Abstract
The presence of pharmaceutical residues in the environment waters is a serious concern because of the possible ecotoxicological impacts related to long-term exposure of both terrestrial and aquatic ecosystem. Pharmaceuticals end up into the influent wastewater mainly through the domestic sewage system, hospital disposal of wastes, unused and expired drugs and agricultural activities. Most conventional wastewater treatment plants are not capable of efficiently removing pharmaceutical residues from wastewater before discharging effluents into the environment. This is mainly due to the presence of very low concentrations of pharmaceutical residues as well as their diverse chemical structures, modes of action and other properties. Despite the low concentrations of pharmaceutical residues in the environment, their individual toxicities as well as their combinational effects have shown to have detrimental health effects on terrestrial and aquatic organisms. However, there are no maximum discharge guidelines and standards yet, which regulates the discharges and presence of these pollutants in the environmental matrices. Therefore, it is imperative to monitor their concentrations in environmental waters to avoid health effects due to unexpected exposures of humans and other living organisms. In view of the above, the main aim of this study was to develop sample preparation methods for sample clean-up, extraction and preconcentration of pharmaceutical residues, specifically, non-steroidal antiinflammatory drugs and antiretroviral drugs in river water and wastewater matrices. This was achieved by developing four sample pre-treatment techniques which include two magnetic solid phase extraction (MSPE) methods, dispersive microsolid phase extraction (D-μSPE) and supramolecular solvent based dispersive liquid-liquid microextraction (SSDLLME). The quantification of the selected pharmaceuticals was achieved by high performance liquid chromatography equipped with diode array detector (HPLC-DAD)...
Ph.D. (Chemistry)