Determinants of agricultural pesticide concentrations in carpet dust

Abstract

Background: Residential proximity to agricultural pesticide applications has been used as a surrogate for exposure in epidemiologic studies, although little is known about the relationship with levels of pesticides in homes.

Objective: We identified determinants of concentrations of agricultural pesticides in dust.

Methods: We collected samples of carpet dust and mapped crops within 1,250 m of 89 residences in California. We measured concentrations of seven pesticides used extensively in agriculture (carbaryl, chlorpyrifos, chlorthal-dimethyl, diazinon, iprodione, phosmet, and simazine). We estimated use of agricultural pesticides near residences from a statewide database alone and by linking the database with crop maps. We calculated the density of pesticide use within 500 and 1,250 m of residences for 180, 365, and 730 days before collection of dust and evaluated relationships between agricultural pesticide use estimates and pesticide concentrations in carpet dust.

Results: For five of the seven pesticides evaluated, residences with use of agricultural pesticides within 1,250 m during the previous 365 days had significantly higher concentrations of pesticides than did residences with no nearby use. The highest correlation with concentrations of pesticides was generally for use reported within 1,250 m of the residence and 730 days before sample collection. Regression models that also accounted for occupational and home use of pesticides explained only a modest amount of the variability in pesticide concentrations (4-28%).

Conclusions: Agricultural pesticide use near residences was a significant determinant of concentrations of pesticides in carpet dust for five of seven pesticides evaluated.

Conflict of interest statement

R.B.G., P.R., R.R., and A.H. are employed by the Cancer Prevention Institute of California (Berkeley, CA, USA). M.A. is employed by Westat, Inc. (Rockville, MD, USA), which conducted geographic analysis. M.N. is employed by Battelle Memorial Institute (Columbus, OH, USA), which conducted laboratory analysis. The authors declare they have no actual or potential competing financial interests.

Figures

Figure 1

Metric used to estimate density of pesticide use (kg/km2) within a circular buffer around a home using CPUR data only, where 10 kg (5 kg + 5 kg) simazine was applied to the section in the lower right quadrant with 20% of its land area within 500 m of the residence. The resulting simazine use density was (10 kg × 0.2)/0.785 km2 = 2.5 kg/km2 by the CPUR method.

Figure 2

Metric used to estimate density of pesticide use (kg/km2) within a circular buffer around a home using CPUR data linked to crop maps (CROP), where 5 kg simazine was applied to a field in the section in the lower right quadrant with 25% of its area within 500 m and 5 kg simazine was applied to another field with 0% of its area within 500 m. The resulting simazine use density was (5 kg × 0.25 + 5 kg × 0)/0.785 km2 = 1.6 kg/km2 by the CROP method.