Contribution of an organochlorine transport model in the evaluation of groundwater contamination risks in the Abidjan aquifer.

This study is being carried out on the Abidjan groundwater, the exploitation of which has made it possible to equalize the price per cubic meter in Côte d'Ivoire. However, the quality of these waters is increasingly tested by various sources of pollution, particularly the dumping of toxic waste in 2006.

With a view to ensuring an effective water supply for the people of Abidjan, this study aims to develop a decision-making tool to protect the water table against pollution. To achieve this objective, it was necessary to model the transport of dissolved perchloroethylenes through the water table using the Feflow code. Various data were used to develop the conceptual model and the input parameters for the groundwater flow model coupled with the transport.

The calibration of the flow model allowed us to obtain an NRMS = 4.77%, revealing the convergence of the model which was furthermore verified by the modification of the number of meshes. The model was then used for predictive simulations of dissolved perchloroethylene transport at the five selected waste disposal sites. The simulation of the transport of perchloroethylene allowed the horizontal trajectory of the pollutant within the Continental Terminal slick to be understood. The contamination times vary from 9 to 47 years. This study undoubtedly favours the sustainable management of groundwater resources in the District of Abidjan by resolving accidental or point source pollution problems.

Key words: Pollution, Abidjan groundwater, modelling, transport, perchloroethylene, Feflow, Abidjan District.