Ecological Quality of the Water in Lake Ehuikro, the Drinking water Reservoir for the Town of Bongouanou (Côte d'Ivoire)

This study assessed the biological quality of Lake Ehuikro (Bongouanou, Côte d'Ivoire) using microalgae from February to July 2023. We used microalgae as biological indicators of water quality at three selected stations on the lake. The method used is that proposed by Palmer (1969), which consists of translating the level of contamination in water samples. The samples taken enabled 75 taxa belonging to 29 genera to be inventoried, including 39 taxa belonging to the Euglenophyta (52%), 17 to the Chlorophyta (22.66%), 11 to the Cyanoprokaryota (14.66%) and 6 to the Heterokontophyta (8%) and finally 2 to the Dinophyta (2.66%). The pollution-tolerant genera identified were Euglena, Oscillatoria, Scenedesmus, Ankistrodesmus, Phacus, Closterium, Gomphonema and Lepocinclis.The Palmer algal pollution index showed that the lake's three stations have little organic pollution. The total scores at stations 1 and 2 were 8 and 9 respectively, indicating the absence of organic pollution, and 15 at station 3, indicating moderate organic pollution. The results also show that the lake is moderately polluted, with an index of 10. This study is part of the process of making available the results, which will serve as a reference for subsequent investigations into the state of water quality in this water supply source.