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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Page
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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Page
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
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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
-------
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-
-------
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.
-------
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
-------
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.
-------
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-
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Foged, N. 1951 (1955). The diatom flora of some
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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.
-------
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.
-------
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
-------
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.
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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
-------
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.
-------
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.
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ENVIRONMENTAL REQUIREMENTS OF PLANKTON ALGAE
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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.
-------
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,
-------
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//
I ° ! I:1'
//*'$''/
• :' 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.
-------
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.
-------
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
-------
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
-------
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
-------
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.
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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.
-------
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
50
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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
100
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70
60
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40
30
2.5 ppt
5.0 ppt 15.0 ppt
25.0 ppt
20 25 30 J20 25 30 20 25 30 |20 25 30
33.0 ppt
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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SIV
Sill
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SI
20 25 30 20 25 30
20 25 30
20 25 30
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.
-------
82
ENVIRONMENTAL REQUIREMENTS OF MARINE INVERTEBRATES
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TEMPERATURE, °C
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
u
Ul
a.
ui
35
34
33
32
31
30
29.
28
27
26
25
24
23
22
21
20
19
18
17
16
15
100
10
15
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
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 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
UJ
C£
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ee.
m
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35
34
33
32
31
30
29
28
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22
21
20
19
18
17
16
15
I ' • ' ' I
10
15
20
25
30
35
40
SALINITY, ppt
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.
a.
UJ
35
34
33
32
31
30
29
28
27
26
25
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23
22
21
20
19
18
17
16
15
' 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.
-------
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.
-------
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
-------
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
-------
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).
-------
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.
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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.
-------
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.
-------
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.
-------
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
-------
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.
-------
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.
-------
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.
-------
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).
-------
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.
-------
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.
-------
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.
-------
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.
-------
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
-------
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
-------
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
-------
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).
-------
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
-------
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
-------
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)
-------
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
-------
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
-------
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)
-------
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
-------
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?
-------
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.
-------
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.
-------
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
-------
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
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DISSOLVED OXYGEN CONCENTRATION, mg/l
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1956 TESTS
A 1956 TESTS
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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.)
-------
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
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EXPERIMENT-1-(15 DAYS)
EXPERIMENT-2-(15 DAYS)
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DISSOLVED OXYGEN CONCENTRATION, mg/1
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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
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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
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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
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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
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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-
-------
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
-------
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.
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1957. The survival of rainbow trout (Salmo guird-
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Alderdice, D.F., W. A. Wickett, and J. R. Brett.
1958. Some effects of temporary exposure to low
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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-
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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-
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Davison, R. C., W. P. Breese, C. E. Warren, and
P. Doudoroff. 1959. Experiments on the dissolved
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Doudoroff, P. 1957. Water quality requirements
of fishes and effects of toxic substances. In: The
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1960. How should we determine
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of low oxygen and other extreme conditions on
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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
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Fish. Soc., 89: 17-26.
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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.
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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.
-------
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
-------
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.
-------
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.
-------
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,
-------
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.
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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
-------
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
-------
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
-------
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.
-------
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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1^ — - -* -^ j — — —
tciin Ginbrvonic st3.£[6s Th© ctppliccttion of these two
methods was necessary in order to be able to dis-
15
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8-10 12-14 16-18
WEEKS AFTER HATCHING
Q
K %^-.
^S^\> ''••.
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•^>^^ /
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1/2 FRESH \ • .'
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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.
-------
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.
-------
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.
-------
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.)
-------
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
-------
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.
-------
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
-------
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.
-------
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).
-------
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
-------
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.
-------
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.
-------
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
-------
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.
-------
230
BIOLOGICAL INDICATORS OF POLLUTION
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Butcher, R.W. 1947. Studies in the ecology of
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Butcher, R.W. 1955. Relation between the biology
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Fjerdingstad, E. 1960. Forurening af vandl^b bio-
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Hustedt, F. 1957. Die Diatomeenflora des Fluss-
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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.
-------
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.
-------
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
-------
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.
-------
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
-------
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.
-------
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
-------
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
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Hynes, H.B.N., and Roberts, F.W. 1962. The bio-
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logischen Fliesswassertypisierung. Arch. Hydro-
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Jones, J.R.E. 1940a. The fauna of the River Mel-
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Jones, J.R.E. 1940b. A study of the zinc-polluted
river Ystwyth in north Cardiganshire, Wales. Ann.
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Kolkwitz, R. 1950. Oekologie der Saprobien. Uber
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Lackey, J.B. 1957. Protozoa as indicators of the
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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-
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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.
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carp in running water in West Java Proc. Indo-
Pacific Fish Council 6: 187-96. F.A.O. Bangkok.
-------
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.
-------
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.
-------
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.
-------
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.
-------
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.
-------
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.
-------
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.
-------
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.
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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.
-------
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.
-------
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
-------
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.
-------
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.
-------
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.
-------
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.
-------
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.
-------
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
lu.
0.
- 1.0
UJ
f^ 0 8
U 0-4
0.2
0
r
^
r^1
S
^
^>
H- -
"^— ^
.
.^-
^ -^
HOURS IN WATER
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
600
500
400
2OC
to
3
E. S0
UJ 40
20
15
10
6
5
4
0
-
03
.
T
\
\
V
Vi
\\
V \
1 \
\ V
\ \
\\
V
\
O.I
\(o)
v\
\\
\\
V \
V
\
A
i \
^
3 .
s
Vv
4 .
N
^
b.
x
x
\
BROWN TROU
SM ALLMOUT
\
"V
.
1
,
i.o as'
-
-
H-
} t
-
\~
-
r~ t
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
-------
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?
-------
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
-------
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.
-------
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.
-------
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.
-------
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
-------
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.
-------
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.
-------
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.
-------
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.
-------
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
-------
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.
-------
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.
-------
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.
-------
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.
-------
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.
-------
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.
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Effects of Cooling Water from Steam-Electric Power Plants on Stream Biota
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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.)
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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
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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.
-------
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.
-------
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.
-------
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
-------
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,
-------
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.
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362
DETERMINATION OF SAFE LEVELS OF TOXICANTS
Christenson, C.W., E.B. Fowler, B.L. Johnson, E.H.
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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
-------
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.
-------
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.
-------
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.
-------
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
-------
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.
-------
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
-------
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
-------
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
-------
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
-------
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
-------
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
-------
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
-------
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
-------
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
-------
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
-------
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
-------
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
-------
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
-------
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
-------
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.
-------
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
-------
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
-------
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
-------
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
-------
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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