Behavioral observation used to estimate pesticide exposure for farm workers in Brazil

Abstract

Assessment of the harm caused by exposure to pesticides requires that a measure of exposure be available. While such information is available without difficulty in controlled laboratory studies, estimating the exposure of humans who have been exposed in the real world is difficult. The difficulty is increased if exposures have taken place over an extended time period and the documentation of specifics is unavailable. Three methods of exposure assessment have previously been used: comparison of exposed and non-exposed groups, estimation of exposures through self-report of the individuals, and estimation of exposure through assessment of biomarkers or environmental levels. Each approach imposes limitations. We propose an additional approach - estimation of the degree of exposure for individuals through direct observation of their behavior and their use of personal protective equipment (PPE) during periods of exposure. We also obtain opinions from experts regarding the risk associated with the various behaviors and PPE use and combine these with the observations to create a personal risk index for each individual. By including information on chemicals in use during this period, we can characterize recent (observed) exposure for that individual. By these steps, the degree of risk may be determined for recent (observed) exposure. An estimate of long-term risk resulting from work-related exposures can be obtained for individuals by summing across their work histories.