AWWA WQTC64091

Drinking water disinfection processes, especially those utilizing chlorine, can increase the genotoxic activity of water through the production of disinfection byproducts (DBPs). Genotoxicity is a measure of the amount of damage a substance can cause to a DNA molecule and is a parameter of interest due to its strong correlation to carcinogenicity. Commonly formed DBPs such as trihalomethanes (THMs) and haloaceticacids (HAAs) can be quantified by analytical techniques, but many other unidentified byproducts can also be formed. Biological assays may be used to measure the total genotoxic effect of these byproducts, including those which cannot be identified. The goal of the current study is to compare the genotoxicity of waters treated with chemical disinfectants, UV (low and medium pressure both alone and with H₂O₂), and UV followed by chemical disinfectants including chlorine, chloramines and chlorine dioxide. A range of source waters, exhibiting different watershed characteristics, are being examined. Genotoxicity of the disinfected samples as monitored using the Ames test, the Microtox test and the SOS-Chromotest provide complimentary data sets. DBP concentrations (THMs and HAA9) are also compared to these results. This information allows for an assessment of the potential for unidentified genotoxic compounds to form during specific disinfection strategies as well as providing insight into how they can be minimized. Results to date indicate a weak genotoxic potential can be quantified for several of the disinfection scenarios. Includes 12 references, table, figures.