I recently ran into this old article while looking for a new study that showed small doses of radiation help cells to modify themselves to tolerate much larger doses of radiation, --doses that would damage/kill/cause cancer in cells that had never been exposed to any radiation. Makes sense, most living things will build up a resistance to any toxic substance, if it is given in very low doses. And most toxic substances are beneficial in small amounts.
I never heard about this immune system stimulation study before.--It is interesting. I remember all the environmental fanatics that were asking for zero (insert your chemical here) in municipal water supplies. Even though the purest water on the planet has more than that, and even though studies show some is beneficial.
Selenium for instance. It causes birth defects in high amounts, so the environmentalists want ZERO in the water. What the idiots don't realize though, is that when levels are too low, that also causes birth defects. It is even added to animal feeds to decrease birth defects and improve health. I see the same thing happening all the time. Environmental groups keep pushing for lower and lower percentages of anything man made, and they ignore what normal levels shold be for maximum health. (Though, technically, nothing is really man made.--just concentrated or refined.)
This goes back to the zero tolerance nonsense that so many environmentalists believe in.
Remember bottled mineral water? It was said to increase health and energy levels of those who drank it because the water came from springs rich in minerals (uranium), and the small amount of radiation in it was supposed to give you energy. Imagine EVIAN or PERRIER advertising that today! The brainwashed consumers of today would run screaming if they even saw a bottle of it! 
Then there is todays bottled water. It isn't regulated, and when the water is analyzed, the levels of chemicals are measured to be far higher, of virtually every kind, than municipal water anywhere in the country. And people are willing to pay more for this "dirty" water than they are for gasoline?---People are nuts!
Rodney
