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RESEARCH IN EPA'S NATIONAL EXPOSURE RESEARCH LABORATORY (NERL) TO REDUCE UNCERTAINTIES IN CHILDREN'S EXPOSURE/RISK ASSESSMENTS
Citation:
Tulve, N S. RESEARCH IN EPA'S NATIONAL EXPOSURE RESEARCH LABORATORY (NERL) TO REDUCE UNCERTAINTIES IN CHILDREN'S EXPOSURE/RISK ASSESSMENTS. Presented at NCEA Seminar Series, Washington, DC, May 13, 2003.
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 US EPA has pledged to increase its efforts to provide a safe and healthy environment for children by ensuring that all EPA regulations, standards, policies, and risk assessments take into account special childhood vulnerabilities to environmental toxicants. To help explain the challenges and research needs associated with children's exposure to environmental pollutants, EPA/ORD developed a research strategy to improve risk assessments for children. Similarly, in support of the Food Quality Protection Act (FQPA) of 1996, EPA is required to upgrade the risk assessment procedures for setting pesticide residue tolerances in food by considering the potential susceptibility of infants and children to both aggregate and cumulative exposures to pesticides. Currently, the data on children's exposures and exposure factors are limited and generally not adequate to assess residential exposures to consumer products and environmental contaminants. Several areas of research need to be addressed to improve the quality and quantity of data available for exposure assessments for children.
The Children's Exposure Research Program at the EPA/NERL is designed to meet several research needs that have been identified in initial assessments of the adequacy of the data for estimating children's exposure to pesticides and environmental toxicants. The goal of the EPA/NERL measurement research program in support of FQPA is to develop and evaluate approaches and methods for assessing children's aggregate exposure to pesticides and to conduct studies to collect data required to reduce reliance on default assumptions in development of quantitative exposure assessments. Based on an initial assessment of critical exposure pathways and factors, researchers in the NERL identified four priority research areas where there are critical data gaps. These areas include: (1) pesticide use patterns, (2) spatial and temporal distribution of pesticides in residences and child care centers, (3) factors influencing dermal and indirect ingestion exposures, and, (4) dietary exposure. Targeted studies were designed and implemented to address these research needs. They included laboratory studies, small pilot field studies, analysis of available data sets, and two large studies in which EPA/NERL collaborated with other Federal agencies.
Research results from these studies were used to develop a Draft Protocol for Measuring Children's Non-Occupational Exposure to Pesticides by all Relevant Pathways and as input to the design of a large children's exposure measurements study. The Draft Protocol was developed to provide guidance for generating data that can be used to improve exposure assessments for young children. It fills a critical need for standardization of the approaches and methods for collecting exposure concentration and exposure factor data.
EPA/NERL has designed a two-year longitudinal study in which measurements will be made to estimate the aggregate exposures for children 3 months to 3 years of age to current-use indoor residential pesticides (primarily pyrethroids). The study will be conducted in the greater Jacksonville, FL area. Up to 100 young children will be enrolled into the study in two cohorts: (1) infants recruited into the study soon after birth, and, (2) young children recruited into the study at approximately 12 months of age. The overall goals of the field study are the following: (1) collect data that can be used for evaluation and refinement of the Draft Protocol, (2) improve our understanding of the important pathways of exposure for very young children, and, (3) evaluate the impact of developmental age and children's activities on indoor residential pesticide exposure. In addition, EPA/NERL has also written a proposal to the American Chemistry Council to add three additional classes of compounds: selected phthalates, brominated flame retardants, and perfluorinated compounds. This proposal is currently pending. The study design was externally peer-reviewed in August, 2002. The field measurement data collection will begin in Fall 2003, pending successful OMB submission.
This seminar will highlight ORD/NERL's research efforts to date to develop the Draft Protocol and the design for the longitudinal field measurement study to be conducted in Jacksonville, FL.
This is an abstract of a proposed presentation and does not necessarily reflect the United States Environmental Protection Agency (EPA) policy. The actual presentation has not been peer-reviewed by EPA. Mention of trade names or commercial products does not constitute endorsement or recommendation for use.