Occurrence and Concentration of Pesticides in the Water and Tissues of Two Species of Fish from Lake Guessabo Surrounded by Agricultural Land (West, C�te d'Ivoire): Potential Risks for Humans and for Ecological Receptors

Guessabo lake is very importance for its ability to provide abundant fishery resources and to provide natural habitat for many aquatic species. However, its ecological balance is threatened by various pollutants generated by agricultural activities. The aim of this study is to assess the ecological risks and the presence of pesticides in surface water and in freshwater fish tissue by the QuEChERS method. Thus, the pesticide concentrations were compared to regulatory and toxicological values. The pesticides found mainly in terms of concentration and presence in water was aldicarb (10.40 ?g/L), simazine (9.36 ?g/L), desisopropylatrazine (1.37 ?g/L), monolinuron (0.87?g/L) and parathion - methyl (0.75?g/L, chlorfenvinphos (0.84 ?g/L), methabenzthiazuron (3.44 ?g/L), metazachlor (1.55 ?g/L), isoproturon (2.11 ?g/L) and cyanazine (0.42 ?g /L). The levels of these pesticides detected in the water are higher than the safety levels recommended for drinking water, which is a concern for the health of the local population since they use this resource for consumption in many camps. Pesticide residues were also found in muscle tissue from 14 of 22 fish (63.6%) analyzed. Aldicarb was most frequently quantified in the muscles of Chrysichthys nigrodigitatus and Oreochromis niloticus (55.5% and 63.63% of samples tested, respectively). Concentrations of pesticides in water compared to toxicological benchmarks and the high presence of pesticides in fish indicate likely harmful effects on populations of fish and other biota due to the presence of insecticides. In view of these findings, additional weight - of - evidence research is needed to prioritize the management of agricultural products and implement restoration measures to prevent several fish species from becoming endemic and threatened.