Physicochemical Characterization of the Ecological Status of the Waters of the Bays of the Ebrie Lagoon (Abidjan, Cote d'Ivoire)

The intensification of industrial and agricultural activities as well as the rapid increase in the population of the city of Abidjan have a negative impact on the urban waters of the Ebrie lagoon by endangering the aquatic life within its bays. To evaluate the ecological status of these bays, fifteen (15) lagoon water sampling campaigns were conducted from 2014 to 2016 on twelve (12) sites spread over nine (09) bays. The samples were subjected to physicochemical analyzes on the basis of French standards. The results obtained show that the physicochemical characteristics of bays waters are dependent on marine and continental inputs. The bays are subjected to important terrigenous and urban inputs favoring their richness in nutritive salts with rates of exceedance of the limit values recommended by Chapman and Rodier, between 20 and 100 % for nitrite, between 69 and 100 % for ammonium and equal to 100 % for phosphate. It appears that it is the phosphate and the ammonium which strongly degrade the ecological status and which make the waters of the bays unfit to favor an optimal aquatic life for the fauna and the flora.