The highest is Watari District in Fukushima City, close to 20,000 becquerels/kg of radioactive cesium. Kashiwa City in Chiba and Ichinoseki City in Iwate, about 200 kilometers south and north of Fukushima I Nuclear Power Plant respectively, also tested rather high, with close to 6,000 becquerels/kg of radioactive cesium.
ACRO used Osaka as control.
No mention of whether other nuclides were tested or found.
From ACRO press release on December 15, 2011:
ACRO has analysed dust of vacuum cleaners from 13 dwellings. Excepted Osaka, chosen as a reference because it is located 600 km from the plant, all dust samples are contaminated with cesium 137 and 134 following the catastrophe of Fukushima.
It is in the district of Watari of Fukushima-city that the contamination is highest with almost 20,000 becquerels per kilogram for both cesium. This district, located about fifty kilometres from the plant, is known to be particularly contaminated and the sale of rice is prohibited.
Homes are also significantly contaminated in Ichinoseki in Iwate province to the north and in Kashiwa in Chiba to the south, situated in the northern suburbs of Tokyo. In both cities, located about 200 km of the plant, contaminated dust is nearly 6,000 becquerels per kilogram.
We don’t know from when the dust was collected by the vacuum cleaners. In Japan, one removes shoes before entering home.
(H/T anon reader)