Dermal Transfer of Chlorpyrifos Residues from Residential Surfaces: Comparison of Hand Press, Hand Drag, Wipe, and Polyurethane Foam Roller Measurements after Broadcast and Aerosol Pesticide Applications Chensheng Lu and Richard A. Fenske Department of Environmental Health, School of Public Health and Community Medicine, University of Washington, Seattle, Washington, USA Abstract Indoor residential pesticide applications present the potential for human exposures, particularly for small children. Personal contact with target and nontarget surfaces can result in transfer of pesticides to the skin, but the magnitude of such transfer is uncertain. This research compared surface sampling techniques [wipe and polyurethane foam (PUF) roller] with the removal ability of human skin following broadcast and total aerosol release applications of Dursban (Dow Elanco, Midland, MI) , a residential formulation containing the insecticide chlorpyrifos. Hands were washed immediately after surface contact, following a protocol that included a laboratory-generated adjustment factor to account for incomplete removal of chlorpyrifos from skin. Chlorpyrifos transfer was similar for hand press and hand drag techniques, averaging approximately 1-6 ng/cm2 of carpet contacted. These amounts represented < 1% of the amount of chlorpyrifos deposited on the surfaces 3.5 hr earlier. Chlorpyrifos transfer from carpet to skin was 23-24 times lower than for wipe sampling and 33-36 times lower than for PUF roller sampling (p = 0.0007 and p = 0.0006 for broadcast and aerosol applications, respectively) . Hand press sampling removed approximately 4.5 times less chlorpyrifos from nontarget furniture surfaces (12 ng/cm2) than did wipe sampling (56 ng/cm2 ; p = 0.009) . Chlorpyrifos residues on carpet were substantially higher after broadcast applications than after aerosol applications, but residues on such nontarget surfaces as furniture were substantially higher for the aerosol application. This study indicates that human skin removes substantially less residue from carpets and furniture than either conventional wipe or PUF roller sampling methods following residential pest control applications of chlorpyrifos. Although this paper focuses on quantifying residue transfer from surface to skin using different surface sampling techniques, no attempt is made to quantify the amount of chlorpyrifos residue that is subsequently absorbed. Key words: aerosol application, broadcast application, chlorpyrifos, dermal exposure, exposure assessment, flea control, handwash, insecticide, pesticides, residential application, skin, wipe sampling. Environ Health Perspect 107:463-467 (1999) . [Online 27 April 1999] http://ehpnet1.niehs.nih.gov/docs/1999/107p463-467lu/ abstract.html Address correspondence to C. Lu, Department of Environmental Health, Box 357234, University of Washington, Seattle, WA 98195-7234 USA. Telephone: (206) 685-9299. Fax: (206) 616-2687. E-mail: calu@u.washington.edu This research was supported primarily by the U.S. Environmental Protection Agency Office of Research and Development (cooperative agreement CR816044) and the New Jersey Department of Environmental Protection Division of Science and Research (contract P31128) . This work was conducted at both the New Jersey Agricultural Experiment Station and the University of Washington Department of Environmental Health and was supported in part by these institutions. Special thanks to J. Louis and M. Robson for project guidance and to those individuals who volunteered for this study. Received 28 July 1998 ; accepted 26 January 1999. The full version of this article is available for free in HTML format. |