Armed with his geiger counter, the Ministry of Education's radiation map and the Professor Hayakawa's radiation contour map, he went measuring radiation levels in Koriyama City on December 23, and they were high.
Air radiation level at chest height: maximum 1.51 microsievert/hour
On the sand on the side drain cover: 42.85 microsieverts/hour
If the surface radiation is that high, it would be several hundreds of thousands of becquerels/kg of radioactive cesium in that sand. No one does a thing, and life goes on, because all the national and municipal governments care about is air radiation at 1 meter off the ground.
But even if you stay outside in 1.51 microsievert/hr radiation all day all night for one year, it would only be 13 millisieverts of external radiation. Nothing to worry about, according to the new Japanese government guideline crafted by the panel of expert scientists picked by the government (in order to obtain precisely the guideline).
Never mind that until March 11, Koriyama City's air radiation was probably below 0.06 microsievert/hour like anywhere else in northern Japan, and that's how it has been for the residents for generations.
(H/T Aloha Analytics)