Determination of naproxen, diclofenac and ibuprofen in Umgeni estuary and seawater: A case of northern Durban in KwaZulu-Natal Province of South Africa

In recent years, the occurrence of pharmaceuticals including non-steroidal anti-inflammatory drugs in Umgeni River water system in South Africa has been a concern to the scientific community. In this study; naproxen, diclofenac and ibuprofen were isolated from various water samples (river, estuarine and sea water) using the solid-phase extraction technique based on Oasis hydrophilic-lipophilic balance cartridges. The extracted compounds were identified and quantified using high performance liquid chromatography-photo diode array detector. Validation of the analytical method was performed by spiking seawater with a mixture of all the three pharmaceuticals at 0.025 mu g/L. Percentage recoveries for naproxen, diclofenac and ibuprofen were 82.3, 65.5 and 79.5%, respectively. The analytical method quantitation limits for naproxen, diclofenac and ibuprofen were 0.025, 0.036 and 0.035 mu g/L, respectively. Diclofenac was not detected in any of the analysed river, estuarine and seawater samples. Naproxen was quantified in all water samples and reached a maximum concentration of 0.36 mu g/L in river water. In seawater, naproxen and ibuprofen were detected up to 0.16 and 0.17 mu g/L respectively. The occurrence of these pharmaceuticals in water resources is a cause of concern due to potential impacts on the wellbeing of aquatic organisms and humans. (C) 2019 Elsevier B.V. All rights reserved.