ASSESSMENT OF PHARMACEUTICAL RESIDUES IN SELECTED SURFACE WATERS IN IJEBU-ODE, NIGERIA USING SOLID PHASE EXTRACTION-HIGH PERFORMANCE LIQUID CHROMATOGRAPHY (SPE-HPLC

Abstract

The presence of pharmaceutical compounds (PCs) in the environment, especially in developed countries, has not only been ascertained, but their adverse impacts have been investigated and reported even at trace levels. However, there is a paucity of information on the occurrence patterns of these compounds in selected African environments like Nigeria. Hence, this study focused on the investigation of seven PCs in some surface waters within Ijebu-Ode, Ogun State, Nigeria, in five major rivers, namely Rivers Ona, Erinwe, Imagbon, Iweni, and Adamegi. These compounds include antibiotics- trimethoprim (TMP), sulfamethoxazole (SMZ), and ciprofloxacin (CIP); analgesics- paracetamol (PCM), diclofenac (DCF), and ibuprofen (IBU) and an antidiabetic- metformin (MET). The analyte PCs were monitored using a solid phase extraction- high-performance liquid chromatographic method (SPE-HPLC) which was developed and validated according to the International Conference on Harmonization guidelines. The highest levels of PCM (2.13 ± 0.28 µg/mL) and CIP (0.50 ± 0.07 µg/mL) were detected in the Erinwe River, while the highest concentrations of SMZ (2.25 ± 0.30 µg/mL) and TMP (0.35 ± 0.05 µg/mL) were detected in River Ona. Generally, the Σ PCs (µg/mL) in the rivers sampled are in the order SMZ (4.09) > PCM (3.01) > CIP (0.78) > DCF (0.56) > TMP (0.46) except for MET and IBU, which were not detectable in any of the rivers. Generally, the results obtained in this study are relatively high; hence, policies must be put in place to commence their removal from the environment.