Pharmaceutical residues in hospital and urban wastewaters: Occurrence, removal and potential risk assessment

The presence of ten pharmaceutical compounds (bupropion, venlafaxine, mirtazapine, sertraline, citalopram, caffeine, triclosan, carbamazepine, diazepam, clozapine) which belong to different treatment categories was studied in one hospital and three urban WWTPs in north and northwestern Greece. The pharmaceuticals have been selected due to their high usage rate but also because of their proven presence in both wastewater treatment plants and aquatic environments. Analytical methodology was based on gas chromatography coupled to mass spectrometry (GC-MS) detection after the application of a solid phase extraction (SPE) step. In addition, elimination of these compounds in the WWTPs was assessed as well as their ecotoxicological impact on the aquatic environment was estimated by means of risk quotient (RQ). The results showed that the most often detectable compounds were caffeine, triclosan and venlafaxine. High concentration levels of caffeine, up to 22142.1 ng/L were found, while removal rates were up to 99 %. In addition, high levels of acute and chronic toxicity were observed for triclosan (RQ>1).