Psychoactive pharmaceutical residues in the watersheds of Galicia (Spain).

OBJECTIVE To monitor the presence of pharmaceutical residues of 14 psychoactive drugs belonging to three therapeutic groups in the watersheds of Galicia (Spain). METHOD Five sewage treatment plants were selected in the main cities of Galicia. Thirteen psychoactive pharmaceutical compounds and one metabolite were chosen. In addition, tap water samples were taken from public places and private residences in the selected cities. RESULTS In all the water samples analyzed, the highest concentrations corresponded to the group of anxiolytics. In particular, high concentrations of lorazepam were found in river and tap water samples. CONCLUSIONS This investigation demonstrates the presence of psychoactive pharmaceuticals in the watersheds of the autonomous region of Galicia and the conversion of metabolites to parent compounds. This work also shows the need to increase environmental monitoring of watersheds and to improve sewage and drinking water treatment processes to remove these pharmaceuticals.