Impacts of Agrochemicals on Water Quality Parameters in Aboisso Region (South-East of Cote d’Ivoire)

Aboisso region is experiencing unprecedented agricultural activities. Cultural techniques such as the use of insecticides are harming the quality of water. This study aims to assess the impact of insecticides on the water quality in the Aboisso region. Thirty-one (31) water points (10 surface water and 21 groundwater) were sampled. The determination of physicochemical parameters as well as the multi-residue method used for insecticides analysis in the samples allowed us to achieve our objective. The result of the physicochemical analysis shows that the temperature of groundwater (27.91°C) is higher than surface water temperature (26.77°C). These waters are mostly acidic with a slightly lower pH for groundwater (6.46) compared to surface water (6.54). The conductivity is higher in groundwater (average of 130.46 µS/cm) as opposed to surface water (average of 43.50 µS/cm). After applying the multi-residue method, the results reveal the presence of nine (9) active ingredients. In surface waters, all these molecules, except Lambda-cyhalothrin and Deltamethrin, exceed the WHO guide values (0.1 µg/L). The highest concentrations recorded concern ethyl parathion and profenofos (8.24 µg/L and 8.04 µg/L respectively). In groundwater, it is rather Parathion-methyl, Profenofos, Dimethoate, Chlorpyriphos-ethyl, Lambda-cyhalothrin and Deltamethrin that are often at below WHO standards. However, the present study reveals that all of the water samples analysed were polluted, owing to anthropogenic used of insecticides in the region, and other chemicals with high concentrations of parathion-ethyl: 8.24 µg/L and profenofos: 8.04 µg/L. These waters are therefore unfit for human consumption.