{"id":10194,"date":"2011-09-28T10:53:31","date_gmt":"2011-09-28T10:53:31","guid":{"rendered":"http:\/\/scienceblogs.com\/gregladen\/2011\/09\/28\/japan-nuclear-disaster-update-13\/"},"modified":"2011-09-28T10:53:31","modified_gmt":"2011-09-28T10:53:31","slug":"japan-nuclear-disaster-update-13","status":"publish","type":"post","link":"https:\/\/gregladen.com\/blog\/2011\/09\/28\/japan-nuclear-disaster-update-13\/","title":{"rendered":"Japan Nuclear Disaster: Update # 36: Sushi Recommendations"},"content":{"rendered":"

One of the interesting items we have this week is a study by Greenpeace in which various organisms from the sea near Fukushima were sampled for radioactive isotopes. Let’s take a closer look.<\/p>\n

The data in the table provided (see the first item in Ana’s feed for the link) show the amount of radiation (radioactive decay) by isotope type per kilogram of plant or animal tissue from various samples. On the higher end is a fish with 357 bq\/kg of radiation and some seaweed with 190 bk\/kg.<\/p>\n

What does this mean? Hard to say. I can tell you this: A normal human has about 4,000 or more bq (in total for the human) of radiation primarily from the most common source of radiation (radioactive potassium) So if Greenpeace had sampled a typical human not from a radioactive region they would get a result of about 4,000 bq total. Say a human weighs 70 kilos. That means the human being sampled would yield about 50 bk\/kg. So the radioactive fish is about 7 times more radioactive than a human, and the plant almost 4 times as radioactive. A concern here would be where on the food chain one is, if radioactive isotopes are being concentrated through trophic activity (things eating things). Also, a concern would be how long this radioactive stuff will be radioactive.<\/p>\n

Regarding the second question first, roughly half the radioactive material found in the Greenpeace samples has a half life of just over 2 years, but the rest has a half life of 30 years. Regarding trophic level, note that among the less radioactive samples both fish and seaweed have similar amounts, but among the more radioactive samples, it is the fish (which are trophically higher than plants) that have more, which simply indicates that the samples could be revealing things about a real biological system (subject to revision). In other words, were the reverse true, I’d be scratching my head and not because of dandruff.<\/p>\n

The most radioactive fish is a Rockfish, which is an opportunistic carnivore often feeding on other things that eat things and sometimes things that eat things that eat things, and they are probably relatively long lived. In other words, rockfish are high on the food chain and would be expected to concentrate radioactive isotopes that are in the environment. The next highest fish in terms of contamination is the halibut, which is also a carnivore, but eating more crustaceans and probably not as high on the food chain. A kind of cod, with a similar diet to halibut is next. The lowest in terms of radiation is a kind of mackerel, which probably eats pelagic crustaceans (shrimpy things that float around near the surface) which in turn eat plankton. This would be the lowest on the food chain of the sampled fish, but also the highest in the water column. So, it might be hard to tell the difference here between how high something is on the food chain and how high (top feeder) vs low (bottom feeder) the fish is in the water column. My sushi recommendations? Surface feeding low-torphic level short lived fish. From the Atlantic Ocean.<\/p>\n

None of these samples were particularly close to the power plant, some were purchased from markets some taken directly from the sea. The plume of radiation from the plant is rather large<\/a>.<\/p>\n

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Scan Ana’s feed for a lot more on contamination issues.<\/p>\n

And as these data become available we also see bans on Japanese produce being lifted for US military commissaries. The effects of food bans are being explored, and radioactive contamination is being found in novel places such as industrial waste.<\/p>\n

News regarding nuclear plant incidents, construction patterns, and potentials in the US, as well as further conversations about nuclear safety, are all over Ana’s feed. And it’s OK, the IAEA has a plant to make reactors safe. They also have this barn door they intend to close. The plan will be voluntary, of course.<\/p>\n

Meanwhile at the reactors, water has been used to cool them down to the point where the hot spots are only barely boiling and bubbling. In other words, we are still in a state where Step One control over the situation has not yet been achieved, even though it was declared achieved weeks ago. It is now expected that cooling below boiling levels may be achieved by some time next year.<\/p>\n

It does appear that rainwater is passing more or less feely into the lower levels of the nuclear power plant where it interacts with uncontrolled globs of nuclear material, then presumably disappears from the planet all on its own. Or perhaps it flows into the nearby sea. They’re still working on that.<\/p>\n

I want to take a moment to express my very sincere thanks to Analiese Miller for the tremendous work she does in putting together this feed. I know that she’s been very busy with other things over the last few weeks and that this has been an extra burden on her. You are awesome, Ana.<\/p>\n

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Ana’s Feed<\/h2>\n
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Evaluation on the Environmental Consequences in Japan of the Fukushima Nuclear Power Plant Accident -Greenpeace International, Sept. 8 <\/h4>\n
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