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CHURCHILL COUNTY, NEVADA ARSENIC STUDY: WATER CONSUMPTION AND EXPOSURE BIOMARKERS
HUDGENS, E. E., P. POWELL, AND J. ROGERS. CHURCHILL COUNTY, NEVADA ARSENIC STUDY: WATER CONSUMPTION AND EXPOSURE BIOMARKERS. Presented at International Society of Exposure Assessment Annual Meeting, Tucson, AZ, October 30 - November 03, 2005.
The US Environmental Protection Agency is required to reevaluate the Maximum Contaminant Level (MCL) for arsenic in 2006. To provide data for reducing uncertainties in assessing health risks associated with exposure to low levels (<200 g/l) of arsenic, a large scale biomarker study was completed in Churchill County, NV (population 29,000) in September 2002. The Churchill County population represents the largest U.S. population in a discrete geographic area exposed to arsenic levels higher than the previous standard of 50 g/l and has documented drinking water arsenic levels ranging from ?not detectable? to over 500 g/l. The county seat and largest community, Fallon (population 8,000), had arsenic levels of approximately 100 g/l in its public drinking water supply. Data collection has been completed on 906 twenty-year residents of Churchill County that were 45 years of age or older. A third of the study participants were recruited from within the Town of Fallon, while other participants were selected from areas with historical drinking water arsenic concentrations below the new standard of 10 g/l and over 100 g/l.
Each participant was asked to provide a blood, urine, toe nail and water sample. Additionally, all participants completed an odor identification test (olfactory sensitivity) and a questionnaire on diet, water consumption and health history. The urine and water samples have been evaluated for total arsenic. Measurement of arsenite, arsenate, monomethylarsonic acid (MMA), and dimethylarsinic acid (DMA) in urine provided a direct measure of an individual?s exposure and arsenic metabolism. The blood sample was evaluated for glycosylated hemoglobin (diabetes) on site. Sample and data analysis are on-going. Preliminary results on relationship between total urinary arsenic, water consumption, and the arsenic concentration of the water source as well as the metabolite profile will be presented.
(This abstract does not necessarily reflect EPA policy).