The Yomiuri Shimbun
SENDAI--Mt. Hiyori, regarded as the nation's second-lowest mountain at 6.05 meters high, was washed away by the March 11 tsunami, it has been learned.
The tsunami washed away not only the shortest official mountain in Miyagino Ward, Sendai, but also a reed field in the Gamo wetlands where wild birds such as snipes and plovers rested. Consequently, numbers of wild birds in the area have fallen sharply since the disaster.
According to a civic group working to protect the Gamo wetlands, about 50 species of bird are usually observed at this time of year. However, only 28 species were recorded in a survey on the area they took on Sunday.
According to the Sendai municipal government and other sources, Mt. Hiyori was the second-lowest mountain in the nation, behind the 4.53-meter-high Mt. Tempo in Osaka, based on a map issued by the Geospatial Information Authority.
A Geospatial Information Authority official said the body would decide what course of action to take regarding the mountain being featured on its map after checking aerial photos and information from local governments.
The mountain, which was quite easy to walk around, was believed to have been made by local residents around 1909. It overlooked Sendai Bay and was loved by local residents as a place to relax. Some residents have expressed disappointment for having lost the mountain.
An 81-year-old man from Miyagino Ward who used to live near Mt. Hiyori said: "I've not come here for a long time and I'm so surprised to see [the mountain] is totally gone. I regret the loss of the mountain, which made for the best playground when I was a child."
(Sep. 16, 2011)
Friday, September 16, 2011
16/09 Sunflowers no help for decontamination efforts
The Yomiuri Shimbun
Authorities trying to decontaminate radioactive soil in the aftermath of the accident at the Fukushima No. 1 nuclear power plant have found that sunflowers, despite their reputation for absorbing radioactive cesium, have little effect, an experiment has shown.
The experiment was conducted by the Agriculture, Forestry and Fisheries Ministry. Following the outbreak of the nuclear crisis, a large amount of radioactive substances were released, contaminating the areas around the plant.
Although the experiment found that scraping away the surface of the contaminated soil is effective to reduce the density of radioactive cesium, this method leaves the problem of how to dispose of a large quantity of contaminated soil.
The experiment on removing radioactive cesium started in May in farmland totaling 7,000 square meters in Iitatemura and other locations in Fukushima Prefecture.
In the experiment, the effects of the following four methods were examined: scraping away surface soil; washing contaminated soil with water and removing the water; burying topsoil and replacing it with subsoil; and using sunflowers and other plants to absorb radioactive cesium in soil.
The results showed the least effective of the four methods was the use of plants.
Sunflowers, which were planted in May and bloomed in August, absorbed only 520 becquerels, or about 0.05 percent, of about 1.07 million becquerels of radioactive cesium per square meter of contaminated soil.
When four centimeters of topsoil was scraped away, the density of radioactive cesium was reduced by up to 75 percent. When three centimeters was scraped away from pastures with green grass, the density was reduced by up to 97 percent.
While switching topsoil and subsoil reduced the density of cesium on the surface, the amount of radioactive cesium remained unchanged.
The central government restricts rice growing in paddy fields with soil containing more than 5,000 becquerels of radioactive cesium per kilogram.
In Fukushima Prefecture alone, there are about 8,300 hectares of rice and vegetable fields in which radiation levels were found to exceed the government-set limit. If the topsoil of all the fields is scraped away, about 3 million to 4 million tons of contaminated soil is expected to be removed.
Based on the experiment's results, the ministry intends to finance the removal of cesium-contaminated soil in the prefecture with reserve funds and the third supplementary budget for this fiscal year.
As it is an enormous task to scrape away such a large amount of soil, the ministry is expected to coordinate with local governments on decontamination efforts.
(Sep. 16, 2011)
Authorities trying to decontaminate radioactive soil in the aftermath of the accident at the Fukushima No. 1 nuclear power plant have found that sunflowers, despite their reputation for absorbing radioactive cesium, have little effect, an experiment has shown.
The experiment was conducted by the Agriculture, Forestry and Fisheries Ministry. Following the outbreak of the nuclear crisis, a large amount of radioactive substances were released, contaminating the areas around the plant.
Although the experiment found that scraping away the surface of the contaminated soil is effective to reduce the density of radioactive cesium, this method leaves the problem of how to dispose of a large quantity of contaminated soil.
The experiment on removing radioactive cesium started in May in farmland totaling 7,000 square meters in Iitatemura and other locations in Fukushima Prefecture.
In the experiment, the effects of the following four methods were examined: scraping away surface soil; washing contaminated soil with water and removing the water; burying topsoil and replacing it with subsoil; and using sunflowers and other plants to absorb radioactive cesium in soil.
The results showed the least effective of the four methods was the use of plants.
Sunflowers, which were planted in May and bloomed in August, absorbed only 520 becquerels, or about 0.05 percent, of about 1.07 million becquerels of radioactive cesium per square meter of contaminated soil.
When four centimeters of topsoil was scraped away, the density of radioactive cesium was reduced by up to 75 percent. When three centimeters was scraped away from pastures with green grass, the density was reduced by up to 97 percent.
While switching topsoil and subsoil reduced the density of cesium on the surface, the amount of radioactive cesium remained unchanged.
The central government restricts rice growing in paddy fields with soil containing more than 5,000 becquerels of radioactive cesium per kilogram.
In Fukushima Prefecture alone, there are about 8,300 hectares of rice and vegetable fields in which radiation levels were found to exceed the government-set limit. If the topsoil of all the fields is scraped away, about 3 million to 4 million tons of contaminated soil is expected to be removed.
Based on the experiment's results, the ministry intends to finance the removal of cesium-contaminated soil in the prefecture with reserve funds and the third supplementary budget for this fiscal year.
As it is an enormous task to scrape away such a large amount of soil, the ministry is expected to coordinate with local governments on decontamination efforts.
(Sep. 16, 2011)
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