Occasional Papers of the East-West Environment and Policy Institute

1988

Paper No. 5

Risk Assessment of Hazardous Chemical Systems in Developing Countries Kirk R. Smith, Richard A. Carpenter, and M. Susanne Faulstich

w i t h c o n t r i b u t i o n s from

Loren Habegger, F. DeWolfe Miller, and David Weinstein

EE East-West Center

Risk Assessment of Hazardous

Chemical Systems in Developing Countries

by Kirk R. Smith,

Richard A. Carpenter, and M. Susanne Faulstich

w i t h c o n t r i b u t i o n s from

Loren Habegger, F. DeWolfe Miller,

and David Weinstein

This report is based on the workshop on "Risk Assessment of Hazardous Chemicals

in Developing Countries" held at the East-West Center,

6-24 July 1987, Honolulu, Hawaii.

East-West Environment and Policy Institute Occasional Paper No. 5

1988

© 1988 by the East -West Center A l l r i g h t s r e se rved P r i n t e d i n the U n i t e d S t a t e s o f America

CONTENTS

L i s t o f F i g u r e s and Tab le s v

Preface - i x

I n t r o d u c t i o n 1

Background o f the Workshop 3

Views from the Region 7

R i s k Assessment Process 18

The S t a t e o f the A r t i 18

An Expanded Model 22

G u i d e l i n e s 27

Hazard I d e n t i f i c a t i o n 27 Hazard Accoun t ing • 29 Envi ronmenta l Pathway E v a l u a t i o n 35 R i s k C h a r a c t e r i z a t i o n **1 In t eg ra t ed Assessment Models 54 R i s k Management 62

F i n d i n g s and Recommendations • 69 Fu tu re Trends i n the Region 69 P r i o r i t y Chemicals 70 Importance of Clean Technology 71 Needs and Recommendations 74 D i f f e r e n c e s Eas t and West:

Context and P e r s p e c t i v e 79

Appendices :

A . Databases 85 B. Case S t u d i e s 97 C. L i s t o f P a r t i c i p a n t s 125 D. Condensed Agenda 129 E . Papers Presented a t the Workshop 131

References • 133

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FIGURES AND TABLES

F i g u r e s

1. R i s k s may be ranked based on t h e i r p r o b a b i l i t y ( f requency) o f occur rence and s e v e r i t y o f the hazard 6

2. R e g i s t e r e d chemica l p l a n t s i n T h a i l a n d u s i n g and d i s p o s i n g t o x i c chemica l s 12

3. D i s t r i b u t i o n of waste volume by i n d u s t r y i n M a l a y s i a , 1985 17

4 - A . Major s t eps i n r i s k assessment and t h e i r

r e l a t i o n s h i p w i t h r i s k management 19

4 - B . R i s k assessment and management 20

5. Expanded v e r s i o n o f r i s k assessment developed d u r i n g workshop 23

6. Gene r i c m a t r i x showing s teps of hazard a c c o u n t i n g and env i ronmenta l pathway e v a l u a t i o n 25

7 -A. Flow c y c l e f o r hazardous chemica l s 31

7-B. Hazardous chemica l s move from normal f low c y c l e t o en te r env i ronmenta l pathways to human be ings and ecosystems 32

8. " P r o t o l a n d " 34

9. R e l a t i o n s h i p between q u a n t i t y , e m i s s i o n s , envi ronmenta l c o n c e n t r a t i o n s , human exposures , doses , and h e a l t h e f f e c t s 36

10-A. Event and f a u l t t r ee s a re approaches t o s c h e m a t i c a l l y b r eak ing down complex systems i n t o manageable p a r t s 37

10-B. G e n e r i c r i s k cu rves showing p r o b a b i l i t y o f f requency e s t ima tes 37

11. Comparative dose-response e x t r a p o l a t i o n s f o r a c a r c i n o g e n 44

12. D i f f e r e n c e s i n f i s h m o r t a l i t y depending on water pH and envi ronmenta l a v a i l a b i l i t y of aluminum 52

13-A. Opt imal l e v e l s o f r i s k r e d u c t i o n 68

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13-B. R e a l i s t i c a l l y , c o n t r o l o r r e d u c t i o n o f r i s k s

conies i n t e c h n o l o g i c a l packages o r s t eps 68

B - 1 . H y p o t h e t i c a l f l o w c y c l e and hazards f o r paraquat . . . 101

B - 2 . H y p o t h e t i c a l p r o b a b i l i t y o f tumors as a f u n c t i o n

of paraquat dose c o n c e n t r a t i o n 103

B - 3 . H y p o t h e t i c a l dose response curves f o r cadmium 113

B - 4 . Temporal comparison o f two h y p o t h e t i c a l c o n t r o l o p t i o n s f o r r educ ing cadmium exposure 115

B - 5 . H y p o t h e t i c a l PCB management o p t i o n s 118

T a b l e s

1. Number o f p e s t i c i d e po i son ings 13

2. E c o t o x i c o l o g i c a l v a l u a t i o n system 46

3 . C h a r a c t e r i s t i c s of s e l e c t e d s e m i q u a n t i t a t i v e h a z a r d / r i s k assessment methods 55

4 . C h a r a c t e r i s t i c s o f s e l e c t e d q u a n t i t a t i v e r i s k assessment methods 59

5. Exposure management techniques 63

6. Chemicals r e q u i r i n g p r i o r i t y a t t e n t i o n i n d e v e l o p i n g c o u n t r i e s 71

7. P o t e n t i a l f o r waste r e d u c t i o n o p p o r t u n i t i e s a c r o s s d i f f e r e n t i n d u s t r y types 72

A - 1 . Databases : A shor t l i s t 94

B - 1 . H y p o t h e t i c a l r e l e a s e s to the environment under e x i s t i n g impor t /manufac tu r ing c o n d i t i o n s and a f t e r replacement by new manufac tur ing f a c i l i t i e s . . 102

B - 2 . Doses and s tandards f o r paraquat 105

B - 3 . A l t e r n a t i v e s t o paraquat use f o r weed c o n t r o l 106

B - 4 . H y p o t h e t i c a l r i s k s from paraquat o p t i o n s 107

B - 5 . H y p o t h e t i c a l e m i s s i o n assessment u s i n g r e l a t i v e hazard index i n l i t e r s per day d i l u t i o n needed t o b r i n g r i v e r water t o s tandard 110

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B - 6 . H y p o t h e t i c a l assessment of d a i l y i n t a k e o f cadmium .112

B - 7 . H y p o t h e t i c a l h e a l t h e f f e c t s per year from cadmium exposure 114

B - 8 . Comparison among v a r i o u s h y p o t h e t i c a l c o n t r o l measures 114

B -9 . H y p o t h e t i c a l cos t e s t ima te s f o r PCB management 123

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PREFACE

The Environment and Policy I n s t i t u t e (EAPI) of the East-West Center has, since i t s establishment i n 1977, brought together students, scholars, and practitioners from the Asia-Pacific oountries and the United States to develop methods for improving management of economic growth projects that use and affect the environment. As part of this e f f o r t , the i n s t i t u t e has embarked on studies related to environmental hazards and technological r i s k s i n the developing countries of Asia and the P a c i f i c .

There i s a growing perception i n the region that toxic chemicals i n the environment pose a serious threat to human health and welfare. Thus, EAPI collaborators i n developing countries urged that i t s auspices be used to study the problem and f i n d ways i n which the multinational research s t y l e could be useful i n reaching solutions. The workshop on which t h i s report i s based was planned by EAPI s t a f f i n consultation with regional experts on tbe subject. It i s part of the longer term interest of the i n s t i t u t e i n how technological r i s k and the ways i t can be most e f f e c t i v e l y managed change during economic development.

To provide actual experiences i n hazardous chemicals management for testing the a p p l i c a b i l i t y of "Western" r i s k assessment methods, knowledgeable persons from the A s i a - P a c i f i c developing countries were Invited to meet with U.S. experts. A 3-week workshop was organized to allow information exchange as well as detailed discussions. Representatives of American consulting engineering firms that work with chemical r i s k s were invited to describe their assessment methods and mitigation techniques so that the r e a l i t i e s of commercial application might be added to consideration of theoretical concepts from research and academic professionals. Secondments of experts by Cornell University's Eoosystems Research Center, Argonne National Laboratory, and Taiwan's Energy and Mining Research and Service Organization are appreciated.

The report was compiled by a small group of participants

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serving to sort, prepare, and revise the considerable material brought to the workshop and/or written there. Substantial contributions were made by Loren Habegger, F. DeVolfe M i l l e r , and David Veinstein. The e d i t o r i a l group takes f u l l r e s p o n s i b i l i t y for the text, while g r a t e f u l l y acknowledging the pa r t i c i p a t i o n of the following:

Bruce Anderson Yeong-Ren Chen Boxing Cheng Richard C i r i l l o Joel S. Hirschhorn Maung Nay Htun Rosnani Ibarahim

H a i t i Loong Wayne Mitter David Nelson Haluk Ozkaynak Dhira Phantumvanit R.E. Soeriaatmadja John Waid

The l i s t of participants i n Appendix C shows the wealth of expertise available to us, and many ideas and comments from t h i s group are included also. We thank Mrs. Laura Miho for her pleasant and e f f i c i e n t s e c r e t a r i a l support.

E. R. S. R.A.C. M.S.F.

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INTRODUCTION

Rapid growth In the use of chemicals and chemical technology has been a characteristic of i n d u s t r i a l i z a t i o n i n developing countries. Increased a v a i l a b i l i t y of chemicals through importation and lo c a l manufacture has brought benefits to public health, food production, and other v i t a l development sectors, but experience and research, mainly i n indu s t r i a l i z e d countries, have called attention to the hazards associated with some of these chemicals. Strategies for the avoidance and mitigation of r i s k s related to these hazards should be integrated into plans for the innovation and d i f f u s i o n of chemicals and chemical technology. By doing so, we hope developing countries need not repeat the episodes of human i l l n e s s , ecosystem degradation, and costly clean-up e f f o r t s that have occurred i n Europe, North America, and Japan.

Keeping systematic inventories, performing meaningful comparisons, and undertaking effective control measures for the vast and growing array of chemicals, processes, f a c i l i t i e s , and sit e s i s a daunting Job, even with the r e l a t i v e l y great resources available i n developed countries. Plaintive and eloquent pleas have been made that quantitative and standardized techniques are needed i n order to deal adequately with the growing number and complexity of hazards (Ruckelshaus 1983)* Thus, although burdened by considerable controversy and remaining inconsistencies, various r i s k assessment techniques are being adopted by government agencies i n the United States and elsewhere to provide consistent quantitative frameworks for evaluating technological hazards and options for t h e i r control (e.g., Lave 1982; USNRC 1983; USEPA 1984b; USDHHS 1986).

In developed countries, therefore, r i s k assessment seems to offer a t t r a c t i v e advantages i n achieving rational management of hazards, although sometimes exasperating because of i t s insatiable appetite for data and intransigent tendency to hide opinion under fact. In developing countries, the si t u a t i o n i s

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somewhat diff e r e n t . In many cases, r i s k assessment may f i n d s i g n i f i c a n t hazards, both t r a d i t i o n a l and modern (e.g., pesticide runoff and poor sanitation), e x i s t i n g side by side (Smith 1987). In addition, a number of economic, technical, administrative, educational, and p o l i t i c a l barriers seem to exist i n applying modern r i s k assessment and management techniques (Covello and Frey 1987). Nevertheless, many observers feel that, despite i t s many problems, application of r i s k assessment i n i t s present form would be b e n e f i c i a l . Indeed, an e d i t o r i a l i n one of the major International environmental journals has stated:

By virtue of i t s s c i e n t i f i c nature, r i s k assessment can be used by the developing countries as e f f e c t i v e l y as i t i s increasingly used by developed nations. Risk assessment methods developed i n one country are usually applicable to other countries and the results of r i s k assessments conducted i n a developed country are applicable to developing countries with necessary modifications. However, these modifications have l i t t l e to do with the degree of development (Moghissi 1986:595).

Given the uncertainties, however, to consider these statements as a set of hypotheses worthy of test i n g would seem prudent at present. Although an increasing number of international a c t i v i t i e s are related to use of r i s k assessment methods i n developing countries (e.g., Skipper 1987; WHO/UNEP/World Bank 1987; UNCIAD 1987; World Bank 1985; WHO 1985; USNSF 1985), such hypothesis testing does not seem to have been e x p l i c i t l y and systematically performed. This paper i s the report of a workshop designed to outline how such testing might be done.

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Background of the Workshop

International collaboration can be effective i n preventing chemical damage and accomplishing the safe and selective transfer of valuable technology. These goals are shared by both the purveyors of chemicals and chemical processes and the developing countries; thus, reinforcing motivations work together to understand how r i s k assessment might help. The EAPI responded by organizing a 3-week workshop, involving 25 participants from 7 countries, e n t i t l e d "Risk Assessment of Hazardous Chemicals i n Developing Countries" (see Appendices C, D, and E).

In t h i s report, r i s k assessment i s viewed as a process—not a 1-time a c t i v i t y . The process i s c o l l e c t i n g , analyzing, and communicating s c i e n t i f i c and economic information for use by o f f i c i a l s i n policy formulation, decision-making, and r i s k management who may not be technically trained. Therefore, interpretation and transfer from the esoteric language of science are necessary. Furthermore, the timetable of economic development, not research, must be met i f r i s k assessment i s to be useful. The objeotive i s to help make better decisions i n gaining the benefits of chemicals while avoiding t h e i r hazards.

Toxic (poisonous) chemicals are the focus of t h i s report. Most chemicals are not hazardous (except i n instances of highly imaginative misuse). Radioactive chemioals have their own peculiar r i s k s , which, by comparison to many toxic chemicals, are well understood, managed, and regulated; they were not considered i n t h i s study. Pathogenic organisms i n wastes are also excluded, as are substances where the hazard i s primarily due to e r p l o s l v i t y , flammabllity, or c o r r o s i v i t y . Of course, these l a t t e r properties may contribute to the mobilization of toxic constituents and thus increase the hazard.

Although several m i l l i o n different chemical compounds are known and 60 to 70,000 have some use, only a few hundred account fo r 99 percent of the t o t a l tonnage currently manufactured. About 600 chemicals are described i n the International Register

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of Potentially Toxic Chemicals Programme (UNEP 1985). Various sources report that s t i l l fewer, perhaps 50 to 100. chemical compounds are used widely, manufactured i n large amounts, and highly toxic. Workshop participants selected an even smaller number, emphasizing the heavy metals and chlorinated organic compounds, for special concern i n their countries (see page 70, " P r i o r i t y Chemicals"),

Avoidance and reduction of r i s k by simply minimizing use of hazardous chemicals i s an important major management option. Clean technologies and substitution of less hazardous compounds appear to be p a r t i c u l a r l y effective i n managing the future growth of chemical i n d u s t r i a l i z a t i o n (OTA 1986).

Risk assessment (the determination of the importance of a r i s k ) i s a r e l a t i v e l y new term, but i t has the characteristics of an a l y t i c a l concepts that evolved from "operations research" of World War I I . Over the years, new phrases have been appended to the same approach ( i . e . , complex and dynamic sociotechnical situations can be understood and predicted through systematic description and analysis). Environmental impact assessment, systems analysis, extended benefit-cost analysis, and p r o b a b i l i s t i c r i s k assessment, for example, are related a n a l y t i c a l methods. Risk assessment can be considered an extension (by dealing with uncertainty) of an environmental impact assessment that quantifies potential hazards of economic development and technological change. Environmental impact assessment i s becoming accepted and practiced i n developing countries, and r i s k assessment as an extension should be readily assimilated into that process rather than being regarded as another new concept to be introduced with skepticism and caution. In f a c t , r i s k assessment i s being performed today i n most management situations, but I t may be i n t u i t i v e , q u a l i t a t i v e , and incomplete. We include r i s k management i n the r i s k assessment process, although we recognize the controversy over meanings of these terms (see page 18, "Risk Assessment Process").

Risk assessment i s characterized by several steps. Defined

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systems boundaries i n space and time are established. A l l assumptions are e x p l i c i t l y stated. Uncertainty i s calculated, explained, preserved i n sequential analysis, and communicated i n the f i n a l report. Risks are quantified and compared. The role of value judgment i s recognized i n the perception and acceptability of r i s k . Alternative management actions (Including no action) to mitigate each r i s k are i d e n t i f i e d and ranked using parameters such as l i v e s saved, morbidity and ecological damage avoided, cost-effectiveness, timetable for improvement, uncertainty, and acceptability by various affected groups. The need f o r , and worth of, additional research and monitoring are compared to the consequent improvement i n decision-making and the reduction of uncertainty.

Risk i s the likel i h o o d (probability) of an adverse effect, direct or i n d i r e c t , on human health and welfare. Risk i s expressed based on time or unit a c t i v i t y (e.g., worker days lost per year from i l l n e s s due to drinking contaminated water, or cancer cases per pack of cigarettes smoked). Risks are cumulative from different exposure routes (e.g., indoor and outdoor a i r p o l l u t i o n ) . Risks are usually distributed unequally over a human population or a community of organisms. Risks vary i n t h e i r l i k e l i h o o d and severity of consequences. The Bhopal-type chemical disaster was catastrophic but has occurred infrequently. Deaths from accidents during chemical transportation or warehouse f i r e s amount to several per event, but these are only occasional occurrences. Health or ecosystem effects from low-level environmental contamination may have a tenuous cause-effect relationship but also may be imposed on thousands of persons over a long time. Low frequency/high consequence r i s k s , occasional/moderate consequence r i s k s , and chronic low-level effects are a l l important for societies to evaluate and manage. Figure 1 i s one example of a simple ranking based on frequency and severity with practical interpretation of d i f f e r i n g l e v e l s of hazard and r i s k .

A description of r i s k assessment and a set of guidelines for

Potential consequences

lile/safety Mission

downtime Monetary loss

Catastrophic Death or system loss >4 months > 500,000

seve

rity

Critical Severe illness, injury, or damage.

2 weeks lo 4 months

50.000 to 500.000

Haz

ard

Marginal Minor illness, injury, or damage

1 day to 2 weeks

1,000 to 50.000

Negligible No illness, injury, or damage

<t day < 1,000

Probability of occurrence

Frequent,, repeatable

Reasonably probable, several times

Occasional, sometimes

Remote but possible

F i g u r e 1. R i s k s may be r a n k e d b ased on t h e i r p r o b a b i l i t y ( f r e q u e n c y ) o f o c c u r r e n c e and s e v e r i t y o f the h a z a r d . C a t e g o r i e s may be e s t a b l i s h e d I n a s e m i q u a n t i t a t i v e way b a s e d on c o n s e q u e n c e t o l i f e o r s a f e t y , t i m e o f i n t e r r u p t e d o p e r a t i o n s , and m o n e t a r y l o s s . The r e s u l t i s a u s e f u l , n e c e s s a r i l y f l e x i b l e s e p a r a t i o n o f r i s k s i n t o c a t e g o r i e s r a n g i n g f r o m h i g h t o a c c e p t a b l e l e v e l s o f r i s k .

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i t s performance were developed during the workshop and w i l l be explained i n l a t e r sections. To understand the context within which t h i s was done, an examination of the status of chemical hazards within the Asia-Pacific region i s important.

Views from the Region

The Asia-Pacific region i s i n a unique position to avoid many of the mistakes made by f u l l y i n d u s t r i a l i z e d countries now faced with cleaning up hazardous chemicals. However, a number of d i f f i c u l t i e s for r i s k management i n the developing countries are not being experienced, to the same degree at l e a s t , by the i n d u s t r i a l i z e d countries. Capsule summaries of the hazardous chemicals s i t u a t i o n i n selected areas are included below.

Public and governmental concern i s r e a l , but the evidence, i s anecdotal for the most part. Documentation of hazards and s t a t i s t i c s about effects has only recently been collected i n a systematic manner. A comprehensive ncradle-to-grave n approach would help policymakers set both long- and short-term p r i o r i t i e s and provide more timely information for better decisions on managing hazardous chemicals. Although the lesson to be learned from Bhopal i s important, i t should not overshadow the long-term r i s k s of continuing chemioal exposure and environmental degradation, which are not hypothetical but already exist i n carcinogens i n drinking water, indications of toxic exposure i n the blood of pesticide applicators and farmers of the region, heavy metals i n groundwater and r i v e r systems, and pesticide residues i n food.

Regulations and standards, where they exis t , tend to be piecemeal and d i f f i c u l t to enforce i n the l i g h t of limited resources and poor public understanding of the r i s k s . Oftentimes, these regulations can be met only by the larger i n d u s t r i a l f a c i l i t i e s , which must comply with worker health and safety and waste treatment controls. Throughout the region, the

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number of scattered, small-scale Industries that are ess e n t i a l l y unable to contain and handle the hazardous chemicals they use continues to grow. These "home" industries often have leaky equipment and poorly trained, workers, do not keep adequate records of their a c t i v i t i e s , are unable to meet the standards set by tbe government ( i f they are even aware of them), and dump their wastes i n the most convenient, i f i l l e g a l , way. Solutions such as small-scale hazardous waste treatment systems or centralized c o l l e c t i o n and treatment are not yet available.

Applying modern ag r i c u l t u r a l technology to the developing countries i s problematic because the costs of safer application technology and protective gear may be prohibitive. Tropical climates make wearing of protective clothing and breathing apparatus uncomfortable. Information on the dangers of pesticides i s scarce or available only i n a foreign language, and the monitoring of workers for adverse health effects i s inconsistent. Integrated pest management with i t s sophisticated application of biological controls requires a strong technical support s t a f f , which i s not usually available. Awareness of the dangers associated with pesticides, both to the environment and to humans, has improved, and many especially toxic compounds have been banned i n recent years. But the d i f f i c u l t y remains as to how to balance the need for pesticides with a s i g n i f i c a n t reduction of the r i s k s involved.

Many of the data acquired by conventional r i s k assessments are unavailable i n these countries. S t a t i s t i c a l information such as the incidence of i n d u s t r i a l accidents, public health effects, transportation patterns, and occupational exposures tends to be sketoby. The Importance of making inventories of hazardous waste sources, chemioal-handling f a c i l i t i e s , and possible s i t e s for disposal i s Just beginning to be recognized.

To give readers some idea of how the problems related to chemical technology are viewed i n the region, we have summarized the presentations given at the workshop by participants from the developing countries. (For more complete Information and

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documentation, see C i r i l l o and Fauls t ich 1988).

Operation and maintenance of imported chemical technology often cannot be performed at the designed l e v e l , sometimes because of unawareness, as wel l as lack of f inanc ia l and personnel resources. Leaks, s p i l l s , and unmanaged wastes r e su l t . Most of the countries represented at the workshop have recently established national r eg i s t r i e s of potent ia l ly toxic chemicals (KRPTCs) with the help of the United Nations Environment programme. In addi t ion to working with internat ional agencies, the region would benefit i f countries could share databases and experiences. In summary, government o f f i c i a l s and public opinion leaders appear to be receptive to advice and assistance on the hazardous chemicals problem.

The Technology Development Program of the U.S. State Department i s providing assistance to developing countries by planning studies that ident i fy hazardous waste problems and help set p r i o r i t i e s for investments to cope with them. The detai led surveys, performed by consultants i n cooperation with l oca l environmental protection o f f i c i a l s , are providing the f i r s t comprehensive and quantif ied information on chemical hazards. Countries requesting such planning assistance thus far include

.Korea, Taiwan, Malaysia, Thailand, and Indonesia.

China. A recently completed survey of China's i n d u s t r i a l a c t i v i t i e s Indicates that organochlorine compounds, organophosphates, and heavy metals such as cadmium, chromium, and mercury are among the most severe problems of an estimated 40 m i l l i o n t / y r of hazardous wastes. Hexavalent chromium po l lu t ion i s e spec ia l ly worrisome because of the number of tanneries, chromium pla t ing plants, and chromium ore processing. The use of tox ic pest icides has been r e s t r i c t ed , and safety requirements for appl ica t ion (especial ly protective clothing) and disposal of containers have been established, but pesticides s t i l l pose environmental and health hazards i n some areas.

Ear ly i n 1987, the State Council promulgated "Regulations on

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tbe Safe Management of Hazardous Chemicals'1 dealing with purchase, storage, f i r e protect ion, and safe management. Sc i ss ion standards and maximum allowable concentrations i n the working and ambient environments have also been set. To meet these standards, chemical and petrochemical plants have been equipped with incinerators and waste l i q u i d treatment processes. Tbe sludges that remain, however, are s t i l l a problem, and a more comprehensive and effect ive means of reducing chemical r i sks i s needed.

Under the leadership of the National Environmental Protection Agency and the Chinese Research Academy of Environmental Sciences, steps are being taken to es tabl i sh and implement better management of hazardous chemical systems. New techniques for the treatment and disposal of hazardous waste are under review and, as a part of the seventh 5-year plan, a ser ies of research projects i s underway. A comprehensive hazardous waste treatment and disposal f a c i l i t y that may be a prototype for China w i l l be constructed i n Shenyang c i t y . While larger factor ies are expected to handle thei r own hazardous wastes, small-scale indus t r ies , which are growing i n number, are not i n a pos i t ion to do so. To solve th i s problem, the government intends to construct treatment and disposal centers that could serve whole communities. Other projects include the evaluation and, i f appropriate, development of hazardous waste reduction technology, i nc ine ra t ion , and advanced l a n d f i l l s . A model project for chemical industry resources recovery and recyc l ing w i l l be set up i n Harbin. Data concerning the human and environmental health effects of chemicals are also being generated, and a hazardous chemicals data bank i s being established.

Indonesia. Hazardous chemical and hazardous waste management i s only i n the beginning stages i n Indonesia. At present, Individual industr ies are responsible for the treatment and disposal of the i r hazardous wastes. Oxidation ponds and other pr imi t ive types of treatment are among tbe common practices

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for l i q u i d wastes. So l id waste from indus t r i a l a c t i v i t i e s i s disposed of by means of control led or uncontrolled l a n d f i l l s , i nc ine ra t ion , and ocean dumping. L a n d f i l l s are quickly being exhausted, and new disposal s i tes are increasingly d i f f i c u l t to f i n d . Recovery and recyc l ing are also practiced to some degree.

Despite the push to i n d u s t r i a l i z e , development a c t i v i t i e s and resources continue to focus on improving ag r i cu l tu ra l y i e l d s . Consequently, the production and use of pesticides are growing. Although approximately 50 pest icides have been banned i n recent years, chemical pest control continues as one component i n a 5-part nationwide ag r i cu l tu ra l enhancement program that i s current ly underway. DDT also continues to be used i n areas where malaria poses a hazard. To reduce dependence on pes t ic ides , integrated pest management i s being encouraged.

The regulatory and technical infrastructure needed to manage hazardous chemicals e f fec t ive ly i s yet to be established i n Indonesia. A Hazardous Substances Act i s being drafted, and in ter im guidelines have been issued by the Minis t ry of State for Population and the Environment. Enforcement of ex i s t ing regulations proves d i f f i c u l t , however, espec ia l ly i n the l i gh t of l imi ted public awareness of tbe dangers of chemical exposure.

The large number and wide d i s t r i b u t i o n of a l l types of i n d u s t r i a l a c t i v i t i e s make i t d i f f i c u l t to estimate the amounts and kinds of wastes being generated. Nonetheless, an inventory of hazardous and toxic chemical wastes Is being i n i t i a t e d i n ten i n d u s t r i a l zones, which w i l l a id government agencies i n determining where the i r p r i o r i t i e s should l i e . New hazardous chemicals that are introduced are now being recorded by the Minis t ry of State for Population and the Environment, which then monitors tbe use and " l i f e - c y c l e " of the chemical. There i s an interest i n the p o s s i b i l i t y of applying low- or no-waste technologies to Indonesian industr ies , but the necessary technical information i s l ack ing .

Thailand. Thailand's hazardous chemical concerns focus on

12

Figure 2. Registered chemical plants i n Thailand using and disposing toxic chemicals (Source: Thailand Development Research Ins t i tu te 1987. Reprinted by permission of tbe publ isher) .

the growing volumes of po ten t ia l ly dangerous chemicals used i n tbe economy and the rapid ly increasing consumption of pes t ic ides . The heavy manufacturing industr ies are concentrated i n Bangkok. A survey conduoted there i n 1984 indicated that about 700 fac tor ies were generating tox ic wastes at a rate expected to double by the year 2000 (see Figure 2) .

There i s a severe shortage of information on the movement of hazardous chemicals i n Thailand. The ex i s t ing waste management systems employed by larger industr ies are frequently of poor design, are improperly administered, and lack adequate

13

Table 1. Number of pesticide poisonings

Number of Number per ag r i cu l tu ra l 100,000

Number workers a g r i . workers Year Poisoning Deaths (mi l l ion) Poisoning Deaths

1974 725 34 11.23 6.5 0.30 1975 518 18 13-27 3-9 0.14 1976 860 53 13-95 6.2 0.38 1977 1,013 32 14.92 6.8 0.21 1978 876 25 16.02 5.5 0.16 1979 1,835 18 15.02 12.2 0.12 1980 1,851 15 15.94 11.6 0.09 1981 2,159 17 17.53 12.3 0.10 1982 2,187 10 16.98 12.9 0.06 1983 2,353 17 16.68 14.1 0.10

Average 9.2 0.17

Source: Thailand Development Researoh Ins t i tu te (1987).

maintenance. Small- and medium-scale Industries lack these amenities altogether. Safety pract ices vary considerably, and accident recording and reporting are not consistent .

Pes t ic ide imports have f a l l e n s i g n i f i c a n t l y In recent years to be replaced by looa l formulation and produotion. Total consumption increased more than 20 percent from 1981 to 1984, and the pest ic ide manufacturing industry continues to expand. Consistently low leve l s of the enzyme cholinesterase ( ind ica t ing pest ic ide exposure) found i n Thai farmers indicate the health threat posed by pes t ic ides . Although pest ic ide concentrations i n the environment and food have been monitored for almost a deoade, and s t a t i s t i c s for human exposure are ava i l ab le , there i s s t i l l a need for improved controls , enforcement of l e g i s l a t i o n , and better education of the users. For example, the number and rate of poisonings i n f i e l d workers have continued to grow (Table 1) .

14

With the help of in ternat ional agencies, the National Environment Board i s preparing a comprehensive National Hazardous Waste Management Plan (NHWMP). Implementation of the NHWMP Involves a ser ies of steps beginning with the creat ion of a national inventory of hazardous wastes. Second, inter im or stop-gap measures w i l l be taken to mitigate environmental damage while the plan i s being drafted. The f i n a l plan w i l l delineate short- and long-term needs and Identify p r i o r i t y projects.

Other effor ts include decentra l izat ion of industry from Bangkok to mitigate the high r i sk to th i s community and the establishment of three hazardous waste treatment centers i n Bangkok to handle the large amounts of waste being generated.

As the controversy over the proposed tantalum plant i n Phuket i l l u s t r a t e s , public apprehension about chemicals has growing p o l i t i c a l importance i n Thailand. Thailand has become aware that public sentiment i s an important factor for consideration when making decisions affect ing public safety and welfare and that public education about chemical r i s k s i s e s sen t i a l .

Taiwan. In past decades, Taiwan industr ies exercised l i t t l e control over the generation of hazardous f l y ash, bottom residues, sludge, and metal chips resu l t ing from manufacturing processes. Hazardous materials were indiscr iminate ly dumped, buried, or improperly treated. In time, these tox ic materials began to leach, vaporize, and accumulate to s ign i f i can t concentrations i n the environment.

According to i ndus t r i a l waste surveys, annual i n d u s t r i a l wastes i n Taiwan approximate 30 m i l l i o n tons, 3 m i l l i o n of which i s hazardous. Most of the hazardous waste i s generated by the p l a s t i c s , metal f i n i s h i n g , chemicals, t e x t i l e , and e lec t ronics indus t r ies . Also , 65 small-scale pest icide manufacturing companies are operating i n Taiwan.

Leg i s l a t ion and standards se t t ing for hazardous waste treatment and disposal have been slow In coming. Although the

15

S o l i d Wastes Disposal act was put in to effect i n November 1985, detai led standards for tbe design and operation of l a n d f i l l s and incinerators are s t i l l i n tbe draft stage. Therefore, the government has only been able to enforce "temporary storage." In the absence of sat isfactory disposal methods for PCBs, for example, the government required industry to bui ld a warehouse for PCS wastes and heavy metal sludges.

The Waste Disposal Act of 1974 requires manufacturers to e f f ec t ive ly treat the waste they generate or to f ind a qua l i f i ed treatment, storage, and disposal (TSD) f a c i l i t y to dispose of t he i r wastes. Unfortunately, standards for equipment and the i r operational capab i l i ty have not yet been reviewed and c l ea r l y speoif ied . Therefore, neither the private sector nor the government has been w i l l i n g to es tabl ish a TSD f a c i l i t y . Some indust r ies are current ly mixing t he i r hazardous waste with municipal waste.

Lack of regulatory power i s also a problem. The Environmental Protection Bureau has taken an important., step i n t r a in ing qua l i f i ed inspectors and tes t ing po l lu t ion control equipment to improve the i r effectiveness. The bureau, however, i s l imi ted i n both manpower and resources to enforce ex i s t ing regulat ions .

In Taiwan the hazardous waste treatment industry i s perceived as an imported technology. Nonetheless, many small-scale-research a c t i v i t i e s are being conducted by the Indus t r ia l Technology Research Ins t i tu te , the National Science Counci l , and un ive r s i t i e s to create indigenous capab i l i ty and lead the oountry toward more effect ive treatment of hazardous wastes. These projects include hazardous waste inc ine ra t ion , s o l i d i f i c a t i o n of heavy metal sludge, and phys ica l , chemical, and b io log i ca l treatment.

Over the next 5 years, PCB wastes, heavy metal sludges, and infect ious hazardous wastes from hospi ta ls w i l l take p r i o r i t y for treatment. The recyc l ing of p l a s t i c and waste o i l w i l l a lso be of major importance. F i n a l l y , cooperation between government and

16

industry i n the research and treatment of hazardous wastes i s

desired and expected to grow.

Malaysia . Malaysia neither has the comprehensive strategy nor the f a c i l i t i e s needed to handle e f fec t ive ly the region 's hazardous chemical and hazardous waste problems. In the absence of appropriate c o l l e c t i o n , transport, treatment, and disposal f a c i l i t i e s , substantial amounts of Malaysia 's hazardous waste are being stored for future treatment ( e .g . , chromium processing sludge i s dewatered and placed i n drums). In many instances, hazardous waste i s indiscr iminate ly and i l l e g a l l y dumped at domestic l a n d f i l l s or into open sewers and waterways. A small number of commercial f a c i l i t i e s are t reat ing some toxic chemicals, but they are not able to meet the demand for the i r services .

A recent survey of more than 700 manufacturing s i t es indicates that the meta l - f in ishing industry i s the main producer of hazardous waste i n Malaysia (see Figure 3) . Other highly po l lu t ing industr ies include asbestos, p r in t ing , t e x t i l e s , re f inery , paint and dye, and electronics/semiconductors. The heavy metal and asbestos sludges and halogenated solvents generated by these industr ies are a major concern. Smaller industr ies unable to treat thei r wastes resort to dumping.

The Environmental Quality Act provides some guidelines to industry regarding proper treatment, storage, and transport of hazardous chemicals and speci f ies wastes may not be discharged into the environment except at permissible l e v e l s . Unfortunately, most of the industr ies are not able to meet these standards.

Pest icides play an important role i n ag r i cu l tu ra l production i n Peninsular Malaysia. The frequent use of these agents, however, has led to increasing resistance by target pests, r e su l t i ng i n the need for stronger dosages. Occupational and in tent ional pesticide poisonings, pa r t i cu l a r ly by paraquat, continue to Increase. Active nongovernmental organizations bring

Glass mtg plant Mtg ana/or assembly ol air conditioning unil

Blenamg ol lub oil

Others

Leather tanning/finishing prdt

Toy-making industries

Fertilizer mtg /repacking plants

Tile works

Pesticide formulation

Mineral oil recycling

Paper mills

Flexible loam mtg plant

Battery mtg

Rubber product mlg industries

Plastic product industries

Detergents/soaps/toiietnes

Resin mtg industries

Electrical appliances

Pharmaceutical prdt

Chemical plant

Motor assembly plant

Paint/ink/varmsh/lacquer mlg plant

Electronic/semiconductor

Film processing

Oil retmery

industrial gas plant

Textile industries

Foundry/metal works

Packaging and/or printing

Asbestos

Metal finishing

<0.03

t-— ' 1

2 3 Waste (<M>)

Figure 3. D i s t r i b u t ion of waste volume by i n d u s t r y i n M a l a y s i a , 1985 (Source: M a l a y s i a , Department of Environment 1985).

18

tbe adverse environmental and espec ia l ly human health impacts of pest ic ides to the a t tent ion of the publ ic . Unfortunately! the estate workers, smallholders, and r i c e farmers who come in to c losest contact with the pest icides receive l i t t l e or no t r a in ing i n the i r proper use.

Malaysia i s designing i t s f i r s t closed l a n d f i l l for hazardous wastes. To serve th i s f a c i l i t y , a c o l l e c t i o n and transportat ion system has to be established, which w i l l ensure safe transport of hazardous waste from source to disposal s i t e .

The need for an integrated approach to reduce the r i s k s associated with hazardous chemicals i s well understood i n Malaysia. A current study funded by the U.S. Trade and Development Program i s to produce a national strategy to address the problem. Progress, however, i s made d i f f i c u l t by lack of resources, unava i l ab i l i t y of basic data, and the absence of comprehensive l e g i s l a t i o n .

RISK ASSESSMENT PROCESS

Risk assessors working i n such widely divergent endeavors as banking, insurance, transport, and medical care define t he i r tasks somewhat d i f f e r en t ly , although each i s concerned with p robab i l i t i e s and consequences. Although there i s l i t t l e hope (or need) of standardized def in i t ions across such different d i s c i p l i n e s , there i s a c lear requirement to do so wi th in each so that comparisons can be made consis tent ly (Lawless 1986).

The State of the Art

While evaluating chemical and other technological hazards, i n recent years a standardized nomenclature for r i s k assessment has r i sen (Figures 4-A and B ) . In th i s framework, r i s k assessment consists of three parts, the f i r s t of which i s hazard

/

19

F i g u r e 4 -A. The major s teps In r i s k assessment and t h e i r r e l a t i o n s h i p w i t h r i s k management. There i s no s t a n d a r d i z e d v e r s i o n of t h i s d iagram, and many v e r s i o n s have been o f f e r ed (Lawless 1986) ) . T h i s f i g u r e , pub l i shed by the U . S . N a t i o n a l Research C o u n c i l (USNRC 1983), I s probably most commonly c i t e d because i t s p r i n c i p a l f ea tu re s have been adopted by the USEPA (Preuss and E h r l i o h 1987), which has i s sued d e t a i l e d g u i d e l i n e s f o r i t s a p p l i c a t i o n (USEPA 1986d). Wi th some l i b e r t y , we w i l l use F i g u r e 4-B as a su r roga te f o r a l l r e p r e s e n t a t i o n s such as t ha t i n F i g u r e 4 - A , which make a sharp d i s t i n c t i o n between assessment and management. The bas i c d i f f e r e n c e i n F i g u r e 4 - B , which i s t a k e n from Park and Snee (1984) , i s tha t the term "hazard e v a l u a t i o n " enoompasses what the USNRC d i v i d e d i n t o the separa te elements "dose-response" and "exposure assessment ."

20

Risk assessment and management

Risk

Assessment

Risk Management

Hazard identification

Hazard evaluation

Risk 1

evaluation 1

Regulatory •

response 1

F i g u r e 4 - B . R i s k assessment and management (Source : Park and Snee 1984. Repr in t ed by p e r m i s s i o n o f the p u b l i s h e r ) .

i d e n t i f i c a t i o n — t h e r e c o g n i t i o n of the e x i s t e n c e of a c o n d i t i o n

or substance w i t h the p o t e n t i a l t o cause harm. T h i s i s f o l l o w e d

by a s tep c a l l e d hazard e v a l u a t i o n i n which the degree o f harm

per u n i t c f exposure i s determined ( e . g . , the dose-response

r e l a t i o n s h i p ) . L a s t comes the r i s k e v a l u a t i o n s tep i n which the

ex ten t of exposure i s determined and the r i s k e s t i m a t e d .

The goa l of a r i s k assessment, t h e r e f o r e , i s to e s t ima te the

exoess Inoldence (over some normal or background l e v e l ) of the

adverse e f f e c t i n the p o p u l a t i o n of concern . Examples a re an

i n d i v i d u a l r i s k of cancer , an i n c i d e n c e of cancer among 1 m i l l i o n

peop le , or the m o r t a l i t y among f i s h i n an ecosystem.

Many obse rve r s f e e l tha t i t i s important to make a

d i s t i n c t i o n between r i s k assessment and r i s k management. as

d e p i c t e d i n F i g u r e s 4-A and B ) . The idea i s tha t the former

should c o n s i s t of o b j e c t i v e and q u a n t i f i a b l e d e t e r m i n a t i o n s w h i l e

21

the l a t t e r may I n v o l v e p e r c e p t u a l , c u l t u r a l , economic, p o l i t i c a l ,

and o t h e r , o f t en u n q u a n t i f i a b l e , f a c t o r s tha t w i l l a l s o p l ay a

p a r t I n management d e c i s i o n s . A proponent o f t h i s view i s the

U . S . N a t i o n a l Research C o u n c i l , which

recommend(s) t ha t r e g u l a t o r y agencies take s teps to

e s t a b l i s h and m a i n t a i n a c l e a r concep tua l d i s t i n c t i o n

between assessment o f r i s k s and c o n s i d e r a t i o n o f r i s k

management a l t e r n a t i v e s ; tha t i s , the s c i e n t i f i c

f i n d i n g s and p o l l o y Judgements embodied i n r i s k

assessments should be e x p l i c i t l y d i s t i n g u i s h e d from the

p o l i t i c a l , economic, and t e c h n i c a l c o n s i d e r a t i o n s tha t

i n f l u e n c e the de s ign and cho ice of r e g u l a t o r y

s t r a t e g i e s ( 1 9 8 3 : 7 ) .

T h i s has become the s tandard approach taken by the U . S .

Env i ronmenta l P r o t e c t i o n Agency (see Ruckelshaus 1983; Preuss and

E h r l i c h 1987).

C r i t i c s p o i n t out t h a t , i n r e a l i t y , s e v e r a l p a r t s o f the

r i s k assessment process i n v o l v e cho ices r e f l e c t i n g v a l u e

judgments to some ex ten t ( e . g . , which f a c t o r t o measure) (Raynor

and Cantor 1987). Davies notes tha t the " a n a l y t i c a l procedures

used i n a r i s k management p rocess w i l l he lp d i c t a t e the type o f

r i s k assessment tha t i s needed. [For example : ] Exposure i s a key

element i n r i s k assessment and the amount o f exposure i s

determined by r i s k management d e c i s i o n s " (1984:18) . S i m i l a r l y ,

t he S c i e n t i f i c Committee on Problems o f tbe Environment (SCOPE)

of ICSU and the World H e a l t h O r g a n i z a t i o n (WHO) emphasize tha t

r i s k assessment encompasses tbe more s c i e n t i f i c e n t e r p r i s e of

hazard i d e n t i f i c a t i o n as w e l l as the s o c i o p o l i t i c a l

c o n s i d e r a t i o n s i n h e r e n t i n r i s k e v a l u a t i o n (Krewsk i and Birkwood

1986). Even i n these broader i n t e r p r e t a t i o n s of the r i s k

assessment p roces s , however, implementa t ion o f a chosen r i s k

c o n t r o l s t r a t e g y i s des igna ted as r i s k management, d i s t i n c t from

r i s k assessment .

22

An Expanded Model

The p r e v a i l i n g d e f i n i t i o n of the r i s k assessment p rocess i s

somewhat l i m i t e d f o r the purposes fo r e seen i n d e v e l o p i n g

c o u n t r i e s ( i . e . , f o r d e c i s i o n - m a k i n g conce rn ing c o n t r o l of t o x i c

c h e m i c a l s ) . In p a r t i c u l a r , i t f a i l s to g i v e weight t o the

c r i t i c a l importance of c r e a t i n g a sy s t ema t i c d e s c r i p t i o n of the

s teps by which chemica l s move through the economy and i d e n t i f y i n g

l o c a t i o n s where hazards may e x i s t . We propose the term " f l o w

c y c l e " f o r t h i s system so as to be analogous w i t h " f u e l c y c l e "

o f t e n used i n d e s c r i b i n g energy systems.

C o n s t r u c t i n g such a f low c y c l e d e s c r i p t i o n p r i o r t o

pe r fo rming the r e s t of the assessment i s d e s i r a b l e . Indeed, i n

t h i s way p r i o r i t i e s may be e s t a b l i s h e d as t o which hazards need

to be eva lua t ed f i r s t , and l i n k a g e s l e a d i n g t o m i t i g a t i o n

measures may be uncovered. In some cases , f a i l u r e t o t h i n k

c a r e f u l l y through the system boundaries can l ead to q u i t e

m i s l e a d i n g c o n c l u s i o n s and s u b o p t l m i z a t i o n s (Smi th 1980).

I n a d d i t i o n , the procedure e n v i s i o n e d i n F i g u r e s 4-A and B

may i n f e r tha t assessment i s u s e f u l o n l y when data a re a v a i l a b l e

about exposures and dose-response r e l a t i o n s h i p s . However, u s e f u l

i n t e r i m assessments can be made even i n the absence of such

complete i n f o r m a t i o n .

As a consequence, F i g u r e 5 i s an a l t e r n a t i v e to tbe s tandard

model of r i s k assessment. F o l l o w i n g hazard i d e n t i f i c a t i o n , t h i s

v e r s i o n i n c l u d e s a s t ep we have l a b e l e d hazard a c c o u n t i n g i n

which the t e c h n o l o g i c a l system c o n t a i n i n g the hazard i s

e l a b o r a t e d and system boundaries a re e s t a b l i s h e d . T h i s may, f o r

example, e n t a i l d e s c r i b i n g each of s e v e r a l s teps i n a chemica l

f low c y c l e , i n c l u d i n g e x t r a c t i o n , p r o c e s s i n g , use, and d i s p o s a l .

In o t h e r c i r c u m s t a n c e s , however, o n l y one s tep i n the f low c y c l e

may need to be addressed . The cho ice w i l l depend on the k i n d o f

r i s k management d e c i s i o n to be made; t hus , a l i n k i s shown

between the r i s k management and hazard accoun t ing s t ages . The

23

F i g u r e 5. T h i s i s the expanded v e r s i o n o f r i s k assessment developed d u r i n g the workshop. Note the i n t i m a t e l i n k between r i s k management d e c i s i o n s and the e a r l i e r p o r t i o n s o f the r i s k assessment p roces s . Note a l s o the i d e n t i f i c a t i o n and i n s e r t i o n of a new s t e p , "hazard a c c o u n t i n g , " i n which the f low c y c l e o f tbe chemica l i s d e l i n e a t e d and system boundaries o f the assessment a re e s t a b l i s h e d . F a i l u r e to do t h i s i n a c c o r d , both w i t h the a c t u a l s i t u a t i o n on the ground and w i t h meaningful management d e c i s i o n o p t i o n s , can l ead to d i s t o r t e d and no comparable assessments .

24

c h o i c e of system boundary, t h e r e f o r e , w i l l p a r t l y depend on the

r i s k management o p t i o n s be ing con templa ted .

The next s t ep In F i g u r e 5 i s c a l l e d env i ronmenta l pathway

e v a l u a t i o n , which i n v o l v e s d e l i n e a t i n g chemica l movement from the

r e l e a s e po in t to the p o i n t of impact on humans or ecosystems

( i . e . , e m i s s i o n s , c o n c e n t r a t i o n s , exposures , and d o s e s ) . T h i s

s tage may i n v o l v e e v a l u a t i o n of each of the s t eps i n the

t e c h n o l o g i c a l f low c y c l e . Depending on da ta a v a i l a b i l i t y and

q u e s t i o n to be answered, however, i t may o n l y be necessary or

p o s s i b l e t o examine pa r t of t h i s sequence. Thus env i ronmenta l

pathway e v a l u a t i o n i n c l u d e s but i s not l i m i t e d to the hazard

e v a l u a t i o n stage r e f e r r e d to i n F i g u r e 4 - 8 . F i g u r e 6 shows the

gene ra l r e l a t i o n s h i p between hazard a c c o u n t i n g , or f low c y c l e ,

and envi ronmenta l pathway e v a l u a t i o n f o r a h y p o t h e t i c a l ca se .

The next s t e p , r i s k c h a r a c t e r i z a t i o n , i n v o l v e s l i n k i n g an

env i ronmenta l parameter w i t h human h e a l t h responses . I t i s

p r e f e r a b l e t o use dose-response i n f o r m a t i o n , bu t , i f such da ta

a re not a v a i l a b l e , l e s s d i r e c t r e l a t i o n s h i p s between

c o n c e n t r a t i o n or e m i s s i o n and response might be used, u s u a l l y by

hazard i n d i c e s .

The next stage i s r i s k management. As w i t h a l l r i s k

assessments , the a s sesso r i s o b l i g a t e d to present the r e s u l t s as

r i c h l y as p o s s i b l e ( i . e . , s t a t e d s e v e r a l d i f f e r e n t ways and w i t h

a l l u n c e r t a i n t i e s made c l e a r ) . I f the r i s k s seem unacceptab le

a f t e r an i n i t i a l e v a l u a t i o n , o p t i o n s f o r managing the s i t u a t i o n

w i l l be genera ted , i d e a l l y i n c o l l a b o r a t i o n w i t h r i s k a s s e s s o r s ,

e n g i n e e r s , and s c i e n t i s t s f a m i l i a r w i t h the prob lem. C r e a t i v i t y

i s r e q u i r e d a t t h i s po in t t o generate a v a r i e t y of c o n t r o l

o p t i o n s tha t may be aimed a t d i f f e r e n t p o i n t s w i t h i n the f low

c y c l e and pathway ( e . g . , changing the s i t e of a f a c i l i t y ,

t r a i n i n g a p p l i c a t o r s o f a p e s t i c i d e , i n t e r c e p t i n g e m i s s i o n s , or

c o u n t e r a c t i n g a dose a l r eady r e c e i v e d ) . The feedback i n d i c a t e d

by the l i n e c o n n e c t i n g r i s k management and hazard a c c o u n t i n g i n

F i g u r e 5 e x p l i c i t l y r e c o g n i z e s an impor tan t aspect o f r i s k

assessment . I t i n d i c a t e s the de s ign of the r i s k assessment w i l l

25

Hazard accounting Steps in the flow cycle

CO 3

Mining Manufac­ture

Transport Storage Use Disposal

Inventory

Emission

Concentration

Exposure

O O M

F i g u r e 6. T h i s g e n e r i c m a t r i x shows bow the s t eps o f hazard a c c o u n t i n g and envi ronmenta l pathway e v a l u a t i o n are r e l a t e d as shown i n F i g u r e 5 . Depending on the management q u e s t i o n be ing asked , the e n t i r e f low c y c l e or o n l y par t might be t aken f o r a p a r t i c u l a r r i s k assessment. Depending on the a v a i l a b i l i t y and cos t o f i n f o r m a t i o n , a l l or o n l y some of the env i ronmenta l pathways l e a d i n g from the r e l e v a n t p a r t s o f the f low c y c l e w i l l be e v a l u a t e d . See a l s o F i g u r e 9 .

depend on the type o f q u e s t i o n be ing asked and, t hus , no

u n i v e r s a l r i s k assessment method I s Independent of the use f o r

which i t w i l l be pu t . In t h i s sense , t h e r e f o r e , we argue a g a i n s t

the complete s e p a r a t i o n between assessment and management shown

i n F i g u r e s 4-A and B .

In some c i rcumstances the na ture of tbe q u e s t i o n may a l l o w

cho ice of c o n t r o l s based on comparat ive assessments of o n l y

emis s ions or exposures wi thou t go ing a l l the way to e s t ima tes o f

h e a l t h e f f e c t s . In many cases i n deve lop ing c o u n t r i e s , l a c k o f

26

data v l l l r e q u i r e tha t such t runca t ed a n a l y s i s be done.

T h i s r i s k assessment procedure i s not a once- through sys tem,

but r a t h e r an i t e r a t i v e l oop around which the r i s k a s sesso r may

t r a v e l s e v e r a l t imes . Tbe i n i t i a l c y c l e may l ead to o n l y

q u a l i t a t i v e i n d i c a t o r s of r i s k . I f , a t the management s t age ,

these i n d i c a t o r s a re inadequate t o answer the q u e s t i o n s o f

conce rn , the l oop can be r een te red a t the hazard a c c o u n t i n g s tage

w i t h a d d i t i o n a l measurements and c a l c u l a t i o n s t o ach ieve g r e a t e r

q u a n t i f i c a t i o n . Another r eason f o r c y c l i n g back through the

assessment i s t o e v a l u a t e tbe changes i n r i s k r e s u l t i n g from

v a r i o u s c o n t r o l measures be ing cons ide red a t the r i s k management

l e v e l . S t i l l another reason f o r i t e r a t i o n i s to change the

system boundar ies . An example would be to i n c l u d e o c c u p a t i o n a l

h e a l t h e f f e c t s or a t r a n s p o r t l i n k t ha t had been exc luded when

the system boundar ies were f i r s t s e t . The r e s u l t c o u l d w e l l be a

s u b s t a n t i a l s h i f t i n r e l a t i v e p r i o r i t i e s f o r c o n t r o l .

T h i s I s a f a i r use o f the term " r i s k assessment" because

even a f o r m a l l y c a l c u l a t e d e s t ima te o f i l l - h e a l t h , such as

i n d i v i d u a l cancer r i s k , i s a c t u a l l y o n l y an i n d i c a t o r of t r ue

r i s k , which i t s e l f o f t e n cannot p r a c t i c a l l y be measured. In the

same way, i n d i c e s o f h a z a r d , e m i s s i o n s , c o n c e n t r a t i o n s ,

exposures , or doses have t h e i r p lace as i n d i c a t o r s o f r i s k .

R i s k assessments of any s o r t should provide a means not o n l y

to o r g a n i z e s y s t e m a t i c a l l y q u a n t i t a t i v e i n d i c a t o r s of r i s k , but

a l s o to i n d i c a t e the degree and type of r emain ing u n c e r t a i n t i e s .

In some ca se s , t h i s can be done In a r i g o r o u s manner, but i n many

s i t u a t i o n s l a c k o f data w i l l impose the need f o r l e s s

q u a n t i t a t i v e l y s t a t e d es t imates o f u n c e r t a i n t y . Assumptions

should a l s o be c l e a r l y s t a t e d and c a r r i e d forward f o r i n c l u s i o n

i n the f i n a l r e p o r t . Too o f t e n , i m p l i c i t assumptions made by

c h o i c e s of p a r t i c u l a r system boundaries or gene r i c da ta f o r use

i n pathway e v a l u a t i o n s are never s t a t ed e x p l i c i t l y , l e a d i n g to

p o s s i b l e f a l s e e x p e c t a t i o n s by persons r e l y i n g on the r e s u l t s .

I n a d d i t i o n , as w i t h a l l s c i e n t i f i c s t u d i e s , r i s k assessments

should be sub jec t ed t o peer r ev iew and r e v i s i o n .

27

t

F o l l o w i n g the gene ra l o u t l i n e f o r r i s k assessment shown i n

F i g u r e 5, tbe next s e o t l o n p rov ides some g u i d e l i n e s f o r

conduc t i ng r i s k assessment .

GUIDELINES

T h i s s e c t i o n expands on the r i s k assessment model i n t r o d u c e d

i n " R i s k Assessment P r o c e s s , n page 18. Whi le emphas iz ing a ga i n

tha t there i s no cookbook method f o r r i s k assessment, i t w i l l be

v a l u a b l e t o d e s c r i b e i n more d e t a i l the type o f a c t i v i t i e s

performed i n each of the f i v e p a r t s of the p rocess , as summarized

i n F i g u r e 5 . These g u i d e l i n e s a re t o a s s i s t an a s sesso r i n

d e s i g n i n g a s p e c i f i c i n f o r m a t i o n g a t h e r i n g and a n a l y t i c a l p l a n to

f i t t he p a r t i c u l a r problem, t i m e t a b l e , and assessment r e sou rces

a t hand.

Hazard I d e n t i f i c a t i o n : The I n i t i a t i o n o f R i s k Assessment

An i n d u s t r y , p roces s , f a c i l i t y , p r o j e c t , or chemica l might

become i d e n t i f i e d f o r f u r t h e r assessment i n numerous ways.

• Some s o r t o f r o u t i n e a c t i v i t y ( e . g . , ongoing m o n i t o r i n g

of env i ronmenta l q u a l i t y ) c o u l d r e v e a l a h i g h

c o n c e n t r a t i o n o f a chemica l i n par t o f the environment

tha t might a d v e r s e l y a f f e c t human h e a l t h and /o r

ecosystems.

• Survey and i n v e n t o r y da ta may i d e n t i f y c u r r e n t s i t e s and

fu tu re p r o j e c t i o n s f o r hazardous wastes tha t pose

p o t e n t i a l problems.

• New s c i e n t i f i c evidence may be developed about the hazard

p o t e n t i a l o f a chemica l p r e v i o u s l y not thought t o be

hazardous .

28

• A reques t t o the government may be made f o r p e r m i s s i o n t o

manufacture or import a new c h e m i c a l .

• A new manufac tur ing p l a n t , t r a n s p o r t r o u t e , or waste

d i s p o s a l f a c i l i t y needs t o be s i t e d .

• A 5-year economic or i n d u s t r i a l development p l an c o u l d

Imply expanded use of hazardous c h e m i c a l s .

• An envi ronmenta l impact assessment of a new p r o j e c t c o u l d

I d e n t i f y chemica l haza rds .

• A chemica l s p i l l may o c c u r , c r e a t i n g q u e s t i o n s about

human h e a l t h e f f e c t s among workers or i n the community,

or damages t o b i o t a .

• S i g n i f i c a n t d e c l i n e s i n the abundance or v i g o r o f n a t u r a l

s p e c i e s c o u l d s i g n a l a problem r e l a t e d to chemica l

e m i s s i o n s .

I n these l a t t e r cases , the problem need not be f i r s t encountered

l o c a l l y or even on the same c o n t i n e n t . Chemical a c c i d e n t s a re

r e p o r t e d g l o b a l l y and can become the impetus f o r r i s k assessments

f a r from the s i t e of the a c c i d e n t .

The l i n k shown i n F i g u r e 5 between t h i s hazard

I d e n t i f i c a t i o n and r i s k management i n d i c a t e s the importance o f

c l e a r l y s t a t i n g the management problem tha t the r i s k assessment

i s expected to address and the s p e c i f i c concerns and q u e s t i o n s o f

a l l the p o t e n t i a l a c t o r s ( i . e . , government o f f i c i a l s , i n d u s t r y

r e p r e s e n t a t i v e s , and the a f f e c t e d community). The purpose o f

r i s k assessment i s t o h e l p a l l p a r t i e s make b e t t e r d e c i s i o n s

l e a d i n g t o s a f e , s u s t a i n a b l e , and s u c c e s s f u l use o f c h e m i c a l s .

P r e d i c t i o n i s the essence o f assessment. Thus, the most

gene ra l q u e s t i o n i s , "What w i l l happen i f a p a r t i c u l a r a c t i o n

( i n c l u d i n g no a c t i o n ) i s t aken?" Other p o s s i b l e q u e s t i o n s

i n c l u d e :

What type o f r i s k i s i n v o l v e d ?

How c e r t a i n i s the r i s k ?

What i s the ex t en t of the adverse e f f e c t ?

29

Where does i t come from? Who or what i s responsible? How is i t distributed among different groups? How can the risk be reduced or avoided? How much does i t cost to avoid i t ? How does i t compare to other risks, including those of alternative actions? What are the regulatory costs and social disruptions of reducing the risk?

Hazard Accounting: Defining the System

After carefully defining and stating the management problem, tbe next step is to set the proper system boundaries, expl ic i t ly stating assumptions, anticipating data-gathering problems, and assigning responsibilities. This scoping is best accomplished by convening a meeting of persons with knowledge of the chemical hazard, interest in the consequences, and s k i l l s in assessment. A scenario or outline of plausible events is an effective way of in i t ia t ing discussion that leads to designing information gathering and analysis.

At the scoping meeting, previous risk assessments of the same hazard elsewhere and of similar hazards should be sought sinoe data may be transferable to the current situation. The risk assessment f ie ld is rapidly accumulating a body of case studies and experiences that should always be used as a base for new studies, particularly by developing countries. This implies the presence of an active group of researchers/assessors who can do an effeotive literature search. Resources for such searches may not yet be available in some developing countries. International exohange of findings on speolfic chemicals and of experience with analytical techniques is accomplished through Journals, books, conferences, and v i s i t s . Substantial savings of money and time can be made by searching for previous risk assessment information before beginning new data collection. On the other hand, a different set of questions may now be

30

important, requiring new data and new analysis of tbe previously assessed situation.

Boundary setting must balance between a scope that i s so comprehensive that i t is unwieldy and Impractical, versus one so narrow as to exclude important relationships or Impacts. Geographic boundaries may be indicated by natural demarcation such as a watershed that directs the flow of waterborne hazardous chemicals, or an airshed defined by terrain and wind conditions. A time boundary may coincide with that of economic development planning (like 5 or 7 years) or be set at a specific date (like tbe year 2000) but should not be more than 20 years in the future. Data are often collected by pol i t i ca l d is t r ic ts , and these boundaries provide another way of expressing the l imits of the assessment.

The flow cycle of a chemical from "cradle to grave" w i l l essentially comprise the stages shown in Figure 7-A. Chemical engineering process descriptions and commercial distribution and use data can be the basis for a detailed and quantified flow cyole. A f i r s t approximation of waste flows can be made through the use of information on standard industrial practices. The World Health Organization's Rapid Assessment of Sources of A i r . Water, and Land Pollution (1982) and the USEPA's Emissions Handbook (1977) are examples. Figure 7-B i s a reminder that releases can occur at any point in the flow cycle, not Just as planned wastes. To what extent a l l the steps in the flow cycle are studied w i l l depend on the management question. Boundaries need not be established such that a l l steps in the cycle are included In tbe risk assessment. What is and is not included, however, should be specified.

Other l imi ts are set by assumptions that must be expl ic i t ly stated. For example, i s worker health included? Which media (air, water, soi l ) w i l l be studied? Are ecological damages to be included? Are accidents and acute exposures as well as low-level chronic contamination included? Are certain remedial or management options prohibited, such as moving a target

Raw material stage

Mining

Extraction

Petrochemical precursors

Recovery from wastes

Basic manufactur ing stage

Refining

Synthesis

Processing

Recycling

Use in processes stage

Products manufac­turing stage

Compounding Mixing Assembling

A variety ol forms and products may contain the chemical

Recycling of wastes and by-products

Uses stage

Diffuse application

Misuse

Distribution

Post-use stage

Residues

Discarded equipment

Abandoned containers

Figure 7-A. Flow c y c l e f o r hazardous chemicals. Any of the stages may i n v o l v e suboperations of packaging, storage, or t r a n s p o r t a t i o n .

Stages of the flow cycle shown in Figure 7-A

From any stage may come:

W a s t e s C o n t a m i n a n t s of:

Solids Water Liquids Materials Gases Containers Mixtures Soil

Treatment Decomposition Destruction Disposal

Releases to the environment may come from any stage to:

Atmosphere, soil, water Aquatic and terrestrial biota Food chains

Impacts on human health and welfare and on ecosystems

"Who cares and why?"

Figure 7-B. Hazardous chemicals move from the normal flow c y c l e to enter environmental pathways to human beings and ecosystems. Note the r e l a t i o n s h i p to Figure 6.

33

population? The discussions on scope should be imaginative and inventive in order to identify a l l relevant factors and events. Then the timetable for completing the risk assessment and tbe funds available w i l l l imit the f inal design to the most significant elements. Significance can be measured by the number of people involved, the geographic extent of the hazard, the i r revers ib i l i ty of health and ecosystems effects, and the frequency or duration of effects.

A materials balance w i l l help account for a l l inputs and outputs of each relevant stage in the industrial flow cycle. This entails creating a mass balance for the principal chemicals as they enter and leave the system boundary and move from stage to stage of the technological flow cycle. Depending on the management question, both routine and accidental releases may be of interest.

A map showing the location of the relevant f a c i l i t i e s , major environmental characteristics, and affected human populations and ecosystems is also useful. Figure 8 shows "Protoland," a hypothetical landscape used in the workshop to develop In i t i a l scenarios about the movement of chemicals through the economy and the environment. In specific situations, a real area map (preferably at about 1:25>000 scale) can be marked with transportation, processing, storage, use, and waste disposal symbols and arrows. The proximity of chemicals to economic, demographic, and topographic features may suggest topics for more detailed evaluation and assist in developing alternatives. The map should be placed where i t can be seen and used by everyone at the scoping meeting. It can be modified as desired during discussions and used later for communicating the assessment of the present situation and alternatives.

35

Environmental Pathway Evaluation: A Focus on Total Exposure

The prlnolpal purpose of this step in the assessment i s to obtain as good an indicator as possible of the total exposure of the target of concern (humans or specified ecosystem components) to the chemical(s) of interest. Figure 9 sketches the gross categories or steps in the pathway leading from hazard to exposure. Some idea of the inventory of chemical hazards is achieved during the hazard accounting stage just described. The degree to which this inventory can be expected to be released depends on information about both routine emissions and accidental releases.

In recent years, an increasingly sophisticated body of knowledge entitled probabilistic risk analysis (PRA) has been applied to the problem of estimating accident frequencies and consequences for complicated f ac i l i t i e s such as chemical plants. These techniques can be used to estimate the risks of low probability/high consequence events even when no such accident sequences have yet occurred in the systems of interest. This i s done by conceptually breaking down a l l identified accident scenarios into small enough subsystems such that failure data are available for each. In some cases, this may mean going down to the level of individual valves, pipes, and switches. This task can best be accomplished by a group that includes not only engineers and risk analysts but also active participation of operators familiar with the plant in question or similar plants.

One such procedure, f i r s t developed in Europe, i s termed a HAZOP (hazard and operability) study (American Institute of Chemical Engineers 1987). Such an effort can be valuable by i t se l f in identifying problem areas in a f a c i l i t y , in addition to being the f i r s t step of a PRA. For a PRA, these scenarios are then linked by means of, sometimes elaborate, event trees and fault trees as demonstrated in Figure 10-A. Each accident scenario corresponds to a pathway through such constructs.

Inventory •Emissions Concentration- Exposure Health effects

An inventory specifies the lype and folal amount of a hazardous chemical at a specific location and describes the condition of the containers and the storage facility.

Emission of pollutants occurs when a chemical is released to the environment. Such a release may be accidental or purposeful.

The concentration of pollutants not only depends on the emissions but also on the environmental conditions (e.g., ventilation conditions inside a building if the concern is indoor pollution).

Exposure depends on how many people breathe, ingest, or come Into skin contact with what concentration for how long.

Dose measures how much pollutant is actually in the body and depends not only on exposure but also on factors such as the rate of breathing and the size ol the particles.

Health effects depend not only on dose but also on such factors as age. sex, whether the person smokes, and the existence of other diseases.

Figure 9. This f i g u r e shows the r e l a t i o n s h i p between q u a n t i t y , emissions, environmental c o n c e n t r a t i o n s , human exposures, doses, and h e a l t h e f f e c t s — w h a t i s c a l l e d an environmental pathway by the workshop. At each step, d i f f e r e n t u n i t s and techniques of measurement are used with d i f f e r i n g degrees of r e l i a b i l i t y and s p e c i f i c i t y . A complete understanding of the r i s k represented by a p o l l u t a n t and the p o t e n t i a l ways to manage i t would e n t a i l e x p l o r i n g a l l the l i n k s shown. In p r a c t i c e , l a c k of data, time, or money s u b s t a n t i a l l y l i m i t s most pathway e v a l u a t i o n s .

37

O R Pump

seal fails

Emergency! isolation valves fail to close

Release of

lammable chemical

§nition ccurs

Rapid ignition

Delayed ignition

Fire

Explosion

No ignition Vapor disperses

Analysis of causes _ | Analysis of consequences _

(Fault tree) I (Event tree)

Figure 10-A. Event and fault trees are approaches to schematically breaking down complex systems into manageable parts for which failure rates or other risk-related data can be found. It i s thus possible to construct some Idea of the failure rate and resultant risk of a large, complex, and new entity, such as a chemical plant, even i f no data about i t s performance exist. This example shows the differences between the two approaches and also how they can be used in a complementary manner.

log scale

log scale

Figure 10-B. Generic risk curves showing probability of frequency estimates. This set of curves can be interpreted as follows: there is a 10$ chance that the frequency of an event with consequence X is less than ; a 50$ chance that i t i s less than $ ; and a 90S chance that i t i s less than

38

In this approach, the risk analysis i s oriented toward answering three questions: What can happen? (scenarios); How l ike ly i s i t to happen? (frequencies); and If i t does happen, what i s the outcome? (consequences) (Kaplan and Garrick 1981). A l l of these can be linked through event and fault trees such that the risks represented by each of tbe scenarios can be totaled. In addition, i t i s mathematically possible to maintain a distinction between frequency and probability such that the probabilistic distribution of risk is maintained throughout the analysis (Figure 10-B), Use of Bayesian probability theory allows the incorporation of uncertainty due to both measurement variation and expert judgment (Kaplan 1985). Extensively used in studies of nuclear power plants, PRA has not yet been applied to many chemical f a c i l i t i e s . Although in some ways more di f f icul t to oreate (e.g., many fac i l i t i e s do not have current plant schematics), chemical process industry (CPI) PRAs show promise as a risk management tool. (For an easily accessible and concise description of CPI PRA, see Kazarians and Boykin 1986; for a more detailed evaluation, see Boykin and Kazarians 1987). In many developing country situations, however, such PRAs would have to be carefully tailored to be appropriate to the l imits of data and analysis resources.

Emissions determined by PRA or historical site-specific data and generic Information about similar plants elsewhere can be combined with meteorological, hydrologlcal, and geographic information to estimate environmental concentrations. Alternately, environmental measurements may be available that refleot total emissions over time. Given information about population distributions, human exposures can be estimated as wel l .

Although ideally a direct measure of exposures or doses would be available, in many cases measurements w i l l be restricted to previous pathway steps. In these cases, two choices are available. Either data at these previous steps can be used as an indicator of relative hazard, or mathematical models can be used

39

to estimate exposures from the limited specific data and some general information about how this particular chemical moves in the environment. There may be considerable uncertainty in both measurements or predictions of the often complicated pattern of environmental concentrations and exposures that can result from even a relatively simple and well-understood pattern of emissions. (Tbe section on "Integrated Assessment Models," page 54, summarizes the characteristics of a few hazard indices models.)

The emphasis on total exposure means focusing on the chemicals as they appear in a l l media that directly affect the target organisms. In humans, the amount of chemicals breathed and the food and water consumed are of most interest, and not so much the concentrations elsewhere in the environment. Although this may seem obvious, ambient levels have been used Instead in many exposure studies. The routes by which humans become exposed to hazardous chemicals depend only in part on the distribution and transport of the chemical in the environment. Some chemicals have multiple routes of exposure. Identifying and quantifying each one is Important, but many w i l l have their effect through only one or two of the following principal routes: dermal (skin), lungs by inhalation, gastrointestinal tract by ingestion, and placental (from mother to fetus).

As Figure 9 shows, a determination of dose rather than exposure might result in an indicator closer to the measure of most interest ( i . e . , health effect). For exposure to be translated to dose, the chemical in question has to be absorbed by the body. Depending on the species of chemical and the route of exposure, absorption may be high or low. Approximately 95 percent of elemental mercury vapor inhaled i s absorbed by the lungs, but only about 1 peroent ingested w i l l be absorbed by the gastrointestinal tract, for example. Combined with data on ventilation rates, water consumption and food consumption rates, and the specific absorption rates, an estimate can be made of what might be termed "nominal" dose. Finally, for verification,

40

an association could be established between the nominal dose and an appropriate measure of body burden (retention) of the chemical.

Direct dose assessment requires that the chemical! a specific metabolite, or specific biologic marker be measured in tbe appropriate body fluid or tissue. Organochlorines such as PCBs are a good example. In areas where the PCB content of f ish i s high, there is a strong association between the number of fish eaten, as determined by dietary history, and the level of PCBs in human body fat or milk. Negligible amounts of PCBs are found in the water i t se l f .

There are s t i l l limitations in the interpretation of exposure depending on the chemical and the tissue or f lu id measured. A classic example is the level of lead in the blood by which the exposure status of any individual is readily established. Blood lead levels, however, represent only current exposure. The long-term exposure to lead, on the other hand, can be determined by i t s deposition in teeth.

Despite the attraction of dose as an indicator, practical considerations often make di f f icul t i t s determination by either measurement or modeling. Measurement of exposure can sometimes be done based on direct measurement of the concentrations of chemicals in the a i r , water, and food actually consumed. In many oases, however, indirect exposure assessment must often be relied upon because of cost. This involves coupling a knowledge of the concentrations of the chemical in various locations with a knowledge of the characteristics of the individual or population under consideration (Lioy 1987). Examples of characteristics that might be correlated with exposure are age, sex, ethnic origin, oooupation, residence, a history of exposure as determinded by interview, and other relevant socioeconomic factors. Indirect exposure assessment complements and strengthens direct exposure assessment (USNRC 1985). Indirect exposure assessment alone is limited because the assessment i s not specific for the exposure in question, and also by observer

41

bias and recal l bias. These limitations can be minimized by establishing a gradient where different groups of individuals are ranked depending on the extent of exposure. For example, the closer an individual resides to the source of the exposure, the higher the probability of exposure. Therefore, in some circumstances, distance from tbe source may be a reliable indicator of exposure and r isk.

The reader should bear in mind that exposure assessment does not establish the dose of a toxic chemical that any given individual has received. Estimating dose is d i f f icu l t i f the exposure occurs only once and during a very short time. It is also almost impossible to estimate a dose received by the body and more specifically by the target tissues or organs when the exposure occurs over a long time, and the concentration of the toxic chemical in the a i r , water, and food varies considerably. To summarize, although obtaining dose data is the most accurate approach for evaluating risk and should be undertaken i f possible, in most cases exposure (usually indirectly determined but sometimes directly measured) w i l l be the indicator of choice.

Risk Characterization

Although this seotion is divided into two parts, the f i r s t dealing with human health and the second with ecosystem impacts, a number of issues relate to both. Principal among these i s the importance of reporting results in consistent and comparable as well as accurate ways. Some indication of uncertainty is advisable, for example, but should be stated clearly. Uncertainties should not be hidden by solely using 50 percent, 95 peroent, or any other confidence Interval by i t se l f . A distribution should be reported i f at a l l possible or, at the least, appropriate techniques, such as Monte Carlo, should be applied to determine accurate overall confidence levels rather than what Is often done, which is to multiply, for example, the

42

95 peroent level for each step. This results in mathematically incorrect estimates that are inconsistently conservative. (See, for example, DSEPA 1986d.)

Human Health. Basically two approaches are used to ascertain the health impacts of toxic chemicals. The f i r s t relies on extrapolation from laboratory tests, such as controlled exposures to animals. The second approach applies epidemio­logical investigation to human populations.

Dose-response extrapolation. How do we determine how much of a chemical exposure is necessary to result in an adverse health effect in an individual? Conversely, how do we know i f there is a safe dose at which no adverse effects w i l l be seen over a lifetime of exposure?

For many chemicals toxic to humans, no data are available for dose-response in humans; thus, tests conducted on animals must be used Instead. In most cases, humans w i l l be exposed to high doses that result in acute effects only from accidents and not from exposure for long periods.

Whether the data are of human or animal origin, there is extreme biologic variation in the response at increasingly lower doses such as may actually be encountered in the environment. In order to detect reliably an increase of 1 cancer per 10,000 animals, many hundred thousands of test animals would have to receive the same low dose and be followed for their lifetimes. Because of this impracticality, at low doses, the frequency of health effects can only be estimated from studies conducted at high doses. Even so, relative to the number of potentially toxic ohemioals, few chemicals have been fully tested under rigorous conditions.

A number of methods (mathematical models) are available for extrapolating from high doses to estimate the frequency of effects at very low doses. The data for a given chemical that has been tested on animals are used to f i t a mathematical model,

43

using regression techniques. That i s , for each dose the total number of animals treated i s divided into the number of animals that showed an effect (e.g., developed a tumor). This fraction, frequency, or probability of response for each dose comprises the raw data for the model.

One of numerous models can be chosen to translate these data to risk estimate at low doses (e.g., linear, quadratic, logi t , Veibull , one-hit, multihlt) . Each model is based on certain biochemical and physiological assumptions and has advantages and disadvantages. No one method has been shown to be better than another; often, they a l l show a good f i t to the experimental data available for different chemicals at the higher doses. Unfortunately, at low doses these different models predict very different response frequencies. Differences can be as great as 4 or 5 orders of magnitude (see Figure 11). The linear model consistently predicts the highest response frequency per unit dose in the very low dose range and therefore is usually the most conservative. The linear model i s the least l i ke ly to underestimate the human health risk and i s recommended by most regulating agencies for known or suspected human carcinogens. For noncarclnogena, the quadratic model that predicts a threshold dose, a dose at which there i s no effect, i s often used.

By using these models, a prediction can be made as to how many additional negative health effects (e.g., excess cases of cancer) w i l l occur, given various low doses of exposure to humans over a lifetime, for a specific chemical. The following example briefly i l lustrates this process:

A known carcinogen is discovered in the drinking water supply, and a search is made of the literature to find the potency of this carcinogen ( i . e . , the frequency of cancers observed in animal tests—assuming no human data—at various high doses). These data are used in a linear regression model to f i t a line and extrapolate to lower doses similar to the drinking water concentration. We assume that people

44

Dose-response Low-dose extrapolation

Figure 11. Comparative dose-response extrapolations for a carcinogen: M, multistage model; W, Weibull model; L, logit model; G, gamma multihit model; P, probit model. Note how models that f i t tbe data equally well at high doses can produce very different results when extrapolated to low doses (Adapted from Covello and Herkhofer 1987:255).

drink 2 l i t e r s of water per day for 70 years (lifetime). In terms of equivalent mg of chemical per kg of animal body weight per day for the lifetime exposure of the animal, we find that 2 animals out of 10,000 could be expected to develop the cancer (also assuming 0 additional cancers in the control animals). The estimate of risk for human beings i s thus 2 x 10~̂ excess cancers over a lifetime of exposure.

In this example, we assume that the linear model accurately extrapolates to lower dose responses and that there are no differences between animal and human responses to this carcinogen. We used mg/kg/day to relate animal size to

45

human size but could have used mg/m body surface/day instead, with very different results. We did not consider the effect of other exposures that could either reduce or increase the response to this carcinogen.

The reader must bear in mind that estimating dose-response relationships Is a complex task. Only some of the basics have been addressed here. (For more detailed information on methodology, see Rowe 1983; Ricci 1985; Hallenbeck and Cunningham 1986; Covello and Merkhofer 1967; Sielken 1967, for example.)

Epidemiological evidence. The demonstration of human health effects ultimately determines whether or not the chemical in question is a hazard. Moreover, the chemical can be hazardous at high doses, but the effects at lower doses may not be known. It has been well known for more than a century, for example, that lead at very high concentrations in the food, water, or a i r causes a variety of adverse human health effects. As better epidemiologic studies were designed and completed, the effects of lower concentrations of lead have become known and, correspondingly, the standards for l imiting lead exposure have been made more stringent.

Chemicals can cause a variety of health effects, some of which are specific to the respective chemical while others are not. Nonspecific health effeots and those that occur only after a long latent period of exposure are particularly dif f icul t to attribute to a specific ohemical.

Some of the approaches for determining the direct impact of a hazardous chemical on human health are lung function tests for airborne chemicals; biologic markers in the blood (such as chromosome breakage), urine, or stool; DNA adducts of the chemical in the blood or urine; reproductive disorders such as birth defects; morbidity, cancer surveillance; mortality, cancer registry; and neurologic outcomes such as dementia or neuromotor dysfunction.

46

Epidemiology, the study of the distribution and determinants of disease in the human population, has a limited number of approaches or study designs by which exposures to chemicals can be shown to cause, or be associated with, health effects.

• Eoologlc studies: Distributions of the exposure to a toxic chemical and distributions of disease are f i r s t examined independent of each other. A correlation is made between the occurrence of exposure and disease in each community, town, d i s t r i c t , or defined population unit (usually made on a geographic basis). Advantage: Usually can be done with existing data collected on environmental samples of the chemical and surveillance data collected separately by health authorities; inexpensive and quick. Disadvantage: Weak study design subject to error.

• Case control studies: Individuals with disease (cases) and individuals without disease (controls) are systematically recruited, usually at a health f a c i l i t y . The frequency of exposure is determined in cases and controls, most often by interview. Stat is t ical tests are conducted to determine i f the frequency of exposure i s actually greater in the cases than in the controls. Advantage: Moderate cost, good for diseases (effects) that are infrequent and/or have long latency periods ( i . e . , cancer). Disadvantage: Subject to sampling errors, unable to determine magnitude of health problem in tbe population.

• Cross-sectional studies: A population is defined, and a sample of the population is made. Each individual in the sample is examined for exposure and health effects. Advantage: Can determine the distribution and magnitude of health effects problem in the population at r isk. Disadvantage: Can be very expensive, individuals may not

47

agree to participate in tbe study, not good for rare diseases.

• Prospective studies: Groups of individuals, exposed and not exposed, are identified. Both groups at the start of the study are free of the disease in question. Both groups receive follow-up examinations for a given period, which i s usually sufficient for tbe disease to occur naturally in the nonexposed group. Occurrence of disease in the exposed is compared with the nonexposed. Advantage: This design is the best for establishing a causal relationship between the exposure and the health effect. Dlsdavantage: Expensive; not good for long, latent diseases or rare diseases; infrequently used in environmental epidemiology.

Epidemiologic methods can also be used to identify health effects due to hazardous chemical exposures after they have occurred, but before the relationship between tbe hazard and the health effect i s established. The best-known example of this i s when a disease occurs at a significantly higher rate than expected in a population, and a chemical exposure Is suspected to have been the cause. This i s often referred to as a cluster of disease and can be identified by epidemiologic surveillance methods. For example, the unusually high occurrence of a rare cancer, angiosarcoma of the l ive r , was noted among certain occupational groups. A very strong association was found between this cancer and exposure to vinyl chloride monomer. This approach can be used in the community as well as among occupational groups. (See Crump and Allen 1987 for more discussion of using epidemiological data for quantitative risk estimation.)

Ecosystem Evidence. Ecosystems provide direct support for human populations as well as sustaining other species upon which society depends. Processes within each ecosystem generate and

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Table 2. Ecotoxieological valuation system

Element Parameter

Degradation capacity Soil conditions and climate

Dilution capacity Pathways, scale, and seasonality of water flow

Types of disturbance Scale and frequency of flood, drought, climate, and agricultural cycles

Key regulator species Life-cycle characteristics of economic species (predators, parasites, so i l microflora, f ish, shrimp, fish food organisms, etc.)

Special features Importance for protected species and migratory species

Souroe: Adapted from Koeman (1982).

transfer energy and nutrients necessary for populations to survive. Any pollutant that impairs the functions supporting these resources w i l l affect ecosystem populations and, in turn, humans. Although ecosystems deserve protection even when the species are of l i t t l e consequence to human populations, in this report our primary concern is with negative human health effects from toxic chemicals released into the environment. Table 2 l i s t s parameters that might be used to characterize ecological regions for an ecotoxlcological valuation system. For a prediction of effeots, the basic ecotoxlcological data should be evaluated in view of regional ecological parameters. Here, however, we focus only on the means to evaluate the ecosystem-mediated pathways by which a chemical might directly affect human health and also on the loss of welfare derived from harvesting other species damaged by chemical contamination.

For example, a pesticide may have an unexpected toxic effect upon a major predator of the target pest. Pesticide use could result in an eventual increase in abundance of the pest, leading

49

t o a d e t r i m e n t a l e c o n o m i c e f f e c t u p o n t h e human p o p u l a t i o n

d e p e n d i n g o n t h i s c r o p , and p o s s i b l y a d e c r e a s e i n t h e h e a l t h o f

p e o p l e who depend o n t h e c r o p a s a f o o d s o u r c e . A s a s e c o n d

e x a m p l e , c o n s i d e r t h e c a s e i n w h i c h a t o x i c a n t i s r e l e a s e d i n t o

t h e e n v i r o n m e n t i n d i f f u s e l o w c o n c e n t r a t i o n s , b u t i s a c c u m u l a t e d

t o h i g h e r c o n c e n t r a t i o n s t h r o u g h t h e f o o d c h a i n . Humans who e a t

a n i m a l s h i g h e r i n t h e f o o d c h a i n may be e x p o s e d t o c o n c e n t r a t i o n s

g r e a t l y i n e x c e s s o f wha t was a n t i c i p a t e d f r o m t h e r e l e a s e d

q u a n t i t i e s . T h i s s e c t i o n d i s c u s s e s s u c h m o d i f i c a t i o n s o f t h e

e x p e c t e d i m p a c t o f t o x i c s by e c o s y s t e m f u n c t i o n i n g . ( S e e Conway

1982 f o r a more d e t a i l e d d i s c u s s i o n . )

T h e r e i s a m u l t i t u d e o f p o t e n t i a l w a y s a n e c o s y s t e m c o u l d be

a f f e c t e d by a c h e m i c a l o r i n w h i c h t h e p a t h w a y o f a c h e m i c a l t o

human e x p o s u r e c a n be m o d i f i e d . S i n c e e c o s y s t e m r e s p o n s e t o

c h e m i c a l s mus t be i n i t i a t e d by t h e i n t e r a c t i o n o f a t o x i c a n t w i t h

some o r g a n i s m , e v a l u a t i o n s s t a r t w i t h l a b o r a t o r y s t u d i e s i n w h i c h

s i n g l e o r g a n i s m s a r e d i r e c t l y e x p o s e d t o t h e t o x i c a n t I n t h e

a b s e n c e o f o t h e r o r g a n i s m s o r a b i o t i c c h a r a c t e r i s t i c s o f t h e i r

n a t u r a l e c o s y s t e m s ( P e a k a l l e t a l . 1 9 8 5 ) . A c o m m u n i t y o f many

o r g a n i s m s , h o w e v e r , may r e s p o n d q u i t e d i f f e r e n t l y f r o m e a c h

o r g a n i s m i n d i v i d u a l l y . F u r t h e r , t h e p h y s i c a l e n v i r o n m e n t and t h e

manne r i n w h i c h t h e o r g a n i s m i n t e r a c t s w i t h t h a t e n v i r o n m e n t c a n

g r e a t l y c h a n g e t h e r e s p o n s e t o a g i v e n l e v e l o f c h e m i c a l

p o l l u t a n t . T h e e c o s y s t e m c a n m o d i f y t h e f o r m and t r a n s p o r t o f a

t o x i c c h e m i c a l . O r g a n i s m s may be b u f f e r e d ( s h e l t e r e d ) f r o m

e x p o s u r e , w h i l e i n o t h e r c a s e s e x p o s u r e i s g r e a t e r t h a n e x p e c t e d .

F i v e l e v e l s o f t e s t s may be c o n d u c t e d t o m e a s u r e b i o l o g i c a l

r e s p o n s e t o c h e m i c a l s . A t l e v e l 1, f o r w h i c h mos t i n f o r m a t i o n i s

a v a i l a b l e , s i n g l e s p e c i e s t e s t s a r e c o n d u c t e d . L e v e l 5 i n v o l v e s

f i e l d e x p e r i m e n t s o n w h o l e e c o s y s t e m s , w h i c h h a v e r a r e l y b e e n

made ( P e a k a l l e t a l . 1 9 8 5 ) . L e v e l 1 t e s t s a r e r o u t i n e l y

c o n d u c t e d f o r m o s t c h e m i c a l s d u r i n g p r e m a r k e t s c r e e n i n g . They

i n v o l v e s h o r t - t e r m e x p o s u r e s and some g r o w t h and r e p r o d u c t i v e

s t u d i e s o n a few r e p r e s e n t a t i v e m i c r o o r g a n i s m s and

m l c r o i n v e r t e b r a t e s . I n f o r m a t i o n o n t h e s e t e s t s I s r e a d i l y

50

a v a i l a b l e . L e v e l 2 t e s t s i n v o l v e ( 1 ) l i m i t e d s c r e e n i n g f o r

s p e o i e s l i k e l y t o be m o s t s e n s i t i v e t o t b e c h e m i c a l , ( 2 )

e v a l u a t i o n o f t h e s e n s i t i v i t y o f s p e c i e s p l a y i n g a c r i t i c a l r o l e

i n t h e f o o d o h a i n o r n u t r i e n t r e c y c l i n g i n t h e e c o s y s t e m , a n d ( 3 )

a s s e s s m e n t o f t h e i m p a c t o n k e y e c o s y s t e m p r o c e s s e s s u c h a s

p h o t o s y n t h e s i s a n d d e c o m p o s i t i o n r a t e s . Though some i n f o r m a t i o n

i d e n t i f y i n g t o x i c i t y t h r e s h o l d l e v e l s f o r s e n s i t i v e s p e c i e s i s

a v a i l a b l e , t h e i m p o r t a n c e o f t h e s e o t h e r e v a l u a t i o n s has o n l y

r e c e n t l y been a c k n o w l e d g e d . T e s t s a t l e v e l 3 e v a l u a t e t h e

c u m u l a t i v e e f f e c t s o f s e v e r a l c h e m i c a l s . T e s t s a t l e v e l 4 u s e

m i o r o c o a m s ( l a b o r a t o r y r e p l i c a s o f e c o s y s t e m s ) t o e v a l u a t e

m u l t l s p e c i e s i n t e r a c t i o n s and s p e c i e s i n t e r a c t i o n s w i t h a b i o t i c

c o m p o n e n t s o f t h e e c o s y s t e m s . L e v e l 5 t e s t s u s e l a r g e - s c a l e

f i e l d e x p e r i m e n t s f o r c o m p l e t e e c o s y s t e m r e s p o n s e .

S i n c e t i m e and f u n d s a r e o f t e n n o t a v a i l a b l e f o r t h e s e t e s t s

i n a d e v e l o p i n g c o u n t r y , t r a n s f e r o r e x t r a p o l a t i o n f r o m r e s u l t s

o b t a i n e d i n o t h e r o o u n t r i e s i s a c c e p t a b l e a s a n i n t e r i m m e a s u r e

f o r m a k i n g r i s k e v a l u a t i o n s . S h o r t - t e r m , d i r e c t d o s e - r e s p o n s e

d a t a f o r s i n g l e s p e c i e s a r e a v a i l a b l e f o r many c h e m i c a l s f r o m t h e

O r g a n i z a t i o n f o r E c o n o m i c C o o p e r a t i o n and D e v e l o p m e n t ( 1 9 8 0 )

p r e m a r k e t t e s t s . The p r e m a r k e t t e s t s y s t e m c o m p r i s e s a 9 6 - h o u r

a l g a l g r o w t h t e s t , a 2 4 - h o u r i m m o b i l i z a t i o n t e s t , r e p r o d u c t i v e

t e s t s o n D a p h n i a s p p . f a 9 6 - h o u r a c u t e t o x i c i t y ( L C ^ Q ) t e s t f o r

f i s h , and a n a c u t e ( L D , - 0 ) end 1 4 - t o 2 8 - h o u r r e p e a t e d d o s e o r a l

t o x i c i t y t e s t o n r a t s . T h e s e t e s t s p r o v i d e two c r i t i c a l p i e c e s

o f i n f o r m a t i o n : t h e t h r e s h o l d c o n c e n t r a t i o n o f t h e c h e m i c a l b e l o w

w h i c h a s p e c i e s shows no m o r t a l i t y r e s p o n s e , and t h e m e d i a n

l e t h a l c o n c e n t r a t i o n ( L C ^ Q ) a t w h i c h 50 p e r c e n t o f t h e e x p o s e d

o r g a n i s m s d i e . S u c h t e s t s do n o t , h o w e v e r , a c c o u n t f o r c h r o n i c

o r d e l a y e d e f f e o t s . I n f o r m a t i o n a v a i l a b l e f r o m t h e USEPA

c o n c e r n i n g l e t h a l c o n c e n t r a t i o n s o f p e s t i c i d e s i s s u m m a r i z e d by

J o h n s o n and F i n l e y ( 1 9 8 0 ) . We mus t r e e m p h a s i z e t h a t s u c h t e s t s

e v a l u a t e t h e r e s p o n s e o f s p e c i e s i n l a b o r a t o r i e s and t h u s o n l y

g i v e a g e n e r a l i n d i c a t i o n o f t h e c h e m i c a l ' s i m p a c t .

T h e s e r e a d i l y a v a i l a b l e d a t a f r o m t e s t s o f s p e c i e s

51

t o l e r a n c e s ( L D g g and L C ^ Q ) F a l o n g w i t h a t h o r o u g h s u r v e y o f

s p e c i e s p r e s e n t I n t h e e n v i r o n m e n t s l i k e l y t o be e x p o s e d t o a

c h e m i c a l , c a n p r o v i d e s u f f i c i e n t i n f o r m a t i o n t o e v a l u a t e c r u d e l y

t h e r i s k s t o nonhuman o r g a n i s m s . The p r o b l e m s i n e v a l u a t i n g t h e

r e s p o n s e r e l a t i o n s h i p b e t w e e n e x p o s u r e and a c t u a l d o s e r e c e i v e d

by t h e o r g a n i s m a r e t h e same f o r a n i m a l and p l a n t t e s t s a s i n

human h e a l t h a s s e s s m e n t s ( s e e p r e v i o u s s e c t i o n ) . P r e d i c t i o n

t o o l s , s u c h a s c o m p u t e r m o d e l s o f o r g a n i s m b e h a v i o r , and m o d e l s

t h a t assume u n t e s t e d c h e m i c a l s w i l l a c t i n a s i m i l a r f a s h i o n a s

t e s t e d c h e m i c a l s o f s i m i l a r m o l e c u l a r s t r u c t u r e c a n a l s o be u s e d

f o r a f i r s t a p p r o x i m a t i o n . I n many c a s e s , h o w e v e r , t h e

e n v i r o n m e n t a l e f f e c t s w i l l be u n d e r e s t i m a t e d by u s i n g t h e s e d a t a

a l o n e . A s a c o n s e q u e n c e , i t i s b e s t t o d e v e l o p a d a t a b a s e t h a t

a l l o w s i n f o r m a t i o n f r o m a l l l e v e l s t o be u s e d i n t h e r i s k

a n a l y s i s ( L e v i n e t a l . 1 9 8 4 ) . T h e t y p e s o f i n f o r m a t i o n n e e d e d

and t h e i r u s e a r e d i s c u s s e d h e r e .

S i n g l e s p e c i e s , a c u t e t o x i c i t y t e s t s . T h e i n f o r m a t i o n

d e r i v e d f r o m t h e s e t e s t s p r o v i d e s a g e n e r a l i n d i c a t i o n o f t h e

amoun t o f damage a c h e m i c a l m i g h t c a u s e i n a n e c o s y s t e m . S i n c e

i t i s now t h e mos t commonly a v a i l a b l e i n f o r m a t i o n , i t i s v a l u a b l e

a s a r a p i d a s s e s s m e n t t o o l f o r s c r e e n i n g s e n s i t i v e s p e c i e s and

r a n k i n g c h e m i c a l s . F i e l d c o n d i t i o n s o f e x p o s u r e , h o w e v e r , may be

v e r y d i f f e r e n t f r o m t h o s e o f t h e l a b o r a t o r y . F o r e x a m p l e ,

r a i n f a l l o f pH 4 . 5 h a s b e e n l i n k e d t o f i s h d e a t h i n t h e e a s t e r n

U n i t e d S t a t e s ( S c b o f i e l d 1 9 7 6 ) . L a b o r a t o r y a s s a y s o f o n e f i s h

s p e c i e s r e s p o n s e t o a c i d i t y , h o w e v e r , do n o t i n d i c a t e t o x i c i t y a t

t h i s p H . I n t b e f i e l d , t h e a c i d i n t e r a c t s w i t h s e d i m e n t s t o

r e l e a s e a l u m i n u m , w h i c h , i n t u r n , k i l l s t h e s e f i s h ( s e e

F i g u r e 1 2 ) . T h i s e f f e c t was n o t a n t i c i p a t e d by t h e l a b o r a t o r y .

V a r i a t i o n i n c o n d i t i o n s w i t h i n e c o s y s t e m s c a n c a u s e l a r g e

v a r i a t i o n s i n t o x i c i t y o b s e r v e d . T h u s l a b o r a t o r y - g e n e r a t e d d a t a

may be much l e s s r e l i a b l e p r e d i c t o r s o f a c t u a l e f f e c t s when t h e

r e s p o n s e s o f e n t i r e c o m m u n i t i e s a r e b e i n g e v a l u a t e d . F u r t h e r

p r o b l e m s w i t h a c u t e t e s t s a r e : ( 1 ) t h e y g i v e no I n d i c a t i o n o f

52

Figure 12. Differences in fish mortality (indicated by belly-up condition) depending on water pH and the environmental availability of aluminum. Trout survive to a lower pH under laboratory conditions without sediments (A) compared to field conditions (B) where toxic levels of aluminum (A1) can be leached from watershed soils and lake sediments (Adapted from Levin et al . 1984).

53

c h r o n i c t o x i c i t y , ( 2 ) t h e s p e c i e s f o r w h i c h i n f o r m a t i o n i s

a v a i l a b l e may n o t be a n a d e q u a t e s u r r o g a t e f o r s p e c i e s f o u n d I n

t h e a c t u a l s y s t e m , and ( 3 ) t h e e n v i r o n m e n t may i n t e r a c t w i t h t h e

p o l l u t a n t , i n c r e a s i n g i t s t o x i c i t y , a s i n m e t h y l m e r c u r y p r o d u c e d

f r o m e l e m e n t a l m e r c u r y by m i c r o o r g a n i s m s (Wood 1 9 7 4 ) .

S i t e - s p e c i f i c p o l l u t a n t t e s t i n g . S i n g l e s p e c i e s , a c u t e

t e s t s c a n be made more u s e f u l f o r e v a l u a t i n g damage i n s p e c i f i c

e c o s y s t e m s i f t h e s p e c i e s c h o s e n f r o m t h e s i t e a r e ( 1 )

e c o n o m i c a l l y i m p o r t a n t , ( 2 ) e n d a n g e r e d , ( 3 ) s p e c i e s t h a t c o n t r o l

t h e p o p u l a t i o n s o f o t h e r s p e c i e s t h r o u g h p r e d a t i o n o r r e s o u r c e

p r o c e s s i n g ( c r i t i c a l s p e c i e s ) , ( 4 ) v a l u a b l e a s e a r l y w a r n i n g

i n d i c a t o r s , o r ( 5 ) d o m i n a n t . I f a c u t e t e s t s a r e c o n d u c t e d w i t h

s p e c i e s c h o s e n u s i n g t h e s e p a r a m e t e r s , e x t r a p o l a t i o n o f t e s t

r e s u l t s t o p r e d i c t i o n s o f a c t u a l e c o s y s t e m r e s p o n s e s t o t o x i c

c h e m i c a l s w i l l be more s u c c e s s f u l .

O r g a n i s m b e h a v i o r a l s t u d i e s . S p e c i e s a r e o f t e n more

s e v e r e l y damaged t h a n i s p r e d i c t e d by a c u t e t e s t s b e c a u s e

s u b l e t h a l q u a n t i t i e s o f t o x i c c h e m i c a l s c a n c a u s e s u b t l e s h i f t s

i n b e h a v i o r . F o r e x a m p l e , g r a s s s h r i m p p o p u l a t i o n s i n some l a k e s

I n t b e U n i t e d S t a t e s d e c l i n e d a f t e r b e i n g e x p o s e d t o s u b l e t h a l

q u a n t i t i e s o f t h e i n s e c t i c i d e m l r e x b e c a u s e t h e i r a b i l i t y t o

e s c a p e t h e i r p r e d a t o r , p i n f i s h , was i m p a i r e d ( T a g a t z 1 9 7 6 ) .

A c u t e t o x i c i t y t e s t s s h o u l d be c o n d u c t e d u s i n g two o r more

i n t e r d e p e n d e n t s p e c i e s .

M i c r o c o s m s . The p r e s e n c e o f a n a b i o t i c s u b s t r a t e and a

d e c o m p o s e r c o m m u n i t y i n an a c u t e t e s t c a n c h a n g e s p e c i e s r e s p o n s e

t o a t o x i c o h e m i c a l . F o r e x a m p l e , cadmium i n s o l u t i o n i n t h e

C h e s a p e a k e Bay h a s a d v e r s e l y a f f e c t e d m i c r o o r g a n i s m s whose

f u n c t i o n i s n i t r i f i c a t i o n , t h e l a c k o f w h i c h c o u l d l e a d t o a

r e d u c t i o n i n t h e f o o d s u p p l y o f f i s h . To t e s t f o r t h i s k i n d o f

r e s p o n s e , a s o i l c o r e c a n be f l u s h e d w i t h a t o x i c c h e m i c a l t o

i d e n t i f y t h e e f f e c t s o n m i c r o o r g a n i s m s t h a t decompose o r g a n i c

54

m a t t e r . The s m a l l s i z e o f s u c h a m i c r o c o s m c a n l i m i t t h e d e g r e e

t o w h i c h t h e m i c r o c o s m a c c u r a t e l y r e f l e c t s t h e f i e l d r e s p o n s e .

I n summary , t h e f o l l o w i n g c a t e g o r i e s o f i n f o r m a t i o n c a n be

c o l l e c t e d t o b e t t e r p r e d i c t t h e e f f e c t o f t o x i c c h e m i c a l s o n

e c o s y s t e m s :

• C h a n g e s i n f u n c t i o n s and p r o c e s s e s t h a t m o b i l i z e and

t r a n s f e r n u t r i e n t s and e n e r g y .

• R e s p o n s e o f c r i t i c a l s p e c i e s t h a t p l a y f u n d a m e n t a l r o l e s

i n t h e s t r u c t u r i n g and f u n c t i o n i n g o f e c o s y s t e m s .

• B a s e l i n e d a t a o n u n a f f e c t e d e c o s y s t e m s a s b a c k g r o u n d f o r

e s t i m a t i n g c h a n g e due t o c h e m i c a l c o n t a m i n a t i o n .

• E x p e r i m e n t a l r e l e a s e o f c h e m i c a l s w i t h a p p r o p r i a t e

m o n i t o r i n g o f i m p a c t e d and c o n t r o l e c o s y s t e m s .

I n t e g r a t e d A s s e s s m e n t M o d e l s

I n r e c e n t y e a r s , a number o f t e c h n i q u e s h a v e b e e n d e v e l o p e d

t o a t t e m p t t o b r i d g e t h e d a t a g a p s o f t e n e x i s t i n g f r o m e m i s s i o n s

t o e x p o s u r e t o d o s e t o h e a l t h e f f e c t s ( s e e F i g u r e 9 ) - Some

r e q u i r e l i t t l e d a t a a n d , a s a r e s u l t , o n l y g i v e a r e l a t i v e

m e a s u r e o f r i s k . O t h e r s a r e more d e t a i l e d and d a t a i n t e n s i v e b u t

g i v e some s o r t o f a b s o l u t e e s t i m a t e o f i m p a c t . T h e s e m o d e l s

t h e r e f o r e p r o v i d e a b r i d g e b e t w e e n t h e h a z a r d a c c o u n t i n g a n d r i s k

c h a r a c t e r i z a t i o n s t a g e s shown i n F i g u r e 5 . H e r e we d i s c u s s a f ew

o f t h e mos t commonly u s e d m o d e l s i n t h e U n i t e d S t a t e s . ( S e e a l s o

C h a p t e r 6 o f G o l d m a n e t a l . 1986 f o r a d i s c u s s i o n r e l a t e d

s p e c i f i c a l l y t o h a z a r d o u s w a s t e s . )

S e m i q u a n t i t a t i v e M e t h o d s . T h i s s e c t i o n p r o v i d e s a g e n e r a l

d e s c r i p t i o n o f s e l e c t e d p r o c e d u r e s f o r c o n d u c t i n g s e m i ­

q u a n t i t a t i v e r i s k c h a r a c t e r i z a t i o n ( s e e T a b l e 3 ) . T h e

q u a n t i f i c a t i o n i s l i m i t e d t o s c o r i n g o r r a n k i n g f o r a n i n d i c a t i o n

o f r e l a t i v e r i s k s . T h e n e c e s s a r y i n f o r m a t i o n may be o b t a i n e d

T a b ! * 3 . Q i w a c i e r i a t l o a o f M I « O I « 4 * a a l o . t a n i l U U * e o a i a r d / r l a f c iiNiwm M U K X U

r i f u r o i

• n a l v a l a o o a p o n e a t

C b o » l o a l h a z a r d

o l a a a i r i o a u a o d o a a - r e s p o n s e d a t a

Q i a i l a l h a z a r d

a o o r l n i ( H i P P S ' l

H u a r d o u i w a s t e • 11* r a n k i rig

H u a r d

•oaounilBg, [ T o t a l q u a n t i t i e s o f . o b e a l o s l I D r e a l o o loT 1 m a r a s t

• o l c o n s i d e r e d N o t o o n s l d e r e d S c o r e b a a e d o n t o t a l U . S . p r o d u c t i o n

S c o r e b a a e d o n

q u a n t i t i e s u r o a a n t

• e l e a a * * t o u>a

o n d r o o a o n t ( a a U a s J o n s )

C o o o s n t r a t l o n I D

U i a a m i r o o B o o t

E x p o B U T a s / d o a a i

t o b i s a n a a n d

e o o a v a t t B e

• o l c o n s I d a r e d

T a n d o n o y f o r p a r a l a t a n o * ,

• o b i u t r .

b l o a o o i a a u l a U i m a | b o o o o f t l d j

• o t c o n s i d e r e d

H o t c o n s i d e r e d

H o t o o n o l d a r e d

S o o r a T o r r a l e a a a p o t e n t i a l b a a e d o n v a p o r p r e s s o r i

b l o a c c u a u l a l l o n s o o r a b a a o d o n w a t a r / o e t a n o l p a r l l t l o n c o e f f i c i e n t

a i t a l a n c a of

a a b l a n t s t a n d a r d

S c o r e b a s o d o n w a s t e c o n t a i n * *

t v p a

S o o r o a b a a e d o n d l a p e r s l o n I n d i c a t o r s ( a . g . , w s e l e c h a r a c t e r i s t i c s , • q u i f a r d a p t b )

S c o r e s L a s a d o n ( r o u n d w a t e r u s a , n e a r a s I w a l 1 d l s t a n c e

• l a k i

C h a r a o t o r l i a u o n

i d v e r a e e f f e c t a o f

• s p o a u r a s / d o m m

F i n s ) a a a a a a s a a t stuuri ( b a a l t h o r e o o a } a l » a / f a c t )

S c o r i n g b a a e d o n • • p o r t a n a l y s i s o r • a i f b t o f ev I d e c o a o f a d v a r a a o f f o o t

f t l a a r l l y q u a l i t a t i v e I n d l o a a o f h a z a r d

Q u a n t 1 l a U « e

w a l t a t t o o s o f

d o a s - r e s p o n s e

V a r i o u s d o I r e s p o n s e f u n c t i o n s

S c o r i n g b a s e d o n a v a i l a b l e d a t a f o r a d v o r a o a f T a o t a ( e . g . , c a n c e r , a c u t a l e t h a l 1 I f )

S o o r a b a a s d O D w e i g h t e d c o m b i n a t i o n o f a b o * a s c o r e s

S c o r e b a a e d o n w a s t e l o a l o l t * ( d o a a n o t c o n s l d a r f o o d c h a i n p a t h w a y )

C c v j p o a o d s o o r a b a a e d o n w e i g h t e d o c a b i n a t i o n o f a b o v e a o o r a a

i n d a r a o n o t a l . i n d e r a o n o t a l . S a i t b a n d r i n g J a t o o U 3 L P 1 19&?

I 9 M ; I U C 19>2; 1 9 M , 1 ,63; 19&7 W B O / U M P / H o r l d O U a j r a k a n d F l n k a l B a o k 1967 I 9 M : 0 3 0 a 1 9 4 6 b

H a z a r d o u s a i r f o i l u l a n t P r i o r i t l i a U o n S y s t a s

56

f r o m t h e l i t e r a t u r e o r s t a n d a r d d a t a b a s e s , and t h e s e t e c h n i q u e s

c a n be u s e d t o i d e n t i f y q u i c k l y t h o s e h i g h p r i o r i t y h a z a r d s

r e q u i r i n g f u r t h e r a n a l y s i s . I n g e n e r a l , t h e y r e q u i r e l i t t l e

s i t e - s p e c i f i c i n f o r m a t i o n .

D e p e n d i n g o n t h e q u e s t i o n b e i n g a s k e d , h o w e v e r , t h e s e

m e t h o d s may n o t p r o v i d e s u f f i c i e n t a c c u r a c y , r e l i a b i l i t y , and

d e t a i l t o be u s e d a s f i n a l i n p u t t o r i s k management d e c i s i o n s .

The f o l l o w i n g i l l u s t r a t e a p p l i c a t i o n s o f t h e s e s e m i q u a n t i t a t i v e

p r o c e d u r e s :

• R e s e a r c h i s t o be c o n d u c t e d o n h e a l t h e f f e c t s o f

c u r r e n t l y e x i s t i n g a m b i e n t p o l l u t a n t s i n a h e a v i l y

i n d u s t r i a l i z e d a r e a . A l i s t o f m a j o r c h e m i c a l

c o n s t i t u e n t s i s a v a i l a b l e . A s e m i q u a n t i t a t i v e r a n k i n g o f

t h e h a z a r d f r o m e a c h o f t h e s e c o n s t i t u e n t s i s o b t a i n e d a s

a n a i d i n p l a n n i n g t h e r e s e a r c h p r o g r a m .

• A c o r p o r a t i o n I s p r o p o s i n g t o I m p o r t a new c h e m i c a l I n t o

t h e e c o n o m y . A s e m i q u a n t i t a t i v e r i s k a s s e s s m e n t i s t o be

u s e d t o p r o v i d e a p r e l i m i n a r y i n d i c a t i o n o f t h e n e e d f o r

f u r t h e r a n a l y s i s by t h e r e g u l a t o r y a g e n c y .

• A new l a w i s p a s s e d m a n d a t i n g a n a g e n c y t o d e v e l o p

r e g u l a t o r y c o n t r o l o v e r a c l a s s o f c h e m i c a l s w i t h i n t h e

n e x t 5 y e a r s . S e m i q u a n t i t a t i v e r i s k a s s e s s m e n t s e t s

p r i o r i t i e s f o r r e g u l a t i o n o f t h e c h e m i c a l s .

• A n I n i t i a l r a n k i n g o f a l t e r n a t i v e s i t e s f o r a new l a n d

d i s p o s a l a r e a c a n be o b t a i n e d by s e m i q u a n t i t a t i v e r i s k

a s s e s s m e n t .

• S e v e r a l p r e v i o u s l y u s e d l a n d d i s p o s a l s i t e s h a v e b e e n

d i s c o v e r e d t o be c o n t a m i n a t i n g t h e e n v i r o n m e n t .

S e m i q u a n t i t a t i v e r i s k a s s e s s m e n t i s u s e d t o o b t a i n a n

i n i t i a l r a n k i n g o f p r i o r i t i e s f o r c l e a n u p .

T a b l e 3 l i s t s a few o f t h e a v a i l a b l e i n d e x i n g m e t h o d s i n

t h i s c a t e g o r y , w h i c h a r e d i s c u s s e d h e r e .

57

Chemical hazard classification. The most straightforward method for preliminary evaluation of hazards from chemicals is to use existing classification schemes that typically rank hazards In categories such as HIGH, MEDIUM, or LOW carcinogenio potential (Anderson 1984; IARC 1982; WHO/UNEP/World Bank 1987). These approaches are based almost solely on relative effects for a normalized exposure level, and therefore do not account, for example, for substantial differences in concentration or for populations exposed in various ways. Also, these methods do not permit the evaluation of combined hazards from more than one chemical.

Assessment based on dose-response data. Generic potency (dose-response) data can give more detail on the relative ranking of.hazards presented from various constituents (Anderson 1984; Anderson et al. 1983; Ozkaynak and Finkel 1966; USEPA 1986b; Hushon and Kornreicb 1984). For example, i f estimates of quantities of the hazardous chemical are available (e.g., quantity of a pesticide used), multiplying those quantities by the published potencies gives a measure of the relative hazard, which can be used for an initial comparison with other chemicals.

In using this method to compare hazards of alternative chemicals, caution must be exercised to avoid comparing different potency measures (e.g., those based on the mean and those at the 95 percent confidence interval). Unfortunately, i f there are no published data for a particular chemical, considerable expertise and resources are required to develop additional dose-response data.

Chemioal hazard scoring. The methods discussed above may be extended by incorporating scoring for the other analysis components in the left-hand column of Table 3. The Hazardous Air Pollutant Prioritization System (HAPPS) was developed for the USEPA for prioritizing potential air pollutants and is designed to be implemented by persons with limited expertise using

58

w e l l - d e f i n e d , r e a d i l y a v a i l a b l e d a t a . U n f o r t u n a t e l y , s e l e c t i o n

o f s c o r i n g m e t h o d s and w e i g h t s t o c o m b i n e s c o r e s I s somewhat

a r b i t r a r y i n t h i s s y s t e m , and s e n s i t i v i t y a n a l y s i s s h o u l d t h u s be

a p a r t o f i t s a p p l i c a t i o n .

F l n g l e t o n e t a l . ( 1 9 8 5 ) d e s c r i b e a n a p p r o a c h t o e x t e n d i n g

t h i s p r o c e d u r e t o o t h e r t h a n a t m o s p h e r i c e m i s s i o n s , and H u s h o n

a n d K o r n r e i c h ( 1 9 8 4 ) p r o v i d e a r e v i e w o f v a r i o u s a t t e m p t s t o

d e v e l o p s i m i l a r m e t h o d s .

H a z a r d o u s w a s t e s i t e r a n k i n g . A s c o r i n g me thod d e s i g n e d f o r

u s e i n c o m p a r i n g , o n a r e l a t i v e b a s i s , t h e h a z a r d s o f v a r i o u s

e x i s t i n g h a z a r d o u s w a s t e d i s p o s a l s i t e s h a s b e e n d e s i g n e d by t b e

USEPA ( 1 9 8 2 ) . I n t h i s method t h e v a r i o u s s i t e c h a r a c t e r i s t i c s

a r e c o n v e r t e d t o s c o r e s u s i n g t a b l e s p r o v i d e d , and t h u s t h e

m e t h o d i s r e l a t i v e l y s t r a i g h t f o r w a r d t o a p p l y . A l l p a t h w a y

c o m p o n e n t s e x c e p t t h e f o o d c h a i n a r e c o n s i d e r e d t o some e x t e n t .

The r e s u l t s o f t h i s and s i m i l a r a p p r o a c h e s ( s e e , f o r

e x a m p l e , B a r n t h o u s e e t a l . 1986) m u s t be c a r e f u l l y i n t e r p r e t e d

b e c a u s e o f t h e q u a l i t a t i v e n a t u r e o f t h e s c o r e s p r o d u c e d . I n

many c a s e s f u r t h e r q u a n t i t a t i v e r i s k a s s e s s m e n t w o u l d be r e q u i r e d

t o make r i s k management d e c i s i o n s .

Q u a n t i t a t i v e R i s k A s s e s s m e n t M e t h o d s . Q u a n t i t a t i v e r i s k

a s s e s s m e n t c a n n o t be r e d u c e d t o a s m a l l s e t o f s t a n d a r d

c o m p u t a t i o n a l p a c k a g e s b e c a u s e i t i s a n I n t e g r a t e d p r o c e s s

a p p l i c a b l e t o a w i d e r a n g e o f o f t e n u n i q u e e n v i r o n m e n t a l

c o n c e r n s . E a c h a p p l i c a t i o n i n w h i c h a d e t a i l e d a n a l y s i s i s t o be

c o n d u c t e d r e q u i r e s a s e p a r a t e d e t e r m i n a t i o n o f t h e mos t

a p p r o p r i a t e a n a l y s i s t e c h n i q u e s t o be u s e d . A s a r e s u l t , t h e

m e t h o d s d e s c r i b e d i n t h i s p a r t a r e i n t e n d e d p r i m a r i l y a s e x a m p l e s

r a t h e r t h a n a s e t o f a l t e r n a t i v e s f r o m w h i c h a me thod i s t o be

s e l e c t e d ( s e e T a b l e 4 ) .

T h e r e a r e , h o w e v e r , f a i r l y s t a n d a r d c o m p u t a t i o n a l r o u t i n e s

f o r s p e c i f i c c o m p o n e n t s o f t h e a n a l y s i s ( e . g . , m o d e l s f o r

s i m u l a t i n g d i s p e r s i o n o f p o l l u t a n t s i n g r o u n d and s u r f a c e w a t e r

Table 4. Q ia rac le r l a t l c s of selected qua.ntllv.Uve r i sk easeassent aathoos

Figure 5 analysis component

CcoperUBental models (GEO TO I)

Risk-coat analysis model

Land diapoaal screen!ng model

Accident r i s k as so sonant model i

Hazard icoountlng

Envlronaental pathway

•valuat ion

Total quanti t ies of Chen leal i n region of Interest

Rel eases to the • nv 1 ronaant

(eal salons)

Concentrations I the environment

Eiposures/doaea to huaana and ecosystems

Risk ChoracterlzaUonC

Adverse effects of •inoaurea/doaea

Final saseasaent measure (health o r ecosystem effect)

Not considered

Specified by

Deteral ned by assa ricai between ooapartaantd ( a i r , s o l i , ground and surface water) and by pa r t i t ion coefficient

Based on coo puted concentrations and bloaass pa r t i t ion coeff ic ients

Not oonsldered

Exposure

Provided In Input database

Function of tree to ant/ transportation/ disposal technologies

Based on defined sat of alternate em lrooaenlel reglaes

Based on deflned sot of al ternste population datnsl-t lea and oooayateas

Scores for r i s k s to huaans and a cosy at eai a

Relat ive r i sk versus coat for control al ternatives

Hot considered

Hail BID. ai l ov ­able to avoid umianteo affects Is obtained by back ca l cu l a t i on

Dispersion par t

unit of effluent calculated

Hailaua exposure assumed fraa use of well 500 f t . from souroe

H a i l B U B acceptable concentration sat as Input

Constralnta on land diapoaal to avoid unacceptable effects

Proa system flow diagrams

Frca est l a s t * of accident p robabi l i ty

Proa d ispers ion models

From population d i s t r i b u t i o n

Proa dose-response data

Risk curves fer­a l terns t lves

HcKone e l a l . 1967 ; Ketone 1965; Smith et a l . I960; Layton and HcKone 1986

USEP1 tQSAs USEPi 1986a, 1986c; Flngleton et a l . 19B6

Boykin 1967

60

and In the atmosphere). The quantification obtained from these methods should inolude at least indirect association with some measures of adverse human health or environmental effect (e.g., a comparison of ambient concentration with a health-based standard).

Com'partmental models. In multimedia compartmental models, the landscape of concern is divided into discrete compartments (e.g., a i r , s o i l , groundwater, surface water, sediment, biomass). Transfer of chemicals among compartments is estimated based on concentration in compartments and intercompartmental flows (e.g., flow of polluted groundwater into surface water).

In each compartment the chemical of concern is assumed to be incorporated into various compartment components (e.g., rock and groundwater in a lower so i l compartment) according to partition coefficients estimated by a variety of techniques (Layton and MoKone 1986; Prasad 1987; Lyman et a l . 1962). Prasad's paper provides another example of how this approach can be used for qualitative ranking.

Tbe advantage of the compartmental modeling approach i s that quantitative estimates of chemical dispersion in the environment can be obtained rather quickly for application in sensitivity studies. This approach has been incorporated into a standard software package called GE0T0X (McKone et a l . 1987; McKone 1985; Smith et a l . 1980; Layton and McKone 1986). The limitation of the approach is that results are less accurate than those obtained by more detailed dispersion analysis. For this reason the model i s more applicable as a tool in preliminary policy analysis as opposed to detailed site-specific analysis.

Risk-cost analysis model. This model i s an i l lus t ra t ion of an attempt to conduct comprehensive analysis of waste management options (USEPA 1984a). Included in the analysis are (1) characteristics of a set of waste streams; (2) costs and degree of risk reduction with different control options for treatment,

61

transportation, and disposal; (3) options for alternative environmental settings with various assimilative and dispersive capacities; and (4) consequent human population densities and aquatic ecosystems that would potentially be exposed to the residuals in waste streams.

The output of the model i s relative risk as a function of control cost. This output i s used in policy analysis to determine preferred hazardous waste technological controls. A primary limitation of this comprehensive modeling approach is the extensive data requirements. Considerable expertise is required to run the model and interpret the results.

Land disposal screening model. This model by the USEPA represents one of the most detailed and expl ic i t ly defined risk assessment procedures proposed for incorporation directly into the hazardous waste regulatory process (USEPA 1986a, 1986c; Flngleton et a l . 1986). The purpose of the model is to determine whether a particular land disposal and treatment technology w i l l maintain the dose to exposed individuals at or below levels that prevent unacceptable adverse health effects. The procedure, in effect, back-calculates dispersion to relate an acceptable exposure level to maximum release rate at the land disposal s i te . Relatively sophisticated geophysical and engineering models are included to simulate pollutant transport and fate. To deal with the uncertainty accompanying the range of possible site characteristics, probability simulations, such as the Monte Carlo techniques, are conducted with the distributions of relevant parameters as input.

The basic approach i s conceptually sound and represents an advanced application of risk assessment in formulation of hazardous waste policy. The substantial resources required in terms of expertise to compile the extensive input data, run the model, and interpret the results can be expected to l imit application.

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Aocident risk assessment models. The previous models are applicable to more or less continuous, low level releases of hazardous chemicals. Here we refer to single release, low probability, potentially high impact events. As discussed in the section on "Environmental Pathway Evaluation," the analysis proceeds from development of system descriptions that identify possible failure modes. Estimates are developed of probability distributions for failure rates and associated release quantities. Given the release rates, the subsequent dispersion, exposure, and dose-response are estimated using techniques in many ways similar to those for the lower continuous releases. The results of the analysis are typically expressed as curves relating the number of individuals affected versus the probability of occurrence of an accident of that severity. These techniques have been extensively developed and used in the nuclear and chemical industries (Boykin 1987).

Risk Management

Risk management is an integral part of risk assessment because management questions are the in i t ia t ion point for every assessment. No universal assessment approach is suited to a l l possible management questions. Tbe constraints of management also set pr ior i t ies within the assessment. Although the participants did not discuss management options in detai l , or the hierarchy of causes that lead to risks (Hohenemser et a l . 1983)« they did emphasize that various approaches are possible, depending on the system boundaries of the management system (and risk assessment). They also pointed out that in practice risk management of chemicals i s often implemented as exposure management, since i t is d i f f icul t to affect directly the factors that lead from exposure to dose and health effects. Table 5 l i s t s some potential exposure management methods that might be considered at various stages in the flow cycle of a chemical

63

Table 5 . Exposure management techniques

Exposure Manufac-oanagement technique Mining ture Transport Storage Use

Information dissemination Worker t raining Container labeling Public awareness campaign

S i t ing F a c u l t i e s Transport routes

Process change Lower inventories Less leakage Recycling Transport less hazardous

intermediates

Substitution Eliminate from market Alternative product available

Emergency response Real-time monitoring Evacuation plans

Manage contaminated environment Quarantine Decontaminate

Waste destruction Land incineration Marine lnolneration

Haste disposal With treatment Without treatment

Hote: This table shows examples of the range of exposure managenent options that may be available in different points of the flow cycle. The effectiveness of eaoh option in achieving exposure reduction in terms of administrative, temporal, cost, and other factors would need to be compared. Each chemical flow cycle would have a different pattern of options and comparative effectiveness.

64

technology. Note that some options, such as worker education, are sometimes not thought to be part of the system. It may well be, however, that the cost per unit exposure avoided or reduced could be substantially less with these nonequipment-oriented approaches. (See page 71, "Importance of Clean Technology," for some Ideas about establishing priori t ies for management of wastes.)

Perception of Risk and Communication of Assessment Results. To take advantage of risk assessment, effective communication techniques need to be developed based on an understanding of risk perception in the society.

Most citizens are no longer wi l l ing to accept the pronounced Judgments of "experts" about which risks are "acceptable." As the participants learned, the concept of risk to human welfare i s quite dependent on the level of that welfare. For example, the poor farmer who has no savings cannot risk pest damage to his crop for the sake of avoiding longer term adverse effects of chemical pesticides. This desperately short-term perception increases the willingness of individuals to accept higher risks from act ivi t ies that are obviously beneficial to them. The degree to which people distinguish between voluntary and involuntary risk i s not yet established for developing countries.

Religious convictions may hold that death is simply the beginning of another cycle of l i f e and i s therefore not an appropriate measure of r isk. Since death, in these different cultures, i s not to be influenced or Judged by man, information on risk of death from proposed technologies might be questioned or treated indifferently by decision-makers. Another possibil i ty is that the fear of cancer might not affect risk management act ivi t ies as much as i t has in the United States. The probability of human suffering, on the other hand, may readily be given weight in decision-making.

Each society w i l l have to establish i t s own cr i t e r ia for evaluating public concern because of cultural differences and the

65

dif f icul t ies for expatriate observers to interpret correctly attitudes in a foreign community. There are some indications of general human response to r isks , however, that should be useful unless disproved in a particular country. People seem to be more concerned with catastrophic events, irreversible consequences, impacts on children, risks that are unclear to scientists, personally specific risks (identifiable victims), and risks over which they have l i t t l e control.

The often subtle, delayed, nonspecific nature of toxic chemical effects means that the public may not be receptive to the warnings from risk assessors—especially in the context of Third World poverty. At the same time their fear of new technology also may be unwarranted.

Communication of uncertainty and the probabilistic nature of science are di f f icul t at best without the complications accompanying perception of chemical r isks. In addition, the risk manager is usually attempting to change attitudes and behavior. Public participation in the assessment (and in development planning in general) i s clearly one element of successful implementation of risk management.

Options. Alternative courses of action may be proposed at the start of risk assessment, or actually be generated as a result of the process. The affected parties (workers, residents, and wildl ife enthusiasts as well as government and industry off ic ia ls) are the source of new ideas for risk reduction. Early Involvement of these groups paves the way for effective communication, negotiation of conflicts, and eventual acceptance of a management program.

The option of doing nothing must always be considered because, once assessed, i t can serve as a benchmark against which to compare other risks and the costs of mitigation. Whereas, at the outset, the manager is challenged with doing something, the end result of risk assessment may be to recommend enduring the

66

risk and deploying available resources to some other societal problem.

Risk Comparison. As we have seen, risks vary considerably in kind as well as severity. Risk management should point out the comparability or differences of a new risk vis-a-vis more familiar ones. Mixing voluntary and involuntary risks is unfair (and dangerous for the manager) because of the wide difference in perception and acceptance. A more helpful comparison is among closely related ac t iv i t ies . For example, the risk of eating fish containing PCBs may be compared to the risk of a protein-deficient diet resulting from not eating the f ish, or the risk of working in a nearby chemical factory may be compared with riding a bus to a distant but less hazardous Job.

Economics of Risk Reduction. Monetary value is the common denominator used in benefit/cost analysis for decision-making i n much of risk management. At the outset, however, most assessors (and economists) do not try to monetize human l i f e . No method has been found that can weigh in the feelings of those persons concerned; thus, a l l methods are unsatisfactory on ethical grounds. Instead, the more useful and acceptable practice is to view the benefits of improved management of hazardous chemicals as reductions in r isk.

A group at risk (that has been properly Informed about i t ) may reveal how much they are wi l l ing to pay to avoid the risk or how much they demand to be compensated i f they Incur the r isk. A measure of risk valuation, for example, is the wage differential between a Job i n a hazardous chemical factory and similar employment in a safe working environment. Or the difference in housing prices between an area adjacent to a chemical plant and some distant location can measure r isk. Of course, the ab i l i ty to pay greatly influences willingness to pay and poor people often have no real choice.

A more direct valuation of chemical risks is by using the

67

market prices of goods and services (e.g., tbe loss in value of vegetables rendered Inedible because of uptake of a heavy metal, or wages lost to workers made 111 by a release of toxic fumes). Similarly, the cost of a "shadow project" to avoid a r isk may indicate i t s monetary value (e.g., the cost of restoring a freshwater fishery that would be damaged by cyanide wastes, or the cost of alternative food supplies i f present sources become chemically contaminated).

Cost-effectiveness analysis can indicate the least expensive way to meet an agreed-upon goal of risk reduction. Unless these calculations are made, money may be wasted by choosing the wrong risk management strategy. For example, a measure of r isk may be the dose of a chemical accumulated from ingestion of contaminated water and food. The dose-response curve may indicate a proportional reduction in adverse health effect for each increment of dose that i s avoided down to a no observable effects level , the public health goal. Different management options such as providing replacement food, water treatment, or elimination of the chemical source vary in cost and effectiveness ( i . e . , amount of dose avoided per expenditure). The option that w i l l achieve the goal at the least cost can thus be identified. The actual implementation plan w i l l include pol i t i ca l and social factors also and may combine several technoeconomic options, but the cost-effectiveness of each should be known.

A related economic analysis can show the optimum amount of risk reduction (concentration of the hazardous chemical or some other measure related to health or ecosystem effect). The benefit (damage costs avoided) of risk reduction is compared with tbe costs. The total net cost to society i s seen to reach a minimum at that degree of risk reduotlon where the marginal benefit of an increment of reduction equals the marginal cost of i t s achievement, as shown in Figure 13-A. In practice, the reduction of risk may be stepwise and not continuous depending on the mitigation action taken. In Figure 13-B, several discreet technological approaches for risk reduction have different costs.

66

Figure 13-A. Optimal levels of risk reduction. The least total cost and the optimum degree of control can be derived from summing the curves in an ideal (smoothly varying) situation.

Figure 13-B. Real is t ical ly, control or reduction of risks comes in technological packages or steps. To the cost of each technology must bemadded the remaining damage costs. Both no control and a very high degree of control are seen to have a greater total cost than partial control options.

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To each risk reduction cost must be added the damage costs from the remaining risk of adverse effects to get tbe total cost to society. An action is either taken or i t is not. If no risk reduction action i s taken, the f u l l damage costs are incurred. A high cost action (E) may reduce damages to almost nothing. In between l i e actions with other associated costs. In Figure 13-B, the choice of management would appear to be (B) or (D), giving the lowest total net cost to society.

FINDINGS AND RECOMMENDATIONS

Participants found that existing risk assessment methods are useful for developing countries for controlling chemical hazards. Substantially more effort w i l l be needed, however, to adapt the methods to differing cultural and pol i t ica l systems, to obtain and transfer necessary data on health and ecosystem response, and to build indigenous assessment capabilities. In this last section, some of the specific findings and recommendations are discussed in more detai l . They deal not only with tbe hypothesis of the workshop but the sociocultural setting of risk management.

Future Trends in the Region

Industrialization upon a base of agricultural self-sufficiency continues to be a common development strategy. Sophisticated chemical compounds are valuable in both of these sectors, and the quantities as well as varieties of chemicals used w i l l grow rapidly. Substitution for imports with chemicals manufactured and formulated locally i s also becoming more common, motivated by economic efficiency.

A major consequence of industrialization is the increase in risk of contamination of ground and surface water. The so-called "higher uses" of water, which command a higher price, are

70

industry and public water supply. Typically, in an industrialized area, most of the surface water and substantial portions of underground aquifers w i l l come in contact with chemical processes or wastes, including mixed municipal sewage. By contrast, water in an essentially undeveloped agricultural economy w i l l be exposed only to pesticide and f e r t i l i z e r runoff, affecting only a small proportion. Lower river basin water supplies w i l l thus become vulnerable to contamination by a number of toxic materials threatening aquatic l i f e and human health with hazards not previously experienced.

The participants were reminded that the transfer of technologies oocurs in surges, thereby taxing the ab i l i ty of host countries to understand and adapt to even the direot benefits of industrialization, much less the r isks. It i s d i f f icu l t enough to ensure the new technologies are working as they should for produotion, besides monitoring and managing them to avoid adverse side effects to the environment or human health. The general acceptance and practice of environmental impact assessment is only now occurring; however, the long period of adaptation and t r i a l s for environmental impact assessment is an excellent base for adding risk assessment methods. Their implementation should come quickly as environmental impact assessors add the closely related s k i l l s for identifying, accounting, and evaluating hazards from toxic chemicals. Practical concerns for worker health and safety w i l l also lead the way to acquiring hazard data and risk assessment capabilities, which can then be deployed to manage risks to public health and ecosystems. Another reason for optimism i s that economic growth i t s e l f generates the resources and public awareness that can support po l i t i ca l w i l l to address problems of hazardous chemicals and wastes.

Priori ty Chemioals

The participants developed a priority l i s t of chemicals

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Table 6. Chemicals requiring priority attention in developing countries

Metals; Cadmium, chromium (bexavalent), lead, mercury Pesticides: DDT, arsenlcals, paraquat Solvents: Trichloroethylene, perchloroethylene, benzene Cyanide (metal processing wastes) Polychlorinated biphenyls (PCB) Volatile organic compounds (VOC): Chloroform, carbon tetrachloride Highly toxic organic intermediates: Aniline, phosgene Bulk chemicals: Chlorine, ammonia

(Table 6) based on tbe current actual concerns and ongoing action programs of the countries represented. Obviously, other compounds may be or become important in a particular industrial area. Much information is available about the toxicity and environmental behavior of each of these compounds, and the data can be accessed by developing countries (see Appendix A). The means for mitigating risks and treating wastes seem also to be available at acceptable costs. Multinational research collaboration and exchange of experience can speed the development, transfer, and adaption of effective risk management programs.

Importance of Clean Technology

Risks from existing chemical processing and hazardous wastes must be dealt with as necessary, but future production, imports, and' use patterns must include the option of simply avoiding chemicals that cause problems. For at least some of the priority chemicals in Table 6, there are alternative ways of accomplishing the same Industrial or commercial objectives (see Table 7). A well-known example is substituting a membrane technique for the

Table 7- Potential for waste reduction opportunities across different Industry types

Company/Industrial characteristics Eianple industries

Operations In-process changes recycl lng

Process changes

Input substl tutlon

End product changes

Mature process teohnology. high-vol use product

Rubber Petroleun Commodity chemicals Paper products Lumber

+ + - - -

Very stringent product specifications or high--product quality demands for high-cost/high-prof It products

Pharmaceutical s Weapons Robotics Specialty chemicals

+

Frequently changing, high-tech products for Industrial use

Electronic components Medical equipment

• • + • •

Job shop processing or many different industrial products

Electroplating! Printing (

Foundries I Machine shops |

+ •

+ •

+

+

-

Changing production technology for oonmodl ly goods

Steelmaklng Nonferrous aetals Teitlles

* + •

Large-scale manufacture of consumer goods

Automobll es Appllances Consumer electronics Palnts

+ + * • +

Source: OTA (1986).

Hote: Plus ( + ) and minus (-) signs Indicate relative likelihood of the benefit of each category of action In each Industry.

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mercury electrode In chlorine manufacture, thus eliminating mercury contamination of water bodies. Another example is the recycling of chlorinated solvents in the United States. New dry-cleaning technologies conserve 99 percent of perchloroethylene. Overall, 1 pound of solvents i s recycled for every 2 pounds produced in 1987 - These changes were encouraged by more stringent environmental protection legislation mandated by the government (Storck 1987).

Integrated pest management (IPM) reduces the use of chemical pesticides by learning about the pest's l i f e cycle, behavior, and natural enemies. Chemicals are applied selectively to have the greatest effect, along with biological controls. Not only are the risks to applicators' health and to purity of local water supply reduced, but the costs of crop protection are usually lower (Postel 1987).

Cyanide salts are highly effective in electroplating metals but pose risks to workers from hydrogen cyanide formation and to organisms in waters contaminated with cyanide wastes. The costs of handling and decomposing cyanides are high enough to motivate research for substitute metal complexing agents. One such research effort i s a cooperative among several companies jointly funding work at a commercial laboratory. Cost-competitive, nontoxic methods w i l l soon be available, and these could be specified for new installations in developing countries (Battelle 1986).

Host country governments and industries should be alert to such "clean technologies" and require that nontoxic options at least be identified and evaluated whenever industrial expansions or introductions are permitted. Striotly enforced pollution and safety regulations w i l l provide an additional economic incentive to find clean technology options.

A recent study concludes: "There are no documented examples of healthy, growing American industries forced to move abroad because of environmental regulation or public concern in the United States. Thus, the f l ight of a few a i l ing industries from

74

the United States is not l ike ly to contribute in any significant way to tbe development of countries trying to build their industrial base" (Leonard 1985).

Although there is l i t t l e evidence that "dirty technology" i s being exported to pollution havens in developing countries, there are ample reasons to prohibit chemicals that have been banned or severely restricted in other countries. Increased notification and advisory information are being mandated by many industrial nations and are being promoted by international groups such as the OECD, WHO, and UNEP.

The U.S. Office of Technology Assessment, which has conducted pioneering studies of waste and waste reduction, has suggested that priori t ies and burdens of proof for waste management options should proceed as follows: (1) reduction/ prevention, (2) recycling/recovery, (3) treatment/destruction, and (4) control/disposal/discharge. Only i f i t was shown that (1) was not possible would an Industry be allowed to consider (2) and so on down the l i s t (OTA 1986).

<

Needs and Recommendations

The participants identified a number of ac t iv i t ies essential for effective chemical risk assessment and management in the developing countries of the region.

Acoess to Existing Databases. The participants believe that there is a real need for improved access to basic risk data. A comprehensive l i s t i ng and evaluation of existing databases useful in chemical risk assessment would be of great benefit. Such a l i s t i n g should be oriented toward developing country interests and capabilities and include fu l l comparative information about content, r e l i a b i l i t y , costs, and access. See Appendix A for a description of some of the more widely used databases and how to contact the institutions that maintain them.

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Organizational Roles in Chemical Risk Management.

Suggesting policies and practices often results in l i s ts of

actions that are obvious in the abstract but impractical or

difficult in reality. The following plausible Ideas should be

viewed as desirable goals and not as prescriptions.

Host country governments

• Inventory toxic chemicals by type, amount, location, imports, manufacture rates, storage, transport uses, and wastes. Establish a system for maintaining time series of these data. Consider establishing national registers that are compatible with the International Registry of Potentially Toxic Chemicals.

• Survey and monitor for health and ecosystem effects from priority listed toxic chemicals.

• Establish a. mechanism through which coordination can be achieved among agencies with Jurisdiction, concern, and responsibility ( i .e . , health, environment, agriculture, industry, customs, fish and wildlife).

• Devise a national strategy (based on risk assessment) to deal with existing risks from waste dumps and pollution.

• Require new chemical installations to have an acceptable risk, to evaluate siting options, and to consider clean technologies.

• Require foreign chemical industries to provide training in chemical risk assessment and risk reduotion technology as part of the import or manufacturing permit process.

• Establish enforceable standards for worker and public health and safety related to toxic chemicals and carry out fair and equitable enforcement.

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• Establish a risk assessment capability as part of tbe environmental Impaot assessment process to advise economic development o f f i c ia l s .

Multinational corporations

• Construct and operate foreign chemical installations to the same standards of risk management as in the home country.

• Comply with a l l host country environmental and health standards and regulations.

• Notify host country off ic ia ls of potential adverse consequences to health and the environment of any exported chemical technologies or materials, particularly i f banned or severely restricted in the country of origin.

• Perform environmental impact and risk assessments early in the planning of new ventures and share the results.

• Provide counterpart training in chemical technology and risk assessment for host country personnel.

• Develop improved methods for documentation and labeling of hazardous chemicals, particularly considering low levels of literacy in developing countries.

International organizations

• Continue dissemination of chemical information through the International Registry of Potentially Toxic Chemioals.

• Develop a hazard response information for each priority toxic chemical that could be part of the manifest to accompany a particular quantity of the chemical throughout i t s existence.

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• assist access to dose-response data and other ingredients of risk assessment existing in advanced countries and not requiring redetermination for application elsewhere.

• Provide an "honest broker" forum for discussion and resolution of scientif ic uncertainties and value judgments regarding chemical risk assessment.

• Disseminate results of risk assessments that are transferable and extract generalizable information so that risk assessment builds quickly on experiences and avoids expensive and time-consuming replication.

• Encourage cooperation and information exchange among developing countries.

Labeling and Manifest Guidelines. A l l containers, regardless of type, containing hazardous and toxic chemicals ( i . e . , wastes or raw chemicals to be used by industry) should be clearly labeled with the type of material and i t s hazards. Such labeling (1) w i l l alert workers and other persons handling the containers that special care is needed for worker protection, (2) should help minimize accidents, and (3) w i l l establish a paper tracking or manifest system. Whenever possible, pictograms and/or local languages should be included.

A manifest system, an essential part of hazardous chemicals management, should be able to document and trace chemical movement from "cradle to grave" and should serve as a "chain-of-custody" document. Each time the hazardous chemical changes hands, the responsible person signs the paperwork. At crucial stages copies of the paperwork may be sent to the appropriate government agency. (Of course, tbe bureaucratic implications of such a procedure are ominous.)

Importation of Regulation. The most disturbing hazards are those presented by potentially large-scale release of acutely toxic ohemicals, such as occurred in Bhopal, India. An obvious

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question of risk assessment is how i t can assist in preventing such ocour renee3 in the future.

Probabilistic risk analysis (PRA), discussed in the section on "Environmental Pathway Evaluation", page 35, is attractive for obtaining some idea of the risk represented by infrequent accidents with high consequences in the chemical process industry (CPI). To do so, however, requires access to comprehensive and systematic CPI databases that can be used to complete event and fault trees. Only recently such databases have become available in developed countries such as the United States (Mosieh et a l . 1986). Concerted efforts w i l l be needed to collect the relevant CPI data in developing countries. To help guide this effort, i t i s possible to identify the most c r i t i c a l data to be gathered f i r s t by using PRAs in an inverted manner. In the meatlme, however, i t would be necessary to rely on studies done of similar f a c i l i t i e s in the developed world.

This leads to an important recommendation. When f ac i l i t i e s with potential for large-scale accidents because of their inventory of toxic chemicals or for other reasons are proposed, developing countries may wish to specify safety and control equipment of the same type now required in developed countries for similar f a c i l i t i e s . This practice w i l l allow for more rea l is t ic probabilistic risk analyses, because the available database can be adapted. Further, the developing country can take advantage of the ongoing regulatory act ivi t ies in the developed country where such f ac i l i t i e s originated. Even so, differences in operation and maintenance may cause component r e l i a b i l i t i e s in developing countries to differ from the experience in technologically mature societies.

It would cot be wise, according to this logic, to allow an entirely new type of fac i l i ty to be f i r s t built in a developing country where regulatory and monitoring systems are s t i l l being developed. Better to build the same type and, i f possible, scale of f ac i l i t y as now exists in a developed country and rely on an informal import of regulation to bolster local regulatory

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ef for t s . Two other indus t r ies with potent ia l for large

accidents, a i r l i n e s and nuolear power, t r a d i t i o n a l l y r e ly on t h i s

method.

Thus, i n the short term, control over large-scale accidents

would be sought through appl ica t ion of the best avai lable

technology, not only i n the f a c i l i t y i t s e l f , but also for r i sk

analysis and regula t ion . Over time, as l o c a l expertise grows,

the extent of l oca l contributions w i l l r i s e .

T r i a l Risk Assessments. The par t ic ipants agreed that r i s k assessment, while requir ing modification for use under developing country condit ions, offered enough potential benefits to be pursued further . Only by conducting a t r i a l r i sk assessment under rea l conditions could the problems and prospects be f u l l y understood. Several p o s s i b i l i t i e s were mentioned as candidates for such t r i a l s : ( D a heavy metal contamination i n Indonesia, (2) a comparative assessment of new land f i l l s i n Malaysia and China, (3) a comparative assessment of pesticides i n Thailand, and (4) a study of comparative disposal options for PCBs i n Taiwan.

Differences East and West: Context and Perspective

Where does the hazardous chemical problem f i t i n the environmental and publ ic health issues facing developing countries? Resources of money and trained personnel are inadequate to the many concurrent tasks, and choices must be made. In many developing countries, malnutr i t ion, diarrhea, and respira tory diseases claim many more l i v e s than exposure to tox ic chemicals. Immunization programs are often the leas t -cost method of saving l i v e s . Carcinogens may not seem as important as other hazards where longevity i s only about 50 years because cancers generally have long latency periods. Economic growth and

80

improvement i n per capita GNP are strongly correlated with improved heal th ; thus, a r e s t r i c t i o n on useful chemical technologies may be contra- indicated.

On tbe other hand, decisions about chemical imports, s i t i n g , and choices among technologies are constantly being made. Often, options for development are e s sen t i a l ly equally a t t r ac t i ve , one of which may have far more severe chemical r i s k s than another. And some r i s k s , such as groundwater contamination, are long l a s t i n g and may cause damages Judged to be r e l a t i v e l y high and s ign i f i can t at a future date. I f chemical r i sk assessment i s reasonable i n time and cost, decision-makers should have i t s benefits now.

Even before i n d u s t r i a l i z a t i o n occurs, land and water sustain widespread contamination from agr i cu l tu ra l chemicals and so remedial ac t ion i s warranted—risk assessment can ident i fy problems and suggest cost-effect ive approaches and help set p r i o r i t i e s and timetables. Catastrophies such as Bhopal get much a t tent ion from o f f i c i a l s and the pub l ic , although they are rare . The more subtle effects from low-level emissions should be of concern too, and r i s k assessment can put these threats into perspective. Opportunities for choosing "clean" indust r ies and technologies can be revealed by r i s k assessment.

To a substant ial degree, the costs of r i sk assessment can be imposed on tbe purveyors and proponents of chemicals and chemical technologies as a requirement for permits. But an adequate indigenous capab i l i ty must be b u i l t by each nation i n order to require , review, and Implement r i sk assessments, even those undertaken by outside groups.

This Implies that r i sk w i l l be perceived and acted upon d i f f e ren t ly i n countries at various leve ls of economic development. That such differences exis t seems obvious, although i t should be remembered that most of the evidence i s anecdotal. To separate out the effects of cul ture i s d i f f i c u l t , however (Douglas and Wildavsky 1982). Although some attempts at c ross -cu l tura l r i sk assessment have been made, there i s c l e a r l y

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room for more work (Velimirovic 1975; Wright et al. 1978; Thompson.1980; Chllds 1984). There will also be important international differences because the presently poor countries are developing in an entirely different historical context (i.e., in a world where developed countries already exist). Cross-national historical comparisons may also provide valuable Insights (Clark 1980; Covello and Humpower 1985).

The "guidelines" in this report are to assist a variety of developing country officials and development professionals in arranging for and using risk assessments. Tbe guidelines should equip these persons to ask better questions of developers and to prepare Terms of Reference for contracting specialists in risk assessment.

APPENDICES

APPENDIX A

Databases

A database i s a compilation of information i n a comprehensive, organized, and consistent manner. A very useful resource for databases i n the r i s k assessment f i e l d i s the Risk Assessment Information Directory (prepared by ICF Inc. for the USEPA Office of So l id Waste and Emergency Response i n September 1986), which l i s t s the charac te r i s t i cs of several dozen databases and other information sources and ins t ruct ions about how to acquire them. For a discussion of the avai lable databases used i n p robab i l i s t i c r i sk analysis of chemical f a c i l i t i e s , see Mosleh et a l . (1986). For a bibliography on r i sk management i n developing countries, see the Annexes to UNCTAD (1987).

T r a d i t i o n a l l y , databases have been produced i n "hard-copy" (on paper), a good example being A Carcinogen Potency Database by Gold et a l . (NIEHS, USDHHS (NU084-218; also published i n Environmental Health Perspectives (58):9-319 f 1984). In recent years, however, most databases have been stored on computer f i l e s , which f a c i l i t a t e r e t r i eva l by subject matter using key words. Unt i l recently, accessing databases usually required a personal computer and a modem to transfer data over telephone l i n e s . It has also been possible, but more time-consuming, to query some databases by mail or to have the database off ice pr int out the information and mail i t back. In th i s way, telephone costs can be kept down.

Increasingly ava i lab le , however, i s the option of obtaining the database for manipulation without resor t ing to a communication l i n k . Ent i re databases can be put on one or a few "CD-ROMs," which means "compact disks—read only memory." A personal computer equipped with a disk dr iver and software can read compact d isks , which are about the same s ize as a 5-1/4 inch floppy but are capable of holding large amounts of data. Most of the computerized databases are becoming avai lable on CDs from

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commercial suppl ie rs , along with software for access from

personal computers.

As a s t a r t , some of the databases that would be useful to an

environmental planner working with hazardous chemicals are l i s t e d

i n Table A-1 at the end of th i s appendix. Some of the most

important organizations involved i n chemical r i sk databases are

b r i e f l y discussed below.

National Library of Medicine (NLM) Medical Li tera ture Analysis and Ret r ieva l System (MEDLARS)

The MEDLARS system i s one of the most comprehensive databases avai lable and i s used throughout the world by physicians, s c i e n t i s t s , planners, and engineers. The system can be accessed d i r e c t l y over telephone l ines or by CDs from l icensed private f i rms. A var ie ty of inexpensive software programs can be used to es tabl i sh contact with the NLM computer and to download data. Several of the databases avai lable through MEDLARS are:

• CANCERLIT (CANCER LITerature) i s sponsored by the National Cancer Ins t i tu te (NCI) and contains about 500,000 references dealing with various aspects of cancer. Since 1983, most journal c i t a t ions have been derived from MEDLINE. NCI contractors continue to input references from approximately 200 addi t ional foreign language Journals as wel l as from selected monographs, meeting abstracts , government reports, and theses. A l l reoords from non-MEDLINE sources contain abstracts . Records added since January 1980 have been indexed using Medical Subject Headings (MESH).

• CHEMLINE (CHEMical dict ionary onLINE) i s a f i l e of some 1 m i l l i o n names for chemical substances, representing 600,000 unique compounds. CHEMLINE, created by NLM i n

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col labora t ion with Chemical Abstracts Service (CAS),

contains such information as CAS reg i s t ry numbers,

molecular formulas, preferred chemical nomenclature, and

generic and t r i v i a l names. The f i l e may be searched by

any of these elements and also by nomenclature fragments,

making chemical structure searches possible .

HSDB (Hazardous Substances Data Bank) i s a s c i e n t i f i c a l l y reviewed and edited databank containing tox i co log i ca l information augmented by data i n environmental fate and exposure, standards and regulat ions, monitoring and ana lys is , and safety and handling.

MEDLEARN i s a computer-assisted ins t ruc t ion program that teaches the novice user how to search the NLM online system. Track A of MEDLEARN l a current ly avai lable and i s designed to teach the user to perform basic MEDLINE searches. The program provides onl ine , in te rac t ive ins t ruc t ions including simulated subject searches and a f i n a l quiz programmed to evaluate the user 's understanding of the material presented. Addi t ional tracks are under development, which w i l l provide user education for other databases and more advanced search techniques and system c a p a b i l i t i e s .

MEDLINE (MEDLARS onLINE) contains approximately 600,000 references to biomedical journal a r t i c l e s published i n tbe current and two preceding years. An English abstract , i f published with the a r t i c l e , i s frequently included. The a r t i c l e s are from 3,000 journals published i n the United States and 70 foreign countries; MEDLINE also includes a l imi ted number of chapters and a r t i c l e s from selected monographs. Coverage of previous periods (back to 1966) i s provided by backfi les that to t a l some 2.7 m i l l i o n references. MEDLINE i s updated monthly and

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i s used to publish Index Medicus and other recurr ing

bibl iographies .

RTECS (Registry of Toxic Effects of Chemical Substances), formerly the Toxic Substances L i s t , i s an annual compilation prepared by the National Ins t i tu te for Occupational Safety and Health (NIOSH). RTECS contains t o x i c i t y data for approximately 78,000 substances. Threshold l i m i t values, recommended standards i n a i r , and aquatic t o x i c i t y data are also included i n th i s f i l e .

TDB (Toxicology Data Bank) contains chemical, pharmacological, and tox ico log ica l information and data on approximately 4,000 substances. Information on addi t ional substances i s being prepared. Data for the TDB are extracted from handbooks and textbooks and reviewed by subject s p e c i a l i s t s .

TOXLINE (TOXlcology information onLINE) i s a c o l l e c t i o n of about 1.4 mil l ion-references from 1965 on published human and animal t o x i c i t y studies, effects of environmental chemicals and pol lutants , and adverse drug react ions. Older material (800,000 of these references) i s i n the two T0XBACK f i l e s . Almost a l l references i n TOXLINE have abstracts or indexing terms, and most chemical compounds mentioned i n TOXLINE are further i d e n t i f i e d with Chemical Abstracts Service Registry Numbers. The references are from nine major published secondary sources and f ive specia l l i t e r a tu r e co l l ec t ions maintained by other organizations.

TOXNET i s a f u l l y integrated software system offer ing the fo l lowing f i l e s : Hazardous Substances Data Bank (HSDB), Toxicology Data Bank (TDB), and INTR0T0X.

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International Register of Po t e n t i a l l y Toxic Chemicals (IRPTC) of the Pnlted Nations Environment Pr»np;n*nnne (UMEP)

This organization and i t s a f f i l i a t e a c t i v i t i e s , INFOTERRA (International Referral System for Sources of Environmental Information) and ECDIN (Environmental Chemicals Data and Information Network), make data on chemicals readily available to the international community, ide n t i f y potential hazards, encourage research to f i l l information needs, and provide l i s t s of consultants and national correspondents. The IRPTC maintains data p r o f i l e s on toxic chemicals and has also created smaller f i l e s dealing with regulations and waste management. These databases are b r i e f l y described below.

• Data P r o f i l e s on the health and environmental effects of toxic chemicals exist for approximately 600 major chemicals, half of which are used i n agriculture. IRPTC's policy i s to store only information that f a c i l i t a t e s tbe assessment of.chemical r i s k to the environment and to humans. New data p r o f i l e s are created and existing ones updated as new information becomes available.

• IRPTC1s Legal F i l e contains information on the regulatory status and administration of more than 5,000 chemicals. The data are drawn from countries that produce the chemicals as well as those that have banned or placed r e s t r i c t i o n s on them. The f i l e also provides information on national and international recommendations r e l a t i n g to tbe control of chemicals i n the environment and i n food, drinking water, consumer goods, and waste.

• The Waste Management F i l e provides information on recommended methods for disposing of waste chemicals, excluding i n d u s t r i a l processing wastes. I t s objective i s

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to help find ways of disposing of chemicals i n a pure state or i n product form.

In addition to i t s computerized databases, the IRPTC publishes the IRPTC B u l l e t i n and the Sentinel. The B u l l e t i n disseminates the results of chemical evaluations and the l a t e s t information on l e g i s l a t i o n and chemical safety, makes accident reports, and informs readers of new chemical hazards. The Sentinel i s a newsletter j o i n t l y sponsored by the IRPTC, the Environmental Hazards and Food Protection Unit of WHO, and the International Programme on Chemical Safety (IPCS). It covers the epidemiological and environmental assessment a c t i v i t i e s of the three organizations.

The IRPTC also generates the International Registry of Chemicals Currently Being Tested for Toxic Effects, a semiannual computer printout of data on long-term and/or expensive toxi c o l o g i c a l studies. I t does not survey chemicals being tested for cancer-causing properties.

U.S. Environmental Protection Agency (USEPA) Databases

Tbe USEPA has created more than 50 databases i d e n t i f i e d as being p a r t i c u l a r l y useful i n performing r i s k assessments. Most of these databases are part of an agency-wide compilation of databases, models, and information systems known as the "Information Systems Directory." Only a select few of these databases are described here. (The information for t h i s section was drawn from the Risk Assessment Information Directory, which provides an exhaustive l i s t of USEPA database resources.)

• The Acute Hazards Data database, which was developed following the Bhopal tragedy, i s concerned with the acute t o x i c i t y of various chemical substances that, i f released to tbe environment, would be of particular concern.

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EPACASR or CASR (EPA Chemical A c t i v i t i e s Status Report) contains more than 19,000 references to over 8,000 chemical substances reviewed or under review by the EPA in i t s regulatory a c t i v i t i e s and research. A summary of EPA a c t i v i t i e s i s provided with each named substance.

EEFIS (Environmental Effects/Fate Information System) provides information on chemical fate and environmental effects for selected chemicals. The database also contains information sources including Journal a r t i c l e s , tables, and unpublished EPA documents.

GEMS (Graphical Exposure Modeling System) enables rapid access to eleven environmental fate and transport models designed to assess the risks of hazardous chemicals from waste s i t e s migrating through various environmental media.

IRIS (.Integrated .Risk Information System) contains results of carcinogenic bioassays, dose-related responses, t o x i c i t y l e v e l s , reference doses, and other parameters used to control exposure. The system i s organized on a chemical basis and enables the user to c a l l up one of about 200 chemicals by name and review a l l the pertinent material that i s available.

PDMS (Pesticide Document Management System) contains s c i e n t i f i c data on pesticides including chemical contents, t o x i c i t i e s , and pertinent studies. These data were required to be' submitted to EPA by pesticide manufacturers before a pesticide product i s allowed to be manufactured i n the United States.

SPHERE ( S c i e n t i f i c Parameters for Health and the Environment, .Retrieval and Estimation) i s a comprehensive

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database drawn from tbe published l i t e r a t u r e containing f i v e data f i l e s on the health and environmental effects of chemicals. The Aquatic Information Retrieval Database (AQUIRE) provides information on the acute, chronic, bioaccumulatlve, and sublethal effects of more than 2,500 chemicals on freshwater and marine organisms. Dermal Absorption Database contains Information on the qua l i t a t i v e and quantitative health effects of about 650 chemical substances administered to humans and test animals through the skin. ENVIROFATE contains information on the environmental fate or behavior of chemicals released to the environment (biodegradation, oxidation, hydrolysis, water s o l u b i l i t y ) . Chemicals selected for inclusion are produced i n quantities exceeding 1 m i l l i o n pounds per year. GENETOX contains mutagenicity information on 3,170 chemicals that were tested against 36 bi o l o g i c a l systems. The Information System for Hazardous Organlcs i n Water (ISHOW) l i s t s the melting point, b o i l i n g point, p a r t i t i o n c o e f f i c i e n t , water s o l u b i l i t y , and similar types of information for more than 5,400 chemicals.

National Teohnical Information Service (NTIS)

The NTIS i s tbe central source for disseminating U.S. government-sponsored research and covers an enormous range of subjects, including environmental pollution, toxicology, r i s k assessment, and environmental health. Major corporations, trade associations, and university and private research i n s t i t u t i o n s also contribute their results to NTIS, making i t a comprehensive resource. The database consists of more than 1 m i l l i o n records dating from 1964.

The NTIS database i s bibliographic, meaning that i t generates l i s t s of c i t a t i o n s , each of which includes the

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researcher's or author's name, sponsor, r e t r i e v a l number, and, In most cases, a summary of the research. A search of the environmental pollution database on asbestos from 1983 to the present, for example, would y i e l d an extensive l i s t i n g of U.S. and some foreign research on asbestos as i t relates to p o l l u t i o n for the years specified. Many searches on important topics have already been made and are available i n published form. The cost of obtaining these i s much less than that of i n i t i a t i n g a. new search. After a search has been conducted, or a published search has been received, documents that seem p a r t i c u l a r l y useful may be ordered from NTIS.

NTIS also publishes an Abstract Newsletter on a number of subjects, including environmental pollution and control. This weekly newsletter summarizes research reports that have been recently received by NTIS, keeping the reader informed of current developments and providing rapid access to them.

Commercial Databases

In addition to those maintained by government and international agencies, a large number of databases have been compiled and are available from private companies. Some of these companies reorganized data o r i g i n a l l y generated by the USEPA i n th e i r exposure testing programs. A description of many of these commercial databases and information on how they may be accessed are contained i n the Risk Assessment Information Directory.

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Table A-1 Databases: A short l i s t

Source Subjeot Where maintained

EPA-NTfl Chemical Information System

-Physical, chemical, and regula- National I n s t i * tory information about chemical tute of Health substances

International Reg­i s t e r of Potential­l y Toxic Chemicals

17 p r o f i l e s on obemicals; es­se n t i a l physical and chemioal properties; t o x i c i t y ; reported effeots on humans and labora­tory organisms, and tbe envi­ronment; safe and e f f e c t i v e use of chemicals

O.N. Environment Programme

Registry of Toxic Effeots of Chemical Substances

Toxic effects of chemicals, including aquatic t o x i c i t y r a t i n g , cancer reviews

National I n s t i ­tute for Occu­pational Safety and Health, Center f o r Disease Control

Chemical A o t i v i t y Status Report

L i s t s chemicals research, au­th o r i t y for research, purpose, and information contact

O f f i c e of Toxic Substances, OSEPA

Information Sys­tems Inventory

Includes more than 50 databases Id e n t i f i e d as having the primary purpose of r i s k assessment

Office of S o l i d Waste and Emer­gency Response, USEPA

Medical L i t e r a t u r e Analysis and Retrieval System

A comprehensive group of data- National bases on the biomedical and Library of to x i c o l o g i c a l l i t e r a t u r e Medicine

National Teohnical Information Service

A comprehensive bibliography of U.S. and some foreign researoh on a wide range of subjects

Department of Commerce

Source: Adapted from OTA (1983).

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These databases may be accessed by contacting the i n s t i t u t i o n s l i s t e d i n Table A-1 at the following addresses:

National Institute of Health 9000 Rockville Pike Be the3da, MD 20892 (301) 496*2433

IRPTC/UNEP Palais des Nations 1211 Geneva 10 Switzerland

National I n s t i t u t e for Occupational Safety and Health Center for Disease Control 1600 C l i f t o n Road, N.E. Atlanta, GA 30333 (404) 329-3771

Office of Toxic Substances U.S. Environmental Protection Agency 401 M. Street, S.W. Washington, D.C. 20460 (202) 382-3810

Office of Solid Waste and Emergency Response U.S. Environmental Protection Agency 401 M. Street, S.W. Washington, D.C. 20460 (202) 382-2201

National Library of Medicine 8600 Rockville Pike Bethesda, MD 20894 (301) 496-5511

National Technical Information Service Department of Commerce Springfield, VA 22161 (703) 487-4600

APPENDIX B Case Studies

To i l l u s t r a t e how the r i s k assessment guidelines can be applied, the participants considered case studies of three of the major classes of toxic chemicals: an organic pesticide, a heavy metal, and a chlorinated hydrocarbon. Although the conditions of each case study were chosen from actual situations within the region, the numerical data are not real but were generated by the participants to i l l u s t r a t e the method. Thus, the conclusions based on these data do not follow from an evaluation of an actual si t u a t i o n .

The case studies are quite varied, thus confirming that no standardized r i s k assessment formula i s possible. An innovative, systematic, thoughtful approach based on sound s c i e n t i f i c research procedure i s required.

Case Study No. 1: Risks of Paraquat Manufacture and Use

Paraquat i s a cheap and effective bipyridilium herbicide used commonly i n agr i c u l t u r a l practices i n developing countries. Although the scenario discussed here i s f i c t i t i o u s , i t represents a s i t u a t i o n faced by many countries of the region using large amounts of paraquat. T r a d i t i o n a l l y , paraquat i s imported i n f i n a l form for transportation to agric u l t u r a l areas; but as i n d u s t r i a l i z a t i o n progresses i n many countries, within-country formulation and/or manufacture i s becoming an important alternative due to the lower costs involved. Taiwan, for example, imports blpyridine for processing into paraquat. Alternatively, pyridine i s imported, converted into bipyridine, and eventually processed into paraquat, a quaternary ammonium s a l t . Converting bipyridine to paraquat does not pose a si g n i f i c a n t health ri s k to workers, but converting pyridine to

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bipyridine i s quite dangerous, causing a high percentage of oooupational skin cancers.

Paraquat, p a r t i c u l a r l y when v o l a t i l i z e d , i s toxic to humans. It i s capable of causing mortality through pathologic changes i n lung, l i v e r , and kidney, and lung injury occurs even when the paraquat has been absorbed through pathways other than breathing.

Policy Question. Most paraquat i s imported by developing countries, although some manufacturing takes place i n factories using old technology star t i n g with pyridine. Recommendations are needed to determine whether the r i s k of paraquat to the public and to the harbor f i s h i n g Industry can be reduced by encouraging safer manufacturing processes and replacing present imports. The following questions must be evaluated:

• What are the present sources of contamination from paraquat?

• What i s the present r i s k to human health and tbe seafood industry?

• Could these r i s k s be reduced s i g n i f i c a n t l y by stopping imports and building new factories? At what cost?

• What other options are available to reduce exposure to paraquat? At what cost?

Boundary Setting. In this scenario we consider public exposure and potential harm to the f i s h i n g industry from paraquat use and produotion i n an enclosed watershed with a population of 1 m i l l i o n . Paraquat i s used i n ag r i c u l t u r a l a c t i v i t i e s both i n the uplands and lowlands of the watershed. Fields are drained by streams, whioh flow into the major r i v e r of the watershed. The importation and manufacture of paraquat takes place i n a large c i t y located at the mouth of this r i v e r . The water supply of most people i n tbe c i t y i s drawn from wells fed from groundwater flowing beneath the ag r i c u l t u r a l areas. A small percentage of

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tbe population (1,000 people) l ive on tbe banks of tbe r iver, downstream from the formulation plants, and draw drinking water directly from the r iver .

In assessing risk to tbe population, occupational exposures of factory workers are not considered. Accidents at the manufacturing plant and at the harbor wharf, where imports are unloaded, are considered; but transportation accidents occurring while tbe substance is being moved from the wharf or tbe factory to the f ie ld (by way of the retailer) are not considered.

Hazard Accounting. A substantial risk of accidental sp i l l s exists in shipping paraquat into the harbor and unloading i t at the wharf. The degree of damage from such a s p i l l would depend upon the location of the aocldent in relation to primary shellfish beds and fish breeding grounds and would also depend on the flushing rate of the estuary. We assume that the flushing rate is slow and that any material spilled would quickly be distributed throughout tbe estuary. The probability of a shipping accident taking place could be calculated from the number of paraquat importing ships, international shipping records, and an estimate of the frequency and magnitude of spillage at the wharf. This information may be derived from dock records or insurance claim forms.

The effect that paraquat would have on fish is also dependent on the amount of small-sized particulates suspended in the estuary water. This load i s l ike ly to be much greater during periods of high flow. The flushing rate may also be higher during these periods. Paraquat w i l l quickly be removed from solution by being irreversibly adsorbed onto these particles and deposited In the sediments. These particles are considered to be unavailable to most organisms, but they may pose a significant risk to bottom feeders such as crustaceans, because these are among the most sensitive organisms to paraquat. Paraquat i s not very toxic to fish but oan indireotly result in fish death i f i t colleots in shallow regions of the estuary where there are large

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amounts of aquatic weeds. Low concentrations of paraquat w i l l k i l l the weeds, oreating a large oxygen demand on weed decomposers, subsequently depleting the water of oxygen and causing fish death.

The paraquat manufacturing plant i s occasionally expected to release chemicals directly into the r iver, exposing those who use river water for drinking. The total amount and frequency of releases may be estimated by surveying factory permits. The likelihood of these releases is high because of equipment age and lack of information concerning chemical hazards available to management.

Paraquat i s applied in an agricultural environment. More than 90 percent of the paraquat would be expected to be adsorbed on soi l particles. If land immediately adjacent to a stream is under cult ivation, paraquat sprayed on the f ie ld might drif t into the stream. This drif t would be exacerbated i f spraying i s done by air instead of by ground-based workers. Drift from spraying may also spread to adjacent fields where the paraquat could be ingested by wildl i fe or cattle and by humans eating these animals. Humans may also receive exposure from drif t on vegetable garden crops. Material migrating into streams could be absorbed by fish and in turn eaten by humans. In order for a human to receive a significant dose of paraquat, fruits and vegetables would have to be consumed immediately after being sprayed.

Exposure and Dose. Estimated releases into the environment from various steps in the paraquat flow cycle (see Figure B-1) are shown in Table B-1. Large reductions in releases from manufacturing plants, transportation accidents, and storage are expected with conversion from importation and old plant formulation to new manufacturing f a c i l i t i e s . These reductions are expected due to improvements in efficiency, management, reduction of storage time, use of newer containers, and tighter control over paraquat movement. Tbe large releases associated

Figure B-1. Hypothetical flow cycle and hazards for paraquat.

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Table B-1 Hypothetical releases to the environment under the existing import/manufacturing conditions and after replacement by new manufacturing f ac i l i t i e s (hypothetical)

Existing conditions: 8,000 t /yr import;

2,000 t/yr manufactured New f a c i l i t y :

10,000 t/yr manufactured

Step Release fraction

Total release (t/yr)

Release fraction

Total release (t/yr)

Release from formulation plant 0.01 20 0.0001 1

Transportation accidents 0.01 100 0.001 10

Storage 0.01 100 0.001 10

Use: Air Water Land

0.01 0.01 0.01

100 100 100

0.001 0.001 0.001

100 100 100

with use would remain tbe same. The estimates of risk given below have been calculated under worst-case conditions. An improvement in tbe assessment would be to treat uncertainty expl ic i t ly by providing probability densities for expected effects and thus avoiding a worst case that may be unrealistic.

Hazards from Routine Operation. Batch releases occurring once a month from the old f ac i l i t y would endanger tbe water supply of the 1,000 people l iv ing along the river bank. River flows draining a watershed of 100 km by 100 km receiving ra infa l l of 2 m/yr would have an average overland flow of 5x10^ t/da. Half of the time the river is expected to be in a high flow condition of 5x10' t/da, and the other half in a low flow of 5x10^ t/da. One-day releases, containing 1.5 tons, occurring during low flow times would result in a concentration to 5X10~2

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5x10 - 8 5x10"7 5x10-5 SxlO"2

Lifetime dose (mg/kg/day)

Figure B-2. Hypothetical probability of tumors as a function of paraquat dose concentration (extrapolated values from high dose animal exposures).

•Probability of cancer = 95$ upper confidence limit for test animal (mg/kg/da)

Assumptions: Interspecies extrapolation factor of 5.8; daily dose converted according to mg/kg/da; and number of days exposed is 25,550 (70 yrs).

in water consumed .by the riverside community or a risk of '1 cancer per 100 individuals, a risk of 10 (see Figure B-2). During high flow periods the dilution is 100 times greater and, due to the large sediment loads in the river, 90 percent of the released paraquat would be removed from the solution rapidly, resulting in water containing 5x10*^ ppm, a cancer risk of approximately 10""*. Concentrations resulting from a 1-day batch release from the new manufacturing plants would be 1/20th as large, or 2.5xl0~^ ppm during high flow and 2.5x10"^ during low flow, resulting in more than 1 order of magnitude fewer cancers, with similar reductions in the likelihood of fish k i l l s .

Hazards from Accidents. Accidents in importing are most l ike ly to occur during high flow periods with significant likelihood of particulate adsorption of paraquat. An expected exposure to 0.01 ppm for one day would result from a single major

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episode releasing 100 tons Into the estuary. While fish death would s t i l l not be l ike ly , shellfish exposure from localized sedimentation of the paraquat would destroy a section of the industry. The problem would not persist, however.

Hazards from Agricultural Practices. An application level of 0.5 lb/acre would be expected to result in a dose of 3x10"^ mg/kg/hr from dermal and inhalation exposure of an agricultural worker applying paraquat with a backpack sprayer. Exposures of workers were assumed to occur for 1 hr/da, 3 days per week for 6 weeks annually for 15 years, resulting in a total worker dose

-5 -5 of 9x10 J mg/kg/da and a cancer risk of 2x10 . The 1,000 nearby residents would be expected to consume food that has accidentally received paraquat through dr i f t . This dose would result in a cancer risk of approximately 10 or 1 cancer per 10 mil l ion individuals. Toxic effects from consumption of paraquat-contaminated food would be unlikely because of i t s low levels (Table B-2). The greatest risk, 10"^f would be expected from moderate consumption of fish caught from nearby streams.

A major danger associated with paraquat use is the contamination of groundwater from land application. Given 100 t /yr escaping from soi l retention to groundwater under a worst-case scenario and given 10 1 0 tons of water moving through the drainage system under an assumption of total mixing, the concentration in the groundwater and subsequently the drinking

-8 water system of the city would be 10" tons paraquat/t water or

_2 0.01 ppm, an individual cancer risk of 10 in 70 years.

Table B-2 l i s t s expected concentration residues and doses on land plants, land animals, and aquatic organisms exposed either directly or indirectly (by runoff) to paraquat applied to upland agricultural f ields. A comparison of these values to the le thal-dose values l isted suggests that even under the assumptions of a worst-case direct exposure, the concentration would not result in loss of animal or plant l i f e .

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Table B-2 Doses and standards for paraquat

Organism Likely dose1 Worst-case dose1 EPA LD__ (ppm) (ppm) allowable

Land plants Forage Leaf forage Frui t

0.21 0.22 0.009

1.5 1.6 0.06

5.00 0.05 0.05

Land animals Cow Deer Bird egg Rabbit House

0.07 0.2 1.7 1.0 6.9

1.8 2.1 8.3 7.8

34.7

0.01 0.01

10 10. 25 10 *3.5

Aquatic l i f e Drinking water Stream trout Reservoir

blue gu l l Crayfish Isopoda

0.016 0.018

0.002 0.016 0.018

0.13 0.13

0.0026 0.13 0.13

0.06 29

13-400 1.U-39

12-2.6

Human food Lettuce Cow Rabbit Fish Water

0.03 0.0008 0.01 0.0006 0.0007

0.37 0.018 0.078 0.001 0.005

Humans Allowable Oral dose Inhalation Cancer (95* level/da)

0.00U 0.0003 0.01-0.1 0.035

From a scenario using an application of 0.5 lbs/acre to 80 acres adjacent to a stream and a garden without s o i l adsorption. In the worst-case scenario, runoff goes d i rec t ly into stream without attenuation.

Source: U.S. Department of Justice (1986).

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Table B-3 Alternatives to paraquat use for weed control

Alternative Comments

Glyphosate

2,4-D

Other herbicides

Biological control agent

Burning weeds

T i l l under weeds

Application rate high

Application rate high

Insufficient knowledge of effects

Not currently available; might spread to adjacent areas

Particulate exposure; runaway fires

Increased erosion potential; increased fuel usage

Alternatives. Other options, which would reduce many of the risks mentioned above but which would create new hazards, are available (Table B-3). For example, one alternative is tbe Import and substitution of glyphosate or 2,4-D for paraquat in agricultural use. These chemicals would have the same danger of shipping or wharf accidental s p i l l during the importing process but would reduce the manufacturing releases. Glyphosate is also readily adsorbed in soi ls or in aquatic sediments, whereas 2,4-D is somewhat more mobile. However, 2,4-D is rapidly hydrolized to acid in aquatic systems, and then degraded by microorganisms, particularly in warm, nutrient-rich waters. The short-term lethal doses for a l l three chemicals are similar: 1 to 15 ppm. However, tbe surfactant, which usually carries glyphosate, tends to be more toxic than glyphosate i t se l f . The application rate of the chemicals differs: paraquat at 0.5 lb/acre, glyphosate at 1.5 lbs/acre, and 2,4-D at 2.85 lbs/acre. The application rate alone is favorable for paraquat use since i t i s effective at lower concentrations.

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Table B-4. Hypothetical risks from paraquat options

Import with No import, some manufacturing new manufacturing

Population at risk

Number of individuals Risk Cancer Risk Cancer

Riverside dwellers 1,000 ID"2 10 i o - 5 <1

General public 1,000,000 10-* 100 io-" 100

Residents near fields 10,000 ID" 8 <1 1 0 - 8 <1

Agricultural workers 1,000 ID" 5 <1 10"5 <1

Risk Characterization and Management. Table B-4 shows tbe relative paraquat cancer risks for various populations associated with the two policy options. The greatest individual risk i s to river dwellers from batch releases (10 ). This risk could be substantially reduced by conversion to new manufacturing

-5 f ac i l i t i e s (10 ). The greatest number of adverse health effects are l ike ly to come from groundwater contamination (100 cancers). Consequently, the total risk to tbe population could only be reduced from approximately 110 cancers to 100 with conversion from importing to new manufacturing. The risk to tbe fish and shellfish industry, however, could be substantially reduced by conversion. In a l l likelihood tbe release to groundwater is overestimated by at least 1 order of magnitude. This would reduce the danger from groundwater contamination to a level where the total risk to the public (approximately 10 cancers) could be substantially reduced (to 1 cancer) by replacing imports with manufacturing. Public expenditure of money to encourage this change could also greatly reduce tbe risk of damage to the shellfish industry by shipping accidents. Therefore, i t i s c r i t i c a l l y important to estimate carefully the amount of paraquat moving from agricultural fields into the groundwater.

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The f i r s t order of business, however, would be to establish a monitoring system to evaluate carefully the losses of paraquat to groundwater.

Case Study No. 2: Cadmium Contamination of a Tropical River

The site is a provincial capital of 250,000 people, which has grown from 25,000 in just 15 years and is continuing to expand rapidly. It i s located on a large river (M) at the point of entry of a smaller river (K), which divides the city in two. Rapid growth has overwhelmed planning efforts and has led to indiscriminate si t ing of many small industrial f ac i l i t i e s and unplanned human settlements along the K River. These people use river water for a l l purposes, including drinking. Recently the cadmium (Cd) concentration in the river has reached levels 3 to 5 times that recommended for drinking water.

There are more than 1,000 factories in the c i ty , including the following types thought to be possible sources of Cd releases: electroplating shops, plastics factories, nickel (Ni) and Cd battery manufacturers, paint and dye factories, and wood glue factories. In addition, phosphate fe r t i l i ze r containing Cd i s used on a large agricultural area upstream along the K River. Cd levels are acceptably low farther upstream of the agricultural area. Because of geographic isolation from other areas, nearly a l l fresh food is produced local ly .

Polloy Question. Recommendations are needed for short- and long-term ways to mitigate the risks of Cd contamination to the population. A multilateral bank is wi l l ing to support a risk management effort i f the risk assessment reveals effective solutions. The decision must be made in 6 months.

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Boundary S e t t i n g . T h i s i n i t i a l study w i l l focus on p u b l i c exposures w i t h i n the area nearest the K R i v e r i n which about 10,000 people o b t a i n t h e i r d r i n k i n g water d i r e c t l y from the r i v e r . Outside t h i s a r e a , d r i n k i n g water comes from numerous s m a l l w e l l s . Not i n c l u d e d are o c c u p a t i o n a l exposures and p o s s i b l e l a r g e r e l e a s e s from a c c i d e n t s i n the f a c t o r i e s or t r a n s p o r t systems w i t h i n the watershed.

W i t h i n these boundaries, t h e r e f o r e , the f o l l o w i n g q u e s t i o n s are addressed:

Which sources are most l i k e l y to be the c h i e f p o l l u t e r s ? What are the p r i n c i p a l routes of exposure to the p o p u l a t i o n ? What are the l i k e l y h e a l t h e f f e c t s ? What are the o p t i o n s f o r c o n t r o l ? How can these be compared?

Please note t h a t the data presented below and the c o n c l u s i o n s r e s t i n g upon them represent h y p o t h e t i c a l c o n d i t i o n s d e r i v e d by the working group. They are used here t o i l l u s t r a t e the method. To d e s c r i b e the true s i t u a t i o n would r e q u i r e a c t u a l o n - s i t e measurements. (Much of the i n f o r m a t i o n on Cd was taken from the IRPTC B u l l e t i n , C r i t e r i a (Dose/Effect R e l a t i o n s h i p s ) f o r Cadmium by the Commission of the European Communities 1978, and E v a l u a t i o n Methods f o r Environmental Standards by Rowe 1983.)

Hazard Accounting. The f a c t o r i e s can be i n v e n t o r i e d a c c o r d i n g t o permits f i l e d a n n u a l l y w i t h the government. They can then be l o c a t e d on the map i n r e l a t i o n t o the r i v e r and the t a r g e t p o p u l a t i o n . The Department of A g r i c u l t u r e has e s t i m a t e s of crop area and the amount of f e r t i l i z e r a p p l i e d a n n u a l l y .

Based on t h i s i n v e n t o r y , a t a b l e of e f f l u e n t d i s c h a r g e s i s c r e a t e d (see Table B-5), which i s confined t o sources upstream from the t a r g e t area. The major e f f l u e n t s f o r each i n d u s t r y are determined as best as p o s s i b l e by a.combination of e f f o r t s :

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Table B-5 Hypothetical emission assessment using r e l a t i v e hazard index i n l i t e r s per day d i l u t i o n needed to bring r i v e r water to standard

^ ^ ^ o l l u t a n t

Source

Release f r a c t i o n Cd Pb Solvent Others

Total HI

Electro­plating

100 10 5 10* e t c . 1 „ 1 etc. 1.1x105

Battery 100 10 4 10* 2X101*

Paint manu­facturing

100 10* - i o 4

F e r t i l i z e r 100 ii 2x10 - 2x10 U

Total RHI 1 .ilx10 5t ll 2x10 I — 1.6x10 5l

Emissions (mg) _ l i t e r s of d i l u t i o n with water Standard mg/l " required to meet standard

Calculated i n a s i m i l a r fashion

• A "walkdown" t o check on the rough accuracy of f i l e d p ermits.

• Reference t o pub l i s h e d generic emission values (e.g., WHO 1982).

• Random samples taken from e f f l u e n t o u t f a l l s s t r a t i f i e d by type, s i z e , and prevalence of i n d u s t r i a l f a c i l i t i e s . Samples are a l s o taken t o l e a r n the Cd content of the f e r t i l i z e r , which i s mined l o c a l l y .

For the i n i t i a l hazard assessment, i t i s assumed that 100 percent of the l i q u i d and s e m i l i q u i d discharges reach the r i v e r . From Table B-5, t h e r e f o r e , i t i s p o s s i b l e t o g a i n a rough i d e a of which i n d u s t r i e s r e l e a s e the most Cd. In a d d i t i o n , tbe l i s t i n g w i l l g i v e an i d e a of ot h e r p o l l u t a n t s a l s o being r e l e a s e d . A cross-check w i t h r i v e r c o n c e n t r a t i o n s f o r those p o l l u t a n t s w i l l g i v e an i d e a of the t r u e r e l a t i v e r e l e a s e r a t e s . F u r t h e r , i t

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w i l l help c o n f i r m that Cd i s indeed the p o l l u t a n t of most concern i n t h i s s i t u a t i o n . For determination of which i n d u s t r i a l c l a s s accounts f o r tbe most p o l l u t i o n , c o n s i d e r i n g a l l types of p o l l u t i o n , we use the r e l a t i v e hazard index (RHI). The RHI i s simply a measure of how much water would be needed to d i l u t e the r e l e a s e of chemicals t o the l e v e l equal to the d r i n k i n g water standard.

Exposure and Dose. Table B-5 i n d i c a t e s that e l e c t r o p l a t i n g f a c i l i t i e s probably account f o r the g r e a t e s t r e l e a s e of Cd t o the r i v e r , but t h a t an a p p r e c i a b l e amount may a l s o be coming from a p p l i c a t i o n of f e r t i l i z e r . In order to determine the r e l a t i v e importance of these sources, however, an assessment of t o t a l exposure i s necessary. T h i s i s p a r t i c u l a r l y important f o r Cd because l i t e r a t u r e i n d i c a t e s that food, not water, i s u s u a l l y the most s i g n i f i c a n t exposure route (Hutchinson and Meema 1937).

Consequently, f o r a t o t a l exposure assessment, i t i s decided to conduct a survey of the Cd content of l o c a l food and ambient a i r . The food sampling i s done on a market-basket b a s i s and i s d i v i d e d by age and sex as shown i n Table B-6. The r e s u l t s are estimates of t o t a l d a i l y i n t a k e . Standard values from the l i t e r a t u r e are used f o r weighting the r e l a t i v e c o n t r i b u t i o n s of swallowed and i n h a l e d Cd (6 and 16 percent a b s o r p t i o n , r e s p e c t i v e l y ) .

F i n d i n g s r e v e a l a d u l t men are the most exposed group, even i g n o r i n g a probable s i g n i f i c a n t a d d i t i o n from c i g a r e t t e smoking. T h e i r exposure i s about seven times the recommended t o t a l i n t a k e and d i s t r i b u t e d among the d i f f e r e n t exposure routes as shown i n Table B-6. Food, not water, dominates the exposures (Bennett 1981).

By conducting b i o l o g i c a l m o n i t o r i n g (e.g., measuring Cd l e v e l s i n body f l u i d s ) , attempts t o v e r i f y these exposure estimates would be p o s s i b l e . However, the high exposure estimates (even though based on only a few measurements) j u s t i f y

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Table B-6 H y p o t h e t i c a l assessment of d a i l y Intake of cadmium f o r men, women, c h i l d r e n , and i n f a n t s

? C h i l d I n f a n t ug/da

D r i n k i n g water a 1 a 2 a 3 aH 100

Food

Rice b 1 b 2 b 3 b U 200

Vegetable °1 °2 C 3 °« 100

F i s h d 1 d 2 d 3 dH 50

A i r e 1 e 2 e 3 e4 50

500

s k i p p i n g t h i s expensive and time-consuming step i n t h i s f i r s t and l i m i t e d assessment.

Hea l t h E f f e o t s . Using published dose-response i n f o r m a t i o n f o r Cd summarized i n F i g u r e B-3, the r i s k s of these p r o j e c t e d exposures are shown i n Table B-7. A l s o shown are the p o p u l a t i o n r i s k s and expected " n a t u r a l " i n c i d e n c e r a t e s of cancer m o r t a l i t y and kidney disease f o r t h i s p o p u l a t i o n . These values are based on l i f e t i m e exposures f o r prostate tumors and 1-year exposures f o r kidney d i s e a s e . Since p o p u l a t i o n and i n d u s t r i a l i z a t i o n have been growing r a p i d l y , however, exposures have not been constant. I t i s t h e r e f o r e u n l i k e l y t hat any cancers have a c t u a l l y yet appeared from Cd exposures (Rowe 1933).

Risk C h a r a c t e r i z a t i o n . Four c o n t r o l measures were i d e n t i f i e d (see Table B-8). They were compared based on t o t a l p o s s i b l e exposure r e d u c t i o n , cost per u n i t r e d u c t i o n , and s e v e r a l

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100T

Noncarcinogenic

Cd concentration in drinking water in ppm over one year

10-3T

Possibility of human prostate cancer

3 30 300 3000

Cd concentration in drinking water in ppb over lifetime (70 years)

F i g u r e B-3- H y p o t h e t i c a l dose-response curves f o r cadmium.

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Table B-7 H y p o t h e t i c a l h e a l t h e f f e o t s per year from cadmium exposure

I n d i v i d u a l P o p u l a t i o n N a t u r a l

Excess cancer r i s k io-« 1 10

Excess kidney disease 10- 3 10 5

Table B-6 Comparison among various hypothetical control measures

>v Faotor Tears Cost Job Regula­

Option Total effect

to f u l l extent Op front

Per unit exposure

replace­ment

tory costs

Eoo-systen

Status quo 0 - - - - 0 _

Ban f e r t i l i z e r

-300 5 0 $H0,0O0/yr •

Substitute f e r t i l i s e r

-300 5 • t2,000/yr 0 •

Substitute food

-100 1 0 190,000/yr 0 0

Lower worker -10 exposure

Symbols; +, ++, +++ = Growing importance of impact in this category 0 e L i t t l e Impact - c Hot appropriate

1 Dnit of exposure used here equals 100 ug/de for entire.population

o t h e r c h a r a c t e r i s t i c s . Since the a l t e r n a t i v e s take d i f f e r e n t amounts of time t o produce r e s u l t s , i t was decided that time l i n e s would be v a l u a b l e f o r comparison. Figure B-4 presents a comparison of the time p a t t e r n s f o r two o p t i o n s ( s u b s t i t u t i n g

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3

500

400

300 +

CD (0

J. 200 to Q

100

Action Time

F i g u r e B-4. Temporal comparison of two h y p o t h e t i c a l c o n t r o l o p t i o n s f o r reducing cadmium exposure.

food and s u b s t i t u t i n g f e r t i l i z e r ) . Note that the food o p t i o n g i v e s a b e t t e r r e s u l t In the short run, but l e s s i n the long run.

I t was decided t o check the e f f e c t i v e n e s s of the c o n t r o l measures a g a i n s t other o p t i o n s f o r l o w e r i n g Cd exposures. Based on the number and type of l o c a l i n d u s t r i e s , f o r example, i t was determined t h a t a sma l l number of people (-100) were r e c e i v i n g f a i r l y l a r g e d a i l y i n t a k e s , but that o c c u p a t i o n a l exposures d i d not add a p p r e c i a b l y (<10 percent) t o t o t a l p o p u l a t i o n exposures.

By widening the system boundary even f u r t h e r , a comparison of r i s k r e d u c t i o n i n human h e a l t h can be made w i t h the c o s t -e f f e c t i v e n e s s of a l o c a l immunization program ( - $ 1 0 0 / l i f e saved), T h i s provides one s o r t of b a s e l i n e f o r e v a l u a t i n g the cost of r i s k r e d u c t i o n of other s o r t s .

116

R i s k Management. Based on tbe r i s k assessment and economic a n a l y s i s , i t was decided t o conduct f o u r a c t i v i t i e s i n the f o l l o w i n g order of p r i o r i t y :

1. Immediately s e t up a m o n i t o r i n g and enforcement system f o r banning those l o c a l foods ( c e r t a i n vegetables) w i t h the h i g h e s t c o n t r i b u t i o n s to exposures. Arrange f o r s h i p p i n g of s u b s t i t u t e s . M o n i t o r i n g and ban to continue u n t i l Cd l e v e l s f a l l .

2. Stop a p p l i c a t i o n of high-Cd f e r t i l i z e r . Seek a l t e r n a t i v e sources (guano d e p o s i t s ) . F a l l i n g t h i s , e s t a b l i s h f e r t i l i z e r treatment p l a n t s .

3. Seek low-cost means to reduce o c c u p a t i o n a l exposures. 4. Over midterm, e v a l u a t e means to reduce Cd waste

discharge i n the r i v e r .

Case Study No. 3: P o l v c h l o r i n a t e d B i p h e n y l Wastes

In t h i s s c e n a r i o , the import of PCBs has been banned and the f u r t h e r use of PCBs r e s t r i c t e d to c l o s e d systems, such as e l e c t r i c a l transformers and c a p a c i t o r s a l r e a d y i n o p e r a t i o n . A l t e r n a t i v e d i e l e c t r i c f l u i d s are to be used i n new c a p a c i t o r s and t r a n s f o r m e r s . A survey of i n d u s t r i a l wastes i n d i c a t e s 1,000 tons of PCB wastes are i n storage and that about 5,000 tons are s t i l l being used i n c a p a c i t o r s and transformers u n t i l these devices are phased out d u r i n g the next 5 years. PCBs i n storage a r e h e l d i n drums under cover i n b u i l d i n g s w i t h s l o p i n g f l o o r s t o r e t a i n any s p i l l s or leakages from c o r r o d i n g or damaged drums. Leaking drums a r e enclosed i n p l a s t i c , but some PCBs may v o l a t i l i z e and be emitted to tbe environment. A number of these storage s i t e s are owned by p r i v a t e i n d u s t r y .

An environmental survey i n d i c a t e s that the average PCB c o n c e n t r a t i o n i n g r a i n s and f i s h ranges from 10 t o 100 ppb. The

117

eggs of a f i s h s p e c i e s c a l l e d m u l l e t t c o n t a i n about 2 ppm approximating tbe USFDA standard of 2 ppm PCB f o r e d i b l e p a r t s , suggesting no cause f o r concern.

Samples of human adipose t i s s u e obtained d u r i n g surgery c o n t a i n 1.4 and 1.0 ppm of PCBs f o r men and women, r e s p e c t i v e l y , I n samples from l e s s than 30 I n d i v i d u a l s f o r each sex.

Legal r e g u l a t i o n s c o v e r i n g the use and d i s p o s a l of PCBs s t a t e that they are hazardous wastes and should be disposed of ac c o r d i n g t o r e g u l a t i o n s , i n s t r u c t i o n s , and standards; however, these are s t i l l being d r a f t e d . As PCBs are t o x i c chemicals, t h e i r manufacture, import, s a l e , exchange, and usage should be reported before any a c t i o n i s taken. R e t r o f i t t i n g of transformers c o n t a i n i n g PCBs i s p r o h i b i t e d .

Problems Concerning PCB Management and D i s p o s a l (Hazard I d e n t i f i c a t i o n ) . About 5,000 tons of a d d i t i o n a l PCB wastes w i l l be generated as c a p a c i t o r s and transformers c u r r e n t l y i n use are d i s c a r d e d . Problems a s s o c i a t e d w i t h the safe storage of waste PCBs w i l l i n t e n s i f y year-by-year as storage drums corrode and develop l e a k s .

As t h e r e i s no a p p r o p r i a t e high-temperature hazardous waste i n c i n e r a t o r , the country does not wish t o r i s k a i r p o l l u t i o n problems a s s o c i a t e d w i t h inadequate i n c i n e r a t i o n , p a r t i c u l a r l y d i o x i n and dibenzofuran p o l l u t i o n .

The government has t o decide whether or not to continue to s t o r e PCB wastes u n t i l an economic and environmentally safe d i s p o s a l technology has been developed to t r e a t such wastes. F a i l i n g t h a t , a d e c i s i o n must be made as t o what technology f o r d i s p o s a l of hazardous PCB wastes should be adopted t o t r e a t the 6,000 tons of PCBs that w i l l accumulate d u r i n g the next 5 y e a r s .

P o s s i b l e S o l u t i o n s . Four p o s s i b l e management o p t i o n s f o r the 6,000 tons of PCB wastes t o be generated are c o n s i d e r e d , as shown i n F i g u r e B-5. In each case, the best p o s s i b l e technology would be used to safeguard workers and the environment and t o

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In use 5,000 t)

Recovery and transport

(1) Store (currently 1,000 t; rising to 6,000 t)

/ (2) Local incineration

Transport

, ^ • (4) Overseas incineration (3) Ocean incineration

F i g u r e B-5. H y p o t h e t i c a l PCB management o p t i o n s .

reduce the l i k e l i h o o d of s p i l l s or a c c i d e n t s . The four o p t i o n s considered a r e :

1. Storage f o r up t o 10 years. 2. B u i l d a l o c a l high-temperature hazardous waste

i n c i n e r a t o r t h a t would begin o p e r a t i o n i n 1992. 3. Negotiate a c o n t r a c t t o have the PCB wastes i n c i n e r a t e d

on an ocean-going i n c i n e r a t o r v e s s e l . 4. Negotiate a c o n t r a c t to have the PCB wastes exported

overseas f o r I n c i n e r a t i o n .

Boundary S e t t i n g . The boundaries are d i c t a t e d by f o c u s i n g on the r i s k s of PCB l o s s e s to tbe environment and the I m p l i c a t i o n s of these l o s s e s f o r human exposure. Although mean

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leve ls of PCBs i n human t issues are avai lable from the l i t e r a t u r e , tbe effects of long-term, low-dose exposures to PCBs In humans are not well known. Acute or toxic effects can be considered where there i s more information on response. An a l ternat ive to health effects information could be an a r b i t r a r i l y set l i m i t on how much increase i n PCB body burdens i n exposed groups w i l l be to lera ted.

The amount of the various PCB isomers (molecular var ia t ions) i n the 6,000 tons of waste w i l l have to be determined since th i s w i l l influence uptake, body burden, and potential health effects .

The r i s k assessment w i l l be concerned with minimizing further human exposure as evidenced by addit ional increases i n body burden. It w i l l include primari ly occupational groups that must c o l l e c t , transport, and dispose of the PCBs, and populations that might be exposed through these a c t i v i t i e s including the famil ies of workers.

Es tab l i sh System of Chemical Flow Patterns (Hazard Accounting). In order to determine the chemical flow pattern for storage, a number of questions have to be answered regarding the loca t ion of the PCBs at any point i n time, how they w i l l be col lec ted and transported, and the i d e n t i f i c a t i o n of a l l potent ia l hazards associated with th i s a c t i v i t y .

The PCBs s t i l l In use (5,000 tons) w i l l have to be located and transported, e i ther i n the i r o r ig ina l containers ( i . e . , transformers) or removed to metal drums. Removal from transformers i s associated with greater exposure through inha la t ion of v o l a t i l i z e d PCBs and dermal contact. The exact amounts of these exposures may be d i f f i c u l t to determine.

The l i k e l i h o o d that not a l l PCB-containlng equipment w i l l be Ident i f ied and how many might be missed should be considered. Other concerns include how much loss w i l l occur i f the PCBs are removed from the i r o r ig ina l containers to metal drums, and whether the workers who must remove the PCBs w i l l be exposed. Studies have shown that workers i n plants that manufacture or use

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PCBs have higher body burden l eve l s compared to ind iv idua l s i n other occupations. This suggests that body burden l eve l s of PCBs i n exposed workers should be determined before t h i s a c t i v i t y begins. Ident i fying the population that w i l l be c o l l e c t i n g and transporting the PCBs w i l l therefore be important.

Regardless of the management option chosen, storage of PCBs for some undetermined period w i l l be necessary. The period of storage and the amount of PCBs to be stored for each option should be estimated. Given the amount put into storage and the storage time, t h i s question a r i ses : How much PCB can be expected to be los t at storage s i tes? Also of concern i s how much of the l o s t PCBs w i l l v o l a t i l i z e , contaminate the s o i l or ground including roadway, or contaminate surface waters, groundwater, and marine waters.

Preliminary Risk Character izat ion. This step requires assessing the four possible management options described e a r l i e r .

A comparison of r i sk s should be made for each opt ion. The assessment should estimate the l i k e l i h o o d of a l l possible exposures to human populations (occupational and community) and to the environment. For example, the assessment of l o c a l inc inera t ion would require:

• Accident l i k e l i h o o d during transport from storage to the inc inera tor .

• Accidental releases from the inc inera tor . • Incinerator malfunction or incomplete i nc ine ra t i on .

• Risk to workers during normal operation of inc inera tor . • Risk to community given incinerator loca t ion and

operation.

For export or ocean inc inera t ion , r i s k assessment of accidental releases during loading and transport i n the harbor w i l l have to be developed. An estimate of the potent ia l damage to the harbor and marine environment from PCBs can be derived

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from data on PCB contamination i n other aquatic systems and the

bioaccumulation data that already e x i s t . A comparison of the different r i s k s should ident i fy which

management a l ternat ive demonstrates the least r i sk to the environment and to the community. These r i s k estimates should be presented i n table and/or graphic form. Each a l ternat ive w i l l have a r i s k of f a i l u r e . The next step i s to estimate the s izes of the spec i f ic populations that would receive exposures i f the a l ternat ives f a l l . Costs of each a l ternat ive can then be used to calcula te cost-effectiveness i n reducing r i s k s .

Dose Response and Health Effects . In order to estimate dose responses or health effects , a to ta l exposure assessment to PCBs i s necessary. This requires determining the potent ia l t o t a l exposure to PCBs from the a i r ( e . g . , indoor, outdoor, workplace), water ( including PCBs v o l a t i l i z e d from water and inhaled) , and spec i f i c foods. Calculated amounts of PCBs from ambient exposure and from exposure due to a given management a l ternat ive can then be added to obtain the to t a l exposure.

We can assume that the greatest exposure potent ia l w i l l occur among the occupational groups of adult men who would be exposed due to v o l a t i l i z a t i o n , accidental s p i l l s , or f i r e s . The route of exposure would be by inhala t ion and through the s k i n .

For human health effects , the current l eve l s of PCBs In the groups that w i l l be po ten t ia l ly exposed should f i r s t be determined. This w i l l help assess how much addi t ional PCBs these groups may be able to tolerate without negative health effects . Most studies have shown that the major route of ambient PCB exposure i s through food. To confirm t h i s , l eve l s of PCBs i n the a i r and dr inking water are determined i n a market-basket survey. Current l eve l s i n a i r samples taken at l oca l storage s i t es and from drinking water samples w i l l probably be i n the parts per t r i l l i o n range, Just above the l eve l of detection. Food l eve l s w i l l most l i k e l y be i n the ppb range and considerably higher than i n a i r and water combined. Tbe highest food l eve l s are t y p i c a l l y

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found i n f i s h . This has impl ica t ions for those a l te rna t ives that

include shipping PCBs.

Risk Management. Exporting PCBs resu l t s i n the reduction of occupational exposures to a l eve l corresponding to the r i s k from storage and transport associated with a l l the a l t e rna t ives . Local incinerat ion 'would resu l t i n roughly the same occupational exposure (more ind iv idua l s but short-pterm exposures of 6 months) as long-term storage (fewer ind iv idua ls but long-term exposures), and both have roughly equal r i sk s to the community and the environment.

The cost of exporting PCBs i s about four times .higher than storage (see Table B-9)* Local inc inera t ion i s more than .twice as cos t ly . The problem of how to choose among these a l te rna t ives can be eased by .obtaining better estimates of the number of workers that w i l l .be exposed under different management a l ternat ives and whether or not workers tin the e l e c t r i c a l industry already have higher body burden l eve l s than the general population. Body-burden i n these workers, nevertheless, should be monitored. ;

The r e l a t i ve costs of each of the.four options were estimated, bearing Mn mind that the basic cost of inc ine ra t ion would be s i m i l a r i n each of the-three inc inera t ion .options but would incur addi t ional handling, transport, and insurance costs i n the ocean and overseas options. (In 1983 the cost of inc inera t ing toxic- hazardous wastes i n the United States ranged •< from $400-to $800 per ton.)

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Table B-9- Hypothetical coat estimates for PCB management

Option Cost

1. Storage capacity for 6,000 t

Capital works $5 m1

Operation and maintenance $1 m / y r

Total for 5 years $10 m

Total for 10 years $15 m

2. Local inc inera t ion Capi ta l works (rotary k i l n ) $10 to 15 m

Operations $2,000/t Total for 6000 t $12 m Total disposal cost $22-27 m

Disposal plus storage for 5 years $32-37 m

3. Ocean inc inera t ion

Disposal charge $8,000/t Total for 6,000 t 2 $48 m

Disposal plus storage for 5 years $58 m

4. Overseas inc inera t ion Charge for acceptance $16,000/t

Total for 6,000 t $96 m Disposal plus storage for 5 years $106 m

m = m i l l i o n 2 Only l i q u i d wastes are acceptable for ocean inc ine ra t ion ; thus,

PCBs would have to be taken out of tbe transformers, whereas land incinerators could handle the metal containers as w e l l .

APPENDIX C

L i s t of Par t ic ipants

Mr. Richard A. CARPENTER Research Associate Environment and Pol icy Ins t i tu te East-West Center 1777 East-West Road Honolulu, Hawaii 96648 T e l : (808) 944-7269

Dr. Yeong-Ren CHEN D i v i s i o n Chief Toxic Substances Regulation

D i v i s i o n Bureau of Environmental

Protect ion Executive Yuan Ta ipe i , Taiwan, China T e l : 7150800

Mr. CHENG Boxing Engineer Chinese Research Academy of

Environmental Sciences Beiyuan, B e i j i n g , China T e l : 46.1025

Dr. Richard CIRILLO Adjunct Research Associate Environment and Po l i cy Ins t i tu te East-West Center 1777 East-West Road Honolulu, Hawaii 96848 T e l : (808) 944-7229

Ms. Susanne FAULSTICH Research Assis tant Environment and Po l i cy Ins t i tu te East-West Center 1777 East-Vest Road Honolulu, Hawaii 96848 T e l : (808) 944-7244

Dr. Loren J . HABEGGER Manager Physical Environmental Sciences

Section Energy and Environmental

Systems D i v i s i o n Argonne National Laboratory 9700 South Cass Avenue Argonne, I l l i n o i s 60439 T e l : (312) 972-3761

Dr. Joel S. HIRSCHH0RN Senior Associate Industry, Technology and

Employment Program Office of Technology Assessment U.S. Congress Washington, D.C. 20510 T e l : (202) 226-2089

Dr. Nay HTUN Regional Director and

Representative for As i a and the P a c i f i c

United Nations Environment Programme

United Nations Bu i ld ing Rajadamnern Avenue Bangkok 10200, Thailand T e l : 2829161-200, 2829381-3&9

Ms. Rosnanl IBARAHIM P r i n c i p a l Assis tant Director Department of Environment 13th F loor , Wisma Slme Darby Jalan Raja Laut 50662 Kuala Lumpur, Malaysia T e l : 03-2938955

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126

Ms. H a i t i 100KG Researcher Energy and Mining Research

Service Organization No. 4, Lane 190 Nan-Eung Road, Section 3 Ta ipe i , Taiwan, China T e l : 02-7833231

Dr. F . DeUolfe MILLER Department of Public Health

Sciences School of Publ ic Health Univers i ty of Hawaii at Manoa I960 East-West Road Honolulu, Hawaii 96822 T e l : (808) 948-8894

Mr. Wayne MITTER Consultant Environment and Pol icy

Ins t i tu te East-West Center 1777 East-West Road Honolulu, Hawaii 96848 T e l : (808) 944-7239

Dr. Haluk OZKAYNAK Project Manager and

Research Fellow Energy and Environmental

Pol icy Center Harvard Univers i ty 65 Withrop Street Cambridge, Massachusetts

02138 T e l : (617) 495-1313

Dr. Dhira PHANTUMVANIT Associate Director Natural Resources and

Environment Programme Thailand Development

Research Ins t i tu te Rajapark Bu i ld ing 163 Asoke Road Bangkok 10110, Thailand T e l : 258-9012-17, 258-9027-29

Dr. K i rk R. SMITH Research Associate Environment and Pol icy

Ins t i tu te East-West Center 1777 East-West Road Honolulu, Hawaii 96846 T e l : (806) 944-7519

Dr. Roebajat E . SOERIAATHADJA Assistant Minis te r Minis t ry of State for

Population and Environment

Jalan Herdeka Barat 15 Jakarta , Indonesia T e l : 021-374371

Dr. John S. WATD Professor Department of Microbiology La Trobe Univers i ty Bundoora V i c t o r i a 3083 Aus t r a l i a T e l : 03-478-3122

Dr. David A. WE IN STEIN Staf f Sc i en t i s t Ecosystems Research Center Cornel l Univers i ty 323 Corson Ha l l Ithaca, New York 14853 T e l : (607) 255-3435

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Part-time Par t ic ipants

Dr. Saleem AHMED Research Associate Resource Systems Ins t i tu te East-West Center 1777 East-West Road Honolulu, Hawaii 96648 T e l : (808) 944-7553

Dr. Bruce S. ANDERSON Environmental Epidemiologist

Consultant Department of Health P.O. Box 3378 Honolulu, Hawaii 96801 T e l : (808) 548-2076

Mr. Michael BAHM Steams-Roger 700 South Ash Street P.O. Box 5888 Denver, Colorado 80217 T e l : (303) 692-2122

Dr. Raymond BOYKIN Pickard, Lowe & Garr ick , Inc. 2260 Univers i ty Drive Newport Beach, CA 92660 T e l : (714) 650-8000

Mr. James I . COLLINS Vice-President , Administrat ion Ind u s t r i a l Innova11o ns, Inc. P.O. Box 830 Stockton, C a l i f o r n i a 95201 T e l : (209) 462-8241

Mr. George DIALS Direotor Internat ional Studies Energy and Environmental

Systems D i v i s i o n Argonne National Laboratory 9700 South Cass Avenue Argonne, I l l i n o i s 60439-4815 T e l : (312) 972-3778

Ms. Susan FERNANDES Senior Program Manager Radian Corporation 8501 Mo-Pac Boulevard P.O. Box 9948 Aust in , Texas 78766-0948 T e l : (512) 454-4797

Mr. Gary GALIDA Senior Executive Consultant NUS Corporation 910 Clopper Road Gaitbersburg, Maryland 20878 T e l : (301) 258-6000

Dr. Jake HAL LTD AY Manager Industr ia l and Internat ional

Business Development B a t t e l l e , Columbus D i v i s i o n 505 King Avenue Columbus, Ohio 43201 T e l : (614) 424-6424

Mr. Monro B. LANIER I I Vice-President USX Engineers and Consultants,

Inc. 600 Grant Street Pit tsburgh, Pennsylvania 15230 T e l : (412) 433-6538

Dr. Stephen LAU Director Water Resources Research Center 2540 Dole S t . Holmes H a l l 283 Honolulu, Hawaii 96822 T e l : (808) 948-7847

Mr. David MONROE Manager Environment Products Unocal Corporation 1201 W. 5th Street P.O. Box 7600 Los Angeles, C a l i f o r n i a 90051 T e l : (213) 977-7983

128

Mr. Cesar1 NAD ALA * Degree Student Environment and Po l i cy

Ins t i tu t e East-West Center 1777 East-West Road , Honolulu, Hawaii 96848 T e l : (808) 948-8055

Mr. David NELSON !

President EnvlroSearch 608 E. Wilmington Avenue Sal t Lake C i t y , Utah 84106 Tel,: (801) 466-1035

Dr. Chai Bin PARK Research Associate, Population Ins t i tu te East-West Center 1777 East-West Road Honolulu, Hawaii 96848 T e l : (808) 944-7458

Mr. Sam PINTZ. Research Associate Resource Systems. Ins t i tu te East-West Center 1777. East-West Road Honolulu, Hawaii 96848 T e l : (808) 944-7552

Dr. Surya S. PRASAD Senior Scient is t , and' Project

Manager Dames & Moore 7101 Wisconsin Avenue,

Sui te 700 • '. Bethesda, Maryland 20814-4870 T e l : (301) 652-2215 .

Dr. K i l a p a r t i RAMAKRISHNA Fellow Environment and Po l i cy

Ins t i tu te .East-West Center 1777 East-West Road. Honolulu, Hawaii 96848 T e l : (808) 944-7258

Dr. Norman F.SATHER Deputy Director Energy and Environmental

Systems D i v i s i o n

Argonne National Laboratory 9700 South Cass Avenue, EES-362 Argonne, I l l i n o i s 60439 T e l : (312); 972-3724

Ms. Helene TAKEMOTO Environmental. Resources Section U.S. Army Corps of Engineers Pac i f i c Ocean D i v i s i o n Bldg. T-1 F t . Shatter, Hawaii 96858-5440 T e l : (808) 438-2263

Mr. Richard TEDESCHI Business Development Manager Northwest Environmental

Technology Center Westinghouse E l e c t r i c

Corporation 1545 George Washington Way Richland, Washington 99352 T e l : (509) 946-9774

Dr. George VANDER VELDE .. Vice-President , Chemical Waste Management, Inc. 150 West 137th Street Riverdale, I l l i n o i s 60627-T e l : (312) 841-8360

Dr. Lyle WONG Director ' Environmental ' A f f a i r s Dole Pineapple Co. P.O. Box. 3380 Honolulu, Hawaii 96801 T e l : (808) 536-3411

APPENDIX D

Condensed Agenda

Monday. July 6. 1987 Welcome (N. Glnsburg) Agenda-setting (R. Carpenter) Overview of Risk Assessment (K. Smith) Overview of Chemical Flows (D. Weinstein) Risk Assessment of Hazardous Chemicals (S. Prasad)

Tuesday. July 7 Developing Country Experiences and Concerns UNEP Views (Nay Htun) China (B. Cheng), Indonesia (B. Soeriaatmadja), Thailand (D. Phantumvanit), Taiwan (H. Loong), and Malaysia (R. Ibarahim)

Wednesday. July 8 P a c i f i c Islands (H. Takemoto) USX Methods (M. Lanier) Toxic Chemicals i n Hawaii Water Resources (B. Anderson and

S. Lau) F i e l d t r i p to Dole Pineapple f a c i l i t i e s (W. Mitter and

L. Wong)

Thursday. July 9 Unocal Methods (D. Monroe) Public Health (F. M i l l e r ) Ecotoxicology (D. Weinstein)

Friday. July 10 Hazard C l a s s i f i c a t i o n (L. Habegger) Hazardous Waste Management i n Australia ( J . Waid) EnviroSearch Methods (D. Nelson) Industrial Innovations, Inc., Methods ( J . C o l l i n s )

Monday. July 13 Hazardous Waste Reduction ( J . Hirschhorn) Mu l t i d i s c l p l l n a r y teams established to develop sample flow

patterns and r i s k assessments for specified chemicals

Tuesday. July 14 Use of Cyanide i n Gold-mining (S. Pintz) Westinghouse E l e c t r i c Methods (R. Tedeschi) Ba t t e l l e Methods (J. Halliday) Small groups continue work

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130

Wednesday. July 15 Radian Corp. Methods (S. Fernandes) Risk Analysis (R. Boykin) Carriage of Dangerous Goods by Sea (K. Ramakrishna) Small groups continue work

Thursday. July 16 Waste Surveys ( J . Hirschhorn) Stearns-Roger Methods (M. Bahm) Chemical Waste Management, Inc., Methods (G. Vander Velde) Reports of small groups i n plenary

Friday. July 17 Continue research on case studies Undertake study of a different chemical

Monday. July 20 Risk Assessment Methods (H. Ozkaynak) Plenary to review chemical flows Undertake ris k assessments

Tuesday. July 21 Plenary on r i s k assessment Presentation of case studies Continue work on chemical ris k assessment

Wednesday. July 22 NUS Corp. Methods (G. Gallda) Outline workshop report

Thursday. July 23 Review of r i s k assessment methods Refine case studies

Friday. July 24 Findings and recommendations for developing countries

Perception of r i s k Need for r i s k assessment Indigenous capability Status and trends i n chemicals use and manufacture

Adlourn

APPENDIX E

Papers Presented at tbe Workshop

Some Toxic Chemicals i n Hawaii Water Resources: Public Health and Risk Considerations, by Bruce S. Anderson

Risk Management and Risk Assessment for Chemical Operations, by Raymond F. Boykin

Risk Assessment of Hazardous Chemicals i n Developing Countries: Scope and Objectives of the Workshop, by Richard A. Carpenter

Management of Hazardous Materials and Wastes i n China, by Cheng Boxing

Management Strategies for Chromium-Containing Waste i n China, by Cheng Boxing

Selection of Appropriate Risk Assessment Procedures for Use i n Risk Management of Hazardous Chemicals, by Loren J. Habegger

Report on Toxic and Hazardous Wastes i n Malaysia, by Rosnani Ibrahim

Industry Wastes i n Taiwan, by H a i t i Loong

Potential for Risk Assessment i n Thailand, by Dhira Phantumvanit Method Selection for Qualitative Risk Assessment of Hazardous Chemicals, by Surya S. Prasad

Risk Assessment with Special Reference to Toxic Chemicals, by Kirk R. Smith

Hazardous Chemicals: Indonesian Concerns and Experiences, by R.E. Soeriaatmadja

Present and Future Development of Hazardous Waste Research i n Indonesia, by R.E. Soeriaatmadja

Toward an Ecosystem Risk Evaluation, by David A. Weinstein

131

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THE EAST-WEST CENTER is a public, nonprofit educational institution es­tablished in Hawaii in 1960 by the United States Congress. The Center's man­date is "to promote better relations and understanding among the nations of Asia, the Pacific, and the United States through cooperative study, train­ing, and research."

Some 2,000 research fellows, graduate students, and professionals in busi­ness and government each year work with the Center's international staff on major Asia-Pacific issues relating to population, resources and develop­ment, the environment, culture, and communication. Since 1960, more than 25,000 men and women from the region have participated in the Center's cooperative programs.

Principal funding for the Center comes from the U.S. Congress. Support also comes from more than 20 Asian and Pacific governments, as well as private agencies and corporations. The Center has an international board of governors. President Victor Hao Li came to the Center in 1981 after serv­ing as Shelton Professor of International Legal Studies at Stanford University.

THE EAST-WEST ENVIRONMENT AND POLICY INSTITUTE was estab­lished in October 1977 to increase understanding of tne interrelationships among policies designed to meet a broad range of societal needs over time and the natural resources on which these policies depend or which they affect. Through interdisciplinary and multinational programs of research and training, the Institute seeks to develop and apply concepts useful in iden­tifying alternatives available to decision-makers and assessing their impli­cations. Progress and results of Institute programs are disseminated in the East-West Center region through books-, occasional papers, working papers, newsletters, and other educational and informational materials.

Norton G'nsburg, Director Environment and Policy Institute

East -West Center 1777 East-West Road

Honolulu, Hawaii 96848