Evaluation of herbicide contamination in sediments from three lakes in Côte d'Ivoire

Pesticides accumulate in sediments once in the aquatic environment. Thus, these sediments constitute a reservoir for these chemicals and contribute, in the medium to long term, to the pollution of aquatic ecosystems. In order to determine the level of contamination of sediments in different aquatic environments, samples were taken from three dams. The methods used were High Performance Liquid Chromatography (HPLC) to determine herbicides in sediments and gravimetry for the analysis of organic matter. Pesticides were detected mainly in the sediments of Lake Fae, with levels ranging from 0.041 mg/kg to 0.211 mg/kg. As for organic matter, the percentages at the Fae, Kossou, and Taabo dams were 13.32%, 1.44%, and 0.84%, respectively. The levels of pesticides found in the sediments indicate that they are polluted, as these levels exceed the environmental quality standards (EQS) recommended by the European Community. Monitoring systems are therefore now essential in order to preserve these aquatic ecosystems.