Assessment of Quality Water in the Western Zone of Ebrié Lagoon, Côte d’Ivoire

Abstract

Waters of the western zone of the Ebrié lagoon are influenced by marine waters and inflows from the Agneby and Bandaman rivers, as well as chemical effluent discharges from agri-food plants and human activities. The objective of this work is to study water quality in the western part of the Ebrié Lagoon. Water samples were collected in sectors IV and V of the Ebrié lagoon from eleven stations during february 2014 to january 2015. Temperature, pH, dissolved oxygen and salinity were measured in situ by a multi-parameter. Transparency was measured by a Secchi disc. Water samples for suspended solids collected are determined using the method described by Aminot and Chaussepied. The result indicate that, mean annual temperature varied between 28.84 ± 0.88°C and 28.91 ± 0.50°C in sectors IV and V respectively. In sector IV, the water is acidic during the rainy season, and alkaline during the dry season in sector V. Mean annual dissolved oxygen values obtained during this campaign were 5.75 ± 1.28 mg/L and 6.19 ± 1.47 mg/L in sectors IV and V respectively. Aquatic life appears to be more normal in sector V than in sector IV. Mean salinity values showed the influence of the Vridi Canal on these two sectors. Mean transparency values were low. average suspended solids values were high, especially in sector IV with 16.22 mg/L. The waters of sector IV are more turbid than those of sector V. Overall, aquatic life is almost normal in both sectors.