Drinking water disinfection by-products: an Australian perspective

Disinfection of water supplies is of paramount importance for the prevention of waterborne diseases. Unfortunately, an unwanted side effect is the formation of by-products. Currently, chlorine and monochloramine are the only agents used to disinfect major drinking water supplies in Australia. Historically, some Australian waters have produced high concentrations of disinfection by-products (DBPs) upon chlorination. However, most water authorities in Australia do not routinely monitor DBP concentrations, with only a few analysing for THMs alone. Accordingly, there has been very little information available on the nature, distribution and typical concentrations of DBPs in Australian drinking waters. A number of analytical methods for the determination of DBPs were assessed and an analytical survey of 16 drinking waters from around Australia was conducted to determine their occurrence. Typically, DBP concentrations, with the exception of cyanogen chloride, were lowest in chloraminated waters. The survey revealed that for some waters, chloroacetic acid and chloral hydrate are the DBPs most likely to exceed the 1996 NHMRC Australian Drinking Water Guidelines.