{"id":1385,"date":"2012-06-01T11:44:00","date_gmt":"2012-06-01T15:44:00","guid":{"rendered":"http:\/\/ncseagrant.ncsu.edu\/coastwatch\/?page_id=1385"},"modified":"2024-08-29T09:22:49","modified_gmt":"2024-08-29T13:22:49","slug":"hunting-for-quicksilver-testing-local-seafood-for-mercury","status":"publish","type":"post","link":"https:\/\/ncseagrant.ncsu.edu\/coastwatch\/hunting-for-quicksilver-testing-local-seafood-for-mercury\/","title":{"rendered":"Hunting for Quicksilver: Testing Local Seafood for Mercury"},"content":{"rendered":"\n\n\n\n\n
Selecting seafood can be mind boggling. Low in saturated fats and packed with healthful omega-3s, fish are definitely good for you. Except when they’re not. So what’s in your seafood that you might want to avoid? Some North Carolina scientists sought to answer a part of that question.<\/p>\n\n\n\n
Researchers from North Carolina State University and Duke University set out to determine mercury levels in fish commonly caught and consumed in North Carolina, recognizing that accurate local consumer information about seafood was lacking.<\/p>\n\n\n\n
What they found about the fish and shellfish they sampled is good news to the ears \u2014 and stomachs \u2014 of local seafood lovers, fishermen and retailers alike.<\/p>\n\n\n\n
In general, the majority of seafood the researchers tested had low levels of mercury, lower than the U.S. Environmental Protection Agency’s consumption guidelines. In instances where researchers found samples with concentrations over EPA’s recommended levels, they were from fish that were known to be high in mercury.<\/p>\n\n\n\n
NC State scientists studied mercury levels in commercial and recreational offshore fish, while Duke researchers tested inshore species for mercury and PCBs. Both projects were funded by the N.C. Fishery Resource Grant Program, which is administered by North Carolina Sea Grant.<\/p>\n\n\n\n
“This research focuses on providing information about locally caught species, which is as accurate as you can get to make your own decisions about North Carolina seafood. Further, the research focuses on mercury and PCBs, both contaminants often mentioned when discussing seafood choices,” says Marc Turano, who oversees FRG projects for Sea Grant.<\/p>\n\n\n\n
But the studies also were driven by another factor: to determine if regional and national seafood guides were serving local consumers.<\/p>\n\n\n\n
“There is a lot of confusion for those who attempt to purchase seafood,” Turano adds. “Most of this confusion surrounds how various groups determine their recommendations.”<\/p>\n\n\n\n
For example, Monterey Bay Aquarium, Food and Water Watch, and Blue Ocean have seafood watch lists that advise consumers what seafood to eat based on their definition of sustainability and their position on catch methods, with indicators for species considered high in mercury. However, these lists are based on nationwide or regional information. The researchers wanted to provide specific data on North Carolina seafood.<\/p>\n\n\n\n
“We’re advocating for, whenever possible, providing consumers with local information for seafood consumption,” explains Derek Aday, a faculty member in NC State’s biology department. However, the final decision about what to eat is not his to make.<\/p>\n\n\n\n
“Our job isn’t to tell people how to act,” he says about his role as a scientist. Instead, it’s “to give as much information as we can give so that, within their own sort of constraints, their own feelings about risk tolerance, they can make informed decisions.”<\/p>\n\n\n\n
The level of mercury that consumers will accept varies from person to person. “The bottom line is that everybody has a different level of risk tolerance,” Aday observes.<\/p>\n\n\n\n
Mercury occurs naturally in the Earth’s crust but the majority in the environment is from human actions, such as coal-fired power plants, mining activities and industrial discharge. It is a neurotoxin. High doses can damage the brains and nervous systems of fetuses, babies and young children.<\/p>\n\n\n\n
In aquatic systems, mercury can be converted into methylmercury, a form that can be absorbed and stored, or bioaccumulated, by fish and other sea creatures. There are several drivers of mercury accumulation in fish, mainly size of the animal, its trophic level or location in the food web, and pH of the water where it is found. The main source of human exposure to mercury is through seafood.<\/p>\n\n\n\n
There are several reasons why mercury content differs in fish. You are what you eat applies to fish too. “If you’re at the top of the food chain and you’re eating a lot of other fish, then your body’s burden is representative of the food that you’ve been consuming over the course of your life,” Aday explains. A fish that is high in the food web likely eats other fish and invertebrates, further concentrating mercury in its body.<\/p>\n\n\n\n