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INTERIM RESULTS FROM THE AGRICULTURAL HEALTH STUDY/PESTICIDE EXPOSURE STUDY
Citation:
Thomas, K W., L S. Sheldon, S. M. Gordon, M. Jones, S. Reynolds, J. Raymer, G G. Akland, AND M. Dosemec. INTERIM RESULTS FROM THE AGRICULTURAL HEALTH STUDY/PESTICIDE EXPOSURE STUDY. Presented at International Soceity for Exposure Analysis, Vancouver, Canada, August 11-15, 2002.
Impact/Purpose:
The primary goal of the AHS Pesticide Exposure Study (AHS/PES) is to measure exposure to applied pesticides for a subset of the cohort of private pesticide applicators and to provide data to evaluate exposure algorithms developed for exposure classification in the study cohort.
Description:
The Agricultural Health Study (AHS) is a prospective epidemiological study of pesticide applicators and their spouses in Iowa and North Carolina. Exposure to 2,4-D or chlorpyrifos is being measured for a subset of applicators in the AHS Pesticide Exposure Study to assess exposure classification procedures. Applicators are selected based on their use of specific application methods and personal protective equipment. Potential exposures are measured on one day of pesticide mixing, loading, and application (MLA) using dermal patch, hand wipe, and personal air samples. Dermal samples are collected by placing ten cellulose or gauze patches on the body, with each patch sized proportionately to the body area it represents. Patches are combined for analysis. Hand wipe samples are collected using a sub-sampling technique that wipes approximately 10% of the hand surface area. Urinary biomarker levels are measured in pre-and post-application samples from each applicator and from participating spouses and children. Questionnaires and observations of MLA activities provide information about work practices, use of protective equipment, and hygiene. Field monitoring has been completed for 72 applicators, 35 spouses, and 10 children in 2000 and 2001 in Iowa and North Carolina and will continue in the spring/summer of 2002. Preliminary measurement results for urinary biomarkers show levels of 2,4-D in applicators' first post-application urine samples ranging from <1 to 480 g/g creatinine. Use of 2,4-D on days before and after the monitored MLA affected pre- and post-application urinary levels for some applicators, with 130 g/g creatinine measured prior to the monitored MLA for one applicator, and 1100 g/g creatinine measured several days after the monitored MLA for another. Spouse and child urinary biomarker levels of 2,4-D were <10 g/g creatinine, except for 68 g/g creatinine measured for one spouse. Urinary levels of the 3,5,6-trichloropyridinol metabolite of chlorpyrifos ranged from 2 to 16 g/g creatinine for chlorpyrifos applicators, their spouses, and children. Based on results for the eight 2,4-D and two chlorpyrifos applicators monitored in 2000, estimated dermal exposures ranged from 7 to 20,000 g per MLA activity (assuming 10% penetration of clothing) and estimated inhalation exposures ranged from 1 to 24 g per MLA activity. The two farmers applying a granular chlorpyrifos product experienced the lowest dermal and inhalation exposures. Measurement results and relationships between measurements, observed work practices, and the amount of applied active ingredient will be presented for all applicators monitored through the first two years.
This work has been funded in part by the U.S. Environmental Protection Agency. It has been subjected to Agency review and approved for publication. Mention of trade names of commercial products does not constitute endorsement or recommendation for use.