Sampling household surfaces for pesticide residues: comparison between a press sampler and solvent-moistened wipes

A modified Press Sampler was evaluated to determine the efficiency of pesticide transfer from household surfaces to collection disks as compared to wiping with a solvent-moistened gauze pad. Organophosphate (OP), pyrazole, and pyrethroid pesticides were applied to three hard flooring materials and carpet at two loading rates. Surfaces were dried and press sampled using C(18), 100% cotton or polyurethane foam (PUF) for either 2 or 10 min or wiped with isopropanol-moistened gauze pads. Transfer efficiencies (TE, %) were calculated as a fraction of surface loadings captured simultaneously on foil deposition coupons. The highest mean TEs (17-55%) for the Press Sampler were observed for OPs from hard surfaces to C(18), considering both contact times. Cotton and PUF transferred 6-27% and 5-30% of OPs, respectively. Corresponding mean TEs for pyrazole and pyrethroid pesticides were only 3% (C(18)), 2-3% (cotton) and 1-2% (PUF). Wipes of hard surfaces removed 84-97% of all pesticides while wipes of carpet removed 31-39%, much higher than transferred to any Press Sampler materials. The mean TEs suggested that the extent of pesticide residue transfer was affected by surface type, pesticide class, and sampling procedure. Wiping was more efficient than press sampling for pesticide surface residue measurements, particularly for loading rates typical of residences.