Title : Contribution of faecal inputs from the Djibi, Bete, and Me rivers to microbial pollution of the Aghien lagoon in the peri-urban area of Cote d Ivoire
Abstract:
The Djibi, Bété, and Mé rivers, the main tributaries of the Aghien lagoon, are heavily impacted by human activities, receiving domestic wastewater as well as agricultural and livestock effluents containing human and animal feces. The cumulative contributions of these rivers to the Aghien lagoon disrupt the proper functioning of these aquatic resources by modifying their microbial communities, altering the quality of their waters, and compromising the goods and services they provide. This work aims to determine the potential contribution of these rivers to microbial pollution in the waters of the Aghien lagoon. Water samples were collected between 2015 and 2017 and analyzed. The method of calculating the point flow of indicators from the rivers feeding the Aghien lagoon at a given time was adopted. E. coli concentrations increase significantly with flow only in the Bété (p = 0.0132) and Djibi (p = 0.0337) rivers. For intestinal enterococci, these variations are insignificant, increasing in the Bété River (p = 0.136) and decreasing in the Mé River (p = 0.0909). E. coli is more strongly correlated with flow than enterococci. Faecal contamination is higher at low flows and decreases as river flow increases. The Djibi River has the highest bacterial concentrations, followed by the Mé and Bété rivers, with significant bacterial flows in Djibi. The presence of these bacteria in these aquatic environments poses a health risk. An assessment of the effectiveness of sanitation strategies in this anthropized watershed is necessary.
