Vegetables: Do ALL take up radioactive elements?

Immediately after an airborne radioactive release, contamination coats the surface of plants, but over time that contamination moves into the soil and from there is taken up inside plants.

Which food sources concentrate radioactivity is fairly easily estimated by looking up the nutrients associated with those foods. For instance, cesium is mistaken for potassium, so foods with high potassium levels will concentrate radioactive cesium when grown in contaminated soil. Strontium and calcium behave similarly. Stable and radioactive iodine are indistinguishable from each other in chemical processes, so radioactive iodine will be taken up in the same percentage as it is present in the environment.

The physical half life of many radioactive contaminants is so long that we can assume they will be permanently with us for many generations. The biological half life is usually much shorter. So even after ingestion, switching to uncontaminated foods can, over time, decrease the levels in our bodies or those of our food animals. However, there seems to be a misunderstanding of biological half. AS LONG AS CONTAMINATED INTAKE CONTINUES, contamination will be present in plants and anything that eats them. There is an initial drop in levels as the radiation is distributed in the environment, but the rate of fall does not continue. Eventually plants, animals, and humans reach a steady state, where excretion of radioactive material matches uptake.

One thing I have gleaned from reading a *lot* of research papers on the Chernobyl accident aftermath is that soil remediation and animal feed supplementation with minerals can have a major impact on decreasing human ingestion of radioactive materials. However, it is expensive and may not be initiated or continued in for-profit food production. By extrapolation, I've decided I can probably decrease uptake by supplementing my diet directly. I wouldn't drink Prussian blue for Fukushima though.

http://www.bt.cdc.gov/radiation/prussianblue.asp

As long as there isn't another major airborne release, I think most of the danger here will come from imported food. Contamination is much higher in Japan, and governments aren't testing very much food. See this abstract for why knowing food sources is important:

http://www.ncbi.nlm.nih.gov/pubmed/20002056

Oh, and cabbage, garlic, onions, kale, broccoli, bok choy, and other members of the Brassicaceae family take up and concentrate radioactive materials through their roots. So if they're grown in contaminated soil, washing them off won't help.

Self-medication is STRONGLY cautioned against

I have had occasion to bury MDs who chose to self-medicate.

It is seldom advisable to ingest 'cures' that may be worse than the disease.

Prussian Blue is kinda nasty stuff, an industrial chemical that was once used in office copiers.

While useful for cyanide poisoning and some severe radiation emergencies, it is NOT an OTC kinda thing.