On March 11th, 2011, the Fukushima Daiichi Nuclear power plant was hit by natural forces that were beyond its capability to withstand. It all started with the Tōhoku earthquake, approximately 70 kilometers east of the Oshinka Peninsula. This was the most powerful earthquake in the history of Japan and the fourth most powerful on record, measuring 9.1 on the Richter scale.
This earthquake was so powerful that it moved the Japanese island of Honshu 2.4 meters to the East, shifted the Earth’s axis between 10 and 25 cm, increased the earth’s rotational speed slightly and created a tsunami with waves as tall as 40.5 meter (133 feet) that struck eastern Japan.
Looking at it dispassionately, it’s not surprising that the earthquake damaged the nuclear power plant. But that would have been a survivable accident, were it not for the other effects of the earthquake and resulting tsunami. Recognizing the danger, systems in the active reactors immediately shut down form the earthquake, a pre-programmed response to protect the people of Japan. But nuclear reactors generate an enormous amount of heat, and the tsunami disabled the generators which should have provided power to the pumps necessary to cool the reactors.
Without those pumps in operation, three of the reactors melted down, there were hydrogen-air explosions and radioactive material in three of the reactors was released into the environment. Contamination is continuing, seven years later, as groundwater seeps into the damaged reactors and mixes with the radioactive material.
It was the loss of cooling, more than anything else which led to the massive damage caused by the nuclear power plant’s destruction. The meltdown of the reactors themselves, which included the meltdown of the nuclear materials, allowed those refined nuclear materials to sink into the ground, below the containment built to house the reactor. Today, scientists are unsure exactly how far below ground the radioactive material is, but are estimating that it is between the reactor and the underground aquifers that the Japanese people depend on.
This accident has been rated as a level 7 nuclear event on the INES (international nuclear and radiological event scale), the highest rating that can be applied. Only one other nuclear accident has been considered to be severe enough to receive this rating, Chernobyl.
Contamination From The Accident
The Fukushima Daiichi Nuclear Power Plant is located on the eastern coast of Japan, guaranteeing that an accident of this severity would affect the Pacific Ocean. This contamination started almost immediately, with the operators of the power plant releasing overheated coolant water into the ocean in an effort to prevent a more serious accident. In addition, radioactive gas was released from the pressure vessels, in an effort to reduce the chances of explosion.
About 19 pounds of caesium-137 entered the ocean in the following months. However, this was not the only radioactivity to reach the ocean water. Even today, rainwater flowing over the contaminated ground is washing more radiation into the sea, as well as the ongoing contamination of groundwater beneath the site. How much that interacts with the ocean water is not clear at this time.
The ocean currents off the coast of Fukushima are some of the strongest in the world, spreading this contamination far into the Pacific Ocean. It is hard to judge just exactly how far this has spread, as there has been a constant stream of fear-mongering propagated by environmental groups. While it is clear that the radiation has spread, and even spread far enough to reach the western coast of the United States, the levels of contamination are very low.
Monitoring by the Preparatory Commission for the Comprehensive Nuclear Test Ban Treaty Organization (CTBTO), an anti-nuclear power agency, has picked up radioactive isotopes at over 40 monitoring stations, including in the southern hemisphere. However, even though caesium isotopic concentrations off the coat of Japan being 10 to 1000 times above the norm, radiation levels are still below the level that is considered dangerous to marine life and human consumers.
It is important to note, that to date, there have been no deaths or illness attributed to radiation from the Fukushima Daiichi Nuclear Power Plant, other than those which were attributed to the original accident, which were mostly caused by the tsunami, not the power plant accident.
What This Means For Our Tuna
Tuna is one of the more prolific fish worldwide, growing and being harvested in both the Atlantic and Pacific oceans, with more coming out of the Pacific Ocean. Many Pacific Tuna are born off the eastern coast of Japan, where they are guaranteed to spend at least part of their lives swimming through water with at least some radioactive contamination. These fish are highly migratory and will swim thousands of miles in their lives.
If you believe the fear mongers, the radiation levels in the Pacific Ocean are so high, that one would expect the fish to be glowing. But they are not. As with much fear mongering, the scope of the problem is being magnified exponentially. Any radiation at all is being reported as major concentrations, confusing the issue for the sake of politics.
Albacore Tuna caught off the shores of Washington and Oregon were found to have some contamination suspected of coming from the Fukushima accident. But you would have to eat 700,000 pounds of the fish they examined with the highest radiation level, to match the amount of radiation the average person is exposed to annually from our environment.
In other words, while any tuna you eat today is likely to have swum in waters which have been contaminated by the Fukushima accident, it really doesn’t matter. The levels of contamination are so low, regardless of what some people are saying, that the fish you eat won’t contain enough radiation to affect your health at all. In fact, you’d get more radiation out of eating a nice fresh banana, than you will from eating the canned tuna sitting on your supermarket shelf.
So don’t worry about stockpiling tuna. It’s not going to make you start glowing and you’re not going to start having two-headed kids. Or if you do, at least it won’t be the tuna’s fault.
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