Following up this article..14 μSv/h from the yellow substance on the roof in Kashiwa Chiba
High level of cesium was measured from the yellow substance by becquerel monitor (TS100B-15). [Link]
Date : 8/18/2012
Cs-137 : 107627.2±264.1 Bq/Kg
Cs-134 : 69312.6±287.4 Bq/Kg
Total : 176939.8±390.3 Bq/Kg
The spectrum is like this below.
After dehydration, it was 20 μSv/h on the sample. [Video]
Iori Mochizuki