Characterization of Lake Victoria’s water quality at near-shore areas following a rise in the lake’s water level

Abstract

Water pollution around water bodies has continued to be a global problem due to the diverse and increasing pollution sources within the changing world. This study aimed at identifying the potential sources of water pollution, evaluating the spatial variation in the physico-chemical water quality characteristics, evaluating the spatial variation in microbial water quality characteristics at Katosi landing site. A spatial variation was considered and samples were determined for water sampling and were collected at 0 metre, 20 metres and 40 metres. A qualitative approach was adopted to identify the potential sources of water pollution at the landing site. Key informant interview and observation methods were used to collect the qualitative data about the potential sources of water pollution and the findings showed that sources are either point or non-point sources at the Lake. To a greater extent, it was revealed that point source pollutants are the major sources of pollution and these arise from improper and poor waste disposal methods at the landing site of Katosi. Purposive sampling of the water points was done and the water samples were collected and analyzed in the laboratory for physical chemical and microbiological parameters. Parameters analyzed for in the laboratory included electrical conductivity, pH, total nitrogen, total phosphorus, biological oxygen demand, total suspended solids, total coliforms and E. coli. were analyzed using an Analysis of variance (ANOVA) was carried out on Results from the laboratory. The study found there was no significance between Electrical conductivity (P=0.427), pH (P= 0.095) and Total nitrogen (0.078). There was a significance recorded for Total Phosphorus (P=0.009), Biological Oxygen Demand (P=0.02) and Total Suspended Solids (P=0.021) The study revealed that there were no microbiological contaminants in the surface water. The mean difference showed that the shoreline was the most polluted area in the lake where the highest mean difference was recorded at 0 metre at Lake Victoria. Attention was also paid to the absence of microbiological organisms in the water body and could only be influenced by the change in seasons at the Lake. Thus, emphasis was put on other parameters where quite high values of electrical conductivity were recorded and this signified the high rates of pollution at the landing site water.