Screening of antimycotics in Swedish sewage treatment plants - Waters and sludge

Concentrations of six pharmaceutical antimycotics were determined in the sewage water, final effluent and sludge of five Swedish sewage treatment plants (STPs) by solid phase extraction, liquid/solid extraction, and liquid chromatography-electrospray tandem mass spectrometry. The antimycotics were quantified by internal standard calibration. The results were used to estimate national flows that were compared to predictions based on sales figures. Fluconazole was the only one of the six investigated antimycotics that was detected (at concentrations ranging from 90 to 140 ng L⁻¹) in both raw sewage water and final effluent. Negligible amounts of this substance were removed from the aqueous phase, and its levels were below the limit of quantification in all of the analyzed sludge samples. In contrast, clotrimazole, ketoconazole and econazole were present in all of the sludge samples, at concentrations ranging between 200 and 1000 μg kg⁻¹, dry weight. There were close correlations between the national measured and predicted antimycotic mass flows. Antimycotic fate analysis, based on sales figures, indicated that 53% of the total amount of fluconazole sold appeared in the final effluents of the STPs, while 1, 155, 35, 209 and 41% of the terbinafine, clotrimazole, ketoconazole, econazole and miconazole sold appeared in the digested dewatered sludge.