From Kyodo News:
High levels of radioactive cesium were found in an area that used to be used as a waterway near an elementary school in Yokohama's Seya Ward, Yokohama city officials said Friday.
Local officials detected 6.85 microsieverts per hour of radioactive cesium in the air about 1 centimeter above the ground and found that nearby soil contained 62,900 becquerels of the element per kilogram.
The city government sees the high radiation levels to be likely caused by the nuclear crisis at the Fukushima Daiichi power plant and plans to decontaminate the area, the officials said.
While the area is close to the elementary school, it is closed off by a fence, the officials said. "The radiation dose on the elementary school premises is not high but we will examine the situation in detail," an official said.