Quantitative determination of heavy metal contaminants in edible soft tissue of clams, mussels, and oysters.

Aquatic environments are important sources of healthy and nutritious foods; however, clams, mussels, and oysters (the bivalves most consumed by humans) can pose considerable health risks to consumers if contaminated by heavy metals in polluted areas. These organisms can accumulate dangerously high concentrations of heavy metals (e.g., Cd, Hg, Pb) in their soft tissues that can then be transferred to humans following ingestion. Monitoring contaminants in clams, mussels and oysters and their environments is critically important for global human health and food security, which requires reliable measurement of heavy-metal concentrations in the soft tissues. The aim of our present paper is to provide a review of how heavy metals are quantified in clams, mussels, and oysters. We do this by evaluating sample-preparation methods (i.e., tissue digestion / extraction and analyte preconcentration) and instrumental techniques (i.e., atomic, fluorescence and mass spectrometric methods, chromatography, neutron activation analysis and electrochemical sensors) that have been applied for this purpose to date. Application of these methods, their advantages, limitations, challenges and expected future directions are discussed.