TOKYO — Radiation levels as high as those in the evacuation zone around the Fukushima Daiichi nuclear power plant have been detected in a Tokyo suburb, and are likely linked to the disaster, officials said Monday.
In the latest sign that radioactive material has spread far beyond the Fukushima Daiichi nuclear plant, officials said the contaminated area in Kashiwa, about 125 miles from the plant, likely resulted from cesium-laced rain that fell soon after the March 11 disaster.
Similar to a number of other such spots found in the metropolitan area recently, the latest discovery was prompted by a local resident toting a dosimeter who noticed a spike in its reading. The incident was soon reported to a community leader, who took the reading with monitoring equipment and alerted the city.
Kashiwa, located 18 miles northeast of Tokyo, has a population of 400,000 people.
City officials have found contamination levels as high as 57.5 microsieverts per hour in the soil, sparking radiation fears in the neighborhood some 195 kilometers from the accident site.
Inspectors from the science and technology ministry believe the hotspot was created after radioactive cesium carried by rainwater became concentrated in a small area because of a broken gutter.
“The numbers we found last week were way above what we could imagine based on what we had learned in the past,” said an official at Kashiwa city’s radiation safety division, who asked that his name not be disclosed.
“We will cooperate with the government to find the cause and to decontaminate the spot.”
“We covered the area with river sand and plastic sheets, which so far have lowered the radiation levels in the air,” said another quoted Kashiwa city official.
“We will decide what to do with the contaminated spot after discussing it with officials,” he said.
Prompted by calls from parents, the city has kept an eye on radiation levels in schools and playgrounds since the March 11 disaster, and officials said they knew that Kashiwa had become a “hotspot.”
Masahiro Fukushi warned citizens Monday that more hot spots can be found where rainwater accumulates, like near the ditch in Kashiwa, and urged them to go out and take readings of such places in their neighborhoods on their own, instead of waiting around for the government’s plodding surveys.
“As we now have the knowledge of where we can find hot spots, such as areas under downspouts, we should work together to monitor such places,” he said. “I think this is where citizen volunteer efforts must come into play.”
The soil at the hot spot had a high 276,000 becquerels of cesium per kilogram, the Kashiwa Municipal Government said. This is four to five times higher than the level surrounding the hot spot and many other places in Kashiwa, he said. The condensation process will allow this level to be attained in any place where rainwater accumulates in a limited area, Fukushi said.
Many are wondering if the rainwater HADN’T seeped through the hole in the gutter and concentrated in the soil, then where would this highly-radioactive rainwater have gone. Didn’t this same rain fall on the entire city of Tokyo as well as everywhere all around it? Why would that not be cause for further concern?
Contamination in much of Kashiwa is far higher than other parts of the Tokyo metropolitan area, so the mini hot spot really wasn’t much of a surprise, said Fukushi, a professor of radiation science at Tokyo Metropolitan University.
“If the (cesium) detected was 100 times higher than the amount measured by the science ministry, then it’d be strange. But in this case, it’s just four or five times, so you should not be surprised,” Fukushi said.
The leader of a Citizens’ Group to Protect Children from Hotspot Radiation in Kashiwa city, Chiba, decided to suspend its activities. Mrs. Yuki Ohsaku, representative of the group evacuated recently to Kyushu after her two children started nosebleeding and other core members also are considering moving out of Kashiwa city. 10 members have already relocated.
The government will NEVER announce for people to evacuate. The reasons for this are at least two-fold. Reason #1 is that they will need to pay for the evacuation of the people and reason #2 is that once the evacuations begin it would impact the greater Tokyo area and thus the Japanese economy.
Compost handled by students at an agricultural high school in Tochigi Prefecture contained 74 times more radioactive cesium than the government’s safety standard.
The Tochigi prefectural board of education said on Oct. 17 that 29,600 becquerels per kilogram of radioactive soil had been found in compost used at the Tochigi Agricultural High School in Tochigi city, far above the government maximum of 400 becquerels per kilogram.
The Forestry Agency has decided to allow local governments to use plots of land in state-owned forests to temporarily store soil and rice straw contaminated with radioactive substances from the crippled Fukushima No. 1 nuclear power plant. Local governments will be responsible for preparing the land for the temporary storage sites, while the central government will shoulder the cost using its reserve fund for reconstruction.
The Forestry Agency will start checking for radioactive substances in cedar pollen in Fukushima Prefecture as early as next month. The agency plans to pick male cedar flowers in the no-entry zone and check them for radioactive cesium, it said.
There will be many more similar hotspots discovered as they continue looking for them.
In addition to the rain carrying the radiation all over East Japan, there are many other routes for unidentified contamination to be transferred across the country. The problem with radiation is that it never shows up where you expect it to, and even the smallest effects, like flying insects from the Fukushima area that are eaten by birds, can have an unforseen effect. While in any other circumstance with ‘popular isotopes’ (Iodine and Cesium) this would be a nominal event, in Fukushima a laundry list of the most volatile and long lived isotopes have been released. The bugs eat the plants, bioaccumulate more of these harsher isotopes including Plutonium, and suddenly even a few internalized particles can become a potential risk to the public as these isotopes bioaccumulate and biomagnify up the food chain.