Mercury Levels in Fish

This recent bit of fishy news kind of freaks me out:

According to a recent study by the US Geological Survey, every single fish sampled from 291 streams across the United States between 1998-2005 was contaminated with mercury.


A quarter of the sampled fish contained levels of mercury higher than those deemed safe for human consumption and more than two thirds contained levels exceeding the Environmental Protection Agency’s level of concern for the protection of fish-eating mammals.

Most of the mercury comes from coal power plant emissions, where the mercury in the atmosphere gets precipitated down, then converted to methyl mercury, the toxic stuff polluting our waterways.

Now I know I’m a veggie so I don’t need to worry about my own safety, but there’s the planet and the rest of its fish-eating species to worry about – people included. Barbara Scudder, a scientist with the USGS, advises that people should eat more fish species lower down the food chain, such as perch, bluegill or crappie.

Elsewhere, Ward Eldred asks a few interesting questions that I wouldn’t mind knowing the answers to:

The question I want answered is how much mercury was in the streams and fish 30 years ago? 50 years ago? Has it increased? The article says it comes from coal-fired power plants. Oh, and it comes from areas mined for gold and mercury. Does it perhaps just naturally leach from the earth? And has it been doing it for millions of years?

5 thoughts on “Mercury Levels in Fish

  1. jw

    I’d like to emphasize this point from the DOI press release –

    “Since USGS studies targeted specific sites and fish species, the findings may not be representative of mercury levels in all types of freshwater environments across the United States.”

    This was not a random sampling of fish from all over the US, they were targeting specific areas. I’m assuming areas where there was concern about potential mercury pollution. I would encourage people to check for fish advisories before consuming any fish caught in their local streams or lakes.

    To answer the other questions, here is some info I pulled from the Wisconsin Mercury Sourcebook

    “It has been estimated that 70-80% of mercury emissions are related to human activities, although this is a difficult estimate to calculate.”

    “Dated sediment cores from the Great Lakes, which show that mercury levels were extremely low in 1900, surged
    greatly thereafter, peaking between 1950 and 1970, and have fallen back a bit since.”

    I would guess that mercury in lake sediment cores would correlate to mercury levels in fish and the decrease in mercury levels in recent decades is probably due to environmental regulation and pollution controls on power plants, but I don’t know for sure.

  2. maris

    Yikes this is scary. Its so important to think about what we’re putting into our bodies but so many of us don’t even realize things like mercury, etc.

  3. MaryMoh

    Very good piece of info. Not only is mercury found in fish but in our mouth from all the amalgam fillings. This earth is obviously not safe in all ways. But eating a healthy diet helps, so is staying informed and making right choices.


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