  Hopkins,  Galtsoff, and
McMillin (1931) demonstrated the toxicity of calcium-
base sulfite waste  liquor (SWL)  to oysters  at con-
centrations between 500 and 10,000 ppm  (based on
10% total  solids).   Kincaid  and Benson observed
18.7 percent  mortality  of Olympia oysters  (Ostrea
lurida) in their controls  and  34.4 percent mortality
in 100 ppm after 132 days (Gunter and McKee, 1960).
Odlaug  (1949) found complete cessation of pumping
by  Olympia oysters after 15 days in 100  ppm of
fresh  calcium-base sulfite  waste  liquor.   Liquor
which  had  been  stabilized for several months had
less effect  on the oysters.  McKernan, Tartar, and
Tollefson (1949), in spite of high control mortalities,
concluded from their 575 day bioassay of calcium-
base sulfite waste liquor with Olympia oysters that:
"Statistical analysis of these results indicated  an
undeniable  correlation between the mortality of the
oysters and concentration of  SWL even at these low
concentrations;  concentrations at least as  low  as
13.0 ppm are inimical to continued Olympia oyster
culture."   The findings of these researchers  clearly
established the toxicity of sulfite waste liquor con-
centrations in excess of  100  ppm. In the mid 1950's
excessive mortalities (Woelke, 1956), reduced growth
(Woelke,  1958), poor condition (Westley, 1959b), and
reproductive anomalies (Westley, 1959a) of Olympia
oysters were recorded.

   Between 1956 and 1958 both the Washington De-
partment  of Fisheries and the Washington Pollution
Control Commission conducted extensive water samp-
ling programs in all oyster growing areas in Washing-
ton.  Sulfite  waste liquor concentrations based on
10 percent total solids, as measured by the  Pearl-
Benson (1940) test,  ranged from 0 to 143  ppm over
the oyster beds.  The Pearl-Benson indices varied
within areas,  between areas,  and seasonally.  Most
sample  values over oyster beds  were less than 20
ppm, and the trip averages were usually  less than
10 ppm (Westley,  1960; Wash. Poll. Control Comm.,
1957a, 1957b,  1958).

                     METHODS

   Since  the sulfite waste liquor  concentrations (as
measured by the Pearl-Benson test) in oyster growing
areas were  generally  less  than those studied by
earlier researchers,  a new bioassay program was
initiated in  1956.   In brief,  this involved: further
statistical  analysis of the results of McKernan et
al,  (1949);  placing floating  live  boxes at  various
distances  from  a  source  of pulp  mill  waste  to
bioassay  the  existing  field  conditions  relative  to
growth,  mortality,  and fatness of Olympia oysters;
a  3-year laboratory bioassay with Olympia  oysters
of the  concentrations of  sulfite  waste liquor  found
over  oyster  beds;  laboratory bioassays of low con-
centrations of sulfite  waste  liquor  with  larvae  of
Olympia and Pacific (Crassostrea gigas)  oysters;
bioassay of  sulfite waste  liquor  with Olympia and
Pacific oysters in a lagoon; and 48-hour bioassays
with fertilized Pacific  oyster  eggs exposed to water
from areas receiving pulp mill wastes. By following
this  approach, a bridge of biological  responses was
established from the original  oyster populations,  to
field  live boxes, to laboratory bioassays,  to lagoon
bioassays, and back to bioassays with oyster larval
development in water  samples from oystering areas
with and without pulp mills.

                     RESULTS

   Probit Analysis  of  McKernan et al.  (1949) Data

   Since high control mortalities (52% and 5 3%) raised
considerable doubts as to the validity  of the results
reported in 1949 by McKernan et  al., a more careful
statistical  analysis  was made of  their data by Junge
(1956).  Junge (op. cit., page 6) stated that:  "Standard
statistical procedures applied to these datapermitthe
calculation  of  mortalities  due to the sulfite waste
liquor alone for any concentration  within the effective
range.  Various mathematical considerations of the
data  indicate that  the  experimental work  was well
controlled  and that the calculated regression  line
given in Figure 1,  gives a very satisfactory repre-
sentation  of the results of the experiment.  The 95
percent confidence  interval on the expected mortali-
ties  is also plotted in Figure 1, and the  mortality
rates are calculated for the lower concentrations in
Table 2."

   In Junge's analysis he  used "Abbott's  formula"
to compute  an adjusted mortality which  could be
attributed  to  sulfite waste liquor alone.   He then
plotted the adjusted mortality against the logarithm
of concentration on probability  paper.  Using the
procedures outlined by Finney (1952), aprobit regres-
sion line was fitted to  the  data (Figure 1). He then
utilized the formula for the regression line to com-
pute the values in  Table 1.  From Junge's analysis,
* Chief, Shellfish Mortality Prog., U.S. Bur. Com. Fish., Biol. Lab., Oxford, Maryland.
+ Washington State Department of Fisheries, Shellfish Laboratory, Brinnon, Washington.
                                                    67

-------
68
                      ENVIRONMENTAL REQUIREMENTS OF MARINE INVERTEBRATES
I concluded that the concentrations of pulp mill waste
present in Washington waters could be having an effect
on the Olympia oyster mortalities.

FLOATING LIVE BOXES

   In December 1956,  floating live boxes  containing
2-, 3-, and 4-year-old Olympia oysters, were located
at various distances from the waste outfall of an
ammonia-base sulfite  pulp mill located at Shelton,
Washington.  Oysters collected from the same oyster
bed were cleaned of exterior  material and their size
determined by volume displacement before being put
into the live boxes. Mortality and size of the oysters
were determined at least once  a  month.  Water
samples collected adjacent to  the  live boxes were
analyzed for sulfite waste liquor and salinity. Fatness
of the 4-year-old oysters, as measured by the re-
lationship between  dried  meats and volume of  shell
cavity, was determined on February 1, 1958.

   Since the  pulp mill ceased operations in August
1957, the 13  months  of data summarized in Figure 2
reflect  oyster responses for 8 months during which
the pulp mill was in operation, followed by 5 months
during which the mill was  not operating.  Data from
the five live  boxes  located  0.75, 8,  10.5,  13, and
over 50 miles from the pulp mill showed no apparent
pattern of growth differences.  Condition factor was
poorest closest  to  the pulp mill,  with  no particular
pattern in locations farther from the mill.  Mortality
was  highest  closest  to the mill,  with  no particular
                 7.0-F
                 6.5--
                 6.0-.
                 5.5-.
              § 5.04-
              o:
              o.
                 4.5..
                 4.0--
                 3.5--
                 3.0 •-
                                98


                                95


                               •90

                                85
                                80

                              4-70 t
                                                                                      ,60
                            -I	1	^—^-
- -50

. .40

..30

  20
  15

 -10
                                  01
                                                                                          LJJ
                                                                                          Q_
                             2     3  4  5   7   10        20       40    60  80 100
                               CONCENTRATION OF SULFITE WASTE LIQUOR, ppm
                             200
                          Figure 1.  Junge's Probit analysis graph of McKernan, et al's 49A data.

             Table 1. CALCULATED MORTALITY AND 95 PERCENT CONFIDENCE INTERVAL
                       FOR LOW CONCENTRATIONS OF SULFITE WASTE LIQUOR
Concen.
S.W.L.
(ppm)
4
10
13
20
30

Calculated mortality
(percent)
11.7
33.6
41.9
56.3
69.0

95 percent confidence
interval
2.7 to 32.3
18 to 52.6
26.5 to 58.7
43.5 to 68.4
59.9 to 77.1

-------
                             Bioassays of Pulp Mill Wastes With Oysters
                                                                                         69
pattern farther  from the mill.  The Pearl-Benson
indices averaged over 7  ppm at the live box nearest
the mill,  and averages were less than  4 ppm at the
other boxes.  Since the Pearl-Benson test measures
color producing  materials other than sulfite waste
liquor (commonly referred to as "background"), it is
questionable whether  more than a trace of pulp mill
waste was present except at the live box closest to
the pulp mill.

   These  data suggest that the concentration of pulp
mill wastes at  the live  box closest to the mill ad-
versely affected  the  mortality  rate and fatness of
the Olympia oysters but  probably did not affect the
growth.

LONG-TERM BIOASSAY

   In December 1958,  a 3-year bioassay  of ammonia-
base sulfite waste liquor was begun.  The bioassay
was  designed to  measure the effects of 2, 4, 8, 16,
32, 64, and 128 ppm of sulfite waste liquor (based on
10 percent total solids)  on the mortality,  growth,
fatness, reproduction, feeding, and histology of Olym-
pia oysters.

   The bioassay was  started with an initial popula-
tion of 5,400 oysters; each concentration and the two
                                              controls included  200  one-year, 200 two-year, and
                                              200 three-year-old oysters.  The physical facilities,
                                              methods for  supplying a  continuous flow of the
                                              waste,  and other details of the study  have  been
                                              previously  reported (Woalke 1960a).

                                                 The  bioassay was terminated  in  January  1962,
                                              and the data are being analyzed at the present  time;
                                              however, during the course of the study, preliminary
                                              analysis of the mortality data was made. In Figure
                                              3,  mortality  data from the  1956 and 1957  year-
                                              classes of  Olympia oysters exposed to sulfite waste
                                              liquor for  575 days are analyzed in the same manner
                                              used by Junge (op. cit.) and  compared with Junge's
                                              analysis of the data of McKernan et al. The regres-
                                              sion  lines  from the 1956 and 1957 year-classes are
                                              nearly identical.   These  lines,  however,  are at a
                                              lower level  and have  less  slope than  that  of the
                                              data  of McKernan  et al.  These differences indicate
                                              a lower level  of toxicity in our long-range bioassay
                                              than  those reported  in 1949.   While the possible
                                              reasons for these differences are of concern, the main
                                              point of interest lies in the apparent confirmation of
                                              conclusions by McKernan et  al, that low concentra-
                                              tions of sulfite waste liquor have adverse effects upon
                                              survival of Olympia oysters.
 300i

 200

 100
   0

  15

  10

   5

   0
  50

  40

  30

  20

  10

   0
  10
 I        III
     I
                                  GROWTH IN PERCENT SIZE INCREASE
 I
1
111
                                  CONDITION FACTOR INDEX
1
          III
                                  MORTALITY IN PERCENT
                                                                         I
                                        AVERAGE AND RANGE OF PEARL-BENSON INDICES, ppm
                III
                                              I
                                                         I
                                                                      I
                    10       15       20       25      30       35       40
                                DISTANCE FROM PULP MILL DISCHARGE, nautical miles
                                                                         45
                                                                       50
                            Figure 2. Results from 5 stations of floating live box study.

-------
70
ENVIRONMENTAL REQUIREMENTS OF MARINE INVERTEBRATES
                7.0
                6.5
                6.0
                5.5"
              o 5.0
              o:
              o.
                4.5
               4.0
                3.5
                3.0
                      PROBIT REGRESSION FOR TOXICITY OF
                      SULFITE WASTE LIQUOR TO OLYMPIA OYSTERS
 49 A
 56 YC
 57 YC
98


95


90

85

80

70 t
                                                              60 £
                                                                 o
                                                              50 if

                                                              40 u
                                                                 OJ
                                                              30 °-
                                                              20

                                                              15

                                                              10


                                                               5

                                                               2
                           2        4       8      16       32         64     128 150

                            CONCENTRATION OF SULFITE WASTE LIQUOR, ppm


                           Figure 3. Probit regression for toxicity of SWL to Olympia oysters.
         Table 2. SUMMARY OF OSTREA LURIDA LARVAL PRODUCTION PER 600 OYSTERS BY
            CONCENTRATION OF SULFITE WASTE LIQUOR.* JUNE 8 THRU AUGUST 7,  1959


Tray


Header box
Control (01)
Control (02)
2 ppm
4 ppm
8 ppm
16 ppm
32 ppm
64 ppm
128 ppm
Larval counts

Total


20
7084
9069
5923
5793
5893
6117
901
173
12

Normal


20
7068
9055
5912
5732
5349
2112
25
13
12

Abnormal


0
16
14
11
61
544
4005
876
160
0


Percent
abnormal

0
0.22
0.15
0.19
1.05
9.24
65.46
97.22
92.48
0
Calculated larval production

Number
of tows

174
169
169
166
167
170
172
168
171
171

Larvae
in tows

1,313
442,750
566,813
370,188
362,063
368,313
382,313
56,313
10,813
750

Per
tow

8
2620
3354
2230
2168
2167
2223
389
63
4
Total
produced
(thousands]

65.2
21,844.9
29,151.2
19,242.4
18,816.4
18,791.3
19,180.6
2,895.6
546.3
37.9
Total
larvae
per
oyster

36,408
48,585
32,071
31,367
31,319
31,634
4,826
910
63
Norma]
larvae
per
oyster

36,328
48,512
32,010
31,038
28,429
10,927
134
58
63
Larval size

No.


19
367
361
360
376
364
345
23
13
12

Average
size

165.0
157.8
158.6
154.9
153.3
150.9
139.2
161.2
159.2
164.1
* In view of the small numbers of larvae produced from the header box, no correction has been made for
  "wild larvae" entering the sea water supply.

-------
                                Bioassays of Pulp Mill Wastes With Oysters
                                                                                  71
OLYMPIA OYSTER LARVAL BIOASSAYS

   In  view  of the anomalies observed in reproduction
of Olympia oysters in the field in 1953,  1954, 1955,
and 1956, particular attention was given to the possible
effects of sulfite waste liquor on the reproduction of
Olympia oysters  in the laboratory studies.  Woelke
(1960a)  has described  the effects  of  various  con-
centrations of sulfite waste liquor on the spawning,
swarming,  and setting of Olympia oysters.  Most of
these  data  were  collected in  conjunction  with the 3-
year  bioassay of sulfite  waste  liquor with Olympia
oysters.

   In Figure 4 the spawning and brood development of
Olympia  oysters are summarized.  While  spawning
                                   occurred at all concentrations bioassayed, embryonic
                                   development  from eggs to  shelled  larvae  did  not
                                   take place in  concentrations above  16 ppm.  At 16
                                   ppm only limited development occurred. The develop-
                                   ment  at  2, 4,  and 8 ppm was less than in controls.
                                   Larval production, as determined by sampling water
                                   discharge in the  3-year bioassay,  is summarized in
                                   Table 2.  Very few wild larvae entered the sea water
                                   system to  affect  the  numbers found in the sampling.
                                   In  the  two  controls sampled,  percent  "abnormal
                                   larvae", i.e., larvae that are not fully shelled (Figure
                                   5),  was lower.  Numbers of larvae and average size
                                   of larvae  in  the two  control samples were superior
                                   to those at (of) any of the concentrations bioassayed.
                                   At  8  ppm there was marked increase in abnormal
                    27

                    18

                    9 -
                    0
                    27 -

                    18

                    9
                     0
                    27

                    18

                     9
                     0
                    27

                    18
               t-     0
               5    27
               E    18
               OL
    128 ppm
                                   n     H
     64 ppm
                           n     n     n
     32 ppm
                                           n     n
     16 ppm
                                                  fl
      8 ppm
                     Oi-
                    27 p

                    18 -
                     91-
      4 ppm
                     0
                    27
                    18
                     9 -
                     0 -
                          2 ppm
 0  	
27  -  CONTROL (01)

18  -
 g  _  none
                     ol—
                         gravid
n
       5/8    5/15
                                          5/22    5/29     6/5

                                                  DATE
                                6/12    6/19    6/26    7/3

                                   H   SHELLED LARVAE

                                   [  1   NONSHELLED LARVAE
                                     Figure 4. Olympia oyster spawning bioassay.

-------
72
ENVIRONMENTAL REQUIREMENTS OF MARINE INVERTEBRATES
larvae, decrease  in  numbers of larvae,  and de-
crease in size of  larvae  collected.  At 16 ppm over
50  percent  of the larvae were abnormal,  numbers
of  normal larvae  were reduced by over  60 percent
and size  of the  larvae  produced was  reduced by
over  12  percent.   Above 16  ppm no normal larvae
were produced.

   Larvae  spawned  in  the controls  and in 2, 4, 8,
and 16 ppm of sulfite waste liquor were cultured
in  the laboratory.  Larvae from  all except 16 ppm
were  successfully reared to  juvenile oysters.  Re-
                                 beakers containing concentrations  of the waste to be
                                 bioassayed.  After 48 hours the cultures were sampled
                                 and the  percent of  abnormal  larvae  determined
                                 (Figure 2).

                                    The results  of these studies  are summarized in
                                 Figure 7. Concentrations between 1 and6ppm caused
                                 an increase  in the percent of abnormal larvae above
                                 the  level of  the  controls.  Between 6 and 12 ppm,
                                 over 20 percent of the larvae were abnormal; from
                                 12 to 18 ppm, nearly 60 percent were abnormal;
                                 and above these levels, over 90 per cent were abnormal.
                                Figure 5. Normal and abnormal Olympia oyster larvae.
peated  efforts to raise larvae  spawned in  16,  as
well as 32,  64, and 128 ppm, were not successful.

   Failure to rear  larvae spawned in 16 ppm led
to the  conclusion that an increase in percent ab-
normal larvae represents an adverse effect on oyster
reproduction.  It was further concluded that, under
the  conditions of these bioassays,  fresh ammonia-
base sulfite waste liquor will interrupt the life cycle
of the  Olympia oyster at 16 ppm. Concentrations of
2,  4,  and  8 ppm  affect  the  reproductive cycle;
however,  these effects were not necessarily adverse.
PACIFIC OYSTER LARVAL BIOASSAYS

   While  the  Pacific  oyster  is  the most  valuable
shellfish  resource  of Washington State, a very few
reports on its response to sulfite waste liquor  have
been published.   In  1958, laboratory  bioassays of
sulfite  waste liquor  with  48-hour  larval  develop-
ment of fertilized Pacific  oyster eggs were started.
The  results  of  these bioassays  were reported by
Woelke (1960b).  The report was based on the results
of 338 larval  cultures. In  these studies about 15,000
fertilized  Pacific oyster eggs were  added  to 1-liter
                                   Table  3  compares  development of eggs fertilized
                                 in sulfite waste liquor with eggs which were fertil-
                                 ized  before  introduction into  the  waste.  In  this
                                 experiment the percent  abnormal  larvae in 3 ppm
                                 was 20 percent more than the controls.

                                   From  these  experiments it was concluded that:
                                 fresh  sulfite waste  liquor affected 48-hour develop-
                                 ment of fertilized Pacific oyster eggs at concentra-
                                 tions  of  2  ppm  and  greater; above 18 ppm, fresh
                                 sulfite waste liquor caused nearly  100  percent of
                                 the  developing 48-hour larvae to be abnormal; in
                                 some experiments over 90 percent of the larvae were
                                 abnormal at 12 ppm.  Below 13 ppm, 48-hour Pacific
                                 oyster  larvae developing  from  eggs fertilized in
                                 sulfite waste  liquor  had  higher incidence  of  ab-
                                 normality  than those introduced into the waste  1
                                 hour after fertilization.

                                 LAGOON STUDIES

                                   In  1958,  1959, and 1960 experiments  measuring
                                 chemical changes   of  sulfite  waste liquor  in  sea
                                 water  were  conducted in a lagoon  near the Point

-------
                               Bioassays of Pulp Mill Wastes With Oysters
                                              73
                                Figure 6. Normal and abnormal Pacific oyster larvae.
      Table 3. PERCENTAGE OF ABNORMAL LARVAE FROM EGGS FERTILIZED IN SULFITE WASTE
                 LIQUOR AND FROM EMBRYOS 1 HOUR OLD WHEN EXPOSED TO WASTE
Fertilized in S.W.L.
Pearl-Benson
Index
0
1

3
6
13

30
Percent
abnormal
6.3
10.8

26.8
23.7
99.2

100.0
1-hour embryos
Pearl-Benson
Index
0

2
3
6

14
31
Percent
abnormal
4.3

6.2
4.3
4.7

99.4
100.0
Whitney, Washington, Shellfish Laboratory. A 2-1/2-
acre portion of the lagoon is diked, and ingress and
egress  of water is controlled through two 30-inch-
diameter pipes.   The  remainder  of the  lagoon  is
open to the adjacent bay, and daily water exchange
takes place.  The pipes of  the diked portion of the
lagoon were closed and  sulfite waste  liquor added
until the desired Pearl-Benson index was achieved.
   In one experiment 13 ppm was maintained for over
a  year.   Additional waste was added every 7 to 10
days to maintain this Pearl-Benson index.  Experi-
mental populations of both Pacific and Olympia oysters
were  placed on trays inside the dike, and controls
were placed in similar trays outside the dike.  Peri-
odic measurements of growth, mortality, and fatness
were made on the oysters.
   It is  recognized  and readily acknowledged  that
the  controls  utilized were not all that could be
desired,  and  steps  are now under way  to  bisect
the present experimental lagoon with a dike to pro-
vide satisfactory  controls.   Results from the bio-
assay with  the present lagoon indicate adverse  ef-
fects on Pacific oyster fatness  and Olympia  oyster
mortality at 13 ppm.

Bioassays with Water Samples from Oystering Areas

   In 1961  and  1962,  bioassays of water collected
in the field have been conducted in the laboratory with
48-hour  Pacific oyster larval development utilizing
the techniques described by Woelke (1961).  Surface-
water samples were collected by airplane, and ferti-
lized Pacific oyster  eggs were  added within 3 hours
of the time the samples were picked up in the field.

-------
74
ENVIRONMENTAL REQUIREMENTS OF MARINE INVERTEBRATES
                100
                 80
              ^ 60
              O

              CD
              Ul
              u
              Of.
                  40
                  20
                  6         12         18
                    SULFITE WASTE LIQUOR,
                                                                      24
30
                                                                                          36
                      Figure 7. 48-hour development of Pacific oyster larvae in sulfite waste liquor.
To date 10  bioassays  of over  180  water samples
with more than 500 larval cultures have been  con-
ducted. These bioassays included water from oyster-
ing areas with and wihout pulp mill wastes.
   Results of these bioassays are  shown as percent
abnormal larvae in Figure  8.   The data  indicate
little difference between laboratory  controls and field
water samples with a zero Pearl-Benson index. The
same is true of Pearl-Benson indices of 1 to 6 ppm.
Above  7 ppm the percent abnormals increase sub-
stantially,  and above 30 ppm nearly 100 percent of
the larvae are abnormal.
   From these data it is concluded that Pearl-Benson
indices above 7 ppm in the natural environment (in-
cluding "background") have an adverse effect on the
48-hour development of fertilized Pacific oyster eggs.
                                                     SUMMARY

                                    The  results  of the bioassays are  briefly sum-
                                 marized in Table 4.   The Pearl-Benson index at
                                 which  adverse  effects occur  is:   an average of 7
                                 ppm on Olympia oysters in floating live boxes; about
                                 16 ppm (15% above control mortalities) on Olympia
                                 oysters in  the  long term  laboratory bioassay;  be-
                                 tween 8 and 16  ppm on Olympia oyster reproduction
                                 in the laboratory;  3  ppm  on Pacific oyster  eggs
                                 fertilized in laboratory mixes of  sulfite waste liquor;
                                 13 ppm in lagoon bioassays on Olympia and Pacific
                                 oysters; 7 ppm (including "background") on fertilized
                                 Pacific oyster eggs in water  collected from oyster
                                 growing areas.

                                                    CONCLUSIONS

                                    Throughout these studies, which began in the field
                                 and were followed by laboratory, lagoon, and, finally,

-------
                                Bioassays of Pulp Mill Wastes With Oysters
                                                75
field  water sample bioassays,  the  major objective
was  to determine  whether  the  quantities of  sulfite
waste  liquor in oystering areas was detrimental to
oysters.   At  no point  has  it  been clearly demon-
strated that the amounts of sulfite waste liquor present
over  the  oyster beds  in Washington  waters  could
be the one and  only cause for the death or distress
of an oyster or  oyster population.  On the other
hand it is concluded that the amounts of sulfite waste
liquor present  in some of these waters  can  create
stresses which,  if  not immediately lethal, may be
expected  to have  a  long term adverse  effect on
oysters.

   In comparing the various oyster responses studied,
the reproductive stage of the life  cycle seems to be
the most sensitive to  pulp mill wastes. The toxicity
of low concentrations  of  sulfite  waste  liquor  to
oysters is clearly indicated. This is especially true
when the concentrations bioassayed are  considered
on the basis of 100 percent total solids, rather than
the  10 percent   normally used with sulfite waste
liquor.  When  the 100 percent  total solids yardstick
is used, 5 to 10 ppm is clearly lethal to adults with
no  safety factor applied,  and, on larvae, between 1
and 2 ppm is lethal.

   Additional research  is  needed  to  demonstrate
whether the  acute toxicities measured by embryonic
development at low  concentrations are reflected in
less  obvious chronic stresses in adults.   Future
bioassays with water samples from oystering areas
shall be  conducted in which eggs  are fertilized in
the  samples.   Further  lagoon bioassays  shall  be
conducted after a satisfactory facility has been con-
structed.
                 100
                 80
                 60
              ce
              o
              CO
              u
              UJ
              °-  40
                  20
                      LAB. FIELD
                                                                     NO
                                                                    DATA
                                               6         12        18
                                          PEARL-BENSON INDICES, ppm
                  24
30
                                                                                           36
                           Figure 8. 48-hour development of Pacific oyster larvae in field water.

-------
76
ENVIRONMENTAL REQUIREMENTS OF MARINE INVERTEBRATES
               Table 4.  SUMMARY OF RESULTS OF BIOASSAYS OF SULFITE WASTE LIQUOR
                                WITH OLYMPIA AND PACIFIC OYSTERS
             Type of bioassay
                         Type of response
                         measured
                     P.B.I.* at which
                     adverse effects
                     occurred
             Floating live boxes
             (Olympias)

             Long range laboratory
             bioassay (Olympias)

             Olympia oysters in
             laboratory

             Development of Pacific
             oyster eggs fertilized
             in sulfite waste liquor

             Lagoon bioassays with
             Olympia and Pacific
             oysters

             Fertilized Pacific
             oyster egg development
             in field water
                         Mortality and
                         condition index

                         Mortality
                         Reproduction
                         Percent abnormal
                         larvae
                         Growth and
                         mortality
                         Percent abnormal
                         larvae
                     Average of
                     7 ppm.

                     About 16 ppm.
                     Between 8 and
                     16 ppm.

                     3 ppm.
                     13 ppm.
                     7 ppm.
 * Pearl-Benson Index
                                             REFERENCES
Finney, D.  J.  1952.
Univ. Press: 1-99.
 Probit  analysis.  Cambridge
Gunter,  Gordon  G.  and Jack McKee.  1960.   On
oysters and sulfite waste liquor.  Washington Pollu-
tion Control Commission. 93 pp.

Hopkins, A.  E.,  P. S. Galtsoff and H. C. McMillin.
1931.   Effects  of pulp  mill pollution on  oysters.
Bull.  U. S. Bur. Fish. 47: 125-186.

Junge,  Charles  O.,  Jr. 1956.   An  application  of
probit analysis techniques to a study of  the  effects
of sulfite waste liquor on Olympia oysters.  Wash.
Dept. Fish, manuscript.  7 pages.


McKernan, D. L., V. Tartar and R. Tollefson. 1949.
An  investigation  of the decline of the native  oyster
industry of the State of Washington, with special ref-
erence  to  the  effects of sulfite  pulp mill  waste on
the  Olympia oyster  (Ostrea  lurida).   Wash. State
Dept. Fish. Biol. Bull. No. 49-A, pp. 117-165.


Odlaug,  T.  O.  1949.  Effects of  stabilized and un-
stabilized waste sulfite liquor on the Olympia oyster,
Ostrea  lurida.   Trans.  Amer. Microscopic Soc. 68
(2): 163-182.
Pearl, Irwin A.  and A. K. Benson .  1940. A nitro-
solignin  colorimetric  test for  sulfite  waste liquor
in sea water.  Paper  Trade Journal 111 (18): 35-36.
Pollution Control Commission, State of Washington.
1957a. A reinvestigation of pollution in Grays Harbor.
Tech. Bull. No. 21, 51 pp.

1957b.   Pollution  investigation  in northern Puget
Sound. Tech. Bull. No. 22, 27 pp.

1958.  Water  quality data  Chehalis River - Grays
Harbor area, March-September 1958.  Water Quality
Data Bull. No. 58-1, 17 pp.

Westley, Ronald E. 1959a. Olympia oyster reproduc-
tion in south Puget Sound 1942-1958. Olympia Oyster
Problems,  Bull.  (5) 1-12.   Dept. of Fish.,  State
of Wash.

Westley,  Ronald  E.  1959b.   Olympia and Pacific
oyster condition  factor  data, State of Washington
1954-1958.  Dept. Fish., Shellfish Res. Lab.,  8 pp.

Westley,  Ronald E.  1960.   A summary  of recent
research by the Washington Department of Fisheries
on the distribution and determination of sulfite waste
liquor (S.W.L.).   Wash.  Dept.   of Fish. Research
Bull. No. 6, 7-43.

Woelke,  Charles  E.  1956.    Adult Olympia oyster
mortalities  1929-1956.   Olympia Oyster Problems.
Bull. No. 2, Dept. Fish., State of Wash.

Woelke, Charles E. 1958. Growth of Olympia oysters.
Olympia  Oyster Problems.   Bull. No. 6, 13  pp.
Dept. of Fish., State of Wash.

-------
                    The Effect of Environmental Factors on Larval Development of Crabs
                                               77
Woelke,  Charles E.  1960a.  Preliminary report of
laboratory studies on the relationship between fresh
sulfite waste  liquor  and the  reproductive cycle of
the  Olympia  oyster, Ostrea lurida.   Wash. Dept.
of Fish., Res. Bull. No. 6, 107-148.

Woelke,  Charles E. 1960b.   Effects of sulfite waste
liquor on the  normal development of Pacific oyster
(Crassostrea  gigas) larvae.  Wash. Dept.  of Fish.,
Res. Bull. No. 6, 149-161.

Woelke,  Charles E. 1961.  Bioassay  —  the bivalve
larvae tool.  Proceedings of the tenth Pacific North-
west symposium on water pollution research.  U. S.
Dept. of Health, Education and Welfare, Public Health
Service,  113-123.
         THE EFFECT OF ENVIRONMENTAL FACTORS ON LARVAL DEVELOPMENT OF CRABS*

                                   John D. Costlow, Jr.t and C. G. BookhoutI
   Larvae of the Brachyura, or true crabs, are found
 in virtually  all estuaries  and marine environments.
 In  some  areas they comprise an important portion
 of the zooplankton and represent such commercially
 important species  as  the  blue  crab, Callinectes
 sapidus Rathbun,  and the  stone  crab, Menippe mer-
 cenaria (Say).  Development of the Brachyura generally
 follows a certain pattern;  a series of free-swimming
 stages of the larva, which through successive molts
 attains an intermediate or transitional form, which
 in turn metamorphoses to the pre-adult. The majority
 of life histories that have been published have been
 based on reconstructions  from  larvae obtained from
 the plankton. The usual procedure has been to obtain
 the first-stage zoeae from a  crab that released the
 larvae in the laboratory, and then attempt to find the
 sequence of more  advanced  larvae in  the plankton,
 which appear to match the general characteristics of
 the hatched  first  stage. This procedure has resulted
 h descriptions of life histories that were not complete
 and  occasionally were based on larvae from several
 different species of  crabs rather than on one species.
 During the past few years techniques have  been de-
 veloped that allow the rearing of  crab larvae in the
 laboratory from eggs, through all larval stages, with
 a reasonabie degree of success (Costlow and Bookhout,
 1959,  19 JO,  1961).  In addition to providing positive
 identific; Jion of all larval stages of the species under
 study, tf ; laboratory  rearing also provides  large
 numbers  of larvae of known stage of development and
 age.  These can be used for studies on many ecological
 and physiological  aspects of larval development, which
 previously were impossible or impractical with larvae
 obtained from the plankton.

   Thus  far our  experiments have been primarily
 concerned with the  effects of three or four environ-
 mental factors on larval  development.  These have
included  studies  on  the individual  and  combined
effects of salinity, temperature,  diet, and light and
how these factors affect duration of individual larval
stages; the total time required for development of the
crab;  the  number of larval  stages; and the survival
of individual stages as well as the overall survival of
the  crab.   Of  the 20 species we have successfully
reared to date, 4 or 5  species will serve as examples
of how salinity and temperature can affect the various
phases of larval development of different species.

                      METHODS

   Ovigerous  females  of  Rhithropanopeus harrisi,
Panopeus  herbsti,  Sesarma  cinereum, Hepatus
epheliticus, and Callinectes sapidus were brought into
the  laboratory and maintained separately at 25 °C and
30°C in fingerbowls containing filtered sea-water of
the  salinity in which  the larvae were to  be reared.
With some species the  eggs were removed from the
pleopods of the female and hatched in plastic compart-
mented boxes maintained on an Eberbach variable-
speed shaker, as described by Costlow and Bookhout
(1960  a).   At the time of hatching  the zoeae were
transferred to  mass  cultures of approximately 500
per bowl  and recently  hatched Artemia nauplii and
fertilized  Arbacia  eggs  were added immediately.
The zoeae were then  further  subdivided into groups
of  10 per bowl and  maintained  under constant  en-
vironmental  conditions  in  temperature-controlled
culture cabinets. Artificial light for the 14-hour day
was provided by MacBeth Examolites, which  have a
spectral   distribution   similar to natural  daylight.
Larvae to be used in the experiments of 20 °C were
hatched at 25°C and  then  placed in sea water, the
temperature of which  was gradually reduced to 20°C.
A  minimum  of  100 larvae were used in  each tem-
perature-salinity combination given in Table 1.
 * These studies were supported by grants (G4400) from the National Science Foundation and from the Bureau of Commercial
  Fisheries.
 f Duke University Marine Laboratory, Beaufort, N.C.
 J Department of Zoology, Duke University, Durham, N.C.

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78
ENVIRONMENTAL REQUIREMENTS OF MARINE INVERTEBRATES
   The  containers and  larvae were examined daily,
the zoeae  changed to freshly-filtered sea water of
the same salinity, and  new food was  added.  At this
time the number of molts in each series was recorded
and the  mortality noted.  When the megalops stage
was  reached  the  larvae were  removed to separate
bowls  and individual records  kept on  the time of
metamorphosis to the crab.

         RATE OF LARVAL DEVELOPMENT

   The first crab to be considered isRhithropanopeus
harrisi, a Xanthid that successfully inhabits estuarine
waters of extremely low salinity.  For studies at our
laboratory it  has been collected from  the Newport
River  in salinities  of  0.5 to 25 parts per thousand
(ppt). Wurtz and Roback (1955) reported it from rivers
emptying into the  Gulf of Mexico in salinities that
ranged from 0.006 to 22.6 ppt and Ryan (1956) found
the adults  in portions of the  Chesapeake  Bay which
ranged in salinity from 2.8 to 18.6 ppt. Bousfield (1955)
is the only investigator who gives the range of salinity
in which the  larvae of this species may be found.
He collected  zoeae from  the Miramichi  Estuary in
Canada in salinities of 4.0 to 23.5 ppt.  and  found them
to be most abundant of 15.0 ppt.

   Unlike the  famales of some  species, ovigerous R.
harrisi  females  remain  in waters  of low salinity.
The eggs  and larvae of  this  brackish-water crab
have  been hatched  and reared in the salinity-tem-
perature combinations shown in Table 1.  The rate of
development of  larvae  of this species at comparable
temperatures  is not altered appreciably over the range
of salinities used.  More recently we have also reared
larvae  of  this  species  in 35  and 40 ppt and, while
development of  the crab was observed, preliminary
analysis of the data indicated that at 40 ppt there
was some slight delay  in development.  The absence
of any appreciable influence of a considerable range
of  salinities  on rates  of development of all larval
stages  of  R.  harrisi   is  in marked  contrast to the
effect  of salinity on rate of development of  larvae
of  other species  that have been  reared at our lab-
oratory.

   The larvae of a second species of Xanthid crab,
Panapeus  herbsti,  have  also  been reared under
different salinity-temperature combinations and are
more  sensitive to these environmental factors than
the larvae of R.  harrisi. We have collected ovigerous
females in the  Beaufort area in  water of a salinity
as high as 33.0 ppt, but the lower  limit of  the  salinity
range  for the  adults  is  not  known.   Ryan (1956),
studying the  distribution  of five  species  of  Xanthid
crabs  in the  Chesapeake Bay,  found a small number
of  adult  P.  herbsti  in waters  ranging  in  salinity
from 13.9 to 19.0 ppt. The present studies  have shown
that hatching of P. herbsti is successful in a salinity
range of from 12.5 to  31.1 ppt.  The duration of the
individual zoeal stages of this species,  as  well as
the  time required for complete  development to  the
first crab, are affected by salinity differences (Fig. 1).
A delay in the time of molting is  evident as early
as the  first  molt for  larvae  maintained in water
at a salinity of 12.5 ppt. The duration of the individual
 stages  of P. herbsti  was affected by temperature
                                   but  there was  some overlapping of the rates of de-
                                   velopment of the  earlier stages of 25°C.  Complete
                                   development of the larvae  at  30 °C required 18 to 28
                                   days.   This is  approximately half the time observed
                                   for  comparable development  of  these  same larval
                                   stages at 20°C (48 to 52 days).

                                      The larvae  of a third species of crab, Sesarma
                                   cinereum,  show  even  greater effects of salinity  on
                                   rate of development than the  two species previously
                                   considered.  The adult crab, a small dorso-ventrally
                                   depressed  crab,  which  lives  under  the moist  drift
                                   line  along protected beaches, is  found throughout
                                   much of  the estuarine area adjacent to the Beaufort
                                   Laboratory.  Pearse  (1936),  during  the summer of
                                   1928, found adult  crabs adjacent to waters that varied
                                   in salinity from  0.5 to 18.9 ppt.  Crabs used in our
                                   experiments  were  collected from areas  where the
                                   salinity  was 26.5 to  35  ppt.  While  hatching did
                                   occur in all salinities used in this experiment (Table
                                    1),  the duration of the individual stages and the time
                                   required for complete development to the first crab
                                   were affected by  the salinities used (Figure 2).  In
                                   the  lower salinities, 12.5 and  20.1 ppt, there was a
                                   tendency for molting of the individual stages to begin
                                   later than  at the higher salinities. This is naturally
                                   reflected in the time required for complete develop-
                                   ment (Figure 2).  At comparable temperatures there

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                                                       TEMPERATURE,°C


                                    Figure!. Comparison  of minimum and  maximum  time  of zoeal
                                            development (white),  megalops development (stippled),
                                            and  total development (black) to first crab stage for
                                            larvae of P. herbsti  reared under different salinities
                                            and  temperatures.

-------
                    The Effect of Environmental Factors on Larval Development of Crabs
                                                79
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                                            TEMPERATURE,  C

 Figure 2.  Comparison of minimum and maximum time of zoeal development (white), megalops development (stippled), and total development
         (block) to the first crab stage for larvae of S. cenereum reared under different salinities and temperatures.
is a  gradual reduction in the time of development
from  low  salinity  to high  salinity.   As with the
larvae of f. Aer&s ti, the duration of  the  individual
larval stages of S.  cinereum  at  30°C was approxi-
mately  half  the  time  required for comparable  de-
velopment when reared at 20°C.

   While data are not as complete as with the other
species  studied, Hepatus ephelittcus  larvae reared
under different conditions of salinity present a totally
different picture.  The adults of H. epheliticusv the
"box  crab," are  normally found in shallow offshore
waters  of  high  salinity  and are only occasionally
collected in the inlets leading to the bays and  estuaries.
Although  hatching  of the  larvae of H. ephelittcus
occurred at  all  five salinities  shown in  Table 1,
complete development to  the first crab  stage was
only  observed at 30 and  35  ppt.  At 30  and 40 ppt
the larvae did  not  live to complete the first zoeal
molt.   Survival  to  the first  crab stage was higher
at 35 ppt (13%) than at 30  ppt (3%). The rate of de-
velopment was also affected in the  lower  salinities:
at 25 ppt the time for development to the megalops
was 33 to 38 days, while at 30 and 35 ppt comparable
development  required 21 and  26  days, respectively.
   The  fifth species to  be considered, Callinectes
sapidus, presents still a different picture.  Although
the adult females are found in salinities  as low as
0.1 ppt, the majority  migrate  to  waters of higher
salinity prior to ovulation and the ovigerous females
are frequently  taken in  salinities  of from approxi-
mately  22  to  35 ppt.   Hatching of the larvae of C.
sapidus was observed at all experimental salinities
other than  10.5 and  15  ppt.  In water of 20.1 to 32
ppt.   The  zoeas hatched as first  stage larvae, and
the so-called "pre-zoeas was never observed. Com-
plete  development to the first crab  stage  occurred
in only three of the temperature-salinity combinations
shown in Table 1: 25 °C,  20.1,  26.7,  and 31.1 ppt.
There is some evidence that in  water of 32 ppt a
greater period  of time is required for complete de-
velopment to the first crab, but additional experiments
are needed  to confirm this.  While zoeal development
did not occur below 20.1 ppt more recent experiments
have  shown that the megalops  can complete meta-
morphosis  to   the  first  crab when  maintained in
salinities as low  as 5  ppt.   Preliminary results
suggest that in lower salinities a greater period of
time  is required  for  development of the megalops
than in the higher salinities.

-------
80
ENVIRONMENTAL REQUIREMENTS OF MARINE INVERTEBRATES
            Table 1.  SALINITIES AND TEMPERATURES UNDER WHICH LARVAE OF FIVE SPECIES
                              OF CRABS WERE REARED IN THE LABORATORY.

R. harrisi
P. herbsti
S. cinereum
H. epheliticus
C. sapidus
Temperature.
°C
20, 25, 30
20, 25, 30
20, 25, 30
25
20, 25, 30
Salinity,
°/oo
2.5, 5.0, 15.0, 25.0, 33.0, 35.0, 40.0
12.5, 20.1, 26.7, 31.1
12.5, 20.1, 26.7, 31.1
20, 25, 30, 35, 40
10.5, 15.6, 20.1, 26.7, 31.1
Number of
combinations
21
12
12
5
15
   Of the five species of crabs discussed, only  one
species  showed any  variation in number  of larval
stages.  C. sapidus  normally has seven zoeal stages
and  one megalops stage but in some experiments
an eighth zoeal  stage was found. This  "extra* stage
rarely  completed  development to the megalops  and
the few that did were never observed to metamorphose
to the first crab stage.   There is no evidence, how-
ever, that  these "extra" stages are associated with
either salinity or temperature.

           SURVIVAL OF CRAB LARVAE
   From laboratory  experiments on the rearing of
larvae, we  now  have relatively extensive data on the
effects of  salinity and temperature on the survival
of the  larval stages of three species: R. harrisi,
p. herbsti, and S.  cinereum.
                                      Experiments with larvae  of.R. harrisi have shown
                                   that  at  a salinity  of  1 ppt there  was no survival
                                   beyond  the second  zoeal  stage.   At  2.5  ppt none
                                   of  the  zoeal stages  reached the megalops at 20°C,
                                   but  at  25°C and  30°C  some did metamorphose to
                                   the first crab  (Fig. 3).  At 5 ppt there  was a greater
                                   survival at 25°C and 30°C than at 20°C. At salinities
                                   of  15,  25, and 33  ppt  there was a greater percent
                                   survival at 20° and 25°C than at 30°C (Figure 3).
                                   More recent experiments have shown that survival is
                                   even possible  at 40  ppt, although  the  percentage is
                                   considerably reduced. One of the remarkable features
                                   about the development of these crabs is the  relatively
                                   consistent high survival of  all four zoeal  stages to
                                   the  megalops  in the range  of salinity from 2.5 to
                                   33 ppt.  There  may be considerable mortality between
                                   the megalops stage and the first crab  stage in some
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                                              TEMPERATURE, C

 Figure 3. Percent survival to the megalops stage (white) and total survival to the first crab (black) for larvae of Rhithropanopeus harrisi
         reared at different salinities and temperatures.

-------
                    The Effect of Environmental Factors on Larval Development of Crabs
                                                                          81
salinity-temperature  combinations  but  even  so,  a
larger percentage of the  eggs laid  reach the first
crab stage than those of any species that has previously
been reared in the laboratory.
   The larval stages  of Panopeus herbsti  displayed
a similar  survival  (18%) in all salinities  other than
12.5 ppt, 30 °C (Figure 4). The highest per cent survival
was at the high temperatures and the lowest survival
was observed at 20°C.   There does not  appear to be
an  "optimum" salinity-temperature combination for
each  zoeal  stage  nor   was  any  one larval stage
particularly sensitive to any one salinity.

   Survival of the larval stages of S. cinereum was
definitely affected by salinity.  As shown in Figure 5
the first stage zoeae withstood the  higher salinities
(26.7 to 31.1 ppt) better than the lower salinities (12.5
to 20.1 ppt).  Mortality in the second and third zoeal
stages was relatively low  at  all salinities.  In the
fourth and  last zoeal stage,  however, 50 to  83 percent
of the total mortality occurred at a  salinity of 31.1
ppt, 30°C.  In most cases the zoeae died in the process
of molting  to the  megalops stage.

     ESTIMATION OF OPTIMUM CONDITIONS

   Although experiments on rearing of larval crabs
under different conditions of salinity and temperature
can contribute to our understanding of the environ-
mental factors that  affect development and survival,
                         it is physically  impossible to subject the larvae to
                         all the combinations  of salinity  and temperature in
                         which they  would conceivable be found under natural
                         conditions.   It is possible, however, by statistical
                         methods to postulate the response of larvae to a much
                         greater  variety  of environmental  conditions.  With
                         the  considerable assistance of Dr. R. Monroe,  De-
                         partment of Experimental  Statistics, North Carolina
                         State  College, Raleigh, N.C., we have attempted to
                         estimate the distribution and mortality of larval stages
                         of several  species at  the salinities and temperatures
                         of the natural environment.  The basic experimental
                         design used is  usually referred  to as  a factorial
                         design.   Specifically  the plan was a 3 x 4 factorial
                         in which  three levels of temperature and 4 levels of
                         salinity  were  used,  making a total of 12 different
                         combinations of  the experimental conditions.  If one
                         assumes  that the effects of temperature and salinity
                         are   continuous,   and  further  that a temperature-
                         salinity interaction may exist, then  the twelve experi-
                         mental combinations  may  be regarded as a  sample
                         in a continuum of temperature and salinity. One may
                         also postulate the existence of a  continuous response
                         (i.e., percent mortality) as a function of temperature
                         and  salinity, and  that either unique optimum com-
                         binations of the two factors may exist or that several
                         combinations of temperature and  salinity may produce
                         the same response. The estimation of this functional
                         relationship has  come to be  called  "the  fitting  of a
                         response surface" (Box and Youle,  1955).
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                                          TEMPERATURE,°C
   Figure 4. Percent mortality of each stage of P. herbsti reared at different temperatures and salinities.  SI - SIV = zoeal stages I  - IV;
           M= megalops.

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82
ENVIRONMENTAL REQUIREMENTS OF MARINE INVERTEBRATES
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   Figure 5. Percent mortality of each stage of S. cinereum reared at different temperatures and salinities. SI - SIV = zoeal stages I
          M= megalops.
                                                                               IV:
   We have attempted this treatment with data obtained
from  the  rearing  of  'S. cinereum and  P. herbsti
larvae, and are currently applying the same analysis
to our data on the effect of salinity and temperature
on development of R. harrisi  larvae.  More detailed
information on the treatment, as well as the results,
are available (Costlow,  Bookhout, and Monroe, 1960
and 1962).
   In  general, the  contours shown in Figures 6 to
10 represent the predicted values of  temperature
and salinity that would produce the mortality indicated
by the contour  lines.  It should be emphasized that
the usual dangers of extrapolation beyond the ranges
                                  of the observed data are as inherent in this method
                                  of prediction as in any other.  The significance levels
                                  chosen in  making  individual tests  of  significance
                                  were 5 percent, 10 percent, and 20 percent as the
                                  exploratory nature  of  this  study was  to  identify
                                  possible  leads  toward  important factors or  com-
                                  binations  of factors.  Effects that were significant at
                                  the 5 percent level were labeled as "marked effects,*
                                  while  those at  the  10  and 20 percent levels were
                                  denoted as "some effects."  T and  T2 were used to
                                  denote the linear and quadratic effects of temperature,
                                  S  and S2 the same for salinity, and (T X S) the inter-
                                  ation between salinity and temperature. A summary
                                  of these tests for the five  larval stages of Sesarma
                                  cinereum  is shown in table 2.
    Table 2.  SIGNIFICANCE OF SALINITY AND TEMPERATURE EFFECTS ON DEVELOPMENT OF
              THE FIVE LARVAL STAGES OF SESARMA CINEREUM REARED IN THE LABORATORY.
              T AND T2, LINEAR AND QUADRATIC EFFECTS OF TEMPERATURE:  S AND S2, LINEAR
              AND QUADRATIC EFFECTS OF SALINITY: T x S, INTERACTION OF TEMPERATURE
              AND SALINITY.  "MARKED EFFECTS" REPRESENTS SIGNIFICANCE AT THE 5% LEVEL
              AND "SOME EFFECTS" INDICATES SIGNIFICANCE AT THE 10% AND 20% LEVEL.

Stage I
Stage n
Stage m
Stage IV
Stage V
Marked effects
S


Sz, (T X S)
S
Some Effects
rp rp^
' O
S, T2
T, T2, S, (T X S)
S
(TXS)
Over-all
Correlation
0.872
0.742
0.829
0.877
0.847

-------
                   The  Effect of Environmental  Factors on Larval Development of Crabs
                                                                                              83
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                                      100
                                          10
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                                                          20
                                                     SALINITY, pp»
                                                                  25
                                                                          30
                                                                                  35
                                                                                          40
 Figure 6.  Estimation of percent mortality of first zoeal stage of S. cinereum based on the fitted response surface to observed
           mortality under twelve different combinations of salinity and temperature.
                   Ul
                   a.
                   ui
35
34
33
32
31
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                                          10
                                                  15
                                                          20
                                                                  25
                                                                          30
                                                                                  35
                                                                                          40
                                                   SALINITY, ppt
Figure 7.  Estimation of percent mortality of second zoeal stage of S. cinereum based on the fitted response surface to observed
          mortality under twelve different combinations of salinity and temperature.

-------
84
ENVIRONMENTAL REQUIREMENTS OF MARINE INVERTEBRATES
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       Figure 8.  Estimation of percent mortality of third zoeal stage of S. cinereum based on the fitted response surface to observed
                mortality under twelve different combinations of salinity and temperature.
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                                   '  I I I  '  I I  I  I I  I  I I  I I  I  I I  '  I I  '
                                                                                  '  ' I  I  I I  I  '
                                              10
                                                      15
                                                              20
                                                                      25
                                                                              30
                                                                                      35
                                                                                              40
                                                         SALINITY, ppt
      Figure 9.  Estimation of percent mortality of fourth zoeal stage of S. cinereum based on the fitted response surface to observed
                mortality under twelve different combinations of salinity and temperature.

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                    The Effect of Environmental Factors on Larval Development of Crabs
                                                                              85
                    u.
                    111
                    0-
                    2
                    UJ
35

34 h
33

32

31

30

29

28

27

26

25
24

23

22

21

20

19

18
17

16
15
                                       10
                                              15
                                                     20
                                                            25
                                                                   30
                                                                         35
                                                                                40
                                                 SALINITY, ppt
      Figure 10.  Estimation of percent mortality of megalops stage of S. cinereum based on the fitted response surface to observed
               mortality under twelve different combinations of salinity and temperature.
   The results of this treatment give detailed informa-
tion on predicted tolerance of the individual larval
stages, and also provide some general information on
larval distribution and survival. For example, the suc-
cessful completion of the life  history of S. cinereum
appears to depend largely on the fourth  zoeal stage.
That is, survival and  molting to the megalops can only
occur  in estuarine salinities.  Those that are carried
out to the higher salinities of the open sea, or trapped
in tide pools of higher salinity, would not be expected
to complete development.  Once  the megalops stage
is reached, however,  it can withstand the salinity of the
ocean  and a wide range of temperatures and it can
also survive in lower salinities at higher temperatures.
In contrast to larvae of S. cinereum, the larval stages
of P.  herbsti   can develop successfully in a wider
range  of salinities through all  stages of development.

   One may also hypothesize that the effect of tem-
perature on successive  larval stages limits the pro-
ductive spawning period of P. herbsti.   The "spring
brood" of larvae is favored by low water-temperatures;
larval  development is prolonged  until warming con-
ditions produce  a  favorable  environment  for  the
megalops stage.   Larvae that hatched during the fall
would  not  be  so favored by the gradual  reduction in
water  temperatures  and mortality in the late zoeal
stages and the megalops stage would be expected to
be extremely high.

   While numerous other comments would be possible
on the  ecological significance of these results and the
use  of this particular statistical treatment in studies
                              of biological  material, I will  conclude with this one
                              general  comment.  The  rearing of marine animals,
                              through  all larval stages to the pre-adult, provides
                              us with a tool for studies on morphology and taxonomy,
                              physiology, endocrinology, parasitology, and ecology,
                              which makes  possible  considerably  greater insights
                              into  the  basic  environmental and physiological re-
                              quirements of these  animals.  When  we acquire a
                              more complete understanding of the effects of environ-
                              mental factors  on rates of development, metabolic
                              activity,  and survival,  we  can  seriously consider
                              using some of these larvae  as extremely sensitive
                              bioassay  animals  for  laboratory studies on  water
                              quality and the  degree  of toxicity in estuarine and
                              marine environments.

                                             ACKNOWLEDGMENTS


                                 Figures  1  and 4 have been taken from "Salinity-
                              temperature effects on the larval development of the
                              crab, Panopeus herbsti Milne-Edwards, reared in the
                              laboratory",  Physiol.  Zoology  (Pub.  Univ.  Chicago
                              Press),  35:  79-93, 1962.  Castlow, J.D., Jr., C.G.
                              Bookhout, and R. Monroe.
                                 Figures 2,  5, 6, 7, 8, 9 and 10 have been taken from
                               "The effect of salinity  and temperature on  larval
                               development of Sesarma cinereum (Bosc) reared in
                               the  laboratory",  Biol.  Bull., 118:  183-303,  1960.
                               Castlow,  J.D.,  Jr.,  C.G. Bookhout and R. Monroe.

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86
ENVIRONMENTAL REQUIREMENTS OF MARINE INVERTEBRATES
                                            REFERENCES
Bousfield,  E.L., 1955,   Ecological  control  of  the
occurrence  of barnacles  in the Miramichi Estuary.
National Museum of Canada, Bull. 37.
Box, G.E.P.  and P.V. Youle,  1955.  The exploration
and  exploitation of response  surfaces:  An example
of the link between the fitted surface and the basic
mechanism of the system.  Biometrics,  11: 287-323.

Costlow, J.D.,  Jr.  and  C.G. Bookhout, 1959.   The
larval  development  of Callinectes sapidus Rathbun
reared in the laboratory. Biol. Bull., 116: 373-396.

Costlow, J.D.,  Jr.  and  C.G.  Bookhout, 1960a.   A
method for  developing  Brachyuran  eggs  in  vitro.
Limnol. and Oceanog., 5: 212-215.
Costlow, JJX,  Jr. and C.G.  Bookhout,  1960b.   The
complete  larval development of Sesarma cinereum
(Bosc) in the laboratory.  Biol. Bull., 118: 203-214.

Costlow, J.D.,  Jr.  and   C.G. Bookhout, 1961.   The
larval development of Eurypanopeusdepressus (Smith)
under laboratory conditions.   Crustaceana, 2: 6-15.
                                    Costlow,  J.D.,  Jr., C.G. Bookhout, and  R. Monroe,
                                    1960.  The effect of salinity and temperature on larval
                                    development of Sesarma cinereum (Bosc) reared in the
                                    laboratory.  Biol. Bull., 118: 183-202.

                                    Costlow,  J.D.,  Jr., C.G. Bookhout, and  R. Monroe,
                                    1962.    Salinity-temperature  effects  on  the  larval
                                    development of  the crab, Panopeus herbstii Milne-
                                    Edwards,  reared in the laboratory. Physiol.  Zool.,
                                    35: 79-93.
                                    Pearse, A.S.,  1936.   Estuarine animals at Beaufort,
                                    North  Carolina.  J.   Elisha  Mithell Sci.  Soc.,  52:
                                    174-222.

                                    Ryan, E.P. 1956.  Observation on the life histories
                                    and the distribution  of  the  Xanthidae (mud crabs)
                                    of the Chesapeka Bay, Amer.  Midi. Nat., 56: 138-162.

                                    Wurtz, C.B., and S.S.  Roback, 1955.  The invertebrate
                                    fauna of some  Gulf Coast rivers. Proc.  Acad. Nat.
                                    Sci. Philadelphia, 107: 167-206.
                            ENVIRONMENTAL REQUIREMENTS OF SHRIMP

                                              A. C. Broad *
   The shrimp fishery of the South Atlantic and Gulf
 coasts,  the most valuable  one  in the United States,
 began in its  present form with the application  of
 the otter trawl to  shrimp fishing sometime between
 1912  and 1915 (2). This fishery is based entirely on
 catches  of three species: Penaeus setiferus,(Linnaeus),
 Penaeus aztecus  Ives, and Penaeus duorarum Burken-
 road  (see Burkenroad (6) for systematic treatment).
 Catches are made in the Carolinas, Georgia, Florida,
 Alabama, Mississippi, Louisiana, and Texas. Related
 penaeids support important fisheries in other  parts
 of the world.
   Apart from their obvious economic  significance,
 penaeid  shrimp are of interest to zoologists because,
 unlike the  majority of higher  Crustacea  (to  which
 penaeids are  related),  they  offer  no  brood-pouch
 protection to their eggs, which they shed freely  in
 the  water.   The eggs usually  hatch within a day or
 less   (14, 23, 28, 29, 34).   The  first free-living form
 is a  nauplius, a stage typical of the life histories of
 phyllopods, copepods, barnacles, and other entamo-
 stracans, but usually passed in the egg in the develop-
 ment of malacostracans.
   Research on commercial shrimp in the United States
 began with the reports of Spaulding (37) and Viosca (40),
                                    (41) in Louisiana. In 1931 the U.S. Bureau of Fisheries
                                    started a research  program that has been continued
                                    to  the present.   Work is also in progress in state
                                    laboratories  and universities  in  all  the shrimp-
                                    producing states.  Reports have delt with life histories,
                                    larval development, systematics, distribution, and
                                    general ecology, but almost all have been fisheries
                                    oriented.    Until recently,  attention was  devoted
                                    largely to  P. setiferus,  the common white shrimp,
                                    which originally was the only species of commercial
                                    importance (42). As the  brown shrimp, P. aztecus,
                                    and the pink shrimp,  P.  duorarum, have become more
                                    abundant in the total landings, however, some scientific
                                    attention has been devoted to them.

                                        The life history  of the white shrimp is  fairly well
                                    known by  now.    The  following summary is based
                                    on the work of many investigators (1, 4, 5, 6, 7,13, 17,
                                    18, 29, 30, 31, 34, 42, 44, 46) who are now in more or
                                    less substantial agreement on generalizations.

                                        White  shrimp are  abundant in the United States
                                    from Cape Hatteras to  Cape Canaveral  and in the
                                    Northwestern and  Western Gulf of Mexico.   The
                                    adults spawn  at sea, probably over  the entire range
                                    of abundance, but usually in shallow, coastal water
 * The Ohio State University, Columbus, Ohio.

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                                   Environmental Requirements of Shrimp
                                               87
not in excess of 10 to 12 fathoms deep.  Well-defined,
seasonal spawning  suggests  a relationship with tem-
perature  on which  most authors are in agreement,
although specific effects of temperature on maturation
or release of eggs are poorly known.

   The  eggs, which are demersal  in sea water, are
probably shed while the parent shrimp is swimming
at some  intermediate  depth, as has been  observed
in Penaeus japonicus (28). They hatch within  12 hours.
The  newly hatched young, about 0.3  mm long, probably
pass through five  naupliar  stages in  1 day(34;,but
only three forms were found in Gulf of Mexico plankton
by  Heegaard (22).  The  nauplii subsist on  contained
yolk.   By  the  second day  the young  shrimp are in
the  first of three  so-called protozoeal stages and
feed  for the first time.  The protozoeal phase may
last until the sixth  day  after hatching by which time
the  larvae  are  in  the  first of two  (possibly three)
so-called mysis  stages.  Metamorphosis to the  post-
larval  stage occurs on  the  tenth to  twelfth day, but
the young postlarvae, now about 4.2 mm long, remain
planktonic.   Postlarvae  of  related penaeids (23, 28)
molt every other  day,  and  this may be reasonable
estimate of the molting frequency of very young white
shrimp.  The larvae are found in oceanic  plankton,
presumably in  the  general  area in  which  spawning
occurs.  Postlarvae of about  6 to 7 mm in total length,
however, are  abundant  in  and  around inlets and
estuary mouths.   These individuals are in at least
the second postlarval molt cycle. By means not under-
stood but presumably by using tidal currents (45), the
young shrimp  make their  way  to the less saline,
shallower  portions  of  estuaries where they adopt a
benthonic existence, usually on muddy substrates.


   Growth  of juvenile  shrimp is rapid.   Estimates of
this growth are based on three different procedures,
each of which contains  intrinsic bias: the advance of
modes  are limits in subsequent length-frequency dis-
tributions,  observed growth of  captive individuals,
and  growth of  tagged  individuals.  On  the basis of
length-frequency  data,  Williams  (44)  estimates  a
growth rate of 36 mm per month for shrimp of about
70 mm total length.  Lindner and Anderson (31), based
on the  results  (and extrapolations  thereof) of tagging
experiments, consider  the length increment to be 80
mm  in the first  2 months, 25  mm  a month at an
average size of 100 mm, and 15  mm  a month at an
average size of 125 mm.   Growth estimates based
on observations of postlarval shrimp in aquaria are
on  the  order of 20 mm per month (34). All growth
estimates have  been made for summer temperatures
or  are based on  summer populations.   Growth and
other activities are retarded by cold.


   According to  the length-frequency plots of Lindner
and  Anderson (31), Louisiana white shrimp  about 140
mm in  length are sexually mature,  but it is  a curious
fact that minimum sizes of mature  white shrimp have
not been reported.  Based on available growth data,
white shrimp living in warm water would be sexually
mature at an age of about 6 months.  Gunter (17) based
a similar conclusion on length-frequency data.  The
largest  white  shrimp  may be  200 mm long, but
growth, after about 18  months, is  negligible.  There
now  seems  to  be  general  agreement  that  white
shrimp  may spawn repeatedly in a single year  and
may live longer than 1 year.

   Growth  of juvenile   shrimp  is  accompanied  by
movement back toward water of higher salinity. Cor-
relations of size and salinity, at least within narrow
ranges, have not been demonstrable, however. Maturing
shrimp  leave estuaries at all seasons of the year,
but there  is a general, and evidently temperature-
related,  exodus  of all  but  the  smallest shrimp in
autumn.   Juveniles may overwinter in dormancy in
estuaries.

   Lindner  and  Anderson (31)  report a southward
coastwise  migration  of  Atlantic  white  shrimp in
autumn and northward migration in the spring. There
are corresponding seaward-shoreward movements in
the Gulf.

   Until recently,  relatively  little was known of the
life  history of the pink shrimp, P. duorarum.  The
following  is  based largely  on  the  work of  several
investigators  (4, 6,  7, 10,  14, 15, 24,  25, 44, 46).

   Pink shrimp are abundant  in North Carolina (where
they are not pink) and  in the eastern Gulf of Mexico
and occur  in the remainder  of the shrimp-producing
region.   The adults  spawn  at  sea  in water usually
less than  28  fathoms  deep and  possibly  only at
temperatures  in  excess of  24°C (15).  The  larvae
resemble  those  of the  white shrimp and, like them,
are members of  the ocean plankton. There are five
naupliar  stages,  three  protozoeal forms,  and three
mysis forms.  The eggs hatch  within a day, and the
nauplier phase lasts only 24  hours(14).The frequency
of subsequent molts is  unknown. The poltlarvae are
about 4 to  5 mm long  at the time of metamorphosis
and  still   members of  the  ocean plankton.   They
subsequently enter estuaries and  have been  found
on nursery grounds in  North Carolina at lengths of
17 mm or less  (43,44). The nursery areas  of pink
shrimp may be more saline and have coarser sedments
than those of white shrimp.

   Growth  is  rapid.  Various estimates from 20 to
52 mm per month have been based on length-frequency
distributions.  Eldred et al(l5)estimates an average
lenght  of  75  mm after 4 months, 133 mm after 10
months,  and  142  mm  after  1  year. Williams (44)
suggests a growth increment of 52  mm per month
for juveniles.  Cummings (10) found  sexually mature
pink shrimp  93  mm long.  According to the available
growth  data,  these may  have been on the order of
6 months  old.  The largest individuals, however,  are
about 200 mm long and of unknown age.

   The  shrimp  move   seaward as  sexual maturity
approaches.   The  largest adults are always found
some distance from shore.   Unlike P. setiferus,
which is diurnal,  P. duorarium is  nocturnal in habit
and usually burrows into the bottom during the day-
light hours.

   Almost  nothing is known  of the  life history of P.
aztecus, the brown shrimp, but there is little  reason
to suspect that  the generalities  of its  life  history

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88
ENVIRONMENTAL REQUIREMENTS OF MARINE INVERTEBRATES
differ markedly from those of other penaeids.  Brown
shrimp are abundant from North Carolina to Florida
on  the Atlantic  Coast and  in  the  western  Gulf of
Mexico.   Williams (44, 45) and Bearden (3) found post-
larvae abudant  in  the Carolinas from January  or
February through May or June and present all during
the summer.  Gunter^ 7)found small juveniles during
most of the year in Texas, and Pearson (34) reported
planktonic postlarvae, presumably of this species, year
around in Florida and  Louisiana.  The young prefer
nursery areas more saline than those of white shrimp
(18). The brown shrimp also prefer nursery areas with
mud  bottoms  (46).  Growth  of juveniles has  been
estimated at about  45  mm per month by Williams (44).
Adults 200 mm long are not uncommon.  Burkenroad
(^states  that,  after a littoral youth,  brown shrimp
retire  permanently to deeper water offshore. Spawning,
at least in the Gulf, may occur almost continuously.
P. aztecus shows some tendency toward the nocturnal
habit of P. duorarum (29).

   In spite of the  general similarities  in  the life
histories  of commercial  shrimp,  there are probably
specific  differences.   These differences are still
difficult  to define,  except generally.   Springer and
Bullis (38, 39) and Hildebrand (24, 25;found differences
in the  distribution of  adults  in  the Gulf:  They found
white and brown shrimp on terrigenous silt bottoms,
and pink shrimp on coral sand and shell. White shrimp
occur mainly inshore of the 10 fathom curve, and brown
shrimp offshore of  it.  White and brown shrimp are
found largely in the western  Gulf, and pinks are ap-
propriate bottoms in the  eastern  Gulf. The inverte-
brate and fish associates of the pink and brown shrimp
differ (24,25). Similar separation of adult populations
occurs in the Atlantic (4).

   The distribution  of shrimp  in the Gulf  may be
associated  with  differences  in the nursery  areas
adjacent  to  the  eastern and  western portions.
Hildebrand (25) suggests  that a  combination  of low
salinity and mud bottom  may bar P. duorarum from
Louisiana  west of the Mississippi, but Springer and
Bullis (38) and Darnell and Williams (12) found a few
pink shrimp in  Louisiana.  Gunter (18) suggests  that
salinity of Texas  nursery areas may  be optimal for
P. aztecus  and that  of  Louisiana estuaries for P.
setiferus.  Williams (46) demonstrated that, if offered
a  choice, young  pink  shrimp  will  select  coarse
substrates and young  whites  and browns will settle
on mud.

   In  spite of the  obvious  significance  of  salinity
to shrimp life  histories, the relationship becomes
extremely confusing when one attempts to do more
than generalize. All investigators agree that smaller
individuals  occur in  lower  salinities, but attempts
to demonstrate a  relationship  have met with little
success (31).   Gunter (17) treats salinity in  broad
ranges: less than20o/oo; 20to29.9o/oo; and 30+o/oo,
and shows a graphic relationship between size of white
shrimp and these three salinity ranges. The smallest
shrimp, however, occur at all salinities and Gunter
himself (18) cites a  collection of white shrimp 15 to
66 mm long from the Laguna Madre  in Texas taken
at a salinity of 41.3 o/oo.   Williams (45) reports the
salinity  of nursery  areas   in  North  Carolina as
                                    "nearly  fresh  to 37  o/oo." Johnson and Fielding(29)
                                    reared P. setiferus  postlarvae at 31.2 to 37.1  o/oo
                                    and,  in  one experiment,  obtained better growth at
                                    34 o/oo than at 18.5 o/oo.   LunzfS^reared juvenile
                                    white shrimp at 17.6 to 33.2 o/oo.

                                       Data  on  salinity  relations  of pink  and brown
                                    shrimp,  though fewer, are equally inconclusive. Darnell
                                    and Williams (12) took juvenile P. duorarum from Lake
                                    Pontchartrain, Louisiana, where the salinity range was
                                    of 3.9 to 10.3  o/oo.  Williams^; although he did not
                                    mention  salinities  of  specific collections, found
                                    juveniles of all species within his range of nearly
                                    fresh to 37  o/oo, occupying the same nursery areas,
                                    but mainly  at  different times of the year. Gunter
                                    (17) took  4,201 brown  shrimp from water  of  less
                                    than  10 o/oo,  7,510 from  water  of  10 to 20 o/oo,
                                    2,920 from water 20 to 30 o/oo, and 1.010 from water
                                    of 30+ o/oo salinity. These  data illustrate the hope-
                                    lessness of  relating the available collection data to
                                    the effects of  salinity on  shrimp.  More  acceptable
                                    is the  estimate of Gunter (18) that optimum salinity
                                    for juvenile P. setiferus  is  less  than 10 o/oo  (and,
                                    presumably, that the optimum salinity for P. aztecus
                                    nursery areas is in excess  of 10 o/oo).  Hildebrand
                                    (25) suggests  an  optimal salinity of approximately
                                    20 o/oo for P. duorarum nursery areas.  By far the
                                    most satisfactory demonstration of a relationship be-
                                    tween salinity and species of shrimp is a correlation
                                    between the catch of white shrimp in Texas with the
                                    annual rainfall for the previous 2-year period (19,26).

                                       The work of Hudinage (28) on larval P. japonicus
                                    and that of Rao (35) on an Indiana penae id, Metapenaeus
                                    monoceros,  shed  some light on  salinity relations.
                                    Absolute values are not important to this discussion,
                                    but a definite  range of salinity within which post-
                                    larval P. japonicus were able to survive was demon-
                                    strated  by  Hudinaga.   Rao  determined  oxygen  con-
                                    sumption of M. monoceros of various sizes when sub-
                                    jected to  sudden changes in salinity.   His material
                                    was obtained from water of either 33.5 o/oo or  from
                                    20 o/oo  salinity and subjected to salinities of 33.5
                                    o/oo,  16.75  o/oo,  and 8.4 o/oo, and to   tap  water.
                                    In each  case of osmotic stress, oxygen consumption,
                                    as might  be  expected, increased, but the increase
                                    was inversely proportional to the  size of the shrimp.
                                    Thus, juveniles  placed in  water of salinity other than
                                    that in which  they were collected were in a greater
                                    stress  situation than were adults similarly treated.
                                    Although salinities other than those within an optimal
                                    range may  not  kill  shrimp, the  osmotic stress so
                                    imposed may  result in increased  energy demands
                                    on juveniles.

                                       Some temperature effects on shrimp are well known,
                                    and some  other  data have  been presented.    Cold
                                    will kill shrimp(79, 31, 33), but rapidity of temperature
                                    change  seems  to  be more  important than the  final
                                    temperature. (19)  Eldred  et al. (15) report  that P.
                                    duorarum were killedby 12.8°C in tanks andnarcotized
                                    at 13.3°C, but Williams (45)  found the same species
                                    living at 4°C, but inactive below about 15°C.  Lindner
                                    and Anderson(31) suggest that growth of white shrimp
                                    does not occur below 20°C.  Spawning of all species
                                    is probably associated with temperature or with trends
                                    in temperature, as  are movements and  migrations

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                                  Environmental Requirements of Shrimp
                                                                                                    89
(31), but specific effects are unknown.   There are no
data on effects of high temperatures on U.S. penaeids.
Scholander et sii.(36)found that P.  brasiliensis (pre-
sumably collected in Panama) did not survive at 35°C
in closed respirometers, but Williams (45) and Lunz
(32) found shrimp living at 35° and 36°C. Scholander's
value of 35°C may have little meaning outside of the
respirometer flask, but is significant that the range
of temperatures within which  his shrimp survived
(15° to 30°C) was narrower than that of other tropical
crustaceans tested.   Q10 values,  defined as the  rate
of change (slope) at giving temperatures of the curve
of oxygen consumption plotted against temperature,
were uniform (2.4) from 15° to 25°C, but decreased
(1.7)  at 30°C.   Tropical P. brasiliensis,  thus, is
active within  a relatively narrow temperature range.
The   similarity   of  the lower  activity limit  of P.
brasiliensis to those observed by Williams and Eldred
et al. on cold narcosis of P. duorarum may indicate
similar thermal limits in U.S. penaeids. The reported
observations of temperatures at which shrimp are  col-
lected seem to support this.

   Shrimp are considered omnivorous by most authors.
Weymouth et  al.(42) observed cannibalism in captive
shrimp.  Foods reported either after  observation or
as  a  result  of stomach analysis are  listed  with
references:
                              (15, 16)
                              (15, 34, 44)
                              (28)
                              (15)

                              (11, 15,16, 44)
                              (15)
                              (11, 44)
                              (16)
                              (16)
                              (16)
                              (15)
                              (15, 44)
                              (34)
Blue-green algae
Green algae
Diatoms
Red algae
Leaves  and other parts of
   vascular plants
Dinoflagellates
Faraminiferans
Sponge
Coral
Bryozoans
Nematodes
Polychaetes:  jaws, setae
Angleworms
Crustaceans, mandibles,
   chitin fragments, water
   fleas, copepods, ostracods,
   mysids, isopods, amphipods,
   penaeid shrimp, shrimp
   eggs, caridean shrimp,
   shrimp meal, Artemia
   nauplii                  (11, 15, 23, 28, 44, 46)
Insect remains             (11)
Molluscs: shells, squid
   suckers                 (11, 15, 44)
Fish:  whole fish, fish meal,
   fish eggs,  ribs, eyes,
   scales                  (15, 29, 34, 44)
   All  authors  who have examined shrimp stomachs
report organic debris and sand.  Williams (44) found
stomachs  of juveniles  empty  in  winter but always
half full to full in the autumn.

   Although there is tacit  agreement that the oxygen
requirements  of white shrimp are higher than are
those of browns or  pinks (46), no studies of oxygen
consumption by U.S. penaeids have been attempted.
Rao (35) has shown higher consumption per  gram in
young Metapenaeus in situations of osmotic imbalance.
Scholander  et  al. (36) obtained oxygen  consumption
values for P. brasiliensis not significantly different
from  those  of  other tropical  crustaceans tested, but
noted a marked decrease in rate of oxygen consumption
in closed respirometers at 30°C.

   Butler (8) and Chin and Allen (9) have reported on
the effects  of insecticides on commercial  shrimp.
The data presently  at hand  indicate toxic  effects
of  Endrin,  Sevin,  DDT,  Dieldrin, Toxaphene, TDE,
and Heptachlor  in order  of  decreasing  toxicity.
Butler (8) reports tolerance limits of medium-sized
P.  aztecus  ranging from only 2.5 ppb Edrin  to 700
ppb Heptachlor.   Smaller  shrimp  and postlarvae
evidently are more sensitive.  White shrimp generally
show less resitance than browns.

   By  way of summary it might be pointed out that
although we now  seem to know a great  deal about
the life histories of commercial shrimp the informa-
tion at hand is  not sufficiently specific to talk, other
than in general terms, about environmental require-
ments.   All authors agree that there are two critical
periods in the  life history: the so-called first proto-
zoeal stage when feeding commences and the postlarval
period or early juvenile phase when the young shrimp
are  found  in  brackish,  estuarine nursery areas.
Available studies indicate possible specific differences
in  environmental  requirements  during  the  juvenile
phase.   P.  setiferus,  which  has  been shown to be
most sensitive to some insecticides, evidently prefers
(or is  able  to survive better in) low-salinity nursery
areas.  It is likely that oxygen utilization is also high-
est at this time, when the shrimp are in waters most
likely to be polluted by industrial or domestic wastes,
by  run off  from  the  land, or by insecticides from
control programs.   P. aztecus,  which is evidently
somewhat better able to withstand at least some kinds
of pollution and probably has an overall lower oxygen
requirement than the white shrimp, is also successful
in somewhat higher salinities  or rears successfully
farther from terrestrial run-off than the white shrimp.
P.  duorarum  may represent a still  further step in
this progression, but this has  not been demonstrated.
On  the basis of  available  information, it does not
seem unreasonable to assume that P. setiferus and
P. aztecus are  competitors during all or a good part
of their lives.   Such  statements have been  made
by  Williams (45) for nursery areas and are  implicit
in the  writings of Gunter  and  Hildebrand  (19,26).
P.  setiferus  cannot  compete  with   P.  aztecus in
high-salinity nursery areas 18  and may be less able to
survive reduced oxygen tension or pollution  as well.

   Weymouth et al. (42) and Anderson etal. (1) estimated
that the overall catch of the  shrimp fishery  of the
South  Atlantic and  Gulf was  95 percent P. setiferus
in the  years  perior to  1949.  As long ago as 1950
a change in the shrimp catch  in North Carolina was
noted  (4). By associating  species caught with time of
the year, we were able to  show  that the catch had
changed from predominantly white shrimp during the
5-year  period  1940 through  1944 to  predominantly
brown shrimp inthe periodfrom 1945 to 1949  (17,21).

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   90
ENVIRONMENTAL REQUIREMENTS OF MARINE INVERTEBRATES
   Until about 1948 the bulk of the shrimp catch in the
   Gulf  of Mexico  was  P. setiferus, but in the years
   between 1948  and 1953  there  was a  decline in the
   abundance of  white  shrimp  (17,21). Hildebrand (24)
   comments on the decline of the white shrimp landings
   in  Lousiana and Texas  and the  increased landings
   of  brown  shrimp  in  Texas  after 1948. Gunter (18)
   similarly  compares white and brown shrimp landings
   in  the  western  Gulf, which he relates to  salinity
   differences between estuarine  nursery  areas in
   Louisiana and Texas.  The increased catches of brown
   and pink shrimp may be  largely a reflection of the
   opening of new grounds as suggested by  Hedgepeth
   (21) but the overall decrease in the population of white
   shrimp is real.  It seems reasonable to consider the
   possibility that slight changes in nursery areas may
   have  occurred since the mid-1940's.   The available
                                    data  suggest  that  increases  in salinity (possibly
                                    associated  with  decreased rainfall), decreases  in
                                    oxygen (possibly resulting from increased demands
                                    on the environment by domestic  or industrial organic
                                    wastes), or increases in the concentration of pesticides
                                    (associated with increased agricultural use of insecti-
                                    cides)  would be disadvantageous to P. setiferus  or
                                    might  give  the  relatively  hardier  P. aztecus  an
                                    advantage over  the  white  shrimp.   The magnitude
                                    of change that could be effective, although presently
                                    impossible to estimate, presumably  could be  very
                                    small.    In view of the  importance of the resource
                                    it  seems that  the  area of  competition between the
                                    species  is  a critical  one  as  is  the obvious need
                                    for  better understanding of the basic physiological
                                    effects of the environment, especially on the juvenile
                                    shrimp.
                                               REFERENCES
 I.Anderson, W.W.,  J.E. King and M.J. Lindner, 1949.
   Early  stages  in  the  life  history  of  the  common
   marine shrimp,  Penaeus setiferus  (Linnaeus). Biol.
   Bull., 96: 168-172.

 2.Anderson, W.W.,  M.J.  Lindner and J.E. King, 1949.
   The  shrimp fishery of  the Southern United States.
   U.S. Fish and Wildlife Service, Commercial Fisheries
   Review, 11: 1-17.

 S.Bearden, C.M., 1961.  Notes  on postlarvae of com-
   mercial shrimp  (Penaeus)  in South Carolina. Bears
   Bluff Laboratory Contrib. No. 33: 3-8.

 4. Broad, C., 1950.   Results of shrimp research in
   North  Carolina.   Proc.  Gulf and  Caribbean Fish
   Inst., 3rd annual session, 1950.

 5-Burkenroad, M.D, 1934.  The Penaeidae of Louisiana
   with  a discussion  of their world relationships.  Bull.
   Amer. Mus. Nat. Hist., 68: 61-143.

 6.Burkenroad, M.D., 1939.  Further observations  on
   Penaeidae of  the  Northern Gulf of  Mexico.  Bull.
   Bingham, Oceanogr. Coll., 6:1-62.

 7.Burkenroad, M.D., 1949. Occurrence and life histories
   of commercial shrimp. Science, 110:688-689.

 S.Butler, P.A., 1962. Effects on commercial fisheries
   in  effects of pesticides on fish and wildlife:  a review
   of investigations during 1960.  U.S.  Fish and Wildlife
   Service,  Bureau   of Sport  Fisheries and  Wildlife,
   Circular No. 143.

 9. Chin, E. and M.D. Allen, 1957.  Toxicityof  an insecti-
   cide  to two species of shrimp, Penaeus aztecus and
   Penaeus setiferus. Texas J. Sci., 9:270-278.

lO.Cummings, W.C.,  1961.  Maturation and spawning of
   the pink shrim, Penaeus duororum Burkenroad. Trans.
   Amer. Fish. Soc., 90:462-468.

11. Darnell, R.M., 1958.  Food habits of fishes and larger
   invertebrates  of  Lake Pontchartrain,  Louisiana,  an
   extuarine community.  Publ. Inst. Marine Sci., Texas,
   5:353-415.
                                 12. Darnell.  R.M. and A.B.  Williams,  1956.   A note on
                                    the  occurrence of the pink shrimp Penaeus duororum
                                    in Louisiana waters.  Ecology, 37:844-846.

                                 13. Dawson,  C.E., 1957.   Balanus  fouling of shrimp.
                                    Science, 126:1068.

                                 14. Dobkin,  S., 1961.  Early developmental stages of pink
                                    shrimp,  Penaeus  duororum from Florida waters.
                                    Fishery Bull. U.S. Fish & Wildlife Serv., 61:321-349.

                                 15. Eldred,  Bonnie,  R.M.  Ingle,  K.D. Woodburn,  F.F.
                                    Button and Hazel Jones, 1961. Biological observations
                                    on the commercial shrimp, Penaeus duororum Burken-
                                    road,  in Florida waters. Fla. State Bd. Cons., Profes-
                                    sional Paper Series No. 3:1-139.

                                 16. Flint, L.H., 1956.  Notes on the algal food of shrimp
                                    and oysters.  Proc. La. Acad. Sci., 19:11-14.

                                 17. Gunter,  G., 1950.  Seasonal  population changes  and
                                    distributions  as related to salinity, of certain in-
                                    vertebrates  of the Texas coast,  including the com-
                                    mercial  shrimp.  Publ.  Inst. Marine  Sci, Texas,
                                    1:7-51.
                                 18. Gunter,  G., 1961. Habitat of juvenile  shrimp (Family
                                    Penaeidae). Ecology, 42:598-600.

                                 19. Gunter,  G.  AND H.H.  Hildebrand, 1951.  Destruction
                                    of fishes and other organisms  on the South Texas
                                    coast  by the  cold wave of January 28 - February 3,
                                    1951.  Ecology, 32:731-736.
                                 20. Gunter,  G.  and H.H.  Hildebrand,  1954.  The relation
                                    of total  rainfall  of the state  and catch of the marine
                                    shrimp  (Penaeus  setiferus) in  Texas waters.  Bull.
                                    Marine Sci. Gulf and  Caribbean, 4:95-103.

                                 21. Hedgepeth,  J.W.,  1953.  An introcuction to the zoo-
                                    geography of  the northwestern Gulf  of Mexico with
                                    reference to  the  invertebrate  fauna.  Publ.   Inst.
                                    Marine Sci., Texas, 3:111-224.

                                 22.Heegaard, P.E.,  1953.  Observations  on spawning
                                    and larval history of  the shrimp,  (Penaeus setiferus)
                                    (L.) Publ. Inst. Marine  Sci., Texas, 3:73-105.

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                                    Environmental Requirements of Shrimp
                                                  91
23.Heldt,  Jeanne  H.,  1938.   La reproduction chez les
   crustaces  decapodes  de la famille  des Peneide
   Ann. Inst. Oceanogr., Monaco, N.S. 18:1-206.

24.Hildebrand, H.H., 1953.   A study of the fauna of the
   brown  shrimp  (Penaeus  aztecus)  grounds  in the
   western  Gulf  of  Mexico.  Publ. Inst. Marine Sci.,
   Texas, 3:233-366.

25.Hildebrand, H.H., 1954.   A study of the fauna of the
   pink shrimp (Penaeus duororum Burkenroad) grounds
   on the Gulf  of Campeche.  Publ. Inst. Marine Sci.,
   Texas, 4:171-232.

26.Hildebrand, H.H.  and G.  Gunter, 1953.   Correlaton
   of rainfall with the  Texas  catch  of white shrimp,
   Penaeus setiferus (Linnaeus).  Trans. American Fish.
   Soc., 82:151-155.

27 Hoese, H.D., I960.   Juvenile  penaeid shrimp  in the
   shallow Gulf of Mexico.  Ecology, 41:592-593.

28.Hundinaga, M., 1942. Reproduction, development and
   rearing of Penaeus japonicus Bate. Japanese J. Zool.,
   10:305-393.

29.Johnson,  M.C.  and  J.R.  Fielding, 1956.  Propagation
   of the  white  shrimp,  Penaeus setiferus (Linn.) in
   captivity.  Tulane Stud. Zool., 4:175-190.

SO.King, J.E., 1948. A study of the reproductive organs
   of the  common marine  shrimp,  Penaeus  setiferus
   (Linnaeus).  Biol. Bull., 94:244-262.

31.Lindner,  M.J.  and  W.W. Anderson, 1956.   Growth,
   migrations, spawning and size distribution of shrimp
   Penaeus  setiferus.  Fishery Bull.  U.S. Fish and Wild-
   life Service, 56:555-645.

32.Lunz,  G.R.,  1956.   Harvest from an experimental
   one - acre salt-water pond at Bears Bluff Laboratories,
   South Carolina.  Progressive FishCulturist,  18:92-94.

33-Lunz, G.R., 1957. Pond cultivation of shrimp in South
   Carolina.   Proc. Gulf  and Caribbean  Fish. Inst. for
   1957.

34.Pearson, J.C., 1939. The early life histories of some
   American Penaeidae, chiefly the  commercial shrimp
   Penaeus  setiferus  (Linn.).   Bull.  U.S. Bur.  Fish.,
   49:1-73.
35.Rao, K.P., 1958.  Oxygen consumption  as a function
   of size and salinity in Metapenaeus monoceros Fab.
   from marine  and brackish water  environments.  J.
   Exper. Biol., 35:307-323.

36.Scholander, P.F., W. Flagg, V. Walters and L.Irving,
   1953.   Climatic adaptation in  arctic  and tropical
   poikilotherms.  Physiol. Zool., 26:67-92.

37.Spaulding, M.HL, 1908.  Preliminary report on the life
   history and habits of  the "lake shrimp."  Bull.  Gulf
   Biol. Station, 11:1-29.

38. Springer,   S.  and H.R.  Bullis,  1952.   Exploratory
   shrimp fishing in the  Gulf  of Mexico, 1950-51.  U.S.
   Fish and Wildlife Serv. Fish Leaflet 406.


39. Springer,   S.  and H.R.  Bullis,  1954.   Exploratory
   shrimp fishing  in  the  Gulf  of Mexico,  summary
   report  for  1952-54,  U.S.  Fish and  Wildlife Serv.
   Commercial Fish. Review, 16:1-16.

40.Viosca, P.,  1920.   Report of the Biologist, Dept.
   Cons. La.,  4th Bienn. Kept.  :120-130.

41.Viosca, P., 1923.  In  E.A.  Tulian, the present status
   of the  Louisiana shrimp industry.   Trans. Amer.
   Fish. Soc., 42:110-121.

42.Weymouth, F.W., M.J. Lindner and W.W. Anderson,
   1933.  Preliminary  Report on the life history of the
   common shrimp, Penaeus setiferus(Linn.). Bull.  U.S.
   Bur. Fish., 48:1-26.

43. Williams,  A.B., 1953.   Indentification of juvenile
   shrimp (Penaeidae)  in  North Carolina.  J. Elisha
   Mitchell Sci. Soc., 69:156-160.

44. Williams,  A.B.,  1955.   A contribution to the  life
   histories of commercial shrimps (Penaeidae) in North
   Carolina.   Bull. Marine Sci., Gulf and Caribbean,
   5:116-146.

45. Williams,  A.B.,  1955.   A survey of North Carolina
   shrimp Nursery grounds.   J. Elisha Mitchell  Sci.
   Soc., 71:200-207.

46. Williams,  A.B.,  1958.   Substrates as a  factor  in
   shrimp distribution.    Lirnnol.  and Oceanogr.,  3:
   283-290.

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92
ENVIRONMENTAL REQUIREMENTS OF MARINE INVERTEBRATES
            REACTION OF ESTUARINE MOLLUSKS TO SOME ENVIRONMENTAL  FACTORS

                                            Philip A. Butler *
                  INTRODUCTION
   For  nearly 25 years,  this laboratory has been
concerned  with identifying the environmental factors
that permit our commercial species of mollusks to
fluorish.   Studies have been conducted of Santa Rosa
Sound, Florida, in adjacent areas known to be suitable
for  oysters but  which  support  a relatively small
commercial harvest because of the high concentration
of natural  predators.  Santa Rosa  Sound is approxi-
mately 40 miles long and presents a typical estuarine
habitat,  although  it has  two openings into the  Gulf
of Mexico.  Land drainage into the Sound is sufficient
to  cause marked seasonal and tidal  fluctuations in
salinity.
   In the past, too many biological studies on oysters
have  been in  the nature of crash programs, limited
in time  and,  more often than not,  concerned with
elucidating problems that had  ceased to exist. The
convenience of  this  location and the presence of a
permanent staff made it  possible to  initiate a long-
term program to observe  the normal range of environ-
mental factors in conjunction with the fluctuations in
a natural population of oysters.
                                   oyster population  associated  with specific changes
                                   in the physical or chemical environment. This report
                                   is a brief summary of some  of our observations in
                                   the past decade, what the environment has offered,
                                   and  how  the oyster  and other  estuarine animals
                                   have responded.


                                              ENVIRONMENTAL CONDITIONS
                                      There  are certain classical parameters used to
                                   characterize the estuarine environment and we did not
                                   neglect these  while  searching  for  more  obscure
                                   factors.   Continuous  recordings  of fluctuations in
                                   water temperature have been maintained since 1947.
                                   Water samples have been collected at 4-hour intervals
                                   and titrated for total salts with Collier's water sampler
                                   (1953)  for as long a period.  Graphical summaries
                                   of these data show the average picture for the years
                                   1951 through 1960 (Figure 1).  Figure 2  shows the
                                   data for  1959, the year of lowest average salinity,
                                   and  Figure  3 shows  1954, the  year of both highest
                                   temperature and highest salinity in the 10-year period.
                                   Other specific factors in the environment were scanned
                                   from time to time, and these are considered in dif-
                                   ferent sections of this report.
   The unique  facility of estuarine animals to adjust
physiologically  to  more  or less drastic environ-
mental changes does not imply that they are equally
successful under all conditions, but only that sufficient
numbers  survive to perpetuate the species.  This
was well demonstrated about 15 years ago when the
upper  Chesapeake  Bay  experienced a protracted
period of flooding that extended into the mid-summer
months.  The  oysters become, quite literally,  bags
of water and contracted perhaps a third in body  size.
Still,  a very  few  managed  to  elaborate gametes,
there  was a  late summer spawning, and the brood
survived (Butler, 1949).

   Our studies  in Florida have undertaken the col-
lection of 'routine' data to determine what are normal
conditions, and to delineate if possible, changes in the
                                                         GROWTH


                                      The most easily measured response of the animal
                                   to its surroundings is  its growth,  and the rate at
                                   which it  grows may be of fundamental importance in
                                   evaluating  the environment.    One  of  our earlier
                                   studies  (Butler,  1952)  reported the seasonal  per-
                                   centage increase in length of a small  population of
                                   oysters.   These oysters, collected when less than a
                                   millimeter in length at metamorphosis, were observed
                                   as individuals for more than 3 years. Table 1 shows
                                   their seasonal increments and the change in the pattern
                                   of growth as they aged. When juveniles the greatest
                                   growth was in the summer.   In their  second year,
                                   there was an emphasis on winter growth, and in their
                                   third  year almost no growth took place in the warm
                                   summer months.
* Director, Bureau of Commercial Fisheries Biological Laboratory, Gulf Breeze, Florida.

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                   Reaction of Estuarine Mollusks to Some Environmental Factors
                                                                                             93
               28
               26
               24
             >-

             z
               22
               20
               18
                                        NOV
                                                                        SEPT
                                                                  MAY
                                                  APR
                  10    12     14     16     18    20    22     24
                                            TEMPERATURE,0°C
                                                                    26
                                                                          28
                                                                                30
                                                                                      32
 Figure 1. Comparison of the monthly water temperature and salinity in Santa Rosa Sound.  Data are averages of continuous
         temperature recordings and titrated salinity samples collected at 4-Hour intervals from 1951 through 1960.
                    Table 1.  SEASONAL PERCENTAGE INCREASE IN LENGTH
                              OF A SMALL POPULATION OF OYSTERS
Age of
oysters,
years
1
2
3
Percent of annual increment
June-September
46
14
11
October -January
36
52
68
February-May
18
34
21
               30


               28
Z22
_i
3 20

  18

  16
         JAN
                                MAR
                                                  APR
                                                                                   AUG
                                                                                    JULY
                                                                             JUNE
                  10     12      14      16     18     20     22     24
                                             TEMPERATURE, 0°C
                                                                         26
                                                                                28
                                                                                      30
Figure 2.  Comparison of the monthly water temperature and salinity in Santa Rosa Sound in 1959, the year of lowest average
         salinity in the 1951 through 1960 period.

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94
ENVIRONMENTAL REQUIREMENTS OF MARINE INVERTEBRATES
                    32

                    30

                    28
                  o
                 =^26

                  t~24

                  522
                  t/>

                    20

                    18


                    16
   DEC
            NOV
                                   OCT
        JAN
                       12    14    16    18     20     22     24    26
                                              TEMPERATURE, 0°C
                                                 28
                                                       30
                                                             32
                                                                  34
      Figure 3. Comparison of the monthly water temperature and salinity in Santa Rosa Sound in 1954, the year of highest overage
              salinity end highest water temperature in the 1951 through 1960 period.
   There are several possible explanations  for this
changed pattern. It is typical of course for metabolic
activity to decline with older animals, and it might
be suggested that this combined with the demands of
summer  spawning  is  sufficient  reaseon.   In New
England waters, however,  growth and spawning are
not antagonistic in timing, nor is it likely a process
of aestivation,  as I once assumed, at our summer
temperature of about 90°F, since a similar decrease
in mid-summer growth is reported by Medcof (1961)
in the Canadian oyster at summer temperatures in the
neighborhood of 75 °F.  The  important point  here is
that  with  the  rapid  growth of  shell  in  southern
oysters  it  is  frequently difficult to age an animal.
Growth observations involving experimental animals
of the same size but of different year  classes may
produce paradoxical results.

   There are other features  of the growth response
in mollusks that  make this  at times an ambiguous
criterion of the environment, to say the least, unless
considerable background data are available.  I should
like  to cite some examples that bear on this point.

   The  effect of temperature on growth rates  may be
seen in some Rhode Island hard clamsfM.  mercenaria)
sent  to  our  laboratory  in  the  fall.   The effect is
dramatically shown  in these clams by the white shell
(Figure 4), which represents their  growth when placed
in a clean sand bottom after  having been grown in a
muddy area.  Approximately 75 percent of this new
shell  was  formed during the months of December
and January, when had the clams remained in their
native habitat they would have been hibernating.  This
is the simplest and most obvious growth-rate response
on  the part of the  mollusk  to  one  environmental
factor, temperature.

   A less obvious response is shown in the hard clams
depicted in  Figure 5.  These clams, produced in the
Bureau  of  Commercial  Fisheries Biological Lab-
oratory  at  Milford, Connecticut,  by artificial prop-
agation,  were  sent  to Florida when approximately
one-quarter inch in diameter.  They were reasonably


                                    Figure 4.  Hard clams, Mercenaria (Venus) mercenaria, transplated
                                             from Rhode Island to Florida in the fall were approxi-
                                             mately one-half inch in diameter.  They doubled in size
                                             in the winter  months in Santa Rosa Sound when they
                                             would normally have been in hibernation.

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                        Reaction of Estuarine Mollusks to Some Environmental Factors
                                                                                                       95
                                             A>;
      r       ~   "':i-'"   '""  "   TV.-'."-
 Figure 5. Hard clams,  M. mercenaria,  derived from a laboratory
        culture and of uniform size when planted.  Individuals,
        from top to  bottom, represent smallest, median,  and
        largest clams recovered from the two locations at  end
        of second year.
uniform  in size, but were sorted into two lots whose
average  lengths were  nearly  identical.  These two
lots were planted in protected boxes on either side
of the laboratory  island and maintained for 2 years.
From the biologist's point of view, the two stations
were as nearly similar as one could select in the
natural environment.

   At the end of the 2  years, although mortality had
been  negligible in the two groups, there were  very
significant differences in the size range and average
size in the two groups.  The  larger-size group (east)
produced 24 percent greater volume of meats when
the clams were harvested.

   The boxes  containing these clams  were suspended
from the docks at midwater and covered with hardware
cloth.  As such,  they offered  a protected  niche for
a  variety of  other  sand-dwelling forms.  Morton's
cockle, Laevigatum  mortoni, was conspicuous at all
times. This small clam with inflated valves and usually
less than an  inch  in length is of no commercial im-
portance.  At the time the boxes were examined
finally, there  were ten times as many cockles in the
box  at the east station and they were on the average
50 percent larger than those in the west box. Similar
differences have been observed in the growth and set
of oysters  at  these two  stations.   A hydrographic
survey  of these two  stations  by  the Oceanographic
Department of A & M College of Texas failed to uncover
any  physical  feature  in the  environment that  would
account for these differences in the growth of these
mollusks.

   Finally, on the question of  growth, it is possible
to demonstrate a  differential  response due  to an
entirely  different and  in  this  case  an explainable
cause.   Some  years  ago, we  obtained a  supply of
seed  hard clams  derived from reciprocal crosses
of pairs  of the  northern  and  sourthern variety of
quahog.   These seed  clams  were in the size  range
from 1/16 to  l/8th  inch when  planted and we  main-
tained them successfully for  more than 4 years,  side
by side in protected boxes hung from the laboratory
dock.  At the end of that time, the stock of pure M.
mercenaria was on the average 50  percent longer,
and  the  meat yield of shucked clams  was nearly
double that of the hybrid stock.  Whether this  was
actually a hybrid cross has been questioned, but  this
is immaterial to the point that they were of controlled
parentage.  Each group of clams had been derived
from separate  gene pools and  had  shown distinctly
different growth characteristics in identical biological
environments.

   Knowing these different growth responses exist, we
are  impressed  with the necessity  of knowing  the
complete background of test animals before hazarding
a guess as to the reasons for their observed growth
rates in  any  particular situation.   We must know
the  age  of the animal, we  must know its genetic
background, and we must be assured of the similarity
of our test sites before we can suggest that this or
that  is truly a response to an environmental factor.

                REPRODUCTION

   The unreliability of random growth-studies  for
assaying the suitability of the environment to mollusks
led us to consider the possibility of using the seasonal
gonad  cycle  in oysters as  an index of well-being.
Small populations of oysters were kept in protected
trays, specimens were sacrificed at monthly intervals,
and  the  activity of the gonads was  evaluated on an
arbitrary  arithmetic  scale  (Butler,  1949). We  were
fortunate  in having data on the gonad  cycle of oysters
growing in Chesapeaka Bay,  as well as having some
Chesapeaka Bay oysters that had been transplanted to
Florida,  for  comparison with the native oyster. In
general,  the gonad cycle was the same for the three
groups with the exception of the timing (Butler, 1955).
The  Chesapeake Bay oysters, after 1 year of adjustment
in Florida waters, started  spawning  at a temperature
level 5°C  above that of their parent  stock,  and
reached  a stage of mass spawning  also  at  a 5°C
higher temperature level. In addition, their spawning
period was extended from the usual 3-1/2 to 5 months.
Their reproductive activity was indistinguishable from
the native Florida  oysters.  Figure  6 compares the
timing and level of  gonad  activity in the two  stocks
of oysters at each location.

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 96
ENVIRONMENTAL REQUIREMENTS OF MAIRINE INVERTEBRATES
 TEMP
  0°C
        30
        25
        20
GONAD

ACTIVITY
                             I   I   I  I
           C. at P.I	1_
      I  I   I   I
                                         I
           APRIL]  MAY | JUNE | JULY | AUG |  SEPT |  OCT
Figure 6.  Comparison  of reproductive  cycle in  two  stocks of
         oysters,  in which spawning was arbitrarily considered
         as the maximum level of activity: Chesapeake oysters
         (C) growing in Chesapeake Bay; Chesapeake oysters
         (C at P) after growing for two years in Santa  Rosa
         Sound; and (P) Florida native oysters growing in  Santa
         Rosa Sound.  The horizontal bars indicate the duration
         of the spawning periods while the vertical bars, ranging
         from  about 20 to 90 percent,  indicate the  number of
         spawners in each sample.

   These results suggest that the oyster's reproductive
activity is regulated primarily by changing temperature
levels rather than a hereditary response to a specific
temperature threshold.  Examination of our decade
of spatfall records in Santa Rosa Sound indicates that
spawning is unitiated  following  a 5°C temperature
rise  within  a   30-day  period.  The actual  onset of
spawning has occurred at temperatures ranging from
18  to 27°C, and varies  in time from early March
to  mid-May.   In this area  at  least,  the  fact that
oyster spawning has been initiated tells you essentially
nothing about the time of the year  or the temperature
of the water.

   It  might be  expected that if northern oysters ac-
commodate to  the water temperature regimen in the
south the reverse might be true. There are numerous
citations, however, of the failure of southern animals
to spawn when transplanted to more northern latitudes.
It is important to note that the response of the oysters
here  is apparently not to temperature per se but to
a relative  change in temperature.  This may account
for their failure to spawn in northern waters,  although
this failure  is usually explained on the basis  of a
particular  threshold value, and inferentially, physio-
logical speciation.

   Variations in the onset of spatfall from year  to
year  have been mentioned  briefly.   The timing  of
the spatfall  and  the amount  of   successful set are
of  particular  concern  to  the  commercial oyster
grower.    They are also of interest to the biologist
in  considering  the  relationship  of species  success
and specific factors in the environment.   The study
of spatfall  has been a favorite tool because of the
relative  ease  in  obtaining  objective  data that are
susceptible to statistical analysis.

   At our laboratory, squires of cement-board off ering
100  square  centimeters of  surface  are  suspended
from the dock and changed at 7-day intervals (Figure
7).   The number of sedentary organisms per square
centimeter is then calculated by counting a varying
percentage of the surface depending  on the numbers
of organisms present.  It is of interest that in more
than a decade of such observations, we have always
had  at least one  macroscopic, sedentary animal on
the  plate  by  the end  of the week  (Butler, 1954).

   Presumably the amount of  spatfall on these plates
is one measure of the adult oyster's response to the
environment; while this is true, it is by no  means
the entire story.   I am not considering at this point
areas in which from  time to time the annual set is a
complete failure.  In Santa Rosa Sound, the annual set
is normally  so heavy as to be objectionable from the
commercial point of view. The density of the spatfall
is greatly influenced not only by the amount of spawn
produced by  the adults but also by events in the pelagic
life  of the larvae.  Their numbers may be affected
seriously by  sudden hydrographic changes, by disease,

                                     Figure 7.  Weighted  wooden  frame  supporting  four-inch  square
                                             cement-board plates used to collect natural oyster set.

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                        Reaction of Estuarine Mollusks to Some Environmental Factors
                                                 97
or  by the relative success of some predator.  For
these  and other reasons, the record of one  year of
spatfall in a particular environment may be of little
value.

   A  summary  of  a decade of records of spatfall in
Santa Rosa Sound is shown in Figure 8. A line graph
of the averaged  data  indicates a  not unpredictable
distribution of  the set thruout the summer months,
starting  and ending at low levels and with an early
summer peaking of the set. Examination of the records
for individual years, however, immediately reveals the
error in this picture.  The solid area in each year's
record indicates the period during which 50 percent
of the total set  for  the year was collected on the
plates.   This  period varied  in  length from 2 to 6
weeks and  more  importantly varied from  month to
month during  the summer,  seemingly at random.
There was  no  apparent  relationship between  the
timing and the  total set  in any particular year.  The
accumulated seasonal  set varied  from 13 to more
than  90  spat per  square  centimeter in the period
under consideration,  and in  other years,  has been
nearly double this amount.  Oyster and clam larvae
have  relatively  short  pelagic  lives, and Davis (1958)
has shown that  they are  far less tolerant than adults
to changing hydrographic conditions.  Consequently,
these spatfall data reflect the  effect of the environ-
ment  on  the larvae rather than on the mature  oyster.
   We  know  too,  from long  experience,  that  our
estimates  of  the total  weekly set can vary greatly
depending  on the skill of the technician in handling
the cultch  plates.  Variations in angle of plate, level
in the  water,  intensity  of  barnacle set and  other
factors have  predictable effects  on the successful
set of oysters on the plates.

   We have had  at least one clear demonstration of
the drastic effect that environmental factors may have
on the  intensity of set,  and the fact that they exert
their  influence on the larvae rather than on the adult.
On August 30, 1950, this area experienced a severe
tropical storm that  brought more than 7 inches of
rainfall  and  a  storm  tide of 5.5 feet.  Figure 9
graphically portrays  the change  in oyster  set on
artificial   cultch during the period of  this  storm,
and in adjacent years when no such storm occurred.
It  is  clear here that  the increase in set has been
entirely the result of larval survival  and not pro-
duction, since  the  increase was limited to the period
of larval life of the brood and occurred before a new
brood could have matured.

   Larvae of other sedentary forms as well as the total
plankton mass were similarly affected; table 2  shows
the relative  changes in some setting rates from the
period one week before the  storm to one week  after-
wards.
                                OYSTER SPATFALL, SANTA ROSA SOUND, FLORIDA
                         CUMULATIVE SET PER
                         YEAR PER em 2
                                                                                      ij 19S1  68,23
                                                                                   .._	 1959 68.72
                                                                                         I9SS 54,53
                                                                                         1957  92,42
                                                                                         1951  13,08
                        S10J5202S  EM01520ZS  SI0182025 51OI5202S  510152025  510152025  51CMS2025 S10ISZQ2S
                  MAR      APRIL-      MAY      JUNE     JULY      AUG     SEPT      OCT      HOV
                DURATION OF SPAWNING PERIOD IN WEEKS
                50% OF ANNUAL SPATFALL IN SHADED PERIOD
        Figure 8.  Seasonal and cyclic occurrence of oyster spat an artificial plates, which were changed at seven-day intervals.
                Data for 1953 incomplete and not included.

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98
                    ENVIRONMENTAL REQUIREMENTS OF MARINE INVERTEBRATES
                  Table 2. EFFECT OF STORM ON SETTING OF SEDENTARY ANIMALS


Barnacle
Oyster
Mussel
Bryozoa
Plankton
Ml/100 1
Incidence of organisms per cm^ per week
1 week before storm
0.3
1.1
0.1
0.1

0.9
1 week after storm
170.6
73.0
3.2
2.1

5.0

568x
67x
32x
21x

5x
   In 1953, this area  experienced another  tropical
storm, which was similar in all obvious factors except
that  the direction of the wind was different and there
was no accompanying storm tide. Following this storm
there was no observed increase in the set of plankton
organisms.

   In 1955 tropical storm occurred in the New England
area accompanied by high tides; Dr. Loosanoff (1955)
reported that more mature  oyster larvae were ob-
served  than  ever before  and the  set  was greater
than in the preceding 11 years.  The following year,
after two tropical storms in New England, he re-
ported that they had  experienced  the  longest setting
period in their 20 years of observations (Loosanoff,
1956).

   These observations  suggest that high waters had
leached from the neighboring marshlands some trace
elements or simple nutrients that has greatly enriched
the estuarine waters.   This enrichment caused in-
creased phytoplankton productivity and, in turn, re-
sulted  in  greater survival  of  the larval  broods.
                   NUTRITION
   The differential in molluscan growth and set onthe
east and west sides of the laboratory island in Santa
Rosa Sound has been a subject for our investigation
for some years. We have pursued such environmental
factors  as temperature, salinity, pH, nutrient salts,
dissolved copper, chlorophyll and other plankton pig-
ments, total plankton, turbidity, currents, and others,
without identifying any causal relationships. More than
a  decade ago, the existence in  this area of natural
substances in sea water responding to chemical tests
for  carbohydrates  was  reported by  Collier et  al.
(1950).  In the course of an extensive testing program,
they found  that concentration of this material was
positively  correlated with  the  pumping activity of
oysters; usually,  oysters did not pump during the
winter months when carbohydrate levels were less
than approximately 4 mg/1, nor in the summer at
levels much below 6 mg/1.   They postulated a causal
relationship (Collier et al., 1953).

   We re-examined this situation utilizing the same
basic techniques  and much  of the same equipment,
                    20
                 
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                      Reaction of Estuarine Mollusks to Some Environmental Factors
                                                                                                         99
in the hope this might explain our east-west station
differential (Butler et al., 1959).  We found carbo-
hydrate concentrations surprisingly low as compared
to data obtained earlier in the identical geographical
area; in fact, considerably lower than what has been
reported  as  minimal threshold values  for oyster
pumping activity.  Consequently, we undertook a series
of continuing observations to  re-examine the putative
relationship between carbohydrate concentration and
oyster pumping  activity.

   Oysters  were  individually confined by means of
a plastic box and rubber dam  (Figure 10) so that when
the box  was attached to the inside  of a  larger tank
the inhalent side  of  the  oyster  was exposed to the
common water supply, the  exhalent side was separated
and the water pumped by each oyster could be  meter ed
and recorded on a kymograph. Movement of the upper
shell  was transmitted to the kymograph by means of
a thread.  Experiments were set up so that  the activity
patterns of ten oysters were recorded simultaneously
and hourly samples of water from the common source
were taken for carbohydrate analysis.

   Pumping of water by the  oyster while not quanti-
tatively related to food intake is ordinarily a pre-
requisite  to feeding.  Included here under  the general
heading of nutrient are various observations onwater
pumping, shell movement and shell deposition.

   Figure 11 illustrates a section of a typical kymo-
graph  record of  the  simultaneous activity of three
oysters in the  same aquarium over a period  of about
3 hours.  The top line 'P' of oyster number 1  records
Figure 10.  Oyster attached  to  plastic frame with  rubber  dam
         separating inhalent (dorsal) from exhalent side.  This
         makes possible recording the amount of water pumped;
         thread attached to upper valve transmits  shell move-
         ment to kymograph.

the number  of times  the effluent water bucket was
tripped.  In this case, pumping appears to be relatively
uniform,  although the rate varies from about 30 to
50 units  per hour or the  equivalent of  8 to 12 liters
per  hour.  We  are not  interested here, however,
in the  exact  quantity of water pumped, but rather in
the regularity of  the pumping activity.   The second
line 'S' shows the typically irregular movement of the
right valve as the oyster pumps.  The vertical lines
         Figure 11. Kymograph record of water pumped (P) and shell movement (S) of three oysters in same aquarium showing
                  individual variations in response to common environment.

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100
ENVIRONMENTAL REQUIREMENTS OF MARINE INVERTEBRATES
indicate an amplitude of 2 to 3 mms in shell movement.
In this  period the oyster did not  close its valves
completely.

   The record of the second oyster obviously shows
a  quite different activity.  The T?' line indicates a
decreasing rate of activity for  the first hour and
finally a cessation of pumping.  The shell movement
line indicates a progressive series of snap closures;
each time the valves open  somewhat less, and finally,
just  before  2200, the oyster  closed  completely.

   The third  record shows a similar interruption in
pumping and shell  closure, but after an hour the oyster
opened abruptly and continued pumping at its 'normal'
rate.

   These  records  illustrate well  the  individuality
of oysters in responding  to factors in  a common
environment.   It is  apparent that at about 2000
hours  there  was  some external  factor, which  all
three detected but responded to in a different manner.

   Our observations in this experiment consisted of
searching  the kymograph  record for each 24-hour
period to  locate times in  which the oysters as a
group exhibited normal activity, followed by a pro-
gressive slowing down, and then a return to the normal
rate of pumping.  Only the water samples collected
during these  stages were analyzed for  carbohydrate
concentrations.    In  all,  70 occasions  were found
that  satisfied all of the requirements for our testing
conditions.  The results of these analyses are shown
in Table  3.  Carbohydrate  concentrations were de-
termined when the oyster was pumping at a normal or
regular rate, and  then  again an hour later when the
kymograph record showed that its pumping was slowing
down markedly.   The data of the initial  carbohydrate
concentrations were  arbitrarily  grouped into three
ranges.  At the lowest initial range of 0-0.9 mg/1 the
graph shows that of the 24occasionswhenthe pumping
rate decreased, the carbohydrate concentration de-
creased  10 times, stayed the  same 3 times, and in-
creased  11 times.   Data for  the  other  ranges are
similar and,  in  sum, out  of the 70 periods, changing
carbohydrate  concentrations were  correlated with
decreased pumping negatively 41 percent of the time,
positively 40 percent, and  showed no change 19 per cent
of the time.
        Table 3. CHANGES IN SEA-WATER
    'CARBOHYDRATE' CONCENTRATION WHEN
        OYSTERS WERE OBSERVED TO BE
     DECREASING THEIR PUMPING ACTIVITY
Initial concentration
of 'carbohydrate'
mg/liter
0.0 - 0.9
1.0 - 1.9
2.0 - 4.3
Direction of change and
number of observations
Decrease
10
16
2
Static
3
10
0
Increase
11
17
1
                                      The second  method we used to correlate oyster
                                   pumping activity with carbohydrate concentration was
                                   to  estimate the number of hours of the day when the
                                   oyster was actively pumping and compare this  with
                                   the level of carbohydrate in a composite sample of
                                   water for the 24-hour period.   The lengths of these
                                   periods were  tabulated  on a percentage basis, and
                                   plotted against  the carbohydrate  levels (Figure  12).

                                      Since  in our area oysters may show a differential
                                   pumping  activity that is apparently correlated  with
                                   temperature, the data are grouped at two different
                                   temperature levels.  In the range of 10 to 20°C,  i.e.,
                                   from  January through March, daily pumping activity
                                   occupied from  65 to 100 percent of the time.  Carbo-
                                   hydrate  concentrations  were  all  below 4  mg/1.
                                   Records of many periods of almost continuous activity
                                   were obtained when carbohydrate concentrations were
                                   between 0.0 to 0.9 mg/1.  A decade earlier, almost no
                                   pumping activity was observed at carbohydrate levels
                                   below 4 mg/1 in this temperature range.
                                      At  temperatures between 20 and 30°C, market size
                                   oysters may be expected to show less pumping activity;
                                   in  this  experiment activity  ranged from 25 to 95
                                   percent.  With  minor exceptions, all of this pumping
                                   took place at  carbohydrate  levels below 2.0 mg/1.
                                   Collier found at these temperatures it was necessary
                                   to  have a carbohydrate concentration of approximately
                                   6  mg/1  before pumping was initiated.  Figure 12
                                   indicates little  if any correlation between increased
                                   pumping activity and increased levels of carbohydrate
                                   at  either temperature  range; nor does there appear
                                   to  be  any  minimal  threshold below  which oysters
                                   were inactive.
                                      I am  reporting this material  in some detail be-
                                   cause  it is important to note that what at one time
                                   appeared  to  be  a  clear-cut relationship between
                                   oyster behavior and  a particular parameter of the
                                   environment is  now open to a different interpretation.
                                   This  is  not to suggest that in  the earlier work the
                                   activity of oysters was not correlated  with carbo-
                                   hydrate concentrations, but rather that at that  time
                                   oyster activity  and carbohydrates were  both related
                                   to  some other and still unknown environmental factor.

                                      Numerous workers  have noted the  characteristic
                                   shell  movements of oysters under varying internal
                                   and external environmental conditions. The spawning
                                   reaction  of ripe males, for example, is easily stimu-
                                   lated  by appropriate temperature changes and,  in
                                   turn, the reaction of ripe females to sperm suspension
                                   or to  temperature is clearly defined (Galtsoff, 1961).
                                   A  similar group response is illustrated in Figure 13,
                                   which excerpts  a 5-hour record of two mature oysters
                                   in  a common aquarium.   The shell movement lines
                                   indicate  a  series of snap closures  of the  shell at
                                   approximately hourly intervals. These partial closures
                                   occurred at the rate  of  about two a minute,  and had
                                   no effect on the pumping rate as seen by the regularity
                                   of  the pumping  record. This response has been noted
                                   on  numerous  occasions  and  we  at first thought it
                                   indicated spawning behavior.  Later, it was observed
                                   during the  winter  months and commonly a majority
                                   of  the animals in a  community aqaarium showed the
                                   reaction simultaneously.  The reason for this reaction
                                   is  unknown but it  typifies the  oysters' sensitivity
                                   to  apparently subtle factors.

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                     Reaction of Estuarine Mollusks to Some Environmental Factors
                                                                                             101
              u
              o

              S
           u

           o
           3
           Q_

              u
              o
100




 80




 60




 40




 20









100




 80




 60




 40




 20
                                     1234


                                                CARBOHYDRATE, mg/l



Figure 12. Normal pumping activity, i.e., percent of time oyster was open and pumping, compared to concentration of natural

          'carbohydrate' at two temperature ranges.  Each dot represents the level of activity of one oyster for one day at the

          indicated temperature and level of 'carbohydrate'.
              OYSTiR
              OYSTER 2
                        HOUR
Figure 13.  Kymograph record of shell movement (S) and pumping rate (P) of two oysters  in a common aquarium. The (S) lines

           indicate their simultaneous response to some  external factor at approximately hourly intervals.

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102
                    ENVIRONMENTAL REQUIREMENTS OF MARINE INVERTEBRATES
   The  recording of shell movement and  pumping
activity of oysters provides a convenient tool for the
evaluation of pollutants  added experimentally to the
environment.   In some  preliminary work, we  found
many of the common argricultural pesticides had a
marked deleterious action on oyster sat concentrations
ranging from 0.01 to  1.0 ppm in running sea water
(Butler et al», 1960).  The number of hours per day
that the oyster was open and pumping steadily de-
creased after  a week  of  continuous  exposure to a
noxious  chemical.  For example,  after 5 weeks of
continuous  exposure  to Dieldrin  at 0.1  ppm the
daily activity of exposed oysters was only  half that
of  controls (Figure 14).  The graph  shows clearly,
too, that  after  removal to clean water there was a
fairly rapid recovery.

   This  reaction  of the oyster to its environment
is clear-cut and provides useful data.  The technique,
however,  is tedious and time consuming.  It is more
expedient under the same experimental conditions,
simply  to measure the rate of deposition of new  shell
in juvenile  oysters. In  Figure 14, these data are in-
dicated as percent growth.  It  is apparent in the graph
that there  is an immediate  decrease in this  shell
deposition in the experimental oysters, whereas de-
creases in percent pumping activity of mature oysters
were not apparent  until  after the  second week of
expousre  to the pollutant.  The recovery in the rate
shell deposition follows the same pattern as the return
to normal pumping  activity.  It is of interest to note
the  simultaneous  response  in activity  and   shell
deposition in both experimental and control oysters
to the relatively small temperature fluctuation during
the terminal 3 weeks.
   Linear growth  of the oyster does not proceed at a
uniform rate under uniform conditions.  There is an
initial increase in the  terminal deposition of shell
followed by a period during which  this new  shell is
thickened  by internal deposits.   During this stage
there may be no increase in length.  In order to avoid
misinterpretation  of these length increases, the shell
of the oyster is filed until all new or thin shell has
been  removed; the oyster meats then occupy all of
the available space. Under these conditions, the oyster
has no alternative in  growing except to deposit new
shell at the posterior end.  Figure 15  shows one of
these oysters with the shell newly filed, and deposits
of new shell at the end of 2 and 7 days. Under average
conditions, shell deposits are made at the rate of ap-
proximately 4 millimeters per week in control oysters.
The average amount of new shell deposited by oysters
under  comparable  conditions is uniform and  statis-
tically valid even for small groups.  We are finding
it a most useful criterion for evaluating the relative
toxicity of a large  series  of pesticide  chemicals
and determining at what concentrations these chemicals
become physiologically  unacceptable to the oyster.

   It is apparent from these data on the toxic quality
of agricultural pesticides that mollusks exhibit at least
three types of  reactions.   In the  first type, as the
concentration  of  the  pollutant  is  decreased, by  a
factor of ten for example, the rate of shell deposition
gradually increases to that of the controls. This may
be noted with such chemicals as endrin, aldrin  and
heptachlor.

   In the  second  type,  a given concentration  may
cause  a  marked  decrease in shell  deposition, yet
                      w  13

                      ^  12

                      u  11
                      a.
                        80



                        60



                        40

                         8
                            Ik
                           LEXJ=OSURE_

                        Weeks  1
                                                           1 RECOVERY-
     Figure 14.  Pumping activity of mature oysters in running sea water exposed to a Dieldrim concentration of 0.1 ppm for 5 weeks,
              and for the succeeding 3 weeks in unpolluted water. The growth rote of juvenile oysters held in the same tanks (E)
              is compared to control juveniles (C).

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                       Reaction of Estuarine Mollusks to Some Environmental Factors
                                               103
          Figure 15. Shell deposition on  l-'/2-in. oysters. Control on left; after 2 days (middle); and after 7 days (right).
dilution  by a  factor  of  ten renders  it  apparently
harmless.  It seems that in a wide variety of pesticides,
including dieldrin, Kepone, and parathion, there is a
fairly sharp threshold  level of toxicity.

   In this third type,  our data are  still incomplete.
Small hard clams are being exposed over relatively
long periods of time  to four chemical pollutants at
concentrations  from 100 to 1000 times more dilute
than levels found irritating to small oysters. In the
first  3 months, all  groups  grew as  well as controls
and showed similar activity and mortalities. In the
fourth month, clams exposed to  one part per billion
of  DDT  have   experienced a  sudden mortality of
approximately  30 percent.   They are sluggish when
uncovered  and fail  to bury themselves in the  sand.
It is possible in this case, that there has been either
an accumulation of the toxicant to lethal levels within
the clam or else a  loss of resistance on the part of
the clam.   In either case it indicates the possibility
of a build-up, over long periods, of low concentrations
of pollutants in an estuary until they finally become
disastrous  to molluscan populations.

                    CONCLUSION

   A great  deal of work remains to be done in identify-
ing  the  reactions  of mollusks  to   specific natural
factors in the environment and to man-made pollutants.
It is  obvious  that  variations in environmental
parameters may become limiting factors, as they ap-
proach extremes.  Thus, high or low  salinity controls
the expansion of oyster populations  at either end of
the estuary.   Similarly, low temperatures suppress
spawning  the  population  expansion of the  eastern
oyster when transplanted to the Pacific coast.

   Over a broad intermediate range of environmental
conditions, however,  the survival of molluscan popu-
lations is a result of highly complex and inter-related
attitudes toward individual factors. Apparently simple
responses,  such as  growth rates, may  be greatly
influenced by age,  or heredity, or nutrient salts and
vitamins  naturally  present in the  environment  in
only trace amounts.

   Although  acute  toxic levels of natural and  man-
made pollutants are quite  simple  to demonstrate, the
effects  of  low levels of  toxicants are  much  more
obscure,  and  disasterous changes in productivity
levels might occur without significant mortality. Our
ability to delineate  the individual factors  that are
deleterious to estuarine forms will determine in large
measure our success in preserving this  part of the
marine environment, which is so sensitive to pol-
lution.   Only by  understanding the role  of both
beneficial and harmful  factors  will  we  be able to
reach maximum  utilization of our estuaries for both
biological and industrial purposes.

                ACKNOWLEDGEMENT

   It  is a privilege to acknowledge the assistance and
cooperation  of the  entire  laboratory staff whose
efforts during the past decade have made this summarj
possible.

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 104
ENVIRONMENTAL REQUIREMENTS OF MARINE INVERTEBRATES
                                              REFERENCES
Butler, Philip A., 1949.  Gametogenesis in the oyster
under  conditions of depressed salinity.  Biol. Bull.,
96: 263-269.

Butler, Philip A.,  1952.  Seasonal growth of oysters
(C, virginica) in Florida. Proc. Natl. Shelfish. Assoc.,
43: 188-191.

Butler, Philip A.,  1954.  Selective setting of oyster
larvae  on artificial  cultch.   Proc.  Natl.  Shelfish.
Assoc., 45: 95-105.

Butler, Philip A., 1955.  Reproductive cycle  in native
and  transplanted oysters.   Proc.  Natl.  Shellfish.
Assoc., 46: 75.

Butler, Philip  A., and  Alfred J. Wilson,  Jr.  1959.
Relation  of oyster  pumping  to the  carbohydrate
concentration of sea water.   Convention  Address,
Natl. Shellfish. Assoc.

Butler, Philip  A., Alfred  J.  Wilson,  Jr., and Alan
J.  Rick.   1960.    Effect of pesticides on  oysters.
Proc. Natl. Shellfish, Assoc., 51: 23-32.
                                   Collier, Albert, Sammy M. Ray, and Wayne Magnitzky.
                                   1950.   A preliminary note on  naturally occurring
                                   organic substances in sea water  affecting the feeding
                                   of oysters.  Science, 111: 151-152.

                                   Collier,  Albert,  S.M.  Ray, A.M. Magnitzky and Joe
                                   O. Bell.  1953. Effect  of dissolved organic substances
                                   on oysters.  Fish. Bull. USFWS, 54: 167-185.

                                   Davis, H. C.  1958.  Survival and growth of clam and
                                   oyster  larvae  at  different salinities.  Biol. Bull.,
                                   114: 296-307.

                                   Galtsoff, Paul S., 1961.  Physiology of reproduction
                                   in molluscs. Am. Zool., 1: 273-289.

                                   Loosanoff, V.L., 1955.  Milford  Laboratory Bulletin
                                   No. 10. 2pp. mimeo,

                                   Loosanoff, V. L.,  1956. Milford Laboratory Bulletin
                                   No,, 11. 4 pp. mimeo.

                                   Medcof, J.C.,  1961. Oyster farming in the Maritimes.
                                   Fisheries Res. Brd. Canada, Bull. No. 131, pp. 1-158.
                                               DISCUSSION
   The discussion following the formal presentations
immediately  centered upon our lack of basic knowl-
edge  of the  effects  of pollution  on the estuarine
environment.    Considerable emphasis was placed
upon  the  need for  an investigator to know his ex-
perimental animals thoroughly before attempting to
interpret  the results.   The  work reported to this
time  has  demonstrated the great  diversity of re-
sponses  that may be expected between  or among
animal  groups and life history stages.  Delayed or
indirect  effects  often turn  out to be the most im-
portant feature uncovered by  a given investigation.
The  subtlety  of  such responses brought up the ob-
jection  to  "kill - no kill"  as parameters in toxico-
logical  research.    There was general agreement
that  we  should work on  the  more subtle, physio-
logical  effects  of sub-lethal  toxicity.  Comments
from the  floor   supported  the participants' views
in pointing  out the  need  for  basic  studies on en-
vironmental requirements of larval development since
this   is often the  most sensitive  stage in  the life
history of estuarine animals.

   Dr. Carraker concluded the session with a sum-
mary  of  the presentations  and  suggested  that, in
                                    selecting or  determining the  range of parameters
                                    which are suitable for the environment in a particular
                                    estuary  or embayment,  the following should be at-
                                    tempted:


                                       1) A  systematic  study  of  the dominant  species
                                         present,  so  that we  have a  good taxonomic
                                         base upon which to  build.


                                       2) A  field, ecological-life  history and horizontal
                                         distribution  and  density  study of the  major
                                         species.


                                       3) Rear animals  in  the  laboratory under con-
                                         trolled  conditions,  and subject them to changes
                                         in  these parameters,  one by one,  then in
                                         combination  and then in fluctuation, to  try to
                                         simulate  the  complex which exists in the en-
                                         vironment.

                                       4) Lastly,  to bring to our aid,  mathematics and
                                         computers to help make a proper interpreta-
                                         tion of these conditions.

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               ENVIRONMENTAL REQUIREMENTS OF AQUATIC INSECTS
                                        T. T. Macan, * Chairman
                         ENVIRONMENTAL REQUIREMENTS OF PLECOPTERA
                                           Arden R. Gaufin^
                  INTRODUCTION

   Stoneflies constitute a relatively  small order of
aquatic insects,  with a world fauna of  around 1,200
species.    Approximately 400  of these have  been
described for North America.  The order is divided
into two suborders:   the Filipalpia, in  which the
nymphs and adults  of many genera  are primarily
herbivorous; and the Setipalpia, in which the nymphs
are usually carnivores and the adults in  most genera
do not feed.   The world fauna includes nine families
(Ricker,  1952), six of which occur in North America.

   Stoneflies require moving water for the development
of the nymphs, and in most areas the immature stages
are passed in streams.  In some northern regions
such as Sweden the early life history stages of some
species have  been  reported  to occur in cold lakes
where  the  shore  areas are  composed of gravel.
(Brinck, 1949).

   Although Stoneflies constitute one of  the  smaller
orders of insects, they are nevertheless one of the
most  important groups found in many streams.  In
mountain streams, they are one of the principal sources
of food for  trout.  Adult members of the genus Brach-
yptera are reported to feed on  the tender buds of
soft fruit crops in the Pacific Northwest (Newcomer,
1918).   Because of their preference for clean, well-
aerated water, Stoneflies are becoming  increasingly
important to limnologists as indicators of clean water
conditions in pollutional surveys.

          REVIEW OF THE LITERATURE

   Practically all of the studies to date  on the North
American stoneflies have dealt with their taxonomy and
morphology.  The early work of Claassen in New York
and Prison in Illinois revealed the diversity of  species
found in eastern and midwestern United States.  More
recently the  studies of Ricker in Indiana and Canada,
Jewett in the  Pacific Northwest, Hansen in  the New
England States, and Gaufin in the Inter mountain Region
have  advanced our knowledge of stoneflies in those
sections of North America.  Despite the work that
has been done to date, the nymphs of over 50 percent
of our  North American  species  have not yet been
described.
species.
This is  particularly  true of western
   Research conducted by Hynes (1941), Aubert (1946),
and Brinck (1949) in Europe indicates that European
stoneflies differ perhaps more in their ecology than
they do taxonomically or morphologically.   In view
of this finding, detailed information as to  the  habitat
requirements  and  physiological  differences  of  the
various species  may be essential to stonefly taxo-
nomists if they  are to separate the many  yet uniden-
tified forms.

   Most of the ecological data that have been published
concerning  North  American stoneflies  consist of
general statements  as to habitat preferences.  Prison
(1935),  for  example,  stated that certain species in
Illinois were found only in small streams, while others
were  found only in large streams.  He also indicated
that the type of bottom is an important factor govern-
ing the  concentrations of different species of stone-
fly nymphs.

   Hynes (1941) mentioned five major factors as con-
trolling the  distribution of stoneflies in  England,
namely, the  movement  of the water, altitude, sub-
stratum, drought, and the possibilities of colonization.
Brinck (1949) considered the following factors as being
most  important in  determining  the distribution of
Swedish  stoneflies: Movement  of the water, sub-
stratum, temperature, the amount of certain gases and
compounds in the  water, and the presence  of food.
He determined the  water velocity, temperature, dis-
solved oxygen content, and pH in a number of streams
and showed how these factors  influenced the distri-
bution of certain species of stoneflies. He also classi-
fied various stonefly habitats based on different per-
ceptible environmental conditions.

                   DISCUSSION

CLASSIFICATION OF STONEFLY HABITATS

   Several authors, in examining the ecological distri-
bution of  stoneflies, have proposed classifications of
streams and rivers based on their more  obvious
physical characteristics (Hynes,  1941; Ricker, 1943;
 * Naturalist, Freshwater Biological Association, Westmorland, England.

 "|" Department of Zoology and Entomology, University of Utah, Salt Lake City, Utah.


                                                   105

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 106
ENVIRONMENTAL REQUIREMENTS OF AQUATIC INSECTS
and Brinck, 1949).  Because the actual effect of many
factors controlling  the  distribution  of  stoneflies  is
unknown,  a detailed  classification of stonefly habitats
is impossible,  but the classification of Hynes is very
useful in pointing out the habitat preferences of stone-
flies  in  England.   All  of the habitats cited can be
found  also  in  various sections of North America.

   Hynes  classified stonefly habitats into two primary
divisions, running water and still water, with a number
of subdivisions for each.  The running-water habitats
include trickles; small stony streams such as are
found  in  hilly  and  mountainous regions, which vary
from 1 to 5 yards in width; stony rivers, also typical
of hilly and mountainous regions, which  range in size
from  10  to  30 or  more  yards  wide;  and sluggish
rivers.  He  subdivided still-water habitats into two
categories, the stony shores of lakes  and the sub-
merged parts of emergent vegetation of mountain pools.

   Brinck (1949) in  his  classification of  Swedish
streams added the concepts of eutrophication and temp-
erature differences as brought about by differences
in latitude and  altitude. Hora (1930) discussed in some
detail the  microhabitats  in rapidly running water,
which further emphasized  the  importance of  physio-
graphic differences in determining the distribution of
stoneflies.  The moss found on the top of large stones
and  boulders,  the undersides of  large  boulders and
loose stones, the detritus and sand between the stones
and  gravel,  and pockets of dead leaves  and grass all
provide  habitats  preferred  by  certain  species  of
stoneflies.   Moss   and  algae, for example,  provide
very suitable conditions for such stoneflies as Aero-
neuria pacified and Isoperla fulva in stony streams of
the Rocky Mountains. The undersides of large boulders
and  loose stones provide  the  habitat in which larger
species  such as Claassenia arctica and Pteronarcys
californica  usually  live  and characterize  larger
streams and rivers.  Pockets of dead leaves and grass
provide  habitats for such species as Nemoura cine -
tipes  and Capnia gracilaria  in small stony streams
and  trickles of the mountainous western United States.
 FACTORS CONTROLLING THE  DISTRIBUTION OF
 STONEFLIES
   While  a classification of stonefly habitats into the
 categories  given is very  useful in explaining the
 general  distribution of stoneflies,  detailed studies
 of the factors controlling their distribution are nec-
 essary in order to explain their presence or absence
 in specific habitats.

   Schoenemund (1924 and 1925b) stated that industrial
 pollution  of bodies of  fresh water exterminates the
 stonefly fauna,  and indicated that the occurrence of
 some  species in certain bodies of water is influenced
 by the oxygen content, the substratum, and the rate of
 flow of water.  Several authors in Europe and Claassen
 and  Frison in the  United States described in general
 terms the  habitats  of  various species and genera,
 but the first real attempt to define factors controlling
 distribution  of  stonefly nymphs was made by Hynes
 within the Lake District in England in 1941.
                                  In "The Taxonomy  and Ecology of the Nymphs of
                               British Plecoptera"  he  lists  five major factors  as
                               controlling the distribution of stonefly nymphs:

                                  (1) The movement of the water;
                                  (2) the  altitude, which  is  probably a function of
                                      temperature;
                                  (3) the  substratum, which  is  to a certain extent
                                      controlled  by  the movement  of  the  water;
                                  (4) drought and its relation to the length of nymphal
                                      life  of the species and the emergence period of
                                      the adults;
                                  (5) the  proximity  of habitats  in which stoneflies
                                      are abundant; this factor he refers to as colon-
                                      ization.

                                  In addition to these factors Brinck (1949), in his
                               comprehensive "Studies  on Swedish Stoneflies,"  con-
                               siders of primary importance such factors as water
                               temperature, the  amount of certain gases and com-
                               pounds in the water,  and the  presence  of food.  The
                               author has found that all of these factors are also  very
                               important in determining the distribution of stoneflies
                               in streams of the Intermountain Area of western United
                               States, but a  factor  of  equal importance is man's
                               activities.  In the United States, pollution, construction
                               of reservoirs, dredging,  and water diversion perhaps
                               influence the distribution of stoneflies more than all
                               other factors combined.

                                  Each of  these  factors is  discussed separately in
                               the  remaining portion of this paper.  In addition, the
                               results of experimental laboratory studies conducted in
                               the  last  4   years  by the author  and  his graduate
                               students  are  briefly considered where applicable.

                               WATER MOVEMENT

                                  The movement  of water  is perhaps the  most
                               important factor controlling the distribution of stonefly
                               nymphs  in  that it controls the oxygen  supply of the
                               water and to a certain extent the temperature, sub-
                               stratum, and food.   Stoneflies are very rarely found
                               in   stagnant  water  and  thus are  confined  almost
                               entirely to  moving streams or wave-swept shores.

                                  The oxygen content of the water during nymphal
                               development is an important factor in the distribution
                               of stoneflies.  Under normal  conditions  in almost all
                               streams or lakes where stoneflies occur the water is
                               saturated with oxygen. Certain species, however, such
                               as Nemoura cinerea  and Taeniopteryx nebulosa have
                               been reported by Brinck (1949) as being  present in
                               sluggish streams and rivers  in Sweden in which the
                               oxygen concentration dropped to 42 percent saturation.
                               The author  also encountered two species of stoneflies
                               in streams in Ohio living under similar  conditions of
                               oxygen reduction.  Taeniopteryx maura was collected
                               in large numbers from the Great Miami River above
                               Dayton,  Ohio, in  sections of the stream where the
                               dissolved-oxygen  concentration dropped to 4 ppm at
                               night. In this connection,  an interesting but unexplained
                               phenomenon was discovered involving a number of the
                               nymphs.    Most  of  the  nymphs taken  in the  most
                               stagnant sections of the stream where little movement
                               occurred possessed protruding anal gills. In a species

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                                Environmental Requirements of Plecoptera
                                               107
in which no such gills are supposed to occur this was
indeed  surprising.  It is surmised that  the popula-
tions with anal gills may have been better adapted to
obtain oxygen than normal specimens of this species.
This  supposition is  partly substantiated by our find-
ing  another  species,  Perlinella  drymo,  in  large
numbers  in a quite unusual and unexpected habitat.
This species is comparatively rare and to the author's
knowledge has been collected only in limited numbers
from riffles in fast-flowing streams of eastern North
America.  A  considerable number of specimens was
taken from very slow-moving  water from beneath
undercut, grass-covered banks  from Indian  Creek
near  Miamitown,  Ohio.  They were found in associa-
tion  with burrowing mayflies,  Hexagenia sp., and
damsel fly  nymphs, Agrion sp.  and Argia sp.  The
thoracic gills  of this species of stonefly are very con-
spicuous  and are perhaps longer and more copious
than  in  any other species  of  North American Ple-
coptera,

   Pollution  with organic wastes will often cause a
considerable deficiency of oxygen in streams. Brinck
(1949) reported that polluted sections of  streams  in
Sweden  with  an  oxygen content below  40 percent
saturation had  an  insignificant stonefly  fauna or
none. This may have been due, however,  not only  to
the lowered oxygen  content but also to the poisonous
substances  such  as  hydrogen  sulfide produced by
the breaking down of the sewage. In fact, laboratory
studies being conducted by the author cast some doubt
on the supposedly high oxygen requirements of stone-
flies.  Two species, Acroneuria pacifica, andPter-
onarcys californica; have been maintained in water
with  an oxygen  concentration as  low as 1 ppm for
7  days  at  temperatures  of 50°  to 51°  F with no
mortality occurring.    One  nymph  of  Acroneuria
pacifica  exposed to  this  low  concentration  later
emerged  as an adult when it was restored to normal
conditions.

   In addition to its role in oxygenation of the water,
water movement is  important in several  other ways.
In  slow-moving  streams, emergent  vegetation can
develop,  which provides a  habitat  in which  some
species of Nemoura   can live.  Fast-flowing water  is
generally without rooted vegetation, and often de-
posited dead leaves and detritus are lacking. Species
of stoneflies  dependent  on these materials for food
are thus  eliminated from streams where the current
may be  strong. On the other hand the slender nymphs
of such genera as Leuctra  and Alloperla are able  to
live  in  rapid  currents because they are able to work
their way down among the stones and gravel and find
detritus  that has been deposited there. Omnivorous
species such as Isoperla fulva, isoperla patricia, and
Isoperla mormona are very little  affected by strong
currents, and  thrive in fast-moving streams because
of the algae  that grow under such conditions.

ALTITUDE AND TEMPERATURE

   Extensive  collections of  stoneflies taken  from
streams in  the  Intermountain  Area  of the United
States during  the  last 15 years  at altitudes ranging
from 3,000  to 12,000  feet  clearly indicate a dis-
tributional pattern that correlates closely with alti-
 tude.  Because the effect of altitude is primarily one
 of  temperature, these two  factors  are considered
 together.  The  distribution of stoneflies in the Provo
 River,  Utah,  a stream that has  been intensively
 studied  by  the author since 1946, illustrates very
 well  the effects of altitude and temperature  on the
 species  present.  The river is  a typical, swift-flow-
 ing, well-aerated mountain  stream.  It has its origin
 in the high Uinta Mountains of northeastern Utah and
 runs  southwesterly  for  72  miles to its  outlet  at
 Utah Lake.  The upper section of the river is charac-
 terized  in  many places  by falls and cascades, but
 midway  in its course this turbulence is checked by
 the presence of Deer Creek Reservoir, a storage
 basin 8  miles long.  As the river enters Utah Valley
 the  rate of flow is  slowed markedly and  the water
 temperature  is notably  higher  than in the  upper
 portions of the stream.  The river originates at an
 altitude  of  approximately 10,000  feet  and empties
 into Utah Lake at an altitude of 4,400 feet.

   Six species of Alloperla have been collected from
 the  river,  but  none  at an altitude below 5,300 feet.
 Two  species, Alloperla borealis and Alloperla pin-
 tada, were taken only at  altitudes above 5,900 feet
 and Vtaperla  sopladora only above 6,400 feet.  On the
 other hand,  Isoperla mormona and Pteronarcys calif -
 arnica were found  only at altitudes below 5,900 feet,
 but closely related species, Isoperla fulva andPtero-
 narcella badia,  were found throughout the  river.  In
 a similar study being conducted on the Colorado River
 only two species of Isoperla have been  collected  in
 the lower section below 4,000 feet, whereas various
 species of Alloperla, Leuctra, and Capnia occur above
 10,000 feet. In the lower, turbid Colorado near Moab,
 Utah, the water temperature often exceeds 70°F  in
 the summer.  In the upper Colorado and its tributaries,
 water temperatures rarely exceed 50°F. The extreme
 turbidity of the lower Colorado, however, undoubtedly
 is more restrictive to stoneflies than the altitude or
 temperatures are.

 THE SUBSTRATUM

   The  substratum of both lakes and streams is very
 important to  stonefly  nymphs.  Pure  sandy bottoms
 or  a muddy bottom are very  seldom if ever inhabited
 by stoneflies.  On stable substrata consisting of large
 stones  and boulders, moss  and algae often develop
 on  tops  of the stones and  form a different micro-
 habitat  than is found among stones and loose gravel.
 Nymphs  adapted for clinging, as exemplifiedby several
 species  of Isoperla and Nemoura,  are typical of the
 former  habitat;  small slender species  belonging to the
 genera  Alloperla and  Leuctra  are more commonly
 found among  stones  and  loose  gravel in an unstable
 substratum.   Some carnivorous  forms such as Aero -
neuria pacifica  on the  other hand have long legs and
 strong  claws and occur  in either type of habitat.

 DROUGHT

   In the arid western United States, many streams
 dry up  during the summer and consequently support
 a very poor stonefly population or none at all.  Even
 in the  high  Rocky Mountains,  where the period of
 drought  is limited, intermittent streams support few
 stoneflies.  By  comparison, however, in the eastern

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108
ENVIRONMENTAL REQUIREMENTS OF AQUATIC INSECTS
and midwestern states, stoneflies can be found abun-
dantly  in many  streams that dry up regularly each
year.  The author encountered many small intermittent
streams in  Ohio that support an abundant and varied
stonefly  population  during  the  winter and  spring
months.  The adults of some common species emerge
in the winter  or spring and have a 1-year life  cycle.
Species occurring regularly in such streams are All-
ocapnia forbesi,  Allocapnia  viviparia, and Nemoura
nigritta.  The  nymphus of  these species are very
small or the eggs have not hatched when the streams
in which they occur are  dry, which enables these
forms  to withstand drought conditions.  The younger
nymphs work  their way down into the substratum to
available moisture  and thus  escape  disiccation.
Species  having  2-  or  3-year life  cycles, such as
Pteronorcys californica and Acroneuria pacifica cannot
avoid disiccation in a similar manner and are  conse-
quently unable to live in streams that dry up regularly.

   The lack of vegetative cover may  very well account
for the inability  of stonefly nymphs to last through the
hot summer months in dry, unshaded  streambeds in
the arid west.  The shade  afforded dry  streambeds
in the  eastern  states by  a forest canopy keeps the
bottom  moist  and prevents the eggs  or small nymphs
of the stoneflies from becoming completely desiccated.

COLONIZATION

   Most adult stoneflies stay close to the water in which
they lived as nymphs, hiding under stones or in nearby
vegetation.  A number  of  species arebrachypterous
such as Capnia columbiana and Isogenus parallela,and
very seldom can be found very far from the water's
edge.   Some  of the smaller Isoperla and Alloperla
can  fly  readily though slowly,  and will fly to other
bodies of water than that  from which they emerged.
Thus the adults may fly to a new habitat  and lay their
eggs, and the nymphs may grow and reach maturity,
and colonize  a  new area. While many of the smaller
species of stoneflies undoubtedly increase their distri-
bution in this  manner, one of the primary  factors
limiting the distribution of many of the larger species
is their relatively poor  ability to fly.

EUTROPHICATION  AND AVAILABILITY OF  FOOD
   The  kind of food and its availability are ecological
factors of great importance that determine the distri-
bution  of many  species  of stoneflies.  As already
indicated, large  moss- or algae-covered boulders in
swift streams may provide food for some species of
stoneflies that can withstand a rapid current, whereas
the detritus accumulating  among   loose stones and
gravel  may be  an essential source of food for other
forms.  In the Rocky Mountains there are many clear,
cold,  but intermittent  streams  that would  seem to
provUe  ideal  conditions for stoneflies but that are
literally  biological   deserts.   Many such streams
constitute roaring  torrents in the  spring and early
summer, being  fed by melting snow.   In the late
summer  and  autumn  they may dry up completely.
Most such streams contain so little  nutrient material
as to be completely unable to support enough plant or
animal  life  to serve as food for colonizing stoneflies.

   In some  of these snow-fed trickles or streams that
are  permanent  enough to  establish a scanty diatom
                                cover on the stream bottom, populations of Alloperla,
                                Leuctra,  Capnia,   and Nemoura  may develop and
                                thrive.  By contrast, streams that are more productive
                                or eutrophic may produce far  more food material, but
                                provide a much less suitable  environment, resulting
                                in a  less varied stonefly population.  For example,
                                the upper Yampa River near its headwaters at Yampa,
                                Colorado, is a highly productive stream with a very
                                profuse growth of  algae covering the rocks.  Caddis
                                fly larvae,   Hydropsyche   spp., and  mayfly nymphs,
                                Ephemerella grandis, abound.  Stoneflies are common,
                                but the variety is  not  nearly as great as in a nearby
                                soft-water  stream located in an adjacent drainage.
                                In the Yampa, Alloperla signata and several species
                                of Isoperla  are to be found commonly in  May and
                                June, whereas  in nearby Toponas Creek Leuctra spp.,
                                Nemoura  spp.,  and Alloperla  pallidula dominate the
                                aquatic insect population.

                                POLLUTION

                                  Because of the variety of pollutants that are being
                                released  into our streams and lakes, only brief con-
                                sideration can be given to their effect on stoneflies.
                                Organic wastes can completely eliminate most species
                                of stoneflies through oxygen depletion, by the produc-
                                tion of toxic products of decomposition, or by changing
                                the nature of the substratum.  A dense growth of sew-
                                age  fungus on the bottom of a stream is an unsuitable
                                habitat for most stonefly  nymphs.  Most industrial
                                wastes if present in sufficient  concentration are likely
                                to be toxic.  Hot water from cooling  processes and
                                electrical plants, in sufficient  quantities, can raise the
                                temperature of a receiving  stream above the tolerance
                                levels of most species  of stonefly nymphs.
                                  In bioassays being  conducted at the University of
                                Utah with stoneflies as test organisms, a number of
                                insecticides are proving to  be very toxic to Acroneuria
                                pacifica and Pteronarcys  californica.   Ten different
                                insecticides have been tested to date, representing both
                                the chlorinated hydrocarbon and the organic phosphate
                                groups. When the two species have been compared,the
                                resistance  of Pteronarcys  californica  has been much
                                greater than that of the Acroneuria pacifica.   Large
                                specimens  of both species have been more resistant
                                to poisoning than smaller ones.  This resistance might
                                be a surface-volume  relationship,  or the smaller
                                nymphs might be more susceptible due to the inhibition
                                of critical  enzymes  that aid  in the  molting process.
                                Substances,  such as neotinin, which are known to be
                                in higher concentrations in smaller nymphs than in
                                larger  ones,  might be inhibited by  these pesticides.
                                  Of the insecticides tested,  DDT and aldrin were the
                                least toxic to both species. DDT is  nontoxic  to both
                                species at  a 0.1 ppm  concentration.  Aldrin was not
                                toxic to P. californica at 0.1 ppm, but killed 70 percent
                                of specimens  of A. pacifica  after 96 hours.  Ninety-
                                six-hour TLm  values for DDT for the two species
                                were 1.8 ppm and 0.32  ppm, respectively.

                                   Endrin was the most toxic insecticide tested, being
                                lethal to 100 percent  of the  specimens of A. pacifica
                                after 24 hours of exposure  to a 0.1 ppm concentration.
                                The  same  mortality occurred with  P. californica,
                                but only  after 72 hours of exposure. Ninety-six-hour
                                TLW values for the two species  were 0.00032 ppm
                                for   A. pacifica and 0.0024 ppm for  P.  californica.

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                                Environmental Requirements of Plecoptera
                                              109
                    SUMMARY

   While stoneflies constitute one of the smaller orders
of insects,  they are nevertheless  one of the  most
important groups found in many streams.  In mountain
streams, they are one of the principal sources of food
for trout.   Brinck  (1949) reported that  streams in
Sweden with dissolved-oxygen concentrations below 40
percent saturation had no stoneflies.  Because of their
preference for clean, well-aerated water, they are be-
coming increasingly important  to limnologists  as
indicators  of  clean water  conditions  in pollutional
surveys.

   Practically all of the  work that  has been done to
date on the North American stoneflies  has dealt with
their  taxonomy  and morphology.   The early work of
Claassen in New York and Prison in Illinois revealed
the diversity  of species found in eastern and mid-
western United  States.   More  recently the studies of
Ricker in  Canada, Jewett in the  Pacific  Northwest,
Hansen in  the New  England States, and Gaufin in the
Intermountain Region have advanced our knowledge of
stoneflies in those sections of North America. Despite
the work that has  been done  to  date  the nymphs of
over  50 percent of our North American species have
not yet been described. This is particularly true of our
western species.

   Research conducted by Hynes (1941), Aubert (1946),
and Brinck (1949) in Europe indicates that European
stoneflies differ perhaps more in their ecology than
they  do  taxonomically  or morphologically.  In view
of this finding, detailed  information  about the habitat
requirements and physiological  differences of the
various  species may be quite essential to stonefly
taxonomists  if  they are to separate  the many yet
unidentified forms.

   Most of the ecological data that have been published
concerning both European and North American stone-
flies  consist of  general statements on habitat prefer-
ences.  Prison (1935), for example, stated that certain
species in Illinois were found  only in small streams,
while  others  were found only  in  large streams.  He
also  indicated that the type of  bottom is an important
factor governing the concentrations of different species
of stonefly nymphs.
   Hynes  (1941)  mentioned five major factors  as
controlling the distribution of  stoneflies in England,
namely,  the  movement  of the water, altitude, sub-
stratum, drought, and the possibilities of colonization.
Brinck (1949) considered the following factors as being
most important in  determining the distribution  of
Swedish  stoneflies:  Movement of the water, kind of
substratum, temperature, the amount of certain gases
and compounds in the water, and the  presence of food.
He determined the  water velocity, temperature, dis-
solved-oxygen content,  and pH in a number of streams
and  showed how these factors influenced the distri-
bution of certain species of stoneflies.  He also clas-
sified various stonefly  habitats based  on different
environmental conditions.

   The author has found  that such factors as tempera-
ture, water velocity, bottom type, chemical composi-
tion  of the water,  and abundance  of food are very
important in determining the distribution of stoneflies
in streams of  the Intermountain area.  The environ-
mental requirements of stoneflies may be determined
in artificial streams more precisely than can be done
under field conditions.  The objectives of laboratory
studies conducted during the past three years have been
to determine the effects of low dissolved-oxygen con-
centrations at various  temperatures and stream velo-
cities on  the  gross  activity  of stoneflies,  and to
determine  the  minimum dissolved-oxygen concentra-
tions at which exposure for a prolonged period of time
could be endured without lethal effects.
   Optimal water temperatures for  the species of
stoneflies  tested  to date  have been found to  be  be-
tween 50°  and 60°  F.  In this temperature range  two
species  of stoneflies have been exposed to  oxygen
concentrations as  low  as  1 ppm for 7  days with no
mortality  occurring.    Sensitivity   to low dissolved-
oxygen  concentrations increased rapidly with an in-
crease of temperature above 60° F.
   In the  United States,  pollution, construction of
reservoirs, dredging,  and  water diversion are doing
more to influence the distribution  of stoneflies than
all  other  factors combined.  Concentrations of in-
secticides, such as endrin, which  may  accidentally
pollute our streams and lakes, can be toxic to stonefly
nymphs  at  the unbelievably low concentration  of only
0.00032 ppm.
                                            REFERENCES
Aubert, J. 1946.  Les Plecopteres de la Suisse Rom-
ande. Mitt. Schweiz. Ent.  Gesellsch.  Vol.  20. No. 1,
Lausanne.

Brinck, Per.   1949.   Studies on  Swedish Stoneflies.
Opuscula  Entomologica Supplementum Xi. 246  pp.

Claassen,  P.  W.  1931.  Plecoptera Nymphs of North
America.  Thomas Say Foundation, Baltimore. 199pp.

Prison,  T. H.   1929.   Fall  and Winter Stoneflies,
or  Plecoptera of  Illinois.  111.  Nat. Hist. Surv.  Bui.
18(2): 340-409.
               1935.  The  Stoneflies,  or  Plecoptera
of  Illinois.   111.   Nat. Hist.  Surv.  20(4): 281-471.
Gaufin,  A.  R.  1955.   The Stoneflies of Utah.  Utah
Acad. of Sci., Proc. 32: 117-120.

Gaufin, R. F. and  A. R. Gaufin. 1961.  The Effect of
Low Oxygen Concentrations on Stoneflies.  Utah Aca.
of Sci., Proc. 38: 57-64.
Hanson, J.  F.   1942.   Studies on the Plecoptera of
North America. Ill Allocapnia.  Bull. Brooklyn Ent.
Soc. 27: 81-88.

Hora,  F. L0  1930.  Bionomics and Evolution of the
Torrential Fauna with Special Reference to the Organs
of Attachment.  Phil.  Trans.  R. Soc. London, Series
B, Vol. 218.

-------
110
ENVIRONMENTAL REQUIREMENTS OF AQUATIC INSECTS
Hynes, H. B. N.   1941.   The Taxonomy and Ecology
of the  Nymphs of British Plecoptera. Trans.  Royal
Ent. Soc. of London. 91: 459-557.
Jewett, S. G., Jr.  1956.  Plecoptera.  Aquatic Insects
of California,  pp. 155-181.
Jensen,  L.  D.   1962.   Bioassays to Determine the
Toxicity  of  Insecticides to  Stonefly Naiads. Unpub-
lished  M. S. thesis.  Univ. of Utah Library, 119pp.

Newcomer,  E. J.  1918.  Some Stoneflies Injurious
to Vegetation. J. Agric. Res. 1: 37-42.
                                Schoenemund,  E.  1924.  Plecoptera.  Biologic des
                                Tierre Deutschlands 32: 1-34.

                                                 1925b.  Beitrage zur Biologic der
                                Plekopteren Larven,  mit besonderer Berucksichti-
                                gung der  Atmung.   Arch. Hydrobiol.  15: 339-369.

                                Ricker, W. E.  1943.  Stoneflies of British Columbia.
                                Indiana Univ. Public. 12: 1-145.

                                              1952. Systematic Studies in Plecoptera.
                                Indiana Univ. Public 18:  1-200.
                       ENVIRONMENTAL REQUIREMENTS OF EPHEMEROPTERA
                                          Justin W. Leonard*
   Mayflies,  an ancient  group geologically, have re-
tained sufficient adaptability to continue their occupy-
ing  almost all fresh-water situations, both lotic and
lenitic, from Arctic to Tropics, and from sea level to
above  timberline.  Some species occur over a wide
geographic range and may complete their life cycle
in 1  year in the warmer part of the  range  but require
2 years in the colder portions.

   Our knowledge of  enviromental requirements  of
individual  species is sketchy in the extreme.   For
many  of our North American species, life cycles are
unknown —  immature stages undescribed and total
span of  emergence periods unrecorded -•- and only a
handful  of  species has  been the subject  of detailed
study.

   Ephemeroptera, and in fact most of the so-called
lower orders of aquatics, have received little atten-
tion in North America from  professional entomolo-
gists — little  attention, that is, compared with most
of the terrestrial orders that attracted interest from
the  first because of  the damage  they  did to man's
interests or because of their beauty.

   During  the  early  years  when North American
entomology was, quite understandably, dominated by
purely descriptive taxonomic work, those concerned
with  the lower  aquatic  orders in general and  the
Ephemeroptera in particular, could be counted on one
hanc. with fingers to  spare — Hagen, imported from
Germany to the  Museum of  Comparative Zoology;
Walsh of the University of Illinois,  born and educated
in England; and  Thomas Say, often called the Father
of American Entomology.  Really  significant inroads
on the mayfly fauna of this continent were the achieve-
ment of workers still alive or only recently deceased--
James G. Needham  and his  associates  and students
at Cornell, and, in Canada, J. McDunnough on taxonomy
and  a distinguished  succession of workers at  the
Ontario Fisheries Research Laboratory.
                                   As one reviews historical developments, it is hard
                                to avoid the conclusion that entomology,  as a pro-
                                fession, has  steadfastly refused to  recognize either
                                the economic importance or  general  scientific in-
                                terest of the so-called lower  aquatic  orders.   The
                                vacuum this  neglect created has invited the attention
                                of other disciplines.   So it is  that much of the work
                                on the biology of  these  orders during the last 3 or 4
                                decades has  been performed by scientists who would
                                reluctantly, if at all, identify themselves as entomolo-
                                gists.   Fishery scientists, limnologists, and micro-
                                biologists have contributed the greatest share of our
                                knowledge  to date on the life histories, distribution,
                                and ecology of the Ephemeroptera and their ecological
                                associates.

                                   The  attempt  to  provide  a  scientifically sound
                                rationale for management of fresh-water sport fisheries
                                provided the  initial impetus for such work. The stream
                                surveys  begun by the New York State Conservation
                                Department in the 1920's included sampling of aquatic
                                invertebrates as a routine procedure; this  practice
                                led to  the incorporation of the fish food fauna as a
                                factor in determining the "grade" of a stream for fish
                                management  purposes. Rough  evaluation of the place
                                of various aquatic insects in the fish food cycle and
                                the relative  abundance in different stream situations
                                yielded  data that fishery biologists found useful. When
                                the Michigan Department of Conservation pioneered the
                                concept of trout  stream  improvement in the  early
                                1930's,  top consideration was given to the design and
                                installation of environment-modifying structures that
                                would increase aquatic insect  production as well as
                                create  other environmental conditions favorable to
                                trout.   It is timely  to mention that this important
                                pioneering work took  shape at the hands of our host,
                                Dr. Clarence Tarzwell.

                                   Because so much of the earlier  work on mayfly
                                biology  was associated with fish management, activity
                                was greatest in waters of quality adequate to support
   Michigan Dept. of Conservation, Lansing, Michigan.

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                               Environmental Requirements of Ephemeroptera
                                               111
fisheries of significant value. Pollution due to human
activity  was rarely a factor, and even today we have
much  more knowledge  of  mayfly  distribution  in
"normal" environment than  (when it)  is affected by
allochthonous chemical factors.
   The  respective roles of water temperature, depth,
and  velocity; composition of the  substrate;  aquatic
vegetation  and  drift materials; and characteristics
of the  adjacent  streambank or lake  shoreline, or
both  have  received  frequent attention (see  list  of
references).  Despite the usual overlapping of range
and the adventitious occurrence  of off-site species due
to drifting,  the  experienced collector working  in a
familiar region can usually predict with considerable
accuracy the species composition of the mayfly fauna
in any given site from information on the foregoing
factors.   Several  comprehensive  studies of mayfly
"associations"  in lakes (Lyman,  1956) and streams
(Ricker, 1934;  Sprules,  1947)  have  been made  in
attempts to devise workable systems for ecological
classification.

   Several book-length treatments of mayfly faunas of
states,   covering  Florida (Berner,  1950),  Illinois
(Burks,  1953),  California (Day, 1956),  and Michigan
(Leonard and Leonard, 1962), have appeared within the
past 15  years  in addition to  the continent-wide hand-
book of Needham, Traver, and Hsu (1935) anda check-
list of the  fauna for North America north of Mexico
(Edmunds,  1957a).  The list of references accompany-
ing this paper  is  an  attempt  to  sample the rather
voluminous  literature containing contributions to our
knowledge of North American mayfly biology, ecology,
and economic importance; it excludes  titles  largely
or wholly taxonomic in nature.

   Significantly, only a few of the cited titles deal  with
the effect of pollution on Ephemeroptera at the specific
level, which, it is becoming clear, is the only meaning-
ful level. Reports of death or survival of these insects
under exposure to  a variety  of chemical and physical
insults  are  all too  commonly based on identifications
carried  no  further than order or family;  and even
generic identifications can be misleading. Refreshing
exceptions  are the work of Gaufin and Tarzwell (1952)
and a few isolated but important observations such as
that by Britt (1955a),  who offered one of the  first  and
certainly the most dramatic of  the  warnings  that
eutrophication  of Lake  Erie had already reached a
critical point. Britt found that the unexpected develop-
ment  of thermal stratification in the shallow waters
of Lake  Erie in  the  vicinity of the Bass Islands be-
tween  September 1  and  4,  1953, caused dissolved-
oxygen  concentrations  to  drop as low as  0.70 ppm
near the bottom, with the result that on September 5
he was able  to  count as many as 465 dead Hexagenia
limbata  and  H. rigida nymphs per  square meter.  He
ruled out high  water temperatures as a  factor by
noting that  nymphs  of  these species  survived  "for
days" in shallow laboratory  trays at 29°C  with ade-
quate aeration.

   Sloan (1956), who  plotted  distribution of mayflies
in two springfed Florida streams  according to dis-
solved  oxygen, chlorides, current velocity, pH, and
temperature, noted that the faunas of "springhead"
areas resembled those of organically polluted waters
probably be cause of low oxygen levels in both situations.
   In Michigan we have frequently observed nymphs of
H. limbata and Ephemera simulans  swimming up to
holes chopped in  lake  ice  and under going winterkill.
And during summer  droughts we have observed dis-
tress and  death of nymphs of H. limbata, H. recur-
vata,  and H. atrocaudata in beaver dams apparently
incident  on cessation  of inflow and consequent re-
duction in area and volume.

   Attention should be  called to the finding of Benson
(1955) that mayfly nymphs may be embedded in anchor
ice and, apparently, transported alive for considerable
distances when the ice lifts.
   Too often, when new and unexpected pollution enters
a body of water, the reaction of the mayfly population
cannot be determined because no prior survey informa-
tion  is  available.   Fetterolf (1962) has noted two
instances  where   release of plating  wastes  resulted
in complete fish kills though at  least some mayflies
survived.  In  the  Chippewa River near Mt. Pleasant,
Michigan,  in October 1957,  there was a complete fish
kill involving minnows,  suckers, rock bass, bluegills,
crappie,  and northern  pike.  However, nymphs of H.
limbata and E. simulans survived concentrations  of
0.20  to  0.30  ppm of  cyanide for 1 to 2 hours, and
unidentified species  of Caenis,  Tricorythodes, and
Stenonema survived 0.10 to 0.15  ppm  of cyanide for
2 to 3 hours.   Fetterolf found in a similar episode  in
Hayworth  Creek  near  St. Johns,  Michigan,  in  April
1958, a complete fish kill involving darters, logperch,
common  shiners,  madtoms, suckers, rock bass, and
smallmouth bass.   Here, Caenis sp. survived.  Con-
centrations of at least 2.5 to 3.0 ppm of cyanide were
present for a period of 1 hour, and concentrations  of
0.4 ppm  of cyanide and 0.3 ppm of copper were  found
4 hours  after the  initial slug had passed.  Stenonema
tripunctatum, S. ares,,  and  a Stenonema of the inter-
punctatum group,  as well as two  species of Lepto-
phlebia (presumably cupida and nebulosa), survived
initial concentrations of  at least  2.0 ppm of  cyanide
and concentrations of 0.3 ppm of cyanide and 0.1 ppm
of  copper found  4  hours  later.   Paraleptophlebia
guttata, Baetisbrunneicolor, S.fuscum, and S. vicar -
ium survived where the initial concentration of cyanide
was 2.0  ppm and  that  of copper 1.1 ppm, and where
a concentration of over 1.0 ppm of cyanide was pre-
sent  for  more than 5  hours.   One recently killed
P. mollis was found at this station, and none were  found
alive.

   Figure  1 shows graphically the effect of pollution
sources  and of a primary treatment plant on nutrient
quality, primary  production, and  relative abundance
of mayfly nymphs in  a 3 5-mile stretch  of  the Red
Cedar River upstream from East Lansing, Michigan,
that has  been  studied for several  years by  Prof.
R. C. Ball  and his  group at Michigan State University.
It  should  be noted that fish are (totally) absent from
the stream for  5 or 6 miles downstream from the dis-
charge point of the  plating plant effluent, shown 33
miles above the river  mouth.  Baetine nymphs  make
their  appearance  in small numbers  (0.9 per square
meter) about 2 miles below the  plating plant pollu-
tion source but  ephemerids  (principally Ephemera
simulans)  are  absent for 12 miles, suddenly appear-
ing in large numbers  (188 per square meter). Baetines
appear little  affected  by the treated disposal  plant

-------
112
ENVIRONMENTAL REQUIREMENTS OF AQUATIC INSECTS
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-------
                              Environmental Requirements of Ephemeroptera
                                             113
effluent discharged 18 miles above the river mouth,
averaging 6  per square meter throughout a 2-mile
sampling stretch below the  disposal plant discharge
point.  Ephemerids reappear 6 miles downstream from
the disposal  plant discharge point but become nearly
8 times as numerous 11 miles downstream.

   One of the most exasperating  deficiencies in our
knowledge of mayfly ecology is that concerned with
causes underlying wide variation in production levels
in natural  waters.    In  "natural,"   pollution-free
streams, it  is generally  found that the numbers of
individuals and  volume of  nymphs  (but not neces-
sarily  numbers  of  species)  are  lowest in  sand-
bottom sections,  increase through material of larger
size,  and reach  a maximum in coarse gravel and
rubble and  in  mud  suitable for burrowing  forms.
This is true in the comparative sense, but absolute
production   figures may  vary widely between two
streams  sampled  in what seems, by present know-
ledge,  closely  similar  situations.   I should like to
submit  some  of  my  own hitherto-unpublished data
by way of illustration.  Table 1 lists the total  macro-
invertebrate fauna found in a representative square-
foot sample taken from the  North Branch  of the Au
Sable  River, generally considered  Michigan's  most
productive  trout stream.  Table 2  lists  contents of
a  similar   sample from the West  Branch of the
Sturgeon River,  a stream notably low in production.
The  North  Branch  sample  yielded 1,  374  mayfly
                    Table 1.  STATION 1185, NORTH BRANCH OF AU SABLE RIVER,
                           CRAWFORD CO., MICHIGAN, FEBRUARY 25, 1935
Name
Tubifex
Glossiphonia
Dugesia
Physa
Ancylus
Pisidium
Sphaerium
Orconectes propinquus
Gammarus fasciatus
Hyalella azteca
Heptagenia hebe
Stenonema fuscum
Paraleptophlebia mollis
Baetis cingulatus
Ephemerella invaria,
subvaria
Allocapnia torontoensis
Isoperla signata
Isoperla slossonae
Stenelmis
Phryganea cinerea
Rhyacophila manistee
Hydropsyche sparna,
slossonae
Pycnopsyche lepida
Helicopsyche borealis
Lepidostoma togatum
Antocka saxicola
Tendipedidae
Heleidae
Atherix variegata
Hydrodarina
Totals, 1 square foot
Number
7
7
7
1
1
110
4
1
18
19
17
43
26
11

1,277
8
7
23
80
1
1

120
11
8
23
58
302
37
1
1
2,230
Volume,
cnv*
Trace
0.025
0.025
0.025
Trace
0.125
0.050
3.000
0.400
0.025


0.025


2.400
0.050
0.050
Trace
0.100
Trace
Trace

0.750
1.850
0.025
0.100
1.000
0.300
Trace
0.025
Trace
10.250

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114
                       ENVIRONMENTAL REQUIREMENTS OF AQUATIC INSECTS
 nymphs; of these,  1,277 were  two closely related
 species of Ephemerella, invaria and subvaria, which
 are difficult to distinguish except in late instars.
 The sample shown  in  Table  2 contains much the
 same  association  of  species,  but the  number of
 individuals  and  volume  of nymphs  are negligible
 by comparison.
   Table 4 presents rather detailed chemical analyses
of water from (1) the Au Sable system, (2) the Sturgeon
system, and  (3) the Ontonogon  system.  Both (1)
and  (2) are typical  hard-water  streams  that  flow
through glacial  drift  topography  in the northern
Lower Peninsula; (3) is a soft-water stream charac-
teristic of  the  Pre-Cambrian  formations  of  the
western  Upper  Peninsula and is  between (1) and
(2) in trout production.
                    Table 2.  STATION 1160, WEST BRANCH OF STURGEON RIVER,
                           CHEBOYGAN CO., MICHIGAN, JANUARY 21, 1935
Name
Physa
Pisidium
Emphemerella invaria,
subvaria
Paraleptophlebia mollis
Baetis cingulatus
Baetis vagans
Heptagenia hebe
Rhithrogena jejuna
Capnia vernalis
Isoperla dicala
Hydroperla olivacea
Stenelmis
Glossosoma americana
Rhyacophila manistee
Micrasema rusticum
Oxyethira sp.
Anthocha saxicola
Simulium venustum
Tendipedidae
Atherix variegata
Totals, 1 square foot
Number
1
1

43
1
17
5
1
14
5
15
1
15
290
3
3
3
7
3
12
2
442
Volume,
cm3
Trace
Trace




0.075



0.025

0.025


0.075



0.025

0.225
    Table  3,  showing the mayfly  yields of samples
 taken from  the North  Branch  in  February,  April,
 and  May, is  included  here  chiefly to  show  that
 changes  in  the  mayfly  fauna are  what  might be
 expected from normal seasonal succession.
   It  is  difficult to  account for  the wide disparity
in bottom-fauna production between (1) and (2) on
the basis of water chemistry. The physical charac-
teristics of the two streams are  superficially quite
similar,  and the bottom samples were taken in gravel
of closely  comparable  size.  About the only visible
difference  is that the gravel in the West Branch of
the Sturgeon is smooth and polished,  while that in
               Table 3. COMPARATIVE OCCURRENCE OF EPHEMEROPTERA NYMPHS IN
           NORTH BRANCH OF AU SABLE RIVER, MICHIGAN, LATE WINTER TO SPRING (1935)

Ephemerella invaria and subvaria
Ephemerella lata
Paraleptophlebia mollis
Baetis cingulatus
Heptagenia hebe
Stenonema fuscum
Stenonema canadense
February 25
Number
1,277
0
26
11
17
43
0
Volume
2.400
0
Trace
Trace
Trace
0.025
0
April 25
Number
711
68
54
23
43
85
27
Volume
2.100
0.050
0.050
0.050
0.025
0.200
0.025
May 19
Number
157
87
18
0
0
1
61
Volume
0.900
0.150
0.025
0
0
Trace
0.025

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                               Environmental Requirements of Ephemeroptera
                                             115
         Table 4. WATER ANALYSES FOR THREE MICHIGAN STREAMS OF VARYING PRODUCTIVITY
            SAMPLED FROM AUGUST 19 - SEPTEMBER 2, 1958, BETWEEN 1:00 AND 4:00 p.m. a

Stream
Au Sable,
Crawford Co.
Sturgeon,
Cheboygan Co.
Ontonogon,
Gogebic Co.

Stream
Au Sable,
Crawford Co.
Sturgeon,
Cheboygan Co.
Ontonogon,
Gogebic Co.

Stream
Au Sable,
Crawford Co.
Sturgeon,
Cheboygan Co.
Ontonogon,
Gogebic Co.
Temp,
Water
54

57

69

°F,
Air
68

68

80

Conductivity
nmho, 18°C
256


305


151


Nitrogen,
ppm
0.64

1.26

1.04








Oxygen,
ppm
9.0

10.9

12.0

Sodium, P
ppm
0.9

1.5

1.2

Phosphorus

13.9

20.3

33.1

Carbon dioxide,
ppm
0.0

0.0

0.0

otassium,
ppm
0.7

0.6

1.1

Alkalinity,
Phenolphthal e in
6.0

5.0

3.0

Calcium, Magnesium,
ppm ppm
52.2 7.9

71.3 12.0

26.3 5.3

(total soluble),
ppb
1.7

1.9

2.0

Methyl orange pH
155

181

83

8.2

8.4

7.4

Iron, Aluminum, Silicaj
ppb ppm ppm
5 tr 5.0

172 tr 6.0

172 0.04 8.1

Halogen (total), Chloride,
ppm ppm
3.6 3.55

1.2 0.89

— —

Sulfate,
ppm
9.2

12.6

7.8

 a From Urshel and Hopper, 1961.

the North Branch of the Au Sable is thickly encrusted
with a porous, easily crumbled, calcareous deposit.
This deposit supports occasional tufts  of  Fissidens
on its rough, irregular surface,  and both the surface
and the  porous interior offer much more  harborage
for organisms than does the smooth surface of the
bare gravel of the Sturgeon.  Further, the  porosities
of the Au Sable  deposits are lined with algal growth.
To use  a rather crude comparison, a  section of the
deposit  resembles  a  slice  of  Roquefort  cheese.
   We  have been  unable  to devise a  method of
computing the  total surface available to organisms,
per  square foot of bottom, in  the  North Branch.
But  far more  baffling is  our  inability to explain
the presence  of the  calcareous deposit  there  and
its absence from the West  Branch of  the Sturgeon.
   Table 5 represents an attempt to show the eco-
logical  distribution of mayfly  nymphs  in  Michigan
trout  streams.    The categories used are  rather
broad  but  are practical  and helpful for  the field
collector and fish management worker.
   My  purpose in outlining this problem  is to em-
phasize  the  inadequacy of our  knowledge of  the
environmental  requirements of  mayflies.   There
is a clear  need for intensive work on microhabitats
and for evaluation of  the effects of different types of
pollution on  the  habitat and the individual species
themselves.  Present knowledge of mayfly taxonomy
and  life cycles,  while far  from complete, provides
an  adequate  foundation for such intensive study.
       Table 5. ECOLOGICAL DISTRIBUTION OF MAYFLY NYMPHS IN MICHIGAN TROUT STREAMS
 Sand and gravel (burrowing nymphs)

  Ephemera simulans

 Mud (burrowing nymphs)

  Hexagenia limbata
  Hexagenia atrocaudata (beaver ponds)
  Hexagenia recurvata  (cold streams)
  Hexagenia rigida (warm streams)
Gravel and rubble

 Ephemerella cornuta  (Pre-Cambrian bedrock
    streams)
 Ephemerella dorothea
 Ephemerella excrucians
 Ephemerella invaria
 Ephemerella lata
 Ephemerella rotunda
 Ephemerella subvaria

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116
ENVIRONMENTAL REQUIREMENTS OF AQUATIC INSECTS
 Table 5'.  ECOLOGICAL DISTRIBUTION OF MAYFLY NYMPHS IN MICHIGAN TROUT STREAMS (CONTINUED)
  Paraleptophlebia adoptiva
  Paraleptophlebia debilis
  Paraleptophlebia mollis
  Paraleptophlebia praepedita (warm streams)
  Baetis brunneicolor
  Baetis cingulatus
  Baetis intercalaris (also plant beds)
  Baetis vagans
  Pseudocloeon anoka
  Epeorus vitreus  (fast water only)
  Rhithrogena jejuna
  Rhithrogena impersonata
  Rhithrogena pellucida
  Rhithrogena sanguinea

Underside of stones

  Ephemerella walkeri (more often in leaf drift)
  Stenonema canadense (also in leaf drift in fast
   water)
  Stenonema fuscum
  Stenonema frontale (also in leaf drift)
  Stenonema integrum (fast water only)
  Stenonema ithaca
  Stenonema luteum (fast water only)
  Stenonema nepotellum (fast water only)
  Stenonema pulchellum (more often on submerged
   logs)
  Stenonema vicarium (also in leaf drift)
  Heptagenia hebe  (oftener in leaf drift)

Submerged plant beds

  Ephemerella needhami  (also leaf drift and sub-
   merged logs)
  Callibaetis ferrugineus  (quiet  water only)
  Baetis hiemalis  (quiet water only)
  Baetis intercalaris (oftener in gravel
   riffles)
  Baetis pygmaeus

 Leaf drift and detritus, nonburrowing  nymphs
  Ephemerella deficiens
  Ephemerella needhami
    beds)
 (also in submerged plant
  Ephemerella walkeri (also under stones)
  Stenonema canadense (also under stones)
  Stenonema frontale (also under stones)
  Stenonema pulchellum (prefers submerged logs)
  Stenonema tripunctatum
  Stenonema vicarium (also under stones)
  Heptagenia hebe (also under stones)
  Heptagenia pulla

Detritus, little or no current

  Tricorythodes  spp. (cold streams)
  Brachycercus lacustris (warm streams)
  Caenis forcipata  (spring-holes)
  Caenisjocosa
  Caenis simulans
  Ephemerella deficiens
  Ephemerella lutulenta
  Ephemerella needhami  (also leaf drift and plant
   beds)
  Ephemerella simplex
  Ephemerella temporalis
  Baetisca laurentina (cold streams)
  Baettsca obesa (warm streams)
  Leptophlebia cupida
  Leptophlebia nebulosa
  Stenonema heterotarsale

Quiet water, free-swimming nymphs

  Siphlonurus alternatus
  Siphlonurus quebecensis
  Siphlonurus rapidus
  Centroptilum album  (warm streams)
  Cloeon sp.
  Metretopus borealis (Pre-Cambrian bedrock
   streams)

Moderate to fast current, free-swimming
  nymphs

  Isonychia bicolor
  Isonychia harperi
  Isonychia sadleri
  Siphloplecton basale
                                            REFERENCES
Adamstone, F. B.  1923.   The Bottom fauna of Lake
Nipigon.    Univ.  Toronto  Studies,  Biol. 24.   Publ.
Ont. Fish. Res. Lab., 19:43-70.
                 1924. The distribution and economic
importance of the bottom fauna of Lake Nipigon with an
appendix on the bottom fauna of Lake Ontario. Univ.
Toronto Studies, Biol. 25. Publ. Ont. Fish. Res. Lab.,
24:33-100.
Adamstone, F. B., and W. J. K. Harkness. 1923. The
bottom  organisms  of  Lake Nipigon.  Univ. Toronto
Studies,  Biol.  22.  Publ.  Ont.  Fish.  Res, Lab.,  15:
121-170.
                                Ball, Robert C.  1948. Relationship between available
                                fish food, feeding habits of fish and total fish production
                                in  a  Michigan lake. Techn. Bull. 206, Michigan State
                                College Agr. Exp. Sta., pp. 1-59.


                                Benson, Norman G.  1955.  Observations on anchor ice
                                in  a Michigan  trout stream.   Ecol., 36 (3):529-30.
                                Berner, Lewis  1950.  The mayflies of Florida, Univ.
                                Florida Stud., Biol. Ser. 4(4):279 pp.

                                               1959.  A tabular summary of the bio-
                                logy of North American mayfly nymphs (Ephemerop-
                                tera).  Bull. Florida State Mus., 4(l):l-58.

-------
                                Environmental Requirements of Ephemeroptera
                                               117
Britt,  N. Wilson.  1955a.  Stratification of western
Lake  Erie in summer of 1953: effects  on the Hexa-
genia  (Ephemeroptera)  population.    Ecol.,  36(2):
239-244.

                   1955b.  New methods of collecting
bottom fauna from shoals or rubble bottoms of lakes
and streams.  Ecol., 36 (3):524-25.

Burks, B. D. 1953.  The mayflies, or Ephemeroptera,
of Illinois.   Bull. 111.  Nat. Hist. Surv. 26(1):1-216.

Clemens, W. A.  1913. New species and life histories
of Ephemeridae or mayflies. Canad. Ent., 45:246-262.

Day, W. C.  1956.  Ephemeroptera in: Aquatic Insects
of California, R. L. Usinger,ei al., Univ. Calif. Press,
pp.  79-105.

Edmunds, George F.,  Jr.   1957a.  A checklist of the
Ephemeroptera  of North America north of Mexico.
Ann. Ent. Soc. Amer., 50:317-324.

                            The  predaceous mayfly
nymphs  of North America.  Proc.  Utah Acad. Sci.,
Arts,  Letters, 34:23-24.

Fetterolf, Carlos M., Jr. 1962.  (Personalcommunica-
tion)

Forbes,  S. A. 1888a.  On the food relations of fresh-
water fishes;  a  summary and  discussion.  Bull. 111.
State Lab. Nat. Hist., 2:475-538.

               1888b.  Studies of the food of fresh-
water  fishes.    Bull.    111.  State  Lab. Nat. Hist.,
2:433-473.

Gaufin, A.  R.,  and C. M.  Tarzwell  1952. Aquatic
invertebrates as indicators of stream pollution.  U. S.
Pub. Health Service  Rept. 67:57-64.

Hankinson,  T_  L., J.  G.  Needham, and C. A. Davis.
1908.   A biological survey of Walnut Lake, Michigan.
Report  of Geological Survey  of Michigan  for 1907,
pp.  230-263.

Hunt,  Burton P.  1951. Reproduction of the burrowing
mayfly,  Hexagenia  limbata (Serville),  in Michigan.
The Florida Ent.,  34:59-70.

                1953. The  life history and economic
importance of a burrowing mayfly, Hexagenia limbata,
in southern Michigan lakes.  Mich. Dept. Cons., Inst,
Fish.  Res., Bull.  4:1-151.

Ide, F.   P.   1930.   Contribution  to the biology of
Ontario  mayflies with descriptions of new species.
Canad. Ent. 62:204-213.

            1935.   The  effect of temperature on the
distribution of the mayfly fauna of a  stream. Univ.
Toronto  Studies,  Biol. 39.   Publ. Ont. Fish. Res.
Lab., 50:3-76.
            1940.  Quantitative determination of the
insect fauna of  rapid water.   Univ. Toronto Studies,
Biol.  Ser.  47,  Pub.  Ont.  Fish.  Res.  Lab.,  59:1-20.

Leonard,  Justin W,, and  Fannie  A.  Leonard   1962.
Mayflies of Michigan trout streams.  Cranbrook Inst.
Sci. Press,  151 pp.

Lyman, F.  Earle. 1956.   Environmental factors af-
fecting  distribution  of  mayfly  nymphs  in  Douglas
Lake, Michigan.  Ecol., 37 (3):566-76.

Morgan, Ann H.  1911.  Mayflies of Fall Creek.  Ann.
Ent. Soc. Amer., 4:93-119.

                  1913.  A contribution to the biology
of  mayflies.    Ann.  Ent. Soc.  Amer.,  6:371-413.

Murphy, Helen E. 1922.  Notes of the biology of some
of our  North American species of mayflies.   Bull.
Lloyd Library 22, Ent. Ser. 2:1-39.

Neave,  Ferris  1932.  A study of the mayflies (Hexa-
genia)   of  Lake Winnipeg.   Contrib. Canad.  Biol.
Fish., N. S., 7:179-201.

                1934.   A  contribution to the aquatic
insect fauna of  Lake Winnipeg.   Inter.  Revue der
gesamten  Hydrobiologie und  Hydrographie, 31:157-
170.

Needham, James G.  1920.  Burrowing mayflies of our
larger  lakes  and streams.  Bull. U. S.  Bur. Fish.,
36:267-292.

Needham, James G., and C. B. Betten  1901.  Aquatic
insects in the Adirondacks. Bull. N. Y. State Museum,
47:383-612.

Needham,  James G.,  Jay  R.  Traver,  and Yin-Chi
Hsu,    1935.   The  biology of mayflies,  Comstock
Pub. Co.,  N. Y., 759 pp.

Rawson, Donald  S.  1930.   The bottom fauna of Lake
Simcoe and its  role in the ecology of the lake.  Univ.
Toronto Studies,  Biol. 34.   Publ.  Ont. Fish. Res.
Lab.,  40:1-183.

Ricker, William E.   1934. An ecological classifica-
tion of  certain Ontario  streams.    Univ.  Toronto
Studies, Biol. 37, Publ. Ont. Fish. Res. Lab., 49:1-114.

Sloan,  William C.  1956.  The distribution of aquatic
insects in two Florida springs.   Ecol., 37(l):81-98.

Sprules, Wm. M.  1947.   An ecological investigation
of stream insects in Algonquin Park,  Ontario.  Univ.
Toronto Studies, Biol. 56.  Publ. Ont. Fish. Res.  Lab.,
69:1-81.

Urshel, Naylord L., and  Frank F.  Hooper.   1961.
Analysis  of hatchery water  supply samples.  Inst.
Fish.  Res.  Rept. No. 1634:1-17.  Mich. Dept. Cons.
(multilith).

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118
ENVIRONMENTAL REQUIREMENTS OF AQUATIC INSECTS
                        ENVIRONMENTAL REQUIREMENTS OF TRICHOPTERA
                                           Selwyn S. Roback*
                  INTRODUCTION

   I  should like,  in this talk, to present some of the
tolerances to  chemical factors and limitations of the
caddisfly  fauna of our  streams  and rivers.   The
purely physical habitat preferences are well reported
in the literature  (Ross,  1949;  Betten, 1934; Lloyd,
1921)  and need not be repeated here; Hynes  (1960)
has summarized  the data on caddisfly tolerances and
habitat to that date.  It was felt to be more pertinent
to present these previously unreported data that have
been gleaned from over 10 years of stream survey
reports.

   Before going into the chemistry, we might examine
the importance of the caddisfly larvae as an element
of stream fauna  and the relative abundance  of the
commonly found  families.   An examination  of the
species lists  from  our  surveys  revealed  that the
caddisfly  larvae formed 8 to 13 percent of the fauna
of any river  studied.   The  average was  about 10
percent.

   Table 1 gives the relative abundance of the common
caddisfly  families from the aspects of both frequency
of occurrence and population.  The  caddisfly fauna
of 10 rivers,  ranging from Center Creek, Missouri,
to the St.  Lawrence at Brockville, were tabulated. The
last  column is a subjective  estimate  of the relative
abundance, based on my experience.  The table shows
that  the  first  four  families dominate the caddisfly
fauna both from frequency of occurrence and popula-
                                 tion.    The fifth family, the Philopotamidae, repre-
                                 sented  by the  genus  Chimarra,  though having few
                                 species per river, is usually abundant where present -
                                 more  so than the  Psychomyiidae or Limnephilidae.

                                                    CHEMISTRY

                                   Tables 2 through 15 were made by taking the chemi-
                                 cal data from about 100 stations on 25 rivers in the
                                 United  States and Canada and recording the occurrence
                                 of  each  of  the  genera  involved at  each of these
                                 stations.    These  data were  coded  and fed into a
                                 computer that gave the number of times each genus
                                 occurred at a certain range for each chemical.  For
                                 example, in Table 2  Chimarra appeared 3  times at
                                 stations with an alkalinity of 10 ppm or less, 7 times
                                 at alkalinity between 11 and 20 ppm,  5 times between
                                 21  and 30  ppm, etc.   While  the rivers studied do
                                 represent a good cross-section of the  rivers in the
                                 United  States and Canada, there is a bias introduced
                                 into these  tables because certain rivers have been
                                 studied more frequently than others, and this tends to
                                 elevate certain  columns  artifically:  Most of the
                                 tables represent 600 or more records.

                                   Alkalinity - M.O.:   Table 2 shows that alkalinity
                                 per se is not a particularly  significant  factor in the
                                 appearance of caddisfly larvae.  Most  of the genera
                                 can  tolerate  a range  of from  about  20 to  100 ppm.
                                 The peaks  in distribution at concentrations  of 30 and
                                 100  ppm are artificial.  They are caused by the more
                                 frequent collection from certain rivers at those ranges.
          Table 1.  RELATIVE ABUNDANCE OF COMMON CADDISFLY FAMILIES OF 10 RIVERS
Caddisfly families
Hydropsychidae
Psychomyiidae
Limnephilidae
Leptoceridae
Philopotamidae
Hydroptilidae
Brachycentridae
Glossossomatidae
Helicopsychidae
Molannidae
Lepidostomatidae
Phryganeidae

Number of
rivers
9
8
8
7
5
7
3
2
1
1
1
2

Species
per
rivers
3.9
2.4
2.1
5.0
1.6
1.7
1.0
1.0
1.0
1.0
1.0
1.5

Estimated relative
abundance,
percentage
80
3
2
10
4
0.1
0.2
0.1
0.2
0.1
0.1
0.2
100
 * Department of Limnology, Academy of Natural Sciences of Philadelphia, Philadelphia, Pennsylvania.
                                                                                                 GPO 816-361—5

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                               Environmental Requirements of Trichoptera
                                           119
            Table 2.  FREQUENCY OF OCCURRENCE OF CADDISFLY GENERA AT DIFFERENT
                     LEVELS OF METHYL ORANGE ALKALINITY (669 RECORDS)
Caddisfly
genera
Chimarra
Neureclipsis
Phylocentropus
Polycentropus
Psychomyiid sp.
Cheumatopsyche
Hydropsyche
Macronemum
Hydroptila
Athripsodes
Leptocella
Mystacides
Oecetis
Triaenodes
Pycnopsyche
Ptilostomus
Molanna
Helichopsyche
Brachycentrus
Lepidostoma
Totals
Methyl orange alkalinity,
10
3
1
5


3
2
3
1



2
2
4

1

5
3
35
20
7
7
2
2

12
14
14
5
6
11

7
3
5

2
1
4
1
103
30
5
8
2
2
13
8
18
21
3
8
16

8
6




1

119
40

5

2
4
4
11
5

3
2

1
1
1





39
50




1
2
4
1


2

1


1




12
100

18
2
10
13
24
32
21
12
12
19
4
22
6
15
3
4
9
6

232
ppm
150
1
6
4
2

8
9
6
1

7
4
7
6
4

1

1

67

200
1
4

1
2
3
11

2
1
3

5
1
1


2


37

550

2

1
1
1
6

2

3

3
1
3


2


25
   Cl~:   Table  3  shows that 8 of the 20 genera can
tolerate a chloride concentration of over 2,500 ppm.
This is  equivalent to a salinity concentration of 4,500
ppm.  This is within the mesohaline category of Redeke
(1922).  The net makers appear to be slightly more
common at these high salinities.  The genus labelled
Psychomyiid sp. is close  to  Psychomyiid genus A
Ross and is relatively common at stations with a high
salinity.
          Table 3. FREQUENCY OF OCCURRENCE OF CATTISFLY GENERA AT DIFFERENT
                                 CHLORIDE LEVELS (671 RECORDS)
Caddisfly
genera
Chimarra
Neureclipsis
Phylocentropus
Polycentropus
Psychomyiid sp.
Cheumatopsy che
Hydropsyche
Macronemum
Hydroptila
Athripsodes
Leptocella
Mystacides
Oecetis
Triaenodes
Pycnopsyche
Ptilostomus
Molanna
Helichopsyche
Brachycentrus
Lepidostoma
Totals

1
1
1
2


1
2
4


1



1



2

15

3
5
9
4
2
6
8
17
18
8
11
10

5
3
7
1
2

6
4
126

5
2
13
1
1

13
17
16
4
8
11

8
4
5


4
1

108
Chloride
10
7
5
2
2
16
15
24
15
8
5
17

18
8
5
2
2
1
2

154
concentration, ppm
50
1
16
6
14
6
25
32
16
6
5
18
8
22
9
15
1
4
9
6

219
100 500

5 1


2 1
2
11 1
1 1
1
1
3 1

2







28 5
2,500 10,000
1
1

1
2 1
2
3



2


2
1





3 13

-------
120
ENVIRONMENTAL REQUIREMENTS OF AQUATIC INSECTS
   CO2:  In table  4 we see that  eight  genera  can
tolerate CO2 concentrations  over  40 ppm.  The gap
from 21 to 40 ppm is artificial because no stations
collected had 062 concentrations in that range. Most
of the  genera found about  40 ppm are  case  makers.

   DO: Only 6 of the 20 genera occurred at a DO level
                               of less than 3 ppm (Table 5). The gap at 3 is artificial.
                               Cheumatopsyche and Hydropsyche have been recorded
                               as tolerant of organic pollution and their presence at
                               low DO concentrations is not surprising. The presence
                               of Molanna and Helichopsyche, is, however, unusual.
                               These genera are usually found in clear, cold streams
                               with a sand or gravel bottom.
               Table 4. FREQUENCY OF OCCURRENCE OF CADDISFLY LARVAE AT DIFFERENT
                              CARBON DIOXIDE LEVELS (371 RECORDS)
On rl/^i c*f 1 T*
cauaisiiy
genera
Chimarra
Neureclipsis
Phylocentropus
Polycentropus
Psychomyiid sp.
Cheumatopsyche
Hydropsyche
Macronemum
Hydroptila
Athripsodes
Leptocella
Mystacides
Deceits
Triaenodes
Pycnopsyche
Ptilostomus
Molanna
Helichopsyche
Brachycen'rus
Lepidostom .
Totals


1
1
1



1
1



1


1






r*
\-
Carbon dioxide concentrations,

5 10 20 30 40
5 9 1
10 18
1 5 1
2 4
9 12
11 19 1
28 36 1
15 29 1
5 8
7 11
10 24 1

8 18 1
471
4 8 1
1
1 2
2 3
261
3
125 220 12 0 0
Table 5. FREQUENCY OT -.' .CURRENCE OF CADDISFLY GENERA AT
DISGO, /ED

Caddisfly
genera
Chimarra
Neureclipsis
Phylocentropus
Polycentropus
Psychomyiid sp.
Cheumatopsyche
Hydropsyche
Macronemum
Hydroptila
Athripsodes
Leptocella
Mystacides
Oecetis
Triaenodes
Pycnopsyche
Ptilostomus
Molanna
Helichopsyche
Brachycentrus
Lepidostoma
Totals
OXYGEN LEVELS (601 RECORDS)
ppm

50
1

1









1
1
1

1

1
1
8
DIFFERENT

Dissolved oxygen concentrations, ppm


1





1
1


1
1





1
1


6


35 7 9 11
494
1 12 22 9
1 12 2
1 2 4 13
16 13
2 12 24 19
3 29 36 27
1 15 36 12
6 10 4
3 16 6
2 20 20 13
4 4
2 16 19 12
1 7 11 3
2 20 7
1 3
4 3
153
1 9 7
2 2
0 13 148 276 153


15





1
1

2





1





5

-------
                              Environmental Requirements of Trichoptera
                                            121
   Fe:  Like alkalinity, iron (Table 6) is of practically
no significance in the distribution of caddisfly larvae.
Most of the genera occur over the entire range found
in the streams and rivers studied.  Even some of the
less  common genera were found over a wide range of
iron concentrations (cf. Lepidostoma).
   Total Hardness: Only 4 of the genera listed (Table
7) were found at hardness values above 2,500 ppm.  The
gap at from 1,001 to 2,500 ppm is unfortunate, but we
can presume that the genera  found above 2,500 ppm
would also be found there. Only one of four  genera
above 2,500 ppm was a case maker.
           Table 6.  FREQUENCY OF OCCURRENCE OF CADDISFLY GENERA AT DIFFERENT
                                  LEVELS OF IRON (422 RECORDS)
Caddisfly
genera
Chimarra
Neureclipsis
Phylocentropus
Polycentropus
Psychomyiid sp.
Cheumatopsyche
Hydropsyche
Macronemum
Hydroptila
Athripsodes
Leptocella
Mystacides
Oecetis
Triaenodes
Pycno psyche
Ptilostomus
Molanna
Helicopsyche
Brachycentrus
Lepidostoma
Totals

0.01
2
7

2
2
6
9
8
4
4
6
1
5
2
2





60

0.03
2
5
2
4
1
9
14
7
6
1
8
2
7
1
7
3
3
5
3

95
Iron
0.05
3
6
2
1
6
5
14
10
6
5
3

5
2
3

1
1
3
1
77
concentration,
0.07

2
1
1
1
4
4
2
1
1
2

1
1
1

1
1
2
1
27
0.1
1
1
3
1
1
2
3
7
1
3
2

2

1


1
2
1
32
ppm
0.4
5
7
1
2
3
9
15
8
4
3
15

7
5
5
1


1
1
92

0.7
2
2
1

2
3
3
1
1
1
1

3
2


2

2

26

1.0
1

1
1
4

1


1
1

1
1






12
           Table 7. FREQUENCY OF OCCURRENCE OF CADDISFLY GENERA AT DIFFERENT
                           LEVELS OF TOTAL HARDNESS (667 RECORDS)
Caddisfly
genera
Chimarra
Neureclipsis
Phylocentropus
Polycentropus
Psychomyiid sp.
Cheuma topsy che
Hydropsyche
Macronemum
Hydroptila
Athripsodes
Leptocella
Mystacides
Oecetis
Triaenodes
Pycnopsyche
Ptilostomus
Molanna
Helichopsyche
Brachycentrus
Lepidostoma
Totals
Total hardness,
5 10
1 3
2
5


2
1 6
1 6

2
1 2

1
1
1 3

1 1

5
2
6 41
50
10
18
4
5
14
24
36
36
9
15
24

16
9
5
1
1
1
5
2
235
100

7

1
10
10
17
8
9
4
12
1
12
4
4
2

4


105
150
1
9
2
4
4
12
13
10
2
8
7
2
7
4
12
1
4
4
3

109
200

7
4
7

10
12
8
3

8
5
11
4
4

1
1
4

89
ppm
500

7

2
3
5
16
2
1
1
7

6
2
2


1


55

1,000 2,500
1


1
3
1
3

3



2

2


3


19 0

5,000
1




2
3






2






8

-------
122
ENVIRONMENTAL REQUIREMENTS OF AQUATIC INSECTS
         :  The caddisfly larvae (Table 8) appear to
be well  distributed over the range from<0.001 ppm
to 1.0 ppm.   Above this they drop off and only four
genera are found at levels above 10.0  ppm.  The
presence of Brachycentrus, a cool-clear-water form,
at NH3   concentrations  above  10.0  is  surprising.
                                NO3-N:   Unlike NHg, the distribution records  in
                              Table  9 are largely clustered in the (0.014 ppm to
                              0.7 ppm) middle range of concentrations.  Here there
                              appears  to  be  both  upper  and lower limits to the
                              optional concentrations of NO3.  There are only scat-
                              tered records below  0.014 ppm and above 0.7 ppm.
           Table 8. FREQUENCY OF OCCURRENCE OF CADDISFLY GENERA AT DIFFERENT
                            AMMONIA NITROGEN LEVELS (665 RECORDS)
Caddisfly
genera
Chimarra
Neureclipsis
Phylocentropus
Polycentropus
Psychomyiid sp.
Cheuma topsyche
Hydropsyche
Macronemum
Hydroptila
Athripsodes
Leptocella
Mystacides
Oecetis
Triaenodes
Pycnopsyche
Ptilostomus
Molanna
Helichopsyche
Brachycentrus
Lepidostoma
Totals
Ammonia nitrogen
0.001
2
9
5
4
4
10
14
12

1
8
4
9
5
8

1

5

101
0.009
4
13
3
4

16
15
14
6
12
15

11
10
8
3
2
5
2
2
145
0.03 0.
5
9
2
2
1
16
24
12
3
7
16
3
11
4
6

2
3
4
1
131
concentrations,
05
2
5
1

1
3
7
5
1
3
2
1
2

3



1
1
38
1.0
2
14
3
10
26
17
42
26
15
6
18

21
4
5
1
2
5
4

221
ppm
10.0
2
1
1

2
2
3
1
1
1
3

2
3
2

1



25

20.0






1
1


1







1

4
           Table 9.  FREQUENCY OF OCCURRENCE OF CADDISFLY GENERA AT DIFFERENT
                         LEVELS OF NITRATE NITROGEN (665 RECORDS)
Caddisfly
genera
Chimarra
Neureclipsis
Phylo centropus
Polycentropus
Psychomyiid sp.
Cheumatopsyche
Hydropsyche
Macronemum
Hydroptila
Athripsodes
Leptocella
Mystacides
Oecetis
Triaenodes
Pycnopsyche
Ptilostomus
Molanna
Helichopsyche
Brachycentrus
Lepidostoma
Totals

0.001
1





1
1


1



1

1



6
Nitrate nitrogen
0.007 0.013 0.03 0

1
1 1
3
2
1 2
3
1
3
1
4
1
4
2


1
1
1

concentrations, ppm
.07
2
12
4
4
14
13
20
12
1
7
8
2
8

7

3
4
4
2
3 1 29 127
0.2
8
21
3
8
11
23
48
40
9
15
35

26
12
12

1
4
9
1
286
0.7
6
17
6
3
2
23
29
17
8
7
15
4
18
12
12
1
2
4
3
1
190
1.5




5
1
3

5


1



1




16
3.0



2

1
2








2




7

-------
                               Environmental Requirements of Trichoptera
                                             123
   pH:   Most-of  the genera in Table 10 are recorded
at pH values between 6.0 and 9.0.  None of the rivers
collected has  a  pH value  more than 9 or in the 3.0
to 5.5 range. We can presume that since six genera
are represented  at  pH < 3.0,  some of  these  would
carry through to 5.5  if  collections were  made in
suitable streams  or rivers.
   PO^:  The distribution records at different phos-
phate levels (Table 11) are spread from 0.002 to 0.5
ppm. Below 0.002, only four genera of net makers are
found.  Above 0.5, especially at 5.0 ppm,  the case-
maker genera are more common. Only Hydropsyche
carries through the entire range.
          Table 10.  FREQUENCY OF OCCURRENCE OF CADDISFLY GENERA AT DIFFERENT
                              HYDROGEN IRON LEVELS (666 RECORDS)
/^_-1 JJ_,J1
Caddisfly
genera
Chimarra
Neureclipsis
Phylocentropus
Polycentropus
Psychomyiid sp.
Cheuma top syche
Hydropsyche
Macronemum
Hydropttla
Athripsodes
Leptocella
Mystacides
Oecetis
Triaenodes
Pycnopsyche
Ptilostomus
Molanna
Helichopsyche
Brachy centrus
Lepidostoma
Totals
pH values

3.0 4.5


1


1

1

1


1





1

6 0

5.0 5.5 6.0 6.5
1 2
1
1 5


4
2
4
1



1 2
1 2
1 3

1 1

1 6
1 2
0 0 8 35
Table 11. FREQUENCY OF OCCURRENCE OF CADDIFSLY GENERA
PHOSPHATE
y~1_ JJ*_JTT
Lactaisiiy
genera
Chimarra
Neureclipsis
Phylocentropus
Polycentropus
Psychomyiid sp.
Cheumatop syche
Hydropsyche
Macronemum
Hydropttla
Athripsodes
Leptocella
Mystacides
Oecetis
Triaenodes
Pycnopsyche
Ptilostomus
Molanna
Helichopsyche
Brachy centrus
Lepidostoma
Totals
LEVELS (646 RECORDS)

7.5
10
20
3
6
20
22
48
39
10
11
31
1
16
7
4
2

1
1
1
258
AT


8.0
3
19

4
13
20
36
16
11
8
18

22
12
17

1
8
1

209

9.0

10
6
10
1
19
20
10
5
5
13
7
14
4
8
2
4
5
7

150
DIFFERENT


Phosphate concentrations, ppm

0.001 0.005

2 4
2
2
18
1 8
3 15
3 12
2
2
7

7
4
2


2
1

9 88

0.01 0.05 0.1 0.5
1925
9 14 18 3
6 6
3654
1294
8 18 15 12
13 27 21 19
8 21 20 2
2 6 10 5
6 13 6 2
5 19 17 12
341
7 17 14 10
4674
4 7 11 4
2 1
4 1 3
54 2
662
2 1
76 192 173 95

1.0





1
2













3

5.0






2
1
1

1

1
1

1


1

9

10.0






1













1

-------
124
ENVIRONMENTAL  REQUIREMENTS OF AQUATIC INSECTS
   Temperature:  Temperature, at least at the gradi-
ents found in our work (Table 12), does not seem to be
a  limiting  factor.    Most of  the  genera  are well
distributed from < 12° to 35° C.
                               804: A preponderance of genera is found at   sul-
                            fate  levels in the  2 to 60  ppm range. Above this
                            there are  scattered records up to 480 ppm, with only
                            Psychomyiid sp. being above 480 ppm. Below 10 ppm
                            the records, as can be seen, are also rather sparse
                            (Table 13).
          Table 12. FREQUENCY OF OCCURRENCE OF CADDISFLY GENERA AT DIFFERENT
                             TEMPERATURE LEVELS (644 RECORDS)
Caddisfly
genera
Chimarra
Neureclipsis
Phylocentropus
Polycentropus
Psychomyiid sp.
C heuma top syche
Hydropsyche
Macronemum
Hydroptila
Athripsodes
Leptocella
Mystacides
Oecetis
Triaenodes
Pycnopsyche
Ptilostomus
Molanna
Helichopsyche
Brachycentrus
Lepidostoma
Totals
Temperature, °C
12
1
2



1
7
5
1
2
1



3

1



24
17

1
1
3
1
5
4
3

1
2

1

3
1

1
1
1
29
20

5
2
2
5
8
5
7
2
5
5

6
2
1
1


3
1
60
23
3
5
5
3
2
15
19
10
3
8
10
3
5
2
9
2
4
8
6
1
125
28
13
27
7
6
17
28
50
36
12
9
27
4
25
14
13

2

7
1
298
30

2


7
2
9
5
4
1
10

9
3






52
35 40

7

2

5
11
5

4
7

7
4



4


56
          Table 13. FREQUENCY OF OCCURRENCE OF CADDISFLY GENERA AT DIFFERENT
                                 SULFATE LEVELS (619 RECORDS)
Caddisfly
genera
Chimarra
Neureclipsis
Phylocentropus
Polycentropus
Psychomyiid sp.
Cheumatop syche
Hydropsyche
Macronemum
Hydroptila
Athripsodes
Leptocella
Mystacides
Oecetis
Triaenodes
Pycnopsyche
Ptilostomus
Molanna
Helichopsyche
Brachycentrus
Lepidostoma
Totals
1
1



1

1
1


1



1

1



7
10
10
18
7
3
6
17
29
32
7
15
16

13
6
8
1
3
1
9
4
205
30
4
16
6
8
11
22
28
8
15
5
23
8
21
7
8
2
4
5
2

203
Sulfate
60

11

4
4
14
22
16
1
7
11

11
5
11
1

4
5

127
concentrations
90 120

3
1
2

4
4
3

1
1

3
3
2





27
1
1



1
2



2


1






8
, ppm
240



3
1
3
5



2

2
2
2


1


21
480 960 1,500
1



2 1
1
5

4



2

2


3


20 1

-------
                               Environmental Requirements of Trichoptera
                                            125
   Turbidity:  The caddisfly larvae seem to be able to
tolerate turbidity levels up to 100 ppm (Table 14).
Above this they drop off slightly at 500 ppm (16 genera
present).   Between 501 and 1,000 ppm the  records
are fewer; only seven genera are present.  There does
not appear to be any difference between the case
makers and the net makers in response. One would
normally expect that the net makers, which are de-
pendent on  suspended material for their food supply,
would be more sensitive to high turbidities since the
silt load would tend to clog their food-gathering nets.

   BOD:   The caddisfly larvae (Table 15) are well
distributed  at levels up to 5.0 ppm.  The paucity of
            Table 14.  FREQUENCY OF OCCURRENCE OF CADDISFLY GENERA AT DIFFERENT
                                TURBIDITY LEVELS (667 RECORDS)
Caddisfly
genera
Chimarra
Neureclipsis
Phylo centropus
Polycentropus
Psychomyiid sp.
Cheumatopsyche
Hydropsyche
Macronemum
Hydroptila
Athripsodes
Leptocella
Mystacides
Oecetis
Triaenodes
Pycnopsyche
Ptilostomus
Molama
Hellchopsyche
Brachycentrus
Lepidostoma
Totals

10
5
4
5
5
7
12
18
9
3
4
7
3
7
3
7

5
6
6
1
117

25
4
11
1
5
8
13
23
14
10
5
12

13
7
7
2
2
6
2
1
146
Turbidity
50
5
11
7
3
7
19
20
18
4
7
18
5
14
11
7
2

1
3
1
163
levels,
100
2
16
1
6
11
13
29
17
7
7
14

15
3
8

1
1
5

156
ppm
500
1
8
1
1
1
7
13
10
3
5
11

6
2
4



1
1
75

1,000





1
2
2

2
1

1

1





10
          Table 15. FREQUENCY OF OCCURRENCE OF CADDISFLY GENERA AT  DIFFERENT
                       BIOCHEMICAL OXYGEN DEMAND LEVELS (581 RECORDS)
Caddisfly
genera
Chimarra
Neureclipsis
Phylo centropus
Polycentropus
Psychomyiid sp.
Cheumatopsyche
Hydropsyche
Macronemum
Hydroptila
Athripsodes
Leptocella
Mystacides
Oecetis
Triaenodes
Pycnopsyche
Ptilostomus
Molanna
Helichopsyche
Brachycentrus
Lepidostoma
Totals

0.1

4



4
6
4
1

4

3







28

0.5
2
10
2

8
4
14
8
4
4
5

4
3
7

2
2
2
2
83
BOD
1.0
8
15
6
6
5
21
30
26
4
15
19
2
16
9
13

3
9
5
1
213
levels,
5.0
6
15
6
7
5
21
30
16
11
8
20
6
20
11
10
3
2
3
4
1
205
ppm
10.0

1

1

3
5
2
1
2
1

1
1
2





20

20.0 40.0
1


4

4
4 1
4 1


4 1

4





4

28 4

-------
126
                       ENVIRONMENTAL REQUIREMENTS OF AQUATIC INSECTS
records at the low  end  is  ascribable to a lack of
streams with BOD so low. Above 5.0ppm the records
are more sparse, with only four genera above 20.0
ppm.   Cheumatopsyche  has been  recorded  in the
literature as  tolerant of organic load.  As can be seen
in Table 15, four genera, three of them net makers, were
found  at  higher  BOD levels  than  Cheumatopsyche.
   Cu  and Zn:   We have only one set of field data,
from  the North  Anna River  in  Virginia,  in which
tests  were  conducted for soluble  zinc and copper.
In this situation  we  found Chimarra  and Cheumato-
psyche at soluble zinc  concentrations of 0.02 ppm
and  soluble  copper  concentrations  of 0.056  ppm.
Macronemum andBrachycentrus were found at soluble
zinc  concentrations  of<0.004and soluble  copper
concentrations  of<0.020ppm.   Psychomyiid sp. was
present at soluble zinc levels of 0.006 ppm and copper
levels of 0.000,  dropped out  at zinc 0.02 ppm and
copper 0.056, and reappeared at zinc 0.014 ppm and
copper 0.036 ppm.

                 TOXICITY TESTS

   This is a  field in  which a great deal of work needs
to be  done.  We  need to know more of the effects of
the factors discussed under controlled conditions and
of the effects of  combinations of these factors.  As
far as insects are concerned, toxicity tests must be
interpreted  with  caution for the following reasons:
Difficulty in keeping specimens  alive; general lack
of  strong movement (compared with fish) and  the
consequent lack  of  mixing in  the solution; creation
of microclimates around each specimen; the plating
out effect of  herby metals, which increases local con-
centrations;  determination of the instar being tested;
and the  difficulty in rearing through several gen-
 erations to show  long-term sublethal effects.

   Table  16  shows the results of a series of toxicity
tests  conducted  by  Dr.  Benoit  at  the  Academy of
Natural Sciences.  The  specimens were  kept in the
lids of 2-pound butter dishes that  were placed in a
temperature-controlled  room.  The water used was a
modification  of Chu 14.   The Hydropsyche were H.
betteni and Hydropsyche (bifida group) spp.   I have
included the data on mayflies 'Stenonema rubrumMcD)
for the  purpose of comparison. The differences be-
tween the two genera in toleratingthe chemicals listed
are quite striking, the caddisfly larvae being far more
tolerant  than Stenonema.   The 9,000 ppm NaCl  is
equivalent to a Cl concentration of 5,400 ppm. Con-
verted to  salinity,  this  is 9,750 ppm  salinity - just
below the  lower limit of the polyhaline category of
Redeke (1922).
                    SUMMARY

   We can say that caddisfly larvae are tolerant of
a wide range of most of the chemical factors reported.
Cheumatopsyche and Hydropsyche have been reported
tolerant  of  a  wide range  of  chemical conditions,
particularly pollution.   This is borne out by the data
presented here.   Both were found at DO  values as
low as 1.0 ppm.  Cheumatopsyche was found in water
containing over 10 ppm BOD and Hydropsyche at over
20 ppm BOD.   In addition, both were  tolerant of high
turbidity,  SO^  concentrations over 240 ppm,  total
hardness over 2,500 ppm, and Cl concentrations over
2,500 ppm.   Other of  the genera  also proved to be
quite  tolerant. Chimarra was found in water contain-
ing over 2,500 ppm of  Cl, over 40  ppm of CO2, over
2,500 ppm  hardness,  and   over   20  ppm   BOD.
Macronemum and Leptocella were  found over a wide
range of most  of  the  chemical factors reported.  In
general  there  were  few differences in response
between the net  and web builders versus the  case-
making genera.  For  CO2, more case makers were
found at concentrations over 40 ppm; the net builders
were  more  common at high hardness values and low
PO4  concentrations.   At higher phosphate concen-
trations (over 1.0 ppm), the case makers were more
abundant, and at high BOD levels the net builders were
more common.   The records at these extremes are
so sparse that one must be careful not to exaggerate
the significance of these differences.
          Table 16. TOLERANCE OF HYDROPSYCHE AND STENONEMA TO VARIOUS CHEMICALS.
                               100 PERCENT SURVIVAL IN ALL CONTROLS
Chemical
NaCl
K2 Cr2 07 as Cr
KCN (as CN)
Phenol
Temp,
°F
68-72
68-72
68-72
68-72
Dil
Water
Soft
Soft
Soft
Soft
48-hr TLW ppm
Hydropsyche
9,000
280
2.0
30
Stenonema
2,500
3.5
0.5
14.5
                                             REFERENCES
 Betten, C. 1934.  The caddisflies or Trichoptera of
 New York State.  N.Y. State Mus. Bull. 292, 576 pp. ill.
 Hynes, H.   1960.   The biology of polluted waters.
 Liverpool University Press XIV, 202 pp.  ill.

 Lloyd,  J. T.  1921.  The biology of North American
 caddisfly larvae. Lloyd Library of Botany, Pharmacy
 and Materia Medica Bull.  21:1-24, ill.
 Redeke, H.  C.  1922.  Zur biologic der Niederland-
 ischen Brackwasser typen. Bijdr. Dierk.  22:329-335.

 Ross, H. H.  1949.  The  caddisflies or Trichoptera
 of Illinois.  Bull.  111. Nat. Hist. Surv. 23 art. 1:326 pp.
 ill.

-------
                  A SURVEY OF ENVIRONMENTAL REQUIREMENTS FOR THE MIDGE

                                        (Diptera: Tendipedidae)


                                          By LaVerne L. Curry*
                  INTRODUCTION

   A  discussion  of the  environmental requirements
of  many  organisms  will  include  habitats  ranging
from stock-watering  tanks to vernal ponds.  Like-
wise, the fauna  found in the variety of habitats is
diverse. Probably one of the most rewarding experi-
ences of the biologist is to glean general knowledge
from the samples  after the  organisms  have been
identified.

   There is a pressing  need today  for  information-
physical, chemical, biological-regarding  all phases
of aquatic life.  A deluge of wastes is entering waters,
and  the effects  upon the biomass  are  little known.
Many examples  can be  cited, but a case in point is
that of the Clear Lake  gnat in California  (Kipling,
1950; Lindquist  and Roth,  1950;  Walker, 1951).   In
the  treatment of this  lake,  the tendipedids  were
virtually  eliminated  during  the  first  season,  but
appeared again, resulting in additional treatment pro-
grams.  Cost of the original project was $42,000,  and
the cost for each retreatment program, even higher.

   Today biologists are investigating the plausibility
of applying  natural controls in conjunction with arti-
ficial methods.  For example, comparisons are being
made with the use of carp.  (Cyprinus carpio Linne,
goldfish (Carassius auratus Linne) , catfish (Icta-
lurus punctatus Rafinesque) , and  exotic fish, such as
Tilapia  mossambica Peters,  as predators on tendi-
pedids  (Bay and  Anderson, 1960).  Results of these
tests are being  compared  with the effectiveness of
larvicides.

   It  is apparent that the biologist must be aware of
environmental  limitations when  applying biological
controls.    In many  cases, however,  our  present
knowledge  is still incomplete regarding the problem
species itself.   The purpose of this paper is to pre-
sent physical, chemical,  and biological data regard-
ing the fresh-water tendipedid fauna.  Some of the
information  is  derived  from the  literature,  since
the data obtained from field  studies in Michigan fell
within the  arbitrary limits established in this paper.
                     HISTORY

   At present, little  is known of the ecological re-
quirements  of fresh water tendipedids. Considerable
effort has been expended to obtain data from occasion-
al studies. Early investigations were general, and data
pertaining to tendipedids were incidental to the overall
project,  whether it was in fisheries, lake systems,
or pollution (Hankinson,  1908;  Malloch,     1915;
Baker,  1918;  Richardson,  1928).   Later,  Brundin
(1949) investigated the relationship of tendipedids with
respect  to  lake  typology, and Thienemann  (1954)
recorded  considerable information  about tendipedids
throughout the world.

   In recent years,  the problem of tendipedid identifi-
cation  has  been given  much-needed attention.   A
revision   of the family  has been made by Townes
(1945)  and Johanns.en, et al. (1952).  Information  is
now  available  for  the biologist  of pollution  on the
Ethiopian and Australian fauna (Freeman, 1955, 1956,
1957, 1958,  1961).   With  the  continued interest  in
public  health problems by the World Health Organi-
zation, this information  will find an appropriate use.

   Problems in nomenclature  have posed a problem
for  water  pollution  biologists.    Since  investiga-
tions are carried on in different biogeographical
regions  and  two diametrically opposed  taxonomic
systems   are  used,  the  problem  is more  acute.
Additional keys have been published for many of the
immature  stages  and for adult  tendipedids  since
the work  of Johannsen (1937a,  1937b). These include
information on the  biology  of  the tendipedid species
in the  Philadelphia area (Roback, 1957) and Michigan
(Curry, 1958).

   The nomenclature employed in this paper is based
upon that of  Townes (1945)  and  Johannsen,  et al.
(1952).   For  convenience in using  European litera-
ture, a   synonymy   checklist   is  derived for the
Nearctic  forms  of the genus  Tendipes when known
(Table  1).    This list  is  based,  in part, upon the
nomenclature employed by Edwards (1929).
* Professor Biology, Head Dept. Biology, Central Michigan University, Mt. Pleasant, Michigan.
                                                    127

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128                    ENVIRONMENTAL REQUIREMENTS OF AQUATIC INSECTS


          Table 1.  SYNONYMY CHECKLIST OF EARLY EUROPEAN AND AMERICAN AUTHORS

   Allochironomus Kieffer = Tanytarsus (Stictochironomus) Kieffer
   amularis Macquart = riparius (Meigen,  Tandipes (T)
   anomalus Kieffer = riparius (Meigen), Tendipes (T)
   anonymous Williston, Chironomus = attenuatus (Walker), Tendipes (T)
   anthracinus?,  Tendipes = anthracinus  (Zetterstedt), Tendipes (T)
   anthracinus Zetterstedt, Chironomus = anthracinus (Zetterstedt), Tendipes (T)
   atritibia Malloch, Chironomus (C) = atritibia (Malloch), Tendipes (T)
   attenuatus Walker, Chironomus = attenuatus (Walker), Tendipes (T)
   bathophilus Kieffer, Chironomus = anthracinus (Zetterstedt,  Tendipes (T)
   brevitibialis (Goetghebuer), Chironomus = lobiger (Kieffer),  Tendipes (L)
   brevitibialis (Kieffer),  Chironomus = lobiger (Kieffer), Tendipes (L)
   brevitibialis (Zetterstedt), Chironomus = nervosus (Staeger), Tendipes (L)
   Brunieria Kieffer  = Tony tarsus (Stictochironomus) Kieffer
   brunneipennis  Johannsen, Chironomus = brunneipennis (Johannsen), Tendipes (E)
   californicus (Johannsen), Chironomus = californicus  (Johannsen), Tendipes (L)
   Camptochironomus Kieffer = Tendipes (Tendipes)  Meigen
   camptolabis Kieffer, Cladopelma = Harnischia (Cladopelma)  Kieffer
   cayugae Johannsen, Chironomus = attenuatus (Walker), Tendipes (T)
   Chironomus Meigen = Tendipes Meigen
   cingulatus Meigen, Chironomus = stigmaterus (Say), Tendipes (T)
   Cladopelma Kieffer = Harnischia (cladopelma)
   Cladotendipes  Lenz
   Clinochironomus  Kieffer =  Tendipes Meigen
   conformis Malloch, Chironomus = pilicornis (Fabricius), Tendipes (T)
   crassicaudatus Beyer?,Tendipes = crassicaudatus Malloch,  Tendipes (T)
   cristatus ? Fabricius, Chironomus = attenuatus (Walker) Tendipes (T)
   cristatus Fabricius?, Chironomus = attenuatus (Walker) Tendipes (T)
   curtibarba  Kieffer = riparius (Meigen), Tendipes (T)
   curtiforcepsK.ief.ier =  riparius (Meigen), Tendipes (T)
   decorus Johannsen, Chironomus - attenuatus (Walker) Tendipes (T)
   decorus Johannsen, Chironomus (C) = attenuatus (Walker), Tendipes (T)
   decorus Johannsen, Tendipes = attenuatus (Walker) Tendipes (T)
   decumbens Malloch, Chironomus (C) = decumbens (Malloch,  Tendipes (T)
   dichromocerus Kieffer ? = riparius (Meigen), Tendipes (T)
   dzstozs Kieffer ? - riparius  (Meigen), Tendipes (T)
   distinguendus Kieffer, Chironomus = attenuatus  (Walker), Tendipes  (T)
   dolens Walker?,Chironomus (C)  = pilicornis (Fabricius), Tendipes  (T)
   Dolichopelma Kieffer = Lauterborniella Bause
   dorsalis  (? not Meigen),Chironomus = riparius (Meigen), Tendipes (T)
   dorsalis Meigen,  Chironomus = dorsalis (Meigen), Tendipes (E)
   dorsalis Meigen, Chironomus = riparius (Meigen), Tendipes (T)
   dorsalis Meigen, Tendipes = dorsalis (Meigen)  Tendipes (E)
   dux Johannsen, Chironomus = dux (Johannsen), Tendipes (K)
   dux Johannsen, Cladopelma = dux (Johannsen, Tendipes (K)
   falciformis Kiefier, Chironomus - nervosus  (Staeger),Tendipes (L)
   fasciventris Malloch, Chironomus = staegeri (Lundbeck) Tendipes (T)
   fasciventris Malloch?, Chironomus (C) = staegeri (Lundbeck),  Tendipes (T)
   ferrugineo-vittatus Zetterstedt, Chironomus = ferrugineo-vittatus (Zetterstedt), Tendipes (T)
   ferrugineo-vittatus Johannsen, Chironomus = plumosus (Linnaeus),  Tendipes (T)
   fulvipilus Rempel, Chironomus = fulvipilus (Rempel), Tendipes?  (T)
   fumidus (Johannsen),Chironomus =fumidus (Johannsen), Tendipes (L)
   fumidus Johannsen, Chironomus (L) = neomodestus  (Malloch),  Tendipes (L)
   futilis  (Walker), Chironomus -nervosus (Staeger), Tendipes (L)
   glaucurus  Wiedemann, C/wrowo»ms = stigmaterus (Say), Tendipes (T)
   goetghebueri Kieffer, Chironomus = nervosus (Staeger), Tendipes (L)
   Goetghebueria  Kieffer = Tenytarsus Wulp
   gregarius  Kieffer,Chironomus = riparius (Meigen), Tendipes (T)
   grisescens  Goetghebuer,Chironomus = riparius (Meigen), Tendipes (T)
   helochares Kieffer, Chironomus = riparius (Meigen), Tendipes (T)
   hyperboreus Staeger,Chironomus = anthracinus (Zetterstedt), Tendipes (T)
   hyperboreus Staeger, Chironomus = hyperboreus (Staeger), Tendipes (T)
   hyperboreus Staeger, Chironomus (C) = anthracinus (Zetterstedt), Tendipes (T)
   hyperboreus Staeger, Chironomus (C) = hyperboreus (Staeger),  Tendipes  (T)
   hyperboreus Staeger, Tendipes (T) = hyperboreus (Staeger), Tendipes (T)
   hyperboreus variety meridionalis Johannsen,  Chironomus =  anthracinus (Zetterstedt), Tendipes (T)

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                         A Survey of Environmental  Requirements for the Midge                     129


 Table 1.  SYNONYMY CHECKLIST OF  EARLY EUROPEAN AND AMERICAN AUTHORS (CONTINUED)

 hyperboreus variety Staeger, Chironomus = staegeri (Lundbeck), Tendipes (T)
 imperatorVfalley, Chironomus = plumosus (Linnaeus), Tendipes (T)
 incognitus (Malloch), Chironomus = fumidus (Johannsen), Tendipes (L)
 indistwctus Malloch, Chironomus -nervosus  (Staeger), Tendipes (L)
 indivisus Kieffer =  riparius (Meigen), Tendipes (T)
 interruptus Kieffer = riparius (Meigen), Tendipes (T)
 iththybrota Kieffer = riparius (Meigen), Tendipes (T)
 Limnotendipes Lenz = Tendipes (Limnochironomus) Kieffer
 lobiger Kieffer Chironomus - lobiger (Kieffer), Tendipes (L)
 lobiger variety miriforceps (Kieffer), Tendipes (L)  - lobiger  (Kieffer), Tendipes (L)
 longipes Staeger, Chironomus = dorsalis (Meigen), Tendipes (E)
 lucifer Johannsen, Chironomus = nervosus (Staeger), Tendipes (L)
 lucifer Johannsen, Chironomus (C) (Limnochironomus group) = nervosus (Staeger), Tendipes (L)
 maturus Johannsen}  Chironomus = attenuatus (Walker), Tendipes (T)
 meridionalis Johannsen?, Chironomus = anthracinus (Zetterstedt),Tendipes (T)
 militaris Johannsen, Chironomus = riparius (Meigen), Tendipes (T)
 miriforcips (Kieffer), Chironomus = lobiger (Kieffer), Tendipes (T)
 miriforcips (Goetghebuer), Chironomus = lobiger (Kieiier),Tendipes (T)
 modestus Say, Chironomus (Limnochironomus) = modestus (Say), Tendipes (L)
 modestus (Say), Cladopelma = modestus (Say), Tendipes (L)
 modestus variety a,  Chironomus = nervosus (Staeger), Tendipes (L)
 moerens Walker"?, Chironomus (C) = pilicornis (Fabricius), Tendipes (T)
 neomodestus Malloch, Chironomus = neomodestus (Malloch),  Tendipes (T)
 nervosus Staeger, Chironomus - nervosus (Staeger), Tendipes (T)
 nervosus Staeger, Chironomus (L) = nervosus  (Staeger), Tendipes (L)
 niger Meigen, Chironomus (C) = pilicornis (Fabricius), Tendipes (T)
 niveipemis Fabricius, Chironomus = pilicornis (Fabricius),   Tendipes (T)
 obscuratus Malloch, Chironomus = dux (Johannsen), Tendipes (K)
 paganus Meigen, Chironomus =paganus (Meigen), Tendipes (E)
 paganus Meigen, Tendipes (Phytotendipes) = paganus (Meigen), Tendipes (E)
 Phy to Chironomus Kieffer = Glyptotendipes (Glyptodentipes)'Kieiier
 Phytotendipes Goetghebuer = Glyptotendipes (Phytotendipes) Goetghebuer
 pilicornis  ?, Chironomus (C) -pilicornis (Fabricius), Tendipes (T)
 pilicornis  Fabricius, Chironomus = pilicornis  (Fabricius), Tendipes (T)
 plumosa Linnaeus, Tipula = plumosus (Linnaeus), Tendipes (T)
 plumosus Linnaeus, Chironomus = plumosus (Linnaeus), Tendipes (T)
 plumosus Linnaeus, Tendipes = plumosus (Linnaeus), Tendipes (T)
 plumosus variety ferrugineo-vittatus Johannsen = ferrugineo -vittatus (Zetterstedt), Tendipes (T)
plumosus variety ferrugineo-vittatus Johannsen, Chironomus = plumosus (Linnaeus), Tendipes (T)
Polaris Kirby?,Chironomus = hyperboreus (Staeger), Tendipes (T)
polaris Kirby, Tendipes (T) = hyperboreus (Staeger), Tendipes (T)
 Prochironomus Kieffer = Tany tarsus Wulp
 Pro tany tarsus Kieffer = Tany tarsus (genus)
 restrictus  Kieffer? = riparius (Meigen),  Tendipes (T)
rhyparobius Kieffer = riparius (Meigen), Tendipes (T)
 riparius Kieffer?, Tendipes = riparius (Meigen), Tendipes (T)
riparius Kruseman nee. Meigen = riparius (Meigen), Tendipes (T)
riparius Meigen, Chironomus = riparius (Meigen), Tendipes (T)
riparius Meigen, Chironomus = staegeri (Lundbeck), Tendipes (T)
saxonicus Kieffer = riparius (Meigen), Tendipes (T)
 serus Malloch, Chironomus = riparius (Meigen), Tendipes (T)
 serus ?  Johannsen, Chironomus (C) = riparius  (Meigen), Tendipes (T)
similis  Johannsen, Chironomus = attenuatus (Walker), Tendipes (T)
staegeri Lundbeck,Chironomus = staegeri (Lundbeck), Tendipes (T)
staegeri Lundbeck?, Chironomus (C) = staegeri (Lundbeck), Tendipes (T)
staegeri ? Lundbeck,  Chironomus = atritibia (Malloch), Tendipes (T)
Stictotendipes  Lenz =  Tendipes (Tendipes) Meigen
stigmaterus Say, Chironomus = stigmaterus (Say), Tendipes (T)
sttgmaterus ? Say, Chironomus = stigmaterus (Say),  Tendipes  (T)
stricticornis Kieffer = riparius (Meigen), Tendipes (T)
subacutus Kieffer = riparius (Meigen), Tendipes (T)
subproductus  Kieffer = riparius (Meigen), Tendipes (T)
subrectus  Kieffer = riparius (Meigen)  Tendipes (T)
subriparius Kieffer = riparius (Meigen),  Tendipes (T)
Syntendipes Lenz = Tendipes (Tendipes) Meigen

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 130
ENVIRONMENTAL REQUIREMENTS OF .AQUATIC INSECTS
     Table 1. SYNONYMY CHECKLIST OF EARLY EUROPEAN AND AMERICAN AUTHORS (CONTINUED)

   tenellus Zetterstedt, Chironomus = neomodestus (Malloch), Tendipes (L)
   teutons Fabricius, Chironomus = plumosus (Linnaeus), Tendipes (T)
   tentans Fabricius, Chironomus = tentans (Fabricius),  Tendipes (T)
   teutons Kruseman?, Tendipes (CamptoChironomus) = tentans (Fabricius), Tendipes (T)
   tentans varietypallidivittatus Malloch, Chironomus =  tentans (Fabricius), Tendipes (T)
   thummi Kieffer, Chironomus = riparius (Meigen), Tendipes (T)
   tkummi Kieffer, Tendipes = riparius (Meigen), Tendipes (T)
   tristis Wiedemann, Chironomus  (C) = pilicornis (Fabricius), Tendipes (T)
   tritomus  Kieffer, Chironomus  =  nervosus (Staeger), Tendipes (L)
   tuxis Curran, Chironomus ~ tuxis  (Curran), Tendipes  (T)
   tuxis Curran?, Chironomus (C) = tuxis  (Curran), Tendipes (T)
   ?tuxis Curran, Tendipes (T) = tuxis (Curran), Tendipes (T)
   utahensis Malloch, Chironomus = utahensis (Malloch), Tendipes (T)
   viridicollis Wulp Chironomus  -  atroviridis Townes, Tendipes (C)
   viridicollisWulp, ?Chironomus = atroviridis Townes,  Tendipes (C)
   viridicollis ? Wulp, Chironomus - riparius (Meigen),  Tendipes (T)
   (near) viridicollis Wulp, Chironomus = atroviridis Townes, Tendipes (C)
   "viridicollis" Wulp,Chironomus (E) = atroviridis Townes, Tendipes (C)
   viridipes  Macquart = riparius  (Meigen), Tendipes (T)
   The following names have no synonymy.
          aethiops  Townes, Tendipes (L)
          atrella Townes, Tendipes (T)
          biseta Townes, Tendipes (T)
          bo torus Townes, Tendipes (L)
          cams Townes, Tendipes  (T)
          Chaetolabis Townes
          chelonia  Townes, Tendipes (E)
          Einfeldia Kieffer
          Kiefferulus Goetghebuer
          leucoscelis, Townes,  Tendipes (L)
          milleri  Townes, Tendipes (L)
          ochreatus Townes, Tendipes (C)
          pungens  Townes, Tendipes (T)
          tendipediformis Goetghebuer, Tendipes (K)
          tuberculatus Townes, Tendipes  (T)
        ENVIRONMENTAL REQUIREMENTS
   Evidence has been introduced describing types of
environmental selectionby the f resh-watertendipedids.
These  data have  been  applied in developing a lake
"typology" (Brundin, 1949;  Thienemann, 1954)thathas
found some application in the United States.  Richard-
son (1928) proposed a classification, based on tolerance
to pollution,  of  tendipedids  found  in  the  middle
Illinois River.  Later work  by Paine andGaufin (1956)
questioned the  use of tendipedid  larvae as indicator
organisms because of their adaptability to environ-
mental conditions.

   This adaptability is illustrated by their morphology
and physiology.  The larval adaptations were used by
Leathers (1922) to  classify  the members of the family
into  six groups (1) burrowers, (2) attached tubes, (3)
tubes of mud, (4) leaf-eating,  (5) alga-eating,  and (6)
free-living larvae.  With respect to their physiology,
tendipeded larvae have been collected in habitats rang-
ing from hot springs  (Brues, 1928) to salt-water rock
pools (Palmen, 1956; Lindeberg,  1958).  In addition,
field  and laboratory work has  been conducted on
selective larvicides, based on  tendipedid  biology, in
Wisconsin  and New  York  (Dicke, 1957;  Bay, 1960).
It is  not unusual then to find the larval forms existing
in a great variety of environmental conditions.
                                 The field work conducted in the Central Michigan
                              area did not involve grossly polluted streams. In an
                              attempt to determine the maximum-minimum require-
                              ments of tendipedids, the  literature  was used exten-
                              sively.  Unfortunately, only a small portion of it was
                              useful  because the forms were not classified as to
                              genus or species.  The maximum-minimum levels of
                              the environmental conditions found in this study are as
                              follows:

                                 Temperature.   In general, the temperature  re-
                              quirements  of the tendipedids are within  the limits
                              established by the Aquatic Life Advisory Committee
                              (1956)  in that "aquatic  organisms in the  temperate
                              zone are adapted to seasonal fluctuations of tem-
                              perature between 0° and  32°C (32°  to about  90°F)"
                              (Table 2). One species,Pelopia, is able  to live under
                              an extreme temperature of 39.59°C (103°F). The upper
                              limit, in general,  for the majority of species in the
                              subfamilies  Pelopiinae,  Diamesinae, Hydrobaeninae
                              and Tendipedinae is between 30 to33°C (86to 93.2°F).
                              Larvae oiCricotopustrifasciatus (Panzer),C. bicinctus
                              (Meigen), as  well  as representatives of Pentaneura
                              and Cryptochironomus are reported in waters having
                              temperatures of 34°C (93.2°F).  Immature forms of
                              Pentaneura monilis  (Linnaeus) have been found in
                              waters  having  temperatures  of  35QC  (95°F).   In

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                  A Survey of Environmental Requirements for the Midge
131
Table 2.  RANGES OF ENVIRONMENTAL FACTORS FOR FRESH-WATER TENDIPEDID SPECIES
Species
Pelopiinae
Pentaneura carnea (Fabricius)
Pentaneura illinoesis (Malloch)
Pentaneura melanops (Wiedemann)
Pentaneura monilis (Linne)
Pentaneura vitellina (Kieffer)
Penaneura sp.
Anatopynia dyari (Coquillett)
Anatopynia sp.
Pelopia punctipennis (Meigen)
Pelopia stellata (Coquillett)
Pelopia vilipennis (Kieffer)
Pelopia sp.
Procladius bellus Loew
Procladius choreus Meigen
Procladius culcifarmis (Linne)
Procladius sp.


Clinotanypus caliginosus (Johannsen)
Coelotanypus concinnus (Coquillett)
Diamesinae
Prodiamesa olivacea (Meigen)
Syndiamesa
Diamesa nivoriunda Fitch
Hydrobaeninae
Corynoneura scutellata (Winnertz)
Corynoneura sp.

Cricotopus absurdus (Johannsen)
Cricotopus bicinctus (Meigen)

Cricotopus exilis (Johannsen)
Cricotopus politus (Coquillett)
Cricotopus tricinctus (Meigen)
Cricotopus trifasciatus (Panzer)

Cricotopus sp.
Hydrobaenus sp.

Tendipedinae
Calopsectra dives (Johannsen)
Calopsectra johannseni (Bause)
Calopsectra neaflavella (Malloch)
Calopsectra nigripilus (Johannsen)
Calopsectra sp.

Pseudochironomus richardsoni
(Malloch)
Pseudochironomus sp.
Lauterborniella gracilenta
Lauterborniella varipennis
(Coquillett)
Microtendipes pedellus (DeGeer)
Microtendipes sp.
Paratendipes albimanus (Meigen)

Temperature,
min max

0.0
0.0
0.0
4.4
0.0
4.4
0.0

0.0
0.0
4.4

4.4
4.4
0.0
0.0


0.0
0.0



0.0

0.0
0.0

0.0
0.0

0.0
0.0
0.0
0.0


0.0


4.4
0.0
0.0
0.0
0.0

0.0

4.4

4.4

0.0
7.8
0.0


32.8
32.8
32.8
35.0
32.8
34.0
32.8

32.8
32.8
30.0
39.5
26.7
26.7
32.8
30.0


32.8
32.8



32.8

32.8
32.8

32.8
34.0

32.8
32.8
32.8
34.0

38.8
34.0


26.7
32.8
32.0
32.8
30.0

32.8

30.0

26.7

32.8

32.8

pH,
min max

6.0 to 9.1
7.2 to 9.1
7.2 to 9.1
6.0 to 8.0
7.2 to 9.1
5.2 to 8.5
6.0 to 9.1

7.2 to 9.1
7.2 to 9.1
6.8 to 8.5
8.1
7.0 to 8.5
7.0 to 8.5
6.0 to 9.1
6.8 to 9.1


7.2 to 9.1
7.2 to 9.1

4.4 to 7.8

7.2 to 9.1

7.2 to 9.1
4.4 to 9.1

7.2 to 9.1
6.0 to 9.1

7.2 to 9.1
7.2 to 9.1
7.2 to 9.1
6.0 to 9.1

9.6
6.8 to 9.1


7.0 to 8.5
7.2 to 9.1
7.2 to 9.1
7.2 to 9.1
6.8 to 9.1

7.2 to 9.1

6.8 to 8.5
4.4 to 7.8
6.0 to 8.5

6.0 to 9.1

5.0 to 9.1

DO,
ml/per CO2>
liter, ppm
min max

1.0
1.0
1.0
46.0
1.0

1.0

1.0
1.0
0.5 61.0

0.0 46.0
0.0 46.0
1.0
1.0 61.0


1.0
1.0



1.0

1.0
1.0

1.0
1.0

1.0
1.0
1.0
1.0


61.0


46.0
1.0
1.0
1.0
61.0



61.0

46.0

1.0 46.0

1.0 46.0

Authors

Paine (1956), Roback (1957)
Paine (1956)
Paine (1956)
Brues (1922), Roback (1957)
Paine (1956)
Jones (1948), Wurtz (1960)
Paine (1956), Roback (1957)
Jones (1949)
Paine (1956)
Guyer (1956), Paine (1956)

Brues (1928)
Guyer (1956)

Paine (1956), Roback (1957)
Dicke (1957), Jones (1949),
Lindeberg (1958), Paine (1956),
Teter (1960)
Paine (1956)
Paine (1956)

Jones (1948)

Paine (1956)

Paine (1956)
Jones (1948), Paine (1956),
Lindeberg (1958)
Paine (1956)
Baker (1918), Roback (1957),
Paine (1956, Wurtz (1960)
Paine (1956)
Paine (1956)
Paine (1956)
Paine (1956), Roback (1957),
Wurtz (1960)
Brues (1928), Jones (1948) (1949)
Brues (1928), Paine (1956),
Jones (1948) (1949)

Teter (1960)
Paine (1956)
Paine (1956)
Paine (1956)
Dicke (1957), Paine (1956),
Teter (1960)
Paine (1956)


Jones (1948)


Paine (1956), Roback (1957)
Jones (1949)
Lindeberg (1958), Paine (1956),
Roback (1957)

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132
ENVIRONMENTAL REQUIREMENTS OF AQUATIC INSECTS
Table 2.  RANGES OF ENVIRONMENTAL FACTORS FOR FRESH-WATER TENDIPEDID SPECIES (CONTINUED)
Species
Tendipedinae (Continued)
Paratendipes sp.
Polypedilum fallax (Johannsen)
Polypedilum halterale (Coquillett)
Polypedilum illinoense (Malloch)

Polypedilum nubeculosum (Meigen)
Polypedilum simulans Townes
Polypedilum sp.
Tanytarsus devinctus (Say)
Tany tarsus jucundus (Walker)
Tanytarsus nigr icons (Johannsen)
Tanytarsus varius Townes
Tanytarsus sp.
Xenochironomus scapula Townes
Cryptochironomus blarina Townes
Cryptochironomus digitatus
(Malloch)
Cryptochironomus fulvus (Johannsen)

Tendipes anthracinus (Zetterstedt)
Tendipes atroviridis Townes
Tendipes attenuatus (Walker)


Tendipes dux (Johannsen)
Tendipes fumidus (Johannsen)
Tendipes milleri Townes
Tendipes modes tus (Say)
Tendipes neomodestus (Malloch)
Tendipes nervosus (Staeger)
Tendipes ochreatus Townes
Tendipes paganus (Meigen)
Tendipes plumosus (Linne)
Tendipes riparius (Meigen)

Tendipes staegeri (Lundbeck)
Tendipes tendipediformis
(Goetghebuer)
Tendipes tentans (Fabricius)

Tendipes tuxis (Curran)
Tendipes sp.
Glyptotendipes barbipes (Staeger)
Glyptotendipes lobiferus (Say)
Glyptotendipes paripes (Edwards)
Glyptotendipes sp.

Harnischia tenuicaudata (Malloch)
Temperature,
min max


0.0
4.4
0.0

4.4
4.4
4.4
4.4
4.4
0.0
0.0

0.0
4.4
3.0

0.0


4.4
0.0


0.0
4.4
4.4
4.4
0.0
4.4
4.4
4.4
3.0
0.0

4.4
4.4

4.4

4.4


0.0
4.4
0.0

4.4

38.7
32.8
30.0
32.8

26.7
40.0
30.0
26.7
26.7
32.8
32.8

32.8
26.7
30.0

32.8


30.0
32.8


32.0
26.7
26.7
26.7
32.8
30.0
30.0
27.0
30.0
32.8

30.0
30.0

35.0

27.0


32.8
27.0
32.8

30.0
pH,
min max

8.1
6.0 to 9.1
5.0 to 8.5
4.0 to 9.1

7.0 to 8.5
6.8 to 8.5
6.8 to 8.5
7.0 to 8.5
4.0 to 8.5
6.0 to 9.0
7.2 to 9.1

7.0 to 9.1
7.0 to 8.5
8.8

4.0 to 9.1


6.8 to 8.5
4.0 to 9.1


6.8 to 9.1
5.0 to 9.0
7.0 to 8.5
5.0 to 9.0
7.0 to 9.1
6.9 to 8.5
6.8 to 8.5
7.0 to 8.5
6.8 to 8.8
5.0 to 9.1

6.0 to 8.5
6.8 to 8.5

6.8 to 8.5

7.0 to 8.5


7.0 to 9.1
5.0 to 8.5
7.0 to 9.1

6.0 to 8.5
DO, C02,
ml/liter ppm
min max


1.0
61.0
1.0

46.0
61.0
61.0
46.0
46.0
1.0 61.0
1.0

1.0
46.0


1.0 46.0


61.0
61.0


1.0 61.0
46.0
46.0
46.0
1.0 46.0
61.0
61.0
46.0
61.0
61.0

0.0 61.0
0.0 61.0

0.0 61.0

46.0


1.0 46.0
46.0
1.0 46.0

61.0
Authors

Brues (1928)
Paine (1956, Roback (1957)
Roback (1957)
Paine (1956), Roback (1957),
Wurtz (1960)
Palmen (1956)
Guyer (1956)
Teter (1960)
Paine (1956), Roback (1957)
Roback (1957)
Paine (1956), Roback (1957)
Paine (1956)
Jones (1949)
Paine (1956)
Curry (1958)
Curry (1958), Guyer (1956),
Lindeberg (1958), Tebo (1955)
Curry (1958), Paine (1956),
Roback (1957)
Lindeberg (1958)
Teter (1960), Roback (1957)
Dicke (1957), Paine (1956),
Lindeberg (1958), Palmen
(1956)
Paine (1956)
Roback (1957)
Roback (1957)
Roback (1957)
Paine (1956), Roback (1957)
Guyer (1956), Palmen (1956)


Dicke (1957)
Paine (1956), Roback (1957),
Wurtz (1960)
Roback (1957)


Brues (1928), (Lindeberg
(1958)

Jones (1949)
Lindeberg (1958)
Paine (1956)
Guyer (1956), Warnhoff (1957)
Dicke (1957), Paine (1956),
Wurtz (1960)

 addition, larvae of the genera of Pelopia, Cricotopus,
 and Parantendipes have been found in  waters having
 temperatures of 38° to 39.5°C (100° to 103°F) (Brues,
 1928;  Jones,  1948,  1949;  Paine  and  Gaufin,  1956;
 Roback 1957; and Wurtz, 1960). The minimal environ-
 mental temperature reported for larval habitats is at
 or near 0°C.

   Hydrogen ion  concentration.  Many stream forms
 are  able to endure a pH range of 6.0 to 8.0 or higher
                               (Table 2).  Representatives of the genera Pentaneura,
                               Anatopynia, Pelopia, Procladius, Clinotanypus,Diam-
                               esa, Corymoneura,  Cricotopus, and Hydrobaenus have
                               been  collected in  habitats  having a pH 9.1 (Jones,
                               1948; Paine and Gaufin, 1956; Lindeberg, 1958; Wurtz,
                               I960).   Several  members  of  the Calopsectrini  are
                               also  reported  to  inhabit waters  having a pH 9.1.
                               Many  members of  the tribe Tendipedini have been
                               found in waters having hydrogen ion concentrations of
                               this level.  Representative genera for these forms are

-------
                           A Survey of Environmental Requirements for the Midge
                                              133
Pseudochironomus,  Microtendipes,    Paratendipes,
Polypedilum,  Tanytarsus, Tendipes, and Glyptoten-
dipes.

   The  species  Prodiamesa olivacea  (Meigen),  a
stream form, has been found inhabiting water having
a pH 4.4  (Jones, 1948).  The species Lauterborniella
gracilenta, Polypedilum illinoense  (Malloch), Tany-
tarsus jucundus (Walker),Crypto chilenta, Polypedilum
illinoense  (Malloch), Tanytarsus jucundus (Walker),
Cryptochironomus fulvus (Johannsen), and Tendipes
attenuatus (Walker)  [-Tendipes decorus (Johannsenfj
are reported from waters having a pH 4.0.

   Dissolved oxygen.  Frequently this is listed as a
limiting factor in a given environment.  A considera-
tion  of this ecological requirement should also take
into  account  factors such as temperature, pollution,
and metabolic activity of the organism.

   It  appears that very  few  tendipedids are able to
withstand prolonged anaerobic  conditions imposed by
some lakes  and streams (Table 2).  Additional in-
formation  is  required through the use of bioassays
(Aquatic  Advisory  Committee,  1956).   Species of
Pentaneura,  Pelopia,   Clinotanypus,  Coelotanypus,
Corynoneura,  and Cricotopus  can,  however, endure
a dissolved-oxygen  content of  1.1 cm ^ per liter.  In
Michigan, Pelopia vilipennis  Kieffer was  found in-
habiting a hydrosol  where the  oxygen of the super-
imposed water was 0.5 cm3 per liter.

   Many species of the Tendipedinae are also found to
inhabit  waters with low dissolved-oxygen content.
These forms are found in all the major genera.  Only
forms such   as  Tendipes tentans  (Fabricius);  T.
steepen (Lundbeck);T. riparius (Meigen); T.plumosus
(L);  and T. attenuatus are, however, reported inhabit-
ing the anaerobic region  of lakes and streams. Studies
on  populations of two tendipedid forms in Michigan
lakes indicate further that the mortality rate is high
for the  species  found there.  This mortality may run
as  much  as 50  percent.    The greatest mortality
apparently is  in  the first or second instars of larval
development.
   Carbon dioxide.   Very few species of the  sub-
families  Pelopiinae,  Diamesinae, or Hydrobaeninae
are  reported  inhabiting waters where  high  concen-
trations of carbon dioxide are found (Table 2).  Larvae
of Pentaneura  monilis, P. vilipennis, Pelopia bellus
Loew,  P.  choreus Meigen, and a  species of Hydro -
baenus have been found in waters having 46 to  61 ppm
C02.
   Many species of the subfamily Tendipedinae appear
to inhabit  hydrosols with superimposed waters having
a high concentration of carbon dioxide. The most con-
spicuous forms are those of the genus Tendipes.  This
genus appears to have the majority of forms adapted
in living under these environmental conditions.

   Ionic concentration.  Very little has been recorded
for a  comparative study of  tolerance  to ionic  con-
centrations such  as  Ca++,  PO4=, 864=,  and trace
elements  (Table  3).   The comparative physiological
resistance to chloride  ions illustrates, however, a
physiological adaptability attained by a few species to
salt water. Palmen (1956) and Lindeberg (1958) have
reported  the Procladius sp.,  Corynoneura sp, Micro-
tendipes  pedellus, Paratendipes albimanus (Meigen),
Polypedilum halterale  (Coquillett),  P. nubeculosum
(Meigen),  Tendipes anthracinus (Zetterstedt), T. at-
tenuatus,  T. nervosus (Staeger), and T. tentans inhabit
brackish  water.   For a better understanding of the
adaptability of the organisms,  bioassay tests should
be run on  representative larvae of the various genera^
       Table 3. RANGES OF ENVIRONMENTAL FACTORS FOR FRESH-WATER TENDIPEDID SPECIES
Species
Pelopiinae
Pentaneura carnae
(Fabricius)
Pentaneura illinoensis
(Malloch)
Pentaneura melanops
(Weidemann)
Pentaneura monilis
(Linne)
Pentaneura vitellina
(Kieffer)
Pentaneura sp.
Anatopynia dyari
(Coquillett)
Anatopynia sp.
Pelopia punctipennis
(Meigen)
Pelopia stellata
(Coquillett)
Pelopia vilipennis
(Kieffer)
P04=,
ppm,
total
max

26.2

26.2

26.2



26.2


26.2


26.2
26.2



Ca++,
ppm,
max











25.8


22.0





Mg++,
ppm,
max











5.0


4.0





Fe+++,
ppm,
max











tra


0.0





cr,
ppm,
max











8.8


8.5





S04=,
ppm,
max











9.0


1.0





N03-,
ppm,
total
max

43.0

43.0

43.0



43.0


43.0


43.0
43.0



co3=,
ppm,
max

310

310

310



310


310


310
310



BOD,
max



82.0

82.0



82.0

3.04
82.0


82.0
82.0



Authors

Paine (1956),Roback (1957

Paine (1956)

Paine (1956)

Brues (1922), Roback (1957

Paine (1956)

Jones (1948),Wurtz (1960)
Paine (1956), Roback (1957

Jones (1949)
Paine (1956)
Guyer (1956), Paine (1956)




-------
134
ENVIRONMENTAL REQUIREMENTS OF AQUATIC INSECTS
Table 3. RANGES OF ENVIRONMENTAL FACTORS FOR FRESH-WATER TENDIPEDID SPECIES (CONTINUED)
Species
Pelopiinae (continued)
Pelopia sp.
Procladius bellus Loew
P04=,
ppm,
total
max



Procladius choreus Meigen
Procladius culciformis
(Linne)
Procladius sp.


Clinotanypus caligino-
sus (Johannsen)
Coelotanypus concinnus
(Coquillett)
Diamesinae
Prodiamesa olivacea
(Meigen)
Syndiamesa sp.
Diamesa nivoriunda
Fitch
Hydrobaininae
Corynoneura scutellata
(Winnertz)
Corynoneura sp.

Cricotopus absurdus
(Johannsen)
Cricotopus bicinctus
(Meigen)

Cricotopus exilis
(Johannsen)
Cricotopus politus
(Coquillett)
Cricotopus tricinctus
(Meigen)
Cricotopus trifasciatus
(Panzer)
Cricotopus sp.

Hydrobaenus sp.


Tendipedinae
Calopsectra dives
(Johannsen)
Calopsectra johannseni
(Bause)
Calopsectra neoflavella
(Malloch)
Calopsectra nigripilus
(Johannsen)
Calopsectra sp.


26.2
26.2


26.2

26.2






26.2

26.2



26.2

26.2


26.2

26.2

26.2

26.2









26.2

26.2

26.2

26.2

Pseudochironomus rich- 26.2
ardsoni (Malloch)
Pseudochironomus sp.


Ca++,
ppm,
max






22.0








23.0
22.0





23.0














25.8

25.8
















Mg++,
ppm,
max






4.0








4.5
4.0





4.5














5.0

5.0
















Fe+++,
ppm,
max






0.0








0.0
0.0





0.0














0.0

0.0
















cr,
ppm,
max






6.0








12.0
8.5





t














12.0

12.0
















S04 ,
ppm,
max






1.0








tr
1.0





tr














tr

1.0
















N03-,
ppm,
total
max





43.0
43.0


43.0

43.0






43.0

43.0

43.0

43.0

43.0


43.0

43.0

43.0

43.0



43.0





43.0

43.0

43.0

43.0

43.0


co3=,
PPm,
max





310
310


310

310






310

310

310

310

310


310

310

310

310



310





310

310

310

310

310


BOD,
max





82.0
82.0


82.0

82.0






82.0

82.0

82.0

82.0

82.0


82.0

82.0

82.0

82.0

3.04

82.0





82.0

82.0

82.0

82.0

82.0


Authors

Brues (1928)
Guyer (1956)


Paine (1956),Roback (1957)
Dicke (1957),Jones (1949),
Lindeberg (1958), Paine
(1956) Teter (1960)
Paine (1956)

Paine (1956)



Jones (1948)


Paine (1956)

Paine (1956)

Jones (1948), Paine (1956),
Lindeberg (1958)
Paine (1956)

Baker (1918), Roback
(1957), Paine (1956),
Wurtz (1960)
Paine (1956)

Paine (1956)

Paine (1956)

Paine (1956), Roback
(1957), Wurtz (1960)
Brues (1928), Jones
(1948) (1949)
Brues (1928), Paine
(1956), Jones (1948)
(1949)

Teter (1960)

Paine (1956)

Paine (1956)

Paine (1956)

Dicke (1957), Paine
(1956), Teter (1960)
Paine (1956)



-------
                       A Survey of Environmental Requirements for the Midge
135
Table 3.  RANGES OF ENVIRONMENTAL FACTORS FOR FRESH-WATER TENDIPEDID SPECIES (CONTINUED)
Species
Tendipedinae (continued)
P04=,
ppm,
total
max

Lauterborniella gracilenta
Lauterborniella varipennis
(Coquillett)
Micro tendipes pedellus
(DeGeer)
Micro tendipes sp.
Paratendipes albimanus
(Meigen)
Paratendipes sp.
Polypedilum fallax
(Johannsen)
Polypedilum halterale
(Coquillett)
Polypedilum illinoense
(Malloch)
Polypedilum nubeculo-
sum (Meigen)
Polypedilum simulans
Townes
Polypedilum sp.
Tany tarsus devinctus
(Say)
Tany tarsus jucundus
(Walker)
Tany tarsus nigricans
(Johannsen)
Tany tarsus varius
Townes
Tany tarsus sp.
Xenochironomus scupula
Townes
Cryptochironomus bla-
rina Townes
Cryptochironomus digi-
tatus (Malloch)


26.2


26.2


26.2



26.2










26.2

26.2


26.2





Cryptochironomus fulvus 26.2
(Johannsen)
Tendipes anthracinus
(Zetterstedt)
Tendipes atrovirides
Townes
Tendipes attenuatus
(Walker)

Tendipes dux
(Johannsen)
Tendipes fumidus
(Johannsen)
Tendipes miller i
Townes
Tendipes modestus (Say)
Tendipes neo modestus
(Malloch)
Tendipes nervosus
(Staeger)
Tendipes ochreatus
Townes





26.2


26.2






26.2





Ca++,
ppm,
max






22.0






















22.0




























Mg++,
ppm,
max






4.0






















4.0




























Fe+++,-
PPm,
max






0.0






















0.0




























ci-,
ppm,
max




b

8.5





b



b












8.5








b

b

b











b



so4;
Ppm",
max






1.0






















1.0




























N03-,
ppm,
total
max




43.0


43.0


43.0



43.0










43.0

43.0


43.0





43.0





43.0


43.0






43.0





co3=,
ppm,
max




310


310


310



310










310

310


310





310





310


310






310





BOD,
max




82.0


82.0


82.0



82.0










82.Q

82.0


82.0





82.0





82.0


82.0






82.0





Authors

Jones (1948)


Paine (1956),Roback
(1957)
Jones (1949)
Lindeberg (1958), Paine
(1956), Roback (1957)
Brues (1928)
Paine (1956),Roback
(1957)
Roback (1957)

Paine (1956), Roback
(1957), Wurtz (1960)
Palmen (1956)

Guyer (1956)

Teter (1960)
Paine (1956), Roback
(1957)
Roback (1957)

Paine (1956), Roback
(1957)
Paine (1956)

Jones (1949)
Paine (1956)

Curry (1958)

Curry (1958), Guyer
(1956), Lindeberg (1958),
Tebo (1955)
Curry (1958), Paine
(1956), Roback (1957)
Lindeberg (1958)

Teter (1960), Roback
(1957)
Dicke (1957), Paine (1956),
Lindeberg (1958), Pal-
men (1956)
Paine (1956)

Roback (1957)

Roback (1957)

Roback (1957)
Paine (1956), Roback
(1957)
Guyer (1956),Palmen
(1956)



-------
136
ENVIRONMENTAL REQUIREMENTS OF AQUATIC INSECTS
Table 3. RANGES OF ENVIRONMENTAL FACTORS FOR FRESH-WATER TENDIPEDID SPECIES (CONTINUED)
Species
Tendipedinae (continued)
Tendipes paganus
(Meigen)
Tendipes plumosus
(Linne)
Tendipes riparius
(Meigen)

Tendipes staegeri
(Lundbeck)
P04=,
ppm,
total
max






26.2



Tendipes tendipediformis
(Goetghebuer)
Tendipes tentans
(Fabricius)
Tendipes taxis (Curran)
Tendipes sp.
Glyptotendipes barbipes
(Staeger)
Glyptotendipes lobiferus
Glyptotendipes paripes
(Edwards)
Glyptotendipes sp.

Harnischia tenuicaudata
(Malloch)







26.2


26.2



Ca++,
ppm,
max















22.0









Mg++,
ppm,
max















4.0









Fe+++,
ppm,
max















0.0









cr,
ppm,
max












b


8.5
b


b





so4-,
ppm,
max















1.0









N03-,
ppm,
total
max






43.0











43.0


43.0



CO3~,
ppm,
max






310











310


310



BOD,
max






82.0











82.0


82.0



Authors



Dicke (1957)


Paine (1956), Roback
(1957),Wurtz (1960)
Roback (1957)



Brues (1928), Lindeberg
(1958)

Jones (1959)
Lindeberg (1958)

Paine (1956)
Guyer (1956)

Dicke (1957), Paine
(1956), Wurtz (1960)


 a tr = trace.
 b Six percent sea water.

Field  data  indicate  that some of these larvae have
made  suitable  adaptations  and  have now become
established in these environments.
   Wurtz  and Bridges (1961)  have reported bioassay
studies conducted on several invertebrate forms, in-
cluding T. attenautus,  using solutions  of  zinc and
copper sulfate.   At  present,  the  results are incon-
clusive.

   Biological Oxygen Demand.  Unfortunately, there
are  very few recorded data that can be  used for
comparative purposes.  In many instances, data could
not be used  because of incomplete  classification of
the tendipedids  (Table  3).   Paine and Gaufin  (1956)
have reported that many of the genera of the family
are able to survive in a BOD of 82.0 ppm. Here, as in
the case  of  ionic concentration,  bioassays must be
run on selected species as described by Henderson
(1957).

   Bottom type  and  siltation.  No report was found
discussing the various organic or inorganic settleable
solids  per se. Habitat requirements were listed only
in  general terms of environmental conditions  (Table
4).   The  Aquatic Life  Advisory Committee  (1956)
established  a rating in which organic or inorganic
settleable  solids  affected  production in  different
ways.  The  presence of organisms  will depend upon
the amount  of settleable solids in the water.  Based
upon  a population rating, the various substrata are
                                rated as follows:  Sand,  1; marl,  6; fine gravel, 9;
                                sand and silt,  10.5; gravel and sand, 12; gravel and
                                rubble,  53;  aquatic moss on fine gravel, 89;  and
                                Elodea, 452.

                                   There are  many studies in which a  decrease in
                                population is illustrated by siltation, sludge, hair and
                                fiber deposits, and scums.  No attempt was made,
                                however, to  evaluate   numerically the  amount of
                                settleable solids with the bottom fauna, other than the
                                above  rating.  Studies  on  T. plumosus and T. atten-
                                uatus populations in two Michigan  lakes indicate that
                                a  compact,  homogeneous silt is more productive than
                                either  clay, marl, or  sand.   In  the  case of clay,
                                8 to 12 inches of turbid water was superimposed over
                                the hydrosol.

                                                   CONCLUSION

                                   This  survey  of the tendiped fauna of fresh-water
                                lakes and streams indicates that several species are
                                adaptable to a wide range of habitat requirements.
                                The  species Tendipes  attenuatus, T. riparius, T.
                                staegeri, and  a species  of Glyptotendipes are fre-
                                quently  found  in polluted  areas.   Of these forms,
                                T. attenuatus seems to be the most adaptable.  Pos-
                                sible  reasons  that  this  form  is  able  to endure
                                these conditions may be:  (1) It is adjusted to a wide
                                range  of temperatures;  (2)  it  is  adapted to a wide
                                range  of  hydrogen  ion  concentration;    (3)   it is

-------
                            A Survey of Environmental Requirements for the Midge
                                              137
adaptable to anaerobic conditions;  (4)  it can tolerate
high tensions of CO2;  (5)  it has the ability to adapt
to high ion concentrations as illustrated by salt water
habitats; and (6) it is able to adapt to a variety of hydro-
sols.

   The  presence  of compounds  such  as sulfides,
mercaptans,  and resin  acid soaps has been shown to
be detrimental to bottom fauna (Wilson,  1953). Re-
search involving bioassays with respect to factors in
the environment  will give  additional information re-
garding "levels of tolerance."  Continued field obser-
vations  will  supplement the results observed  in the
laboratory by conditions found in nature.
        Table 4. RANGES OF ENVIRONMENTAL FACTORS FOR FRESH-WATER TENDIPEDID SPECIES
Species
Pelopiinae
Pentaneura carnea (Fabricius)

Pentaneura illinoensis (Malloch)
Pentaneura melanops
(Weidemann)
Pentaneura monilis (Linne)
Pentaneura vitellina (Kieffer)
Pentaneura sp.

Anatopynia dyari (Coquillett)

Anatopynia sp.
Pelopia punctipennis (Meigen)

Pelopia stellata (Coquillett)

Pelopia vilipennis (Kieffer)
Pelopia sp.
Procladius bellus Loew
Procladius choreus Meigen
Procladius culciformis (Linne)
Procladius sp.


Clinotanypus caliginosus
(Johannsen)
Coelatanypus concinnus
(Coquillett)
Diamesinae
Prodiamesa olivacea (Meigen)

Syndiamesa sp.
Diamesa nivoriunda Fitch

Hydrobaeninae
Corynoneura scutallata
(Winnertz)
Corynoneura sp.

Cricotopus absurdus (Johannsen
Bottom type

gravel, sand,
limestone
limestone
gravel, sand,
limestone
marl, plants
gravel
silt, sand, marl,
detritus, plants
shale, gravel,
sand
Chara, silt
shale, gravel,
sand
shale, gravel,
sand
marl, plants

pulpy peat, silt
pulpy peat, silt
gravel, shale
gravel, marl


gravel, sand

gravel, sand,
limestone

detritus, silt,
sand

gravel, sand,
limestone
gravel, sand
gravel, sand

limestone
Depth
in
meters

0.3 to 0.6

0.3 to 1.8
0.3 to 1.8

5.0
0.3 to 0.6
5.0

0.3 to 1.8


0.3 to 0.6

1.8

8.2

22.0
22.0
0.3 to 0.8
25.0


0.3 to 0.6

0.3 to 1.8


0.6


0.3 to 0.6

0.3 to 0.6
0.3 to 0.6

0.3 to 0.6
L
0
t
i
c








X








X

X
X
X







X








L
e
n
i
t
i
c

X

X
X

X
X
X

X


X

X





X
X


X

X


X


X

X
X

X
Water a
P RC

F

C C C
A A A


F


A A A


F F

A A A





F F
A A A


F

A A


F


F

F
F

F
Authors

Paine (1956), Roback (1957)

Paine (1956)
Paine (1956)

Brues (1922),Roback (1957)
Paine (1956)
Jones (1948), Wurtz (1960)

Paine (1956), Roback (1957)

Jones (1949)
Paine (1956)

Guyer (1956), Paine (1956)


Brues (1928)
Guyer (1956)

Paine (1956), Roback (1957)
Dicke (1957), Jones (1949),
Lindeberg (1958), Paine
(1956). Teter (1960)
Paine (1956)

Paine (1956)


Jones (1948)


Paine (1956)

Paine (1956)
Jones (1948), Paine (1956),
Lindeberg (1958)
Paine (1956)

-------
138
ENVIRONMENTAL REQUIREMENTS OF AQUATIC INSECTS
Table 4. RANGES OF ENVIRONMENTAL FACTORS FOR FRESH-WATER TENDIPEDID SPECIES (CONTINUED)
Species
Hydrobaeninae (continued)
Cricotopus bicinctus (Meigen)

Cricotopus exilis (Johannsen)
Cricotopus politus (Coquillett)

Cricotopus tricinctus (Meigen)

Cricotopus trifasciatus (Panzer)

Cricotopus sp.

Hydrobaenus sp.

Tendipedinae
Calopsectra dives (Johannsen)
Calopsectra johannseni (Bause)
Bottom type

gravel, sand

limestone
gravel, sand,
limestone
gravel, sand,
limestone
gravel, sand



gravel, marl,
plants, sand

pulpy peat, silt
shale
Calopsectra neoflavella (Malloch) gravel, sand,

Calopsectra nigripilus
(Johannsen)
Calopsectra sp.


Pseudochironomus richardsoni
(Malloch)
Pseudochironomus sp.

Lauterborniella gracilenta
Lauterborniella varipennis
(Coquillett)
Microtendipes pedellus (DeGeer)


Microtendipes sp.

Paratendipes albimanus (Meigen)

Paratendipes sp.
Polypedilum fallax (Johannsen)
shale, till
gravel, sand,
shale
marl, plants,
sand, shale,
gravel
sand, till

plants, marl, silt,
pulpy peat

marl, plants
limestone
detritus, silt,
marl, plants,
sand
marl, sand, silt,
detritus, plants
marl, plants, till


gravel, till
Polypedilum halterale (Coquillett) plants, marl
Polypedilum illinoense (Malloch)


Polypedilum nubeculosum
(Meigen)
Polypedilum simulans Townes
Polypedilum sp.

Tany tarsus devinctus (Say)
Tany tarsus jucundus (Walker)
Tanytarsus nigricans (Johannsen

clay,sand,shale,
pulpy peat,
gravel
marl, plants

marl, plants
marl,silt,plants,
fibrous peat
marl, plants
marl, plants
marl,plants,till,
Depth
in
meters

0.3 to 0.6

0.3 to 1.8
0.3 to 1.8

0.3 to 1.8

0.3 to 0.6



25.0


10.0
0.3 to 0.8
0.3 to 1.8

0.3 to 1.8

25.0


0.3 to 0.8

4.0




10.0


10.0

10.0


0.3 to 0.8
4.0
0.3 to 0.8


5.0

10.0
25.0

10.0
22.0
10.0
gravel,limestone
L
o
t
i
c












X


X





X




X







X





X



X

X
X

X
X
X

L
e
n
i
t
i
c

X

X
X

X

X



X



X
X

X

X


X



X
X

X


X

X


X
X
X







X
X
X

Water a
P RC

C

A
A

A

C



F


F
C
C C

c

c


F

F

F


C


F

C


C C
F
C


F

F
F

F
F
C

Authors

Baker (1918), Roback (1957),
Paine (1956), Wurtz (1960)
Paine (1956)
Paine (1956)

Paine (1956)

Paine (1956), Roback (1957),
Wurtz (1960)
Brues (1928), Jones (1948)
(1949)
Brues (1928), Paine (1956),
Jones (1948) (1949)

Teter (1960)
Paine (1956)
Paine (1956)

Paine (1956)

Dicke (1957), Paine (1956),
Teter (I960)

Paine (1956)



Jones (1948)


Paine (1956), Roback (1957)


Jones (1949)

Lindeberg (1958), Paine (1956
(1956), Roback (1957)
Brues (1928)
Paine (1956), Roback (1957)
Roback (1957)
Paine (1956), Roback (1957),
Wurtz (1960)

Palmen (1956)

Guyer (1956)
Teter (1960)

Paine (1956), Roback (1957)
Roback (1957)
Paine (1956), Roback (1957)


-------
                         A Survey of Environmental Requirements for the Midge
                                                           139
Table 4. RANGES OF ENVIRONMENTAL FACTORS FOR FRESH-WATER TENDIPEDID SPECIES (CONTINUED)
Species
Tendipedinae (continued)
Tony tarsus varius Townes

Tany tarsus sp.
Xenochironomus scapula Townes
Cryptochironomus blarina
Townes

Cryptochironomus digitatus
(Malloch)

Cryptochironomus fulvus
(Johannsen)
Tendipes anthracinus
(Zetterstedt)
Tendipes atroviridis Townes

Tendipes attenuatus (Walker)


Tendipes dux (Johannsen)

Tendipes fumidus (Johannsen)
Tendipes milleri Townes
Tendipes modestus (Say)
Tendipes neomodestus (Malloch)

Tendipes nervosus (Staeger)
Tendipes ochreatus Townes
Tendipes paganus (Meigen)

Tendipes plumosus (Linne)

Tendipes riparius (Meigen)

Tendipes staegeri (Lundbeck)

Tendipes tendipediformis
(Gfoetghebuer)
Tendipes tentans (Fabricius)
Tendipes tuxis (Curran)

Tendipes sp.

Glyptotendipes barbipes (Staeger)
Glyptotendipes lobiferus (Say)
Glyptotendipes paripes (Edwards)

Glyptotendipes sp.

Harnischia tenuicaudata (Malloch]

Bottom type

sand, till,
gravel

limestone, till
marl, clay, silt,
pulpy peat,
shells
rocks, sand, silt,
pulpy peat,
gravel
marl, plants,
sand, silt,clay
silt, algae

silt, sand, marl,
detritus plants
silt, sand, marl,
gravel, detritus,
plants
gravel, sand,
marl, plants
marl, plants
marl, plants
marl, plants
Depth
in
meters

00.3 to 0.6


0.3 to 0.6
10.0


6.0


10.0

9.0

4.0

22.0


8.0

5.0
5.0
5.0
marl, plants, sand, 5.0
gravel, limestone
marl, plants
marl, plants
sand, silt, marl,
detritus, plants
plants, silt, marl,
pulpy peat, clay
gravel, limestone
8.2
4.0
10.0

22.0

8.2
marl, plants, silt
plants, marl, silt,
pulpy peat
marl, plants

silt, plants, marl
8.2

8.2

8.2
sand, marl, plants, 5.0
silt, pulpy peat
silt, marl, plants,
pulpy peat

marl, plants
marl, plants,
sand, peat
pulpy peat, till,
silt, sand
marl, plants,
pulpy peat, silt




5.0
5.0

10.0

10.0

L
0
t
i
c





X


X




X

X

X


X

X




X
X
X

X

X

X

X

X











L
e
n
i
t
i
c

X


X






X





X


X




X





X

X

X









X
X

X



Water a
P RC




C
F


F


F

F

F

A A A


F

F


F

C
F
F

A

C C C

C C

F

F





F
F

AAF



Authors

Paine (1956)

Jones (1949)
Paine (1956)
Curry (1958)


Curry (1958), Guyer (1956),
Lindeberg (1958), Tebo(1955)

Curry (1958), Paine (1956),
Roback (1957)
Lindeberg (1958)

Teter (1960), Roback (1957)

Dicke (1957), Paine (1956),
Lindeberg (1958), Palm en
(1956)
Paine (1956)

Roback (1957)
Roback (1957)
Roback (1957)
Paine (1956), Roback (1957)

Guyer (1956), Palmen (1956)



Dicke (1957)

Paine (1956), Roback (1957),
Wurtz (1960)
Roback (1957)



Brues (1928), Lindeberg (1958


Jones (1949)

Lindeberg (1958)
Paine (1956)
Guyer (1956), Warnhoff (1957)

Dicke (1957), Paine (1956),
Wurtz (1960)


 a Water P R C  = P = pollutional
                 F = few
R = recovery from pollution    C = clean
C = common                 A = abundant

-------
140
ENVIRONMENTAL REQUIREMENTS OF AQUATIC INSECTS
                                             REFERENCES
Aquatic  Life  Advisory Committee.  1956.  Aquatic
Life Water  Quality. Criteria.  Sewage and Industrial
Wastes.  28(5): 678-690.
Baker, F. C.  1918.  The Productivity of Invertebrate
Fish Food on the Bottom of Oneida Lake, with Special
Reference to Mollusks.  Technical Publication 9, New
York  State  College of Forestry.   XVIII(2): 1-265.
Bay, E. C.  1960.  The Feasibility and Advisability of
Chironomid Control with Special Reference to Chautau-
qua Lake,  N.  Y.  University Microfilms, Inc., Ann
Arbor. 184 pages.

Bay,  E.  C.  and L. D.  Anderson.  1960. Progress
Report  III.    Chironomid Midge Project of the Los
Angeles  County Control District Water Spreading
Grounds near Whittier,  California.  Mimeographed.
28 pages.

Brues, C. T. 1928. Studies on the Fauna of Hot Springs
in  the  Western United States and  the Biology of
Thermophilous  Animals.  American Academy of Arts
and Sci.  Proceedings 63(1927-28): 139-229.

Brundin, L.   1949.  Chironomiden und andere boden-
tiere der sudschwedischen urgebirgsseen. Institute of
Freshwater Research.  Drottmingholm.  Report No.
30: 1-914.

Curry,  L. L.  1958.  Larvae and Pupae of the Species
Cryptochironomus (Diptera) in Michigan. Limnology
and Oceanography 3(4):  427-442.

Dicke,  R.  J.    1957.   Winnebago Lake  Fly Control
Project.  Annual Report. Mimeographed. 20 pages.

Edwards, F.  W.  1929.  British Non-biting Midges
(Diptera: Chironomidae)  London Entomological Soc-
iety Transactions 77: 279-439.

Freeman, P.    1955.  A Study  of the Chironomidae
of Africa  South of the Sahara.  I.  Bulletin British
Museum Natural History Ent. 4: 1-67.

Freeman, P.   1956. A Study of the  Chironomidae of
Africa  South  of the Sahara.   II.    Bulletin British
Museum Natural History Ent.  4: 285-366.

Freeman, P.    1957.  A Study  of the Chironomidae
of Africa South of the  Sahara,  III.   Bulletin British
Museum Natural History Ent. 5: 321-426.

Freeman, P.   1958.  A study of the Chironomidae of
Africa  South  of the Sahara.   IV,   Bulletin British
Museum Natural History Ent. 6: 261-363

Freeman, P.   1961.  The  Chironomidae (Diptera) of
Australia, Australian Journal of Zoology 9(4):  611-737.

Guyer, G.   1956.  Seasonal Distribution of Midges in
Farm Ponds.  Mimeographed. 4 pages.

Hankinson,  T.  L.   1908.   A  Biological  Survey of
Walnut Lake, Michigan. Annual Report of the Michigan
Geological Survey:  155-288.
                                 Henderson, C.  1957. Application factors to be Applied
                                 to Bioassays for  the Safe Disposal of Toxic Wastes.
                                 Transactions of Seminar on Biological  Problems in
                                 Water Pollution:   31-37.

                                 Johannsen,  O.  A.   1937a.  Aquatic Diptera, Part III.
                                 Chironomidae: Subfamilies Tanypodinae, Diamesinae,
                                 and Orthocladinae.   Memorial  Cornell  University
                                 Agricultural Experiment Station 205:   1-84.
                                 Johannsen,  O.  A.   1937b.  Aquatic Diptera, Part IV.
                                 Chironomidae:  Subfamily Chironominae.   Memorial
                                 Cornell  University Agricultural  Experiment Station
                                 210:  1-52.

                                 Johannsen,  0. A.,  H. K. Townes, F. R. Shaw, and E. G.
                                 Fisher.   1952.  Guide  to the Insects of Connecticut,
                                 Part IV.  The Diptera or True Flies.  Fifth Fascicle:
                                 Midges  and Gnats.  Bulletin No. 80.  State Geolo-
                                 gical and Natural  History Survey.  1-255.

                                 Jones, J. R. E.   1948.   The Fauna of Four Streams
                                 in  the  "Black Mountains* District  of  South Wales.
                                 Journal of Animal Ecology 17(1):  51-65.

                                 Jones, J. R. E. 1949.  A Further Ecological Study of
                                 Calcareous Streams in the "Black Mountains" District
                                 of  South Wales.   Journal  of Animal Ecology  18(2):
                                 142-159.

                                 Kipling,  E. F.  1950.  Some Personal  Observations
                                 on the Treatment of Clear Lake, California for the
                                 control of the Clear Lake gnat.  Mosquito News 10(1):
                                 16-19.

                                 Leathers, A. L.   1922.  Ecological  Study of Aquatic
                                 Midges and Some Related Insects with Special Ref-
                                 erence to Feeding Habits. U. S. Bureau of Fisheries.
                                 Bulletin 38: 1-61.

                                 Lindeberg, B,   1958.    A New  Trap for Collecting
                                 Emerging Insects from  Small Bockpools with Some
                                 Examples of Results Obtained.  Suomen Hyonteistie-
                                 teelinen Aikakauskirja—Annales Entomologici Fennici
                                 24(4): 186-191.

                                 Lindquist,  A.  W.  and  A. R. Roth.   1950.  Effect of
                                 dichloro—diphenyl  dichloroethane on Larvae of the
                                 Clear Lake Gnat  in California.  Journal of Economic
                                 Entomology 44: 572-577.

                                 Malloch, J. R.  1915. The Chironomidae, or Midges of
                                 Illinois,  with  Particular Reference  to the  Species
                                 Occurring  in  the Illinois  River.   Bulletin  of the
                                 Illinois  State  Laboratory  of Natural  History, 10:
                                 273-543.

                                 Paine, G. H. and A. R. Gaufin.  1956.  Aquatic Diptera
                                 as Indicators  of  Pollution  in a  Midwestern Stream.
                                 Ohio Journal of Science.  56(5):  291-304.
                                 Palmen,  E.   1956.  Periodic  Emergence in Some
                                 Chirinomids—an  Adaptation of Nocturnalism.  Bertil
                                 HanstromL  248-256.

                                 Richardson, R. E.  1928.  The  Bottom Fauna of the
                                 Middle Illinois River,  1913-1925.  Bulletin Illinois
                                 Natural History Survey, XVII:  387-475.

-------
                 The Influence of Predation on the Composition of Fresh-Water Communities
                                              141
Roback, S. S.   1957.   The Immature Tendipedids of
the Philadelphia Area.   Monographs  of the Academy
of Natural Science  of  Philadelphia,  No.  9:  1-152.
28 plates.

Tebo, L. B.  1955. Bottom Fauna of a Shallow Eutro-
phic Lake,  Lizard Lake,  Pocahontas County, Iowa.
American Midland Naturalist 54(1): 89-103.

Teter, H.  E.  I960. The Bottom Fauna of Lake Huron,
Transactions of the American Fisheries Society 99(2):
193-197.

Thienemann,  A.  1954.  Chironomus.  Die Binnenge-
wasser.  Band XX Stuttgart.  834 pages.

Townes, H.  K., Jr.   1945.   The Nearctic Species of
Tendipedini.    (biptera,  Tendipedidae   (=  Chirono-
midej]   . American Midland Naturalist  34: 1-266.
Walker, J. R.  1951. An Evaluation of the 1949 Clear
Lake Gnat Project.  Calif.  Mosquito Control Associa-
tion Annual Conference Proceedings and Papers 19:
94-96.
Warnhoff, E. J.,  Jr.  1957. Research on the Biology
and Control of Midges in Central Florida—A Progress
Report and Supplement.  Typed.  34 pages.
Wilson, J. N.   1953.  Effect of Kraft Mill Wastes on
Stream Bottom Fauna.  Sewage and Industrial Wastes
25(10):  1210-1218.
Wurtz,  C.  B.  1960. A Biological Method Used in the
Evaluation  of Effects of  Thermal  Discharge in the
Schuylkill River.  Proceedings 15th Industrial Waste
Conference, Purdue.  Pages 461-472.
Wurtz,  C.  B.  and C. H. Bridges. 1961.  Preliminary
Results  from Macroinvertebrate Bioassays.  Penn-
sylvania Academy of Science XXXV: 51-56.
                       THE INFLUENCE OF PREDATION ON THE COMPOSITION

                                   OF FRESH-WATER COMMUNITIES


                                              T. T. Macan*
   I have data on the effects of predation in a moor-
land  fishpond  and in a  small stony  stream.   The
invertebrate fauna of the  fishpond was studied for
5 years, during which the water was kept free of fish,
except  for  a  few eels.  Five  hundred Salmo trutta
were introduced in the autumn of 1960 and the same
number  a year  later, which, since the pond is but
about half a hectare (1  acre) in  extent, should have
produced a considerable predation pressure. Tadpoles
of Rana and Bufo, which have no reaction that would
keep them concealed from  predators, disappeared at
once;  so did  the surface-feeding Notonecta.   The
numbers of other animals have so far  changed little.
Presumably  the trout catch only those specimens
that  wander out  of  their  normal habitat,  in which
some other factor is controlling the density of popula-
tion.   The most abundant animals are the nymphs of
two  species of  Zygoptera  (Odonata)   and of Lepto-
phlebia  spp.  (Ephemeroptera).  One-year dragonfly
nymphs  were much more abundant than usual.   This
did  not,  as  far  as could be  seen, lead to increased
cannibalism  by  older nymphs nor to  the death of a
high  proportion of the population  from starvation. It
was observed, however, that, at the end of the second
summer, when normally all  nymphs are nearly  full-
grown,  only  a proportion had reached this length and
the  rest had grown  very little.  This suggests that
the size of the population is limited by the number of
territories  in which nymphs can procure enough to-
eat to grow  at the usual rate.  That is not, however,
the line I wish to follow today.
   The  stony stream was affected by the overloading
of a septic tank, and a great increase in the number
of planarians is thought  to have been connected with
the increased amount of food contributedby the organic
matter  washed  out of it.  The total numbers of Poly-
cells felina  taken  in 1950,  1951,  and 1952  were
respectively 2,  2, and 6,  per square metre, whereas
comparable  collections since the overloading  have
yielded up to 1,000 specimens.   Certain species of
Ephemeroptera  and Plecoptera have gradually become
scarcer and some have disappeared. This is  attributed
to predation by the  planarian.  Had it been owing to
pollution, the effect would have been more sudden and
would have been manifest sooner.  I gave a full account
of  these  results at a symposium on  Running Water
held in Lucerne last year  and organized by Societas
Internationalis Limnologiae. It is not necessary tore-
peat the details here.  I wish now to consider certain
wider implications of the  findings.

   Predation on insects by other invertebrates may be
an  important factor in the characteristic differences
between the littoral faunas of productive  and  un-
productive lakes.  Table 1 presents data about those
groups  that  are well represented by species that can
be  identified in two lakes:  Esrom,  a rich lowland
lake in Denmark, and Windermere, which lies in the
poorer  soils of the English Lake District. There are
about  10  times more animals per  square metre in
Esrom  than  in Windermere, but the point to be under-
lined in the present context is that the composition of
   Fresh-Water Biological Association, Ambleside, Westmorland, England.

-------
 142
ENVIRONMENTAL REQUIREMENTS OF AQUATIC INSECTS
     Table 1. COMPARISON OF LITTORAL FAUNA OF ESROM LAKE (BERG 1938) AND WINDERMERE
                                             (MOON 1934)

Mollusca a
Amphipoda
Isopoda
Hirudinea
Oligochaeta
Planarians

Trichoptera
Ephemeroptera
Plecoptera

No. of
spp.
14
2
1
10
14
6

11
1
1

Indiv/m2
at
0.2m
1,410
768
548
454
304
2+

338
20
76
3,920
%
36
19
14
12
3

89
8
1
2
11
No. of
spp.
9
1
2
6
=4+c
5

18+c
6
6

Indiv/m2
on rocky
shore
120 d
37
5
1
17
3

217
12
5
417
%
30
9
1
1
4
1
45
50
3
1
54
              Snails only.
              Excluding bur rowers.
              Identifications uncertain.
              Ninety were Ancylus fluviatilis, which is not recorded in Esrom Lake.
the fauna is markedly different in the two lakes.  Berg
found only one species of Asellus in Esrom, whereas
two have been recorded in Windermere, but every other
group that does not belong to the Insecta is represented
by more species in Esrom than in Windermere.  The
converse  is true of the  insect groups. Windermere
does  not  represent  an extreme type  by any means,
being one of the most productive lakes in the English
Lake  District.   These  can be arranged in a series
(Pearsall,  1921)  .  At the other  extreme  lie oligo-
trophic lakes such as Ennerdale and Wastwater. None
has been surveyed, but it is known that only two species
of gastropod (Macan, 1950) and no planar ians (Reynold-
son, personal  communication) occur in Ennerdale.
Asellus has not been recorded from it, and the number
of species of Hirudinea  will certainly be smaller, to
judge from what  is known of their ecology elsewhere
(Mann, 1955).  The proportion of insects in its fauna
is probably  distinctly bigger than in Windermere.

   Many  of the groups that are so well represented
in the rich lake came to fresh water from the sea.  It is
possible that some have not been able to colonize poor
lakes because they cannot take up from the waters of
such places all the ions they require.  Calcium is one
element that is frequently limiting, and the number of
species of snail  (Boycott,  1936), leech (Mann, 1955),
and flatworm (Reynoldson, 1958) has been  shown  to
decrease  in a series of waters in which the concen-
tration  of calcium is falling. It is also likely that
decreasing  food  supply  plays a part, or the  more
unproductive lakes may lack some growth factor of the
type postulated by Lund (Mackereth, Lund, and Macan,
1957).

   Insects  have invaded fresh water after having suc-
cessfully  colonized  the  land, where  their survival
depended  on an impermeable cuticle that prevented
drying up, and on their ability to obtain everything they
required from their food.  These properties enabled
                                them to invade waters with a very low concentration
                                of  dissolved substances.   Their relative scarcity in
                                richer places cannot be owing to anything unfavourable
                                about  the water  or the  substances dissolved in  it,
                                though  there is a possibility that oxygen could be im-
                                portant.  Unfortunately, insufficient samples have been
                                taken at the time when a critical low value is likely to
                                be  reached, that is,  just before dawn.   I postulate
                                that their scarcity  is related to the abundance of the
                                other animals, which eat them just as the planarians
                                in  the stream ate them.  Biotic influences, then, play
                                an  important part in determining the structure of the
                                communities inhabiting different kinds of lakes.
                                   If an animal  is to  survive among many  other
                                animals, some method of protecting its eggs is probably
                                of the highest importance. This is lacking in Ephemer-
                                optera  and Plecoptera.   Among the former, a few
                                species of  Baetis crawl  into the water and glue their
                                eggs to a stone, but most wash a clump of eggs off the
                                abdomen by dipping the  tip of it into the water.  The
                                eggs then fly apart and fall to the bottom.  The eggs of
                                Plecoptera are dispersed  in the same  way, when a
                                female swims across the water surface. Many must
                                come to  rest  in the algal felt covering the surface of
                                stones, where they will  be eaten incidentally by any
                                algal browser  such  as a snail. Others, falling between
                                the stones,  may land in accumulations of debris and in
                                due course  may be devoured by some detritus feeder.
                                Most species  lay many  eggs and so the nymphs are
                                small.   Frequently they  emerge in autumn and grow
                                slowly, and spend, therefore a long time in the small,
                                vulnerable stage.

                                   In contrast, the animals typical  of rich waters
                                produce their  eggs  in such a way that there is much
                                less danger that the eggs  will be eaten. The snails lay
                                a number together  in a gelatinous envelope too large
                                to  be eaten incidentally by a browser or by most
                                carnivores.  Leeches and flatworms lay their eggs in
                                cocoons.   Gammarus  and Asellus  keep theirs  in a

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                  The Influence of Predation on the Composition of Fresh-Water Communities
                                               143
brood pouch  until the  young hatch, and they are safe
from everything except animals large enough to devour
the brooding parent. All these groups lay fewer eggs
than the insects  mentioned and generally bring them
forth at a time of year  when conditions for growth are
optimum.  The young are, therefore, larger on emer-
gence and grow quickly, so that they are in danger from
 all but the largest carnivores for ashortperiod only.

    At present there is a good deal of speculation about
 this hypothesis.   If  it proves to be well founded, it
 will add  a complicating  factor  to any  "Saprobien-
 system,"  for these systems seem to make insufficient
 allowance for the effects of species on  each other.
                                             REFERENCES
Boycott,  A.  E.   1936.   The habitats  of fresh-water
Mollusca  in  Britain.   J.  Anim.  Ecol.  5, 116-186.

Macan, T. T.  1950.  Ecology of fresh-water Mollusca
in the English  Lake District J.  Anim.  Ecol. 19,
124-146.

Mackereth, F. J. H., Lund, J. W. G.,and Macan, T. T.
1957.  Chemical analysis in ecology illustrated from
Lake District tarns  and lakes.   Proc.  Linn. Soc.
Land. 167, 159-175.
Mann, K. H. 1955.  The ecology of the British fresh-
water leeches. J. Anim. Ecol. 24, 98-119.

Pearsall, W. H.  1921.  The development of vegetation
in the  English lakes  considered  in relation to the
general  evolution  of  glacial lakes and  rock basins
Proc. Roy. Soc. B.  92, 259-284.

Reynoldson,  T. B.   1958.  Triclads and lake typology
in northern Britain - qualitative aspects. Verh. int.
Ver. Limnol. 13,  320-330.
                                              DISCUSSION
                     (GAUFIN)
                    (LEONARD)
   Comments following Dr. Gauf in's paper included one
to the effect that it is probably the eggs and not young
stoneflies that survive over periods  of drought.  Also
in certain species, it is during the egg stage  (a fairly
extensive period) that low oxygen concentrations pos-
sibly have the most detrimental effect, because nymphs
can shift their own location for a more adequate supply
of oxygen.

   Older nymphs of 68 species have  been observed to
begin and increase their "pumping"  or  "pushup"  rate
as the dissolved-oxygen level was reduced.  When the
level reached a certain low point, the pumping ceased
and the animals became relatively inactive, as though
conserving energy.

   Concerning toxicity of pesticides, such compounds
as DDT, aldrin, endrin, heptachlor,  dieldrin, fishtox,
and others have been used in static and continuous-
flowthrough experiments on stonefly nymphs, and the
general indication is that they are more sensitive than
most fishes.
   Relative  toxicity  of  several pollutants  to  fish,
caddisfly larvae, stonefly nymphs, and stonefly eggs
was discussed at some length.  In a pollution case in
Africa the toxic substance killed many stonefly nymphs,
but not their eggs or fish that were in the  same stream.
In another such instance in Britain an unknown quantity
of BHC  killed many  stonefly and caddisfly species
with no apparent kill of fishes.
   Lab studies indicate that a species of Gammarus
is just as sensitive to some insecticides as the stone-
flies,  and that certain caddisflies (Hydropsyche and
Arctopsyche) are less sensitive.

   A  final  item of  interest  involved stonefly  life
cycles.  Pteronarcys  californica has a 3-year cycle;
Acroneuria pacifica,  A.  media,   and Pteronarcella
badia a 2-year cycle; andAlloperla, Isoperla, Nem-
oura, and Taeniopteryx, etc., all have a 1-year cycle.
   An informative exchange of observations on several
 species  of  mayflies followed Dr. Leonard's paper.
 In British streams, Heptagenia seems limited to water
 temperatures of 18° C  or less.  In Irish limestone
 lakes,  one species of this  genus occurs abundantly,
 but  another species dominates the limed-fissured
 areas  around  the  edge of Ireland.   In Michigan,
Stenonema  is common  in  streams flowing  through
 glacial   drift,  but  in waters that flow  over Pre-
 Cambrian bedrock,  Heptagenia  is the common may-
 fly.

   Studies  in Switzerland indicated that one  mayfly,
Rhithrogena, the  gills   of  which serve as a  sucker
 attachment  to  the substrata,  shows an  increase  in
 oxygen  consumption with increasing water  current.
 The lethal concentration decreases as water current
 increases. Heptagenia, the gills of which can be used
 to  cause a  current of  water to flow over the body,
 shows  little  or no change in oxygen consumption with
 increased  water flow.   As a possible consequence,
 the  first species seems  limited  to running water,
 whereas the latter is found in lakes and streams.  In
 another  study,  oxygen  consumption apparently in-
 creased  as dissolved-oxygen concentration increased;
 the investigators thought this might be due to some
 experimental artifact.

   Another interpretation of the  Switzerland work was
 that the  metabolic rates were depressed at low-flow
 low-oxygen levels and that when the flow increased,
 the  metabolic  rates merely  returned   to  normal
 (higher)  levels.

   A question for future  consideration was then put to
 the audience: Is the maximal activity dependent on the
 water flow (bringing more oxygen) or merely indicative
 of the conditions persisting at that time?

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144
ENVIRONMENTAL REQUIREMENTS OF AQUATIC INSECTS
                     (ROBACK)

   Discussion of Dr. Roback's paper included several
comments  concerning the  high carbon dioxide levels
and the  significance  of BOD  readings alone.  One
investigator reported on a stream polluted by heavy
metal  wastes.   The  caddisflies  "stayed put" when
mayflies disappeared and fish populations were some-
what reduced.

                      (CURRY)

   During  the discussion  of Dr.  Curry's  paper, he
described a tank that is being used to study the  effects
of anaerobic  conditions on midge larvae. It is stain-
less steel, portholes  and  cover are of plexiglas, and
it  is built  to  withstand 15 atmospheres of pressure.
Methane, carbon dioxide,  hydrogen sulfide, or other
gases  can  be bubbled into the closed tank containing
substratum and animals in their original water. The
portholes  allow  observation.   Careful handling (as
with other  test animals) appears extremely important.

                      (MACAN)

   In the discussion of Dr. Macan's paper the possible
reasons  for the upsurge of planarians were explored.
It was suggested that perhaps many small planarians
                                that usually die off were sustained by the addition of
                                sewage  fauna and flora.  These then gave rise to a
                                large  population of adult planarians  that possibly
                                were  able  to prey upon some  of the insect larvae.


                                   A  comment  was made  to  the  effect  that  most
                                generally in  terrestrial  situations, predator popula-
                                tions  rise  and  fall as  a result of prey population
                                changes, rather than cause such changes.  In aquatic
                                situations,  often the abundance of predators seems to
                                have  a  great effect  on  the prey  numbers.  In one
                                illustration comparing three similar southern ponds,
                                one with bass only had a  large number of bottom
                                organisms, another with bass  and  bluegills  had only
                                a  sparse  bottom  fauna,  and a third,  greatly over-
                                populated with bluegills, had virtually no typical midges
                                or other aquatic insects.


                                   In  many pollution situations, a common occurrence
                                seems to be  that  when predators are killed off, prey
                                populations develop in vast numbers.

                                   In  some northern thermally  stratified lakes man-
                                aged  by trout stocking,  one  possible  reason for the
                                decrease in the general  condition of these fish after
                                3 to 6 years is that they clean out the readily available
                                bottom  fauna and  simply do  not  get enough food.

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               ENVIRONMENTAL REQUIREMENTS OF FISHES AND WILDLIFE

                                 F. T.K.  Pentelow, Chairman (Fishes) *
                                 R.E. Johnson,  Chairman (Fishes and Wildlife) t

                               DISSOLVED OXYGEN REQUIREMENTS OF FISHES t

                                  Peter Doudoroff § and Charles E. Warren //
                   INTRODUCTION

    Minimum dissolved oxygen concentrations that can
 be tolerated by different fishes for limited periods
 of time  have been determined in various ways by
 a number  of investigators.   The results of most of
 these studies  have been briefly but adequately sum-
 marized elsewhere (Doudoroff, 1957; Tarzwell, 1957;
 Townsend and Earnest, 1940; Ellis, 1937).  Doudoroff
 (1957) concluded that, in the absence of other harmful
 conditions  or agents,  "mortality  of  fishes at con-
 centrations (of dissolved  oxygen) near and  above
 3 ppm  is  not to  be  expected ordinarily,  even when
 the  concentrations persist for  long periods.  Con-
 centrations in the neighborhood of  2  ppm often may
 be critical for sensitive forms.  Yet, at moderately
 low  temperatures and under  otherwise favorable
 conditions,  concentrations  near and  below  1 ppm
 evidently can  be  tolerated for long periods  not only
 by .the  most  resistant species, but  also by  more
 susceptible fishes which  have  been  thoroughly  ac-
 climatized  to  low dissolved oxygen concentrations."
 Tolerance  is  not, of  course,  considered here  as
 equivalent  to  the ability  to  survive and  thrive in-
 definitely in a natural environment under the specified
 conditions.

   Apparently,  for reasons discussed  by Tarzwell
 (1957) and  others, it is now  generally  realized that
 fishes cannot  be  expected to thrive in  their natural
 habitat  at  barely  nonlethal  oxygen concenti ations.
 Dissolved oxygen  concentrations below 3 milligrams
 per liter (or ppm) in waters inhabited by salmonids
 or other sensitive and valuable fish  species,  and
 concentrations below 2 milligrams per liter in waters
 inhabited only by  relatively tolerant species  of value
 probably are not deemed satisfactory or acceptable
 by anyone  charged with  water pollution prevention
 and control.   Higher concentration levels  now seem
 to be generally prescribed by regulatory agencies
 that  have  adopted specific  standards  applicable to
 waters in which thriving fish populations  are to  be
 fully protected.

    Fishes  have been  found to  grow  little or  not at
 all,  and even  to  lose weight  in the presence of an
abundant  supply  of food,  at reduced oxygen con-
centrations that  could be tolerated indefinitely or for
long periods of time (Davison et al., 1959; Herrmann,
Warren, and Doudoroff, 1962; Stewart, 1962). Swimming
performance  also  has  been  found  to  be impaired
at such concentrations (Fry, 1957; Katz, Pritchard,
and  Warren, 1959; Davis  et al.,  1963).   Salmonid
larvae  newly hatched  after embryonic development
at constant  low  oxygen  concentrations  that did not
demonstrably influence the survival of the embryos
or hatching  success have been found to be exceedingly
small and weak (Silver, I960; Shumway, 1960).

   The  sublethal adverse effects of reduced oxygen
concentrations have not until recently been studied
intensively,  however,  and they clearly deserve more
attention than they have  received in  the past. Some
of these effects can be precisely measured and related
to their true causes only through laboratory experi-
mentation.  The difficulty of estimating the ecological
significance  of  effects  observed  under  laboratory
conditions  should not be regarded (as it seems to have
been by Moss and Scott,  1961) as a valid justification
for continued emphasis on the determination of oxygen
concentrations that are barely tolerable for resting
and  fasting fish, and  at  which normal development,
growth, and  activity are impossible.  The obstacles
to reliable interpretation  of  the experimental data
with reference to natural or field conditions, which
is essential to sound practical application of the data,
must be overcome through intensified effort.
   In this  paper,  the  available  information on the
nonlethal  effects on fresh-water. fishes of reduced
oxygen  concentrations,  of  abnormally high concen-
trations and of large  diurnal fluctuation of concen-
tration is  reviewed briefly, with emphasis on the most
recent  advances of knowledge based on laboratory
experiments.  In  the  concluding discussion,  some
possible new ways of arriving on ecologically sound
conclusions concerning the dissolved oxygen require-
ments  and other  water quality requirements of fishes
through laboratory experimentation  are suggested,
after consideration  of some of  the  interrelations
and the  probable  ecological significance of the various
kinds of  data summarized.   It  is  realized that an
attempt to  interpret or synthesize fully  the  avail-
 * Ministry of Agr., Fisheries and Food, Whitehall Place, London SW1, England.
 t Chief, Division of Sport Fisheries, U.S. Fish and Wildlife Service, Washington, D.C.
 { A contribution from the Pacif.c Cooperative Water Pollution and Fisheries Research Laboratories, Oregon State University Corvalhs, Oregon.
   Oregon State University research reported in this Paper was supported in part by Research Grants Nos. RG-4352 and WP-135 from the U.b,
   Public Health Service. Special Report No. 141, Oregon Agricultural Experiment Station.
 § Robert A. Taft Sanitary Engineering Center, U.S., Public Health Service.
   Department of Fish and Game Management, Oregon State University.
// Assoc. Prof., Dept. Fish and Game Mgmt., Oregon State U-, Corvallis, Oregon.

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146
ENVIRONMENTAL REQUIREMENTS OF FISHES AND WILDLIFE
able knowledge would be premature, for essential in-
formation of various kinds  still is lacking and much
of it can be expected to become available soon.  It is
hoped, however, that by focusing attention on some of
the major unsolved problems the concluding discussion
will be helpful in stimulating and guiding into profit-
able channels some of the needed additional research.
EFFECTS OF VARIATIONS OF DISSOLVED OXYGEN

EFFECTS ON OXYGEN CONSUMPTION

   Data on the influence of oxygen concentration on
the oxygen  uptake rates of fish have been recently
reviewed and discussed by  Fry (1957) and by Winberg
(1960) and so will not be  considered in detail here.

   The oxygen consumption rate of undisturbed, unfed,
and mostly resting fish cannot be much reduced through
suspension  of any unessential  muscular activity.
Therefore, a reduction of  oxygen concentration  to a
level that is not nearly sufficient for the maintenance
of this  resting or  "standard" uptake rate can be ex-
pected to result in interference with essential meta-
bolic processes.  Death of the fish can be expected
to follow  soon, until life can be indefinitely sustained
at the low oxygen concentrations largely or entirely
by  anaerobic  metabolism, as it has been reported
to be sustained  at low temperatures in  some  fish
(Blazka, 1958).   Moss and Scott  (1961)  found  that
resting  largemouth bass, Micropterus salmoides,
bluegill, Lepomis macrochirus,  and  channel catfish,
Ictalurus punctatus, held  at  25, 30, or 35°C   in a
respirometer in which the oxygen concentration was
gradually reduced, usually showed no marked reduction
of oxygen consumption  rates  until  a  lethal  oxygen
concentration was reached and  the fish were about
to die.

   The  rate  of oxygen consumption of active brook
trout, Salvelinus fontinalis,  has been  found  to be
dependent on oxygen  concentration  at  concentration
levels near  or even  well above the air-saturation
level (Job,  1955; Basu,  1959).  When the rate was
found to be dependent on  oxygen concentration only
at  much lower  levels (e.g., Graham,  1949),  the
fish  may  not have  been  stimulated  to  maximum
activity,  or  they  may have  been  unhealthy (e.g.,
anemic).   Acclimation of brook trout to reduced
oxygen  concentrations  has been shown to influence
the  "active" oxygen  uptake rated  (Shepard,  1955).

   Basu (1959)  and Fry  (1961)  have reported  little
or  no  increase of oxygen uptake  rates of active
brook trout and of carp, Cyprinus carpio, with three-
fold to  sixfold increases of swiming speed.  Recent
introduction  of  the fish into  a  respirometer could
have  evoked a maximal oxygen  uptake rate at each
level of performance.  However, Basu reported also
that  large  increases  of  the oxygen  uptake rates
of active  trout resulted from  mild electrical stimu-
lation apparently without  any increase of  activity
(swimming speed).   The  physiological significance
of published data on active  oxygen uptake rates of fish
and  their dependence on  oxygen concentration thus
                                 is still  somewhat obscure.   Further clarification
                                 thereof is needed before these metabolic rate data
                                 can  be properly  related to  data on performance,
                                 or. used very effectively in evaluating the performance
                                 capabilities of fishes at different oxygen concentra-
                                 tions.   Fry's (1947, 1957) conclusion that the "cruis-
                                 ing speed" of fish increases  as  the  square  root of
                                 the "metabolic  difference" or "scope for activity"
                                 (i.e.,  the  active oxygen uptake rate less the standard
                                 rate)  increases can now be accepted only with some
                                 reservations.
                                 EFFECTS ON SWIMMING PERFORMANCE

                                    Davis et al., (1963)  found that the maximum sus-
                                 tained swimming  speeds of  juvenile  coho  salmon,
                                 Oncorhynchus kisutch,  and chinook salmon 0. tsha-
                                 wytscha, at  temperatures of  10  to  20°C  usually
                                 declined with any considerable reduction of  oxygen
                                 concentration from  air-saturation level.  In other
                                 words, these speeds  usually were dependent on oxygen
                                 concentration at all concentration levels below the
                                 saturation  level.  One  lot of chinook salmon, which
                                 may  have  been anemic, was notably exceptional.
                                 The performance  of these fish at high oxygen con-
                                 centrations was not markedly better than that observed
                                 at  concentrations  between  5  and 7 milligrams per
                                 liter  in  tests  performed at 20 °C.   Graham (1949)
                                 observed a similar relation between oxygen concentra-
                                 tion  and the  cruising  speed  of  brook  trout  in an
                                 experiment with three fish tested in a rotating annular
                                 chamber at 8°C.

                                    Figure  1  shows  the relation, at each of three
                                 different temperatures  (10°, 15°, and 20° C), between
                                 oxygen  concentration and the  lowest water  velocity
                                 that  could not  be  resisted  by all  individuals  in a
                                 group of five  underyearling coho salmon subjected
                                 to gradually increasing velocities (0.08 fps increments
                                 at  10-minute intervals)  in a  tubular  experimental
                                 chamber.  Curves relating oxygen concentrations to
                                 water velocities at   which  swimming failure  of the
                                 second  fish  occurred  in a  group of  five were not
                                 markedly different in  shape from the  curves based
                                 on  first failures  shown in  Figure 1.   It is  note-
                                 worthy that increases of oxygen concentrations beyond
                                 the air-saturation  levels had little or no influence
                                 on the performance of the salmon.

                                    Recent experiments by M.  L. Dahlberg at Oregon
                                 State  University, in which groups of  five  juvenile
                                 largemouth bass were  tested in the tubular chamber
                                 at 25°C, have  shown  the mean maximum sustained
                                 swimming  speeds of these  fish  to be virtually in-
                                 dependent of oxygen concentration at concentrations
                                 above 5 milligrams per liter (Figure 2). The maximum
                                 sustained  swimming speeds  of the first-failing fish
                                 in a  group of five showed a poorer fit to any curve,
                                 but about the same  general  relation  to oxygen con-
                                 centration.

                                    Ferguson's  data  reported by Fry (1957)  indicate
                                 some reduction of the cruising  speed of yellow perch,
                                 Percaflavescens, at reduced  oxygen concentrations
                                 only a little below the air-saturation level, especially

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                                    Dissolved Oxygen Requirements of Fishes
                                                                                                             147
         2   4   6   8   10   12  14  16   18   20  22
           DISSOLVED OXYGEN CONCENTRATION, mg/l


Figure 1. Water velocities at which sustained  swimming failures
        of first-failing wild underyearling coho salmon (in groups
        of 5 fish) occurred at 10, 15, and 20°C,  in relation to
        oxygen  concentration.  (After Davis, Warren, and Dou-
        oroff, 1963.)
                                                            at  the higher test temperatures.   The performance
                                                            of  these  fish,  however,  was  greatly impaired only
                                                            at  concentrations below 3 milligrams per liter.  At
                                                            about this concentration, there was apparently a rather
                                                            abrupt  change  in  the  slope  of curves relating the
                                                            cruising speed to dissolved  oxygen (except  at the
                                                            lowest test temperature of 10°C).


                                                               The  influence  of  oxygen  concentration on the
                                                            resistance of fish to fatigue  resulting from intense
                                                            activity  ("burst" performance) or from prolonged
                                                            swimming  at  speeds  approaching the maximum sus-
                                                            tained or cruising speed has not yet been adequately
                                                            investigated.   Katz,  Pritchard, and Warren (1959)
                                                            have  demonstrated the ability of juvenile coho and
                                                            Chinook salmon, which were tested at 20°  C, to swim
                                                            for  24 or  48  hours  at the moderately high speed of
                                                            0.8  foot per  second at oxygen concentrations  near
                                                            3  milligrams per liter.  These concentrations are
                                                            not  very  much above the concentrations  that would
                                                            be  lethal to the fish under conditions necessitating
                                                            no  sustained  activity.  Maximum  current velocities
                                                            that  can be  resisted for  24  hours or longer at any
                                                            given oxygen  concentration possibly are only slightly
                                                            less than those that can be resisted only for relatively
                                                            short periods (e.g.,  10 or 20  minutes), and "burst"
                                                            swimming  speeds  may not be  influenced by oxygen
                                                            availability as markedly as are the sustained swimming
                                                            speeds.   Some of the  relationships in question are
                                                            now  being investigated to evaluate  and understand
                                                            more fully the effects of reduced oxygen concentrations
                                                            on swimming performance of different kinds, involving
                                                            different intensities of activity.
     1.50
  O

  £  0.50
     0.00
         1        2    3  4  5  6 78910       20   30  40
            DISSOLVED OXYGEN CONCENTRATION, mg/l
                                                            o
                                                            LLI
                                                            <
                                                            O
                                                                                                1956 TESTS
                                                                                               A 1956 TESTS
                                                                                               o SURVIVING FISH
                                                                                               A ONLY OR MOSTLY
                                                                                                 DYING FISH
                                                                                                   I	I
                                                                                                              I
                                                                     234567

                                                                        OXYGEN CONCENTRATION, mg/l
Figure 2. Water  velocities  (mean) at which sustained swimming
        failures of juvenile largemouth bass occurred at 25°C ,
        in relation to ox/gen concentrations.   Each  plotted
        point represents a mean velocity  based on observations
        of 5 fish tested simultaneously at the same oxygen con-
        centration. The  velocity at the time of failure of each
        fish was recorded, and the fish was then  removed from
        the test chamber.
                                                           Figure 3. Percent gains (or losses) in wet weight of underyearling
                                                                   coho salmon fed beach hoppers abundantly  for 19 to 28
                                                                   days at 20°C,  in  relation  to dissolved  oxygen con-
                                                                   centrations.  The curve  has been fitted  to the 1956
                                                                   data only, since the results of 1955 tests probably were
                                                                   affected by a toxicant from rubber tubing.  All of the
                                                                   1956 positive weight gains shown are results of 21-day
                                                                   tests.  (After Herrmann, Warren,  and Doudoroff,  1962.)

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148
ENVIRONMENTAL REQUIREMENTS OF FISHES AND WILDLIFE
EFFECTS ON APPETITE AND GROWTH
   Hermann, Warren, and Doudoroff (1962) found that
the growth rates of abundantly fed underyearling coho
salmon,  which  were  kept  at  20°  C  on  a diet of
beach hoppers (marine amphipods), declined slightly
with reduction of  oxygen concentration from a mean
of about  8.3  milligrams per liter to 6 and 5 milli-
grams per liter,  and  declined  more  sharply with
further  reduction  of oxygen concentration (Figure 3).
The rates  of food consumption declined  likewise;
however,  the gross  efficiency  of food conversion
was markedly reduced only at oxygen concentrations
well below 4 milligrams per  liter.  Therefore,  the
depression  of growth rates  at  moderately reduced
oxygen  concentrations is directly attributable to im-
pairment  of  appetite.  The unimpaired efficiency of
utilization for growth of the relatively small amount
of food consumed  at these concentrations evidently
is ascribable to reduction of activity and of maintenance
food requirements, or to improvement of digestive
and  assimilatory efficiency due  to reduction of  food
intake.   Juvenile  coho salmon consumed very little
food and lost weight at oxygen concentrations averaging
2.0 to 2.3 milligrams per liter  and at temperatures
of 18° to 20°C (Herrmann etal.,  1962; Davison et al.,
1959).  Whether digestive and assimilatory efficiency
is or  is  not materially impaired at the  very low
nonlethal  concentrations has  not  been established.
The resistance  of juvenile coho  salmon to the lethal
and  growth-depressing  effects  of low  oxygen con-
centrations at moderately high, constant temperatures
apparently varies  somewhat with the season or the age
of the fish.
   Stewart (1962) found that the growth rates of juvenile
largemouth bass kept at temperatures near 26°C on
an unrestricted diet of earthworms   generally  were
quite markedly reduced with any  considerable  re-
duction of oxygen concentration from the air-satura-
tion level of  about 8.2 milligrams per  liter (Figure
4).   At high oxygen  concentrations equal to about
two to  three times  the air-saturation value (i.e.,
17.5  to  24  mg/1),  the  percent weight gains of the
bass generally  were  considerably less than  those
observed  at  concentrations near the air-saturation
level in  the  same experiments.  As in the experi-
ments with  coho  salmon (Herrmann  et  al., 1962),
the  food  consumption rates of the bass varied with
oxygen concentration  in much the same way as did
the observed gains in weight, and gross food conversion
efficiencies  generally  were  markedly reduced only
at oxygen concentrations below 4 milligrams per liter.

   The  appetite  and growth rates of the  bass were
greatly impaired by wide diurnal fluctuations of oxygen
concentration so  timed that  the fish were  exposed
once daily to low concentrations at night and through
early  morning.  This impairment was evident  even
when the mean oxygen concentrations (i.e., the properly
weighted  means,  arithmetic  and  geometric, of the
alternating high and  low concentrations to which the
fish  were  exposed) fell  well within the  range of
favorable constant concentrations, and when the dura-
tion of exposure  to lower  concentrations was only
about  one-half  or  even one-third  of each 24-hour
day.   For   example,  in  Experiment  No.  4,  bass
                                  exposed alternately to 2.0 and 17.4 milligrams per
                                  liter for nearly equal periods each day (after gradual
                                  transition from one concentration to the other) showed
                                  a dry  weight  gain in 15.5  days of only 72 percent.
                                  It can  be  seen  from Figure 4 that this weight gain
                                  corresponds approximately to that which would have
                                  occurred at  a  constant  oxygen concentration of 2.6
                                  milligrams per liter. It is far less than the grain (about)
                                  131   to  135 percent)  that would  have occurred at
                                  constant oxygen concentrations equal  to the arith-
                                  metic and geometric  means of the fluctuating oxygen
                                  concentrations (about 10 and 6 mg/1, respectively).
                                  Likewise,  in Experiment 5, bass exposed  to  con-
                                  centrations  near 2.0 milligrams  per liter for less
                                  than one-third  of each  24-hour  day and  to  con-
                                  centrations  near 8.1 milligrams  per  liter for the
                                  remainder  of  the  day (excepting periods of transi-
                                  tion) showed a  dry weight  gain  in 15 days of only
                                  99 percent.  Such  a gain would have occured also at
                                  a constant  oxygen concentration  of only about 3.0
                                  milligrams  per  liter.   At constant  concentrations
                                  equal to the arithmetic and geometric means  of the
                                  fluctuating concentrations (about 6 and 5 mg/1, re-
                                  spectively),  the  dry  weight gains of the fish used
                                  in this experiment would have  amounted  to  about
                                  157   and  142 percent,  respectively  (Figure  4).   It
                                  is evident  that, even in the absence of lethal con-
                                  centrations, mean oxygen concentrations in eutrophic
                                  waters with wide  diurnal fluctuations of dissolved
                                  oxygen content are virtually meaningless and can be
                                  misleading;  growth  rates  of  fish  subjected  to
                                  fluctuating concentrations may be largely dependent on
                                  the  dissolved  oxygen  minima occurring  at  night or
                                  early in the  morning.

                                    200 <-
                                    175  -


                                    150


                                    125


                                    100


                                     75


                                     50


                                     25


                                      0
                                    -25
                                                1
        EXPERIMENT-1-(15 DAYS)
        EXPERIMENT-2-(15 DAYS)
        EXPERIMENT-3-(ll DAYS)
A-	A EXPERIMENT-4-05.5 DAYS)
o	' F.XPERIMENT-5-05DAYS)
••	« cXPERIMENT-6-(15 DAYS)
 i   i   1   i I  I  i I	I     I
                                        I        2    345678910       20

                                           DISSOLVED OXYGEN CONCENTRATION, mg/1
                             30
                                  Figure 4. Percent gains in dry  weight  of juvenile largemouth
                                          bass kept on an unrestricted diet of earthworms for 11
                                          to 15.5 days at 26°C,  in relation to dissolved oxygen
                                          concentrations. (After Stewart, 1962.)

-------
                                 Dissolved Oxygen Requirements of Fishes
                                                                                                     149
   In a further  experiment performed  recently  at
Oregon State  University  by R.  J.  Fisher, under-
yearling  coho  salmon  were  held at 18 °C   on an
unrestricted  diet  of  tubificid  worms  (plus  some
Daphnia). The growth rates of the salmon were much
greater than those observed at  20°C  by Herrmann,
Warren, and Doudoroff  (1962).   At high  oxygen con-
centrations  the fish increased in wet weight by about
200 to 220 percent in 18  days. The curve relating the
observed  percent weight gains to oxygen concentra-
tions below  the air-saturation  level  (Figure  5) is
not very different in shape, however, from that based
on the earlier experiments (Figure 3).  At concentra-
tions near 3 milligrams per liter the wet weight gain
in 18 days was only about 108 percent.  At concentra-
tions near 18 milligrams  per  liter,  or nearly twice
the air-saturation level, the weight gain  was slightly
greater than that observed at the air-saturation level
of  oxygen  (9.5 mg/1),  but at  concentrations  near
30  milligrams per liter, or more than  three times
the air-saturation level, the weight gain  was slightly
less than that observed  at the saturation  level.  Even
at the lowest oxygen concentration tested the fish not
only  grew fairly rapidly,  but  also  showed a  gain
in relative  fat content  and consequently a greater
percent gain in dry weight than in wet weight (Figure
5).   Wide  diurnal fluctuations of oxygen concentration
involving  nightly reductions to low levels were found
to be as  inimical to the growth of the salmon as to
the growth of largemouth bass. Coho salmon exposed
alternately to concentrations of 3 and 9.5 milligrams
per  liter  or 3 and 18 milligrams per liter for equal
periods each day  showed  weight gains in  18  days
approximately equivalent to the estimated weight gains
that would have occurred at constant oxygen concentra-
tions near 3.5 milligrams per liter  (Figure 5). The
arithmetic or geometric mean oxygen concentrations

      300 r
     250
H- 200
X
o
HJ  150
  <
  o
   100

    50

     0
         3.0-18.0 mg/l
         3.0-9.5 mg/l
                                             WET
                      _L  I  I i  I i I
        1       2    3  4 5 6 78910      20   30 40

          DISSOLVED OXYGEN CONCENTRATION, mg/l


Figure 5. Percent gains in wet and dry  weights of underyearling
        coho salmon kept on an unrestricted diet of tubificid
        worms  for 18 days at 18°C ,  in relation to dissolved
        oxygen concentrations.   Each arrow indicates  an ob-
        served weight gain of fish  subjected to diurnal  fluctu-
        ations  of dissolved oxygen between the two specified
        levels  (equally prolonged exposures to each level) and
        indicates o constant oxygen concentration at which
        nearly  the same  weight gain presumably would have
        occurred.  The lowest curve (broken line), included  for
        comparative purposes, is based  on the data plotted in
        Figure 3.
                                                      were  all well  above 5  milligrams  per liter.  At
                                                      constant concentrations equal to these means, growth
                                                      was nearly as rapid as it was at the apparently nearly
                                                      optimal constant concentration of about 18 milligrams
                                                      per liter.
                                                      EFFECTS ON EMBRYONIC DEVELOPMENT
   Salmonid embryos at various developmental stages
have been shown in the laboratory to tolerate exposures
of limited  duration  (e.g., 7 days) to dissolved oxygen
concentrations well  below 2.0  milligrams per liter
(Alderdice, Wickett,  and  Brett, 1958).  Development
is inhibited or arrested under  these  conditions,  but
upon return of the embryos to well-oxygenated water
the development can proceed to successful hatching
of larvae (i.e., sac fry). Seven-day exposures to even
lower  oxygen  concentrations have  resulted in high
mortalities of the  embryos  or in the  hatching of
structurally defective larvae.

   Continued exposure of salmonid embryos to reduced
oxygen  concentrations  well above 2 milligrams  per
liter  may  result in high or  total embryo mortality
or in retardation of embryonic development and delayed
hatching of  the  larvae,  which  may or may not be
deformed  (Garside,  1959).   High  percentages   of
successful  hatching of  steelhead trout (Salmo guird-
neri)  and  coho and chinook  salmon  occurred when
the embryos were reared from fertilization to hatch-
ing in the  laboratory at constant temperatures near
10°C    (9° to  11°C)  and  oxygen concentrations as
low as 2.5 milligrams per  liter  (Silver,  Warren,
and Doudoroff, 1963; Shumway, 1960).  Garside (1959)
reported that nearly all lake  trout embryos perished
at the temperature  of  10°C when oxygen concentra-
tions  averaged 4.2 milligrams  per  liter, but at lower
temperatures many survived to hatching even at oxygen
concentrations averaging  2.5 milligrams per liter.

   Critical or  limiting dissolved oxygen levels, at
which the  respiratory demand of salmonid embryos
is just  satisfied and below which the oxygen uptake
rates  become dependent on oxygen concentration, have
been found  to vary widely with the age of the embryos.
Critical or limiting levels well below the air-satura-
tion levels of dissolved oxygen have been reported
for all developmental  stages.   These values,   de-
termined experimentally (Hayes, Wilmot, and Living-
stone,  1951)  or  theoretically  (Alderdice,  Wickett,
and Brett,  1958), are not deemed reliable for various
reasons (Silver,  Warren, and Doudoroff,   1963).
Recent  experiments have shown that when salmon
and trout embryos are exposed to oxygen concentra-
tions below air-saturation levels throughout the period
of their development from fertilization to hatching,
not only is the hatching delayed, but also the result-
ing larvae or sac fry are smaller at hatching than
those  deriving from embryos reared at high oxygen
concentrations (Silver, Warren, and Doudoroff, 1963;
Shumway,  1960).   The size of  the  newly-hatched
sac fry has been found to be dependent on the oxygen
concentration even at concentration levels very near,
if not well  above, the air-saturation levels at tempera-
tures  near 10°C.  This  dependence  is expressed

-------
150
          ENVIRONMENTAL REQUIREMENTS OF FISHES AND WILDLIFE
over a wide range of water  velocities,  on which the
rate of  development  and the  size  of the larvae  at
hatching are likewise dependent.


   Figure 6  (after Silver,  Warren, and  Doudoroff,
1963) and Figure 7  (based  on unpublished data re-
cently obtained by D. L. Shumway at Oregon State
University) show  the  results of typical  experiments
in which steelhead trout or coho  salmon embryos
were subjected throughout  development at 9.5° or
10° C  to different, nearly  constant oxygen concen-
trations,  ranging  from  less  than  3  to about 11
milligrams per liter, at each of four different water
velocities, which ranged from 6 or 3 to  740 or 800
centimeters  per hour.  These  embryos were reared
in a special apparatus in which oxygen concentration
can  be  controlled independently of the  velocity  of
the water moving upward through porous plates on
which  the embryos rest  (Silver, Warren, and Dou-
doroff,    1963).   The dependence  of  larval size (at
hatching) on oxygen concentration even  at high con-
centration  levels  and  the   important  influence  of
water  velocity  are clearly  illustrated in Figures  6
and 7.


   It can be  concluded that  the velocity of movement
of water through streambed gravels inwhichsalmonid
eggs  are  deposited  must be high  enough  not only
to ensure delivery of enough oxygen to the redds for
supplying the total requirements of all the embryos,
but also  to  deliver sufficient oxygen  to the surface
of the  chorion enveloping  each individual  embryo.
Experiments  similar  to those  reported above  have
been  performed  recently in which some steelhead
  >-
  a:
  u
  O
  z
  iu
  <
  UJ
     20
     19
     15
     14
WATER VELOCITY
O 740 cm/hr
A 150 cm/hr
D  34 cm/hr
^   6 cm/hr
                                         I   I  I  I  I
       2         3      4     5     6   7   8  9  10 11 12
            DISSOLVED OXYGEN CONCENTRATION, mg/l

Figure 6. Mean lengths of steelhead trout larvae (sac fry) at the
        time  of their hatching,  in relation to oxygen  concen-
        trations at which embryos were reared at 9.5°C  and at
        constant water velocities. Each plotted point and curve
        represents  a result obtained at one of four different
        water velocities tested  simultaneously.  (After Silver,
        Warren, and Doudoroff, 1963.)
                                            trout embryos were embedded in large glass beads,
                                            some  in  small beads,  and  some  in a  mixture of
                                            these, whereas others were not surrounded by beads
                                            and  rested separately on the  porous  plates.   Water
                                            was   recirculated  through  each  of  these different
                                            artificial  redds  at  equal rates.   The availability of
                                            oxygen to the  embryos at a given oxygen concen-
                                            tration was nevertheless expected  to vary with the
                                            estimated mean velocity of  the  water in the voids
                                            among the various  solid components of the artificial
                                            redds (i.e., the mean "pore velocity,"whichincreased
                                            as the porosity decreased).   The  results indicated
                                            that  the availability of oxygen varied indeed  and in
                                            a  manner generally consistent with the  data  on the
                                            influence of ambient water  velocity differences pro-
                                            duced without  the use of beads by varying the water
                                            recirculation or discharge rates only. That increas-
                                            ing  the  velocity  of water  around  embryos by em-
                                            bedding  them  in glass beads while maintaining the
                                            same water discharge rate can result in an increase
                                            of the  size of newly hatched  coho  salmon  larvae
                                            had  been  demonstrated  earlier by  Shumway  (1960).

                                               The  relative efficiencies  of   conversion  of yolk
                                            to embryonic  tissue in coho  salmon are impaired at
                                            moderately low oxygen concentrations and water velo-
                                            cities (Shumway, 1960).  However, inasmuch as there
                                            is insufficient  evidence that, under the same environ-
                                            mental conditions, the yolk conversion  efficiency of
                                            sac  fry  also is seriously impaired and there is some
                                            evidence that  it may not be  impaired materially in
                                            steelhead trout fry, the importance of  the reduction of
                                            conversion  efficiency  observed  during  embryonic
                                            development is still uncertain. Only  a small portion
                                            of the  yolk is utilized  during development prior to
10
 9
 8
 7
                                                          01
                                                          6
                                             e>
                                             in
                                                          a.
                                                          o
WATER VELOCITY
 O 800 cm/hr
 A 100 cm/hr

 D 12 cm/hr
 ^7  3 cm/hr
                                                                                                      1  i  I 1  i
                                                               2       3     456789 101112
                                                          DISSOLVED OXYGEN CONCENTRATION, mg/l
                                            Figure 7. Mean dry weights of coho salmon larvae (sac fry with
                                                    yolk  sacs removed) at the time of their hatching, in
                                                    relation to oxygen concentrations at which embryos were
                                                    reared at 10°C and at  constant water velocities.  Each
                                                    plotted point and curve represents a result obtained at
                                                    one  of four  different  water  velocities tested simul-
                                                    taneously.
                                                                                                     GPO 816-361—6

-------
                                  Dissolved Oxygen Requirements of Fishes
                                               151
hatching.   Inhibition  of  the  growth  of  sac fry of
Atlantic salmon at reduced oxygen concentrations has
been reported  by Nikiforov  (1952), but the influence
of  oxygen concentration on the growth of salmonid
larvae  needs further investigation, with attention  to
the  efficiency  of yolk utilization  for  growth, which
efficiency  could well be  impaired when growth  is
inhibited.
 EFFECTS  ON  MOVEMENTS  (AVOIDANCE  REAC-
 TIONS)
    The ability of fishes to detect and avoid low oxygen
concentrations  under experimental  conditions  in  the
laboratory has been repeatedly demonstrated (Shelford
and Allee,  1913; Jones, 1952;  Whitmore, Warren,
and Doudoroff,   1960;  Hoglund, 1961).  Whitmore,
Warren,  and Doudoroff (1960)  found  that juvenile
Chinook salmon showed marked and prompt  avoidance
of  reduced  oxygen concentrations as  high as  4.5
milligrams per  liter at summer temperatures.  The
behavior  of coho salmon  was  somewhat erratic
and their avoidance of  low oxygen concentrations less
pronounced than  that of the chinook salmon, but there
was apparently some  avoidance  of concentrations as
high as 6.0 milligrams per liter. Juvenile largemouth
bass  and bluegills markedly avoided  concentrations
near  1.5  milligrams per liter, but showed little or
no avoidance of concentrations near  3.0 and 4.5 milli-
grams per liter; only the bass showed any  avoidance
of the latter concentration.
   The very prompt avoidance by some of  the fish,
especially chinook salmon, of reduced oxygen concen-
trations  well above those known to  be lethal to the
fish  or to elicit visible symptoms of acute  respira-
tory distress was not deemed  ascribable  entirely
to mere stimulation or increase of the activity of the
fish  caused by oxygen  deficiency.  Jones (1952) had
suggested that latter explanation  for his own  ob-
servations  on the  avoidance by some fish of reduced
oxygen concentrations,  but  it was found  not to apply
to the  more recent observations considered above.
Hoglund  (1961), who was  aware of the latter results,
on the basis of his  own experiments also concluded
that  "oxygen is a non-directive stimulus to fish."
While  maintaining  that there is no convincing pub-
lished  evidence that oxygen  "acts as a directive stimu-
lus," however, he offers no other satisfactory explana-
tion  of the quantitative results reported by Whitmore,
Warren, and Doudoroff (1960),  which indicate  that
even moderate oxygen deficiency, insufficient to pro-
duce acute  respiratory distress,  can act  as  such
a  stimulus  under some  experimental conditions at
least.   Until sufficient reasons are found  for dis-
counting the latter seemingly  sound  statistical evi-
dence,  the conclusion that some fish can show prompt
directional  changes  of  movement upon encountering
oxygen-deficientwater shouldnot be lightly dismissed.
It  is noteworthy that quite different methods have
been employed in  the investigations  that have led to
different conclusions concerning the nature of the
a'/oidance reactions observed.
INFLUENCE OF CARBON DIOXIDE

    Reduced oxygen concentrations in both natural and
polluted waters  normally are associated with elevated
concentrations  of free  carbon dioxide, which have
been  found to reduce the resistance of fish to oxygen
deficiency (Alabaster,  Herbert, and Hemens,  1957).
In most of the  experiments on the effects of reduced
oxygen  concentrations mentioned herein, the concen-
trations  were  reduced  by means of nitrogen gas
bubbled through the water, so  that  an increase  of
carbon  dioxide  concentration was  not involved as a
complicating  factor.  Basu (1959) found that  in the
presence of moderate concentrations of carbon dioxide
the active oxygen uptake rates of  fish are markedly
reduced, especially at oxygen concentrations near the
lethal levels.   At  any  constant  level  of dissolved
oxygen,  the  logarithm of the  active  rate of oxygen
consumption  usually decreased rectilinearly with the
concentration of carbon dioxide.  It should be noted,
however,  that the  fish  had been recently placed  in
the experimental media. The data of McNeil (1956)
indicate that the adverse effects of moderate concen-
trations of free carbon  dioxide  on the tolerance  of
low oxygen concentrations  by resting  fish are trans-
ient,  the  fish evidently  becoming acclimatized very
soon  to these carbon dioxide  concentrations.   Con-
centrations up to about  40  milligrams per liter had
little  effect in experiments  with juvenile coho salmon
when  the carbon dioxide  content of the  water was
increased  to these  levels and  its  oxygen content
reduced gradually  (as  they usually would be  under
natural  conditions). Also, coho  salmon placed in water
with a high free carbon dioxide  content  in  sealed
bottles were better able to reduce the oxygen concen-
tration  in the  medium to  a  lower  level when the
initial dissolved oxygen content was high,  permitting
acclimation to  the high  carbon dioxide levels, than
when  the  initial oxygen  content was lower. Adverse
effects of carbon dioxide on active oxygen consumption
rates, swimming performance, etc.,  possibly also
diminish or disappear rapidly with acclimation, so that
under natural conditions the influence of carbon dioxide
concentrations that  are  likely to  occur  in waters
with moderately reduced oxygen concentrations may
usually  be negligible. In recent experiments at Oregon
State  University, M.  L. Dahlberg found that the  maxi-
mum  sustained  swimming  speeds (mean)  of large-
mouth bass  and coho  salmon at reduced  dissolved
oxygen levels were not affected or were  only moderate-
ly affected by elevated free carbon dioxide concen-
trations up to 40 milligrams per liter, to which the
fish had been acclimatized overnight.  Concentrations
near  20 milligrams per liter had almost no  effect
on the performance even of  the salmon, which proved
more  susceptible than the bass to  higher concen-
trations.  Much higher free carbon dioxide concen-
trations  do not occur  ordinarily in  stream waters
receiving organic wastes where dissolved oxygen con-
centrations are not exceedingly reduced.

   The  reduction of the resistance of fish to low oxygen
concentrations that has been observed upon addition
to their medium of mineral  acids  (which liberate
carbon  dioxide from bicarbonates present in natural
waters)  sometimes  has  been  ascribed erroneously
to the influence of hydrogen  ions.  This error appears

-------
152
ENVIRONMENTAL REQUIREMENTS OF FISHES AND WILDLIFE
even  in  recent literature.  For example,  Bishop,
(1950),  in discussing  the least tolerable  oxygen
concentration  for fish as  a  function  of  pH, cites
data of Wiebe et al.  (1934).  These data, presented
graphically, indicate that at reduced pH levels even
as high as 6.0, bluegills are unable to extract oxygen
from  the water  (at 18°  to 25° C) when the oxygen
concentration is  7 milligrams per liter or less. This
cannot be true, of course, for bluegills tolerate vari-
ations of pH over a wide range. Doudoroff and Katz
(1950) and Doudoroff (1957) have pointed out that the
harmful  effects of  carbon dioxide  solutions are not
attributable to  their reduced pH and that injurious
amounts  of carbon  dioxide  can  be liberated by acids
added to natural waters without reducing the pH of
the water  to demonstrably harmful levels.  McNeil
(1956) presented  convincing evidence that the effects
of free carbon dioxide on the  dissolved oxygen re-
quirements of coho salmon and bluegills  are not
ascribable to changes  of pH of the water.  Reduction
of the pH  of water to some unusually  low nonlethal
levels without increasing the tension of carbon dioxide
(which was driven out by aeration) had little or no
influence on the  ability of the  fish to extract oxygen
from  the water.  Hoglund (1961) found that the avoid-
ance  reactions  of fishes to increased carbon dioxide
concentrations  also  are responses not to  reduced
pH, but to carbon dioxide per se.

   It  has long  been known  that fish are quite sensi-
tive and  responsive  to differences of carbon dioxide
concentration alone, marked avoidance  reactions  to
elevated concentrations having been reported.  Hoglund
(1961), who presented additional evidence,  has briefly
reviewed the pertinent earlier literature.  Unpublished
results of experiments at Oregon  State University with
juvenile  chinook  salmon, similar to the experiments
on reactions to reduced oxygen concentrations alone
(Whitmore etal.  1960),indicatedthat,athightempera-
tures at least, the increase of carbon dioxide concen-
tration that is to be expected in waters whose oxygen
concentrations are reduced by natural processes could
well be an important factor contributing to avoidance
of such  water  by salmon.  It is apparent, however,
that the  reactions of the fish to reduced oxygen con-
centrations per se  may not yet be disregarded  as
being of  minor importance.  There is  evidence that
oxygen  dificiency  can be the  chief  or dominant
stimulus to which fish respond  when confronted with
water in  which  the reduction of dissolved oxygen has
been  accompanied  by  a  normal  increase  in free
carbon dioxide.

PRACTICAL AND ECOLOGICAL SIGNIFICANCE OF
EXPERIMENTAL RESULTS

   The problems involved in  the establishment of
sound criteria or  standards for  dissolved  oxygen
for the adequate  protection of  valuable fish popula-
tions  through waste  disposal control have been dis-
cussed by  Doudoroff (1960) and by Fry  (1960). Since
oxygen concentrations in waters  polluted with organic
wastes have been found usually to vary widely,  so
that average concentrations greatly exceed the mini-
mum  levels, one of the questions that has been raised
(Doudoroff, 1960) is to what extent the usual fluctua-
tions  of  oxygen concentrations should be considered
in prescribing appropriate standards.
                                     The Aquatic Life Advisory Committee of the Ohio
                                 River  Valley  Water  Sanitation  Commission  (1955)
                                 tentatively recommended  the following criteria or
                                 standards, among others, for the protection of warm-
                                 water fish populations:

                                       "The  dissolved   oxygen content of warm-
                                    water  fish  habitats  shall be  not less  than
                                    5 ppm  during  at  least  16  hours  of  any 24-
                                    hour  period.    It   may be  less  than 5  ppm
                                    for  a period  not   to  exceed  8 hours within
                                    any  24-hour period, but at  no time shall the
                                    oxygen  content  be  less than 3  ppm.  To sus-
                                    tain a coarse fish population the dissolved oxygen
                                    concentration  may  be less  than  5  ppm  for
                                    a  period of  not  more  than  8  hours out of
                                    any  24-hour period, but at  no time shall the
                                    concentration be below 2 ppm."

                                 The seemingly reasonable assumption is implied that
                                 intermittent exposure of fish in their natural environ-
                                 ment to nonlethal low oxygen concentrations  during
                                 a  large portion  of each  24-hour  day has little ad-
                                 verse  effect on the fish if relatively high  concentra-
                                 tions  (above 5 mg/1) predominate.   This implied
                                 assumption is  not  supported by  the results of the
                                 herein reported experiments on the effects of diurnal
                                 fluctuations of dissolved  oxygen  on  the  growth  of
                                 fish.   Although the  fish that were subjected to wide
                                 fluctuations  of oxygen concentration derived some
                                 benefit from their  prolonged daily exposure to high
                                 concentrations, the inhibitory influence of the re-
                                 curring, intermittent exposure to low concentrations
                                 on their growth  was nevertheless very pronounced.
                                 These fish did little better than those exposed con-
                                 tinuously to the same low oxygen  concentrations,
                                 and they usually did   as  poorly,  or  not as well, as
                                 they  would  have done  at constant  concentrations
                                 only  about  1 milligram per liter  higher  than these
                                 mean  daily minima.   It  now appears that complex
                                 and not easily enforceable water quality standards
                                 pertaining to dissolved oxygen, such as those pro-
                                 posed  by  the  Aquatic  Life  Advisory  Committee,
                                 probably  are not justifiable.  Simpler criteria ap-
                                 parently can be at least as satisfactory and defensible.

                                    The growth rates  of largemouth  bass and coho
                                 salmon in the  laboratory were  considerably reduced
                                 even at nearly  constant reduced oxygen concentrations
                                 averaging  about  5   milligrams  per liter  and more.
                                 Although reduction of  dissolved oxygen from 90 per-
                                 cent to 50 percent of the air-saturation value usually
                                 had a  somewhat  more striking  effect on the growth
                                 of largemouth  bass (at 25°C) than on the growth of
                                 coho  salmon  (at 18°  to 20° C), the  effect of such a
                                 reduction of dissolved oxygen on the sustained swim-
                                 ming speed of  bass was much less pronounced than
                                 the effect on  the swimming speed of coho salmon.
                                 In  view of the ability of the bass to remain nearly
                                 as active at  moderately  reduced oxygen  tensions
                                 as at  higher  tensions, and their relatively great
                                 tolerance of low oxygen tensions, the pronounced effect
                                 on their growth of a moderate reduction of dissolved
                                 oxygen is interesting  and somewhat surprising.  Can
                                 one  safely conclude from the results of the growth
                                 experiments that bass  production in natural situations
                                 is  materially  impaired  at reduced  oxygen concen-

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                                 Dissolved Oxygen Requirements of Fishes
                                               153
trations  near 5  milligrams per  liter?   Is  it safe
to conclude that when almost unimpaired  fish pro-
duction is the objective,  it is  at  least as important
to maintain dissolved oxygen concentrations near the
air-saturation level in waters  inhabited by the bass
as to maintain such concentrations in waters inhabited
by  coho  salmon?   These questions are as yet un-
answered.

   The  ecological  significance  of all  the  various
reported observations made in the laboratory admit-
tedly is  not yet  clear.  Oxygen concentrations that
are avoided by fish under some experimental conditions
are necessarily avoided likewise under natural condi-
tions, especially in situations where  the   transition
from high to low  concentrations  is  very gradual,
the transitional zone extending over a long distance.
Swimming  speeds and developmental rates that are
essential to survival and unimpaired success of fish
in  their  natural  environments,  as  well  as larval
sizes that must be  attained by the time of hatching
or of complete yolk absorption, are unknown. Pre-
sumably, they can  all be determined experimentally,
but their determination will  not be a simple task.


   The swimming  capability of individual fish living
at high oxygen concentrations in their natural environ-
ment probably can be impaired in varying degrees
by  some  operative  or mechanical means  without
seriously injuring  them  otherwise.   The minimum
degree  of impairment  of swimming performance
that results in increased mortality or reduced growth
rates of these fish  under natural conditions  pre-
sumably  can  be  established  by  comparing their
mortality and growth rates with  those of controls
placed in the same or similar natural environments.
This information would indicate about how much im-
pairment  of  swimming performance caused  by re-
duction of the dissolved oxygen  concentration could
result  in impairment of  survival and  growth.  It
must be recognized, however, that different kinds
of swimming  performance may not be  equally  or
correspondingly affected by reduction of oxygen con-
centration.   This  could  seriously  complicate the
interpretation of the experimental results.

   The survival in stream-bed gravels  of salmonid
larvae hatched and reared at different oxygen concen-
trations  and water  velocities can be studied in the
field (Coble, 1961; Phillips and Campbell, 1962) and
in the  laboratory.  Such studies are now in progress
in Oregon. There are sound reasons for believing
that the  relatively  small and weak larvae,  or sac
fry, that  succeed  in hatching at  low oxygen  con-
centrations may be unable to survive to successful
emergence from  the  overlying gravel under natural
circumstances, even  though they may do well at the
same  concentrations under otherwise favorable lab-
oratory conditions.  Simulation of the more rigorous
natural conditions  in the laboratory, where  oxygen
concentrations and water velocities can be accurately
controlled throughout the period of embryonic develop-
ment and  thereafter, is  deemed essential  to  full
understanding of the fate of embryos and fry in natural
redds  with interstitial water  of  impaired quality.
   The reduced oxygen concentration at which incipient
impairment of the growth of fish occurs under natural
conditions probably depends on the availability of food,
which may  itself  be the major factor limiting growth
rates.  This "critical"  concentration (for growth im-
pairment) may well depend also on the rate at which
energy must be expended by  the  fish in seeking and
capturing the available food,  while also escaping
enemies, etc.  The appetite of the fish, or their activity
that presumably is necessary for food procurement, or
both, evidently must be  reduced when available oxygen
becomes insufficient for supporting all metabolic pro-
cesses at normal levels.

   Although  the  growth  of  fish  that  were  kept
on  an unrestricted  diet in the laboratory  where an
unlimited amount  of food could be found and ingested
by them with minimum effort was materially impaired
by  moderate  reduction of oxygen concentration,  the
growth even  at very low  concentrations often  was
quite rapid.   The greatest observed growth rates of
juvenile largemouth bass and coho salmon at oxygen
concentrations near  2  and 3  milligrams per liter,
respectively,  doubtless were greater than the growth
rates  of  these fish in  many  natural habitats where
oxygen is abundant but  the food supply is limited.
When  supplied only   with the limited amount of food
that is obtainable by fish in any one of these natural
habitats, inactive fish in the laboratory perhaps would
concume all of this food and grow about as rapidly at
moderately  low oxygen concentrations as at higher con-
centrations.  Such a result, however, would not signify
that impairment of growth of more active fish in the
natural habitats would not occur upon reduction of the
oxygen concentration to the same low levels. Without
drastic reduction of feeding  activity, the maximum
possible oxygen  uptake rate  under these conditions
could well become insufficient for digestion and as-
similation of the normal food ration.  Thus, the rates
of food intake  and growth could be reduced markedly
through reduction of appetite or of success in finding
and capturing food, or of both.

   A  satisfactory  laboratory model for studies of the
dissolved  oxygen requirements  of  fish,  which is
directed toward reliable estimation  of critical con-
centrations  at  which  incipient impairment  of growth
would occur in a given natural environment, obviously
cannot be a simple one.   Evidently it must combine
the food ration normally obtainable under  favorable
dissolved oxygen conditions in the natural environment
with enforced  activity  approximately  equivalent to
the spontaneous  or  other activity  that  occurs  and
presumably   is essential  for  survival and normal
feeding under natural conditions.  Given the  mean en-
vironmental temperature, the mean daily food ration,
and the normal growth  rate of the fish in the natural
environment, one  should be able to reproduce these
in the laboratory, forcing the fish to swim against a
moderate  current, so as to necessitate just the ap-
propriate  amount  of energy expenditure through sus-
tained activity.   The minimal reduction of  oxygen
concentration  that would result in  appreciable im-
pairment  of the  appetite  and growth of fish in the
laboratory under conditions predetermined in accord-
ance  with the proposed scheme could  reasonably

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154
ENVIRONMENTAL REQUIREMENTS OF FISHES AND WILDLIFE
be  assumed  to  correspond  approximately  to  the
minimal reduction that would impair the growth of the
fish in the natural environment on which the model was
based. The "critical" oxygen concentration for impair-
ment of growth of juvenile largemouth bass, evaluated
in this  manner, could often turn out to be well below
the air-saturation levels and below the corresponding
critical concentrations for juvenile coho salmon in
their  typical   stream  habitats,  where  the salmon
usually are much more active than bass in sluggish
streams.   The critical concentrations,  however, at
which the growth rates of a given fish species become
concentration-dependent in  different  environments
and seasons probably  vary widely with temperature,
the abundance and availability of food, water velocity,
etc.


    The growth rates of various fishes at  recorded
temperatures in representative natural habitats have
been  evaluated.  Unfortunately, reliable  information
                                 on the  rates of food consumption by the fish and even
                                 proven methods for the evaluation of these rates under
                                 natural  conditions are  lacking.   New  methods are
                                 being  developed, however (Darnell and  Meierotto,
                                 1962).    Refined evaluations  of  food  consumption
                                 rates presumably will have to be based on numerous
                                 measurements  of  stomach contents, together with
                                 accurate determinations of digestion rates, which are
                                 known  to vary with  the  quality and quantity of food
                                 consumed.

                                    The  over-all research program suggested above
                                 clearly is not an easy undertaking. However, inasmuch
                                 as the  suggestions  apply not  only  to the study of
                                 dissolved oxygen requirements, but also to the study
                                 of other water  quality  requirements of fishes,  the
                                 effort required for an effective attack on the outlined
                                 problems is  deemed fully  justifiable.   The past
                                 research summarized in this paper  is considered
                                 to be  only  a  necessary first step toward  clear
                                 definition and  eventual  solution of these  problems.
                                              REFERENCES
 Alabaster, J. S., D.  W. M. Herbert, and J. Hemens.
 1957.   The survival  of rainbow  trout  (Salmo guird-
 nerii  Richardson)  and perch (Perca fluviatilis  L.)
 at  varius  concentrations of  dissolved  oxygen and
 carbon  dioxide.   Ann.  Appl.  Biol.,  45: 177-188.

 Alderdice,  D.F.,  W.  A.  Wickett,  and  J. R. Brett.
 1958.    Some  effects of temporary exposure to low
 dissolved  oxygen  levels  on  Pacific  salmon  eggs.
 Jour.  Fish Res. Bd. Canada, 15: 229.250.

 Aquatic Life  Advisory Committee.   1955. Aquatic
 life water  quality criteria.   Sewage and Industrial
 Wastes, 27:  321-331.

 Basu, S. P. 1959. Active respiration of fish in relation
 to ambient concentrations of oxygen and carbon dioxide.
 Jour.  Fish. Res. Bd.  Canada,  16: 175-211.

 Bishop, D. W, 1950.  Respiration and metabolism.
 In:  Comparative  animal physiology (C.  L. Prosser,
 ED.).    W.  B. Sannders Co.,  Philadelphia, pp. 209-
 289.

 Blazka,  P.  1958.  The anaerobic metabolism of fish.
 Physiol. Zool., 31: 117-128.

 Coble, D. W.  1961.   The influence of environmental
 conditions in  redds on the survival of salmonid em-
 bryos.    Trans. Amer.  Fish.  Soc.,  90: 469-474.

 Darnell, R. M., and R. R. Meierotto.  1962.  Deter-
 mination of feeding  chronology  in fishes.   Trans.
 Amer. Fish. Soc., 91:313-320.
Davis,  G.  E.,  J.  Foster,  C.  E. Warren, and P.
Doudoroff.  1963.  The  influence of oxygen concen-
tration on  the  swimming performance  of  juvenile
Pacific  salmon  at  various  temperatures.   Trans.
Amer. Fish. Soc. 92:  111-124.
                                 Davison,  R. C., W. P. Breese,  C. E. Warren, and
                                 P.  Doudoroff.   1959.  Experiments on the dissolved
                                 oxygen requirements of cold-water fishes.  Sewage
                                 and Industrial Wastes, 31:  950-966.


                                 Doudoroff,  P.   1957.   Water  quality requirements
                                 of  fishes and  effects of toxic substances.  In:  The
                                 physiology  of  fishes  (M.  E. Brown,  Ed.),  Vol.  2,
                                 Behavior.   Academic Press, Inc., New York.  pp.
                                 403-430.

                                                  1960.  How should we  determine
                                 dissolved oxygen  criteria  for  fresh water  fishes?
                                 In:  Biological  problems in water pollution (Trans-
                                 actions  of  the 1959  seminar).   Technical Report
                                 W60-3, Robert  A. Taft Sanitary Engineering Center,
                                 U.  S. Public Health  Service,  Cincinnati,  Ohio. pp.
                                 248-250.

                                 Doudoroff,  P., and M. Ka^z. 1950.  Critical review
                                 of  literature on the toxicity of  industrial wastes and
                                 their  components to  fish.   I.  Alkalies,  acids, and
                                 inorganic  gases.    Sewage and  Industrial Wastes,
                                 22: 1432-1458.

                                 Ellis, M. M.   1937.   Detection and measurement of
                                 stream pollution.   Bull.   No. 22,  U, S.  Bureau of
                                 Fisheries:  Bull. Bur. Fish., 48: 365-437.

                                 Fry,  F. E.  J.   1947.  Effects of the environment  on
                                 animal activity.  Univ. Toronto  Studies, Biol. Ser.
                                 No. 55 (Pub. Ontario Fish. Res.  Lab. No. 68). 62 pp.

                                                 1957. The  aquatic respiration of fish.
                                 In: The physiology of fishes (M. E. Brown,  Ed.), Vol.
                                 1,  Metabolism.   Academic Press, Inc., New York.
                                 pp. 1-63.

                                               1960.  The oxygen  requirements of fish.
                                 In:   Biological  problems in water pollution (Trans-

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                                 Dissolved Oxygen Requirements of Fishes
                                              155
actions  of  the 1959  seminar).   Technical Report
W60-3, Robert A. Taft Sanitary Engineering Center,
U.  S.  Public Health Service, Cincinnati,  Ohio.  pp.
106-109.


                1961.  Personal communication and
unpublished  account  of recent  experimental results
obtained by  D. W.  Coble, received  in  July, 1961.

Garside,  E.  T.   1959.    Some  effects of oxygen in
relation to temperature on the development of lake
trout embryos.  Canadian Jour. Zool., 37:  689-698.

Graham, J. M.  1949.  Some effects of temperature
and  oxygen pressure on the metabolism and activity
of the speckled trout, Salvelinus fontinalis. Canadian
Jour. Res., D, 27:  270-288.

Hayes, F. R., I.  R. Wilmot, and D. A.  Livingston.
1951.   The  oxygen consumption of the salmon egg
in relation  to development and activity.  J. Exper.
Zool., 116:  377-395.

Herrmann, R. B., C. E. Warren, and P.  Doudoroff.
1962.  Influence of oxygen concentration on the growth
of juvenile coho salmon.   Trans. Amer.  Fish. Soc.,
91:  155-167.
Hoglund, L. B. 1961. The reactions of fish in concen-
tration gradients.  Fishery Board of Sweden, Insti-
tute of Freshwater Research, Report No. 43.  147 pp.

Job, S. V., 1955. The oxygen consumption of Salvelinus
fontinalis.   Univ.  Toronto Studies,  Biol.  Ser.  No.
61  (Pub.  Ontario Fish. Res.  Lab. No. 73).  39 pp.
Jones, J. R. E. 1952. The reactions of fish to water
of low  oxygen concentration.   Jour. Exp. Biol., 29:
403-415.

Katz, M.,  A. Pritchard,  and  C.  E. Warren.  1959.
Ability  of some salmonids and a centrarchid to swim
in water of reduced oxygen content.  Trans. Amer.
Fish. Soc., 88: 88-95.
McNeil, W. J.  1956.  The influence of carbon dioxide
and pH on the dissolved oxygen requirements of some
fresh-water fish. M.Sc. Thesis, Oregon State Univer-
sity Library, Corvallis, Oregon.

Moss, D. D.,  AND D.  C. Scott.   1961.  Dissolved
oxygen requirements of three species of fish.  Trans.
Amer. Fish. Soc., 90:  377-393.

Nikiforov,  N. D.   1952.   Growth and respiration of
young  salmon  at  various  concentrations  of  oxygen
in water,  (in Russian) Doklady Academii Nauk SSSR
(C. R. Acad. Sci. U.S.S.R.), 86: 1231-1232.

Phillips, R. W., and  H.  J.  Campbell.   1962.  The
embryonic  survival of coho  salmon and steelhead
trout  as influenced by some environmental conditions
in gravel beds.   In:   Fourteenth  annual  report of
the Pacific Marine Fisheries  Commission for the
year 1961.  Pacific Marine Fish. Comm., Portland,
Oregon,  pp. 60-73.
Shelford, V. E., and W.C. Allee. 1913.  The reactions
of fishes to gradients of dissolved atmospheric gases.
Jour. Exp. Zool., 14: 207-266.

Shepard, M. P.   1955.   Resistance  and tolerance of
young speckled trout (Salvelinus fontinalis) to oxygen
lack,  with special reference  to low  oxygen accli-
mation.  Jour. Fish Res. Bd.  Canada, 12:  387-446.

Shumway, D. L.  1960.  The influence of water velocity
on the development of salmonid embryos at low oxygen
levels. M.Sc. Thesis, Oregon State University Library,
Corvallis, Oregon.  49 pp.

Silver,  S. J.  1960.  The influence  of water velocity
and dissolved oxygen on the development of salmonid
embryos.   M.Sc. Thesis,  Oregon  State University
Library, Corvallis, Oregon 50 pp.

Silver,  S. J.,  C. E. Warren, and P. Doudoroff.   1963.
Dissolved oxygen requirements of developing steelhead
trout and chinook salmon embryos at different water
velocities.  Trans.  Amer. Fish. Soc.,  92:  327-343.

Stewart, N. E.  1962. The influence of oxygen concen-
tration  on the  growth of juvenile largemouth bass.
M.Sc. Thesis, Oregon State  University Library, Cor-
vallis, Oregon.  44 pp.


Tarzwell,  C.  M.  1957.  Water quality  criteria for
aquatic  life.    In:   Biological problems  in  water
pollution  (Transactions of the 1956 seminar), Robert
A.  Taft  Sanitary Engineering Center, U. S. Public
Health Service, Cincinnati, Ohio. pp. 246-272.


Townsend, L. D., and D. Earnest. 1940.  The effects
of  low   oxygen  and other  extreme   conditions on
salmonoid fishes.   Proc.   Pacific Sci. Congress,
Pacific  Sci. Assoc., 6th Congr., 1939, 3:  345-351.

Whitmore,  C.  M, C. E. Warren, and  P. Doudoroff.
1960. Avoidance reactions of salmonid and centrarchid
fishes to low  oxygen concentrations.   Trans. Amer.
Fish. Soc., 89: 17-26.

Wiebe,  A. H.,  A. M.  McGavock, A.  C.  Fuller, and
H.  C. Markus.   1934.  The ability  of fresh-water
fish to  extract oxygen  at  different hydrogen-ion
concentrations.  Physiol. Zool., 7: 435-448.


Winberg,  G. G.  1960.  Rate of metabolism and food
requirements  of  fishes.   (Originally published in
Russian  in: Nauchnye  Trudy Belorusskovo Gosudar-
stvennovo  Universiteta Imeni V. I. Lenina, Minsk,
253 pp., 1956). Translation Series No. 194, Fisheries
Research Board of Canada (Nanaimo, B. C.).  202
pp. ± 32 tables.

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156
ENVIRONMENTAL REQUIREMENTS OF FISHES AND WILDLIFE
        THE ENVIRONMENTAL REQUIREMENTS OF CENTRARCHIDS WITH SPECIAL REFERENCETO

                     LARGEMOUTH BASS, SMALLMOUTH BASS, AND SPOTTED BASS

                                          George W. Bennett *
   The family  Centrarchidae  includes  many of the
so-called pan fishes, as well as the larger members
of the family that used to be known as black bass.
As  these  fish  are never black (with the exception
of smallmouth  fry),  the name black bass has been
discarded.    This is unfortunate  only  because the
designation  "black"  furnished a definite separation
between the Centrarchid basses and the true basses
(Serranidae).

   It  is  safe to say that in  North  America there
is a Centrarchid bass for every type of water warmer
than that  suitable for  trout.   These fish are found
in waters with summer temperatures ranging from
those of the warmest natural  waters in the southern
states  to  those of the  glacial lakes along the Ca-
nadian border.   Most of the species of bass are very
hardy as adults,  very sporting to catch,  and  among
the most  "intelligent"  of fresh-water  fishes.  For
these reasons,  they  have been widely distributed and
are  frequently found in  small numbers, at least,
in almost every type of aquatic habitat.

   Bass are seldom caught in large numbers, although
there was a substantial commercial fishery for them
in the  late  19th and  early  20th  centuries.  For
example, Bartlett (1) reported that in the year 1907,
three men  fishing in the Illinois River at the mouth
of a  slough  running out from one of the backwater
lakes in the  Meredosia region (Morgan Co., Illinois)
took 375 largemouth bass ranging in weight from one-
half  to 3 pounds  in 3 hours.  This is an average rate
of about 42 bass per man-hour.  This  rate of catch
must be considered  remarkable because the average
rate  of  catch  today  in  heavily fished waters  is
probably less than  one-tenth-of-a-pound  per hour.

SPAWNING HABITS AND TEMPERATURES

   A  great  deal  of  information has  been published
on the spawning habits of bass  and other centrarchids,
particularly those that have been raised in fish hatch-
eries.   Nesting  behavior is  well known (5).  The
male  clears a circular bed, or redd, on the bottom
of a  lake  or stream.  When  the nest is completed,
a female ready to spawn will enter the nest and spawn
with the male.  The fertilized eggs sink to the bottom
of the nest and become attached to gravel,  rubble,
sticks, roots, and other material that may be within
the nest boundaries.

   Kelley (13) reported from 5,000 to 82,000fertilized
eggs per  nest  for largemouth bass; Car lander  (7)
reported 2,000 to 109,000 eggs.   Not  all of these
eggs  hatched, but Lamkin (15)  stated that he took
                                 as  high  as  10,000  fry from  a single nest and as
                                 low as 2,000 to 3,000.  Lamkin's observations were
                                 made of hatchery ponds.

                                    Largemouth,  smallmouth, and spotted bass have
                                 been  reared  in hatchery  ponds for  many  years;
                                 thus  a good deal of information is available on all
                                 aspects of  nest  building, spawning, hatching, and fry
                                 development.   According to Lamkin (15), when  the
                                 water  reached  56°F   (13.3° C),  largemouth bass
                                 began nest  building.  Actual spawning did not take
                                 place, however, until the waters were about  66° F
                                    The incubation period for largemouth bass ranges
                                 from 48 to 72 hours, depending upon the water tempera-
                                 ture. The fry rise from the nest, that is, they resorb
                                 their yolk sacs  and swim actively in 6 to 8 days
                                 after hatching.  Kramer and Smith (14) reported that
                                 in  natural  waters  largemouth  fry  rose from  the
                                 nest in  5 to  8 days.  These investigators recorded
                                 the percentage of nests constructed on various bottom
                                 materials:   In East Slough  (Minnesota) in  1958,  73
                                 percent  of the nests were constructed in the  roots
                                 of water shield or water  lily, 10 percent on needle
                                 rush, and  the rest on fibrous  debris  or  on sand.


                                    The  small largemouth  bass  reached lengths  of
                                 32.5 millimeters 26 to 31 days after hatching (14).
                                 Their early diet  consisted of a variety of entomos-
                                 traca and small  aquatic  organisms.  Fish appeared
                                 in the  diet when  the bass  were 20 millimeters long.

                                    Hatchery-reared largemouth and smallmouth fin-
                                 gerlings have been widely  distributed  in lakes and
                                 streams beyond  their original range.  Spotted bass
                                 are  somewhat less common, but in streams where
                                 they are indigenous, they  are found in intermediate
                                 temperature zones between zones in which largemouth
                                 and  smallmouth  bass  are found.  They  seem to be
                                 better  suited to  certain types of aquatic conditions
                                 than either largemouths or smallmouths. For example,
                                 both largemouth bass and smallmouth bass have been
                                 stocked in the streams of  southern Ohio for the past
                                 40  years (23).   In this location spotted bass have
                                 never been stocked, yet the spotted bass is the domi-
                                 nant fish in these  lowland streams.

                                    The spawning  temperature of  the spotted bass is
                                 64° F  (17.8° C)   (10), which is about 2°F lower than
                                 for  the  largemouth bass  and 2°F  higher than that
                                 for  the  smallmouth.  In  many  other  respects  the
                                 spotted bass is intermediate between the largemouth
                                 and  the smallmouth; this is true even in its appear-
* Head, Aquatic Biology Section, Illinois Natural History Survey, Urbana, Illinois.

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                           The Environmental Requirements of Centrarchids
                                             157
ance, because it seems to have certain characteristics
that are similar to those of the smallmouth and others
that are similar to those of the largemouth.

   The spawning temperature of the smallmouth bass
is about 62°F (16.7°C) (22),  or  4°F or more lower
than that for  the largemouth.   This means that in
lakes where  both smallmouth and largemouth bass
are present the  smallmouth should spawn from  2
days to 2 weeks earlier than the largemouth.

   Many observations of the effects of changing water
temperatures on the developing eggs and embryos have
been made by hatchery personnel.  Under extreme
weather conditions, temperatures in hatchery ponds
may rise quite rapidly for as much as 13°or 14°F.
Tester (22) records the death of  embryos as a result
of a 2-day temperature  rise from  61° to  73.5 °F
(16.1°  to 23.1°C).  Drops of temperature will also
cause loss of nests, partly because the parents abandon
them.  Lydell (16) reported a loss of eggs when the
water temperature dropped from 65°F to 45°F (18.4°
to 7.2C).  Meehan (17) observed that the smallmouth
bass abandoned their  nests when water temperature
dropped from  58° to 48°F (14.4° to 8.9°C).  Kramer
and Smith (14) reported the death of largemouth bass
embryos when water temperature dropped from the
high 60's to below 50°F.

   If the male bass  leaves the nest for any length
of time  or  for  any  cause, death of the embryos
or  fry  by predation  usually  occurs  (11).  Nest
abandonment may  come about through a temperature
drop, which causes the male to desert the nest. Also,
when male  bass  are  caught,  leaving a nest full
of fry or eggs, the nest may be lost either through
predation on the fry by  small  sunfish, or through
lack of proper aeration.

   The idea of a closed fishing season during the time
of spawning to protect male bass on nests has proved
to be largely theoretical (3). The production of new
year-class of  bass was less dependent upon whether
or not  male  bass  could  be legally  caught, than on
many other factors.   In  the first place,  bass are
not  stupid,  and  many of them refuse  to  become
hooked.  Then too, bass that are hooked or at least
pricked by hooks, plugs, or bait, and  escape, go
back to their  nest with knowledge that will prevent
them from becoming hooked a second time.  Murphy
(19)  studied the production of largemouth bass fry
in parts of a lake  in California that  were closed
to fishing and in other parts that  were open to fishing
during the spawning  season; he  concluded that there
were no  more small bass in areas that were closed
to fishing than in areas that were  open.  Later, during
a year when the entire lake was open to fishing, there
were more small bass available than were present
in any  situation  in the year of the original study.
There  is overwhelming evidence,  however,  that the
vulnerability of the eggs, fry, and the young during the
early months  of  life  control the size of the bass
populations.

   Kramer and   Smith (14) stated that  year-class
strength  of largemouth bass was set during the first
few days or months of life and was affected by a number
of variable factors, including the size and fecundity
of spawning  stock, weather, physical-chemical  and
biological conditions of the habitat, food, and preda-
tion.  Bennett (3) could demonstrate no relationship
between number of  spawners and the size of a year-
class produced.
        SENSITIVITY TO CHANGE IN pH AND
                DISSOLVED OXYGEN

   Bass are not very sensitive to moderate changes
in their environment as long as these changes do not
exceed  a  certain  definite  range.    For  example,
largemouth bass fingerlings, 3.5  to 6.0 inches long,
tolerated  rapid  changes  in pH from  8.1 to 6, from
7.25 to  9.3, from 9.2 to 6.1, and from 6.1 to 9.5 (24).
In other experiments, Wiebe determined that bass
were not affected by excessively high dissolved oxygen.

   Moss and Scott (18) made a series of experiments
in which they tested the minimum oxygen requirements
of small largemouths. Using a shock treatment tech-
nique in which the dissolved oxygen was rapidly reduced
from  near saturation,  they found that at 25°C   the
minimum requirement was 0.92 ppm.  At 30° C
the minimum was 1.19 ppm, and at 3 5 °C the minimum
requirement was 1.40 ppm.  When these bass were
acclimated gradually  to  low oxygen they were able
to get along on  somewhat  smaller amounts.  For
example, at 25°C  the requirement range of acclimated
bass was 0.78 to 0.84 ppm;  at30°C from 0.79 to 0.87
ppm; and at  35°C,  1.20  to  1.32 ppm.  It is probable
that spotted  bass and smallmouth  bass would  die
at higher minimum oxygen levels than the largemouth
bass.

            LETHAL TEMPERATURES

   Brett (6) lists upper and lower lethal temperatures
for largemouth bass that previously have been ac-
climated to temperatures of 20° 25,°and 30° C. These
are shown in Table  1.

     Table 1. LETHAL TEMPERATURES OF
               LARGEMOUTH BASS

                High temperatures

    Ace. Temp.                Lethal Temp.
   20° C (68° F)
   25° C (77° F)
   30° C (86° F)
—      32.5° C (90.5° F)
—      34.5° C (94.1° F)
—      36.4° C (97.5° F)
               Low Temperatures

    Ace. Temp.                Lethal Temp.
   20° C (68° F)
   30° C (86° F)
        5.5° C (41.9° F)
        11.8°  C (53.2°F)
   Similar tests made on bluegills indicated that they
were more sensitive to high temperatures than large-
mouths but somewhat superior in their ability to with-
stand  low  temperatures.   Similar information for
spotted and smallmouth bass is apparently not avail-
able.

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158
ENVIRONMENTAL REQUIREMENTS OF FISHES AND WILDLIFE
          PREFERRED TEMPERATURES

   According to Fry (9) fish prefer a certain tempera-
ture range which is "the region, in an infinite range
of  temperature,  at which a given  population will
congregate with more or  less precision —atempera-
ture  around which all  individuals  will  ultimately
congregate, regardless of their thermal experience
before being placed in the  gradient."  Ferguson (8)
lists field  observations of the preferred  temperature
for largemouth  bass  as  26.6°  to  27.7°C  (79.9° to
81.9°F),  spotted bass as 23.5° to 24.4°C  (74.3° to
75.9°F),   and smallmouth bass as 20.3° to 21.3° C
(68.5°  to  70.3°F).  The   preferred  temperatures
for largemouth and  spotted bass were based, however,
on field observations in Tennessee and the smallmouth
from northern Wisconsin.   One might  assume that
smallmouths from  northern Wisconsin would demon-
strate a lower preferred temperature than this species
in waters farther south where summer water tempera-
tures normally  greatly  exceeded  21°C   (69.8° F).
Laboratory tests with  smallmouths showed the pre-
ferred temperature was 28°C  (82.4° F),but such tests
with both largemouths and smallmouths showed higher
preferred temperatures  than  those recorded  in field
observations.
THE  EFFECTS  OF  COMPETITION WITH  OTHER
                     SPECIES

   Individual species  of  fish inhabiting  an aquatic
habitat are affected by other species of fish inhabiting
the same water.   These other species may serve as
food for piscivorous species if the former are of such
sizes as to be edible.  If they are too large to serve
as  food, it is probable  that their offspring  serve
such  a  purpose until  they, in turn, grow too large.
As  suggested by  Kawamoto (12),  Rose  (20), Swingle
(21),  and  Yashouv (25),  fishes  may  influence  one
another by  the secretion or excretion of waste products
or hormonal substances that may inhibit growth or re-
production  of individuals  of the same species or of
other species  inhabiting  the  same water.  This is
competition for space, a phenomenon that has  been
recognized, but until recently very little has been done
about it. Yashouv (25) demonstrated that fishes were
able to  excrete a substance, which, when added to an
aquarium  containing  other  fishes,  prevented  these
other fishes from making normal growth. When this
substance was  given to rates in their drinking water
the result was similar to that of vitamin Bj deficiency,
and  eventually resulted  in the  death  of the rats.

   Swingle   (21) found  that goldfish held in relatively
large numbers in small ponds would not spawn regard-
less of the  season. As soon as a few of these fish were
removed from the concentrated population and placed
in a  pond  containing fresh water, they ripened and
usually  spawned within 48 hours. Carp, buffalo, and
some other species  are  assumed  to show similar
repression  as  a  result of substances  secreted or
excreted into the water. So far, there is no evidence
that any of the basses or centrarchids are inhibited
in this manner. Certainly overpopulations of stunted
bass, and/or sunfish,  including bluegills, green sun-
fish,  and  others are relatively common. There is
                                no evidence that their reproduction is inhibited, except
                                through predation on eggs and newly hatched fish that
                                normally takes place in  concentrations of this kind.

                                  This inter-predation of bass on sunfish and sunfish
                                on bass spawn is a  very potent factor in the ecology
                                of all of the bass species.  Over a period of years
                                evidence  has accumulated that the number of large-
                                mouth bass, smallmouth bass, and probably spotted
                                bass  as  well, is often controlled  by  the species
                                of fish that  inhabit the same water  with them (2,4).
                                Actually, when a new body of water is stocked  so that
                                it may  develop a dominant brood of largemouth or
                                smallmouth bass,  these fish temporarily control other
                                species  stocked with them; i.e.,  the young spawned
                                by the bluegills in a bass-bluegill population may be
                                controlled by  the bass  for  the  first year  or two,
                                provided the number of bass stocked originally is
                                sufficient.   Control  is  not complete, however, and
                                these  sunfish  species manage to produce additional
                                young, with sufficient survival to allow the gradual
                                and  slow build-up of a  population of sunfish. Once
                                this population of  sunfish approaches a density of 4 to 5
                                thousand individual fish  per acre, of  sizes between
                                4.5  and  5.5  inches, they  offer  such  severe  food
                                competition(in most aquatic habitats) to one another that
                                they are  constantly ravenous and  attack any  source
                                of food  available.   Bass guarding nests of eggs or
                                newly  hatched fry are surrounded by milling schools
                                of hungry sunfish  ready to make inroads on these eggs
                                and  fry if the opportunity arises.  Such schools of
                                predatory sunfish eventually stimulate the  guarding
                                male bass to  chase  and  strike a fish that comes too
                                near the nest.   While  this guarding  male bass is
                                gone  momentarily,  sunfish  nearest  the  nest dive
                                in and eat eggs or  fry as rapidly as possible. When
                                the  male bass returns  these fish scatter, but in the
                                short interim when he was gone they consumed perhaps
                                as many as 100  eggs.   One  can see that when this
                                predation continues over the days to hatching, yolk
                                absorption, and schooling, the usual end result is that
                                the nes'. is a total loss. Thus, inter-specific predation
                                on the developing bass, allows  sunfish to  control
                                the  total survival of these bass.  Of the three species
                                of bass considered  here,  probably the largemouth
                                is most capable of protecting its young.

                                  Populations of fish are  common that consist of
                                stunted bluegills, or crappies, or green sunfish, or
                                a combination of  two or more of these  species, and
                                a few large, well-fed, old bass. These bass are unable
                                to produce a new year-class because of the inroads
                                made  upon their reproductive products at the time of
                                nesting.   A part of the reason that the largemouth
                                bass is less vulnerable to this type  of attack  than is
                                the  smallmouth  is  that the largemouth young  not
                                only are very active, but also they swim in a compact
                                school which  is  more  easily guarded  than  is  the
                                scattered school of the young of the smallmouth bass.
                                One compensatory factor may be the fact that the newly
                                hatched  smallmouth fry are  similar in coloration
                                and  size to toad and  frog tadpoles, which  appear
                                in the spring at about the same time.  These tadpoles
                                are  not considered very desirable as food, and for this
                                reason they are at  least partly immune  from  attack.
                                Field  observations indicate  that smallmouth fry are
                                protected  to a certain extent during the very early

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                              The Environmental Requirements of Centrarchids
                                                 159
  free swimming stages by these similarities to tad-
  poles.  When the smallmouths reach lengths of about
  20  to  25 mm, however, they beet me light in color
  and  take on the markings of the adult fish. At this
  time, they are much more active than when they first
  leave the nest, and become scattered in shallow water.

    One reason why smallmouth bass are unsuccessful in
  typical warm-water ponds is because they apparently
  offer poor   competition to  the normal population
  complex of these warm- water ponds (4). I am referring
  to such fish  as green sunfish, bluegills, bullheads, and
  orange-spotted sunfish, which are  normally found in
  and  often dominate warm-water pond habitats.  If
  breeding smallmouth bass are introduced into a pond
  populated by these  warm-water species,  the former
  may spawn, but the survival of their young may be
  nil or very  low.  In a number of experiments small-
  mouth base  were  found to  do  well and reproduce
  successfully in warm-water  ponds  as long  as  these
  sunfish were present in small numbers,  or as long
  as  the  bass were  stocked with those species with
  only little tendency to overpopulate and stunt.  For
  example, 25 smallmouth spawners were used to stock
  a 14-acre warm-water pond. After the first spawn, the
  pond contained a substantial population of smallmouth
  bass that was maintained through natural reproduction
  for several  years  or until  green  sunfish  expanded
  to a  population of several thousand fish per  acre.
  At  that  time, the population of  smallmouth  bass
  was very much reduced and there was no  evidence
  of their ability to reproduce while living with an  over-
   abundance of green sunfish. When smallmouths were
   exchanged  for largemouths  in  the same lake and
   subjected to essentially the same type of competition,
   the largemouth bass were not so  readily controlled
   as were the  smallmouths.

   DISCUSSION

      The  information presented  here does not define
   the environmental  requirements of bass and other
   centrarchids; it has been presented to show that these
   requirements  are  not  very specific, and that vulner-
   ability of bass is  restricted  largely to early stages
   in the life cycle, from embryos in the nests to advanced
   fingerlings.  Probably this high vulnerability of young
   is common to most animals.

      Factors other than undesirable water characteris-
   tics may decimate bass populations in aquatic situa-
   tions  dominated by man.  This is because the basses
   thrive under situations where natural fish predators
   are abundant and not where overpopulation and stunting
   of companion species is the rule rather than the except-
   tion.  Where man dominates  an aquatic environment,
   fish predators are scarce or nearly absent.  Bass
   are often scarce,  not because the water is polluted
   (as it may well be) but because the biological aspects
   of the aquatic habitat are less than optimum for them.

      Thus, the absence or scarcity of  bass in a body
   of water is not an indication that the habitat is chemi-
   cally  or  physically unsuitable  for their survival.
                                               REFERENCES
1. Bartlett,  S.  P.  1908.  Value  of carp  as furnishing
  food for  black  bass.   Am.  Fish  . Soc. Trans. 37
  (1908), 85 -89.

2. Bennett, G. W. 1951. Experimental largemouth bass
  management in Illinois.  Am.  Fish. Soc. Trans.  80
  (1950), 231-239.
3.                 1954.   Largemouth bass  in  Ridge
  Lake,  Coles County, Illinois.   111.  Nat. Hist.  Surv.
  Bull. 26 (2), 217-276.

4. Bennett, G.  W.  and Wm. F.  Childers. 1957. The
  smallmouth bass,  Micropterus dolomieui, in warm-
  water ponds.  Jour. Wildlife Mgmt. 21 (4), 414-424.

5. Breder,  C.M., Jr.  1936.    The reproductive habits
  of the North American sunfishes (Family  Centrar-
  chidae).  Zoologica 21(1), 1-48.

6. Brett,  J. R., 1956.  Some  principles  in    the
  thermal  requirements  of fishes.   Quart. Rev.  of
  Biol. 31 (2), 75-87.
7. Carlander, K. D. 1953. Handbook of freshwater fishery
  biology with first supplement, 429 pp. Wm. C. Brown,
  Inc., Dubuque, la.
8. Ferguson,  R. G. 1958.   The preferred temperature
  of fish and their midsummer distribution in temperate
  lakes and  streams.  J. Fish.  Res. Bd. Can. 15  (4),
  607-624.
 9. Fry, F. E. J. 1947. Effects of environment on annual
   activity.  Ont. Fish. Res. Lab. 68, 1-62.

10. Rowland, J. W.  1932.  Experiments in the propagation
   of spotted black bass. Am. Fish. Soc. Trans. 62  (1932),
   185-188.

11. Hubbs,  Carl  L.  and  Reeve  M.  Bailey.  1938.  The
   smallmouth bass.  Cranbrook Inst. Sci. Bull. 10,1-89.

12. Kawamoto, N. Y. 1961.  The  influence of excretory
   substances of  fishes on their own growth.  Prog.
   Fish-Cult. 23 (2), 70-75.

13. Kelley,  John W.  1962.  Sexual maturity and fecundity
   of the largemouth bass,  Micropterus salmoides (Lac.)
   in  Maine.  Am.  Fish. Soc.  Trans.  91  (1), 23-28.

14. Kramer, R. H.  and L. L. Smith, Jr. 1962.  Formation
   of year classes in largemouth bass. Am. Fish. Soc.
   Trans. 91 (1), 29-41.

15. Lamkin,  J. B.  1900.   The  spawning  habits of the
   largemouth black bass  in the South (Ga.). Am. Fish.
   Soc. Trans. 29, 129-153.

16. Lydell, D. 1911.   Increasing and insuring the output
   and  natural food  supply of  smallmouth  black bass
   fry, and notes on combination of breeding and rearing
   ponds.   Am. Fish. Soc. Trans. 40 (1910), 133-143.

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   160
ENVIRONMENTAL REQUIREMENTS OF FISHES AND WILDLIFE
IV.Meehan, W. E. 1911. Observations on the small-mouth
   black bass in Pennsylvania during the spawning season
   of 1910.   Am. Fish. Soc.  Trans. 40 (1910), 129-132.


18. Moss,  D.  D. and D. C. Scott. 1961. Dissolved oxygen
   requirements  of three species  of fish.   Am. Fish.
   Soc. Trans. 90 (4), 377-393.

19. Murphy, G. I. 1950. The closed season in warm-water
   fish management.  N.  A.  Wildlife Conf. Trans.  15,
   235-251.
20.Rose,  S.  M.  1959.   Failure  of  survival  of slowly
   growing members of a population.  Science 129 (3355),
   1026, April.
                              21. Swingle, H. S. 1956. A repressive factor controlling
                                 reproduction  in  fishes.    Eighth  Pac.  Sci.  Cong.
                                 Proceed. HI A (1953), 867-871.
                              22. Tester, Albert L. 1930.  Spawning habits of the small-
                                 mouthed black bass in Ontario waters.  Am. Fish.
                                 Soc. Trans. 60, 53-61.
                              23. Troutman, Milton B. 1932.  The  practical value of
                                 scientific data in a stocking policy for Ohio. Am. Fish.
                                 Soc. Trans. 62, 258-260.
                              24. Wiebe, A. H. 1931.  Notes on the exposure of several
                                 species of fish to  sudden changes in hydrogen-ion con-
                                 centration of  the  water and to an atmosphere of pure
                                 oxygen.  Am.  Fish. Soc. Trans. 61, 216-224.

                              25. Yashouv, A. 1958.  The excreta of carp as a growth
                                 limiting factor. Bamidgeh   10  (4),  90-95.
                                   WATER QUALITY CRITERIA FOR FISH LIFE

                                                 Marcel Huet *
                    INTRODUCTION

      Surface waters  are not  all identical.
   classifications can be established:
                   Different
      1.  Those waters that provide drinking water for
   the country.
      2.  Waters used  for agricultural purposes and for
   fish culture.
      3.  Waters whose main use  is to fulfill industrial
   needs.
      4.  Waters used  for recreation and water sports.

   It is not easy to define the qualities of water bene-
   ficial  to  fish,  and in any case, it cannot be achieved
   by merely listing numerous chemical-physical values.

      Undoubtedly  it  is  more difficult  to define the
   qualities of water beneficial to fish than the qualities
   essential  for  drinking,  industrial, or  agricultural
   waters.  Indeed,  this difficulty has been stressed by
   the  "Aquatic  Life Advisory Committee Commission"
   (1955).  This  Committee points out that water cannot
   be  considered pure from a piscicultural  point of
   view if, after pollution, it does not produce the quantity
   of fish it  should.  Neither will it be considered pure
   if, after several changes and especially after a constant
   rise in temperature, it produces fish of less economic
   or sport value.   Futhermore,  water is not regarded
   as pure if fishing is affected or if the quality of the
   fish flesh is altered while the quantitative production
   is not affected (Huet, 1949).
   In the first part of this paper we shall consider in
general the main qualities of water necessary for fish;
in  the  second part, we  shall enlarge on certain
essential chemical-physical characteristics.

I.  PRINCIPAL QUALITIES OF  WATER FOR  FISH.

   A.  Essential needs of fish.

   In order that a given population ol fish can exist,
it  is  necessary  that the fish be  able to live and
develop  normally.   This means that the ecological
conditions must be satisfactory.

1. The respiratory needs of fish.
   The needs are very different from one species to
another.  Certain species such as salmonids, require
high dissolved oxygen (DO)  concentration, while other
kinds, such as many fish from tropical regions, only
require  lower concentrations.  If, for western tem-
erate  Europe, one  takes  the required DO concen-
tration of the tench as standard, that of the carp is
two and a half times greater and those of the rainbow
trout six times greater.

2.  Food requirements of fish.

   All  fish do not  have  the  same  feeding habits.
It  is possible to  differentiate immediately  between
the feeding habits of young and adult fish.  In their
early  stage,  all fish feed on microorganisms;  later,
their feeding  habits differ.  The  main  divisions are
as follows:
    Director of the Research Station of Waters and Forests, Geoenendael, Belgium. Professor Extraordinary at the University of Louvain.

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                                    Water Quality Criteria for Fish Life
                                               161
   (1)  Fish eating  aquatic  plants  (algae  or higher
plants).
   (2)  Zooplankton feeders among which the following
distinctions must be  made:   (a)  Those  feeding on
bottom fauna.   (b) Those  feeding on fauna  living
among the submerged vegetation,  (c) Those feeding
on plankton.

   (3)  Mainly  or exclusively piscivorous fishes.

   All  types of water  do not have  the  same nutrient
content.  Waters range from those with high nutrient
levels  to  ones  practically sterile.   The  relative
nutrient  level of a water  is  difficult to measure.
One  method is to determine the "biogenic capacity"
(Huet,  1949) of the water.

   Whatever the  feeding habits of  fish in a specified
situation, their food corresponds to one or several
phases of  the biochemical cycle  that exists  in the
environment.  This cycle originates from the nutrients
in solution in the water.

3. Reproductive requirements.

   The most  important  reproductive  requirements
are temperature and a suitable substratum. Details
on the importance  of temperature  on fish reproduc-
tion  are  given later.   A  suitable  temperature is
necessary for warm water species as well as for cold
water forms.

   The type  of substratum is  extremely  important.
Many fish  lay eggs that stick to water plants, and the
presence  of  these plants is   essential for  the re-
production of  these  species.  In artificial lakes sub-
ject  to considerable fluctuations in water level and
situated at low or  average altitudes, the water heats
sufficiently in the spring to allow  the  cyprinids and
accompanying predators  to reproduce. These fluc-
tuations prevent the  growth  of  aquatic vegetation and
make reproduction of  these species virtually impos-
sible.   In  modern  canals and in  rectified  streams
with stone or  concrete embankments,  absence of
vegetation also occurs.

   The nature of the stream bottom  also plays an
important  part.    Trout kept in  ponds  or even in
fresh  water  streams  with  a  sandy bottom  do not
reproduce.  They require fast flowing streams with
stony or gravelly bottoms; in these conditions, they can
lay  their  eggs  and  the stream   flow  provides a
constant supply of oxygen-rich  water.


   Spawning sites are essential for  fish reproduction;
equally important is the free access to these spawning
places.  Access  can be inhibited or made impossible
by dams and  pollution. The disappearance of salmon
from many streams is  a well-known example.  It
should be added  that damming often warms or cools
the water.   This in  turn can cause a modification
in the  composition of the fish population downstream
from the dam.  It  can also cause an overcrowding
of the water  upstream by those species  which are
regarded as undesirable  and which are increasing in
the impoundment.
4. Conditions of habitat.

   Certain species of fish live in  free water, either
in  the  median  zone  of streams or  in  the pelagic
region of lakes  and ponds as for example, the Core-
gones  that  do  not have any  other  special  habitat
needs.   Other  types  of fish living  in the marginal
or littoral zones of streams  need  aquatic vegetation
and the protection of the roots and  shadowy recesses
of the riverside trees.   Trout, for example, need
sheltered spots  and hiding places. If this protection
is missing as a result of damming or stream improve-
ments, the fish leave the unsuitable habitat.


   In  order  for a  species of  fish to  remain in a
particular  spot,  it is  essential that all the needs
mentioned  above be  satisfied.  Cases exist where
the food  requirements are  satisfied,  but the DO
requirements are not met.

B. Classification of continental waters.

   All continental waters, therefore, should satisfy
the fish's relative needs for dissolved oxygen, food,
and special conditions for reproduction and habitat.
But these needs  themselves are very different depend-
ing on the kind of water one is considering.  By consid-
ering  only  the broad lines  of a generalized  fish
classification, natural  waters  and artificial waters
can be distinguished; the first group can be sub-
divided into streams and standing water.

   Beforehand or concurrently, another distinction
should be established concerning climatic zones and
the difference between continental waters of temperate
zones and those of tropical regions.  Here, only the
waters of temperate regions are reviewed.

   Streams form a network of communication through-
out a  continent, linking the  mountaintops with the
ocean; they are fed by the melt waters  of glaciers,
by  surface runoff,  and from  springs.   Streams
exhibit  many aspects and are inhabited  by many
different species of fish, according to the  fish zone
that exists.

    A  stream flowing  down  from the mountain top
to the sea includes a series  of zones, each of which
has a characteristic  species  of fish that can best
thrive there.    From headwaters  to mouth, one ob-
serves  successively, the trout zone, grayling zone,
barbel zone,  and bream zone.  At the mouth of the
rivers the sparling zone also  occurs, influenced by
salt water through the action of tides. This classifi-
cation is essentially  the result of a joint action of
temperature  and  water velocity.    The  trout zone
and  grayling  zone form the  salmonid  region; the
upper type of barbel zone forms the mixed streams
(fish population with a predominance of running water
cyprinids and of salmonids), and  the lower  type of
the barbel zone and the bream zone form the cyprinid
regions.   Details on the fish populations of these
zones, and the method of identifying them by examin-
ing  their length profile and their slope have been
given  in  one  of our  articles to  which  we refer
(Huet, 1954).

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162
ENVIRONMENTAL REQUIREMENTS OF FISHES AND WILDLIFE
   Among  the natural  standing waters are  lakes,
ponds, swamps, and  marshes.   This  classification
is based    on the  size  and depth of these waters.
Numerous  bases have been suggested for the classi-
fication of lakes.    From  the  piscicultural point of
view, for  temperate lakes one can  adopt a similar
classification to  that adopted for  streams.  Thus,
one  can distinguish between salmonid lakes,  mixed
lakes, and cyprinid lakes.   Similarly, this classifi-
cation is also  based on the temperature of the water
and  the  amount  of oxygen in the  water.  Fish pop-
ulations of various  categories of  lakes are similar
to those in the corresponding categories of streams.
Important differences occur, however, because of the
existence in  the lakes of a pelagic region, which con-
tains a particular population.

   Artificial  waters include ponds  and lakes.  Ar-
tificial lakes can be classified on the same basis as
natural standing water.   The least  satisfactory for
the  fish are those subject to severe fluctuations in
water level.   The reasons for this have already been
pointed out.

   Artificial  ponds are devoted to fish-rearing (fish-
culture) or to  sport fishing. Basically, one differen-
tiates between cyprinid ponds and  salmonid ponds
which need,  respectively,  warm water or  cold water
in the summer.   The  summer temperature of 20°C
marks the separation of these two kinds of fish culture.

   The  cyprinid-culture is concerned with the breed-
ing  of  carp, tench, other cyprinids and their cor-
responding predators, pike, and black bass.   These
species are  reared in shallow ponds, at low altitudes
with only a weak current or none at all. In salmonid
culture,  many kinds  of fish are reared,  especially
the  common  trout and rainbow trout.  They  are
reared  in  waters  that remain cool in  summer and
which are, consequently, found in mountainous places
or, if on plains, next to large springs.

II. ESSENTIAL CHEMICAL-P H Y SIC A L CHARAC-
   TERISTICS OF FISH WATERS

   In this second part a few details on points arising
from certain essential chemical-physical character-
istics of fish waters are given. Although it is diffi-
cult to make a firm choice of these properties, one
can  split  them into two groups:   those essential to
the  life of the fish and to the organisms that affect
this  life, and those which, although necessary, affect
mostly the  intensity of production.

   Among the first group the following must be listed:
temperature, amount of dissolved oxygen, pH, suspend-
ed matter, dissolved toxic materials, and properties
that  give an  unpleasant taste to the flesh of the fish.
In the second group are nutrients dissolved in the water
or  contained  in  the  upper layers  of the  bottom
of the ponds; in optimum  proportion, these enhance
fish  production, especially  primary production.  De-
ficiencies of  nutrients  reduce the production.  These
nutrients  are  salts of calcium, phosphorus, potas-
sium, nitrogen, iron, magnesium, and other elements
such as copper, cobalt, and zinc.   The  abundance
of these  mineral   elements determines  the water
                                  productivity.  A  study of this  aspect of the problem
                                  is beyond the scope of this present treatise. Several
                                  writers, notably Schaperclaus (1961), have contributed
                                  to our knowledge on this subject and have  enlarged
                                  upon the role of nutrients in fish production.

                                     Pinpointing criteria for fish is particularly complex
                                  and difficult and cannot be done without a wide know-
                                  ledge of the needs of fish, with regard to the water
                                  milieu.   That is the reason why these needs were
                                  discussed in the first part of  this paper.  From the
                                  points which  follow, it can be seen that in general
                                  one  can  make  only  relatively  precise,  clear-cut
                                  criteria on temperature, dissolved oxygen, and pH.

                                     Care must  be taken to  avoid confusing the re-
                                  sistance limits  of  these  factors  with  the  optimum
                                  values  admissible  for  the same factor, that will
                                  safeguard the life and normal development of the fish.

                                     One discovers numerous  references  about  the
                                  effects of  substances or factors that  are lethal to
                                  fish after a  fairly short time.   Such  facts are in-
                                  teresting  for establishing those  conditions that are
                                  lethal  to fish;  but, above all, what should be defined
                                  are  those conditions that are indispensable for the
                                  life of the fish and its normal activities.

                                  A. The temperature.

                                      The water temperature is a critical factor in the
                                  life  of fish  and other water organisms and conse-
                                  quently in fish production.  It affects to a considerable
                                  degree respiration, growth, and reproduction of fish.

                                     Each species  of fish has a thermal tolerance zone
                                  in which it behaves in a normal manner; also, there
                                  is a zone of higher temperature  and one of a lower
                                  temperature in which the  species can survive for a
                                  certain  length  of  time.    A  gradual  and regular
                                  acclimatization allows certain species of fish to sur-
                                  vive in temperatures that would  be  fatal if they oc-
                                  curred suddenly. Fish adapt themselves quickly to a
                                  rise in temperature, but less  easily  to a drop in
                                  temperature.
                                     The Aquatic Life Advisory Committee of the Ohio
                                  River  Valley  Water Sanitation Commission  (1956)
                                  points out quite  rightly that a rise in temperature
                                  of 5°C  can  completely transform  a water milieu.
                                  The Rivers  Pollution Prevention Sub-Committee of
                                  England (1949) points out on the other hand that during
                                  the summer  period, a rise in temperature of 1°C
                                  can have adverse consequences.

                                  1. Water Temperature and Fish Respiration

                                     Water  temperature determines, to a large degree,
                                  the amount of dissolved oxygen in the water, and this
                                  is essential for  the breathing of  fish.  The needs
                                  of fish differ  widely according  to species.  Water
                                  temperature ought  not  exceed: 20°C  in  salmonid
                                  waters; 22°C  in mixed waters; and 25°C  in cyprinid
                                  waters.
                                     An increase of 1°C  or even 1.5°C  can temporally
                                  be  tolerated for  salmonid and mixed waters.    For
                                  cyprinid waters,  this tolerance  can be extended to
                                  2° C or even 3°C.

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                                     Water Quality Criteria for Fish Life
                                              163
   As  a  whole, fish of temperate regions are able to
tolerate  temperatures ranging between 0° and 30° C;
but  the  resistance  of  the  various  types of fish
to the highest temperatures in this thermal  zone
differs from  one species  to  another.  The above-
mentioned  cold water fish  (salmonids, for example),
do  not tolerate  high  temperatures while the warm
water  fish (cyprinids in general and particularly
carp) tolerate high temperatures perfectly well and,
to a certain degree, even require them. In temperate
regions,  fish tolerate temperatures of less than 4° C.
This does  not apply in tropical regions; for example,
most  Tilapia   sp.  die when  the temperature drops
below  13 °  C.  In  general,  all  abrupt variation in
temperature can be harmful  to fish, even  if it is
short  lived.  Nevertheless,  the dangers of sudden
variations  have been exaggerated in the past.

   Predators and cyprinids are more sensitive than
salmonids.   In the case   of a low concentration of
oxygen,  the sensitivity is increased.  Whatever the
species,  it is  prudent to  avoid sudden and abrupt
variations  of temperature if the temperature variation
of  the  water  falls  below  6°C.   Several   writers
recommend avoidance of sudden variations in temper-
ature exceeding 5 ° C.   There are different opinions
about the tolerance of fish to prolonged or temporary
rises of  temperature. For  example, Tarzwell (1957)
mentions that  brown  trout and rainbow trout have
been capable  of  withstanding temperatures as  high
as  28.3°C.  Black  (1953),    however, states   that
24 °C.   is  a  lethal temperature  for  rainbow trout
fingerlings. This limit seems relatively low. Denzer
(1952) fixes the extreme of this danger zone at 24.5° C
for rainbow trout fingerlings, and the ideal tempera-
ture for  this same type at  between 9°C  and 18.5 C
Fry  (1951) states that brook trout fry have  tolerated
temperatures  of  23.5° C for 12 to 14 hours.  The
lethal temperature forSalvelinus namaycushis 23.5° C
and  the  best  temperature  for  this type is between
15°C  and  17°C  (Gibson and Fry, 1954). Research
on  several salmonids, undertaken by the  Southern
Research Station, Maple, Canada, shows that the lethal
temperatures of various salmons, Critivomer namay-
cush and Salmo fario is between 23.5°  C and 25.3° C,
depending on the  types and  experimental conditions.

   According to  Liebmann  (1960), pike can  tolerate
temperatures  up  to  29°C.;   most of the cyprinids
can  survive up to 29°C  to  31 °C  and even higher;
carp can go as high as 36°C  to 37°C  and carassins
can even resist temperatures up to 39°C.

   The  preceding values are a little  higher  than
those  quoted  by  the Rivers Pollution  Prevention
Sub-Committee of England (1949), whose lethal limits
are  25°C   for  common  trout; 30°C  for  pike; and
35 °C  for  the goldfish.  This Committee  suggests
that  these  same  types of fish  can live during pro-
longed periods at temperatures to 22°C  for trout;
27°C  for  pike; and 30° C  for carassins, as long as
the transition  to  the higher temperatures is carried
out  slowly  and progressively.   Abrupt  changes  of
temperature are  regarded  as harmful or deadly  to
the  fish.   In the second  Progress  Report of the
Aquatic Life Advisory Committee of the  Ohio River
Valley Water Sanitation Commission (1956) can be found
the  lethal  temperatures for  many  kinds  of  fresh
water fish of North America.

2. Water  temperature and the growth of fish.

   Water  temperature influences  the growth of fish
considerably.  Growth of carp is  very good between
28°C  and 20°C   average between 20°C  and 13° C,
poor  between    13° C and    5°C, and non-existent
below  5°C.      The optimum temperature  varies
according to type.  In general, the best temperatures
for  growth  of  salmonids lie between  15°C,    and
18° C. It is desirable that in water  where one is rais-
ing one  or  more  species of fish there should be a
temperature close to the optimum  of the fish in
question for as long as possible.

3. Water temperature and fish reproduction.

   Temperature  is a factor in fish reproduction in
a  special and  important manner.  Fish only spawn
when the  water  reaches a suitable  temperature.
In western  Europe, some fish spawn in winter at low
temperatures; e.g., salmonids. Pike spawn in the
spring with the  first warming of  the water when the
temperature reaches 10°C;   the common perch
spawn a  little  later when  the water  temperature
reaches  or  exceeds  12°C;    most of the cyprinids
spawn at  the end of  spring in water temperatures of
15°C,  and above. The chevinne need 12°C to  15°C,
the roach 12° C  to 16°  C, and bream need  17° C.
For  carp the  water temperature  must be  18° C,
and higher for tench.

   It is essential  that the required temperature should
be  reached at the  right  time; if not, the fish do not
breed.  Cyprinids,  for example, do not reproduce if
the water is not  sufficiently  warm in the spring; on
the other hand,  salmonids   do not reproduce if the
water does  not get cold  enough in the autumn.  This
factor limits the reproduction of trout in tropical
regions.  According to the Rivers Pollution Prevention
Sub-Committee  of  England  (1949), the  eggs of the
common  trout cannot withstand a temperature higher
than 14.4° C.
   Any abnormal variations in temperature during the
period of reproduction, causing  either  a sudden
raising  or  lowering  of  the water  temperature,  are
especially injurious.  An early heating of the water
in spring can initiate  reproduction of the warm water
fish of temperate regions but the eggs or the fry are
destroyed by a subsequent cold spell.

B. Di solved oxygen.

   The importance  of this element, essential for the
respiration  of fish, is very  marked.   Fish are  very
sensitive  to any decrease in the  volume of oxygen
and  die  of  asphyxia  very quickly.  It is important,
therefore, that fish never have to withstand the lethal
dose even for a short  period.

   The amount of dissolved oxygen in the water de-
pends mainly on the water temperature, the amount of
organic matter, and underwater vegetation. In natural
waters, the  most  important  factor  influencing  the
amount  of dissolved  oxygen  is temperature.  Tern-

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164
ENVIRONMENTAL REQUIREMENTS OF FISHES AND WILDLIFE
perature is important because the more the tempera-
ture rises, the less dissolved oxygen there is and the
oxygen consumption especially through the oxidation
of organic matter is increased.

   The amount of dissolved oxygen also  depends on
the quantity of organic substances found in the water.
If this quantity is high, the  oxidation of these sub-
stances  uses up a considerable amount  of  the dis-
solved oxygen in the water, and the concentration
can  decrease below  the necessary minimum.   This
can  happen from natural causes.  It  happens during
the stagnation period in the  hypolimnion of eutrophic
lakes; it also happens  in  winter under  the  ice in
stagnant  water that has a  weak current; it happens
often  in water  polluted by organic matter,  from
domestic sewage,  and  some  types  of  industries.

   The amount of dissolved  oxygen normally  required
by fish  and the minimum  concentration  they can
tolerate differ drastically from  one type to another.
One finds many facts and opinions on this subject
and  the  resultant figures have little similarity.  This
is not surprising  if one   considers  the variety of
types  of fish  studied, the  conditions of the  study,
whether  in  natural water  or in the laboratory, the
methods  of  investigation,  and the interpretation of
the results (Tarzwell, 1957).

   The average minimum  dose permissible for carp
is from  3  to 3.5  milligrams per liter, and for the
trout from 5 to 5.5 milligrams per liter (Schaperclaus,
1954).   Quantities that are  markedly lower can be
tolerated but only for a short time.  They  can drop
to  1.5 or even  1.0  milligrams  per  liter  for trout
and  0.5  milligrams  per liter for carp  and  tench.
There are no  absolute minimum amounts supported
by fish, they depend on many ambient factors mentioned
above, most  notably  the  temperature,  and those
properties  of  the fish itself, such as species, age,
size,  and  activity.   Young fish or  breeding  fish
have greater needs.  Salmonid eggs lyinginthe gravel
need water rich in oxygen.

   In  practice,  normal natural  waters  must sub-
scribe to the following conditions. Within the limits
which  have just been laid  down,  salmonids and
mixed waters should have a dissolved oxygen con-
centration  of  at least  80  percent  of saturation;
locally and temporarily, this amount can be reduced
to not less than 5 milligrams per liter. In cyprinid
waters,  the  amount of  dissolved  oxygen  should nor-
mally be at least equal to 70 percent of saturation:
locally and  temporarily  the amount can  fall to 3
milligrams per liter.

   For water equivalent to European cyprinid waters,
 Tarzwell (1957,  1958) recommends that the oxygen
concentration  not go below  5 milligrams  per liter
for  more  than  8 hours  in 24,  and never below 3
milligrams per liter  unless the population is composed
only of coarse fish and not  accompanied by predators
having greater oxygen demands.  If  there  are  only
 coarse fish, the  amount  can go  as  low as 2 milli-
grams per  liter.   For  salmonid  waters  Tarzwell
recommends a minimum of  6 milligrams per  liter.
Others  (Discussion  by  Perry  of Tarzwell,  1958)
                                  estimate  6 milligrams per liter  as insufficient and
                                  suggest  probably quite  correctly 7 milligrams per
                                  liter as  a minumum amount for salmonid waters.
                                  As mentioned above, minimum values of 5 milligrams
                                  per liter for salmonid waters and  3 milligrams per
                                  liter for  cyprinid waters have been  given by  other
                                  writers (Ellis, etc., 1948).. Graham (1949) has deter-
                                  mined that the  activity of brook trout is reduced be-
                                  low 75 percent saturation whatever the temperature,
                                  and suggests that above 20° C saturation is needed to
                                  allow normal activity.
                                     Fry (1951) estimates  that  an oxygen concentration
                                  of at least 6 milligrams per liter is needed for normal
                                  development  of  salmon eggs and fry.  For  normal
                                  activity  of brook trout,  he estimates 7.6 milligrams
                                  per liter at 15°C, and  saturation if the temperature
                                  is  2° C or more.
                                     One should  fix standards for the  concentration
                                  of  dissolved oxygen in water; it is also necessary,
                                  however,  to fix the  biochemical  oxygen  demand
                                  (BOD)  for a period  such as  48 hours.  The BOD
                                  after  48 hours  should not normally exceed 25 per-
                                  cent of the original amount.

                                  C. pH.

                                     The best water for fish  is that which possesses
                                  a  slight  alkaline reaction — a pH between  7.0 and
                                  8.0.   Fish  can tolerate  acid or alkaline pH levels
                                  but the limits should be between 5.0 and 9.5.

                                     Temporarily lower or higher values canbereaspn-
                                  ably well tolerated for  various periods depending on
                                  the type of fish.   Tarzwell (1957)  points  out that
                                  certain fish have been able  to live for long periods
                                  at  pH of 4.5 to 4.2.  The  extreme limits that fish
                                  cannot withstand are  close  to  4.0 and  10.0.  One
                                  can find details concerning the pH values that have been
                                  tolerated  by various kinds  of fish.   All species of
                                  fish  do  not  resist equally  a low or  high pH. Carp
                                  are  fairly sensitive  to a low  pH; such fish do not
                                  tolerate  a pH  less  than  5.0 for  long.  Trout eggs
                                  die in a pH of 4.8.

                                     The pH of the majority of natural waters lies be-
                                  tween 6.0 and 8.5, but in moor water it can drop to
                                  4.4.   Wherever  possible,  it  is desirable to maintain
                                  the pH between 6.5 and 8.5.  Sudden and appreciable
                                  variations of pH in the water  are undesirable.

                                     It  is  important to point  out that  pH  has an im-
                                  portant  indirect effect because of its influence on the
                                  toxicity  of  certain substances,  such as  HCN, I^S,
                                  and NH3.

                                  D. Suspended matter.

                                     A sufficient but not excessive limpidity is a pro-
                                  perty of  good  water for fish.   The  limpidity must
                                  be sufficient because turbidity acts in an unfavorable
                                  way  on  the productivity of the water.  The shortage
                                  of light  prevents  or interferes with plankton, bio-
                                  logical  covers, and  aquatic plants,  resulting in  a
                                  lower  nutritional  value  of  the milieu.   Tarzwell
                                  (1957) mentions that one finds  seven times  fewer
                                  organisms in a river downstream  from a mine than
                                  upstream.

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                                     Water Quality Criteria for Fish Life
                                               165
   The turbidity of water can be due to natural causes
such as  milky and  cold water  caused by  melting
glaciers  or  heavy  rain,  melting snow, debris,  and
dead leaves.   But turbidity can also be the result of
pollution  caused by quarries, cement-works, gravel-
pits, and  even by numerous industries manufacturing
orgaa'c materials.  Turbidity can be caused by solid
particles  that settle quickly or by colloidal matter that
remains  in  suspension for a  long time.   Erosion
from various causes, especially  deforestation,   can
have serious  and damaging consequences.  This is
an example of what is happening in the United States.

   Water  turbidity  can be harmful to  fish not only
indirectly by  reducing  the nutritive  value of  the
milieu, but also directly if the suspended particles
harm  or  block the gills.  It must be pointed out,
however,  that  fish  easily tolerate high  turbidity
for  long  periods except  when the  turbidity is  ac-
companied by acids,  allkalies, or  substances  that
injure the gills and prevent their functioning normally.


   The resistance of fish to turbidity varies according
to type.   Carp and silurids tolerate a high degree of
turbidity.   This does not apply to predators and is
perhaps  the reason for the inopportune propagation
of the carp  in  certain parts of the  United States
(Huet, 1959).


   In general, turbidity is more  harmful to  the  nu-
tritive richness  of the water  than directly to  the
fish.  Disturbed  water  and the resultant deposits
can  also  interfere with or completely prevent the
reproduction  of  fish by destroying the  eggs  or  the
breeding places.


   High transparency is also an indication of nutritive
deficiency.    The  difference  between  oligotrophic
lakes  and eutrophic lakes  is well  known.   In the
former transparency can reach 25 meters or more,
while  in  the  latter where  water is productive, it
can  fall  to  less  than 0.50 meters as  a result of
considerable plankton development.

   The Aquatic  Life   Advisory  Committee  of  the
O'.iio River  Valley  Water  Sanitation  Commission
(1956) estimates that in order to maintain the most
favorable  conditions  for the  growth  of  the more
important water  plants, it is essential that the water
transparency  should be such that at least 25 percent
of the sun's  total  radiation  reaches the  plants.

E. Dissolved matter.

   Pure water for fish must contain sufficient quanti-
ties   of  nutritive  salts  necessary  for   plant and
animal life  in  the  water.    These salts  exist in
innumerable quantities and new ones are made daily.
Substances  exist in certain natural  waters that are
harmful  to  the fish such as  excess iron, sulphur,
salt  water,  or moor water.  Most of the substances
toxic to fish are put into the water by man.  Several
writers, among them Steinmann  (1928), Ellis (1937),
Doudoroff and Katz (1950 and 1953), Vivier  (1957),
and  Liebmann (1960),  have contributed  to the litera-
ture  on this subject.
   Fish toxicology is  a very complex science.  For
each  substance one  attempts to determine  several
values:

   (1)  The  "minimum  lethal dose"  (Todlich keits-
oder  Letalitatsgrenze), which  is  reached when the
concentration employed still causes the fish's death
during the standard experimental period.

   (2)  The  "dilution limit" (Empfindlichkeitsgrenze),
which  is  reached  when the  concentration employed
does not  cause unfavorable effects on the fish, either
during the standard experimental period, or during the
course of the next 2 days.

   In reality, the study of the toxicologicalphenomena
is much more complex. Wuhrmann and Woker (1948)
distinguish  between a latent phase and a lethal phase,
each of which has its  own important characteristics.

   Several  writers, notably  Doudoroff (1951),  con-
ducted experiments to  discover the "Median Tolerance
Limit  (TLOT)" which  is  the concentration at which
a substance or an effluent kills 50 percent of the fish
during the  period of  the  experiment (48 hours, for
example).    The  permissible  tolerance for waste
waters is obviously  less and  as a rough approxi-
mation can be  fixed  at only 0.1 of  the TLm; this
value  of  0.1  is  clearly  subject to  verification and
modification, however.

   Facts arising from  research on fish toxicology are
difficult  to  establish  and interpret,  unfortunately.
Numerous specific and ecological  factors determine
variations in the results of toxicology tests. Among
the specific factors are the type  of fish (there are
considerable differences in the sensitivity of different
types—trout  are very sensitive, the pike less so,
and  carp and  tench  considerably less); the age of
fish (young fish are often more sensitive than adults);
the physiological state (breeding period); and the
state   of  health.   Important among the ecological
factors are  temperature (a rise in temperature usually
aggravates  the   toxicity);  the  amount  of  dissolved
oxygen (the toxicity  of many substances increases
if  the  amount of dissolved  oxygen in a particular
place  is  reduced); and the chemical composition
of the water.
   Variation in the effects   of toxic substances  is
produced  by differences in  the composition of the
receiving waters.  Therefore, it is of little practical
use to refer  to the literature about the toxicity of
materials in complex water  containing different sub-
stances.     The  results of  many  past experiments
are of little  use because the  composition of the
water  in  which  they  were  conducted  is not known.
Another complication arises  from the fact that dis-
charged substances are mixtures whose reactions are
different  from  their  components.   Synergistic  or
antagonistic actions often result.

   On  the question of  the  toxicity  of complex waste
water, the  best  method of approaching the  problem
is to do the  experimental tests with the whole effluent
and dilute with water from the receiving stream col-
lected at the place where the waste is being discharged
(Tarzwell, 1957).

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 166
ENVIRONMENTAL REQUIREMENTS OF FISHES AND WILDLIFE
    The influence of temperature and  the amount of
 dissolved oxygen on the toxic effects of fish poisons
 has  been particularly  stressed by Wuhrmann  and
 Woker (1955).
    The influence of pH on the  toxicity of several
 substances has  been mentioned above.  For many
 substances (weak inorganic acids and organic acids)
 a decreased  pH increases the  toxicity.  Ammonia
 becomes much more toxic if the pH increases above
 8.0.   The influence  of pH  on  cyanide is particularly
 great.  Doudoroff (1956) discovered that the nickel
 cyanide  complex  was  tolerated a  thousand times
 better by the fish at a pH of 8.0 than at 6.5.
    With a view to coordinating the toxicity tests and
 making  their results comparable,  a standardization
 of tests was proposed by Swiss, French, and Belgian
 experts at a meeting in Zurich, in 1952. The length
 of the experiment is obviously of great importance;
 for practical reasons, one stops often after a period
 of 6 hours.  Doudoroff et al. (1951), Herbert (1952),
 and  Henderson and Tarzwell (1957) have suggested
 methods for conducting toxicology tests.
                                  F. Substances giving a bad taste to the flesh of fish.

                                    Water for  fish production  should be  free  from
                                  substances  capable of giving a bad taste to the flesh
                                  of the fish.   Certain substances, especially phenols,
                                  are  toxic  to fish at a  certain concentration.  At
                                  greater  dilutions,  they no longer threaten the  life of
                                  the  fish,  nor  are  they  harmful  to  the fish food
                                  organism, but they give such an obvious and unpleasant
                                  taste to the flesh  of  the  fish that they are rendered
                                  unpalatable.  Because of this, fishing as a sport and
                                  for   commercial  purposes is  seriously  impaired.
                                     The unpleasant taste of the fish flesh can come from
                                  natural  causes as for example the muddy taste given
                                  by the blue-green algae  of the Oscillatoria species.
                                  In fish culture the taste of the flesh can be influenced
                                  by bad  food.   Often  in  flowing water, the taste of
                                  fish flesh is altered by waters that influence the fish
                                  directly or  through  the  contaminated food they eat.
                                  Petrol,  mineral oils, water from refineries, chloro-
                                  phenols, and phenols are  especially offensive.  Phenol
                                  concentrations of 0.1 milligram per  liter, and even
                                  as  low  as   0.02  to  0.03  milligram per liter are
                                  enough  to  contaminate the flesh of  the fish,  parti-
                                  cularly  if they  are  kept in  boxes.   Several weeks
                                  are needed to rid the flesh of a fish of the  unpleasant
                                  taste it  has  acquired.
                                               REFERENCES
 Aquatic Life Advisory Committee of the Ohio River
 Valley Water Sanitation  Commission.  Aquatic life
 water quality criteria.   First progress report, Sew.
 and Indus.   Wastes,  27 (3), 1955, 321-331.  Second
 progress  report,  Sew. and  Indus.  Wastes,  28 (5),
 1956,  678-690.

 Black  E.  C.   Upper  Lethal Temperature of Some
- British Columbia Freshwater Fishes. - - Journ. Fish.
 Res. Board of Canada, 10 (4), 1953, 196-210.

 California  Institute of  Technology.   Water  quality
 criteria.  State water pollution control Board, Sacra-
 mento Cal.,  Publication N° 3, 1952, 512 p.


 Denzer  H.  W.   Akute  Hypoxie  und Atemfrequenz
 bei Regenbogenforellen-Setzlingen.—Der Fischwirt,
 1952 (7), pp241 bis 244.

 Doudoroff P. and Katz M. Critical review of litera-
 ture on the toxicity  of industrial wastes and  their
 components to fish.—I. Alkalies, acids, and inorganic
 gases.   Sew.  and Indus.   Wastes,  22 (11), 1950,
 1432-1458.   II.    The  metals  as  salts.  Sew. and
 Indus. Wastes, 25 (7), 1953, 802-839.

 Doudoroff P. et al. Bio-assay methods for the evalua-
 tion of acute toxicity of  industrial wastes to fish.
 Sew.  and  Indus.  Wastes, 23 (11), 1951, 1380-1397.

 Downing, K.  M.  and Merkens J. C.  The influence of
 temperature on the survival of several species of
 fish in low tensions of dissolved oxygen.—The Annals
 of Applied Biology, 45 (2), 1957, pp. 261-267.
                                  Ellis  M. M.  Detection and measurement of stream
                                  pollution.—Bulletin of the Bureau of Fisheries, XLVm,
                                  1937,  Bui. N° 22, pp. 365-437.

                                  Ellis  M. M., Westfall B. A.,  Ellis M. D. Determin-
                                  ation  of Water Quality.—Fish and Wildlife  Service,
                                  Research Report 9, Washington, 1948, 122 p.

                                  Fry F.  Some environmental relations of the  speckled
                                  trout  (Salvelinus fontinalis).    Rept.  Proc.  N. E.
                                  Atlantic  Fish.  Con.,  1951.   (cite d'apres Tarzwell
                                  1957).)
                                  Gibson  E.  S. and  Fry  F. E.  J. The performance
                                  of the Lake Trout  Salvelinus  nameycush,  at various
                                  levels of temperature and oxygen pressure.—Cana-
                                  dian Journal of Zoology, 32, 1954, 252-260.

                                  Graham  J.  M.   Some effects of temperature and
                                  oxygen  pressure on the  metabolism and activity of
                                  the speckled trout  Salvelinus  fontinalis.—Can. Jour.
                                  Res. D, 27, 1949, 270-288.   (Cite d'apres Tarzwell
                                  1958).)

                                  Henderson   C.  and Tarzwell  C. M.   Bio-assays
                                  for control of industrial  effluents.  Sew. and Indus.
                                  Wastes, 29 (9), 1957, 1002-1017.

                                  Herbert  D W.  M.   Measurement of the toxicity of
                                  substances to  fish.—Water Pollution Research Lab-
                                  oratory, Watfords, 1952, 8 p.

                                  Huet M. La pollution des eaux. L'analyse biologique
                                  des  eaux polluees.   (Bui. Centre  Beige  Etude et
                                  Documentation  Eaux, n°  5 et  6.)  Trav. Stat. Rech.
                                  Eaux  et ForeHs, Groenendaal, Ser.  D, n°  9,  1949,
                                  31 p.

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                     Toxicity of Some Herbicides, Insecticides, and Industrial Wastes
                                               167
Huet M.  Appreciation de la valeur piscicole des eaux
douces.  Trav. Stat. Rech. Eaux et Forets, Groenen-
dall, Ser. D, n° 10,  1949, 55 p.

Huet  M.    Les  eaux  continentales.—Un Livre  de
1'Eau.   Centre Beige Etude et Docum. Eaux, Liege,
volume II, 1955, 59-71.

Huet,  M.—Compte  rendu de  mission piscicole aux
Etats-Unis et au Canada-Debut  septembre-mi-oct-
obre 1958.  Groenendaal, 74 p., 44 fig.  1959.

Hynes  H. B.  N.   The Biology  of Polluted Waters.
Liverpool, University Press,  1960, 202 p.

Liebmann  H.     Handbuch der   Frischwasser-und
Abwasserbiologie.  Band II, R.  Oldenbourg, Miinchen,
1960, 1149 p.


Mann H.  Ueber Geschmackbeeinflussung bei Fischen.
Der Fischwirt, Jg. 3, 1953, 330—334.


Rivers  Pollution Prevention  Sub-Committee of the
Central Advisory Water Committee.—Prevention of
River  Pollution.—His  Majesty's Stationery  Office,
London, 1949,  76 p.

Schaperclaus W. Fischkrankheiten.  Dritte Auflage.
Akademie-Verlag,  Berlin,  1954,  708 p., 389 fig.
Southern Research Station, Maple, Canada.   Annual
Report of the Laboratory for Experimental Limnology.
—Res Rep. N°23, 1951, 18 p.

Steinmann P.   Toxicologie der  Fische.—In Demoll-
Maier: Handbuch der Binnenfischerei Mittileuropas,
Bd. VI, Lf. 3.  Stuttgart, 1928, pp. 289—392.

Tarzwell  C. M.  Water quality criteria for aquatic
life.  p.  246-272,  in Biological problems in water
pollution.    U.S. Depart,  of Health,  Education,  and
Welfare,  Public  Health  Service,  Cincinnati, 1957,
272 p.

Tarzwell   C. M.    Dissolved  oxygen requirements
for  fishes, pp,  15-24  in  Oxygen relationships in
streams.    U.S.  Depart, of Health,   Education  and
Welfare,  Public  Health  Service,  Cincinnati, 1958,
194 p.  Tech Rept W58-2.

Vivier  P.  Importance des Tests biologiques dans la
protection  des  rivieres  centre la poluttion.  Gen.
Fish. Counc.  for  the Mediterr.,  Proc.  and  Techn.
Rap., Rome, 4,  1957, 207—217.
Wuhrmann K.  und Woker H.  Experimentelle Unter-
suchungen iiber die Ammoniak-und Blausaurevergif-
tung.   Schweiz.    Zeit.   f. Hydrologie, XI, 1948,
210—244.
Wuhrmann K.
la poluttion.
77-85.
La protection  des rivieres contre
Bulletin  du  Cebedeau, 15,  1952/1,
Schaperclaus  W.    Lehrbuch  der  Teichwirtschaft.
Zwetie  Auflage.  Paul  Parey,  Berlin und Hamburg.
1961, 582 p., 290 fig.
Wuhrmann K. and Woker H.  Influence of temperature
and oxygen tension on the toxicity of poisons to fish.—
Verh. int. Ver. Limnol., Stuttgart, XII, 1955,795-801.
                TOXICITY OF SOME HERBICIDES, INSECTICIDES, AND INDUSTRIAL WASTES


                                        P.  Vivier*and M. Nisbef\
   Results of studies conducted in the laboratories
at the  Station of Applied Hydrobiology on the toxicity
of different compounds are presented here.

   Some tests were continued over a period of 1 or 2
months while others were limited to 6 hours as speci-
fied  by the  "protocole de  Zurich" adopted between
Belgium, Switzerland, and France.

BIOASSAYS CONDUCTED WITH HERBICIDES

   1. Simazine (2-chloro-4-6bis-Ethylaminotriazine)
is employed in the  commercial product  "Herboxy"
at a concentration of 50 percent.   Long-term tests
were  conducted in  small aquaria where reaeration
was  obtained  by means of a small pump.  The fish
chosen was the minnow (Phoxinus phoxinus).  Water
of moderate hardness was obtained by dilution of the
normal  water  of the town with distilled water. Its
characteristics were:   pH 7.4; dissolved oxygen, 9.3
ppm; total alkalinity as CaCO3, 115 ppm; and tempera-
ture, 18° C (± 1°).

   All  concentrations  are expressed as the active
ingredient  of  the  product.   Two series of  tests
were  conducted,  one  in plain water  aquaria and
another  in  aquaria  containing  soil in  the  bottom
and plants (Callitriche and Elodea).
* Director, Central Station Applied Hydrobiology, 14 Av de St. Mande, Paris (12°), France.

f Chief of Chemistry, Central Station of Applied Hydrobiology, Paris, France.

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168
ENVIRONMENTAL REQUIREMENTS OF FISHES AND WILDLIFE
   In  the  first series (without plants) the simazine
at a  concentration of 0.5 ppm was lethal  in less
than 3 days for 60 percent of the fish; in the second
series (aquaria with soil  and plants), however, the
concentrations  of 2.5 and 5.0 ppm (normally used for
this  herbicide) were not lethal during  a period of
1  month.   During this time, the plants disappeared
as a result of the action of the herbicide; whereas they
remained  normal and alive in the control aquarium.

   Recently the composition of the Herboxy was slightly
changed in the by-products of the simazine (which was
always 50 percent in the  Herboxy), and new tests
have shown that the toxicity is reduced by the change.
For  example  the concentration of  5.0  ppm  which
was lethal for  90 percent of the fish in less than 40
hours in the first form,  was lethal for only 20 per-
cent  of  the  minnows in  3  days in the new form.

   2.  Atrazine (2-chloro 4-ethylamino 6-isopropyla-
mine  S triazine)  was tested also at a concentration
of 50 percent in commercial herbicides called A 361,
two years ago, and Gesaprime, this year.

   The A 361 was slightly less toxicthanthe Herboxy,
the concentration of 0.5 ppm being lethal in 3 days for
only 20 percent of the minnows.   The 48-hour TLm
was  1.25  ppm.  In the tests  with soil and plants in
the aquaria,  however, we observed that the A 361
was  still  dangerous; at the  concentrations studied
(2.5 and  5.0 ppm) the minnows were killed between
8 and 15 days, whereas there was no mortality during
1 month with the herboxy.

   If we compare A 361 and Gesaprime (each of them
with 50 percent of atrazine) we observe that the change
in the by-products has reduced the toxicity as the TLOT
is now 3.75 ppm and the maximum concentration that
is non-lethal in 48 hours is 2.5 ppm.

   Table 1 shows the results obtained for these pro-
ducts.
                                     3.  Weedex, Weedazol, and Weedazol T. L. These
                                  herbicides  are  formed with 2-4D and aminotriazol.
                                  They were  studied for 1 month in aquaria under the
                                  same  conditions described above: Temperature, 18°
                                  C  (± 1°); pH, 7.4; total alkalinity as CaCOs, 115 ppm;
                                  dissolved oxygen, between 7 and 9 ppm. The concen-
                                  trations tested were those normally used: 40 and 80
                                  ppm for the Weedex, 15 and 30 ppm for the Weedazol,
                                  and 20 and 40 ppm for the Weedazol T. L.

                                     Because the  toxicity  of these products is low, the
                                  first tests were followed by bioassays conducted in
                                  the field.   The same numbers of fish were placed
                                  in  8 small  ponds, each  of the same area:  1,000 fry
                                  of  roach (Gardonus rutilus L.) and 500 fry of tench
                                  (Tinea tinea  L.) in the first test, and 100 roaches
                                  (weighing  100  to  150 grams)  in the second  test.
                                  After  1 month, each pond was emptied and the fish were
                                  counted.
                                     The results  of these assays indicate that these
                                  herbicides  are  non-toxic  for Gardonus  when their
                                  weight is over  100  grams since in the control pond
                                  less than 10 percent of the fishes disappeared during
                                  1  month.   They are toxic, however, to  young fish;
                                  Weedex caused  a  mortality  of 50 percent, and the
                                  two Weedazols  a  mortality of 75  percent of the
                                  fry of the roach and the tench.

                                          TOXICITY OF TWO BACTERICIDES

                                     The two bactericides tested  contained quaternary
                                  ammonium  compounds.
                                     1.    Sovicide  Tetraminol, a  cyclic  quaternary
                                  ammonium  in powder with  96 to  100 percent active
                                  product.
                                     These  tests  were limited  to  6 hours and the
                                  fish were observed for 48 hours after the test.  The
                                  experimental water  was the same as before.   The
                                  highest concentration non-lethal in 6 hours was 4 ppm,
                                  and the  lowest  concentration at which all fish died
                                  was 8 ppm.
                          Table 1.  TOXICITY TO FISH OF PRODUCTS TESTED
Product
Atrazine
in A 361
Atrazine in
Gesaprime
Simazine in
Herboxy 1960
Simazine in
Herboxy 1962
Algibiol
Highest
dilution
non-lethal
in 48 hr
0.5 ppm
2.5 ppm

5 ppm
7.5 ppm
Lowest con-
centration
lethal in
6 hr
10 ppm
30 ppm
7.5 ppm
Insoluble
50 ppm
Lowest con-
centration
lethal in
48 hr
5 ppm
10 ppm
1.25 ppm
Insoluble
25 ppm
TLm 24-hr
5 ppm
3.75 ppm

Insoluble
20 ppm
TLm 48-hr
1.25 ppm

0.5 ppm
Insoluble


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                    Toxicity of Some Herbicides, Insecticides, and Industrial Wastes
                                               169
   2.  Algibiol,  a mixture of quaternary  ammonium
compounds.
   These tests were limited to 48 hours and we deter-
mined "the dose  minima mortelle")(lowest concentra-
tion  at which all fish died) in 6 hours (50 ppm) and
48 hours  (25 ppm).   The 24-hour TLm was 20 ppm
and the highest concentration at which no fish died was
between 5 and 10 ppm.

   The experimental water and the conditions for these
tests were as described above.

TOXICITY OF COPPER SULF ATE WHEN USED AS AN
                    ALGICIDE

   We should like to refer to an experiment conducted
in the field by L. Mazoit,  R. Dreffier, and collabora-
tors.  They desired to stop the development of algae
in rivers whose water is used for potable  water in
Paris, because the algae  rapidly clog filters.  Two
reaches were selected on a  small stream near Sens
(Yonne).   The upper  reach was used for the control,
and the lower one received a solution of copper  sulfate
sufficient  to  bring the CuSO^  concentration in the
stream to 0.20 ppm.

   In 6 days, 75  percent of the carp and tenches were
killed, as  well  as most  of  the minnows present in
the stream (too  many to  be counted); some of them,
however, tolerated 0.30 ppm.  Among the fauna, all
the larvae of Ephemeropterae were killed while those
of Trichopterae  remained well, seemed excited, and
rushed toward the dead fish.

TOXICITY OF DETERGENTS

   The experiments of J. Wurtz-Arlet on  the anionic
and  non-ionic detergents showed their  toxicity  to
the  eggs  and fry of  brown trout and  rainbow trout.
In her  firs'  work  she studied the  influence of two
alkylsulfates, one primary and the other  secondary,
on the  eggs  and fry of the  brown trout of different
ages  (24 hours,  3 weeks, and 6 weeks).  The condi-
tions of the tests were constant: Temperature,  7°
to 8°C;   dissolved  oxygen,  10  ppm; pH 7.3; total
alkalinity  as CaCO3,  205 ppm.  She  reported that:
1. The  sodium  primary  alkylsulfate  is  less toxic
   than the secondary  alkysulfate for  the fry.

2. The eggs with embryos tolerate, without apparent
   damage,  concentrations up  to  10 ppm during  24
   hours.

3. Fry of  6 weeks are more sensitive than the younger
   ones.

4. Fry  of  6 weeks cannot stand more than one-half
   hour in a  solution with a 10-ppm  concentration
   of active  product,  and none of the experimental
   fish can resist 5 ppm for 15 hours.
   In a second paper, J. Wurtz-Arlet reports bioassays
conducted with a sodium alkylarylsulfonate (anionic
detergent)  and  a  non-ionic  compound, octiphenol,
on  the fry of rainbow trout of 10 days and 65 days,
and on young trout 4, 8, and 15 centimeters in length.
The  water used  was  much  softer than in the first
experiment;  total alkalinity as CaCO3 was 39 ppm,
pH  6.9, temperature between  9° and  14°C,   and dis-
solved oxygen  about 75 percent of saturation.  She
determined the highest concentration non-lethal in 1
hour and 6 hours; the lowest concentrations lethal in
1 hour and 6 hours; andthe 24-hour TLm.  She reports
that:
1. The  toxic action is more rapid at concentrations
   between 15 and 50 ppm for the anionic compound
   than for the non-ionic compound.


2. At lower  concentrations (3 to 5 ppm) the toxicity
   is almost the same for the two detergents.

3. The 24-hour TLm is very near the highest concen-
   tration non-lethal in 6 hours.

4. The young trout of 15 centimeters seem more sensi-
   tive  than  the younger ones, especially in  regard
   to the anionic compound.
TOXICITY OF SODIUM CHLORIDE
   Among the long-term bioassays conducted at our
station,  were those of P.  Laurent who  studied the
resistance of many aquatic organisms  to an Nad
concentration of 10,000ppm (lOgramper liter). These
experiments were conducted to deter mine the influence
of the  discharge,  in the  Rhine,  of  waste   waters
from potash  mines in Alsace.  Among the organisms
studied  were the Cyprinidae (roach, rudd, and dace),
which lived the  longest.  At a temperature of 23° C,
50 percent  of  the  fish were killed in 10 days, and
the other  50  percent in 62 days.  When the tempera-
ture  remained  between 7°  and 10° C, however, the
fish lived for a  long time; only 50 percent were killed
in 70 days.

   Asellus was  the  second  most sensitive form;
50 percent died in 7 days and 100 percent in 48 days.
Fifty percent of the Hydropsyche died in 6 days and
total mortality  occurred in 17 days; 50 percent of the
Dressenia   died in  5 days,  and there  was total
mortality in 10  days; and 50 percent of the Sphaerium
died in less than 2 days with total mortality in 6 days.

   P. Laurent found that the same concentration of 10
grams  per  liter was  also  toxic  to aquatic plants.
In 13  days, the plants (Callitriche,  Helosciadium
nodiflorum, O enanthe fluviatilis) turned yellow and died
in salt water, while they lived very well in the  control
aquarium.   Only  Lemna trisulca   lived  in the salt
solution.

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170
ENVIRONMENTAL REQUIREMENTS OF FISHES AND WILDLIFE
                    TAINTING OF FISH BY OUTBOARD MOTOR EXHAUST WASTES AS

                               RELATED TO GAS AND OIL CONSUMPTION

                     Eugene W. Surber, * John N. English, * and Gerald N. McDermott *
   According  to figures  compiled  by the Outboard
Boating  Club  of America, 6,050,000 outboard motors
were in use in American waters during 1960.  (Shea
1961),   There  has been  a tremendous increase in
water sports during the last decade, especially motor
boating  and  water skiing.   In areas  of intensive
motor boat use, it seemed possible that water quality
impairment might include tainting of fish.

   Laboratory tests  (English  et al., 1961)  showed
that bluegills could be tainted by exposure to water
contaminated  by  outboard motor exhaust.  Ninety
percent  of persons  comprising a taste panel  noted
objectionable  flavor  when the fuel  consumption was
8.6  gallons per acre-foot of water.   The level at
which half of the  panel members noted objectionable
taste was estimated  to  be 1.1 gallons  of fuel per
acre-foot.  The gasoline  used in the study was re-
gular grade,  and the lubricating oil, (1/2 pint/gal-
lon  or a  ratio of  1 to   17) was a popular brand of
packaged outboard motor oil.

   These laboratory experiments demonstrated that
water from an  experimental tank in which outboard
motors  consumed  fuel at the rate of 170  gallons
per   acre-foot  of  water  killed half the  test fish,
bluegills and fathead minnows, in 96 hours at a
dilution of about  1  in 5.  Thus the 96-hr TLm for
water subjected to such use was found to be 19 per-
cent.   This  is not  the  safe  concentration, but the
estimated   level at  which 50  percent   of the fish
would die.   A factor of  10 was arbitrarily applied
for  the  estimation  of a  "safe" level, which in this
case would  be 17  gallons of  fuel per  acre-foot.

   The California Department of Public Health (1961)
reported a  study to  determine  the  effect of the
operation  of  an outboard  motor on water quality.
A 10-horsepower motor  was operated in 200 liters
of water for  varying periods of time up  to 3 hours.
Significant  increases in  chemical oxygen demand,
total  solids,  lead, phenols, oil,  and grease  were
noted in the laboratory tests, but at reservoirs where
boating  was  popular  such materials were not ob-
served in the  surface waters.  The discrepancies
between laboratory and field findings were attributed
to the  relatively  small number of boats  on the re-
servoirs studied  and the  large  dilution  in the re-
servoirs.

   The laboratory  studies  by  English et  al.  (1961)
revealed a need for field studies to determine whether
fish are tainted or killed by outboard motor exhaust
wastes under natural conditions.  In 1961 such field
studies were carried out cooperatively by the Chemis-
                                   try and  Physics  Section  and the Aquatic  Biology
                                   Section  of  the Basic  and  Applied Science  Branch,
                                   Division  of Water  Supply  and  Pollution Control of
                                   the Robert A.  Taft  Sanitary Engineering  Center.

                                                EXPERIMENTAL AREAS

                                      Field  experiments  were  carried out  in three
                                   impoundments, Oeder  Lake,  a nearby sky pond (un-
                                   named),  and Eggerding Pond.  The main test area,
                                   Oeder  Lake,  which is near Morrow, Ohio,  is  an
                                   artificial  impoundment,  the  main body  of  which
                                   contains  6.89 acres,  with an average  depth of 11
                                   feet  and a volume of 74.8 acre-feet.   On August
                                   15, 1961,  the lake  was stratified at a depth of 15
                                   to 20 feet.   Below this level in the deeper part of
                                   the lake, the  oxygen content was less than  0.5 ppm
                                   and  at  23  feet the DO was absent.  Fish activity
                                   was  limited,  therefore,  to  those areas  less than
                                   15  feet  deep during  midsummer.   Approximately
                                   40 percent of the  volume of water  was contained
                                   in the upper 4-1/2 feet.

                                      The lake is privately owned by a contractor who
                                   permitted his employees and friends to use the area
                                   for water  skiing, boating, fishing, and  picnicking.
                                   Water skiing was quite heavy through the late spring
                                   and summer.  The owner cooperated in requesting
                                   his boating visitors to record the number of hours
                                   they operated boats, the horsepower of motors used,
                                   the number  of gallons of fuel  mixture  burned,  and
                                   whether the gasoline was white or leaded.

                                      The  control  area  was a  sky pond on the same
                                   grounds  as Oeder Lake, less than a half-mile away,
                                   in the same  general  watershed.  It is  a half-acre
                                   sky pond receiving its water entirely from surface
                                   drainage from the pasture area  above it.  Although
                                   located  below Oeder Lake, it does not receive drain-
                                   age from it.


                                      The  pond  remained  clear  throughout   the  test
                                   period except for plankton growths.  It is completely
                                   surrounded by  fences,  which   prevent  access  by
                                   livestock.   The  control pond has  an average depth
                                   of 6 feet; its volume is 3 acre-feet.  An  early spring
                                   growth  of   Potamogeton crispus,  which was quite
                                   dense about the shore line when  liveboxes were first
                                   introduced, fruited and  disappeared  at  the  onset of
                                   warm weather.  There was no boating on the control
                                   pond.

                                      A second test pond, Eggerding Pond, was  used for
                                   operation of outboard motors by project personnel over
 * U.S. Department of Health, Education, and Welfare, Public Health Service, Robert Au Taft Sanitary Engineering Center, Cincinnati, Ohio.

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                           Tainting of Fish by Outboard Motor Exhaust Wastes
                                              171
a known length of time and with known outboard motor
fuel consumption.  The pond has an area of 0.96 acres,
an average depth of 5.4 feet, and volume of 5.2 acre-
feet.   It  is  located  off Red Bank Road within Cin-
cinnati city limits, on the trucking farm of Eggerding
Brothers, less than five miles from the Taft Sanitary
Engineering  Center.    The pond  is  surrounded  by
pasture,  and  the cattle  have access to it, but a deep,
muddy bottom  confines  them  to the  shallow  edges.

   At the onset  of warm weather, floating masses of
filamentous algae threatened interference with the op-
eration  of outboard motors.   The bulk of the algae
(Cladophora)  floated on the  surface and was removed
by seining prior to placing the liveboxes. In addition,
the surface 2 feet of water was treated with 0.3 ppm
copper sulfate on June  26 and July 21 to discourage
new algal growths.


EXPERIMENTAL CONDITIONS

   Adult bluegills (Lepomis macrochirus),§io 8inches
long, were placed in each of the ponds in floating  live-
boxes 2x2x2 feet,  with trap doors, 10 x 10 inches,
hinged to the wooden top.  The frames of the liveboxes
were of 2- x 2-inch  white pine; marine plywood was
used in the solid  wooden top provided to give cover
and prevent the stampeding of the fish. The remainder
of the box was of 2-  or 4-mesh galvanized hardware
cloth.  Up to 30 adult fish were placed in each  live-
box.
   The  fish were fed ordinary  white bread  every
other day.   While it is not a balanced diet, bread
contains sufficient air to float and sinks at a low rate
compared with pelletized, balanced feeds.  The fish
began to  feed upon  the bread almost immediately.
   The test period extended from June 1 to September
20, 1961, in Oeder Lake and the Control Pond, and
from June 29 to September 29,1961, in Eggerding Pond.
At intervals throughout these periods, personnelfrom
the Chemistry and Physics Section collected water
samples for threshold odor determinations and for the
quantitative  determination of oil, lead, carbon chloro-
form extractables, and chemical oxygen demand.  The
water quality aspects of this sampling will be the sub-
ject of another report.   The water analysis data for
threshold odor,  carbon chloroform extractables, and
chlorine demand showed significant increases through
the season.

   The  amount  of fuel  used on Oeder Lake  and
Eggerding Pond is shown  in Figure 1.   The rate of
fuel  use on the  lake  was not steady  but fuel con-
sumption on a weekly average basis was quite steady
through most of  the season.   The average fuel-use
rate  is  equal to the slope of the lines of cumulative
fuel  consumption.   The  collection  of  data on  fuel
consumption was  begun May 24 in  Oeder Lake and
July  14, 1961, in Eggerding Pond.

   On Eggerding  Pond,  outboard motors were op-
erated by project personnel and accurate fuel con-
sumption  records were  maintained.  Four outboard
motors  were used; a 10-horsepower 1960 model, an
18-horsepower 1960  model, a  10-horsepower 1959
model  and  a 5.4-horsepower  model  built between
1939-1949.  Special propellers were used that allowed
the motors  to reach  optimum operating conditions
under fill load  yet moved the  boat at a very slow
surface  speed; thus wave action and violent maneuver-
ing of the boat in the  small pond were avoided.  Six
popular  brands of regular-grade leaded motor gaso-
line and outboard-motor lubricating oil were used as
fuel.   One-half pint of outboard motor oil was added
to each gallon of gasoline.
                 UJ
                 u.
                 u.
                 o
                 UJ
                     5 -
                                                    TIME, days

                                Figure 1. Rate of fuel consumption per acre-foot of water,

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172
ENVIRONMENTAL REQUIREMENTS OF FISHES AND WILDLIFE
STOCKING THE LIVEBOXES

   On  May 25, 1961, two liveboxes stocked with 30
bluegills each  were  placed  near each other  at the
surface in the control pond where there was no boating.
Three  or four  fish at a time were removed periodi-
cally from  these  liveboxes  for  taste  tests and no
losses occurred until July 20 (after 56 days), when
one fish was found dead.  In strong contrast to this,
severe  losses  occurred in  Oeder  Lake  where two
liveboxes were placed at each of three points on the
lake.   Between May 25 and June 1 when the boxes
•were restocked,  losses were  50 percent or  more.
Although the boxes were heavily anchored at the
surface  to   concrete building  blocks,  losses  from
fungused fish occurred until the  boxes were sunken
far enough below the surface (4 to 7 feet)  to prevent
wave action of  passing boats from injuring the fish.
This  saved  enough  fish  so that the lot stocked in
Oeder Lake on June 1,1961, could be sampled through-
out the remainder of the summer.
   Because early losses of fish in liveboxes had been
heavy, a 500-gallon circular tank was set up on July
11  on the permanent dock on the west side of Oeder
Lake.   It was stocked with 75 adult bluegills on July
12.  Several fish were lost in handling or from injury
in attempting to escape  from an initially unscreened
outlet pipe.  The rest of the fish remained in excellent
condition for the balance of the test period. Surface
water was pumped through the tank at a rate of about
12 to 30 gallons per minute. A carbon filter was in-
serted  in a  bypass line for continuous sampling of
hydrocarbons and  other pollutants in the surface
water.   This appeared  to be an  ideal arrangement
because the  fish  could  not  be damaged  by passing
boats nor could they be disturbed by the over-curious
as the lid on the tank could be locked.

   In Eggerding Pond, the adult bluegills were held in
liveboxes at  the surface as in the control pond, but
the fish were not exposed to excessive wave action of
motor boats as in Oeder Lake, because outboard motors
used in the  experiment were provided with special
low-pitch propellers that permitted about 4200 rpm
and  normal fuel consumption without rapid forward
propulsion of the boat.
   The  original two liveboxes were each stocked with
thirty 6- to  8-inch adult bluegills  on June 29.   They
lived normally  through the first week of August; then
on August 11 all fish suddenly died. The kill affected
both livebox  fish and wild fish in the pond. The out-
board  motors had been  operated  heavily that week,
but later observations indicated  that the kill was
probably due  to an outbreak of Cytophaga columnaris.
This bacterial disease appeared immediately upon the
restocking of the original liveboxes plus one new live-
box on August 16.  On August 18, the pond was treated
•with copper sulfate at 0.5 ppm for an average depth of
5 feet, and the losses ceased.

METHODS OF PREPARING FISH
AND SAMPLING BY PANEL

   Two  methods of cooking the fish were employed,
frying  and baking.  Frying was favored in the early
stages of the  study and was used throughout because it
                                   is the  method most widely employed in ordinary kit-
                                   chen practice; baking was started in late August, and
                                   was  continued throughout the test period in order to
                                   compare the two methods.

                                      After the fish were scaled and head  and entrails
                                   removed,  the fish were rolled in cracker crumbs and
                                   fried in vegetable oil in electric frying pans at 380° F
                                   until browned  on both sides.  Usually three fish from
                                   the same  livebox or  lot were fried at a time. During
                                   transportation fresh aluminum foil was used to wrap
                                   the whole  fish.  Each fish when  cooked was usually
                                   divided into four portions, which were wrapped sepa-
                                   rately  in aluminum foil and delivered warm to twelve
                                   panel members. The portions were identified by letters
                                   and numbers in such  a manner that the panel members
                                   did not know the body of water nor the lot from which
                                   the fish came. Fish from the control pond were always
                                   prepared,  identified in the same manner, and delivered
                                   at the  same time  as the experimental pond portions.
                                   This method is  essentially one described by Winston
                                   (1959) and used by a large chemical company for many
                                   years.  It is also similar to the methods used by Davis
                                   (1960)  except that we did not indicate the control fish
                                   to the  panel.    When we did designate  them on one
                                   occasion, all panel members recorded 0 (noobjection-
                                   able flavor); it was  felt, however, that an occasional
                                   fish  might have a muddy flavor or be tainted by natural
                                   means.

                                      During the period when the fish werebothfrled and
                                   baked, the cleaned fish were cut in about equal anterior
                                   and tail portions. One-half of each fish was fried and
                                   the other  half baked, and each of these portions was
                                   subsequently divided into two portions and delivered
                                   warm in aluminum foil to the panel member. All panel
                                   members drank cold milk after tasting each portion to
                                   remove any flavor remaining from a previous sample.

                                      The fish were baked in aluminum foil for 20 minutes
                                   ai an oven temperature  of 350° F.   No seasoning of
                                   any  kind was added  to either the fried or baked fish.
                                   Cracker crumbs were  not used on the baked fish.

                                      Baldwin et  al.  (1961)  determined both aroma,  the
                                   sensation  experienced upon  sniffing as opposed to
                                   ordinary breathing, and  flavor,  defined as the char-
                                   acteristics observed when food is placed in the mouth
                                   and masticated, in a  seasonal study of several species
                                   of fish  from polluted and unpolluted waters.  Aman
                                   (1955)  has pointed out that when we use "taste" we
                                   are  actually referring  to the more inclusive term
                                   "flavor."  In the true "taste" only sweet,  sour, bitter,
                                   and  salt are detected; "flavor" embraces as well the
                                   effect of a substance  on the senses of smell and touch.

                                      Dawson and Harris (1951) thoroughly discuss the
                                   criteria for selecting good panel members and methods
                                   of training. Most of the 12 panel members in this study
                                   appeared  to have  a  real interest  in the project and
                                   had served as panel members the previous year. The
                                   scores  of the  regular panel members were reviewed
                                   after several tasting sessions to determine whether
                                   any  individuals were frequently or consistently off in
                                   their judgments.  Since no such persons  could  be
                                   singled out, the  same people served in subsequent
                                   sessions.

-------
                            Tainting of Fish by Outboard Motor Exhaust Wastes
                                              173
   Each panel member was furnished a card upon which
to record the number of the sample and the date, and
to check one of the following observations on each
sample:

   O - no objectionable taste
   	slightly objectionable taste
   + - strongly objectionable taste
RESULTS AND DISCUSSION

   Summaries of the taste panel's observations during
this  study are given in Tables 1 and 2.  The results
vary  considerably  from week to week so that it is
difficult to see the over-all picture at any given time.
An exception to  this is seen in Table 2; the original
fish in Eggerdlng Pond were suddenly killed on August
11, apparently from  columnaris disease.  The fish
used  to  restock  the  liveboxes on  August 16,  1961,
became tainted  within  35 days  (Sept. 20).  At this
stage,  66 percent of the fish portions fried in vegeta-
ble oil were tainted; wheras 83 percent of those baked
in aluminum foil were tainted.
   When the results  for the total test period were
analyzed,  "slightly  objectionable"  and "strongly ob-
jectionable" were combined as "objectionable."  The
results  were analyzed statistically by the chi-square
test  (Snedecor 1956), in which chi-square = x^ =
/Q _ g\2
-—p.  --- , where O = observed  and  E = expected
(Table  3).  Chi-square  at probability 0.05 for one
degree  of  freedom equals  3.841.  At this level the
chances are only 1  in 20 that the differences in num-
ber  of  positive flavor responses for fish from the
control  and the test ponds occurred by chance alone.
This  level was arbitrarily  selected as the point at
which a difference  would be accepted as real.  The
     Table 1.  SUMMARY OF THE TASTE PANELS' OBSERVATIONS ON THE TAINTING OF BLUEGILLS
              IN OEDER LAKE AS COMPARED TO FISH FROM THE CONTROL POND



Date,
1961
June 27

July 18

Aug. 8


Aug. 23




Sept. 8





Sept. 20









Sourcea and
cooking method
OL-fried
CP-fried
OL-fried
CP-frled
OL-fried
CP-fried
OL(Tank) -fried
OL-fried
OL-baked
CP-fried
CP-baked
OL(Tank) -fried
OL-fried
OL-baked
CP-fried
CP-baked
OL(Tank) -fried
OL(Tank) -baked
OL-fried
OL-baked
CP-fried
CP-baked
OL(Tank) -fried
OL(Tank) -baked
Totals

No objectionable
taste (0)
No. of
portions
34
12
18
9
14
6
7
12
1
10
8
5
7
3
11
8
9
7
9
4
9
9
9
5
226

Percent
94.4
100.0
50.0
75.0
58.3
50.0
58.3
50.0
8.3
83.3
66.7
41.7
58.3
25.0
91.7
66.7
75.0
58.3
75.0
33.3
75.0
75.0
75.0
41.7
62.7
Slightly
objectionable
taste (-)
No. of
portions
2
0
13
3
8
6
4
8
2
2
4
5
4
5
1
2
3
2
2
5
3
2
3
5
94

Percent
5.6
0.0
36.1
25.0
33.3
50.0
33.3
33.3
16.7
16.7
33.3
41.7
33.3
41.7
8.3
16.7
25.0
16.7
16.7
41.7
25.0
16.7
25.0
41.7
26.1
Strongly
objectionable
taste (+)
No. of
portions
0
0
5
0
2
0
1
4
9
0
0
2
1
4
0
2
0
3
1
3
0
1
0
2
40

Percent
0.0
0.0
13.9
0.0
8.3
0.0
8.3
16.7
75.0
0.0
0.0
16.7
8.3
33.3
0.0
16.7
0.0
25.0
8.3
25.0
0.0
8.3
0.0
16.7
11.1
Total
portions
tasted


36
12
36
12
24
12
12
24
12
12
12
12
12
12
12
12
12
12
12
12
12
12
12
12
360
         = Oeder Lake; CP = Control Pond. Fish were from liveboxes, unless Tank is indicated.

-------
174
ENVIRONMENTAL REQUIREMENTS OF FISHES AND WILDLIFE
results  of  both  the fried-fish and  the  baked-fish
testing procedures for the entire season were analyzed
as a group for each of the test ponds.

   The  tainting  results  for  fish  from Oeder Lake
(motor  lake)  and the control  pond that  were fried
had a chi-square value of 4.4425  (Table  3, A)0  The
probability that the  differences occurred by chance is
quite low.  The  overall results with the baked fish
procedure that was started late in August, showed a
chi-square value of 12.74 (Table 3,  B), which indicates
that the probability of the differences occurring  by
chance alone is very remote. The greater value may
be  due  in  part to  the fact that the fish had been
exposed for several weeks to water polluted by out-
board motor exhaust wastes before the baking tests
were started.

   The total results for fish from the 500-gallon tank
set up on the dock at Oeder Lake July 11 showed a
chi-square value  of 1.74 for the tried fish and 3.08 for
the baked fish, Table 3portions, C andD, respectively.
Both of these values are below the 3.84 value that was
                                  initially  adopted  as the  criteria for a  significant
                                  difference, but the  exposure time was  6  weeks less
                                  than for Oeder Lake livebox fish.

                                     In Eggerding  Pond (motor pond) where  outboard
                                  motors were operated a known length of time and fuel
                                  consumption was  measured, the results were striking
                                  in spite  of the difficulties encountered in maintaining
                                  fish.  Table 3 shows the results for the entire season.
                                  Bluegills were stocked in the liveboxes in  that pond
                                  June 29.  In a little more than a month, 75 percent of
                                  the fish portions tasted by the  panel showed some
                                  degree of tainting.  After columnaris disease  or out-
                                  board motor exhaust wastes wiped out the initial stock
                                  of bluegills in the liveboxes, wild  fish seined from the
                                  pond  with  considerable  difficulty because  of their
                                  scarcity, were sampled August 17 and 23. On August
                                  17, 65 percent, and on August 23, 50 percent of the
                                  portions of  fried wild fish (bluegills outside the live-
                                  boxes) were tainted.   On August 23, baked portions
                                  of the same fish showed 83 percent tainted.  Bluegills
                                  seined from the  pond  on June  26, 1962, prior to the
                                  operation of outboard motors, and fried showed no
                                  tainting.
   Table 2. SUMMARY OF THE TASTE PANELS' OBSERVATIONS ON THE TAINTING OF BLUEGILLS IN
            EGGERDING POND AS COMPARED TO FISH FROM THE CONTROL POND



Date,
1961
Aug. 3

Aug. 17


Aug. 23





Sept. 20



Sept. 29







Source3- and
cooking method
EP-fried
CP-fried
EP-fried +
Wild fish c
CP-fried
EP-fried +
Wild fish
EP-baked +
Wild fish
CP-fried
CP-baked
EP-fried
EP-baked
CP-fried
CP-baked
EP-fried
EP-baked
CP-fried
CP-baked
Totals

No objectionable
taste (0)
No. of
portions
3
8

8
12

6

2
0
8
4
2
9
9
6
1
8
8
104

Percent
25.0
66.7

34.8
100.0

50.0

16.7
83.3
66.7
33.3
16.7
75.0
75.0
50.0
8.3
100.0
66.7
52.3
Slightly
objectionable
taste
No. of
portions
3
4

7
0

3

6
2
4
3
5
3
2
2
1
0
4
49
(-)

Percent
25.0
33.3

30.4


25.0

50.0
16.7
33.3
25.0
41.7
25.0
16.7
16.7
8.3
0.0
33.3
24.6
Strongly
objectionable
taste (+)
No. of
portions
6
0

8
0

3

4
0
0
5
5
0
1
4
10
0
0
46

Percent
50.0
0.0

34.8


25.0

33.3
0.0
0.0
41.7
41.7
0.0
8.3
33.3
83.3
0.0
0.0
23.1
Total
portions
tasted


12
12

23 b
12

12

12
12
12
12
12
12
12
12
12
8
12
199
      a EP = Eggerding Pond; CP = Control Pond. Fish were from liveboxes, unless otherwise indicated.

      b Observation missing.

      c Wild fish in pond sampled when columnaris disease killed all fish held in liveboxes and most of the
       fish in the pond. Liveboxes restocked Aug. 16, 1961, with adult bluegills.

-------
                         Tainting of Fish by Outboard Motor Exhaust Wastes
                                              175
      Table 3.  RESULTS OF CHI-SQUARE ANALYSIS OF THE TASTE PANELS' OBSERVATIONS ON THE
               TAINTING OF BLUEGILLS (held in liveboxes) BY OUTBOARD MOTOR EXHAUST WASTES

                   (Significant chi-square at probability P-0.05 with one degree of freedom - 3.84)

A. Oeder lake (motor lake)
compared to control pond
(fried)
Control pond (no motors)
Oeder lake
Totals
B. Oeder lake compared to
control pond (baked)
Control pond
Oeder lake
Totals
C. Oeder lake tank compared
to control pond (fried)
Control pond
Oeder lake
Totals
D. Oeder lake tank compared
to control pond (baked)
Control pond
Oeder lake tank
Totals
E. Eggerding pond (motor pone
compared to control pond
(fried)
Control pond
Eggerding pond
Totals
F. Eggerding pond compared
to control pond (baked)
Control pond
Eggerding pond
Totals

Total portions
untainted
Observed
57
94
151

23
8
31

36
30
66

17
11
28
)
47
27
74

25
5
30
Expected
50.3
100.7


15.5
15.5


33
33


14
14


30.4
38.6


15
15


Total portions
tainted
Observed
15
50
65

13
28
41

12
18
30

7
13
20

9
44
53

11
31
42
Expected
21.6
43.2


20.5
20.5


15
15


10
10


23.4
29.6


21.5
21.5

Total
portions
tasted

72
144
216

36
36
72

48
48
96

24
24
48

56
71
127

36
36
72

Chi-square
observed



4.425 a



12. 74 a



1.74 b



3.084b



20.80 a



22.67 a
         a Significant values.
         b Not significant. Tank fish exposed for period of 6 weeks less than livebox fish in Oeder Lake.
   The  chi-square  test applied  to  the  total fried
portions of fish taken from inside  or  outside the
liveboxes in Eggerding Pond showed a high chi-square
value of 20.8 where significance  at the  95 percent
confidence  level was 3.84  for one degree of freedom
(Table 3,   E).  When the fish were baked, even more
striking results were  obtained  (Table  3,  F), with
the  highly  significant  chi-square value of 22.67.

   The  level  of fuel  consumption per acre-foot of
water at which fish flesh tainting becomes evident is
probably influenced by the daily average rate at which
fuel  is used in motors operated on the pond.  Figure
1  shows that the  fuel use  rate in Oeder  Lake was
fairly  steady  throughout  the season; the fuel con-
sumption rate for the two operating periods in Eggerd-
ing  Pond  was also uniform when considered on a
weekly basis.  Thus tainting results at two fuel use
rates are  available.  At the fuel use rate in Oeder
Lake the first  indications of tainting occurred be-
tween the consumption of  2.2 and 3.5 gallons of fuel
per  acre-foot of  water.    At  the  fuel  use rate in
Eggerding Pond fish flesh tainting was severe at the
first observation made; fuel consumption up to this
time was 5.9 gallons per acre-foot.

   An  estimate  of the threshold level of fuel con-
sumption for  tainting was made  as follows. All tests
of the  fried control fish averaged 18 percent positive
responses.  A graph was made by plotting the percent
positive  responses in  fish  tainting tests against
cumulative fuel  use.  The positive baseline level of
18 percent for the control was found on this graph to
correspond  to a fuel consumption of 2.6 gallons per
acre-foot of water in  Oeder Lake.   This appears to
be the  best estimate that can  be  made  of the level

-------
176
ENVIRONMENTAL REQUIREMENTS OF FISHES AND WILDLIFE
at which  motor use should be  restricted to avoid
fish  tainting; it is considered applicable to a rate of
fuel  use that consumes this quantity over a 2-month
period.
   The  hours of operation and fuel consumption rate
of two sizes of outboard  motors required for signi-
ficant  tainting  of  fish  are illustrated in Table  4.
 Table 4.   HOURS OF OPERATION OF OUTBOARD
           MOTORS (per acre foot of water) RE-
           QUIRED FOR SIGNIFICANT TAINTING
           OF FISH

5 HP
50 HP
Water surface
area per boat,
sqft
Depth of water, ft
Motor operation
per day, hr
Fuel consumption
gal per hr
Period, days
Gal of fuel per
acre ft
Estimated fuel
consumption
rate, gal
per hour
1/2
5
Extreme
0.92
40,000 (acres)
5
2
1 1/2 5
90 90
19.6 196
Hours of operation,
in acre feet of
water, for 2.6 gal
of fuel use
5.2 hr
0.52 hr
Critical
5.7
250,000 (acres)
10
2
1/2 5
90 90
1.6 16
   Because of the possibility that the outboard motor
exhaust wastes might be  injurious to  the red blood
cells, examinations for haemoglobin were made of the
blood of bluegills from both the control and experi-
                                mental ponds.  These examinations failed to show a
                                significant trend.
                                ACKNOWLEDGMENTS

                                   Mr.  Lester Oeder, Morrow, Ohio, permitted the
                                use of Oeder  Lake and a farm pond on his property
                                for the  conduct of this experiment.  The Eggerding
                                Brothers, Red Bank Road, Cincinnati, consented to the
                                use of their pond for the experimental operation of
                                outboard motors.

                                   The  following  persons  of  the  Robert  A.  Taft
                                Sanitary  Engineering Center  staff  served on the
                                taste  panel of  12 persons or were "standby" for the
                                regulars: Dr. Louis Williams, Dr. Clarence Tar zwell,
                                Dr. C. Mervin Palmer, Mrs. Carol Scott, Julia Air,
                                Albert Katko,  Mrs.  Eva Morgan, Thomas  Maloney,
                                Mary-Ellen Morris, Quentin Pickering, Ernest Robin-
                                son, Mrs. Edith Smith, Robert Davis, Edwin Earth,
                                Richard Games, Dr. Donald Mount, Gerald McDermott,
                                and John English.

                                   Julia Air and Mrs. Eva  Morgan served as cooks
                                during the project and Quentin Pickering and Richard
                                Carnes  seined fish and prepared them for  cooking.

                                   Dr. Donald  Mount made  the haemoglobin tests on
                                samples of fish from the control  and experimental
                                ponds.

                                   Dr. Eugene K. Harris, Chief, Statistical Services,
                                reviewed the report and offered suggestions.
                                Special  acknowledgment  is  made  of the work of
                                Robert Breinich, a promising student at Villa Madonna
                                College, Covington, Kentucky, and a hard-working and
                                faithful  assistant on this project up to the time of his
                                untimely death.
                                   Adult  bluegills  for  these  tests were obtained
                                through  the  cooperation of the Ohio Department of
                                Natural Resources, Division of Wildlife; the Kentucky
                                Department of Fish and Wildlife Resources; and Dr.
                                Charles  Hauser of Glendale, Ohio.
                                             REFERENCES
Aman,  C.W.  1955.   The relation of taste and odor
to flavor. Taste and Odor Control Journal, 21 (10) :l-4.

Baldwin,  Ruth,  E.,  Dorothy H.  Strong,  and James
H. Torrie 1961.  Flavor and aroma of fish taken from
four fresh-water sources.  Trans. Amer. Fish. Soc.,
P0(2):176-177.
California Dept. of Public Health, Bureau of Sanitary
Engineering 1961.  A  study of recreational use and
water  quality  of reservoirs (1959-1961),  62 p., Ap-
pendices A,B,C - Multilithed Report.

Dawson, Elsie H. and Betsy L. Harris 1951. Sensory
methods for  measuring differences in food quality.
U.S. Dept.  of Agric., Agriculture  Information Bull.
No. 34, 134 p.

Davis, James T. 1960.  Fish populations and aquatic
conditions in polluted waters in Louisiana. La. Wild-
life and Fisheries Bull. No.  1, 1960, 121 p.
                                 English, John N., Gerald N. McDermott, and Croswell
                                 Henderson 1961.  Can outboard motor exhaust signi-
                                 ficantly pollute  water?  Presented at Central States
                                 Sewage and  Industrial Wastes Association Meeting,
                                 Springfield, Illinois, June  7-9, 1961.  Mimeographed
                                 Public Health Service Report, 14 p.

                                 Shea,  John G.  1961.   Let's not legislate ourselves
                                 out of the water. Motor Boating. Sept. 1961. pp 18, 74.

                                 Snedecor,  George W. and  William G. Cochran 1956.
                                 Statistical methods.   (Fifth Edition) The Iowa State
                                 College Press, Ames, Iowa, 534 p.

                                 Winston, A.W.,  Jr. 1959.   Test for odor imparted to
                                 the  flesh  of  fish.   Second Seminar on Biological
                                 Problems  in  Water  Pollution (unpublished).  April
                                 20-24,  Cincinnati, Ohio.  Sponsored by U.S. Public
                                 Health Service.

-------
                                   Effects of Oil Pollution on Migratory Birds
                                               177
                           EFFECTS OF OIL POLLUTION ON MIGRATORY BIRDS
                                             Ray C. Erickson *
   Among the factors adversely affecting the welfare
of migratory birds  is  oil pollution,  a spectacular
and  frequently  observed cause  of  bird mortality.
Much has been  written about these losses, but most
reported instances of oil-caused mortality have been
based on localized or short-term observations.  No
comprehensive  annual  surveys  of  migratory bird
casualties to oil  pollution have  been made for  the
entire coast of the United States.

   Among  the  more local  or short-term studies,
Tuck (1960) included an excellent report of the effects of
oil pollution  on oceanic, migratory  birds along  the
coast of Newfoundland.   Miller and  Whitlock (1948)
described waterfowl mortality from oil contamination
on the Detroit River, while  about 10 years earlier,
Moffitt and  Orr (1938) reported similar losses with
waterfowl  and  other migratory  birds in the  San
Francisco Bay region.  More  general but neverthe-
less valuable statements on the  overall problem of
oil  contamination  and  migratory birds  have been
presented by Lincoln (1936), Belt (A report to The
International Committee for Bird Preservation, "Oil
Pollution", dated October 27, 1953, London, England),
Giles and Livingston  (19CO), Hawkes (1961), and U.S.
Coast Guard (1961).  Other published articles of im-
portance in understanding the  problem, but not pri-
marily concerned with the effects of oil pollution on
migratory birds and other wildlife, are by California
State Water  Pollution Control Board  (191,5, 1959),
Gutsell  (1921),  Lane et  al. (1925),  Galtsofi (1936),
Galtsoff et al.(1935), Gunter (1959), and Dennis (1959:
1960a; 1961). Although  the  oil pollution problem is
largely  man-made, natural  oil seepages have been
reported off "... the southern coast of California, in
the western Gulf of Mexico, off the eastern coast of
Texas and Mexico, along the coast in parts of western
and northern Cuba" (Dennis, 1959).

   The fossilized remains of prehistoric  animals in
the natural asphalt deposits at Rancho  LaBrea, Calif-
ornia, show that oil-caused wildlife  mortality is  not
a  new problem.  Widespread  losses  did  not occur,
however,  until well  into the present century when
petroleum fuels became  more  extensively exploited
for oil-burning ships, automobiles, locomotives, air-
planes,  stoves,  and  furnaces; black-top roads, and
many other uses.  Oil may become a mortality factor
when spilled  into  wildlife environments at the site
where it is  extracted from the ground  or anywhere
along the line to  its final  destination and use.

   Nearly every body of  water  on  earth,  fresh or
salt, is occupied by  migratory  birds  at one time or
another.   The potential for losses of  migratory fowl
thus exists  almost everywhere that surface waters
are  contaminated by oil.  In North America, greatest
losses of migratory birds  to oil pollution have been
observed along the coast and in offshore waters of
the Atlantic Ocean and, to a  lesser extent, the Gulf
of Mexico  and the Pacific  Ocean. Losses have been
particularly heavy  in  or adjacent  to the principal
harbors  and oil refineries of the Northeast and along
the more heavily traveled  shipping lanes. The pro-
blem has  also  been encountered in various inland
waterways including the  Great Lakes.  This  region
is being watched with some concern  because of the
opening of the St. Lawrence Seaway in 1959 to inter-
national deep-draft shipping (Dennis, 1960b).

SCOPE OF PROBLEM

   Oil contamination in habitats utilized by migratory
birds  may be detrimental at any time of the year.
Apart from the aesthetic damage, losses may occur
during the colder months when greatest numbers of
birds are present, or during the growing season when
oil may  blanket the shores or bottom and reduce or
eliminate important sources of  food.  It is  the oil
spillage  during the seasons and in the areas of heavy
migratory  bird use that brings about the spectacular
losses reported in the  press. Because spillage often
occurs in or near human population centers along the
coast, especially in bays and harbors, losses to coastal
dwelling wildlife are much more likely to be observed
than  mortality of offshore pelagic forms that come in
contact with oil out at  sea and die unnoticed. Birds
that  are year-round residents along the coast would
appear to be highly vulnerable, for they must survive
a much greater period of direct exposure to oil each
year  than those  that  appear briefly as migrants.

   It  is extremely difficult to assess  the importance
of oil pollution-caused mortality in  most wildlife
populations.   This is particularly true with the very
mobile forms. Movements of population units through a
contaminated location and various other factors make
it  difficult to measure what  proportion of the total
population  has come in contact with oil, and, of the
segment that has, what proportion is lost.

   It is almost certain that relatively few of the birds
that  contact oil and die far out to sea are observed.
The  proportion that ultimately drifts to the coast and
is seen depends upon air and water currents, the period
during which the carcasses remain afloat and on the
beach, frequency of surveillance  of drift  materials,
and  other  factors.   Estimates  of  mortality based
oa observed remains of oil-soaked  birds, ordinarily
have  value, therefore, only as minimal indications of
loss,  because the elements that singly or in combination
operate to  obliterate the  evidence may be extremely
* U,S Fish and Wildlife Service, Washington, DC

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178
ENVIRONMENTAL REQUIREMENTS OF FISHES AND WILDLIFE
varied in their ultimate effects. Because many other
mortality factors face migratory birds, especially
those species that must survive semiannual flights and
an annual hunting season, the importance of pollution-
caused mortality in the overall scheme  of manage-
ment and preservation of some species is difficult if
not impossible to assess accurately. Wide dispersal
of a population may spread the risk and be safer  than
concentration of  the entire species in  a limited lo-
cation.   Also,  mobility and versatility  in food accep-
tance may allow a species to use alternate habitats
when preferred environments are contaminated.

EFFECTS ON BIRDS

   Large numbers and varieties of birds are involved
in the oil pollution problem.  Most, if not all, of the
migrants that alight on the open sea, that feed or  rest
in coastal bays or estuaries and on inland waters, or
that move up and down the beach are subject to oil
contamination. Birds may also become oiled in borrow
pits adjacent to freshly  surfaced  highways,  or on
polluted ponds associated with oil wells, pipe lines, and
refineries.   The possibility has been  suggested that
birds  such  as ducks or  gulls are attracted to oil
slicks because the  quieting effect of  the slicks on
choppy waters may falsely  suggest  the presence  of
submerged vegetation or  shoals of fish (Tuck, 1960).
Since  it has not yet been  demonstrated that birds
actually  are  attracted to  oil, it may be that the  con-
tamination of migratory birds occurs  when they are
drawn to the  areas for  feeding,  resting,  or other
purposes.

   Among  the birds  most  commonly affected are
common and red-throated loons, greater scaup, eiders,
scoters, oldsquaw ducks, American goldeneyes,  var-
ious  gulls,  common  and  thick-billed murres,  and
razorbill auks, though other  species of  loons, grebes,
shearwaters, fulmars, petrels, ducks and geese, terns,
other shorebirds, auks, dovekies,  murrelets, guille-
mots, and puffins are included on the  casualty  list.
In general,  records of oil pollution casualties  show a
relation between the amount of time that migratory
birds  spend  in  the  water  and  frequency of  con-
tamination.  As examples, murres spend most of their
time in the water when not at the nest and are subject
to  extensive  losses,  while  gulls, though extremely
abundant in  harbors and other coastal areas where
oil pollution  is  common, seem better  able to with-
stand the adverse effects.  This may stem from their
inclination to  spend much of their time away from
water or in the shallows where their  feet,  rather
than  their plumage, are more likely to come in  con-
tact with oil (Moffitt and Orr, 1938), or  their ability
to regurgitate ingested materials.  On the other hand,
some  observers believe  that  gulls are inherently
better able to withstand actual fouling by oil than are
most other types of migratory birds.

   The direct  effects of  oil  on birds  depend  upon a
variety of factors, including the type of oil, extent of
contamination of plumage, temperatureof airand water,
and probably the quantity  of oil ingested. In general
the heavier oils are a greater problem than the more
volatile  and  are  readily   dispersed  types.    Even
small quantities of oil may destroy the waterproof
                                 qualities of plumage  and permit chilling by water or
                                 air,  especially during the coldest months.  The oil
                                 may not only  saturate  the  outer contour feathers,
                                 but also penetrate the downy layer of ducks and other
                                 birds that  have  this  natural insulation. Soaked  with
                                 oil and water,  the bird loses its buoyancy and  ability
                                 to fly, and can no longer feed effectively.  Continued
                                 exposure to the cold and reduced ability to obtain  food
                                 or depart for more habitable surroundings, render the
                                 bird incapable  of  maintaining body temperatures and
                                 surviving.

                                    It  should not be  inferred  that all birds coming
                                 in contact  with oil are doomed. On the contrary, the
                                 number that die may be considerably smaller  than
                                 the number  that  survive.   In areas of  chronic oil
                                 pollution in  the Northeast,  hunters  are  reported  to
                                 have  encountered "oil-burn* on as many as  half  of
                                 the scoters they bagged. One game management agent
                                 of the Bureau of Sport Fisheries and Wildlife reported
                                 finding extensive, heavy oil  contamination  on the
                                 plumage of 5 percent  of all scaup in the hunter's  bags
                                 he examined.  Many  hunters are reluctant to use oil-
                                 stained birds for  food and may throw them away  or
                                 not even bother to take them into possession because of
                                 the actual  cr imagined tainting of flesh.  Because oil
                                 often is ingested in the preening process, palatability
                                 of contaminated ducks may be reduced, especially if
                                 the birds  are not dressed soon after  being  shot.
                                 Furthermore,  if their  feeding activities have  been
                                 hampered, they may be in poorer  flesh and  less
                                 desirable for the  table  than birds that have not en-
                                 countered oil.

                                    Little is known about the toxic effects of ingested oil
                                 on migratory birds, except that the alimentary tracts
                                 of some victims have become literally lined with res-
                                 idues.   Under  these  circumstances,  they usually
                                 have  been in  poor  flesh.   The rate at which the
                                 digestive  system  is  cleared by voiding this material
                                 is not known, but most birds that have swallowed oil
                                 have little  else in their stomachs.

                                    Migratory birds are indirectly  affected by deposits
                                 of oil on the bottom in shallow water or along the shore
                                 that reduce  the available  food supply of both  plant
                                 and  animal  matter.    Various  elements  in the  food
                                 chains   are eliminated by chemical and  physical
                                 properties  of  the  oil,  or  items of the diet  may be
                                 made  unavailable by being  overlaid or imbedded in
                                 tarry materials. The use of important feeding grounds
                                 has declined greatly after pollution by oil, either be-
                                 cause of the elimination of essential food and cover,
                                 or because fouling of  the habitat in  other ways has
                                 reduced the  attractiveness of the areas.  Shorebirds
                                 that rely upon the intertidal zones for their feeding
                                 grounds may find them completely blanketed with oil.

                                    It  seems  likely that  oil poses  the greatest hazard
                                 to wildlife at  the time it escapes or is  spilled into
                                 aquatic and marine  habitats.   As it  continues  to be
                                 exposed to the action  of  water, air, bacteria, and
                                 other  agents,  it  loses  certain volatile components.
                                 The  remaining, increasingly viscous residue  may
                                 eventually  take the form and consistency of  a firm,
                                 asphalt-like matrix containing shells, sand, and other
                                 debris.  Dennis (1959)  has  classified oil forms into

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                                 Effects of Oil Pollution on Migratory Birds
                                               179
five types, and has indicated that some oils progress
more  rapidly than others to the solid stage.  Oils,
when firm,  no longer adhere to the plumage of birds.
In the more stable and durable stages, oil residues
may  last for months  or even  years, but with re-
duced likelihood  of adversely  affecting migratory
birds.   Accumulations  of  petroleum  sludge  may,
however, prevent germination and growth of plants and
the production of  invertebrates  important as food,
either by blanketing the  bottom or by toxic  effects.


                    DISCUSSION
   Although the  oil pollution problem is not new,
little intensive  study  of its ultimate  effects on mi-
gratory bird species and populations has been made.
Oil  pollution  affects  different species  in  various
ways depending upon the extent of the polluted area,
and  the  habits,  numbers,  and distribution of  birds
using the contaminated habitats.  It is likely to pose
a spscial hazard for species that occupy, during any
part of  the year,  a very limited range susceptible
to oil pollution.   Two noteworthy  examples of this
type of  vulnerability  are  the  greater snow goose,
which  winters on  the  Outer Banks of Virginia and
North Carolina, and the whooping crane, which winters
almost  exclusively in  the  Arkansas  National Wild-
life  Refuge  and vicinity on the Gulf Coast of Texas.


   With  abundant and  widely distributed  forms, oil
pollution may serve as an  agent of intermittent  but
continuing  attrition,  especially  on those migratory
birds  using  coastal  and  offshore waters.   Most
pollution-caused losses  occur  during the  coldest
months when  the  birds  are abundant and are con-
centrated on  stopover points  or on  the  wintering
grounds.    Losses under these  circumstances are
especially important because they involve the  birds
that  have already survived the southward flight and
hunting season  and that have  become the potential
breeding stock for the next nesting season.

   Because  of the importance  of oil pollution from
the standpoint of wildlife losses, and from aesthetic
and economic  considerations, much public interest has
arisen concerning  what may  be done about it.  Ob-
viously,  eliminating sources  of pollution would solve
the  problem.    Ratifying and strictly enforcing  the
provisions of  the 1954 International  Convention  for
the Prevention of the Pollution of the Sea by Oil as
amended in 1962, and of existing regulations on oil
pollution in domestic waters under the jurisdiction
of the nations of North America  would  be  another
step in this direction,  at least insofar as our native
migratory  birds are  concerned.   Even  with strict
enforcement  and  observance  of  such regulations,
it is unlikely  that  complete cessation of oil pollution
will  result, because shipping accidents,  oil line or
installation defects, and other human error and equip-
ment failure factors will undoubtedly  continue. En-
actment  and enforcement of  stricter  laws by States
and local governments are especially important, since
a 1960 survey showed  a  lack of  effective local laws
to be a particularly weak link  in the problem of oil
pollution control.
   Through the years,  various methods have been
tried for  eliminating oil slicks,  including  the use
of  carbonized  sand,  solvents,  emulsifiers,  deter-
gents, and burning.   Some of them have had value
for neutralizing or preventing  the spread of  local or
semi-contained foci  of  contamination.  Ordinarily,
however,  the  oil disperses rapidly to form an exten-
sive, thin  film.  After this has occurred, treatment
requires extensive and costly coverage, so  that the
only  complete  solution consists in  preventing  the
initial release of the oil by  good seamanship, pre-
ventive maintenance, and strictly observing  regula-
tions for  releasing pollutants, including effectively
treating  oily wastes.  To out knowledge, no econom-
ical yet efficient technique  is available for elimi-
nating sludge  deposits that may develop where waste
oil has settled, though modest  success has been re-
ported on the use of emulsifiers in Great  Britain.

   Action  to  reduce the  adverse effects of  oil pol-
lution  at  the  point of damage to  wildlife admittedly
is not a satisfactory solution to the problem though
it may help  to  save some  birds,  permit the pro-
tection  or rehabilitation  of habitat,  and provide the
basis for participation of private individuals and or-
ganizations interested in the humanitarian aspects of
this work.  Unfortunately, by the time that contami-
nated birds can be captured, many, if not most of them,
are  beyond assistance because of  external injury,
toxic effects,  exposure, or  starvation.   It is  not
economically  feasible to  patrol, with sufficient fre-
quency  and thoroughness to pick up contaminated
birds in  time to save  them,  all the vast expanses
where migratory birds may encounter oil. Also, the
decontamination and rehabilitation processes now in
use are rather laborious and time-consuming, so that
costs of treatment remain high.

   Many methods  of removing  oil or tarry  deposits
from waterfowl plumage have  been  tried.   Various
solvents have been in use for  more than a score of
years.  Although the oil  may be removed, consider-
able irritation of  the skin usually results and loss of
natural oils from the plumage often requires re-
taining the  bird a week or more in  captivity before
it can be  safely  released.   Soap and water is in-
effectual under most circumstances.  Use of a "dry
shampoo"  of  Fuller's Earth  or powdered chalk has
been  described  by  Mrs.  Catherine  Tottenham  of
North Devon,  England (letter of January 25, 1958 to
Dr.  Frederick  C. Lincoln,  U. S. Fish and  Wildlife
Service).   With especially  difficult cases, she pre-
ceded  the  Fullers Earth treatment  with  a  liberal
application of butter on the  plumage, a warm, soapy
bath, and overnight  drying.   In his letter of June 30,
1952, to  Mr.  Francis B.  Schuler of the Bureau of
Sport Fisheries and Wildlife, Dr. Oliver H.  Hewitt,
of  Cornell  University, reported  a  similar  method
suggested  by  Dr. D. F. Steadman, involving three
formulas  of nontoxic ingredients  including corn oil,
neat's-foot oil, oleic  acid, paraffin,  a  solvent, two
commercial detergents with  the trade names "Span
40" and  "Tween 40", and water. These preparations
were used  successfully  to decontaminate ducks that
became  severely  oiled  in  1948  when a tanker ran
aground  in the St.  Lawrence River.   They were
applied, then wiped off after a minute of two, followed

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 180
ENVIRONMENTAL REQUIREMENTS OF FISHES AND WILDLIFE
by successive applications  as necessary. The birds
were kept  10  days before release to the wild fully
recovered.

NEEDED RESEARCH

   There are several promising lines of wildlife re-
search that should be  considered from the stand-
point of obtaining a more accurate appraisal of the
significance of the effects of oil pollution on mi-
gratory bird populations and their habitats, and in the
development of more efficient methods of decontamina-
ting the birds and their environments.

   (1)   An initial step would be the development of a
systematic  surveillance of sites  of chronic  oil pol-
lution,  as well as of accidental and unusual releases
of oil  in areas of intensive use by migratory birds,
coupled with stricter enforcement of existing laws.
Information from this survey would be useful in pin-
pointing sources of pollution important to these birds
and  might  help  to  indicate  the  significance of the
impact of oil contamination on this resource.

   (2)    Study of the behavior of migratory  birds in
the vicinity of  oil spills, accidental or experimental,
                                 and development of methods for preventing birds from
                                 alighting in  the  contaminated  areas.  The use  of
                                 frightening devices such as floating rotating beacons,
                                 exploders,  flashers,  dyes, and other methods  found
                                 effective  in  prevention  of waterfowl  depredations
                                 should be tested.
                                    (3)   Further development and  testing  of methods
                                 of decontaminating  and reconditioning wildlife suf-
                                 fering from  contact with  oil pollution, with special
                                 attention to techniques that might be used by private
                                 citizens or organizations  having a minimum of ma-
                                 terials, equipment, facilities, and training.
                                    (4)   Studies of the short- and long-term effects
                                 of oil pollution on plants and animals important to
                                 migratory birds and other wildlife and fish as food
                                 or cover. Determination of the mechanics of damage
                                 and  the  extent to which  alteration  of the habitat
                                 modifies its use and value  to wildlife.

                                    (5)    Development and testing  of  techniques  of
                                 reconditioning  wildlife habitats that have been sub-
                                 jected to  oil  pollution,  as by  changes in  water
                                 management  practices, mechanical and chemical de-
                                 contamination methods, and vegetation plantings, fol-
                                 lowed by evaluations of wildlife response.
                                               REFERENCES
California State Water Pollution Control Board. 1956.
Report on  oily substances and their  effects on the
beneficial uses of water.   Publication No.  16, 72 p.

California State Water Pollution Control Board. 1959.
(2 parts)  Part I:   Determination of the quantity of
oily substances on beaches and in nearshore waters,
46  p.   Prepared  by Sanitary Engineering Research
Laboratories of the University of Southern California,
Los Angeles,  California;  and Part IT.  Character-
ization of coastal oil pollution by submarine seeps,
pp. 47-61.  Prepared by the Robert A. Taft Sanitary
Engineering Center, USPHS, Cincinnati, Ohio.
Chipman,  Walter  A.  and  Paul  S.  Galtsoff.   1949.
The effects of oil  mixed  with carbonized sand on
aquatic animals.  Special Scientific Report Fisheries
No. 1, Fish and Wildlife Service, USDI, 81 p.

Dennis,  John  V.  1959.  Oil  pollution survey of the
United States Atlantic  Coast,  with special reference
to  southeast  Florida  coast  conditions.   American
Petroleum Institute, Division of Transportation, Wash-
ington, D. C., 46 p.

Dennis,  John  V.   1960a.   Oil pollution  conditions
of the Florida east coast.   American Petroleum In-
stitute, Division of Transportation, Washington, D.C.,
7 P.
Dennis,  John  V.  1960b.   Oil pollution survey of the
Great  Lakes.  American Petroleum Institute, Division
of Transportation, Washington, D. C., 22 p.

Dennis, John V. 1961.  The relation of ocean currents
to  oil  pollution.   American Petroleum  Institute,
Division  of Transportation, Washington, D. C., 30 p.
                                 Engineering—Science, Incorporated.  1960. Analytical
                                 characteristics  of oily substances found on southern
                                 California beaches.   Mimeographed  report prepared
                                 for  the  Western Oil and  Gas Association,  50 p.
                                 Engineering—Science,  Inc., 150  E. Foothill Blvd.,
                                 Arcadia, California.

                                 Galtsoff,  Paul  S., Herbert F. Prytherch, Robert O.
                                 Smith, and Vera Koehring.  1935.   Effects of crude
                                 oil pollution on oysters in Louisiana waters.  Bulletin
                                 No.  18  of the  Bureau  of Commercial  Fisheries,
                                 Vol. XLVHI, p. 141-210.
                                 Galtsoff,  Paul  S.   1936.   Oil pollution  in coastal
                                 waters.   Proceedings of North  American  Wildlife
                                 Conference on   February  3-7, 1936,  p.  550-555,
                                 Washington, D.  C.,  Committee Print, 74th Congress,
                                 2nd Session.

                                 Giles Jr., Lester A. and John A.  Livingston.  1960.
                                 Oil pollution of the seas.  Trans. 25th North American
                                 Wildlife Conference, p. 297-303. Wildlife Management
                                 Institute, Washington, D. C.

                                 Gunter, Gordon.   1959.   Pollution problems along
                                 the  Gulf  coast.   Transactions of 1958 seminar on
                                 "Biological problems in water pollution."  The Robert
                                 A. Taft Sanitary Engineering Center. Technical Report
                                 W60-3, Cincinnati, Ohio, p. 184-188.

                                 Outsell,  J. S.    1921.  Danger to  fisheries from oil
                                 and  tar  pollution of  waters.   Bureau of Fisheries
                                 Document No. 910, p. 3-10.

                                 Hawkes,  Alfred  L.    1961.  A review of the nature
                                 and  extent of  damage caused by  oil pollution at
                                 sea.  Transactions  of the 26th North American Wild-
                                 life  Conference, p.  343-355.   Wildlife Management
                                 Institute, Washington, D. C.

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                     Factors That Affect the Tolerance of Fish to Heavy Metal Poisoning
                                               181
Lane,  F. W.,  A. D. Bauer, H.  F. Fisher and P. N.
Harding.   1925.   Effect  of oil pollution on marine
and  wildlife.   Bureau of Fisheries  Document  No.
995, p. 171-181.

Lincoln,  Frederick  C.   1936.   The  effect  of oil
pollution on waterfowl. Proceedings of North American
Wildlife Conference of February 3-7,1936. Commitee
Print, 74th Congress, 2nd Session, p. 555-559.

Lincoln, Frederick C. 1942. Treatment of oil-soaked
birds.   Wildlife  Leaflet  221,  Fish and  Wildlife
Service, U. S. D. L, 2 p.

Miller,  Herbert J. and S. C. Whitlock. 1948.  Detroit
River waterfowl  mortality — winter 1948. Michigan
Conservation, vol. XVTI, No. 4, p. 11-15.
Moffitt, James, and  Robert T. Orr.   1938.  Recent
disastrous effects of oil pollution on birds in the
San Francisco Bay region.  California Fish and Game
24, No. 3, p.  239-244.

Tuck,  Leslie M.  1960.  The  murres—their distri-
bution, populations and biology, a study of the genus
Uria.    Canadian  Wildlife  Series:    1  Department
of Northern Affairs and National Resources, National
Parks Branch,  Canadian  Wildlife Service,  Ottawa,
Ontario, Canada, 260  p.

U.  S.  Coast Guard.   1961.  Pollution of the Sea by
Oil. Reply of the U.S.A. to questionnaire on pollution
of the sea by oil received from the Intergovernmental
Maritime  Consultative Organization  as Annex  "A"
to their document vol. VH, dated 26 August 1960,
16  p.  D  Department of  State,   Washington,  D.  C.
                             FACTORS THAT AFFECT THE TOLERANCE OF FISH

                                     TO HEAVY METAL POISONING

                                              Richard Lloyd *
                 INTRODUCTION

   A critical review  of the literature on the toxicity
of the heavy metals  to fish,  compiled by Doudoroff
and  Katz  (1953),  showed  clearly that there  were
considerable differences among the concentrations of
a single metal found by different authors to be toxic
to fish.   It appeared that differences in the test
conditions, such as the nature of the dilution water,
the duration of the test, and the species of fish used,
contributed to the wide  variation  in  the  results.
Factors such as temperature  and the concentration
of dissolved gases  and calcium in the dilution water
had been  shown to  modify the amount of heavy metal
required to kill fish.  These experiments had, how-
ever, shown only the qualitative importance of these
factors; there were few quantitative results.

   If the  -results of toxicity tests made in the labo-
ratory   are  to  be  applied  to the  control of stream
pollution,  the effects of the important environmental
variables  found in  natural  waters have to be quan-
titatively  assessed.  This paper reviews some of the
work done  at  the  Water  Pollution  Research  Lab-
oratory, England, on this problem.

      MODE OF ACTION OF HEAVY METALS

   Many  early  workers attributed  the toxicity of
heavy  metals to the precipitation of mucus on the
gills of the fish, but it was later suggested that the
gill epithelium might be damaged by the formation of
insoluble metal-protein complexes. Histological ex-
amination  of the  gills  of rainbow trout killed  in
solutions  of  zinc,  copper,  and lead  salts  at  this
laboratory  showed that the epithelial  cells became
swollen,  separated  from the  pilaster  cells of the
lamellae,  and were finally sloughed off.  A similar
observation  was  made  by  Schweiger  (1957) using
carp  as  the test fish in solutions  of heavy metals.
In other tests, Parry (in Lloyd, 1960) found no trace
of precipitated mucus on the gills  of rainbow trout
killed by zinc poisoning.

   Analysis of the  tissues  of  rainbow trout killed
by  a  solution of zinc,  containing Zn65  as a tracer,
showed that the  gill tissues  contained  the  highest
percentage  of zinc  (Lloyd, 1960), although radio-
active zinc was  found in other parts  of the body.
Saiki  and  Mori (1955) and Joyner and  Eisler  (1961)
have shown that  zinc can be absorbed into  the body
of  the  fish from  sublethal concentrations in the
water.  Schweiger  (1957),  however, took  carp killed
by  solutions of cobalt and manganese and determined
the concentrations  of these metals  in the body, then
injected healthy  carp with  either  three  times  that
amount of  cobalt or three hundred times the amount
of manganese; the  fish survived. This suggests that
the toxic action is not internal and that, at least for
some heavy metals, it is confined to the epithelial
cells  of  the gill lamellae.  Analysis of the gills of
rainbow trout killed by a  zinc solution showed  that
the concentration of metal present was only double
the normal zinc  content, so that the amount required
to kill may be quite small.
* Water Pollution Research Laboratory, Stevenage, England,

-------
182
ENVIRONMENTAL REQUIREMENTS OF FISHES AND WILDLIFE
u_
o
o
o

UJ
Q_
<
o
       4,000
       2,000
       1,000
          (a)
             Jl	END_OF EXPERIMENT (3 days)



                     A           '
        400
         200
                                         COPPER

                                         ZINC
                                  I
                       I
                                  10,000



                                   4,000


                                   2,000


                                   1,000



                                    400


                                    200


                                    100
                                                                                END OF EXPERIMENT (7 days)
                                                                 I
                                                                          I
I
I
                     1
                                                                 10
                                                                                            20
                                 2            4                     124
                                       CONCENTRATION OF METAL AS Ms/Mt
Figure 1. Relation between concentration of copper or zinc and median period of survival of rainbow trout, (a) in hard water, (b) in soft water,
        For explanation of Ms/Mj see text.
   If  the toxic action  of  heavy  metals is confined
to the gill epithelium, then the following hypothesis
can be put forward. When the rate at which the heavy
metal ions  enter  the  gill epithelial  cells is less than
the rate  at which they are removed into the blood
stream, no build-up of metal ions  will occur in the
epithelial cells, and the fish will survive. If the rate
at which the heavy metal ions enter the gill epithelium
is greater than the rate at which they are removed into
the blood stream, then a build-up will occur, and the
fish will die.  This suggests that there will be a lethal
threshold concentration of heavy metals for fish. When
this concentration is  present at the gill surface, the
rate  at which  the metal enters the gill epithelial cell
is balanced by the rate at which these ions are re-
moved  into the  blood.   Inspection of the log con-
centration-log survival time curves  for several heavy
metals indicates that  a lethal threshold concentration
probably  exists,  since  after a period of  some days
these  curves  become parallel with the survival-time
axis.

   If  the  concentrations of the heavy metals are ex-
pressed as the multiple of their lethal threshold con-
centrations, i.e.,  Ms/Mt, where  Ms is the concen-
tration of metal in solution and M£ the lethal threshold
concentration,  the log concentration-log survival time
curves for copper and zinc salts to rainbow trout are
identical, both in hard and  soft water (Figure  1),
indicating that their toxic action may be similar.  If
Schweiger's (1957)  data for  the toxicity of cadmium,
nickel, cobalt, mercury,  and manganese  to rainbow
trout  are re-plotted in this way (Figure 2), they show
that,  although the points for the first three  metals
lie on the same curve, those for mercury and man-
ganese are  different,  which  may indicate that these
two metals have a somewhat different action.
                                     10,000

                                  u.
                                  o
                                  Q
                                  o
                                  K
                                  UJ
                                  0.
                                  o
                                  LU
                                      4,000
                                       2,000
                                                           1,000
                                        400
                                                                                      X  MERCURY
                                                                                      •  MANGANESE
                                                                                      O  CADMIUM

                                                                                      A  NICKEL

                                                                                      D  COBALT
                                                           I
                                                                                           I
                                                          2           4

                                                   MULTIPLE OF 7-DAY TL,,
                                                                                                         10
                                  Figure 2.  Relation between concentration of several metals and
                                           survival  time of rainbow trout  (data  from Schweiger,
                                           1957).
                                                                                                      GPO 816-361—7

-------
                      Factors That Affect the Tolerance of Fish to Heavy Metal Poisoning
                                                                                                 183
EFFECTS OF ENVIRONMENT ON TOXICITY

   A change in  the  susceptibility of a fish to heavy-
metal poisoning  can be measured either by a difference
in survival time or by a difference in the concentration
of metal  required  to  kill the fish in a given time.
Because of  the  curvilinear shape of the log concen-
tration-log  survival time  curve,  the most useful
method is to compare concentrations of metal required
to kill  the  fish only after a  considerable exposure
time, and the optimum time is that at which the TLm
obtained is  a lethal threshold concentration.

CALCIUM CONCENTRATION

   Although many heavy metals have been shown to
be more toxic in soft water than in hard water (Jones,
1938;  Tarzwell  and Henderson, 1955;  Cairns  and
Scheier, 1957; Lloyd and Herbert, 1962), the extent of
the difference in toxicity appears to  vary for different
metals.  Some of the differences observed may have
been caused by  the decreasing solubility of the heavy
metals  as the water becomes more alkaline, but the
presence of calcium ions  in the water also reduces
the toxicity of heavy metal ions.  With rainbow trout
there is  some  evidence  (Lloyd and Herbert,  1962)
that, when the log lethal threshold  concentrations of
either   zinc,  copper,  or  lead  salts in solution  are
plotted  against  the  log total hardness of the water,
the points obtained are adequately fitted by a straight
line  (Figure 3)  from which the lethal threshold con-
  o
  i-
  ct:
  o
  0
  3
  o
  1/1
  UJ
  a:
       4.0
       2.0
       1.0
      0.40
      0.20
0.10
      0.04
      0.02
                _L
                  _L
          TO     20      40   60    100     200   320
      TOTAL HARDNESS OF THE WATER, ppm as CaC03
Figure 3. Relation between the total hardness of the water and
        the lethal threshold concentrations of  dissolved  lead,
        zinc, and copper salts for rainbow trout.
                                                   centration for any intermediate total hardness value
                                                   can be quite accurately interpolated. It is interesting
                                                   to note that the  slopes  of the lines obtained are dif-
                                                   ferent for each metal.

                                                     It  is not  known why an increase  in calcium ion
                                                   concentration reduces the  toxicity of  heavy metals,
                                                   since Jones'   (1938) conclusion that the presence of
                                                   calcium prevented the precipitation of mucus does not
                                                   hold for rainbow trout,  where no precipitated mucus
                                                   was observed.   Some experiments  made at this lab-
                                                   oratory, however, may shed some light on the problem.
                                                   Preliminary experiments on the effect  of water hard-
                                                   ness  on the toxicity of  zinc were made with rainbow
                                                   trout reared  in  hard  water, and batches were ac-
                                                   climatized to softer waters for up to  3 days.  Under
                                                   these conditions the toxicity of zinc to rainbow trout
                                                   was similar  in  both hard and soft water.  Further
                                                   experiments showed that rainbow trout reared in soft
                                                   water  were more sensitive to zinc poisoning in soft
                                                   water  than those reared in hard water and tested in
                                                   soft water.  Finally, it was found that rainbow trout
                                                   that had been  kept in hard water had to be acclimatized
                                                   to soft water for  a least  5 days before they became as
                                                   sensitive as soft-water reared rainbow  trout.  This
                                                   suggests  that the protective action  of calcium is
                                                   internal and that some  calcium has to be lost by the
                                                   hard-water reared fish before they attain soft-water
                                                   sensitivity. Some support for this suggestion is given
                                                   by  Houston  (1959)  who has  shown that  the cellular
                                                   content of calcium in the steelhead trout may increase
                                                   with the calcium content of the water.
                                                   EFFECT OF TEMPERATURE
                                                     A  decrease in temperature usually increases the
                                                   survival time of fish in toxic solutions; experiments
                                                   with rainbow  trout in solutions  of  zinc (Lloyd,  1960)
                                                   showed that the  survival times increased 2.35 times
                                                   when the temperature  was  reduced from  22 °C to
                                                   12°C.  If temperature affected only  survival time,
                                                   then the lethal threshold concentration would be un-
                                                   affected by temperature, since at this concentration
                                                   survival time curve is  parallel to the survival-time
                                                   axis. The data in Figure 4 show in fact  that this is so.
                                                                   4,000
                                                           E 2,000
                                                           E
                                                           > 1,000
                                                           o;
                                                           •=>
700

400


200-
           -END OF EXPERIMENT
                  (3 days)

                    o 13.5° C
                    x 15.5° C
                    a 18.5" C
                    A 21.5"C
                                                                  2     4    7  10     20  30
                                                                  CONCENTRATION OF ZINC, ppm

                                                   Figure 4.  Effect of temperature on  the survival of rainbow trout
                                                           in solutions of zinc.

-------
184
ENVIRONMENTAL REQUIREMENTS OF FISHES AND WILDLIFE
   A similar conclusion was reached by Cairns and
Scheier  (1957) for the toxicity of  zinc  to bluegills,
since there was little difference  in the 96-h TLW
values obtained at 18°C  and 30° C in either a hard
or a soft dilution water.

DISSOLVED-OXYGEN CONCENTRATION

   The increase in toxicity of a poison, which occurs
when the dissolved-oxygen concentration of the water
is reduced, can be expressed  by dividing the lethal
threshold concentration obtained with oxygen at the
air  saturation value (XSat) by the lethal threshold
concentration  obtained for a lower oxygen concentra-
tion (X).  The resulting fraction, Xsat/X, can then be
plotted against the oxygen concentration of the water.
It was found  (Lloyd, 1961 a) that  the ourves so ob-
tained  for  zinc, lead,  and copper salts, with use of
rainbow  trout,  were  similar in  form (Figure  5).
Futhermore,  curves obtained  for  phenol and, with
some modification,  ammonia  were  also similar to
those obtained for the heavy metals (the curve drawn
in Figure 5 takes into account the data obtained for
these two poisons).
 8
1.6


1.5


1.4





1.2


1.1


1.0
                                    A COPPER
                                    X LEAD
                                    O ZINC
         I
               I
                    _L
               _L
        30    40    50     60    70    80    90    100
  DISSOLVED OXYGEN, PERCENT OF AIR SATURATION VALUE
 Figure 5.  Relation between the factor Xsat/X for copper, lead,
         zinc and the  dissolved-oxygen content of the water.
         For explanation of Xsat/X see text.
   Since the toxic actions of the heavy metals, phenol,
 and  ammonia were different,  it appeared that the
 increase  in  toxicity was owing  to  a physiological
 response by the fish to water of low oxygen content,
 and that the most obvious response was pumping water
 more rapidly through its gills.

   The following hypothesis  has been put forward  to
 explain why this increase in respiratory flow also
 increases the  toxicity of poisons.   It is known that
 the rate at which ions and molecules reach a  surface
 where they are absorbed varies with the square root
 of the  rate of  flow of solution over the surface.  It
 is suggested  that  a lethal  threshold concentration
 represents a certain  rate at which  a poison enters
 a fish.  Thus, an increase in respiratory flow would
increase the  rate  at  which the poison reaches the
gill  surface,  and  the  concentration  of poison in
solution  would then have to be reduced  if this rate
were  to  be restored to its former level.  It can be
shown that the factor  Xsat/X, which is a measure of
the increase in  the rate at which poisons reach the
gill surface, also varies with the square root of the
respiratory flow.

   This  hypothesis is of some  importance,  since  it
implies that any environmental factor that increases
the respiratory  flow will  also  increase  the rate at
which  the  poison reaches  the gill surface, and this
may increase the susceptibility of the fish to the poison.

EFFECT OF ACTIVITY

   Experiments   at this  laboratory  have shown that
increased  swimming  speed increases the suscepti-
bility of rainbow trout to zinc poisoning (Herbert and
Shurben, in prep). This increase in susceptibility is
not very great,  and, at swimming speeds  close to the
maximum  that trout can sustain for 1 or 2 days, the
lethal  threshold concentration is only about 0.7 of the
lethal threshold  concentration obtained in  almost still
water. Parallel experiments were made to determine
the oxygen consumption of  these fish  at different
swimming  speeds, and hence to calculate  the increase
in respiratory  flow.  The results  indicate that the
observed increase in  toxicity can be  accounted for
by the increase in respiratory flow, which gives some
confirmation  to  the  hypothesis  put forward  in the
previous section.

   Schweiger  (1957) determined  the toxicity of several
heavy metals  to four  species of fish: rainbow trout,
char,  carp, and tench.  In every case  the order of
sensitivity  was  trout > char :> carp> tench,  and he
suggested that this order was  related to the difference
in activity among the species.  From data  given by
Joyner (1961) it appears that the brown bullhead is
more  resistant  to zinc poisoning than are salmonids;
it tolerated 12 ppm zinc for 14 days in water of total
hardness 74 ppm as CaCOs.  He also showed that the
rate of uptake of zinc by the brown bullhead (Joyner,
cit)  is considerably  less  than  the rate  of uptake of
zinc by salmon fingerlings (Joyner and Eisler, 1961).

      TOXICITY OF MIXTURES OF POISONS

MIXTURES OF COPPER AND ZINC

   From existing literature, reviewed by Doudoroff and
Katz  (1953), it appeared that mixtures of zinc and cop-
per  salts  were  much more toxic than would be ex-
pected from  their individual  toxicities.  Since such
synergism  required placing on a quantitative basis,
further experiments on  the toxicities of mixtures of
these  two  metals  were  made at this  laboratory
(Lloyd, 1961 b).

   It  has  been   shown in  Figure  1  that  the log con-
centration-log survival  time  curves for copper and
zinc salts  in  both hard  and soft waters are identical
when the concentrations of heavy metal are expressed
as  MS/M^. If the combined toxic action  of these two
metals in  a  mixture were additive,  then a similar

-------
                         Factors That Affect the Tolerance of Fish to Heavy Metal Poisoning
                                                                             185
curve should be obtained if the concentration of the
metals is expressed  as Cus/Cut +  Zns/Znt.  Tests
were  made with mixtures of zinc and copper salts in
a  hard  water  (320 ppm as CaCOs) where Cut = 1-1
ppm, Znt = 3.5 ppm, and the ratio Cus/Cut: Zns/Zntwas
 1:2; and  in  a soft water  (15 to 20 ppm as CaCOs)
where Cut = 0.044 ppm, Znt = °-56 ppm, and the ratio
Cus/Cut:Zns/Znt was 2:1.  The results  are  compared
in Figure 6 with the curves obtained  for the  individual
metals.  It can be seen that  a lethal threshold con-
centration of the mixture in both dilution  waters is
obtained  when the value of  Cus/Cut  + Zns/Znt is
equal to unity, but for high concentrations of the mix-
ture in  soft water, survival times were considerably
shorter than would be expected, indicating thatsyner-
gism occurs under these conditions.  When predicting
a  safe concentration  of a mixture of copper and zinc
salts  for  rainbow  trout, however, it may be assumed
that the combined action of the two metals is additive.
                              TOXICITY  OF  EFFLUENTS  CONTAINING  HEAVY
                              METALS

                                 Experiments have  been made at  this  laboratory
                              to determine whether the toxicity of actual effluents
                              to  rainbow  trout  could  be  predicted  from their
                              chemical analysis.  In one series of tests,  Herbert
                              (1962) showed  that the toxicity of spent still liquors
                              from gas  and coke works could be predicted from
                              their contents  of ammonia and monohydric phenols.
                              More  recently, work has been extended to sewage
                              effluents,  which  often  contain  heavy  metals and
                              ammonia as well  as a great variety  of other toxic
                              substances.   Sewage  effluents  were  obtained from
                              several  sewage  disposal  works receiving different
                              proportions  and types  of trade wastes,  and their
                              toxicities  were  measured  under  standard  con-
                              ditions  (temperature  10° C, pH 7.8 to 8.0, dissolved
                              oxygen 50 percent of the air saturation value).  From
                     4,000 -
- -I- -r - - END OF EXPERIMENT
              (3 days)
                   J 2,000
                   <
                     1,000
                   a
                   LU
                      400
                      200
                                       I
                                              J_
10,000


 4,000

 2,000

 1,000


  400

  200

  100
                                                                   END OF EXPERIMENT
                                                                         (7 days)
                                                             I
                                                                J_
                                                   X
                                                J	I
                                                                               X X
                              1       2        4              1   2    4     10   20
                                CONCENTRATION OF METAL AS (Cns/Cnt + Zns/Znt)

    Figure 6. Toxicity of mixtures of copper and zinc sulphate to rainbow trout, (a) in hard water, (b) in soft water. Continuous curves
            drawn from Figure 1 (a and b).
MIXTURES OF  HEAVY METALS WITH OTHER POI-
SONS

   Since both copper and zinc exert their toxic effect
in a similar way, it is not  surprising that the com-
bined effect of low concentrations is additive. These
metals  may, however, occur in an effluent together
with other poisons whose toxic action may be different.
It has recently been shown at this laboratory (Herbert,
1961) that a lethal threshold concentration of a mixture
of ammonia and zinc salts for rainbow trout is ob-
tained when the value  of As/At + Zns/Znt becomes
unity.    The same  method can be used to calculate
the  lethal threshold  concentration of a  mixture of
ammonia and phenol (Herbert, 1962).  It is possible,
therefore, that the lethal threshold  concentration of
other pairs of poisons, and also of mixtures  contain-
ing more than two poisons, might be  obtained when
the  sum of the proportion of  the individual lethal
threshold concentrations becomes unity.
                               these tests the 3-day Toxicity Index of the effluents
                               was  obtained;  this Index is the number of times the
                               effluent has to be diluted to obtain a 3-day TLm.  At
                               the  same time, the  concentrations of the individual
                               heavy  metals  ammonia,  phenol,  and  cyanide were
                               determined.  From laboratory data on the toxicity of
                               each  of  these  poisons, their individual 3-day TLW
                               values for the test conditions were calculated; the
                               concentration  of  each poison  found in the effluent
                               was  expressed as the  proportion of  this expected
                               3-day  TLm,  and  these  values were  then summed
                               to give a predicted Toxicity Index. In Figure 7 the
                               relation is shown between the observed and predicted
                               Toxicity Indices for all  12 tests.  In two tests there
                               was  no mortality in the undiluted effluent  (Toxicity
                               Indices < 1), and these were predicted to be nontoxic;
                               in another test there was a 20 percent mortality in
                               the  undiluted  effluent where  the predicted Toxicity
                               Index was 0.9.   In the  remaining nine tests there
                               was  good agreement between the predicted and ob-

-------
186
                      ENVIRONMENTAL REQUIREMENTS OF FISHES AND WILDLIFE
        100
      o
      2
         10
      x
      o
      <
      a
        1.0
       u
        0.1
                     1.0         10         100
              OBSERVED 3-DAY TOXICITY INDEX
Figure 7. Comparison between  predicted and observed 3-day
        Toxicity Indices for several sewage effluents.  Figures
        in parentheses  are percentages of rainbow trout killed
        in undiluted sewage effluent.
served  Toxicity Indices over a wide  range of toxic-
ities.
   These results are of considerable value, since they
indicate not only that  the  Toxicity Indices of these
effluents  may  be   predicted  from their  chemical
analyses, but also that the relative importance of each
toxic constituent of the effluent  may be assessed.
With  the  sewage  effluents used  in these tests,  the
contribution of the heavy metals  (chiefly copper  and
zinc) ranged  from  13  to 77 percent  of the total
toxicity. It is also probable that adequate predictions
could be made of the Toxicity Indices of these sewage
effluents in dilution waters of different chemical  and
physical characteristics.

DISCUSSION
   The  ultimate aim of laboratory bio-assays is to
enable  one to predict a concentration of poison or
effluent that must not be exceeded in a river if fisher-
ies are to remain unharmed. It has long been realized
that concentrations found  to  be  safe under  strictly
controlled  laboratory  conditions cannot be used un-
altered for these predictions, and that an application
factor is  required to take into  account  the  effects
various components of the environment have on the
toxicity of the  poison, together  with a  margin of
safety. It is becoming clear that  the true application
factor required will be different for different poisons
and for different rivers, and any  one  standard factor
may well be too high in some circumstances and too
low in others.   The work described in this paper re-
presents an attempt to place  on  a quantitative basis
some  of the effects that  the  chemical and physical
nature of the  water have  on the toxicity of the heavy
metals to  fish,  so that a more accurate estimation of
the application factor can be made.
   It  is  fully realized  that these  experiments  go
only a little way towards a solution of the problem,
since the  chemical  and physical nature of a river
never  remains  constant but fluctuates,  and more
field  work  is required  to  correlate the results ob-
tained from laboratory investigations with those found
in practice.  Moreover, the measurement of toxicity
used has been the lethal threshold concentration, since
this value  can be accurately determined,  but more
information  is required about  sublethal effects that
may result in a gradual deterioration of the condition
of the fish.  Nevertheless, it is only by a more com-
plete understanding of the basic mechanisms involved
in  the relation between the susceptibility of fish to
poisons and changes in the evironment that any real
advance can be made.
               ACKNOWLEDGMENT
   This  paper  is published by permission of the
Department  of Scientific and  Industrial  Research,
Great Britain.
                                              REFERENCES
Cairns,  J.  and A.  Scheier.    1957.   The effects of
temperature and hardness of water upon the toxicity of
zinc to the common bluegill (Lepomis macrochirus
Raf.).    Notul. nat. Acad.  Philad. No.  299,  1-12.

Doudoroff, P. and M. Katz.  1953.  Critical review of
the literature on the toxicity of industrial wastes and
their components  to fish.  II. The  metals, as salts.
Sewage industr. Wastes, 25:  802-839.

Herbert, D. W. M.  1961.  Freshwater fisheries and
pollution control.   Proc. Soc.  Wat. Treatment Exam,
10:  135-161.

Herbert,  D. W.  M.   1962.   The toxicity to rainbow
trout of spent  still liquors from the distillation of coal.
Ann. appl. Biol., in the press.

Herbert, D. W. M.  and D.S. Shurben.  In preparation.
Houston, A.  H.  1959. Osmoregulatory adaptation of
steelhead trout (Salmo gairdnerii  Richardson) to sea
water. Can. J. Zool., 37:  729-748.
Jones, J. R. E.   1938.  The relative toxicity of salts
of lead,  zinc and copper to the stickleback (Gaster-
osteus aculeatus L.) and the effect of calcium on the
toxicity  of lead and zinc salts. J. exp. Biol.,  4: 394-
407.
Joyner,  T.   1961.   Exchange  of  zinc with environ-
mental  solutions by the brown  bullhead.   Trans.
Amer. Fish. Soc., 90: 444-448.


Joyner,  T.  and  R. Eisler.   1961.   Reteation and
translocation of radioactive zinc  by  salmon  finger-
lings.  Growth, 25:  151-156.

-------
                       Salinity Requirements of the Fish, Cyprinodon macularius
                                               187
Lloyd, R. 1969.  The toxicity of zinc sulphate to rain-
bow trout.  Ann. appl. Biol., 48: 84-94.
Lloyd, R.  1961  a.   Effect of dissolved oxygen con-
centrations on the toxicity of several poisons to rain-
bow  trout  (Salmo gairdnerii   Richardson).   J. exp.
Biol., 38: 447-455.
Lloyd, R.  1961  b.   The toxicity of mixtures of zinc
and copper sulphates to rainbow trout (Salmo gaird-
nerii   Richardson).   Ann. appl. Biol., 49:  535-538.

Lloyd, R. and D. W. M. Herbert.  1962. The effect of
the environment  on the toxicity of poisons to fish. J.
Inst. Pub. Hlth Eng., in the press.
Saiki, M. and T. Mori.  1955. Studies on the distri-
bution of administered radioactive zinc in the tissues
of fish.  I. Bull. Jap. Soc. sci.  Fish., 21:  945-949.

Schweiger, G. 1957. Die toxikologische Einwirking von
Schwermetallsalzen auf  Fische und  Fischnahrtiere.
Arch. Fischereiwissenschaft, 8: 54-78.
Tarzwell, C. M. and C. Henderson. 1955. The toxicity
of some of the less common metals to fishes. Seminar
on San. Eng. Asp. at U. S. Div. of Reac Dev. and Pub.
Hlth Ser., Washington, 286-289.
                  SALINITY REQUIREMENTS OF THE FISH, CYPRINODON MACULARIUS

                                                Otto Kinne t
   The basic prerequisites for a sound analysis of the
environmental requirements of an organism are (1)
long-term  rearing and breeding  experiments under
adequate, ecological conditions in the laboratory, and
(2) parallel investigations in the fie^d.  It may be
useful to assess the environmental requirements of a
given  group of  aquatic life as a whole.  More im-
portant for  understanding of the dynamics of an eco-
system and for  proper  evaluation of water quality
criteria, however,  are the requirements of the basic
units of the system,  i.e., its populations or species.
And within each population or species we must know
the environmental  requirements of the  different life
cycle  stages of  individuals,  such as egg, larva, and
adult, and of the two sexes.

   The first step in the  analysis of environmental
requirements  is the establishment of quantitative and
qualitative relationships between the organism and its
environment.  One  of the principal difficulties we en-
counter  here  is a consequence  of two well-known
facts:    (1)  that   an  organism  reacts to its total
environment rather than  to  single factors, and (2)
that the total environment has to be broken down into
single factors in order to facilitate measurement as
well as assessment of specific effects and of critical
factor intensities.  Since it is impossible to measure
simultaneously all  physical, chemical and biological
properties of a  natural  environment as a  whole, a
compromise is the  only answer - a compromise aim-
ing  at a restriction to factors assumed to be  most
effective.

   Such restriction, however, has often been carried
too  far  and numerous papers  have been published
dealing with one environmental factor only.  A mono-
factorial analysis is dangerous.  It  may easily lead
to wrong conclusions, and should be replaced wherever
possible by  a bi-,  tri- or poly-factorial approach.

   Let me exemplify these statements by presenting
some of our results concerning the effects of salinity
on basic life processes in the euryhaline and eury-
thermal desert pupfish Cyprinodon macularius Baird
and  Girard.   These results demonstrate that other
environmental  factors,  i.e., temperature,  and the
amount of ambient dissolved oxygen,  are capable  of
considerably  modifying or  masking  the effects  of
salinity.   I shall restrict myself here to  some ex-
periments on growth and food conversion in fry and
maturing fish, and on rates of embryonic development
in eggs.  The experiments were conducted under the
widely different salinity conditions  under which this
species is able  to  exist and reproduce in nature and
laboratory.  All fish were born and raised under the
given conditions.

GROWTH AND FOOD CONVERSION

   Growth and food conversion were studied in fresh-
water and in 15°/oo,35°/oo and 55°/oo (±0.6°/oo)salinity at
various constant temperatures, which were maintained
within ± 0.6°C for a 14-hour day and in practically
air saturated water  (details in Kinne 1960).

   The growth curves obtained in the four salinities and
at a constant temperature of  30° Care shown in Figure
1.  At 30°C,  growth rates decrease in the following
order :35°/oo, 15°/oo, 55°/oo, freshwater. This order is
subject to considerable change in different tempera-
tures.  A comparison between fish raised in fresh-
water and others raised in 35°/oo salinity (Figure 2)
shows that at the lower temperature levels, 15° and
 * Professor Meyer-Waarden to his 60th birthday.

 t Biologische Anstalt Helgoland, Hamburg-Altona, Germany.

-------
188
ENVIRONMENTAL REQUIREMENTS OF  FISHES AND WILDLIFE
                      o
                      z
                      LL>
                      O
                        5.5
                                  20
                                       40
                                              60
                                                   80
                                                         100    120
                                                                     140
                                                    • 12;
                                                    •I	;
                                       116 !   i
                                       II  I  i ;
20
                                                                           FRESHWATER -
.  160  .days
'•   :  24 weeks
; I  :  i;   ; i
  Figure 1. Growth rates of Cypnnodon macularius reared in four different salinities at 30°C.  Semilogarithmic plot.  Each value represents
          the average total length of 12 individuals. Horizontal: age in days and weeks. All fish were raised under the given conditions
          (From Kinne 1960).
      26

      24

      22

      20

    I 18


    O   ""
    5 18
                                            ofr
                                                         20
                                 o
                                 1U
                                 <  12
                                 O


                                    11
          15       20      25       30
                    TEMPERATURE, °C
                                            35
Figure 2.  Effects of temperature on the salinity curve of growth.
         Each circle represents the average total length of 12
         individuals at ages of 6, 12,  and  24 weeks, respec-
         tively. All fish were raised under the given conditions
         (From Kinne 1960).

20 °C, growth is faster in freshwater,  but at the higher
levels, 25°, 30° and 35 °C, it is faster in 35%o. The
combined  effects of salinity and temperature are il-
lustrated diagrammatically in Figure  3; the tempera-
ture  curve of  growth  established for fish born and
raised in  15°/oo salinity  rotates  clockwise in  lower
salinities,  but  counterclockwise  in higher salinities,
the curves intercept at approximately 25 °C.
   Food conversion — i.e., increase in dry weight of
fish,  divided by dry weight of  white worms eaten,
                                                                                    £ 35%
                                                                                      15%
                              FRESH- '.
                              WATER
                                                                         20         25          30
                                                                              TEMPERATURE, °C
                                                                                   35
                                      Figure 3.  The effect of various combinations of salinity and tem-
                                               perature  on  total  length  in  12-week-old Cyprinodon
                                               macularius raised under the  given conditions.   Semi-
                                               logarithmic plot.  (From Kinne 1960).

                                      times  100— is, at 30°C, most  efficient  in 15°/oo,
                                      followed by  35°/oo, and  then freshwater  (Figure 4).
                                      Conversion efficiency, too, depends on temperature,
                                      as shown in Figure 5.  In 35 /oo salinity, food con-
                                      version  is  most efficient at 20°C,  followed by  15°,
                                      25°, 30°,  35°C.   At  30°C,  and especially at 35°C,
                                      the fish defecated at a tremendous rate; at 35°C,
                                      they produced whitish feces, representing worms that
                                      had passed the intestinal  tract  almost untouched by
                                      digestive processes.   The  efficiency  of food con-
                                      version  depends also  on other factors, especially on
                                      food supply  and age (Kinne 1960).  At 30°C and under
                                      restricted food supply conditions,  the average effi-
                                      ciency  over a period of 16  weeks was found to be
                                      14.4 in 15°/oo,  10.6 in 35°/oo, and 8.8.  in freshwater;

-------
                           Salinity Requirements of the  Fish, Cyprinodon macularius
                                                    189
                      -  20
                         10
                                   8-10
                                                    12-14             16-18
                                               WEEKS AFTER HATCHING
 Figure 4.  Efficiency of food conversion in Cyprinodon macularius raised in three different salinity levels at 30°C. Semi logarithmic plot.
          Each value represents the average conversion efficiency per fish per 2 weeks and is based on 12 individuals kept under con-
          ditions of restricted food supply. (From Kinne 1960).
corresponding values obtained under conditions of un-
restricted food supply were  1.3 in 35°/oo and 0.9 in
freshwater.   (Except for these data, all efficiencies
quoted refer  to results obtained  under  conditions of
restricted food supply;  details  in Kinne 1960).  Con-
version  becomes  significantly  less  efficient with
increasing age.
hours after spawning and incubated in five different
salinities:  1/2 freshwater  (one part  glass distilled
water plus one part tap water), 35°/oo, 45°/oo,  55°/oo
and 70°/oo  (details in Kinne  and Kinne  1962).  Under
these conditions, the  criteria  used to  determine the
rate of embryonic  development  were the  length of
time  between  fertilization  and  hatching,  and  the
in
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8-10 12-14 16-18
WEEKS AFTER HATCHING
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         raised  at five different temperature levels in  35°/oo
         salinity.  Semilogarithmic plot.  Each value represents
         the average conversion efficiency per fish per 2 weeks
         and is based on 12 individuals kept under conditions
         of restricted food supply.  (From Kinne I960).

EMBRYONIC DEVELOPMENT

   Eggs were  laid and fertilized in a salinity of 35 ±
2°/oo at water temperatures between 26° and 28°C,and
in practically air-saturated water (14-hour day). They
were  transferred into  incubators approximately 4
                                                                    20
                                                                                                       32
                                                                                                                   36
                  24          28
                     TEMPERATURE, °C
Figure 6.  Incubation periods in days as function of salinity and
         temperature  in eggs of Cyprinodon macularius.   Semi-
         logarithmic plot; handfitted curves; individual data for
         45°/oo and 55°/oo omitted.  Average data from  10 to
         15 eggs in each case.  Salinities remained practically
         constant  in  1/2  freshwater, they varied up to  2°/oo
         between 35°/oo and 45°/oo, and up to 3.5°/oo between
         45%>o  and  70°/oo.  Water temperatures were  main-
         tained within ± 0.2°C up to 30oC and within £ Q.l<>c
         between 30°C and 36°C.  (From Kinne and Kinne 1962).

-------
190
ENVIRONMENTAL REQUIREMENTS OF FISHES AND WILDLIFE
criminate between effects on the development proper
and on  the process of  hatching.  In most cases, the
two methods produced similar results.

   Figure  6  shows in a  semilogarithmic plot the
incubation periods for  eggs incubated in the 5 differ-
ent  salinities  at  various  constant temperatures
between 19°C and  36°C and  at oxygen  levels equiv-
alent  to  100  ±  5  percent air saturation.  It reveals
a progressive retardation of  developmental rate with
increasing salinity.  This retardation is significant-
ly affected by  temperature; the differences in the
five salinity  levels are progressively augmented as
the temperature increases.   Towards higher tem-
peratures, the curves  show inflections indicating the
position of the respective upper critical temperatures
(in 55°/oo no data were available above 31.8°C). The
inflections occur approximately: in  1/2 freshwater at
35°C, in  350/00  at  34°C, in  45°/oo at 33.3°C,and in
70°/oo  at  31.8°C.    The upper lethal  temperature of
incubation (100%   mortality),  too,  is a function of
salinity; in 1/2 freshwater and in 35°/oo it lies near
36°C, in 45°/oonear34.2°C,andin 70°/oo near 32.5°C.

   These  effects  of salinity on rates of embryonic
development,  and  on  the upper  critical and  lethal
temperatures are  statistically highly significant and
easily  reproducible. Nevertheless, a further analy-
sis discloses that  it is  not  the  salinity  per se that
causes these effects but the concomitant change in the
level  of  saturation for  ambient dissolved  oxygen.
Figure  7  shows that the  saturation values of oxygen
from  normal dry  atmosphere in water of different
salinities vary from 6.7 milliliters of oxygen per liter
(1/2 freshwater at 19°C) to 3.2 milliliters of oxygen per
liter (70°/oo at 36°C). This represents a total reduction
of 52 percent.
                                       A series of experiments conducted at oxygen levels
                                    equivalent  to  70 ± 10 percent  air  saturation and to
                                    300 ± 80 percent air saturation demonstrated the im-
                                    portance of the  amount  of  oxygen available to the
                                    embryo (details in Kinne and Kinne 1962).
                                       A comparison between values obtained in 70 per-
                                    cent air-saturated water and  in  100 percent  air-
                                    saturated water  (Figure 8), reveals that development
                                    proceeds at similar rates up to a temperature of 15°
                                    to  18°C; at higher temperatures, the incubation period
                                    becomes increasingly longer in water of 70 percent
                                    air saturation.  In 35°/oo  and 27.5°C, incubation per-
                                    iods are about 25 percent longer than under conditions
                                    of  100 percent air saturation.  The upper lethal tem-
                                    perature of incubation drops  in 1/2  freshwater to
                                    approximately  28°C  and  in  35°/oo  to  approximately
                                    27.5°C.

                                       In 300 percent air-saturated water, development is
                                    significantly accelerated in 35°/oo and 70°/oo (Table 1).
                                    At  32 °C development is  accelerated  12 percent in
                                    35°/oo and 27percentin70°/oo, relative to the respec-
                                    tive results obtained in water of 100 percent air sat-
                                    uration.  There is practically no acceleration in 1/2
                                    freshwater.  At 34°C, incubation periods are shorter
                                    in  35°/oo than  in  1/2 freshwater at 100 percent air
                                    saturation, and rates  are  almost the same in 70°/oo
                                    salinity as  1/2  freshwater  at  100 percent air sat-
                                    uration.  The upper  lethal temperature of incubation
                                    shifts upward,  and lies,  for example, in 70°/oo at
                                    approximately 34.5 °C (it lies near 32.5 °C in 100 per-
                                    cent air saturation).  These and other results in-
                                    dicate  that  the retardation  effect  observed in high
                                    salinities can  be nullified largely or  completely by
                                    a  rise  in  the  amount of  dissolved oxygen.  In fact,
                                    salinity per se, that  is,  salinity as osmotic stress,
                                    seems to exert little influence.
                                               OXYGEN, ml/I
  Figure 7.  Saturation values of oxygen (ml/I) from normal dry atmosphere at 760 mm, for salt concentrations ranging from glass-distilled
          water to 85°/oo salinity at eight different temperatures. (From Kinne and Kinne 1962).

-------
                       Salinity Requirements of the Fish, Cyprinodon macularius
                                                                                                       191
                       20
                     r 10
                    CO
                    3
                    oS
300%
Air saturation
4.0
3.8
3.5
lethal
   *Approximate saturation, giving the amount of dissolved oxygen present as percentage of the air saturation
    value at a given temperature and salinity and an atmospheric pressure of approximately 760 mm.
   Comparable effects  of reduced levels of dissolved
oxygen  on  embryonic development in  fishes  have
been reported by a number of authors.  Johansen and
Krogh  (1914) were among the first biologists to ex-
pose developing  fish embryos to different levels of
dissolved oxygen.  They reported that levels below
50 percent air saturation cause delay in the develop-
ment of plaice incubated at 6° to 7°C.  Similar re-
tarding effects have since been described for a variety
of fish species by Stockard  (1921), Lindroth (1942,
1946), Einsele (1956), Seymour (1956,1959), Alderdice
et al.  (1958),  and Gar side  (1959, 1960).  Lindroth
(1942,  1946)  working on the  Atlantic salmon, Salmo
solar, and the pike,  Esox Lucius, found that the re-
tarding  effects of reduced levels of dissolved oxygen
increase at higher temperatures, and the same re-
                                                       lation was  later  reported by Garside in Salvelinus
                                                       namaycush  (in 1959), Salvelinus fontinalis, and Salmo
                                                       gairdneri  (in  1960).    Our  results on  Cyprinodon
                                                       macularius are in full agreement with these findings.

                                                          Growth,  food conversion,  and embryonic develop-
                                                       ment are basic life processes. In Cyprinodon macul-
                                                       arius  they  are significantly affected  by  salinity.   I
                                                       hope  I have demonstrated that the specific effects of
                                                       salinity  on  these  life  processes  and the  salinity re-
                                                       quirements of  this fish are intimately correlated to
                                                       other  environmental factors, and that the importance
                                                       of the salinity factor as part of the total environment
                                                       of Cyprinodon macularius can only be fully appreciated
                                                       and  understood  within  the  framework  of  a com-
                                                       prehensive, poly-factorial analysis.

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192
ENVIRONMENTAL REQUIREMENTS OF FISHES AND WILDLIFE
                                            REFERENCES
Alderdice, D. F., Wickett, W. P. and Brett, J. R. 1958.
Some effects of temporary exposure  to low dissolved
oxygen levels  on Pacific  salmon eggs. J.  Fisheries
Research Board Can. 15, 229-249.

Einsele,  W.   1956.   Untersuchungen uber die At-
mungsphysiologie sich entwickelnder  Salmonideneier;
ihre Anwendung auf die Natur und auf die zuchterische
Technik. Osterr. Fischerei 9, 2-18.

Garside, E.  T.   1959.   Some effects of oxygen in
relation to temperature on the development of Lake
Trout embryos.  Can.J.Zool. 37, 689-698.
	  1960.  Some aspects of the developmental rate
and meristic numbers in salmonids.  PhJD. Thesis,
Univ. Toronto.

Johansen, A. C. and Krogh, A. 1914. The influence
of temperature and certain other factors upon the rate
of development of the  eggs of fishes.  Conseil per-
manent intern, exploration mer, Publ. de Cir Constance,
68, 1-44.

Kinne, O.  1960.  Growth, food intake, and food con-
version in a  euryplastic  fish exposed  to different
temperatures and  salinities.  Physiol.Zool. 33, 288-
317.
                                  Kinne, O. and Kinne, E. M.  1962.  Rates of develop-
                                  ment in embryos  of  a cyprinodont fish exposed to
                                  different temperature-salinity-oxygen combinations.
                                  Can.J.Zool. 40, 231-253.


                                  Lindroth, A.  1942. Sauerstoffverbrauch der Fische.
                                  n.  Verschiedene Entwicklungs- und Altersjstadien vom
                                  Lachs und Hecht.  Z.vergleich.Physiol. 29, 583-594.

                                  	   1946.    Zur  Biologie  der Befruchtung  und
                                  Entwicklung  beim Hecht.   Mitteilungen  Anstalt f.
                                  Binnenfischerei bei Drottnigholm, Stockholm.


                                  Seymour, A. H.   1956.  Effects of temperature upon
                                  young chinook salmon. PluD.Thesis, Univ.Washington.


                                  	1959. Effects of temperature upon the formation
                                  of vertebrae and  fin  rays in young Chinook salmon.
                                  Trans.Am. Fish.Soc. 88, 58-69.

                                  Stockard,   C.  R.   1921.   Developmental rate and
                                  structural expression:  an experimental study of twins,
                                   "double  monsters" and single  deformities, and the
                                  interaction  among embryonic  organs  during their
                                  origin and  development.   Am.J.Anat.  28, 115-277.
                                             DISCUSSION
DISSOLVED OXYGEN REQUIREMENTS OF  FISHES

Q, Do  differences in  size of fish at hatching persist
   if the sac fry are  maintained under the conditions
   of reduced oxygen?

A, Some of our early results indicated  that  size
   differences  do persist after  hatching  but  later
   experiments  indicated that the differences may be
   small.

Q. Do  water velocities of  6 centimeters per hour
   over the eggs have a different effect from a velocity
   of zero?

A. We  haven't  tried  zero so I cannot answer your
   question except to say that  any increase  above 3
   centimeters per hour produced an effect.

Q. In the swimming experiments, are the fish  able
   to swim in low dissolved oxygen simply because
   they are incurring an oxygen debt?  When we
   discuss  the  avoidance  response of  fish  to low
   dissolved oxygen,  we  must  be careful to avoid
   teleological explanations.

A, We  measure  the sustained  swimming speed and
   within limits this  speed is not affected by the
                                      interval of time between water velocity increases.
                                      Therefore,  this is probably a test of fatigue and
                                      not of the ability to incur  an oxygen debt.  Early
                                      work  was  done  with apparatus that could not
                                      exhaust fish  rapidly  because the water velocity
                                      could  not be increased enough. In that work, fish
                                      swam   as  long as 48 hours before  exhaustion.
                                      This indicates failure is not due to sudden stress
                                      and, therefore,  not due  to an oxygen  debt.  In
                                      regard to your comment about teleological expla-
                                      nations, you are correct, but our data do indicate
                                      a directed response and not just random movements.

                                  Q.  Is  the variation in  dissolved oxygen  found in
                                      natural waters the reason that growth is less
                                      there  than  under more uniform laboratory  con-
                                      ditions?

                                  A.  Fluctuations in dissolved oxygen have been shown
                                      to be  detrimental to  growth; growth is similar
                                      to growth that would be  obtained at a  constant
                                      dissolved oxygen level equal to the lowest of the
                                      fluctuating concentrations.

                                      Comment - This lesser growth may also be due
                                      to the  inaccessibility  of food.  For example, we
                                      took smallmouth bass from a stream and planted
                                      them in a pond and the pond population grew better.

-------
                       Salinity Requirements of the Fish, Cyprinodon macularius
                                             193
   Comment - The Ohio River Sanitation Commission
   standards  for  dissolved  oxygen  stipulate  that
   dissolved oxygen shall not  go below 5 ppm for
   periods exceeding 8 hours  and never below 3 ppm.
   These times are not rigid or exact and the concen-
   trations  are tentative.   We feel that  tentative
   criteria  are necessary,  however, until better
   information is available.

   Comment - At the time these standards were set
   they seemed to provide adequate safety, but they
   are  hard to  enforce and it now appears that a
   single minimum concentration  might be better.

    THE ENVIRONMENTAL REQUIREMENTS OF
   CENTRARCHIDS WITH SPECIAL REFERENCE
   TO LARGEMOUTH BASS, SMALLMOUTH BASS,
              AND SPOTTED BASS

Q. Is an increase in weight of  150 or 170 percent in
   15 days an unusual growth rate for bass 80 to 90
   mm long?

A. I think  such  an  increase  is accomplished in the
   natural  habitat.  We consider a growth to one-half
   pound in 3 months not unusual.
    WATER QUALITY CRITERIA FOR FISH LIFE

Q. Is 5 ppm dissolved oxygen a maximum  or an
   average  concentration  desirable  for salmonid
   waters  or  is  it  a  concentration necessary  at a
   certain time of day?

A. Lower  concentrations can be accepted locally and
   temporarily.

Q. Is the  level  of  5 ppm dissolved  oxygen based
   on tolerance or some other consideration?

A. It is based on normal growth and development.
TOXICITY  OF SOME HERBICIDES, INSECTICIDES,
            AND INDUSTRIAL WASTES

Q. In the experiments with sodium chloride,was there
   a relationship between size and length of the fish
   and  susceptibility?   Some workers  have found
   a closer relationship to size  than to species of
   salmonids.

A. We used only  one size of fish.
Q. What type of water was used in these experiments?
   I would  expect different  and variable  results
   depending on the hardness of the water.

A. This work was done in a hard rather alkaline water.
   Comment - This may explain the high tolerance you
   found.

Q. In long-term  tests with sodium chloride, did the
   fish shed their scales?

A. I think so.
THE  TAINTING OF FISH BY OUTBOARD MOTOR
EXHAUST WASTES AS RELATED  TO GAS AND OIL
                 CONSUMPTION

Q. Could the outbreak of Columnaris have been affected
   by pollution;  in this case, outboard motor exhaust
   wastes?

A. This possibility did not occur to us.

Q. Did panel members know when they were getting
   fish from a contaminated pond?

A. The  members did not know what type of fish they
   were tasting.

Q. What would be the effects of circulation and size
   of the body of water ?

A. This lake was stratified with athermoclineat!5 to
   20 feet.

Q. What about  the  levels  of lead in the water?

A. Lead was less than 10 micrograms per liter, which
   is the lowest level we could detect.

   Comment  - The 96-hour TLW for outboard motor
   wastes was reached at a fuel consumption of 1 gallon
   per 1900 gallons of water.

Q. How  long  do  fuels remain in suspension and what
   would usage of these lakes in previous years have
   on present levels?

A. Evidence from carbon column extracts indicated
   the carryover from  previous years was  below
   detectable levels and persistence would be a matter
   of weeks.
EFFECTS  OF  OIL  POLLUTION ON MIGRATORY
                     BIRDS

Q, Do  you know  of  any references to oil pollution
   on the Great Lakes themselves ?

A. One study was made on the Great Lakes and they
   were found to be generally clean.  There have not
   been many  studies made on the loss of wildlife
   due to oil pollution.
FACTORS WHICH AFFECT THE TOLERANCE OF FISH
          TO HEAVY METAL POISONING

Q. Would  someone venture  an  opinion as to whether
   the antagonistic effect of calcium on the toxicity
   of heavy metals might be due to a loose combination
   of calcium ion with the mucous protein thereby
   making such binding sites unavailable to the metal
   ion?

A. (Hiltibran, 111. Nat. Hist. Survey) In our laboratory
   we investigated the effect of several divalent metal
   ions on  the  oxidative phosphorylation systems
   of bluegill liver mitochondria, and found that zinc,

-------
194
                       ENVIRONMENTAL REQUIREMENTS OF FISHES AND WILDLIFE
   cadmium,  calcium,  and manganese  ions  inhibit
   oxygen uptake. But when we investigated the ade-
   nosine triphosphatase systems of mitochondria, we
   found most enzyme  activity  in the  presence of
   zinc and cadmium ions.  Calcium and manganese
   ions were less effective.  Magnesium enhances
   oxygen uptake; it  gave about  the  same order or
   magnitude  of  results  in  the  adenosine triphos-
   phatase systems as  did calcium and  manganese.
   The two enzyme  systems  I have mentioned  are
   part  of  the  over-all  oxidative phosphorylating
   sequence of enzymes by which energy is produced
   and converted into usable  compounds; however,
   in one part of the sequence zinc, cadmium, calcium,
   and manganese ions were inhibitory, but in another
   part of the over-all system they promoted enzyme
   activity.  Thus it would appear that there is a very
   delicate balance of metal ions within cells, and if
   the concentration of  some ion is  increased, then
   this metal ion could alter some part of the physi-
   ological  processes.   If this  inhibition  becomes
   severe, death  might result.

      In  the case of the effects of metals on protein,
   I believe the factors you may be observing are the
   various gross physiological responses, which are
   based  or  controlled by  underlying  biochemical
   processes.    When   these  latter  processes  are
   altered or inhibited then all other additional
   physiological processes that  are based upon the
   underlying chemical reactions also stop and the
   fish dies.  For example, if energy production is
   blocked at some point and energy production ceases,
   then all physiological responses requiring energy
   also stop.   Many other systems may be affected
   in a similar manner.

      We have  conducted some  experiments to  de-
   termine  the  competition between  metal ions on
   oxygen uptake. We found that magnesium ions can
   overcome  the inhibition  of  oxygen  uptake  by
   manganese ions, but magnesium ions apparently do
   not alter the effect of manganese ions  on  the
   phosphorylating reactions.  We have not pursued
   this area of research to any extent.

      We have not investigated the effect of  copper
   ions  so  I  cannot make any comment as to their
   effect.

      Calcium is an oxidative phosphorylation  un-
   coupler;  that  is,  it  interferes with the transfer
   of energy from oxidation of substrates to organic
   phosphate  compounds.   In  the  bluegill liver
   mitochondria  systems  calcium does  not  appear
   to  act as  an oxidative phosphorylation  uncoupler
   due to inhibition of  oxygen uptake.   Usually un-
   couplers do  not inhibit oxygen uptake.

      Many divalent metal ions in vitro are protein
   precipitants.   It is  possible that relatively high
   concentrations  of metal ions within cells  might
   cause some  disarrangements of the proteins of the
   cell,  which  also  could  cause  loss  of  function.


      In another session there was some mention of
   selenium,  both  as a toxic principle and  in its
   physiological role.  I would like to mention that
   vitamin Bi2, an important physiological compound,
   contains  a  cobalt ion and  a cyano group as part
   of  its structure; this is another case where the
   physiological   compound   contains  elements  or
   groups that  under other conditions  might be ex-
   tremely toxic.

      Thus we  are concerned with a very complex
   situation,  which is going to require  much work to
   unravel.

Q. Would the effects of two toxicants with dissimilar
   modes of  action be additive, for example, arsenic
   and copper?


A. I cannot say except to point out that zinc and am-
   monia  are  additive although  the mode  of  action
   is  different.


Q. Have you noted a difference in gill histology among
   fish  maintained  in  water  with  different calcium
   contents?  We  have noticed that fish kept in hard
   water have  more mucus on the  gills, which could
   suggest the  role of calcium.

A. I have not noticed a difference, but I have not  really
   looked for one.
     SALINITY REQUIREMENTS OF THE FISH
            CYPRINODON MACULARIUS

Q. Is there a difference in activity in the two extremes
   of salinity?


A. We   found  that temperature,  but  not  salinity,
   produced significant differences in activity.

-------
    THE CONCENTRATION OF RADIONUCLIDES IN AQUATIC ORGANISMS, THEIR

            PASSAGE THROUGH THE FOOD CHAIN, AND  POSSIBLE EFFECTS

                                        Conrad P. Straub*, Chairman


     RADIOACTIVITY IN  FRESHWATER ORGANISMS OF SOME LAKES OF NORTHERN ITALY t

                                             Oscar Ravera %
   The purpose  of this  study was to compare the
 existing radioactivity (natural radioactivity plus fall-
 out) in the various levels  of the lacustrine food-chain.

   The lakes investigated during  the  last 2  years
 (1960-1961) are presented in Figure 1. Figure 2 shows
 the collection zones of Lake Maggiore,  where most
 of this research was carried out.  Three charac-
 teristic  cross-sections   of the lake are also given:
 A-A' for  the northern basin,  which has a maximum
 depth of 372 meters;  B-B1,  for the basin controlled
 by the Toce  River; and C-C', for  the southern basin,
 both of which have a maximum depth of 100 meters.
   Total beta activity was measured with an  equip-
 ment for anticoincidence counting  with two Geiger-
 Muller tubes  with a 1" window.   A  100-channel
 scintillation  apparatus was used for gamma spectrom-
 etry.  Mean values of total beta activity calculated
 for the material collected in the three basins of Lake
 Maggiore are listed in Table 1.

   The radioactivity of plankton and fishes was studied
 by A. Berg and the data on this subject listed in Table
1  are  reported in  Chapter Vn of the Final Report
of IAEA Contract No. 59 (1961).

   The  radioactivity  of phytoplankton was higher
than that of zooplankton. This is probably due to the
higher  ratio  of surface to  volume  in  algal  cells
as  compared  with zooplankton.   The radioactivity
of the whole body  of  fish was  influenced very little
by  season  or  zone  of  collection whereas it  was
greatly affected  by the age  of the fish.  Slight dif-
ferences  in  radioactivity  were  noted  among the
three species studied (Coregonus  sp., Alburnus al-
borella, De Fil. and Lota lota, L.); these differences
are probably the result of differences in diet.


   Benthos collected in different zones, seasons, and
depths had a total  beta  activity of about 1 picocurie
per gram wet weight.

   No  significant  differences were noted for sedi-
ments  collected in different basins but at the same
depth.
                             Figure 1.  Lakes from which the samples have been collected:
                                     L. Maggiore, L. Alserio, L. Pusiano, L. Commabbio,
                                     L. Annone and L. Varese.
* Chief,Radiological Health Research Activities, Robert A. Taft Sanitary Engineering Center.

•)• A great part of this work was carried out for the IAEA Contract No. 59 (1961): Berg, A., Margaret Merlini, 0. Ravera and V. Tonolli
  Accumulation  of Fission Products from Fall-out in Lake Biota (Logo Maggiore).

J Biologia, EURATOM, Ispra, Italy.
                                                   195

-------
196
THE CONCENTRATION OF RADIONUCLIDES IN AQUATIC ORGANISMS
                          1 CICOGNOLA
                          2 ISPRA
                          3 FONDOTOCE
                          4 ANGERA
                          5 MONVALLINA
                          6 ARONA
                          7 IS S.GIOVANNI
                          B FERIOLO

                          • COLLECTION STATION
                                              A  N  D
                            Figure 2.  Loke Moggiore-stotions where the samples were collected.
                 Table 1.  MEAN TOTAL BETA ACTIVITY IN SAMPLES OF FRESHWATER
                                  ORGANISMS FROM LAKE MAGGIORE
Sample
zoo-
Plankton
phyto-
Coregonus
Fishes Alburnus
Lota
Larger aquatic plants
Periphyton
Benthos
Sediments
Shell
Viviparus
Soft tissues
Molluscs
Shell
Unio
Soft tissues
Mean values (pc/g wet wt.) of the total beta activity
Northern basin
1.0
1.2
2.5
2.2
	
1.0
25.7
	
Toce River basin
__-
1.4
2.2
8.4
1.2
	
5.6
1.2
Southern basin
1.0
1.2
2.3
1.6
1.6
1.2
1.7
26.9
3.6
1.1
2.0
2.8

-------
                  Radioactivity in Freshwater Organisms of some Lakes of Northern Italy
                                               197
   As  far  as the larger  aquatic  plants  are  con-
cerned  individuals of  the  same species,  e.g. La-
garosiphon, growing  in different places had different
values of radioactivity. Interspecific differences were
found within the  same zone.  The beta- and gamma-
activity  of  periphyton was  higher than that  of its
substrate (Figure 3).

   The  Molluscs  are very  important organisms in
the littoral  biocoenosis  because of their biomass
and their wide distribution.  Lymnaea peregra,  L.,
and Physa acuta  (Gastropoda, Pulmonata),  Viviparus
ater,  Cris.  and Jan (Gastropoda, Prosobranchia) and
Unio mancus var. elongatulus (Lamellibranchia) were
the species studied,  but a great part of  the work was
carried out  on the latter two species.

   The  data in  Table 1  show that the  radioactivity
calculated for the soft tissues of Unto was higher
than that measured for the shell, whereas in Viviparus
the radioactivity of the shell was higher than that of
the soft tissues; also, Viviparus shell showed a higher
radioactivity than Unio shell.

Samples were collected from seven stations to evaluate
the radioactivity differences  in  the shell and  in the
soft tissues in Viviparus  of either sex dwelling in
different zones.  Each sample,  composed of at least
100 individuals collected at random, was representa-
tive of the  whole population in  a zone.  The data in
Table 2  lead to  the following conclusions: 1)  an in-
 Table 2.  TOTAL BETA ACTIVITY (pc/g wet wt.)
  OF VIVIPARUS ATER COLLECTED IN SEVEN
         STATIONS OF LAKE MAGGIORE

StaHrm

Cicognola
Ispra
Fondotoce
Angera
Monvallina
Arona
Is. S. Giovanni
Total beta activity
Shell
Male
1.2
2.8
3.5
3.7
3.9
4.6
9.6
Female
3.6
3.0
3.5
5.6
4.4
3.5
5.7
Soft tissues
Male
0.6
1.0
1.0
1.1
1.5
1.6
2.0
Female
0.6
0.7
0.8
1.0
1.3
1.6
1.4
crease in the radioactivity of the  shell corresponds
to an increase in radioactivity of the soft tissues, 2)
great differences of shell radioactivity appear between
stations and between sexes, and 3) small differences
in radioactivity of the soft tissues are observed be-
tween populations.

   Because the concentration  of  strontium-90 in the
shell of Viviparus differed very little among populations
and between sexes, the total radioactivity of the shell
can be explained only in part by its strontium-90 con-
tent (Table  3); it is  therefore necessary to assume
the presence of one or more beta emitters not yet
                                         Total  beta-activity    (pc/g w.w.)
Station
Fenolo
Is. S. Giovanni
Cicognola
Ispra
Lagarosyphon
2.15
1,94
1,59
1,42
Periphyton
8,37
3,83
6,40
6,24
                pc
                 80--
                 60-
                 40
                 20--
                  O-1-
                           LAGAROSYPHON
                                                                       Plant
                                                                       Periphyton
                                                                     VALLISNERIA
                         Figure 3.  Concentration of the radionuclides in the aquatic plants and periphyton.

-------
198
                  THE CONCENTRATION OF RADIONUCLIDES IN AQUATIC ORGANISMS
identified.   These  beta emitters probably  are not
present in the  shell of Unio except in traces because
in  this  material  the  strontium-90  concentration
reached  a value slightly lower than that of the total
beta activity.

   The  higher  level of radioactivity reached in the
soft tissues of Unio (in comparison with that  of the
soft tissues  of Viviparus)  was probably due to the
fact that the tissues of Unio always contained a certain
amount of manganese-54,  whereas this  radionuclide
was never found in  Viviparus (Figure 4). Using the
same method, we were unable to detect manganese-54
in lake  water,  fishes,  aquatic  plants, or sediment
(Ravera and Vido, 1961), which indicates  that the con-
centration of this  radionuclide  in  these materials
was lower than the sensitivity of the instruments used.

   The importance  of the role played by age on the
concentration of  strontium-90   and  manganese-54
in Unio was  evaluated.   Figure  5 clearly shows the
relation between the manganese-54 and strontium-90
contents and the age of the organism.  The concentra-
    Table 3.  STRONTIUM-90 CONCENTRATION IN
   SHELLS OF VIVIPARUS ATER COLLECTED IN
      DIFFERENT ZONES OF LAKE MAGGIORE
Station
Ispra
Monvallina
Is. S. Giovanni
Arona
Sr90 in Shell (pc/g wet wt.)
Male
1.3
1.4
1.7
1.9
Female
1.6
1.5
1.7
1.6
tion  of  strontium-90 decreased with increasing age,
whereas the opposite was true for  manganese-54.
This different pattern may be explained by the following
facts: 1) Unio may live mdre than 10 years, (Pelseneer,
1935);   2) the metabolic rate of the shell is very slow
in comparison with that of the soft tissues;  3) stron-
tium-90  and  manganese-54  are  artificial radio-
nuclides that have  diffused  in  the biosphere only in
recent years.
   Therefore, the  oldest  individuals  secreted the
greater part of  their shell in an environment without
radiostrontium,  whereas the youngest ones secreted
all, or  a  great part, of their shell when the lake was
contaminated by  this radionuclide.  The higher con-
centration of manganese-54 in the oldest individuals
is presumed to  be due to the accumulation of this
nuclide  in the body of Unio during its life-span.  Be-
cause the samples of Unio  collected at four stations
were very large it seemed improbable that the age
of the molluscs could be considered responsible for
the different manganese-54  content calculated for the
various populations. Therefore this pattern is probably
due to the different manganese concentrations at the
four stations (Table 4).
   The  data in Table 5 show the differences in radio-
activity among  different parts of the body of Unio
and Viviparus.
   Because the sediment, which plays a very important
role in  the  nutrients turnover of a lake,  had a very
high radioactivity,  it seemed interesting to compare
the values  for  the sediments collected at different
depths.    Figure 6  shows that the  mean total beta
activity increases with depth, from less than 1 meter to
50 meters,  whereas from  50 meters  to 360 meters
it remains  constant at 31 picocuries per gram wet
                       1000 ••
                                                                 VIVIPARUS  ATER
                       1000 +
                                                                  UNIO MANCUS
                                                                               1.0
                      Figure 4. Gamma spectra of the shell and soft parts of Viviparus after and Unio Mancus.

-------
                   Radioactivity in Freshwater Organisms of some Lakes of Northern Italy
                                              199
weight.   The total beta activity of benthonic  organ-
isms, as noted before, did not vary greatly at different
depths.  These two facts lead to the foil owing supposi-
tion:  1) at different depths there are similar concen-
trations for the radionuclides utilized by the benthonic
organisms and very different concentrations  at dif-
ferent depth for those radionuclides discarded by the
benthos;   2) the benthonic organisms cannot take up
radioactive material after a certain  level of radio-
activity is reached.

   The  natural  radioactivity  has  been increased in
recent years  by addition of fallout.   It seemed in-
teresting to ascertain if such an increase was detect-
able in  the depth of the sediment,  A core was col-
lected from  the  sediment, therefore,  at a depth of
313 meters (January, 1961) and subdivided into suc-
cessive layers  of  three  millimeters  of  thickness.
The   curve, drawn from the data obtained,  shows
clearly  a  peak  of  about 15 millimeters, perhaps
   Table 4. CONCENTRATION OF MANGANESE-54
    AND STRONTIUM-90 IN UNIO MANCUS AND
     VIVIPARVS ATER COLLECTED IN FOUR
         STATIONS OF LAKE MAGGIORE
           n° individuals
          400-

Station

Ispra
Fondotoce
Arona
Angera
(pc/g wet wt.) (pc/g wet wt.)
Soft tissues
Unio
0.11
0.25
0.30
0.40
Viviparus
0
0
0
0
Shell Unio and
Viviparus
1.6
1.6
1.6
1.6
corresponding  to the high values calculated for the
fallout of 1959 (Figure 6).  The natural radioactivity
values were those below a depth of 24 millimeters and
were confirmed by other similar values obtained at
greater depth inside  the same core.  The spectrum
in Figure 7 shows the gamma emitters present in the
surface  layer  of  the sediment collected at a depth
of 5  meters.

   Data  on other  lakes of  Northern Italy (Varese,
Commabbio, Alserio,  Pusiano, Annone and Garda) led
to very  similar conclusions even  though it became
evident that each basin has its own characteristics for
radioactivity  as well as  for  any  other ecological
factor.   For  instance, the total beta activity  of the
           pc/g w.w.
           2-
             1-0,2
                                                                     1-0,1
                                                                                         (SHELLS)
                       50
                                  lotT
Figure 5. Distribution curve of fhe individuals of Unio collected
        in the different classes of length (age). Influence  of
        the age on the concentration of Sr90 in the shell and of
        Mn54 jn the soft tissues.

shallow  sediments varied from a  maximum of  7,6
picocuries per gram wet weight for Lake Commabbio to
a minimum of 2.7 picocuries per gram wet weight for
Lake Maggiore; on the other  hand, all values for the
shallow sediments were lower in relation to those of
deeper sediments in the same  lake.

               ACKNOWLEDGMENTS

   Thanks are due to Dr. Margaret Merlini (Biology,
EURATOM, Ispra) for her revision of the English test.

   The  author is  grateful to  Prof.  Ph.  Bourdeau
(Biology, EURATOM, Ispra) for his suggestions and the
revision of the manuscript,  to Prof. V.  Tonolli (I
stituto  Italiano di Idrobiologia,  Pallanza) and to  Dr.
K. Gerbaulet  (Biology, EURATOM,  Ispra) for their
suggestions.

   The author expresses sincere thanks to the Health
Physics Group, EURATOM, Ispra for its assistance
in the  measurements of radioactivity and for useful
discussion.
                   Table 5.  TOTAL BETA ACTIVITY IN DIFFERENT PARTS OF UNIO AND
                           VIVIPARUS, AND MANGANESE-54 ACTIVITY FOR UNIO
Sample
Shell
Visceral sac
Mantle
Gills
Hepatopancreas
Operculum
Unio mancus
Total beta activity
1.99
2.01
2.69
3.77
Mn54
0.00
0.00
0.19
0.50
Viviparus ater
Total beta activity
6.74
1.91
1.73
2.10

-------
200
THE CONCENTRATION OF RADIONUCLIDES IN AQUATIC ORGANISMS

                                              SURFACE OF THE SEDIMENT
                                                                         Figure 6.  Total Beta-activity of the sediment of
                                                                                  Lake Maggiore at different depths and
                                                                                  in different layers of a core.
                                               10   20   30   40
4400.
4200
4000.
3800 J
3600.

3400.
3200.
3000.
2800.
2600.
2400.
2200.
2000.
1800.
1600.
1400.
1200.
1000.
800.
600.
400.
200.
Ce"«
1
is/channel
.1
8 1
' H
iii

1
.



•








                                                                                Energy  (MeV)
                                                   0.5                      1.0

                                Figure 7. Gamma spectrum of the superficial layer of the sediment.

-------
                   Radioactivity in Freshwater Organisms of Some Fishes of Northern Italy
                                              201
                    SUMMARY

   Samples of plankton, larger aquatic  plants, fishes,
benthos,  molluscs, and sediment collected in some
lakes of Northern Italy  (Maggiore, Garda, Alserio,
Pusiano,  Commabbio, Annone, and Varese)were  ex-
amined to compare their radioactivity.  Noteworthy
was  the presence  of  manganese-54,  an activation
gamma emitter, in the soft tissues of Lamellibranchs.
The  concentration of this  radionuclide  was  very
different in populations settled in different zones of
Lake  Maggiore.   The highest level of radioactivity
was found  in the sediment; in this material total beta
activity increased with increasing depth.  The peri-
phyton always showed higher  values of radioactivity
than the aquatic plants on which it lives.  Season and
zone had a  very small influence on absorption of radio-
activity by plankton,  fish,  and benthos; whereas age
of the organisms played a very important role on this
process both in molluscs and in fishes.
                                            REFERENCES

                          Berg, A., Margaret Merlini, O, RaveraandV. Tonolli,
                          1961.  Accumulation of  Fission Products from Fall-
                          out in Lake  Biota (Lago Maggiore).   Final Report-
                          IAEA Contract No. 59.

                          Pelseneer, P., 1935  - Essai d'ethologie zoologique
                          d'apres I'etude des Mollusques.  Acad. Roy. Belgique,
                          Bruxelles.

                          Ravera,  O.  e  L. Vido,  1961 - Misura del  Mn54 in
                          popolazioni di  Unio pictorum, L. (Molluschi, Lamel-
                          libranchi) del Lago Maggiore. Mem. 1st. Ital. IdrobioL,
                          13:75-84.

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 202
                      THE CONCENTRATION OF RADIONUCLIDES IN AQUATIC ORGANISMS
                       ACCUMULATION OF RADIONUCLIDES AND THE EFFECTS

                                     OF RADIATION ON MOLLUSCS

                                              Thomas J. Price *
   Molluscan shellfish  are among the most economi-
cally important organisms inhabiting estuarine waters.
These  animals feed by removing suspended particles
from large volumes of water filtered through their
gills.  This filtered material includes phytoplankton,
protozoa, bacteria, non-living detritus,  and suspended
inorganic particles.   Most material  is  removed  in
particles entrapped in the mucous net of the gills; these
mucoid particles  are then transported along ciliary
tracts to the labial  palps where they are either ingested
or  rejected as  pseudofeces.   These mechanisms  of
filtering, transporting, and  sorting   are complex.

   The principal food of molluscan shellfish is phyto-
plankton.  These  single-cell  algae, because of their
vast numbers and small size, present large surfaces
for the direct adsorption of elements and  their radio-
nuclides (Goldberg, 1952; Rice, 1953; Rice and Willis,
1959).    Since many molluscs are  both filter feeders
and bottom dwellers, phytoplankton with its associated
elements and their isotopes is available  as food both
when alive in suspension and after death as settling
estuarine detritus. It is known that phytoplankton will
concentrate certain nuclides (Rice, 1953, 1956;  Chip-
man, Rice,  Price, 1958); thus shellfish  may become
exposed to  an  amount of radioactivity  over that  of
the surrounding medium when feeding on radioactive
plankton.  Molluscan  shellfish  can obtain nutritive
elements and their radioisotopes either from ingested
food or  from the  surrounding water.  Shellfish, by
accumulating radioactivity, also  may become an im-
portant link in the passing of radioactivity to higher
trophic levels.

   Estuaries in which a great many of the economically
important molluscs are found have become potential
areas of radioactive pollution. These bodies of water
are collecting basins for drainage from the surround-
ing land masses.  Pollutants reach estuaries either by
leaching from the surrounding soil or in water from
contaminated rivers.   Within the past 15 years, the
number  of  reactors and  other  possible sources  of
accidental release of  radioisotopes  into estuarine
waters  has increased.   Many radioactive isotopes
have become important because of their release  in
effluents from  the various types  of reactors.  The
increased number of licensed isotope users has created
a problem of disposing  of radioactive wastes. Already
there are a number of  nuclear ships adding to radio-
active wastes released into marine waters.  A large
percentage of the  increased  radioactive  fallout from
nuclear detonations might possibly find its way into the
oceans.   Therefore,  it is  important that information
be  obtained so that the biological cycling of radioactive
materials can be followed.

   Radioactive isotopes have a common characteristic
in that  they emit  ionizing rays and particles that are
damaging to living  plants  and animals.  Radiation
occurs both from radioactive materials in the water
and nuclides ingested by the aquatic organism. Selec-
tive  accumulation of  activity  in  certain tissues of
organisms may  result in localized damage.  Harmful
effects to the biota may be classified as somatic or
genetic  according to whether the  effect damages the
immediate physiological functions or tissues  of the
animal or involves  the reproductive processes  thus
resulting in abnormalities in subsequent generations.
   The accumulation of radioactive materials and the
effects of radiation  on marine organisms are  of im-
portance since they  can affect man.  There is a possi-
bility that radioactive contaminants may reach man in
high concentrations  through seafood.   Also, there is
concern  that the abundance of these marine organisms
may be  diminished from changes  brought  about by
radiation injury.
   The  following  is a report of  experimental work
carried  out at the Radiobiological Laboratory of the
Bureau  of Commercial Fisheries, Beaufort, North
Carolina, a cooperative project of the U. S.  Fish and
Wildlife  Service and the Atomic Energy Commission.

   The author wishes to  express his appreciation to
Dr. A. A. Armstrong, School of Textiles, North Caro-
lina State College,  Raleigh, North Carolina, for  per-
mission  to use their cobalt-60 source.
   The  accumulation  and retention of cesium-137,
cerium-144,  zinc-65,  and  gold-199 and the effects
of radiation were followed on the hard clam, Mercen-
aria  mercenaria,   Linne;  the  oyster,   Crassostrea
virginica, Gmelin; and the bay scallop, Aequipecten
irradians, Say.   These animals were collected in the
vicinity  of the Radiobiological Laboratory and held in
tanks of running sea water until used.   All fouling
organisms were cleaned from the  shells prior to using
the animals in experiments.
   Cotton-filtered sea water having a  salinity range
from 29 to 35°/oo and a temperature of 22 ±2°C was  used
in all uptake experiments.  The sea water for retention
experiments was pumped directly from a source out-
side the laboratory; salinity and  temperature  varied
with the  tide and seasons.

   Live  animals were wrapped in  polyethylene and
measured for their  contained radioactivity.   Animal
tissues   were  prepared for counting by  rinsing  in
filtered sea water to remove loosely adsorbed surface
activity.   All radioactivity measurements were made
with a  well-type  scintillation crystal  attached  to a
conventional sealer.   Size of the crystal used was
determined by size  of  the animal.  Radioactivity  is
reported as counts  per minute per gram with appro-
priate  corrections  for  geometry,  background,  and
decay.
 * U. S. Bureau of Commercial Fisheries, Beaufort, North Carolina.

-------
                                  The Effects of Radiation on Molluscs
                                               203
    Radionuclides may be  grouped  into two general
 classifications based on their origin.  One  includes
 fission  products resulting from the splitting  of the
 nucleus of the uranium atom or plutonium atom; the
 others  are  induced radionuclides formed by  stable
 isotopes capturing neutrons.  The radionuclides that
 occur from the fissioning of uranium are known, but
 induced radionuclides vary since they are isotopes of
 elements present in the area of the neutron flux.  Some
 of these induced radionuclides have been found to be
 more important  than  the  fission products  as con-
 taminants in radioactive wastes.  Two of the fission
 products of  concern in  the  oceans are cesium-137
 and cerium-144.  Zinc-65, which was found in marine
 fishes soon after the 1954 nuclear detonations in the
 Pacific, and  gold-199 are two induced radionuclides
 that are discussed in this paper.

    The rate of accumulation, levels of concentration,
 mode of entry, and  assimilation of specific elements
 depend largely on their physical and chemical states
 in  the  medium and the  physiological  demands  of
 organisms for the element. Elements and their radio-
 isotopes are  present in sea water either as particles
 or as ions.   A radioisotope occuring in sea water in
 a  particulate  form  may become  associated with a
 molluscan shellfish by adsorption to its body surfaces
 or by ingestion into its digestive tract.  Only a  small
 quantity  of the particulate nuclides may be retained as
 they  pass  through the digestive tract, since particles
 do not  readily penetrate  through semi-permeable
 membranes;  however,  the  ionic  radionuclides have
 little difficulty passing through tissue membranes and
 thus  have  the potential of being assimilated to higher
 levels.
                    CESIUM-137

   Cesium is one of the alkali metals and is chemically
 similar to sodium, potassium, and rubidium (Hood and
 Comar,  1953).  The  radioisotope cesium-137 with a
 physical half-life of 30 ±3 years is found in sea water
  500
  3000
  2500]
as
O
at
ui
  2000
  1500
O 1000
   500
                     OYSTERS
         '•	•«••
   WATER
	V	-CT	
                           6
                          DAYS
                                          10
                                                 12
             Figure 1.  Uptake of Csl37 by oysters.
          Figure 2.  Uptake of Csl37 by hard clams.

as a fission product chiefly in the ionic state.  Cesium-
137  is accumulated to relatively high levels by soft
tissues of shellfish, thus making it an important radio-
active contaminant since these soft parts are used as
food by man.
   Carrier-free cesium-137 was used as cesium chlo-
ride and  was in  secular  equilibrium with its radio-
active daughter product,  barium-137.  The time be-
tween sampling and measurement of activity was long
enough for  secular equilibrium to occur between the
parent-daughter  components,  thus  eliminating  the
effect of  biological separation in the determination.
The  amount of cesium-137 that was  accumulated or
the concentration factor of this nuclide in the tissues
of the animals was computed by dividing the activity
per gram of animal or tissue by the activity per gram
of sea water in which the animals were held.
   The uptake of cesium-137 by oysters and clams is
shown in  Figures 1 and 2, respectively. Clams accu-
mulated the  radioisotope  more than oysters.  At the
end of 20  days, the soft parts of the clams concentrated
cesium-137 by a factor of  six over the  cesium-137
concentration in sea water. The clams were continuing
the uptake  of  the  isotope  at  the termination of the
experiment,  so it was not possible to determine the
final concentration factor for  clams.  At the end of
12 days, the concentration factor of cesium-137 in the
soft  parts of the oysters was  five;  however, at that
time the tissues of the oysters appeared to be entering
into a steady state condition with the isotope.
   It  is necessary to determine the time required for
biological  elimination  of  the  nuclides by  molluscs,
should they become polluted by radioactivity.  This
is essential to know  so the  shellfish will again be
safe  to  use as food.   The time required for a living
tissue or organ or an individual to eliminate one-half
of a  given amount of substance through  biological
processes is  referred  to as the biological half-life.
As an example, if a mollusc contains 1000 counts per

-------
 204
                    THE CONCENTRATION OF RADIONUCLIDES IN AQUATIC ORGANISMS
 1000
o
uj
a.
 '100
                    8
10   12   14   16   18  20  22  24
    DAYS
             Figure 3. Loss of Csl37 by oysters.
 minute initially and in 3 days the counts decrease to
 500  counts  per minute,  this  decrease  of  activity
 would give  a biological half-life of 3 days  for this
 particular animal and radionuclide.

     Investigations were  carried out to determine the
 loss  of  cesium-137 by oysters and clams (Figures
 100
02
O
Ul
Q.
•s.
DC
at
\-
o
u
  10
   0   2   4   6  8   10  12  14  16  18  20  22  24  26  28
                           DAYS
             Figure 4. Loss of Cs'37 by (,ar(j clams.
                                                           O
                                                           u.
                                                           •z.
                                                           •S.
                                                           oj
                                                           O
                                                               60
                                                               50
                                       40
                                                               30
                                                               20
                                                               10
                                                                    I
                                                              O	SOFT PARTS LESS
                                                                   ADDUCTOR MUSCLE
                                                              •	ADDUCTOR MUSCLE
                                                                     1
                                                                                        5
                                                                                      DAYS
                                                                                                      8
                                                                                                               10
                                             Figure 5. Uptake of Csl37 by bay scallops.
                                    3  and  4).   The soft tissues of  oysters lost activity
                                    rapidly  during the  first 18 days,  at  which time the
                                    rate of loss decreased.  After 25 days, only 4 percent
                                    of the total activity remained in the tissues.  The loss
                                    of cesium-137 in clams was followed for 28 days.  As
                                                              1000
                                                            o
                                                            at
                                    •s.
                                    sx.
                                    UJ
                                    a.
                                                            •z.
                                                            o
                                                            u
                                                               100
                                                                10
                                              O — SOFT PARTS LESS ADDUCTOR  \
                                                  MUSCLE
                                              •—ADDUCTOR MUSCLE
                                               24    6    8   10   12   14   16   18   20
                                                               DAYS
                                              Figure 6. Loss of Csl37 by bay scallops.

-------
                                 The Effects of Radiation on Molluscs
                                                                                                     205
with the oysters, a  slower  rate  of  loss occurred
following the rapid initial loss. Twelve percent of the
isotope remained in the clams after 28 days, which
was  higher  than for the oysters  after the  same time
interval.   This residual activity  remaining in the
tissues of the clams and oysters was possibly the
result  of the nuclide becoming complexed in chemical
compounds within the  tissues.

   Accumulation and  loss of cesium-137 was inter-
preted as having been influenced by muscle and the
remaining soft parts.  Separate analyses of these two
components  were made of  the  uptake and loss of
cesium-137  by the bay scallop. The adductor muscle
o f the scallop is the  only portion used dietetically in
this  country. It is important to know the rates of uptake
and  loss of  cesium-137 by this tissue.  Radionuclides
entered the tissues rapidly at first, with the final level
being  higher  than that of clams  (Figure  5). There
was  a more  rapid uptake by the soft tissues other than
muscle, but in time the highest concentrations were
reached by the muscle.  The concentration  of cesium-
137  in the muscle tissue after 10 days was 10 times
that  in sea water and steadily increased, while that in
the visceral mass was concentrated 8 times and leveled
off.   It  is  apparent  that muscle is the higher con-
centrator of the nuclide.

   The visceral mass of the scallop lost cesium-137
faster  than  the adductor muscle (Figure 6). After 20
days, 25 percent of the activity remained in the muscle
while only 8 percent  remained in the visceral mass.
The  biological half-life of cesium-137 in the muscle
was  13 days and in the  visceral mass 3 days.  It is
noted that the line illustrating the  loss of  activity by
the muscle  is a regression line of anti-logarithms of
the counts.

   The different rates of uptake andloss of cesium-137
by the  muscle tissue and visceral mass of the scallop
indicate how these two components influence uptake and
loss of this nuclide in an organism. This relationship
is a rapid initial  uptake or loss as influenced by the
visceral mass, and then a longer continuous uptake or
loss as  influenced by the muscle tissue.

                    CERIUM-144

   The  physical  state  of  a fission  product in sea
water controls  to a great extent  its mode of entry
and  subsequent assimilation  by marine  organisms.
Greendale and Ballou  (1954) determined the physical
states  of fission  product  elements in  sea water by
simulating an  underwater bomb detonation.   They
found for cerium-144 that approximately 2 percent was
ionic, 4 percent collodial, and 94 percent particulate.
This large  amount of cerium-144 in sea water in
particles influences availability of this radioisotope to
molluscan  shellfish,  as evidenced in  the following
experiments.
   The concentration of cerium-144 by tissues of clams
and  oysters  was  determined  when the nuclide  was
available to the animals as particles in the medium
or  associated  with known populations of Nitzschia
closterium cells.   Cells from 1 liter of culture  were
fed daily to the animals.  To maintain optimum volume
of water to animal ratios as clams and oysters  were
removed for sampling, both the cell populations and
the volume of medium containing the cells to be fed
the  animals were decreased proportionally.   The
uptake   of the radionuclide was slow and continuous
through the  tenth  day,  after  which it fluctuated in
the tissues for the remaining 12 days of the experi-
ment.   The clams reached their maximum levels of
accumulation after 20 days, with 23 percent of that
made available daily being accumulated. It is assumed
that the remainder of the cerium-144 available during
the experiment adsorbed to the  shells of the clams
and oysters and to the container,  as water samples
taken before changing the medium each day did not
contain  any significant amounts of cerium-144.
                 o:
                 O
                 at
                 at
                 ul
                 a.
                 O
                 u
                     48000
                     36000
                     24000
                     12000
                                                             10
                                                                    12
                                                                                   16
                                                       DAYS
                                 Figure 7. Uptake of cerium-144 from water by clams.

-------
 206
                  THE CONCENTRATION OF RADIONUGLIDES IN AQUATIC ORGANISMS
   In experiments on  the uptake of cerium-144 by
clams, the animals were not sacrificed but were peri-
odically  removed  from the  radioactive  water long
enough for the activity in the entire animal to be meas-
ured. This method of repeatedly determining activity in
the same animal throughout an experiment decreases
effects  of individual variations.   Initially uptake of
the radionuclide was rapid, but began to decrease on
the third  day (Figure  7).  This  diminished rate of
uptake was undoubtedly caused by a decrease in the
availability of  cerium-144 in the water.   Only 11
percent of the original activity remained in the water
after 3 days  and  upon termination of the experiment
after 12  days only 4 percent remained  in solution.
This  removal of  the nuclide from solution  affected
the availability  of the isotope to  the  clams, and
thus possibly  influenced the levels to which cerium-
144 was accumulated.

   Investigations were  carried out to determine cer-
ium-144  uptake and distribution by shell, liquor, and
meats of  the  clams.  Animals were removed period-
ically, dissected,  and the activity in the  three com-
ponents was  determined.   Shells contained the high-
est level of  activity, followed by meats, and liquor
(Figure 8).   Radioactivity of the shell  was largely
surface  adsorption  of  cerium-144, while  activity
associated with the meats was  possibly the effects
of particles adhering  to tissue surfaces and present
in organs and structures connected with the digestive
tract.  Only  a small percentage  may be assimilated
since particle  size would be a  limiting factor  in
their absorption  through the  walls  of the intestinal
tract.

   It  is essential  to know  the time required for bio-
logical elimination of radioactive pollutants by mol-
luscs to conclude when they  again will be available
as food for man.   To  understand the metabolic role
of cerium-144 more  fully, the following experiments
were  conducted with special  emphasis on long term
retention  and whole animal counting.  To determine
                                                Of
                                                o
                                                Of
                                                111
                                                0.
                                                z
                                                S
                                                at
                                                O
                                                o
                                                     60000
                                                     48000
                                                     36000
                                                     24000
                                                     12000
                                                                                 SHELLS
                                                                   O
                                                            o/
                                                                               MEATS
                                                                — -cr	"O"
                                                                              LIQUOR
                                                                             O
                                                                             6
                                                                            DAYS
                                                                                           10
                                                                                                  12
                                                    Figure 8. Uptake of cerium-144 by component parts of clams.
                                                 the  rate  of  loss by clams, they were immersed in
                                                 cotton-filtered sea water  containing cerium-144 and
                                                 after a  suitable  time were transferred  to tanks of
                                                 rapidly flowing sea water.  The initial loss of cerium-
                                                 144  was rapid during the  first 45  days,  after which
                                                 the  loss  was reduced (Figure 9).  Cerium-144 re-
                                                 maining  after 195 days represented 20 percent of the
                                                 original  activity in  the  animals.   It is possible that
                                                 activity remaining at this time is either complexedby
                                                 the metabolic processes of the animals  or securely
                                                 adsorbed to body surfaces.
       n
       UJ
       Of
       >-
<
I-
       111
       Q.
          100
           80
           60
           40
           20
                     20
                              40
                                       60
                                               80
                                                100

                                                DAYS
                                                                120
                                                                         140
                                                                                  160
                                                                                          180
                                                                                                  200
                                     Figure 9. Loss of Ce^4 by the hard clam.

-------
                                  The Effects of Radiation on Molluscs
                                               207
   The  rate  of loss of cerium-144 by the bay scallop
was observed for 35 days. The animals were removed
from sea  water and separated into shell, visceral
mass, and adductor  muscle.   The loss of the radio-
nuclide  in all three tissues was rapid in the beginning,
followed by a reduction in the rate of loss (Figure 10).
After 35 days, the shells had lost 55 percent of the
original activity; muscle, 62 percent; and the visceral
mass, 89 percent. It appeared that any further loss of
activity from these three components would be small.
                           SHELL
                          •-•o	
                          MUSCLE
                          VISCERAL MASS
                 10
                       15     20
                          DAYS
                                    25
                                           30
                                                 35
  Figure 10. Loss of Cel44 by components of the bay scallop.

                        ZESTC-65
   In  the past most data on uptake, accumulation, and
loss of radionuclides by marine organisms has con-
cerned  single  species  held in confined volumes  of
water.   This is  not a very satisfactory manner of
determining the relationship that would exist between
the  radioactivity of the water and that of the organism
in nature, since the  volume of water per organism
would be  a controlling  factor of the experiment.  If
five animals  are placed in ten liters of water and
remove a large amount of the activity, they will have
a higher concentration factor than would have occurred
if ten animals had been placed in the same volume of
water.  Thus, sufficient volumes of water should be
used to minimize the effects of animals drastically
reducing activity  in it.   Results of our tank experi-
ments reveal  not only the effects of contamination on
an entire community,  but also permit evaluation of an
individual in relation to the ecosystem.  By increasing
the volume of water in an experiment, it is possible
to  conduct experiments  of long duration due to the
improved  physiological condition  of  the organisms;
thus both  chronic and acute contamination  can be
investigated.
   The universal occurrence of zinc in all living matter
and  its role as an essential  nutrient for plants and
animals  is firmly established  (Vallee, 1959).  The
presence  of zinc-65  in marine organisms from the
Pacific  Ocean  following nuclear test detonations has
been reported by Seymour et al., 1957; Lowman,  Pal-
umbo,  and  South,  1957;  and  Welander, 1957.   This
neutron-induced radionuclide  is  produced by nuclear
changes  of  the stable element and  occurs in marine
waters  principally in the ionic  state.  Zinc-65 can
also be introduced into the oceans as part of corrosion
products  present in the  coolant  water of  nuclear
reactors.
   Molluscs in general have a higher zinc content
than other  invertebrate  groups (Vinogradov, 1953).
Thus, these shellfish  are important as transfer organ-
isms of zinc-65 through food webs to man.  The uptake
and accumulation of zinc-65 by oysters and clams was
followed in an experimental environment consisting of
1200 liters of  cotton-filtered sea water continuously
circulated  in a fiberglass tank.  Enough carrier-free
zinc-65 was added to  the water to give a concentration
of 8 x 10~5 microcuries per milliliter.  The animals
were removed periodically for counting and then re-
turned to the radioactive medium. A conversion factor
was needed to compensate  for differences in geometry
    100
                                             20
   Figure 11. Accumulation of Zn°-> by oysters and clams in
            an experimental marine environment.

-------
208
THE CONCENTRATION OF RADIONUCLIDES IN AQUATIC ORGANISMS
encountered in comparing activity in the animals and
in the water.   This factor was derived by first mea-
suring the activity in the animals directly in a whole
animal  counter,  secondly,  digesting the animals in
acid, and finally diluting to the same volume as that
of the sea water that was measured for activity.  An
average  of three  measurements yielded a factor of
0.77; that is, the sample counted 23 percentless when
dispersed in water, which was possibly the result of
the shielding effect of the water.  Clams accumulated
zinc-65 at a slower rate than oysters on a unit weight
basis (Figure 11).   At  the  completion of the experi-
ment, however, it was observed that these two curves
if extrapolated  would continue upward, indicating a
gradual but reduced uptake of zinc-6 5 in both clams and
oysters.  Thus, oysters concentrate zinc-65 to higher
levels than clams.  This increased amount of zinc-65
in oysters was possibly caused by a greater physio-
logical  demand for  this element than clams, as is
indicated by the  natural zinc  content  of these two
animals.

                     GOLD-199

   Molluscan shellfish are particularly  susceptible to
contamination by tagged radioactive sediments, since
these animals inhabit the bottom of estuaries and feed
by filtering particles from large volumes  of water.
Radioisotopes such as  gold-199 have been utilized as
tracers  in estuarine waters to determine the move-
ments of these  sediments (Krome,  1960).  Gold-199
was the isotope of  choice because  of its short half-
life, adsorptive power,  and detectability.

   To investigate uptake and accumulation of gold-199,
clams and their separated shells were placed in radio-
active water.  Another group of clams was placed in
bowls containing montmorillonite clay and these were
immersed in the sea water.  The clams and separated
shells  in the  water were  removed periodically to
determine their radioactive content, while those in
clay were counted at the end of the experiment so as
not to disturb the substrata.

   The  uptake  of  activity by both  clams and shells
was rapid during the first 14 days, followed by a much
 slower rate of uptake throughout the remaining time of
the  experiment  (Figure 12).   Clams contained 3.6
times as much activity than shells upon termination of
the  experiment.   This difference  was shown to be
 significant through a comparison of means by a t-test.
 The higher concentration in the clams was apparently
the  result of adsorption of the nuclide to their body
 surfaces and possibly  some contribution from meta-
 bolic processes.   The clams  in the montmorillonite
 clay contained 38  percent  less activity after 23 days
 than those in the water.  This lower activity conceivably
 was  caused by  the clams burrowing in the clay, pre-
 venting them from obtaining as much activity as those
 in the active water.

              RADIATION EFFECTS

    The importance of the effects of ionizing radiations
 on marine organisms has increased since the oceans
 have become a convenient area in which to dispose of
 radioactive  waste  materials  and  to  test  nuclear
                                     100,000 -
                                    02
                                    O
                                    ac
                                    iu
                                    a.
                                    ui
                                    i-
                                    2
                                    IU
                                    Q.
                                    V9
                                    g 10,000
                                                                -o	o	o—
                                                            SEPARATED SHELLS
                                       1,000 L
    048


Figure 12.  Accumulation of
                                                                        16
                                                                               20
                                                                                      24
 12
DAYS
  by clams and separated shells.
                                               to
                                      weapons.   This potentially harmful radiation  may
                                      originate either from the fission process itself or
                                      from  ingested  by-products of the  fission process.
                                      Thus, a reduction  of  harvestable living resources of
                                      the sea could conceivably  occur from the  effects of
                                      atomic radiations  on  organisms that are utilized in
                                      commercial fisheries or by a reduction in those fish
                                      that are utilized as food by these economic species.

                                        The following  experiments were undertaken
                                      determine the lethal doses at which 50 percen
                                      of the oysters and clams died.
                                        All animals were irradiated with a cobalt-60 source
                                      with a dose rate  of 350,000 roentgens  (r) per hour.
                                      The  radiation  chamber  was  a   cylindrical  cavity
                                      6 inches in diameter by 8-1/2 inches high.  Poly-
                                      ethylene  containers were  used to hold  the animals
                                      while being irradiated. After irradiation the animals
                                      were  returned  to  tanks of rapidly flowing sea water
                                      where  daily checks  were made for  mortalities.
                                         Fifty animals composed each group receiving the
                                      different dosages of radiation.  Oysters were exposed
                                      to 5,833; 11,666; 23,332;  46,664;  93,328 and 186,656
                                      roentgens.  Irradiation of clams was in similar groups
                                      except for three groups irradiated at 116,600, 139,992;
                                      and 163,324 roentgens.

                                        The cumulative mortality of the various groups of
                                      clams  is shown in figure 13.  There  were no mortal-
                                      ities in the  control groups of clams  or oysters.   The
                                      LDg0 for clams  in the various  dose groups  are:
                                      186,656 r - 5.5 days; 163,324 r  - 4.5 days; 139,992

-------
                                   The Effects of Radiation on Molluscs
                                                              209
   100
                          163,324 r  . 139,992 r  , 116,600 r
           10
                  20      30     40     50
                  DAYS AFTFR IRRADIATION
60
      70
  Figure 13. Doily cumulative percentage mortality of Mercenaria
           mercenaria subjected to graded doses of cobalt-60
           gamma radiation. (No mortalities in control).
 r - 6.5 days; 116,600 r -  25.5 days; 93,328 r - 38.5
 days.   The remaining groups of irradiated clams had
 not attained  a  50  percent mortality after 60 days.
    The LD50 for oysters (Figure  14) in the various
 radiation groups is:  186,656 r - 26 days;  93,328 r -
 34  days; 46,664 r - 36.5 days; 23,332 r  - 35 days;
 11,666 r - 40 days; and 5,833 r -  48 days.
    The physical state of materials introduced into the
 sea controls  the  role they play in the metabolism of
 marine  animals.   Radioactive  contaminants  occur
 either as particles or in solution. Particles may go
 into solution  depending  on the physical and chemical
properties of a particular  body  of water.  The dis-
 solved  substances may be precipitated as particles
of colloidal or  larger size either by co-precipitation
with other elements,  by sorption on organic or inor-
 ganic particles already in  the sea, or by interaction
with other sea-water constituents.  Thus,  both dis-
 solved  materials and particles  may be  ingested by
organisms  and  enter  into  the  biochemical  cycle.

   Availability  of radionuclides  for uptake by shell-
fish is  dependent in part on the chemical nature and
physical  state  of  the nuclides when present  in sea
water.    Radionuclides  can  further  be  categorized
according to the methods by which they are  produced,
that is  whether they are  products of  the  fission
processes or  neutron-induced.    The  four  radio-
isotopes  used in these investigations thus have  the
                                                                    10
 20     30     40     50
DAYS AFTER IRRADIATION
                                                                                                      60
                                                                                                            70
              Figure 14. Daily cumulative percentage mortality of Crassostrea
                       virginica subjected to graded doses of cobalt-60
                       gamma radiation.  (No mortalities in control).
              following classifications: Cesium-137, ionic; cerium-
              144, particulate  (both  fission products);  zinc-65,
              ionic;  gold-199,  particulate (both induced radionuc-
              lides).   Given data  indicate that the uptake of all the
              nuclides by these molluscs was basically the same,
              an  initial  rapid acceptance of the element  followed
              by  a  continued but  reduced  rate of uptake.  This
              initial  rapid  uptake  appears  to be a combination of
              physical adsorption on body  surfaces and metabolic
              processes  of the  animals.   The later,  continued re-
              duced  rate of uptake  is an  effect  of  the animals'
              metabolic  action,  since  saturation has_now been
              achieved through  sorption.    Loss of  these four
              nuclides showed a  similar pattern  as that  of  the
              uptake.

                Organisms take up from their environment and food
              and  incorporate into their bodies the elements needed
              for their maintenance, growth, and reproduction.  The
              proportions of  the  essential elements  required by
              organisms  are  different from the  proportions in  the
              environment.  This results in concentrations of some
              elements in the biosphere.   Molluscs differ in their
              uptake  of  the four  isotopes  mentioned.   The con-
              centration factor of an element has already been defined
              as the  amount of  an element in an organism in ratio
              to the quantity in an equal weight  of water.  Concen-
              tration factors  vary with season, with the concentra-
              tion of an element in water, with the concentration of
              other  metabolically  similar  elements,  with the  age

-------
210
THE CONCENTRATION OF RADIONUCLIDES IN AQUATIC ORGANISMS
of an  organism,  and with a  number of  other such
factors.  Also, the concentration of a nuclide depends
both upon the metabolic need of the particular organ-
ism  for  the element, and the tissue preference of the
nuclide.  Cesium-137 is accumulated to relatively high
levels by the soft tissues other than muscle, but in
time  the highest  concentrations are reached by the
muscle.  It was found that clams concentrated cesium-
137 to a higher level than oysters, which is in agree-
ment with the differences in their body structure as
regards  muscle tissue.
   Whether  or  not the radionuclide occurred in the
ionic  or particulate  state in sea  water made  little
difference in its uptake by the three groups of shell-
                                     fish.    If  the particulate  radionuclides  cannot be
                                     metabolized by the animals they may adsorb to body
                                     surfaces or associate with  the organs and structures
                                     connected with the digestive tract.  Such an accumu-
                                     lation  of radioactive  particles may be important for
                                     purposes of passage  through food webs to man.  The
                                     fact that the adductor muscle of scallops and all the
                                     soft tissues  of oysters  and clams  are  eaten  allows
                                     for the ingestion of many radionuclides that may not
                                     be  metabolized and incorporated  into the tissues of
                                     these shellfish.   Many nuclides are concentrated by
                                     the shells of these animals.  Accumulation of radio-
                                     activity by shells may be  important  since they  are
                                     placed on the bottom by oystermen as  cultch to which
                                     the young oyster spat attaches; they are also used in
                                     many other industries.
                                              REFERENCES
 Chipman, W.  A.,  T. R.  Rice, and T. J,  Price.  1958.
 Uptake and accumulation of radioactive zinc by marine
 plankton, fish, and   shellfish.   Fish.   Bull.  135,
 U.S. Fish and Wildlife Service, 58: 279-292.

 Goldberg, E, D. 1952.  Iron assimilation by marine
 diatoms, Biol. Bull., 102: 243-248.

 Greendale,  A. E., and N. E. Ballou.  1954.  Physical
 state  of fission  product  elements  following their
 vaporization in distilled water and sea water. U. S.
 Naval Radiological Defense Lab., San Francisco 24,
 Cal. VSNRDL-436. 24 pp.

 Hood,  S. L., and C.  L. Comar.   1953.  Metabolism
 of  cesium-137 in laboratory and domestic  animals.
 U.  S. Atomic Energy Comm., Doc. No. ORO-91. 31 pp.

 Krone, R0 B.  1960. Third annual progress report on
 the silt transport studies utilizing radioisotopes.
 Hydraulic  Engineering Laboratory  and  Sanitary En-
 gineering  Research Laboratory,  University  of Cal.,
 Berkeley. 52 pp.

 Lowman, F.  G.,  R.  F. Palumbo,  and  D.  J. South.
 1957.   The occurrence  and distribution of radioactive
 non-fission products  in plants  and  animals of the
 Pacific proving grounds.  Univ. Wash., Applied Fish.
 Lab.,  Report No. UWFL-51. 61 pp.
                                      Rice,  T.  R.  1953.  Phosphorus exchange in marine
                                      phytoplankton.  Fish.  Bull. 80, U0  S, Fish and Wild-
                                      life Serv.,  54: 77-89.
                                      Rice, T.R. 1956.   The accumulation and  exchange of
                                      strontium by planktonic  algae.  Limnol.  Oceanogr.,
                                      1:123-138.

                                      Rice, T.R., and Virginia M. Willis,  1959. Uptake, ac-
                                      cumulationl and loss of  radioactive  cerium-144 by
                                      marine planktonic algae. Limnol. Oceanogr., 4:227-290.

                                      Seymour,  A. H.,  E. E. Held, F.  G. Lowman, J. R.
                                      Donaldson, and Dorothy  J.  South.  1957.  Survey of
                                      radioactivity  in  the sea and  in  pelagic marine life
                                      west of the Marshall Islands, September 1-20,  1956.
                                      Univ. Wash., Applied Fish. Lab., Report No. UWFL-47.
                                      57pp.

                                      Vallee, B.  L.   1959.  Biochemistry, physiology, and
                                      pathology  of  zincu    Physiol.  Rev. 39:   443-490.
                                      Vinogradov, A. P.   1953.  The elementary chemical
                                      composition of marine organisms.  Memoir,  Sears
                                      Foundation of Marine Research, Number II, New Haven.
                                      647 pp.
                                      Welander, A. D.   1957. Radiobiological studies of the
                                      fish collected at  Rongelap  and Ailinginae  Atolls.
                                      July 1957. Univ. Wash. Applied Fish. Lab., Report No.
                                      UWFL-55.  30 pp.

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                              Accumulation of Radionuclides by Aquatic Insects
                                               211
                    ACCUMULATION OF RADIONUCLIDES BY AQUATIC INSECTS
                                               J. J. Davis *
   The literature contains re suits of numerous studies
of insect  control, physiology,  and ecology in  which
radionuclides were  used as tags.  The relatively few
such studies that  have dealt with aquatic insects per-
tained mainly to the use of radioactive "tags" in study-
ing dispersion of economically important forms such
as  mosquitoes and  black flies (Hassett and Jenkins,
1949; Bugher and Taylor, 1949; Jenkins,1949; Thurman
and Husbands, 1950;  Shemanchuk, Spinks, and Fredeen,
1953; Fredeen, etal., 1953; Gillis,  1962).

   The section of the Columbia River  that is within
the Hanford Reservation in southeastern Washington
provides a unique opportunity for studying accumula-
tion  and cycling of radionuclides  in natural aquatic
communities.  More than 60 radionuclides have been
identified in the aqueous effluents that are continuously
discharged into the  Columbia River from some of the
Hanford reactors.   Many of these, because of their
infinitesimal initial  amounts in the effluent water sand
extremely  short radioactive half-lives, are not detect-
able in the river. About 20 of them have been measured
in some river  organisms  collected within 1  mile
downstream from the reactor outfalls.  (Davis, etal.,
1958).

   Insects  living in the  river below reactor outfalls
are  many  times more radioactive than is the water
they inhabit.  For example, larvae  of  the caddis fly
Hydropsyche  cockerelli    Banks  collected  within  3
miles downstream from reactors, commonly have a
gross beta radioactivity  1,400 times greater than that
of the water.  Due to metabolic selection,  the quantities
of radionuclides accumulated by insects are different
from those of the water. The five most abundant radio-
nuclidesin insect larvae, in decreasing order, arephos-
phorus-32,  copper-64, chromium-51, zinc-65, and
sodium-24 as compared to copper-64, neptunium-239,
sodium-24, manganese-56, and chromium-51 in milli-
pore-membrane-filtered river water  from the same
collection site.  A typical  accumulation factor pattern
of  these  radionuclides   in  Hydropsyche cockerelli
larvae during  the late summer (water  temperature
about 18°C) is shown in Table 1.

   An organism's location in the food web, its trophic
level, may affect the amount of radionuclides accumu-
lated.  The magnitude  of  this influence is dependent
upon several factors. Of paramount importance is the
time required for the radioactive material to pass from
water to the organism in question.  The accumulation
efficiency and transport time of radionuclides are,  in
turn,  dependent upon metabolic demand and the bio-
logical turnover rate (biological half-life) of the ele-
ment  for  each component in the food  web (Davis and
Foster, 1958).  And last, the degree to which transport
time influences the efficiency of transfer depends upon
the physical  half-life of  the  radioisotope  involved.
Long-lived radionuclides  such as  strontium-90 (28-
year  half-life),  cesium-137 (30-year half-life)  or
carbon-14 (5770-year  half-life), of course, would  be
essentially unaffected.

   An  example  of the  pronounced differences that
commonly occur in amounts of radionuclides accumu-
lated  by  different species of insects  from the same
habitat is shown in Table 2.  These differences are
caused by an  interplay of ecological and metabolic
factors.   The  most influential factors are probably
food habits and biological turnover rates (biological
                  Table 1. RADIONUCLIDE ACCUMULATION FACTORS FOR CADDIS FLY
                                    LARVAE FROM COLUMBIA RIVER
Radionuclide
P32
Zn65
Cr51
Cu64
Na24
Np239
Mn56
Physical
half-life
14.3 days
245 days
27.8 days
12.9 hr
15 hr
2.3 days
2.58 hr
Accumulation factor
(radioactivity/g larvae, live weight)
radioactivity/ml water
100000
20000
3000
400
80
30
not detectable in insect
* Biology Laboratory, Hanford Laboratories, General Electric Company, Richland, Washington

  (Work performed under Contract Number at (45-l)-1350 between the General Electric Company and the Atomic Energy Commission,
  Division of Biology and Medicine.)

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 212
THE CONCENTRATION OF RADIONUCLIDES IN AQUATIC ORGANISMS
               Table 2.  RADIONUCLIDES IN PLANKTON AND IMMATURE INSECTS FROM
                        THE COLUMBIA RIVER NEAR HANFORD, FEBRUARY, 1957
                                       (In units of pc/g wet wt.)
en

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                             Accumulation of Radionuclides by Aquatic Insects
                                                                           213
 Table 4. RADIONUCLIDE CONTENT OF CADDIS
   FLY LARVAE (Hydropsyche cockerelli) FROM
COLUMBIA RIVER DURING SUMMER AND WINTER
Radionuclide
Na24
p32
SC46
Cr51
Mn54
Fe59
Co60
Cu64
Zn65
As76
Zr95_Nb95
Rul03
BaHO
Lal40
Np239
pc/g wet wt.
February
120
4200
56
860
100
19
30
310
730
150



170

August
710
24000
71
6000
79

2
7100
2000
520
66
110
42
350
310
                            a radioactivity  plateau (16 namocuries/g wet weight),
                            and cut into short lengths to improve availability to
                            the  larvae.    Comparable results were reported by
                            Whittaker (1961) from a study  of P32 movement in
                            an experimental outdoor pond.   He  found  an initial
                            algae-to-mayfly nymph  transfer  rate  (p32 concen-
                            tration  in mayflies/p32  concentration  in  algae) of
                            0.01  per hour.  Whittaker's data show that the may-
                            fly nymphs did not reach peak radioactivity until the
                            fourth day; however,  in  his  experiment, the isotope
                            was introduced into an established ecosystem so that
                            the  algae did  not  reach peak radioactivity until  the
                            fourth day.

                              Much remains to be learned about the influence of
                            water chemistry upon radionuclide uptake by aquatic
                            insects  and other  organisms. Treherne (1954) found
                            that raising the sodium  content of water from 4 to 8
                            milliequivalents per  liter or the potassium content
                            from 0.159 to  4.00 milliequivalents per liter did  not
                            change  the rate  of  sodium-24  uptake  by  mosquito
                            larvae.
                     10.000
                      1000
                        16

                        12

                         8

                         4

                         0

                        10


                         5
                           River Water Temperature
"-   O-
\
                                                   \
                                                           River Water Radioactivity
                                                 L
                               I
                                        M
                      M   J    J
                     Figure 1. Beta-emitter concentration in caddis fly larvae (Hydropsyche cockerelli)
                             and plankton from Columbia River.

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214
THE CONCENTRATION OF RADIONUCLIDES IN AQUATIC ORGANISMS
                          12
                                      18
                                                 24
   Fi gure 2. Uptake of beta emitters from reactor effluent water
           by caddis fly larvae (Hydropsyche cockerelli).
                                          I have investigated the influence of isotopic dilution
                                       upon phosphorus-32 accumulation in aquatic organisms
                                       by introducing the same trace amount of phosphorus-32
                                       but differing quantities of stable phosphorus into each
                                       of  four troughs  containing established  stream-type
                                       ecosystems.   The biotic community was obtained by
                                       placing cobblestones supporting  algae  and  inverte-
                                       brates, Elodea,  snails  (Radix), and juvenile suckers
                                       (Catostamus) into the indoor troughs of flowing water.
                                       The phosphorus-32 was metered into a common head
                                       tank of raw river water,  which was discharged into
                                       each trough at the rate  of 0.1  microcurie per minute.
                                       The levels of stable phosphorus tested in the troughs
                                       were  0.01, 0.056, 0.22, and  1.01  ppm.  These were
                                       maintained by continuous  metered addition  of dilute
                                       phosphoric acid.   Water temperature was maintained
                                       constant at 13°C. After 32 days of continuous adminis-
                                       tration  of stable  and  radioactive  phosphorus,  the
                                       experiment was terminated and the biota analyzed for
                                       phosphorus-32.

                                           The levels found in caddis fly larvae, fish (entire
                                       minus  gut content), and sessile diatoms  are  shown in
                                       Figure 3.  Similar patterns occurred for other organ-
                                       isms  such as Potamogeton, Elodea, and snails.  These
                                       results indicate  a nearly linear  reduction  of phos-
                                       phorus-32 uptake  with  increase of phosphorus in the
                                       water.
                                 100
                                  10
                            E
                            i_
                            O
                            i_
                            s.
                                 0.1
                                                   Sessile Dialoms
                                                Juvenile Suckers
                                                  (Catostomus)
                                                   Caddisfly Larvae
                                                    (Hydropsyche)
                                    0.01
                                                           0.1

                                                          ppm P
                     Figure 3. Effect of stable phosphorus concentration in water on P32 uptake by caddis fly larvae
                             (Hydropsyche cockerelli), fish, and sessile diatoms.
                                                                                                    GPO 816-361-8

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                             Accumulation of Radionuclides by Aquatic Insects
                                               215
                                             REFERENCES
Bugher, J. C., and M. Taylor. 1949. Radiophosphorus
and radiostrontium in mosquitoes.  Preliminary re-
port, Science 110:  146-147.

Davis, J. J., R. W. Perkins, R. F. Palmer, W. C. Han-
son, and J. F. Cline.   1958.   Radioactive materials
in aquatic and terrestrial organisms exposed to reactor
effluent water.  Proc. 2nd Intern. Conf. on the Peaceful
Uses  of Atomic Energy, United Nations, Geneva, 1
September-13 September, 1958, 18: 423-428.

Davis, J.  J., and  R.  F. Foster.   1958.  Bioaccumu-
lation  of  radioisotopes through aquatic  food chains.
Ecology 39 (3):  530-535.

Fredeen,  F.  J.  H., J. W. T. Spinks,  J. R. Anderson,
A. P.  Arnason, and J. G. Rempel. 1953.  Mass tagging
of black flies (Diptera:  Simuliidae)  with radiophos-
phorus. Can. J. Zool., 31: 1-15.

Gillis, M. T.  1962. Marking and release experiments
with a tropical  mosquito by the use of radioisotopes,
p. 267-281.  Radioisotopes in tropical medicine. In-
ternational Atomic Energy Agency, Vienna.
Hassett,  C. C., and D. W. Jenkins.  1949.  Production
of radioactive  mosquitoes.  Science 110:  109-110.

Jenkins,  Dale W.  1949.   A field method of marking
Arctic mosquitoes  with  radiophosphorus.  J.  Econ.
Entomol. 42(6):  988-989.
Shemanchuk,  J. A.,  J.  W. T.  Spinks,  and F. J. H
Fredeen.  1953.  A method of tagging prairie mos-
quitoes  (Diptera:   Culicidae) with radiophosphorus.
Can. Entomol.  85(7): 269-272.

Thurman, D.  C., Jr., and R. C. Husbands. 1950. Pre-
liminary report on mosquito flight dispersal studies
with radioisotopes  in California. U. S. Public Health
Service,  Communicable Disease Center Bulletin, 10(4):
1-9.

Treherne, J.  E. 1954.   The  exchange  of labelled
sodium in the larva of Aedes aegypti L. J. Expt. Biol.
31(3):  386-401.

Whittacker,  R. H.  1961.   Experiments  with  radio-
phosphorus tracer  in aquarium microcosms.   Ecol.
Monographs 31:  157-188.

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216
                  THE CONCENTRATION OF RADIONUCLIDES IN AQUATIC ORGANISMS
                 RELATIONSHIPS BETWEEN THE CONCENTRATION Of RADIONUCLIDES

                                 IN COLUMBIA RIVER WATER AND FISH
                                       R. F. Foster and Dan McConnotf
                  INTRODUCTION
   The possibility that fish might pick up radionuclides
from water containing radioactive  wastes was  rec-
ognized during the conceptional stage of the atomic
energy era.  This early recognition was prompted by
considerations of the  several  ways by which people
might  be exposed to radioactive liquid effluents in
the vicinity  of the major atomic  energy  installa-
tions and the  possible effect of radioactive effluents
on valuable aquatic resources.  The work of Prosser,
etal.  (1945) on  the accumulation of fission products
in goldfish, was probably the first work in this specific
field that was motivated by radiological considerations;
it was soon followed by laboratory programs  at the
University of  Washington  (Welander, 1945), and at
the Hanford site (Foster, 1946).   During  the last
decade many  additional programs concerned with the
accumulation  of  radioactive materials in fresh water
and  marine forms have become well established in
the biological laboratories of universities and govern-
mental agencies throughout the world.

   Much of  the current experimental work on radio-
nuclides  in  fish continues to be  stimulated by the
potential  effect  of  the  radionuclides  on the fish
or the exposure  of people  who may eat them. Funds
are justified,  at least partially, on this basis.  The
cause remains a worthy one since actual field experi-
ence at major atomic energy sites has usually shown
that  the  accumulation of one or a few radionuclides
by aquatic forms that are  eaten in quantity by man
proves to be  the factor which limits the quantity of
radioactive  material that may be released to surface
waters, t

   After some 20 years of recognizing the problem we
have learned something about the mechanisms of uptake
and the turnover rates for a few radionuclides in fish.
We have also  speculated a great deal about "concen-
tration factors" and  their importance in predicting
allowable rates of release of radionuclides. However,
when we are  faced with new practical problems of
applying concentration factors in order to estimate the
level of  specific nuclides that may result in fish as a
consequence of known amounts in the water, we find
that the best available information is rarely the product
of controlled laboratory experimentation.  Rather, the
most usable  information  stems from field surveys
made near the major atomic energy installations or in
the Pacific Test area. The conclusion is obvious -  we
need more experiments designed to simulate closely
field conditions and also greater exploitation of the
data that can be  derived from existing conditions.
This paper is intended as a contribution in the second
category and utilizes  recent data obtained from the
environmental surveillance program of the Columbia
River downstream from the Hanford plutonium pro-
ducing reactors.  Data of a somewhat similar nature
obtained in previous  years have been  presented on
several occasions (Foster and Davis, 1955; Davis, etal.,
1958).
 RADIONUCLIDES IN COLUMBIA  RIVER WATER
   Cooling of the Hanford reactors by direct  use of
filtered Columbia River water in a single pass system
results in the formation of different neutron activation
products,  which  enter the  Columbia River  with  the
effluent  water.   For the most part,  these are not the
same radionuclides that characterize world-wide fall-
out because they are not fission products.  Relatively
small  amounts  of fission products are also present,
however, because of the fissioning of natural uranium
present  in the  river  water,  because  of occasional
ruptures of the jackets of the fuel elements, and be-
cause  of fallout.  A description of the characteristics
of the reactor effluent and how it is handled  has been
reported previously (Foster, et al., 1961).

   Before  dilution with the main flow of the Columbia
River,  more than 60 different radionuclides can be
identified in the reactor effluent.  After dilution and
transport by the river some 40 miles downstream from
the reactors, about a dozen of the nuclides can still
be  measured  by  routine  laboratory  methods with
reasonable success.   Figure  1  shows the relative
abundance of the dominant radionuclides at three points
below  the reactors:  Hanford Ferry  (5 to  20  miles
below reactor outfalls), Pasco (35 to 50 miles below the
outfalls), and Vancouver (about 260 miles below  the
outfalls).  The  relative concentrations of the several
radionuclides shown  changes rapidly with time (and
distance) principally because of radioactive decay of
the shorter-lived nuclides. For completeness, a list
of all  the  radionuclides that have been identified in
the reactor effluent is provided in Table 1.

   The  concentrations of radionuclides in the  river
fluctuate  widely between  seasons.   This  is  partly
because  of variations in  the physical  and chemical
characteristics  of the river water and thus the material
available for activation in the reactor, but the dominant
factor  is river  flow  which  is low  (about 50,000 cfs)
in midwinter and high (400,000 to  500,000 cfs  at  the
peak) during the  spring freshet.  Figure 2 shows  the
concentrations   of  the  seven most  abundant radio-
nuclides in the  Columbia  River  at Pasco for 1961
and the first quarter of 1962. The material presented
in the  next section will show that  the  concentration
of radionuclides in the  fish bears very little resem-
blance to that shown in Figure 2.
 * Radiation Protection Operation, Hanford Laboratories Operation, General Electric Company, Richland, Washington.
  (Work performed under Contract No. AT(45-1)-1350 between the U. S. Atomic Energy Commission and the General Electric Company).

 T Curre nt estimates of the fraction of permissible radiation exposures that can result from the use of Columbia River water and fish
  downstream from the Hanford plant are reported by Nelson (1962).

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                             Radionuclides in Columbia River Water and Fish
                                                                                                      217
                       HANFORD FERRY
                        (6X10-5jJC/cm3)
                        PASCO
                   (1.5X10-5pC/cm3)
                                                                             VANCOUVER
                                                                           (2.4X10-6pC/cm3)
                          Figure 1. Relative abundance of radionuclides in Columbia River water.

              Table 1. RELATIVE ABUNDANCE OF REACTOR EFFLUENT RADIONUCLIDES
                                 (Reference Time - 4 Hours Postirradiation)
Major, 90%
Mn56

Na24
Cr51
Np239
Si31







Minor, 18%
Zn69
Ga72
Sr92
U239
1133
Y92
Nb97
Zn65
p32
Y90
1135
Y93


Trace, 2%
Eu152
Sm153
W187
Lal41
Ndl49
La140
X132
Bal40
Mo99
Sm156
Sc46
Q(jll5
Ce^43
Pml47
jl31
fp*
"Dy>X4u
Cl4
Ndl47
Aglll
Fe59
Sr89
Mn54
Zr95
Pm149
Eu156
Ce-Pr144
Pr145
Pm151
Co60
Pr143
RulOS
Sc47
Sr90
SrS85
U238
Pu239
Ac22?
P0210
Tb160
Co58
    RADIONUCLIDES IN COLUMBIA RIVER FISH
   Some radioactive  materials can be detected in all
species of fish (and other aquatic life, for that matter)
in the Columbia River (Olson and Foster, 1952).  There
are, however, significant differences in the quantities
of particular radionuclides present in different species
(Davis,  et al., 1958).  A number of reasons for this can
be advanced (Davis  and Foster,  1958), but two of the
most obvious are food  habits and migratory habits.
   In order to clarify the relationship between the con-
centration of radionuclides in the water and in the fish
it is desirable to  avoid the introduction of unnecessary
variables.  For this reason, this discussion is confined
to a single  game species of fish, the Rocky Mountain
whitefish  (Prosopium williamsoni),  sampled from a
20-mile stretch of the Columbia River (Hanford Ferry
to Richland); only the muscle tissue of adult specimens
is included.   Figure 3 shows an approximation of the
radionuclide content of the  muscle  of such speci-
mens collected during the fall of 1961, the time of the
year when the highest  concentrations are observed.
The phosphorus-32 and zinc-65 clearly contribute the
greater part of the radioactivity.  For comparison, the
radionuclide content of the Columbia River water at
the same  season and location  is also presented in
Figure 3.  The differences between the relative amounts
of radionuclides  in the  water and in the fish are ob-
vious.   The areas of the circles in Figure 3 are pro-
portional  to the total radioactivity of the  water and
the fish they represent.  Several of the nuclides that
are relatively abundant in the water  are  not easily
measured in the f ish,and some nuclides readily detected
in the fish, such as cobalt-58, cobalt-60 and naturally

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218
THE CONCENTRATION OF RADIONTJCLIDES IN AQUATIC ORGANISMS
     100 F
  U
  3
  g
  a
             I      F      M     A      MJ      J       AS      ON      D-J      F      M
     0.01
                   Figure 2.  Concentrations of several radionuclides in Columbia River water at Pasco, Washington.
                      WHITEFISH FLESH
                         (1X10-3 JJC/g)
                                                                      WATER
                                                                 (1.5X10-5 JjC/cm3)
                                                                           OTHERS
                                                           Zn65
                                                           N024
                                                           OTHERS
                                                           Co58 and Co°0
                                                           K40
                                                                                                             G51
                    Figure 3.  Radionuclide composition of whitefish flesh end Columbia River water, Fall 1961.

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                             Radionuclides in Columbia River Water and Fish
                                                                                                       219
occurring potassium-40, are not easily measured in the
water.  It must be stressed that Figure 3 provides only
an approximation of conditions that existed at a given
time.   The ratios actually change quite rapidly from
week to week.

   The wide variations encounteredbetween specimens
caught  at  the  same time  and place and at different
seasons of the year are shown in Figures 4 and 5 for
phosphorus-32  and zinc-65, respectively. As shown in
Figure 4, the range in the concentration of phosphorus-
32  in  fish collected on a  particular day commonly
extended  over  an  order  of  magnitude.  On rare
occasions  the range was spread  over  two  orders of
magnitude.  Within a year the difference between the
most-  and least-radioactive  fish may approximate
1000. Such wide variations  should discourage investi-
gators from drawing sweeping conclusions on the basis
of spot samples  of a few fish taken once or twice a
year. Data presented in Figure 4 are for one  species
of fish;  inclusion of  other species would serve to
widen the variation still more. A contributing factor to
the observed variation is  the  relatively  short  (2-
week)  half-life  of  phosphorus-32.   This means, in
effect,  that the  phosphorus-32  content  of the  fish
reflects  the fish's experience with  this radionuclide
over the previous 1 or 2 months. While an appreci-
able  amount of integration  of the intake and loss of
phosphorus-32  takes place  in this interval, it is still
too short a time to  smooth out fluctuations resulting
from major changes in feeding rates and migrations
and emigrations  from the  section of the river where
the phosphorus-32 is most abundant.
   Variations in the zinc-65 content of the fish, while
still quite large, are not as great as for phosphorus-32.
Figure  5 shows a  seasonal fluctuation of  about  10
fold,  compared with about  50 fold for phosphorus-32
in the same fish. The radioactive half-life of zinc-65
is about 9 months;  thus  the zinc-65 concentration in
the fish may reflect an integrated experience over a
much longer time interval than for phosphorus-32.
The biological turnover, however, of zinc-65  probably
has a greater effect on the accumulated body burden
than the radioactive  half-life.

   FACTORS AFFECTING THE PHOSPHORUS-32
               CONTENT OF THE FISH

   The  two dominant modes  by which radionuclides
in the water reach the flesh of fish are quite obvious;
one  is  direct absorption through the gills  or  other
external surfaces into the blood stream,  and  the other
is ingestion  and assimilation with food.  The relative
importance  of these  twc  modes differs  greatly with
different elements and carefully controlled laboratory
work  is necessary  for  a  satisfactory resolution.
Nevertheless, field data, such as that shown in Figures
4  and  5, provide  useful  clues.  The phosphorus-32
data have been selected for further analysis at this
time because supporting information is more complete
than for zinc-65.

   The seasonal variations in the phosphorus-32 con-
tent of  Columbia  River  fish (Figure 4) have been
attributed principally to variations in the intake rate
of phosphorus-32  with food  organism.   (Davis and
                5000
                            I	L_J	L_J	I	I
                      JFMAMJJASOND
                                         1961
                Figure 4.  Concentration of P32 in the flesh of whitefish caught between Hanford Ferry and Richland.

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220
THE CONCENTRATION OF RADIONUCLIDES IN AQUATIC ORGANISMS
                   1000 -
                                                                            J   F   M
                                                                              1962
                                Figure 5. Concentration of Zn65 in the flesh of whitefish.
Foster, 1958).  It  should be recognized,    then,
that the  availability of phosphorus-32 to the fish  is
greatly influenced by  complex  ecological relation-
ships that involve all the components of the food base
for the fish.  While a detailed resolution of this prob-
lem would  be most interesting, a first  approxima-
tion of the water-fish relationship can be worked out
even though knowledge of the food supply of the fish is
incomplete.  Such an approximation is attempted here.

   Watson (1957)  has  shown that phosphorus-32 once
deposited in fish  diminishes very  slowly - in effect,
at about the rate  of radioactive decay of the nuclide.
Therefore, the amount of phosphorus-32 observed in
Columbia River fish can be viewed as a consequence
of  two  primary  factors:   one, the  amount  the fish
contained a few days prior  to sampling, which can be
considered  as a  base;  and two, the amount of new
phosphorus-32 acquired during a few day's time,which
is added  to the base.   For convenience, 1 week was
selected as an appropriate period over which the rate
of change or acquisition of new phosphorus-32 would
be studied.

   With the curve plotted in Figure 4 as a basis, the
amount of new phosphorus-32 acquiredby the fish each
week throughout  the 15-month period was computed
(with proper allowance  for radioactive decay).  The
result is plotted in Figure 6.   Between  January and
mid-March,  1961, the fish  acquired  little to no new
phosphorus-32 and the concentration in the flesh de-
clined at essentially the radioactive decay rate of the
nuclide.   The fish took in  a small quantity of phos-
phorus-32 in April of 1961, but it was not until July
that the intake rate increased markedly. The maximum
                                      rate  of intake occurred about the first of November,
                                      and thereafter it diminished rapidly.

                                         Figures 4 and 6 do not take into account the fact
                                      that the concentration of phosphorus-32 in Columbia
                                      River  water fluctuates  with time.   Obviously the
                                      amount of phosphorus-32  that can be acquired by the
                                      fish  is  dependent upon the amount available in the
                                      water,  even  though  a food  chain  is  operative as a
                                      vector.  Figure 2 shows the measured concentrations
                                      of  phosphorus-32 in the Columbia River water just
                                      downstream from the section of the river from which
                                      the whitefish were  taken.   The minimum values,
                                      which  occurred  in  June  and July,  reflect  a high
                                      discharge into the river.   Lesser  amounts of phos-
                                      phorus-32 were  introduced into the river during the
                                      last quarter of 1961 than during the first quarter  (Fig-
                                      ure 2).  The effect of this fluctuating concentration of
                                      phosphorus-32 in the river water on  the rate of up-
                                      take  by the  fish can largely be removed by adjusting
                                      the data  plotted  in Figure 6 to an assumed uniform
                                      concentration of  one micromicrocurie of phosphorus-
                                      32  per cubic centimeter of water.  Figure 7 shows
                                      the rate of uptake of phosphorus-32  by the  fish (in
                                      terms  of picocuries of phosphorus-32 per gram of
                                      fish per week) per picocuries of phosphorus-32 present
                                      in  a cubic  centimeter of river water.  It  should be
                                      remembered that this relationship is largely empiri-
                                      cal.  Although it excludes the role of the food chain,
                                      the shape  of the  curve emphasizes  its existence.

                                         The data in Figure 7 have been plotted in such a
                                      manner that the curve would be a horizontal line if
                                      there were  a simple direct relationship (e.g.  con-
                                      stant  proportionality)  between  the  concentration of

-------
                            Radionuclides in Columbia River Water and Fish
                                    221
                  J     FMAMJ     J    ASOND
                                            1961
J    F    M    A
      1962
                       Figure 6.  Rat at which new P32 wos deposited in the flesh of whitefish.
U
 a.
     1400
     1200
     1000
      200
                   F     M     A     M     J     J
                                             1961

       Figure 7.  Deposition of P^2 in fish related to river stage and temperature - rate per picocuries of P" per cubic
                                               centimeter of water.

-------
222
                  THE CONCENTRATION OF RADIONUCLIDES IN AQUATIC ORGANISMS
phosphorus-32  in the water and the quantity taken up
by the fish per unit time. Since this is not the case,
some interpretation  is  in order.   It has been pro-
posed that temperature, as a dominant factor affecting
metabolic  rate, strongly influences the rate  of ac-
cumulation of radionuclides (Davis and Foster, 1958).
In order to observe the temperature vs. phosphorus-32
accumulation  relationship  for the adult whitefish,
the temperature of the Columbia  River  water has
been plotted in  Figure 7. The relationship is obviously
not entirely consistent, but certain features are evi-
dent.    At temperatures  below 5°C uptake  of phos-
phorus-32 is very slow, and the maximum rate of up-
take occurs in the range of  12°  to 16°C.  It is not
known   whether the  slower-than-maximum uptake,
which  occurred in  August when the  water was the
warmest, resulted from temperatures above  optimum
for this species, from a less favorable food supply,
or  for  some other reason.  For comparable temp-
eratures, the  rate  of uptake  of phosphorus-32 was
much greater in the fall than in the spring.

   Since the stage  of  the  river can  have  a heavy
influence on the availability of food  for the  fish, a
plot of  the river discharge is also included in Figure
7.   The  usual high flow,  caused  by  melting snow,
occurred in May and June.   This  spring freshet is
accompanied by high turbidity,  shifting of  the  sub-
strate,  and increased  velocities,  all  of which are
detrimental to  the food base.  Re-establishment of
an  adequate food  supply after the spring run-off
could easily account  for the  rapid rise  in  uptake
of phosphorus-32 by the  whitefish during July.  The
phosphorus-32  curve in Figure 7 is unaffected by river
flow  in the sense  that  it  affords  dilution of the
radioactive materials, since the data plotted  in this
figure  have already been adjusted to a uniform con-
centration of phosphorus-32 in the water.

            CONCENTRATION FACTORS

   For  the purpose  of predicting the  concentration
of certain radionuclides in fish that  results when
there is continuous  discharge of a radioactive effluent,
it is  convenient  to apply  "concentration  factors"
that express the expected level  in  the  fish as some
multiple of the level in the  water.    For common
elements theoretical  concentration factors can be
derived  from  quantitative   measurement  by  con-
ventional chemical  analysis  of the stable isotopes in
both the water and the fish.   Field experience with
radioisotopes  has shown that  the theoretical  values
are not  usually  reached.

   The variable rate of accumulation of phosphorus-32
in whitefish flesh shown in Figure 7 indicates a similar
seasonal variation  in the concentration factor.  The
dimensions of  Figure  7 are, of  course,  not quite
those of the conventional concentration factor (micro-
curies per gram of fish in relation to microcuries
per cubic centimeter of water), but they differ only by
a  constant needed  to convert  the rate of  uptake
(microcuries of phosphorus-32 per gram per week) to
the ultimate equilibrium level that this rate would
yield.   On the  basis  that phosphorus-32 is  depleted
from the fish only  by radioactive  decay with a half-
life of   2  weeks,  the  needed correction factor is
3.5.   The concentration factor for the flesh of adult
whitefish  under conditions prevailing in the Columbia
River can, then, be stated as ranging from essentially
zero  during the coldest period of the year to about
5,000 in October.  The maximum of 5,000 would only
be observed, however, if the maximum  rate  of up-
take (1400 picocuries of phosphorus-32 per gram per
week) continues for nearly a month in order for  an
equilibrium to be reached.  For all practical purposes
this did occur in 1961.

   The  rate of uptake  curve shown in Figure 7 has
another interesting feature  related to concentration
factors.    The fact that there   is no  well-defined
plateau  associated with the maximum values suggests
that appreciably different peaks are likely to occur in
other years  when  ecological  conditions  might  be
more or less favorable. Thus, the concentration factor
of 5,000 calculated for 1961 is not necessarily appli-
cable to other years.

   A  more  direct and less sophisticated method  of
arriving at  the  maximum concentration factor for
phosphorus-32 is merely to take the maximum ob-
served concentration of phosphorus-32 in the fish and
divide it by  the concentration observed  in the water
at about the same  time.  In this  case, one should not
merely  use the concentration in the water at the time
the fish were  sampled, but rather  a value which is
more representative of conditions over  the interval
of time during which the fish acquired its burden of
the radionuclide.   For example,  if  the values shown
in Figure 4  (900  picocuries  of phosphorus-32 per
gram of  fish in late November)  and Figure  2 (0.23
picocuries of phosphorus-32 per cubic centimeter of
water) are used, a concentration factor of about 4,000
is obtained.

   Concentration factors for zinc-65 cannot  at this
time  be derived on a basis of intake  rates because
adequate data on turnover  of zinc-65 in fresh water
fish are not available. Values can, however, be derived
on the basis of the ratio of the concentration of zinc-
65 in the water to that in the fish.  With the zinc-65
concentrations in  whitefish flesh shown  in Figure 5
and the concentrations in the water shown in  Figure
2, a maximum  concentration factor of about 1000 is
obtained; this occurs in November.

   Concentration factors  for the  other radionuclides
often observed in the  whitefish flesh can be stated
only  in vague terms  because  of  the  difficulty  in
measuring  them  at their  relatively low  levels  in
samples  processed  on  a "production-line"  basis.
The  half-life of sodium-24 is so short (15 hours) that
any appreciable delay in processing samples requires
the application of large correction factors.  The short
half-life  also   greatly limits  the  fraction  of this
nuclide  that can  enter the fish via  complex  food
chains.    On the basis of the limited  data available
at this  time, however, the  concentration factor for
sodium-24 between water and whitefish flesh appears
to be  in the  range of 100 to 500.

   Cobalt-58 and  -60  constitute  an interesting case
since the  level of these nuclides in the river water is
below the  detection level  of the laboratory techni-

-------
                            Radionuclides in Columbia River Water and Fish
                                                                                                      223
ques used for routine samples.  Extrapolation from
limited data  on  the  rate of release of these nuclides
into  the river would,  however, place the order of
magnitude  of the  concentration  factor  at  10,000.

   Of the  more  abundant  radionuclides in the water
(see Figure 3),  copper-64, and arsenic-76 have such
short half-lives (13 hours and 26  hours, respectively)
and  limited  direct uptake from the water that they
are  not readily detected  in fish samples processed
by routine methods.   Available data  indicate  that
the concentration factors for these nuclides are some-
thing less than 10.

   The  half-lives of chromium-51 and neptunium-239
are  28 days  and 2.3  days,  respectively, but these
elements do  not appear to be taken up in significant
amounts directly  from the water nor are they ac-
cumulated  by food  organisms  (Foster, 1961).   The
failure  of routine  laboratory  analyses  to  detect
these radionuclides in the  whitefish indicates that
they can have concentration factors of no greater than
10.

                  CONCLUSIONS

   The  uptake of radionuclides by fish is a function
of a number  of  interacting factors, which results in
wide  variability.   This variability is  so great that
a  large number of  samples  collected  over at least
one year's time is necessary in order to determine
the average concentration in the fish and fluctuations
with time  - at least in the  case of radionuclides
with relatively short effective half-lives.*

   Concentration factors  derived on  a theoretical
basis,  which assume a high rate of intake by the fish
throughout the year,  will substantially overestimate
the quantities of radionuclides that will accumulate
in  the  fish.  This  generalization should  hold for
radionuclides with effective half-lives of several weeks
or less in ecological conditions subject to wide varia-
tions between seasons.
                ACKNOWLEDGMENTS
   The fish used in this study were collected by mem-
bers of the Environmental Monitoring group under con-
ditions that of ten required special skill and effort. The
success  of  any  project of this  nature is  heavily
dependent  upon  the quality  and timeliness  of the
radiochemical  analyses  performed  on  the  samples
brought in from the field.  We are deeply grateful to •
Mr.  Fred Holt and the members  of  his Radiological
Analysis  Operation,  and especially to  Mr.  Dave
Argyle, for  providing this  service.  Mrs. Darlene
Moore made a very substantial contribution to this
paper by  organizing the data and converting it into
the useful forms presented.  We  also appreciate the
significant effort applied to the analysis of this data
by Mr. Ray Buschbom  of  the Operations  Research
and Synthesis Operation.
                                             REFERENCES
Davis, J. J., R. W. Perkins, R. F. Palmer, W. C. Han-
son, and J. F. Cline.  1958. Radioactive materials in
aquatic and terrestrial organisms exposed to reactor
effluent water.   Proceedings  2nd  Intern.  Conf. on
Peaceful Uses Atomic  Energy 18: 423 - 428.
Davis, J.J., and R. F. Foster. 1958.  Bioaccumulation
of radioisotopes through aquatic food chains.  Ecology
39:  530-535.
Foster, R.  F. 1946.   Some effects of pile effluent
water  on young chinook salmon and steelhead trout.
USAEC Document HW-7-4759, August 31, 1946.

Foster, R.  F., and J. J. Davis.  1955. The accumula-
tion of  radioactive  substances  in aquatic forms.
Proceedings  1st  Intern.  Conf.   on Peaceful  Uses
Atomic Energy 13: 364-367.

Foster, R. F., R.  L.  Junkins, and  C.  E. Linderoth.
1961.  Waste  control at the Hanfordplutonium produc-
tion plant.  Journal Water Pollution Control Federation
33:  511-529.

Foster, R.  F. 1961. Environmental behavior of chrom-
ium andneptunium. In Proceedings of First Symposium
on  Radioecology  held at Colorado State University,
September  1961.  In press.
Nelson, I. C.  (Editor) 1962.   Evaluation  of radio-
logical conditions in the vicinity of Hanford for  1961.
USAEC Document HW-71999: 1-247.

Olson, P.  A., Jr., and R. F. Foster. 1952. Accumula-
tion of  radioactivity in Columbia River fish in  the
vicinity of  Hanford works.  USAEC Document HW-
23093.
Prosser, C. L., W. Pervinsek, Jane Arnold, G. Svihla,
and P. C.  Tompkins.  1945.  Accumulation and distri-
bution of  radioactive strontium, barium-lanthanum,
fission-mixture  and sodium  in goldfish.   USAEC
Document MDDC-496: 1-39.

Watson, D.  G. 1957. Effect of massive doses of P32
on trout.    In Hanford  Biology  Research - Annual
Report  for  1956.   USAEC  Document  HW-47500:
228-235.

Welander,  A.  D.  1945.   Studies of  the  effects of
roentgen rays on the growth and development of the
embryos  and larvae of  the  chinook salmon (Oncor-
hynous  tschawytscha).   Doctoral  Thesis, Univ.  of
Washington,  pp.  131.
  Effective half-life refers to the time required for a radionuclide deposited in a tissue to be dim/shed by one-half as a result of
  the combined action of radioactive decay and biological elimination.

-------
224
                  THE CONCENTRATION OF RADIONUCLIDES IN AQUATIC ORGANISMS
                                              DISCUSSION
   Dr. Oscar Ravera  supplied the following detail on
his paper: the level of radioactivity was determined
in 50  liters of filtered water.  At the present time
only few data on the radioactivity of sediments in Lake
Maggiore are available.

   In the discussion it was mentioned that an increase
in beta  activity  with depth was also found in Lake
Michigan.

   Concerning the disposition of radioactive wastes in
the sea, it was suggested that deposition sites should
be  greater  than 2500 feet deep to prevent our food
organisms from  having direct access to them. This
suggestion  does  not  advocate,  however,  unlimited
disposal of radioactive wastes in the sea, even though
the thermocline  acts  as a barrier to the distribution
of radioactivity introduced.

   As an example of distribution of radioactivity, some
data obtained in connection with the testing of weapons
in the 1958  series were reported:  2 days  after con-
tamination of the area, 50 percent of the radioactivity
in the plankton was tungsten-185, and 50  percent of
that was associated  with  the  silica in the plankton,
mainly  in diatoms.  Examination of the same sample
of plankton 3 weeks later showed a very high tungsten-
185  content  of  the  water, but  the plankton  was
practically free of this nuclide.

   It was stressed that the age and physiological state
of the organism are most important for comparative
studies of uptake of radioactive elements.
   One  explanation  of  the  mechanism of uptake of
radioactive  elements was that the early uptake is al-
most 100 percent surface adsorption, i.e., physical in
nature,  and that later selective uptake and intake play
the dominant role.

   The  isotope dilution concept, or specific activity
approach, may not be applied to fresh water as it is
applied to  sea  water;  the  results  are  consistent
only in the latter.

   It was pointed out that the uptake of phosphorus-32
and  probably other nuclides by live algae is many
times higher than the uptake by dead algae. Uptake is
also different, and often manyf old higher, under natural
conditions  than in  cultures.  Thus, only  ecological
studies picture the real uptake.
   Radionuclides may be returned  to the water when
the organisms containing them are killed.

   The potential effect on people of radioactive uptake
by  algae  blooms  appears  to be small  and of short
duration.    Fishes,  not algae,  are a large potential
source  of radioactive material  in the diet of people,
unless one drinks  unfiltered raw water.
   When the effects of  strontium-90 or cesium-137
are  evaluated, specific activity criteria should be used
rather  than  measurements of absolute  activities.

   The  level of radionuclides, especially phosphorus,
in the blood of fish was not determined in Dr. Foster's
work, but he stated that such determinations have been
made by some of his colleagues.

-------
                      INFORMAL  DISCUSSION SESSIONS

                         BIOLOGICAL INDICATORS OF POLLUTION
                                ALGAE AS INDICATORS OF POLLUTION
                                             Ruth Patrick*
   Since the beginning of the twentieth century there
have been numerous publications  on algae as indi-
cators  of pollution.  In this paper I will refer only
to some of the literature that  has described various
methods or  approaches in using  algae for this pur-
pose.  In the  early part of the century most workers
used the word "pollution" to refer to the presence of
an  organic  load,  which mainly  resulted  from  the
entrance  of  sanitary  wastes  into a river.  Since
this type of  pollution generally  contained similar
types  of chemical  compounds  it  was reasonable
to  suppose  that one  might discover  species that
would  indicate various stages in the assimilation of
these wastes by a river.

   One of the most important, if not the  most im-
portant,  papers  concerned  with  species indicating
stages  of  pollution was the one of Kolkwitz and
Marsson  (1908).   They classified organisms  in or-
ganically polluted rivers according  to the condition
of  the  river  area in  which they were  found. Five
zones  or conditions of a river's organic load were
recognized.   The polysaprobic zone was character-
ized by  a wealth  of high-molecular,  decomposable
organic  matter.   Chemicals  were  usually present
in a reduced  state and little if any dissolved oxygen
was present.  The "<-mesosaprobic zone  represented
the stage in  the  recovery of a river  from heavy
organic  pollution  in which complex organic matter
was present  but  oxidation was  proceeding.  The
/3-mesosaprobic zone  was that in which most of  the
organic  matter  had been  mineralized.  The  oligo-
saprobic  zone was the zone  of cleaner  water  in
which  mineralization  had  been  completed.   The
katarobic zone  was   that of  the clean, unpolluted
water  often found  in  mountain streams.   Each of
these zones or conditions contains species  belonging
to  all  major  groups of algae found in fresh water,
the bluegreens,greens, anddiatoms.    The presence
of  the  species belonging to a  given condition,  for
example "°C-mesosaprobic,n indicated that this con-
dition  existed.  Many workers  such as Hentschel
(1925),  Naumann  (1925, 1932),  Butcher (1947), and
Liebmann (1951) used this system.   They became
aware   that  species  classified as characteristic
of a zone of pollution  often did not occur when such
a  condition  was  present,  or  might be  found under
very  different river conditions  (Liebmann  1942,
Thomas  1944).

   This  lack  of  applicability was  due to several
things.   One was the realization,  as  Butcher  (1947)
stated,  that species of algae  are often  resistant to
pollution rather  than grow well  because of  sub-
stances found in pollution.  Thus these species may
be  found in  many other  river  conditions besides
those to which they were assigned by Kolkwitz and
M,irsson. Another important reason why their system
failed  was  that  pollution had  changed so   much
since the early part  of  the century.  It then mainly
referred to an  organic  load  of  a particular  type;
today it  is a collective noun referring to conditions
resulting from the inflow of many kinds of  chemi-
cals,  some of which are very toxic; various physical
conditions  such as hot water;  and various kinds of
organic  materials  coming from many industrial
sources as well as sanitary wastes.

   Thus, owing to the complexity of pollution, it be-
came  more  and  more  difficult  to  state that any
one  species   might  characteristically be found in
all  kinds of  pollution or  be  generally indicative
of pollution. Wuhrmann (1951),  Sramek-Husek(1956),
and Fjerdingstad (1960) increased the number of zones
characteristic of stages  of   pollution from  the  5
recognized by  Kolkwitz  and Marsson to a total of
15 recognized by Wuhrmann.


   Thienemann  (1939) was  the first  to  emphasize
the fact that certain groups or associations of species
(biocoensis) were  characteristic of a given  type of
environment or biotope.

   He gave the name  "coenobionts" to those species
composing  an association of species characteristic
of a single kind of biotope.  Furthermore, the species
characterizing the association were always found in
large numbers.

   "Coenophile" species  were  those species that
had their best development in a given biotope but
might  be found as part  of the biocoensis of other
biotopes in which they were represented by smaller
populations.

   "Coenoxene" species were those species that did
not seem to be  characteristically associated with
any  particular  biotope  but were found  in  small
numbers in many different biotopes.

   Although Thienemann recognized the  importance
of the association of species in  characterizing ecolo-
gical  conditions, he did not apply  this system to the
algae by listing species belonging to these various
groups.
* Chairman, Department of Limnology, Academy of Natural Sciences of Philadelphia.
                                                  225

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 226
                               BIOLOGICAL INDICATORS OF POLLUTION
   Schroeder  (1939),  Hayren  (1944),  and  Butcher
(1947) were  among the first  to  identify algae as-
sociations with varying degrees of pollution.  Fjerd-
ingstad (1950) recognized in algae communities domi-
nant species, associate species, and accidental species
and  classified these according to the  Kolkwitz and
Marsson system.   He classified the various species
found by determining if they were dominant, associates,
or  accidental occurrences  in  the  various zones or
stages of pollution.  Hustedt (1957) listed species that
indicate heavy pollution if present in large  masses.
forth by  Thienemann  in  1920  and  1939,  that is,
that  the optimum areas are characterized by a large
number of species  with relatively small populations.


   In more recent  studies the general emphasis has
shifted  from  the importance of the mere presence
of certain so-called indicator  species to the con-
sideration of the whole structure of the  algal com-
munity, that is, the kinds of  species, their  relative
abundance  in  the  community, and the total number
of species present.
   Patrick (1949) further emphasized the importance
of considering the structure of the communities of
aquatic organisms including algae.  In these meso-
trophic to  eutrophic  streams, she  considered  as
important the  kinds  of species,  the  sizes  of their
populations, and the numbers  of species composing
the algal communities.  Those algal communities
characteristic of natural or "healthy" areas of streams
in the  Conestoga  Basin were characterized by  a
large number  of  species,  most of which were  re-
presented by  relatively small populations.  These
numbers of species did not change much from season
to season in the same area so long as the ecological
conditions  were  normal  or natural.  Furthermore,
in 1961 Patrick stated that in similar ecological
areas of streams in the same general geographical
areas the numbers of species did  not vary  greatly.
One  of  the first  signs  of pollution was the elimina-
tion  of some  of the more sensitive species and the
development of large populations by some of the more
tolerant species.

   Patrick,  in her various studies, has  produced a
great deal  of  data  that  support  the  principles set
   Patrick  et  al.  (1954,  1956)  working  with the
structure of diatom  populations  came  to  the con-
clusion that the structure of a  natural diatom com-
munity  might be correctly  represented by  a normal
curve  (Figure  1).   The shape of the curve did not
change  greatly  so  long as the environment did not
vary  more  than one would expect from changes in
the natural  environment (Table 1). If the area under
consideration became polluted, the shape of the curve
would  change depending on the amount of pollution.
If  the pollution was  organic in nature and  not very
severe, certain  species  would  be  represented by
very large populations  and thus become  much more
dominant  (Figure  2).   However,  this same  effect
might  result from the  presence of  other  types of
pollution  that  do  not  have  a  very  toxic effect.
Under extreme  conditions resulting from many  dif-
ferent types of pollution, not only do many species
die, which  reduces the  species  number, but those
that remain may have very variable sizes of popu-
lations depending on their ability to resist the particu-
lar pollutant (Figure 3).

   Cholnoky (1958a) developed a method  by which a
change  in the  amount of pollution was indicated by
      UJ
      o
      in
         40
         35
         30
         25
      u-  2o
      CD
         10
                    I
                          I
                               I
                                     I
                                          I
                                                I
                                                     I
                                                           I
                                                               j_
                                                                      I
                                                                           I
                                                                                I
                                                                                      I
                                                                                           I
                                          I
                                                                                                     j
  INDIVIDUALS =   1-2  2"4   4-8  8-16  16-32  32-64   64-   128"  256"  512-  1024" 2048-4096- 8192-16384-32768-
                                                 128  256   512   1024  2048 4096 8192  16384 32768 65536
  INTERVALS =01     2     3    4567    8     9    1 0    I)    12    13    14    15    16
                     Figure 1. The structure of a natural diatom community, Ridley Creek, Pennsylvania.

-------
                                      Algae as Indicators of Pollution
                                                                                                     227
             Table 1.  SUMMARY OF CATHERWOOD DIATOMETER READINGS AT STATION 1 -
                          SAVANNAH RIVER (OCTOBER 1953 TO JANUARY 1958)
Date
Oct. 1953
Jan. 1954
Apr. 1954
July 1954
Oct. 1954
Jan. 1955
Apr. 1955
July 1955
Oct. 1955
Jan. 1956
Apr. 1956
July 1956
Oct. 1956
Jan. 1957
Apr. 1957
July 1957
Oct. 1957
Jan. 1958
(Apr. 1954 to :
averages)
Specimen
number in
modal interval
4 to 8
4 to 8
2 to 4
2 to 4
4 to 8
4 to 8
2 to 4
2 to 4
2 to 4
2 to 4
4 to 8
2 to 4
2 to 4
2 to 4
2 to 4
4 to 8
2 to 4
2 to 4
958 —
Species
in
mode
22
19
24
23
21
19
25
20
27
30
35
24
23
29
21
29
25
27
24
Observed
species
150
151
169
153
142
132
165
132
171
185
215
147
149
177
132
181
157
152
151
Species in
theoretical
universe
178
181
200
193
168
166
221
180
253
229
252
185
206
233
185
203
232
212
194
changes  in  the  percent  of  dominance of  certain
species,  such as  species of  the  genus Nitzschia
(Figure 4).  Cholnoky (personal communication) stated
that  the general ecological conditions in the stream
he studied  did  not  vary much throughout the year.
                                                      Patrick (in  press) stated this may be  possible  if
                                                      the  environmental characteristics remain relatively
                                                      constant  or  if one knows all other  environmental
                                                      factors influencing diatom growth, but that one usually
                                                      does not have this much information;  furthermore,
      o
      UJ
      en
                                                i     i	I  °   I  ,  I	T'0  T 0 "I  „' T
            	  _      _                                                              J
INDIVIDUALS =   1-2  2-4   4~8  8-16  16-32 32'64  64'  128-  256"  5l2- 1024-  2048-4096-  8192-16384-32768-
IINUIVIUUHL-O                                     ,„„   oc^   eio   IMJI  ,,„„„  /,^r>^ 0,^0  IS384 32768 65536
  INTERVALS =0    I     2     3     4    5     6    7     8    9    10    11    12    13    14    15    16


             Figure 2. The structure of a diatom community in a moderately polluted environment, Nobs Creek, Maryland.

-------
228
BIOLOGICAL INDICATORS OF POLLUTION
     o
        40   r
         35
         30
         25
     O  2°
     LJ
     m
         15
         10
          0
                    I
                          I
                                                                            i-°-|- -.--I	I--.--I--0  I
  INDIVIDUALS^   1-2   2'4   4'8   8-16  16-32 32~64  64-  128"  256'  512-  1024-  2048-4096-  8192-16384-32768-
                                                  128   256   512   1024  2048  40968192  163843276865536
  INTERVALS =01     2     3     456     7     8     9    I O    11    12    13   14    15   16

              Figure 3.  The structure of a diatom community in a severely polluted environment. Back River, Maryland.
        Achnanthes minutissima
        Nitzschia spp.
       Azi dobiont e n
                        8a,8b
Figure 4. Changes in the dominance of certain diatoms because of
             pollution (after Cholnoky, 1958a).
                         there may be considerable change  in  the dominant
                         species owing to  factors  of  environment other than
                         changes  in  the  pollution  load.   However,  the total
                         percent  of  the  population  composed  of dominant
                         species, rather than the population size of any given
                         species, is a valuable criterion for judging the effect
                         of pollution.
                                                           The  use of changes in sizes of populations of one
                                                        or a  few species might be more possible if one were
                                                        dealing with  a group  such as fresh-water bryozoa
                                                        or oligochaete worms in which the numbers of species
                                                        that might live in a given area are smaller and thus
                                                        the species change would not be as great with small
                                                        changes of the enviornment,  because species  com-
                                                        petition is much  less.  This does not alter the fact,
                                                        however, that natural changes in the environment may
                                                        bring about the exclusion of a species.
                            Hentschel  (1925), in pointing out the difficulties
                         in using indicator  species  of animals, emphasized
                         the fact that characteristics  of  the  natural environ-
                         ment  may be  very similar to those in a moderately
                         polluted environment.  He also pointed out that con-
                         ditions  in  the natural  environment may limit the
                         development of a  species in similar  ways as pol-
                         lution, and  as a  result, changes  in abundance of a
                         species may not  be related  to changes  in pollution.
                         He  stated that, although  certain  strains  of a species
                         may  be  resistant or sensitive to  pollution,  other
                         strains  may  behave  in quite a  different manner.
                         Butcher  (1947),  Hustedt  (1957),  and   others  have
                         pointed  out that  very few, if any, diatoms are char-
                         acteristic of  a given kind  of pollution,  but rather
                         that some diatoms are tolerant or resistant to many
                         kinds  of pollution and thus  occur in polluted  zones
                         where most species are absent.

-------
                                      Algae as Indicators of Pollution
                                               229
   Cholnoky  (1960)  stated  that  one must know a
great deal about the general physiology of the dia-
tom before he can state that it is  characteristic of
a  given  chemical condition in water.   He  came to
the conclusion that Hornung (1959) stated: That the
total  conductivity of the medium in which a diatom
lives  is  often  more  important than  a  given ion
such  as  chloride in determining the presence of a
given species.
   The kinds of algae species that  are indicators of
pollution  have been designated by  many  workers.
Species characteristic of four major stages or con-
ditions  encountered in the  assimilation of organic
wastes  have  been  recognized.  These have been
discussed by workers such as Kolkwitz and Marsson
(1908), Schroeder (1939), Kolkwitz  (1950),  Liebmann
(1951), Hustedt (1957),  Hornung  (1959), Fjerdingstad
(1950, 1960), and  Cholnoky (1958a,b).
   Other workers  have reported various algae that
they  have  found  to  be  characteristic of various
degrees  of  pollution  caused by  industrial wastes
or  a  mixture  of industrial  and sanitary wastes.
Butcher  (1955) reported Chlorococcum sp. grows well
in the presence of fairly high copper concentrations.
Schroeder   (1939) reported Stigeoclonium  tenue  as
being sensitive  to 0.8 milligram of  copper per liter
of  water,  whereas  Fragilaria  virescens, Synedra
ulna,  Achnanthes affinis,  Neidium bisulcatum,  Navi-
culaviridula, Cymbella naviculiformis, C.ventricosa,
Gompfionema  parvulum,  and  Nitzschia  palea  were
found to live in 1.5 milligrams  of copper  per liter.
Two milligrams of copper per liter was tolerated by
Achnanthes affinis, Cymbella ventricosa,a.nANitzschia
palea.  Corbella et al. (1958) found  that Achnanthes
nodosa was  very tolerant to copper and  ammonia.
Jones  (1958) found  that  in lead  concentrations of
0.4 to  0.5  mg/1  the only common  algae  were Ba -
trachospermum  andLemaneamammellosa.
   Schroeder  (1939)  found the following diatoms  at
pH  3.6 to 4, and with an Fe 2C>3 concentration of 5.7
mg/1:  Eunotia  exigua, E. trinacria,  and Navicula
subtilissima.   In flowing water  with a fairly  high
Fe (OH 3 ) content were Mougeotia,  Ulothrix  tenera,
Gallionella ferruginea, Leptothrix ochracea, Eunotia
exigua,  E.  lunaris, E.  trinacria, Pinnularia   sub-
capitata var. hilseana, and Surirella linearis.
tant to chromium and other pollutants: Stigeoclonium
tenue,  Tetraspora sp.,  Closterium   aceorsum,
Nitzschia palea, Nitzschia linearis, Navicula atomus,
Navicula cuspidata,  Euglenia sociabilis,  E. viridis,
E. acus, E. oxzuris, E.  stellata.   Patrick  (report
onUSPHS grant, 1960)found0.2 to 0.4 mg of chromium
per liter toxic to Novicula seminulum var. hustedtii.
   In a series  of  experiments  carried out in the
Limnology Department of the  Academy of Natural
Sciences   (USPHS  grant),  Navicula  seminulum
var. hustedtii was  found to have the following sensi-
tivities to various  chemicals.   The  concentrations
that caused  50 percent reduction in the amount of
division  occurring  in 5  days  in laboratory  tests
are  as follows:  Cyanide,  0.28 to 0.49 mg/1; soluble
zinc,  1.3 to  4.05  mg/1;  phenol, 251 to 261 mg/1;
and  naphthenic acid, 28 to 79 mg/1. Variation in the
concentrations of a given chemical was due to dif-
ferent hardness of water and different temperatures
under which the tests were conducted.
   Kolbe  (1932) stated that Achnanthes minutissima
and Gomphonema olivacuum often develop large pop-
ulations  that  are associated with  large amounts of
calcium  carbonate.    Cholnoky (1958a) considered
Achnanthes  minutissima  as   indicative  of  a con-
siderable amount of  oxygen  in the water.  Palmer
(1960) gave  a list of genera of bluegreens that are
characteristic  of  water high  in nitrogen and  low in
calcium.
   In summarizing  the  results  of  research in this
field, it is apparent  that  certain  species  of blue-
green  algae,  red algae, green  algae,  and diatoms
may be useful  in  qualitatively indicating  certain
chemical  and physical  conditions of the water as
they relate  to  pollution  and  that most of these
species are  tolerant  to various types of pollution
rather  than indigenous to them.  The  most reliable
method in considering  algae as indicators of pollution
is to study the algal community as  a whole and con-
sider  the  kinds of species, relative  sizes of the
populations of the various  species, and numbers of
species.  Furthermore,  if one wants to compare the
algal flora in various areas  it is necessary to base
conclusions on similar segments of the algae com-
munity.
   Schroeder  (1939) also  found  that  many green
algae  are more sensitive than diatoms are to H 2 S.
Stigeoclonium tenue  could  not  tolerate  a concen-
tration  of 0.2  mg/1,  whereas  Achnanthes  affinis,
Cymbella ventricosa,     Hantzschia amphioxys, and
Nitzschia palea  could  tolerate H 2 S concentrations
of 3.9 mg/1; Cyclotella  meneghiniana, Neidium bisul-
catum, Navicula minima, Nitzschia ignorata,  N.  try-
blionella var. debilis and Surirella ovata var. sabina
could tolerate H 2 S concentrations of 1.5 to 3.7 mg/1.
Blum (1957) reported the following  algae  as  resis-
   When using names to describe a  condition char-
acterized  by  many  kinds of data  one arbitrarily
limits many continual gradients  of conditions.  Thus
it  is  impossible to  describe  briefly a  condition
by any name  such  as n<-mesosprobic,"  and have
it  be infallible.  For this reason, in 1949 I adopted
such  terms as "healthy" and  "semi-healthy,"  "pol-
luted, " and "very polluted" to  connote the variability
one  might expect in  the  organisms and  conditions
present, and  yet indicate a  degree  of degradation
that had taken place.

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230
                               BIOLOGICAL INDICATORS OF POLLUTION
                                             REFERENCES
Blum,  J.L. 1957.  An  ecological study of the algae
of  the  Saline  River,  Michigan.  — Hydrobiologia,
9(4): 361-407.

Butcher,  R.W.  1947.   Studies  in  the  ecology  of
rivers.    VII.   The  algae  of organically  enriched
waters. -- Jour. Ecol., 35: 186-191.

Butcher,  R.W.  1955.   Relation between the biology
and the  polluted condition  of the Trent.  —  Verh.
Internat. Ver. Theoret.  Angew. Limnol., 12: 823-827.

Cholnoky, B.J.  1958a.  Beitrag zu den Diatomeenas-
soziationen des Sumpfes Olifantsvlei  siidwestlich Jo-
hannesburg.  —  Ber. Deutschen Bot. Gesell.,  71(4):
177-187.

Cholnoky, B.J.  1958b.  Hydrobiologische Untersuch-
ungen in Transvaal II.   Selbstreinigung im Jukskei-
Crocodile  Flusssystem. —  Hydrobiologia,  11(3/4):
205-266.
Cholnoky, B.J.  1960.  The relationship between algae
and the chemistry of natural waters. — Counc. Sci.
Industr,  Res. Reprint  R. W. No. 129, pp.  215-225.
Corbella,  C.,  V.  Tonolli,   & L. Tonolli.  1958.   I
sedimenti  del lago d'Orta,  testimoni di una disas-
torsa polluzione cupro-ammoniacale.   — Mem. 1st.
Ital. Idrobiol. "Dott.  Marco De Marchi" Pallanza  ,
10: 9-50.
Fjerdingstad, E.  1950.   The microfauna of the river
M^lleaa;  With  special  reference to the relation of
the benthal  algae  to  pollution.  — Folia  Limnol.
Scandinavica, No. 5, 123 pp.

Fjerdingstad,  E.  1960.   Forurening  af vandl^b bio-
logisk bedjzfmt.   --Reprint from:  Nordisk Hygienisk
Tidskrift, 41: 149-196.
Hayren,  E. 1944.   Studier over saprob strandvege-
tation och flora i nagra Kuststader  i sodra Finland.
—  Bidrag  till  Kannedom   af  Finlands Natur och
Folk, 88(5), 120 pp.
Hentschel, E. 1925.  Abwasserbiologie.  — Abder-
halden's  Handb. d. Biol. Arbeitsmethoden,  Abt.  9,
Teil 2, 1 Hafte, pp. 233-280.
Hornung, H. 1959. Floristisch-okologischeUntersuch-
ungen an der Echaz unter  besonderer Beriicksich-
tigung der Verunreinigung durch Abwasser. — Arch.
f. Hydrobiol., 55(1): 52-126.
Hustedt,  F.  1957.   Die Diatomeenflora des Fluss-
systems  der  Weser im Gebiet der Hansestadt Bre-
men.  — Abh. Naturw.  Ver. Bremen, 34(3): 181-440.
Jones,  J.R.E. 1958.   A further  study of the zinc-
polluted river Ystwyth. — Jour. Anim. Ecol., 27(1):
1-14.
Kolbe,  R.W.  1932.   Grundlinien  einer allgemeinen
Okologie  der Diatomeen. — Ergebn. d. Biol., Band
8, pp. 221-348.

Kolkwitz,  R.  1950.    Okologie der  Saprobien.  —
Schriftenr.  Ver.  f.  Boden  u.  Lufthygiene, No.  4,
64pp.
Kolkwitz,  R.  & M. Marsson.  1908.  Okologie der
pflanzlichen  Saprobien.  —  Ber.  Deutschen  Bot.
Gesell., 26a:505-519.

Liebmann,  H. 1942. Uber den Einfluss der Verkrau-
tung auf der  Selbstreinigungsvorgang  in  der Salle
unterhalb Hof. -- Vom Wasser, 15:92-102.

Liebmann,  H. 1951.  Hnadbuch der Frischwasser -
und Abwasser-biologie. — Miinchen: Verlag R. Old-
enbourg. Vol. 1, 539 pp.
Naumann, E. 1925. Die Arbeitsmethoden der region-
alen Limnologie.  — Abderhalden's Handb.  d. Biol.
Arbeitsmethoden.  Siisswasserbiologie. 1.

Naumann, E.  1932.  GrundzUge der regionalen Lim-
nologie.   —   Bennengewasser, Band 11, 176  pp.
Palmer,  C.M. 1960.  Algae and other interference
organisms  in  the waters of the South Central United
States.  —  Jour. American  Wat. Wks. Assoc., 52:
897-914.
Patrick,  Ruth.  1949.  A proposed biological mea-
sure of stream  conditions, based on a survey of the
Conestoga Basin, Lancaster County, Pennsylvania —
Proc.  Acad.  Nat.  Sci. Philadelphia, 101:277-341.
Patrick,  R.  1961.   A study of the numbers and kinds
of species  found in rivers in eastern United States.
—  Proc. Acad. Nat. Sci. Philadelphia, 113(10):215-
258.

Patrick,  Ruth,  (in press).   A discussion of natural
and abnormal diatom communities.  — Nato Advance
Study  Institute  —  Algae and Man.   July,  1962.

Patrick,  Ruth, M.H. Hohn, and J.H. Wallace.  1954.
A new  method  for determining the  pattern of the
diatom flora.   —   Not. Nat., Acad. Nat. Sci. Phila-
delphia, No. 259, 12 pp.

Patrick,  Ruth and M.H. Hohn.   1956.  The diatom-
eter —  a method  for indicating  the condition of
aquatic life.    —  Proc. American Petroleum Inst.,
Sect. 3, 36: 332-338.

Schroeder,  H.  1939.   Die  Algenflora der  Mulde;
Bin Beitrag zur Biologie saprober Flusse. — Pflan-
zenforschung, Heft 21, 88 pp.
Sramek-Husek,  R.  1956.  Zur biologischen Charak-
teristik  der   hoheren  Saprobitatsstufen.  —  Arch.
Hydrobiol., 51:376-390.

Thienemann,   A.  1920.   Untersuchungen liber die
Beziehungen zwischen dem Sauerstoffgehalt des Was-
sers und der  Zusammensetzung der Fauna in nord-
deutschen Seen.  — Arch. Hydrobiol., 12:1-65.

Thienemann,  A. 1939.  Grundziige einer allgemeinen
Okologie. — Arch. f. Hydrobiol., 35:267-285.

Thomas, E.A. 1944.  Versuche liber die Selbstrein-
igung fliessenden  Wassers.  — Mitt.  Gebiet Leben-
smitt.   —   Untersuch. u.  Hyg.,  35:199-228.  Bern.

Wuhrmann, K.  1951, Uber  die biologische  Prlifung
von  Abwasserreinigungsanlagen —  Ges.-Ing.,  72.

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                                     Algae as Indicators of Pollution
                                               231
                                              DISCUSSION
   A  question  arose whether  the definition of the
word "pollution"  should  be based  on  the  present
economic  or practical use of the water.   It was
noted, however,  that we  ordinarily assume a large
degree  of the water  usage will be  in the future,
and,  therefore, care  must be exercised to account
for the condition of the bodies of all water.


   In considering  the  advantages  of  a  biological
index of  pollution  over  a chemical one, it was
brought out  that chemicals ordinarily have a more
rapid response to changes than the algae.  Although
the chemist  is able to tell what  specific  chemicals
are present  at a  given  time,  he might often miss
things.  The  biological method will at least indicate
that something has happened and  give  you  an  over-
all picture.  In reality, the two indices complement
each other.


   It  was  noted that classifying pollution according
to zones  or  organisms is  fashionable in  Europe,
but it was suggested that perhaps the workers in
the United States are not completely  familiar with
this type  of  classification.  Although pollution may
occur in many types and kinds of streams and some
people are ever trying to apply the indicator organism
concept to lakes, one cannot really compare a mountain
stream  with  a river such as the Ohio.  Therefore,
it is  impossible  to use any  particular organism or
group of  organisms  as pollution indicators for all
of the many types  of  aquatic communities.  Also,
there appears  to be a  great deal  of  disagreement
among authors about the  use of  teminology in pol-
lution studies.

   The  number of kinds  of algae considered to be
pollution tolerant is generally quite limited for any
one area  or survey but becomes large when all of
the results  of many investigators are combined.
When a compilation was made of the  reports of 110
workers, a total  of more than 50 genera were listed
as  being  tolerant  to  sewage or related conditions.
The genera Euglena and Oscillatoria, however, were
listed as  the most tolerant by over 50 percent of the
workers.   In closing this  area of  discussion, it was
suggested  that we are working too hard with  com-
plex systems and  calculations, and, in  reality,  a
good biologist  can merely look at a  stream and get
a good idea of its condition.


   It was  pointed  out  that  there  is  a fundamental
difference in  a community having a  few species
and one having many.

   A question arose  whether there  is  a  quan-
titative  relationship between a biological index and
the  organic  material  present in a stream.  An
example was  given of a  river  having a relatively
low  pH and  also being polluted.   An  examination
of the  species  present can readily tell  you whether
you  have  pollution or  not, by  whether  there are
acid-loving species  present  or   pollution-tolerant
species present.

   Again  the  question  was   raised  whether
anything but the dominant group  is  significant (in
a microphyte community).  In answer to this it was
stated  that all  species, whether  dominant or  not,
can  tell you whether a  condition is toxic  or not.

   In controlling  algae in reservoirs and ponds,
the  engineers   try to  control  nutrients  affecting
the growth of  algae and  at present are trying to
control  the phosphate  content.   The question  was
asked if  phosphate control is effective in control-
ling algal growth.  It  was pointed  out that there are
many nutrients  involved and  it would  be of  little
value to  control the  phosphate  without controlling
the nitrogen.   It was  also mentioned that the algae
that are   considered  to  be  the  worst  odor pro-
ducers  do not require  much phosphate.

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 232
        BIOLOGICAL INDICATORS OF POLLUTION
                             SOME REMARKS ON A NEW SAPROBIC SYSTEM

                                            E. Fjerdingstad*
   At the Second Seminar on  "Biological Problems
in Water Pollution" held  in Cincinnati in 1959, Pro-
fessor Erman A.  Pearson gave a very interesting
survey of the antagonism between the estimation of
pollution  by  engineers and  by biologists.   In  his
search for  a quantitative method for biological  as-
says  of  the waters, he  went  on to say that "there
should be  a  minimum core of biological measure-
ments that  would suit every situation just as there
is with  respect  to physical and chemical assays."

   Professor Pearson also proposed a working scheme
for estimation of  pollution containing  the  following
biological items:    (1)  Coliform; (2) phytoplankton;
(3) zooplankton; (4)  fish;  (5) Biomass; and (6) identi-
fication and  enumeration  of genus and species of or-
ganisms, whose numbers  are equal  to  or more than
10 percent of total population.

   From the point of view of biologists, these demands
are very great and time consuming and would neces-
sitate the participation of several specialists.   Be-
sides, exact determination of the biocoenosis  of ses-
sile  microorganisms  would  hardly  be possible at
present  in  practical work.  Therefore, the  method
could only be used to determine the planktonic popu-
lation numerically.

   THE MATHEMATICAL  METHOD OF REPORTING
                   BIOTIC DATA

   In some papers published  in recent years, authors
converted the biological estimation  of  pollution  into
numerical  values   (Pantle  and Buck,  1955; Beck,
1955;  Knopp,  1954).   They  were  forgetting that
biological  communities  are  complex  systems  and
cannot be reduced  to exact  numerical  values to be
entered  into  neat  columns alongside the analytical
results.
   It  is a common feature of these systems that the
individual  species is given  a qualitative numerical
value depending  on the saprobic zone  to which the
species belongs and a numerical value representing
the estimated quantities in which it occurs.

   Pantle and Buck thus  use the following numerical
values for the qualitative evaluation of the saprobic
zone ("s") —  1 = oligosaprobic; 2 =/3-mesosaprobic;
3  = c* -mesosaprobic; and  4 = polysaprobic.   The
estimated  quantitative  evaluation "h" is denoted as
follows — 1 = occurring incidentally;  3 = occurring
frequently;  and 5  = occurring  abundantly.  For  this
purpose  a  mean saprobical  index  "S"  is calculated
for each locality.
                    S =
Ssh
Sh
   The  authors  give the following  numerical values
for the  individual  zones:    1.0 to 1.5 denotes the
oligosaprobic zone; 1.5 to 2.5 denotes they?-mesosa-
probic zone; 2.5 to 3.5 denotes the «<-mesosaprobic
zone;  and  3.5 to 4  denotes  the polysaprobic zone.

   Mathematical  manipulations that  are  based  on
the numerical values ascribed to the individual species
are far from exact because the different ecological
valencies of the species actually argue against the
application of an exact mathematical interpretation.
Even  if the other  objections were  disregarded it is
obvious that these values cannot tell anything about
the polysaprobic zone, which  is particularly char-
acterized by the great differences between maximum
and minimum load.

   Some authors (Gaspers and  Schulz, 1960; Bring-
mann and  Kiihn,  1960)  repudiate  the  mathematical
methods as does the present author.

   DEPENDENCE OF THE MICROCOMMUNITIES
           ON BIOCHEMICAL FACTORS


   Many of the organisms occurring in the  polluted
waters are able to utilize a great variety of nutrients.
For others the choice is  limited  since they are
dependent upon the presence of specific substances.

   The interactions  among  different species (due to
extracellular  substances) occurring at a locality is
probably of great importance  in the composition of
the local community of organisms.

   Vitamins also seem to  be essential to the growth
of algae; e.g.,Euglena gracilis requires thiamine and,
in addition, vitamin 612 to produce optimum growth.

   Hutner,  et al.  (1956) state that it  may  prove to
be  as  important  to  account  for the contents  of
certain vitamins and other  organic compounds as to
measure temperature, concentrations of nutrient salts,
and other "classic variables."


   As the  algal  population changes with the decreas-
ing pollution of a receiving water, it must be  said that
by  considering  solely  the  inorganic  salts,  as has
hitherto  been done,  it  is impossible  to appreciate
the causal principle.

   The  requirement that the biological estimation of
pollution should be correlated with chemical factors
cannot be  fulfilled  at present, for routine chemical
analyses  can only illustrate  an  approximate  rela-
tionship.
  Institute of Hygiene, University of Copenhagen, Copenhagen, Denmark.

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                                 Some Remarks on a New Saprobic System
                                               233
            A NEW SAPROBIC SYSTEM

   Kolkwitz and  Marsson's  saprobic  system (1908)
gave a list of indicator species for biological esti-
mation of pollution. Indicator species are not partic-
ularly suitable for determining the zones of pollution,
however, because the adaptation possibilities  of a
species have, as a rule, very wide ecological limits.
For this reason a species will often occur in several
saprobic zones.

   It is  clear, however, that the  optimal conditions
for the presence of  a species are generally very
closely  delimited in contrast to the ecological limits
of its possible occurrence.  This suggested that the
community-forming organisms might form the basis
of the estimation since community formation must
be analogous to the optimal  living conditions of the
species.  In this case, however, it is essential to
distinguish sharply between the  autecological (the
single  species)  and the synecological  (community)
aspects.  For only by doing so will it be possible to
obtain a further development of the saprobic system.

   As to the  autecological designation  of the  rela-
tionship  of an organism to pollution, the author has
chosen these  designations:

saprobiontic:  species that occur  (in large numbers)
              only in heavily polluted waters.
saprophilous:  organisms that occur generally in pol-
              luted waters but may  occur  also in
              other   communities; i.e.,  organisms
              that  to a   certain extent are  indif-
              ferent.
saproxenous:  organisms that occur generally in bio-
              topes  other  than   polluted ones  but
              may survive even in  the presence of
              pollution.
saprophobous: organisms  that  will  not survive  in
              polluted waters.

   In this system the  relationship of each particular
species  to pollution  will allow for  a better under-
standing than the traditional division  corresponding
to the appurtenant saprobic zones will.
   As to the  pollutional zones, we have hitherto had
too few,  a situation  felt  to be  of importance es-
pecially  in the  polysaprobic zone where there are_
such considerable and decisive differences between,
for instance, the last  and  the first part of the zone.
Finally,  Kolkwitz and Marsson's system  contains
no  zone  for  the undiluted  faecal  water in  which
oxidation and mineralization have not begun.
   The  strictly  delimited  zone for  undiluted faecal
water is  named the  coprozoic zone.   Moreover, a
distinction is made between an < -polysaprobic, a
^-polysaprobic, and  a  /-polysaprobic zone;  an
°<--mesosaprobic, a-^ -mesosaprobic, and a  kath-
arobic zone; there are altogether nine zones.

   By extending the  zone  number to nine, increased
possibilities  are achieved with regard to indicating
the amount of pollution.  Consequently, for the nine
zones there  is  a corresponding  series of  micro-
organism communities (Table 1).
 Table 1. SURVEY OF THE SAPROBIC ZONES AND
       THE CORRESPONDING COMMUNITIES

 Zone I. Coprozoic zone

         a: the bacterium community
         b: the Bodo community
         c: both communities

 Zone n. "* -polysaprobic zone

         1: Euglena community
         2: Rhodo-Thio bacterium community
         3: pure Chlorobacterium community
 Zone III.B-polysaprobic zone

         1: Beggiatoa community
         2: Thiothrix nivea community
         3: Euglena community
 Zone IV. Y -polysaprobic zone

         1: Oscillatoria chlorina  community
         2: Sphaerotilus natans communities

 Zone V. ^ -mesosaprobic zone

         a: Ulothrix zonata community
         b: Oscillatoria benthonicum community
           (Oscillatoria brevis, O. limosa, O.
           splendida with O. subtilissima, O. princeps,
           and O. tennis present as associate species)
         c: Stigeoclonium  tenue community

 Zone VI./3-mesosaprobic zone

         a: Cladophora fracta community
         b: Phormidium community

 Zone VII.y- mesosaprobic zone
         a: Rhodophyce community (Batrachospermum
           moniliforme or Lemanea fluviatilis)
         b: Chlorophyce community (Cladophora
           glomerata or Ulothrix zonata (clean-water
           type)

 Zone VIII. Oligosaprobic zone

         a: Chlorophyce community (Draparnaldia
           glomerata)
         b: pure Meridian circulare community
         c: Rhodophyce community (Lemanea an-
           nulata, Batrachospermum vagum or
           Hildenbrandia rivularis)
         d: Vaucheria sessilis community
         e: Phormidium inundatum community

 Zone IX. Katharobic zone

         a: Chlorophyce community (Chlorotylium
           cataractum and Draparnaldia
           plumosa)
         b: Rhodophyce community (Hildenbrandia
           rivularis)
         c: lime-incrusting algal  communities
           (Chamaesiphon polonius and various
           Calothrix species)

Legend:  a, b,  c — as alternatives
         1, 2,  3 -- as differences in degree

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 234
                                BIOLOGICAL INDICATORS OF POLLUTION
  CHEMICAL REASONS FOR THE ZONE DIVISION
   With  some  reservations because  of the above-
mentioned shortcomings of the chemical analyses of
sewage  to  characterize  the  zones  of a  saprobic
system,  there  may be  said  to exist,  however,  a
certain  chemical  basis   for  the  saprobic system
developed  by the author.    By  neglecting  extreme
analytical  values  that  may be  considered the  re-
sult of some failure or  other,  e.g., metallic poi-
sons,  very large precipitations, or sudden thawing
of  snow  that  greatly dilutes the  sewage, a better
agreement may  be obtained between  the chemical
analyses and the  biological division into the author's
nine zones.
   On the basis of a considerable number of analyses,
Figures 1 through 4 represent graphically the average
course  of some  chemical actions in  the zones as
well as maximum and minimum values.
    ZSOO mg/{ 3.O.D (fobc/j)
    1000
     100
      /O
               mix..

                                        N.
    Zones  J   JT  H  -ZT   Y   XT  m  EBT 2Z
                                                                 mg/l.
                                       H2 5
                                                           Zones    I      JT      M     IZ      I
Figure 2. Diagram representing maximum and minimum values of
        hydrogen sulphide content in Zones I to V.
                                                             $0 mg/l
                                                                                               Total N
                                                            lanes I
                                                           Figure 3. Diagram representing maximum, minimum, and mean
                                                                  values of total nitrogen content.
                                    AT/4 -N
                                    N03-N
                                                            lones I   JT  M   IX  T   JL  M  JUT  JZ
  Figure 1. Diagram representing maximum, minimum, and mean
          values of BOD determinations.
  Figure 4.  Diagram representing maximum, minimum, and mean
          values of ammonia nitrogen and nitrate nitrogen.

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                                  The Significance of Macroinvertebrates
                                                                                                       235
       POLLUTION BY INORGANIC MATTER

   Each  type of  industrial waste  containing inor-
ganic  substances  has its special  "appearance* and
its  communities,   depending on the type  and extent
of the compounds in the effluent (especially poten-
tially toxic substances).   All  that  can be  done at
present  with  this  type  of industrial  waste is  to
distinguish  between  Zone  I, the  chemotoxic zone,
and  Zone II, the chemobiontic  zone.  In the former,
no organisms occur because of the amount of toxic
substances; in the latter, some  organisms are found.
                                              REFERENCES
Beck, W. M. 1955.  Suggested method for reporting
biotic  data.   Sew.  & Ind. Wastes.  27: 1193-1197.

Bringmann, G., and Kiihn, R. 1960.  Kartierung der
Wassergute  nach  dem  Biomassentiter-Verfahren.
Gesundheitsing. 77: 23-24.

Gaspers,  H.,  and  Schulz,  H.  1960.   Studien zur
Wertung der Saprobiensysteme.  Int. Rev. Hydrobiol.
45: 535-565.

Fjerdingstad, E, 1950.  The microflora of the River
Mjzflleaa, with  special references to the relation  of
the benthal algae  to  pollution.   Folia Limnologica
Scand. 5: 1-123.

Fjerdingstad, E.  1956.   Bacteriological  investiga-
tions  of mine  water from lignite pits  in Denmark.
Schweiz. Zeitschr. Hydrologie. 18: 215-238.

Fjerdingstad, E.  1962.   Pollution of streams  esti-
mated by biological methods  (In press).
Hutner, S. H., Provasoli,  L., MacLaughlin, J. J. A.,
and  Pintner,  I. J.  1956.   Biochemical geography.
Some aspects  of  recent vitamin research.  Geogr.
Rev. 46: 404-407.

Knopp,  H. 1954.   Bin  neuer  Weg zur Darstellung
biologischer  Vorfluter  Untersuchungen.   Wasser-
wirtschaft. 45: 1.

Kolkwitz  and  Marsson.   1908.   Okologie der pflan-
zlichen Saprobien,  Berichte Deutsch. Bot.  Gess.
26a: 505-519.

Pantle, R., and Buck,  H. 1955.   Die biologische
Uberwachung der Gewasser und die Darstellung der
Ergebnisse. Gas-und Wasserfach, 96: 604.

Pearson,  E. A. 1959.   What does the sanitary engi-
neer expect of the biologists in the solution of water
pollution  problems.   Tech. Report W60-3, Robert
A.  Taft Sanitary  Engineering  Center, U.S. Public
Health Service, Cincinnati, Ohio, pp  139-144.
       THE SIGNIFICANCE OF MACROINVERTEBRATES IN THE STUDY OF MILD RIVER POLLUTION

                                              H.B.N. Hynes*
   I have the  impression, after  reading  the trans-
actions of the first two  seminars  in  this  series,
that perhaps  the  last word on biological indicators
of pollution  has  been  written.   It also seems that
either nobody  quite  knows  just  what is meant by
pollution  or  everybody  means something different.
Doudoroif and  Warren (1957), in particular, stressed
that if, by pollution, is meant  damage to fisheries,
it is only rational  to study fishes;  if deterioration
in the usefulness of water for some other  purpose
is  meant, one should  study  the water  from  that
particular viewpoint. This is sound sense, but it can,
I submit, be carried too far. One  could, for instance,
ask  the  chemists why they measure BOD,  Their
object in doing so  is, fundamentally, to determine the
effect  of the effluent on oxygen concentration in the
receiving water,  so why  not  measure only that?  I
think a chemist might reply that  it was easier and
more  informative  to  work  with  BOD,  since  it
is less liable to  be disturbed  by extrinsic  factors.
I feel that  the biologist can also say that, at least
initially,  small organisms are  easier  and more
satisfactory to work  with  than  fish  since they are
relatively simple  to sample and they do not move
around very  much.   If  they show  signs of alteration.
it may be worth  going on to see  if the alteration
also applies to other properties  of the water, such
as  its ability  to  support fish or  its usefulness for
water supply.  If  no  great alteration is found in the
invertebrates,  it  seems  reasonable to assume that
none  has in fact occurred to other characteristics
of  the  river.   I can  imagine no type of pollution
that would  make  water  unsuitable for industrial,
domestic, agricultural, or fishery purposes  without
having some detectable effect on the flora and fauna.
Perhaps radioactivity could do this, although I doubt
it;  anyway,  it  would be a strange organization that
sent  out  only  a  biologist to look for radioactive
pollution if it were suspected.
   I agree  that pollution  is  not a  word with any
absolute meaning and that each case  must be looked
at by itself, taking all sorts of factors into account;
I do not subscribe  to the school of thought, to which
Doudoroff  and  Warren  relegate  Dr.  Patrick, that
considers any alteration to the  biota as pollution,
although that  is in fact a reasonable  interpretation
of the  common law  in both Great  Britain  and the
United  States.  I do  believe, however, that study of
fauna and flora is a  very useful and rapid tool in the
investigation  of pollution.   It  can also  be  a very
delicate one,  but like all such instruments  it  must
be used with care, intelligence, and skill.
  Department of Zoology, University of Liverpool, England.

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236
                                BIOLOGICAL INDICATORS OF POLLUTION
   Liebmann (1951,  1961)  is the great contemporary
exponent of the idea first advanced by Kolkwitz and
Marsson  (see  Kolkwitz,  1950, for a  recent exposi-
tion)  that  microorganisms  can be used to indicate
organic pollution.   This is certainly true,  although
I would not agree with the details of their zonation,
which seem altogether too theoretical, and  which
have often been shown not to apply to particular cases.
Despite difficulties of technique and identification that
arise in the use of  microorganisms   (Lackey, 1957),
and  the  fact  that  most  of them must  be studied
alive, they do offer a means of detecting,  and to
some  extent of quantifying, fairly heavy concentra-
tions of organic  matter,  although they are not as
useful for  other types of pollution.   Patrick  (1957)
advocates  the  use  of  diatoms, which do not  suffer
from  some of  the disadvantages  of other  small
organisms.  These small plants  may prove to be
extremely useful, although I would suggest that it is
dangerous to confine a  study  to  just one group of
organisms  when  dealing  with the whole  range of
possible pollutants.   To cite two examples from my
own field  of work, it is  well known that stoneflies
are   eliminated  by  very   low  dosages of  organic
matter and so  are often taken  to  indicate well-
oxygenated  water   suitable for fish; but  they are
unaffected by  concentrations of heavy metals  that
are   quite  lethal to  fish (Jones, 1940 a  and b.).
Similarly, the  sludge  worms Tubifex and Limnod-
rilus thrive in organically polluted  water  but are
killed by small amounts of heavy metals.

   Gaufin  (1957)  has  given a  general account of
the  occurrence  of  aquatic  insects  in relation to
organic enrichment; the  main principles of the use
of these  and other invertebrates as indicators of
organic pollution are  now well understood.   It is
clear, however, that further work on basic biological
problems  will enhance our  understanding.   Thus,
for  instance,  my  colleague  Dr. R.O. Brinkhurst,
in a study of  the rather  neglected tubificid worms,
found that  the specific  composition and the  pro-
portion of the  species  present change as one passes
from severe to  less severe  organic pollution.   I
believe that further knowledge of  the Chironomidae
also  might  make  the  larger  invertebrates more
useful as indicators in heavily polluted water.  Par-
ticularly  in this zone of heavy  organic pollution
is so much similarity found among the  fauna in
widely separated  parts of the world.  Thus, Tubi-
fex,  Limnodrilus, and Chironomus species are re-
ported in polluted areas as far  apart as Java (Vaas
and  Sachlan,  1955), South Africa (Allanson,  1961),
Europe (Hynes, 1960),  and  North America  (Gaufin
and Tarzwell, 1956).

   Nevertheless,   even under conditions of  fairly
heavy enrichment,  there  can be no  rigid rules, be-
cause regions  differ in their fauna, and rivers and
effluents  differ from one another.   To ask,  as did
Pearson (1960), that biologists should produce quan-
titative data that are universally applicable is like
crying for  the moon.   He seems to have been un-
fortunate  in his encounters  with  biologists in that
some  of  them appear to  have  been  very  narrow-
minded,  some  very  readily  overwhelmed by  dif-
ficulties,  and  others overenthusiastic and unaware
that  vast numbers  of  measurements lead only to
indigestible piles of data.  Here I agree with Doudo-
roff  and Warren  that, if much time and  effort is
to be  spent in investigations,  one should measure
only what one wants to know.

   The  macroinvertebrate  survey, which  is  rela-
tively  quick and  easy to  make,  tells  one if it is
worth  investigating  further.  Since it is based on no
hard and fast  system, it is  flexible  and allows the
investigator  to look  afresh at each problem and
interpret  the data in the  light of prevailing  cir-
cumstances,   I would go so far as to say that this
sort of interpretation is  also necessary  for strictly
numerical  chemical and physical data because rivers
vary in  their  susceptibility  to  pollution.   A  load
of organic matter that would be damaging in a trout
stream may be quite acceptable in a sluggish base-
level river simply because the inhabitants of rapid,
cool streams  are  very  sensitive to diminution of
dissolved oxygen  and to silting,  whereas  those of
sluggish warm  streams are  much less so.  Similarly,
salmonid  fishes  seem to be  more sensitive  to  a
wide  range  of poisons  than  are fishes of  other
families.   Thus, I maintain that even the numerical
data of the  chemists are  not the strictly  quanti-
tative parameters of pollution that they  seem  to be
at first sight.

   The  larger  invertebrates have, in a sense, "es-
caped" from inclusion in the Kolkwitz and  Marsson
Sabrobiensystem,  largely  because very few  were
mentioned  in the original papers,  and many of  those
that were included were misidentified --a fault that
Hebmann  has  done  little to correct.  So, although
some European workers  (e.g., Huet, 1949) have pro-
duced  lists  of animals said to  be  characteristic
of  certain  levels of  pollution,  macroinvertebrates
have not  become deeply involved  in the  doctrine.
Many of them, however, show clear reactions to
organic pollution.  It  is also well established  (Car-
penter, 1924; Pentelow and Butcher,  1938) that they
react to poisons and simple salts (Liebmann,  1951;
Lafleur,  1954),  so  there  is a reasonable chance
that  they can serve to detect all kinds of pollution.
Simple  surveys  of  the  invertebrates  have,  as  I
hope to  show,  great  sensitivity, especially if they
are quantitative; I know that they give useful results
in Britain  (Hynes,  1961b; Hynes and  Roberts,  1962)
and in Africa  (Hynes and Williams, 1962).  I believe,
therefore,  they  can  be useful anywhere, but the
interpretation  of  results  does require  biological
knowledge.   In a  subject as complex as  ecology, I
do not see how  that can ever be avoided.

   It is  well known that unaltered "natural" rivers
have a definite type  of  fauna.   Details vary from
one region to another, but  in general the same sort
of life  forms  recur  even  though, as lilies  (1961)
has  recently shown,  similar forms may have been
evolved by widely differing  organisms in  different
continents.   It is also well established that, as one
goes down  a river from source to base level, one
passes  through a sequence of  more or less  well-
defined  zones, each  with  its  characteristic but
broadly similar  fauna (lilies,  1955;  Schmitz,  1957;
Hynes,  1961a).  It  is clear, therefore, that slight

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                                   The Significance of Macroinvertebrates
                                                                                                           237
changes in water hardness, silt deposition, oxygen
regime, and  so on,  induce slight faunlstic changes.
These changes affect different creatures at different
levels, and initially  involve only alterations  in rel-
ative abundance.   In Europe and doubtlessly in North
America,  for instance, there is a  decline in  the
importance of  Plecoptera and  an increase in  the
importance of  Ephemeroptera  as  one  goes down-
stream.

   We  can use  the  method that served  us in dis-
covering  this  sort  of  thing  to  detect  the  obverse
changes in rivers that are  altered by man.  This
can  be done simply  and quickly, and is  a very valu-
able  first source of information since  it shows  if a
particular effluent is in fact  causing an alteration,
how  far that  alteration extends,  and whether it is
becoming  more or  less  marked.   It does  not  and
cannot indicate  whether fish are affected or whether
water is altered  for  industrial use any more than
can  routine  chemical analysis of a  mildly polluting
effluent,  but  if  it  reveals little change in the in-
vertebrate fauna,  it is reasonable  to  assume  that
the effects are not adverse. Similarly, if the change
leaves a fairly normal river  fauna,  albeit different
from the one that was  there before, it is reasonable
to assume that some  types  of fish, at  least, will
thrive  and that the water  is still usable, although
      perhaps  not for  the  same   purposes as  before.
      Here once  more  we come  hard up against the ques-
      tion of what we mean  by pollution.  The degree of
      alteration that can be permitted is a matter of ad-
      ministration at a high level.
         If one  collects  a series  of  samples of inverte-
      brates  at points spaced along  a river, changes  in
      fauna  are  readily  observed.   Collections must be
      quantitative and  from the  same  sort of substratum
      at  each point, but  how  they  are made  can vary ac-
      cording to circumstances.   Ideally,  areal samples
      with a  sampler like that of Surber  can be used, and
      they  are  worthwhile   if  great accuracy is  needed
      as well as an estimation of confidence limits. Usually,
      a  simple  collection with a hand  net plied  in a fixed
      manner for a fixed time suffices. If the water is too
      deep for  wading, the technical problems are greater,
      but  various  grabs  and  dredges  can  be used.  All
      types  of  samplers are  selective  to  some extent
      (Macan,  1958; Hynes,  1961a),  but  the collections
      should  be comparable if the  same methods are  used
      at all stations; they only cease to be so if there are
      marked changes  in rate  of  flow below the  outfall.

         Figure  1  graphically shows  the  results  of  four
      surveys of  a Welsh river when it was recovering
      from pollution by a chemical works  whose  effluent
                     Lumbriculidae
                        Erpobdella
                        Crangonyx
                        Gammarus
                       Ecdyonurus
                       Heptagenia
                       Rhithrogena
                           Boetis
                           Caenis
                         Perlodes
                          Isoperla
                          Leuctra
                      Amphinemura
                      Hydropsyche
                      Rhyacophila
                       Glossosoma
                     Orthocladiinae
                    Ceratopogonidae
                           Helmis
                           Esolus
                         Latelmis
                                    JAN 1956
APR 1957
MAR 1958
FEB 1959
       Figure 1. The percentage composition of the principal members of the fauna of a British river in 4 successive years. The
               river flows from left to right in each set of histograms.  The 12 stations, shown juxtaposed, were 1.3, 0.4, and
               0.2 miles above the outfoll from a chemical works, shown by dotted lines, and 0.2, 0.6, 1.1, 2.6, 4.7, 5.9, 7.8,
               10.2, and 16.0 miles below it. At each station, the vertical height of each histogram is proportional to the per-
               centage of the total number of specimens caught at that station. The figure is based on the following total
               numbers: 1,987, 1956; 10,805, 1957; 3,487, 1958;  and 3,836, 1959.

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238
BIOLOGICAL INDICATORS OF POLLUTION
contained various organic compounds, mostly phen-
olic.   The  factory  had installed a modern and ef-
fective  treatment plant,  which was  still being im-
proved  during  1955,  1956,  and early 1957.   The
histograms  show the percentages of the  total fauna
collected  at each station;  only the  more  common
animals  are shown.  The stations were spaced at
increasing distances from the outfall, three above
(1.3,  0.4, and  0.2  miles) and nine below  (0.2, 0.6,
1,1, 2.6, 4.7, 5.9, 7.8,  10.2, 16.0 miles); a standard
10-  or  15-minute collection was made with a hand
net  at  each station.   The  time spent varied with
the river level;  in  1956 and 1959, the tests took 15
minutes because the level was high,  and in 1957 and
1958  they  took  10  minutes because  the level was
relatively low.   The  collections at  0.2 mile below
the outfall were made  on the  left  side of the river,
in the path of  the effluent, since the effluent did not
become fully mixed  until some distance downstream.

   In 1956,  the  effluent was having a fairly marked
effect on a number of animals: many were absent
from the first station below the outfall;  even some
that were  present  (e.g., Ecdyonurus and Perlodes)
were almost  certainly strays, perhaps from  the
opposite bank, since they were  absent from several
stations  downstream.   Most   notably,  the Ecdyo-
nuridae (Heptageniidae),  Plecoptera,  and Helmidae
were absent for some  distance, but  Baetts, mostly
the species rhodani, was reduced in importance only
below the  outfall.  In North  America a species of
Callibaetis  has  been recorded as occurring in or-
ganically polluted water (Gaufin and  Tarzwell, 1956)
and  (that) Baetis harrisoni has been reported from
midly  polluted  water  in South  Africa  (Harrison,
1958).  Thus, the presence of  Baetidae is no indica-
tion of  clean water.  Although we are dealing with a
chemical effluent here, its earlier effects were similar
to those of  organic  matter, e.g., lowering of oxygen
content and   encouragement  of  Sphaerotilus and
Chironomus.

   In 1956,  scattered growths of sewage fungus were
still  present.   By  1957,  Sphaerotilus  was  found
at the first two stations below the outfall only after
careful  search,  several  animals  were  still absent
from the  first  station,  and Baetis  still showed  a
marked reduction in importance.   The  only other
faunistic change  that seems to have been associated
with the effluent was that Ceratopogonidae (probably
a  species of Bezzia) was  encouraged.   The figure
shows no  changes  in  1958  and  1959 that can be
ascribed to the  effluent.   Thus, the river had re-
turned to normal, and this process was  easily fol-
lowed by  simple  faunistic surveys.   It is my con-
tention  that, in  1957, the presence  of the effluent
could not  have  been biologically demonstrated in any
other manner;  this  even  applies to the presence of
Sphaerotilus, which  can usually be  found  if  it is
specially sought, even in clean rivers.

   Other differences between  the  surveys are ap-
parent.    Baetis  rhodani  was clearly much  more
important in 1957 and 1958 than in the other years.
Very  probably,  this  is  because  of the  different
months in which the  surveys were made. The samples
taken in March  and  April  had  large numbers, which
                        probably was caused  by a wintertime hatch of rest-
                        ing eggs.   A similar  explanation probably applies to
                        the relative unimportance of Rhithrogena  (mostly
                        semicolorata)  in the  stations  above  the  outfall in
                        1956.    Further,  there  was a  tendency  in all years
                        for the  Ecdyonuridae  to be absent or less abundant
                        at the first  station upstream of  the outfall.  This
                        was, I believe, caused  by  a small, dirty stream and
                        a  small  sewage  works  effluent  that  entered the
                        river  above this  station.  Neither produced  any
                        obvious effect,  such as sewage fungus or diminution
                        of oxygen, but they did contain suspended solids and
                        so, presumably, rendered  the  substratum less suit-
                        able for flat mayfly nymphs.  For other variations
                        and irregularities  (e.g.,  by Lumbriculidae), I can
                        offer  no tentative  explanation,  but  it does seem that
                        Latelmis  volkmari was  more  common at the lower
                        stations in all years.   Probably,  with  more inten-
                        sive sampling  to  reduce  random  error and  more
                        knowledge  of the ecology of the organisms involved,
                        satisfactory explanations would be forthcoming.

                           So  far,  we have considered  only relatively mobile
                        creatures  that  can readily  reestablish themselves
                        as soon as conditions become  suitable.   The limpet
                        (Ancylastrum fluviatile)  is  far  less  mobile   and
                        is best  recorded separately because it is less easily
                        taken  by  net.   In  1956, this mollusk was only found
                        at and  below  5.9 miles  from the outfall; in 1957,
                        it had moved upstream to 4.7  miles; in 1958, it was
                        present at 1.1 miles;  and, in 1959, it  was found at
                        all stations.  This animal, therefore, showed the
                        same  general  effects  as the other  invertebrates,
                        except that its  recovery  was  more delayed.  The
                        alga Lemanea (Sacheria) presented a rather similar
                        picture  by being  quite  absent below the outfall in
                        1956 and  1957, present at 2 miles and below in 1958
                        and 1959, but more common there in the latter year.
                        These relatively sessile organisms  are, therefore,
                        very sensitive indicators of past pollution, and they
                        take a long while to return.

                           My second example  concerns a paper mill that
                        complainants had  accused of causing growths of
                        sewage  fungus.   I was asked  to report on the  state
                        of the river,  but it  was during July 1960 when the
                        mill had been closed for 2 weeks and all the Sphaero -
                        tilus  was  gone; only scattered debris  remained in
                        the river  bed.  Samples were  collected in the same
                        manner as before, but were  much less thoroughly
                        worked  in that the animals were not counted but were
                        recorded on a simple scale  (P = 1 or 2 specimens;
                        F,  about  5; C,  about  25, A,  about  100; V, several
                        hundred).   The stations were above the outfall, and
                        50  to 100 yards,  200 to 300 yards,  about 1/2 mile,
                        and 1  mile below  the outfall.  The results, given in
                        Table 1,  clearly  show that in July 1960, conditions
                        were  not  normal at the first two stations below the
                        outfall,  as shown by the changes in the numbers of
                        Leuctra, Helmis,  Esolus,  Hydracarina, and Ancyl-
                        astrum,  and had  been more  severe at  50 to 100
                        yards  than 200  to 300 yards  below the  outfall as
                        shown by  the  changes in the numbers  of  Baetis
                        and Ephemerella.   A  similar study conducted in
                        March confirmed  that  sewage  fungus grew only in
                        the first  3 to  400 yards  below the outfall and that
                        it formed a  complete carpet for only about  200

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                                  The Significance of Macroinvertebrates
                                              239
         Table 1. THE OCCURRENCE OF CERTAIN ANIMALS IN SAMPLES FROM A BRITISH RIVER
                             RECEIVING EFFLUENT FROM A PAPER WORKS
Macro-
invertebrates
Nais
Erpobdella
Gammarus
Baetis
Ephemerella
Ecdyonurus
Rhithrogena
Leuctra
Amphinemura
Isoperla
Hydropsyche
Rhyacophila
Helmis
E solus
Tanypodinae
Orthocladiinae
Chironominae
Hydracarina
Ancylastrum
July 1960
Samples a
12345
CbF C C F
P P
P P
V C V V V
V C V V V
F P P

F P F F




C P C C
C FCC
C A C C C
V V A V V
F P F F C
F F P
A A V
Mar. 1961
Samples
1234
A A V A
P P P
P F
A P A A

F C
C C
F P F
A F C
F PC
C P F
C P F
F P P
F P F P
P C P P
C A A A
C C
P P P
A PA
July 1961
Samples
12345
V
P P P
P P F F
V F V V V
V F V V V
F P F F

A C C C



P F F F
F F F P
F F C F
A V C A A
A V C A A
F A C F F
P F F P
V C V V V
           a Station 1 was above the outfall; 2, 50-100 yd below the outfall; 3, 200-300 yd below; 4, 1/2
             mile below; and 5, 1 mile below.  b P equals 1 or 2 specimens; F, about 5; C, about 25;
             A, about 100; and V, several hundred, in 10-minute collections made with  a hand net.
yards.  At that  season, other invertebrates that are
absent in the summer were  missing from stations
2 and 3 (e.g., Rhithrogena) or missing from station
2  and  reduced   in  importance  at  station 3  (e.g.,
Amphinemura,  Isoperla,  Hydropsyche, and Rhyaco-
phila).  By the following  summer, a treatment plant
had  been  installed;  sewage  fungus was  rare  and
only to be found at the  first station below the ef-
fluent  when  carefully  sought.    Several  creatures
still  showed  signs  of the effects  of the effluent,
however,  although often  only quantitatively.  Thus,
Gammarus,  Ecdyonurus,  Rhyacophila, and  Helmidae
were  not  found;  Baetis,  Ephemerella,  and Ancyl-
astrum  were relatively less common; and Nais  and
Chironomidae were more common at station  2  than
elsewhere.
   This example  shows that  a very simple study of
the  invertebrates  can be  used  to determine  the
extent of pollution, even when it is no longer oc-
curring  (1960),  and to check on recovery while it
is being abated.  Both of the simple investigations
outlined  gave  positive  results  when  the  levels
of pollution were so slight that there  was no other
evidence that damage  to other  interests, such  as
fishery or  water supply, was occurring.  Complaints
concerned only the presence of drifting sewage fungus
that  was  entangling fishermen's  lines; even  these
referred only to the first year in both investigations,
and would very possibly not have been made except
that  earlier  both  rivers had been much  more  ser-
iously polluted.

   My  thesis  is   then, that study of the  macroin-
vertebrates  is a useful tool  in the detection of very
mild pollution, that the study enables possible danger
spots to be located and recovery to be closely fol-
lowed,  and  that it  retains its  sensitivity down  to
levels  at which most other methods of study  cease
to be useful.  I would also emphasize that the ex-
amples  I have given  are  of extremely simple, al-
most crude, investigations. More thorough sampling
and  mathematical  treatment would,  I  imagine, in-
crease  the  sensitivity even more.   Mathematical
approaches  to this  type  of data  have been  dis-
cussed by Allanson (1961), Gaufin et al.  (1956), and
Patrick et al. (1954).   It  may  be that this line of
inquiry  merits further study; but, as I hope I have
shown, even very  simple methods can detect pollu-
tion  so  mild that it scarcely merits the name under
any  definition.  In short, although I have  worked
in other  continents and other latitudes from those
in which Beck has worked, I find myself in complete
agreement with almost everything he said at the first
of these symposia  (Beck, 1957).

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240
          BIOLOGICAL INDICATORS OF POLLUTION
                                             REFERENCES
Allanson,  B.R.  1961. The  physical,  chemical and
biological conditions  in the  Jukskei-Crocodile River
system.  Hydrobiologia 18: 1-76.

Beck,  W.M.  1957.  The  use  and abuse of indicator
organisms.    Biological  Problems  in  Water Pol-
lution. U.S. Pub. Hlth. Serv. Cincinnati. 175-7.

Carpenter, K.E.  1924. A  study of the fauna of rivers
polluted  by lead  mining  in th Aberystwyth District
of Cardiganshire. Ann. Appl. Biol. 9: 1-23.

Doudoroff, P., and Warren,  C.E.  1957.  Biological
indices of water pollution, with special  reference
to fish populations.  Biological  Problems in Water
Pollution.  U.S. Pub. Hlth. Serv. Cincinnati. 144-163.

Gaufin, A.R.  1957.   The use and value  of aquatic
insects as indicators of  organic enrichment, ibid.
136-40.

Gaufin, A.R., and Tarzwell,  C.M. 1956.  Aquatic
macroinvertebrate communities as indicators of pol-
lution  in  Lytle  Creek.   Sewage  Ind. Wastes  28:
906-24.

Gaufin, A.R., Harris, E.K., and Walter, H.J. 1956.
A statistical  evaluation of  stream  bottom sampling
data obtained  from three  standard samples. Ecology
37: 643-8.

Harrison,  A.D.   1958.  The effects of organic pol-
lution  on  the fauna of parts of the Great Berg River
system and of  the  Kron Stream.   Tras.  R. Soc. S.
Africa 35: 299-329.

Haet,  M. 1949.   La pollution des  eaux.  L'analyse
biologique des eaux  polluees.   Bull.  Centr. Belg.
Etude Doc. Eaux  5 & 6: 1-31.
Hynes, H.B.N.  1960.
Liverpool.
The biology of polluted waters.
Hynes,  H.B.N. 1961a.  The invertebrate fauna of a
Welsh mountain  stream.   Arch.   Hydrobiol.   57:
344-88.

Hynes, N.B.N. 1961b. The effect of sheep-dip containing
the insecticide BHC on the fauna of a small stream,
including  Simulium  and its predators.  Ann. Trop.
Med. Parasitol. 55: 192-6.

Hynes, H.B.N., and  Roberts, F.W. 1962.   The bio-
logical  effects of synthetic detergents in the River
Lee,  Hertfordshire.   Ann. appl. Biol. (in the press).

Hynes, H.B.N., and  Williams, T.R.  1982.  The ef-
fect of DDT on the fauna of a Central African stream.
Ann. trop. Med. Parasit. (in the press).

lilies, J. 1955.  Der biologische Aspekt der limno-
logischen  Fliesswassertypisierung.  Arch.  Hydro-
biol. Suppl. 22: 337-46.
lilies,  J. 1961.  Gebirgsbache in Europa und in Suda-
merika - ein limnologischer Vergleich.  Verh.  int.
Ver. Limnol. 14: 517-23.


Jones, J.R.E.  1940a.   The fauna of the River Mel-
indwr, a lead-polluted tributary of the River Rheidol
in north Cardiganshire,  Wales.   J. Anim. Ecol. 9:
188-201.


Jones, J.R.E.  1940b.   A study of the  zinc-polluted
river Ystwyth in north Cardiganshire,  Wales. Ann.
appl. Biol. 27: 368-78.

Kolkwitz, R.  1950. Oekologie der Saprobien.  Uber
die  Beziehungen der  Wasserorganismen  zur Um-
welt. Schr. Reihe Ver. Wasserhyg. 4: 1-64.

Lackey,  J.B. 1957.  Protozoa as indicators  of the
ecological condition of  a body of water.   Biological
Problems in Water Pollution.  U.S. Publ. Hlth. Serv.
Cincinnati 50-9.

Lafleur, R.A.  1954.  Biological  indices of pollution
as observed  in  Louisiana streams. Bull. La. Engng
Exp. Sta. 43:  1-7.

Liebmann,  H.  1951.  Handbuch   der  Frischwasser
und Abwasserbiologie. Munich.

Liebmann,  H.  1961.  Handbuch   der  Frischwasser
und Abwasserbiologie Band II. Munich.


Macan, T.T.  1958.   Methods of sampling the bot-
tom fauna  in  stony streams.  Mitt. int. Ver. Lim-
nol. 8: 1-21.

Patrick, R.  1957.  Diatoms as indicators of  changes
in environmental  conditions.  Biological Problems
in  Water Pollution.    U.S.  Publ. Hlth.  Serv. Cin-
cinnati. 71-83.
Patrick, R., Hohn,  M.H. and Wallace,  J.H. 1954.
A new method  for  determining  the pattern  of the
diatom flora.  Not. Nat. Acad. Sci. Philadelphia. 259:
12pp.

Pearson, E.A.  1960.  What  does the sanitary engi-
neer expect  of the biologist in the  solution of water
pollution problems?  Biological  Problems in Water
Pollution U.S. Publ. Hlth.  Serv. Cincinnati. 139-44.

Pentelow, F.T.K., and Butcher, R.W. 1938.   Obser-
vations on the condition of Rivers Churnet and Dove
in 1938.  Rep.  Trent Fish. Dist. App. 1. Nottingham.

Schmitz, W.  1957.   Die Bergbach-Zoozonosen und
ihre Abgrenzung, dargestellt am Beispiel der oberen
Fulda. Arch. Hydrobiol. 53:  465-98.

Vass K.F., and Sachlan,  1955. Cultivation of common
carp in  running water  in  West  Java  Proc. Indo-
Pacific Fish  Council  6: 187-96.   F.A.O. Bangkok.

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                                  The Significance of Macroinvertebrates
                                              241
                                              DISCUSSION
   Dr. D.D. Stone of Manitoba described the results
of a study by the Manitoba Fisheries Section  of the
Pollution  of Lake Winnepeg by the Red River.  Pol-
lution sources are communities and industries along
the Red River.   The Red River valley above the lake
is a  great beet- and potato-producing area.   Pol-
lutional effects were described as mild. Lake Win-
nepeg is located above the city of Winnepeg.

   Dr. Jack Dendy of Alabama Polytechnic Institute,
Auburn,  Alabama,  described  how wastes  from in-
secticide  plants  and the runoff  from  agricultural
areas sprayed with  insecticides suddenly killed fish
in streams and  reservoirs in Alabama.  He  asked
how  one  would go  about  evaluating effects of pol-
lution of  this  type.  Dr. Hynes described methods
used in Great Britain of  collecting as many species
as possible during a given time.   Dr. Ruth Patrick
suggested  using  species  diversity and numbers of
individuals as was  done in a survey of the Sacra-
mento  River,  Keswick Reservoir (California),  and
vicinity.   Catherwood diatometers were used in this
survey.

   Paper  chromatography was also mentioned as  a
means of determining the presence of insecticides.

   Mr. T.W. Beak (Ontario, Canada) described how
the effects on the macrofauna had been used to trace
a  source  of pollution in  Lake Superior for 5 or 6
miles.

   Dr. Marcel Huet (Belgium) stated it was  fairly
easy  to   compare  polluted  areas  with unpolluted
areas by  sampling the riffles of a stream above and
below sources of pollution.   The need to present
biological  data by statistical  methods  that can be
understood and analyzed by engineers was discussed.
It  was emphasized  that  biological  results  cannot
always  be  expressed by  mathematical  formulas;
reasonable judgment of  biological effects  is  often
needed.

   Mr. Carlos Fetterolf  (Michigan Water Resources
Commission) believed that, as he  gained experience,
he could  more effectively judge the effects of pol-
lution  by  qualitative rather   than  time-consuming
quantitative work and questioned whether quantitative
data are after  all very meaningful.

   Dr. Hynes  stated that when we investigate pol-
lution, we often only assay some particular quality
of the water such as temperature  effects, the effects
of low oxygen, etc.

   Mr. John Wilson observed that engineers plot sag
curves for streams based on dissolved oxygen, BOD,
probability of low flows,  stream flows, etc., by which
they predict how far downstream damaging effects
may occur during low-flow periods. He recommended
that biologists quantitate  their data in the same way
so that predictions could be  made  on what  would
happen to the  bottom fauna, fish,  etc., downstream.
This would be an oversimplification of an extremely
complex  problem,  however, involving the  influence
on  the  aquatic environment of many  little-known
industrial pollutants.  Although some engineers and
other physical scientists recognize the complexity of
the aquatic  environment, they overlook possible en-
vironmental damage by pollutants, "passing by on the
other  side,"  and  rely solely  on the parameters
mentioned  above —  DO and BOD — for water re-
source planning.  Not until legislation develops will
the biological-environmental approach be considered.

   Dr. Hynes, emphasizing the lack of data on quanti-
tative effects  of pollution,  asked who could say what
biological effects  a  reduction  from   8 to  7  ppm
dissolved oxygen would create.

   Mr.  Surber  expressed  his   conviction that al-
though the  use  of  quantitative  sampling  apparatus
entailed  considerable work, it was justified in deter-
mining not  only present conditions  but also back-
ground data from  which in the future it could be
determined  whether  conditions in  a  stream  had
actually deteriorated or improved.

   Dr. Ruth  Patrick  discussed the  difficulties of
using such terms as "present," "common," "frequent,"
and  "abundant" as quantitative terms;  it is better to
consider groups of organisms  rather than individual
species.

   Dr. Hynes  mentioned that because stoneflies were
early emergers, often appearing during the  winter,
they might be missed in the  count of species present
if the stream were sampled only during the summer.

   The danger of trying to do too  much with one
group of  organisms, such as the  diatoms, was  pointed
out.   Microorganisms are  generally  more  sensitive
than the macroinvertebrates as indicators  of pol-
lution.  On  the other hand, generally, stoneflies are
indicators of  clean  water  and  the  tubificidae  are
indicators of  organic pollution. Dr.  B.R. Allanson
pointed   out the similarities between  the  fauna of
Europe  and that of  South Africa, and the macro-
invertebrates  in South  African trout  streams  and
those in  European trout streams.  He described the
faunal changes that occurred at different elevations
above sea level.

   Dr. Huet showed  histograms -  of the seasonal
abundance of  different types of macroinvertebrates
in streams,  with  some data based  on samples of
macroinvertebrates  collected with  a net during 10-
to 15-minute  periods above and below a source of
pollution.  The  organisms were classed as present
(P),  common   (C), frequent  (F), and  abundant  (A).

   Mr. T.W. Beak stated that the square-foot sam-
pler, if  used in areas of  uniform materials, gives
a  good  measure  of  the  effects of pollution;  that
the number of individuals can  be just as meaning-
ful  as number  of species; and that we should pro-
duce drawings and  illustrations of  biological samp-
lings that  could be  understood  and used by  the en-
gineers.

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242
BIOLOGICAL INDICATORS OF POLLUTION
   Dr.  R.O. Brinkhurst  (University  of  Liverpool,
England) described the great  variation he had found
between different areas in the quantitative sampling
of various bottom organisms,  particularly tubificids.


   Dr. W.  Schmitz emphasized the utility of quanti-
tative  data in delimiting the  zones of pollution in a
stream.   It is  very  important, he said, to collect
chemical  data   concurrently  with  biological  data.


   Mr.  W.M. Beck  of  Florida cautioned  that  the
presence  of tubificids was not always  an indication
of a  polluted stream and humorously reported the
collection in a  healthy stream of an Ekman dredge-
full  of tubificids  due to  the  presence of  a dead
opossum  in the immediate  vicinity.   Mr. Surber
reported circular red colonies of tubificids in small/=
mouthbassbrood-stock ponds  at  a  fish hatchery at
spots where aquatic  vegetation  had been raked into
piles  the preceding fall and left to dry.  The local-
ized abundance of tubificids apparently was due to an
accumulation of putrescible  materials  where  the
vegetation  decayed during overwintering.  He empha-
sized, however, that in  pollution  surveys,  organic
enrichment of habitats was usually characterized by
the presence of tubificids in unusual numbers.

   Dr. W. Rodhe pointed  out the need for investi-
gating the functional  aspects of organisms.  Each
organism   has  a  metabolism of its own and  both
biological  and  chemical  methods  are required  to
determine  the organism's  characteristics.  In lakes,
organisms are  distributed vertically and there are
differences in spatial distribution.  When a lake is
polluted with organic wastes, assimilation and dis-
similation  are going  on.  Plecoptera are  not present
in  streams that have more  assimilation than dis-
similation.


   Dr. Hynes wondered what would happen  to  the
assimilation process  in a stream  if  copper were
suddenly added to the  environment.

   Dr. A.R. Gaufin expressed  the  opinion  that we
should become  more  familiar with the life histories
and habits of aquatic organisms and know what their
requirements are; most  of us  cannot  even identify
our species, let alone know their life histories, etc.
He stated  we are still in  the taxonomic  stage. Dr.
W.D.  Burbanck stated that the number of taxonomists
is diminishing and suggested  that we send materials
for identification to the National Museum; if we take
the total productivity at different trophic levels, we
need to know with what species we are dealing. Dr.
Schmitz called  attention to studies of  the effects of
pollution on the oxygen production of weeds in streams.
Such  stream studies  are  complicated by  the effects
of tributaries.    The  streams of Great Britain are
mostly  of  one  type,  but streams  on  the continent
vary  a great deal.   He recommended that groups
of organisms such as the diatoms be studied by spe-
cialists in that field.
                           Dr. Patrick stressed  the  need for  data on  en-
                        ergetics  and  for  more  information on  succession
                        in the blue-green  algae; the use of artificial sub-
                        strata needs to be perfected.

                           Mr. Beck pointed out that  energy flow techniques
                        in establishing ecosystems require a tremendous a-
                        mount of time. Dr. Hynes described the distribution
                        at high altitudes of organisms some of which cannot
                        endure sediment on the stones upon which they live.
                        Stoneflies,  he  said, are sensitive to lack of oxygen,
                        and mollusks are sensitive to heavy metals.  Tubificids
                        were also described as sensitive to the presence of
                        heavy metals.

                           Dr. Burbanck  inquired whether  we  were all to
                        become   molecular biologists.  The  names of  the
                        genera or species that are indicator organisms should
                        be put to use.

                           Dr. B.R. Allanson stated that South Africans know
                        the species of the more important groups. By hard
                        work, one  can learn  the  species  and often  many
                        of their  requirements.   Aquatic insects,  he said,
                        are most sensitive to pollution or temperature changes
                        during molting stages.

                           Dr. Hynes  described the resistance of insect eggs
                        to pollution and how a Norwegian worker found that
                        insects  fly  upstream  before  depositing their eggs.
                        These eggs are collected with a screen of 120 meshes
                        to the inch.  Dr. Allanson stated that care is needed
                        when  macroinvertebrates are used to  indicate pol-
                        lution; elevation,  temperature, and turbidity can af-
                        fect  their  presence.    Some  groups of  insects  or
                        families  drop out in going  downstream from  the
                        headwaters.  Mild pollution may produce its greatest
                        effects in the  upper reaches of a  stream. Ecological
                        changes such  as changes  in water temperatures, in-
                        crease  in   turbidity,  or  pollution  may have  con-
                        siderable influence proceeding dowstream.

                           Dr. N.W. Britt, of  Ohio State  University,  de-
                        scribed  changes from 1942 to  1962 in the distribution
                        of the burrowing  mayfly Hexagenia limbata, midge-
                        fly larvae, and oligochaetes in Lake Erie. South of
                        Rattlesnake Island on  Lake Erie, Hexagenia limbata
                        decreased from a maximum of 493 per  square meter
                        in 1942,  to  15 per square meter in 1960, and to zero
                        in 1961  and 1962.  As the  Hexagenia  decreased,
                        certain  midgefly larvae and oligochaetes increased;
                        in 1962  when there were  no burrowing mayflies,
                        there were 1,150  midgefly  larvae and 7,825 oligo-
                        chaetes  per square meter in the lake bottom.  No
                        mayflies were found in the deep water of Lake Erie
                        where the  dissolved-oxygen  content was under 0.5
                        ppm.

                           Mr.  John Wilson discussed Dr. Howard Odum's
                        opinion  that  species  diversity  data  are  the  best
                        means of illustrating pollution effects.  He described
                        Dr. Odum's method of counting up to 1,000 organisms
                        in samples  and recording the species diversity with-
                        in this 1,000 group.

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                                   The Significance of Macroinvertebrates
                                               243
                                    Concurrent Informal Discussion
   This  meeting  opened  with Mr. Thomas  Beak,
Chairman, describing some  of the methods he and
other investigators have tried in  using "aquatic or-
ganisms as indicators of water quality."

   Other  ideas came  from  numerous persons  on
methods  used or  contemplated  for  such  studies.
Suggestions  such as  standing crop, extent of species
diversity, and maximum production (e.g., g   fish/
unit  area) were offered to replace or add to the idea
of indicator  species.  The point was made that ap-
parently no  organism is so restricted that it occurs
only in "clean or dirty" water.

   Bioassay  was run up and down the gauntlet.  The
physiological  condition of the test animals and the
time of year were listed as important considerations.
Transplanting  of  algae-protozoa  or macroinverte-
brate groups by transferring multiple-plate samplers
of glass  or  masonite,  respectively, would lend to
laboratory bioassay studies.  In this case necessary
considerations include  the similarity  of the basic
testing  water to the water at the  collection  site.
Studying a pollutant by testing its components  sep-
arately  or in  simple combination was reported  on
favorably by several researchers.

   Several comments were made concerning the limits
of laboratory studies and the necessity of combining
laboratory and field studies to  give a complete
picture.   The relative value of short-term studies
designed  to  get  preliminary, data  and  give quick
answers, and long-term studies where  the complete
analyses  are necessary were discussed.  The im-
portance of  life history studies, including basic eco-
logical relationships, was pointed  out,  especially  as
related  to following the cycling of elements through
an ecosystem.

   Several suggestions  regarding  the methods  of
tackling  pollution  problems were  discussed.  Es-
tablishing a position of "expert biologist," who would
decide the water quality limits allowable, was among
these.  Another  was the  idea of studying specific
organisms in  specific  situations.   Although some
animals  may serve  as pollution  indicators,  many
others will react differently to a pollutant depending
on other  environmental factors.   A third method
involved a threefold  study, including the  usual bio-
logical  and   chemical measurements at the  polluted
site,  and an  investigation  of the  operations at the
industry or source of pollution.
   In describing the  effects of a  polluting agent,
the term  "tolerance" is quite prevalent.  A lengthy
discussion centered around tolerance and its modi-
fiers such  as moderate,  high, or  non-.  From the
comments,  it  seemed agreeable  and advisable to
use  this  term specifically  as  follows:   (e.g.,  "sp.
A is tolerant  of  200 ppm  silt turbidity  for up to
30  hours  before  feeding  ceases"  rather than the
general "sp.  A is  moderately tolerant of silt tur-
bidity").   The comment  was  made that  much data
are now available  in the  literature and in personal
files  that  could be  used to group aquatic  organisms
in relation to their specific tolerances for  specific
substances.

   Several methods  of expressing results were dis-
cussed.   Two types of reports were favored.  One
form was the "slide rule" for the engineers and the
other is designed for the biologically minded reader.
Several investigators gave their opinions of subjective
versus objective reporting.

   Several additional  remarks  came out regarding
the need  for  life history-taxonomy work in pollu-
tion   studies.    Researchers from  Great  Britlan,
Canada, and  half-dozen  states  regarded the lack
of students entering taxonomic  work  as a serious
problem.    Possible  reasons  given  were  lack of
demand,  lack  of favorable  financial support from
sponsoring  agencies,  and  lack of interest among
some college faculties and  administrators.  It  was
pointed  out  that  in North  America,  much of the
toxonomic-type work is done  in the museums, where-
as in Great Britian, for example, taxonomic workers
are  more evenly  dispersed.  One  solution  offered
would have each ecologist take a particular animal
group and work on the requirements or limits of its
individual  member   species,  considering not only
lethal  limits,  but  also  limits  for such  things as
optimum growth, reproduction, etc.

   The  closing ideas were aimed at people who send
specimens to  taxonomists  for identification.   Three
suggestions seemed especially notable:    (1) Supply
adequate  ecological data  with  the  specimens to aid
the taxonomist in the identification and in his per-
sonal knowledge of the species, (2)  expect to pay for
his services, and (3) expect a delay between the time
the specimens are  sent and  the time identifications
are received.

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                                       ORGANIC PESTICIDES

         THEIR DETECTION, MEASUREMENT AND TOXICITY TO AQUATIC LIFE

                          Oliver B. Cope *  and Clarence H. Hoffmann, 1" Chairmen

                                    PESTICIDE-WILDLIFE RELATIONS

                                             Oliver B. Cope
                 INTRODUCTION

   The detection and measurement  of organic pesti-
cides  and their toxicity to  aquatic  life constitute
the fish-pesticide problem.   Researchers primarily
interested  in fish  and pesticides  in nature must,
however,  include the  whole biota  in the scope  of
their interest.

   Studies on pesticides and fish usually begin with
bioassays to  determine acute toxicities of chemicals
to various species of fish.  People working in this
area, once their testing methods are standardized,
are  invariably  intrigued with questions  about the
application of their results to  animals in the field.
This leads to inquiries into the influence of factors
in the environment  on toxicity,  into  what happens
to the pesticide  in the environment  and in  the fish
and  other  animals,  into the nature and importance
of chronic effects, and into many other consequences
of field applications. To study these mechanisms, the
researcher must concern himself with the detection,
measurement, and toxicity of the pesticides.

                   DETECTION

   Detection  and measurement usually  go hand  in
hand, but  there are instances in which detection and
not measurement is accomplished.   Sometimes  this
is because the worker desires only  qualitative infor-
mation, but usually it is either because there are
no quantitative methods available, or because those
available are too time-consuming or require equipment
that is not available.

   A case of detection without regard to measurement
might be the determination of the presence or absence
of enough toxicant  to kill fish following  a fish-
eradication project  in a lake.  Here,  the placing  of
fish  in a live-car  in the  lake gives a measure  of
safety  for planting; this is commonly done by fishery
biologists who do not  desire measurements of the
amount of toxicant in the water.

   A  case of detection with only  semiquantitative
measurements  might  be the  use  of bioassay for
residues  of  herbicides.   Here, where  seeds  are
incubated  in  the presence  of  unknown  amounts  of
herbicide  in  water or  soil,  and  the  inhibition  of
root or stem growth  is compared with  a standard
curve, there is variation in response from  species
to species of seed, and from herbicide to herbicide.
The  establishment of standard curves is sometimes
difficult, and results must often be interpreted semi-
quantitatively.  This is frequently the best that can
be  done,   since  methods  of analysis  by  chemical
techniques have  not  yet  been  devised for  many
herbicides.

                 MEASUREMENT

   Why  do we measure  organic pesticides?   The
pesticide  problem is  complex and  involves inter-
relationships among  the  pesticide, the water, the
animal  in which we  are interested, other animals
in the environment, plants, bottom sediments, and
other substances.  It involves also the dimensions
of time and space.  So, if we are to understand the
total consequence of the pesticide  treatment, we must
study the  chemical  in relation  to the  components
of the  environment.   It  seems necessary,  also,
to understand changes, and here  is where time and
space become so significant. The changes inpesticides
over  periods of  time, under the influence of heat,
light, and chemicals  in  the surroundings,  and  of
microorganisms,  must be measured if we are to know
or predict whether our animals are damaged or helped
by the pesticide.  The effects of space in concentrating
or in diluting the pesticide after it leaves the airplane
or after it reaches the water should be understood.
These effects  can be most efficiently studied by
measurements  of the amounts  of pesticides at times
and places designed to  show how much can be available
to an animal for each time and position in the  habitat.
The  fate of the pesticide, once it enters the animal
body, must also  be studied.  Whether it is stored
or excreted, and whether in  its original form or
in a more  or less toxic form, are things we wish to
know,  and we  must  usually measure  to  find  out.

   Thus,  the   measurement  of  pesticide  quantity
appears to be a vital requirement  in a comprehensive
pesticide-animal program of investigation.

   When embarking on a program of measurement of
organic pesticides in water, in fish, in invertebrates,
in mud,  or in aquatic vegetation, the investigator
must exercise  judgment  in the approach  to the
study.  He must know what analytical  methods are
available  for the particular  chemical  in  question.
* Chief, Fish-Pesticide Res. Lab., U.S. Fish & Wildlife Service, Denver, Colorado.
tAssf. Director, Ent. Res. Div., Plant Ind. Stat., USDA, Beltsville, Maryland.
                                                   245

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246    ORGANIC PESTICIDES THEIR DETECTION, MEASUREMENT AND TOXICITY TO AQUATIC LIFE
He should  also know the cost of analyses if the work
is to be done in a commercial laboratory, and whether
equipment,  knowledge,  and  experience are  locally
available  if the  work  is  to  be done  in his own
laboratory.  The objective of the work and the amount
of precision desired are factors that enter into the
choice of analytical methods. Some knowledge of the
limitations of the various methods is valuable if there
is a  question  of  the need  for measurement of the
original  pesticide, or  of  its  metabolites, or  both.

   What methods are available for measuring organic
pesticides?  Two principal analytical approaches are
used, biological and chemical. Bioassay is the basis
for biological  measurement of  pesticide residues.
Here, a standard dosage-mortality curve for a specific
length of  time  of  exposure  is first established.
Then the  unknown  material  is given  to the test
organism, and the response is referred to the standard
curve  to  learn the  amount of unknown.   With this
method,  a  variety  of  animal species is  used for
insecticide measurements; guppies, houseflies, mos-
quitoes,  and Daphnia are common test animals for
detection  of chemicals  in  water.  Seeds of plants,
such as cucumber, tomato, flax, and corn, are popular
for measurement  of  unknown amounts of herbicides.
Bioassay  has limitations, but  can  be very useful
for detection of pesticides that cannot be measured
by  chemical methods and for  verification of values
that can be measured by the chemist.  It can also be
useful in cases where chemical or physical methods
do not distinguish among toxic and nontoxic metabo-
lites of a pesticide.

   The  measurement of pesticides by  chemical and
physical methods is more widely practice,d than is
bioassay.   A  variety  of  methods  is used in the
chemistry  laboratory;  each has its  advantages and
limitations.

   Photometry, including colorimetric and spectro-
photometric procedures, and gas chromatography are
widely  used for  analysis following  extraction and
purification of the  pesticide.   These methods are
versatile and accurate;  lack of sensitivity has been
their chief  disadvantage. Recently developed detectors
for the gas chromatograph have, however, made this
a powerful  tool for residue analysis.  Another method
coming into wider use is paper chromatography and
color development with suitable reagents.  This is
an  extremely  sensitive procedure,  but  is not yet
as  accurate as instrumental methods.   The short-
comings  of  this  method for  the  determination of
chlorinated  hydrocarbons arise mainly from the lack
of a suitable device for the measurement of the color
of the spots.  Another method involves  the use of
radioisotopes to trace the paths of  chemicals in the
fish and in the environment.  This method is accurate
and  sensitive and can be used with chromatographic
procedures to reveal the breakdown products of pesti-
cides as they change.

   With these tools, the chemist is well equipped to
measure small and large quantities  of  pesticides
from many sources.
           TOXICITY TO AQUATIC LIFE
   Toxicity of organic pesticides  to  aquatic life will
be  understood only  through  a study  of  the  whole
environment.  As we study toxicity in the  laboratory
and  envisage  the extension of results to the field,
we  are impressed with  the  multiplicity  of factors
that  can alter toxicity.   We  realize that  one  of our
first  considerations  is the toxicity of pesticides to
food organisms.  This toxicity must be understood so
we  can predict the destruction of food supplies  or the
transport of pesticides  in food to  higher  animals
with subsequent  acute or  chronic  toxicity.  We are
also struck by  the   changes  in toxicity  caused by
influences  of  individual and  multiple  forces  in the
environment,  such as hardness,  alkalinity, and the
presence of particular ions, which often  control the
toxic properties of  organic pesticides.   Moreover,
physical features such as silt  loads, light penetration,
and  water  movements  can affect the toxicity of a
pesticide.   The  nature  of the environment,  then,
controls toxicity to aquatic life, and often to  a high
degree.
   One of the important problems in studying toxicity
to aquatic life is the interpretation of effects on groups
of  aquatic  animals.   If  good design is practiced
in experimental work, with tight control over variables,
and  adequate  replication, the  researcher  has an
excellent chance to better understand trends in toxicity.
The careful worker  who  determines the amount of
variation in response within a group of aquatic animals
usually finds it to be great. It is important to measure
and  report  variation, but even  with this knowledge
and with indications that numerous replications should
be made,  one is often led to working with individual
animals.  As toxicological work with aquatic animals
becomes  more  and  more involved, the  problem of
relating exposure to effects often becomes so complex
that groups  are unmanageable  from the standpoint
of space  and  cost.   It is then that the  chances for
predictions  of  responses  in whole  populations are
reduced,  and the investigator in most laboratories
is forced  to use individual animals. With individual
animals the biologist and the chemist can achieve
a  precision  in perceiving  relationships  between
changes in organs and systems  not usually  possible
in work with small groups of animals.
   Toxicity  to  aquatic life is  a vast subject,  and
has been the subject of an increasing amount of study
and reporting in the literature.
   We were able to consider only a few facets of the
subject in these discussions, but I am certain that
all of us will be convinced that toxicity of organic
pesticides  to  aquatic  life is  a complicated affair,
and  that  the  detection and  measurement of these
pesticides  is  an indispensable ingredient  of any
comprehensive program  for  solving  the pesticide-
wildlife problem.
                                                                                                  GPO 816-361—9

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          Effects of Time and Temperature on the Toxicity of Heptachlor and Kepone to Redear Sunfish
                                               247
              EFFECTS OF TIME AND TEMPERATURE ON THE TOXICITY OF HEPTACHLOR AND

                                      KEPONE TO REDEAR SUNFISH


                                              W.R. Bridges *
                  INTRODUCTION

   A  study  to  determine  the  effects of time and
temperature on the toxicity of heptachlor and kepone
to redear  sunfish,  Lepomis microlophus, was con-
ducted in  our laboratory at Denver,  Colorado, in
the fall of 1961. These two chemicals were  selected
because  they  were  important at the time in the
imported fire ant eradication program in southeastern
United States.

         TEST METHODS AND MATERIALS

   The  effects of  the  toxicants on  the  fish  at the
various times and temperatures tested were measured
by determination of the Median Effective Concentration
(ECso). The ECso is the concentration of the toxicant
in the water that causes  50  percent mortality of
the fish under  a given set of test conditions.  The
EC5Q values were derived by (the method of)  evaluating
dose-effect experiments proposed by Litchfield and
Wilcoxon   (1949).    After  preliminary  testing  had
established the approximate range of toxicity, 4 or 5
concentrations of the test chemical were prepared
for each  ECso value determined, and 20 fish  were
exposed at each concentration for the desired length
of time.   Mortality occurring  in each  concentration
was recorded, and the results were  plotted on log-
arithmic-probability   paper.    By   application  of
Litchfield and Wilcoxon's simplified method, the
and its confidence limits were rapidly obtained.
values for kepone were determined for 6,  12, 24, 48,
and 96 hours exposure at temperatures of 45°, 55°,
65°,  75°,  and 85°F.   Values  for heptachlor  were
determined for 6, 12, 24,  48, and 96 hours exposure
at 75°,  and for 24 hours  exposure at 45°, 55°, 65°,
75°,  and  85°F.    Further  testing of heptachlor to
obtain results comparable with the complete  range
of the kepone tests was prevented because fish of
the required size  and quality could not be obtained.

   The toxicity tests were conducted in glass  jars
that contained 15  liters of  reconstituted water.  The
water was prepared by adding appropriate  amounts
of salts  to  deionized water;  the pH and methyl
orange  alkalinity  of the  test water  measured 7.1
and 35 ppm, respectively.

   Technical grades  of kepone (90.7 percent)  and
heptachlor  (72 percent) were used  in the test. Fresh
stock  solutions were prepared each day the  tests were
started. The toxicants were dissolved in acetone, and
the aliquots  required to attain the desired  concen-
trations were pipetted into the test jars. Concentra-
tions were recorded as the weight of active ingredient in
milligrams  per liter of test  water,  and the results
reported  here are  expressed in the  same terms.
No  attempt was made to maintain a constant con-
centration of  the toxicant or  to renew the toxicant
during the  tests.   The  results,  therefore, reflect
the  concentration   present  immediately  after the
application, not necessarily the concentration  in the
water during or at the end of the test.

   The  fish used in the tests were redear sunfish
from the  National  Fish Hatchery  in  Santa  Rosa,
New Mexico.   They were all  from the same lot and
ranged  from  45 to 55  millimeters  in total  length
and  averaged  1  gram  in weight.   To  help prevent
the occurrence of parasitism and disease, the fish
were treated  with  1 ppm of acriflavin and 20 ppm
of formalin for  24 hours  within  1  or 2 days after
delivery from the  hatchery.   The  fish were held
in outdoor recirculating tanks where the water was
similar in chemical  characteristics to the water used
in toxicity  tests.   While in  the outdoor tanks, the
fish were fed a commercial fishfood.  They were
removed from the holding tanks 3 or 4 days before
being tested and were placed in the  indoor  aquaria
where water temperatures approximated those  of the
holding  tanks.  Water temperature  in the outdoor
holding tanks ranged from 60° to 70° F. The fish were
slowly brought to the  desired test temperature and
held at this temperature 24  hours before the test.
Water temperatures in both the conditioning aquaria
and test jars  were controlled with water  baths that
were equipped with refrigeration and heating units
with temperature controls that permitted  regulation
of the temperature within ± 1°  F.

   Since the test concentrations were not renewed, only
5  fish  were   tested in  each jar.   The use  of the
ratio of 1 gram of fish per 3 liters of test suspension
or solution materially reduces the chance of masking
the toxic effects of a chemical  due to inadequate
volume  of test solution  for the weight of fish being
tested.

   Artificial aeration was not required because  of the
relatively low weight of fish used in each jar. Absorp-
tion of oxygen at the exposed water surface provided
adequate amounts, even  at the highest temperatures
tested.

   The  tests  were  conducted  over  a  period  of  40
days.   To detect possible changes in resistance of
the fish to the toxicants and to assure that valid
comparisons of results could be made, frequent checks
were  made during the  course of the testing period
to determine  if  ECso  values were  different   from
  Bureau of Sport Fisheries and Wildlife, U.S. Department of the Interior, Denver, Colorado.

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248   ORGANIC PESTICIDES THEIR DETECTION, MEASUREMENT AND TOXICITY TO AQUATIC LIFE
those obtained in early preliminary tests. The results
of the check tests established that the susceptibility
of the fish to the toxicants did not change.  The results,
in addition  to  disclosing the effects  of  time  and
temperature,  reflect the  relative toxicity  of kepone
and heptachlor in  the  range where both  were tested.
In many instances the relative toxicity of a chemical
is  difficult  to  determine  because changes in  the
resistance of the same lot of fish occur  during the
holding period, or different  lots  of the same species
and size exhibit great differences in resistance under
identical conditions.  Comparing  results of different
toxicity  tests  can  lead  to an erroneous  conclusion
concerning the relative toxicity of a chemical. Hep-
tachlor was not later tested to  the  same extent as
kepone because  subsequent  lots  of redear  were
either more  resistant or  susceptible than the fish
used in the series of tests reported here.

                  TEST RESULTS

   The toxicity of kepone to redear sunfish is presented
in  Table 1.   Over the  ranges  tested, variation in
the length of the exposure period produced  considerably
more effects than did differences in temperature.  For
the periods tested, 6  through  96  hours, the toxicity
of kepone averaged  7.1 times greater at 85° than at
45°,  while  at the temperatures  tested,  45° through
85°, the toxicity for 96 hours averaged 34.0  times
the toxicity at  6  hours.   There was  a tendency for
the effects  of time to be more pronounced  at the
lower temperatures, and the effects of temperatures
to  be  greater  for the shorter  exposure periods.

   Increases   in   temperature   caused  moderate
increases in  the  toxicity  of heptachlor  (Table  2).
The toxicity  at 85°  was  4.2  times  the  toxicity at
45° for  24 hours  exposure, the only time tested at
all temperatures.   In  contrast to the  situation found
with kepone,  the  toxicity of heptachlor was only
slightly affected by the time factor (Table 3). Hep-
tachlor  was only  3.7  times more toxic at 96 hours
than at  6 hours at 75°, the only temperature  tested
at all exposure periods.   Figures 1 and 2 illustrate
the relationships of the effects of time and temperature
on the toxicity of the two chemicals.

   Since the resistance of the fish  did not change in
the period  in which the  tests were  conducted, the
results  indicate the  relative toxicity of kepone and
heptachlor at  the times and temperatures where both
were tested  (6,  12,  24,  48, and 96 hours exposure
at  75°   and  24 hours exposure at  45°, 55°, 65°,
75°, and 85°).  EC50 values for heptachlor ranged
from 0.017  milligram per liter for 96 hours exposure
at  75°  to 0.092  milligram  per liter  for24hours.
                          Table 1.  TOXICITY OF KEPONE TO REDEAR SUNFISH


Temperature,
oF
45
55
65
75
85
6 hr
Confidence a
limits
EC50
5.6
4.4
2.0
1.3
0.68
ower
4.6
3.9
1.8
1.2
0.62
Upper
6.8
5.0
2.2
1.4
0.74
12 hr
Confidence
limits
EC50
2.8
2.1
0.70
0.50
0.23
Lower
2,3
1.9
0.63
0.46
0.21
Upper
3.4
2.4
0.78
0.54
0.25
24 hr
Confidence
limits
EC50
0.62
0.54
0.34
0.24
0.12
Lower
0.57
0.49
0.31
0.22
0.11
Upper
0.68
0.59
0.37
0.26
0.13
48 hr
Confidence
limits
EC50
0.27
0.21
0.13
0.090
0.051
Lower
0.24
0.19
0.12
0.084
0.047
Upper
0.30
0.23
0.14
0.096
0.056
96 hr
Confidence
limits
EC50
0.14
0.096
0.064
0.044
0.029
Lower
0.13
0.087
0.059
0.041
0.026
Upper
0.15
0.105
0.070
0.047
0.032
 a Median Effective Concentration (EC50) with lower and upper confidence limits for the probability of the .05
   level, (p = .05), expressed in milligrams of active ingredient per liter.
 Table 2. TOXICITY OF HEPTACHLOR TO REDEAR
        SUNFISH FOR 24 HOURS EXPOSURE
Temperature, °F
45
55
65
75
85
EC50
0.092
0.064
0.047
0.034
0.022
Confidenc
Lower
0.085
0.058
0.043
0.031
0.020
:e limits a
Upper
0.099
0.071
0.051
0.037
0.024
a Median Effective Concentration (ECso) with lower
  and upper confidence limits for the probability at
  the .05 level, (p = .05,) expressed in milligrams of
  active ingredient per liter.
Table 3. TOXICITY OF HEPTACHLOR TO REDEAR
                SUNFISH AT 75°F
Hours exposed
6
12
24
48
96
EC50
0.062
0.046
0.034
0.023
0.017
Confiden
Lower
0.057
0.042
0.031
0.021
0.015
ce limits
Upper
0.068
0.050
0.037
0.025
0.019
a , _.,. /T-I/-C \ -it.
  and upper confidence limits for the probability at
  the .05 level, (p = .05,) expressed in milligrams of
  active ingredient per liter.

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           Effects of Time and Temperature on the Toxicity of Heptachlor and Kepone to Redear Sunfish    249
   100..
 2 «o
                    10      15      70

                      RELATIVE  TOXICITY
                                                 30
                                                            45
                          3       4

                     RELATIVE  TOXICITY
 Figure 1.  Comparison  of the  effects of  time on the toxicity of
         kepone (solid circle) and heptachlor (open circle) at
         75°F.  Toxicity at the various  times expressed as
         multiples  of the toxicity for 6 hours.
Figure 2. Comparisonof the effects of temperature on the toxicity
        of kepone (solid circle)  and  heptachlor (open circle)
        for 24 hours exposure. Toxicity at the various temp-
        eratures expressed as multiples of the toxicity at 45°F.
exposure at 45°;  values for kepone at comparable
times  and temperatures were  0.044 and 0.62 milli-
gram  per liter.    Considering only  the  times  and
temperatures where both chemicals were tested, the
highest toxicity for both compounds was recorded for
the 96-hour exposure at 75°. The  lowest toxicity for
heptachlor occurred at 24 hours at 45°. Kepone, how-
ever, was the least toxic at  6 hours at 75°; the ECgg
was 1.3 milligrams per liter.  The differences in the
occurrence of the least toxic  effects reflect differences
in the  influence of  the length  of the exposure period
on  the two chemicals.   Heptachlor was more toxic
than kepone,  but the degree  to which it was more
toxic ranged  from 2.6 times greater for 96 hours
exposure at 75° to 21 times greater at 6 hours at 75°.
   Only slight changes in concentrations of both kepone
and  heptachlor were required  to produce different
effects  at a  given time and temperature.  The range
in concentrations  producing zero and  100 percent
effects  was quite narrow.  In general, concentrations
that  killed  all  of the fish were  only 2 to 2.5 times
larger than concentrations that caused little apparent
effects and no mortality.

ACKNOWLEDGMENTS

   The  author wishes to express his thanks to Austin
K. Andrews,  Terrence Cockrell, and Edward L.Davis
for their assistance in  conducting the toxicity tests.

REFERENCES

Litchfield, J.T., Jr. and F. Wilcoxon. 1949. A simpli-
   fied method of evaluating dose-effect experiments.
   The  Journal  of  Pharmacology and  Experimental
   Therapeutics, 96(2): 99-113.

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250   ORGANIC PESTICIDES THEIR DETECTION, MEASUREMENT AND TOXICITY TO AQUATIC LIFE
               THE USE OF CARBON FOR MEASURING INSECTICIDES IN WATER SAMPLES

                               Charles C.  Van Valin and Burton J. Kallman *
   As  use of organic pesticides has  become wide-
spread, considerable  attention  has  been given to
developing reliable  and sensitive  methods  for  the
qualitiative  and quantitative determination of these
pesticides  in water, plant  and animal tissue,  and
soil.    In our  laboratory, paper  chromatography
and silver nitrate development of the purified sample
provide sensitivity  and  accuracy excellently suited
for rough  quantitative work. With most of the common
chlorinated hydrocarbon insecticides,  a sample con-
taining as  little as 2 or 3 micrograms can be estimated
with reasonable precision.

   Water samples present peculiar problems. Liquid-
liquid  extraction of water  can be  used to provide
suitable extracts from  a  reasonable sample size,
but in our experience, the method is slow and often
unreliable.    Serious  losses  often  occur perhaps
due to adsorption  or co-distillation.  Additionally,
in analyzing samples of extremely low concentrations,
the volumes  of sample and solvent  become quite
awkward  to  handle.   In view of these drawbacks,
and the additional  difficulty and delay when shipping
such  samples from the field to the laboratory, we
sought a better procedure that could be handled with
relative  ease by  men in  the field  and  that would
provide reproducible results in the laboratory.
   Rosen  and Middleton (1955,1958) have  described
a method  in  which  several  thousand gallons of water
are pumped  through a  bed of activated  carbon to
concentrate sufficient pesticide for infrared spectro-
scopy  or  colorimetric  procedures.    A  somewhat
similar process, but on a much  smaller  scale,  has
been described by Hancock and Laws (1955) for the
removal  of benzene hexachloride  from water.  Up
to 5 liters of sample  was  passed through a 1 -gram
column of activated carbon.  The carbon was then
extracted  with a mixture of glacial acetic acid  and
acetic anhydride, and a quantitative determination was
made by the method of Schechter andHornstein (1952).
   During the early part of our work with charcoal
adsorption, we used a similar column arrangement
where a  1-  to  5-gallon water sample was passed
through a 10-gram  column  of activated carbon.  We
later  found that  yields  were  higher  and  more  re-
producible if the carbon was stirred into  the water.
Furthermore, stirring or shaking the  carbon-water
mixture at the time of collection in the field required
less equipment and  was less cumbersome and time-
consuming than the use of columns,

PROCEDURE

   Our procedure consists  of four parts; adsorption,
extraction, cleanup, and chromatography. To a 1-
to 5-gallon  sample of water is added 5 to 10 grams
of activated  carbon.  The mixture isshakenor stirred
for about a minute;  the carbon is then removed by
filtration on a  Biichner funnel.  The filter paper and
carbon  are  transferred to a  casserole, allowed to
dry partially at room temperature, and then placed
in a paper thimble and extracted in a Soxhlet extractor
for 7 to  8  hours  with  30 percent  diethyl ether in
petroleum ether.  The solvent is then removed and
the sample is ready for cleanup.  The specifications
on  size  of  the sample, amount  of carbon, time of
stirring, and time of  extraction are  not intended to
be limiting.  Our results show that wide variations in
these factors are tolerated with essentially no change
in recoveries.

   The most commonly used cleanup method in our
laboratory is exposure to  fuming sulfuric acid.  The
extract  is taken up in n-hexane and  shaken several
times  with   2  or 3  milliliter  portions  of  a 50-50
mixture of  concentrated sulfuric acid and 18 percent
sulfuric acid.  We removed traces of acid by passing
the hexane phase through a column containing a small
amount  of anhydrous sodium  sulfate.  If additional
cleanup is indicated,  passing the extract through a
5-gram bed  of  MgO-celite (l:l,ww), with petroleum
ether-diethyl ether (94:6,  v:v)  as the eluting solvent,
has also been  used with success, although the pro-
cedure  will  degrade  DDT.  Where  necessary, the
acetonitrile-hexane partition (Jones and Riddick, 1952)
may be used in addition to one of the above methods.
An overall recovery  of only about 60 percent in the
partition  step, as  used here,  makes  its use  less
desirable, however.

   A modification of the paper chromatographic method
of  Mitchell  (1958) is used, with 2-phenoxyethanol
as the immobile  solvent and a  silver nitrate solution
as the chromogenlc reagent.   Our method has been
described in some detail by Kallman et al,  (1962).
Aliquots of  standard  solutions of the pesticide are
put on  each chromatogram, and the values  of the
unknowns are visually estimated.  These values are
then  corrected by application  of average  recovery
factors.


   A  procedure recently  tried, and still in  a pre-
liminary stage of development, involves washing the
paper with a mixture of acetonitrile in water (l:3,v:v),
placing  proper aliquots of unknowns and standards
on the paper, and washing again with the acetonitrile
solution, followed by chromatography and development
in the usual manner. This acts as a final cleanup
step and may be useful in removing some persistent
interferences, t
* Bureau of Sport Fisheries and Wildlife, U.S. Department of the Interior, Denver, Colorado-
I Robison W H_, personal communication

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                      The Use of Carbon for Measuring Insecticides in Water Samples
                                               251
RESULTS

   The procedure outlined  above was decided upon
after varying a number of factors to determine  the
combination that  gave the best reproducibility and
recovery.   Known  amounts  of  various  chlorinated
hydrocarbons  in  organic  solvents  were added  to
deionized or tap water;  the  solutions were mixed
and  exposed to  charcoal with  shaking.   Table  1
contains  a  list of factors that were varied and the

 Table 1. RANGES OF VARIATION TESTED AND
     FOUND TO  PRODUCE NO EFFECTS ON
       RECOVERY OR REPRODUCIBILITY
Variable
Amount of
insecticide
Volume of water
Amount of charcoal
Time of shaking
with charcoal
Water temperature
Time lapse be-
tween shaking
and filtration
Percentage diethyl
either in ex-
tracting solvent
Limits
10-500 ug
1-5 gal
2-10 g/gal
0.5-15 min
20-33° C
5 min-60 h
20-50%
Insecticide tested
p,p'-DDT, heptachlor
p,p'-DDT, heptachlor
p,p'-DDT
p,p'-DDT
heptachlor
p,p'-DDT
p,p'-DDT
limits  between which no effects on recovery or re-
producibility were  found.   The standard conditions
were: 1 gallon of water, 50 micrograms of insecticide,
10 grams of charcoal (Nuchar C-190, 30 mesh), 1-
minute shaking period at ambient temperature (ca. 25°
C), immediate filtration, and extraction with 30 per cent
diethyl ether in petroleum ether.  These factors were
varied singly.
   Three  factors were found to  affect recoveries.
One of these was the type of charcoal used.  In addition
to Nuchar C-190, we tried Cliffs Dow 10x30 activated
carbon, which  gave drastically reduced  recoveries
with heptachlor.  Another factor was the manner of
agitating the water-char coal mixture. When 5-gallon
samples were stirred vigorously with an electric stir-
ring motor for 15 minutes in open containers, recover-
ies were  reduced  to  less  than half.   Accordingly,
such samples are now stirred manually for 1 minute, or
the closed container is  rolled or  shaken for 1 minute.
The manner of drying the charcoal following filtration
is also of importance.     The  drying needed to
permit  efficient extraction should be done near room
temperatures;  lowered recoveries appear to result if
drying is performed at  elevated temperatures (ca. 40°
C) in  an  air  stream.   Therefore, we  merely allow
the  charcoal  and  filter papers to stand at room
temperature until only  slightly damp.   There seems
to be no advantage in allowing them to reach complete
dryness.
    Table  2 contains the results of all determinations
 made  within  the  range  of  variations  included  in
 Table 1.  These  extracts  were cleaned  up by the
 sulfonation process alone.

                    DISCUSSION

    The method described is suitable for rough quanti-
 tative determinations.   It is being  used currently in
 our laboratory for the  analysis of water samples
 from  various  field  operations  and  experimental
 stations.  In some cases the water-charcoal mixtures
 are brought to the laboratory; in others, when filtration
 at  the field site is feasible,  the charcoal and filter
 papers alone  are  sent.  The  main advantage of the
 procedure, compared with liquid-liquid extraction,
 is  the avoidance of the spurious  low and  negative
 results that were often obtained when water samples
 were  sent to the  laboratory in glass or plastic con-
 tainers.   An additional benefit is the savings in time.
 The  liquid-liquid  extraction  of numbers of water
 samples requires much more actual working time than
 a  charcoal  method;  this  is  especially  true when
 large  samples are used due to anticipated low con-
 centrations of pesticide.  Furthermore, except for the
 necessity of space on the Soxhlet apparatus, the char-
 coal method requires less laboratory space and less
 glassware.

    One difficulty with this method that has  not been
 mentioned  is  the presence  of an artifact on the
 cnromatograms. An extractable substance, apparently
 present on the unused  charcoal in  varying amounts,
 reacts with the chromogenic reagent and  appears
 with an Rf identical  to that of DDE  in our chromato-
 graphic  system.  It does not interfere seriously with
 any of the insecticides with  which we have worked
 to  date.   It is probable that a rigorous pretreatment
 will be  necessary to remove this  substance.  Such
 a pretreatment would necessitate the redetermination
 of recovery factors.

    Preliminary work with malathion, with procedures
 identical  to those described above, indicate that the
 charcoal  procedure  can be used to determine this
 organophosphorus compound in water. The amounts of
 malathion extracted from charcoal  were determined
 by fly bioassay,  without cleanup.   We are hopeful
 that the  procedure can be applied to  a wide range
 of  insecticides,  both chlorinated hydrocarbons and
 others.

     Table 2.  RECOVERY OF  CHLORINATED
HYDROCARBON INSECTICIDES FROM WATER WITH
                  NUCHAR C-190

Insecticide
p,p'-DDT
heptachlor
heptachlor
epoxide

No. of
determinations
33
21
7

Range
37-60
50-93
70-92
Percentage
recovery
Median
45
73
83
Average
46
72
80

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252    ORGANIC PESTICIDES THEIR DETECTION, MEASUREMENT AND TOXICITY TO AQUATIC LIFE
                                              REFERENCES
Hancock, W. and E.Q. Laws. 1955. The determination
of traces of benzene hexachloride in water and sewage
effluents.  Analyst, 80: 665-674.

Jones, L.R. and J.  A. Riddick. 1952.  Separation of
organic insecticides from plant and  animal tissues.
Anal. Chem., 24: 569-571.

Kallman, B.J., O. B. Cope, and R.J. Navarre. 1962.
Distribution and detoxification of toxaphene in Clayton
Lake, New Mexico.  Trans.Amer.Fish Soc., 91:14-22.

Mitchell,  L. C. 1958. Separation and identification of
chlorinated organic pesticides by paper  chromato-
graphy.   XI.   A  study of 114 pesticide chemicals:
technical  grades  produced  in 1957  and reference
standards.  Jour. Assoc.  Off. Agric. Chemists,  41:
781-806.

Rosen, A. A. and F. M. Middleton. 1955.  Identifica-
tion of petroleum refinery wastes in surface waters.
Anal. Chem., 27: 790-794.
Rosen, A.A., and F.M. Middleton, 1958.  Chlorinated
insecticides in  surface waters.   Division of Water,
Sewage, and Sanitation Chemistry, American Chemical
Society, 133rd National Meeting, San Francisco.
Schechter, M.S.  and I. Hornstein.  1952. Colorimetric
determination of benzene hexachloride. Anal. Chem.,
24: 544-548.
                                           DISCUSSION-Partl.
   After a few specific questions on the relationship
of the effects of time and temperature on the acute
toxicity of heptachlor and kepone to red ear sunfish
the discussion soon turned to bioassay procedures and
methods for the determination  of  "safe levels" of
toxicant in the aquatic environment.   The interest
in acute and chronic toxicity of pesticides to aquatic
life  that  was  so  evident in the  second  seminar
was lacking. Throughout the  seminar it appeared that
there was much greater interest in chronic toxicity
and  the measurement  and evaluation of sub-lethal
effects  than in acute toxicity, using death as the end-
point.   Some  other  end-points of laboratory  evalu-
ation of a  pollutant that  were  suggested were
histo-pathological   effects,    effects   on   protein
metabolism, growth, and  behavior.  There was little
discussion, however, of the significance of these sub-
lethal  effects on the ability  of the  test organism to
survive, grow,  and reproduce in the environment.

   It was pointed out that there was much variation
in published reports on the acute toxicity of pollutants
to fish. Furthermore, it was suggested that there was
great variation in toxicity results  of  a  pollutant to
fish even in the same laboratory.  It was suggested
that this variation in toxicity toward a species might
be a laboratory artifact rather than a "real" variation.
The laboratory toxicity of a pollutant is often greatly
dependent on a multiplicity of  physical,  chemical, and
biological factors.

   A discussion  was held  regarding  the use of a
standard fish for bioassays and for basic physiological
and  biochemical studies.   A  standard  fish would be
a good basis of comparison of toxicity between various
laboratories.   It  was  pointed out  that even  though
there was a standard fish, there  still would be great
variation  in the environment of various laboratories.
The guppy and bluegill were  suggested as reference
species. Water quality studies in any specific pollution
study should be oriented toward the important species
in that environment.

   There  was some disagreement with the methods
of computing  and expressing the results of  toxicity
tests.   It was pointed out that  the LD50 still occurs
in the  literature of fish toxicity,  even though the
toxicant is bioassayed in terms of concentration rather
than a known dose. The term LCsg is the concentration
of the toxic compound in the aqueous medium that will
kill  50 percent of the animals exposed for a specified
period  of  time.    Furthermore, when lethality  is
measured, the term LC5Q ig more specific than the
general term, EC5Q,  the concentration that, on the
average, will  affect 50 percent of the test animals.

   Several  participants  seemed to be unaware  of
"Bioassay Methods for the Evaluation of Acute Toxi-
city  of Industrial  Wastes  and Other  Substances to
Fish,"  as  published  in Standard  Methods for the
Examination of  Water   and  Waste  Water, which
states that "Unlike  the lethal concentration (LC) the
term,  'tolerance limit,' is  universally  applicable in
designating the effective level of any measurable lethal
agent, including high and low temperature, pH, and
the  like.   For this  and  other reasons, the term
'median tolerance  limit'  and  the  symbol,  'TLTO'
are recommended,"

   In the  laboratory determination of environmental
requirements  of aquatic life to serve as the basis
of water  quality criteria, the real  pay-off is in the
field.   Bioassays  can  give only  an  indication  of
toxicity and of the physical, chemical, and biological
factors affecting toxicity.  In addition to laboratory
studies ecological  studies will  be necessary for the
determination of water quality  criteria for pollution
control.

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                             How Should Agricultural Pollutants be Controlled?
                                               253
                     HOW SHOULD AGRICULTURAL POLLUTANTS BE CONTROLLED?

                                             C. H. Hoffmann *
   To  protect human health and  fish  and wildlife
resources, there  is  currently much public concern
about water  pollution that may  result from causes
such as land-management practices leading to siltation
of   streams,  improper   treatment  of  industrial
chemicals before  discharge in waters, mine wastes,
radioactive wastes, raw sewage, household detergents,
and  agricultural chemicals.  These pollutants  must
be carefully  considered in connection with the major
beneficial uses of water; namely,  for domestic con-
sumption, agriculture, aquaculture, industry, recrea-
tion,  navigation,  power,  and beauty of landscape.
To maintain  or  restore the suitability of our waters
for the above purposes  requires a determination of
water quality characteristics for each of these uses
(Cottam and  Tarzwell, 1960).  Otherwise, it will not
be possible  to measure effectively water pollution,
determine  needed  correction, or  evaluate  control
measures properly.  This  paper will be limited to a
consideration of silt, fertilizers,  and pesticides as
water pollutants.

      NEED FOR AGRICULTURAL CHEMICALS

   Agriculture is the United States' biggest business,
employing  more than seven million people on its
3-3/4 million farms and ranches.  It is significant
that  these seven million produce the food and other
commodities   consumed  by our  185  million people.
Each farm worker today grows enough food and  fiber
for 27 people. A hundred years ago each farm worker
produced enough food and  fiber for only five people.
Moreover,  Americans are  the best fed  in the world
and at a very reasonable cost. Agricultural chemicals
have  played  an important part in the technological
advances that have made this possible.  Because of
this great efficiency  on  the farm, much manpower is
available for  other pursuits.

   Everyone  is  familiar with the  great increase in
yields of  various  crops attributable  to the use of
synthetic fertilizers.  Each year  additional farmers
find  that it is profitable to make greater use of fer-
tilizers to produce an abundance of high quality crops.
The  increased use of fertilizers  along with other
improved practices makes  it possible to produce more
crops  on  smaller acreages  than  heretofore.  This
releases land, some  of  which is more desirable for
forest and recreational purposes, and helps to alleviate
certain siltation and  agricultural chemical pollution
problems.

   There  is  no question  about  the importance and
necessity  of  agricultural chemicals, including pesti-
cides, in producing and conserving  food, feed, and
fiber and in protecting plants, animals, and man  from
serious diseases in this country.  Sales of pesticidal
chemicals, including insecticides, fungicides, rodenti-
cides,  and  herbicides, at the basic manufacturers'
level,  amounted  to  $285  million in  1960  (Shepard
et al.,  1961).  The volume of pesticides required to
control pests continues to increase each year and,
along with fertilizers, is an integral part of our highly
efficient agricultural production.  Despite the wide-
spread  use of pesticides,  however,  losses due to
pests cost this nation around 11 billion dollars annually.
If pest control measures were not available, the losses
each year would  be several times this figure.   In-
secticides have provided outstanding control for many
insects that damage or  destroy fruits, vegetables,
tobacco, sugar beets, sugarcane, cereals, cotton, pas-
tures, ornamentals, and livestock. Many citizens are
not aware  of the hazards of pests in crop production;
they are  accustomed  to buying almost any desired
foodstuff of high quality at the chain store.  If pesti-
cides were banished, however, as has been suggested
by some writers, many products would no longer be
available, others would be of very  poor quality, and
the cost of foods would be higher.

   In addition to controlling insects on growing crops,
insecticides  are used  extensively to protect  grain,
foodstuffs, clothing,, wood products, and many other
materials from insect attack during transit and while
in storage.

   Insecticides have also been used widely to protect
members of our Armed Forces from insect attack.
Even with this help, however, malaria cases exceeded
battle casualties in  many theaters during World War
II,  for example, by 8 to 1 in New Guinea and 10 to 1
on Guadalcanal (Holway, 1962).  The value of insecti-
cides for the protection of civilians from insect attack
is of even greater importance.  It  is estimated that
during  the  first  10 years of  use  5 million lives
were saved and  100  million illnesses prevented
through the use of DDT for controlling such diseases
as  malaria,  typhus, and dysentery  (Knipling,  1953).
Of course, since that time millions of additional lives
have been  saved and additional hundreds of millions
of illnesses prevented.  Largely  through the use of
modern insecticides for mosquito control and the use
of drugs, progress is being made to eradicate malaria
on  a world-wide  basis.  In the United  States, from
1942 to 1953, approximately $54  million of Federal,
State, and  local funds  were spent on the use of DDT
and  other  control  measures that resulted in  the
eradication of malaria  that  heretofore had been
costing this  Nation almost  10 times  that amount
annually in sickness  and loss of production  (Fritz
and  Johnson,  1960).  Writers  who condemn the use
of insecticides  forget  that malaria was a serious
problem in the  U.  S.  not too many years ago and
that in recent years eastern encephalitis transmitted
*Entomology Research Division, Agricultural Research Service, U S. Department of Agriculture, Beltsville, Md.

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254    ORGANIC PESTICIDES THEIR DETECTION, MEASUREMENT AND TOXICITY TO AQUATIC LIFE
by mosquitoes killed about a dozen persons in an out-
break  in  New Jersey.   Insecticides  have also been
used  extensively for the  control of nuisance mos-
quitoes, biting flies, ticks, andchiggers. This permits
farmers  and livestock  men to work  in comfort  and
people to enjoy living in suburban  areas and pursue
recreational  activities around fresh and salt waters.

   Forests must be protected from insects, diseases,
rodents, and other  pests if we are to have (1) lumber
and other wood products; (2) clean water for irrigation,
hydroelectric power, industrial, and  domestic water
needs; (3)  meadows and grasslands for  grazing  do-
mestic livestock and wildlife; (4) suitable habitats for
fish  and wildlife; and  (5) scenic areas for camping,
vacationing, and recreation.  Some 30 million Amer-
icans  spent  nearly $4 billion in about 658 million
days of hunting and  fishing in 1960 (National Academy
of Sciences,  1962).  To protect these values, millions
of acres of forest land have been successfully sprayed
with DDT  for the  control of widespread  outbreaks
of defoliating insects. Many apparently well-meaning
and conscientious conservationists have expressed op-
position  to  such programs.  At  the same time I
wonder if they have weighed the generally minor and
temporarily adverse effects on fish, wildlife, and their
food organisms that such treatments might  cause
against the substantial damage that usually occurs to
wildlife habitats  when insect  outbreaks run their
course. The outbreaks are often followed by devastat-
ing fires  and, as  a consequence,  loss  of timber,
animal habitats,  fish and wildlife, and undesirable
water pollution.

   Herbicides are used extensively for the control of
weeds that compete with agricultural  crops, undesir-
able brush,  and  aquatic  weeds.   The conversion of
brushland and weed-infested lands to grass can in-
crease the availability of water for livestock and irri-
gation and the amount  of water  stored  in the soil.
Aquatic weeds substantially  reduce  the velocity of
water flow in irrigation and drainage canals increasing
siltation and  reducing carrying capacity of waterways.
Aquatic weeds also  reduce  recreational values of
waters by interfering with fishing, swimming, boating,
and navigation. Moreover, the decaying organic matter
produced by aquatic weeds causes off flavor sin potable
waters.

   These examples are representative of many ways
in which  agricultural chemicals are  used to man's
advantage.   These  benefits include unrecognized im-
provements  in  recreational  and  aesthetic values.
At the same time, however,  adverse  effects  have
resulted  from their  use, including the pollution of
water.

    STATUS OF AGRICULTURAL POLLUTANTS

Silt.—One  of the great problems today is to increase
the efficiency of  water use and promote water con-
servation  by improving soil and water  management
practices.    Silt from  eroding  agricultural lands,
denuded forests,  and stream banks may be deposited
in reservoirs, in stream channels, on flood plains,
or in municipal areas.  For example, the annual silt
load carried by the Potomac River is estimated to
be 40 million cubic feet, that of the Mississippi Basin
above the delta about 500 million tons per year.  This
loss of  soil represents important economic losses
and at the same time pollutes water. Dissolved salts,
suspended sediment, and turbidity are recognized as
impairments to water  quality.  Accumulation of salts
and  toxic materials in  soils  is one of the hazards
of irrigated  agriculture.  The leaching of accumulated
salts in  irrigated soils with water of low salt content
may increase dissolved solids in return flow and thus
aggravate water  problems  for other users.  More-
over, muddy or turbid waters can have  a detrimental
effect upon  fish and other aquatic  animals.  A con-
tributing factor has been the demolition of forested
areas, exposing  the  raw  land to  erosion, to take
care  of  our expanded population needs in the  form
of new housing developments,  industries, and super
highways. Over the years many constructive measures
have been undertaken to preserve the  soil and to pre-
vent siltation  in  waterways.  Gradually the grassy
prairies  that  were  temporarily farmed  have  been
restored to  a permanent grass cover, some of which
can be grazed.

   Soil scientists have  surveyed more than 700 million
acres of land.  They have classified and mapped each
kind of soil  according to its capabilities and manage-
ment needs  for the production of field crops, grasses,
and trees.  Today there are over 2,900 soil conser-
vation districts  that furnish  information  and help.
Moreover, over a million farmers share costs with
the government (more than $400 million in 1961) in
carrying  out  conservation practices on  about 340
million acres.  Such extensive activities will contribute
much to the  reduction of siltation as a water pollutant.

Fertilizers.—Some fertilizers are bound to reach our
rivers and  water  storages when  you  consider  the
many tons utilized in  the  cities  and on the farm. In
1959, some  25 million tons were used onfarms alone.
Fertilizers  find their  way into natural water mostly
during runoff and from soil leachings.  Under certain
conditions  solutes from unusually heavy fertilizer
applica'ions on agricultural land may  reduce water
quality.  On the  other hand, small amounts entering
farm ponds, lakes, and rivers are beneficial in  in-
creasing the numbers of  plankton and other life that
lead to better  fish production. Thus far it appears
that the  important pollutional  effect  of fertilizers is
the  addition of nutrients to the  water environment.
According to  a  recent report of  the  U. S. Public
Health Service (1962), "These added nutrients (fer-
tilizers) are capable of supporting and of ten do support
heavy  aquatic  growths, bacterial,  algal,  vegetative,
and  others,  particularly in impoundments.  Many of
these forms of aquatic growths improve the fishing
environment, but usually  this proves to be  a  more
serious detriment than benefit because such growths
often cause  serious tastes and odors in water supplies
that are difficult and expensive to remove.  Stream
pollution from  agricultural fertilizers, supplemented
by the increasing amounts of nutrients from munici-
pal and industrial wastes, is becoming a water pollution
problem that may reach national significance.  Awide-
spread increase  in the growth of nuisance organisms
and  plants  would have serious degrading effects on
water quality and use."

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                             How Should Agricultural Pollutants be Controlled?
                                               255
Pesticides.—The use of various pesticides for the con-
trol of insects, diseases, nematodes, rough fish, weeds,
aquatic vegetation, brush, unwanted birds, and rodents
varies from year to year, but the total manufactured
output exceeds  500 million pounds.  Many of  these
materials  are applied by ground equipment and air-
craft,  and some of the chemicals reach our water-
courses.   They may be applied directly to the water,
drift into water during the treatment of adjacent farms
or forest, or washed in if soil erodes from agricultural
land that  has been sprayed.  Only fragmentary data
are  available to  point up  the true effects of these
materials as water pollutants.

   It is estimated that about 50 million acres of agri-
cultural  land are  treated with herbicides annually.
When materials recommended for use on terrestrial
areas are used adjacent to aquatic areas, there is some
poisoning  hazard  to wildlife;  however,  most of  the
chemicals  can be used for recommended purposes and
at recommended dosages without serious immediate
effects on  wildlife or food-chain organisms (George,
1960b). Those chemicals used directly for the control
of aquatic  weeds and any that might leach from agri-
cultural lands would become water pollutants.

   The total amount of insecticides (active ingredients)
used in an average year in the United States is esti-
mated to be 225  million pounds. Estimates also indi-
cate that   less  than 5 percent of the acreage of  the
48 states, exclusive of Alaska and Hawaii, have insecti-
cides applied on them in an average year; and only
.41  percent  of  the total area generally considered
favorable  to  wildlife,  such as forest, grassland pas-
tures,  and wildland have insecticides applied on them
in an average year (Hall,  1962).   Moreover,  recent
estimates show that 85 percent of the acreage planted
by our farmers and ranchers  to  crops  each year is
not treated with  insecticides  (Hall,  1962).

   Following the release of  DDT for civilian use, a
number of research studies were conducted to deter-
mine its  effects  on terrestrial and aquatic  insects
and  fish and wildlife in order that recommendations
might be made to utilize the insecticide for control
of destructive insects with minimum effects on other
life. It was soon deter mined that effects were greatest
on aquatic species, particularly bottom insects that
serve as fish food. The results of studies with DDT
and  many  other synthetic organic insecticides have
been summarized  by a number of workers including
Rudd and Genelly (1956), Hoffmann  (1960), and George
(1960a). In general, on the basis of studies conducted
by many individuals over the past 17 years, the con-
tamination of ponds,  lakes, streams, and rivers with
pesticides  that  has been harmful to fish and other
aquatic life has been minor  in  relation to  the large
amounts used. In fact, several writers have concluded
that agricultural chemicals are rather minor as water
pollutants  in comparison with industrial and domestic
wastes and other well-known water pollutants.

   With particular reference to  wildlife, a  special
committee  established by the National Academy of
Sciences-National Research Council (1962a) comment-
ed as follows:   "With the thousands of tons of pesti-
cides that  are used each year in the control of pests,
it may be concluded that, to date, the impact on wild-
life, although not disastrous, is just cause for concern.
Considered from a  broad point of view, the known
impact of pesticide  use  on  wildlife has been con-
siderably less  than  that  caused by other everyday
activities of man; yet it is important and every effort
should be made to keep losses to the minimum as the
use  of chemicals  increases.   Additional research
is needed to evaluate the impact of pesticides on
fish and wildlife." It is recognized that the occasional
improper disposal ofpesticidalwastesfrommanufact-
uring plants, the cleaning of spray equipment in or
near ponds or  streams, the use of heavy pesticide
applications in eradication programs and experimental
studies,  and the spraying of agricultural crops and
forests have caused  water pollution and some losses
of fish and other wildlife in limited areas.  Fortunate-
ly, nature  has been  liberal in providing  a high re-
productive potential for wildlife  species, and there has
been a remarkably quick  reestablishrnent of species
where losses have been sustained. Actually millions
of acres in this country are treated annually to con-
trol or eradicate dangerous insect pests without any
substantial damage to other interests.

   Although the  record on the use of insecticides and
other  agricultural  chemicals is good, there is no
room for complacency. With the increased use of these
materials, which is surely to be the case, a determined
effort  must be  made through research to ascertain
the full story in regard to effects of different materials
on various plants and animals that serve  as food for
larger animals,  methods to measure the amount of
such materials  that contaminate  water  resources,
and  particularly, ways to remove these foreign ma-
terials from our water supplies.  With regard to water
pollution in rivers, DDT has been recovered in amounts
ranging from 0.001  to  0.02  ppm  from the Detroit,
Mississippi, Missouri, and  Columbia Rivers.   The
amount of DDT  recovered from  municipal water that
has  been purified is  too small  to  affect humans and
actually constitutes a minor part of their exposure to
the insecticide (Nicholson,  1959). Specialists in water
pollution believe that when insecticides are  not present
in sufficient quantities  to kill fish, they will not con-
stitute a public health hazard in drinking water.
Rotenone and toxaphene can be removed from water
during the  purification process by use of activated
carbon.

   Recently a study  was made  on the water quality
and  aquatic life in a 2.7-acre pond within a 40-acre
watershed, devoted largely  to peach production, where
parathion  and minor amounts of chlorinated hydro-
carbon insecticides had been used for insect control
previous to 1960. The total amount of parathion applied
in the watershed during the 1960 season was approxi-
mately 152 pounds active ingredient.  Before insecti-
cide use in 1960, 1.90 ppm parathion was  recovered
from pond  bottom mud but only 0.02 ppb from two
water  samples  (Nicholson etal., 1962).  Apparently
most of the parathion entered the  pond adsorbed on
soil  during a period of accelerated erosion. Parathion
(0.01 ppb) was present in  water collected 4 months
after the last application of insecticide in 1960.  This
amount and the  residue in the mud did not appear to
affect the fish, zooplankton, immature aquatic insects,

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 256   ORGANIC PESTICIDES THEIR DETECTION, MEASUREMENT AND TOXICITY TO AQUATIC LIFE
or  Oligochaeta populations.    However,  there  had
been  a  significant  reduction  in immature aquatic
insect numbers due to adults being killed by exposure
to parathion residues in the watershed.

   This general review  has pointed up  some of the
problems associated with soil and water use and efforts
under way to control soil erosion and thus prevent
water pollution by siltation and agricultural chemicals.
There are also problems  associated with the use of
agricultural  chemicals,  particularly pesticides,  and
the remainder of this  discussion will  cover ways
in which pesticides are presently controlled and also
will suggest additional ways to help meet the problem
of controlling agricultural pollutants.

LEGISLATIVE  CONTROLS

   Legislation has had a great  influence on the safe
use of agricultural chemicals.   The first law became
effective  in  1910 and concerned the manufacturing,
labeling, and sale of insecticides and fungicides. During
the ensuing  37 years many  chemicals  were added
and formulations became more complex. The Federal
Insecticide, Fungicide, and Rodenticide Act of 1947,
administered by the U. S. Department of Agriculture,
was  modified  with  broadened  authority  to include
herbicides, rodenticides, sanitizers, and disinfectants.
Registration of a label was required before apesticide
could be offered for shipment  interstate.  The label
was required to include adequate  precautionary in-
formation to protect the user and the general public.
When applying  for registration, the manufacturer of
the pesticide is required to furnish pertinent informa-
tion on the  composition of the  material, rate  and
timing of application,  the precautionary measures to
be observed, the amount of residue likely to remain
when  used as  directed,  and  toxicological data in
support  of a petition for a tolerance.   The facts
are reviewed by  specialists in the Department of
Agriculture who also may consult with state experiment
stations  and private laboratories to make full  use
of all available information.  The scope of the Act
was enlarged again in 1959 to include nematocides,
defoliants, desiccants, and plant growth regulators.
Recently the Department's Pesticide Regulation Divi-
sion has  been given authority  to regulate poisons
and devices  for the control of  a variety of wildlife
pests.

   The  Miller  Pesticide Residue  Amendment to the
Federal  Food,  Drug,  and Cosmetic Act of 1938,
the so-called Miller Amendment, became effective in
1954 and  is administered by the U. S. Department of
Agriculture and the Federal Food and Drug Adminis-
tration.  This law requires the thorough pretesting of
a pesticide  chemical before it can be sold interstate.
The manufacturer must  provide detailed data to the
Department to  show how much  residue, if any, will
remain  on a crop after  application and must furnish
data on  the  degree of  toxicity of the pesticide to
warm-blooded animals.  The Food and Drug Admini-
stration establishes  a tolerance or maximum amount
of residue of  a chemical  that may legally remain
in or  on a raw agricultural commodity when it enters
interstate commerce.  This level is deemed safe for
humans.
   Laws and regulations in more than 40 states either
duplicate the same Federal  requirements within the
state  or establish similar requirements to protect
the safety  of consumers.   State laws also require
labeling to  warn  users of any possible hazards in
using chemicals.

   These Federal and state  laws  have done much to
bring about a thorough study of chemicals, including
extensive pretesting, before they are marketed. More-
over, the  strict  regulations regarding  usage and
amounts that may remain as residues have emphasized
anew the need for applying only that amount of material
required for  pest control; this  factor in itself has
avoided much unnecessary contamination of the en-
vironment, including our waters.

   The  above restrictions by law have  come  about
as  a  result  of  years of  careful  study, and this
would  seem  to  be the appropriate way to approach
any difficult  problem.  In recent years, as a result
of much adverse publicity  on pesticides,  some of
it of  the scare type,  some  state legislatures have
held special hearings  on the pros  and  cons  of the
danger of pesticide use. Such hearings have been held
in the states  of  California, Michigan, and Wisconsin
and many specialists have been called to testify. To
date, however, in view of the testimony received, they
have not to my  knowledge found it necessary to pass
any additional laws to  control the use of pesticides.
           SUPERVISED PEST CONTROL

   The  action taken  to  control  agricultural pests
varies widely.  By and large- this action is an indi-
vidual responsibility,  determined by the producers
of crops.   Their  decisions are  influenced  greatly
by different advisors  such as  agricultural extension
service agents who furnish current information on the
control   recommendations   developed   by   state
and  Federal  research agencies.  Depending upon the
problem the  control  action may be undertaken by
the grower or he may contract to have the job done.
In any event, the grower bears a heavy responsibility
to see that the pesticide selected to control a particu-
lar  pest is  used according to the  directions on the
insecticide container, including all precautions, to
assure  safety to the spray operator; that the residue
tolerance is  not exceeded; and  that  the  chemical
does   not    drift  or  otherwise  adversely affect
his  neighbor  or other resources.   In some states
considerable   emphasis is placed on different kinds
of supervised control  where growers seek the advice
and  services  of pest control specialists.  Often they
will  contract with airplane applicators well-versed
in applying  pesticides for particular jobs.   Many
states require the licensing of pest control operators,
thus assuring that they are capable of  undertaking
certain kinds of* pest control and that they  have
the proper equipment to make applications with safety
to all.   These precautionary measures  can  greatly
alleviate drift of pesticides; however, the problem
of drift  beyond  the control of operators is one of
growing concern and more  attention needs to be given
to research on materials, equipment, and operational
procedures to reduce this hazard.

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                              How Should Agricultural Pollutants be Controlled?
                                               257
   Frequently community action is  required for the
control of pests.  For example, in the case of mos-
quitoes,  many counties or  states have set up mos-
quito abatement districts with full-time officials who
keep abreast  of local problems and utilize currently
recommended control methods, including insecticides,
when  required.   Such an  organized  effort  results
in a more  effective program  and the use  of less
material  than if  individuals  attempted  to  protect
themselves by making repeated applications of insecti-
cides.

   There are, of course, many pest problems that are
of  sufficient  magnitude  to require joint Federal-
State action.  Large-scale eradication programs are
undertaken whenever it appears that there is a good
chance to get rid of a pest rather than to use chemical
treatments  year  after year.   Such programs have
proved  feasible for  some  pests and have certainly
avoided the  use  of large quantities of pest control
materials over a large  area  each year, thus re-
ducing  the  opportunities  for  water contamination.
Such programs are conducted under  close supervision
of personnel who  are thoroughly trained in pest con-
trol activities and who are familiar with the princi-
ples of pest control as outlined in training and opera-
tional manuals. Such programs are often condemned
by the uninformed  public without weighing the alterna-
tive.   Programs  designed to  eradicate  new pests
when  first  established in  a restricted  area could
prevent the use of millions of pounds of insecticides
that would be required annually if the  pest becomes
firmly established and spreads throughout its range
of capability.  Let's consider  the cotton boll weevil.
Forty percent of all insecticides used on agricultural
crops  are  applied  to control this pest.   Drastic
measures to eliminate such a pest when first intro-
duced  and established in a restricted area would
be  justified  to avoid possible  extensive annual use
of chemicals thereafter on large areas.  Most of the
insecticides  used today  are to combat  introduced
insect pests.

      FEDERAL AND STATE PEST CONTROL
                REVIEW BOARDS

   In September 1961 a Federal Pest Control Review
Board  was  established  in  response  to  President
Kennedy's special  message to the Congress on natural
resources   in  which he  stressed  the  need for
coordinated efforts on the part of  Federal agencies
engaged in pest control programs  to insure  that all
such programs will properly serve national interests,
including public health, agriculture, and wildlife con-
servation.   The Board consists of eight  members,
two each being designated by the Secretaries of the
Federal Departments of Agriculture; Defense; Health,
Education,  and Welfare;  and  Interior.   Recently
the Board concurred with the U.  S. Department of
Agriculture in their plans for the use of insecticides
and in procedures  for the  1962  Federal-State program
to eradicate  the imported fire  ant.  The Board also
approved plans developed by the Forest Service and
cooperating agencies  to  control destructive  insects
and diseases on  the  Nation's  forest  lands.   This
approach evaluates the many factors involved in wide-
spread control and eradication programs before they
are  undertaken and  helps  resolve any  conflicts  of
interest.  The Board has an opportunity to scrutinize
any  proposals for using highly toxic pesticides  in
Federal-State pest control  activities, and if in their
opinion a material is too hazardous from the view-
point of  health, wildlife, or water pollution,  they can
veto its  use.   Weighing such factors against overall
benefits  to  be derived  from  the  use of pesticides
places a heavy responsibility on the Board members;
however, deliberate  consideration of all factors by
informed individuals  is an  important step to resolve
conflicting responsibilities.

   At  least  one state has established  a pesticide
board of scientists and administrators representing
different  disciplines  to approve  sizeable pesticide
applications   before   the  spraying is  undertaken.
Records are maintained including the time and place
of   spraying,  the    materials   used, and  weather
conditions.  Some states require the licensing of pest
control  operators  and  the  submitting  of  reports
containing   certain   information  on  the  pesti-
cide formulation used to   control a  specific  pest,
the acreage involved, how the spray was applied, and
other details.   Such a history occasionally proves
helpful  if damage  claims  are made later  and the
pesticide is  suspect.    Moreover, a  requirement
of  filing papers  on intent  to spray with certain
materials would provide officials  an  opportunity  to
approve or deny the request.

   In January 1961 a National Mosquito Control-Fish
and Wildlife Management Coordination Committee was
established  consisting of members representative  of
important government and  private agencies.  This
committee feels that individuals and groups can achieve
coordinated control in the following ways:

  "1. Promote   mutual  understanding   of  the
      problems and  methods  involved  in  mos-
      quito control and in  wildlife conservation.

   2. Standardized procedures in the fields of both
      mosquito control and  wildlife conservation.

   3. Cooperate on legislative and other matters,
      which may involve rights-of-way, ownership,
      responsibilities, and  administrative author-
      ity.

   4. Share  the  responsibility of educating and
      disseminating facts to the public.

   5. Mutually work  out plans to hold and further
      develop public  confidence in and support of
      joint mosquito  control and fish and wildlife
      management projects.

    6. Mutually stimulate, sponsor, and/or endorse
      research.

   7. Cooperatively   encourage   demonstration
      areas for control of mosquitoes by methods
      not detrimental to fish and wildlife resources.
      And, vice versa, for management of fish and
      wildlife by methods not conducive to  mos-
      quito production."

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 258
        ORGANIC PESTICIDES THEIR DETECTION, MEASUREMENT AND TOXICITY TO AQUATIC LIFE
REVIEWS OF PESTICIDE USAGE IN RELATION TO
       WILDLIFE AND WATER POLLUTION

   I am  convinced that studies and reviews of pesti-
cide problems, usage, and research needs by experts
serving  on  national committees and that forums to
discuss this  subject by private and public agencies
have a beneficial effect in crystallizing scientific and
public  opinion. Science is moving forward so rapidly
that the public becomes confused about how and under
what  circumstances  new pesticides may be  used
effectively and  safely.   More and  more there will
be  need to explain the  results of research and to
emphasize specific recommendations on the safe use
of pesticides against each pest species.  The results
of committee studies presented in lay language will
be  of  great  use to  the  public  in  bringing current
problems and methods of control into proper focus.
In fact,  the  recommendations on pesticides should
be  given careful  consideration  by  all of us for we
are  all  affected in one way  or  another  by pests as
well as by pesticide usage.

   An example of special reports of national interest
are those recently published by an overall Committee
on Pest Control and Wildlife Relationships established
by  the   National   Academy  of Sciences-National
Research Council  (1962b). In addition to  laying down
the principles that  need to be  considered before
undertaking a pest  control program, one of the sub-
committees has listed the precautions  that should
be  followed  to attain effective and  economical pest
control with  minimum harm to wildlife.  These same
precautions should  be followed to avoid or minimize
water pollution, namely:

  "1. Do not apply pesticides unless it is definitely
     established that chemical control is clearly
     the method of choice.

   2. Do not apply  unless the pesticide is regis-
     tered for the purpose intended and directions
     for its safe use are  clearly understood.

   3. Do not apply  unless the selected chemical,
     its dosage, formulation, and manner of ap-
     plication are known to  be  effective against
     the pest and least harmful to wildlife.

   4. Do not apply  in a large-scale program until
     both the chemical and the method of applica-
     tion are thoroughly field tested.

   5. Do not apply on more than the minimum area
     required for control.

   6. Do not apply in quantities greater than neces-
     sary to meet the control objective.

   7. Do not  apply without adequate supervision
     to  insure  that  all precautionary measures
     are taken."

   A number of  organizations have held symposiums
or meetings to review the status of pesticide programs,
to point  out some  of the limitations as well as bene-
fits, and to stress research needs. Special reference
might be made to those held by the National Academy
of Science, the New  York Conservation Foundation,
the  Entomological Society of  America,  the  North
American Wildlife  Conference,  the Agricultural Re-
search  Service of the U.  S.  Department of Agri-
culture, the National Wildlife Federation, the Society
of American  Foresters, the National  Agricultural
Chemicals Association, the National Mosquito Control
Association, the Soil Conservation Society of America,
and these periodic seminars on biological problems
in water  pollution held by  the U. S.  Public Health
Service in Cincinnati.  More and more these groups
are  equating differences  of opinion and conflicts of
interest.   The ultimate aim is to utilize  pesticides
for the maximum  benefit  of   man  with   minimum
damage to other  organisms and minimum soil and
water pollution.

       EDUCATION AND PUBLIC RELATIONS

   One of  the best ways to control pesticides and other
agricultural chemical pollutants  is  to educate the
public on  the  use of these materials, emphasizing
the  need  to use  only the chemicals  and  amounts
recommended for specific uses and required in good
agricultural or pest control practice. Many citizens,
particularly urbanites, are unaware  of the need for
chemicals to protect crops from pests so an abundance
of high quality food  is always available  and so our
Nation is  protected against undesirable animals and
from pests that damage, annoy, or transmit diseases
to humans, livestock, and plants. At the same time,
they need to be informed that there are certain risks
involved in the use  of chemicals and  that adequate
precautions must be taken  to  protect human life,
property,  beneficial insects, and wildlife and to avoid
contamination of our  water supplies.  All information
media available should be utilized to tell both sides
of the  story of the use of pesticides;  they are a
necessity   and can be used with a high  degree of
safety if adequate precautions are taken at all times.
Emphasis  must be placed on the slogan  "Read and
Follow  the  Label"  since this offers the  greatest
protection to the user and the  consumer.  Research
workers have  a responsibility to develop pesticide
control recommendations that are not  only efficient
but also safe  and that clearly state  any precautions
that must  be followed. Extension workers, representa-
tives of industry,  and others have a responsibility
to see that users are  provided with the best materials
to obtain  control of  specific  pests  with  the least
damage to  other  organisms.    Those with  broad
experience in the pesticide field realize that there are
certain conditions under which  there will be a loss
of fish and wildlife and beneficial insects. On the other
hand,  every   effort  should be  made to  counteract
the scare  story approach  that  alleges thatpesticides
upset the  balance of  nature everywhere (it has been
upset ever since the  Pilgrims settled in this country
and to a degree by the Indians native to  this country),
destroy all birds, kill  all  the fish in the rivers,
and basically cause cancer and other human diseases.

                    RESEARCH

   Many of our problems on the control of agricultural
chemicals as pollutants can be solved throughproperly

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                              How Should Agricultural Pollutants be Controlled?
                                               259
orientated research  programs  on a sustained  basis
with  adequate  well-trained personnel and facilities.
Speaking specifically on insect control, a strong basic
research program would contribute much to practical
control procedures irrespective of the methods used.
These needs  include studies on  taxonomy, biology,
nutrition, physiology, and  biochemistry of insects.
Pleas have been made by  those  opposed to the use
of insecticides for the development of specific methods
of insect control.   Some  have emphasized natural
control,  feeling that nature alone  will  adequately
control most of the destructive pests.  As  valuable
as natural control agents are in  helping to regulate
insect populations, the fallacy that they alone can meet
the problem must be corrected in the minds of people,
especially when the destructive insect involves acci-
dentally introduced pests. There are many unexplored
opportunities  to  use  biological  controls involving
parasites, predators, and insect diseases to control
insects, but the public must be prepared to underwrite
an adequate research  program to develop effective
and dependable biological control agents.  Eventually
the  user may also  have  to  pay more for insect
control.    The development  and  use of biological
control  agents,  especially  those  that  are  specific
against one insect, would be in decided contrast  to
the development and use of  modern wide-spectrum
insecticides that, with slight modifications in formula-
tions and methods  of  use, have been  developed  to
control a large number of  destructive insects.  In-
dustry has supported most of the basic development of
insecticides in use today.  Public supported institu-
tions have contributed  by determining in most cases
how   and  under  what  circumstances  they  can be
used  for insect control.  It is  unlikely that industry
can  be expected  to bear the cost of pioneering the
development of new  ways  to use biological agents
because  of  the uncertainty of  a reasonable profit.

   Other ways  to  control insects  are under investi-
gation, but most of the cost for such research must
also   be  borne by  public agencies.   For example,
the development of plant varieties resistant to insect
attack is  a  most  efficient  and  desirable way  to
control insects, but it takes  10 to 15 years, or longer,
to develop  each resistant  variety.  Because of the
long  time required  and  the  generally urgent need for
quicker solutions to insect  problems, there has been
only  minor support for entomological research in this
field.   Certainly  there are  many  possibilities for
new  approaches  to  insect  control such as sterility
by irradiation or chemosterilants, and some research
is under way.  The development and use of specific
attractants,  such as sex attractants, offers  exciting
possibilities to aid in detecting andcontrollinginsects.
Also,  through research there are additional oppor-
tunities  to  find  safer  conventional  insecticides or
ways  to  use  them  to  control  specific pests, as
in  attractants.   While  research on long-range and
possibly  more desirable  ways  to  control  certain
insects is underway, continued study of conventional
insecticides  is indicated because there are,  as yet,
relatively few suitable substitute methods available to
meet the depredation of hundreds of species of insects
that attack man and his agricultural crops, livestock,
forests,  granaries, and homes and that also transmit
deseases that may be debilitating or fatal.

                    SUMMARY

   There is no  question  about  the importance and
necessity of agricultural chemicals in producing and
conserving  food,  feed,  and fiber and in protecting
plants, animals, and man from serious deseases. With
the increased use of these chemicals, however, there
is great concern about their presence in the environ-
ment, particularly as water pollutants. Recent studies
of agricultural chemicals as water pollutants are re-
viewed to indicate the magnitude of the problem.  There
are  several  approaches to the control of agricultural
pollutants, including Federal and state laws and regu-
lations permitting the use  of agricultural chemicals
under  specific  conditions, supervised pest  control
programs in which trained and responsible operators
use toxic materials, and the establishment of Federal
or state pest control review boards made up of rep-
resentatives  of  different agencies or  interests to
assure that widespread control programs are conducted
in the public interest.  The importance  of educational
activities and good public relations cannot be  over-
emphasized in connection with the general safe use of
agricultural chemicals to avoid unnecessary pollution.
The interest of various national societies and other
groups representing different disciplines concerned
with various aspects of water pollution and the holding
of seminars,  symposia,  and conferences to consider
various problems are not only stimulating to research
and control workers but the release of informationas-
sociated with  such meetings  enables  the public to
become  better  informed.   Moreover,  some organi-
zations help finance studies on special problems or
seek support for research needed to answer urgent
problems.   The role of  research in the discovery of
new materials for  pest  control that are less toxic to
other organisms and, therefore, of less consequence
as  water  pollutants is  emphasized.   In addition,
more  research is  needed on nonchemical or  highly
specific chemical methods of pest control that would
obviate some water pollution problems.
                                             REFERENCES
Cottam, C. and C. M. Tarzwell.  1960.  Research for
the establishment of water quality criteria for aquatic
life.   Robert A.  Taft  Sanitary  Engineering Center
Technical Report  W60-3.   Trans, of 1959  Seminar
on Biological Problems in Water Pollution, PHS, HEW,
pp. 226-232.

Fritz,  R.  F.  and D. R. Johnson.  1960.  United States
participation in a global program for malaria eradi-
cation.  Proc. of the 47th Ann. Mtg.of the New Jersey
Extermination Assoc., pp. 51-58.

George, J. L.  1960a  Effects on wildlife of pesticide
treatments of water areas. Proceedings of the Sym-
posium on  Coordination  of  Mosquito  Control  and
Wildlife Management, 1959, pp. 94-102.

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260     ORGANIC PESTICIDES THEIR DETECTION, MEASUREMENT AND TOXICITY TO AQUATIC LIFE
George,  J. L.  1960b.   Some primary and secondary
effects  of  herbicides  on  wildlife.   Forestry Sym-
posium  "Herbicides and  Their Use in Forestry."
Pa. State Univ., pp. 40-73.


Hall,  D. G.  1962.  Use of insecticides in the United
States.  Bull. Ent. Soc. Amer. 8(2): 90-92.


Hoffmann, C. H.  1960.  Are the insecticides required
for insect  control hazardous to aquatic  life?  Robt.
A.  Taft  Eng.  Center  Tech.  Rept. W60-3.   Trans.
1959  Seminar on Biological Problems in Water Pol-
lution, PHS, HEW, pp. 51-61.


Holway,  R.  T.   1962.   Contributions of  insecticides
to national defense.  Bull. Ent. Soc. Amer. 8(2):76-80.

Knipling, E.  F.  1953.  The greater hazard—insects
or insecticides. Jour. Econ. Ent. 46(l):l-7.
National  Academy  of  Sciences-National  Research
Council. 1962a. Parti. A report by the subcommittee
on  evaluation of  pesticide-wildlife problems of the
committee on pest control and wildlife relationships.
National  Academy  of Sciences-National  Research
Council  Publication  920-A.   Wash., D.C., 28  pp.
National  Academy  of Sciences-National  Research
Council. 1962b. Part II. A report by the subcommittee
on  policy  and procedures for pest  control  of the
committee on pest control and wildlife relationships.
National  Academy  of Sciences-National  Research
Council  Publication  920-B.   Wash., D.C.,  53 pp.

Nicholson, H. P. 1959. Insecticide pollution of water
resources.   Jour.  Amer. Water Works Assoc. 51(8):
981-986.

Nicholson, H. P., H.  J.  Webb,  G. J. Lauer, R. E.
O'Brien, A.  R.  Grzenda, and D.  W. Shanklin. 1962.
Insecticide  contamination in a farm pond.   Trans.
Amer. Fisheries Soc.  91(2):213-222.

Rudd, R.L. and R.E. Genelly.    1956.    Pesticides:
Their use and toxicity in relation to wildlife.  State
of Calif. Dept. of Fish and Game Bui. No. 7,  209 pp.

Shepard,  H. H., J.  N. Mahan,  and  C. A. Graham.
1961.  The pesticide  situation  for 1960-1961. Agri-
cultural Stabilization and Conservation Service, USDA,
22 pp.

U.  S.  Public Health  Service.   1962,   Report of the
committee on environmental health problems.  Public
Health  Service  Publication No.  908.   U.S. Dept. of
Health,  Education, and Welfare, 288 pp.
                      PESTICIDE POLLUTION STUDIES IN THE SOUTHEASTERN STATES*

                                            H. Page Nicholson^
   Present-day   emphasis  on chemical  control  of
economic pests  (approximately  92 million acres in
the United States annually  receiving  pesticide  ap-
plications)-^ has  generated  special  concern  among
persons  and  agencies  responsible  for water  pol-
lution  control  and conservation.  This concern has
arisen because:

   1.  Pesticides  are poisons to some  animal or
      plant species, though their destructive quali-
      ties have great economic value when properly
      controlled.

   2.  Their effectiveness  often  demands  wide-
      spread application where ultimate disposition
      cannot always be predetermined.
   3.  Their development has  been so  rapid that
      adverse  side effects  could not be completely
      assessed, and  unfortunate incidents have at-
      tracted  special   attention  and  marshalled
      public opinion.

   In brief, this concern over pesticides in general and
insecticides specifically has its  basis in fear.  Fear
results when insufficient knowledge is  available to
permit complete understanding of a problem, real or
anticipated.

   The history  of  pesticide  pollution in water is
relatively  young.   Reports of farm pond fish kills
began  appearing soon after 1945 when DDT and other
organic insecticides became  available to the general
public.  An awareness that these compounds  might
become serious water pollutants was created rather
abruptly in  the  minds  of pollution  control officials
in 1950 when  extensive fish kills occurred almost
simultaneously in 14  streams tributary  to the  Ten-
nessee River in Alabama.  Subsequent investigation
showed that  these kills were  caused by insecticides
washed from cotton fields following passage of a storm
front with its attendant intense thunder  showers.

   The thesis that insecticides could run off the soil
with rain water was confirmed in 1954 by staff mem-
bers of the Public Health Service working in coopera-
tion  with scientists from  the U. S. Department of
Agriculture.3  Clay granules   containing 11  percent
dieldrin were applied  on  a   measured  grassy sod
  Chemical analyses required in connection with these studies were performed under contract at Clemson College, Clemson, South Carolina,
  under the direction of Dr. H.J. Webb, Head of the Department of Agricultural Chemistry.
f Chief, Pesticide Pollution Studies, Public Health Service, Region IV, Atlanta, Georgia.

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                            Pesticide Pollution Studies in the Southeastern States
                                               261
slope at the rate of 4.66 pounds of active ingredient
per acre.  Dieldrin was recovered in runoff from the
first three  significant rains after treatment in suffi-
cient concentrations to kill fish.

   These observations  in the Southeast,  reports of
DDT recovered from major rivers of the United States
such  as the  Mississippi,  Missouri and  Columbia,
and  public  concern generated by the  Imported Fire
Ant Eradication Program  of the U. S. Department of
Agriculture stimulated  the Public  Health  Service in
1959 to  initiate  a full-scale  investigation of water
pollution by pesticides. This project was established
in Public Health Service Region IV with headquarters
in Atlanta,  Georgia.

   The project's general purpose was to evaluate the
occurrence  of pesticides  in both surface and ground
waters to learn if use of pesticides was creating more
than sporadic water  pollution readily detectable by
fish  kills.   Briefly, we wanted to  learn how general
was pesticide occurrence in surface and ground waters;
what were  their less obvious effects on  organisms
living in the aquatic environment; what factors relate
to the presence or absence  of selected pesticides in
water; how well are  they removed  in  the  normal
potable water supply treatment process; and what can
be done  about it?  These questions have many rami-
fications involving  multiple disciplines.  The Pesti-
cide Pollution Studies staff in Atlanta includes per sons
trained  in  chemistry, entomology, limnology,  micro-
biology, and sanitary engineering. As the need arises
we borrow the assistance of persons trained in other
disciplines from agencies such as the Geological Sur-
vey,  Fish and Wildlife Service,  Tennessee Valley
Authority,  and various State  agencies and munici-
palities.

   The  first of  our studies  was begun in June 1959
and continues ina400-square-mile cottonfarming area
of Alabama drained by a single  river system (Flint
Creek).  This study was planned to reveal and  explain
what happens in a  natural agricultural environment.
It is a living situation, real in every sense of the word,
and,  therefore, is not subject to the frequently heard
criticism that it is contrived or artificial.  Similarly,
the scale of the study is sufficient to escape the charge
that it represents only an isolated situation.

   Agriculture is the only industry of importance in
the Flint Creek watershed, and cotton is the only crop
on which significant  quantities  of  insecticides are
applied.   An estimated 15  to 16 thousand acres of
cotton are grown annually,  mostly on small plots aver-
aging about 10 acres in size. Because the fields are
so small, virtually no insecticide is applied from the
air.  This minimizes direct application to water sur-
faces.

   On the  basis of personal interviews with  cotton
farmers  and subsequent statistical  analyses,  it  was
determined that  1959 usage of insecticide was approxi-
mately 86,000 pounds (technical).  In 1960, a year of
especially  favorable growing  conditions  for  cotton,
usage was  reduced to  59,000 pounds.   Most popular
insecticides were the  chlorinated hydrocarbons, toxa-
phene (65% of total by  weight of active ingredient),
DDT  (25%),  and the gamma isomer of  BHC  (5%).
These compounds were applied principally between
July 1 and August 15. In 1959 approximately 57 per-
cent of the total cottonacreage was treated oneor more
times whereas in 1960 only 34 percent was treated.

   A municipality of approximately 5,500 people draws
its water supply from  Flint Creek.  The stream at
this point is fed by the entire 400-square-mile drain-
age system.   Nearly continuous water sampling has
been  carried on at this water treatment plant since
June  1959 by adsorption of insecticides on activated
charcoal. Companion samples are collected for com-
parative purposes from raw and treated water. Sample
size approximates 5,000 gallons and  requires about
a week to collect.

   It has been determined that toxaphene and the gamma
isomer of BHC occur in Flint Creek and pass through
the municipal water treatment process undiminished in
quantity.  Toxaphene is present more or less year
around with heaviest concentrations occurring in late
summer during and just after the "cotton poisoning"
season.   Analyses  are not sufficiently complete to
permit statement of the seasonal trend for gamma BHC;
however,  that insecticide was present at least in the
summers of 1959 and 1960,

   The maximum quantity of toxaphene recovered was
about 0.4 part  per billion  (ppb) while the maximum
for gamma BHC  was  a  little  more than 0.75 ppb.
The true maximums are unknown be cause of recognized
limitations in the sampling and analytical processes,
and  it is assumed that quantities greater than  this
were  present.

   Sampling of the river and its tributaries showed
that contribution of insecticides occurred from the
watershed as a whole rather than from a few favorably
located cotton fields.  Further evidence indicated that
these insecticides ran off  the land surface dissolved
in water.

   DDT,which constituted 25 percent of total insecti-
cide usage, has not been recovered.  Its absence may
relate to its strong affinity for organic matter in the
soil and to its extreme relative insolubility in water
(less  than 1 ppb).

   In  1959  and 1960 limnological investigations were
conducted in Flint Creek to determine effects of in-
secticide presence on  aquatic  life.  So far as was
determined,  bottom organisms  and fish  populations
were  not reduced in number or  species composition.
Nor was  there  a demonstrable effect on zooplankton
although it  must  be added that  numbers were too
meager to  permit critical study.  Zooplankton pop-
ulations of low order are a normal condition for turbid
streams  in the Southeast similar  to Flint Creek.

   A second study involved factors related to parathion
contamination of  a farm pond located in a peach or-
chard, persistence of that insecticide, and biological
effects of that contamination.4 It was deter mined that
parathion contamination of water in  the pond  (0.02
ppb) and pond bottom mud (1.9 ppm) occurred in March
1960  during a period of accelerated soil erosion and

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  262    ORGANIC PESTICIDES THEIR DETECTION, MEASUREMENT AND TOXICITY TO AQUATIC LIFE
  before any use of parathion that year.  The source of
  parathion was the acid orchard soil where the insecti-
  cide had persisted since the previous  summer (at
  least 9 months).  On the basis of a literature survey,
  this prolonged persistence  changed  our opinion of
  parathion that had been thought to decompose  much
  more rapidly.

     During the 1960 spraying season (April 11 to August
  1), parathion concentration declined in the pond bottom
  soil, but increased in the  water to a maximum of
  1.2 ppb.  Contamination during that time apparently
  resulted largely  from windblown  spray.  No adverse
  effect on fish or  other aquatic life was evident from
  prolonged exposure to  these traces of parathion either
  in  the water  or  underlying  soil; however,  critical
  suppression of chironornid midge larvae populations
  did occur because of reduced recruitment.  The adult
  population was diminished by exposure to parathion
  spray in the terrestrial environment.

     Not all pesticide pollution problems are a result
  of usage in agriculture.  An industrial discharge of
  liquid wastes  containing parathion caused an extensive
  fish kill throughout 25 miles of a receiving stream in
  1961.   This  stream joined a river  that  flowed at
  that time  at  approximately  7,000  cfs.   Fish were
  affected  in portions of two major reservoirs of the
  river.  Affected, but living, fish takenfromthe second
  reservoir  about  100 river miles from the industry
  contained from 0.75 to 1.5 ppm of parathion.5

     A start had been made toward evaluation of pesti-
  cides and their usage in relation to water pollution,
  but much remains to be done. It is evident that pesti-
  cide pollution can and does occur. Factors determining
  the degree of pollution are: (1) water solubility of the
  pesticide,  (2) persistence  in the soil,  (3) quantity
  applied,  (4)  formulation,  (5) method of  application,
  (6) slope of  the  land,  (7)  soil characteristics, (8)
  volume and intensity of rainfall, and (9)  soil conser-
  vation practices including degree and type of vegetative
  cover.

     Occurrence in surface water of pesticides in quan-
  tities below the level acutely toxic to aquatic life may
  be rather common in areas of routine pesticide usage.
  The threshold below which no harm is caused has not
  been determined.   The recognizable threshold, not
  necessarily identical with the true  threshold, will
  depend  entirely  on the sensitivity  of  methods  for
  detecting the effect.

     Evaluation  of  effects  of  acute  exposure  is  not
  particularly difficult and is fairly well known for some
  of the fishes, a few species of zooplanktonand benthic
  organisms, as well as man.  The evaluation of effects
  of  chronic exposures  at  low levels is much more
  difficult.   Much more work in this area is critically
  needed.

     Pending more complete investigation of the possi-
  bility of chronic low level toxicity, certain actions may
  be  desirable to minimize or avoid water pollution by
  pesticides. One action that may be desirable is im-
  proved  control of aerial application  of pesticides.
  This may take the form of revised  State legislation
  where needed or other regulatory action to prevent
  incorrect or careless application of chemical toxicants
  and to  assure  adequate  maintenance of equipment.
  Twenty-two percent of the total acreage sprayed or
  dusted  in  the  United States in 1958 was treated by
  aircraft. 1  Aerial  pesticide application is a frequent
  cause  of acute fish poisoning.  In  many such cases
  improved skill in application or perhaps repair of leaky
  equipment may be all that is necessary to mitigate
  such losses.

     A second desirable action is improved education of
  farmers, pest  control operators, and the public about
  the  consequences of misuse of pesticides.  Such in-
  stances  as cleaning a spray rig in the creek, "letting
  a little poison go into a lake to see what would happen,"
  or similar thoughtless or careless acts too frequently
  have been  causes of serious episodes.

     A third action is continued efforts to promote and
  improve soil conservationpractices, especially as they
  relate to  retardation of  surface water runoff.  The
  Publi c Health Service studies have shown that transport
  of  pesticides in surface runoff can be a significant
  means of surface water contamination.
                                                REFERENCES
1. Strickler, P.  E., and  W. C. Hinson.  1962. Extent of
  Spraying and Dusting on Farms, 1958—with Compari-
  sons.  Statistical  Bull.  No. 314, Economic Research
  Service, U. S. Department of Agriculture.

2. Young,  L. A. and  H. P. Nicholson.   1951.  Stream
  Pollution Resulting  from the Use of Organic Insecti-
  cides.   Progressive   Fish  Culturist,  13(4):   193.


3. Tarzwell, C. M. and C. Henderson.  1956.  Toxicity of
  Dieldrin  to  Fish.   Trans. Amer.  Fish Soc., 86:
  245-257.
4. Nicholson, H. P.; Webb, H. J.; Lauer, G. J.; O'Brien,
  R.  E.;  Grzenda,  A. R.  and D.  W. Shanklin.  1962.
  Insecticide Contamination in a  Farm Pond.  Part I -
  Origin  and Duration.  Part  II  -  Biological  Effects.
  Trans. Amer. Fish Soc., 91(2):  213-222.
5. Personal communication,  Dr. A.  B. Arthur, Depart-
  ment of  Zoology-Entomology,  Auburn  University,
  Auburn, Alabama, re parathion content of fish.

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                             Pesticide Pollution Studies in the Southeastern States
                                                263
                                          DISCUSSION—Part 2.
   After a few specific questions on the report, "Pesti-
cide Pollution Studies in the Southeastern States," the
discussion centered  on  the philosophy of the use of
pesticides.  It was pointed out that the toxicological
problems involved in the  manufacture  and uses of
pesticides are great. The responsibility of the manu-
facturer ends with the sale of the product. Industry
is responsible  for the technical information.   With
many pesticides this does not include information
on  the  toxicity to  fish and  wildlife.    Where the
pesticide is to be applied to water for aquatic weed
control,  toxicity information is developed for aquatic
life.

   It was pointed out that a little is known about the
acute toxicity  of some  pesticides to a few aquatic
species.  There is a critical need, however, for water
quality  criteria based on long-term, continuous-flow
studies  to  determine cumulative effects of pesticides
that are neither  lethal nor significantly  harmful for
survival,  growth,  and reproduction of  aquatic life.
Also more research is needed to determine the effects
of pesticides transmitted in the food web.

   Along  with the  critical  need  for  water  quality
criteria for aquatic life, there is a great need for
methods to detect and measure pesticides  in water
and in tissues of plant and animals.

   It was indicated that more research was needed for
the control of pests without chemicals.  There are
great possibilities in  the field  of  biological control.
There is a need for more basic research and ecological
studies  in this field.

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            THE RELATION OF LAND USE TO THE AQUATIC ENVIRONMENT

                             W. E. Bullard, Jr.* and A. D. Harrison,-\  Chairmen

                     ROLE OF WATERSHED MANAGEMENT IN THE MAINTENANCE OF
                              SUITABLE ENVIRONMENTS FOR AQUATIC LIFE
                                           W. E. Bullard, Jr.*
                 INTRODUCTION
   Areas of land receiving surplus precipitation con-
tribute  surface  runoff  and subsurface seepage that
form  streams  and lakes.    Conditions  on the land
affect the amount, the timing,  and the quality of the
water reaching  streams.   It is the  purpose of this
paper to describe those characteristics of land, its
cover, its use, its development, that modify the move-
ment and quality of water, and what can be done about
them  through management.    Specific emphasis  is
placed on factors affecting the aquatic habitat.

                   DEFINITIONS

   "Watershed" may be defined as the land area con-
tributing water by surface or immediate subsurface
flow to a  lake  or to  a specific point on a stream.
Webster's New Collegiate Dictionary  says "the whole
region or area contributing to the  supply of a river
or  lake; a  drainage basin"; but we will not want to
include  areas  producing  groundwater  that moves
across  surface  divides to supply a stream, as oc-
casionally happens.

   "Watershed  management" is  defined in the U.S.
Forest Service Manual, Title 2500,  as "the protec-
tion, conservation,  and use of  the natural  resources
of a drainage basin to keep  the  soil mantle in place
and make  water available  in  a manner which best
serves  human  requirements."    It is further stated
that watershed management is not a single operation
but a complex of several activities.  We might modify
the definition to  say "which best serves the aquatic
environment," but I believe we will come to much the
same result either way.

   "Suitable environment for  aquatic life" is perhaps
more difficult to define. If we  think of it in terms of
the natural  environment and natural  range of condi-
tions in which desirable aquatic species such as trout
and salmon in the Northwest have developed, we can
determine  certain parameters  of temperature, dis-
solved material,  suspended material, and streamflow
regimen. Suitable temperatures would cover the range
within which the entire life cycle of desirable species
and their  food chains could be  completed,  and within
which the organisms could maintain reasonable growth
and reproduction rates.   The  same criteria  would
apply to dissolved material, both gas and solid,  to
suspended material, and to streamflow regimen. Thus,
the "suitable aquatic environment" would not become
too warm,  nor   too cold,  nor  change too  rapidly;
would not contain harmful loads of suspended material
that would cut down light, or dissolved material that
would be  toxic,  though  it  would contain sufficient
nutrients  to  support growth and balance removals;
and would not be subject to damaging flood flows nor
to drying up in the low-water season.

     CAUSES OF CHANGES IN ENVIRONMENT

Natural Factors

   Numerous natural occurrences  on the land have
effects on the aquatic habitat. Earth movements, from
slow gravity soil creep to sudden landslides  and ava-
lanches, add  sediment and organic debris to water-
courses, increase turbidity of streamflow, sometimes
block stream channels,  and occasionally cause dam-
aging surges.   Lightning sets fires that  destroy the
vegetation cover on watersheds  and remove riparian
shade from  streambanks; after  a fire, ash blows or
is washed into streams to bring  about drastic (though
short-lived) chemical changes,  denuded soil erodes
readily  and adds to sediment  loads  and turbidity,
runoff is rapid  and streamflow  becomes  flashy, and
less water infiltrates to underground storage to main-
tain  low-season flow.  Major floods  caused by ex-
cessively  long-continued rainfall or rapid snowmelt
tear up channel bottoms, destroy bottom biota, break
down channel banks, add organic debris and sediments
to stream loads, and pile  up debris jams that block
channels.  Ice  may be a significant factor; it inter-
feres with gas  and heat exchange, bottom ice dis-
locates  bottom  biota, surface  ice forms jams and
flood  surges,  and, influenced  by wind,  ice erodes
streambanks and lakeshores.

   There are natural factors other than physical. Ani-
mals may create situations on  the land that directly
affect water.  Beavers build dams that  make swamps,
trap sediments,  and add to the organic  load of the
water.   Big game (elk,  bear) wallow  in the streams
and increase turbidity; rangelands overgrazed by big
game are  readily eroded and cause flash runoff and
increased sediment  loads and turbidity.   Ground
squirrel burrows may cause gully erosion with sim-
ilar  consequences.   Insect infestations on riparian
vegetation  seasonally add to  the organic load  of
streams.   Leaf fall from riparian deciduous trees
and shrubs  also adds to the dissolved organic load
and to debris in  the streams.

Development and Use Factors

   Soil disturbance by road, pipeline,  and powerline
construction, by  the  timber  harvest, by farming
 ^Forester, Watershed Management, Water Supply and Pollution Control Program, Public Health Service,
  570 Pittock Block, Portland, Oregon.
 "fSenior Research Fellow, U, College of Rhodesia & Nyasaland, Salisbury, Southern Rhodesia-

                                                   265

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266
                      THE RELATION OF LAND USE TO THE AQUATIC ENVIRONMENT
operations,  or by  heavy grazing  use by  domestic
livestock  increases erosion and sedimentation, in-
creases  runoff, decreases  infiltration, and  affects
streamflow regimens.  Denudation of the natural plant
cover by fire,  by  heavy grazing, by the timber har-
vest,  by  clearing for construction, or for agriculture
has similar effects; and the loss of shade increases
stream temperatures and decreases riparian cover.
Blocking streams by dams, diversions,  culverts, etc.,
interferes with fish movement, changes stream tem-
peratures, modifies or permits regulation of stream-
flow  regimens, and creates storage  space to trap
sediment  and debris  as  well  as  to  hold  water for
increasing low-season flow.  Stream channel changes
by relocation for road construction, by encroachment
of road  fills,  or  by  levees, lining,  or  diversions,
destroy existing  habitat and modify the  streamflow
regimens.

   Addition  of  materials other  than sediments  and
natural organic debris to streams is a common con-
sequence of land development and use.  Animal wastes
from  corrals and feedlots and pastures  may drain into
streams  to increase  nutrient  loads;  it is normal
practice  in  many areas to  have  corrals and feedlots
along small  streams,  and  the stock may wallow in
the streams and break down the banks to increase
turbidity  and  sediment  loads  as  well  as organic
nutrient  loads.   Fertilizers  used   in  farming
are leached away  to  increase  the nutrient load of
streams.   Insecticides, fungicides,  and weedicides
applied  to soils  and  crops on  farms, to forest and
range areas,  or to roadside strips,  and chemicals
used  in fighting forest and range fires may  wash into
streams  with  serious and sometimes prolonged toxic
effects.   Machines used on the land and power boats
on  the water present  a  hazard of oil and gasoline
contamination;  the boats with  underwater exhausts
add  further  to the toxic load in the water with
materials in the exhaust fumes.  Cement and cement-
curing chemicals or creosoted  timbers used in dam
and other  construction on streams may  add toxic
materials to  the  dissolved load in streams.  Mine
drainage  adds highly  mineralized and  often toxic
discharges to  streams.   Dust-laying and surface-
binding chemicals used on  roads wash into streams
to provide  still further  increases in the  dissolved
and often toxic load.  Finally, the litter and garbage
and  sewage  from  farmsteads,   work  camps,  and
recreation areas often get  into streams  to increase
debris and nutrient loads.

   An index to the significance of these "additives" is
given by  the  reports  on  fish  kills for 1961.  The
deaths of some 5.6 million fish were attributed to
agricultural pesticides, and 1.1  million dead fish to
mining wastes,  countrywide,  for the  areas report-
ing.*  This is not the total for the country.

               POSSIBLE CONTROLS

On Natural Factors

   Though  we  are  not yet to  the point in weather
modification  where we can prevent the heavy rains
or rapid snowmelt that cause great floods, or where
we can  conjure  up rains  in the dry season to main-
tain  streamflow,  there  are  many  of the  natural
factors  affecting streams and the aquatic habitat that
we  can modify  and regulate.  Wildfire can be sup-
pressed and kept  from running free to despoil vast
watershed areas.   Dams  can  be built for flood con-
trol, to trap  sediment and debris, to store water
for   release  to  build  up natural  low  flows,  or to
controltemperature regimens by releases from various
reservoir  depths.   Dams need not be necessarily
harmful to the aquatic  environment. Channel clear-
ing and cleanup can remove debris jams that block
or threaten  to block streams, and reduce the bank-
cutting and sedimentation hazard. Animal populations
can be regulated;  beavers can be trapped where they
are  not wanted  and planted where they are wanted;
special  seasons and hunts can be  established to re-
duce the numbers of bear, deer, and elk;  rodents can
be poisoned; and insect epidemic  outbreaks can be
treated  with sprays.  Though such control operations
may themselves provide some hazard to water quality
and  the aquatic  environment, the  jobs can be done
carefully and with a minimum of risk.

   Regarding other natural  factors, it is easier to
avoid touching them off than to correct the results
or  control them.   Road  locations should be routed
around  areas  of unstable soil and rock to avoid
triggering  slumps and slides.  Channel relocations
and  diversions should be made with an eye  to local
topography and  soil conditions  so that  they do not
undercut steep  slopes  or  result in excessive bank-
cutting.  Riparian hardwood trees  and  shrubs can be
removed and replaced with conifers in many regions,
or at least with species that present less of a leaf-
drop problem and that are not tasty and attractive to
tent-caterpillar  colonies.

   Sometimes corrective works are needed.   Ava-
lanches tend to  repeat  in the same paths year after
year, but judicious placement of barriers and planting
of trees at  breakoff points can prevent them  from
starting.  Undercut slopes  can often be supported by
toe walls; streambanks can be stabilized with revet-
ments  and vegetation  or  protected with  wing walls.
Heavy  debris loads in streams can  be stabilized
with channel sills.  Burned areas  can be sown with
grass or mustard to provide a quick-growing cover
crop to hold the soil against erosion,  and planted to
shrubs  and trees to get  a permanent  cover re-es-
tablished rapidly.

On Development Factors

   In farming operations, there are many possible
controls.  The adoption of soil-conserving cultivation
practices,  such as cultivation  on  contour,  leaving
contour strips uncultivated between cultivated areas,
preparing  grassed  waterways,  and  avoiding  long
periods with the soil bare and open to wind and water
erosion, reduces soil movement and stream sedimen-
tation.   The use of cover crops as a  green manure
for the soil, as well as to hold the soil against erosion,
is another aid  in prevention of turbidity and sedi-
     : 9A, June 1962 issue of Water and Sewage Works Journal

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          Role of Watershed Management in the Maintenance of Suitable Environments for Aquatic Life      267
mentation in streams.  Land drainage has destroyed
many  aquatic  habitats, and  drainage  ditches have
themselves been sources of  sediment as well as
carriers of eroded material from the land above to the
streams below; but  the ditches can be replaced by
subsurface  drains or by grassed waterways, and their
gradients can be controlled to reduce erosion. Irriga-
tion waste water may carry nutrients, toxic materials,
and erosion sediments into streams; except on those
alkaline soils where heavy irrigation is used to leach
out excess salts,  irrigation can be more efficient,
by  sprinkler, for example, rather than by flooding,
to  reduce  the  waste flow  and the load  carried.

   Road construction,  perhaps the chief source  of
sediments in the Northwest, can be improved in every
phase.  Mapping out road locations to choose sites on
benches away from stream channels, minimizing cuts
and fills, and avoiding areas of unstable soil and rock
will do  much to reduce sediment contributions.  It
should also help reduce both construction and main-
tenance costs.   In the construction itself, restricting
the heavy  soil-moving operations to dry weather and
hauling excess material to safe disposal rather than
direct overcasting  to stream channels, including cut
and fill slope stabilization as a final step in construc-
tion,  and avoiding encroachment on channels, all will
cut down sediment contributions  and  damage to the
aquatic habitat.   Drainage  from the road itself as
well as intercepted drainage should be  turned off at
short intervals to avoid building  up erosive concen-
trations, and should  be disposed where it can soak
into the soil rather  than led directly  to   stream
channels. Road surfaces should be rocked and graded
regularly to avoid rut formation and muddy drainage.
Culverts  should  be installed on the natural stream
gradient; on streams  where fish passage is concerned,
culvert types and  methods of installation  meeting
state  fish and game department requirements should
be  used.    Culverts  should extend well beyond the
fill slopes   and  should be  protected with both inlet
and outlet  headwalls to prevent erosion from under-
cutting  the slopes.   Cut and fill  slope  stabilization
may require drains and toe walls and bulkheads, but
generally may be accomplished by establishment of a
dense vegetation cover of plant species adapted to the
particular region.  Maintenance of ditches and cross-
drains, road surfaces, and cut and fill slopes should
be  done  in  such a  manner that surplus soil and rock
are not overcast directly into channels, or where they
can erode into channels.

   Timber harvest layout can prescribe cuttingbound-
aries  that  leave protective strips  to shade  streams
and to  screen out debris  that  might otherwise roll
or  be washed into  streams.   Cutting units  and the
access  road system  need  to be  thoroughly planned
in  advance to  take  advantage  of topography and  to
avoid critical soil  situations.  Felling timber should
be  done  uphill away  from  channels, and  yarding the
timber  should avoid  crossing  channels.   Highlead
uphill yarding or a  skyline downhill yarding system
will avoid  soil disturbance.   Tractor yarding should
be  restricted to gentle slopes and dry soils to avoid
gouging and compaction, and skidtrails should be used
only two or  three times to avoid digging new drainage
channels on the slopes. After the logging job is done,
crossdrains should be installed in skidtrails and the
soil  should be  seeded or planted  to  provide a cover
against erosion.    Landings should be located away
from streams  and diked  to  prevent the escape  of
muddy drainage.   A clean and thorough harvesting
job will reduce the need for  fire for slash cleanup,
and avoid ash  and further erosion hazards. As with
road construction, soil stabilization afterward should
be considered  and done as part  of  the logging job;
skidtrails, landings,  and temporary spur roads
should be drained,  seeded,  mulched,  and  planted
as  the local  situation  indicates.   Throughout the
entire  logging  and  cleanup  operation, care  must
be taken to avoid stream contamination from oil and
gasoline,  whether by accidental spills or from equip-
ment operating in streams; trucks and tractors should
be kept out of streams and off stream banks as much
as possible to avoid breaking down the banks and tear-
ing up  the channel as well as to avoid direct contami-
nation. Channel crossingsshouldbe made on temporary
culverts  that can be installed and  later removed with
a minimum of channel and bank disturbance.

   Grazing by  domestic  stock on  the open range can
be restricted in  numbers of  stock and season of use
to avoid  too great decrease in density of the plant
cover  and  to  prevent  excessive soil  compaction.
This  will help maintain infiltration rates,  reduce
runoff, and decrease erosion hazards and sediment
contributions to streams.  Stock should be fenced out
of streams, and wateringplaces should be so developed
that  they are not fouled and  muddied by trampling.
This  will avoid breaking  down  stream banks and
consequent sedimentation and  turbidity. Dead animals
should be disposed by  burial or burning away from
streams.

   In pipeline and powerline  construction,  much the
same rules should be  followed as in road construction.
Adequate  drainage with safe disposal  of drainage
waters is needed for all areas of disturbed  soil  to
avoid erosion and production of sediments. Disturbed
soil  should be stabilized by  seeding, mulching, and
planting after the construction job is finished.  Pro-
vision  must be  made for  safe guards against accidental
spills or leaks  of oil or other contaminating materials
that might escape to streams.

   Mine  drainage should be  led  to  disposal by in-
filtration  into the soil  rather than  allowed to move
directly to stream channels.  Mine  dumps and spoil
piles  should be  located where they will not erode
into  channels, and should be stabilized with a vegeta-
tion  cover to keep them  from eroding. Waste waters
should be ponded to trap sediment before the waters
are returned to streams.   Gravel and road material
should be taken from quarries away from  streams
wherever possible, and wash waters should be ponded
before release. Where removal of gravel from streams
is necessary, it  should  be  done at seasons that will
not interfere with spawning and hatching of fish, and
at water  stages  and  by  methods  that will  minimize
sediment  production and damage to spawning gravels
and channel bottom biota.

   Dam construction offers  both hazards and benefits
to the  aquatic environment.   During  construction

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268
THE RELATION OF LAND USE TO THE AQUATIC ENVIRONMENT
there is of necessity excessive local soil disturbance
and considerable sediment production, but this can be
reduced with foresight and care in the various phases
of the job.  Drainage from gravel-washing operations
and  from borrow pits can be diverted to  safe dis-
posal or ponded to trap sediments before release.
Drainage from concrete mixing and curing may con-
tain toxic substances and should be diverted away from
the stream.  Construction debris should be cleaned
out of  the  stream below the project and from the
flowage area  above.    Some  Federal  agencies now
require clearing of trees and brush from reservoir
flowage areas; this operation is generally desirable
to protect  water quality, to reduce floatable debris
and flood hazards,  and to safeguard recreation use,
as well as to maintain the  aquatic habitat.  Once the
dam is built  and  its reservoir filled, its operation
can  be managed to  reduce flood peaks, to provide
additional water to stabilize  low flows, to provide
water  for filtration as may be needed downstream,
and to modify water temperatures and oxygen content
downstream.

   Recreation areas are  increasing in numbers and
size and  intensity of  use  everywhere, and present
some special  problems.  Most recreation areas and
use  are associated with water; heavily used areas
have  compacted soil  and often are  readily eroded.
Adequate  drainage  and  drainage  disposal  may  be
necessary to avoid undue erosion and sediment pro-
duction from streamside or lakeside recreation areas.
Unless  facilities for  collection and pickup  of litter
and  garbage are  made available, these things may
add  to  the  waterborne  debris load. Sewage disposal
systems adequate to cope  with weekend loads  from
use  by  thousands is also a real need at many favored
recreation  spots.   Restrictions  on motorboats  on
heavily used  lakes may be  necessary to  keep  oil
and gas and fume pollution of lake water to a minimum
to safeguard the aquatic environment.

  REHABILITATION OF DAMAGED WATERSHEDS

   Forest  and range  areas,  denuded  by fire,  soil-
disturbing  logging methods, or overgrazing, may be-
come  badly eroded  and incapable  of revegetating
naturally.   These  flood and  sediment source areas
need help;  it  can  be provided by means of contour
trenching to catch and infiltrate  storm  runoff; by
gully  stabilization  with checkdams,  bank-smooth-
ing, and revegetation; by cultivation, re seeding, fertil-
ization, and mulching on  range  lands;  and by re-
planting forest trees.   Major projects of such kinds
are underway on public lands, but more rapid progress
is needed to cover the great areas awaiting treatment.
   Avalanche areas in  the  western mountains can be
stabilized  by  rock and  brush barriers  and tree-
planting.  Work should concentrate first on the snow
accumulation and  breakoff points at the tops of the
avalanche paths.  Though avalanches are restricted
to  a  relatively small area,  they present serious
problems locally and  often carry huge loads of  rock,
soil,  and organic  debris to plug stream  channels
and cause floods.
                                     On any cultivated land, erosion by wind or water
                                  may  occur  wherever  the soil  is left bare.  Soil-
                                  conserving farming methods can prevent or greatly
                                  reduce  erosion  hazards.  Where  sheet  and gully
                                  erosion are already well advanced, preventive methods
                                  may  be useless;  terracing, gully stabilization, con-
                                  version to  forest,  and  other  practices  should  be
                                  employed.  These are well described in a number of
                                  State  and Federal  agricultural bulletins.   We need
                                  only  note  here  that  it is  quite possible  to get im-
                                  mediate and large reductions in runoff and sediment
                                  movement from eroded areas by these methods.  A
                                  planned program of watershed protection and develop-
                                  ment  is needed on about a billion acres in more than
                                  8,000 watersheds.*

                                     Debris cleanup in streams and reservoirs maybe
                                  necessary to restore the aquatic habitat to use and
                                  productivity.   Old logging operations often put huge
                                  quantities of  stumps,  limbs,  and cull logs into
                                  stream channels; usually  these  formed  jams that
                                  blocked and diverted the  stream, prevented fish pas-
                                  sage, and increased  sediment loads by bankcutting.
                                  Heavy loads of sediment  deposited  in the compara-
                                  tively  still waters   behind a  dam have  filled  or
                                  threatened to  fill many  reservoirs; as the waters
                                  become shallower they tend to  become  warmer, the
                                  advancing  deposition  deltas  tend  to obstruct fish
                                  passage, and reservoir bottoms become  coated with
                                  the fine silt and  clay particles that are  the slowest
                                  to settle out.   Sediment  removal from the reservoir
                                  flowage area is sometimes possible; in other  cases,
                                  sediment barriers can be installed upstream; but in
                                  any  case,  reduction  of  sediment  yield by  proper
                                  management and  corrective action on the watershed
                                  lands will improve the situation.

                                     Restoration of dredged areas along streams and in
                                  meadows, of quarries and borrow pits, and of strip-
                                  mine spoil piles  is often  necessary to open a stream
                                  course  to unobstructed fish passage,  to remove loose
                                  silt  and sand  and gravel  from the reach of flood-
                                  waters; and to prevent contamination of streamflowby
                                  mineralized and  silt-laden  drainage. Often this may
                                  be  best accomplished  by  stockpiling  surface soil,
                                  filling and smoothing the  mined area when the opera-
                                  tion  is  finished,  respreading the topsoil, and seeding
                                  and  planting to re-establish plant cover,  to provide
                                  shade, and to hold the loose material against erosion.
                                  A channel  of  sufficient  capacity to carry  normal
                                  high flows,  with  riffles,  pools, and  some cover for
                                  fish life, should be left open through the treated area.
                                  Some revetment or other  bank stabilization measures
                                  may  be needed  until the re-established plant cover
                                  takes hold.

                                             SUMMARY AND CONCLUSION

                                     We have covered very  rapidly and sketchily the
                                  natural, the developmental, and the use factors of the
                                  land that  may adversely  affect the  aquatic environ-
                                  ment.   We have  briefly noted their effects, and have
                                  touched upon various  ways in which enlightened land
                                  management can protect and benefit the aquatic habitat.
 *C. J. Francis and R. G. Andrews, SCS, at National Water Resources Engineering Conference, quoted on page 213,
  June 1962 Water and Sewage Works Journal-

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         Role of Watershed Management in the Maintenance of Suitable Environments for Aquatic Life
                                              269
We have by no means covered all the possibilities.
The intent has been to direct attention to and stimulate
consideration  of these problems  on the land that are
so intimately related to the problems in the streams.


   Many things of significance have been omitted be-
cause they did not appear encompassed by the term
"watershed management." One of these is the runoff
from  roofed and paved urban areas, runoff that car-
ries a goodly load of dissolved and suspended materials
unwanted  in the aquatic habitat.   Another is that of
municipal and industrial wastes.


   The  emphasis  has been on sediment production.
In the forested mountains  of the West, this appears to
be  the  most  important single  factor.   It  is also
important in the farming areas  of the Middle West
and the East.  But in the areas with less forest and
gentler  topography and more farmland, it may  well
be  that nutrients and  toxins added  to the streams
from  agricultural operations  are much more signi-
ficant.

   Much of  what has been mentioned  in the way of
preventive treatment  or management  might  be  ac-
complished by  more  effective control under existing
State laws. Still there appears room for development
of a new philosophy; i.e., that enterprises on the land
should bear the same responsibility towardprotecting
water  resources as that required of industries  and
municipalities that use the water.
                                              DISCUSSION
   Increased sedimentation of  streams seems to be
the most obvious effect of land use practices on the
aquatic habitat.   The addition of finer particles to
the bottom gravels  reduces the niches where many
benthic organisms live.   Perhaps the direct effects
on  eggs are  among the most important.  There is
a  smothering effect from silt coatings and a de-
creased permeability of the bottom gravels reducing
the flow of water over  the eggs.   The turbidity re-
sulting from the increase in suspended  particles
also reduces the light penetration and photosynthetic
rate.
   Not all sedimentation is a result of obvious opera-
tions such as mining and  cultivation.   Instances are
on record in which the activity of ducks has reduced
fish  egg survival.   Perhaps the trampling of stream
banks  by cattle may be far more  important than is
commonly recognized.  Changes in the stream bank
brought about by cattle or man-made channel changes
may produce a cycle of changes, which may be car-
ried clear to the mouth of the stream.  Usually, these
changes are not desirable.

   The feeling among the discussants seemed to be
that,  ideally for  fish  production,  partial tree cover
of  the  banks, something less  than complete  bank
stabilization, and an increase in rainfall infiltration of
the soil are  all  desirable goals along with reduction
in siltation and turbidity.  However, the attainment of
such  goals may affect the stream flow  patterns and
reduce the total amount of water reaching the stream.
In more arid areas, grasses are more desirable than
trees because they  achieve stabilization of soil  but
do  not  lose  as  much water  through transpiration.

   In any  case,  the optimum  conditions for fish
production will have  to  be sacrificed  in many  in-
stances  for  multiple uses of  the  surface  waters.
However, the  general feeling  was that many im-
provements  could be made  that  would improve
the waters for fish  production and  still  incorporate
multiple use.

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270
THE RELATION OF LAND USE TO THE AQUATIC ENVIRONMENT
        SOME ENVIRONMENTAL EFFECTS OF COAL AND GOLD MINING ON THE AQUATIC BIOTA

                                             A. D. Harrison*
                 INTRODUCTION

   Gold and coal mining  in South Africa, as in other
parts of  Africa, have marked  effects on  streams
draining the  mining areas.  These effects are of two
main types:   1. Silting.  This is particularly marked
in gold-mining regions where huge volumes of crushed
rock are  deposited  in  dumps  as fine  sand, and
powdered  ore  is  deposited  in  slimes dams  after
cyanide extraction.  2. Pollution by acid sulphates.
During  both types  of mining, when pyrite is exposed
to  air  and  water, it is oxidized by  bacteria into
ferrous and  ferric sulphate,  with or  without  free
sulphuric  acid.    In  coal  mining  this takes  place
mainly  in  the mine;  in gold mining most of the oxi-
dation takes  place  in the outer layers of mine  dumps
and slimes dams.    Water  from mines and  dumps
drains  into streams  and, although free acid is not
usually present, these effluents are usually highly
acidic,  the salts being hydrolyzed; pH values  of 2.3
or lower  have been recorded.  Kemp, 1962, recorded
acidities  of   314,  588,  and  750  ppm  as  CaCOs in
Natal  colliery  effluents,  and  10,700 ppm as  CaCOs
in a coal mine dump.

   Silt  from  mining operations  can have serious
effects  on streams and biota, but these are usually
localized.    Sandy  silt  soon settles and  fine  silt
flocculates in the  highly mineralized, acid  water.
Another form of silting arises from the oxidation of
ferrous  iron in the  effluents to  the ferric  state.
Insoluble   ferric compounds are precipitated  in  a
characteristic red or yellow deposit on the stream
bed.   The oxidation rate is greatly accelerated by
iron-oxidizing bacteria, so deposition usually occurs
along relatively short stretches of a stream.   In the
Witwatersrand gold-mining region  this process nor-
mally  is  complete before the  water reaches  per-
manent streams.    Where  this  is not the case, the
biota is  largely eliminated except for some  larger
plants such as Typha latifolia.


   In South Africa pollution by acid sulphates is a
major problem, especially as water remains highly
mineralized  after  neutralization.  The rate of acid
neutralization depends on the surface geology; in some
places  streams run through dolomite  or other  car-
bonate-rich formations and  the pH rises rapidly, but
in many  parts  natural carbonates  are not readily
available  and  strongly  acid conditions  persist for
many miles.

   Research in South Africa has been concentrated on
acid pollution and  the  subsequent contamination of
water supplies with neutral sulphates.
                                      EFFECTS OF ACID SULPHATE POLLUTION
                                                    ON THE BIOTA

                                  Polluted Streams With a pH Below 5.

                                     Two streams with a pH below,  or usually below,
                                  5  have been investigated.   The  first was the Klip
                                  River, near  Johannesburg, which  is polluted by run-
                                  off from  gold mines. It was studied not far from its
                                  source where, as a stream, it runs through a  swamp
                                  called Olifantsvlei.   Here  the pH went above 5 only
                                  once   during an  18-month study.  Conditions  are
                                  described in some  detail by Harrison, Keller,  and
                                  Dimovic,  1960.   The  other stream, the Klipspruit
                                  near   Witbank,  Transvaal,  receives acid  effluents
                                  from  coal  mines, and  is  reported on  by Harrison,
                                  1958.   A fuller  description is  to be published by
                                  Mr.  G.   Venter  of  the  Transvaal Provincial  Ad-
                                  ministration.


                                     Table  1  shows the chemical  quality of these  two
                                  streams  as well as that  of a mineralized but less
                                  acid  stream.   The  pH  of the  water  of the  Klip in
                                  Olifantsvlei was usually between 4.2 and 5.0; only two
                                  values were recorded outside this range, 5.9 towards
                                  the  end  of  a  dry season, and 3.7  during the height
                                  of a  wet  season.   The pH in the Klipspruit, Witbank,
                                  was  2.9  on two widely separated occasions;  during
                                  Venter's  study  the pH went slightly higher than this.

                                     The biological studies recorded here were carried
                                  out  well  below  the  main  region of silt deposition
                                  and  the  formation of ferric compounds.   Neither
                                  stream was subjected to scouring floods, so bottoms
                                  and banks  were  stable.   The biota was similar to
                                  that found in normal  dystrophic waters.

                                     Macrovegztation.   Table 2 gives the  more obvious
                                  macrovegetation of the  two streams, compared with
                                  that of the slightly acid to slightly alkaline Johannes-
                                  burg Klipspruit, a tributary of the  Klip River, which
                                  it joins in  Olifantsvlei,   The flora of  this tributary
                                  was fairly typical of unpolluted and slightly polluted
                                  streams  of the region.   The most obvious vegetation
                                  change in the acid Klip  was the absence of Lagaro -
                                  siphon major and its replacement by Scirpus fluitans.

                                     A characteristic  feature of  the two acid streams
                                  was  the  accumulation  of  undecayed  and  partially
                                  decayed  vegetable  matter in various  parts  of the
                                  stream bed.  Most of Olifantsvlei was a muddy swamp,
                                  but the section through which the  acid Klip flows has
                                  become a peat  bog;  in fact recent peat was being cut
                                  there.  The fern, Dryopteris thelypteris, was a char-
                                  acteristic plant on the bog.
 ^Zoology Department, University College of Rhodesia and Nyasaland.

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                   Some Environmental Effects of Coal and Gold Mining on the Aquatic Biota
                                              271
                                Table 1. WATER CHEMISTRY OF STREAMS

pH Wet season
Dry season
Total dissolved solids, mg/liter
Sulphates, mg/liter
Chlorides, mg/liter
Calcium, as CaCOs, mg/liter
Magnesium, as CaCOs, mg/liter
Turbidity, as Si02, mg/liter

Johannesburg
Klipspruit
5.2 to 6.8
6.1 to 7. 8
1,375 to 1,450
570 to 850
83 to 174
140 to 650
40 to 260
trace or
nil
Klip
3.7 to 4.3
4.0 to 5.9
930 to 1,530
405 to 1,660 a
18 to 115
290 to 650
125 to 300
nil

Witbank
Klipspruit
2.9
2.9
241 to 624
475
15


nil

          aTotal dissolved solids were not measured on this occasion.

                              Table 2. MACRO VEGETATION OF STREAMS

Sphagnum truncation
Dryopteris thelypteris
Typha latifolia
Paspalum sp.
Phragmites communis
Scirpus fluitans
Juncus exsertus
Juncus oxycarpus
Lagarosphon major
Polygonum lapathifolium
Ranunculus meyeri
Nasturtium officiarile
Crassula natans
Alisma plantago
Co tula coronopifolia
Johannesburg
Klipspruit
-
-
common
common
abundant
-
-
-
abundant
common
common
abundant
abundant
common
common
Klip
-
common
abundant
-
common
abundant
common
common
-
common
common
-
-
-
-
Witbank
Klipspruit
abundant
-
abundant
-
abundant
-
-
-
-
-
-
-
-
-
-
   The Witbank Klipspruit was very different in ap-
pearance  from nearby, unpolluted streams.  These
latter were fast flowing and of the trout stream type.
They  had  stony runs  and  stickles interspersed with
small pools  with  sandy or  slightly muddy  bottoms.
The  banks were fringed with small marginal reeds
and trailing grass; there was no true aquatic vegeta-
tion.  The Klipspruit, on the other hand, was much
overgrown by Phragmites communis and Typha lati-
folia  and  other reeds, and the bottom of its small
valley was becoming swampy  in  places.  Stream-
flow was impeded here and there by masses of partially
decayed vegetable matter; this and stones were covered
with  a  jelly-like  growth of  the  diatom,  Frustulia
rhomboides var. saxonia.  Deeper pools were floored
with a thick growth of Sphagnum truncatum.

   Strongly acid pollution does not eliminate macro-
vegetation and, although it discourages some species,
it may actually encourage others; communities include
some "acidophilic" species.
   Algae.   These were  studied only in the Johannes-
burg  streams.  Algal  growths were  less dense  in
the  acid  Klip than in  other  nearby  streams, but
common filamentous types were often found, such as
SphaerocysHs sp.,  Oedogonium sp.,  Mougeotia sp.
and Tribonema sp.

   The diatoms of the  Klip were studied in  some
detail  (Cholnoky, 1958,  and his notes  in Harrison,
Keller, and Dimovic, 1960).   Cholnoky found that the
diatom community of the acid  Klip consisted mainly
of acidobiontic  species,  Eunotia  exigaa,  Frustulia
magaliesmontana, Frustulia  rhomboides var. saxonia;
and  Pinnularia  acoricola-  the acidophilic species
Pinnularia subcapitata;  and  the  resistant species
Achnanthes  microcephala and  Achnanthes minutis-
sima.

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272
                      THE RELATION OF LAND USE TO THE AQUATIC ENVIRONMENT
   The fauna.   In Table 3, the fauna of the two Johan-
nesburg streams is  compared.  That of the slightly
acid to slightly alkaline Klipspruit was fairly typical
of a slow-flowing stream in the district.  The fauna of
the acid Klip was impoverished, consisting of wide-
spread species resistant to acid conditions.  Faunal
densities were somewhat lower than in normal streams,
but some  forms, such as the caddis Oxyethira velo-
cipes  and the oribatoid mite, Hydrozetes sp.,  were
sometimes more abundant than in normal streams.
This is not brought out by the percentage  composition
figures in the  table.   Note the lack of caenidae at
both stations.

   The  fauna  of the  acid  Witbank Klipspruit  was
greatly impoverished in  species, although the faunal
density was not particularly low.  Normal  streams
nearby contained representatives of most of the usual
aquatic groups and  families such as  Planarians,
Ostracoda,  Copepoda, river  crabs,  Hydrachnellae,
Baetidae,  Leptophlebiidae, Tricorythidae, Caenidae,
Heptageniidae,  several families of  caddis,  damsel-
flies,  dragonflies,   the   usual  families of aquatic
beetles, including Hydraenidae, Elmidae and Psepheni-
dae, Simuliidae,  Ceratopogonidae, and the  common
families of Chironomidae.    The fauna of the  acid
stream lacked  most of these and consisted mainly of
Hydrozetes sp.  and other oribatoid mites, the caddis
Oxyethira velocipes  and the chironomid Polypedilum
(Pentapedilum) anale.   Other species present were
Baetis  harrisoni,  Athripsodes  harrisoni   (Lepto-
ceridae)  and the chironomids  Chironomus  linearis,
Endochironomus di spar His, and  Tanytarsuspallidulus.
Venter will probably add to this list.

   No fish were found in  either of the acid  streams.

   The fauna of these strongly acid waters consisted
mainly, if not entirely, of fairly widespread species
that  are  resistant to acid conditions.  Most of those
recorded have  also  been  found in distinctly alkaline
waters.  Some, however, appeared to be more abund-
ant in  these acid waters,  which  could be due to lack
of competition.

   Harrison  and Agnew,   1962,   discuss the  fauna
endemic  to naturally acid streams flowing off quartz-
ites  in the Southern and Southwestern   Cape Pro-
vince,  South Africa.   There  is  a  whole  series of
species, mainly Ephemeroptera, Plecoptera, and
Trichoptera, as well as other  groups, which are re-
stricted  to  acid streams of the region with  a pH
fairly constantly below 6.0.  In nearby streams from
other geological formations, similar in  all respects
but with  a pH above 6.0,  these are  rare or entirely
absent and  are replaced by other species that are
widely distributed   over  Southern  Africa.    Some
widespread  species, however,  are common or  even
abundant in the acid  streams.

   The acid stream region  of  the Cape  Province is
too far from the polluted Transvaal streams for the
    Table 3.  FAUNA OF AQUATIC VEGETATION IN JOHANNESBURG ACID AND SLIGHTLY ACID STREAMS

Chaetgaster sp.
Nais sp.
Cyclops spp.
Paracyclops cf. poppei
Austrocloeon virgiliae
Enallagma glaucum
Anax imperator
Trithemis spp.
Orthetrum spp.
Athripsodes harrisoni
Ecnomus sp.
Oxyethira velocipesc
Pea pullula
Micronecta dimidiata
Dytsicid larvae
Culicini
Pentaneura spp.
Corynoneurinae
Tony tar sus -type larvae
Other Chironomidae
Bezzia-type larvae
Hydrozetes sp. (oribatoides)
Percentage composition
Klipspruit a> e
0.3 to 6.4
nil to 1.4
16.6 to 84.1
nil to 1.5
p to 6.6
0.1 to 2.2
nil to 0.4
nil to 0.2
nil to 0.4
rare
rare
0.2 to 3.9
nil to 1.7
0.2 to 2.9
occasional
occasional
nil to 8.3
3.8 to 23.6
nil to 1.9
3.7 to 42.5
occasional
occasional
Klipb
nil to 5.5
nil to 13.0
nil to 13.6
p to 6.3
-
p to 1.5
p to 0.1
-
-
occasional
occasional
0.6 to 25.2
-
-
-
occasional
-
0.5 to 3.3
occasional
17.3 to 90.0d
-
6.9 to 40.6
               apH 5.2 to 7.8; usually 6.5 to 7.0.
               bpH 3.7 to 5.9; usually 4.2 to 4.8.
               cGiven as Argyrobothrus sp. in Harrison, 1958, and Harrison, Keller, and Dimovic, 1960.
               dMostly Polypedilum (Pentapedilum) anale Freeman.
               eEntry p means present in very small numbers.

-------
                   Some Environmental Effects of Coal and Gold Mining on the Aquatic Biota
                                               273
endemic  species  to have  invaded them;  however,
some of  the more widespread species found in  the
acid Cape streams  are those  that have been able
to  colonize  the acid-polluted Transvaal  streams.
These  include  Austrocloeon virgiliae, Baetis  har-
risoni,  Enallagma  glaucum, Athripsodes harrisoni,
and Oxyethira velocipes.

   The chironomid_that  was most abundant in the acid-
polluted streams,  Polypedilum (Pentapedilum) anale,
has a scattered distribution over most of sub-Saharan
Africa.   Where  larval  habitats have been identified,
they have proved to be oligotrophic waters low in
or lacking bicarbonates with an acid  to  neutral re-
action,  or distinctly dystrophic waters. This chiron-
omid has been found in acid, polyhumic water at sea
level near Cape Town  (Harrison  1962), and in lakes
just below the  glaciers in the  Ruwenzori Mountains,
12,500  to 13,000  feet,  where  the  pH  is  about 4.5
(A.N. Adams, personal communication).

   Acid-polluted streams with a pH constantly below
5.0  have  a fauna impoverished  in species  but  not
necessarily of  a low density.  The faunal association
is characteristic and consists of resistant or tolerant
species and possibly a few that prefer acid conditions.

Slightly Acid or Fluctuating Conditions


   Table  1  shows  that pH conditions in the Johannes-
burg Klipspruit fluctuated  somewhat,  as acid from
gold  mines higher  upstream  were  sometimes  not
completely  neutralized.  The  pH seldom fell below
6.0,  however,  and the  fauna  and flora were more
or less normal  for the region, although the sampling
station was near the end of a region of recovery from
sewage  works pollution.  The diatom flora contained
acidophilic elements but not acidobionts.

   At a station below  the junction of the acid Klip
and Klipspruit,  conditions fluctuated slowly during the
survey  period,  and, after heavy rains during January
and  February 1955, the pH remained below  6.0  but
above 5.0 for some months.  This  led to a dying off
of thick growths of  Potomogeton pusillus and a drop
in faunal  density.   The  species  composition became
somewhat impoverished, but the typical associations
of a strongly acid stream did not  develop.  During
the  same period,  thick growths of  Ulothrix sp. ap-
peared  and died off periodically; however, not enough
pH readings were taken to be able to correlate  the
death of  the algae  with pH figures.   The fauna of
stony runs, normally dense at this station, became
very  sparse.    Caddis,  such  as  Cheumatopsyche
afra and  Macronema sp.,  and Simulium spp.  were
present in  very small  numbers for a  few  months
but finally disappeared.  They returned after the pH
had been above 6.5 for 2 or 3 months.

   Oliff,  1963,  describes conditions  in  Natal coal
fields.   Here again  acid sulphates were produced,
but were neutralized rapidly by carbonates in surface
rocks and soils.   There were  no long,  permanently
acid stretches  of  stream below  the deposition sites
of silt and ferric compounds.  Short stretches, where
the pH was acid during the wet season and alkaline
during the dry,  had  practically no  fauna  at all.
Conditions here were probably made worse, however,
by scouring floods.

   Slightly acid conditions, i.e.,  pH values from 6.0
to  7.0,  apparently  have little  effect on  the  biota
except on  the  composition of  some  algae such as
diatoms,  even  if  the pH drops for short periods of
a  week  or so into  the  5.0 to 6.0 range.  Prolonged
drops into the  5.0 to 6.0 range produce most marked
effects.
Effects after neutralization

   After neutralization of acid sulphates, the streams
in the  mining regions carry large concentrations of
the sulphates of calcium and magnesium.   Sulphate
values of over 1,000 milligrams per liter have been
recorded.   This  type  of  pollution is  very  im-
portant since many, if not all, of the streams run directly
into  public water supplies.  Large concentrations  of
neutral sulphates  have  no detectable effects on bio-
logical  associations, however,  at least in  the con-
centrations recorded in South Africa.

   The  Johannesburg Klip River  and similarly pol-
luted  streams find their way eventually into the Vaal
River; this major river is the water supply of Johan-
nesburg and many surrounding towns. Although most
of the  water of the  Vaal comes from a higher catch-
ment,  such factors  as a large storage dam higher up
and  irregular   rainfall  distribution result in dis-
proportionately  large  contributions from mine-pol-
luted  tributaries at  certain times.  This  raises the
total dissolved-solids content appreciably.  Normally
the Vaal  River water  is turbid at all times of the
year owing to extremely fine silt in suspension.  This
shows very little tendency to flocculate and it retards
the growth of planktonic  algae  and the animals that
feed on them.   The effect of the mineral pollution is
to bring about considerable flocculation. This allows
unusual growth  of plankton, which is most noticeable
where  the river  is  held back by a large barrage.

   Oliff,  1963,  dealing with Natal streams, reports
increased algal growth below the neutralization zone.
He considers this  is due  to nutrient salts coming
from  the coal  mines.   The increased algal growth
leads to increased faunal density and certain changes
in the species composition, rather like those found
towards  the  end of a  "beta  mesosaprobic" zone.

   Neutral sulphates, in the concentrations found  in
South African  streams, i.e.,  not much higher than
1,000  milligrams  per  liter,  have  little  noticeable
effect on  the biota.   The only exceptions  are where
they result in  abnormal clarity of water with in-
creased  algal   growth  and related changes.   The
growths may be assisted by nutrient salts from coal
mines.

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274
THE RELATION OF LAND USE TO THE AQUATIC ENVIRONMENT
                                             REFERENCES
Cholnoky, B.J.,  1958.  Die Diatomeenassoziation des
Sumpfes Oilifantsvlei sudwestlich Johannesburg. Ber.
dtsch. bot. Ges.  71 (4): 177-187.


Harrison, A.D., 1958.  The effects of sulphuric acid
pollution  on the biology of streams in  the Trans-
vaal,  South  Africa.  Verh.  int.  Ver. Limnol.  13:
603-610.


Harrison, A.D., 1962.   Hydrobiological  studies  on
alkaline and acid still waters in the Western Cape
Province. Trans. Roy. Soc. S. Afr. 37 (4).

Harrison, A.D.,  and Agnew, J.D., 1962. The distribu-
tion of invertebrates endemic to acid  streams in
                                 the  Western  and  Southern  Cape  Province.
                                 Cape Prov. Mus. 2: 273-291.
Ann.
                                 Harrison,  A.D., Keller, P., and Dimovic, D.,  1960.
                                 Ecological studies on Olifantsvlei, near Johannes-
                                 burg. Hydrobiologia 15 (1-2): 89-134.


                                 Kemp, P.H., 1962. Acidic drainage from coal mines
                                 with special reference to the Natal  coal fields. South
                                 African  Council  for  Scientific and Industrial Re-
                                 search, Special Report No. W 12.

                                 Oliff, W.D.,  1963.   Hydrobiological studies on the
                                 Tugela River  System.  Part IV.  The Buffalo River.
                                 Hydrobiologia, in press.

-------
                       The Effects of Stream Sedimentation on Trout Embryo Survival
                                              275
             THE EFFECTS OF STREAM SEDIMENTATION ON TROUT EMBRYO SURVIVAL

                                            John C. Peters*
                 INTRODUCTION

   Small quantities of sediment are introduced con-
stantly  through  the entire course of  a stream by
geological  processes  and have little  effect on the
aquatic  communities occurring normally within the
stream.    The  introduction of gross  quantities of
sediment into streams changes the quality and quantity
of lotic aquatic life.  Agricultural practices responsible
for the  addition of gross quantities of sediment into
streams are:   (1) Overgrazing range land,  (2) brush
and tree removal on the floodplain and along stream
banks,  (3)  snag  removal  and channel realignment,
(4)  row crop  production on  steep sloping land,  (5)
overgrazing floodplain land,  and (6)  surface  irri-
gation return water.

   The  addition  of  gross quantities  of  sediment
changes the community  of aquatic organisms  within
a stream and  diminishes the total productivity of the
stream  (Cordone and Kelley,  1961).  Trout or other
sport fishes disappear and less desirable  fish replace
them in the stream community complex. Bottom fauna
and fish production are  reduced in streams carrying
large  sediment  concentrations through  the   entire
year.

   Clean,  permeable  gravels provide the  nursery
areas in the stream environment for trout embryos.
In the process of redd  construction, sediments are
cleared from the gravels by the spawning female be-
fore the eggs  are  deposited.  The fertilized eggs
develop in an environment well protected from preda-
tors.  Water seeps through the gravels into the redd
delivering  oxygen  to  the  developing trout embryos
and washing away metabolic waste products produced
by the embryos.

   The  suspended  sediment present during the in-
cubation period  can greatly affect the  survival rate
of developing trout embryos.  In a stream with large
sediment concentrations, sediments will be deposited
in trout redds,   clogging the  pore  spaces  between
the gravels.  Consequently,  the  seepage  rate  will
decrease and  the supply of oxygen to the  redd will
diminish.

   Continuous   large sediment concentrations   in  a
stream  during the  trout egg  incubation period can
determine the recruitment of young-of-the-year trout
to the population.  Without high yearly recruitment,
the trout population can be  replaced by a species
whose needs are better  supplied by the environment.

   This report of our investigation of Bluewater Creek,
a stream greatly influenced by agricultural practices
in  its lower  reaches, considers  the  relationships
between  stream discharge and  sediment concentra-
tions  and their subsequent effects on the intragravel
apparent  velocity  (seepage  rate)  and  intragravel
oxygen  supply to  the developing  trout embryos.

                    METHODS

   Sediment concentrations and discharge were meas-
ured at five sampling stations in Bluewater  Creek,
Montana, by standard methods used by the Geological
Survey.   The  Department has  a cooperative  agree-
ment  with the Quality of  Water Division of the U.S.
Geological Survey  in  Worland,  Wyoming, to  collect
these  records.  Methods used for sampling suspended
sediment  are found in reports by the Federal Inter-
Agency River Basin Committee (1940,1941). Stream-
gauging procedure  to measure  discharge  is sum-
marized  by Corbett (1943).  Sediment  concentration
is defined as the  weight of sediment in  a water-
sediment  mixture to the  total weight of the mixture
and  is ordinarily  expressed in parts per  million
(ppm).   Discharge is defined as the rate of flow at
a given instant and is ordinarily expressed in cubic
feet per second (cfs).

   In  the vicinity of the  sediment-discharge  samp-
ling stations, man-made  redds  were constructed by
excavating a hole in the  streambed approximately 3
feet long, 2 feet wide, and 1 foot deep.  The excava-
tions  were filled with 3/8-inch sorted gravel chips
and allowed to  stabilize   for  1 week before  eggs
were placed in the redds.

   Eyed  rainbow trout eggs were  counted,  poured
into Vibert boxes (Anon., 1959) partially filled with
gravel chips, and placed in the redds. At each samp-
ling station, two Vibert boxes  with 200 eggs per box
were  placed 7 inches  deep within the  redd.   The
developing embryos were allowed to  remain in the
stream until 1  week after calculated hatching time.

   Mortality is defined as the  ratio of the  number
of dead  embryos  remaining in the Vibert boxes to
the total number of eyed rainbow eggs placed in the
egg-hatching box.

   The Mark  VI standpipe apparatus  was used to
measure the intragravel  dissolved oxygen and intra-
gravel apparent velocities within the redds contain-
ing the  developing rainbow trout embryos.   The
theory and  application of this  standpipe are found
in  Terhune (1958).   Intragravel  dissolved  oxygen
determinations were measured with a microtechnique
of the Winkler method (Harper,  1953).
*This study was partly financed and administered through Federal Aid, Dingell-Johnson Act (Project F-20-R, Montana).
  Montana Fish and Game Department, Billings, Montana.

-------
276
THE RELATION OF LAND USE TO THE AQUATIC ENVIRONMENT
Description of the Study Area
   Bluewater Creek is a spring-fed stream approxi-
mately  15 miles  long,  flowing  in a  northwesterly
direction  to  its confluence with the  Clarks Fork of
the  Yellowstone  River  near Fromberg,  Montana.
During  the irrigation  season, little water is diverted
from the  creek in the upper  6  miles.   Irrigation
demands,  diverting water from the creek, and irri-
gation surface and subsurface returns,  greatly change
the quality of water in the lower 9 miles  of the stream.
During the winter  months (November through March),
fluctuations in flows are small.

Experimental Design
                                     Th3 monthly  average sediment concentrations for
                                  the five  sampling  stations  are shown in Figure  2
                                  and Table  1.   The monthly average sediment con-
                                  centration was smallest at the upstream station (I) of
                                  Bluewater  Creek.   Proceeding downstream,  the
                                  monthly  average sediment  concentration increased
                                  progressively at  the  next  two sampling stations
                                  (II and III).   At  sampling Station V near the creek's
                                  confluence  with  the  Clarks Fork of  the Yellowstone
                                  River, during November  and December, the monthly
                                  average  concentration was  less than at Station IV.

                                     In  January, starting at the  upper  station and pro-
                                  ceeding  downstream  to  the lower  sampling  area,
                                  the monthly  average  sediment concentrations  in-
                                  creased progressively.
   Sampling  sites in the study stream were chosen
so that comparisons could be made between stations
with small sediment concentrations  and  stations af-
fected by progressively  larger sediment concen-
trations.   The  five sampling stations  were located
at intervals  of about  3 miles  and numbered  con-
secutively I  through  V; with I  denoted as the up-
stream station, V the downstream station.
                     FINDINGS
   In the winter months, when no water is diverted
from the stream for irrigation, the daily  mean dis-
charge at all five  sampling  stations  showed little
fluctuation (Figure 1).   The greatest change between
consecutive  days  in  daily mean discharge  was  2
cubic feet per second.
    15

    10

    5

    35
 tfl
t;  so

o  25
cu

s  3*
¥2  30
o
z  zs
LU
S  35
>-
J  30

Q  25

    35

    30

    25
     23-
                                     Sediment  concentrations  at the upper station  on
                                  Bluewater  Creek were small, with  20 ppm as  the
                                  largest monthly  average  concentration.   This was
                                  roughly one-fifth of that at the next station down-
                                  stream (II).   A  comparison of the monthly average
                                  sediment  concentration at Station I with the  other
                                  sampling stations shows that the  concentrations were,
                                  at most,  for Station  HI,  17 times  greater; Station
                                  IV, 22 times  greater; and Station V, 24 times greater.
                                  The  sediment concentrations in Bluewater Creek can
                                  be characterized as increasing  progressively down-
                                  stream.

Q.
a.
0
1-
CONCENTRy
i-
LU
0
LU
oo
HLY AVERAGE
1-
o
~*


360
360
340
320
300
280
260
240
220
200
ISO
160
140
120
100
eo
60
40
20

Station IV
n
1 j
~ 	 - Station V



_ Station III

1
_ 	 / Stotlon II











-
-
-
Stotion 1

23 1 1 || 19
 Figure 1.  Daily  mean discharge from five sampling stations
          in Bluewater  Creek from November 23, 1961, to
          January 19, 1962.
                                   Figure 2. Monthly average sediment concentrations from five
                                           sampling stations in Bluewater Creek from Novem-
                                           ber, 1961,through January, 1962.

-------
                       The Effects of Stream Sedimentation on Trout Embryo Survival
                                              277
                Table 1. MONTHLY AVERAGE SEDIMENT CONCENTRATIONS AND RANGE
                       OF OBSERVED CONCENTRATIONS ESf BLUEWATER CREEK
Month
November

1961



December

1961



January
1962




Monthly
average

Range of
observed
concentrations
Monthly
average

Range of
observed
concentrations
Monthly
average

Range of
observed
concentrations
Sediment concentration, ppm
Station
I
20



9 to 67

13



8 to 26

16


12 to 25

II
97



61 to 166

118



59 to 203

147


71 to 363

m
174



115 to 389

142



69 to 199

276


172 to 486

IV
328



249 to 481

282



55 to 884

343


221 to 506

V
254



196 to 427

246



79 to 511

386


61 to 1,240

   The  great  variation  occurring  in daily  mean
sediment concentrations further describes the deteri-
oration  in water  quality in  the downstream areas in
the creek.   The sources of sediment with relatively
stable flows are thought to be: Runoff occurring on
warm days, lateral erosion of the streambanks, ice
gouging of  the  streambanks and  streambed, and de-
gradation of the streambed.  Little variation in daily
mean sediment concentration  implies that a stream
in a steady state of operation would neither aggrade
or degrade but transport the load supplied to it through
the system  without change in vertical position of the
bed  and without  change in transverse form  of the
bed or  the channel (Strahler, 1956).  Bluewater  Creek
is  relatively  stable  at the upper  station  (I) with
sediment  concentrations ranging from 9 ppm to 67
ppm  in November.   In January, the concentrations
at the lower station (V), an unstable area of the stream,
ranged  from 61 ppm  to 1,240 ppm.  The progressive
downstream deterioration in the  creek, as indicated
by great variation in daily  sediment concentrations,
points out relative  stability in the upper areas com-
pared with great instability in the lower areas.
   The  Mark  VI standpipe apparatus  was  used to
measure intragravel  apparent  velocity  and  intra-
gravel  oxygen  concentration in  redds  placed  in the
vicinity of  the sediment-sampling stations.  A stand-
pipe was driven into  a redd constructed  of 3/8-inch
gravel chips and removed after each series of meas-
urements.
   The  apparent  velocity  is  laminar flow of water
through the streambed gravel  and  is often  called
the seepage rate,  the  volume of liquid flowing per
unit time through a  unit area normal to the direc-
tion of flow.   A high rate of  seepage  is required
to deliver   oxygen  to the  salmonid embryos and to
carry away metabolic waste products  (Coble,  1961).
  In the  stable upper area of the stream with small
sediment concentrations, the apparent velocity through
the  man-made redds remained high during the entire
study period (Figure  3).  At the start of the study,
the  apparent velocities  in each of the redds were
within  5  centimeters  per  hour of each  other.  A
marked progressive  rate of decrease in apparent ve-
locity was measured  at each successive  sampling
site.   After 12  days at the lower sampling station,
the  apparent velocity  dropped from 85 to 25 centi-
meters  per  hour.   No  change occurred  in the ap-
parent velocity  at Station  I  during  the  same  time
period.
  Large concentrations of intragravel dissolved oxygen
are required for salmonid embryo survival (Wickett,
1954 and Coble,  1961).   At the start of the study,
the  dissolved-oxygen concentration in four of the five
redds was 8,1 ppm; in the remaining redd at Station
V, the  dissolved-oxygen concentration was 7.9 ppm.
The  rate  of decrease  in dissolved-oxygen concentra-
tions is  shown  in Figure 4,  which illustrates  pro-
gressive downstream deterioration in the redds.  The
least dissolved-oxygen  deterioration occurred at
Station I  with a decrease  of  0.7 ppm.  At the lower
two sampling stations the dissolved-oxygen deteriora-
tion  was  the greatest with a  1.7 ppm decrease at
Station IV and 1.5 ppm decrease at Station V.
   The average dissolved-oxygen concentrations also
describe the progressive downstream deterioration in
the  creek (Table 2).  The upper areas of the  stream
with relatively small sediment concentrations and high
intragravel  apparent  velocities have large average
intragravel  dissolved-oxygen  concentrations. Large
average intragravel dissolved-oxygen concentrations
are found in the downstream redds affected by high
sedimentation rates  and  low intragravel apparent
velocities.

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278
THE RELATION OF LAND USE TO THE AQUATIC ENVIRONMENT
                                                       Of.
                                                       u
                                                       8
                                                       o
                                                       >-  9
                                                       X
                                                       o
                                                                 Dote eqqs  in
                                                                                            Dole eggs outl
                                                         Figure 4. Intragravel oxygen  concentration at  five sampling
                                                                stations  in  Bluewater Creek from  November  23,
                                                                1961, to January 8, 1962.
 Figure 3. Intragravel apparent velocity at five sampling sta-
         tions  in Sluewater Creek from November 23,1961,
         to January 8, 1962.
    Table 2. TROUT EGG MORTALITY COMPARED WITH INTRAGRAVEL OXYGEN CONCENTRATIONS
                              AND INTRAGRAVEL APPARENT VELOCITIES
Station
Number
I
n
m
IV
V
Mortality, %
5
39
90
100
100
Oxygen concentration, ppm
Average
7.8
7.8
7.6
7.3
7.1
Range
7. 4 to 8.1
7.3 to 8.1
7.1 to 8.1
6.4 to 8.1
6.4 to 7.9
Apparent velocity,
cm/hr
Average
82
61
43
21
23
Range
75 to 90
55 to 85
15 to 85
5 to 90
10 to 85
   The mortality of rainbow trout embryos is related
to the average intragravel oxygen concentration and
the average  apparent velocity (Table  2).   Only  5
percent of the rainbow trout embryos failed to sur-
vive at Station I.   Mortality increased progressively
at the next two downstream  sampling stations.  No
embryo survival was found at the two lower stations
in the stream.
                                                      DISCUSSION

                                     Bluewater  Creek,  during the  study  period, was
                                  characterized  as a stream with  little fluctuation in
                                  discharge.   There  was  a progressive  downstream
                                  increase  in  sediment  concentrations  at  the  five
                                  sampling areas in the stream.  Man-made redds filled
                                  with 3/8-inch gravel chips were placed in the vicinity
                                                                                                GPO 816-361 — 10

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                        The Effects of Stream Sedimentation on Trout Embryo Survival
                                              279
of each  sediment-sampling  station.   Each redd, at
the  start  of  the  study, had almost identically large
intragravel dissolved-oxygen concentrations and intra-
gravel apparent velocities.The intragravel dissolved-
oxygen concentration rate and apparent velocity de-
creased progressively downstream in relation to the
progressive  downstream increase in  sediment con-
centration.    Accompanying  the progressive down-
stream decrease in intragraveldissolved-oxygen con-
 centrations and intragravel apparent velocities was a
 progressive  increase  in  trout  embryo  mortality.
   Sediment passing a  given  area of  a  stream can
 greatly affect trout embryo survival. Small sediment
 concentrations with  small fluctuations in discharge
 in a  stable streambed environment indicate a stream
 area  with  a. potential for good trout embryo survival.
                                             REFERENCES
Anon. 1959.  Plastic hatching box  for stocking trout
and salmon.  Prog. Fish. Cult., 13:  228.


Coble, D.W.  1961.   Influence of  water exchange and
dissolved oxygen in redds  on survival of steelhead
trout embryos.  Trans. Am. Fish.  Soc., 90: 469-474.

Corbett,  D.M.,  et.  al. 1943. Stream gauging proce-
dure.   U. S. Geol.  Surv.  Water  Supply  Paper No.
888. 225  p.


Cordone,  A.J.,  and D.W.  Kelley.    1961.   The in-
fluences  of inorganic sediment  on  the aquatic  life
of streams.   Calif.  Fish and Game., 47: 189-228.

Federal  Interagency River Basin Committee.  1940.
Measurement and  analysis  of  sediment  loads in
streams.  Report No. 1.   Field  practice and equip-
ment used  in  sampling  suspended  sediment.  St.
Anthony  Falls  Hydraulic Laboratory.  Minneapolis,
Minn. 175 p.
Federal  Interagency River  Basin Committee.  1941.
Measurement and  analysis of  sediment  loads in
streams.   Report No. 3. Analytical study of methods
of sampling  suspended  sediment.   St. Anthony Falls
Hydraulic  Laboratory.    Minneapolis, Minn.  81 p.

Harper,  E.L. 1953.  Semimicrodetermination of dis-
solved oxygen.  Anal. Chem., 25: 187-188.

Strahler, A.N.  1956.  The nature of  induced erosion
and  aggradation, p. 621-637.  In  W.L.  Thomas Jr.
et.  al.  (ed.), Man's role in  changing the face of the
earth.  Univ. Chicago Press, Chicago.

Terhune,  L.D.B. 1958.   The  Mark  VI  groundwater
standpipe  for  measuring seepage through salmon
spawning gravel.   J.   Fish. Res.  Bd. Canada., 11:
1027-1063.

Wickett, W.P.  1954.   The oxygen supply to salmon
eggs in spawning beds.  J. Fish. Res. Bd. Canada.,
11: 933-953.

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                      THE CONTROL OF FISH DISEASES AND PARASITES

                                         S. F. Snieszko, Chairman*

                       THE CONTROL OF BACTERIAL AND VIRUS DISEASES OF FISHES

                                              S. F. Snieszko
   Infectious diseases of lower and higher vertebrates
are similar in many respects and are caused by the
same types of agents, such as viruses, bacteria, fungi,
and protozoan and metazoanparasites. For this reason
control of communicable fish diseases is based on the
same general principles as in all vertebrates.

   There are, however, two very important differences
in the approach to the  study of fish diseases.  One is
that  fish live in water and breath oxygen  dissolved
in water,  instead of oxygen  from the air.   There is
about 21 percent oxygen in the air,  but the concen-
tration of oxygen dissolved in water varies greatly.
Sometimes fishes are exposed to water supersaturated
with oxygen; this may result in fatal gas embolisms.
At other times the lack of oxygen causes asphyxiation.
Often the same body of water may be supersaturated
with oxygen during the day and almost free from it at
night.  Since fish are poikilothermal, temperature is
not  only  a  limiting  factor in  fish  survival,  but
variation  in  temperature affects the  rate  of  fish
metabolism,  growth, production  of  antibodies,  and
the degree of resistance to pathogens and parasites.
Considerable  and frequent variation in the  physical
and  chemical   environment  in which fish live  also
has  a very far reaching and still  inadequately ap-
preciated  influence on  the incidence of diseases and
effectiveness of control measures,  as well as on the
degree of  side  effects of  drugs and disinfectants.
There are  also  species-specific  differences  in  the
sensitivity  of fish  to various chemical agents.   All
this  must  be kept in  mind when  discussing control
measures for communicable fish diseases.

   In conducting bioassays with fish, there are frequent
difficulties  caused by  columnaris disease and pro-
tozoan and metazoan parasites.  Fish used for assays
are often infected or parasitized, and the methods of
control are still inadequate. Even though some of these
infections  are  apparently  not very harmful,  they
do introduce possible variables.

   Starting with virus diseases, I should like  to talk
first  about lymphocystis and fish pox of warmwater
and  aquarium fishes.   Both  diseases can be  easily
diagnosed by microscopic examination.  Both produce
hyperplasia of  epithelial cells,  are seldom fatal,
and under natural conditions occur during the summer.
Most of the fish recover by fall.

   Salmonid fishes are often subject to acute systemic
virus diseases that cause heavy mortalities in young
fish.  The  most important are  infectious pancreatic
necrosis,  virus  diseases  of Chinook  and  sockeye
salmon, and liver-kidney  syndrome of rainbow trout.
Etiology of the last disease is still disputed.  There
is no treatment known for virus diseases of fishes.
The only control  measures are sanitation, isolation,
and selection of healthy brood fish.

   Bacterial diseases  of  fishes are very common.
Probably the most frequent are infections caused by
Aeromonas  liquefaciens   (many  synonyms)  and
Pseudomonas fluorescens.  These bacteria may cause
local  lesions,  necrosis,  and  systemic  infections.
Mortality rate is high, and fish may have latent in-
fections that flare up when the fish are exposed to
stress.    Diagnosis  is possible only by bacterio-
logical identification of the pathogens.

   A. liquefaciens and P.  fluorescens are ubiquitous
waterbacteriabutonly cause diseases and losses among
fishes with lowered resistance.  German and Russian
investigators suspect  viral infections to be the most
important  predisposing factors.  Other investigators
attach more significance to environmental factors, as
well  as  to bruises  and  stress  caused by rough
handling. Chemotherapy is usually effective in control
of  these infections.  Chloramphenicol, tetracycline,
and oxytetracycline given orally at a rate of 50 to
100 mg/kg/day are very effective.  Nitrofurans are
very  promising.   Sulfapyrimidines  given  orally at a
rate  of 100  to  200  mg/kg/day  usually are  also
beneficial.   Unfortunately, reinfections occur readily
unless  stress  conditions  are   corrected.  Very ef-
fective  prophylaxis lasting for 1 to 2 weeks  can be
achieved by a single  intraperitoneal injection of
Chloramphenicol, tetracyclines, and streptomycin at a
rate of 10 to 20 mg/kg.  Chloramphenicol succinate,
which is readily soluble,  seems to be toxic to fishes
when injected  intraperitoneally.  Sanitary measures ,
uncrowded conditions, clean water,  sufficient oxygen,
and optimal temperatures are  the best preventive
measures.

   Furunculosis is a systemic bacterial disease that
most frequently affects salmonids. From salmonids
it may be transmitted to warmwater fishes and cause
rapidly progressing epizootics with  a very high, often
complete,  loss of infected fish.  It is caused by A.
salmonicida.   Positive diagnosis is possible only by
identification of the pathogen.

   Treatment and prophylactic measures are the same
as  for  infections caused by A. liquefaciens and P.
fluorescens.  One of the best  long-range preventive
measures  against the  above described  diseases is
selecting and breeding resistant fish.
 * Bureau of Sport Fisheries and Wildlife, Eastern Fish Disease Laboratory, Leetown (P.O. Kearneysville), W. Va.
                                                    281

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282
THE CONTROL OF FISH DISEASES AND PARASITES
   Very important and common bacterial fish diseases
are caused by myxobacteria. Gill disease is the most
common  in  salmonid fishes.  It is  characterized by
superficial infection of gills resulting in hyperplasia
of gill epithelium,  fusing and clubbing of gills. This
results in distress  caused by respiratory difficulties.
If not  checked in time, gill disease usually results in
gill necrosis and death.  This  seems to be a typical
stress disease because its occurrence is associated
with crowding and accumulating nitrogenous waste
products.   The best prophylactic measure  is clean,
well-oxygenated water of optimal temperature. Treat-
ment and prophylaxis  can  be accomplished by 30 to
60 minute exposure to quaternary ammonium disin-
fectants as  Roccal or Zephiran, or to organic mer-
curials as pyridylmercuric acetate of ethylmercury-
phosphate  (Lignasan  X).    All these  disinfectants
are used in concentrations of 2 ppm calculated on the
basis  of active undiluted  compound.   Lignasan X,
containing  only about  6 percent active ingredients,
however, is used only at a rate of 1 to 2 ppm of the
product as is, and not on  the  basis of the active in-
gredient.    Mercurials  are very toxic to rainbow
trout.

   Columnaris disease is  the  other  common myxo-
bacterial disease of cold and warmwater  fishes.  It
can produce different types of external lesions, ulcers,
necrosis, and systemic infections.   (Crowding, pol-
lution, and increasing water temperature seem to be
the most important stress factors.)  The  causative
bacteria  can be easily identified by their morphology
and  characteristic oscillating and sinuous motility.
Antibiotics  such as chlortetracycline and  oxytetra-
cycline are very satisfactory for control of external
columnaris  disease in aquarium fish when added to
water  at  a rate of  20 to 60 ppm.  In systemic in-
fections sulfonamides are helpful. Recently completed
in vitro  studies indicated  that nitrofurans  and other
antibiotics may be of use in the treatment and control
of this disease.
   Kidney disease  and mycobacterioses are also im-
portant bacterial diseases.   Kidney disease is common
among salmonid fishes and perhaps some tropical
species.   The  etiological  agent is an  incompletely
described but very  fastidious corynebacterium. Diag-
nosis  is made on  the basis of gram positive diplo-
bacilli in smears prepared from the lesions. Erythro-
mycin given orally at a rate of 100 mg/kg/day is the
most effective drug.

   Mycobacterioses are common among  aquarium
and  marine  species of fish.   They usually cause
chronic,  systemic  infections with  multiple  foci  in
visceral  organs.   In  advanced cases mycobacteria
are extremely abundant in tissues, and their presence
can  easily  be  demonstrated   in  acid-fast  stained
smears.   The infected fish are stunted  and often
unable to reproduce, and the disease ends in death.
Therapeutic  measures are  still unknown.   Trans-
mission  occurs,  most likely,  from fish to fish and
can  easily  be accomplished by  feeding tissues  of
infected fish.

   This brief survey has shown that there  are num-
erous  bacterial and viral  fish  diseases.  Some can
                            produce rapidly spreading epizootics with high, some-
                            times  total,  losses.    Diagnosis  is usually easily
                            accomplished by isolation and identification of the
                            pathogens.   Some external and internal therapeutic
                            measures are effective, and prophylaxis with drugs is
                            often practicable.


                               The most important control measures are sanitation
                            and  removal of  stress  conditions.   A very effective
                            approach  to  the  control  of  some infectious fish
                            diseases  is selecting  and breeding resistant  fish.
                            This  has  been  done  successfully  in a number  of
                            cases in Europe and the United States.   The brood
                            fish  selected had survived  without apparent  harm
                            a natural or artificial epizootic. In the next generation
                            fish used for breeding were challenged by inoculation.
                            Again the fish that were selected had survived without
                            disease  symptoms or  were  only  lightly diseased.
                            These were used as brood stock.  By such a simple
                            procedure it was possible to select and breed trout
                            resistant to furunculosis and ulcer  disease and carp
                            resistant to hemorrhagic  septicemia.   All three are
                            common bacterial fish diseases.


                               Fish are  also  subject  to neoplastic diseases.
                            Almost any type of tumor found in  higher vertebrates
                            has  a counterpart in  fishes.   Recently  hepatoma in
                            rainbow trout  reached pandemic  proportions.   In
                            some  hatcheries and  in some lots  of rainbow  trout
                            the  incidence of hepatoma was close to 100 percent.
                            In brook trout raised in hatcheries there is a common
                            visceral  granuloma of  unknown etiology.  It causes
                            heavy losses among 2-  and 3-year-old trout.


                               One must remember that, so far, there are  no
                            sources for obtaining  fishes  reasonably free  from
                            communicable  diseases. Fish that have viral and/or
                            bacterial or infectious  diseases, latent  infestations,
                            and  neoplastic  or nutritional diseases and that are
                            genetically heterogenous  are hardly   suitable  for
                            communicable   diseases research,  toxic  chemical
                            assays, or other investigations.

                               In contrast there are commercial and other sources
                            for  obtaining healthy and  genetically uniform white
                            mice, rats, rabbits,  guinea pigs,  and other animals.
                            With  the  rapidly  increasing interest  in  fishes  as
                            experimental animals,  it would be  most desirable
                            if a fish  breeding institution could be established
                            from  which  to  obtain  healthy  experimental  fish.
                            Such fish should be reasonably free from bacterial,
                            viral, and parasitic diseases.  They should be main-
                            tained  under well-standardized  conditions  and fed
                            diets to prevent malnutrition.  Perhaps with the co-
                            operation  of federal,   state,  university, and  com-
                            mercial laboratories that use fish for experiments and
                            bioassays,  such fish hatcheries could be established
                            and  maintained.   I would  like  to suggest the organi-
                            zation of a committee  to  investigate the desirability
                            and  other aspects of creation and operation of such an
                            institution.

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                                       The Control of Fish Parasites
                                               283
                                     THE CONTROL OF FISH PARASITES

                                             Glenn L. Hoffman*
   As stated  in the preceding paper, healthy fish are
desired   for   experimental  work  in  bio-assays  of
pollution, in fish  physiology  and nutrition,  chemical
fish control,  insecticide assays, and  fish  diseases.
Parasitic infection is  one  of the many  variables  to
be avoided in  such experiments.


   The parasites  of fish belong  to  several taxons
but, for convenience, we often  categorize  them ac-
cording  to  their  location  on or in the fish.  In his
1953  text, Dr. H.  S. Davis divides the parasites into
external  and  internal  parasites.   This  terminology
is  particularly useful  in the case of the treatment
of ectoparasitic diseases because certain methods are
effective  for  several  groups of external parasites.

   The life  cycles of the parasite  should be kept  in
mind  as  this  may influence  the type  or time of at-
tempted parasite control. In general, the fish parasites
follow these patterns:


   1.  Ectoparasitic protozoa  - most of  these  divide
by  binary fission, a few by internal budding (Trich-
ophrya)  and one by  division  within a  cyst  (R'.ithyo-
phthirius).  Typical  protozoan cysts are not formed
or  are unknown  for others.    Infection  is direct,
from fish to fish or by contaminated equipment. The
amount of damage to skin and gills is usually related
to the  number of parasites present.

   2.  Internal protozoa — some  live in the  intestine
and divide by binary fission  and also produce  cysts.
Infection  is probably accomplished by cysts.  Others
live in tissues and divide  and produce a mass  of
spores that is usually visible to the naked eye.  Fish
may be  infected by  ingesting spores that are freed
from other  fish.   The  protozoa  that live in  the blood
stream divide by binary fission and are transferred
from fish to fish by leeches in  which they  multiply.
Damage  to the fish ranges from negligible  to fatal.

   3.  Monogenetic  trematodes — except  for Gyro-
dactylus,  which is viviparous, these lay eggs  that
soon  hatch;  fish  infection  is from these  larvae  or
adults from adjacent infected fish or contaminated
equipment.  Heavy infections  may  overwhelm  small
fish.

   4.  Digenetic trematodes — all of these have a snail
intermediate host; fish may become infected by larval
stages that escape from the snail or  from eating
other  infected  intermediate   hosts such  as larval
insects, small fish, etc. Most  of these are not serious
pathogens, but large numbers of cercariae  may kill
fish.   The eggs of blood flukes may plug  so many gill
blood vessels  that the fish may be killed.
   5. Cestodes — intermediate hosts are invertebrates
(usually copepods)  and sometimes  small fish  also.
Rarely do these kill fish, but the larval stages may
cause  sexual castration and, in one instance, we have
studied mortalities  caused by  larvae in the heart.

   6. Acanthocephala — these are similar to cestodes.

   7. Leeches — these are oviparous,  and may live
off the fish  for long periods.  Heavy infestations will
kill  fish and they  are the  vectors of fish trypanos-
omes, Crypotobia, and perhaps others.
   Parasitic copepods — Their visible  egg sacs are
borne  by  females  on gills,  fins, or  body of fish.
Eggs  drop  off, hatch,  go through seve-al larval
stages, attach  to  gills of fish, mate,  aii^. females
move  to  the final  site  of  attachment.  The adults
may  produce  ugly  and sometimes  fatal  lesions.
Massive  infestation  with  the  larvae on  the  gills
may suffocate the fish.

                  PROPHYLAXIS

   When fish are obtained  for experiments, it  is not
wise to assume  that they are  not infected with para-
sites,   particularly ectoparasites.   Therefore,  it is
judicious to handle them as  if they were infected. The
best method is  to examine  them and to treat infected
fish with formalin or potassium permanganate before
putting them in clean facilities.  They should then be
kept in "quarantine" for 2 to 8 weeks.  Most ecto-
parasites  will have been eliminated by the chemical
treatment, but Ichthyophthirius,  and perhaps others,
may remain alive  under the epithelium of the  fish;
if so  they  will probably become  evident during the
"quarantine" period.   In some  cases it  may not be
feasible to treat the fish; in this  case "quarantine" is
even  more  important.   During this period serious
infection with internal parasites might also become
evident.   If certified parasite-free fish stocks could
be obtained, as Dr Snieszko has  indicated, this would
be much better  than using  the above method. In the
future   it is hoped that lab-reared, parasite-free
fish can be had.

      METHODS OF CHEMICAL  TREATMENT

   Dipping.   The fish are immersed in a dip  net in
the disinfectant for the required  length of time.  This
method is useful when infected  fish are transferred
to clean facilities, or to reduce the parasite population
on the  fish.

   Prolonged treatment.    The  required amount  of
chemical is added directly to the  aquarium, pond, etc.
and  allowed to  remain for  the prescribed  length of
time.   It is then drained and fresh water is added.
 * Bureau of Sport Fisheries and Wildlife, Eastern Fish Disease Laboratory, Leetown (P.O. Kearneysville), W. Va.

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284
                           THE CONTROL OF FISH DISEASES AND PARASITES
   Indefinite prolonged  treatment.  As above, but the
pond, etc., is  not drained; the disinfectant is allowed
to dissipate.

   Concentrations and  dosages.     Hardness, tem-
perature,  pH,  organic  matter, and probably other
factors  influence  disinfectants; therefore, each in-
stallation  should test the suggested concentration on a
few fish before treating the entire  stock.

         TREATMENT AND PREVENTION

1. Fungi
   Ichthyosporidium - avoid  feeding raw sea  fish.
   Dermocystidium - treatment unknown.
   Saprolegnia and related fungi  - malachite green,
   1:15,000  dip for 10  to  30 seconds;  0.3  ppm for
   prolonged treatment  of  1 hour;  0.1 ppm for in-
   definite prolonged treatment.
2. Protozoa
   External protozoa  - treatment  listed in order of
   choice: (1)  formalin,  1:4000 to 1:5000 for 1 hour
   at 32°  to 60°F;  1:6000 for  1 hour at 60° to 85°F;
   15 to 25  ppm  for indefinite prolonged treatment;
   (2) potassium  permanganate, 1:1000 for 30 to 40
   seconds;  10  ppm  for 5 to 30  minutes; 2 ppm
   indefinite  prolonged  treatment  in ponds, but  1
   ppm in relatively clean aquaria;  (S)pyridylmercuric
   acetate (PMA), 2 ppm for 1 hour (toxic to rainbow
   and cutthroat  trout);  (4) acetic acid, 1:500 for 1
   to 2  minutes;  (5) sodium chloride, 1 to 3 percent
   for several minutes to 1 hour.

   One treatment usually suffices to break an epizootic
except for Ichthyophthirius disease, which ordinarily
must be treated  on alternate days  until  there  is no
longer any sign of "Ich".   This may take 5 weeks at
40°  to  54°F,   and  11  to  13 days  at 60° to  70°F.
Daily changing of  the  water or  a  rapid  continuous
flow  will  reduce  or  eliminate many ectoparasites
including "Ich".

   Most ectoparasites  have optimum temperatures,
which are similar  to those of the host, but there are
at least two genera of parasites that may be controlled
by changing the temperature of the  aquarium.   The
optimum temperature for Chilondonellais4Q°to5Q°'F.
This parasite is usually of no consequence in environ-
ments of  60°F or higher.  The  optimum for "Ich*
is about 60° to 75 °F;  there is seldom trouble from
"Ich" at 50°F or lower, and 90°F will kill the tomites.
The  latter temperature can  be used to control "Ich"
on tropical fish.

   Intestinal protozoa

   Hexamita — may be controlled with carbarsone or
calomel mixed with food at  0.2  percent for 5 days.
Yasutake  et al (1961) found  2-amino-5 nitrothiaxole
and  p.  carbamidophenyl  arsenoxide  to be more
effective.  Uzmann(1961) found one "strain" oiHexamita
to be nonpathogenic.

3. Trematoda

   Monogenea  (Gyrodactylus, Dactylogyrus, etc.) — use
methods for external protozoa listed above.
  Digenea (intestinal) — di-n-butyl tin oxide has been
used  at  0.3  percent of the weight of food (Allison,
1957).


   Digenea (metacercariae and adults in tissues) —
no treatment known.  Cercariae can kill fish if num-
erous.  Control of snail host is sometimes possible.
CuSO4 at approximately 3 pounds per 1000 sq ft (cf.
Mackenthun, 1958, for concentrations,etc.), and sodium
pentachlorphenate at 5 ppm have been used to control
snails;  the  latter will kill fish, but the  chemical
dissipates in 3 days.  Control of the bird or mammal
final host is sometimes possible.

   Molluscicides are being intensively investigated
by schistosome workers.

4. Cestodes

   Intestinal  forms — di-n-butyl tin oxide added at
0.3 percent of  the food weight for  1 day will remove
cestodes.  Kamala at 1.5 to 2 percent of the food for
1  to  2 weeks,  or by  oral capsule at 0.2 gram per
kilogram per  day has  also been used.  There is no
known control of the intermediate  hosts of cestodes.

   Plerocercoids in viscera and muscle — ro known
treatment.   Some success has been achieved in con-
trolling  Triaenophorus  by reducing the population of
the final host, Esox lucius.

5. Nematoda

   Intestinal forms have been removed from sturgeon
with Santonin at 40 milligrams per fish.

6. Acanthocephala

   There is  no  known  treatment for acanthocephala
of fish.   Possibly  the isolation of fish and control
of intermediate hosts would be helpful.

7. Hirudinea

   Leeches may be removed with the wettable powder
of  the   gamma   isomer  of benzene   hexachloride
(lindane, Gammexane) at 0.1 to 0.5 ppm. The solvent
of the  nonwettable   type  may be  toxic to fish; use
cautiously.   Sodium  chloride  at 1 to  3 percent for
up  to 1  hour may kill  some leeches.  Schaperclaus
(1954) recommends  quick  lime  at  0.5  gram  per
liter for 5 seconds.

8. Parasitic copepods

   Benzene  hexachloride and  salt may  be used as
above.   Ethyl  parathion  at 0.06  to 0.13 ppm has
been used by Osborn (1961).  Potassium permanganate
at 2 ppm for indefinite,  prolonged treatment kill some.
Adult  Lernaea  are  difficult to  kill,  but the larval
stages are vulnerable to formalin, etc.

9. Beetle larvae predators
   Kerosene  or vegetable  oil at 1.5 gallon per acre
are recommended.

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                                      The Control of Fish Parasites
                                                                                                      285
                                             REFERENCES
   The information given in this report is based on
many publications, most of which are listed in Hoffman
(1959) and  Snieszko, Hoffman,  and Wolf (in press),
but the  reader is referred to the  following selected
publications:

Allison, R.  1957.  A preliminary note on the use of
di-n-butyl tin oxide  to  remove tapeworms from fish.
Progr. Fish-Cult. 19: 128-130, and  19: 192.

Amlacher,   E.  1961.  Taschenbuch der  Fischkrank-
heiten.   Gustov Fisher Verlag, Jena. XI and 286 p.

Axelrod, H.R., and L.P. Schultz. 1955.  Handbook of
tropical  aquarium fishes.   McGraw-Hill  Book Co.,
Inc. New York. 718 p.

Bauer O. N.  1959.   Parasites of fresh-water fish
and  biological  principles  of their  control.   State
Sci.   Inst.   Pond  and  River   Fishery,  Leningrad.
(English transl. by  Israel Program Sci. Transl.
No. 622), 225 p.


Braker, W.P. 1961.  Controlling  salt-water parasites.
Aquarium 30:  12-15.

Cotton,  H.  W.  1952.   Specific  diseases of tropical
fishes.  Aquarium J.  23: 8-11.

Davis, H.  S.  1953.   Culture and  diseases of game
fishes.  Univ.  of California Press, 332 p.


Dempster,  R.  P. 1955.   The  use  of copper sulfate
as  a cure  for  fish diseases  caused by  par as. .tic
dinoflagellates of the  genus Oodinium.   Zoologica
40: 133-137.

Dogiel, V. A., G. K. Petrushevski, andYuI. Polyanski
(editors) 1958.  Parasitology of  Fishes (Transl. from
Russian by  Z. Kabata,  1961, Oliver and Boyd, Edin-
Burgh) 384 p.

Hoffman,  G.L.  1959.   Recommended treatment for
fish parasite  diseases.  Fishery Leaflet 486. USFWS
4 p.
Hoffman, G.L. 1962.  Whirling disease (Myxosporidia:
Myxosoma) of trout.   Fishery Leaflet  508.  USFWS
2 P.
Hoffman, G.  L.  1962.  A guide to the freshwater fish
parasites of North America (in progress).

Hoffman, G.L., and C.J. Sindermann. 1962.  Common
parasites of fishes.  (In press,  USFWS).

Mackenthun,  K.M.  1958.    The chemical  control of
aquatic  nuisances.   Publ.  by  Comm. on Water Pol-
lution, Madison Wisconsin.
Osborn,  P.  1961.   Pers.  comm.  Ozark Fisheries,
Stoutland, Missouri.

Plehn, M.  1924.  Prakticum  der  Fischkrankheiten.
Stuttgart. 179 p.   (English translation  as  Manual of
Fish Diseases).   (Project  No. 50-11861, 1939-1940,
Stanford University  and California State Div. of Fish
and Game. Typescript).

Schaperclaus, W. 1954.  Fischkrankheiten.  3rd ed.
Akademie-Verlag, Berlin. 708 p.
Snieszko, S.F., G.L. Hoffman  and  K.Wolf. (in press)
chapter  65, Fishes, in Diseases of Laboratory Animals
(ed. R.J. Flynn), Iowa State University Press.

Symposium.  Research of  fish diseases: a review of
progress  during  the  past 10 years.  1954.    Nine
chapters by 12  authors.   Trans.  Am.  Fish. Soc.
83: 217-349.

Uzmann, J. 1961.  Pers. comm., Western Fish Disease
Laboratory,  USFWS, Sand Point Naval Air Station,
Seattle,  Washington.

VanDuijn, C. Jr. 1956.  Diseases  of fishes. Dorset
House, London, England. 174 p.
Wolf,  K.  1958.    Fungus   or  Saprolegnia infestation
of incubating fish eggs. Fishery Leaflet 460. USFWS
4 P.

Yasutake,  W.T.,  DUR. Buhler,  and  W.E.  Shanks.
1961.     Chemotherapy of  hexamitiasis in  fish.  J.
Parasitol. 47:81-86.

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286
                           THE CONTROL OF FISH DISEASES AND PARASITES
                                              DISCUSSION
                  Chairmen: Dr. S.F. Snieszko and Dr. Glenn L. Hoffman, Bureau of Sport
                             Fisheries and Wildlife, Kearneysville, W. Va.
   The  first  topic  of discussion was the control
of the  copepod parasite, Lernaea.  The question was
asked  whether  Lernaea  could  be  controlled  in  a
2-acre  lake.    Dr.  Hoffman doubted that it could
be  done.   However, Bender (U.S.P.H.S., Cincinnati)
stated  the  control of the parasite has been accomp-
lished  in golden shiners using benzene hexachloride
at 0.1 ppm  in treatments spaced  3 or 4  weeks apart.
It was mentioned  that Schaperclaus   in  his  1954
book  entitled,  "Fischkrankheiten,"  described  the
use  of DDT at  1 to 50,000,000 for their control.
It was  stated that  formalin had  been used to kill
larval  copepods.   The possible  use of parathion and
malathion was mentioned.

   The  subject  of  snail  control  was introduced.
Snails   constitute  the intermediate  hosts  of  many
fish parasites.   The rapid flooding of an area with
rainwater  containing  0 to 6-7 ppm  of dissolved
oxygen  was  mentioned.    The  use  of  shellcracker
sunfish as a means of controlling snails was described.
Experiments are  under way in Puerto Rico using
shellcracker  sunfish to control snails  of the genus
Austrolorbis that carry the intermediate stages of
human blood flukes.  Shellcrackers were described
as being voracious snail eaters.

   There followed  a discussion of the holding of marine
fish in  ponds of a size up to 150 m  in  length.   The
case of whirling  disease  in mullet was described.
Whirling disease  in trout  and pond fishes  has  been
attributed to dietary deficiency  and eye flukes and to
myxosporidian  infection  of  the auditory   capsule.

   In the  discussion  of  columnar is  disease,  the
question arose whether  anyone  had ever  controlled
it in a pond or larger body of water.  Dr. Snieszko
reported an instance at Leetown in which  1 ppm of
copper  sulphate was  added to  a  smallmouth  bass
nursery pond in which  the disease was arrested.
Surber had made this treatment and he reported another
instance in which  a 0.5 ppm  treatment  of copper
sulphate arrested  Columnar is  in a pond near  Cin-
cinnati, where adult bluegills were being held in  live-
boxes.

   The  subject  of  leech  control  was  brought up.
Dr Hoffman stated that leeches  had been  controlled
with benzene hexachloride  but he did not know how
much had been used.  The control of tadpoles in fish
ponds was  discussed but no one knew of any method
that would  control them and at the same time permit
survival of the fish.   Dr.  Snieszko reported that
columnaris  disease had been found in tadpoles and
that their  presence  in the  wild might have led to
some of the heavy fish kills now being reported. He
told of the presence of columnaris in cold water fishes
in streams of the west coast where the disease had
been reported in water with a temperature of  10°C
or less.  Sulfonamides and terramycin could be used
for the control of the disease.   The occurrence of
columnaris disease in the Columbia River was partly
attributed to a series of impoundments created on the
Columbia River  that  increased water temperatures.
Increases in  the acidity of the water also decreases
the resistance  of  the  migrating  fishes.   Howard
Zeller of Georgia,  reported a serious columnaris
outbreak among golden shiners  and  bass in a 110-
acre  Georgia  lake.   Surber  reported a  selective
kill of  white  crappies by  columnaris  in  two  farm
ponds, one above the other, near Leesburg, Virginia.
Both of these ponds contained good populations of blue-
gill sunfish,  pumpkinseed sunfish, and largemouth
bass  that were unaffected by the disease that wiped
out the white crappies.  Mulligan reported instances
in which shad and carp died from columnaris disease
where bass and crappies were not affected.   Stresses
such as overpopulation, handling, and excessive tem-
perature are believed to be factors in the  outbreak
of the disease.
   Thomas (Alberta)  described  the increase  in the
number of Japanese  snails in Lake  Erie and in-
quired whether  it was an  intermediate host for any
fish parasites.   These snails  are being  killed by
acrolein used  for the  control of  algae and weeds
along the Lake  Erie  shore.   He  described how fish
were  driven away by  the presence of the herbicides.
Mr. Fisher (Missouri) inquired whether carp become
heavily parasitized. Dr. Hoffman replied that they were
sometimes known in Europe to be  quite heavily para-
sitized with monogenetic trematodes.

   Thomas reported that Triaenophorus  (tapeworm)
infestation of tullibees  could  be controlled in part
by  manipulation of the pike population that harbors
the adult worms.  Another parasite that causes fish
kills in tullibee populations  is an ergasilid parasite
Lernaea versicolor.   It is reported that this species
had a  seasonal  reproduction cycle  that lasted about
2 weeks in summer.

   Dr. Snieszko described how it  had taken  3 years
to rear furunculosis-free  rainbow trout at Leetown,
W.  Va.  There, he  stated, they have kept the unin-
fected fish side by  side with infected  fish  by strict
prophylactic measures and by using different utensils
for each tank.  Dr. Kranz of Pennsylvania, described
immunological  techniques used  to inject Aeromonas
in fish.  There they found that trout could be immunized
in  the  same  way  that  humans are immunized by
injecting mineral  oil  mixtures of  attenuated bacteria
numbering 4,000,000  to 5,000,000  cells per  cubic
Milliliter.  He reported the immunization of trout only 2
inches long.

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                                       The Control of Fish Parasites
                                                                                                       287
   Dr.  Snieszko called upon  his long time associate
and friend, visiting Cincinnati from Krabkow, Poland,
to  describe  their  methods  of  selecting fish for
maximum growth  and a  higher  level of health.  Dr.
Zarnecki  described  their fish-cultural  procedures
with carp  in  which  they  graded young carp  after
they had  been  in  ponds for 4  weeks.   The young
carp were graded into three groups and the medium
and  large-size fishes  were marked  by removing
pelvic fins and  placed in  ponds where they grew much
more rapidly than  the smaller-size fish. The selection
produced  a  14 to  18 percent increased growth rate
as well as healthier fish.

   Dr.  Snieszko reported that Dr. Schaperclaus ob-
tained  furunculosis-resistant trout by exposing trout
to  the  disease while they  were still  very young.

   Hepatoma disease was reported  to affect most of
those fish growing  at a very rapid rate  and eating
voraciously.    In  this  disease,  cancerous  growths
develop in the liver of fish as a result of eating certain
components  of  a dry meal diet.  A cooperative effort
is now  being  made  to  determine  which  of  the dry
meal diet components is  responsible.

   A  discussion of prophylactic  measures  against
furunculosis  then followed.   Mr.  Papier of Ohio,
asked whether  PMA deteriorated with time.   The
answer  to this was  "no-".  Furacin is now being used
as a prophylactic agent for the control of furunculosis.
It is very  stable, but  when  added to liver, breaks
down in a few hours.  Mr.  Papier inquired whether
any antibiotics had been used in ponds for parasite
or  disease control.  The answer to  this was in the
negative.

   Durrel, as long ago as 1928, found a bacteriophage
for Aeromonas  salmonicida to be  more prevalent in
ponds  where furunculosis  occurred.   Joe  Hahn,
Michigan State,  stated  that no spore formers had yet
been described  among  the bacterial diseases of fish.

   Dr. William  Beckman of the  World Food Organi-
zation,  stated that a world list  of specialists in fish
diseases has 3,500 names.

   Dr. Snieszko reported the availability of a series
of fish disease leaflets  put out by the Bureau of Sport
Fisheries and Wildlife.   Each leaflet treats a separate
disease  and contains the basic  information  on the
disease  and its control.  These can be obtained by
writing to the Department of the Interior,  Bureau of
Sport Fisheries  and Wildlife, Division of Information.

   Inquiry was made regarding availability of text-
books on fish anatomy.  The inquirer was referred to
Schaperclaus1 "Fischkrankheiten,"  which was  pub-
lished in 1954 but is now out of print, and to Ambecher's
Teichenbuch der Fischkrankheiten, 1962.

-------
                        DETERMINATION OF THE CAUSE OF FISH KILLS

                                         G. E. Bur dick, Chairman*

                  SOME PROBLEMS IN THE DETERMINATION OF THE CAUSE OF FISH  KILLS t

                                               G. E. Burdick
   In the  past  20 years the relationship of other
chemicals  and  conditions  to the toxicity  of pure
compounds has been studied rather intensively. These
contributions are  important  but not too helpful  in
finding  who,  or what, killed the  fish.  In fact, it is
almost  impossible  to  establish the  cause of a  fish
kill  if a positive identification and determination  of
the conditions,  chemicals, or complexes contributing
to death are required.
   Suppose  a small,  nontoxic  quantity of copper  is
added to  water.  A  downstream industry  adds a
concentration of zinc that  would be  nontoxic  in the
absence of copper. The stream water is soft, naturally
acid, and temporarily  has its oxygen content reduced
in passage through a  lake supporting a heavy algal
bloom.   All  factors contribute to a kill at a smaller
concentration than would otherwise be possible.  If
a fish kill occurs below the second plant, what caused
the  kill  and  who  is  responsible?   Must  we indict
Mother Nature  a?  well as both industries, since all
have changed the composition contributing to the kill?
Or,  if no kill would  have occurred if the oxygen had
not been reduced,  does this confer immunity to the
industries? How much time must be spent to evaluate
the possible effect of other components in the wastes
and  water?   This may  sound ridiculous, but can a
satisfactory conclusion be  developed on  the basis
of a  less thorough investigation?

   There  seems to be  a need to consider a different
approach in which absolute values shall be established
for  such  factors as  oxygen and  pH.  In the absence
of toxic compounds in  a quantity that  will cause a
kill without standards violation, a kill occur ring during
such a violation shall  be  ascribed to pH or oxygen.

   The addition of any chemical or waste that can be
shown to  change a previously nontoxic complex to a
toxic one  shall  be considered to cause the kill, even
though substances in  the  water act   to   increase
the  toxicity greatly.   This approach now forms the
basis for  the use of bioassays  to establish the source
of a  kill when additional supplementary evidence  is
not  obtained.    The  stream itself is a large-scale
bioassay,  but the location of  a kill is  only circum-
stantial evidence, since contributions from unknown
sources are always possible.
   Where this approach is justified legally, the use of
bioassays  to substantiate  the findings would more
nearly  equalize  the work load  of  the chemist and
biologist.
   Most fish  kills  are  the result  of a  spill, or
abnormal  discharge,  that exceeds  the  concentration
tolerated by  the  species present for a  short time.
This is short-term or acute toxicity. Chronic toxicity
may distribute the mortality over such a long period
of time  that no kill is noticeable.  The 24-,  48-, and
96-hour TLm'sare unsatisfactory for use with most
fish kills,  and a  time-concentration toxicity curve
based  on much shorter intervals should be  used. In
our laboratories we  have used the  logarithmic mean
of time at each  concentration  for  the  construction
of such curves.  This  reduces the effect of the in-
clusion of an abnormal fish by a factor equivalent to
the number of fish tested at that  concentration.  It
may  be  necessary  to  construct additional curves
covering the effect of other variables, such as oxygen,
pH, alkalinity, or hardness of the water, and the effect
of other  chemicals  that may  be present.  Slope
and curvature may vary in the  same species during
different periods  of the year and with the  previous
history of the water.
   The  discharge  causing a  kill may  be of short
duration.   Initially diluted in mixing with the stream,
it  will be further diluted from the front and back in
passage  downstream.   Depending upon  the  duration
of  discharge,  the  central portion will  retain  the
concentration of initial dilution for varying periods
of time.   The toxic agent and the source cannot be
ppsitively  identified unless stream samples can be
shown to be  lethal.   Early  observation of the kill
and  speedy  collection of samples is  necessary  for
any  evaluation.   In New York we  try  to solve this
problem by  requesting the public to call the local
game protector  as soon as a fish kill  is observed.
He investigates, collects samples, notifies the pollution
laboratory,   and obtains  any  further instructions.
   Fish kills may be grouped in two major categories,
those caused by oxygen deficiency and those due to
toxic compounds.
 *New York State Conservation Department, Albany, New York.
 1" Because of the large number of references involved, no attempt has been made to list authors publishing on various phases of the problem of
  interaction among various chemicals.   Those interested in additional references are referred to the reviews of the literature by the Water
  Pollution Control Federation Research Committee published in the Journal of that Federation and the former publications of this same
  organization.
                                                     289

-------
290
DETERMINATION OF THE CAUSE OF FISH KILLS
     KILLS CAUSED BY OXYGEN DEFICIENCY
   Fish kills that are brought about by oxygen defi-
ciency are  usually  the most  plentiful and,  in the
absence of toxic substances, the most easily solved.
The  character  of the district above  the point of kill
often excludes the chance of toxic substances,  from
other than the  suspected  source being present.  The
nature of the  operation  at the source may  further
support the absence of toxicants.

   Graphs  depicting  the  mean  lethal oxygen  con-
centration for  one of the  species involved in the kill
are  of  great  value  in establishing  the cause  to be
oxygen deficiency. A closed-jar procedure in which
the  respiration of the fish reduces the  oxygen to
lethal  or  near  lethal concentration  is adequate for
the establishment of  these curves.   Observation has
confirmed that there is close correlation between the
laboratory data  and  field conditions  producing the
same effect.  A  series of concentration-temperature
curves  for  some of the species frequently involved
in kills  in  New  York State  (Burdick et al.,  1954,
1957) is presented  in Figure  1.    For the sake of
clarity, the range of variation shown in the original
papers is not presented here, although it may be of
significance in partial kills.   Two curves  are pre-
sented  for  rainbow  trout  that  show small, but
consistently increased resistance of wild fish over
hatchery stock.   This may be due  to physiological
differences.    A  similar comparison of lake- and
stream-reared smallmouth bass indicates a higher
resistance of  the lake fish  to  reduced oxygen.  If
possible,  use  of spawning fish should be avoided
in such  experimentation  since the oxygen require-
    oJ I  1 I I I  I I I I I  I I I I  I I I I  I I I I  I I I I 1 I I I .1 I I I .
           50           «0           TO           80
                    TEMPERATURE, °F
   Figure 1. Mean lethal oxygen levels with closed-jar method.
                           ments of some species are higher and the fish exhibit
                           extreme variability.


                              The recommendations  of Doudoroff et al.  (1951)
                           for acclimatization to temperature and water, feeding
                           schedule, and other requirements for a validbioassay
                           should be followed unless it can be  shown that failure
                           to do so will introduce no error.   Exception can be
                           made in  the volume of experimental solution.  It has
                           been found  in  our  laboratories that no significant
                           difference  occurs  in reaching the  endpoint  in 2 to
                           2-1/2  hours  compared  with more than 6 hours.


                              If no such data are available for any species found
                           in the  kill or  if confirmation of these  curves is
                           desired,  additional  data  should  be obtained.  While
                           fish  and water can be transported to the base labora-
                           tory,  modification to  a field method can save time
                           and effort. Such a field method to provide the needed
                           comparisons is  tentatively suggested here.   This is
                           based  on theory  and  has not  been field tested.  It
                           should also evaluate the interaction of those chemicals
                           showing  increased toxicity  with  reduced oxygen.


                           PROCEDURE  FOR FIELD  ASSAY  OF LETHAL
                                      OXYGEN CONCENTRATIONS


                              Water is brought from points where  the  stream
                           is in natural condition to just above the entrance of
                           the suspected waste.  The containers  should be set
                           in the water and brought to the same temperature.
                           If upstream  discharges  are  present or suspected,
                           water from this  location should also be  used.  Jars
                           similar to those described by Burdick et al.  (1954)
                           are convenient.  The size should permit the endpoint
                           to be reached in not less than  2 and preferably 4 to
                           6  hours.   Experimental  fish can be taken from the
                           stream,  with care to handle  and excite them as
                           little  as possible.  The  stream  can  be  used as a
                           temperature  bath,  recording temperatures at 1/2-
                           hour intervals.    If the  temperature fluctuation is
                           extreme,  all jars  should be started within a  short
                           time period.   From  5 to 10 jars from each water
                           should be enough to  determine  the  endpoint.   A
                           single fish should be used in each jar.

                           INTERPRETATION OF RESULTS


                              Any significant  quantity of toxic material  acting
                           synergistically with low oxygen should produce a higher
                           oxygen at endpoint because of the  decreased respi-
                           ration  time.   This can  be tested statistically and,
                           if significant,  confirm the presence  of a toxic  com-
                           pound.    Toxicity  from  an upstream source can be
                           ignored if the differences  are slight.

                              If the  oxygen was less at the point of kill than the
                           requirement of the species at that  temperature, the
                           suspected source is the probable  cause. If the oxygen
                           was  higher, the  sample either  does not  correspond
                           with  the  conditions at  the  time of the kill or the
                           effluent  also  contains  toxicants.    A modification
                           using dilution  with upstream water could decide this
                           point.

-------
                        Some Problems in the Determination of the Cause of Fish Kills
                                                291
      KILLS CAUSED BY TOXIC COMPOUNDS

   Industrial  wastes  and  agricultural  and pesticide
chemicals are the main causes of this type  of kill.
After collection  of a  sample assumed  to contain the
toxic substance  or complexes causing the kill, the
sample must be  proven toxic.   This can be done by
routine bioassay  in the majority of cases.

   A chemical determination of the toxicant requires
information on the process chemicals,  products, and
by-products  involved in industrial  manufacture,  or
the chemical in  use,  the amount,  and area in which
it is used with the agricultural and pesticide chemicals.
A decision must then be  made on the chemical or
chemicals to be determined.   For  many  chemicals
satisfactorily sensitive methods may not be available
at the  toxic  or   sublethal  level.   Proper methods
for  concentration  may also be  lacking.  One of the
greatest needs in the  pollution field is for more sen-
sitive procedures for determining many chemicals.

   It is an obvious impossibility to test any effluent
for  all possible  chemicals  that  might  enter into
interaction in the toxicity.   Such a  procedure would
have no  place in field operations  in  pollution.   It
is believed  that  no  mathematical models have yet
been proposed to cover interaction of systems of
even two to three chemicals, with variations of oxygen,
pH,  and  other   factors,  that  would enable it to be
applied to field  situations.    Even  if  such a model
were available,  other chemicals  would have to  be
excluded before it could be applied.

   Where  a  method  is available to test for  a toxic
chemical, and  the concentration  is found to  exceed
the  lethal level  for the pure  compound, interaction
with  other chemicals cannot yet be excluded.  Re-
sponsibility can  be fixed by bioassay if an equivalent
concentration of  the  pure  compound  fails to show
an increased or  decreased death time in comparison
with the stream samples.

   If the  death times  are different, the  source of the
interaction might be  determined  by the closed-jar
assay as  suggested  under  kills  from oxygen de-
ficiency.  Further work is unnecessary when the source
can be confined to a single effluent.

   The wording of the law  would decide any further
action to  be  taken   if the  complex is found to be
derived from multiple sources.

THE  USE OF POST  MORTEM  ANALYSES IN THE
DETERMINATION OF THE CAUSE  OF  FISH KILLS

   Post mortem  analysis to determine  the  cause of
death  in  man has been so  widely publicized that
probably every biologist has dreamed of using a similar
procedure to determine the cause of death in fish.
Possibilities are indicated in the reported work of
Carpenter (1927) in   revovery  of heavy metals  by
acid stripping  of fish. DDT  can be recovered from
the stomach contents of fish allegedly killed from eating
floating insects  carrying DDT.  Cyanide is so fre-
quently determined  in  man  that it  is natural  to
seek a similar procedure for fish.
   One  of  our laboratories  spent  over 6 months  in
preliminary  work on such a procedure several years
ago.   Much  of  the  work  was  chemical  in nature.
Both  fish tissue and the gall bladder contents gave
indications of heavy  cyanide content  by the Aldridge
method (Aldridge,  1945).  Baffles were  indicated to
avoid possible entrainment  in the distillate when an
acid distillation procedure was involved.

   At relatively large concentration the cyanide con-
tent varied directly with the exposure concentration.
The recoverable cyanide fell over a  24-hour period
if the fish were allowed to stand in fresh water.  This
was particularly true with the use of the gills. The
data are presented in Figure 2.   The decrease was
                68   10   12  14
                  HOURS IN WATER
                                         tO  22  24
Figure 2. Loss of CN  in water os shown by recovery from gills
        of fish killed in: solutions containing (a) 2.8 to 3.0 and
        (b) 0.60 to 0.62 ppm as CN~.
somewhat less noticeable with the combined tissues
of heart, liver,  and  spleen presented in Figure 3.
                6   •   10  12   14

                  HOURS IN WATER
                                  16   18  20  22  24
Figure 3. Loss of CN  in water as shown by recovery from heart,
        liver, and spleen offish killed in: solutions containing
        (a) 2.8 to 3.0 and (b) 0.60 to 0.62 ppm as CN~.

   The use  of liver and spleen (Figure 4) appeared to
restrict  the  variation  to   the  range of individual
variation of the material.
1.4
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 Figure 4. Loss of CN  in woter as shown by recovery from liver
     »   and  spleen of  fish killed in solution  containing 0.67
         ppm  as CN .

-------
292
DETERMINATION OF THE CAUSE OF FISH KILLS
   The  cyanide found in unexposed  fish was  highly
variable.   At  the  higher levels it occasionally ap-
proached that found as minimal levels in fish exposed
to cyanide.  Losses on standing in water raised prob-
lems in evaluation not easily solved. The studies of
Doudoroff  (1956) and Lipschuetz and Cooper  (1955)
on metal  cyanide complexes raise further questions
on  the validity  of  such  a determination.    These
papers indicate increased toxicity over that of KCN
for some metal complexes, reduced toxicity in others.
These relationships  are not completely explainable
on the basis of total cyanide, removal  of cyanide by
the  metal  complex,  or  the availability of HCN,  but
in some  cases must involve synergism of the metal.

   The work of Burdick et al. (1958) on the toxicity
of cyanide  to  brown  trout and  smallmouth bass at
two  oxygen levels indicates that reduction of oxygen
will  greatly increase the toxicity of cyanide.   The
curves  are presented in  Figure 5  for purposes of
comparison.  The curves are not  parallel and indicate
a greater effect in the intermediate  concentrations.
This raises an additional problem in the evaluation
of the quantity of cyanide producing death  based on
a post mortem analysis. It was concluded that there
would be such a limited usefulness for such a method
that  the work has been abandoned.

   With the great number of possible  contaminants to
be found  in water  that can enter into  interaction to
produce death, the use of any post mortem procedure
for the accurate determination of the cause of death
of fishes seems theoretically impossible.

   Man's environment is much more stabilized and loss
or the further  intake of toxic substances by ingestion
or  respiration is  less  likely  than in the  lower
iooo
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BROWN TROU
SM ALLMOUT








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                                               ppm AS CN~


                             Figure 5. Effect of oxygen on the foxicity of cyanide.
                                     Brown Trout:  Oxygen ppm - (o) 9.7  (b) 5.1 to 5.3
                                     Smallmouth:  Oxygen ppm - (a) 9.0  (b) 4.1 to 4.2
                           vertebrates  where  circulation often continues for
                           some time after  death.  In fish, the intake of most
                           toxic materials is through the gills, a semipermeable
                           membrane through which exchange may occur from
                           one liquid medium to another quite readily .The problem
                           in fish is thus much more complex and less readily
                           solved than in the case of man.
                                              REFERENCES
Aldridge, W.N.: 1945, The estimate of micro quantities
of  cyanide and thiocyanate,  Analyst 70: 474-475.
Burdick, G.E., Lipschuetz, M., Dean, H.J., and Harris,
E.J.: 1954, Lethal  oxygen  concentration for  trout
and  smallmouth bass, N.Y.  Fish  &  Game Journal
1(1): 85-97.
Burdick,  G.E.,  Dean, H.J.,  and Harris, E.J.:  1957,
Lethal oxygen concentrations for yellow perch, N.Y.
Fish & Game Journal 4(1): 92-101.

Burdick,  G.E.,  Dean, H.J.,  and Harris, E.J.:  1958,
Toxicity of cyanide to brown trout and smallmouth
bass,  N.Y. Fish  &  Game Journal  5(2): 133-163.

Carpenter,  K.E.:  1927, The lethal  action of  soluble
metallic salts on  fishes,  Br. Jour. Expt. Biol. 4(4):
378-390.
                           Doudoroff, P.,Anderson,E.G.,Burdick, G.E.,Galtsoff,
                           P.S., Hart, W.B., Patrick,  R., Strong, E.R., Surber
                           E.W.,  and VanHorn,  W.M.: 1951, Bio-assay methods
                           for  the  evaluation of acute  toxicity  of industrial
                           wastes  to  fish.   Sewage  and Ind. Wastes 23 (11):
                           1380-1397.
                           Doudoroff, P: 1956, Some experiments on the toxicity
                           of complex cyanides  to fish, Sewage and Ind. Wastes
                           28(8): 1020-1040.
                           Lipschuetz, M., and Copper, A.L.: 1955, Comparative
                           toxicities of potassium cyanide and potassium cupro-
                           cyanide to the western black-nosed dace, N.Y. Fish
                           & Game Journal 2(2): 194-204.

-------
             An Experimental Analysis of the Factors Responsible for Periodic Fish Mortalities
                                              293
     AN EXPERIMENTAL ANALYSIS OF THE FACTORS RESPONSIBLE FOR PERIODIC FISH MORTALITIES

               DURING WINTER IN BUSHVELD DAMS IN THE TRANSVAAL, SOUTH AFRICA

                              B. R. Allanson, M. H. Ernst, and R.  G. Noble*
                 INTRODUCTION

   The  highveld-bushveld  transition region in the
Transvaal, South Africa, lies at an altitude of be-
tween 3,800 and 4,500 feet above sea level,  and the
dry  winter season  is accompanied by frosts and
extended cold  periods.  Allanson and Gieskes (1961)
have reported some of the limnological changes brought
about by these cold winters in Hartbeespoort Dam, 18
miles west of Pretoria.   They have reported water
temperatures of 13°C during July and August, months
when  water temperatures are always lowest.  It is
usually  during  these months  that  extensive  fish
mortalities, particularly  of   Tilapia  mossambica
Peters,   an introduced  cichlid,  are reported.  In
recent years considerable speculation about the cause
has been made;  the discharge of toxic effluents from
factories  and  local  authorities in  the catchment of
these dams has  often been  blamed.  Sport  fisher-
men have put forward another viewpoint and suggested
that temperature might be an important factor that
should be  studied in  some detail.  To  this end the
National Institute for Water Research cooperated with
the biologists  of the Department of Nature Conser-
vation, and an attempt was made at an experimental
level to understand the effect of low temperature upon
T. mossambica in an endeavor  to decide whether or
not to support this view.

   The following experiments were carried out after
sighting studies:
1.  The effect  of low  temperature  on the behavior
   of fish on direct  transfer  into waters of low and
   high total dissolved solid   (TDS) content  during
   a set exposure time.
2.  The estimation of an  "effective concentration 50"
   (EC50) using percentage collapse as the dependent
   variable.   This  study  was done only in water of
   high TDS.
3.  The  estimation  of a  "lethal concentration 50"
   (LC50) using percentage mortality as the dependent
   variable in water of low and high TDS.

   This  study  has formed a second part of a larger
study on the effect of temperature upon T. mossambica.
The first part dealing with the tolerance and resistance
of  this species of fish to high temperature is awaiting
publication.

                    METHODS

   The  Lowveld  Fisheries  Research Laboratories
supplied 1,200  young T. mossambica, measuring be-
teen 10 and 12 cm in length.  The fish in the sample
supplied  were  between 6 and  8  months old and were
collected from open dams  in which the temperature
varied about 25°C.   This population was randomized
on arrival  in the laboratory among six holding tanks.
Water  was continuously supplied to the  tanks from a
borehole and, after  ion exchange to remove an excess
of iron in solution, had the following  composition:
  Table 1. THE COMPOSITION OF BOREHOLE
           WATER SUPPLY TO THE HOLDING
           TANKS AFTER ION EXCHANGE
  Conductivity, p. mhos
  PH
  Total dissolved solids as ppm
  Nitrate as ppm NOs
  Phosphate as ppm PO4
  Alkalinity bicarbonate as
  Sulphate as ppm 804
  Chloride as ppm Cl
  Total hardness as ppm CaCOs
  Ca hardness as ppm CaCOs
  Mg hardness as ppm CaCOs
  Sodium as ppm Na
  Potassium as ppm K
  Iron as ppm
22.5
 6.5
19.0
 0.20
 0.01
 8.2
 0.9
 0.8
 7.1
 4.9
 2.4
 0.6
 0.3
 0.2
   The pH was kept roughly constant between 6.9 and 7.0
by strong aeration  of the holding tank water, which
was kept at 20°C ± 0.1 °C.

   The fish were maintained under these conditions for
14 days before the investigation started.   The in-
vestigation lasted for 3 months;  thus, the last group
of fish  to be used had lived under these conditions
for 14 weeks.

   For  each  phase  of  the investigation  the  total
number  of fish in any one holding tank was randomized
between  10  buckets from  which  6 buckets  were
randomly taken.   As far as possible  20  fish were
used in  each of six experimental  or chill tanks, each
of which  had a capacity of 2 cubic feet.  The tem-
peratures in  the experimental  aquaria were kept
constant (± 0.1 °C) by modified "Techne Tempunits,"
and the water was fully saturated with oxygen  (7 ppm)
by aeration at approximately 2.5 liters/minute.

   Previous sighting experiments had shown clearly
that  it  was not  possible to treat the  investigation
on a time-mortality basis as  Brett (1952) had done
using salmon  fry, because no clear-cut indication of
death such  as gaping or permanent erection of the
* National Institute for Water Research and Department of Nature Conservation, Transvaal.

-------
294
DETERMINATION OF THE CAUSE OF FISH KILLS
pectoral fins was available in T. mossambica.  The
whole investigation,  therefore, rested on response to
"doses*  of  temperature  for  given exposure times.

   In  each  of  the three phases of the  study,  fish
held at the  temperature  conditions described above
were  acclimated  to 25°C for  2  days at an adjusted
pH of 7.0. Earlier unpublished studies on the tolerance
and resistance of T.  mossambica to high temperatures
have  shown that  this cichlid  species is capable of
very rapid acclimation to high temperatures.  From
these data it was known that 2 days' exposure to 25°C
from a holding temperature of 20°C was quite sufficient
to effect complete thermal  acclimation to the higher
temperature.  The technique of direct transfer to the
experimental temperatures was used.

THE PATTERN OF  RESPONSE ON DIRECT TRANS-
          FER TO LOW TEMPERATURE

   A  sighting experiment at the start of this study
indicated that the temperature  at which responses
to chilling  occurred might vary with the  total dis-
solved solid (TDS)  concentration  of the water used.
Thus,  in the  further  design of the investigation an
attempt  was made  to repeat experiments  in both
borehole water and tapwater supply, the latter having
                           a  TDS  concentration of  130  ppm, which  is at least
                           six times that of the former.
                           WATER  LOW  IN  DISSOLVED  SOLIDS - Borehole
                           supply, TDS 19 ppm.

                              In  Figure 1  the variation in pattern of collapse
                           is  clearly shown in relation to temperature and time.
                           The  behavioral   categories  of  normal  individuals
                           were:    (a) Active,  (b)  quiescent  and sporadically
                           active,  (c) quiescent, and  (d) moribund but upright.
                           The  categories  of  collapsed  individuals  were:  (a)
                           Lying on right or left side but with occasional sporadic
                           activity and (b) no recovery at all from lying on right
                           or left side.
                              Between 10.5° and 11.5°C there was clear evidence
                           of an initial high incidence of collapse, followed by
                           a gradual recovery  at 10.5° and 11.0°C.  Recovery
                           at 11.5°C  was  more  rapid and led to a higher in-
                           cidence of recovery by the individuals in the sample.
                           At all three  temperatures there  was  a  period of
                           maintained  recovery  lasting between  120 and  150
                           minutes.   This was followed by a variable rate of
                           collapse  that depended on temperature and was most
                           rapid at the lowest temperature, 10.5°C.
                                                                          xxx>ooaooix*_ _.	
                                                                                          10.5° C
                                                                                          11.0 C
         13.00
                     14.00
                                  1500
                  moo           i7.oo
                      TIME IN  HOURS
                                                                         18.00
                                                                                      1StOO
                                                                                                   2000
                    Figure 1. The Pattern of collapse for T Mossambica in water of low dissolved solids.

-------
             An Experimental Analysis of the Factors Responsible for Periodic Fish Mortalities
                                                                    295
   At  temperatures  above  11.5°C  the initial high
incidence of collapse was not found, although two
or  three individuals did collapse immediately upon
transfer. As Figure 1 shows, this number decreased
until at  13.0°C no initial collapse of  any  of the fish
used was observed.   Only after 180 minutes at these
temperatures did the incidence of collapse increase
with time.
   Because  there was in all cases either a recovery
from initial collapse  on transfer for the majority
of individuals used or a  slow increase in incidence
of collapse only after  180  minutes' exposure to the
temperature of the experimental aquaria, two com-
ponents  of  the  changes  brought  about by  cold  as
described by Pitkow  (1960) were considered evident.
There  was  a recovery  from the shock that occurred
between 10.5°andll.5°C.  This was followed eventually
by collapse  into secondary chill coma from which
there was no recovery on transfer  into warmer water.
There  was no evidence of primary  chill  coma since
recovery  occurred,  and  as  Pitkow  has pointed out,
a primary  requisite  of primary  chill coma is that
the  organism does not recover unless transferred to
warmer water.
                        A  further experiment designed primarily to obtain
                      an estimate  of temperature EC50  where six random
                      samples of 20 fish were exposed for 1,000 minutes to
                      temperatures from  13.0° to 15.5°C provided further
                      evidence that supported the existence of a secondary
                      chill  coma in T. mossambica.

                      WATER HIGH IN DISSOLVED  SOLIDS - Tap water
                      supply, TDS  130 ppm.

                        The data  available are given in Figure 2.  Unfor-
                      tunately these data are not as detailed  as obtained
                      under (1) above.  A similar trend is found in the re-
                      sponse of fish to immediate transfer into water  of
                      high  dissolved  solid content as is  found in the im-
                      mediate transfer into water of low TDS.

                        Lower temperatures and longer exposure time,
                      however, were necessary to obtain similar responses
                      in water high in dissolved solids.

                        In  addition,  the  data  given  in  Figure 2  indicate
                      the temperature at which  primary chill coma  #as
                      found and a possible gradation into a shock-recovery-
                      secondary  chill  coma  sequence.  At a temperature
                      of 11.5°C this sequence appeared to be  replaced by
                        15
30         45        60        75        90
      TIME IN MINUTES- MULTIPLY  BY 10
                                                                                  105
                                                                                            120
                    Figure 2. The pattern of collapse for T. Mossambi co in water of high dissolved solids.

-------
296
DETERMINATION OF THE CAUSE OF FISH KILLS
low incidence  of collapse due to shock and eventually
lead  to  a  complete recovery  of all the fish in the
sample used.

EFFECTIVE CONCENTRATION 50 USING PERCENT-
AGE  COLLAPSE AS THE DEPENDENT VARIABLE

   The preceding analysis of the pattern of response
on direct transfer to water of low temperature leads
logically into an investigation of the usefulness of col-
lapse as a metameter from  which an EC50 could be
estimated.   The estimation of an  EC50  was  also
supported by  field observations made in winter when
numerous juveniles of T. mossambica were found
lying  on the bottom of the shallows in the reservoirs
of this region.

   Because the waters of these irrigation reservoirs
had concentrations  of  TDS  nearer  to  the  tapwater
supply in the laboratory than to the water of the bore-
hole,  the estimation of an EC50 for this species was
made by using tapwater. The experimental  data are
given in  Table 2, which combines the data from three
random groups of fish.
                          LETHAL CONCENTRATION 50

                             The  pattern of mortality after 1,000 minutes and
                          the pattern as measured by the number of individuals
                          that  did not recover after transfer to water at 18°C
                          for 6 hours were  not found to  be homogeneous either
                          in tapwater or in borehole water. This was due mainly
                          to the small numbers (20 individuals) used at each
                          experimental temperature.   In  Figure 4,  however,
                          data from two random blocks of fish are  combined
                          and  suggest that a split probit of mortality may be
                          expected.    Thus,  mortality  from  shock  may be
                          separated  from  that  due  to primary  chill  coma
                          after 1,000 minutes' exposure.
                             The  shock  effect following  immediate  transfer
                          to cold temperatures is obviously of great importance
                          in the  design and interpretation of experiments and
                          results and is  one that Brett (1952) clearly indicated
                          in his time mortality studies on salmon fry.
                             From these data, however,  it  was not possible to
                          obtain  an  estimate  of  the LC50 in  tapwater  supply
                          and  it  is  doubtful at this  stage whether the LC50
                          has  any  tangible  ecological  significance.
               Table 2.  THE INCIDENCE OF COLLAPSE IN T. MOSSAMBICA IS EXPRESSED
                        AS A PERCENTAGE OF THE NUMBERS EXPOSED AT EACH OF THE
                        (FOLLOWING) TEMPERATURES INDICATED AND FOR THE TIME
                        GIVEN. THE FISH WERE ACCLIMATED FOR 2 DAYS IN TAPWATER
                        WITH TDS 130 ppm AT 25°C and pH of 7.0
Temp, °C
6 min.
30 min.
1,000 min.
8.0
100
100
100
8.5
65
90
100
9.0
55
85
95
9.5
55
50
65
10.0
55
55
45
10.5
35
15
20
11.0
30
16.2
5
11.5
15.8
26.3
0
12.0
5
5
0
12.5
25
0
0
13.0
0
0
0
13.5
0
0
0
   An empirical probit plot of the collapse data after
 1,000 minutes is given in Figure 3.  The fitted probit
 line was computed according to the method of Finney
 (1952)  and the experimental  data are regarded as
 homogeneous;  the graphical estimate of the EC50 is
 9.9°C, and that by calculation, 9.90°C.
                             It should be noted that, so far, it has been possible
                          to induce true  secondary chill coma and, therefore,
                          mortality in  tap water  only between 10°C and 11 °C.
                          Above this temperature and up to 15.5°C an exposure
                          of even 4,000 minutes did not cause any change in the
                          survival of the fish used.
                                                                   O	-O EMPIRICAL PROBIT
                                                                   •	«FITTED PROBIT
                        110-

                        11.5-

                        no-



                        1OO-



                        9.0-

                        8.5 -
                     ED 50=95°C
                                               PROBIT OF COLLAPSE
              Figure 3.  The empirical probit and fitted probit of collapse for T. Mossambica after 1,000 minutes'exposure.

-------
              An Experimental Analysis of the Factors Responsible for Periodic Fish Mortalities
                                               297
   11.0



    10.0



    9.0


a."
Ill  8.0
t-


    7.0



    6.0
                   <)0\<
                                            \
        2    5   10   20  30 40 50 60 70  80   90  95   98

                        MORTALITY
Figure 4. The mortality of 7". Mossamlbico at low temperatures in
        water high  in dissolved solids at pH 7  and after 2
        days'acclimation at 25.0°C.
A  POSSIBLE  EFFECT  OF THE  CONCENTRATION
OF TOTAL DISSOLVED SOLIDS UPON THE LC50

   Pitkow (1960), working onthe characteristics of cold
tolerance in the guppy, Lebistes reticulatus, reported
that increasing the osmotic pressure of the water used
had no significant effect upon the guppy's cold toler-
ance.   Throughout this investigation a borehole water
supply with TDS  of  19  ppm was  used  as far as
possible  in parallel with  tapwater that had a  TDS of
130 ppm.  As a result there appeared clear indications
that change in  the tonicity of the water supply certainly
had an effect  both upon the LC50 and EC50, although
it  was not  always easy to repeat the investigation
on remaining random groups after the  initial striking
difference  between mortality  was observed.  These
data are  given in Table 3.
   This  lack of  reproducibility might be  due to
variations in conditions during the holding of fish under
laboratory conditions for a  long  time.  This  was
necessitated  because this investigation  was carried
out during our winter period when no additional stocks
of fish  could be obtained from the Lowveld Fisheries
Research Station.   It  is  considered, however,  that
sufficient data are available for an effective experi-
mental design.

                   CONCLUSION

   Finally, the results obtained from this investigation
indicate quite clearly that low temperature is certainly
an important factor for fish mortality in the reservoirs
in the highveld-Bushveld transition. How the effective-
ness  of  this  factor  changes with changes in other
factors  such as dissolved oxygen, pH,  and low con-
centration  of  toxic  substances  obviously  requires
further study.

             ACKNOWLEDGEMENTS

   The  authors  wish to  express their  appreciation
of  the  kind  cooperation  of Dr.  G. L.  Lombard,
Officer  in  Charge,  Lowveld Fisheries  Research
Station.    This paper is published by permission of
the  South African Council for Scientific and Industrial
Research and the Directorate of the Transvaal  De-
partment of Nature Conservation.

                  REFERENCES

Allanson,  B.R., and Gieskes, J.M.T.M. (1961) - In-
vestigations  into  the Ecology of Polluted water in
the  Transvaal  Part I. Hydrobiologia  18  (1-2)  pp
1 -  93.

Brett, J.R. (1952) - Temperature Tolerance in Young
Pacific  Salmon  Genus  Oncorhyncus.   J. Fish. Res.
Bd. Can. 9 (6) pp 265 - 323.

Finney,   D.J.  (1952) -  Probit Analysis, Cambridge
1952.

Pitkow, R.B. (1960) - Cold Death in the Guppy. Biologi-
cal  Bulletin 119 (2) pp 231 - 245.
               Table 3.  THE POSSIBLE EFFECT OF CHANGE IN DISSOLVED SOLIDS CON-
                        CENTRATION ON THE MORTALITY OF T. MOSSAMBICA EXPRESSED
                        AS A PERCENTAGE AFTER 1,000 MINUTES' EXPOSURE AND AFTER
                        6 HOURS IN WARM-WATER RECOVERY TANKS AT 18°C.
Temp, °C 13.0
H2O with low
dissolved
substances
H2O with high
dissolved
substances

90

0

13.5

100

0

14.0

90

0

14.5

65

0

15.0

55

0

15.5

40

0


-------
298
DETERMINATION OF THE CAUSE OF FISH KILLS
                                              DISCUSSION
   Most of the investigators in pollution biology are
very interested in  good post  mortem methods that
will  give reliable answers as  to the cause of death.
Such  methods  would lessen the burden of proof on
the prosecution in  cases following fish kills. Fre-
quently bioassay techniques are not practical or cannot
be used to secure the necessary data. There has been
only limited  work up to the present on the develop-
ment of such autopsy techniques.  Many difficulties
have  been  encountered. These include difficulty in
analysis  of many of the offending  compounds, little
or  no knowledge  of   the mode of  action  of these
materials on aquatic  life,  and  pitfalls inherent in
the  organisms  themselves  such  as autolysis  and
back leaching.

   Methods that have been developed include a method
                           for cyanide, by the laboratory at Pitlochery, Scotland;
                           histological determinations on gill damage for several
                           of the heavy metals, and methods for the determination
                           of DDT in tissues.  All of these methods have certain
                           drawbacks  and have been useful only in selected cases.

                              Two remedies  were  proposed for this problem.
                           They were  better liaison with industry and all potential
                           polluters to give previous information on potential
                           pollutants,  i.e., bioassay before  the  fact, and a de-
                           termined effort to develop autopsy techniques along
                           the lines  of those used in human  medicine today.

                              The  session concluded with a  spirited discussion
                           of the  problems encountered in the rearing and har-
                           vesting of   Tilapia  sp.  in the United  States and in
                           temperate and equatorial Africa.

-------
                     THE ARTIFICIAL EUTROPHICATION OF OUR WATERS
                                       Eugene A.  Thomas, Chairman *

               THE EUTROPHICATION OF LAKES AND RIVERS, CAUSE AND PREVENTION
                                           Eugene A. Thomas
                 INTRODUCTION

   As  we all know, preserving the purity of rivers
and  lakes  in all  industrial  countries and wherever
many people live  close together has become one of
the  important tasks of men in recent decades, es-
pecially since the  end  of the Second  World  War.
In many countries,  it was recognized a century ago
that the pollution  of lakes and rivers should be pre-
vented  and, even at that time, laws and regulations
were made to preserve the purity of the water. In
Switzerland, for example,  on 10 December 1876, the
excellent law concerning public  hygiene  and food
inspectors  came  into force and on 1 June 1881 the
explicit Zurich  cantonal  regulation regarding the
preservation  of purity of water was issued.  When
this regulation was passed,  the director of the medical
department laid down conditions that had to be  met
for running water at 50 meters  from a sewage inlet
and  for standing water at 100 meters from such an
inlet.   These conditions referred to potassium per-
manganate consumption (less than 60 mg/liter), nitro-
gen  in  a soluble organic  compound (less than 1 mg/
liter),  soluble metal compounds  of lead, copper, etc.,
harmful to  health (less than 2 mg/liter),  arsenic in
any  form  (less than 0.05 mg/liter), active chlorine
becoming  free  on  acidulating with sulphuric  acid
(less than  1 mg/liter), hydrogen  sulphide or sulphide
decomposable with  carbonic  acid  (less than 1 mg/
liter),   free acid (in 1 liter less than is neutralized
by  10   ml  normal alkali),  free  alkali  (in  1  liter
less than   is neutralized by  10 ml  normal  acid),
and  so  little coloring substance that a 10-centimeter
layer  of water  in a white  container did not show any
definite  color  in  daylight.  All these  regulations,
however, were far too seldom enforced.

   Today there is greater understanding among re-
sponsible  authorities and  by many  people  of the
need for purifying sewage. In many cases, however,
it is not easy even for an expert to determine how
extensively  sewage must be purified before it may be
discharged into rivers or lakes. Biological problems
are  of especial  importance here.  After purification,
sewage  that is ready to be discharged may be absolutely
nonpoisonous  and largely freed of organic substances
and  yet it  can  produce phenomena that are unde-
sirable  in  many respects.   The  following exposition
deals with these phenomena  and  the possibilities of
preventing them.

   I  should  like to thank the American Department of
Health,  Education, and Welfare, especially Dr. Clar-
ence M. Tarzwell, Chief of Aquatic Biology, Research
* Limnologist, Zurich University and Cantonal Laboratory, Switzerland.
T Translation: Dr. M. V. Wynne, Zurich.
Branch,  Division  of  Water  Supply  and  Pollution
Control, for the invitation to attend this Third Seminar
on  Biological  Problems  in Water  Pollution.   I am
also  grateful to the American Society of Limnology
and Oceanography, the Chancellor of Zurich University,
and the  Board of Health  of the Canton of Zurich for
supporting the journey to America.

I.  The original state of lakes and rivers

   A. The  original  state of lakes

   Since the  beginnings of limnological research,
considerable interest has been shown in the morphology
of lakes.  In the "Handbuch der Seekunde" (Handbook
of  Information on  Lakes) by  F.A. Forel (1901), the
section on morphology comprises one-seventh of the
book.  Since then it has very often become necessary
to deal especially  with lake volume when interpreting
results of research on lakes. In northern Switzerland,
for example,  all lakes of 20 meters' depth  or more
with  at least  500,000  square meters of surface
area  belonged  to  oliogotrophic  types until a few
decades ago, as research  on the mud sections has
shown (Thomas, 1949).   Today most of these lakes
are  in  a  eutrophic state  as  a  result of artificial
fertilization.  For  the  following comments, lakes are
divided into two morphologically  defined categories:
the larger  lakes (at least 20 meters deep and with a
minimum  surface  area  of  500,000  square  meters)
and small  lakes (less than 20 meters deep and with a
surface  area  of less  than  500,000  square  meters).

      1.  The original state of larger lakes

   Today there  is  fortunately still a number of large
lakes that  have completely  preserved their  original
state  — or practically  so.  Thanks to their depth,
they have  a large quantity of hypolimnic  water at
their  disposal.  The blue or greenish-blue water is
clear and transparent  and its content of phosphorus
compounds is so low that plants  cannot make use of
the available nitrates.  There is only a quantitatively
moderate  development of phytoplankton organisms
even in the surface water, and littoral plant production
is   also slight.  The high permeability of light pre-
vents the formation of a distinct thermocline and pro-
vides the plants with good conditions for development
even at great depths.

   The lime content and the oxygen content  of these
lakes are approximately the same from the surface
down  to the  greatest depth, and there is  no dis-
appearance of oxygen in deep water.  Ammonia, iron,
                                                   299

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300
                         THE ARTIFICIAL EUTTOPHICATION OF OUR WATERS
manganese, and hydrogen  sulphide  are  also  absent
there.   Littoral plant growth and phytoplankton pro-
duction are very slight during the whole year, in con-
trast to the deep fauna, which is comparatively rich.
Fish present are mainly Coregonen.

      2. The original state of small lakes

   In  a  small  lake  without  human  influence  the
tributaries  and wind  bring far more dead leaves,
pollen   grains,  insects, and  other  organisms  per
square  meter  of lake  surface  and per cubic meter
of volume than in a large lake. These dead organisms
and parts of organisms decompose in the water and
release fertilizers, resulting in the increased develop-
ment of plankton and shore algae.  Because of this,
oxygen  disappears and ammonia, iron,  manganese,
and  hydrogen sulphide  appear  in the deeper water
during summer stagnation, without human influence.

   B. The original state of rivers

   In rivers that  are not contaminated by sewage, we
generally  expect  clear, bluish  water;  only  in boggy
regions is it brownish.   The stones  on the river bed
are  only  very  slightly overgrown with  algae, if at
all.  The concentration of oxygen is neither very high
nor very  low.  Such rivers are suitable for  develop-
ment of fishing and also for drinking water supplies
or for  swimming.

n. The consequences of pollution by sewage

   A. The consequences of pollution in lakes

   Unpurified  sewage is noted by the turbidity and
discoloration of the lake water and, in serious cases,
by the presence of paper  and other solid substances
and also of oil. Bacteria as well as plankton and shore
algae develop rapidly.   Small  lakes  react quickly to
the introduction of sewage. Oxygen rapidly disappears
in the  hypolimnic water. Complete disappearance of
oxygen can also occur in large lakes in varied places:
(a) In  the  water  just above the mud on the bed, (b)
in the lower part of the metalimnion,  and (c) in places
on the shore where masses of algae have been driven
and  have  then  rotted (Thomas 1955a, 1960a).  The
unfavorable proportion of oxygen  in such lakes en-
dangers or destroys the stocks of valuable Coregonen
so that it is impossible to develop the lake for fishing.
The preparation of drinking water from polluted lakes
is rendered difficult, and swimming cannot be allowed
in the proximity of sewage outlet pipes.

   B. The consequences of pollution in rivers

   The banks of rivers, in contrast to lakes,  are very
extensive in comparison with the surf ace. Aesthetically
unpleasant conditions therefore annoy residents on the
banks, fishermen, swimmers,  and walkers on both
sides  of the  river.   In this  respect I am thinking
not only  of papers, rags,  etc.,  but also  of  turbidity
and discoloration.

   Changes  in  the biocoenoses   of  the river bed
caused by sewage and the appearance of polysaprobic
organisms such as SphaeroHlis are also strikingly
visible; rapidly growing tufts of Spkaerotilis are con-
tinually broken off by the current  and transported
long distances.  According to Kolkwitz and Marsson
(1908,  1909) and  Kolkwitz (1950), water must flow
for a  considerable distance before self-purification
brings a more favorable state of biocoenoses; bacteria
and other  heterotrophic  organisms  recede in favor
of algae, the oxygen  content  of the water  increases
and  the condition of  the  water  improves  again.

   River pollution makes obtaining drinking water and
using  river water for  industrial  purposes  more
difficult.  Where  ground water is fed through rivers,
it can  be  rendered useless  by pollution.   Only un-
polluted rivers are  suitable for swimming.   The
pollution of  a river means partial or total depreciation
of the stream for fishing purposes,

HI. The first results of purifying sewage

   A.  Results of purifying sewage in lakes

   The  opinion is very widely held today that sewage
to be  discharged  into lakes  and rivers  should be
purified not only  mechanically but also biologically.
Special purification to remove  fertilizers  is seldom
used.    The following ideas start, therefore, with the
assumption  that  sewage  discharged  into  lakes and
rivers  should be purified  mechanically and also
biologically.  The  method of sewage purification put
forward prevents  any direct  visible pollution of the
lake shores, with the exception of scum originating
from detergents, about which I shall not speak here.
From  an aesthetic point of  view it is especially
important that the natural water of lakes from which
supplies of  drinking water  are taken is not polluted
by sewage.

   The  content of bacteria, particularly the Bacterium
coli  group, in biologically  purified sewage is much
less than in  unpurified  sewage.  For this reason,
water  near the shores  of a lake that receives no
unpurified sewage is much more suitable hygienically
for swimming.

   B.  Results of purifying sewage in rivers

   The aesthetic and hygienic results of sewage puri-
fication for lakes are also applicable to rivers.  In
rivers, moreover, it is relatively  easy to  get rid of
the heterotrophic  living  communities caused  by un-
purified sewage by simply purifying the latter.  At the
same   time it is  possible  to improve the  oxygen
content of river  water effectively and  permanently,
providing thereby  more favorable living conditions for
fish.   The death of fish due to purification of sewage,
can, however,  occur.

IV. Conditions for permanent improvement  of  the
    state of rivers and lakes

   Unfortunately, mechanical and biological purification
of sewage cannot alone prevent the enormous develop-
ment  of algae  and higher aquatic plants.  Biologically
purified sewage still contains some  substances that
actively further the growth of certain green  plants.
What kind of substances are these?

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                          The Eutrophication of Lakes and Rivers, Cause and Prevention
                                               301
   In 1945  and later, I  grew phytoplankton  cultures
both  in lake water and  in waters  to which nutritive
substances  were added.   These tests showed that the
content of  nitrogen  and phosphorus  compounds in
surface water  of eutrophic lakes varies considerably
in the  course  of the year  whereas  the potassium
content is more constant.  Because of the dominating
position  of  nitrogen  and   phosphorus  compounds,
the  importance  of trace  elements  or  of growth
substances  and other  organic substances was pushed
into the  foreground.   For  these  reasons,  I asked
myself  the  following questions:  Is the concentration
of  all  other  vital  substances  sufficient to allow
correspondingly increased production of algae where
the supply of nitrogen and phosphorus is artificially
increased?   Is  a considerable part of  the  added
nutritive  substances that are used incorporated in
organic form?

   These  questions were experimentally tested by
adding  surplus nitrates  and phosphates  to  samples
of water from 46 different lakes.  We filled two to six
Erlenmeyer flasks each with 300  milliliters of  dif-
ferent lake water and sterilized them after  stopping
the flasks with  cotton.  We then added sufficient sterile
nitrate  and phosphate  solution to each flask to bring
the nitrate  content to 20 milligrams per liter and the
phosphate content to 2 milligrams  per liter.  Surface
plankton  from  the mesotrophic  Upper Lake  Zurich
served  as  the  inoculum for these sterile nutritive
solutions.  Since the surface water  composition in this
lake is considerably different in summer than in winter,
the water was tested once in summer and once in
winter (Thomas, 1953).

   The  injected flasks remained for 2 months in dif-
fused light and  at room temperature. At the end of the
test period,  the plankton algae and tychoplankton had
greatly increased  in  all the  flasks.   The  nitrates
had been  completely used up in  almost all the tests
and  the phosphates in some  of  them.  The addition
of nitrate and  phosphate  to water  from lakes  tested
is, therefore, sufficient to further the growth of algae
considerably. In other words, only nitrates andphos-
phates come into question as minimum substances in
such lakes.  Here minimum substance means the vital
nutritive  substance that checks the further develop-
ment of algae by its deficiency in the water.

   The mechanical/biological sewage purification used
today, however, removes from sewage only a small
part  of the  effective  nutritive  material  for  algae.
Algae, being autotrophic  organisms, can - as is well
known - use such mineral substances to increase their
own body  substance and thereby increase  the number
of individuals.
   The  tests described prove  only that the  addition
of nitrogen  and phosphorus  compounds to lakes and
rivers is  sufficient to stimulate some types  of algae
to greatly  increased  growth,  which  can, however,
have very detrimental results.
   A. Conditions for the permanent improvement of
      the  state  of lakes.
   As has been mentioned, purification of the sewage
will  improve  the  waters  on  lake  shores  where
sewage has a direct  effect.  Without doubt, however,
the biggest problems arise from the proliferation of
plankton algae and of shore  algae  (Thomas, 1960a,
1960b, 1961).

   Plankton algae make the water turbid and discolored
with unpleasant shades of green, yellow, brown, and
violet.   The  floating layers of plankton algae are
particularly  disagreeable for  swimmers, boaters,
fishermen, inhabitants on the banks, and people walking
nearby.  Shore algae also are often unpleasant.  On
Lake Zurich in Switzerland, and on other lakes with
a  similar  supply of fertilizers, the stones on the
shore  are  covered  with brown  clumps  of Diatoms
several  centimeters  in  extent even in early spring.
At  about  the  same  time,  Cyanophyceae  (mainly
Oscillatoria  limosa Ag)  overgrow all places where
the surface consists  of mud or lake chalk.  On these
blackish areas there is also a more or less plentiful
growth of siliceous algae.  Abundant CO£ assimilation
occurs when the  sun is shining.  Part of the released
oxygen is held back in the entanglement of cyanophycian
threads in  the form of bubbles.  These  gas bubbles
finally result in  patches' larger than hand size being
detached from the bottom so that  they  float on the
surface and form repulsive flat cakes there that look
like the  skin of a toad.  This unpleasant phenomenon
is overcome only by rain and wind in April or  May.
The original biotopes of the  "toad's skin" are then
overgrown  by other  algae, particularly by extensive
Spinogyra  cushions, which then rise to  the surface
of  the  lake  in  summer  and disfigure  the shores.

   In April or earlier, according to the weather, the
stones  near the  shore become covered  with a fine
growth of  Vlothrix threads.   From about May  until
July all places  on  the  shore are dominated by the
green  thread algae.   At the  same  time  Cladophora
threads  growing  on  stones,  wood, reeds,  etc.,  at
depths of up to 3 meters, press up towards the surface
of  the  lake  accompanied by, among others, Rhizo-
cloniwn, Microspora, Oedogonium,   Mougeotia,   and
Zygnema.  The latter three may reach their maximum
growth somewhat earlier. If the weather is favorable
for the growth of Cladophora, the stony shore zones
from 0 to  about 3 meters deep  are packed with the
cotton masses of its threads.  Oxygen  bubbles re-
leased by assimilation raise some  of the Cladophora
pads to the surf ace of the water in sunny, calm weather,
and yellowish-green layer forms, often  many centi-
meters thick.
   These tenacious,  extensive  masses of Cladophora
that cover large areas of a lake are definitely annoying
to everybody who comes  in contact with them.   But
even worse is the annual  damage to  reeds. Formerly
reeds  swayed  backwards and forwards  in storms
with the rise  and fall of the waves, but today they
are  snapped off  by  the  Cladophora masses in the
border  zone  of  the  open  water  and are pressed
below  the   surface.    Later,  the  stalks that  have
been pressed down often produce  adventitious shoots,
which, however, die in the winter. The reed rhyzomes
in the  ground are so weakened by this process that
they produce  no  stems   the following year, or  so
few that they  can offer  still less  resistance to the
new masses of algae.  This has resulted in a great

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 302
                          THE ARTIFICIAL EUTROPHICATION OF OUR WATERS
decline in the  growth of reeds on the shores of Lake
Zurich,  which  is disadvantageous  for  fishing and
regrettable from  an aesthetic  point of view.   In
addition  to  damaging  the  reeds,   the  Cladophora
masses can cause an extreme lack  of oxygen on the
shores that  is recognizable by the evaporation  of
hydrogen   sulphide  and other  products of decom-
position,  and leads to troubles in the shore regions.
Warm, calm  weather with some rain and a lack of
sunshine  furthers  the dying off  and  rotting away  of
the Cladophora and leads to the disagreeable condition
mentioned.

   Since the main masses  of green  thread algae die
generally  in July  and August,  there was formerly
a  period  in autumn when  there  were comparatively
few  shore algae.   But 1961 brought a new surprise
to Lake  Zurich.   In September and October con-
siderable quantities of Hydrodictyon reticulatum de-
veloped in  various places  on the shore.   The net-
work of this algae that at first floats on the water is
later  thrown  onto  the  dry beaches by the  waves
and  forms an unsightly   line at the  water  level.
Masses of plankton algae  and shore algae also have
a  directly detrimental effect, but even worse are the
effects when they die off in the lake.  The most serious
is the  resulting lack of  oxygen just above the bed
of the lake in  the metalimnion (possible also in the
whole  hypolimnion) and in the surface water near the
shore.  The nitrogen and  phosphorus combinations
set  free  from  the  dead algae  return  to the cycle
again  and promote the development of more  algae.
An important  conclusion is drawn from this  know-
ledge: only if  it is possible to reduce  considerably
the  superabundant production of plankton and shore
algae  in a eutrophic lake  can a permanent improve-
ment in the state of the lake be achieved.

   B.  Conditions for the permanent  improvement  in
       the state of rivers

   Contrary to circumstances in lakes, the mechanical/
biological purification of sewage discharged into rivers
usually remedies the lack of oxygen - at least where
the current is strong enough.  In rivers with abundant
nitrates  and phosphates,  algae  and  higher aquatic
plants develop  rapidly. Where the current is strong,
the  problems  created  by  such  algae are the least
serious.  In the stretches of river that are naturally
slow flowing, however, mainly higher aquatic plants
develop.  For  fishing, a thick growth of weeds leads
to deterioration and affects the  sport.   The flow of
water  is  also   checked, which leads to  an increase
in the average water level.  Swimming is impossible
in such  rivers.  A vigorous proliferation of algae
and  aquatic plants lines the bed, so  to speak,  with a
fur of organic  material.  The surface of the fur may
have fresh water running over it continuously so that
it  offers animals  favorable living conditions.  On the
underside of the fur, however, decomposition processes
are  already taking place  and a layer lacking oxygen
is developing.   This applies especially to species
between  stones as well as in stagnant corners and
holes  in  the  stream bed  and  also   in  the cavities
made by fish for  spawning.  If the spawn is covered
over with mud, the eggs will be destroyed by fungi and
bacteria.
   The silting of the river bed is also disadvantageous
to the condition of  ground  water  used for  drinking
water or for commercial purposes.  Replenishment of
the ground water  supply is made more difficult, and
the water  draining from  a river  choked with mud
has less oxygen than an oligotrophic river does.

   Plant nutrients  are especially undesirable inrivers
where the  flow is  used for producing electricity.
Where the water  flows into a pressure main,  the
original  river bed has  very little water, so the force
of the current is less and allows an especially striking
development  of undesirable algae.  If  an attempt is
made to maintain the original water level by damming,
the growth  of weed and algae occurs particularly
where the depth of  the water is  less than 2 meters.
If water from a river rich in  nutrients is used for
producing electricity,  there  should be an  adequate
quantity of water (residual water) in the original river
bed - not only to preserve the  natural beauty  but
also  to  protect the  river  itself.  The mechanical
and biological purification  of sewage discharged into
lakes and rivers cannot, in either case, be  regarded
as a permanent measure to  improve their state unless
the minimum nutrient substance is removed  from the
sewage.


V. Means of permanently improving the state of lakes
   and rivers
   A. The permanent improvement of the state of lakes


      1.  Prevention of sewage discharge

   There are lakes where the eutrophic condition is
wholly or mainly caused by the discharge of sewage
from the communities  on their  shores.   The surest
way of  improving the condition of such lakes is to
collect  the  sewage of  all the  communities  in large
pipes, purify it,  and discharge it into  the lake at
its outlet.   As a rule, such a system of drainage will
have to surround the lake (circular drainage  system).

   On Lake Zurich, the sewage  formerly discharged
into the lake, from part of the town  itself and also
from the communities of Kilchberg and  Zollikon (a
total  of over  50,000  inhabitants),  for the  past  50
years has been collected into  drains and discharged
into the lake  at its outlet.  Actual circular  drainage
systems to  conduct  sewage  to  the outlet  of lakes
have  been planned in various places,  e.g.,  the Lake
of  Hallwil  in  Switzerland and the  Lakes of Tegern
and Schlier in Bavaria.  Since circular drainage for
sewage generally requires more  pumping, the running
costs  are   considerably increased.    Lohr  (1961)
reckoned with an  annual expenditure of DM 18 (4
dollars) per inhabitant.   Where  there is not a great
deal  of water  at the  outlet  of the  lake,  thorough
purification is of special importance;  otherwise new
difficulties will arise.   In large lakes with long and
irregular shore lines and in lakes where the outlets
are already  rich in nutrients, the effective discharge
of  the  nutrients into the lake outlet  is  difficult.  In
the following comments, therefore, other possibilities
of combating eutrophication of lakes  are discussed.

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                        The Eutrophication of Lakes and Rivers, Cause and Prevention
                                               303
      2.  Nutrients removal from sewage

   The removal of all the salts regarded as fertilizers
cannot be dealt with here.  Generally speaking, it is
sufficient to remove the minimum substances, or the
purification of the  sewage can be such that a definite
and important nutritive substance becomes a minimum
substance in the lake.  In my opinion, in the test areas
known to me, phosphate is most suitable for removal
for the following reasons (Thomas, 1949,  1956/57):
   1.  Phosphate  is  present  only in small quantities
      in oligotrophic lakes in the Zurich area;
   2.  the natural tributaries running into these  lakes
      contain  very  little  phosphate as long as  they
      are not subjected to human pollution, but contain
      large  quantities of nitrate;
   3.  rain water often contains  large quantities of
      nitrogen  compounds  that can be  utilized by
      plants;
   4.  bacteria  and  blue algae living in the water are,
      under certain conditions, able to combine gaseous
      nitrogen organically;
   5.  a high percentage  of  the  nitrogen compounds
      from  the putrefying  parts  of organisms return
      to  the  cycle of  substances  as  phosphorus
      compounds;
   6.  phosphates can be more readily eliminated from
      sewage than nitrogen compounds (for tests con-
      cerning the elimination of nitrogen from sewage
      cf.  Bringmann, 1961).

   One recommended method of eliminatingphosphates
from  sewage is with aluminum sulphate (Lea, Rohlich
and Katz, 1954),  Another method iswithiron chloride
(ferric  chloride) or a  mixture of  iron chloride and
iron sulphate  (Thomas, 1955b).  In the  mechanical/
biological purifying plant on Lake Greifensee, Switzer-
land,  80  to 90 percent of the phosphates have been
eliminated  with  ferric chloride  (partly  mired  with
ferric sulphate) for the last 3 years.  At present the
plant  purifies the sewage  from about a 20,000 popu-
lation. Since some  communities are still discharging
unpurified sewage into the lake, the condition of the
lake is not yet permanently improved.
   If the sewage from an industrial plant is very rich
in phosphates, it should  be  utilized for  agriculture
or precipitated within the  plant.   The  higher  the
phosphate content of the sewage, the more expensive
it is   for  the  community to  purify  it.   If 80 to 90
percent of the phosphates is precipitated in a purifying
plant  during the whole year, the  additional cost in
the Canton of  Zurich amounts to  about  50 cents
to a dollar  per head, if the process developed by the
author is used (a saving of about 50 percent).

      3. Intensive development of fishing
   As long as the conversion from organic substance
into fish  meat  is  possible  in a lake, advantageous
use is made of the  fertilizers.  Removing fish from
lakes  means a step  towards preventing eutrophication
(Thomas, 1944).

      4. Algae and higher plant removal

   Where green thread algae  (Cladophora, Rhizo-
clonium, etc.) or higher aquatic plants (Potamogeton,
etc.) profilferate abundantly on the shores, as many
of  these  plants as  possible  should be  pulled  out
by boats and then destroyed on  the  shore.  This not
only improves  conditions in the  lake but also con-
tributes to the prevention of eutrophication because
decaying algae in the  lake release fertilizers.


      5. Chemical intervention in  lakes

   Tests on  Cladophora  and Rhizoclonium  cultures
showed that  these algae are very sensitive to zinc
and copper salts (Thomas, 1962).  I have never heard
of combating algae on lake shores with zinc salts.
Copper sulphate  is used  (e.g., near  bathing beaches
on  the  Lake of  Zurich) to destroy the  water snail
Limnaea auricularia  L., which is attacked by trema-
todes and annoys swimmers by releasing Cercarias.


   Algae poisons might possibly be used successfully
at individual places on the lake shore; however,  if the
algae are not attacked all round the shores of the lake,
the wind  can still blow  algae growing in one place
to any other  point. Toxic substances used to control
algae can  also  damage  all other shore organisms
as  well  as humans,   especially where the water is
used for drinking purposes.

     6. Aeration of deep water in lakes

   Attempts to aerate deep water in lakes have already
been made in both America and  Europe.  Extensive
tests have  been made in Lake Pfaffikon, Switzerland
(results not yet published).  Air  blown into the deep
water is brought upwards by the rising air bubbles
and becomes  partly  mixed with  the surface water.
During the summer,  the epilimnion thereby becomes
colder  and the  deep water  warmer.  Since  trouble-
some fertilizers remain in the  lake,  however,  the
mass development of algae begins  again and  when
it decays there is a  sudden decrease  in the oxygen
content.   The artificial warming of the  deep water
achieved in this way is undesirable for drinking water
supplies.  The  unstable conditions produced also en-
danger fish life.

     7. Drawing off deep water

   Pumping or  siphoning off deep water to the outlet
of the  lake during the summer period of stagnation
removes part of the excess fertilizers present in the
hypolimnion.  During this process, water lacking oxygen
is replaced by that rich in oxygen. The layer  of warm
surface water that has plenty of oxygen can be some-
what increased  by drawing off  the deep water - a
process that is easy to regulate and control. (Thomas,
1944, p.194;  1948, p.175;  1956/57, p.207).  Olszewski
(1961)  gives  a  good   example  of  the practical ap-
plication  of  this method.   To  avoid  harm  to the
epilimnion  by  secondary oxygen consumption,  the
layer drawn  off in the  first year should not be too
deep.

   Drawing off  deep  water  is  the most successful
method of  artificial intervention  in lake conditions.

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304
THE ARTIFICIAL EUTHROPHICATION OF OUR WATERS
      8. Transferring  fresh  water  to  lake  depths
        where the oxygen content is low

   This treatment produces results similar to those
achieved by blowing air into the deeper parts of lakes.
There is no decrease  in the fertilizers present in the
lake so no decrease is expected in the growth of algae.
In my opinion,  this  method  is  recommended only
in  special  cases  and not as  a general  means of
improving the condition of lakes.

   B. Permanent improvement in the state of rivers

   If  all sewage going into a river is mechanically
and biologically purified, the  condition of the water
and degree of purity can be considerably improved.
But, as has already been mentioned,  there will still
be troubles and damages caused by plant nutrients.
Should we also eliminate in our rivers the proliferation
of plants caused by nutrients? Most people concerned
with the  eutrophication of rivers - whether they are
experts on the subject  of water or outside observers -
expect the proliferation of photosynthetic organisms in
rivers to  be extensively prevented  by measures for
preserving the purity  of natural stretches of water.
Taking  this  into consideration  I  believe  that  we
should spare  no  efforts to prevent proliferation of
aquatic  plants and algae in rivers.  What means have
we of accomplishing this?

      1. Protection of water-tapping areas and places
        used for swimming

   Water-tapping areas or  swimming areas near in-
habited places can be protected by discharging sewage
into the  river  below  these points.   This, however,
means that the improvement is only local.

      2. Elimination of phosphates from sewage

   It  has  already been mentioned that phosphate is
the most  suitable for removal of any of the fertlizers
as far as lakes are concerned.  For the same reasons
it is also recommended that phosphates be  eliminated
as far as possible from sewage discharged into rivers.
It is  hoped that this will reduce the growth of algae
and aquatic plants.
                                  3. Intensive development of rivers for fishing

                               The development of rivers for fishing, at least in
                             Europe, is  already under way.  It is hardly to be ex-
                             pected that an increase in river fishing would result
                             in any appreciable decrease in the growth of plants.


                                   4. Removal of algae and higher plants

                               In rivers very much overgrown with aquatic plants
                             it is necessary, at least locally, to cut out the plants
                             and remove them from time to time.  This is difficult
                             and expensive but it has immediate results.  Without
                             this measure, the decaying plants in the deeper parts
                             of the river cause damage.


                                   5. Chemical intervention in rivers

                               In  Europe there has been little experience of re-
                             ducing plant  growth  in rivers by poison.  In small
                             streams  in  Zurich used for breeding trout,  green
                             thread algae were eliminated with Dowpon, without
                             harm to the fish.


                                                SUMMARY
                                A plentiful supply of fertilizers reaches algae and
                             higher aquatic plants in rivers and lakes by means of
                             sewage - even when this is  mechanically  and bio-
                             logically purified.   Nitrates and phosphates,  which
                             are particularly  important  as fertilizers, stimulate
                             the growth of algae and higher aquatic plants, which
                             leads  to manifold damages and complications.  A direct
                             measure against thi eutrophication of river sand lakes
                             that promises great success is the thorough removal of
                             phosphates from the  sewage.  Where considerable
                             quantities  of  phosphates  reach  the   sewage from
                             industrial  areas they  should, where  possible,   be
                             removed from the sewage  within the  plants, or the
                             sewage  that is rich in phosphates should be  used for
                             agricultural purposes.  Reference is made to some
                             further  aids  to prevent the eutrophication of lakes
                             and rivers.  The special limnological character of
                             each type of sewage must be considered when choosing
                             preventive measures.
                                             REFERENCES
Gesetz betreffend die offentliche Gesundheitspflege and
die Lebensmittelpolizei vomlO. Dez. 1876; Verwaltung
des Kantons Zurich.

Verordnung betreffend die Reinhaltung der Gewasser
vom 1. Juni 1881; Verwaltung  des Kantons Zurich.

Bringmann, G., 1961. Biologische Stickstoff-Elimi-
nierung aus Klarwassern. Gesundheits-Ingenieur, 82.
Jehrg., p. 233-235.

Forel, F.A., 1901.  Handbuch der Seekunde, 249 p.;
Stuttgart,  Verlag J. Engelhorn.

Kolkwitz, R., 1950. Oekologie der Saprobien. Schriften-
reihe des  Ver.  Fur Wasser-, Boden- undLufthygiene,
Berlin-Dahlem, Nr.  4;  Piscator-Verlag Stuttgart.
                             Kolkwitz, R., und Marsson, M., 1908.  Oekologie der
                             pflanzlichen   saprobien.  Ber.d.deutsch,  Bot.  Ges.,
                             26, 505-519.


                             Kolkwitz, R.,und Marrson  M.,  1909.   Oekologie der
                             tierischen  Saprobien.    Int. Rev. Ges.  Hydrobiol.
                             Hydrogr,, 2, 126, 152.

                             Lea,   W.L.,  Rohlich,  G.A., and  Katz,  W.J.,  1954.
                             Removal of phosphates from treated sewage. Sewage
                             and Industrial Wastes, 26 p 261-275.


                             Lohr, M.,  1961.   Gewasserschutzbestrebungen des
                             Landes Bayern.  Verband Schweizerischer Abwasser-
                             fachleute, Verbands-Bericht Nr. 71/1,  195.

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                        The Eutrophication of Lakes and Rivers, Cause and Prevention
                                              305
Olszewski, P.,  1961.  Versuch einer  Ableitung des
hypolimnischen  Wassers  aus einem See. Verb. Int.
Verein. Limnol., XIV, 855-861.

Sawyer,  Clair  N.,  1944.   Biological engineering  in
sewage treatment.   Sewage and Industrial Wastes,
16, p.955-935.

Sawyer, Clair N., 1952.   Some new aspects of phos-
phates in relation  to lake fertilization,  Sewage and
Industrial Wastes, 24, p. 768-776.

Sawyer, Clair N., 1954.  Factors involved in disposal
of sewage effluents to lakes.  Sewage and Industrial
Wastes, 26, 317-328.

Thomas, E.A., 1944.   Ueber  Massnahmen gegen die
Eutrophierung unserer Seen und zur Forderung ihrer
biologischen  Produktionskraft. Schweiz.   Fischer-
eizeitung, Nr. 7/8, 8 p.

Thomas,  E.A.,  1948. Limnologische Untersuchungen
am Tiirlersee.  Schweiz.  Z. f.  Hydrol XI, 90-177.

Thomas, E.A., 1949.  Regionallimnologische Studien
an 25 Seen der Nordschweiz. Verh. Int. Ver.  Limnol.,
10, 489-495.
Thomas, E.A.,  1953.  Zur Bekamfung der See-Eutro-
phierung:  Empirische  und  experimentelle  Unter-
suchungen  zur  Kenntnis  der Minimumstoffe  in 46
Seen  der Schweiz und angrenzender Gebiete. Monats-
bull.  Schweiz.  Ver. Gas-und Wasserfachmannern, Nr.
2/3,  15 p.
Thomas,  E.A.,  1955a.   Ueber die  Bedeutung der
abwasserbedingten direkten Sauerstoffzehrungin Seen.
Monatsbull.  Schweiz. Ver.  Gas-und  Wasserfachm.,
Nr. 5, 119-129.

Thomas, E.A., 1955b.  Phosphatgehalt der Gewasser
und Gewasserschutz. Monatsbull. Schweiz. Ver. Gas-
und Wasserfachm., Nr. 9/10, 16 p.
Thomas, E.A., 1956/57. Der 7iirichsee, sein Wasser
und  sein Boden. Jahrbuch vom  Ziirichsee,  173-208.

Thomas, E.A., 1960a.  Sauerstoffminima und Stoff-
kreislaufe  im  ufernahen  Oberflachenwasser   des
Zurichsees  (Cladophora-  und Pkragmites-Gurtel).
Monatsbull.  Schweiz. Ver. Gas- und  Wasserfachm.,
Nr. 6, 8 p.

Thomas, E.A., 1960b.   Rotalgenrasen und Blaual-
gentappiche  im  Ziirichsee. Vierteljschr.  Natf. Ges.
Zurich,  105, 297-305.


Thomas, E.A.,  1961.   Hydrodictyon rettctdatum und
seine Beziehung zur Saprobitat  im Ziirichsee und in
der  Glatt.   Vierteljschr.   Natf.  Ges.  Zurich, 206,
225-235.

Thomas, E.A., 1962. Zink im Trinkwasser alsAlgen-
gift (Cladophora und Rhizoclonium) Archiv fur Mikro-
biologie, 42, (3): 237-245.

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306
THE ARTIFICIAL EUTROPHICATION OF OUR WATERS
                      THE BIOLOGICAL REMOVAL OF NITROGENOUS COMPOUNDS

                              FROM SEWAGE TREATMENT PLANT EFFLUENTS
                                          William M. Beck, Jr.*
              CONDUCT OF THE STUDY

   From the previous talk it should be  obvious that
the increasing nutrient content of our inland waters
is becoming a major problem.   That  sewage treat-
ment plant  effluents  are  in  part  responsible  is
unquestioned.

   In the summer  of 1959 a  pilot plant study was
organized at the  Orlando, Florida, sewage treatment
plant for  the  purpose  of evaluating methods   of
removing nutrient compounds biologically.  For this
study a  two-section sludge-frying bed was covered
with a  thin  layer  of  well-digested  sludge  to stop
seepage. A metered portion of the final plant effluent,
prior to chlorination, was diverted to this bed.

   The Orlando plant is  well designed and skillfully
operated. Treatment consists of primary clarification,
sludge digestion, two-stage trickling filtration, and
secondary  clarification.    The final  effluent,  prior
to chlorination,  had an average  biochemical oxygen
demand of 8 milligrams per liter.

   During July 1959, three  weeks were  devoted to a
study of biological  removal of nutrients  in this pond.
Producers consisted of  an almost  pure culture  of
Chlamydomonas  sp.  Because of our active changing
of retention time in the pond no attempt was made to
measure the quantities of algae. Consumers consisted
of  Cfiironomus decorus   and  C.  fulvipilus  (34,992
per square meter, of which an estimated 95% were the
former   species  and 5% the latter).   These figures
are based on a single sample (0.5 ft 2).

   Retention time was either increased or decreased
every few  days to  obtain data about the relationship
between  loading  and biological removal of nutrient
elements.  It is realized that such frequent changing
did not  necessarily permit a  full biotic  response to
the  altered conditions; however, results show that
such response did occur.

   Analytical  determinations  were   made by Mrs.
Foymie  S.  Kelso and Mr. Marvin L. Wicker, Florida
State Board of  Health.   My  own work consisted of
chemical and biological sampling, and determination
of dissolved oxygen,  pH,  and temperature during the
night sampling.   "Standard Methods" was followed
in chemical determinations.

   It  is a pleasure  to  acknowledge the complete
cooperation and generous assistance  of Mr. J. Howard
Worsham, Superintendent, Orlando Sewage Treatment
Plant, and of his associates.

   Samples were  obtained  hourly  from the  pond
influent and effluent.  Dissolved oxygen, pH, and tem-
                             perature were determined immediately and nutrient
                             analyses were made on 24-hour composites.  Nitrate,
                             nitrite, and ammonia analyses were made separately
                             and the results combined and reported as total nitrogen.
                             Both orthophosphate and total phosphate analyses were
                             made; these results were not reported because of poor
                             efficiency  of  biological removal.   Effluent samples
                             were  filtered through paper  with  a low vacuum to
                             remove algae.

                                                  RESULTS

                             Table 1. TOTAL NITROGEN REMOVAL

Date
(July)
8
9
10
13
14
15
16
17
20
21
22
23
Influ-
ent,
mg/liter
11.5
13.4
13.0
14.4
14.8
14.0
12.9
14.0
13.4
15.1
12.3
14.8
Maximum
Mean
Minimum
Efflu-
ent,
mg/liter
4.9
1.4
1.8
10.1
9.1
9.3
6.5
7.6
7.8
5.2
2.5
2.2
15.1
13.6
11.5
Re-
moval,
%
57.4
89.6
86.2
29.9
38.5
33.6
49.6
45.7
41.8
65.6
79.7
85.1
10.1
5.7
1.4


Gal/ day
70,000
33,000
29,000
111,000
111,000
70,000
76,000
77,000
77,000
40,000
34,000
40,000
89.6
58.6
29.9
Reten-
tion,
days
1.12
2.38
2.71
0.71
0.71
1.12
1.03
1.02
1.02
1.96
2.40
1.96



                              Table 2.  CHEMICAL AND PHYSICAL FACTORS
Maximum
Minimum
02,
mg/liter
35.7 a
0.0
pH
10.6
6.7
°C
34.5
26.0
                              a At 34.4°C = 496% saturation.
                                                 DISCUSSION

                                 As will be  seen from Table 1, removal of total
                              nitrogen ranges from a minimum of 30 to a maximum
                              of 90  percent.    Figure 1  shows the  relationship
                              between  retention  time  and  percentage  removal.
                              Maximum nitrogen removal  occurs  with 2  to  2.5
                              days' retention.   Total  phosphate removal is much
                              less  efficient, although there is a direct relationship
* Florida State Board of Health.

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                             The Biological Removal of Nitrogenous Compounds
                                                307
between  phosphate removal and retention time.   As
in the case of nitrogen, phosphate removal varied
directly with retention time.
   To  support  our contention that the  algae  crop
harvested itself by oxygen flotation, we decided to at-
tempt  agitation  of the pond just prior to the oxygen
    90
    80
    70
    60
  Q
  111
    40
    30
    20
                     1              2
                  RETENTION TIME, days
   2400 0200 0400 0600  0800 1000 1200  1400 1600' 1800  2000 2200 2400
                        HOURS
Figure 1. Relationship between  retention time and percentage of
        total nitrogen removal.
Figure 2. The diurnal cycle for dissolved oxygen  and pH, July
        14 to 15.
                 OBSERVATIONS
   Figure 2 presents  the  diurnal cycle for dissolved
oxygen  and  pH.   The  oxygen  curve  is especially
interesting.  Following  a  minimum  concentration of
dissolved oxygen just before dawn there is a rapid
increase,  with  super saturation  occurring by  0900
hours.   The peak was  reached at 1500 hours.  The
rapid drop after 1500 hours represents a phenomenon
that occurred  several times during the study.   The
entire pond, without  warning,  starts to effervesce.
This results in oxygen flotation of virtually the entire
crop  of  algae.  The algae  may then be removed by
skimming.  As noted  in Figure 2, this effervescence
resulted in an excessive  loss  in oxygen and a sub-
sequent increase in dissolved oxygen prior to sunset.
This  was  due  to agitation by a thunder shower.  On
no  other day did this occur. The shower did not put
the algae back  into suspension.
peak at 1500  hours.   We  did  not  want to disturb the
layer of sludge on the bottom of the pond. Finally we
resorted  to  the  use  of an old-fashioned, vibrator-
type automobile  horn  and  a  storage battery.   The
horn, wrapped in  thin polyethylene and  immersed
in the pond,  was  honked briefly, and produced ef-
fervescence and algae rise in a small area.

                  CONCLUSIONS

1. Removal  of  total  nitrogen by the  methods re-
   ported here reaches a high level under properly
   controlled  conditions.

2. More efficient methods of  removal  of phosphates
   are needed.

3. The results obtained in this project warrant  more
   careful study.

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308
                          THE ARTIFICIAL EUTROPHICATION OF OUR WATERS
                                              DISCUSSION
   The  greater  part  of the discussion dealt with
methods  of removing phosphates  from waters.  A
three-stage process was described in which there is
primary clarification followed by the addition of ferric
chloride and aeration  to precipitate the phosphates.
The  stage is followed by  settling.   One discusser
suggested that the  addition of ferric chloride at the
middle stage would be uneconomical because of the
adsorption of  iron  and suggested that the addition of
sand  at this  stage would be better.  It was stated,
however,  that  the  addition  of sand would  result in
too much sludge, and, therefore, would be uneconomical
from that  standpoint.

   A report was made that Sweden has been experi-
menting with a flotation method of removingphosphates
by employing  supersaturated water under pressure.
This method provides  for  over 90  percent phosphate
removal, and if a flocculent  is added, better results
are realized.  Other experimental work was discussed
in which water hypacinth was used to remove phos-
phates and nitrogen.  Little success was  realized,
however.

   In  discussing  the eutrophication of lakes, a state-
ment  was made that if  the  phosphate levels can be
maintained  below  20  ppb,  algal blooms will not
ordinarily  be encountered.  The  chemistry of each
body of water, however, must be considered separately.
The point was also made that phosphate removal alone
cannot  guarantee elimination of algal blooms, but
nitrogen must also be considered,  especially since
some of the  algae are  capable of fixing atmospheric
nitrogen. Some success is being realized in eliminating
eutrophication in Florida lakes with aeration.

The Artificial Eutrophication of Our Waters -
Discussion

   An  inquiry was made regarding the definition of
an  algal  bloom.   Some felt that the  algal growth
must cover the  whole lake and not just part of it to
be considered a bloom.  Mention was made of the
Great  Lakes, however,  where  algal  growths cause
considerable problems,  and yet, according  to this
definition, would not be considered blooms.

   Mention was made that temperature is the primary
reason for  the  seasonal  occurrence of blue-green
blooms and that blue-green  algae are not part of the
aquatic food  cycle because of their apparent in-
digestibility.

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             DETERMINATION OF  SAFE  LEVELS OF TOXICANTS AND OTHER

                       POLLUTANTS IN THE AQUATIC ENVIRONMENT
              L. L. Smith, Jr., D. F. Alderdice, F. J. Trembley, P. C. G. Isaac, R. C. Pendleton,
                                      and C. G. Wilder, Chairmen

                 APPARATUS FOR BIOASSAY OF WOOD FIBERS WITH FISH EGGS AND FRY

                                    Lloyd L. Smith and Robert Kramer *
   No satisfactory apparatus for bioassay of suspended
fibrous materials  originating in paper-mill wastes
was available for use with fish  eggs and young fish.
Equipment suitable for testing dissolved materials is
inadequate  for  suspended wood fibers  in varying
concentrations.   In order to determine  the effects
of  wood fibers on  eggs the material must be kept
in  suspension,  the eggs  must  be agitated, and  a
continuous water flow past the eggs must be maintained.
For use  with  young  fish, material must be kept in
suspension and  a  constant water  quality maintained.

    Fibrous  materials  in paper  mill  effluents  vary
from a few  microns to  5  millimeters in length and
their diameters vary  with the tree species and the
degree  of separation of  the wood.   The   physical
character  of the material varies with the  chemical
treatment to which  it  has  been subjected.   Wet wood
fibers are  slightly heavier than  water  but lighter
than  fish  eggs  usually  deposited on the bottom.

             TESTS WITH FISH EGGS

    Two types of  apparatus  were  used to   test the
influence  of  suspended fiber on  the survival  and
hatching of fish eggs, (1)  a  continuous-flow system
and (2) a closed system.

    Continuous-flow system.--A continuous-flow system
is  desirable for tests with fish  eggs  because it re-
moves  metabolites,  facilitates  egg  movement, and
permits maintenance of  constant water quality.   The
apparatus developed (Figs.  1 and 2) to achieve constant
conditions delivers a measured flow of a standardized
suspension of fiber to a mixing chamber where it is
diluted  to the desired concentration with fresh water
of  constant  temperature  and oxygen  content.   The
standard  stock  suspension  is  pumped  from   the
reservoir  to the  mixing chamber by a Sigmamotor
peristaltic-type pump driven through a speed changer
that permits accurate calibration of flow.  The pump
manipulates  Tygon plastic tubes which run from the
concentrated-fiber reservoir to the mixing chambers
without joints or constrictions. Tubes of four diameters
may be used simultaneously to provide four rates of
flow  to  each of four separated mixing chambers.
Two fibers at two levels or  one fiber at four levels can
be  supplied to  the test  chambers.   Liquid level
in the mixing chamber is maintained with a float valve
on  the water supply. Outflow from the mixing chamber
through the test chambers is regulated by raising or
lowering  the  level  of  the  overflows on  the  test
chambers.    The  flow  is adjusted to achieve the
 proper  action among  the  eggs and  a satisfactory
 suspension of fibers.   By adjusting the density of the
 fiber concentrate, speed of the pump, and rate of flow
 any desired level of  fiber load may be  circulated
 through the test  chambersi  Constant agitation in the
 concentrate  reservoirs  and mixing chambers is
 required.

    It has been practical  to operate the equipment up
 to  26  hours on a single  charging of the concentrate
 reservoirs, and  the apparatus has been continuously
 run for 20-day periods. Test chambers are standard
 1000-ml.,  3-necked,  distillation  flasks. This equip-
 ment  has  the  advantages of easy  sampling of eggs
 through the open overflows during the run and is free
 from  clogging in the metering pump.  Oxygen in the
 water can be maintained at predetermined levels by
 regulating the oxygen  content of water supply with
 nitrogen stripping columns or a mechanical degasser.

    Closed system.-—A closed system for tests of fiber
 with eggs  was made by attaching aspirating tubes to
 a distillation flask (Fig. 3).  Fiber and eggs were
 placed in the flask.  The fiber  suspension was then
 circulated at a  rate which gave adequate agitation
 to  the eggs.  In runs  exceeding 12 hours water and
                               WATER
                                      FLOAT V.
    MIXER
                  PUMP
              CONC.
              FIBER
                                        TEST
                                       CHAMBER
Figure 1.  Schematic drawing of continuous-flow system for sub-
        jecting fish eggs to constant wood fiber loads.
* Department of Entomology, Fisheries, and Wildlife University of Minnesota, St. Paul 1, Minnesota.

                                                  309

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310
DETERMINATION OF SAFE LEVELS OF TOXICANTS
                             Figure 2.  Continuous-flow apparatus for testing fiber loads on fish eggs.
    Figure 3.  Closed woter system for incubation of fish eggs in water with varying fiber loads.  Water and fiber rises through outside
             tubes to upper reservoir and descends through central tube.  Discharge of central tube at bottom agitates eggs.
                                                                                                                 GPO 8 16-361 — 1 1

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                     Apparatus for Bioassay of Wood Fibers with Fish Eggs and Fry
                                                311
                            Figure 4. Battery of closed-system vessels immersed in water bath.
fiber  were  replaced  every  12  hours.   Constant
temperature was maintained by immersing the battery
of units  in  a water bath (Fig. 4). Uniform water flow
in the different units was maintained by use of constant
air manifold pressure.   Flow induced  by aspirators
was varied by changing manifold pressure.

   This  system  has the  advantage of retaining fry
after  hatching and does not require continual prepa-
ration of large  batches of standardized fiber con-
centrate.   By adding nitrogen in proper proportion
to air constant, predetermined oxygen levels can be
maintained.

             TEST VESSELS FOR FISH

   A  closed-water system  employing  glass hatchery
jars  18  by 8 inches was found to be  satisfactory to
                      Figure 5. Closed-water system for subjecting small fish to various fiber suspensions.

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312
                           DETERMINATION OF SAFE LEVELS OF TOXICANTS
test  the effects  of fiber  suspensions on  fish up to
5 inches in length (Fig. 5).  Fish were placed in the
jars  with  the water  suspension of fibers.  A gentle
circulation of water was maintained  by use of  a
central  aspirator tube.   Rate  of circulation was
controlled by adjusting  the air pressure to the tube.
A  battery of 27  jars with varying treatments was
operated simultaneously from a common air manifold.
All jars  were  immersed  in  a water  bath (Fig. 6)
and  held at a predetermined temperature  in semi-
darkness.   Placing  the  apparatus in reduced  light
caused  the  fish to distribute  themselves throughout
the jars.  Tests were run for periods up to  96 hours.
Saturated oxygen levels were maintained but control
of oxygen could be achieved by mixing air  fed to the
aspirators  with appropriate  volumes  of  nitrogen.
                                Figure 6.  Battery of closed-system vessels for small fish.
                                THE DESIGN OF A NEW FISH RESPIROMETER

                                                J. JR. Brett *
                  INTRODUCTION

   Studies on  the respiratory metabolism of young
sockeye salmon have been conducted in a respirometer
designed to impose exact velocities and temperatures,
thereby  permitting measures  of the oxygen require-
ments for swimming at any speed up to and including
fatigue levels.  The  aim has  been to obtain precise,
reproducible data on  normal fish such that subsequent
tests involving abnormal conditions could be expected
to reveal the presence of  metabolic stress separate
from normal variability.  Since the metabolic rate is
dependent on or influenced by a  variety of environ-
mental factors including temperature, salinity, oxygen
availability, pH, and acclimation history,  as well as
such  characteristics as size, condition (exercise and
diet), excitation state (internal secretions),  diurnal
rhythms, starvation (post-absorbtive period), sex, and
age, it  was necessary to  pay close attention to each
variable and to design apparatus to meet the require-
ments.

                   APPARATUS

GENERAL CONSIDERATIONS
   The design provides for the recirculation of water
in a closed tunnel (containing the fish)  at any given
velocity, up to maximum output of the pump. New water
  Fisheries Research Board of Biological Station, Canada, Nanaimo, B C

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                                  The Design of a New Fish Respirometer
                                               313
can be introduced independently for samplingorflush-
ing, or a continuous flow of water can be steadily ex-
changed.

   The metabolic rate is determined by measuring the
change in oxygen content at regular intervals, followed
by flushing to maintain oxygen level, or by measuring
the difference in oxygen level between  incoming and
outgoing water of known flow rate.

   The fish is forced to swim against the current by
use of  a small electric charge (4 volts  AC) on a wire
screen.   The fish cannot  do less than the minimum
work to swim at the prescribed velocity, provided no
areas  of  reduced  velocity exist; it may do more by
being over-excited and swimming against the walls of
the chamber  or forward  screen.  Hence, repeated
values  must be obtained at each velocity, with atten-
tion being directed to the  minimum values which re-
present the non-excited levels.  By progessively in-
creasing  the velocity  in   1-hour  steps the relation
between swimming speed and metabolic  rate can be
established, with the extremes describing the basal and
active  levels.


PARTICULAR  FEATURES  (SEE ILLUSTRATIONS)


   Structure.  The drive unit including pump is sep-
arately mounted from the tunnel section and physically
linked  through rubber joints, reducing vibration trans-
fer.  The tunnel is of plastic tubing (2" PVC) with fiber-
glass expansion and contraction  cones leading to and
from the  plexiglas  fish chamber (4-1/2" ID x 12").
Freedom to swim is provided while reducing the total
volume of circulated water (4.5  gal ) to a minimum,
without undue frictional loss  and heat production.
   Drive Unit.   A 3-HP electric  motor top-mounted
on a Carter Variable Speed Gear drives a centrifugal
Worthington pump.  Maximum output is approximately
450  gal/min  against a  developed head of 70 feet.
   Velocity.  A consistent, flat velocity profile occurs
over  the entire range  of velocities (0-4 ft/sec)
through the fish chamber.  This is achieved by use of
appropriately designed cones and a series  of three,
spaced  turbulence  grids  preceding  the   chamber.
Velocity is continuously measured by a Pottermeter
bearingless,  turbine-type  flow meter calibrated  for
direct read-out for  the  rate through the  chamber.

   Temperature.  A  500-W heater counteracts over-
cooling from a refrigerated heat exchanger. The latter
is a stainless steel insulated cooling shell with glycol
refrigerant (down to -15°C) recirculated fromasepa-
rate cooling  unit.  Exchange water is thermally con-
trolled prior  to introduction.

   Oxygen. Exchange or flushing water is presaturated
to 105% of atmospheric  oxygen  and allowed to be
respired down  to 95% when the  unit is  on  closed
circuit.  A needle valve water sampler controls rate
of exchange during open  circuit.   Winkler  titrations
are employed but provision for an oxygen  electrode
is provided  at  the tee housing the pressure  gauge.
   Fish Chamber.   A forward and back, electrified
screen of piano  wire limits movement over  a 15-inch
length.  A black, forward cover-area is provided, and
a  contour-formed  access port.    Surrounding  the
chamber,  and faced with insertable one-way  glass, is
a light-box with  incandescent lumiline bulbs in series
with a variable transformer. Very low lighting is used
for  resting studies.  A black rubber mat contours  the
outside  bottom third  of the chamber to provide good
reference and "bottom-relation" for the fish.

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314
                           DETERMINATION OF SAFE LEVELS OF TOXICANTS ,
                                                 STAtNLESS    ,-  ----- '
                                                 STEEL PIPE, - ' 7. - ; ' ' '**—INSULATION
                                                                                              NEEDLE VALVE
                                                                                              WATER SAMPLER
                                  REFRIGERANT
                                                           FISH  RESPIROMETER
                                             REFERENCES

Mar, John. 1959. A proposed tunneldesignfor a fish     take and swimming speed in  young sockeye salmon.
respirometer.  Technical Memorandum 59-3, Pacific     Abstract, Amer. Zool., 2(3).
Naval Laboratory, Esuimalt, B. C.
                                                      Brett, J. R. 1963.  Some considerations in the study
                                                      of respiratory metabolism in fish, particularly salmon.
Brett,  J.  R.  1962.  The relation between oxygen up-     J. Fish. Res. Bd. Canada, 19(6).

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                 Apparatus Used for Studying Avoidance of Pollutants by Young Atlantic Salmon
                                               315
     APPARATUS USED FOR STUDYING AVOIDANCE OF POLLUTANTS BY YOUNG ATLANTIC SALMON

                                             John B. Sprague *
   The  essential  part (Fig.  1)  is a Plexiglas  tube
 134  cm  (53 inches) long  and 14.6 cm (5-3/4 inches)
 in diameter.   Into  each  end of  this tube peristaltic
 tubing-pumps  feed 2 liters of water per  minute via
 white plastic  funnels. The water is drained from the
 center  of the avoidance tube by four hoses leading to
 waste  via a  common chamber.  The tube is kept a
 little more  than half full,  and is partially open along
 the  top  for insertion  and removal of fish.  Baffle
 plates of Plexiglas  are installed 10 cm  (4 inches)
 from each end.  The other four lines which can be  seen
 around  the  tube  are merely  crayon marks  used to
 designate the position of the fish.

   A third variable-speed peristaltic pump can add the
 pollutant to either side by way of the funnels. In the
 photograph, dye has been pumped into the right  hand
 side.

   The  wooden doors close to shield the fish from
 visual disturbances.  Above the avoidance tube can be
 seen Plexiglas heating chambers,  gas  equilibration
 columns, and  constant-head  containers.  Underneath
 the table are stock-tanks of fish being acclimated.

   The apparatus gave a sharp junction between "pure"
 and  "polluted" waters.  Best results were obtained
 by measuring the time spent in each end of the  tube
 by actively swimming fish.


  Fisheries Research Board of Canada, St. Andrews, New Brunswick, Canada,
                      Figure 1.
                      AN APPARATUS FOR TESTING THE SWIMMING HABITS OF FISHES

                                             K. A, Pye'finch*
   Observations on the leaping  behavior  of  salmon
and  trout  were  carried  out  by  T.  A.  Stuart in a
channel 50  x 1.25 x 1.5  feet  made of transparent
perspex  1/4-inch thick.   The channel was  divided
into  two parts, the upper part 30 feet long and the
lower 20 feet. The  upper channel was mounted some 20
inches above the lower and connection between the two
parts was  provided by  a perspex fish  ladder.  The
long section of the  channel  could be  tilted  to below
the gradient by means of an hydraulic jack. Provision
was made for  the insertion of dams and spillways
of various  sizes  into  the  channels.   These dams
were also made  from  1/4-inch  perspex sheet and
rectangular, triangular, and trapezoidal openings were
cut into these dams.
 ' Department of Agriculture and Fisheries for Scotland Freshwater Fisheries Laboratory Pitlochry, Perthshire, Scotland.

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316
DETERMINATION OF SAFE LEVELS OF TOXICANTS
PHYSIOLOGICAL CONSIDERATIONS IN STUDIES OF THE ACTION OF POLLUTANTS ON AQUATIC ANIMALS

                                             Paul  0. Fromm *
   During the  past few years in our laboratory we
have investigated  the effect of hexavalent chromium
(as chromate) on aquatic animals. Most of the results
have been published and therefore it would seem re-
dundant  and superfluous to  discuss these data  in
detail again.  Rather, I would like to refer to these
studies  somewhat superficially while presenting my
views on the need for a greater emphasis on a physio-
logical  approach  in the study of some  problems of
water pollution.

   Physiology, as you know, is that branch of biology
that is  primarily concerned with  a  study of life
processes of  living organisms or, stated differently,
a  study  of  the functions of organs and parts during
life.  There have been many studies dealing with the
relationship between animals and  their  environment
and, indeed, the ecological distribution of some species
can be explained largely on the basis of the physiology
of  the animals involved.  In addition, physiologists
have also been concerned with the reactions of animals
to changes in their environment—studies of the physio-
logy of stress. "Stress," as used in this paper, may
be  defined  as the  conditions(s) resulting from any
environmental   change  that  disturbs  the  normal
functioning  of  an  animal  to such an extent that its
chances  for survival are  reduced.  The  pollution
biologist, with  a  physiological  approach  and using
fish as  an  assay animal, should be concerned  with
what  occurs on the surface and within the  fish in
response to a pollutant; whereas, the physical chemist
and limnologist should be  concerned more with the
physical and chemical  characteristics of the  water,
and events occurring in the immediate  environment of
the fish.

   At this  juncture three questions might properly
be asked: Why a physiological approach? Are present
and past methods of investigation no longer acceptable?
Is this just another "gimmick"  to be used  to obtain
large-grant  funds from  various  federal  and  state
agencies?   Answers to these questions may be gained
by  asking   still another  question:   Is  the study of
non-acutely lethal  concentrations of water pollutants
really necessary?  My answer to  the latter is an
unqualified yes!

   In studies of water pollution perhaps the most widely
used method for the evaluation of toxicity of materials
to  aquatic  animals  is  the fish  bioassay (TLW
determination) proposed some years ago (Doudoroff,
et al., 1951).  The mean tolerance limits serve only
as  useful indices  of the relative toxicity of the  sub-
stances  tested  and do not  represent concentrations
deemed  safe  or harmless.   In  a  somewhat similar
approach, Herbert (1961) in  England, has  presented
data  from  short-term toxicity  studies  using  a  log-
                            log plot of period of survival versus concentration.
                            A threshold of toxic  concentration is defined as that
                            concentration that would kill no more than 5 percent
                            of  fish as  susceptible as trout within 3 months. In
                            this as well as the fish bioassay procedure, the extra-
                            polation  of values obtained to  concentrations  that
                            are  supposedly   biologically   safe  is  somewhat
                            hazardous  to  say the least.   This is illustrated by
                            the effect of lead on fish.

                              In sufficiently high concentrations lead ions combine
                            with  mucus covering the  gills and  give the typical
                            protein coagulation reaction that results in interfer-
                            ence  with  the respiratory process.   As a  result
                            death is  rapid and is due  to  suffocation. Dawson
                            (1935)  has shown that after sufficient exposure (16
                            to  183 days)  to  very  low concentrations, lead can
                            act  internally  causing  significant  changes in the
                            blood (pronounced secondary anemia), liver (increase
                            in  macrophages  with progressive accumulation of
                            pigment  of erythrocytic origin), and spleen (decrease
                            in  erythropoietic activity and presence of increased
                            numbers  of pigment macrophages).  A TLm value for
                            lead,  determined  over a  period of not longer  than
                            96 hours, involves the use of acutely lethal and  non-
                            acutely lethal concentrations to provide data on which
                            the determination of a biologically  safe concentration
                            of  the metal  is  based.   The fact that the cause of
                            death may be  changed entirely when different  con-
                            centrations of  the metal are used is not taken into
                            account  in any way.   The question with respect to
                            short-term studies is, "How (if at all) are those fish
                            that  survive the test affected by the pollutant being
                            studied?"  The question is not answered by the fish
                            bioassay technique, nor was it intended to be. Answers
                            must be obtained from long-term (chronic) studies with
                            low concentrations of pollutants. This does not mean
                            to  imply that the  fish bioassay or other short-term
                            studies  have no value and should  therefore be  dis-
                            carded; the author f eels, however, that if realprogress
                            is  to  be  made  in  determining biologically safe  con-
                            centrations for various pollutants we must turn to
                            the assessment of the effects  on biological material
                            of  non-acutely lethal amounts of toxicants.    With
                            death ruled out as  an endpoint, we are thus forced
                            to  establish procedures for investigating alterations
                            of  functions in  living animals in response to environ-
                            mental stress (pollution).

                               In assessing the  response  of  aquatic animals to
                            pollution the  determination of one  or a number of
                            specific  changes  in the internal  state  of an animal
                            may   be  made.    Specific  changes  or differences
                            resulting from pollution  stress  may be decreased
                            liver  glycogen, hormonal  depletion,  elevated or de-
                            pressed  blood-sugar  levels,  accumulation of lactic
                            acid  in the blood, or other chemical  changes.  The
  Department of Physiology and Pharmacology, and Institute of Water Research, Michigan State University, East Lansing, Michigan.

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            Physiological Considerations in Studies of the Action of Pollutants on Aquatic Animals
                                              317
remark  by  Gertrude  Stein  to the  effect that  'a
difference, to be a difference, must make a difference'
is particularly pertinent to this discussion.  Changes
that may be useful  parameters in determining the
severity of pollutional stress  may  be  of  a  histo-
pathological nature such as necrotic changes in various
organs, cirrhosis of the liver, degenerative changes,
and many others.  Additional changes, which could be
partially included in  either of the  above categories,
are  blood-vascular changes  such as  alteration  of
hematocrit, hemoglobin, plasma proteins, or changes
in the amount and type of formed elements in the cir-
culating blood.

   Some of the suggested parameters have been used
in our laboratory. For example, it  was found (Schiff-
man and Fromm, 1959) that trout exposed to various
concentrations  of  hexavalent chromium responded by
showing  an increased hemoconcentration (increased
hematocrit).   This rise in hematocrit was accounted
for  by an increase  in cell  number,  cell  volume,
and a probable decrease  in plasma volume.   It was
suggested  at the  time that investigations should be
carried out to determine whether the  rise in hematocrit
could be used as an index of chronic toxicity. Resear ch
with largemouth bass (Fromm and Schiffman, 1958)
showed that  chromium caused severe pathological
changes in the gastrointestinal tract of exposed fish
that in all probability completely destroyed its diges-
tive function.  In  trout exposed to  1 ppm hexavalent
chromium  for  up to  38 days the blood-sugar  levels
were high (90 mg%) after 20 days and dropped to about
40 mg% after 38 days' exposure, whereas  the blood-
sugar  level  in  controls  ranged  from 40 to 60 mg%.
Lactic acid showed a  gradual  rise during the period
of  exposure;  however, no differences were  noted
between controls and chromium-exposed fish.  Liver
glycogen values were similar although quite variable
in control and  exposed fish with values ranging from
0.1 to  2.4  gm%.   Muscle glycogen  response was
similarly  variable and the values  were significantly
lower  than  those  for liver glycogen,  ranging from
0.01 to 0.37 gm%.   Tissue respiration  studies re-
vealed no differences  in the metabolism of slices of
liver,  kidney  and pyloric caeca tissues of fish ex-
posed to chromium when compared  to similar tissues
from  control fish.  There were differences between
types of tissues,  the average rate  of oxygen con-
sumption  (QO,) being 2.7, 2.0, and  1.6  microliters
per milligram  per hour for kidney, liver, and pyloric
caeca, respectively, measured at 13  to 15 °C.  These
data on the physiological responses of trout to exposure
to a 1 ppm concentration of chromium are preliminary
and few in number and have not heretofore been pub-
lished.  It can be seen in this attempt  to give an overall
clinical picture of the effect of chromium on fish that
many of the parameters investigated showed no signifi-
cant change in the  exposed fish.

   Various difficulties are encountered in collecting
data  reported  in the previous paragraph.    Three
graduate students and the author were simultaneously
involved in the collection of some  of these data.  In
most  cases one is confronted  with a notable lack of
good  control data  and must therefore  spend  con-
siderable time establishing normal  values. Even when
data are available one is usually amazed at the tremen-
dous range in the values reported as well as the number
of different journals  and assorted publications from
which  the  information must be gleaned.   This is
especially  true of reports  dealing with fish;  some
attempts have been made, however, to  survey the per-
tinent  literature in this  field (Hunn, 1960; Schwartz,
1961).  In addition to literary barriers and such factors
as variations in the nutritional status of experimental
animals, sex  differences, etc., more hindrances to
productive  research appear  such as the necessity of
drastically modifying methods originally designed for
use with larger animals. Several new microtechniques
(viz. microhematocrit method) have appeared in re cent
years, however, which should prove helpful in work with
smaller  vertebrates  and invertebrates  although the
methods devised have been primarily for clinicalpro-
cedures in  human medicine.

   Data of  the type under discussion are usually ob-
tained  from research carried out  in a laboratory or
possibly at a  fish hatchery.  In certain cases histo-
pathological information may be obtained from  ma-
terial  obtained from aquatic animals taken from pol-
luted waters.   In any event, highly trained personnel
are needed to  carry out the observations, which differ
quite drastically from those of the classical pollution
biologist that  have been in vogue for the past several
years. In addition to the initial, omnipresent need for
money, two things are necessary for research of this
type:  (1) favorable attitude of administrators, and (2)
trained personnel to do the work.

   A somewhat different approach to the assessment of
the effect of pollutants on aquatic animals has been
proposed (Brett, 1958), which embodies the concepts of
resting and active metabolism and scope of activity
as originally described by Fry (1947).  In this method
the resting  metabolism  (oxygen  consumption)  of
"normal" or control animals (fish were suggested as
assay  animals) is measured and then their maximal
rate of  oxygen consumption is determined by sub-
jecting the animals to some type of forced activity
(e.g.,  swimming against a current).   The difference
between the two rates of oxygen consumption is des-
ignated as  scope for  activity or  performance  capa-
city.   The experimental animals from the polluted
environment are tested similarly and any change in
performance capacity noted.  This procedure is based
on the assumption that no matter what environmental
stress is  placed  on an animal,  it will  be reflected
in a change (increase  or decrease) in normal metabo-
lic rates. In properly conducted experiments the effect
of a pollutant could be assessed by stating its effect
on either the  active or resting metabolism,.  An al-
ternative way of expressing the  results would  be to
indicate  the degree  of  change in the performance
capacity of the assay animals as the result of exposure
to a toxicant.  With the first approach one would be
faced initially with the need for setting up norms for
the metabolic levels associated with a variety of actions
and normal functions in the assay animals.  With re-
spect to a decrease in performance capacity one would
have to arrive at some  decision as to the magnitude
of change  that  must  occur before any toxic effect
could  be  considered  to be  acting  on the animals.
Despite  several  difficulties in this approach to the
study  of pollution, the method does have advantages.

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318
DETERMINATION OF SAFE LEVELS OF TOXICANTS
In general, less highly trained personnel are needed
to carry out research and probably  the overall ex-
penditure of funds for equipment would be lower than
that for the studies noted above.  A respirometer
similar to  that designed originally by Fry (1947) could
be used for fish studies and, since this apparatus would
not be extremely  cumbersome, it might be possible
to conduct  both laboratory experimentation and studies
in the field.  With the advent of dropping mercury and
polarographic oxygen electrodes, which could supple-
ment or supplant  the use of the dependable Winkler
procedure, measurement of the dissolved oxygen con-
tent of water should present no obstacle.

   If it would be impracticable to conduct as elaborate
an  experimental program as that outlined above, one
could resort to a method similar to that described
by Fromm  (1958) for the determination of the effect of
toxic materials on the general  metabolism of fish.
Also, with some aquatic and/or air-breathing macro-
invertebrates,  measurement  of  their oxygen con-
sumption could be carried out with the conventional
Warburg apparatus or a constant pressure respiro-
meter  such as  that designed  by Reineke  (1961).

   Both the specific physiological and the general me-
tabolic  approaches to the study  of pollution as dis-
cussed above have their advantages and disadvantages
with respect to the type of personnel needed, amount
and type of research equipment and facilities necessary
to  carry out this type of research, etc.   From the
standpoint  of comparative physiology and medicine rel-
atively  little would be gained from the "general me-
tabolic" approach; however, many benefits may accrue
from physiological studies.  For example,  Knoll and
Fromm  (1960)  reported that hexavalent chromium is
not concentrated in muscle tissue of fish to any signifi-
cant degree, hence human consumption of this portion
of  fish  taken  from  water  contaminated with  2.5
milligrams  of chromium per  liter or less would
probably represent  no serious  health hazard.  Dr.
R.  J.  Collins (Collins, Fromm,  and Collings,  1961)
has  presented  data obtained in  our laboratory  on
the excretion of chromium by the dog. This report
provides some  information as to the  way both tri-
and hexavalent chromium are excreted by a mammal
and is apparently  the only report dealing specifically
with  this  topic.   It  might be added that the use
of  isotopic  chromium  clinically is  becoming  more
and more widespread and any information concerning
the mode of excretion of this  material is desirable.
In addition, Dr. J. R. Hoffert (Doctoral thesis, Mich.
State Univ.,  1962) has made a thorough study of the
metabolism of  hexavalent chromium by the  nucleated
red  cells  of the  painted  turtle.  He  has developed
methods for tagging these cells  and has provided
procedures that can be utilized  in the study of blood
and  blood-vascular changes of lower vertebrates in
response to a stress (pollution) situation.

   If  it is  assumed  that pollution studies utilizing
a  physiological approach are  desirable,   we are
immediately faced with the problem of where and by
whom will  such studies be  carried out.  The author
is of the opinion that a great deal of encouragement
should come from the Environmental Health  Section
of the  U. S. Public Health Service.  This agency or
                           group  has jurisdiction  over large sums of federal
                           monies and,  if properly  informed, they should be
                           quite competent to stimulate and subsidize research
                           work of this type in various agencies and  organi-
                           zations.  Industry  should also bear its share of the
                           responsibility in pollution abatement.  Among other
                           things,  industry  could  contribute to  research  in
                           water  pollution by setting  up  additional industrial
                           laboratories, by subsidizing new and currently active
                           programs in universities and various state and federal
                           agencies,  and  by providing facilities to  aid pre-
                           and post-doctoral fellows in their research.

                              In some  states the  Department of Conservation
                           has highly trained personnel who could  carry out pro-
                           grams such as those suggested above.   Those depart-
                           ments not having  people in this  category should give
                           some serious thought to retraining individuals, making
                           it possible for  certain employees to return to school
                           to work on graduate degrees.  If this is not feasible
                           these  departments  should  consult  with  research
                           workers at various universities or possibly hire them
                           in an advisory  capacity  or as director of a summer
                           research program. Many college researchers would
                           probably  welcome the  opportunity to  work at state
                           fish hatcheries or act  in a  supervisory  capacity,
                           in some cases on a gratis basis.

                              Federal  laboratories such as  those operated by
                           the  U.  S. Fish and Wildlife Service and the Robert
                           A.  Taft Sanitary Engineering Center, as well as state
                           agencies  other than those noted above,  should  also
                           be involved in these research activities. Cooperation
                           between various agencies  is desirable. In Michigan,
                           for example, we have biologists associated with the
                           Institute for Fisheries Research (closely allied with
                           Univ. of Mich.), the state Water  Resources Commis-
                           sion, Institute of  Water Research (Michigan  State
                           Univ.), and the Michigan Department of Conservation,
                           all of whom cooperate in various research projects.
                           As long as all persons concerned remain dedicated to
                           the task of providing usable and adequate water sup-
                           plies for our present and future generations, coopera-
                           tion can be  achieved  even though some  competition
                           between the different agencies may exist.

                              It has not been the purpose of  this paper to provide
                           ready answers to the manifold problems encountered
                           in water pollution.  Rather, it  is a plea to broaden
                           our  experimental design for the study of water pollu-
                           tion; more specifically, a plea for instituting additional
                           research based on a concern  for the  physiologic
                           responses of aquatic organisms  to non-acutely lethal
                           concentrations of  pollutants. There is no suggestion
                           that proven,  fruitful  areas of research be  discon-
                           tinued,  but that still another aspect be added to the
                           entire study.   In  the "medical  assault" on  cancer,
                           for  example, many points  of attack are utilized -
                           surgery,  chemotherapy, radiation, hormonal treat-
                           ment,  virus  studies  —  all play  a very important
                           role and few people have concerned themselves with
                           worrying about which  approach is best.  In pollution
                           studies,  the  "assault"  should   likewise  be many-
                           pronged — studies of stream ecology involving benthic
                           macro-invertebrates and fish, measurement of diatom
                           or  periphyton populations  and  their   growth,  TLm
                           determinations, and, as suggested here, experiments

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            Physiological Considerations in Studies of the Action of Pollutants on Aquatic Animals
                                              319
utilizing physiological  and  Mstopathological  tech-
niques.    No single approach  will  provide all  the
answers but, taken as a whole, biological  research
can  and must provide data on which  estimates and
recommendations  for  water quality criteria  can be
based.
                                             REFERENCES
Brett,  J.R.  (1958)   Implications and  assessments
of environmental stress.   The investigation of Fish-
power problems.  H.R. MacMillan'Lectures in Fisher-
ies.   P.A.  Larkin,  Editor,  Univ. of Br. Columbia,
pp. 69-83.

Collins, R.J., P.O. Fromm, and W.D. Ceilings (1961)
Chromium excretion in the dog.  Am. J. Physiol.
201:  795-798.

Dawson, A.B. (1935)  The hemopoietic response in the
catfish Ameirus nebulosus to chronic lead poisoning.
Biol.  Bull. 68: 335-346.

Doudoroff, P., B.C.  Anderson, G.E.  Burdick,  P.S.
Galtsoff, W.B. Hart,  R. Patrick, E.R.  Strong, E.W.
Surber and W.M. Van horn (1951) Bio-assay methods
for the evaluation of acute toxicity of industrial wastes
to fish.  Sew. & Ind. Wastes 23:  1380-1397.

Fromm, P.O. (1958) A method for measuring the oxygen
consumption of fish.  Prog.  Fish-Cult. 20: 137-139.

Fromm, P.O. and R.H. Schiffman (1958) Toxic action
of hexavalent chromium on largemouth bass. J. Wildl.
Mgt. 22:  40-44.

Fry, F.E.J.  (1947)  Effects  of  the  environment on
animal activity.  Univ. Toronto Studies, Biol. Ser.,
No. 55; Pub. Ontario  Fish.  Res. Lab. No. 68, pp.
1-62.
Herbert, D.W.M. (1961) Freshwater fisheries and pol-
lution control.  Proc. Soc. for Water  Treatment and
Examination 10: 135-161.


Hoffert,  J.R.  (1962)   The  in vitro uptake of hexa-
valent  chromium  by  erythrocytes, liver  and  kidney
tissue of the turtle, Chyrsemyspicta. Doctoral Thesis,
Michigan State University.

Hunn, J.B.  (1960)   The  chemistry of fish blood, a
bibliography. Wildl. Dis. No. 7, 1 microcard.

Knoll, J. and P.O. Fromm  (1960)  Accumulation and
elimination of hexavalent Chromium in rainbow trout.
Physiol. Zool. 33:  1-8.

Reineke, E.P.  (1961) A new multiple-unit constant-
pressure microrespirometer.  J. Appl. Physiol. 16:
914-946.
Schiffman, R.H. and P.O. Fromm (1959) Chromium-
induced changes in the blood of rainbow trout, Salmo
gairdnerii.  Sew. & Ind. Wastes 31:  205-211.

Schwartz, F.J. (1961)  A bibliography: Effects of ex-
ternal forces on aquatic organisms.  Contribution No.
168, Chesapeake  Biological  Laboratory, Solomons,
Maryland.

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320
        DETERMINATION OF SAFE LEVELS OF TOXICANTS
            ANALYSIS OF EXPERIMENTAL MULTIVARIABLE ENVIRONMENTS RELATED TO THE

                                   PROBLEM OF AQUATIC POLLUTION

                                            D. F. Alderdice *
                 INTRODUCTION

   The influence of quantitative environmental vari-
ables on a true response 17 may be considered from
the relationship
                       = (xiu,
                                      Thus,  for a  set of three associated variables
                                   operating on the  response,  estimated by Yp , the
                                   function  may be approximated by
YP  = Vo
                                                               Vl
                                                        bx
                                                                             2x2  + b3x3 +
for the u*k combination of levels where the k associ-
ated variables  xj, X2, ... xjj are varied over u = 1 ...
N  combinations of levels   (Box and Wilson, 1951).

   If  the associated factors are  considered as  a
finite  set, the biological response of an animal to
a  pollutant  tested at  levels of the  factors of the
set may be written, for example,
                                   a polynomial of order  2  embodying the mean effect,
                                   main effects,  quadratic effects, and cross-products.
                                   Estimates of  the b's,  the regression  coefficients,
                                   would be obtained experimentally  from orthogonal
                                   designs where

                                                       b = 2xy/Ix2
     = f
                                 x2, x3 j
where Yp  = measured response to a fixed  concen-
tration of a pollutant.  jxj, X2, x3j  = a set of three
environmental variables, which will operate according
to their presence or levels  on Yp. Possible varia-
tions in the operation of the finite set may be stated
as
x2, xg|,
x2
                              x3,   x2, x3,
   Extension of factorial schemes to the  composite
designs of Box and Wilson (loc. cit.) and the methods
of Plackett (see Box and Wilson) for incorporating
additional  observations  into initial designs sequen-
tially, provide extremely useful versatility  in ex-
ploring the response surfaces that  may be defined
by the polynomial.


   Estimates of Yp  may be obtained by appropriate
substitution of levels of the  variables  in the fitted
polynomial.   However, a better appreciation of the
manner  in which the associated  variables  modify
Yp  may  be obtained  by examination  of the response
surfaces computed from the geometric equivalent of
the polynomial
where the absence  of  variables  in the set refers
to a  coded zero or  "standard" level, the empty set
j£[ being standardized with respect to all associated
variables.

   It follows that none of these response systems may
be identical in measured effect, that is,
                                                  Y  -
                                                   p
                                          n
                                          ps
                                                               + X33X3
                                   where Y  =  response  at  the center,  or  region of
                                           ^    stationary response of the geometric con-
                                                figuration
                                                              Kii
                                              = eigenvalues defining the rate at which
                                                Yp changes in moving away from   the
                                                center in the direction of Xi
In other words the response to a fixed concentration
of a  pollutant may vary  according to the combina-
tions  of  levels of associated variables impressed on
the response system.
                                              = canonical form of the original variables,
                                                the transformation translocating and ro-
                                                tating the x-coordinates of the experi-
                                                mental design to correspond with the X-
                                                axes of the response configuration.
  Fisheries Research Board of Canada, Biological Station, Nanaimo, B.C.

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                            Analysis of Experimental Multivariable Environments
                                                                                                   321
                    RESULTS

   Studies of this  nature have been carried out ex-
perimentally with juvenile coho salmon (Oncorhynchus
kisutch).  An  example of the use  of these methods
was  made with reference to cultured pre-smolt coho
tested  from mid-January to  mid-February  1962,
averaging 7.35-centimeter fork length and 4.31 grams
in weight,  at  a time approximately 2 months prior
to normal seaward migration.

   Tests were  conducted on samples of 10 fish per
trial at 3 milligrams per liter of sodiumpentachloro-
phenate over  levels of salinity  (°/oo), temperature
(°C), and dissolved oxygen (mg/1) in  a 15-trial
composite factorial  design.   Response to each  of
the trial conditions was measured  as median resis-
tance time in  minutes.  A further  eight trials were
performed  for improved definition of  the principal
axes of the  resulting response surfaces.  Levels of
salinity, temperature, and dissolved oxygen are coded
in the following manner:
      Factor            Levels

X! Salinity, %oS     1   5.5  10

x2 Temperature, °C  2   4.5  7

x« Dissolved oxygen,  3.5  5.5  7.5
   mg/liter

where
 _ factor level - base level;
1            unit
                                Base level  Unit

                                   5.5      4.5

                                   4.5      2.5

                                   5.5      2.0
S - 5.5

 4.5
                                          _  1 n ..
                                             i;u)i
The responses obtained over two replicates (Trials
1  through  15) and additional trials (16 through 23)
are listed in Table 1.
                                                     Table 1.   COMPOSITE FACTORIAL DESIGN FOR 3
                                                               FACTORS EACH AT 2 LEVELS, INCLUD-
                                                               ING TRIALS AT THE CENTER AND ON
                                                               THE AXES OF THE FACTOR SPACE AT
                                                               11.215 UNITS FROM THE CENTER
                                                               (TRIALS 1-15). TRIALS 16 THROUGH 23
                                                               WERE PERFORMED IN SUPPORT OF
                                                               INITIAL FINDINGS.
Trial

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
Associate
xl
-1
-1
-1
-1
1
1
1
1
0
1.215
-1.215
0
0
0
0
1.215
1
1
1
2
1
1
0.340
factor
X2
-1
-1
1
1
-1
-1
1
1
0
0
0
1.215
-1.215
0
0
-1
-1.215
-1
0
-1
-1.400
0.600
0.200
levels*
X3
-1
1
-1
1
-1
1
-1
1
0
0
0
0
0
1.215
-1.215
1
1
1.215
1
1
1
0.380
0.125
Average response
time, minutes
Y
83
89
62
71
92
114
93
99
100
107
108
88
98
98
98
111
113
100
100
104
68
72
138
                                                       * xj — Salinity,
                                                                 X3 -
                                                                     %>o.       X2 — Temperature,
                                                                     Dissolved oxygen, mg/liter.
                                                     A point of stationary response iscomputedatthelocus
    Calculation of regression  coefficients from the
 trials of Table  1 provides the following estimated,
 with their standard errors
                                                       x,   =  0.8890     x0   = -0.2421      x, = 0.2117
                                                        Is                 2s                  3s
 bQ = 111.1478 ± 7.97

 bj = 6.9025 ± 4.42

 b2 = -7.0395 ± 4.51

 b3 = 2.4953 ± 4.49

 bn = -3.8914 ± 4.86

 Therefore
                            b22 = "14-5269 ± 6-72

                            b33 = -7.3060 ± 6.81

                            b12 = 0.4918 ± 5.02

                            b13 = 0.1298 ± 4.69

                            b   = -2.0013 ± 5.17
 Y  = 111.1478 + 6.9025XJ - 7.0395x  + 2.4953xg -

 3.8914XJ2  -  14.5269x22  -7.3060x32 +  0.4918x^2
  0.1298x^3 - 2.0013x2x3
                                                     equivalent to
                   9.50%o S
3.89°C
5.92 mg02/liter
                   The response at this point is calculated as 115.3324
                   minutes.  The polynomial can be reduced to canonical
                   form
                                                     Y  - 115.3324 = -3.8852X 2 - 14.6689X2 -7.1702X,2
                                                       P                     1           Z           o
                                                      The signs of the components on the right-hand side
                                                      of the equation  indicate that the response decreases
                                                      in moving away from the point of stationary response
                                                      in the direction of the X-axes.  The stationary point
                                                      is  concluded  to be a point-maximum or optimum.

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322
                               DETERMINATION OF SAFE LEVELS OF TOXICANTS
The response  surfaces,  accordingly,  are ellipsoidal
and are  illustrated in Figure 1 as  constructed from
the  canonical  equation.   Five  sections were  taken
through the ellipsoid in  the plane  of  Xj  and Xg at
X« = ± 1.204, ± 1 and 0.  With combinations of levels
of salinity, temperature,  and dissolved oxygen limited
to those that provide 87 percent (100 minutes) or more
of the optimum response  (found at the  center, S, of the
ellipsoid where X  = x,  = X3 = 0),  Planes  were con-
                                      structed in Figure 2 with the 87 percent response loci
                                      as the axial boundaries of each plane or ellipse. Com-
                                      binations of salinity, temperature, and dissolved oxygen
                                      levels selected on these planes (Xj = ± 1.204 are point
                                      limits  in the direction of Xg at Xj = X2 = 0),  which
                                      provides  at least 87  percent of  maximum resistance
                                      time to  3 milligrams of sodium pentachlorophenate per
                                      liter, may  be approximated from the calculated  re-
                                      lationships in Figure 3.
                                                                                     13.55
Figure 1. Response surfaces in  terms of median resistance time
         in minutes  for coho  salmon juveniles exposed to a
         3-mg/l  concentration  of sodium pentachlorophenate at
         various levels  of salinity  (X]),  temperature (X2),  and
         dissolved oxygen (X3),  The configuration is ellipsoidal
         and is  shown sectioned through the Xjand X2 oxes at
         Xj = 0. The X-axes refer to the response configuration;
         the x-axes,  with center 0, are those of the factor space
         investigated and  X =  f(x).  Three envelopes are il-
         lustrated  around the locus  of maximum resistance at S,
         enclosing loci equal to or  greater than 100, 80, and 60
         minutes median resistance time,  respectively.    The
         optimal  value at S is calculated as  115.33  minutes.
                                      Figure 2. Boundary conditions for the 100-minute median  resis-
                                               tance time envelope (Fig.  1) providing loci equivalent
                                               to 87 percent of the response at S.  The figure is con-
                                               structed by taking 3 planes through  the  Xj-axis of
                                               Fig.  1 at X3 = -]  and  0,  calculating corresponding
                                               values of Xj  and  X2  at  which  the  response is  100
                                               minutes,  and  transforming the X  values to original
                                               units.  Each triplet of figures indicates: upper-S°/oo,
                                               middle-°C,  lower 02, mg/l.
                \LJ_Ji
      Temp.,°C.  4.0 3.9
                02, mg/l

Three planes on the canonical
 axes of the response figure
  with  loci  transformed to
    original units.
    a  Xo = -1
    b  X3= 0
    c  X? = 1
                                                     >; 12
                                                         1   2\ 3  4  5  6
                                                    Temp., °C. 6.16.05.95.85.7
                                                                  0,, mg/l
                                    '                                                123 \4  5
                                                                                  Temp.,°C. 8.07.97.8
                                                                                         02, mg/l
        Figure 3. Combinations of salinity, temperature, and dissolved oxygen which at 3 milligrams of sodium pentachlorophenate
                per liter are calculated to provide 87 percent or greater of the response at S on the planes at which X3 z ±1 and 0.
                The axial limits at which X3= ±1.204, X] = X2 = 0 are not shown (9.43%>oS; 3.49°C; 02 3 54  mg/|- 9 57°/ooS-
                4.30°C; 02, 8.31 mg/l of Fig. 2).

-------
                            Analysis of Experimental Multivariable Environments
                                                                                                       323
                    DISCUSSION

   Considerable research effort within the past several
decades has been applied to describing functional capa-
cities among fishes.   Studies of metabolic rates,
primarily through measurements of oxygen consump-
tion,  have  more  clearly shown the manner  in which
changes in the aquatic medium  may influence  the
internal state of the animal and associated dependent
activities.  Homeostasis mechanisms have been recog-
nized  in poikilotherms as providing  a measure of
independence from the state of the external medium in
allowing the continuation of vital activities. Although
individual  contributions to knowledge of functional
capacities  are numerous, the most  recent  critical
evaluations and compilations  of Fry (1947), Prosser
(1955, 1958), Bullock (1955),  Wanberg (1956), Brown
(1957), and Prosser and Brown (1961) must be men-
tioned.

   Concomitant with the measurement of capacities
has  been  consideration of the underlying  question
regarding  their  ecological   significance,  not only
with reference to survival of the individual, but also
with  respect to  maintenance of  the species.  For
example, while the lethal  temperatures forming  the
boundaries  of  the  zone  of  temperature tolerance
(Fry,  loc.  cit.), may be defined with precision, they
bear  only  a gross relationship to habitat and geo-
graphical distribution.   The  ecological significance
of temperature preferenda is also unclear. Tempera-
tures permitting optimum scope for activity, however,
appear to have ecological significance (Brett, 1956).

   In  spite of the major  accomplishments in  the
description of functional capacities among fishes, there
remain large gaps in our knowledge.  This  is because
the biologist, faced with the practical field problem,
is still unable  to predict with accuracy or certainty
the results of many changes in the environment where
none of these is  obviously acute.  It is not the inten-
tion here to subject existing  estimates of functional
capacities  to  critical  scrutiny,   although Winberg
(loc. cit.) clearly indicates that such scrutiny is justi-
fied in some areas.  Rather, it appears a bridge of
understanding is  needed between functional capacity
and the evaluation  of the significance of these capa-
cities to meet environmental change.
   A  partial  key to the more critical evaluation of
capacities  is  suggested to lie in  their examination
within a framework of  physical and chemical factors
more  closely approaching  those of the normal and
inescapably complex environment.   The constrained
experimental conditions under which  capacities are
usually evaluated  present  a  highly simplified and
hence a typical environment compared with the varying
circumstances to which the animal may be subjected
naturally.  Moreover, homeostasis mechanisms may
only partially compensate for variations in the external
medium, resulting in more stressful or less stressful
areas  within the  zone  of  tolerance.  Furthermore,
if several or more factors vary, with normally viable
limits for  each factor,  an associated response may
reflect variations in viability or  capacity diverging
from  levels that would  be expected by single-factor
estimation.  The fact that interactions in biological
systems are  the rule rather than the exception would
support this argument.  Evidence of such interaction
is widespread in the  literature  (e.g.  Downing and
Merkens, 1957; Alabaster, Herbert and Hemens, 1957;
Lloyd, 1961).


   Related to the problem of investigating the complex
environmental situation is the consideration of ex-
perimental design.    Simultaneous  examination  of
several  or  more variables  quickly increases the
complexity of investigative procedure.  Efforts have
been  made to reduce the complexity of experimental
procedures by instituting standard methods with refer-
ence  to such  variables as  experimental water, age,
size,  species, temperature, and oxygen concentration.
If one is strictly concerned with the pharmacological
definition of comparative toxicity, such measures are
well founded.  If the end result of experimentation,
however,  is the assessment of probable  effect  of
environmental change or adulteration on associated
fishes,  the requirements  for definition will not be
standard but  will be concerned with the character-
istics of  the species  and  of the water it inhabits.

   The  system under examination becomes one not of
single variables but of multiple variables in which
functional capacities may be expressedinthe environ-
mental  situation  by  the association or interaction of
a  number  of factors,  all  in some manner defining
the absolute  level of effect.  Functional capacities
then delimit the ranges  of variables of known concern,
and their  action  as associates  will determine the
response to the total complex.


   Hence, in the example presented, of primary inter-
est is the fact that the response of the test fish to the
toxicant varied according to the levels of the several
variables simultaneously  impressed on the test fish.
Furthermore, the existence in this case of a particular
combination of levels of the three associated factors
that provides maximum or optimum resistance also
provides a means of qualitative  assessment of the
various levels of associated factors that may influence
the response to the toxicant.  Around the  response
center,  computed  at  9.50°/ooS,  3.89°C,  and 5.92
milligrams of  oxygen per liter  for pentachloro-
phenate, extend envelopes of equal levels of response
provided by alternate combinations of levels of the
three  factors considered.  Those enclosing the ellip-
soid   providing 87 percent of the  optimum  response
or greater  range from approximately 2  to 17°/ooS,
2  to  6°C,   and  3.5  to 8.5 milligrams of oxygen per
liter.


   The  response  surfaces  were constructed on the
basis  of acute biological assays. One reasonably might
question whether or not  the same relationships would
hold  at  lower concentrations of the pentachlorophen-
ate.   Although corresponding response surfaces have
not been evaluated at other lower levels of the toxicant,
the response to combinations of salinity,temperature,
and dissolved oxygen has been determined on linear
pathways cutting through the response surf aces (Alder-
dice,  unpubl.).  In these cases the same pattern of
response has been  obtained  at  other pentachloro-
phenate concentrations.

-------
324
DETERMINATION OF SAFE LEVELS OF TOXICANTS
   It is not suggested that all potentially poilutional
materials would yield response surfaces similar to
those developed  in  the  example.   The  manner in
which the animal responds to associated environmental
variables may very likely be determined by the influ-
ence of the particular pollutant on functional abilities
associated with the response.
   A further complication found in the study of juvenile
coho salmon is that  the response to the three asso-
ciated  variables  tested  is  not  constant  with age.
The locus of the optimum of the response configuration
changes  with age in the test fish (Alderdice, unpubl.).

   Discussion of the significance of the results obtained
requires consideration of the errors involved in their
estimation.   The methods of analysis employed were
proposed by Box and Associates for problems in which
experimental error is small.  Adequacy of fit of the
data to  a polynomial is  then judged by a comparison
of the residual mean square, after fitting of the con-
stants  in  the  polynomial,  with  the  experimental
error variance.   In the case  presented here, the
polynomial is a  good representation of the data in
the factor  space  investigated, although the experi-
mental error variance is greater than is theoretically
desirable.    It follows that the response  surfaces
constructed and loci estimated on these surfaces should
be considered as best estimates based on the existing
data.
   The interaction terms of the polynomial would be
zero only if  the axes of the factor space investigated
and computed response surfaces were coplanar.  Al-
though the  calculated interaction terms are smaller
than their standard  errors,  there is  no  reason to
suggest  that  these  estimates  are, in fact,  zero.
The  calculated quantities are, therefore, retained as
the best estimates  available from the data.   The
terms indicate factor dependence, biologically not un-
expected. Although the degree of dependence  in the
example (Figure 2)  suggests the interaction effects
could be ignored  in  related studies on other ages of
juvenile  coho, a  high level of biological significance
can be attached to the dependence between the factors
studied.
                        Q
   When compared with 3° factorial designs, the com-
posite design employed provides estimates up to second
order in half the number of experimental trials, with
some loss of sensitivity in provision of  the estimates.
In this study it was necessary to work in the shortest
practicable experimental intervals, as the test animals
were known to show appreciable changes in response
with growth.  With the availability of computer ser-
vices,  the  extension of  the designs and methods of
analysis  employed to  more extensive factorial arrays
should be possible, with little increase in computational
difficulty.

   A one-factor-at-a-time approach to the study of the
effects  of the three  variables employed would have
the best  opportunity  to succeed only where  there is
no factor dependence. Otherwise, an estimate of the
locus of optimum response would probably be obtained,
in this case on a salinity ridge below the center, after
a considerable number of experimental  trials.  In this
respect,  the  methods are an effective means not only
of describing the response surface in the factor space
                           investigated, but also for indicating the direction to
                           proceed toward higher response levels.

                              Although there are errors involved in the estimation
                           of the response surfaces, these errors are not unique
                           to the methods employed.  Since the environment may
                           act  as  a  complex,  interpretation of the manner in
                           which the response  may be altered by the complex
                           should conceivably be investigated by methods that con-
                           sider the association and interaction of the  various
                           factors forming  the  complex.   This is considered a
                           fundamental argument for the use of the methods em-
                           ployed.

                              The  response  configuration, once derived, provides
                           considerable insight into the manner in which many
                           possible combinations of the associated variables may
                           influence the  response.   One is led to question the
                           validity of biological assay data developed under con-
                           strained experimental levels of associated environ-
                           mental  variables, when such data are used to interpret
                           the  significance  of related poilutional changes in the
                           aquatic environment. If physical and chemical char-
                           acteristics of  waters vary seasonally or geographi-
                           cally, such variations may have a marked effect on
                           resistance patterns of associated fish populations ex-
                           posed to  even a  constant poilutional load.  The com-
                           bination of levels  of associated variables providing
                           optimum  resistance and the manner in which their
                           variation affects the response to particular effluents
                           or water-borne  contaminants may help define con-
                           ditions, locations, or times in which contamination is
                           associated  with  high or  low potential stress among
                           resident fishes.

                              If the  natural limits  of variation in the levels of
                           associated environmental variables are known or may
                           be estimated  for a  particular field situation, those
                           providing the lowest survival potential, as  calculated
                           from the response configuration, should be used as
                           background levels  when attempting any experimental
                           determination  of "safe levels" of concentration for a
                           pollutant  for which the response surfaces have been
                           estimated.  Although the estimation of "safe levels"
                           is  another problem entirely, its relationship with
                           associated factor levels is unmistakable.  The ability
                           of the experimenter to consider the problem of toxicity
                           simultaneously with associated physical and chemical
                           properties of the water that may influence  such esti-
                           mates  is regarded as  being  of first  importance.

                              From the point of view of preventing or minimizing
                           a potential poilutional problem, the relationship be-
                           tween associated environmental factors and their effect
                           on the response to a pollutant may initially define the
                           most likely locations in  which such a problem would
                           be minimized with respect to certain water  quality
                           alterations.

                              The  existence in a  response  configuration of a
                           point or area  of maximum resistance to a particular
                           pollutant  in terms of normally tolerated levels of
                           environmental variables  provides for a definition of
                           qualitative changes in water in terms of the resistance
                           of  selected resident species.   Water quality as  a
                           function of biological response might then be monitored
                           with reference to the contaminant defining the problem.

-------
                            Analysis of Experimental Multivariable Environments
                                               325
Remedial measures  could  be taken with regard  to
pollutional load when alteration in levels of associated
variables indicates a deterioration in response to a
locus on the response surfaces outside of an envelope
such as that defining combinations of water character-
istics providing 90 percent of the optimum response.

   Where the level of an associated variable, such as
dissolved oxygen concentration, varies outside of nor-
mally tolerated levels, the considerations dealt with
still apply.   The  problem becomes a special case
only in  that the factor in question exerts  more in-
fluence on the  multivariable  system  than  when  it
operates within tolerated levels, and under these cir-
cumstances may limit responses at all combinations
of levels of the other factors in the complex.


   To summarize these arguments consider, for exam-
ple, the problem of deciding on the best location for a
proposed industrial development with respect to its
water-borne  wastes.   The suggested steps toward a
decision are as follows:  1. Select one or more eco-
nomically important species of fish and determine their
response surfaces for the contaminant in  question,
with reference to environmental variables considered
to be of importance. 2. Define the  90 percent response
boundaries.  3. On the basis of these findings decide
on the location best satisfying the biological require-
ments.   4.  At this location obtain the known or esti-
mated range in variation of associated physical and
chemical characteristics of the water and choose the
set providing the  lowest response level within the 90
percent  response boundary.  5.  With the levels of
this  set as  background levels, determine the con-
centration-response relationship for the contaminant
in question and provide a limiting concentration with
a  statistically defined  "cushion" (e.g.x,,-4Xof Gad-
dum,  1956).  6. Monitor the actual situation  chemically
and biologically, as illustrated, against the probability
of changes' in water  quality exceeding the defined
limits of variation.

   With  reference to such  questions as "How  much
oxygen  does a fish need ?" or  "What  is the highest
concentration of a particular pollutant that may be
tolerated?",  it appears that the answers are relative
ones—relative to  the other factors and their levels,
which may be impressed simultaneously on the parti-
cular animal considered. It is suggested that the argu-
ments presented may assist in a better comprehension
of the significance of functional  capacities in meeting
environmental  change,  particularly  when considered
with reference to changes in water quality found in
the polluted environment.
                                             BIBLIOGRAPHY
Alabaster, J. S., D. W. M. Herbert  and J. Hemens.
1957.  The survival of rainbow trout (Salmo gaird-
nerii Richardson)  and perch  (Perca fluviatilis  L.)
at various  concentrations of  dissolved  oxygen and
carbon  dioxide.   Ann. Appl.  Biol.,  45(1): 177-188.

Alderdice, D. F. MS, 1962. Fisheries Research Board
of Canada, Biological Station, Nanaimo, B. C. (Unpubl.)

Box, G. E. P., and K. B. Wilson. 1951.  On the ex-
perimental attainment of optimum conditions.   J. R.
Stat. Soc., Ser. B, 13(1): 1-45.

Brett,  J.  R.   1956. Some principles on the thermal
requirements of fishes. Quart. Rev. Biol., 31(2): 75-87.

Brown, M. E., ed.  1957.  The physiology of fishes.
Vol. I, n.  Academic Press, Inc., New York.

Bullock, T. H. 1955.  Compensation for temperature
in the metabolism and  activity of poikilotherms. Biol.
Rev., 30(3): 311-342.

Downing,  K.  M.,  and J. C. Merkens.  1957.  The in-
fluence of temperature on the  survival of several
species of fish in low tensions of dissolved oxygen.
Ann. Appl. Biol., 45(2): 261-267.
Fry, F. E.  J.   1947.  Effects of the environment on
animal activity.  Univ. Toronto  Stud. Biol. 54,  Publ.
Ont. Fish. Res. Lab., No. 67, 62 pp.

Gaddum, J. H.  1956. The estimation of the safe dose.
Brit. J. Pharmacol., 11(2): 156-160.

Lloyd, R.  1961.  Effect of dissolved oxygen concen-
tration on the toxicity of several poisons to rainbow
trout  (Salmo gairdnerii Richardson).  J. Exp. Biol.,
38(2): 447-455.

Prosser,  C. L.   1955.  Physiological variation in
animals. Biol. Rev., 30(3): 229-262.

Prosser, C.  L., ed.  1958.  Physiological adaptation.
Lord Baltimore Press, Baltimore. 185 pp.

Prosser, C. L., and  F. A. Brown. 1961. Comparative
animal physiology.  2nd ed, W. B. Saunders Co., Phila.
ix + 688 pp.

Winberg, G.  G.  1960.   Rate of metabolism and food
requirements of fishes. (Published in Nauchnye Trudy
Belorusskovo Gosudarstvennovo  Universiteta imeni
V. I.  Lenina, Minsk, 253 pp., 1956).   Fish. Res. Bd.
Canad Trans. Series No.  194.

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326
DETERMINATION OF SAFE LEVELS OF TOXICANTS
                 THE BIOLOGY OF WATER TOXICANTS IN SUBLETHAL CONCENTRATIONS*

                                           Charles G. Wilder t
                  INTRODUCTION

   The problem of evaluating the significance of water
pollutants is at times discouragingly complex.  The
uses of water are so varied as to demand a bewilder-
ing number  of viewpoints in pollution assessments.

   In  the past, most studies have involved the killing
effects  of  pollutants on selected living organisms.
Useful  information has been  derived  from such
studies.    The  evaluation  of  a water  toxicant  in
terms of  kill  or  no-kill,  however, is somewhat
circumscribed  in effectiveness.  Many delicate re-
sponses of organisms are  never  observed.   All  too
often  crude data,  based on 50 percent kill or on time
to kill  50 percent  of  the  test animals, are used to
arrive at rather broad conclusions.

   With the advent of  a wide spectrum of pollutants
that  are poured into waters from many sources, it
seems essential that a  more sophisticated approach
be made to the problem of toxicants in  water. The
need for studying sublethal concentrations of toxicants
for the entire lifetime of the test organism has been
clearly emphasized.  1   The disrupting effects  of
minute  concentrations  of certain toxicants in water
on the normal  embryological processes  suggest that
studies involving  several  generations  of  the test
organism should be carried out. 2, 3

   In  this paper I propose to discuss critically  the
relationship  between  a toxicant  and  its biological
effects  and  to  suggest a theoretical  model for  the
assessment of water toxicants in sublethal concentra-
tions.

ALL-OR-NONE  RESPONSES

   In  the  evaluation of the  relationship between a
toxicant  and  the  physiological  effect it produces,
two factors or variables must be considered:
      1. Concentration of the agent,
     2. time of exposure.

   The latter variable is suprisingly often neglected;
all too frequently  it is considered for only relatively
brief  periods.   In addition, the physiological effect
to be produced  and recorded is usually  death.  The
measure of the  effect is ordinarily the time required
to kill  one half of the  experimental  animals or  the
dose  to kill one  half  of the experimental animals'
in a specified time.

   In  either  event, one  is faced with an all-or-none
response. The  biological significance of the animals'
not dying  is  ignored; their  value to the elucidation of
                            mechanisms  of  action  of  toxicants  is  minimized.
                            Similarly,  one  is left  uninformed concerning  the
                            biological  significance  of  the  animals  that  died.

                               The following general equation is useful to express
                            the relationship of dose to time: 4
                                       Ct = K+at
                                                   b + 1
(1)
                            where   C  is  the  concentration  of  the  toxicant  in
                            appropriate units; t, the time of exposure; K, a constant
                            related   to  species  susceptibility;  a,  a  constant
                            related  to the magnitude of rate of detoxication; and
                            b, a constant related to change in rate of detoxication.
                            It  is  evident  that if  the  constants K, a, and b are
                            known, the  relation between dosage (Ct)  and time  (t)
                            to  produce  a specified  physiological effect  may  be
                            determined.

                               A graphical method of analysis makes estimation
                            of  the  various constants relatively easy.  Equation
                            (1) is rearranged as follows:
                                      Ct  -  K  =  a t
                                                       b  + 1
(2)
                            If logarithms of both sides are taken, a straight line
                            is  invariably  obtained  when log  (Ct -  K) is plotted
                            against  log t;  the  slope of  the  resulting line will be
                            (b  +  1); log a  is equal to  the intercept on the log
                            (Ct  - K) axis  when t = 1.  If log-log paper is used to
                            plot  these  values, all  terms may be  read directly
                            from the chart without  conversion to  logarithms.

                              K is ascertained by plotting Ct against t on regular
                            coordinate  paper.   If  K is  difficult to locate (it is
                            the  intercept on the Ct axis when t is zero), because
                            of  the curvature  of the resulting line, a plot of log
                            (Ct  - K) against  log  t, which gives the straightest
                            line, will approximate K adequately.

                              The  importance of  the time factor in evaluating
                            possible  toxicant hazard is worth repeated emphasis.
                            Legal considerations make it  important  for water
                            pollution experts  to have  a clear grasp of the real
                            role of  time in  modifying  toxicological responses. 5

                              If  equation (1)  is used  to evaluate the  biological
                            effects  of a  compound suggested as a possible oil
                            spill eradicator, some interesting results follow.  The
                            data are taken  from  published literature. 6   The
                            numerical results from Chadwick 6 were rearranged
                            to permit the calculation of the toxicant in milligrams
                            per  liter.  Time in minutes is given and Ct was cal-
                            culated  in terms of milligrams per minute per  liter.
                            When time was plotted against Ct, K  was found to
                            be  2,300.  (Ct - K) was calculated and plotted against
* Preparation of this report was supported in part by a contract, DA-49-193-MD-2216, between Kent State University and the
  Surgeon-General, U.S. Army.
")" Kent State University, Kent, Ohio

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                        The Biology of Water Toxicants in Sublethal Concentrations
                                               327
time  in  minutes on  log-log paper.  The constant a
was found to be approximately 37, which would suggest
that  the  eradicator is not detoxified  to any great
extent.   Table  1 gives the selected calculated data
in tabular form. The physiological effect tested was
death of all fish.
Table 1. BIOLOGICAL EFFECTS OF OIL SPILL
         ERADICATOR ON STRIPED BASS6
Concentration
of agent,
ing/liter
50
16
10

Lethal time,
minutes C
60
300
600

;, mg/min/liter
3,000
4,800
6,000

Ct - Ka
700
2,500
3,700
aK = 2,300; a = 37.
   It is necessary to point out that formulas involving
the Ct  = K relationship quickly lead to  absurdities
if  taken seriously over wide  ranges  of values.  7
This kind of formula asserts that an infinitely small
concentration  of  a drug  will produce  a  specified
action  in infinite time and that an adequately large
concentration  will  produce  an instantaneous effect.
Over very small ranges of concentration or time, the
product  Ct may be constant.    Extrapolation is of
questionable validity. The  older literature on the sub-
ject  is reviewed by Clark. ?  The straight- line re-
lationship  resulting from the  use of  the  Ct  = K
formula  is useful, but this analysis must be used
prudently to avoid misinformation and error.

               THE LD5Q  CONCEPT

   If one is studying the toxicity of some compound
to a test animal, the LDso value is often used. The
LD50 is  the amount of toxicant in the test animals
that  kills  50  percent  of those tested in a. specified
time.   In tests  of this kind, the toxicant is  usually
injected into the animals.
   The  danger and  irrationality  of using the
concept for animals respiring in  an aquatic medium
should be  obvious;  the  pitfalls are illustrated in a
recent paper 8 in which the attempt is made to express
the toxicity  of   1-naphthyl   N-methylcarbonate  to
goldfish in terms of the
   You will recall that the LDso denotes the actual
amount of toxic material that gets into the test animal.
In the paper  referred to, 8 the term LD5Q is used
to apply  to  the  concentration of toxicant  in the
surrounding water.  Such  usage is meaningless — but
worse, the data may  be taken  seriously by others.


   It is obvious that if a toxicant is added to the air
a man is breathing, the concentration of the agent and
the time during which the subject breathes the poisoned
atmosphere are both essential if one is to conclude
anything   about  the  biological action of the agent.
   Similarly,  as was pointed out previously in this
paper, if the toxicant is added to water in which test
animals are living, one must consider time of exposure
if the conclusions are to have meaning.  The term Ct,
discussed previously, must be used.  Following from
this  it is  clear  that the term LCtso may be used and
properly so; it is the product of concentration and ex-
posure time that will kill 50percent of the test animals.

   The data on the toxicity of sevin® were rearranged
and recalculated to give approximate results that in-
cluded time of exposure as well as concentration in
milligrams per liter. The results are given in Table
2.   If the data are plotted on logarithmic-probability
paper to give the best straight line, the value for the
                                                        Table 2.  TOXICITY OF SEVIN
                                 TO GOLDFISH
                                                                                                       8
Ct,
mg/min/liter
100,800
86,400
72,000
43,000
Percent dead
100
85
20
20
LCtgg  if  found to be  about  78,000  milligrams per
minute  per liter.   This value  gives a more nearly
accurate  expression of the situation (e.g., the con-
centration of  the toxicant  acting for a given time)
than a  futile  attempt  to  arrive at an  LDso value
without knowing  how  much toxic  material actually
enters the body  of the organism.  There have been
other reports, e.g., toxicity  of  dieldrin to fish, in
which  the LDso  is expressed as parts per million
in the medium (Reference 15, p.  87).  The meaning of
such data  is obscure.
        THE RECTANGULAR HYPERBOLA

   For sublethal concentrations of toxicants in water,
the dose-effect relationships that have been discussed
here  are  of  doubtful value.   The dose-response
curve  encountered  must  frequently,  when  one is
dealing  with sublethal concentrations  of agents, is
the rectangular  hyperbola.  Direct experimental data
support the theory favoring the hyperbola as a widely
applicable  generalization describing the  effects of
pharmacologically active agents on livingprotoplasm. '
   As an example, the  time-concentration  curve for
inducing systolic arrest of the  isolated heart in the
frog, with the toxic agent strophanthin, is described
by the following equation
           (C - 0.5)(t- 2)=K= 30
(3)
where  C  is  concentration  of  drug in parts per 10
million and  t is time  in  minutes.   Likewise, the
entrance of cresyl blue  into Nitella is described ac-
curately by  a hyperbolic time-concentration curve.

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328
                            DETERMINATION OF SAFE LEVELS OF TOXICANTS
   The general function to be anticipated in testing
sublethal  concentrations of water pollutants will be
of the type:
           (X - a) (Y - b) = C
 (4)
where  a, b, and  c are unknown constants.  Fitting
a curve  to points that fall along a hyperbola requires
a modicum of ingenuity.   There  are two  general
methods  for such  curve fitting: the  one suggested
by  Brown  10 and  an alternate method  advised by
Hey and Hey. H

SALMON ORIENTATION

   A good example of the hyperbolic nature of the
dose-effect relationship  at sublethal levels is found
intheworkof Jones and co-workers.  12  The data are
particularly important because they involve meaning-
ful  biological responses to sublethal  concentrations
of water pollutants.  Table  3 summarizes the re-
arranged and  recalculated data.   The  curve  that
fits  the  experimental  points  surprisingly  well is
described as follows
           (X - 120) (y - 20) = 1200
 (5)
where X is  concentration  and y  is the reciprocal
of the mean  percent avoidance (freedom of move-
ment) of  the  salmon.    Figure  1 illustrates the
relationship.
 Table 3.  EFFECT OF SULFITE LIQUOR ON FREE-
          DOM OF MOVEMENT OF CHINOOK
          JUVENILE SALMON
x,
concentration,
ppm
2000
1000
500
250
125
Y,
mean percent
avoidance
82.4
65.4
44.5
25.1
11.4
1/y x 1000,
freedom
of movement
12.1
15.3
22.5
39.8
87.7
                 A relatively simple method of fitting a hyperbola
               to experimental points has been suggested.  13 The
               data in Table  3  were so treated to fit the equation
y = k/x
                                                                                       (6)
               Table 4  shows  the  results obtained with the fitted
               curve
                         y = 10,000/x
                              (7)
               This curve  may give a slightly better fit than does
               equation  (5).The differences are not, however, great.
               Table 4.  CALCULATED VALUES OF Y BASED ON
                         DATA FROM TABLE 3 AND THE EQUA-
                         TION Y = 10,000/X
Let X equal
1,000
500
100
200
400
2,000
800
300
Then calculated y is
10
20
100
50
25
5
12.5
33.3
                  What is clear is the hyperbolic nature of the re-
               lationship between concentration of agent and biologi-
               cal response.

               OYSTER TENTACLES

                  Another good example  of the hyperbolic relation-
               ship  obtaining between the concentration of a toxicant
               and its biological  effect is  found  in the response of
               oysters  to  pulp  mill  pollution.  14   The  delicate
               tentacles along the edge of the mantle in the oyster
               are  sensory in function.   These tentacles retract
               when various  chemical agents come  in contact with
               them.   The  latent period  for  the  retraction is an
               indication of  the  irritating  action of  the agent in
               question.
                            100-
                             50-
                             10
          (X-120) (Y-20) - 1200
                                100
500
      2,000
                                         1,000        1,500
                                   CONCENTRATION, ppm
Figure 1. Avoidance response of Chinook juvenile salmon challenged with various concentrations of sulfite liquor.
        Data from Reference 12.  X, experimental points; ®	® , fitted curve.

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                         The Biology of Water Toxicants in Sublethal Concentrations
                                                329
   Published data 13 were taken and a  curve in the
form of equation (6) fitted to the experimental points
relating  concentration of  pulp  mill  sulfite  liquor
to latent period for oyster  tentacle retraction.  A
good fit is  obtained as illustrated in Figure 2. Note
that  each experimental point is  the  average of 10
observations.
   1.4
   1.2
-o
 8  1.0
in
* 0.8
   0.6

   0.4

   0.2
           12345678

                    CONCENTRATION, ppt

 Figure 2. Relationship of concentration of pulp mill sulfite liquor
         in  parts per thousand to latent  period  for retraction
         of oyster mantle tentacles in seconds.   The ®	®
         hyperbola fitted by using equation y - k/x  '*; X, experi-
         mentally determined points, each based  on 10 obser-
         vations.
FISH BLOOD PRESSURE

   In our laboratory we have  attempted to use blood
pressure changes in fish as an indication of biological
action of toxicants in  sublethal  concentrations.  The
following experiment illustrates again the hyperbolic
nature  of the relationship between amount of agent
and  response.    Dogfish,  Squalus acanthias, were
suitably prepared for recording blood pressure. Then
various  doses  of lysergic acid diethylamide were
administered by vein.  The agent brought about a  rise
in blood  pressure,  which  can be expressed by the
following equation:
                                                                     y = 95.6 -  (5.5/x + 0.04)
                                             (8)
where  y is  the  percent increase in systolic blood
pressure over  control, and  x is the amount of the
agent administered in micromoIs per kg of body weight.
Figure 3 shows the plotted curve.

IMPLICATIONS
   The examples presented show that the biological
action of a toxicant in sublethal  concentrations will
vary with  concentration in a  hyperbolic fashion.  As
concentration of an agent in water increases, the time
required for biological effect decreases to a measur-
able minimum.  Above a certain concentration, C, time
no longer decreases. This minimum time for biological
effect is determined  by  the following  (among other
factors):
   1. Passage  of material through  physiologically
      inactive shell of test animal,
   2. peculiarity of toxicant itself,
   3. circulation time from  point of  entry to site
      of action,
   4. time for action at site,
   5. build-up  of  effective internal  concentration.
The   last   factor involves the rate of detoxication.
                   100
            y
            3*.
                   50
             ^ CO
                    10
                                                                             Y = 95.6-(5.5/x+0.04)
                             0.1     0.2     0.3      0.4      0.5     0.6

                                                    LSD DOSE,/imol/kg
                 0.7
                                                                                  0.8
                                0.9
1.0
           Figure 3.  Hyperbolic relationship of dose of lysergic acid diethylamide to increase in systolic blood pressure as
                    percent of control level in the dogfish, Squalus acanthias.

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330
DETERMINATION OF SAFE LEVELS OF TOXICANTS
   As  concentration decreases,  a point is  reached
at which  no effect follows  even if the toxicant acts
for infinite time.  At this point, Co, the test animals
exposed to the toxicant live as long as the controls,
show no modifications of behavior from that of controls,
and are virtually in the same biological state as the
controls.  Theoretically, then, Co is biological zero
concentration insofar  as the  responses of the test
animal  are   concerned  for  all toxicants other than
carcinogenic chemicals.  C0 is determined by rate
of detoxi cation  and rate of  loss of agent, through
hydrolysis, adsorption, or other ways.

   To  emphasize the biological action of a toxicant,
one can plot the reciprocal of time for effect against
concentration.   The resulting curve is a "curve of
effectiveness"  of  the agent with  respect to a given
biological measure.   This  was  done  in Figure 1,
which  shows  clearly the  effectiveness  of sulfite
liquor  in circumscribing the freedom of movement
of young salmon.

BIOLOGICAL TIME

   When long-term studies are made in which toxicants
are used  in  sublethal  concentrations it is important
to recognize that biological time is a logarithmic
phenomenon.  16  This  fact has been  called to mind
by others. 9  it may partly explain why  dose-response
curves  in which  time  is  an element are of a log-
arithmic nature.

   The  logarithmic character of biological time must
be  kept  in mind when one interprets  long-term ex-
periments' with water toxicants.   It is evident that
the biological value and significance of a given time
interval  will not  be the same at the beginning of a
chronic exposure  as it will be near the termination.
Such  a  consideration  might well be important in
modifying one's conclusions.

            CARCINOGENIC CHEMICALS

   When one is dealing with agents  that have the
capacity to  induce neoplasms in living organisms, a
new dimension is added to toxicological studies.  It
is my  contention that  safe limits or maximum al-
lowable concentrations  have no meaning in reference
to carcinogens.

   Among the classes of chemicals that are known to
be carcinogenic and are found as water contaminants
are polycyclic hydrocarbons, azo dyes, amino  com-
pounds, halogenated hydrocarbons, and urethane.  Some
of these are capable of carcinogenic action in almost
any tissue; others are tissue specific.

   There  is every reason to hold that  carcinogenic
agents  combine with  or exert  profound action  on
various key cellular constituents "so that the heritable

*Reference  17, p. 868.
                            cellular physiology  is  altered  in  the  direction  of
                            uncontrolled proliferation." l?*It is clear, therefore,
                            that one molecule of a carcinogen is all that is needed
                            to  combine with and act on a gene, plasmagene,  or
                            gene-enzyme complex to produce  a cytological al-
                            teration that is heritable.  That one  alteration will
                            then increase  and  multiply until  it  results in de-
                            struction  of the  host.  In brief, this is the basis for
                            denying,  on theoretical grounds,  any  quantity but
                            zero as the maximum  allowable concentration of a
                            carcinogenic toxicant in water  that may be intended
                            for  human  use,  possibly for bathing, but certainly
                            for  ingestion.    From a pragmatic point of view it
                            may be impossible to  demand that all water for
                            human  use be  absolutely  free  of  carcinogens.   In
                            that event,  the toxicologist must be honest and  admit
                            the  risk, which can then  be accepted  or rejected
                            in the light of other economic, political, or emotional
                            considerations.

                              When the  effects of  carcinogens  on aquatic or-
                            ganisms are studied the all-or-none type of experiment
                            is essentially meaningless.  The test animals must
                            be   submitted to a  thorough histopathological study.
                            Great care must be exercised to insure that border-
                            line  responses  are observed.   The  weights of key
                            organs as  related to body weight must be recorded.
                            The constancy of organ weight-body weight ratios in
                            normal fish is well known. 18, 19  The fact that  water
                            contaminants can bring about changes in these ratios
                            has  been  recorded,  20 but this  useful method  of
                            studying water toxicants in sublethal concentrations
                            has not been used to best advantage.

                              In  such assessments especial attention must  be
                            paid to liver and, if possible, kidney weights; for liver
                            and kidney weights are those most frequently affected
                            by a toxicant. 21

                                          GENERAL SUMMARY

                               The few points  made in this paper may be sum-
                            marized briefly.

                            1.  In  an  evaluation of  the lethal  effect of a  water
                              toxicant time is a critical variable.  The product
                               concentration x  time, Ct, is important as a measure
                              of the lethal action of an agent.
                            2.  Toxicants in  sublethal concentrations are biologi-
                               cally important.  The relation of the concentration
                              of  a toxicant, under these circumstances, to the
                              biological  effect is best described by a  rect-
                               angular  hyperbola  and  not by a straight line.
                            3.  For  carcinogenic agents there  is  theoretically
                               no acceptable maximum concentration other than
                               zero.
                            4.  The use of organ-body weight ratios isapromising
                               method for evaluating the effects of water toxicants
                               in sublethal  concentrations.  It should have  wider
                              use.

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                           The Biology of Water Toxicants in Sublethal Concentrations
                                                  331
                                                 REFERENCES
 1.  Stokinger, H.E., 1960.  Water and atmosphere.  Fed-
    eration Proc. 19:26-30.

 2.  Burke, J.A., 1960.  Some  effects of lysergic  acid
    diethylamide and elated agents on embryonic heart
    rate in Fundulus. Biol. Bull. 119:207.

 3.  Burke, J.A., 1960.  Some morphological effects  of
    lysergic  acid  diethylamide and related  agents on
    early  embryonic development  in  Fundulus.   Biol.
    Bull. 119:308.
    Silver, S.D.,  1945.    The  relation  of time to the
  '  dose required to produce a given physiological effect.
    MDR No. 22.  Chemical Warfare Service, Edgewood
    Arsenal, Maryland. 21 pp.

 5.  U.S.  District Court, Rhode Island, Civil Action No.
    2113.  Brief for defendants, pp 51 ff.

 6.  Chadwick,  H.K., 1960.   Toxicity  of tricon  oil spill
    eradicator  to striped bass  (Roccus saxatilis).  Cali-
    fornia Fish and Game.  46 #3 July.

 7.  Clark, A.J., 1937.   General pharmacology.  Vol 4 of
    Hdb. Exp. Pharmakol, ed. W. Heubner and J. Schuiler.
    Berling. Verlag Von Julius Springer. 228 pp.

 8.  Haynes,  H.L., H.H. Moorfield, A.J. Borash, and J.W.
    Keays.,  1958.   The toxicity  of sevin to goldfish.
    J. Econ. Entom. 51:540.

 9.  Gaddum,  J.H.,  1953.    Bioassays  and mathematics.
    Pharmacol.  Rev. 5:87-134.

10.  Brown, R.V.,  1952.  Dose-response  curves for the
    blood pressure effects produced by graded  doses of
    L-epinephrine,  a commercial epinephrine,  and  L-
    norepinephrine.  J. Pharmacol.  Exp. Therap.   105:
    139-155.

11.  Hey,  E.N., and M.H. Hey., 1960.   The  statistical
    estimation of a rectangular  hyperbola.  Biometrics.
    December 1960.  pp 606-617.
12. Jones, B.J., C.E. Warren, C.E. Bond, and P. Doudoroff.
    1956.  Avoidance reactions of salmonid fishes to pulp
    mill  effluents.  Sewage and Industrial Wastes.  28:
    1403-1413.
13. Defares,  J.G., and I.N. Sneddon.  1961.  The math-
    ematics of medicine and biology.  Year  Book Med.
    Publ.  Chicago. 663 pp.

14. Hopkins,  A.E., P.S. Galtsoff,  and H.C.  McMillin.,
    1931.  Effects of pulp mill pollution on oysters.  Bull.
    Bureau Fish. 47:125-186.
15. Rudd, R.L., and R.E.  Genelly.,  1956.   Pesticides:
    their use and toxicity in relation to wildlife. Game
    Bull. No. 7.  California Dept. Fish and Game.  209 pp.

16. DuNony, L., 1937.  Biological time. Methuen. London.
    180 pp.


17. Kirschbaum, A., 1960.  The  carcinogenic  stimulus.
    In  Fundamental Aspects  of  normal  and  malignant
    growth,  ed.  by  W.W. Nowinski.   823-876.  Elsevier.
    New York.


18. Robinson,  P.L., C.G.  Wilber,  and J.  Hunn.,  1960.
    Organ-body  weight  relationship in  the  toadfish,
    Opsanus tau.  Chesapeake Sci. 1:120-122.

19. -Wilber,  C.G., and  P.F. Robinson.,  1960.  The cor-
    relation of length, weight, and girth in  the toadfish,
    Opsanus tau.  Chesapeake Sci. 1:122-123.

20. Krumholz,  L.A.,  1956.   Observations   on the  fish
    population  of  a  lake  contaminated  by radioactive
    wastes.   Bull.  Amer.  Mus. Nat. Hist.  110:277-368.
21. Rowe, V.K., M.A. Wolf, C.S. Weil, and H.F. Smyth.
    The toxicological basis of  threshold  limit  values.
    2. Pathological and biochemical criteria.  Am. Ind.
    Hyg. Assn. J. 20:346-349.

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 332
DETERMINATION OF SAFE LEVELS OF TOXICANTS
                                EFFECTS OFSUBLETHAL CONCENTRATIONS

                       OF ZINC AND COPPER ON MIGRATION OF ATLANTIC SALMON

                                              John B. Sprague *
   In 1960 there was an unusual disturbance of the
spawning migration of adult salmon in the Northwest
Miramichi River,  New Brunswick,  Canada.  Of the
salmon moving upstream during the open-water season,
22 percent returned downstream through a counting
fence maintained by  the Fisheries  Research Board
of Canada.  Previously there had been little down-
stream  movement  from June  through October, the
usual operating period of the fence.  For example,
in the previous 6 years the number of salmon falling
back averaged only 1.5 percent of those moving up-
stream, and  this  figure never exceeded 3 percent
in any one year.

   The  apparent  cause of this disturbed migration
was   sublethal  pollution of the  river by  zinc  and
copper.  This resulted from increased activity during
1960 at a base-metal mine on a  tributary river.
Waters  of  this  tributary were  at  times  lethal to
fish, and bioassays showed that zinc and copper alone
were responsible  for the  toxicity.  The bioassays
were interpreted on the basis of toxicity determined
in the laboratory and analyzed by the "Toxicity Index"
method, which will be described further on.

   Figure  1  shows that downstream movements of
salmon during 1960 occur red when zinc concentrations
were highest in the river.  Zinc is used as a measure
of the  total  pollution by copper  and zinc. Salmon
movements are  summarized  by 5-day periods for
simplicity.  As usual, there was a "spring run" and a
"fall run" of  fish, with heaviest migration during or
after freshets.  The concentration  of zinc also in-
creased during freshets.  Interpolations of the amount
of zinc  have been aided by daily measurements of
water level and by samples taken on different  days
in the polluted tributary.

   During 1961, pollution from the mine was some-
what reduced, and the total downstream movement of
salmon was  14 percent of those going upstream. To
pinpoint the  "safe"  level of  pollution for salmon
migration, water samples for chemical analyses were
taken daily at the counting fence.

   To  express  the zinc and  copper pollution  as a
single number,  a method was used that was recently
developed at the Water Pollution Research Laboratory
in England  (Dept.  Sci. Indust. Res., 1961).   Their
work on the  toxicity of metals to rainbow trout (loc.
cit.;  Lloyd,   1960)  was spotchecked in young Alantic
salmon,  with  excellent agreement.   The variation in
threshold or incipient lethal concentrations with water
hardness has been described (Dept. Sci. Indust. Res.,
1961).
                            Figure 1. Degree  of  metal pollution  compared with disturbed
                                    salmon migration in the Northwest Miramichi River in
                                    1960.  The abnormal downstream movement coincides
                                    with increased pollution as measured by concentration
                                    of zinc.  The apparent  correlation of heavy upstream
                                    movement  with increased  pollution  merely  indicates
                                    that both tend to occur  during freshets. The numbers
                                    of salmon were recorded at the counting fence located
                                    at Curventon, New Brunswick, and were summarized by
                                    5-day periods.  Extensions to the columns by broken
                                    lines indicate that more fish  may have passed during
                                    times of high water when the fence  was partly inop-
                                    erative.

                               To make use of this  method, the incipient lethal
                            concentrations of  zinc and of copper were calculated
                            daily for the Northwest Miramichi River on the basis
                            of  water hardness.   The actual  concentration of zinc
                            in  the  Miramichi was then  expressed as a fraction
                            of  the  incipient lethal concentration.   In this paper
                            the resulting number is called the "Toxicity Index"
                            for zinc, and a value greater than 1.0 indicates a lethal
                            concentration.   The Toxicity Index for copper was
                            calculated in the same way. These two values were
* Fisheries Research Board of Canada, Biological Station, St. Andrews, New Brunswick.

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             Effects of Sublethal Concentrations of Zinc and Copper on Migration of Atlantic Salmon
                                                333
added together to obtain a single Toxicity Index for
zinc and copper.

   In the Northwest Miramichi River, metals were
usually in sublethal  concentrations, and the Toxicity
Index was accordingly less than unity.  Changes in
the  Toxicity  Index  during 1961 are  correlated with
   s300
   <
   U)
 u.
 o
     100 -


  	 0

  z
  O 100
     03-
   x
   UJ
   Q
   5 0 2
                 Apporent  "sofe" I evel
         JUNE 1  JULY   I  AUGI  SEPT  I   OCT  I   NOV
Figure 2.  Degree of metal  pollution  compared with  disturbed
         salmon migration in the  Northwest Miramichi  River in
         1961.  The effects of zinc and copper have been inte-
         grated  and expressed by the Toxicity  Index, as de-
         scribed in the text. A Toxicity Index of  1.0 indicates
         lethal  action of  young salmon after long exposure.  A
         value  of about 0.}5 seems to be the  maximum "safe"
         level  for  undisturbed  salmon  migration.   Explanation
         of salmon movements is given in Fig.  1.
salmon movements in Figure 2.  Inspection of this
figure indicates that a Toxicity Index of approximately
0.15  is the maximum "safe" level for migration of
salmon.   Expressed  as a percentage, this would be
15 percent of the lethal concentration.  A consistent
correlation with salmon movements was not obtained
if  any of  the  three  factors, zinc, copper, or water
hardness,  was  ignored in estimating the degree of
pollution.

   This  work  is being  repeated in  the Northwest
Miramichi River  in 1962 to test the estimated "safe"
Toxicity Index of 0.15.  At the  time of writing there
are not enough data  from  1962  to confirm or negate
this  estimate.    However, preliminary  laboratory
results  indicate  that  young Atlantic salmon  avoid
concentrations  of zinc with a lower Toxicity Index.

   As an example of the amounts of metals involved
in a Toxicity Index of 0.15,  some figures can be given
for water having a total hardness of 20 mg/1 as CaCos.
The incipient lethal concentrations would be 0.7 mg/1
of zinc,  or 0.05 mg/1 of copper.  Multiplying these
by  the Toxicity Index of 0.15, the estimated "safe"
levels would  be  about 0.11 mg/1  of zinc alone or
about  0.008 mg/1   of  copper  alone.   If both 0.11
mg/1  of zinc and 0.008 mg/1 of  copper were present,
the Toxicity Index would be twice the "safe"  level,
thatis,0.15 + 0.15 =0.30.

   I  would like  to   thank Dr.  C. J.  Kerswill for
making available the data on movements of salmon
past  the  counting fence.  Dr. Kerswill is in charge
of salmon investigations for the St. Andrews Biological
Station of  the  Fisheries Research Board of  Canada.
Members of his staff helped in  many ways, including
the collecting of water samples.

REFERENCES

Department  of Scientific  and  Industrial Research.
1961.  Water Pollution Research 1960. H.M. Stationery
Office, London. 122 pp.

1962.  Water Pollution Research 1961. H.M. Stationery
Office, London. 127 pp.

Lloyd,  R. 1960.   The toxicity  of  zinc  sulphate to
rainbow trout.   Ann. Appl. Biol., 48:1:84-94.

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334
                            DETERMINATION OF SAFE LEVELS OF TOXICANTS
         EFFECTS OF COOLING WATER FROM STEAM-ELECTRIC POWER PLANTS ON STREAM BIOTA

                                            F. J. Trembley *
   "All the rivers  run into  the sea; yet the sea is
not full; unto the place from whence the rivers come,
thither they return again." Ecclesiastes 1:7.

   Our problem is: What do we do to a river between
its  source and the sea?  Among many other things,
we  dump  heated water into  rivers.   The subject of
this section of the third seminar is the release of
heated  waters  into  rivers,  lakes, and estuaries.
This subject should not be separated, however, from
the other  subjects under discussion.  Without an eco-
logical  viewpoint all our findings and our painstaking
work will go  very much astray.   Water  cannot be
separated into artificially heated and natural-tempera-
ture water, and water  temperatures cannot be sepa-
rated from all the various types of water pollution and
the biota of the region.
   This report at best can only suggest methods of
approach  to a  big problem, a very  big problem.  The
electrical power industry requires great amounts of
water  as a coolant.   This industry is increasing at
the annual rate of 10 percent in the United  States, 12
percent in Britain, and, lam told, SOpercent in Russia.
A careful estimate of thermoelectricity production in
the 1980's in the U.S.A. is 2,000  bkwh  (billions of
killowatt hours).  This will require about 200 billion
gallons of water per day of which about 6  percent will
be  used for boiler makeup water and 94 percent for
cooling water.

   The  annual  runoff of water for  the United  States
amounts to about 1,200 billion gallons per day; thus in
about a quarter of a  century about one-sixth of all
runoff  waters will be  needed for cooling  and makeup
in steam-electric plants.  This use added to all other
uses—household, industrial,  dilution and  digestion of
wastes, recreation,  etc.—certainly points up a prob-
lem, perhaps  one  of  the biggest  ever  attacked by
American scientists and  engineers.  There is some
chance  that technological advances  may  reduce  the
amount of cooling water needed  by the electric power
industry per unit of production, but not very materially.
After all,  man does not repeal natural laws  that are not
laws in the human sense but only conditions we find in
nature, in this case the cooling ability of water in ref-
erence to its specific heat.

   At this point the term "thermal pollution" should
be discussed.  The  term does not fit.  "Pollution" is
derived from  the  Latin  "polluere," which means "to
make dirty."  Do heated water effluents make a river
or a lake dirty?  They may, but usually  they do not.
If the ecology  of the water is known and thoroughly
understood the word pollution attains a different mean-
ing. It may mean increased basicproduction, lessened
production, or no production and a sterile environment.
   Among the 50 states of the U.S.A. there is little
conformity in laws designed to control heated water.
In some states, heat is called a polluting substance;
it surely would take an Einstein to prove this in court.
Many states  have no laws regulating the release  of
heated water.  In others the release of heated water
is not governed by laws but by rules and regulations
issued  by  a sanitary water board or some similar
state agency.  Since rivers generally flow between
states and across state boundaries, confusion often
reigns.  Without a federal law regulating the release
of heated waters,  states  with  straddling boundary
rivers and lakes must cooperate for control measures.

   Intelligent control of the problem must be based on
surveys of effects of release of heated water  at all
plants and  complete surveys of possible effects  of
heated waters  at all new plant sites.  A working plan
for such surveys is gradually evolving from work al-
ready  done.   Why should state or federal agencies
lay down hard and fast rules without knowing the effects
or the expected effects in a particular area? Surveys
of this type would be initially expensive, but cheap in
comparison to degradation  of the water supply and
constant litigation that might ensue.

   Most steam-electric plants in America use direct
flow of cooling water from a river, lake or  estuary into
a plant and back into the body of water without any
attempttocool or recirculate. In 1959 and January of
1960, through a grant from NSF"f, I observed methods
used  to meet  this  problem in England and Wales.
Through necessity, they have controlled the output of
heated water better than we have.  About 40 percent
of their steam-electric stations use estuarine water,
which  creates problems of corrosion of condenser
tubes by salt water and in some cases excessive growth
of vegetation in areas receiving  the heated water
effluent.  Since no part of the British Isles is over 50
miles from a coastline, estuarine water and sea water
are  used for  cooling much more than in America.
The  remaining 60 percent of the steam-electric sta-
tions use river water; one-half of these use  direct
flow and the other half use the so called "beehive"
natural-draft cooling towers.

   Although these natural-draft cooling towers have
been  suggested for use  in  America, they probably
would not work well here.  England's climate is much
more equable than ours. The cooling towerswould be
least efficient during periods of very high temperatures
and humidity during an American summer when great-
est cooling would be needed.  And during tow tempera-
tures of winter the  towers may fill with  ice (this did
happen in one tower in England).  The cooling of water
by evaporation is a consumptive use. Along 50 miles
of the River Trent, steam-electric stations and cooling
   Professor of Ecology, Lehigh University, Bethlehem, Pennsylvania.
 '  National Science Foundation.

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                Effects of Cooling Water from Steam-Electric Power Plants on Stream Biota
                                                                                                      335
towers are so abundant that 20 percent of the mean
flow of the river is  evaporated.  Pollutants are thus
concentrated in the river, causing a problem.

   Other  problems  result  from  the  use  of cooling
towers, either natural draft  or forced draft. At times
they produce  a heavy fog in the area of the station.
Of course a "wee bit of extra fog* would not be noticed
in Britain.  Sometimes glaze ice forms on roads and
all other surfaces for several miles around an evapora-
ting tower; this rarely happens in England, but much
more often in northern U.S.A. Cooling towers may be
necessary in certain areas to hold temperatures within
reasonable limits; however, their  limitations and ob-
jectionable effects should be realized.

   In England, regulation of heated-water discharge
and  selection of  sites for  new plants are done by a
planning board of the Central Electricity Generating
Board in conjunction with the River Board concerned.
This is another striking difference between British and
American  procedures.  Our rivers  and watersheds
are  much larger than theirs. Moreover,  our rivers
commonly form state boundaries or flow across state
lines and are subject to varying regulations. England's
River  Board  system subjects a whole watershed to
uniform regulations after long, detailed, and continuous
study.

   Although most of our laws and regulations con-
cerning water are founded upon English Common Law,
British barristers have sometimes cited court cases
from America to uphold a water use in England.

   For 5  years,   the  Lehigh  Institute of  Research
studied ecological effects of heated-water discharge
into  the Delaware River at  Martins Creek.  This
research  was supported by the  Pennsylvania Power
and Light  Co.  Because the Delaware River in tbe area
studied is  a  surprisingly clean  river with almost no
pollution,  it  was  an excellent  experimental river.
As is  usual in research,  many preconceived ideas
were found to be wrong. The effects  of heated-water
discharge upon the river biota were not  always  as
expected.  The findings and research methods employed
in this study may be of interest and value in planning
and executing similar projects at other steam-electric
stations.  They can be divided roughly into the following
fields:   Plankton,  periphyton, macroscopic  inverte-
brates, rooted aquatic plants, filamentous algae, fish
population studies, temperature studies, and  chemistry
of the  river water. Brief remarks follow concerning
each of these fields.

   Plankton:  Of the various methods of collecting river
plankton, slow  filtration through  a  millipore  filter
was found to be the best method. Because river plank-
ton drifts with the cur rent, however, and may be in and
out of the study  area in a  matter of a few minutes,
it  was decided that little information could be gained
from plankton studies in a river  of this rapid-flowing
type  and these studies were discontinued.

   Periphyton:  Periphyton includes those organisms
that  cling to  surfaces, usually stones on the bottom.
Most  plankton  organisms  are also  included in the
periphyton.  A modification of the Caterwood Diato-
meter was used to assay the influence of heated water
on  periphyton  populations.  This instrument is es-
sentially a plastic boat  designed to float just below
the surface and holds regular microscope slides behind
a plastic water shield.   Certain organisms, mostly
algae, cling to and develop on the slides. Other organ-
isms including protozoa, diatoms, etc., invade  this
habitat, and within a week, there is a representation
of the periphyton biota. These slides may then be
examined fresh, or stained and kept as a permanent
record.

   The study of the periphyton was very interesting
and  worthwhile.  High temperatures tend to restrict
the  number  of  species present  in an area,  and
may encourage high basic production.

   Macroscopic Invertebrates:  Invertebrates such as
insect larvae,  flatworms, round worms, segmented
worms, mollusca, and crustaceans make up part of
the food  chain for large, catchable fish. With certain
limitations, the Surber square-foot sampler seemed
to be  the  best type  of  collection apparatus.  This
area has fast-flowing  water  over a rough, rubble
bottom with  some sand  banks and mud banks.  The
usual Eckmann Dredge sampling techniques were very
ineffective.

   The macroinvertebrate fauna correlated well with
the periphyton.  The numbers of species in the heated-
water  zone  were  greatly reduced during summer
months.   The  standing  crop  of these  organisms in
some cases  was  increased  during winter  months.
Also, under conditions of highest temperatures  the
standing  crop  remained  constant  or  was  reduced.
Midges, Tendipedidae, seemed to be the most tolerant
invertebrates in the heated-water area.  At the section
of the river where complete mixture of heated water
and normal river water occurred, fresh-water clams,
Unio,  were  often very  abundant.   Other aquatic
invertebrates tend to build up  populations during the
winter months  and  undergo  reduction during  the
summer  months.  The area is constantly   reseeded
by drifting eggs,  larvae, and adults from the river
flow.

Rooted Aquatics: Rooted aquatic plants were extermin-
ated in the river by the great Dianne Flood of August 18,
1955. Their recolonization was watched from 1956 until
1960. At first it was thought that these plants could not
survive in the heated-water area; however, during the
summer  of 1960  a pond weed, Potomongeton,  was
found growing  well in  the  heated-water area with
water temperatures ranging from 95° to 100°F.  We
assumed that this was due to selection of heat-resistant
types.  This  observation should lead to further  re-
search  on tolerant  types  of organisms  in  areas
subjected to heated-water discharge.

   Filamentous Algae:  In a river like the Delaware,
great amounts of filamentous  algae develop in back
bays and shallow  regions close to shore during  late
summer  and early autumn.    An increase in river
stage of a few inches usually occurs in late September
or early October.   This carries  great amounts of
algae down the river.  Old river men speak of this as
"the grass going  out."   Green filamentous algae

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336
                            DETERMINATION OF SAFE LEVELS OF TOXICANTS
tend to grow more rapidly  in areas  of heated water
during  spring  and early summer, but also  tend to
die off before autumn.  In place  of green algae, blue-
green algae develop in great amounts during the warm
months.

   Certain species of  blue-green  algae,  primarily
Oscillatoria,  we found were the most heat-tolerant
organisms.   They were observed growing well at
temperatures  up  to  115°F.  In heated-water areas
during the summer, blue-green algae may make up
most  of  the biomass.   For a number  of reasons
overgrowth of blue-greens may under certain condi-
tions be objectionable. They do not seem to be eaten
by  other  organisms  as much  as  green  algae  and
rooted  aquatics, they  tend to overgrow  themselves,
with consequent release from the bottom and formation
of large  clots  or masses  of dead and dying blue-
greens that float  downriver. Blue-greens are good
nitrogen fixers and when in normal abundance seem to
aid in the basic productivity; however, when exces-
sively abundant, they tend to die off and raise the
biochemical oxygen demand of the river. Blue-greens
clog filters in municipal water  supplies and release
foul odors and  fishy  tastes when they decay.  Some
are actually poisonous.

   For some unknown reason blue-greens do not appear
troublesome in  similar  situations in England.  This
may be because English river  waters do not reach
temperatures as high  as ours,  even  at heated-water
outfalls.   Excessive heat in America  may inhibit
competing green algae and allow overgrowth of blue-
greens, but this does not happen  in England.

   Fish Populations: Fish were taken by seining,  trap
nets, fyke nets, trot lines, electro-fishing, and angling.
Scuba- diving also produced valuable assessment of fish
populations. In  a small lagoon connected with the dis-
charge canal, rotenone was used with excellent results.
This part of the study indicated that most of the fish
species present in the area are attracted to and invade
the heated-water area from late September until early
June.  During the hot summer months fish leave the
heated-water zone.  Forty species of fish were caught
in the heated water  during  the  study.  Attraction to
heated water has been observed in England and has
been reported  frequently  in America. This adds to
the recreational value of these  areas, since angling
can be continued throughout the winter when there is
little  or  no fishing  in other areas.  We found little
evidence that heated waters produce more fish or better
growth rates;  they simply  attract fish and  the fish
actively feed throughout the colder months of the year.
Almost without exception the fish taken in the heated-
water  zone were healthy  and well fed.   In general
they were larger than those of the same species taken
in the normal river.   This  may be due to the active
feeding throughout the winter months, or to a greater
attraction of fully developed fish for warm water.

   We built an experimental fish flume for the study.
Twenty-four species of fish were tested in the flume
for the Median  Lethal   Tolerance  Limit of heat.
Results indicated that if fish were acclimated over a
period of time to high temperatures the lethal tempera-
ture would be considerably  above (3° to 4°)  that ex-
pected as a result of previous  experiments.  There
was  a definite  critical temperature for each species
above which that species  could not survive. The most
resistant  fish  species was  the killifish, Fundulus
diaphanus, which survived 103°F.

   Fish are good  index organisms in polluted areas
and in heated-water areas.  Our  work suggests that'
if time or economic reasons necessitate a short-time
incomplete survey, fish populations should be studied
first. If fish of the  usual species present in a river or
lake invade the suspected area  and remain there,
pollution and other disadvantageous conditions cannot
be very severe.   On the  other hand, if local species
are reduced in numbers or kind,  a thorough investi-
gation should be made.

   Temperature Studies:  Many temperature traverses
of the river below  the station were made over a period
o?  4  years;  most  of these were  from a railroad
bridge below the plant, some by boat below the rail-
road bridge. A thermistor held in a metallic capsule
at the end of a flexible  cable was a very useful and
accurate instrument for thispurpose. Three tempera-
ture-depth profiles of the river were also made with
the "rope trick." A 600 - foot  length of rope was
stretched across  the  river and  pulled  as tight as
possible  with a tackle block. This served as a guide
line  so that temperatures  could be taken every 6
feet  across  the  river  and at every 2-foot level
from surface to bottom.
   These  measurements  gave a  fair picture of the
dispersion and mixing of heated water with the normal
river  water.   Almost complete mixing occurred at
a  point  about  1  mile below the confluence of the
discharge canal and the  river.  Before the construc-
tion  of  diversion jetties to aid mixing of  heated
and normal water, the heated water tended to cling
to the shore  on  the Pennsylvania side  for a much
greater distance.

   We often observed from the railroad bridge a very
clear demarcation between the  heated water and the
normal river flow, usually marked by a line of foam.
The  excellent  papers presented  by C.H. Stranderg
indicate  that the  path of flow of heated water in a
river can be recorded by photography from the air
and  by infrared sensors.   This would seem  to be a
very   significant   advance in the study  of thermal
discharge, which should be correlated thoroughly with
the physiography  of the  study area, the chemistry
of the water, and its ecology.

   Chemical  Studies:  Water chemistry was studied
throughout the course of field observations.  Only
dissolved-oxygen  concentrations are  mentioned here,
since the other values recorded seem to have little
to do with the heated water. We anticipated a serious
loss of dissolved  oxygen  due to heating of the river
water.   On most test dates this was not true.  An
average dissolved-oxygen loss of 0.5 ppm was observed.
Similar observations have been made in England and
in other   parts of America.  This unexpectedly  low
loss may  be due  to the great  turbulence of cooling
water  as it leaves  the discharge structure.  In the
affected  zone of  the river, dissolved-oxygen values
ranged from 4.3 ppm to 10.9 ppm.

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                Effects of Cooling Water from Stream-Electric Power Plants on Stream Biota
                                               337
Suggestions for further work:

   1. Plant sites  should be studied both before and
after installation of generating  systems. Release of
heated  water  is  becoming  a  serious problem,  a
problem that cannot  be  met without adequate data,
especially data from particular plant sites.
   2. Discharge  structures  should  be planned  to
provide as great water turbulence as possible.
   3. Rivers and lakes may be deliberately modified
by  thermal discharges to provide additional recre-
ational fishing during cool-weather periods.
   4. Cooling towers  may  be necessary  to  certain
areas, but their advantages should be weighed against
their disadvantages.
   5. Research on  the effects of thermal discharges
into  rivers,  lakes,  and estuaries should be  con-
tinued indefinitely.
                                            BIBLIOGRAPHY
Agersborg,  H.P.K., 1930.   The  Influence of Tem-
perature on Fish.  Ecology 11:136-144.

Alabaster, John S., 1962. The Effect of Heated Effluents
on Fish, International Conference on Water Pollution
Research,  London, 3-7 September 1962.  28 pages.
Int. Journ. of Air and Water Pollution, pp. 541-563,
Vol. 7, Pergamon Press. N.Y. and London.

Allen, K. Radway, 1940.  Studies on  the Biology of
the Early  Stages  of the Salmon.   (Salmo Salor). I.
Growth in the River Eden. J. Animal  Ecology 9 (1):
1-23.

Andrews, C.W.,  1946.   Effect of Heat on the Light
Behavior of Fish.  Trans. Royal  Society of Canada,
3rd series, 40, Soc. 5:  27-31.

Bailey, R.M., 1955.  Differential Mortality from High
Temperature  in a Mixed Population  of  Fishes in
Southern Michigan.    Ecology 36:  526-528.

Baldwin, E., 1948.   An Introduction to  Comparative
Biochemistry.   164 p.  Cambridge at the Univ. Press.

Banta, A.M., and Thelma R. Wood, 1928. A Thermal
Race  of Cladocera Originated by Mutation. Zeitschr.
Induct.  Abstain  - u.  Vererbugsl.  Supplement b. 1:
397-398.
Bardach,  John  E., and R.G.  Bjorklund, 1957.   The
Temperature Sensitivity of Some American Freshwater
Fishes.  The  American Naturalist 91 (859): 233-251.

Barges, H. Milton, 1950.   Fish Distribution Studies,
Niaugua  Arm of the Lake of the  Ozarks, Missouri.
J. Wildlife Management 19  (1): 16-33.
Battle, H.I.,  1926.  Effects of Extreme Temperature
on Muscle and Nerve Tissue in Marine Fishes.  Trans.
Proc. and Roy. Soc. Can., V, 20: 127-143.

Battle, H.I., 1929. Effects of Extreme  Temperatures
and Salinities on  the  Development of  Enchclyopus
Cimbrius (L.) Contr. Canad. Biol. (N.S.) 5: 109-192.

Baudin, Louis, 1926.  Variation des Echanges Respi-
ratoires  des Poissons en  Function des la Pression
Atmospheriques et de  la  Temperature. Mem. Soc.
Vaudoise, Sci. Nat. 4 (1): 1-40.

Beckman, William C., 1942.  Annulus  Formation on
the  Scales of Certain Michigan Game Fishes. Papers
of the Michigan Academy of Science, Arts and Letters
28:  281-312.
Belding, D.L., 1928.  Water  Temperature  and Fish
Life.  Trans. Amer. Fisheries Society. 58: 98-105.

Bslehradek, J.,  1931.   Influence de la Temperature
sur  la Frequence Cardiaque chez les Embryons  de
la Rousette, Scylliorhinus canicula    L.  C.R.  Soc.,
Biol., Paris 107 (20); 727-29.

Bennett, George  W., and William F. Childers, 1957.
The  Small  Mouth Bass, Micropterus dolomieu,  in
Warm  Water Ponds.    J. Wildlife  Management  21
(4): 414-424.

Binet,  L.,  and  A.  Marin, 1936.   Contributions  a
1'etude  de 1'hypertermie et de 1'asphyxie (recherches
sur  les poissons).   Biol. med., Paris, 26: 329-361.

Binet, L., and A. Marin, 1934.   Action de la Chaleur
sur  les  Poissons.  J.  Physiol,  Et.  Path. Gen. 32
(2): 372-379.


Birge, E.A., C. Juday, and H.W.  March, 1927. The
Temperature of the Bottom Deposits  of LakeMendota:
a chapter in the  heat  exchanges of the lake.  Trans.
Wise. Acad.  Science, Arts and  Letters 23: 187-231.

Bisset,  K.A., 1946.   The Effect of  Temperature  on
Non-Specific Infections  of  Fish.   J.  Pathology and
Bacteriology 58 (2): 251-258.

Bisaet,  K.A., 1948.  Seasonal Changes in the Normal
Flora of Fresh Water  Fish. J. Hygiene 46 (1): 94-97.

Bisset,  K.A., 1948.  The Effect of Temperature Upon
Antibody Production In Cold-blooded Vertebrates. J.
Pathology and Bacteriology 60 (1): 87-92.

Black, B.C., 1947. Respiratory Characteristics of the
Blood  of the Atlantic  salmon,  Salmos solar solar
Linnaeus, Acclimated  to Summer Temperatures  in
Fresh Water.    Trans. Royal  Soc.  Canada  (3)  41
(Sect. I): 198.

Black,E.C., 1953. Upper Lethal Temperatures of Some
British  Columbia Freshwater Fishes. J.  Fish  Res.
Board Can. 10: 196-210.

Black, V.S., F.E.J. Fry, and  Edgar C. Black; 1947.
The  Influence of Temperature  on the Respiratory
Tolerance  of Young Goldfish.   Proc. Nova Scotia
Inst. Science 121: 659.

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338
                           DETERMINATION OF SAFE LEVELS OF TOXICANTS
Bonnet, D.D., 1939.   Mortality  of  the  Cod Egg in
Relation to Temperature. Biol. Bull, Wood's Hole, 76:
428-441.

Borodin,  N.A., 1934.  Survival of Fish in Freezing
Temperatures. Jahrb., Abt. Allg.  Zool. and Physiol.
53: 313-342.

Bowen, E.S., 1932.  Further Studies in the Aggregating
Behavior of Amferus melas.  Biol. Bull. 63: 258-270.

Boycott,  A.E., 1936.  The Habitats  of Fresh  Water
Molluscs in Britain. J. Animal Ecology  5: 116-186.

Breder, C.M. Jr., 1927. Onthe Temperature - Oxygen
Toleration of Brook Trout, Copeia 163: 36-39.

Breder,  C.M. Jr.,  1951.  Studies on the Structure
of the Fish  School.   Bull.  Amer.  Mus. Nat. Hist.
98: 5-27.

Breder, C.M., and R.F. Nigrelli, 1935.  The Influence
of Temperature and Other  Factors on the Winter
Aggregation of the  Sunfish,  Lepomis auritus, with
Critical Remarks  on the  Social Behavior of Fishes.
Ecology 16, No. 1: 33-47.

Brett, J.R.,  1944.  Some Lethal Temperature Re-
lations of Algonquin Park Fishes. Univ. Toronto Stud.
Biol.  Ser. 52: Publ. Ont. Fish Res. Lab. 63: 1-49.

Brett, J.R., 1946.  Rate of Gain of Heat-tolerance in
Goldfish  (Carassius auratus).   Univ.  Toronto Stud.
Biol.  Ser. 53: Publ. Ont. Fish Res. Lab. 64: 9-28.

Brett, J.R., 1952.  Temperature tolerance in young
Pacific Salmon, Genus Oncarhynchus, 3. Fish Res.
Bd. Can.  9: 265-323.

Brett, J.R., 1956.  Some Principles in the Thermal
Requirements of Fishes.  Quart. Review of Biology
31 (2): 75-87.

Britt, N. Wilson, 1955.  New Methods of Collecting
Bottom Fauna from Shoals or Rubble Bottoms of Lakes
and Streams. Ecology 36 (3): 524-525.

Britton, S.W., 1924.  The  Effects of Extreme Tem-
perature  on Fishes.  Amer.  J. Physiol. 67: 411-421.

Brown, L.A., 1929. The Natural History of Cladocerans
in Relation to Temperature.   I. Distribution and the
Temperature Limits for Vital Activities.  The Amer.
Naturalist.    The  Amer,  Naturalist  63: 248-264.

Brown, M.E., 1946.   The Growth  of Brown Trout
(Salmo trutta  Linn.) IV.  The Effect of Temperature
on the Growth of Two-year-old Trout.  J. Exp. Biol. 22
(3-4), Sect. IH: 145-155.

Brues, Charles T., 1927. Animal Life in Hot Springs.
Quarterly Review of Biology 2 (2): 181-203.

Brues, Charles  T., 1928.  Studies  on the Fauna of
Hot Springs  in  the Western United States and  the
Biology of Thermophilous Animals.  Proc. Amer.
Acad. Arts and Sciences 63 (4): 139-228.
Brues,  C.T.,  1939.   Studies on the  Fauna of Some
Thermal Springs in the  Dutch East  Indies. Proc.
Amer Acad. Arts and Sciences 73 (4): 71-95.

Bull,  H.Q.,  1936.  Studies on Conditioned Responses
in Fishes. VII. Temperature Perception in Teleosts.
J. Man. Biol. Assm. U.K. 21: 1-27.

Bullock, T.H.,  1955. Compensation for Temperature
in the- Metabolism  and  Activity of  Poiklotherms.
Biol. Rev. 30: 311-342.


Bullough, W.S., 1939.   A Study of  the Reproductive
Cycle in the Minnow in Relation to the Environment.
Proc. Zool. Soc. Lond. 109: 79-102.

Burger,  J. Wendell, 1939. Some Experiments on the
Relation of the External Environment to the Spermato-
genetic Cycle of Fundulus heteraclitus  (L). Biol. Bull.
77: 96-103.


Burton,  George  W.,  and Eugene  P.  Odum,  1945.
The  Distribution of Stream Fish in  the Vicinity of
Mountain Lake, Virginia. Ecology 26 (2):  182-194.

Cairns,  John Jr., 1956.  Effects of Increased  Tem-
perature on Aquatic Organisms. Industrial Wastes,
March-April.


Cairns,  John  Jr.,  1956.   Effects  of Heat on Fish.
Industrial Wastes, May-June.

Chidester,  F.E., 1924. A Critical Examination of the
Evidence for Physical and Chemical Influences on Fish
Migration.  Brit. J. Exp. Biology 2: 79-118.

Clausen, Ralph G., 1931.  Orientation in Fresh Water
Fishes.  Ecology 12 (3): 541-546.

Clausen, Ralph G., 1939. Body Temperature of Fresh
Water Fishes.  Ecology 15 No. 2: 139-144.

Coker,  R.E., 1933.  Influence of Temperature on Size
of Fresh Water Copepods (Cyclops).   Internat. Rev.
Ges. Hydrobiol. and Hydrograph. 29  (5/6):  406-438.

Coker,  R.E., 1934.  Reaction of Some Fresh Water
Copepods to High Temperatures, with a Note Con-
cerning  the Rate  of  Development  in Relation to
Temperatures.  J.  Elisha Mitchell Scientific Society
50 (1/2): 143-159.

Cole, William H., 1939.  The Effect of Temperature
on the Color Change in Fundulus in Response to Black
and to White Backgrounds in Fresh and Sea Water.
J. Exp. Zool. 80 (3): 167-172.

Collins, G.B.,1952. Factors Influencing the Orientation
of Migrating Anadromous Fishes.  Fish. Bull., W.S.,
52: 373-396.

Cootner, Paul H. A Model for the Estimation of Water
Demand  for  Stream-Electric  Generation.   Water
Resources  for the Future, Inc. Preliminary Draft,
undated.

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                Effects of Cooling Water from Steam-Electric Power Plants on Stream Biota
                                               339
 Courrier, R., 1922.  Seu Pindependence de la glande
 Seminale et des Caracteres Sexuals Secondaires chez
 les Poissons. C.R. Acad. Sci. Paris 174: 70.

 Coutant,  C.C.,  1962.   The Effects of Heated Water
 Effluent Upon Macro-invertebrate Riffle-Fauna of the
 Delaware River, Proc. Penna Acad. of Science, pp.
 58-71, Vol, XXXVI.

 Craig-Bennet, A., 1930.  The Reproductive Cycle of
 the  Three-spined Stickleback. Phil.  Trans. B. 219:
 197.
 Crawford,  D.R., 1930.   Some  Considerations in the
 Study  of the  Effects of  Heat and  Light on Fishes.
 Copeia 73: 89-92.

 Greaser, C.W., 1930. Relative Importance of Hydro-
 gen-ion   Concentration,   Temperature,  Dissolved
 Oxygen and Carbon Dioxide  on Habitat  Selection by
 Brook Trout. Ecology 11: 246-262.


 Dakin, W.J., 1912. Aquatic Animals and Their Environ-
 ment.  The Constitution of the External Medium and
 its Effect  upon the Blood.   Int.  Rev. Hydrobiol.
 Hydrog. 5:  53-80.

 Damann, Kenneth E., 1941. Quantitative Study of the
 Phyto-plankton of Lake Michigan at Evanston, Illinois.
 Butler Univ. Bot. Studies 5 (1/8): 27-44.

 Dannevig,  H.,  1894.  The Influence of Temperature
 on  the Development of the Eggs of Fishes.  Rep.
 Fish. Bd. Scot. 13: 147-153.

 Davenport, C.B., and W.E. Castle, 1895. Studies on
 Morphogenesis.  III.    On  the  Acclimatization of
 Organisms to High Temperature.  Arch Entra. Mech.
 Org. 2: 227-249.

 Davis, R.E.,  1955.  Heat Transfer in the  Goldfish,
 Carassius auratus.  Copeia 13: 207-209.

 Dendy, J.S.,  1944.   Further Studies of Depth  Dis-
 tribution of Fish, Norris Reservoir, Tennessee. J.
 Tenn. Acad. Science 21 (1): 94-104.

Dendy, J.S., 1945.  Predicting Depth Distribution of
 Fish in Three  TVA Storage Type Reservoirs. Trans.
 Amer. Fish Soc. 75: 65-71.

Dendy, J.S.,  1946.  Water Temperature and  Spring
 Fishing.    Norris  Reservoir,  Tennessee.  J. Tenn.
 Acad. Science  21: 89-93.

Dendy, J.S., and R.H. Stroud, 1949.  The Dominating
Influence of Fontana Reservoir on Temperature and
Dissolved Oxygen in the Little Tennessee River and
its  Improvements.   J. Tenn. Acad.  Science 24 (1):
41-51.

Dildine, G.C.,  1936.   The Effect of Light  and  Heat
on the Gonads  of Lebistes. Anat. Record 67, Suppl.
 1:61.
Denys,  H.  Arliss,  and  Jeanne  M.  Joseph,  1956.
Relationships Between Temperature and Blood Oxygen
in the Large  Mouth Bass.  J. Wildlife  Management
20 No. 1. 156-164.

Donaldson, L.R., and F.J. Foster, 1941. Experimental
Study of the Effect of Various Water Temperatures
on the Growth,  Food-utilization, and Mortality Rate
of Fingerling Sockeye Salmon. Trans. Amer. Fish.
Soc. 70: 339-346.

Doty, Maxwell S., and Mikihiko Oguri, 1957. Evidence
for a  Photosynthetic Daily Periodicity.  Limnology
and Oceanography 2 (1): 37-40.

Doudoroff,  P.,  1938.   Reactions of Marine Fishes to
Temperature  Gradients.  Biol.  Bull.   75: 494-509.

Doudoroff,  P.,  1942.  The Resistance and Acclimati-
zation of Marine  Fishes to  Temperature  Changes.
I.  Experiments with Girella nigricans (Ayres). Biol.
Bull.  83:219-244.

Doudoroff,  P.,  1945.  The Resistance and Acclimati-
zation of Marine  Fishes to  Temperature  Changes.
II. Experiments with  Fundulus and Atherinops. Biol.
Bull. 88 (2): 194-206.

Downing,  K.M., and  C.J. Merkens,  1957.   The In-
fluence of  Temperatures  on the Survival of Several
Species of Fish in Low Tensions of Dissolved Oxygen.
Ann. Appl.  Biol. 45 (2): 261-267.

Dryer, William, and Norman G. Benson. Observations
on the Influence of the New  Johnsonville Steam Plant
on Fish and Plankton  Populations.  Tennessee Game
and Fish Commission Report.  10th Annual Conference
Southeastern Association of  Game and  Fish  com-
missioners.

Dutton,  G.J., and J.P. Montgomery, 1958. Glucono-
mide  Synthesis  in  Fish  and  the  Influence of Tem-
perature.   Proc. of Biochem. Society  70  (4): 178.

Ednionson,  Charles Howard, 1929.  Hawaiian Atyidae.
Bernice P. Bishop Museum of Polynesian Ethnology
and Natural History Bulletin 66: 3-36.

Ekberg, Donald  R., 1957.  Respiration of Tissues of
Goldfish  Adapted to Warm and Cold. Dissert. Abstr.
17 (11): 2659.

Ellis, M.M. April, 1947.  Temperature  and  Fishes.
U.S.  Fish and Wildlife Service Fishery  Leaflet 221.

Elson, P.F., 1940.  Effects of Current on the Move-
ment  of Speckled Trout. J.  Fish. Res. Bd. Canada 4:
517-520.

Elson, P.F., 1942.  Effect of Temperature on Activity
of Salvelinus fontinalis. J. Fish Res.  Bd. Canada 5:
461-470.

Embody, G.C., 1934.  Relation of Temperature  to the
Incubation  Periods of Four Species  of Trout. Trans.
Amer. Fish Soc. 64: 281-292.

-------
 340
DETERMINATION OF SAFE LEVELS OF TOXICANTS
Enropeyzena,  N.V.,  1944.  Preferred  Temperatures
of Fish  Larvae. C.R. Acad. Science,  Moscow,  N.S.
42 (3): 138-142.

Fabricius, E., 1950.   Heterogeneous Stimulus Sum-
mation in the Release of Spawning Activities in Fish.
Inst. Freshwater Res. Dritningholm 31: 59-99.

Fish, C.J.,  1927.  Production and Distribution of Cod
Eggs  in  Massachusetts Bay in 1924 and 1925. Bull.
M.S. Buhr, Fish 43 (Part HI): 253-296.

Fish, F.F., 1948.  The Return of Blueback Salmon to
the  Columbia River.   Scient.  Month.  (Wash.)  66:
283-292.

Fisher,  K.C., and P.F.  Elson,  1950.  The Selected
Temperature  of Atlantic Salmon and Speckled Trout
and the  Effect  of Temperature on the Response to
an  Electrical Stimulus.   Physiol. Zool. 23:  27-34.

Foerster, R.E., 1937.  The Relation of Temperature
to the Seaward  Migration of Young Sockeye Salmon
and Speckled  Trout and the Effect of Temperature on
the Response to  an  Electrical Stimulus. Physiol.
Zool. 23: 27-34.

Fraenkel, G., and D.L. Gunn, 1940. The Orientation
of  Animals:    Temperature  Reactions.    Oxford,
Clarendon, 352 pp. Chapter 14.

Fraenkel, G.,  and H.S. Hapf, 1940.  The Physiological
Action of Abnormally High Temperatures in Piokilo-
thermic  Animals.   I. Temperature Adaptation and
the Degree of  Saturation of the Phosphatides.Biochem.
J. 34  (7): 1085-1092.
Freeman,  J.A., 1950.  Oxygen Consumption, Brain
Metabolism, and Respiratory  Movements of Goldfish
during  Temperature Acclimatization,  with  Special
Reference  to  Lowered  Temperatures.   Biol. Bull.,
99: 416-424.

Fry,  F.E.J.,  1947a.   Effects  of the  Environment
on  Animal Activity.  Univ, Tor., Study.  Biol.  Ser.
55: Publ. Ont.  Fish Res. Lab. 68: 1-62.

Fry, F.E.J.,  1947b.   Temperature Relations of Sal-
monids.   Proc, Nat. Comm. Fish  Cult.,  10th Meet.
Appendix "D".

Fry,  F.E.J.,   1948.  Temperature Relations  of  Sal-
monoids.   Proc.   Canada  Comm. Freshwater Fish.
Res., 1st Meet. Appendix "D".

Fry,  F.E.J.,   1951.   Some Environmental Relations
of the  Speckled Trout  (Salvelinus fontinalis).  Proc.
N.E. Atlantic Fish, Conf. May 1951: 1-29.

Fry, F.E.J., 1951.   Some  Temperature Relations of
Fish. Fed.  Proc. 10 (1): 46.

Fry,  F.E.J.,  U.S.   Black,  and  E.G. Black, 1947.
Influence of Temperature on the Asphyxiation of Young
Goldfish  (Carassius  auratus L.) Under Various Ten-
sions of Oxygen  and CX>2. Biol  Bull.  92: 217-224.
                           Fry,  F.E.J.,  J.R.  Brett,  and G.H.  Clawson  1942.
                           Lethal Limits  of  Temperature for Young Goldfish.
                           Rev. Canada. Biol. 1: 50-56.

                           Fry,  F.E.J., ct al, 1942.  Temperature Acclimati-
                           zation. Fish Rev. Canada Biologie 1: 50-56.

                           Fry,  F.E.J., and  O.  Fournier,  1942.   Les Temp-
                           eratures  Lethales  de  Divers Organismes Aquatiques
                           du haut  Saint  -  Laurent.  Res.  Canada Biologie  1:
                           103-104.

                           Fry,  F.E.J., and  J.S. Hart, 1946.  The Relation of
                           Temperature to Oxygen Consumption in the Goldfish.
                           Biol. Bull. 94 (1): 66-77.

                           Fry, F.E.J., and J.S. Hart, 1948. Cruising Speed of
                           Goldfish  in  Relation to Water Temperature. J. Fish
                           Res. Bd.  Can. 7: 169-175.

                           Fry, F.E.J., and K.F. Walker, 1946.  Lethal Temp-
                           erature Relations  for a Sample of Young  Speckled
                           Trout.  (Salvelinus fontinalis).   Univ.  Toronto Stud.
                           Bio.  Ser. 54:  Publ.  Ont.  Fish Res. Lab: 66: 1-35.

                           Fuhrman, F.A., N. Hollinger, J.M. Crimson, J. Field
                           and F.W. Weymouth,  1944.  The Metabolism of the
                           Excised Brain of the Large-mouthed Bass, (at graded
                           temperature  levels).    Physiol.  Zool.  17: 42-50.

                           Galloway, J.C., 1951.  Lethal  Effects  of  the Cold
                           Winter of 1939/40 on Marine  Fishes at Key West,
                           Florida.  Copeia 2:  118-119.

                           Gameson, A.L.H.,  J.W. Gibbs,  and M.J.  Barrett,
                           1959.    A   Preliminary  Temperature  Survey of a
                           Heated River.   Water and Water Engineering. Jan.
                           1959.

                           Gameson, A.L.H., H. Hall, and W.S. Freddy,  1957.
                           Effects of  Heated Discharges on the Temperature
                           of the Thames Estuary.   The Engineer, Dec. 6,13,
                           and 20, 1957.
                           Gerbilisky, N.L., 1937.  Development of Oocytes in
                           Carassius  carassius  and its Dependence  Upon the
                           Temperature.    Bull.  Biol.  Med.  Exper. Moscow
                           3: 160-161.

                           Gibson,  M.B.,  1953.   Upper  Lethal Temperature
                           Relations of the Guppy, Lebistes reticulatus. Canada
                           J. Res. Zool. 32: 302-407.

                           Glaser, O., 1929.  Temperature and  Heart Rate in
                           Fundulus  Embryos,   British  J.  Exper.  Biol.  6:
                           325-339.

                           Gradzinski,  Z., 1949.  The Influence of Temperature
                           Upon the Rate  of the Heart in the Embryos of Teleost
                           Fishes.  Bull. Int.  Acad. Cracovie, 1948, B.II, 7-10,
                           255-93.


                           Gradzinski,  Z., 1950.  The Susceptibility of the Heart
                           in the  Sea-trout Embryo Salmo trutta L. to Small
                           Changes in Temperature.  Bull. International Acad.
                           Polonaise. Sci. Ser.  BH, 4-6: 173-82.

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                Effects of Cooling Water from Steam-Electric Power Plants on Stream Biota
                                               341
Graham, J.N.,  1949,   Some Effects of  Temperature
and  Oxygen Pressure on the Metabolism and Activity
of the  Speckled  Trout, Salvelinus fontinalis. Canada
J. Res. 27 (D) 270-288.

Gray,  J., 1928.  The Growth of Fish, in - The Effect
of  Temperature  on the  Development of the Eggs
of Salmo fario.  British J. Exper.  Biol. 6: 110-130.

Gunn, D.L., 1942. Body Temperature inPoikilotherm
Animals. Biol. Rev., 17: 293-314.

Gunther.  G., 1941.  Death of Fishes due to Cold on
the Texas Coast,  January 1940. Ecology 22: 203-208.

Gutsell, James S., 1929.  Influence  of Certain Water
Conditions, Especially Dissolved Gases, on Trout.
 Ecology 10 (1): 77-96.

Harrington, Robert  Whiting,  1956.   An Experiment
on the  Effects  of Contrasting Daily Photoperiods on
Gametogenesis and  Reproduction in the Centrachid
Fish, Enneacanthus obesus  (Girard) J. of Exp. Zool.
131: 203-224.

Hancock, Hunter  McRau,  1954.   Investigations  and
Experimentation  Relative  to Winter Aggregations of
Fishes  in Canton Reservoir, Oklahoma.  Research
Foundation Publication No. 58. Oklahoma Agricultural
and Mechanical College, Stillwater, Oklahoma.

Hart, J.S.,  1947.  Lethal Temperature Relations of
Certain  Fish  of  the Toronto Region.  Trans. Roy.
Soc. Can. 41: 57-71.

Hart, J.S.,  1952.  Geographic  Variations  of  Some
Physiological and Morphological Characters in Certain
Fresh  Water  Fish.   Univ. Toronto Stud. Biol. Sci.
60, Publ. Ont. Fish Res. Laboratory  72: 1-79.

Hathaway,  Edward S., 1927. The Relations of Temp-
erature to the  Quantity of Food  Consumed by  Fish.
Ecology 8: 428-434.

Hatha-way, Edward S., 1928. Quantitative Study of the
Changes Produced by Acclimatization in the Tolerance
of High  Temoerature by Fishes and Amphibians. Bull.
U.S.  Bureau "of  Fisheries 43 (2): 169-192.

Havgaard, N., and L.  Irving,  1943.  The Influence of
Temperature Upon Oxygen Consumption of the Cummer
(Tautogolubrus  adspersus,  Walbaum) in Summer and
Winter.   J. Cell,  and Comp. Physiol.  21: 19-26.

Hayes,  F.R., 1949.  The Growth,General Chemistry,
and Temperature  Relations of Salmonid Eggs. Quart.
Rev. Biol. 24: 281-308.

Hayes,  F.R., and D.  Pelluet, 1945.  The Effect of
Temperature on  the  Growth and Efficiency of Yolk
Conversion  in the Salmon Embryo.  Canad.  J. Res.
Ottawa 23D: 7-15.
Higurashi,  T., 1925.   Optimum Water Temperature
for Hatching  the  Eggs of  Plecoglossus allireliR. T.
and S.J. Imp. Fish, Inst. Tokyo 20: 12-14.
 Higurashi,  T., 1925.  Optimum Water Temperature
 for Hatching the Eggs of Hypomesus alidus, Pallas.
 J. Imp. Fish. Inst. Tokyo 21: 2-5.

 Higurashi, T., and M. Tauti, 1925.  On the Relation
 Between  Temperature and  the Rate  of Development
 of  Fish Eggs.   J.  Imp.  Fish. Inst.  Tokyo,  21: 5-9.

 H'.ldebrand, Samuel F., and Irving Towers, 1927. Food
 of Trout in Fish Lake, Utah, Ecology 8 (4): 389-397.

 Hile, Ralph, 1941. Age and  Growth of the Rock Bass,
 Ambloplites rupertris (Rafinesque) in Nekish Lake,
 Wisconsin.  Trans. Wisconsin Acad. Science, Arts
 and Letters 33: 189-337.
Ho, H.J., 1936.  The Growth of the Goldfish (Carassius
auratus) China J. Shanghai 24:  101-105.

Hoaglund, Hudson,  1932.  Impulses from the Sensory
Nerves of  Catfish.  Proc. National Acad.  Science 18:
700-705.

Hoar,  W.S.,  1942.  Diurnal Variations  in Feeding
Activity of Young Salmon and  Trout.  J. Fish  Res.
Bd. Canada 6 (1): 90-101.


Hoar,  W.S.,  and M.K. Cottle,  1952a.  Dietary Fat
and Temperature Tolerance of Goldfish.   Canada J,
Res., Zool. 30: 41-48.


Hoar,  W.S.,  and M.J. Cottle, 1952b.  Some Effects
of Temperature Acclimatization on the Heat Tolerances
of Goldfish  (Carrasius auratus).   Can. J. Res. D 27:
85-91.


Hoar, W.S., and J.E.C. Dorchester, 1949.  Effect of
Dietary  Fat on the  Heat Tolerance  of  Goldfish
(Carrasius auratus).   Canada J. Research 27: 85-91.

Holton,  G.D., 1953. A Trout Population Study on a
Small  Creek in Gallath County, Montana.  J.  Wild-
life Mgmt. 117: 62-82.


Hornyold, Alfonso Gandolphi, 1926.  Reduction of the
Body  Size  of Eels During Development  of Pigmen-
tation.   Notos y Resumenes, Inst. Espanol. Oceano
No. 10:  1-8.


Hubbs, C.L.,  1923.  Seasonal Variation in the Number
of Vertebras  of Fishes.   Papers Mich.  Acad. Sci.
2: 217-224.

Hubbs, Clark, 1951. Minimum Temperature Tolerances
for Fishes  of the  Genera  Signalosa and  Herichthys
in Texas.  Copeia 4: 297.

Huntsman,  A.G., 1942. Death  of  Salmon and  Trout
with High Temperature. J. Fish Res. Bd. Canada 5:
485-501.
Huntsman,  A.G.,
Maritime  Stream
6: 476-482.
1946.   Heat  Stroke in Canadian
Fishes. J.  Fish  Res. Bd.  Canada

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342
DETERMINATION OF SAFE LEVELS OF TOXICANTS
Huntsman, A.G., and  M.I.  Sparks, 1924.   Limiting
Factors  for Marine Animals. 3. Relative Resistance
to  High  Temperature.   Contr.  Canada.  Biol.  2:
102-113.

Ide, F.P., 1935.  The Effect of Temperature on the
Distribution of the  Mayfly Fauna of a Stream.  Univ.
of Toronto Studies,  Biol. Ser. 39: 9-76.

Jammes, L.,  1931.  Sur le Compartment, au lac d
(Aredon, de la Truite Commune Salmo  Trutta L.,  en
Function des Agents  Thermique et Nutritifs.  C.  R.
Soc. Biol., Paris  107: 1482-1485.

Kawajiri, M., 1927.  The Optimum Temperature  of
Water for the Hatchings of Eggs of Trout, Oncarhynchus
masacu  (Walbaum), J.  Imp.  Fish. Inst.  3:  14-18.

Kawajiri, M., 1927.  On the Optimum  Temperature
of  Water for  Hatching  the  Eggs of  Rainbow Trout
(Salmo  irideus,  Gibbon).   J.  Imp.  Fish  Inst. 23:
59-64.

Kawajiri, M.,  1928.   The Influence of Variation  of
Temperature of  Water on the  Development  of Fish
Eggs.   On  the  Relation of  Growth and Death from
Starvation of the Trout Fry to  Temperature.  On the
Studies of the Population - Density of Cultured Fishes.
J. Imp. Fish. Inst. Tokyo 24: 1-12.

Kennedy,  W.A., 1940.  The  Migration of Fish From
a Shallow to a Deep  Lake in Spring and Early Summer.
Trans. Amer. Fish. Soc.  70: 391-396.

Ketchen, K.S.,  1952. Factors Influencing the Survival
of  the Lemon  Sole (Parophrys netulus, Girard)  in
Hecati Strait,  British  Columbia.  Univ. Tor., Dept.
Zool. Ph. D. Thesis.

King, J.E., 1943. Survival Time of Trout in Relation
to  Occurrence.   Amer. Midi. Nat.,  29: 624-642.

Krough, A., 1939. Osmoregulation in Aquatic Animals.
242 pp. Cambridge,  at the Univ. Press.

Kropp,  B.N.,  1947.  The Effect of Temperature on
the Rate  and  Variation  of  Opercular  Movement  in
Fundulus  diaphanous  diaphanous.   Canada J. Res.
25D 2: 91-95.

Kubo, T., 1936. Feeding  Velocity of the  Eel, Anguilla
japonica  (T&S) in Relation to Water Temperature and
Other Environmental Conditions.  Bull. Jap. Soc. Sci.
Fisheries 4: 335-338.
Kubo, T., 1953.  On the Blood of Salmonid Fishes of
Japan during Migration. 1.  Freezing Point of Blood.
Bull. Fac. Fish Hakhaida Univ.  4: 138-148.

Kujiyama, E., 1929.  On the Influence of Temperature
Upon the Development of Eggs of Pograsomas major
(T&S), J. Imp. Fish Inst. Tokyo 24: 109-113.

Laberge, Ronald H., 1959. Thermal Discharges. Water
and Sewage Works, December, 1959.
                           Langbein,  Walter  B.,  et al.   Annual Runoff in the
                           United States.  Circular 52.  U.S. Geological Survey,
                           1949.

                           Lawrence, W.M., 1940.  The Effect of Temperature
                           on the Weight of Fasting Rainbow Trout Fingerlings.
                           Trans. Amer. Fish Soc. 70: 290-296.

                           LeBosquet, M.,  Jr., 1946.  Cooling Water Benefits
                           from  Increased River  Flows.  J. New England Water
                           Works Assoc. 60 (2): 111-116.

                           LeBourueau, John  W.,  1959.  Second Report of Deer-
                           field  River  Study  by  Yankee Atomic Electric Co.
                           Yankee Atomic Electric Co., 441 Stuart St., Boston,
                           Mass.


                           Ljubtzky, A.I., 1935.   I. Zur Erforshung des Temp-
                           erature effects  in  du  Morphogenese.  II. Einfluss
                           der Temperatur  auf die Entwichlungsgerchwindigkeit
                           und Wachstrum des  Embryos von Salmo trutta, fario.
                           Zool.  Jahr B. Jena (Allg. Zool.) 54: 405-422.

                           Loeb,  J., and H. Wastenys, 1912.  On the Adaptation
                           of Fish.   (Fundulus) to High  Temperature. J. Exp.
                           Zool.  12: 543-557.

                           Lund,   J.W.G., and J.F.  Tailing,  1957.   Botanical
                           Limnological  Methods  with Special  Reference to the
                           Algae. The Botanical Review 23: 489-583.

                           MacArthur, John W., and William N. T. Baillie, 1929.
                           Metabolic  Activity and Duration of  Life. I. Influence
                           of  Temperature on Longevity in  Daphnia  magna.
                           J. Exper. Zool. 53 (2): 221-242.

                           MacCardle, R.C., 1937.  The  Effect of Temperature
                           on Mitochondria in Liner Cells of Fish. J. Morphology
                           61: 613-639.

                           MacKichan, Kenneth A.  Estimated Use of Water in
                           the United States, 1955. Circular 398. U.S. Geological
                           Survey, 1957.

                           Markowski, S., 1959.   The Cooling Water of  Power
                           Stations. A New Factor in the Environment of Marine
                           and Fresh Water  Invertebrates.   Journal  Animal
                           Ecology 28 (2): 243-258.

                           Marrow, J. E., Jr., and A Mauro, 1950. Body Tem-
                           perature of Some Marine Fishes.  Copeia 2: 108-116.

                           Marsui, K., 1940.   Temperature  and Heartbeat in a
                           Fish  Embryo, Oryzias latipes. I.  The Relation of
                           Temperature  Coefficient of  Heartbeat to Embryonic
                           Age.  Sci. Rep.  Tokyo Bun. Daig, 5B, 81-83: 39-51.

                           Matsui, K., 1943.   Temperature and Heartbeat in a
                           Fish  Embryo,  Oryzias latipes,  IV.  The arrest of
                           Heartbeat  by  Heat. Sci. Rep. Tokyo, Bun. Daig. 6B,
                           95-98: 129-138.

                           Mattley, C. McC., 1931.  The Effect of Temperature
                           on  the Number  of Scales in Trout.  Science 74:
                           316.
                                                                                               GPO 816-361 —i

-------
                Effects of Cooling Water from Steam-Electric Power Plants on Stream Biota
                                              343
 McCay, C.M., L.A. Maynard, J.W. Titcomb, and M.F.
 Crowell, 1930. Influence of Water Temperature Upon
 the Growth and Reproduction of Brook Trout. Ecology
 11: 30-34.

 McFarland, W.M., 1955. Upper Lethal Temperatures
 in the Salamander,  Taricher torasa, as a Function
 of Acclimation.  Copeia 3: 191-194.

 Medlen,  A.B., 1951.   Preliminary  Observations  on
 the  Effects of Temperature  and Light Upon Repro-
 duction in  Cambusia  affinis.   Copeia 1951, No.  2,
 148-152.

 Meek, E.M., 1922. Effect of Temperature on Growth
 of Young Blennies (Zoarces Vivparous), Dove Marine
 Lab. Rep. 11: 102.

 Meeting  Tomorrow's   Power Needs.    June  1960.
 Edison Electric Institute.  Bulletin No. 60-36.

 Merriman, D., 1935.  The Effect of Temperature  on
 the Development  of the Eggs and Larvae of the Cut-
 throat Trout (Salmo clarkie  clarkie) Richardson.  J.
 Exp. Biol. 12: 297-305.


 Meuwis,  A.L., and M.J. Heuts,  1957.   Temperature
 Dependence of Breathing  Rate  of Carp.  Biol. Bull.
 112 (1): 97-107.

 Miller, William   T.,  1956.   Possible Relationship
 of Water  Temperatures with Availability and Year
 Class  Size  in the Pacific Sardine. M.A. Thesis  in
 Biological Sciences, Stanford Univ. 1956.
Naumann, Einar,  1927.  Critique of the Plankton Con-
cept. Arkiv Bot.  21 A (3): 11-18.

Nicholls, J.W.V., 1931.  The Influence of Temperature
on Digestion in Fundulus heteroclitus.  Contr. Canada
Biol. 7: 45-55.

Nielson, E.T., 1938.  Thermoelectric Measurement
of the Body Temperature of Mice and Fishes. Acta.
Med. Scand. 90: (SuppL): 169-189.

Odum, Eugene P.,  Fundamentals of Ecology 2nd ed.,
W.B.  Saunders and Company,  1959, Philadelphia.

Orr, Paul,  R.,  1955.  Heat  Death.   I.  Time-Tem-
perature Relationships  In Marine Animals.  Physiol.
Zool. 28 (4): 290-294.

Oya, T.,  and  M. Kimata.   Oxygen  Consumption of
Fresh Water  Fishes.   Bull. Jap. Soc. Science Fish
6 (6): 287-290.

Patrick, R.,    M. H. Hahn, and J.H. Wallace, 1954.
A New Method for Determining the Pattern of Diatom
Flora. Norulae Naturae, Academy of Natural Sciences
of Philadelphia #259: 1-12.

Pearse, A.S., and F.G. Hall, 1928.  Homoithermism.
The Origin of Warm  blooded Vertebrates. 119  pp.
John Wiley and Sons, N.Y.

Peiss, C.M.,  and J. Field, 1950.  The  Respiratory
Metabolism of Excised  Tissues of Warm and Cold
Adapted Fishes.  Biol. Bull., 99 (2): 213-224.
Moore, J.A., 1949.  Patterns of Evolution in the Genus
Rana.  In Gnetics, Paleontology, and Evolution. Jepson,
G.T., E. Mayr and G.G. Simpson, Eds. pp.  315-338.
Princeton Univ. Press, Princeton.

Moore, Walter, G.,  1942. Field Studies onthe Oxygen
Requirements of Certain Freshwater Fishes. Ecology
23: 319-329.
Mossman,  William  H.,  and  Anthony  L. Pacheco,
1957.   Shad  Catches  and Water Temperatures  in
Virginia.   J. Wildlife Management 21  (3): 351-352.

Musacchia,  J., and  M.R. Clark, 1957.  Effects  of
Elevated Temperatures on Tissue Chemistry of the
Arctic Sculpin, Myxochephalus quaricornis. Physiol.
Zool. 30 (1): 12-17.

Nakai, N., 1927.  On the  Influence of Water Tem-
perature Upon the Development of the Eggs of Leucisus
hakuensis Gunther.   J.  Imp, Fish. Inst. Tokyo 22:
73-85.
Nakai,  N.,  1928.    On the  Influence of the Water
Temperature Upon the Hatching of Eggs of Hypomessus
alidus.  Pallas. J. Imp. Fish Inst. Tokyo 23: 124-127.

Nakai, N., 1928.  On the Influence of Temperature
Upon  the Hatching of Eggs of Plecoglossus altinesis
(T&S). J. Imp. Fish. Inst.  Tokyo 24: 28-37.
Penfound, William  T., 1956.  Primary Production
of Vascular Aquatic Plants.   Limnology and Ocean-
ography 1 (2): 92-101.

Picton,  Walter  L.  Water Use in  the United States,
1900-1975.   Business Service Bulletin 136.  Water
and  Sewerage Industry and  Utilities Division, U.S.
Dept. of Commerce, January, 1956.

Pitt,  T.K.,  E.T. Garside, and R.L. Hepburn, 1956.
Temperature Selection of the Carp (Cyprinus carpio
Linn.).  Canada.  J. Zool. 34: 1555-557.

Powers,  Edwin, B.,  et al,  1932.   The Relation of
Respiration  of  Fishes to  Environment.   Ecology
Monographs 2 (4); 385-473.

Powers,  Edwin  B.,  1937.   Factors Involved  in the
Sudden Mortality of  Fishes.   Trans.  Amer. Fish.
Soc. 67: 270-280.

Pratt, David M., 1943. Analysis  of Population De-
velopment  in Daphnia at  Different Temperatures.
Biol. Bull. 85 (2): 116-140.

Price, J.W.,  1940.   Time-Temperature  Relations
in  the  Incubation  of the White  Fish,  Coregonius
clupeoformis (Mitchell). J. Gen. Physiol. 23:449-468.

Prosser,  C.  Ladd.   Physiological  Variations  in
Animals. Biol. Review 30 (3): 229-262.

-------
344
DETERMINATION OF SAFE LEVELS OF TOXICANTS
Prosser, C.L., F.A. Brown, D.W. Bishop, T.L. John,
andV.J. Wulff., 1950. Comparative Animal Physiology
W.B.  Saunders  Co., W. Washington Square, Phila.,
Pa., 888 pp.

Provasoli,  Luigi,  1958.  Nutrition and  Ecology of
Protozoa and Algae.  Annual Review of Microbiology
12: 279-303.

Raffy,  A.,  1952.   Influence  des  Variations de  la
Temperature seu 1'osmoregulation des Petites Carpes
en eau Douce it en eau Salee, Compte Rendus Societe'
de Biologic 146: 908-910.

Ricker,  W.E., 1934.  An Ecological Classification of
Certain Ontario Streams.  Univ. Toronto Stud. Biol.
Ser. 37.  Publ. Ont. Fish Res. Lab 49: 1-114.

Ross, F.F., 1958.  The Operation of Thermal Power
Stations in Relation to Streams. The Institute of Sewage
Purification,   Annual Conference, Southport, 24-25th
June,  1958.   Conference paper No. 7.  10 Cromwell
Place, South Kensington, London, S.W.7.

Sand,  A., 1938.   The  Function  of the Ampollae of
Lorenzii with Some Observations  on  the Effect of
Temperature on Sensory Rhythms. Proc. Roy. Sec.
London  125 B, 841: 524-553.

Sanderson, Albert E.,  Jr. Comments Relating to the
Proposed Discharge of Water of High Temperatures
Upon  the Natural  Resources of the  State of Maryland
in the Potomac River  near Dickenson, Montgomery
County  (Pot.  Elec. Power Co.) Game and Inland Fish
Commission.

Schaperclaus, W.,  1927. The Acidity of Fresh Water
and Its Relation to Fish.  Sitzungsker Ges Naturfarsch
Freunde. Berlin 1927 (1/3): 1-9.

Scholander, P.F., W. Flagg,  V. Walters, and L.Irving,
1953.    Climatic Adaptations in Arctic and  Tropical
Poikilotherms.  Physical Zool. 26: 67-92.

Schultz, L.P., 1927. Temperature Controlled Variation
in the Golden Shiner,Notemigonis crysoleusus. Papers
Mich. Acad., Ann Arbor 7: 417-432.

Sette, A.E., 1950.   Biology  of the  Atlantic Mackerel
(Scomber scombuis)  of  North America, Part II.
Migrations and Habits.  Fish Bull. U.S. 49: 251-258.


Simpson,  A.C., 1953.    Some  Observations on the
Mortality of  Fish  and the  Distribution of  Plankton
in the Southern North Sea  during  the Cold  Winter,
1946-1947.  J.  Cons. Mt. Explor.  Mer. 19: 150-177.

Shaw, Paul A., 1946.  Oxygen Consumption of Trout
and Salmon.  California Fish and Game 32 (1): 3-12.

Shultz, L.P.,  1927.  Temperature Controlled Variation
in the Golden Shiner, Notemigonus crysoleucus. Papers
Mich. Acad. 7: 417-432.

Smith, D.C.,  1928.  The Effect of Temperature on the
Melanophores of Fishes. J.  Exper.  Zool. 52:183-234.
                           Smith, D.C., 1931. TheEffectof Temperature Changes
                           upon  the Pulsations of Isolated Scale Melanophores
                           of Fundulus  heteroclitus.   Biol.  Bull. 60: 269-287.

                           Smith. L.L., et al, 1955. Stream Pollution. Aquatic
                           Life Water Quality Criteria. First Progress Report.
                           Aquatic Life Advisory Committee of the Ohio River
                           Valley Water  Sanitation  Commission.  Sewage and
                           Industrial Wastes 27 (3): 321-331.

                           Smith, L.L., et al, 1956. Stream Pollution. Aquatic
                           Life Water Quality Criteria. Second Progress Report.
                           Aquatic Life Advisory Committee of the Ohio River
                           Valley Water  Sanitation  Commission.  Sewage and
                           Industrial Wastes 28 (5): 678-690.

                           Storey, M., 1937.  The Relation Between Normal Range
                           and Mortality of Fishes Due to Cold at Sanibel Island,
                           Florida.  Ecology 18: 10-26.

                           Strandberg, C.H., 1962.   Dispension and Diffusion of
                           Heated Coolant Water.  General  Research and De-
                           velopment, Inc., 112 Wayne  St. Arlington, Va.

                           Strandberg, C.H., 1962. Analysis of Thermal Pollution
                           from the Air, 17th Purdue Wastes Conference, Purdue
                           Univ. W. Lafayette, Ind.

                           Sullivan, C.M., 1949.  Aspects  of the Physiology of
                           Temperature Selection in Speckled Trout (Salvelinus
                           fontinalis)  Univ.  Toronto, Dept. Zool. Ph.D. Thesis.

                           Sullivan, Charlotte M,, 1954. Temperature Reception
                           and  Responses in Fish.  J.  Fish. Res. Bd. Canada 11
                           (2): 153-170.

                           Sullivan,  C.M., and  K.C.  Fisher,  1953.   Seasonal
                           Fluctuations in the Selected Temperature of Speckled
                           TROUT,  Salvelinus fontinalis.  (Mitchell). J.  Fish.
                           Res. Bd. Can. 10: 187-195.

                           Sumner,  F.B.,  and P. Doudoroff, 1938.  Some Ex-
                           periments  Upon  Temperature  Acclimatization and
                           Respiratory  Metabolism in Fishes.   Biol. Bull.  74:
                           403-429.

                           Sumner,  F.B.,  and A.N. Lanahanm, 1942.  Studies of
                           the Respiratory Metabolism of Warm and Cool Spring
                           Fishes.  Biol. Bull. 82: 313-327.

                           Sumner,  F.P.,  and M.C. Sargant, 1940.  Some Ob-
                           servations on the Physiology of Warm Spring Fishes.
                           Ecology 21:45-54.

                           Sumner,  F.B.,  and N.A. Wells, 1935.  Some Relations
                           Between   Respiratory Metabolism  in  Fishes  and
                           Susceptibility   to  Certain  Anaesthetics  and  Lethal
                           Agents.  Biol. Bull. 69 (3): 368-378.

                           Swain, A., and C.F.  Newman,  1957.  Hydrographical
                           Survey of  the River Usk. Fishery  Investigations,
                           Series, I. Vol. VI., No. 1.

                           Tarzwell,  C.M.,  and A.R.  Gaufin,  1958.    Some
                           important Biological Effects of Pollution Often Dis-
                           regarded  in  Stream  Surveys,   Proc. 8th  Purdue
                           Industrial Waste Conference.

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                Effects of Cooling Water from Steam-Electric Power Plants on Stream Biota
                                               345
Tauti, M., 1927.   On the Influences of Temperature
and  Salinity  Upon the Rate of Development of Fish
Eggs.  J. Imp. Fish, Inst. Tokyo 23: 31-37.

Tauti, M., 1928.  On the  Influence of Temperature
of  Water  Upon  the  Hatch Rate and  the  Hatching
Days of Fish  Eggs.   J.  Imp.  Fish,  Inst.  Tokyo 24
(1): 13-18.

Thornton, Frederick  E., 1932.  The Viscosity of the
Plasmogel of Amoeba proteus  at Different  Temp-
eratures.  Physiol. Zool. 5 (2): 246-253.

Trembley, F.J., 1960.  Research Project on Effects
of Condenser Discharge Water  on Aquatic  Life.  I.
Progress  Report  1956-59.   November 21,  1960.

Trembley, F.J.,  1961.  II Progress Report, 1960.
April 21, 1961.   Lehigh University Institute of  Re-
search, Bethlehem, Pa. Unpublished.

Truesdale, G.O., and  K.G. Van Dyke, 1958.  Effect
of Temperature on Aeration of Flowing Water. Water
and Waste Treatment Journal 7: 9-11.

Van Oosten, John,  1944. Factors Affecting the Growth
Rate of Fish.  Tranft. North Amer. Wildlife Conf. 9:
177-183.

Van  Vliet, R., 1957.   Effect of Heated Condenser
Discharge Water Upon Aquatic Life, ASME Paper  No0
57-PWR-4.

Vaux,  D.,  1953.   Hydrographical  Conditions in  the
Southern North Sea During the Cold Winter of 1946-
1947.   J. Cons. Int. Explor.  Mer.  19:  127-149.

Velz, C.J., 1939.  Deoxygenation and Reoxygenation.
Trans. Amer. Soc. Civil Eng. 104: 560-578.

Velz, C.J., 1944. Factors Influencing Self-Purification
and Their Relation to Pollution Abatement.  Sewage
and Industrial Wastes 19: 629-644.

Verduin, Jacob, 1960.  Letter in Science 131, p. 232,
January 22, 1960.

Verril,  A.E., 1901.   A Remarkable Instance of  the
Death of Fishes at Bermuda in 1901.  Amer. J. Sci.,
Ser.  4, 12: 88-95.

Walford, L.A., 1938.   Effect of Currents on the Dis-
tribution and  Survival of the Eggs and Larvae of the
Haddock (Melanogramnus aeglefinus) on Georges Bank,
Bull. U.S. Bur. Fish. 49: 1-73.

Wallace, N.M., 1955.   The Effect of Temperature on
the Growth of Some Fresh Water Diatoms.  Not. Nat.
Acad. Nat. Sci. #280.
Ware, G.C., 1958.   Effect  of  Temperature on the
Biological  Destruction of Cyanide. Water and Waste
Treatment Journal 6: 537.

Watts, R.L., and G.W.  Harvey,  1946.  Temperature
of Kettle  Creek and  Tributaries in Relation to Game
Fish.   Bull.  Penna  Agric. Exp.  Sta.  481:  1-30.

Wells, Morris  M.,  1914.  Resistance and Reactions
of Fishes  to Temperature.   Trans.  Illinois  Acad.
Science 7: 48-59.

Wells, Nelson A., 1935.  Variations in the Respiratory
Metabolism of the Pacific Killifish, FunduLusparuip-
pinis,  Due  to Size, Season,  and Continued Constant
Temperature. Physiol. Zool. 8:  318-336.

Wickwire, G.C., LJX Sager, W.E. Burge, 1929a Com-
parative  Effect  of  Temperature on  Rate  of Pure
Chemical Reactions and Rate of Sugar Utilization by a
Plant  and  on Cold  Blooded Animal (Spirogyra and
Goldfish).  Bot. Gaz. 88 (4): 430-436.

Williams,  A.E.,,  and R.K. Burris,  1952.  Nitrogen
Fixation by Blue-Green Algae and Their Nitrogenous
Composition,, Am. J. Botany 39: 340-342.


Wingfield, C.A., 1940. The Effect of Certain Environ-
mental Factors on the Growth of Brown Trout  (Salmo
trutta ).  J. Exp. Biol. 17: 435-438.

Wood, A.H., 1932.  The Effect of Temperature on the
Growth and Respiration of Fish  Embryos  (Salmo
fario) J. Exper. Biol. 9: 271-276.

Woodward, D.R.  Availability of Water in the United
States with Special Reference  to  Industrial Needs
by 1980.  Thesis No. 143.  Industrial College of the
Armed Forces, April 1957.

Yamamoto,  T., 1931.  Temperature Constant for the
Rate of Heart Beats  in Oryzias latipes.  J, Fac. Sci.
Imp. Univ. Tokyo. Zool. 2: 381-388.

Yamamoto, T.,  1937.  Influence of Temperature on the
Embryonic Development of the Pond Smelt, Hypomesus
alidus.  Pallas  Bull.  Jap.  Soc.  Sci,  Fish Tokyo  5:
326-332.

Yamamoto,  T.,  1937.  Influence of Temperature on
The  Embryonic Development of the European Carp
Carassius carassius  Linneaus.   Bull. Jap.  Soc. Sci.
Fish Tokyo 5: 326-332.


Yount, James L., 1956.  Factors that Control Species
Numbers in Silver  Springs, Florida.  Limnology and
Oceanography 1: 286-295.

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346
                            DETERMINATION OF SAFE LEVELS OF TOXICANTS
           THE CONTRIBUTION OF BOTTOM MUDS TO THE DEPLETION OF OXYGEN IN RIVERS,

                         AND SUGGESTED STANDARDS FOR SUSPENDED SOLIDS

                                            Peter C. G. Isaac *
   The  title  of  this  brief introductory review is a
portmanteau  holding a number of implicit questions.
A  clear statement of these questions will be of as-
sistance in   enabling us to assess their importance
and to judge how far we have gone towards answering
them. These questions are:

   1. Do bottom muds  contribute to  oxygen demand
     in rivers?
   2. To what extent is this oxygen demand exerted
     by products of dissimilation  in the  sediment
     layer?
   3. To what extent are bottom muds  resuspended
     in the flowing water ?
   4.  Do they then exert an oxygen demand?
   5. Can we  limit  bottom  deposits by  imposing
     suspended solids standards on effluents?
   6. What rational criteria  can we apply to such
     standards ?

   Even if the author's commission had called for it,
a definitive  review of the  topic is impossible at the
present time.   Perhaps rightly, this matter seems
to have been very largely ignored, and what literature
there is does not, unfortunately, lead to a consistent
conclusion.   The author has, therefore, set himself
the task of drawing together  the results of some of
the more important  investigations  as they bear on
the six questions.

   On the face of it fairly firm answers of Byes" can
be  given  to  questions (1) and  (4), but even these
questions  are  well worth discussion.   The  other
questions are still open.

   The bottom deposits that are built up in a  receiving
water  vary  in  location,  composition, and  quantity
with:
   a. The  character and  amount  of waste  matter
     entering the water (including, of course, material
     eroded from the catchment);

   b. the hydraulics of the body of water;

   c. the rate and nature of decomposiiton of organic
     matter  in the deposit.
   If the supernatant water contains dissolved oxygen,
aerobic  conditions  will  exist  only  at  the surface
layer of the sediment because the diffusion of oxygen
is normally  so slow  that the lower layers remain
anaerobic.  Decomposition of the lower layers will,
therefore, be  anaerobic, while the upper layers will
be stabilized  aerobically.   The  term "benthal de-
composition" has been applied to this combination of
anaerobiosis and aerobic stabilization.
DO  BOTTOM  MUDS  CONTRIBUTE  TO  OXYGEN
DEMAND IN RIVERS?

   The  Royal Commission on Sewage Disposal ex-
haustively  examined  the whole  question  of  sewage
disposal and river pollution in England and  Wales
between 1898 and 1915, and published many voluminous
reports.    In particular  the lengthy Appendix to the
Eighth  Report  (1913)  bears on this  matter.    On
several occasions (e.g., pp. 116, 118) the  authors of
this  Appendix state categorically that fouling of the
stream bottom is responsible for further deoxygenation
of the water flowing over it.  This comment is based
on extensive observation of many English rivers by
outstanding investigators. We can, I think, therefore,
accept "yes"  as the answer to our first question.

   First, however,  we must take notice of a compli-
cating factor:  suspended solids interfere with the
dissolved-oxygen determination (Ruchhoft and Moore,
1940;  Forth River Purification Board, 1959).   The
Forth survey  showed  that high concentrations of
suspended  solids reduced the apparent oxygen con-
centration  by 10 to 25 percent.  Nevertheless, even
allowing for this, it is clear that river muds, if they
do become resuspended in the stream flow, can  make
a  substantial  contribution to oxygen  demand - but
this  is a  topic to which we must return in looking
at questions (3) and (4).


   In accepting the affirmative  answer to our first
question it is  worth noting  that we are  concerned
with at least three cases that differ in the importance
accorded to the likelihood of resuspension:

   a. A  nontidal   river in which  resuspension is
      possible only at times of increased river flow,
      i.e.,freshet or flood;

   b. a tidal estuary with  such a very large water
      volume (and such a shape) that resuspension is
      unlikely to be  appreciable in relation to the
      total water body except in the case of violent
      storm;

   c. a tidal  river in which resuspension is likely
      at each flood tide, e.g.,the upper portion of the
      Forth estuary (Forth River Purification Board,
      1959; Collett, 1961).

   It will  be  readily  appreciated that the relative
contributions to oxygen demand of the settled deposit
and  of the resuspended solids will vary quite widely.
It is likely also  that the  total contribution of the
solids will be greatest where resuspension is greatest.
  Reader in Public Health Engineering, University of Newcastle upon Tyne, Newcastle upon Tyne, Great Britain.

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                  The Contribution of Bottom Muds to the Depletion of Oxygen in Rivers
                                              347
 TO  WHAT EXTENT IS  THIS  OXYGEN DEMAND
 EXERTED BY PRODUCTS OF  DISSIMILATION  IN
 THE SEDIMENT LAYER?

   Only a  few workers have investigated  this facet
 of  the problem  (Rudolfs, 1938; Baity,  1938; Fair
 et al., 1941). Rudolfs studied the progressive benthal
 oxygen demand  from sludge placed in carboys,  the
 supernatant being  drawn off  periodically and  re-
 placed by tapwater. Fair and his colleagues at Harvard
 used a modification of Baity's apparatus to simulate
 the  stream bottom  conditions.   Samples of  sludge
 or river mud were placed at the bottom of stoppered
 glass  carboys, and  a continuous, controlled flow of
 water was passed through the carboys; it was directed
 horizontally across the surface  of the deposit by a
 specially  designed  inlet and then flowed spirally to
 the water surface.  The reduction in dissolved oxygen
 was measured daily, and the rate of flow, which was
 also measured,  was adjusted to give a measurable
 difference between the dissolved-oxy^,sn concentration
 in the  inflowing  and outflowing water.  The average
 detention time in the carboys was 1  to 2 days.  The
 aerobic and anaerobic phases of benthal decomposition
 were isolated, for purposes of comparison, by stabi-
 lizing  separate  sediment samples under  essentially
 aerobic or anaerobic conditions.

   Baity (1938) had  found that  the oxygen demand of
 sludge deposits  was independent of  the dissolved-
 oxygen concentration  in the supernatant  water, and
 this  was  borne  out  by the observations of Fair
 et al (1941).  The most important conclusion of the
 Harvard investigators  is  that it is  not  the rate of
 diffusion of oxygen from  the supernatant water into
 the organic sediment that controls the rate of benthal
 oxygen demand,  but rather the rate of upward trans-
 port to the surface  of the sediment of the oxidizable
 substances produced by anaerobic action within  the
 deposits.   Fair et al. (1941) found that the maximum
 depth  for  this  upward diffusion was  about 10 cen-
 timeters.
   Parenthetically it  may be worth noting that some
 observations made on the Mersey estuary (Department
 of Scientific and Industrial Research, 1938) bear on
 this  matter.  The  main  deposits of  organic mud
 in the  estuary were in the Stanlow Bank,  which had
been stable over  many years.  Samples of mud were
taken at depths of up to 16-1/2 feet below the surface
of the  estuary bottom and were analyzed for organic
 matter.  It was possible,  from a study of the quin-
 quennial  survey  charts of the Mersey  Docks and
Harbour  Board, to  give approximate  dates to these
 various samples back to the year  1861.  The analyses
 showed "that the  amount  of  organic matter  in  the
 samples  of material deposited in earlier years  is
 approximately the same as in recent deposits con-
taining the same  amount of sand.  There  is thus  no
 evidence that the mud mixed with these samples  is
 significantly different in composition from the mud at
present found  on  the surface  at  Stanlow Bank."

   It seems clear, therefore, that the benthal oxygen
demand is  very much slower than the  aerobic oxygen
demand of the same material suspended in the flowing
water.    For example, the Royal  Commission in-
vestigators showed  that the oxygen demand of some
samples continued with comparatively little diminution
in rate  for  2  years (Royal Commission on Sewage
Disposal, 1913).   Fair  et al.  (1941)  applied their
mathematical formulation to these last-mentioned data
and showed that four sediment samples would take 15
to 25 years to become 99 percent stabilized.

   In  the Thomas estuary, which is deep and thus has
a small perimeter per unit volume, the oxygen uptake
at the surface of the mud represented only a com-
paratively small fraction of the total oxygen consumed
in the  estuary -  about 8 tons per day or about 1
percent, out  of an  estimated total  of  over 1,000
tons per day.  This oxygen uptake was measured in a
form of respirometer in the Water Pollution Research
Laboratory  and in a  larger in situ version of the
respirometer.  (Southgage, 1962, Ministry of Housing
etc., 1961).

   In addition to the work of Baity already mentioned,
the Water  Pollution Research  Laboratory (D.S.I.R.)
has made some laboratory and field determinations
of the  uptake  of  oxygen  by  mud deposits in the
Thames  estuary (see Table  1).  For the laboratory
determinations, an apparatus very similar to that of
Baity was used; for the field determination, a similar
technique was used by measuring the change of oxygen
concentration in a  stream  of water passed over 0.25
square foot of  mud enclosed in a special apparatus,
which  could  be lowered  to the  river bottom  Water
Pollution Research  1953.   Results are  shown in
Table  1.  The same  Laboratory, in the course of
its  studies   of  the oxygen  balance in freshwater
streams, has made an estimate of the  "mud  respi-
ration' in unpolluted reaches of the River Ivel (Water
Pollution Research 1961);  this result is also shown
in Table 1.
   For  many years the Freshwater Biological As-
socation has investigated  this matter  in connection
with its more extensive research on Lake Windermere.
Undisturbed cores of the  lake mud, obtained by means
of the Jenkin sampler, were tested in the laboratory
and gave typical  oxygen-uptake rates  of  0.2 of a
gram  of oxygen per square meter a  day.   At the
same  time, observation of the oxygen concentration
in the  hypolimnion,  during  the period  in  which
the lake water  was  thermally stratified,  showed
the total oxygen demand  of the  hypolimnion to be
0.4 of a gram of oxygen per  square  meter a day.
If  the  laboratory  figure of 0.2 of a gram a day for
the mud is accepted, it has to be assumed that there
are considerable transfers of dissolved oxygen from
one part of  the  hypolimnion to another.   No such
assumptions need be made if the mud uptake is, in fact,   ,
of the order  of 0.05 of a gram of oxygen per square
meter  a day (Mackereth,  1962).  More recently an
investigation  of Blelham Tarn has been put in hand.
In the  course of  this investigation,  large  plastic
cylinders have  been  sunk  in  the  lake  to  isolate
manageable volumes of the  lake water; some of these
cylinders are  open to  the bottom mud and others
are closed at the base.  The observations of oxygen
concentration, which have not so far been analyzed,
appear to bear  out Mackereth's belief that the oxygen
demand  of undisturbed bottom  muds is a good deal
less than is shown by laboratory estimations.
(Mackereth, 1962.)

-------
348
DETERMINATION OF SAFE LEVELS OF TOXICANTS
                                 Table 1.  BENTHAL OXYGEN UPTAKE
Nature of tests
Laboratory determinations
Sewage sludge 0.5 cm deep
1.0
1.5
2.0
4.0
Undisturbed cores from Lake
Windermere
Thames mud 1 day 7°C
15
25
5 days 7
15
25
Field observations
Windermere mud
Thames mud
30 min 16.5°C
19
20
River Ivel (unpolluted reach)

Oxygen uptake
rate,
g O2/m day

1.84
2.89
3.45
3.77
5.17
0.2

0.49
0.63
1.22
0.20
0.39
1.02

0.05a

0.88
0.98
0.88
2-5b
2.0-5.0
Reference

Baity (1938); Fair et al.
(1941)



Mackereth (1962)

Water Pollution
Research 1953





Mackereth (1962)

Water Pollution
Research 1953

Water Pollution
Research 1961
  aEstimated from the total hypolimnion rate of uptake of 0.4 g O2/m2 day - the theoretical value to give a
   coherent oxygen deficit  curve in the hypolimnion without assumi ng unlikely transfers of oxygen from one
   part of the hypolimnion to another.
  b,,
    In most cases it has been assumed that the mud respiration represents the difference between that of the
   total community and that of plants." Most respiration data were collected at night.
TO WHAT EXTENT  ARE BOTTOM MUDS RESUS-
PENDED IN THE FLOWING WATER?

   The Mersey Survey (Department of Scientific and In-
dustrial Research,  1938)  observed  that, in the upper
estuary of that river, mud banks that had reached a
height of  about 20 feet above Liverpool Datum were
relatively stable (hydraulically); we have already seen
that this  mud has collected for almost  a century
without becoming stabilized.  Mud deposits at a lower
level,  however, are  to  a great extent resuspended
on each tide (Water Pollution Research 1948).

   At the other extreme is the upper part of the Forth
estuary, from Stirling down to  Bo'ness, where  the
soft, almost  black mud is resuspended to a greater
or lesser degree by  each tide, aided by wind, where
the water shoals over banks. At high tide and at low
tide, slack water permits the  solids from all levels
to  settle   completely  in  the  deep-water  channel.
(Forth River Purification  Board,  1959).
   Tarzwell and Ganfin (1953) have shown that, on the
Great  Miami River,  the first high  water after  an
extended  period  of low water picks up sludge beds
and carries them farther downstream.  As a result
the zone  where  the  dissolved-oxygen  concentration
is critically low is extended.
                              In  nontidal  rivers,  it  goes without saying that
                           there is a downstream transfer of suspended matter.
                           In tidal estuaries this cannot be taken for granted.
                           It has been found in the Type estuary, for example,
                           that the net movement of bed load is upstream (Cassie
                           et al., 1960, 1962).  It is  finally removed by dredging.

                              We shall show,  in the next section, that the con-
                           tribution to oxygen depletion made by organic solids
                           in suspension is very much greater than that of the
                           stationary bottom  deposits.   The degree of resus-
                           pension  that  can take place in any particular  cir-
                           cumstances may, therefore, be of critical importance
                           to the oxygen concentration in a river.  This point is
                           particularly emphasized  in the Thomas estuary report
                           (Ministry  of Housing and Local Government,  1961).

                              Resuspension of bottom  deposits is not, however,
                           the whole story: bottom deposits are, for the time that
                           they remain on the bottom, in effect oxygen-demand
                           removed;  any factors,  therefore, that affect  sedi-
                           mentation  in streams may  well be  relevant.  It has
                           been estimated  that an appreciable fraction, possibly
                           about a fifth, of the  oxidizable matter (both  soluble
                           and insoluble) entering the Thames estuary is removed
                           by deposition and dredging (Ministry of Housing and
                           Local Government, 1961).  Three matters investigated

-------
                   The Contribution of Bottom Muds to the Depletion of Oxygen in Rivers
                                               349
by the Water Pollution Research Laboratory (D.S.I.R.)
may be of interest in this matter.

   In the late 1940's  the  Laboratory  investigated,
for the Mersey Docks  and Harbour Board, the effect
of the discharge to the Mersey  estuary of an alkaline
sludge. This sludge, referred to as distiller blow-off
(or DBO) sludge, arose from the manufacture of sodium
carbonate by the Solvay ammonia pro cess. It contains,
in suspension, caicium carbonate, calcium sulphate,
and  calcium hydroxide with impurities from lime-
stone and coke, and, in solution, high concentrations of
calcium and sodium chloride, and small concentrations
of dissolved calcium hydroxide  and calcium sulphate.
Laboratory  tests showed that when sufficient sludge
was added to a suspension of estuarine mud in non-
saline  estuary  water  to  increase the  suspended
solids to  50 ppm, the settling rate was greater than
that of a mud suspension alone with the same sus-
pended-solids  concentration.   Where, however,  the
sludge was  treated by  carbonation before discharge,
the settling rate was reduced.  Further, the Mersey
mud with carbonated sludge was  less  easily eroded
than  the  mud alone  or than the mud with untreated
sludge. (Water Pollution Research 1948.)

   In connection with the  investigation of the River
Ivel(Water Pollution Research 1961) already mentioned,
it was  shown  that  a sewage effluent  prevented  the
deposition on snail shells or glass plates of calcium
carbonate from the  river water, which had a total
hardness  of about  290  ppm  (as CaCOs).  The same
sequestering effect was observed in the laboratory
with  carboxy methyl-cellulose.  (Water  Pollution Re-
search 1959).

   "It  has been  reliably  reported  that the  concen-
tration  of  suspended  matter  in the  water of  the
Thames  Estuary has visibly increased during  the
last 10 years,  and  it is suggested that the increased
use of synthetic detergents during this time may be
responsible."    (Water  Pollution  Research  1960).
To  test  this  hypothesis  in  the laboratory, various
concentrations  of  detergent-free  river  mud were
suspended in a mixture  of equal  volumes of detergent-
free  sea  water and  tapwater.   Settling tests were
run in pairs, with  one  of each  pair  carrying a con-
centration of 1 ppm of a straight-chain alkylbenzene-
sulphonate.   "These  results show that  the effect of
1  ppm  surface-active  matter  is to  decrease  the
rate of settling of the mud for any given mud con-
centration.  In one  experiment in which the detergent
concentration  was  increased tenfold,  the effect on
solids in suspension  was roughly doubled."   (Water
Pollution Research  1960.)

   The Mersey Survey  showed  that there was some
interaction  between  sewage  solids and suspended
solids but that the  net  effect depended on the degree
of mechanical flocculation and  stirring (Department
of Scientific and Industrial Research, 1938).

   A  rather  higher  velocity  of flow is  required to
scour bottom deposits than is necessary to keep  the
material in suspension once it has  been scoured.
It goes without saying that the scour velocity de-
pends on the nature, size, and specific gravity of  the
 particles to be  lifted,  and on the Darcy-Weisbach
 friction factor.  These criteria are used in the design
 of  grit  channels  for sewage treatment plants,  and
 Velz (1949) has analyzed  grit channel experience in
 an  attempt to define scour  velocities in streams.
 He  suggests that, to scour digested organic  matter
 with a 1-millimeter  particle diameter,  a velocity of
 1.3 feet  per second would be necessary; he regards
 this as an extreme case.   Fresh organic sludge  can
 be  resuspended  at velocities of  0.6 to  1.0 foot  per
 second.

   Velz  had an unusual opportunity to test his theory
 in  studies on  the Kalamazoo  River made- for  the
 National  Council  for  Stream  Improvement.   Two
 reaches  with bottom deposit  were separated by an
 intervening clean  stretch.   An examination  of  the
 river  hydraulics  showed  that  the channel velocity
 in  the  clean  stretch would not drop to 0.6 foot  per
 second until the flow dropped to 130 cubic feet  per
 second.  Hydrological analysis indicated that a runoff
 as  low  as  this had  a probability of only 5 percent.
 Both theory and observation demonstrated, therefore,
 that sludge deposit occurred only quite rarely.   In
 the upper reach where deposits occurred, a channel
 velocity  of 0.6 foot per second was attained when flow
 dropped  to  700 cubic feet per second, a  frequent
 occurrence.  The  reach was examined at a time when
 the runoff was 835 cubic feet per second and showed
 the  presence  of organic deposits without large  ac-
 cumulations.   In the lower sediment stretch, large
 accumulations  of stable organic material were found.
 For this stretch, channel velocities of over 0.6 foot
 per second were reached only when the flow exceeded
 1,500 cubic  feet  per second, and  flows of less than
 this for long  periods   gave  rise to the extensive
 accumulations noticed.  The lower reach was scoured
 only during freshets or floods.

   It is dangerous to extrapolate from a single  series
 of tests, but we  may conclude from  Velz' work  that
 it is likely  that channel velocities of 0.6 to 1.3 feet
 per  second will  be  sufficient to  resuspend organic
 bottom deposits in streams.

 DO  RESUSPENDED  BOTTOM  MUDS  EXERT  AN
 OXYGEN DEMAND?

   There can  be   no doubt  that  the  answer  to this
 question is an unequivocal  affirmative.  This is borne
 out by  such qualitative observations as that of Spencer
 (1962)  who, in the 1930's,  noticed that disturbance of
 river flow during constructional alterations to a bridge
^stirred up bottom deposits and caused a  very marked
 reduction in the dissolved-oxygen  concentration,  re-
 sulting in fish mortalities.  From the time of the Royal
 Commission onwards careful laboratory measure-
 ments  have been  made to  assess the contribution
 of  suspended  organic  solids to  oxygen depletion;
 these we shall here examine.

   "Observations  have shown that  solids . . . while in
 suspension, account. . . for a considerable proportion
 of the  total oxygen uptake" in the Thames (Ministry
 of Housing and  Local Government 1961).  It has  not
 yet proved  possible  to  trace,  with any  degree  of
 exactitude,  the  movement of sludge deposits  in  the

-------
350
DETERMINATION OF SAFE LEVELS OF TOXICANTS
Thames, but it has been observed that  "the change
in position of the deposits with varying  fresh-water
flow affects  considerably the concentration of sus-
pended solids in estuary water in their neighbourhood,
and this in turn influences the rate at which oxygen
is taken up in different parts of the estuary."  (Water
Pollution Research 1952.)
   First, however, it may be of value to record some
analyses of bottom deposits so that we may assess
their possible oxygen demand; such analyses are shown
in Table 2.  Although there was a very wide variation
among the very large number of Mersey mud samples,
the general  carbon:nitrogen   ratio was about 10.
                              The  comparatively few  data given in Table 3 are
                           so  diverse  that  it is difficult, if  not dangerous, to
                           draw any but  general conclusions.  Two conclusions,
                           however,  clearly suggest themselves.  The first is
                           that the potential oxygen demand of bottom deposits
                           is  very considerable  if these deposits become re-
                           suspended.  A closer study of the  Connecticut River
                           data suggests that, as may be expected, this demand
                           (even when  measured in terms of the initial volatile
                           solids) is reduced as the deposits become "stabilized."
                           Stabilization,  in  this sense,  probably  includes the
                           results  of two effects: Hydraulic scour, which would
                           tend to  reduce organic matter more than inorganic,
                           and dissimilation, which would assist this differential
                           organic breakdown.
                               Table 2. MUD ANALYSES (based on dry weight)
Material
Thames mud
South San Francisco
Bay:
Reference
Moisture,
%
51,0



Dumbarton Bridge -
Calaveras Pt.
Calaveras Pt. -
Alviso Slough
Coyote Creek
Connecticut River
deposits
Domestic sewage
sludge
Sludge deposit
River mud
(New England)
English river muds
Anker
Avon
S. Delph
Canal
Intertidal deposits,




Volatile
solids,
%









Organic
carbon,
%
1.92


1.13

1.20

1.43
1.54
45 to 97 2.50 to 14.4


91.5
88.8
82.6


76.3


83
13.9
24.2


15.3








75 to 83 11. 7 to 17.1
46.7
60.3
10.8 to
upper Mersey estuary 71.6
11.0
11.2
1.2 to
21.4


0.00 to
4.34
Kjeldahl
nitrogen,
%
0.214











3.75
0.62
1.02


4.4 a
4.1-5.1 a
1.3 a
2.4 a
0.01
0.53
O:N
ratio
9.0




















Sulphide
(as S),
%
0.160


0.030

0.037

0.041
0.094












0.6 to Oto
46.5) 0.18
Reference
23
8







12,16


1
6
6


13



5

         a Total nitrogen (averages) as
            • of volatile matter in dried mud.
                      t
   The  oxygen demands of  sludge  and mud solids
when stabilized aerobically are collected in Table 3.
For  comparison  it  is  worth noting that the initial
benthal oxygen demands given in Table 1 for the sewage
sludge  (Baity, 1938; Fair et al., 1941) range from
1.83  to  5.17 grams  of oxygen  per  kilogram  of
volatile solids per day.
                              Although it is,  perhaps, not strictly  relevant to
                           an  answer to our question, it is interesting to note
                           that the Royal Commission on Sewage Disposal (1913)
                           made careful estimates of the  5-day  BOD (at 18°C)
                           of a number of settled sewages  and sewage effluents,
                           both  with their  suspended  solids and after  paper

-------
             The Contribution of Bottom Muds to the Depletion of Oxygen in Rivers
351
                    Table 3.  OXYGEN DEMAND OF SUSPENDED SOLIDS
Material
Connecticut River deposits a 1


2


3


4


5


6


7


8


9


10


English River muds - Anker (304)

Avon (306)

Avon (308)

Avon (309)

Chelmer (123 k)

Canal at Berkhamsted (128 k)
Sewage sludge
Sludge deposit
New England river mud
Thames mud from dredger hopper
Barking reach
Gravesend reach
Tidal basin, Tilbury
Royal Docks
Tilbury Docks
Dry
solids,
%
22.3


40.9


11.3


2.6


7.3


41.3


41.6


54.7


22.0


33.7


23.7

24.6

16.6

22.2

53.3

39.7
8.5
11.25
17.4

43.1
33.5
25.5
18.0
24.0
Volatile
solids,
% (DS)
3.53


2.50


14.4


11.7


6.1


6.73


6.08


2.97


9.68


4.33


15.3

11.7

17.1

12.8

11.0

11.2
83.0
13.85
24.2






Oxygen demand at 20° C
Time,
days
4
6
10
4
6
10
4
6
10
4
6
10
4
6
10
4
6
10
4
6
10
4
6
10
4
6
10
4
6
10
5
650
6
650
5
650
6
650
5
650
650
5
5
5

5
5
5
5
5
Demand,
g O2 per
kg(VS)
46.7
57.8
81.7
56.4
75.2
123.5
84.2
115.8
179.7
93.9
131.8
198.2
62.0
68.0
90.8
24.1
31.5
44.2
28.1
35.2
49.0
34.7
42.8
57.3
80.9
116.8
155.5
30.0
39.4
53.2
32.5
205.0 c
16.1
144.0 c
86.7
324.0 c
110.2
248.0 c
36.4
174.0 c
128.0 c
173.0
331.0
47.7

v.*
8.7 d
9.5d
15.6 d
8.1 d
Reference
12, 16





























13










1,6
6
6

26




a Oxygen demands determined in a Warburg respirometer.
b BOD measured at 18°C.
c Oxygen uptake measured in Adeney's respirometer (in still water except for sample 123 K).
d In g Oo/kg dry solids.

-------
352
                            DETERMINATION OF SAFE LEVELS OF TOXICANTS
filtration; it was found that paper filtration reduced
the BOD about one-half.  (Parenthetically it is worth
remembering  here that,  for this  reason,  the Royal
Commission's  BOD  standard includes the BOD  of
any suspended matter.)

   Table 3 does not include  results from the Survey
of the upper  estuary  of the Forth because these are
not given in a form that can be immediately translated
into the form of this Table. Samples of mud, exposed
at low  tide,  were collected  from four points in the
estuary.  Sufficient amounts  of  each mudweremixed
with 6  liters of clean sea water to give a mixture
containing  1  percent  dry  matter;  each mixture was
used to  fill  two sets of  six 12-ounce bottles.  The
suspension in  the first bottle  of  each series was
immediately  precipitated  with alum and  ammonia,
and the supernatant was drawn  off for the measure-
ment  of dissolved oxygen.   The other five pairs of
bottles  in  each series were  incubated at 20 °C; one
set of  each  series was  allowed to  settle  and the
other set  of each series  was shaken  twice daily.
Each  day  a  pair  (1  shaken, 1 quiescent)  of  each
series was withdrawn, treated  with chemicals, and
the supernatant drawn off for dissolved-oxygen de-
termination.    The results  are given in Table  4.
(Collett, 1961).
CAN WE LIMIT BOTTOM DEPOSITS  BY IMPOSING
SUSPENDED-SOLIDS STANDARDS ON EFFLUENTS?

   In assaying  answers to the first four questions we
have been able to look to  factual evidence produced
by  field observation  and laboratory investigation;
we  now  come  to the realm  of opinion.  It is in this
region  that  the  greatest potentiality  for  sincere
disagreement arises,  and it is  here, perhaps, that
the most valuable discussion can arise.  The author
will concentrate  on the British viewpoint, confident
that many in his audience will be particularly qualified
to put the American view.

   There will be little argument that  there  must be
some  control  of the  amount of suspended solids
discharged to  a  stream  or  lake.  Herbert (1961),
for example, has shown that 1,000 ppm of china clay
(an inert solid) considerably reduced  the population
of brown trout in Cornish streams, possibly owing to
destruction of bottom fauna.  In addition, a substantial
proportion  of the trout in  the more turbid waters
"showed a  thickening and coarsening of the epithelial
cells of their gills - a condition which has been ob-
served in trout kept in suspensions  of china  clay and
other inert  material  in  the laboratory,  but  which
was not found in control fish kept in clean water"
                  Table 4.  OXYGEN DEMAND OF RIVER FORTH MUDS (COLLETT, 1961)
Location
Dry matter, %
Organic matter, % (DS)
Oxygen concentration,
ppm
Initial
1st day
2nd day
3rd day
4th day
5th day
Seawater
only



8.02
7.98
7.94
7.74
7.67
7.61
Ladysneuk
52.3
10.8
Sha Qub
7.72 7.72
5.52 5.88
3.97 4.86
2.97 3.65
1.59 3.45
1.03 2.20
Haugh C
53.9
10.5
Sh Qu
6.06 6.28
2.68 3.88
1.46 3.48
1.05 3.26
0.10 2.63
0.07 1.02
imbus Harbour
41.5
18.0
Sh Qu
4.53 4.64
0.47 2.86
0.06 2.28
Nil 1.64
Nil 1.26
Nil 0.54
Kincardine
42.3
17.2
Sh Qu
4.45 4.08
Nil 2.08
Nil 1.38
Nil 1.47
Nil 0.85
Nil 1.16
            Shaken.
            Quiescent.
   It will readily be  seen from these  results that
the  continual disturbance of  the  mud  produces a
substantial demand  on the dissolved oxygen in the
water of the  upper estuary.   The results, however,
are not quite satisfactory in two respects: There was
a very large oxygen uptake on  first  mixing the mud
with the clean sea water, and the mud in the quiescent
samples  took rather  long to  settle initially.  The
test method  was modified slightly in an attempt to
overcome these  difficulties,  but in  all cases  the
oxygen uptake from  the  shaken samples was greater
than that from the quiescent samples. (Collett, 1961.)
(Herbert, 1961).  Even 60 ppm of such inert suspended
matter  may affect  spawning grounds but is unlikely
to be harmful otherwise.

   It is clear that  bottom  deposits will be produced,
even in fast-flowing streams,  by suspended-solids
concentrations  as  great as we have just been dis-
cussing.  Quite apart from possible contribution to
oxygen demand, therefore,  it is clear that suspended-
solids standards must be set  up to prevent  such
deposits.   Such standards  will normally  result, after
the appropriate dilution in the receiving water, in a

-------
                   The Contribution of Bottom Muds to the Depletion of Oxygen in Rivers
                                               353
relatively  nonturbid  stream, and it is the next stage
of control that ought to concern us.

   Even an effluent free from any  suspended solids
would,  if  it  contained  organic  matter, produce, by
bacterial  synthesis,  some  suspended  solids.   So,
although reasonably drawn suspended-solids standards
can  do  much to  limit bottom deposits, they cannot
altogether  eliminate them; for this we should require
the  complete removal  from an effluent of organic
matter  as  well. It is probably unrealistic, therefore,
to consider suspended-solids standards in isolation.

WHAT  RATIONAL CRITERIA  CAN WE APPLY TO
SUCH STANDARDS?

   As Van Beneden  (1957)  emphasizes, we are too
much  concerned  in our consideration of receiving
waters   with  their self-purification  capacity.   As
he says, we tend to take account only of the supernatant
water, and we are hypnotized by its capacity for taking
up  oxygen from the atmosphere, forgetting that the
body of water  is acting also as a settling tank. In
this  review,  we   have been  concentrating  on this
latter aspect.

   The  JRoyal Commission  (1913)  investigators, as
we  ha've seen,  frequently  emphasized the possible
deleterious effects of  bottom deposits and certainly
took account of  suspended solids in proposing their
famous  standards, which may be  expressed in this
form *:

   1. Dry-weather dilution of effluent by river 500:1
      or more - crude sewage may be discharged after
      screening  and grit removal;
   2. dry-weather dilution between  300:1 and 500:1  -
      sewage  to be settled  to give  suspended-solids
      concentration of  less than 150 ppm;
   3. dry-weather dilution between  150:1 and 300:1  -
      sewage  to be chemically coagulated  and settled
      to  give  suspended-solids  concentration of less
      than 60 ppm;
   4. dry-weather  dilution  between  8:1 and 150:1  -
      sewage  to  be given full treatment to reduce
      suspended-solids  concentration  to  less  than
      30 ppm and to  give  a 5-day (18° C) BOD of
      less  than  20 ppm, including the BOD of any
      suspended solids;
   5. dry-weather  dilution  less than  8:1  - specially
      stringent standards called for.

   The Appendix to the  Eighth Report goes on: "The
quality  of  the diluting water would also  have to be
specified.   Probably  this would be  fixed  at  about
[2 ppm]  of dissolved  oxygen taken up from water in
5 days, no less dilution being allowed with water of
greater purity.  A water taking up [4 ppm] of dissolved
oxygen in 5  days could not be considered as giving
any  dilution,  since  it  is,  itself,  on the  verge of
causing  nuisance; while a water taking up  [3 ppm]
must also  be  looked upon as of very doubtful quality
as a diluent for unpurified sewage or sewage liquor.*
(Royal Commission on Sewage Disposal, 1913.)
   These recommended standards were certainly based
on the results of wide observation of a large number
of English  streams.   It  is  possible, nevertheless,
that these observations  overestimated the effective-
ness  of the mixing that occurs below a sewer outfall.
In the half century since the publication of this famous
Appendix, the dry-weather flows of  many important
English rivers have been reduced by increased water
abstraction and by improved land drainage, which has
seriously reduced groundwater  storage.   It is not
unlikely,  therefore, that  some  important receiving
waters have BOD's of more than 2 ppm and, therefore,
give  less  effective dilution.   Probably  the  Royal
Commission's  20/30  standard  should now demand
dilutions of no less than  15 or 20:1.

   With these dilutions  available, the 20/30 standard
should be adequate to prevent excessive buildup of
sludge deposits, except immediately below the  out-
fall.   Where the velocity of  flow, however, is very
low, or where the water is quite still, more stringent
standards are likely to be necessary.

   Some  of the rivers around London are in a peculiarly
serious position: many of them are sources of potable
water, their flows  are very low, and they  receive
drainage  from  large  concentrations of  population.
All  these  factors  call  for  much  more stringent
effluent standards. The Rye Meads sewage treatment
works, for  example, has to achieve a 10/10 standard
in winter and a  5/5 standard in summer. This calls
not only  for the highest standards of operation but
also for tertiary treatment.

   Indeed, there is a  tendency for the English River
Boards  to  demand  that  the  suspended-solids con-
centration of sewage effluents be reduced substantially
below 30  ppm.  Some improvement  can be achieved
by increasing the capacity of the final settling tanks,
but,  aside from the cost, this is usually  undesirable
for   settling following  activated-sludge  treatment.
In Britain today a significant reduction in suspended
solids, where  it  is called for, is usually obtained
by microstraining or rapid sand filtration.

                   CONCLUSION

   This  review is intended to stimulate discussion,
not to give an ex-cathedra pronouncement that stifles
all  discussion.   Questions have been posed  on the
extent to which bottom deposits contribute to the oxygen
demand in streams, and some  observations have been
culled from the literature to assist in answering these
questions.

   Most  authorities concerned  with the  control  of
river pollution  have,  by  implication, answered the
various  questions,  but the  author  doubts whether
the  answers are, in most cases, any more than the
codification of  habit and prejudice. Practical action
has,   in this field,  been  based  on inadequate field
observation or  not entirely relevant  laboratory in-
vestigation.  A  good deal  more work is required on
the  in situ measurement of oxygen uptake by bottom
* In fact, standards nos. 1 to 3 were expressed the other way round, Le.,fhe minimum dry weather flow dilutions were given for the
  specified treatments, which were expected to give the suspended-solids concentrations laid down.

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   354
DETERMINATION OF SAFE LEVELS OF TOXICANTS
   muds.   In  addition a  thorough investigation of the
   fate of  suspended  matter discharged to, or produced
   in, receiving waters is urgently needed.

   ACKNOWLEDGEMENTS

      In closing I must express my gratitude to Mr. M.
   Lovett,  Chief  Inspector of the Yorkshire Ouse River
   Board,  Mr.  F.J.H. Mackereth,  of  the Freshwater
                           Biological Association, Dr. B. A. Southgage, Director
                           of Water Pollution Research, and to Mr. J. H. Spencer,
                           River Inspector of the Clyde River Purification Board,
                           for so kindly dealing with my importunate questioning;
                           to  Mr.  John  Gay,  Chadwick  Bronze  Medallist  in
                           Public  Health  Engineering  (University of  Durham),
                           for very great assistance with the search of American
                           literature; and to  my secretary,  Mrs. Thompson,
                           for all her assistance.
                                                REFERENCES
 1. Baity,  H. G.  (1938) Studies  of sewage sludge.  Sew.
  ' Wks. J.,  10, 539-568.

 2. Cassie,  W.F., Miller, E., Allen, J., and Hall,  D.G.
   (1960)  Hydraulic and sediment survey of the estuary
   of the  River Tyne.  Report for the year July 1959 -
   June 1960. Bulletin No. 20, Dept. of Civil Engineering,
   King's College, Newcastle.


 3. Cassie, W.F., Allen, J., and Hall, D.G. (1962) Hydraulic
   and sediment survey  of  the estuary of the River
   Tyne.   Report for  the year July 1960 - June 1961.
   Bulletin  No. 24,  Dept. of Civil Engineering, King's
   College,  Newcastle (in press).

 4. Collett,  W.F. (1961) A preliminary investigation of
   the pollution of the  upper Forth estuary. J. & Proc.
   Inst. Sewage Purif., Part 5, 1961, 418-433.

 5. Department of Scientific and Industrial Research (1938)
   Estuary  of the River Mersey: the  effect of the dis-
   charge of crude sewage into the estuary of the River
   Mersey  on  the amount and hardness  of the deposit
   in the  estuary.  Water Pollution Research Technical
   Paper No. 7. H.M. Stationery Office, London.

 6. Fair, G.M., Moore,  E.W., and Thomas, H.A. (1941)
   The natural purification of river muds and pollutional
   sediments.   Sew. Wks.  J., 13, 270-307,  756-779.

 7. Forth  River  Purification Board  (1959) Results of
   Preliminary  Survey  of the Tidal Waters of the River
   Forth. The Board, Stirling.

 8. Harris,  H.S., Feuerstein, D.L., and  Parson,  E.A.
   (1961)    A Pilot  Study of Physical, Chemical, and
   Biological Characteristics of Waters and Sediments
   of  South San Francisco  Bay  (South  of Dumbarton
   Bridge).   San. Eng. Res. Lab., University of Cali-
   fornia, Berkeley.


 9. Herbert,  D.W.M.  (1961)  Fresh-water fisheries and
   pollution control.  Proc. Soc.  Water Treat. Exam.,
   10, 135-161.

10. Mackereth, F.J.H. (1962)  Personal communication.

11. Ministry  of  Housing and  Local  Government (1961)
   Pollution of  the  Tidal  Thames.    H.M. Stationery
   Office, London.

12.Oldaker,  W.H. (1951)  Bottom deposits and their re-
   lation to  pollution in the Connecticut River.  Sanitalk,
   5, No. 3,  8-11.
                        13. Royal Commission on Sewage Disposal (1913) Appendix
                           to the Eighth Report. H.M. Stationery Office, London.

                        14. Ruchhoft, C.C., and Moore, W.A,, (1940) Determination
                           of biochemical oxygen  demand  and dissolved oxygen
                           of  river  mud suspensions.   Industr.  Eng.  Chem.,
                           Anal. Ed., 12, 711-714.

                        15. Rudolfs, William (1938) Stabilization of sewage sludge
                           banks.  Industr. Eng.  Chem., 30, 337-340.

                        16. Sanitary  Engineering  Research Committee, Stream
                           Pollution Section. (1958) Bottom deposits in a river
                           and their potential effects on dissolved oxygen con-
                           centrations.    Proc.  Amer. Soc.  Civ.  Engrs.  84,
                           SA5, 1779/1-7.

                        17. Southgage, B.A. (1962) Personal communication.

                        18. Spencer, J.H. (1962) Personal communication.

                        19. Tarzwell, C.M.,  and  Gaufin, A.R.  (1953) Some im-
                           portant biological effects of pollution often disregarded
                           in stream surveys.   Proc. 8th Industr. Waste Conf.,
                           Purdue Univ.

                        20. Van  Beneden,^ G. (1957) Les effets de la  coulee de
                           boue et les depots de fond sur 1'e'quilibre biologique
                           des cours d'eau recepteurs.  Bui. Trimestr. Centre
                           Beige d'Etude et de  Documentation des  Eaux.  36,
                           99-104.

                        21. Velz, C.J. (1949) Factors influencing self-purification
                           and their relation to pollution abatement.  II: Sludge
                           deposits  and  drought probabilities.   Sew. Wks J.,
                           21, 309-319.
                        22. Water  Pollution  Research  1948.   H.M.  Stationery
                           Office,  London.
                        23. Water  Pollution  Research  1949.   H.M.  Stationery
                           Office,  London.

                        24. Water  Pollution  Research  1952.   H.M.  Stationery
                           Office,  London.
                        25. Water  Pollution  Research  1953.   H.M.  Stationery
                           Office,  London.

                        26. Water  Pollution  Research  1954.   H.M.  Stationery
                           Office,  London.
                        27. Water  Pollution  Research  1959.   H.M.  Stationery
                           Office,  London.
                        28. Water  Pollution  Research  1960.   H.M.  Stationery
                           Office,  London.
                        29. Water  Pollution  Research  1961.   H.M.  Stationery
                           Office,  London.

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                       Accumulation of Cesium-137 Through the Aquatic Food Web
                                             355
                 ACCUMULATION OF CESIUM-137 THROUGH THE AQUATIC FOOD WEB

                                        Robert C. Pendleton *
   The evaluation  of the hazard to man of cesium-
137 from fallout has been based on uptake from ter-
restrial food  chains (Anderson  et al.f 1957; Miller
and Marinelli, 1956; Langham and Anderson, 1957;
Marinelli and  Rose, 1957; Labby, 1957; Langham and
Anderson, 1959).  It seems appropriate, therefore, to
show the difference in bioaccumulation of this isotope
in an aquatic environment and relate these data to
the food web through which cesium may be accumulated
by man. If, as Anderson and Gustafson (1962) report,
cesium-137  may contribute as great a dose to human
bone as strontium-90, ecological differences affecting
the accumulation of  cesium assume  a greater im-
portance than formerly was thought.

   This  report, a  followup to  a previous report
(Pendleton and Hanson, 1958), contains results obtained
in a study of the absorption and transfer of cesium-137
by  organisms, water,  and sediments  in  a small
aquatic communtiy.  Results of laboratory experiments
  Table 1.  ACCUMULATION OF Cs 137 BY AQUATIC PLANTS GROWN IN A SIMULATED FARM POND
Organism
Algae
1. Rhizoclonium crassipelitum West and West
2. Spirogyra crassa Kuetzing
3. Mixed phytoplankton
Submerged seed plants
1. Water weed (Elodea canadensis Michx.)
2. Coontail (Ceratophyllum demersum L.)
3. Sago pondweed (Potomogeion pectinatus L.)
Floating plants
1. Water fern (Azolla filicutoides Lam.)
2. Duck weed (Lemna minor L.)
Emergent seed plants
1. American bullrush (Scirpus americanus Pers.)
Culms
Seeds
2. Hardstem bullrush (Scirpus acutus Muhl.)
Culms
Seeds
3. Broadleaf cattail (Typha latifolia L.)
Leaves
Seeds
Marsh plants
Concentration

900
100
1,200

300
200
600

200
400


50
60

50
200

200
100


to
to
to

to
to
to

to
to


to
to

to
to

to
to

factors a

4,000 b
400
14,000 c

1,000
1,500
1,000

300
600


100
300

100
400

700
700

                    1. Green bristle grass (Chaetochloa viridis Scribn.)


2.


3.


Leaves 50
Seeds
Spotted persicaria (Polygonum persicaria L.)
Leaves
Seeds
Marsh marigold (Bidens tripartite L.)
Leaves
Seeds
80

200
400

100
300
to
to

to
to



250
270

700




     a Concentration factor = Cs 137/g organism
                             Cs 137/ml water
     13 Contamination levels of Cs 137 in organisms varied with seasons and other environmental changes.
       The ranges of values shown are mean values for minimum and maximum uptake conditions. Single
       values indicate organisms sampled during only one season.
     c A higher concentration factor for plankton (25,000) was observed on one sampling period.
*  Res. Assoc Prof , Experimental Biol Head, Dept. Rad. Safety, Univ. Utah, Salt Lake City, Utah.

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356
                            DETERMINATION OF SAFE LEVELS OF TOXICANTS
have been combined with reports of other workers
to illustrate the effect of aquatic conditions  on the
accumulation of  cesium-137  in  the  foods of man.
DIFFERENTIAL  AVAILABILITY  OF CESIUM TO
AQUATIC AND TERRESTRIAL PLANTS.

   Uptake of cesium-137 by terrestrial plants is low
(Rediske and Hungate, 1955;  Klechkovsky, 1957) be-
cause, upon entering most soils,  cesium is quickly
and  firmly  bound to the soil surfaces (Ch.-istenson
et al., 1958; Neel et al.,  1953; Nishita, Kowalewsky,
and  Larson, 1954)  and is,  thereafter, only slightly
available  to plants.  Consequently, terrestrial plants
have  little  chance to accumulate  the isotope from
soil.  In contrast, aquatic plants exposed to cesium-137
in an  aquatic  ecosystem accumulated at least 500
times as much of the isotope as plants grown in soils,
which  shows a large difference in the availability of
cesium-137 to aquatic food webs  as compared with
terrestrial food webs (Pendleton and  Hanson, 1958).
The  high  uptake values reported  for  some  algae
(Williams  and  Swanson, 1958) and  for fish flesh
(Knobf, 1951;Krumholz,   1956) agree with  this inter-
pretation.  Klechkovsky (1957) reported amuchhigher
uptake of this istope  by cereal plants grown in nutrient
culture than by  plants grown in soil.   The data in
Table  1, which were obtained from plants grown in
an aquatic community, indicate that if cesium can reach
the root or other plant surface through a water contin-
uum, it is taken up readily or adsorbed upon the plant
surface, but at different levels according to species.
Strong  differences  that  correlate  with ecological
changes are also apparent.

   The high contamination levels in aquatic plants,
particularly submerged species, are thought to result
from rapid sorption of cesium-137 before  the ions can
be  fixed  by  other   surfaces  such  as  mud.   This
rapid sorption was shown by the rate at which algae
accumulated the isotope after the first "spiking" of the
pond.  Floating rafts of Rhizoclonium took up cesium-
137  so rapidly that 10 minutes  after  the isotope
was  added, survey instruments showed the rafts could
be defined as radioactive "islands." No comparable
means has been shown for the accumulation of cesium
by terrestrial plants with the exception of a limited
amount of foliar absorption and entrapment of parti-
cles on aerial surfaces.
   Many  emergent plants  inhabiting saturated soil
or shallow water  develop root systems  at or  above
the soil  level.   Such superficial  root  systems lie
in an area from which cesium ions may be readily
obtained.  Large increases in uptake of cesium-137
by plants  grown in shallow water and saturated soil
as compared with upland habitats have been demon-
strated  (Pendleton and  Uhler,  1960; Tensho,  Yeh,
and Mitsui, 1961).

   Thus, the  root ecology of  wetlands  contributes
to increased availability of cesium-137 to aquatic food
webs by adding  higher root absorption to the amount
from  direct  fallout upon  the  plant  surfaces.  The
evidence presented indicates that, given equal con-
tamination, the availability of cesium-137 is markedly
greater from aquatic situations than from the ter-
restrial environment. Further evidence that accessi-
bility of the  ions is  important appears in Table 2
where the difference  in  accumulation of cesium-137
by plants rooted  in  sand and gravel as contrasted
with those grown in mud is shown.
AVAILABILITY OF  CESIUM TO AQUATIC ANIMALS

   Because  of  the increased availability of cesium to
aquatic plants, aquatic  animals also show high con-
centration factors for this element (Table 3).

   In the concentrations shown by  different trophic
levels,  another factor influencing the accumulation of
cesium is  illustrated.   This factor is of sufficient
importance  to  warrant  examination of the evidence
supporting  it,  and is also an attempt to explain the
biological reasons for its occurrence.
ACCUMULATION OF CESIUM-137  ACCORDING TO
TROPHIC LEVELS

   With  the exceptions of  some  species of algae
that had  higher  values,  insect  predators that  had
lower  values,  and several  species that  had some
seasonal high values, contamination levels  of cesium-
137 increased directly with the trophic level (Tables 1
and 3).  Trophic-level dependence  for cesium-137
accumulation has been reported before  (Pendleton
and Hanson, 1958; Pendleton, 1959), and field  studies
      Table 2.  INFLUENCE OF SUBSTRATE ON ACCUMULATION OF Cs
                                                                       137
                   BY EMERGENT PLANTS
                                                   Concentration factors
Organism

Cattail

Hardstem Bullrush
Grown in mud
Leaves
70
Culms
50
Roots
170

40
Seeds
100

90
Grown in sand and gravel
Leaves
250
Culms
120
Roots
250

450
Seeds
100

300

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                       Accumulation of Cesium-137 Through the Aquatic Food Web
                                                                                                    357
        Table 3.  ACCUMULATION OF Cs 137 BY ANIMALS GROWN IN A SIMULATED FARM POND
                     Organism
Herbivorous animals

    1. Water snail (Radix japonica Jay)
        Entire
    2. Bullfrog tadpole (Rena catesbeiana Shaw)
        Entire
        Gut and contents
        Flesh
    3, Spadefoot toad tadpole (Scaphiopus hammondi
        intermontanus)
        Entire

Carnivorous animals

    1. Damselfly nymphs  (Ischnura sp.)
        Entire
    2. Dragonfly nymphs (Erythemis callocata Hag.)
        Entire
    3. Pumpkinseed  (Lepomis gibbosus L.)
        Adult, entire
        Muscle
    4. White crappie (Pomoxis annularis Raf.)
        Entire
    5. Bluegill (Lepomis m, machrochirus  Raf.)
        Entire
    6. Bullfrog (Rana catesbeiana Shaw)
        Muscle

Omnivorous animals

    1. Carp (Cyprinus carpio L.)
        Entire
        Muscle
    2. Water shrimp (Hyalella aztecaSaus.)
        Entire
              Concentration factor
                                                                          600

                                                                        2,600
                                                                        4,500
                                                                        1,000
                                                                        6,000




                                                                        500

                                                                        400

                                                                      2,000
                                                                      7,000

                                                                      2,000

                                                                      6,500

                                                                      8,000
                        to

                        to
800 a

800
                        to  7,500
                        to 11,000
                        to 11,000
                                                                       1,000
                                                                       2,000    to  3,000

                                                                       1,400    to 11,000
        a Ranges of values are means for minimum and maximum uptake. Variations stem from
          seasonal and other ecologic differences. Single values indicate sampling during one
          season only.
have shown  trophic level  effects on accumulation of
cesium-137 through the situation was not recognized
(Hanson and Browning, 1956; Hanson and  Kornberg,
(1956).

   The  effect  of trophic  levels on contamination in
animals  is  more fully shown  in Table  4.  These
organisms were sampled  on the same  day at the end
of the pond experiment in their entirety, and the cesium
levels were determined with agammaray spectrometer.

   The  omnivore, as represented by  carp  or man,
reflects  the multiple sources  of food  and has con-
tamination levels lower than those of predators, such
as sunfish or frogs.

   The  pumpkinseed and  crappie are  primary pre-
dators,  feeding  mainly   upon  insects and  crusta-
ceans, although some vegetation may be taken (Simon,,
1946).   The normal diet of  the small  bluegill is not
greatly  different from that of the pumpkinseed and
crappie, but at the time these three  species were
compared, the bluegills (all large adults) were feeding
on  young sunfish  and thus assuming the role of
secondary predator.

   The high accumulation in the higher trophic levels
apparently stems from two metabolic characteristics
of cesium:  high gut absorption and biological half-
life (Tb  1/2) relative to potassium. Ingested cesium
is 50  to  100 percent absorbed from  the  gut by the
animal (Ballou and Thompson, 1958; Richmond, 1958;
Ilin  and  Moskalev, 1957;  McClellan  et al,  1959);
much of  the  total intake, whether adsorbed upon the
surface or  incorporated in the  cells  of  the  food,
is transferred to tissues of the consumer.

   The trophic-level increase, although differentfrom
results obtained with other isotopes (Davis and Foster,
1958; Donaldson, 1954), is  consistent with the pecu-
larities of accumulation and retention of cesium and
potassium.   For example, the Tb  1/2 for cesium
is 13  days  in the rat (Ballou and Thompson, 1958),
25  days  in the dog,  and 110  to  150 days in man
(Richmond,  1958);  the  Tb  1/2 for potassium in the
same three organisms is 4, 8, and 58 days (Richmond,

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358
                   DETERMINATION OF SAFE LEVELS OF TOXICANTS
      Table 4. TROPHIC LEVEL EFFECT ON THE CONTENT OF Cs
               TAKEN FROM A CONTAMINATED POND
                                                                   137
                                                              IN FOUR SPECIES OF FISH
Species
Carp (Cyprinus carpio L.)
Pumpkinseed
(Lepomis gibbosus L.)
White crappie
(Pomoxis annularis Raf .)
Bluegill
(Lepomis m. macrochirus Raf.)
Trophic level
2,3,4 (Omnivore)
3 (Primary predator)
3 (Primary predator)
4 (Secondary predator) c
Cs 137,
H-c/S a
3xlO-3b
6 x ID'3
6x 10~3
2 x 10-2
Concentration
factors
1,000
2,000
2,000
6,500
          Contamination level in water = 3 x 10'^/ic/ml.
        b Contaminants (Zm-65and Zr-95 - Mb 95) approximately equal to 1% of the Cs 137 were
          found in all fish.
        c Stomachs of these fish contained only immature pumpkinseed when sampled.
1958).  Thus,  cesium remains in these organisms at
least  three  times as  long as does  potassium. It
is probable that the same relationship between the
Tb  1/2 of  cesium and  potassium exists in other
organisms.

   When available in sufficient quantity, cesium com-
petes with potassium and may replace more than half
the latter  element in  the  muscle of  frogs and  rats
(Lubin and  Schneider, 1957;  Relman et al.,  1957).
If this condition is general, it is probable that con-
tamination levels of  cesium-137  in animals  are
controlled  only by the availability of cesium  in the
food supply, and  hazardous  concentrations may be
expected if gross contamination occurs.   This is
further indicated by a one-step food chain experiment
in which algae accumulated cesium-137 to 2.2 micro-
curies per gram, and flesh of tadpoles feeding on the
algae accumulated 6.8  microcuries per gram  before
cessation of feeding at metamorphosis.

   Although changes  in dietary potassium have little
effect on accumulation or retention of cesium-137 by
animals (Wasserman and  Comar, 1961), it is probable
that the two ions share the same transport mechanism,
and this factor may partially explain  the differences
inTbl/2.  A possible mechanism is shown in Figure 1.
K+NN(

•£ > KX
< 7
UJ X tfY

K+A
Cs+

	 X Y~
ENZYME
r v V
A _ 	 _ 1
/ N
Cs+ ENERGY
xNa+
/ OUTSIDE

NaY \
1
NaY <

\ INSIDE
V Na +
Figure 1.
"Hypothetical scheme  of a Na+- K+ exchange pump.
The substances  X and Y are assumed to be confined
to the membrane. X has a high affinity for K~*~; Y has
a high affinity for Na+.  X and Y move through the
membrane only  when  in  combination  with  an ion."
Diffusion of No+info and K+or Cs+out of the cell is
shown  with dotted  lines.   (Adopted from Woodbury,
1960).
   If  cesium  enters the  cell in  combination  with
X, and the cesium competes inefficiently with potass-
ium for sites  on the X molecule, the enzyme that
removes potassium from X may not have  the energy
or  configuration to remove cesium efficiently from
the X  substance.  Once  freed, the cesium may have
a  slower passive diffusion rate or form complexes
with the cell proteins, as suggested by Wasserman and
Comar  (1961),  further reducing the rate of egress.
This model fits the known differences in accumulation
of cesium and potassium  (slower uptake of cesium and
slower  outward diffusion), but does not  explain the
threefold  difference in Tb 1/2 that has been noted.
The combination of metabolic factors presented above
for cesium and potassium, however, shows that the in-
creased concentration factors for cesium-137 in suc-
cessive trophic levels can be explained on this basis, and
the organism  must  come  to  equilibrium with its
integrated food base at a contamination level higher
than that of  its food. Observed threefold increases
are further proof of this relationship.  The buildup
to a new contamination level has  been described by
Anderson, Schuch, Fisher, and Langham (1957) who
showed that a stepwise  increase  in the cesium-137
content of food  is followed by an adjustment by the
consumer at  a  higher  level,  theoretically 3.4 times
higher than the  new contamination level in the food.
Richmond,  Furchner,  and  Trafton  (1962)  showed
whole-body  retention  of cesium-137 in mice to be
near  300 percent of the daily intake,  and the same
relationship of  food  level to whole-body burden has
been demonstrated with rams by McClellan, McKenney,
and Bustad (1959). Marinelli and Rose (1957) showed
that in humans the slower excretion rate of cesium
relative  to potassium leads  to a  cesium/potassium
ratio  of from two to three times the ratio in the food
and that Oriental people  contain  smaller amounts
of cesium-137  than people in the  United  States who
consume more  meat and dairy products.  This dif-
ference  emphasizes  the effect of a  shift  from a
predominantly herbivorous diet to a food base more like
that of a predator.  This may partially explain why
populations such as the Swedish Laplanders (Anders-
son, and  Nilsson,  1961) who rely heavily on animal

-------
                        Accumulation of Cesium-137 Through the Aquatic Food Web
                                                                                                        359
products for food have high body burdens of cesium-137
One might predict that high body burdens would be found
in  the  Eskimo  and Indian populations of interior
Alaska and  Canada, and  Massai of Africa.   The
environment of the  interior Eskimo and Indian popu-
lations is a high cesium-137 accumulation area similar
to that of the  Swedish Laplanders, but, essentially,
the reason would be because carnivorous diets should
produce high cesium-137 body burdens compared with
omnivorous or herbivorous diets.  Conversely, lower
levels of cesium-137 should be expected in people who
obtain much of  their  calories  from refined sugar
and oils—both low in cesium-137 content.

   Each  successive trophic level represents a  good
base  for the organism that feeds upon it, with the
same result as a  seasonal or  annual contamination
increase.  The relationship of  trophic level to con-
centration is  better illustrated  diagrammatically:
WaterA °
Cs  137 jn Sol.
3 x 10
                                 ( Algae A *
                                 < CF = 1,000 a
                                 ( 3 x 10-3/iC/g
                      The  contamination level in a predatory fish of 2.7
                   x  10~2  fj.c/g represents a contamination factor of
                   9,000.   This is  in  agreement  with concentration
                   factors for  muscle from  A 3 predators grown in
                   water  contaminated  to  3 x 10-6 ^c/ml  in the pond
                   experiment but is higher than the maximum levels
                   in entire sunfish.
                      In the  aquatic  community, observed increases
                   between  trophic levels were usually less than the
                   expected  threefold  increase in contamination.  This
                   difference becomes clearer when related to the varia-
                   bility  inherent in  food webs.   The food  species
                   consumed  by  an  herbivore  or  predator may  be
                   numerous, and kinds and numbers may change with age,
                   seasons, and  many other factors.  Also, the predator
                   may consume  organisms from several trophic levels.
                   Because the many species consumed by the herbivore
                      Herbivore A 2
                      CF = 3
                      9 x 10-3^ c/g
                                              O
                           Primary predatorA
                           CF= 3
                           2.7 x 10-2yu.c/g
          a Arbitrary concentration factor based upon Table 1.
               Variations in concentrations
               in species and individuals
               stemming from cyclic patterns
               in food-species, kinds of
               foods relative to life cycle,
               equilibrium state, etc.
           Variations in concentrations
           in plants - species and
           environmental effects
            PHOTOSYNTHETIC PLANTS
               A 1; CF'°
                    t
             Cs 137 IN WATER, SOIL,
                    OR AIR
25,000 b

10,000

  500

  400

  300

  200

  100
                                    SECONDARY PREDATORS
                                    A 4.
                                        CF4= 3.5 (Table 4)
                                                              PRIMARY PREDATORS
                                                          > •*  As. CF3 = 2, Toble 4, 3.4 (Anderson et „!.. 1957)
                                                            Variations in food selection t
                                                            latitudes and seasonal
                                                            availability
 HERBIVORES
2: CF2-1.5; 2.8;? 2.8 (Ilin and Moskalev, 1957;
                   McClellan et of., 1959;
                   Richmond et al., 1962)
            a CF1 = Concentration Factor.  CF =
                                                Cs137 in plant
                                                Cs137inA°
              Numbers represent known differences in concentration factors.
                        Figure 2-  Factors affecting variation in accumulation of cesium-137 by organisms.

-------
360
DETERMINATION OF SAFE LEVELS OF TOXICANTS
may each have a  different contamination level, the
body burden of cesium-137 in the consumer represents
an  integration of  all  its  food sources  (Figure 2).
Consequently, a clear-cut threefold increase between
trophic levels should not be expected to occur often
in nature at contamination levels from fallout,  and
the presence of highly contaminated plants or  herbi-
vorous species does not  constitute  an  exception to
trophic level increases. Such organisms may comprise
either  a large or  small fraction of the food of a con-
sumer.

   In the pond study, the theoretical threefold increase
in contamination  from prey  to  predator was well
defined in only one case, i.e.,  juvenile sunfish (2,000)
to bluegill  adult (6,500) (Tables  3,  4), and in this
instance the predator was feeding almost exclusively
on the one species. Invertebrate herbivores, plankton
feeders, and predators (Table  4) showed less contami-
nation  than  many  of  the  organisms  on which they
feed. This apparent reduction resulted from the sam-
pling methods. The insects, crustaceans, andmollusks
were sampled entire, and the concentration per gram
is based upon the whole weight, which includes ceolomic
fluids,  exoskeletons,  and  shells.   This  sampling
method, as shown by Zhadin, Kuznetsov, and Timofeev-
Resovsky (1958),  gives a  concentration  factor  for
the  entire   animal that  is  much  lower than that of
the body sans shell.  The vertebrate predator, feeding
upon these  organisms,  obtains cesium at the level
of the concentration in soft parts and voids the water,
chitin, and  calcareous shell.

                   DISCUSSION

   Because  there is a difference in availability of
cesium-137  to  plants and  animals  in  an aquatic
environment compared with a terrestrial site, meat
and dairy products produced where a large proportion
of the  forage is from wetlands should contain more
of this contaminant than products  from drylands. This
may be  one  factor causing  the  observed variation
in cesium-137 content of milk from different locations
of  similar  rainfall (Anderson, 1958; Booker, 1957),
for it  is probable that uptake of cesium from fallout
by  grasses  growing in saturated or flooded meadows
will be  similar to that of  the grass (Green Bristle
Grass,  Table  1)  rooted in saturated  mud in  this
experiment.  Similarly,  crops grown in saturated
soils or   standing  water  should  contain more
cesium-137 than crops grown in drier soils, as shown
by  Tensho,  et al. (1961). Further, a few dairy herds
might contribute disproportionately to the cesium-137
content of   a local milk supply,  and extensive wet-
lands could elevate the mean contamination level of
a larger region. If cesium-137 contamination in milk
should ever approach hazardous levels, some reduction
might  be possible by preventing dissemination of
dairy products from areas in which high accumulation
Is known to occur, or by  moving the herds to drier
areas.

   The  relative hazard of  cesium-137 accumulation
through an  aquatic versus  a terrestrial environment
may also be illustrated by comparing fish-farming
with grazing.
                              The annual yield of edible meat products from im-
                           proved  grazing land is about 150 to  700 kilograms
                           per  hectare,  and a  hectare of fertilized pond  may
                           provide 300 to 3,000 kilograms of fish (Clarke, 1954;
                           Odum, 1959). By arbitrarily assuming a meanconcen-
                           tration  factor  of 1,000 for the flesh of the fish crop
                           the potential  yield of cesium-137 to  man is many-
                           fold greater per hectare than from a comparable unit
                           of  grazing  land,  because the flesh of cattle should
                           not contain more than three times the cesium level
                           in the forage  consumed.  The contamination level of
                           the terrestrial forage would, under drylands condi-
                           tions, be essentially the  same as the amount  from
                           direct  fallout  less  the amount  fixed  in the  soil.

                              Similarly, a comparison  of the yield  per hectare
                           of fish of three different trophic levels is of  interest.
                           Clarke   (1954), has  shown  that goldfish  (Carassius
                           auratus  (L.),  which are mainly herbivores,  may
                           yield 500  kg/ha/yr,  but  bluegill, a primary carni-
                           vore,  yields  250  kg/ha/yr and  bass, a secondary
                           carnivore, yields only 100 kg/ha/yr. The productivity
                           ratio of  these three fish  is 5:2.5:1.    In the pond
                           experiment,  carp, sunfish,  and bluefill represented
                           the three  trophic  levels  described by  Clarke.  It
                           is of interest that the  concentration factors for the
                           three trophic  levels make  a ratio of  1:2:6.5  and,
                           when these values are  multiplied by the productivity
                           ratio, the products are  quite similar. This may in-
                           dicate that  the levels of cesium-137 in trophic levels
                           of  an aquatic  site  may  be  useful to determine the
                           relative balance of the  unit as well as the degree of
                           predation  and probable foods of individual species.
                            Trophic Concentration factor Productivity
                              level         ratio            ratio       Product
2
3
4
1
2
6.5
X
X
X
5
2.5 =
1
5
5
6.5
                              One might  infer  that under balanced  conditions,
                            the  amount  of  cesium-137  in the standing  crop of
                            fish  will  be divided somewhat equally  among  the
                            three  trophic levels, but, because the higher trophic
                            levels obtain the same or slightly greater amounts
                            of  cesium-137  from  fewer kilograms  of fish,  the
                            hazard relative to food for  man would increase with
                            the  trophic  level.   This effect  may be  augmented
                            by the preference  for  food of fish from the higher
                            trophic levels.   The low yield  of predaceous fish
                            from most natural fresh waters, however, would not
                            contribute much cesium-137 to local populations unless
                            a high proportion of the food  was from this source.
                               The effects  of high accumulation  in  the  higher
                            trophic levels are also of interest in regard to the
                            maximum permissible  concentration  (MPC)    for
                            cesium-137 in drinking water of 4 x 10  microcuries
                            per  milliliter  (NBS  Handbook  69,  1959).   Simple
                            calculations  show that  flesh from a fish grown in
                            water contaminated  to  the MPC will become much
                            too contaminated for use as human food. For example,
                            flesh  of  the  pumpkinseen accumulated cesium-137

-------
                        Accumulation of Cesium-137 Through the Aquatic Food Web
                                              361
to  3 x 10"^ microcuries per  gram  weight from
foods grown in water  containing 3  x 10~6 micro-
curies per milliliter.  Only  2.2 pounds  of this flesh
would supply 30 microcuries of cesium-137, a quantity
equal to the long-term, maximum permissible whole-
body burden for this isotope.  If  similar increases
occurred  at the MPC  level for water, the  predator
could accumulate 3.6 microcuries per gram, and less
than 10 grams would contain 30 microcuries. Although
the MPC  for drinking water was not intended as a
criterion  for disposal  and the use  of  the 40-hour
level is questionable, having been used for illustration
only,  the  above comparison  suggests that disposal
to fresh water should  be kept at least 10-3 iess than
the MPC  for drinking water.  In the absence of in-
formation, however, about accumulation of cesium-137
by organisms in many,  different aquatic communities,
advancing an "ecological  MPC" for  this isotope is
not justified.

   The basic differences in the availability of cesium-
137 to  the  foods of man from aquatic as compared
with terrestrial sources are  summarized in Table 5.
   From the comparison of availability of cesium-137
to foods through the aquatic and terrestrial food routes,
it may be inferred that, although the  major portion
of cesium-137 in the world's population will come from
terrestrial sources, the  probability of accumulation
of hazardous quantities is much greater from aquatic
or wetland environments.

   Differences  in  ecological conditions  cause great
variation in accumulation of cesium-137 inorganisms,
and  the  differences ascribable to water abundance
exceed  those from soil chemistry or type  by many
orders of magnitude (Fowler and Christenson, 1959;
Pendleton and Uhler, 1960).  These variations suggest
that  evaluation  of hazards from cesium-137  in fallout
should be made on local, rather than a region-wide,
basis since populations with specialized food habits
that  live  in  an area where high absorption occurs
could be  receiving  much  more  radiation  than  the
regional mean.  Trophic level increases of approxi-
mately threefold • add to the problem.

   Cesium is apparently not accumulated in marine
environments to the same degree as in fresh water
(Revelle and  Schaefer, 1958); hence, high concentra-
tions of cesium-137 should not be expected in foods
from the ocean. Also, in large bodies of fresh water
such  as rivers and lakes  where dilution  is great,
lesser hazards should accrue, although eviscerated
trout from streams and  lakes in Utah  (Sept. 1962)
contained  700 picocuries of cesium-137 per  kilogram
while flesh of  mule deer, feeding in the same area
on plants  heavily contaminated by fallout, contained
about the  same level (Pendleton, Unpublished manu-
script). Dilution in these aquatic  situations was great
as compared with the terrestrial condition.
             Table 5. COMPARISON OF FACTORS THAT AFFECT CONTAMINATION LEVELS
                      OF Cs 137 IN THE  FOODS OF MAN
                     Aquatic food route
           1. Reduction by dilution and adsorption
              on mud.

           2. Rapid absorption by algae and other
              plants, increased root absorption,
              plus external adsorption or entrap-
              ment.

           3. Concentration factor >50.
           4. Level in plants greater than environ-
              mental contamination.
           5. Two to four trophic levels available to
              man. Man feeds upon 2, 3, or 4.
        Terrestrial food route
  1. Reduction by adsorption on soil
    particles.

  2. Limited foliar absorption, low root
    absorption, plus external adsorption
    or entrapment.


  3. Concentration factor <1.

  4. Level in plants less than or equal to
    the level of environmental contami-
    nation.

  5. Normally not more than three trophic
    levels available to man. Man feeds on
    1 or 2.
                                             REFERENCES
Anderson, Ernest C., Robert L. Schuch, W.R. Fisher,
and Wright Langham.  1957.  Radioactivity of People
and Foods. Science, 125: 1273-1278.


Anderson, Ernest C. 1958. Radioactivity of People and
Milk. Science, 128: 882-886.

Andersson, I.O.,and I. Nilsson. 1961. Radioactivity in
reindeer-breeding Laplanders living in the north  of
Sweden.    Personal  report  (Arbetsrapport SSI-2).
Anderson, Robert W.,and Philip F. Gustafson.  1962.
Concentration of  cesium-137  in human rib  bone.
Science, 137: 668.

Ballou, J.E.,and R.C. Thompson, 1958.  Metabolismof
cesium-137  in the  rat:   Comparison of acute and
chronic administration experiments. Health Physics,
1: 85-89.

Booker, D.V. 1957.  Radio-caesium in dried  milk.
Physics in Med. & Biol. 2: 29-35.

-------
362
DETERMINATION OF SAFE LEVELS OF TOXICANTS
Christenson, C.W., E.B. Fowler, B.L. Johnson, E.H.
Rex,andRF.A. Virgil.  1958. Soil adsorption of radio-
active wastes at Los Alamos.  Sewage and Industrial
Wastes.  30: 1478-1489.

Clarke, G.L. 1954.  Elements of Ecology.  John Wiley
and Sons, New York.

Davis, J.J.,and  R.F. Foster. 1958. Bioaccumulation
of radio-isotopes through aquatic food chains. Ecology,
39: 530-535.

Donaldson,  L.R., 1954.  Biological cycles of fission
products in aquatic systems as studied at the Pacific
Atolls of  Bikini  and  Eniwetok.    A.E.C.U. 3412.

Fowler,  Eric B., and C.W. Christenson, 1959. Effect
of soil nutrients on plant uptake of fallout. Science,
130: 1689-1693.

Hanson,  W.D.,  and R.L. Browning.  1956.  Role of
food habits  in wildlife contamination at Hanford.  (in)
Biology Annual Report. HW-47500.

Hanson, WJ5., and H.A. Kornberg. 1956. Radioactivity
in terrestrial animals near an atomic energy site.
Proc.  International Conf.  on the Peaceful Uses of
Atomic Energy.  13: 385-388.

Ilin, D.I., and Yu.  L Moskalev. 1957. On the meta-
bolism  of  caesium, strontium, and a mixture of /8 -
emitters in  cows.  Journ. Nuclear Energy  5: 413-420.

Klechkovsky, V.M. (Ed.) 1957. On the  behavior of
fission products in soil, their  absorption by  plants,
their accumulation in crops.  Acad. Sci., U.S.S.R.,
A.E.C.TR. -2867.

Knobf, V.I.,  1951.  Studies of radioactivity in fish from
White Oak  Lake and the Clinch River. ORNL-1031.

Krumholz,  L.A., 1956. Observations on the fish pop-
ulation of a lake contaminated by radioactive wastes.
Bull. Amer. Mus. Natural History.   110: 281-367.

Langham, W.H., and E.G. Anderson.  1957.   Sr-90
and  Cs-137  in relation to  the problem of worldwide
radioactive  fallout,   (in) The Nature of  Radioactive
Fallout and  its  Effects on Man.   Special Committee
on Radiation of the Joint Committee on Atomic Energy.
Congr. of the United States, p. 751-752.

Langham, W.H., and E.G.  Anderson.   1959.  Cs-137
biospheric contamination from nuclear weapons tests.
Health Physics,  2: 30-48.

Libby, W.F. 1957.  Radioactive Fallout. Proc. National
Acad. Sci. (U.S.) 43: 758-775.

Lubin, M., and  P.B. Schneider.  1957.  The exchange
of potassium for cesium and rubidium in frog muscle.
British Journ. Physiol. 138: 140-155.

Marinelli, L.D.,  and J.E. Rose.  1957. Occurrence of
Cs-137 in the atmosphere, biosphere, and its uptake
and behavior in  man.  (in)  The Nature of Radioactive
Fallout and its Effects on Man.  Special Committee on
Radiation of the Joint  Committee on Atomic Energy.
Congr. of the United States.  764-765.
                           McClellan, R.O.,  J.R.  McKenney, and  LJD. Bustad.
                           1959.  Metabolism and dosimetry of  Cs-137 in rams.
                           (in) Hanford Biology Research Annual Report for 1959.
                           HW 69500.

                           Miller, C.E., and L.D.  Marinelli.   1956.   Gamma-
                           ray  activity  of  contemporary man.  Science, 124:
                           122-123.

                           Neel, J.W., J.H. Olafson, A.J. Steen, B.E. Gillooly,
                           H. Nishita, and K.H. Larson.  1953.  Soil plant inter-
                           relationships  with respect  to the uptake  of fission
                           products. UCLA-247.

                           Nishita,  H.,  B.W. Kowalewsky, and  K.H. Larson.
                           1954.  Fixation  and extractability of fission products
                           contaminating various soils and  clays:   I,  Sr-89,
                           Sr-90,  Ru-106,  Cs-137, and Ce-144.   UCLA-282.


                           Odum, E.P.   1959.  Fundamentals  of  Ecology,  2nd
                           Ed. W.B. Saunders Co., Philadelphia, Pa.

                           Pendleton, R.C., and W.C. Hanson. 1958. Absorption
                           of cesium-137 by components of an aquatic community.
                           Second U.N.  International Conf. on the Peaceful Uses
                           of Atomic Energy. 18:419-422.


                           Pendleton, R.C.  1959.  Effects of some environmental
                           factors on bioaccumulation of cesium-137 in  an aquatic
                           community.   (in) Biology Research Annual Report.
                           1959, HW-59500.

                           Pendleton, R.C.,and R.L. Uhler.  1960. Accumulation
                           of caesium-137 by plants grown in simulated pond, wet
                           meadow, and irrigated field environments.  Nature,
                           185: 707-708.

                           Pendleton, R.C.  C.W. Mays, RJX  Lloyd, and B.W.
                           Church. Radionuclides in  soils, vegetation,and wildlife
                           in the high Uinta Mountains of Utah. Unpublished Man-
                           uscript.


                           Rediske, J.H.,andF.P.Hungate. 1955. The absorption
                           of fission products by plants.  Proc.  International Conf.
                           Peaceful Uses of Atomic Energy, 13: 354-356.

                           Relman,  A.S., A.T. Lambie, B.A. Burrows, and A.M.
                           Roy.   1957.  Cation accumulation by muscle tissue:
                           The  displacement  of potassium by rubidium and ces-
                           ium  in the living animal.  Jour. Clin. Invest., 36:
                           1249-1256.

                           Revelle,  R.,  and M.B. Schaefer.  1958.  Oceanic re-
                           search needed for safe disposal of radioactive wastes
                           at sea. Proc. Second International Conf. Peaceful Uses
                           of Atomic Energy, 18: 364-370.


                           Richmond, C.R.   1958.   Retention and excretion of
                           radionuclides of the alkali metals by five mammalian
                           species.  LA 2207.

                           Richmond, C.R., J.E. Furchner, and G.A. Trafton.
                           1962.  Comparison of predicted and measured equili-
                           brium levels for  chronically administered Cs-137.
                           Health Physics, 7: 219-225.

-------
                        Accumulation of Cesium-137 Through the Aquatic Food Web
                                               363
Simon,  J.R.   1946.  Wyoming Fishes, Bull. No. 4.
Wyoming Game and Fish Dept., Cheyenne, Wyoming.

Tensho, Kiyishi,  Ko-Ling  Yeh, and  Shingo  Mitsui.
1961.   The uptake of strontium and cesium by plants
from soil with special reference to the unusual cesium
uptake by  lowland  rice and its mechanism.  Soil and
Plant Food, 6: 176-183.

Wasserman,  R.H., and  C.L. Comar.  1961. The in-
fluence of dietary potassium on the retention of chroni-
cally ingested  cesium  in the rat.   Radiation Res.,
15: 70-77.
Woodbury, J. Walter.  1960.  (in) Medical Physiology
and Biophysics.  18th Ed. Edited by T.C. Ruch and
J.F. Fulton. W.B. Saunders Co., Phila.


Williams, Lewis G., and HJ).  Swanson.  1958.  Con-
centration of Cs-137 by algae.  Science, 127:187-188.


Zhadin,  V.I., S.I.  Kuznetsov,  and  N.V. Timofeev-
Resovsky.  1958.  The role of radioactive isotopes
in solving the problems of hydrobiology. Proc. Second
U.N. International Conf. Peaceful Uses of Atomic Ener-
gy, 27: 200-207.
                                               DISCUSSION
                 (Paul O. Fromm)


   Dr. Fromm's paper was  presented and discussed
first.  It was followed by Dr. Alderdice's paper and
further discussion.  Dr.  F.E.J. Fry,  who was asked
to make  some general  comments by way of summary,
noted  that Dr.  Fromm is seeking some  sensitive
measure  or index  of chronic intoxication that is
largely divorced from the result of primary concern,
namely,   eventual damage  to the  organism.   Dr.
Alderdice's objective,  it was pointed out, is very
different.   The  system of analysis and  the models
presented  and explained  by  him will  facilitate con-
sideration of  the  toxicity  (demonstrably  harmful
action) of a water  pollutant under  a wide variety
of circumstances or combinations of environmental
conditions that may  occur in nature.  The interaction
of environmental variables or factors that may jointly
influence the toxicity in otherwise unforeseeable ways
can thereby be effectively investigated.   Among the
questions raised in  the course of the informal dis-
cussions were the following:

   (1)  Can a substance whose action  is not demon-
strably fatal or incapacitating be referred to properly
as a  toxic substance, and what is  the correct dis-
tinction,   if there  is   any,  between  "chronic"  and
"subtle*  effects of a toxicant or water  pollutant?  The
consensus  of opinion seemed to be  that a substance
that  is not acutely  toxic and even one that is in-
capable of incapacitating  an  organism or causing its
death after prolonged  exposure can nevertheless be
said correctly to be  a toxic substance.   Chronic
intoxication kills or incapacitates only after a long
time or period of exposure. Subtle effects of toxicants
may be  such  effects  as  a reduction  of the exposed
subject's  appetite (food intake)  or some deformity
of young  produced  by exposed adults who are not
themselves demonstrably affected.
   (2)  Is  not  the  assumption that histological, bio-
chemical, or other evidence of changes in the tissues
or  cells  of  aquatic animals  exposed to water con-
taminants indicates significant or  incipient injury to
the  organisms  and to  their  productivity often an
unjustified assumption?  In other words, before much
practical significance can be attached to such evidence,
is it not  necessary clearly to demonstrate  that the
observed responses are not inconsequential or merely
adaptational  and that  they are  indeed  accompanied
or  followed  by some related  impairment  of per-
formance or of functions essential to the continued
well-being and  undiminished productivity   of  the
animals?   This  question was not fully answered. It
was  noted  that  biochemical  and histopathological
studies often explain  previously observed  harmful
effects of toxicants.  However,  the  statement was
made  also that the manner  of action of toxicants
usually is  not  really known or  fully understood.
This observation suggests that the effects of toxicants
of the  cellular  or tissue level (biochemical, etc.)
that  have  been reported  and measured are not often
effects that have been shown definitely to be directly
related to the lethal  action  of the  toxicants or to
any  observed  functional impairment  at  sublethal
toxicant concentrations.   The need for establishing a
direct  connection and quantifying the relation between
the former effects and  effects on the performance
of the  organism as a whole  seems to  have been too
often neglected.   The comment  was made that fish
toxicologists are far ("90 years"!) behind mammalian
toxicologists, who certainly have given more attention
than have  fish toxicologists  to  the  evaluation  and
explanation of the  subtle effects of sublethal  levels
of intoxication on performance, behavior, etc.  How-
ever,  no  evidence  was  brought forth to  show that
mammalian toxicologists have already achieved great
understanding or knowledge of the relations  between
these  subtle  effects  and the observed biochemical
or other changes in mammalian tissues, and so are

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364
                            DETERMINATION OF SAFE LEVELS OF TOXICANTS
not any longer faced, in large degree, with problems
such  as  those  considered  above  with particular
reference to fish and other aquatic animals.

   (3) What can be done to promote intensified bio-
chemical, physiological, and pathological research re-
lating to problems of water  pollution and its effects
on aquatic life?  It was pointed out that biochemists,
pathologists, etc.,  now have plenty of work to do with-
out becoming  involved in problems of fish toxicology
and they must be  somehow attracted to work in this
field.   Better financial support for  the studies in
question appears to be  the key to the solution of this
problem.    However, it is  much  easier to obtain
financial support for  applied research of evident and
immediate practical value than for more basic  re-
search, and for this reason applied research, moving
ahead of basic research, is often seriously hampered
by  a dearth  of  essential basic data and principles.
To  ensure much better support for the needed basic
biochemical,   physiological, and  other  studies,  the
practical utility of data or knowledge obtained through
such  studies  (i.e., the  efficiency of the  approaches
to the solution of  practical problems that are based
on these findings) must be clearly demonstrated, as
suggested earlier  {see item 2).

   (4) Dr.  Alderdice  was  asked whether the model
that he had  presented  and  discussed in explaining
his system of experimental design  and  analysis of
bioassay  results  was intended to serve predictive
purposes  or to serve only  as a basis for the planning
of additional  tests. He replied that he expects that
it will have demonstrable predictive value or utility.
ments  would be very helpful in evaluating the sub-
lethal  effects of toxicants.   The  only answer that
could be  given  to  the  question, however, was that
we  can only accumulate data of  similar nature, and
after enough is  obtained,  then  perhaps  it can  be
fitted  together  to  give a  nearly  complete under-
standing of the effects.

   Further discussion revealed a feeling by some that
the choice of the above-mentioned type of approach,
or the  approach using more gross effects  such as
daath and  growth, depends upon the time one may have
available  to determine  acceptable  concentrations.
Although the use of such sensitive tests might reveal
more closely the true level of no deleterious effect,
it  may be necessary to use more direct approaches
to  set  an  approximate safe level when time is very
short.     The approximate  levels, however, should
be revised in light of more refined research.

   Representatives from England pointed out that their
philosophy is to set maximum permitted concentrations
based  on  a  safe level for three months.  A three-
month  interval is used because it corresponds to the
period of  low flow,  characteristic  of their streams.
They also consider that  there is  a  minimum level
that  is always present, regardless of flow,  and this
level must also be safe for extended periods.

   One concept was  crystal clear from this discussion
as well as from the conference, namely, that a  colossal
amount of work  must be done with sub-lethal con-
centrations before  sound  judgement can be  made
as  to  what levels of  toxicants  are  really   safe.
                (Charles G. Wilber)

   In using the organ to body weight  ratio, care must
be exercised  to account for the normal physiological
changes of the organs as, for example, the storage
role of the  liver.  By  comparison with the control
group, however, these changes can often be overcome.

   The suggestion was  made that any  "measurable"
concentration of copper  is deleterious.  After some
discussion of what  is  meant by "measurable," the
question  was answered  on theoretical grounds that
copper is a necessary trace element, and, therefore,
there must be some concentration that would not be
considered harmful.
    (Behavioral Responses of Fish to Toxicants)

   Mr. Richard Warner presented unpublished toxi city
data on fish exposed to  toxaphene for 24 hours and
oubsequently rested in fresh water  24 hours before
testing.  He used as the endpoint, the ability of the
fish to acquire a conditioned response.  Fish exposed
to  concentrations  as low  as 0.064 ppb evidenced
marked differences from the  controls.   He closed
Ms presentation by  asking  how  such data can  be
extrapolated to the natural situation.

   As  a  whole, the  group  was impressed with the
sensitivity  of this  test  and felt  that  such experi-
                 (John B. Sprague)

   Observations were reported that indicate that small
concentrations  of  copper  do  cause some aquatic
animals  to  increase  their activity.   Many  unex-
plainable points concerning the pattern evidenced by
Dr.  Sprague's  data  were  discussed, but no  firm
conclusions were reached.
         (Comments on Dr. Sprague's paper
               by Charles B. Wurtz)

   Dr. Sprague introduced his comments on salmon
avoidance of heavy metals with a slide showing curves
for the movement of salmon and the amount of rain-
fall for the year 1956.  These data were grouped in
5-day  units.   He did not mention  that the salmon-
counting fence was  washed  out by high  flows  for
short periods  in  1956, and, therefore, an accurate
count of salmon was not possible.  The inaccuracy
of  the  salmon count would  be aggravated by  the
upstream surges  of salmon  that are a product of
freshet flows.

   The  second  slide   showed the  1960 upstream-
downstream salmon  movement in association with a
curve  for  zinc concentration.  No  values were  ex-
pressed  for  the  zinc  concentrations,  but  the cor-
relation between higher zinc loadings and increased
downstream  salmon movements was  not  clearcut.

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                                                Discussion
                                               365
No apparent  attempt  was  made to correlate the
downstream movement with  any other factor.  And,
once again, the salmon-counting fence was washed out
by high waters for that year, rendering an accurate
count of fish impossible.

   The fourth slide shown correlated the 1961 salmon
movements with the "toxicity index" method developed
by  R. Lloyd (Stevenage,  England).   The correlation
with  this very useful concept of Lloyd's was much
closer than the correlation with the direct measure
of zinc.   However,  the  basic data from which the
curves were developed are open  to question.   The
"toxicity  index*  is a  function of three variables:
Zinc concentration, copper concentration, and hard-
ness  of  water.   Upon query,  Dr. Sprague advised
the group that  dally  analyses had been performed
for  zinc and hardness,  but that  copper was only
measured once a  week.  In  addition,  although not
brought  forth during  the discussion, the source of
the samples analyzed differed. These samples were
drawn from  two locations that are 6.4 river miles
apart.  Dr. Sprague  believes these sampling points
to be virtually the same in water quality character-
istics.   This is  most dubious.   The  lack of exact
counts of the  upstream-downstream movements of
salmon, as mentioned above,  would further depreciate
the value of the curves as shown.
    (Answers to comments by Dr. Wurtz on paper
                 by J.B. Sprague.)

   As  Dr. Wurtz points out,  it is unfortunate that
the salmon-counting fence was not flood-proof.   A
hr.stogram of  salmon  movements  during 1956 was
shown  at the  meeting to illustrate the usual move-
ments  of fish before the mine was active.  For the
period from June  5 to  November 13,  1956, shown
in the slide,  the fence  was inoperative  only once,
from June 15  to June 18. Of the salmon movements
recorded that  year, 2% of those going upstream came
back downstream.

   In  1960, the  counting fence was  inoperative for
3 days in late  June, 3 days in late October, and was
partially  inoperative for one additional day in late
October.  These periods were indicated in the slide
shown  at the  meeting,  and in Figure 1.  Similar
inoperative periods  in 1961 are shown in Figure 2.

   During the  winters, samples were taken 6.4 miles
upstream of the  counting fence, but all samples in-
cluded in this paper were taken at the counting fence.
The concentrations of copper in the Miramichi were
very low,  and difficult to analyse accurately.  Ac-
cordingly they were calculated for  1961, for measure-
ments  of copper in the polluted tributary.  This was
done on  the basis of the dilution ratios indicated by
the concentrations of zinc at the same two locations.
Refinements of analytical technique in 1962 show that
this gave valid estimates.  Sometimes the estimates
of copper in 1961 were  available  only  once a week.
However, as  shown in Figure 2,  they  were usually
more  frequent, as often as once a day. Suggestions
for alternative explanations of the unusual disturbed
migration would be welcomed by the author.
                 (Peter C. G. Isaac)

   A  discussion  followed  in regard  to  the  oxygen
demand resulting from the respiratory activities of
benthic organisms.  The general opinion was that the
bottom organisms do, in fact, contribute greatly to
the oxygen demand of bottom muds.

   Dr.  Gunderson  described in  brief a pollutional
survey that was carried out on the Sacramento River,
a relatively unpolluted stream.  A point of interest
was the fact  that while some sections of the river
had the classical  diurnal oxygen curve, other sections
revealed  a totally inverted oxygen  curve; that is,
the oxygen levels rose during the night.  Although
there was no suitable explanation for this phenomenon,
a suggestion was  made that the variation in the respi-
ratory activity of the bottom organisms might account
for it.  It was also suggested that the higher oxygen
levels at  night might  be  due to  the presence of a
chemical   source of  oxygen, such  as nitrates, to
the release of oxygen bubbles from  the  steams and
leaves  of  higher plants,  or perhaps  to "moonlight
photosynthesis."

   Dr.  Ohle pointed out that the oxygen demand of
bottom muds  and  sediments is  often increased by
the presence  of gases,  especially  methane.   In
addition to the oxygen  necessary to  oxidize these
gases, some bacteria use these gases as a substrate,
thereby further increasing  the oxygen demand.
   In  discussing  the standards for suspended solids,
it  was brought  out  that  the allowable  levels of
suspended solids  should depend upon the  receiving
waters, and, therefore, should vary.

                  (Dr. F. E. J. Fry)

   The discussion following Dr. Fry's presentation
ranged over a wide variety of subjects:

   (1)  Anaerobic  metabolism in  fishes.    There is
evidence  that  anaerobic metabolism  in fishes  can
be important under some conditions, but it is difficult
to  measure, and consequently the  extent of its possible
influence,  under  different  circumstances,  upon the
reliability of  metabolic rate  determinations  based
on  evaluations of  oxygen  consumption rates is not
yet clear.

   (2)  Influence of D.O. and free CO2 on fish embryos
and larvae.   Available  data indicate  that the  sen-
sitivity of fish to reduction of dissolved oxygen is
greatest just before hatching and decreases sharply
thereafter.  There is very little information available
on  the influence  of free carbon  dioxide  on the dis-
solved oxygen requirements of larvae and embryos
at different stages of development.

   (3)  Influence of water velocity on embryonic  de-
velopment  of fish.   There  was no disagreement with
regard to  the expressed opinion that the flow of water
past fish  embryos probably influences their develop-
ment   (developmental rate, size  of fry at  hatching,
etc.)  chiefly by determining the  rate of  delivery of
oxygen to  the chorion surfaces  and not the  rate of
removal of metabolites,  but  more  information on
this subject is needed.

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366
DETERMINATION OF SAFE LEVELS OF TOXICANTS
   (4) Dependence of oxygen uptake rates of aquatic
invertebrates  on  oxygen  concentration  and  water
velocity.   The probable significance was discussed
of the frequently reported observations of  dependence
of the oxygen consumption rates of supposedly resting
and fasting invertebrate animals (e.g., aquatic insects,
etc.) upon oxygen  concentration and water  velocity
even at high dissolved oxygen and water velocity levels
far above those necessary for  continued  survival
of the  animals.    One explanation that has  been
suggested  is  that   the  measured  metabolic  rates
of the animals  in question actually were far  above
the true  resting levels (i.e., were "active" metabolic
rates), because  of the existence of an "oxygen debt,"
some persistent activity, or invisible muscular ten-
sion,  etc.,  resulting from  recent handling or other
disturbance of the  animals or evoked by unnatural
environmental conditions. It is known that the oxygen
uptake rate of fish may remain far above the standard
rate and dependent on oxygen  concentration at rather
high dissolved oxygen levels  for a number of hours
after  introduction of  the fish into a respirometer.
However, K.H.  Mann  presented  some data on the
oxygen  uptake  rates  of different leeches  showing
dependence of  the  rates  on oxygen  concentration
(at  high  as well as  low  D.O.  levels)  that did not
seem to be readily explainable in the manner sug-
gested above.  The suggestion  that a great depression
of oxygen uptake rates at reduced oxygen  concen-
trations  may be due to suppression  of metabolic
processes involving translocation of body substance
(i.e.,  "growth"  at  the expense  of  stored energy
sources  such as fat  deposits) was considered, but
it was  rejected as an erroneous  or unlikely  ex-
planation of the phenomenon under  consideration,
except in  the case of a growing embryo or larva
that  derives nourishment from yolk.  Finally, the
suggestion was  considered and  generally  accepted
that a progressive  increase of the ratio of anaerobic
metabolism to aerobic metabolism resulting from a
progressive  decrease  of oxygen availability  could
account  for an observed  decrease  of the  rate  of
oxygen uptake.  No  objection  was raised to the view
that, if life can be sustained increasingly by anaerobic
metabolism as  the  dissolved oxygen  concentration
falls, a metabolic rate far above the basal rate (true
resting   level)  at high oxygen concentrations  need
not be postulated to explain the ability of an animal
to tolerate for long periods lower oxygen concentrations
at which the oxygen uptake rate  is greatly reduced.
It was not possible to decide which one  of the sug-
gested, plausible explanations of the phenomenon under
consideration  is more generally appropriate   or
correct.

   (5) Influence  of  the dissolved  salt content  and
hardness of water  on fish and on their resistance
to disease and  to  temperature extremes.   S.  F.
Snieszko  reported  that fish  appeared to be  more
susceptible to  kidney disease in soft  water than in
harder water.  Fish kept in demineralized water for
a week  survived and suffered no  apparent  osmotic
shock  on  return to  their normal  medium  (fresh
water).  F.E.J. Fry stated that water hardness seems
to influence the thermal tolerance  of fish; in soft
water  they are apparently more tolerant  of high
temperatures  than  in harder water.  P. Doudoroff
                           remarked that secondary chill  coma  and death of
                           marine and fresh-water fish that are exposed to lethal
                           low temperatures can be delayed but probably cannot
                           be prevented entirely  by adjusting the salinity of the
                           medium  so as  to  render it approximately isosmotic
                           with  the body  fluids  and thus prevent  the  lethal
                           effects  of osmo-regulatory failure  that  occurs at
                           the low temperatures.

                              (6)  Evaluation  of activity and metabolic rates of
                           fish in the laboratory and under natural conditions.
                           Devices  for the measurement of spontaneous activity
                           of  fish  in  the laboratory, as  related  to  rates of
                           oxygen  consumption, etc., were described and dis-
                           cussed.   The  difficult  problem of how to estimate
                           metabolic  rates   of  normally  active fish in their
                           natural environment also was  considered.  Accurate
                           determinations of the  food intake of these fish, as
                           well  as other pertinent data, presumably will  be
                           necessary  for  arriving at reliable estimates  of
                           their average metabolic rates.

                                               (Pendleton)
                              The  cycling  of cesium  was  discussed with the
                           general conclusions that insufficient data are presently
                           available concerning the cycling and distribution of
                           cesium among  the various fractions (water, colloids,
                           silt, detritus, and biomass) in aquatic environments.
                           At  low  concentrations in fresh water all cesium ions
                           become  bound to colloidal  and suspended matter.
                           The relationship  of  the behavior  of  cesium  and
                           potassium has  been shown to be quite different from
                           that of  strontium and calcium.  Cesium at highest
                           trophic  levels  is concentrated  threefold that of
                           chemically similar potassium.  In an aquatic environ-
                           ment,  the availability of cesium adsorbed to mud and
                           silt has  not been  defined.  However, aquatic rooted
                           plants have been reported to be able to break this
                           adsorption bond.    Because of  the vast individual
                           differences,  maximum  concentration   factors for
                           cesium should be reported for each species.
                              Methods were discussed for separating and measur-
                           ing the percent of cesium in plankton, detritus, and
                           the inorganic fractions.  Because cesium is known to
                           move more freely in aquatic and moist environments,
                           questions were raised about its uptake and movement
                           in rooted plants producing aerial shoots.  Biological
                           transport of  cesium in submerged aquatic organisms
                           is less pronounced in warmer waters of the tropics
                           than in cooler  waters, partly because of differences
                           in  the rate of diffusion that  brings about a more
                           rapid turnover in the warmer waters.

                              Some of the  present techniques of quantitating
                           the amount of cesium  present  in living  cells are
                           inadequate because they  fail to measure the cesium
                           held within membranes  in cell saps.   This soluble
                           cesium has been shown to be  in high concentrations
                           within phytoplankton cells.

                              New waste disposal methods will have to be de-
                           veloped  to handle the future supply of  cesium-137.
                           The present tank storage methods are not the answer.
                           Cesium-137is a greater genetic hazard than strontium
                           90  and iodine- 131,  which are somatic  hazards.  In
                           the food web to  highest trophic  levels, cesium is
                           more  concentrated  than most  other  radionuclides.

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                                          Summary of Discussion
                                            367
                           TEMPERATURE EFFECTS ON THE AQUATIC BIOTA

                                       SUMMARY OF DISCUSSION
   Extensive and intensive discussion was stimulated
by this paper.   The most outstanding points included
the following:

   1.  Heated water below power plants attracts fish
      from  the  surrounding  areas.  This was cor-
      roborated  elsewhere in the United States. At-
      tracted  fish  included  salmonoids  in winter,
      but ran heavily in warm-water types in summer.

   2.  There is  no  information available  relative  to
      changes in productivity of fish, since the area
      cannot be  effectively  studied.  Dr.  Trembley
      feels that  in the study  he reported productivity
      was probably limited by heavy blue-green algae
      growths that  occurred throughout the  year  in
      the heated-water area.

   3.  There seemed  to  be  general agreement that
      life  cycles are  speeded  up in warmer water
      areas. Tendipeds  were reported as emerging
      on a year-round pattern in Pennsylvania, except
      for a limited period during the hottest weather.
      Threadfin  shad were  reported as spawning 1
      month ahead of time in a southern river. Net-
      building caddis  flies,  Hydropsychidae,  were
      reported to be stimulated to  grow and emerge
      on a year-round basis  below a power  plant in
      the Muskingum River, Ohio.

   4.  The subject of heated waters having significant
      organic  content  (biochemical oxygen demand)
      was discussed.  It was  generally recognized
      that such waters might present great difficulties.
      A  situation in Michigan was reported in which
      a power plant upstream  from a sewage plant
      heated  the water  to  a  point where  serious
      anaerobic  conditions developed below the plant.
      This  situation was ameliorated by the instal-
      lation of  a  cooling tower  and recirculation.
      It was the  opinion of some that although speed-
      ing up natural  self-purification processes  in
      the  winter might  result  in  a  beneficial re-
      duction of sludge  deposited, in  summer the
      increased  digestion rate would be  more likely
      to result in anaerobic conditions.
5. The  benefits of weirs and jetties in effecting
   mixing of heated  waters with natural stream
   waters was  illustrated by the situations in the
   Delaware  River, and in theThames River in
   England.   Different physical principles were
   involved  in the two cases; however,  in the
   Delaware the hot waters were channeling along
   one bank, whereas  in the Thames  they were
   definitely  channeling at  the  surface in mid-
   stream, eventually spreading out entirely across
   the  stream.   Information  on distances that
   heated waters  might traverse before complete
   assimilation into the stream in the absence
   of weirs or jetties was not available.

Other topics discussed included:

1. The  shock effect  of temperature changes  on
   fish;

2. the  desirability of considering fish management
   needs when  planning power plant installations;
3. the  reduction  of dissolved oxygen at elevated
   temperatures;

4. the  difference  between  the  "peak load" plant,
   which  may at  "peaking* hours raise the water
   temperature as much as 25° Fin passing through
   the  plant,  and the "base load" plant, which may
   raise  the temperature of the cooling water only
   10°  to 12°;

5. an  extended discussion  of a power plant on the
   Thames River, England,  in which it was  con-
   cluded that  "detrimental effects seem to  be
   negligible.'
Suggested needed research:
                                            for
1. The   normal   maximum   temperatures
   aquatic life, including bacteria;
2. the  effects of raised water temperatures on the
   total biota of streams and lakes  in  diverse
   areas;
3. the   correlated effects of heated water, BOD,
   COD, and digestion of organic wastes.

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368
DETERMINATION OF SAFE LEVELS OF TOXICANTS
                       EFFECTS OF POLLUTION ON OYSTERS AND FISH IN TAIWAN

                                         Professor Poo/Shu Chang *
   Taiwan is an archipelago situated in the semi-
tropical zone at the crossing of the warm and cold
currents.    The surrounding  waters flourish with
rich marine resources.  In recent years,  however,
the problem of water pollution  has come very much
to the  fore.  Rapid industrial and economic develop-
ment of the province,  the  concentration  of  urban
life, and the mushroom growth of plants and factories
have combined to  cause, in some areas, the disposal
of urban refuse and industrial wastes to become serious
threats to  public  health and aquatic life.   In some
harbours the  dumping  of all oil wastes from ships
has  resulted in toxic effects on aquatic organisms
either  directly  or indirectly.   It  is reported that
the industrial wastes in Taiwan contain large amounts
of copper,  sulphur,  zinc, and harmful organic sub-
stances.  It is  also  contended that the destruction of
the  habitat, with  the   elimination  of  plankton and
bottom organisms is partly responsible for the decline
in coastal fishery products in recent years.


   Below  are some of  the  scourges   that are af-
fecting  Taiwan  fisheries with  increasing intensity.

   I. Kaohsiung Bay.

      Oysters flourish well on sandy flats in Kaohsiung
Bay.  In 1952, however, green oysters began to appear
at certain  locations  in the Bay.   When  eaten they
cause  vomiting and diarrhea,  the  symptom of food
poisoning.   To  reduce  the poison, the fishermen put
the oysters in  pure water and  washed out a certain
amount of the green substance.  The freshness and the
firmness of the oyster, however, were  lost with the
washing.  The  oyster price  dropped, but the demand
dropped  still  further;  almost  to a vanishing point.
   According to the report of  the  Taiwan Fisheries
Research Institute,  green oysters first appeared at
Linyar Liao of  Kaohsiung in 1952.  The wild oyster
became green first.  In  1954 green oysters were found
in  the  oyster  culture  beds in  the vicinity  of the
electric  power  plant and fertilizer factories.   By
1955, excepting the  areas of Hon Mao Kung and Chi
Juin where the tidal  current is comparatively strong,
all the oyster beds  in  Kaohsiung Bay were affected.
The price  of the green oysters dropped to only half
of  their  original  price.    Statistics   of  the local
fishermen's  association show  the value  of annual
oyster production in the above-mentioned areas at
about  a  new total of $5.4 million.  In consequence
of the declining demand after water pollution, this
figure fell to a new total of $2.7 million.  This resulted
in serious  hardship to the livelihood of the coastal
fishermen, brought about a cessation of oyster culture
in those areas, and adversely affected all related
crafts and craftsmen.
                               Two  factors  are responsible for the greenness
                            of  oysters:  (1)  absorption  and storing of  abundant
                            microorganisms  (e.g.  Navicula ostrearis) in  the
                            gills and intestines of oysters;  (2) excess of copper
                            salt (e.g.  CuSO4) in the water of oyster beds. Green
                            oysters  due to  factor (1) are unharmful, edible, and
                            delicious  tasting.   They are also  found and  eaten
                            in  Europe and  America.   However, oysters which
                            are green due to accumulation of copper salts  are
                            poisonous.   Upon  testing  of specimens from  the
                            Kaohsiung Bay,  it was  found that  the green oysters
                            contained  much green  substance  in their cells  and
                            tissues.   However, no  green microorganisms were
                            observed in their digestive tract.

                               By applying the Borax ball flame test, it was found
                            that most of the green  substance  was a copper salt.
                            The copper content in the green  oysters of Kaohsiung
                            Bay  was  found to  be   1,180 mg/kg, while copper
                            content  in ordinary oysters is only about 5.6 mg/kg.
                            Thus  the  oysters from Kaohsiung Bay contain over
                            200 times as much copper as normal oysters.

                               Kaohsiung  Bay  is in the shape of a  large bag
                            with a narrow mouth. Numerous factories and plants
                            have been set up along the inner  shore line. Under
                            the present  conditions  tremendous amounts of in-
                            dustrial  effluents  containing  a  considerable amount
                            of  copper salts  are being dumped into the harbour.
                            Hence,  it can  be  confidently  inferred  that  water
                            pollution  is  the  chief  cause of the scourge  to the
                            oyster beds in Kaohsiung.
                               II. Tainan Coast.

                                  The effects of pollution on fish along Tainan
                            coast were  first  brought to notice in 1960.  It was
                            reported that the  effluents  from some local paper
                            mills were  causing marked damages  to aquatic life
                            in the vicinity.

                               Analysis  of the water taken therefrom showed that
                            the effluents contained much sodium hydroxide, paper
                            pulp,  and some  strong acids.  The sodium hydroxide
                            has a direct  harmful  effect on  fish and shellfish,
                            and the  paper pulp  chokes  the fish gills.  Another
                            component,  hydrogen sulphide, is very poisonous to
                            fish and harmful to their growth.
                               III. Shaokang Area, Kaohsiung Hsien

                                  Shaokang is an important industrial  center in
                            southern Taiwan.   The industrial effluents from the
                            sugar factories and paper mills have become seriously
                            detrimental to fisheries in this area.
 National Taiwan University, Taipei, Taiwan, Republic of China.

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                            Effects of Pollution on Oysters and Fish in Taiwan
                                               369
   The analyses of the effluents have been conducted
by the Taiwan Fisheries Research Institute, and the
findings are tabulated as follows:
measures in dealing with water pollution:  (1) strength-
ening  of  study  and  research  on  the  problem of
pollution;  (2) insistence  on  the  proper  design  for
No. of sample
1

2


3

4
Location
of
sampling
Sea water
(100 m from
shore)
Mixture of
effluents and
sea water
Effluents from
sugar factories
Effluents from
paper mills
PH
value

7.2


7.4

7.2
7.2
Odor

-


H2S

Methane
Pulp
odor
Organic
substances
(Kubel Method)

0.97 g/1


1.14

37.33
2.85
Hydrogen
sulphide
12 Method

4.88 mg/1


8.17

7.16
5.21
Dissolved
oxygen
(Winkler Method)

3.53 cc/1


2.40

0
3.38
   The  above-mentioned  statement  is  intended  to
show the  detrimental  effects of pollution on fish and
oysters in Taiwan during recent year sand the growing
seriousness of the problem of pollution.

   The  following are  recommended  as   effective
effluent equipment of  all plants and factories before
approval  is granted;  (3) strengthening  of  effluent
control of  factories  already  established;  and  (4)
strict  prohibition  of  the  dumping of oil and other
wastes from  ships into harbour and inland  waters.

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                                SUMMARY OF THIRD SEMINAR

                                Richard H. Stroud and Charles H. Callison
   In an  attempt to give our summarization direc-
tion,  we asked ourselves:  What is  the purpose, or
function,  of a seminar in a given area of scientific
endeavor? The purpose  is multiple because several
answers can be given.   The seminar is a device for
becoming up-to-date: for discovering what is being
done  and what  has  been found out by other workers
in other institutions, in other lands,  and in related
fields of study.  It  is an opportunity for the exchange
of technical data and of information about new tech-
niques  and  equipment.   It is  a place for mutually
helpful  questioning  and criticism:  the mass applica-
tion,  so to speak, of the principle that two or more
heads are better than one.

   The  seminar also offers a medium for the identi-
fication of trends, new needs,  or new directions for
investigation and for the discernment of blind alleys
from which  research must  turn in its never-ending
quest for the roads to  truth.  Much must continue to
be said for  the  essential value of basic research;
but,  at  the same time  the total research effort has
an inevitably pragmatic  cast,  particularly when it
is dictated by  a  massive social and economic  need
such  as the world wide problem of water  pollution.

   It  was appropriate that this  seminar devote some
attention to  what might be called the "environment of
research."   We  refer  to the social,  economic, and
political factors that affect your jobs, your appropria-
tions, and your  opportunities to work.

   Finally,  the  seminar offers an opportunity for
generalization,  and in this summarization we  are
attempting in a way to be generalists.  We have tried
to express  some  general conclusions, all of which
you may not agree with but which may stimulate you
to do some  general thinking of your own  in a search
for more valid conclusions.

   Most of you are specialists in a  rather narrow
field  of science.  It is said that as  scientists become
more specialized they lose the ability to communicate
successfully  with specialists in  other fields.   And
what  may prove a more serious handicap, they lose
the ability to communicate  with the public and with
the politicians and administrators, in both industry and
government, who by the very nature of their jobs are
required to be pragmatists and to possess, or develop
to a high degree, the mental outlook and skills of the
generalist.

   The  public, the politicians, and the administrators
are the  ones who create the "environment of research. *
They use, or fail to use, the findings of the research
specialist. They provide the money and the facilities
for your training and your  work.  These facts were
recognized by the organizers of  the seminar program.
The   opening speech  was  delivered  by  James M.
Quigley, Assistant Secretary, U.  S.  Department of
Health, Education, and  Welfare, whose career has
illustrated the  importance of the generalist in our
society.    He  has been  a successful politician,  a
member of Congress, and now his work includes the
administration of the federal responsibilities in water
pollution control.

   The  Monday morning panel was  composed of ad-
ministrators and generalists, and their subject was
how the findings of research are being used, or can
be  used,   in  keeping  waters fit  for human uses.

   We shall undertake to point out some of the signi-
ficant thoughts and problems expressed in the panel
on  water  quality criteria.   Next,  we shall  try to
summarize the other panels and record some im-
pressions  of the concurrent, informal  dicussions.
We regret that it was physically impossible for two
people to  sit in on all  of them.  And, we beg of you,
please do not infer any slight or intentional oversight
if we fail to mention your name or your paper.  The
time available for this summarization and the physical
format  of the seminar  made it impossible to include
all of the splendid papers that truly deserve recogni-
tion.   Some omissions are due simply to the fact
that  not  all of  you  submitted  copies  or digests in
advance.

   This summarization is the best effort, in a limited
time, of only two people.  When the transactions are
published, we urge each of you to read them in full
and  form your own  conclusions.   A far better job
than this  one—and a more valuable  job  to each of
you personally—can be done at your leisure.

   Finally, we shall  undertake  some  general  con-
clusions and observations.   The emphasis of Secre-
tary Quigley's speech  should have special  and en-
couraging  significance  to  this  particular group of
professionals.   The problem of water pollution, he
said,  is broader than its public health aspects.  This
may  not  sound  new  to you,  but  its  utterance is
significant in view of some jousting now going  on in
Washington and some other places.

   The  uses man makes  of water  are mostly bio-
logical  and, therefore, the concern  of biologists.
Your approach,  he recommended,  should be  eco-
logical, and  you can help  by continually stressing
that  it is  not the average but the extremes of condi-
tions that are  important and are the true measures
of the suitability of an environment.

   He pointed out that on the basis of new legislative
authorizations  for research and enforcement  that
have not yet come  to fruition the politicians in  Con-
gress  have  been  ahead  of  the doctors,  lawyers,
engineers, and scientists  in the recognition of the
                                                   371

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 372
                                                Summary
massive  effort  that  must be  mounted to overcome
pollution.   This must mean  the  public is taking the
lead,  and if this is so, it is a most healthy situation.

   Finally, the Secretary signed up the biologist as
a  regular  member of the team—something none of
you  here has had any doubts  'about  although others
may be inclined to relegate you to the minor leagues
—but he  warned  it  is up to  the biologist to decide
whether he becomes  a star  or proves merely  to be
a bench warmer.

   Opening the panel on water quality criteria, Mr.
Murray Stein,  whose reputation for vigor and skill
in federal enforcement actions  has been justly earned,
expressed  the  opinion that  criteria, like time and
the tides, are inevitable.  In later  discussion, how-
ever, he  seemed to  reveal  some  personal doubts
about them.

   "We should guard," he said, "against the develop-
ment of  criteria becoming  the main  goal  of our
professional  life."    Your summarizers prefer to
interpret  this  statement as meaning that Mr.  Stein
believes that, pending the development of scientific
criteria, the administrators and policymakers should
not use the absence  of such criteria as an alibi for
postponing action on  flagrant  cases  of pollution that
should be cleaned up now through enforcement action.
Dr.  Tarzwell,  of  course,  emphasized at several
points along the way that criteria should be developed
on the best available basis and refined later.

   Michigan's  "old pro" administrator, Mr, Milton
P.  Adams,  sees water  quality criteria  most  useful
as administrative aids and in comprehensive planning
as authorized  by Section 2  (a) of  the  Federal Act,
but  of  doubtful usefulness  in  enforcement.   The
administrator,  he  said,  needs criteria  not just for
the protection  of aquatic life  but for all lawful uses
of water.

   Mr.  Weston's  contribution was   a forthright and
understandable  exposition of the  point of view  of the
industrialist.    Criteria are  absolutely necessary,
from this point of view,  in order that industry may
know what is expected of it.   He did not  discount the
possibility that  corporation executives may challenge
and  dispute such criteria as are finally developed by
public agencies, and he explained  why it must be
the policy of management to  keep  expenditures for
waste  treatment at  the  minimum  and  to postpone
such expenditures as  long as possible.

   Mr. Kimball presented an equally forthright state-
ment of the viewpoint  of the conservationist, who
calls for the  speedy development of scientific criteria
as essential to an effective attack on pollution.  There
is no  water problem too difficult,  he  believes,  if
research  is  given adequate manpower,  money, and
the other tools to tackle it.

   The discussion that followed,  including some ex-
cellent  contributions  from  the  floor,  was sharp,
interesting, and divulged wider  cleavages in philos-
ophy  than  may have  been apparent  in the prepared
statements of the panelists.
   Now turning to the other panels:   At the present
time, the environmental requirements  of most aquatic
organisms,  for  protozoa  and algae to  fish,  in both
fresh and salt water, are poorly known at best.  Only
the broad parameters of the  more obvious environ-
mental  factors  such  as dissolved oxygen  content,
pH, temperature, salinity, and a few others have been
assesed  for rather restricted numbers of  species,
generally as single  variables  rather  than as multi-
variates.    For  the most part, emphasis has been
placed on  lethality  over  short periods of time  in
terms of averages.  Yet, the consensus of the panelists
seemed to  be that  an ecological approach, empha-
sizing multivariate  relationships, is needed.  It was
recognized that an animal, or species, or community,
can  as  surely be  destroyed by gradual  change of the
environment in subtle ways as by sudden development
of directly lethal conditions.

   The  use of  averages  is  important  for  general
understanding  of quantitative  data,   of  course,  but
the  average  of  environmental conditions is not  a
measure of the suitability of an environment.  Rather,
as Mr. Quigley pointed out, it is the extremes that are
important  and yield the true measures. Much work
needs to be done in this area.

   In this   respect,  the paper by Mr.  Alderdice  on
multivariate  analysis of experimental environments
was particularly  pertinent.    Only in  this way can
precise definitions  of pollution be developed that will
be  meaningful in pollution abatement work, whether
it be  treatment of wastes or  enforcement of laws.
Mr. Adams had complained on Monday of the frequent
inability to make antipollution  laws work because of
a lack  of precise  definitions and  pointed  to  the
biologists  as the ones best equipped to secure  the
needed answers.   Mr.  Alderdice  holds—we believe
correctly—that   such answers are relative.   With
reference  to  such questions as:  "How much oxygen
does a fish need?"  or "What is the highest concentra-
tion of a. particular  pollutant that may be tolerated?",
he  states that the answers are "relative to the other
factors  and  their  levels that may be impressed
simultaneously on the particular animal considered."
Various combinations of levels of the factors serve
to impose  lesser or greater stress in the presence
of a pollutant. Better comprehension of the functional
capacities of organisms to meet environmental changes
should result from the multivariate approach.

   Microorganisms  capable of converting, into useful
products, the waste organic materials making up the
residue  of so-called complete treatment processes
are  badly  needed to save part of  the vast quantities
of dilution  waters now required. Mr. Kimball pointed
to  the profligacy of precious water inherent in our
present  lack  of knowledge  along these lines.  Dr.
Hutner, in  a  remarkably lucid and provocative lec-
ture, cited the need for mlcrobial  degradation  of
many  pollutants  and suggested an approach through
research on photosynthetic bacteria.

   Much emphasis  was placed on the  utilization of
various forms of plant  and  animal life as "indicator
species."  This method has been used with considerable
success to suggest the need, or lack of need, for

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                                             of Third Seminar
                                                                                                       373
intensive  studies.   Various  specialists pointed  out
both advantages and limitations of this approach.  At
the same time,  much emphasis was  placed on  the
need  for  specific  information on water quality re-
quirements.  For example, the insect panelists were
unanimous on this point, being able to cite few ex-
ceptions  and then  only for the more  perceptible
factors.

   Dr. Fjerdingstad's paper on a  new saprobic system
(particular reference to algae) was especially cogent,
suggesting more attention be paid to  community as-
pects of  organisms.  He  suggested that community
formation must be analogous to optimal living condi-
tions  of the species and that this  may be more sensi-
tive than the conventional use of indicator species,
the individuals of which have wide  tolerances.  The
presence  of vitamins and other organic compounds
must be accounted for as well as temperature, nutrient
salts, etc. Various metabolites that may be released
from  algal cells exert a variety of biological effects
upon other organisms.  Dr. Fogg discussed the role
of glycolic acid as a necessary factor for the growth
of Chlorella  and other microorganisms. Dr. Gorham
showed that the  development of  a toxic  waterbloom
depends  upon the  favorable  interaction of at least
six variables.

   A  review of the literature on environmental re-
quirements  of shrimp by Dr. Broad established that
the requirements are poorly known, that there is an
acute need for physiological research, and  that many
insecticides  are highly toxic to shrimp.  Dr. Butler's
work  of  more than a  decade on a population of com-
mercially unexploited oysters in a northwest Florida
estuary  revealed that apparently subtle  and largely
unidentified  environmental factors  may drastically
alter  the  character and quality of oysters.  Signifi-
cant multivariate studies by Dr. John D. Costlow, Jr.,
of the influence of three or four enviornmental factors
on  crab  development also  suggest both the complexi-
ties and the urgency for delineating standards of water
quality for marine organisms.   This  work points to
the possible use of crab larvae  as bioassay animals
for studies  of  marine water quality  and  pollution.

   Mr. Pentelow noted that the characteristics of the
aquatic environment undergo gradual natural change,
but that  man affects the nature of such changes.  We
must  live  with modern  developments  and do  the
research that will permit evaluation  and abatement
of the effects of those developments.  He  cited  the
discharge of waste heat into rivers and of substances
directly  toxic  to fish and  other organisms.  Drs.
Doudoroff  and Warren described  effects  upon fish
embryology,  growth,  and  certain aspects  of physi-
ology, of different dissolved oxygen concentrations,
temperatures, and water velocities.  They also dis-
cussed  the  need for research  into  the ecological
significance of these requirements of fishes and some
of  the problems  involved in these and  other water
quality requirements, most of which are poorly known
at best.   Dr. Bennett confirmed this for centrarchid
basses.   Dr. Huet stated that  relatively  clear-cut
criteria  can be expressed for temperature,  dissolved
oxygen, and  pH  for  only  a  few  species of fish.  He
said,  "The results of many  past experiments (about
the toxicity of various substances in complex water)
are of little use because the composition of the water
with which they were carried  out  is  not known."

   The modern  agricultural, industrial, and recrea-
tional pollutants inject new dimensions into the water
quality picture.  Unfortunately, little is known quanti-
tatively about either  their acute or chronic effects.
The  toxicity  to fishes of such substances as syn-
thetic detergents (Vivier and Nisbet), outboard motor
exhaust wastes (Surber,  English, and McDermott),
oil pollution  (Erickson),  heavy metal salts (Lloyd),
salinity (Kinne), and  organic insecticides (Nicholson)
is further  evidence   of the  need for polyfactorial
analyses in evaluation of water quality criteria.  Mr.
Lloyd  stated  the  need well:  "The  ultimate aim of
laboratory bioassays  is  to enable one  to predict a
concentration  of poison or effluent that must not be
exceeded  in  a  river  if fisheries are to remain un-
harmed... the   measure of toxicity  used has been
the lethal  threshold  concentration, since this value
can be  accurately determined,  but  more informa-
tion is required of sublethal  effects that may result
in a  gradual  deterioration of the condition  of  the
fish. ... It is only by a more complete understanding
of the basic  mechanisms involved  in  the relation
between  the susceptibility of fish to poisons and to
changes  in the environment  that any real advance
can be made."

   Since   World War  II a  whole  new  spectrum  of
pollutants—the  radionuclides—has appeared in sur-
face waters  as a  result  of  the  production and use
of fissionable  materials.   A number of these ele-
ments are naturally  present in aquatic environments
but are now increasing.  Discussions here revealed
a general paucity of  information concerning this new
field of inquiry. Limited observations by Dr.  Ravera
on normal radionuclide content of freshwater organ-
isms  and  sediment  in Lake   Maggiore  in northern
Italy revealed widely differentvalues of manganese-54
in mussels in  different zones.  Uptake and retention
of the radioactive  contaminants by marine plankton
could be postulated only on theoretical grounds, ac-
cording to Dr.  Lowman.  Mr. Price reported a few
mollusks  may  accumulate  at least  some radioiso-
topes in  all parts of the  body  and exoskeleton in
amounts   that  vary  with both the nuclide and  the
species involved.   Several  years work on Hanford
reactor effluent and receiving waters of the Columbia
River have resulted in an outline of some parameters
of the relationships between radionuclides and some
species of invertebrates and  of fish,  as reported by
Dr. Davis and by Dr.  Foster  and  Mr.  McConnon,
respectively,  but  this  area  of  inquiry  is  in  its
infancy.   In such work, a large number  of samples
taken over at least a full year is needed, because of
great variability in uptake of radionuclides by fishes,
to yield  an  estimate of  the average  radionuclide
concentration  in fishes and a  picture of the fluctua-
tions with time. For  muscle tissue of Rocky Mountain
whitefish,  seasonal variations in the concentration of
phosphorus -32 are  on the  order of  50-fold,  and
that of zinc -65, 10-fold.  Concentration factors in the
whitefish   ranged  from  zero  to  5,000  times those
found in  water for  phosphorus-32 and  up to 1,000
times  for zinc -65.   Both phosphorus  -32 and zinc

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374
                                                Summary
-65 are  present  in relatively low concentrations in
the river  but,  being  biologically  important,  are
dominant in the fish.   In contrast,  the really abun-
dant nuclides  in Columbia River water  (Chromium
-51, arsenic -76,  and neptunium -239) are relatively
unimportant in fish.

   Again, we  wish to  express  our  regret that it is
neither possible  nor appropriate  to discuss  all the
fine papers that were  presented  in the  stimulating
concurrent sessions.  Among them, however, we noted
with particular  interest  that Dr.  H. B.  N.   Hynes
advanced the thesis that low levels of pollution can
be  rapidly detected by determining the  numerical
makeup  of  the macroinvertebrate  population in  a
stream.   For  example, a gross  initial survey  that
shows  a decline in numbers of plecopterans  and an
increase in ephemeropterans  in  a British  stream
as one moves downstream indicates a pollution source
near by  and suggests the extent and magnitude of its
effects.   By quantitative  serial  sampling, done on
the  same  type  of substrate  for comparison,  Dr.
Hynes  noted that relative numbers of  the two in-
vertebrates gave clear  evidence of biological  altera-
tion even where pollution was slight.

   Dr. Cope pointed out that methods of analyses of
many  herbicides by  chemical  techniques  have not
yet been devised. Presentbioassay methods determine
toxicity  only semiquantitatively, by comparing stand-
ard growth  or  mortality   curves.   The accurate
measurement  of  pesticide  quantity appears to be
vital to the proper determination of toxicity patterns.
Many difficulties are encountered in laboratory anal-
yses.   Highly  variable results are  obtained when
individual animals are tested.   To understand and
predict  the effects of a pesticide on  fish, one must
know how its  action is affected by  water hardness,
alkalinity,  pH, and other factors; what its effect is
on  fish-food  organisms;  what the  differences in
chronic  and  acute toxicity  are;  and other factors.

   The problems posed by pesticides are many and
complicated, and the research  that needs to be done
is  of  staggering  proportions.   For  example,  Mr.
Bridges  reported that  in measuring  the  toxicity of
heptachlor and  keptone to redear sunfish (Lepomis
microlophus) changes in  resistance of the same lot
of  fish  occurs  during  the  holding period, and dif-
ferent lots  of the same  species  of  the same size
exhibit great differences in resistance under identical
conditions.   Ranges in chemical  concentrations to
produce  different effects are very  narrow.

    Fortunately, some new techniques are being devel-
oped to  measure insecticides in water samples.  Mr.
Van Valin and  Dr. Kallman described  the  use of
small  quantities of carbon  (charcoal) for  absorbing
pesticides from water.  In practice,  1-gallon samples
of  water are  shaken  with  10 grams of  charcoal.
The charcoal is filtered off, briefly  air-dried, ex-
tracted,  and analyzed by paper chromatography.  Re-
coveries of 60 to 90 percent of heptachlor have been
achieved in the 25- to 500-microgram range.

    Dr.  Hoffman  stated that  pesticide pollutants can
be  controlled by federal and  state laws specifying
conditions  of use,  by supervision of pest-control
programs by trained and responsible operators, by
establishment of  pest-control  review boards,  and
by educational activities and "good public relations"
in connection with  the  general safe use of agri-
cultural  chemicals.    He emphasized the  need for
research to discover less toxic pest control compounds
or, more  desirably, nonchemical methods that would
obviate water pollution problems.

   Dr. Nicholson  reported that toxaphene  and the
gamma isomer of benzene hexachloride  (BHS)  were
detected  nearly  year-round in waters draining from
a  400-square-mile  river basin where cotton is the
main crop and  occupies only about 6  percent of
the  land  in  the  watershed in  any given  year.  He
stated that  occurrence  of  sublethal  quantities of
pesticides in surface waters  may be rather common
in areas of routine  pesticide usage.  The concentra-
tion   at which harm is  caused by  such pollutants
remains  to be learned since  evaluation  of chronic-
exposure  effects  at  low levels  is very difficult.
Much more  work in this area  is  critically needed.

   The need for  more  exact and  sensitive proce-
dures was stressed also by Mr. Burdick.   He cited
the needs for a system of screening chemical com-
pounds, improved information on synergy and antag-
onism procedures for post  mortem analysis, and
mathematical models permitting evaluation and cor-
rection for simultaneous  interaction between  com-
ponents of the toxic system.   The problems in fish
appear  to be much  more complex than  in  man.

   Dr.  Patrick  observed that the  general use of
pollution-indicator species has become  much  more
difficult  because  of  the  rapidly increasing number
of polluting  substances  that have very different
chemical  and  physical characteristics.   Further-
more, variations in the natural  environment  may
greatly influence population size of "indicator species"
or even their presence or absence.  The importance
of considering the structure of the whole algae com-
munity as well  as  the kinds composing it has been
emphasized in recent years.

   Dr.  Snieszko  and Dr.  Glenn  L,  Hoffman pro-
pounded  the  need  for  test fish of uniform  quality.
Parasitic, bacterial and viral diseases, malnutrition,
and  uncertain hereditary background, singly  or in
combination, can drastically affect the usefulness of
the  fish for bioassays.  They outlined  fish-disease
control by  drugs, breeding  of disease-resistant
strains, and  general sanitary measures.  They noted
the  inadequacy of these measures and proposed the
establishment of "fish-breeding institutions" to pro-
vide  uniform, disease-free fish  such  as are now
available  to  supply  some laboratory animals; e.g.,
white mice, rats, and guinea pigs.

   Long-term studies of  the physiological responses
of aquatic animals to pollutants  were  urged in a
paper by  Dr. Fromm and in  the discussion  session
by  some  of his  colleagues at Michigan State Uni-
versity.   Dr. Fromm described an assessment pro-
cedure,  involving the  measurement of  oxygen con-
sumption  of  assay animals,  that is based on the
                                                                                              GPO 816-361 — 13

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                                             of Third Seminar
                                               375
assumption that no matter when environmental stress
is placed on an animal it will be reflected in a change
in normal metabolic rates.

   Dr.  Isaac  recounted the original development of
the  BOD  technique  by  the  Royal  Commission  on
Sewage  Disposal  (1898-1915)  and the  complicating
factors  introduced  by  high  suspended solids and
bottom muds.  The  Royal Commission  proposed the
standard of  20 ppm BOD  and 30  ppm  suspended
solids as  maximum for treatment  effluents, which
has  been almost  universally applied in England al-
though without statutory  support.  The BOD standard
has  fostered much research on the  fundamentals  of
aerobic stabilization of organic matter, but  relatively
little attention has been given to the suspended solids
standard.  Suspended solids and bottom muds interfere
with the BOD test and represent important  gaps  in
our knowledge.

   Your  summarizers moved  about  among the con-
current sessions  in a kind of sampling process;  and,
in general, we found the  discussions interesting, the
discussers  keen,  and the  give-and-take  free  and
frequently blunt.  We can understand why such sessions
have become a fixed feature of  this seminar.

   Among the recurring emphases and concerns ex-
pressed throughout the conference,  we see two  definite
and healthy trends.   The first is a turning toward an
ecological  approach in the  quest for new and  practi-
cable parameters  in  the  detection and evaluation  of
pollution and for  ways of combating it.  The  second,
a corollary of the first, is a movement toward  greater
dependence on field studies.

   There was a time when the classical biologists,
the  men who  controlled the  academic institutions
and standards, expressed  unveiled contempt for "field
research,"  brushing  its  findings aside  as  vague,
inexact,  and impossible of  controls,  and in the same
gesture brushing  aside those who would study nature
"in the raw"  as dreamers, as indolent piddlers, or,
the ultimate dismissal, as mere "naturalists."

   But all too frequently the  "laws" or "rules" or
calculations arrived  at in the laboratory failed mys-
teriously to work in the  rivers, as  was pointed out
here by  Dr. Kinne and others. Messrs.  Foster and
McConnon  made  a particular point  of the need for
field studies and for experiments that "closely simu-
late  field  conditions," because  there  are so many
variables,  and  so many  possible combinations  of
variables, in nature.

   The  turning  toward the ecological approach  was
reiterated  by  Dr. Cairns,  by Dr.  Broad,  by  Dr.
Erickson, by  Dr.  T,  T. Macan, and  by others whose
papers have already  been mentioned. The  questions
asked  by Dr.  Alderdice  and  quoted earlier  in  this
summary must also be asked  in other ways,  as what
concentration  of a pollutant may be tolerated for how
long? and with reference not to a particular animal
or plant but  to  a community  of  living organisms.

   These apparently  are the  things about the  life
sciences that  baffle and prompt the impatience of the
chemists and  engineers, whose disciplines are based
almost entirely  on conditions subject to precise con-
trol  and  measurement in a laboratory.  But if there
is a breakdown  of communications caused by a mis-
understanding of basic concepts between the chemists
and the biologists, there is a suggestion of the same
trouble between specializations in the life  sciences.
We trust it is only suggestive of such trouble that we
had here one  paper arguing for the use of the larger
invertebrates  as indicators of pollution, others pur-
suing the importance of the diatoms and other algae,
and still others stressing the aquatic insects or some
other group of organisms.  To the practical research
director  or program administrator,  it must  be ap-
parent that  each  of these methods is potentially
valuable  and each  must  be developed not as the only
key  but  as one  of a kit of tools that may be used,
singly sometimes but more  often in combination, in
the ultimate determination  of practical criteria of
water quality.  This was surely in Dr. Fjerdingstad's
mind as  he undertook to construct a "new saprobic
system."

   Then  we  heard  in this  seminar a  call,  almost
plaintive, for research  in depth  as  to time  as well
as  to  ecological  relationships.  The papers  by Dr.
Fromm  and Dr. Wilber, among others, suggest  the
need for advancement, at  least in the American re-
search world, beyond the  system of ad hoc research
and research by short-term grant.

   What  is  wrong with the system that finds  us only
now beginning the  most rudimentary research into
the  ecological  and  long-term side effects   of  the
synthetic organic pesticides full 2 decades after the
invention of DDT,  after  the  chemical pesticides  in-
dustry has  reached an annual sales  volume of $300
million in the United States  alone?  Who has failed
to meet  his responsibility?   We are still trying, on
meager budgets and with  a  mere handful of govern-
ment personnel,  to discover methods of detecting the
presence of these chemicals in water while concur-
rently, we may assume, industry is spending millions
in the development of new pesticides and other mil-
lions in their promotion and sales.

   "In addition  to money," said  Dr. Fromm in  his
pleading for long-term physiological studies in deter-
mining sublethal effects, "two things are needed for
research of  this type  to be carried  out:   (1) the
favorable attitude of administrators and (2)  trained
personnel to do the work."

   This brings us to some  concluding observations on
the subject of communications.  Communications is
perhaps  more  of  an art  than  a  science  but  any
scientist with average  intelligence and a  tongue in
his  head can master the  fundamentals of it.   We
speak of the need for research  biologists to learn
how to get their  story  across--to  each  other,  to
their bosses, to the legislators and boards of corpora-
tions,  and,  most  important  of all  in the  long run,
to the public.

   It is never too late in life, for example, to improve
one's speaking ability. The manner of the presentation
of papers here  ranged from very good to very poor.

-------
376
                                                Summary
One  does himself  and his profession  an injustice
•when,  in  making  a speech  or reading a paper, he
ducks his head and mumbles inaudibly into his shirt
front.

   Not every biologist can  be a gifted writer like
Rachel Carson, but any one  of you can take the time
and trouble  to make friends with the public relations
specialist in  your  agency or company and to  help
him  get your story to  the press.  Any biologist can
arrange  to  take administrators or  civic leaders or
newspaper  and magazine  writers  on  a tour  of the
laboratory or field project, letting them see with their
own  eyes the importance of your work.  These are
just a few of the methods that will work.

   We  shall  venture  the opinion  that the  current
article  in  Readers Digest about Dr.  Ruth Patrick
will  do more to assure continued public and financial
support for the work of the Philadelphia Academy of
Natural Sciences than all the papers presented at this
seminar by members  of the Academy staff.  Please
never,  through false modesty,  or genuine modesty,
or sheer inertia, or for other reasons, pass up an
opportunity  to  get similar publicity,  even  in your
home town newspaper.   And don't overlook the wis-
dom  of cutting your chief or your administrator in
on the publicity.

   It was a pleasure and a privilege to serve  as your
summarizers.  We hope all of you found the seminar
equally profitable.  The attendance itself, which we
understand from Dr.  Tarzwell was a record of 436
registrants, including participants from  26  foreign
countries,  augurs well for the future of  aquatropic
man.

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                                               ABSTRACTS
            ENGLISH

 THE  VALUE AND USE OF WATER
 QUALITY CRITERIA TO PROTECT
 AQUATIC  LIFE  IN STATE PRO-
 GRAMS.  Milton P. Adams, p. 7  .
 The value and use of water quality
 criteria for the protection of aquatic
 life are discussed from the point-
 of-view of a  state  administrator.
 The question is raised as to whether
 the use of water quality  criteria
 should be limited to the protection
 of aquatic life.  If the state adminis-
 trator needs criteria for the protect-
 ion  of  aquatic  life, criteria are
 needed  equally  for  the protection
 of  other lawful  uses of the water
 of his state.

   Most state administrators nec-
 essarily regard criteria or objec-
 tives  or  standards  as means of
 facilitating compliance with the state
 laws.  State laws with their varied
prohibitions or lack of  them do not
 contain  such things as water quality
 criteria.  Perhaps  this is  because
legislators do not understand such
 things as DO, BOD, and MPN, or
because of the widely varying con-
 cepts of what  water qualities are
injurious to public health.  In many
 cases,  water  quality  criteria set
up  as compliance aids  have failed
for one  reason or another to provide
 results.  Water quality criteria can
best be used as administrative rather
than as  enforcement aids, and to
implement  provisions  of the  law.

   The  interrelationship  between
federal, interstate, state, municipal,
and industrial efforts to obtain cer-
tain results through  comprehensive
programs for water pollution control
 clearly  require soundly conceived
 criteria that are susceptible of ful-
fillment. Lackofknowledgeimpedes
the development  and use of water
quality criteria for protecting aquatic
life.  Basic  and applied research
 is needed  to supply the enforcing
 igencies with solid answers to back
 ip  their position when restricting
 vaste loadings.
             FRENCH

 LA  VALEUR ET L'UTILITE^ DES
 CRITERES  DE  QUALITE D'DEAU
 POUR PROTEGER LA VIE AQUA-
 TIQUE EN PROGRAMMES D'UN
 ETAT.  Milton P.  Adams.
 p, 7                  La valeur et
 1'utilite des  criteres de qualite de
 1'eau pour proteger la vie aquatique
 sont  discutees du point-de-vue d'un
 administrateur d'etat.  La question
 est  posee si 1'emploi des criteres
 de qualite de 1'eau  pourrait etre
 limite li  la protection de  la vie
 aquatique. Si 1'administrateur d'un
 etat a besoin de ces  crite'res pour
 la protection de la vie aquatique, des
 crite'res sont egalement requispour
 la protection des autres emplois
 legitimes   de 1'eau  de  son etat.

   La plupart des administrateurs
 d'etat considerent necessairement
 les  criteres, ou  objectifs,  ou les
 madeles comme unmoyendefacilite
 conformement aux lois des etats.
 Les  lois  des etats avec leurs in-
 terdictions varient ou leur manque
 de celles-ci ne  contiennent pas de
 tel sujet  comme celui des criteres
 de qualites  de 1'eau.    Peut-etre
 c'est parce que les legislateurs ne
 comprennent  pas de tels choses
 comme DO,  BOD, et MPN ou parce
 que   vu la  conception  diverse  de
 quelques criteres de qualite d'eau ce
 serient nuisible a la sante publique.
 En beaucoup  de cas, les installations
 pour  la recherche des  criteres de
 qualite de 1'eau ont failli pour une
 raison ou pour  une  autre fournir
 des   resultats.    Les criteres  de
 qualite d'eau pauvent  mieux e*tre
 employes  sur le plan administratif
 au lieu de 1'employement des aides
 pour 1'execution des dispositions de
 loi.

   Les relations  entre  la Federal,
 1'entre-etat,  1'etat, les municipalitls
 et 1'industrie pour obtenir certains
 resultats a travers des programmes
 comprehensifs pour  la  contrSle de
 la pollution d'eau demande precise-
 ment des criteres  solidement concu
 qui sont susceptibles d'aboutir. Le
 monque de connaissance retarde le
 developpement  et  1'emploie  des
 criteres  de  qualite  de  1'eau pour
proteger  la  vie  aquatique.  Les
 recherches  elementaires et  appli-
 quees fournissent 1'agence d'execu-
 tion avec des responses solides afin
d'appuyer  leur position au sujet des
 restrictions de depot d'ordure.
            GERMAN
WERT  UNO  ANWENDUNG  VON
WASSERGUTEKENNZEICHEN ZUM
SCHUTZ DES LEBENS IN WASSER
IN STAATLICHEN PROGRAMMEN.
Milton P. Adams p. 7
Wert und Anwendung von Wasser -
giitekennzeichen  zum  Schutz des
Lebens im  Wasser   werden  vom
Standpunkt des staatlichenVerwal-
tungsbeamten  besprochen.     Die
Frage wird aufgeworfen, ob die An-
wendung soldier  Kennzeichen auf
den Schutz des Lebens im Wasser be-
schr'ankt  bleiben  soil.  Wenn der
staatliche Verwaltungsbeamte diese
Kennzeichen  fur den  angegebenen
Zweck  notig hat,  dann braucht er
gleicherweise Kennzeichen fur den
Schutz  anderer  gesetzlicher   An-
wendungen von  Wasser  in  seinem
Staate.

   Die meisten Verwaltungsbeamten
betrachten notwendigerweise Kenn-
zeichen,  Ziele oder  Normen als
Mittel zur Er lei enter ung der  An-
wendung der Staatsgesetze,  Staats-
gesetze mit ihren verschiedenen Ver-
boten  Oder der Abwesenheit von
Verboten enthalten solche Dinge wie
Wassergiitekennzeichen nicht. Viel-
leicht ist das darauf zuriickzufuh -
ren, dass Gesetzgeber Abkurzungen
wie DO, BOD oder MPN nicht ver-
stehen oder well die mannigfaltigen
Ideen liber Wassergiite der bffent-
lichen  Gesundheitspflege  schaden
konnten.  In vielen Fallen schlugen
Wassergiitekennzeichen,  die  zur
Erleichterung der Gesetzhandhabung
eingefiihrt worden waren, aus nicht
naher bekannten Griinden fehl. Sol-
che Kennzeichen  kdnnen  am best-
en als Behelfe der Verwaltung und
als zusatzlichegesetzlicheVerord-
nungen  beniitzt  werden,  nicht aber
fiir  polizeiliche  Massnahmen.
Die Beziehungen zwischenBundes -,
zwischenstaatlichen,    staatlichen,
gemeindlichen  und   industriellen
Bemiihungen  zur  Erlangung be-
stimmter Ergebnissedurchumfass-
ende  Programme zur  Kontrolle der
Wasserverunreinigung   verlangen
offensichtlich klar durchdachte und
praktisch  erreichbare    Normen.
Mangelndes Wissen hindert die Ent-
wicklung und Anwendung  von Was-
sergiitekennzeichen zum Schutz des
Lebens  in Wasser.  Grundlagen-und
Zweckforschung sind  nbtig, um den
Vollzugsorganen zuverlassige Anga-
ben an die Hand zu geben, auf Grund
deren  sie  Massnahmen  zur  Ein-
schrankung   der  Belastung   von
Gewassern durch Abflusse ergreifen
k6nnen.
                                                       377

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ANALYSIS   OF   EXPERIMENTAL
MULTIVARIABLE ENVIRONMENTS
RELATED  TO THE PROBLEM OF
AQUATIC POLLUTION.  D.  F.
Alderdice.  p. 320.  By means  of a
modified scheme of factorial
analysis, the  response  of terms
of  median  resistance  time in
minutes  of juvenile  coho  salmon
to 3 milligrams per liter of sodium
pentachlorophenate was investigated
over combinations of levels of salin-
ity  (°/ooS), temperature  <(°C), and
dissolved oxygen (mgO2/l),

   The data are fitted to a second-
order polynomial that  is reduced to
its  equivalent geometric  form for
evaluation of response surfaces in
the three-factor system. Hence, the
response to the pentachlorophenate
is

Yp  = 111.1478 + 6.9025 KX - 7.0395
    X2 + 2.4953 x3 - 3.8914 jq2 -
    14.5269 X22 - 7.3060 x32 -f
    0.4918 x^ + 0.1298 x^ -
    2.0013 X2x3

where xi,  x2, and x3 refer to the
coded variables  salinity, tempera-
ture and dissolved oxygen, respec-
tively, and geometric form.

  YD - 110.4030 = - 3.8852 X 2 -
   P  14.6689 X22 - 7.1702 X32

Xi, X2,  and X3 are functions of the
coded variables.

   A region of optimum resistance
time is computed with its center at
9.50°/ooS,  3.89°C,and5.92 mgO2/L
Loci on theellipsoidalenvelope sur-
rounding the optimum, at which 90
percent of  the optimum  response
would  be  retained,  are  computed
in terms of combinations of levels
of  salinity, temperature, and dis-
solved oxygen.

   Functional  capacities as meas-
ured experimentally are discussed
with reference to their significance
in  the normal  environment.   The
data indicate  that within  normally
viable limits  of the  three  factors
tested there are  combinations of
levels of the factors that  impose
lesser  or   greater  stress in the
presence of a pollutant.  The signi-
ficance  of  this  fact  is  discussed
with reference to  the problems of
definition of the biological effects
of water quality alteration, and the
interpretation of such changes in the
polluted environment.
 ANALYSE DBS MILIEUX EXPERI-
 MENTAUX A PLUSIEURS  VARI-
 ABLES PAR RAPPORT AU PROB-
 LEMS  DE  LA  POLLUTION  DES
 EAUX.   D.F. Alderdice.   p.  320.
 En  utilisant  une  modification, de
 1'analyse  factorielle, on  a  etudie
 les  reactions  des jeunes  saumons
 coho,  exprimees  comme duree de
 resistance  mediane  (en minutes),
 a 3  milligrammes  per  litre de
 pentachlorophenate de sodium.  On
 a etudie  ces reactions per rapport
 a des combinaisons de conditions de
 salinite  (°/oo S),  de temperature
 (°C),et d'oxygene dissous (mgOg/l).

   Un polynome du  second degre
 a ete applique aux  donnees  et  a
 ete reduit a une forme geometrique
 equivalente  pour 1'evaluation des
 surfaces  de reactions  dans   un
 systeme a trois dimensions. Ainsi
 la reaction au pentachlorophenate est
 Y  = 111.1478 + 6.9025 x<  - 7.0395
    x2 + 2.4953 x3 - 3.89H x:2 -
    14.5269 x,2 - 7.3060 xg2  +
    0.4918 XjX2 + 0.1298 x^ -
    2.0013 X2x3
 ou xi, X2, et xs representent les
 variables  (exprimees en code) sa-
 linite,  temperature,  et oxygene
 dissous  respectivement,  dont  la
 forme geometrique est
  Yp - 110.4030 = - 3.8852X12 -
      14.6689X22 - 7.1702X32
 ou  Xi,  X2,  et  X3 sont  functions
 des variables x-^, x2, et x3.

   La  region  de la duree maximum
 de resistance a ete calculee comme
 ayant  son  centre a  9.50  °/oo S,
 3.89°C,  et 5.92  mg  O2/.1.   On a
 ainse^  calculi  sur  1'enveloppe el-
 lipsoidale autour du point maximum
 les lieux geometriques de 90% de la
 reaction maximum.   Ces lieux ont
 ete exprimes comme combinaisons
 de niveaux  de salinite, de tem-
 perature, et d'oxygene dissous.

   On discute les capacites fonction-
 nelles  des poissons mesurees ex-
 perimentalement et leur signification
 dans un milieu normal. Les donnees
 indiquent ceci: en dedans des limites,
 normalement non fatales, de chacun
 des trois facteure etudies, il yades
 combinaisons  de  concentrations de
 ces facteurs qui causent des tensions
 plus ou  moins fortes en presence
 d'un agent polluant.   On discute de
 la portee de ce fait sur une defini-
 tion  experimental des effects bio-
 ligiques  de 1'alteration  des  prop-
 rietes de 1'eau, etdel'interpretation
de tels changements dans un milieu
pollue.
ANALYSE VON MEHRFACH VER-
ANDERLICHEN    VERSUCHSFEL-
DERN  UNO DAS  PROBLEM  DER
WASSERVERUNREINIGUNG.   Don
F. Alderdice.  p. 320
Durch ein abgeandertes Schema der
Naherungsanalyse  wurde die Reak-
tion  von Cohe Salmsetzlingen (aus-
gedriickt in mittlerer \yiderstands-
zeit in Minuten) gegenuber 3 milli-
gram  per Liter   Natriumpenta-
chlorphenat in Verbindung mit Sal-
zgenhaltstufen (O/oo S),Temperatur
(  °C.   )  und  gelostem  Sauerstoff
(Milligram per Liter) studiert.

   Durch  geeignete mathematische
Behandlung der  Ergebnisse erha.lt
man fur  die Reaktion auf die An-
wendung von Pentachlorphenat Yp =
111,1478  +  6,9025xi  - 7,0395x9 +
2,4953x3 - 3,8914x12' - 14,5269x22 -
7,3060X32 + 0,4918xix2 + 0,1298xix3
-  2,OOl'3x2X3>worin x-^, X2, x3 die
Veranderlichen Salzgehalt,   Tem-
peratur  und  gelosten   Sauerstoff
bedeuten und die geometrische Form
YD -  110,4030 =  -  3,8852 X].2 -
14,6689 X22 - 7,1702 X32. Xj, X2)
Xs sind Funktionen der Verander-
lichen,

   Ein  Gebiet bester Widerstands-
zeit wird errechnet  mit dem Mit-
telpunkt bei 9,50%0S, 3,89°  C. und
5,92  mg  O2/l.    Orter auf  der
ellipsoiden Einhlillenden  um  den
Bestwert,  wo  noch  90% des Best-
werts  herrschen, werden fur Stufen
des  Salzgehalts,  die  Temperatur
und den gelosten Sauerstoff ausge-
wertet.

   Experimentell gemessene Werte
von Fahigkeitenwredenunter Bezug-
nahme  auf ihre  Bedeutung in  der
normalen  Umgebung  besprochen.
Die  Ergebnisse  zeigen,  dass  es
innerhalb der Grenzen der drei ge -
priiften Faktoren Kombinationenvon
Stufen der Faktoren gibt, welche in
Gegenwart  einer  Verunreinigung
dem System einen mehr Oder rain-
e'er grossen Zwang auferlegen. Die
Bedeutung dieser Tatsache wird im
Zusammenhang mit den Problemen
der Definition biologischer Wirkun-
gen auf Veranderung der Wassergiite
und der Erklarung derartiger Veran-
derungen in  einer  verunreinigten
Umgebung besprochen.
                                                       378

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AN EXPERIMENTAL ANALYSIS OF
THE FACTORS RESPONSIBLE FOR
THE  PERIODIC  MORTALITY OF
TILAPIA MOSSAMBICA PETERS IN
BUSHVELD RESERVOIRS  IN THE
TRANSVAAL.    B. R.  Allanson,
M. Ernst,  and R. G. Noble, p. 293.
The cause  of  periodic mortality
among fish in the  dams of the bush-
veld - highveld transition region in
the  Transvaal, South  Africa,  has
been investigated experimentally in
the laboratories of the National In-
stitute for  Water Research and the
Department of Nature Conservation,
Transvaal  Provincial  Administra-
tion.

   Many of these dams receive ef-
fluent  from sewage works  and in-
dustries via the  inflowing rivers.
Both these sources have been blamed
for the periodic mortality, especially
among individuals of T.  mossambica.
But  the fact that such mortalities
were more frequent during  the cold
dry winters suggests that decrease
in  water   temperature during the
winter might play a more important
role than the effluent discharge into
the catchments of  the dams.  To
this end both the high temperature
and low temperature tolerance and
resistance  of T, mossambica  have
been investigated.

   Studies  have shown that  T. mos-
sambica  is capable  of very rapid
acclimation to high temperatures
and that the ultimate  upper  lethal
limit  is  slightly  above 38 °C.  On
the other   hand acclimation to  low
temperature is very slow and as yet
no ultimate lower lethal temperature
has been measured.  This slow ac-
clamation  to  low  temperatures  is
also linked with a high sensitivity
to such temperatures  (between 8°-
15 °C), depending upon  the total dis-
solved  solid  concentration or os-
motic pressure of the water during
the exposure. LDso estimates based
upon temperatures  that  initiate
secondary  chill  coma  indicate
clearly that the water temperature
obtaining in these dams during winter
is the  factor responsible  for  the
extensive  mortalities,   especially
among  the  small size group  (12
cm ) of this cichlid species.
ANALYSE  EXPERIMENTALE DBS
FACTEURSXRESPONSABLES DBS
MORTALITES  '^ERIODIQUES  DE
TILAPIA  MOSSAMBICA  PETERS
DANS  LES  RESERVOIRS DBS
TERRES BASSES AU TRANSVAAL.
B.R.  Allanson,  M.  Ernst, et R.G.
Noble.   p. 293 .    Les  services
administratifs provinciaux du Tran-
svaal ont organise des travaux afin
de determiner  la  cause de la mor-
talite apparaissant periodiquement
chex les poissons des barrages de
la region  de  transition entre les
terres basses et les  plateaux eleves
au Transvaal, Afrique du Sud. Ces
travaux de  recherches ont eteentre-
pris par les laboratoires de 1'Institut
National des Recherches aquatiques
et ceux  du ministere de  la Con-
servation naturelle,

   Des  eaux d'origine industrielle
et des  eaux  d'egoutssedeversent
dans  plusieurs  des  rivieres  qui
alimentent  ces  barrages.   On  a
blame ces deux  sources  de pol-
lution pour la mortalite qui semble
se produire periodiquement surtout
chex  les  individus  de 1'espece  T.
mossambica.  Toutefois, ces mor-
talites se  produisent plus souvent
durant les  hivers froids  et sees,
et ceci semble suggerer que la basse
temperature de 1'eau durant 1'hiver
jouerait un rSle plus important qui
le dibit des eaux polluees dans les
bassins de drainage en amont des
barrages.    C'est  pourquoi on  a
entrepris  des   travaux  sur  la
tolerance  et la resistance  de  T.
mossambica    aux  temperatures
elevees  et aux temperatures basses.

   Ces recherches ont montre que
T.  mossambica  s'acclimate tres
rapidement a  des  temperatures
elevles  et que la temperature maxi-
mum  fatale est un  peu au dessus
de 38°C. D'un autre cote, 1'accli-
matation aux temperatures basses
est tres  lente et on n'a pas mesure
a date une temperature minimum
fatale.  Cette acclimation lente aux
basses temperatures est aussi liee
a une grande^ susceptibilite a cer-
taines  temperatures (entre  8°  et
15 °C) selon la concentration totale
des sels dissous ou  de la pression
osmotique  de  1'eau  dans ces con-
ditions.   Des estimes  de  "LDso*
bases  sur  des temperatures  qui
amlnent le comadurefroidissement
secondaire indequent clairement que
la temperature de 1'eau des bar rages
durant 1'hiver  est le  facteur re-
sponsable  des  mortalites   nom-
breuses.    Ceci est  tout speciale-
ment  clair  chez les individus de
petite taille (12 cm.)  de cette espece
des cichlides.
 EXPERIMENTELLE ANALYSE DER
 FAKTOREN,  WELCHE  FUR DAS
 PERIODISCHE STERBEN VON TIL-
 APIA  MOSSAMBICA  PETERS  IN
 DEN BUSHVELD   STAUSEEN   IM
 TRANSVAAL  VERANTWORTLICH
 SIND.   B. R.  Allanson, M. Ernst,
 und R. G. Noble,  p. 293
 Die  Ursache  der  periodischen
 Fischsterben  in  den .Stauseen des
 Bushveld  -  Highveld Ubergangsge-
 bietes im  Transvaal,  Siidafrika
 wurde in  den  Laboratorien des Na-
 tional Institute for Water Research
 und des Department of Nature Con-
 servation, Transvaal Provincial Ad-
 ministration experimentell unter-
 sucht.

   Viele  dieser Stauseen  erhalten
 Abwasser von  Klaranlagen und In-
 dustrien.   Diese  beiden Ursachen
 sind fur  das  periodische  Sterben,
 besonders von Tilapia mossambica
 verantwortlich  gemacht  worden.
 Aber die Tatsache, dass diese Fisch-
 sterben w'ahrend der katen  trocke-
 nen Winter  haufiger sind, lasst
 vermuten, dass die niedrigere Was-
 sertemperatur im  Winter eine wich-
 tigere  Rolle als die Einleitung von
 Abwa'ssern  in die  Stauseen  der
 Damme  spielt.   Deshalb  wurde
 die  Toleranz  und  der  Wider stand
 von T. mossambica gegen hohe und
 niedrige Temperaturen untersucht.

   Diese  Studien  zeigten,  dass  T.
 mossambica  fahig ist,  sich sehr
 rasch auf hohe Temperaturen ein-
 zustellen  und  dass die obere Tod-
 lichkeitsgrenze etwas iiber 38°  C.
 liegt. Auf der anderen Seite ist die
 Einstellung  auf niedere  Tempera-
 turen sehr langsam und bisher konn-
 te  noch  keine allerletzte  niedri-
 gere tbdliche Temperatur gemessen
 werden.   Dieses langsame  Einstel-
 len auf niedere Temperaturen steht
 auchim Zusammenhang mit der ho-
 hen Empfindlichkeit fur diese Tem-
 peraturen  (zwischen 8 und 15 °C.)
 und hangt ausserdem von der Kon-
 zentration der gelosten Salze oder
 vom osmotischen Druck der Losung
 ab.  LDso Bestimmungen auf Grund
 der Temperaturen, welche  sekun-
dares Kaltecoma hervorrufen,zeigen
 deutlich,   dass   die   Wassertem-
peratur in diesen Stauseen im Winter
fur  d i e  zahlreichen Todesfalle,
besonders der Grossengruppe von
 etwa 12 cm. dieser   Cichlidenart,
verantwortlich ist.
                                                      379

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THE ENVIRONMENTAL REQUIRE-
MENTS OF  CENTRARCHIDS WITH
SPECIAL REFERENCE TO LARGE-
MOUTH  BASS,  SMALLMOUTH
BASS, AND SPOTTED BASS. George
Bennett,  p. 156 .  It is impossible
to define exact habitat requirements
for  any species of centrarchidbass.
As  with  most species of  fish, the
embryos and yolk sac fry are usually
much more  vulnerable  than  are
adults or advanced fingerlings to
unfavorable physical,  chemical, or
biological conditions in the habitat.
Laboratory experiments  indicate
that largemouth finger lings can with-
stand sudden  changes  in  pH,  and
excessively high and relatively low
levels of dissolved oxygen.   The
absence of bass in an aquatic habitat
may  indicate  unfavorable physio-
chemical conditions, but more often
it is an indication of unfavorable or
abnormal ecological interrelation-
ships.
 LES BESOINS DE MILIEU D.E CEN-
 TRARCHIDAE AVEC REFERENCE
 SPECIAL DBS MICROPTERUS
 SALMOWES, MICROP.TERUSDOL-
 OMIEVI, ET DBS MICROPTERUS
 PVNCTULATUS.   George Bennett.
 p. 156. II est impossible de definir
 les  besoins  exacts d'habitat pour
 aucune  espece des CentrarMdae.
 Pour le plupart  des especes de
 poissons, les embryons et les oeux
 sont ordinairement plus vulnerables
 que  les  adultes avanc«s, dans les
 conditions physiques, chimiques au
 biologiques defavorables de 1' hab-
 itat.  Les essais de laboratoire indi-
 quent que les types de saumoneaux
 Micropterus  salmoides peuvent re-
 sister en changements soudain de
 pH, et aux niveaux d'oxygene degagSe
 excessivement haut et relativement
 has.  L'absence des CentrarMdae
 dans un habitat aquatique peut in-
 diquer des conditions physico-chi-
 miques  defavorables  mais   bien
 sauvent  c'est une indication de
 rapport  ecologique defavorable ou
 anormal.
DIE ANFORDERUNGEN DER CEN-
TRARCHIDEN ANIHRE UMGEBUNG
MIT BESONDERER BERUCKSICH-
TIGUNG   GEWISSER  BARSCHE.
George Bennett,  p. 156
Die  Arbeit  beriicksichtigt beson-
ders Largemouth Bass,   Microp-
terus salmoides Lacepede, Small-
mouth Bass, Micropterus  dolomieui
Lacepede und Spotted Bass, Micro -
pterus punchdatus Rafinesque.

   Es erscheint unmbglieh, die An-
forderungen  irgendeiner  Art der
centrarchiden Barsche an ihre Um-
gebung genau festzulegeiu  Wie es
bei den meisten Fischarten der Fall
1st,  so  sind auch  hier Embryonen
und frvihe Entwicklungsstufen gegen
ungunstige physikalische,  chemi-
sche Oder btologische Umweltbedin-
gungen gewohnlich empflndlicher als
altere Oder erwachsene Tiere.  La-
boratoriumsversuche zeigen, dass
junge M.  salmoides plbtzliche pH
Anderungen und liber massig hohe wie
auch verhaltnismassig niedrige Kon-
zentrationen  von gelostem Sauer-
stoff auszuhalten vermogen.  Die
Abwesenheit von Barschen in einem
Gewasser  kann ungunstige physika-
lisch-chemische Bedingungen  an-
zeigen,  viel  bfter aber 1st sie ein
Hinweis  auf ungunstige  oder ab-
normale  okologische Verhaltnisse.
 EFFECTS OF TIME AND TEMPER-
 ATURE  ON  THE  TOXICITY  OF
 HEPTACHLOR AND  KEPONE  TO
 REDEAR SUNFISH.  W.R. Bridges.
 p. 247 .  The toxic effects of hep-
 tachlor and kepone were measured
 by the determination of the Median
 Effective Concentration (EC50),the
 concentration  required  to produce
 50 percent mortality of the fish at
 each  time and temperature tested.
 ECso values  for heptachlor ranged
 from  0.017 milligram per liter for
 96 hours' exposure at 75°F to 0.092
 milligram  per  liter for 6 hours
 exposure at 45°F; comparable values
 for kepone were  0.034  milligram
 per liter and 5.6 milligrams per
 liter.   The toxicity of kepone greatly
 increased with the time of exposure,
 whereas the influence of increased
 time  on the  toxicity of heptachlor
 was only moderate.  Higher tem-
 peratures caused  a  moderate  in-
 crease in toxic effects of both com-
 pounds.
LES EFFETS DE TEMPS ET DE
TEMPERATURE SUR LA TOXICITE
D'HEPTACHLOR ET DE KEPONE A
LEPOMIS MICROLOPHVS.  W.  R.
Bridges.   p. 247  .    Les  effets
toxiques d'heptachlore  et  kepone
etaient  mesures  par la determin-
ation de la  concentration  effective
mediane au  ECso  (concentration
exigee pour produire 50% de mor-
talite des poissons) a chaque essais
de temps et de temperature.  Les
valeurs  ECgo  pour  1'heptachlore
varient de  0.017 milligramme per
litre pour 96 heures d'exposition a
27°C.;  a 0.092 milligramme per
litre pour  24 heures  d'exposition
a  7°C.;  les  valeurs comparables
pour le kepone etaient 0.044 milli-
gramme per  litre et 0.62  milli-
gramme per  litre.   La  toxicit€
de  kepone   a beaucoup augmentee
avec le temps d'exposition, tandis
que  1'influence de la  longueur  du
temps  sur  la  toxicite' Stait seule-
ment moderee. Des  temperatures
plus hautes ont seulement pour effet
une  legere  augmentation en effets
toxiques pour les deux composants.
 EINFLUSS VON  ZEIT UND TEM-
 PERATUR AUF  DIE GIFTIGKEIT
 VON  HEPTACHLOR UND KEPONE
 GEGENUBER REDEAR  SUNFISH.
 W. R. Bridge,  p. 247   .  Die Gift-
 wirkungen von  Heptachlor  (1,4,5,6,
 7, 8,  8-hepta -  chlor-3x,4, 7, 7x-
 tetrahydro-4, 7-methanoinden)  und
 Kepone (Deka  -  chloroktahydro-1,
 3, 4-methano-2 H-cyklobuta CD  -
 pentalen-2-on) -warden durch Bestim-
 mung  der   mittleren  wirksamen
 Konzentration  (EC5o)  gemessen,
 namlich jener Konzentration, welche
 50% SterblichkeitdesRedearSunfish
 (Lepomis microlophus) bie  der  je-
 •weiligen Versuchszeit und Temper-
 ratur verursacht. ECso  Werte  fur
 Heptachlor   schwankten  zwischen
 0,017 mg/1 fur 96  Stunden Versuchs-
 zeit  bei 75°  F  (etwa 24°C)  und
 0,092  mg/1 fur 6 Stunden Versuchs-
 zeit   bei  45°F  (  etwa 8°C);  die
 entsprechenden Werte fur Kepone
 waren 0,034 mg/1  und  5,6 mg/1.
 Fur langere Versuchszeiten war die
 Giftigkeit von Kepone bedeutend gro-
 sser  als  aus den Ergebnissen  von
 kurzen Versuchszeiten zu erwarten
 war, wahrend der Einfluss langerer
 Versuchszeiten auf die Giftigkeit von
 Heptachlor nur  massig war. Hb'here
 Versuchstemperaturen verursach-
 ten geringe  Zunahme in der Gift-
 wirkung beider Verbindungen.
                                                      380

-------
 THE BIOLOGY OF  THE TUBIFI-
 CIDAE  WITH SPECIAL  REFER-
 ENCE TO POLLUTION. R.O. Brink-
 hurst,   p. 57  .   The  title of this
 paper is a little ambitious in relation
 to our knowledge  of  the biology of
 the  aquatic oligochaetes and of the
 Tubificidae in particular.  The sub-
 ject  is  reviewed,  however, under
 three headings: the establishment of
 physical  and  chemical  tolerance
 limits for  individual species;  the
 search for  indicator  species whose
 mere presence or absence can  be
 used to categorize the water con-
 cerned;  and  detailed  analyses  of
 community  structure, emphasizing
 identification to species.  Our frag-
 mentary knowledge under the first
 heading  is reviewed, but few if any
 conclusions can  be  drawn as  yet
 in view of the interaction of factors
 in nature, the variability of tolerance
 levels within the species in respect
 to different stages in the life cycle,
 and  other complications.  Under the
 second heading it is claimed that
 there is no such universal indicator
 organism  available,  certainly  not
 in  the  Tubificidae.   Finally,  the
 pattern  of  species distribution  in
 relation to  known sources of pol-
 lution in British rivers is described,
 and  the  hope is expressed that de-
 tailed surveys along such lines will
 clarify  this pattern and so render
 invertebrate surveys more complete
 and   more useful as  a diagnostic
 tool.
 LAx BIOLOGIE  DBS  TUBIFEX
 SPECIALEMENT   EN   RAPPORT
 A L'A POLLUTIONS. O.  Brinkhurst
 p, 57  .    Le  titre  de cet article
 semble un peu pretentieux quant a
 notre connaissance de la biologie des
 oligochetes aquatiques et des Tubif ex
 en particulier.  Toutefois le sujet
 est examine  de nouveau sous trois
 aspects:   (1)  etablissement  des
 limites  de tolerance physique et
 chimique pour  certaines especes;
 (2) la recherche pour trouver des
 especes  indicatrices dont la pre-
 sence  ou  1'absence suffirait pour
 definir la qualite de 1'eau en question;
 (3) des  analyses  detaillees  de la
 structure  des  populations  en in-
 sistant   sur  1'identification    des
 especes.   Nos  connaissances re-
 streintes du  premier aspect font le
 sujet d'un examen detaille,  mais
 i  date  il  est difficile d'arriver a
 des  conclusions d'abord a cause de
 1'action  combinee  de facteurs dans
 la nature, puis de  la variabilite des
 niveaux de tolerance pour une m§me
 espece,  a 1'egard des stages dif-
 ferents du cycle  vital  et aussi a
 cause d'autres complications. Quant
 au deiudeme point consider!, on
 croit qu'il n'existe aucunorganisme
 indicateur universel  de ce genre,
 du moins certainement pas chez
 les  Tubif ex.   Pour finir on  decrit
 la structure  de la distribution des
 especes  par  rapport aux  sources
 de  pollution   dans les  rivieres
 d'Angleterre.    On espere que des
 releves detailles dans le  meme sens
 pourront rendre cette structure plus
 plaire  et par  le fait  mime rendre
 ces  releves plus  complets et plus
 utiles  comme instrument diagnos-
 tique.
 DIE BIOLOGIE DER TUBIFICIDAE
 MIT BESONDERER BERUCKSICH-
 TIGUNG VON  WASSERVERUNREI-
 NIGUNGEN.   Ralph Owen  Brink-
 hurst,  p. 57    .  Die  ilberschrift
 dieser  Abhandlung  ist etwas  ehr-
 geizig mit  Bezug auf unser Wissen
 iiber  die Biologie  der Wasseroli-
 gochaeten und besonders der Tubi-
 ficiden.  Der Gegenstand wird unter
 drei  Gesichtspunkten abgehandelt;
 die Festlegung physikalischer und
 chemischer Ertr^glichkeitsgrenzen
 fur die einzelnen Arten, das  Suchen
 nach Leitor ganismen,deren Vorkom-
 men Oder Abwesenheit zur Beschrei-
 bung des betreffenden Wassers ver-
 wendet werden konnte und schliess-
 lich genaueAnalysen der zusammen-
 vorkommenden Organismen mit be-
 sonderer Betonung der Identifizier-
 ung der  gefundenen Arten.  Unsere
 luckenhaften Kenntnisse des ersten
 Punktes werden erortert, aber wegen
 der Wechselwirkung  der  einzelnen
 Faktoren in der Natur, wegen der
 Veranderlichkeit der Ertraglichkeit-
 sstufen innerhalbder einzelnen Arten
 wahrend der verschiedenen Leben-
 sabschnitte   und  wegen  anderer
 Schwierigkeiten konnen gegew'artig
 kaumwichtigeSchlusse gezogen wer-
 den. ZumzweitenPunktwirdgesagt,
 dass z.Zt. kein allgemein brauch-
 barer Leitorganismus zur Verfugung
 steht,  wenigstens nicht  unter  den
 Tubificiden.    Schliesslich   wird
 die Artenverteilung im  Bezug auf
 bekannte  Ursachen der   Verunre-
 inigung britischer Flu'sse beschrie-
 ben und die Hoffnung ausgesprochen,
 dass ins  Einzelne  gehende Unter-
 suchungen   in dieser Richtungdi-
 eses Bild klaren unddadurchUnter-
 suchungen mit Wirbellosen zu einem
 brauchbaren  diagnostichen Werk-
 zeug machen werden.
ENVIRONMENTAL REQUIREMENTS
OF SHRIMP.  A.C. Broad, p. 86 .
This  paper is largely a review of
an abundant literature that deals with
three species of  penaeid  shrimp,
Penaeus setiferus, Penaeus aztecus,
and  Penaeus duararum,  of direct
commercial  value in the  United
States.   Although studies of these
shrimp embrace a period of about
50 years  and present a wealth of
information on general ecology, life
histories,  distribution,  and syste-
matics,  basic questions of the re-
lationship of shrimp to their environ-
ment  have not been  answered or,
indeed,  dealt with  in a  manner
likely to yield answers. Thus, while
almost every investigator during the
past 30 years has considered salinity
in relation  to  shrimp distribution
(including  the author of this paper),
it is still  not possible to state what
effect salinity may have, for example,
CONDITIONS DE MILIEU POUR LES
CREVETTES. A. C. Broad, p. 86 .
Cette communication est principale-
ment une revue de 1'abondante lit-
terature concernant trois especes
de  crevettes  (bouquets^, de valeur
commerciale  aux Etats  Unis:
Penaeus setiferus, Penaeus axtecus,
et  Penaeus  duorarum.    Quoique
les etudes sur ces crevettes couvrent
une periode de 50 ans et presentent
une richesse d'information sur leur
ecologie genlrale, leur histoire, leur
distribution et  la systematique, les
questions de base sur les relations
entre les crev^tes et leur milieu
n'ont pes eti resolues ou du moins
traitees  d'une maniere susceptible
de  dormer  une reponse.   Ainsi,
tandis que la plupartdeschercheurs
pendant les 30 dernieres annees  (y
compris 1'auteur de ce papier) ont
considere le salinite en liaison avec
la distribution des crevettes, iln'est
UMWELTBEDINGUNGEN     FUR
GARNELEN.  A. C. Broad,  p. 86  .
Der vorliegende Bericht ist grossen-
teils  eine Besprechung der reichen
Literatur iiber drei Arten von pen-
aeiden  Garnelen, Penaeus  seti-
ferus, Penaeus aetecus  und Pena-
eus duorarum,  die in den Vereinig-
ten   Staaten wirtschaftlich wichtig
sind.  Obwohl solche   Studien sich
uber  einen  Zeitraum  von etwa 50
Jahren  erstrecken und  viel  iiber
allgemeine Oekologie, iiber Leben,
Verteilung und  Systematik enthal-
ten,  so bleiben doch grundlegende
Fragen uber  die  Beziehungen der
Garnelen zu ihrer Umwelt unbeant-
wortet oder wurden in einer Weise
angegangen,  dass  Antworten un-
wahrscheinlich sind.   So hat  wah-
rend der verflossenen 30 Jahre fast
jeder Forscher, einschliesslich des
Verfassers  dieses     Berichtes,
den Salzgehalt in seiner Beziehung
                                                       381

-------
on the growth of shrimp.  Indeed,
there is no general agreement on
the growth rates of the three species.
Effects  of temperature on shrimp
are little known and possible effects
of oxygen concentration  are  not
known at all.  Studies involving com-
mon pollutants have not  been at-
tempted.

   Commercially harvested shrimp
spawn at  sea.  Unlike the majority
of  Crustacea  that  provide  some
measure of brood pouch protection,
penaeids shed their eggs, evidently
while  swimming at some   inter-
mediate depth.  The young hatch in
the naupliar stage and pass through
a long and complex larval phase at
sea.  The recently metamorphosed,
postlarval shrimp usually are found
in shallow estuaries of relatively
low salinity and generally high tem-
peratures.  A direct relationship
between  salinity and the size of
juvenile  shrimp  is  demonstrable
during  the  seaward migration of
young.    Some  evidence  indicates
differences  in salinity optima be-
tween the three commercial species,
presumably  effective  during   the
juvenile  phase   that  is adjudged
the most  critical period in the life
history.  Recent trends in the com,-
mercial  fishery  suggest  a  change
in the  species  composition  of  the
penaeid  population  of  the  waters
adjacent to the southeastern  United
States.   The significance of  this is
obscure.

   The  need for basic physiological
research on commercially harvested
shrimp is considered to  be  acute.
pas  encore possible  d'etablir quel
effet peut avoir la salinite sur, par
exemple,  la croissance  des cre-
vettes.  En verite, il n'existe aucun
accord  general sur  la  vitesse de
croissance  de  ces trois especes.
L'influence  de la temperature est
peu connue  et  celle  possible de la
concentration en oxygene dissous ne
1'est pas du tout. Des etudes sur
les substances polluantes communes
n'ont pas ete abordees.

   Les  crevettes recoltees com-
mercialement frayent en mer. Con-
trairement a la majorite des crust-
aces qui assurent quelque protection
a leur poche d'oeufs, les peneides
perdent leurs  oeufs  en nageant a
des  profondeurs moyennes.   Le
jeune a  Peclosion se trouve au stade
nauplius et passe par  une longue
phase larvaire  complexe en mer.
Les  crevettes  post-larvaires, nou-
nouvellement metamorphosees,  se
trouvent  generalement  dans  les
estuaires  peu profonds,  de salinite
relativement faible  et a des tem-
p£ratures elevees.

   Une  relation  directe entre la
salinite et  la teille de la jeune
crevette est perciptible  pendant la
migration des jeunes vers la mer.
Quelques  remarques  indiquent des
differences  dans  1'optimum de sa-
linite entre  les trois  especes com-
merciales,  effectives sans  doute
pendant la  phase juvenile  qui est
jugee la plus  critique  de toute la
vie.  De nouvelles orientations dans
la peche commerciale suggerent un
changement  dans la composition des
especes  de  la population peneide
des eaux adjacentes aux Etats Unis
du Sud  Est.   La signification de
ceci est obscure.

   La  necessite  d'une   recherche
physiologique  de  base  sur  les
crevettes  recoltees  commerciale-
ment apparait urgente.
zum Vorkommen der Garnelen stu-
diert; und dochkannder Einflussdes
Salzgehalts  z. B. auf das Wachstum
der Garnelen auch heute noch nicht
angegeben werden.  Sogar uber die
Wachstumsraten der drei Arten sind
die Meinungen noch nicht einheitlich.
Die Einfliisse  der Temperatur sind
wenig bekannt und uber die mogli-
chen  Wirkungen der  Sauerstoff  -
konzentration weiss  man so  gut wie
nichts.   Studien im  Zusammenhang
mit den gewohnlich  anzutreffenden
Verunreinigungen  sind noch nicht
versucht worden.

   Die  Garnelen des  Handels lai-
chen im Meer,  Im  Gegensatz zur
Mehrheit der Crustaceen, die ihren
Jungen  zu einem gewissen Grade
Schutz in einem Beutel bieten, ver-
breiten   die  Penaeiden  ihre  Eier
anscheinend wahrend sie in  mittle-
rer Tiefe schwimmen.  Nach dem
Nauplienstadium   machen die Jun-
gen eine lange und verwickelte Lar-
venentwicklung  im  Meer  d u r ah.
Kurz  darauf findet man die jungen
Garnelen in seichten Flussmundun-
gen von relativ geringem Salzgehalt
und  im allgemeinen  hohen Tem-
peraturen. Eine unmittelbare Bezie-
hung  zwischen   Salzgehalt   und
Grbsse  der jungen  Garnelen kann
wahrend ihrer Wanderung ins Meer
beobachtet werden.  Anzeichen sind
vorhanden,  dass  Unterschiede  in
den  Salzgehaltbestwerten  fur  die
drei handelsiiblichen Arten bestehen,
die vermutlichwahrend des Jugend-
stadiums, das  allgemein als die
kritische Zeitim Lebendieser Tiere
angesehen wird, wirksam sind. Seit
einiger  Zeit bestehen in der Handels-
fischerei  Hinweise darauf,  dass
eine Anderung  der Artenverteilung
in  den   Penaeidenvorkommen  der
Kiistengewasser  der  siidb'stlichen
Vereinigten  Staaten feststellbar ist.
Die Bedeutung dieser Beobachtung
ist nicht klar.

   Grundlegende     physiologische
Forschungen an Garnelen des Han-
dels werden als dringend nBtig erach-
tet.
ROLE OF  WATERSHED MANAGE-
MENT IN THE MAINTENANCE OF
SUITABLE  ENVIRONMENTS FOR
AQUATIC  LIFE.    W.E.  Bullard.
p. 265. This paper defines "water-
shed,"  "watershed  management,"
and  "suitable  environments  for
aquatic life"; describes the many
causes  of  change in the environ-
ment; and  tells  how the factors in
change  may be controlled or modi-
fied.    Natural  causes  of change
cited  are earth movements, lightn-
ing, fires,  reworking  of  stream
channels  by  major floods,  and
animals.  Development  of a water-
 LE ROLE DE CONDUITS DU LIGNE
 DE  PARTAGE  DES EAUX POUR
 MAINTENIR LES MILIEUX CON-
 VENABLE POUR LA VIE AQUITI-
 QUE.    W.  E.  Bullard.  p. 265  .
 Cette  communication definie«ligne
 de partage  des eaux,^ ^adminis-
 tration de le ligne  de partage des
 eaux3", et «les milieux convenables
      '                      t
 pour  le vie aquatique»  et decrit
 les  causes  multiples  de  change-
 ment  dans  le  milieu,  et expose
 comment les facteurs  en  change-
 ment  peuvent   §tre commandesou
 modifies.  Les  causes  de  change-
 ment naturelcities sontles mouve-
DIE  ROLLE DER  UBERWACHUNG
VON EINZUGSGEBIETEN ZWECKS
AUFRECHTERHALTUNG    EINER
FUR DAS LEBEN IMWASSERGUN-
STIGEN  UMGEBUNG.   William E.
Bullard,  Jr.  p. 265 .  Der Artikel
definiert ^Wasserscheide Oder Ein-
zugsgebiet",    JUinzugsgebietkon-
trolle'* und ^filr das Leben im Was-
ser geeignete Umgebung";dieman-
nigfachen Anderungen in der Umge-
bung werden beschrieben und es wird
angegeben, wie diese Faktor en selbst
wiederum  gehandhabt,   gesteuert
oder geandert werden k'onnen. Natiir-
liche Ursachen von Veranderungen
                                                       382

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shed  causes  change through  soil
disturbance with  consequent  in-
creased  runoff,  erosion, and sedi-
mentation; through loss of shade by
removal of the plant cover; through
direct channel changes;  and through
additions of many kinds of materials
to stream loads.  Contributing fac-
tors subject to control include road
construction, timber  harvest, live-
stock  grazing,  farming,  mining,
miscellaneous construction, recre-
ation, and waste disposal. Examples
of recommended control methods are
given.  To control natural factors,
animal populations can be modified,
excess debris can be cleaned from
channels, fires can be suppressed,
flood  control structures can be in-
stalled, and degraded watershed soil
and cover can be rehabilitated.
 ments de  terre,  feux  d'eclair,  le
 retracage  des canaux  des fleuves
 par deluges majeurs,et lesanimaux.
 Le developpement d'une  ligne de
 pertage des eaux cause  des change-
 ments a travers le derangement des
 sols avec  pour consequence, 1'ero-
 sion,  et la sedimentation; a travers
 la perte d'ombre par la suppression
 des plantes superficielles & travers
 le  changement  des  canaux  et  a
 travers  1'addition  de  beaucoup de
 types de limon.  Le sujet de facteur
 de contribution par le  contr3le in-
 cluent la  construction de routes,
 le boisement,   paturages pour
 animaux  domeatiqes,  fermage,
 minage,   constructions   diverses,
 nouvelles  creations et  vastes  dis-
 positifs.  Des exemples de controle
 recommendes sont donnes.   Pour
 contr6ler les facteurs naturels, les
 populations animales peuvent entre
 mofifie, les exces de debris peuvent
 etre  nettoye des canaux, les  feux
 peuvent §tre supprime, le contrSle
 des structures des cours d'eau peut
 ttre  installe  et  le sol degrade1  et
 couvert peut Stre rehabilite.
sind  Erdbewegungen,  Feuer durch
Blitzschlag,VerlegungyonFlusslau-
fen  nach grosseren  Uberschwem-
mungen und Tiere.  Die Entwicklung
eines  Einzugsgebietes verursacht
Bodenveranderungen und als Folge
vermehrten  Abfluss,  Erosion und
Ablagerung;  Entfernung der Pflan-
zendecke bringt Verlust von Schat-
ten; Flussbettanderungenfmden statt
und  vielartige Stoffe vermehren die
Flussbelastung. Weitere Faktoren,
welche kontrolliert werden kb'nnen,
sind Strassenbau, Holzfallung, Vieh-
weiden,  landwirtsehaftliche   Bod-
dennutzung, Bergbau,  Bauten  ver-
schiedenster Art,  Wassersport und
Abwasserbeseitigung.    Als  Bei-
spiele fur die Kontrolle natiirlicher
Faktoren werden  genannt   Ander-
ung  der  Tierwelt,  Reinigung der
Flusslaufe, Unterdriickung  vonFeu-
ern, Anlegen von I Hochwasserdei-
chen und die Verbesserung von Bod en
und Bodendecke schlechter Einzugs-
gebiete.
 THE PROBLEMS  IN  DETERMI-
 NATION OF THE CAUSE  OF FISH
 KILLS.    G.E.  Burdick.   p. 289 .
 Fish kills usually result from a spill
 or  over-normal discharge of a pol-
 lutant   that,  after dilution, tempo-
 rarily exceeds the tolerance of the
 species  present.   For this reason
 samples for analysis should be col-
 lected as soon as possible after  the
 kill.   Time-concentration  toxicity
 curves  covering  0  to  24 hours  aid
 in evaluation.

   Oxygen deficiency  is  the  most
 frequent and  most easily  demon-
 strated cause  of kill.

   Mortality caused by toxic  com-
 pounds from industrial operations is
 more difficult to prove.  Basic  in-
 formation  enabling chemical deter-
 mination of compounds and decom-
 position  products  and  of  their
 possible effect  and interaction i is
 necessary.

   Agricultural  and  pesticide
 chemicals,  while  usually  not  as
 difficult  to evaluate, present major
 problems in chemical identification
 and  quantitative  determination due
 to extremely high toxicity.  Present
 methods are  not adequate to de-
 termine  certain  chemicals in fish
 tissue.

   Interactions may require labora-
 tory determinations on a specific
water, under controlled oxygen con-
tent, pH, temperature, and concen-
PROBLEMES POUR DETERMINER
LES CAUSES DE MORTALITE'DES
POISSONS.   G.E.  Burdick.  p. 289.
Les mortalites de poissons sont dues
en  general  a un rejet au  a" un
deversement anormal de substances
polluantes  qui, apres  dilution, de-
passent momentanement la tolerance
des especes presentes.  Pour cette
raison, les echantillons pour analy-
ses devraient Sire prlleves aussitot
que  possible apres  la mortalite.
Les courbes do toxicitl, temps en
function de la concentration, pendant
24 h., aident J 1'estimation.

   Un manque d'oxyglne est la cause
de  mortalit6 la  plus  frequente et
la plus facile a prouver.
   Une mortalite provoquee par des
composes toxiques provenant d'op-
erations industrielles est plus dif-
ficile a demontrer. Uestnecessaire
de  posseder des  informations de
base  permettant  la determination
chimique des composes et des pro-
duts de decomposition,  leurs effets
possibles et  leurs inter-actions.

   Les produits chimiques agricoles
et pesticides, generalement moins
difficile  a  evaluer, prlsentent de
grands  problemes d'identification
chimique et  de dosage quantitatif
en raison de leur tres grande toxicite,
Les  methodes actuelles ne permet-
tent  pas de doser  certains produits
chimiques  dans   les  tissus  des
poissons.
DIE PROBLEMS IN  DER FEST-
STELLUNG DER URSACHEN VON
FISCHSTERBEN.  George E.  Bur-
dick.   p. 289.   Fischsterben_ sind
geivohnlich die Folgen eines Uber-
falls   oder   einer  ubernormalen
Einleitung   einer Verunreinigung,
welche  nach Verdiinnung  zeitweise
die Toleranz der vorhandenen Arten
uberschreitet.  Deshalb miissen
Analysenproben so bald als moglich
nach  dem Sterben gesammelt wer-
den,, Giftigkeitsschaubilder, inwel-
chen die  Kbnzentration  gegen die
Zeit von 0 bis 24 Stunden aufgetragen
1st, helfen in der Beurteilung.

   Sauerstoffmangel  1st die haufig-
ste und am leichtesten feststellbare
Ursache eines Fischsterbens. Sterb-
lichkeit  infolge von Giftstoffen aus
industrieller Tatigkeit ist  schwie-
riger nachweisbar.  Die chemische
Bestimmung von Verbindungen und
Zersetzungsprodukten, sowie ihrer
Wirkung und Wechselwirkungerfor-
dern grundlegende  Kenntnisse der
mbglicherwise    in  Betracht kom-
menden Industrie.
   Landwirtsehaftliche Chemikalien
und   Ungeziefervertilgungsmittel
sind ein  grosseres Problem in der
chemischen  Identifizierung   und
anantitativen Bestimmung,  obwohl
_\e gewohnlich unschwer bestimmt
werden konnen.   Unsere heutigen
Methoden sind  fur die Bestimmung
gewisser   Chemikalien  im Fisch-
gewebe unzureichend.
                                                       383

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trations  of  possible synergists  or
antagonists  corresponding to those
present at the time of kill.  Con-
firmation by experimentally altered
solution  may  also be  necessary.

   The greatest needs are for more
exact and sensitive chemical pro-
cedures,  a   system of  screening
chemical compounds, improved in-
formation of synergism and antago-
nism procedures for utilizing post
mortem analysis, and mathematical
models permitting evaluation  and
correction for simultaneous  inter-
action between components  of the
toxic system.
   Les  inter-actions  peuvent  de-
mander des  essais  de laboratoire
realises avec une  eau specifique,
une concentration d'oxyge'ne, un pH
et une temperature contrSlle et des
concentrations en elements antago-
nistes  au  synergiques  possibles,
correspondant a celles prlsentees
au moment de la mortalite.

   Une confirmation par une solution
poullee  experimentalement  peut
aussi §tre ne"cessaire.

   II  serait tres necessaire d'avoir
des methodes chimiques plus exactes
et plus sensibles,  un  systeme de
triage des composes chimiques,  de
meilleures  informations sur  les
processus desynergismeetd'antag-
onisme ofin de les  utiliser dans
les analyses post mortem, et des
tables  mathematiques  permettant
devaluation et la correction pour
des inter-actions simultanees entre
les  composants  d'un  systeme
toxique.
   Wechselwirkungen  kbnnen Labo-
ratoriumsbestimmungen  an einem
bestimmtenWasser unter kontrol-
lierten Bedingungen beziiglich Sau-
erstoffmenge,  pH, Temperatur und
Konzentrationen   moglicherweise
vorhandener synergistisch Oder an-
tagonistisch wirkender  Substanzen
erfordern,  welche den zur Zeit des
Fischsterbens vorhandenen entspre-
chen.  Bestatigung durch geanderte
Versuchslosungen kann ebenfalls
notig sein.

   Am notigsten sind genauere und
empfindlichere chemische Verfah-
ren, ein System zum Aussondern
chemischer   Stoffe,    bes-
sere Kenntnisse iiber Synergismus
und  Antagonismus zur  Anwendung
in post mortem Auswertungen  und
mathematische Modelle, welche die
Bestimmung und  Verbesserung fur
gleichzeitige Wechselwirkungen der
Bestandteile  des giftigen Systems
ermfiglichen.
REACTION OF ESTUARINE MOL-
LUSKS TO SOME ENVIRONMENTAL
FACTORS. Philip A. Butler, p. 92 .
This  history  of  oyster  culture
demonstrates   that   within  broad
limits these  mollusks survive and
even prosper over a wide range of
environmental conditions.  Experi-
ence  also  demonstrates that ap-
parently subtle, or  at  least for the
most  part unidentified,  environ-
mental factors may drastically alter
the character and quality of oysters.
A study to  delineate  some of the
causal factors  has  been conducted
for more than a decade on a natural
population of oysters in Santa  Rosa
Sound, an estuarine environment in
northwest Florida.  The population,
too small to be fished commercially,
is a complex of three native species
of  the  genera Ostrea and Cras-
sostrea.

   Continuous  records  have  been
maintained on seasonal and annual
changes  in  salinity,  temperature,
rainfall, and  the set of oysters on
experimental cultch.   Comparative
data have been collected  and are
summarized  showing the relation-
ships of water pumping rates,  shell
movement,  and  growth to  such
features as  water  currents,  food
(chlorophyll), and carbohydrate-like
substances normally present in the
environment.

   The sensitivity of shell deposition
as a criterion  of well-being of the
oyster is described,  and data are
presented summarizing the response
of  various  mollusks  to artificial
pollutants, such  as   agricultural
pesticides,  under  laboratory  con-
REACTION  DE  MOLLUSQUES
D'ESTURINE  A DES  FACTEURS
DU MILIEU AMBIANT.  Philip  A.
Butler,   p. 92 .   Ce rapport  de
culture d'huitres, demontre que dons
de vastes  limites, ces collusques
survivent et mSme prosperent dans
un large domaine de  condition  de
milieu ambient.   L'experience de-
montre   aussi   qu-apparamment
subtil, ou au moins pour la plupart
non identifie, les facteursdu milieux
ambiant peuvent alterer rigoureuse-
ment  le caractere et la qualite des
huitres.  Une  etude pour delimiter
quelques un des f acteur s accidentels,
a etc faite pour plus d'une  decade
sur  une  population  naturelle
d'huitres dans Santa Rosa  Sound,
un milieu  estuairin dans le Nord
Quest de la Floride. La population
trop petite  pour etre peche com-
mercialement  est  un  complexe  de
trois  espe'ces des genera  Ostrea
et Crossastrea.

   Les  mentions  continuelles  ont
etc releve"  sur  les   changements
saisoniers  et  annuels en salinite,
temperature, chute de pluie et sur
le jeu d'huitre de ^culture experi-
mentale. Les donnees comparatives
ont ete  collecte  et sont resumees,
montrant les relations  entre le taux
d'eau pomp£,  le  mouvement des
coquilles, la croissance   de telles
characteristiques et les courants de
1'eau, la nourriture(chllorophyle),
la substance  comme  hydrate  de
carbone normalement pr6sente dans
le milieu.

   La sensitivite de deposition  de
coquille  comme  crite're  de bien-
§tre de 1'huitre  est  decrit et les
DIE REACTION VON MOLLUSKEN
AN  FLUSSMUNDUNGEN GEGEN-
UBER EINIGEN UMGEBUNGSFAK-
TOREN. Phillip A. Butler,  p. 92 .
Die  Geschichte der Austernkultur
zeigt, dass  diese Mollusken inner-
halb welter Grenzen zu  leben ver-
mbgen  und  dass sie trotz grosser
Unterschiede  in den  Umgebungs-
bedingungen  wohl  gedeihen.   Die
Erf ahrung lehrt auch, dass anschein-
end  geringfiigige Oder wenigstens
grosstenteils   nicht  identifizierte
Umgebungsbedingungen den Charak-
ter und die Gute der Austern dras-
tisch andern konnen. Ineiner Studie,
die  sich uber mehr als 10 Jahre
erstreckte und an einer naturlichen
Austernansiedlung  im Santa  Rosa
Sund, einer Flussmiindung in Nord-
westflorida,  durchgefuhrt  wurde,
wird versucht, diese zufalligen Fak-
toren zu  schildern.   Die Ansied-
lung war zu klein,  um geschaftlich
ausgebeutet zu werden; sie umfasste
eine Gruppe von drei einheimischen
Arten  der  Gattungen Ostrea und
Crassostrea.

   Jahreszeitliche und jahrliche An-
derungendes Salzgehaltes, der Tem-
peratur, des   Regenfalls und des
Ansetz ens der Austern an Versuchs-
material   wurden  dauernd aufge-
zeichnet. Vergleichbare Werte wur-
den  gesammelt und in einer Uber-
sicht zusammengefasst; diese  zeigt
die Beziehungen zwischen Wasser-
forderleistung, Schalenbewegung und
Wachstum  auf  der  einen Seite zu
solchen Faktoren wie Wasserstro-
mung, Nahrung (Chlorophyll) und den
gewohnlich in dieser Umgebung vor-
h.andenen   kohlenhydratahnlichen
Stoffen auf der anderen.
                                                      384

-------
 ditions.   The data  indicate the dif-
 ferential reaction of oysters to these
 pollutants  and stress the  need for
 continuing research  to  select ef-
 fective agricultural and marine pest
 control chemicals that are relatively
 nontoxic   to desirable  estuarine
 forms.
donnees  sont prlsentees  resumant
dans des  conditions la  reaction de
laboratories  de  mollusque varils
aux  polluants  artificiels  tel  que
pesticides agricoles.   La donn6e
indique les differents reactions des
huitres a ces polluants et donne le
mayen de continuer la recherche
pour un controlede pesticide marins
et agricoles qui sont relativement
non toxiques.
   Die Empfindlichkeit der Schalen-
ablagerung  als  des Anzeigers der
Gesundheit  der  Austern  wird be-
schrieben und Versuchsergebnisse
werden gebracht, welche die Reak-
tion verschiedener  Mollusken auf
kunstliche  Verunreinigungen,  wie
landwirtschaftliche   Schadlingsver-
tilgungsmittel, unter Laboratoriums-
bedingungen zusammenfassen.  Die
Ergbnisse  zeigen  die verschieden-
artigen Reaktionen der Austern die-
sen Verunreinigungen gegenuber und
betonen die Notwendigkeit fur mehr
Forschungsarbeit,  damit wirksame
chemische Stoffe zur Schadlingsbe-
kSmpfung   in   Landwirtschaft und
Fischerei gewahlt  werden konnen,
welche ftir wiinschenswerte lebende
Formen  an Flussmiindungen ver-
haitnismassig ungiftig sind.
 THE ENVIRONMENTAL REQUIRE-
 MENTS OF FRESH WATER PROTO-
 ZOA.   John Cairns,  Jr.   p. 48  .
 Although free-living Protozoa have
 a  cosmopolitan distribution, a par-
 ticular species will occur only where
 the appropriate environmental con-
 ditions  exist.   Since  the environ-
 ment changes constantly, a constant
 replacement  of  the  component
 species of a protozoan population is
 a  normal event.  An examination of
 protozoan  populations from  202
 areas, classified as healthy or semi-
 healthy according to the system of
 Patrick (1949), in rivers and streams
 of the United States and other parts
 of the world resulted in identification
 of nearly 1200 species.  Approxi-
 mately  75 percent  of these  species
 occurred in three or fewer areas,
 or  less than 1.6  percent, of the
 areas sampled.   Of the 25 percent
 that  occurred four of more times,
 only   20   species were found in
 25 percent of the areas studied. For
 those species with saprobian desig-
 nation,  some  sampling areas  had
 excellent agreement in composition,
 although the  greater  number did
 not.  An association matrix was made
 for the 20 most common species.
 A  Chi  square test of significance
 was  run on  the  190 possible as-
 sociations of species pairs, and of
 these,  44 pairs occurred together
 more frequently than would be ex-
pected  from  chance alone at the 5
percent level of confidence.   The
 data indicated that associations of
three or more species also existed.
 Three  main facts were noted in the
 course  of  the analysis:  (1) pairs
or  larger  groups of  associated
 species always had virtually identi-
 cal ranges of environmental  con-
ditions;  (2) these  species  always
tolerated  rather broad ranges of
environmental conditions;  and  (3)
having identical ranges of tolerance
LES BESOINS DE MILLIEU POUR
LES  PR.OTOZOAIRES D'EAU
DOUCE.  John Cairns,  Jr. p. 48 .
Bien  que les protozoaires a 1'etat
libre  aient une distribution cosmo-
polite, des especes particulie'res se
presenteront seulement ou les con-
ditions  convenables  de  milieu
existent.  Puisque le milieu change
constamment, unremplacement
continuel  des  especes  constituant
une population  de protozoaires, est
un evenement  normal.  Un examen
des populations de protozoaires de
202 zones, classics comme saines
out semi-saines d'apres le systlme
de Partick (1949), dans les fleuves,
les rivieres des  Etats-Unis et les
autres parties du monde, donne une
identification  de  pres    de  1200
especes.   Approximativement  75%
de ces especes se presentaientdans
trois  zones et me*me moins,  soit
moins de 1.6% des zones echantil-
lonnees.  Des 25% qui se presentait
quatre fois ou plus, seulement vingt
especes  furent trouvees  dans  25%
des zones etudiles.   Pour ces
especes avec les  designations
saprobian  certaines des  zones
d'echantillons   avaient  d'excellent
rapport en composition, malgre que
le plus grand nombre n'y soit pos.
Une matrice d'association fut faite
pour  les vingt especes, les plus
communes.  Une  chi carre epreuve
de  signification  fut faite sur les
190  associations  de  paires  des
especes  possibles, et 44 des 190
paires  se presenterent  ensemble
plus frequemment que ne le donnait
le  facteur de  chance,  ce facteur
de  chance auralt etc donne  a 5%.
Les  donnee's  ont indiqul que les
associations  de  trois especes ou
plus  ont  exist! e'galement.   Trois
faits  principaux marquaient dans le
cours de  1'analyse.  (1) Les paires
des plus grands groupes des especes
ont toujours eu des domaines pr esque
 DIE ERFORDERNISSE VON FRISCH-
 WASSERPROTOZOEN  HINSICHT-
 LICH  IHRER  UMGEBUNG.   John
 Cairns,  Jr.  p. 48  . Obwohl freile-
 bende  Protozoen liber  die ganze
 Welt verbreitet sind, so  werden
 doch die einzelnen Arten nur  dort
 auftreten, wo geeignete Umgebungs-
 bedingungen  bestehen.  Da sich die
 Umgebung dauernd andert, so 1st der
 standige Ersatz  einer  bestimmten
 Protozoenart in einer Ansiedlung ein
 normales Ereignis.  Eine Prufung
 von Protozoenrorkommen  an 202
 Fundstellen in Flussen und Stromen
 der Vereinigten Staaten und anderer
 Lander  fiihrten zur Wentifizierung
 von nahezu 1 200 Arten. Die Fund-
 stellen konnten  nach  dem  System
 von Patrick (1949)  als  ,;gesund"
 Oder Khalb  - gesund" bezeichnet
 werden.   Ungefahr  75% der  ver-
 schiedenen  Arten traten in 3 Oder
 weniger  Fundorten, also in weniger
 als  1,6% der Beobachtungsstellen,
 auf.  Von den  25%, welche viermal
 Oder ofters vorkamen, wurden nur
 20  Arten in 25% der  untersuchten
 Gebiete  gefunden.    Fur  die  als
 Faulnisbewohner bezeichneten Arten
 zeigten  einige Beobachtungsstellen
 sehr gute Ubereinstimmung in der
 Zusammensetzung; fur die Mehrheit
 traf das jedoch nicht zu. Eine Asso-
 ziationsmatrix wurde fur die 20 am
 haufigsten auftretenden Arten  ge-
 macht. Eine X2 Probe wurde fur die
 190  moglichen  Assoziationen  von
 Artenpaaren  gemacht undvondiesen
 kamen 44 Paare zusammenhaufiger
 vor  als durch  Zufall allein auf der
 5%   Stufe der  Zuverlassigkeit zu
 erwarten gewesen ware. Die Werte
 zeigten, dass Assoziationen von drei
 Oder mehr Arten ebenfalls  vorka-
 men. In  der Hauptsache wurden drei
 Tatsachen im  Laufe der  Analyse
 beobachtetr(l) Paare Oder grossere
 Gruppen  von zusammen auftretenden
 Arten  batten stets  praktisch die
                                                       385

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to the chemical and physical environ-
ment does not insure that species
will be  associated more often than
would happen by chance alone.

   Due to the relatively low number
of associated species and the broad
range of tolerance of these species
to the chemical and physical environ-
ment, it is  evident  that the best
citer ion for evaluation of the degree
to which the requirements of Proto-
zoan populations are being met is
the diversity of species within these
populations.   Since  Protozoa are
part of a larger aquatic community,
the  entire aquatic  flora  and fauna
should  first be evaluated and the
structure and diversity of the proto-
zoan population analyzed both as a
unit and in terms  of its relation-
ship to  the structure  of the larger
community  of  which  it  is a part.
identiques aux conditions de milieu;
(2)  Ces especes ont toujours tolere
les  domaines plutot  vaste des con-
ditions  de  milieu; et (3) avoir les
domaines de tolerance identique au
milieu  chimique  et  physique,
n'assure pas que les especes seront
associees plus souvent qu'elles ne
le  seraient par  hasard.   Vue le
nombre  relativement  bas  des
espe"ces  associees  et  le  large
domaine de tolerance de ces especes,
au  milieux  chimique  et physique
it  est  evident  que  les meilleurs
criteres pour 1'evaluation du degre
dans  lequel les besoins de proto-
zoaires sont requis,  est ladiversite
des especes a  1'interieur mSme de
ces populations.  Pisque les proto-
zoaires  occupent la  plus grande
partie de la communaute aquatique,
la  faume et la flore aquatique
seraient permierement evaluees, la
structure et la diversite des popu-
lations protozoaires analysees en
bloc  et en ces termes, de sa re-
lation avec la structure de la plus
grande communaute' a laquelle  il
appartient.
gleichen Bereiche der Umgebungs-
bedingungen,(2)  diese  Arten ver-
trugenimmerziemlichweite Berei-
che  deiser  Bedingungen  und   (3)
Arten, welche die gleichen Bereiche
der Toleranz gegeniiber chemischen
undphysikalischen Umgebungsbedin-
gungen haben,, kommen nicht not-
wendigerweise b'fter assoziiert vor
als das durch Zufall allein der Fall
ware.

   Infolge der relativ geringen Zahl
der assoziierten Arten und  wegen
der breiten Bereiche der Toleranz
fur die chemische undphysikalische
Umgebung  ist  es  klar,  dass  die
beste Kennziffer zur Au.swertung des
Grades, bis zu welchem die Ansprii-
che  von Protozoenvorkommen be-
friedigt werden, die Verschiedenheit
dieser Arten innerhalb dieser Vor-
kommen ist.   Da die Protozoen
ein  Teil einer grosseren  Gemein-
schaft sind,  so  sollte die  gesamte
Wasserfloraund Fauna zuerstunter-
sucht werden.  Dann sollte der Auf -
bau  und  die Verschiedenheit der
Protozoenvorkommen  sowohl  als
Einheit wie auch hinsichtlich ihrer
Beziehungen zum Aufbauder grosse-
ren Gemeinschaft,  dessen  Teil  sie
sind, analysiert werden.
PESTICIDE-WILDLIFE   RELA-
TIONS.   Oliver  B.  Cope.   p. 245.
This  subject covers the length and
breadth of most  approaches to the
pesticide  problem as  it relates  to
wildlife. Detection and/or measure-
ment of organic pesticides in wild-
life and the environment are needed
to  achieve an understanding of the
patterns of toxicity.  The methods to
be  used for detection and measure-
ment depend upon the objective of the
study, the availability  of assay
methods,  and the capability of the
laboratory.   Toxicity to  aquatic
life can be understood  and predicted
only with a knowledge  of the effects
of  a  toxicant on the  environment,
including   food;   the  influences  of
factors in the environment on tox-
icity; the relative roles of chronic
and acute toxicity; and a  compre-
hensive characterization of the in-
dividual  animals under consider-
ation.
LES RELATIONS PESTICIDES SUR
LA VIE SAUVAGE. Oliver B. Cope.
p. 245,  Ce sujet couvre la totalite
de la plupart des acces auprobleme
des pesticides en vie. Ladecouverte
et, ou  la  mesure des  organiques
pesticides  en  vie,   et  le  milieu,
sont  employes  pour  la complete
comprehension  des  exemples  de
toxique.   Les  methodes a  utiliser
pour  la decouverte  et  la  mesure
dependent  de  1'objectif  de  1'etude,
de  la disponsibilite  des methodes
d'epreuve,  et  de  la capacite du
laboratoire.   La  toxiquite  four la
vie aquatique peut etre comprise et
predite seulement avec la connais-
sance des effects d'un toxique, com-
prenant: la nourriture,  1'influence
des  facteurs dans le milieu de la
toxiquite, les roles relatifs de toxi-
quitS  chronique  et  aigue,  et  une
caracterisation  comprehensive de
1'animal individuel en consideration.
DIE BEZIEHUNGEN ZWISCHEN IN-
SEKTENVERTILGUNGSMITTE LN
UND  NATURSCHUTZ.   Oliver B.
Cope.  p. 245.  Der Gegenstandum-
fasst  in den verschiedensten Rich-
tungen die meisten Wege zur Frage
der Ungeziefervertilgungsmittel in
ihrer   Beziehung zum  Naturschutz.
Entdeckung und Messung von orga-
nischen  Ungeziefervertilgungsmit-
teln in Organismen in ihrer natur-
lichen Umgebung  sind  zum  Ver-
st'andnis der Giftigkeitsbilder notig.
Die  zu diesem  Zweck   beniitzten
Verfahren  hangen vom Zielder Un-
tersuchung, von der Zuverl'assigkeit
der Prufungsmethoden und  von der
Fahigkeit   des  Laboratoriums  ab.
Giftigkeit gegeniiber im Wasser  le-
benden Organismen kann nur dann
verstanden und vorausgesagt werden,
wenn  die  Wirkungen  eines   Gift-
stoffes auf  Umgebung und Nahrung,
der Einfluss gewisser Umweltfak-
toren  auf die Giftigkeit, die relative
Rolle  chronischer und akuter Giftig-
kiet  und   eine  umfassende   Be-
schreibung der Einzeltiere bekannt
sind.
                                                       386

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THE EFFECT OF ENVIRONMENT-
AL FACTORS ONCRABDEVELOP-
MENT.  John D. Costlow, Jr. p. 77 .
Development of the Brachyura gen-
erally follows a similar pattern: a
series of  stages of free-swimming
larvae,  which through successive
molts  attain  an  intermediate  or
transitional  form, which  in turn
metamorphose to  the  pre-adult.
Techniques  have recently been de-
veloped for rearing  crab larvae
under  controlled  laboratory  con-
ditions, from hatching to the first
crab stage and beyond.  The avail-
ability of  large numbers of larvae
of known  stage of  development and
age enabled us to  investigate many
phases of larval development which
previously had been impossible or
impractical  with  larvae  obtained
from the plankton.

   Experiments thus far have been
primarily concerned with the effects
of three or four environmental
factors on larval development.
These  have included studies on the
individual  and combined effects of
salinity, temperature, light, and diet
and how these factors affect length
of individual larval stages,  the total
time required for development to the
crab, the  number  of larval stages,
and survival at individual stages as
well as the over-all  survival.  Of
the 20 species that have been suc-
cessfully   reared to date four or
five are  cited as examples of how
environmental  factors  can  affect
larval development.

   Salinity  tolerance  varies  con-
siderably  from species to species
as  well   as with different larval
stages of  the  same  species.  All
larval stages  of  Rithropanopeus
harrisii  complete  their  develop-
ment at low salinities (5 to 15 ppt)
but have  poor survival at higher
salinities.    Larvae  of  the  drift-
line crab,  Sesarma cineveum,  do
not develop in salinities lower than
20 ppt,  and the larvae of the  com-
mercial  blue  crab,   Callinectes
sapidus,  survive best in salinities
of from 30  to  33 ppt.  Although the
first three zoeal stages  of S.
cinereum   survive  at  31.1 ppt, the
fourth  stage  zoeae rarely meta-
morphose  to  the megalops at this
salinity.   The highest percent sur-
vival  of  larvae of the  mud-crab,
Panopeus  herbstii, however, was at
this same salinity, 31.1 ppt.  Tem-
perature,  in addition to affecting the
speed  of  development,  may  alter
the normal  salinity tolerance of the
individual larval stages.

   Although  photoperiod  does not
appear to affect the development of
Sesarma reticulatum  larvae, con-
INFLUENCE DU MILIEU  SUR LE
DEVELOPPEMENT  DU   CRUBE.
John D.  Costlow, Jr.  p. 77  .   La
developpement  des  Brachyur  suit
generalement  un ordre identique:
une serie de stades larvaires a nage
librex,  qui, per mues successives
attaignent une forme intermediaire
ou transitoire laquelle, a1 son tour,
se  metamorphose  en  pre-adulte.
Des techniques ont recemment ete
de'veloppe'es pour elever des larves
de crabes  en laboratoire dans des
conditions  determinees depuis
1'eclosion  jusqu'au  premier stade
crabe et au d6la.   La disponibilite
d'un grand nombre de larves d'age
et de stade de developpement connus
nous  a  permis  d'etudier de nom-
breuses  phases de  developpement
larvaire ce qui etait impossible
auparavant avec des larves recueil-
lies dans le plancton.

   Jusqu'a  present  les experiences
ont etl  orientees sur 1'influence de
3  ou  4  facteurs du milieu sur le
developpement larvaire. Nousavons
etudie  notamment  1'influence  in-
dividuelle et combineede la salinite,
de la temperature, de la lumiere
et du regime alimentaire et comment
ces facteurs influencent la  duree
de ehaque  stade larvaire,  la duree
necessaire au developpement com-
plet du  crabe, le nombre de stades
larvaires et la survie auxdifferents
stades aussi bien que la survie totale.
Sur  les 20 especes  qui ont  pu
etre elevees avec  succes jusqu'a
ce jour, 4 au 5 sont  citees pour
montrer a  titre d'exemple  combien
les facteurs du  milieu  environnant
peuvent  affecter  le developpement
larvaire.

   La tolerance a la salinite varie
beaucoup d'une espece  a ^1'autre,
aussi bien  que  d'un stade a 1'autre
pour une mime espece.  Tous les
stades larvaires de Rithropanopeus
harrisii  achevent  leur  developpe-
ment  pour  de  faibles salinites (5
a  15 %„) mais n'ont qu'une  faible
survie a de plus  fortes salinites.
Les  larves de Sesarma cinereum
ne se developpent pas a des  salin-
ites  inferieures  a1  20  %0 et  les
larves de  crabe bleu,  Callinectes
sapidus   survivent  mieux dans  des
salinities de 30  a  33 %o.  Quoique
les trois premiers stades zoe de
S.  cinereum. survivent  a 31,1 ppt.
le 4e stade  zoe  se  metamorphose
rarement en megalope a cette  sa-
linite. Cependant le plus grand pour-
centage de  survie du crabe Panopeus
herbstii  se trouve  a  cette  meme
salinite de 31,1 %„, La temperature,
en plus  de son influence  sur la
Vitesse   de  developpement,  peut
alterer  la  tolerance normale a la
salinite   des differents  stades
larvaires.
DER EINFLUSS VON UMGEBUNGS-
FAKTOREN  AUF DIE ENTIWICK-
LUNG VON  KRABBEN.   John D.
Costlow,  Jr.  p. 77 .   Die Ent-
wicklung der Brachyura folgt im all-
gemeinen den gleichen Linien: eine
Reihe von freischwimmenden Lar-
venstufen, dann  eine Ubergangs -
Oder Zwischenstufe,welche schliess-
lich in die Jungendform ubergeht.
Seit kurzem sind  Aufzuchtverfahren
von  Krabbenlarven bis  zur ersten
Krabbenstufe  und  daruber hinaus
unter Laboratoriumsbedingungen be-
kannt.  Wir hatten eine grosse An-
zahl von Larven bekannter Entwick-
lungs - und Altersstufen und konn-
ten deshalb viele  Phasen der Lar-
venentwicklung studieren,was frilher
mit Larven aus Plankton unmoglich
Oder unpraktisch war.

   Bisher  beschaftigten  sich die
Versuche  hauptsachlich  mit  den
Wirkungen von drei Oder vier Umge-
bungsfaktoren  auf  die  Larvenent-
wicklung  entweder allein oder in
ihrem Zusammenwirken,  namlich
Salzgehalt,  Temperatur, Licht und
Nahrung.  Der Einfluss dieser Fak-
toren auf Lange  der  Larven,   Ge-
samtzeit nbtig bis  zur Entwicklung
zur Krabbe, Zahl der Larvenstufen
und Uberleben sowohl der einzelnen
Entwicklungsstufen wie  der ganzen
Entwicklungsreihe wurden studiert.
Bisher wurden 20 Arten erfolgreich
aufgezogen;  davon werden 4 oder 5
als Beispiele fur den Zusammenhang
zwischen  Umgebungsfaktoren  und
Larvenentwicklung aufgefuhrt.

   Die Ertraglichkeit fur Verschie-
denheiten im Salzgehalt  1st von Art
zu Art und fur die glei Che Art inner-
halb  der  Larvenstufen  sehr  ver-
schieden.   Alle  Larvenstufen von
Rithropanopeus harrisii  entwickeln
sich bei  niedrigen Salzgehalten  (5
bis  15 %(,), Uberleben aber  hohere
Salzkonzentrationen nur  schlecht.
Larven von Sesarma cincereum ent-
wickeln  sich unter 20%0 Salzgehalt
uberhaupt  nicht,   die  der blauen
Krabbe,  Callinectes sapidus, uber-
leben Konzentrationen von 30 bis
33%ti am besten.  Obwohl die ersten
drei  Zoeenstufen von S. cinereum
31,1%?, aushalten,  metamorphosiert
die 4.  Stufe bei diesem Salzgehalt
nur selten .  Larven von Panopeus
herbstii indessen iiberlebten gerade
diesen  Salzgehalt  von   31,l%o am
besten.     Die    Temperaturver-
schienheiten beeinflussen die  Ent-
wicklungsgeschwindigkeiten, ko'nnen
aber auch die normale Salztoleranz
der einzelnen Larvenstufen andern.

   Obwohl die Lichtperiode auf die
Entwicklung von Larven von Sesarma
reticulatum ohne  Einfluss zu sein
scheint, so sind doch mehr Versuchs-
                                                       387

-------
siderably  more data are needed to
evaluate  all  aspects  of  the  effect
of light.

   Diet, both natural and synthetic,
varies considerably  in affecting
larval development.  Phytoplankton
retard the time of development of
some species, while in other species
they do not affect development.

   When  the effects of the natural
environmental factors on larval de-
velopment  are better understood, it
will be possible to consider crust-
acean larvae as bioassay animals for
a  wide variety of  studies.    The
regular  sequence of  stages,  the
inter molt periods of known duration,
and the extreme  sensitivity of larval
stages to  toxic  substances should
provide an excellent "indicator" for
the study  of water quality and pol-
lution.
   Quoique  la  photoperiode  ne
semble pas influencer le developpe-
ment des  larves de  Se sarma
reticulatum, des resultats beau coup
plus nombreux sont   necessaires
pour  apprlcier  tous  les  aspects
de 1'activite de  la lumiere.

   Le regime alimentaire, a la fois
naturel  et synthetique, influence le
developpement  larvaire  de  facon
tres  variable.    Le phytoplancton
retarde le developpement de quelques
especes et est  sans influence pour
d'autres.

   Lorsque  1'action des divers
facteurs du  milieu  naturel sur le
developpement  des  larves  sera
mieux comprise, il sera possible
d'envisager les larves de crustaces
comme  animoux  tests  poud   de
nombreuses etudes.  La succession
naturelle  des differents  stades, la
duree separant les mues etant connue
et la grande sensibilite des stades
larvaires  aux substances toxiques,
fourniraient un excellent indicateur
pour 1'etude  de la qualite" des eaux
et des pollutions.
sdaten nbtig,  ehe alle  Seiten  der
Lichtwirkung  ausgewertet werden
konnen.

   Natilrliche und synthetische Nah-
rung wirkt auf die  Larvenentwick-
lung sehr verschiedenartig ein. Phy-
toplankton  verzogert die Entwick-
lungszeit bei einigen Arten, istaber
bei anderen Arten ohne  Wirkung.

   Wenn der Einf luss der natur lichen
Umgebung  auf die  Larvenentwick-
lung besser bekannt ist, dann wird
es moglich sein, Crustaceenlarven
fur  viele  biologische  Studien  zu
verwenden. Die regelmassige Auf-
einanderfolge  der  Entwicklungss-
tufen, ihre bekannte Zeitdauer  und
die ausserordentlich grosse  Emp-
findlichkeit der  Larven gegen Gifte
konnten einen ausgezeichneten  An-
zeiger fur  Wassergute und Verun-
reinigung liefern.
A SURVEY OF ENVIRONMENTAL
REQUIREMENTS  FOR THE MIDGE
(DIPTERA: TENDIPEDBDAE).
La Verne L. Curry, p.  127. A brief
history of  the taxonomy and  the
limnological  importance of the
family is given. When possible, sy-
nonymy is given  for the important
species to enable the  researcher
to relate his data  to that of different
geographical regions.    Interpre-
tations  of  environmental require-
ments for the more common species
of the family are based primarily
on the Michigan fauna.  Evaluations
are  made  for the Holarctic, Neo-
tropical, and Ethiopian realms, how-
ever, when these data are available.
The  environmental conditions con-
sidered are oxygen, carbon dioxide,
sulfides, sulfites, acids,  some
organics,  pH,  temperature, fiber
deposits, and siltation.  These are
considered with  respect  to midge
populations  in lotic  and lentic  en-
vironments, as well as in the littoral
and profundal regions of freshwater
lakes. The maximum conditions
tolerable  to  midge  populations in
these environments are given when
known.  Several general conclusions
are  drawn from  the study.   Field
work indicates that no  group of
midges can be regarded of pol-
lutional indicator  organisms per se.
The  species  Tendipes (T.) riparius
(Meigen)  (=Chironomus  riparius
Meigen) and T. (T.) tentans (Fabri-
cius) (=Chironomus tentans  Fabri-
cius) could be considered as such,
however.  Some species in the family
UN RELEVE DES CONDITIONS DE
MILIEU  REQUISES POUR LES
CHIRONOMIDES (DIPTERA:
TENDIPEDIDAE).      LaVerne  L.
Curry,   p. 127.   On donne ice  un
bref resumfe de la toxonomie et de
Pimportance limnologique de cette
famille. Autant que possible on donne
une  liste de  synonymes  pour  les
especes  importantes afin d'aider le
chercheur  a rapporter ses donnees
a celles  des regions geographiques
diff er entes.  Les interpretations des
conditions  de milieu requises pour
les especes les plus  communes de
cette famille sont basees principale-
ment sur la faune du Michigan.
Cependant  on fait  des evaluations
pour  les  domaines  holoarctiques
neotropical, et ethiopienlorsqueces
donnees sont accessibles.  Les con-
ditions de  milieu consid4rees sont
1'oxygene,  1'anhydride carbonique,
les  sulfites,  les  acides  (les uns
organiques), le pH, la temperature,
les dep8ts fibreux, et 1'envasement.
Ces  conditions  sont  etudiees  en
rapport  avac les  populations  de
dipteres  dans les lacs et les rivieres
ainsi que dans les regions littorales
et profondes des lacs d'eau douce.
Les conditions maxima que les popu-
lations de dipteres peuvent tolerer
dans  ces milieux  sont donnees ici
quand elles sont conneus.  On a tire
de cette etude plusieurs conclusions
generates.  Le travail sur le terrain
indique   qu'on  ne peut se servir
d'aucun  groupe  de diptere per se
comme organisme indicateur de pol-
lution.  Les  especes  Tendipes (T.)
EIN    UBERBLICK  UBER  DIE
ANFORDERUNGEN  DER   ZUCK-
MUCKE  (DIPTERA:  TENDIPEDI-
DAE) AN IHRE UMGEBUNG.  La-
Verne L. Curry,   p. 127 .  Es wird
eine  kurze Geschichte der  Taxono-
mie  und  der limnologischen Wieh-
tigkeit der Familie gegeben. Wenn
moglich  werden sinnverwandte Na-
men fur  die wichtigen Arten ange-
geben, damit  der Forscher seine
Ergebnisse mit denen aus  anderen
geographischen Gebietenverkniipfen
kann. Die Darstellungen der Anfor-
derungen der gewohnlich vorkom-
menden  Arten an  ihre  Umgebung
fussen hauptsachlich auf der Fauna
des  Staates  Michigan.   Soweit An-
gaben vorhanden sind,  werden die
Auswertungen  auf  die  holoarkti-
schen, neotropischen und aethiopi-
schen Gebiete ubertragen. Folgende
Umgebungsbedingungen werden be-
rucksichtigt:   Sauerstoff,  Kohlen-
dioxyd, Sulfide,Sulfite,Sauren,einige
organische Stoffe, pH, Temperatur,
Ablagerungen von Fasern und Ver-
schlickung.  Dann werden  auch im
Zusammenhang mitZuckmuckenvor-
kommen  als Umgebungsfaktoren so-
wohl stehende  als  fliessende Ge-
wasser und  seichte und tiefe Zonen
von Siisswasserseen in Betrachtge-
zogen.   Wenn bekannt,  werden die
jeweils besten Bedingungen fiir die
Miicken genannt.  Einige allgemeine
Schliisse konnen aus diesen Studien
gezogen werdden. Beobachtungen an
Ort  und  Stelle zeigten,  dass keine
Gruppe von  Zuckmiicken fur  sich
allein als Leitorganismus flir  Ver-
                                                       388

-------
are  restricted either to a lentic or
lotic environment. Others are known
to inhabit both environments.  In
addition, a few species are able to
adapt to the  physical and chemical
conditions imposed upon the organ-
isms in the  littoral and profundal
regions oi larger bodies of water.
In general, the conditions discussed
in this paper, when imposed upon
the midge fauna, have a detrimental
effect upon the population.
 riparius   (Meigen)   (=Chironomus
 riparius Meigen) et T. (T.) tentans
 (Fabricius)  (^Chironomus  tentans
 Fabricius) pourraient cepedant itre
 considere'es comme telles. Quelques
 especes de  cette famille  sont re-
 streintes  soit  aux lacs  soit aux
 rivieres.    On sait que  d'autres
 especes habitant les deux milieux.
 De plus, quelques especes peuvent
 s'adapter aux  conditions physiques
 et  chimiques imposees  aux
 organismes  dans  les regions lit-
 torales et profondes des grandes
 masses  d'eau.   En general, les
 conditions  etudiees dans ce travail,
 si  on  les  impose  a la faune de
 dipteres, ont des effets nuisibles sur
 la population.
 unreinigung angesehen werdenkann,
 dass aber die Arten Tendipes (T.)
 riparius (Meigen) = Chironomus ri-
 parius  (Meigen)  und T. (T.) tentans
 (Fabricius) = Chironomus tentans
 (Fabricius) als  solche angesehen
 werden kb'nnten.   Einige  Arten der
 Familie kommen entweder  nur in
 stehenden Oder in  fliessenden Ge-
 wassernvor,wahrend andere diese
 Unterscheidung   nicht   machen.
 Ausserdem kSnnen sich einige wenige
 Arten an die physikalischen und
 chemischen Bedingungen der seich-
 ten und tiefen Zonengrosserer Was-
 seransammlungenanpassen. Im all-
 gemeinen batten die Versuchsbedin-
 gungen, welche Gegenstand unserer
 Untersuchungen waren, einen nach-
 teiligen Einfluss  auf die  Zuckm'uk-
 kenfauna.
ACCUMULATION   OF  RADIONU-
CLIDES OF  AQUATIC INSECTS.
J. J. Davis,  p. 211.   The  section
of the Columbia River that is within
the  Hanford Reservation in  South-
eastern  Washington provides a
unique opportunity  for studying ac-
cumulation and cycling of radionu-
clides in natural aquatic communi-
ties.  Insects living  in the river
below  reactor outfalls are many
times  more  radioactive  than the
water they inhabit.  An organism's
location in the food web, its  trophic
level,  may  affect  the amount of
radionuclides accumulated.   Pro-
nounced  differences may occur in
the  amounts of radionuclides  ac-
cumulated  by different species of
insects from the same habitat. Radio-
nuclide   concentrations within a
species, however,  follow  definite
seasonal cycles. The concentration
of radionuclides in  plankton follows
essentially the same seasonal pat-
tern as  the  radionuelide cycle in
river water.  The  radioactivity in
insects, on the other hand, coincides
closely  to  the water  temperature
pattern.

   The influence of  isotopic dilution
upon phosphorus-32 accumulation in
aquatic  organisms  was studied by
introducing  the trace  amount  of
phosphorus-32 but differing quanti-
ties  of stable phosphorus, into each
of four troughs containing  estab-
lished stream-type ecosystems. The
results  indicated  a nearly  linear
reduction of phosphorus-32  uptake
with increase of phosphorus in the
water.
ACCUMULATION  DES RADIONU-
CLIDES  PAR  LES INSECTES
AQUATTQUES.   J. J. Davis, p. 211.
La section de la riviere  Columbia
qui se  trouve dans les limites de
la Reserve Hanford, dans le sud-est
de  1'Etat de Washington, presente
une  occasion  unique  d'etudier
1'accumulation  et  les  phenomenes
cycliques des  radionuclides  dans
les  communautes   aquatiques
naturelles.  Les insectes qui vivent
dans la riviere enavaldesexutoires
des reacteurs ont une  radioactivite
beaucoup  plus elevee  que  celle de
1'eau  qu'ils habitent. La place d'un
organisme dans la chatne alimen-
taire, son niveautrophique, pour rait
offecter la quantite de radionuclides
accumulSs.  On  peut  trouver  des
differences  marquees  dans les
quantites de radionuclides accumules
par  les  especes  differentes  d'un
meme habitat.   Les concentrations
de  radionuclides pour une espece
donnee subissent toutefois des vari-
ations saisonnieres definies.    La
concentration des radionuclides dans
le plancton suit essentiellement les
mSmes variations saisonnieres que
celles des  radionuclides dans 1'eau
de  riviere.  D'un  autre  cote,  la
radioactiviti  Chez  les insectes et
la temperature  de  1'eau  montrent
des  variations  semblables qui
coincident pratiquement.

   Pour  etudier  1'influence de la
dilution  isotopique  sur 1'accumu-
lation du phosphor-32  chez les or-
ganismes aquatiques, on a introduit
une quantite marquee de phosphore-
32, mais des quantites differentes
de phosphor stable dans chacunedes
quatre auges contenant des ecosys-
tlmes etablis du genre  riviere. Les
resultats ont indequl une diminution
presque lineaire dans 1'assimilation
du phosphore-32 a  mesure que le
phosphore augmente dans 1'eau.
 ANREICHERUNG VON RADIONUK-
 LIDEN DURCH IM WASSER LEB-
 ENDE  INSEKTEN.   J.  J. Davis.
 p. 211.  Der Abschnitt des Colum-
 biaflusses  innerhalb  des Hanford
 Sperrgebiets  im sudostlichen  Teil
 des Staates Washington bietet  eine
 einmalige  Gelegenheit zum Studium
 der Anreioherung  und des Kreis-
 laufs  von  Radionukliden  in nafur-
 lichen Gewassern.  Insekten, die im
 Fluss unterhalb des Reaktor^usfalls
 leben, sind viel radioaktiver als das
 Wasser,  das  sie  bewohnen.   Die
 Stellung eines Organismus im Nah-
 rungshaushalt  der  Natur und die
 Art  seiner    Nahrungsverwertung
 kSnnen den Betragderangesammel-
 ten Radionuklide beeinflussen.   We-
sentliche Unterschiede dieser Betrage
 konnen fttr verschiedene Insektenar-
 ten, auch solchen aus der gleichen
 Umgebung, auftreten. Innerhalb der-
 selben Art folgt die Radionuklidkon-
 zentration  bestimnten jahreszeit-
 lichen  Wechseln.   Die Radionuklid-
 konzentration im Plankton folgt im
 allgemeinen  dem  gleichen jahres-
 zeitlichen Bild wie  der Radionuklid-
 wechsel im  Wasser  des  Flusses.
 Die  Radioaktivitat der   Insekten,
 auf  der  andern   Seite,   fallt im
 wesentlichen  mit dem Wassertem-
 peraturgang zusammen.

   Der  Einfluss der  Isotopenver-
 diinnung auf  die Phosphor - 32 An-
 reicherung   in  Wasserorganismen
 wurde studiert, indem  eine Spur von
 Phosphor -  32, aber verschiedene
 Mengen von  stabilem Phosphor, in
 jeden von 4Trogeneingetragenwur-
 den,  welche bekannte  oekologische
 Typen Flusswasser enthielten.  Die
 Abnahme von  Phosphor  -  32  An-
 reicherung  war mit zunehmender
 Phosphorkonzentration im Wasser
 nahezu gradlinig.
                                                       389

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DISSOLVED  OXYGEN  REQUIRE-
MENTS OF FISHES. Peter Doudoroff
and  Charles E. Warren,  p. 145.
Dissolved oxygen concentration has
been  shown to influence markedly
the  maximum  or  active rates of
oxygen consumption and the sustained
swimming performance capabilities
of fresh-water fishes at any given
temperature.  When food supply is
unrestricted in laboratory  tests,
oxygen concentration influences
likewise the rates of food consump-
tion  and  of growth,  and  under
extreme  conditions, the gross ef-
ficiency  of  food  conversion.   The
rates of  embryonic  and larval de-
velopment, the size of larvae at the
times of hatching and of completion
of yolk absorption,  and so the ef-
ficiency of yolk utilization, also are
dependent on oxygen concentration.
The  effects of reduced concen-
trations on  embryonic development
vary not only with temperature, but
also with the  velocity of the water
which  determines the  rate of de-
livery of  oxygen  to  the chorion
surfaces.   Marked reductions of
active rates of oxygen consumption
by fish,  of maximum  sustained
swimming  speeds, and of  rates of
development, food  consumption, and
growth have been observed upon re-
duction of oxygen concentration to
levels only  slightly  below the  air-
saturation level.   The appetite and
the  growth rates  of  fish can be
greatly impaired  by wide diurnal
fluctuation of oxygen concentration.
The  impairment occurs even  when
the arithmetic or geometric mean
oxygen concentrations, i.e., the pro-
perly weighted means of the alter-
nating low and high concentrations to
which  the  fish are  exposed, fall
within the range of  most favorable
constant  concentrations and the dur-
ation of daily exposure to low con-
centrations is only one-third or one-
half of the 24-hour day. Abnormally
high concentrations  well above the
air-saturation  levels also can be
inhibitory.   Prompt avoidance re-
actions of fishes to reduced oxygen
concentrations well above those that
are lethal or cause obvious distress
have  been observed under experi-
mental conditions.

   The ecological significance of all
the above observations made in the
laboratory is not yet clear. Oxygen
concentrations  avoided  under some
experimental conditions may not be
avoided likewise under natural con-
ditions.  Swimming  speeds and de-
velopmental rates that are essential
to survival and unimpaired success
of fish in natural environments, as
well as  larval sizes that must be
attained at the time of hatching or of
complete  yolk  absorption  are un-
CONDITION D'OXYGENE DISSOUS
DBS POISSONS.   Peter Doudoroff
and  Charles E. Warren, p. 145 .
La  concentration d'oxygene dissous
a ete  montre pour  influencer les
taux maximum ou  actif de consom-
mation d'oxygene et la libre evolution
des  poissons  d'eau  douce  a  des
temperatures  donnees.    Quand
1'alimentation   en  nourriture  n'a
aucune  restriction dans lesessais
de  laboratoires,  la  concentration
d'oxygene influence  de  meme les
taux de consommation de nourriture
et les taux de croissance et sous
d'extre'me conditions la  grosse ef-
ficiencede conversion de nourriture.
Les taux dedeveloppementau niveau
des  embryons  et  des  larves, le
grandeurs des larves au  moment
de  1'eclosion  et  de  la complete
absorpiton  des oeufs  et aussi  de
1'efficience de 1'utilisation des oeufs
sont  aussi  dependant de  la con-
centration d'oxygene.   Les  effets
de concentration reduit sur le de-
veloppement embryonnaire varient
non seulement avec la temperature
mais  aussi  avec la vitesse de 1'eau
qui  determine le taux de delivrance
d'oxygene aux surfaces.  Les re-
ductions marques  de taux actif de
consommation  d'oxygene  par  le
poisson de  vitesse   devolution
soutenue et  de pourcentage de de-
veloppement  de consommation  de
nourriture et  de croissance ont ete
observl sous  la reduction de con-
centration  d'oxygene a  niveau
legerement  plus bas que le niveau
d'air  sature.  L'appetit et le pour-
centage de croissancedupoisson
peut 'etre grandement alter'es par de
fluctuation diurne  de concentration
d'oxygene.   Les alterations  per-
sistene meme quand  le  moyen  de
concentration  d'oxygene est  arith-
metique  ou  geometrique. Par
exemple,  les  moyens proprement
evalues dans 1'alternance des con-
centrations  hautes  et basses  a
laquelle les poissons sont exposes,
tombent dans  le domaine des con-
centrations  les plus favorable et la
duree  d'exposition journaliere aux
basses concentrations est seulement
le 1/3 ou la moitie  des 24 heures
du jour. Les hautes  concentrations
anormalement bien  au-dessus des
niveaux d'air  sature peuvent aussi
etre reprimees. Les reactions pro-
mptes du poisson  pour reduire les
concentrations d'oxygene de  celles
qui  sont lethal ou cause de detresse
evidente ont ete observe dans des
conditions experimentales.

   La  signification  ecologique  de
toutes les  observations faites ci-
dessous dans  le laboratoire n'est
pas encore  claire.  Les concentra-
tions  d'oxygene eVitees dans  des
conditions  experimentales  ne
FISCHE  UND  IHR  BEDARF  AN
GELOSTEM SAUERSTOFF.  Peter
Doudoroff und Charles E.  Warren.
p. 145  .   Es 1st bekannt, dass die
Konzentration des gelosten Sauer-
stoffs betrachtlich den Hochst - und
Aktivwert des Sauerstoffverbrauchs
und die Dauerschwimmleistung von
Siisswasserfischen bei jeder belie-
bigen Temperatur beeinflussen. Bei
unbeschrankter Nahrungsversorgung
in Laboratoriumsversuchen  wirkt
sichdie Sauerstoffkonzentation auch
auf Raten des Nahrungsverbrauchs
und des Wachstums und unter Grenz-
bedingungen auf die  Stoffwechsellei-
stung selbst  aus.   Die  Raten der
Embryonal - und Larvenentwicklung,
die Larvengrossezur Zeitdes Aus-
schliipfens, die Vollstandigkeit  der
Dotterabsorptionunddamitdie Lei-
tungsfahigkeit der Dotterausnutzung
hangen ebenfalls vonder Sauerstoff-
konzentration  ab.    Die  Einflusse
geringerer Konzentrationen auf die
Embryonalentwicklung andern  sich
nicht nur  mit der Temperatur, son-
dern  auch   mit   der   Wasser-
geschwindigkeit, das diese die  Ge-
schwindigkeit der  Sauerstoffabgabe
an die Choionoberflache bestimmt.
Bedeutende Verminderungen der ak-
tiven Raten des Sauerstoffverbrauchs
der  Fische, der hochsten Dauer-
schwimmgeschwingigkeiten,    der
Entwicklungsraten,  des  Nahrungs-
verbrauchs unddes Wachstumswur-
den beobachtet, wenndieSauerstoff-
konzentration nur sehr wenig unter
den  Luft  - Sattigungsstand herab-
gesetzt wurde.  Appetitund Wachs-
tums raten   yon  Fischen  konnen
durch  weite tagliche  Schwankungen
der  Sauerstoffkonzentration  sehr
beeintrachtigt werden. Die Schadi-
gung tritt  sogar  dann  auf, wenn
die  arithmetischen  Oder  geomet-
rischen Mittel der  Sauerstoffkon-
zentrationen (d.h.  die richtig ge-
werteten  Mittel  der abwechselnd
niedrigen und hohen  Konzentratio-
nen, welchen die  Fische  ausgesetzt
sind) in die Reihe  der gunstigsten
Dauerkonzentrationen fallen und die
Fische nur  fur  etwa  ein Drittel
Oder  die  Ha'lfte des  24 -  Stunden-
tages   solch  niedrigen  Konzen-
trationen  ausgesetzt  sind.  Abnor-
male Konzentrationen, betrachtlich
iiber den  Luftsattigungswerten kon-
nen ebenfalls hemmend wirken. Un-
verzligliche Ausweichreaktionen der
Fische  im   Bereiche  geringerer
Sauerstoffkonzentrationen.auchwenn
solche  bestimmt oberhalb  der tod-
lichen Konzentrationen lagen oder
augenscheinlich Unbehagen verur-
sachten,  wurden  unter den Bedin-
gungen der  Versuche  beobachtet.

   Die oekologische Bedeutungaller
angefuhrten Beobachtungen ist noch
nichtklar.Unter gewissen Versuchs-
                                                       390
                                                                                                       GPO 816-361 — 1

-------
known, but presumably can be de-
termined experimentally. The criti-
cal  oxygen  concentration for  in-
cipient impairment of growth under
natural conditions probably depends
on the availability of food, which may
itself be  the major  factor limiting
growth rates.   This  critical con-
centration may well depend also on
the  rate  at which energy must be
expended by the fish in seeking and
capturing available food, while also
escaping enemies, etc. The appetite
of the fish or the activity that pre-
sumably is necessary for food pro-
curement, or both, evidently must be
reduced when available oxygen be-
comes insufficient for supporting all
metabolic processes at  normal
levels. Accordingly, a satisfactory
laboratory model  for studies of the
dissolved  oxygen  requirements of
fish, directed toward reliable esti-
mation of critical concentrations at
which incipient impairment of growth
would  occur  in  a  given  natural
environment, cannot ba a very simple
one.  Evidently it  must combine the
food ration normally obtainable
under  favorable  dissolved  oxygen
conditions in the natural environ-
ment with enforced activity approxi-
mately equivalent  to the spontaneous
and  other activity that under  the
natural conditions would be essential
for  survival  and normal feeding.
This conclusion applies also to the
study  of  other water-quality re-
quirements of fishes.
peuvent e*tre evitees de mtme dans
des conditions naturelles. Lavitesse
devolution et les tauxdedeveloppe-
ment qui sont essentiels  pour  la
survie et la nonalte'rationdu poisson
dans des milieux naturels aussi Men
que  la  grandeur  des  larves qui
doit etre atteinte a 1'eclosion au la
complete absorption des oeufs sont
inconnue,  mais  peuvent £tre de-
termine  experimentallement.   La
concentration  d'oxyge'ne  pour
1'alteration de  croissance dans des
conditions  naturelles depend pro-
bablement  de la  disponibilite'de la
nourriture  qui peut elles-meme etre
le facteur  majeur de limitation du
taux de croissance. Cette concen-
tration critique peut bien dependre
aussi du  taux d'energie depense par
le poisson  pour capturer la nourri-
ture et aussi echapper auxennemis,
etc.  L'appetit du poisson oul'activ-
ite qui probablement est necessaire
pour le procurement da  la nourri-
ture ou pour les deux evidemment
peut  &tre  reduit quand 1'oxygeVie
disponsible devient insuffisant pour
supporter tous  les precedes meta-
boliques  aux niveaux normaux.  En
consequence  un modele de labora-
toire satisfaisant pour les etudes de
condition d'oxyge'ne dissous par le
poisson dirige vers 1'estimationdes
concentrations  critiques  i laquelle
1'alterations  de la  croissance sur-
viedrait dans un milieu natur el donne
ne peut etre pas une tres simple re-
alisation.  Evidemment,  il peut
combiner la ration de nourriture
normalement obtenu sous des con-
ditions d'oxygene dissous favorable
dans le milieu naturelavecl'activite'
approximativement equivalente  et
autres activates  qui sous les con-
ditions naturelles seraient essenti-
elles pour 1'alimentation normale et
la survie.   Cette conclusion s'ap-
plique  aussi &  1'etude des autres
conditions de qualit£ d'eau en rapport
avec le poisson.
bedingungen wurden Sauerstoffkon-
zentrationen vermieden, die in der
Natur   nicht  vermieden  wurden.
Schwimmgeschwindigkeiten, welche
fur das  Uberleben  und den unge-
hinderten Erfolg der Fischeinihrer
natiirlichen    Umgebung notwendig
sind,  Larvengrossen,  welche zur
Zeit des   Ausschlupfens  erreicht
werden  mussen Oder vollkommene
Dotterabsorption   sind  unbekannt,
vermutlich   aber  experimenteller
Bestimmung  zuganglich.  Die kri-
tische  Sauerstoffkonzentration fur
beginnende    Wachstumshemmung
unter natur lichen Bedingungen h'angt
wahrscheinlich von der verfugbaren
Nahrung ab, die selbst einwichtiger
Faktor  in der  Beschrankung der
Wachstumsraten sein kann.  Diese
kritische  Konzentration kann auch
von dem Masse abhangen, in wel-
chem Energie von den Fischen zum
Suchen und Fangen der verfiigbaren
Nahrung Oder  zur Vermeidung von
Feinden usw. aufgewendet wird. Der
Appetit  der  Fische oder die Tatig-
keit, vermutlich nbtig zur Nahrungs-
beschaffung,   Oder  beide,  mussen
augenscheinlich  verringert werden,
wenn der verfflgbare Sauerstoff zum
Unterhalt aller Stoffwechselvorgange
in normalem Massstab  ungeriugend
wird.    Infolgedessen kann ein zu-
friedenstellendes   Laboratoriums-
modell  zum  Studium des  Bedarfs
von Fischen an gelostem Sauerstoff,
das zuverlassig die kritischen Kon-
zentrationen fur beginnende Wachs-
tumsschadigung in einer naturlichen
Umgebung bestimmen liesse, nicht
sehr einfach sein.  Augenscheinlich
mu'sste es die normal unter gunstig-
en Konzentrationen gelosten Sauer-
stoffs erhaltliche Nahrungsmenge in
der naturlichen  Umgebung mit er-
zwungener   Tatigkeit  vereinigen,
welch letztere ungefahr gleich der
unter denselben Bedingungen fur das
Uberleben   und   <(die    normale
N \hrungj3aufnahme notigen Tatigkeit
sein musste.   Dieser  Schluss  ist
auch fur das Studium anderer An-
forderungen,  welche Fische an die
Gute des  Wassers  stellen,  giiltig.
EFFECTS OF OIL POLLUTION ON
MIGRATORY BIRDS.  Ray C. Erick-
son. p. 177.  The loss of migratory
birds due to  oil pollution has been
a perpetual problem in the manage-
ment of this  resource.  Because of
their attraction to or  dependence
upon  aquatic  environments, many
migratory birds  are subject to
factors that  adversely  affect the
habitability of these environments.

   The oil pollution problem is most
critical during the cold months, for
at that time migrating birds pass
through or  concentrate  upon the
INFLUENCE DE  LA POLLUTION
PAR LES HUILES SUR LES OISEAUX
MIGRATEURS.   Ray C. Erickson.
p. 177.  La perte  d'oxieaux migra-
teurs par suite de pollution par des
huiles a ete  un probleme continu
pour  1'amenagement de  ces res-
sources. En raison de leur attraction
ou  de leur dependance  vis a vis
des  milieux aquatiques,  beaucoup
d'oiseaux migrateurs dependent de
facteurs affectant defavorablement
1'habitat de ces milieux.

   Le probleme de la pollution par
les huiles est tres critique pendant
EINFLUSS VON WASSERVERUN-
REINIGUNG  MIT b"L AUF ZUG-
VOGEL.  Ray C. Erickson.  p. 177.
Der  Verlust von  Zugvogeln..durch
Wasserverunreinigung mit  Ol  ist
ein dauerndes Problem in der Be-
treuung diese Naturschatzes. Viele
Zugvogel sind, weil sie durch Wasser
angezogen  werden Oder  davon ab-
hangen, jenen Faktoren ausgesetzt,
welche  die Bewohnbarkeit dieser
Umgebung  ungiinstig beeinflussen.

   Die. Frage der Verunreinigung
mit  Ol    ist wahrend der kalten
Monate 'ausserst kritisch, weil dann
                                                       391

-------
•waters or shorelines where oil may
be spilled or  to which it may drift,
and  death  from  exposure may be
rapid.  Although oil  contamination
may occur inland from time to time,
relatively small numbers of migra-
tory birds ordinarily are affected
by it because fewer birds are ex-
posed or because the quantities of
oil  involved  are  less.  Along the
shores of North America, expecially
the Atlantic and Gulf coasts, migra-
tory bird feeding and resting areas
are subjecttooilcontaminationfrom
sea-going vessels and shore instal-
lations.  Continuing oil pollution is
encountered at a few locations, but
the most spectacular losses usually
have  occurred as a result of the
escape of oil from storm- and col-
lision-damaged  or sunken vessels
along the coast.

   All birds frequenting oil-polluted
shores and waters may be  subject
to oil contamination.  Just a few
drops of oil coming in contact with
the plumage may destroy its water-
proof nature  and subject the bird
to exposure  or, if the  oil  is in-
gested, may have toxic effects in the
digestive tract. Birds appear to be
attracted  to  oil, presumably be-
cause of the quieting effect of the
oil  on choppy waters.  Thus, the
adverse effects of even a small oil
slick may be much more important
than its relatively limited area might
lead one  to  expect,  and when the
area is frequented by large numbers
of  migrating  or  wintering  birds,
heavy mortality may result.

   The only complete remedy to the
problem is elimination of all sources
of oil that  contaminate migratory
bird  habitats.    Although zealous
enforcement  of the  terms of the
International  Convention  for the
Prevention of Pollution of the Sea
by  Oil, 1954,  and strict  controls
over oil  spillage or discharge into
coastal waters should substantially
reduce  this  problem, a  complete
solution in the foreseeable future can
hardly be expected.   Accidental
spillage  over  which there is little
or no control undoubtedly will con-
tinue,  and  both unintentional and
deliberate  pollution will probably
occur in spite  of  the strictest en-
forcement of protective measures.
It is possible that research into this
problem  might  reveal methods of
repelling  birds from oil-contami-
nated water.   Until such techniques
are  developed,  however, the only
remedy consists of capturing, de-
contaminating, and rehabilitating the
birds by  laborious  and time-con-
suming methods; the number of birds
salvaged by these methods  usually
is small compared with the number
that perish.
les mois froids car c'est le moment
ou lex oiseaux migrateurs passent
ou bien se rassemblent sur lexeaux
o-j sur les rivages; de 1'huile peut
y  etre  repandue  ou y avoir  ete
entrainee, de sorte que la mortpeut
etre rapide.   Quoiqu une contami-
nation par  des  hules  puisse se
presenter de  temps en temps  sur
terre, relativement  peu  d'oiseaux
migrateurs  en sont affectes, soit
parceque peu  d'oiseaux y  sont  ex-
poses, soit p^arceque les quantites
d'huile  entratnees  sont moindres.
Le long des plages de 1'Amerique
du Nord, particulierement des cotes
de 1'Altantique et de Gulfe, les zones
de  rivitaillement et de repos  des
oiseaux migrateurs sont sujettes aux
contaminations   par  les  hydro-
carbures provenant  a la  fois  des
navires  en circulation  et  des in-
stallations cotieres.  Une pollution
permanente  existe  en   quelques
endroits, mais  les  mortalite's les
plus spectaculaires ont eu lieu a la
suite soit d'un orage avec collision
et  echappement    d'huile,  soit de
maufrage de bateaux le long de la
cote.

   Tous  les oiseaux f requentant les
rivages et les eaux polluees par des
huiles  peuvent   etre  sujets  a  la
contamination.    Quelques gouttes
d'huile settlement venant en contact
avec le plumage de 1'oiseau peuvent
detruire son impermeabilite  et ex-
poser 1'oiseau a 1'huile ou, si 1'huile
est  absorbee, peuvent avoir  des
effets  toxiques  sur  1'appareil
digestif.    Les  oiseaux  semblent
attires par 1'huile, sans doute en
raison de 1'effet calmant de 1'huile
sur les eaux agitees.   Aussi les
effets dangereuxd'une nappe h'huile,
me'me petite, peuvent Itre beaucoup
plus  importants  que  sa  surface
limitee ne paurrait le laisser sup-
poser et, guand  la  region est fre-
quentee  par de nombreaux oiseaux,
une mortalite importante peut en
resulter.


   Le seul reme'de completauprob-
leme  est  1'elimination  de  toutes
sources  d'huile pouvant contaminer
les habitats des oiseaux migrateurs.
Quoique 1'application rigouseuse des
termes  de  la  Convention  Inter-
nationale pour la protection  de la
mer contre  la pollution par hydro-
carbures de 1954 et des contrSle;
stricts des  deversements de'huile
dans  les  eaux  cotieres   doivent
reduire sensiblement ce probleme,
une solution complete peutdifficile-
ment  etre  esperee dans un avenir
proche.   Les ecoulements ac-
cidentels qui ne peuvent etre con-
troles  ou  tres   peu, continueront
et des  pollutions  aussi bien  in-
volontaires  que  deliberees auront

              392
 die  Zugvogel auf ihrer Wanderung
 sich  auf den  Gewassern Oder  an
 den Ufern ansammeln und dort ver-
 schuttetes  Oder  angetriebenes  01
 ihren raschen Tod zur Folge haben
 kann.   ^Obwohl   Verunreinigungen
 durch  "(5l  von  Zeit zu  Zeit  auch
 im Innern des  Landes vorkommen,
 so sind   doch  dann  gewohnlich
 weniger Zugvogel dadurch  gescha-
 digt,  well rtie  Zahl der Vogel ger-
 inger ist und weil auch die Slmen-
 gen nicht so bedeutend sind. Langs
 der Kiisten von Nordamerika, be-
 sonders am Atlantischen Ozean und
 im Golf  von Mexiko, sind die von
 Zugvogeln  benutzten Futter  - und
 RuheplStze   der    Verunreinigung
 durch '6l von  Seeschiffen  und von
 gewissen Kustenanlagen unterwor-
 fen.  Dauerverunreinigung durch 01
 tritt  an  einigen Stellen  auf; am
 meisten  fallen  jedoch gewohnlich
 die  Verluste  auf,   welche  durch
 Olverlust aus  sturm - Oder   zu-
 sammenstossbeschadigten Oder aus
 gesunkenen Schiffen herrtihren.

   Alle  Vogel konnen  sich mit 01
 beschmatzen, wenn sie damit verun-
 reinigte Kiisten oder Gewasser auf-
 suchen.  Einige wenige Tropfen 01
 konnen die wasserabweisende Natur
 des Gefieders  zerstoren;  mit der
 Nahrung  aufgenommenes   01  kann
 Giftwirkungen  im Verdauungskana.1
 ausl'osen.   Vogel scheinen durch 01
 angelockt  zu  werden,  moglicher-
 weisg wegen der glattendenWirkung
 des Ols auf die Wasserflache.  So
 kSnnen die nachteiligen Wirkungen
 eines nur kleinenOlflecksvielwich-
 tiger sein als seine geringe Ober-
 flachenausdehnung vermuten liesse
 und wenn  die  Gegend von einer
 grossen Anzahl von Zugvogeln oder
 uberwinternden VSgeln besucht wird,
 dann  kann  eine hone Sterblichkeit
 die Folge sein.

   Das  Problem der Verunreinigung
 durch   01    kann nur  durch  voll-
 kommene Ausschaltung aller Ursa-
 chen erreicht werden. Obwohlpein-
 lich genaue Befolgung  der  Regeln
 des Internationalen liber einkommens
 zur  Verhinderung der  Verunreini-
 gung des Meeres durch 01 vom Jahre
 1954  und  strenge  Kontrolle  uber
 verschuttetes 01 oder dessen  Ein-
 leitung in Kustengewasser das Prob-
 lem bedeutend verringern,  so kann
 doch eine vollstandige Losung nicht
 so bald erwartet werden. Zufalliges
 Verschutten kann nur  wenig  oder
 gar  nicht  verhindert  werden  und
wirdzweifellos fortbestehen und un-
 absichtliche oder absichtliche Ver-
unreinigung  wird   wahrscheinlich
trot?; strengster Schutzmassnahmen
vorkommen.  Moglicherweise wer-
den weitere  Studien des Problems zu
einern^  Verfahren fuhren, welches
die Vogel von olverunreinigten Ge-
                                                                                                    GPO 816-361-15

-------
   Dramatic  and pathetic  as pol-
lution-caused  losses may be, dam-
age  to the  habitat may  be  even
more lasting in its effects on wild-
life  populations.  Toxic influences
of oil on plants and animals  that
directly or indirectly are important
to migratory birds may far outweigh
observable bird  losses.   Habitats
are vulnerable to pollution through-
out the year  rather than just a few
months during the fall, winter, and
spring.  Little is known regarding
the duration or  over-all chemical,
mechanical, or biological effects of
the oily  residues that  continue to
accumulate and  blanket the bottom
with  sludge,  or  of  methods  that
might  be used to restore the con-
taminated areas to fullproductivity.
probablement lieu en depit de  la
plus stricte application des mesures
de protection.  II est possible que
des  recherches  sur  ce  probleme
revelent des  methodes permettant
d'eloigner  des oiseaux contamines.
Cependant, jusqu a ce que de telles
techniques soient  trouvees, le seul
remede consiste a capturer, decon-
taminer  et retablir les oiseaux par
des methodes longues et laborieuses,
le nombre d'oiseaux sauves par ces
moyens^est normalement petit,
compare  au nombre  de  ceux qui
psrissent.

   Aussi dramatiques etpathetiques
que puissent etre les pertes causees
par  la  pollution,  les dommages
portes  £ 1'habitat peuvent  etre
encore  plus  durables dans leurs
effets  sur  la vie des animaux
sauvages.  Les influences toxiques
de  1'huile  sur les plantes et lex
animaux qui,  directement ou  indi-
ractement, interviennent dans la vie
des  oiseaux  migrateurs, peuvent
depasser  de  beaucoup les pertes
visibles d'oixeaux. Les habitats sont
vulverables a la pollution  toute
1'annee et nonquelques mois d'hiver.
On  sait peu de choses sur la duree
des effets chimiques, mecaniques ou
bioligiques des residus huileux qui
s'accumulent et recouvrent les fonds
avec la vase ou  sur  les  methodes
permettant de remettre en etat les
zones contaminees.
 wassern abstosst.   Aber bis zur
 Entwicklung  solcher  Methoden be-
 steht das einzige Heilmittel darin,
 die Vogel in anstrengendenundzeit-
 raubenden Verfahren zu fangen, zu
 reinigen  und  dann wieder  freizu-
 lassen; die Zahl der auf dieseWeise
 geretteten Vogel   ist gewohnlich
 gering im Verhaltnis zur  Zahl der
 Verluste.

    Dramatisch und  erschutterndwie
 diese durch  Verunreinigungen her-
 vorgerufenen Verluste sein mSgen,
 der  Schaden  an den von den Vogeln
 besuchten  Gegenden dauert fort in
 seinem Einfluss. Giftwirkungen von
 01 auf Pflanzen und Tiere, welche
 mittel -  Oder unmittelbar wichtig
 fiir  Zugvb'gel  sind,   konnen  die
 beobachtbaren Verluste an Vogeln
 weit iiberwiegen.   Wohnplatze sind
 wahrenddesganzen Jahres empfind-
 lich fiir Verunreinigungen und nicht
 nur im Herbst, Winter und Frlihling.
 Man weiss nur sehr wenig liber die
 Dauer  der chemischen,  mechani-
 schen oder  biologischen_ Gesamt-
 wirkungen    der   Olrucksfande,
 welche sich fortwahrend ansammeln
 und  die  Boden der Gewasser mit
 Schlamm bedecken oder uber Ver-
 fahren, welche die verunreinigten
 Gebiete wieder zu  voller Ertrags-
 fahigkeit bringen konnten.
SOME  REMARKS ON A NEW SAP-
ROBIC SYSTEM.  E. Fjerdingstad.
p. 232  .   A system of grouping to
show the relationship of each species
to pollution places organisms in four
groups: (1) saprobiontic, those oc-
curring in large numbers only in
heavily polluted waters;  (2) sapro-
philons, those occurring generally in
polluted waters but which may occur
elsewhere; (3) saproxenons, those
generally  not  occurring in polluted
waters; and (4) saprophobons, those
not surviving in polluted waters. In
the system emphasizing community
aspects of organisms, the polysap-
robic zone is divided into three zones
and "coprozoic" designates the zone
for undiluted faecal water.  There
are nine zones, each with its com-
munity of algae and other organisms.
DES  REMARQUES  SUR   LE
NOUVEAU SYSTEMS SAPROBIQUE.
E. Fjerdingstad. p. 232. Unsysteme
de  groupement  en qautre groupes
pour  montret la relation de chaque
espece sur les organismes dans les
places polluees.   (1) Saprobiontic
survenant  en grands nombre dans
les eaux fortement polluees.   (2)
Saprophobons survenant generale-
ment  en eaux polluees mais pouvant
survenir  en d'autres  places.   (3)
Saproxenons ne survenant generale-
ment  pas en eaux polluees.   (4)
Saprophobons,  ceux,  ne survenant
pas  en  eaux  polluees.   Dans  le
systeme insistant  sur  1'aspect de
communate des organismes, la zone
^polysaprobic» est divisee en trois
zones et«coprozoic>>designe la zone
de 1'eau faecale indiluee. Ilyaneuf
zones, chancune avec sa communate
d'algues  et d'autres  organismes.
 EINIGE BEMERKUNGEN UBER EIN
 NEUES SAPROBIENSYSTEM.   E.
 Fjerdingstad.  p. 232 .  Bin Eintei-
 lungssystem, das die Verwandtschaft
 jeder Art zu Verunreinigungen zei-
 gen soil, bringt die  Organismen in
 vier Gruppen unter:  1) saprobion-
 tisch, in grosser Zahl nur in stark
 verunreinigten Wassern   vorkom-
 mend; 2)saprophil, kommen  im all-
 gemeinen in verunreinigten Wassern
 vor,  werden aber  auch anderswo
 gefunden; 3) saproxenone, treten im
 allgemeinen   in    verunreinigten
 Wassern nicht auf; 4) saprophobone,
 welche  in  verunreinigten Wassern
 nicht  leben kbnnen. In diesem Sys-
 tem,  welches    das gleichzeitige
 Auftreten  verschiedener  Organis-
 men betont, wird die Polysaprobien-
 zone  in drei  Zonen unterteilt  und
^koprozoisch" bezeichnet die Zone
 unverdiinnten Fakalwassers.  Man
 unterscheidet im ganzen  9  Zonen,
 jede mit ihrer  eigenen Gruppe  von
 Algen und anderen Organismen.
                                                       393

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THE  IMPORTANCE  OF  EXTRA-
CELLULAR PRODUCTS OFALGAE
IN THE AQUATIC ENVIRONMENT.
G.E.  Fogg.  p. 34  .  A variety of
organic substances may be liberated
into the medium from healthy algal
cells in laboratory culture, and there
is evidence that  similar extracel-
lular products are released, some-
times in relatively  large amounts,
in nature.  These  extracellular pro-
ducts may have various effects of
biological  significance  in aquatic
habitats, e.g., chelation of ions or
enzymic decomposition of organic
substances.  The liberation of gly-
collic acid as an extracellular pro-
duct of photosynthesis  may  be of
particular  importance.  The pres-
ence of a low concentration of  this
substance in the  medium has been
found to be necessary for the growth
of a planktonic Chlorella, and there
are indications that dissolved gly-
collic acid may act as  a substrate
for heterotrophic growth of micro-
organisms in freshwater.
L'IMPORTANCE  DES  PRODUITS
EXTRACELLULAIRESDESALGUES
DANS  LE  MILIEU  AQUATIQUE.
G.  E.  Fogg.   p. 34  .   Dans les
cultures  de laboratoire, des algues
saines peuvent  liberer dans leur
milieu environnant toute une variete
de substances organiques. Lameme
chose se produitaussi dans la nature
ou des produits extracellulaires
semblables  peuvent  etre  liberes,
parfois  en  quantites relativement
grandes.  Ces produits extracellu-
laires  peuvent avoir des  effets de
signification  biologique variee sur
les habitats, par example: chelation
d'ions, ou la decomposition des sub-
stances organiques par les enzymes.
La liberation  d'acide  glycollique
comme produit extracellulaire de la
photosynthe'se peut  avoir  une im-
portance toute particuliere. Lapre-
sence  d'une petite quantite de cette
substance dans le^jnilieu est neces-
saire a la croissance d'une Chlorella
du  plancton, et de  plus il semble
que  1'acide  glycollique d i s s o u s
pourrait aussi  servir de  base a la
croissance  heterotrophique des
microorganismes dans 1'eau douce.
DIE  WICHTIGKEIT VON EXTRA-
ZELLULAREN   ALGENPRODUK-
TEN  IM WASSER.  Gordon Edward
Fogg.  p. 34  .  Eine Vielheit von
organischen  Substanzen   kann in
einer Laboratoriumskultur von ge-
sunden Algenzellen in ihre Umgebung
abgegeben werden und man hat Be-
weise dafur,  dass ahnliche extra-
zellulare  Stoffe auch in der Natur,
manchmal sogar in relativ grossen
Mengen,   ausgeschieden   werdem..
Diese Stoffe  konnen verschiedene
Wirkungen von biologischer Bedeu-
tung im Wasser haben, z. B. Chela-
tion von lonen Oder enzymatischen
Abbau organischer Stoffe. Das Frei-
werden   von   Glykolsaure  als ein
extrazellulares  Produkt der Photo-
synthese  konnte von  besonderer
Wichtigkeit sein.  Es wurde gefun-
den, dass  eine  niedere Konzentra-
tion dieser Sa'ure fur das Wachstum
einer Plankton Chlorella notwendig
1st und es scheint, dass Glykolsaure
in  Lbsung als  Substrat  fur  das
heterotrophe Wachstum von Mikro-
organismen in Silsswasser wirkt.
RELATIONSHIPS BETWEEN  THE
CONCENTRATION  OF  RADIONU-
CLIDES  IN COLUMBIA  RIVER
WATER AND FISH.   R.  F.  Foster
and  Don McConnon.  p. 216 .   The
relationship between the concentra-
tion  of  radionuclides  in  water and
in fish used for food is a necessary
consideration in the release of radio-
active  wastes  to  surface  waters.
Actual  field observations  provide
good reference  data  and clues to
the  mechanisms involved  in the
transfer of the nuclides from the
water to  the fish.    A few radio-
auclides are concentrated  in  fish
to such an extent that human con-
sumption  of the fish is  the factor
that  limits the release rate.

   Downstream  from  the  Hanford
reactors, chromium-51,arsenic-76,
and  neptunium-239  are the  most
abundant nuclides in Columbia River
water, but these are  relatively un-
important  in the fish.  The bio-
logically  important radioelements,
phosphorus-32 andzinc-65,arepre-
sent in relatively low concentrations
in the river, but are dominant in the
fish.   The uptake  of  radionuclides
by fish can change markedly with
the  season of  the year  and the
most pronounced variations occur
with relatively  short-lived nuclides
acquired  via a food  chain.  Wide
RELATIONS  ENTRE  LA CONCEN-
TRATION  DE   RADIONUCLIDES
DANS  LE POISSON ET L'EAU DU
FLEUVE COLUMBIA.  R.  F. Foster
and  Don McConnon.   p.  216.  La
relation  entre  la concentration de
radionuclides   dans   1'eau  et  le
poisson utilise pour le nourritureet
une  consideration  necessaire  au
sujet  de  la de charge de dechets
radioactils dans les  eaux de sur-
face. L'actuel champs d'observation
produit de  bonnes donnees de ref-
erence et un  indice des mecanismes
entraines dans  la  transfert  des
nuclides de  1'eau au poisson. Peu
de  radionuclides  sont concentres
dans le poisson a tel point que la
consommation humaine du poisson
est  le facteur qui limite le taux
de decharge.

   Descendant  le fleuve  a  partir
desreacteursd'Hanford,chrome-51,
arsenic-76,  et neptunium-239 sont
les nuclides les plus abondants dans
1'eau de fleuve Columbia, mais ceux-
ci  sont relativement tres peu im-
portant dans le poisson.   Les
radioelements biologiquement im-
portants, phosphore-32  et zinc-65,
sont presents en une relative basse
concentration dans la riviere mais
sont  dominants  dans  le poisson.
L'aptitude pour  absorber des
radionuclides  pour   le   poisson
BEZIEHUNGEN  ZWISCHEN  DER
KONZENTRATION  VON   RADIO-
NUKLIDEN  IM WASSER  UND IN
DEN  FISCHEN DES  COLUMBIA-
FLUSSES.   Richard F. Foster and
Dan McConnon.    p. 216  .   Die
Beziehung zwischen der Konzentra-
tion von Radionukliden im Wasser
und in Fischen, die als Nahrungs-
mittel   dienen,  1st eine   wichtige
Erwagung  hinsichtlich der  Ent-
leerung radioaktiver Abfallstoffe in
Oberflachenwasser. Beobachtungen
an  Ort und  Stelle  geben  gute Be-
zugsdaten  und  Hinweise   auf  den
Mechanismus  bei der Ubertragung
der  Nuklide vom  Wasser auf die
Fische.   Einige Radionuklide  sind
in Fischen so stark angehauft, dass
Fischgenuss durch den Menschen
der die Entleerungen von radioakti-
ven  Abfallstoffen     begrenzende
Faktor geworden 1st.

   Flussabw'arts  von  den  Hanford
Reaktoren sind Chrom - 51, Arsen-
76 und Neptunium -  239 die haufig-
sten Nuklide  im   Columbiafluss-
wasser, aber  diese drei sind ver-
haltnismassig unwichtig fur Fische.
Die  biologisch wichtigen  Radio-
elemente Phosphor  - 32 und Zink -
65 sind im Flussinverhalnismassig
geringen Konzentrationen vorhanden,
aber vorherrschend in den Fischen.
Die  Aufnahme der  Radionuklide
                                                       394

-------
 variations between individual speci-
 mens necessitate large numbers of
 samples  for  valid  interpretation.
PHYSIOLOGICAL CONSIDERATIONS
IN  STUDIES OF  THE  ACTION OF
POLLUTANTS    ON   AQUATIC
ANIMALS. Paul O. Fromm. p. 316,
To  assess properly the effects of
water pollutants on aquatic animals,
long-term studies should be carried
out in which non-acutely lethal con-
centrations  of  toxicants are used.
Specific physiological parameters of
a chemical, a morphological, or a
histopathological  nature  are  sug-
gested and examples given of their
use.   In  addition, a more general
approach  to the assessment of the
effect  of  pollutants on aquatic
animals  is  discussed.   This pro-
cedure  involves  measurement  of
the  general  metabolism  (oxygen
consumption) of assay animals and
is based on the assumption that no
matter what environmental stress
is placed on an animal, it will be
reflected  in a change  (increase or
decrease) in normal metabolic rates.
Advantages and disadvantages of the
two approaches to the study of water
pollution are discussed.
ENVIRONMENTAL REQUIREMENTS
OF PLECOPTERA.ArdenR.Gaufin.
p. 105 .  While Plecoptera (stone-
flies) constitute  one of the smaller
orders of insects, they are neverthe-
less one of the most important groups
found in many streams. In mountain
streams, they are a principal source
of food for trout.  Brinck reported
that streams in  Sweden with dis-
solved oxygen concentrations  below
40 percent saturation had no stone-
flies.  Because of their preference
for clean, well-aerated water, they
are becoming increasingly important
to limnologists as indicators of clean
water  conditions in pollutional
surveys.

   Practically all of the work that
has been done to date on the  North
American stoneflies has dealt with
their  taxonomy  and  morphology.
Despite the work that has been done,
the nymphs of over 50 per cent of our
North American  species  have not
 change  considerablement  avec la
 saison  de 1'annee.   Les  grandes
 variations entre les specimens in-
 dividuels  necessitent un grandnom-
 bre  d'echantillons pour une  inter-
 pretation  valide.
CONSIDERATIONS   PHYSIOLOGI-
QUES  DANS   LES  ETUDES  DE
L'ACTION DES POLLUANTS SUR
LES  ANIMAUX   AQUATIQUES.
Paul  O.  Fromm.   p. 316 .  Pour
evaluer proprement les  effets  des
polluants de 1'eau sur les animaux
aquatique, des etudes a long termes
seraient  mis  a execution dans
lequelles  une   concentration  non
aigue de toxiques  est  utilise.  Les
parametres   physiologiques   d'un
produit chimique,  une  nature mor-
phologique ou histopathologique sont
suggeres et des exemples donnes de
leur utilite.    En  addition une  ap-
proche plus generale pour 1'evalu-
ation de 1'effet des polluants  sur
les animaux aquatiquesestdiscutee,,
Cette methode  implique  la mesure
du  metabolism general (consom-
mation  d'oxygene)  des  animaux
d'essais et est basee sur 1'hypothese
que si aucun milieu n'est place avec
un animal il sera reflechi dans un
changement  (croissant ou decrois-
sant) en  vitesses  metaboliques
normales.   Les  avantages  et  les
desavantages des deux approchesde
1'etude de pollution de  1'eau sont
discutees.
CONDITIQN DE MILIEUX AMBIANT
DES PLECOPTERA.   Arden R.
Gaufin.  p. 105 .   Tandis que les
Plecoptera constituent un des plus
petits genres d'insecte,   ils  sont
neammoins un des plus importants
groupes trouve dans beaucoup   de
cours d'eau,  Dans les cours d'eau
de  montagne  ils sont une  source
principals  de nourriture  pour les
truites.  Brinck a rapport! que les
cours  d'eau  en  Suede  avec  des
concentrations d'oxygenedissous en
dessous  de  40% de  saturation
n'avaient pas de Pl&coptera.  Du
fait  de leur  preference pour 1'eau
propre  et  bien  oxygene ils  sont
devenus de plus en plus important
aux yeux des limnologistes, comme
des  indicateurs de condition d'eau
propre  dans les examens de pol-
lution.
   Pratiquement tous les travaux qui
ont'ete fait sur les Plecoptera
d'Amerique du Nord ont partie lie
avec  leur  taxonomie et leur mor-
phologie.    Malgre' le  travail  que
a ete fait,  les nymphes de plus de
durch Fische kann mit der Jahres-
zeit bedeutend schwanken und die
grossten Anderungen treten in Nu-
kliden von kurzer Lebensdauer auf,
welche mitdemFutter aufgenommen
werden.  Grosse  Unterschiede zwi-
schen Einzelproben erfordern fur
zuverlassige  Deutung der  Ergeb-
nisse   eine  grosse  Anzahl  von
Proben.
PHYSIOLOGISCHE   UBERLEGUN-
GEN  ZU STUDIEN DER WIRKUNG
VON  VERUNREINTGUNGEN   AUF
WASSERTIERE.  Paul O. Fromm.
p. 316.   Wenn  die Wirkungen von
Verunreinigungen des Wassers auf
im Wasser lebende Tiere  richtig
abgeschatzt werden sollen,   dann
mussen Versuche von langer Dauer
mit nicht akut tbdlichen Konzentra-
tionen der Giftstoffe ausgefuhrtwer-
den.   Spezifische physiologische
Kennzeichen  chemischer, morpho-
logischer Oder histopathologischer
Natur  werden  vorgeschlagen  und
Anwendungsbeispiele werden  gege-
ben.   Ausserdem wird eine  all-
gemeinere  Methode zur Abschatzung
der Wirkung  von Verunreinigungen
auf Wassertiere besprochen.  Diese
Methode  erfordert Messung des all-
gemeinen Stoffwechsels (Sauerstoff-
verbrauchs) von Versuchstierenund
fusst  auf der Annahme, dass jede
Biirde, welche  einem Tier von der
Umgebung  auferlegt wird, sich in
einer 'Anderung (Vermehrung oder
Verminderung) der normalen Stoff-
wechselrate zu erkennen gibt. Vor -
und Nachteile dieser zwei Methoden
des Studiums von Wasserverunreini-
gung werden besprochen.
UMWELTBEDINGUNGEN     DER
PLECOPTERA.   Arden R. Gaufin.
p. 105 .Wiewohl Plecoptera ("stone-
flies",  Fruhlingsfliegen)  eine  der
kleineren Insektenordnungen bilden,
sind sie trotzdem  eine der  wich-
tigsten  in  StrSmen  auftretenden
Gruppen.   In Bergfliissen sind sie
die  Hauptnahrungsquelle  fur Fo-
rellen.    Brink  berichtete,   dass
Fliisse in Schweden mit einer Kon-
zentration von gelSstem Sauerstoff
unter 40% Sa'ttigungkeine Fruhlings-
fliegen  hatten.   Da  sie klares gut
beliiftetes Wasser bevorzugen,  so
werden  sie in zunehmendem Grade
als Anzeiger fur  reines Wasser in
Studien  uber Wasserverunreinigung
wichtig.
   Praktisch alle bisherigen Arbei-
ten an  nordamerikanischen Fruh-
                                                       395

-------
been described. This is particularly
true of our western species.

   Research by Hynes, by Aubert,
and  by Brinck, in Europe, indicated
that European stoneflies differ per-
haps more in their ecology than they
do taxonomicallyor morphologically.
In view  of this  fact, detailed  in-
formation as to the habitat require-
ments and physiological differences
of the various species may be quite
essential to stonefly taxonomists if
they ever separate successfully  the
many yet unidentified forms.

   Most  of the ecological data that
have been published  concerning both
European and North American stone-
flies consist of general statements
as  to  habitat preferences.   Hynes
mentioned five major factors as con-
trolling the distribution of stoneflies
in England, namely, movement of the
water, altitude, substratum, drought,
and possibilities of colonization.
Brinck considered the following
factors as being most important in
determining the distribution of
Swedish  stoneflies: movement of the
water, substratum, temperature, the
amount of  certain gases and com-
pounds in the water, and the pres-
ence of food.

   The author has found  that such
factors as temperature,  water ve-
locity, bottom type,  chemical com-
position  of the water, and abundance
of food  are very important  in de-
termining the distribution of  stone-
flies in streams of the Inter mountain
Area.    In order to determine  the
environmental   requirements  of
stoneflies more precisely than can
be  done under  field   conditions,
studies  have  been conducted in
artificial streams in the laboratory
during the last  3 years.  The ob-
jectives  of these studies have been
to  determine  the  effects  of low
dissolved oxygen concentrations at
various  temperatures and stream
velocities  on  the gross activity of
stoneflies,  and  to  determine  the
minimum dissolved oxygen concen-
trations  at which exposure  for a
prolonged  period  of time can  be
endured without lethal effects.

   Optimal water temperatures for
the  species of stoneflies  tested to
date have been found to be between
50°  to 60 °F.  In this temperature
range  three  species of  stoneflies
were exposed to oxygen concen-
trations  as low as  3 ppm  for  24
hours with no mortality. Sensitivity
to low  dissolved oxygen  concen-
trations  increased rapidly with an
increase of temperature above 60°F.
50%  de  nos especes d'Amerique du
Nord n'ont pas etc decrites.  Ceci
est particulierement  vrai pour nos
espe'ces de 1'ouest.

   Les  recherches par  Hynes,
Aubert, et Brinck, en Europe, ont
indique  que  les  Plecoptera
europeennes  differentes  peut-e"tre
plus dans leur ecologie  qu'ils dif-
ferent taxonomiquement et morpho-
logiquement.  Vue ce fait, 1'infor-
mation  detaillee  comme  les con-
ditions d'habitat et les^ differences
physiologiques des especes variees,
peut  etre  tout a  fait essentiel au
Plecoptera  taxonomiste  si  ils ne
separent jamais les formes encore
non identifiees.

   La plupart des donnees ecologi-
ques  qui ont ete publie concernant
les Plecoptera europeennes etNord-
Americaine consiste en des rapports
gtneraux  comme  les preferences
d'habitat.    Hyne a mentionne  cinq
facteurs majeur controlant  la  dis-
tribution de  Plecoptera en Angle-
terre, ce  sont: la mouvement de
1'eau,  1'altitude, le substratum, la
secheresse,  et la  possibilite de
colonisation. Brinck a consider e les
facteurs suivants comme  etant plus
important  en determinant la  dis-
tribution de  Plecoptera  suedois le
mouvement de 1'eau, le substratum,
le temperature, la quantite de gaz
et de composants  dans 1'eau, et la
presence  de nourriture.  L'auteur
a trouve que des facteurs tels que
la temperature, la Vitesse de 1'eau,
le type  du  fond,  la composition
chimique de 1'eau, et  1'abondancede
la nourriture,  sonttres importants
pour  determiner la distribution de
Plecoptera  dans  les cours d'eau
occupant des regions non montag-
neuses.   Afin de  determiner les
conditions de milieu des Plecoptera
plus  precisement  qu'elles peuvent
e*tre donnees dans des- conditions de
terrain,  des etudes  ont  ete faites
en cours d'eau artificiel en labora-
toire durant  les  trois  dernieres
annees.

   L'objectif de  ces etudes a ete
de determiner  les effets  de basses
concentrations  d'oxygene  dissous a
des  temperatures  variees et de la
vitesse des cours d'eau sur la grosse
activite de Plecoptera et de deter-
miner le minimum de concentration
d'oxygene  dissous  a laquelle 1'ex-
position, pour une periode de temps
prolongee peut  etre  enduree  sans
effets lethals.

   Les temperatures de 1'eau pour
les Plecoptera essay es ont ete trouve
entre 50° et 70°F.  (10°  et^20°C.).
Dans ce domaine de temperature,
trois especes de Plecoptera furent
exposes   une concentration  d'oxy-
lingsfliegen besch'aftigten  sieh mit
ihrer Taxonomie und Morphologic.
Trotz all dieser Bem'iihungen  sind
die  Nymphen  von  uber  50% der
nordamerikanischen  Arten  noch
nicht beschrieben worden.   Dies
trifft besonders fur die im Westen
vorkommenden Arten zu.

   Studien von  Hynes,  von Aubert
und  von  Brink in Europa zeigten,
dass  die europaischen   Friihlings-
fliegen  sich von den  "stonef lies'
vielleicht mehr in ihrer Oekologie
als taxonomischodermorphologisch
unterscheiden. In Anbetracht dieser
Tatsache  konnen Arbeiten uber die
Anforderungen dieser  Insekten an
ihre Umweltund'uber physiologische
Unterschiede   der  verschiedenen
Arten fiir Forscher auf diesem Ge-
biet  sehr  wichtig sein, wenn sie die
vielen bisher  nicht identifizierten
Formen ordnen wollen.  Die meisten
veroffentlichten   Angaben   uber
europaische und nordamerikanische
Arten  sind allgemein  gehalten im
Bezug auf Umweltbedingungen.  Fiir
England gibt Haynes fiinf die Ver-
teilung beeinflussende Punkte: Was-
serbewegung,  Meereshohe, Boden-
schicht, DurreundMoglichkeitender
Kolonienbildung.    Brink  halt fur
schwedische Fruhlingsfliegen  die
folgenden Faktoren fur wichtig: Was-
serbewegung,  Bodenschicht,  Tem-
peratur, Gehalt des Wassers an ge-
wissen Gasen und Verbindungen und
Nahrung.

   Der  Vortragende hat gefunden,
dass  Temperatur,   Wasserge-
schwindigkeit,  Bodenschicht,   che-
mische Zusammensetzung des  Was-
sers  und Nahrungsfulle fiir  die
Bestimm'ang  der  Vert2ilung der
"stoneflies" in  Flussen  der sog.
Intermountain  Area  sehr   wichiig
sind.   Um die Umweltbedingungen
dieser Insekten  noch  klarer fest-
zulegen  als das an Ort und  Stelle
gemacht werden kann, wurden w'ah-
rend  der  vergangenen drei  Jahre
Versuche an kiinstlichenStromenim
Laboratorium  durchgeflihrt.    Sie
sollten den Einfluss niedriger Kon-
zentrationen an gel'ostem Sauerstoff
bei verschiedenen Temperatur en und
Wassergeschwindigkeiten  auf das
allgemeine Verhalten  der  "stone-
flies" zeigen  und  die  Mindestkon-
zentration an  gelostem Sauerstoff
bestimmen lassen, welche selbst in
langen Zeitraumen fUr die Insekten
nicht tbdlich ist.

   Besttemperatur des  Wassers fiir
die  "stonefly" Art, welche bisher
untersucht wurde, ist zwischen 50°
und 60° F. Bei dieser  Temperatur
war en fiir drei  Arten  'Bauer stoff-
konzentrationen von  nicht mehr als
3  mg/1.  fur 24 Stunden ertraglich.
Die Empfindlichkeit gegen niedrige
                                                        396

-------
                                        geneendessous de trois p.p.m. pour
                                        24 heures sans relever de mortalite.
                                        La sensibilit^ aux basses concen-
                                        trations  d'oxygene  s'est  accrue
                                        rapidement avec une accroissement
                                        de temperature au-dessus de 60°F.
                                        Konzentrationen angelostemSauer-
                                        stoff nimmt fiir Temperaturen uber
                                        60° F. sehr rasch zu.
 TOXIC WATERBLOOMS OF BLUE-
 GREEN ALGAE.  Paul R. Gorham.
 p. 37  .    The  unialgal  culture
 of colonies of blue-green algae iso-
 lated from toxic and non-toxic water-
 blooms has  provided new insights
 into the old problem of algal poison-
 ing.  Toxicity tests have been con-
 ducted on 24 blooms representing 4
 dominant   species  and 52 strains
 representing 10 species. Toxic and
 non-toxic  strains  of Microcystis
 aeruginosa Kutz.  emend.  Elenkin
 and Anabaena flos-aquae  (Lyngb.)
 de  Breb.  have  been isolated from
 toxic and non-toxic blooms. So far,
 only  non-toxic  strains have been
 isolated of three other species sus-
 pected of  toxicity: Aphanizomenon
flos-aquae  (L.) Ralfs., Gloetrichia
 echinulata  (J. E. Smith) P. Richter,
 and Coelosphaerium Kutzingianum
 Nageli.   Bacteria associated with
 waterblooms  have  been   found  to
 produce  toxic  factors, but  these
 appear  to  play a secondary role.

    Toxic Microcystis strains pro-
 duce afast-deathfactor (FDF),which
 kills laboratory animals  and live-
 stock when administered orally.
 Toxic  Anabaena strains produce a
 very-fast-death factor   (VFDF),
 which is also active when adminis-
 tered orally.  Microcystis FDF  is
 an  endotoxin  whose  production  is
 physiologically  as well as geneti-
 cally controlled.  It is ordinarily
 released during senescence or de-
 composition of the cells. It has been
 isolated and  identified as  one of a
 group of five rather  similar  poly-
 peptides.   Microcystis  FDF has an
 LD50 (IP,  mice) of  0.5 milligrams
 per  kilogram; freeze-dried Micro -
 cystis  cells  have an LDlOO (oral,
 various animals) of 1 to 2 grams per
 kilogram.  Anabaena VFDF may  be
 an  exotoxin.  It has some properties
 that resemble those of Microcystis
 FDF.

    The development of a toxi c water -
 bloom depends on the favorable in-
 teraction  of  at least six variables:
 (1)  presence  and  dominance of  a
 toxic strain of alga; (2)  size and
 composition  of the associated bac-
 terial flora;  (3) conditions required
 for algal toxin production; (4) con-
 ditions required for aggregating
 large masses of algae near shore;
 (5)  conditions required for the re-
 lease of toxins without undue dilution
 or  destruction;  and  (6) ingestion  of
TOXICITE DBS FLORAISONS DES
ALGUES  BLEUES-VERTES.  Paul
R. Gorham.  p. 37 . Des cultures
uniformes de colonies  d'algues
bleues-vertes prelevees de florai-
sons  toxiques et  non toxiques ont
eclairci  le  vieux  probleme d'em-
poisonnement par les algues.   On
a  fait  des  tests de  toxicite  sur
24 floraisons representant 4 especes
predominantes et  sur 52  cultures
representant 10 especes.  A partir
de floraisons toxiques et non toxiques
on a pu isoler des  cultures toxiques
et  non  toxiques  de  Microcystis
aeruginosa Kutz. emend, Elenkin et
Anabaena flos-aquae  (Lyngb.)  de
Breb.  Jusqu'a date,  on a pu isoler
seulement des cultures non toxi-
ques  de trois especes qu'on croit
§tre  toxiques;  ce sont:   Aphani-
zomenon flos-aquae    (L.)  Ralfs.,
Gloeotrichia echinulata (J. E. Smith)
P.  Richter,  et  Coelosphaerium
Kutzingianum Nageli. Lesbacteries
associees aux  fluoraisons peuvent
produire des elements toxiques,
maisceux-ci semblentjouer un role
secondaire.

   ^,.s cultures toxiques de Micro-
cystis ont un element de mortrapide
(•* FDF^) quiamene la  mortd^nimaux
de laboratoire et de ferme lorsque
administre par voie  buccale.   Les
cultures toxiques  de Anabaena ont
aussi  un element de  mort  tres
rapide (^VFDF^) lorsque administr?
par voie buccale.  L'element^FDF^
de Microcystis est une  endotoxine
dont  la  production  est  contrSlee
aussi bien au point  de vue physio-
logique que genetique. D'ordinaire
cette  endotoxine est liberee durant
le vieillissement ou la decomposition
des  cellules.  On a pu  1'isoler et
1'identifier  comme  faisant partie
d'un  groupe de   cinq polypeptides
similaires.   L'element ^FDF^de
Microcystis aun LD50 (* IP'*, souris)
de 0.5 milligrammes par kilogram-
me.    Les cellules de Microcystis
sechees-congelees ont  un LDlOO
(par  voie buccale,   differents
animaux)  de 1 a  2  grammes  per
kilogramme.   L'element ^VFDF^-
d 'Anabaena peut etre une exotoxine.
Certaines de  ces  proprietes  res-
semblent  a celles de Microcystis.

   Le developpementd'unefloraison
toxique depend d'au moins six fact-
eurs et de leurs actions combiners,
elles  sont enumerees ci-dessous:
(1) la presence et la predominance
GIFTIGE  WASSERBLtJTE  BLAU -
GRUNER ALGEN. Paul R. Gorham.
p. 37 .  Reinkulturen von Kolonien
blau  -  griiner Algen  aus giftigen
und  ungiftigen Wasserbliiten haben
neue  Einblicke in das alte Problem
von  Vergiftungen durch Algen er-
laubt.  Giftigkeitsversuche wurden
an 24 Wasserbliiten, welche 4 vor-
herrschende  Arten  und 52 St'amnie
von 10  Arten darstellten, gemacht.
Giftige  und ungiftige Stamme  von
Microcystis  aeruginosa  Kutzing
emend. Elenkin und Anabaena flo s -
aquae (Lyngbye) de Brebisson wur-
den von giftigen und ungiftigen Blii-
ten isoliert.    Bisher  wurden  von
drei anderen Arten, welche giftig-
keitverdachtig waren, namlich Ap-
hanizomenon flos -  aquae (L.) Ralfs,
Gloeotrichia echinulata (J. E, Smith
und Sowerby) P.  Richter und Coel-
osphaerium Kutzingianum  Nageli,
nur ungiftige Stamme isoliert.  Zu-
sammen mit  Wasserbluten  vor-
kommende  Bakterien konnen giftige
Stoffe erzeugen, doch scheinen diese
nur  eine untergeordnete  Rolle  zu
spielen.

   Giftige Microcystis Stamme er-
zeugen einen rasch todlich wirkenden
Faktor  (FDF), der  Laboratoriums-
tiere und landwirtschaftliche  Nutz-
tiere   bei per  os Verabreichung
totet.   Giftige  Anabaena  Stamme
bringen einen ebenfalls per os sehr
rasch  todlich  wirkenden  Faktor
(VFDF) hervor. Microcystics FDF
ist ein Endotoxin, dessenErzeugung
physiologisch und  genetisch  kon-
trolliert ist.  Es wird gewohnlich
wahrend des  Alterns  Oder   der
Zersetzung der Zellen abgesondert.
Es wurde isoliert und als eines von
5 einander ziemlich ahnlichen Poly-
peptiden erkannt.  Micro cystis FDF
has  a  LDso (IP> Mause)  von 0,5
rng/kg;  durch   Gefriertrocknung
erhaltene   Microcystis  -   Zellen
haben LDjgo (Peros, verschiedene
Tiere) von 1 bis 2 Gramm per Kilo-
gramm.  Anabaena  VFDF ist viel-
leicht ein Exotoxin. In seinen Ei-
genschaften gleicht  es dem Micro-
cystis VFDF.

   Die  Entwicklung einer gittigen
Wasserblilte  hangt vom  giinstigen
Zusammenwirken von  mindestens
sechs VerSnderlichen  ab : 1.  Ge-
genwart und Vorherrschen eines gif-
tigen Stammes von Algen, 2. Gr'osse
und Zusammensetzung der die Algen
begleitenden  Bakterienflora, 3. Be-
                                                       397

-------
 sufficient  amounts  of  toxin at the
 right time by susceptible species of
 animals.

    The effects of toxic waterblooms
 on  various  other  organisms  are
 discussed.
d'une  culture toxique d'algue,  (2)
le volume et la  composition de  la
Uore bacterienne associee, (3) les
conditions requises  pour la pro-
duction de toxines par les algues,
(4)  les  conditions  requises pour
rassembler de larges   masses
d'algues  pres du rivage,  (5) les
conditions requises pour liberer des
toxines sans trop les diluer ou les
detruire,  (6)  1'ingestion de quantites
suffisantes de toxine, aubon moment,
par  certains animaux susceptibles.

   On discute aussi des effets des
floraisons toxiques  sur  d'autres
organismes varies.
dingungen nbtig fur Toxinerzeugung
durch  die  Algen, 4. Gunstige Be-
dingungen  ftir   die  Ansammlung
grosser  Algenmassen   nahe  der
Kiiste,  5.   Bedingungen notig zur
Abgabe  des  Toxins ohne  zu viel
Verdunnung Oder Zerstorung und 6.
Rechtzeitige Einnahme genligender
Toxinmengen  durch  eine daftir em-
pfindliche Tiergattung.

   Die Wirkungen giftiger Wasser-
bliiten  auf  verschiedene   andere
Organismen werden besprochen.
 SOME ENVIRONMENTAL EFFECTS
 OF COAL AND GOLD MINING ON
 THE  AQUATIC BIOTA.   A. D.
 Harrison.    p. 270 .  The effects
 of  coal  and gold mining  are  dis-
 cussed  in the light  of  experience
 in  South  Africa.   There  are two
 main effects on streams from both
 types of mining: silting and pollution
 by acid sulphates. The latter is the
 more serious. Acid sulphates, re-
 sulting  from bacterial  action or
 pyrite rocks and ores, contaminate
 effluents  from  mines and  mine
 dumps, which frequently have  a pH
 as  low as 2.3 and contain dissolved
 sulphates of the  order of 2000 ppm
 or  more.  In polluted streams and
 swamps  when the pH is constantly
 below 5,  characteristic associations
 of plants and animals appear. These
 are discussed. After neutralization,
 high  sulphate values of  up to  1000
 ppm  appear  to have  little effect on
 the normal biota.  Where pollution
 is periodic and pH values fluctuate
 from very  acid  to alkaline,  the
 biota is  greatly impoverished and
 characteristic associations are not
 found.
QUELQUES,   CONDITIONS   DU
MILIEU DETERMINERS  PAR  LES
MINES DE CHARBONET D'OR ET
LEUR  EFFET   SUR   LA  VIE
AQUATIQUE. A. D. Harrison, p.270.
On a etudie  ici les  effets de 1'ex-
ploitation des mines de charbon et
d'or  en se  servant  d'experiences
en Afrique du Sud.   Ces exploita-
tions minieres produisent deux effets
principaux sur les cours d'eau, ce
sont  1'envasement  et  la pollution
par les sulfates acides. Le dernier
effet  est plus serieux.  Les  sul-
fates acides, provenant de 1'action
des bacteries sur lesrochespyrite-
uses  et sur  le mineral contaminent
les  rivieres pres  des  mines et
pres  des depots  de mineral.  Ces
rivieres ont parfois  un pH tres bas,
de 1'ordre de 2.3 et  contiennent des
sulfates dissous  dans Pordre  de
2,000 ppm  ouplus. Dans les rivieres
et les  marais pollues, lorsque le
pH  se maintient  constamment  en
bas de 5, il se forme des associations
caractferistiques   de  plantes et
d'aoimaux  qu'on discute ici.  Apres
la neutralisation, les concentrations
elevees en  sulfate,  jusqu'a 1,000
ppm semblent avoir  bien peu d'effet
sur  le contenu biologique normal.
Qaand la pollution est periodique et
que  le  pH  subit des fluctuations
indiquant alternativement un milieu
tres  acide  et alcalin, le  contenu
biologique  est fortement appauvri
et on  ne trouve pas d'associations
caract£ristiques.
 EINIGE   UMGEBUNGSEINFLUSSE
 VON KOHLEN  - UNDGOLDBERG-
 ARBEIT   AUF  DAS  LEBEN  IM
 WASSER.  Arthur D. Harrison. P.
 P- 270.  Im Lichte von Erfahrungen
 in  Sudafrika werden die Einflusse
 von Kohlen  -  und  Goldbergarbeit
 besprochen.  In beiden Fallen sind
 Verschlickung  und  Verschmutzung
 durch  saure Sulfate die  Hauptein-
 flusse und jener durch Sulfate muss
 ernster genommen werden.  Saure
 Sulfate  entstehen durch Bakterien-
 wirkung  auf  Schwefelkiesgesteine
 und -  erze; sie verunreinigen die
 Abwasser  von  Bergwerken  und
 Halden,  welche dann oft eine pH
 Stufe von  2,  3 haben  und gelbste
 Sulfate  in der  Grb'ssenordnung von
 2  g/1   (= 2 000 parts per million)
 Oder noch mehr enthalten. In ver-
 unreinigten Stromen und Sumpfen
 treten,  wenn die pH Stufe dauernd
 unter  5,0 liegt, charakteristische
 Verbande von Tieren und Pflanzen
 auf, welche besprochen   werden.
 Nach Neutralisierung scheinen hohe
 Sulfatwerte bis  zu  1 g/1  ( = 1 000
 parts per  million)  wenig Wirkung
 auf die  normale Lebewelt zu  haben.
 Wo  die  Verunreinigungen in re-
 gelmassigen Zeitabstanden auftreten
und diepHWerte sichzwischen stark
 sauer und  stark alkalisch bewegen,
da  verarmen  die   Gegenden sehr
 an  Lebewesen  und  die charakteri-
 stischen  Verbande werden  nicht
 mehr gefunden.
CONTROL  OF  FISH PARASITES.
Glenn  L. Hoffman,  p. 283.  Fish
infected  with  fungi, protozoa, hel-
minths, and parasitic copepods may
be unsuitable for experimental use,
including  the  bioassay  of polluted
water. Methods of prophylaxis, and
treatment if known,  are discussed.

   Saprolegnia  and related fungi can
be  controlled with malachite green.
CONTROLS  DES PARASITES DU
POISSON. Glenn  L. Hoffman.p. 283.
Le  poisson  infect!  par  fungi,
protozoa,   helminths et  copepods
parasitiques n'est pas apte a 1'utilite
experimental, incluant les essais
d'eau polluee.   Les methodes de
prophylaxie et de traitement connu,
sont decrites.  Saprolegnia et fungi
peuventetre controle's par malachite
verte.    La  plupart de  protozoa
KONTROLLE  VON FISCHPARASI-
TEN.  Glenn  L. Hoffman,  p. 283.
Fische, welche mit Pilzen,  Urtier-
chen, Wurmern und   parasitischen
Krustentieren infiziert sind, konnen
fur Versuchszwecke, einschliesslich
von Bioversuchen an verunreinigtem
Wasser,  ungeeignet sein.  Vorbeu-
gungsmethoden und, wenn  bekannt,
Behandlungsverfahren werden be-
sprochen.
                                                       398

-------
 Most external protozoa  can be re-
 moved  with  formalin,  potassium
 permanganate, etc.  Hexamita, an
 intestinal parasite, can be eradi-
 cated with carbarsone, calomel, etc.

   Intestinal helminths can be re-
 moved with  di-n-butyl-tin oxide, but
 there is no known chemotherapy for
 fish tissue  parasites.  Leeches and
 parasitic  copepods can  sometimes
 be  removed with insecticides, and
 predaciousbeetle larvae can be killed
 with kerosene on the pond.

   Prophylaxis  is  probably more
 important than treatment.  This in-
 volves  selection of  parasite-free
 stock, control of intermediate hosts,
 and external prophylactic treatment
 of  fish  at  time of  collection or
 transfer.
 externes  peuvent §tre extrait par
 formaline, potassium permanganate
 etc.  L'Hexamita, un parasite in-
 testinal peut itre deracine par car-
 barsone, calomel, etc.

   Les helminths  intestinales
 peuvent  etre extraites avec di-n-
 butyl-oxide  d'etain mais  rien n'est
 connu pour les parasites des tissues
 de  poisson.    Les sangsues et les
 cop£podes parasitiques peuvent
 parfois ^tre  extraits par des in-
 secticides et les larves de coleoptere
 peuvent  Stre tue'es par le keVos&ne
 sur  les etangs. La prophylaxie est
 probablement plus importante que
 le traitement.  Ceci implique une
 selection de parasites  libres,  un
 controle de traitement prophylatique
 externe  du  poisson au moment du
 ressemblement ou du transfert.
   Saprolegnia und verwandte Pilze
kbnnen  mit Malachitgrun im Zaume
gehalten werden.  Die meisten Ur-
tierchen an Oberflachen kormen mit
Formalin, Kaliumpermanganat usw.
entfernt werden.    Hexamita, ein
Eingeweideparasit, ist mit Carbar-
sone, Kalomel usw. ausrottbar.

   Eingeweidewiirmer  kb'nnen  mit
Di-n-butylzinnoxyd entfernt werden,
gegen  Fischgewebeparasiten   ist
jedoch  bisher keine  chemothera-
peutische Methodebekannt. Blutegel
und parasitische  Krustentiere sind
manchmal mit Insektenvertilgungs-
mitteln entfernbar  und Kaferlarven
kb'nnen durch eine SchichtvonKero-
sin auf der  Oberflache von Teichen
getotet werden.

   Vorbeugung ist wahrscheinlich
wichtiger als Behandlungsmethoden.
Das  bedeutet  Wahl von parasiten-
freiem  Fischbesatz, Kontrolle von
Zwischenwirten  und   vorbeugende
Oberflachenbehandlung der Fische
beim Sammeln und beim Uberfiihren
von einer Stelle zur andern.
 HOW  SHOULD  AGRICULTURAL
 POLLUTANTS BE CONTROLLED.
 C.  H. Hoffmann,   p. 253.  There
 is no question as to the importance
 and necessity of agricultural chemi-
 cals  in  the  prod-lotion and con-
 servation of food,  feed, and fiber,
 and  in  protecting plants, animals,
 and man from serious diseases. With
 the increased use of these chemicals,
 however,  there  is  great  concern
 about their  persistence in the soil,
 particularly as potential water pol-
 lutants.  Recent  studies regarding
 agri cultural chemi cals as water pol-
 lutants  are reviewed in  order to
 indicate the magnitude of the prob-
 lem.  There are several approaches
 to the control of agricultural pol-
 lutants, including the enactment of
 federal and  state laws  and regu-
 lations permitting the use  of agri-
 cultural chemicals under  specified
 conditions; supervised pest control
 programs in which trained and re-
 sponsible  operators use  toxic
 materials;  and the establishment of
 federal or state pest control review
 boards, representing  different
 agencies and interests to assure
that  widespread  control programs
 are conducted in the public interest.
 The importance of educational activ-
ities and good public relations cannot
be  overemphasized   in connection
with the general  safe use of agri-
 cultural  chemicals  to avoid  un-
necessary pollution.  The interest of
various national societies and other
groups representing  different dis-
ciplines concerned with various
CONTROLE  DES  PRODUITS
AGRICOLES  POLLUANTS.   C. H.
Hoffmann,   p. 253 .   11 n'est pas
question de revenir sur 1'importance
et la necessite des produits chim-
iques agricoles dans  la production
et la conservation des aliments et
des fouo. rages et dans la protection
des plantes, des  animaux et m3me
de  1'homme contre  des  maladies
graves.  Cependant,  avec 1'emploi
toujours plus grand de ces produits,
il existe un grave probleme ausujet
de  leur persistance  dans  le  sol,
particulierement  vis  a vis d'une
pollution possible des eaux.  Des
etudes recentes concernant les pro-
duits chimiques agricoles en tant que
substances polluantes sont passees
en revue afin de montrer 1'ampleur
du probleme.  II existe plusieurs
moyens d'aborder  le controle de
substances polluantes comprenant:
la promulgation de lois federates et
d'etat  et des reglementations
autorisant 1'emploi des produits
chimiques agricoles dans des con-
ditions bien determinees;  des pro-
grammes de destruction dirigeesou
des operateurs instruits et respon-
sables  emploient  les  produits
toxiques; et 1'etablissement de
conseils federaux au  d'etat pour la
destruction  des  nuisibles  groupant
les  representants  des  differents
interets  pour  s'assurer  que  les
campagnes  de  pulverisation  sont
menees en vue de 1'interet public.
L'importance  des  activites d'en-
seignement  et de bonnes vulgeri-
sations  ne peut etre trop soulignee
WIE     SOLLTEN    LANDWIRT-
SCHAFTLICHE..  WASSERVERUN-
REINIGUNGEN UBERWACHT WER-
DEN?  Clarence H. Hoffman, p. 253.
Die  Wichtigkeit und Notwendigkeit
von landwirtschaftlichen Chemika-
lien in der Erzeugung und Erhaltung
von  Nahrungs  - und  Futtermitteln
und von FaserstoffenundzumSchutz
von Pflanzen, Tieren und Menschen
gegen  ernste  Erkrankungen steht
ausser  Zweifel.  Mit zunehmender
Anwendung   dieser    Chemikalien
wachst indessen die Besorgnis uber
ihre Beharrung im Boden, besonders
als mogliche Verunreinigungen des
Wassers. NeuereStudienaufdiesem
Gebiet werden taesprochen urn die
Grosse  des  Problems darzulegen.
Man kann die Uberwachung dieser
landwirtschaftlichen    Verunreini-
gungen  auf   verschiedenen  Wegen
angehen, z.  B. durch Bundes - und
Staatsregelungen und Gesetze, wel-
che die Anwendung landwirtschaft-
licher Chemikalien unter bestimmten
Bedingungen gestatten, durchbeauf-
sichtigte  Ungezieferkontrollmass-
nahmen, in welchen geschultes und
verantwortliches   Personal  diese
giftigen  Staffe anwendet und durch
Errichtung   von   Bundes   - Oder
Staatsausschiissen zur Uberwachung
der Ungezieferkontrolle, in welchen
die  verschiedenen Behbrden  und
Interessenten vertreten sind, damit
Gewahr dafiir gegeben ist, dass die
umfassenden  Kontrollmassnahmen
im offentlichen Interesse  liegen.
Die Wichtigkeit erzieherischer  Ta-
tigkeit  und  guter Beziehungen zur
                                                       399

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aspects of water pollution which hold
seminars,  symposia,  and confer-
ences to consider various problems
is not only stimulating to research
and  control workers but also the
publicity associated with such meet-
ings enables the public to become
better informed.   Moreover, some
organizations  help finance studies
on special problems or seek support
for research needed to answer urgent
problems.   The  role  of  research
in the discovery of new pest control
materials  that  are less toxic to
other organisms  and, therefore, of
less consequence as water pollutants
is emphasized.   In addition, more
research is needed on nonchemical
methods of pest control, which would
obviate some water pollution prob-
lems.
en liaison  avec un emploi rationnel
des  produits  chimiques  agricoles
pour eviter une pollution superflue.
II est  interessant  que differentes
societes nationales et des groupes
representant  des disciplines  dif-
ferentes touchant les divers aspects
de la  pollution des eaux, tiennent
des seminaires,  symposia ou con-
ferences pour etudier ces problemes
car non seulement  ils stimulent ia
recherche  et  ceux  qui  contr&lent
les operations,  mais la publicite
faite autour de ces reunions permet
de mieux  informer le public.   De
plus quelques  organisations  aident
financierement des etudes sur des
problemes parti cullers ou cherchent
une aide  pour resoudre  des pro-
blems  urgents.    Le role  de  la
recherche  dans  la  decouverte de
nouveaux pesticides moins danger-
eux  pour  les  autres  organismes,
done moins susceptibles de polluer,
est soulignee.    De  plus,  il  est
necessaire de developper les re-
cherches  sur  les methodes de con-
trSle non chimiques, ce quipourrait
prevenir  d'autres  problemes  de
pollution.
Offentlichkeit kann im  Zusammen-
hang  mit der allgemeinen sicheren
Anwendung     landwirtschaftlicher
Chemikalien  zur  Vermeidung un-
notiger Verunreinigung nicht genug
betont werden.  Verschiedene na-
tionale Gesellschaften und Interes-
sengruppen    sind durch  die Viel-
seitigkeit des Problems der Wasser-
verunreinigung beunruhigt und halten
Seminare, Symposien und Konferen-
zen zur  Besprechung  der auftre-
tenden Fragen; solche Tatigkeit 1st
einerseits anregend  fur  Forscher
und Kontrollpersonal, andererseits
aber  auch  von  ganz  allgemeiner
Wichtigkeit,  well die  Werbekraft
solcher Zusammenkunfte der Offen-
tlichkeit eine bessere Sachkenntnis
vermittelt.  Ausserdem unterhalten
einige   Vereinigungen Oder Kor-
perschaften das Studium von Sender-
fragen durch Geldzuwendungen oder
werben fur  geldliche Unterstutzung
von Forschungsarbeiten liber drin-
gende Fragen.  Die Rolle der For-
schung  in  der  Entdeckung  neuer
Ungeziefervertilgungsmittel von ge-
r ingerer Giftigkeit gegen erwunschte
Organismen und deshalb geringerer
Gef ahr lichkeit  als Wasser-
verunreinigungen  wird   hervor-
gehoben.  Mehr Forscherarbeit  an
nichtchemischen Verfahren der
Ungezieferkontrolle   ist notig; da-
durch konnten zum mindesten einige
der    Wasserverunreinigungspro-
bleme beseitigt werden.
RELATIONS  OF  PLANKTONIC
CRUSTACEA TO DIFFERENT AS-
PECTS OF POLLUTION. J.Hrbacek.
p. 53  .   The following  are dis-
cussed:   occurrence of  common
planktonic species of Crustacea in
different  saprobiological degrees;
subjectivity  in estimating the de-
pendence  of  planktonic species of
Crustacea on the extent of saprobity
and  efforts  for development of  a
more objective approach; and re-
lations of  different groups of plank-
tonic Crustacea to various primary
or secondary  consequences of pol-
lution :
1. Abiotic — pH,  oxygen,  hydrogen
   sulphide, and  toxic substances.
2. Biotic — the concentration of food
   particles;  the influence of pre-
   dation.

   There  are relatively  large dif-
ferences  between morphologically
closely-related species of the genus
Daphnia in the ability  to survive
under  different nutritional condi-
tions.  In ponds with good fishstock,
observations illustrate that the abun-
dance  of  the  predominant species
of planktonic Crustacea is reduced.
A new interpretation of the possible
causes of changes in species  com-
RELATIONS  ENTRE  LES  CRUST-
ACES  PLANCTONIQUES  ET DIF-
FERENTS ASPECTS DE LA POL-
LUTION.    J.  Hrbacek.   p. 53  .
Les  sujets suivants sont  discutes:
presence d'especes communes  de
crustaces planctoniques  dans  les
differentes zones de saprobies; sub-
jectivite  dans  1'estimation  de la
dependance des especes de crustaces
planctoniques vis a vis de 1'evalu-
ation des saprobies, et efforts pour
developper des methodes plus objec-
tives; relations de differents groupes
de  crustaces planctoniques avec
diverses consequences primaires
ou secondaires de pollution:
1. abiotique-pHoxygene,hydrogene
   sulfure  et substances  toxiques
2. biotique -  concentration des par-
   ticules nutritives,  influence  des
   predateurs.

   II y a relativement beaucoup de
difference entre  des  especes tres
p r o c h e s  morphologiquement  du
genre  Daphnia  en  ci  qui  concerne
leur possibilite de  survie dans des
conditions de nutrition differente.
Dans des etangs riches enpoissons,
des observations  montrent  que
1'abondance des especes dominantes
est reduite.   L'auteur donne  une

              400
 DIE  BEZIEHUNGEN    ZW1SCHEN
 PLANKTONKRUSTAZEEN    UND
 VERSCHIEDENEN   VERUNREINI-
 GUNGSFRAGEN. Jaroslav Hrbacek.
 p. 53 .  Folgende Probleme werden
 besprochen:  das Vorkommen  ge-
wohnlicher Planktonarten von Krusta-
 zaen in verschiedenen saprobiolo-
 gischen  Graden; die   personliche
 Gleichung  in  der Beurteilung der
 Abhangigkeit der Planktonarten der
 Krustazeen vom  Saprobiensystem
 und die Bemuhungen  um die  Ent-
 wicklung  einer  sachlichen Bewer-
 tung; und  schliesslich die  Bezie-
 hungen  der verschiedenen Gruppen
 von Planktonkrustazeen zu weiteren
 hauptsachlichen oder untergeordne-
 ten  Folgen  der  Verunreinigung,
 namlich 1. abiotisch - pH, Sauer-
 stoff, Schwefelwasserstoff und Gift-
 stoffe 2. biotisch -  Nahrungskon-
 zentration,  Einfluss von Predation

   Morphologisch nahe verwandte
 Arten der Gattung Daphnia unter-
 scheiden sich betrachtlich in ihrer
 Fahigkeit verschiedene Erriahrungs-
 bedingungen  zu  uberleben.     In
 Weihern mit gutem Fischbesatz ist
 die Haufigkeit der vorherrschenden
 Art von Planktonkrustazeen herab-
 gesetzt.  Eine  neue  ErkTarung der

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position of zooplankton in polluted
lakes and reservoirs is given.

   A more complete knowledge of
physiological differences of species
is needed for understanding ecolo-
gical effects of pollution on different
species of planktonic Crustacea and
for utilizing these species as biolo-
gical  indicators for  water  purity
control purposes.
 nouvelle  interpretation  des  causes
 possibles  de  changement dans la
 composition des  especes de zoo-
 plancton dans les lacs et reservoirs
 pollues.

    Une connaissance plus complete
 des differences physiologiques  des
 especes est necessaire  pour com-
 prendre les influences ecologiques
 des  pollutions sur  les crustaces
 planctoniques  et  pour utilizer  ces
 especes comme indicateursbiologi-
 ques dans  les controles de  qualite
 des eaux.
 mbglichen Ursachen der 'Anderung
 in  der Artenzusammensetzung  des
 Zooplankton  in  verunreinigten Seen
 und Stauseen wird gegeben.

    Mehr  Kenntnis  der  physiolo-
 gischen Unterschiede der Arten ist
 zum Verstandnis der okologischen
 Wirkungen von  Verunreinigung  auf
 verschiedene  Arten  von Plankton-
 krustazeen  und  zur   Anwendung
 dieser  Arten als biologische An-
 zeiger  fur Wasserreinheit  notig.
WATER QUALITY CRITERIA FOR
FISH LIFE.  Marcel Huet.  p. 160.
For a particular habitat to be suit-
able  for fish, it is  necessary  that
the fish should be able to live and
develop there.  This means that the
environmental  factors  for respi-
ration,  feeding,  and reproduction
should be suitable.  Environmental
requirements   vary  considerably
from one kind  of fish  to another.
Within various types of water, the
following  distinctions should be
made:  salmonid waters,  mixed
waters, and cyprinid waters.

   Reasonably precise criteria can
only  be  given for certain factors:
temperature, dissolved  oxygen, and
pH.   Care must be  taken to avoid
confusing the  extremes for these
factors and the  optimum value for
the same factor. These details are
discussed in the text.   Other en-
vironmental factors  are  also  dis-
cussed.
CRITERES DE QUALITE DE L'EAU
EN RAPPORT AVEC LADUREEDE
VIE DU POISSON.   Marcel Huet.
p. 160 .  Pour qu'un habitat par-
ticulier  soit  convenable  pour  le
poisson, il  est  necessaire que  le
poisson  puisse  se  developper  et
vivre dans ce  milieu.  Ceciimplique
que lesfacteurs environnants pour la
respiration, 1'alimentation et la re-
production soit  convenables.   Les
conditions  requises  varient  con-
siderablement d'une   sorte  & une
autre. Entre les types varies d'eau,
les distinctions suivantes doivent
tstre faites:  eaux^tsalmonides^eaux
melangees, et eaux cyprinides.

   Les criteres precis peuvent
seulement £tre donne's  raisonnable-
ment  pour  certains facteurs: tem-
p£rature, oxygene dissous, et pH.
Des precautions doivent §tre prises
pour  'feviter la  confusion  des  ex-
tremes de ces facteurs et la valeur
optimum pour le m@mefacteur. Ces
details  sont disrates  dans le texte.
D'autres facteurs environnants  sont
aussi discutes.
 KENNZEICHEN DERWASSERGUTE
 GEGENUBER  FISCHEN.   Marcel
 Huet.  p. 160  .  Die Eigenschaften
 der   Umgebung,  welche  fur  das
 Leben und  Gedeihen  von  Fischen,
 fur deren Atmung, Stoffwechsel und
 Fortpflanzung notwendig sind, wech-
 seln   mit  der Gattung der Fische.
 Innerhalb  verschiedener  Wasser-
 typen  sollten die folgenden  Unter-
 scheidungen gemacht  werden:  sal-
 monide,   gernischte  und  cyprinide
 Wasser.

   Bestimmte   Kennziffern konnen
 nur  fur  einige  Eigenschaften wie
 Temperatur, gelosten Sauerstoff und
 pH  gegeben werden.  Hochst und
 Mindestwerte  fur  diese Faktoren
 durfen nicht mit dern Best'vert  ver-
 wechselt  werden.   Diese  Einzel-
 heiten und andere Eigenschaften der
 Umgebung werden im Text bespro-
 chen.
BACTERIA-PROTOZOA    INTER-
ACTIONS IN PURIFYING WATER.
S.  H.  Hutner.   p. 45  .   Unless
insecticides, plant  growth regula-
tors, detergents, and other products
of the  synthetic organic chemicals
industry  can  be  microbially  de-
graded, they may accumulate in soils
and contaminate water  supplies.  To
the author's knowledge a realistic"
laboratory  test to predict the sus-
ceptibility of synthetics is not avail-
able.    The  problem  can  be  put
operationally as: What is the smal-
lest, quickest developing laboratory
microcosm that reflects the macro-
cosm represented by, say, a sewage
lagoon? Recent findings that certain
photosynthetic    particle-ingesting
flagellates  are ubiquitous in fresh
waters, soils,  and  the ocean, em-
phasize that conventional dark en-
richments  are inadequate; enrich-
INTERACTION  DES  BACTERIE-
PROTOZOAIRES.    S.  H. Hutner.
p. 45 . Excepte que les insecticides,
les auxines,  les detergents,  et  les
autres produits organiques de 1'in-
dustrie chimique  peuvent  etre de-
grades  au niveau  du microbe,  ils
peuvent s'accumuler dans  le sol et
contaminer 1'alimentation!  d'eau. A
la  connaissance  de  1'auteur,  un
bon test de laboratoire pour predire
la suceptibilite'relativementaux syn-
thetique n'est pas disponible.

   Le probleme peut etre mis sous
la forme :<
-------
ment cultures with test substrates
might well be conducted under mixed
incandescent lamps (to  encourage
photosynthetic bacteria) and fluore-
scent lamps.  A related problem is
the degradability of the carcinogenic
hydrocarbons; this in turn is bound
up with the question of how the body
detoxifies unnatural compounds and
which protozoa are the best indices
of toxicity to higher animals.
sols et les  oceans et demontrent
que les enrichements conventionnel
au noir ne sont pas adequates.  La
culture d'enrichment  avec test de
reaction peut bien etre conduit sous
lampe   incandescente  (enfin d'en-
courager  la  bacterie  photosynthe-
tique) etflourescentemelangees. Un
probldme  relate  est la degradation
de 1'hydrocarbure canc'erigene; ceci
est en  relation avec la maniere ou
le corps  detqxifie  les composants
non naturel et que les protozoaires
sont le meilleur  indice de toxiquite
aux  animaux  d'especes plus com-
pletes.
keitsnah  wiedergeben?    Neuere
Entdeckungen iiber die weite Ver-
breitung  gewisser    photosynthe-
tischer  Geisseltierchen, welche
feste Teilchen als Nahrung aufneh-
men, in Gewassern, Boden  undim
Meere  betonen, dass  die ubliehen
Anreicherungen im  Dunklen unzu-
reichend  sind;  Anreicherungskul-
turen mit Versuchssubstraten kon-
nen  sehr wohl unter    Mischlicht
(Gluhlampen  zur  Forderung  des
Wachstums   photosynthetischer
Bakterien und Leuchtrohren) ausge-
fuhrt werden. Bin verwandtes Pro-
blem  ist   die   Abbaumoglichkeit
krebsverursachender   Kohlenwas-
serstoffe; diese Frage  wiederumist
mit  der anderen, wie der KSrper
Fremdstoffe entgiftet   und welche
Protozoen sich am besten als An-
zeiger  von  Giftigkeit  fur hohere
Tiere eignen, eng verbunden.
THE  SIGNIFICANCE  OF  MACRO-
INVERTEBRATES IN THE STUDY
OF  MILD  RIVER  POLLUTION.
H.  B. N.  Hynes.    p. 235 .  As
biological indicators of pollution, at
least initially, small organisms are
easier and more satisfactory to work
with than fish. A micro-invertebrate
analysis tells one if the situation is
worth investigating further.  Since
such a survey  is based on no hard
and fast system, it is flexible and
allows the investigator to look afresh
at each problem and to interpret the
data in the light of prevailing cir-
cumstances.  If the survey reveals
little change  in the  invertebrate
fauna,  it is reasonable to assume
that the  fish  are not affected and
that the  water  is suitable for in-
dustrial use.

   The  examples   given   of such
surveys show  that a  very simple
study of invertebrates can be used
to determine  how  far the effects
of pollution extend, even when it is
no  longer occurring,  and also to
check on  recovery when the pol-
lution is being abated.
L'IMPORTANCE   DES  INVERT-
EBRES DE GRANDE TAILLE DANS
L'ETUDE  DE  LA  POLLUTION
LEGE'RE DES RIVIERES. H. B. N.
Hynes.  p. 235.   H est plus satis-
faisant et plus facile  de se  servir,
du moins pour commencer, depetits
organismes plutot que de poissons,
comme indicateurs de pollution. Une
analyse des invertebres de  grande
taille indique s'il est necessaire de
continuer  les travaux.  Comme un
releve de ce genre n'est pas base
sur une methode rigoureuse  et fixe,
mais flexible,  ceci permet au cher-
cheur d'examiner de nouveau chaque
probleme et  d'interpreter les
resultats a la lumiere  des circon-
stances actuelles.  Si  on ne trouve
que  peu de  change ments dans la
faune des invertebres, ilestraison-
nable de croire que les poissons ne
sont pas affectes et que 1'eau peut
etre utilisee par 1'industrie.

   Les exemples des releves de ce
genre indiquent  qu'une  tres simple
etude des invertebres  peut  etre
utilisee pour  determiner jusqu'ou
les  effets  de  la pollution  se font
sentir,  meme quand  elle a cesse
d'exister et  aussi  pour  verifier
1'epuration quand la pollution est en
train de diminuer.
DIE BEDEUTUNG  DER MAKRO -
WIRBELLOSEN  FUR  DAS  STU-
DIUM GERINGER  FLUSSVERUN-
REINIGUNGEN.  H.  B. N. Hynes.
p. 235 .   Als biologische Anzeiger
von Verunreinigungenverwendt man,
wenigstens  in Vorversuchen,  mit
Vorteil kleine Organisrnen anstatt
Fische.  Eine Analyse der Makro -
Wirbellosen lasst erkennen,  ob ein
Fund ein  eingehendes Studium wert
ist.   Da eine solche  Untersuchung
nicht auf ein starres System auf-
gebaut  ist,   so  erlaubt  sie dem
Forscher, unbeeinflusst jede neue
Fragestellung anzugehen und  sie im
Lichte  der   gerade  herrschenden
Umstande zu erklaren.   Wenn die
Uberpr lifting wenig Xnderung in der
Wirbellosenfauna  zeigt,  dann kann
man annehmen,  dass  Fische nicht
beeinflusst  werden und  dass das
Wasser fur industrielle Zwecke ge-
eignet ist.

   Beispiele fur  solche  Uberpru-
fungen  werden  gegeben,  welche
zeigen, dass  man  durch ein sehr
einfaches  Studium der Wirbellosen
feststellen kann,  wie  weit sich die
Wirkungen der Verunreinigung er-
strecken,  sogar  wenn die Verun-
reinigung  selbst  gar  nicht mehr
besteht; auch kann man nach  Be-
hebung  der  Verunreinigung  den
jeweils  erreichten  Reinheitsgrad
bestimmen.
                                                       402

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THE CONTRIBUTION OF BOTTOM
MUDS  TO THE DEPLETION OF
OXYGEN  IN  RIVERS AND  SUG-
GESTED  STANDARDS  FOR SUS-
PENDED  SOLIDS.    Peter C.  G.
Isaac.    p. 346 .   Questions  are
posed  as  to  whether  bottom muds
in sedimented or resuspended states
contribute to the  oxygen demand of
rivers, and whether  it is  feasible
to impose suspended-solids stand-
ards on effluents to  limit bottom
deposits.  The influence on oxygen
demand of dissimilation  products
from  the sediment is discussed.

   It has been well-established that
bottom  and  resuspended muds  do
exert an oxygen demand.  The rela-
tive contributions of settled deposits
and resuspended  solids  to oxygen
demand vary widely according to the
degree  of  resuspension.   Resus-
pended bottom muds cause a marked
reduction  in  the  dissolved oxygen
concentration.

   Several investigators have con-
cluded  that the oxygen demand of
sludge deposits is independent of the
dissolved oxygen  concentration in
the supernatant water. It is the rate
of upward diffusion to the surface
of the  sediment  of the oxidizable
substances produced  anaerobically
within the deposits that controls the
rate of benthal oxygen demand.

   The extent to which bottom muds
are  resuspended in  flowing water
varies greatly according to circum-
stances prevailing in different
rivers. The amount of resuspension
determines  the degree  of oxygen
depletion, which  is much greater
from suspended  solids than from
stationary bottom deposits. Labora-
tory tests showed that a 1-ppm con-
centration  of detergent  (ABS) de-
creased the  settling rate of  any
given concentration of mud.

   Control of the  amount of sus-
pended solids discharged to a stream
or lake is definitely required.  Such
control will  normally  result in a
relatively non-turbid  stream.  The
quality of  the diluting water  must
be specified  since  water taking up
much dissolved oxygen is, in itself,
of doubtful purity.
CONTRIBUTION  DBS  VASES  DU
FOND  Av LA  DIMINUTION  DE
L'OXYGENE DANS LES  RIVIERES
E^SUGGESTIONS POUR LE CON-
TROLE  DBS  SOLIDES  EN SUS-
PENSION.  Peter C. G. Isaac.p.346.
On se  demande si les  vases  du
fond en depot  au en suspension
pourraient etre  en partie respons-
able  des  quantites  d'oxygene
utilisees par les  rivieVes et s'il y
aurait moyen d'imposer des'etalons
au sujet des solides en suspension
dans les  effluents  afin de limiter
les depots  du fond. On discute  de
1'influence  des produits  de  degra-
dation des sediments sur la demande
d'oxygene.

   II a ete etabli definitivement que
les vases sur  le fond et de nouveau
en suspension utilisentune certaine
quantite d'oxygene.  Les depSts en
sediments et les solides de nouveau
en  suspension ont  des effets bien
varies  sur  1'oxygene  dissous, ces
effets  varient  selon  le  degre  de
suspension renouvelee.   Les vases
du fond en suspension  causent une
reduction tres marquee sur la con-
centration de I'oxyge'ne dissous.

   Plusieurs  chercheurs en  sont
venus a la conclusion que la demande
d'oxygene des  depots  de vases  ne
dependrait pas de la concentration de
1'oxygene dissous dans  la  couche
d'eau  immediatement  superposee.
II  semble que 1'utilisation benthique
de I'oxyge'ne a un taux contr&le par
la  diffusion verticle vers  la surface
de la couche sedimentaire, diffusion
des substances oxydables produites
anaerobiquement au sein meme des
depSts.

   Dans  1'eau courante,  la sus-
pension de  la  vase du fond varie
beaucoup suivant les conditions qui
existent  dans   les  differentes
rivieres.  La quantitS des solides de
nouveau en suspension determine le
degre  de perte  d'oxygene  qui  est
beaucoup  plus grand  lorsque  les
solides  sont en suspension que
lorsqu'ils  sont  deposes au fond.
Des essais de laboratoire ont montre
que 1'additiond'un deter sif del'ordre
de  1-ppm diminue le  taux de sedi-
mentation de  la  vase  quelle qu'en
soit la concentration.

   II faudrait  certainement  etablir
un controle  sur les solides en sus-
pension deverses dans  les  cours
d'eau et les lacs.  Un controle  de
ce genre devrait nor malement avoir
pour resultant un cours  d'eau re-
lativement clair.  II faudrait aussi
tenir compte de la qualite de 1'eau
diluante  (affluent), car  1'eau  qui
utilise  une  grande quantite  de
1'oxygene dissous est surement loin
d'etre pure.
               403
 DER  BEITRAG  DER    BODEN-
 SCHLAMME  ZUR  ERSCHOPFUNG
 DES SAUERST9FFS IN  FLUSSEN
 UNO VORSCHLA'GE VON NORMEN
 FUR  SCHWEBESTOFFE.   Peter
 Charles Gerald Isaac, p. 346. Die
 Fragen  werden  aufgeworfen,  ob
 Bodenschlamme in abgesetztem Oder
 in wieder suspendiertemZustand zum
 Sauerstoffbedarf von  Fliissen  bei-
 tragen und ob  es  moglich 1st, die
 Normen fur  Schwebstoffe auf Ab-
 flifsse zur Abgrenzung der Boden-
 ablagerungen  zu ubertragen.  Der
 Einfluss von  Abbaustoffen des Bo-
 denschlamms  auf   den Sauerstoff-
 bedarf wird besprochen.

    Es ist wohl bekannt, dass Boden-
 schlamm und  wieder suspendierter
 Schlamm den Sauerstoffbedarf ver-
 grossern.   Die  verh'altnismassigen
 Beitrage von  zu Boden gesunkenen
 Ablagerungen und von wieder sus-
 pendierten Feststoffen zum Sauer-
 sfcoffbedarf wechseln sehr inAbhan-
 gigkeit vom Grad der Wiedersupen-
 dierung.  Wieder suspendierte Bo-
 denschlamme  verursachen eine be-
 deutende Verminderung der Konzen-
 tration des   gelosten Sauerstoffs.

    Verschiedene Forscher sind zu
 dem Schluss  gekommen, dass der
 Sauerstoffbedarf von Schlammabla-
 gerungen von  der Konzentration des
 imdaruberstehenden Wasser gelos-
 ten Sauerstoffs unabhangig ist.  Das
 Verhaltnis von Diffusion  nach oben
 zur Oberflache des Bodensatzes der
 anaerob im  Bodensatz   erzeugten
 oxidierbaren  Stoffe  steuert   die
 Grosse des Sauerstoffbedarfs  der
 auf dem  Boden lebenden Fauna.

    Der Grad der Wiedersuspendie-
 rung von Bodenschlamminfliessen-
 dem Wasser ist je  nach den in den
 Fliissen herrschenden Bedingungen
 sehrverschieden. Der Betrag dieser
 Wiedersuspendierung bestimmt den
 Grad der Sauerstoffverarmung,wel-
 cher viel grosser  ist, wenn nicht
 der  unveranderliche   Bodensatz,
 sondern  Sciiwebestoffe    seine
 Ursache sind.  Laboratoriumsver-
 suche zeigten, dass eine Konzentra-
 tion vonlmg/1 eines oberflachenak-
 tiven Waschmittels (ABS) die Senk-
 geschwindligkeit  jeder  beliebigen
 Konzentration  von   Schlamm  ver-
 ringerte.

   Uberwachung  der  Menge  von
 Schwebestoffen,  die  in einen Fluss
 oder  See  entleert werden, ist  be-
 stimmt nStig.   Diese Uberwachung
 wird gewohnlich zu  einem  verhalt-
nismassigklaren Flusswasser fuhren.
 Die Gilte des  Verdilnnungswassers
 muss  angegeben werden,  da  ein
 Wasser,  JaszuvielgelSstenSauer-
 stoff aufnimmt,  schon an und Kir
 sich von zweifelhafter Reinheit ist.

-------
THE USE OF CHARCOAL FOR COL-
LECTING INSECTICIDES IN WATER
SAMPLES.  Charles  C. Van Valin
and  Burton J. Kallman.   p. 250 .
To  replace the time-consuming and
often unreliable method of solvent
extraction  of  water samples, a
method has been devised that utilizes
small quantities of charcoal for the
adsorption of pesticides from rela-
tively small quantities of water. In
practice, 1-gallon  samples of water
are  shaken with 10 grams of char-
coal.   The  charcoal is filtered,
briefly air-dried,  and  sent to the
laboratory for extraction  and  sub-
sequent analysis.  With heptachlor
and  heptachlor epoxide, recoveries
of 60 to  90 percent, respectively,
have been achieved in the 25 to 500
microgram  range,  with  a paper
chromatographic  analytical   pro-
cedure. Recoveries for other pesti-
cides  remain  to  be  determined.
L'UTILITE DU CHARBON DE BOIS
EN VUE DE COLLECTER LES IN-
SECTICIDESDANSDESECHANTIL-
LON D'EAU.  Charles C. Van Valin
and  Burton  J. Kallman.   p. 250 .
Pour remplacer un  essai  a long
terme et souvent une methode  peu
sure  d'extraction  de   dissolvant
d'e'chantillon d'eau, une methode a
ete essayee,  utilissant  de  petites
quantites de charbon  de bois, vu la
quantite'  relativement   petite   de
1'echantillon d'eau, pour 1'absorption
de pesticides.  En pratique, 1-gallon
d'eau est agitee avec 10 grammes de
charbon  de  bois.  Le  charbon de
bois est filtre, legerement seche
a1 1'air et envoye au laboratoire pour
extraction et analyse  complement-
aire. Avec heptachlore et heptach-
lore  epoxide,  recouvrement res-
pectivement a 60 et 90%   ont  'ete
obtenus   dans une domaine de 25 a
500 microgrammes avec un precede
d'analyse utilisant un papier chrom-
atagraphique.  L'etablissement pour
d'autres pesticides reste encore a
determiner.
DIE  ANWENDUNG VON  HOLZ-
KOHLE  ZUM  ENTFERNEN  VON
SCHAD LINGSVERTILGUNGS-
MITTELN  AUS WASSERPROBEN.
Charles  C. Van Valin and Burton
J.  Kallman.   p. 250.   Als Ersatz
fur die zeitraubende und  oft unzu-
verlassige  Methode der Extraktion
von Wasserproben  mit  Losungs-
mitteln wurde  ein Verfahren aus-
gearbeitet, welches kleine Mengen
Holzkohle  fur die  Adsorption von
Schadlingsvertilgungsmitteln   aus
relativ   geringen  Wassermengen
beniitzt.   In der  praktischen  An-
wendung wird eine  Gallone (USA,
etwa 3,79  1)  der Wasserprobe mit
10  Gramm Holzkohle geschiittelt.
Die Holzkohle  wird   abgefiltert,
kurz  an der  Luft getrocknet und
zwecks Extraktion und darauffol-
gender  Analyse ins Laboratorium
geschickt.   Mit Heptachlor (1,4,5,
6,7,7,8-heptachlor-3 %    4, 7, 7 ~-
tetrahydro-4,  7-methanoinden) und
Heptachlorepoxyd  (1,4,5,6,7,8,8-
heptachlor-2, 3-epoxy-3
-------
capable of developing water quality
standards for aquatic organisms is
woefully inadequate at both the state
and federal level.  What  is needed
is a sufficient research staff with
laboratory facilities to develop water
quality  criteria for all recreational
uses of water as  well as for  in-
dustrial and public health purposes.
Standards established and backed by
competent research can exercise a
telling influence for good on pollution
before  it  happens,  and can have a
potent and authoritative effect in the
courts on  those who insist on flouting
the law.
 sante  humaine.    Tres  peu d'in-
 formation sontdisponibles, cepedant
 il y a des  informations des effets
 de polluants varies sur le poisson,
 la vie  sauvage et  le  potential de
 recreation. Lenumbredepersonnes
 techniquement entrainees capable de
 developper  des  programmes  sur
 les  qualities  de   1'eau  pour   les
 organismes  aquatiques est  mal-
 heurseusement non compatible au
 niveau  federal et d'etat.   Ce qu'il
 faut, c'est un personnel suffisant de
 recherche avecdes facilites au point
 de  vue  laboratoires,  afin de de-
 velopper le critere de qualite de
 1'eau,  pour  toutes  les utilites de
 1'eau que  ce soit dans un but  in-
 dustriel, ou de sante publique.

   Les  programmes  etablis et
 soutenus par une recherche compe-
 tente peuvent exercer une influence
 faste sur   la  pollution avant que
 celle-ci se declare et peuvent avoir
 un effet puissant et autoritaire dans
 les tribunauxpour ceux qui persistent
 en se moquant de la loi.
verschiedenen Verunreinigungenauf
Fische,  Wild und  Erholungsmog-
lichkeiten.   Die Zahl der technisch
Ausgebildeten, die fahig sind, Nor-
men  fur  die Giite  des Wassers
gegemiber Wassertieren und Pflan-
zen zu entwickeln, ist vollkommen
unzulanglich  in  den   Vereinigten
Staaten  wie  auch in  den Einzel-
staaten.  Henreichende Forschungs-
kr'afte  mit  entsprechenden  Labo-
ratorienzur Ausarbeitungvon Kenn-
zeichen  der Wassergiite fur  alle
Anwendungen  von Wasser, in In-
dustrie,  zu  Erholungszwecken Oder
zur offentlichen Gesundheitspflege,
sind  notig.    Die so  entwickelten
Normen konnen dann einen grossen
Elnfluss  sogar  auf vermutete Ver-
unreinigungen haben und konnen vor
den Gerichten einestarkeundmass-
gebende Wirkung auf  Gestzesuber-
treter haben.
SALINITY REQUIREMENTS OF THE
FISH CYPRINODON MACULARIUS.
Otto Kinne.  p. 187.  Results are
presented concerning the effects of
salinity on the basic life processes
in the euryhaline and eurythermal
desert  pupfish,   Cyprinodon
macularius.  These results demon-
strate that other environmental fac-
tors, i.e., temperature   and  the
amount  of  dissolved  oxygen, are
capable of  considerably modifying
or  masking the  effects  of salinity
upon growth and  food conversion in
fry and maturing fish and in rates
of embryonic development in eggs.
Experiments were  conducted under
widely different salinity conditions
under which this species is able to
exist and reproduce in nature and in
the laboratory.

   A comparison between fish raised
in freshwater  and others raised in
35°/oo  salinity shows that at lower
temperature levels growth is faster
in  freshwater,  but at the higher
levels  growth  is  faster in 35°/oo
salinity. At 35° C food conversion is
most efficient  at 15°/oo  salinity,
less efficient at 35°/oo salinity, and
least efficient in freshwater.  Con-
version efficiency also depends on
temperature and  other factors such
as food supply and age of the fish.

   Embryonic  development rate  is
progressively   retarded  with in-
creasing salinity. This retardation
is  significantly  affected by  tem-
perature;  the  differences in five
salinity levels  are progressively
augmented as the temperature in-
 CONDITIONS REQUISES DE SALESf-
 ITE  DU  POISSON  CYPRINODON
 MACULARIUS.  Otto Kinne. p. 187.
 Les  resultats  font  voir  les  effets
 de la salinite sur le processus vital
 d'un  poisson du desert, Cypinodon
 macularius,  poission euryhalin  et
 ste'notherme.  Ces resultats demon-
 trent  que les  autres  facteurs du
 milieu, i.e., la temperature et  la
 teneur en oxygene dissous, peuvent
 modifier  considerablement  ou
 masquer  les  effets de la salinite
 sur la croissance et 1'alimentation
 des  jeunes  et  des  adultes  et sur
 le rythme du  developpement  em-
 bryonnaire des oeufs.  On a experi-
 mentalement soumis  ce poisson a
 une grande variete' de conditions de
 salinite dans  lesquelles  il  est en
 mesure d'existeretdesereproduire
 dans  son  habitat  et  au laboratoire.

   Une  comparaison  entre des
 poissons  vivants, les   uns  en eau
 douce et les autres  en une eau de
 salinit^ de 35°/oo demontre que les
poissons croissent plus rapidement
 a basse temperature en eau douce
 mais  plus rapidement a temperature
 elevee dans une eau de salinite de
 35°/oo L'assimilation de la^nourri-
 ture  a  35 °C est  la plus  elevee a
une salinite de 15  /oo moins elevee
 a 35°/oo et la moins elevee  en eau
douce.   Cette  assimilation depend
aussi de la  temperature et de plu-
 sieurs autres facteurs tels  que la
 quantite  de  nourriture et 1'age du
poisson.

   Le rythe de developpement em-
bryonnaire  diminue  alors que la
DER  SALZBEDARF DES FISCHES
CYPRINODON MACULARIUS. Otto
Kinne.   p. 187.    Forschungser-
gebnisse viber die Wirkung des Salz-
gehalts auf grundlegende Lebensvor-
gange im euryhalinen und euryther-
malen "desert pupfish", Cyprinodon
macularius, werden berichtet.  Sie
zeigen, dass andere Umwelteigen-
schaften, namlich Temperatur und
Gehalt an  gelSstem Sauerstoff  die
Wirkungen des  Salzgehalts  auf
Wachstum  und  Stoffwechsel  be-
trachtlich  andern Oder  verdecken
konnen und zwar sowohl in den Ju-
gendformen als auch in den Eiern
selbst durch Anderung  der  Ge-
schwindigkeit  der   Embryonalent-
wicklung.  Versuche wurden inner-
halb der weiten Grenzen des  Salz-
gehaltes,  zwischen  welchen diese
Art leben und sichfortpflanzenkann,
im  Freien  und  im Laboratorium
durchgefuhrt.

   Ein Vergleich zwischen in Siiss-
wasser und in Wasser  mit 35°/oo.
Salzgehalt  aufgezogenen  Fischen
zeigt,  dass das  Wachstum in Su'ss-
wasser  bei   niedrigen,   m  dem
Salzwasper hmgegen  bei hoheren
Temperaturen grosser ist. Bei 35°
C. ist der  Stoffwechsel am besten,
wenn der Salzgehalt 15°/oo. betragt;
erQ ist  wenigner leistungsfahig bei
35 /oo.  Salzgehalt und am gering-
sten in Susswasser. Seine Leistung-
fahigkeit hangt ausserdem noch von
der Temperatur  and von anderen
Umstanden wie Nahrungsversoguing
und Alter der Fische ab.

   Die Geschwindigkeit  der  Em-
                                                       405

-------
creases.  The effects of salinity on
embryonic  development and on its
upper critical and lethal tempera-
ture are highly significant statis-
tically and  easily  reproducible.
Nevertheless,  a  further  analysis
shows that it is not the salinity per
se that causes these effects, but the
concomitant  change  in  the level
of saturation  for  ambient oxygen.
The  results  show that the retar-
dation  effect  observed in  high
salinities  can be  nullified largely
or  completely by  a  rise in  the
amount of dissolved oxygen.

   All  the  data  indicate that  the
importance  of the salinity factor
as part of  the total environment of
Cyprinodon macularlus can only be
fully  appreciated  and  understood
within the framework of a compre-
hensive, poly-factorial analysis.
salinite augmente.  La temperature
a-fecte  cette diminution sensible -
ment;  les  differences qui  existent
entre les  cinq niveaux de salinite
augmentent  progressivement  avec
une augmentation de la temperature.
Les  effets  de  la  salinite  sur le
developpement embryonnaire, surla
temperature ^critique superieure et
sur la temperature fatale sont net-
tement definis au point ^de vue sta-
tistique et  ils peuvent etre repetes
facilement.  Cependant, une analyse
poussee a demontre'e que ce n'etait
pas la salinite per se qui produisait
ces effets mais le changement con-
comitant de 1'oxygene ambiant.  Les
resultats font voir que le retard dans
le developpement embryonnaire ob-
serve  a salinite elevee, peut etre
annul! en grande par tie ou totale-
ment  par une  augmentation de la
teneur en oxygene dissous.

   Toutes les donnees indiquent que
1'importance de la  salinite  comme
facteur du milieu  de  Cyprinodon
marcularius ne peut etre evaluee et
comprise que si on la consider e dans
une analyse poussee comme faisant
partie d'une structure composee de
plusieurs facteurs  agissant les uns
sur les autres.
bryonalentwicklung wird mit zuneh-
mendem  Salzgehalt fortschreitend
verzogert. Diese Verzogerungwird
durch   die  Temperatur   erheblich
beeinflusst; die Unterschiede infiinf
Salzgehalten werden mit Tempera-
turerhohung  stufenweise  grosser.
Die Wirkungen des Salzgehalts auf
die Embryonalentwicklung und auf
ihre obere  kritische und todliche
Temperatur  sind  statistisch sehr
bedeutsam und leicht wiederholbar.
Nichtsdestoweniger  zeigt    eine
weitere Analyse, dassder Salzgehalt
allein  diese  Wirkungen nicht ver-
ursacht, sendern die damit einher-
gehende Anderung des jeweiligen
Sauerstoffsattigungsgrades.     Die
Ergebnisse zeigen, dass die  hem-
mende  Wirkung hoherer  Salzgehalte
weitgehend oder  vollstandig durch
Erhohung der  Menge des gelosten
Sauerstoffs aufgehobenwerden kann.

   Alle Versuchszahlen deuten da-
rauf hin, dass die Wichtigkeit des
Salzgehalts als Teil der Umweltvon
Cyprinodon macularius nur im  Zu-
sammenhang mit einer umfassenden
mathematischen Analyse  voll ver-
standen und geschatzt werden kann.
 ENVIRONMENTAL REQUIREMENTS
 OF EPHEMEROPTERA.  Justin W.
 Leonard,   p. 110.  Much more is
 known  about  the  distribution  of
 Ephemeroptera with regard  to the
 physical  characteristics of the
 environment than  about   their
 reaction to variations in water
 chemistry,    especially  chemical
 variations   introduced by human
 activity.  While general ecological
 requirements of the common species
 are  known,  conditions of micro-
 habitat  have rarely been investi-
 gated; for  many described species
 the immature stages are themselves
 unknown.

   In North America, a considerable
 part  of our knowledge  of mayfly
 ecology  has been gained in con-
 nection  with studies of feeding habits
 and  requirements  of  fishes, es-
 pecially trout,  and with attempts to
 develop  and  evaluate methods of
 environmental manipulation to im-
 prove fisheries.

   In certain parts of  the country,
 studies  of nymphal distribution made
 3  or 4 decades ago have made it
 possible to evaluate  the  effect of
 both gradual and sudden ecological
 changes.   In a few instances re-
 covery  of a mayfly fauna decimated
by natural catastrophe, or by man-
 CONDITIONS  DE  MILIEU DES
 EPHEMEROPTERA.      Justin  w.
 Leonard.    p. 110  .    On  connait
 beaucoup  mieux la distribution des
 Epheme'roptera   en  fonction  des
 caracteres physiques du milieu que
 leur reaction aux variations de com-
 position chimique de 1'eau, particu-
 lierement aux variations introduites
 par  1'activite  humaine. Tandis que
 les necessites ecologiques generales
 sont  connues  pour les  especes
 courantes, les conditions de micro-
 habitat  ont  rarement ete etudiees;
 pour beaucoup d'especes decrites,
 les stades larvaires sont eux-memes
 ineonnus.

   En Amerique  du Nord,  une tres
 grande partie de  nos  connaissances
 sur  1'ecologie des  ephemeropteres
 a Ite obtenue a 1'occasion d'etudes
 sur  la nourriture et  les conditions
 de vie des poissons, particuliere-
 ment de  la truite  et  en relation
 avec les assais faits pour developper
 et evaluer les methodes pour
 1'amelioration des peches.

   En certaines  regions  du pays,
 des  etudes de distribution des
 nymphes effectuees 11 y a trois ou
 quatre decades ontpermisd'evaluer
 les  effets   de    changements
 ecologiques  soit  graduels soit sou-
 dains.  Dans  quelques  cas, la re-
 UMWELTSANSPRUCHE DER EPHE-
 MEROPTERA.     Justin W. Leo-
 nard,  p. 110. Unser Wissen iiber
 die  Verteilung der Ephemeroptera
 hinsichtlich der physikalischen Ei-
 genschaften  ihrer  Umgebung  1st
 viel grosser als  das iiber ihr Ver-
 halten gegemiber  Anderungen in der
 Chemie  des  Wassers,  besonders
 solchen, die durch menschliche Ta-
 tigkeit  verursacht  wurden.  Wah-
 rend die  allgemeinen  Ansprilche
 okologischer  Art fur die gewohn-
 lichen  Arten der  Ephemeroptera
 bekannt  sind, haben  ihre Lebens-
 bedingungen  im Kleinen selten In-
 teresse wachgerufen; von vielender
 beschriebenen Arten  sind sogar die
 Jugendstufen selbst noch unbekannt.

   In Nordanierika sind  betracht-
 liche  Erfahrungen iiber  die  6ko-
 logie  der  Eintagsfliege  im  Zu-
 sammenhang mit Studien iiber Nah-
 rungsaufnahme und Nahrungsbedarf
 von  Fischen, besonders  Forellen,
 sowie  in Untersuchungen zur Ent-
 wicklung und  Auswertung von Ver-
 fahren, die Umwelt zum Vorteil der
 Fischerei  zu beeinflussen,   ge-
 wonnen worden.

   In gewissen Teilen der Verei-
 rigten Staaten  ermoglichten Studien
 iiber das Vorkommen der Nymphen,
 die vor 3 bis 4 Jahrzehnten gemacht
                                                       406

-------
made pollution subsequently brought
under  control,  has  been followed.

   An attempt is made to outline the
status  of  our knowledge of mayfly
requirements to date, and to point
out  problems  in  particular  need
of study.
installation d'une faune d'ephemeres,
decimee par  une  catastrophe
naturelle^ ou par  une pollution
humaine eliminee ensuite, a pu etre
suivie.

   Un  essai est fait pour tracer
1'etat de nos connaissances actuelles
sur les besoins des ephemeropteres
et pour souligner les problemes
necessitant  particulierement  une
etude.
 worden waren, die Auswertung der
 Wirkung  allmahlicher  und  plotz-
 licher okologischer Veranderungen.
 In  einigen  Fallen konnten  solche
 Studien die Erholung einer Eintags-
 fliegenfauna verfolgen, welche durch
 Naturereignisse  Oder  durch  vor-
 iibergehende Verunreinigung infolge
 menschlicher  Tatigkeit   zahlen-
 massig stark zuriickgegangen  war.

   Der Stand  unserer  Kenntnisse
 iiber die Umweltanspruche der  Ein-
 tagsfliege  wird   dargestellt  und
 Fragen, die weiteren Studiums be-
 diirfen, werden aufgezeigt.
FACTORS  WHICH AFFECT THE
TOLERANCE  OF  FISH TO HEAVY
METAL  POISONING.    R. Lloyd.
p. 181        .    Recent  research
on  the  toxicity  of zinc,  lead, and
copper salts to rainbow trout at the
Water Pollution  Research  Labor-
atory, England,  has been directed
towards a  study of the mechanism
of  toxic action and  the  effect of
some chemical  and physical com-
ponents of  the environment on their
toxicity.

   Histological examination  of the
gills of rainbow trout killed by these
poisons showed  that  the  epithelial
cells  of the  lamellae  were  de-
stroyed; no precipitation  of mucus
was observed.

   When  the  log  concentration of
these metals is  plotted against the
log median period of  survival of
rainbow trout, the relation between
them  is curvilinear  and, after  a
period of time,  the curve becomes
parallel to  the survival time axis.
This indicates that a lethal thres-
hold concentration exists which will
kill only 50 percent of a population
of rainbow trout even after prolonged
exposure,  and that variations in the
susceptibility of these fish to heavy
metal poisoning  caused by differ-
ences in the chemical and physical
nature of the  environment are  best
measured by the change in the lethal
threshold concentration.

   For zinc, lead, and copper, the log
lethal  threshold  concentration in-
creases linearly with  the log total
hardness of the  water, although the
slopes of  the lines obtained with
different metals are not the same.
Although an increase in temperature
reduces the survival  time of rain-
bow trout in zinc solutions, the lethal
threshold   concentration  does  not
vary  to an appreciable extent.  A
reduction  in the  dissolved oxygen
content  of  the water  reduces the
lethal  threshold  concentration of
 FACTEURS AFFECTANT LA  TO-
 LERANCE DES POISSONS A L'EM-
 POISONNEMENT PAR LES METAUX
 LOURDS.  R. Lloyd,  p. 181.   Au
 Laboratoire des Recherches sur la
 pollution  de  1'eau, Angleterre, les
 travaux recents sur la toxicite des
 sels de zinc, de plomb et de cuivre
 pour  la  truite arc-en-ciel ont ete
 orientes  vers  1'etude de mode
 d'action des  substances toxiques et
 de  1'effet de certains facteurs
 chimiques et  physiques  du milieu
 sur leur toxicite.

   On  a  examine  les truites arc-
 en-ciel dont la  mort a ete causee
 par  ces  poisons.    L'examen  his-
 tologique  de leurs branchies a. revele
 que  les  cellules  epitheliales  des
 lamelles  avaient  ete detruites; on
 n'a observe aucune precipitation du
 mucus.

   Lorsque le logarithme de la con-
 centration de  ces  metaux  est
 rapporte  sur un graphique avec  le
 logarithme du  mode du  temps de
 survie de la truite arc-en-ciel, on
 obtient une ligne  courbe  qui  apres
 un certain^ temps  devient parallele
 a  1'ordonee  du temps de survie.
 Ceci  indique qu'il existe un seuil
 des  concentrations  f a t a 1 e s  qui
 causera la mort de  seulement 50%
 d'une  population de  truits arc-en-
 ciel,  meme  apres une  exposition
prolongee.   Cette courbe indique
 aussi que les  variations de la sen-
 sibilite de ces  poissons  a  1'em-
poisonnement par les metaux lourds,
variations qui sont causees par les
differences  dans  la  composition
 chimique et physique du milieu,  sont
mieux  mesurees par le changement
du seuil des concentrations fatales.

   Pour  le zinc,  le plomb  et  le
 cuivre, le logarithme de la limite
de concentration augmente directe-
ment avec la logarithmedeladurete
de  1'eau,  bien  que  la  pente  des
segments  de droites obtenues sur le
graphique ne soit pas la meme pour
UMSTANDE,  WELCHE   DIE TO-
LERANZ      VON    FISCHEN
GEGENUBER     VERGIFTUNGEN
DURCH SCHWERMETALLE BEEIN-
FLUSSEN. R. Lloyd. pJSl.Kurzlich
unternommene Untersuchungenuber
die Giftigkeit von Zink -, Blei - und
Kupfersalzen gegeniiber der Regen-
bogenforelle  am  Water  Pollution
Research  Laboratory,  Stevenage,
England gingen in Richtung eines
Studiums   des  Mechanismus  der
Giftwirkung  und  des   Einflusses
gewisser  chemischer und physika-
lischer  Umweltfaktoren  auf  die
Giftigkeit.

   Die  Gewebeuntersuchung  der
Kiemen   von   Regenbogenforellen,
welche  durch  diese Gifte  getotet
worden waren, zeigte, dass die Epi-
thelzellen  der  Lamellen  zerstort
waren;  Schleimabsonderung  wurde
nicht beobachtet.

   Wenn die Logarithmenwerte der
Konzentration dieser Metalle gegen
die Logarithmender mittlerenUber-
lebenszeiten von   Regenbogenfo-
rellen zeichnerisch dargestellt wer-
den, so erhalt man eine gekrummte
Linie,  die nach einer gewissen Zeit
in  eine Parallele zur Uberlebens-
zeitachse iibergeht.   Das bedeutet,
dass es einen Schwellenwert  derje-
nigen  Todesgabe  gibt, welche nur
50% einer Regenbogenforellenbevol-
kerung sogar nach langer Einwirkung
toten wiirde, ferner, dass Anderun-
gen in  der Empfindlichkeit  dieser
Fische  gegen Schwermetallvergif-
tungen, welche durch Unterschiedin
der  chemischen und physikalischen
Natur  der  Umwelt  bedingt waren,
am besten durch die Anderungendes
Schwellenwertes   der   Todesgabe
gemessen werden.

   Fur  Zink, Blei und Kupfer steigt
der  Logarithmus  des  Schwellen-
wertes  der Todesgabe linear  mit
dem Logarithmus  der  Gesamtharte
des  Wasser an, aber der Neigungs-
winkel  der  Geraden  1st fur jedes
                                                      407

-------
these poisons, and the extent of the
reduction is approximately the same
for each metal; a hypothesis has been
constructed to cor relate the ob-
served increase in toxicity with the
increased flow of respiratory water
through  the  gills.   Similarly,  a
greater activity on the part  of the
fish increases its  susceptibility to
poisons by increasing  respiratory
flow.

   For  rainbow trout,  the  lethal
threshold concentration of a mixture
of copper and zinc salts, in either
hard or soft water, is achieved when
the sum of  the concentrations of the
individual metals, expressed as pro-
portions  of their  individual lethal
threshold  concentrations,   equals
unity.   It has been found that this
method of  summing  toxicities also
applies to mixtures of ammonia and
zinc.  Recent  experiments on the
toxicity of  sewage effluents, which
can contain zinc, copper, and am-
monium salts, have shown that in the
majority of the tests  made, pre-
dictions of the toxicity of the effluents
from their chemical analysis were
in  close agreement  with their ob-
served toxicities.
chacun des metaux.  Dans les so-
lutions de zinc quand Pelevation de
la temperature  diminue le temps
de survie de la truite  le seuil des
concentrations fatales  ne varie pas
de facon appreciable.  Une diminu-
tion du  contenu  en oxygene dissous
dans 1'eau fait baisser le seuil des
concentrations  fatales  de   ces
poisons.   La baisse du  seuil est
approximativement  la  meme  pour
chaque metal. Onafaitunehypothese
pour  etablir une correlation  entre
1'augmentation  observee dans  la
toxicite  et  1'augmentation de la
quantite  d'eau passant  par les
branchies pour la respiration. D'une
maniere semblable, une plusgrande
activite de la part  du  poisson aug-
mente sa sensibilite auxpoisons par
une  plus grande  quantite  d'eau
passant par  les branchies.

   Pour la truite arc-en-ciel, en eau
douce ou en eau dure, le seuil des
concentrations fatales d'un melange
de  sels  de   cuivre  et  de  zinc est
atteint lorsque la somme des con-
centrations  de  chacun des metaux
egale 1'unite.   Ces concentrations
sont sous forme de proportions du
seuil des concentrations fatales in-
dividuelles.   On a aussi trouve que
cette   methode  d'addition  des
toxicites  s'applique  aussi aux
melanges d'ammoniaque et de zinc.
Des travaux recents effectues sur
la  toxicite  des eaux  d'egout, qui
peuvent contenir du zinc etdu cuivre
et  des   sels  d'ammonium, ont
demontre que dans la  majorite des
ces etudies  les predictions de
toxicite  basees  sur les analyses
chimiques se rapprochent bien pres
des toxicites observees.
Metall  ein  anderer.   Obwohl ein
Temperaturanstieg die Uberlebens-
zeit der Regenbogenforelle in Zink-
losung vermindert,  so  andert sich
dochdieGrossedes Schwellenwertes
der Tociesgabe nicht merklich. Eine
Verminderung der Konzentrationdes
im Wasser gelostenSauerstoffs ver-
ringert den Schwellenwert der To-
desgabe  dieser  Gifte;  ferner  1st
grossenweise die Verminderung un-
gefahr  die  gleiche  fur jedes der
drei Metalle.  Eine Hypothese wurde
aufgestellt,  welche die  beobachtete
Zunahme  der  Giftigkeit mit dem
vermehrten Durchfluss des Atem-
wassers durch die Kiemen in Zu-
sammenhang zu bringen sucht.   In
ahnlicher Weise vermehrt grossere
Aktivitat des  Fisches  seine Emp-
findlichkeit  gegen Gifte wegen der
Zunahme der  Menge des Atmungs-
wassers.

   Fur die Regenbogenforelle  wird
der Schwellenwert der  Todesgabe
einer  Mischung von  Kupfer  - und
Zinkalzen inhartemoder inweichem
Wasser dann  erreicht, wenn die
Summe  der Konzentrationen eines
jeden einzelnen dieser Metalle (aus-
gedruckt  als   Verhaltnisse  ihrer
Schwellenwerte der Todesgaben zu-
einander) gleich eins 1st. Es wurde
gefunden,  dass  dieses  Verfahren,
die Giftigkeiten zusammenzuzahlen,
auch auf Mischungen von Ammoniak
und Zink anwendbar 1st.  Versuche,
welche   kurzlich   bezuglich   der
Giftigkeit vonAbwassern,die Zink-,
Kupfer  - und  Ammoniumsalze ent-
halten  konnen, gemacht  wurden,
zeigten, dass in der  Mehrzahl der
ausgefiihrten Versuche Voraussagen
uber  die Giftigkeit  der Abwasser
auf Grund der  chemischen Analyse
in guter  Ubereinstimmung mit den
beobachteten Giftigkeiten waren.
 THE INFLUENCE OF PREDATION
 ON THE COMPOSITION OF FRESH-
 WATER COMMUNITIES.  T.T.
 Macan.  p. 141.  The  invertebrate
 fauna of a fishpond that held no fish
 was studied for 5 years.  A large
 population  of  trout was then in-
 troduced.   Numbers of most in-
 vertebrates remained unchanged.

    The  number of  planarians in a
 stream increased enormously after
 the onset of mild pollution.  It is
 thought that their food supply was
 improved.   Decrease  of some in-
 sects is attributed  to predation by
 the planarians.

    In the littoral regions  of rich
 lakes  there are  many species and
 individuals of  Mollusca, Malacost-
 INFLUENCE DE LA PREDATION
 SUR LA COMPOSITION DES POPU-
 LATIONS D'EAU DOUCEV  T. T.
 Macan.  p. 141.  On a etudiependant
 5 ans  la laune  d'invertebres dans
 un  etang qui  ne contenait pas de
 poisson.   On y  a ensuite introduit
 une large population de truites.  Le
 nombre de la plupart des invertebres
 est  demeure le meme.
    La nombre de planaires dans un
 cours d'eau semble augmenter con-
 siderablement desqu'onydeceleune
 legere pollution.  On croit que ceci
 serait  du a une  amelioration dans
 la quantite de nourriture. La diminu-
 tion du nombre de certains insectes
 serait  causee par les planaires  qui
 en font leur proie.
 DER EINFLUSS DER NAHRUNGS-
 VERSORGUNG  AUF  DIE  ZUSAM-
 MENSETZUNG  DER FRISCHWAS-
 SERLEBEWELT.T. T. Macan.p0,141,
 Die Wirbellosenfauna eines Fisch-
 teiches, in welchem  Fische  nicht
 gediehen,  wurde  fiinf Jahre  lang
 beobachtet. Dann wurde eine grosse
 Anzahl von Forellen ausgesetzt. Die
 Zahl der meisten Wirbellosen blieb
 unverandert.

    Nach einer geringen Verunreini-
 gung stieg in einem Fluss die  Zahl
 der Planarien ausserordentlich. Es
 wird angenommen,  dass sich  ihre
 Nahrungsversorgung    verbessert
 hatte.  Die Verminderung der  Zahl
 gewisser Insekten wird auf die Nah-
 rungsbediirfnisse   der   Planarien
 zuriickgefuhrt.
                                                        408

-------
raca, Oligochaeta, and Platyhelmin-
thes, and comparatively few of in-
sects.  Oligotrophic lakes are
characterized by the predominance
of insects and relative  scarcity of
the  other groups.  It is uncertain
whether the non-insect groups, many
members of  which  have  entered
fresh  water  from the  sea,  are
favored more by the  abundant food
supply or the rich ionic content of
eutrophic lakes. It is suggested that
they eat the  eggs  of insects, many
of which  are scattered in a hap-
hazard way, and young active stages
too,  thereby bringing about the
paucity of these animals.   Their
own  eggs  are  generally  laid  in
capsules, or gelatinous  masses, or
retained in a brood pouch.
    Sur le  littoral  des  lacs  tres
 productifs  on  trouve  un  grand
 nombre d'especes  et d'individus de
 Mollusques, Mallocostraces, Oligo-
 chetes et Plathelminthes, et com-
 parativement peu d'insectes.  Les
 lacs oligotrophiques sont character-
 ises par  une predominance d'in-
 sectes et une  rarete relative des
 autres groupes. II est difficile de
 determiner  la  cause  exacte de la
 grande abondance des groupes non-
 insectes dont plusieurs sont passes
 de  la  mer  £  1'eau  douce.  Cas
 conditions serient  dues,  soit a une
 plus grande abondance de nourriture,
 soit a un  riche contenu ionique des
 lacs eutrophiques.   On  croit que
 ces groupes se nourrissent d'oeufs
 d'insectes  disperses  ca et la  et
 aussi de jeunes  larves, cequiamene
 une diminution considerable  du
 nombre d'insectes.   Par contre,
 leurs  propres oeufs sont generale-
 ment pondus en masses gelatineuses
 ou capsules ou ils sont retenus dans
 un sac a couvee.
   In den Ku'stengebieten von Seen,
die reich an vielen Arten und Ein-
zeltieren  von Mollusca, Malacos-
traca, Oligochaeta und Platyhelmin-
thes  sind, findet  man  verhaltnis-
massig  wenige Insekten. Oligotro-
phische Seen sind durch das Vor-
herrschen von  Insekten und  eine
relative Armut an den anderen Grup-
pen  charakterisiert.    Es ist  un-
bestimmt, ob die Nicht  - Insekten-
gruppen, von denen viele vom Meer
aus in die Frischwasser wanderten,
mehr vom Nahrungsreichtum oder
vom hohen lonengehalt eutrophischer
Seen begtinstigt sind.  Es wird vor-
geschlagen,  dass sie Insekteneier,
deren viele  wahllos verstreut sind
und auch  junge aktive Formen ver-
tilgen und dadurch die Armut  an
diesen  Tieren verursachen.   Ihre
eigenen Eier werdenimallgemeinen
in Kapseln,  oder in Gallertmassen
gelegt  oder  in  Bruttaschen   zu-
riickgehalten.
PESTICIDE POLLUTION STUDIES
IN  THE SOUTHEASTERN STATES.
H.  Page  Nicholson,   p. 260.   In-
vestigations  were  begun  in 1959
on pesticide pollution of surface and
ground water to determine how gen-
erally this pollution occurs,  its
less obvious side effects on aquatic
life, factors relating to the presence
or absence of selected pesticides in
water, how well they  are removed
from potable water by treatment, and
what can  be done to  alleviate such
pollution.  Toxaphene and the gamma
isomer of BHC were found in drain-
age  from a 400-square mile river
basin where cotton is a main crop.
Water treatment failed  to remove
either insecticide from a municipal
water  supply.    The maximum
quantity  recovered was 0.4 parts
per  billion of  toxaphene and  0.75
parts  per  billion of gamma BHC.
Sampling  and analytical  techniques
were  not  totally efficient  in re-
covering all that was present. Al-
though toxaphene was present in the
water  nearly year around,  no ad-
verse effects were evident on aquatic
life.

   In a study of parathion in a peach
orchard, that insecticide was shown
to survive for  at least nine months
in the soil, and to  reach  a farm
pond by means  of runoff with  rain
water  and directly  as wind-blown
spray.   Again  no  adverse effects
on  aquatic life  were demonstrated
from several month's exposure
where the maximum recovered con-
centration was 1.2 parts per billion.
Chironomid larvae, however, were
 ETUDES  DES POLLUTIONS PAR
 PESTICIDES DANS LES ETATS DU
 SUD-EST. H. Page Nicholson.p. 260.
 Des recherches furent entreprises
 en 1959 sur la pollution des eaux de
 surface et des eaux souterraines par
 les  pesticides.   II  s'agissait de
 determiner comment survient cette
 pollution,  ses effets  les moins
 evidents  sur  la  vie aquatique,  les
 facteurs relatifs  a la presence ou a
 1'absence de pesticides selectionnes
 dans 1'eau, jusqu'a quel point ces
 crops sont elimines de 1'eau potable
 par traitement et ce qui peut etre
 fait pour diminuer une telle pollution.
 Le Toxaphene  et 1'isomere gamma
 du BHC ont ete  trouves dans  les
 eaux de drainage d'un bassin de 400
 milles  carre  ou le coton est la
 culture principale.  Les traitements
 de 1'eau dans une station d'alimenta-
 tion municipale ne peuvent eliminer
 aucun  insecticide.   Les quantites
 maximum trouvees furent 0.4 parties
 par  billion  de Toxaphene  et 0.75
 parties per billion de BHC gamma.
 Mais 1'echantillonnage et les techni-
 ques d'analyse n'etaient pas suf-
 fisamment efficients pour retrouver
 tout ce qui  etait  present.  Quoique
 le toxaphene soit present depuis pres
 d'un an aucun effet contraire n'etait
 apparent pour la vie aquatique.

   Dans 1'etude du parathion dans un
 verger a peches, cet insecticide a
 subsiste  au moins neuf  mois dans
 le sol, ainsi que  dans une mare de
ferme  atteinte par  les  eaux  de
 ruissellement et par les poussieres
poussees par le vent.   La  encore,
aucun effet contraire n'a ete constate
STUDIEN  UBER WASSERVERUN-
REINIGUNG DURCH SCHADLINGS-
BEKAMPFUNGSMITTEL  IN  DEN
SUDOSTLICHEN STAATEN DER U.
S.A.  H. P. Nicholson,  p. 260.  Im
Jahre 1959 wurden Studien iiber die
Verunreinigung  von Oberflachen -
und Grundwasser durch Schadlings-
bekampfungsmittel unternommen; es
sollte festgestellt werden, wie weit
die  Verunreingung  verbreitet ist,
welche weniger in die Augen fallen-
den  Nebenwirkungen  sie  auf das
Leben im  Wasser  ausu'bt,  welche
Faktoren das  Vorkommen oder die
Abwesenheit gewisser ausgewahlter
Schadlingsbekampfungsmittel    im
Wasser bedingen, zuwelchem Grade
ihre Beseitigung durch Behandlung
des  Trinkwassers moglich  ist und
schliesslich, was zur Verminderung
der  Verunreinigung vorgenommen
werden  kann.   Toxaphen und das
gamma  - Isomer von BHC (1,2,3,4,
5,6- Hexachlorcyclohexan) wurden
in der Entleerung eines etwa 1000
Quadratkilometer  grossen  Fluss-
beckens gefunden, inwelchemhaupt-
sachlich Baumwolle geerntet wird.
Keine  dieser  beiden  Substanzen
konnte durch Behandlung  des Was-
sers einer  stadtischen Wasserver-
sorgungsanlage entfernt werden. Die
Hochstmenge, die wieder zuriickge-
wonnen   werden  konnte,  war  0,4
Teile/Milliarde Toxaphen und 0,75
Teile/Milliarde gamma BHC.  Pro-
benahme und  analytische  Untersu-
chungsverfahren waren nicht fahig,
die Gesamtmengen der Schadlingsbe-
kampfungsmittel in  den Proben zu
erfassen.   Obwohl  Toxaphen fast
wahrend des ganzen JahresimWas-
                                                       409

-------
reduced  in number of exposure of
the adult population to spray in the
terrestrial environment. The effects
of an  industrial  spill of parathion
were evident in a major river 100
miles downstream from the point of
discharge.

   Occurrence  in  surface water of
pesticides  in  quantities below the
level  acutely  toxic to aquatic life
may be  rather common  in  areas
where pesticides are used routinely.
The threshold below which harm is
caused by such pollution remains to
be determined since evaluation of
chronic  exposure effects at  low
levels  is very difficult. More work
in this area is  critically needed.
sur la vie aquatique apres plusieurs
mois d'expositionaune concentration
maximum de 1.2 parties per billion.
Cependant  les  larves  de chirono-
medes  etaient moins  nombreuses
pares exposition des adultes a une
vaporisation sur les terres environ-
nantes.   Les  effets d'un epandage
industriel  de   parathion  furent
evidents dans  une  grande riviere,
100  milles a  1'aval  du point  de
deversement.

   La presence de  pesticides dans
les eauxde surface, en concentration
inferieure  au  niveau rapidement
nocif,  peut etre  assex frequente
dans les regions ou des pesticides
sont couramment utilises.  Le seuil
au dessous duquel un effet dangereux
est provoque par une telle pollution
reste a  determiner puisque  1'es-
timation des effets d'une exposition
continue a de faibles concentrations
est  trls  difficile.    Des travaux
complementaires sont necessaires
en ce domaine.
ser gefunden wurde, so wurdendoch
keinerlei Beweise fiir seine ungun-
stigen Einfliisse auf im Wasser le-
bende Pflanzen Oder Tiere gefunden.

   In einem Pfirsichgarten konnte
Parathion  (o,o-diathyl-o,  p-nitro-
phenylphosphorothioat) noch nach 9
Monaten im  Boden  nachgewiesen
werden; auch konnte gezeigtwerden,
dass es sowohlinabfliessendemRe-
genwasser  als auch durch Windzer-
staubung  den  Weiher   in einem
Bauernhof erreicht hatte.  Auchhier
konnten  nach mehreren  Monaten
keine ungunstigen  Einflusse auf das
Leben imWasser festgestellt werden,
trotzdem die zuruckgewonnene Hoch-
stkonzentration  1,2   mg/1  betrug.
Die  Zahl von  Chironomid Larven
ging aber zuriick, wenn die erwach-
senen Formen auf dem  Lande der
Zerstaubung ausgesetzt waren. In
einem grosseren Fluss zeigten sich
die  Wirkungen eines industriellen
iiberlaufs,  der Parathion enthielt,
noch 160 km stromabwarts der Ein-
leitungsstelle.

   Das Vorkommen von Schadlings-
bekampfungsmitteln in Oberflachen-
wasser inMengenunter denfiirWas-
serorganismen akut giftigen durfte
in Gegenden, wo diese Stoffe laufend
verwendet  werden,  ziemlich  all-
gemein sein.  Der  Schwellenwert,
unterhalb dessen eine derartige Ver-
unreinigung schadlich wirkt,  muss
erst noch bestimut werden, da die
Auswertung von  chronischen  Wir-
kungen   kleiner   Mengen    sehr
schwierig  ist.    Mehr  arbeit auf
diesem Gebiet ist dringend notig.
 ALGAE  AS INDICATORS OF POL-
 LUTION.   Ruth Patrick,  p. 225 .
 During the twentieth century a great
 deal  of literature has accumulated
 pertaining to algae as indicators of
 pollution.   The word "pollution* is
 a collective noun referring to many
 chemical and physical changes that
 may  occur  in  a body of water due
 to the activities of man.  The  first
 kind  of  pollution  recognized was
 organic  in  nature.   Species were
 classified as to the degree of organic
 pollution they could tolerate.  Little
 attention was given to the  sizes of
 the population of the various species
 or  to the  structure of  the algae
 community  as a whole. The presence
 or  absence of a  few  or  several
 species  were  used to indicate the
 degree of pollution.  Further work
 showed that this method of indicat-
 ing pollution often  was misleading.
 At  about the  same time,  several
 workers developed a system of in-
 dicating pollution by  the kinds of
 species  that  were dominant in  an
 algal community. Several examples
 LES  ALGUES   CONSIDEREES
 COMME INDICATEURS DE POL-
 LUTION.  ^Ruth Patrick,   p. 225 .
 Depuis le debut  du vingtieme siecle,
 de nombreus articles ont paru con-
 cernant  les  algues  comme  in-
 dicateurs  de pollution.    Le  mot
 ^pollution^ etant un nom collectif
 designant les nombreux changements
 chimiques et physiques pouvant ap-
 paraitre dans une eau par suite des
 activites  humaines.  La premiere
 sorte  de  pollution  reconnue etait
 d'origine organique.  Les  especes
 furent classics selon  le degre de
 pollution  organique  qu'elles pou-
 vaient tolerer.   Peu d'attention fut
 apportee a 1'importance des popu-
 lations  des differentes especes ou
 a la  structure  de  la communaute
 algale dans  son ensemble.    La
 presence ou 1'absence  de quelques
 especes  ou  de   plusieurs  especes
 servait a indiquer  le degre de pol-
 lution.  Des travaux ulterieurs ont
 montre  que cette  methode etait
 souvent  erronee.   A peu pres en
 me'me temps plusieurs chercheurs
ALGEN   ALS  LEITORGANISMEN
DER  WASSERVERUNREINIGUNG.
Ruth Patrick,   p. 225   .Im Laufe
des  20.   Jahrhunderts  sind zahl-
reiche  Arbeiten  iiber  Algen   als
Leitorganismen der Wasserverun-
reinigung  erschienen.  Das Wort
 ,,Verunreinigung"  ist  ein Sammel-
wort fiir die vielen chemischen und
physikalischen     Veranderungen,
welche in einem Wassersystem in-
folge  menschlicher Tatigkeit  vor-
kommen konnen. Die erste Art von
Verunreinigungen,  die  als  solche
erkannt  wurde, war  ihrem Wesen
nach organisch.  Man unterschied
die Arten von Organismen nach dem
Grade der organischen Verunreini-
gung,  welche  von ihnen  ertragen
wurde.  Wenig   Aufmerksamkeit
wurde der Grosse der Bevolkerung
der  verschiedenen Arten oder dem
Aufbau der  Algenflora als Ganzem
geschenkt.   Die Anwesenheit  Oder
Abwesenheit einer geringen Zahl von
Algen Oder  einiger weniger Arten
zeigte den Grad der Verunreinigung
an.  Spatere Arbeiten  zeigten,  dass
                                                        410

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are given in which this method was
used.

   With  the  increased  complexity
of civilization the word "pollution"
included a greater number of sub-
stances that had very different
chemical  and physical characteris-
tics.    Thus, the general use  of
indicator  species  become  much
more difficult.  It has been shown
further that variations in the natural
environment may greatly  influence
the size of the populations of "in-
dicator species*  and  even  their
occurrence. Thus, well established
populations  of  several  species  of
algae may indicate the presence of
certain types of pollution,  but a de-
crease  in the sizes of their popu-
lation or  their absence may be due
to very  different  causes than  a
change  in the  amount of  pollution
present.

   In  recent years the importance
of considering the structure of the
whole algae community as well  as
the kinds of species composing it
has  been  pointed out by several
workers.  Examples are given as to
the ways  in which various kinds of
pollution  may affect the  structure
of algae communities and  the kinds
of species composing them.
developperent un systeme ou la pol-
lution  etait  decelee  d'apres  les
especes   dominantes  dans  la
communaute  algale. Plusieurs ex-
emples sont donnes en utilisant cette
methode.

   Avec la crossante complexite de
la  civilisation,  le  mot ~~'pollution*
englobe un  plus grand nombre de
substances  qui  ont des caracte-
ristiques  chimiques  et physiques
tres differentes, aussi 1'emploi
general d'espe'ces  indicatrices
divient bsaucoup plus difficile.  II a
ete  montre que des variations du
milieu  naturel  peuvent influencer
enormement   1'importance   de  la
population des especes dominantes
et meme  leur presence. Aussi des
populations  bien  etablies  de
plusieurs  especes  d'algues peuvent
indiquer   la presence  de certains
types de pollution,  mais une diminu-
tion de quantite  ou mSme leur dis-
parition peuvent etre  dues a  des
causes  autres  qu'un   changement
dans la pollution presente.

   Ces dernie'res annees plusieurs
chercheurs ont souligne  1'im-
portance de considerer la structure
de toute la communaute algale aussi
bien que les especes la composant.
Des exemples sont donnes sur la
maniere dont  ces elements peuvent
etre affectes par differentes sortes
de pollution.
dieses  Verfahren  oft  irrefuhrend
war.   Etwa zur gleichen Zeit ent-
wickelten  verschiedene  Forscher
eine  Methode,  welche den  Ver-
schmutzungsgrad durch die in der
Algenflora vorherrschenden  Arten
anzeigte.  Einige Beispiele der An-
wendung dieses  Verfahrens werden
besprochen.

   Gleichlaufend  mit dem immer
verwickelter werdenden Aufbau un-
serer Zivilisation musste auch das
Wort MVerunreinigung" eine immer
grossere  Zahl von Stoffen, die sich
in ihren  chemischen und physika-
lischen  Eigenschaften sehr vonein-
ander   unterschieden,   umfassen.
Dadurch wurde der allgemeine Ge-
brauch  von  Leitorganismen   viel
schwieriger.   Ausserdem  lernte
man,  dass  Veranderungen in  der
natiirlichen Umgebung die Zahl der
Leitorganismen   und   manchmal
sogar ihr  Vorkommen sehr wesent-
lich beeinflussen konnen. So mogen
z. B. mehrere Arten Algen in gut
wachsenden Bestandendie Anwesen-
heit gewisser Formen von Veiun-
reinigungen anzeigen; jedoch konnte
eine Verminderung  der Grosse der
Algenflora, oder gar ihre Abwesen-
heit durch viele andere Ursachen
als durch  einen  Wechsel in der
Menge der  Verunreinigungen  her-
vorgerufen werden.

   Seit kurzemwirdvonverschiede-
nen Forschern die  Wichtigkeit des
Aufbaus  der gesamten Algenflora
und der verschiedenen Arten in ihr
betont.   Beispiele  dafur, wie die
verschiedenen Arten von Wasser-
verunreinigung den  Aufbau der Al-
genflora und der in ihr  auftreten-
den Arten beeinflussen konnen, wer-
den gegeben.
 ACCUMULATION OF CESIUM-137
 THROUGH THE  AQUATIC FOOD
 WEB.  Robert C. Pendleton. p. 355.
 Cesium-137 is more available  to
 organisms living in aquatic environ-
 ments than in terrestrial environ-
 ments; consequently, foods of man
 that  come from aquatic or wet-land
 sources may contain much more of
 this isotope than foods from normal
 cropland.   The increase in avail-
 ability in  aquatic situations results
 from movement of the cesium ions
 through water directly to the plant
 surfaces before they are immobil-
 ized by mud or other non-living sur-
 faces. Concentrations of cesium-137
 in aquatic animals are directly re-
 lated to the trophic levels,  with the
 highest levels occurring in the flesh
 of predators. The content of cesium-
 137  in tissues of omnivores lies
 between that of herbivores and
ACCUMULATION DE CESIUM 137
DANS  LES TISSUS D'ANIMAUX
AQUATIQUES. Robert C. Pendleton.
p. 355 .   Le cesium 137 est plus
frequemment  recontre   dans  les
organismes vivants dans des milieux
aquatiques que  dans des  milieux
terrestres; en consequence, lanour-
riture,  consommee  par  1'homme
venant de  source aquatique ou de
marais peut contenir beaucoup plus
de cette isotope que les nourritures
venant   d'organisme  terrestre.
L'accroissement  de cette disponi-
bilite dans les situations aquatiques
resulte du mouvement des ions du
cesium  a travers 1'eau jusqu'aux
plantes de surface avant qu'ils soient
arretes  par  le  boue  ou  d'autre
organes morts. Les concentrations
de  cesium 137 dans les animaux
aquatiques sont directement en
rapport avec  les niveau ^trophic3"
 ANREICHERUNG  VON  CAESIUM-
 137 DURCH DEN NAHRUNGSKREIS-
 LAUF  IM  WASSER.    Robert  C.
 Pendleton.   p.  355.   Caesium-137
 ist fur im Wasser lebende Organis-
 men  leichter zuganglich  als  fur
 Landorganismen;  folglich  konnen
 menschliche  Nahrungsmittel,  die
 aus dem Wasser oder aus feuchten
 Landstrichen  stammen,  mehr von
 dieser Atomart  enthalten als solche
 von normalem   Ernteland.   Die
 grossere  Zuganglichkeit aus feuch-
 ten Lagen ergibt sich aus der Be-
 weglichkeit der  Caesiumionendurch
 das  Wasser  unmittelbar  zu  den
 Pflanzenoberfla'chen,  ehe sie durch
 Schlamm oder andere nicht - leben-
 de Stoffe unbeweglich gemacht wer-
 den.  Die  Caesium-137 Kbnzentra-
 tion in Wassertieren hangt unmittel-
 bar mit der  Ernahrungsstufe zu-
 sammen und die hochsten Konzen-
                                                       411

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predators.   The step-wise increase
of cesium-137 concentration in the
successive trophic levels is  related
to the difference  in the biological
half-lives of cesium and potassium.
Because  the biological  half-life of
cesium is about three times longer
than that of potassium, the organism
comes to a  steady state at  a con-
tamination level for cesium greater
than the level in its food. Predacious
fish may accumulate  cesium-137
to 10,000 times the amount in water,
and a comparison of  concentration
factors  and yield per  hectare of
animal products from grazing lands
and fish farming indicates a greater
potential  hazard from the  latter.
High  availability of  cesium-137 to
aquatic  and  emergent plants in-
dicates  that milk and  meat from
grazing animals utilizing forage
from  wetlands  may contain much
more cesium-137  from fallout than
such products from drylands. Thus,
observed  geographic variations in
cesium-137  content of milk may be
in part a result of different levels
of  uptake by  plants of wet and of
dry lands.  Because environmental
variations cause great differences in
uptake of cesium-137, evaluation of
the hazard to man  from this  isotope
should be made on local rather than
regionwide  bases.  Hazards eval-
uation, as presented, is limited to
freshwater conditions.
avec les niveaux le plus eleve ay ant
lieu dans  la chair des predatores.
Le contenu de  cesium 137 dans les
tissues  des omnivores se  situent
entre celui des herbivores et des
predatores.   L'accroissement  de
concentration de cesium 137 dans les
niveaux trophiques  successifs est
en rapport avec la difference  de
la moitie de vie biologique du desium
et du potassium.   Du  fait que la
moitie de vie  biologique du cesium
est  environ trois fois plus grande
que celle du potassium, I'organisme
vient  a un etat sur  au niveau de
concentration  pour  le  cesium plus
grand que le niveau de la nourriture.
Le poisson de proie peut accumuler
10.000 fois plus  de  cesium  137
que  1'eau  et  une  comparaison de
facteur de  concentration par hectare
de produits d'animaux,  venant de
paturage et de  vivier  indique un
plus grand potentiel de chance pour
le dernier nomine.  La haute dis-
ponibilite  de  cesium  137  sur les
plantes  aquatiques  et  de  surface
indique  que  le lait et la viande
venant de  bovins  bubant de  1'eau
foree dans les marias peuvent con-
tenir  beaucoup plus de cesium 137
que les memes  produits venant de
paturages   normaux.   Aussi, les
variations  geographiques  observe
dans le pourcentage de cesium 137
dans le lait peut etre en partie un
resultat des niveaux differents d'ab-
sorption par les plantes de terrains
humides et sees.   Du fait que les
variations  du milieu cause de grande
difference dans 1'aptitude d'absorber
du cesium 137,1'e valuation du danger
pour  1'homme  a 1'encontre de cet
isotope  serait faite sur des regions
locales  plutot que  sur des regions
de base.   L'evaluation des dangers
ainsi presentee est  limitee  auxcon-
ditions d'eau douce.
trationen  werden  in  Fleisch  von
r^uberisch lebenden Tieren gefund-
en.  Der Caesium-137 Gehalt der
Gewebe von Omnivoren liegt  zwi-
schen dem der Herbivoren und  der
rauberisch  lebenden  Organismen.
Die stufenweise Zunahme der  Cae-
sium-137 Konzentration in den auf-
einanderfolgenden  ErnShrungsstu-
fenstehtmit dem Unterschied in den
biologischen Halbwertszeiten  von
Caesium und Kalium in Zusammen-
hang.   Weil  diese  Halbwertszeit
fiir Caesium ungefahr  dreimal so
lang wie  die  des Kaliums ist, so
kommt  ein Organismus bei hoheren
Verschmutzungen  durch  Caesium
Fruher  zum Gleichgewichtszustand
als der Gehalt an diesem Element in
seiner   Nahrung   andeuten  wiirde.
Raubfische konnen Caesium-137aus
Wasser auf das lOOOOfache anreich-
ern und ein Vergleich von Konzen-
trationsfaktoren und Ausbeute auf je
ein Hektar  an tierischen Produkten
von Weideland und Fischzucht weist
auf die letztere  als  die  grossere
mogliche  Gefahrenquelle bin.  Weil
Caesium-137  untergetauchten  und
teilweise  herausragenden Wasser-
pflanzen  leicht  zuganglich  ist,  so
ist zu  vermuten,  dass Milch und
Fleisch von Tieren, die auf feuch-
tem Land weiden, viel mehr  Cae-
sium-137 aus radioaktivem Ausfall
enthalten  als die gleichen Produkte
aus trockenen Weiden. Es ist mog-
lich, dass die geographischen Ver-
schiedenheiten  des   Caesium-137
Gehaltes  von Milch wenigstens zum
Teil auf  Unterschiede in der  Auf-
nahme  dieses  Elements   durch
Pflanzen auf feuchten und auf trok-
kenen Bbden zuriickgefuhrt  werden
konnen.  Da Umgebungsanderungen
grosse  Unterschiede in der  Cae-
sium-137  Aufnahme  verursachen
konnen, so sollten Auswertungen der
moglichen Gefahren von dieser Ele-
mentart  fiir  den  Menschen  auf
Grund   der ortlichen  Verhaltnisse
und  nicht  im Bezug  auf grosse
Flachenbereiche  gemacht  werden.
Die Gefahrenauswertungen des Vor-
tragenden beschranken sich auf die
Bedingungen in Siisswasser.
 THE EFFECTS OF STREAM SEDI-
 MENTATION ON TROUT EMBRYO
 SURVIVAL.   John Peters,   p. 275.
 Five sampling stations were estab-
 lished in Bluewater Creek to meas-
 ure  sediment  concentrations  and
 discharge.   In the vicinity of the
 sediment-discharge stations, man-
 made redds  were  constructed with
 sorted  gravel,  and eyed rainbow
 trout  eggs in hatching boxes were
 introduced into the redds. Periodi-
 cally,  the  Mark  VI   standpipe
 apparatus  was used   to  measure
 INFLUENCE DE  LA SEDIMENTA-
 TION EN RUISSEAU SUR LA SUR-
 VIVANCE   DES   EMBRYONS  DE
 TRUITES.   John  Pesters,  p. 275.
 Cinq stations de prelevement furent
 choisies  dans  la Bluewater Creek
 pour __ mesurer  les  concentrations
 en sediment et les  deversements.
 Au  voisinage^  des  deversements
 charges de  sediment, des frayeres
 artificielles furent amenagees avec
 des  graviers tries, et des  oeufs
 embryonnes de  truite arc-en-ciel,
 places dans  des boites a incubation,
 DIE   WIRKUNGEN DER  ABSET-
 ZUNGSVORGANGE IN   FLUSSEN
 AUF  DAS  UBERLEBEN VON FO-
 RELLENEMBRYONEN.       John
 Peters, p. 275.  Zum Zwecke  der
 Messung von  Bodensatzkonzentra-
 tionen und  Ablaufmenge wurden im
 Bluewater Creek fiinf Untersuchungs-
 stellen   gewahlt.  In ihrer Nahe
 wurden mit gesiebtem Kies Laich-
 platze errichtet und beaugte Regen-
 bogenforelleneier in KSsten an die-
 sen Statten ausgesetzt.   Von Zeit
 zu Zeit wurden mit dem Mark VI
                                                        412

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intragravel  dissolved  oxygen  and
intragravel apparent velocity within
the redds.  The  sampling stations
with low  sedimentation  rates  re-
sponded with high intragravel dis-
solved oxygen rates, high intragravel
seepage rates (apparent velocities),
and  low  trout embryo  mortality.
Conversely, the  sampling stations
with high  sediment rates responded
with low  intragravel dissolved
oxygen rates,  low intragravel see-
page  rates   (apparent velocities),
and high  trout embryo  mortality.
furent introduits sur ces frayeres.
Periodiquement, 1'appareil a colonne
ascendante Mark VI etait utilise pour
mesurer  1'oxygene  dissous et la
vitesse apparente dans les graviers
de la frayere. Les stations a faible
vitesse  de  sedimentation  corres-
pondaient a un taux  d'oxygene dis-
sous  eleve  dans les graviers,  a
une infiltration rapide (vitesse ap-
parente)  et a une faible mortalite
des embryons de  truite.  Inverse-
ment, les  stations   a  vitesse  de
sedimentation rapide corresponda-
ient a de faibles teneurs en oxygene
dissous  dans les graviers,  a une
infiltration  lente  et a  une forte
mortalite chez les embryons.
Standrohrgerat im Kiesbett Messun-
gen des gelosten Sauerstoffs und der
scheinbaren   Durchflussgeschwin-
digkeit in den Laichplatzengemacht.
An  Untersuchnungsstellen mit nie-
driger Absetzgeschwindigkeit wur-
den hohe Werte fur gelosten Sauer-
stoff, hone Sickerungsgeschwindig-
keit und niedrige Sterblichkeit  der
Forellenembryonen gefunden. Um-
gekehrt hatte hohe Absetzgeschwin-
digkeit  niedere Werte  fur gelosten
Sauerstoff,  niedere Sickerungsge-
schwindigkeit  (scheinbare Durch -
flussgeschwindigkeit)   und   hohe
Sterblichkeit der Forellenembryo-
nen zur Folge.
 ACCUMULATION   OF  RADIONU-
 CLIDES AND  THE EFFECTS OF
 RADIATION     ON    MOLLUSCS.
 Thomas J. Price.    p. 202 .  The
 accumulation  and  retention of
 cesium-137,  cerium-144   zinc-65,
 and gold-199  by  the  hard clam,
 Mercenaria mercenaria, by the bay
 scallop, Aequipecten irradians, and
 by the oyster, Crassostrea virginica,
 were determined in laboratory ex-
 periments.   Experiments with
 cesium-137 and cerium-144 were
 carried out with single species held
 in  separate holding containers. All
 of  these  animals concentrated
 cesium-137 over  the  amounts oc-
 curring in the  sea water.   A more
 rapid uptake was  found for the soft
 tissues other  than muscle.   The
 highest concentrations were reached
 in time, however, by muscle tissue.
 Uptake and loss of cesium-137 pro-
 ceeded  at different rates with time,
 being more rapid initially  followed
 by a slower  continued rate.  The
 accumulation of cerium-144 by
 clams and their  separated  shells
 indicates  that the physical  state of
 this isotope in sea  water is  an
 influencing factor.  Cerium-144
 occurs  mainly as particles in sea
 water  and  was taken up by the
 molluscs  directly  from the water
 or  obtained  from materials that
 had been  associated  with phyto-
 plankton.   This radionuclide was
 accumulated  by adsorption of the
 particles  to  body  surfaces  of the
 clam or by retention in the organs
 and structures  connected  with the
 digestive  tract.  The initial loss of
 cerium-144 by  clams  and  scallops
 was rapid followed by a reduced rate
 of loss.  After  195 days, 20 percent
 of the original cerium-144 remained
 in the  clams.  Of this, 11 percent
 was found in the visceral mass, 38
 percent in the  muscle, and 45 per-
 cent in the shell.  After 35 days,
 shells  of  scallops had lost 55 per-
ACCUMULATION  DES RADIONU-
CLIDES  ET  EFFETS DE  LA RA-
DIATION SUR LES MOLLUSQUES.
Thomas  J.  Price,   p. 202 .  On a
determine par des  essais  de  la-
boratoire 1'accumulation et la  re-
tention de cesium-137, de  cerium-
144, de  zinc-65, et d'or-199 chez
les  palourdes, Mercenaria  mer-
cenaria,  les  petoncles de baie,
Aequipecten irradians, etles huitres
Crassostrea  virginica.  Au cours
des experiences avec le cesium-137
et le cerium-144, on a utilise  des
contenants separes pour une espece
seule.   Tous ces animaux ont con-
centre le cesium-137 en quantites
plus grandes que cellesqu'ontrouve
dans 1'eau de  mer.   On a trouve
que  cette  accumulation est  plus
rapide dans les tissus mous, autres
que  les  muscles.   Toutefois, avec
le temps, les plus fortes  concen-
trations  ont  ete  atteintes  par les
tissus musculaires. L'accumulation
et la perte de  cesium-137 se pro-
duisent a des vitesses differentes
suivant le  temps;  au debut 11  y a
une phase rapide suivie d'une phase
plus lente   mais soutenue.  L'ac-
cumulation du  cerium-144 par les
palourdes et leurs coquilles
separees indique que 1'etat physique
de  cet isotope dans  1'eau de mer
est un facteur qui influence cette
accumulation.  Le cerium-144 se
presente  surtout  sous  forme  de
particule dans 1'eau de mer ou les
mollusques 1'ontprisdirectementou
bieu 1'ont obtenu  d'organismes qui
sont associes  au phytoplancton.
L'accumulation de  ce radionuclide
s'est fait par adsorption des par-
ticules a la surface exterieure des
palourdes ou par leur retention dans
les organes et  les  structures
associees au  systeme digestif.   La
perte de  cerium-144 par les pal-
ourdes et les petoncles est rapide
au  debut puis  ensuite plus  lente.
Apres  195 jours, il ne reste dans
ANREICHERUNG  VON RADIOAK-
TIVEN  ELEMENTEN UND 8TRAH-
LUNGSEINFLUSSE AUF MOLLUS-
KEN.   Thomas J. Price,  p. 202 .
Die  Anreicherung und Speicherung
von  Caesium-137,  Cer-144,  Zink-
65  und Gold-199  durch  die Ve-
nus muschel, Mer c enaria mere enaria,
die  Bucht -  Kammuschel, Aequip-
ecten irridans, und durch die Auster,
Crassostrea   virginica  wurde  in
Laboratoriumsversuchen bestimmt.
Die  Versuche mit Caesium-137 und
mit Cer-144 wurden mit jeweils ei-
ner  Art  in  getrennten Behaltern
durchgefuhrt.  Alle Tiere reicher-
ten Caesium-137 gegenuber den im
Meerwasser  vorkommenden   Be-
tragen an. Fur die Weichteile wurde
eine raschere Aufnahme festgestellt
als fur Muskelfleisch, letzteres er-
reichte  jedoch  mit  der Zeit die
hochsten  Konzentrationen.    Auf-
nahme und Verlust von Caesium-137
gingen  mit  verschiedenen    Ge-
schwindigkeitenvorsich: dieanfangs
rasche Aufnahme verlangsamte sich
und  ging schliesslich in die Abgabe
iiber.  Die Anreicherung von  Cer-
144  durch Muscheln und durch Mu-
schelschalen zeigte, dass der phy-
sikalische Zustand dieser  Atomart
im Meerwasser  von Einfluss ist.
Cer-144 ist im Meerwasser in festen
Teilchen zu finden; es wurde von den
Mollusken unmittelbar  aus  dem
Wasser aufgenommen Oder aus Stof-
fen  erhalten, die vorher an Phyto-
plankton gebunden  waren. Dieses
Radioelement wurde durch Adsorp-
tion der  Teilchen an Korperober-
flachen  der  Muschel oder durch
Speicherung  in den Verdauungsor-
ganen und im Verdauungskanal an-
gereichert.   Der anfSngliche  Ver-
lust der Venus - und der Kammu-
scheln an Cer-144 was anfangs be-
trachtlich und nahm dann ab.   Nach
195  Tagen waren nur noch 20  v. H.
des urspriinglich vorhandenen  Cer-
144  in  den  Muscheln  verblieben;
                                                       413

-------
cent of their initial activity, adductor
muscle,  62 percent,  and visceral
mass, 89 percent.

   The accumulation of zinc-65 and
gold-199 by clams, separated clam
shells,  and oysters  was followed
in  an  experimental  marine com-
munity  that  also  contained  fish,
crabs, and sediments. A comparison
of the uptake of zinc-65 by clams and
oysters revealed that after 21 days
oysters had accumulated the nuclide
approximately  8 times  over that
in  clams;  however,  there was no
indication that maximum levels of
zinc-65 had been reached in either
organism.  Live  clams removed 3.6
times more gold-199 than separated
clam shells.   Clams  that   had
burrowed in  montmorillonite clay
at the bottom  of the tank contained
38 percent less gold-199 than others
remaining  in  the radioactive  sea
water.

   Experiments are in progress to
determine  the effects of gamma
radiation from a high level cobalt-
60 source on shellfish. Preliminary
observations indicate  that clams are
more radiosensitive  than  oysters
to this radiation.
les palourdes  que 20% du cerium-
144 du  debut.   On  a trouve  11%
de  ce  cerium  dans  les visceres,
38% dans  le muscle, et 45% dans la
coquille.   Apres  35  jours,  les
coquilles de petoncles avaientperdu
55% de  leur  activite  initiale, le
muscle  adducteur 62%, et  les
visceres
   On a suivil'accumulationdu zinc-
65 et de l'or-199 chez les palourdes,
leurs  coquilles separees et chexles
huitres dans  un  habitat marin qui
comprenait aussi des poissons, des
crabes, et des sediments.  En com-
parant I'absorption du zinc-65 par
les palourdes et  par les huitres on
a trouvequ'apres 21 jours les huitres
avaient accumule  8 fois  plus  de
cette  substance que  les palourdes;
toutefois rien n'indique que les
niveaux maxima  de zinc-65 aient
ete atteints pour 1'unaul'autre. Les
palourdes  vivantes  absorbent 3.6
fois plus d'or-199 que les coquilles
seules. Les palourdes qui s'etaient
enfouies dans la glaise«montmoril-
lonite^ au  fond du reservoir con-
tenaient 38% moins d'or-199 que les
autres specimens qui etaient  restes
dans  1'eau  de  mer  radioactive.

   On  a entrepris des travaux pour
determiner 1'effet  de la radiation
gamma provenant d'une source
elevee de  cobalt-60 sur les^ mol-
lusques. Les observationsprelimi-
naires indiquent  que les palourdes
sont plus sensibles a cette radiation
que les huitres.
da von  war en  11 v. H. in der Ein-
geweidemasse, 38 v. H. im Muskel
und 45 v. H.  in der Schale.  Nach
35  Tagen  hatten  die  Schalen der
Kammuscheln 55  v.  H. ihrer ur-
spriinglichen  Aktivititat  verloren,
der  Schliessmuskel 62  v.  H. und
die Eingeweidemasse 89  v. H.

   Die  Anreicherung  von  Zink -
65 und von  Gold-199 durch Kamm-
muscheln,    Muschelschalen   und
durch  Austern  wurde  in   einer
marinen Versuchanlage, die auch
Fische,  Krabben   und  Sedimente
enthielt, untersucht.  EinVergleich
der Aufnahme von Zink  - 65 durch
Muscheln und Austern zeigte, dass
nach  21 Tagen die Austern etwa
achtmal mehr radioaktives Element
angereichert  hatten als die  Mu-
scheln; es war aber kein Anzeichen
dafiir vorhanden, dass in dem einen
oder   anderen   der  Organismen
Hochstwerte an Zink-65  erreicht
worden waren. Es wurde gefunden,
dass lebende Muscheln 3,6 mal mehr
Gold - 199  entfernten  als  die Mu-
schelschalen allein. Muscheln, die
sich in den Montmorillonitlehm am
Versuchsbehalterboden eingegraben
hatten, enthielten  38 v.  H. weniger
Gold  -  199  als  andere,  die  im
radioaktiven Meerwasser geblieben
waren.

   Versuche zur  Bestimmung der
Wirkung  starker  gamma  -Strah-
lung von Kobalt - 60 aufSchalen-
tiere  sind  im Gange.   Vorlaufige
Beobachtungen zeigen,  dass Mu-
scheln fur diese Strahlung empfind-
licher sind als Austern.
 RADIOACTIVITY IN FRESHWATER
 ORGANISMS OF THE  LAKES  OF
 NORTHERN ITALY. Oscar Ravera.
 p. 195. Samples of plankton, larger
 aquatic plants, fishes, benthos, mol-
 luscs,  and sediment  collected  in
 some lakes of northern Italy were
 examined  to compare their  radio-
 activity.  Manganese-54, a gamma
 emitting activation product, was
 found  in   the  soft  tissues  of  the
 lamellibranchs.   The radionuclide
 content is  very different  in popu-
 lations  settled in different zones of
 the same lake (Lake Maggiore). The
 highest level  of radioactivity was
 found in the sediment in which the
 total beta-activity was observed to
 increase with  increasing depth. The
 periphyton  always  showed  higher
 radioactivity values  than the aquatic
 plant jn which it lives. The season
 and  the  zone  have only a little
 influence  on  the  uptake  of  radio-
 activity  by plankton,  fish, and
 benthos, whereas  age  plays  a very
 important  role  in this process both
 in  the  mollusc and  in the fish.
 RADIOACTIVITE DES ORGANISMES
 D'EAU DOUCE  DANS LES LACS
 DU  NORD DE  L'lTALIE.   Oscar
 Ravera.  p. 195 .  Des echantillons
 de  plancton,  plantes  aquatiques
 superieures,poissons, benthos, mol-
 lusques et sediments recueillis dans
 quelques  lacs  du Nord  de 1'Italie
 furent examines pour comparer leur
 radioactivite.   Le  manganese  54,
 produit emetteur de  rayons gamma,
 fut trouve dans  les tissues  mous
 des  lamellibranches.  La teneur en
 radionuclide  est  tres   differente
 dans  les  populations etablies en
 divers points d'un meme lac  (Lac
 Majeur)0   La radioactivite  la  plus
 elevee fut trouvee  dans les  sedi-
 ments  et, dans  ceux-ci, 1'activite
 beta  totale augmente  avec  la pro-
 fondeur.   La periphyton presente
 toujours une r adioa cti vite plus
 elevee que les plantes superieures
 sur  lesquelles  il vit.    La saison
 et  la  situation  ont  peu  d'influence
 sur  la fixation de  la radioactivite
 par  le plancton,  le poisson et le
 benthos tandis  gue  1'Sge  joue un
 grand role dans  ce processus,  a
 la fois chez les mollusques et les
 poissons.
                414
 RADIOAKTIVITAT  IN   FRISCH-
 WASSERORGANISMEN DER NORD-
 ITALIENISCHEN   SEEN.    Oscar
 Ravera.     p. 195 .    Proben  von
 Plankton, grosserenWasserpflanzen,
 Fischen,  Benthos,  Mollusken und
 Sediment  aus einigen der nordita-
 lienischen   Seen wurden auf ihre
 Radioaktivitat untersucht  und die
 Ergebnisse verglichen. Der gamma-
 Strahler Mangan - 54 wurde in den
 Weichteilen der  Lamellibranchen
 gefunden.    Der  Gehalt an radio-
 aktiven Elementen indenBewohnern
 der verschiedenen Tiefenzonen ein
 und desseltaen Sees 1st sehr unter-
 schiedlich.  Htfchstwerte der Radio-
 aktivitat wurden im Sediment ge-
 funden; in  diesem zeigte sich mit
 zunehmender  Tiefe ein Ansteigen
 der Radioaktivitat. Das Periphyton
 hatte stets  hohere Werte der Radio-
 aktivitat als  die Wasserpflanzen,
 auf welchen es lebt. Jahreszeit und
 Zone  haben nur geringen  Einlluss
 auf die Aufnahme von Radioaktivitat
 durch Plankton,  Fische und Benthos,
 wahrend in Mollusken und  Fischen
 das Alter  in diesem Vbrgang eine
 sehr wichtige Rolle spielt.

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DIATOMS AND  THEIR  PHYSICO-
CHEMICAL    ENVIRONMENT.
Charles  W.  Reimer.  p.  19  .  In
the past 40 years considerable field
data have been gathered concerning
the physical and chemical factors
of the water in which certain diatoms
have been found.  Some of these data
have  been  worked  into key-word
series,  each series representing
some  factor  of the environment,
i.e.,pH series, acidobiont, acidophil,
indifferent,  alkaliphil, alkalibiont.

   Such  terms  have not received
wide  usage  in this country as re-
gards  the algae.  Indeed, at the
species  level little has  been done
here to indicate whether or not such
ecological amplitudes, be  they in
actual figures or in key-word series,
are generally applicable.

   In this study the following diatom
taxa are considered: Cymbella
tumida (Breb.)  V.H., Melosira
varians  Ag., Navicula confervacea
Ku'tz., Navicula  ingenua  Hust., and
Nitzschia amphibia Grun. The water
quality ranges and ecological cate-
gories applied to these diatoms by
other workers are compared to the
physico-chemical characteristics of
water  in which these diatoms have
been  found  in this country.   Data
used in this  compilation represent
59 sampling series from  8 different
rivers.

   In general, there is good agree-
ment between the literature reports
and our data for  these taxa.   In
many  cases  this is the first report
on certain chemical concentrations
relating to  these diatom  species;
e.g.,  this is the first report of the
chemical condition of the  water in
which the diatom, Navicula ingenua,
was found living.
DIATOMES  ET  LEUR  MILIEUX
AMBIANTS  PHYSICO-CHIMIQUES.
Charles W.  Reimer.^ p.  19 . Dans
les dernieres 40 annees, un numbre
considerable de  donnees  ont ete
recueilli  concernant les facteurs
chimiques et physiques de 1'eau dans
laquelle  certains diatomes ont ete
trouve. Quelques unes de ces donnees
ont ete  organist in series chaque
serie representant des  facteurs de
milieu  ambiant,  par exemple pH
serie, acidobiont,  acidophile, in-
different, alkaliphile, alkalibiont.
   De  tels  termes n'ont pas recu
un  large  usage dans  ce pays re-
lativement a 1'algue.  Evidemment,
relativement aux especes, peu a ete
fait  ici pour indiquer si de telles
amplitudes  ecologiques  etant dans
des  figures  actuelles ou dans des
classification, sont applicables.
   Dans  cette  etude  les  diatome
taxasuivants sont consideres: Cym-
bella tumida (Breb.) V. H.,Milosira
varians Ag., Navicula confervacea
Kiitz., Navicula  ingenua Hust., et
Nitzschia amphibia Grun.  Les do-
maines de_  qualite de 1'eau et de
cate"gorie ecologique appliques a ces
diatomes par d'autres travaux sont
compares aux  caracteristiques
physico-chimiques  de  1'eau  dans
laquelle ces diatomes ont ete trouve
dans ce pays. Les donnees utilisees
dans cette compilation representent
59 series d'echantillons  de 8  dif-
ferents fleuves.

   En  general  il  y a un bon agre-
ment entre  les rapports litteraires
et  notre  donnee  pour  ces taxa.
Dans beaucoup de cas, ceci  est le
premier rapport sur certaines con-
centrations  chimiques relative a ces
especes  de  diatomes, c'est-a-dire,
le premier rapport des conditions
chimiques  de  1'eau dans lequel le
diatome  Navicula  ingenua,  a ete
trouve vivant.
DIATOMEEN  UND  IHRE  PHYSI-
KALISCH - CHEMISCHE UMWELT.
Charles  W. Reimer.  p. 19  .  In
den verflossenen 40 Jahren wurde
eine grosse MengevonAngabenuber
die physikalischen und chemlschen
Eigenschaften des Wassers, in wel-
chem gewisse Diatomeen gefunden
wurden,  gesammelt.  Einige dieser
Werte wurden in Stichwortreihen an-
geordnet, wo jedeReiheeinenUmge-
bungsfaktor,  namlich  pH Stufen,
saurefest, acidophil, neutral, alka-
liphil,  alkalifest  darstellt.   Eine
solche Einteilung hat im Bezug auf
Algen  in den Vereinigten Staaten
bisher nur  begrenzte Anwendung
gefunden. Tatsachlich wurde beziig-
lich der Arten nur sehrweniggetan,
dass  es  schwer ist, festzustellen,
ob solche oekologische Eigenschaf-
ten, mb'gen sie in  Zahlen oder in
Stichwortreihen vorliegen,   allge-
mein anwendbar sind.

   In der vorliegenden Studie wurden
die folgenden Abteilungen von Dia-
tomeen  berucksichtigt:  Cymbella
tumida Brebisson, V. H., Melosira
varians  Agardh,  Navicula confer-
vacea  Kutzing,  Navicula  ingenua
Hustedt,  and  Nitzschia  amphibia
Grun,  Die Arten und oekologischen
Bereiche der Wassergiite,  welche
von anderen  Forschern auf diese
Diatomeen angewendet wurden, wer-
den mit  den  physikalisch - chemi-
schen Eigenschaften der Gewasser
verglichen, in welchen diese Dia-
tomeen  in den Vereinigten Staaten
gefunden wurden.  8 verschiedene
Flusse sind  in 59 Versuchsreihen
vertreten.

   Im allgemeinen ist  die  Uber-
einstimmung zwischen Literaturan-
gabenundunseren Feststellungengut.
Oft berichten wir als  die Ersten
uber  bestimmte chemische Bedin-
gungen des Wassers fur bestimmte
Diatomeenarten; dies ist zum Bei-
spiel fur Navicula  ingenua der Fall.
 ENVIRONMENTAL REQUIREMENTS
 OF  TRICHOPTERA.    Selwyn  S.
 Roback. p.118 .  Over many years,
 the  Limnology Department  of  the
 Academy of  Natural  Sciences  of
 Philadelphia has  conducted stream
 surveys at over  100 stations in the
 United States and Canada.  At any of
 these stations, the caddisfly larvae
 form about  10 percent of  the total
 insect fauna.  The ranges of occur-
 rence for each of 14 chemical factors
 are  given for the dominant genera,
 and  in some cases families  (where
 there  were  too  few  records)  of
 caddisfly larvae.    Too  few of  the
 larvae collected can be placed as to
 species with sufficient certainty to
 make  data  at the  species  level
CONDITION DU MILIEU AMBIANT
DE  TRICHOPTERA.     Selwyn S.
Roback.  p. 118 .  Depuis de nom-
breuses  annees  le Department
Limnologique   de  1'Academie de
Sciences Naturelles de Philadelphie
conduit 1'etude des courants d'eau
sur  plus  de  100 places aux  USA
et  au  Canada.   Dans  la  plupart
de    ces   stations,   les  larves
Trichoptera torment  entre les 10%
de la faune insecte.  Les domaines
de fait pour chacun des 14 facteurs
chimiques  sont donnes par  la gen-
eration dominante,  et dans des cas
de famille  (ou il y avait trop peu
de  rapports)  par les larves
Trichoptera.   Trop  peu de  ces
larves collectees peuvent etreplace,
               415
 DIE  ANFORDERUNGEN DER TRI-
 CHOPTEREN ANIHRE UMGEBUNG.
 Selwyn  S. Roback.   p. 118.  Viele
 Jahre lang hat das Limnology De-
 partment of the Academy of Natural
 Sciences of Philadelphia Untersuch-
 ungen an Fliissen an uber 100 Ver-
 suchsstellen   in  den  Vereinigten
 Staaten und in Kanada durchgefuhrt.
 An  alien diesen  Orten bilden die
 Eintagsfliegenlarven etwa 10% der
 Insektenfauna.  Die Bereiche  des
 Vorkommens fur jedeneinzelnenvon
 14 chemischen Faktoren werden fur
 die  vorherrschenden Gattungen und
 in einigen Fallen fur die  Familien
 (wennnicht genugend Aufzeichnungen
 vorhanden waren) von Eintagsflie-
 genlarven gegeben.  Zu wenige der

-------
meaningful.  Labo ratory experi-
ments  on the toxicity of various
chemicals to  caddisfly larvae are
practically non-existent;  however,
the results  of one  set of experi-
ments  performed  at the  Academy
are presented.
avec suffisamment de surete, quant,
a  fam'ille.   D8s  experiences  de
laboratoire sur  la toxiquite  rte dif-
ferents  produits  chimiques  sjr les
larves Trichoptera,  sont pratique-
ment inconnues.    Cependant  les
resultats d'un groupe d'experience
fait  a 1'academie, sont presentes.
gesammelten  Larven  konnen  mit
genligender  Sicherheit einer  be-
stimmten Gattung  zugeordnet wer-
den, sodass Gattungsangaben nicht
hinreichend zuverlassig sind.  La-
boratoriumsversuche bezuglich der
Giftigkeit verschiedenerchemischer
Stoffe  gegenuber   Eintagsfliegen-
larven gibt es praktisch nicht; in-
dessen werden die Ergebnisse einer
einzigen Versuchsreihe, welche an
der  Akademie  ausgefuhrt  wurde,
mitgeteilt.
THE  APPLICATION OF DIATOM
ECOLOGY AND  PHYSIOLOGY TO
PROBLEMS  OF   WATER   POL-
LUTION AND PURIFICATION. F.E.
Round,   p.  29.  The distribution
of diatoms over  the  range  of pol-
luted water is discussed as well as
their relation  to standards of un-
polluted natural waters. A suggested
widening of the scope of studies of
diatoms in polluted waters to include
the flora of the individual habitats
is outlined and the data compared
with  experimental  methods of as-
sessing pollution.    The classifi-
cation of the habitats and the methods
of sampling are discussed. The basic
ecological  requirements  of diatoms
and  the modification of these in
polluted waters are detailed. Prob-
able mode of action of pollutants on
diatoms and the beneficial effects
of the diatom flora in self-purifi-
cation of  polluted waters are dis-
cussed.  Detection of incipient pol-
lution from a study of lake sediments
involving indicator  species  and the
need for a re-evaluation of indicator
species are argued.
APPLICATION DE L'ECOLOGIE ET
DE LA^PHYSIOLOGIE^  DES DI-
ATOMEES AUX PROBLEMES DE
POLLUTION ETDE PURIFICATION
DE L'EAU.  F.E. Round,  p.  29.
On a  etudie  la  distribution  des
diatomees  dans plusieurs  eaux
polluees  et  aussi leur rapport avec
les types observes dans des eaux
naturelles  non polluees.   Ony
suggere un plan d'etude plus etendu
des diatomees en  eaux  polluees et
on  y  compare aussi les resultats
obtenus  par differentes methodes
devaluation  de la pollution.   La
classification  des  milieux et les
methodes d'echantillonnage font le
sujet d'une discussion.  ^Ony etudie
en details les exigences ecologiques
fondamentales des diatomees et
leurs modifications en eaux polluees.
On y indique aussi la  maniere
probable d'agir des polluants sur
les diatomees  et  les  effets salu-
taires  de la flore des diatomees
sur la purification subsequente des
eaux  polluees.   On y  discute la
mise  en evidence  de  la pollution
naissante d'apres  une  etude des
sediments  de lacs basee  sur des
especes  indicatrices  et aussi le
besoin de faire une nauvelle evalu-
ation  de ces especes indicatrices.
DIE  ANWENDUNG  VON  DIATO-
MEENOEKOLOGIE  UNO  PHYSI-
OLOGIE AUF FRAGEN DER WAS-
SERVERUNREINIGUNG UND   REI-
NIGUNG. Frank Eric Round, p.  29 .
Die Verteilung von Diatomeen liber
die  verschiedenen  verunreinigten
Wasser  und  ihre Beziehungen zu
Normen nicht verunreinigter natu'r-
licher Wasser wirdbesprochen. Ein
vorgeschlagenes weiteres Feld von
Diatomeenstudien  in verunreinigten
Wassern dur ch Einschluss der Flora
der einzelnen Vorkommen wird im
Umriss beschrieben unddieErgeb-
bniss*  mit  experimentellenMetho-
den   der Schatzung von  Verunrei-
nigung  verglichen.  Die  Einteilung
der Vorkommen,  Probenahmever-
fahren,  grundlegende  oekologische
Erfordernisse  der Diatomeen und
deren Veranderung in verunreinig-
ten Wassern werden besprochen.
Die wahrscheinliche Form, in wel-
cher  die Verunreinigungen auf die
Diatomeen  einwirken und     die
vorteilhaften Auswirkungen der Dia-
tomeenflora in der Selbstreinigung
verschmutzter  Wasser wird ero'r-
tert.  Entdeckung beginnender Ver-
unreinigung durch das Studium von
Ablagerungen in Seen mittels Leit-
organismen und die  Notwendigkeit
erneuter Auswertung von   Leitorga-
nismenarten werden vorgeschlagen.
 THE  CONTROL  OF  BACTERIAL
 AND VIRUS DISEASES OF FISHES.
 S.  F. Snieszko. p. 281.  To conduct
 bioassays  with a  satisfactory level
 of  reproducibility, it  is necessary
 to  have test fish of uniform quality.
 Parasitic,  bacterial and viral dis-
 eases,  malnutrition, and uncertain
 hereditary  background can drasti-
 cally affect the  usefulness of the
 fish used for bioassays. Methods of
 control  of bacterial and viral fish
 diseases with drugs  such as sul-
 fonamides and nitrofurans, with anti-
 biotics such as chloramphenicol and
 tetracyclines, with chemical disin-
 fectants, by immunization, by breed -
 LE  CONTROLS  DES MALADIES
 DES  POISSONS  PAR BACTERIES
 ET VIRUS.  S. F. Snieszko. p. 281.
 Pour  conduire  ces  tests avec un
 niveau satisfaisant de production, il
 est necessaire de tester des poissons
 de qualite uniforme. Les maladies
 parasitiques, bacteriologiques
 et virulentes, la malnutrition,  la
 connaissance d'une  incertaine
 her^dite* peuvent  affecter  regoureu-
 sement 1'entiere utilite du poisson
 utilise pour les  essais biologiques.
 Les  methodes de  controle des
 maladies de poissons par bacteries
 et virus  avec des  drogues  telles
 que solfonamides, et nitrofurannes,
 DIE KONTROLLEVONBAKTERIEN
 - UNDVIRUSERKRANKUNGENVON
 FISCHEN.  S. F. Snieszko. p. 281.
 Um biologische Versuche miteinem
 zufriedenstellenden Grad von Wie-
 derholbarkeit durchzufuhren, ben8-
 tigt  man  Versuchsfische  einheit-
 licher  Gute.   Parasiten -, Bak-
 terien -  und   Viruserkrankungen,
 falsche  ErnShrung und  ungewisse
 Angaben fiber  VererbungkSnnendie
 Nutzlichkeit der Fische fur   biolo-
 gische Versuche drastisch  beein-
 flussen.    Kontrollmethoden   fur
 Bakterien  - und Viruserkrankungen
 der  Fische mit Drogen wie Sul-
 fanilamiden und Nitrofuranen,  mit
                                                        416

-------
ing of disease resitant  strains of
fish,  and by  means  of  general
sanitary measures are outlined.
 avec des  antibiotiques  tels  que
 chloramphenical  et  tetracyclmes,
 avec des disinfectants chimiques,
 par  immunisation et par  moyen de
 mesures sanitaires  generates, sont
 ebauchees.
Antibiotika wie Chloramphenikolund
Tetrazyklin,  mit chemischen keim-
totenden Mitteln, durch Immunisa-
tion,  durch   Zuchten von   gegen
Krankheit widerstandsfahigen Arten
von  Fischen und durch allgemeine
Gesundheitsmassnahmen    werden
dargelegt.
EFFECTS  OF  SUBLETHAL CON-
CENTRATIONS   OF  ZINC  AND
COPPER  ON  MIGRATION OF
ATLANTIC SALMON. J. B. Sprague.
p. 332 .   In  1960,  the  spawning
migration of adult  salmon in the
northwest  Miramichi  River, New
Brunswick, Canada,  was disturbed.
Of the salmon that moved upstream
during the warm season, 22 percent
came  back downstream through a
counting fence.  In the previous six
years, downstream movements had
usually been less than 2 per cent and
had  not exceeded 3 percent.   The
apparent cause was  sublethal con-
centrations of zinc and copper in the
river as a result of increased activity
at the base-metal mine during 1960.
Waste treatment at the mine in 1961
improved conditions somewhat, but
downstream movement was still 14
percent.   Disturbed migration
occurred on days whenpoliutio.iwas
high  as happened during fresnets.

   Efforts  to  pinpoint the "safe"
level of pollution for salmon migra-
tion  were complicated by the pres-
ence  of both  zinc and copper, each
varying somewhat independently of
the other.  Furthermore, it seemed
likely that seasonal changes in water
hardness  would modify the "safe"
level, similar to the way hardness
changes lethal  levels.   A  single
index of effective pollution was ob-
tained by using a system developed
at the  British Water Pollution
Laboratory.  From the water hard-
ness  in the  Miramichi  each day,
the threshold lethal  concentrations
for zinc and  for  copper were esti-
mated on the  basis  of laboratory
work. Then for each day, the actual
concentrations  of zinc  and copper
in the  Miramichi were expressed
as  fractions  of  their  respective
lethal thresholds.  The two fractions
for  each day were  added together
yielding a single "toxicity index."
Sharp variations of this index during
1961 corresponded  well  with dis
turbances of salmon migration.  A
"toxicity index" of 0.15 (15 percent
of the threshold lethal concentration)
seemed to be the maximum "safe"
level  for  salmon  migration.   A
 EFFETS  DES CONCENTRATIONS
 NON FATALES  DE  ZINC  ET DE
 CUIVRE SUR  LA MIGRATION DU
 SAUMON DE L'ATLANTIQUE. J.B.
 Sprague.    p. 332 .   En 1960,  la
 migration de ponte du saumon adulte
 a ete derangee dans  la partie nord
 ouest  de  la   rivier   Miramichi,
 Nouveau-Brunswick,  Canada.     A
 1'aide d'un barrage pour le comptage,
 nous avons observe  que 22% des
 saumons  qui avaient  monte  la
 riviere durant  la saison chaude
 etaient revenus en aval. Durant les
 six  annees  precedentes,  les de-
 placements avaient  ete ordinaire-
 ment de 1'ordre de  2%  ou moins
 et  jamais   au dessus de 3%.   II
 semble que la cause  de ce change-
 ment etait des concentrations
 elevees mais non fatales de zinc  et
 de  cuivre dans la riviere, concen-
 trations resultant (I'une plus grande
 activite a la mine des metaux lourds
 en 1960. En 1961, le traitementdes
 dechets  a  la  mine a ameliore un
 peu les conditions, mais ledeplace-
 ment en aval  etait  encore de 14%.
 La migration a ete derangee durant
 les joui=! ou la pollution etait elevee,
 comme  i;  arrivait durant la crue.

   Les travaux pour determiner  le
 degre de pollution qui ne serait pas
 nuisible a  la migration du saumon
 etaient compliques  par la presence
 de deux metaux, le zinc etle cuivre,
 dont les concentrations varient un
peu independamment 1'un de 1'autre.
De plus il semble vraisemblable que
 les changements  saisonniers de  la
durete de  1'eau  puissent modifier
 le niveau  'non  miisible'^ comme
d'ailleaurs   la durete  change les
 niveaux fatals.   Un seul  indice de
 pollution efficace a ete obtenu en
 utilisant un  systeme developpe au
 Laboratoire des  Recherches sur  la
 pollution de 1'eau, Angleterre.

   A partir de  la  durete de  1'eau
 de  la  riviere Miramichi  a  chaque
 jour, on a pu estimer au labora-
 toire les seuils des concentrations
 fatales  pour  le  zinc  et pour  le
 cuivre.  Ensuite  pour chaque jour,
 on  a  exprime' les concentrations
 actuelles de  zinc et de cuivre dans
EINFLUSS  VON  SUBLETHALEN
KONZENTRATIONEN  VON  ZINK
UND  KUPFER AUF DIE WANDE-
RUNG DES ATLANTISCHEN LACH-
SES.      J.  B. Sprague.  p. 332 .
Im  Jahre  1960 war  die  Laich-
wanderungdes erwachsenen Lachses
im  nordwestlichen    Miramichi -
Fluss, New Brunswick, Canada un-
regelmassig.   22 % des Lachses,
der  w'ahrend  der  warmen Jahres-
zeit stromaufwarts gewandert war,
kam durch den Zahlzaun stromab-
warts zuruck.  In den vorausgegan-
genen  sechs Jahren waren solche
Stromabwartswanderungen gewbhn-
lich unter 2 % und  hatten nie  3 %
iiberschritten,,  Anscheinend waren
sublethale Konzentrationen von Zink
und  Kupfer im Fluss als Folge der
vermehrten Tatigkeit eines Metall-
bergwerks w'ahrend des Jahres 1960
die Ursache.  Abwasserbehandlung
am  Bergwerk  selbst  w'ahrend des
Jahres 1961 bessertedie Lage etwas,
aber  die  Stromabwartswanderung
war immer  noch  14  %.  Die un-
regelm'assige Wanderung  fand  an
Tagen hoher Wasserverunreinigung,
z. B. wahrend Uberschwemmungen,
statt.

   Die Bem'uhungen,  eine ,,unschad-
liche" Hone der Verunreinigung fur
Lachswanderung zu  finden, waren
dadurch  erschwert, dass zwei Me-
talle vorhanden waren,   deren Kon-
zentrationen  sich  unabhangig von-
einander  anderten.     Ausserdem
schien   es  wahrscheinlich,   dass
zeitliche  Anderungen der Wasser-
harte die.,unschadliche" Hone beein-
flussen  wu'rden,  ahnlich wie  die
Harte die  tddliche  Konzentration
andert.   Ein einziges Merkmal der
tatsachlichen Verunreinigung wurde
erhalten, wenn ein System, das am
British Water Pollution Laboratory
entwickelt  worden  war,  benutzt
wurde.

   Auf Grund der  Wasserharte im
Miramichi - Fluss wurden taglich
die Schwellenwerte  der  tSdlichen
Konzentrationen fur  Zink  und  fiir
Kupfer im Laboratorium bestimmt.
Sodann wurden fur jeden Tag die im
Miramichi  gefundenen  Konzentra-
                                                       417

-------
consistent correlation with salmon
movements was  not obtained if any
of the three factors, zinc, copper,
or  water hardness, was ignored.
la riviere Miramichi comme frac-
tions  de  leurs  seuils fatals  re-
spectifs. Les  deux  fractions ont ete
additionnees pour chaque jour et on
a alors obtenu un seul ^indice de
toxicite^   Des variations tres
marquees de  cet  indice  en 1961,
correspondaient   bien   avec  les
changements  de  la   migration  du
saumon.  Un ^indice de toxicite^
de  0.15 (15%  du seuil des  con-
centrations fatales) semble 
-------
other causes.  The significance of
Chi Square values could have been
reduced by decomposition products
of algal  or vegetation decay, pol-
lution from the few ducks inhabiting
the pond,  etc., but the data showed
these  factors  to  be unimportant.

   When the over-all season's re-
sults  were  analyzed  for   livebox
fish  from Oeder Lake,  combining
slightly objectionable and  strongly
objectionable  as objectionable  in
both Oeder  Lake  and the  Control
Pond, a significant difference,  Chi
Square 4.425, was observed for fish
fried  in vegetable oil and  cracker
crumbs (Chi Square at probability
0.05 for one  degree of  freedom =
3.841).  For  those baked in alumi-
num foil,  the significance was even
greater,  12.74.  In Eggerding Pond,
where  outboard motors  were  op-
erated a  known length of time,
fish became tainted within  a month.
An outbreakoiCytophaga columnaris
then  killed   all livebox fish,  but
tasting  of other fish outside the
boxes was carried out, as well as
later tasting of livebox-confined fish,
which again became tainted within a
month.   When the  Chi Square test
for significance was  applied to  all
portions  of bluegills fried  from the
beginning of  panel  sessions with
Eggerding Pond bluegills, a high
value of  20.8 was obtained. Baking
produced  even  more  striking re-
sults with a  high Chi  Square value
of 22.67.
 legerement desagreable et + = gout
 ire's desagreable.

    Les resultats furent  analyses au
 test  (X2)  avec 1'hypothese que les
 poissons  de  1'etang  de  controle
 pouvaient  egalement  etre alteres
 par des causes naturellesouautres.
 La signification des valeure de  X^_
 auraient pu  etre reduite  par des
 produits de decomposition des algues
 ou des vegetaux par une  pollution
 due aux canards habitants 1'etang
 etc ....  mais  les resultats   ont
 montre que  ces facteurs  n'etaient
 pas importants.

   Quand  les resultats de toute  la
 saison  furent  analyses pour  les
 poissons du Lac Oeder en combinant
 les^iegerement desagreables^et les
<<;tres  desagreables^  en un seul
 groupe ^desagreable-* a la fois pour
 le lac Oeder  et pour 1'etang de con-
 troles,  une difference significative
 (X2 = 4,425) _fut observee pour les
 poissons panes  (X2 pour 1 degre
 de liberte et une probabilite de  0,05
 = 3,841).   Pour  ceux  cults  dans
 1'aluminium,  la  signification  £tait
 encore  plus grande : 12,74.  Dans
 1'etang d'Eggerding ou leshorsbord
 ne circulaient que pendant des temps
 donnes, les poissons furent alteres
 en 1 mois.  Un developpement brutal
 de Cytophaga columnaris tuaitalors
 tous les poissons dans  les nasses
 mais  la  degustation  d'autres
poissons,  exterieurs  aux nasses,
fut poursuivie  ainsi que  celle de
 nouveaux  poissons  enfermes  qui,
 cette  fois  encore,  s'altererent en
un  mois.   Quand  le test X2  fut
applique a toutes  les  portions de
poisso,1 frits  depuis le debut des
experiences  avec les  bluegills de
1'etand d'Eggerding, la valeur elevee
de  20,8 fut obtenue.   La cuisson
dans 1'aluminium donnait  des  re-
sultats  encore  plus  frappants  avec
la valeur de X2 - 22.67.
195°  C in der  Pfanne auf beiden
Seiten gebraten,  Oder  20  Minuten
lang  in Aluminiumfolie eingeschla-
gen  bei  350°  F  oder etwa 175°
C gebacken.  Den Versuchsteilneh-
mernwurdenachjeder Geschmacks-
probe   kalte Milch zum  Trinken
vorgesetzt.  Der Geschmack jeder
Fischprobe wurde auf Karten durch
3 verschiedene Zeichenausgedriickt;
0  =  einwandfrei,  -  = nicht  ganz
einwandfrei,  und + = stark uner-
wiinschter Geschmack.  Die Ergeb-
nisse wurden durch die X2 Analyse
gepriift  unter der  Annahme,  dass
Geschmacksveranderungen    des
Fischfleisches im Vergleichsweiher
durch natiirliche oder  andere  Ur-
sachen  ebenso  moglich  gewesen
waren wie in den anderen zwei Wei-
hern.  Die Bedeutung der X2 Werte
h'atte durch  Zersetzungsstoffe von
Algen   oder  anderen  pflanzlichen
Stoffen, durch Verunreinigungdurch
einige Enten in  dem  Weiher usw.
herabgesetzt werden  kbnnen;  die
Ergebnisse  zeigten indessen, dass
diese Einfliisse unbedeutend waren.

   Fur  die Analyse der Ergebnisse
einer Versuchsreihe an Fischenaus
den Hasten vom Oeder Lake wurden
die - und die + Werte dieses Weiher s
und des Vergleichsweihers als nicht
einwandfrei  zusammengefasst und
ergaben  einen  deutlichen  Unter-
schied,   X2  =  4,425,  flir die  in
Pflanzenol mit Semmelbrbseln ge-
bratenen  Fische (X2  = 3,841 fur
einen Fr eiheitsgr ad bei Wahr schein-
lichkeit 0,05).    Fur die in Alumi-
niumfolie  gebackenen  Fische war
der Unterschiedsogar noch grosser,
namlich 12,74. ImEggerdingweiher,
wo  Aussenbordmotore einebekannte
Zeitlang  benutzt wurden,  war eine
Geschmacksverschlechterung   des
Fischfleisches innerhalb eines  Mo-
nats eingetreten.  Ein Ausbruch von
Cytophaga columnaris  totete  dann
alle Fische in den Hasten, jedoch
wurden    die   freischwimmenden
Fische der Geschmacksprobeunter-
worfen; spater wurden wiederum in
Kasten  gehaltene  Fische  geprlift:
sie  waren  ebenfalls  nach einem
Monat  wieder  nicht  einwandfrei.
Wenn die  X2 Probe auf alle Proben
von  Bluegills angewandt wurde, die
vom Versuchsbeginn an dem Egger-
dingweiher entnommen worden wa-
ren, dann erhielt man einen hohen
Wert von  20,8.  Backen gab sogar
den  viel hoheren Wert von 22,67.
                                                        419

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EUTROPHICATION OF LAKES AND
RIVERS.  E. A. Thomas,  p. 299.
A plentiful supply of fertilizers
reaches  algae  and higher aquatic
plants in rivers and lakes by means
of  sewage, even when the sewage is
mechanically and biologically puri-
fied. Nitrates and phosphates, which
are particularly important as fertili-
zers, stimulate the growth of algae
and higher aquatic plants; this leads
to  manifold damages  and compli-
cations.  The direct measure against
the eutrophication of rivers and lakes
that  promises the  greatest success
is  the thorough removal of  phos-
phates  from the  sewage.   If  the
sewage from industrial plants is rich
in phosphates, the phosphates should
be removed, where possible, within
the plant, or  such  sewage should
be used  for agricultural purposes.
Reference is made to some further
aids to  prevent eutrophication of
lakes and  rivers.   The special
limnological character of  each type
of  sewage must be especially con-
sidered  when choosing preventive
measures.
EUTROPHICATIONS DES LACS ET
RIVIERES.  E. A. Thomas, p. 299.
Une alimentation complete de fer-
tilisants  s'etends  aux algues  et
hautes plantes aquatiques enfleuves
et lacs, aumoyend'egouttage, meme
quand celui-ci est mecaniquement
et biologiquement  purifie.    Les
nitrates et phosphates qui sont par-
ticulierement  importants  comme
engrais  stimule la croissance des
algues et  des  haute   plantes
aquatiques.

   La mesure directe contre  1'eu-
trophication des rivieres et lacs qui
promet  le plus grand  succls est
Pelimination  complete  des  phos-
phates des eaux d'egout. Si 1'egout
provenant d'usines industrielles est
riche en  phosphate,  le phosphate
doit  etre elimine, si  possible dans
1'usine meme ou  de tels  dechets
seraient utilises £ des fins agricoles.
La  recommendation est faite pour
d'autres  aides  additives  afin  de
prevenir   1'eutrophication des
rivieres  et  lacs.    Le caractere
speciale limnologique de chaque type
d'eaud'egout,doit etre specialement
considere quand des  mesures pre-
ventives sont prises.
EUTROPHIKATION VON SEENUND
FLUSSEN.  fE. A. Thomas, p. 299 .
Algen und hohere Wasserpflanzenin
Fliissen  und  Seen  erhalten   eine
reiche  Zufuhr  von  Dungemitteln
durch  Abwasser, auch wenn diese
mechanisch und biologischgereinigt
wurden.    Nitrate und  Phosphate,
welche  als  Dungemittel besonders
wichtig sind, reizen das Wachstum
von Algen und hoheren Wasserpflan-
zen; diese Tatsache fuhrt zu mannig-
fachen Schadigungen und Schwierig-
keiten. Die unmittelbare Massnahme
gegen   diese  Eutrophikation   von
Flussen  und Seen,  welche   den
grossten Erfolg  verspricht, ist die
grundliche   Entfernung  von Phos-
phaten aus den  Abwassern.  Wenn
die Abwasser von industriellen Un-
ternehmen  phosphatreich sind, dann
sollten die Phosphate moglichst  in
der  Fabrik selbst entfernt werden
oder die Abwasser sollten fur land-
wirtschaftliche  Zwecke verwendet
werden.    Einige weitere Abhilfen
gegen  die  Eutrophikation  von Seen
und  Flussen werden erwahnt. Der
limnologische Charakter  des Ab-
wassers muss jeweils besonders  in
Betracht  gezogen  werden,   wenn
Vorbeugungsmassnahmen   gewahlt
werden.
 EFFECTS OF  COOLING WATER
 FROM STEAM-ELECTRIC POWER
 PLANTS ON  STREAM BIOTA.  F.J.
 Trembley.  p. 334.  The generation
 of  electricity   by  steam-electric
 stations  requires the use of large
 amounts  of  water  as  a coolant.
 This  necessitates the  release of
 heated water into rivers, lakes, and
 estuaries. The demand for electric
 power in the United States is in-
 creasing  by  about 10 percent an-
 nually.    Thus  the problem of re-
 lease  of  heated water  is  rapidly
 becoming acute.  Laws and regu-
 lations concerning such releases are
 often vague  and unrealistic or in
 many  states are  non-existent.  A
 brief account of research done in
 Pennsylvania, and observations
 made in  England  are given.  Sug-
 gestions are made for planning re-
 search  in this  field, and an  im-
 proved  communication  system for
 research  findings is suggested.
 EFFETSDE L'EAUDEREFRIGER-
 ATION DE CENTRALES THERMI-
 QUES  SUR LES COURANTS D'EAU.
 F. J. Trembley. p. 334. La generation
 de  1'electricite par  centrales
 thermiques necessite,  comme re-
 frigerant, une grande quantite d'eau.
 Ceci necessite  par consequent, le
 rejet,  de  1'eau chaude utilisee dans
 les fleuves, lacs et estuaires.  La
 demande  en  electricite  aux USA
 s'accroit  generalement de dix pour
 cent par an.  Aussi le probleme du
 rejet de 1'eau  chaude est rapidement
 venu aigu.  Les  lois concernant de
 tels rejets sont  souvent vagues et
 inrealistes ou dans  certain etats,
 non existants. Debrevesrecherches
 en Pennsylvania et des observations
 faites  en  Angleterre ontet£donnas.
 Des suggestions sont  faites pour
 planifier  les  recherches  dans  ce
 domaine  et un  systeme  de com-
 munication  pour  des  recherches
 ayant abouti, est suggere.
 WIRKUNGEN DES KUHLWASSERS
 VON DAMPFKRAFTWERKEN  AUF
 DIE LEBEWELT IN  FLUSSEN.  F.
 J.  Trembley.  p. 334 . Die Erzeu-
 gung  elektrischer Energie durch
 Dampfkraftwerke erfordert grosse
 Kuhlwassermengen und diese  wie-
 derum verursacht das Einleiten von
 warmem Wasser inFliisse, Seen und
 Flussmiindungen.   Die Nachfrage
 nach elektrischer Energie  nimmt in
 den Vereinigten Staaten jahrlich um
 etwa 10 %  zu, sodass das Problem
 der Beseitigung  des  warmen Was-
 sers rasch kritisch wird. Die Ge-
 setze und Vorschriften, die sichmit
 solchen Entleerungen befassen, sind
 oft  unklar  und wirklichkeitsfremd
 oder in manchen Staaten liberhaupt
 nicht vorhanden.  Einkurzer Bericht
 iiber  Studien  in    Pennsylvanien
 und Beobachtungen in England wer-
 den gegeben. Anregungen zur  Pla-
 nung  von   Forschungsarbeiten auf
 diesem  Gebiet werden gemacht und
 ein verbesserter Plan zur Mitteilung
 der  Forschungsergebnisse    wire
 vorgeschlagen.
                                                       420

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TOXICITY OF SOME HERBICIDES,
INSECTICIDES,  AND INDUSTRIAL
WASTES.  P. Vivier and M. Nisbet.
p. 167 .    Toxicity  of  herbicides:
In the laboratory as well as in the
field, our bioassays with Simazine
and Atrazine have shown that these
products are greatly toxic when in
water, but are harmless to certain
plants that immediately absorb them.
Weedex, Weedazol, etc., are gener-
ally  less injurious, even at concen-
trations much higher than the normal
dose employed.

   Toxicity of copper sulfate: Long-
term studies of a small stream by
L. Mazoit,  et  al., showed that in
6 days 75  percent of the carp and
tench are killed by a 0.2 ppm con-
centration  of copper.  Most of the
minnows are also killed, but some
of them  can tolerate 0.3 ppm.  In
the nutritive fauna, larvae of Ep-
hemeropterae are killed, but those of
Trichopterae live but  seem to be
excited.   The water of this stream
was hard.

   Toxicity of synthetic detergents:
The  studies of J. Wurtz-Arlet have
shown that the anionic and non-ionic
detergents are  toxic for the eggs
and young brown trout (Salmo fario)
and  young  rainbow trout  (Salmo
gairdneri).   The  24-hour TLm is
3  to  5 ppm for the rainbow trout,
depending on the age of the fishes;
these quantities are lethal for the
young brown trout, however, in less
than 10 hours.

   Toxicity of sodium chloride bio-
assays  were performed  by P.
Laurent  on  numerous   aquatic
animals  with  a sodium  chloride
solution  of  10,000  ppm.      The
cyprinids resisted for 10 to 60 days,
according  to the temperature.  The
nutritive  faunas  (Asellus, Hydro -
psyche,Dreissensia, Sphaerium) are
more  sensitive;  50 percent were
decimated in from 2 to 6  days, as
were also the most current plants
found  in the stream  (Gallitriche,
Melosciadium, and Oenanthe).
 TOXICITE  DE  QUELQUES  HER-
 BICIDES, INSECTICIDES ET  EAUX
 INDUSTRIELLES.   P. Vivier  and
 M. Nisbet. p. 167.  Toxicite d'her-
 bicides: au  laboratoire aussi bien
 que sur le terrain, nos tests 'avec
 la Simazine et 1'Atrazine ont montre
 que cesproduits etaient trlstoxiques
 a 1'etat dissous  dans 1'eau, mais
 beaucoup moins  dangereux  s'il  y
 a des  plantes superieures qui les
 absorbent  rapidement.    Weedex,
 Weedazol, etc .  . . sont  generale-
 ment  moins  nocifs,  meme a  des
 concentrations tres superieures aux
 doses normales d'emploi.

    Toxicite  du Sulfate de  Cuivre:
 des etudes a long terme effectuees
 dan un petit ruisseaupar L. MAZOIT
 et  Coll. ont  montre qu'en 6 jours,
 75% des carpes  et tanches etaient
 tuees  par une concentration de 0,2
 ppm  de cuivre.    La  plupart  des
 vairons etaient tues egalement, mais
 quelques  uns  toleraient  0,3  ppm.
 Parmi la faune nutritive, les larves
 d'Ephemeroptera etaient tuees, mais
 celles de Trichoptera resistaient et
 semblaient  excitees.   L'eau  de ce
 ruisseau etait dure.

    Toxicite des detergents syntheti-
 ques: les etudes de .LWURTZkARLET
 ont montre que les detergents anioni-
 ques  et non-ioniques sont toxiques
 pour  les oeufs  et les alevins  des
 truites fario (Salmo fario) et les
 alevins  de   truites  arc-en-ciel
 (Salmo gairdneri). La concentration
correspondante a une tolerance limite
 moyenne de  24 h. est de  3 a 5 ppm
 pour   la truite   arc-en-ciel  selon
 1'age  des  poissons;  ces  quantites
 sont  toutefois mortelles  pour  les
 alevins de truite fario en moins de
 10 heures.

   Toxicite du Chlorure de Sodium:
 des tests  a long  terme furent
 poursuivi par P. LAURENT  sur
 de nombreaux a ni m a u xaquatiques
 avec  une solution de  chlorure de
 sodium a 10.000 ppm. Les cyprinides
 resistaient de 10 a 60 jours  selon
 la temperature.  La faune nutritive
 (Asellus, Hydropsyche, Dreissensia,
 Sphaerium)  est plus  sensible: 50%
 disparaissent  entre  2 et 6  jours
 ainsi que les plantes les plus com-
 munes  des  ruisseaux (Gallitriche,
 Melosciadium, Oenanthe).
 GIFTIGKEIT  EINIGER UNKRAUT-
 VERTILGUNGSMITTEL,    INSEK-
 TENVERTILGUNGSMITTEL  UNO
 INDUSTRIEABWASSER. Paul Vivier
 et Maud J. Nisbet. p. 167. Giftig-
 keit von Unkrautvertilgungsmitteln:
 Im Laboratorium und auf dem Ver-
 suchsfeld haben unserebiologischen
 Versuche mit Simazin [(2 - Chlor-4,
 6-bis (athylamino) - 1,3,5 -  Triaziii)
 und  mit Atrazin (2 - Chlor - 4  -
 athylamino  -  6  - isopropylamino  -
 1,3,5 - Triazin) gezeigt, dass diese
 Stoffe   in  wassriger Losung sehr
 giftig,   aber  fur gewisse Pflanzen,
 welche sie unmittelbar absorbieren,
 unsch'adlich sind.   Weedex, Wee-
 dazol,  usw.  sind  im allgemeinen
 weniger  schadlich,  sogar wenn man
 sie in viel hoheren Konzentrationen
 anwendet als  der  normalen Menge
 entsprechen wiirde.

   Giftigkeit von Kupfersulfat: Stu-
 dien von  L.  Mazoit  und  Mitar-
 beitern  uber  lange Versuchszeiten
 hin an einem kleinen Fluss zeigten,
 dass in  6 Tagen 75% der Karpfen
 und Schleien durch 0,2 mg/1 Kupfer
 eingegangen waren. Auch die  mei-
 sten Elritzen waren tot, aber einige
 konnten 0,3 mg/1 ertragen.  In der
 Nahrungsfauna wurden Larven von
 Ephemeroptera  getbtet,  die  von
 Trichoptera   hingegen  nicht;  sie
 schienen  jedoch  erregt  zu sein.
 Das Wasser dieses Flusses war hart.

   Giftigkeit synthetischer  Weich-
 machungsmittel:    Studien  von J.
 Wurtz  -  Arlet zeigten, dass anio-
 nische und nicht ionisierte Weichma-
 chungsmittel fur die Eier und fur
 junge braune Forellen (Salmo fario)
 und  fur  junge Regenbogenforellen
 (Salmo gairdnerii)  giftig  sind.  Die
Werte  fur TLm  fur 24 Stunden sind
 fur Regenbogenforellen 3 bis 5 mg/1,
wobei  das Alter der  Fische eine
 Rolle spielt;  die gleichen Mengen
 sind aber fur  junge braune Forel-
 len bereits  in weniger als 10 Stun-
den todlich.

   Giftigkeit  von  Natriumchlorid:
 P. Laurent  beniitzte in biologischen
 Versuchen mit zahlreichenWasser-
tieren  eine Natriumchloridlosung
von 10 Gramm im Liter. Cyprini-
 den  lebten  darin 10  bis 60 Tage
 lang je nach der Versuchstempera-
tur.   Die Nahrungsfauna (Asellus,
Hydropsyche,  Dreissensia,  Spaer-
 ium) ist  empfindlicher: 50 % gingen
 in 2 bis 6  Tagen  ein.  Die  mei-
sten Pflanzen im Versuchsgewasser
 (Gallitriche,  Melosciadium   und
 Oenanthe) wurden ahnlich betroffen.
                                                        421

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THE VALUE AND USE OF WATER
QUALITY CRITERIA TO PROTECT
AQUATIC LIFE.  A RATIONAL IN-
DUSTRIAL  VIEWPOINT.  Roy  F.
Weston.  p. 9  .No one individual
can  hope  to represent the many
diversified philosophies and opinions
of industrialists  on the subject of
water  quality  criteria.   Factors
common to  most  industrial  op-
erations make it possible, however,
to rationalize  an industrial view-
point.

   Water quality criteria for aquatic
life cannot be considered alone. They
must be considered  as a specific
part of a broad spectrum of criteria
pertaining  to  numerous different
water uses.

   It is  axiomatic that water quality
criteria for the protectionof aquatic
life  are essential  to  an effective
water  pollution  control  program.

   Philosophical concept confuses
the establishment, application, and
enforcement of such criteria.

   The industrialist's policies must
be controlled by his inherent philo-
sophies, his training, his experience,
and  his responsibilities; i.e., (the
hard  facts  of  economic  realism).
Consequently, he must have sound
and  logical  reasons for  expending
funds on water  pollution control.
He cannot rationalize the expenditure
of funds in  excess  of  that which is
essential  to equity or to the pro-
tection of a  stream's best use. Once
this has been established, he has
reason  to expect specific and rea-
sonable water quality  criteria.  He
should  be  required to  meet only
those criteria that  the regulatory
agency  is prepared to  monitor and
to enforce.

   The  establishment and enforce-
ment of reasonable technical and
administrative  policies and  pro-
cedures present one of the greatest
challenges  to the pollution control
profession.   The success or failure
of pollution  control programs de-
pends on the soundness of the regu-
latory agency's actions.
VALEUR ET EMPLOIDES CRIT-
TERES DE QUALITE  DES  EAUX
POUR PROTEGER LA VIE AQUAT-
IQUE  UN POINT DE VUE INDUS-
TRIEL RATIONNEL. Roy F. Weston.
p. 9  .  .    Aucun individu ne peut
esperer representer les philosophies
et opinions  si diverses  des  in-
dustriels  au sujet des criteres de
qualite des  eaux.    Les facteurs
communs  a laplupart des operations
industrielles rendent toutefois pos-
sible la  rationalisation d'un point
de vue industriel.

   Les criteres de qualite pour la
vie aquatique ne peuvent etre con-
sideres  seuls,  mais   comme une
partie specifique d'un ensemble de
criteres  concernant les  nombreux
emplois de 1'eau.

   II  est  evident que  des criteres
de qualite des  eaux pour la pro-
tection de  la  vie aquatique sont
essentiels  pour  etablir  un  pro-
gramme de controle des pollutions.

   Le  concept philosophique confond
1'etablissement,  1'application   et
Pexecution de tels criteres.

   Les lignes  de  conduite d'une
industriel  doivent etre  controlees
par ses philosophies naturelles, son
Education,  son  experience  et ses
responsabilites,  c'est-a-dire   les
dures realites d'une realisme econ-
omique.   En consequence,  il doit
avoir des  raisons solides et logiques
pour  depenser  des  capitaux pour
le controle de  la pollution.  II ne
peut justifier une depense superieure
a  celle necessaire a 1'equite au a
la protection du  meilleur  emploi
d'un cours  d'eau.   Une fois ceci
etablit, il  a raison  d'attendre des
criteres  de qualite, specifiques et
raisonnables. On ne devrait exiger
de lui que les criteres pouvant etre
contr6les  et appliques par le bureau
regulateur.

   L'etablissement  et 1'application
de directives techniques  et admin-
istratives  raisonnables  presentent
un des plus grands defis a  la pro-
fession de controle des pollutions.
Le succes  ou  1'echec  des  pro-
grammes  de controle  depend de la
justesse des actions du bureau regu-
lateur.
WERT  UNO  ANWENDUNG  VON
WASSERGUTENORMEN      Z U M
SCHUTZ DES LEBENS IMWASSER,
EIN RATIONALER    INDUSTRIE-
STANDPUNKT. Roy F. Weston. p. 9,
Niemand kann  hoffen,  der er per-
sonlich die vielen verschiedenarti-
genPhilosophienund Meinungen der
Manner der  Industrie  hinsichtlich
Wassergiitenormen  typisch  dar-
stelle.  Es gibt indessen alien  In-
dustrieen eigene Tatigkeiten, die es
ermoglichen,   einen  industriellen
Standpunkt herauszuarbeiten.

   Wassergiiteeigenschaften konnen
nicht  fur  sich allein besprochen
werden, da sie ein ganz bestimmter
Teil des  weiten Feldes  der  zahl-
reichen verschiedenen Anwendungen
des Wassers sind.

   Es  wird  allgemein  anerkannt,
dass Wassergiitenormen zum Schutz
des Lebens im Wasser fur einwirk-
sames Programm zur Kontrolleder
Wasserverunreinigungen    wichtig
sind.

   Philosophische  Begriffe   ver-
wirren die Festsetzung, Anwendung
und Durchsetzung solcher Normen.

   Die Massnahmen des Mannes der
Industrie  miissen durch  seine an-
geborenen    Philosophien,    seine
Schulung, seine Erfahrung und durch
seine  Verantwortlichkeiten,   also
durch  die harten Tatsachen wirt-
schaftlicher Notwendigkeiten   ge-
zugelt  werden.

   Folglich  muss er  gute und  lo-
gische Griinde fur Geldaufwendungen
fur Wasserverunreinigungskontrolle
haben.  Er kann sich nicht mit sol-
chen   Ausgaben  abfinden,  welche
hoher  sind  als was zur  Sicherung
der  besten  Verwendung des Flus-
ses  recht  und billig ware.  Sowie
diese Verwendung festgelegt 1st, hat
er Grund, ins Einzelne gehende und
wirklichkeitsnahe    Wassergli-
tenormen  zu erwarten.  Er sollte
nur an die Beachtung solcher Nor-
men   gebunden sein,   welche   die
tiberwachungsbehorde     ernstlich
anzuwenden und unparteiisch durch-
zusetzen gewillt 1st.

   Die Festsetzung  und Einhaltung
vernunftiger  technischer  und Ver-
waltungsmassnahmen und Verfahren
stellt  eine  der grossten Heraus-
forderungen  fur die Manner  dar,
welche beruflich mit der Verunrei-
nigungskontrolle zu tun haben.  Der
Erfolg oder Misserfolg der Verun-
reinigungskontrollprogramme  hangt
von  der  absolute^,  Vertrauens-
wurdigkeit  der   ijberwachungs-
behorde und ihren Massnahmen ab.
                                                        422

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 BIOLOGY OF WATER TOXICANTS
 IN SUB LETHAL CONCENTRATIONS.
 Charles G.  Wilber.   p. 326 .   In*
 evaluating the biological effects and
 significance  of water toxicants the
 real importance of time must not be
 underestimated.  All persons work-
 ing with problems of water pollution
 recognize the  significance  of con-
 centration of an  agent.   Time, in-
 cluding  exposure time  and  latent
 period, is a  real factor that modi-
 fies one's estimation of the biologi-
 cal activity of a given toxicant. The
 following general equation is dis-
 cussed and evaluated:
  Ct = K+atb + 1
 where  C is  concentration of toxi-
 cant,  t the  exposure   time,  K  a
 constant  related  to  species  sus-
 ceptibility, a is a constant related
 to magnitude of rate of detoxication,
 and b  a constant  related to change
 in rate of detoxication.  The danger
 of using the  LD50 concept for work
 involving  animals that  carry  an
 aquatic respiration  is  illustrated.
 For  critical biological  assay  of
 water toxicants, the percent survival
 of experimental species at a given
 time gives sparse information.  A
 more  informative program  is one
 involving graded response; in many
 instances such a  program will re-
 quire time periods equal to the total
 length of life of  the test organism.
 In  long-term  exposures the  log-
 arithmic  nature  of biological time
 seems  to be  illustrated; the  at-
 tending problems of this apparent
 phenomenon  are   discussed.   Such
 long exposure  times with  accom-
 panying  low  concentration  of
 toxicant are essential,  if carcino-
 genic materials are under test with
 the view to extrapolation to potential
 human  hazard.   In our laboratory
 we consider essential (and are study-
 ing) the  effect  of long-term ex-
 posures on organ weight-body weight
 ratios;  changes in these ratios are,
 in many  instances, delicate indi-
 cators  of subthreshold effects  of
 toxicants.  Examples from the liter-
 ature  and from  our own data are
presented  to illustrate various
points.    The  question,  "Is  there
any scientifically  acceptable upper
limit  for  carcinogenic  pollutants
in water destined for human use?"
is touched upon.   The obvious re-
quirements for  adequate histopatho-
logical and histochemical studies of
tissues from test specimens is re-
emphasized.
BIOLOGIEDESTOXIQUESDE L'EAU
EN  CONCENTRATIONS  SUB-
LETHALES.   Charles C.  Wilber.
p. 326 .   En evaluent les  effets
biologiques et la  signification des
toxiques  dans 1'eau,  I'importance
reelle du  temps  ne  doit pas etre
sous-estimee. Tous ceux qui
travaillent  sur les problemes de
pollution reconnaissent I'importance
de la concentration d'un produit. La
duree,  comprenant le temps  d'ex-
position et la periode de latence, est
un facteur reel qui modifie 1'esti-
mation de 1'activite biologique d'un
toxique donne. L'equation generale
suivante est  discutee et calculee:

   Ct=K+atb+1
ou C est la concentration du toxique,
t le  temps d'exposition, K une con-
stante liee a  la sensibilite des
especes, a une constante liee a la
vitesse de desintoxication et  b une
constante liee au  changement de la
vitesse de  desintoxication.   Le
danger de  1'emploi   de  la LDso,
concept de travail  pour des animaux
qui  continuent a  respirer,  est de-
montree.   Pour les essais biologi-
ques, le pourcentage de survivants
des  especes  experimentales  a un
moment  donne, donne peu d'infor-
mation.   On  obtient  plus de ren-
seignements  avec des experiences
donnant une response  progressive;
dans bien des cas de  telles ex-
periences necessiteront des durees
egales a  la duree de vie de 1'or-
ganisme test!.  Dans  les essais a
long terme, la nature logarithmique
due  temps biologique semble etre
illustree; les problemes en relation
avec ce phenomene sont discutes.
Les  longues durees pour de faibles
concentrations de  toxiques sont in-
dispensables  s'il   s'agit de  tests
effectues  avec des produits car-
cinoge'nes en  vue de 1'extrapolation
aux  risques humains.  Dans  notre
laboratoire,  nous  considerons
comme essentielle 1'action des
longues exposition sur les rapports
poids des organes  - poids du crops;
des changements dans ces rapports
sont dans bien des cas de precieux
indicateurs  de seuils d'action des
toxiques.

   Des  exemples  choisis  dans la
litterature et  dans nos propres ex-
periences  sont presentes pour il-
lustrer divers  points. Nous abordons
la question   Y a-t-il une limite
acceptable scientifiquementpour les
toxiques  carcinogenes dans  1'eau
destinee a 1'alimentation humane?^'
Nous soulignons a nouveau  la nec-
essite des etudes histopathologiques
et histochimiques  des tissues sur
les specimens d'experience.
 DIE BIOLOGIE VONGIFTSTOFFEN
 IM WASSER  IN  SUBLETHALEN
 MENGEN.  Charles G. Wilbur, p.326
 Filr  die Amswertung  biologischer
 Wirkungen und  die Bedeutung von
 Giftstoffen imWasser darf die Wich-
 tigkeit der  Zeit nicht  unterschatzt
 werden.   Wer mit Problemen der
 Wasserverunreinigung  zu  tun  hat,
 sieht  die Bedeutung der Konzentra-
 tion  eines Stoffes  ein.  Die Zeit,
 einschliesslich  der unmittelbaren
 Einwirkungszeit und der Latenzzeit-
 spanne, andert die Bestimmung der
 biologischen Wirksamkeit einer ge-
 gebenen  Giftsubstanz oft sehr er-
 heblich.   Die folgende allgemeine
 Glei chung:
 C  t  = K + a  tb  +1

 wird  besprochen und ausgewertet.
 In  ihr  1st C die Konzentration des
 Giftstoffes, t  die Einwirkungszeit,
 K ein Festwert im  Zusammenhang
 mit der  Empfindlichkeit der Art,
 a ein Festwert, der mit der Grosse
 der Entgiftungsgeschwindigkeit und
 b ein  Festwert,  der mit der Xn-
 derungder Entgiftungsgeschwindig-
 keit zusammenhangt. Die Gefahren
 in  der Anwendung  des LD^ Be-
 griffes fur Arbeiten mit im Wasser
 atmenden  Tieren  wird  an   Bei-
 spielen gezeigt.  Fur die kritische
 biologische Prufung von jGiftstoffen
 gibt der Hundertsatzdes tJberlebens
 einer  Versuchsart  zu  einer  be-
 stimmten  Zeit nur  spa'rliche Aus-
 kunfte.   Lehrreicher ist ein Pro-
 gramm mit gestuften Ergebnissen;
 ein  solches   erfordert in  vielen
 Fallen  Versuchszeiten,  die gleich
 der Lebensdauer  der   Versuchs-
 organismen  sind.   Dauerversuche
 deuten auf die logarithmische Natur
 der biologischen Zeit hin;  die die-
 sen mbglichen Zusammenhang be-
 gleitenden Fragen werden erortert.
 Lange Versuchszeiten und die damit
 verbundenen niedrigen  Konzentra-
 tionen der Giftstoffe sind besonders
 wichtig, wenn krebserregende Stoffe
 in der  Absicht gepr'uft werden, aus
 den Ergebnissen  Schlusse  auf die
 moglichen Gefahren fur  den Men-
 schen  zu ziehen.   In  den Dauer-
 versuchen, welche in unserem La-
 boratorium im  Gange sind, halten
 wir die Feststellung der Verh'alt-
 nisse  Organgewicht/Korpergewicht
 fur notwendig; Anderungen indiesen
 Verh'altnissen sind in vielen Fallen
 empfindliche Nachweise  von Gift-
wirkungen, die  gerade  noch  unter
dem Schwellenwert der betreffenden
 Gifte liegen.  Zur Erlauterung der
angeschnittenen  Fragen   werden
Beispiele aus der Literatur und aus
eigenen Versuchsreihen mitgeteilt.
Die  Frage ,,Besteht  eine  wissen-
schaftlich annehmbare obere Grenze
fur  krebserregende Verunreinigun-
                                                        423

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                                                                                geninWasser,das fur menschlichen
                                                                                Genuss  und  Gebrauch  vorgesehen
                                                                                1st?" wird  aufgeworfen.  Die klare
                                                                                Notwendigkeit   fur   hinreichende
                                                                                histopathologische   und histoche-
                                                                                mische  Studien an  Gewebeprobe-
                                                                                stucken wird wiederum betont.
SOME RESULTS OF  OYSTER -
PULP MILL  WASTE  BIOASSAYS.
Charles E.  Woelke.  p. 67  .  Five
general types of bioassays  of sul-
phite  waste liquor with oysters,
carried out by the Washington State
Department of  Fisheries, are de-
scribed.   These include  field live
boxes in waters receiving sulphite
waste liquor, long range  laboratory
bioassays, and finally, 48-hour bi-
oassays  of  field water  brought to
the laboratory.   Based on the re-
sponse of adult Olympia oysters
(Ostrea lurida)  in field  live boxes
and  in long  range bioassays,  of
adult  Pacific oysters  (Crassostrea
gigas) in  lagoon studies, and of the
larvae of both  species  in short-
term  laboratory and field water bi-
oassays,  it is  concluded that the
fertilization and embryonic develop-
ment  processes of both species are
affected at lower concentrations of
sulphite waste liquor  than the con-
centrations  that  affect the adults.
To  determine whether the toxicity
of sulphite waste liquor  present in
the receiving waters differs from
that  of dilutions prepared  in the
laboratory,  larval responses at the
same  levels are compared.
DBS RESULTATS SUR LES HUITRES
 Charles^E; Woelke.  p. 67  .  Cinq
 types  generaux de tests de pertes
 deA liqueurs  sulphites relative aux
 huitres qui ont ete mis a execution
 par  le department des p^cheries
 d'etat  de  Washington, sont decrits.
 Ceux-ci incluent les pares dans les
 eaux recevant  ces pertes de liqueur
 sulfite, une grande etendue de test
 en laboratoire et finalement 48
 heures de tests d'eau de  terrain
 apporteeau laboratoire.   Base sur
 le test de reaction de 1'huitre adulte
 Olympia  (Ostrea   lurida)  en pare
 et de  longue duree  et de  1'huitre
 adulte Pacific  (Crassostrea gigas)
 etudie en lagune,  et des larves des
 deux especes etudies  en laboratoire
 et en eau de terrain, il est conclu
 que  la fertalisation  et le precede
 de   developpement   embryonnaire
 sont affectes au plus basses con-
 centrations de liqueur  sulphite
 perdues que les concentrations qui
 affectent  les  adultes.   La  deter-
 minaison de la toxiquitede la liqueur
 sulphite perdue dans les eaux differ e
 des  dilutions preparees  en labora-
 toire.   Les reactions des  larves
 au memetaux sont comparees.
EINIGE    BIOVERSUCHSERGEB-
NISSE  MIT AUSTERN IN  ZELL-
STOFFABRIKABWXSSERN.  Charl-
es E. Woelke.  p. 67  . Es werden
flinf  Bioanalysenmethoden zur  Un-
tersuchung  von   Zellstoffabrikab-
wassern  mit Austern, wie  sie am
Washington   State  Department  of
Fisheries  durchgefuhrt   wurden,
beschrieben,  darunter die Anwend-
ung vonKa'steninGew'assern,welche
die Zellstoffabrikabwasser fuhrten,
Laboratoriumsdauerversuche   mit
lebendem Material und schliesslich
48-Stunden-Bioversuche  an Fluss-
w'assern  im  Laboratorium.   Aus
dem Verhalten  erwachsener Olym-
piaaustern (Ostrea lurida) in   Ka-
stenan Ort und  Stelle und in Dauer-
versuchen,  mit  Pazifischen  Aus-
tern   (Crassostrea gigas)  in  La-
gunenstudien und  mit den  Larven
beider   Arten   in   kurzfristigen
Laboratoriumsversuchen  und  Bio-
versuchen  an  Ort und Stelle wird
geschlossen,  dass die Befruchtung
und  die    Embryonalentwicklungs-
prozesse  beider  Arten    durch
geringere   Konzentrationen   von
Zellstoffabrikabwassern    beein-
flusst werden als erwachsene Tiere.
Zwecks Feststellung, ob die Giftig-
keit  der Zellstoffabrikabwasser in
den Vorflutern  von jener verdunnter
Laboratoriumslb'sungen  verschie-
denist, wurden die Reaktionen von
Larven unter  identischen Konzen-
trationsverhaltnissen verglichen.
                                      230 Eo-^-.li
                                                        424
                                                                                                     GPO 816-361-16

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