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DDJC Tracy <br /> INITIAL RELEASE <br /> Estimated Exposure Dose for Incidental Ingestion of Day Care Center Play Yard Surface <br /> Soil <br /> j Metals (i.e., arsenic, chromium, and vanadium) and pesticides (i.e., 1,1-dichloro-2,2-bis(p- <br /> chlorophenyl)ethylene [DDE], 1,1,1-trichloro-2,2-bis(p-chlorophenyl)ethane [DDT], and dieldrin) <br /> were present in the Day Care Center play yard surface soil at levels above ATSDR comparison <br /> values, but often typical of background concentrations. To determine the health significance of <br /> exposure to these contaminants in the surface soil, ATSDR estimated an oral exposure dose from <br /> incidental ingestion of soil for a child using very conservative assumptions. ATSDR(pica) <br /> evaluates soil <br /> exposure for a child via ingestion because pronounced hand-to-mouth activity behavior <br /> 1 displayed by young children provides their greatest contribution to their overall exposure. <br /> ATSDR used the following equation to estimate exposure doses for incidental ingestion of Day <br /> Care Center play yard surface soil: <br /> Estimated exposure dose= Conc x IR x EF x ED x CF <br /> BW x AT <br /> where: <br /> Conc. = Maximum concentration in the surface soil (ppm) <br /> IR = Ingestion rate: child = 200 mg/day <br /> EF = Exposure frequency, or number of exposure events per year of exposure: <br /> 5 days/week x 50 weeks/year or 250 days per year attendance at the day care <br /> ED = Exposure duration, or the duration over which exposure occurs= 6 years <br /> CF = Conversion factor, 10-6kg/mg <br /> BW = Body weight (kg): child (1 to 6 years of age) = 16 kg <br /> AT = Averaging time or the time period over which cumulative exposures are averaged (6 <br /> years x 365 days/year) <br /> Likelihood of Health Effects From Ingestion of Day Care Center Play Yard Surface Soil <br /> Table C-3 summarizes the estimated exposure doses via ingestion of the Day Care Center's play <br /> yard surface soil. As the table indicates, estimated doses are less than corresponding health <br /> guidelines (i.e., MRLs or RtDs). On the basis of these findings, ATSDR concludes that incidental <br /> ingestion of soil is not likely to be harmful for young children playing in the Day Care Centers's <br /> yard. ATSDR also concludes that dermal contact with play yard soil is unlikely to lead to adverse <br /> health effects. If we conservatively assume that contaminant concentrations entering the body <br /> C-5 <br />