Studies in Environmental Science 24 DETERMINATION AND ASSESSMENT OF PESTICIDE EXPOSURE Proceedings of a Working Conference, Hershey, PA, October 29-31, 1980 ed it ed by Marie Siewierski Department of Environmental Science, Cook College, Rutgers State University of New Jersey, New Brunswick, NJ 08903, U.S.A. E LSEV I E R 1984 Amsterdam - Oxford - New York - Tokyo ELSEVIER SCIENCE PUBLISHERS B.V. Molenwerf 1 P.O. Box 21 1, 1000 AE Amsterdam, The Netherlands Distributors for the United States and Canada: ELSEVIER SCIENCE PUBLISHING COMPANY INC 52, Vanderbilt Avenue New York, NY 10017 ISBN 0-444-42416-4 (Vol. 24) ISBN 0-444-41696-X (Series) @Elsevier Science Publishers B.V., 1984 All rights reserved. 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Printed in The Netherlands VII Preface Though pesticides have a crucial and beneficial role in the management of organisms that destroy food and fiber or threaten public health, the deliberate distribution and use of pesticides can create environmental and health problems. There is increasing governmental concern and public interest regarding the pos- sible consequences of human exposure; therefore, the risks as well as the bene- fits must be assessed. Involved in the assessment of overall hazard to man from the use of pesticides is the acquisition of detailed information concerning human exposure. Exposure analyses play an important role in risk/benefit decisions, which attempt to evaluate the health impact on man by the quantifi- cation of exposure by oral, dermal, and inhalation routes resulting from pesti- cide use. The exposure groups include mixer/loaders, applicators, bystanders, home gardeners, and the general population. This symposium explored the problems concerning the determination and assess- ment of pesticide exposure. Papers focus on the techniques and analytical methodology in monitoring human exposure, the interpretation and use of exposure data, and descriptions of iiiethods for reducing pesticide exposure. The contents will be of interest to those in academia, regulatory agencies, and industries who are engaged in risk/benefit assessment of the use of pesticides. VIII ACKNOWLEDGEMEN1 I like to express my gratitude to Maureen Barge for the invalunhlc assistance she provided in editing and organizing the manuscript. P1.S. SPONSORS NJAES, Rutgers, The State University of New .Jersey U.S. Department of Agriculture U.S. Environmental Protection Agcncy 3 Y ARC 1A W T LLIM I S Speci 1 I’estic ides Kevirw Oivi siori, Envi ronnre>ntal I’rotc,c.t ion Ayencv , Washington, U.C. (U.S.A.) Wliat I hope' tliis conCerence can do in the next two and n liillf days is increase and the degree of uridcrstanding regarding pesticide exposurc assessment. What T’ll try and do in tlie next half hour is discuss the rille or exposure data in tlie Environmental Protection Agency’s (EPA) regulatory d~~cision- making on pesticides. All tlicsc derisions are risk/benefit decisions and exposure plays a key role in determining risk. My major rocus will covcr tlccisi~~n-rn~il\iiig for pesticides wliicli niiiy causc~u nreasilnahle advcrsc afft.ct.s. I will: --Ilescrihe the process - RPAR (Kebuttabl e Presumption Against RegistraLion) --c .i’ ve two case examples. 1 will then touch briefly on other regulatory decision areas which nrcd ex- posure data. --Reg i s t ra t i on --Registration Standards or Reregistration --Other Regulatory Restrictions (ON) Finally, I will close with some suggestions on positive directions for the future. Let me begin by describing the environment in which risk/benefit regulatory decisions on pesticides are made. These items are not necessarily related or presented in ony order. However, they provide a sense of the complexity of the decision-making process. --Individuals rarely know how much exposure they receive or the potential risk -- that they are under no informed decision is possible. --Often, individuals receive exposure without their expressed consent (on food, in the air, in the water) -- spray drift; (1) Scottsdale, (2) Gypsy Moth. --There are very few people who don’t benefit in some way from the use of pesti- cides (agriculture, disease control, home uses, forests). --Different groups reap the benefits than those that suffer the health/environ- mental risks; risks are suffered by the general population or applicators while benefits accrue to farmers and the pesticide industry. 4 --Imperfect methods of evaluating risk. --Evolving concepts on the environmental causes of cancer and other chronic dis- eases -- initiator vs. promotor concept. --Rapidly changing technology -- e.g., application methods such as water soluble packaging or electrostatic sprayers. --There is a trade-off between scientific certainty and timeliness of decisions. --Differences of opinion on the proper balance between risk and benefit. --Differences of opinion on the extent to which the government should intervene in cases where the risks and benefits are known and confined to a private citizen -- e.g., Strychnine poisoning. REBUTTABLE PRESUMPTION AGAINST REGISTRATION (RPAR) Introduction E.P.A.'s Rebuttable Presumption Against Registration (RPAR) Program is de- signed to: 1. quickly and comprehensively weigh risks and benefits of potentially hazardous pesticides 2. determine if regulatory action is necessary to protect the public and the environment. Stages of RPAR Review 1. Pre-WAR a. perform initial risk investigation b. perform intensive review and validation of key hazard studies c. inform registrants of review and ask them for additional data on hazards and exposure d. perform an extensive literature search to identify all possible triggers (areas of concern) e. if hazard studies are valid, start preliminary assessment of available exposure information to make sure a significant risk exists (section 3(c) (8) Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA) requirement The above information is used to produce the Agency's preliminary position on the potential risk of the pesticide and position document (PD 1) is published in the &&&. Reoists with the formal RPAR Notice. 2. Issuance of an RPAR u. a. The public process begins when PD 1 is published in the Eeder;ll (1) 45 days are provided for comment by the public (2) 60 day extention granted if justified (3) therefore, could have a 105 day period in which presumptions can be rebutted 5 b. How risks may be rebutted (1) prove that trigger studies are not scientifically valid (2) prove that actual exposure to compound will not cause effects described. c. At this point in the process the gathering of additional information takes place in the form of: (1) rebuttal comments (2) additional information on risk (3) input from other Agencies primarily: - United States Department of Agriculture (USDA), information on exposure and benefits - United States Department of Interior - Office of Endangered Species, information on implications of environmental trigger. d. IT all triggers rebutted successfully The pesticide is returned to the registration process and the RPAR ter- minates for all or some uses. PD 2 is published. e. When rebuttal is not successful then E.P.A. develops the following in order to prepare PD 2/3 (1) rebuttal assessment (2) risk analysis (including exposure assessment) (3) benefit analysis (4) risk/benefit synthesis (5) proposed regulatory position to cost effectively reduce the pesticide's risks. f. PD 2/3 is composed of (1) Introduction -- reviews the RPAR criteria giving rise to the RPAR on the pesticide in question (as presented in PD 1) (2) Risk Analysis -- presents the risk situation under status quo conditions of currently registered uses of the pesticides through synthesis of toxicity and exposure information (3) Benefit Analysis -- presents the impact that total cancellation of the pesticide would have - also examines on a use by use basis. (4) Analysis of Alternatives -- examines risks and benefits of alternatives for each use (5) Risk/Benefit Analysis -- presents regulatory options under consideration for each use, their risks, their benefits (6) Recommended Regulatory Position -- presents the Agency's rationale behind the choice of options g. Reviews of PD 2/3 (1) Assistant Administrator, Office of Pesticides and Toxic Substances (AA OPTS), approves the document at conclusion of risk/benefit analysis; Notice of Determination - published in the FederaJ keister (PD 2/3 is 6 now available to the public for review and comment). (2) Scientific Advisory Panel Review of scientific basis of propcised decision required by FIFRA. (They focus on exposure and hazard inrormation). (3) Secretary of Agriculture for comment. (Focus on exposure ,ind benefits). h. Evaluation of the Reviews on PD 2/3 Comments of Scientific Advisory Panel and U.S.D.A. plus industry or public . comments on proposed decision are evaluated. i. Publication of PD 4 The Agency assesses comments received on PD 2/3 and publishes its final regulatory decision in PD 4. 3. Hearings a. If "a person adversely affected by the Notice" objects to Agency's action they can request an administrative hearing under Section 6(b) of FIFRA. B. Further appeals can be taken to Court of Appeals, Section 16(b) of TITRA. ROLE OF EXPOSURE DATA IN THE RPAR PROCESS Introduction 1. During RPAR review we are interested in assessing the risk of a particular pesticide 2. Although it is toxicity data which triggers the Agency's concern, it is a combination of toxicity and exposure which determines risk. (Note the difference between threshhold and non-threshhold effects) 3. Exposure information allows us to determine the actual risk to the population from a toxic chemical. What is an RPAR Exposure Analysis? 1. An WAR exposure analysis looks at two areas concerning the chemical under RPAR review: a. What population is exposed? b. What are the pathways of exposure? 2. The analysis generates estimates of exposure to the following populations: a. Human (1) the general United States population (2) pesticide applicators (3) at times sub-populations can be important; example: specific geographic area such as the southeast United States where larger than average quantities of fish are consumed b. Fish and Wildlife (1) non-target population 3. The main pathways of exposure analyzed are dietary, inhalation, and dermal. a. Dietary is a concern of both the general and applicator populations, where 7 as, dermal and inhalational exposure are largely limited to applicators, various types of fieldworkers, or people in the vicinity of the application. b. 1-or non-target populations, the pathways of exposure are largely a function of the habitat of the affected species. For example, exposure to fish results because water becomes contaminated with pesticides. In contrast, exposure to terrestrial specics, while largely dietary, may also de dermal or inhalational depending upon the location of the animals during applica- t ion. 4. The exposure analysis attempts to ascertain what exposure levels exist for each exposure pathway. 5. Then, exposure estimates are calculated fur each population and these estimates form the basis of the risk estimate for the chemical. 6. Dr. David Severn who will follow my presentation will provide you with a more detailed explanation of the RPAR exposure analysis. ROLE OF EXPOSURE DATA IN RPAK Pre-RPAR Phase 1. Exposure information can he used to rebut a presumption of threshhold risk based on toxicity data. Example: closed systems result in minimal exposure and the threshhold is not exceeded. 2. The registrant would try to demonstrate that actual exposure to the pesticide will not result in unreasonable adverse effects to the environment. (for non-threshhold effects) Risk/Benefit Analysis 1. Exposure analysis plays a major role in assessing the risk of the pesticide. 2. Exposure analysis may input into comparative risks of alternatives, chemical and non-chemical. Regulatory Options 1. Regulatory options are the means by which we attempt to reduce the risk of the pesticide. 2. Exposure analysis is very important in our efforts to reduce risk by reducing exposure. 3. Exposure analysis and risk analysis are necessary for all potential regulatory options to determine which options are most appropriate. For example, res- pirator and protective clothing; water soluble containers; flagging devices; enclosed cabs; technological innovations to application technology - e.g., varying droplet size through nozzle adjustments; aerial application during low wind conditions; reformulations. 8 CASE EXAMPLES The following two examples illustrate the range of exposure data which can be available and the way in which that influences decisions. The first example had relatively good data and the second example had much weaker exposure data. DBCP -- A Soil Fumigant for Nematocide Control Hazards -- Cancer, Sperm affects Regulatory History -- Suspension of some uses in 1977, RPAR initiated in 1977, completed in 1978 (PD 2/3), another suspension in November 1979 based on new exposure data showing DBCP in drinking water. Administrative hearings are cur- rently on hold. 1. Available exposure data (as of 1978): a. Agency had actual company submitted residue data for food crops, including data which indicated that 19 vegetable crops were contaminated with DBCP after application. b. Agency also had applicator data including data on ambient air levels in treated areas as well as information which supported the conclusion that 100% of DBCP which penetrated protective clothing was absorbed. c. Agency had epidemiological data for pesticide producers in a California plant (both exposure and effects data). d. In response to an Emergency Suspension Order and concurrent RPAR, the state of California initiated applicator exposure studies and provided information not only on applicator exposure but also residue information on crops previously not believed to be contaminated with DBCP. California also developed an improved analytical technique for testing for food crop residues. e. California Department of Health Services also provided monitoring information which showed that DBCP was capable of leaking into groundwater and has been detected in groundwater around the Occidental plant. California State Department of Health and Agriculture provided data which demonstrated leaching of DBCP in groundwater in treated food crop areas. This resulted in E.P.A.'s sending people into the field in several states to sample groundwater. Additional information was provided by several states in which DBCP was routinely used. f. Additional exposure information was provided by registrants (at time in cooperation with California), the Pineapple Growers Association, and the Food and Drug Administration (FDA). California also developed information concerning various techniques, including protective clothing and closed mixing and loading systems designed to reduce exposure to an acceptable level. 2. Impact of availability of actual exposure data on DBCP regulatory decision a. Agency was able to minimize use of assumptions.