Dermal Exposure Related to Pesticide Use In Dermal Exposure Related to Pesticide Use; Honeycutt, R., et al.; ACS Symposium Series; American Chemical Society: Washington, DC, 1985. In Dermal Exposure Related to Pesticide Use; Honeycutt, R., et al.; ACS Symposium Series; American Chemical Society: Washington, DC, 1985. ACS SYMPOSIUM SERIES 273 Dermal Exposure Related to Pesticide Use Discussion of Risk Assessment Richard C. Honeycutt, CIBA-GEIGY Gunter Zweig, EDITOR University of California, Richmond Nancy N. Ragsdale, EDITOR Department of Agriculture Based on a symposium sponsored by the Division of Pesticide Chemistry at the 187th Meeting of the American Chemical Society, St. Louis, Missouri, April 8-13, 1984 American Chemical Society Washington, D.C. 1985 In Dermal Exposure Related to Pesticide Use; Honeycutt, R., et al.; ACS Symposium Series; American Chemical Society: Washington, DC, 1985. Library of Congress Cataloging in Publication Data Dermal exposure related to pesticide use. (ACS symposium series, ISSN 0097 6156; 273) Includes bibliographies and indexes. 1. Agricultural laborers—Diseases and hygiene— Congresses. 2. Pesticides—Toxicology—Congresses. 3. Skin—Permeability—Congresses. I. Honeycutt, Richard C., 1945- . II. Zweig, Gunter. III. Ragsdale, Nancy, 1938- . IV. American Chemical Society. Division of Pesticide Chemistry. V. American Chemical Society. Meetin Louis, Mo.) VI. Series. RC965.A5D47 1985 616.5 84-28361 ISBN 0-8412-0898-0 Copyright © 1985 American Chemical Society All Rights Reserved. The appearance of the code at the bottom of the first page of each chapter in this volume indicates the copyright owner's consent that reprographic copies of the chapter may be made for personal or internal use or for the personal or internal use of specific clients. This consent is given on the condition, however, that the copier pay the stated per copy fee through the Copyright Clearance Center, Inc., 21 Congress Street, Salem, MA 01970, for copying beyond that permitted by Sections 107 or 108 of the U.S. Copyright Law. This consent does not extend to copying or transmission by any means—graphic or electronic—for any other purpose, such as for general distribution, for advertising or promotional purposes, for creating a new collective work, for resale, or for information storage and retrieval systems. The copying fee for each chapter is indicated in the code at the bottom of the first page of the chapter. The citation of trade names and/or names of manufacturers in this publication is not to be construed as an endorsement or as approval by ACS of the commercial products or services referenced herein; nor should the mere reference herein to any drawing, specification, chemical process, or other data be regarded as a license or as a conveyance of any right or permission, to the holder, reader, or any other person or corporation, to manufacture, reproduce, use, or sell any patented invention or copyrighted work that may in any way be related thereto. Registered names, trademarks, etc., used in this publication, even without specific indication thereof, are not to be considered unprotected by law. PRINTED IN THE UNITED STATES OF AMERICA In Dermal Exposure Related to Pesticide Use; Honeycutt, R., et al.; ACS Symposium Series; American Chemical Society: Washington, DC, 1985. ACS Symposium Series M. Joan Comstock, Series Editor Advisory Robert Baker Robert Ory U.S. Geological Survey USDA, Southern Regional Research Center Martin L. Gorbaty Geoffrey D. Parfitt Exxon Research and Engineering Co. Carnegie-Mellon University Roland F. Hirsch James C. Randall U.S. Department of Energy Phillips Petroleum Company Herbert D. Kaesz Charles N. Satterfield University of California—Los Angeles Massachusetts Institute of Technology Rudolph J. Marcus W. D. Shults Office of Naval Research Oak Ridge National Laboratory Charles S. Tuesday Vincent D. McGinniss General Motors Research Laboratory Battelle Columbus Laboratories Douglas B. Walters Donald E. Moreland National Institute of USDA, Agricultural Research Service Environmental Health W. H. Norton C. Grant Willson J. T. Baker Chemical Company IBM Research Department In Dermal Exposure Related to Pesticide Use; Honeycutt, R., et al.; ACS Symposium Series; American Chemical Society: Washington, DC, 1985. FOREWORD The ACS SYMPOSIU medium for publishing symposia quickly in book form. The format of the Series parallels that of the continuing ADVANCES IN CHEMISTRY SERIES except that, in order to save time, the papers are not typeset but are reproduced as they are submitted by the authors in camera-ready form. Papers are reviewed under the supervision of the Editors with the assistance of the Series Advisory Board and are selected to maintain the integrity of the symposia; however, verbatim reproductions of previously pub lished papers are not accepted. Both reviews and reports of research are acceptable, because symposia may embrace both types of presentation. In Dermal Exposure Related to Pesticide Use; Honeycutt, R., et al.; ACS Symposium Series; American Chemical Society: Washington, DC, 1985. PREFACE IT IS GENERALLY RECOGNIZED that a potential health risk exists for agricultural workers (applicators, mixer-loaders, harvesters, and field workers) who are exposed to pesticides. Thus, since 1980, various symposia, including the one upon which this book is based, have been held to examine various parameters involved in the risk assessment of these workers due to dermal exposure from pesticides. Although an abundance of literature has been published on the assess ment of agricultural worker exposure, none integrates the three disciplines necessary for a complete pesticides. These disciplines are dermal absorption, field exposure studies, and toxicology-risk assessment. This volume deals with these three disci plines and shows how they are integrated into a complete risk assessment for agricultural workers from dermal exposure to pesticides. The book is divided into five sections, each dealing with specific topics of risk assessment. The first section deals with the most recent views on dermal absorption of chemicals through human skin and experimental methods and techniques on how to arrive at quantitative absorption data using animal models or in vitro systems. The diversity of methodology presented in this section reflects the quickly evolving state of the art in this field. The second and third sections are descriptions and results of field studies with emphasis on methodology and specific compounds or specific applicator sites. The fourth section deals with trends in exposure assessment and protection and reflects some of the more creative approaches and research dealing with predicting exposure and protecting workers against exposure. Chapters 25, 26, and 27 deal with predicting exposure levels for agricultural workers. Although such predictive techniques would be generally welcomed by regulators, industrial scientists, and academicians, the contradictory nature of some of the material in these three chapters reflects the current status of such research, i.e., the final answer on predictive techniques and a generic data base is not in yet. Much discussion is needed before moving from these first generation data bases to a common, functional, well-received second generation data base. Furthermore, section four is a discussion of mathematical models and the use of fluorescent tracers in conjunction with television imagery, tech niques that are seen by most researchers in the field to have the potential to replace older, more cumbersome, and less precise exposure evaluation xi In Dermal Exposure Related to Pesticide Use; Honeycutt, R., et al.; ACS Symposium Series; American Chemical Society: Washington, DC, 1985. techniques. The areas of the social impact of drift (unintentional exposure) and the use of protective clothing to eliminate exposure are addressed in this section, and they will be extremely important areas for exposure-risk- assessment research in the future. The last section is a discussion of the use of experimental data to arrive at risk assessment as recommended by states such as California, Canadian governmental regulatory agencies, and industry. These parties share a com mon goal, namely to make the workplace safe for agricultural workers who are exposed to pesticides through normal work activities. It is apparent from these last chapters that risk assessment for agricul tural workers from dermal exposure to pesticides is an extremely complex technique that is evolving rapidly and will require considerable future resources for it to be refined to a fine science. The editors of this volume, who were also the organizers of the symposium, want to than their time and experience, and who made this publication a valuable tool for scientists, administrators, and others charged with establishing rules and regulations for the safe use of pesticides. We would also like to thank our symposium session chairpersons, Joe Reinert (EPA), Rhoda Wang (CDFA), Tom Fuhremann (Monsanto), Richard Moraski (EPA), and James Adams (EPA) for their contributions in making this symposium a success. RICHARD C. HONEYCUTT CIBA-GEIGY GUNTER ZWEIG University of California, Richmond NANCY RAGSDALE Department of Agriculture November 1984 xii In Dermal Exposure Related to Pesticide Use; Honeycutt, R., et al.; ACS Symposium Series; American Chemical Society: Washington, DC, 1985. INTRODUCTION THE TWO BASIC DETERMINANTS of human health hazard for toxic chemi cals, including pesticides, are exposure (or dosage) and toxicity (or effect). Information on both these determinants of hazard is necessary in arriving at a risk assessment for a particular pesticide or pesticide usage. The exposure parameter is particularly important for agricultural workers because of their relatively greater contact with pesticides than is true for the general popu lation. A preponderance of past and current health-related research on pesti cide chemicals has emphasize ogy and reproductive effects, genotoxicity, including mutagenic and carcino genic effects, neurotoxicity, and other modalities of toxicity. Study of these effects undoubtedly represents a most important and necessary step in defining the human health hazard of these agents. However, in order to complete the risk assessment process, it is also necessary to have information on the exposure, or dosage, involved. Exposure to pesticides may occur through ingestion, by inhalation, and from skin contact. The major route of importance for the general population is through ingestion in food and water. Agricultural workers who have contact with pesticides in their occupation are exposed by the dermal and inhalation routes. Previous studies have shown that for most outdoor, field- type applications of pesticides dermal exposure is greater than respiratory exposure even when appropriate allowance is made for the greater speed and completeness of absorption by the inhalation pathway. Thus, the decision to target the symposium upon which this book is based to dermal exposure seems appropriate for agricultural workers. Two general types of methods are available for estimating human exposure to pesticides. First, direct entrapment methods involve the use of some mechanism to entrap the toxic material as it comes in contact with the person during an exposure period. The amount of entrapped toxicant, as determined by chemical analysis, is then a direct measure of the particular exposure under study. Further calculations using the kinetics of dermal absorption for the compound and formulation under study are required to arrive at the actual absorbed dose. For the oral and inhalation routes, exposure and absorbed dose are more closely equivalent than for the dermal route. However, for precise data, absorption must be taken into account for these routes, also. Second, indirect methods are based on measurement of some effect of the compound on the exposed individual (such as blood xiii In Dermal Exposure Related to Pesticide Use; Honeycutt, R., et al.; ACS Symposium Series; American Chemical Society: Washington, DC, 1985. cholinesterase level) or determination of the compound or its breakdown product(s) in the tissues or excreta (such as DDT in blood or p-nitrophenol in urine). In comparing these methods, the direct entrapment procedures give the advantage of providing an absolute value for a discrete exposure even within a sequence of repetitive exposures to the same pesticide. They can also be used to differentiate the relative contributions of oral, dermal, and respira tory exposure to the total exposure picture. This book provides an up-to-the-minute picture of the current status of research on measurement and risk assessment of dermal pesticide exposure for agricultural workers. The chapters also provide an insight into some newer areas (applications of mathematical models, use of fluorescent tracer materials, and extrapolation from a computer data base of generic pesticide exposure data) that will undoubtedl future. WILLIAM F. DURHAM Environmental Protection Agency Research Triangle Park, North Carolina December 1984 xiv In Dermal Exposure Related to Pesticide Use; Honeycutt, R., et al.; ACS Symposium Series; American Chemical Society: Washington, DC, 1985.