Tuna Brings Radioactive Contamination To US
Love tuna? You may be in for a nasty surprise, as your tuna might be radioactive! Contaminated Bluefin tuna, one of the fastest-swimming fish in the world, have traveled to US shores all the way from Japanese waters. They are believed to carry radioactive substance from last year’s Fukushima Dai-ichi disaster during the earthquake-triggered tsunami in March. Researchers are currently working hard to understand the phenomenon and figure out how to mitigate this serious situation. The only saving grace in the whole picture is that radioactive levels in these fish are still way below the permissible levels in the US.
1) Starting from Japan
When disaster hit Japan, one of the major casualties was the Fukushima nuclear reactor, which leaked radioactive substances into the environment, including the ocean and affecting smaller fish and plankton across Japanese waters. However, nobody expected the nuclear fallout to reach all the way to American shores, through huge fish such as the Bluefish Tuna. Such a large fish is usually capable of metabolizing the radioactive substances out of its system. However, this species has failed to do so and ended up carrying the nuclear fallout across the Pacific into the US.
2) Scientists are Stunned
Researchers were startled by this occurence. Nicholas Fisher, one of the scientists researching these fish, says, “That’s a big ocean. To swim across it and still retain these radionuclides is pretty amazing.” Scientists are worried that with so much radioactive contamination still present in the Bluefish tuna, the nuclear fallout along the Japanese coast was actually much worse than they originally thought. This is because while swimming east, the predators should have shed some radiation as they metabolized it out of their system and grew bigger. Since they are still radioactive after their oceanic journey, their original contamination levels must have been extremely high.
3) The Experiments
Weighing more than 450kgs each, Bluefin Tuna traveled 10,000kms from the Japanese coast towards California and Mexico. Five months after the Fukushima disaster, a team of scientists tested the Pacific Bluefin, which had been caught off the San Diego coast. The fish showed the presence of cesium, a radioactive substance, at an amount up to 10 times higher than previous levels. The findings of the study were also reported in the “Proceedings of the National Academy of Sciences.” The scientists collected 15 tissue samples from 15 different tuna fish and each one contained higher than usual levels of cesium-135 and cesium-137. When similar experiments were carried out in yellowfin tuna, which grows in the eastern Pacific, as well as in Bluefin tuna that had migrated to the US before the Japanese disaster, it was found that none of the fish showed any radioactive traces. This led the scientists to declare unequivocally that “Fukushima was the source” of radioactive contamination of Bluefish tuna now traveling across the Pacific.
4) What Now?
Bluefin Tuna found in the Pacific is a prize catch in Japan, which consumes about 80% of the world’s Bluefin Tuna. This is one of the reasons why, at the onset of the Fukushima disaster, EU decided to test all Japanese food imports. However, with the passage of time, things were forgotten. This current radioactive contamination is still being dismissed as nothing more than a warning sign. The good news, however, is that scientists are going to continue studying larger samples of Bluefish tuna to better understand the radioactive phenomenon. Then they will be able to predict conclusively whether the US population needs to be worried about it or not.
Until these results are released, I'd advise steering clear of Pacific Bluefin Tuna, just to be safe!
Image Courtesy: csmonitor.com
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