Bioconcentration of heavy metals in the snails archachatina marginata and limicolaria spp of the Ouémé Valley in Benin

Abstract

Snails meat of the Achatinidae family is highly appreciated by many African populations and Beninese in particular. But these snails have the ability to absorb and concentrate on their body some toxic chemicals such as heavy metals. This study aims to evaluate the contamination level of heavy metals (Cd and Pb) in snails consumed by the Ouémé Valley populations. Analytical method used to determinate heavy metals levels in samples species Archachatina marginata and Limicolaria sppsampled was Reverse Voltammetry. Results indicated that for Archachatina marginata, the mean cadmium concentrations recorded ranged from 0 to 0.032 mg/kg whereas those from lead ranged from 0.047 to 0.342 mg/ kg. As for Limicolaria spp, the average cadmium concentrations recorded range from 0 to 0.187 mg/kg, while those from lead range from 0.012 to 0.878 mg/kg. Heavy metals concentrations are all below the standards accepted by European Union in all communities with the exception of one where lead concentrations exceed the norm. Limicolaria spp concentrated lead and cadmium more than Archachatina marginata, and heavy metal concentrations are not directly related to the morphological characteristics of snails (length,diameter and weight). To avoid health issues due to lead, it would be important for the populations of the Ouémé Valley to vary their diet and especially to eat less frequently snails.