Abstract

Accurate assessment of (occupational) exposure to pesticides is hard to achieve. Applicators often apply multiple products and active ingredients over the course of a growing season. Which active ingredient is applied will also depend heavily about the pest at hand. Exposure to pesticides is therefore often to a mixture of active ingredients when assessed at annual or lifetime scale. Recollection of this information can become rather problematic when it covers multiple decades especially in the absence of spraying calendars or other recorded data. Also, applicators might have reasonable knowledge of tradenames and active ingredients, but farmworkers exposed via re-entry tasks like harvesting, pruning etc. in treated crops might only remember a pungent smell of a particular active ingredient or the crop they worked in. In middle- and low-income countries this might even become more problematic given that considerable proportions of applied pesticides may originate from unauthorised sources and sometimes reach local retailers via illegal cross-country trade. Re-packaging, lack of information in local languages and illiteracy will enhance these problems. In epidemiological studies several exposure assessment approaches have been applied including self-reports by farmers and applicators, crop-exposure matrices, semi-quantitative algorithms based on detailed information provided by study subjects and less frequently by measuring exposure and biomonitoring. In this presentation an overview of and trends in methods for assessment of exposure to pesticides in agricultural cohort and cross-sectional studies as well as community-based (case-control) studies will be presented. The (lack of) validity of different methods and approaches will be considered.