A new study from the U.S. Geological Survey (USGS) found unhealthy levels of mercury in fish across the country. According to the U.S. Department of the Interior, scientists detected mercury contamination in every fish sampled in all 291 streams sampled.
Over a quarter of the fish tested were found to have mercury levels over the levels considered healthy for people who consume an average amount of fish. Over two thirds of the fish tested exceeded the U.S. Environmental Protection Agency’s (EPA) level of concern for fish-eating mammals.
“This study shows just how widespread mercury pollution has become in our air, watersheds, and many of our fish in freshwater streams,” said Secretary of the Interior Ken Salazar. “This science sends a clear message that our country must continue to confront pollution, restore our nation’s waterways, and protect the public from potential health dangers.”
There has been concern about the levels of mercury in fish for some time. According to the EPA, almost all fish and shellfish contain traces of mercury, but the levels do not pose a risk to most people. The Food and Drug Administration (FDA) and EPA advise women who are pregnant or may become pregnant and young children avoid certain types of fish that are known to contain high levels of mercury.
“This is study is very important because it is the most comprehensive study to date of mercury in streams and rivers, we sampled water, stream sediment and fish in nearly 300 streams across the country. And we found mercury in all of the fish that we sampled,” said Lia Chasar, the lead ecologist on the USGS study.
The study points to a confluence of causes that have led to pervasive mercury contamination.
“Most of the mercury in our waters comes from atmospheric deposition, that’s mercury that gets emitted from coal fired power plants and waste incineration,” and then it can get rained out from the atmosphere. Chasar also added that the study found evergreen forests and wetlands were particularly sensitive to mercury because those ecosystems assist in converting mercury to methylmercury, the neurotoxin form of mercury.
To find out more about the safety of certain fish in your area, see the EPA’s National Listing of Fish Advisories.
Photo courtesy of CDC/ Bette Jensen Creation