Mercury Contamination in Fish From the Gulf of Mexico

Abstract

Mercury (Hg) is an environmental toxin that contaminates fisheries throughout the world. Mercury is deposited from the atmosphere as inorganic Hg. In aquatic ecosystems, inorganic Hg is converted by bacteria to toxic methyl mercury (MeHg). MeHg readily bioaccumulates in aquatic food chains. Most of the Hg in fish muscle tissue is MeHg. Consumption of MeHg contaminated fish is the primary pathway of MeHg into humans. Methyl mercury can have negative impacts on human health and is especially hazardous to developing fetuses. Fish advisories are used to inform consumers about fish with high levels of MeHg. All of the Gulf of Mexico is under an Hg advisory. Because many commercially available fish are caught from this region, it is important to understand the status of MeHg contamination of different fish species in the Gulf of Mexico. The objective of my study was to determine mercury concentration in 44 species of fish from the Gulf of Mexico collected off the coast of Louisiana. Mercury concentrations in muscle tissue of individual fish were determined using a Direct Mercury Analyzer. Mercury concentrations varied between species. Several species had MeHg concentrations over 300 ng/g, the threshold concentration of MeHg in fish recommended by the US EPA for the issuance of fish consumption advisories.