Compared the highest atmospheric dose in each prefecture (apart from Fukushima), the highest prefectures are (from the highest)
1. Tochigi
2. Miyagi
3. Ibaraki
4. Chiba
5. Saitama
6. Gunma
7. Iwate
The data was taken on 6:00AM 5/12/2012.
The source is Monitoring information of environmental radioactivity level of Ministry of Education, Culture, Sports, Science and Technology. [Link] [Summary]
There are several monitoring posts in each prefecture, this is the comparison of the highest readings in each prefecture to suggest the worst hot spot.
The highest reading in Tochigi is Nasushiobara on the map below.
It’s 113.5 km away from Fukushima plants.
