Organophosphate pesticides have been associated with several negative health outcomes, including cancer, neurodegenerative disease, impaired neurocognitive development, and adverse respiratory health effects. Specifically, the insecticide chlorpyrifos, which was banned from indoor use in the United States in 2000, has been under federal consideration to be discontinued from use in agriculture. In 2020, the State of California took the unprecedented action of banning chlorpyrifos in all agricultural applications by the end of the calendar year. This policy results in a unique natural experiment to determine changes in exposure and associated health effects to chlorpyrifos in the state. As the Central Valley of California is one of the most fertile agricultural regions in the world, this shift in pesticide use may have short-term and long-term effects on Valley residents who have household exposure based on community proximity to agricultural operations. Though California has an extensive publicly available agricultural pesticide application database (California Pesticide Use Registry), current data availability is generally delayed by two years. As such, evaluation of exposure changes in Valley communities and residents may not be documented for several years. Following, collection of biomarkers of exposure among Valley residents will provide the most rapid evidence of changes in exposure and concomitant health outcomes. Based on our previous work in the Central Valley, we have recruited a cohort of residents who live in four communities with high exposure to organophosphate pesticides including chlorpyrifos. In partnership with a long-standing environmental justice community organization in the region, we will leverage this existing cohort of 70 adult residents to determine exposure and associated short-term health effects prior to implementation of the ban and post-ban. We will recruit an additional 90 adult residents across the original four high exposure communities, two additional high exposure communities and one control community to determine change in exposure associated with the ban. We will evaluate pesticides in household dust and in urine, to determine changes in chlorpyrifos levels and potential changes in other pesticides that may serve as chemical replacements for chlorpyrifos (Aim 1). In addition, we will measure biomarkers of inflammation to determine if there are short term health effects that can be evaluated in the year after the California ban (Aim 2). Our proposed inflammatory markers underlie many disease states associated with pesticide exposure and allows us to develop a cohort to ascertain long-term health effects of the chlorpyrifos ban. This time-sensitive mechanism allows us a novel opportunity to add to the epidemiological literature on the health effects of chlorpyrifos, and evaluation of state-level policies to serve as a mechanism for potential improvements in environmental health.
Significance to Public Health. Agricultural pesticides are environmental exposures with demonstrated negative effects on human health. The State of California has decided to ban the organophosphate pesticide chlorpyrifos from agricultural use at the end of 2020. This policy change allows for a unique natural experiment to understand changes in chlorpyrifos exposure and short-term health effects potentially associated with the exposure among community residents who have high exposure levels. Results from this study can provide novel evidence of the effect of pesticides on health and serve as a foundation for more long-term studies of the health effects of pesticides.
