Heavy metals, such as mercury, cadmium and lead, are a threat to public health, even at low concentrations, since long-term chronic exposure may result in the accumulation of toxic levels. Low to intermediate levels of exposure are associated with chronic toxicity, so detection in food is relevant from a toxicological point of view. Cadmium and lead are scarce in igneous rocks and their presence in the marine environment is usually related to anthropogenic inputs from the atmosphere and rivers; they are also considered good indicators of coastal environment pollution (Prego et al. 1999). Environmental lead contamination arises from various sources, including manufacturing processes, paints and pigments, atmospheric emissions from motor vehicles,
