Occurrence of 40 pharmaceutically active compounds in hospital and urban wastewaters and their contribution to Mahdia coastal seawater contamination

In the present study, the occurrence of 40 pharmaceuticals belonging to several therapeutic groups was investigated for the first time in hospital effluent, wastewater treatment plant influent and effluent, and seawater in Mahdia, Tunisia. Forty-six samples were collected within a 6-month sampling period. Pharmaceuticals were analyzed using solid-phase extraction followed by ultra-performance liquid chromatography-triple quadrupole mass spectrometry. Thirty-three out of the forty target compounds were detected over a wide concentration of ranges, from nanograms per liter to micrograms per liter, depending on the type of sample. Maximum values were detected for caffeine at 902 mu gL(-1) in hospital wastewater. This compound, as well as salicylic acid, sulfadiazine, and sulfamethizole, were detected in all samples. The average concentration of total pharmaceuticals in hospital wastewater (340 mu gL(-1)) was higher than those detected in influent and effluent wastewater and seawater (275.11 and 0.2 mu gL(-1), respectively). Risk quotients (RQs) were also estimated to provide a preliminary environmental risk assessment and results revealed that sulfadiazine, sulfamethoxazole, and fluoxetine could pose medium/high risk to the tested aquatic organisms for maximum measured concentrations in wastewater (including hospital and WWTP samples). Although the measured environmental concentrations (MECs) detected in seawater samples might not pose a toxic effect to the aquatic organisms (except for salicylic acid, sulfamethoxazole and fluoxetine), further researches are needed due to the continuous release of wastewater in the environment and the limited efficiency of wastewater treatment processes.