NIVEAU DE CONTAMINATION DUNE EAU DE SURFACE PAR LES PRODUITS PHYTOSANITAIRES: CAS DE LA RETENUE DEAU DU BASSIN VERSANT DE LA LOBO(CENTRE-OUEST DE LA COTE DIVOIRE)

The Lobo is the source of drinking water for SODECI in the department of Daloa. The strong agricultural activity around it can lead to the dissipation of phytosanitary products into the environment. However, the transfer of pesticide residues from agricultural plots to this aquatic environment is little studied or even non-existent. The objective of this work is to determine the state of contamination of the Lobo River by phytosanitary products. The HPLC assays were carried out on water samples taken at the exit of the agricultural plots (upstream) and in the Lobo (downstream). These analyzes revealed the presence of residues of pesticides such as glyphosate, mancozeb 2,4-D and lambda-cyhalothrin at various concentrations. Indeed, at the exit of the agricultural plots (upstream) and in the Lobo (downstream), the average concentrations detected were respectively 0.89µg / L to 0.35 µg / L for glyphosate, 0.81µg / L at 0.38 µg / L for mancozeb, 0.5 µg / L at 0.39 µg / L for 2,4-D, and 0.06 µg / L at 0.02 µg / L for lambda-cyhalothrin. However, these values are higher than the international standard (WHO) which is 0.1µg / L at the exit of the plantations and in the waters of the Lobo except the values ​​of 2,4-D.