Disinfection By-product - Health Effects

Health Effects

Epidemiological studies have looked at the associations between exposure to DBPs in drinking water with cancers, adverse birth outcomes and birth defects. Meta-analyses and pooled analyses of these studies have demonstrated consistent associations for bladder cancer and for babies being born small for gestational age, but not for congenital anomalies (birth defects). Early-term miscarriages have also been reported in some studies. The exact putative agent remains unknown, however, in the epidemiological studies since the number of DBPs in a water sample are high and exposure surrogates such as monitoring data of a specific by-product (often total trihalomethanes) are used in lieu of more detailed exposure assessment. The World Health Organization has stated that "the risk of death from pathogens is at least 100 to 1000 times greater than the risk of cancer from disinfection by-products (DBPs)" {and} the "risk of illness from pathogens is at least 10 000 to 1 million times greater than the risk of cancer from DBPs".