Akilinon Gansso Valentin^1,, Kombo Mananga Olivier Simon², Yaya Coulibaly³, Yapo Ossey Bernard^{2, 4}

The increasing enrichment of the estuarine waters of the Ebrié Lagoon with faecal bacteria represents a potential risk of faecal contamination of this ecosystem. In order to combat this phenomenon, the aim of this study is to determine the extent to which these waters are enriched with faecal bacteria. Fifteen lagoon water sampling campaigns were carried out from 2014 to 2016 at eleven (11) stations. The samples were subjected to physico-chemical and bacteriological analyses based on French standards. The results show that bacterial counts give values between 9000 and 2330000 CFU/100mL for faecal coliforms, between 390 and 320000 CFU/100mL for faecal streptococci and in the range 233 and 4600 CFU/100mL for Clostridium perfringens. Water contamination by faecal bacteria is therefore high, and is mainly of human origin. The level of contamination is very high in the bays of Marcory, Cocody and Yopougon because of the strong anthropic pressures exerted there and their state of confinement. However, the level is low in bays less influenced by human activity, such as Anna and M'Badon. According to WHO/UNEP standards, the waters analysed are unhealthy and unsuitable for all seaside activities.

Ebrié Lagoon, Faecal bacteria, Faecal contamination, Water quality