Real radioactive cleanup from Fukushima area is a long way off

With challenges such as the designation of temporary radioactive waste dumps and interim storage facilities yet unsolved, the road to true decontamination remains a long one.

True radiation decontamination still a long way away, Mainichi Daily News,. Japan October 7, 2011 Though the government last month lifted the “emergency evacuation preparation zone” designation of some areas greatly affected by the ongoing crisis at the Fukushima No. 1 Nuclear Power Plant, radiation decontamination efforts are still taking place in areas with high levels of radiation.

The three main decontamination methods that have been highly publicized through media reports are: the stripping away of surface soil from school playgrounds and athletic fields, the removal of mud accumulated in gutters, and the washing of roofs using high-pressure water cleaners. While the first method is considered effective, the remaining two have been found to be effective only to a certain point, and some especially warn against overestimating the effects of high-pressure water cleaners.

“It might make you feel like you’re decontaminating, but there’s a limit to the amount of radioactive cesium that’s caked onto roofs that can be eliminated with high-pressure water cleaners,” says Kunihiro Yamada, a professor of environmental science at Kyoto Seika University. “The water cleaners wash surface dirt off, but then that tainted water goes into sewers and can contaminate rivers, thereby affecting farm goods and seafood. If people in highly populated areas were to begin using water cleaners, we may end up finding people forcing tainted water onto each other.”

Since his launch of the “Radiation Contamination and Recovery Project” with colleagues from Fukushima University and Osaka University in May, Yamada has been running trials in the city of Fukushima on methods of decontamination that residents can undertake themselves. He has compiled a manual, which is available on the website of the Society for Studies on Entropy, an organization of which he is a representative.

What exactly is meant by the “limitations” of high-pressure water cleaning, a method that is featured in manuals available from both the central government and the Fukushima Prefectural Government?

According to Yamada, radioactive cesium is believed to exist in three states: dissolved in water, loosely bonded to organic materials such as moss and leaves, or tightly bonded to rock such as silicate salt. In other words, if soil is removed and washed away with high-pressure water cleaners, radioactive cesium found in surface soil and gutters can be eliminated. The cesium that has become affixed to roofs remains, however.

At the request of Fukushima residents and civic groups, on Sept. 14, Kobe University Professor Tomoya Yamauchi, a radiation metrology specialist, measured radiation levels in Watari, which was believed to have some of the highest radiation levels in the city of Fukushima. At a building used for afterschool activities for elementary school children, Yamauchi found 0.33 microsieverts of radiation close to the floor, while radiation levels near the beams and the ceiling were 0.52 microsieverts and 0.72 microsieverts, respectively. Near the concrete roof tiles, radiation levels were at 1.74 microsieverts……

Both Yamada and Yamauchi agree that children and pregnant women living in areas that have not been subject to evacuation orders but have nonetheless been found to have high levels of radiation — like the cities of Fukushima and Koriyama — should be evacuated temporarily, and that those areas be thoroughly decontaminated while those populations are away. Kodama also says that residents living in areas with yearly radiation exposure of 1 millisievert or higher who want to evacuate should be fully supported by the government and Tokyo Electric Power Co., the operator of the stricken power plant.

Kodama finishes his book, “Naibu hibaku no shinjitu” (The Truth about Internal Exposure), with the following: “We have contaminated our country’s earth, this irreplaceable inheritance from our ancestors that we had been charged with and must pass on to our children. However, if humans are the ones who contaminated it, then we humans should be able to clean it up again.”

With challenges such as the designation of temporary radioactive waste dumps and interim storage facilities yet unsolved, the road to true decontamination remains a long one.

http://mdn.mainichi.jp/features/news/20111007p2a00m0na018000c.html