Exposure of Children to Chloroform During Bathing

Abstract

P-221 Introduction: Trihalomethanes (THMs) comprise up to 50% of the total weight of all chlorination byproducts present in drinking water. Among THMs, the most important in quantitative terms is most often chloroform (CHCl3.), which has been classified as possibly carcinogenic to humans by the International Agency for Research on Cancer. Humans can be exposed to CHCl3 not only through ingestion, but also through inhalation and dermal absorption. This study was carried out to verify, under realistic conditions, the internal doses of CHCl3 in children generated by taking a bath. Methods: A total of 19 children (10 boys, 9 girls) aged between 4 and 11 years old and living in 19 homes were recruited to participate in the study. The concentration of CHCl3 in exhaled breath of each subject was measured before and immediately after the bath, and 15 minutes and 30 minutes after bathing. The measurement preceding the bath was used to evaluate the participants' baseline level, and the difference between the alveolar CHCl3 concentration after and before the bath indicated the internal dose induced by bathing. Four ambient air samples were collected to document ambient air chloroform levels. A pre-bath sample was collected in the living room that provided the background level for the home. The three other samples were collected midway through the bath, and during the two subsequent 15-minute periods. CHCl3 concentrations in water of participants' homes were determined in the cold tap water as well as in the bath water. Different variables (age, body weight, height, concentrations of CHCl3 in ambient air and in the water) were examined in relation to the internal dose of CHCl3 using multiple regression models. Results: Mean concentrations of CHCl3 in bathroom air and bath water were 50.6 μg/m3 and 23.8 μg/L, respectively. Alveolar air CHCl3 concentrations increased by an average of 13.7 μg/m3 immediately after bathing and returned to background level 30 minutes after bathing. Only CHCl3 concentration in the air during the bath was significantly associated with the internal dose. Discussion and Conclusions: To our knowledge, this study is the first to document the exposure of children to CHCl3 through bathing, which is likely one of the main domestic source of exposure in children. The data presented here will be useful to assess health risks resulting from chloroform exposure in populations exposed to low levels of chloroform in their tap water.