An overview of the present status of Water Quality of Lake Victoria, Kenya: A limnological perspective

Abstract

Sampling for nutrients, Chrolophyll-a and total suspended solids was done in 9 in-lake stations in the Kenyan part of Lake Victoria between December 2000 and October 2001. In-situ measurements of temperature, dissolved oxygen and water transparency were also carried out. PO4-P was found to range from 0.007mg/l to 0.057 mg/l and was higher in the pelagic stations than in littoral stations. NO3-N concentrations of 0.005-0.037 mg/l were recorded and were found to be relatively higher in the littoral stations than in the pelagic stations. TN:TP ration of the lake was found to be 6.78 indicating a possibility of heterocystous blue-green algae dominating. The ratio of 8.6 in the littoral stations showed a potential for higher photosynthetic rates in this part of the lake than in the pelagic zones. SRSi levels in the pelagic zones were found to have reduced significantly compared to those reported by Talling (1965), whereas those in the littoral zone was within the reported range. Water temperature was found to have increased and transparency values decreased compared to those measured by Worthington (1930) for both the open waters and within the gulf. Anoxic conditions (DO <1mg/l) were measured in depths of up to 30m.