Heavy metal risks in aquatic foods

Abstract

Aquatic foods provide essential nutrients but can also contain hazardous heavy metals like mercury, cadmium, lead, and arsenic, posing health risks. This study analysed over 138,000 records from the World Health Organization to assess heavy metal levels in aquatic foods, conducting health risk and risk-benefit assessments. Results showed that 97.6 % of aquatic products met safety standards, with mercury at 96.2 % and cadmium at 97.2 % compliance, but species standards varied, and regional compliance differences were observed. Mercury levels are relatively high in fish, while cadmium, lead, and arsenic levels are elevated in molluscs, and cadmium levels are high in cephalopods. Mercury is biomagnified through the food chain, while cadmium, lead, and arsenic exhibit biodilution. Health risk assessment showed that mercury is the primary non-cancer risk, while cadmium, lead, and arsenic are sources of cancer risk. Mercury from aquatic food consumption exceeded the non-cancer risk threshold in 69 countries, and cadmium exceeded cancer risk threshold in 20 countries, while 152 countries remained within acceptable health risk thresholds. Risk-benefit assessment indicated that the health benefits of EPA + DHA intake from aquatic food consumption outweigh the heavy metal-related risks, with net benefit limits higher than safe consumption limits. Current aquatic consumption level is below safe consumption limits, but reducing consumption of high-risk aquatic products can effectively lower health risks. This study provides a global comprehensive evidence base to inform targeted interventions, policies, industry practices, and consumer choices for mitigating risks while promoting sustainable aquatic food consumption as a vital nutritional resource.