v>EPA
United States
Environmental Protection
Agency
Office of Policy Analysis
Office of Policy, Planning
and Evaluation
' . ~> C* ~7
' «Z - 5 /•
February, 1987
Unfinished Business:
A Comparative Assessment
of Environmental Problems
Overview Report
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U.S. ENVIRONMENTAL PROTECTION AGENCY
-j
VI
UNFINISHED BUSINESS:
A COMPARATIVE ASSESSMENT OF ENVIRONMENTAL PROBLEMS
VOLUME I
OVERVIEW
February, 1987
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TABLE OF CONTENTS
Page
Preface, by Lee M. Thomas i
Transmittal Memo iii
Acknowledgments iv
Executive Summary xiii
I. Introduction 1
II. How the Analysis Was Structured 5
A. General Analytical Approach 5
B. How.the Project Was Organized: 17
The Four Work Groups
C. Specific Approaches of the Work Groups ' 21
and Results
1. Cancer Risk . 21
2. Non-Cancer Health Risk 35
3. Ecological Risk 43
4. Welfare Effects 50
III. Summary of What We Learned About the 31 56
Environmental Problems
IV. Public Perceptions of the Environmental Problems 91
V. General Observations and Recommendations 94
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PREFACE
BY
LEE M. THOMAS
ADMINISTRATOR
U.S. ENVIRONMENTAL PROTECTION AGENCY
The mission of the Environmental Protection Agency is bjroad.
The challenges we face are complex and varied. Operating under nine
basic statutes and portions of several others, we have in place
major programs to protect every environmental medium.
Over the past 16 years, we have seen significant improvements
in the quality of our air, water, and land resources. Still,
much remains to be done.
Although EPA's mission enjoys broad public support, our
agency nonetheless must operate on finite resources. Therefore,
we must choose our priorities carefully so that we apply those
resources as effectively as possible.
While we have made much progress to date, the cost of
further environmental improvements in many areas will be high.
For example, removing additional increments of toxics from
industrial effluents or cleaning up contaminated ground water to
background levels can be enormously expensive. The unit cost of
moving ever closer to the point of zero discharge, zero contamination,
and zero risk increases exponentially.
Yet this agency must proceed to carry out its mandates and
to set its priorities. With this in mind, last spring I asked a
task force of EPA career staff members to examine relative risks
to human health and the environment posed by various environmental
problems. I am grateful to the 75 agency professionals who helped
in this effort.
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These employees assembled available data and applied their
best professional judgment on this complex and controversial
subject. Their report — although subjective and "based on
imperfect data — represents a credible first step toward a
promising method of analyzing, developing, and implementing
environmental policy. That is why I am presenting it to the
public as I have received it.
In a world of limited resources, it may be wise to give
priority attention to those pollutants and problems that pose
the greatest risks to our society. That is the measure this
study begins to apply. It represents, in my view, the first
few sketchy lines of what might become the future picture of
environmental protection in America.
This study is not the definitive work on the .subject of
risk-based programs, but we hope it will initiate an important
discussion of the concept. In time, with better data and more
discusssion, I believe the merit in this idea may prove to be
an invaluable tool.
In sharing this report I hope that it will stimulate an
informed discussion. We plan no immediate changes in priorities
until this discussion takes place. We welcome your reactions.
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TRANSMITTAL MEMO
MEMORANDUM TO LEE M. THOMAS, ADMINISTRATOR
Nine months ago you asked us to look at the various
environmental problems that EPA is mandated to address and
report back to you on the relative risks of each of them.
Since that time we and over seventy other career managers and
experts have been working to prepare the report that we hereby
transmit to you.
Preparing this report has been a challenge. Many times we
found that the data we would like to have had simply do not
exist. For that reason this report can best be described as
being based on "informed judgment." But collectively we have a
feeling of reasonable confidence in what we are giving you.
Just as this project made us stretch to deal with the lack
of good data, it also stretched us to think about the full
range of environmental problems that EPA faces. We believe
that our product is useful for purposes of general priority-
setting. We hope that you and others will also find it so.
*
Richard D. Morgenstern, Director
Office of. Policy Analysis
Don R. Clay, Deputy Assistant Administrator
for Air and Radiation
Gerald A. Emison, Director
Office of Air Quality Planning and Standards
Rebecca W. Hanmer, Deputy Assistant
Administrator for Water
Marcia E. Williams, Director
Office of Solid Waste
111
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ACKNOWLEDGEMENTS
Project Leaders
Richard D. Morgenstern - Director, Office of Policy Analysis
(overall project direction and coordination)
Don R. Clay - Deputy Assistant Administrator for Air and Radiation
(Chairperson, Cancer Work Group)
Marcia E. Williams - Director, Office of Solid Waste
(Chairperson, Non-cancer Work group)
Rebecca W. Hanmer - Deputy Assistant Administrator for Water
(Chairperson, Ecological Work Group)
Gerald A. Emison - Director, Office of Air Quality Planning and
Standards (Chairperson, Welfare Work Group)
Work Group- Members and Project Staff
(see following pages)
Key to Abbeviations Used on Following Pages
OAR Office of Air and Radiation
OEA Office of External Affairs
OPPE Office of Policy, Planning and Evaluation
OPTS Office of Pesticides and Toxic Substances
ORD Office of Research and Development
OSWER Office of Solid Waste and Emergency Response
OW Office of Water
IV
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Cancer Risk Work Group
Don Clay
(chairperson)
Anne Barton
Jim Berry
Carey Carpenter
Reto Engler
Bill Farland
Robert Fegley
Jack Fowle.
Frank Gostomski
Fred Hauchman
Francine Jacoff
Jeff Kolb
Deputy Assistant Administrator for OAR
Air and Radiation
Deputy Director, Hazard Evaluation OPTS
Division, Office of
Pesticide Programs
Special Assistant to the Deputy OAR
Assistant Administrator for
Air and Radiation
Environmental Protection Specialist, OW
Office of Ground Water
Protection
Chief, Scientific Mission Support, OPTS
Section, Toxicology Branch,
Office of Pesticide
Director, Carcinogen Assessment ORD
Group, Office of Health
Environmental Assessment
Regulatoy Impact Analyst, Office of OPPE
Policy Analysis
Acting Director, Water and Toxic ORD
Substances Health Research
Division, Office of Health
Research
Chief, Water Ouality Criteria Section, OW
Office'of Water Regulations
and Standards
Environmental Health Specialist, OAR
Pollutant Assessment Branch,
Office of Air Quality
Planning and Standards
Former Section Chief, Waste OSWER
Characterization Branch,
Office of Solid Waste
Economist, Analysis and Evaluation OSWER
Staff, Office of the
Assistant Administrator
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Arnold Kuzmack
A. W; Marks
Carl Mazza
Dave Patrick
Peter Preuss
Tom Purcell
Jerry Puskin
John Quest
James Repace
Art Spratlin
Donn Viviani
Jeanette Wilste
Craig Zamuda
Director, Program Development and OW
Evaluation Division
Office of Drinking Water
Chief, Economic, Policy Analysis, OW
and Data Management Branch,
Office of Drinking Water
Science Advisor, Office of Toxic OPTS
Substances
Former Chief, Pollutant Assessment OAR
Branch, Office of Air Quality
Planning and Standards
Director, Office of Health and ORD
Environmental Assessment
Environmental Scientist, Criteria OW
and Standards Division,
Office of Water
Regulations and Standards
Chief, Bio-Effects Analysis Branch, OAR
Office of Radiation Programs
Team Leader, Scientific Mission OPTS
Support Section, Toxicology
Branch, Office of
Pesticide Programs
Chief, Technical Services for Indoor
Air Program, Office of Air
and Radiation
Director, Air and Toxics Division
Chief, Regulatory Analysis Branch,
Office of Standards and
Regulations
Air Toxics Coordinator, Office of the
Assistant.Administrator
Environmental Protection Specialist,
Office of Emergency and
Remedial Response
OAR
Reg . 7
(Kansas
City)
OPPE
OAR
OSWER
VI
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Non - Cancer Health Effects Work Group
Marcia Williams
(chairperson)
Don Barnes
Anne Barton
Gary Burin
Ila Cote
joe Cotruvo
Alex Cristofaro
Kim Devonald
David Fege
Susan Goldhaber
Michael Gruber
Director, Office of Solid Waste OSWER
Science Advisor, Office of the OPTS
Assistant Administrator
Deputy Director, Hazard Evaluation OPTS
Division, Office of
Pesticide Programs
Toxicologist, Science Integration OPTS
Staff, Hazard Evaluation
Division, Office of
Pesticide Programs
Toxicologist, Office of Air Quality OAR
Planning and Standards
Director, Criteria & Standards OW
Division, Office of Drinking
Water
Chief, Air Economics Branch, Office OPPE
of Policy Analysis
Oceanographer, Office of Marine and OW
Estuarine Protection
Section Chief, Policy Analysis Section, OSWER
Office of Solid Waste
Toxicologist, Office of Drinking OW
Water
Director, Office of Policy, Planning OSWER
and information, Office of
Solid Waste
Stephanie Irene
Bruce Jordan
Stacey Katz
Section Chief, General Toxicology OPTS
Section, Oncology Branch,
Office of Toxic Substances
Chief, Ambient Standards Branch, OAR
Office of Air Quality
Planning and Standards
Regulatory Impact Analyst, Office of OPPE
Policy Analysis
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Carl Mazza
Hugh McKinnon
Paul Milvy
Bruce Mintz
Dorothy Patton
Harvey Richmond
Dale Ruhter
Science Advisor, Office of Toxic OPTS
Substances
Acting Director, Office of Health ORD
Research
Senior Analyst/Expert, Office of OSWER
Assistant Administrator
Biologist, Office of Drinking OW
Water
Executive Director, Risk ORD
Assessment Forum
Environmental Specialist, Ambient OAR
Standards Branch, Office of
Air Quality Planning
and Standards
Chief, Economic Analysis Staff, OSWER
Office of Solid Waste
Randy Smith
Larry Zaragosa
Chief, Hazardous Waste Policy
Branch
Environmental Scientist, Office of
Assistant Administrator
Reg. 10
(Seattle)
OSWER
V11.1
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Ecological Effects Work Group
Rebecca Hanmer
(Chairperson)
Dennis Athayde
Robert Bastian
jay Benforado
Peter Caulkins
Wendy Blake-Coleman
Dave Davis
Robert Davis
Charles Delos
Jim Gilford
Charles Gregg
Norbert Jaworski
Deborah Martin
Brian McLean
Jim Plafkin
Deputy Assistant Administrator
Chief, Non-Point Source Control,
Office of Marine and
Estuarine Protection
Environmental Engineer, Office of
Municipal Pollution
Control
Ecologist
Environmental Economist, Economic
Studies Branch, Office
of Policy Analysis
Environmental Protection Specialist
Office of Ground Water
Protection
Deputy Director, Office of Federal
Activities'
Environmental Scientist
Environmental Scientist, Office of
Regulatory and Standards
Chief, Environmental Effects Branch
Office Toxic Substances
Special Assistant, Office of the
Assistant Administrator
Director, Environmental Research
Lab, Narragansett
Program Analyst, Program Operations
Staff, Office of Solid
Waste
Chief, Implementation Issues Staff
Office of Program
Development
Biologist, Office of Water
Regulation and Standards
OW
OW
OW
ORD
OPPE
OW
OEA
Region 3
(Philadelphia)
OW
OPTS
OW
ORD
OSW
OAR
OW
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Mike Slimak Chief, Ecological Effects Branch OPTS
Office of Pesticide
Programs
Jim Weigold Policy Analyst, Office of Air OAR
Quality planning and
Standards
Robert Wolcott Director, Economic Regulatory OPPE
and Analysis Division,
Office of Policy Analysis
Robert Zeller Policy Advisor, Office of Marine and OW
Estuarine Protection
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Welfare Effects Work Group Members
Gerald A. Emison
(Chairperson)
Allen _C. Basala
John Calcagni
Gary J. Foley •
Jeffrey A. Kolb
Peter J. Kuch
Robert E. Lee II
Ralph A. Luken
Mark A. Luttner
John L. Malanchuk
William B. O'Neil
Michael G. Shelby
Director, Office of Air Quality OAR
Planning and Standards
Chief, Regulatory Impact Analysis OAR
Section, Office of Air
Quality Planning and
Standards
Chief, Economic Analysis Branch, OAR
Office of Air Quality
planning and Standards
Director, Acid Deposition and Atoms- ORD
pheric Research Division
Economist, Analysis and Evaluation OSWER
Staff
Leader, Industrial and Natural OPTS
Resource Economics Section,
Office of Pesticide Programs
Chief, Regulatory Impacts Branch, OPTS
Office of Toxic Substances
Chief, Economic Studies Branch,
Office of Policy Analysis OPPE
Chief, Economic Analysis Branch, OW
Office of Water Regulations
and Standards
Team Leader, Acid Deposition and ORD
Atmospheric Research
Division
Economist, Economic Studies Branch, OPPE
Office of Policy Analysis
Economist, Air Economics Branch, OPPE
Office of Policy Analysis
XI
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Project Staff
Frederick W. Allen - Assoc. Director, Office of Policy Analysis
(OPA), OPPE
Robert W. Fegley - Senior Analyst, OPA, OPPE (Cancer Work Group)
Stacey A. Katz - Regulatory Impact Analyst, OPA, OPPE (Non-cancer
Work Group)
Peter P. Caulkins - Environmental Economist, OPA, OPPE (Ecological
Work Group)
Michael G. Shelby - Economist, OPA, OPPE (Welfare Work Group)
Deloris A. Swann - Secretary, OPA, OPPE
Special thanks also due to Stuart L. Sessions (consultant) and
Joan O'Callaghan (editor).
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EXECUTIVE SUMMARY
When the Environmental Protection Agency (EPA) was established
in 1970, the nation's most pressing environmental problems were
obvious. Important polluters and pollutants were the visible
ones: soot and smoke from cars and smokestacks, and the raw
sewage and chemicals from municipal and industrial wastewater.
Since 1970 the nation has done much to abate the most visible
forms of pollution, but there is still much unfinished business.
Moreover, new problems have also been "discovered" or have
risen in importance, such as indoor radon, global climatic
change from the buildup of carbon dioxide in the atmosphere,
acid precipitation and hazardous waste. Many of these new
problems are difficult to evaluate, as they involve slow,
cumulative changes with very serious possible ultimate effects,
amidst considerable scientific uncertainty. Many involve toxic
chemicals that can cause cancer or birth defects at levels of
exposure that are hard to detect. And many involve persistent
contaminants that can move from one environmental medium to
another, causing further damage even after controls have been
applied for one medium.
The complexity and gravity of these issues make it particularly
important that EPA apply its finite resources where they will
have the greatest effect. Thus, the Administrator of EPA
commissioned a special task force of senior career managers and
technical experts to assist him and other policy makers in this
task. The assignment was to compare the risks currently associated
with major environmental problems, given existing levels of
control. However, there was no thought that risks alone ought
to determine agency priorities. Thus, the results of this
project cannot be used by themselves to set priorities.
Methodology
In conducting the project, we organized and limited our
work in four important ways. First, we divided the universe of
environmental problems into 31 pieces. Each of the pieces
represents an environmental problem area defined along lines
corresponding generally with existing programs or statutes.
For example, some of our 31 problem areas are: criteria air
pollutants, hazardous air pollutants, contaminants in drinking
water, abandoned hazardous waste {e.g., Superfund) sites,
pesticide residues on food, and worker exposures to toxic
chemicals.
Second, we considered four different types of risk for
each problem area: cancer risks, non-cancer health risks,
ecological effects, and welfare effects (visibility impairment,
materials damage, etc.). Each type of risk was analyzed separately.
There were no decisions that one type was more important than
another, and we made no attempt to "add" risks for a problem
area across the four risk types.
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Third, in view of the already massive scope of the project,
we decided to limit it by not considering:
o the economic or technical controllability of the risks;
o the qualitative aspects of the risks that people find
important, such as the degree to which the risks are
voluntary, familiar, or equitable;
o the benefits to society of the activities that cause
the environmental problems; and
o the statutory and public mandate (or lack thereof) for
EPA to deal with the risks. Some problems among the
31 are primarily within the purview of other agencies.
Finally, because the intent of the project was to identify
areas of unfinished business, we assessed risks as they exist
now — given the levels of control that are currently in place.
We did not aim to assess risks that have been abated.
The method we used to compare environmental problem areas
can best be described as systematically generating informed
judgments among Agency experts. About 75 career managers and
experts representing all EPA programs participated over a
period of about nine months. The participants assembled and
analyzed masses of existing data on pollutants, exposures, and
effects, but ultimately had to fill substantial gaps in available
data by using their collective judgment. In this sense, the
project represents expert opinion rather than objective and
quantitative analysis. But despite the difficulties caused by
lack of data and lack of accepted risk assessment methods in
some areas, the participants feel relatively confident in their
final relative rankings.
Results
The major results from the project are rankings of the 31
problem areas for each of four types of risk. The .rankings are
based on risks existing today, assuming that current controls
stay in place. We found the following:
o No problems rank relatively high in all four types of
risk, or relatively low in all four. Whether an
environmental problem appears large or not depends
critically on the type of adverse effect with which
one is concerned.
o Problems that rank relatively high in three of four
risk types, or at least medium in all four include:
criteria air pollutants; stratospheric ozone depletion;
pesticide residues on food; and other pesticide risks
(runoff and air deposition of pesticides).
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o Problems that rank relatively high in cancer and non-
cancer health risks but low in ecological and welfare
risks include: hazardous air pollutants; indoor
radon; indoor air pollution other than radon; pesticide
application; exposure to consumer products; and
worker exposures to chemicals.
o Problems that rank relatively high in ecological and
welfare risks, but low in both health risks include:
global warming; point and non-point sources of surface
water pollution; and physical alteration of aquatic
habitats (including estuaries and wetlands) and
mining waste.
o Areas related to ground water consistently rank medium
or low.
In some respects, these rankings by risk do not correspond
closely with EPA's statutory authorities. For example, in two
relatively high health risk areas EPA shares jurisdiction with
other agencies that have more direct responsibility: consumer
products (the Consumer Product Safety Commission) and worker
exposures to toxic chemicals (the Occupational Safety and
Health Administration).
The rankings by risk also do not correspond well with
EPA's current program priorities. Areas of relatively high
risk but low EPA effort include: indoor radon; indoor air
pollution; stratospheric ozone depletion; global warming;
non-point sources; discharges to estuaries, coastal waters, and
oceans; other pesticide risks; accidental releases of toxics;
consumer products; and worker exposures. Areas of high EPA
effort but relatively medium or low risks include: RCRA sites;
Superfund; underground -storage tanks; and municipal non-hazardous
waste sites.
This divergence between what we found in terms of relative
risks and EPA's priorities is not necessarily inappropriate.
Some problems appear to pose relatively low risks precisely
because of high levels of program effort that have been devoted
to controlling them. And these high levels of attention may
remain necessary in order to hold risks to current levels.
Overall, EPA's priorities appear more closely aligned with
public opinion than with our estimated risks. Recent national
polling data rank areas of public concern about environmental
issues as follows:
o High: chemical waste disposal, water pollution, chemical
plant accidents, and air pollution;
o Medium: oil spills, worker exposure, pesticides, and
drinking water;
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o Low: indoor air pollution, consume* products, genetic
radiation (except nuclear power), and global warming.
A final item resulting from the project is the agenda it
has given EPA for improving data and methods for performing
environmental risk assessments. We have found it impossible to
perform this project in a quantitatively rigorous fashion. The
best information we have is on the environmental causes of
cancer, but it is weak even here. There is a general lack of
information on and attention to welfare and ecological effects.
Exposure data are often poor in all four areas, even in problem
areas where major regulatory efforts are under way. No generally
accepted methods exist for assessing ecological or non-cancer
health effects.
Despite the numerous difficulties involved in performing
this project, the participants are confident in its general
results and are enthusiastic about organizing environmental
protection more around the goal of reducing risks. This study
should stimulate discussion among policy makers and the public
as to what EPA's priorities should be. A collective resolve
that the debates about environmental policy should include more
information of the type in this report would be a very significant
outcome of this project.
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CHAPTER I
INTRODUCTION
The fundamental mission of the Environmental Protection
Agency (EPA) is to reduce risks - to health, ecosystems and
welfare. When the EPA was established in 1970, Congress set
specific priorities based on the most visible polluters and
pollutants: soot and smoke from motor vehicles and smokestacks,
and raw sewage .and chemicals from municipal and industrial waste-
water.
Substantial progress has been made in controlling these more
visible problems, but much unfinished business remains. Now "newer1
issues, such as hazardous waste, toxic air emissions, indoor
radon, global climatic change and acid rain, beg for attention
alongside the old ones. It is not immediately clear which
problems pose the greatest risks and which should be given the
greatest priority by an agency that now administers nine major
statutes and has programs that address dozens of environmental
problems.
This is why the EPA Administrator commissioned a task force
of senior career officials and technical experts staff to carry
out what became known as the "Comparative Risk Project." The
objective was to develop a ranking of the relative risks associated
with major environmental problems that could be used as one of
several important bases on which EPA could set priorities. Until
this project was launched, there was no systematic comparison of
the different risks the Agency is addressing or could address.
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From the outset the project team recognized that it is
impossible to directly compare the risks of different environ-
mental problems. While great amounts of information do exist,
the inconsistencies in the ways the data have been prepared, the
data gaps and uncertainties, and the lack of an adequate risk
assessment methodology in some areas prevent a scientifically
precise analysis. Great differences in types of damages also
hamper comparisons. In the face of these problems, the project
team was often required to make professional judgments on the
basis of available data. Because of these uncertainties the
results of this project should be regarded as not analytically
pure but rather as judgmentally correct and unlikely to be far
wrong.
The project team was willing to make th^se judgments and
stand behind them because for the purposes of priority setting ^
absolute precision is not mandatory. Sufficient precision to
allow a general comparative ranking is all that is needed.
Indeed, by its very nature, the process of setting agency priorities
is multifaceted and imprecise. This report provides insight into
only one factor, risk, of the many which must be considered in
setting priorities. Other factors are also critical. Except as
noted, these factors were not studied in this project:
0 the benefits to society of the activities that cause the
environmental problems;
0 the technical feasibility, likely effectiveness, and
projected cost of available control options;
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0 the nature and extent of current legislative authority
and the mandate of political and public opinion to act
on each identified problem (partly covered in this report);
0 EPA's own ability to make a difference, as well as the
extent to which effective action could be or is already
being taken by others to address the problem; and
0 the intangible aspects of the risks that people find
important—the degree to which the risks are voluntary,
controllable by the individual, familiar, generally
accepted, equitable, etc., and the extent to which people
value a resource for its own sake or for future generations.
Within this context, the results of this project are intended
to serve as a guide to broad, long-term priority setting. Depending
on how a problem appears against the criteria cited above, EPA's
response to a risk might involve one or more of the following
activities:
0 conducting research to understand the problem and/or develop
methods of control;
0 disseminating information and educating the public;
0 initiating or increasing program activity, such as issuing
regulations, writing permits, or enforcing regulations
and permits;
0 asking or helping others (e.g., Congress, state and local
governments, individual citizens) to legislate or take
appropriate action; or even
0 taking no action, where the risk is low.
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For these reasons, setting priorities will always require
managerial judgment. It will also be a subject of public debate.
This report is intended to assist in those processes.
This overview report discusses the general analytical approach
followed in the project and the specific methods used to assess
cancer, non-cancer health, ecological and welfare risks (Chapter 2);
the results of the comparative ranking of environmental problems
(Chapter 3); public perception of the environmental problems
(Chapter 4); and overall observations and recommendations (Chapter
5). Four appendices include the detailed reports from individual
work groups on cancer, non-cancer health, ecological and welfare
risks.
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CHAPTER II
HOW THE ANALYSIS WAS STRUCTURED
A. General Analytical Approach
When planning began for this project in early 1986, the task
force made several important decisions about the general analytical
approach to be used. They decided (1) to consider four major
types of health and environmental risks, (2) to define a specific
set of environmental problems for which these risks would be
assessed, (3) to focus on risks that exist today, (4) to use both
quantitative data and expert judgment, and (5) to set common
analytical guidelines for analyzing the different risks.
(1) Consider 'four major types of risk; cancer risks, non-cancer
•health risks, ecological effects and-welfare effects
Many studies of risk .associated with EPA programs have
tended to focus only on health risks, and more specifically on
cancer risks. Obviously, EPA's role is much bigger than that.
EPA is also legislatively responsible for protecting natural
ecosystems and the general public welfare as well as public
health. Thus, the task force decided to look at four major types
of risks that environmental problems present. Each type of risk
was analyzed separately; no decision was made that one type is
more important than another and no attempt was made to "add"
across risk types.
0 Cancer risks, as examined in this study, are self-explanatory.
Numerous chemicals are either proven or suspected to be
human carcinogens, and people may come into contact with
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these chemicals through environmental exposures. In
certain instances, where data exist, both cancer cases and
cancer deaths from environmental issues were studied.
Non-cancer health risks span a very large range. Toxic sub-
stances in the environment can cause numerous adverse health
effects in addition to cancer. The project looked at eleven
types of effects: cardiovascular, developmental, hematopoietic,
immunological, kidney, liver, mutagenic, neurotoxic/behavioral,
reproductive, respiratory, and "other." These adverse
health effects can range from acute (e.g., immediate pesticide
poisoning) to chronic (e.g., kidney disfunction from prolonged
exposure to cadmium).
Ecological effects on natural ecosystems result from both
habitat^modification and environmental'pollution. Pollutants
of cpncern can range from toxics (e.g., mercury and pesticides)
to conventional pollutants (e.g., salt and sediment). They
are produced by such diverse sources as runoff, effluents
and air deposition. The ecosystems that they can affect
include salt water, fresh water, terrestrial and avian
systems, both plant and animal.
Welfare effects include a variety of damages to property,
goods and services or activities to which a monetary value
can often be assigned. These include natural resources
(e.g., crops, forests and fisheries), recreation (e.g.,
tourism, boating), materials damage and soiling (e.g., building
materials), aesthetic values (e.g., visibility) and various
public and commercial activities.
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While this four-part typology of risk reflects many of the
tangible characteristics of environmental risks, it does not
reflect most of the intangible characteristics that people often
find just as important. These include such qualitative aspects
as the degree to which the risks are voluntary, controllable by
the individual, familiar or generally accepted. Another important
aspect of environmental problems is equity. Frequently environ-
mental problems affect some people or ecosystems more than others
and the most efficient way of dealing with them (the greatest
good for the greatest number at the least total cost) is judged
unfair to some.
A related aspect that we did not fully consider because of
data limitations is the risks environmental problems pose to .
what are often called "options values" and "existence values."
The benefits of something that has a use value are realized when
that thing is used. In contrast, intrinsic, "nonuser" benefits
are derived from something with option and existence values. An
option value is based on the benefit of preserving the option to
use a resource in the future. Existence value is based on the
knowledge that a resource merely exists or that it exists in a
pristine form.
In many instances, people value environmental quality to a
greater degree than the tangible benefits they derive from a
clean environment would seem to suggest. This is because of the
intangible characteristics of the risks. People place intrinsic
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value on a c:^^n environment. The public's vehement insistence
on cleaning up contaminated ground-water aauifers even when they
are not currently being used is an example of these important
intangible values.
The fact that we did not fully consider these intangible
characteristics in this project should in no way suggest that
they are unimportant. In fact, a number of studies have found
that they are a significant component of what the public perceives
as the total value derived from environmental protection. Rather,
we did not fully consider them here merely because not enough
work has been done in this area to enable the project participants
to assess them fairly for all the environmental problems examined
in the projects
(2) Define a specific set of environmental problems for the
analysis
The second key decision concerned how the universe of environ-
mental problems was divided up to be analyzed. There are many
ways to slice the pie. The most consistent ways to define environ-
mental problems are by sources (e.g., power plants or refineries),
by pollutants (e.g., sulfur dioxide or benzene), by pathways
(e.g., air or water) or by receptors (e.g., people or forests).
But we chose another approach. We defined the problems on the
general basis of how the laws are written and environmental
programs are organized. Since the goal of the project was to put
together a useful tool to compare the risks with which EPA is
concerned, the project team decided to draw up a list of environ-
-------
mental problems that reflect how people think of the problems,
even though it turns out that people do not think of them in an
entirely consistent manner.
The list of problems that the group chose to examine is
shown in Table 2-1. Some of these problems are diffuse mixtures
of sources, effects and a variety of different problems. This
has led to some "double counting" of risks in more than one
problem area. For example, health risks from inactive hazardous
waste sites (problem area #17) often result when people either
drink contaminated water or inhale volatile toxic chemicals.
Such health risks will be double counted by the drinking water
problem area (#15) or by the hazardous air pollutant problem area
(#2). We made these definitional decisions because we thought it
important to define the environmental problems as they are commonly
perceived — that is, from a variety of overlapping points of
view. The major instances of double counting are noted in the
body of the report. Further definitions of the problems are
given in Chapter III of this Overview Report.
There is no special reason why the group chose to examine
exactly 31 problems (in theory it could have been 11 or 111).
The project team simply decided that a number between two and
three dozen represented an appropriate balance between the guest
for detail and the necessity of keeping the analysis manageable.
In this context, it is also important to note that how the universe
of environmental problems was divided up had an important effect
on the relative ranking of the problems. The broader the category,
the more impacts it covers, and vice-versa.
-------
Table 2-1
List of Environmental Problems Studied in This Project
(Not in Rank Order)
Reference
Number Environmental Problem
1. Criteria air pollutants from mobile and stationary
sources (includes acid precipitation)
2. Hazardous/toxic air pollutants
3. Other air pollutants (includes fluorides, total reduced
sulfur, substances not included above that emit odors)
4. Radon - indoor air only
5. Indoor air pollutants - other than radon
6. Radiation - other than radon
7. Substances suspected of depleting the stratospheric ozone
layer - CFC's, etc.
8. CC>2 and global warming
9. Direct, point source discharges (industrial, etc.) to
surface water
10. Indirect, point source discharges (POTW's) to surface
water
11. Nonpoint source discharges to surface water
12. Contaminated sludge (includes municipal and scrubber
sludge)
13. To estuaries, coastal waters and oceans from all sources
14.. To wetlands from all sources
15. From drinking water as it arrives at the tap (includes
chemicals, lead from pipes, biological contaminants,
radiation, etc.)
16. Hazardous waste sites - active (includes hazardous waste
tanks) (groundwater and other media)
17. Hazardous waste sites - inactive (Superfund) (groundwater
and other media)
18. Non-hazardous waste sites - municipal (groundwater and
other media)
19. Non-hazardous waste sites - industrial (includes utilities)
(groundwater and other media)
20. Mining waste (includes oil and gas extraction wastes)
21. Accidental releases - toxics (includes all media)
22. Accidental releases - oil spills
23. Releases from storage tanks (includes product and petroleum
tanks - above, on and underground)
24. Other groundwater contamination (includes septic systems,
road salt, injection wells, etc.)
10
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Table 2-1 (continued)
25. Pesticide residues on foods eaten by humans and wildlife
26. Application of pesticides (risks to applicators, which
includes workers who mix and load, as well as apply,
and also consumers who apply pesticides)
27. Other pesticides risks, including leaching and runoff of
pesticides and agricultural chemicals, air deposition
from spraying, etc.
28. New toxic chemicals
29. Biotechnology (environmental releases of genetically
altered materials)
30. Consumer product exposure
31. Worker exposure to chemicals
11
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Another point to note is that when we were able to, we tried
to take account of intermedia transfers and secondary effects.
Some pollutants easily cross the boundaries of environmental
media (e.g., air, water). Sulfur dioxide (SO2) emissions are a
good example. Our estimate of risk from criteria air pollutants,
including S02/ covers risks from S02 in the air (e.g., health
effects from breathing it), as well as damages from the deposit
of sulfates on structures (e.g., materials damage) and from
their eventual arrival in water (e.g., ecological damages from
acid rain). Essentially, we attempted to follow the pollutant
"from the cradle to the grave." Secondary effects occur when
pollutants such as SC>2 are chemically transformed by natural
processes after being emitted and do damage .in a new form.
While counting intermedia transfers and secondary effects
may have resulted in some double counting of effects (as the same
environmental problems are evaluated in different media) , it
should provide a more comprehensive assessment of comparative
risks. Unfortunately, for some environmental problems data are
simply too scarce to allow for such a comprehensive assessment.
(3) Focus on risks present now
Because the intent of the project was to identify areas of
unfinished business, we focused on risks that are present now,
or that are being generated by present activities. We assumed
the maintenance of the existing environmental programs (i.e.,
their existing stages of development and at existing levels of
resources and compliance). We thus examined residual risks rather
12
-------
than inherent risks (total uncontrolled risks) or risks that have
already been or could be controlled. We did not assume that all
current statutory and regulatory requirements are being complied
with; instead, we tried to judge the actual degree of compliance.
Put differently, we looked at where EPA might be able to have an
impact in the future, not where it already has had an impact.
This assumption is very important. Many environmental problems
show up in this analysis as moderate or low risks precisely
because extensive controls are already in place and are being
maintained, often at considerable expense.
Within these bounds, we decided against putting strict
statutory or regulatory bounds on the analysis. We assessed
environmental risks broadly defined, whether or not EPA or some
other governmental agency had the mandate or the ability to
address them. The advantage to this approach is that it can
point us toward areas we need to develop and seek statutory
authority to address. In addition, it does not prejudge the
policy and legal issues related to EPA's regulatory authority.
Thus, for example, we assessed environmental risks over which
other agencies have lead responsibility (e.g. worker and consumer
exposures). Even in an area where EPA does have clear statutory
authority, such as in assessing the risks of abandoned hazardous
waste sites, we tried to the extent possible to address (1) waste
sites that are currently on the National Priorities List, as well
as (2) sites that states are handling because they did not rank
high enough on the Superfund Hazard Ranking System.
13
-------
Further, as mentioned in Chapter I, we looked only at risks,
and not at the feasibility Off costs of controlling those risks.
Thus, we repeat, the information collected in this report is not
by itself sufficient to support an analysis of agency priorities.
(4) Use both quantitative data and expert judgment
The results of this project can best be described as being
based on "informed judgment." From the outset we recognized
that the data available for this analysis are incomplete and of
highly variable quality. For this reason, making very precise
quantitative comparisons is impossible. In some problem areas,
risk estimates exist only for a portion of the problem; for
example, to our knowledge no one has produced a nationwide estimate
of the risks from abandoned hazardous waste (Superfund) sites.
In some problem areas data exist oh risks from one but not another
route of exposure. In other problem areas, risk data may exist
for some chemicals but not others. Even where data do exist on
risks, they have frequently been generated somewhat differently
and are therefore difficult to compare. Thus, the we frequently
had to extrapolate risks from incomplete analyses and had to
compare estimates of disparate quality.
In doing so, we took several precautions. We collected
quantitative information available within the Agency, interpreted
the types and qualities of data, stated our assumptions, and,
finally, made educated judgments. We also compared our results
with those of other studies. Because our use of qualitative
judgment was extensive, the results of this study are not
14
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scientifically "reproduceable." Nevertheless, we are generally
confident in the overall rankings, given the way the problem
areas were defined. in each case we have stated our confidence
in the data and in our judgments.
(5) Set Common Analytical Guidelines
To ensure consistency in the analyses, we tried whenever
possible to apply similar methods across the four areas when
estimating risks. However, in many cases we were not able to do
this, and had to resort to our collective professional judgment.
In general, our attempts in this respect included using common
assumptions about emissions, exposure and dose/response relation-
ships; measuring effects whenever they occur from current problems;
and presenting the risks in terms of both the risk to the total
population and the maximum risk to an individual, where possible
and appropriate.
a. Using Assumptions About Emissions, Exposure and
Dose/Response Relationships
EPA analyses have made differing assumptions about emissions
of various pollutants, the exposure that people, ecosystems and
objects receive and dose-response relationships. Comparing estimates
generated under incompatible assumptions was difficult. In some
instances where there were sufficient data, we tried to coordinate
assumptions. In other instances, we simply tried to judge the
magnitude of the bias produced by the incompatible assumptions
and compared risks without reworking the underlying quantitative
estimates.
15
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b. Measuring Effects Whenever They Occur From
Current Problems
The time frame during which exposures (and subsequent damages)
occur may bias an analysis either in favor of or against certain
problems. For example;
0 many of the effects associated with various air pollutants
take place at essentially the same time as they are emitted
into the environment;
0 ground water contamination from hazardous waste sites may
not affect human health for years, even decades, after
contaminants have leached from a site.
To facilitiate a fair representation of the damages from all
environmental hazards, we tried to estimate all the damages that
will occur from the problem as it exists now. Instead of discounting
or using some other method of indicating time preference, we
simply presented damages in terms of their magnitude, sometimes with
a notation about the time at which they occur. If, for example,
damages from exposure to various air pollutants begin to accrue
in year 1, while those associated with Superfund sites do not begin
for.30 years, we simply recognize those facts, without any accompanying
judgment on their policy importance.
Just as there may be a time lag between emissions and exposure,
there may also be a time lag between exposure and damages.
Latency, which is the time lag between exposure and final
effect, has been a very controversial issue, particularly for
carcinogens. It is also relevant to mutagenic and certain repro-
16
-------
ductive effects. Latent effects should not be confused with
damages from chronic exposures, which require long periods of
exposure before effects are noted. We have chosen again to
assess damages whenever they will occur from current environmental
problems, and thus do not discount latency periods.
c. Considering Total population and Maximum Individual
Risks
The first priority in this project was to evaluate risks to
the total population. However, the cancer and non-cancer work
groups characterized both the risk to the total population and
the risk to the most exposed individual. For certain environmental
problems only a relatively small number of people may be exposed
(e.g., pesticide applicators); however, the risks those individuals
face may be significant. Therefore, we were interested in descriptions
of both aggregate population and individual risk.
B. How the Project Was Organized - The Four Work Groups
The general analytical approach determined how the project
would be organized. Four work groups — on cancer, non-cancer
health effects, ecological effects and welfare effects — were
established and given the task of ranking the 31 problem areas
according to each type of risk. The work groups were given the
common analytical ground rules discussed in the previous section,
but were otherwise left to develop their own approaches to ranking.
The work groups were selected with great care. Each was
chaired by a senior EPA official who had many years of Agency
17
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experience covering multiple program areas. The work group
chairpeople were:
o Cancer: Don Clay, at first Director of the Office of
Toxic Substances, and now Deputy Assistant Administrator
for Air and Radiation;
o Non-cancer: Marcia Williams, Director of the Office of
Solid Waste;
o Ecological: Rebecca Hanmer, Deputy Assistant Administrator
for Water;
o Welfare: Gerald Emison, Director of the Office of Air
Quality Planning and Standards.
Each work group had at least one representative from each of EPA1s
program offices. The work groups had expertise appropriate to their
subject areas. For the most part, health scientists were on the
cancer and non-cancer groups, biological scientists were on the
ecological group, and the welfare group consisted mostly of
economists. Most of these individuals were either managers or
senior scientists who were chosen because of their extensive
knowledge of data and methods for assessing risks in their
program areas.
Although each work group devised its own approach to
assessing risks and ranking the 31 problem areas, there were
some similarities among the "processes that each eventually
followed. All of the work groups proceeded through three basic
steps:
1. Agreeing on an overall conceptual approach for comparing
risks among the problem areas. For cancer and welfare
effects this task was more straightforward than for
18
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the other two groups. Standard or agency-approved
methods already existed for assessing cancer risks and
for. valuing welfare damages. Common denominators for
comparing cancer risks (numbers of cases) and welfare
effects (dollar losses) also already existed. Developing
the conceptual approaches in the non-cancer and the
ecological areas was much more difficult.
2. Accumulating and organizing existing data on risks fov
each problem area. Each work group prepared "summary
sheets" on the 31 problem areas, typically describing
existing information on risks, sources of data and
major uncertainties. The summary sheets were prepared
by the program office most knowledgeable about each
problem area, an-d they were then circulated to the
entire work group to provide a common base of information
for ranking the problem areas.
3. Combining the data from the summary sheets with the judg-
ment of work group members to produce a relative
ranking of the problem areas. In all four work groups,
gaps and uncertainties in the available quantitative
information made it impossible to produce a purely
objective ranking. The groups typically had data on
only portions of environmental problem areas, e.g., on
some chemicals, some exposures, some health effects,
or some impacts. The four groups each had to face the
issue of how to extrapolate from the portion of the
problem that they could assess to the likely extent of
the entire problem.
19
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The differences in how the work groups approached their
tasks were largely the result of the characteristics of the risk
areas they studied and the available data. For instance, as
outlined in the following section of this chapter, the non-
cancer and ecological groups dealt with many different effects.
The non-cancer group developed a special severity index to help
rank problems. The ecological group created a special panel of
outside experts to help organize their data.
• Throughout this process, the work group chairpersons
sought to create conditions that would make the judgments as
informed, expert and systematic as possible. The work groups
successfully developed a spirit of striving for objectivity in
this project; the participants generally 'have not pursued
parochial interests or sought to make their own programs "look
good." Work group judgments have all been arrived at collectively.
Central direction for the work groups, on matters such as
the project schedule, common definitions of problem areas and
methodological ground rules, was provided from three sources.
First, Richard Morgenstern, Director of the Office of Policy
Analysis (OPA), provided overall coordination for the project.
Second, one OPA analyst was assigned to each work group to serve
as a primary staff member and to provide linkage among the work
groups. Finally, the four work group chairpersons and Dr.
Morgenstern met frequently to compare progress and resolve
crosscutting issues.
20
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The entire project took about nine months. Significant
amounts of managerial and staff time were spent on it. Besides
providing a sense of the comparative risks of various environ-
mental problems and a basis for establishing better environmental
priorities, the project was an especially valuable experience
for the participants, many of whom knew relatively little about
environmental problems beyond those in their own program areas
when they started this project.
The next section of this chapter summarizes the methods used
by each of the four work groups to rank the 31 problem areas and
their results.
C. Specific Approaches of the Workgroups and Results
(1) Cancer Risk
In one sense, the cancer work group faced an easier task in
comparing the risks of the 31 environmental problems than did
the other work groups. A basic method for assessment of
carcinogenic risk has been adopted by the Agency. Furthermore,
the agency has generally followed a policy of aggregating different
forms of cancer with the exception of skin cancers. The result
was that the work group began this project with a base of a
single common currency for comparing disparate environmental
problems, and an approved procedure for estimating this quantity.
The work group initially aimed to assess the cancer incidence
associated with environmental exposures to carcinogens for each
of the 31 problem areas. As was true for some of the other
21
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several environmental problems. Wetlands and estuaries (environ-
mental problems 13 and 14) were eliminated from consideration
as their inclusion would necessitate double counting. It was
assumed that the cancer risk attributed to these environmental
problems, largely through the consumption of contaminated
seafood, would be captured by other problems which investigate
discharges into surface and ground waters.
Because this project drew only on existing quantitative
information, and did not involve research to generate new
information, the group had to do without quantitative information
on several programs that do not generally conduct cancer risk
assessments. In general, it was the consensus of the committee
that these environmental problems posed relatively low cancer
risks, but the reader'should be aware that this assessment may
»
be biased by a lack of quantitative information. Problems that
fell into this category were direct and indirect point source
discharges to surface waters (#9 and #10), and other groundwater
contamination (#24).
There were three environmental problems for which no cancer
risk could be identified. "Other air pollutants" (#3) were not
considered in this analysis, as it was assumed that carcinogenic
air pollutants, by definition, would be captured under problem
#2 (hazardous/toxic air pollutants). While the implications of
CC>2 and global warming (#8) may be large for the ecological
and welfare assessments, no information on how this problem may
increase cancer incidences is known. Finally, no cancer risk
was identified for biotechnology (#29).
22
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The first phase of this exercise involved the compilation
of the results of existing analyses to estimate cancer risks
for each of the remaining environmental problems. In general,
this information was taken from risk assessments performed in
support of specific regulatory activities performed by the Agency.
Individual committee members from each program office took
responsibility for gathering information specific to each
environmental problem. This information was then condensed
into short summaries of the cancer risk information for each of
the environmental problems investigated.
Each of these summaries begins with a short definition of
the nature of the environmental problem, describing the boundaries
and giving examples of the problem to the extent possible.
This is followed by a discussion of the specific contaminants
assessed, and the reasons why these substances were chosen.
Following this introductory material, each summary outlines the
methods by which quantitative risk estimates were developed.
Cancer potencies, where different from the approach taken by.
EPA's Carcinogen Assessment Group (CAG), are presented, along
with an explanation of why a different approach was taken. In
the cases where risk estimates are based on "non-CAG" methods,
comparisons are made to the model used by CAG. Methods used to
estimate exposure are also outlined in this section of the
summary, including the extrapolation from specific exposure
situations to nationwide estimates, whether contaminant concen-
tration estimates are based on measured or modelled data, and
23
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what assumptions are made with respect to human intake of air,
food, or water. The final section of each summary presents the
results of the risk assessment for both population and maximum
individual risk, where possible.
Throughout the summaries, uncertainties and caveats specific
A
to each environmental problem are addressed as they arise in
the discussion. Where there are particular uncertainties
and/or caveats that do not easily fit into the structure of the
summary, they are addressed at the end of the discussion of the
environmental problems.
These summary estimates of cancer risks by problem area
provided an initial basis for ranking the problem areas. The
ranking could not, however, simply follow these quantitative
estimates mechanistically. The estimates fell short of the
ideal in a number of respects.
1. Risk estimates in different program areas were not
directly comparable. They often relied on different
models and reflected differing degrees of conservatism.
Some relied on epidemiologically-developed potency
estimates, some on data from animal studies. Some
estimates were clearly of better quality and more
certain than others.
2. Many of the estimates of risks in a problem area were
incomplete, covering only some of the carcinogens or
some of the exposures comprising the entire problem
area. Some environmental problem areas, such as radon
24
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(#4), were based on nationwide assessments of the issue,
theoretically accounting for 100% of the problem. On
the other hand, the estimate for inactive hazardous
waste (Superfund) sites (#17) was an extremely rough
nationwide extrapolation from limited data, covering
only exposures via drinking water. And for worker
exposure to chemicals (#31), risk estimates were
generated for only four of the thousands of potential
workplace carcinogens, and no attempt was made to develop
a quantitative nationwide risk estimate.
3. Finally, all of the estimates were subject to the massive
and well known uncertainties inherent in quantitative
cancer risk analysis, inter-species comparison, choice, of
*
low dose extrapolation model, estimation of emissions,
ambient concentrations and exposures, etc.
The result was that the work group had to do a great deal of
qualitative weighing of the quantitative evidence in order to
produce a ranking of problem areas.
After the group gathered the quantitative risk estimates,
it reviewed the information presented on each of the environmental
problems. A full-day work group meeting was held. The first
part of this meeting was devoted to a discussion of the information
presented, focusing on specific questions about the methods
used by program offices to estimate risks for each environmental
problem.
25
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The work group then systematically worked through each of
the problems and ranked them as to their relative severity.
The ranking depended upon the available quantitative risk
estimates, a judgment about how risk for an entire problem area
related to the risk for these portions of the problem that had
been covered in the estimates, and a judgment about the quality
and certainty of these estimates. In a number of instances,
the work group ranked problem areas in a manner different than
the quantitative estimates alone would suggest.
The work group based its ranking of environmental problems
primarily on population risk. In general, regulation of environ-
mental problems may be warranted by either high population or
high individual risks. Exposure of large numbers of individuals
to relatively small cancer risks may result in an unacceptable
number of "expected" cancers associated with an environmental
problem. Conversely, very high excess cancer risks to even a
few individuals may prove unacceptable, even if the expected
number of cases is small. The work group decided to recognize
the importance of high individual risks, not in the basic
rankings, but by separately noting those problems with very
high potential risks to individuals.
The first stage of the ranking was performed in terms of
general qualitative categories (i.e., high/medium/low). When a
consensus was reached at this level of specificity, ordinal
ranking of each problem was undertaken, with pairwise comparisons
used within categories to ferret out differences between closely
26
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ranked problems. Following this meeting, the ranking results
were circulated for review by the committee. Work group members
reviewed the results, generated additional information on some
problem areas, and reconvened to produce the final rankings.
27
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Table 2-2
RANK
CATEGORY 1
PROBLEM AREA
Consensus Ranking of Environmental Problem Areas
On the Basis of Population Cancer Risk*
SUBSTANCES/
EXPOSURES INVESTIGATED
COMMENTS
1 Wbrker
(tied) Exposure to
Chemicals
1 Indoor Radon
(tied)
3 Pesticide
Residues on Foods
4 Indoor
(tied) Air Pollutants
Other than Radon
Formaldehyde
Tetrachloroethylene
Asbestos
Methylene chloride
Radon and its decay products
1 Herbicide
3 Fungicides
1 Insecticide
1 Growth regulator
Tobacco smoke
Benzene
p-Dichlorobenzene
Chloroform
Carbon tetrachloride
Tetrachloroethylene
Trichloroethylene
Ranked highest of any single environmental problem,
along with Indoor Radon — based on work group con-
sensus. About 250 cancer cases were estimated
annually from four substances, but workers face
potential exposures to over 20,000 substances.
Individual risk can be very high.
Also ranked the highest. Current estimates are 5,000
to 20,000 lung cancers annually from exposures within
homes. Some of these are a consequence of the joint
action of radon and tobacco smoke. Individual risks
can be very high.
Cancer incidence estimate of about 6,000 annually,
based on exposure to 200 potential oncogens (one-third
of total pesticides In use) — extrapolated from seven
known oncogens. Assessment does not account for so-
called inert materials in pesticides.
Quantitative assessment estimates 3,500-6,500
cancers annually. Environmental tobacco smoke is
responsible for the majority. Risks from organics
estimated on the basis of monitoring 600 U.S. homes.
Individual risks can be very high. Potential for some
double counting with Consumer Exposure to Chemicals
and with Drinking Water.
The five categories represent decreasing magnitude of cancer risk, with Category 1 representing problem areas with
the highest relative risk, and Category 5 representing problem areas for which no cancer risk has been identified.
Problems are also ranked numerically within each category.
-------
IANK
PROBLEM AREA
SUBSTANCES/
EXPOSURES INVESTIGATED
COMMENTS
4
[tied)
Consumer
Exposure to
Chemicals
Hazardous/
Toxic Air
Pollutants
Formaldehyde
Methylene chloride
p-Dichlorobenzene
Asbestos
20 substances, classes
of substances, or
waste streams
The risk from these four chemicals is about 100-135
cancers annually. There are an estimated 10,000 chem-
icals in consumer products. Even though exposures are
generally intermittent, risks are believed to be high,
given the concentrations to which individuals are
exposed. Consumers are exposed through such products
as cleaning fluids, pesticides, particleboard and
other building materials, and numerous asbestos-
containing products. Considerable double counting
with Indoor Air and Other Pesticide Risks.
A quantitative assessment of 20 substances estimates
approximately 2,000 cancer cases annually. This Is a
subset of the large total number of pollutants to
which people are exposed In ambient air. Individual
risks can be very high. Potential for some double
counting with Active Hazardous Waste Sites Municipal
Hazardous Waste Sites, and Contaminated Sludge.
[Category 2J
Depletion of
Stratospheric
Ozone
Hazardous Waste
Sites -
Inactive
Increased UV radiation
(Chlorofluorocarbons,
Halon 1301,
Chlorocarbons)
Trlchloroethylene
Vinyl chloride
Arsenic
Tetrachloroethylene
Benzene
1,2-Dichloroethane
29
Current nonmelanoma and melanoma skin cancer deaths
at 10,000 annually. Ozone depletion projected to
result In steadily increasing risks, with an additional
10,000 annual deaths projected for the year 2100.
This problem is ranked in Category 2 because of the
considerable uncertainties concerning estimates of
future risk. If estimates are correct, would rank
higher. Needs further research.
Nationwide cancer incidence from six chemicals esti-
mated at just over 1,000 annually. Considerable uncer-
tainty, since nationwide risk estimates are based on
extrapolating from 35 sites to about 25,000 sites
nationwide. Individual risks can be very high. Po-
tential for some double counting with Drinking Water.
-------
(VNK PROBLEM AREA
SUBSTANCES/
EXPOSURES INVESTIGATED
COMMENTS
Drinking
Water
Application
of Pesticides
Radiation
Other than
Indoor Radon
Ingestlon and/or
inhalation of 23
substances
1 Herbicide
3 Fungicides
1 Insecticide
1 Growth regulator
Occupational exposures
Consumer products
Industrial emissions
Quantitative assessment estimates about 400-1,000
cancer cases annually, based on home surveys of public
water systems. Most cases are from radon and trihalo-
methanes. Potential for some double counting with
Indoor Radon, Indoor Air Pollution, and several cate-
gories related to contaminated ground water.
Approximately 100 cancers annually estimated by a
method analogous to that used for Pesticide Residues
on Food. Small population exposed, but uniformly
high individual risks.
Risks associated with medical exposures and natural
background levels excluded; would rank higher if
these were Included. Two-thirds of assessed risk
of 360 annual cancers results from building materials.
Individual risks can be very high. Nonlonizing
radiation not considered due to lack of data.
Other
Pesticide Risks
Hazardous
Waste Sites -
Active
Consumer use
Professional exterminator use
Several carcinogens from
each of the following:
Hazardous waste storage tanks
Hazardous waste in boilers/
furnaces
Hazardous waste incineration
Waste oil
Few quantitative estimates available. Consensus
estimate of 150 cancers annually, based loosely on
discussion of termiticide risks. Less data here
than for other pesticide areas.
No nationwide risk estimates are available, but proba-
bly fewer than 100 cases annually. Risk estimates are
sensitive to assumptions regarding the proximity of
future wells to waste sites. Solid waste management
units were excluded from analysis. Individual risks
can be very high. Possible double counting with
Drinking Water and Hazardous/Toxic Air Pollutants.
30
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RANK
PROBLEM AREA
SUBSTANCES/
EXPOSURES INVESTIGATED
COMMENTS
14 Nonhazardous
Waste Sites -
Industrial
Arsenic
1,1,2,2-Tetrachloroethane
Chloroform
Benzene
No analysis of cancer Incidence. Instead, based on the
consensus of the work group. Judged less severe than
hazardous waste, worse than municipal. Potential for
some double counting with Drinking Water.
15
New Toxic
Chemicals
None
Very difficult to assess future uses of new chemicals
and the risks of using chemicals never manufactured.
Consensus was that this problem poses moderate risks.
[Category 3|
16 Nonhazardous
Waste Sites -
Municipal
17 Contaminated
Sludge
Several pollutants/waste streams
from the following:
Municipal landfills
Municipal sludge incineration
Municipal waste Incineration
Up to 22 carcinogens from the
following:
Land application
Distribution and marketing
Landfilling
Incineration
Ocean disposal
Quantitative estimate of about 40 cancers annually.
This estimate does not include risks from municipal
surface impoundments. Potential for some double
counting with Hazardous/Toxic Air Pollutants,
Contaminated Sludge, and Drinking Water.
Analyses and regulatory development are ongoing.
Preliminary results estimate approximately 40 cancers
annually. Most of this risk comes from incineration
and landfilling. potential for some double counting
with Hazardous/Toxic Air Pollutants, Nonpolnt Source
•Discharges to Surface Water, and Nonhazardous Waste
Sites - Municipal.
31
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RANK
PROBLEM AREA
SUBSTANCES/
EXPOSURES INVESTIGATED
COMMENTS
18
Mining Waste
Arsenic
Cadmium
19
Releases from
Storage Tanks
Benzene
20
21
Nonpoint
Source Discharges
to Surface Water
Other
Ground-Water
Contamination
None
Methylene chloride from
septic systems
22
Criteria
Air Pollutants
Lead
Ozone
Particulate matter
Nitrogen oxides
Sulfur oxides
Carbon monoxide
Estimate of 10-20 cancer cases annually largely due to
arsenic. Severity of problem is relatively low because
remote locations expose a relatively small population.
This assessment excludes oil and gas operations.
Individual risks can be very high. Potential for
double counting with Drinking Water.
Preliminary analysis suggests relatively low cancer
incidence « 1 annually), but exposure modeling not as
conservative as several other solid waste problems
(behavior that limits exposure is assumed). Potential
for double counting with Drinking Water.
Judged to be more serious than other surface water
categories, but no quantitative analysis is available.
Generally, risks from other ground-water contamination
are not estimated due to a lack of information with
respect to sources, their locations, and concentration
levels. Individual risks generally less than 10~"6,
with rough estimate of population risk well under 1
case per year. However, this is an estimate of a
small portion of total risk, as we examined one chemi-
cal at just one of many sources (septic systems).
Potential for some double counting with Drinking Water.
This assessment excludes carcinogenic particles and
VOCs (controlled to reduce ambient ozone) , which are
considered under Hazardous/Toxic Air Pollutants.
Ranked relatively low because none of the criteria pol-
lutants has been adequately shown to cause cancer. If
any are shown to be carcinogenic (e.g., lead), or if
VOCs and carcinogenic particles are included in the
definition of Criteria Air Pollutants, this problem
would move to a higher category.
32
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I Category 4|
RANK PROBLEM AREA
SUBSTANCES/
EXPOSURES INVESTIGATED
COMMENTS
23 Direct Point
Source Discharges
to Surface Water
None
No quantitative assessment is available. Only
ingestion of contaminated seafood was considered,
since the impact of drinking water was covered
elsewhere.
24 Indirect,
Point Source
Discharges to
Surface Water
None
Same as above.
25
Accidental
Releases -
Toxics
None
Because of the short duration of personal exposure to
accidental releases, cancer risk judged to be very
small. Long-term effects on ground-water exposures
were not considered here. Non-cancer health effects
are of much greater concern. Nature of substances
and exposures ranks this problem above oil spills.
26 Accidental
Releases -
Oil Spills
None
See above. Oil spills will be of greater concern for
welfare and ecological effects.
33
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I Category 5| (Listed Alphabetically)
PROBLEM AREA
SUBSTANCES/
EXPOSURES INVESTIGATED
COMMENTS
Biotechnology
None
C02 and Global
Warming
None
Dilemma of ranking this problem is similar to that for
new chemicals, but even less information is available.
No known instances of carcinogenic bioengineered
substances.
Cancer is not considered a significant aspect of this
environmental problem. No assessment was undertaken.
Other Air
Pollutants
None
By definition, carcinogenic pollutants in the outdoor
air are considered under Hazardous/Toxic Air Pollutants,
Therefore, no cancer risk was assessed here.
)Not Ranked)
Discharges None
to Estuaries,
Cosatal Waters and
Oceans
Discharges None
to Wetlands
This category represents a conglomeration of other
categories. The work group chose not to rank it to
to minimize double counting.
See Discharges to Estuaries, Coastal Waters, and Oceans,
above.
34
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(2) Non-Cancer Risk
The non-cancer group had to develop a special approach for
ranking the 31 environmental problems reflecting the relative
magnitude of the different non-cancer health risks associated
with each problem. The methodology addressed a number of
complex issues relevant to evaluating non-carcinogenic health
risks.
There are thousands of different chemicals in the environ-
ment that may cause adverse human health effects. Little is
known about the toxicological properties of most of these
chemicals; only a few have good information on health endpoints,
potency and human exposure. Nevertheless, the work group was
interested in all of these factors.
Different chemicals produce different adverse effects,
ranging from effects of lesser concern (e.g., dental mottling
from fluoride in drinking water) to severe ones (e.g., death
from pesticide poisoning). Entirely different health effects
may arise from a single chemical when exposure occurs at different
levels or by different routes. Effects for a given dose may
differ depending on whether the exposure was acute, subchronic,
or chronic. Different individuals may react differently to the
same chemical; some substances at typical ambient concentrations
are of concern only to sensitive subpopulations such as asthmatics
or infants. And, a health effect may even be more specific, fox-
example depending on whether or not the asthmatic is exercising.
35
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In short, to the extent we do have knowledge about non-cancer
health effects from toxic chemicals, it is highly particularized
and difficult to aggregate. In constrast to analyzing cancer
or welfare effects, there is no accepted common denominator
by which to compare different health effects. Because of
thresholds instead in non-cancer does-response functions, we
can make no simplifying linear assumptions to allow us to
aggregate non-cancer effects over time and over people.
EPA has therefore had great difficulty in analyzing non-
cancer health effects, and has not yet been able to develop
the guidelines on how to assess risks from "systemic
toxicants" (i.e., non-cancer effects excluding reproductive,
developmental and mutagenic effects). ,
Most program offices do.not actually assess risks from non-
carcinogens. Instead, they identify a "safe" level for which
no adverse effects are expected to occur in humans. This is
often determined by reducing the no observed adverse effects
level (NOAEL) seen in animals by one or more uncertainty factors.
Most programs aim to control levels down to this "safe" level,
sometimes known as an acceptable daily intake (ADI) or reference
dose (RfD). Most programs merely evaluate the extent to which
a regulatory option prevents exposures above the RfD without an
explicit calculation of risk. This type of analysis may not be
well suited to comparisons of aggregate risks across environmental
problem areas because RfDs for different chemicals may protect
against different health effects that vary widely in their
36
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severity. And, the shape of the dose response function at
levels above the RfD probably varies substantially across
chemicals.
As a result, the non-cancer effects work group had to
break new ground to compare the non-cancer risks associated
with major environmental problem areas. With established
methods and data lacking, the work group relied extensively on
its judgment.
Shortly after starting this project, it became clear to the
work group that the 31 problem areas involved numerous different
substances with the ability to cause numerous different health
effects. There appeared to be no strong pattern to the sorts
of health effects associated with a particular environmental
problem; the association was much stronger between health effects
and specific chemicals, with a problem representing the sum of
the diverse effects caused by its component chemicals. The
work group made an early decision to focus on a limited number
of substances associated with each environmental problem that
are representative of the problem and are reasonably well
understood. The work group would then scale up from the
representative substances to the entire problem.
The work group developed a format for recording existing
data on representative substances. These summary sheets were
prepared for nearly all of the 31 environmental problems. The
summary sheets included the following information:
37
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o A selection of 3-6 substances to represent the environ-
mental problem, and a description of the rationale for
selecting these substances.
o An estimate of the proportion of risk associated with
the entire problem that is accounted for by the selected
substances.
o Data on health endpoints, levels of toxicological
concern (e.g., RfD, NOEL, etc.), ambient concentrations,
exposed populations, incidence and other information
bearing on the magnitude and severity of the risks from
each selected substance.
o Sources and methods for the data on the selected sub-
stances .
The work group aimed to assess the risks from each selected
substance via a logic akin to that used in calculating the
number of cases expected from a chemical:
Exposure x Potency = Incidence
The differing health effects caused by a single substance could
then be aggregated into a total risk from that chemical through
use of a severity index.
The data available on health effects from and exposures to
toxic substances were far from adequate to perform these calcu-
lations in a quantitatively precise way. Exposure or potency
data were frequently not available for the substances of interest.
When data were available, they were of highly variable quality.
They were often generated using different and incompatible pro-
cedures by different programs, and they reflected very different
degrees of conservatism.
The work group added its judgment to these data and developed
a semi-quantitative scoring system with, which to represent key
attributes for each selected substance. Scores were developed
to cover:
38
-------
o The severity of the health endpoints caused by the sub-
stance. Severity indexes have been developed in many
ways, and they are invariably controversial. One
approach that has been used estimates severity in
economic terms, reflecting the lost earning power and
added medical expenses associated with different
diseases. Another approach relies on polling people
about which health effects they would least like to
suffer. For this project, a subcommittee of health
scientists developed a severity index reflecting
primarily a judgment about the extent to which the
health effect was life threatening and secondarily
about whether it was permanent, reversible and manage-
able therapentically.
Over 100 health endpoints associated with the selected
substances were scored from 1 (mild) to 7 (very severe)
through use of this index. A few of the mild health
effects, with scores of 1 or 2, included: non-infectious
herpes, increased liver enzyines, reduced corneal
sensitivity and dental motthing. Some of the severe
health effects with scores of 6 or 7 included: kidney
or liver necrosis, emphysema, teratogenicity and mortality.
This scale of 1-7 was ultimately converted to a scale of
1-4 to be-C9mparable to the other two factors.
o The population exposed to the substance.
The exposed population was converted into a score ranging
from 1 to 4 as follows:
Population score Number of people exposed
1 <1000
2 . 1000 - 100,000
3 100,000 - 10,000,000
4 >10,000,000
o The potency of the substance at the ambient concentration
or dose to which this population is exposed. This
potency was represented by the ratio between the ambient
concentration at which exposure occurs and the RfD for
the substance. The higher this ratio, the greater the
probability of the health effect occurring, or the greater
the potency. This ratio can also be thought of as an
index of the individual risk at a specific ambient
concentration of a substance.
39
-------
Here also a score ranging from 1 to 4 was developed:
Ratio score Ambient dose divided by RFD
1 1-10
2 . 10 - 100
3 100-1 ,000
4 > 1,000
Developing this score also was highly controversial.
The work group implicitly assumed that dose-response
functions for different chemicals have the same shapes
and slopes. In effect, the work group assumed that a
dose of ten times the RFD is twice as bad as a dose of
five times the RFD, no matter what the chemical.
We tried to develop these three scores consistently for all the
selected substances. We used a different method when available
data covered incidence of a health effect from a substance
rather than exposure and potency (for example, when we had data
on numbers of pesticide poisonings or on numbers of deaths from
accidental .releases of toxics).. When data on individual
substances was lacking, the work group used its best judgment
to score a problem area as a whole without reference to its
component substances. In a few other cases when available
information was minimal, the entire problem area was ranked
without developing component scores. Finally, we did not rank
at all some problem areas where we could not,deelop any way to
estimate risks.
We combined these three scores — representing the severity
of the endpoints, the exposed population, and the likelihood of
an effect given an exposure — in various alternative ways to
produce tentative risk rankings of substances and of problem
areas. We paid special attention in sensitivitiy analysis to
40
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ascertaining whether ranking by individual risk would yield
results much different from ranking by population risk. It did
not. In addition, different approaches were used to aggregate
scores from selected substances into scores for an entire
problem. With different approaches, a few problems (hazardous
air pollutants, drinking water, worker and consumer exposures)
moved between the medium and high risk categories. All were
ultimately ranked high.
We reviewed the various tentative rankings of problem
areas and developed our own qualitative ranking of problem
areas that was consistent with most of the tentative rankings.
We assigned problem areas to categories of high, medium or low
non-cancer risks. The available quantitative data underlying
the scores suggest that there is about a 2+ order of magnitude
difference in risk between each sucessive risk category. As a
final step in the ranking, we adjusted the rankings slightly to
reflect the quality of data on each problem and the proportion
of each problem and the proportion of each problem we had
covered with the substances we studied.
41
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Table 2-3
Relative Ranking of Environmental Problem Areas
Problem Area
Level of
Confidence*
% of Problem
Covered*
High Non-Cancer Risks
Criteria air pollutants (#1)
Hazardous air pollutants (12)
Indoor air pollutants - not radon
Drinking water (#15)
Accidental releases - toxics (#21)
Pesticide residues on food (#25)
Application of pesticides (#26)
Consumer product exposure (#30)
Worker exposure to chemicals (#31)
(#5)
High
Medium
Medium
High
High
Medium
High
Medium
High
30-100
<3
30-100
30-100
30-100
<3
3-10
3-10
<3
Medium Non-Cancer Risks
Radon - indoor air (#4) Low
Radiation - not radon (#6) Medium
UV radiation/ozone depletion (#7) Low
Indirect discharges (POTWs) (#10) Medium
Non-point sources (#11) —
To estuaries, coastal waters, oceans (#13) Medium
Municipal non-hazardous waste sites (#18) Medium
Industrial non-hazardous waste sites (#19) Low
Other pesticide risks (#27) Medium
30-100
30-100
30-100
3-10
30-100
10-30
30-100
10-30
Low Non-Cancer Risks
Direct discharges (industrial) (#9)
Contaminated sludge (#12)
To wetlands (#14)
Active hazardous waste sites (#16)
Inactive hazardous waste sites (#17)
Mining waste (#20)
Releases from storage tanks (#23)
Medium
Medium
Medium
Medium
Low
3-10
30-100
10-30
10-30
30-100
Unranked
Other air pollutants (#3) — - —
CO2 and global wanning (#8) —
Accidental releases - oil spills (#22) — —
Other ground-water contamination (#24) — —
New toxic chemicals (#28) — —
Biotechnology (#29) —
* For seme problem areas, the work group did not believe it had sufficient
information to fill out these columns.
42
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(3) Ecological Risk
No generally applicable methodology for evaluating
ecological risk currently exists. The workgroup therefore
undertook to develop a pragmatic methodology for evaluating
ecological risk that incorporated a structured logical
process and featured frequent, open debate among workgroup
members. The development and refinement of methodology
took place over the course of several months as the workgroup
conducted successive rankings of the environmental problems.
This process took place in three phases. The workgroup
began by conducting an initial assessment that included a
redefinition and modification of the list of environmental
problems to be evaluated, and evaluated the risks of those
proble-ms to a set of ecological systems and other objects
of concern. At the end of this phase, at the request of
the workgroup, the Cornell Ecosystems Research Center
convened a panel of scientific experts to conduct an independent
evaluation. While the expert panel determined that, principally
for lack of adequate information, it could not rank the problems
as such, the panel did provide an evaluation of the potential
for effects on ecological systems presented by various
environmental stresses. To do this, the panel prepared a
list of stress agents and a set of ecosystems against which
the potential impacts of the stress agents would be assessed.
The panel also developed and applied the concept of scale of
impact of risk (local ecosystem, region, biosphere).
43
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The workgroup benefitted greatly from this approach and
employed much of it.
In the third phase of activity leading up to its
final ranking, the workgroup settled on the methodology
that it applied for this ranking.
• There follows a more detailed statement of how the
workgroup approached its task and developed a methodology
and rankings of the ecological risks associated with a set
of environmental problems.
o The workgroup modified the initial list of
environmental problems by dropping five which presented
little or no ecological risk (e.g., indoor air pollution);
by combining other problems whose risks could usefully be
assessed together (e.g., all point source discharges to water,
both direct and indirect); and redefining other problems to
account better for ecological risk (e.g., redefining
discharges to estuaries, near coastal waters and wetlands
as physical modification of aquatic habitat). The resulting
list contained 22 problems (Table 3 of the workgroup report).
The workgroup noted that the original list (as well as the
modified list) included disparate and overlapping environ-
mental problems of different magnitudes, and that this tends
to bias the rankings.
o A task that the workgroup addressed early was to
define a set of ecosystems against which the ecological risk
presented by the problems could be evaluated. For its first
44
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ranking, the workgroup developed and used 19 categories of
ecosystems and other objects of ecological concern. In its
final ranking, following the lead of the expert panel, the
workgroup used the panel's reasonably similar breakout into
16 ecosystems of concern (4 freshwater, 3 marine and
estuarine, 4 wetland and 5 terrestrial).
o The expert panel, in its evaluation of the potential
risk to ecosystems, broke out the types of stress agents
associated with the problem list into 26 airborne, waterborne
and other stress agents (for example, waterborne toxic organ-
ics, radionuclides, gaseous phytotoxicants). The workgroup
used this categorization of stress agents in its final ranking,
o As noted above, the panel had developed geographical
scales of potential impact of stress agents. The stress
agents' impacts could be on local ecosystems, on broader
geographical regions or on the entire biosphere. In its
final ranking, the.workgroup applied this scalar concept.
It did not, however, attempt to formulate a precise defini-
tion of the lines between these scalar categories. The
workgroup did not, for instance, set a radius or other
specific boundary between local and regional risk.
o To evaluate and rank the estimated ecological
impacts that actually derive from the 22 problem areas
(as distinct from assessing the potential impact of parti-
cular stress agents on individual ecosystems), problem-
related information was needed concerning the sources and
45
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extent of emissions and discharges from individual problems,
and especially information concerning exposures of ecosystems
created by those problems. Ideally, this would include the
geographical extent and location of exposure, its intensity,
the length and frequency of exposure, and other factors.
For this purpose, papers were prepared for the workgroup
for each of the 22 problems. The workgroup used the infor-
mation and judgments contained in these papers, as well as
its own individual and collective knowledge. It is important
to recognize that the information available was of variable
depth and quality, and weak in many problem areas.
o To assess the ecological risk that derives from
the various environmental stresses presented by an individual
problem, workgroup members were asked to take into account in
their individual ratings the basic changes that environmental
stresses would cause in the structure and functions of the
ecosystems being evaluated, as well as the reversibility of
the impact and time required for the ecosystem to recover
once the stresses were removed. The workgroup did not
settle on a prescriptive or quantitative approach as to the
weight that should be given these factors, or how to sum
up impacts estimated to occur in varying degree across the
range of exposed ecosystems. The individual rankings given
by workgroup members were tabulated according to overall
classifications of high, medium and low. A cluster analysis
of these rankings showed good agreement, and consensus
46
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supporting the final rankings was reached in subsequent
discussion. The workgroup also grouped the environmental
problems according to scale of impact.
0 The workgroup attempted to rank problems with the
high-medium-low groupings. This resulted in dividing the
problems ranked high into three rank groups and the problems
ranked medium into two rank groups. Problems were not
ranked within the six resulting rank groups. Three problems
were not ranked because of the extent of uncertainty as to
the severity of risk.
o The workgroup gave some effort to trying to rank
ecosystems according to their inherent vulnerability to
damage from environmental stresses. The workgroup concluded
that this was not a useful approach. Even though some
ecosystems, tend to have about the same degree of resilience
to different kinds of stresses, many (and perhaps most)
ecosystems react differently to different kinds of stresses.
o To sum up the workgroup approach, the workgroup
evaluated and attempted to rank the ecological risk posed
by 22 environmental problems by estimating the significance
of the impact of those problems on a set of ecosystems and
on broader geographical regions and the biosphere. The
estimated impacts are those that occur under current
conditions of control as a result of exposure to the stress
agents produced by the set of problem sources.
47
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Table 2-4
Suimiary Ranking of Ecological Risks
Rank Environmental
Problem
Rationale for Ranking Position^
Stratospheric ozone
depletion (7)
CC>2 and global
warming (8)
Physical alteration
of aquatic habitats
(13/14)
Mining, nas, oil
extraction and
processino wastes
(20)
Intensity of impact; High (can
severely damage all natural systems,
particularly primary productivity).
Scale of impact; Biospheric
Ecosystem recovery; Recovery period
extremely long; impacts may be
irreversible.
Control; Effective controls require
coordinated, international effort
that will be very difficult to
obtain.
Uncertainty; Effects of ozone
depletion uncertain; ecological
response to global warming is well
characterized. Rate and timing
of the problem is uncertain.
Criteria air
pollutants (1)
Point-source
discharges (9/10)
Nonpoint-source
discharges and
in-place toxics in
sediment (11)
Pesticides (25/27)
Physical risks from problems *13/14
and #?0 are similar, except #20 in-
cludes terrestrial impacts.
Intensity of impact; High (can
both degrade and completely
destroy ecosystem structure and
functions). Mining poses severe
impacts oh water ecosystems.
Scale of impact; Local to regional.
Ecosystem recovery; Physical impacts
are generally irreversible.
Control; Low degree of controll-
ability.
Uncertainty;
High degree of cer-
tainty associated with effects.
While problems fl, #9/10, 11, and
#25-27 do not share ccrnmon charac-
teristics, they are rank-grouped to-
gether.
Intensity of impact; High (tend to
directly affect ecosystem functions
and indirectly affect ecosystem
structure).
Scale of impact; Local and regional.
Ecosystem recovery; Impacts are
generally reversible.
Control; Degree of control varies
among the problems in this rank
group; more controllable than rank
group fl.
Uncertainty; Some uncertainty, but
much is known about these effects.
1
1 Problems are presented in numerical order within each category
of rank; no ranking inference should be made within these categories.
niTmh*a-r«! in rwrpnt-hpcjfat; fnl 1 owinn thp nroblems arp those uspd in
48
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Summary Rankina of Ecological Risks
Rank Environmental
Problem
Rationale for Rankina Position^
Toxic air pollutants
(2)
Intensity of impact; Medium. Grow-
ing evidence to indicate that toxic
air pollutants responsible
for ecological damage.
Scale of impact; Local to regional .
Ecosystem recovery; Unknown.
Control; Unknown, but likely to be
difficult
Uncertainty;
Substantial.
Contaminated sludge
(12)
Inactive hazardous
waste sites (17)
Municipal waste
sites (18)
Industrial non-
hazardous waste sites
(19)
Accidental Releases
of Toxics
(21)
Oil spills (22)
Other ground water
contamination
(24)
These problems overall have localized)
releases and effects |
Intensity of impacts; Medium (many
sources; impacts generally low, but
can be high locally).
Ecosystem recovery; Uncertain.
Control; Variable.
Uncertainty; Moderate
Radiation other
than radon (6)
Active hazardous
waste sites (16)
Underground Storage
tanks (23)
These problems are characterized
by few large releases, a high
degree of control for #6 and f!6.
Intensity of Impacts; usually low
though could be moderate to severe
locally in unusual circumstances.
Scale of Impact; local
Ecosystem recovery; uncertain
Uncertainty; moderate
49
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(4) Welfare Effects
The Welfare Effects work group began by filling out a set of
fact sheets that detailed the types of welfare risks related to each
of EPA's programs. The fact sheets briefly describe each environ-
mental problem, note the studies that have been conducted on
the welfare effects the problem poses, present an estimate of
the damages expected from the problem, and point out any serious
methodological limitations of the studies the damage estimate
is based on. To draw out relevant studies and data and to ensure
the accuracy of the work groups' conclusions, we circulated the
fact sheets to all of the relevant program offices for review and
comment.
Because one goal of this project was to generate cross-
fertilization between program offices, we grouped the fact
sheets by type of welfare effect, instead of along programmatic
lines. The topics we examined encompassed the full range of
welfare effects: soiling and other material damages; recreation;
natural resources; damages to other public and commercial prop-
erty and ground-water supplies, and losses in aesthetics and nonuser
values. These fact sheets formed the basis for the body of the
report.
Before ranking the environmental problems, we established
the following ground rules to ensure consistency in accounting
for the significance of environmental problems:
0 Quantify effects as best as possible. Even when infor-
mation about the extent of effects is sketchy or prelim-
50
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inary, weigh it so that the effects of alternative en-
vironmental problems can be projected.
0 If possible, present a monetary estimate of damages.
A monetary numeraire or unit provides a common basis
for comparing effects across environmental settings.
0 When possible, annualize monetary damages, and convert
them into 1986 dollars.
0 Aggregate damage estimates to a national basis whenever
possible.
0 Evaluate only current and future environmental effects—
not effects that current EPA programs have already elim-
inated. This project is only concerned about ranking
so-called uncaptured, or residual, effects.
0 Rank future effects lower than' present effects, all else
being held constant.
We next ranked the 31 environmental problems. Each member
first ranked the problems separately. Then, based on these
individual rankings, the full work group constructed a composite
ranking of the 31 environmental problems.
The original 31 environmental problems represent an overlap-
ping set of sources, receptors, and pollutants. In many cases,
we had difficulty classifying effects based upon the 31 problems.
For instance, many of the welfare effects from pesticides are
attributed to two environmental problems: Nonpoint Source Dis-
charges to Surface Waters (a source category) and To Estuaries,
Coastal Waters, and Oceans from All Sources (a receptor category)
51
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As a result, the environmental problem Other Pesticide Risks
is ranked lower than if these effects were considered as a sep-
arate source category. Thus, knowing what types of effects are
included in each of the environmental problems is important for
interpreting the rankings.
We also had difficulty ranking environmental problems with
less severe welfare effects. Consequently, we are not confident
of the relative rankings for this group of environmental problems.
Finally, it was not clear how to distinguish "welfare"
effects from "health" or "ecosystem" effects. Often it is dif-
ficult to compartmentalize environmental problems into this set
of categories. Partly, this is the result of the multidimensional
nature of many environmental problems. Also, in many cases, the
scientific literature and economic valuation techniques do not
adequately distinguish effects by these separate categories.
For example, reductions in the property values of residen-
ces close to a hazardous waste disposal site may at first appear
to be welfare losses. In this case, a welfare loss is defined
as a loss in the commercial value of an asset or a good due to
its exposure to an environmental pollutant. However, it could
be argued that the reductions reflect peoples' responses to a
"health" threat. Thus, the case could be made that reductions
in property values indicate the amount people must be compensated
to bear added cancer and noncancer risks and therefore should
be evaluated in the health reports of this project.
52
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Alternatively, suppose that risk assessments indicate that
only small health effects can be documented as a consequence of
the hazardous waste disposal site. This might be the case if many
of the health effects were perceived but could not readily be
identified. In this situation/ it would be less clear as to
whether to attribute the declines in property values to a
"health" effect.
Similarly, problems result when attempting to distinguish
"welfare" from "ecosystem" effects. In many cases, an environ-
mental problem may fall into either type of effects. For in-
stance, acid precipitation may reduce the diversity of forests
(an ecoystem loss), thereby changing animal populations and
limiting hunting opportunities (a welfare loss).
In cases of this sort, this report classifies welfare
effects as tho.se that are likely to result in losses to commer-
cial activity or losses that can be monetized. On the other
hand, ecosystem effects are effects that can be monetized in
theory, but the techniques for doing so are too unreliable to be
particularly useful or meaningful.
Given all the gaps in our knowledge, it was virtually impos-
sible to sort out many of the complicated issues in evaluating
welfare effects. We attempted to characterize welfare effects
as accurately as possible, while explicitly recognizing the many
difficulties associated with an effort of this nature. We gen-
erally included in our assessments welfare effects that are
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intertwined with health and ecosystem affects. Thus, double
counting is likely to be present in the reports of the four
work groups.
54
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Table 2-5
Final Rankings of Welfare Effects Work Group
Rank High Effects
1 Criteria Air Pollutants from Mobile and Stationary
Sources (including acid precipitation)
2 Nonpoint Source Discharges to Surface Waters
3 Indirect Point-Source Discharges (POTWs) to Surface Waters
4 To Estuaries, Coastal Waters, and Oceans from All Sources
5 CC<2 and Global Warming
6 Stratospheric Ozone Depletion
7 Other Air Pollutants (odors and noise)
8 Direct Point-Source Discharges (industrial, etc.) to Surface
Wa t er s
Medium Effects
9 Hazardous Waste Sites — Inactive (Superfund)
10 Nonhazardous Waste Sites — Municipal
11 Hazardous Waste Sites — Active (RCRA)
12 To Wetlands from All Sources
13 Other Pesticide Risks — leaching and runoff of pesticides
and agricultural chemicals, air deposition from spraying,
etc.
14 Biotechnology
Low Effects
15 Nonhazardous Waste Sites — Industrial
16 Releases from Storage Tanks (including product and petro-
leum tanks that are above, on, and underground)
17 Accidental Releases of Toxics
18 Accidental Oil Spills
19 Drinking Water as It Arrives at the Tap
20 Radon — indoor only
21 Mining Wastes (including oil and gas extraction wastes)
22 Contaminated Sludge
23 Hazardous/Toxic Air Pollutants
Minor Effects
Other Ground Water Contamination
Radiation Other Than Radon
. Indoor Air Pollutants other than Radon
Pesticide Residuals on Foods Eaten by Humans
Applicators of Pesticides (risks to applicators and con-
sumers)
New Toxic Chemicals
Consumer Product Exposure
Worker Exposure to Chemicals
Includes effects from Pesticides.
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CHAPTER III
SUMMARY OF WHAT WE LEARNED ABOUT THE 31 ENVIRONMENTAL PROBLEMS
This chapter summarizes and brings together the findings
of the four work groups concerning each of the thirty-one
environmental problems studied. For a full understanding of the
information presented here, as well as references on which it is
based, the reader is directed to the four work group reports.
The information on public opinion is explained in Chapter IV.
Several other points should also be remembered when reading
this chapter:
0 Each group looked at risks existing now, given existing
controls, and not at inherent risks or at risks that
have been or could be controlled. Existing controls
are assumed to be maintained. This is a key assumption.
Many environmental problems show up in this analysis
as posing moderate or relatively low risks precisely
because extensive controls are in place and are being
maintained, often at considerable expense.
0 All of the work groups ranked problems in general cate-
gories, such as relatively high, medium or low. (The
reader should note that the ecological group called
the first three of their six rank groupings "relatively
high", groups four and five "medium" and group six
"relatively low".) In addition, two of the groups,
cancer and welfare, ranked problems ordinally. The
reader is cautioned not to place great weight on the
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precision that may appear to be implied between
closely ranked problems. In various cases, further
study might cause the the rankings of closely-ranked
problems to be reversed. However, the work groups
are confident in the differences implied by rankings
that are farther apart.
0 HOW we divided up the universe of environmental
problems significantly affected the ranking of the
problems - the broader the category the more impacts
it covers, and vice-versa. As noted earlier, there are
also substantial overlaps among the thirty-one problems.
The reader is reminded that the universe of environmental
problems was divided the way it was because the project
participants felt that these categories most closely
approximate how people generally think of the problems.
Also, while the work groups generally used the same
definitions of categories, they did not always do
so; the major cases where this happened are noted.
0 The rankings of the different environmental problems
are based on the risks to the entire U.S. population
in terms of total incidence of disease, etc. Where
risks to individuals (as opposed to the population
at large) can be relatively high, that is noted.
It is important to understand that because local
situations vary widely, the risks faced by any
particular individual or community probably do not
rank the same as shown here.
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1. Criteria Air Pollutants
Description of Problem
The criteria air pollutants are sulfur dioxide, total suspended
particulates, carbon monoxide, nitrogen oxides, ozone, and lead.
Acid precipitation is included in this problem area. Major
sources of these pollutants are combustion from motor vehicles,
electrical utilities, and industrial boilers and smelters.
Cancer Risks
Ranked in category 3 of 5 (#22 of 29).
Ranked low because none of the criteria pollutants has been
adequately shown to cause cancer. If any shown to be carcinogenic
(e.g., lead), it would move this problem to a much higher category
due to high population exposure. This assessment excludes
carcinogenic particles and volatile organic compounds, considered
under #2. (Hazardous/Toxic Air Pollutants).
Non-cancer Health Risks
Relatively high risk. High level of confidence in data/judgment,
compared with other problems examined.
Large populations exposed, with moderate to severe health effects.
Ranked relatively high, mostly on -the basis of ozone and acid
aerosols. Large numbers of people exposed to ozone at levels
far above safe levels. Large numbers of people exposed to acid
aerosols, with increased mortality possible.
Ecological Effects
Relatively high risk (#3 out of 6 rank groupings).
Scale of impact - regional.
Acid deposition and ozone most important.
Risks tend to affect ecosystem functions and structures.
Impacts not considered irreversible, except for impacts of ozone
on forests and natural ecosystems.
Some uncertainty, but a fair amount is known about ecological effects.
Welfare Effects
Ranked relatively high (#1 of 31).
Multiple damage categories have been documented: materials damage
and soiling to residential, industrial, and commercial property;
visibility impairment; decreased sportfishing; reduced crop
and forest yields. Materials damages estimated at over $20
billion/year. Damages are immediate, ongoing, and tangible.
Comments
Compared with other environmental problems, these are well analyzed
and understood. The public rates air pollution as a serious
risk, but behind chemical waste disposal, water pollution, and
chemical plant accidents.
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2. Hazardous/Toxic Air Pollutants
Description of Problem
This problem area covers outdoor exposure (primarily through in-
halation) to toxic and hazardous air pollutants. For purposes
of this project, to the extent possible, this category excludes
risks from pesticides, radioactive substances and chlorofluoro-
carbons. It includes emissions from treatment, storage, and
disposal facilities, chemical plants, motor vehicles, metallur-
gical processes, and sewage treatment plants.
Cancer Risks
Ranked in category 1 of 5 (#6 of 29). Individual risk can be
relatively high.
Ranked high largely as a result of quantitative assessment of
approximately 2,000 cases annually from 20 substances. Large
total number of pollutants to which people are exposed in
ambient air.
Non-cancer Health Risks
Relatively high risk. Medium level of of confidence in data/
judgment, compared with other problems examined. Ranked high
although only a^small "proportion of the problem was covered
by the substances studied.
Large exposed populations, but effects are often not severe
(e.g., general pulmonary irritation). .
Ecological Effects
Relatively medium risk (#4 out of 6 rank groupings).
Scale of impact - regional.
Growing evidence of adverse regional impacts (e.g., Great Lakes),
though substantial uncertainty exists.
Recovery period - years to decades.
Substantial uncertainty (most of data developed have been for
human health).
Welfare Effects
Ranked relatively low (#23 of 31).
Comments
This problem is not as well understood as criteria air pollutants,
Cancer is responsible for much of the attention it receives.
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3. Other Air Pollutants
Description of Problem
This group of air pollutants includes sulfuric acid mist,
total reduced sulfur, fluorides and odor-emitting substances
not included under problem areas #1 and #2, and noise.
Cancer Risks
Ranked in category 5 of 5 (no cancer risk identified). By
definition, carcinogenic pollutants in the outdoor air are
considered under #2 (Hazardous/Toxic Air Pollutants).
Non-cancer Health Risks
Not ranked. Thought to be quite a low risk compared with other
problems examined.
Principal health effect is stress.
Ecological Effects
Not ranked. No significant risks to ecosystems.
Welfare Effects
Ranked relatively high (#7 of 31).
Over half the complaints received by state and local environmental
agencies concern odors and noise; large exposed populations,
particularly in urban areas.
Difficult to place monetary value on this probl-em, but value
appears to be very significant.
Comments
These problems have been largely ignored at the federal level,
in favor of others that pose larger health risks.
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4. Radon - Indoor
Description of Problem
Radon is a radioactive gas produced by the decay of radium,
which occurs naturally in almost all soil and rock. It migrates
through the soil into buildings, where it is trapped by dense
building materials. The decay products of radon, called radon
daughters, can cause lung cancer. This category covers indoor
radon only. Outdoor concentrations of radon are far lower.
Cancer Risks
Ranked in category 1 of 5 (tied for #1 of 29). Individual risk
can be relatively high.
Current estimates of 5,000 to 20,000 lung cancers annually. Some
of these cancers caused by the joint action of radon and to-
bacco smoke.
Non-cancer Health Risks
Relatively medium risk. Low level of confidence in data/judgment,
compared with other problems examined.
Ranking derives from incidence modeling.. Effects are related to
cancer. Perhaps 200 cases per year of serious mutagenic and
teratogenic effects. Very large population exposed. Effects
are severe-, but their probability is low.
Ecological Effects
Not ranked. No ecological effects.
Welfare Effects
Ranked relatively low (#20 of 31).
Could require average of $1 ,000-$! ,500 modification per house for
many houses or cause equivalent lowering in property values. But
counting dollar costs for remedies may double-count the health
risks by capitalizing the costs of their control.
Comments
Serious health problem in certain areas. Different from most other
environmental problems, because individuals must decide to spend
their own money on their homes.
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5. Indoor Air Pollution Other Than Radon
Description of Problem
This category applies to indoor air pollutants (except radon)
from sources in buildings (e.g., unvented space heaters and
gas ranges, urea-formaldehyde foam insulation, pesticides,
tobacco smoke, wood presevatives, fireplaces, solvents from
cleaning and waxing agents). Pollutants that are indoors as a
result of diffusion from outdoors are not included, unless
indoor levels are a function of the building itself (e.g., poor
ventilation). Some risks are double counted with those from
Consumer Product Exposure (#30), Other Pesticide Risks (#27)
and Drinking Water (#15).
Cancer Risks
Ranked in category 1 of 5 (tied for #4 of 29). Individual
risk can be relatively high.
As people spend most of their time indoors and are exposed to
a number of substances from a variety of sources, the risk
is judged relatively high. Quantitative assessment indicates
3,500-6,500 cancers annually, with passive smoking responsible
for the majority. Risks from organic chemicals estimated on
.the basis of monitoring 600 U.S. homes.
Non-cancer Health Risks
Relatively high risk. Medium level of confidence in data/judgment,
compared with other problems examined.
Large populations exposed above level of concern. Effects are
moderate to severe (from jaundice to teratogenicity and
mortality). Ambient levels are often substantially above
reference doses. Environmental tobacco smoke thought to
contribute the largest portion of total risk.
Ecological Effects.
Not ranked. No ecological effects.
Welfare Effects
Ranked as relatively minor. Not ranked numerically.
Comments
Important health problem, although not generally recognized as such
by the public. For a variety of reasons (statutory, multitude
of sources, difficulty of control, etc.), this has not been
a major EPA priority.
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6. Radiation from Sources Other Than Indoor Radon
Description of Problem
Occupational and consumer exposure to ionizing and nonionizing
radiation (beyond natural background) are included here. Increased
radiation from stratospheric ozone depletion/UV light is included
in problem area #7. Medical exposures not counted.
Cancer Risks
Ranked in category 2 of 5 (#11 of 29). Individual risk can be
relatively high.
Did not consider medical exposures and natural background levels,
which could cause 10,000 cases/year; thus, would rank higher if
these were included. Two-thirds of assessed risk of 360 annual
cases from building materials. No information available on
nonionizing radiation.
Non-cancer Health Risks
Relatively medium risk. Medium level of confidence in data/
judgment, compared with other problems examined.
Ranking derives from incidence modeling;- perhaps 200 serious
mutagenic and teratogenic effects per year. Very large
populations exposed to radiation; effects can- be severe, but
their probability is low. Incidence might increase by a factor
of 15 if medical X-rays are counted. Nonionizing radiation not
considered.
Ecological Effects
Relatively low risk (#6 out of 6 rank groupings).
Scale of impact - local.
Many uncertainties.
Welfare Effects
Ranked as relatively minor. Not ranked numerically.
Comments
Medical radiation risks (not subject to EPA regulation) are best
understood and accepted. Together with natural background
radiation they constitute the bulk of radiation most people
receive.
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7. Substances Suspected of Depleting the Stratospheric
Ozone Layer
Description of Problem
The stratospheric ozone layer shields the earth's surface from
harmful ultraviolet (UV-B) radiation. Releases of chlorofluoro-
carbons (CFCs) and nitrogen dioxide from industrial processes
and solid waste sites could significantly reduce the ozone layer.
Cancer Risks
Ranked in category 2 of 5 (#7 of 29).
Current analysis projects that fatal skin cancers could rise
steadily to perhaps an additional 10,000 per year in 2100.
Considerable uncertainties concerning future estimates; would
rank higher in future if projections are correct.
Non-cancer Health Risks
Relatively medium risk. Low confidence in data/judgment,
compared with other problems examined.
Principal non-cancer effects are (1) cataracts (1% ozone depletion
estimated to increase cataracts by 10,000-30,000/year); and (2)
adverse effects on immune system (effects not estimated).
Ecological Effects
Relatively high risk (#1 out of 6 rank groupings).
Scale-of impact - biosphere.
Could affect all natural systems, particularly primary pro-
ductivity systems (e.g., phytoplankton). Recovery period
extremely long, if recovery is possible at all. Effective
controls require coordinated international effort. Severity
of impact more than offsets uncertainties, which are considerable.
Welfare Effects
Ranked relatively high (#6 of 31).
Value of crop, livestock, and fish species at risk is very high.
Considerable uncertainty surrounding (1) UV-B dose-response
relationships for different species and (2) projections for
ozone depletion.
Comments
Issue of uncertainty is important, but risks are potentially
very significant. While the issue has recently received
some attention in the press, it is not well understood by
the public.
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8. CC>2 and Global Wanning
Description of Problem
Atmospheric concentrations of carbon dioxide (C02) are projected
to increase over the next century due to an increase in fossil
fuel combustion and a decrease in tropical forests. Higher
levels of C02 may raise climatic temperatures globally, raising
the sea level.
Cancer Risks
Ranked in category 5 of 5 (no cancer risk identified).
Cancer not considered a significant aspect of this environmental
problem. Thus, risk not assessed.
Non-cancer Health Risks
Not ranked.
Global warming would change heat stress and disease patterns.
Ecological Effects
Relatively high risk (#1 out of 6 rank groupings).
ScaJ.e ofo impact - biosphere.
1.5 -4.5 warming in next 50-75 years would raise sea level and
alter the hydrological cycle, affecting all natural systems,
particularly primary productivity systems. Recovery period
is extremely long, if possible at all. Effective controls
would require very significant coordinated international
effort.
Welfare Effects
Ranked relatively high (#5 of 31).
Sea level rise threatens large investment in urban infrastructure
and both urban and rural lands. Changes in weather patterns
could also cause substantial welfare effects. Some positive
effects (e.g. on crop yields) possible in some areas.
Considerable uncertainty with magnitude of projected effects.
The speed with which they occur is also important.
Comments
Issue of uncertainty is important, but risks are potentially very
significant. In addition to the risks described here, geopolitical
risks are potentially serious. Partly because the risks are
in the future and partly because they are difficult to understand,
the public is not strongly concerned.
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9. Direct, Point Source Discharges to Surface Waters
Description of Problem
"Point sources" are specific stationary sources of pollution,
such as industrial plants which directly discharge toxic,
acidic, and organic waste effluents into rivers, lakes, and
coastal areas. Category excludes POTW's (#10). Substantial
double-counting with #13-estuaries, near-coastal waters and
oceans.
Cancer Risks
Ranked in category 4 of 5 (#23 of 29).
No quantitative assessment available. Only ingestion of contaminatec
seafood considered; drinking water impacts covered under #15.
Non-cancer Health Risks
Relatively low risk. Medium confidence in data/judgment, compared
with other problems examined.
Risks from consumption of fish and shellfish that have bioaccumulatec
toxics or that are contaminated by pathogens thought to be
generally low. Risks from consumption of drinking water
contamined by surface water discharges thought to be minimal.
Ranked without data on specific substances.
Ecological Effects
Relatively high risk (#3 out of 6 rank groupings).
Scale of impact - regional.
Direct and indirect point sources (problems #9 and #10)
release more toxics than any other sources and are major
contributors of other pollutants.
Points sources have impaired or otherwise affected ecosystems
in 41% of 328,000 stream miles analyzed; 15% of lakes; 49%
of estuaries; 58% of coastal waters.
(Grouped with #10)
Welfare Effects
Ranked relatively high (#8 of 31).
Losses to recreational uses of surface waters (e.g. swimming,
fishing, boating) estimated at $800 million/year. Commercial
fishing yields can be reduced. Damages generally of the
same type as nonpoint and indirect point sources (#10, #11),
but less.
Comments
Low health risks due to extensive controls and the assumption
that they stay in place (worldwide, a large proportion of
diseases are waterborne). The public ranks water pollution as
high risk, second only to chemical waste disposal.
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10. Indirect, Point Source Discharges (POTWs) to Surface
Waters
Description of Problem
Includes the discharges from specific points of pollution, after
passing through municipal sewage treatment systems (Publicly
Owned Treatment Works - "POTW's") into fresh, brackish or marine
waters.
Cancer Risks
Ranked in category 4 of 5 (#24 of 29).
No quantitative assessment available. Only ingestion of contaminated
seafood considered; drinking water impacts covered under #15.
Non-cancer Health Risks
Relatively medium risk. Medium confidence in data/judgment, compared
with other problems examined.
Ranked without data on specific substances.
Problem considered mostly to be ingestion of seafood contaminated
with pathogens from inadequate sewage treatment.
Ecological Effects
Relatively high risk (#3 out of 6 rank groupings).
Scale of impac't - regional.
Direct and indirect point sources (problems #9 and #10) release
more toxics than any other sources and are major contributors
of other pollutants. Point sources have impaired or otherwise
affected ecosystems in 41% of 328,000 stream miles analyzed;
15% of lakes; 49% of estuaries; 58% of coastal waters.
Welfare Effects
Ranked relatively high (#3 of 31).
Important contributor to loss of recreational uses of surface
water (e.g. swimming, fishing, boating) — estimated at $2.4
billion/year. Commercial fishing yields can be reduced.
Damages generally similar to those from non-point source
discharges to surface waters (#11), but somewhat less.
Comments
Low/medium health risks due to extensive controls and the
assumption that they stay in place (worldwide, a large proportion
of diseases are waterborne). The public ranks water pollution
as high risk, second only to chemical waste disposal.
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11. Nonpoint Source Discharges to Surface Water
Description of Problem
Includes pollutants that reach fresh, brackish or marine waters
from such nonspecific sources as rainwater runoff of pesticides,
herbicides and fertilizers from the land; infiltration from
ground water; and air pollutants that settle into the water.
Cancer Risks
Ranked in category 3 of 5 (#21 of 29).
Judged to be more serious than other surface water categories ,
but no quantitative analysis is available.
Non-cancer Health Risks
Relatively medium risk.
Moderate concern for bacteriological contamination of shellfish
and other fish from agricultural and urban runoff. Some
concern for runoff and bioaccumulation of pesticides and
other toxics in shellfish and other fish.
Ranked without data on specific substances.
Ecological Effects
Relatively high risk (#3 out of 6 rank groupings).
Scale of impact - regional.
Analysis includes in-place toxicants in sediments.
Ubiquitous problem affecting water quality in streams that
do not have sufficient dilution to recover rapidly. However,
since releases are not continuous, ecosystems may recover more
quickly than from chronic, low-level releases from point
sources.
Welfare Effects
Ranked relatively high (#2 of 31).
Major contributor to loss of recreational uses of surface waters
(e.g., swimming, fishing, boating) -- estimated at $3.6 billion/
year. Runoff can also decrease crop yields and downgrade
agricultural lands.
Comments
Hard data on this problem are not as good as for some other
problems. The public ranks water pollution as high risk,
second only to chemical waste disposal.
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12. Contaminated Sludge
Description of Problem
Sludge is generated by various sources, such as municipal
sewage treatment plants and scrubbers used as pollution control
devices. It may be recycled, impounded, landfilled, land-spread,
dumped in the ocean or incinerated. Some double counting with
Hazardous/Toxic Air Pollutants (#2), Nonpoint Sources (#11) and
Non-Hazardous Municipal Waste Sites (#18).
Cancer Risks
Ranked in category 3 of 5 (#17 of 29).
Preliminary analysis estimates several dozen cases annually,
primarily from incineration and landfilling.
Non-cancer Health Risks
Relatively low risk. Medium confidence in data/judgment, compared
with other problems examined.
Human exposure to contaminants in sludge thought to'be indirect
and extremely limited.
Ecological Effects
Relatively medium risk-(#5 out of 6 rank, groupings).
Scale of impact - local.
Extensive damage not expected to natural ecosystems, where
current plus reasonably anticipated control programs are
properly implemented. However, the risk could be high
locally if programs are not properly implemented. .
Welfare Effects
Ranked relatively low (#22 of 31).
Disposal usually takes place in isolated areas.
Comments
Data on impacts are limited.
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13. Discharges to Estuaries, Coastal Waters, and Oceans
from All Sources
Description of Problem
This problem area includes a wide variety of pollutants and
sources that reach such waters. Likely double counting with
criteria air pollutants (#1); toxic air pollutants (#2); dis-
charges from point (#9, #10) and nonpoint (#11) sources;
sludge (#12); active (#16) and inactive (#17) hazardous waste
sites; municipal (#18) and industrial (#19) nonhazardous waste
sites; mining waste (#20); accidental releases of toxic pollu-
tants (#21); oil spills (#22); releases from storage tanks
(#23); and risks from pesticides (#27).
Cancer Risks
Not ranked. Because this category represents a conglomeration
of other categories, the work group decided not to rank it to
avoid double counting.
Non-cancer Health Risks
Relatively medium risk.
Moderate concern over consumption of fish and shellfish contaminated
with pathogens, pesticides and other toxics. Large numbers of
people exposed.
Ranked without data on specific substances.
Ecological Effects
Work group combined this problem with #14 and redefined it as
"hydrological modification."
New category ranked as relatively high risk (#2 out of 6 rank
groupings).
Scale of impact - regional.
Can result in profound, generally irreversible, physical destruction
of ecosystems.
Difficult to control.
High degree of certainty.
Welfare Effects
Ranked relatively high (#4 of 31).
Damages include reductions in recreational uses and in commercial
harvests of shellfish and other seafoods.
Damages have been estimated at $150-$500 million annually for six
major estuaries, but no attempt has been made to extrapolate
these figures to a national damage estimate.
Comments
This problem sometimes does not get the attention that others get
because direct health risks are not dramatic. Ecological and
welfare problems are the most important aspects.
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14. To Wetlands from All Sources
Description of Problem
This problem area includes all risks from pollutants reaching
wetlands. It includes double counting with criteria air
pollutants (#1); toxic air. pollutants (#2); discharges from
point (#9, #10) and nonpoint (#11) sources; sludge (#12);
active (#16) and inactive (#17) hazardous waste sites; municipal
(#18) and industrial (#19) nonhazardous waste sites; mining
waste (#20); accidental releases of toxic pollutants (#21);
oil spills (#22); releases from storage tanks (#23); and risks
from pesticides(#27).
Cancer Risks
Not ranked. Because this category represents a conglomeration of
other categories, the work group decided not to rank it to
avoid double counting.
Non-cancer Health Risks
Relatively low risk.
Minimal concern over consumption of contaminated food or water
from wetlands. Exposure to contaminated food thought to be
considerably less than from estuaries.
Ranked without data on specific substances.
Ecological Effects
Work group combined this problem with #13 and redefined it as
"hydrological modification."
New category ranked as relatively high risk (#2 out of 6 rank
groupings).
Scale of impact - regional.
Can result in profound, generally irreversible, physical destruction
of ecosystems.
Impacts generally irreversible.
Difficult to control.
High degree of certainty.
Welfare Effects
Ranked relatively medium (#12 of 31).
Sizable quantities of harvestable shellfish and wildlife at risk.
Damages are similar to those to estuaries, coastal waters, and
oceans (ranked #4), but commercial products of wetlands and
swimming are more limited.
Comments
This problem sometimes does not get the attention that others
get because direct health risks are not dramatic. Ecological
problems are the most important aspect.
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15. Drinking Water As It Arrives at the Tap
Description of Problem
As drinking water arrives at the tap, it may contain a wide variety
of volatile and synthetic organic contaminants, such as pesticides,
lead from pipe corrosion, several organic chemicals falling under
a group known as trihalomethanes, and several natural and man-
made radionuclides, including radon. There may be some double
counting of risks from this problem with those from Radon (#4) ,
Indoor Air (#5), and several categories related to ground water
contamination.
Cancer Risks
Ranked in category 2 of 5 (#9 of 29).
Cancer risks principally from disinfection by-products and
radon.
Quantitative assessment estimate of 400-1000 cases annually,
based on surveys of public drinking water systems.
Non-cancer Health Risks
Relatively high risk. High confidence in data/judgment,
compared with other problems examined.
Generally very large exposed population. Serious health
effects (neurotoxicity, mortality) are possible,'but
exposures are not often far above levels of concern. Primary
concerns are over disinfection by-products, lead, and
pathogens.
Ecological Effects
Not ranked because this is not an ecological problem.
Welfare Effects
Ranked relatively low (#19 of 31).
Corrosive water damages municipal water systems and household
plumbing.
Comments
Concerns over chemical waste disposal, various forms of surface
and ground-water pollution, and lead in drinking water have
raised the public profile of this problem, but still not to
the levels of many other environmental problems. It is
important to note that on a national scale our analysis shows
that most of the health risks result from contaminants from
sources other than waste disposal, a belief that does not
appear to be shared by the general public.
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16. Hazardous Waste Sites - Active
Description of Problem
This category generally includes the risks posed by active
hazardous waste sites regulated under the Resource Conservation
and Recovery Act (RCRA). More specifically, it includes RCRA
landfills and surface impoundments (both open and closed),
hazardous waste storage tanks, hazardous wastes burned in
boilers and furnaces, hazardous waste incinerators, waste oil
and solid waste management units. Seepage and releases of
substances from these sources contaminate surface and ground
water and pollute the air. There is potential double counting
of the risks from this problem with those from Drinking Water
(#15) and Hazardous/Toxic Air Pollutants (#2).
Cancer Risks
Ranked in category 2 of 5 (#13 of 29). Individual risks can be
relatively high.
Data very spotty.- Extremely difficult to extrapolate to national
estimate, but most likely fewer than 100 cases annually.
Risk estimates are sensitive to assumptions regarding proximity
of future wells to waste sites.
Solid waste management units were excluded from analysis.
Non-cancer Health Risks
Relatively low risk. Medium confidence in data/judgment, compared
with other problems examined.
Very low number of humans potentially exposed around active
hazardous waste sites. Exposure concentrations for non-
carcinogens also thought to be low relative to levels of
concern. Substances involved are generally of moderate
toxicity.
Ranked without data on specific substances.
Ecological Effects
Relatively low risk (#6 out of 6 rank groupings).
Scale of impact - local.
Most sites probably adequately controlling releases to ecosystems
(although problems can result if not properly controlled).
Welfare Effects
Ranked relatively medium (#11 of 31).
Sites can threaten nearby drinking water supplies and thus
depresses property values in vicinity. Effects similar to
inactive hazardous waste sites (ranked #9), but better controls
are expected for new wastes in the future.
No monetary estimates of national impact exist.
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Comments
The public is more concerned about chemical waste disposal than
any other environmental problem. While health data are very
spotty, total health impacts do not appear to match public
concern in most areas. The importance of this problem, especially
as it relates to public concerns, may not be fully reflected in
the risk categories studied in this project.
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17. Hazardous Waste Sites - Inactive (Superfund)
Description of Problem
This category includes Superfund sites that have reached any of
the following stages: discovery, removal, preliminary assessment,
site investigation, placement on the National Priorities List,
remedial investigation, feasibility study, record of decision,
remedial action, deletion. It also includes sites that states
are addressing if they do not already fit into any of the categories
listed above. As with active hazardous waste sites, these sites
may contaminate ground and surface water, threaten nearby residents
with exposure to toxic chemicals, and pollute the air. There may
be some double counting of the risks from this problem with those
from drinking water (#15) and hazardous air pollutants (#2).
Cancer Risks
Ranked in category 2 of 5 (#8 of 29). Individual risk can be
relatively high.
Nationwide cancer incidence estimated at just over 1 ,000 cases
annually on the basis of 6 chemicals. Considerable uncertainty
since nationwide estimates are based on extrapolation from 35
sites to estimate of 25,000 total in the U.S.
Non-cancer Health Risks
Relatively low risk. Medium confidence in data/judgment, compared
with other problems examined.
Moderate number of people potentially exposed around inactive
hazardous waste sites, but exposure concentrations for non-
carcinogens thought to be usually low relative to levels of
concern. Substances involved are generally of moderate
toxicity.
Ranked without data on specific substances.
Ecological Effects
Relatively medium risk (#5 out of 6 rank groupings).
Scale of impact - local. (Effects could be regional, depending on
quantity and toxicity of contaminants and potential for
migration.)
Estimated that 6% of sites are likely to significantly damage
natural resources (wetlands, fisheries, etc.).
Lack of data makes it difficult to assess overall ecological
effects.
Welfare Effects
Ranked relatively medium (#9 of 31).
Sites can threaten nearby drinking water supplies and can depress
property values in vicinity. Effects are usually localized,
most sites are not close to major urban populations or their
drinking water supplies, and alternative water supplies often
exist.
No monetary estimates of national impact exist.
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Comments
The public is more concerned about chemical waste disposal than any
other environmental problem. While health data are very spotty,
total health impacts do not appear to match public concerns
.in most areas. The importance of this problem, especially as
it relates to public concerns, may not be fully reflected in
the risk categories studied in this project.
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18. Nonhazardous Waste Sites — Municipal
Description of Problem
Consists primarily of 16,000 open and closed municipal landfills,
municipal sludge and refuse incincerators and municipal surface
impoundments, which contaminate ground and surface water and
pollute the air. There is potential double counting of the
risks from this problem with those from Hazardous/Toxic Air
Pollutants (#2), Contaminated Sludge (#12), and Drinking Water
(#15).
Cancer Risks
Ranked in category 3 of 5 (#16 of 29).
Very difficult to estimate national impact: quantitative estimate
of about 40 cases per year.
Estimate excludes municipal surface impoundments.
Non-cancer Health Risks
Relatively medium risk. Medium confidence in data/judgment,
compared with other problems examined.
Large number of people potentially exposed, due to large number
of such sites and proximity to populations. Exposure concen-
trations thought to be very low relative to levels of concern
because of low concentration of hazardous constituents -in
such sites and indirect routes of exposure. Substances in-
volved are generally of moderate toxiclty.'
Ranked without reference to specific substances.
Ecological Effects
Relatively medium risk (#5 out of 6 rank groupings).
Scale of impact - local.
Ecosystems can be affected directly by surface water runoff and
generation of gases; wastes can also enter surface'waters
indirectly via ground water.
Sheer number of sources (over 16,000) is largely responsible for
medium ranking (as opposed to severity of risks at most sites).
Welfare Effects
Ranked relatively medium (#10 of 31).
Sites can threaten nearby drinking water supplies and depress
local property values. Property value effects are hard to
measure because other facilities, such as industrial plants,
are often nearby and can also have the same effect.
No monetary estimates of national impact exist.
Comments
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19. Nonhazardous Waste Sites - Industrial
Description of Problem
There are about 3,400 nonhazardous industrial landfills, 15,000
industrial surface impoundments, and 120,000 oil and gas waste
impoundments throughout the country. This category includes
nonhazardous wastes from the food industry, slaughterhouses,
iron and steel industry, utilities, and the chemicals industry.
There is some potential for double counting the risk from this
category with those from Drinking Water (#15).
Cancer Risks
Ranked in category 2 of 5 (#14 of 29).
No analysis of cancer incidence exists, so ranked on the basis
of committee consensus: less severe than hazardous waste,
more severe than municipal non-hazardous waste.
Non-cancer Health Risks
Relatively medium risk. Low confidence in data/judgment,
compared with other problems examined.
Moderate number of people potentially exposed. Exposure concen-
trations may not always be low relative to level of concern
because wastes are concentrated in these sources and controls
are often" not extensive. 'Substances involved are generally
of moderate toxicity.
Ranked without reference to specific substances.
Ecological Effects
Relatively medium risk (#5 out of 6 rank groupings).
Scale of impact - local.
Ecosystems can be affected directly by surface water runoff and
air emissions; wastes can also enter surface water indirectly
via ground water.
Sheer number of sources is largely responsible for medium
ranking (as opposed to severity of risks at most sites).
Welfare Effects
Ranked relatively low (#15 of 31).
Leachates not as damaging to local ground-water supplies
as are hazardous chemicals or toxics.
Comments
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20. Mining Waste (Includes Oil and Gas
Extraction Wastes)
Description of Problem
This category includes the risks posed by mining operations,
wastes from oil and gas extraction and benefication (which
dominate most of this category), and wastes from smelting
and refining processes. Major contaminants include acid mine
drainage, toxic inorganics, nutrients, turbidity, oils, and
solids. There is some potential for double counting of the
risks from this problem with those from Drinking Water (#15).
Cancer Risks
Ranked in category 3 of 5 (#19 of 29). Individual risk can be
relatively high.
Principal risks analyzed were from smelting and refining wastes
(oil and gas operations excluded). Estimate of 10-20 cases
annually largely due to arsenic. Severity of problem is
relatively low because remote locations expose relatively low
population.
Non-cancer Health Risks
Relatively low risk. Low confidence in data/judgment, compared
with other problems examined. .
Low number of people potentially exposed due to distance of sites
from population. Low concentrations when exposure does occur.
Substances have low toxicity.
Ranked without reference to specific substances.
Ecological Effects
Work group redefined the problem to include all mining extraction
processes.
New category ranked as relatively high risk (#2 out of 6 rank
groupings).
Scale of impact - regional.
Can result in profound, generally irreversible, physical destruction
of ecosystems.
Difficult to control.
High certainty.
Welfare Effects
Ranked relatively low (#21 of 31).
Leachate and runoff kill fish and degrade surface water quality.
But most mining generally occurs in sparsely populated semi-
arid areas, which mitigates runoff.
Comments
Principal risks are ecological (making this problem similar
to #13 and #14).
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21. Accidental Releases of Toxics
Description of Problem
Toxic chemicals are accidentally released into the environment
in a variety of ways. For example, an industrial unit may
explode, emitting toxics into the air, or a railroad tank car
may turn over, spilling toxics into surface water, soil, and
roads.
Cancer Risks
Ranked in category 4 of 5 (#25 of 29).
No information is available on which to base estimates of total
potential cancer effects, but because of short duration of
exposure, cancer risk judged to be very small. Nature of
substances ranks it above oil spills. Longer-term exposure
from contaminated groundwater not considered.
Non-cancer Health Risks
Relatively high risk. High confidence in data/judgment, compared
with other problems examined.
Incidence data show substantial morbidity and mortality.
Principal populations at risk are chemical plant -and transportation
workers. Believed that chronic risks are small compared with
acute risks (most incidents counted result from fires and
explosions). Perhaps l%-4% of risks are borne by individuals
other than chemical workers.
Ranked without reference to specific substances.
Ecological Effects
Relatively medium risk (#5 out of 6 rank groupings).
Scale of impact - local.
Toxic spills, such as tank cars overturning and spilling into
streams, are perhaps more frequent than oil spills, but
volumes are typically less. Spills in small, low-order
streams can significantly damage stream ecology.
Data on incidence, exposure, and impact are limited.
Welfare Effects
Ranked relatively low (#17 of 31).
Damages to waterways and nearby property, but most releases
affect only nearby property. Damages to industry often are
the result of the accidents (e.g., fires) themselves, rather
than the toxics released.
Comments
Individual events cause certain clearly identified problems and
receive widespread attention. The public ranks this problem
as a high risk, right behind chemical waste disposal and
water pollution.
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22. Accidental Releases - Oil Spills
Description of Problem
Oil spills from offshore drilling accidents or ruptures in
storage tanks or tanker vesels can damage coastal and ocean sea
life. Some oil spills have been extremely difficult to control
and have occurred in prime fishing grounds.
Cancer Risks
Relatively very low risk (#26 of 29).
The likely cancer effects are negligible.
Non-cancer Health Risks
Not ranked.
Risks thought to be very small.
Ecological Effects
Relatively medium risk (#5 out of 6 rank groupings).
Scale of impact - local.
Oil spills can have spectacular consequences if of sufficient
magnitude, but usually they occur in areas where there is
sufficient dilution to result in only a short-term impact.
Data on overall impacts are limited.
Welfare Effects
Ranked #17 of 31.
Loss of recreational use of water areas, and danger to wildlife and
some fish species. But tangible economic damages are usually
limited, and most spills are small.
Comments
Overall, the public ranks this problem as a moderate risk.
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23. Releases from Storage Tanks
Description of Problem
Includes product and petroleum tanks that are above, on, and
underground, tanks owned by farmers, and the fuel oil tanks of
homeowners. Does not include storage of hazardous wastes in
tanks. The primary environmental hazard is contamination of
ground water. Most of the data available are on underground
storage of gasoline. There is some potential for double counting
of the risks from this problem with those from Drinking
Water (#15).
Cancer Risks
Ranked in category 3 of 5 (#20 of 29).
Preliminary analysis suggests relatively low cancer incidence
(less than one annually), but exposure modelling not as conservati^
as for some other problems.
Non-cancer Health Risk
Relatively low risk.
Risk thought to be small. Relatively few health impacts have
been reported, controls are fairly good, and people generally
avoid drinking water known to be contaminated with motor
fuel.
Ranked without reference to specific substances.
Ecological Effects
Relatively low risk (#6 out of 6 rank groupings).
Scale of impact - local.
While there are many storage tanks with hazardous chemicals, the
limited volume of releases and known ecological effects resulted
in a low ranking.
Welfare Effects
Ranked relatively low (#16 of 31).
Damage to local property from leakage. While these releases
contaminate water supplies, they are less of a problem than
releases from waste sites.
Comments
Overall, the public ranks this problem as a moderate risk.
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24. Other Ground-Water Contamination
Description of Problem
A variety of sources of pollution not counted in other
categories for this analysis also contaminate groundwater.
These include septic systems, road salt, and underground
injection wells. Some double counting with Drinking Water
(#15).
Cancer Risks
Ranked in category 3 of 5 (#21 of 29).
Data very incomplete. Assessment of one chemical in septic
systems indicates risks well under one case annually.
Non-cancer Health Risks
Not ranked.
Risks generally thought to be small. Difficult to assess
magnitude of problem involving bacteriological contamination
of private wells by septic systems.
Eological Effects
Relatively medium risk (#5 out of 6 rank groupings).
Scale of impact - local.
Large number of sources, few strict controls. Risks somewhat
diminished because ecological impact occurs only when
ground water contaminated by these sources is released to
surface waters in sufficient volume and concentration to
affect ecosystems. Soils also filter and streams dilute and
disperse pollutants, further reducing ecological risk.
Welfare Effects
Ranked as minor. Not ranked numerically.
Comments
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25. Pesticide Residues on Foods Eaten by Humans
and Wildlife
Description of Problem
Humans and other animals are directly exposed to pesticides
through residues on food. In addition, certain pesticides
bioaccumulate and contaminate food chains.
Cancer Risks
Ranked in category 1 of 5 (#3 of 29).
Cancer incidence of 6,000 annually extrapolated from seven known
oncogens to 200 potential oncogens (one-third of total pesticides
in use). Assessment does not account for so-called "inert"
materials in pesticides.
Non-cancer Health Risks
Relatively high risk. Medium confidence in data/judgment, compared
with other problems examined.
High ranking due to large populations exposed and potentially
serious health effects (e.g., acetylcholinesterase inhibition),
rather than levels of exposure, .which are often not' much
higher than levels of concern.
Ecological Effects
Work group combined this problem with #27 (other pesticide
risks). New category ranked as relatively high risk (#3 out
of 6 rank groupings).
Scale of impact - regional.
Since pesticides are designed to kill living organisms, unintended
exposure can be very destructive, both to ecosystem functions
and structures. Impacts are generally not irreversible.
Certain pesticides bioaccumulate and contaminate food chains.
Some uncertainty due to lack of data.
Welfare Effects
Ranked as minor. Not ranked numerically.
Comments
Despite many analytical uncertainties, this is clearly a relatively
high risk problem. Public attention tends to focus on individual
events and pesticides (e.g., EDB) and not on the overall problem
(which the public ranks as moderate).
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26. Application of Pesticides
Description of Problem
Risks to people applying pesticides, including farm workers
(about 10,000-250,000) or other people who mix, load, and apply
them. Major routes of exposure are inhalation and dermal
exposure.
Cancer Risks
Ranked in category 2 of 5 (#10 of 29). Individual risks can be
relatively high.
Individual risk for an applicator is usually much higher than
for the general population consuming pesticide residues on food,
but the population risk is lower because the population of
agricultural workers is small by comparison.
Total cases estimated at 100/year (estimated by a method analogous
to that used in pesticide residues on foods (#25)).
Non-cancer Health Risks
Relatively high risk. High confidence in data/judgment, compared
with other problems examined.
Modest applicator populations exposed, but potentially very
serious health effects (acute poisoning,.fetotoxicity,
teratogenicity). Exposures often far above levels of concern.
Substantial incidence estimates (e.g., 350 annual poisonings from
ethyl parathion, 100 from paraquat).
Ecological Effects
Problem not ranked because risks in this category only concern
pesticide applicators.
Welfare Effects
Ranked as minor. Not ranked numerically.
Comments
Applicators (although moderate in total numbers) can face high
risks. Public ranks problem as moderate risk.
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27. Other Pesticide Risks
Description of Problem
This problem includes leaching and runoff of pesticides and
other agricultural chemicals, and air deposition from spraying.
These chemicals contaminate ponds and affect water supplies,
and can affect cattle, farm animals, and such wild birds as
geese and ducks. Double counting with #11 (non-point sources),
#15 (drinking water), #5 (indoor air) and #30 (consumer products).
Cancer Risks
Ranked in category 2 of 5 (#12 of 29).
Ranked medium largely due to use of termiticides and widespread
consumer use of pesticides.
Non-cancer Risks
Relatively medium risk. Medium confidence in data/judgment,
compared with other problems examined.
Large populations exposed to pesticides in drinking water, very
large number exposed to pesticides in indoor air. Potential
health effects range from moderate (e.g., increased liver
weight) to serious (e.g., acetycholinesterase inhibition).
Exposures typically low relative to levels of concern.
Ecological Effects
Work group combined this problem with #25 (pesticide residues
on foods). New category ranked as relatively high risk (#3
out of 6 rank groupings).
Scale of impact - regional.
Since pesticides are designed to kill living organisms, unintended
exposure can be very destructive, both to ecosystem functions
and structures. Impacts are generally not irreversible.
Certain pesticides bioaccumulate and contaminate food chains.
Some uncertainty due to lack of data.
Welfare Effects
Ranked relatively medium (#13 of 31).
Damages to shellfish and certain fin fish from pesticide
runoff and air deposition. Many damages already accounted for
in other environmental problems (e.g., pesticides from non-
point sources, and pesticides from all sources entering
estuaries, coastal waters, and oceans). Ranking based largely
on subjective judgment.
Comments
Large populations exposed (as opposed to high doses) is reason
for "medium" ranking. Public also finds risks moderate.
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28. New Toxic Chemicals
Description of Problem
This problem area includes new chemicals introduced into commerce.
These chemicals are defined as chemicals not already listed on
the TSCA Inventory of Existing Chemical Substances. New substances
typically enter the market as substitutes for existing chemicals.
Therefore, risks considered in this environmental problem
category cover the range of risks presented by existing chemicals.
The term "new chemicals" as used here refers to "industrial
chemicals." New pesticides are considered elsewhere, and new
food additives and drugs are not considered at all in this
project.
Cancer risks
Ranked in category 2 of 5 (#15 of 29).
Extremely difficult problem to rank. The consensus is that
with the existing TSCA program the risks are moderate.
Non-cancer Health Risks
Not ranked because no satisfactory method exists for projecting
what risks will be. Risks probably low.
Ecological Effects
Not ranked. Potential effects and risks not well enough'understood.
Welfare Effects
Ranked as minor. Not ranked numerically.
Comments
Very difficult to project national impacts, as it is hard to
assess new chemicals' future uses and the risk of chemicals
not yet manufactured. Risks are reduced by the following
factors: (1) EPA's new chemicals program weeds out many
potential problems; (2) new chemicals often replace riskier
existing chemicals, thus giving net risk reduction; and (3)
most new chemicals are produced in very low volumes, have
specialty uses, and have little chance for broad exposure.
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29. Biotechnology
Description of Problem
Category includes planned and accidental releases of genetically
altered microorganisms.
Cancer Risks
Ranked in category 5 of 5 (no cancer risk identified).
Difficulty of assessing cancer risk is similar to that for new
chemicals (#28), but even less information on which to base
conclusions. No known instances of carcinogenic bioengineered
substances.
Non-cancer Health Risks
Not ranked.
No satisfactory method for projecting risks. Suspect risks
to be low.
Ecological Effects
Not ranked. Potential effects and risks not well enough understood,
Effects could be very large or small.
Welfare Effects
Ranked relatively medium (#14 of 31).
Much disagreement on how to rank this problem.
Potentially severe danger to crops, livestock, trees, marine life
accompanies introduction of new species into the environment.
U.S. agriculture is highly concentrated in only a few major
crops, increasing vulnerability.
Comments
Very difficult to assess overall risk. Public appears to rank
this as a lower risk than a number of other environmental
problems.
Generally, genetically engineered microorganisms are not expected
to survive long in conditions other than those for which they
were designed. However, there is a possibility that some of
these organisms may both survive and multiply. Given the
current system of monoculture, wherein U.S. farms specialize
in producing a small number of crop varieties, a biological
change could rapidly cause serious damage before countermeasures
could be developed. The situtation is somewhat analogous to
imported insects (e.g., gypsy moth) that have escaped and, in
the absence of predators in their natural habitats, become
major pests.
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30. Exposure to Consumer products
Description of Problem
Over 10,000 chemical substances are present in two categories
of consumer products: (1) formulations and mixtures of various
types (paints, solvents, glues, detergents, polishes, deodorizers,
etc.) and (2) in manufactured articles (clothing, housewares,
batteries, etc.). While exposure to substances in manufactured
articles is usually limited, experience has shown that potential
risks can sometimes be significant—e.g., TRIS used on pajamas,
friable asbestos in building materials, DEHP in plastic articles
that are mouthed by young children, formaldehyde emissions
from pressed wood products. Not included in this category is
exposure from substances released into the environment and
transported beyond the immediate vicinity of the user—e.g.,
contamination of drinking water or non-point source air pollution.
Where consumer products are used indoors and contaminate indoor
air, any resulting risks are likely to be double counted with
indoor air (#5).
Cancer Risks
Ranked in category 1 of 5 (tied for #4 of 29).
Risks from four substances in consumer products estimated at
100-135 cases annually. -Even though exposures generally inter-
mittent, risk believed to be high given concentrations
to which individuals are exposed.
Non-cancer Health Risks
Relatively high risk. Medium confidence in data/judgment, compared
with other problems examined.
Large populations exposed. Ambient exposures can be at levels well
above RfD's. Serious health effects possible, including teirato-
genicity and hepatotoxicity.
Ecological Effects
Not ranked. Extent of effects not adequately known.
Scale of impact - local.
Discarded plastic materials can choke fish and wildlife.
Welfare Effects
Ranked as minor. Not ranked numerically.
Comments
Clear important health risks.
Public rates this problem as lower risk than other environmental
problems.
EPA shares jurisdiction with Consumer Product Safety Commission.
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31. Worker Exposure to Chemicals
Description of Problem
Humans are exposed to numerous chemical substances in a variety
of occupational settings. These include chemical manufacturing,
chemical processing, industrial uses, and the use of chemical
substances in the trades. Because of the diverse nature of
processes and equipment and great range of physical properties
of chemicals, occupational exposure varies greatly in different
settings.
Cancer Risks
Ranked in category 1 of 5 (tied for #1 of 29). Individual risks
can be relatively high.
Large numbers of chemicals in the work place and concentrated
exposures.
High ranking due more to the consensus of the work group
than quantitative estimates. 250 cases annually from four
substances, but workers face potential exposures to over
20,000 different substances.
Non-cancer Health Risks
Relatively high risk. High confidence in data/judgment, compared
with other problems examined.
Exposed population of workers somewhat smaller than consumer
category, but still large. Work place concentrations can be
extremely high, exceeding RfD's by over three orders of
magnitude in some cases.
Ecological Effects
Not ranked because this is not an ecological problem.
Welfare Effects
Ranked as minor. Not ranked numerically.
Comments
Clearly important health risks.
Public rates this problem as moderate risk.
EPA shares jurisdiction with the Occupational Safety and Health
Administration.
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CHAPTER IV
PUBLIC PERCEPTIONS OF THE ENVIRONMENTAL PROBLEMS
How the public perceives the seriousness of different
environmental problems is very important to the setting of EPA
priorities. Measuring these perceptions was not part of the main
work of the Comparative Risk Project, but the results of a short
study done by the project staff do provide an interesting comparison
to the information developed by EPA experts as the principal
product of the project.
In order to get a better idea of how the public ranks the
problems, the project staff undertook a brief review of polling
data collected over the past two years by the Roper Organization.
Based on Roper's questions and the public's responses, the staff
developed an ordinal ranking of public concerns covering 19 of the
31 problems studied in this project.
The questions Roper asked the public do not neatly match the
31 problem areas. Only 20 of the areas are directly or indirectly
addressed by Roper. Roper frequently asked about an environmental
issue that encompassed several of the 31 problem areas. For
example, Roper's questions on chemical or toxic waste disposal
typically cover both active and inactive hazardous waste sites
(problems #16 and #17). Roper's questions on water pollution do
not distinguish between direct and indirect dischargers and
non-point sources (problems #9, #10 and #11). On the other hand,
some of Roper's questions are more detailed than the 31 categories.
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For example, Roper asked separate questions about acid rain,
industrial air pollution and auto exhaust, all of which are
components of criteria air pollutants (problem #1). As a result,
we had to apply some judgement to translate Roper's results into
as assessment of how the public ranks the 31 problem areas.
Our interpretation of Roper's results yields the ranking
of the 31 problem areas shown in the chart on the following
page. Twenty problem areas are ordinally ranked. In addition,
we put these problem areas into groupings reflecting either
generally high, medium, or low perceived risk by the public.
Our ranking was based initially on Roper questions that
ask the respondent which of nine environmental problems are
most serious. Other problem areas as.ked about in other
questions were then fit into the ranking by how they compare
to one of these original nine. Finally, some environmental
problem areas are asked about in other contexts, without
comparison to other environmental concerns. In these cases,
we placed the problem area in the ranking according to the
absolute level of public concern about it.
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Table 4-1
Summary Ranking of Environmental Problem Areas by Level of Public Concern
Public
Perception of
Risk and Ranking
Roper Area
Corresponding EPA
Environmental Problem Area
High
Moderate
Lower
1. Chemical waste disposal
2. Water pollution
3. Chemical plant accidents
4. Air pollution
5. Oil tanker spillage
6. Exposure on the job
7. Eating pesticide-sprayed food
8. Pesticides in farming
9. Drinking water
10. Indoor air pollution
11. Indoor air pollution
12. Genetic engineering
13. Strip mining
14. Non-nuclear radiation
15. The "greenhouse" effect
Ha2ardous waste sites - active (#16)
Ha2ardous waste sites - inactive (#17)
Direct point source discharges (#9)
Indirect point source discharges (#10)
Nonpoint source discharges (#11)
Accidental releases - toxics (#21)
Criteria air pollutants (#1)
Hazardous air pollutants (#2)
Accidental releases - oil spills (#22)
Worker exposure (#31)
Pesticide residues on foods (#25)
Application of pesticides (#26)
Other pesticide risks (#27)
Drinking water (#15)
Indoor air pollution (#5)
Consumer product exposure (#30)
Biotechnology (#29)
Mining waste (#20)
Radiation - other than radon (#6)
002 an<3 global warming (#8)
Note: Adequate information was not available from Roper to rank the following
EPA problem areas: Other air pollutants (#3), Radon - indoor air (#4),
Stratospheric ozone depletion (#7), Contaminated sludge (#12), Estuaries,
coastal waters, and oceans (#13), Wetlands (#14), Non-hazardous waste
sites - municipal (#18), Non-ha aardous waste sites - industrial (#19),
Releases from storage tanks (#23), Other groundwater contamination
(#24), and New toxic chemicals (#28).
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CHAPTER.V
GENERAL OBSERVATIONS AND RECOMMENDATIONS
NO PROBLEMS RANKED CONSISTENTLY "HIGH" OR "LOW" ACROSS ALL
FOUR RISK TYPES. Whether an environmental problem appears
large or not depends critically on the type of adverse
effect with which one is concerned. In many cases a problem
is ranked high on one and/or the other health risk categories
and low on ecological and welfare risk, or vice versa. This
makes the job of using these rankings to set priorities
especially tricky, and emphasizes the importance of value
j udgments.
0 Problems that received relatively high rankings in three
of the four risk types, or at least medium in all four,
*
include criteria air pollutants, stratospheric ozone
depletion and pesticide residues on food and "other"
pesticides risks.
0 Problems that ranked relatively high on health but low
on ecological or welfare effects (or by definition are
not an ecological problem) include radon, hazardous air
pollutants, indoor air pollution, drinking water,
pesticides application, and consumer and worker exposure
to chemicals.
0 Problems that ranked relatively high on ecological and
welfare effects but low/medium on health include global
warming, point and nonpoint sources of water pollution,
physical alteration of aquatic habitats (including
estuaries and wetlands), and mining waste.
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0 Problems where EPA has programs to prevent future risks
are difficult to rank on a risk basis - new toxic chemicals,
biotechnology and pesticides*
2. THE PROJECT HAS DEVELOPED A USEFUL TOOL-TO HELP SET PRIORITIES.
Despite their limitations, the data and judgments assembled
in this project are sufficiently well founded for EPA to
use in the priority setting process. As noted in the
Introduction, many factors (including laws, technology and
cost) must be considered in setting priorities. Thus,
while the results of this project are not sufficient by
themselves to determine EPA's priorities, the feasibility
of. organizing environmental protection more around the
fundamental goal of reducing risks is clear and the concept
appears compelling.
3. RISKS AND EPA's CURRENT PROGRAM PRIORITIES DO NOT ALWAYS
MATCH. In part, these differences seem to be explainable
by public opinion on the seriousness of different environmental
problems.
0 Areas of high risk/low EPA effort - radon, indoor air
pollution, stratospheric ozone depletion, global warming,
accidental releases of toxics, consumer and worker
exposures to chemicals, non-point sources of water
pollution, "other" pesticide risks.
0 Areas of medium or low risk/high EPA effort - active
(RCRA) and inactive (Superfund) hazardous waste sites,
releases from storage tanks and municipal non-hazardous
waste.
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0 The data appear to support the contention that EPA has
been more concerned about pollution that affects public
health, as opposed to protection of natural habitats
and ecosystems, in all programs except surface water
protection.
0 Problems related to ground water consistently ranked
medium or low in most respects. This may be because of
our lack of understanding of these issues. It is also
because exposure to ground water — whether of humans,
ecosystems or economic values — is significantly
limited. Other types of exposure (e.g. air, pesticides)
are simply much more direct and widespread. Groundwater
protection also raises significant issues concerning
intangible aspects of risks.
0 This divergence between risks and priorities is not
necessarily inappropriate. Not only must many factors
beside risk (legislation, technology, etc.) be considered
in setting priorities, but some problems appear to pose
relatively low risks precisely because of the high
levels of effort that have been devoted to controlling
them. It may be necessary to continue to invest in
permit processing, inspections and enforcement in order
to maintain high level of compliance.
0 in this context it is interesting to note that EPA's
priorities appear more closely aligned with public opinion
than with estimated risks. Public polls conducted
over the last two years by the Roper Organization,
indicate that the public appears to be most concerned
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with chemical waste disposal, water pollution, chemical
plant accidents and air pollution, in that order. Oil
spills, worker exposure, pesticides and drinking water are
rated as medium risks, and indoor air pollution, consumer
products, genetic engineering, radiation and global
warming are ranked as comparatively low risks.
4. STATUTORY AUTHORITIES DO NOT MATCH NEATLY WITH RISKS.
0 In two relatively high health risk areas EPA shares
jurisdiction with other agencies: consumer and worker
exposures to chemicals. Good coordination with CPSC
and OSHA is needed.
0 In some other relatively high risk areas neither EPA
nor other-Federal agencies have extensive statutory
authorities: indoor air pollution, CO2 and global warming
and non-point sources of water pollution.
5. NATIONAL RANKINGS DO NOT NECESSARILY REFLECT LOCAL SITUATIONS
LOCAL ANALYSES ARE NEEDED. This analysis is not a guide to
what may be the most serious problems in a particular area or
for particular individuals. Any attempts to set local
priorities should take into account local conditions (e.g.
presence of Superfund sites, presence of wetlands, etc.).
Indeed, more widespread use of risk as one basis for setting
environmental protection priorities would be beneficial
at all levels of government.
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6. SOME CHEMICALS SHOW UP AS MAJOR CONCERNS IN MULTIPLE
PROBLEM AREAS, notably lead, chromium, formaldehyde,
solvents and some pesticides. This suggests the need for
integrated strategies to deal with them.
7. MORE RESEARCH IS NEEDED IN SEVERAL AREAS. -The basic data
are on many subjects studied in this project are surprisingly
poor. The general weakness of exposure data is a special
problem because exposure is such an important determinant
of risk. In addition, specific data on the different types
of risks and environmental problems are often lacking.
More research would be very useful to clarify the issue of
how serious various environmental problems are, particularly
in the instances described below:
0 The best information available is for cancer risk.
Even there, however, it was not nearly as good as one
might expect.
0 The data and methods available for assessing non-cancer
health risks are poor. Exposure data are surprisingly poor,
even on chemicals that are objects of major regulatory
efforts. There is no general methodology for assessing
non-cancer risks.
0 There is no generally applicable methodology for ecological
risk assessment. The number of different types of
ecological systems, the relative scarcity of ecosystem
exposure data and methods, and scientific uncertainties
confound the problem. Moreover, the extraordinary
complexity of ecological systems prohibits objective
assessment of ecological risks.
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0 While there are generally accepted methods for assessing
welfare effects, there is a general scarcity of data
and analysis in this area. Many programs have paid
little or no attention to these effects.
0 Intangible aspects of risk play a very important part
in the way the public values environmental problems,
particularly those related to groundwater. However
we do not understand them very well and perhaps under-
estimate them.
0 The data on active and inactive hazardous waste sites,
biotechnology, and new chemicals are very poor.
0 There are two areas where the risks could be very great,
but our understanding of the problems is not very good:
global warming and stratospheric ozone depletion.
0 The overall impact of pesticides on health and ecosystems
is both large and not well understood, either by the
science community or the public.
8. EPA SHOULD NOW STUDY OTHER AREAS IMPORTANT TO SETTING
PRIORITIES. Had this exercise been conducted five, ten
or twenty years ago, the results would have been rather
different. For example:
0 only recently have some serious environmental problems
been "discovered," such as radon and other indoor air;
pollutants;
0 some problems that were once much more serious
are now much better controlled, such as direct and
indirect discharges to surface water; and
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0 some parts of the old problems are still serious, such as
some of the criteria air pollutants and certain pesticide
exposures.
Over time, as some problems are brought under better control
and as more is learned about others the relative rankings
of environmental problems described in this report are
likely to change. But this is not likely to happen quickly.
Thus, while EPA should carry out the research on specific
items mentioned above, it should now focus more effort on
the systematic study of the other factors involved in
priority setting, such as costs and feasibility of addressing
the unfinished business described in this report.
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