Hey Y'all, we aren't in worry mode in Hawaii, we are in preparation mode.
I am putting think link into the permanent Fukushima page here
http://oahutrading.blogspot.com/p/japan-nuclear-information.html
Link is Cesium and Animals
http://markforeman.wordpress.com/2011/04/13/a-tale-of-two-cows/
Bottom line biological half life of 70 days, and Cesium can be excreted...however, can do plenty damage until then, it sits mostly in your muscles.
Prussian Blue, aka Radiogardase, is effective at removing Cesiuim and Thalium from your body. They say it doesn't have bad side effects, except maybe constipation. The CDC stocks it for event of emergency.
Here is government page that describes it. Apparently you need a prescription to buy it, which seems odd given that there are no bad side effects. Very odd. Watch out too!! It is an originally was a dye for the Prussian army uniform, and continues to be used as a dye. I expect plenty scammers to be selling stuff that may not protect you.
http://www.remm.nlm.gov/prussianblue.htm#how