Geographic and record-based pesticide exposure assessment, biologic exposure signatures, and chronic disease modelling in California

Abstract

Background and Aims: For the past 50 years, California has been recording agricultural pesticide applications in a pesticide use reports (PUR) database; i.e. documenting use for several hundred pesticide active ingredients. These data can be employed in exposure assessment purposes targeting specific pesticides and pesticide mixtures and study a range of adverse health outcomes. Methods: In collaboration with M. Cockburn at USC, my team at UCLA has generated a geographic information system tool that uses these records in conjunction with land use data to generate spatio-temporal exposure measures for the California population living near agricultural applications. Over the past 2 decades we have used this tool kit to estimate pesticide related health effects including studies of adverse birth outcomes, autism, cerebral palsy, childhood brain cancers, Parkinson’s and Alzheimer’s disease. Results: I will present and discuss common as well as special challenges for exposure assessment and the results of the studies we conducted in the past 2 decades. Furthermore, we investigated whether long- or shorter-term exposures to agricultural use pesticides assessed with the PUR tools generate exposure signals in biological systems and bio-fluids, i.e. relying on human blood samples from older adult residents of central California to examine metabolomic patterns, methylation changes, and influences that certain pesticides have on the gut microbiome. Using integrative omics analyses, we also examined overlap between pesticide-associated biologic pathways and pathways known to be perturbed in certain diseases. Conclusions: These studies help to systematically identify physiologic responses to chronic pesticide exposures. Eventually this will help to better understand how low-level chronic pesticide exposures may contribute to chronic brain diseases in real world exposure scenarios. Keywords: pesticides, exposure assessment, Parkinson’s disease, neurodevelopment, multi-omics