Food and radioactivity, a good read

There is a very good and clear blogpost on Daily Kos about radioactivity in food, and I recommend reading it if you want to know more.  It also reprinted this excellent description of the difference between being 'exposed' to 'contaminated', from a Vermont brochure:

If you have a manure pile and you are close enough to smell it, you are exposed. If you go across the road to your neighbor’s house you will not expose or contaminate them. If, on the other hand, you also step in the manure, you are now contaminated. If you go across the road to your neighbors’ house without decontaminating your shoe or boot, you will expose your neighbors and probably contaminate their house. It you do contaminate your neighbor’s house, they may also contaminate themselves. 

Radiation is similar. An exposed but uncontaminated person or animal does not pose a risk to other people or animals. Contamination can be detected with radiation meters. External contamination can be removed by vigorous washing with soap and water.

This catastrophe in Japan brings back memories of the Chernobyl accident ('Tjernobyl' in Swedish) in 1986, during my last year of high school in Sweden.  The day or two after it happened me and friends were scheduled to leave for a birding trip to Hungary during spring break, but since we didn't know where the radioactive cloud would land we aimed for southern France and the Camargue delta instead. We had no books, plans, or maps for southern France, but we couldn't risk going to a place that might mean we got radioactive dust on us.  

When we came back to Sweden all cars wheels were checked with Geiger counters at the border, and we found out that the cloud had changed direction and hit the Baltic countries and Scandinavia.  For many years thereafter you could (=should) not each wild mushrooms, berries, and reindeer meat from northern Sweden, due to Cesium 137 contamination.  The reindeers eat the lichens which has accumulated the radioactive particles.