EVALUATION DES TENEURS EN ELEMENTS MINERAUX ET QUALITE DES EAUX SOUTERRAINES DU CONTINENTAL TERMINAL AU SUD-OUEST DU BENIN

Agropastoral activities, the main socio-economic activities along Lake Toho, are not without effects on the quality of soil and water. The objective of this study is to evaluate the degree of transfer of chemical elements and the quality of groundwater from the continental terminal to the southwest of Benin. Thus, along Lake Toho, nineteen large diameter wells and boreholes were sampled and the physicochemical parameters were measured using appropriate analysis methods. The calculation of different empirical indices made it possible to assess the quality and potability of groundwater. The determination of physicochemical parameters showed that the contents of chemical elements contained in the groundwater comply with Beninese standards and those prescribed by the WHO except for temperature, magnesium and chlorides, the values of which were obtained at the wells. Itehoue and Condji Agname are extraordinary. The index values showed that the quality of groundwater is good in 12 localities and of excellent quality (Kpocondji Yosso) in some places. The overall assessment of quality reveals that the water quality is good almost everywhere and excellent in Tohonou Dadahoue in Hahame Agbodougbe average in Itehoue and Bota and very bad in Goudon.