Residues of heavy metals (Hg, Pb, Cd and Cr) in edible snails

A survey was carried out on different species of wild snails collected in Southern Italy and on frozen snails from Northern Italy and imported from different countries to determine the level of heavy metal contamination (Hg, Pb, Cd, and Cr). In wild snail samples, Pb (av. 0.36 mg/kg wet weight) showed the highest mean level, followed by Cd and Cr, whose mean concentrations were similar (av. 0.23 mg/kg wet weight). With regard to the frozen snails from Northern Italy, Cd showed the highest concentration (av. 0.37 mg/kg wet weight), followed by Cr (av. 0.23 mg/kg wet weight), and Pb (av. 0.13 mg/kg wet weight). In the imported snails Cd was the highest (av. 0.39 mg/kg wet weight), followed by Pb (av. 0.19 mg/kg wet weight) and Cr which was at a low level (av. 0.12 mg/kg wet weight). The level of Hg was below the instrumental limit of detection (50 ng/g) in all samples. Because of the ability of snails to accumulate metals in their body, a specific law which fixes maximum metal levels to avoid health risk for the consumers is desirable.