| Influence of Tap Water Quality and Household Water Use Activities on Indoor Air and Internal Dose Levels of Trihalomethanes John R. Nuckols,1 David L. Ashley,2 Christopher Lyu,3 Sydney M. Gordon,4 Alison F. Hinckley,1 and Philip Singer5 1Department of Environmental and Radiological Health Sciences, Colorado State University, Fort Collins, Colorado, USA; 2Emergency Response and Air Toxicants Branch, Centers for Disease Control and Prevention, Atlanta, Georgia, USA; 3Battelle, Centers for Public Health Research and Evaluation, Durham, North Carolina, USA; 4Battelle, Columbus, Ohio, USA; 5Department of Environmental Sciences and Engineering, University of North Carolina, Chapel Hill, North Carolina, USA Abstract
Individual exposure to trihalomethanes (THMs) in tap water can occur through ingestion, inhalation, or dermal exposure. Studies indicate that activities associated with inhaled or dermal exposure routes result in a greater increase in blood THM concentration than does ingestion. We measured blood and exhaled air concentrations of THM as biomarkers of exposure to participants conducting 14 common household water use activities, including ingestion of hot and cold tap water beverages, showering, clothes washing, hand washing, bathing, dish washing, and indirect shower exposure. We conducted our study at a single residence in each of two water utility service areas, one with relatively high and the other low total THM in the residence tap water. To maintain a consistent exposure environment for seven participants, we controlled water use activities, exposure time, air exchange, water flow and temperature, and nonstudy THM sources to the indoor air. We collected reference samples for water supply and air (pre-water use activity) , as well as tap water and ambient air samples. We collected blood samples before and after each activity and exhaled breath samples at baseline and postactivity. All hot water use activities yielded a 2-fold increase in blood or breath THM concentrations for at least one individual. The greatest observed increase in blood and exhaled breath THM concentration in any participant was due to showering (direct and indirect) , bathing, and hand dishwashing. Average increase in blood THM concentration ranged from 57 to 358 pg/mL due to these activities. More research is needed to determine whether acute and frequent exposures to THM at these concentrations have public health implications. Further research is also needed in designing epidemiologic studies that minimize data collection burden yet maximize accuracy in classification of dermal and inhalation THM exposure during hot water use activities. Key words: biomarkers, chlorination, disinfection by-products, exposure, trihalomethane, water use. Environ Health Perspect 113:863-870 (2005) . doi:10.1289/ehp.7141 available via http://dx.doi.org/ [Online 24 March 2005]
Address correspondence to J.R. Nuckols, Environmental Health Advanced Systems Laboratory, Department of Environmental and Radiological Health Sciences, Colorado State University, Fort Collins, CO 80523-1681 USA. Telephone: (970) 491-7295. Fax: (970) 491-2940. E-mail: jnuckols@colostate.edu We thank C. Wilkes for his assistance in the design and implementation of the field study ; M. Brinkman, M. Holdren, and W. Keigley (Battelle) for air and breath sample analysis ; R. Dietz (Brookhaven National Laboratory) for assisting in tracer analysis ; B. Blount, M. Bonin, L. Silva, M. Smith, and C. Dodson (CDC) for assisting in blood analysis ; E. DePaz (University of North Carolina at Chapel Hill) for water analysis support ; and our nurses and field data collection staff for their hard work. Funding for this project and manuscript preparation was provided in part by the National Center for Environmental Health (CDC) , the American Water Works Association Research Foundation, and the National Institutes of Health, National Cancer Institute, Occupational and Environmental Epidemiology Branch. The authors declare they have no competing financial interests. Received 31 March 2004 ; accepted 24 March 2005.
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