Folloiwing up on I-131 and Cs-137 fallout, a new assessment from the IAEA:
Based on measurements of I-131 and Cs-137 in soil, sampled from 18 to 26 March in 9 municipalities at distances of 25 to 58 km from the Fukushima Nuclear Power Plant, the total deposition of iodine-131 and cesium-137 has been calculated. The results indicate a pronounced spatial variability of the total deposition of iodine-131 and cesium-137. The average total deposition determined at these locations for iodine-131 range from 0.2 to 25 Megabecquerel per square metre and for cesium-137 from 0.02-3.7 Megabecquerel per square metre. The highest values were found in a relatively small area in the Northwest from the Fukushima Nuclear Power Plant. First assessment indicates that one of the IAEA operational criteria for evacuation is exceeded in Iitate village. We advised the counterpart to carefully access the situation. They indicated that they are already assessing.
I posted a similar conclusion 3 days ago. This subject was already in the news 5 days ago, and the original data was available to the Japanese ministry MEXT 10 days ago (although they delayed its public release).
IAEA links to a copy of their "Criteria for Use in Preparedness and Response for a Nuclear or Radiological Emergency". My guess is that the criterion is in table 3, effective dose (E) of 100 mSv per annum, suggesting "temporary relocation".
AFP is reporting on this:
The International Atomic Energy Agency said safe limits had been exceeded at Iitate village, 40 kilometres (25 miles) northwest of Fukushima, well outside the government-imposed 20 kilometre exclusion zone and the 30-kilometre "stay indoors" zone.