Household exposures to drinking water disinfection by-products: whole blood trihalomethane levels

Abstract

Exposure to drinking water disinfection by -products ( DBPs ) , such as trihalomethanes ( THMs ) , has been associated with bladder and colorectal cancer in humans. Exposure to DBPs has typically been determined by examining historical water treatment records and reconstructing study participants' water consumption histories. However, other exposure routes, such as dermal absorption and inhalation, may be important components of an individual's total exposure to drinking water DBPs. In this study, we examined individuals' exposure to THMs through drinking, showering, or bathing in tap water. Thirty -one adult volunteers showered with tap water for 10 min ( n = 11 ) , bathed for 10 min in a bathtub filled with tap water ( n = 10 ) , or drank 1 l of tap water during a 10 -min time period ( n = 10 ) . Participants provided three 10 ml blood samples: one sample immediately before the exposure; one sample 10 min after the exposure ended; and one sample 30 min ( for shower and tub exposure ) or 1 h ( for ingestion ) after the exposure ended. A sample of the water ( from the tap, from the bath, or from the shower ) was collected for each participant. We analyzed water samples and whole blood for THMs ( bromoform, bromodichloromethane, dibromochloromethane, and chloroform ) using a purge -and -trap / gas chromatography / mass spectrometry method with detection limits in the parts -perquadrillion range. The highest levels of THMs were found in the blood samples from people who took 10 -min showers, whereas the lowest levels were found in the blood samples from people who drank 1 l of water in 10 min. The results from this study indicate that household activities such as bathing and showering are important routes for human exposure to THMs.

Exposure to tap water during pregnancy

“…Storage of cold, tap water-based beverages and heating tap water to produce hot beverages reduce the concentrations of the volatile DBPs such as the trihalomethanes (Weisel et al, 1999 ). In addition, failure to account for dermal and inhalation exposures to DBPs is likely to lead to an underestimate of total exposure (Weisel and Chen, 1994;Backer et al, 2000 ). In this study, the use of private wells was not a source of misclassification since almost all tap water consumed at home and at work was from municipal supplies.…”

“…Dermal absorption or inhalation through showering, bathing, and swimming has been shown to be a significant source of DBP exposure ( Weisel and Jo, 1996;Backer et al, 2000 ). Both pregnant and non-pregnant women took daily showers of considerable length and had frequent extended contact with water through washing and cleaning activities.…”

Drinking Water Disinfection By-products, Genetic Polymorphisms, and Birth Outcomes in a European Mother–Child Cohort Study

“…Uptake of trihalomethanes (total dose log transformed to normalize) was estimated using a combination of modeled trihalomethanes, information on personal activities via ingestion, showering and bathing and uptake factors based on the literature [21][22][23] and in an earlier analysis in Spain. 9 Uptake factors used in the analysis for water ingestion were 0.0049 μg/μg/L for total trihalomethanes, 0.00490196 for chloroform and dibromochloromethane uptake factors were used for the three brominated trihalomethanes.…”

Assessing exposure in epidemiologic studies to disinfection by-products in drinking water: report from an international workshop.

“…Some work has been done in developing biomarkers for THMs in blood (28)(29)(30) and exhaled breath (31)(32)(33) and HAAs in urine (33)(34)(35). The studies on HAAs in urine (33-35) involved a crosssectional sampling design that precluded evaluation of intraindividual variability and limited the assessment of interindividual variability.…”