Multi-pathway Risk Assessment of Trihalomethanes Exposure in Drinking Water Supplies

Disinfection is the last step in the water treatment processes for the protection of public health. In India, chlorine is used as the primary disinfectant because of its low cost and convenience for application in water purification. However, chlorination results in formation of trihalomethanes (THMs) in drinking water which can pose severe health threat due to their potential carcinogenicity. In recent decades, various epidemiological studies have been conducted to determine the relationship between THMs and different health outcomes e.g., cancers and reproductive outcomes (Hrudey 2009). Llopis-Gonzalez et al. (2011) suggested that exposure to THMs increase the risk of bladder, colon, rectum, leukemia, stomach and rectal cancers. The results of animal studies have demonstrated that liver, kidney and intestinal tumorigenesis are associated with chronic ingestion of THMs (Yang et al. 2000). Since THMs are the most prevalent and well documented disinfection by product (DBP) compounds in drinking water, they are generally considered as indicators of DBP exposure in epidemiological investigations.