You are here:
RELATIONSHIPS OF METALS IN FLOOR DUST AND ON THE HANDS OF TODDLERS
Citation:
Freeman, N. G., E. D. Pellizzari, L J. Melnyk, AND M R. Berry Jr. RELATIONSHIPS OF METALS IN FLOOR DUST AND ON THE HANDS OF TODDLERS. Presented at ISEA Annual Conference, Monterey, CA, October 24-27, 2000.
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:
Toddlers are characterized by their frequent hand-to-mouth activity and exploratory behavior. This puts them at risk for exposure to environmental contaminants. Wipe samples are traditionally used to collect dust samples in homes. The assumption is that dust samples are indicative of what the child contacts and that loadings on children's hands should be similar to those found in the child's environment. As part of the Children's Dietary Lead Study hand wipes were obtrained from 45 toddlers; floor wipes were collected at the same time, with the same sampling medium. Analysis of wipe samples was conducted by ICP-MS for aluminum, arsenic, barium, cadmium, chromium, copper, lead, manganese, nickel, vanadium and zinc. No detectable chromium was found in any wipe sample. Aluminum and lead were found in all floor and hand wipe samples. Lead loadings (ng/cm2) on floor and hand wipes were correlated and were not significantly different in amount. In contrast, aluminum loadings on hands were not correlated with loadings from floor wipes and were significantly greater in amount. Median loadings were 413 and 71 ng/cm2 respectively. For many of the metals the propoRtion of samples with detectable levels was similar for hand wipes and floor wipes. However, arsenic and vanadium were found in more than 80% of hand wipe samples, yet less than 50% of floor wipe samples. For most of the metals, hand loadings were significantly greater than floor loadings. Two factors that may contribute to these differences are the multiple sources of exposure that the child experiences and differential particle size distributions that adhere to hands and are found on floors. The results suggest that for many metals hand loadings may exceed loadings found in environmental samples, and therefore are better indicators of exposure.