Risk evaluation of pharmaceutical residues in waste water from selected treatment plants in Gwangju, South Korea

N.O. Offiong, E.S. Lema Lema, S. Kang, E. Inam Inam, S.Y. Kang, K.W. Kim


The occurrence and removal of three anti-inflammatory drugs (ibuprofen, diclofenac and ketoprofen), an anti-epileptic drug (carbamazepine), an antipyretic drug (acetaminophen), an antibiotic (sulfamethoxazole) and a lipid regulator (gemfibrozil) in influent and effluent samples from three wastewater treatment plants (WWTPs) excluding hospitals and industrialized locations in Gwangju were evaluated. Analytical determination was carried out by high performance liquid chromatography interfaced with a mass spectrometer (LC-MS). All pharmaceutically active compounds (PhACs), except diclofenac, were detected in wastewater influents and effluents. Diclofenac was detected in only one influent sample at a concentration of 7.8 ng/L. Other target compounds were detected at various ranges of concentrations: acetaminophen (7.4-12.9 ng/L), carbamazepine (0.4-35.0 ng/L), sulfamethoxazole (0.1-4.2 ng/L), ketoprofen (55.4-888.4 ng/L), gemfibrozil (16.16-17.1 ng/L), and ibuprofen (22.6-8330.9 ng/L). Removal rates of the pharmaceuticals ranged between 2.9 % to 100 %. Risk quotient, which was expressed as a ratio of the measured environmental concentration (MEC) and predicted no-effect concentrations (PNEC) were evaluated for green algae, fish and invertebrates. Majority of the pharmaceuticals, except acetaminophen, were found in effluent samples at sufficiently high concentrations that would pose adverse risk to aquatic organisms. 

Keywords: emerging contaminants, pharmaceuticals, wastewater, risk assessment, WWTPs

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