Organophosphate pesticides (OPs) continue to be widely used in the United States. There is little doubt that OPs are related to ill health among adults, especially farmworkers who are exposed to OPs as part of their regular work. Even more disturbing, however, is that farmworkers’ families, including children, are exposed to pesticides through the take-home pathway.
The overall goal of this portion of the pesticides project was to reduce the levels of pesticide exposure in children of farmworkers in the Yakima Valley of Washington state by breaking the pesticide “take-home” pathway. The specific aims to achieve this goal were:
The overall goal of this part was to investigate multiple pathways that may contribute to pesticide exposure in adults and children living in agricultural communities. The specific aims were:
This pathway has been demonstrated in our previous studies and children of farmworkers have been shown to have a threefold increase of dimethyl urinary pesticide metabolites compared to non-farmworker children in an agricultural area. In the past ten years of our Child Health Center (CHC) much has been learned about pesticide exposure and how pesticides are metabolized. It is known, for example, that individuals who have low levels of PON1 paraoxonase activity are slow metabolizers of some OP metabolites, making them more sensitive to the toxicity of certain OPs (for example, chlorpyrifos [CP] and chlorpyrifos oxon [CPO] versus azinphosmethyl (AZ) and its oxon (AZO), where such differences were less important). Our characterizations and those of our collaborators in the CHC have analyzed the episodic nature of OP usage in the agricultural practice in.
These observations, which are highly relevant for most agricultural regions in the US where four seasons exist, show the importance of characterizing both the within- and between-person variability in pesticide exposure and response. Past research on OP exposure has focused on limited sample collection; frequently, two or three “spot” samples (samples taken at one time during the day) gathered during limited times of the year, and thus have failed to adequately address factors related to individual and population level variability.
Common to all these studies has been the large within-person variability of the samples which reduces power to detect which factors are statistically significant between seasons; further, such evaluations have limited ability to identify highly exposed populations. In this project, we will address all three of these areas; specifically, we will: