OCCURRENCE AND FORMATION OF N-NITROSAMINES AS DISINFECTION BY-PRODUCTS DURING WATER DISINFECTION

摘要

The disinfection of drinking water has resulted in the dramatic reduction and elimination of waterborn diseases, such as cholera and typhoid. It is essential for the protection of public health to perform and maintain proper water disinfection processes. However, unintended disinfection by-products (DBPs) are produced because the disinfectants themselves, such as chlorine, chloramines and chlorine dioxide, can react with naturally occurring materials in the water. Over 600 DBPs have been reported. Most research on DBPs has focused on regulated DBPs, which include trihalomethanes (THMs), haloacetic acids (HAAs), bromate and chlorite; however, the existing epidemiological studies on these known DBPs have failed to produce a truly plausible toxicological explanation for the relative cancer risk and adverse health effects estimated. It is suspected that many other unidentified DBPs may play more important roles in the adverse health effects observed.