Mercury concentrations in domestic and imported canned bivalves and cephalopods sold in northwestern Mexico

Mercury (Hg) is mainly incorporated into humans through the consumption of contaminated foods. Mercury was measured and the methyl-Hg (MeHg) concentration was estimated in canned mollusks sold in northwestern Mexico to assess the health risk to consumers. Five mollusk types were considered: oysters, clams, octopuses, mussels, and squids. The Hg concentration of mussels was significantly (P < 0.05) lower than those of the other bivalves (oysters and clams) and cephalopods (squids and octopuses). The average Hg concentration in bivalves (0.013 mg·kg–1) was significantly (P < 0.05) lower than that of cephalopods (0.018 mg·kg–1). The estimated MeHg concentrations were also lower in bivalves than in cephalopods. Based on our results, no health risk is associated with the consumption of canned mollusks that are sold in northwestern Mexico. The Hg and MeHg concentrations followed the order of octopuses > squids = clams > oysters > mussels. The Hg and MeHg concentrations in the mollusks evaluated in this study were below the maximum permissible limits for human consumption in Mexico.