Urinary Levels of Trichloroacetic Acid, a Disinfection By-Product in Chlorinated Drinking Water, in a Human Reference Population Antonia M. Calafat, Zsuzsanna Kuklenyik, Samuel P. Caudill, and David L. Ashley Division of Laboratory Sciences, National Center for Environmental Health, Centers for Disease Control and Prevention, Atlanta, Georgia, USA Abstract Trichloroacetic acid (TCAA) , a known mouse liver carcinogen and a possible human carcinogen, is found in chlorinated drinking water. We measured TCAA in archived urine samples from a reference population of 402 adults using isotope-dilution high-performance liquid chromatography-tandem mass spectrometry. TCAA was detected in 76% of the samples examined at concentrations ranging from < 0.5 µg TCAA/L to more than 25 µg/L ; the 90th percentile concentration was 23 µg/L (22 µg TCAA/g creatinine) ; and the geometric mean and median concentrations were 2.9 µg/L (2.6 µg/g creatinine) and 3.3 µg/L (3.2 µg/g creatinine) , respectively. The frequency of detection of TCAA in urban areas was higher than in rural areas (p = 0.00007) , and sex and place of residence (i.e., urban vs. rural) were found to have a significant interaction in modulating the levels of TCAA (p = 0.012) . Urban residents had higher mean levels of TCAA (men, 5.3 µg/L, 3.8 µg/g creatinine ; women, 2.9 µg/L, 2.8 µg/g creatinine) than did rural residents (men, 2.2 µg/L, 1.7 µg/g creatinine ; women, 2.6 µg/L, 2.7 µg/g creatinine) . The higher frequency of detection of TCAA in urban than in rural areas and higher levels of TCAA among urban than among rural residents may reflect the fact that urban residents use primarily chlorinated water from public water supplies, whereas those in rural areas are more likely to obtain water from private wells, which typically are not chlorinated. Key words: exposure, human, trichloroacetic acid, urine. Environ Health Perspect 111:151-154 (2003) . doi:10.1289/ehp.5644 available via http://dx.doi.org/ [Online 28 October 2002] The full version of this article is available for free in HTML or PDF formats. |