Relative Pesticide and Exposure Route Contribution to Aggregate and Cumulative Dose in Young Farmworker Children

Abstract

The Child-Specific Aggregate Cumulative Human Exposure and Dose (CACHED) framework integrates micro-level activity time series with mechanistic exposure equations, environmental concentration distributions, and physiologically-based pharmacokinetic components to estimate exposure for multiple routes and chemicals. CACHED was utilized to quantify cumulative and aggregate exposure and dose estimates for a population of young farmworker children and to evaluate the model for chlorpyrifos and diazinon. Micro-activities of farmworker children collected concurrently with residential measurements of pesticides were used in the CACHED framework to simulate 115,000 exposure scenarios and quantify cumulative and aggregate exposure and dose estimates. Modeled metabolite urine concentrations were not statistically different than concentrations measured in the urine of children, indicating that CACHED can provide realistic biomarker estimates. Analysis of the relative contribution of exposure route and pesticide indicates that in general, chlorpyrifos non-dietary ingestion exposure accounts for the largest dose, confirming the importance of the micro-activity approach. The risk metrics computed from the 115,000 simulations, indicate that greater than 95% of these scenarios might pose a risk to children’s health from aggregate chlorpyrifos exposure. The variability observed in the route and pesticide contributions to urine biomarker levels demonstrate the importance of accounting for aggregate and cumulative exposure in establishing pesticide residue tolerances in food.

Modeling of Human Viruses on Hands and Risk of Infection in an Office Workplace Using Micro-Activity Data

“…We have previously demonstrated, using individual micro-level activity time series, that dermal exposure has greater between-individual variability that within-individual variability in part due to individual’s unique activity patterns. (8,9) It is like that certain people would be at increased risk for viral loading, as demonstrated by the high measured values, because of their own personal activity patterns and their proximity to contaminated fomites. In the future this model could be adapted into a simulation model whereby individual workers could be simulated and spatial and temporal components could be incorporated.…”

Chronic exposure to chlorpyrifos triggered body weight increase and memory impairment depending on human apoE polymorphisms in a targeted replacement mouse model

“…Nearly everybody present organophosphate residues in their bodies but display no symptomatology [11], so most exposures are below the acute poisoning threshold and are therefore undetected, like a silent pandemic [28]. In the general population, the dietary intake of pesticides is the most important source of exposure [4,49,65].…”

Maternal residential pesticide use and risk of childhood leukemia in Costa Rica

“…Notably, previous studies have used exposure assessment methods such as geographic information systems to map pesticide use near the homes,25 analysis of pesticide use registry data,26 measurement of pesticide residues in home dust samples,27 or assessment of parental report of living in an agricultural area with pesticide use 7. Associations between exposure to agricultural pesticides sprayed near the home and childhood leukemia could potentially be explained by the fact that, compared to children living in non‐agricultural areas, children living near farms may be disproportionately exposed to pesticides used in agriculture26, 29 through pathways including pesticide drift and the take‐home exposure pathway 30, 31, 32, 33…”