Customer Reviews

The Health Effects and Occurrence of Disinfection By-Products

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Research today does not come cheaply - especially when projects have involved extensive and prolonged data collection and analysis around substances which are difficult to identify, costly to quantify and whose behaviour is poorly understood. This Report on Disinfection By-Products (DBPs) is a good example. Furthermore, it talks about carcinogenicity, it concerns drinking water and it looks at an ever increasing number of familiar and newly identified DBPs.

To quote directly from the Report: Risks projected from epidemiological studies of chlorinated drinking water and risks projected from toxicological studies in animals are quite different, both qualitatively and quantitatively. Results of epidemiological studies identify a high level of risk from bladder cancer and to a lesser extent, colon cancer in humans consuming chlorinated drinking water (as many as 10,000 cases per year). In contrast, among the DBPs that have been selected for toxicological studies, risk has been identified for liver, kidney and colon cancer, but collectively at much lower levels of estimated risk than for epidemiological studies.

The difficulty arises because the epidemiological studies available cannot establish causality, in part because no bladder carcinogen has been found in toxicological studies of chlorination by-products. On the other hand, only a handful of the by-products produced in chlorination have been studied toxicologically. Thus, the basis of this difference is the critical question related to whether or not chlorination of drinking water needs to be substantially modified or discontinued as a method of disinfecting drinking water.

Included in this Report is a new updated review of DBPs, a synopsis of occurrence and available toxicological data with a notable increase in the sophistication of the available data over material previously published. To assist readers, a chapter is provided to facilitate a better understanding of how the decision-making process for establishing safe levels for chemicals has changed in recent years, especially with regard to carcinogens and of the use of epidemiological data. Also included are chapters devoted to both practical considerations for water treatment plant operators and ways to communicate effectively with the water consuming public about drinking water issues. - Reviewer - Australian Water Association