Radiation levels as high as those in the evacuation zone around the Fukushima Daiichi nuclear power plant, that were detected in Kashiwa, Chiba Prefecture, last month, were likely caused by the disaster, Environment Ministry officials said Tuesday.
The hotspot, a small area of about one meter radius, was found in a vacant lot in Kashiwa. Radiation levels of 4.11 microsieverts per hour were detected one meter above the surface of the soil, equivalent to some areas in the evacuation zone around the crippled nuclear power plant. Up to 450,000 becquerels per kilogram of radioactive substances were detected in the soil below the surface, an Environment Ministry official said, Fuji TV reported.
The area is located some 195 kilometers from the accident site.
Inspectors believe the hotspot was created after radioactive cesium carried by rainwater became concentrated in a small area because of a broken gutter.
A Kashiwa city official said the area had been covered with sand and plastic sheets, which so far have lowered the radiation levels in the air, Fuji reported.
Variable winds, weather and topography result in an uneven spread of contamination from the nuclear plant, experts say, and radioactive elements tend to concentrate in places where dust and rain water accumulate such as drains and ditches.
As researchers carry out tests to map how far contamination has spread from the plant, radiation fears are a daily fact of life in many parts of Japan following the earthquake and tsunami-sparked meltdowns at the plant, with reported cases of contaminated water, beef, vegetables, tea and seafood.© Japan Today