Status of Contamination of the Jawfish (Chrysichthys nigrodigitatus, (Lapécède, (1803)) by Organophosphorus Residues in the Hydroelectric Dams of Faé, Kossou and Taabo (Ivory Coast)

Abstract

The present study aims at determining the level of contamination of the jawfish (Chrysichthys nigrodigitatus) by organophosphate residues in the hydroelectric dams of Faé, Kossou and Taabo. Ninety (90) fish were collected from these three dams during eight sampling campaigns. Composite samples were formed, each for two fish. A total of forty-five (45) composite samples were formed. The detection of pesticide residues in the fish samples was determined by gas chromatography-mass spectrometer (GC/MS). The results show that the average total organophosphate residue load at the three dams is 0.184 mg/kg. The Faé hydroelectric scheme had the highest total load of 0.266 mg/kg in fish samples, compared to 0.197 mg/kg for Taabo and 0.089 mg/kg for the Kossou hydroelectric dam. The relatively high average total concentration is observed for parathion-methyl with a value of 0.130 ± 0.023 mg/kg. Chlorfenvinphos, with a total average concentration of 0.046 ± 0.007 mg/kg was the only molecule present in all the fish samples analyzed in the three hydroelectric dams. In addition, most of the molecules detected in the fish samples had concentrations that exceeded the Maximum Residue Limits (MRLs) for pesticides, whose values range from 0.01 to 0.05 mg/kg.