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NHEXAS PHASE I MARYLAND STUDY--QA ANALYTICAL RESULTS FOR METALS IN SPIKE SAMPLES
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The EPA does all it can to ensure that the identity of survey participants cannot be disclosed. All direct identifiers, as well as any characteristics that might lead to identifications, are omitted from the data. Any intentional identification or disclosure of a person or establishment violates the assurances of confidentiality given to the providers of the information. Therefore, users will (1) use the data in this study for statistical reporting and analysis only; (2) make no use of the identity of any person or establishment discovered inadvertently and will advise the HEDS Administrator of any such discovery; (3) will not link this data with individually identifiable data from other EPA or non-EPA data.
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Citation:
Description:
The Metals in Spikes data set contains the analytical results of measurements of up to 4 metals in 71 control samples (spikes) from 47 households. Measurements were made in samples of indoor and outdoor air, blood, and urine. Controls were used to assess recovery of target analytes from a sample media during storage, shipment, processing, and analysis. Controls were prepared by fortifying a suitable background-free matrix identical or similar to the sample being collected. Controls were prepared in the labs and shipped to the field site. They were then returned along with the samples. Controls were used for some sample media, with the controls deployed for a small percentage of the study participants. In several cases where there may not have been suitable media or means of fortification, controls were not collected. The samples were analyzed as part of the QA/QC protocols of the NHEXAS project. The primary metals of interest included arsenic (CAS #7440-38-2), cadmium (CAS #7440-43-9), chromium (CAS #7440-47-3), and lead (CAS #7439-92-1). Keywords: quality assurance; spikes; metals.
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.