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EXPOSURE ASSESSMENT METHODS DEVELOPMENT PILOTS FOR THE NATIONAL CHILDREN'S STUDY
Citation:
FORTMANN, R. C., S. E. FENTON, AND J. J. QUACKENBOSS. EXPOSURE ASSESSMENT METHODS DEVELOPMENT PILOTS FOR THE NATIONAL CHILDREN'S STUDY. Presented at National Children's Study, Washington, DC, November 29 - 30, 2005.
Description:
Accurate exposure classification tools are needed to link exposure with health effects. EPA began methods development pilot studies in 2000 to address general questions about exposures and outcome measures. Selected pilot studies are highlighted in this poster. The “Literature Review for Integrated Long-Term Sampling Methods” was conducted because single point samples do not adequately describe exposure events; hence, knowledge of exposure over time is needed. The focus of the review was on methods/instruments for exposure classification or long-term monitoring of chemicals in air, water, soil, and dust. Chemical classes included volatile organic compounds, semivolatile organic compounds, pesticides and metals. The review provides information on matrix, method type, method performance, chemicals, detection limits, burden, and estimates of analytical costs. A pilot study, titled “Demonstration of Low-Cost, Low-Burden, Exposure Monitoring Strategies for Use in the National Children’s Study,” was conducted to develop and demonstrate relevant exposure measurement strategies that can be used in a longitudinal epidemiological study including remote data collection by study participants. The approach included evaluation of readily available and commonly used methods, instruments, and techniques over a 12 month period. The study demonstrated that participants could effectively collect many types of environmental and biological samples but had difficulty with more complex sampling methods. Another pilot study addressed “Methods Advancement for Milk Analysis.” The objective of this study was to develop and evaluate methods for collection, preservation, storage, and analysis of human breast milk samples. In addition, blood, saliva, and urine samples were assessed as potential surrogate media. The approach included using commonly available breast pumps and standard collection containers and preservatives. Method verification and development studies with fresh and frozen human milk samples were conducted for a variety of chemical contaminants. Chemical measures in milk were compared with urine, saliva, and serum. Preliminary analysis of study results determined the appropriate sample collection and preservation techniques. Participant recruitment was best accomplished through office managers and nurses in doctor’s offices. A third pilot study focused on “Evaluation of Disposable Diapers for Measurement of Pesticide Metabolites and Creatinine in Urine.” The objective was to evaluate methods of using disposable diapers for collection of infant/toddler urine samples for analysis of metabolites and creatinine. A laboratory study evaluated an extraction and analysis method for measuring metabolites of organophosphate and pyrethroid pesticides. The results demonstrated that disposable diapers can be used to collect urine samples for pesticide analysis with acceptable analytical performance. Diapers could be stored for short time periods and shipped at ambient temperatures without sample degradation. These studies provide the National Children’s Study with additional information on exposure methods that can be more accurately and efficiently used to evaluate environmental exposures of children at different ages and stages of development.