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CHLORPYRIFOS ACCUMULATION PATTERNS FOR CHILD ACCESSIBLE SURFACES AND OBJECTIVES AND URINARY METABOLITE EXCRETION BY CHILDREN FOR TWO-WEEKS AFTER CRACK-AND-CREVICE APPLICATION
Citation:
HORE, P., M. ROBSON, N. C. FREEMAN, J. ZHANG, D. WARTENBERG, H. A. OZKAYNAK, N. S. TULVE, L. S. SHELDON, L. NEEDHAM, D. BARR, AND P. J. LIOY. CHLORPYRIFOS ACCUMULATION PATTERNS FOR CHILD ACCESSIBLE SURFACES AND OBJECTIVES AND URINARY METABOLITE EXCRETION BY CHILDREN FOR TWO-WEEKS AFTER CRACK-AND-CREVICE APPLICATION. ENVIRONMENTAL HEALTH PERSPECTIVES. Environmental Health Information Service, 113(2):211-219, (2005).
Impact/Purpose:
1. Identify and evaluate the factors that affect children's exposures as a function of age (for age bins proposed by EPA's Risk Assessment Forum).
2. Determine the impact of microenvironment and macroactivity on children's exposure to current-use pesticides and selected phthalates in residences.
3. Determine temporal variability of multimedia concentrations of selected pesticides and phthalates in the residences of very young children (0 to 3 years of age).
4. Perform aggregate exposure estimates for current-use pesticides (soon after application) and phthalates for very young children.
5. Evaluate the relationship between concentrations of biomarkers of exposure measured in urine and aggregate exposure estimates derived from diet and environmental measurements for pesticides and phthalates using the algorithms and approaches specified in the Draft Protocol for Measuring Children's Non-Occupational Exposure to Pesticides by all Relevant Pathways.
6. Evaluate and apportion exposure pathways for pesticides and phthalates.
7. Collect data for selected polybrominated diphenyl ethers (brominated flame retardants) and perfluorinated chemicals (PFOS and PFOA) in the diet and in environmental samples collected in the residences to assess spatial and temporal variability and the potential for children's exposure.
8. Evaluate the utility of the draft standardized protocol for performing exposure assessments for young children.
9. Develop critical inputs for the human exposure models (SHEDS, CARES, Lifeline, Calendex, and others).
10. Collect preliminary data on environmental concentrations of selected metals found in the outdoor residential environment.
11. Evaluate the utility of standardized data collection methods for future large scale studies.
Description:
The Children's-Post-Pesticide-Application-Exposure-Study (CPPAES) was conducted to look at the distribution of chlorpyrifos within a home environment for a 2-week period following a routine professional crack-and-crevice application, and to determine the amount of the chlorpyrifos that is absorbed by a child living within the home. Ten residential homes with a 2-5 year old child in each were selected for study, and the homes were treated with chlorpyrifos. Pesticide measurements were made of the indoor air, indoor surfaces and plush toys. In addition, periodic morning urine samples were collected from each of the children throughout the two-week period. The urine samples were analyzed for 3,5,6-trichloropyridinol, the primary urinary metabolite of chlorpyrifos, and the results were used to estimate the children's absorbed dose. Average chlorpyrifos levels in the indoor air and surfaces ranged from 26 (pre)/120 (post) ng/m3 and 0.48 (pre)/2.8 (post) ng/cm2, respectively, reaching peak levels between days 0-2; subsequently, concentrations decreased throughout the 2-week period. Chlorpyrifos in/on the plush toys ranged from 7.3-1949 ng/toy post-application, concentrations increasing throughout the 2-week period demonstrating a cumulative adsorption/absorption process indoors. The daily amount of chlorpyrifos estimated to be absorbed by the CPPAES children post-application ranged from 0.04-4.8 µg/kg/day. During the 2-week period following the crack and crevice application, there was no significant increase in the amount of chlorpyrifos absorbed by the CPPAES children.
The United States Environmental Protection Agency through its Office of Research and Development partially funded and collaborated in the research described here under Contract No. 0D-5227-NAEX to the Environmental and Occupational Health Sciences Institute. It has been subjected to Agency review and approved for publication.