Decontamination in the prefecture

Latest reference:

Environmental Remediation　in Affected Areas in Japan(Dec., 2018 Ministry of Environment, Japan) 

Progress in decontamination

   Air radiation levels in the prefecture have significantly decreased compared to April,  2011.  Decontamination of prefectural land has been completed in all areas except for the Difficult-to-return zone.

 

Decontaminated zones and summary

Legend	Zone name	Agency	Summary
：Light blue	Special decontamination area	National Government	The "former planned evacuation zones" where the annual integral dose may exceed 20 milisievert (mSv) and the "former warning zones" located within 20 km of the Fukushima Daiichi Nuclear Power Station.
：Red frame	Priority contamination survey area	Municipality	Municipality including areas where the annual additional exposure dose exceeds 1 mSv
：Brown	Municipalities where the decontamination plan is in effect	Municipality	Municipality where a decontamination plan was drawn up and is in progress

Progress in decontamination conducted by national governmental agencies P.9-11 (Ministry of the Environment: Decontamination data website)

Progress in decontamination in all the municipal areas to be decontaminated (36 municipalities)

Actual progress in decontamination compared to planned number by the end of FY2017(March 2018)

In Fukushima Prefecture, some areas are decontaminated by national governmental agencies and other areas are by municipal agencies.

What is decontamination?

Decontamination is to reduce the amount of radiation received in the living areas by removing radioactive materials or by burying them underground.

Reduction of environmental radiation dose involves decontamination achieved by a combination of three methods, "removal", "blocking", and "keeping it away at a distance."

• "Removal" of soil and vegetation contaminated with radioactivity
• The removed soil and vegetation contaminated with radioactivity are then covered with uncontaminated soil "to block" the radiation.
• These removed contaminated materials are taken away from where people are living.

Reference: "Decontamination and Radiation Q&A" on the Decontamination Information Plaza homepage (Fukushima Prefecture, and Ministry for the Environment)

Decontamination methods and the effects

”Off-site Environmental Remediation in Affected Areas in Japan”　August 2020 [PDFファイル／7.49MB] 出典：環境省ホームページ（http://josen.env.go.jp/en/）

Decontamination method

*Decontamination Activities in Tamura City

Wiping off rooftop and walls	Wiping off a gutter
High pressure water cleaning of a drain pipe	High pressure water cleaning of paved road
Mowing and removal of sludge	Removal of crushed stones and topsoil, and covering with clean soil

*Before & After the Decontamination Work in Tamura City

Effects of Decontamination in SDA

The chart shows the air dose rate average in each category (aggregated data of measuring points).

Residential areas include schools, parks, cemeteries, and large-sized facilities, farmland includes orchard, and forests includeslopes, grasslandand lawn. 

Post-decontamination monitoring was implemented after 6 months to a year after the decontamination work. The latest result of post decontamination monitoring in municipalities were summarized

[Implementation period]

・Monitoring before decontaminationNov.2011 -Nov. 2016

・Monitoring after decontaminationDec. 2011 -Dec. 2017

・Post decontamination monitoringOct. 2014 -Aug. 2018