Comparison of trihalomethanes in tap water and blood

Trihalomethane (THM) concentrations in blood and tap water were measured for 50 women living in two locations with different bromide concentrations and disinfectant types. Blood samples were taken from each woman early in the morning prior to any major water-use activity and again immediately after showering. Each residence was sampled for THMs in tap water prior to the woman's shower. Cobb County, GA, tap water exhibited high THM concentrations composed primarily of chloroform. Corpus Christi, TX, tap water exhibited lower THM concentrations with significant proportions of brominated THMs. THMs in tap water and blood were compared using mole fraction speciation, extent of bromine incorporation, and correlation analysis. Results indicated that THMs in the blood rose significantly as a result of showering, that showering shifted the THM distribution in the blood toward that found in the corresponding tap water, and that THMs measured in the blood of women living in the two locations reflected species and concentration differences in their respective tap waters. In general, blood concentrations were not significantly correlated with tap water concentrations. This finding suggests that other factors, in addition to tap water concentrations, may be important in determining THM concentrations in the blood.