A multicriteria analysis to assess the pollution in the southern coastal area of Sfax

The coastal marine area of Sfax (Tunisia) is a well-known zone by its high productivity and fisheries. However, it is threatened by a variety of pollution sources contributing to a degradation of the water quality. In this paper, a study involving 20 stations and 23 physico-chemical and biogeochemical parameters is proposed. Due to the multicriteria nature of the problem, De Smet et al.'s method is used to assess the pollution level in this coastal area. The application of this approach leads to three groups of stations with different pollution levels. The results show that PO3–4, BOD5, COD, MN2+, Cl– and SO2–4 are the main factors of the pollution. In addition, they indicate that the SIAPE discharges and the phosphogypsum wastes are the main source of PO3–4, Cl– and SO2–4 which explain the high COD. Thus, an urgent action leading to control the loading of these industrial wastes into the sea is a necessity in order to reduce the pollution and to avoid its propagation.