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MEASUREMENTS OF TRANSFERRABLE RESIDUE FROM CERAMIC TILE, VINYL TILE, HARDWOOD FLOORING, AND CARPET USING A PRESS SAMPLER AND C18, PUF, AND COTTON SAMPLING DISKS
Citation:
Bernard, C E., L J. Melnyk, AND M R. Berry Jr. MEASUREMENTS OF TRANSFERRABLE RESIDUE FROM CERAMIC TILE, VINYL TILE, HARDWOOD FLOORING, AND CARPET USING A PRESS SAMPLER AND C18, PUF, AND COTTON SAMPLING DISKS. Presented at ISEA Annual Meeting, Vancouver, Canada, August 11, 2002.
Impact/Purpose:
The purpose of this research is to reduce uncertainties in exposure assessments of young children by improving EPA's ability to measure exposures in the context of aggregate and cumulative exposure assessments. The general objective of this research is to support FQPA children's exposure assessment efforts by improving procedures and reducing uncertainty in measurements for dietary exposure of young children, a critically needed area for improved risk assessment. Specifically, this research will evaluate a protocol and companion model for measuring or otherwise assessing the combined dietary intake of a young child as influenced by pesticides, or other environmental contaminants, which contaminate their foods during the eating process (indirect ingestion exposure). This research will continue to develop the important factors which are needed to characterize excess intake of pesticides by young children. Specifically, the research will measure pesticide surface transfer efficiencies for food contacts with surfaces and eating activity patterns of young children that define the frequency of contacts with contaminated surfaces. A series of reports/products are anticipated by the end of FY05.
Description:
Unintentional and avoidable human exposure is a consequence of pesticide use indoors. Pesticides on household surfaces are a source of exposure to children. Therefore, concern has been raised regarding the potential for contamination of foods in homes where pesticides have been used. The exposure pathways that contribute to total dietary intake of pesticides for infants and children are believed to be different than that of adults. This includes indirect dietary exposure through either direct contact between foods and contaminated surfaces (surface-to-food transfer) and/or through an intermediate, such as hands (surface-to-hands-to-food transfer). Accurate measurements of surface residue transfer are needed to determine the extent of pesticide transfer to foods handled and/or eaten by a child. Consequently, a method is needed to measure pesticide residues available on surfaces. Wiping surfaces with a solvent moistened cotton gauze has been an accepted method for measuring surface residues, but the use of solvents can mar the sampled surface, which would be an unacceptable outcome for field sampling. Alternatively, a surface press sampler that presses C18 sampling disks (3M TM Empore TM Extraction disks composed of 90% Octadecyl adsorbent particle and 10% inert PTFE) against a surface for a specified period of time with a constant applied force has been used to measure transferable surface residue. The C18 disks, which adsorb and/or absorb the residue during contact with the surface, are removed, extracted in solvent and analyzed for the transferred surface residue concentration. The objective of this study was to determine if a surface press sampler in conjunction with either dry preconditioned C18 polyurethane foam (PUF; 1/4" thickness) or cotton (100% natural cotton) disks could be used to obtain transferable residue information from household surfaces. The extent of surface residue transfer to the C18, PUF and cotton dosimeter disks were then compared to isopropanol surface wipes. The surfaces tested consisted of ceramic tile, vinyl tile, hardwood flooring, and carpet. Each surface was contaminated with an aqueous solution of pesticides commonly used and/or found in homes (diazinon, malathion, chlorpyrifos, fipronil, cypermethrin, deltamethrin, cyfluthrin and permethrin) at loading rates of 0.1 and 1 ug/cm2, which are similar to previously measured deposition levels reported from residential monitoring of broadcast and total release aerosol applications. Following spraying, each surface was allowed to dry then duplicate contaminated surfaces were press sampled for surface contact times of 2,5,10, and 60 min. The extent of residue transfer to C18, PUF and cotton disks were compared and will be reported as percentages of pesticides transferred based on wipes. Future studies will include comparing the extent of residue transfer to the disks with that of pesticide transfer to food items.