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Understanding Fukushima

Posted by Malcolm on September 7, 2013

In order to rant about Fukushima and the radioactive mess that is occurring the Pacific Ocean, it is important to understand the nature of radiation, the benefits (or issues) with maps, and the nature of the problem. In March of 2011, an earthquake struck off the coast of Japan and the resulting tsunami overwhelmed the seawalls. During the earthquake the Fukushima Dai-ichi nuclear plant lost outside power and faced degraded safety systems. The tsunami then hit, resulting in explosions in 4 units of the facility, 1 of which was never able to achieve cold shutdown, i.e. it continues to leak radiation. Part of the issue is that the facility had noticeable safety flaws that were never addressed, but the unpredictable nature of natural disasters was the main issue. Recent news articles have begun to highlight the new high levels of radiation leaking from the plant.

This NOAA map represents the height of the tsunami wave that swamped the Fukushima Dai’ichi nuclear plant in 2011, NOT the extent of radiation flowing outward from the spill.

While researching for the Green Rant this week I had to give myself a thorough refresher over radiation and its impacts on people and nature. Radiation is complex and one could spend their entire life studying it and still not understand it. There are a few terms that need clarification to understand the issue unfolding in Japan. First is the peach amount of radiation from the plant of about 2,200 millisieverts/hour. Sieverts (Sv) are a measure of the biological impacts of a radiation dose. For example, there are about 2.5 mSv/year of typical background radiation from natural sources and one sievert carries with it a 5.5% chance of eventually developing cancer. The next term is the amount of radiation that will reach the CA coastline (and is being diluted throughout the Pacific) of 10-20 becquerels/cubic meter. Becquerels (Bq) are a measure of radioactive decay and have no implications on biological impacts. Radiation, in the form of cesium-137 and strontium-90 (the isotopes radiating from Fukushima), have similar properties to potassium and calcium respectively. This means that they are able to bioaccumulate in in cells of animals and in bones (again respectively).

A major issue with the fallout of Fukushima is the maps that are being distributed on the internet. The map to the right has been used to demonstrate the radiation in the Pacific. The map actually displays wave height from the tsunami and not radiation. As mentioned, there is a trace amount of radiation that will reach the west coast of the US (and all of the Pacific) that is better demonstrated in a series of maps found here.

The biggest concern right now is that we are now unable to eat fish in the Pacific due to the radiation. Technically, the levels are not high enough to have serious health impacts. I would be more concerned about the sustainability concerns and the mercury levels.