Occurrence of the pharmaceutical drug clofibric acid and the herbicide mecoprop in various Swiss lakes and in the North Sea

Clofibric acid (CA) and the herbicide mecoprop (MCPP) were detected in Swiss lakes from populated areas and in the North Sea in the low nanograms per liter range. Gas chromatography/mass spectrometry (GC/MS) and MS/MS were used to distinguish the two isomeric compounds (analyzed as the methyl esters). The concentrations of CA in the North Sea (1-2 ng/L) reach levels of those of "classical" environmental pollutants such as alpha- and gamma-hexachlorocyclohexane. The data suggest a high mobility of CA in the aquatic environment. The changed relative concentrations of CA and MCPP in the North Sea as compared to those in the lakes and in comparison to production figures indicate a much more persistent behavior for CA than for MCPP. The data also indicate that some pharmaceutical compounds need evaluation on ecotoxicological grounds in very much the same way as do agricultural chemicals.