Citation:

Thomas, D., E. Hudgens, AND J. Rogers. Biological and behavioral modifiers of urinary arsenic metabolic profiles in a U.S. population. Presented at Society of Toxicology, Phoenix, AZ, March 23 - 27, 2014.

Impact/Purpose:

This abstract describes the effect of biological and behavioral factors on the urinary excretion of inorganic and its methylated metabolites in an adult population in Churchill County, Nevada, in which arsenic in drinking water is a major source of exposure. Both biological and behavorial factors are found to affect the profile of arsenicals on urine in this population.

Description:

Biological and behavioral modifiers of urinary arsenic metabolic profiles in a U.S. population David J. Thomas – ISTD, NHEERL Edward F. Hudgens – EHPD, NHEERL John Rogers - Westat Relations between intensity of arsenic exposure from home tap water and levels of inorganic As (iAs) and its mono- (MAs) and di-methylated (DMAs) metabolites were examined in urine from 903 individuals 45 years of age or older who resided in Churchill County, Nevada, continuously for 5 or more years before enrollment. Over a wide range of exposures (home tap water supplies contained 3 to 1200 µg of As per liter), concentrations of iAs, MAs, and DMAs strongly correlated with concentrations of As in home tap water. However, percentages of the summed iAs, MAs, and DMAs concentrations in urine accounted for by each species were unaffected by As concentration in home tap water, suggesting that capacity for formation and excretion of methylated metabolites was not exceeded in this population. Mean urinary iAs, MAs, and DMAs concentrations were significantly lower (P<0.001) in urine of women than in men; women had significantly lower iAs and MAs (P<0.005) and significantly higher DMAs percentages (P<0.0001) in urine than men. Age did not affect concentration of any arsenical in urine, although there were significant age-related trends for decreased iAs percentage (P<0.0002) and for increased DMAs percentage (P<0.01). Body mass index (BMI) did not affect iAs, MAs, or DMAs levels in urine but BMI was significantly associated (P<0.01) with lower percentage MAs and increased percentage DMAs in urine. Smoking status (assessed by urinary cotinine levels was associated with significant trends for urinary iAs, MAs, or DMAs concentrations and for percentages of iAs, MAs, or DMAs (P<0.05). These results indicate that among older Americans with a wide range of exposure to iAs from home tap water, both biological factors (gender, age, BMI) and behavioral (smoking) factors can affect the profiles of arsenicals found in urine. These modifiers may contribute to interindividual and interpopulation variation in response to chronic exposure to As from water and other media. (This abstract does not reflect U.S. Environmental Protection Agency policy.) December 12, 2013

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