Tokyo: A radiation hotspot has been detected in Tokyo, reports said on Thursday as researchers carry out stringent tests to map how far contamination has spread from the crippled Fukushima nuclear plant.
Japanese media said researchers found radiation levels of 3.35 microsieverts per hour along a street in the west of the capital -- 220 kilometres (136 miles from Fukushima – much higher than previously reported levels.
According to calculations based on the Japanese Science Ministry`s criteria, the equivalent annual dose in the hotspot would be 17.6 millisieverts, just below the 20 millisieverts per year threshold that requires evacuation.
The reading is also higher than levels measured recently at Iitate, an area in Fukushima prefecture that has been evacuated.
The reading in Setagaya was taken one metre above the ground near a hedge, national broadcaster NHK said, while other parts of the same sidewalk showed lower readings.
The reading came after ward authorities said yesterday that levels of 2.7 microsieverts per hour had been detected on October 06, higher than levels of less than 0.1 microsieverts in other parts of Setagaya according to official data.
The higher readings come as more tests illustrate how far fall-out from the Fukushima disaster have spread, with elevated levels of radioactive caesium recently found as far away as Yokohama, more than 241 kilometres (150 miles) from the plant.