Wednesday, May 25, 2011

An expert from the Nuclear Waste Management Organization of Japan has calculated more alarming radioactive contamination estimates for the surrounding Fukushima area

With Tepco releasing reliable data the way Enron disclosed its financials on the way down, independent experts have felt compelled to calculate and come forward with various estimates of their own. At a recent policy setting meeting with the Japan Atomic Energy Commission, Dr. Tomio Kawata, utilizing whatever reliable isotope release data he could get his hands on (the non-Tepco variety), shed further light on how heavily contaminated the soil is in areas northwest of the plant.

"According to Kawata, soil in a 600 square kilometer area mostly to the northwest of the Fukushima plant is likely to have absorbed radioactive cesium of over 1.48 million becquerels per square meter, the yardstick for compulsory migration orders in the 1986 Chernobyl catastrophe.

Kawata also said soil in a 700 square km area is likely to have absorbed 555,000-1.48 million becquerels per square meter, which was a criteria for temporary migration during the Chernobyl disaster.

Kawata estimated the soil contamination using data on radiation levels in the air monitored by the Ministry of Education, Culture, Sports, Science and Technology.

The size of the contaminated areas in the Fukushima crisis is one-tenth to one-fifth of those polluted in the Chernobyl disaster, Kawata said.

While the expected radiation exposure from 1.48 million becquerels of cesium is around five millisieverts a year, below the government’s benchmark of 20 millisieverts for evacuation orders, decontamination will still be necessary before evacuees can return as radioactive cesium binds strongly to soil, making it hard to reduce radiation levels, Kawata said."

Since this seems to be as legit as the Fukushima-Chernobyl comparisons get, let's pull up a map of the Chernobyl control-zone to get a visual idea of Dr. Kawata's numbers and their implications:

1.48 million Becquerels/m² = 40 Curies/km²

600 km² of area in the Fukushima Prefecture have radioactivity equivalent to the confiscated/closed zones on this map (red).  An additional 700 km² of area fit the "permanent control zone" criteria (dark pink), as it stands in Chernobyl today.

Edit:  Here's a recently released French IRSN map based on MEXT data.  This map breaks down the isotope concentration in the Fukushima and surrounding area:


How long will it take for Cs-137 to work it's way out of the environment?  Considering the Chernobyl situation further, we can see from the following chart that a long, slow slog in dose rate reduction is ahead for Japan as well. Measurements are in air, with Cs-137 as the main contributor.

Source: Wikipedia

Read the original story here


  1. Comparisons of Chernobyl and Fukushima are fruitless,apples and oranges.The entire matter is quite simply a deflection technique implemented to obscure data,and downplay the severity of the situation.The crisis in Japan is terribly bad and worsening each day,and cesium 137,and 134 are only the "the tip of the iceberg" as far as the overall contamination that is being released into the environment.

  2. The MEXT data on which the IRSN map is based is certainly suspect. Remember, MEXT is the governmental agency that's done nothing but lie to the Japanese people since the Fukushima crisis began.

    The largest cities in Fukushima Prefecture, Fukushima City (pop. 290,000) and Koriyama (pop. 339,000), could have ground contamination levels well above those of the voluntary Chernobyl evacuation zone and quite possibly above the mandatory one (thus they would be in the green or even yellow zones on the MEXT/IRSN map).

    Here's how I arrived at that conclusion:

    Greenpeace volunteers ( found soil in Fukushima City and Koriyama with the following levels of contamination:

    Fukushima City: 55150 Bq/kg (April 7)
    Koriyama: 32980 Bq/kg (April 8)

    Using the 20x and 65x conversion methods described in, we get surface area contamination levels of:

    Fukushima City: 1.1M-3.6M Bq/m2
    Koriyama: 659,600-2.14M Bq/m2

    Thus, surface contamination in both cities could exceed the mandatory Chernobyl evacuation level of 1.48M Bq/m2. And it most certainly exceeds the 185,000 Bq/m2 of the Chernobyl voluntary evacuation zone.

    At minimum, the Soviet government offered the residents of such areas the option of relocating, with compensation. Will Japan do the same?

  3. R002

    One thing to keep in mind with the comparison is a large portion of the contamination at Fukushima went into the ocean. I haven't heard a whole lot of the various ocean testing results. I guess it's a good thing the Japanese don't depend on the sea ...oh, wait.

    Here a good book if you can find it:

    "Environmental Radioactivity From Natural, Industrial and Military Sources" by Merril Eisenbud

    ISBN: 0-12-235153-3

  4. This might be why there isn't a whole lot of ocean sampling.

    "Tokyo, Japan, 26 May 2011 – Greenpeace today slammed the Japanese authorities’ continued inadequate response to the Fukushima nuclear crisis, after new data from its radiation monitoring showed seaweed radiation levels 50 times higher than official limits, raising serious concerns about continued long-term risks to people and the environment from contaminated seawater. In contrast, Japanese authorities claim that radioactivity is being dispersed or diluted (1) and are undertaking only limited marine radiation monitoring."

  5. Whoa. 20 km out and activity is that high in seaweed?

  6. The NW contamination plume is from the SFP#3 prompt criticality explosion. If you look at the contamination map most of the hottest spots are in a NW direction away from #3.

  7. Fukushima; Pacific Ocean Catastrophe Confirmed; via A Green Road Blog

    Fukushima Leaking Radioactive Water Into Ocean Plume; via A Green Road Blog

    Comparing Contaminated Zones Around Chernobyl And Fukushima Ocean Radiation Released; via A Green Road Blog

    93 Long life Radiation Contaminants, A Problem For Billions Of Years; via A Green Road Blog

  8. To my knowledge, serial ultrasound for right lower quadrant abdominal pain has not been investigated. Radiation badge

    As I mentioned in the blog, some centers are adopting protocols to reduce the radiation dose of CT. Also, limiting the CT to focus on the area of the appendix would help.