Licit and Illicit Drugs in Urban Wastewater in Cyprus

Two multi-residue methods based on off-line solid phase extraction followed by LC-MS/MS have been applied in samples collected from three sewage treatment plants for the identification and quantification of licit and illicit drugs. The occurrence of the drugs in wastewater appears to be influenced by both the operational parameters of each plant and their consumption in the area served by the corresponding plant. Generally, the present study demonstrated that both licit and illicit drugs were found in the effluent wastewater of all urban wastewater treatment plants; a fact suggesting that they are bioresistance. These compounds were determined in relatively high concentrations (licit drugs: below limit of detection (BLD) to 5520 ng/L and illicit drugs: BLD to 5815 ng/L) in all effluent wastewater samples monitored in this study. The major groups of licit drugs detected in the effluents were antibiotics, b-blockers, analgesics, and non-steroidal-anti-inflammatory drugs suggesting that these compounds show a noticeable resistance against the biological treatment applied. The concentrations of antibiotics and b-blockers in the effluents ranged from ca. 4 to 200 ng/L and 40 to 500 ng/L, respectively. Concerning the illicit drugs, cocaine and its metabolite benzoylecgonine were detected in almost all effluent samples with median values of 1 and 3 ng/L, respectively.