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Climate change and overfishing are boosting toxic mercury levels in fish

We live in an era — the Anthropocene — where humans and societies are reshaping and changing ecosystems. Pollution, human-made climate change and overfishing have all altered marine life and ocean food webs. Increasing ocean temperatures are amplifying the accumulation of neurotoxic contaminants such as organic mercury (methylmercury) in some marine life. This especially affects top predators including marine mammals such as fish-eating killer whales that strongly rely on large fish as seafood for energy.

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  5 Reasons Why Concerns about Mercury in Fish Are Misguided

As long as you are eating fish that contains more selenium than mercury, the amount of selenium in the body will always be in plentiful excess of mercury. That means that these essential selenoenzymes are never inhibited to a meaningful degree. Fortunately, the vast majority of fish most people consume have more selenium than mercury. The exceptions are pilot whale, shark, tilefish, king mackerel and swordfish.

 Mercury in Seafood | Should We Really Be Concerned?

With its low melting point, high density, and excellent conductivity, mercury has several industrial and scientific applications. But the unsafe use of this metal can result in severe health and environmental implications, especially through bioaccumulation in seafood. Mercury that enters water bodies, particularly oceans, turns into a compound called methylmercury because of biogeochemical conditions in marine water and the action of microorganisms living in water and soil. Seafood methylmercury in a changing ocean. In Predicting Future Oceans. Elsevier. Unlike mercury, methylmercury can bioaccumulate because the organs, tissues, and muscles of living organisms can absorb it.

Articles of Interest

Can Eating Too Much Tuna Give You Mercury Poisoning?

I’m poor, and lazy, but also occasionally health conscious, so I eat quite a bit of canned tuna. Not what you’d call an extraordinary amount—maybe two to three cans a week—but enough for it to qualify as a dietary staple. Enough, at the very least, for me to stop and wonder from time to time: is this maybe too much? Can you overdose on tuna? Or, more specifically: what would it take for a person to overdose on tuna?

Canned Tuna Is Too High In Mercury for Pregnant Women: Health Group

But scientists at the Environmental Working Group (EWG) show that even if women follow the government’s advice on which types of fish to eat while they’re pregnant, they may be exposing themselves and their unborn babies to unsafe levels of mercury — and not gaining the benefits of the omega-3 fats that they believe they’re getting from the fish. The reason, the EWG charges, is that the list of high-mercury fish is incomplete or inaccurate.

Debunking the Mercury Myth

Since the original FDA consumption guidelines were developed in 2000, Americans have been concerned about mercury in seafood. These early guidelines were issued out of caution when research wasn’t available. However, studies conducted since then have shown fears of mercury toxicity from eating seafood are largely unfounded.

Eating Seafood: Health Boon or Health Threat?

So which fish are safe to eat? And which fish provide the greatest health benefits?

Fish can bounce back quickly from mercury pollution

Fish can bounce back quickly from mercury pollution.

Fish Can Recover Surprisingly Quickly From Mercury Pollution

If the chemical stops leaking into freshwater ecosystems, its concentration in some fish species can drop by more than 75 percent.

Fish FAQ: What You Need to Know About Mercury

In environments without oxygen, mercury combines with carbon to become methylmercury, a highly toxic compound. Bottom-dwelling fish consume methylmercury particles on the ocean floor and are then eaten by larger fish. Large fish such as sharks, swordfish and king mackerel contain the largest amounts of methylmercury because they're higher up in the food chain.

Fish Mercury May Not Harm Older Adults

Aging baby boomers hooked on fish may have cause for cheer. Results from a new study in the Journal of the American Medical Association suggest that higher levels of mercury in the blood from fish consumption do not adversely affect an older person's behavior or learning abilities.

Hold the Mercury: How to Avoid Mercury When Buying Fish

Despite evidence linking mercury exposure from seafood consumption to adverse health consequences, mercury advice is not being communicated to the public effectively or accurately

How much tuna can I eat a week before I need to worry about mercury?

Most forms of mercury are potentially very toxic to humans. But to make matters worse, a substantial proportion of mercury in fish is present as methylmercury – a potent neurotoxin formed by bacteria in waters and sediments. Although mercury pollution has increased since industrialisation, accumulation of methylmercury in animals is a completely natural phenomenon.

How My Mercury Level Hit Double the Safety Limit

Fortunately, for a man, mercury contamination isn’t considered a significant health risk — and my levels are still well below the point at which harm would likely occur. But women who are pregnant or want to get pregnant, as well as very young children, are a different story; those groups are more vulnerable to mercury contamination. The reason is that mercury is a neurotoxin that impairs brain development in young children, either directly or through a pregnant or nursing mother.

How poisonous mercury can get from coal-fired power plants into the fish you eat – Trump’s EPA plans to weaken emissions rules meant to lower the risk

Mercury is a neurotoxic metal that can cause irreparable harm to human health – especially the brain development of young children. It is tied to lower IQ and results in decreased earning potential, as well as higher health costs. Lost productivity from mercury alone was calculated in 2005 to reach almost US$9 billion per year. One way mercury gets into river fish is with the gases that rise up the smokestacks of coal-burning power plants.

How to Eat All the Fish You Want, Minus the Mercury Danger

Fish: It’s one of the most confusing topics among health-conscious eaters. On one hand, it’s a great source of protein and healthy fat, and eating it has been linked to lower rates of several illnesses, including heart disease and Alzheimer’s. Then again, some types are full of mercury or other pollutants. It seems like one day we’re told to eat less fish, and the next, to eat more.

How to Tell If You're Poisoning Yourself With Fish

Scientists have assured me that one serving of halibut contains nowhere near a dosage that might cause harm. These are the same scientists, though, who admit that no one knows for sure what the threshold dose is that causes mercury to subtly poison cells in the brain and the liver, two organs where it tends to accumulate.

How Worried Should I Really Be About Mercury in Tuna?

Tuna is awash in helpful nutrients like iron and omega-3 fatty acids—not to mention delicious in sushi, salads, and sandwiches—but it is also known for one ingredient that’s not so beneficial: mercury. That means with every bite of bigeye steak, you might be ingesting a tiny little bit of that naturally occurring heavy metal too. Sounds scary, but what does this really mean for your health? Could eating a spicy tuna roll for lunch once a week actually come with safety hazards? How about every day? Basically, how worried should you really be about mercury in tuna?

Mercury Contamination of Seafood

Mercury contamination of seafood is a persistent public health threat that poses a significant risk to children and women of child-bearing age. While some mercury is naturally occurring in the environment, activities such as the burning of coal for power generation and industrial processes, such as battery manufacturing, have redistributed the substance and created mercury compounds that are toxic even at extremely low levels of exposure.

Mercury in Fish, Seafood May Be Linked to Increased ALS Risk

While a growing body of evidence from previous studies has pointed to mercury as a risk factor for ALS—in the U.S., primarily through eating fish contaminated with the neurotoxic metal—the exact cause of the disease is still unknown.

Mercury in seafood

The best way to reduce exposure to methylmercury is to reduce your consumption of predatory or long-lived fish (such as swordfish, shark, orange roughy and tuna). Be especially conservative if you are a woman of childbearing age or are feeding young children.

Mercury in Seafood: A Little Clarity

One of the most dangerous yet confusing toxic pollutants is mercury in seafood. Mercury is very bad for developing fetuses and children, and seafood is very good for them. But mercury is in all seafood. Like I said: confusing.

Mercury Myth: Self Magazine Misses the Point

Self magazine recently published an extensive article titled “How Worried Should I Really Be About Mercury in Tuna?” At almost 2,000 words it’s a behemoth of a report. It’s pretty clear the reporter did a lot of research and provides at least some balance on a retread topic that’s primarily driven by unnecessary hand wringing and hyperbole.

Pollution triples mercury levels in ocean surface waters, study finds

Toxic metal threatens marine life as it accumulates faster in shallow layers than in deep sea due to human activity

Some Fish Are Still Full of Mercury, for a Worrying Reason

Emissions of mercury have declined, but levels in fish could still increase thanks to overfishing and a changing climate.

Study Links Mercury Levels In Fish To Coal-Fired Power Plants

As if you needed another reason to cringe at the number of coal-fired power plants operating on our fragile Earth, a new study published in Nature Geoscience links power plants in China and India to the ever-increasing mercury levels of fish in the Pacific Ocean.

Sugar-coated Mercury Contamination

Most of us know by now that eating mercury is bad for you, and we know that mercury contamination is a risk in certain types of fish. But did you know this neurologically damaging heavy metal could also be lurking in everything from cereal to ketchup?

The Threat of Mercury Poisoning by Fish Consumption

Fish meat has a high nutritional value. It is high in protein and monounsaturated fats, but pollution is causing more and more fish species to contain mercury. Communities that consume a variety of fish species in their daily diet may be exposed to serious illnesses as a result of methylmercury poisoning, owing to a lack of knowledge or disregard for warnings, assuming that the quantity of mercury in fish intake is insignificant. Although the risk of low doses of mercury is modest on an individual basis, this should not prevent us from taking proper measures. The consequences of today’s progress will have a long-term influence on the whole population. To safeguard future generations’ health, mercury must be phased out internationally and replaced with safer alternatives, and people must be better informed about how to avoid mercury buildup in their bodies.

US Seafood Advice Flawed on Mercury, Omega-3s

People who follow the federal government’s guidelines on seafood consumption are likely to consume too much mercury, a dangerous neurotoxin, or too few beneficial omega-3 fatty acids, according to a new EWG analysis of fish contaminant and nutrient data.

What to do about mercury in fish

Fish is an excellent source of protein, and its healthy oils protect against cardiovascular disease. Because a diet rich in seafood protects the heart and aids neurological development, fish remains an important component of a healthy diet. However, nearly all fish and shellfish contain traces of mercury, a toxic metal, and some seafood contains other contaminants known as persistent organic pollutants (POPs).