ABSTRACT
Antibiotics which were first clinically used in the 1940s in the form of Penicillin, are pharmaceutical products that have the ability to stop infections caused by bacteria by either killing them (bactericidal); or preventing their reproduction (bacteriostatic) and supporting the body’s natural defense to eliminate them. Globally, antibiotics are not only prescribed and used for the treatment of infectious diseases in humans and animals but are also used in livestock and aquaculture for their growth and meat production. Due to misuse and overuse of antibiotics by the clinical settings, private sector, primary healthcare providers and pharmacies, the antibiotics residues and their metabolites have been reported in two water compartments (surface water and groundwater) of the environment. Water quality experts believe that their presence in the environment is correlated with certain resistance from microorganisms which now pose a serious health risk to humans, aquatic organisms and animal husbandry. The qualitative and quantitative determinations of selected antibiotics in surface water and groundwater in Benin metropolis and its environs were investigated in this present research. Water samples were collected from surface (rivers) and groundwater (boreholes) from various households, commercial, medical (hospitals) premises and all the locations were georeferenced. A total of 132 water samples were collected and analyzed. The water samples were first prepared using solid phase extraction (SPE) to enable the extraction, clean up and concentration of the analytes of interest prior to quantification using High Performance Liquid Chromatography (HPLC). Furthermore, selected physicochemical properties of the water samples were also analyzed using recommended standard methods. The results obtained were subjected to statistical analysis. The antibiotics that were detected in the water samples were Amoxicillin, Tetracycline, Ampicillin, and Ciprofloxacin. Erythromycin was however not detected. In terms of frequency at which the antibiotics were found above the limit of detection (LOD), Amoxycillin had the highest detection xiv level of 35.8%, followed by Tetracycline, 22%, Ciprofloxacin, 18.9% and Ampicillin which was 8.3%. High concentrations were recorded in July for Tetracycline, 79µg/L (Ikpoba river, Upper Mission extension), Amoxycillin, 76.2µg/L (Central Hospital), 67.6µg/L (Okhun Community), and 38.3µg/L (Ikpoba river, Upper Mission extension). Ampicillin also recorded a high concentration of 63.7µg/L in Okhuahe River for the month of March. For January, 2022 analysis, Ampicillin recorded a concentration of 50.7µg/L in Orhionmwon river while Ampicillin had a concentration of 39.7µg/L at the Central Hospital for the same month. The results from the physicochemical analysis showed that the pH values for all the locations sampled were all within WHO permissible limits in both the surface water and groundwater. The values for Biochemical Oxygen Demand (BOD5) and Turbidity were slightly above WHO permissible limits in some locations. Furthermore, the highest concentration of heavy metals determined was Fe with a value of 1.44mg/L in Ogba River (surface water). The data generated on the qualitative and quantitative levels of the investigated antibiotics in surface water and groundwater of the studied areas will serve as a baseline for future studies.
