Evaluation of Metallic Trace Elements Content (Cadmium, Copper, Zinc and Lead) in the Water of Lake Azili in the Municipality of Zangnanado (Centre-Benin)

This study focuses on the assessment of the level of contamination in metallic trace elements (cadmium, copper, zinc and lead) in the waters of lake Azili in the municipality of Zangnanado. The methodology adopted to achieve these results is the method of molecular absorption spectrophotometry. Four sites were sampled at the beginning of November 2020 (period of the long dry season). The results obtained show that the copper content varies between 1.04 mg/l and 1.67 mg/l. The zinc content between 0.2 mg/l to 0.62 mg/l and those of lead recorded are all above 0.05 mg/l. As for their cadmium concentration, they are all above 0.001 mg/l. These results from water analysis of Azili lake show that the sources of this type contamination of the lake are due on the one hand to human activities (dumps of household waste, use of motorized boats) and others other hand to the contributions of the effluents of the lake carrying pesticides. The water quality of Lake Azili is therefore influenced by these various metallic trace elements found there. These results show that the waters of lake Azili are at their beginning of pollution even if it is not yet alarming at the time of our study. Under these conditions, if nothing is done to mitigate it, the pollution will be critical over time.