FUKUSHIMA--The Fukushima municipal government is apparently not following its own proposal for decontaminating homes polluted by radioactive materials or guidelines called for by the Environment Ministry.
Water used in pressurized sprayers to clean the roofs of homes and roads has been allowed to flow into gutters.
Guidelines established by the Environment Ministry call for efforts to collect as much as possible the runoff from the cleaning of roofs.
Moreover, the Fukushima municipal government submitted a proposal to the ministry that designates the use of bags containing zeolite and sandbags to filter radioactive materials out of the water used to clean homes and roads. However, the city has so far not utilized that method except in a small percentage of cases.
"With difficulties in finding a temporary storage place for the contaminated sandbags, we chose to emphasize reducing radiation levels in residential areas," explained one Fukushima city official in charge of the decontamination process. "Because there has been an increase in temporary storage areas, we plan to implement the method in the future."
Environment Ministry officials said they thought that the filtration system was being used in Fukushima city.
Fukushima city is not one of the 11 municipalities over which the Environment Ministry has direct jurisdiction to decontaminate polluted areas. The Asahi Shimbun broke a story on Jan. 4 that found shoddy decontamination work in three of those municipalities.
However, other municipalities, such as Fukushima city, are conducting decontamination work at their own initiative. In areas where the annual radiation level is 1 millisievert or higher, which translates into 0.23 microsieverts per hour, the central government provides subsidies for the decontamination work conducted by the municipality.
Almost the entire city of Fukushima has radiation levels that call for such subsidies. About 90,000 households are eligible for such decontamination work. So far, decontamination has been completed on about 4,000 households.
In tests conducted on the filtration system proposed by Fukushima city, about 90 percent of the cesium was filtered out of the water through the use of the zeolite-filled bags and sandbags. Last September, the Environment Ministry approved the payment of subsidies for the use of that filtration system.
In meetings with local residents, Fukushima municipal government officials explained that the filtration system would be used. They asked the companies that actually conducted the decontamination work to use the system from those areas where temporary storage areas for the bags were found.
However, city officials admitted that the method has only been used for about 300 households in 10 neighborhoods in eastern Fukushima city.
Experts have raised doubts about the effectiveness of using pressurized sprayers to decontaminate roofs. They have said that wiping the surfaces with a cloth was much more effective in removing radioactive materials.
"There are many residents who ask that the pressurized sprayer be used because it ends up looking cleaner," one city official handling decontamination said.
One individual handling the actual decontamination work raised doubts about the guidelines established by the Environment Ministry.
"Because large amounts of radioactive materials have already flowed into sewers and rivers through the wind and rain, I do not think there is much meaning to collecting the polluted water from the decontamination work," the on-site inspector said.
Experts have also raised questions about processing the polluted water that emerges from decontamination using pressurized sprayers.
Junichiro Tada, an executive with the Radiation Safety Forum, a nonprofit organization that is involved in decontamination work in Fukushima Prefecture, said, "I do not think there is a large effect on the environment even if (the wastewater) is not filtered."
He said there was a much larger effect from radioactive materials that have flowed into gutters or rivers during heavy rains.
At the same time, he said, "There is the question of morals if they promised citizens that they would filter the water."
Tada also raised doubts about the limits placed on municipalities that are trying to decontaminate through the Environment Ministry guidelines.
"The pressurized sprayers that are included in the Environment Ministry's guidelines go against the objective of decontamination because radioactive materials are splattered in surrounding areas," he said. "There are more than a few items in those guidelines that do not fit the reality that those doing decontamination work actually face."
Kunihiro Yamada, a professor specializing in environmental design at Kyoto Seika University, has proposed his own decontamination methods to local governments in Fukushima Prefecture.
"From the standpoint of those actually doing the work, it is impossible to collect all of the polluted water, and there are also limits to the areas to which that collected material can be kept," Yamada said.
He said rather than use pressurized sprayers, a combination of foam cleansing, brushing and absorbing the materials should be used to decontaminate areas of radiation.
(This article was mostly compiled by Masakazu Honda.)
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