Decadal Changes in the Edible Supply of Seafood and Methylmercury Exposure in the United States

Abstract

Background:Methylmercury (MeHg) exposure is associated with adverse effects on neurodevelopment and cardiovascular health. Previous work indicates most MeHg is from marine fish sold in the commercial market, but does not fully resolve supply regions globally. This information is critical for linking changes in environmental MeHg levels to human exposure in the U.S. population.Objectives:We used available data to estimate the geographic origins of seafood consumed in the United States (major ocean basins, coastal fisheries, aquaculture, freshwater) and how shifts in edible supply affected MeHg exposures between 2000–2002 and 2010–2012.Methods:Source regions for edible seafood and MeHg exposure in the United States were characterized from national and international landing, export and import data from the Food and Agricultural Organization of the United Nations and the U.S. National Marine Fisheries Service.Results:Our analysis suggests 37% of U.S. population-wide MeHg exposure is from mainly domestic coastal systems and 45% from open ocean ecosystems. We estimate that the Pacific Ocean alone supplies more than half of total MeHg exposure. Aquaculture and freshwater fisheries together account for an estimated 18% of total MeHg intake. Shifts in seafood types and supply regions between 2000–2002 and 2010–2012 reflect changes in consumer preferences (e.g., away from canned light meat tuna), global ecosystem shifts (e.g., northern migration of cod stocks), and increasing supply from aquaculture (e.g., shrimp and salmon).Conclusion:Our findings indicate global actions that reduce anthropogenic Hg emissions will be beneficial for U.S. seafood consumers because open ocean ecosystems supply a large fraction of their MeHg exposure. However, our estimates suggest that domestic actions can provide the greatest benefit for coastal seafood consumers. https://doi.org/10.1289/EHP2644

Distribution of mercury‐cycling genes in the Arctic and equatorial Pacific Oceans and their relationship to mercury speciation

“…The concentration and fate of mercury (Hg) in the ocean is controlled by the distribution of four principal species: mercuric ion (Hg[II]), elemental Hg (Hg 0 ), monomethyl-Hg (CH 3 Hg + ; MMHg), and dimethyl-Hg ([CH 3 ] 2 Hg; DMHg). MMHg is a neurotoxin that bioaccumulates in marine food webs and humans are primarily exposed through consumption of coastal and openocean fish, and marine mammals (Debes et al 2016;Madigan et al 2018;Schartup et al 2018;Sunderland et al 2018). Except for the Indian Ocean, which remains untested, MMHg and DMHg have been detected in the water column of every ocean basin (Mason and Fitzgerald 1993;Mason et al 1995;Sunderland et al 2009;Cossa et al 2011Cossa et al , 2018Wang et al 2012Wang et al , 2018Bowman et al 2015Bowman et al , 2016Heimbürger et al 2015;Munson et al 2015;Agather et al In press).…”

Are mercury emissions from satellite electric propulsion an environmental concern?*

“…Marine fish are the predominant vector of methylmercury exposure to human populations in many countries (Sunderland 2007) and thus such deposition patterns could potentially affect future human exposure to mercury. For example, marine fish supply more than 85% of the methylmercury intake to the United States population and the largest contributing source region is the Pacific Ocean (Sunderland et al 2018). Both the tropical Pacific Ocean and Indian Ocean are important supply regions for global tuna fisheries, which account for the dominant fraction of methylmercury exposure for many individuals (Sunderland et al 2018).…”

“…For example, marine fish supply more than 85% of the methylmercury intake to the United States population and the largest contributing source region is the Pacific Ocean (Sunderland et al 2018). Both the tropical Pacific Ocean and Indian Ocean are important supply regions for global tuna fisheries, which account for the dominant fraction of methylmercury exposure for many individuals (Sunderland et al 2018). In figure 3, enhanced mercury deposition regions over the global oceans between 10°and 40°projected to result from satellite emissions correspond to some of the most important harvesting regions for global commercial fisheries (Zeller et al 2016).…”

Influence of the geographical origin on substance concentrations in herring as basis for dietary exposure assessments

“…An effect of geographical origin on concentrations of selected substances could also apply to fillet of fish from different catching areas, as geographical variations in substance concentrations have been observed. Sunderland et al (2018) studied geographical origins of seafood on the market in the United States and the concentration of methyl mercury, and showed that seafood was available from different catching areas and contributed to the methyl mercury exposure with different amounts. Several fish species caught in subareas of the Northeast Atlantic were investigated for methyl mercury and concentrations increased from north to south and by fish length (Azad et al, 2019).…”