The anti-inflammatory drugs diclofenac, naproxen and ibuprofen are found in the bile of wild fish caught downstream of a wastewater treatment plant.

Pharmaceutical residues are ubiquitous in rivers, lakes, and at coastal waters affected by discharges from municipal wastewater treatment plants. In this study, the presence of 17 different pharmaceuticals and six different phase I metabolites was determined in the bile of two wild fish species, bream (Abramis brama) and roach (Rutilus rutilus). The fish were caught from a lake that receives treated municipal wastewater via a small river. Prior to analyses, the bile content was enzymatically hydrolyzed to convert the glucuronide metabolites into the original pharmaceuticals or phase I metabolites. The solid phase extracts of hydrolyzates were analyzed by liquid chromatography-tandem mass spectrometry (LC-MS/MS) in the multiple reaction monitoring mode. The anti-inflammatory drug naproxen could be detected in all the six bream and roach bile samples. Diclofenac was found in five of the bream and roach samples, while ibuprofen was detected in three bream and two roach samples. The observed bile concentrations of diclofenac, naproxen, and ibuprofen in bream ranged from 6 to 95 ng mL(-1), 6 to 32 ng mL(-1), and 16 to 34 ng mL(-1), respectively. The corresponding values in roach samples ranged from 44 to 148 ng mL(-1), 11 to 103 ng mL(-1) and 15 to 26 ng mL(-1), respectively. None of the other studied compounds could be detected. The study shows that pharmaceuticals originating from wastewater treatment plant effluents can be traced to the bile of wild bream and roach living in a lake where diclofenac, naproxen, and ibuprofen are present as pollutants.