Mutagenic drinking water and different levels of emerging micropollutants in Southern Brazil: A new challenge

This study investigated the presence of mutagenic compounds in raw and treated waters at four water treatment plants (WTP01 to WTP04), in southern Brazil. Samples were concentrated using Amberlite XAD4 resin and the acidic and neutral pH fractions tested by mutagenesis in Salmonella/microsome assay, using TA98, TA100 and YG7108 strains in presence and absence of metabolic activation (in vitro human S9). Mutagenesis in raw water was found only by strain TA98 at WTP03, with and without S9. In treated water, significant results were found for TA98 and TA100 strains, the latter being the most sensitive, with prevalence in acidic extract tests without S9. A chemical analysis was performed in the water samples, prioritizing the investigation of the presence and concentration of globally used Emerging Micropollutants (EMs). These compounds in water sources have the potential to contaminate drinking water due to the inefficiency of the conventional treatment employed and can generate disinfection by-products. WTP04 site had the highest total EMs in raw and treated waters, followed by WTP03 in treated water. These WTPs expressed an EMs removal capacity of 45% and only 23%, respectively. Some pharmaceuticals and caffeine showed the highest concentrations, and the latter was directly related to the disposal of domestic sewage in the aquatic ecosystem. The presence of EMs in water after treatment for all WTPs investigated suggests the importance of expanding guidelines that include EMs to establish better standards for the protection of aquatic life and better quality of the drinking water supplies.