Radioactive cesium not detectable in 99% of Fukushima residents: study


Radioactive cesium was too low to detect in 99 percent of 22,000 residents examined in Fukushima Prefecture and neighboring Ibaraki, according to a University of Tokyo survey.

The team, which included professor Ryugo Hayano, examined internal radiation exposure levels in the two prefectures between March and November 2012. Their findings were unveiled Wednesday in the Transactions of the Japan Academy.

The survey found that the rate of internal exposure in the residents surveyed stood at about one-hundredth of the level detected in people living in the area around the Chernobyl plant at the time of the 1986 disaster.

Levels of cesium-137 were shown to be below the detectable threshold of 300 becquerels per kilogram of body weight for 99 percent of the residents, according to the team.

For the remaining 1 percent, or 212 people, 10 becquerels were detected. Still, their annual internal exposure would total only 0.04 millisievert, far below the government-set limit of 1 millisievert per year, the team said.

Meanwhile, cesium levels equivalent to 1 millisievert of internal exposure at an annualized rate were found in four elderly people who routinely ate wild mushrooms and boars. The team confirmed that the figures dropped after these four changed their eating habits.

Just as with the Chernobyl crisis, soil, particularly around Fukushima, was heavily contaminated with radioactive substances following the March 2011 nuclear meltdowns at the Fukushima No. 1 power plant.

The low cesium readings were attributed to the quality of the soil in the areas surveyed, which prevented food crops from absorbing radioactive materials, the conduction of radiation checks for food and the attention local residents are paying to the produce they consume, according to Hayano.

But the team, which used a whole body counter to examine the residents, concluded that checks on internal exposure and food inspections need to be continued. The study was conducted jointly with a hospital in Fukushima Prefecture.

  • thedudeabidez

    Given the gakubatsu (old-boy) clique of Todai grads that includes TEPCO management, LDP members, METI bureaucrats, Keidanren leadership, academic commentators in the media who regularly downplay the nuclear issues, and let’s not forget the toothless Nulcear Safety Commission itself, well, it’s best to take any report emerging from Tokyo University as suspect until proven otherwise. TEPCO’s own figures report 760,000 tetrabecquerels of Cesium-137 discharged into the atmosphere, more than quadruple the amount released by Chernobyl. How this translates into 1/100th the exposure of Chernobyl-area populations is not explained by this article.

    Also, Mr. Hayano is not an expert on nuclear power, nor is he a medical doctor— his specialty is experimental nuclear physics.

    Furthermore, the hospital in Fukushima that participated in the study was not named, but there are many, many reports from Fukushima residents suffering from sudden and unexplained symptoms who go to the hospital and from the outset, the doctors refuse to even discuss the idea that they might be radiation-related. They may or may not be, but the refusal to even consider the issue given the known contamination is shocking. Twitter is full of such stories. It would seem a conclusion had already been reached and now we are seeing “data” manufactured to support it.

    • Michael Radcliffe

      Hey, why do university studies at all when we have twitter, right?

    • Masa Chekov

      It could be the largest conspiracy ever – the Japanese government, titans of industry, hospitals, officials at all levels, all in collusion, for what reason who knows – or Twitter could be wrong.

      I’ll vote on Twitter being wrong, thank you. Not to mention mainstream scientific thought agreeing broadly with the conclusions of this report.

      I think some of you are hoping for a bunch of misery just so you’ll be right.

    • GMainwaring

      “It would seem a conclusion had already been reached and now we are seeing “data” manufactured to support it.”

      You know, I actually agree with this statement of yours. However we would disagree on which side of the debate is manufacturing their “data”.

    • Sam Gilman

      Gio, the questions you’ve raised about this report have not been put honestly.

      You suggest that all work coming out of Tokyo University is suspect because some people who graduated from there occupy executive positions in industry and government. But you’ve been living in Japan for a long time. You *know* that Tokyo University is the top university in the country, one of the top in Asia and in the world top 50 (and by the by, ranked 14th for physics). Just like Oxbridge and the Ivy League in the UK and US, it tends to produce graduates who go on to take leading roles in government and industry. Should we suspect all graduates of Yale of being folksy warmongers just because George Bush went there? Would you prefer that the investigation had been led by someone from a much lower quality university? What kind of sense would that make?

      You also argue that Ryugo Hayano does not have the correct breadth of expertise, as if his expertise in atomic physics is the only expertise on the team. Was it beyond you to track down the other authors? It took me less than five minutes. They include a physician from Fukushima prefecture who has been involved in radiation assessments since the beginning of the crisis, as well as a radiation specialist at Fukushima Medical university and doctors from Hirata Central hospital. Your complaint that this hospital is not named is the fault of the Japan Times. Given your evident passion on the issue, is tracking down the abstract of a recently published, open access, newsworthy study really beyond you? Ironically, I found the link on Ryugo Hayano’s twitter feed.

      Your figures for the amount of caesium-137 released appears to rely on you or someone else misreading a viral and really poor Russia Today report which itself manages to misread the TEPCO figures it tries to discuss, in particular failing to understand what peta- and tera- prefixes mean, and swapping atmospheric and oceanic releases. So they get the wrong Cs-137 figures, and they are then wrong by a factor of a hundred.

      The thing is, we know that Russia Today is not a reliable source on Fukushima. (I thought everyone knew that. It gave pretend expert Arnie Gundersen loads of airtime). If you’re relying on RT, or worse, on a website that recycled it, then you’re not taking things seriously. We all know that there are people on all sides spouting rubbish about radiation. Instead of being happy to find sources that support your view, the more honest thing to do is base your views on what is reliable. Go to the source, and don’t trust journalists. They get science wrong in simple ways all the time.

      Lastly you reveal – for someone so convinced of the dangers of the releases – an astonishing ignorance of what medical symptoms radiation might produce. Radiation is not witchcraft, or a generator of all diseases. Radiation below very high levels (ie of the order of a whole Sievert that can cause acute radiation sickness) does not produce “sudden” symptoms. It results in things like cancers, often of very unusual kinds, such as thyroid cancers, that take years to develop. If you’re honestly concerned about the health impacts of Fukushima, surely you would have found time to read up on this. Google search is free.

      The thing is, when people turn up at the doctor’s, complaining of symptoms that look for all the world like stress and not a bit like cancer or any other radiogenic conditions, the doctors are quite right to say “this is not something that is caused by radiation”. They will be keen to minimize the stress because it can lead to depression, alcoholism, strains on families (with children picking up behavioral problems – all of which we can see already and has been reported on). They’re not denying anyone’s rights.

      Given that all professionally scrutinized studies by respected, mainstream scientists are concluding – as established experts from around the world have been suggesting since the beginning of the crisis – that the ultimate risk to the population from the releases is likely to be very small, where is all this destructive stress coming from? Gio, I’m afraid it’s from people like you. People who carelessly sow doubt and fear through social media without any thought of the consequences. Tweets are a better source of science than trained medical and radiological experts experts in the field? Twitter? What kind of silliness is that?

      Please, please, if you want to engage in critical analysis of sources on this issue, do it honestly. Don’t just settle on what you think you already know. That’s not honest.

  • spectral_ev

    You could read this as 1 in 100 people tested had evidence of internal exposure to radiation. Not good when you consider the lifetime effects of radiation damage.