Patterns of water use and exposure to trihalomethanes among children in Spain.

Few studies characterizing trihalomethane (THM) exposure or examining potential health effects were conducted in children. The present study describes patterns of water use in children as a source of THM exposure, and estimates the daily THM uptake and the relative contribution of each pathway of exposure. A cross-sectional population-based study was conducted in children 9-12 years of age in Sabadell, Catalonia, Spain (N=2037). We collected individual information on ingestion, frequency and duration of showering, bathing and swimming, source of drinking water, age, sex and parental education. Chloroform, dibromochloroform, bromodichloroform and bromoform in tap, bottled and swimming pool water were measured. The daily chloroform and brominated THM uptakes were estimated combining environmental levels with individual water activities using algorithms reported in the literature. Among the studied group, 80% of children drank bottled water and 20% regularly attended swimming pools. Mean THM concentration in bottled, tap and chlorinated pool water were, respectively, 0.3, 117 and 92 microg/L. Brominated THM predominated in the tap water (84% of total THM) and chloroform predominated in the swimming pool (84% of total THM). Children attending swimming pools had four times higher THM uptake compared to non-swimmers (p-value<0.05). Showering was the main pathway of exposure for non-swimmers. Girls and children with low parental education had a higher THM uptake (p-value<0.05) as they reported taking longer showers and more frequent baths. In conclusion, total and specific THM uptake varied considerably with the personal water uses among children. As drinking water was mainly bottled and bathing was infrequent, showering and swimming in pools were the main pathways of THM exposure. Specific water uses among children slightly differed by sociodemographic characteristics.