Carcinogenic Risk of Chlorinated Disinfection By-products in Water Treated by Enhanced Coagulation and Filtration Technology

Objective  To assess the carcinogenic risks of chlorinated disinfection by-products (Cl-DBPs) in treated water by using an enhanced coagulation and filtration technology.

Methods  Water samples were collected from the waterworks in Wuhu in 2012-2014. Eight Cl-DBPs were monitored. Based on the existing survey data on the aggregated exposure of children, adolescents, middle-aged and elderly in China, the carcinogenic risk was evaluated by the.Method recommended by US Environmental Protection Agency.

Results  The lifetime carcinogenic risk of three Cl-DBPs, bromodichloromethane (BDCM), dibromochloromethane (DBCM) and dichloroacetic acid (DCAA), were in the range of 10^-6~10^-4, and the rank of risks was BDCM > DBCM >DCAA. The major source of carcinogenic risk was from the genetic toxicity caused by BDCM. Except the carcinogenic risk of BDCM (1.08×10^-5) was just over the upper limit of tolerable risk (10^-5)recommended by the World Health Organization, the carcinogenic risk of DBCM and DCAA were at the range of 10^-6~10^-5, the carcinogenic risk of other 5 Cl-DBPs were less than 10^-6.

Conclusion  Based on the conventional process, waterworks could apply the enhanced coagulation and filtration technology for using Yangtze River water as water source; the lifetime cancer risks caused by Cl-DBPs in treated water can be controlled under the upper limit of tolerable risks.