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As part of the National Human Exposure Assessment Survey,a multistage sampling was used to estimate and compareexposures and risks associated with drinking water for twogroups - the population of Arizona and that of border communities.There had been some concern that the border communities'exposures would be higher than those of other parts of the statebecause of their proximity to Mexico, where environmental qualitymay not be as high a priority as it is in the United States.The two study populations were further categorized by gender,age, ethnicity, education, income, and building structure type andyear of construction. For these subgroups, the study estimated andcompared risks for arsenic, 1,3-butadiene, chloroform, chromium,1,2-dichloroethane, dichloromethane, lead, nickel, and toluene. Foralmost all of the sample subjects, residue concentrations werebelow the drinking water guideline values of both Arizona and theUS Environmental Protection Agency. Of the metals studied,arsenic was the only one with a population carcinogenic risk abovethe acceptable level of 1.0E-6. Contrary to expressed concerns,average daily exposures and associated risks were estimated to besmaller in the border communities than in the Arizona population.For utilities, one finding deserving further study was that risksfrom tap water were estimated to be greater than risks fromnontap water. Further research may be warranted to uncover thecauses for these elevated risks. Includes 26 references, tables, figure.

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Edition: Vol. 95 - No. 7 Published: 07/01/2003 Number of Pages: 13File Size: 1 file , 370 KB