More than a quarter of these fish were found to contain mercury at levels exceeding the criterion for the protection of people who consume average amounts of fish, established by the U.S. Environmental Protection Agency. More than two-thirds of the fish exceeded the U.S. EPA level of concern for fish-eating mammals.
Exposure to mercury can damage your brain, kidney and lungs. Symptoms of mercury poisoning typically include sensory impairment, disturbed sensation and a lack of coordination.
This latest study from the U.S. Geological Survey is unique because it focused on mercury in fish from streams across the United States, as opposed to those in lakes, reservoirs and wetlands, which are more commonly studied.
Sadly, though the medium was different, the results were largely the same.
Mercury was detected in every fish sampled from nearly 300 U.S. streams. Among them, 27 percent contained mercury at levels that equaled or exceeded the U.S. EPA’s criterion for the protection of human health, and more than two-thirds exceeded mercury safety levels for fish-eating mammals like mink and otters.
What this does is add further credence to the message I’ve been relaying for nearly a decade: Most of the U.S. fish supply contains harmful levels of mercury.
For comparison, a study a few years back on fish living in lakes and reservoirs found more than half contained excessive levels of mercury -- so much so they were deemed unsafe for children and pregnant women to eat.
Where is All of This Mercury Coming From?
For the most part mercury in the fish and the environment is related to the fact that the majority of electricity is generated from burning coals which releases the mercury into the air and then into the waterways once it rains. There certainly are other industrial sources in some areas but this is the primary source.
Mercury is released from the smokestacks of coal-fired power plants, cement kilns and certain types of mining activities. Once in the air, the toxic mercury rains down into bodies of water. From there it is converted by bacteria into a particularly dangerous form called methylmercury, where it finds its way into fish, accumulating especially in fish that are higher up the food chain.
The larger the fish, the likelier they are to have high levels of this toxin. The National Resources Defense Council points out, for instance, that predatory fish such as large tuna, swordfish, shark and mackerel can have mercury concentrations in their bodies that are 10,000 times higher than those of their surrounding environment!
It’s because of this bioaccumulation that about 40 percent of all U.S. exposure to mercury comes from eating contaminated tuna. And roughly 75 percent of all human exposure to mercury in general comes from eating fish.
Why is Mercury in Fish a Health Risk?
When you eat contaminated fish, the mercury acts as a poison to your brain and nervous system. This is especially dangerous for pregnant women and small children, whose brains are still developing. If infants or fetuses are exposed to mercury, it can cause:
And even in low doses mercury can interfere with a child’s development, leading to shortened attention span and learning disabilities. These risks are incredibly prevalent, as a 2005 report from the Centers for Disease Control and Prevention found that one in 17 women of childbearing age have mercury levels (above 5.8 micrograms per liter) that could harm a developing fetus.
In adults, mercury poisoning can be a serious risk as well, and has been linked to fertility problems, memory and vision loss, and trouble with blood pressure regulation. It can also cause extreme fatigue and neuro-muscular dysfunction.
Mercury is especially damaging to your central nervous system (CNS), and studies show that mercury in the CNS causes psychological, neurological, and immunological problems.
Further, mercury bonds very firmly to structures in your CNS. So unless actively removed, mercury has an extremely long half-life of somewhere between 15 and 30 years in the CNS.
Most Fish is No Longer a Healthy Food Choice
In a perfect world, fish would be a near-perfect food -- high in protein and full of essential nutrients and fats. But our world is not perfect, and, sadly, neither is our fish supply. Therefore, I do not recommend eating any fish -- whether farm-raised or from an ocean, lake, river or stream -- unless you have lab results in your hand that can attest to its purity.
There are still some safe areas out there, such as in certain pristine waters in Alaska, but it will take some searching on your end to seek them out. The ONLY safe fish I have discovered so far is Vital Choice wild red salmon, which remains the only source of fish I’ll eat.
Eating smaller fish, like anchovies and sardines, is also an option, as their small size makes them far less likely to be contaminated.
An important point to remember if you’re not eating fish is that your body still has a requirement for omega-3 fats. Fortunately, you can easily meet your omega-3 needs by taking a high-quality krill oil or fish oil supplement, instead of risking your health by eating contaminated fish.
Which Types of Fish are the Worst Offenders?
If you would still like to indulge in the occasional fish dinner, you should know that some fish are more problematic than others. These are some of the varieties you should definitely avoid -- especially if you are pregnant, expecting to become pregnant or nursing:
Again, it is my strong recommendation to avoid eating most fish other than very small fish or those grown in minimally polluted areas like the Arctic, Antarctic or Alaskan waters.
If you insist on eating typical, store-bought fish, however, and want to know more about the extent of your mercury exposure, I urge you to check out the online mercury calculator at GotMercury.org to get an idea of the risks.
What to Do?
For now it is probably best to avoid fish altogether, however If you choose to eat fish it is best to swallow a mercury chelator with it. There are a number of them on the market that would work such as green clays like Zeolite, chlorella and others.
However the best one is not yet available and was invented last year. It is at least 100 times more potent than the ones I mentioned above and will bind virtually all of the mercury present in your gut and release it harmlessly into your stool.
Our team is currently in negotiations with the research team that developed this and we hope to have it available early next year.