Water quality management in Lake Kivu basin: a case study of Bukavu sub-basin, DR Congo

Water Quality Management in Lake Kivu, and its surroundings, in DR Congo is an issue of very high significance because of great socio-cultural, ecological and economic values. The study was conducted in DR Congo (Lake Kivu Basin/Bukavu sub-basin) to ascertain the major pollution inflow routes and to assess suitability of water for domestic, industrial, recreational and other uses in the lake littoral zones. Samples were collected from rivers (Kahuwa, Wesha and Tshula) and canals (from the brewery and pharmaceutical factory) flowing into Lake Kivu, and in the littoral lake zones. Data analysed for nutrients (in Kg/day) revealed that the rivers and the canals were inevitably polluted by P04 (21.64), NH4 (489.12), N02 (29.85), N03 (456.38), TP (448.57) and TN (7046.10). For the physico-chemical properties, 1125.5 ppm of TDS, 2248.1 mg/L of EC and 1631.6 mg/L of TSS were detected in the stations. At stations RK3, RW3 and RT3, more of the nutrient concentrations were above the standard values. For all parameters analysed, the highest concentration was obtained in River Kahuwa. In Lake Kivu, the concentrations of nutrients decrease from the bank to the littoral zones on water surface level and the concentration of chlorophyll-# is low in that zones. Kahuwa has been identified as the principal source of the pollution load into Lake Kivu in Bukavu sub-basin. The high levels of nutrients in Bukavu sub-basin were attributed to wastewater discharges from industries, market and domestic wastes, runoff from city and anthropogenic activities like agriculture. Reduction of incoming nutrients, monitoring and prevention of future degradation can be the best management strategy to reduce pollution load in Lake Kivu. Appropriate monitoring systems need to be established to check the health of the aquatic environments and the effects of pollution on the biota and human health.