No abstract

Gulf of Mexico (Gulf) fisheries account for 41% of the U.S. marine recreational fish catch and 16% of the nation's marine commercial fish landings. Mercury (Hg) concentrations are elevated in some fish species in the Gulf, including king mackerel, sharks, and tilefish. All five Gulf states have fish consumption advisories based on Hg. Per-capita fish consumption in the Gulf region is elevated compared to the U.S. national average, and recreational fishers in the region have a potential for greater MeHg exposure due to higher levels of fish consumption. Atmospheric wet Hg deposition is estimated to be higher in the Gulf region compared to most other areas in the U.S., but the largest source of Hg to the Gulf as a whole is the Atlantic Ocean (>90%) via large flows associated with the Loop Current. Redistribution of atmospheric, Atlantic and terrestrial Hg inputs to the Gulf occurs via large scale water circulation patterns, and further work is needed to refine estimates of the relative importance of these Hg sources in terms of contributing to fish Hg levels in different regions of the Gulf. Measurements are needed to better quantify external loads, in-situ concentrations, and fluxes of total Hg and methylmercury in the water column, sediments, and food web.

Dramatic declines in mercury levels have been reported in Everglades biota in recent years. Yet, methylmercury (MeHg) hot spots remain. This paper summarizes a risk assessment of MeHg exposure to three piscivorous wildlife species (bald eagle, Haliaeetus leucocephalus; wood stork, Mycteria americana; and great egret, Ardea albus) foraging at a MeHg hot spot in northern Everglades National Park (ENP). Available data consisted of literature-derived life history parameters and tissue concentrations measured in 60 largemouth bass (Micropterus salmoides), 60 sunfish (Lepomis spp.), and three composite samples of mosquitofish (Gambusia holbrooki) collected from 2003 to 2005. To assess risk, daily MeHg intake was estimated using Monte Carlo methods and compared to literature-derived effects thresholds. The results indicated the likelihood was very high, ranging from 98-100% probability, that these birds would experience exposures above the acceptable dose when foraging in northern ENP. Moreover, the likelihood that these birds would experience exposures above the lowest-observed-adverse-effect level (LOAEL) ranged from a 14% probability for the wood stork to 56% probability for the eagle. Data from this study, along with the results from several other surveys suggest that biota in ENP currently contain the highest MeHg levels in South Florida and that these levels are similar to or greater than other known MeHg hot spots in the United States. Given these findings, this paper also outlines a strategic plan to obtain additional measured and modeled information to support risk-based management decisions in ENP.

No abstract

While there is a significant amount of data showing health benefits of increased fish consumption, there are conflicting reports about the cardiovascular risks of mercury in seafood. A recent long-term study attempted to resolve this controversy, providing an opportunity to balance recommendations from the US Environmental Protection Agency for mercury with those from the American Heart Association for fish consumption.