Japan will more than triple the number of regions it checks for airborne radiation as more contaminated “hot spots” are discovered far from Tokyo Electric Power Co.’s crippled Fukushima nuclear power station.
The government said it will increase radiation monitoring by helicopter to 22 prefectures from the six closest to the plant, which began spewing radiation after an earthquake and tsunami struck the station in March. The plan comes after radioactive waste more than double the regulatory limit was found 200 kilometers (125 miles) from the plant this week.
Authorities have refused to give a cumulative figure for radiation released from the Fukushima Dai-ichi nuclear plant after estimating in June that fallout in the six days following the quake was equal to 15 percent of total radiation released in the Chernobyl nuclear disaster in 1986. The authorities have been too slow to widen airborne radiation testing, said Tetsuo Ito, the head of Kinki University’s Atomic Energy Research Institute in Osaka.
“The government should have expanded the monitoring area by helicopters much earlier to ease concerns among the public,” Ito said in a telephone interview yesterday.
Officials on Aug. 12 found compost in a kindergarten yard in Tokamachi city, Niigata prefecture containing radioactive cesium measuring 27,000 becquerels per kilogram, Kenichiro Kasuga, an official at the city’s disaster prevention department, said by phone.
Under Japanese law, waste measuring over 8,000 becquerels per kilogram must be treated as radioactive waste and can’t be buried in a landfill.
City officials found sludge measuring 18,900 becquerels per kilogram from radioactive cesium on the same day as part of tests done at 60 educational and childcare facilities, Kasuga said. The city government is storing the waste in drums until the government sets final guidelines for its disposal, he said.
“We still don’t know why this level of cesium was found in the compost,” Kasuga said.
The hotspots in Niigata were likely caused by wind blowing northwest towards the prefecture in the days following the Fukushima accident, Kinki University’s Ito said.
The government will begin monitoring radiation levels in 16 prefectures from Aomori, in the far north of the main island of Honshu, to Aichi in central Japan 460 kilometers (290 miles) from the plant by the end of October, the Ministry of Education, Culture, Sports, Science and Technology said in a statement on its website yesterday.
Radiation monitoring has taken place in four other prefectures and in Gunma and the western part of Fukushima prefecture, said Hirotaka Oku, a spokesman at the science and technology ministry.
Checks in Ibaraki and Yamagata prefecture were completed in August and the findings will be released soon, he said, without specifying when.
The discovery of radiation at Niigata kindergartens coincides with the start of the rice harvest in the prefecture that was the country’s biggest producer last year with 7 percent of the total. Radiation from Dai-Ichi has already been found in food including beef, tea and spinach.
So far, early tests on rice haven’t detected radiation, Shingo Gocho, assistant director in Niigata prefecture’s agricultural division said by phone yesterday. The government is taking samples from 45 areas in 29 villages, towns and cities that make up the prefecture’s growing area, he said. The crops won’t be shipped until the results are known, he said.
Japan’s Ministry of Health, Labour and Welfare plans to conduct radiation checks in food produced in about 100 cities, towns and villages in 14 prefectures because local governments hadn’t tested produce by the end of July despite requests by the central government, said an official at the ministry, who declined to be identified, citing internal rules.
The central government will become move involved in testing food to ease concerns among consumers and provide more data, the official said. Radiation checks on produce including vegetables, meat and eggs will be carried out at the National Institute of Health Sciences and the findings will be released as soon as possible, the official said.
Tokyo Electric’s Dai-Ichi plant released about 770,000 tera becquerels of radioactive materials between March 11 and March 16, Japan’s Nuclear and Industrial Safety Agency said on June 6.
Japan’s government is under-reporting the amount of airborne radiation across the country, said Tom Gill, an anthropology professor at Meiji Gakuin University in Tokyo, citing his studies in Fukushima prefecture since March.
The “maximum” radiation level given for Fukushima prefecture on Aug. 13 was 2.64 microsieverts per hour in the village of Iitate 40 kilometers northwest of the Dai-Ichi plant, Gill said, according to figures from the Science Ministry published daily in national newspapers.
That compares with the official reading in the village itself the next day of 14.2 microsieverts per hour, he said, showing a picture he took of the reading on that day. He was speaking at a presentation in Yokohama near Tokyo on Aug. 19.
The government excludes the highest readings among 20 measuring stations in the village from the data it collates for publication, Gill said.
“Distrust and cynicism of central government is pretty much universal across Fukushima now,” he said.
Medical tests on children living in three towns near the plant between March 24 and 30 found 45 percent of those surveyed suffered low-level thyroid radiation exposure, Japan’s government said earlier this month.
Children are more susceptible to poisoning from radioactive iodine, which can accumulate in the thyroid and cause cancer, according to the World Health Organization. None of the children’s thyroid glands exceeded the safety threshold of 0.2 microsievert per hour set by the Nuclear Safety Commission of Japan, the government said at the time.
The Fukushima disaster is the worst since a reactor exploded at Chernobyl in the former Soviet Union 25 years ago. About 2 million people in Ukraine are still under permanent medical monitoring, according to the nation’s embassy in Tokyo.
A becquerel represents one radioactive decay per second, which involves the release of atomic energy that can damage human cells and DNA, with prolonged exposure causing leukemia and other forms of cancer, the World Nuclear Association says.