Your Tuna is Getting More Toxic!
Date: Friday, May 22 @ 12:28:32 EDT
Topic: Your Tuna is Getting More Toxic!
The rate of mercury contamination in tuna and other Pacific fish has increased 30 percent since 1990. The increase is a direct result of China''''s rapid industrialization, and the mercury content is expected to increase another 50 percent by 2050 if China continues to build more coal-fired power plants.
The data comes from a new study by the U.S. Geologic Survey. About 40 percent of all U.S. exposure to mercury comes from eating contaminated tuna from the Pacific. Roughly 75 percent of all human exposure to mercury in general comes from eating fish. Mercury poisoning early in life, even in very small amounts, can lead to permanent developmental effects. Mercury becomes toxic when it is converted by bacteria into a form called methyl mercury. Scientists have long known how this conversion takes place in freshwater lakes, reservoirs and rivers, but this study is the first to doc ument how that conversion takes place in the ocean. It shows that methyl mercury is produced in mid-depth ocean waters by bacteria decomposing settling algae.
The Daily Green May 6, 2009
Global Biogeochemical Cycles May 1, 2009
Many of you are likely now aware that most fish, whether from streams, lakes, oceans or farm-raised, is contaminated with mercury and other toxins. What may be a surprise is just how much mercury contamination has increased in recent years -- 30 percent since1990, with another 50 percent increase expected by 2050.
Further, a full 75 percent of all human exposure to mercury comes from eating fish, U.S. officials say, with 40 percent of that from contaminated Pacific tuna alone.
Why is So Much Mercury Contaminating Our Oceans?
According to this latest research, the large increases are due to rapid industrialization in China, where they are constructing as many as one new coal-fired power plant a week.
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 methyl mercury, where it finds its way into fish, acc umulating especially in fish that are higher up the food chain.
Fish like tuna, sea bass, marlin, and halibut show some of the worst contamination, but dozens of species and thousands of water bodies have been seriously polluted.
Asia is a growing part of the pollution problem, as winds carry the airborne toxins over the ocean, where it rains down. Ocean currents also carry the pollution throughout the basin. The United States is also a major contributor; 40 tons of mercury are released into the United States alone every year due to burning coal to generate electricity.
Mercury is Toxic for You and Your Family
People who regularly eat fish have higher levels of methyl mercury than those who dont, which is concerning, considering that methyl mercury toxicity can result in paresthesia (a tingling sensation on your skin), depression, and blurred vision.
In fetuses and developing infants it can also have negative effects on attention span, language, visual-spatial skills, memory and coordination.It is estimated that nearly 60,000 children each year are born at risk for neurological problems due to methyl mercury exposure in the womb.
Even in low doses mercury can interfere with a childs 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.
Mercury is especially damaging to your central nervous system (CNS), and studies show that mercury in the CNS causes psychological, neurological, and immunological problems including:
Slowed mental response
To make matters worse, mercury bonds very firmly to structures in your CNS. Unless actively removed, mercury has an extremely long half-life of somewhere between 15 and 30 years in the CNS!
Should All Tuna be Avoided?
Tuna is a popular fish in the United States, both in canned form and at sushi restaurants. In 2007, canned tuna was the second most eaten seafood, with the average American eating nearly three pounds of it that year.
However, tuna can grow to be extremely large. Blue fin tuna, for instance, can weigh up to 550 pounds, and because they eat many, many small fish to grow that large, tuna may be among the most mercury-contaminated seafood out there.
In fact, laboratory tests in New York released in 2007 found so much mercury in tuna sushi that two or three pieces a week at some restaurants could be a health hazard. Plus, 10 percent of the tuna samples were unsafe for all consumers, because they contained mercury levels above 1.0 ppm, which is the legal action limit for fish sold in the U.S.
Even canned light tuna, which is touted as a safer, lower mercury seafood choice, can be unsafe. Six percent of cans tested contained more than 0.35 ppm, and as much as 0.85 ppm. White or albacore canned tuna had an average of 0.35 ppm.
If you eat a lot of fish during pregnancy, or even as little as a single serving of a highly contaminated fish, you can expose your developing child to excessive levels of mercury. The toxic metal can cross through your placenta to harm your childs rapidly developing nervous system, including your babys brain.
So if you are pregnant or nursing, or planning to become pregnant, you should be very careful about eating fish. Some fish are more problematic than others. These are some of the ones you should definitely avoid if you are pregnant or nursing:
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 tuna or any fish -- unless you have lab results in your hand that can attest to its purity.
How to Get the Health Benefits of Fish Without All the Risk
Just because fish in the 21st century are nearly universally contaminated, that does not erase your genetic requirement for omega-3 fats. Just get them by taking a high-quality krill oil or fish oil, instead of risking your health by eating contaminated fish.
Eating smaller fish, like anchovies and sardines, is also an option, as their small size makes them far less likely to be contaminated.