Detection of mutagens in water-distribution systems after disinfection

This research examined the quality of water—before and after distribution—of four drinking-water production plants located
in Northern Italy, two of which collected water from local aquifers and two from the River Po. A battery of genotoxicity assays
for monitoring drinking-water was performed to assess the quality of the water produced by the treatment plants under study.
Three different sampling stations were selected at each plant, one right at the outlet of the treatment plant and two along with the
distribution pipelines. Raw river water was also sampled and analysed as a control. The water samples (500 l) were concentrated
on silica C18 cartridges and the extracts were tested in in vitro mutagenicity assays (Salmonella/microsome assay with strains TA
98 and TA 100; SOS Chromotest with Escherichia coli strain PQ37); gene conversion, point mutation and mitochondrial DNA
mutability assays with the diploid Saccharomyces cerevisiae strain D7 and a toxicity test using the bioluminescent bacterium Vibrio
fischeri (MicrotoxTM ).
The MicrotoxTM test and the mitochondrial DNA mutability assay showed the greatest sensitivity towards toxic or mutagenic
substances in thewater extracts considered. The results showthat this battery of short-term tests is applicable in the routine monitoring
of drinking-water quality before and after distribution.