Biomarkers of pesticide exposure

Incorporation of biomarkers in studies of occupational exposure hazards is now recognized as a highly useful adjunct to the surrogate measures employed in the past, for example, time worked, ambient air data, interview responses. Application to studies of workers potentially exposed to pesticides has barely begun and provides many challenges to chemist/epidemiologist teams. This review indicates several excellent studies employing multiple-exposure measures to document the validity of specific biomarkers for particular exposure situations. In general, exposure reflected by urinary assays of specific pesticides is a low percentage of that indicated by dermal or breathing zone measures. Markers for many of the pesticides in current usage have yet to be developed and validated, and information on population variability is generally lacking for existing markers. The challenge provided by the complexity of multiple, and often unknown, exposures to individuals in pesticide environments has begun to be addressed employing cytogenetic or urinary measures that attempt to integrate these complex exposures. The lack of data regarding sensitivity and specificity of biomarkers, especially in complex exposure situations, is a major problem that perhaps will best be addressed by studies combining nonspecific measures with specific ones, utilizing stored sample banks created for that purpose. Expanding the repertoire of available biomarkers of pesticide exposure and employing multiple ones in well-designed study protocols will provide critical tools in the evaluation of pesticide safety and design of appropriate measures to minimize adverse exposures. Ironically, one of the problems that biological markers of exposure can help overcome, reliance on poorly measured ambient exposure data, hampers the evaluation of the markers themselves. Therefore, the combination of in vitro, animal, and human data will give the best picture of a marker's performance. (Wilcosky 1990).