Occurrence of environmentally relevant pharmaceuticals in Italian drinking water treatment plants

The occurrence and seasonal distribution of 14 pharmaceutical substances of different classes were investigated in two drinking water treatment plants (DWTPs) supplied by the two main Italian rivers, the Po and the Adige (Northern Italy). The therapeutic categories of the selected pharmaceuticals included anti-inflammatory drugs, -blockers, lipid regulators, diuretics, antiepileptics, antibiotics and a steroidal hormone. The named compounds were assessed in samples collected from the river water inlet and after each purification stage (sand filtration, ozone treatment, granular active carbon (GAC)). Six of the 14 selected pharmaceuticals were found in all analysed samples, with concentration levels ranging from 1 ng l1 for atorvastatin to 69 ng l1 for atenolol in the drinking water produced. The granular active carbon stage resulted the most efficient in eliminating the examined chemicals from the water (removal range: 12–95%, average: 68%), while the sand filtration stage resulted the least effective treatment (removal range: 4–37%, average: 13%). The observed differences between winter and summer conditions, in terms of residual concentrations and number of detected analytes, seemed to depend mainly on the quality of the river water supplies. To the best of our knowledge, these are the first reported data on the presence of pharmaceuticals in drinking water obtained from the water treatment of these two rivers.