Occurrence and risk assessment of pharmaceutically active compounds in water supply systems in Brazil.

The presence of pharmaceutically active compounds (PhACs) in water supply systems has been generating great concern about their effects on the environment and human health. Twenty-eight PhACs were monitored during one year in four Brazilian water sources, aiming to understand the factors that influence their occurrence and removal in conventional drinking water treatment plants (DWTPs) and to assess the environmental and human health risks. Trace levels of PhACs were detected in surface and drinking water in all assessed water sources. Effects of seasonality and socioeconomic aspects were observed in PhACs occurrence, like their higher concentrations during winter and in locales with higher values of gross domestic product per capita and human development index. Betamethasone, prednisone, and fluconazole were the most commonly detected PhACs, and also presented the highest concentrations. However, they were not related to toxicological risks. Nonetheless, all surface waters were subject to toxicological risk owing to at least one PhAC. PhACs related to the highest toxicological risks were loratadine, atorvastatin, norfloxacin, caffeine, and ranitidine, however, all these PhACs presented low quantification frequency. DWTPs capacity to remove PhACs was only partial, so treated water was still contaminated with these compounds. Furthermore, atorvastatin presented a margin of exposure below 100, indicating possible risk for public health. Thus, additional advanced treatment steps should be considered to improve PhACs removal during drinking water treatment.