Background
Chlorpyrifos is an organophosphate, a class of pesticide associated with numerous adverse health outcomes. Organophosphates are considered acetylcholinesterase (an enzyme) inhibitors . Chlorpyrifos kills pests by blocking acetylcholinesterase, which controls messages between nerve cells. The nervous system malfunctions and eventually kills the pest.
After exposure, chlorpyrifos is broken down to a toxic form called chlorpyrifos oxon and this form is what permanently binds to acetylcholinesterase. Acetylcholine usually binds to cholinergic receptors and unbinds with the help of acetylcholinesterase. If the acetylcholine cannot unbind from its receptor, then muscles will stay in a contracted state and cause paralysis.
People can be exposed to chlorpyrifos by inhaling air from a crop-dusted field, by ingesting foods that have been treated with the pesticide or by drinking contaminated water from wells. Additionally, it can cause harm if the eyes and skin are exposed.
Children are most susceptible to social behavior and brain development disorders from chlorpyrifos exposure. They are more likely to be exposed since children like to put their hands inside their mouths than adults. Children may also have trouble metabolizing pesticides and the dose amount is larger due to their decreased size.
PUBLICATIONS
Organophosphate (OP) pesticides are widely used in California for agricultural pest and weed control despite their well-documented adverse health effects among infants, children, and adults. We sought to identify factors affecting urinary OP metabolites among families living in high-exposure communities. Our study included 80 children and adultswho lived within 61 m (200 ft) of agricultural fields in the Central Valley of California in January and June 2019,which are pesticide non-spraying and spraying seasons, respectively. We collected one urine sample per participantduring each visit to measure dialkyl phosphate (DAP) metabolites; these were coupled with in-person surveys to identify health, household, sociodemographic, pesticide exposure, and occupational risk factors. We used a data-driven, best subsets regression approach to identify key factors that influenced urinary DAPs. Participants were mostly His-panic/Latino(a) (97.5 %), over half were female (57.5 %), and most households reported having a member who worked in agriculture (70.6 %). Among the 149 urine samples suitable for analysis, DAP metabolites were detected in 48.0 % and 40.5 % of samples during January and June, respectively. Total diethyl alkylphosphates (EDE) wereonly detected in 4.7 % (n = 7) of samples, but total dimethyl alkylphosphates (EDM) were detected in 41.6 %(n = 62) of samples. No differences were observed in urinary DAP levels by visit month or by occupational exposureto pesticides. Best subsets regression identified several individual- and household-level variables that influenced both urinary EDM and total DAPs: the number of years spent living at the current address, household use of chemical products to control mice/rodents, and seasonal employment status. Among adults only, we identified educational attainment (for total DAPs) and age category (for EDM) as significant factors. Our study found consistent urinary DAP metabolites among participants, regardless of spraying season, and identified potential mitigating factors that members of vulnerable populations can implement to protect their health against OP exposure.
Organophosphate (OP) pesticides are associated with numerous adverse health outcomes. Pesticide use data are available for California from the Pesticide Use Report (PUR), but household-and individual-level exposure factors have not been fully characterized to support its refinementas an exposure assessment tool. Unique exposure pathways, such as proximity to agriculturaloperations and direct occupational contact, further complicate pesticide exposure assessment amongagricultural communities. We sought to identify influencing factors of pesticide exposure to supportfuture exposure assessment and epidemiological studies. Household dust samples were collectedfrom 28 homes in four California agricultural communities during January and June 2019 andwere analyzed for the presence of OPs. Factors influencing household OPs were identified by adata-driven model via best subsets regression. Key factors that impacted dust OP levels includedhousehold cooling strategies, secondary occupational exposure to pesticides, and geographic locationby community. Although PUR data demonstrate seasonal trends in pesticide application, this studydid not identify season as an important factor, suggesting OP persistence in the home. These resultswill help refine pesticide exposure assessment for future studies and highlight important gaps in the literature, such as our understanding of pesticide degradation in an indoor environment.
FACTORS ASSOCIATED WITH LEVELS OF ORGANOPHOSPHATE PESTICIDES IN HOUSEHOLD DUST IN AGRICULTURAL COMMUNITIES (2022)
Organophosphate (OP) pesticides are associated with numerous adverse health outcomes. Pesticide use data are available for California from the Pesticide Use Report (PUR), but household- and individual-level exposure factors have not been fully characterized to support its refinement as an exposure assessment tool. Unique exposure pathways, such as proximity to agricultural operations and direct occupational contact, further complicate pesticide exposure assessment among agricultural communities. We sought to identify influencing factors of pesticide exposure to support future exposure assessment and epidemiological studies. Household dust samples were collected from 28 homes in four California agricultural communities during January and June 2019 and were analyzed for the presence of OPs. Factors influencing household OPs were identified by a data-driven model via best subsets regression. Key factors that impacted dust OP levels included household cooling strategies, secondary occupational exposure to pesticides, and geographic location by community. Although PUR data demonstrate seasonal trends in pesticide application, this study did not identify season as an important factor, suggesting OP persistence in the home. These results will help refine pesticide exposure assessment for future studies and highlight important gaps in the literature, such as our understanding of pesticide degradation in an indoor environment.