Variation of water quality in Kakira catchment area, Jinja – Uganda

Kakira Sugar Works Limited (KSWL) owns one of the largest commercial sugarcane plantations and factory in Uganda. KSWL uses fertilizers, pesticides and herbicides to enhance crop yields. This study was carried out to assess the effect of the KSWL sugarcane plantation on the water resources of Lake Victoria. Water quality assessment within and without the sugarcane plantation was carried out for six months over two seasons (wet and dry) and these were tested for physico-chemical parameters. Temperature values at all the sampling sites were <35 °C. pH values at all the sampling sites were within the range of 6.0–8.5 except S4 which was located in the outgrowers’ field (pH = 5.9). Electrical conductivity values on the stream draining through the workers settlement was high (1412.3 μS/cm) compared to the other sampling sites which had values <300 μS/cm. NH4–N and TN values at all the sampling sites were <10 mg/l. Although TP and O–PO4–P values for all the streams were within standards recommended by the National Environment Standard (Standards for Discharge of Effluents onto Water or on Land Regulations) of 1999 for Uganda, the sampling sites including the one located at the lake did not qualify to be categorized as being pristine. Nutrient loads were higher during the wet season than in the dry season. Nutrient loads from the estate were higher than those from the outgrowers’ field. In spite of the fact that nutrient concentrations were within permissible limits, it was concluded that annual nutrient loads of nitrogen and phosphorus could in a long run increase the trophic levels of Lake Victoria.