| Changes in Breath Trihalomethane Levels Resulting from Household Water-Use Activities Sydney M. Gordon,1 Marielle C. Brinkman,1 David L.
Ashley,2 Benjamin C. Blount,2 Christopher Lyu,3 John
Masters,3 and Philip C. Singer4 1Battelle Memorial Institute, Columbus, Ohio, USA; 2National
Center for Environmental Health, Emergency Response and Air Toxicants Branch,
Centers for Disease Control and Prevention, Atlanta, Georgia, USA; 3Centers
for Public Health Research and Evaluation, Battelle Memorial Institute, Durham,
North Carolina, USA; 4Department of Environmental Sciences and Engineering,
University of North Carolina-Chapel Hill, Chapel Hill, North Carolina, USA Abstract
Common household water-use activities such as showering, bathing, drinking, and washing clothes or dishes are potentially important contributors to individual exposure to trihalomethanes (THMs) , the major class of disinfection by-products of water treated with chlorine. Previous studies have focused on showering or bathing activities. In this study, we selected 12 common water-use activities and determined which may lead to the greatest THM exposures and result in the greatest increase in the internal dose. Seven subjects performed the various water-use activities in two residences served by water utilities with relatively high and moderate total THM levels. To maintain a consistent exposure environment, the activities, exposure times, air exchange rates, water flows, water temperatures, and extraneous THM emissions to the indoor air were carefully controlled. Water, indoor air, blood, and exhaled-breath samples were collected during each exposure session for each activity, in accordance with a strict, well-defined protocol. Although showering (for 10 min) and bathing (for 14 min) , as well as machine washing of clothes and opening mechanical dishwashers at the end of the cycle, resulted in substantial increases in indoor air chloroform concentrations, only showering and bathing caused significant increases in the breath chloroform levels. In the case of bromodichloromethane (BDCM) , only bathing yielded a significantly higher air level in relation to the preexposure concentration. For chloroform from showering, strong correlations were observed for indoor air and exhaled breath, blood and exhaled breath, indoor air and blood, and tap water and blood. Only water and breath, and blood and breath were significantly associated for chloroform from bathing. For BDCM, significant correlations were obtained for blood and air, and blood and water from showering. Neither dibromochloromethane nor bromoform gave measurable breath concentrations for any of the activities investigated because of their much lower tap-water concentrations. Future studies will address the effects that changes in these common water-use activities may have on exposure. Key words: biomarkers, breath analysis, disinfection by-products, exposure, trihalomethane, water use. Environ Health Perspect 114:514-521 (2006) . doi:10.1289/ehp.8171 available via http://dx.doi.org/ [Online 15 November 2005]
Address correspondence to S.M. Gordon, Battelle Memorial Institute, 505 King Ave., Columbus, OH 43201-2693 USA. Telephone: (614) 424-5278. Fax: (614) 424-3638. E-mail: gordon@battelle.org We thank M. Holdren and W. Keigley (Battelle) for air and breath sample analysis ; M. Bonin, L. Silva, M. Smith, and C. Dodson (Centers for Disease Control and Prevention) for assisting in blood analysis ; E. DePaz (University of North Carolina-Chapel Hill) for water analysis support ; and our nurses and field data collection staff for their hard work. We also thank R. Lordo (Battelle) for valuable statistical advice. Funding was provided by the Centers for Disease Control and Prevention through contract 200-98-0102 to Battelle Memorial Institute. The authors declare they have no competing financial interests. Received 4 April 2005 ; accepted 15 November 2005.
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