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NHEXAS PHASE I MARYLAND STUDY--QA ANALYTICAL RESULTS FOR PESTICIDES IN REPLICATE SAMPLES
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Citation:
Description:
The Pesticides in Replicates data set contains the analytical results of measurements of up to 10 pesticides in 68 replicate (duplicate) samples from 41 households. Measurements were made in samples of indoor air, dust, soil, drinking water, food, and beverages. Duplicate samples for a small percentage of the total number of samples were analyzed to assess sample collection and analysis precision. In some cases (e.g., dust samples) there was also a sample homogeneity component in the precision measurement. Some samples are not amenable to duplicate sample collection and were not collected in this study. Duplicate sample collection and analysis procedures, which were part of the QA/QC protocols of the NHEXAS project, were the same as those used for the regular samples. The primary pesticides of interest included a-chlordane (CAS #5103-71-9 ), g-chlordane (CAS #12789-03-6), chlorpyrifos (CAS #2921-88-2), 4,4'-DDD (CAS #72-54-8), 4,4'-DDE (CAS #72-55-9), 4,4'-DDT (CAS #789-02-6), dieldrin (CAS #60-57-1), heptachlor (CAS #76-44-8), and malathion (CAS #121-75-5). Keywords: quality assurance; replicates; pesticides.
The National Human Exposure Assessment Survey (NHEXAS) is a federal interagency research effort coordinated by the Environmental Protection Agency (EPA), Office of Research and Development (ORD). Phase I consists of demonstration/scoping studies using probability-based sampling designs. The studies collected household environmental and personal samples for chemical analysis, and questionnaires were administered. The NHEXAS Phase I Questionnaires were organized into six modules for simplicity in administration (to minimize respondent burden and maximize participation rates at each step) and for collecting information that can be temporally related to the exposure, concentration, and/or biological measurements collected in NHEXAS: Descriptive, Baseline, Technician, Follow-up, Time and Activity diary, and Dietary diary (and follow-up). The NHEXAS-Maryland study sampled residences determined by a proportion-based sample of Baltimore and four adjacent counties and measured metals, pesticides, and polynuclear aromatic hydrocarbons (PAHs). The study was conducted by Harvard University, Emory University, Johns Hopkins University, and Westat. Data collection occurred up to six times over one year for the participating households. Analytical results were obtained under strict QA/QC requirements during collection, processing, and final deposition into databases.