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TIME-INTEGRATED EXPOSURE MEASURES TO IMPROVE THE PREDICTIVE POWER OF EXPOSURE CLASSIFICATION FOR EPIDEMIOLOGIC STUDIES
Citation:
Robertson, G L., S C. Hern, AND K R. Rogers. TIME-INTEGRATED EXPOSURE MEASURES TO IMPROVE THE PREDICTIVE POWER OF EXPOSURE CLASSIFICATION FOR EPIDEMIOLOGIC STUDIES. Presented at National Children's Study Meeting, Baltimore, MD, December 17-18, 2002.
Impact/Purpose:
The overall objective of the NERL NCS Pilot Project is to investigate optimal approaches for the exposure measurements needed to support the planned Interagency National Children's Study. The objective of this task is to increase the scientific effectiveness of epidemiologic designs while minimizing costs by addressing exposure misclassification.
Description:
Accurate exposure classification tools are required to link exposure with health effects in epidemiological studies. Although long-term integrated exposure measurements are a critical component of exposure assessment, the ability to include these measurements into epidemiological studies is often limited by time, budget, and compliance issues. Another problem which arises when determining the sources, routes, and pathways of exposure to pesticides and other chemicals is the lag time between collection of a sample and the receipt of the results. Current methods which use laboratory analysis may take 30-60 days, or longer, to obtain results. This means that the source of exposure may be gone by the time it is discovered that the child has been exposed, given the relatively short half-lives of many compounds. Screening techniques could direct attention to the most highly exposed (to particular indicator compounds) population of children for which multiroute, multimedia monitoring would be of value. In addition, stratification of the study population (i.e., the majority of the environmental/biological samples collected from the "highly exposed population"of children) often is required, given the expense of multiroute, multimedia monitoring (numerous non-detect results are counterproductive in determining sources). This project will be conducted as four concurrent subprojects. Three subprojects will be directed at (1) demonstrating field performance of a semipermeable membrane devise (SPMD) to collect long-term integrated samples for semivolatile organics in air, (2) developing simple rapid methods for analyzing the SPMDs, and (3) developing rapid field or near field methods for analyzing chemical metabolites in urine. The fourth subproject will be a literature review to identify available but not currently used techniques for long-term integrated exposure measurements.
This work has been funded wholly or in part by the United States Environmental Protection Agency and this poster has been approved for publication. Mention of trade names or commercial products does not constitute endorsement or recommendation for use.