Survey of Pesticide Residues in Loose Particles on Hardscape Surfaces

Loose particles on impervious surfaces are an important carrier to transfer pesticides into residential runoff water and subsequently contribute to contamination of urban streams and estuaries by urban-use pesticides. However, data regarding levels of pesticide contamination in the runoff-transferable dusts are scarce and their runoff potential and toxicity impacts to urban watersheds still remains poorly understood. In this study, a surface vacuuming method was used to collect dusts from residential outdoor impervious surfaces and samples were analyzed for concentrations of 14 legacy and current-use pesticides including pyrethroids, fipronil, fipronil metabolites, chlorpyrifos and diazinon. A total of 360 dust samples from curbside gutter, sidewalk and street surfaces were collected from 40 residential homes belonging to two residential communities in southern California. Each house was sampled three times in the year of 2011, i.e., May, July and September.