Saturday, March 1, 2014

Fresh Water Reservoirs Contaminated in Japan Up to 390,000 Becquerels per kilogram in Soil

Japanese Government declares its not responsible for decontaminating reservoirs in residential areas not classified as evacuation zones:
Health risk or not? Cesium levels high in hundreds of Fukushima reservoirs. SHINICHI FUJIWARA February 25, 2014

[excerpted] A joint survey by the prefectural government and a branch office of the farm ministry found that the levels exceed 8,000 becquerels per kilogram of soil in 576 reservoirs. In 14 of those cases, the level tops 100,000 becquerels. The central government says that reservoirs, many of which are located in residential areas, are not covered by its decontamination program

The survey covered 1,939 reservoirs, or slightly more than half of the 3,730 in Fukushima Prefecture for agricultural use. Prefectural authorities, fearing that contaminated mud from the reservoirs may reach farmland and create a health hazard for residents, is asking the central government to remove the waste. 

Contaminated soil exceeding 8,000 becquerels corresponds to designated waste that must be removed  at the central government's initiative.

…. Of the 14 reservoirs where cesium contamination exceeds 100,000 becquerels, nine are located in evacuation order zones. The remaining five are situated outside those areas. The highest contamination level of 390,000 becquerels was detected in the Ominamisaku reservoir in the town of Futaba ... [end]

Majia here: The two problems with Japan's evacuation and clean-up programs are:

1. The plan does not address hot-spots and re-contamination

2. The plan makes people responsible for their own clean-up in areas designated as producing less than 20 millisieverts a year in exposure.

Here is an excerpt from a chapter I'm working on exploring how Fukushima crisis management shifts risk to citizens:

Many Japanese citizens are dis-satisfied with the proposed evacuation and compensation plans, arguing in particular that areas with external exposure levels at 20 millisieverts a year and more are unsafe for human habitation. Moreover, many are concerned that they are being forced by economic necessity to return to contaminated areas where local clean-up will be slow and ineffective and that new measurement devices for atmospheric levels will understate actual contamination. 

De-contamination has not gone smoothly. Fraud and corruption have been pervasive and decontaminated areas have been quickly re-contaminated. [i] 

Responsibility for financing and executing decontamination has been highly contested because local communities are often held responsible for executing and paying for decontamination.

In August 2011 Japan passed the “Act on Special Measures Concerning the Handling of Radioactive Pollution” , which delineates responsibility for clean-up. The Ministry of the Environment is designated as responsible for categorizing contamination zones. Two zones of contamination were carved out by the act. 

First is the ‘Special Decontamination Area,’ for which the Japanese government is responsible for clean-up.[ii] It includes 11 municipalities in the (formerly) restricted zone or planned evacuation zone with less than 20 kilometers from the NPS. It encompasses areas with cumulative doses in excess of 20 millisieverts a year. 

Second is the ‘Intensive Contamination Survey Area,’ for which local governments are responsible for clean-up, although they are supposed to have access to financial and technical supports from the national government. The Intensive Contamination Survey area includes land from 104 municipalities where the dose rate is over 0.23 Sv/h (equivalent to over 1 mSv/y of additional dose), but less than 20 millisieverts a year.[iii]

The problem is that these designations assign local responsibility for de-contamination in areas under 20 millisieverts a year when the international standard is one and they fail to anticipate the long-term dispersion and bio-accumulation of radionuclides in the environment. 

Communities simply do not have the resources to de-contaminate properly, resulting in storage of radioactive waste (including dirt and leaves) in bags in close proximity to living spaces. 

Moreover, fallout distribution of radionuclides such as radiocesium, uranium and plutonium is not uniformly homogeneous, nor is it static. Radionuclides in the water or attached to dust and pollen in the atmosphere circulate in plumes, depositing concentrations variably depending upon geographic and atmospheric conditions. Radionuclides also circulate as they are absorbed by flora and inhaled and ingested by fauna. Bio-accumulation and bio-magnification amplify concentrations in animals high on the food chain, such as humans. 

De-contamination is a never ending process that has yet to be successfully mastered, as clean-up at Hanford in the US illustrates. The Japanese government’s policy responses to clean-up and evacuation have essentially transferred many of the costs and risks of de-contamination areas to local officials and citizens.


[i] For example, T. Kihara and M. Aoki (17 January 2013) ‘Crooked Cleanup: Photos, Videos Show Contractors Lied in Decontamination Reports’, The Asahi Shimbun,

[ii] Ministry of the Environment (2013 September 16) Progress on Off Site Clean Up Efforts,

[iii] Ministry of the Environment (2013 September 16) Progress on Off Site Clean Up Efforts,

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