EPA-600/9-75-004 *
             MARCH 25-29. 1974


  These  proceedings include  the  24 papers presented  at  the  first  U.S./USSR
Symposium on  Comprehensive Analysis of the Environment. The  papers  were
originally presented in English and Russian at Tbilisi, Georgia, USSR,  between
March 25 and March 29,  1974. Their publication herein is  part of the  protocol
agreement signed on March 29,  1974, for simultaneous and independent  publica-
tion in both countries after coordination of the  manuscripts.
  The success of the first symposium on Comprehensive Analysis of the Environ-
ment resulted from the efforts of many persons who planned the agenda, arranged
facilities, coordinated papers and their translation,  and attended to the myriad of
details which occurred through the symposium. The productivity of the 1974 sym-
posium and its fruitful exchange of ideas were a vivid  realization of the objectives
in the Agreement on Cooperation in the Field of Environmental Protection, signed
in Moscow on May 23, 1972.
  Achievement of  these plans is a special credit to the  Soviet delegation under
their leader, Professor Yu. A. Izrael, First Deputy  Chief of the  Main Administra-
tion of the Hydrometeorological Service, Council of Ministers of the USSR. Since
the Tbilisi symposium, now Academician Izrael has succeeded Academician E. K.
Fedorov as Chairman of the Soviet Side of the Joint  Committee on Cooperation
in the  Field of Environmental Protection. The warm appreciation for all his help
has been  duly noted by the  head of  the American delegation, Dr. Stanley M.
Greenfield, Assistant Administrator for Research  and Development, U.S. Environ-
mental Protection  Agency. The  American contributions were  compiled  by Dr.
Leland D. Attaway, Deputy Assistant  Administrator for Program Integration, U.S.
Environmental  Protection  Agency. Completion  of these proceedings has been
directed by Roger S. Cortesi, Director of the Washington Environmental Research
Center, U.S. Environmental Protection Agency,  who  succeeded Dr. Attaway as
Chairman of this U.S. Working Group Project.


      Comprehensive  Environmental  Management, an  Overview—
        S.  M. Greenfield 	    1

      Systems Analysis  and Simulated Mathematical Modelling as a
        Methodological Basis for the Standardization of Anthropo-
        genic Approach—Yu. A. Izrael, Yu. A. Anokhin 	    5
      A Comprehensive Environmental Analysis of the Upper Potomac
        Estuary  Eutrophication  Control   Requirements—N.   A.
        Jaworski 	    15
      The Ecological System Stability Concept—V.D. Fedorov 	    27
      Development of Maximum Permissible Environmental  Loading-
        Air—B. J. Steigerwald 	    35

      Estimating the Maximum Permissible  Intensity of the  Complex
        Effect of Chemical Factors in the Production, Municipal, and
        Domestic Environment on Man—N. F. Izmerov	    45
      The Concept of the Threshold Nature of Reaction of Living Sys-
        tems to External Actions and its Consequences in the Problem
        of Protecting the Biosphere against Chemicals—I. V. Sanot-
        skiy  	    49
      Questions of Extrapolating Data in Evaluating the Mutagenic
        Action of Environmental Factors on Man—N. P. Bochkov ....    55
      The Question  of  Genetic Danger from  Environmental Pollu-
        tants—L.  M. Filippova  	    59
      Hygienic Bases for Protecting  the Environment—G. I. Sido-
        renko, Ye. I. Korenevskaya, G. N. Krasovskiy  	    63
      Hygienic Normalization under Scientific and Technical Progress
        Conditions—A. P.  Shitskova, M. I. Gusev, S. M. Pavlenko,
        I.  L. Karagodina 	    67
      Maximum Permissible Human Stress—V. Newill  	    71
      Maximum Permissible Human Stress with Multiple Pathways:
        lonization Radiation, Asbestos and Lead—J. H. Knelson	    81
      Complex Analysis of the Environment—Approaches to a Deter-
        mination of the Permissible Loads on the  Natural  Environ-
        ment and to a Justification for Monitoring—Yu. A.  Izrael ....    89
      Defining "No Significant  Deterioration" of Air Quality—R. A.
        Luken 	    95

      Determining Acceptable  Levels of Health and Environmental
        Damages—F. H. Abel 	   107

       Methods for Abatement of Water Pollution—R. B. Schaffer ....  117
       Methods for Control of Air Pollution—K.  E. Yeager 	  125
       Development of Maximum Permissible Environmental Loading
         (MPEL)-Water—M. A.  Pisano 	  139

       The Effect of Polluting a Biogeocoenosis with Strontium 90 on
         a Population of Mammals and  the Zoocoenosis—V.  Ye.
         Sokolov, A. I. Ilycnko, D. A.  Krivolutskiy	  149
       Effects of  Pollution  on Species  and Populations  of  Fish  and
         Birds—H. E. Johnson 	  159
       The Influence of Environmental Factors on Population Dynamics
         (Mathematical Models)—M. Ya. Antonovskiy  	  171

       Global Climate and Human Activity—M. I. Budyko, I. L. Karol  179

       Concluding Remarks for the U.S./USSR Symposium on Compre-
         hensive Analysis of the Environment—L. D. Attaway 	  187

Dr. Stanley M. Greenfield

Dr. Leland D. Attaway

Dr. Frederick H. Abel

Dr. Norbert A. Jaworski

Dr. Howard E. Johnson

Dr. John H. Knelson
Dr. Ralph A. Luken

Dr. Mark A. Pisano
Mr. Robert B. Schaffer

Dr. Louis J. Schoen

Dr. Bernard J. Steigerwald
Mr. Kurt E. Yeager

Prof. Yu. A. Izrael

Dr. Yu. A. Anokhin
Prof. M. Ya. Antonovsky
Head of Delegation
Assistant Administrator for Research and Devel-
  opment, USEPA
Co-chairman,  Comprehensive Analysis of the En-
  vironment Project
Deputy Assistant Administrator for Program Inte-
  gration, USEPA
Chief, Economic Analysis Branch, Washington En-
  vironmental Research Center, USEPA
Director, Pacific Northwest Environmental Research
  Laboratory, USEPA
Private Citizen, Associate Professor, Department of
  Fisheries and Wildlife Michigan  State University
Acting Director, Human Studies Laboratory, USEPA
Private Citizen, Consultant  on Environmental Eco-
Special Assistant to the Administrator, USEPA
Director, Water Planning Division, USEPA
Acting Director, Permit Assistance and Evaluation
  Division, USEPA
Special  Assistant  for International Research and
  Development, USEPA
Director, Office of Air Quality, USEPA
Chemical  Engineer, Office of Research and Devel-
  opment, USEPA
Co-chairman, Comprehensive Analysis  of the En-
   vironment Project
First Deputy Chief of Main Administration of Hydro-
   meteorological Service, Moscow
Institute of Applied Geophysics, Moscow
Central Institute of Economic Mathematics, Moscow

Prof. M. E. Berljand
Prof. M. I. Budyko
Prof. V. D. Fedorov
Dr. L. M. Filippova
Prof. M. I. Gusev
Prof. G. F. Hilmi
Prof. A. I. Ilyenko

Dr. N. F. Izmerov

Dr. V. S. Jurkov
Prof. I. L. Karol
Dr. Yu. E. Kazakov

Dr. G. N. Krasovsky

Dr. B. A. Kuvshinnikov

Prof. M. J. Lemeshev
Dr. V. P. Lominadze

Prof. A. M. Molchanov
Dr. I. M. Nazarov
Dr. V. G. Novozhilov

Prof. I. V. Sanotsky

Acad. S. S. Shvarts
Main Geophysical Observatory, Leningrad
Main Geophysical Observatory, Leningrad
Moscow State University, Moscow
Institute of Applied Geophysics, Moscow
Institute of Hygiene, Moscow
Institute of Applied Geophysics, Moscow
Institute of Evolutional Morphology and Ecology of
  Animals, Moscow
Institute of Labour Hygiene and  Professional Dis-
  eases, Moscow
Institute of Medical Genetics, Moscow
Main Geophysical Observatory, Leningrad
Joint Soviet-American  Committee, the Soviet Part
  of the Project
Institute of General and Communal Hygiene, Mos-
Joint  Soviet-American  Committee, the Soviet Part
  of the Project
Central Institute of Economic Mathematics, Moscow
Director of Transcaucasian Hydrometeorological  In-
  stitute, Tbilisi
Computer Centre, Puschino-na-Oke
Institute of Applied Geophysics, Moscow
Assistant Chief of Main  Administration of Hydro-
  meteorological Service, Moscow
Institute of Labour Hygiene  and  Professional Dis-
  eases, Moscow
Institute of General Biogeocenology and  Ecology,

  The Joint Committee on Cooperation in the Field of Environmental Protection
was established by the signing of an agreement in Moscow,  May  23,  1972.  This
was followed by the Second  Session of the U.S./USSR Joint Committee in the
Field of Environmental Protection (Washington, D.C., November 16, 1973).
  From these organizational meetings, eleven areas were specified for cooperative
investigation and exchanges. Within these broad areas a number of projects  have
been identified. These proceedings  are  based on one of  these projects: Project
VII-2.1, Comprehensive Analysis of the Environment, within Area VII—Bio-
logical and Genetic Ecects of Environmental Pollution.  In accordance with pro-
visions of the  Memorandum of the Second  Session, the symposium at Tbilisi was
scheduled to bring together experts  from both countries for  presentation  and dis-
cussions of papers in this area. This area is unique in the comprehensive  perspec-
tive of its approach to environmental problems; consequently the contents or titles
of some of the papers could suggest that they are  more germane to other  program
  The proceedings are arranged to  present papers in topical clusters,  and do not
necessarily reflect the original sequence of  presentations. Papers from each  dele-
gation are intermingled to emphasize the contrast in  approaches,  and suggest the
lively discussions which they engendered.
  Primary emphasis was  given to  the determination of scientifically permissible
loading on the environment. This emphasis  considered the  comprehensive analysis
of the pollution sources and  receptors  as well as approaches to the development
of criteria for scientifically permissible stress to the environmental and identification
of critical links in this development.
   The Tbilisi symposium  identified the following problems which will require at-
   (1) More complete accounting of pollution sources and receptors, types of im-
pacts and biological reactions, as well as peculiarities of the area  or region where
such impact occurs;
   (2) Investigation of  dose/response  relationships in lexicological, genetic, and
other experiments;
   (3) Scientific substantiation of environmental  monitoring techniques with due
consideration of critical links in analyzed systems;
   (4) Studies of  the fate and effects  of multimedia pollutants, supplemented by
development of the required standards;
   (5) Assessment of the needs for separate standards limiting long- and short-
term dosages of selected environmental pollutants;
   (6)  Methods for evaluaing the response of ecosysems to varying environmental
   (7) Development of  criteria for  scientifically permissible environmental loading
and identification of critical links;
   (8) Development of practical quantitative methods which will permit compre-
hensive environmental analysis to be applied effectively to environmental problems;
   (9) Development of methodology for assessment of possible economic damage
resulting from man's impact on the environment; and
   (10) Feasibility of a joint U.S.-USSR monitoring system.
   The next meeting on the Comprehensive Analysis  of the Environment, or Sym-
posium II, is scheduled  for the Fall of  1975,  and  will have as its theme:
   Maximum  Acceptable  Environmental Stress on Organisms, Populations, Eco-
systems and the Biosphere as a Whole.

  Comprehensive  Environmental  Management—An Overview
                                     Stanley M. Greenfield *
  From a regulatory sense, it is possible to sepa-
rately consider individual pollutants emerging from
single sources  into a single  medium. Experience has
shown, however, that to derive a strategy that will
ultimately result in environmental quality, one must
comprehensively consider the entire complex inter-
acting  environmental system within the  context of
operative socio-economic constraints. Such consider-
ation must take into account the distribution of pol-
lutant sources  throughout the spatial region in ques-
tion, and  their intensity variation with  time. What
then must be derived is a  mechanism  for specifying
the required temporal and spatial variation in effluent
so as to produce the desired environmental  quality.
Implicit in such a determination is the  recognition
that ultimately there must be a balance  in the cost
of achieving this level of quality and the benefit that
accrues to society in its achievement.  All of human
activity, in one way  or another stresses the environ-
ment. The question is, how much stress is acceptable,
and how is  such a limit achieved and  maintained?
Obviously, within limits, a  society could choose the
degree of environmental management  it desires, the
limits on the choice  of degree being when it permits
those levels of stress to occur which produce  irre-
versible, deleterious impacts on the society itself. The
basic question at  issue, however, is  how does the
society properly make  such a choice? And, within
the context of that question, what information is re-
quired to  make such a decision? What trade-offs are
to be considered? What are the potential methods of
implementation of any  given management strategy?
What analytical tools are available and/or required?
What is the proper  relationship between short-term
goals to accomplish an immediate end,  and long-
term goals to  find a  lasting solution?
   First on any list of information required for such
a decision process must be some determination of the
maximum permissible species stress. This concern is
conveniently divided into  two basic areas,  first the
effects associated  with  human health,  and second,
those associated with the other segments of  the eco-
logical system.
   In the case of health effects, we immediately face
the  dilemma of social risk  and  its  acceptable level.
Are we to consider the economic questions associated
with protecting populations, and are these to enter
into  any  determination  of maximum  permissible
stress? The  first inclination is to dismiss  economic
and  social risk as an  inappropriate consideration
within any discussion of human health. This is par-
ticularly easy to do when one is faced with a health
effect threshold clearly defined and applicable to the
population as  a whole.  In general,  however, this
simple case is seldom realized. What we are normally
faced with is either a dose-response curve with con-
siderable uncertainty near zero dose, or a threshold
that varies with different subgroups of the population
(e.g., cardiovascular sufferers,  etc.). The dilemma is
clear in both cases. It is possible or desirable to pro-
vide a level of  maximum permissible risk that is not
protective of the entire population? Conversely, is it
desirable or necessary to protect  down to the last
noticeable effect, when to do so may require literally
the forbidding  of the flow of any quantity of a par-
ticular pollutant into the environment over and above
the natural background?
   In addition  to  the  relatively simple  case  of the
single pollutant as a unique stressor in a unique path-
way, we must consider the implication of the  syner-
gistic and nonsynergistic effects of  multiple stressors,
and the equally complex multiple pathway single pol-
lutant case. In the rst case, one is possibly implying
a lowest common denominator maximum permissible
stress that depends on what other pollutants are pres-
ent  in the environment.  In the latter case, such as
lead and its many pathways to man, we are faced with
a maximum  permissible  stress depending on the
mechanism of  uptake and some consideration of the
relative intensity of various intake models available.
   The  data  that  underlie  the  determination  of the
maximum permissible stress for a given pollutant are
not particularly impressive. They  become  even less
impressive  when   one  considers  multiple pathway
 and/or  multiple  pollutants. Epidemiologic  experi-
 ments are difficult to carry out and when stratified to
reveal the single or specific multiple pollutant effect,
 quickly reduce even a large body of data to an in-
 sufficient sample.  Animal lexicological experiments
 are difficult to carry out successfully for the long
  •AMittaat Administrator for Research and Development, U.S. Environmental Protection Agency

periods of time required, and suffer in their transla-
tion to man. Yet, the ability to state the maximum
permissible stress is the  cornerstone to being able to
describe an adequate control  plan, and to provide
the  input  options  for  an adequate  environmental
management system. In  addition, adequate ability to
quantify the stressor-effect relationship is mandatory
if we  are  to  ultimately describe  the  social conse-
quences of various  levels of pollutant concentrations.
   Of particular interest  here is the question of non-
degradation, or the decision to not permit a region
that is  currently below the maximum  permissible
stress to degrade so as to reach that limit. This is an
extremely  difficult  question  to  deal with from both
a philosophical and social standpoint.  It starts with
the assumption that we have established a maximum
permissible stress.  Philosophically or pragmatically,
do we now allow all areas to be polluted up to that
point or are we determined to hold the environmental
quality of  relatively  unimpacted areas? The former
implies that the  maximum permissible stress  repre-
sents a level to which we will allow all levels to rise.
The cost of nondegradation must be very carefully
weighed against the social benefits that accrue.
   All of the issues raised in describing  the process
of obtaining a maximum permissible environmental
stress for health  effects  are applicable to the case of
ecological  effects as  well:  threshhold  versus non-
threshold pollutants, benefits of given levels of maxi-
mum permissible stress,  defense of especially sensi-
tive  subpopulations, simple  pollutants,   multiple
stresses, both  synergistic and  nonsynergistic,  and
multiple pathways. In  general, however,  the  eco-
logical  effects  require an even  greater consideration
of the social benefits that accrue to a given level of
permitted  stress  or control. Obviously, we are deal-
ing with a larger set of intangibles as opposed to the
relatively more easily defined area of health protec-
tion.  The  result  is  that  a society which  can under-
stand and  accept costs attached to protecting human
health has  a great deal of trouble justifying large costs
to protect  ecological systems. The interrelated char-
acter of our  environmental system  is little under-
stood outside of the scientific disciplines.  The idea
that damaged  species in an ecological system can
produce irreversible  effects  in  the entire system is
difficult  to grasp and hence, demands an  overt  at-
tempt to trace  the  relationship  through to  a clearly
denned societal cost and benefit. The one area where
this is possibly not true  in the consideration of eco-
logical effects  is  that involving  impacts on the food
chain that  can  more easily be visualized by the lay-
man as having a definable effect on man. These ef-
fects, of course, are even more  difficult to deal with
from a technical  sense and involve an in-depth con-
sideration of the complex multiple pathways, multiple
stressor interactions. However, the ability to demon-
strate that  man is destroying  his food web has a pro-
found effect that leads to a recognition in society of
the benefits that accrue and a willingness to accept
the high "cost" of prevention.
   To this point, we have  been discussing the  pol-
lutants, the pathways, and the maximum stress allow-
able through these pathways so as to protect various
species.  The information obtained  must provide a
sense of the levels of control necessary in these path-
ways to provide the required protection, and a sense
of the population at risk as a function of the applied
controls. In essence, this represents the first step in a
decision making process leading to effective manage-
ment of the environment. The decision maker, how-
ever, must have the ability to address  the  control
options available to him and the cost, both social and
monetary, that apply to the various levels.
   There  are two basic control  options  available—
technological,  and  process  or operations manage-
ment. In the technological  case, we are referring to
specific waste stream controls that can be applied to
specific sources. Typically, these are stack gas clean-
ers, biological treatment  plants, etc., hardware  solu-
tions for clearly  defined waste streams. The process
or operational option refers to changes in the way the
pollutant is produced so as to limit the effluent. In
the  case of a specific plant, this  could involve a
change in an internal chemical process (e.g., substitu-
tion for  the mercury cell in a chlor-alkali plant). In
the case of a widespread source, such as transporta-
tion, it could involve a management process that re-
sults in a change in use pattern. Sources considered
can be either stationary or mobile, located at a point
as in the case of a power plant or widespread  as hi
the case of agriculture. Pollutants can be those that
are emitted in final deleterious form  (e.g., radioactive
gases, carbon  monoxide, etc.)  or  take form  after
emission (e.g., photochemical smog, sulfates, etc.).
   The acceptability of a given control option is de-
pendent  on both its dollar and social cost. A typical
example of a dollar and  social cost is the combined
cost of  restricting  the  use of automobiles  and the
social  acceptability  or  unacceptability of such con-
straints.  These must 'depend on  the  level of stress
limitation desired. Yet, this is not an explicit factor
in the sense that to some  undetermined degree the
maximum permitted stress  is dependent on the  cost
that society must pay.  The decision maker in man-
aging the  environment requires, therefore, a deter-
mination of the economic costs of various options as
a function of desired control level  as  well as some
estimate of the variation  in the institutional impacts
that result. This  then provides him with the ability
to take the second step in the decision making proc-
ess, the information  that will permit option trade-offs
to be examined.
  The final step in this process of developing an en-
vironmental management plan involves the develop-
ment of an  operational  strategy within which  the
various trade-offs can be examined. In essence, these
sets of strategies represent control plans involving the

effluent quality and its variation with  time for all
sources distributed  over  the  entire  region.   The
strategy, therefore, represents a plan for limiting the
stress to the maximum permissible  by limiting the
maximum permissible  loading,  and distributing this
over the region by  assigned source effluent limits.
Obviously,  adequate  knowledge of  control  costs,
stress impact, and  source distribution  in  time and
space will permit the construction  of  management
strategies  that can  be optimized either singly  or  in
combination around  various conditions (i.e.,  cost,
maximum protection, etc.). The independent variable
in all cases is the date by  which  a given level of pro-
tection will  be achieved.
   Strategies for managing the environment can be
subdivided into two basic classes, the first being the
case described previously of preventing an area that
is currently clean from ever reaching the maximum
allowed stress and the second being the implementa-
tion of strategies that force a currently polluted area
to recover a quality environment at least  equal  to
the maximum permissible stress.
   In the  first case, the point at issue  concerns the
price that society is willing to pay to keep a  clean
area clean.  Within this issue is the requirement  to
define what we mean by clean. We presumably have
already established a  level of maximum permissible
stress. Further, we have already indicated that level
in all probability is not an absolute protection for  all
affected species. Does this imply that nondegradation
means zero increase above present levels? Or con-
versely, does it imply  an  allowable increase that will
not  permit  the stress  to exceed a stated  fraction of
that which  is the  maximum permissible?  The first
case will demand a cost which will probably make it
impossible for any additional development to occur.
The second might permit some  limited development,
but  at a  stated cost that may  or  may  not be  unac-
ceptably too high.  It is clear that with the approval
of society,  the description of the acceptable nonde-
gradation level can be used as a mechanism for pro-
tecting designated  areas from development   of  a
certain character, and restrict development to  speci-
fied areas. It becomes, in effect a deliberate tool for
land use management.
   It is certainly attractive to  consider the ultimate
protection of pristine areas  and the demand for an
absolute  nondegradation. It must  be pointed out
however, that too restrictive a demand can be coun-
terproductive to  the environmental needs  of society.
Imagine,  for example, a nondegradation level that is
 so restrictive as to permit development to occur only
 in the already polluted and degraded areas. It is clear
that such an approach would  condemn  the  highly
 developed,  most populated areas to ever increasing
 development and stress.  Once again,  it is  necessary
 to carefully balance the costs and benefits  to society
 of the management actions to be taken in the sense
that any management tool is a two-edged sword that
badly used  can be  more  damaging than inaction.
Used intelligently,  the nondegradation issue can help
control  and alleviate the environmental stress in the
more polluted areas,  can protect the pristine areas,
and can provide for an orderly growth in the desig-
nated regions.
   In  the second case, the case of environmental re-
covery, we are attempting to work with an area that
is normally heavily populated, heavily developed, and
most probably of  strong economic importance. The
problem the environmental manager faces is how to
design a program of distributed control for the region
that takes into account  the temporal and spatial dis-
tribution of sources and further, that this program of
control provides the region  with an  environmental
quality  that is within the maximum permissible stress
without destroying its  socio-economic viability.  In
addition, a  decision must be made as  to the desired
date of achievement of this level of control. The con-
trol plan evolved and the attainment schedule chosen
are obviously related when considered in the context
of cost-benefit balancing. This is true both in the sense
of  the  stipulated maximum permitted stress  as indi-
cated previously,  and in the distribution of  control
level and its designated time  of application. The abil-
ity to do so, however,  implies a capability to assess
the social risks of a given stress level and its period
of  maintenance,  and to accurately assign  a stress
level contribution  to each source. Under the influence
of  total cost as related to benefits, one  might stipulate
a decreasing maximum permissible stress with  in-
creasing time, paced to match into the achievement
ultimately of a more effective control  capability with
a smaller societal cost. Obviously, this must  also be
paced with the cumulative social disbenefits that may
increase with the delay  in the achievement of the ulti-
mate  maximum  permissible stress.  What  we  are
searching for then is the ability to minimize the sum
of direct abatement costs  (whether actual economic
costs for control  equipment or social costs  due to
 operational  changes, such  as  reduced  automobile
 use), and the social costs of delaying the  achieve-
 ment of the most desirable maximum  permissible
    One important note of caution must be sounded in
 the above approach. Unless considered directly, and
 included in the management plan, one may find that
 this approach contains no incentive for ever acquir-
 ing the techniques for achieving the most  desired
 maximum permissible  stress. The approach utilized
 to date, particularly in the  United States, has been
 directed primarily towards setting maximum  permis-
 sible stress on the more restrictive grounds of  en-
 vironmental effects as determined,  and the achieve-
 ment date as a legislated mandate.  What cost-benefit
 analysis is done, is  normally done after the fact of
 setting the values of these parameters. In defense of

this system: First, it does not require knowledge, as
described above, that is  not currently available to
the extent needed; hence, it does not delay the regula-
tory process. Second, it does force the development of
techniques to achieve  the desired levels.  The unde-
sirable  feature  of  this  system is that it  may be
counterproductive in  its attempt  to  protect society
and at the very least, it is  an abrasive system that
puts a premium and a relatively low penalty on non-
compliance by individual sources.
   The inadequacy of  the current regulatory system
is rather widely recognized, and gains in recognition
with each further thrust towards comprehensive en-
vironmental management. This is not to say that a
great deal has not been accomplished with the current
approach.  This is particularly true in the  sense of
bringing about  a problem  awareness,  underscoring
the government's resolve to achieve an improvement
in the environmental quality, and setting the research
program on the proper course. As the problems be-
come more complex, however, as the societal prob-
lems become  more massive and evident, the realiza-
tion of the need for a more  analytical comprehensive
approach grows. As complexities  grow, so grow the
questions that must be  addressed. Should  there be
ambient  standards,  effluent  standards,  or  both?
Should health effects carry the same weight as other
ecological effects, can and should cost-benefit analy-
sis be used to set the standards, the date  of achieve-
ment, or both? Should standards be expressed as a
maximum  allowable  concentration over  a  specified
period, and if so with what frequency? Are multiple
pollutant standards  required,  and  how  will  goal
achievement be determined?
   Along with the realization of the inadequacy of the
simplistic direct enforcement approach to deal with
complex environmental management problems  goes
an awareness  of the accompanying inadequacy of the
needed  analytical tools. In order to specify a control
plan and an achievement schedule which  truly mini-
mizes  socio-economic  costs (e.g.,  minimizes  the
societal cost-benefit ratio),  it must  be possible to
relate that plan to species  stress  and,  therefore, to
ambient  quality. The  preferred method of doing  this
would be through the  use of stochastic physical-bio-
chemical models for both water and air which  ade-
quately  represent the probability  aspects  of local
through  regional transport   and bio-chemical  pro-
cesses. Although much attention has been given and
is being  given to the  development  of  such  models
and the required input data, neither is adequate at
this time. As a result, interim methodologies and ap-
proaches are  utilized,  which fall far short of being
able to adequately address the questions raised.  It is
certainly clear that  a  substantial effort  is needed in
the near term to address the highly impacted areas.
A major concern is felt,  however, lest actions taken
now utilizing  gross data and gross techniques  pre-
clude more correct solutions  being implementable at
a later date.
   A  final point of concern  to the environmental
manager is involved in the achievement of a regional
long-term plan of environmental control that meshes
well with the pressing short-term needs. Short-term
programs can be expected to have less stringent goals
than the long-term  ultimates,  and rely more on im-
mediately available controls than  on longer range
technological and  operational  fixes.  Environmental
pollution, however, is a  symptom of the intensity
and scale with which human activities are pursued in
the region. Each region has a natural "carrrying ca-
pacity" for  these  activities, which can be altered
significantly only over a long period of time.  For ex-
ample, the carrying capacity can be altered by tech-
nology (e.g., mass-transit to off-set the use of auto-
mobiles;  or pollution control technology)  by urban
design  and  land-use  planning,  and  by  resource
conservation measures, such as improved building
insulation and design.  Long-terd environmental pro-
grams in effect are increasing  this regional carrying
capacity  by  altering the basic nature of the region
and its socio-economic activities. On the other hand,
much of a  short-term program (e.g., transportation
controls) is simply reducing the intensity or  scale of
human activities,  within  a fixed  carrying capacity.
Ultimately,  every  region  must live within, and plan
for, a  finite  carrying capacity. In particular, this
means  that  social  and  economic goals  must be
matched  to the natural characteristics of the region
involved and the interaction and impact of one region
on another.
   In summary, then, the ability to effectively man-
age the environment comprehensively involves many
factors. First it must be managed over a region large
enough to permit the effective control of the opera-
tive pollutants. Second, it is necessary to determine
the  maximum permissible  environmental  stress  to
protect the effective health of the population  and the
underlying ecological  system.  In this  connection,
questions of social risks should be addressed,  and the
concept of total benefit considered. Third, the cost of
control plans must be  adequately known. Fourth,  a
maximum loading  plan  must  be  established which
permits a consideration  of source distribution and
intensity,  as well as the social costs of control. Fifth,
a long-term  plan compatible  with short-term needs
must  be evolved which,  if necessary, can  allow the
region to reach the  limits of  its natural  carrying
capacity.  These parameters, adequately treated, will
permit a  management plan to  be developed which
addresses the  ability  to  comprehensively  protect
against  the environmental impact  balanced with the
necessity for  society to remain viable.
  This  symposium obviously  will not provide an-
swers to all  of the questions raised, but will  allow
both countries to share the knowledge we have  both
acquired and explore what has yet to be done—it is
a beginning.

 Systems  Analysis  and Simulated  Mathematical  Modeling as  a
Methodological Basis for the Standardization of Anthropogenic
        Pollution of  the  Environment:  A Regional Approach
                                 Yu. A. Anokhin, Yu. A. Izrael
   1. One of the  serious negative consequences  of
man's activities (primarily economic), as is known,
is the  pollution of the environment,  the  scales  of
which grow rapidly, but which, nevertheless,  ought
not be considered a necessary satellite of develop-
ment  [1]. Anthropogenic pollution of the environ-
ment  occurred in the  course  of historical develop-
ment, and is a unique (albeit far from the best) type
of "exploitation" of natural resources—the air reser-
voir, natural waters, and soils.
   Scientists and specialists, while acknowledging the
social origin of the problem of environmental  pollu-
tion ought not, however,  limit themselves simply to
calling for new ethical standards to apply to  man's
relationships  with nature. Our  task is  to develop
effective, scientifically valid,  measures for dealing
with pollution, and preventing the occurrence of pos-
sible crisis phenomena. By "pollution" let us under-
stand that we mean the  input into the environment
of toxic substances that  can be  harmful to people's
health, as well as of any other substances that could
have  undesirable  effects  on biogeocenosis and  on
materials, and this includes excess heat, noise, and
radiation in the environment. In truth, impurities are
substances  (and radiation fields) found where they
are not supposed to exist (this is a modified version
of an old chemical rule).  It  would only be natural to
include here as well anthropogenic changes in land-
scapes deemed unfavorable, not only from an eco-
nomic, but from an esthetic  point of view as well.
   The possible effects mentioned here are of great
social, cultural, and  economic importance, and  all
must be taken into consideration when setting pollu-
tion standards, either in terms of the  conditions the
role of the "leading" object must be in so far as man's
health is concerned, the  effect it will have on pre-
determined  natural  systems   (biogeocenosis),  on
certain forms of flaura and fauna, or even on certain
   Moreover, and this is of utmost importance,  an
understanding such as this of  the pollution problem
will make it possible to  deal  with it  as one  of the
facets of the wrong, irrational  use  of  natural re-
sources, so that the approach to solving the problem
follows as the  antithesis: find ways to make intelli-
gent, "optimum," use of natural resources.
  2. A characteristic property of the "optimization"
problem under consideration is its internal contradic-
tion, its "multidimensionality," so to speak, some-
thing a goal-oriented function takes on when an at-
tempt is made to assign the corresponding extremal
  The overall goal, for example, is that of rationaliz-
ing the interaction between industry and the environ-
ment,  and  comprises the following  sub-goals, the
latter  in many respects contradictory: maximization
of physical production and  of  the productivity  of
labor,  and minimization  of  waste  products  and re-
jected  products. While maximum  physical  produc-
tion and consumption could be considered the  opti-
mum  so far as satisfying human  demands is  con-
cerned, this approach is not optimum, however,  from
the standpoint of intelligent use of  nature (nor, inci-
dentally, from the  standpoint of widely understood
social requirements). Natural resources are  suscept-
ible to multiple use, so  the unresolved problem is
"how  to make a  quantitative  comparison  of the
different social requirements because of the difficulty
in comparing the need for clean  air, and the esthetic
enjoyment of the  beauty of  nature, with the needs
for electric power, metal, and fish, and because of
the difficulty, in turn, of comparing  the latter  each
with the other" [2].
   It is obvious, therefore, that any  attempt to resolve
the problem of how to use  nature more efficiently
"in one fell swoop," by resort to optimization proced-
ures of the mathematical programming  type, let us
say, is an illusion. An informal understanding of the
concepts of "optimum" and  "optimization"  must be
reached by the use of intelligent, "meta-model" con-
siderations, and this approach has a decisive  effect
on methodology selection.
   3.  The development of the correct methodology
for standardization of anthropogenic pollution  is the

most  important condition,  and means,  for  dealing
successfully with  pollution. Systems  analysis,  and
simulated mathematical  modeling,  as  applicable to
relatively closed territorial-economic systems, can, in
our view, become  the instrumentality of the method-
ology for standardization on a regional scale.
   The very fact that environmental pollution is most
intensive within the limits of existing territorial-eco-
nomic regions is why regional introduction of stand-
ardization of anthropogenic pollution in accordance
with accepted criteria for rational use of nature is so
important.  It  seems clear that the only policy  that
makes any sense at this  time when developing these
criteria is that of a differentiated  approach to our
country's various  natural  systems  (to  the  biogeo-
cenoses, for example).  Some natural  communities
should be completely cut off from any interference by
man, and should be preserved in their natural form.
There are  others, however, that should be adapted
to human needs more decisively and intensively than
is the case at the present  time. It is possible  that
there are  intermediate types of  communities,  and
here we can permit ourselves  to experiment, bearing
in mind at all times, however, the  possibility of  un-
foreseen, negative, consequences.  A policy such as
this is optimum in the sense that it guarantees "maxi-
mum freedom of choice  for our descendants" [3].
   4.  We shall, in  this report, deal first (paras. 5 and
6) with some of the general properties of the systems
in the class under consideration, regardless  of con-
crete realization. We then (paras. 7-9)  will take up
in some detail certain methodological questions con-
cerned  with the standardization of pollution on a
regional scale, and will illustrate these considerations
by the  example of the Lake  Baykal region (paras.
   5.  As is known, the  general properties of such
systems, because  they  are "organized  complexity"
systems  [4],  are  given  theoretical  consideration in
general systems theory. The most important of these
properties  are openness  (interaction  with the  en-
vironment), the hierarchical nature  of the structure,
temporal changeability, and the attribute of control
inherent in  these  systems [5-8]. Of significance to
us is the fact that these general properties have made
it necessary to develop a  new methodology for study-
ing complex systems, the basis  of  which is systems
analysis and mathematical modeling, with its general
directionality that from analysis (understood to mean
the breaking down of the whole into all of its smaller
parts  and studying each  of  the latter separately) to
synthesis, and the elements of inadequacy and  lan-
guage polymorphism inherent  in this method [8,  9].
   6. This approach is neither a narrow, special dis-
cipline,  nor some sort of  mystery. It  is,  rather, a
multidiscipline,  quantitative method  for studying
complex systems when knowledge of them is incom-
plete, the purpose of which is to predict the behavior
of the system under changing conditions, and, in a
certain sense, to gain optimum control of the system.
System behavior is determined by its structure, and
by the interrelationships of its elements. The follow-
ing properties of systems of this class  are  intrinsic
   (1) they have  a great many variables  (of the
order of several hundred, or more);
   (2) the variables often have feedbacks;
   (3) the system  often has time lags, nonlinearities,
and even discontinuities.
   Equations describing a system such as this usually
are without analytical solution, and this is why it
becomes necessary to turn to experimental investiga-
tions  with mathematical  models and resort  to an
electronic  computer.  As  is known, the  Forrester
school has gathered a great deal of experience  in this
field  [11-13].  Forrester  [11] has made a clear
analogy between controlling a complex system and a
unique  method  of driving an  automobile, one in
which the  driver is blindfolded and follows instruc-
tion given  him by  an instructor looking out the rear
window (that is, on the basis of information  on the
road already traveled). Added to this is the fact that
the instructions, as given, contain  time  lags and
errors. Given  conditions such as these,  it is difficult
to overestimate the importance of an approach that
is based on systems analysis  and simulated mathe-
matical modeling,  primarily because this  approach
makes it possible  to predict possible system  states.
This,  in  turn, serves  to make system control more
effective, and behavior of the controlled system more
regular. This  approach can, in its general  outlines,
be said to comprise the following main stages  [ll[
   (1) the concrete question in need of an answer is
formulated. This is basic. Successful formulation of
the question is  possible  only if the situation, the
problem, and the purpose  of the research, are  clearly
   (2) a verbal (verbal-causal) model,  that  is, the
fundamental internal  and  external  relationships,  is
   (3) the verbal  model is graphed, and then is re-
flected as a mathematical model;
   (4) system behavior is computer simulated, and
the results  are  compared with  available  data on
similar real processes;
   (5) iterativeness of the process  is  determined.
Return to stage (2) if the representation in the model
of real processes is unsatisfactory.
   We can  obtain the required degree of adequacy of
the model  to the real system by repeatedly "fitting"
the model  as we perfect our knowledge to the sys-
tem's  arrangement. And the statement of the problem
[(1), above]  can be  modified  as  a result of such
computer  "experimentation."

  7. Let us  now  turn  to the methodological  ques-
tions of pollution  standardization. There can be no
question  of the fact  that any program for dealing
with environmental pollution must include a complex
of sanitary-hygienic,  biological,  recreational-esthetic
requirements, etc., for environmental quality. Nor is
there any question of the fact that realization  of a
program  such as this has to  depend on social-eco-
nomic, cultural, and other factors, as well as on the
"level of lack of quality" of the environment that in
fact exists.  The present need for an optimum solution
of complicated  problems concerned with  pollution
standardization therefore should be obvious.
  Let  us note  that  existing  economic  and mathe-
matical methods of optimizing the use of production
resources cannot be applied directly to solving  prob-
lems concerned with optimizing  the use of natural
resources, and this is  particularly true when it comes
to optimum pollution standardization, because these
methods  fail to take into  account  the qualitative
specifics  of natural resources, which are production
factors, as  well  as the "bodies and forces of nature"
[15],  "the behavior"  of  which  is  determined by
natural laws that we know  nothing  about all too
often, unfortunately.
  8. Nevertheless, the economic approach, despite
all its very serious and well-known limitations,  must
and  can be  a  powerful lever to use in solving the
problems of  how  to  make  optimum use of nature.
This approach  is based on the concept of the repro-
duction  of natural  resources as one  of the   main
spheres of physical production  [16].  At the  same
time, the  central economic  problem  is  one  of  a
correct economic assessment of  natural  resources.
The concept  now used by Soviet economists to make
this  assessment is that of "closing  costs," so-called
[17, 18].
  9.  One  of the general laws of the behavior of en-
vironmental  pollutants  is that they tend to disperse.
Moreover, substances  that  are  reciprocally  con-
vertible,  particularly  when the resultant substance is
more toxic than the  original one, are of the utmost
importance.  It  is only natural,  therefore,  that the
general principle for the standardization and  moni-
toring of pollutants  should be  that of localization;
that is, the content of pollutants  in the environment,
and particularly their source, must be  standardized
and monitored. What follows from this almost self-
evident  assertion  is  the practically  important con-
clusion that  the presently universally accepted  prac-
tice  of  simply standardizing and monitoring the
threshold limit value  (TLV)  is not effective enough.
We  must  clearly  realize that there are  two closely
interrelated aspects of the  pollution standardization
and monitoring problem.  First  of  all,  there  is the
need to establish the  corresponding criteria, or  stand-
ards, for environmental quality (TLV types, or values
similar to them).  Absolute conformity  of environ-
mental quality  with  the established standard should
be the law, and should not  be violated.  Realistically,
however, the attainability of this state of affairs very
definitely depends on standardization and monitoring
the very sources of pollutants. This is why the stand-
ardization and monitoring of environmental quality
on the one hand, and of the sources of pollutants on
the other, are mutually complementary.
   10.  We shall, in this report, for purposes of greater
concretization, limit  ourselves to the consideration of
just  one  region,  that  of the Lake  Baykal  basin
(Figure 1). The region is one with quite high levels
of economic activity, yet has  a special  feature,  the
unique  cultural  and historical value of  the lake in
addition to its  high economic value. The need  to
foster the future economic  development  of this re-
gion and to utilize its riches, on the one hand, and the
unquestioned need to preserve the lake, together with
its fauna and flora in their original form on the other,
therefore does much to explain  the important role
this  region  has as a  unique  model  of  possible
judicious use of natural resources.
   There are  definite  methodological difficulties in
depicting the region as a relatively closed economic-
ecological system. Even the  statement of the problem
of depicting the region is contradictory because, as
has  been pointed out in the foregoing, an intrinsic
property of this type of system is openness.
   On  the  other  hand,  as  we  understand  it,  the
regional determinant  is  a  known homogeneity of
certain criteria  within the limits  of the region, such
as some combination  of physical-geographical, eco-
nomic,  administrative, social, and like properties, so
that the concept of  "boundary of a region" takes on
a  definite  meaning. In our  case the problem lends
itself to a relatively simple solution. The Lake Baykal
basin is a well-defined territory with accurately estab-
lished boundary, hydrologically speaking. The limits
of this  territory contain clearly distinguishable land-
scapes, composed in turn of  clearly distinguishable
systems of biogeocenoses.  And  although the land-
scape  and  the biogeocenosis are  essentially open
systems from the energy flow standpoint  (sunlight,
heat), as well as from the  standpoint of their inter-
relationships with adjacent  regions (for, in the final
analysis, this is what the evolution of the biosphere
is all about), it is important to  remember the con-
ception of the unity of biogeocenoses as elementary
"atoms" of the biosphere developed by V. I. Ver-
nadskiy and V. N.  Sukachev. The fundamental bio-
logical flows of matter and energy are locked within
the  limits of the biogeocenosis, so the biogeocenosis
boundary determinant is the condition that the mag-
nitudes of the flows across  the boundary be substan-
tially smaller than the internal flows. Thus it is  that
the  colossal Lake Baykal region "ecosystem", which
is a system of  relatively closed biogeocenoses, is it-
 self relatively closed.
   11. The economic subsystem of the  region under
review is extraordinarily "open."  It cannot be con-
 sidered closed,  even as an  approximation,  because it

           THE USSR AND THE IV

is obvious the level of economic activity, as well as
the  region's demographic features (population  and
its structure), depend  most heavily on  exogenous
factors, while  the flows of materials  and goods, let
us say, across  the regional boundary are of the same
order of magnitude as are the internal  flows.
  However, disregarding analysis of the relationships
between the region selected and other regions,  the
exogenous factors mentioned can be presented in the
form  of deterministic "forces" controlling the  de-
                                   velopment of the  economics, and thereby formally
                                   close the system.
                                      12. So  the region  is a  relatively closed  system
                                   consisting of interacting economic  and ecological
                                   subsystems. Figure 2 lists the main groups of factors
                                   describing the behavior of these subsystems  (paras.
                                   14-17 will contain brief comments on  these sub-
                                     We currently are in the  process of developing a
                                   simulated mathematical model of the functioning of
                                   the Lake Baykal region as an economic-ecological

             Economic subsystem

      1.   Exogenous factors

      2.   Population

      3.   Industry

      4.   Agriculture

      5.   Lumbering

      6.   Exploitation  of the lake

      7.   Other factors
                Ecological subsystem

        1.    Exogenous factors

        2.    Pollutants field

        3.    Biogeocenoses models

             (stability, resistability)

        4.    Reaction of biogeocenoses

        5.    Ecological damage

        6.    Other factors
system so we can predict the effect economic activity
will have on the region's ecological system. We firmly
believe that this  model,  initially of necessity very
rough, will  be a tool, as well as a powerful stimulus,
for future research, because it will help show up the
"white spots"  (gaps) in our  understanding of the
functioning of this very complicated system,  and thus
serve to formulate requirements  for the type, quan-
tity, and quality of the needed  data, the obtaining of
which must be organized. Participation in this work
of specialists in the  most varied of disciplines who
seldom meet as a rule is, in our opinion, extremely
valuable. This would include chemists, toxicologists,
hydrometeorologists,  medical  personnel, hygienists,
biogeocenologists, industrial workers,  and economic
   The development of the  model,  and full-scale re-
search, forming  two  continuous, interrelated flows,
will become the scientific base for valid decisions on
how  to standardize  anthropogenic pollution  on  a
regional scale.
   We cannot provide any details on the work we are
doing since it has only just  begun, but would, never-
theless, like to  share with you some fundamental
considerations, and to discuss some of the concrete
approaches we have planned for solving the  problem.
   13. A source of pollution in the regional  approach
to  pollution standardization can  be  an individual
chimney, a plant, a  city, or even a whole economic
region, depending on how detailed one wants to get,
that  is to  say, what "degree  of resolution"  of  the
problem is desired. The sources of pollution in the
production-branch approach are individual types of
production, or even a branch as a whole. The  im-
mediate task confronting us is investigatory in nature,
and involves the use of the simulated mathematical
model of how the region functions to make a com-
parison of the different anthropogenic sources of pol-
lution in terms of the degree to which they are harm-
ful  to the environment. Our sources of "pollution"
will be:
  (1)  large cities;
  (2)  industrial plants;
  (3)  individual,  nonlocalized types  of  economic
activity (animal husbandry, fishing, shipping, lumber-
ing, and the like).
  A model such as this must be dynamic, naturally,
so the comparison will result in approaching a solu-
tion to  a task of  higher order, that of comparing
various  alternative  programs for  the economic  de-
velopment of the territorial economic system under
review,  and making recommendations for the selec-
tion of  what would, in some way, be an  optimum
variant. It seems clear that the solution of the prob-
lem will involve the  need to combine the regional
and production-branch approaches if the solution is
to be responsible and concrete. The general arrange-
ment of the solution  of  this problem can be repre-
sented in  the form shown below (Figure 3).
   14.  Now let us make a few brief comments on the
economic and ecological  subsystems  in  the Lake
Baykal region.
   The Lake Baykal region's economic subsystem is
growing rapidly and is extraordinarily dynamic. We
have selected two sectors in the subsystem, the demo-
graphy and  the national economic, for discussion.
The group  of exogenic factors describes  all those
external planning  and economic  "forces," inclusion
of which  makes it possible to close the system (para.

           Sources of
           pollution and
Transport of
soil, natural
Reactions of
to pollution
Evaluation  in
terms of
                              FIGURE 3.  CLOSED CHAIN PROBLEM SOLUTION
   The demographic sector  of the economic sub-
 system can be described in broad outline as follows.
 Regional development  and population are very  ir-
 regular, and overall are  well down on the scale. Mean
 population  density is well below that for the  Soviet
 Union. Immigration from other regions in the coun-
 try, as well as natural growth, are increasing regional
 population. The distribution  and dynamics of the
 in ban  and rural  populations  are  not  the  same
 throughout the region, and in fact are determined by
 the  special features of economic development.
   The  national  economic   sector  describes  the
 region's own  economy, the basis of  which is well-
 developed industry (with its timber felling and saw-
 mill branches, as well as branches of heavy and light
 industry, and  power  engineering, having an  im-
 portant place  in the structure), and diversified agri-
 culture  (different branches  of livestock  breeding,
 animal husbandry, and  plant production).
   Hunting and fishing have an important place in the
 region's economy.
   The group  of factors combined under  the  rubric
 "other factors" includes tourism, and  other forms of
   15. So, to deal with the problem we are interested
 in,   that of comparing  the different  anthropogenic
 sources of pollution  in terms of the damage they  do
 to the environment  (para. 13), let us look at  the
 economic subsystem as  a whole as  a  source of pol-
 lutants and  at  its effects on the ecological subsystem,
 and, in  turn,  look  at the ecological  subsystem  in
 terms  of its  effects on  the  economic  subsystem
 (Figure 2).
  The ecological subsystem is a hierarchy  of rela-
 tively closed land and water ecosystems (para.  10).
  As we  know, Lake Baykal is one  of the largest
 fresh-water  lakes in  the world.  Its  exceptional age,
 vast depths, uniqueness of its fauna and flora, and
 the  exceptional purity of its  water, all make  Lake
 Baykal stand out sharply from other lakes, and give
 it its special, unique, character  [19].
  This very uniqueness, as well as the fact that a
huge number (some 400) of rivers empty into the
 lake (and bring with their waters the pollutants they
contain),  makes  Lake Baykal's biome one of the
most critical links within the  region.  (We should
                   point out that a great many of the natural and cul-
                   tural values in any region obviously are associated in
                   some way with the natural water systems  [3], so that
                   in  this respect the  Baykal region is  a  typical ex-
                     The  Selenga is the largest river in  the basin. Its
                   drainage basin covers 60% of the total area occupied
                   by the  lake's basin.  The river is 1024  km in length,
                   with 409 km  within  the boundaries  of the Soviet
                   Union. The  upper  reaches of the river are in the
                   Mongolian People's  Republic.
                     Only one river, the Angara, flows out  of the  lake.
                     16. Irrational management of fishing  and sealing
                   (particularly the taking of too many seals, and over-
                   fishing  the  lake   without taking  reproduction  into
                   consideration), and  insufficient attention  to fish pro-
                   pagation, to  say  nothing  of polluting the  rivers
                   with the wastes from the timber  industry  and with
                   industrial runoffs  that cause breeding  grounds to
                   deteriorate, can do definite damage to Lake Baykal's
                   biome,  and in particular to the fish stocks and to the
                   Baykal seal (ringed  seal) population [20].
                     Change  in  the lake's chemistry, the result of
                   change in the  hydrological and  chemical conditions
                   of the lake's  most important tributaries, the Selenga
                   and Barguzin rivers, "caused by the development of
                   agriculture and livestock breeding, and by intensifi-
                   cation of the feeling of trees, and more  recently by
                   the dumping into the river of industrial and domestic
                   sewage," also can  harm Lake Baykal's biome [21].
                     "Change in the composition of organic matter of
                   allochthonous origin  attributable to human economic
                   activity such  as to increase compounds resistant to
                   oxidation, as well as various  organic toxicants that
                   can  be  the reason for the shift  in  the equilibrium
                   state of the balance  of organic matter in  the lake so
                   that bacteria  accumulate because their  decay is sup-
                   pressed," is cause  for alarm [22].
                    Efforts have been  made in recent years to restock
                   Lake Baykal with  fish. A number of farms have  been
                   built for the  artificial breeding of Baykal omul (C.
                   autumnalis migratorius), and steps have  been taken
                   to improve natural spawning grounds (timber rafting
                   in free  form  was  prohibited  along the Selenga and
                   its tributaries in 1972, for example). Studies of the
                   links between the  different ecological  and  morpho-

logical omul groups and the  heat and water condi-
tions in the lake, and  the unacceptability of estab-
lishing strict limits of any sort on fishing for a long
period of time, thus become highly important to near-
term planning for the reorganization of omul fishing
in Lake Baykal, to transferring it along the path of
spawning migrations [23, 24].
   So far as the ringed seal is concerned (the popula-
tion of which has been restored  and now numbers
some  68,000  [25]),  it is  worth  noting that the
world has very few lakes with ecosystems similar to
the  marine  ecosystem,  those  in  which   highly-
organized mammals complete the  food pyramid.
"The  biocenotic  and  economic importance  of the
ring seal is that it transforms the huge quantities of
small,  pelagic,  golomanka  [Comephorus—Baykal
fishes related to sculpins]  and gobies not now avail-
able to man (because they are scattered throughout
the body of water and do not concentrate in groups
large  enough to make their fishing economically ad-
vantageous), thereby converting them into a product
available in the form of edible and commercial fats,
meat, and, in particular, fur skins"  [25].
   17.  Another example of an important ecological
link in the region under consideration is the unfavor-
able change that has taken place in landscapes as a
result of economic activity. The problem we inherited
from  the past, that of moving  (eolian)  sands and
erosion (deflation) of soils in some regions of the
Transbaykae is particularly acute, leading as it does
to  the blocking  of populated areas,  rivers,  roads,
to the filling up of lakes and irrigation canals, and
covering fields, meadows, and forests. The  problem
arose many decades ago, and is the result of the de-
struction of vegetation, brought about  by continuous
concentrated logging, frequent fires, overgrazing of
cattle, as well  as ploughing up the light soils of the
broad steppes  (and  thus exposing earlier anchored
   Movement  of the sands, and the deflation  proc-
esses,  have intensified sharply in recent decades, and
this has increased the area of moving sands in the
south  of the Buryat ASSR several times over. 'This
outbreak of deflation is merely the reflection of the
increasing changes that are taking place in the land-
scape in the area because of anthropogenic factors"
   18. The examples of critical ecological links cited
confirm the obvious fact (para.  1) that dealing with
industrial and  domestic types of pollution is closely
interwoven  with the broader  questions  of  the  ra-
tional use  of  natural  resources  (land and forest,
in particular). The task of comparing different  an-
 thropogenic  sources of pollution in terms  of their
 "harmfulness," therefore, can  be  performed only
within the framework of a model broad enough to
include  the  questions  mentioned. Moreover,  the
 model should  contain  the whole approach to eco-
systems, something that is possible only when prob-
lems of a qualitative understanding  and of quanti-
tative modeling  of the  behavior  of  ecosystems  are
solved in terms of their common characteristics (sta-
bility, capacity to resist near the stability limits, and
the like). Then too, there may be individual elements
of the ecosystems, such as the omul population, the
ringed seal, and others, that could be of interest to
   The development  of  this model is a complicated
business,  and  that  is  why the  correct  structural
organization  of  the  model is so  important. This is
particularly true of the modular principle of its con-
struction,  when the  model consists of sectors and
subsectors that are relatively independent,  and only
loosely bound to each other, so that individual parts
of the model can be modified without the need for
substantial alterations to the rest of the parts.
   19. The remainder of our discussion will be purely
illustrative in nature because its purpose  is to ex-
plain the  approach,  without in any way pretending
that the description  of that approach is complete, or
   Anthropogenic  effects  on the  Lake  Baykal eco-
system reduce to the following types (or  combina-
tions of them):
   (a) the addition of organic and mineral substances
peculiar  to the lake (particularly  in quantities ex-
ceeding their natural fluctuations);
   (b) the addition  of toxic substances (not peculiar
to the lake);
   (c) the removal  of organic substances (fishing,
for example);
   (d) change in the makeup of the ecosystem.
Types (a) and (b)  can be combined under the ru-
bric  of "pollution," and in the main  are the  side
effects of economic  activity. Type (c) is one of the
forms of economic  activity. Type  (d) often is the
consequence of types (a), (b), and (c), but can be
independently important (when new forms are intro-
duced into the ecosystem, for example). Figure 4
shows the paths over which pollution can be carried
into  Lake Baykal.
   20. Elaboration of the scheme  shown  in Figure
 4  requires  that  individual  territorial  subsystems
 within the limits  of the  region under consideration
 be isolated.  In our case, the criterion for isolating
 subsystems is known homogeneity of the subsystems
 by degree of pollution and effect on Lake BaykaTs
   We have  isolated  22  territorial  subsystems, in-
 cluding Lake Baykal, within the limits of  the region
 on  the basis   of the available description of the
 region as an economic-ecological system  (Figure 1
 shows the numbers  of these territorial subsystems).
    Lack  of  space precludes  describing these terri-
 torial subsystems in  detail. We shall simply point

              Sources of

                                            Air Basin
Ground Surface
                       LAKE BAYKAL.
out the fact  that these subsystems include regions
that are the largest industrial centers, various hydro-
logical sections (sections of  the Selenga River), and
various regions around  Lake Baykal, and that they
are in addition to areas external to the region, and
to Lake Baykal itself.
   21.  Figure  5 shows  the  interaction between the
isolated subsystems as they affect Lake Baykal's eco-
system. Let  us explain the subsystems and  their
interaction (the numbers, are those shown in Figure
   0. Lake Baykal, the  object of the anthropogenic
effects in  the model  under consideration.
   1. external areas. The subsystem reflects the over-
all geophysical  transport of pollutants, and transport
from adjacent regions.
   Fallout directly into the lake, fallout on the water-
sheds of the  rivers in the Lake Baykal basin  and
subsequent transport into the  Lake, and pollutants
coming from the upper reaches of the Selenga River
(the Mongolian  People's Republic),  all must  be
taken into consideration;
  2-9. isolated sections of the Selenga River;
   10-12.  these  subsystems  describe  the  effect  on
Lake Baykal's ecosystems of human settlements and
industry in the region.  The  outlines of regions 10,
11, and 12 (the Baykal Cellulose Plant, the  Selenga
Cellulose-Cardboard Combine, and the city of Ulan-
Ude, respectively) have been  drawn to correspond
to the transport of pollutants as depicted in Figure 4;
   13-21.  these are the  land areas in the Lake
Baykal basin, and were  isolated because of a hydro-
logical tie  with some particular section of the Selenga
River,  and other rivers  in the  basin, as well as be-
cause of the relative homogeneity of the type of land
use (arable land, haymaking, pasture land)  and the
extent  of forest utilization.
  22.  Let us,  in addition to  the  territorial break-
down,  isolate within the economic-ecological system
           of the region, certain functional  subsystems  of in-
           terest to us:
             (1) human settlements,  industry, transportation;
             (2) resource utilization (the biome of Lake Bay-
           kal, forest and land resources);
             (3) recreation;
             (4) hydrology, and quality of surface waters;
             (5) ecological  and economic aspects.
             Let us now present the factors that describe quali-
           tatively the  interaction  of  these subsystems  in  the
           form  of  a  matrix (Table  1).  The matrix element
           with subscripts  i, j  (i is the row  number, j  is  the
           column number)  describes the output factors of the
           i'" subsystem with i  =  j, and  these are simultane-
           ously the input factors  of the j'" subsystem  (when
           i  =  j, the  element  presents the concise  content of
           the  corresponding subsystem).
             As may  be seen  from Table 1, the presence of
           diverse  (including  reverse)  interrelationships  be-
           tween these subsystems  makes the model extraordi-
           narily dynamic  (so  the  important  role played by a
           methodology that simulates modeling when investi-
           gating similar systems becomes  quite obvious, as we
           pointed out  in paras. 7,  13).
             A model such as this should  be "rotated"  suc-
           cessively for the individual territorial subsystems (in
           accordance with Figure  5). The result is an assess-
           ment  of the effect the various anthropogenic sources
           of pollution have on  Lake Baykal's ecosystem.
             23. In conclusion, let  us point out that the degree
           of spatial and/or functional disaggregation  we have
           adopted on a preliminary basis in the model can be
           insufficient  (or  excessive, perhaps  ?)  for  reaching
           substantive  conclusions.  We are assuming, however,
           that  the  modular principle we have adopted  for
           building the model is such that the necessary  degree
           of disaggregation, or aggregation, can be introduced
           in the future without significant rearrangement of
           the  structure of the model.

                        Table  1.   Interrelationships Between  Functional  Subsystems
1.  Human    settle-
ments,  industry,
2.  Resource  utiliza-
tion (biome of Lake
Baykal,  forest  and
land resources).
3. Recreation.
4.  Hydrology,   and
quality  of  surface
5.  Ecological  and
economic aspects.
1. Human settle-
ments, industry,
2. Resource utili-
zation (biome of
L. Baykal, forest
and land re-
3. Recreation.
4. Hydrology and
quality of surface
Population, level of
industrial activity,
intensity of trans-
Possibility of unfa-
vorable consequen-
ces (blocking pop-
ulated areas and
roads, shoaling of
Development o f
sanitation institu-
tions, road building.
Possibilities of de-
veloping the paper
and pulp industry.
Logging, plowing,
laying roads.
Use of fish re-
sources, sealing,
lumbering, land use
(hay-making, p a s -
ture, arable lands).
Man-hours on fish-
ing, hunting; tour-
ism, and the like.
Field of concentra-
tion of ingredients.
Development of
suburban rest
Perceived qual-
ity of the envi-
ronment. Sport
Space-time dis-
tribution of rec-
reational activi-
Field of concen-
tration of ingre-
Sources of pollution
(domestic, indus-
trial run-offs, pollu-
tion by shipping).
Pollution (eutrophi-
cation), soil ero-
sion, clogging of
rivers, regulatory ef-
fect of forests.
Sources of pollution
(coliform bacteria).
Transport of water
masses and pollu-
tants, self-purifica-
Public health, fu-
ture development
of industry, and
Fishing, shooting of
seals, scope of lum-
bering, pasture and
arable land areas.
Economic advan-
tage, capacity of
sanitation institu-
Development of the
paper and pulp in-
dustry, field of con-
centration of pollu-
5.  Ecological and
Regulating  effect of the ecological  and economic aspects on the  functional  sub-
                                                        Assessment  of the
                                                        ecological and eco-
                                                         nomic aspects.
   Finally, even the coarse degree of disaggregation
we have adopted will,  we hope, provide the answer
to questions of practical interest.


  1. Ye. K.  Fedorpv. Vzaimodeystviya obshchestva i prirody
    [The Interaction Between Society and Nature]. Gidro-
    metizdat., Leningrad, 1972.
 2. A. A. Mints. "Geographic Approaches to an Economic
    Assessment of Natural Resources." V kn: Ekonomiches-
    kiye problemy  optimizatsii  prirodopol'zovaniya  [In
    book:  Economic  Problems of the Optimization of the
    Use of Nature].  "Nauka" Publishing House, Moscow,
 3. D. Ehrenfel'd.  Priroda i, lyudi  [Nature and People].
    "Mir"  Publishing  House,  Moscow, 1973.  David W.
    Ehrenfeld, Biological Conservation,  New  York, 1970.
 4. R. Waterman. Teoriya sistem i biologiya [Systems The-
    ory and Biology].  "Mir" Publishing House, Moscow,
 5. O. Bertalanfi. Issledovaniya po  obshchey  teorii  sistem
    [Research in General Systems Theory].  "Mir" Publish-
    ing House, Moscow, 1969.
 6. F. Mesarovich. Issledovaniya po obshchey teorii sistem
    [Research in General Systems Theory].  "Mir" Publish-
    ing House, Moscow, 1969.
 7. B. S. Fleyshman.  Elementy teorii potentsial'noy effek-
    tivnosti slozhnykh sistem  [Elements of  the  Theory of
    the Potential Efficiency of Complex Systems]. "Sovets-
    koye Radio" Publishing House, Moscow, 1971.
  8. V.  V.  Nalimov. Logicheskiye osnovaniya  prikladnoy
    matematiki [Logical  Bases of Applied  Mathematics],
    Moscow State  University Publishing House, Moscow,
 9. I.  M.  Gel'fand.  "Interaction in Biological  Systems."
    Priroda, No. 6, 1969.
 10. Hamilton et al. Systems Simulation for Regional Anal-
    ysis. MIT Press, 1969.
 11. J.  Forrester. Industrial Dynamics. Cambridge (Mass.),
    MIT, New York-London, 1961.
 12. J.  Forrester.  Urban  Dynamics. Cambridge (Mass.),
    MIT, 1969.
                                        13.  J.  Forrester.  World Dynamics.  Cambridge  (Mass.),
                                            MIT, 1972.
                                        14.  A. A. Lyapunov. Problemy  kibernetiki  [Problems  of
                                            Cybernetics], 25. "Nauka" Publishing House, Moscow,
                                        15.  A. A.  Mints.  Mathematicheskiye  metody  v geografii
                                            [Mathematical  Methods in Geography].  Kazan', 1971.
                                        16.  M. P. Fedorenko. "Economic  Problems of the Optimi-
                                            zation of the Use of Nature."  In the book of the same
                                            name, "Nauka" Publishing House, Moscow, 1973.
                                        17.  K. G. Gofman. "Methodological Bases for an Economic
                                            Assessment of Natural Resources." V kn. Ekonomiche-
                                            skiye  problemy  optimizatsii  prirodopol'zovaniya  [In
                                            book: Economic Problems of the  Optimization of the
                                            Use of Nature]. "Nauka" Publishing House, Moscow,
                                        18.  "Basic Assumptions  in the Procedure for an Economic
                                            Assessment of Natural Resources in Mass Planning and
                                            Design Calculations" (project). V kn. Ekonomicheskiye
                                            problemy  optimizatsii prirodopol'zovaniya  [In  book:
                                            Economic Problems of the Optimization  of the Use of
                                            Nature].  "Nauka" Publishing  House,  Moscow, 1973.
                                        19.  K. K. Votintsev. Gidrokhimiya ozera  Baykal  [The Hy-
                                            drochemistry of Lake Baykal].  Irkutsk, 1963.
                                        20.  B, Buyantuyev.  K narodokhozyaystvennym  problemam
                                            Baykala [National Economy Problems of Baykal]. Ulan-
                                            Ude, 1960.
                                        21.  A. I.  Metseryakova.  "The Chemical  Runoff  of Rivers
                                            in the  Lake Baykal  Basin."  V  kn. Krugovorot  vesh-
                                            chestva i energii  v ozerakh i vodokhranilishchakh  [Cir-
                                            culation of Matter  and  Energy in  Lakes  and Reser-
                                            voirs]. Listvenichnoye naBaykale, 1973.
                                        22.  K. K. Votintsev, G. I. Popovskaya.  "The Circulation of
                                            Organic Matter  in  Lake  Baykal."  V kn.  Krugovorot
                                            veshchestva i energii v ozerakh i vodokhranilishchakh
                                            [In book: Circulation of  Matter and Energy in Lakes
                                            and Reservoirs]. Listvenichnoye na Baykale,  1973.
                                        23.  I. P. Shumilov. "A Procedure  for Calculating the Num-
                                            ber of Omul That  Are  Spawned."  V kn.  Krugovorot
                                            veshchestva i energii v ozerakh i vodokhranilishchakh
                                            [In book: Circulation of Matter and Energy in Lakes
                                            and Reservoirs]. Listvenichnoye na Baykale, 1973.
                                        24.  N.  S. Smirnova-Zalumi,  V.  V. Smirnov.  "The Omul
                                            Population in  the  Ecosystem  in  Lake Baykal." V  kn.

                                                         Krugovorot veshchestva  i energii v ozerakh I  vodo-
                                                         khranilishchakh  [In book:  Circulation of Matter and
                                                         Energy in Lakes and Reservoirs], Listvenichnoye na
                                                         Baykale, 1973.
                                                     25.  V. D. Pastukhov. "The Role of Seals in the Ecosystems
                                                         of Continental  Water Expanses (the Lake Baykal Ex-
                                                         ample)."  V  kn. Krugovorot veshchestva i  energii v
                                                         ozerakh i vodokhranilishchakh [In book: Circulation of
                                                         Matter and  Energy in  Lakes and  Reservoirs]. List-
                                                         venichnoye na Baykale, 1973.
                                                     26.  "Wind Erosion  of Soils and Measures to Deal With It."
                                                         Trudy  Buryatskogo instituta yestestvennytkh nauk, No.
                                                         9, 1971. Ulan-Ude.
             AND TRANSPORT OF POL-

     A Comprehensive  Environmental Analysis  of  the  Upper
      Potomac Estuary Eutrophication Control Requirements
                                       N. A. Jaworski *
  In the United States of America, lakes, rivers, and
estuaries are being subjected to increasing threat of
eutrophication. Some examples of ecosystems in the
U.S.A., that are currently experiencing euthrophica-
tion problems are Lake Erie, Lake Mendota, Lake
Washington and the Potomac Estuary.
  The eutrophication  process  is  a natural  phe-
nomenon. However, man has greatly accelerated the
rate of eutrophication mainly by the increasing dis-
charge of  nutrients  from  municipal and  industrial
effluents and the  increasing use of agricultural  ferti-
  To comprehensively  analyze the environmental
aspects of the eutrophication problems in the U.S.A.,
the following questions are being addressed:
   1. What is the current trophic status of the lakes,
rivers, and estuaries? How significant is the eutrophi-
cation problem?
  2. Which nutrient(s)  is causing this rate of eutro-
  3. Can this  accelerated rate of eutrophication be
decreased? If so, where should the emphasis of the
control program  be placed?
  In  this paper is presented a summary of the com-
prehensive environmental analysis of the eutrophica-
tion  problem in  the upper  Potomac Estuary. This
case study illustrates the type of analysis  that  is re-
quired to develop a control program for eutrophica-
tion. Applicability of this study to other water bodies
is also addressed.


   The Potomac  River  Basin,  with a drainage area
of approximately 38,000 square kilometers (km2),
is the second largest watershed in the Middle Atlantic
States. From its  headwaters on the eastern slope of
the Appalachian Mountains, the Potomac flows first
northeasterly and then  generally southeasterly some
644  kilometers  (km), flowing past  the  Nation's
Capital. The  Potomac  is tidal from Washington,
D.C., to its confluence with the Chesapeake Bay, a
distance of 183 km (Figure 1).
  The  study area includes the tidal portion, which is
about 60 meters  (m) wide at its uppermost reach
near Washington  and broadens to nearly  10 km at
its mouth. Except for a  7.5 m shipping channel and
a few reaches where depths up to 30 m can be found,
the tidal portion is relatively shallow with an average
depth of approximately  5.5 m.
  Of the  3.3  million  people living in the entire
basin, approximately 2.8 million reside in the upper
portion of the Potomac Estuary within the 7,300
km2 which  comprises the Washington Metropolitan
Area.  The  lower area  of the tidal portion, which
drains  8,300 km2, is sparsely  populated.
  The upper reach above Indian Head,  although
tidal, is essentially fresh water. The  middle reach is
normally the transition  zone from fresh to brackish
water.  The lower reach is mesohaline with chloride
concentrations near the Chesapeake Bay  ranging
from approximately 7,000 to  11,000 mg/1.
  The average freshwater flow of the Potomac River
near Washington, before diversions for  municipal
water supply, is 305 cubic meters per second (cms)
with a median flow of 185 cms. The flow of the Po-
tomac is virtually unregulated  and is thus character-
ized by extremely high and  flashy  flows often ap-
proaching 2,500  cms during flood conditions and 30
cms during droughts.


   Early historical observations of the water quality
conditions  include  reports that in the  later 1790's
President Adams swam in the  Potomac Estuary near
Washington,  D.C.  By  the 1860's  when Abraham
Lincoln was  president, the canals leading into the
Potomac Estuary, as well as the Potomac Estuary
itself,  often emitted objectionable sewage odors forc-
ing Mr.' Lincoln to leave the White House at night.
From  the year 1870, when the first sewers and cul-
verts were constructed, to the year 1938, when the
  •Director, Pacific Northwest Environmental Research Laboratory, U.S. Environmental Protection Agency

                                 ZONE I

                             WOODROW WILSON BRIDGE

                                                        KILOMETERS BELOW
                                                         CHAIN BRIDGE
                                                PINEY POINT
10     20

                      FIGURE 1. STUDY AREA

                                              Table 1
                                      Water  Quality Problems
                                      Upper  Potomac  Estuary
Kilometers Major Type
of River of
Reach Affected Pollution
Chain Bridge to Hains Point
Mains Point to Piscataway Creek
Piscataway Creek to Maryland
Anacostia Tidal River
Frequently high bacterial counts
Low-dissolved oxygen concentrations
Nuisance algal growths
Frequently high bacterial counts and
low-dissolved oxygen concentrations
Major Source
Overloaded sanitary sewers and
combined sewer overflows
Effluents from wastewater treatment
Nutrients in wastewater discharges
Combined and sanitary sewer over-
first primary treatment plant was built, almost all of
the sewage from the Washington Metropolitan Area
was discharged untreated into the Potomac Estuary.

  The burgeoning population growth in the Wash-
ington Metropolitan Area has compounded the water
quality management problem. The accelerated pop-
ulation growth has completely outstripped attempts
to provide adequate  facilities for wastewater treat-
ment. In addition, much of the growth has been un-
controlled in nature and location, and it is now diffi-
cut to provide adequate wastewater collection  and
treatment within the limited space available for such
facilities in the area.  Changes in composition of the
wastewater, mainly in the phosphorous content, have
also had a pronounced effect on water quality.

   Since the first sanitary survey  was made by the
U.S. Public Health Service in  1913 (1), the water
quality with respect  to bacterial  densities and  dis-
solved oxygen levels in the Washington Metropolitan
Area  has  been degraded as a result of the discharge
of either untreated or inadequately treated municipal

   The upper estuary has been divided into the four
reaches according to type and source of pollution
as itemized in  Table  1  and  shown  in Figure 2.
There are about 90 kilometers of the upper estuary
degraded  with the effects of  eutrophication being
pronounced in approximately 50 kilometers. In ad-
dition, the Upper Potomac Estuary,  including the
Anacostia Tidal  River, is subjected to  periods of
high  concentrations  of  sediment.  During  initial
studies of the estuary, major emphasis was placed on
the high bacterial and low-dissolved oxygen problems
(2)  (3). More recently, the nuisance algal problem
has also been included.

   The time frame of algal problem development has
been  developed from several studies as  summarized
by Jaworski et al. (4). As shown in Figure  3, there
have  been historical invasions of  nuisance  growths
in the Upper Potomac Estuary.
  From a review of data in Figure 3, it would appear
that  nuisance  conditions did  not  develop linearly
with  an increase  in nutrients. Instead the increase
in nutrients appeared to favor the growth and even-
tually the domination by a given species. As nutrients
increased further,  the  species in turn was rapidly
replaced by another dominant  form.  For example,
water chestnut was replaced by water milfoil which
in turn was replaced  by blue-green  algae, mainly
  The massive blue-green algal blooms, which have
occurred every summer since  1960,  appear to be
associated with large increases in phosphorus and
nitrogen loadings in the upper reaches of the Po-
tomac River tidal system (Figure 3). The blooms
have persisted  since the early 1960's although during
this period the amount of organic carbon from waste-
water was reduced by almost 50 percent when com-
pared to that discharged prior to 1960.
  Under warm temperature and low-flow conditions,
large  standing crops of this alga develop green mats
of cells. Chlorophyll  a  concentrations  range  from
approximately 50  to over 200  u g/1 in these  areas
of dense growth which at  times  extend over ap-
proximately 80 km of the upper and middle reaches
of the estuary. These  high chorophyll levels are 5
to 10 times those reportedly observed in other eutro-
phic waters by Brezonik et al.  (5)  and  by Welch
(6). During a dense bloom, the dry weight of cells
ranges from 10  to 25  mg/1  which is almost  twice
those reported from the lakes in Madison, Wisconsin.
  In  the mesohaline portion of the  lower reach of
the Potomac Estuary,  the algal populations are not
as dense as in the freshwater portion. Nevertheless,
at times large populations of marine  phytoplankton
(primarily  the dinoflagellates Gymnodinium sp. and
Amphidinium  sp.) occur producing what are known
as "red tides."

  The  concentration of nutrients  along the estuary
varies as a function of wastewater loading, tempera-

                                                     PERIODICALLY MODERATE
                                                     BACTERIAL DENSITIES.
                                                     LOW DISSOLVED OXYGEN
                                                     LEVELS AND BEGINNING
                                                     OF ALGAL BLOOMS
                                                     PISCATAWAY CREEK
                                                     NUISANCE ALGAL
               FIGURE 2. ESTUARY REACHES

      10,000 -
                                                                                       - 100.000
                                                                                       - 80,000
                                                                                       . 60,000
                                                                                       _ 40.000
                                                                                       - 20,000
                           1910      1920       1930      1940      1950

                                 FIGURE 3.  ESTUARY HISTORY
ture, freshwater inflow from the upper basin,  bio-
logical activity, and salinity. The annual distribution
of the various nutrient concentrations has been re-
ported by Jaworski, et al. (4), and the summer levels
are summarized in Table  2 for five  key  stations
along the estuary.
  In  the vicinity of the Woodrow Wilson  Bridge,
there  is an increase in alkalinity, total phosphorus,
NO* and NOa nitrogen, and ammonia nitrogen  with
a corresponding decrease in pH, all of  which can
be attributed to the  1.23 million m3 per day of waste-
water  discharged in the Washington Metropolitan
Area.  The  rapid  disappearance of the  ammonia
nitrogen  between Woodrow Wilson Bridge  and In-
dian Head and Maryland  Point is  caused by the
oxidation of NHs to NO2  + NO3 by the nitrifying
bacteria.  The  sharp drop in NO2  +  NO3 nitrogen
between  Indian Head and Maryland  Point is at-
tributable to the large uptake by  the  pronounced
algal  growths  in this area.
  A complete analysis of the nutrient sources in the
Upper Potomac Estuary has been made by Jaworski
et al. (4).  A summary of the major sources is pre-
sented in Table 3 for low, median, and high Potomac
River flows.
  When considering only the upper basin runoff and
wastewater discharges to the estuary as  summarized
in Table 3, it can  be concluded that  the order of
percentage  of nutrients controllable by wastewater
treatment is (1) phosphorus, (2) nitrogen, and (3)
  While the controllable  phosphorus  and nitrogen
percentages decrease at higher flows, these conditions
usually occur during the months of February, March,
and  April,  when temperatures  and algal  crops are
lowest.  Since  nuisance  algal conditions  occur pri-
marily in the upper or the freshwater portion of the
estuary,  the  higher  flow  effects are reduced con-
siderably by  the time the blooms are  most prolific
during the  months of July, August, and September.
  Under low- and median-flow  conditions, both
nitrogen and phosphorus are largely controllable.  If
allowances  are made for  atmospheric  contributions
of nitrogen,  only  an  approximate  200  kg/day  of
nitrogen could be added to the upper estuary, which
is less than 10 percent of the nitrogen  in the waste-
water discharges. Thus, during summer  months, algal
control by  management of nitrogen instead of phos-
phorus appears to be a feasible alternative.
   Using only 0.1  percent of the transfer rate, the
amount of carbon (CO2) potentially available from
the atmosphere was estimated to be approximately
431,000 kg/day  (4).  Moreover,  with the  upper
reach of the estuary well  mixed due to tidal action,

                                                Table 2
                                    Average Range of Concentration
                                           Summer Conditions
                                        Upper Potomac Estuary
Stations and
Kilometers from
Chain Bridge
Chain Bridge (0.0)
W. Wilson Bridge (19.5)
Indian Head (49.3)
Maryland Point (84.3)
301 Bridge (104.7)
                                                Table 3

                                   Summary of Major Nutrient Sources
                            Upper and Middle Reaches of the Potomac Estuary

                                            Low-flow Conditions
                                          (95% of time exceeded)
                        (Potomac River Discharge at Washington, D.C.=40 cubic meters/sec)

                   Median-flow Conditions
                   (50% of time exceeded)
 (Potomac River Discharge at Washington, D.C.= 185 cubic meters/sec)
  159,000             68              72,600             32
   18,100             40              27,200             60
    2,400             18              10,900             82
                    High-flow Conditions
                    (5% of time exceeded)
(Potomac River Discharge at Washington, D.C.= 1150 cubic meters/sec)
  680,000             90              92,600             10
  185,000             87              27,200             13
   10,000             47              10,900             53
 'Upper basin runoff: both land runoff and wastewater discharges in upper basin.
recruitment of carbon  from benthic decomposition
appears to be a significant source of inorganic car-
bon as well.  When all potential sources are con-
sidered, it appears that management of carbon  for
algal control is not a feasible alternative at the pres-
ent time.

   For water  quality   management  purposes,  the
Upper Potomac Estuary may be considered hyper-
eutrophic  when nuisance plant  organisms become
predominant as  it is now occurring with  the  blue-
green algae. Four major water use interferences have
been offered by Jaworski,  et  al. (4) including the
required  reduction in  the  algal  standing  crop  for
each of the conditions as shown in Table 4.
   The first  two are related to the  oxygen budget.
Studies have demonstrated that during  the summer
                               months  more ultimate oxygen demand is added to
                               the upper estuary as a result of  these algal growths
                               than  from the present wastewater discharges, though
                               this demand may not be fully exerted.
                                 The  aesthetic and recreational potential of  the
                               upper estuary is impaired by the extensive mats of
                               algae which cause objectionable odors, clog marinas,
                               and cover beaches and shorelines. The potential  use
                               of the estuary as a  water supply source could also
                               be impaired  because of possible  toxin  problems  as-
                               sociated with the blue-green algae.
                                 Of the  four  interferences, the highest reduction
                               percentages are  for  control of algal growths to pre-
                               vent  nuisance conditions.  From  the data in Table
                               4, a 75 to 90 percent reduction in  chlorophyll a con-
                               centrations will be required to limit chlorophyll levels
                               to approximately 25/ig/l, the concentration selected
                               as the desired upper limit for eutrophication control
                               in the Upper Potomac Estuary.

                                               Table 4
                           Subjectve Analysis of Algal Control Requirements
Water Quality or
Water Use Interference
DO Depression Caused by
Algal Respiration
Increase of Total Oxygen
Demanding Load
Recreational & Aesthetic
Nuisance Conditions
Indications of
mg/1 of DO below
mg/1 of Increase in
Ultimate BOD
Chlorophyll a
Magnitude of
Current Interference *
1.5 to 3.0 mg/1
15 to 30 mg/1
100 to > 250 ug/l
0.5 mg/1
5.0 mg/1
25 ug/l**
Required Percentage
Reduction of Current
Standing Crop
•Under nuisance-bloom conditions, chlorophyll a concentrations range from 100 to >2SO»g/l
** Average over entire water column.

  The desired nutrient criteria were developed using
data from: (1)  algal composition analysis,  (2) an-
nual nutrient  cycles and longitudinal profiles,  (3)
bioassay studies,  (4) review of historical data,  (5)
comparison  with a noneutrophic  estuary,  and  (6)
algal modeling. Each method was used independently
in the  development of a nutrient phytoplankton re-
lationship in the  Potomac Estuary.
  When investigating the role of nitrogen and phos-
phorous in eutrophication of the  Potomac  Estuary,
a detailed study of the movement of  these nutrients
was  made using  both  a real-time  dynamic water
quality estuary  model   (8)  and  an  average  tidal
mathematical  model (9). The dynamic modef was
expanded to predict  the concentration of chlorophyll
a based on  the  utilization of inorganic nitrogen. In
Figure 4, predicted NO2 + NO3, NH3 and chlorophyll
a  profiles are presented. The predicted maximum
concentrations conform  closely  to observed data in
both distribution and magnitude.
   From field  data, bioassay studies,  and mathema-
tical model runs, it was  concluded that the  standing
crop of blue-green algae can be predicted using the
nitrogen cycle.  This further  supports the  premise
that the nitrogen  availability appears to control the
standing crop. Similar methods also indicated that if
total phosphorus were in the range  of 0.03 to 0.1
mg/1, the desired 25/^g/l level of chlorophyll could
be realized.
   Based on the six independent methods of analysis
and the 25  fig/1 level of chlorophyll a,   nutrient
criteria were developed for  reversing  the eutrophica-
tion process occurring in the freshwater portion of
the Potomac  Estuary as shown in  Table  5.  Since
there  are  over  5.0  mg/1  of  inorganic carbon
in the estuary, even under maximum bloom  con-
ditions, no criterion for  carbon could be  established
at the present time.
   The lower values  of these ranges are to be applied
to the freshwater portion  of the  middle reach and
                     Table 5
            Required Concentration for
             Eutrophication Reversal
Concentration Range
Inorganic Nitrogen
Total Phosphorus
    0.30-0.5 mg/1
    0.03-0.1 mg/1
to the  embayment portions  of the estuary in which
the environmental  conditions  are more  favorable
toward  algal growth. The  higher values  are more
applicable to the upper reach of the Potomac Estuary
which  has  a light-limited euphotic zone  of  usually
less than 0.60 meters.
   Since the growth of massive blue-green algal mats
is apparently  restricted  to  the  freshwater portions
and  dinoflagellates  are  often  encountered  in  the
mesohaline environment, no specific nutrient  criteria
have been  established for the mesohaline portion of
the Potomac Estuary. It appears that  if the afore-
mentioned  nutrient criteria are achieved in the upper
estuary, adequate control of the eutrophication proc-
ess in the lower reach of the estuary should  also be

   Initially  in  1969,  to  facilitate  the  determination
of wastewater management  requirements,  the upper
and  middle reaches of the estuary were divided into
three 15-mile  (24 km)  zones with similar physical
characteristics, beginning at Chain Bridge (see  Fig-
ure  1). This zoning concept allows for greater  flex-
ibility ih developing control needs.
   More recent  studies have suggested that  Zone  I
be divided into three subzones described as follows:
Subzone                    Description
I-a      Potomac Estuary  from Chain Bridge to Hains
         Point, a distance of 12.1 kilometers.
I-b      Anacostia tidal  river from Bladensburg,  Mary-
         land, to the  confluence with the Potomac, a dis-
         tance of 14.4 kilometers.
I-c      Potomac Estuary from  Hains Point to Broad
         Creek, a distance of 12 kilometers.

  fc€    75-






1.2 -



0.4 -

0.2 -
                                                             TEMP. = 27.5C
                                                             FLOW = 79.29 cms
                                               NH3 (PREDICTED)
                                                                 N02 + NO3 (OBSERVED)
                                                                      NO2 +  NOs (PREDICTED)

                                                                            SALINITY INTRUSION
                                 20          30         40          50
                                        KILOMETERS BELOW CHAIN BRIDGE
Discharges into tidal embayments were investigated
on an individual basis.
   Using the zone concept, total maximum loadings
for each pollutant were  developed  for  each zone.
Allocation of pound loadings for each discharge can
be  obtained by prorating the  zonal poundage using
various  bases  such as population, drainage areas,
geographical subdivisions, and others.

  Water quality simulations and  wastewater  treat-
ment  investigations were  made using  the  FWQA
Dynamic Estuary  Model  (DEM) and  the  DECS
III, a general purpose estuarine model. The  DEM
(8) is a real-time system utilizing a two-dimensional
network of  interconnecting junctions and channels
which permits direct inclusion  of  tidal embayments
in the flow representation. The model is comprised
of a hydraulic component that  describes tidal move-
ment and a quality component. The DEM includes
the  basic  transport mechanisms of advection and
                                                 dispersion as well as the pertinent sources and sinks
                                                 for each constituent. This model was used to simulate
                                                 water quality conditions on an hourly basis and to
                                                 determine zonal loadings under low-flow conditions.
                                                   DECS III is based on a time-dependent tidal aver-
                                                 age solution of  the basic mass  balance  equations
                                                 (9). This model was used to investigate seasonal
                                                 variations in the nitrogen and phosphorus distribu-
                                                 tions in the Upper Potomac Estuary.
                                                   Simulations  of phosphorus  discharges into the
                                                 Potomac Estuary were made using second-order re-
                                                 action kinetics with a deposition rate of 0.05 mg/day
                                                 at a temperature of 29 °C. The allowable phosphorus
                                                 loadings were determined based on maintaining an
                                                 average of 0.1 mg/1 of phosphorus (P) within Zone
                                                 I, 0.067 mg/1 (P) within Zone II, and 0.03 mg/1
                                                 (P) within Zone III.
                                                   For  investigating the  role of  nitrogen in water
                                                 quality management, a feedback system of the intro-
                                                 gen cycle was incorporated into the dynamic estuary
                                                 mathematical  model  similar to  that  proposed  by
                                                 Thomann  et al.  (10). The  model consists of six
                                                 possible reactions:  (1) chemical  and  biological de-
                                                 composition of organic nitrogen  to ammonia,  (2)

bacterial  nitrification  of  ammonia to  nitrite and
nitrate, (3)  phytoplankton utilization of ammonia,
(4) phytoplankton utilization of nitrite  and nitrate,
(5) deposition of organic nitrogen, and (6)  decay
of phytoplankton.


   Using the models and coefficients as described in
the previous sections,  zonal loadings were determined
for UOD nitrogen, and phosphorus (see Table 6).
The  loadings  presented  are  maximum  allowable
loadings for each zone, assuming that adjuacent zones
are loaded to their maximums.
   The increases  in  loadings for  the  lower  zones
mainly reflect the increase in the estuary's volume
and tidal transport. Since nitrogen and phosphorus
criteria for the lower zones are  more stringent, the
increase in nutrient loadings in  this area is  not as
pronounced  as for UOD.
   For the projected  1980 wastewater  loading con-
ditions, the  anticipated  percent  removal rates for
Zone  I-c would be approximately 93 percent  UOD,
96 percent  prosphorus  and 93 percent  nitrogen.
Since Zones II  and III do not currently receive as
much wastewater, the removal percentages will not
be as high.

1. Ultimate Oxygen  Demand
   The maximum allowable UOD loadings, as pre-
sented in Table  5 for the three upper zones  of the
Potomac Estuary, were developed for  low-flow and
summer  temperature conditions. During high tem-
perature periods, the effects of  nitrogenous  oxygen
demanding substances on the dissolved  oxygen bud-
get were determined  to be quite significant.
   Studies have shown that during very warm periods,
when  nitrification rates  are high, the nitrogenous
component of UOD  exerts 250,000 Ibs/day of oxy-
gen demand as compared to approximately 200,000
Ibs/day from the carbonaceous demand. During low
temperature periods, when  the  ambient water tem-
perature is less than  15°C, the effects of nitrification
on the dissolved oxygen budget  have been  shown to
be negligible.
   Based on these findings, it was recommended that
 (1) UOD  loading presented in Table 5 be  applied
only  under  summer  conditions,  (2)  the removal  or
oxidation of ammonia in wastewater discharges be
provided whenever the water temperature is above
 15°C, and  (3) a high degree of removal of suspended
 solids (a maximum of 15 mg/1 in the effluent) and
carbonaceous oxygen demanding material (a mini-
 mum of 90 percent) be provided on a year-round
 basis to prevent the  accumulation of sludge deposits
in the vicinity  of  sewage treatment  plant outfalls
during cooler  weather  and to maintain high DO
levels under ice cover.
                    Table 6
        Maximum UOD, Phosphorus, and
        Nitrogen Wastewater Loadings for
          Low-Flow Summer Conditions
Allowable UOD
2. Phosphorus and Nitrogen
  The loadings, as presented in Table 6, were estab-
lished for low-flow conditions. During these periods,
the nutrient contribution from the upper basin is in-
significant when  compared to that contained in  the
wastewater discharges.
  To  determine  whether  the nitrogen  and phos-
phorus criteria could be met under varying Potomac
River inflows and varying nutrient contributions from
the upper basin, an annual simulation was made of
conditions from February 1969  to September 1970.
This period was critical because a drought condition
occurred during June and July of 1969, and August
flows were over four times  above the average dis-
charge. Thus, both low and high summer flows were
   Mathematical  model analysis of the annual dis-
tribution of phosphorus in the critical algal growing
area showed  close agreement between the observed
and predicted phosphorus profiles  (see  Figure  5).
Also shown  in Figure 5 are the predicted  annual
phosphorus profiles resulting from year-round waste-
water phosphorus removal in the upper estuary, as-
suming: (1)  no  control and (2) 50 percent control
of the phosphorus loading originating in the Upper
Potomac  River Basin. From the data presented in
Figure  5, it was  concluded that both  (1) the adher-
ence to  maximum   allowable  phosphorus loadings
from wastewater effluents being discharged directly
into the estuary  (see Table  6) and (2) a 50 percent
reduction of the total incoming phosphorus  load
from the  upper basin, will be required if the recom-
mended maximum phosphorus criteria are to be real-
ized. In order to achieve a  50  percent reduction in
 the  present  phosphorus  load  from  the  Upper  Po-
tomac  River Basin, the  current overall wastewater
contribution  of  2700 kgs/day  must be reduced to
 less than 320 kgs/day.
   Because of the more stringent criteria, particularly
 in the  lower zones including longer  transport time,
 the possibility of recycling previously  deposited phos-
 phorus from bottom muds  and the  unpredictability

 of  phosphorus in various forms being  transported
 from the upper  basin, year-round  phosphorus re-
 moval at all wastewater  treatment  facilities in the
 Potomac River Basin was recommended.
   As presented earlier, the necessity for unoxidized
 nitrogen control  in wastewater discharges  to  main-
 tain a high dissolved oxygen content in the Potomac
 Estuary  was restricted  to that time of  year  when
 water temperatures exceed 15°C. When evaluating
 the need for annual nitrogen control to  prevent ex-
 cessive  algal  blooms,  controllability, duration  of
 nuisance blooms  and temperature become significant
   While spring blooms of diatom algal cells  have
 been observed, the major  nuisance blue-green  algal
 blooms of algae usually occur during the months of
 July, August, and September.  During these months,
 the controllability of nitrogen by wastewater  treat-
 ment is usually the greatest and the water  tempera-
 ture highest.
   Mathematical model predictions of inorganic nitro-
 gen concentrations in critical  algal growing  areas
 based on (1)  no estuary wastewater nitrogen re-
 moval,  (2) nitrogen removal  during  periods  with
 temperatures above  15°C  (April-November), and
 (3) year-round nitrogen  removal are presented  in
 Figure 6. For the nitrogen loading as given in Table
 6, the inorganic nitrogen  concentration of  less than
 0.3  mg/1 can  be achieved for drought conditions
 such as in June and  July. The abnormally high Au-
 gust Potomac River flow condition and resulting high
 upper basin loading caused the nitrogen  level to in-
 crease to approximately 0.5 mg/1.
   While it  may  be  desirable  to  maintain  nitrogen
 concentrations at or below the selected criteria at all
 times, the high flows from the upper basin during the
 winter and  spring months contribute high  nitrogen
 loadings  which  increase the nitrogen concentrations
 above  acceptable levels  regardless  of  wastewater
 treatment practices. In considering (1) that  nuisance
 algal  growths  occur mainly during  the  months  of
 July,  August,  and September,  (2)  that  seasonal
 nitrogen  removal  is generally  adequate for main-
 taining the desired nitrogen concentration during this
 time, and (3)  that  unoxidized nitrogen control  is
 required  only for warm temperature periods, it was
 recommended that nitrogen removal for algal  con-
 trol, as in the case of nitrogenous demand for oxygen
 enhancement, be limited to periods when  water tem-
 peratures in the estuary exceed 15°C.
  In developing the seasonal requirements, emphasis
 was  placed  on  maintaining a balanced ecological
 community structure in the upper  or  freshwater por-
tion  of the  estuary.  More research  efforts  in  both
transport mechanisms  and  nutrient algal  relation-
ships are needed  to determine  management require-
ments for the lower or saline portion of the estuary.
   The present cost of providing for additional waste-
water  flows  and treatment requirements from  the
year 1970 to 2020, including operation, maintenance,
and amortization cost, has  been estimated to be
$1.34  billion, with a  total  average  annual cost of
$64.9 million. The unit treatment processes assumed
include activated sludge,  biological  nitrincation-de-
nitrification, lime clarification, nitration, effluent aera-
tion, and chlorination.
   Reduction of  the initial capital and operation and
maintenance costs to a per capita basis are shown in
Table  7. The above summary, which does include
replacement  cost, indicates  that the cost of waste-
water  treatment in the Upper Potomac Estuary is
about $13 to $24 per person/per year. This expendi-
ture, which includes the cost of the activated carbon
process, will renovate the water to the chemical and
bacteriological levels to meet drinking water quality

   In the summary  of comprehensive  analysis  pre-
sented  for  the Potomac Estuary ecosystem, water
quality problems of eutrophication and low dissolved
oxygen were addressed. Limits were developed for
nutrients and ultimate  oxygen demanding materials.
For other estuaries  along  the North Atlantic Coast
the pollution stress  analysis would be very similar.
However, for some  lakes and rivers, the  compre-
hensive analyses can be signicantly different.
   To cope with this variation aspect of the eutrophi-
cation  analysis,  a National  Eutrophication Survey
was initiated in  1972.  The objectives of the survey
are as  follows:
   1. To  assess  the current  condition  of lakes and
impoundments (over 800) which have, or are being
threatened with, eutrophication problems.
   2. To  develop scientific rationale which can be
used in setting  and  revising water  quality criteria
for nutrients and developing eutrophication priorities
and policies.
   3. To assist federal and state governments in set-
ting nutrient control priorities and policies.
   4. To evaluate methods, including  analytical tech-
niques, that  can be used for lake classification.
   5. To assess the contribution of non-point sources
of nutrients  in varying geographic areas, and, on a
limited basis, relate the contribution  of nutrients to
land use management.
   In addition to the above,  research efforts in the
U.S.A. are  being conducted to develop eutrophica-
tion controls for freshwater and marine  environ-
ments.  Specific objectives of this research  are  to:


S  O.i.
n  0.4-1
                 	. PREDICTED
                                              1      II      I      I      I
                                             NO PHOSPHORUS CONTROL IN UPPER POTOMAC BASIN
                                             ASSUMING 50% OF PHOSPHORUS LOAD FROM UPPER
                                             BASIN IS CONTROLLED
        FEB    MAR    APR    MAY   JUN    JUL    AUG   SEP   OCT     NOV   DEC
                                 POTOMAC ESTUARY AT INDIAN HEAD
                                                                           JAN   FEB


I 2.0-
 3 0.8-

 - 0.4.

       FEB    MAR   APR    MAY   JUN    JUL    AUG   SEP     OCT   NOV   DEC
                             POTOMAC ESTUARY AT INDIAN HEAD
                                                                          JAN    FEB

                                         Per Capita Cost Projections
Average Population
Initial Capital
Cost/Time Period
Capital Cost/Person/Year
O&M Cost/Year
O&M Cost/Person/Year
Total Cost/Person/Year
 (1) develop an understanding of the eutrophication
 process,  (2) develop methods for monitoring eutro-
 phication conditions and  for predicting,  with  the
 use of mathematical models,  the impact of nutrient
 sources on  eutrophication,  (3) develop technology
 to control and reverse  eutrophication processes and
 (4) to establish the practicability  of using this tech-
 nology through pilot and demonstration scale appli-
   Our research efforts to date  appear to  indicate
 that the  approach to comprehensive environmental
 problems of the  Potomac Estuary is adaptable  to
 other  ecosystems.  However, the uniqueness of many
 of the lakes and rivers based  on morphological and
 limnological characterstics  requires  specific  analysis
 and data  interpretation. It  also appears that  control
 measures will be developed along the morphological
 and limnological basis for a given set of ecosystems.

  1. U.S. Public Health Service, "Investigation of the Pollu-
    tion and  Sanitary  Conditions of the Potomac Water-
    shed," Hygienic Laboratory  Bulletin No.  104, Treasury
    Department, February, 1915.
 1. U.S. Army Corps of Engineers, "Potomac River  Basin
    Report,"  Vol. I-Vol. VIII,  North  Atlantic  Division,
    Baltimore District, February  1963.
 3.  Davis, Robert K., "The  Range of  Choice  in  Water
    Management, A Study of  Dissolved Oxygen in the
    Potomac Estuary,"  Johns Hopkins  Press,  Baltimore,
    Maryland, 1968.
 4.  Jaworski, N. A., Donald W. Lear, Jr., Orterio Villa, Jr.,
    "Nutrient Management  in the Potomac Estuary," Pre-
    sented at  the American  Society  of Limnology  Sym-
    posium  on  Nutrients  and  Eutropbication,  Michigan
    State  University,  East  Lansing,  Michigan,  February
 5.  Brezonik, W. H.,  W. H. Morgan, E. E. Shannon, and
    H. D. Putnam,  "Eutrophication Factors in North Cen-
    tral Florida Lakes," Florida  Engineering and Industrial
    Experiment Station, Bulletin Series No.  134, Gaines-
    ville, Florida, August 1969.
 6.  Welch, E. B., "Phytoplankton and Related Water Qual-
    ity Conditions in an Enriched Estuary," Journal  Water
    Pollution Control  Federation,  Vol. 40,  pp. 1711-1727,
    October, 1968.
 7.  Lawton, O. W., "The Madison Lakes Before and After
    Diversion," Trans. 1960 Seminar on Algae and Metro-
    politan Wastes, pp. 108—117,  Robert A. Taft Sanitary
    Engineering Center,  Technical Report W61-3, 1961.
 8.  Feigner, Kenneth and Howard S. Harris, "Documenta-
    tion Report, FWQA Dynamic Estuary Model," FWQA,
    U.S. Department of the Interior, July 1970.
 9.  Thomann, Robert V., "Mathematical Model for Dis-
    solved Oxygen,"  Journal  of  the Sanitary Engineering
    Division, ASCE, Vol. 89, No.  SA5,  October 1963.
10.  Thomann, R.  V., Donald J. O'Connor, and Dominic M.
    DiTorro, "Modeling of  the Nitrogen and Algal Cycles
    in Estuaries,"  presented at  the Fifth International Water
    Pollution Research Conference, San  Francisco, Califor-
    nia, July 1970.
11.  Environmental Protection  Agency,  "National Capital
    Region Water and Waste Management Report," Wash-
    ington, D.C., April 1971.

                  The  Ecological  System Stability  Concept
                                         V.  D.  Fedorov*
  Complexity must be  considered  to  be the main
feature of biological systems. This is so because of
the variety of elements comprising the system and
the special features of their interrelationships (stress
and coordination). The impossibility of studying  all
the variables of very complex systems  inevitably in-
troduces  a  subjective  aspect  into  the  selection  of
some  of them, those the specialists deem most im-
portant  to an understanding  of  the nature of  the
phenomenon under investigation.  The a priori rank-
ing of system variables  according to  importance
(made consciously or  unconsciously)  therefore is
necessary  before the investigation of biological sys-
tems of any complexity  can be undertaken.
  The imposed necessity of operating with a limited
number of variables when studying the integral prop-
erties  of very complex systems precludes the estab-
lishment of simple cause-effect types of relationships
between the different properties of biological systems.
This is what has given rise in biology to the point of
view that  the whole is greater than its component
parts, so that the properties of the  whole cannot be
studied effectively after the whole has been broken
down into parts to study the properties of the latter.
This approach has led  to the concept of the exist-
ence of special biological laws  that cannot be ex-
plained by resort to the positions of the strict prop-
ositions of such sciences as physics and chemistry.
This point of view is quite productive today, because
research in  the integral properties of biological sys-
tems that reflects  the face of  the systems, their ap-
pearance, fate, and coordination, has been moved
up  on the agenda.

1. Characteristics  and types of biological systems
   Let us define  a biological system  as an object
capable of  forming negative entropy, the  integral
properties of which are the result of the interaction
of the parts of which it is formed. Let us now dis-
tinguish the following integral properties as primary
in biological systems:
   (a) complexity, determined by the diversity of the
elements  involved, and their  interrelationships, as
well as the  stress on  the interrelationships in  the
   (b) autonomy, which determines the special  fea-

  •Motcow Sute Unlveriity, Moicow
tures of the position of the system at subsystem levels
within the limits of a larger system;
  (c)  reliability, which determines  the probability
of processes taking place in the system, and of the
temporal maintenance of the constancy of its prop-
  (d) stability, which  determines the capacity of
biosystems to withstand external disturbing  effects,
while at  the same  time  preserving  the system's
"face," which is determined by its past history.
  There  are objective  reasons  for  the subdivision
of biological systems  into three groups according to
the differences in the system of regulations governing
their behavior (Fedorov,  1972):
   (1) a-type biological systems with central control;
that is a subsystem whose regulatory  link with any
element is stronger than the link between such ele-
ment and any other, taken arbitrarily.  This category
includes all animal organisms  with central and vege-
tative nervous systems;
   (2) p-type biological systems with "passive" con-
trol (Milsum,  1964), which  can include  plant or-
ganisms with their humoral regulation;
   (3) r-type biological systems with "random" con-
trol, which can include all  ecological systems not
carriers of a special behavior "program" in the DNA
molecules, as is the case in the first two groups.
   It is only natural that the importance of the integ-
ral properties  listed  will be  dixerent for difierent
types of biological systems.
   Thus,  such  integral  properties as reliability  and
autonomy, on  which the carrying out of  the "pro-
gram" is primarily  dependent,  will be of primary
importance for systems with a  "program"  (a-type
and p-type). At the same time, such integral  charac-
teristics as complexity and stability, on which their
fate is primarily dependent, that is, the capacity to
withstand  random "unprogrammed"  environmental
disturbances, will be  of primary importance for eco-
logical systems (r-type).
   It is useful, for purposes of convenience in justi-
fying methods used to  measure the integral  proper-
ties of ecological  systems, to separate the following
from among the "unprogrammed" disturbances of the
abiotic component.

   Environmental factors that interact with the living
 component of the system, that is, that have an effect
 on the system and experience a response from  the
 organisms,  should be included  among  the intrasys-
 tem factors (biogenic elements, for example).
   The second  group  of  environmental  factors is
 made up of so-called extra-system factors. These es-
 tablish the  conditions for  the existence of concrete
 ecosystems  within the limits  of larger system forma-
 tions, that  experience no  noticeable response from
 the biotic component  (solar radiation,  temperature,
 humidity, and salinity, for example).
   Finally, the third group of factors is made up of
 the so-called disturbing factors, those for which  the
 ecosystems  are poorly prepared (or not prepared at
 all) by the preceding  course of the  evolution of  the
 species, and by  the past history of the  formation of
 concrete  communities under concrete biotope con-
 ditions. They may include physically heterogeneous
 factors, but their distinguishing feature is the sudden-
 ness  (on  the geological time  scale) of the effect cre-
 ated  by change  in their intensity which is unusually
 abrupt for  the  system. This action can include  an
 abrupt change in the reserve of any "normal" chemi-
 cal element in  the locus  (for example, N  and P,
 which give rise to the problem of eutrophication), or
 of a  normally rare  element  (for  example, salts of
 heavy metals Hg, Pb, Cd) or, finally, the appearance
 of a  substance that  is "new" to life, that has been
 synthesized  by man (for example, DDT,  PCS and
 other pesticides).
   In fact, it is indeed the intensification of the dis-
 turbing factors associated with  the variety of forms,
 and with the reinforcement of the scales of human
 activity in the biosphere, that does much to explain
 just how important the problem of studying the sta-
 bility of natural  systems is today. Therefore, our sub-
 sequent elucidation of the material will  be  limited
 to a discussion  of certain of the general aspects of
 ecological system stability,  and to justifying methods
 used  to measure that  stability.

 2. Measuring the stability of variables
  A biological system has numerous characteristics
 that reflect  the  special features of its organization.
 These characteristics  can  be  considered as inde-
pendent variables of the system, and the need arises
in any study  of a system  to  continually estimate
their behavior in time  and/or space.
  The measurement of the stability  of an independ-
ent variable (Si) can be assumed to be the estimate
of the variation in  the unit values of a function
around a mean  in order to estimate  the temporal
change in individual independent variables. Stability
thus is a measure of the temporal inconstancy of any
function.  Such  estimates of Si can be  (Fedorov,
Bokolova, 1972) the mean values of the deviation in
amplitude, Ai [1], or the square of this deviation
A 2 [2], of the variable with respect to its mean value
       Xj is the value of the variable being measured
          at the time of measurement;
       n is the number of measurements when AXJ

       x"=ij x,.
   The index of heterogeneity of criterion distribution
that we have proposed (Fedorov,  1973), and which
is an estimate of the ratio of the mean geometric to
the mean arithmetic value of the variable, A>, [3],
A3 =
is yet another method for estimating Si. But regard-
less of the method used to  estimate the stability of
the individual variables, it can be shown that the set
of estimates  obtained forms a bimodal distribution
(Fedorov, Sokolova,  1972) when the values  found
for Si are ranked. One of the sets of estimates here
includes  the  indices  that  characterize the rate at
which  the process  occurs  (that is, the intensity of
the function), so these estimates can be expressed as
a time derivative. Let us call them functional esti-
mates, assuming that
   c  = .L
    f   n
  The second  set groups  the  estimates of  indices
that can be taken to be some result of the processes
(functions) at the time of observation, so these esti-
mates can be expressed as a time integral.  Let us
call them structural estimates, assuming that

  The most important functional characteristic of an
ecosystem is its productivity. The latter reflects the
rate  of formation of the  organic matter  (biomass)
by the individual species populations making up the
community. The most important structural character-
istic  of ecosystems is the biomass of the populations.
  This raises a question. How can the integral prop-
erties of a system be  evaluated quantitatively  from
numerous individual estimates  of independent  vari-
ables? Separation of the  indices of the ecosystem's
biotic  component into functional and structural  is
quite productive in finding an answer to the question
just  posed  because one can compare the  mean esti-
mates (or modal class positions) for the two sets  of
estimates obtained, that is, for S« and S,.
  It is readily apparent  that comparison of the  S*
and  S. estimates leads to the introduction of a certain
measure that characterizes the internal state of the
system, and this measure, as will be shown below,
determines the homeostasis of the ecosystem,

3. The homeostasis of biological systems
  The term homeostasis  was introduced initially  in
1932, by Walter Cannon  (Cannon, 1932)  to desig-
nate the mechanisms  that maintain the equilibrium
of the internal medium (blood sugar constancy, and
constant body temperature in warm-blooded animals,
for example), which latter is constantly being upset
by changing conditions in the  outside world and is
constantly  being  restored  by special internal mecha-
nisms with feedback action. These  mechanisms are
under the control of the  autonomic nervous system,
so are inherent in all living systems with a central
control subsystem; that is, a-type systems, or simply
  Much later  (Fedorov, 1970a),  while analyzing
the  organizational features  of  a- and r-systems, we
turned our attention to the existence of  a principle
difference between them. Thus, functional reconstruc-
tions of a-systems are designed to  maintain,  in  the
final analysis, constancy of the structural  character-
istics  (preservation  of the specific  external appear-
ance of the systems attributable to the functioning
of numerous mechanisms for regulating metabolism,
for example). Structural reconstructions of r-systems
were designed to maintain the constancy of the func-
tional characteristics.  Change in  the  ratio of  the
photophilic  to   thermophilic  forms,  and  of  the
thermophilic to  psychophilic  species makes it pos-
sible to maintain the constancy of the  production
characteristics  during  the  vegetative period  when
there  is a variation  in temperature conditions and
illumination. Thus, the presence of  ecological mech-
anisms that periodically  maintain  the  constancy  of
the functional characteristics of r-systems within pre-
dtermined boundaries makes it possible to apply the
concept of homeostasis to them after the concept has
been generalized and  formalized.
  We will take it that the concept of homeostasis can
be extended to include the mechanisms that maintain
the constancy of certain  characteristics because of
the inconstancy  of  others. This means that the oc-
currence of relatively stable properties in one part of
the system can  be  provided because of the occur-
rence of additional  instability in other of its proper-
  Thus homeostasis is a regulation mechanism, one
that provides for  temporal ordering  of  change in
system properties toward stability of groups of char-
acteristics with respect to processes (r-systems), or
to their  results  (a-systems). In ecological systems
in particular, the occurrence of an additional zone of
inconstancy is associated with change in the relative
abundance of individual  populations;  that is, with
change  in  the specific  percentage of biomasses of
species  while retaining the constancy of the overall
formation rate by organisms of a homotypic associa-
   The relationship
was used as the measure of the homeostasis (G) of
the living component of  an ecosystem in  the paper
written in collaboration with  S. A. Sokolova (Fed-
orov,  Sokolova,  1972).  However, for reasons  of
purely practical convenience  associated with intro-
ducing the normalization O^G^=1, the measure of
the homeostasis is best calculated from Eq.  (7) if
the value of Si is found by using Eq. (3) when using
the stability index
        G= 1--
when S
and when calculating  the  stability estimates  using
Eqs. (1)  and (2)
      G = l~~c~ when Sg
   Thus, in a living system a different absolute meas-
 ure  of variability can  be  attributed  to  a different
 variable, depending  on  the method selected for esti-
 mating Sj.
   This gives rise to a routine question. What is the
 cause of the variability in individual characteristics?
 There are two such causes.
   1. First, there are the internal causes  attributable
 to the special features  of the interaction of the ele-
 ments comprising the system. These reflect the laws
 of coordination of elements and of the interrelation-
 ships between them. Included,  for example, are the
 variations  in  the  numbers of two populations in a

 system whose mutual relations are  of the "prey-
 predator" type. The most important  feature of the
 changes attributable to internal causes is their fluctu-
 ating nature; that is, their change with variable ampli-
 tude  and frequency within the limits of some region
 that is the norm under the system's usual conditions
 of existence.
   2.  Second, there are  the external  causes, attrib-
 utable to the special  features of  the action of dis-
 turbing environmental factors. These are capable of
 bringing about deviations in system properties speci-
 fied by the  variables that  will be beyond the limits
 of the norm.
   Thus, it is precisely the disturbing causes that raise
 the question of the permissible measure of deviation
 from the norm, within the limits of which the ecosys-
 tem will be  able to withstand external actions because
 of its property of eliminating their consequences as a
 result of the ordering state of affairs of the homeo-
 stasis mechanisms.  This capacity is what brings  us to
 the concept of stability as an integral characteristic of
 systems, expressed  by the capacity to withstand dis-
 turbances. Consideration of stability as the  mainte-
 nance of some norm for the properties, attributable
 in turn to the norm for the individual variables, per-
 mits posing the question on the plane  of establishing
 a permissible measure of deviations from the  norm of
 certain of its properties under the effects of concrete
 environmental disturbances.
   Then let  us define system stability as the permis-
 sible  (without risk of destroying the system) measure
 of deviations in specified properties of a system  from
 the norm, caused in some measure by  external dis-
 turbing actions. In this definition, system stability is
 established  first with respect to  a limited number of
 selected properties, properties which we will call the
 specified properties, and second, with respect  to  a
 series of concrete disturbing  environmental  actions.
 System stability in this case can  be judged in propor-
 tion to the deviations from the norm of the specified
 properties caused  by the disturbing measure of the
 external action. This approach permits us to use the
 quantitative estimates of stability to compare estimates
 characterizing, on the one hand, the measure of the
 disturbing actions and, on the other hand, the evoked
 measure of deviations of  the  specified  properties
from  the norm. This then gives rise to the  need to
establish not simply a  measure of deviation of speci-
fied system  properties but the  permissible measure
of the deviations which, in time, can be eliminated
by the system itself. This measure of deviations elim-
inated by the system is in fact the permissible meas-
ure, and this measure  must be considered the meas-
ure of stability of the entire system as a whole.
  In  concluding this section it seemed important to
us to turn our attention to the  idea of the link be-
tween the permissible measure  of  deviations in the
specified properties of a system and the measure of
the homeostasis.  The very idea of such a link is ex-
tremely  constructive,  because  the  measure  of the
homeostasis  was quite uniquely established  above,
whereas  the  question of the permissible measure of
deviations  (as  distinct from the idea of a link with
the measure of  the  homeostasis)   immediately ac-
quires acuity and the vagueness of the question con-
cerning "norm" and "pathology."

4. Invariants as indices of the stability of biosystems
   A conclusion as  to the instability of systems does
not follow, of course, from inconstancy of individual
variables (estimates of Si). The already generalized
interpretation of the homeostasis logically leads to
the invariant possibility. It is true,  let us stipulate,
that an estimate  in the form  of a mean [Equations
(4)  and (5)]  cannot be invariant, strictly speaking,
because here we are estimating some mean instability
of individual indices which are incapable of reflecting
the  more  integral  characteristics  of system state.
However, as a very rough  approximation, when the
Condition  O^G=constant is satisfied, the simplest
primitive form  of what we  have decided to consider
in the form of  an invariant turns out to be the same
mean  estimate  of the  stability of the functional in-
dices of an ecosystem.
   A  more typical  case of an  invariant,  when the
properties under  consideration in the norm are gen-
erally  temporally unchanged  (or invariant),  can be
attributed to a complex combination of consistently
varying  individual  variables. The  definition  "con-
sistently  varying" implies a strict observance of the
rules  for the coordinating  of functions, which has
been achieved using the autonomic nervous system in
systems with central control, as a result of which it is
easier  to find  invariants  for  a-systems  than for r-
   We thereby  arrive at a  more integral interpreta-
tion  of stability  (although  less constructive)  as the
temporal maintenance of invariant properties, thanks
to the combined, ordered cooperation of continually
changing individual system  variables.
   Let us define the  conditions needed for  the mani-
festation of invariant properties  in biosystems. There
are two such conditions:
   (1) the closed nature of the cycle of the elements
of a  stagnant  environment in ecosystems; (2)  the
constancy  of the instantaneous rate of change in
system entropy.
   Then,  in accordance with these  conditions, the
invariants of ecological systems can be:
   (a) the  constancy of the ratios between the syn-
thesis  and  decay reactions  of organic matter in the
system (in units of energy);
   (b) the  constancy of the ratios between the rates
of movement of individual elements through the links
of the  trophic chain, or even of the rate of individual

   (c)  the  constancy of the ratios of negative  en-
tropy,  forming  at  different trophic  levels in  the
   However, the ecosystem invariants  cited and pre-
dicted  on  the  basis  of  general considerations  are
difficult to  use in practice because  the determination
of their values  requires a great deal  of preliminary
experimental work,  and both necessary  conditions
are almost  never satisfied, or are not strictly satisfied.
   The concrete generalized indices that can be meas-
ured can be (a) within the limits of a single trophic
link, the BR* index  (Fedorov,  1972), where B is
the biomass, and R is the rate of its formation, or
(b)  within the limits  of neighboring trophic  links,
the BpBv index, which reflects the interaction between
predator (BP) and prey Bv).
   Equations based  on BR* and BPBV estimates  can
be derived  and the  following biologically reasonable
assumptions can be useful as the initial premises:

            = L
                                           system variants, postulating that the complication of
                                           the variants,  justified  by logical  premises, will bring
                                           them asymptotically close to the theoretically possible
                                           invariants of an ecosystem. A logically justified ex-
                                           ample of just such a complication of variants can be
                                           the indices BR*D and BR*D/lg W, where D is the
                                           information index of  diversity  (MacArthur, 1955)
                                           and W is the number  of species.
                                           5. Measuring ecosystem stability
                                              Once the basic concepts included in the definition
                                           of ecosystem stability have been  denned and con-
                                           cretized, we can move on to discussion of methods
                                           of estimating its total stability.  Diverse, and numer-
                                           ous, methods for this kind  of  estimate can be de-
                                           vised, of course. Several estimating methods that use
                                           the so-called coefficient of stability, which we shall
                                           designate x, are suggested below.
                                              a. The canonical method. If  we also attribute the
                                           possibility  of deviation from the  norm to  the dis-
                                           turbing source, then  the  measure of the disturbing
                                           action turns  out to be  precisely the measure of the
                                           deviation of an independent variable from the norm,
                                           that is,
B. = const
                                                   1*1 n -1
R*2 • B2   R*3 • B3
                            = const
                                   = const   (12)
 B* • B?
_   p
                       = const
   What must be  emphasized is  that the BR*  and
BpBv indices  are  not  system invariants in the full
sense of the word. We can only state that they reflect,
in implicit  form,  the  movement of  energy in the
system, and therefore can  be used.  It  therefore  is
more correct to call them (as well as the biomass and
productivity indices  which form  them,  incidentally)
                                                     Then  the  result of the action, or the system's re-
                                                     sponse according to the action in terms of the speci-
                                                     fied properties, Ax, may be expressed by the relative
                                                     deviation of a  dependent variable from the norm,
                                                     that is,
                                                     The  ratio of these magnitudes can be called the
                                                     coefficient of system stability
                                                          X =
                                            In the  ecosystem "norm," x will equal O when the
                                            "norm" of the action of the external factors is pre-
                                            served, as well as when the system's invariant  prop-
                                            erties are maintained by the mechanisms of homeo-
                                              b. The selective method of estimating the coeffi-
                                            cient of stability is based on the taking into account
                                            of the inhomogeneities in the distribution of the esti-
                                            mates of the actuating source and the response regis-
                                            tered by the system [see Eq.  (3)].
                                              Here it is assumed that the index of stability  S
                                            of the  variables being measured  and  the system

properties under consideration (variant)  is a suitable
measure for estimating inhomogeneity in the sets of
values for  the individual variables being compared.
In  other words, an implicit identity between  the
method  of   estimate  Ax   and   the   expression
(1 ~S    ) is assumed. This method avoids the need
for tedious work in estimating norms and measures
for permissible deviations in an ecosystem. Then
    x =
           ' S
              (A3)] act
where S,
       ,     is the index  of  inhomogeneity in the

distribution  of the estimates of variables,  as calcu-
lated using Eq. (3). It is important to note that the
estimate for one  of the variants to which we attribute
decisive importance  when  determining  system state
(for example, the estimate in terms of BR*D), serves
as the system response in this case. At the same time,
the estimate of the stability of only one of the inde-
pendent  variables,  to  whose  action  we attribute
system response,  also can be used as the disturbing
   c. A  variant of the selective method is the estimate
of the  coefficient of stability in terms of the  mean
values of the set of estimates, Si, equated to the dis-
turbing  sources and to "system  responses"
            1  -
                    'i (res)
Let us call this variant the exploratory method, one
used in studying the combined  action of disturbing
sources on an ecosystem.
  d. The three means method uses the mean values
of the  stabilities, determined by any of the methods
relating to the  estimates of  the  disturbing  source

(Sd) and  to system  state, Si and S., to estimate the
coefficient of stability,
   X= —	                         (19)
       i • o/.   \
            (A 3)

If the  equivalance of 1—S     and Sd is assumed,

a variant of the three means method is the estimate
6. Conclusion
  In  discussing the representation of stability  that
has been developed, let us turn our attention to what
are,  in  our opinion,  several pertinent features  that
give our constructions a  concrete nature.
  I. The first of them concerns the  division  of the
characteristics of an  ecosystem into  functional and
structural,  so that a quantitative measure  of the
homeostasis (G), can be introduced.
  II. The  same variable, but used in different re-
cording methods, can simultaneously be the basis for
obtaining the characteristics of the disturbing  source
(for example,  an increase  in the total  reserve of
nitrogen in the system, AN,  leading to eutrophica-
tion), a structural characteristic (the content  of dif-
ferent forms of nitrogen at the current moment in
time), a functional characteristic (the rate of change
in the nitrogen content in the  environment), and the
invariant characteristic (the rate of nitrogen circula-
tion in  the system).  This has  made  it possible to
clearly classify the  data obtained according to com-
pleteness, how obtained, how processed, and research
goals, which is a cardinal point in determining the
mean values of the sets of estimates of variables ob-
tained  (extra-system, structural,   functional,  com-
bined-variants, invariants).
  III. Of  principle importance  is the  assumption
that when  G = constant^O, all estimates  of system
variables (AyO are within the limits of the  norm,
so that the concept of system "norm" in terms of the
norm for the specified properties was concretized,
and the region of the norm was determined for the
external and internal factors (y± AyO, as well as for
the disturbing environmental actions (x±Axi).
  IV. It can  be  postulated that when G-»O, when
the condition  O

Fedorov, V. D., 1970a, "Special features of the organiza-
  tion of biological systems and the hypothesis of an 'out-
  break'  by a  species  in  a community," Vestnik MGU,
  Biological Series, No.  2, pp. 71-81.
Fedorov, V. D., 1970b,  "The biotic variety of a phytoplanlc-
  ton community and  its  production characteristics," Bio-
  logicheskiye nauki, No. 2, pp. 7-15.
Fedorov, V. D.,  1972, 'The  problem of  the complex in
  biology  and special  features  of  its resolution," Vestnik
  MGU. Biological Series, No. 6, pp. 30-42.
Fedorov, V. D., Sokplova, S. A., 1972, 'The stability of a
  plankton community and some characteristics of the en-
  vironment," Okeanologiya, No. 6, pp. 1057-1065.
Fedorov, V.D., 1973, "A new index of inbomogeneity in
  the structure of a community," Vestnik MGU, Biological
  Series, No. 2, pp. 94-96.
Cannon, W. B., The Wisdom of the Body, 1932, London.
MacArthur, R. H., "Fluctuation of animal population, and
  a  measure of community stability," Ecology,  No. 36,
  1955, pp. 533-636.
Milsum,  H, H., "The nature of living control  ssytenw,"
  Engng. /., Vol. 47, No. 5, 1964, pp. 34-38.

       Development  of Maximum  Permissible Environmental
                                       B. J. Steigerwald *

  Most of the discussion thus far in the Symposium
has focused on the development and selection of air
quality goals or standards.  Certainly this is a critical
decision. In selecting standards  we  determine  the
severity of the pollution effect as well as those whom
we  will protect. Equally important and often more
practical are  the decisions relative to how we will
meet the air  quality goal  or standard. The  conse-
quences of these decisions are often immediate and
are very visible and understandable to the public. Es-
sentially, the regulatory strategy or air pollution con-
trol scheme that is selected determines the distribu-
tion of the burdens of control, and their magnitude.
  (Tlearly, the regulatory strategy that is selected or
the maximum permissible environmental loading that
is permitted should be the most cost/effective pro-
gram for the attainment of the air quality goal. In
addition we should consider pollution control as ad-
ditional costs of doing business. Control costs should
be  paid by the consumer  who will benefit from the
cleaner air. For example, a community whose control
regulations force location  of power plants into rural
or  distant regions should pay a high enough rate for
electricity to  offset any environmental effects  in the
area where the plant is located. These may include
air pollution,  water pollution or effects of strip
   Although the challenge  is  simple and clear—mini-
 mize the ratio of costs to  effectiveness and distribute
burdens fairly—there are  many practical constraints
 in  the  development of  the optimum  regulatory
 strategy. These limitations  usually dominate the situa-
 tion and often preclude the  full use of the available
 analytical tools. Compromises must always be made
 to  account for lack  of data on air quality, meteor-
 ology, location of receptors and emissions.  Political
 factors also  must  be considered and these are not
 necessarily   compatible   with  technical/economic
 optimization.  Despite  these  limitations the  art or
 science of selecting a regulatory strategy is probably
 on a par with our  ability to set optimum  environ-
 mental goals. Also,  it must  always be kept in mind
that air pollution is only one small part of a much
broader system which should be  optimized. Other
considerations should include energy supply, trans-
portation, public health care, general economic well-
being, recreation, and environmental factors such as
garbage  disposal and water pollution. Most  often
these  factors cannot be  included quantitatively in
decision  models of air pollution regulatory strategy.
Often major compromises must be made with limited
quantitative analysis.

   For purposes of the current discussion, we will
limit  ourselves  to the rather narrow problem of de-
veloping  the  best  possible  air  pollution control
scheme or set of regulations to meet a well stated air
quality goal  or standard. Even within this narrow
perspective, there  are a wide variety of factors that
must be considered and analyzed.

Institutional Factors
   Organization of government and the availability of
resources often direct the general form of the control
strategy or limit the scope of the analyses.  These
include:  form  of  government-socialistic or capital-
 include: form of government—socialistic or capital-
 strong local control  programs; statutory authority—
 freedom provided in enabling legislation,  mandatory
 regulations or exemptions in basic statute; technical
 sophistication of the nation or local governments de-
 veloping regulations; resources available for surveil-
 lance and enforcement; and extent of public support
 for air pollution control programs.

 Nature of Pollutants
    The effect of the pollutant being considered and
 the severity of the effect must influence the nature of
 the control program. The effects spectrum that must
   •Director, Office of Air Quality, U.S. Environmental Protection Agency

 be considered is continuous.  The spectrum starts at
 public health and  ranges through  material  damages
 to esthetics and  on to nuisance effects such as visi-
 bility and odors.
   Where the potential effect is on health,  affects a
 large  segment of the population, and is serious, ir-
 reversible, and  acute, a stringent  control strategy
 must be applied. This would include both the severity
 of the control measures and their time of  application.
 Examples are beryllium, asbestos, and mercury, three
 pollutants recently classified  as "hazardous" in the
 United  States.  Source control for  hazardous pol-
 lutants is under the very restrictive Section 112 of
 the Clean Air Act. Section 112 dictates nationwide
 emission standards, compliance from 90 days to two
 years, and extensive monitoring and surveillance.
   Pollutants such as fluoride  whose effect is serious,
 but not  acute and which may not  affect large seg-
 ments of  the exposed  population,  may allow for
 slightly less priority on the time of application of con-
 trol measures. Therefore, more reasonable, longer
 term control options may be possible.
   Some effects may call for no control. Recently in
 the United States,  we determined that odor control
 would not be a nationally  manated effort.  Odor is
 deemed  a local nuisance and  control should proceed
 at a rate determined by local needs and desires.

 Selecting an Air Quality Strategy
   The scientific character of the pollutant is possibly
 the most critical factor in determining the nature of
 the control strategy. If there are  multiple  exposure
 routes,  air pollution control  strategy must  be  inte-
 grated into the broader effort and put into  perspec-
 tive with timing and intensity.
   Many pollutants such as CO, SO2 and total par-
 ticulates are  emitted directly. Their source/receptor
 relationship tends to be uncomplicated; air concen-
 trations can usually be related to sources in the same
 urban  area.  Several  pollutants that  are becoming
 very important, however, are formed in the atmo-
 sphere often  after  long transport distances. Atmo-
 speric  chemistry complicates  greatly  the  develop-
 ment of  an effective, equitable control strategy. Oxi-
 dants, for example, are formed by the reaction in the
 atmosphere of certain  organic compounds, oxides of
nitrogen  and sunlight.  The  reaction is complex and
can occur within minutes or over several days. Re-
cent data show  that this  is  not  strictly an urban
problem.  Concentrations of oxidant  greatly exceed-
ing the air quality  standard of 0.08 ppm one-hour
average  are  occurring in many rural  areas of  the
United States 100 or more  miles from major cities.
Reports  include 0.15 ppm  in Ft. McHenry, Mary-
land, which is located 120  miles from Washington,
 D.C.;  0.13 ppm  in Kane,  Pennsylvania,  which  is
 over 150 miles from Cleveland, Ohio; and 0.5 ppm in
 Indio, California,  located over  120 miles from  Los
 Angeles. Sulfate particulate matter, including sulfuric
 acid, also seems to  be  formed in the  atmosphere as
 the  result of the oxidation  of SO2 gas; only 2%  is
 particulate  sulfate.  The situation  is  very  complex.
 Current information in this case is not yet adequate
 to allow the selection of a workable national control
 scheme for  meeting  a sulfate air quality standard.
   The  sources of a pollutant, their distribution  and
 future growth patterns  are also key determinants of
 the  control strategy.  To  effect significant  control,
 large  industrial  sources  generally  install control
 equipment.  Area sources such  as home heating or
 automobiles often  require  basic  changes  in  fuel
 supplies, land use patterns or life style of the popula-
 tion. In dry,  windy climates  such  as  the  South-
 western  United States, wind-blown dust,  including
 that from farming and unpaved  roads, can be the
 major source of particulate matter and may preclude
 meeting the air quality goals with any air pollution
   A formal analysis of alternative control strategies
 that incorporates  many of these considerations re-
 cently  has  been  done in  the  United  States  for
 NO2.( 1) The analysis resulted in a significant change
 in the national NO2 control program. A  short sum-
 mary of the study might be illustrative of the value
 of a preferred control strategy analysis.
   After some initial confusion  related to the  selec-
 tion of measurement methods,  we determined that
 existing  levels  of  NO2 were not excessive in most
 U.S. cities. The primary objective of the NO2 analy-
 sis  was to determine an  equitable and efficient air
 pollution control strategy  that  would maintain  the
 annual NO2 standard of 100 /*g/m3 despite the rapid
 growth  of NOx sources. A proportional  model was
 used to simulate air quality data at five-year intervals
 out  to  1990.  The model used  current  air quality
 data, six categories of NOx sources (light, medium,
 and  heavy duty vehicles, industrial processes,  area
 sources,  and  electric  power plants), five  sets  of
 growth  rates for each source category, two levels of
 stationary source control, and five NOx  automotive
 emission standards. A proportional relationship was
 assumed between NOx  emissions and NO2  concen-
 trations. Annual  air quality  estimates and control
 costs were calculated for each strategy. Fuel penalties
 were also calculated for each level of  mobile source
  The NOx analysis summary report  recommended
 that the 1977  automotive standard of 0.4 grams/
 mile be revised to 2.0  grams/mile. In addition  the
report  recommended that more stringent  emission
control  be placed on new  and existing  stationary
  •See Attachments: Attachment 1 describes NO. Analysis; Attachment 2 illustrates a range of estimated air quality and control costs.

sources in regions with high  NO2 concentrations.
The recommendation  was  made  after  evaluating
ranges of air  quality,  and costs  that  included fuel
penalties.  As  a  result of the analysis, adjustments
are now being made to the national control program
for NO2 in the United States. Table 1 illustrates  an
example comparison of two  pollution  control strat-
egies for New  York City. Several other strategies not
shown were also compared.

   There are two general approaches to developing
an air pollution control strategy.  The first involves
simply  the widespread application  of reasonably
available  control technology. The second involves
an air quality management program,  usually over a
relatively  small area such as a city, to balance emis-
sion control with air quality needs.

Control  Technology
   The control technology approach is the  more tra-
ditional strategy. A general problem is identified and
available  emission  control technology is applied to
control the problem. There is little attempt to vary
regulations to match air quality levels or to develop
long-range plans to maintain the air quality standard.
Formal analysis of  cost-effectiveness and cost-benefit
of alternative strategies is  not emphasized in this
approach. However, control is technically simple and
enforceable. Sources generally  know  unambiguously
their  control requirements and  can have confidence
that they will not  change continuously. The initial
successes  achieved  in St. Louis, Pittsburgh and Lon-
don were based on this form of control strategy.
   In the  Clean  Air Act of 1970, the U.S. Congress
generally  limited the control  technology approach to
new sources.  Section  111 of the Act,  New Source
Performance  Standards, requires all  new  major
sources of pollution to meet national emission stan-
dards  set by the  U.S.  Environmental  Protection
Agency.  These standards are based on application
of best demonstrated  control technology and take
into  account the  cost of such control  systems. Na-
tional emission standards are set for the lead content
of gasoline. Standards  are  also  set for new auto-
mobiles,  trucks,  and  aircraft.  Standards  are also
established for selected  sources  of  hazardous pol-
lutants. These  are based either on best technology
or on the degree of control needed in the most critical
situation in the country.**
   The control technology  approach  also is being
used increasingly  as a compromise solution when air
quality management  programs cannot be upheld be-
cause of lack  of data or inadequate  analytical tools.
Sulfur oxides and particulates are examples, espe-
cially in the vicinity  of large isolated  sources such
as power plants in very mountainous  terrain where
diffusion calculations are unreliable. The control of
oxidant in rural locations is another example.

Air Quality Management

   Theoretically, the benefits of the air quality man-
agement (AQM) approach are great.  Control is re-
quired only  where needed and  only  to  the extent
needed. Usually these benefits cannot be fully real-
ized because of practical limitations, but even if the
AQM approach is eventually discarded as the basis
for regulations, the AQM analysis will provide val-
uable  experience in setting  enforcement priorities
and in directing research and  data collection  pro-
   Air Quality Management is required by the  U.S.
Clean Air Act as the principal approach for the at-
tainment and maintenance of the national air quality
standards. The entire country has been divided into
247 Air Quality  Control Regions (AQCR). Control
region designations are based on considerations  such
as meteorology,  population density   and  political
boundaries. Each state  must submit a State Imple-
mentation Plan  (SIP) that outlines and  justifies  a
regulatory scheme to attain and maintain all of the
air  quality standards  in  every region or  part  of
Region within the state. The SIP's are very complex,
                                                Table 1
                              Comparing NOx Control Strategies (New York)
Automotive standard of
0.4 grams/mile
Moderate Stationary
Source Control
Automotive standard of
2.0 grams/mile and
Maximum Stationary
Source Control
Air Quality (ug/m*)
1977 1980 1985 1990
90 90 86 96
91 78 77 87
Control Cost (10° dollars)
1977 1980 1985 1990
144.8 276.0 457.0 510.1
128.7 194.7 320.6 377.4
Fuel Penalty (10° dollars)
1977 1980 1985 1990
67.6 134.9 212.2 227.9
60.5 92.8 132.1 136.7
  ••See Attachments: Attachment 3 lists New Source Performance Standard categories and pollutants; Attachment 4 lists dates for controlling
 Mobile Source Emissions; Attachment 5 illustrates Pollutant and Sources of Hazardous Emission Control.

 but each must include information on  current air
 quality,  an emission inventory, regulations that  will
 reduce current emissions enough to achieve the air
 quality standard  and evidence of enforcement  capa-
   The development of a complete  AQM program
 demands great technical sophistication, good under-
 standing of the pollutant and much data. A full dis-
 cussion  of  the AQM  is beyond the scope of this
 paper. It seems  appropriate, however, to  delineate
 some  of the data needed for a full  analysis and to
 describe the status of AQM techniques in the United
   Information on air  quality is vital to the AQM
 approach. The data must  be temporally and  spa-
 tially compatible with  the air quality standard, i.e.,
 hourly, daily or annual measurements and available
 for  key  receptor sites  and  in locations of expected
 maximum concentrations. Data must be available for
 enough  years  to  ensure that severe conditions  of
 meteorology and emissions  are  included.  Natural
 background (wind-blown dust, stratospheric ozone,
 organics  from vegetation)   contributions to urban
 levels must also  be  determined and  included in the
 analysis.  Finally, since the  AQM is so quantitative
 and so dependent on air quality, standard methods
 of  collection and analysis must be  developed  with
 known precision  and accuracy and the size  and sit-
 ing  of monitoring  networks  must be carefully  de-
 fined.  In the United States there are approximately
 4000 air sampling stations,  most using standard or
 equivalent methods  and operated by the  State or
 local governments. The data are sent four times each
 year to  a  national  data  system called  SAROAD
 (Storage  and  Retrieval of Air Data) for organiza-
 tion and evaluation.
   Source emission data are the next vital  part of the
 air quality  management analysis. The emission in-
 ventory  should include the magnitude and location
 of all important sources of the pollutant being eval-
 uated. Large sources should be specified individually
 along with information on stack height, existing con-
 trols, plant age and  economic viability. Area sources
 such as home heating or automobile emissions should
 be disaggregated  into geographical areas  compatible
 with the diffusion model being used. In  the United
 States, this may range from several square kilometers
 when sophisticated diffusion models  are being used
 to full counties (from a thousand to 30,000 square
 kilometers)  where the  simple proportional relation-
 ship between emissions and air quality is used. In the
 United States, approximately  seventy percent of the
 100,000 large point  sources (over 100 tons of emis-
 sions per year) and  all of the 3300 counties (as area
 sources) are included in the National Emission Data
System (NEDS).
  Data on the type and distribution of receptors that
may be affected by air pollution may also be neces-
sary in some types of air quality management analy-
 sis. The need to include receptors depends upon the
 type  of air quality standard that has been set. Cur-
 rently in the United States the health related standard
 must be met in all geographical areas by a date set in
 the basic legislation (1975 or 1977). Legally, the air
 quality standard basis for the control regulations and
 the latest time of application are uniform throughout
 the country. In practice, there is a priority  set on
 analysis, monitoring, surveillance, and enforcement
 that favors urban areas or other areas where sensitive
 receptors are  concentrated. Even  if allowed  by  the
 Act,  there are no usable damage  functions that re-
 late the magnitude of health  effects to changes in
 concentrations. Damage functions, therefore,  cannot
 be included in any air quality management models.
   An optimal control strategy cannot be selected
 without detailed information on control systems. For
 each  major source category, information for making
 air pollution control decisions must include effective-
 ness, availability (including timing) cost and social
 impact. Data  is fairly simple to collect for control
 systems  that  involve stack gas cleaning  equipment
 such  as precipitators  or  filters. When pollution con-
 trol is achieved through a  change in  the  manufac-
 turing process or  fuel  substitution,  we  find more
 difficulty in assigning a  cost  to  pollution control.
 Some  of the more recent control programs involve
 changes  to  the  transportation system  in  a city  or
 land  use planning which have a social impact that
 cannot always be stated in simple economic terms.
 Cost  comparisons  with more traditional  pollution
 control equipment may not be possible.
   The  heart  of  an  AQM  analysis is the source/
 receptor model that relates  emissions to air quality.
 In its simplest form this may be a proportional roll-
 back  model that  assumes, for example, that a 40%
 reduction in total SO2 emissions for the city will re-
 sult in a 40% decrease in air concentrations.  Unlike
 more sophisticated diffusion models, the proportional
 model does  not  account  for source  distribution,
 height of emission or meterological  conditions. (2)
   In  general,  diffusion models take into  considera-
 tion the pollution diluting capabilities of the environ-
 ment  (see  Table 2). The more dilution  that takes
 place because of wind, stack heights, or  distance
 between sources, the  lower  the ambient air concen-
 trations become. The "box" model, "gaussian plum"
 models, and the CO model are  examples  of more
 advanced diffusion models.  They allow one to pre-
 dict the spatial distribution of various concentrations
 of pollutants for a given day, or over some long time
 period, which  is not possible by proportional model-
   A  current  limitation  in  meterological  diffusion
 models is an inability to include the complex atmo-
 spheric reactions that both  form  and  destroy pol-
lutants. This is most  serious for photochemical sys-
tems involving hydrocarbon, oxides of  nitrogen and
oxidants. Extensive  research is underway and  an

                                               Table  2
                                           Diffusion Models
 Box Model

      Gaussian Model
         CO Model
C,=Cr exp [(0.87+0.98UPK1-Z/Z,)]
C,=ground level concentration, Cr=roof top concentration, Ci=leeward side of building concentration
Cv=wind side of building concentration (g m-1)
Q =source emissions (g sec'1)
u =average wind speed, ur= roof top wind speed (m sec-1)
h =mixing height (m)
d =\b [urban area] ** (m)
y =cross wind distance from plume axis (m)

                              PROJECTED AIR QUALITY
                                                              MEASURED AIR QUALITY
                  1970    1971     1972    1973    1974    1965     1976    1977
                                               CALENDAR YEAR

  Programs to  maintain  air quality standards gen-
erally allow for much more freedom of action and
imaginative solutions than control schemes  to roll-
back  pollution  to  attain the standards.  Since  the
emphasis is on new sources, evaluations can be made
of the effects of city planning, new mass transit sys-
tems,  effective solid waste disposal,  industrial siting
practices, economic incentives and emerging control
technology.  Theoretically,  programs  to maintain
standards should accommodate  themselves fully  to
balancing air quality  with economic  and population
growth. However, there is little experience with such
programs and no working  analysis  techniques  that
have widespread applicability. Since these are future
programs, there  is still time  for research to make
significant contributions.

  Efforts to maintain air quality in the United States
are a  complex program of activities, many of them
required by the Clean Air Act.  Current state emis-
sion regulations must be restrictive enough to achieve
the standards in the most polluted  areas; therefore,
where regulations  apply  state-wide, there  will be
excess control or "overkill" in all other areas. This
"overkill" will allow much growth of new sources to
be absorbed without violation of standards.  For ex-
ample, SO2 controls needed in Philadelphia will re-
duce SO2 levels in  surrounding counties by about
40%  (15 to 25 /ig/m3) even though they are  now
well  below the standard.  Special emission regula-
tions for new sources are a major part of programs
to maintain  the standard.  The  Clean Air Act and
EPA  regulations require nationwide emission stan-
dards for many new sources  including  automobiles
and trucks, gasoline additives, aircraft and all major
industrial processes. These help  ensure minimum air
quality  impact  of  future  economic and industrial
growth. In addition all new industrial and combus-
tion sources must obtain a  pre-construction approval
which can be given only if it is  determined  that the
air quality standard will not be violated in the vicinity
of the plant. Recently  these regulations have been
expanded to  include a pre-construction  review  of
airports, highways, shopping centers, amusement cen-
ters,  and other "indirect" sources that attract enough
automobile traffic to threaten the air  quality stan-
dard. Finally, a comprehensive analysis is being made
of needed maintenance programs for the more pop-
ulous Air Quality Control Regions in the  country.
These include projections to 1985 for emissions and
air quality and development of appropriate regula-
tions to ensure maintenance of the standards, includ-
ing consideration of land use and transportation.

                                                                    Table 3

                                                   Implementation Planning Progn
                                             PURPOSES:  (a)  Relate  emissions  of sulfur  dioxide  and
                                                              paniculate matter to ambient annual con-
                                                              centrations of the two pollutants

                                                          (b) Test regional control strategies of cost-
                                                              effectiveness  in  reducing ambient pol-
                                                              lutant concentrations
    Source Data
Management Segment

Purpose:  Create and
maintain emissions in-
ventory data for use
with other modules
    Air Pollution
  Diffusion Segment

Purpose:    Calculate
pollutant    contribu-
tions  from  individual
sources  to  preselected
                                                             PROGRAM MODULES

Control Cost Segment
Purpose:    Calculate
emission reductions &
costs  associated  with
applications  of vari-
ous control techniques
 Emission Standards
Purpose:   Determine
for each  source  the
most   cost-effective
control      technique
needed to achieve in-
put emission stds.
  Regional Strategies
Purpose:     Estimate
cost  of  control  and
ambient   air  quality
associated with imple-
mentation  of  a  re-
gional control strategy
                                                          FUTURE IMPROVEMENTS
                                             1) Update  pre-set  control technique information to reflect
                                                current control cost and technology
                                             2) Include,  in  the Air Pollution  Diffusion  Segment, the
                                                Samples  Chronological  Input  Model  which  has  the
                                                capability of calculating  short term  concentrations


   This paper has attempted to present some of the
conceptual considerations that we feel  are important
in developing optimum control strategies to  achieve
and maintain air quality standards. Strategy develop-
ment is a complex, very practical, and vital  part  of
the total field of air pollution  control. The  control
strategy and resulting regulations determine not only
who will control but also  the severity  of the neces-
sary control measures. No  attempt has  been made  to
discuss the detailed techniques of air quality manage-
ment analysis. Entire books have been written  on
many of them.
   Currently in the United  States, the concepts of air
quality management are used primarily to  guide the
development of control strategies. A full quantitative
analysis is seldom the  determining factor in setting
regulations because of institutional and political con-
straints and data limitations. Despite  many of the
unquantifiable  factors  associated  with air  quality
management,  improvements in models such as IPP
and development of new techniques similar to the
Plan Review Management System will possibly pro-
vide more objectivity in the selection of  future con-
trol strategies.


1. NOZ Analysis Report,  Office  of  Air  Quality Planning
  and  Standards, U.S. Environmental Protection Agency,
  September 21, 1973.
2. Proceedings  of Symposium on  Multiple-Source Urban
  Diffusion  Models,  U.S.  Environmental  Protection
  Agency, 1970.
3. Photochemical Smog, Proceedings of International Sym-
  posium  on Air Pollution, October 17, 1972,  Tokyo.
4. Air  Quality Implementation  Planning Program,  Vol-
  ume  1,  National Technical  Information  System—PB.
5. A Users Manual for the Sampled Chronological Input
  Model,  GEOMET,  Inc.,  Contract  No.  68-02-0281,
6, Validation  and  Sensitivity  Analysis  of the  Gaussian
  Plume    Multiple-Source   Urban   Diffusion  Model,
  GEOMET, Inc.,  Contract No. CPA 70-94,  November

               Attachment 1
         Description of NO, Analysis
           • COMPUTER MODEL
                 OF NO.
   -Light Duty Vehicles
   -Medium Duty Vehicles
   -Heavy Duty Vehicles
   —Electric Power Plants
   -Industrial Plants
   -Area Sources
   • COSTS
              Attachment 2
Ranges of NO* Air Quality Projections and Costs
             Air Quality (ug/m§)

             Costs (Millions $)
Los Angeles
San Francisco
New York
Washington, D.C.
Salt Lake City

                                               Attachment 3
                                     New Source Performance Standard
                                         Categories and Pollutants

                            Steam Generators                        SO* NOi, TSP
                            Municipal Incinerators                    TSP
                            Portland Cement Plants                   TSP
                            Nitric Acid Plants                        NOi
                            Sulfuric Acid Plants                      SOi
                            Asphalt Concrete Plants                   TSP
                            Petroleum Refineries                      SO* HC
                            Secondary Lead Smelters & Refineries        TSP
                            Petroleum Storage                        HC
                            Secondary Brass & Bronze Refining          TSP
                            Iron and Steel Mills                      TSP
                            Sewage Treatment Plants                  TSP
                                               Attachment 4
                               Dates for Controlling Mobile Source Emissions
Light Trucks
Heavy Trucks
*NA=Not Available
                                               Attachment 5
                                    Hazardous Emission Control—1973
Beryllium Plants
Ex traction'Plants
Ceramic Manufacturing Plants

Machine Shops	
         Mining & Milling
                       Mercury Ore Processing Facilities

                       Mercury Cell Chlor-Alkali Plants

Estimating the  Maximum  Permissible  Intensity of the Complex
   Effect of  Chemical  Factors in the Production,Municipal,  and
                         Domestic Environment on Man
                                        N. F. Izmerov *
  Investigations of the harmful effect of chemical
compounds on  living organisms when the toxins
enter primarily from  some one environment (air or
water, food, and so forth)  have now taken shape.
Approaches to the hygienic limitation of pollution
of individual  objects  in the habitat  have  been de-
veloped  in this  plan. At  the  same time,  we know
that the  same harmful substances can enter the body
simultaneously from the air in production areas and
in living quarters, from the atmosphere of populated
areas, from water and food, from clothing and shoes,
and so forth.
  And it  has been established that  emissions  from
the  production  of  aluminum,  cryolite,  and super-
phosphates settling on soil and water surfaces create
artificial geochemical  provinces with increased trans-
fer of fluorine to plants and animals  ecologically as-
sociated with man. There are individual microregions
1.5 to 2  km from a cryolite plant in which the fluorine
content  in the air was found to measure 0.46-0.85
mg/m3,  exceeding the maximum permissible concen-
tration  (MPC)  for  air by  a  factor  of 40-80.  The
fluorine  content in the soil 4 km from the plant ex-
ceeded the natural  content by a factor of 1.5-27.5.
The  harmful  effect of plant emissions on trees, as
well  as on the health of animals and man, has been
noted (Sadilova, M.S., 1964). The results of an in-
vestigation of individual groups in the population liv-
ing around aluminum and cement-slate plants where
elevated fluorine content is present in various environ-
mental objects revealed fluorosis in  varying degrees
of seriousness in children and in the adult population
(Audera,  A.  K., 1966),  as well  as change in the
thyroid  gland resembling  enthyroid goiter (Kharito-
nova, V. A., Perfil'yeva,  Z. V., 1966). Natural in-
vestigations  of  animals  (Lindberg,  Z. Ya.,  1965)
confirmed the prevailing role of production emissions
in the formation  of similar geochemical  provinces
with  increased  fluorine  content  in  environmental
  The population in agricultural areas absorbs a big
part of the pesticides in the course of everyday living
and not from the air in the work area, while working
in agriculture. The  specific content of DDT in food
products varies from 92 to 95%, in water 5%, and
in air 3%, of the total dose absorbed. The effect of
pesticides in a work area can be  characterized  by
its transitory nature, and by  its periodicity (L. I.
Medved', et  al.,  1971). The complex nature of the
effect on man is characteristic of a great many chem-
ical compounds.  One of the most widely propagated
production toxins, for example, is carbon monoxide,
yet is equally a domestic toxin. The products of the
incomplete combustion of natural and artificial gas,
and of other types of fuel in  buildings, vehicle ex-
haust gases,  and emissions from municipal and do-
mestic enterprises,  are the primary sources of  air
pollution,  along  with  emissions from metallurgical
industry plants, and the  like.  Signs of the effect of
carbon monoxide (increased blood level  of carboxy-
hemoglobin)  have  been  detected in 78%  of those
examined and living in apartments  supplied with gas
in individual microregions (Martynyuk, V. Z., Devy-
atko,  D. G., 1956).
  Hydrocarbons affect the inhabitants of oil drilling
areas during production  activities, as well as when
production is not taking place.  Changes in the cardio-
vascular system (lability of arterial pressure, changes
in the vegetative regulation of vascular tonus)  have
been  found  in  workers  in  refineries  refining high-
sulfur crude  oil, as well as among the  population
living in the surrounding  area  (Zagidullin, Z.  Sh.,
  However, it should be pointed out that  some sub-
stances  (carbon  disulfide, benzene, carbon tetrachlo-
ride,  and others, in particular)  are primarily indus-
trial toxins, whereas others, natural food  and fungous
toxins, for example, are primarily domestic toxins.
  A  toxicological estimate of the  complex effect of
toxins on the body  (upon simultaneous  intake from
  •Director, Order of the Red Banner of Labor Scientific-Research Institute of Industrial Hygiene and Occupational Dis«as«s of the Academy
at Medical Sciences of the USSR

different environmental objects)  cannot be identified
with the combined effect of several toxins, and pre-
sents very definite difficulties.
  The thrust of the attention given to resolving ques-
tions of setting complex hygienic norms for chemical
compounds naturally is concerned with threshold and
harmless levels of toxin effect on the organism upon
isolated admission. Experimental research in  par-
ticular has shown that  when there is simultaneous
admission of  chemical  substances  (12  nonelectro-
lytes) through the gastrointestinal tract and the res-
piratory organs at the MFC level or at the threshold
of chronic  effect, there  is summation  of  the effects
(S. M. Pavlenko, 1973). Ye. I. Spynu (1967, 1968)
has calculated that the summed quantity of pesticides
entering the body from different  environments at the
MFC level exceeds the harmless dose. He therefore
proposes establishing  a  harmless maximum permis-
sible dose of a drug for man, obtained by totaling
the maximum permissible doses  and  concentrations
in all environments, with consideration given to their
specific importance:
                    =  2 D
Dm is the maximum permissible harmless dose;
Di is the dose of pesticide in a food area ;
D2 is the dose of pesticide entering with the inspired air in
   the work area;
D3 is the dose of pesticide entering with the water;
Di is the dose of pesticide entering with the inspired at-
   mospheric air.

   Inherent in the realization of his proposals is the
difficulty that arises because of the  need to determine
the specific importance of the MFC in the different
environmental objects in order to calculate the maxi-
mum harmless dose.
   Also proposed for calculating the maximum harm-
less dose for  simultaneous admission of a single sub-
stance  into  the body  from different environments,
is the use of the principle of setting hygienic norms
as applicable to the combined effect of several chem-
ical compounds, the effect of which is unidirectional
in nature and  based on the additive effect  (A. I.
Korbakova et al., 1971). The use of a known formula
for the summed effect has been suggested for these

                    From prod.
                   MFC for prod

                 From atmosphere
                MFC for atmosphere

                    From water
                  MFC for water

                  Dose from food
                   POC for food
  The availability of norms for many pesticides, and
for certain other substances, in the air in work areas,
in the atmosphere,  in reservoirs, and in  food prod-
ucts,  as well as the use  of formulas for calculating
approximate levels,  today enables us to obtain some
idea  as to the summed content of substances in the
environments, and to recommend permissible quanti-
ties in each of them. At the same time, the differences
in the approaches taken  to justify the MFC  in dif-
ferent environments make it difficult to use the prin-
ciple  described. We know, for  example, that only
the MFC in the air in work areas and the mean daily
MFC in the air in populated areas can be established
from  the resorptive  effect (the maximum single con-
centration can be established  from the reflex effect),
and sometimes in terms of the toxicological criterion
for reservoir water for sanitary and domestic pur-
poses, and for food (with  a very small safety factor
= 100).  This  behavior  pattern can be,  and is, the
most  frequent dependency, but  it fails to take  into
consideration the possibility of a different effect for
the different paths over which admission can occur.
Toxicity, as well as  the danger of poisoning, depends
on how certain chemical  compounds enter the body.
Fluorodinitriles, for example, are only slightly toxic
when injected into the stomach  (LD60 =  997-2917
mg/kg) (Korshunov, Yu.  N., 1969), but are highly
toxic  when  inhaled and  the danger of developing
acute and chronic poisoning is very high  (these sub-
stances, when inhaled, are included among the highly
toxic  and dangerous compounds)  (LD50 =  62-67
mg/m3, Linich  = 1  mg/m3).
  It  would appear that aliphatic nitriles injected into
the  stomach undergo  enzymatic conversion  in the
liver and become less toxic by a factor of  100. The
neutralization of fluorodinitriles in the acirc environ-
ment  of the stomach also is of definite importance.
  The different nature of the effect stimulating toxins
have on the body when they enter over different paths
is important. Thus,  bromine is a specific stimulating
toxin when inhaled, and the  changes in the respira-
tory  system are of  decisive importance at  all levels
of its effects, and for any duration  (Ivanov,  N. G.
et al., 1973).  But  when  bromine enters the body
over other pathways, changes in the central nervous
system, in the reticular  formation,  in the cerebral
cortex (Krylov, O. A.,  1960; Z. Ya. Dolgova, Ye. G.
Dolgov,  1964),  and  in  the  thyroid gland  (Verk-
hovskaya, N. N., 1962)  come to the fore. Here the
problem  of fixing a complex norm is much more
  We also must pause to consider the important dif-
ferences that exist between the  actions of chemical
compounds that take place under natural conditions
upon  inhalation, and when they  enter via the gastro-
intestinal  tract.  In  the case  of  inhalation we most
often must deal with the  intermitten nature of the
effect, whereas  when admission is  over an  enteral
pathway the mode usually is  monotonic. It now has

been established that the intermittent mode of action
in some cases is more harmful to the body. The inter-
mittent  action  of such nonelectrolytes as  toluene
(Babanov, G. P.  et al., 1972), carbon tetrachloride,
methylene  chloride (I. P. Ulanova,  et al.,  1972),
trichloroethylene  (Lomonova, T. V., 1973), and a
number of pesticides  (Burkatskaya,  S. N.,  Mityu-
shina, V.  I.,  1968)  resulted in the development of
chronic  intoxication  and  failure of  the adaptive
mechanisms more rapidly than  their  monotonic ac-
tion. The hygienic significance  of the  variations in
concentrations of harmful substances  is different for
different toxins,  and is determined by their  proper-
ties. In particular, the  solubility of substances in
water and in  fats, the rate of saturation of the blood
by a substance,  and of its conversion  in the body,
the pathways and rate of excretion from the body,
and the ability to accumulate,  all play a significant
   Moreover,  long interruptions between  the effects
of most chemical substances can result in a reduc-
tion in  the toxic  effect  (Sidorenko, G. I.,  Pinigin,
M. A., 1971). At the same time, the biological effect
can  be  more pronounced  when  interruptions are
brief (N.  A.  Tolokontsev, 1960;  Lyublina,  1973).
These facts also  serve to  definitely complicate the
problem of establishing complex norms for chemical
   Data  that show the practical necessity for an inte-
grated approach  to establishing hygienic norms for
compounds that are all present at the same  time in
several  of man's  habitats are now at hand.  Experi-
ments proving, in particular, the inadequacy of the
MPC for the  fluorine in water, and ion in the atmo-
spheric air when the effect is complex (Petina, A. A.,
1967),  as well as in  the water, and in the air in a
work area when  the  effect is complex  (Avilova,
G. G., et al.,  1973), have been devised.
   A comparatively short biological experiment  (1
month)  showed that in the case of complex entry into
the body of the fluorine ion with water  and air at
concentration  at  the  MPC  level for  individual en-
vironments, the summed dose of fluorine in the body
causes  changes in many of the biochemical  indices
of the carbohydrate and mineral metabolisms, as well
as in the integral indices of body condition (Avilova,
G.G., etal.,  1973).
   We therefore can conclude that the problem of the
complex effect of chemical compounds as a whole is
not yet solved.  The  need  for  hygienic  norms for
chemical compounds entering the human body simul-
taneously  from different environmental  objects is an
urgent one, and requires the development of theoreti-
cal and  methodological approaches that will  provide
for detailed resolution  of this problem.  Today it ap-
parently is still too early to talk about a single norm
that will express  the  integral threshold of the pro-
longed effect  and  the integral MPC.
  The biological  magnitude of  an integral  MPC,
established using highly sensitive enzymological tests
to establish exposure, can  be an  important index
of the summed effect of a chemical factor for a num-
ber of substances, and this is in addition  to  the en-
vironmental estimate.
  The presence  of these substances in the environ-
ment  can be limited by making a  determination of
the  permissible  content of the products proper, or
of their metabolites, as well as by the state  of the
enzyme systems  in the biological media, or  of the
most  sensitive organs.
  It should be pointed out that the establishment of
two magnitudes  characterizing the maximum  permis-
sible quantities of a substance  entering through the
lungs and through the  gastrointestinal  tract must to-
day  be recognized as the most realistic  approach
when setting complex norms. At the same time, the
MPC for  a substance entering the  body  via the
respiratory organs must take into consideration the
possibility  of its  entering  the body  with  the  air
breathed in a production area and from the atmo-
  The MPC  for a  substance  entering through the
gastrointestinal tract should  take into consideration
entrance with water and food.
  Efforts such  as  these are particularly important
in the case of substances that  have far-reaching ef-
fects  (mutagenic,  embryotropic,  carcinogenic).
  Approval, in  the form of legislation, of hygienic
norms for  3,4-benzpyrene  in  individual  environ-
ments (the air in a work  area, atmospheric air, and
water) is a considerable step forward  in this regard.
At  the same  time, it has been shown that there  is
little difference  between the  minimum effective and
maximum nonblastomogenic  doses of 3,4-benzpyrene
for any of the pathways over which entry is had into
the body. The same blastomogenic  effect can be ob-
served, approximately, in the case  of  close summed
doses of  3,4-benzpyrene injected into animals in dif-
ferent  ways  (intratracheally, cutaneously, and  into
the stomach), as  well  as  when  the  data are con-
verted for man  (Yanysheva, 1972; Shabad, L. M.,
Sanotskiy, I, V., et al.,  1973).
  Thus,  despite the natural difficulties, an  integral
estimate of the maximum permissible intensity of the
complex  effect of chemical compounds on man from
different environmental objects  not only is necessary,
it is possible.

 1.  Audera, A. K.,  Vliyaniye promyshlennykh  vrednostey
   na sostoyaniye rotovoy polosti  [The influence of harm-
   ful industrial  conditions  on the condition  of  the oral
   cavity], Riga, 1966, pp. 34-37.
 2.  Babanov, G. P., Burov, Yu. A.,  Skolbcy, N.  A.,  Ver-
   khovskiy, L. G.,  Abramyan, G. G., Tritskaya, I. L.,
   Isakhanov, T.  M., Toksikologiya i  gigiyena produktov
   neftekhimii i neftikhimicheskikh proizvodstv [The  toxi-
   cology and hygiene of petrochemical products and petro-
   chemical production], 1972, pp. 32-45.

  3.  Burkatskaya, Ye. N.,  Mityushina,  V. I.  Gigiyena pri-
     meneniya, toksikologiya pestitsidov i klinika otraleniy
     [Hygiene of the use and  toxicology of pesticides and
     the clinical aspects of poisoning],  Kiev,  1968,  p.  698.
  4.  Verkhovskaya,  I. N.,  Brom v zhivotnom organisme  i
     mekhanism yego deystviya  [Bromine in  the  animal
     organism and the mechanism  of its  effect], Moscow,
  5.  Zagidullin, Z. Sh., Trudy  Ufimskogo institute gigiyeny
     truda  i  profzabolevaniy,  Vol.  16,  No.  2,  1965, pp.
  6.  Ivanov, N. G,, Germanova,  A. L., Pozdnyakov, V. S.,
     Klyachkina, A. M. et al., In Book: Adaptatsiya i kom-
     pensatsiya pri khimicheskikh vozdeystviyakh [Adapta-
     tion and compensation in the case of chemical effects],
     Moscow,  1973, pp. 75-92.
  7,  Kprbakova, A.  I., Shumskaya,  N. I.,  Zayeva,  G. N.,
     Nikitenko, T. K., Nauchnyye osnovy sovrem. metodov
     gigiyenicheskogo   normirovaniya  khimicheskikh  vesh-
     chestv v okruzhayushchey srede  [Scientific bases of
     modern methods for setting  hygienic norms for chem-
     ical  substances  in the environment],  Moscow,  1971,
     pp. 35-40.
  8.  Korshunov, Yu.  N.,  Toksikologiya novykh prom. khim.
     veshchestv, Moscow, No. II, 1969,  pp. 79-85.
  9.  Krylov,  O.A., Fiziohgiya zhurn. im. Sechenova,  Vol.
     52, No. 7, 1966, pp. 906-910.
 10.  Lindberg, Z.  Ya., Materialy 13 nauch. sessii Rizhskogo
     med. institute [Materials from the 13th session of the
     Riga  Medical Institute], Riga,  1965,  pp.  53-55.
 11.  Lomonova,  G.  V., Frolova,  I. N., Gritsevskiy, N. A.,
     Voprosy  psikhofiziologii  gigiyen.  analiza  trudovykh
     protsessov [Questions  of  the  psychophysiology  of  a
     hygienic analysis  of labor processes],  Moscow,  1967,
     pp. 57-67.
 12.  Lyublina, Ye. I.,  Kolichestvennaya toksikologiya  [Quan-
     titative toxicology], 1973.
 13.  Medved', L. I., Spynu,  Ye. I.. Burvy, V. S.. Belonozhko,
     G. A., Antonovich, Ye. A., Vrochinskiy, K. K.,  "Scien-
     tific  bases of  modern  methods for setting hygienic
     norms for chemical  substances  in  the environment,"
     Materialy vsesoyuznoy konf. 21-22  oktyabrya 1970 g.
     [Materials from  the All-Union Conference of October
     21-22, 1970], Moscow, 1971, pp. 13-17.
14. Pavlenko, S. M., Gigiyena  i  sanitariya, No.  1,  1972,
    pp. 40-44.
15. Avilova,  G.  G., Golubovich, Ye. Ya., Mal'tseva, N. M.,
    Pankratova, G. N., et al., In book: Adaptatsiya i kom-
    pensatsiya pri khimicheskikh  vozdeystviyakh  [Adapta-
    tion and  compensation in the case of chemical effects],
    Moscow, 1973, p. 92, 103.
16. Petina, A. A., Yernichnykh, L. N., In book: Flyuoroz i
    yego profilaktika  [Fluorosis  and its prevention], Sverd-
    lovsk, 1967,  pp. 50-55.
17. Sadilova,  M. S.,  Voprosy  gigiyeny  i  profpatologii i
    toksikologiya  [Questions of  hygiene  and   industrial
    pathology and toxicology], Sverdlovsk, 1967, pp. 25-26.
18. Sidorenko, G. N., Pinigin, M. A.,  "Scientific bases of
    modern methods  for  setting  hygienic norms  for chem-
    ical substances  in the environment," Materialy vseso-
    yuzn.  konferentsii 21-22 okt, 1970 [Materials  from
    the All-Union  Conference  of October  21-22, 1970],
    Moscow, 1971, pp. 13-17.
19. Spynu,  Ye.   I.,   Gigiyena primeneniya,  toksikologiya
    pestitsidov i  klinika otravleniy [Hygiene of the use  and
    toxicology  of pesticides  and  the  clinical aspects of
    poisoning], Kiev,  1968, pp. 103-108.
20. Tolokontsev, N. A., Gigiyena i sanitariya, No. 3, 1960,
    pp. 29-35.
21. Ulanova,  I.  P.,  Avilova, G. G.,  Bazarova, L.  A.,
    Mal'tseva, N.  M., Migukina, N.  V.,  Khalepo, A. I.,
    Eytingon, A. I.,  In book: Adaptatsiya i kompensatsiya
    organisma pri vozdeystvii khim. zagryuazneniy okruzh.
    sredy  [Adaptation and compensation by the  organism
    to  the effect  of chemical  pollution of the environment],
    Moscow, 1972, pp. 17-21.
22. Kharitonova, V.  A.,  PerfU'yeva,  Z.  V., Voprosy  pro-
    filaktiki i lecheniya zoba na  Urale  [Questions of the
    prevention and treatment of goiter in  the  Urals],  a
    collection of papers from the Sverdlovsk Medical Insti-
    tute,  Sverdlovsk,  1961, No.  34, pp. 20-25.
23. Shabad, L. M.,  Sanotskiy, I. V., Zayeva, G. N., Bruye-
    vich, T.  S.,  Katsnel'son, B. A., Yanysheva,  N.  Ya.,
    Shugayev, B. B., Gigiyena i i sanitariya, Moscow, No. 4,
    1973, pp. 78-81.
24. Yanvsheva, N. Ya., Gigiyena i sanitariya, No. 7,  1972,
    p. 87.

The Concept  of the Threshold Nature of the Reaction of Living
    Systems to External Actions and  its   Consequences  in the
      Problem  of Protecting the Biosphere Against Chemicals
                                        I. V. Sanotskiy *
  Legislative and other types of regulations of the
state of man's habitat, and that of the plant and ani-
mal  species  associated  with  him, the  toxicological
limitation  (hygienic normalization) of pollution of
the production sphere and of daily life, as well as the
derived practical measures of a technological or other
nature, depend in the final analysis on the resolution
of a fundamental question. Is there a threshold of
intensity of harmful effect of external factors,  or is
any intensity different from zero harmful? In other
words, can objective scientific facts be used as the
basis  for protecting the biosphere, or should sub-
jective decisions  (the "acceptable  risk" concept  on
the one hand, and  so-called "zero" pollution on the
other, and so forth) be used  to some extent?
  What must be emphasized is the  fact that one
generally is  not talking about the threshold of any
changes in living systems  as a result of external ex-
citation, but  of the  incidence of reactions beyond the
limits of  ordinary  physiological  variations observed
in the process of homeostasis, something that will be
taken up in  more detail below.
  A mathematical  description of the task is not the
subject of this report. The purpose of this report is
to set forth corresponding points of view, and  some
of the material used as the basis for for them.
  As is known, the occurrence of excitation, that is,
of a complex biological reaction to external action
in the form  of functional  changes, and the physico-
chemical processes that underlie them, is a property
of living  matter at  any stage  of  organization.
  The magnitude  of the effect  depends on the
strength of  the stimulation. Bowditch (1871)  dis-
covered the  "all" or "nothing" law, that is, there is
no  excitation  ("nothing")  when stimulations are
subthreshold, but maximum excitation ("all") is de-
veloped when the  stimulus is at threshold strength,
and does not increase when the stimulus is intensi-
fied. However, these propositions now are regarded
only as a rule,  because  local excitation, local re-
sponse, occurs in the stimulated  sector when stimuli

  •Inttltute of Labour Hygiene and Professional Diseases, MOKOW
are subthreshold. Nor can the "all" characterize the
maximum that the action potential of the nerve or
muscle fiber can attain.  According to another law,
the "law of intensity," the effect of the reaction is
greater the stronger the  stimulus causing it, over a
predetermined range of  intensity.  Even more com-
plex interrelationships, three and more phases, have
been described (Vvedenskiy, N. Ye.; I. V. Sanotskiy,
1950, 1970; P. V. Simonov,  1962). The magnitude
of the reaction, as is known, depends significantly on
the functional state of the reacting substrate.

Content of the Problem
   The question  of  the feasibility of establishing a
threshold of harmful effect for most types  of effect
of chemical compounds is not in doubt among most
authors.  However, this question is debatable when
it  comes to mutagens, blastomogens, and radiation
injuries. No decision was reached  at the symposium
organized especially for the discussion of this prob-
lem in February 1970, by the American Association
of Hygienists.
   At the same  time,  the threshold nature of the
effect of all harmful factors (including radiation, and
particularly chemical) can be proven theoretically by
starting from the basic differences between living and
nonliving  things  (the  constant  exchange by  the
organism of matter and energy with the environment,
the  continual  restoration by the  organism  of its
structure, and the  constant  adaptation to the en-
vironment, including those  similar to  itself during
the process of reproducing).
   The simplified expression
             Dy = Do — D«x — Dm«t
where Dy is the dose of toxin reaching the receptor;
Do is the dose of toxin introduced into the organism;
D« and Dmet are the doses of toxin excreted from the
organism, and rendered harmless as the toxin moves
toward the receptor, respectively, shows the threshold
nature of the effect [provided that (Dex + Dmet) is
not decreased in proportion to decrease in D0]. Data

 from an experiment with nonmetabolized and meta-
 bolized substances show that this condition  is ob-
 served. Indeed, only hypothetical substances abso-
 lutely not excreted  and  absolutely  not rendered
 harmless can reach the receptors without decreasing
 in quantity. There are no such substances.
   However, even if the receptors are considered to
 be isolated, so to  speak, from the integral organism,
 it will be  found that  simple fixation of the toxin by
 the receptor still does not mean a biologically signifi-
 cant reaction with it. For example, it has been shown
 in isolated human crythrocytes that fixation (includ-
 ing strong) up to  a certain limit by a cell membrane
 of lead ions does not lead to an increase in the yield
 to an incubation  medium of potassium and hemo-
 globin (Figure  1), according to data provided by
 Grigarzik  and Passow, 1958.
  Thus, the reconstruction of the molecules can take
 place without any obvious functional changes  in the
 biosubstrate. The occurrence of a "biologically im-
 portant" effect depends on the "significance" of the
 substrate in the vital  activities of the cell, or on the
 existence of a reserve metabolic pathway (Dinman,
  The  processes  of  adaptation, and of constant
 restoration (activation  of  detoxication,  intensified
 production of biological structures  bound by the
 toxin, such as enzyme molecules, the inclusion of
 bypasses for normal  metabolism, the activation of
                           the organism's macrosystems aimed at adaptation to
                           new living conditions, and others, for example) are
                           added to this in the integral organism. Thus, damage
                           develops only when the rate at which the damaging
                           processes (inactivation, degeneration, and so forth)
                           occur exceeds the rate at which the  processes of
                           adaptation and restoration occur. These phenomena
                           were well studied during the fractional use of ionizing
                           radiation, and these  are the facts that  became the
                           basis for the ideas as to the threshold  nature of its
                           effect (Strelin, G. S., et al.).
                              Similar phenomena have been described as taking
                           place during the action of chemical factors.  Thus,
                           cessation  of intensified metabolization of bromo-
                           benzene  in p-bromophenylmercapturic  acid (durinv
                           extended  action)  was  accompanied by decompen-
                           sated pathology (T. Shamilov). An increase in the
                           expiration of methylene chloride, and a correspond-
                           ing  reduction in its  content in  the blood, led to
                           physiological adaptation (with a conditionally mono-
                           tonic 1.5-month effect) (G. G. Avilova and N. M.
                              Adaptation at  the  subcellular,  cellular,  organ,
                           organism, and population  level while under the ex-
                           tended effect of  a damaging factor has repeatedly
                           been demonstrated when the external effect has been
                           most varied  in its nature. Included here is the repair
                           of chromosome rearrangements in the case of frac-
                           tional irradiation (N. P. Dubinin, S. P. Frmonenko,





                             YIELD  OF  K  FROM ERYTHROCYTES  (PERCENT)

                              10  20   30 40  50  60  70 80 90  100
           2468      TO      12

              Pb CONTENT IN  SOLUTION   (x10-« Mol/ml)
                              VOL. 276, p. 80 (1958)

                              YIELD OF K FROM THE ERYTHROCYTES AS A
                              FUNCTION OF THE Pb CONTENT  IN SOLUTION

et al.)» the normal life of human populations under
increased  (up to  a predetermined  limit) radiation
background conditions (high mountains, areas in
which radioactive ores are present, and the like),
repair of chromosome rearrangements in the case of
the extended effect of mutagens:  ethylenimine, L. D.
Katosova, 1972; ethylene chlorohydrine, G. K. Isak-
ova, et  al.,  1971; 2-methylthio-4,6-bis-(isopropyla-
mino)-sym-triazine (prometrin), DDT, 2,4D, L. P.
Yefimenko, 1973, v. N. Fomenko, et al., (Figure 2),
rapid inherited adaptation of bacterial to  antibiotics,
of insect populations to insecticides, and so forth.
   The law of natural selection is not applicable to a
human population, so the precise facts as to the true
adaptation of man to life  under  chemical pollution
conditions have not yet been forthcoming.
   The theory of harmfulness of the effect is of great
importance in the problem of the threshold  nature
of an organism's reactions to external effects. What
is important to the protection of the environment is
not any  threshold  of reaction of the biosubstrate, but
the threshold of reactions that have the harmfulness
criterion.  Similar  ideas were formulated  by N. S.
Pravdin in 1934,  and the  theory was developed by
his successors.  More and  more scientists have  re-
cently subscribed to the propositions expressed. Weil
(1972), for example, believes there are  dose levels
that have no harmful effects on any animal species
                                      or on humans, although the effect may be statistically
                                      meaningful. I. G. Akoyev, et al. (1972), while con-
                                      firming the nonthreshold nature of primary reactions
                                      to radiation  effect, advanced the  hypothesis of a
                                      threshold number of damaged  systems; that  is,  the
                                      hypothesis of a threshold of harmful effect.
                                         Thus, the  theory of the threshold nature  of  the
                                      effect does not imply reaction of the biobustrate to
                                      the effect  of  external factors in general, but rather
                                      reactions that are biologically (including medically)

                                      Analysis of Dose-Effect Curves
                                         The threshold nature of the harmful  effect of  ex-
                                      ternal factors can  be demonstrated by an analysis
                                      of the dose-effect curves. Many of the ideas that have
                                      evolved as to the nonthreshold  nature of the effect
                                      have been the result of  assumptions and extrapola-
                                      tions. The dose-effect relationship  is not linear, so
                                      the establishment of the end of the curve  corres-
                                      ponding to the lower level is  extremely  important
                                      (Weil, 1972; Stokinger, 1972; Weisburger, 1968;
                                      Bock,  1968;  Mantee,  et al.,  1961, 1963;  Brues,
                                      1958). The  conditions under which the experiment
                                      is performed (species, sex, age  of  animals, state of
                                      nutrition, and so forth)  have a significant effect on
                                      the shape of  the curve; so the results of determining
                                      thresholds should be reproduced  many times over.

1.5    2.5
mon   mon
          	 1/50 LDso prometrin
          	1/50  LD5Q lindane

.1/50  LD5Q butyl  ether, 2, 4D
.1/50  LD50 DDT
                     BUTYL ETHER, 2, 4D;AND DDT IN THE BONE MARROW
                     OF RATS

 The intensity of the organism's reaction usually de-
 creases with reduction in the dose of the  substance
 administered, with the reaction dropping to zero be-
 fore the dose reaches zero (Hatch, 1973).
   As in the past, most arguments today stem from
 analysis of dose-effect curves obtained as a result
 of  the effect of  mutagens and blastomogens. The
 curve of the blastomogenic effect  of 3,4-benzpyrene
 obtained by N. Ya. Yanysheva (Figure 3) enabled
 the USSR to be the first in the world to establish the
 maximum permissible concentration for  this  toxin
 (L. M. Shabad, I. V. Sanotskiy, et al., 1973). More
 and more researchers now tend to favor  the feasi-
 bility of establishing safe levels  for such substances.
   Figure 4 is the curve obtained in our laboratory by
 L. D. Katosova (1973) for  the cytogenetic effects
 in bone marrow  as a function of the chloroprene
 concentration.  The curve  has the shape of an ex-
 pirant over the concentration segment studied. How-
                           ever, in this, as well as in other, similar investigations,
                           only tht yield of a relative number of aberrant cells
                           in experimental  animals beyond  the limits of the
                           variations in the spontaneous level for the control, as
                           well as for the generally accepted "norm," should be
                           considered as the harmful effect. As is known, Gad-
                           dum (1956) considered the  safe zone to be the
                           magnitude LD00  ±  6er, so that the probability of
                           the onset of a fatal result in this case is 1CH.
                             The threshold of the harmful effect of a substance
                           is that minimum concentration of it in  an environ-
                           mental object, the effect of which will cause changes
                           to occur in the organism (under concrete conditions
                           for the admission  of the substance)  that exceed the
                           limit of physiological adaptive reactions, or latent
                           (temporarily compensated) pathology.
                             The commission designated to  fix the maximum
                           permissible concentrations of harmful substances in
                           the production sphere developed a tentative definition









                                          Experimental curve-
                              Calculated curve*
                                                     ~ -.   .    .
                            .                         Q •>-  tv   o
                         DOSE OF  3, 4-BENZPYRENE  (in mg)
                                                               p  p
                   WHERE Xn  IS THE DOSE (in nig) (REFERENCE  POINT);
                            X IS THE MAXIMUM INEFFECTIVE DOSE IN  THE
                              EXPERIMENT, EQUAL  TO 0.02  mg.

         SOURCE:  YANYEHAVE, N. YA..  GIGIYENA I SANITARIYA, No. 7,  10., 90 (1972)
                       A FUNCTION  OF  THE DOSE OF 3, 4-BENZPYRENE
                       MONGREL RATS.

                               .054 .064  0.3   .32
        1.45  3.5
log concentr.
in mg/m3
                             CELLS OF ANIMALS AS A FUNCTION OF THE
                            CHLOROPRENE CONCENTRATION
of the criteria for the harmfulness of changes result-
ing from the effect of a particular substance that was
based on the departure of an index beyond the limits
of annual or seasonal variations in the norm (± 2ir),
as well as the stability of the  changes, even though
not exceeding the norm.
   However, a  formal approach  such as  this  is not
always satisfactory because in  the  first  place, the
norm is not known in all cases.
   In our opinion, the question of criteria of  harm-
fulness may be resolved by  the delimitation of a
stage of the true physiological  adaptation  to changed
environmental conditions  and  of a stage  of  latent,
temporarily compensated pathology under the effect
of minimally effective quantities  of the toxin.
   We have introduced into the system proposals for
methodological procedures for use in resolving the
problem described  (I. V. Sanotskiy, N.  G. Ivanov,
N. M. Karamzina, V. N. Fomenko, 1971). The pro-
posal was  to  use  the  following  known biological
criteria of the correspondence  of environmental  con-
ditions as the basis:
   • the normal condition for the population (con-
stancy of numbers of the species);
   • the capacity of the organism to adapt  to the
environment (the  law of the unity  of organism and
   • preservation of the organism as a  single bio-
logical system.
  This approach served to establish, in particular,
that the use of functional and extremal loads is a deli-
cate matter, and that their intensity  must be varied
widely. A comprehensive investigation is necessary
to differentiate physiology and pathology in the inte-
gral organism. Thus, adaptation to stimulating toxins
in terms of a  respiration frequency test was ac-
companied  by pronounced pathology  in terms of
morphological criteria  and olfactometry  (V. S. Poz-
dnyakov).  Repairs to chromosome  damage  in the
bone marrow as a  result of the effect of prometrin
were accompanied by the occurrence  of chromosome
rearrangements in the liver tissue (L. P. Yefimenko,
A. Ye. Kulakov, 1969), and so forth.
  Constancy in species numbers within known limits
can be predicted under  laboratory experiment con-
ditions. The system of tests that was devised resulted
in establishing thresholds of harmful  effect for many
toxins  on the processes of reproducing future gen-

  Proof of the threshold nature of  the intensity of
harmful  effect is of enormous importance  for intel-
ligent,  practical activity to protect and  to improve
the sanitary conditions of the environment surround-
ing man at work and at home, and to determine the
permissible load on human populations.
  If a harmful substance  cannot be removed com-
pletely from production, from community and home

 environments, and from the biosphere in general, its
 content in environmental  objects must be subject to
 toxicological limitation based on a  determination of
 the thresholds of harmful effect. If the rate of decay
 and removal of the substance from the environment
 does not exceed the admission rate, the balance must
 be restored, with the thresholds of harmful effect of
 the substance on living systems taken into considera-
 tion. If the substance is concentrated in the environ-
 ment, and this includes the food chains, its emission
 must be  prohibited, particularly by means of closed
 air- and  water-supply cycles.
   The permissible  load  of  a  chemical  factor cor-
 responds to its  maximum permissible concentration
 in  environmental objects. This  we  defined  (I.  V.
 Sanotskiy, 1970)  as the  concentration, the effect of
 which  on the human body periodically, or  through-
 out a lifetime, directly  or indirectly through ecologi-
 cal  systems, as well as  through  possible  economic
 losses, causes neither  somatic nor  psychic diseases
 (including latent and temporarily compensated)  nor
 changes  in the  state of health exceeding the limits
 of  adaptable  physiological reactions detectable  by
 modern research methods immediately or later in the
 life of present and subsequent  generations.
   Known is the fact that  a multifactor analysis with
 broad  formalization of the initial data is needed to
 make a synthetic estimate of the correspondence, or
 noncorrespondence, between a chemical component
 in the environment as a whole and hereditary,  as well
 as  acquired,  properties of living systems. The most
 difficult stage of formalization  in  the case of  socio-
 logical estimates is that  on  questionnaire methods.
 Nevertheless, certain publications  along these lines
 already have been obtained.
   The problem  of  the   distribution  of  individual
 sensitivities,  and of a concrete  population,  causes
 great difficulties.
   Collaboration  between  scientists  with  different
 specialists,  collaboration   between   scientists  from
 different  countries, is the most effective  way to en-
 sure progress in the theory and practice of protect-
 ing the biosphere against  chemical pollution.


 Akoyev, I. G.; Maksimov, G. K.; Malyshev, V M., Luche-
  voye  porazheniye mlekopitayushchikh  i statisticheskoye
  modelirovaniye  [Radiation damage to  mammals  and
  statistical modeling], Moscow, 1972.
Vvedenskiy,  N. Ye.,  Vozbuzhdeniye,  tormozheniye, narkoz
  [Excitation,  inhibition,  narcosis], St.  Petersburg, 1901.
Dubinin, N. P., Problemy  radiatsionnoy genetiki [Problems
  of radiation genetics], Moscow, 1961.
Dubinin, N.  P.;  Tarasov, V. A.,  In coll: Sovremennyye
  problemy  radiatsionnoy  genetiki [Contemporary prob-
  lems of  radiation genetics],  Moscow, 1969, 3.
Yefimenko, L. P.; Kulakov, A. Ye., In coll: Mater, konfer.
  molodykh nauchnykh rabotnikov. Instltut gigiyeny truda
  i profzabolevaniy [Materials of the  conference of young
  scientific workers.  Institute of  Industrial Hygiene  and
  Occupational  Diseases],  1969,  Moscow,  139-140.
Isakova, G. K.; Ekshtat, B. Ya.; Kerkis, Yu. Ya., Gigiyena
  i sanitariya, 1971, No. 11, pp. 9-13.
Katospva,  L. D., "An evaluation of the danger of the muta-
  genic effect of  ethylenimine and chloroprene," Author's
  summary of candidate's dissertation, Moscow, 1973.
Kurlyandskaya, E. B.;  Sanotskiy,  I. V.,  Gigiyena  truda  i
  profzabolevaniya, 1965, 3, pp. 3-9.
Ivanov, N.  G.;  Kudinova,  O.  V.;  Pozdnyakov,  V.  S.;
  Klyachkina, A. M., "Reduction  of the  sense of smell in
  animals  as  an index  of  the harmful effect of industrial
  toxins,"  In coll: Toksikologinovykh  prom.  khim.  v-v.
  [Toxigenic industrial  chemicals], No. 13, Moscow, 1973,
  p. 33.
Pravdin,  N. S., Rukovodstvo promyshlennoy toksikologii
  [Handbook of  industrial toxicology],  Moscow,  1934.
Pravdin, N. S., Metodika maloy toksikologii promyshlennykh
  yadov [The  methodology of minor toxicology of indus-
  trial toxins], Moscow, 1947.
Sanotskiy,  I. V., "The Influence of Different Doses of Radio-
  thorium on Reproduction," Candidate's Dissertation, Mos-
  cow, 1950.
Sanotskiy,  I. V.; Avkhimenko, M. M.; Ivanov, N. G., In
  coll:  Toksikologiya novykh  promyshlennykh  khimiche-
  skikh veshchestv [The toxicology of new industrial chem-
  icals], No. 9, Moscow, 1967, p. 71.
Sanotskiy,  I. V., In book: Melody opredeleniya toksichnosti
  i  opasnosti khimicheskikh veshchestv  [Methods  for de-
  termining the toxicity  and danger of chemicals], Moscow,
Sanotskiy,  I. V.;  Ivanov, N. G.;  Karamzina,  N.  M.; Fo-
  menko,  V. N., In coll: Nauchnyye osnovy sovremennykh
  metodov gigiyenicheskogo normirovaniya  khimicheskikh
  veshchestv v okruzhayushchey srede [The  scientific bases
  of modern methods for fixing hygienic norms for chem-
  icals in  the environment], Moscow, 1971, pp. 63-68.
Simonov, P. y., Tri fazy v reaktsii organizma na vorzrasta-
  yushchiy stimul [Three phases in the reaction of the or-
  ganism to increasing stimulus], Moscow, 1962.
Strelin, G  S.; Med. radiologiya, No.  2, 1960, p. 77.
Fomenko,  V. N.; Strekalova, E.  Ye.;  Katosova.  L. D.;
  Chirkova,  Ye. M.; Sal'nikova, L.  S.;  Silant'yeva, I. V.;
  Yefimenko, L.  G.; Kulakov,  A.  Ye., "Pharmacology.
  Chemptherapeutic  agents. Toxicology,"  Itogl  nauki   i
  tekhniki [Summaries of science and technology], Vol. 5,
  1973, pp. 128-145.
Hatch, T., WHO  Bulletin,  1973, Vol. 47, No. 2, pp. 153-
Shabad, L. M.; Sanotskiy, I. V.; Zayeva, G. N.; Bruyevich,
  T. S.; Katsnel'son,  B. A.; Yanysheva, N. Ya.; Shugayev,
  B. B., Gigiyena i sanitariya, No.  4, 1973, pp. 78-81.
Yanysheva, N. Ya., Gigiyena i sanitariya, No.  7, 1972, pp.
Yarmonenko, S. P.; Palyga,  G. F.,  Med. radiologiya, No. 3,
  1963, p. 66.
Bock F.C. Nat. Cancer Inst. Monogr.,  1968, 28, 57-63.
Brues A.M. Science, 1958, 128,693-699.
Dinman B. Science, 1972, 175, N. 4021.
Gaddum J. H. Brit. J.  of  Pharmac and Chemother, 1956,
  11(2) 156-160.
Grigarzik H., Passow H. Pflugers Archiv.  Bd. 267, S. 73-92
Hatch T.E. Arch. Environ. Health, 1971, 22, 687-689.
Frohbere H., Baner A. Arzneimittel-Forsch, 1973, 23, N. 2,
Mantel N., Heston W. E., Guriam J. J.  Nat. Cancer Inst.
  1961, 27, 203-215.
Mantel N. Clin Pharm. Ther. 1963,  4, 104-109.
Stokinger  H.  E. Arch.  Environ. Health,  1972, 25, N. 3,
Weil C .S. Toxicol and Appl. Phormocol., 1972, 21, N. 4,
Weil C. S. Inf.  Congr.  Pharmacol.  San. Francissa Calif.
  1972, Abstrs. Invit.  Presentat. (1972) 258-259.
Weisbirger J H., Weisburger E. K. Food Cosmet. Toxicol.
  1968, 6, 235-242.

  Questions of Extrapolating Data in Evaluating  the  Mutagenic
                 Action  of Environmental Factors on  Man
                                        N. P. Bochkov *
  Experiments  using  animals  are unavoidable in
evaluating the mutagenic  action  of environmental
factors on man. No one can dispute this rule.  Our
success in gaining knowledge of the genetic danger
to man  from ionizing  radiation,  alkylizing com-
pounds, and other mutagens is associated with large-
scale experimental research on animals.
  In the  1930's, G. Meller, N. V. Timofeyev-Res-
sovskiy, and other geneticists, for the first time posed
the question of the danger of ionizing  radiation to
man's heredity  based  on  extrapolating  results ob-
tained using animals.
  Experimental genetics presently  has a vast arsenal
of methods  for checking  the mutagenic action of
various factors on animals. They include cytogenetic
methods  applied  to somatic  and  embryonic  cells,
consideration of dominant lethals, recessive lethal
mutations and recessive and dominant apparent mu-
tations.  Experiments  have been  performed using
drosophilae, mice, rats, guinea pigs, and rabbits. The
most valid conclusions have been  obtained from ex-
periments using drosophilae and  mice. The  other
animals have been used,  as a rule,  in cytogenetic
experiments,  or in experiments that took dominant
lethals into consideration. Gene mutation considera-
tions in mammals are  very time consuming and ex-
pensive.  Nor does consideration  of the dominant
lethals even begin to settle the question, because this
is a collective  group of  genetic  damages, usually
vague in  nature.
   It is desirable, when considering the  present  state
of the problem of extrapolating  data  obtained on
animals to man, to discuss the following questions.
   1. What  are the circumstances that  force  us to
turn to extrapolation?
   2. What permits us to make extrapolations?
   3. What hinders making extrapolations?
   4. How should extrapolations be made?
1. What are the circumstances that force us to turn
   to extrapolation?
   The enormous importance of direct  data in  eval-
uating the effect of mutagenic factors on man's he-
redity is well known. However, research in the mu-
tagenic effect of environmental factors must be con-
ducted quickly as possible. Consequently, even vast
quantities  of data and  the most  improved methods
for considering gene mutations in human embryonic
cells cannot  accomplish the primary task, that  of
verifying the mutagenicity of environmental factors,
since they require more time, from several years  to
several decades. Therefore,  models must  be used.
These can be human cells in a culturel,  or animals.
   Chromosome aberrations and  aneuploidy  in hu-
man somatic cells can be studied by the effect  of
mutagenic factors on the organism, and on animals
to consider  chromosome and genome mutations  in
somatic cells. Procedures that use human cells are
sufficiently well-developed for this  purpose.  How-
ever,  similar experiments  are  impossible when we
turn to embryonic cells. This raises the question  of
whether it is right to judge  embryonic cells by so-
matic cells?  Obviously not, because the  formation of
embryonic cells includes a  number  of mitotic di-
visions and  meiosis. The nature  of chromosome be-
havior in meiosis  differs sharply from mitosis, which
leads to different quantitative  and  qualitative be-
havior patterns in the mutation process in embryonic
and somatic cells. This raises for the geneticist the
question of  the desirability of testing  mutagenic fac-
tors on animals (so as to take  chromosome  aber-
rations  into consideration)  and extrapolating the
data to man.
   But it is nevertheless sometimes possible, although
difficult, to  obtain human embryonic cells for cyto-
genetic research, and thus estimate chromosome mu-
tation frequency.  It would seem  that  in this case  we
can manage without extrapolations. However,  as an
analysis of the data in the literature  shows, there is
a great  difference in the frequencies  of  gene and
chromosome mutations for  the  effect  of  the same
mutagen. It is  not simply a matter of the different
nature of the qualitative responses,  but rather that
chemical mutagens can induce one type of mutation,
yet have no effect on another.
  •Institute of Medical Genetics, Academy of Medical Sciences of the USSR, Moscow

   Attempting to delineate the question of gene mu-
 tations, we again are faced with the choice of one of
 two approaches; either  induce gene mutations in a
 culture of  human cells (the  procedures have now
 been developed),  or experiment  on  animals. Nu-
 merous data  show the great differences in  mutation
 frequencies in vivo and in  vitro,  and  this  is what
 makes  experiments on  animals, and extrapolation,
 necessary. Whether some  of them are adequate,  or
 not, will be gone into in what  follows.
   Thus, three circumstances force us to turn to ex-
 trapolations; the difference in the mutagenic response
 of somatic  and embryonic cells, the difference in the
 frequency of induced, gene, and chromosome mu-
 tations, and the difference in the frequencies of mu-
 tations  in vivo and in vitro.

 2. What permits us to make extrapolations?
   Many of the conditions that force us to turn  to
 extrapolations in evaluating mutagenic factors in the
 environment  were enumerated above.  But  at  the
 same time,  all are, as it  were, contraindications. Can
 we make extrapolations anyway, or  is doing so  a
 useless  task?  What is it that  permits us to answer
 the question of the correctness of making extrapola-
 tions in the affirmative?
   The structure of the individual chromosomes, and
 of the karyotype, in higher  animals conforms to  a
 single principle. The chromosome is a strictly ordered
 nucleoproteinic structure, which undergoes  identical
 changes in the process of reproduction and function-
 ing.  With  the single  principle of  the chromosome
 structure as a basis, it can  be assumed that there are
 common behavior patterns in chromosome reactions
 to mutagenic effects  when the mutagens reach the
 chromosomes. Experimental  data confirm these  as-
 sumptions. Based on a great deal of research in the
 mutation  process, we  can  speak of its  universality.
 We can see by the example of radiation and of alky-
 lizing agents that the similarities in the mutagenic
 responses of the higher  organisms  are greater than
 the differences, especially  as regards the qualitative
 response.  All  substances that have been found to be
 mutagenic  for mammals cause chromosome  abera-
 tions  in human somatic cells  in  vitro  and,  where
 tested, in  vivo as well.

 3. What hinders making extrapolations?
   The problem  of extrapolation would not arise if
 there were no differences in the mutation response of
 the various organisms. The  data  obtained  for any
 organism simply would be used to evaluate the hu-
 man mutagenic danger. However, this is not so, and
 the more the  mutation process is studied, the  more
the restrictions placed on extrapolation.
   The first  major restriction  on extrapolation is as-
sociated with  the difference in the  metabolism of
 chemical substances in animals and man. Let us, by
 way of an example, cite thalidomide, the embryotoxic
 effect of which is strongly manifested in man,  but
 not at all in rats. Many chemical compounds  are
 toxic for one species, yet decompose  rapidly in  an-
 other. This most  often is  associated with hereditary
 features of  metabolism.
   What follows from  the extrapolation  restrictions
 considered above  is that  the metabolism of the mu-
 tagen in man and in  animals must be known if cor-
 rect extrapolations are to be  made. Obviously,  ex-
 trapolations  will  be  more  accurate  for radiation
 mutagenesis  than  for chemical.
   The second restriction placed on extrapolation is
 associated with the  dissimilar qualitative  behavior
 patterns in the mutation process in different animals.
   Moreover, it  is  apparent that induced mutagenesis
 can be stronger or weaker in man. There is no basis
 for assuming that  it always is more intensive in man
 than  in animals.
   What causes  the quantitative differences in the in-
 duced mutation process in different animals? Induced
 mutagenesis,  as has  been established recently  by
 different authors,  is an unusually  complex process,
 one that can be influenced by many factors. The pri-
 mary damage from mutagens, apparently, is of a  po-
 tential nature. The cells contain reparative systems.
 All of this leads to  quantitative  variations  in  the
 mutation process.  Reliable procedures for evaluating
 the role of the  primary and secondary processes in
 the differences  in the mutation response remain to
 be developed. The importance of  the phase  of  the
 cess cycle for mutation frequency, the importance of
 type  of cells,  of the species and age of the animals,
 has  been  discovered  for radiation and chemical
 mutagenesis. The  relationship between mutation fre-
 quency and mutagen dose can be different in different
 animals, and  this fact makes  extrapolation partic-
 ularly difficult.
   We can cite several papers to illustrate these prop-
 ositions. N.  I. Shapiro and Yu. Ya. Kerkis were  the
 first to establish the fact of dissimilar radiosensitivity
 of the chromosomes of different species of animals.
   Dominant  lethals were taken into consideration in
 the experiments conducted by  N.  I. Shapiro. It was
 found that the numerical incidence of lethals in mice,
 rats,  and rabbits,  was dissimilar, with  the  rabbit
 showing a  higher death rate of zygotes before
   More  comprehensive  work  was  conducted  by
 M. Lyon and B. Smith, who evaluated the frequen-
 cies of dominant  lethals  at different times  after  ir-
 radiation. They established the fact that it is not
just a matter of  the differences  in the general genetic
radiosensitivity, but also that the radiosensitivity will
vary differently in  different animals, and at different

  The dissimilar frequency of dominant lethals in
different  animals and their  dissimilar  shift during
spermatogenesis have  been noted  in  the effect of
ionizing radiation, as well as of chemical mutagens.
This can be seen in the data provided by M. Lyon,
B. Smith, and D. Bateman. It is important  to note
that the  curves are dissimilar,  and that the mean
frequencies differ.
  The differences in the frequency of induced aber-
rations in different  organs and in different  types of
cells in different animals can be  seen  in the work
done by Yu. Ya. Kerkis, et al.
  The extrapolation problem is complicated by the
fact that there are age differences in the response to
mutagenic  actions.  This  has been  described by  a
number of authors for animals, and we  have  done
so for man.
  The following rule  has thus far been  applied to
extrapolations:  gene mutations increase linearly with
the dose, and chromosome mutations as the square,
with the genome mutations question unresolved.
  These conclusions  have not always been  reached
on  the basis of strict statistical criteria. For example,
it is now well-established that the dependence on the
dose is not the  square and determinate for radiation-
induced aberrations.
  The sum of the experimental data permits the con-
clusion to be drawn that the coefficients of the equa-
tions of  mutation frequency in different species of
animals (or types of cells) are different, and depend
on  the mutagenic factor dose. All this speaks to the
enormous  difficulties  standing  along the  road of
extrapolations.  Things are even further complicated
by  the fact that the yield of muttaions per dose unit
differs for different dose ranges. And  as  a  rule, the
experimenter is not  working with the  same doses
with which man comes in contact.

4.  How should extrapolations be made?
  The question of  the  mutagenicity of  any factor
for man is decided primarily on a qualitative basis.
Extrapolations  therefore, are of  the  same nature.
What rules can we propose on the basis of the sum
of contemporary knowledge?
   (a) First of all,  the researcher  is confronted  with
a dilemma; should  the extrapolations be made from
human cells in  a culture, or from animals? The eval-
uation of the mutation process  is a  very  complex
procedure. After all, three types of mutations (gene,
chromosome, and  genome)  must be taken into  con-
sideration, as must  at least  two types  of cells  (so-
matic  and embryonic),  and the metabolism of the
chemical mutagen.  There is, therefore,  no unambig-
uous answer to this  question in all cases.  The de-
cision  is different  in  each concrete case. Preference
sometimes may be given to a culture of human cells,
sometimes to animals.
   (b) If mutagenicity of any factor is detected for
an  animal, it must be considered mutagenic  for man,
with the exception perhaps of those cases when the
metabolism  of  the mutagen in animal  and in man
differs sharply  at precisely the point of application
of the mutagenic activity. Failure to observe a muta-
genic effect of a compound in one, or even in several
species, does not mean that it is safe for man, but
only that we may hope it is.  This approach seems
objective to us, because of the great importance of
underestimating the  presence  of a mutagenic effect
attributable  to any  chemical  substance (more im-
portant than  overestimating). Thus,   a  mutagenic
effect established for any  animal object must be di-
rectly extrapolated  to  man, although this may not
always be confirmed. Negative results in investigating
a  mutagenic effect  must  be  extrapolated with ex-
treme care in the sense of the absence of a mutagenic
effect by a  certain chemical  substance  on man's
heredity, and only for  the condition that the metab-
olism of the compound in the research animal and
in man is exactly alike.
   (c) If the mutagenic effect  of any factor is estab-
lished for animals, the  task of  quantitative extrapola-
tion arises, because the basic approach  to evaluating
environmental  factors   must be the population ap-
proach. If numerical data are obtained for several
species  of animals, it is better  to proceed using mean
data, rather than using data on one species of ani-
mals, when  evaluating  the mutagenic danger to man.
Of course, the task  of  extrapolation will be difficult
if drosophilae  and mice are included in this group.
Preference usually should be given to mammals, par-
ticularly in the case  of chemical mutagenesis. Quan-
titative conclusions  cannot be precise, even  when
all extrapolation  requirements are met  as strictly  as
indicated. The estimates will be approximate in any
case. Therefore one must  strive  to determine  the
order of the danger, not the precise figures. Thus,
quantitative  extrapolations  should  be  made  more
carefully than  qualitative  ones.
   In the case of quantitative extrapolations,  it is
important to evaluate  the total mutagenic response,
proceeding from the different sensitivity  of the phases
of the  cell  cycle, according to the weighted  mean
   (d) The geneticist is confronted with two complex
questions when  evaluating the  mutagenicity of  a
factor;  what animals to use in the experiments, and
which tests  to  select for the genetic evaluation. Ob-
viously, the two  main species of  genetically well
studied and convenient objects should be mentioned
first, drosophilae  and  mice.  A  great  many muta-
tions can be  studied  in each of  these species,  but
expanded  experiments on  mice  to take  recessive
mutations into consideration  are very  time-consum-
ing  and expensive.  The drosophila therefore is most
often  used.  Experiments with mice as a  rule  are
limited to dominant lethals.  Experiments must use
mammals when  a  widely distributed  substance,  or
factor,  is being checked,  or when there are reasons

 for an  assumption as to its  mutagenic effect. When
 the mutagen does not penetrate the testicles in ani-
 mals, but does so in man, experiments can be set up
 so that the mutagen  is injected into the  scrotum  of
 the animals.
   (e) It is not always necessary to attempt to make
 extrapolations. If experiments  can be  set  so that
 human cells are  used, it  becomes  mandatory that
 extrapolations  not be made. There are no adequate
 models for evaluating chemical  mutagenesis in man.
 Therefore, the  current problem, and one that applies
 in all cases, is that of obtaining direct data on the
 influence of mutagenic factors on man's heredity. It
 is necessary, for  example,  to extrapolate the cyto-
 genetic effects  in  somatic cells. Modern  procedures
 permit doing this directly on human cells as  a  result
 of the effects of the  mutagenic factors in vivo and
in vitro.  The large-scale development of procedures
for taking gene mutations in human  somatic cells
into consideration will narrow  the  circle of ques-
tions  for  which it will be necessary to extrapolate
data.  At  the same time, and in conclusion, it should
be  emphasized that  as our knowledge of the mu-
tation process increases, the limits of the potentials
of extrapolations will become clearer, and the selec-
tion of the  models used to evaluate environmental
mutagenic factors will be more objective.
  Extrapolation,  in  the final  analysis,  is based  on
the results of experimental modeling. Consequently,
the better the  experimental object  is selected, the
more  accurate will be the extrapolation. Well known
from  experimental pathology  is  how  attentive  and
careful one must be  when  modeling any  of the
human pathological processes.

        The Question of Genetic Danger from  Environmental
                                        L. M. Filippova *
  Pollution  of the habitat of living  organisms by
biologically  active  agents—chemical  (the  wastes
from different industries, erosion  loss from agricul-
tural areas,  and the like), as well as physical  (in-
crease  in the radiation  background, thermal  pol-
lution,  noise,  and others)—has  become a  side-
effect of the development of the human society.
  The  progressing pollution of the natural environ-
ment has a number of biological consequences, with
one of the principal ones the danger of  the occur-
rence in the majority of cases of negative hereditary
changes in man,  as well as in animals and plants,
under the effect of chemical  and  physical agents in
the  environment. The great  many chemical com-
pounds  entering  the natural environment, individ-
ually and in a variety of  compounds, are capable
of inducing  gene, genomic, and chromosome muta-
tions, which cause  an increase in the frequency of
congenital deformities, defects and anomalies, many
hereditary  diseases, stillbirths,  spantaneous abor-
tions, and the like.
  Major chromosome damage (aberrations) causes
a genetic defect the scale of  which is such that the
damage is rarely  transmitted by heredity  because of
the  poor viability, or sterility, of the carriers,  and
this is  precisely why aberrations  have little impor-
tance from the standpoint of  population.
  Recessive gene mutations play a special role from
the  standpoint of population. They are harmful to
the  organism in the majority of cases. Transmitted
and  accumulated from generation to generation in
the  latent  (hetero2ygous)  state,  they increase the
"genetic load" of the population. The problem of the
"genetic  load" is a particularly  serious  one for a
population in  which the effect of natural selection
has weakened, and this would apply  to the human
  Systematic study of the  genetic danger of agents
that pollute the environment, of products of chemical
synthesis widely  used in industry, agriculture,  and
daily life [1], has  shown that many of them definitely
have mutagenic activity and can damage the genetic
material  of  living organisms. Mutagenically active

  •Main Administration of the Hydrometeorological Service, Moscow
compounds  have been found  in medicinal  com-
pounds, pesticides, dyes, and others.
  Therefore, no one today can have any doubt about
the fact that all chemical agents that in some way or
another come in contact, in particular, with man, as
well  as with animals and  plants, should  be subject
to genetic control. The  results of such control should
be taken into consideration in setting hygienic stan-
dards,  and  should  further serve  as the  basis for
drastically limiting  the content  of mutagenic sub-
stances in the environment.  The lexicological stan-
dards accepted at the present time certainly cannot
be recognized  as adequate in all cases. While there
are many cases when  the mutagenicity of a  com-
pound  correlates with toxicity, slightly toxic chemical
products often have  mutagenicity. And  it is this
mutagenicity, and not the toxicity, that should be the
limiting factor when setting standards for a chemical
compound such as this.  Paraquinone dioxime, for
example, is  widely used in the  tire and  rubber in-
dustry  and while it has no pronounced toxicity (an
organoleptic index, color, is  used in its standardiza-
tion)  it does  induce  lethal  gene mutations  and
morphoses in Drosophila and chromosome rearrange-
ments  in a  culture of peripheral blood  leukocytes
and in  a culture of human embryonic fibroblasts [2].
Moreover, the mutagenic concentration of triethylene
melamine is less than  the toxic  by a factor of 100
  The evaluation of the genetic threat of environ-
mental  pollutants must proceed from the fact that
in the  majority of cases the  organism will be sub-
jected  to the effects of a large number of mutagenic
agents  in small concentrations. There are, therefore,
two  problems  of primary importance:
     1. the problem of the simultaneous,  or sequen-
tial,  effect of several mutagenic agents;
     2. the problem of defining the threshold of the
mutation process.
  1. The living organism  is subjected to the action
of a complex set  of  chemical  and physical  agents
that  penetrate the organism over different  paths and
from different media.

   Recent papers have dealt with the mutagenic effect
 of two chemical  agents, two physical (irradiation  +
 temperature,  for example)  agents,  or  a chemical
 agent in combination with a physical agent (chemical
 mutagen +  temperature,  chemical mutagen  +  ir-
 radiation, and so on), making it possible to estimate
 the  situation, albeit  tentatively, in  connection with
 the  simultaneous presence in the  environment  of
 many mutagenic  agents. The possibility of additivity,
 as well as of synergism of the genetic effect of two
 mutagenic factors, not necessarily  highly active indi-
 vidually, has been pointed out. This increase  in the
 level of  mutagenesis also  has been observed for
 chromosome aberrations,  as well as for  gene  muta-
 tions [4, 5, 6].  It appears that the reasons for the
 intensification of the effect of combined mutagenic
 effect can be very different indeed. For example, the
 effect of one of the agents can be to change the phy-
 siological state of the cell, change the hereditary ma-
 terial to  the  labile  state,  damage the cell control
 mechanism, inhibit reparative processes,  and so on,
 with the result a reduction in  the  resistance of the
 organism to the effects of the second agent. Nor can
 we exclude the possibility of the appearance of a new,
 more highly mutagenic substance  when  two com-
 pounds interact with each other, and with cell meta-
   2. This gives rise  to a question.  Will the effects
 thus far discussed be valid for the case of extremely
 low  concentrations of mutagenic substances in the
 natural  environment? In  other words,  is  there  a
 threshold of mutagenic effect of chemical agents and
 radiation?  It obviously is impossible to  answer the
 question categorically. And  not only because  our
 present knowledge  of the  question  is limited. This
 also  is so because the genetic effect includes a com-
 plex set of damages to the hereditary material, each
 different from the other, and characterized by  speci-
 fic mechanisms and kinetics.
   Shortwave radiation, and chemical substances to
 an even greater degree, are capable of inducing point
 mutations and simple, primary chromosome breaks;
 that  is,  those changes in the hereditary material the
 basis of which is an elementary chemical act, or  a
 single ionization. Analysis of the  kinetics of these
 "single-strike" mutation events attests to the  linear
 nature of the dose-effect ratio [7, 8]. The dose-effect
 line  can be  extrapolated through  the zero point,
 pointing to the absence of a dose threshold. Actually,
 the formation of a single pair of ions, or the appear-
 ance of a single  molecule  of a chemical mutagen in
 a cell, is perhaps sufficient to induce point mutation
 as a result of just one DNA base change. The  oc-
 currence of mutations in  living organisms is  prob-
 abilistic in nature. Even the tiniest doses of mutagens
can  induce  mutation changes  (which can be  ex-
 tremely  serious,  right up  to being  lethal, caused
by a  single mutation in one of millions  of genes),
 simply among fewer persons.  So,  naturally  enough,
 the probability of genetic damage will decrease with
 decrease in the mutagen dose. The proposition that
 there is no dose threshold for inducing "single-strike"
 mutation events is now well confirmed by direct ex-
 periments [9-13],  Those rare  cases of induction of
 mutations  attributable to the  inhibition of certain
 enzymes  needed for  the production  of  DNA pre-
 cursors are the exceptions. If such an enzyme in the
 norm does not limit the DNA or chromosome repli-
 cation rate, the inhibitor will be  effective  if some
 minimum magnitude is exceeded [14].
   But things are different in  such damage to chro-
 mosome  material  as  complex rearrangements,  for
 which two, or more, independent chromosome breaks
 are necessary.  Here the dose-effect  curve differs from
 that described  above. These structural changes, upon
 irradiation, can be caused by  accumulations of ions
 from  different  tracks that occur independently.  Their
 frequency increase is not directly proportional to the
 dose,  but rather is  more rapid, and there is a thresh-
 old dose [7].  The same thing is seen for the dose
 ratio  in  the case  of  the "double-strike"  ("multi-
 strike") effect  of chemical agents, the result of which
 is the appearance  of  two (of several) independent
 breaks with subsequent regeneration and recombina-
 tion of the chromosome material and the appearance
 of complex  rearrangements of the chromosomes.
   Accordingly, the kinetics of "single-strike" muta-
 tion events (the occurrence of  gene mutations and of
 simple chromosome breaks)  can be characterized by
 the  linear dose-effect ratio and absence of a thresh-
 old. The  frequency  of the "multistrike" mutation
 processes  (the occurrence of  complex chromosome
 rearrangements) increases  more  rapidly than  the
 dose,  and  has a threshold.
   The experimental curve for the induction of muta-
 tions  attributable  to  physical,  as well as chemical,
 agents usually has the following, typical, shape.

                MUTAGEN DOSE


The linear segment, ab, corresponds to the preferred
induction of gene mutations under the influence of
low mutagen doses. The be segment  rebects the in-
crease in the percentage of large, complex, chromo-
some  rearrangements and the decrease of induction of
gene  mutations when  the  mutagen  doses  are  in-
creased [15]. The linear segment, ab, usually is very
much longer for a chemically induced mutation pro-
cess than is the case for shortwave radiation. Many
highly specific, active mutagens (nitroso- and diazo
compounds,  for  example)  induce gene  mutations
with much greater frequency than chromosome aber-
rations. Virtually almost all the chemical mutagens
induce mainly gene mutations in the low dose range.
It is  obvious  that the  mutagenesis  curve will, in
practice, undergo substantial modification from com-
pound to compound because of the  high degree of
specificity of the chemical mutagenesis (discussion of
the nature and causes  of which are pointless in this
report). Nevertheless,  the  tendencies described will
be at the bottom of the mutation process.
  Some researchers  assume they have every reason
to talk  about a threshold for toxic or teratogenic ef-
fects, as well as for mutagenic  (including the induc-
tion of gene mutations). Well known is the fact that
mutation frequency is largely dependent  on the phy-
siological state of the cell at the time of the action,
the special  features  of the cell's  metabolism,  on  a
great many  intra- and extra-cellular factors. Small
quantities of a potentially mutagenic agent that enter
the organism  can  be  completely inactivated,  and
rendered harmless, by the cell's defense mechanisms,
while induced pre-mutation changes can be healed
by  the reparative systems. These  small concentra-
tions  of the  mutagen thus will, for all practical  pur-
poses, be inactive. It would seem  that in cases  such
as these there is an obvious mutagen effect threshold.
But can we, at this point, say that mutagenesis has  a
threshold, in the strict  sense of the word?
   First of all, the magnitude of this "threshold"  is
not absolute for the same compound, and will  vary
greatly not only from object to object, but even from
gene  to gene in the same  genotype. Consequently,
this so-called "inactive" concentration will, to a very
large extent, characterize the degree  of resistance of
the organism to the particular mutagenic action, and
not the threshold of mutagen action. This resistance
on the part  of the organism is a factor that is subject
to changes as it is affected by definite conditions.
   Important, and convincing experimental data [16]
attest to the fact that agents that are  cell metabolism
modifiers cause  significant changes  to  the induced
mutagenesis picture.  Under real,  natural conditions
the actions  of a great  many different chemical  and
physical agents  "subthreshold" under other condi-
tions and concentration, and can have a definite mu-
tagenic effect. Hydrogen peroxide, for example, will
not induce  mutations  in many organisms,  even  in
high concentrations, because  it  is decomposed  by
their catalase.  But if  a toxin that  blocks catalase
(potassium cyanide, or sodium azide,  for  example)
is  added the mutation frequency  will increase, even
when the smallest quantities of peroxide are involved.
   Well known is  the  fact that  an  increase in the
quantity of  oxygen,  carbon  monoxide,  hydration,
visible  light,  temperature,  and other environmental
factors, can sharply increase the frequency of muta-
tions induced by chemical  mutagens and by irradia-
   There can be a sharp increase in mutagenicity as
a  substance  metabilizes  in the environment. Trans-
formation of a substance upon entering the environ-
ment can, for example, lead to a greater capacity to
be adsorbed, or to penetrate, the cell,  such as is the
case with inorganic mercury, which is transformed by
microorganisms into methylated mercury  [17].
   Finally,  the transformation of a "prethreshold"
into a  "postthreshold"  dose can take place  as a result
of the additive, and even  more  so  of the synergid,
effect of two, and  more, mutagenic agents, which we
discussed above.
   So,  two things evidently can happen as a result of
the action by small doses of mutagens.
   1. The organism responds to the effect of  even
the smallest doses of a mutagen by straining the pro-
tective  systems. This  leads  to inactivation,  to the
rapid  elimination  of  the mutagen molecules,  or to
repairation  of the primary  damage to the genetic
material. Mutation will not occur in this case because
the processes involved in the  mutagen action and in
those  opposing such  action are in equilibrium. The
action of the mutagen and, correspondingly, the or-
ganism's reaction  are nonthreshold.
   2.   The strain of the  protective systems reaches  a
maximum with increase in the genetic load. Beyond
this point  the action  of even the smallest dose of
mutagen (and not necessarily the  same  one) will
lead to the formation of a mutation.  Thus, the oc-
currence of  a  pronounced (pathological)  change in
the hereditary structures has a threshold in  the major-
ity of  cases.
   What follows  from the above, then,  is that it  is
of primary  importance when  standardizing the total
genetic load of harmful substances in the environ-
ment to proceed from the  nonthreshold nature of the
effect  of mutagenic agents, and not from the  thresh-
old nature of the  occurrence of a pronounced (path-
ological) character. Even  small quantities of  a  great
number of  chemical  and  physical agents  in the en-
vironment are constituents in the total genetic load
on the living organism. There can be little  doubt that
 if the systems for intracell regulation and the  cell's
reparative  systems protect the  organism  from the
 harmful effect of  a small dose of a mutagen, the cell
 will be in no condition to withstand the simultaneous
 action of tens, or of hundreds, of small quantities  of

 mutagens that would not be fatal to the organism in-
 dividually. And this  is understandable, because ab-
 sence of effect from  low  doses of a mutagen is not
 because the low doses have no effect in the organism,
 it is  the  result of the active counteraction launched
 by the organism's protective systems, the capabilities
 of which, naturally, are quantitatively limited.
mutagenic agents. The only real way  to control the
content of these compounds is  to standardize these
products  at  the emission  source,  or even sooner,
while they are being manufactured.

   Today, we are faced with the urgent need to  ex-
 pose the level of genetic damage attributable to  en-
 vironmental pollution.  Hence,  the task  of  genetic
 monitoring of the human population is an extremely
 important one. All  cases  of  spontaneous abortion,
 anomalies of genetic etiology in the newborn, as well
 as in  older  groups,  and among those  exposed con-
 stantly,  or periodically, to the  effects  of  some par-
 ticular agent (at work, or while  undergoing treat-
 ment, for example), must be  systematically taken
 into consideration and studied, in order  to assess
 changes in the  frequency of gene  and chromosome
 mutations in germ and somatic cells.
   We must introduce genetic methods in standard
 toxicological research in standardizing chemical prod-
 ucts, and  this in  the immediate  future. This task is
 well  within the  realm of  possibility. A  series of
 genetic studies  can be made using the same animal
 that takes part  in an acute, or a chronic,  toxilogical
 experiment (dominant lethal mutations, chromosome
 aberrations in sexual, or somatic, cells, and others).
 Forms of genetic activity  not  accessible  for direct
 analysis in mammals should be tested along  parallel
 lines on adequate models. The determination of per-
 missible quantities of chemical compounds in the  en-
 vironment  should proceed from  the  nonthreshold
 kinetics  of the mutation process, and, as a minimum
 from the summation of the genetic  effect of even  the
 smallest doses of mutagens. The permissible concen-
 trations should be infinitely small in the case of active
 1.  Rapoport, I. A., Filippova, L. M. ZhVKhO im. Mende-
    leyeva, 1970, 6, 681.
 2.  Revazova, Yu. A. "The  Hygienic Importance of Re-
    search in  the Genetic  Activity  of  Industrial  Com-
    pounds."  Author's Dissertation,  Moscow, 1967.
 3.  Matter, B.  E., Generoso, W.  M. Abstracts.  2d Annual
    Meeting of the European Environmental Mutagen So-
    ciety, Czechoslovakia, 1972, p. 40.
 4.  Oster,  I.  I. In: Advances in Radiobiology,  Oliver and
    Boyd (Eds.). Edinburgh, 1957, p. 475.
 5.  Kaufmann, B., Gay, H., Rotnberg, H.  Exptl.  ZooL,
    1949, 111, 415.
 6.  Nikiforov, V. G. V  kn.  Obshchaya genetika  [General
    Genetics]. "Nauka"  Publishing House, Moscow,  1965,
    p. 166.
 7.  Gershkovich, I. Genetika  [Genetics]. "Nauka" Publish-
    ing House, Moscow, 1968, p. 201.
 8.  Rapoport, I. A. V sb. Supermutageny [In  collection:
    Supermutagens]. "Nauka" Publishing  House,  Moscow,
    1966, p. 9.
 9.  Sparrow,  A. H., Underbrink,  A. G., Rossi,  H. H. Sci-
    ence, 1972, 176, 916.
10.  Smith, G. V sb. Genetika raka  [In collection: Cancer
    Genetics], Foreign Literature Publishing  House,  Mos-
    cow, 1961, p. 442.
11.  Freese, E., Freese, B.  Radiat.  Res.,  SuppL,  1966, 6,
12.  Glembotskiy, Ya. L., et al. V sb. Radiatsionnaya gene-
    tika  [In  collection:  Radiation Genetics]. Academy of'
    Sciences of the USSR Publishing House, Moscow,  1962,
    p. 300.
13.  Marcovich, H. These des Sci., 3846, 1957.
14.  Freese, E. In:  The  Evaluation of Chemical Muta-
    genicity Data in Relation to Population Risk.  Proceed-
    ings of the Workshop held at Research Triangle Park,
    N.C. 1973, 171.
15.  Rapoport, I.  A.  Khimicheskiv  mutagenei  [Chemical
    Mutagenesis]. "Znaniye"  Publishing House,  Moscow.
    1966, p. 24.
16.  "Evaluation of Genetic Risks of Environmental Chem-
    icals."  Report of  a Symposium  held at  Skokloster,
    Sweden, 1972, p. 13.
17.  Miller, M. W.,  Berg, G. G., Eds. Chemical Fallout.
    C. C. Thomas, Springfield, Illinois, 1969. 531 pp.

             Hygienic Bases for  Protecting the Environment
        C. I. Sidorenko,* Ye. I. Korenevskaya,* M. A. Pinigin,** G. N. Krasovskiy ***
  The problem  of  protecting the environment has
taken on special urgency in recent years because of
the scientific and technical revolution taking place in
the world.
  Among the many  ecological, technological,  and
biological aspects of this problem in need of study
and urgent decisions, the most important task is that
of  protecting human life,  activities,  and health
(taking the interests of future generations into con-
sideration). The hygienic aspects of the problem of
protecting the environment therefore now are of para-
mount importance.  Here at  home the principle of
priority in protecting health, and the  preservation of
favorable hygienic living conditions for  the popula-
tion, was clearly expressed in a number of resolutions
by  the Central Committee  of the Communist Party
of the Soviet  Union, the Supreme Soviet, and the
Council of Ministers of the USSR on improving pro-
tection of the environment and  on the rational use
of natural resources.
  Wide-ranging  governmental measures  aimed  at
preventing pollution and sanitation of the environ-
ment in the interests of the population are based on
hygienic norms that set a maximum permissible con-
tent of harmful substances in water, atmospheric air,
and food products. A hygienic norm, or  the maxi-
mum permissible concentration (MFC), is that con-
centration of  a  chemical substance  the observance
of  which results in  no  unfavorable  effect  on the
health, well-being, or working capacity of the popula-
tion,  and of  future  generations,  as  detectable by
modern  research methods, while at  the same time
causing no deterioration  in the population's hygienic
living conditions.
   The  development  of  the  principles,  and of the
methodology,  for establishing the MFC is a major
achievement of Soviet hygiene, the more so because
Soviet scientists  (N. V.  Lazarev, A.  N.  Sysin,  S. N.
Cherkinskiy,  and V.  A.  Ryazanov) made the basic
contribution  to  the  development of this scientific
trend. The State Sanitation Code of the USSR, which
is designed to protect man's  environment, now in-
cludes over 420 norms for atmospheric pollution that
involve the isolated and combined effects of  these
  •*'Senior Scientist
  Setting a hygienic norm for chemical factors in the
environment is based on two main principles. One is
the  concept of the presence of  biological thresholds
in the  effect  of these factors. The other is the
principle of a limiting harmfulness  criterion. Thus,
when the MFC of chemical substances in the waters
of reservoirs is scientifically substantiated,  complex
experimental research is  conducted, resulting in the
establishment of  (a) the threshold concentration  in
terms of influence on the organoleptic characteristics
of the water  (odor, taste, color, turbidity), (b) the
threshold concentration in terms of the influence on
the overall sanitary regime in the reservoir (for which
only initial changes in the biochemical processes  of
the  mineralization of organic substances in reservoirs
are detected), (c) the ineffective (subthreshold) con-
centration,  which has no unfavorable toxic  effect on
the human  body.
  The concrete  value  of the MFC is established  in
terms of the most sensitive index  (the  harmfulness
criterion), characterized by the  least magnitude.
  The USSR has established two norms for atmos-
pheric pollution; the maximum  single, and the mean
daily, MFC. The maximum single MFC has  been
established to prevent reflex reactions in man during
short-term  effects of atmospheric pollution, while the
mean daily MFC has been established to prevent its
resorptive effect.
  Experimental research is the basis for setting hy-
gienic norms in  the field of general and municipal
hygiene. The importance of experiments  stems:
  first,  from the interests of preventive sanitary in-
spection, a procedure  that can implement  measures
against  chemical  pollution of the environment during
the  planning stage for new enterprises  and  plants,
and thereby prevent the unfavorable effect of such
pollution on the population;
   second,  from  the possibility under experimental
conditions  of revealing relatively accurately the re-
lationship between each biological effect and the level
of concentration of the  chemical substances,  some-
thing that  is difficult to do under natural conditions
because of the additional effects of  all  the different
factors  present in man's habitat.

   Experimental  research in establishing safe levels
 of chemical pollution for man is proceeding in two
    (a)  an  experiment, using  volunteers,  to reveal
 threshold and  subthreshold concentrations by reflex
 reactions during  brief periods of  inhalation of a sub-
 stance  in terms of its influence  on the  organoleptic
 characteristics  of water that  is  completely safe for
 the subjects;
    (b)  a lengthy, continuous experiment on animals
 to establish threshold  and subthreshold concentra-
 tions in terms of a toxicological criterion of harm-
 fulness of the substance.
   The  first stage  in the  development  of  hygienic
 normalization in the USSR (the 50s through the 70s)
 has been characterized by the  accumulation of  a
 great deal  of  factual data to justify the MFC for
 those chemical factors which are most often the cause
 of environmental pollution. Theoretical generaliza-
 tions of the accumulated data have begun to be made
 in recent years because of the  need to carry out the
 important task of increasing  the  reliability  of  the
 MFC that have  been established by perfecting  the
 methodological  and  theoretical  bases  for  hygienic
   The  problem of the combined  and complex effect
 of substances is  deserving of  special attention. We
 know  that  mixtures (combinations)  of substances
 can cause different effects, synergism, antagonism, an
 independent effect, depending on the nature of their
 toxic effect  and on content level. The experimental
 research that has  been conducted  to estimate  the
 nature of the combined effect of substances polluting
 the air, as well as the reservoirs,  has shown that an
 additive effect occurred in many cases. However, this
 question still is far from resolved because of the ex-
 treme complexity of the composition of pollutants,
 and the relatively low  level of their content  in  the
   This  means  that we must make further improve-
 ment in the methods used to study the combined ef-
 fect when concentrations of substances are at low
 levels, as well as to study the principles for estimating
 the nature of the summed biological effect  of com-
 plex mixtures. Experimental research is now in pro-
 gress along  just such lines in institutes in the USSR.
   Even more complicated is estimating the danger of
 the complex effect  of a substance entering the body
 simultaneously over  different pathways  (from  dif-
ferent media). The current practice of  establishing
hygienic norms for the same chemical substances
 separately for atmospheric air, the air in production
areas, for water in  reservoirs,  and for food products
fails to  consider the possibility of their entering the
body simultaneously over  different pathways. This
gives rise to the need to develop  methodological ap-
proaches to  complex  (unified) hygienic normaliza-
tion for chemical compounds in the environment.
   In view  of the difference in the principles and
 criteria for establishing maximum permissible  con-
 centrations of harmful substances for different media,
 what we are talking about at this stage is the develop-
 ment of approaches to unified hygienic normalization
 for substances, the permissible content  of which can
 be limited by their resorptive, that is, their toxic,
   The integration of hygienic normalization, or uni-
 fied  hygienic  normalization, in  different  environ-
 mental  objects, while  an urgent requirement of the
 times, is an extremely complex problem, the solution
 of which certainly will not be  a unique one in all
   We know that  a  different content often finds its
 way into  the very concept of "unified hygienic  nor-
   It is not our purpose to provide a precise and uni-
 versal formulation of this concept. We will  simply
 point out that at  this time  we  are not including hi
 this concept the task of establishing a  unified MFC
 magnitude for all media. The problem of integration
 of hygienic normalization is associated  specifically
 with answers to the following questions:
   1.  The development of principles and methods for
 estimating the danger  and  safety of  harmful  sub-
 stances upon their complex admission to the body, as
 well as unified approaches  to estimating the simul-
 taneous pollution of different environmental  objects.
   2.  The development  of  unified  criteria  for the
 harmfulness and harmlessness  of a chemical factor
 for the body, and scientific justification for  unified
 principles and conditions for conducting toxicological
 experiments  (length  of  experiments,  selection  of
 doses of substances, research methods, interpretation
 of results  obtained, selection of safety factors, and so
   3.  The carrying out  of  organizational measures
 providing for  unified planning of scientific  research
 in the study of toxic  substances as applicable to all
 media and the simultaneous review of data obtained
 by  representatives of the  different   branches of
   The first step could, for example, be the establish-
 ment  of unified norms protecting the interests of all
 branches of the national economy in the rational use
 of reservoirs (ensuring sanitary conditions of water
 use by the population, the interests of fish protection,
 the preservation of hydrobionts,  the use of reservoirs
for watering agricultural crops, and so forth).  Ac-
cumulated practical experience in the use of sanitary
 and fishery MFC,  with the orientation being toward
a more rigid  norm from these two standards, has
shown the desirability and  soundness of  this ap-
 proach. Unfortunately, future realization of this  task
 has been made difficult by the lack of methodological
bases  for  the  normalization of MFC magnitudes in
hydrobiology and agriculture.

  There probably are different ways to estimate the
danger  from chemical substances upon their com-
plex admission to the body. However, the establish-
ment of the biological equivalency  (the isoeffective-
ness) of doses, and of concentrations, of substances
entering the body over different pathways is, as we
see  it,  of decisive  importance  in  developing  ap-
proaches to unified hygienic normalization.
  Various estimates have it that under contemporary
conditions, human health  is  threatened by  several
thousand  chemical substances,  very few of which
have been studied, relatively speaking. At the same
time, knowledge  of the degree of danger to be an-
ticipated from each environmental pollutant is ex-
tremely important.
  Despite  the success achieved  in the field of hy-
gienic normalization for environmental pollution, the
rates at which norms are  validated lag sharply behind
practical requirements. This  is what increases the
urgency for scientific development of methods for the
accelerated establishment of MFC for chemical pol-
   Accelerated normalization for  harmful substances
can be  accomplished by developing calculating  and
rapid methods. Formulas  for predicating MFC  in
atmospheric air,  and in  the waters in reservoirs,  in
terms of the physico-chemical characteristics of the
substances, of the parameters of their toxicity, and of
the norms established for other media, that are based
on  correlation and  regression analyses, have been
   Another approach to accelerated validation of hy-
gienic norms is based  on a study of the "concentra-
tion-time" and "dose-effect" relationships in a short
experiment with subsequent extrapolation of the data
obtained to an extended period of time.
   Research to validate the methodological conditions
for the  practical use of such an approach is presently
in progress along these lines  at the A. N. Sysin  In-
stitute  of  General and  Municipal  Hygiene  of  the
Academy of Medical Sciences of the USSR.
   Estimating  the danger from chemical compounds,
with consideration given to their intermittent effect,
is an extremely urgent problem in  hygienic normali-
zation.  We know that the concentration of  harmful
substances in  the environment is constantly under-
going temporal change, and as experimental research
shows,  the intermittent effect can,  in  some cases
diminish,   and in others strengthen toxic  effects  as
compared to the effect of  permanent concentrations.
   It is extremely important  to  the estimate of  the
intermittent effect to  establish the general  behavior
patterns in the development  of  the  toxic effect for
both the permanent  and   interrupted  effects  of
chemical  compounds, because it is  a practical  im-
possibility, given experimental conditions, to repro-
duce the  picture of the  variability  of the concentra-
tions of  the  substances polluting  the environment.
First among these general questions that should be
included are the quantitative dependence of the bio-
logical effect on the concentration of the substance
and the duration of its effect, comparative estimates
of the  permanent  and interrupted effect of harmful
substances on the body, quantitative estimates of the
capability of the substances and the  cumulation of
the effect, and so-forth.
   Wide-ranging special  research  in  validating the
principles and methods used to study the long-term
consequences (blastomogenic, genetic, gonadotropic,
teratogenic,  allergenic) of the effect of chemical pol-
lution is needed to resolve the question of the feasi-
bility of using these data for hygienic normalization.
Questions of the threshold nature of the types of bio-
logical  effects  of  harmful  chemical  substances  in-
dicated still have  not been developed sufficiently in
the theory of hygienic normalization. The question of
the feasibility of normalizing carcinogens in the  en-
vironment now has been resolved favorably, in prin-
ciple (on the basis of the MFC we can take  a dose
that will "cause"  an effect beyond the limits of
human life), but the feasibility of normalizing muta-
gens and allergens still is under discussion.  Hygienic
science must  develop this  most important field of
research more  effectively.
   One of the  key questions  of hygienic normaliza-
tion involves the problem of extrapolating toxicologi-
cal data from  animals to man. A lexicological  ex-
periment can be called biological modeling, because
there  can be  no  identity between  the bodies of
animals and man, and it  is this that makes it neces-
sary to resolve the question of the conditions under
which experimental data can be put  into hygienic
practice. The extrapolation methods used in hygienic
research  (direct transfer of data, the  use of safety
factors,  and so forth) are quite empirical in  nature.
   It has been established that the method that makes
use  of  direct  transfer  of  toxicological data from
animals, from  white rats, for example,  to man must
be used with care in order to validate hygienic norms.
The desirability of using "universal"  safety  factors
also raises doubts, because the value of the coefficient
of extrapolation must be found in terms  of the species
of laboratory animals, and of the specific properties
of the toxin being studied.  The method used to con-
vert doses per unit of body  surface of animals  and
man in order  to  grade  species differences with the
toxins also is in need of correlation.
   The validation  of the conditions under which ex-
perimental  data can be  extrapolated  from animals
to man is attended by great difficulties, but we believe
that study of questions concerned with  the compara-
tive sensitivity of man and animals to toxins, and the
recognition of  general behavior patterns in  species
differences  between mammals toward  the effect of
chemical pollution, has to be considered a promising
 approach to resolving this complex problem.

   Thus, the  development of  methodological  and
 theoretical research is the most important prerequisite
 for  increasing the scientific validation and reliability
 of hygienic norms. It is no accident that in accord-
 ance  with  the program for  scientific  collaboration
 between the USSR and the USA on the problem of
 "Environmental Hygiene," the  combined efforts of
 the  scientists of both countries  are concentrated on
finding  answers to precisely these current questions
of hygienic normalization.  The first  results of the
joint research show that we now have  great potential
possibilities  for  creating  an  even  more   perfect
scientific  methodology  for  perfecting legislation in
the field of protecting the environment, which is the
basis  for initiating measures that  will improve hy-
gienic conditions.

       Hygienic Normalization  Under Scientific and Technical
                                  Progress Conditions
                A. P. Shitskova, M. I. Gusev,* S. M. Pavlenko, I. L. Karagodina
  Scientific and technical progress is sharply chang-
ing the nature of the effect of society on nature, and
is bringing about changes in the biosphere. The pri-
mary factors affecting the biosphere are urbanization
and industrial, scientific, and technical progress. They
cause change to take place in the environment, in
atmospheric  air, water, soil, nutrition, and in  other
things, and the appearance of new factors, such as
vibration,  ultrasonics, static electricity,  electromag-
netic oscillations, and others.
  Control of the biosphere  under these conditions is
one of the most important tasks confronting  man-
  The classics of Marxism-Leninism considered this
problem to be a social one, right from the very be-
ginning. Control  of the biosphere  is a conscious
activity on the  part  of society, aimed  at regulating
life processes, including protecting the health and the
biological  perfection  of existing populations,  as well
as of future generations.
  The implementation  of measures designed to im-
prove the  environment requires the development of
quantitative  indices  for the  condition  of different
environmental factors  and  criteria  of  harmlessness
that ensure optimum conditions for man's (society's)
vital activities under predetermined social conditions.
  Hygienic normalization  during a period of rapid
technical development  is universal  for  all environ-
mental objects, and is brought  about by practical
demands. Scientifically developed quantitative indices
(maximum permissible  concentration, maximum per-
missible  value,  maximum  permissible  level,  and
others) were until  recently concerned mainly  with
individual substances and environmental factors.
  Research  in the course  of hygienic normalization
for  harmful  substances includes comprehensive ex-
perimental research  methods on animals, observa-
tions of people, and natural investigations of the state
of the environment.
  The whole arsenal of modern physiological, bio-
chemical,  pathophysical, physicochemical,  clinical,
and other research methods is used to study the bio-
logical effect of small  concentrations of toxic sub-

  • Institute ot Hygiene, Moscow
stances in order to provide hygienic  normalization
for these latter. Hygienic normalization, as a rule, is
aimed at establishing threshold and subthreshold con-
centrations of the substances or environmental factors
  The estimate of the interaction between toxic sub-
stances and the organism depends on the dose-time-
effect ratio. This means that all environmental factors
can become pathogenic if their duration and intensity
exceed the threshold level of the effect.
  The principles of hygienic normalization have been
perfected with the development of hygienic science
and  new  tasks,  such as recognition  of the conse-
quences of multifactor environmental  effects on  the
organism, have arisen before the  researchers in  the
modern stage. As a  result, in addition  to establishing
permissible  limits   for  individual   environmental
factors, questions concerned with the study of  the
combined effect of toxic substances on the organism
have become currently important.  We  know that  the
simultaneous effect of toxic substance  on the organ-
ism can be the same as the effect of each individually
(independent action), can be weaker  (antagonism),
or stronger  (synergism). Simple  summation (addi-
tive action) can take place in the latter case, when
the sum of the concentrations  of two  or more toxic
substances with a definite effect is equal to unity.
  Based on present data, and confirmed by experi-
mental research in the field of municipal hygiene  for
atmospheric air and water in reservoirs, there usually
is an additive effect, that is, the effect  of summation,
in the case of the combined effect of toxic substances.
  It is the opinion of I.  V. Sanotskiy that potentia-
tion is extremely rare  in the field of industrial  hy-
giene when  there is a lingering combination of  the
effect at the level of the threshold of lingering effect.
  Thus, the accumulated data from the experimental
study of the nature of the combined effect of harmful
substances in low concentrations entering the organ-
ism by whatever pathway have made it  possible to
formulate principles for  the normalization of  com-
binations of substances included in the corresponding
legislative resolutions.

   Hygiene  has  recently had to study the  combined
 effect of physical and chemical factors under produc-
 tion conditions and in populated areas.
   The  best studied of the physical  factors include
 noise,  vibration, ultrasonics, and temperature varia-
 tions. Their combinations with chemical substances
 can be  quite varied. The combined effect of physical
 and chemical factors differs from their isolated effect
 on the  organism. Thus, clinical and experimental re-
 search  has  established that local and general vibra-
 tion intensifies the toxic effect of heavy metals (N.
 A. Gordonova,  1967; L. Ya. Tartakovskaya, 1970).
   Experiments on animals  have shown that general
 vibration combined with  manganese,  mercury, or
 lead has a  more pronounced effect on some indices
 of the functional state of the central nervous system,
 metabolism, and others. New, distinctive, phenom-
 ena not noted when the effect is isolated sometimes
 will be observed.  However, changes pointing to the
 attenuation  of the mutual  effects of different agents
 can be detected, along with potentiation. Thus, vibra-
 tion definitely moderated the anemia-causing action
 of mercury  or lead, showing a direct effect on the
 hematopoietic processes in the bone marrow (L. Ya.
 Tartakovskaya,  Ye.  N.  Fresh,  A.  G.  Mal'kova,
   Manganese exhibits less of an effect on the delicate
 structure of the peripheral nerve-muscle endings, and
 the regeneration of damaged elements begins much
 more quickly as compared  to the isolated  action of
 manganese.  The data provided by Ye. M.  Neizvest-
 naya, L. G. Babushkina,  and  A. G. Gol'dePman
 (1972)  show attenuation  of the mutual effects of
 vibration and MnC2, as well as of silicon in lung
   The  combined  effect  of ultrasonics and ethanol
 intensifies the  biological  effect obtained from the
 isolated effect of these factors. Changes in the central
 nervous systems of animals  under the repeated effect
 of this complex under study were of the same nature
 as they were under  the effect of ultrasonics  alone,
 but in a more pronounced form (A. D. Shipachyova,
 1969). This leads to the assumption that the physical
 factor, that  is, the ultrasonics, is the lead component
 in this complex. Thus, reactions of the organism to
 the combined effect are ambiguous.  The  reactivity
 of organs,  and  of functional  systems, at  different
 levels can be distinguished by their special features,
 and the integral biological  effect is not the result of
 simple arithmetic  addition,  but reflects the specific
 differences  between  the reactive structure  of  the
   Certain  common  "critical"  functional  systems
 which, in the final analysis, determine the relation-
 ship between the  processes of pathogenesis in the
 course of the response reaction, also can be distin-
   Intensive   scientific  and  technical  progress  has
greatly  complicated  the questions confronting  hy-
 giene in recent years. The need arose to develop new
 methodological  approaches  to  making a  complex
 estimate of the effect of environmental factors. To-
 day, research is in progress along these lines to arrive
 at complex hygienic normalization  of  pesticides in
 environmental objects (L. I. Metdved', Ye. I. Spynu,
 et al.,  1969).  Some calculations  of the maximum
 harmless dose  for the  simultaneous entry of sub-
 stances from different media have been proposed (A.
 I. Korbakova, N.  I. Shumskaya, et al.,  1971).
   One of the possible methodological variants in de-
 veloping approaches to  complex hygienic normaliza-
 tion can be the use of  graphic  calculation  methods
 (N. I. Sidorenko, N. A. Pinigin, 1971, 1972).
   Attention also is being given to the  experimental
 study of the special features of the complex effect of
 toxic  substances  in  the  environment.  The  complex
 effect  of the substances cannot be equated to the
 combined  effect without  the  corresponding experi-
 mental verification. It can be assumed that the com-
 plex effect will  have its  own special features. This is
 so primarily because the same chemical substances
 will act on the different  receptor fields  in a manner
 that will depend on  the  pathway over which they
 entered  the body  (R. V. Anichkov,  1955; A. G.
 Bukhtiyarov, 1955), and will differ in the nature and
 rate  of adsorption, conversion,  and excretion  from
 the body (Ya. A.  Teysinger, 1959; I. L. Gadaskina,
 et al.,  1971).
   Special experimental  studies were made  at the F.
 F. Erisman Institute to  study the general behavior
 patterns  of this effect  by the most  widely  used
 chemical substances found in  organic synthesis pro-
 duction,  such  as  ethanol, cyclohexanone,  benzene,
 methanol,  formaldehyde,  carbon  tetrachloride, and
 other nonelectrolytic toxins  (S. M. Pavlenko, V. A.
   The scheme  developed for studying  the complex
 effect of substances in a continuing experiment pro-
 vided for revealing the effect of the toxins at the level
 of threshold and inactive doses  and concentrations.
 Maximum attention was  given  to the  selection  of
 common, pathogenetically meaningful, and the  most
 sensitive, specific tests and functional loads in order
 to seek out the special features  of the  effect of the
 same  substances when body entry  was over peroral,
 inhalational, and complex pathways.
   It has been  shown by the  example of the study
 made of the behavior patterns involved in intoxica-
 tion by nonelectrolytic substances  that  at  the  basis
 of the origin of their chronic intoxication  are me-
 chanisms that  affect the  central nervous system,  as
 well as some of the metabolic processes,  regardless
 of the entry pathway,  although  the formation  of
chronic  intoxication  did proceed  differently.  All
response reactions occurred earlier for  most of the
substances when entry was  via a  complex pathway
 than when the pathway was inhalational or peroral.

  However,  the  toxicity  of  the  nonelectrolytes
studied changed unidirectionally upon complex intro-
duction in the  continuous  experiment,  despite  the
fact that benzene, alcohols, cyclohexanone, and other
of the substances studied are  opposite in type  of
effect from  industrial narcotic-toxins, which  belong
to different groups in the system of nonelectrolytes.
  We, in our studies, paid special attention  to dis-
covering the breakdown in the body's adaptive mech-
anisms  (adaptations) to the effect  of the toxic sub-
stances studied when they entered via different path-
ways, using a set of functional tests. A comparative
estimate of a series of integral and specific functional
loads (static efficiency, a cold test, an alcohol test,
injection of a decisive dose of the substance itself,
anodization of  the brain, and others) was made for
this purpose.
  The experiments  showed that in the  presence of
even  negligible symptoms  of intoxication,  all  the
functional loads used yield a good effect, revealing
any change in the functional activity of the organism.
So far as the stage of apparent normalization  is con-
cerned, only  specific  pathogenetically  meaningful
functional loads reveal the latent effect of the toxin.
  The specific functional test for substances  with a
narcotic effect is anodization of the  brain.
  The studies  made showed that  the formation of
chronic intoxication proceeded differently when in-
dustrial nonelectrolytic  toxins at the threshold level
entered over different pathways.
  Basic  changes in the  indices for the functional
state  of the organs and systems  were noted  only
during the first three to four  months of exposure
when entry of substances was complex, as opposed
to separately (inhalation or peroral).
  The  state of nonspecifically increased  resistivity
appears in the  first weeks of the  experiment. The
stage of compensation  for  the  pathological  process
most usually takes three to four months to develop.
Data also were obtained which indicate the possibility
of the development in this case of latent phases of in-
toxication from the  toxins studied in shorter periods
of time as compared to the separate effects of these
same substances. This  fact  is of  scientific interest,
because it makes it possible to correctly estimate the
danger of chronic  intoxication, with  the complex
effect of environmental factors taken into considera-
  Study of the intoxication mechanisms makes  it
possible  to approach  the  development of  unified
methods for estimating  the biological effect of toxins
(nonelectrolytes)  when  they enter over  different
pathways (peroral, inhalational, and complex).
  Generalization of the experimental data helps re-
veal the general behavior pattern in the reaction of
the organism to the simultaneous entrance of harm-
ful  organic substances  (nonelectrolytes)  over  dif-
ferent pathways, and usually is expressed in the effect
of the summing of their effect.
  Along with the study of the complex and combined
effects of substances on the organism, attention re-
cently has been  concentrated on the development of
methodological questions with a view to ascertaining
the  behavior patterns that could lead to integrating
the  MFC for toxic substances simultaneously in food
products, water in reservoirs, atmospheric  air, and
other environmental  objects. Calculation  methods
based  on ascertaining  the correlation  relationship
between   different  parameters   of   toxicity  and
chemical constants were  developed in this connec-
  The development of the multifactor relationship
between  the parameters  of toxicity  of acute  and
chronic effects and the physicochemical indices for
substances normed in food products,  water in reser-
voirs, atmospheric  air,  and in the area of working
spaces,  is the  basis of  mathematical  modeling re-
  The use of parametric and nonparametric analysis
methods has made it possible to expose the correla-
tion relationship between the above-indicated indices,
based on which calculation formulas have been ob-
tained for use in finding the tentative value of the
permissible  content of toxins in  different media.
  On the other hand, the development of accelerated
methods for establishing the MFC for substances in
various environmental objects, based  on a  study of
the  special features of the biological  effect of toxins
and the exposure of common pathogenetically mean-
ingful indices of toxicity for different entry pathways,
was begun in a combined experiment.  This approach
permits the  development of unified methods  for es-
timating the biological effect of chemical substances
and makes  it possible to conduct studies simultane-
ously, and in parallel,  that deal with hygienic  nor-
malization of toxic substances in different media.
  Our data show that predicating the harmless  level
of  chemical compounds  in  different  environmental
objects  while combining  the use of  mathematical
modeling and detailed study of the behavior patterns
of the biological effect of toxic substances is a promis-
ing methodological direction to take in the integral
approach to hygienic normalization.
  Scientific  and technical  progress, created by man,
cannot  be considered as something that is  alien to
the biosphere. It simply is a qualitatively new stage
in its development, one that can  be  regulated from
the point of view of the interrelations between man
and nature.  Therefore,  we ought not consider the
presence  of changes occurring in the  environment
as a fatal inevitability accompanied only by negative
effects on the organism. It would be more correct to
consider  environmental pollution (of  atmospheric
air, water, soil, and others) as a phenomenon occur-
ring as a result  of what still are  imperfect  techno-
logical processes. All the  conditions  needed  to per-
fect these processes are  available in  the  socialist

society. Mankind today is  at the stage of a gradual,
intelligent, transformation  of the  biosphere  into  a
zoosphere. Therefore, the  activity  of the  hygienists
during the period of the scientific and technical rev-
olution should  be  directed at studying the effect of
the newly-forming environmental factors on the or-
ganism on a new scientific methodological base. This
permits developing multiprofile  complex indices in
accordance with which it will be possible to correlate
the permissible  parameters for  forecasting the  en-
vironment, working conditions, living conditions, and
the health of the population; to protect man's health
heredity against  the  defective action of mutations;
to  preserve  existing  genetic  information; and,  by
social reorganization, to promote the creation  of a
healthy, modern, society.
   In his report to the 24th Congress of the CPSU,
L. I. Brezhnev pointed  out that the consolidation of
the achievements of scientific  and technical progress
and of socialist management of the economy in our
country permits the establishment of rational forms
between nature and society.

                   Maximum Permissible  Human Stress1
                                        VaunA. Newill **
  Formulation  of sound environmental policies de-
pends upon the availability of adequate information
upon which to base regulatory decisions. Current en-
vironmental health research must  provide  data for
adequate assessment of health risks that arise from
environmental pollutant  exposure. Pollution  abate-
ment to reduce or negate these health risks requires
financial expenditures  and  possibly  even lifestyle
changes. Figure 1 is a simplified schematic diagram
that presents several of the  principal factors in the
decision-making process  concerning air pollution
control. It indicates  that the  degree of health protec-
tion attained is a function of pollution control costs.
The minimum  acceptable level of  health protection
is, at  the very  least, that level necessary to protect
from  death; and the  immediate regulatory  action
program adopted for  air pollution  control  should
certainly protect from  illness as well.1
  The  degree  of health  protection  to be selected
above the minimum acceptable level from  Figure  1
is a matter for political decision. The appropriate
authorities  must decide on  the level of health pro-
tection  desirable for  their  society.  Increments  of
health  protection  above  the minimum acceptable
level are generally purchased at ever increasing incre-
ments in control costs. The  zone in which increased
health protection (benefit) is obtained at increasing
control  costs (the cross hatched area in Figure  1)
can also be thought of as the region of social decision
making. The level of health  protection desired must,
of course, take into account  the existing air pollution
effects,  but other considerations are  also important,
including  general  social,   cultural  and  economic
factors,  as  well as  the  magnitude of  other  health
problems. In deciding where to spend limited money
resources,  the total set of risks that  man must bear
need to be considered  and the greatest efforts should
be  expended to reduce the largest  risks, be they en-
vironmental or other societal problems.
   Each regulatory action is  taken for society's bene-
fit. However, each  action  also has  a societal dis-
benefit  because it consumes  a certain quantity of the

            "TGION  IN WHICH

              TION VS. COST OF AIR
              POLLUTION CONTROL.
 society's resources for its accomplishment. Obviously
 there  must be  some  give and  take between the
 societal benefits and disbenefits. Decisions involving
 this process are difficult because the group to bene-
 fit may be different from the group that receives the
 disbenefits and  thus, it is  difficult  to make this  an
 equitable process.
   Another important  concept  follows from further
 consideration  of Figure 1. Infinite  health protection
 is unattainable,  thus society must either decide what
 level of health risk is acceptable, a  decision that will
 be reflected in  the  societal financial investment in
 environmental pollution control; or the decision will
 be made indirectly since the societal financial invest-
 ment in environmental pollution control will dictate
 the level of health protection to be  achieved.


   Environmental problems are identified in two gen-
 eral ways. One is by focusing  on  the environmental
 factors (agents) to which  the population is exposed.
  •Much of the content of this paper is based on internal EPA reports. Only those from which many passages were taken are cited. References
 other than EPA reports are cited.
  ••Special Assistant to the .Administrator, U.S. Environmental Protection Agency

 Another is by focusing on disease determinants and
   By such  considerations  many problem  areas  are
 identified. To decide which problem  areas  are  the
 most  important  some  criteria  must  be  applied.
 Factors considered in placing the  problems into a
 priority order for action include such considerations
 as:  (1) characteristics of the pollutant, e.g., ubiquity,
 expected levels  of exposure to the population, innate
 toxicity,  bioaccumulation and persistence; and (2)
 the pollutant's potential for playing an important role
 in public health  problems, e.g., affecting  the fre-
 quency, severity or trend pattern of a specific disease.
 Pollutants suspected as being related to diseases that
 are common, severe  and  increasing  in prevalance,
 should gain the highest priority for  regulatory  ac-
   Now  let's consider some issues in  the  detailed
 assessment of specific  problems.
   Integrated information from several disciplines is
 useful in  the health assessment of these problems.
 The major  disciplines  involved  are  epidemiology,
 clinical research and  the whole  set of experimental
 studies that  will be included  under the term  toxi-
 cology, being fully  aware that many other disciplines
 are  involved in these studies.
   Each of these discipline  approaches  is useful. A
 well-designed program .integrating the unique capa-
 bilities  and the  crosswalks  between  these disciplines
 can provide  a most satisfactory basis  for regulatory
 action.  Epidemiology can provide studies of popula-
 tion (communities or disease groups, current or long-
 term) exposure in  real life settings. The advantages
 of epidemiology are: the exposure is natural, there is
 no need for  extrapolation of data to the human, the
 most vulnerable groups  in the  population can  be
 studied,  and  both  current  and long-term  low-level
 exposures can be  evaluated.  The major problems
 relate to quantifying the exposure, to dealing with the
 many covariates, to obtaining dose-response data and
 to deciding association vs. causation.
   Clinical research  studies  can  be  used  to  gather
 human  data  on either normal or diseased  persons
 regarding absorption,  metabolism and excretion  of
 pollutants  and can  be used for indepth studies  of
 humans  accidently  exposed to high levels  of  pol-
 lutants.  These accidently-exposed humans  provide
 an opportunity to develop new study parameters and
 response  indicators.  The   advantages  of  clinical
 studies are:  the pollutant exposure is controlled  so
 that improved dose measurements are obtained; since
 each person can usually be  used as his own control,
covariates  are well controlled;  vulnerable  (highly
susceptible) subjects can be included in the studies;
cause-effect relationships are more easily ascertained;
there is no need for extrapolation to humans;  and
thus the derived information gives maximum input
into  standards. The  problems are that the exposure
 is artificial, there can be no long-term exposures and
 thus only acute  effects  are  determined, and  there
 can be real hazard to the exposed persons.
   Toxicologic studies  can use many  response sys-
 tems, such as whole  animal, isolated organs, cells or
 biochemical  systems. The advantages of toxicologic
 studies  are:  maximum dose-response data can be
 obtained,  though this  information is incomplete at
 the  low end of the curve; data acquisition is  rapid;
 cause-effect relationships are more sure; and mech-
 anism of response studies, such as kinetics of pol-
 lutant absorption, distribution, metabolism  and ex-
 cretion,  can be performed. While known quantitative
 exposure requirements  are most easily satisfied under
 controlled or experimental exposure  settings, appro-
 priate human  disease  models in animals have not
 been available and thus have not been evaluated in
 this manner.  Furthermore, laboratory experimental
 studies cannot provide complete  assurance  of dose
 effects because community exposures cannot be dup-
 licated in the laboratory. In addition, the difficulties
 of extrapolating  the data to  the  human  remain,
 particularly estimating  the threshold  of  human re^

 Pollutants, Response and Human Exposure

   "The  effects  of pollutants on human health de-
 pend on the  physical and chemical properties of the
 pollutant, on  the  duration, concentration and route
 of exposure and on  the human uptake and metab-
 olism of the pollutant.  Man's biological response is
 likewise  a function of occupational, psychosocial and
 climatologic  factors  and is tempered  by the  phe-
 nomvna  of tolerance and adaptation. These exposure
 factors underlie attempts to understand  the impact
 of pollutant exposure on human health.
   "The  physical  and  chemical  properties  of  pol-
 lutants determine  their  potential as a health hazard.
 These properties—including size, density, viscosity,
 shape, electrical  charge,  volatility,  solubility   and
 chemical reactivity—all affect the absorption, reten-
 tion  and toxicity of the pollutants. Many pollutants
 do not retain their original identities  after entering
 the  environment. Thermal,  chemical and photo-
 chemical  reactions  occur  when  pollutants move
 through  the environment  from source to receptor.
 These factors affect the final  physical and chemical
 state  at the point of  human exposure and help de-
 termine the toxic potential of the pollutants." •

 The Response Spectrum3

   Environmental pollutants can affect the health of
individuals or communities over a broad range of
biological responses. One can conveniently think of
five biological response  stages of increasing severity

as illustrated in Figure 2:  (1) a tissue pollutant bur-
den  not  associated with  other biological changes,
(2)  physiologic  or metabolic changes of uncertain
significance, (3)  physiologic  or  metabolic  changes
that  are clear-cut disease sentinels, (4) morbidity or
disease, and (5)  mortality. Boundaries between cate-
gories may occasionally overlap.  Furthermore, each
category  shows a range of responses rather than a
simple all-or-none phenomenon.
   At any point in time more severe effects, such as
death or chronic disease,  will be manifest  in rela-
tively small proportions of the population.  In very
few cases can  death or disease be attributed directly
and  solely to pollutant exposure. Death and disease
are  end  products  of  repeated  cumulative insults
(cumulative risks) from sources  such as  diet, ciga-
rette  smoking, physical inactivity,  infectious chal-
lenges, and accidental injury.  In general, the role of
environmental contaminants in the mortality or mor-
bidity  experience  of  a community is  difficult to
quantify  because  so  many other determinants of
death and disease cannot be adequately measured.
  The lower levels of the response spectrum shown
in Figure 2 are subclinical manifestations of pol-
lutant exposures. Larger portions  of the population
are affected to  these levels  of  response.  Patho-
physiologic responses  such  as  impaired mucociliary
clearance  and  bronchoconstriction, and  physiologic
changes  of uncertain significance, such  as  neuro-
behavoral responses, are more adaptable to  experi-
mental studies on  animals  or humans than is the
case with acute or  chronic disease and can be more
readily associated with specific pollutant  exposures.
Pollutant burdens are tissue residues resulting  from
pollutant  exposure.  Pollutant burdens  are highly
specific effects of exposure,  can be readily quantified
in population studies and may be  used as indicators
of environmental quality. If the bridge between the
lower and higher levels of the response spectrum can
be established, the disease  risk associated with pol-
lutant burdens or physiologic changes can be shown,
and ultimately the  role of pollutant exposure in the
total community morbidity  and mortality experience
can be defined.
                                         PHYSIOLOGIC CHANGES OF
                                         UNCERTAIN SIGNIFICANCE
                                         POLLUTANT BURDENS
                                 PROPORTION OF POPULATION AFFECTED
                               AIR POLLUTANTS, OCT. 3-5,1973; COMMITTEE ON PUBLIC
                               WORKS, UNITED STATES SENATE 93-15; p. 646.


   Some groups within the population may be espe-
 cially susceptible  to environmental factors. Notably
 these include the very young, the very old, and those
 affected by  a disease. Susceptibility, however,  may
 be temporary as  well as permanent. Inherited  ab-
 normalities such as alpha antitrypsin deficiency and
 abnormal  hemoglobins are examples of permanently
 altered sensitivity.  Temporary increased  sensitivity
 may  be  associated  with periods of growth, with
 weight reduction, with pregnancy and with reversible
   Diseases commonly result  from  complex  causal
 webs rather  than single factors.4 Environmental pol-
 lution may contribute a  number of  strands to such
 webs. Other strands  may arise  from such diverse
 origins as genetic  heritage,  nutritional  status  and
 personal habits. Moreover, pollutant exposure may
 alter  the severity of disease without  altering its fre-

 Exposure Response Matrix
   The  duration and concentration of pollutant ex-
 posure are measures of the total dose to  the human.
 It must be remembered  that the rate at which the
 total  dose  is received  may influence  response.
   Health effects of  an environmental pollutant may
 be either short-lived (acute) or relatively permanent
 and irreversible (chronic). Acute  or  chronic effects
 may  occur after a  single exposure to a hazardous
 substance.  This can be illustrated by acute radiation
 exposure  which can cause  acute radiation  gastro-
 enteritis and chronic leukemia. An air pollution epi-
 sode  may have similar effects though  the permanent
 sequelae of  acute  episodes have  never been ade-
 quately studied. Likewise, acute and chronic effects
 can result  from long-term exposure. For  example,
 excess acute  respiratory  illness  and chronic respira-
 tory disease  have  been repeatedly demonstrated in
 high air pollution exposure cities. Acute  effects and
 short-term  exposures are  less difficult to  study than
 chronic effects or long-term exposure. Moreover, the
 effects of dose rate, i.e., large dose in  a short interval
 vs. repeated  small  doses over  a  long period,  have
 seldom  been  investigated  systematically. Little effort
has been expended  on the monitoring of long-term
exposure and disentangling the causal webs under-
lying  chronic effects  of  pollutant exposure. Such
effort  has been hampered, however, by methodologic

Evaluating Exposure-Response Relationships
   Given adequate characterization of exposures and
health effects, many additional considerations  bear
on  the  scientific  validity of the  exposure-response
relationship. Hill5 has given an exposition of criteria
that  can  be  used  to judge  whether  an  observed
exposure-disease relationship is causal. Hill's criteria
 were  developed as guides  for  occupational  health
 studies.  With  minimal  modification,  however,  they
 can be applied to  general population studies. These
 criteria  are:  Consistency of observed  associations
 coherence of results,  plausibility of the  association
 and strength of the association. Brief descriptions of
 each of  these as well  as exposure response gradient,
 intervention, and control of covariates are included.

 1.  Consistency of  Observed Association:
   Consistency of  observed  association is, perhaps,
 the most important criterion. Does the health effect
 occur in various age,  sex and race  groups? Has the
 effect been repeatedly observed in different places,
 circumstances and  times? Even small differences that
 are not quite statistically significant bear great weight
 in  standard setting when the criterion of consistency
 is met. When the same effect is observed  in a variety
 of population groups under varying conditions and at
 different times,  the likelihood of a constant error or
 fallacy becomes  progressively less.

 2.  Coherence of Results:
   When  animal studies,  experimental  human  ex-
 posures, and  epidemiologic  data are coherent,  i.e.,
 they  all  demonstrate the same or similar health ef-
 fects of  exposure,  the bits and  pieces of  evidence,
 when  brought together,  form  a mosaic of health
 intelligence. By  reinforcing  results  obtained  in  one
 research approach with  studies in  another,  a  co-
 herent health  intelligence system will provide  scien-
 tifically  strong  and  readily  acceptable  guides  for
 costly air quality controls.

 3.  Plausibility of the Association:
   Initial studies may  uncover unexpected relation-
 ships between exposures and effects. Mere statistical
 associations must  be  rejected when  no  reasonable
 biological explanation, based on experimental  evi-
 dence, can justfy the association. On the other hand,
 when experimentation points to  a disturbed physio-
 logic process which may lead to  some clinical mani-
 festation, subsequent epidemiologic  studies designed
 to test such hypotheses are well grounded in biologic
 plausibility. New exposure-response associations  re-
 quire support from other disciplines before causal
 inferences can be readily defended.

 4. Strength of the Association:
  When disease frequency is nine to tenfold greater
 in  exposed than in  non-exposed  populations,  the
 exposure-effect relationship is extremely strong.  Re-
 lationships of this  magnitude  have  been found in
 studies of cigarette smoking  and respiratory disease
 including lung cancer  and bronchitis. However, pol-
lutant  exposures  are generally less  intense and  less
reactive than cigarette  smoke inhaled deeply into the
lungs.  Differences  in  exposure  between high  and
low pollution  neighborhoods seldom exceed factors

of two  or threefold in concentration.  At present
ambient  air  concentrations,  relative differences in
effects between high and low exposure areas are un-
likely to be as striking as ratios observed in smokers
vs. nonsmokers. However, for common and frequent
disease  events such as acute  respiratory disease,
relatively small differences in disease experience can
have a large and costly impact.

5. Exposure-Response Gradients:
  When a  stepwise increase in  exposure can be
associated wit ha stepwise increase in the frequency
of the adverse health effect, the evidence is  strong
for a cause-effect relationship.  Linear  relationships
over an exposure gradient became increasingly diffi-
cult  to  explain  by third intervening variables.  Re-
sponse gradients can be investigated in relation to
exposure gradients across  geographic areas,  differ-
ences in length of residence in high exposure areas,
and  migration gradients constructed  from various
combinations  of childhood  and adult exposures of
the same individuals.  Human exposures occur  nat-
urally over an exposure gradient, especially over  time
and  across  areas. Exposure-response  gradients ob-
viously can be easily created in experimental settings.

6. Intervention:
   Protection of health requires society to intervene
in public exposures to air pollution. This interven-
tion is  largely  based on observed exposure-health
effects  associations.  As desirable  air  quality  is
achieved, will the frequency of adverse health effects
be affected? If so, the causal nature of the exposure-
response association is strongly supported. The  high
cost of air pollution control warrants a national pro-
gram of community health and environmental sur-
veillance in those places where achievement of re-
quired air quality  will  require vigorous abatement

7. Control of Covariates:
   The  causal nature of an  exposure-response as-
sociation is  convincingly exposed  when, after the
effects of known  covariates are first displayed, in-
creased disease risk within  covariate classes  can be
clearly  demonstrated  in high exposure  populations.
For example,  in any studies of chronic bronchitis,
prevalence,  smokers and males show more  disease
than nonsmokers and females  respectively.  An air
pollution-chronic bronchitis study  should  reveal the
above smoking-sex differences  in prevalence rates,
thereby  assuring readers that the study has internal
consistency.  If smoking-sex specific groups in  high
exposure neighborhoods have excess chronic bron-
chitis,  the  hypothesis that  air pollution exposure
causes excess chronic bronchitis is considerably more
convincing  than if the smoking-sex covariates  were
not  analyzed. Most epidemiologic studies of air pol-
lution require similar analysis of excess disease risk
within covariate categories, with particular attention
given to age, sex, smoking, socioeconomic level and
duration  of  residence  at  current  location.  When
covariates are  systematically analyzed for relation-
ships to  the  health  indicator under study, residual
excesses  in disease  frequency  can  be attributed to
area differences in pollution exposure with a reason-
able degree of  confidence.6

  The need  for regulatory action  is predicated on
the demonstration of an effect at the levels of a pol-
lutant to which the popular  is or  can be predicted
to be exposed.  The kinds of control options available
to prevent such effects and to choose among are en-
vironmental  standard setting, registration, certifica-
tion, licensing, limiting use,  banning and economic
incentives such as effluent charges or taxes. For sim-
plicity, the only option that will be address is en-
vironmental  standard setting.

Environmental Standard Setting
   An environmental standard  in itself is a complex
issue.  The  standard  is the  maximum  permissible
level of  exposure of the  public  to a pollutant per-
mitted for a  specified period  of time. For a pollutant
that is  only present in the air, the environmental
standard is the primary ambient air quality standard.
However, when the pollutant  is one where  human
exposure comes not only from the  air, but from the
food and water as well, the environmental standards
become a set of standards, each representing an allo-
cation of  a  portion of  the  permissible exposure
through  each  of  the media from which exposure
comes. No such environmental standards have been
set in the U.S.A.  to date.7
   The actual permissible level of exposure permitted
must be decided in  some philosophical  framework.
At the present time the -framework varies somewhat
by medium of exposure and  by effect of exposure, in
some instances by  legislative mandate, and in others
by differing  beliefs of those  responsible  for the pro-
 gram. It certain is the  scientist's role  to  be in-
terested  in these problems and to  supply a coherent
and rational basis for the framework  within which
 regulatory decision-making can proceed.
   Certain other concepts are useful to consider when
 discussing standard setting,  such as  threshold dose,
 dose-response, extrapolation of data from animal to
 man, and combined effects.

 Threshold Dose

   A biological effect may not be  observed until the
 dose reaches a certain level. This  level is called the

 threshold dose and it may be defined as, the mini-
 mum  dose  required to produce a detectable effect.
 The concept is important from both a practical and
 a theoretical  point  of view, since a  true threshold
 implies that below a given  dose there is no adverse
 change whatsover with regard to toxic effect of the
 substance studied; this allows a safe limit or standard
 to be specified. As one uses more sensitive responses,
 thresholds decrease. For example, illness frequently
 is a more sensitive measure of response than death,
 and both will be preceded by physiologic  changes
 heralding the  onset of disease. For many pollutants,
 such as ionizing radiation, there may be no threshold
 for the response.3
   The existence of a threshold may be due in part to
 the build-up in man of tolerance to the particular pol-
 lutant.  Tolerance represents the  ability of  man  to
 endure pollutant exposures without apparent ill ef-
 fects. The level of tolerance to environmental agents
 may be directly related to a  number of characteristics
 including age, sex, and nutritional state. The concept
 of adaptation signifies an increase in tolerance with
 long-term low-level exposure to a given adverse en-
 vironment.  Adaptation is   characteristically related
 to the stressful components  of the environment. The
 ability to adapt varies in a  population and is deter-
 mined  by   anatomic,  physiologic  and  biochemical
 characteristics of individual organisms.


  Operationally the threshold concept is being used
 in standard setting  activities in  the  United States
 regulatory agencies. However, many persons, finding
 that definitions for words such  as "safe level," "no
 effect level" and "virtual safety" (among others) are
 being  used  to satisfy their intellectual recognition
 that such absolutes  do not exist, are unhappy be-
 cause the use of these terms gives the general public
 the implication of safety as an absolute. Thus, the
 concept of  acceptable risk  is being introduced and
 hopefully environmental agents soon will be assessed
 in terms of relative risk rather than as safe or unsafe.
Dose Response
  Dose-response data extracted from either  com-
munity or experimental studies is crucial for the de-
cisions that must be made. However, when the infor-
mation is available, as it rarely is, it has been  gath-
ered in animals at  rather high exposure  levels and
needs to be  extrapolated to man who will be ex-
posed at lower levels.  Man, however,  will generally
be exposed in greater numbers and for longer periods
of time so that low-level risk can be  manifest. We
urgently need more specific research into the issues
of extrapolation so that better decisions can be made.
 Since  dose-response information is  frequently lack-
 ing, other techniques need to be considered.


   Studies of laboratory animals  have been used to
 assure that the toxicity risk from an environmental
 chemical is acceptably low. Such assurance  should
 be given  before  a chemical is introduced into  the
 environment in a fashion where there can be human
 exposure. However, relating animal studies to pos-
 sible effects in  man  poses difficult  and practical
 problems.  As  more  chemicals for  which there is
 sufficient  toxicity testing  are  introduced into  the
 environment where man can have similar exposure,
 we can learn more about the validity of the testing.
 Until  that  time  we  rely  on  such  information  as
 ". . .  cancers  in laboratory animals are essentially
 the same  as human cancers and with a single pos-
 sible exception, all  known human  carcinogens  are
 carcinogens in  laboratory animals, laboratory animal
 studies seem to predict for man. Thus,  for ethical
 and practical  reasons, data derived  from  use  of
 laboratory  animals for toxicity testing is  the foun-
 dation of efforts to protect  the  public from the pos-
 sible  harmful effects of new and old chemicals in
 the environment."
   The normal sequence  of animal  tests of a new
 chemical agent begins with  studies to determine  the
 mechanism  through which laboratory animals  re-
 spond to a compound, the nature of metabolites,  the
 distribution of the parent compound, the metabolism
 in the tissues  and organs, and  the  rates and  routes
 of elimination  of the  compound or its derivatives.
 Comparison of the similarity of the  results of these
 tests can  be made among  various  animal species,
 thus laying the groundwork for prediction of  the
 exposure events in man.  Attempting to systematize
 this  process is a prime area for research. Also, it
 must be remembered that this  approach is most
 useful  for  observing effects that  occur soon after
 the compound  is  administered,  but is less useful  for
 observing subtle long-term effects.
   When attempting to bridge the gap  between non-
 human and human toxicity  one must recognize two
 steps involved in the  extrapolation of  laboratory
 toxicity data to man. First, the extrapolation of what
 might be called the average or  median mouse  to  the
average or median man. This consists of extrapola-
 tion from the average or even the most sensitive one,
 two or three laboratory animal  species  to an average
man living under  conditions with a commonly  en-
 countered genetic make-up.  The second step requires
 identifying and allowing for variability  in the human
 population. The median mouse to median man extra-
polation is the  easiest  step.  Biomedical research  re-
 sults are beginning to illuminate the differences and
 similarities between  species and are  beginning   to

provide a rational basis for extrapolation. The  sec-
ond  step,  allowing  for variability and diversity—
both genetic  and environmental,  is much harder.
  There is,  then,  a basis  for comparison of the
median mouse to the median rat to the median dog
to the median man. More and more patterns that are
useful for extrapolation to man are being  recognized
and can be identified in  the course of  the  study of
the pharmacological disposition of a chemical. Most
of the differences that have been  observed suggest
that man is  more  sensitive than the usual experi-
mental animal, and this must be  kept in mind when
developing safety factors.
  The following principles were stated in the Wein-
house and Rail8 communication as this  subject re-
lated to  carcinogenesis testing:
  1. The major principle that must  be accepted if
we  are  to deal at all with long-term  assessments of
toxicity in man is  that effects in animals,  properly
qualified, are applicable to man.
  2. Methodologies do not now  exist to  establish a
safe threshold for long-term exposure  to toxic agents.
  3. The exposure of experimental animals to toxic
agents in high doses is a necessary  and valid method
of assessing  carcinogenetic hazard to man.
  4. Agents  should be assessed in terms of relative
risks rather than as safe or unsafe.

Combined  Pollutant Effects
   Physical-chemical  interactions  occur  among the
pollutants  in the  environment which in turn  alter
the biological activity of the contaminants as well as
the reactions within the tissues of man and animals.
The resulting bioeffects may be synergistic, additive
or antagonistic, resulting in a reaction whose magni-
tude is  greater, equal to, or less  than the sum of
the individual constituents.
  One  of the most recent  and best  demonstrations
of  synergism of two pollutants was presented by
Bates  and Hazucha in  October,  1973.9 Figure 3
shows  the effect  on four  measures of  pulmonary
function of 0.37 ppm of SO2 and 0.37 ppm of ozone
exposure independently, and  then the  enhancement
of  effects  when  both gases are present simultane-
ously. It is interesting to note that the effect of the
two gases  administered  simultaneously  is greater
than the sum of the effect of each individually; thus
a synergistic effect has been demonstrated that might
account for  episodes in the U.S.A., Netherlands and

Least Case and Worst Case Range Estimates6
   Derivation of range estimates  based on least case
and worst case assumptions is another  way to de-
velop  a workable plan upon which action  decisions
can be based. In least case assumptions,  quantitative
assessment of exposure or  response  is made on the
assumption  that  current  exposures  are not  repre-
sentative of long-term trends or that adverse  health
responses should  first be attributed to all  known
covariates, and only residual excesses of illness fre-
quency  be  attributed to  pollutant  exposure.  For
example,  in  the frequently-encountered  situation
where high  exposure and low  socioeconomic status
geographically coincide, the effect of low  economic
level on illness frequency would be identified first.
Any excess illness which could not be accounted for
by economic level would  be quantified  as a residual
effect. After  all covariates were considered in turn,
the final  residual excess  would be called   an air
pollution-related  health effect.  Least case estimates
attribute the smallest possible effect to  pollutant ex-
posures, do  not  allow for interaction  between co-
variates and  exposure, and give a maximum quanti-
tative estimate of human exposures associated  with
adverse responses.
  Worst  case assumptions attribute adverse health
effects first  only  to  covariates which are  known  to
be  strong determinants of disease  frequency,  such
as  cigarette  smoking in  relation to chronic bron-
chitis. But covariates which are not well founded  as
determinants of illness frequency are eliminated from
final analysis, and air pollution exposure is assumed
to have  contributed to the relatively larger residual
in excess illness  frequency. Likewise, if information
on  past  exposures is of low quality or unavailable,
current exposures are assumed to represent past ex-
perience, and chronic disease frequencies  are calcu-
lated as  a function of exposures at current levels.
Worst case  assumptions, therefore, give  minimum
estimates of exposures associated with adverse health
responses, and tend  to maximize the proportion  of
disease frequency attributable to pollutant exposure.
   The truth may lie  at either end of the quantitative
range  which can be derived  from least case and
worse  case  assumptions.  When health intelligence
cannot  give precise quantitative information,  the de-
cision maker should be provided with least and worst
case range estimates. At this point, the  degree  of
control  becomes a  function of other policy  con-
siderations, including control costs,  alternate  control
strategies  (and  the  health effects  of these), the
severity of magnitude of the  effect, the population
at risk, etc. Failure to present range estimates leaves
less room for control options  and forces decisions
based  on one set of numbers derived from arbitrary
interpretations about study results.

Least  Cost Protective  Standards'
   Air quality criteria supply  the  existing rationale
for  standards. The process of standard  setting  re-
quires policy decisions concerning protection  of pub-
 lic health at least cost to society. Sound quantitative
exposure response data allows the policy maker to
make  clear-cut  decisions which can  be defended.









      0.37 ppm SO2 (N = 4)

      0.37 ppm  O3 (N = 3)

      0.37 ppm S02+O3 (N = 4)
                                       2.5 0
                0.5       1.0      1.5
                                               TIME, hr
            Proceedings of the Conference on Health Effects of Air Pollution, Oct. 3-5, 1973; Committee on
            Public Works, United States Senate 93-15, p. 534.

           This figure shows the effect on four measures of pulmonary function of 0.37 parts per million of
           SO2 and 0.37 parts per million of ozone independently, and then the enhancement of effect
           when both gases are present simultaneously.





                                                                                                  ; 50






When  range estimates are broad due to inadequate
health  intelligence one of two possible kinds of error
may be made.  The resulting standards could be too
lenient and not protective enough  or they  could be
too strict  and excessively costly for the real benefit
derived. Thus,  society must pay a price for not gen-
erating adequate environmental health information.
It must also be remembered that generation  of health
information itself can be costly and that in  some in-
stances it  may  be less costly to overcontrol  than de-
velop the  specific information required.
  Margins of  safety  built into  standards are judg-
ments required to bridge the gap between the inade-
quacy  of  health intelligence  and the need to  stop
continued  exposure to hazardous pollutant levels.
Greater degrees of uncertainity generate larger safety
margins. Unfortunately control costs usually increase
exponentially as exposure is  limited  more  severely.
                                          The health benefit  from the  additional degree  of
                                          control  may be insignificant or actually  negative if
                                          overly stringent controls cause health  disbenefits,  as
                                          could occur if  scarce resources are  diverted from
                                          health care or  protection to unnecessary pollution
                                            The function of a health intelligence system in the
                                          standard setting process can be graphically displayed
                                          in the form of marginal cost curves (Figure 4). The
                                          true social cost of pollution is equal to the  sum  of
                                          the  cost of control and the health and welfare cost of
                                          exposure. Health costs of disease, and more  espe-
                                          cially of physiological dysfunction, cannot be readily
                                          estimated with current scientific knowledge. Health
                                          and  welfare costs increase  with  higher  exposures,
                                          while control costs increase as exposures are lowered.
                                          True  social costs of pollution are minimal where the
                                          two  marginal cost  curves intersect. If society will

tolerate  some  pollutant-associated  excess  health
costs, curve AD (Figure 4) may represent this social
preference. On  the other hand,  if society places  a
very high premium on preventable disease or reduc-
ing risk  of disease, curve A'D' (Figure 4) may well
represent this attitude. On both  curves, the points
B  or B' represent the lowest pollutant exposure as-
sociated with adverse health (or welfare)  effects.
Under the low health cost assumption  (curve AD),
society will accept the health costs  (and associated
adverse  health  effects) represented by the vertical
distance between B and  C. Under the  high cost as-
sumption,  society will not allow any adverse  health
effect caused by exposure and will require control to
point B',  where  high marginal  cost of control  is
equated with  derived health benefit.
   Excessively   stringent   standards   are  shown   at
points A and B under the low cost assumption and
at point A' under the high assumption, while too
lenient standards  are reflected in point D under the
low assumption and  C'  and D* under the  high as-
sumption. The  least cost standard,  in  terms of true
social costs, is at point  C  under  the  low health
cost  assumption  and at point B'  under  the  high
assumption. Least cost standards protective of health
require adequate quantitative exposure-response in-
formation,  knowledge of control  costs and range
estimates of health cost of pollution effects.

  Even range  estimates of pollutant related health
costs are difficult to derive. Many direct and  indirect
health  costs must be  considered,  including:  Im-
mediate and delayed health effects of short-term and
long-term exposure;  the  contribution  of  pollutant
exposure to the occurrence  and severity  of major
public  health  problems such as acute and  chronic
respiratory diseases, heart  disease,  cancer and con-
genital defects; and adverse health effects of control
strategies.  While  these estimates  are formidable
tasks, failure to make the estimates will prevent even
the possibility of  achieving  least  social cost  stan-
dards,  except  entirely fortuitously.  Required annual
reports of air  pollution control costs clearly  warrant
better  and more quantitative health effects data and

                          COST OF
                                     POLLUTION CONCENTRATION

                 LEAST COST STANDARD: C OR B'


 concerted efforts  to  convert health effects  to health
   Recently the National Academy of  Sciences was
 asked to review the  health basis for the ambient air
 quality  standards. One  part of that  review  was  a
 Conference on Health Effects  of Air Pollutants that
 was  held  on  October  3-5,  1973.10  All  existing
 U.S.A.  ambient air  quality  data  were presented  as
 least case, worst case and best judgment values.


  1. WHO: Air Quality Criteria and Guide  for Urban Air
    Pollutants. Wld. Hlth. Org. Techn.  Rep. Ser.  1972, No.
  2. Newill, V. A.: PSAC Briefing on  the EPA Air Pollu-
    tion  Health  Effects  Research  Program,  Washington,
    D.C. May 22, 1972. This briefing  was  based on many
    in-house  reports  from the  Division of  Health  Effects
    Research, NERC-RTP,  EPA, North  Carolina.
  3. Message from the President of the  United States Trans-
    mitting the Report of the Department of Health, Educa-
    tion  and Welfare  and  the  Environmental Protection
    Agency on the Health Effects of Environmental Pollu-
    tion, Pursuant to Title V  of Public Law 91-515. 92nd
    Congress,  House  of Representatives Document  No.
    92-24 I.February 1, 1972.
 4.  MacMahon, B.;  Pugh, T. F.; and  Ipsen, J.: Epidemi-
    ologic Methods.  Little, Brown and Company,  Boston.
    Massachusetts, 1960, pp. 18-21.
 5.  Hill, A.  B.: The environment and  disease: Association
    or causation. Proc.  Royal Soc. Med. 58:295-300,  1965.
 6.  Shy,  C.  M.:  Health intelligence for  air quality stand-
    ards. Presented  at  the Meeting of  the President's Air
    Quality Advisory Board, St. Louis,  Missouri, March 27,
 7.  Newill, V. A.: Nature and source of pollutants.  Pre-
    sented at the  American  Academy  of Pediatrics  Con-
    ference,  Evanston,  Illinois, June 11, 1973.
 8.  Weinhouse, S. and  Rail,  D.: Personal communication.
 9.  Bates, D. V.  and Hazucha, M.: The short-term effects
    of ozone on the human lung. Proceedings of the  Con-
    ference on  Health  Effects of  Air  Pollutants, NAS,
    NRC, October 3-5,  1973, pp. 513-540. U.S. Congress
    Document Serial No. 93-15, November 1973.
10.  Finklea,  J.: Conceptual  basis  for  establishing stand-
    ards. Proceedings of the Conference on Health Effects
    of Air Pollutants, NAS, NRC, October 3-5, 1973, pp.
    619-668. U.S. Congress Document Serial No. 93-15,
    November 1973.

 Maximum Permissible Human Stress Pollutants with Multiple
          Pathways:  Ionizing  Radiation,  Asbestos and Lead
                                      John H. Knelson *
  All human activity is associated with a degree of
stress; that is with a degree of risk to the health
and welfare of the human  organism. Only recently,
however, has man begun  to contemplate seriously
the degree of stress and the  risks associated  with
rapidly evolving technology. Initially, these concerns
were focused directly at the most obvious site of risk,
the workplace itself. Now, concepts from industrial
hygiene and medicine are serving as important bases
for development of the  more  general field of en-
vironmental  hygiene.  As technology becomes more
complex and pervasive,  the problems of  environ-
mental hygiene also become more complex and more
pervasive; obviously then, regulatory decisions based
on considerations of environmental health have  in-
creasingly significant  social consequences.
  Assessment of the influence of environmental fac-
tors  on human health is one of the most important
components of comprehensive environmental analy-
sis. The measurement of human health, however, is
in itself a complex  and  incompletely understood
task, and it becomes increasingly complex when one
considers  the multiplicity of environmental  stressors
which may act upon the body. It is essential, there-
fore, that  some  simplifying concepts be employed to
organize and interpret environmental health effects
data. How do we define "Maximum Permissible Hu-
man Stress"? How do we determine environmental
standards  for pollutants  that permeate the environ-
ment,  enter the human body,  and exert  influence
through multiple mechanisms?  These are  parts  of
the bigger question, "How  should we modify or re-
direct  our technological  development to  assure that
environmental hazards  are  maintained  at  a level
that represents  the best  balance between acceptable
risk and acceptable cost?"

   The  determination of an association between  an
environmental agent and a putative health  effect re-
quires that the exposure concentration in the environ-
ment  be measured  accurately  and unambiguously.
This rather self-evident prerequisite to health effects
studies is frequently not met. Although conceptually
simple, it is in practice often very difficult to meas-
ure with acceptable accuracy the pollutant dose to
which a population is exposed. This problem is com-
pounded when the agent  exists in several forms in
the environment  and enters the  human organism
through a variety of pathways  and from a number
of sources. Even when good  chemical  analysis is
possible, determination of the actual dose delivered
to the individual is difficult. Environmental monitor-
ing at a particular point gives a relatively poor esti-
mate  of the spatial variability  of pollutant concen-
trations within an area—and the exposure over time
of an individual residing  in that area is even more
   Some  materials,  such  as  lead,  accumulate in
human  tissue.  That  accumulation, a  function of
dosage integrated over some period of time, can be
expressed  as "pollutant  body  burden." This total
body burden, the total quantity of a substance dis-
tributed within body tissues or  physiologic compart-
ments, cannot be partitioned into contributions de-
rived from each  of the multiple portals of entry, nor
does  body burden correlate  consistently with  re-
sultant health effects.
   In the  case of asbestos, monitoring  of exposure
becomes excruciatingly difficult for not only is  par-
ticle composition crucial, but size and aerodynamic
characteristics are  also  important.  Although "fer-
ruginous bodies" are found in the sputum of asbestos
workers,  no  way has been developed  to associate
these bodies  quantitatively with the intensity of en-
vironmental exposure. With ionizing radiation,  con-
venient personal monitors—film badges—are avail-
 able. But they do not measure that fraction of  total
 body dose inhaled  or ingested as  radionuclides.  In
 general, then, measurement of the dose of  any en-
 vironmental  pollutant an individual receives is still
 technically difficult.
  •Acting Director, Human Studies Laboratory, National Environmental Protection Agency, U.S. Environmental Protection Agency.

   Measurement of health effects attributable to en-
 vironmental pollution  is  also fraught with  many
 methodologic  difficulties.  Definition of health and
 description of statistically significant deviation from
 the norm is greatly complicated  by the multitude of
 factors that determine the health status of any pop-
 ulation. These difficulties  in  the measurement  of
 health  effects pervert  the  meaning  of threshold.
 Though paying homage to the true definition, in the
 real world we set a threshold level at the point where
 available health effects  data  fail to show  any sig-
 nificant dose-response relationships. Historically, the
 more data accumulated the lower the threshold level
 is set. In this  context, the  threshold, when not just
 a statistical artifact, is purely an  operational concept
 which  contains  more  information concerning  the
 level at  which  our uncertainty begins than about the
 underlying  reality.
   As the tools for measuring dose as well  as those
 for measuring  human response are improved, it be-
 comes  possible to describe a continuum of effect
 down toward zero dose. Thus, even a very small en-
 vironmental insult  probably has a very small but
 measurable impact on human  health. It is  then no
 longer a question of "What is a safe level?" Rather,
 the question becomes "What level of risk is accept-
 able?"  The concept of threshold limit value is  re-
 placed with the much more complicated concepts  of
 Cost-Benefit analysis, which allow us to define Ac-
 ceptable Risks. It is no longer sufficient for the scien-
 tist to provide a threshold value and suggest a margin
 of safety. He must provide the decisionmakers with
 the best possible objective description of health  ef-
 fects as related to dose, and also  with an estimate  of
 his degree  of  uncertainty  concerning that relation-


   Implicit  in the description of  Dose-Response re-
 lationships is the ranking by relative priority of the
 described relationships.  A comprehensive  control
 strategy  requires knowledge not  only  of the well
 described health effects of a particular environmental
 agent, but knowledge  of the importance of that agent
 relative to the  importance of other risk factors, not
 all  environmental,  which  may  lead to  the  same
 health  effects.  The  risk attributable to  a particular
 environmental agent must be judged in comparison
 with the risks attributable  to other factors,  such as
with eating, drinking,  smoking, physical  activity, and
mode of life in general.  Only in  this way may we
efficiently employ society's finite resources; the cost-
benefit ratio should be minimized not just with re-
spect to all activities  which come under  the broad
umbrella of Public Health. It should be clear, how-
ever, that control activities will  not invariably  be
 directed at the most important risk factors, as risk
 factors are not all equally amenable to control.
   Risk factors not only sum up, they may also inter-
 act. It is well known that smoking increases the risk
 of industrial  asbestosis.  Ionizing  radiation  in some
 forms, smoking, and asbestos fiber inhalation are all
 associated with various types of lung cancer. Yet, we
 are  almost totally ignorant of the  relative contribu-
 tion of these factors, much less the possible  inter-
 actions among the  three. More recently,  we have
 begun to suspect that low level lead intoxication and
 certain kinds of ionizing  radiation may act syner-
 gistically to produce some forms of mental retarda-
 tion. We are only beginning  to explore the relative
 importance of environmental costressors.

   Humans are not uniformly susceptible to environ-
 mental stress. The historic episodes  that first drew
 worldwide attention to  the lethal  consequences  of
 severe air pollution affected primarily the very young,
 the aged, and the  infirm.  Those early observations
 were  evident even to the untrained.  Since then, more
 careful documentation of range of  susceptibility has
 been  possible.
   In epidemiologic studies, the strongest correlations
 with pollutant exposure have been  seen in the inci-
 dence of respiratory infection  in children, in the in-
 creased number of attacks  in asthmatics, and  in the
 increased intensity  of symptoms  in  people with
 cardiopulmonary disease.
   Ionizing radiation is known to have  an especially
 deleterious effect on the developing  mammal, but we
 have  no firm evidence that any subsets of the adult
 population  are  particularly  susceptible.  Excessive
 lead intake, by whatever pathway, is associated with
 impaired  central  nervous  system  development  in
 young mammals, and  may be  particularly harmful
 in people of all  ages with some types of kidney dis-
 ease.  Particular  susceptibility to inhaled or ingested
 asbestos in the absence of other environmental co-
 stressors has not been  described up to now.

   Whereas there is a  range of susceptibility within
a population,  "spectrum of response" refers to the
various ways an individual can manifest the effects of
environmental  stress.  The  spectrum of response is
usually a function of pollutant concentration, dura-
tion of exposure and the presence of costressors such
as exercise, thermal stress, or other coexisting pol-
lutants. We have somewhat arbitrarily classified the
spectrum into  categories ranging from the mildest
to the most severe. They  are: (1)  pollutant body

burden, (2) changes of uncertain significance,  (3)
pathological changes, (4)  morbidity, and (5) mor-
tality.  Because the proportion  of  any population
falling into any category  is greatest with (1)  and
the least with  (5), it is evident that the concept of
"range of susceptibility" is closely related to that of
"spectrum of response." Combining the concepts of
dose, spectrum of response,  and range of  suscep-
tibility allows  us to construct  a three-dimensional
dose-response  surface from which both risk and the
proportion of the population at risk can be estimated
for each dosage level. This kind of prediction is the
final goal of environmental health effects research.
We are trying to answer the  question, "How many
individuals in  each category  of  our  population are
subjected to what levels of risk when subjected to
pollutant concentrations within a given range?"

  Comprehensive environmental analysis as a foun-
dation for comprehensive environmental control re-
quires not only a firm health effects data base, but
interpretation of the data in a manner useful to those
responsible for establishing the control strategy.  The
concepts necessary for that interpretation have been
described. Assembling the proper variables into an
exposure-response  matrix should provide, for.each
environmental stressor,  a point of departure  for
eventually assessing the  Maximum  Permissible  Hu-
man Stress  attributable to pollutants  with mulitple
  The exposure-response matrix uses dose,  estab-
lished by environmental monitoring  and modeling or
by  pollutant burden  analysis,  as  the independent
variable. The dependent  variable is  the Spectrum of
Response. To these are  added  an intervening vari-
able, the Range of Susceptibility. Without this-third
covariate, such a  plot is simply the classic  dose/
response relationship.  With the "z" axis representing
the Range of  Susceptibility, we  have  additional in-
formation of use in total assessment  of risk. It allows
us -to relate the degree of response at a  particular
dose to specifically susceptible population  subsets.
  Estimates of Maximum Permissible  Human Stress
can be derived from  the exposure-response matrix
in combination with a sector of the  relevant popula-
tion sizes for each population subset. From the set
of outcomes, .a weighted total must be  generated, the
set  or sector of weights expressing the importance of
the outcome.  These  weights are necessarily judg-
mental. However,  their  use with the exposure-re-
sponse matrix does at least provide  a tool  for  apply-
ing judgmental decisions  objectively and  uniformly
in  developing the cost/benefit  information  that is
needed for- establishing environmental standards.

  Three examples  of environmental  agents  with
multiple  pathways for entry into  the  human and
multiple  mechanisms  of action will  be discussed
briefly to elaborate some of the principles for estab-
lishing maximum permissible  human  stress. These
examples have been chosen primarily because they
illustrate the problems involved in dealing with pol-
lutants of multiple pathways, not because the prob-
lems with these  pollutants  have been  solved.  It is
anticipated,  however,  that  analyses of these  prob-
lems will demonstrate  some helpful first steps in ar-
riving at answers when one is  dealing with compre-
hensive  environmental analysis and control.

Ionizing Radiation
  This  example  of an environmental stressor,  or
category of  stressors,  is particularly important be-
cause it is probably the one for which we have more
health effects data than any other. Thus, some im-
portant  analytic,  conceptual, and control philosophy
precedents  have  been set.  Many  prototype  pro-
cedures  for environmental analysis  and  control have
been developed  by a generation  of scientists who
devoted their careers  to studying  the  problems of
ionizing radiation. It is an environmental stressor of
multiple pathways par excellence for it is transported
through  all  media  of  the  biosphere,  entering the
human via all imaginable portals.
  It is significant to note that  the most recent  sum-
mary of effects on populations exposed to environ-
mental ionizing radiation begins with a  careful com-
prehensive analysis of nature, sources, and transport
mechanisms  of the  environmental stressor. Without
this  analysis, estimation of  health effects is inade-
quate. Too frequently, toxicologic evaluation of other
environmental stressors is  attempted  without suf-
ficient data  concerning pathways  from the various
sources  to the human recipient.
  Biologic effects of ionizing  irradiation  are classi-
fied  according  to  influence  on  genetic  material,
growth and development, and somatic health. Genetic
effects predominated early concern, and have be-
come increasingly  important  as  more  has  been
learned  of the molecular basis  for  disease. Increased
knowledge of genetic effects has not lead to a greater
precision of  dose-response  estimates,  however,  as
new complexities have been discovered.  The  prin-
ciple of dose-rate independence has lost some cred-
ibility as mechanisms for cellular repair of radiation
damage become  better understood.  However, dose-
rate delivery during an organism's relatively  short
developmental period must still  be considered in
establishing life-span standards because of the greater

 susceptibility of the  developing  organism to effects
 of ionizing radiation. Important analogies with other
 environmental stressors emerge as one considers the
 problems  of establishing other dose-rate standards.
 Averaging  times  for  most pollutant standards are
 established with crude dose-rate effects data, if any.
   Many  environmental  stresses  have more  pro-
 nounced effects during developmental stages of the
 organism,  as does ionizing radiation, and this serves
 not  only  to emphasize the range of susceptibility
 concept, but also to  raise the problem of  pollutant
 interactions. Other environmental agents,  especially
 heavy metals,  drugs, and food additives are known
 to be preferentially distributed to certain tissues dur-
 ing  the development period and  these may exert a
 synergistic  effect  with other environmental  factors
 which must be recognized in a comprehensive analy-
 sis of maximum permissible stress.
   The somatic effects of ionizing  irradiation,  e.g.,
 cancer induction, provide, perhaps, the most striking
 example that multiple pathways and interactions of
 environmental  stressors must be considered  in estab-
 lishing acceptable risk levels for each pollutant. Many
 pollutants  are  carcinogenic.  They  permeate the en-
 vironment, entering the host  by all  portals. Their
 effects may well be additive or even synergistic. They
 represent the most important  challenge to  compre-
 hensive environmental analysis.
   The comprehensive  environmental  analysis  of
 ionizing  radiation has been more extensive  than for
 any  other  environmental stress.  Yet,  even  with the
 extensive data  available, establishing the exposure/
 response matrix as described is  very difficult. Esti-
 mates of acceptable risk are possible only  within  a
 range  of one order of magnitude. Although genetic,
 developmental,  and somatic effects  have  been  ex-
 plored, the genetic effects of radiation  are most  im-
 portant in  estimating acceptable  risk.
   Four  techniques  have  been  used  to  calculate
 genetic risk:
     (1) Risk relative to the effects of natural back-
         ground radiation;
     (2) Risk  for specific genetic conditions;
     (3) Risk  for severe malformation and disease;
     (4) Risk  in terms of overall ill health.
   Natural  background radiation  averages about 10
 mrem per year. However, there is considerable vari-
 ation in  this figure depending on geographic loca-
 tion, type of dwelling, and altitude. Varying concen-
 trations of naturally  occurring minerals that emit
 radiation account for most  of the geographic  dif-
 ferences. Structures built of stone containing these
 minerals  will subject  the inhabitants  to more back-
ground radiation than wooden buildings. Screening
of cosmic (mostly solar) radiation by the atmosphere
decreases with  altitude. Thus, man throughout  his
existence has  been exposed to  radiation,  and the
effect of  that natural  or background  level serves as
 a  convenient  denominator  for expressing relative
 risk. If  man accepts a range of risk, depending  on
 the factors  described, from background  radiation
 approaching zero to that over  200 mrem per year,
 it  can be argued that he should  accept  additional
 unspecified risk the same  order of magnitude as-
 sociated with environmental stressors or man's cre-
 ation. "If the  genetically  equivalent significant ex-
 posture is kept well below this [background] amount,
 we are assured that the additional consequences will
 neither differ in kind from those which we have ex-
 perienced throughout  human  history  nor exceed
 them in  quantity" (BEIR Report,  1972). This esti-
 mate, based only on an estimate of dose and none
 of health effect is more philosophical than scientific,
 but the  advantage of avoiding all  the  assumptions
 of human radiation genetics.
   Risk  estimates for specific  genetic abnormalities
 can be made by comparing the current incidence of
 observed genetic conditions  to  those expected from
 increased radiation.  There are  no directly applicable
 human data, so those from experiments with mice
 must be  used. Chronic radiation to developing mouse
 sperm cells  results  in  about  0.5  x 10~7  recessive
 mutations per rem per gene. Developing oocytes are
 much more resistant. Therefore, the  average for both
 sexes is  less than  10~7, and must because of the un-
 certainties in the data  be estimated as somewhere
 between  10-8 and 10~7 per rem per gene.
   Spontaneous mutation rates in  the  human are
 estimated to be less than 10-". This is  10 to 100
 times the rate  induced  per rem. Thus, the ratio  of
 radiation-induced  to naturally  occurring mutations
 is 1/10  to 1/100, and the additional dosage neces-
 sary to double the spontaneous mutation rate  is 10
 to  100 rem. This is strictly an  "order of magnitude"
 estimate. More subtle  arithmetic  might place the
 estimate  at 20  to 200 rem for  a "doubling dose."
   Another  statistical approach  to  the  concept  of
 "doubling dose" utilizes data  from Hiroshima and
 Nagasaki. The observed death  rates in  children  of
 exposed  survivors  does not differ  from  matched
 population controls who were not exposed. However,
 if some  assumptions concerning average acute pa-
 rental dose (100 rem each)  and liveborn death rate
 from "spontaneous"  genetic abnormalities are ac-
 cepted, the chances are less  than 0.10 that the true
 death rate was as great  as  one percent higher  in
 children  of irradiated parents. Thus,  100  rem  at
 most resulted in an effect twice that occurring  with-
 out  additional  radiation,  and  the  "doubling dose"
 would be 50 rem. This is within the estimate of 20
 to 200 rem for "doubling dose" made on the  basis
 of entirely different assumptions.
   To estimate the impact  of  induced genetic im-
 pairment on the overall risk  of  severe malformation
and disease, one must know  the increase in induced

genetic impairment and the contribution of such im-
pairment to disease in general. Using  the  estimate
of 20-200 rem as the "doubling dose,"  the increase
in relative  mutation risk is in the range of 0.005-
0.05 per rem.  The continuous exposure rate of 5
rem per 30 years (or 170 mrem per year) would, in
equilibrium, cause an  increase of  2.5-25  percent
in the overall incidence of genetically-related disease.
But what fraction  of malformations and other rec-
ognizable disease  states  are  mutation-related? Esti-
mates of the total burden of human disease related
to  hereditary  factors are   virtually  meaningless.
Therefore,  even  the  best  estimates  of radiation-
related  genetic abnormalities  (or spectrum of  re-
sponse)  mean little until better data concerning  the
range  of  susceptibility  within the population  are
   Risks in terms of overall  ill health  are  included
because  the other estimates  deal with more specific
disease states that  could result in an under-estimate
of  radiation risk to health in general.  Again, only
order of magnitude relative  risk estimates  are pos-
sible with  available data. The most reasonable esti-
mate  is  that 20  percent of  all ill health may have
some genetic component. If  20 rem is  the  mutation
rate doubling  dose, an exposure of 5 rem  per gen-
eration (5 rem per 30 years  or 170 mrem per year)
would increase the total ill health burden over a
long period of time by 5 percent. If 200 rem is the
doubling dose, the increased  burden would be  0.5
   Thus, with a  variety of assumptions and with a
relatively  large  data base,   the  standard  for  the
multiple pathway  environmental stressor—ionizing
radiation—is set at 170 mrem per year. This stan-
dard  has  been  established  without the refinement
of the  three-dimensional  exposure-response matrix
because of the many difficulties cited. However, many
attempts have been made to provide the data  neces-
sary.  The  inadequacies are  logistic, not conceptual.
As more is learned of ionizing radiation effects,  the
matrix  can eventually be completed  to provide a
more  accurate  estimate of maximum permissible
human stress.

   Although associated  historically only with occu-
 pational exposure, over the past ten years consider-
 able evidence has  accumulated which associated as-
 bestos  disease  with  nonoccupational  exposure  as
 well. This evidence also suggests  a spectrum of re-
 sponse ranging from  those  observed  in persons ex-
 posed in their occupations to those observed in per-
 sons only indirectly exposed by family contact or by
 neighborhood location.
   Factors which complicate studies of the effects of
 asbestos air pollution include:
    (1) The long lapse period between exposure
 and illness (often 20, 30 or 40 years). The long
 periods between exposure to asbestos and develop-
 ment of mesotheliomas  that have been observed
 could  be indicative  of  a  breakdown of human
 defenses in elderly people.  This suggests a range
 of  susceptibility, i.e.,  individuals  past the age  of
 asbestos workers who live in the vicinity of emittor
 industries  may  be affected by acute  or  chronic
 exposure to relatively low levels of asbestos.
    (2) Lack of knowledge  concerning the signifi-
 cance  of intensity of exposure. Although there is
 evidence suggtsting a  continuous  spectrum of re-
 sponse for lung disease,  there  are no  data  for
 establishing  dose-response  relationships for  the
 development of cancer. This dilemma emphasizes
 the difficulty inherent in establishing standards for
 a substance of  multiple pathways  and different
 pathophysiologic mechanisms.
     (3) Size and variety of asbestos fibers. Whereas
 the occupational exposure limit is based on counts
 of  asbestos fibers >  5^i in length,  this  counting
 technique has  little  usefulness  in ambient  sit-
 uations. Fibers emitted into the ambient air break
 up into  fibrils  the detection of which requires the
 utilization of electron microscopy. Consequently,
 equivalent quantities of asbestos  pollution cannot
 be detected in  occupational and ambient situations
 by determinations of numbers of particles  >  5n
 in  length. When asbestos  is  implanted into the
 pleura of rats,  cancer is produced only by fibers
 greater  than 5/x in  length, and  usually  at  least
  40/i in length.  Fibers less than 5/t in length appear
  to be less carcinogenic.  However, this is not  in-
  terpreted as indicating that shorter fibers are com-
  pletely  harmless. Preliminary studies of  asbestos
  pollution in water indicate that by far the greater
  portion of the asbestos consists of small particles,
  although some larger fibers do occur. Hence, the
  problem of asbestos pollution in water may be
  quite  different  from the problem of airborne  as-
  bestos pollution.
     (4) The synergistic  effects of cigarette  smok-
  ing or  exposure to  other concomitant  air  pol-
  lutants.  In  industry,  insulation  workers  who
  smoked  had eight times the  risk of  lung cancer
  of smoking workers  exposed to  asbestos and 90
  times the  risk  of  nonsmoking  workers not ex-
  posed to asbestos.  Comparable increased  risks
  may be experienced  by smokers who live  in  the
  vicinity of asbestos  industries.
  Since timely and accurate measurements of total
quantities of asbestos  in the ambient air  would be
impractical, or impossible, in most areas, protection
of the general population must rely on control of
emissions. This  heavy  reliance  on  emission control
is  similar to the strategy applied for ionizing radi-
ation. Considering the  complete inability to quanti-
tate  the effects  related to  specific exposure,  plus

 the repeated association of fatal  disease with non-
 occupational exposure,  it would  appear desirable
 that emissions be restricted to the limits compatible
 with the best available control techniques. Such con-
 trol recommendations should not be construed to be
 recommending  elimination of all  asbestos from the
 ambient air. Nonoccupational illness  has been  as-
 sociated almost exclusively with indirect occupational
 exposure  or residence in the immediate  vicinity of
 an  asbestos source. There is no  evidence  that the
 small number of fibers to which the general popula-
 tion is  exposed affects health or  longevity;  this  is
 similar  to the situation with "background" ionizing
   With available data, how  much of  the exposure-
 response matrix can be  filled  in  for asbestos? The
 first problem is environmental monitoring. Asbestos,
 a hydrated mineral silicate, occurs in several  forms.
 Most widely  used  in  United  States'  industry is
 chrysotile, a magnesium silicate. Other forms include
 iron,  sodium, and  calcium as well  as  magnesium
 silicate.  Virtualy nothing is  known of the relative
 toxicity  of these forms of asbestos from data per-
 taining  to human  exposure,  and  very  little com-
 parative animal toxicology is available.  Because of
 this,  monitoring virtually never   includes  specific
 analysis of  composition.  Instead,   the airborne as-
 bestos filaments are collected  on impactor plates or
 filters, and the particles sized and counted by micro-
 scopy. The relative  toxicity of longer fibers  (greater
 than  5  micrometers) and motes   (nonfibrous par-
 ticles) is a question of continuing concern. Although
 some  studies do show a  deleterious effect of motes,
 their toxicity is apparently much lower than that of
 the longer fibers. Whereas pulmonary pneumoconiosis
 and silicosis due to  paniculate  silicate  inhalation
 have  much in common with pulmonary asbestosis,
 it seems only the  fibrous  form of asbestos  is  as-
 sociated with gastrointestinal carcinoma  and  meso-
 thelioma. With  respect to airborne pathways,  oper-
 ational monitoring systems as well as particle or fila-
 ment  sizing  and  counting techniques provide less
 than adequate data.  These may be improved as auto-
 mated optical devices are developed and qualitative
 determinations using such techniques as microprobe
 analysis  are  employed.  With  respect  to  ingestion,
 especially from  drinking water that has been  trans-
 ported through asbestos pipes, the  monitoring  prob-
 lem  is even more complicated. Again, the source of
 asbestos  fibers associated  with  gastrointestinal  carci-
 noma  and mesothelioma is  ambiguous. It is  difficult
 to know how much  of  the  ingested dose is first  in-
 haled  and then swallowed after  tracheobronchial
 mucocilliary  transport,  and how  much may  come
 directly from contaminated drinking water. The only
 way this question can be  answered for exposed hu-
 man populations is  with  much more  sophisticated
and  comprehensive  environmental  monitoring. One
 can  appreciate, therefore, the  difficulties in  char-
 acterizing environmental  exposure to  asbestos  for
 the purpose  of establishing the  exposure-response
    The spectrum of  response for  asbestos exposure
 has been mentioned.  In all cases, however, the health
 effect is disabling and eventually fatal for some indi-
 viduals. Therefore, all effects lie at the extreme end
 of the response spectrum, and large weighting factors
 are applicable.
    Range of susceptibility estimates are made diffi-
 cult by the inadequate assessment of  population at
 risk  and poor  understanding of the  importance of
 environmental costressors.  Tobacco smoking seems
 the most  obviously  implicated  costressor. But ab-
 sorption  of  carcinogenic hydrocarbons with  subse-
 quent desorption after inhalation has  also been sug-
 gested  as an additional cofactor. Trace element con-
 tamination of the  mineral matrix may also  play a
 role in the overall toxicologic assessment of asbestos.
 In general, the assumption has  been made that  ef-
 fects of asbestos exposure are dose-rate independent
 and the concept of "fiber years per cubic centimeter
 of air" has been employed. From estimates of pop-
 ulation risk, the probability of  early  signs of lung
 disease is less than one percent for 100 fibers years
 per cc. This would be equivalent  to four fibers per
 cc for 25 years or two fibers per cc for 50 years ex-
 posure. There are virtually no data to estimate size
 of population at risk, or  range  of susceptibility, for
 asbestos-related gastrointestinal carcinoma and meso-
 thelioma. Thus, as with ionizing  radiation, standards
 must be set as low  as possible  because of lack of
 health  effects data and necessity for  maintaining a
 reasonable and  prudent safety  margin. A great deal
 more information is  necessary before the exposure-
 response matrix for  all pathways and  effects  of as-
 bestos can be substantially filled out.


   Environmental standards for lead which have been
 proposed,  take  into  account more information on
 spectrum of  response  and  range  of  susceptibility
 than is available for  most other pollutants of multi-
 ple pathways.  There is  little controversy over the
 basic toxicology of  lead  compounds.  Toxicity  of
 lead has been recognized since antiquity. It has most
 usually  been  associated with oral  ingestion,  how-
 ever,  and only more  recently has airborne lead as-
 sumed  greater importance. The  concern with lead
 as  a  pollutant of multiple pathways  has  emerged
 since the introduction of organic lead compounds to
 automotive vehicle fuel because of their antiknock
 properties. There  has been some  controversy over
 the relative importance of inhaled versus ingested
   As usual,  environmental  monitoring has  neces-
sarily preceded  the  design of good health  effects

studies. There is now little argument that the air of
urbanized  regions has higher lead concentrations
than that of rural areas. Tentative results indicate
an amelioration of air quality in  urban areas where
significant  decreases  in  automotive lead  emissions
due to reduction of lead in gasoline have  occurred.
Finally, the contribution of airborne lead to ingested
lead via dustfall merits comment. As  with ionizing
radiation  and asbestos,  lead  represents a  complex
environmental pollutant of several related pathways.
  The spectrum of response for lead, unlike that for
ionizing radiation or asbestos, has been studied from
(1)  pollutant body  burden through (5)  mortality.
Pollutant body burden is usually  expressed as blood
lead concentration. In  addition,  however,  consider-
able animal data are available to describe  lead dis-
tribution in various body tissues  and compartments.
The validity of extrapolation  of these data  to the
human is still not completely certain, but some cor-
roborating information from analysis of autopsy tis-
sues is becoming  available.  A change of  uncertain
physiologic significance  most clearly related to in-
creased lead  body  burden  is found  in,decreased
activity of red blood  cell  aminolevulinic  acid de-
hydrase. This enzyme is associated with hemoglobin
synthesis, but is also  present in other tissues such as
the central nervous system where its function is not
understood. Changes in activity  of this enzyme cor-
relate well with changes in blood  lead concentrations,
but  this is of uncertain physiologic significance be-
cause  lowered enzyme levels are not unambiguously
related to any specific diesase state. Changes in renal
function associated with higher  exposures  represent
a specific precursor of morbidity. These changse are
usually associated with industrial exposure or with
lead ingestion. Animal studies, however, suggest that
very low  exposure  to lead  results  in  observable
changes in renal microstructure, and that  there is a
dose-response  relationship continuing down  toward
zero with  no  demonstrable  threshold.   Moreover,
there is evidence  suggesting that repeated low-level
exposure may alter  pathways of detoxification and
excretion  without any signs  of  toxicity. Finally, of
course, the overt  morbidity and mortality of central
nervous system  and renal  disease related to lead
intoxication is well-known. Less well  appreciated or
understood at this time is the possible subtle inter-
action  of  lead with  many other environmental fac-
tors, including ionizing radiation, to produce mental
retardation in children. One sees for lead, therefore,
 a wide spectrum of response irrespective of the path-
 way into the human.
   Whereas there has been fairly good understanding
 of the relationship between dietary lead and result-
 ing blood  lead or pollutant burden  level, only  re-
 cently have  reasonably good data for  respiratory
 lead uptake become  available. Studies exposing men
 to carefully controlled low air lead provided data  for
a rather well-defined respiratory lead uptake model.
Population studies have resulted in comparable esti-
mates of the relationship of air  lead  to total body
pollutant burden.
  Females residing in urban area and exposed to
higher air lead levels were found to have significantly
higher blood lead levels than those living in suburban
areas where air  lead  levels were lower.  In Phila-
delphia,  11 percent of women living in the urban
area had blood  lead  levels of 29 /ig/100 gm or
greater. The average  urban air  lead concentration
there was 1.67 /*g/m3 during the period of  the study.
Similar findings in Chicago  were:  3.4  percent of the
urban women studied had  blood lead levels of 29
n%/100 gm or greater with an average air lead of
1.76 /ig/m3. In New York, however, only 1.4  per-
cent equaled or exceeded the 29/ig/100 gm level at
mean air concentration of 2.08 /*g/m3. Extrapolating
these percentages to the entire  population base of
these urban areas would, of course,  involve a large
number of people with blood levels that can be  con-
sidered excessive.
   Another  recent study has found significantly in-
creased  blood  lead levels  in women living near  a
well-traveled roadway compared to those  living  fur-
ther away. Air lead exposures were particularly well-
quantitated in this study because measurements  were
made  on the front porches  and  inside the homes
where the women lived. The  average air lead  just
outside  the homes nearest the  highway was  4.6
Mg/m3  and that inside  the home was 2.3  i»g/m3.
The air lead levels just outside and inside  the homes
 122 meters (400 feet) from the highway  were  2.24
Mg/m3 and 1.57  Atg/m3, respectively.
   Epidemiologic evidence indicates that while mean
 blood lead levels in populations are not significantly
 elevated by exposure  to aid lead of about 2 ng/m3,
 the frequency distribution of these blood lead values
 do differ so that significant urban-suburban differ-
ences do exist, and large numbers of people do have
 blood levels equaling pr  exceeding 30 ^g/100 ml
 level at average  air lead exposure levels  of 2/ig/m3
 and less.
   With respect to range of susceptibility,  in the  case
 of lead it is becoming evident that children, the fetus
 and  newborn in particular,  constitute  a  specially
 susceptible group. This observation is certainly re-
 lated to the increased incidence of overt lead poison-
 ing in children due to their eating lead-based paint.
 Not equally appreciated, however, is  the importance
 of their  eating  lead-containing  dust  and dirt  from
 atmospheric fall-out.  Recent evidence indicates that
 children may absorb considerably more of their oral
 lead intake than do adults. Although opinion is far
 from unanimous on the mechanisms  of lead absorp-
 tion from the respiratory tract,  a significant fraction
 of that inhaled  and deposited there  may eventually

find its way to the gastrointestinal tract via mucocil-
liary tracheobronchial clearance. Greater enteric ab-
sorption of lead by  children is  thus important from
several aspects. Finally, the respiratory dose per unit
body weight may well be greater for children  than
adults because their level of ventilation is greater at
rest and their level of activity is higher.  There is no
evidence  that their  detoxification  and  excretory
mechanisms for lead are proportionally  accelerated.
Neither is there any to suggest it is not.  Taking into
account reported  overt  clinical toxicity in children
of  lead at blood  levels  of  40—50  //.g/100 ml,  the
other considerations discussed above, and the most
minimal of safety  margins, an acceptable blood lead
concentration for  children  of 30/ug/lOO  ml  seems
prudent  and  reasonable. Because of the  reported
high  correlation   between  newborn  and  maternal
blood levels, expectant mothers should also be pro-
tected from achieving blood lead levels of 30 /ug/100
ml  or higher.
  It can be concluded, therefore, that a prudent and
reasonable upper limit for blood lead concentration,
one with a certain  margin of safety, that can be used
as a criterion for  setting an air quality  standard is
30  /ig/100 ml. This  level applies to a large fraction
of the population; that  is,  newborns, children and
expectant mothers.  Adults  may  tolerate, with a
margin  of safety,  levels  somewhat higher than this.
Because it  is  not feasible to  implement  different
ambient  air quality  standards for children and  ex-
pectant  mothers as opposed to those for the rest of
the  population, the lower value  must be chosen.
   The  exposure-response matrix for  lead  can be
 completed with a degree of confidence not yet pos-
 sible  for  most pollutants. Imperfect as it is,  blood
 lead  concentration  nevertheless serves as  an  im-
 portant index of integrated lead exposure from  dif-
 ferent pathways over relatively long periods of time.
 Comprehensive  environmental  standards  for  air,
 food  and water can  be  established  to  maintain the
 quality  of the environment above that related to ac-
 ceptable risk.

   Assessing the influence of environmental agents on
public health is a difficult  multifactorial problem.
Composition and concentration,  sources,  distribu-
tion,  and bioavailability of pollutants must be de-
termined before  meaningful  estimates of maximum
permissible human stress or acceptable risk are pos-
sible. As comprehensive  environmental analysis gives
improved estimates of  existing dose and dose-rate
factors, biological effects data become more relevant.
Spectrum of response  and  range of susceptibility
provide the  tools for establishing an  exposure-re-
sponse  matrix   from  which  some  objective  cost/
benefit analyses can be  drawn. The problem of as-
sessing  combined effects  due  to  pollutants with
multiple  pathways has barely begun. It will  be best
pursued using firm principles and precedents estab-
lished in evaluating single pollutant effects.

      Complex  Analysis of the Environment,  Approaches to a
      Determination  of the Permissible  Loads on  the  Natural
          Environment and to a Justification for  Monitoring
                                        Yu. A. Izrael *
  Two interrelated  questions arise,  given the  ex-
tremely varied anthropogenic effect on the natural
  (1) What is the state of the biosphere today (on
a global,  ecosystem,  regional, or local scale); is this
a crisis state?
  (2) What is the possible, permissible load of the
different  effects, taken in the existing complex, on
the  environment on different scales?
  Only the sequential development of a  system of
observations, of predicting the state of the environ-
ment, and of estimating the  existing and predicted
state of the environment,  can answer the  first ques-
  This report, and the symposium as a whole, are
devoted to an attempt to answer the second question.
The result of the answer to the second  question is
primary to estimating the state of the environment,
and is, therefore,  the scientific basis of monitoring;
it is precisely this result that should be the basis for
the optimization of the relationship between man
and the environment,  and the basis  for monitoring
and controlling the quality of the environment.
  Most of the work  in determining permissible loads
up  to this point has been limited primarily to the
sanitary  and  hygienic  approach  (in  developing
permissible loads on  man), and to the economic
approach (the  fisheries  approach,  for  example).
Secondary norms and standards too have been de-
veloped in which the possible consequences of effects
on  vegetation have  been  taken into  consideration.
  However,  it is  apparent  that  generalized  ap-
jHoaches to the  development of  permissible  effects
on  the population, of the assemblage of the system
as  a whole must be considered;  individual  sources
must be  taken into consideration, as must  sources
in this region, or system, as  a whole, and the com-
plexity of their effects, possible interactions.  More-
over, it is desirable  to find criteria to use to select,
or define, the different variants of permissible effects
  We shall, in making  a complex analysis of all
effective factors, estimate the final result (from the
point of view of its acceptability) in terms of the
magnitude of the damage. The latter can be broken
down  into ecological, economic,  and  moral  (es-
thetic). Recreational damage can be included in the
latter two kinds of damage. The kinds of damage
indicated are interrelated to a considerable degree.
Approaches to  determining the extent of the damage
will be described in what follows.  It is desirable to
adopt in advance  certain strict limitations  (for ex-
ample,  a total ban on any ecological or esthetic dam-
age to  unique  objects, or, in general,  any changes
despite the fact that damage from a change at the
particular point in time is not in evidence), as well
as the  unacceptability or unjustified (irreversible)
ecological changes in most natural objects, and so

  Table  1 explains the  kinds of  damage that can
be done, and establishes  certain links between them.
  Obviously, there is little chance of estimating es-
thetic damage  at  this time. There are certain ap-
proaches associated with an estimate of the time and
money man spends to satisfy his  need for esthetic
values  that can be taken to make  such an estimate.
Such  expenditures are  growing  steadily, and  will
continue to grow  in the future.  Improvement,  or
preservation, of man's health will,  at the same  time,
yield to evaluation.

  The moral (esthetic)  damage is determined to a
considerable degree by an upset in man's habits, in
his perceptions, emotions, and in the concepts he has
formed during his upbringing, and as  result of the
education he receives during his lifetime.

   We shall try to establish a link between the magni-
ture of the source (emission, emissions)  and the
tude of  the source (emission, emissions)  and the
scope of the ecological  damage  (factual  A*) within
the framework of some limited area.
  •First Deputy Chief of Main Administration of Hydrometeorological Service, Moscow

                                                  Table 1
       Ecological damage
                                              Economic damage
                                                                                  Moral (esthetic) damage
  I. Unjustified—irreversible con-
                                        Direct  losses  in the
                                        losses in the future
 II. Reversible consequences
    a.  deterioration in the con-
       dition of individuals, pop-
       ulations, ecosystem
    b.  response without  deteri-
       oration in condition
       —animals,  plants

                                        Direct or potential losses in in-
                                        crease in biomass (harvest)
                                        Possible migration with possible
                                        economic  and esthetic losses
                                                                              Disruption of usual perceptions
                                       	Recreational damage with possible economic and esthetic losses
   For this we must know:
   (1) the function of  the  sources (in space  and
     R, t*>=   y y  y
                 j   1
            is the different factors, ingredients, of
            ith orders within a homogeneous class;
            is the nature of the  medium (air, soil,
            fresh,  sea,  or subsoil  water,  and  so
            is the nature of the heterogeneity (pol-
            lutant, radiation,  heat);
   (2) the geophysical laws of distribution (function
F)  in different media. The concentration (or value
of some factor) ^jn in the different media is
           = F[Q(R, t*), v, KT, wz, t-t*]    (2)
             is the rate of horizontal movement  of
             an impurity (wind speed, flow, and  so
             is a  coefficient characterizing turbulent
         w   is a coefficient characterizing the verti-
             cal rate of transfer  from one  medium
             to another  (sedimentation,  precipita-
            tion,  and so forth);
      t-t*  is the  elapsed time  between emission
             and time;
The possible transfer of part of a substance from one
medium  to another during distribution (migration)
   (3)  the chemical (physical)  laws tor the conver-
sion of a given ingredient (factor) into another
               is the concentration (or value of the

          factor) of the ingredient at which the orig-
          inal ingredient, or factor, can be converted
          during distribution, or  accumulation;
       is is a  coefficient characterizing the conver-
   (4) the  distribution  of  organisms  in   space
   m  is their level; it is desirable  to know Mm,  the
distribution of  their weight  relationship from'  the
point of view of their ecological  value, importance,

determining their  role in system  stability.  Nm(R,t)
takes into consideration the distribution of individual
parts of  the organism of a  given specimen  (popula-
tion) in  space  (sometimes this is  very  important, as
would be the case, for example, for plants, the roots
of which are in the ground, while  the above-ground
organs are in the air).
  The magnitude
                                                                     (R, t)dRdt =
                                                      is an integral magnitude characterizing an m-popula-
                                                      tion as a whole.

                                                        The importance of  the  factor Nm(R,t)  must be
                                                      stressed, because the factual  distribution or  organ-
                                                      isms  in time and space determines to a considerable
                                                      degree the ecological damage of an effect on the en-
                                                      vironment  (because  this distribution characterizes
                                                      the possibility of contact between the organism and
                                                      pollutants, or other factors).
                                                        For example, in estimating the factual situation in
                                                      cities  (determination of damage to the population)
                                                      knowledge  of the  distribution of pollutants  is not
                                                      enough. This  distribution must be compared with the

distribution of the organisms in time and space in the
particular city (including according to height);
   (5)  t   is the measure of the biological  effect

(damage) for the  given  organism (level m) for the
effect of a factor  (ingredient)  (1), entering the or-
ganism (or making contact)  from the j medium. At
the same time, it is very important to take into con-
sideration the entrance of the particular ingredient
fram all j media. The ingredient can affect different
organs, so can differ in the effect produced as well.
   The magnitude  t, generally speaking,  depends on
the magnitude a, on the rate of increase dcr/dt, and
on its  peak values, as well as on the duration of the
   In a more general form
        Sj(t) is the percentage of the substance enter-
             ing the organism  in  unit time  (or of
             radiation  irradiating  the  organism)
             from  the medium including  the  geo-
             metric factor);
        rm   is  the percentage of deposition, of im-
             mobilization in critical organs;
        xm   is  the effect of the biological effect on
             any organ (on the  organism as a whole)
             from the unit of immobilized substance
             (transmitted energy).
   It is obvious that <7j8j(t)T is the quantity of  the
 substance in a critical organ (organs),  or the quantity
 of radiation interacting with the organ as a function
 of time, and entering from medium j.
   It should be pointed out that the magnitude < de-
 pends on the condition of the  organism. The  latter
 is determined by a great many external  effects, and
 undoubtedly by previous history (by  the unhealthy,
 or weakened,  condition  of the organism)  as well.
 This condition  should be determined  directly, or in-
 directly (by measuring the factors that influence the
 state of  the physical  and physicogeographical data,
 living conditions, and state of health), and should be
 introduced into the formula (the variable  *)  used
 to characterize the condition  of the organism, or
 population, or  more correctly its deviation from the
 norm,  attributable to  the influence of  external condi-
 tions,  and including  some  distribution  of the sus-
 ceptibility of individual organisms in the  given  popu-
   Under normal,  ordinary,  conditions,  the magni-
 tude *m can be taken as equal to unity (on the as-
 sumption of equal  sensitivity of all organisms  in the
 given population);
    (6) M is the effect of the interaction  (the mutual
 effect factor (of two factors, i, k (ingredients),  acting
 on  the given organism;
  The simultaneous effect must  be estimated  when
several factors are acting (generally speaking, for all
factors, including um) .
  The < dependence  is nonlinear, as a rule. The
function can have dimensions (especially in the case
of large doses, in the  case of the destruction of the
organism, of the onset in the organism of irreversible
changes), possibly even in  the  case  of very  small
doses (when the effect has a clearly expressed thresh-
old). However, we are convinced that the effects of
the action have  no threshold (accumulation of data
for small doses).  This is  important for  summing
effects from different ingredients;
   (7) Xim,n is the result of the intensification (or
weakening)  of the effect  on the  given population,
m,  taking  into  consideration the  effect of the dif-
ferent factors on several (n) populations simultane-
ously. The result of the complex effect may be writ-
ten as  £m  where  £m  is  a complex function  of the
values of £m and n.
   Thus, the result of the summed biological  effect
At is
j   1  i

   It is desirable, in order to sum the biological effect
 of heterogeneous effects, to express the magnitude
 (mm  in  units  of  permissible  «mjn(p), or  critical
 tmju(cr) values.  In other words,  in  terms of their
 relative values with  respect  to the  permissible  or
 critical effects for each type of effect,  or  ingredient
 (probably in «.P units  if c^cp and ccr, if ccr^e>cp).
   If the exact distribution, Nm, is unknown, the area
 of  distribution, S(t), can  be used conditionally.
 Incidentally,  this factor  can  have a value,  even if
 Nm is known (it may be useful here to  introduce the
 probability function  for  the potential  "encounter"
 between the organism and the polluting impurity).
   As already noted, what we have to know in order
 to resolve the question  of  the  permissibility of the
 load on the system under examination,  is the relative
 value of the  biological  (ecological) effect, not  its
 absolute magnitude;  that is,  its  relation to  some
 permissible, or critical value. There  are several ap-
 proaches in the case of a comparison  such  as  this:
 each  magnitude  tmjij can be  compared  to a pre-
 viously processed value of emj«(p) or tmju(cr), which
 are magnitudes for use in establishing  the values of
 the maximum permissible concentration (MFC) of
 ingredients for each  organism and factor, or of the
 maximum  permissible intake  (MPI)  (of  the  in-
 gredient), if it is a question of the integral magnitude
 (mm (t)dt  in the case of a  permissible load, or of
 values dangerous, or  fatal, to the particular organism

 (population)  in  the case of a comparison with the
 critical magnitude, ««.
   It is obvious that exceeding e« for this population
 is absolutely unacceptable if we are talking about an
 individual population, but  this assertion is not ob-
 vious  for an individual population  when  cm(cr) is
 exceeded for the system as a whole.
   This is followed by summing these relative values,
 using  Eq. (7) (and taking Nm(R)  into considera-
   The result  is the obtaining of  AP and ACT  (per-
 missible and critical) values, developed for a specific,
 concrete, natural  object,  or system, that take into
 consideration  all  the peculiarities  of the particular
 ecosystem  (system), as  well as  the  climatic and
 concrete  (at a given time) natural  conditions.
   It would appear to be obvious that when we  speak
 of  the stability  of biological systems  (or  of  other
 systems), we  have in  mind criteria for establishing
 the critical effect (that can lead to upsetting stability,
 and then to the conversion,  or  destruction, of the
   What we mean when  we  talk  about developing
 an  MFC,  or  MPI, for an  individual organism,  or
 population, is some definite  threshold, or initial path-
 ological (exceeding the limits of physiological norms)
 action, or  effect, which  usually is  reversible, and
 which certainly  does not upset the stability of the
 particular system.
  Consequently,  the formulation  of an  approach
 such  as this for  the entire  system  is extremely im-
 portant. At this point  it would appear that we can
 talk about MFC value for just a single, critical link.
 However, it is more important to  formulate an in-
 tegral  approach, even if no single value reaches the
 magnitude of  the  MFC, but the sum of the effects
 exceeds some magnitude, AP, for a system as a whole,
 acted  on  by a whole complex of effects simultane-
 ously.  This  approach, in our opinion, should be basic
 to a comprehensive analysis of the environment.
  The initial  approach here can be the use of the
 assumption of the lack of a  threshold in the accumu-
 lation  of data  (the occurrence of certain effects) and
 the determination of the magnitude fp,  by summing

 the relative values, 5
                   j i

  "A" will change by bounds, depending on whether
the  system is stable, or will  become unstable.
  This formula also is suitable for determining  dam-
age when the  effect is on  a  major system, when not
only the ecological damage is critical (but perhaps
not the major aspect,  but  so  too  is the possibility
of upsetting the stability (or approaching this critical
state)  of a major  physical  (geophysical)  system,
when estimating damage that can  result from  pos-
sible climatic changes, for example.
   Determination of the relative ecological damage,
Ar,  undoubtedly must be  made  successively,  with
possible approximation at first (selection of a limited
number of factors  for the effect of polluting in-
gredients,  and assumptions, where possible).  v=l,
   Systems analysis  approaches  are  necessary  when
solving similar problems.
The Scientific Justification for Monitoring
   In order to estimate the effect on a population,
community, or ecosystem  by the scheme cited, we
must have the values  of all the variables  contained
in this formula. There is no question  of the fact that
the solution to the  problem cannot  be  obtained  in
its entirety so we must proceed to simplify things by
selecting the most important factors of the effect, and
by  searching for the links that  are  critical,  or that
govern the state of the systems.
  Thus, regular observation must be made  (variables
Q, a, N, «, and others of the state of the  medium, its
future state must be predicted,  we must be  able  to
single out  changes  caused by anthropogenic action,
and we must be able to properly estimate this action,
by using the formulas cited above, for example. The
values of v, \, and of some of the others,  are found
through  research, and by setting up  special experi-
  Table 2  shows the scheme for observation, for the
production, and for  the estimate, of the  state of the
environment  (1). This system  is, in  essence, the
scientific justification for monitoring.  Let us  explain
the data in Table 2 in more detail.
   Observations (I)  of changes in the state of the
environment  include:
  A. 1.1. Observations of  the state  of the environ-
ment, and  of changes  in this state, characterized by
geophysical data, are made by means of successive
measurements of the corresponding parameters de-
termining the instantaneous state of the environment.
Such  observations  already are being  made by  a
number of  geophysical services.
  A. 1.2. Physicogeographic data,  including data on
the distribution of land and water, on the relief of
the land surface, on natural resources  (mineral,  land,
vegetable,  water,  fauna resources),  population, ur-
banization, and others, also are most important in-
formation to have on the state of the natural environ-
  A.2.  Observations of the state of the environment
(and  of changes in this state) characterized by geo-
chemical data, observations of  matter  and  energy
cycles in nature, observations of the  composition of
alien  impurities in  the biosphere (including radio-
active ones),  and observations  of different specific
types of pollution,  including  observation  of  noise,
thermal  pollution, and different types  of radiation
(the concepts of pollution in these latter  cases are
conditional, but are  generally accepted).

                                               Table  2
                                                                                      Estimate  of existing
                                                                                      and  predicted states
A. State of environment
                                A. 1. State  of the environment, characterized by
                                      geophysical and physicogeographic  data
                                A. 2. State  of the environment, characterized by
                                      geochemical data and data on the composi-
                                      tion and nature of pollution
                                      (AP in unique ob-
                                                      jects, that is,  for  A to  exceed some  permissible
                                                      value, AP, which was  determined above;
                                                         (3) moral damage is  not now subject  to estima-
                                                      tion as a practical matter, so will not be considered
                                                      here, or in what follows.
                                                         Let us  designate as E conventional systems  with
                                                      a reserve  (an "ecological"  reserve  for ecosystems)

          is the factual state of the system, the eco-
          logical load on the system; then

          A   ..A                   (9)
       At, is the state of degradation of the particular
       Ai is the  load attributable to the particular
   In our opinion,  C should depend on E;  that is,
the damage increases with approach to the boundary
of the ecological  reserve, C=E(Ao—Ar); that is, a
greater effort is required  (including that of  an eco-
nomic nature) to return the system to a normal state
from an unhealthy,  or changed, one.
   It is appropriate  to introduce the concept of mag-
nitude of damage per unit of production in order to
make  practical decisions
 1   D,
       Di is a product of the i"1 type, manufactured
          in the particular region, leading to damage
          Bi; the subscript i should be replaced by
                                                               the  subscript 2 when manufacturing  the
                                                               summed product to estimate the damage.
                                                       This formula is useful in making a decision as to
                                                     the  desirability (and  feasibility)  of manufacturing
                                                     the particular product as a function of the permissible
                                                     load, and of the relative ecological  (or  economic)
                                                       The economic effectiveness of the measures taken
                                                     to protect, or to restore, the quality of the environ-
                                                     ment may be estimated by comparing the assumed
                                                     expenditures, G, with the economic damage, B
       Defining "No  Significant Deterioration" of  Air  Quality
                                        Ralph A. Luken *

  The Clean Air Act of 1970 requires the Environ-
mental Protection Agency (EPA) to protect existing
levels of air quality in non-degraded  areas. Taken
literally, protection  means no change or deterioration
in the existing levels of air quality. Since no deterior-
ation  would severely constrain economic growth in
less developed areas of the United  States, the court
has interpreted protection to mean prevention of "no
significant  deterioration"  (NSD)  of  air  quality.1
However, the court did not define  significant in the
NSD ruling and has left the task to EPA.
  Since discussion  in a short paper of all the com-
plex issues associated with defining NSD is infeasible,
I have chosen to concentrate on (but  not limit  my-
self to) developing an economic definition of NSD.
The paper is divided into four major sections:
• Description of the Federal Law  relevant to NSD
• Economic definition of NSD
• Critiqueing on the basis of the economic definition
  the operational  definition  of  NSD preferred by
• The role of rigorous Environmental  Impact State-
  ments in  determining the significance  of  environ-
  mental deterioration


State Air Quality Implementation Plans
  Under the Clean Air Act of 1970, EPA is charged
with  establishing two  types of national  ambient air
quality standards:  the national primary  air quality
standard, which is that level  of air quality required
to protect public health,  and the national secondary
ambient air quality standard, which is that level of
air quality  required to  protect the public welfare
from any known  or anticipated adverse effects as-
sociated with the  presence of such air  pollution in
the ambient air (Table 1).
   EPA is also required to  protect  against significant
deterioration of air  quality even where  that air
quality exceeds the minimums prescribed in national
standards.  The statutory basis for  a NSD  policy in
the 1970 Act is found in Section  101, which states
that the purpose of the  Act is "to protect and en-
hance the quality of the Nation's air resources." To
allow deterioration of  existing  air quality  in  non-
degraded  areas is considered to be  antithetical to
achievement of the mandate to protect the quality of
the Nation's air resources.
                    Table  1
        Primary and Secondary Air Quality
            Standards for SO2 and TSP'

Annual . 24 hrs. 3 hrs.
80 365 	
Annual 24 hrs. 3 hrs.
75 260
60 150
  • There are also national ambient air quality standards for Carbon
Monoxide, Photochemical  Oxidants,  Hydrocarbons,  and  Nitrogen

   The  Act requires each State  to submit to EPA a
plan providing for the implementation, maintenance,
and enforcement of such ambient air quality stand-
ards within each of its air quality control  regions.
As a result of the Sierra Club  citizen suit, the plan
must now provide for the prevention  of significant
deterioration of  air quality  in clean areas. Each plan
must be approved by EPA before it becomes effec-
   In summary, the Clean Air Act of 1970 establishes
different  standards for  degraded and non-degraded
areas. For degraded areas, the  requirements  are for
achievement of  primary and secondary air  quality
standards. For non-degraded areas, the requirement
is for the protection of the existing level of air quality
even though the quality level exceeds the standard.

   Two heuristic economic definitions of NSD offer
 some insight into the problem of interpreting NSD.
 A general equilibrium definition would address the
 issue of whether national growth is over or under-
 constrained by a NSD policy. The definition in this
  •Chief, Water Programs Branch, Office of Planning and Evaluation. Environmental Protection Ai
  1 Sierra Club vs. Ruckelshaus, 344 F. Supplement 523 (D.D.C. 1972) affirmed, 4 ERC 1815 (
               [S!c' Circular 1972).

 case would be discussed in terms of a national linear
 programming model which  seeks to  minimize  the
 costs of production subject to restraints specified for
 environmental  standards and  demands  of the  do-
 mestic market. The  advantage of this approach is
 that  it recognizes that development is of national as
 well  as local concern  and fully accounts for the inter-
 dependencies among  several (if separate)  locations.
   A partial equilibrium definition would address the
 issue of whether a new source would be permitted in
 a specific location. The definition in  this case would
 be discussed in terms of marginal damage and  cost
 functions  associated with the residuals generated by
 a plant.  The advantage of this approach  is that it
 focuses  on the value of environmental damages  as
 well  as  the cost of control.  The partial  equilibrium
 definition is used in  this paper because of the  ad-
 vantages noted in the previous sentence as well as the
 fact  that the damage and cost functions can be  de-
 signed to  account for some national  as well as  local
 costs and benefits.
   Environmental  economists   have  given  some
 thought to the  "efficient"  level of discharge reduc-
 tion. For example, they have examined the residuals
 discharged by industrial, municipal, agricultural, etc.
 activities and have concluded that the  discharger must
 control his residual discharge up to the point where
 the additional costs of reduction begin to exceed  the
 benefits from further  curtailment of discharge.
   The "efficient" level  of discharge  reduction for a
 degraded area 3 is  diagrammed in the upper  half of
 Figure I.4 The amount  of residual discharge is  re-
 corded on the horizonal axis. In  the  absence of any
 control efforts by the  polluter, the maximum level of
 discharge equals B. Also, the corresponding  change
 in air quality is recorded on  the horizontal axis;  the
 highest level of environmental quality is 0. The cost
 of  controlling  residuals and  the dollar  value  of
 damages  associated  with increasing levels of  dis-
 charge  are  recorded  on  the  vertical  axis. Total
 damage  cost  (TDC)  is shown for various levels of
 discharge along the curve OC. The  curve has  zero
 slope (essentially no  marginal damages)  from O to
 A on the assumption  that there is no damage below
 the standard5; it increases at  an increasing rate from
 A to  C on the assumption that  the damages (for ex-
 ample, health effects) increase with  rising levels of
 discharge.6 Total abatement cost (TAC)  for a given
 level  of product output is shown for various levels of
 discharge reduction along curve  DB. The curve in-
 creases at an increasing rate because of the increas-
 ing marginal cost of controlling  residuals. The cost
 of control is D if all residuals are controlled. Curve
 DHC  is the total cost attributable to pollution and
 abatement, that is, it is the sum of TDC and TAC. It
 combines the cost of controlling residuals  with the
 damage cost associated with the remaining  residuals
 discharged. The efficient level of discharge reduction
 for a  given level of output is  discharge  level E,
 where the sum is a minimum.
   The efficient level of abatement may also be de-
 termined in the lower part of Figure 1 by comparing
 the marginal damage curve (MDC) and the marginal
 abatement  curve  (MAC).   The  efficient  level  of
 abatement is obtained when MDC = MAC as  it is
 at E. To the right of E, the  plant would be required
 by  a  society interested in efficient resource alloca-
 tion to curtail its residual discharge either by regula-
 tory actions  or by  the  imposition  of an  effluent
 charge. To  the left of E,  the plant would be  en-
 couraged by a society interested in efficient resource
 allocation  to  discharge  its  residuals  because  the
 damage to  the airshed is less than the cost of dis-
 charge reduction.  However,  the plant would be pre-
 vented from discharging its  residuals in the range
 from G to E because the standards are based on pro-
 tecting all populations  against  all  known adverse
 health  effects  rather than  a balancing of adverse
 health effects and  the cost of discharge reduction.
  The efficient level of abatement for a non-degraded
 area 7  is diagrammed in Figure 2. The units on  the
 axes are the  same. The shape of the TAC curve for
 a projected level of output is also the same. How-
 ever, the shape of the  TDC  curve  is fundamentally
 different as is the initial level of environmental qual-
 ity. The TDC reflects the assumption on the part of
 many environmentalists that the initial  deterioration
 or damage to a non-degraded area often results in a
 significant loss to  aesthetic amenities and, if it is an
ecologically  fragile  area, a   significant loss in the
regenerative  capacity  of the natural system.  The
shape of the curve suggests that the air quality stand-
ards are inadequate for protecting against all known
long-term adverse effects. Thus the TDC curve in
Figure 2 is a  composite of damages because it reflects
both aesthetic  and ecological effects  resulting  from
minute changes in ambient  concentrations  and the
health  and welfare effects normally  associated with
the TDC.
  "The diagram follows A. M. Freeman, III, R. H. Haven, and A. V. Kneese,  The Economics  of Environmental Policy (New York: Wiley

  4 A deteriorated or degraded area is defined as an airshed where the level of ambient air quality violates the national standards (Table 1).

  "The TDC is drawn in Figure 1 as a hockey stick (with a kink at A) to reflect  the fact that all populations in all areas must be given the same
level of protection against adverse effects.

  0 The TDC as depicted in Figure 1 is a short-run damage curve for one pollutant. A long-run damage curve which took Into  account cumulative
effects, or a damage curve for several pollutants would probably have a gradual slope from O to A in Figure 1.

  7 A non-degraded area is defined as an airshed where the initial level of ambient air quality does not violate the national standards.

                           G E
                •LEVEL OF AIR QUALITY

                         G     E
              LEVEL OF AIR QUALITY

                                       G     E
                        UNITS OF WASTE DISCHARGED
                                 •LEVEL OF AIR QUALITY
                     AESTHETIC EFFECTS
                       UNITS OF WASTE DISCHARGED
                              _EVEL OF AIR QUALITY

  The efficient level of abatement is determined  in
the lower part of Figure 2 by comparing the marginal
damage curve (MDC)  and the marginal abatement
curve (MAC). The section of the MDC curve be-
tween I and A reflects the aesthetic and fragile eco-
logical effects,  while the section between A and C
reflects the health and welfare effects. As long as the
initial  level of discharge  is to  the  left of F, the
efficient level of discharge  is near zero. However,  to
the right of discharge  level F, the efficient level  of
discharge would be in E  in  spite of the fact that
damages to a  non-degraded area would occur in the
range from F to G and national  standards would  be
violated in the range from  G to E.
  The MDC curve might shift from MDC to MDC'
in Figure 3a if it  reflected national as  well as local
concern  for non-degraded areas. Many urban resi-
dents in the U.S. have become increasingly interested
in  maintaining the  environmental quality  of non-
degraded areas for their future use, for their descend-
ants or just for the pleasure  of  knowing a non-de-
graded area is protected from environmental  deter-
ioration.8 MDC', which indicates that a higher value
is placed on  environmental damage,  can be seen  as
reflecting  both  local  and national concerns and
thus is a more accurate indicator  of societal  value.
Now as long as the initial  level of discharge is at F'
or  to the left of F', the efficient level  of abatement is
to  curtail residual discharge to near  zero. However,
to the right of discharge level  F'  the efficient level of
discharge  reduction would be  E  because  costs  of
control exceed demages in  the range from F' to E.
   Similarly, the MAC curve would shift if there were
opportunities foregone, such as electrical energy con-
sumption by individuals outside the region. The argu-
ment is that  cost curves ought to reflect both  onsite
and external  costs rather  than  only on-site cost. If
the users  of  electrical energy consumption outside
the region were  denied the  benefits of lower cost
electricity  generated  in  the region,  then  their loss
ought to be reflected in the MAC. MAC' in Figure
3b, which  indicates a higher cost of residual control,
sums both on-site and external  costs.  In this case,
there might not be a low level of discharge for which
MDC would exceed  MAC.  The efficient level  of
abatement would be E' rather than some low level of
discharge  for a non-degraded area as suggested in
Figure 2.
   The absence of certain types of  information limits
the operational usefulness  of an  economic definition.
The most  difficult problem is measuring the MDC
function or, more simply,  the value people place on
clean air. Moreover, estimation of MDC is more than
assigning values. For example, estimation of a MDC
requires three sequential steps:
  Step  1: construction of a transfer function which
          relates changes in residuals to changes in
          ambient conditions. Control of residuals
          can affect the  concentration of such pol-
          lutants  as  particulate matter and sulfur
  Step  2: estimation of  the  impact of changes in
          ambient concentrations on  human health
          and welfare. Linking changes in ambient
          concentrations to human health and wel-
          fare is the most difficult step in estimating
  Step  3: Identification  of the economic value of
          induced changes  in human health  and
  On first thought one  would think about  asking
people how  much they  value changes in clean air to
obtain information about Step  3. Since people are
likely to understate their preference for jointly-shared
social  programs,  several indirect  techniques  have
been devised to overcome this limitation. These tech-
niques measure losses  in  wages, residential property
values,  materials,  and  vegetation. While these tech-
niques have  provided some insight into the  benefits
of pollution control (damages avoided), they  usually
do  not  generate sufficient monetary information on
which to base a MDC function.
   Measuring the  cost  of control  is  sometimes as
difficult as measuring the  damages avoided. If several
plants are required to  control their residuals  simul-
taneously, then the change  in demand for pollution
control equipment may alter the price of this equip-
ment for all plants. If  a  plant controls its residuals
by  transferring them from water to the air, then the
control cost  must also  include the damage imposed
on the  other medium.  If there were an opportunity
cost associated with a  high level of abatement,  that
is, there are  benefits foregone by inhabitants in other
regions because the final output is restricted, then the
control cost  must reflect  the value of  these foregone
   Also, there are the  usual problems of separating
pollution control costs from process change costs and
determining  if the value  of the controlled pollutants
as a secondary product will offset the cost of control.
Information  about all  these conditions  is important
for a correct assessment  of costs.
   Another  difficulty is estimating the initial level of
environmental quality.  In many non-degraded areas
there are few if any monitoring stations for TSP and
SO;.. Vast numbers of measurements  would  be re-
quired to establish the baseline level of environmental
quality. Data variability is  still another  problem.
Normal variations in pollution concentration in clean
areas, especially TSP, exhibit  considerable variability.
  "There is considerable literature on the non-user values for environmental  quality (Krutilla, 1967). Weisbord (1964), for e:
                                                                                                has made a
                                                                                                  thly „'

                              I MDC
                           F      F'         E

                      UNITS OF WASTE DISCHARGED
                                 EVEL OF AIR QUALITY



                          F                E E'

                      UNITS OF WASTE DISCHARGED
                               •LEVEL OF AIR QUALITY

                           MARGINAL COSTS

For example, the 1968 TSP maximum concentration
at the Grand Canyon for participates was 126 /ig/m3,
and the annual average was 31 ^g/m3. In 1969, the
maximum concentration was 32 /tg/m3, and the an-
nual average was 12 ^g/m3. These differences are
caused by random variations due primarily to normal
meteorological factors.
  Even if essential data are unavailable, framing the
issue of NSD  as an economic problem is useful be-
cause it indicates the conditions under •which varying
degrees of deterioration of environmental quality are
efficient and are inefficient. Formulation of the issue
as depicted in  Figure  2  suggests that permissible
changes in air quality in non-degraded areas ought to
vary with the original level  of ambient quality and
the shape of the costs and damages curves. Essenti-
ally, permissible changes  will fall into three cate-
   • no change from current ambient concentration
     would  be  permitted under  conditions where
     there  is   exceptionable  ambient  quality  and
     MDC is  significantly greater  than MAC (Zone
     1 in  Figure 2).9
   • some change from current ambient concentra-
     tions would be  permitted  under  conditions
     where  there is high  ambient quality, but un-
     certainty about whether MDC is greater or less
     than MAC (Zone 2 in  Figure 2). As indicated
     above, there may be considerable uncertainty
     about  the  shape  and thus intersection of  the
     MDC  and MAC curves.
   • as much change from current ambient concen-
     tration as  necessary to accommodate new  de-
     velopment under conditions where there is good
     ambient quality and relative certainty that MAC
     is greater than MDC  (Zone 3 in Figure 2). The
     permissible increment  would  vary depending
     upon whether  national  standards dictated  the
     upper  limit (point H, Figure 2)  or whether an
     efficient  level  of abatement  dictates the upper
     limit (point E, Figure 2).
   In summary, a definition of NSD consistent with
 efficient resource allocation must meet two condi-
 tions. First, the definition must reflect both the costs
 and damages associated with  a change in residuals
 discharged. A  definition  based  on  either  costs or
 damages  alone  would not result (unless by chance)
 in an efficient level of residuals discharged. A defini-
 tion of NSD based  only on  a change in  ambient
 quality (damages avoided)  is inadequate because  it
 ignores the costs of achieving that change.  A defini-
 tion of NSD based only on a change in emission rates
 from a plant  is inadequate  because  it ignores the
 change in damages associated with that change. Both
changes in ambient conditions (damages) and emis-
sion rates (costs) are central to establishing a defini-
tion of NSD consistent with economic theory.
  Second,  the definition  must reflect  the  unique
characteristics of the situation. Both the original level
of ambient quality  and the shapes of the costs and
damages curves will  probably vary from  region to
region. The permissible, i.e. non-significant,  change
will vary within  a non-degraded area  and  among
non-degraded  areas.

  The operational  definition  of NSD of air quality
preferred by EPA  is partially but not entirely  con-
sistent with the economic  definition of NSD.  The
definition provides  that:
   • States divide their territory into three zones;
   • the Federal Government establish for each zone
     deterioration   changes  which  cannot be  ex-

Zone Designation

   A Zone I designation would be areas where little
if any change from  current  air  quality patterns is
permissible. States  would probably use Zone I desig-
nation where:
   • Development  of industry within the zone is in-
     consistent with desirable uses for the area.
   • The area should be protected from degradation
     due to pollution sources outside the area.
   • Development  of polluting sources would signifi-
     cantly degrade an area with  very clear air.
   A  Zone II designation would be relatively  unde-
veloped areas where some change is permissible. A
Zone II designation would be a recognition that the
point  of transformation  between Zone  I and  Zone
 III in a non-degraded area is often difficult to dis-
tinguish because of  the  uncertainty about the cost
 and damage  functions and the absence of physical
data. This designation would prevent  the arbitrary
 designation of an  area as either Zone I or III until
 sufficient data were available to make a  decision.
    A Zone II designation would be areas  where  major
 industrial  growth  is  desired and  where  increases in
 concentrations up to the national standards would be
 insignificant.  (Again, note that the national standard
 as a  limitation  is inconsistent  with the economic
 definition, which sets the point where MAC=MDC
 as a  limitation.) States probably would  use Zone III
 designations where:
    •  an  existing  urbanized  region has air  quality
      which does not violate secondary standards.
  • This definition appears to be more rettrictive than the statements of the Sierra Club on the issue of NSD. The Sierra Club recognized that
 NSD does not prevent all increases in pollution. "If the bed available  technological developments are utilized and if numerous pollution-produc-
 ing sources are not concentrated in one place, most industry can enter clean areas without causing significant deterioration." Ftderal
 July 16,  1973, p. 18987.

   •  counties are urbanizing.
   •  areas are designated for concentrated develop-

 Zone Changes
   The Federal Government has indicated permissible
 air quality changes for Zone I and II for SO2  and
 TSP  (Table  2).  (A permissible change for Zone III
 is not necessary because it is the difference between
 initial ambient quality and secondary standards.) The
 permissible  changes for Zone  II  were  calculated
 backwards from the impacts  on the ambient environ-
 ment in  an open terrain of an 850 MW power plant
 and a 200,000 bbls/day petroleum refinery with the
 application of best practicable  control technology.
 (See  Appendix A for more detail.) The permissible
 changes  for  Zone I were very small numbers, arbi-
 trarily chosen, which would allow little or no change
 from the initial ambient quality.
                     Table  2
      Permissible Increments for Zones I and II

Zone I
Zone II
Annual 24 hrs.
5 15
10 30
Source: Harbridge House, "The Impact of Proposed Non-degradation
Regulations on Economic Growth," EPA, BOA #68-01-1561, Novem-
ber, 1973, Volumes Mil. Also, U.S. Federal Register (July 16, 1973),
pp. 18990-18993.

   The permissible changes for Zone I and II are not
absolute limits on the potential changes  in ambient
concentrations, in that State government can alter the
final designation of a  given area if  the resulting air
quality  does not correspond to significant  degrada-
   The  area  classification definition is partially  but
not entirely consistent with the economic definition
for the  following reasons. First,  it incorporates the
idea that the permissible deterioration in  air quality
ought  to vary  within  a  non-degraded  area  and
among non-degraded  areas. It allows for variability
within a non-degraded area with the three zone clas-
sification which takes into account the initial ambient
concentration and the physical, biological, and  eco-
nomic development status of an area.
   It allows for variability among non-degraded areas
by permitting States to modify the level of  deterior-
ation given adequate consideration of costs and bene-
fits. Second,  the permissible  changes established by
EPA are based on the cost of control. The Federal
definition is based upon technology which has already
 been installed by industrial establishment  without
 undue financial hardships. In addition, an economic
 analysis of the impact of the Zone II requirements
 suggested that industrial growth would not be unduly
 restricted  in  upper New York State,  Dallas/Fort
 Worth area, and the Four Corners region.10
   The  definition  is inconsistent with the economic
 definition in that the operational definition was not
 based on a comparison of the benefits and costs as-
 sociated with  the zonal limitations. The zonal limita-
 tions incorporated only the first  step in benefit analy-
 sis,  i.e., relating  residuals discharged  to  changes in
 ambient concentrations. It did  not incorporate the
 effect of the  changes  in  ambient concentrations  on
 human  health and welfare and the economic value of
 the changes in human health and welfare. Thus, there
 is no information about the physical  and monetary
 damages associated with the permissable changes for
 Zone I  and II. Whether  they are of greater or less
 damages than the associated costs of control is still
 an unanswered question.
   In summary, the proposed operational definition
 is only  partially consistent with  the economic defini-
 tion of NSD.  The operational definition accounts for
 the  need  for variation in  permissible  air  quality
 changes in non-degraded areas  and  is based on the
 costs of controlling residuals. However, the permitted
 changes in air quality  for each zonal type  are not
 based on the  damages or the  absence  of damages
 associated  with  the permissible changes; this will
 restrict  the ability of the States  to balance costs and
 benefits to some extent in their zonal designation.


   As a practicable matter, estimation of a national
 MDC  function  associated  with  the  permissable
 changes is an  impossible empirical task. The data are
 not  uniformly and consistently  available.  However,
 Environmental Impact Statements (EIS), which are
 micro-evaluations  of environmental consequences of
 proposed actions, are a potential source of data about
 local damages. They potentially offer  data for  esti-
 mating the local MDC  associated with the residuals
generated by a new industrial source.
   The EIS, which was introduced  into the Federal
decision-making process by  the National Environ-
 mental Policy  Act of 1969, must cover five points: "
   Part  1—the environmental impact of the proposed
   Part  2—any adverse environmental effects which
   cannot be avoided should the proposal be imple-
  M Harbridge House, "The Impact of Proposed Non-Degradation Regulations on Economic Growth," EPA BOA #68-01-1361.
  11 The following material is based on a piper prepared by Neil Orion1, "The Environmental Impact Statement Process," Director, Regional Liai-
son Staff, EPA, Washington, D.C. February 1973.

  Part 3—alternatives to the  proposed action and
  the  results  of not  accomplishing  the  proposed
  Part 4—the relationship between local short-term
  uses of man's  environment  and the maintenance
  and enhancement of long-term productivity, and
  Part 5—any irreversible and irretrievable commit-
  ments of resources which would be involved in the
  proposed action should it be implemented.
  The proposed actions under  Part I are limited pri-
marily to  three types of action—licensing activities,
funding activities, and activities directly and wholly
undertaken by the Federal Government.  More re-
cently the courts have ruled that reconstruction of a
segment of highway was a Federal action because,
even though that segment was  not Federally-funded,
the overall project  was Federally-funded.
  The environmental effects under Part 2  have been
defined very  comprehensively  in the Federal guide-
lines. The environment is not  to  be considered just
in terms of air or water pollution or physical changes
in the land. The environment also includes the social
environment.  The  environmental effects must take
into account the adverse effects in excess of those
created by existing uses in an  area. Thus  the effects
in a non-degraded area could be recorded as being
very different than the effects of a similar ambient
change in a degraded area. Also, environmental  ef-
fects must take into account the cumulative harm to
an  environment.
   Consideration of alternatives under Part 3, as this
process has come  to  be defined  by Federal guide-
lines,  could contribute significantly to estimating a
   "Agencies must indicate in their procedures that
   all reasonable alternatives and their environmental
   impacts are to be discussed, including those not
   within  the  authority of the agency. Examples of
   specific types  of alternatives that should be con-
   sidered in connection with specific kinds of actions
   should  be  given where possible. Such examples
   should  include, where relevant:
   (1) the alternative of taking no action;
   (2) alternatives requiring actions of a significantly
       different  nature which  would provide similar
       benefits  with different  environmental impacts
       (e.g.  a fossil fuel vs. a nuclear power plant);
   (3) alternatives related to different designs or de-
       tails  of  the proposed action, which  would
       present different environmental impacts (e.g.
       pollution  control  equipment on  a nuclear
   In each case, the analysis  of  alternatives should
   be sufficiently detailed and  rigorous to permit in-
   dependent  and comparative  evaluation  of  the
  benefits, costs and environmental risks of the pro-
  posed action and each alternative." 12
Thus, the process of analyzing alternatives has the
potential for generating not only physical data  about
a project, but also data about the value associated
with a change in the environment.
  However, the greatest potential for providing in-
formation about how the public values environmen-
tal damages reported in an EIS is in the public com-
ment period,  assuming that there is well-prepared
EIS. For the first time in many instances, concerned
citizens  will have the technical information on the
environmental  consequences from the introduction
of a new source  of residuals and an opportunity to
state formally  their opinion. Draft  EIS's  must  be
available to interested public and  private groups for
comments  and any substantive comments  must  be
included in the final  EIS. This process allows  them
to record their valuation  of the environmental im-
  Since public and private groups in all parts  of the
U.S.  can comment on EIS's,  the comment process
has  the potential  for soliciting local, State, regional
and national  concerns. If there  are numerous ex-
pressions of non-local  concern, they would provide
at a minimum an indication that significant  values
are  being lost and at a maximum a basis for a shift
in the MDC depicted in  Figure  3 a.  The new MDC
would be a more accurate indicator of value because
it would be a summation of the value of all interested
parties  for a jointly shared good.
   This type of information for estimating MDC will
be  generated  for  more projects in  future years be-
cause there is a growing trend in  the States to adopt
requirements  for EIS's  like those  of the Federal
Government.  Fifteen  States and Puerto  Rico now
require impact statements for a wide range of activi-
ties (sometimes including local and private projects)
significantly affecting the quality of the environment,
and several others apply the process to limited classes
of  projects. At least twenty other States have such
requirements  under consideration.13
   In concluding this section, I do not want to leave
an  overly  optimistic  impression about  how  much
data EIS's will provide  for estimating MDC. Esti-
mation of a total  damage cost  curve, from which the
 MDC  is derived, requires physical  and  economic
data over a range of abatement levels. Physical and
economic data over  such a range  are very difficult
if not impossible to obtain. However, EIS's do have
 the  potential  for generating  a  few  physical  data
 points and a proxy for the value of the environmental
 damages. As limited as this information might be, it
 would  be more information than is usually available
  « U.S. Council on Environmental Quality, "Guidelines on the Preparation of Environmental Impact Statements," 40 CFR 15.8A4.

  is A more ««ns]j' dff£LT,tion of State  programs Is available in Thaddeus Trzyna, "Environmental Impact Requirements in the States," EPA
 Contract #68-01-l»l» U»74).

 for  determining whether  a new source should  be
 permitted in an area.

   The  proposed economic definition of "no signifi-
 cant deterioration" suggests that the permissible, that
 is non-significant,  changes  in  ambient  air  quality
 vary  within and  among  non-degraded areas. The
 size of the permissible change  would depend upon
 the initial level of ambient quality and the costs and
 damages functions.
   The  operational definition of NSD  preferred  by
 EPA would require States to classify their territory
 into three  zones  and  the Federal Government  to
 specify permissible changes  in each zone. The area
 classification definition is partially consistent  with
 the economic definition.  It  is consistent because  it
 incorporates the idea that the  level of permissible
 changes ought to vary within and among different
 areas and it is based on the  cost of control. It is not
 entirely consistent because it is  based  on a  limited
 comparison of the benefits and costs associated with
 the zonal  limitations.
   As  a practical matter, estimation of a national
 damage function  associated with  the  permissible
 changes is an impossible  empirical task. One viable
 option, however, is  to  estimate the local  MDC re-
 sulting  from the residuals  generated by a new in-
 dustrial source. Environmental Impact  Statements,
 which are micro-evaluations of environmental  con-
 sequences,  are a  potential source of data for this

  Anderson,  F., NEPA in the  Courts  (Baltimore: The
Johns Hopkins Press, 1973).
  Freeman, A. M. Ill, Haveman,  R. H. and Kneese, A. V.,
The  Economics of Environmental  Policy  (New York:
Wiley, 1973).
  Harbridge  House,   "The  Impact  of  Proposed Non-
Degradation  Regulations  on Economic  Growth," EPA,
BOA  #68-01-1561, November  1973, Volumes I-III.
  Krutilla, J.,  "Conservation Reconsidered," American
Economic Review, 57 (December 1967).
  Orloff, N.,  "The Environmental Impact Statement Proc-
ess," speech, February 1973.
  Sierra Club vs.  Ruckelshaus,  344  F.  Supplement 423
(D.D.C. 1972) affirmed, 4 ERC 1815 (D.C. Circular 1972).
  Trzyna, T., "Environmental Impact  Requirements in the
States," EPA  Contract  #68-01-1818 (1974).
  U.S.  Department of  the Interior, "Navajo Project En-
vironmental Statement," September 1971, draft.
  	 "Navajo Project  Environmental
Statement," February  1972,  final, Appendix I  (Review
  	 Statement on Anti-Degradation,
September 1968.
  U.S. Federal Register (July 16, 1973), p. 18987.
  Weisbrod, B., "Collective Consumption  Services of Indi-
vidual Consumption Goods," Quarterly Journal of Econom-
ics, 78 (August 1964).

  Table A-l shows the impact of five point sources
on four Air Quality Control Regions. Concentrations
were computed after the application of Best  Prac-
ticable  Control  Technology.  High  concentrations
caused  by the  power  plant  are due to several  as-
sumptions. These assumptions  called  for an 850
                                              Table  A-l
                                Predicted Impact ( g/m3) of Point Socrces
                                            in Four ACQR's*
Source Type
Coke Oven
Cement Plant
Power Plant
Open Terrain
24- An-
hr. nual
1.6 0.3
110 23
95** 13
24- An-
hr. nual
0.7 0.6
0.7 0.1
0.6 ..
0.1 ..
Valley Terrain
24- An-
hr. nual
2.4 0.3
122 26
437** 16
24- An-
hr. nual
2.1 0.6
0.5 0.1
0.8 ..
0.1 ..
Open Terrain
24- An-
hr. nual
0.6 0.2
100 16
89** 8.7
24- An-
hr. nual
0.8 0.6
0.7 0.1
0.6 ..
0.1 ..
Valley Terrain
24- An-
hr. nual
2.4 0.2
122 26
447** 9.9
0.1 ..
24- An-
hr. nual
2.1 0.7
0.4 0.1
0.8 ..
0.1 ,.
•AQCR: Air Quality Control Region
••High concentrations due to short stack (122 meters) and targe size (850MW)
NOTE: The figures in this table represent those maximum ground level concentrations estimated to accompany the Ben Ltvil of Technology.

MW plant, burning 2% sclfur coal with a stack of
122 meters. If the stack height had been greater, the
contribution would have been less.
  Table  A-2 shows  SO2  and TSP  concentrations
resulting from 14 power plants in the midwest United
States. Twenty-four hour results are based  on ob-
served stability wind readings obtained from meteor-
ological observations at nearby airports for a period
of 1 year. Existing  output  of SO2  and TSP were
modified to  reflect  compliance  with  New  Source
Performance  Standards  (NSPS).
  Table A-3  shows   1-hour  SO2 concentrations
around  five coal-fired power plants. Column 4 shows
measured SO2 and column 5  modified SO2 concen-
trations which are likely if the plants were in com-
pliance  with  NSPS.
                                             Table A-2
                       Maximum 24-Hour Concentrations for Selected Power Plants
                                 Using Observed Stability Wind Roses1"
Stack Gas
Temp. (°F)
Height (m)
SO (ug/ms)
SO (Mg/m')
TSP (ug/m11)

•Existing coal burning plants, maximum estimated ground level concentrations assumed to meet NSPS by burning 0.7% sulfur coal.

                                              Table  A-3
                         Impact of Selected Power Plants on 1-Hour Air Quality'1'
Fuel Mtasured
Source Description
1000 MW Plant
Flat Terrain
2-450 ft. Stacks
1500 MW Plant
2-265 ft. Stacks
10-250 ft. Stacks
120 MW Plant
2-265 Ft. Stacks
455 MW Plant
Rolling Terrain
3-400 ft. Stacks
1700 MW Plant
Flat Terrain
2-600 ft. Stacks
1-800 ft. Stack
2.2% S
3.8% S
Assumed 1-hr. SO
0.7 %S 1048 ug/m'
0.7%S 2358 u8/m'
0.7%S 733 ug/m'
0.7 %S 825 ug/m'
0.7%S 2600 ug/m'
Modified Distance to Max
3-hr. SO Concentration (km)
273 u8/m'
319 u8/m'
273 ug/m'
150.8 ug/m'
304 ug/m'
Maximum estimated average ground level concentrations

  Determining  Acceptable  Levels  of Health  and  Environmental
                                         Fred H.Abel*
  This conference is concerned with the process of
developing  comprehensive  environmental  quality
management plans. These plans include a determina-
tion of the maximum pollutant environmental load-
ing (MPEL), i.e., a determination of the maximum
emissions  allowed in any part of the region at any
point  in time.  The  determination of the MPEL, in
turn, depends upon the level and kind of  economic
activity allowed, the cost society  is willing  to pay to
obtain the desired  level of environmental quality,
the level  of damages  from pollutants society  will
accept, the distribution of costs  (who pays costs)
and the distribution of benefits (who receives bene-
   Societies must realize that  the determination of
MPEL does depend upon these factors and so these
factors should be explicitly considered in the decision
processes. In deciding  to control  pollution, societies
have decided to trade off some economic growth, less
expensive products, or better quality products for a
better  quality  environment.  This process of  con-
sidering and then trading off the advantages of ad-
ditional pollution control  against the cost of ad-
ditional control  is called  cost-benefit or  trade-off
   Whenever a  decision is made, there  is,  either im-
plicitly or explicitly, consideration given to the ad-
verse effects (costs) and desirable effects  (benefits)
that will  result from the decision. Our objective  as
scientists  is to make these trade-off considerations  as
explicit and as  full  of knowledge as possible.
   The presentation will proceed as follows. The con-
cept of damage functions is developed with attention
being given to  the  kinds of environmental pollution
costs and health damages. Problems of quantifying
damage functions and in turn valuing them in eco-
nomic terms are discussed. The concepts of  social
costs of  control and  cost functions are developed.
The principle of comparing costs to benefits is dem-
onstrated in terms  of economically valued functions.
This  process of balancing costs with benefits is ex-
tended to include complications  arising when  many
costs and  benefits  cannot be valued  in  economic
terms. Finally, the  status of cost-benefits as a cri-
terion for determining acceptable levels of pollution
in the United States is presented.

   There are many adverse effects  of  emitting pol-
lution into the environment. Most societies are con-
corned with  the health and environmental damages
from pollution.
   The number and kind  of  effects society  suffers
from pollution are a function of the  level of pollution
and the exposure of people to it. Curve A in Figure
 1 shows the  number of effects increases as the level
-of pollution  increases. The effect function measures
the  rate of incidence of a specific  effect,  such as a
premature death,  an asthma  attack,  wildlife  de-
stroyed, crops destroyed, etc. Similar functions would
be determined for  each  kind of effect.
   Curve A in Figure  1  is  a hypothetical  curve: the
actual  curve could be quite different  for each pol-
 lutant and each kind of effect. If a pollutant causes
few effects below a given level (threshold)  but many
effects above  the  level, then the  damage function
 would look more like  Curve B in Figure  1. The ac-
 ceptable level of pollution depends upon  the exact
 slope of  the damage  function and in turn,  on the
 location of point PI, if there is a threshold. In prac-
 tice, we may have a function like A  but, because only
 the part of the function above point P3 has been de-
 termined due to the difficulty of monitoring and de-
 termining  effects  at  low  levels of pollution, point
 P3  may be misinterpreted as a threshold.
   The functions A and B in Figure 1 imply  a very
 precise relationship between  the level of exposure
 and the number of effects. Actually, a  statistical pro-
 cedure is  needed to estimate these curves. Thus, a
 point on  a curve, like point Z, is only  the average or
 the expected number of effects. There  is a frequency
 distribution  of number of  effects from  exposure level
 P2 around the point Z as indicated by the curve H.
 There are two reasons for the frequency distribution
  •Economic Analysis Branch, Washington Environmental Research Center, U.S. Environmental Protection Agency

 H. One is the natural variation in individuals' or
 environmental response to pollution exposure  P2.
 Second, there are errors in the data used to quantify
 the relationship. The  variance  becomes  relatively
 large at low levels of exposure, primarily because of
 the data problem.
   If  the variance of  the function A is known, then
 confidence  limits can be estimated  and confidence
 bounds like A' and A" can be displayed as  in Figure
 1.  The  existence of variance around  the damage
 function makes the process of determining the ac-
 ceptable level more complex and less certain.
   The  damage function is  based on exposure  and
 not on emissions. This has a significant impact on
 regional environmental  management  because  ex-
 posure  can be reduced  in several ways. One way is
 to  reduce  the level of pollutants emitted  into  the
 environment. A second way is to shift  the location
 of either the receptors (the people) or the  polluters,
 such  that exposure  is reduced. A third way is to re-
 duce  exposure by removing the pollutants  from the
 environment at the receptor, i.e.,  air conditioning
 buildings to avoid air pollutants, or pretreating water
 to remove pollutants.

   Pollution imposes burdens (pollution costs) upon
society by causing deterioration in materials and liv-
ing things (damages),  by causing concern and  dis-
satisfaction with the  quality  of the  environment
(psychic costs), and  by causing  extra  expense
(avoidance costs) to reduce the potential damage
and psychic costs.

Damage Costs
   Included in  this category are those  effects  on
physical things,  including  human health,  that result
from  exposure  to pollutants. Effects  on materials,
buildings,  vegetation and direct expenses involved
with adverse health effects are examples. These dam-
ages result in decreased value of an item, decreased
useful life of a structure  or item and direct  out-of-
pocket costs associated  with the damage (i.e., doctor
or  medicine  costs).  Health damages will be  dis-
cussed in some detail below.
   In  estimating damage  from pollution, dose-re-
sponse relationships  that show how  much more
                                                  Pi           P2

                                    LEVEL OF POLLUTION

                               FIGURE 1.  DAMAGE FUNCTION

quickly things deteriorate and become nonfunctional
as a result  of being exposed to different levels  of
pollution  are  needed. Dose-response  relationships
will  allow estimates of the extra costs to industry
and to society for replacing equipment and buildings
more frequently. In the United States, estimates have
been made  of the  level  of materials  damage from
several air pollutants. These  estimates are shown in
Table  1. (Blank cells indicate that estimates are not
available.) This  was done by determining the levels
of exposures and  quantities  of materials exposed
under the current situation and estimating how much
less  deterioration there would be if pollution levels
were reduced to meet the  standards.  The materials
damage estimates  are for  unpainted  metals,  paint,
rubber, and textiles. It was determined that the eco-
nomic values of damages  to many other materials
such as concrete, glass, stone, and leather are very
small.  Estimates of  damage  to  vegetation were de-
termined  in  a similar way. That is,  estimates were
obtained of: (a) how the yield  of agricultural crops
or the growth of horticultural plants  are related to
levels  of  pollution, (b) the  total acreages of these
commodities exposed to pollution and (c) the value
of the  damage. The damage value was assumed to be
the loss in revenue to producers because of reduced
Psychic Costs

   This category includes the value of dissatisfaction
and reduced quality of life that results because pol-
lution exists. It  includes  the value of the  dissatis-
faction that  results because  (a)  pollution interferes
with enjoying the natural environment, and with vis-
ibiilty of scenic  vistas, (b)  populations of wildlife
and natural  vegetation have  been reduced, (c) pol-
lution causes discolored vegetation, dirty  buildings
and littered  waterways and (d) people  know the
environment  is  being  violated  by  indiscriminant
dumping of wastes. It includes the value people as-
sociate  with maintaining  as  many natural or  high
quality  areas as  possible because this  gives  them
more choices for  recreation.  It  includes the  value
people place on leaving future generations a better
quality environment, and it includes the value of fear
that people have for the welfare  of the environment
and the  welfare of mankind. People are willing to
live with some risk. At some  point, they  will be will-
ing to give up  some goods  and services to reduce
risk. Determining  this level  of acceptable  risk is a
major need in environmental  decision making.
   Estimating psychic costs is very difficult. It is  al-
most impossible to obtain a  dose-response relation-
ship because the response is primarily  in  the  state
of mind of a person. A dose-response relationship is
obtained either by observing the behavior of people
as  changes in environmental loadings occur, or get-
ting them  to express their changed state of mind  in
some terms that can be quantified.
   For example, if paniculate matter is  emitted into
the air,  it can  cause soiling  of buildings and prop-
erty; and  if people find  this reduction  in aesthetic
quality of  the  buildings  objectionable,  they would
spend  additional energy, time and resources in clean-
ing up the properties. The level of effort  expended
would be  a measure of the  damage or social  costs
from particulate matter emissions. Another method
of  estimating psychic costs associated with  aesthetics
in  urban areas  is concerned  with the value of prop-
erty or the level of rent. In either case,  the value of
the property or the value  of  the rent will be reduced
if people perceive  an  aesthetically less  pleasing en-
vironment. The  aesthetic values in Table 1  were
derived in this manner.
   The extra cost of traveling to alternative  recre-
ation sites would be an estimate of the  value of  the
psychic costs of pollution. The value of water recre-
ation costs in Table 1  were  derived  in  this manner.
                           Table 1.  United States Annual Pollution Costs, 1970 '
                                              (billions of dollars)

Aesthetics and Soiling '
Human Health
Water Supply




Best Range

0.9 0.5-1.3
0.2 0.1-0.3



0.3 -1.0
2.5 -2.7
0.6 -1.0

1.2 -2.2

  1 Blank cells indicate that values have not been estimated.
  * Based on property value changes.
 Source: Waddell, Thomas E., "The Economic Damages of Air Pollution" unpublished report, National Environmental Research Center, Environ-
 mental Protection Agency, Research Triangle Park, N.C., February  1974. Tihansky, Dennis P., and Richard Walsh, "A Status Report on the Na-
 tional Benefits of Water Pollution Control" Washington Environmental Research Center,  Environmental Protection Agency, Washington, D.C.,
 November 1973.

 People's fear of environmental catastrophies or their
 dissatisfaction with the knowledge that the environ-
 ment  is not being  preserved in the best possible
 quality  is  determined by  a  survey which  would
 ask them  to make tradeoffs  among many different
 things they want. For example,  would they rather
 have cheaper electricity or  more  miles of pollution-
 free water? In practice, these  survey techniques have
 only recently been tried and are only of limited suc-
   Even  though  estimating the   psychic  costs  as-
 sociated with pollution may  be  very difficult, this
 does not mean that it is unimportant. In fact,  many
 of  the environmental goals  and many of the objec-
 tives of a comprehensive environmental management
 plan are derived  from the fact  that people desire
 these goals that affect their state  of mind and  their
 ability to enjoy the world.
 Avoidance Costs

   Avoidance costs, the third kind of costs  resulting
 from pollution, are out-of-pocket  expenditures  in-
 curred to avoid damage and/or reduce psychic costs.
   Examples of this are people incurring extra  ex-
 pense to paint metals so that they will not deteriorate,
 people  moving from  a polluted location to an un-
 polluted one to avoid  getting  sick, people  moving
 from a polluted environment to a non-polluted one
 to enjoy the increased aesthetics. It  includes the  de-
 cisions  to  stop growing crops  that  are  affected by
 pollution and growing otherwise less profitable crops
 that are resistant to the pollution. It includes people
 incurring costs by pretreating water or  air  so  that
 the  pollutants  are  removed  before  the  medium is
 consumed. Many  of  these  costs can be estimated
 if the share of  the total expense that is incurred be-
 cause  of pollution can be determined.  Only  that
 share should be counted as pollution  avoidance costs.

   Most societies are very concerned with the effects
of pollution on the health of its citizens. This effect
deserves and has received a good deal of attention.
There are five ways that  health effects impact upon
the citizen, his family and community.
   1.  Increased doctor, medicine and hospital costs
   2.  Value of loss from  premature deaths
   3.  Value of time lost from work or other activity
   4.  Reduced productivity  of work if performed
   5.  Value of suffering from sub-clinical  effects
   Some or all of the above costs would apply to any
given  health  effect.  Some of these components of
damages can be  estimated  in economic  terms,  al-
though it is difficult. The  biggest problem  with esti-
 mating the value of medical costs, lost activity days
 and reduced  productivity is determining the share
 of the total observed effect that is attributable to  the
 pollutant when other factors also affect these costs.
   The problem of placing an economic value on pre-
 mature death has often been described as putting a
 value on life, when it is the  length of life that is
 affected. Determining  a value for reduced length of
 life is very difficult, particularly  if age, occupation,
 health  status,  and  family status obtain  different
 values for individuals.  There is no way to determine
 the correct or true value of an  additional day of life,
 and none will be proposed here. However, it is clear
 that the value cannot  be  infinity, which is the value
 people assign if they insist that  a life should be saved
 (actually increase length  of life)  regardless  of costs.
 It is also clear that the  value is not zero, which would
 imply that nothing would be done to extend length
 of life, even if it  were  very cheap or free. Given  the
 importance societies attach to premature deaths and
 the difficulty of placing a value on them, it is often
 necessary to present the number of days lost because
 of premature deaths to the decision maker  and let
 him make the tradeoff.
  Determining the value of suffering is also difficult.
 In principle,  people are willing to put up with some
 suffering rather than give  up goods and services they
 enjoy. At some point,  however, they would be will-
 ing to give up some goods and  services in return  for
 lower levels  of  suffering. The value of goods  and
 services people would  give  up (their  willingness to
 pay)  for  a given reduction in pollution exposure to
 reduce suffering would be the  correct value to use.
 In the absence of good estimates of these values, the
 total number of hours of suffering as a function of
pollution exposure should be presented as the dam-
 age function.
  Because of the difficulty of putting economic values
 on  premature death and  suffering, the health dam-
 ages from pollution can be presented as three dam-
 age functions: one showing the number of days lost
 because of premature  deaths, one showing hours of
 suffering,  and the third showing the economic value
of all  other health impacts. One health damage func-
tion that has been estimated is shown  in Figure 2.
The damage  function  shows  the  percentage of a
 normal, healthy population between ages 10  and 65
experiencing  some  ill  effects  as  oxidant levels  in-
crease. The upper and lower  curves are the 95%
confidence bounds.
  Also, functions of mortality rate versus paniculate,
sulfate,  and socioeconomic variables were estimated
with regression analysis,  and  a significant, positive
linear  function  for  each pollutant  was  obtained
 [Lave, L. B.  and E.  P.  Seskin.  Air Pollution  and
Human Health.  Science  769(3947) :723-733, Au-
gust 21, 1970].  The number of  persons to  die per
 100,000 population increased 0.041 per microgram

      100  r-








                0.2     0.4    0.6    0.8    1.0    1.2    1.4     1.6     1.8     2.0     2.2     2.4    2.6

                                           OXIDANTS, PARTS PER MILLION

per cubic  meter increase  of average annual  par-
ticulate reading, and  0.071  each microgram  per
cubic meter increase in sulfate level. A 95% confi-
dence bound for the particulate coefficient is 0.009
to 0.073, and for sulfate coefficient is 0.027 to 0.115.
These rates are reliable only for pollution levels near
the mean of 4.7 micrograms sulfates and  120 micro-
grams particulates per cubic meter and with the  level
of other variables held constant at their  means. In-
cluding both pollutants in the analysis is  superior to
estimating the effects of each  and ignoring the  level
of the other.  If synergism  exists, it can be incor-
porated by the  inclusion  of interaction terms. The
results would  then indicate that the effect of an in-
crease in  one pollutant depends upon the  level of
the other.  Thus, the decision about the acceptable
level for both pollutants would have to be made at
the same time.
   Information presented to the decision maker when
synergism is present must be different than that dis-
cussed above.  For example, instead of a single dam-
age function for a pollutant, a set of damage func-
                                              tions must be presented. Each function in the  set
                                              would  assume a  different level for the synergistic
                                                Health  effects  damages of  water pollution have
                                              also been  determined. This was done by determining
                                              the number of illness outbreaks in the U.S. and  de-
                                              termining  the  share  of those  attributable to water
                                              pollution.  A value per illness  was then  used to  ob-
                                              tain the estimate  of  $0.7 billion per year as shown
                                              in Table  1. These  estimates  are crude  and dated.
                                              It is expected that more accurate and comprehensive
                                              estimates  would be  several times  larger.
                                              V. COST FUNCTIONS

                                                When a decision is made to control pollution by
                                              reducing the  level of current emissions, by prevent-
                                              ing the increase  of emissions or by relocating the
                                              source of the emissions or receptors,  it imposes costs
                                              on  society.  There  are  costs  of  administering and
                                              enforcing the decision,  costs  to  plants for add-on

 equipment, process changes,  or changed input mix,
 as well as costs to society of poor quality products,
 increased  unemployment  and  reduced  economic
   These costs can be quantified in economic terms,
 except for the costs (burdens) to society from de-
 creased employment and reduced economic  growth.
 Thus, it is necessary to  supply the decision maker
 with information  on three kinds of adverse effects:
 employment,  economic growth and economic costs.
   The costs of obtaining a given level  of pollution
 emission  control  can vary substantially, depending
 upon  the implementation strategy used. If the time
 period for obtaining control is lengthened, the costs
 would be  reduced as plants have time  to phase in
 new equipment and because new, more efficient tech-
 nology may be developed.  If  control applies to all
 plants, only large  plants,  only new plants, etc., costs
 will vary widely. Thus, cost analysis requires  that the
 implementation strategy  be pre-determined, several
 alternatives be studied or  the least-cost  (econom-
 ically  most efficient) method  be determined. In the
 least-cost case, the required level of control is based
 on the cost of control. The optimum solution has the
 cost of an additional unit  of  control equal for all
 plants. In all cases, it will be necessary to determine
 the  number, distribution  and kinds of sources,  the
 control options and  their associated  costs available
 to each source, and the  probability that the  control
 costs would be so high as to force the closing of the
   Studies have shown that the least-cost  strategy has
 significantly lower costs  than  strategies  designed to
 impact each source uniformly. A  least-cost solution
 is obtained by  linear programming, where each kind
 of  source  is  considered, available control  options
 are included as activities  and total emissions  are the
 constraints. The solution  specifies the control bption
 and emission level for each kind of source such that
 total costs  are  a minimum. Alternative solutions are
 obtained as the  constraints  (total  emissions) are
 varied and a least-cost cost function is derived.
   Cost functions  have been estimated for selected
 regions. The curves in Figure 3 show the difference
 between the least-cost and a uniform  plant strategy
 that was being implemented. Even though the least-
 cost strategy  is economically  most efficient,  there
 may be political or institutional constraints that pre-
 vent it from   being  used.  Nevertheless, least-cost
 functions  should   be  derived  in  all studies  so the
 decision maker realizes what is given  up to  accom-
 modate these other factors.


  As stated earlier, when  a decision is made,  the ad-
vantages  and  disadvantages  of that  decision  and
 alternatives to  that decision have been compared,
 either explicitly or implicitly. In this process of com-
 paring  advantages   (benefits)   and  disadvantages
 (costs), it is useful if they are measured in  the same
 units. Although many  different  units can  be used,
 monetary  units  have  many  advantages.  One  ad-
 vantage is that  many of the effects are measured in
 monetary units  such as the costs of  add-on control
 equipment and medical  expenses from pollution dam-
 age.  Another is that the monetary units are easily
 understood. The difficulty of measuring all the  ad-
 verse  and beneficial  effects in economic terms  has
 been discussed.  In practice, it may be necessary and
 desirable to present the decision maker with several
 functions,  measured in different units, i.e., number
 of  premature  deaths,  hours  of  suffering,  reduced
 employment, etc. Here it is assumed that they can
 all  be measured in economic (or other  unit) terms
 so  that  determining  the  socially desirable  level  of
 pollution can be  explained. Later, this assumption
 will be relaxed  and the process of making  trade-off
 decisions when effects are measured in different units
 will be explored.

  In making decisions  about the acceptable level of
 control,  the change in  damages  must be compared
 to  the changes  in costs for a proposed change  in
 ambient quality. These  changes  are called  marginal
 damages and marginal costs. Marginal damage func-
 tions and the negative of the marginal cost functions
 with their associated variance are presented in Figure
 4. The negative of the  cost function is  used  to  get
 both  marginal functions in  a single quadrant. Both
 sets of data, the costs  and the benefits, have been
 annualized so the figure depicts  costs and  damages
 per year. Point P, in Figure 5 represents the socially
 optimal level of pollution control. Except  for very
 unusual situations, that level of  control  will not be
 zero emissions,  zero effects, or  uncontrolled emis-
 sions,  zero effects,  or  uncontrolled  emissions.  At
 Point  P,  the marginal  costs are just equal to the
 marginal damages. It can be demonstrated  that the
 point where the marginals are equal is the optimum
 level. The procedure for determining the  optimum
 point is not different for a  damage function with a
 threshold like function  B in Figure  1.

  The A', A" and C,  C" functions  reflect  the fact
 that neither the  cost function nor the damage func-
 tion is known  with certainty. The shaded  area in
 Figure  4  shows  the  area within  the  confidence
bounds of both functions.  Because of uncertainty,
any pollution level corresponding to  a point in the
shaded area could be the optimum level. Thus, the
optimum level could, with the confidence implied by
the  confidence  bounds, be  somewhere between  P2
and  P3. The more uncertainty we have about the
damage and  cost  functions, the  larger will be the
range that contains the  optimum  level and the more

1    .



3    2

              10       20       30      40       SO       60

                           PARTICIPATES, MICROGRAMS/M3

                            FIGURE!  COST FUNCTIONS
                P2   PI
                            LEVEL OF POLLUTION
                                                           A (MARGINAL DAMAGES)


    PA   PO
                                     PA    PO   PB
                    PA   PO   PB
    PA   PO   PB
                      , "B
  j  GB
    PA   PO
                            FIGURE 5. DAMAGE AND COST FUNCTIONS
                                    PA   po   PB
difficult for decision makers to choose an acceptable
level of pollution with confidence that it is near the
correct level.
  The  current state-of-the-art  in  estimating both
costs and benefits does not allow the ideal of getting
    all the effects collapsed into a single functional form
    so that the optimum decision point  can be easily
    determined. In  fact, many of the effects simply can-
    not be  measured at all. As stated  earlier, many of
    the costs, particularly when emission  control is ob-
    tained by relocation  or by changing the process or
    the product quality,  also have not been measured.
    So, the decision maker has to settle for estimates of
    some key effects that are not in comparable units.

For health damages there are three key relationships:
number of years/days  lost because  of  premature
deaths, the total health costs  including doctor and
hospital costs and lost days of work, and  the hours
of suffering from sub-clinical effects, each as a func-
tion  of air pollution  levels. Four key variables on
costs  are the total costs of add-on  equipment with
the associated operating and maintenance  costs, the
number of plants forced out of production, the de-
creased employment in the region, and the foregone
benefits of economic growth. The two key variables
for environmental  pollution costs are psychic costs
and economic value of avoidance and damage costs.
Hypothetical  functions for these nine functions are
shown in Figure 5.
   The level of exposure P0 results from the existing
level  of pollution.  This  becomes the base-line case
for the analysis. Decision  makers could use a set of
functions as depicted in  Figure 5 to make  their own
trade-off  decisions. However, there are many trade-
offs involved, and it may be easier if selected results
were  displayed  in a table. Results for several alter-
native control levels can be presented in such a table.
Examples are shown in  Table 2. Alternatives A and
B are shown. The values in the cells are the changes
from  the base case.
   Alternative A considers a reduction in  exposure
levels. Thus,  in comparing it with the base case, the
tradeoffs   are  fewer  premature  deaths,   (Do-Da),
fewer hours of suffering, (So-Sa), lower health costs,
(Ho-Ha),  increased psychic  benefits (Bo-Ba) and
reduced  avoidance  and  damage  costs   (Ao-Aa);
traded off for higher control costs (Co-Ca), reduced
regional  growth (Go-Ga), increased plant failures
(Fo-Fa),  and  increased  unemployment  (Uo-Ua).
A decision maker would have to weigh these different
effects to determine  overall  costs  and benefits of
Alternative A.
  Alternative B presents similar tradeoffs from  al-
lowing pollution levels to be worse. Many alterna-
tives could be presented to the decision maker in this
format. Also, the number of effects can be increased
to include important  subsets.  If it were important
to the decision maker to know how  premature deaths
were distributed between young and old,  separate
functions would be generated and separate rows pre-
sented in the table.
  The procedure described above demonstrates how
information  for cost-benefits (trade-off) analysis can
be presented to decision makers  when  there is a
problem of weighing the different effects.  It assumes
that functions are available for these effects.  In fact,
very few functions have been estimated.

  Cost-benefit analysis has been used for many years
as a decision tool for  water  resource projects. Much
of the current state-of-the-art of cost-benefit  analysis
for environmental objectives has come from this ex-
perience. However, environmental cost-benefit analy-
sis requires estimates of many benefits not important
to water resource decisions.
  Cost-benefit analysis is required in many of  the
laws governing the establishment  and enforcement
of acceptable  levels of control. However,  require-
ments for its use vary considerably.
  In the laws governing the primary ambient level
of air pollutants, the level  is  to be determined by
threshold health effects,  and costs  and benefits  are
not to be considered. As  it becomes clear that thres-
holds do not exist or are very low, consideration is
being given  to shifting to a cost-benefit criterion for
determining  levels.
  Special laws were passed requiring emissions from
mobile sources to be rolled back 90%, with limited
                       Table 2.  Selected Results From Damage and Cost Functions
                                                                        Alternative Control Targets
Number of Premature Deaths

Hours of Suffering

Health Costs ($)

Number of Plant Failures

Control Costs ($)


Regional Growth

Other Benefits

D -D
0 A
H -H
0 A
F -F
C -C
U -U
G -G
B -B
D -D
0 B
S -S
F -F
C -Cn
u -u
G -G
O~ B

 consideration of the costs or benefits in setting this
 level and date of attainment. Similarly, very stringent
 transportation controls are being relaxed  and post-
 poned, in cases where it has become  apparent that
 the  social costs would be very high.
   The laws considering water  quality vary in their
 requirements for  cost-benefit analysis. All plans by
 states to implement water pollution programs are re-
 quired to be evaluated in a cost-benefit analysis and
 others require such analyses to  establish effluent dis-
 charge limits. If individual firms believe the costs of
 complying with the limits exceed the  benefits, they
 can request  a cost-benefit analysis; and if costs ex-
ceed benefits, they do  not have to comply at that
  Limits  on toxic substance emissions  to  the  en-
vironment are to be established  on the basis of cost-
benefit analysis.  Determination  of whether  a  pesti-
cide can  be used has  to be made after consideration
of the costs and benefits.
  Although  requirements for  cost-benefit  analysis
vary among pollutants and change over time, increas-
ing  consideration is being given to using it more in
making decisions. The  need for improved methods
and  improved  data,  particularly  dose-response re-
lationships,  is increasing rapidly.

                Methods  for Abatement of Water  Pollution
                                       Robert B. Schaffer *

  The comprehensive  environmental  analysis of a
denned  area requires the  assessment  of all  sources
of pollution, their interrelationships  and  ultimate
control possibilities. This paper has two objectives:
  1.  to provide the participants of this symposium
      necessary  information  on  water  pollution
      sources and  associated control strategies; and
  2.  to look at some of the more conceptual strat-
      egies that may be  termed  Operational Con-
The  former information includes  the  description  of
levels of control and their cost for some represent-
ative industrial  categories  and the municipal or do-
mestic  waste  source.  The  diffuse  or  non-point
sources  cannot be  as  precisely scoped. The infor-
mation,  therefore,   will only provide data  for de-
cision-making  and not  make  the decisions.  The
strategies  employed in Operational  Control must
integrate the technologies  described and incorporate
them in the decision-making process through  the
development of basin or region plans. Specific data
on  the  relative  costs  and  socio-economic  benefits
have not been included, but they must be  weighed
with all other aspects  of  the overall  environmental
plan. Many social  and legal/regulatory factors must
also be  considered, and some of the obvious will  be
briefly discussed.

   Point sources of pollution from municipalities, in-
dustry, commerce, and agriculture are the most con-
trollable and best lend themselves  to  the improve-
ment of water quality  in  a  cost effective manner.
Technology is available to achieve  the reduction of
most pollutants, to the  limit  of detectability, if cost
is no object. However, this option is  not generally
available,'and other alternatives must be  considered.
   The single variable that provides the most poten-
tial  for achieving the greatest removal  from point
sources is  time. A long-range strategy must be de-
veloped for the region to achieve maximum control
at the  lowest cost. The objective is  to do the  best
job you can economically, not to get by as inexpen-
sively as possible, which is  the tendency  when op-
posing interests attack a common problem.
   The optimum point source control strategy  then
should have as  its goal zero discharge of pollutants,
defined as the removal of undesirable constituents of
wastewater to levels  of detectability. Zero discharge
does not mean the removal  of all  constituents nor
the elimination  of the liquid discharge itself. In these
instances primarily,  but  in  all others  as  well,  the
pollutants so removed from discharges to waterways
become materials of  concern in other environmental
areas.  They may become  air pollution  problems
through incineration, solid waste problems through
conversion and disposal  to  the land, or a problem
due to their presence in products produced for con-
sumption  and  use.  A  water-borne  discharge  may
turn out to be  the best ultimate disposal option for
the overall environment.
   The most complex and difficult problems  in de-
velopment  of an  effective environmental assessment
of an area are  associated with an industrialized so-
ciety. Treatment  or  abatement technologies for the
varied and necessarily complex manufacturing proc-
esses stretch the  limits of existing technology when
viewed in  the  context  of zero pollution. Whether
municipal  or industrial,  a certain  amount of that
which results from man's industrial society must be
   One basic, but often forgotten, law in relation to
pollution control is the conservation of matter. Many
would have those  materials  that present environ-
mental problems  just disappear. Unfortunately, they
will not, no matter  how  hard we try. There is no
such  thing  as  infinite recycle  or  reuse. Therefore,
difficult  technical,  social and economic  decisions
must be made with regard to each specific problem.
   The goal of zero  discharge must  be  approached,
therefore, in a step-wise fashion; Public Law 92-500
outlines  the pragmatic,  technology-based  approach
now underway  in the United States.
   1.  The application of Best  Practicable Control
      Technology Currently Available  to all exist-
       ing point sources  other than  publicly owned
  •Permit Assistance and Evaluation Division, U.S. Environmental Protection Agency

       treatment works, i.e., the average of the best
       practiced  technologies to be  in  operation  by
       July 1977;
   2.  The application of the Best  Available Tech-
       nology Economically Achievable, i.e., the best
       that could be built using possible scale-up of
       pilot technology; to be in operation by 1983;
   3.  The application of the  Best  Demonstrated
       Technology,  including use of different manu-
       facturing processes, to all new sources;
   4.  The application  of pretreatment requirements,
       which  must  control incompatible  pollutants,
       on discharges to municipal treatment systems;
   5.  The application  of secondary treatment to  all
       existing municipal systems, this step on  the
       same time frame as Step  1 for other types of
   6.  The application  of Best Available Technology
       to  municipal  treatment works, this step to co-
       incide with Steps 2 and 3.
   The application of this strategy is complicated  by
 the  diversity  of  industrial categories and  the ability
 of technology and  economics to  cope with  these
 problems. In some categories it will be  impossible
 to achieve complete recycle and  may well  be un-
 desirable. This  paper  examines, for  purposes  of
 illustration,  the   application  and  costs of  various
 levels of  pollution  abatement  in different  industrial
 and municipal situations. Both major industrial  seg-
 ments shown, Iron  and Steel  and Petroleum Refin-
 ing, do not provide  for the goal of zero discharge  of
 pollutants.  Petroleum refining  effluents can be con-
 trolled more  easily, primarily due  to the technical
 sophistication associated with  the processing of the
 raw materials into  the  various  products. The Iron
 and Steel Industry  requires high volumes of water
 for cooling and  quenching and presents a less con-
 trollable  option,  from  a water  recycle standpoint.
 The Metal Finishing category  presents  the "no dis-
 charge" option,  primarily because  of  its size  and
 product recovery economics. In this instance, Step
 2  (Best  Available  Technology) will be  equal  to
 Step  3 (New Source Requirements) which  is zero
   The  treatment  of municipal wastes using existing
 technologies takes us up to the renovation of water
 for beneficial  reuse.  Effluent quality  may be tailored
to the use required,  from water quality  maintenance
through various  stages  of water  reuse.

Petroleum Refining

   A petroleum refinery is a complex combination  of
interdependent operations, and the characteristics  of
the wastcwater differ considerably for different proc-
esses. Each process is itself a series of unit operations
which causes  chemical and/or physical changes  in
the feedstock  or products, and each operation may
have  drastically  different  water  usages associated
 with it. Table  1  shows the discharge concentration
 averages for both Best Practicable and Best Available
 levels of treatment. The difference  in the amount of
 pollution discharged in this case is related to a  sig-
 nificant reduction in  the volume of water  used  per
 unit of production for Best Available Treatment.

 Iron and Steel Industry

   The industry is comprised of a complex of manu-
 facturing processes and wastewater treatment oper-
 ations, both biological and physical-chemical, which
 may be used. The proposed Best Available levels for
 the Iron and Steel industry indicate that it requires
 and will continue  to require large volumes of water
 for the  manufacturing process. Therefore, in long-
 range planning, this consideration must be integrated
 into the ultimate location of the manufacturing facili-
 ties. Tables  2 and 3  show the discharge concentra-
 tion averages for  the industry for Best  Practicable
 and Best Available levels.

       Table 1. Petroleum Refining Industry
    Attainable Concentrations  from the Application of
 Best Practicable  Control Technology Currently  Available
               Best Available Treatment
Annual Average
Biochemical Oxygen Demand
Chemical Oxygen Demand
Suspended Solids
Oil and Grease
Ammonia Nitrogen
Chromium, Total
Hexavalent Chromium
          Table 2.   Iron and Steel Industry
     Attainable  Concentrations from Application  of
 Best Practicable Control Technology Currently Available
Biochemical Oxygen Demand (BOD8)
Suspended Solids
Oil and Grease
Ammonia (as  Nitrogen)
Cyanide, Amenable to Chlorination
Chromium, Total Dissolved
Iron, Total Dissolved
Zinc, Total Dissolved
•With Recycle
Metal Finishing

  The basic treatment model is that of unit process
stream precipitation. For essentially all of the param-
eters, Best Practicable involves precipitation,  which
includes  coagulation,  sedimentation,  flotation,  and

         Table  3.  Iron and Steel Industry
      Attainable Concentrations for Application of
Best Available Control Technology Economically Available

          Parameter                       (mg/) *
                    Table 4. Reclaimed Water Quality
                        First Year of Plant Operation
                      South Tahoe Public Utility District
Biochemical Oxygen Demand
Suspended Solids
Oil and Grease
Ammonia (as Nitrogen)
Cyanide, Amenable  to Chlorination
Chromium, Total Dissolved
Iron, Total Dissolved
Zinc, Total Dissolved
•Treatment of Recycle Slowdown

finally,  filtration.  Evaporation recovery and ion ex-
change  offer other effective approaches, and in some
cases, chemical oxidation (for cyanides)  and chem-
ical  reduction (for chromium) are needed as part
of the treatment process.
   The  costs of achieving effluent reduction to "no
discharge"  have  been  examined for the  industry.
The cost may be  about the same as for conventional
chemical  treatment because it  may  be possible to
recover and reuse sufficient chemicals and water to
offset the costs of treatment.

Municipal Wastewater Treatment
   In making determinations with regard to handling
of domestic wastewaters in the context of  area plan-
ning, certain considerations become more important
than others. First, the  combination  of  compatible
industrial wastes may present economical solutions
and must be considered. Secondly, the existence of
defined areas of  development may limit the choice
available, usually on social  and economic grounds.
Thirdly, where new systems may be  designed, there
are  fewer constraints on renovating water for  reuse.
   Of immediate  interest in the handling of waste-
water management problems  in areas already  under
development is  the  upgrading of present treatment
plants.  Technology in the past decade has provided
many innovative upgrading  procedures to meet de-
ficiencies in existing processes. Performance and cost
data on  the  upgrading  of  facilities  have   been
   The  consideration  of advanced  waste  treatment
processes for water renovation  and  potential reuse
can result in  a viable, economical alternative. Suhr
has described cost  and performance  data for the
South Lake Tahoe  Public  Utility  District.  The re-
sults of treatment meet or exceed the stringent re-
quirements  imposed. These results are summarized
in Table  4.
   All areas do not require  the same  degree of waste
treatment,  and all of the tertiary processes utilized
at  Lake Tahoe are not required at each proposed
tertiary treatment plant. Because they are unit  chem-
            Quality Parameter
BOD mg/1                   1.0
COD mg/1                   10.8
Phosphate (as Phosphorus) mg/1 0.42
Jackson Turbidity Units        0.6
Suspended Solids mg/1         0.5
Coliform MPN/100 ml        2.2
No two consecutive
samples greater
than 16.
ical processes,  the Tahoe processes can be adapted
to provide treatment to meet almost any practicable
pollution  abatement criteria.
   The overall  consideration of point source control
is summarized in Figure 1. Considerations for the
implementation of pollution abatement beyond Best
Practicable, which is assumed to be the base accept-
able level, must  consist of an area's  water use re-
quirements, volume available, water quality, and the
assimilative capacity of these waters to maintain de-
sired  quality. In general, the costs for achieving the
next level, that is, Best Available Treatment, will be
roughly three times the  cost of Best Practicable.
   To go beyond, to approach zero discharge of pol-
lutants, will increase the cost significantly. The de-
sirability  of this  option, where technically feasible,
will depend directly on the value of the water in that
specific location.

   The  fact  that  nearly all non-point  sources are
rainfall/runoff dependent  and  are associated with
highly  variable natural phenomena  has  profound
implications  for their control. It  is extremely diffi-
cult to characterize a non-point source or evaluate
control performance  dependent on  such  variables
as rainfall and growing season which cannot be pre-
determined, controlled or  accelerated.  Accurate as-
sessment  of the  problem  may require a  significant
period  of time (one  to  three years).  Because there
is no typical year or season, a multiyear study may
be required.
   Non-point sources  have  enormous  diversity. Dis-
charges are noncontinuous  and highly dependent on
location and local conditions. No  single  set of con-
ditions would  be representative,  and an  extrapola-
tion  of data from  specific studies is risky.  These
sources have no  defined discharge point  and cannot
be conveniently or economically measured. The dis-
charge or load must be related to some measurable
source  feature or activity. Because control  by ef-
fluent treatment  is impractical in  most instances, we
must control the activity by causing a change in the
pollutant's manufacture or use. Source control prob-
lems involve signivcant institutional, legal, and socio-
economic interfaces.

        (10 Years
      (5 Years)
                                            POLLUTION %

                        FIGURE 1. RELATIVE COST OF IMPROVING
                                    WATER POLLUTION CONTROL
Proposed Control Strategies
  Relief from non-point  source pollution requires,
as a first step, the assessment of the problem in order
to set proper program priorities. The leading models
for  non-point sources  and representative  land  use
patterns should  be developed.  The probably  effec-
tiveness of available control options must be assessed.
Basin load allocation models must be developed to
allow trade-offs  in individual situations between the
control of point sources  and non-point sources.
  The following is a brief discussion of six specific
non-point source areas.

Irrigation Return Flows

  This water quality problem involves all irrigated
agriculture, including water and crop  management
procedures  and  accompanying  use  of  chemicals.
Major  pollutants  from return  flows include salts,

sediments,  nutrients, toxic and other bioactive  ma-
terials. The magnitude  of the problem is indicated
by  the fact that approximately 10  percent of the
cultivated acreage in the United States is  under irri-
gation, producing 25 percent of the national food
and fiber. Doubling of irrigated acreage by the year
2000  with a 10-20  percent increase in  total water
use is projected. With  existing  practices, total salt
discharged could double. Salt has extensive effects on
agriculture to the extreme of rendering  farm land
no  longer  productive. Fifty  to  seventy   percent of
man-induced salt sources in  receiving  waters  can
come  from irrigation  return  flows. This pollutant
will present a major interbasin problem and can af-
fect international uses  of water. Control strategies
must  consider soil and  water management practices
in each climatic/geographic location and the strategy,
therefore, will  vary  with location.  Source  manage-
ment  is the most cost-effective general control option
now available, entailing water management as  well
as  the management of  the  application  of  various
chemicals used in irrigated agriculture.

Animal Feeding
  All animal raising operations produce pollution
from  the  oxygen-demanding  materials,  nutrients,
salts,  and  pathogenic  organisms  present in waste
waters from the  operations, with significant impact
in any basin where  such activity is  a major factor.
Present  trends relate  to the economics of larger
operations. In the United States sixty percent of the
marketed beef cattle are produced by fewer than two
percent of the operations. Control strategies for many
operations include  land  disposal of residues  pro-
duced, and containment and spray  irrigation  with
water resulting from such operations. The economics
of  hauling wastes,  and  climate are problems here.
An ultimate solution is likely to be by-product re-
covery and land disposal of effluents.

Agriculture Runoff
  This segment  includes crop raising, animal  pas-
turing, forestry  and other rural land uses from all
nonirrigated  agricultural  operations.  Major  pol-
lutants include sediments, nutrients, oxygen-demand-
ing materials, organic and inorganic residues from
agricultural chemicals,   toxic and  other bioactive
materials, heavy metals, and pathogens. This activity
in any given basin may cover at least fifty percent
of the land area, resulting in  significant  amounts of
pollution due to runoff from precipitation. The trend
towards  sharply increased agricultural   production
both  in acreage and in productivity is likely to ac-
celerate pollution by use of marginal lands and  even
greater amounts of chemicals.  Control strategies
focus primarily on  source control management, but
highly variable and complex  conditions make con-
trol of this diverse  situation very difficult.

Hazardous Material Spills
  Hazardous  materials production, storage,  trans-
portation, or utilization in close proximity to a water
source provide a potential hazard to water quality.
Major pollutants from spills are toxic and other bio-
active  chemicals,  acids, alkalies, corrosives, oxygen-
demanding materials, and petroleum oils and related
products.  The significance of  the  problem is mani-
fest, but its magnitude is  difficult  to assess. Control
requires detailed,  comprehensive planning and action
response capabilities to minimize  harmful effects.

  All  surface  and underground  mining  activities,
including  milling, benefication, and  other site  oper-
ations,  are  sources of pollution. Major pollutants
include sediments,  acids,  toxic  metals,  and  other
salts.  Increased demands for energy and all types of
minerals will result in increased impact of active
mining operations.  Long-term  problems  will con-
tinue   as  our requirements continue  and increase.
Control strategies,  depending  on the source, include
surface reclamation and specific collection and treat-
ment of discharges. Coal  mine drainage treatment,
for instance, is costly but not unreasonably expen-
sive. An associated problem is pollution from  aban-
doned mines. Nonoperating surface and underground
mines,  including refuse  and  tailing  piles,  provide
significant pollutant amounts. Control is often dif-
ficult because specific sources cannot be identified.

Land Modification
   All of man's  activities which  alter land surface
and thereby  facilitate runoff  (construction,  land-
filling,  etc.)  produce significant amounts  of pol-
lutants, primarily sediment carried by surface runoff.
The impact of these activities is a universal problem
related to overall area economic development. Sedi-
ment is both a physical pollutant and a carrier for
other  pollutants. Source  controls are the only  ap-
parent promising operations for the control of runoff
from construction.  Conditions vary  widely, but they
must be seriously considered  in the development of
any type of regional plan  that expects to significantly
modify existing land use  patterns.

   Wastewater treatment  technology describes alter-
natives available to achieve a desired result through
its  application to  point sources.  Non-point sources
may  limit  the  potential  for  achieving  all desired
water quality goals through point source control
alone.  Other avenues for the achievement of the

 optimal water quality  must be  assessed,  and these
 fall into  the  area  of operational  control.  Some of
 these alternates and  how they may be incorporated
 into the overall plan  are examined here.

 Non-Point Source Alternates
   Since there are no  easily or rapidly achievable
 means  of overcoming non-point source pollution, it
 seems  most  important to  incorporate some basic
 principles  into  the long-range  objectives.  Some of
 these basic principles or concepts  are:
   1.  the establishment of land use requirements to
      minimize the  concentration of  industry  and
      other associated  development;
   2.  modification of agricultural practices to mini-
      mize runoff and  the  associated  pollutional
      problems of silt, fertilizers,  pesticides, herbi-
      cides, and organics; and
   3.  the control of area runoff (stormwater) which
      can  be as much of  a pollutional load from
      urbanized areas as the wastewater produced.

 Land Use
   The  establishment  of land use requirements  may
 well be the most difficult and certainly most com-
 plex problem facing  an areawide planner. An opti-
 mum system  for one purpose, water pollution  con-
 trol, is  not adequate.  Other environmental concerns,
 such  as air pollution control  and solid  waste dis-
 posal, are important  as well as considerations  of
 traffic flow, recreational and aesthetic requirements.
 Other less obvious  factors are the location of natural
 resources,  i.e., one must locate a mine where  the
 minerals are,  transport  the product to the market,
 supply resources, and provide support functions.
   The benefits of establishing a good land  use  plan
 from  a  water quality  standpoint  are tremendous.
 Minimizing the stress  of pollutants  on water  re-
 sources through selective locations will give this part
 of the ecosystem a chance to stabilize, that is,  reduce
 the rate of degradation.

   Because the  choice  of location  for agricultural
 activity  is normally limited in any given basin  by the
 availability of suitable lands, the potential for  opera-
 tional controls becomes more important. Agricultural
 non-point source water  pollutants come in large  part
 from  natural  runoff.  Pollution prevention  must be
 achieved through  the  management of  agricultural
 practices in  cropping  pasture,  forestry  and other
rural  land  uses. The  basic problem, to manage  for
proper  operational changes  to minimize  pollution
without  decreasing productivity,  is further compli-
cated  by  such  uncontrollable  natural factors  as
climate,  topography,  etc.  Nevertheless,  significant
 progress can be made. Contour farming methods and
 the proper application of fertilizers and  other chem-
 icals  can materially  reduce pollutants reaching the
 water. As in all operational control areas manage-
 ment models can effectively be used for characteriza-
 tion and  load reduction predictions. The degree  of
 control attainable  will be somewhat less than that
 for other  sources because of the diverse nature of the
 problem.  Even so, the potential water quality gains,
 especially in areas  affected by toxics, eutrophication,
 and silting, can be  well worth the effort.

 Area Runoff

   Area runoff, water resulting  from rainfall  con-
 taminated by contact with man's urbanized and sub-
 urbanized activity,  results in more diverse pollutants
 than  other  non-point sources. Street runoff  (con-
 taining oil, motor  vehicle  exhaust  chemicals),  park
 and lawn  area runoff (fertilizers and toxic organics),
 and  construction   site runoff (silt from disturbed
 areas) will equal or exceed pollution from municipal
 wastewaters.  The volume of water  can be extremely
 high,  depending on the location and degree of cover-
 age (e.g., concrete).
   Flows of this type collected in storm or combined
 sewers present a significant point source  of pollution
 that  is rarely effectively controlled. The only  prac-
 ticed technology on these large volume point sources
 is brief settling and  skimming. Lower flows or the
 "first  flush," can be routed to municipal or industrial
 treatment plants.
   Manufacturing facility runoff adds to the complex-
 ity of the wastes, with material spills, and with run-
 off and/or leaching of storage piles capable of con-
 tributing  extremely high  pollution  loads. Available
 control methods include management  of flow  (e.g.,
 dikes), routing of  certain types of flows (e.g., roof
 drains), and  covering of refuse or storage piles, etc.
   Combined  sewer separation,  and in  developing
 areas, the construction of separate storm drains and
 sanitary sewers, is the best solution from a pollution
 standpoint. The economics of separation in urban-
 ized/industrialized  areas  may be prohibitive.
   Effective operational control of non-point sources
 will require time and good management. Some  of
 the management techniques  will include long-range
 planning,  turning non-point  sources into more  con-
 trollable point sources, and significant predictive and
 management  modeling.

 Water Management

   Optimum water  management in urban areas re-
quires the serious consideration of water renovation
and reuse, particularly  in  water-short  areas.  The
supply of  water is  static geographically, unless di-
verted by  man. Will man move to water or develop

the techniques to supply water where he lives? Tradi-
tionally, man has remained relatively immobile. Pol-
lution patterns in 2070 will  probably be  similar to
today's. The total supply of water is about the same
as it was when the earth was very young and it will
be the same tomorrow!
  The ultimate in recycle  or "closing the loop" is
recycle of public wastewater directly back to the sup-
ply.  Psychological factors inhibit this type of reuse
despite technical capabilities.  Reuse of another city's
effluents by a downstream city doesn't seem to bother
us as much, though. In other words, the use of an-
other's treated sewage is acceptable, whereas the use
of one's  own treated sewage is unacceptable. Ad-
vanced  water purification  technology  destroys  the
"logic" of this traditional attitude.  A clear, tasteless,
odorless water can be produced. This "reuse reluct-
ance" has caused many cities to go to great  expense
for alternative water sources, such as building large
reservoirs and transporting water hundreds of miles.
  When  faced with  a  decision on  where to go for
increased water supply, the existence of these many
alternative  schemes makes  selection of the best one
extremely difficult.  Many technical, economic, and
policy questions must be answered. Actual conditions
may cause  many of the options to "drop out," mak-
ing the best alternative obvious by inspection.

  A brief mention of some important non-technical
aspects  of integrating  water pollution  control into
an environment plan is an appropriate way to con-
clude this portion of the overall assessment. Probably
one of the most frustrating problems may be termed
legal or  jurisdictional.  Conflicts will arise, for  in-
stance, when one part  of  an optimum water system
must suffer due to the need of a transportation system
or vice versa. Bureaucratic battles can be predicted
when one local  jurisdiction must,  for instance,  be-
come the repository for  the waste  materials  from
another jurisdiction.
  Depending  on the  existing form  of government,
personal  property rights, resources rights, water laws,
and industrial interests  can serve to delay and change
the optimum plan.
  Consequent legal  challenges are  as  much of  a
stumbling block  to the orderly progression of a plan
as any technical problem.

   Technology is available to make great  strides to-
ward improving  water quality  in a  cost effective
manner through point source control. Methods for
the control of non-point sources provide  less of an
opportunity to  achieve  control in the  immediate
future and will require continued research and de-
velopment to develop and perfect control measures.
The longer range goal of zero discharge of pollutants
will be dependent upon the development of new and
more sophisticated pollution abatement techniques.

                  Methods for the Control of Air  Pollution

  The control of air pollutant impacts is a complex
problem because of the variety of sources and source
characteristics. Technical and  economic factors fre-
quently make it necessary to use different control
procedures for  different  types  of sources.  Many
emission control techniques are still in the develop-
mental stage, and  practical near-term control  strat-
egies may call for the  use of  interim methods until
these  techniques are perfected. In these situations,
alternatives, such  as the  use  of  design and  siting
criteria which distribute rather than limit emissions,
may be required as a means for achieving air quality
goals. Therefore, fundamental to the development of
either Air Quality Management or widespread source
control strategies for the achievement of air quality
goals  is an understanding of the performance, cost,
applicability and availability of potential control al-
ternatives.  This  paper will   consider  these  basic
factors as they bear on both technical and opera-
tional emission control  as well  as emission dispersion
   These considerations will begin  with  a discussion
of the air emission inventories associated with sta-
tionary and mobile source categories and their rela-
tionship to ambient air  quality and proceed to discuss
the status of  control methods  for (1) sulfur oxides,
(2) total suspended particulate, (3) fine suspended
paniculate, (4)  nitrogen oxides,  (5) hydrocarbons
and oxidants, and (6)  carbon monoxide.

   Table 1  summarizes the contribution  of  source
categories contributing  at least  one percent  to the
inventory of six major  air pollutants in the  United
States.  With the exception  of fine  suspended par-
ticulate, health related ambient air quality standards
have  been established for each  of  these pollutants.
Fine suspended particulate (less than 3  microns) on
the other hand has been shown to be potentially the
most  offensive particulate size fraction because it is
more easily respirable  and more readily  retained
in the lungs as well  as having the ability to persist
for extended periods  in the atmosphere.

Sulfur Oxides

   Over  60 percent of the  total  sulfur oxides emis-
sions result from the combustion of coal, primarily
in large  electric  generating facilities. About two-
thirds of the nationwide emission occurs in urban
areas with  power  plants, industries,  businesses and
homes all contributing to the burden. Much of  the
pollution in rural areas is emitted  by  a relatively
small number of large  individual sources. For  ex-
ample, individual  smelters, generally located  away
from metropolitan areas, may emit over 100,000 tons
per  year.  In addition, almost half of the Nation's
power  plants, including  seven  of the eight largest
sulphur oxide emitters, are located in rural areas. An-
nual emissions from these seven range from 200,000
to 300,000 tons per  year.

Nitrogen Oxide

   Motor vehicles and the statutory  combustion of
fossil fuels account for about 90 percent of the  na-
tional total. Nitrogen oxides and carbon monoxide,
probably more than  other pollutants, are closely re-
lated to the distribution of  population. It is not sur-
prising,  therefore, that over 60  percent of nitrogen
oxide emissions occur in urban areas. In terms of
sources, only about 45 percent of the nitrogen oxide
emissions  from  motor vehicles  are  in urban  areas
because, unlike carbon monoxide and hydrocarbons,
they are relatively unaffected by  travel speed.
Carbon Monoxide

   Petroleum-powered motor vehicles  are the largest
single  emitters of carbon  monoxide. Although ve-
hicular travel is evenly divided between urban and
rural  areas, traffic  in  urban  areas,  where slower
driving speeds prevail,  accounts for  70 percent of
total motor vehicle carbon monoxide  emissions.
  •Chemical Engineer, Office of Research and Development, U.S. Environmental Protection Agency

                                               Table 1
                         1970 United States Air Pollutant Emission Contributions
                                          by Source Category

Stationary Combustion
Electric Utilities
Indusrtial Combustion
Residential & Commercial
Pipeline Pumping
Motor Vehicles
Industrial Processes
Carbon Black Manufacturing
Chemical Manufacturing
Grain Handling
Iron and Steel
Mineral Products
Nonferrous Metallurgy
Petroleum Refining
Pulp & Paper Manufacturing
Sulruric Acid Manufacturing
Solvent & Petroleum Product Evaporation
Natural Sources
Forest Fires
Controlled Burning
Natural Dust
Million Tons/Year Total Emissions (all categories)






















Total Fine
Suspended Suspended
Paniculate Paniculate
4 9
3 7
1 2

1 6
1 0
8 15

1 4
5 8

1 2

86 70
26 21
14 11
46 38
136 5
   Of the sources  surveyed, in the absence of con-
 trols, motor vehicles would again be the largest single
 emitter category. There  are fundamental difficulties
 involved,  however,  in  simultaneously  eliminating
 hydrocarbon,  carbon  monoxide and  nitrogen oxide
 emissions from mobile sources. Specifically, the  car-
 bon monoxide and hydrocarbon emissions could be
 reduced by  increasing  the ratio of air to fuel to the
 point where more  air is present than  is required for
 complete  combustion of the  fuel to carbon dioxide
 and water.  Maximum  emissions of nitrogen oxides,
 however,  would occur under  such conditions.  On
 the other  hand, at very low air-fuel ratios, the nitro-
 gen oxide emissions could be reduced but high con-
 centrations  of carbon  monoxide  and  hydrocarbons
 would be  produced. At  the extremely high air-fuel
 ratios where all three  emissions could theoretically
 be  low,  operating  difficulties such as misfire  and
 stalling  would be  encountered with most  commer-
 cially available  internal combustion  engines.  This
 would result in poor performance and high emissions
 of carbon monoxide and hydrocarbons.

 Total Suspended Particulates

  As indicated in Table 1,  the  largest sources of
 particulates  are natural dusts and forest fires. These
sources  account for an estimated 86  percent of the
national atmospheric primary particulate loading on
a mass basis, and are a substantial  portion of back-
ground levels. Emissions from these sources are es-
sentially beyond  the scope  of present air pollution
control methodology. These natural emissions differ
from that found in urban industrialized areas, in that
a generally smaller percentage of particulates are in
the respirable range (less than 3 microns). Similar
fugitive or  unconfined sources  directly  related  to
man's  activity involve  agriculture, mining, construc-
tion and transportation.
  The mass of emissions from most of the industrial
sources may  be highly controlled by the installation
of presently  available control equipment. In some
cases, such as combustion of coal by electric utilities,
over 90  percent  collection  efficiency  is  routinely
achieved.  Nevertheless, because of the large amounts
of coal burned and its inherently large noncombust-
ible  particulate content, emissions  from  coal com-
bustion remain  a major  portion of the  total par-
ticulate emissions from  man's  activity.

  The overall impact of fine  particulate pollutants,
broadly denned  as particles less  than  3 microns in
size, on man's environment is not well known. How-
ever, evidence continues to point to the many nega-
tive  aspects of fine  particulate  pollution.  Research
on health effects of air pollution indicates links be-
tween fine particulate pollution and health effects of
varying severity. In addition to  particle  size, the

chemical composition of participates is an important
factor in determining the  effects  of  this type  of  air
pollution. For example, the health hazard associated
with inhaled airborne particles depends on:  (1) the
site of deposition in the respiratory tract, which is
determined by particle  sizle; and  (2)  the effect  on
biological tissues at the deposition  site,  which de-
pends on chemical composition.  The hazardous pol-
lutant  problem  (e.g., mercury, lead,  cadmium,
vanadium) is also directly linked  to  fine  particle
pollution because many of  the  industrial processes
that emit hazardous pollutants liberate them  in the
form of  micron or submicron particles. On both a
regional  and  global scale, fine participate pollutants
play a principal role  in the transport through the
air of a variety of hazardous substances. It is empha-
sized that the hazards posed to human health by trace
amounts  of toxic materials in the form of fine par-
ticulates  can be  disproportionate to  the mass  in-
   Fine paniculate  air  pollutants  may be classified
into two major classes  based on their origin.  These
are (1)  primary fine particulates which are emitted
or immediately condensed as  fine particulates from
a specific source, and (2)  secondary fine particulates
which are  the products of atmospheric reactions  to
form particulate air pollutants.

  The major concern with source emissions is their
impact on maximum ground level pollutant concen-
trations in the  vicinity of the site. Several meteoro-
logical diffusion models exist which can be used to
provide satisfactory engineering estimates of sulfur
oxide and total suspended particulate concentration
on  any given time reference  of concern. The results
of these analyses can be used to define control and
siting criteria based on the actual  contribution of
each source to  ambient air quality.
  Figure 1 summarizes this typical variation in con-
tribution to  ground level  ambient sulfur oxide con-
centration for four emitter categories. For example,
while utilities typically contribute over 50 percent of
all  sulfur oxide  emission in a local region,  well-
known factors  such as stack height may limit the
corresponding  impact on the  ground level sulfur
oxide concentrations within a few kilometers of the
emitter  to less than 30 percent of  the total.  Con-
versely,  area  and  smaller  industrial  combustion
sources typically  contribute  more  heavily to the
ground  level ambient concentrations  than would be
inferred by  their percentage of total regional emis-
  This  ability  to relate  emissions  to ambient  air
quality can be a very powerful and cost-effective tool
for (1) determining the level of control required by
source to achieve a desired ambient air quality goal,
(2)  allocating  limited emission control  capabilities
to those sources having the greatest impact on  am-
bient air quality and (3) defining new facility siting
options compatible  with  achieving  or maintaining
ambient air quality goals.
   Unfortunately, this technique  has  several limita-
tions. First, it requires an accurate source-by-source
emission inventory and  regional meteorological data
base. Second, considerable additional research is re-
quired before these  meteorological diffusion models
can  accurately  include  the effect  of atmospheric
transformation   primarily   affecting  hydrocarbons,
oxides of nitrogen, oxidants and sulfates. Third, it
may be concluded from  the emission/ambient air
quality relationships indicated in Figure  1  that peak
ground level concentrations of sulfur oxides and total
suspended  particulates may be reduced to levels con-
sistent with  ambient air  quality goals thorugh  the
relatively  simple  expedient  of increasing effective
stack  height.  Indeed,   such  considerations  have
formed  the   basis  for  "supplementary"  control
methods designed  to achieve air  quality goals in the
absence of sufficient low sulfur fuel  or control tech-
nology. This should be considered only as  a near-
term tactical expedient however.  For example,  our
current knowledge of  the  significant health effect
thresholds for sulfates and related fine suspended par-
ticulate matter infers the possible need for ground
level  ambient concentrations  that may  be eight to
ten times lower than current practice. Under these
conditions, the use of tall  stacks is  inadequate  for
achieving the necessary ground level  ambient condi-
tions and indeed  results only in subjecting a larger
ground area to excessive concentrations. This  in-
adequacy is  further accentuated  in the long  term as
a result of a continued growth of society  and its
associated  energy  needs. Unless improved  control
techniques continue to be developed and applied, by
the year 2000 it  is forecast that SOx and fine  sus-
pended particulate emissions from industrial activities
will increase fivefold. These emissions will not  only
dominate  regional conditions,  but   could produce
global  concentrations exceeding  acceptable  health


Sulfur Oxide  Control

   Beginning in  1966, both  industry and government
started working seriously to develop processes  cap-
able of removing  sulfur oxides from  fossil fuel com-
bustion flue gases.  Because of  the  operating com-
plexity and  cost  associated  with these  essentially
chemical  processing  facilities, their  practical appli-
cation  at  the  present  state-of-the-art is  limited to




             (VERTICAL SURFACES)
             CHEMISTRY (GAS-SOLID)
10-2       10-1        10°        101

                                FIGURE 1.  EFFECTS OF PARTICULATE AIR POLLUTION IN THE
                                          COMMUNITY AS RELATED TO PARTICLE SIZE

large industrial and utility steam generators (greater
than 100,000 Ibs. steam/hr—equivalent to about 10
MW). As a result of this  activity, about  a dozen
processes  have been  developed to the point where
they are being studied on  full-scale industrial facil-
ities. Nine of these processes  are variations  of the
slurry scrubbing concept using ash, lime, limestone,
or magnesium  oxide  as  the reactant. Development
results to  date generally indicate a sulfur dioxide re-
moval capability of  80-90  percent. As of January
1974,  44  commercial and demonstration  flue gas
desulfurization  installations  were under construction
or on order for use on existing and new electric
utility steam generators in  the United States. These
installations encompass 18,000 MW  of  generating
capacity at an average contract cost of $60 per KW
of controlled capacity. This represents 9  percent of
the coal and oil fired electrical generating capacity in
the United States.
   The most serious inherent limitation in the broad
commercial application of these processes is disposal
of the unmarketable waste gypsum by-product. Aside
from the  immediate spatial problem associated with
the storage and handling of this waste product, dis-
posal must be performed in a manner which does not
cause water pollution.
   The  immediate question is the extent  of com-
mercial application which can be achieved by effluent
treatment technology  and the rate at  which this ap-
plication can be achieved. The extent  of application
is essentially a question of economics. Based on field
surveys, it is theoretically possible to retrofit as much
as 80 percent  of all existing utility  and large in-
dustrial  coal  and  residual   oil-fired  combustion
sources with effluent treatment processes  for the re-
moval of  sulfur dioxides. In  reality,  however,  con-
siderations such as process packaging within  avail-
able space, by-product transport and disposal, re-
actant availability, plant capacity use factor, gas, and
size will limit the degree of application. For example,
the range of annualized SOX control  process  capital
and operating  costs  (incremental costs  of control)
required to satisfy 80 percent of existing utility and
industrial  combustion facilities extends from 100/M
BTU  of fuel consumed to  over $1.00/M  BTU.  A
practical upper bound on the ultimate extent of flue
gas control application would be about 40 percent of
large  utility and  industrial coal and residual oil
capacity.  This  level  of application would imply an
incremental effluent control cost on the  order  of
600/M BTU.
   It is clear  that the combination of natural low
sulfur  fuels and flue  gas  desulfurization  technology
will not provide the quantity and size  range of com-
bustion capacity required to achieve existing national
ambient air quality standards. Thus, a third category
of control technology, fuel  desulfurization, must also
be considered. These processes for not only desulfuri-
zation,  but  total  paniculate  cleanup of  coal  and
residual oil are required to achieve ambient air qual-
ity standards. Their basic role is twofold:
  (1) Provide  control  technology  for  combustion
sources to which other alternatives are not technically
or economically applicable;
  (2) Provide  synthetic, low  pollution  fuel aug-
menting the limited domestic  supply of natural gas.
  These approaches  range from the application  of
currently  commercialized mechanical  coal cleaning
technology, through chemical  coal and oil  desulfuri-
zation technology  which maintains  the clean fuel  in
its original physical  state, to coal  conversion tech-
nology for the  synthesis of low-  and high-BTU gas.
The  development cycle for  these latter efforts, how-
ever, restricts  commercial  application until  1978-
  Given the current limitations in the availability  of
low sulfur fuel  and control technology, the  near term
achievement of sulfur oxide ambient air quality stand-
ards can be achieved  by application of the previously
discussed ability  to  predict  emission/ambient  air
quality on  a  source-by-source  basis.  This  under-
standing  can   significantly  reduce  the  number  of
sources requiring control. A long term benefit of such
an approach is the ability to limit the very expensive
implementation of sulfur oxide  control technology
to a  few  critical sources until a better appreciation
of the technical implication of sulfate control  can  be
developed. The effects  of  these considerations has
been examined in three separate urban regions  in
which sufficient data  were available.
  For example, analysis of the 10 worst receptors in
the Philadelphia region indicated an average  annual
sulfur oxide concentration ranging  from 166 to 255
micrograms per meter3.  As  shown in  Table 2, if
controls could be selectively applied in the Phila-
delphia region, it would be  necessary to control, at a
75-percent effectiveness level, only 53 of the emitters
encompassing 19 percent of the  total regional emis-
sions to achieve the existing sulfur oxide air quality
  Extrapolation of the trends indicated in  the urban
regions examined  suggests that the existing sulfur
oxide air quality standard could be achieved in the
eastern United States by the selective control of a set
of sources using 30  percent or less of all coal and
residual oil  consumed. This extrapolation has been
supported by relating actual air quality measurements
to source fuel modifications.

Fine Particulate Control Technology
  Four major categories of industrial paniculate con-
trol   equipment  (electrostatic  percipitators, fabric
filters, scrubbers and inertial  or  centrifugal mechan-
ical  collectors) each having special  characteristics
that  determine the  suitability for  a  particular gas
cleaning application, have  been available for many

                                                 Table  2
                  Selective Reduction of SOX Emission to Achieve 80 /ig/m3—Philadelphia
Emitter Category
Industrial Combustion
Industrial Processes
Utility Power
Area Sources
Present Emissions
Sources Tons/Day
238 555
165 300
21 1345
276 4378
700 6578
Number of Sources Requiring Control at:
Sources Tons/Day
3 172
5 41
6 519
11 148
25 880
Sources Tons/Day
10 293
13 124
9 578
21 222
53 1217
years. This  presently  available  control  equipment
has  achieved only limited  effectiveness in fine par-
ticulate collection capability and i$ generally not ap-
plicable because of material limitations in situations
where co-contaminants must be dealt with.
   Efficiency data indicate that the only conventional
control devices capable  of significant collection  of
fine  particulates from  industrial sources are  high-
efficiency electrostatic  precipitators,  venturi  scrub-
bers  and fabric  filters.  Existing  data,  as well  as
theory, on fine paniculate collection  efficiency  (both
on a mass and number basis) of conventional equip-
ment indicate that inefficiency in  the fine  particulate
range is an inherent characteristic of the equipment.
Therefore, definite constraints  will be imposed on
the types of emission standards for fine particulates
that can  be implemented in the near term. These
inherent  limitations may  require that process modi-
fications  or other alternatives be used  to meet near-
term regulations.
                                       These  are three basic avenues that might lead to
                                     improved  control  of  fine particulates: (1)  droplet
                                     condensation  and  impaction; (2)  augmentation of
                                     commonly used collection mechanisms by additional
                                     forces such as thermal, diffusiophoretic and electrical
                                     which do not approach zero in the less than 3 micron
                                     size range; and (3) utilization of particle condition-
                                     ing or agglomeration  techniques producing particles
                                     compatible with conventional collection devices.
                                       Substantial improvements in fine particulate emis-
                                     sion could be achieved using currently available con-
                                     trol equipment  as  indicated  in Table 3.  This table
                                     also indicates the  relationship  of emission level to
                                     plume opacity. Table  4 indicates  that in most cases,
                                     installation of this best available technology will have
                                     relatively minor effects on overall production  costs,
                                     generally amounting to less than  one percent of the
                                     value of the product produced.
                                       The collection of fiine particulate emitted  directly
                                     from combustion or other high temperature processes
                                                Table 3
                 Estimates of Fine Particle Emissions as a Function of Emission Standard *

I. Coal combustion
(I. Iron and steel
A. Sinter machines
B. Basic oxygen furnace
C. Electric arc furnace
III. Cement plants, rotary kilns
[V. Asphalt plants, dryers
V. Ferroalloy plants
A. Closed electric furnace
B. Hooded open electric
C. Unhooded open electric
VI. Lime plants, rotary kilns
VII. Municipal incinerators
VIII. Iron foundry, cupola
Estimated Fine Particle Emissions
Lb/Hr Ton/Yr
796,000 3,184,000

7,100 28,400
400,000 1,600,000
27.400 109,600
243,000 972,000
3,260,000 1,956.000

92,000 368,000

129,500 518,000

72,000 288,000
75,800 303,200
15,000 37,500
22,900 22,900
Lb/Hr Ton/Yr
243,000 972,000

1,400 5.600
43,600 174,400
3,600 14,400
44,300 177,200
257,000 154,200

11,300 45,200

84,100 336,400

60,800 243,200
22,000 88,000
13,100 32,800
13,100 13,100
Lb/Hr Ton/Yf
15,000 60,000

64 256
2,560 10,240
645 2,589
2.000 8,000
25,600 15,350

11,300 45,200

15,800 63,200

28,800 115,200
1,200 4,800
490 1,225
356 356
10% Opacity
Lb/Hr Ton/Yr
5,050 20,200

722 2,888
1,540 6,160
1,036 4,144.
25,200 100,800
200,000 120,000



10,500 42,000
3,400 8,500
5,900 5,900
5% Opacity
Lb/Hr Ton/Yr
2,510 10,040

354 1,416
800 3,200
683 2,732
12.200 48,800
167,000 100,200



4,800 19,200
1,900 4,750
4,000 4,000
 BICD—Best  installed
 NC—Not calculated.
controls  (not neccuarily  the highest efficiency device available, but rather the beft that is generally being installed at

                                               Table  4
                    Summary of Fine Particulate Control Costs ut BICD-Level Control
                        ($/Unit of Production)—at Capital Charge Rate of 0.20
Coal-fired electric plant
Municipal incinerator
Cement plant (rotary kiln)
Asphalt plant (rotary dryers)
Iron and steel
Basic oxygen furnace
Mine plant (rotary klin)
Annual Production
Rate for Model
2.4 X 10" kwh
80,000 tons
3.0 X 10° bbls
90,000 tons
1.0 X 10' tons
87,500 tons
Fine Particle
Unit Cost
or Value
Control Cost/
Unit of
is only one portion of the fine paniculate problem.
Atmospheric fine particles which contain  sulfate,
nitrate and organic aerosols are largely formed dur-
ing secondary  atmospheric reactions  involving the
controlled pollutants subject to ambient air standards.
Conversion  of sulfur  dioxide  into  sulfate is con-
sidered to be responsible for one-half to three-fourths
of the atmospheric  particles  resulting from  man's
activities. The conversion of nitrogen oxide to nitrate
particles  accounts for  7  to 14 percent of the par-
ticulate burden produced by man, and the conversion
of hydrocarbons  has been estimated to account for
much of the remainder. The relationships are under-
stood in a general way, but they have not yet been
placed on a  quantitative basis. The nature of such
formation may be through catalytic oxidation with
heavy metal  ions, ammonia-sulfate dioxide reaction
in the presence of water,  photochemical oxidation,
and on heterogeneous  gas reactions. As a result, it
is anticipated that the control of this secondary fine
paniculate fraction may involve further control of
direct links in the chain of precursors or modification
to the physical and  chemical parameters ultimately
affecting formation. Table 5 summarizes current best
judgment  as  to the short-  and long-term thresholds
for paniculate sulfate as compared to total suspended
paniculate and sulfur  dioxide. These  data indicate
that paniculate sulfate has a threshold health effect
an order of magnitude less than sulfur oxide and total
suspended paniculate.
   The capabilities  of  current  sulfur  oxide  control
technologies are targeted at achieving moderate (30-
70 percent)  reductions in  sulfur dioxide concentra-
tion in urban areas. Unless other controllable links
in the precursor  chain can be  defined, the sulfate
levels in Table  5  imply the need for a high efficiency
control  technology (greater than  95 percent)  on
large  industrial sources and  increased use of clean
fuels in smaller combustion sources. Similarly, nitrate
control may  require improvements well beyond the
current  state-of-the-art in  nitrogen  oxide  control
   Mobile  sources contribute only about 3 percent
of the total paniculate. However, studies on the size
distribution  of  automotive exhaust indicate that 90
percent or more of the mass emitted consists of par-
ticles smaller than 1 micron. Estimated emission rates
for gasoline-powered vehicles burning fuel containing
usual quantities of tetraethyl lead (2.5  gm.Pb/gal.)
are on the order of  0.08 to 0.25  grams/mile.  Lead
free  gasoline will be required  in cars equipped  with
hydrocarbon control  catalysts  since  lead  emissions
quickly deactivate catalysts.  With  these lead-free
fuels and  catalysts, paniculate emissions will be  in
the 0.02 to  0.05 gram/mile range and may be  dom-
inated  by  sulfates  and nitrates.
   Emissions from aircraft turbines are  significant  in
some areas. Estimates of Los  Angeles  turbine  par-
ticulate emissions  are one-third to one-fifth of  auto-
mobile-generated  particulates.  Near  approach  and
take-off corridors, aircraft particulates dominate the
atmospheric aerosol. Particulate emissions may cover
a  wide range  from 0.1  to  2 percent  of the  fuel
burned, depending on  engine type  and  operating
Nitrogen  Oxide Control Technology

  The control of nitrogen oxides, as indicated earlier,
must  consider  the impact  of  both  stationary  and
mobile combustion sources. The combustion of fossil
fuels  in  air results  in  the  formation of oxides of
nitrogen  both as a result of chemically bound nitro-
gen in the fuel  and high  temperature  fixation of
atmospheric nitrogen. In high temperature combus-
tion processes, atmospheric nitrogen and oxygen play
a dominant role in nitrogen oxide formation. Ther-
modynamic equilibrium highly favors the formation
of NO over NO2. Once formed at high temperatures,
the  NO can react with excess oxygen to yield NO2.
However,  the  residence time  usually  available in
combustion equipment  is too short  for more than
5-10  percent of the NO to be oxidized to NO2.
  In  principle,  nitrogen oxide  emissions from  sta-
tionary sources can be controlled by stack gas clean-
ing  methods or  by combustion modification.  Un-
fortunately, however, flue gas treatment methods are

                                                 Table 5
                           ($/Unit of Production)—at Capital Charge Rate of 0.20
                                             (SHORT TERM)
Mortality Harvest
Aggravation of Symptoms in Elderly
Aggravation of Asthma
Acute Irritation Symptoms
Present Standard
24-Hour Threshold, wg/m '
300 TO 400
180 TO 250
Total Suspended
250 TO 300
80 TO 100
No data
8 to 10
8 to 10
No data
                                             (LONG TERM)
Decreased Lung Function of Children
Increased Acute Lower Respiratory Disease
in Families
Increased Prevalence of Chronic Bronchitis
Present Standard
Annual Threshold, ttg/m •
90 TO 100
Total Suspended
80 TO 100
  • There is a growing body of evidence that adverse health effects are related to some form of sulfates. However, inadequate data on  con-
 centrations and compound-specific health effects make highly uncertain even a "best judgment" estimate of a threshold.
 faced  with major  technological and  economic  ob-
 stacles  and at present, no treatment process,  either
 catalytic or scrubbing, appears viable. Thus, combus-
 tion modification  is the only  demonstrated method
 for the control of  nitrogen oxide emissions from  sta-
 tionary fossil  fuel  combustion.
   Control  technology  developments  to date have
 demonstrated  that  flue gas recirculation is the most
 effective combustion control technique  for nitrogen
 oxide  emissions from nitrogen  fixation  and that
 staged combustion  is the most effective technique for
 controlling fuel  nitrogen conversion. The application
 of this  technology  has controlled the nitrogen oxide
 emissions from gas and oil fired  utility boilers  by
 more than 50 percent to a level of 150-250 ppm.
   Reduction in  emissions of up to 80 percent can be
 achieved by the combination  of reducing excess air
 from  50 to 20 percent and recirculating 50 percent
 of volume of  the  flue gas.  The mechanism for  the
 reduction of nitrogen oxide emissions via flue  gas
 recirculation is primarily a result of decreasing flame
 temperature and dilution of the  available oxygen in
 the flame zone. Unfortunately, in large  installations
 the amount of  flue gas recirculation  desired  poses
 major  redesign  problems for existing gas handling
 equipment and ducting.
  In limited short-term testing,  the above  combus-
tion  modifications, combined  with burner  designs
which  prevent burner flame interaction, have also
 resulted in nitrogen oxide reductions of up to 50 per-
 cent in coal fired utility boilers. Experimental burner
 designs have resulted in further reductions of up to
 90 percent.  These burner  design  modifications are
 extremely attractive because they are very inexpen-
 sive and have little or no operating cost penalty.
   In smaller households, commercial and industrial
 combustion sources,  although  the  same design and
 operating principles  apply, very little experimental
 data are available  on the  control of nitrogen oxide
 emissions from  such sources. On a more  long-term
 basis,  work has been initiated on advanced combus-
 tion modification concepts,  such as catalytic burning
 of  natural gas  and coal-derived synthetic fuels  at
 temperatures  near  1400°C.  Ultimately,  utilization
 of such new concepts will allow essentially pollution
 free energy conversion from fossil  fuels.
   Low excess  air  firing of new and existing  units
 costs about S0.82/KW depending upon unit size, age
 and design. This amounts, however, to less than one
 percent of the average $225/KW cost of a new coal
 fired generating  plant.

 Mobile Source Control  of Nitrogen Oxides,
 Hydrocarbons and Carbon Monoxide
  The standards for these motor vehicle related pol-
lutants have  been exceeded in  a number of major
urban areas. In the United States, urban areas repre-
senting nearly 55 percent of the Nation's population

exceed the ambient air quality standards for one or
more of  these pollutants. Table 6 indicates the gen-
eral  range  of  relative  contributions  of  emission
sources in our urban areas.

                     Table  6
          Mix of Emission Sources in the
               Urban Areas—1971
                     Table 7
        Cost Effectiveness of Hydrocarbon
               Control Techniques41
Percent of Total Emissions
Trucks, Buses
& Motorcycles
   Because of  the  fundamental  problems  discussed
earlier in simultaneously controlling nitrogen oxides,
hydrocarbons  and carbon monoxide  from  current
designs of moter vehicle internal  combustion engines,
the strategy in the United States depends on control
of stationary sources  to  achieve nitrogen  oxide air
quality standards.  Mobile source  controls  on the
other hand will be applied to achieve hydrocarbon
(oxidants) and carbon monoxide air quality stand-
ards. These controls may take the form of (1) emis-
sion controls on new and in-use vehicles,  (2) the
reduction of vehicle miles traveled through  the use
of traffic controls, mass transit,  parking taxes,  etc.,
and (3) the  development and implementation of new
power systems having improved emission character-
   In  addition,  uncontrolled   hydrocarbon  vapor
losses from service stations will  make this  source  as
important a contributor  to  hydrocarbon  emissions
as the vehicles they serve.  Translated into  grams/
mile, the hydrocarbon emissions  from service stations
exceed the  1976  new  car  hydrocarbon standards.
Vapor displacement  control techniques  currently
being  developed can partially reduce these emissions
by over 75 percent by 1977.

1. Emission Controls
   The cost  effectiveness of  these control techniques
in terms of pounds of pollutant  controlled  per dollar
expended on control are  described in Tables 7 and
8 for hydrocarbon and  carbon monoxide, respec-
tively. The data in Table 7 show that control tech-
niques designed  to  reduce  hydrocarbon  emissions
from pre-controlled vehicles  and service stations are
clearly the  most  cost-effective.  However,  these are
not  necessarily the most  important in eliminating a
regional air  pollution problem. The figures in paren-
theses in Table 7  show the reductions in total hydro-
carbon emissions  from the  implementation  of  each
control technique.1 These data show that the use of
pre-controlled vehicle retrofits in 1977 (Air Bleed or

(all cars)
Catalyst (1972-1974)
Catalyst (1968-1974)
Air Bleed (pre-1968)
Vacuum Spark Advance
Disconnect (pre-1968)
Gasoline Station Controls
Date of
Program Implementation**
1.64 (3.6 %)
1.79 (3.77%)
1.90 (5.5 %)
5.48 (1.0 %)
6.91 (1.25%)
10.67 (7.1 %)
0.54 (1.5%)
1.31 (3.0%)
1.23 (3.6%)
5.20 (0.5%)
8.36 (0.6%)
11.56 (9.6%)
•Cost-effectiveness increases with the size of the figure.
••The cost-effectiveness of the 1976 hydrocarbon standard is 3.7.

Vacuum Spark Advance  Disconnect)  will  reduce
total hydrocarbon emissions in the air quality region
by only approximately 1 percent. Therefore, the cost-
effectiveness of pre-control vehicle retrofits is very
high, but they achieve  relatively little in the way of
improvement  in  air  quality.  Conversely,  measures
such as inspection/maintenance and catalytic retro-
fits, which  are applicable to controlled vehicles, have
relatively low cost-effectiveness but higher air quality
impact.  Unfortunately, as indicated  earlier  these
catalytic devices may have serious and unacceptable
impact on  sulfate and  on fine particulates. Gasoline
marketing  controls prove to be  both important and
cost-effective  in  eliminating  regional   hydrocarbon
   Finally,  it  should be noted that inspection/main-
tenance  is  a prerequisite for  all retrofit measures
owing to the need to keep the retrofit devices in good
operating  condition. Hence,  it is not  possible in
practice to select an approach such as Vacuum Spark
Advance Disconnect, for example, based on its high
cost-effectiveness  and  implement it  without  inspec-
   The  cost-effectiveness  calculations  for  carbon
monoxide  controls follow a  progression similar to
that for hydrocarbon controls.  Retrofit  devices for
pre-control vehicles again prove to be the most cost-
effective but  measures for controlled vehicles have
the  greatest  impact on air  quality. However, the
carbon monoxide emission reductions (shown in pa-
rentheses)  achieved by those control techniques are
considerably  higher than those  achieved for hydro-
carbon.  Air bleed retrofits, for example, yield a 7.1
percent reduction in total carbon monoxide emissions
in 1977, while air bleed only yielded a  1 percent re-
duction  for hydrocarbons. The relative importance
of carbon monoxide control  techniques is generally
higher  because regional carbon monoxide problems
are  caused primarily by motor vehicles. Again, in-
spection/maintenance is a prerequisite for retrofit.
   » Calculations based on a region with 30 percent stationary lource hydrocarbon contribution such as Philadelphia, Baltimore, and Indianapolis.

                     Table 8
      Cost-Effectveness of Carbon Monoxide

Catalyst (1972-1974)
Catalyst (1968-1974)
Vacuum Spark Advance
Disconnect (pre-1968)
Air Bleed (pre-1968)
Date of
Program Implementation**
17.5 ( 7.7%)
20.0 ( 8.4%)
24.7 (14.5%)
31.8 ( 1.1%)
194.0 ( 7.1%)
8.8 ( 6.3%)
15.2 ( 9.2%)
15.5 (11.8%)
40.9 ( 0.7%)
192.7 ( 4.9%)
•Based on a region with 5 percent stationary source contribution such
as Seattle, Phoenix and Minneapolis,                  .
« "The cost-effectiveness of the 1976 new car carbon monoxide is 32.9.
2. Vehicle Mileage Reduction
  Increasing public awareness of the adverse effects
of the automobile  on the urban environment, and
legislation such  as the Clean Air  Act that has re-
sulted from  this awareness, make it clear that urban
development policies that have encouraged and relied
upon unrestricted use  of the  automobile  must be
changed. Controls  must be  placed  on  automobile
use; transit  must be found to prevent future urban
growth from generating large volumes of  traffic. The
need to reduce urban  area auto use  is no longer at
issue. The problem is how to do so without exces-
sively restricting the mobility  of urban area residents.
  Among the possible approaches to the  solution of
this  problem, increased transit  usage and  quality
seem to  offer the greatest potential for success  over
the long run. Other possible approaches  include in-
creased carpooling, reducing  trip frequencies or trip
lengths, and direct vehicular  restraints (e.g.,  vehicle
free zones).
  Planning  and implementing substantial transit im-
provements  are likely to present severe problems in
the period  1973-77 owing to the difficulties of de-
signing  suitable transit systems  and acquiring the
necessary vehicles. Existing  transit  does not  have
the capacity  to achieve large reductions in auto use.
Most urban transit systems operate at more than 75
percent of  capacity during  periods  of  peak work
travel.  EPA  calculations indicate that with this  level
of capacity  usage,  the  maximum reduction  in  auto
use that  can be achieved by  existing transit fleets is
about 5  percent. Achieving a 10 to  20  percent re-
duction in auto use could require expansions  of cur-
rent transit fleets of at least 50 percent and possibly
over 300 percent. Threefold fleet expansions in many
urban areas  could  exceed the short  run  production
capacity  of the bus manufacturing industry. In addi-
tion to bus production problems, there appear to be
significant short-run planning problems. Most exist-
ing urban area transit plans are  projected to achieve
decreases in auto use  of less than 10 percent.  The
most ambitious transit plan that has  come to EPA's
attention, that for the  Washington  Metro System, is
projected to be capable of achieving a 20-percent re-
duction in  auto use if it were  fully implemented in
1976. In fact, the system will not be completed until
1983. These production and planning problems  sug-
gest that although the potential for reducing auto use
through improved transit is large, it may be unreal-
istic to expect reductions greater than  10 to 20  per-
cent by 1977.
  The cost of bus transit depends on the detailed
characteristics of the  bus system, notably on vehicle
occupancies. Transit  buses cost roughly $1.00  per
mile  to operate compared with $0.07  per mile for
cars. Hence, a transit system that carries roughly 40
riders per vehicle round trip will cost about the same
as the auto. Higher occupancy systems might achieve
net savings of $100 per rider per year.  However,
with low occupancies cost could reach $900 per com-
muter  per  year. There is clearly  a potential  for
achieving  substantial emission  reductions at a  net
cost  savings through increased use of  bus transit.
However, precise cost estimates will not be possible
until  detailed  plans  for  emission-control oriented
transit systems have been developed.
  Car pooling programs appear capable of achieving
net cost savings. A car pool program for the Wash-
ington, D.C. area based on a locator system and in-
creased parking fees has  been  estimated to require
an initial  investment of $1.3  million  and to have
operating  costs of  $0.6 million year. If this  system
achieves a three percent increase in auto occupancies
for peak period downtown work trips, the savings it
achieves in auto operating  costs will  equal the  an-
nualized costs of the system.

3. Mobile  Source Control  Effectiveness
  The projections of emissions reflect reductions in
emissions due to in-use vehicle controls; Federal new
vehicle  emission standards  for automobiles,  trucks,
and  buses; and  Federal new  source  performance
standards for certain categories of stationary sources.
They  also reflect substantial reductions in emissions
from  new   and existing stationary sources due to
present and planned State and local regulations.
   Figure 2 gives a comparison of hydrocarbon  and
carbon  monoxide   ambient air concentrations  now
and that expected in 1977  based on the cumulative
control capability of (1) inspection and maintenance,
(2)  control devices  on new  and  existing vehicles,
(3) 20 percent reduction in auto use, and  (4)  ap-
plications of best available hydrocarbon control tech-
nology to stationary sources.


  The preceding discussion of methods for the  con-
trol of air pollution leads to the following conclusions
concerning  the application of these methods to  con-
trol strategies.







                       CUMULATIVE POPULATION
           .08    .16    .24   .32    .40   .48    .56    .64

                      MAXIMUM CONCENTRATION (PPM)









                                CARBON MONOXIDE
                             18          27         36

                          MAXIMUM CONCENTRATION (PPM)


   1. The achievement  of sulfur oxide  ambient air
 quality improvements is fundamentally dependent on
 the  control of fossil fuel combustion, primarily coal
 and residual oil. In the near term (1975-1985), the
 availability of low sulfur  content fuel and control
 technology limits  reductions in urban  sulfur  oxide
 air quality to levels approximating current standards
 (60-80 micrograms per meter3 on an annual basis).
 Even the achievement of this improvement must de-
 pend on the allocation of limited low sulfur fuel and
 controls to those sources  imposing most heavily on
 ground  level  sulfur  dioxide  concentrations  on  a
 limited regional basis.

   The potentially more  serious  problem  of  sulfate
 control may require widespread  application of much
 more efficient sulfur oxide emission control methods
 than  those  currently  being  developed  and  com-
 mercially introduced. The  apparently very low, safe
 ambient concentrations for this pollutant imply that
 plume dispersion considerations  will not be  appro-
 priate for limiting source control requirements. As  a
 result, until the interrelated questions concerning (a)
 what sulfate compounds impact seriously on health;
 (b) what are  the atmospheric transport and trans-
 formation phenomena which produce  these  com-
 pounds; and (c) what precursors must be controlled
 to what levels are answered it may be very counter-
 productive  to force the  widespread installation  of
 sulfur oxide control technology fundamentally inade-
 quate to  solve this problem at costs  which often ex-
 ceed 25 percent of the  annualized cost  of the con-
 trolled facility.

   2. The widespread  commercial installation and
 proper maintenance of  relatively low cost existing
 particulate control technology can reduce  the emis-
 sion of fine particulate  (less  than 3 micron) from
 industrial processes and  large combustion sources by
 95 percent relative to current practice. This capabil-
 ity can be achieved at an increase of about 1 percent
 to 5 percent in the annualized cost of the controlled
 facility. The achievement  of ambient air concentra-
 tions complying  with probable future  health  stand-
 ards for trace metals and carcinogens will, however,
 require further improvement in controls  particularly
 for combustion sources, either through fuel  pretreat-
 ment or  flue gas conditioning.  In either  case, the
 technologies and energy requirements associated with
 further improvement  imply  a tenfold  increase in
control cost for every one percent further  reduction
in fine particulate  emissions. Further, these  improved
capabilities are at  early stages of development and
will not be commercially available until at least 1980.

   3. Current nitrogen oxide ambient air concentra-
tions  in  the  United  States are generally consistent
with current health  based standards.  As  a result,
emphasis is placed on a strategy of maintaining these
levels. Combustion  modification techniques capable
of reducing nitrogen oxide emissions by at least 50
percent  from all classes  of  stationary  combustion
sources  appear  to  be either commercially available
or in an advanced state of development. These tech-
niques appear capable of at least maintaining current
ambient air quality  levels  for the foreseeable  future
if  adequate incentives for  commercial  implementa-
tion are applied. The costs of these combustion modi-
fication techniques  are about one percent of the an-
nualized cost of industrial  and utility  combustion
facilities, but may be as much as 10 percent  of the
cost of smaller space heating equipment.
   4.  The  control  of hydrocarbons,  oxidants  and
carbon  monoxide is  primarily  a function of mobile
source  control  strategies.  If fully  implemented in
1977, mobile source emission control techniques can
produce  a 20-percent reduction in hydrocarbon emis-
sions and a 40-percent reduction in carbon monoxide
emissions. This control capability will increase motor
vehicle cost by about 5 percent. While these emission
reductions  and the  corresponding urban ambient air
quality  improvements which result  are significant,
they are not adequate to universally achieve ambient
air quality standards for oxidants and  carbon mo-
noxide.  As a result,  urban areas encompassing more
than 40  million  people in  the United States will  re-
quire at least 10 percent  reductions in the vehicle
miles travelled in addition to direct emission control
techniques. Reductions of this magnitude will require
expansion of urban  mass transit capabilities extend-
ing past  1980 and incentives to shift urban commuter
patterns  to mass transit.

 I. Nationwide Inventory of Air Pollutant Emissions 1970,
   U.S. Environmental Protection Agency,  October 1972*.
 2. Control  Techniques for  Paniculate  Air  Pollutants
   AP-51,  National Air  Pollution Control Administra-
   tion, January 1969.
 3. Control  Techniques for Carbon Monoxide,  Nitrogen
   Oxide,  and  Hydrocarbon  Emissions  from  Mobile
   Sources  AP-66, National  Air Pollution Control  Ad-
   ministration, March 1970.
 4. Control  Techniques for Nitrogen  Oxides from  Sta-
   tionary Sources AP-67, National Air Pollution Control
   Administration, March  1970.
 5. Control Techniques  for Hydrocarbon and Organic  Sol-
   vent Emissions from Stationary Sources  AP-68,  Na-
   tional Air Pollution Control Administration,  March

 6. Abatement of  Particulate  Emissions  from  Stationary
   Sources COPAC-5,  National Academy of Engineering,

 7. Abatement of  Nitrogen Oxide  Emissions from  Sta-
   tionary Sources COPAC-4, National Academy of En-
   gineering, 1972   .
 8. Feasibility  of Emission  Standards  Based on Particle
   Size, U.S.  Environmental Protection Agency Contract
   68-01-0428,  Midwest   Research Institute, November

 9. A  Survey  of  Emissions and Controls for Hazardous
   and Other Pollutants, EPA-R4-73-021, U.S. Environ-
   mental  Protection  Agency, February 1973.

10. Proceedings-Symposium on Control of Fine Paniculate
   Emissions from Industrial  Sources, U.S.-U.S.S.R. Work-
   ing  Group  Stationary Source  Air  Pollution  Control
   Technology, lanuary 1974.
11. The Economics of  Clean  Air, Report of the Adminis-
   trator of the  Environmental  Protection  Agency to the
   Congress of the  United  States, Document  No. 92-6,
    March 1971.
12. Environmental   Considerations   in   Future   Energy
    Growth,  Vol. I,  II, and  IV, U.S. Environmental Pro-
    tection Agency, Office of Research and Development,
    April 1973.
13. National Public Hearings on Power Plant Compliance
    with Sulfur Oxide  Air Pollution Regulations, U.S. En-
    vironmental Protection Agency, January 1974.
14 Proceedings  of  Symposium on  Multiple-Source  Urban
   Diffusion  Models AP-86, U.S. Environmental Protec-
   tion Agency, 1970.
15. Some  General  Economic Considerations of Flue Gas
   Scrubbing for Utilities,  U.S.  Environmental Protection
   Agency, Control Systems  Laboratory,  October  1972.
16. Pollution  Control  and  Energy Needs, Advances  in
   Chemistry Series 127, Chapter 5-T6, Effect of Desul-
    furization Methods on Ambient Air Quality, The Amer-
    ican Chemical  Society, September 1973.
17.  The Clean  Air Act  and Transportation Controls: An
    EPA  White  Paper, U.S.  Environmental Protection
    Agency, Office  of Air  and  Water  Programs,  August

Development of Maximum  Permissible Environmental  Loading
                                        Mark A. Pisano *
  Ideally the desired level of water quality improve-
ment and the date it will be achieved would be estab-
lished  by taking into consideration the  costs  of
achieving various levels of improvement and select-
ing the level of control where the costs equate  with
the benefits.  To this date the water pollution control
program  in  the  United States has not  followed a
strategy establishing a control level that in all cases
would balance costs of control options with the bene-
fits of reduced health and ecological damage.
  In the 1948 Federal Water Pollution Control Act
the United States established an  enforcement  con-
ference  procedure whereby control levels  on  indi-
vidual dischargers were established by allocating pol-
lutant load reductions in proportion to the reduction
required to meet locally established water use (bene-
fit) determinations.  The process did not result in  an
adequate level of water quality improvement. Since
that time there have been successive changes in na-
tional laws,  most notably the Clean Water Restora-
tion Act of  1966. This Act introduced the concept
that the level of water quality to be achieved would
be  determined not  by a  local enforcement confer-
ence but rather national water quality standards were
to be jointly established  by States and the Federal
Government. These efforts, however, also  were not
found satisfactory, owing partially to the complexity
of the  water pollution problem and the difficulty in
implementing the regulatory machinery.  Implement-
ing a national pollution control program involves a
large number of organizations and institutions, many
of which have competing goals and objectives. To the
extent  that the implementation does not specify the
decision  rules and the target  outcome of such a
process, the  resolution of these competing  interests
often fails. While national/state standards were  es-
tablished, the implementation of these standards was
conducted on a case by  case basis. The actual  re-
quirements levied against  dischargers became unclear
and the schedules for achieving the standards slipped.
  In  1972,  new legislation was enacted which at-
tempted to solve  the  problems of previous  efforts.
This paper describes the method of establishing water
quality targets and  dates of their achievement and
the design of the program for meeting these targets.


   Previous papers have dealt with stress of pollutants
on  man and  on ecosystems. These discussions con-
tained, to the extent possible,  an assessment of the
risks  and  costs associated with stresses on the eco-
system, i-e-, damage functions.  From these functions
target maximum permissible species stress could  be
established.  Another set of papers concentrated  on
the control  methods that  are  employed  to achieve
pollution control. These discussions also included the
costs  associated with  these controls. Depending  on
the costs  of these  control  methods  and the time
period required to implement them, a strategy speci-
fying  the  level and time period of implementation
of the Maximum Permissible Environmental  Load-
ing (MPEL) could be established.
   The regulatory strategy in water is not based  on
such  a balance where the costs  of the level of control
would equate with benefits. Rather the central thrust
in the water program  is that control measures them-
selves will establish the MPEL. Successive improve-
ments in technology will be required over time, until
a  target  of  zero discharge is  achieved. Thus, to a
large  extent, the "raison d'etre"  of the program is a
reliance on  the advancing capability of technology.
The  program is based on an assumption that any
discharge  to  water would upset the  natural integrity
of  water,  therefore any increase in the removal of
pollutants is desirable.
   The strategy does recognize that a uniform appli-
cation of technology  might  not result in an  appro-
priate level of controls to protect  health and eco-
systems in every case. Thus, the concept of a control
level  dependent on the instream criteria which sup-
port  the intended use of each  specific body of water
  •Director, Water Planning Division, U.S. Environmental Protection Agency

is still maintained. If this water quality standard can-
not be met by the requisite technology standard for
the period, then a higher level  of technology  could
be required. Also, if over time  it is found that it is
not technologically feasible and/or it is economically
infeasible to move to zero discharge then the  water
quality standard can be used to determine a less strict
level of control than zero discharge.
   It  should be  noted,  however,  that  successively
higher levels of technological controls where  feasible
will be required even though the water quality stand-
ards might be achieved with less stringent controls;
in which  case the cost of control could be  greater
than the apparent benefits to society. This apparent
inefficiency is permitted based on the assumption that
if a pollutant can be removed  at "reasonable" cost
then it will be. Also,  because  of our historical in-
ability to  adequately equate cost of removing pol-
lutants to  the benefits achieved  by cleaner water, a
second best solution of at least  requiring what tech-
nology can economically achieve regardless of  the
cost/benefit calculus has been an important  part of
the U.S. regulatory strategy.
   There are two parts to establishing  the MPEL in
the U.S. The first is effluent guidelines which  are like
performance specifications as to  what technology can
do and when the technology can be  implemented.
The second is the water quality standard which serves
as a guide or check point as  to  the  adequacy of

Determining Effluent Guidelines (Table  1
provides  a summary of these requirements.)
   By 1977 all dischargers will be required as  a  mini-
mum   to  install  best  level technology—secondary
treatment for municipalities and best practical con-
trol technology  for  industries.   The key  concept is
that by 1977, every facility of a given type and size
must have its pollution release equivalent to all other
facilities of the same type  and size. To  the  extent
possible, the objective is  to develop guidelines  that
may be applied to individual  dischargers without
the necessity of treating each discharger as a unique
situation.  Because of the heterogenity of dischargers,
industrial  categories have been sub-categorized ac-
cording to their age and  size, raw materials, manu-
facturing  processes,  products  produced,  available
treatment technology, energy requirements and costs.
   Within  each category the effluent amount is based
on the known performance of the better performers
having  well designed and  well operated treatment
systems. A  key consideration in the  determination
of the  effluent  limit for the category is a balancing
of total costs of treatment, including capital costs and
operation  and maintenance, against the  effluent re-
duction benefits achieved. The decision rule is to set
the limit at the point where the marginal cost of re-
moving additional amounts of pollutants significantly
increases.  For example, as shown in  Figure  1, the
incremental cost of removing additional amounts of
BOD increases rapidly beyond the secondary treat-
ment level for municipal discharges. This was a major
reason for establishing the base level technology for
municipal dischargers as secondary treatment and  is
expressed as shown in Table 2.
   For  industrial categories the  removal levels  and
the parameters considered are not uniform between
categories. These  variations are shown in  Table  3
which presents summary data for six effluent guide-
lines. Because of technological advances in some in-
dustries, the cost/effluent reduction benefit test re-
sults in a  base  removal  level of zero discharge, e.g.,
insulation fiberglass.
                     Table 1, Principal Statutory Considerations for Effluent Guidelines
Statutory Basis
Best Practicable Control
Technology Currently
[Existing Sources]
Best Available Tech-
nology Economically
[Existing Sources]
Standards of Performance
Best Available Demon-
strated Control Tech-
[New Sources]
General Description
1. Achieve by 1977.
2. Generally average of best exist-
ing performance; high confidence
in engineering viability.
3. Where treatment uniformly in-
adequate a higher degree of treat-
ment may be required if practicable
[compare existing treatment of
similar wastes].
1. Achieve by 1983.
2. Generally best existing per-
formance but may include tech-
nology which is capable of being
designed, though not yet in place;
further development work could
be required.
1. Achieved by sources for which
"construction" commences after
proposal of regulations.
2. Generally same considerations
as for '83; more critical analysis of
present availability.
Process Changes
Normally does not
emphasize in-process con-
trols, except where pres-
ently commonly
Emphasizes both in-
process and end-of-
process control.
Emphasizes process
Balancing of total cost of
treatment against effluent
reduction benefits.
Cost considered relative
to broad test of reason-
Cost considered relative
to broad test of reason-

       Figure  1. Typical Values, Biological
             Oxygen Demand (BOD)

Secondary (Hi-Rate)
(Conventional +)
Two Stage Nitrification
Advanced Waste
Treatment +






      Table 2. Base Level Technology Limits
Biochemical Oxygen
Demand (5-day)
Suspended Solids
Fecal Coliform
number/ 100 ml.
Monthly Monthly
Average Average
30 45
30 45
200 400
within limits
of 6.0-9.0
  By 1983 all industrial dischargers will be required
to install best available technology (BAT). The level
of control will  be based  on best performer  of a
category and will not include just end-of-pipe treat-
ment, but process changes and product modifications
as well.  In some cases BAT may reflect  prototype
technology not yet demonstrated  to be practicable.
The objective is to develop technologies with higher
removal rates,  including some calling  for "no dis-
  In setting the BAT limits,  sub-categorization will
also be employed. Within these categories costs will
be considered relative to a broad test of reasonable-
ness which includes  the feasibility and cost of  the
technology, i.e., can the control be put in place at a
cost that is not prohibitive.  The economic test will
not  necessarily  be the cost/amount  of effluent  re-
  For municipal dischargers the 1983 requirement is
not similar to the industrial standard. Instead of in-
creasing the amount of reductions to be obtained by
requiring more advance technologies, municipalities
are required to consider alternative waste water man-
agement  techniques  and choose the most cost-effec-
tive and environmentally advantageous alternative.
Treatment and reuse, and land treatment of wastes,
both of which provide either zero discharge or high
levels of treatment,  must  be among the alternatives
considered.  The environmental and  cost-effective
tests may demonstrate that a higher level of removal
above base  level technology or an alternative man-
agement  technique  may be required. The test is  not
uniform; rather a case by case assessment must be

Setting  Water Quality Standards
   Water quality standards are established jointly by
the States  and Federal government.  Each of these
standards consists of a designated use criterion repre-
senting the  acceptable limits of pollutants in  receiv-
ing waters dedicated to that use. These criteria are
based on the latest  scientific knowledge of the effects
of  pollutants  on human health and biological com-
munities. With respect to uses, the U.S. has set as a
goal that where  attainable  all waters will be swim-
mable and will provide for the protection and propa-
gation of fish, shellfish  and wildlife by 1983. The
phrase "where attainable"  recognizes that naturally
occurring  conditions, or  uncontrollable  non-point
source pollution, could result in a failure to meet the
 1983 goal. Table 4  provides an example of the 1983
use classification and criteria that are likely to be
needed to  support  these uses. The  criteria  in  this
table are changing  as new  data are acquired. The
process for setting these standards is to first establish
the intended use of the water body and the intended
biological  activity desired.  For these uses and bio-
logical protection  the  appropriate  criteria  (MFC)
 are defined, for example, temperature in a water body
                                       Table 3. BPT for Industry

Meat Processing


Flat Glass


No. of Plants
1200-4800 very
small plants

3500 large


Estimated Percentage
Raw Waste Load
Reduction Expected
• —




97- 99




Other Pollutant
Parameters Controlled
pH, Temperature
pH, Temperature, COD, TDS,
Phosphorus, Nitrogen, Oil and
Grease, Chlorides
COD, Oil
COD, Chlorides, Nitrogen,
Phosphorus, Fecal Coliform
Oil, COD, pH, Phosphorus, TDS,
Phenols, COD, TDS, Oil and
Grease, pH, Temperature,

                   Table 4. Example Water Quality Criteria Summary by Use Classification

Use Class.
Class A
water ski-
ing, etc.)

Class B
Species of
Life and

Shall not
exceed a
mean of
200 fecal
per 100 ml.

Shall not
exceed a
mean of
10,000 total
coliform or
2000 fecal
per 100 ml.
(Fecal coli-
form counts
are pre-

Not less
than 5 mg/
1. Class B
levels also

Not less
than 5 mg/
1 (except
for 4 mg/1
for short
periods of
time within
a 24-hour
Not less
than 6 mg/
1 in trout
waters. Not
less than 5
mg/1 in

90'F Max-
imum. Class
levels also

Cold Water
50°F rise.
Max. of

(Bass etc.)
5°P rise in
j r i toe 111
3 °F rise in
Max. 90'F.


ion concen-
trations ex-
pressed as
pH shall be
between 6.5
and 8.3.

ion concen-
trations ex-
pressed as
pH shall be
between 6.0
and 9.0.

Shall not
exceed 500
mg/1 or
above that
tic of nat-
ural condi-
tion (which-
ever is less).
Shall not
exceed one-
third above
that charac-
teristic of
natural con-

and Odor
None in
that will in-
terfere with
water con-
tact use.

Shall con-
tain no sub-
which will
render any
tastes to fish
flesh or in
any other
way make
fish inedible.

Class B lev-
els apply.

Cold Water
Total dis-
solved gas
pressure not
to exceed
110 percent
of existing

Color and
• «»»»»«ij
Secchi disc
visible at
min. depth
of 1 meter.

10 JU

50 JU

Secchi disc/
visible at
depth of 1

 will vary according to the level of biological protec-
 tion. Finally, the flow regime defining  the critical
 periods when standards  must be met are  specified,
 for example, 7-day, 10-year low flow in humid areas,
 5-day, 5-year low flow in arid areas, etc.


   The immediate task of  the U.S.  regulatory pro-
 gram is the classification of all hydrologic segments.
 Where the application of best practicable technology
 for industries and secondary treatment for municipal
 plants will result in  meeting  1977  water  quality
 standards, the  segment  will  be  categorized as  an
 effluent guidelines limited segment. Where  this con-
 trol  technology  will  be  insufficient  to achieve the
 necessary level of water quality, the segment will be
 classified  as a water quality limited segment. Where
 there is  significant doubt,  a segment will  be  con-
 sidered as a water quality limited segment,  subject
 to a later reclassification.
   About half of the segments are so heavily polluted
 the dischargers  located on them  will be required to
go beyond  1977-level pollution  controls to enable
water quality standards to be met:
   Effluent guidelines limited segments       1515
   Water quality  limited segments            1588
  Total segments identified by States
 Short Run Control Program

   All dischargers must obtain permits which dictate
 the amount of discharge that is allowed to  be  dis-
 charged from an individual plant or municipality, and
 a  schedule  of remedial measures, including  an en-
 forceable sequence  of actions or operations  leading
 to compliance with  the effluent limitation. Failure to
 comply with an interim or final requirement in the
 permit constitutes a violation of the permit, for which
 the permit holder could be fined up to $25,000 per

 Effluent Segments

   The effluent conditions for dischargers in effluent
 segments are based  on the effluent guidelines. A hy-
 pothetical  example  will  be  presented to  illustrate
 the application of these guidelines. A proven  and
 feasible technology  for treatment of pickle-packer
 wastes is an "activated sludge treatment plant";  this
 is  essentially just like a municipal  sewage  treatment
 plant, and is a good treatment  technology for food-
processing wastes. Furthermore, let us  suppose that
20 percent of the dill  pickle-packers already use  this
treatment method, and that the average performance
of the best-run treatment facilities results in 1 pound
of BOD  (oxygen-demanding  organic  wastes), 2
pounds of suspended solids, and zero (no)-discharge

of dill seeds or  garlic cloves  per 1,000  pecks of
pickles packed.  Thus  our final effluent limitations
might well be stated as shown in Table 5.

       Table 5. Hypothetical Effluent Limits

            INDUSTRY:  Pickle-Packers
            SUBCATEGORY: Dill Pickles
Dill Seeds
Garlic Seeds
Effluent Limitations
1 pound
2 pounds
Zero Discharge
Zero Discharge
Per Unit of
Thousand pecks of
pickles packed
Thousand pecks of
pickles packed
(No units needed)
(No units needed)
   Given this  sort  of  effluent  limitation, we could
easily calculate the pounds of  BOD  and suspended
solids a  dill pickle-packer of any size  could be al-
lowed  to release  and still be consistent  with  this
standard. For example,  a pickle-packer processing
5,000 pecks of dill pickles  per  5-day week would
receive a permit allowing release up to 5 pounds  of
BOD and 10 pounds of suspended solids per week,
or  1  pound  of  BOD  and 2 pounds of suspended
solids per day, from the dill pickle part of his facility.
The permit would also specify the final date when the
packer would be required to  achieve this level of dis-
charge,   and interim  compliance  milestones,  e.g.,
begin construction.

Water Quality Segment Analysis
   Violations of standards in water quality segments
could be caused either by point sources which must
be subjected  to controls beyond best  practicable
treatment (BPT)/secondary treatment or  by  non-
point sources which must be controlled. The imple-
mentation program in the U.S. currently concentrates
on point source discharges. Ideally the water quality
segment analysis would determine the most effective
allocation of waste leads  between all  point and  non-
point discharges. In the  short run, however, if the
contribution of  the point source dischargers cannot
be distinguished  from   the nonpoint  source  dis-
chargers, then  base level technology  will be applied
to the point source discharge.
   The analysis  would be completed for each para-
meter which is in violation of water quality standards.
The analytical process for performing the  load  al-
location for these parameters is outlined in Figure 2.
Each source contributing that parameter to  the seg-
ment should be identified and alternative  remedial
measures considered.  The  final  treatment/control
strategy  for the segment should reflect a combination
of control methods which  will  meet  water quality
standards for all water quality parameters.
   As noted in  Figure 2, modeling is generally the
appropriate method of ascertaining  total maximum
daily  loads and determining  the  effects of the pro-
posed alternative abatement strategies.
  Water quality  analysis  through modeling enables
planners to predict water quality under adjusted con-
ditions  of  flow,  temperature and pollutant  loads.
Hence,  it provides a basis for  load  allocation  and
effluent  reduction determinations.
  Water bodies may be categorized in one of three
categories: flowing streams, estuaries, and lakes and
impoundments. Dominant transport mechanisms dif-
fer in each category; hence, different  modeling tech-
niques  are  appropriate   for  different  categories.
Further, the degree  of sophistication  of technique
within each water body category may also  vary ac-
cording to conditions in the water.
  The  water  quality analysis  and  prediction  de-
veloped  by any model can  only  approximate  the
actual water  quality  which  will occur  under  the
various suggested hypotheses. These assumptions will
never be entirely correct for the distinct  water body
being analyzed. Hence, remedial measures  (effluent
reductions) based on the model predictions will not
result in water quality exactly  as  predicted  by the
model.  Since  unnecessarily stringent measures  may
result in costly overbuilding and inadequate meas-
ures may fail to protect  the  aquatic ecosystem and
achieve  established water quality goals, model selec-
tion must consider the degree of risk to be accepted.
   Table 6 summarizes the criteria for the selection
of  an analytical technique.  The table lists  criteria
for each of the four levels of complexity. For  each
level of complexity, the  table presents the type of
problems and water bodies for which the level is
appropriate, the planning characteristics (complexity
and risk)  associated with that  level and  the  time
required for a study.
   •  Type A simplified analysis generally has  rela-
      tively few waste sources and an assumption is
      made that there are no changes in waste loading
      and hydrology with time (steady state).
   •  Type B  steady  state linear kinetics  has  several
      sources which  have  overlapping stream  effects,
      steady state conditions still hold, i.e., no  change
      in waste loading and hydrology.
   •  Type C  transient linear kinetics has multiple
      sources which  have  overlapping stream  effects,
      waste loading and hydrology vary linearly with
      time, e.g., storm  event diurnal  variations and
      variable waste  discharges. Type D time variable
      non-linear kinetics has multiple sources which
      have overlapping two-dimensional stream,  lake,
      or estuary effects. The internal mixing  process
      represents a major problem.
   Once a model is selected a set of worst conditions
 is assumed  and streamflows and temperatures are
 fixed to arrive at a waste load allocation. By suc-
 cessive  approximations of waste inputs, the maxi-
 mum allowable  effluent  levels  for each of the dis-

                                     DO DEFICIT
                                   DO STANDARDS?
                              (INCLUDING BACKGOUND)
           AS GIVEN BY
           LEVEL UNTIL
                 "FIGURE 2b.
chargers can be established to meet the water quality
standard for a particular constituent. The goal may
consider a reserve margin for accommodating future
projected loads or uncontrolled natural background
levels. The total allocation for a segment is the sum-
mation of all individual allocations of the component
  In a  system with a  large number of pollutant
          sources the chance of each discharge being at its ex-
          treme allocated stress value  simultaneously with  all
          of the other sources and with the rare low  design
          streamflow is statistically small. To issue permits
          based on the daily averages  would be unnecessarily
          restrictive. It is  reasonable  therefore to  define the
          permitted waste load for each discharger as a weekly
          average waste discharge.

                           INCREMENT EACH
                           DISCHARGER BY
                           DISCRETE LEVEL
                         MAXIMUM ALLOWABLE
                           DISCHARGER LOAD
                              FACTOR  (R)
                             ALLOCATION =
                             R x MAXIMUM
                              CHECK FOR
                             UPPER BOUND

                                  Table 6. Criteria for Selection of Techniques
    Model Complexity
Water Quality Problems
     and Variable
     Water Body
                         Time Required
                           for Study
 Simplified analysis

 (Type A)
D.O.  (carbon and  ni-  One-dimensional
trogen)                streams  and  estuaries
                      (completely mixed).
                                            a.  Low risk of capital
                                            and/or  environmental
                                            quality degradation.
                                            b.  No alternate strate-
                                            gies  and  control op-
                                            tions available.
                                            Days to weeks.
 Steady state linear

 (Type B)
a. D.O   (carbon  and  One  or  two-dimen-
nitrogen), temperature  sional  streams,  estua-
and nonpoint source.    ries, rivers, lakes.
b. Anticipated  or  ex-
isting  water
                      a.  Low  to  moderate  2 to 9 months.
                      risk of capital and en-
                      vironmental quality de-
                      b.  Alternative   strate-
                      gies  and  control  op-
                      tions  must be availa-
 Transient linear kinetics

a. Time varying  D.O.,
nonpoint source  anal-
ysis, and temperature.
Simple  eutrophication
analysis.  Full   storm
water overflow  analy-
b. Water quality  prob-
Rivers, lakes and estu-
aries.  One  or  two-di-
a. Moderate  to  high
risk of capital and en-
vironmental quality de-
b. Alternative   strate-
gies  and control  op-
tions  must  be availa-
                                                                  6 to 24 months.
 Time variable non-linear
 kinetics analysis

 (Type D*)
a.  Detailed eutrophica-
tion analysis, etc.
b.  Water quality prob-
c.  High growth of area
All bodies of water.
                                            a. High risk of capital
                                            and/or  environmental
                                            quality degradation.
                                            b. Alternative   strate-
                                            gies  and control must
                                            be available.
                      12 to 36 months.
 •Type D studies are to be performed only in very complex situations and should be regarded as research efforts,
   Exceptions to  this may be desirable when one or
 two dischargers dominate the combined load or when
 relatively large loads occur within short time periods
 (as opposed  to  reasonably steady day-to-day  dis-
 charges). If there are only one or two dischargers in
 a segment, the probability of all peak loads occurring
 simultaneously is  greatly increased. If the  environ-
 mental risk  is high,  shock loads  of some  constitu-
 ents should  be restricted. For such cases,  permits
 specified on  a shorter  term such  as  a daily mean
 rather than  a weekly average would be  prudent.

 Long Run Control Program

   On  some  water quality segments the total loading
 discharged into the stream may be such that the best
 known technology  may  not  be adequate to achieve
 the water quality standard when applied to existing
 point source discharges. On the other hand, the cause
 of the problem may be a non-point source problem.
 In  many urban areas the control problem might be
 urban  run-off or combined sanitary and storm wastes
 which  bypass  the treatment  plant during periods of
high flow. Construction of roads, housing and other
facilities also creates problems  of increased sediment
                                    Where  serious  water quality  control  problems
                                 exist,  areawide waste water  planning and manage-
                                 ment  agencies  are being established. The agencies
                                 will develop control strategies that look not  just at
                                 technology solutions,  such as  treatment facilities, but
                                 also will examine land use  and land management
                                 alternatives.  In many of these situations,  altering or
                                 controlling future  sources of  pollution might  be the
                                 only feasible solution.  This  might involve controls
                                 on the amount of growth that could occur in an area,
                                 or controlling  where  new facilities  could locate. Or
                                 the solution might  involve affecting the way in which
                                 land is  used,  e.g., the design of residential  subdi-

                                    In  establishing  the  levels  of controls  for  dis-
                                 chargers  in  water quality  segments  where  higher
                                 levels  than BAT are required, consideration  of the
                                 social  and economic costs and benefits of alternative
                                 control strategies is required. The control strategies
                                 could  range from technological solutions to land use
                                 solutions. If there are no feasible solutions with costs
                                 equal  to  the  benefits  then  the goal  of swimmable
                                 waters and a balanced ecosystem may need to be re-


  Dr. Izrael pointed out that there are three methods
of setting the MPEL:
   • one that is ecologically desirable;
   • one that reflects public health;
   • one that we can technically achieve.
In  the United  States we are currently following a
mixture  of these approaches  with  an emphasis  on
doing what is  technologically feasible,  but not be-
cause a mixed  strategy is necessarily better. Rather,
our philosophy is that if it can be done, then do it,
even  if  technology over-protects or  under-protects
public health and ecological objectives. As a scientific
community we must find out what information the
administrative process  needs in order to fully imple-
ment a mixed strategy that balances all three of the
limiting  conditions  for establishing the MPEL.  To
achieve this balance we need to improve our knowl-
edge  concerning  concentrations  of  pollutants  and
their health and/or ecological effects. We also need
to further our understanding of the frontiers of tech-
   We also need to improve our ability to make better
decisions  on specific  control requirements for indi-
vidual dischargers. We need to  improve our  ability
to make waste load allocations. It does not help the
regulatory program if we have complete information
on what the water quality criteria should be, but we
cannot  monitor or determine the control measures
that are to be levied against point  and non-point
sources to achieve these criteria. A possible effort of
future exchange could be improving  the monitoring
and analytical techniques used to relate water quality
criteria to required control programs within a water

   The Effect of Polluting a Biogeocoenosis With  Strontium  90
           on  a  Population of Mammals and the Zoocoenosis

                      V. Ye. Sokolov, A. I. Il'yenko, D. A. Krivolutskiy *
  Industrial pollution  of the biosphere  significantly
affects the  ecology of the  organisms that populate
the biogeocoenosis. This effect may be expressed by
disruption of the biological processes taking place in
the population, as well as by change in the relation-
ships between organisms, and between organisms and
the physicochemical factors of the habitat. Chemical
pollution of the  biogeocoenosis  accumulated by its
components can  be considered to be a  new abiotic
factor for animals that acts on the population, com-
munity, and on the biogeocoenosis as a whole, along
with the usual environmental factors of the habitat
in which the organisms live.
  The experimental introduction into the biogecoe-
nosis  of radioactive elements such as strontium  90,
the chemical analog  of Ca,  for  example, which is
distinguished by the   simplicity  of determining  the
quantitative distribution of the isotope in a  popula-
tion, and  among the  components of the biogeocoe-
nosis  by radiometric   and  dosimetric methods, pro-
vides  a way to establish the most vulnerable links
in the animal ecology in the  face of chemical pollu-
tion.  The disruptions discovered in the ecology of
populations and  zoocoenosis  in a biogeocoenosis
polluted by strontium 90  can, possibly, serve as  a
model and  be valid  for  many  types  of chemical
   The question  of the combined complex effect on
animals of certain factors  man  has introduced into
natural biogeocoenoses is being discussed widely to-
day. We will devote special attention in our report to
the effect that factors of the habitat which are normal
for the  natural  populations  have against  a back-
ground of radioactive pollution of the biogeocoenosis.
   The work was performed in two open-air cages,
each  with an area of  one  hectare. One of the cages
was polluted with strontium 90 at a pollution density
of from  1.8 to 3.4 millicuries/m-. The other cage,
which we shall conventionally call the "clean cage,"
had a background pollution consisting of  artificial
radioisotopes on a global level.
  The cages were populated by two species  of ro-
dents:  field  (Microtus  agrestis) and  northern red-
backed  (Clethrionomys rutilus) voles. The  beasts
were trapped in the cages once a  month, and were
marked by amputating  the toes in such a way that
each zooid had its own  individual number. Blood for
study was drawn simultaneously, and part of the tail
was severed for radiometric analysis.
  Systematic observation of the tagged population
yielded  much data, and  these are included  in the
The effect of polluting a biogeocoenosis with
strontium 90 on the age structure of a popu-
lation and the course of the biological cycles

   The populations of the two species of voles kept
under the conditions that prevailed in the open-air
cage where the  experimental section had pollution
levels of 1.8-3.4 millicuries/m2,  showed differences
in  the  degree  of  accumulation  of strontium 90
-yttrium 90 in the skeleton (Il'yenko, 1967;  Soko-
lov, Il'yenko,  1969). The concentration of isotopes
in the boney tissue of the  field (Microtus agrestis)
and northern redbacked  (Clethrionomys  rutilus)
voles was 0.11 ± 0.001,  and 0.5 ± 0.001|ucuries/g,
respectively, and the dose rate from the isotopes de-
posited in the skeleton was 0.77, and 0.35 rad/day
for the bone marrow. The  survival of the overwin-
tered populations of these  species of voles, that is
for those who lived in the cage for more than a year,
was not identical under these conditions  (Figure 1).
Evidently because of differences in the dose of ir-
radiation from the isotopes  deposited in the skeleton,
the mortality was higher,  and the overwintered popu-
lation died off more rapidly, among the population of
field voles, than was the case in the clean area. This
pattern was less pronounced among the population
of northern redbacked voles. The mortality among
 the population of field voles during the winter in the
   •A. N. Severtsov Institute of Evolutionary Morphology and Animal Ecology of the Academy of Sciences of the USSR, Moscow





- *" °, FIELD
. \\
• v
• \\
\ Xo

• V
Experimental — ^\

i i i i i
\— - Control
N^ \
>v \
\. \
X. N
	 1 	 1 ^«
      4    5   678   9  10 11

 polluted and clean  cages  was 95.2% and 50%, re-
 spectively. It is possible that differences in the radio-
 sensitivities of these  species  also affected the mor-
 tality rate.  Thus, the LD5o/3o for the northern red-
 backed voles is 960 rads, and is somewhere around
 600  rads for field voles. The life span of field voles
 that  survived the winter in  the populations under
 study differed little, and those  differences  found
 were statistically unreliable. The mean life span for
 beasts in the polluted section, and in the control,
 was  11.6 ± 0.8, and 12.5 ± .08 months,  respec-
  The populations  of small  mammals receive dif-
 ferent doses of ionizing irradiation at different sea-
sons  of the year. The result is that the survival rate
of the groups of beasts in the population in the pol-
luted area  is  unequal (Figure 2)  among the field
voles born during  different  reproduction  periods.
Most of the beasts born at the beginning of the sum-
mer do not  live until the spring of the next year. The




            Control Group
                                                                Polluted Territory




Animals surviving to
second half of winter
      Animals born at the beginning of summer

 I	I  Born at the end of summer


number of animals born at the end of a reproduction
period was  98%  of  the  spring  population. Only
half of the animals  born at the end of the summer
survive the winter and live until the  spring of the
next year. Few deaths are recorded among the con-
trol population, however, The structure of the rodent
population in the polluted territory changes substan-
tially as a result.

  Disruption in the reproduction rate was established
during the study of reproduction patterns in the
rodent population in the experimental sections pol-
luted  with  strontium 90 at levels of from 140 to
1200  millicuries/m2. The ovum mortality rate before
implantation increased with increase in the strontium
90  - yttrium 90 concentration in the  skeletons of
long-tailed mice  (Apodemus sylvaticus) (Figure 3).
The sharp  increase  in the  ovum  mortality   rate,
greater than that in the control by a factor of 3, was
observed when the concentration of strontium 90 —
yttrium 90 in the animals' bone marrow was 0.003
/icurie/g. The number of embryos in  the females
among the population  of northern redbacked voles
decreased with an increase in the concentration of
isotopes in the skeleton (Figure 4). The study of the
biological patterns found among isolated populations
under open-cage confinement revealed that reproduc-
tion among the field  vole population ended a month
earlier than among  the control population of this
species confined under analogous conditions, but on
unpolluted territory.
The Effect of Climatic Factors

  The action of ionizing radiation on a population
is particularly  strong during the extremal period  of
the  existence of  small mammals, when such action
intensifies the  action of  all the unfavorable factors.
This is why the mortality rate for the rodent popula-
tion is particularly high in the winter time in an area
polluted by strontium 90.

  The rodent population does  not renew  itself  in
the winter time, something that is characteristic  of
other seasons of the year, and is the result  of these
animals'  reproduction. The population dies off rap-
idly during this period, the result  of the effects of a
number of unfavorable climatic factors. The  most
critical times in the  lives of the rodents are the peri-
ods of establishment of the permanent snow cover,
and of the melting of the snow in the spring. Winter
weather conditions are a lesser cause of death among
small  mammals  and  act  differently  on  different

                                        APODEMUS SYLVATICUS
                         Back-    5x10~4  1 x10~3  3x 10~3 9x10~32x10~* 6x10~2

                                                                      H CURIES/g
                             IN A POPULATION OF  LONG-TAILED MICE

i    e
            Concentration in skeleton, wcuries/g

               REDBACKED VOLES AS A
               FUNCTION OF THE CONCEN-
               TRATION OF STRONTIUM 90 -
               YTTRIUM 90 IN  THE SKELE-
               TONS OF FEMALES

   The data in Figure 5 were obtained from constant
observation  of  individually tagged beasts  kept  in
open-air cages.  As may be seen, the mortality rate
among the population of field voles on the territory
polluted by  strontium 90 was caused primarily by
ionizing radiation during all seasons of the year, the
effect of which is intensified by climatic factors. The
autumn and  spring mortality rates among the popu-
lation of northern  redbacked  voles, a  more radio-
resistant species already  mentioned above that re-
ceived smaller  doses of ionizing irradiation, were
determined by the effects of weather conditions un-
favorable to  the animals. Only in the wintertime was
the more severe destructive effect of ionizing irradia-
tion clear cut.
  Thus, the effect of unfavorable habitat climatic
factors on a  population is intensified against  a back-
ground of ionizing irradiation of the animals' bodies.

The Effect  of  Biotic Factors
  The effect of the usual habitat ecological factors
is intensified  considerably when the population con-
                                                     3  40 .
                                                     £ 40
                                                              REDBACKED VOLES
                                                          Autumn   Winter   Spring
                                                      •i POLLUTED CAGES
                                                      CD CLEAN OPEN-AIR CAGES
                                                      Total for
                                                  FIGURE 5. MORTALITY IN POPULATIONS
                                                              OF VOLES IN A SECTION POL-
                                                              LUTED WITH STRONTIUM 90
                                                              IN WINTER.

                                                 sists of herbivores, weakened by  irradiation by ioniz-
                                                 ing radiation.
                                                   Study of the patterns of the use of a territory by a
                                                 rodent  population,  using individual tagging of the
                                                 animals and conducted by  many  researchers,  has
                                                 shown  that  the  sections  over which these animals
                                                 forage  will change in size,  depending on the effect
                                                 on the  population  of many of the usual  habitat
                                                 factors. Table 1  lists our data on the dimensions of
                                                 the individual sections for  adult male  and female
                                                 field voles during  the  most intensive  reproduction
                                                 period,  midsummer. The population density was the
                                                 same in the polluted and clean open-air cages.
                                                   The  combined action on the  females of ionizing
                                                 radiation and the physiological load caused by preg-
                                                 nancy  and feeding  the young was  expressed by  a
                                                 reduction in the  area of the territory they used to a
                                                 much greater extent than was the case for males af-
                                                 fected just by ionizing radiation.

                     Table 1
Change in the Area of Individual Sections in Popu-
lations of Field Voles Kept in Open-Air Cages in a
Territory  Polluted  by Strontium 90,  M2 (Mature
       Polluted Section
          Clean Area
                                        in area of
                                       sectors from
      Number of Mean Number of  Mean mean dimen-
Sexual individual  area of  individual area of   sions in
groups  sections   section   sections   section control, %
Males     93
Females   134
   Ionizing radiation causes a reduction in the  nat-
ural resistance of the organisms to bacterial exo-
and endotoxins and infections and parasitic diseases.
The increase in the  sensitivity of irradiated animals
probably is caused by a reduction in their  resistance
to infections, and not by an increase in the virulence
of the microorganisms in their bodies. A number of
blood  parasites  were detected in the blood of the
field voles we studied. Most were  leukocytogregarines
(Leucocytogregarinae  microti~).   The   number  of
beasts in  whose blood  endoparasites were detected
was considerably greater in the population subjected
to the constant action of pollution by strontium 90
during all seasons  of  the year  than was  the case
among the control.  Their summertime  number ex-
ceeded the number  of infested voles in the control
cage by a factor of more than 6. None of the control
animals were  found to have  blood parasites  in the
wintertime, generally speaking, whereas  the number
of infested animals was  16.5%  in the experimental
cage. Consequently,  the effect on the rodent popula-
tion of ionizing radiation from the strontium 90 de-
posited in the skeletons was expressed by a substan-
tial increase  in the  number of beasts infested  with
blood  parasites. Moreover, there was an increase  in
the number of blood parasites in the voles thus in-
fected within  the territory polluted by this isotope.
Thus,  1 to 8 leukocytogregarines per 100 leukocytes
were  found  in  the  blood of the control animals,
whereas 40-60 were found in the  blood of voles  in
the polluted area, and in excess of 80-100 speci-
mens in individual cases.
   The beta-radiation effect on the bone marrow from
the radioisotopes deposited in the skeleton caused an
increase in the number of leukocytes in the  peripheral
blood of  the  voles.  The  number of leukocytes was
even  higher  among the beasts  infected with blood
parasites  in the population of field voles living on
the polluted territory. It seems obvious that the effect
of blood  parasites on the bodies of the voles is in-
tensified considerably against  a background of ioniz-
ing irradiation (Figure  6).
   The degree to which the various species of small
mammals can become  infested  with parasitic mites
 found that the number of mites on the infested ani-
 mals,  and the population infestation  rate,  increase
 with increase in the concentration of strontium 90 in
 the boney tissue. These patterns were found to  be
 characteristic for populations of all four species of
   Figure 7 shows the differences in the relative abun-
 dance of gamasid mites on the four species of mature
 rodents, which differences are associated with change
 in the dose-rate of ionizing radiation from the stron-
 tium  90 — yttrium 90 accumulated in the skeleton.
   There is no doubt that irradiation of the bodies of
 small mammals by beta-radiation from the radioiso-
 topes deposited in the skeleton weakens the  animals,
 leads to inhibition of defense  reflexes in protecting
 against ectoparasites, and causes an additional, great-
 er effect by the latter on animals in the population.
                     Changeability in Criteria in Animal

                       As a rule, the effect of pollution of a locality by
                     radioactive fission products on certain parameters of
                     an animal population is studied by comparing the
                     mean values of  the criteria, or properties, of the
                     populations being compared. At  the same time, a
                     number of researchers have shown that an equally
                     important example of the biological effect of en-
                     vironmental factors on an  animal population  is the
                     changeability, or the differing qualitative condition,
                     of the population composition,  reflecting the adapt-
                     ability interrelationship  between the organisms and
                     living conditions and changes  in  these conditions.
                     An  evaluation  of the extent  of the effect  of  pollu-
                     tion  on the population, expressed as the coefficient


                            Long-tailed Mouse
                                           i—i       2
0.12        control
n i
3 V
                           1.4  „„„ 0.003
                               0.12       control

Field Mouse


012       control

a Vole
                             21      0.034
                                 0.36        control
                                          DOSE RATE, rads/day

                         OF BETA-RADIATION IN THE SKELTON

of variation, was found to be a more discriminating
and reliable index than the  mean  value of the cri-
terion (Il'yenko, 1968).
   We studied the changeability in a number of pop-
ulation and morphological criteria in the populations
of certain soil invertebrates and small mammals over
an experimental territory polluted  by strontium 90.
An increase in the degree of changeability in cri-
teria in  the populations in the polluted locality was
a general pattern for all the species studied.
   Organisms incapable of active migrations for long
distances were  selected as the object  for studying
changeability in soil animals. It can be assumed that
the populations in the polluted section consisted only
of animals  that had experienced the effect of ioniz-
ing radiation over the course of  several  generations,
and  which,  moreover, had  not been increased by
immigrants from the surrounding territory. The ob-
servations were of two  species of soil myriapods
among the geophilids. A reliable increase in change-
ability in the number of pairs of legs was noted only
for Pahymerium ferrugineum  males.  A tendency
toward  an  increase in changeability was  noted  for
the remaining  groups,  which  makes  it  important
to take  into consideration  the very rigid control
conditions  (Krivolutskiy,  Smurov, Snetkov, 1972).
All cases of deviation from the norm in the number
of segments in the  antennae (14 in this case)  also
were  taken into consideration  for  all  myriapods.
The  reliability of the  difference in the sampled per-
centages of myriapods with these deviations was eval-
uated by the 0-Fisher method, and leaves no doubt
as to the  statistically reliable increase in. the fre-
quency  with which deformities are found in the ex-
perimental population.
   Figure 8 shows our data (Il'yenko, 1968; Sokolov,
Il'yenko, 1969) on changeability in certain  of the
morphological  criteria in populations  of northern
redbacked  voles  on an  experimental territory pol-
luted by strontium 90 at levels of from 0.6 to 3.4
millicuries/m2.  The coefficient of variation increases
in the majority of the morphological criteria under
these conditions of existence. This points to an in-
crease in the degree of changeability in  animals in a
population inhabiting a  biogeocoenosis polluted  by
strontium  90.   Statistical  processing  of the  data
showed the high degree  of  reliability of their  dif-
ferences. A graphic representation of the distribu-
tion of criteria in the population on  the polluted
territory, and in the control, showed that the excess
in the criteria  distribution curve changes under the
effect of  ionizing radiation, and  the  amplitude of
their changeability in the  population  subjected to
chronic irradiation  increases because of the appear-
 ance of a known number of  animals with the criteria,
the  value  of  which  exceeds  the  limits of change-
ability in the same indices for animals in the control
population. Asymmetry  of  the criteria  distribution
curves will be  seen  in some cases, and  this can be
  Changeability of
  control  population
    rr/7/r i
    ' r/ // '  '
     n/ / / n
     ll/// Al

   I  I// //I  I
    i i// //i  1
  1    K///I
v r r n
Body weight
Body length
Ear length
Tail length
Rel. weight of spleen
Rel. weight of liver
No. leukocytes
No. agranulocytes
Length of cranium
Height of cranium
Width of cranium
No. embryos in females
Life span
    I  I // /\  I
     ' r/ //I I
 Changeability in
 population in
 polluted section
             STRONTIUM 90.

explained by the different effect of ionizing radiation
on different animals in the population. The reliability
of the differences  in the distribution  curves of  the
indices for the populations being compared was con-
firmed by checking in terms of the  chi-square dif-
ference  criterion. The  numerical values  of  the  co-
efficients of variation for different criteria  in the pop-
ulation  increase with increase in the concentration
of strontium 90 in the  skeleton of the northern red-
backed  voles.  Consequently,  the coefficient  of vari-
ation can be  a reliable index of the relationships
between a radioactive environment and animal pop-
ulations when studying the effect of radioactive pol-
lution  of a  territory  considered  a  factor  in  the
organisms' habitat.
   The  increase in the degree  of changeability in
interior (the relative weight of the spleen and liver,
formed  elements)  and  population indices  (fertility
indices, life span, and the like) serves as criteria for
the degree to  which pollution affects animals' bod-
ies, and the population. An increase in the degree of
changeability  in exterior  and craniological criteria,

 which are systematic criteria, may be indices of evo-
 lutionary transformations taking place in the poplua-
   An increase in the changeability of morphological
 criteria in an animal population on a polluted terri-
 tory shows that a change in the direction of natural
 selection can take place, because certain genotypes
 resistant to ionizing radiation  will begin to  predom-
 inate numerically in the population. Natural  selec-
 tion under these conditions inevitably leads, in time,
 to  the  occurrence of  morphophysiological  changes
 in the population, on the way to adaptation of popu-
 lations  to  radioactive  pollution of a locality.
 Effect on Zoocoenosis
   Soil  animals  are one of  the most  convenient  ob-
 jects to use  to  study  the effect of pollution on the
 animal population in  a locality,  because they  are
 closely linked with the soil and vegetation cover,
 are  relatively immobile, and comprise 70-80%  of
 the  total zoomass of land communities.  Then too,
 study of the effect of pollution on soil animals is of
 definite interest. Soil animals  deposit a goodly part
 of the active salts in their bodies  and participate in
 soil-formation processes. The unfavorable effect of
 pollution on soil animals can be shown to be unfavor-
 able for the entire biogeocoenosis.
   The  numbers of mesofauna  were reduced  by  a
 factor of more than 2 in wooded sectors polluted by
 strontium 90 in a density of 1.8-3.4 millicuries/m2.
 The differences were  not the same throughout  the
 warm season of the  year. They reached a  peak at
 the end of summer, the reproductive period for most
 of the  groups of soil  animals  in  the region under
 study (Gilyarov, Krivolutskiy,  1971). Not all groups
 of  major invertebrates  had their  numbers  reduced
 equally in the polluted section, something  particu-
 larly characteristic  of  diplopods  and  earthworms.
 Saprophages, the consumers of the debris layer,  the
 main component  of  the biogeocoenosis  containing
 strontium 90, sometimes were virtually absent in the
 polluted sections.  The number  of  predators  de-
 creased slightly on the  whole,  but sluggish  groups,
 the centipedes in particular, completely disappeared
 from the population.  The number  of predatory bee-
 tles remained almost unchanged. This probably can
 be  explained by  the  appearance  of an  additional
 source of food for the predatory beetles in the form
 of leaf-eating insects, a part of the life cycle,  mov-
 ing through  the soil or plant litter. This additional
 source of food probably compensates somewhat  for
 the direct  action  of  radiation.  Moreover, constant
 increases in  the beetle  populations, at  the  expense
 of surrounding sections, cannot be precluded. Noted
 in the section polluted  by  strontium 90 is extensive
 damage  to  birch  leaves by leaf-eating  insects,  by
gypsy moth,  caterpillars, sawfly larvae, and  others,
in particular. In June  1969, 93.5% of the leaves
here were damaged, as opposed to  2.5%  in the con-
trol.  Radioactive pollution of the  environment also
 had an unfavorable effect on the development of the
 entire soil profile by  soil animals.  The vertical dis-
 tribution of animals on a mean annual basis showed
 a general reduction in the soil population, particu-
 larly that in the deep levels, which cannot  help  but
 lead to weakening the soil formation rate.
   Only  the shelled mites of the microfauna in these
 same sections  were studied in detail. Their  numbers
 in the soils studied were  15-20 thousand specimens
 per  square meter, and   could not  be differentiated
 reliably  between  the  experimental  and control sec-
 tions.  However, the variety  of species of  mites in
 the  polluted territory  was definitely decreased, par-
 ticularly in the case of the species inhabiting the  soil
 surface and the litter.  Thus,  what had appeared here
 was a tendency toward simplification of the coenosis
 in the polluted territory, even with respect  to those
 animals   whose  overall   abundance  remained   un-
 changed. This was particularly characteristic of  the
 species inhabiting the  litter and the upper soil levels
 (Krivolutskiy,  Turchaninova, 1969).  Observations
 of ants are of  interest in studying the effects of pol-
 lution on complexes of land animals, because a con-
 siderable percentage of  the  biomass is made up of
 these animals, and their activities  to  a considerable
 extent regulate the number  of leaf-eating insects. It
 is well known  that ants react keenly to all forms of
 man's economic  activities in the  forest  (improve-
 ment cutting, pasturage,  burning of the litter, proc-
 essing timber  with agricultural  chemicals). In  the
 case of long-term radioactive pollution, we were  un-
 able to detect  any diminution in the ant population
 in a quite large  section  in   which  the control and
 experimental sections  were,  in all  other characteris-
 tics, practically identical, and which, prior to the in-
 troduction of the  radioisotope, were a  single section
 of the forest. It should be added that changes in  the
 ant  population caused by various  forms of man's
 economic activities in  the forest could be readily re-
 corded in the  research area  by using the same pro-
 cedure  (Krivolutskiy,  Baranov, 1972).
   It is interesting that radioactive  pollution  of  the
 environment has a strong, well-recorded effect, even
 on  soil  protozoa  (Korganova, 1973), one of  the
 most radioresistant organisms in nature. This effect
 can  be explained only by the high  level of  radiation
 in the water films surrounding the  soil particles  at-
 tributable to the strontium 90 adsorbed by  the soil.


 Gilyarov,  M. S.; Krivolutskiy, D. A., 1971, "Radioecologi-
  cal  Research  in  Soil  Zoology," Zool. zh. [Zoolosical
  Journal], 50, 3, 329-342.                        *
 ll'yenko, A. I.,  1967, "The  Biological Effect on  a Popula-
  tion of  Voles of Pollution of  the Soil Surface  By Stron-
  tium  90," In collection: Ekologiya mlekopitayushchikh i
  ptits  [The Ecology of Mammals and Birds],  "Nauka"
  Press, Moscow, 122-126.
Il'yenko, A. I., 1968, "The Effect of Pollution of a Section
  of  a  Locality  by  Strontium 90 on Changeability in a
  Population  of  Small Mammals," Zool.  zh. [Zooloaical
  Journal], 47, 9, 90-97.                          * al

Il'yenko, A. I., 1971, "The Degree of Infestation of Popula-
  tions  of  Small  Mammals  By Gamasid Mites in Sections
  Polluted  by Strontium 90," Zool. zh.  [Zoological Jour-
  nal], 50,  2, 243-246.

Korganova, G.  A.,  1973, "The Effect of  Experimental Pol-
  lution of the Soil on Soil Protozoa," Zool. zh. [Zoological
  Journal], 52, 6, 939-941.

Krivolutskiy, D. A.; Baranov, A. F., 1972, 'The Effect of
  Radioactive Pollution of the Soil  on an Ant Population,"
  Zool. zh. [Zoological Journal], 51, 8,  1248-1251.
Krivolutskiy,  D.  A.;  Turchaninova, A.  A.,  1969, "Some
  Changes in  the Structure of the Animal Population of
  Forest Soils Under  the  Effect of Pollution by Strontium
  90," In book: Problemy pochvennoy  toologii [Problems
  of Soil Zoology], "Nauka" Press,  Moscow,  207-209.
Krivolutskiy, D. A.; Smurov, A. V.; Snetkov, M. A.,  1972,
  "The  Effect  of  Radioactive Pollution of the  Soil  by
  Strontium 90 on Changeability of Certain Organisms,"
  Zhurn. obshchey  biol.  [Journal of General Biology],  33,
  5,587-591   .
Sokolov, V. Ye.; Il'yenko, A.  I., 1969, "Radioecology of
  Land Vertebrates,"  Uspekhi sovrem.  biol.  [Successes of
  Modern Biology], 67, 2, 235-255.

       Effects  of Pollution on Species  and  Populations of  Fish
                                           and Birds
                                      Howard E. Johnson *
  In very recent time man  has  attained the ability
to cause major changes in his environment and that
of other  living organisms. As our technology and
populations  continue to grow  human  society has
become increasingly  aware of environmental limita-
tions and  our dependence on stable ecological sys-
  The biota  of  an ecological system are  the result
of long  evolutionary  development  where  balance
and  equilibrium has  been established between or-
ganisms  and  between  these organisms  and  their
environment. The different species within  these bio-
logical communities have  evolved together but each
has developed rather  specific physiological  prefer-
ences and tolerances and they differ in many aspects
of their life  cycles from  the reproductive stage  to
death.  Frequently the species of  greatest value  to
man are those least  tolerant to  environmental fluc-
tuations or those highly restricted in their distribu-
tion  in the environment. Even minor environmental
change may  be  detrimental to their productivity  or
their very existence.
  The strategy  of pollution control to  protect eco-
logical systems differs from that where human health
is a  prime consideration. Rather than effects on the
individual organism our primary concern is for pro-
tection of natural populations,  functional biological
communities or  whole ecosystems. Relative to man,
most animal populations have high reproductive rates
and  short life  spans which produce  a  biological
excess. Therefore, losses of individuals are not sig-
nificant unless the fractional loss reduces potential
harvest by man or is selective  for a particular seg-
ment of the population. This generalization  does not
apply to species of birds or fish that have  long life
spans and low rates  of population turnover.
   Although the goal of pollution control  is directed
toward  maintaining  viable populations  and the  in-
tegrity of biological  communities, our knowledge of
factors regulating such complex systems is deficient.
We  can define the lethal threshold concentration of
a pollutant for an  individual  species,  but the pol-
lutant concentration which will cause a major detri-
mental effect on a community or ecosystem is diffi-
cult to predict.  Thus our immediate  and  most prac-
tical goal is to understand the effects  of pollutants
on individual species that are  known to have major
ecological significance  or are  of greatest economic
benefit to man. If  environmental requirements for
these selected species are determined  and appropriate
controls  implemented, we will have  made  a first
major step in protection of the environment. Protec-
tion of these key species will also protect many other
species that have similar or  greater environmental
  Nevertheless the  selection of beneficial  or key spe-
cies according  to their economic or social value is
disturbing  to many  ecologists.  Some species  not
protected by the  standards may be  eventually elim-
inated from some environments with  a resultant
change in the biological community  structure that is
detrimental to even desirable  species. As we reduce
the diversity of an ecological system  we often de-
crease its stability  and internal  regulation  and re-
quire increased costs  and  energy  in  management.
While this may be appropriate for some forms of
agriculture or highly developed areas it  is not feas-
ible for  all regions.
  Thus  our approach  to ecological problems should
necessarily be conservative. We should identify some
major regions  where  human  activity  is  highly re-
stricted and retain these areas for the continued study
of  natural communities  and to develop  a reservoir
of  species that may be of major benefit to man in
the future.
   But social  and  economic  demands for develop-
ment of new regions  require  that pollution  control
standards are developed now  according  to our best
scientific knowledge.   Within  any major region we
can identify biological communities  and  species that
are of major ecological or economic  importance. Our
research and control  efforts should  be developed to
identify  and protect these species. This includes de-
termination  of critical  pollution concentrations as
  •Associate Professor, Department of Fisheries and Wildlife, Michigan State University

 well as the  unique features of the environment that
 are  required for  their survival; for example, fish
 must have suitable conditions for spawning, migra-
 tion, and food organisms.


    The effects of most  pollutants on an organism or
 a population can be described as a continuum ex-
 tending from concentrations  that  are lethal  after
 short term exposure to a level that has no adverse
 effects even  after  continuous  exposure through  an
 entire life cycle. Intermediate to these extremes, ef-
 fects occur at different levels of  biological organiza-
 tion that may or may not have ecological significance.
 Some changes merely reflect temporary or adaptive
 responses  of individuals within their normal physi-
 ological range.  Ideally, however, knowledge of the
 full range  of dose-effect is important for decisions of
 cost-benefit analysis and to determine maximum per-
 missible concentrations in the environment.

 Lethal Concentration of Pollutants

   Because of their simplicity  short term  toxicity
 tests have  been the method used most frequently to
 measure pollutant effects on fish and birds. In aquatic
 studies,  fish  are generally  exposed to different  con-
 centrations of a toxicant for 4 days and the results
 expressed as the concentration that is lethal to 50%
 of  the fish (96 hr  LC-50). These data indicate the
 relative  toxicity of compounds or  the  sensitivity  of
 various species to a single compound, but the LC-50
 data do not represent  acceptable pollutant concen-
 trations. It has been common practice to estimate
 maximum permissible levels of a particular pollutant
 by  multiplying the LC-50 value by an application
 factor such as 0.1 or 0.05. The value of the applica-
 tion factor is arbitrary  but it is usually  based upon
 scientific  judgment and field evidence  (Sprague,
  In  the  United   Kingdom,  investigations  have
 shown an  empirical relationship between the  esti-
 mated short  term  toxicity  (48 hr LC-50) of mix-
 tures of common  pollutants  and  the  presence or
 absence  of fish  in  certain rivers  (Alabaster  et al.,
 1972). In separate  investigations  with rainbow trout
 (Salmo gairdneri),  Lloyd (1961), Herbert  (1962),
 Herbert and Shurben (1964) and others have found
 the  toxicity of some common pollutants is approx-
 imately additive. The proportional toxicity of each
 toxicant  in the mixture  is obtained by  dividing its
 concentration in the water by the  estimated  48 hr
¥ _  _-     Concentration of Toxicant A in Solution
LC-50, e.g.	
                 48 hr LC-50 of Toxicant A
 = the proportion of the lethal concentration of toxi-
 cant A and similarly for toxicants B, C and D in the
 mixture.  The fractions for all toxicants in the mix-
 ture are summed to give the proportion of the 48 hr
 LC-50 for the  mixture.
    Using  this technique in field studies,  Herbert et
 al.  (1965) found generally good agreement between
 predicted  and observed toxicity in a number of fish-
 less rivers in Great Britain. Alabaster et al. (1972)
 reported  good  fisheries generally existed in  waters
 where  the proportion of the  48 hr LC-50 was ap-
 proximately 0.28 and marginal or no fisheries  existed
 where  the proportion was higher than 0.28.  Brown
 (1968) reviewed the application of this method ac-
 knowledging the lack of scientific basis for additive
 toxicity of toxicants with different lexicological prop-
 erties but  suggested the  various pollutants may each
 produce a non-specific  but additive  overall  stress.

 Sub-lethal and Chronic Toxicity of Pollutants

   There is general agreement among biologists for
 the need  to consider the effects of  pollutants at all
 life stages  of an organism, particularly the effects on
 growth and reproduction. Mount and Stephan (1967)
 described  a chronic toxicity test specifically designed
 to  estimate  acceptable toxicant concentrations for
 fish. The test provides for exposing groups of a single
 fish species to different concentrations of a toxicant
 through an entire life cycle in order  to find the high-
 est toxicant concentration that has no adverse  effects
 on survival, growth and reproduction of the species.
 They suggest an application factor  for the toxicant
 can be  calculated by dividing the "no effect" concen-
 tration  by  the 96 hr LC-50.  The application  factor
 could then be multiplied times the 96  hr LC-50 for
 other species of  fish in another water body to estimate
 acceptable concentrations.
   The  hypothesis for this approach  is that the ratio
 of the "no  effect" concentration and the 96 hr LC-50
 of  a particular  compound does  not vary greatly
 among  different species even though each species
 may vary greatly in their sensitivity to the compound.
 Examples  of acute toxicity values for  several pesti-
 cides and heavy  metals and the calculated application
 factors  are presented in Table  1. In particular the
 data for malathion illustrate the close  agreement of
 calculated  application factors  for different species
 that vary widely in their sensitivity to the insecticide.
 This tends to support the hypothesis that chronic
 toxicity data may have broad application to other
  The  validity  of  predicted  toxicity  from chronic
 toxicity tests in  the laboratory requires  verification
 in field  studies. Eaton (1973) reported that prelim-
inary results  from studies of a natural  stream  inten-
tionally  polluted with copper  seem  to demonstrate
the validity of predictions made from chronic toxicity
tests with copper in the laboratory.

                     Table 1.
Acute and Chronic Toxicity Values and Calculated
Applications Factors for Some Heavy Metals and
Fish Species
  LC«o   Application
 (mg/U   Factor*
2, 4-D


Heavy Metals
Chromium +"




Fathead Minnow
Fathead Minnow
Fathead Minnow

Fathead Minnow
Fathead Minnow

Fathead Minnow
Brook Trout
Fathead Minnow
Brook Trout

Fathead Minnow
Brook Trout
Rainbow Trout
Fathead Minnow
Brook Trout
Fathead Minnow
Green Sunfish
Fathead Minnow
Brook Trout








  • The "application factor" is the ratio obtained by dividing experi-
 mentally determined maximum concentrations of a pesticide that nave
 no detectable effect during chronic exposures by the 96-hour LCm for
 that species.

 Short Term Indicators of Chronic Toxicity

   A major criticism of long term  tests to define
 chronic  toxicity or no effect levels is the long time
 and expense required for the test. It is obvious  that
 such tests can be conducted with only a few of the
 major  pollutants and species  that  are  important.
 Although  additional testing may show  some   data
 have broad application, other tests of shorter dura-
 tion  are  necessary  to  predict  long  term  effects.
 McKim et al. (1970)  have recorded  changes  in
 several  characteristics of brook trout blood  after
 only six days exposure to  copper concentrations that
 eventually  affected  reproduction,  growth, and  sur-
 vival of fish after 8 months  exposure (Figure 1).  In
 subsequent tests, Drummond et al. (1973) recorded
 changes in behavioral activity of brook trout (cough-
 ing response, locomotor activity and feeding activity)
 that appear to be useful as short term indicators of
 copper concentrations that have no long  term effects
 on the species. Cairns et  al. (1973) have similarly
 reported  that  changes  in  locomotor activity  and
 breathing movements of  fish can be monitored  as
 indicators  of  both  lethal and sublethal  concentra-
 tions of zinc in water.
   Although chronic  toxicity tests  may  reveal  pol-
 lutant concentrations that affect reproduction, growth
and survival of fish the practical significance of dif-
ferent degrees of effect must be determined; i.e., how
important is 20% decrease in egg production or fry
survival. Jensen (1971)  used a mathematical model
for yield of a brook trout population to examine the
predicted effect of decreased egg production or in-
creased mortality in "0" age groups, that occur due
to a toxic pollutant.  His results indicate  that even
a  5% increase in mortality of  the  "0" age group
results in a substantial decrease in yield (Figure 2).
More importantly his data indicate that an increased
mortality in the "0" age group would not be detected
as a significant change in the population for at least
two or three years. Thus in natural fish populations,
serious damage could occur  due to  effects on repro-
duction or survival in the early life stages long before
field  monitoring could identify  the change as  dif-
ferent from natural fluctuation in population density.
These results emphasize  again the  importance of a
conservative approach  to setting standards for pro-
tection of fish and  wildlife  populations. Although
threshold  levels of  effect  can  be  identified,  their
values are usually related to only a  few species  and
some allowance is probably  necessary for protection
of other more sensitive  species including food or-


   Bird populations can be affected by the introduc-
tion of biocides and  other toxic materials to the na-
tural environment. The species of birds and number
 of individuals in a particular  region usually  remain
relatively  steady year after year. A major objective
 of wildlife biology is to predict changes in the popu-
 lation  as  a  result of  observing changes in  demo-
 graphic parameters—fecundity  and mortality—and
 to determine the cause of these changes. These para-
 meters are usually measured by the number of eggs
 laid per clutch, frequency at which clutches are laid,
 survivorship of  eggs and young to the  age  of first
 reproduction, and survival of adults throughout their
 lifetime  (Ricklefs,  1973). These  statistics of birth
 and death have been characterized for a hypothetical
 population by  Ricklefs  (1973) to  demonstrate the
 relationship between recruitment, and adult mortality
 as a function of population density (Figure  3).  In
 this example an annual mortality rate of 40 percent
 suggests that the population  density  will increase
 to a density of 125  individuals. As the annual mor-
 tality rate increases the density will decrease and the
 population will  eventually become extinct if the an-
 nual  adult mortality is  over 80  percent. Although
 each  bird species will  have  its  own  hypothetical
 model, these types of data are necessary in order to
 evaluate the effects of a toxic material that is released
 into the natural  environment.

 4 DAY
                                     DECREASE SURVIVAL-ADULTS
                                     DECREASE VIABILITY AND
                                     HATCHABILITY OF EGGS
                                     100% MORTALITY FRY-OUVENILES
                                     24% MORTALITY FRY^JUVENILES
                 GROWTH OF FRY RETARDED^
                                         REVERSIBLE CHANGES
                                         IN BLOOD FACTORS
                                         REVERSIBLE CHANGES
                                         IN BLOOD FACTORS
                                                             |96 HOURS. LC-60UUVENILES)|
                  J'.                       ^
                   I REDUCED FEEDING ACTIVITY]
             "  ^X*
             _ ^^^^^^^^^^^^^•^^•W"<^"*a*«^^^W^HVBBMIIMIWI^^^v^>^^M^^Hpv|
                                        COPPER CONCENTRATION
                                          (jig/ liter)
        SOURCE: (DATA FROM McKIM et. al., 1970: McKIM AND BENOIT 1971,
                AND DRUMMOND et. al., 1973).


                                                   0% INCREASE IN MORTALITY
SOURCE: A.L. JENSEN, TRANS. AMER. FISH SOC. 100 (3): 466-469; 1971.
                                       ADULT MORTALITY RATE
                                 60         80
                           ADULT POPULATION SIZE


   Most  biological  factors  influencing recruitment
 and mortality in bird populations are related to the
 density of individuals. As density increases, mortal-
 ity rates tend to increase and the rate of recruitment
 decreases. The  reverse is true as density  decreases.
 However, the effect of pollutants on bird populations
 is usually independent of density  and mortality  will
 continue  despite a decrease in numbers.  Survival is
 possible only if the population develops  genetic re-
 sistance to  the pollutant. Although there are no
 definite examples of  genetic resistance to  pollutants
 in  birds, Ford and  Prince  (1973)  have  demon-
 strated a wide  range of  genetic  variability  among
 individual mallards  (Anas platyrhynchos)  to  the
 effects of methylmercury chloride  on the production
 of ducklings. Analysis for genetic  variability has not
 been included in most evaluations of toxic materials,
 but  should  probably be included  in future tests to
 improve predictions on  the potential effects of pol-
 lutants on birds.
   Different bird species vary widely  in their response
 to specific pollutants, but  usually species  within a
 taxonomic order show a  more uniform response than
 those  between  orders. Standard test species  in  the
 United States are mallards and ring-necked phesants
 (Phasianus colchicus) (Tucker and Crabtree, 1970).
 These species  are common,  widespread   and  im-
 portant economically in  this country.
   Most pollutants are present in combination in the
 natural environment and present a potential for syn-
 ergistic effects.  Many of these effects will  alter  re-
 cruitment rates  at  lower concentrations than adult
 mortality  rates,  Thus data on reproduction  is neces-
 sary to evaluate the  environmental  impact of most
 pollutants. A discussion  of a  specific pollutant, me-
 thylmercury, can best illustrate these considerations.
   The wide use of mercury and mercury compounds
 in agriculture and industry has  increased  natural
 levels of mercury in certain regions. In Sweden start-
 ing about  1955, a decrease in the popoulation of
 seed-eating birds was  attributed to the use of methyl-
 mercury  compounds  as  seed-dressing  agents.  A
 similar instance  of widespread mercury contamina-
 tion  in the  Canadian prairie and depletion in  the
 abundance of seed-eating birds, including pheasants,
 and  their avian predators has been  reported  by
 Fimreite  et  al.  (1970).  A number  of investigators
 have pointed out that  a reduction in the reproductive
 potential could theoretically occur if pheasants con-
 sumed seed  grain treated with alkylmercury  com-
 pounds (Borg et al.,  1969; Fimreite et al.,  1970;
 Fimreite,  1971;  Adams and Prince,  1972;  Spann et
 al., 1972). Although  only indirect evidence is avail-
 able, this  predicted decline occurred in Sweden, the
 Canadian  prairies, and it may have been responsible
 for declines in pheasant populations in other parts of
 the range  in  North  America. Removal of  the alkyl-
mercurials as seed dressing has apparently corrected
 these problems. A 1966 ban in Sweden resulted in
 an immediate drop  in  the  merucury  levels  in  the
 tissues  of seed-eating birds and a corresponding in-
 crease  in the number of birds (Borg  et al.,  1969;
 Johnels and Westermark,  1969; Jernelov, 1972).
   When other  seed-dressing  agents  such as sub-
 lethal daily doses of  captan, dieldrin, diazinon, cap-
 tan plus dieldrin, and captan plus diazinon are fed to
 laying pheasants reproductive  declines are also  ob-
 served  (Stromborg and  Prince, 1974). They found
 that decreased egg production was the most signifi-
 cant  effect  with  dieldrin  and  captan  acting  ad-
 ditively, while captain and diazison showed signifi-
 cant synergism.

   Some pollutants are of particular concern because
 of their wide dispersal in the environment and their
 tendency to  accumulate  in the food  chain with po-
 tential adverse effects at high tropic levels including
 man. Most chemicals of this nature are synthetic
 organic  compounds  developed  in  the past  few
 decades.  The  chlorinated hydrocarbon insecticides
 such as DDT, dieldrin, and heptachlor are examples
 but  a  number of other  compounds widely used  in
 industry also have properties of persistence, mobility
 and  bioaccumulation.  The polyclorinated biphenyls
 (PCB's) have been used in industry since about 1930
 but their wide distribution and ecological hazard was
 not  recognized until  the late  1960's (Peakall  and
 Lincer, 1970).
   PCB's are used in a variety of products and manu-
 facturing  processes including  synthetic resins,  hy-
 draulic fluids, lubricants and transformer fluids. Their
 loss  to  the  environment has probably  occurred
 through  direct discharge of some fluids  and  oils
 directly to water, loss from  dumps and incomplete
 burning in incinerators, and  vaporization to the  at-
 mosphere. Through transport in the atmosphere and
 in rivers,  PCB's have  become distributed throughout
 the biosphere, and accumulated in various concen-
 trations in invertebrates, fish and birds (Nisbet and
 Sarofim, 1972).
   PCB's  like other chlorinated hydrocarbons  have
 a  very low water solubility   (less than  1 mg/liter).
 In surface waters PCB's  have been reported at con-
 centrations of parts per  billion in  a  few highly  in-
 dustrialized rivers but most  measurements  indicate
 ambient  levels  of 10  to  120 parts  per trillion.
 Acquatic invertebrates and fish can accumulate PCB
 to levels of 103 to 105 times those in the  ambient
 water and sediments.  Because these compounds are
 resistant to degradation they can be passed through
 the food chain to higher trophic  levels. Additional
 accumulation  occurs in birds and mammals associ-
ated  with the aquatic  environment to concentrations

that are 107 to  10s times higher than ambient water
concentrations  (Nisbet and  Sarofim, 1972;  Stalling
and Mayer,  1972).
  The concentrations of PCB in fish and birds indi-
cate   high   levels  of  contamination  in  industrial
regions but low levels are widespread in other areas.
Fish in some highly contaminated waters of the U.S.
have  concentrations  ranging from 10-800 ppm but
average concentrations in fish from various bays and
estuaries or unpolluted rivers  are 1  ppm  or less
(Panel on Hazardous Trace Substances, 1972).
  The PCB's are generally considered to be only
moderately  toxic to  animals  with short term ex-
posure. However, fish appear to obtain their greatest
uptake directly from water and this appears to pre-
sent a greater  hazard than dietary sources. Due  to
their  low solubility in water short-term tests of 96
hours or less do not adequately reflect their toxicity
to fish or other aquatic organisms. The toxicity  of
the various  PCB's varies between species but for  15
day exposure ranges between 50—30 /ug/1  PCB  in
water. With longer exposure the LC-50 values  are
decreased significantly (Stallings and Mayer,  1972).
A pollutant which can be concentrated in organisms
and  is more toxic at longer exposure  concentration
presents an increased hazard to reproduction and
growth.  Some  tests with fathead minnows  (Pime-
phales promelas)  indicate mortality  of adults and
reproductive failure  after continuous  exposure  to
concentrations  of approximately 2 to 8 ppb PCB in
   In the Great Lakes, the eggs of salmon and trout
were reported  to have concentrations as high as  12
to 17 ppm PCB (fresh weight) and may be partially
responsible  for the poor reproductive success of these
species in Lake Michigan (Veith, 1969; Johnson and
Ball, 1972). Johannson et al. (1970)  reported high
losses in prehatching salmon eggs that contain PCB
residue of 14 to 34 ppm  (lipid weight).
   Other indirect effects of PCB on  fish  and bird
populations  have  been  reported.  Hansen et  al.
 (1971)  found a high incidence  of fungus infection
in fish exposed to  PCB in laboratory and Duke et
al. (1970)  found similar lesions in wild fish from an
estuary grossly polluted with PCB. Ducks exposed
to  sublethal concentrations  of  PCB  exhibited  in-
creased susceptibility to viral hepatitis (Friend  and
Trainer, 1970).
   The difficulty of assessing the effect of a chemical
pollutant on wild populations is compounded by the
 simultaneous occurrence  of other pollutants or a
 change in  some other environmental  factor. High
 concentrations of PCB have been found in some wild
 bird  populations that are predators on  fish. Although
 these populations  have   experienced  reproductive
 failure and population declines,  the effect of PCB's
 is not clear because of the presence of DDT, mercury
 and other toxins. Where compounds affect reproduc-
tion, growth and behavior  of organisms at concen-
trations below the acute lethal level, the effect may
be expressed as a slow change in the size or relative
abundance of a population.  At present, levels of PCB
in many parts of the environment occur at concen-
trations that  exceed levels known to have  adverse
effects on organisms in  the laboratory. Therefore,
it is likely that adverse effects are occurring in popu-
lations or communities but  it is very difficult to show
this conclusively.
   Many new chemicals which are potentially hazard-
ous substances  are  introduced  into commerce an-
nually. Strategy  for control of these  pollutants must
be  directed at identification and testing for harmful
environmental effects before they  are used in large
quantities or widely distributed  in the environment.
Many of our present techniques for testing the toxic-
ity of new compounds are  inadequate for evaluation
of  their environmental impact.  Consideration must
be given to testing in more sophisticated model eco-
systems  and  biological communities where  rates of
transport, degradation, bioaccumulation and  trophic
transfer can be evaluated.
   Models to  describe sources, transport  pathways
and effects within global and regional environmental
areas are needed  to define monitoring  schemes. An
example  of such  a descriptive  model  is shown in
Figure  4. Such  models may have broad application
for predicting movements  and effects of many com-
pounds that have  similar properties  and distribution
in  the  environment.  Perhaps more  than any other
form of pollution the problems associated with per-
sistent  synthetic compounds emphasize the  import-
ance of a conservative  approach in pollution con-

   Although we often investigate the individual effects
 of pollutants on an organism, it is evident that effects
 in environmental systems are usually  multiple and
 highly  complex.  Attempts to set maximum  permis-
 sible levels of a pollutant  must consider the full
 range of environmental interactions that may occur.
   Temperature is  an example  of an environmental
 factor  that has multiple  effects on  aquatic systems.
 Heated water discharge for electrical power plants is
 expected to increase in the next 30 years with sub-
 stantial quantities of our surface waters used in the
 cooling systems.  Individual heated discharges may
 have only minor effects on the  environment  but col-
 lectively several discharges  in  close proximity may
 create  major  environmental changes.
    Individual  aquatic species have specific  thermal
 requirements that differ according to their life stages
 and  influence  their  success  in  the  environment.

                            HIGHER CARNIVORES
                             FIRST CARNIVORES
                                   BOTTOM ORGANISMS
                                           EXCRETION AND DECAY
            SOURCE: ENV.RONMENTAL RESEARCH 5:249-362; 1972
                        IN THE FRESHWATER ENVIRONMENT

Heated discharges can be managed to promote cer-
tain  species if  these requirements are known and
protected. The maximum and minimum tolerance of
desirable organisms may dictate the allowable  dif-
ferential between heated discharge and ambient water
temperature. Thermal stress which is not lethal can
have detrimental effects by  increasing an organism's
susceptibility  to predation  (Coutant, 1969). Each
species also has some physiological  optimum tem-
perature  for  growth.  However,  as temperature  in-
creases food requirements also increase  (Brett et  al.,
1969) and eventually a temperature is reached where
growth ceases because of the high metabolic demand.
Species that are forced  to  live near  these marginal
temperature extremes may be competitively excluded
by species of greater thermal tolerance.
  Fish in temperate climate zones require a seasonal
fluctuation in temperature or winter chill period  for
successful development of the gametes and  spawning.
A period of low temperature is  apparently required
to allow storage of yolk material  which cannot be
effected successfully at higher temperatures because
storage of food material is prevented at the  higher
metabolic  rate (Merriman and Schedl,   1941). If
fish  are  attracted to and remain in  elevated water
temperatures  during the winter months  they may
suffer reproductive failure.
  Other effects of  temperature  that may indirectly
affect populations of  aquatic organisms result from
interaction with other pollutants. Macek (1969) re-
ported insecticide toxicity  to  fish  was increased at
higher temperatures and Edsall and Yocum (1972)
reported lake trout  (Salvelinus namaycush) doubled
their rate of methylmercury accumulation from water
when the water temperature was increased from 5 °C
to 10°C. Pretreatment or exposure to a toxicant may
reduce the tolerance to thermal stress in fish (Silber-
geld, 1973).
   An increased incidence of various  fish diseases
has  been  associated  with  elevated  water tempera-
tures in  various locations  (Mihursky, 1969; Brett,
1956). Ordal  and  Pacha  (1967)  found increased
virulence and effect of several diseases  on salmonids
held at increased water temperature.
   There  is also some indication that  heated water
discharges may accelerate the process of eutrophica-
tion  in  lakes  and  create  conditions favorable  for
nuisance algae (Patrick, 1969).
   Temperature of course  is only one of the many
environmental  variables that cause multiple or "syn-
ergistic" effects with other pollutants  and different
organisms. Nearly any  pollutant can have multiple
effects, many of which are  not recognized until after
harmful  effects have occurred. Wood, 1971 (cited by
Bahr, 1972)  reports the  interaction of stream  and
lake enrichment by sewage effluent and the discharge
of  inorganic  mercury  as  an  example.  The large
bacterial populations created by sewage enrichment
 act  as an  "environmental catalyst" in the formation
of the highly toxic  methylmercury. Bacteria were
probably always present in natural waters  and so
were small amounts of the element mercury. But in-
creased discharge  of elemental  mercury  in  the
presence of high bacterial  populations allowed  the
accelerated production of methylmercury. Fish, birds
and human populations  have suffered from this  un-
predicted combination of environmental events.

   The laboratory testing of pollutant effects  with
important species has been recognized  as a practical
and necessary method for development of immediate
pollution control standards. However, the limitations
of the data obtained for a single species under highly
artificial conditions is also recognized.  An  organism
exists in nature as an integral part of  the biological
community, both exerting effects and being affected
by interactions within the system. Improved methods
for evaluating pollutant effects are needed to measure
population or community responses to toxicants or
other environmental perturbations. This  is the next
logical  step  for  understanding  the significance of
effects observed at the species or individual organism
   Warren and Davis (1971)  have described methods
of using  laboratory stream  ecosystems to measure
dynamics of primary and secondary production of
relatively simple communities of organisms. Even in
these  simplified  systems the interactions between
biotic and abiotic variables are  complex, but much
greater control can be exercised than in truly natural
communities. The information obtained  from these
simulated communities  or ecosystems offer a  new
level of sophistication for interpretation  of environ-
mental changes.
   Maki  and Johnson (1974) have used a series of
model streams colonized by natural stream organisms
to assess  the effect of a  toxicant TFM (3-tri-fluoro-
methyl-4-nitrophenol) on community  structure  and
metabolism.  TFM, which is used in streams to con-
trol populations of the parasitic  sea lamprey  (Petro-
myzon marinus), was introduced into  streams under
simulated field conditions. Their data show the toxi-
cant caused  immediate but reversible changes in the
composition and abundance  of sensitive invertebrate
 species and in the productivity of algal communities.
 Using radiolabeled TFM in  separate sections of the
 stream they were able  to measure the translocation
 and accumulation  of residues in various  organisms
 and the sediment.  Although each of their measure-
 ments could have been conducted in isolated systems
 or  with individual species,  only  by using a model
 community were  they  able  to  measure the rate  of
 change and interaction of the different species.

   Model  aquatic ecosystems have also been em-
 ployed to  study  the  uptake and translocation  of
 chemicals between several trophic  levels. Isensee et
 al. (1973)  studied  the distribution of radiolabeled
 alkyl arsenicals in algae, snails, Daphnia, and fish in
 a simulated food chain. Their data provide informa-
 tion  on  the potential  for  bioaccumulation by the
 various species and  transfer to higher trophic levels.
   Each of the above examples is  an attempt to im-
 prove on methods for assessing  the effects of pol-
 lutants in the environment. Undoubtedly new, more
 precise methods  will be  developed. Although these
 methods  will be  more  expensive initially the results
 should greatly improve our  ability to predict and
 control environmental problems.


   Human  society in its present form is highly de-
 pendent  upon stable  biological   communities  that
 form the basic structure of our life support systems.
 Our  failure  to  recognize the  integrated nature  of
 ecological systems and  man's  dependence upon them
 has led to many  of our present environmental prob-
   Natural biological communities in a region consist
 of populations of organisms that have many common
 attributes.  These  similarities  form  a common  de-
 nominator necessary for effective  function and regu-
 lation of  ecological systems. An immediate and prac-
 tical need for pollution control is  to recognize and
 protect the environmental requirements  of individual
 populations of species within these regions. However,
 this must be considered a limited first step and much
 greater effort should be given to understanding the
 interrelationships between populations and communi-
   Regional resource management plans offer an op-
 portunity to view entire  biological  communities  or
 ecosystems  as  functional units. Even  at this level
 of organization we can err in management  practices
 if we  consider such regions  as independent  units.
 Ecological  systems do  not have distinct  boundaries
 and change in one region will often effect changes in
   Fish and wildlife  populations are only one com-
 ponent of  biological communities  that we wish  to
 maintain. However,  in  addition to their  social and
 economic value, species of fish and birds often serve
 as  important  indicators  of   environmental  quality.
 Their  role and general  productivity within  a region
 are indicative of change  that  may  be either to the
 benefit or detriment  of  human society.


   I extend my appreciation to the  following people
for their assistance in preparation of the manuscript:
 Dr. Harold Prince, Dr.  Walter  Conley, Mr. Alan
 Tipton, Ms. Judy Boger and Ms. Jackie Church.


 Alabaster, J. S., J. H. N. Garland, I.  C. Hart and J. F. DC
   L. G.  Solbe. 1972. An approach to the problem of pol-
   lution and fisheries. Symp. Zool. Soc. Lend. No. 29: 87-
 Adams, W. J. and H. H. Prince. 1972. Survival and repro-
   duction of ring-necked pheasants  consuming  two mer-
   curial  fungicides.  P. 306-317 in Environmental Mercury
   Contamination, R. Hartung and B. D. Dinman, Editors.
   Ann Arbor Science Publishers, Inc., Ann Arbor,  Michi-
   gan, U.S.A. 349 pp.
 Bahr, T. G.( R. A. Cole and H. K. Stevens. 1972. Recycling
   and  ecosystem response to water manipulation. Tech.
   Rept. No. 37: 124 pp. Institute  Water Research, Mich.
   State Univ., East Lansing, Mich. 48824.
 Borg,  K., H. Wanntorp,  K.  Erne,  and E. Hanko.  1969.
   Alkyl  mercury poisoning in terrestrial Swedish wildlife
   Viltrevy 6(4): 301-379.
 Brett, J.  R.  1956. Some  principles  in the thermal require-
   ments  of fishes. Quart.  Rev. Biol.  31(2): 75-87.
 Brett, J. R., J. E. Sbelbourn, and C. T. Shoop. 1969. Growth
   rate  and body composition  of  fingerling sockeye salmon,
   Oncorhynchus nerka in relation to temperature and ration
   size. J. Fish. Res. Bd. Canada 26(9): 2363-2394.
 Brown, V. M. 1968. The calculation of the acute toxicity
   of mixtures of poisons to rainbow trout. Water Research
   2: 723-733.
 Cairns, J., Jr., R. E. Sparks, W. T. Waller. 1973. The rela-
   tionship between  continuous  biological monitoring and
   water quality  standards  for chronic exposure P. 383-402
   in Bioassay Techniques  and Environmental  Chemistry,
   G.  E. Glass, Ed. Ann Arbor Science  Publishers, Inc.,
   Ann Arbor, Michigan, U.S.A.
 Coutant, C.  C.  1969. Temperature, reproduction and  be-
   havior. Chesapeake Science 10(3&4): 261-274.
 Drummond,  R A.,  W A. Spoor, and G. F. Olson.  1973.
   Some short term  indicators  of  sublethal effects of copper
   on  brook  trout,  Salvelinus fontinalis. J. Fish. Res. Bd
   Canada 30: 698-701.
 Duke,  T. W., J. I.  Lowe,  and A.  J. Wilson, Jr. (1970).
   A polychlorinated biphenyl  (Aroclor 1254) in the water,
   sediment, and biota of Escambia  Bay, Florida. Bull. En-
   viron. Contam. Toxicol. 5: 171-180.
 Eaton, J. G. 1973.  Recent developments in the use of lab-
   oratory bioassays to determine "safe" levels of  toxicants
   for fish. PP.  107-115, in Bioassay Techniques and En-
   vironmental  Chemistry, G.  E. Glass, Ed.  Ann  Arbor
   Science Publishers, Inc., Ann  Arbor, Michigan, U.S.A
 Edsall, T. A. and  T. G.  Yocum. 1972. Review of recent
   technical information concerning  the adverse  effects of
   once-through cooling on Lake  Michigan. Lake Michigan
   Enforcement  Conference, September  19-21, 1972, Chi-
   cago, Illinois. 86 pp.
 Fimreite, N.  1971.  Effects of  dietary  methylmercury on
   ring-necked pheasants.  Canadian  Wildlife Service Occa-
   sional Paper No. 9. 39 pp.
 Fimreite, N., R. W. Fyfe, and J. A. Keith. 1970.  Mercury
   contamination of Canadian  Prairie  seed eaters and their
   avian predators. Canadian Field Naturalist 84(3): 269-
 Ford, J.  R. and H. H. Prince. 1972. Effects of methylmer-
   cury chloride on mallard reproduction. Presented at 1972
   Annual Wildlife  Disease Conference, June  13-15, Uni-
   versity of Michigan, Ann Arbor, Mich.
 Ford, J. R. and H. H. Prince. 1973. Distribution and excre-
   tion of methylmercury chloride in mallards. Presented at
   35th Midwest Wildlife  Conference, December 2-5, 1973,
   St. Louis, Missouri.
Friend, M. and  D.  O. Trainer.  1970. Polychlorinated bi-
   phenyl: Interaction with duck hepatitis virus. Science
   170:  1314-1316.
Hansen, D. J., P. R. Parrish, J. I. Lowe, and P. D. Wilson.
   1971. Chronic toxicity, uptake, and retention of Aroclor

  1254 in two estuarine fishes.  Bull. Environ. Contain, and
  Toxicol. 6(2): 113-119.
Herbert, D.  W. M. 1962.  The toxicity to rainbow trout of
  spent still liquors  from  the  distillation  of  coal.  Ann.
  Appl. Biol. 50:755-777.
Herbert, D.  W. M. and D.  S. Shurben.  1964. The  toxicity
  to fish of mixtures of poisons. I.  Salts of ammonia and
  zinc. Ann. Appl. Biol. 53:  33-41.
Herbert, D.  W. M.,  D. H. M. Jordan and R. Lloyd.  1965.
  A study of some fishless rivers in the industrial midlands.
  J. Proc. Inst. Sew. Purif., pp. 569-582.
Isensee, A. R., P. C. Kearney, E. A. Woolson, G. E. Jones,
  and V. P. Williams. 1973. Distribution of alkyl arsenicals
  in model  ecosystem. Environ. Sci. and Tech.  7(9): 841-
Jensen, A. L. 1971. The effect of increased mortality on the
  young in  a population of brook trout,  a theoretical anal-
  ysis. Trans. Amer.  Fish. Soc.  100(3):  456-459.
Jemelov, A. 1972. Mercury  and food chains. P.  174-177 in
  Environmental  Mercury Contamination,  R. Hartung and
  B. D.  Dinman, Editors. Ann Arbor Science  Publishers,
  Inc., Ann Arbor, Michigan, U.S.A. 349 pp.
Johnson, H. E. and R. C. Ball. 1972. Organic pesticide pol-
  lution  in  an aquatic environment, pp. 1-10  in  Fate  of
  Organic   Pesticides  in  the Aquatic   Environment, Ad-
  vances in  Chemistry Series, No. 111.
Johnels, A.  G.  and T. Westermark. 1969. Mercury  contam-
  ination  of the  environment  in  Sweden.  P.  221-241  in
  Chemical Fallout, M. W.  Miller and G. G. Berg, Editors.
  Charles C.  Thomas, Springfield, Illinois. 531  pp.
Lloyd, R. 1961. The toxicity of mixtures of copper sulfate
  to rainbow trout  (Salmo gairdneri  Richardson). Ann.
  Appl. Biol. 49: 535-538.
Maki,  A. W. and H. E. Johnson.  1974.  Effects  and fate of
  TFM   (3-trifluoromethyl-4-nitrophenol)  lampricide  in
  model streams.  Presented at  24th Annual Meeting, Mid-
  west Benthological Society, Cincinnati, Ohio,  March 27-
  29, Cincinnati,  Ohio.
McKim, J.  M. and  D. A. Beneir.  1971.  Effects  of long-
  term exposure  to  copper on survival,  growth and  repro-
   duction  of brook  trout  (Satvelinus fontinatis).  J.  Fish.
   Res. Bd. Canada 28(5): 655-662.
McKim, J.  M., G. M.  Christensen,  and  E. P.  Hunt. 1970.
  Changes  in the blood  of brook  trout (Salvelinus fonti-
  nalis)  after short  term and  long term exposure to cop-
  per. J. Fish. Res. Bd. Canada 27:  1883-1889.
Merriman, D. and H. P.  Schedl. 1941. The effects of light
  and temperature  on  gametogenesis  in  the  four-spined
  stickleback, Apeltes quadracus (Mitchell). J. Exp. Zool.
  88(3): 413-449.
Mihursky,  J.  A., A. J.  McErlean, and  V.  S. Kennedy.
   1970. Thermal pollution in aquaculture and pathobiology
  in aquatic systems. J. Wildl. Dis. 6: 347-355.
Mount, D. I. and C. E. Stephan. 1967. A method for estab-
  lishing acceptable  toxicant  limits  for  nsh-mamathion
  and the  butoxyethanol ester of 2. 4-D.  Trans.  Amer
  Fish. Soc. 96:  185-193.
Nisbet, I. C. T.  and A. F. Sarofim. 1972. Rates and routes
  of transport of PCB's in the environment. Environ. Health
  Perspectives 1:21-38.
Ordal, E. J. and R E. Pacha. 1967. The effects of tempera-
  ture on  disease  in fish. In  Water Temperatures:  influ-
  ence,  effects  and control.  Proc.   12th  Pac.  Northwest
  Symp. Water  Pollut.  Res., Portland, Oregon.  Fed. Wat.
  Pollut. Contr.  Admin.
Panel  on   Hazardous  Trace   Substances   Report  1972.
  PCB's—Environmental  Impact.  Environmental  Research
Patrick,  R.  1969.  Some effects of temperature on fresh-
  water  algae, pp. 161-185.  In Biological Aspects of Pol-
  lution, P. A. Krenkel and F. L. Parker, Editors, Vander-
  bilt University Press. 407 pp.
Peakall,  D. B. and J. L. Lincer.  1970 Polychlorinated  bi-
  phenyls:   Another long-life widespread chemical  in  the
  environment. BioScience 20: 958.
Ricklefs, R. E.  1973. Fecundity, mortality and ayian dem-
  ography,  p. 366-435. In Breeding Biology of Birds, D. S.
  Farner, Ed. National Academy of  Sciences, Washington,
  D.C. 515  pp.
Silbergeld,  E. K. 1973. Dieldrin. Effects of chronic sublethal
  exposure  on  adaptation to  thermal stress  in  freshwater
  fish. Environ.  Sci. and Tech. 7(9): 846-849.
Spann, J. W., R. G. Heath, J. F. Kreitzer, and L. N. Locke.
   1972.  Ethylmercury  p-tolune sulfonanilide:   lethal  and
  reproductive  effects on  pheasants.  Science 175  (4019):
Sprague, J. B. 1971. Measurements of pollutant toxicity to
  fish-Ill.  Sublethal effects and safe concentrations. Water
   Research 5: 245-266.
Stalling, D. L.  and F.  L. Mayer, Jr. 1972. Toxicities of
   PCB's to fish  and environmental residues. Environ. Health
   Perspectives 1: 159-164.
 Stromborg, K.  D. and H. H.  Prince. 1974  Pesticide inter-
   actions:  Alteration of reproductive  performance in pheas-
   ants fed combinations of seed treatments. (In press).
 Tucker,  R.  K.  and D. G.  Crabtree.  1970.  Handbook of
   toxicity  of pesticides to wildlife. U.S. Dept. of Interior,
   Bureau of Sport Fisheries  and Wildlife Resource Publica-
   tion No. 84. 131 pp.
 U.S. Environmental Protection  Agency.  1973.  Effects of
   pesticides in water-a report  to  the  States. USEPA, Wash-
   ington, D.C. 20460.145 pp.
 Veith, G.  D. 1972. Recent  fluctuations of chlorobiphenyls
   (PCB's)  in the Green Bay,  Wisconsin, region. Environ-
   mental Health Perspectives 1: 51-54.
 Warren, C.  E.  and G. E. Davis. 1971. Laboratory stream
   research:  objectives,  possibilities  and  constraints. Ann.
   Rev.  Ecol. Syst. 1: 111-144.

                 The Influence of Environmental Factors  on
                Population Dynamics (Mathematical  Model)

                                      M. Ya. Antonovskiy *
  1. We shall, in this  report,  discuss the following
thesis. A population is  a complex system containing
a great  many  different heterogeneities that do, and
do not,  appear directly. At the same time, the ob-
served, relatively stable, regime in which a population
functions  is the resultant of  the  effects  of  many
factors,  a number of which can cause instability.
  The effect of the environment on a population can
remove  it from its  stable regime and can bring into
play internal  mechanisms embedded in the popula-
tion which can lead to the fundamental restructuring
of the population,  even when  the magnitude of the
external effect is small (more  precisely, when  there
is a small change in the level of the effect of the en-
vironment on the population).
  We shall, in this report, consider simple mathe-
matical  models of the different processes that can
take place in  "theoretical" populations that will, in
our opinion, quite  graphically  illustrate the different
aspects  of the thesis we have set forth.
  If we are to apply the results we obtain to real
populations, it goes without saying that we must con-
struct a model that will take into  consideration the
specificity of  the interaction between the  different
factors  in these populations. The appearance of this
specificity can be expressed in the form of the corres-
ponding quantitative  dependencies  constructed  on
the basis of a statistical analysis of the observed data.
However, the  difficulties  that can  arise  when  at-
tempting to determine the precise form of the quan-
titative  dependencies in biological systems are well
known. Consequently,  the approach to their  study,
which A. N. Kolmogorov [1] has defined as "obtain-
ing quality results  from quality prerequisites," is an
extremely valuable one.
   2.  First of  all, let us consider the phenomenon of
the influence of the environment on the nature of the
appearance of the internal mechanisms that depend
on  density, and which regulate the dynamics of popu-
lation number and structure.
   Study of the influence of density on  population
dynamics,  experimentally, as  well  as  using mathe-
matical models, began a very long time ago.

  •Central Institute of Economic Mathematics, Moscow
  The logistic equation

    dN/dt = N(a-bN)
was considered for the first time in connection with
study of population dynamics by Fehrhulst in 1844,
and led to the conclusion that there was a stationary
level for the number to which the number in a pop-
ulation would  tend  monotonically.  This fact is  a
classical example of negative feedback.
  This conclusion retains its force,  even when one
must solve the more general equation
    dN/dt = Nf(N)
       f (N)  is a monotonically decreasing function,
             change in the sign of which  has  no
             effect  on the conclusion reached as to
             the monotonic  tending  to  some  sta-
             tionary level.
In fact, there are four types of number dynamics for
populations functioning in  a  steady-state (in terms
of time) environment that can occur  (and they can
be observed). These are:
   (1) there is  a steady stable  state to  which the
system tends monotonically;
   (2) there is  a steady stable  state to  which the
system tends in  the form of attenuating oscillations;
   (3) there is  a stable,  periodic, regime.  At the
same time, the magnitude of  the period can be dis-
associated from  the values for certain  of the  biologi-
cal characteristics of the population (sexual matura-
tion period, life span, and the  like);
   (4) the number undergoes irregular oscillations.
   A discussion of this subject, as well as a great deal
of experimental  data, is contained in the basic mono-
graph written by Andrewartha and  Birch  [2].  The
book by Makfed'yen [3], while shorter, is full of in-
formation on this subject.
   Population heterogeneity  (and age differentiation
in particular) is the most obvious candidate for the
role of the cause of the effects listed.
   However, at this point let us turn our attention to
other possible causes.  It may well be that the same

 population can experience all the types of dynamics
 listed, depending  on the intensity of the effect of
 some external factor, such as a chemical or a phy-
 sical agent, for  example, that could  have an effect
 on the fertility  of females, or on the survival  rate
 of specimens. Another example of an external factor
 is the degree of  industrial exploitation of the popula-
   This can be demonstrated  on a model  that does
 not  take  population heterogeneities into considera-
   Let us  illustrate  what we have  said by a  well
 known example. Let a population consist of speci-
 mens that have reached sexual maturity at year 1,
 arid let the natural mortality and the fertility  of the
 females be independent of age. Further, let the num-
 ber  of additions to the population per mature speci-
 men be expressed by  the monotonically decreasing
 function v(N,/t). This function depends on the num-
 ber  of mature specimens, N, as  well as on the para-
 meter p., characterizing the influence of the environ-
 mental factor.
   In this case the population  dynamics equation has
 the  form
                                                         A<>— Ae
N(t + 1) = ( 1 - \)N(t) + N(t)
 Here X is the mortality factor.
   We shall not, here,  dwell on  the  formulation of
 the general theorems  that can be  proven naturally
 with models of this type, but instead will consider the
 concrete, often encountered, example where
        c  is some constant characterizing the eco-
          logical capacity of the environment.
   0                                          N

   Eq. (4) makes it clear that the number of addi-
 tions increases with increase in p..
   Investigation of this model permits us to draw the
 following conclusions:
                       Monotonic growth   Case 1
                       to stable steady
                       Tending to steady   Case 2
                       state with attenu-
                       ating oscillations
                       Periodic or non-  Cases 3
                       periodic regime      and 4
     We should point out that when /i>Ae2/x,  the
steady state will become  unstable and the  type of
dynamics will depend on /x, as well as on the original
number in  the  population  (as distinguished from
cases 1  through 3).  The type of dynamics will, for
example, depend on the state in which the population
was  found when the parameter /x took a new value.
There is a stable periodic regime for  certain values
of p in  which the  population will be  found for the
"majority" of original conditions. Although the set of
such original conditions for which the  population
will not be found in this regime is a  small one, it has
a measure of zero, the role of  such conditions does
manifest itself in the fact that  in the case of other
original conditions the reaching of the stable periodic
regime is preceded by a more or less lengthy period
(one that depends on the  original conditions) of ir-
regular  oscillations  "simulating" these unstable re-
gimes. The length of the period  will change in a most
complex fashion with increase in /x. There are certain
11 values at  which a  phenomenon corresponding to
case 4 will occur, and this we can call  the ergodicity.
The  period of the stable cycle will become very large
when the xi  values are close to this, and periodicity
will  in fact disappear.
  Let us consider in detail what happens when the
parameter /*. passes through the critical value Ae2/x.
A trajectory with a period  of 2(N,, N2, Nu N5, . . .),
which has the  following properties, will  appear in
the neighborhood of the steady state  N= 1/c  In LI/A:
  (a)  it is  locally  stable; that is, for any  original
value N(O) sufficiently close  to Na,  N(2t)-»N,,
N(2t+l)->N2, when t-*°o;
  (b)  at the  same  time there are  those  original
values N(O), the numbers for which N(t),  do not
tend to this stable trajectory;  for  example, N(O)
= l/c In /x/A;
  (c)  let us designate by  A the set of those original
values N(O) for which t exists such that
       N(t) = l/cln tiA.
Then A is an infinite denumerable set. The situation
described in (b),  above,  will  occur  for  any value
N(O) of the closure A of set A. The trajectory will
tend to the  original  trajectory  of period  2  for  any
other_ original values. It is curious to note that the
set A is a "perfect Cantor set" of measure zero.
  Similar effects  are retained in more complicated
models, in those closer  to reality, in which  the age

structure of the population, change in fertility with
age, and so on, are taken into consideration.
  These models show that predetermined levels of
effect of a hypothetical external factor  are  critical
so far as the population is concerned; that is, the
population will change its type of behavior when such
value is reached.
  There can be a situation in  which the presence
in the environment of an important ingredient, one
however that is difficult to  measure by using direct
methods,  can be  established  from the behavior of
"indicator" populations that had been well-studied in
laboratories,  definite species of micro-organisms, or
plants, for example.
  We should point out that in recent years many of
the published papers have considered population dy-
namics models based on  type  4  relationships, or
similar models with divisions into  a small number
of age classes. We can, by way of an example, point
out reference [4], which deals with humpback salmon
population, and in which a critical  value was found
at which the "natural" regime loses stability and in
which computer data are cited  for the case  corre-
sponding to the last row in our table.
  3.  Let us now go to the influence of the environ-
ment on a population that  is the result of  the effect
on the genetic mechanism. The first phenomenon we
shall  analyze is the following. A genetically  hetero-
geneous population in a steady  (in some  particular
sense) state can be subjected to the effect of environ-
mental  factors that act  on specimens of different
genotypes in  a  differentiated manner. In this case the
environmental  factors act as a selection mechanism,
and the rate at  which this selection is made  can prove
to be extremely high. However,  if,  at the same time
the influence of density on population dynamics still
is taken into  consideration, it  can be  shown  that
even  the presence  of a small advantage, obtained by
a definite part of  the population as a result of  the
effect of an  environmental  factor,  can,  with  the
passage of time, lead to  a  fundamental rearrange-
ment of the genetic structure of  the population (dis-
appearance of  certain genotypes, and the like).
   Let us  consider the following  simple  model in
order to explain this thesis.
   Let us  assume the population to  be  genetically
heterogeneous  and consisting of  two species (pheno-
types). These  phenotypes can be distinguished by a
character that can be determined by one gene, found
in two variants, a dominant A  and  a  recessive a.
Crossing of them takes place in  accordance with the
Hardy-Weinberg law, and  each of the species  ex-
periences  pressure from the number in  the entire
population, as described  in  paragraph 2,  for  ex-
ample. We can assume, however, that the value of
the parameter  /i characterizing the effect of the  en-
vironment is  different  for  the   two  phenotypes,
although  both values are  in  the zone ensuring  the
existence of a stable steady state. Let us further sup-
pose that A = 1; that is, that each generation produces
offspring once. This  assumption  is not critical for
conclusions  that can be reached using a model, but
simplifies the calculations. If we designate the num-
ber of the  total population at time t by  N(t), and
the share of gene A in the genofund of the offspring
produced by the generation living at time t as  x(t),
         x(t+ 1) =
                 - x
N(t +

= juN(t)e-cN (t) [l - a[ 1 - x(t)]2]
       /*! = fj. is the value of the environmental factor
             for  the  phenotype  corresponding to
             genotypes A A and Aa;
  /x2 = /i(l-a) is the value of this factor for the  0<
             < 1 phenotype corresponding to geno-
             type aa.
  In both  these numbers lie between 1 and  3, the
net populations containing only genotype AA, or
only genotype aa, have stable  steady numbers,  and
the difference between them is small if a is small.
  It may readily be seen that the mixed population
too has a stable steady state:
       x= 1, 1/c In /*,
during which  the recessive species  disappears.  But
it is  more  interesting to estimate the rate at  which
this species is displaced.
  Eq. (5)  will provide this estimate quite readily.
  For example,  if  the  original percentage of the
species with genotype AA is equal to p0, and is equal
to P!  after  time n, we have
-ln[l Xa(l Xp,,)2)]      -In [1-«(1 -Pi)2)]
   The  second example of the influence  of  the en-
vironment on  the  population through  the  genetic
mechanism that we shall  analyze illustrating the
theorem is that the genetic species can prove  to be
necessary in order  to maintain  the number of the
population  under  variable  (periodically  changing,
for example)  environmental conditions.
   It has  long been established (references [6, 7,  8]
for example)  that there are  clearly expressed differ-
ences  between  generations in populations  of  some
small  rodents, and  other animal "ephemerals" that
live for a few months and multiply several times in
the  summertime. The situation  can  be described,
albeit  very roughly, as follows.
   Specimens with relatively low fertility predominate
in a generation that overwinters  and has  offspring at
the beginning of the season. However, a generation,

 for example, that is born in the first half of the sum-
 mer  ("descendants" of  the previous generation)  is
 predominated by specimens with a very short sexual
 maturation period,  is very fertile, and has  a short
 life span.  Since  the population  is substantially re-
 duced during the wintertime,  the  population is re-
 stored to  its  former figure.  It is considered estab-
 lished,  at  least for  some populations, that  the dif-
 ference  between  the species we  have described
 ("living through the winter" and  "summer") is in
 fact genetic in nature.
   We have been considering a very simple  mathe-
 matical  model that suggests one  possible approach
 to an explanation  for the need for periodic rear-
 rangement of the genetic structure of a population
 in order for that population to survive.
   Just  as  was the  case  with  the preceding models,
 we must bear in mind  the fact  that our purpose
 simply is to present a graphic, mathematically cor-
 rect demonstration  of a definite phenomenon by the
 example of a  simple "theoretical  population." We
 should note that a number of the simplified assump-
 tions can be discarded without creating any difficul-
 ties. There are others that are more significant in
 content, however, and which we shall discuss in what
 follows,  that must be taken into consideration, even
 in the more complex models, those in which the
 effect of the influence of polymorphism  on support
 of the number in  the population also can arise.
   Let the population under consideration consist (as
 in the preceding example) of two phenotypes de-
 termined by one  gene with dominant (A) and re-
 cessive (a) alleles.
   Let us also assume that two reproduction  cycles
 take place  during a  season, and let us, for purposes
 of simplicity, assume that each generation reproduces
 but once. The generation born during the second re-
 production cycle  will not reproduce in this same
 year, and the part of this generation that overwinters
 is the  first of the reproducing group the following
   Let «! be the mean number of descendants  among
 the specimens with  genotype  AA  and  Aa, and  o2
 = /fai (/?>!) be the  mean number of descendants of
 the specimens with genotype aa.
   Let us make the further assumption that there will
 be no deaths among those specimens in the popula-
 tion that do not reproduce during the summertime,
 and that  during the  fall and winter A, percent of the
 number of specimens with genotypes AA and Aa,
 and A2 percent of  the number of specimens  with
 genotype aa, will  die; O^A^A^l.
   Accordingly, the   specimens with genotypes AA
 and Aa (let us call them the "winter" specimens)
 have a relatively low fertifility rate, but tolerate the
 fall and  winter better.  Those specimens with the
 "summer" genotype  aa are more  fertile,  but  at the
same  time  are  more sensitive  to  environmental
   We shall here, as in the preceding model, take it
 that panmixia takes place in the population.
   Now let X, Y, and Z be the numbers of specimens
 with genotypes AA, Aa, and aa, respectively. N = X
 + Y + Z is the total number of the population, and
        x = X/N, y = Y/N, z = Z/N
 are  the percentages  of the corresponding genotypes.
   The vector (X, Y, Z) determines the structure of
 the population at each moment in  time. If the entire
 generation lives until the next propagation period the
 structure of the  succeeding generation can be  de-
 termined by the operator T
          T(X, Y,Z) = (X',Y',Z')
        Z' =
    (ou/2 Y+a2Z)(Z+l/2Y)
                N           J
            + (ai/2 Y+a2Z)(X+l/2 Y)
                         N              '
   Let us further assume that
     S(X, Y, Z) = [(1-\1)X, (1-A,)Y, (l-x2)Z].
   Then  the population with the structure (X, Y, Z)
 at the beginning of the summer will have the  struc-
        (ST2)  (X, Y, Z) = (X,, Yj, Z,)
 at the beginning of the next summer.
   It can safely be pointed out that the corresponding
 transformation of the variables (x, y, z) (for which
 x + y + z = l) is completely determined by their values
 (that is, it does  not depend on N).  The analytical
 form of the representation  of  the  triangle used  in
 this case is much more complex than  in the conven-
 tional  iterations of  quadratic   representations  in
 mathematical genetics (see reference [8]). Formally,
 the reason for this fact reduces to this. One is forced
 to make a certain normalization,  as distinct from a
 purely genetic situation,  in  which  the  sum of the
 coordinates  can  be preserved automatically (even if
 panmixia is  lacking)  in order to retain the condition
 that x + y + z= 1  because of the differences in fertility
 and mortality  among the different genotypes.
   Obviously then, a  pure  population consisting only
 of specimens with genotype  AA will  survive if

        a12(l-X,)>l.               (7)

   Analogously,  a pure "summer"  population will
 survive when
  We shall demonstrate the fact that a mixed popula-
tion, in which "winter" and  "summer" specimens
are  present, will survive in the case of certain values

of the  parameters «i, <*2, Xi, X2, that satisfy neither
of the inequalities at (7) and (8).
  We should point out that in the model under con-
sideration the dependence of fertility on  density has
been omitted for reasons of simplicity. However, if
this dependence is introduced, as was done in the
preceding model, similar effects  will occur here  as
  We  have made  yet  another  simplification, one
that allows us to avoid  making cumbersome calcu-
lations. To that end, let us assume  that X2 = l (the
"summer" specimens all  die during the winter). This
of course is  not compatible with the inequality at
(8), so in this  case it is convenient  to use the vari-
ables N andij=y/2.
   Let  us put ai = a, X!  = A,  a2 = )3a. Direct calcula-
tions  will lead  to  the  following relationship,  one
determining population  dynamics during the year
                = (l-X)Na2(l
   The value ?/=0 is a fixed  point on the represen-
 tation of the segment [0, Vi] itself, found by using
Eq. (10). This point is stable when /3<3, with the
result that  in  a mixed  population of heterozygous
specimens  (and,  consequently, the  percentage  of
summer specimens that appear during the  season)
it vanishes. In this case the conditions for the sur-
vival of the mixed population are given by  the in-
equality at (7), just as was  the  case for the pure
  However, when /? > 3, the point ^=0 will be-
come unstable,  and another stable, fixed  point  i?
= (/8-3)/2(/3-l), will appear (see Figure 2).
  What this means is  that each spring the popula-
tion will contain a definite percentage of heterozygous
specimens, so  that summer specimens will appear in
the course of  the reproduction season, and will re-
produce. These specimens represent a not inconsid-
erable  part of the population. The condition for the
survival of a mixed population, readily obtained from
the inequity Na(N, ijT^N, has the following form
when /8>3
                                                    Thus, if for given a and 0
                                                                                I +
                                                                                   (0 - 3V
                 1-X      L    8(0-lV
 the pure "winter"  population will  die out,  but the
 mixed population will not! (Let us recall that the
 pure "summer" population too will die out,  because
                                 FIGURE 2.  POPULATION DYNAMICS

   The  coefficient  l + 08-3)2/8(/3-l)  measures
 the advantage in viability imparted by polymorphism.
   Let us use a numerical example that  will show
 quite graphically the population dynamics in this
 case to illustrate our conclusions.
   Let a = 2, 0 = 5  (that is, a2 = 10), A = 7/9. In this
 case /t0 = Vi. Let us set X = Y = 100.
t + 2
                       1 year
   For purposes of comparison with a pure
   We have selected limit X values for which the in-
 equality at (11) will be transformed into an equal-
 ity,  despite the fact that from the standpoint of our
 model this is an exceptional case,  in  that a  small
 change in  A will  lead to dying out, or to exponential
 growth of N and to increasing oscillations in the
 magnitudes X, Y, Z. However, this  behavior will be
 typical of  a model in which fertility is a function of
   We shall conclude  our discussion of this model
 with a few remarks. Along with  the simplifications
 already mentioned, we have assumed that one gene
 has  a simultaneous influence on fertility and sur-
 vivability  under  severe  environmental conditions.
 This assumption would not appear to be very  natu-
 ral at first glance. However, it can be supposed that
 the  "winter"  and "summer" species  can be dis-
 tinguished by metabolic intensity,  the  consequence
 of which is a longer period of sexual maturation and
 a longer life span among the "winter" specimens.
   Here consideration must be given to  the fact that
 the  greater fertility of the  "summer" specimens is
 the  result  of their  success in reproducing a greater
 number of times.
   A scheme such as this can be realized in a model
 if, needless to say, the number of reproduction cycles
 per season is increased (for the "summer" specimens
 at the very least). Another extremely interesting di-
 rection is  associated  with  study  of the oscillations
 that  take place in the genetic structure in a popula-
 tion  of long-lived organisms (see reference  [9]).
  4. The final subject we shall touch upon in this
 report is the effect man has on a population as it is
 exploited; that is, by the withdrawal of some of the
 specimens  from  the population.  The practical im-
 portance of this  subject is obvious, and  its  study
 covers a considerable part of mathematical ecology
 (see the  well-known book by K.  Uatt [10], for ex-
 ample, in  which the  author concentrates on the
question of the effect exploitation has on a popula-
   We should  like to turn our attention to the con-
nection that exists between  the subject of optimum
exploitation of a population and the principal theo-
rems in mathematical economics.
   Let us consider the following model.  Let a popula-
tion consist of N+1  mature  groups. Let us designate
the number in the ith group by m, i = 0,  1,  	  N.
Fi is the mean number of offspring per unit time for
the specimens in the itb group, pi  is the probability
that specimens aged i will  live to age i+1  under
natural conditions (no exploitation).
   Let us,  in addition, introduce the index Wi, the
exploitational worth  of the specimen.
   Let us give our external effect on the population
(or control) by the vector (uc, u,, ..... UN), where ui
is  the percentage  of the ilh group meaningfully with-
drawn from the  population (for the time segment
under consideration).
   We must,  in order to establish population and
harvest dynamics, stipulate the moment in time when
the harvest must be removed (this need not be done
if a continuous time model is considered).
   If the  harvest is removed at the beginning of the
period we shall call the  corresponding  model model
A. It has the form
                                                    The harvest is equal to
                                             V     ui
                                          =  )   ,— v
                                             I— I   l-U.     1
                                                                    1 = 0
                                                    (Wi can obviously be equated to the beginning of the
                                                    period as well.)
                                                      If we remove the harvest at the end of the period
                                                    (and after taking  the effect of natural mortality into
                                                    consideration), we shall call the corresponding model
                                                    model B.
                                                            j\\ =(1 -ui.1)pMn..1,i
                                                    The harvest is equal to
                                                             ui-iPi-lni-iWi-j - 2, uiPi

(Wi in  this case can be equated to the end of the
  We shall, for purposes of definiteness, henceforth
consider the type A model.
  The problem, in the most general of terms, is that
of constructing that sequence u(1), u(2), ..... of equa-
tions that will maximize the harvest.
  We have to know the factors upon which the dy-
namics  of the  number in a population depends in
order to state the problem more precisely  (density,
nutrition, and the like).
  It can be taken, for example,  that the parameters
Fi, pi, Wi depend on n in such a way that an increase
in n will reduce their values.
  Another approach  is that there is some  set of
reserves and that a limitation  of the  following type
can  be  satisfied
        on  is the  consumption  of  reserve  j by one
          specimen in the ith group;
        Fi, pi, Wi are constants that still satisfy the
          limitation at (15).
   Then we must clearly distinguish what  it is that
we take as the criteria. If expenditures required  to
remove  the  harvest  are ignored,  we can, for ex-
ample, maximum the summed harvest over a long
period of time.
   We should point out that we must, naturally, limit
those controls that depend solely on the present state
of the system.
   Employing the considerations that can be used for
the proofs of the so-called theorems of main lines  in
consumption (see reference [11],  Chapter IV), we
can prove  the following. There  exists that temporally
independent  steady-state equation u = u0,  ui . .  . ,
UN_]( and the vector n, invariant with respect to this
equation,  that  is, satisfying the condition  set  forth
at  (16)
 and any optimum trajectory of length T always will
 reduce to a small neighborhood of state n, except for
 the  end segments at the beginning and at the end,
where the controls used at this time are close to con-
trol u. We will not, here, discuss in detail the occur-
rence of the  analogy between the economic and the
ecological magnitudes. We shall simply note that the
limitations of (15) play the same role that the exoge-
nous  reserves play in an  economic system; that is,
those reserves  the  system itself does not  condition
(manpower,  for example).
   The  considerations  cited, which are  new  only
in part, have been advanced as a result of discussions
between the  participants in the group engaged in the
mathematical modeling of ecological systems in the
Laboratory of Functional Analysis and Models of
Economic Dynamics at the TsEMI [expansion un-
known]  of the Academy of Sciences of the USSR.
The group includes M. Ya. Antonovskiy, V. I. Dani-
lov, V. A. Iskovskikh, and A. B. Katok.
   Academician S.S. Shvarts raised for our  group
questions concerned with the interaction of ecologi-
cal and genetic factors. The phenomena he pointed
out are at the basis of the mathematical models con-
sidered in paragraph 3.
   Discussions of the questions related to  the influ-
ence  of density on population dynamics  with our
coworkers at the Institute of the  Ecology of Plants
and  Animals  of the Academy of Sciences of  the
USSR, and with V. S. Smirnov, and V. G. Ishchenko
in particular, were extremely useful.

                                                    1. A. N. Kolmogorov. "Qualitative Investigation of Math-
                                                      ematical  Models  of  Population Dynamics." Problemy
                                                      kibernetiki, No. 25, 1972. pp. 100-106.
                                                   2. H. G. Andrewartha, L. C. Birch. The Distribution and
                                                      Abundance of Animals.  The  University of Chicago
                                                      Press, Chicago, 1954.
                                                   3. E.  Makfed'yen. Ekologiya zhibotnykh [The Ecology of
                                                      Animals]. "Mir" Publishing House, Moscow, 1965.
                                                   4. V. L. Andreyev, A. A. Nagorskiy, A. P. Shapiro. "Mod-
                                                      eling a Fish Population With a Two-Year Life Cycle
                                                      and a Single Spawning." Problemy kibernetiki, No. 25,
                                                      1972. pp. 167-176.
                                                   5, H. D. Ford, E. B. Ford.  "Fluctuation in Numbers and
                                                      Its Influence  on  Variation in  Melitea Aurinia."  Jor.
                                                      Trans, Royal Ent. Soc., London, Vol. 78, 1930.
                                                   6. S. M. Gershenzon. "Seasonal Changes in the Frequency
                                                      of the Occurrence of Black Hamsters." DAN SSSR, Vol.
                                                      43, No. 9, 1945.
                                                   7. S.  S. Shvarts.  Osnovy  evolyutsionnoy ckologii  zhivot-
                                                      nykh [Fundamentals of  the  Evolutionary Ecology of
                                                      Animals]. Sverdlovsk, 1969.
                                                   8. F. Frank. "The Causality of Microtime Cycles in  Ger-
                                                      many.'';. Wildlife Mgt., 21, 113-121 (1957).
                                                   9. S.  S. Shvarts, V.  G. Ishchenko. "Dynamics of the Ge-
                                                      netic Composition of a Population of Rana terrtstris."
                                                      Byulleten' Moskovskogo obshchestva ispytateley prirody.
                                                      Old. biologii., Vol. 83,  No. 3, 1968. pp.  127-133.
                                                   10. K. Uatt. Ekologiya i upravleniye prirodnymi resursami
                                                      [Ecology and Control of Natural Resources],  "Mir"
                                                      Publishing House, Moscow, 1971.
                                                   11. Kb. Nikaydo. Vypuklyye struktury i matematicheskaya
                                                      ekonomika [Convex Structures and Mathematical Eco-
                                                      nomics], "Mir" Publishing House, Moscow, 1972.

                      Global  Climate  and Human  Activity
                                 M. I. Budyko,* I. L. Karol *
1. Models of Changes in Global Climate

  Previous  investigations  (Budyko,  1969,  1971,
1972; SMIC 1971, and others)  have shown that
modern economic activity already has had a marked
influence on global climatic conditions, and this in-
fluence is increasing rapidly.
  This fact has given rise to the  important task of
estimating  possible  climatic changes  in the  future
for different conditions of further economic develop-
  The only way  to accomplish this task is to use
numerical  models of  climate  theory  to determine
changes in meteorological conditions.
  Models of a climate investigated for purposes of
studying its possible  future changes  should  satisfy
certain  requirements,  but  these latter are  less im-
portant for models used  in investigations of the pres-
ent day climate.
  The model ought not include  empirical  data on
the distribution of individual climatic elements,  es-
pecially  those  which  change   significantly  with
changes in climate.
  The model should take into consideration all types
of heat flows with a marked effect on the tempera-
ture field, and the law of the conservation of  energy
should be satisfied.
   Climate is formed by:
   1.  the distribution of radiation  in the atmosphere;
   2.  the transfer of heat and moisture by the move-
ments of  the atmosphere and ocean;
   3.  the hydrology of the underlying  surface  (it has
a greater  influence on the local climate of the lower
troposphere, and is not considered here).
   The  heat balance equation
                 Q(1-A)-I = F,            (1)
links the flow of heat from the sun's shortwave radia-
tion, Q (A is the albedo of the  earth-atmosphere
system), the infrared (IR)  radiation  of heat, I, for
this system, and  the heat transfer, F, by the move-
ments of the atmosphere and ocean, as basic factors.
These factors  depend significantly  on the following
parameters (Budyko, 1971): A,  the albedo of the
earth-atmosphere system, increases sharply  over  (a)
 a snow and ice surface, (b) clouds (especially dense

  •Main Oeophyiical Laboratory, Leningrad
clouds),  (c) without clouds somewhat more over
land bare of vegetation than over the sea.
  The following also have a great effect on the dis-
tribution of radiation in the atmosphere: (a) clouds
and water vapor absorbing and scattering short- and
longwave radiation; (b) dust, doing the same to the
sun's shortwave radiation; (c) carbon dioxide, CO2,
which absorbs IR radiation;  (d) ozone,  O3, which
heavly absorbs the sun's ultraviolet (UV)  radiation.
  Global movements of the  atmosphere are deter-
mined by the planetary distributions of its tempera-
ture and humidity and,  in turn, form them. Their
intensity depends primarily on the difference in tem-
peratures at the equator and at the poles, and be-
tween the  continents and  oceans. The relationship
between the nature and intensity of ocean currents
and external conditions is more complex.  It is only
partially linked with  atmospheric circulation.
   These climatic factors are linked by the following
positive  and negative feedback rings.
   1. Polar  ice,  almost doubling A, reduces the air
temperature, T,  and thus promotes its  own distribu-
tion. This is a positive feedback ring, which exerts
a great influence on the distribution of T (Budyko,
   2. Clouds,  generally speaking,  reduce the radia-
tion passing to the earth, and reduce T, and evapora-
tion, E, which leads to a reduction in cloud cover.
This is a negative feedback ring. But they do inhibit
IR radiation and block and radiation reduction in T.
This is a positive feedback ring.
   3. Increase in absolute humidity with increase in
 T leads to the absorption  of longwave radiation  by
the  atmosphere  and  to its heating. This is a positive
 feedback ring.
   4. Increase in T increases the intensity of the  at-
 mosphere's IR radiation. This is a negative feedback
   5. Increase in the CO, in the atmosphere reduces
 the intensity of its absorption by the ocean, given a
 rise in temperature  and in the acidity of the waters
 of the latter. This leads to an even greater accumula-
 tion of CO2 in the atmosphere, and is a positive feed-
 back ring  (Machta, 1973).

   6. The intensity of heat and moisture transfer de-
 creases with warming of the polar atmosphere, and
 so does the transfer of heat from the equator to the
 poles. This is a negative feedback ring.
   Negative circulation  rings increase  climatic sta-
 bility; positive ones decrease it.
   The parameters of virtually all of these feedback
 rings have not yet been adequately studied, and it is
 possible that  other feedback rings exist, but if they
 do they are not significant.
   Man can affect climate in the following ways.
   (1)  A change in the components of the heat bal-
 ance of the underlying surface, of a city, a reservoir,
 irrigation of fields and of  agricultural land, is  the
 most  noticeable,   and  comparatively   well-studied
 change in climate, but is only local, and in the  lower
   (2)  The emission  of heat  into the atmosphere
 even now is changing local climate in  cities ("heat
 islands" in the center of a  city). When the current
 rate of growth  in the world's energy  requirements
 (about 6%  a year) is extrapolated, the  magnitude of
 this  emission  in the 21st century will become  com-
 parable to the magnitudes of the components of the
 heat balance for the  underlying surface, particularly
 in urban and industrial agglomerations  (Budyko,
   (3)  The increase  in the CO2 in the atmosphere
 attributable to the combustion of fossil fuel in recent
 decades is 0.2% per year (Machta, 1973). Accord-
 ing to the estimates contained  in this reference,  the
 mean  concentration  of  CO2 in  the  atmosphere in
 1860, was  approximately 10%  lower, and in  the
 year 2000, will be 15-20% higher, than its current
   (4)  The increase  in  the content of atmospheric
 aerosols. Stratospheric aerosols on  the whole reduce
 solar radiation incoming to the  lower atmosphere
 and  the underlying surface.  Heating of the strato-
 sphere by radiation absorbed by these  aerosols has
 almost no influence on the temperature  of  the tropo-
 sphere, and thus as a practical matter reduces the
 meteorological solar  constant (Kondrat'yev, et al.,
   The effect of  tropospheric aerosols is more  com-
 plex.  They  scatter and absorb radiation,  and this
 respectively increases and decreases the albedo (A)
 of the "earth-atmosphere" system. This  change in A
 depends on  the effective albedo of the  aerosols, A*,
 and on the albedo of the underlying  surface, A.. If
 A. is  small,  and if AsA»  (over snow and clouds), then
 an increase in C reduces A, and increases  T. A. de-
pends  on the aerosol's  optical  properties  and can
change  greatly in  different regions, and in different
 seasons, but as a mean, Aa is close to the mean for
 A» in  the  absence  of clouds, snow,  and ice  (Kon-
 drat'yet, et al., 1973). Aerosols under a cloud layer
 have little influence on the  radiation flux near  the
   Aerosols of anthropogenic origin now comprise
 10-20% of the total mass of atmospheric aerosols.
 There  are  predictions that suggest a doubling  of this
 percentage by the year 2000, if special measures are
 not taken to reduce the emission  of aerosols into the
 atmosphere by man (SMIC,  1971).
   (5) Mass flights of aircraft at a level of about 20
 km can result in the accumulation in the stratosphere
 of  the combustion products exhausted from their
 engines,  in a decrease in the  ozone content by inter-
 action with the nitrogen oxides they emit, and in an
 increase in stratospheric aerosols (Grobecker, 1973).
 The possible effect  of these aerosols on climate was
 indicated above, and  a  reduction  in the ozone layer
 will lead to an increase  in the biological danger from
 the sun's UV radiation. A change in the ozone con-
 tent can  change the climate in the stratosphere (es-
 pecially its circulation), because the absorption of
 solar radiation by ozone to a  considerable degree de-
 termines the heating and temperature of the  strato-
   Various  assumptions  can be made with respect to
 each of these factors,  on how each will change in the
 future  as further economic development takes place.
 The task of climatological investigations is to esti-
 mate  climatic  conditions  for  possible  variants of
 change in these factors. The question of the reliability
 of estimates of these changes is  worthy of  serious
 attention because of  the great practical  importance
 of global climatic changes.
   Two different approaches  can  be used in consid-
 ering this question.  The first  involves the verification
 of the  numerical models used for calculating the cli-
 mate of the future  using empirical data  on climatic
 changes in  the past. This approach was used in pre-
 vious work by one of the authors (Budyko,  1971,
 1972, and  others).
   The second approach is based on a comparison
 of the  results  of calculations of  climatic  conditions
of the  future, using different, independently  devel-
oped, models  of climatic theory.  The feasibility of
 using this approach appeared recently as a result of
the making of a series of investigations of anthropo-
genic climatic changes.
   Let  us consider  the results of  calculations  of the
influence of increasing the production of energy on
climate,  made using  various  models  of  climatic
  Washington  (1971)   used  a  three-dimensional
model  of climatic theory to calculate the change in
the air temperature field in  the  troposphere as the
result of an additional heat inflow  of 50 cal/cm2/day,
equally distributed over  the surface of the continents.

The mean air temperature in this case rose from 1 °
to 2°  C in the tropics, and from 8° to 10° C in the
higher latitudes of the northern hemisphere.
   A calculation using a semiempirical model of cli-
matic theory (Budyko,  1969) yields approximately
the same increase in the mean global temperature  of
3° C  for these  conditions (note  that in neither case
was  the dependence  of the   albedo of  the earth-
atmosphere  system on  temperature changes  taken
into consideration).
   Estimates of change  in the carbon dioxide  con-
centration with  thermal conditions in the atmosphere
were made in our paper (Budyko, 1973)  and in that
by Manabe (SMIC, 1971; Smagorinsky, 1974).
   Let us note that the feedback between changes in
thermal conditions in the atmosphere and  the posi-
tion of  the snow  and ice cap were taken into con-
sideration in all these studies.
   A comparison of the results of the calculation of
the effect of doubling the concentration of  carbon
dioxide  on  the mean  latitudinal  air  temperature,
made using our semiempirical climatic  theory, and
the general climatic theory used by Manabe, shows
good  agreement between the estimates  of the in-
fluence  of change in carbon dioxide concentration  on
climate  obtained using the different models.  Hence,
it follows that in such case the mean air temperature
increases by 2°-3° C in the low latitudes, and by  up
to 10°  C in the high latitudes.
   The  question of the influence of an  aerosol  on
thermal conditions in the atmosphere has  been dis-
cussed in numerous studies. It is determined by the
radiation flux in the atmosphere as a function of the
aerosol  concentration, and by  the air temperature as
a function of changes in shortwave radiation flux.
   Leaving the  first part  of this link aside for the
moment, let us  consider the results of the calculations
of air temperature as a function of the inflow of solar
radiation. These  calculations  have  been made re-
peatedly for different models of climatic theory with-
out taking into consideration  the feedback between
thermal conditions in the atmosphere and polar ice.
   This  feedback was taken  into  consideration for
the first time within the framework of a semiempiri-
cal model of climatic theory  (Budyko,  1969). This
study established that the mean air temperature at
the earth's surface changes sharply with small fluc-
tuations in the solar constant, and that a  reduction
of approximately 2%  in  the solar constant will  re-
sult  in  complete  glaciation of the  earth. A similar
conclusion was obtained as a result of the develop-
ment of a series of different semiempirical models of
thermal conditions in  the atmosphere, including con-
sideration of the  feedback indicated above (Sellers,
1969; Schneider and Gal-Chen, 1973).
   The  conclusion drawn with respect  to the high
degree  of the sensitivity position of the polar ice to
small changes in  the inflow of solar energy resulted
in obtaining a quantitative explanation of the process
of the development of quaternary glaciation (Budyko
and Vasishcheva,  1971; Berger,  1973).
  The question of air  temperature as a function of
the solar constant  was studied in the last  papers
written   by Manabe  (Smagorinsky,  1974)  who
used general climatic  theory  and included consid-
eration of the feedback between thermal  conditions
and the snow and ice cap. Here, it was found that a
2% increase in the solar constant resulted in a 1.2°
C mean change in the  air temperature for the hemi-
sphere, according to the Manabe and Vezerold  local
model of thermal conditions when changes in abso-
lute air humidity were disregarded. The change was
2.4° when  absolute air  humidity  as a function of
temperature was included and the same model was
used, but was 3.1° C when Manabe's model  of gen-
eral climatic theory  was used. The latter  magnitude
differs comparatively  little from the result  of the
analogous  calculation  made  using the above-men-
tioned semiempirical model of the thermal conditions
in the atmosphere,  from which it follows that the
indicated increase  in temperature is 4.5° C.
   In estimating the  magnitude of the relative reduc-
tion in  the solar  constant  sufficient to  completely
glaciate  the planet,  Manabe, as well as the  authors
of the semiempirical studies, found it comparatively
small, and approximately equal to 4%.
   Thus, a great many studies based on  the use of
totally different models  of climatic  theory  produce
what are comparatively close  estimates of the influ-
ence  of  a  change  in climate-forming factors on cli-
mate. This permits  us to use these models with a
known  degree  of  confidence in making calculations
of climate  changes that could result  from the devel-
opment  of economic activity.

2.  Changes in Climate by the End of the 20th
   Let us  examine the climatic changes  that could
take place by the  end of our century as  a result of
anthropogenic  factors. Calculations  suggest that  in-
crease in energy production (by approximately 6%
a year)  will have  no significant influence  on climate
before the end of  the 20th century, although this in-
fluence could be very  substantial over the next cen-
tury  (Budyko, 1972).
   Calculations of the  influence of aerosols  on ther-
mal conditions in  the atmosphere  are  difficult  to
make because of the lack of data on the mean values
of  the  parameters of  the models used, particularly
as  the  data pertain to the coefficients of radiation
absorption by aerosol  particles. Here it is that anal-
ysis of  empirical data is of considerable  importance
in estimating the influence of an aerosol on radiation
and thermal conditions.
   The  data from observations made by  a group of
actinometric stations in Europe, Asia,  and  America

 were processed by Z. I. Pivovarova and the results
 were used to chart the secular course of direct solar
 radiation in  a cloudless sky over the past decade for
 purposes of  estimating the influence of an anthropo-
 genic  aerosol  on climate (Budyko and  Vinnikov,
 1973). The  conclusion reached as a result  of this
 investigation was that anthropogenic aerosols have
 in recent years reduced direct radiation in a cloudless
 sky by approximately 6%, and the summed radia-
 tion for average conditions by approximately 0.5%.
   The use of  the Yamamoto and  Tanaka (1972)
 model, in which  the influence  of aerosol on back-
 scattering and  radiation  absorption  is  taken  into
 consideration, resulted in the  finding that this reduc-
 tion in radiation  corresponds to a  reduction in  the
 mean  air temperature at the earth's surface  of  ap-
 proximately  0.5° C.
   Although, as noted in this study, this  estimate is
 very approximate in  nature,  it can  be assumed that
 further rise in  the aerosol concentration can lead to
 a significant  change in climate.  However,  it is quite
 difficult to predict the future quantity of atmospheric
   We can assume that failure to combat atmospheric
 pollution will result  in the ratio of increase  in  the
 anthropogenic aerosol mass to its current value being
 equal  to  the analogous value for the anthropogenic
 carbon dioxide  mass in the atmosphere.  Given this
 assumption,  the quantity  of  anthropogenic aerosol
 can increase  by a factor of 2.5 to 3 by the year 2000.
 But because  many countries are taking steps to re-
 duce atmospheric pollution, the increase in the quan-
 tity of anthropogenic aerosols will  come  to a halt,
 and their quantity by the end of the century will re-
 main  at  the  current level, or  may even decrease.
 Given these conditions, increase in the carbon dioxide
 concentration, leading to a warming trend, will exert
 the major influence on change in climate.
  A variety of  models of climatic theory can be used
 to estimate this warming trend.  What follows from
 the above-cited Manabe and  Vezerold local  model
 of climatic theory is that  a 20% increase  in carbon
 dioxide concentration will increase the mean  global
 air  temperature 0.5°. Manabe's  calculations, based
 on  the use of a three-dimensional model  of general
 climatic  theory,  showed a 0.7° C  increase  in the
 mean global  temperature for this case, and approxi-
 mately twice  that for the high latitudes.
  A  similar calculation,  using  our  semiempirical
 model of thermal conditions  in  the  atmosphere and
 the relationship between  air  temperature and car-
 bon  dioxide  concentration according  to  Rakipova-
 Vishnyakova, and given the assumption of the quasi-
stationary state of polar  ice  (see  Budyko,  1972),
 showed a 0.6° C increase in temperature,  and, given
the  assumption of stationary ice conditions, 0.9° C.
As  we  see, there is  little  difference between these
   Calculations using a semiempirical model of ther-
 mal conditions in the atmosphere show that the area
 of sea ice in the northern hemisphere can be reduced
 by  10 to 20 percent by an increase of 0.5° to 1 ° C in
 the  mean  global temperature. This will be accom-
 panied by a several degree increase in temperature
 during the winter in  the  high  latitudes, something
 that can  greatly influence Arctic navigation condi-
 tions,  as well as many branches  of the national econ-
 omy in the northern regions.
   Fluctuations in  the amount  of precipitation that
 falls, associated with change  in thermal conditions,
 can be of even greater  practical  importance.  The
 overall warming  trend can  be accompanied  by  a
 reduction in the mean meridional  temperature gra-
 dient,  because  the air temperature in the  high lati-
 tudes rises much more than it does in the  low lati-
 tudes with increase in the carbon dioxide concentra-
 tion. As  is  known, changes  in this gradient have
 very definite influence  on the intensity  of  zonal
  A series of empirical studies  (Budyko and Vinni-
 kov, 1973, and others) has established the  fact that
 there is a signicant relationship between the precip-
 itation  falling  on continents  and  relatively  small
 changes in the mean meridional temperature gradient.
 Reductions in this gradient that took place, for ex-
 ample, during the warming trend of the 1920's and
 1930's, were accompanied by a considerable reduc-
 tion in precipitation in many  intracontinental areas.
 This led to a substantial  increase in the number of
 droughts covering large areas in the USSR, USA, and
 other countries, to a drop in  the  level of many in-
 ternal  water expanses, including  the Caspian  Sea,
 and to a number of other consequences.
  Change  in climatic  conditions that can occur by
 the end of the 20th century as a result of increase in
 the carbon dioxide concentration will greatly exceed
 the  warming trend of the 1920's  and  1930's, and
 could have a great influence on agricultural produc-
 tivity. The need for a more detailed study of anthro-
 pogenic changes in climate, using models of the dy-
 namics of  the atmosphere and  oceans, and created
 just  to study  possible changes  in climate, therefore is
 obvious.  These  models  should be nonstationary,
 quite detailed, yet not too cumbersome. Calculations
 of many variants of change in  global climate, decade
 by decade, then could be  made by  using them and
 modern computers. These calculations could take
 into consideration  the influence of  the oceans and
 polar ice,  as well as various assumptions as  to man's
 future  effect on specific climatic factors.  There should
 be several such models, all incorporating the various
 assumptions,   and  coordination  of  estimates   of
 changes in climate, calculated  using them, would en-
 able us to  establish the reliability of these estimates
 and  models.  Coordination of  international  scientific
efforts in this field is very important.

  Calculations using these models will enable us to
find the levels, and growth rates, of the anthropogenic
effect on global climate that will not exceed the nat-
ural  variation in  the scale of the warming trend of
the 1930-1940 period by the end of the 20th century.
  There  can be no doubt of the great importance of
those data for planning the optimum interaction be-
tween society and the environment,

3. Controlled Effect on Global Climate
  One approach this effect can take in order to pre-
vent undesirable changes in climate is based on  an
artificial  change in the concentration of aerosol par-
ticles in the lower stratosphere  (Budyko, 1974).
  The nature of an aerosol in the lower layers of the
stratosphere  was  studied by Junge (1963), Cadle
(1972),  and others, who established that there is a
layer of particles, the mean size of which is measured
in tenths of  a micron, in  the lower stratosphere. The
heaviest  concentration of particles  usually will  be
observed in  a layer about 2 km thick at a height of
18-20 km.
  The particles in the stratosphere's  aerosol layer
are mostly  sulfur compounds. Junge hypothesized
that  these particles are formed from sulfur dioxide
(SO2) which,  oxidizing  during  photochemical re-
actions, is converted into sulfur trioxide  (SO3), and
with water  vapor forms dorplets  of  surfuric  acid
(H2SO4), which  comprises the major part of the
aerosol in the lower stratosphere (SMIC, 1971).
  Aerosol particles are retained in the stratosphere
for a long time with the  average from 1 to 3 years.
The  mechanism involved in their precipitation,  ap-
parently,  is   connected with their  coagulation and
increase  in  size.  The  very slow movement of  the
particles  in the vertical direction contrasts with their
extremely rapid transfer  along the  horizontal. Ob-
servation of the distribution of particles in the strato-
sphere after  volcanic  eruptions shows that when  an
eruption  occurs in the extra-tropical  latitudes,  the
particles   are spread  over the  entire  hemisphere
within a  few months by stratospheric winds. The
particles  are distributed over both hemispheres with-
in this same  time frame if the eruption occurs in the
equatorial zone.
  According to observational data, aerosol  particle
concentration can change over broad limits. Accord-
ing to Junge's observations  in  1961, for example,
the concentration  was of the order of magnitude of
0.01  jug/m3, and  had reached 0.20-0.30  /xg/m3 in
1968-69. This marked increase in the concentration
is explained  by the influence of the eruptions of the
Agung volcano, and  of  some  others.  In 1970, the
concentration of  aerosol  particles decreased to sev-
eral  hundredths of a ^g/m3.
  It  is  interesting to compare  aerosol  concentra-
tions for different years with the  magnitudes of
direct radiation in a cloudless sky for the correspond-
ing periods of time. Z. I. Pivovarova used data from
observations  made  by a group  of actinometric  sta-
tions in the USSR and USA to calculate mean direct
radiation  magnitudes.  These  were  found  to  be
equal to 98% of the norm  in 1961, to 93-94% in
1968-69, and to 97% in  1970. The definite con-
cordance between  changes in aerosol  concentration
and fluctuations in the direct radiation  magnitudes is
worthy  of attention. This makes it possible to take
the comparatively few changes in aerosol concen-
tration that are quite characteristic for the whole of
the northern  hemisphere into consideration.
   The  direct proportionality  between changes in
aerosol  concentration and changes  in  radiation  flux
follows  from  the theoretical  considerations. The data
cited in the  foregoing  then  show that a 0.06 /*g/m3
increase in the aerosol concentration reduces direct
radiation by  1%.
   This   significant  dependence  of  the  shortwave
radiation  flux on  the aerosol  concentration in the
stratosphere explains the marked influence of explo-
sive volcanic eruptions on  climatic  conditions.
   Actinometric observations have shown a marked
reduction in  direct radiation all over  the world, or
within the limits of one hemisphere, after explosive
eruptions. Direct radiation  decreased  by 6%  after
the eruption  of Agung volcano in 1963, and there
was an  even  greater reduction in radiation after the
eruption of Mount Katmai in 1912, when the reduc-
tion in  direct radiation was  22%  (Budyko,  1971).
   Fluctuations in direct radiation after volcanic erup-
tions are accompanied by changes in summed radia-
tion that make up a comparatively small part of the
magnitude of changes in direct  radiation. It can be
assumed that the influence of a reduction in summed
radiation  on  the temperature of the lower air layer
depends on how long the reduction in radiation lasts.
   Meteorological observation data show no marked
change  in the  temperature  near the earth's  surface
after the eruption of Agung volcano, but there  was
a  reduction of 0.5 °C,  on the average,  for the north-
ern hemisphere after the eruption of Mount Katmai.
A reduction  such  as  this in temperature  apparently
is a small part of  the change that  would occur in
the  event of a  prolonged  reduction in  radiation.
These data therefore suggest that the summed radia-
tion decreased by approximately 1%  after the first
eruption, and by 3%  after  the  second.
   The  thermal conditions involved in the "warming
of the Arctic" were much closer to  the steady state.
Direct  solar  radiation increased  by  approximately
2% in these years, and this increase continued for
almost  twenty years. An  increase  such as this in
direct radiation corresponds to a 0.3%  increase in
summed radiation. This should lead to  an approxi-
mate 0.45°C  rise  in planetary temperature at the
earth's  surface under  steady-state  conditions.  This

 latter value is only slightly  greater than the change
 in temperature established from observational data.
   Thus, the change in temperature in the lower air
 layer when there are fluctuations in  stratospheric
 transmittance depends on two factors: the magnitude
 of the change in the concentration of  aerosol par-
 ticles in the stratosphere; and the duration of this
   Let us examine the possibility of a change in cli-
 mate on the scales observed during the  "warming of
 the Arctic" period, but in the opposite direction; that
 is, providing for  a  reduction in the  mean tempera-
 ture  at the earth's surface. This would  mean a 2%
 reduction in the mean magnitude of the direct radia-
 tion, and this  corresponds to  a reduction of 0.3%
 in the summed radiation.
   We have already cited an  empirical  estimate of
 change in  radiation as  a function of aerosol con-
 centration in the  lower  stratosphere. Other calcula-
 tions  of this relationship, based  on empirical data
 and  on a  theoretical analysis, yield  a somewhat
 greater magnitude  of the  aerosol mass  changing
 shortwave radiation by the specified magnitude. The
 mean of all these calculations  of  the magnitude of
 the aerosol  mass changing summed radiation by 1 %,
 and the direct radiation by 6%, is close to 0.8 x 10-"
   A  close  look at this  estimate will show  that for
 the purpose indicated  above the aerosol mass in the
 northern hemisphere should be increased  by 600,000
   All that  has to be  done to  increase  the  mass of
 the particles measured in  the  lower stratosphere to
 this magnitude is  to deliver 200,000 tons of sulfur
 to the aerosol layer level, and this,  after combustion,
 will form 400,000 tons of sulfur dioxide. If  we con-
 sider that the mean life  span of aerosol  particles in
 the stratosphere is 2 years,  100,000 tons of sulfur
 annually would have  to be  delivered to the lower
 stratosphere in the northern  hemisphere in order
 to  create the  necessary  concentration  of particles
 consisting of pure sulfuric acid.
   The  combustion  in  the  stratosphere  of  much
 smaller quantities  of sulfur than this probably would
 actually be  sufficient to increase the mass of aerosol
 particles to 600,000 tons, because the  hygroscopic
 droplets  of sulfuric acid  will   absorb  water  vapor
 from  the air.
   The planning of such  effects requires accurate es-
 timates of  the  possible influence  on  stratospheric
 aerosols of  mass flights by supersonic  transport air-
 craft  in the  1980's, because their  influence can be
 considerable (Grobecker,  1973).  A  study  of the
 causes, and  of  the nature,  of natural fluctuations in
the content  of  these  aerosols  also is  needed for
their prediction and consideration when carrying out
the effects.
   Bringing  about  the  effects on climate  examined
above  will  prevent,  or weaken, the changes  in cli-

 mate  which could take place in 20-30 years as a
 result of the influence of economic  activity. But this
 effect is not the limit within reach  of modern tech-
 nology.  It  evidently will  be technically possible in
 the near future to affect the climate, creating changes
 in it that will  be greater  by an  order of magnitude
 than those that occurred in the climate in the 1920's-
 1930's;  that is,  ensuring  a few  degree reduction in
 global temperature. An effect on this scale could be
 necessary in the 21st century, when the temperature
 of the lower  layers of the  atmosphere could rise
 considerably as a result of a considerable growth in
 energy production.
   The question of the desirability of using  effects
 on climate  in the near future, when the influence of
 economic activity on  climate will be comparatively
 slight, deserves  study. Effects that will reduce the
 mean temperature several tenths of a degree will be
 economically desirable. Their use to change thermal
 conditions  will  have  little  influence  on economic
 activity, but an increase in the amount of precipita-
 tion can be of great  practical importance in many
 areas  of insufficient moisture.
   Let us note, in conclusion, that elucidation of the
 possibility,  in  principle,  of a  marked change  in
 global climate  by comparatively  simple means raises
 a  number of questions.
   Study  of these questions means  that  attention
 must  be given to the international  aspect  of the
 problem  of effect  on  climate.  Ye. K.  Fedorov
 (1958,  and others) indicated repeatedly  that the
 implementation of any major project affecting cli-
 mate is  possible only on  the basis of international
   The method of affecting  climate  that  we  have
 considered here will lead to change in climatic con-
 ditions in the territories of many countries, but the
 nature of these changes will be different in different
   This is what obviously makes  it desirable to con-
 clude  an international  agreement resolving the ac-
 complishment of effect on climate only on  the basis
 of projects  that have been examined  and approved
 by responsible international agencies, with the agree-
 ment of all  interested  countries.  Such an agreement
 should  encompass measures for guided effect on
 climate,  as well as those  types of economic activity
 similar to mass flights in the lower stratosphere, that
 could lead to unintentional changes in climatic con-
4.  Global Monitoring of Climatic Factors

  A global system of continuous  observations and
periodic  examination of the factors  forming global
climate, and its anthropogenic changes, is attracting
more and more attention from researchers as a com-
ponent part of global  monitoring of the environment.
The magnitudes  subject  to  global  monitoring,  the

basic approaches to its accomplishment, approximate
accuracies  and  frequency  of  measurements,  are
contained  in  the  well-known  SMIC  handbook,
1971, and  refined in the recently published Global
Monitoring Plan project (Munn, 1973). The global
monitoring of factors that have an effect on climate
is  the primary  goal of  the  recently organized  net-
work of World  Meteorological Organization stations
for measuring  background  atmospheric  pollution
(Munn, 1973).
   Continuous measurement and statistical process-
ing of primary  data  from  natural climate-forming
factors are needed for:
   1. direct and summed  solar radiation, measured
on a  standard  basis by a network of some 1,000
actinometric  stations,  located  in  all  geographical
regions,  but unevenly  (Budyko,  1971).  Most  of
these  stations did  not  begin operations until the
second half of  the 20th century, and their data are
as yet of little value in determining climatic changes;
   2. the albedo, the mean cloud cover, and the
mean limit of the polar  snow and ice cap. They are
most conveniently measured on  a  global  scale  with
standard  weather  satellite  equipment   (television
images)  (SMIC,  1971). Long series of comparable
data must  be collected  in  order to distinguish  per-
manent changes in magnitudes, because these meas-
urements have  only been made  systematically since
the end of the  1960's;
   3. the temperature of ocean surfaces, as mini-
mally characterizing thermal inertia and  heat trans-
fer in the oceans. SMIC (1971)  has pointed out the
inadequacy of the study thus far made of the energy
exchange between ocean and atmosphere, as well  as
the need for just  a rough working model of that ex-
change to define more precisely the magnitudes sub-
ject to global monitoring. The need for data on the
characteristics of the heat exchange that  takes place
between the surface and deep layers  of the ocean
and its surface  currents is obvious, but it still is im-
possible to obtain continuous data of this type  on a
global scale. The temperature of ocean surfaces can
be measured from satellites, given certain cloud con-
ditions  (SMIC, 1971).
   Certain  data on factors describing the state of the
climate, and on how man has transformed the under-
lying surface and thus has had an effect on climate,
must be obtained periodically, and in definite regions.
Included, for example,  are glacier  mass,  ocean level,
biomass of forests, area of  cities and artificial reser-
voirs,  and the  like. Table 7.7 (SMIC, 1971), lists
these factors  of the  "climatic  cadastre," the  peri-
odicity, and regions to be examined.
   The most important  of the anthropogenic factors
affecting climate  are continuous  measurements of  the
carbon dioxide and aerosols in the atmosphere. The
CO2  concentration undergoes little latitudinal and
seasonal changes, and its global distribution recently
was  studied in some detail (SMIC, 1971). These
changes  are  greater  in  the  northern  hemisphere,
where  the main  seasonally changing  sources  and
flows of  atmospheric  CO2  into  the  continental
biosphere are  located. Therefore, the  global  in-
crease  in the mean CO2 concentration  is  easy to
detect by taking measurements on small islands dis-
tant  from the continents,  or in the southern hemi-
sphere. The main sources  of anthropogenic CO2  are
in the  temperate northern latitudes, while  its oce-
anic flows and sources are in the polar and tropical
latitudes,  respectively. Measurements of  the meri-
dional  distribution  of the  surface concentration of
CO2 therefore are necessary by a network of points
from the north to the south polar area.  The  network
of WMO base stations for measuring background pol-
lutants  in  the  atmosphere is  distributed with this
special  requirement for station location  taken  into
   Attempts to estimate the summed annual anthro-
pogenic  emission of CO2 into the atmosphere, and
its increase in recent decades, were published  re-
cently (Keeling, 1973). A comparison between these
estimates and the measured increase in the content
of CO2  in the atmosphere possibly will permit re-
fining the rate at which absorption of CO2 by  the
ocean takes place, as well as how it has changed over
the years. The importance of  monitoring this value
is obvious, as is how it changes and depends on the
state of the ocean surface. We must, therefore, make
systematic measurements of the CO2 content in the
surface  waters of  the oceans in  different  latitudes
simultaneously with its content in the air above the
water, in order to estimate the rate of CO2 exchange
between ocean  and  atmosphere,  and to  study its
change.  The necessary frequency of these measure-
ments  in time and space still remains to be deter-
mined.  The establishment of  the physicochemical
causes of its change will be the primary goal of these
measurements and studies of the rate of CO2  ex-
   Global monitoring of atmospheric aerosols is more
complicated. The measurements of atmospheric  tur-
bidity  recommended and  made by the  network of
WMO stations are insufficient for distinguishing the
content  of  stratospheric  and  tropospheric  aerosols,
the  effect of which on climate, as indicated above,
differs  somewhat.  Individual,  systematic  (at  least
 once a  season) measurements of the content of aero-
 sols in  the stratosphere up to  the  30 km level, using
 aircraft and  balloons,  with  determination of the
 chemical composition of the aerosols, of the type of
 programs now conducted  in the USA therefore are
 needed  (Cadle,  1972).  These  measurements are
 particularly important after major volcanic eruptions.
 They  also  will be urgently needed to establish the
 possibility of global  regulation of the climate by the
 method proposed in paragraph 3.

   It is very difficult to establish permanent changes
in mean values on a global scale because of the great
changeability  and diversity  of the  aerosol concen-
trations in the troposphere, particularly  over areas
of intensive economic activity. Time-consuming proc-
essing of a great volume of data from a dense net-
work of stations is  required in order to obtain  re-
liable   statistical  characteristics.  Measurements  of
atmospheric turbidity, and analyses of filtered aero-
sol samples  obtained by  the network  of WMO  sta-
tions in terms of background  atmospheric  pollution
certainly will be inadequate  for this purpose.
   Ground measurements  of mean  global  levels of
the content  of aerosols in the troposphere can  be
made most conveniently in the polar region, for from
the main sources of anthropogenic and natural aero-
sols. Attempts are being made to estimate the  global
content of aerosols in the atmosphere from  measure-
ments in Antarctica and Greenland, as well as from
those made by research ships on  the high seas.
   Data on the intensity and special features of  global
transfer in  different parts  of  the  atmosphere  are
needed for these estimates, and can be obtained by
using tracers; radioactive, or those  like the  inert gas
freon-11   (a halogenated hydrocarbon, CC13F)  of
anthropogenic  origin, recently measured  by  a  re-
search  ship in the oceans  of the southern hemisphere
(Lovelock, 1973).
   Study and monitoring  of the global, more or  less
homogeneous, layer of aerosols in the middle,  and
particularly in the upper,  troposphere,  and which are
primarily of continental origin, also can be done  by
aircraft sounding in  the meridional  plane. The lower
level  of seasonal aircraft measurements  of  the con-
tent of stratospheric aerosols  indicated  above  can
be omitted for this purpose.
   Finally  (and this is  very  important),  detailed
climatological processing  and  analysis of  standard
meteorological  observations  (temperature  and pre-
cipitation  in  particular)  is necessary  to  distinguish
climatic fluctuations now,  and in  the near future, as
these investigations are continued for the end  of the
last century,  and the first half of this one  (Rubin-
shteyn, Ye.  S., 1973).
   All magnitudes  measured  should be associated as
much  as  possible with the  quantitative  models  of
global  climate  discussed  above. These magnitudes,
and the frequency and accuracy with which they are
measured,  should  meet the  requirements for  Initial
data, and should be capable  of being compared with
the resultant calculated climatic  parameters of  the

Budyko,  Mi.  I.,  1969,  Izmeneniya  klimata  [Climatic
  Changes], Gidrometizdat, Leningrad, 35 p.
Budyko, M. I.,  1971, Klimat i zhizri [Climate and Life],
  Gidrometeoizdat, Leningrad, 470 p.
Budyko, M. I., 1972, Vliyaniye cheloyeka na klimat [Man's
  Influence on Climate], Gidrometeoizdat, Leningrad, 47 p.
Budyko, M. I., 1973, Atmosfernaya uglekislota i klimat [At-
  mospheric Carbon Dioxide and Climate], Gidrometeoiz-
  dat, Leningrad, 32 p.
Budyko, M. I.,  1974, "An Approach to  Affecting Global
  Climate," Meteorologiya i gidrologiya, No. 2.
Budyko, M. I., Vasishcheva, M. A., 1971, "The Influence of
  Astronomical  Factors on Quarternary  Glaciation," Me-
  teorologiya i gidrologiya, No. 6, pp. 37-47.
Budyko, M. I., Vinnikov, K. Ya., 1973, "Modern Climatic
  Changes," Meteorologiya i gidrologiya, No. 9, pp. 3-13.
Kondrat'yey, K. Ya., et al., 1973, Vliyaniye aerozolya na
  perenos  izlucheniya:  vozmozhnyye klimaticheskiye  voz-
  deystviya  [The  Influence  of  Aerosols  on  Radiation
  Transfer: Possible Climatic Effects] Izd. LGU, 266 p.
Rubinshteyn, Ye. S., 1973, Struktura kolebaniy temperatury
  na severnom  polusharii [The  Structure of Temperature
  Fluctuations in the Northern Hemisphere], Gidrometeoiz-
  dat, Leningrad, 34 p.
Federov, Ye. K.,  1958, "The Effect of Man on Meteorologi-
  cal Processes," Voprosy filosofii, No. 4.
Berger, A. L.  1973. Theorie astronomique des paleoclimats,
  v. I, v.II, Louvain.
Cadle,  R.  D., 1972. Composition of the stratospheric "sul-
  phate layer,"  EOS. Trans. Amer.  Geoph. Union, v.  55,
  No. 9, 812.
Grobecker, A. J., 1973. United States  Department of Trans-
  portation. Research program  for  assessment  of strato-
  spheric pollution. DOT TST-2.1, Wash., D.C.  22 p.
Junge,  C.  E.,  1963. Air chemistry and radioactivity.  Acad.
Keeling, C. H., 1973. Industrial production of carbon diox-
  ide from fossil fuels and limestone. Tellus. v. 25, No. 2,
  p. 174-198.
Krey,  P. et al.,  1973, Project  Airstream.  Fallout program.
  Quart, summary report. HASL-276,  p. II-6—11-70.
Lovelock,  J. E.  et al., 1973. Halogenated hydrocarbons in
  and over the Atlantic. Nature, v. 241, No. 5386, p. 194-
Machta, L., 1973. Man's influence on the  climate. A status
  report. Lecture at the VI Session of Commiss. Atm. Sci.
Munn,  R.  E., 1973, Global environmental monitoring sys-
  tem.  Action Plan for  Phase  I. SCOPE  Rep. 3, Toronto.
Reiter,  E.  R.,  1971. Atmospheric transport processes. P. 2.
  Chemical tracers. U.S. A.E.C.  TID 25314,  Oak Ridge,
  382 p.
SMIC., 1971.  Inadvertent climate modification. MIT  Press,
  Cambr.,  Mass, and Lond. 306 p.
Schneider,  S.  H.  & Gal-Chen,  T., 1973. Numerical experi-
  ments in climate stability. Journ. Geoph. Res., v. 78, No.
  27, p. 6182-94.
Sellers, W. D., 1969. A  global climate model based on  the
  energy balance of the earth-atmosphere system. I.  Appl.
  Met., v.  8, No. 3, p. 392-400.
Smagorinsky,  J.,  1974.  Global atmospheric modeling and
  the numerical simulation of  climate. In Weather Modifi-
  cation. Ed. W. W. Hess, Wiley & S, N.Y.
Washington, W. M., 1971. On the possible use of global
  atmospheric models for  the study  of  air and  thermal
  pollution. In Man's Impact  on the Climate. Cambridge
  MIT Press p. 265-276.
Yamamoto, G. & Tanaka, M., 1972. Increase of global al-
  bedo due to air pollution. I. Atm.  Sci., v. 29, No. 8, p.

    Concluding Remarks for the  U.S.-U.S.S.R. Symposium  on
              Comprehensive  Analysis of  the Environment
                                      Leland D. Attaway *
  Comprehensive Analysis of the Environment in-
volves five major problem areas:
  •  Pollutant Characterization:  the identification of
     problem pollutants and the description of their
     sources,  emission characteristics, and  transfor-
     mation processes.
  •  Route and Fate: description of the relationship
     between  pollution  emissions  and ambient  en-
     vironmental quality (including intermediate and
     ultimate  biological locations).
  •  Effects: the relationship between pollution con-
     centrations at the receptor  (victim) and its ef-
     fect upon that receptor,  both health  and  eco-
     logical.  Indirect effects upon economic and so-
     cial systems  must  be considered.
  •  Monitoring  and Pollution Reduction Methods:
     instrumentation for  assessing  emissions  and
     ambient  quality, and technological  and opera-
     tional means for reducing emissions.
  •  Policy:  the  setting of emission or ambient pol-
     lutant standards,  land use prescriptions,  etc.,
     that is,  the  goals of  comprehensive environ-
     mental analysis.
  These problems run the range  of detail from micro
(e.g., human cell processes)  through macro (e.g.,
land use allocations in  a large region).  We  are es-
sentially at the beginning of developing knowledge,
tools and data in  all of  them. Therefore,  one conclu-
sion we can safely draw  is: we  need advances,.and
international  cooperation, at  all levels in all these
problem categories.
  Dr. Izrael  has introduced in  his paper  on Com-
plex Analysis of  the Environment a  comprehensive
mathematical statement of  the  environmental anal-
ysis  problem; a mathematical formula which encom-
passes all the above components, at  all levels of ag-
gregation from micro to macro.  It has two important
potential uses:
   (1) Organizational:  to identify all essential com-
ponents of the problem;  to indicate  their interrela-
tionships, so that research products  on individual
components are  designed to fit  one another overall;
to determine the research priorities, by identifying
the strongest and  weakest  links in the knowledge
chain;  and to coordinate the overall research  pro-
   (2)  Analytic: to actually perform special analy-
ses. However, in its present form the mathematical
statement  is more representative than analytical; the
form taken  for applications will depend upon the
specific objectives and the state of knowledge at the
   We  must  use some such  statement for both  pur-
poses—but  we must  be making  applications  im-
mediately, and so  cannot wait until our knowledge
permits us to use such a comprehensive expression.
Indeed, it is clear that the equation as it stands will
never be used in its analytic role—it  simultaneously
has too much scope and too much detail. One or the
other has to be  reduced, depending  upon the spe-
cific application.
   The regional analysis  of Lake Baykal, discussed
in the  paper System Analysis and Imitation Mathe-
matical Modelling, by Dr.  Izrael et  al.,  represents
what can be done  today in  Comprehensive Environ-
mental Analysis for  a  region: a  group of sector
models (for example: air and water transport; land
use; pollution reduction methods) which can be ap-
plied independently of one  another, but which feed
one another inputs. They include all the components
I  listed earlier: pollutant characterization; pollutant
route and fate; effects; monitoring  and pollution re-
duction methods;  and policy, such as standard set-
ting and land use  allocations.
   The product of  applying these tools for a specific
region must be a comprehensive plan for that region
covering the next  ten or fifteen years. The environ-
ment is but one aspect of  that plan. It should also
include guidance on:
   (1) Environmental goals  (expressed as ambient
air quality standards, water  standards, land-use guide-
lines,  etc.).
   (2) Effluent standards,  such as flue gas scrubber
control guidelines.
   (3) Economic  growth goals.
   (4) Land use.
  •Deputy Assistant Administrator for Program Integration, U.S. Environmental Protection Agency

   (5)  Transportation.
   (6)  Utilities (water supply, power, waste collec-
tion  and treatment).
   (7)  Population growth  and distribution.
All these other  (than environmental) aspects" must
be such as to meet the environmental goals over the
ten to fifteen year period. However, if the cost-ben-
efit balance point so indicates,  then the  environ-
mental goals may have to be relaxed; or the popula-
tion goals; or the economic goals. This plan must be
flexible  enough to change  annually, and it must be
a pragmatic blend of proceeding "today"  with the
tools and knowledge available. It will be a blend of
Best Practical Technology application and ambient
   It is not feasible to set  pollutant standards inde-
pendently  of cost-benefit considerations. All pollu-
tion  cannot be terminated, so clearly some pollution
is  worth the attendant social costs. The  lowest level
of visible organism response  will  often be too costly
a level for a standard, given  the undamaging nature
of the effect. The standards  sometimes must be set
at more relaxed levels closer to, but still safely below,
harmful effect levels—at  least as an interim measure.
We  thus  must consider  "standards" which change
over calendar time,  in  order to move closer  and
closer to our ultimate goals but at a pace which will
not unacceptably damage the economy. But we must
converge to those ultimate  goals.
  Within the context of my earlier (just above)  re-
marks, we would suggest the following candidates as
high priority joint projects. In all cases, maximum
use should  be  made of the product from  Working
Groups already  established  within  the rest of  the
Environmental  Agreement. Indeed, the principal role
of this Comprehensive Environmental Analysis Proj-
ect should be stimulation of integrated working group
efforts. The candidates  are:
   (1)  Pathways, fates and effects of multi-media
pollutants, and related  multi-media standards.
   (2)  Requirements for multiple standards regulat-
ing long and short term doses.
   (3)  Responses of aquatic and terrestrial ecosys-
tems to pollutants.
   (4)  Analysis techniques and measurement meth-
ods for biological and genetic effects.
   (5)  Techniques  for evaluating  socio-economic
costs and benefits.
   (6)  Evaluation of worth and feasibility of a joint
system for assessing pollution concentrations in  the
                                                                     •ft U.S. OOVEINMENT MINTING OFFICE i 1976 O—587-798