Factors influencing household organophosphate pesticide levels in agricultural communities

Abstract

Background Organophosphate (OP) pesticide exposure is associated with various cancers, neurodegenerative diseases, and respiratory health outcomes. Proximity to agricultural operations and direct occupational contact are hypothesized to be important routes of exposure. Understanding these routes and exploring methods to estimate exposure will improve epidemiological studies, especially among agricultural communities where pesticide exposure due to drift and indirect contact is disproportionally high. To understand factors that influence household environmental exposures to OPs, we collected dust samples from homes in the Central Valley of California. We hypothesized that OP levels would be higher among samples collected during the agricultural spraying season and from homes in which a household member worked in agriculture. Methods Household dust samples were collected using a high-volume small surface sampler during the agricultural spraying (June) and non-spraying (January) seasons from 28 households located within 200 feet of agricultural fields. T-tests and paired t-tests were conducted to assess differences in total OP levels by occupational status and spraying season. Results A total of 50 samples were analyzed for the presence of OPs. Homes in which a household member worked in agriculture had significantly higher OP levels (130.0 parts per billion (ppb), SD 168.5), compared to homes without anyone working in agriculture (28.7 ppb, SD 24.2; p-value=0.001). No statistically significant differences were detected by spraying season (t=0.41, p-value = 0.69). Conclusions Our results demonstrate that detectable levels of OPs are prevalent in households within 200 feet of agricultural fields. Additionally, OPs may persist indoors for extended periods of time. Although the California Pesticide Use Registry indicates that OP application in our study area is seasonal, dust samples had similar levels across seasons. Our work will inform future research by revealing important factors related to routes of exposure to harmful pesticides experienced by agricultural workers and their families.