Physico-Chemical and Biological Characteristics of the Nklobisson Artificial Lake in Yaounde, Cameroon

The deterioration of water quality in lakes constitutes an environmental problem faced by humanity. The Nkolbisson artificial lake which is located downstream of the Abiergue and Mintotomo streams in Yaounde is under the influence of various forms of pollution, mostly resulting from human activities. There is proliferation of algae on the lake surface that consumes the available oxygen in the lake. The main objective of the current study is to evaluate the different forms of pollutants in the lake, in order to propose efficient solutions for a suitable management strategy, basing on the physico-chemical and biological analysis. The lake retains an average of 2535.49 tons/year of suspended solids in the rainy season and 1438.05 tons/year in the dry season. The range of dissolved oxygen (5.2 - 3.8 mg/l); pH (7.8 - 6.8); temperature (23.9°C - 23.1°C); electrical conductivity (266.1 - 87.3 μS/cm); turbidity (22.3 - 10 UNT); suspended solid (240 - 40 mg/l); BOD (55 - 8 mg/l); COD (76 - 87.3 mg/l). Biologically, faecal coliforms fluctuates between (42 × 102 - 425 × 103 FCU/100 ml), faecal streptococci (8 × 103 - 158 × 103 FCU/100 ml) and total Coliform (15 × 103 - 78 × 106 FCU/100 ml) evidence that, the studied lake is highly polluted. Consequently the lake retains an average of 2888.7 tons/year of suspended matter.