Heavy metal concentrations in Chinese chicken eggs: insights from comparative study of urban and mining areas

The results showed that there were significant differences in the concentrations of heavy metals in eggs from different regions, but the overall concentrations (<i>e.g.</i>, Cd < 0.05 mg/kg, Pb < 0.02 mg/kg) all complied with China's national food safety standards for eggs. Within the same region, free-range eggs contained higher heavy metal levels than commercial eggs. The heavy metal HIs of eggs in mining areas were higher than those in non-mining areas, and the HIs of eggs in heavy metal polluted areas were higher than those in non-polluted areas, which made free-range eggs relatively riskier than commercial eggs. This study indicates that free-range eggs may pose a higher risk of heavy metal exposure. In the vast rural areas of China, the potential risk of heavy metal pollution caused by free-range egg farming deserves greater attention.