United States Environmental Protection Agency Office of Research and Development National Exposure Research Laboratory Research Abstract Government Performance Results Act (GPRA) Goal 3 Annual Performance Measure 253 Significant Research Findings: Understanding Exposure Factors that may Lead to High-Level, Short-Term Exposures of Children to Pesticides Scientific The U.S. Environmental Protection Agency has pledged to increase its efforts to Problem and provide a safe and healthy environment for children. The Food Quality Protection Policy Issues Act of 1996 (FQPA), for example, requires that children's risks to pesticide exposures be considered during the tolerance-setting process. FQPA requires exposure assessments to be conducted for all pesticide sources. It also requires that assessments use high quality and high quantity exposure data or models based on exposure factors generated from existing, reliable data. Currently, data on children's exposures and activities are insufficient to support quantitative exposure assessments. Rather, they rely heavily on major default assumptions as substitutes for missing information. An initial assessment of critical exposure pathways and factors for assessing children's residential exposures to pesticides indicated that data gaps existed in four areas: pesticide use patterns, spatial and temporal distributions of pesticides in residential dwellings, dermal exposure assessment, and dietary ingestion to include indirect ingestion due to the food handling by children. Studies are needed to obtain a better understanding of the factors impacting children's exposure to pesticides and to generate data for homes and daycare centers. The objective of this program was to identify the pesticides, pesticide use patterns, exposure pathways, and activities that represent the highest potential exposures to children and the factors that influence these exposures. To address these objectives, a set of targeted laboratory and pilot field studies were conducted to collect data to address one or more of the four focus areas of research. Pesticide concentrations were measured indoors and outdoors at homes and daycare centers for children 8 months to 5 years of age; laboratory and small field studies were conducted to develop dermal transfer efficiency data and transfer coefficients; children's activity pattern data were collected; and protocols for measuring and assessing aggregate exposures were developed and tested in the field. Children's exposures to pesticides and the factors impacting exposure have been evaluated in laboratory and field measurement studies. Results of these measurements have specifically addressed the following: Development and evaluation of a quantitative video fluorescent tracer for Research Approach Results and Impact ------- measuring transfer of pesticide residues from surfaces to hands with repeated contacts. Characterization of pesticide residue transfer efficiencies using a fluorescent tracer. Evaluation of pesticide occurrence and distributions in daycare centers. Measurements of pesticide occurrence and surface residue concentrations in homes. Estimates of aggregate exposures of children to pesticides in residences. Evaluation of the macroactivity approach for assessing children's dermal exposure. Measurements of transfer coefficients for estimating dermal and indirect ingestion exposure. Evaluation of human exposure to pet-borne diazinon residues following lawn application. Results of these studies will be used by EPA's Office of Pesticide Programs and National Center for Environmental Assessment, as well as the pesticide industry, to better understand the important factors for children's exposures . Data from these studies can be used to replace and/or refine default assumptions, thereby reducing the uncertainty in the risk assessments for pesticides and other persistent pollutants. The children's exposure measurements research in support of FQPA are being conducted by EPA's National Exposure Research Laboratory, with support from the Research Triangle Institute and the Battelle Memorial Institute under contract to the EPA. Additionally, work is being performed in collaboration with the Centers for Disease Control and Prevention, the Department of Housing and Urban Development, the Consumer Product Safety Commission, and the Duval County Health Department located in Jacksonville, FL. Examples of publications from this research program include the following: E.A. Cohen Hubal, L.S. Sheldon, J.M. Burke, T.R. McCurdy, M.R. Berry, M.L. Rigas, V.G. Zartarian and N.C.G. Freeman. (2000) Children's exposure assessment: A review of factors influencing children's exposure, and the data available to characterize and assess that exposure. Environmental Health Perspectives. 108(6): 475-486. E.A. Cohen Hubal, L.S. Sheldon, M.J. Zufall, J.M. Burke, K.W. Thomas. (2000) The challenge of assessing children's residential exposure to pesticides. Journal of Exposure Analysis and Environmental Epidemiology, 10(6), Part 2: 638-649. Morgan, M., D.M. Stout II, and N. Wilson. (2001) A feasibility study of the potential for human exposure to pet-borne diazinon residues following lawn applications. Bulletin of Environmental Contamination and Toxicology 66(3):295-300. Tulve, N.S., J.C. Suggs, T. McCurdy, E.A. Cohen Hubal, and J. Moya. (July, 2002) Frequency of mouthing behavior in young children. Journal of Exposure Analysis and Environmental Epidemiology 12(4):259-264. Stout, D.M. II and M.A. Mason. (2003) The distribution of chlorpyrifos following a crack and crevice type application in the U.S. EPA indoor air quality research house. Indoor Air (in press). Rohrer, C.A., T.E. Hieber, L.J. Melnyk, and M.R. Berry (2003). Transfer efficiencies of pesticides from household flooring surfaces to foods. Journal of Exposure Analysis and Environmental Epidemiology (in press). Research Collaboration and Research Products ------- Melnyk, L.J., C.E. Bernard, J.N. Morgan, and M.R. Berry (2003) Excess exposures of young children eating in contaminated environments. Environmental Health Perspectives (submitted). E.A. Cohen Hubal, J.C. Suggs, M.G. Nishioka, W.A. Ivancic (2003). Characterizing pesticide residue transfer efficiencies using a fluorescent tracer imaging technique. Journal of Exposure Analysis and Environmental Epidemiology (submitted). Ivancic W.A., M.G. Nishioka, R.H. Barnes, and E.A. Cohen Hubal. (2003). Development and evaluation of a quantitative video fluorescence imaging system and fluorescent tracer for measuring transfer of pesticide residues from surfaces to hands with repeated contacts. Annals of Occupational Hygiene (submitted). Future Research Results of these studies have been used to design a large aggregate exposure study of infant's and toddler's exposure to pesticides and persistent organic chemicals in their homes, as described in the research abstract for the "Design for a Field Study to Evaluate Protocols for Obtaining Reliable Data on Children's Exposure to Pesticides," (FY03 APM 244). The study has been designed to develop reliable protocols for estimating exposure for all relevant pathways and children's age groups, develop critical inputs for models used in the regulatory process, develop exposure factors as a function of age/developmental stage, evaluate age and development-related differences in young children's exposures, determine the impact of children's activities at different development ages on exposure, and develop a core data set of high quality exposure concentration measurements. The proposed longitudinal field study will be implemented over the next three years. ------- Contacts for Questions and inquiries can be directed to the principal investigators: Additional Nicolle Tulve, Ph.D. Information jj.S. EPA, Office of Research and Development National Exposure Research Laboratory MD E205-04 Research Triangle Park, NC, 27711 Phone: 919-541-1077 E-mail: tulve.nicolle@,epa.gov Roy Fortmann, Ph.D. U.S. EPA, Office of Research and Development National Exposure Research Laboratory MD E205-04 Research Triangle Park, NC, 27711 Phone: 919-541-1021 E-mail: fortmann.rov@,epa.gov Linda Sheldon, Ph.D. U.S. EPA, Office of Research and Development National Exposure Research Laboratory MD E205-01 Research Triangle Park, NC, 27711 Phone: 919-541-2205 E-mail: sheldon.linda@,epa.gov Lisa Melnyk, Ph.D. U.S. EPA, Office of Research and Development National Exposure Research Laboratory Mail Code 564 Cincinnati, OH, 45268 Phone:513-569-7494 E-mail: melnvk.lisa@,epa.gov Extramural federal funding for this research was administered under EPA contracts 68-D-99011 (Battelle Memorial Institute) and 68-D-99-012 (Research Triangle Institute). ------- |