Determination of levels of selected antibiotics in the waters of the Nakivubo Channel, Kampala (Uganda)

Abstract

Antibiotics are one of the most successful forms of chemotherapy developed by modern science, many lives have been saved and diseases or infections that would cause death of humans and pets or lead to poor crop performance in agriculture have been controlled. However widespread application of antibiotics is raising concerns because of increase in the level of resistance by bacteria and environmental pollution by antibiotics residues; the use of antibiotics is on the increase all over the world. Antibiotics are frequently passed out in urine and/ or feces either completely or partially un-metabolized thereby ending up in receiving waters in their raw forms or as degradants which may or may not be active. In this study, the level of occurrence of three selected (most commonly used) antibiotics in the waters of the Nakivubo channel; Kampala (Uganda) was investigated by Spectrophotometric Analysis. Samples of water were taken at selected sites along the Nakivubo channel once every week for ten weeks and analyzed, the selected antibiotics namely: Amoxicillin, Ceftriaxone and Gentamicin were detected only in trace quantities in spite of widespread usage. The average concentrations of antibiotics at the selected sites were: 0.013 µg L -1 for amoxicillin, 0.006 µg L-1 for Ceftriaxone and 0.214 µg L-1 for Gentamicin. The concentrations of amoxicillin and Ceftriaxone were lower than the values acknowledged by WHO (2011) for untreated surface waters while that of Gentamicin was higher than acknowledged values. These findings led to the conclusion that the antibiotics could have been degraded once released into the natural once in the environment. The finding strongly suggests that people using the Nakivubo channel are not exposed to the parent molecules of the three elected antibiotics. The finding however does not imply that all antibiotics are degraded in the environment or that the waters of the Nakivubo channel are not polluted.