Tracing Genotoxic N-DBPs After Medium Pressure UV Water Treatment by Nitrogen Labelling

Genotoxic nitro-organic byproducts are formed in water treatment when medium pressure ultraviolet technology is applied on nitrate containing water types. The genotoxicity was measured via the Ames test bioassay and converted into 4-nitroquinoline equivalents for preliminary risk assessment purposes, indicating the necessity for further identification of the genotoxic compounds. Using labelled N15-NO3 in bench scale experiments in reconstituted water with IHSS Pony Lake natural organic matter, allowed detection with LC-HR-MS of approximately hundred nitro-organic compounds in the 10–100 ng/L concentration. Analysis of full scale water treatment samples confirmed the bench scale experiments.