Health Effects of Haloforms in Drinking Water and Strategies for Their Control

Abstract

The human population throughout history has been threatened by waterborne illnesses like typhoid fever and cholera. The disinfection of water supplies using chemical and physical intervention strategies has resulted in a dramatic decline in outbreaks of these epidemics. Water chlorination was and still is the most frequent used method of disinfection. The advances of water chlorination were unquestioned until the 1970s when Rook described the production of chloroform from humic acids and its subsequent identification in drinking water supplies. It was only the beginning and now additional classes of disinfection by-products (DBPs) such as alcohols, aldehydes, acids, etc., have been identified. The reaction between naturally occurring humic and fulvic acids in surface and ground water and disinfectants including chlorine, chloramine, chlorine dioxide and ozone, produces DBPs. However, the DBPs profile has to do with treatment methods. With the identification of these DBPs, the potential toxic effects from exposure to these organics is an interesting scientific area until today insufficient evidence exists regarding toxicity from animal testing for individual compounds and mixtures at concentrations found in water. United States Environmental Protection Agency (USEPA), taking into account the identification of carcinogenic compounds in drinking water, formed a regulation of these compounds, with initial efforts focusing on trihalomethanes (THMs). The goal of disinfection is to maximise protection from bacterial contamination, while minimising the formation of DBPs, by improving the quality of the raw water, using an alternative disinfectant, or removing organic contaminants and DBPs after they are formed during the treatment process.