Occurrence and Risk Assessment of Pyrethroids and Organophosphorus Pesticides in the Middle Part of Mono River Basin
Résumé
Pyrethroid and organophosphate insecticides are globally recognized as the most extensively used insecticides.
Their potential to accumulate in groundwater raises significant concerns due to the severe threats they pose to both human health
and the environment. This study examined the presence of organophosphorus and pyrethroid pesticides in rivers in the middle of
the Mono river basin and their ecotoxicological risk. To reach these aims, seven organophosphorus pesticides and three
pyrethroids were investigated in thirteen water samples by liquid-liquid extraction and GC-MS/MS analysis. The
ecotoxicological risk was assessed for fish and crustaceans using the risk quotient method, which is the ratio between the
measured environmental concentration and the toxic reference value. The results show that all the targeted pesticides were found,
with maximum concentrations of 0.9647; 0.8947; 0.0978; 0.0908; 0.0602; 0.0578; 0.0483; 0.0468; 0. 0245 and 0.0152 μg.L-1
respectively for Lambda-cyhalothrin; Chlorpyriphos; Deltamethrin; Fenchlorphos; Cypermethrin; Prothiofos; Dichlorvos;
Ethoprophos; Disulfoton and Parathion-Methyl. The detection rate for the first two pesticides was 100%, and 61.54% of water
samples had concentrations above 0.5 μg.L-1, which is the threshold limit for pesticides in drinking water. At the sampling points,
the concentration increases with the distance travelled by the rivers. Risk assessment for aquatic species shows negligible risk for
fish in most rivers analysed. For crustaceans, the risk quotient reveals a moderate and low risk for 46.16% and 53.84% of the
rivers analysed respectively.