An assessment of the contamination of Achatina achatina by toxic metals in Okpara village (Benin)

Abstract

The assessment of the contamination by toxic metals (Pb, Al, Cd, Cu, Cr, Zn, Mn) has been achieved in samples of the giant snails (Achatina achatina) in the Okpara village (North of Benin). This work has been performed for, lately a survey revealed a strong contamination by toxic metals in sediments, water and fish in the Okpara River which waters this village. Otherwise, it is in this environment watered by the Okpara River,
that snails are picked and consumed. The appropriated samples underwent the necessary treatment by mineralization before the analysis by electrochemical atomic absorption spectrophotometer (Varian A300 with
Zeeman correction), in the Laboratory of Toxicology and Applied Hygiene/UFR of the Pharmaceutical Sciences (Bordeaux-France). The results of the analysis revealed a high bioaccumulation of heavy metals in all the samples and the concentrations exceed the recommended limits for human consumption. Only the level of chromium respects the recommended limits. This study permitted us to confirm as it has already proved by several authors, that the snail is a toxic metal bioaccumulator and can be considered therefore like a bioindicator of pollution, whose consumption will be a risk for health.

Keywords: Environment pollution, snail quality, bioaccumulation, consumption risk.