Soil, Water and Geomaterials Sciences Laboratory (LSSEG), UFR STRM, University Felix Houphouët-Boigny of Cocody-Abidjan BP 582 Abidjan 22, Côte d’Ivoire
The bay of M’Badon is the receptacle of wastewater of various origins, leaching water from plantations and leachate from the Akouédo landfill. All these inputs are likely to pollute this aquatic environment, which is used by the population for fishing and market gardening. The objective of this study is to determine the quality of the water and surface sediments in the bay. To achieve this, a sampling campaign allowed the collection of a total of sixty-six samples, twelve of leachate, twenty-seven of bay water and twenty-seven of surface sediments. Parameters such as COD, BOD5, NO3-, NO2-, NH4+, SO4-, PO43-, Na+, K+ and Ca2+ were measured by the methods of the French Agency of Standardization and trace metal elements (Zn, Cu, Ni, Cr) were measured by atomic absorption spectrometry. The average values of COD (1306.25 mg O2L-1), BOD5 (575.85 mgO2L-1), NO3- (92.92 mgL-1) and PO43- (128.74 mgL-1) of the Akouédo landfill leachates are well above Ivorian standards. The waters of the bay are turbid, with an average TSS concentration of 65.13 mgL-1. They have a high load of organic and mineral oxidizable matter, with average COD and BOD5 values of 160.70 mgO2L-1 and 64.04 mgO2L-1 respectively. Their mineralization is due to the combination of two processes, one natural and the other anthropogenic. The average NH4+ concentration (0.22 mgL-1) is higher than the French guide value. The sediments of stations B1, B4 and B5 are polluted by Zn and Cu, and the sediments of all stations are polluted by Mo. M'Badon Bay is polluted by anthropogenic activities.
The led study presents the current state of the quality of waters of the tablecloth of Bonoua as well as its situation towards polluting elements of anthropological origin (NO3-, Cl-, NH4 +). This tablecloth is more and more requested to cover the water requirements of the city of Abidjan, while its quality is felt (experienced) by the diverse sources of pollution which multiplied further to the urbanization and to the development of the agro-industrial cultures. To estimate the current subterranean quality of waters of this tablecloth a comparison and a follow-up of its physico-chemical parameters from 2001 till 2015 was realized. It was coupled with a multivariated statistical analysis to know the Analysis in Main Component (ACP) to determine the origin of mineralization, The methodology took into account on one hand the hydrochemical parameters which showed that waters are acid with a pH between ((4,2UpH and 6,88UpH, more important concentrations in nitrates (140mg / L) to Ahoutou