It turned out that Yokohama city government had received the report of the measurement of Strontium-90 in mid September.
It was asked in the city council but an “expert” of Yokohama City University ,Inoue Tomio asserted that additional measurement is not needed because the air dose is low.
It is impressive that the “expert” did not even know strontium-90 emits beta radiation.
Having the advice, Yokohama city government declined additional measurement of Strontium.
Successfully, strontium got the permanent residency in Yokohama.(Source)(Source)
Also, the news broadcasting organization IWJ run by Iwakami Yasumi, which reported measurement of strontium, was banned to attend the press conference of Yokohama city “government”.
Probably plutonium will be found in Tokyo or Yokohama soon.
However, it is highly likely they will not do anything to protect the citizens.
The video below is the athletic festival of a kindergarten in Yokohama held in October.
The soil around shows 0.95 uSv/h.
http://www.youtube.com/watch?v=E8QjDdjqTX8