The occurrence of selected antibiotics in fish and benthic invertebrates (oligochaetes) from lake victoria, uganda

Abstract

The environmental occurrence of antibiotics has been a source of growing concern. The vast increase in production and usage of antibiotics is due to urbanization in areas of Lake Victoria basin. This has contributed to their prevalence in surface water and subsequent release of these compounds is unavoidable to the environment. This problem has been exacerbated by existing water treatment facilities that are not designed to eliminate these compounds from waste streams. The compounds were extracted from Nile tilapia (Oreochromis niloticus) fish fillet and oligochaetes using solid phase extraction (SPE) and analyzed using Liquid Chromatography-Tandem Mass Spectro photometer (LC-MS/MS). A total of ten antibiotics were detected, with chloramphenicol and tetracycline recording the highest values in the detected analytes. The total (Σ) concentrations of selected antibiotics in fish samples ranged from 0.605 ng/g to 32.861 ng/g while in worms they varied from 0.909 ng/g to 73.072 ng/g. The study has shown that sulfamethoxazole, levofloxacin and chloramphenicol were the most frequently detected antibiotics. This may be due to aquaculture activities, ambient wastewater discharge and runoff from farming being singled out as the major sources of antibiotics into the lake. The concentrations of antibiotics in the analyzed samples were below the defined threshold level of resistance which makes consumption of the fish from the bay pose no significant risk of exposure to the studied antibiotics. Therefore, there is a need to sensitize the regional population about the necessity to protect the lake’s ecosystem of emerging contaminants from agricultural and urban centers. Water and Waste Water Treatment Plants need to be equipped with advanced technologies to minimize pharmaceutical residue release.