Formation of genotoxic compounds by medium pressure ultraviolet treatment of pre-treated surface water and groundwater

To avoid by-product formation from chlorination and ozonation, application of MP UV technology has increased for disinfection and organic contaminant control. In nitrate rich waters MP UV forms the inorganic reaction product nitrite; however, harmful organic reaction product formation is not well documented. Initial genotoxicity research found no Ames test response in conventionally pre-treated IJssel Lake water. However, a significant response was found using synthetic quartz which exposes wavelengths < 240 nm. This research explores genotoxic compound formation by MP UV treatment of several water types, and examines the relation between Ames II test results and water constituents.;MP UV treatment increased the Ames test response of nitrate rich water in the presence of organic matter. A relationship between Ames test response and nitrite formation was found, indicating an important role of nitrate photolysis. An assessment with 4-nitroquinoline oxide (4-NQO) revealed a health impact is possible without post treatment.