Occurrence and removal of pharmaceutical residues in water: A case study of the Lake Victoria basin-Kenya

Abstract

In the recent years, global concerns have increased on the environmental occurrence of Pharmaceutically Active Compounds (PhACs) due to their pronounced ecotoxicological risk. Several studies have shown their presence in different environmental matrices including water, sediments and biota. Whereas the occurrence of these compounds has been widely studied in the western world, few studies have been done in Africa. Additionally, the fate of PhACs during wastewater treatment by stabilization ponds and trickling filters commonly used in low- income countries, is not well known. To narrow this knowledge gap, this study investigated the occurrence of PhACs in water, snail tissues and sediments in 48 surface water systems and their removal in four selected wastewater treatment plants (WWTPs) within the Lake Victoria Basin, Kenya. Water samples from surface water were directly injected into the Liquid Chromatography-High Resolution Mass Spectrometry (LC-HRMS) for chemical analysis while wastewater samples were first processed using solid-phase extraction before analysis. Extraction of chemicals in snail tissues was done using QuEChERS (quick, easy, cheap, effective, rugged and safe) method while pressurized liquid extraction was applied to sediment samples prior to chemical analysis.