Occurrence of drugs in German sewage treatment plants and rivers

The occurrence of 32 drug residues belonging to different medicinal classes like antiphlogistics, lipid regulators. psychiatric drugs, antiepileptic drugs, betablockers and beta(2)-sympathomimetics as well as five metabolites has been investigated in German municipal sewage treatment plant (STP) discharges, river and stream waters. Due to the incomplete removal of drug residues during passage through a STP, above 80% of the selected drugs were detectable in at least one municipal STP effluent with concentration levels up to 6.3 mu g l(-1) (carbamazepine) and thus resulting in the contamination of the receiving waters. 20 different drugs and 4 corresponding metabolites were measured in river and stream waters. Mainly acidic drugs like the lipid regulators bezafibrate, gemfibrozil, the antiphlogistics diclofenac, ibuprofen, indometacine, naproxen, phenazone and the metabolites clofibric acid, fenofibric acid and salicylic acid as well as neutral or weak basic drugs like the betablockers metoprolol, propranolol and the antiepileptic drug carbamazepine were found to be ubiquitously present in the rivers and streams, mostly in the ng l(-1)-range. However, maximum concentrations were determined up to 3.1 mu g l(-1) and median values as high as 0.35 mu g l(-1) (both bezafibrate). The drugs detected in the environment were predominantly applied in human medicine. It can therefore be assumed that the load of municipal STP effluents in the surface water highly influences the contamination. Due to their wide spread presence in the aquatic environment many of these drugs have to be classified as relevant environmental chemicals. (C) 1998 Elsevier Science Ltd. All rights reserved.