CONTAMINATION OF THE OUÉMÉ RIVER IN BENIN BY THE TOXIC METALS: CADMIUM, LEAD AND COPPER

Abstract

The assessment of the contamination of Ouémé river by toxic metals (cadmium, lead, copper) is carried out in water, sediments and fish samples. Except for water all the samples underwent the necessary treatments by mineralization before the analysis with atomic absorption spectrophotometer. The results reveal high levels of toxic metals in all the samples. These concentrations exceed the recommended limits for human consumption. The mean contents in mg/kg (fish and sediments) or mg/L (water) are (i) water Cd: 0.47 mg/L; Pb: 1.95 mg/L; Cu: 2.95 mg/L; (ii) sediments Cd: 3.31 mg/kg; Pb: 27.79 mg/kg; Cu: 24.89 mg/kg; (iii) fish Cd: 2.56 mg/kg; Pb: 7.14 mg/kg; Cu: 9.631 mg/kg. These different results show that the water and fish of Bonou ecosystem are unfit for human consumption and could be the origin of different pathologies.