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DATA COLLECTED IN THE EPA'S NATIONAL EXPOSURE RESEARCH LABORATORY'S FIELD MEASUREMENT STUDIES TO EVALUATE AGGREGATE EXPOSURE
Citation:
Tulve, N S., R C. Fortmann, E A. CohenHubal, AND L S. Sheldon. DATA COLLECTED IN THE EPA'S NATIONAL EXPOSURE RESEARCH LABORATORY'S FIELD MEASUREMENT STUDIES TO EVALUATE AGGREGATE EXPOSURE. Presented at Society of Risk Analysis Annual Meeting, Baltimore, MD, December 7-10, 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 Food Quality Protection Act of 1996 requires children's risk assessments to be conducted using high quality and high quantity data. Currently, data on children's exposures and exposure factors are limited and insufficient to address risk assessments that do not rely heavily on default assumptions. Researchers in the U.S. Environmental Protection Agency's National Exposure Research Laboratory (NERL) have been conducting human exposure measurement studies to collect environmental, biological, and activity pattern data that can be used in the risk assessment process to evaluate young children's potential exposures to pesticides in order to reduce the reliance on standard default assumptions. Inhalation, dermal, and ingestion algorithms for indoor and outdoor locations where young children may spend their time are evaluated using the field measurement and exposure factor data collected. In addition, pesticide inventories, time-activity diaries, household habits, and occupant characteristics are collected to aid in the exposure assessment. Our systematic approach to collecting measurement and exposure factor data has helped us to recognize where the biggest data gaps and uncertainties still exist. For example, indirect ingestion exposure factors are difficult to quantify in field studies. This presentation will focus on the various types of data collected in the NERL's field measurement studies to help better characterize the exposure factors needed by the U.S. EPA's Office of Pesticide Programs to understand and evaluate young children's potential exposures. We will also discuss ways to reduce the data gaps that still exist.
This work has been funded wholly or in part by the United States Environmental Protection Agency. It has been subjected to Agency review and approved for publication.