Chlorination By‐products

Abstract

Disinfection of drinking water is considered one of the most successful public health interventions, effectively eliminating various waterborne diseases from many parts of the world. Chlorination is used for primary and secondary disinfection of drinking water and remains the predominant disinfectant choice worldwide. A disadvantage of chlorine and other disinfectants is their ability to react with organic and inorganic matter in water to form disinfection by‐products (DBPs). Teratogenic and carcinogenic effects have been detected in toxicological studies of DBPs, and epidemiological studies have also reported associations between DBP exposures and carcinogenic, reproductive, and developmental endpoints. Despite recent analytical improvements, many DBPs remain unidentified. The trihalomethanes are the most studied and regulated DBPs, although drinking water regulations and guidelines have been developed for several other DBPs. Exposure to DBPs can occur through ingestion, inhalation, and dermal contact depending on factors such as volatility and water usage behavior. For example, exposure to the volatile trihalomethanes can occur through all three routes of exposure, while exposure to nonvolatile haloacetic acids is primarily through ingestion. While the potential health effects associated with DBPs remain unclear, individual exposures can be reduced via point‐of‐use treatment (e.g., boiling or filtering water) prior to consumption.