One perspective that might be factored into this discussion is "Validity of the Linear No-Threshold Theory of Radiation Carcinogenesis at Low Doses"

http://www.world-nuclear.org/sym/1998/cohen.htm

I handled depleted uranium shells over thirty years ago with my bare hands. There were no ill effects. In my house I have a rock wall composed of White Rocky Mountain Crystal. Like granite, the rocks contain small amounts of radioactive material. The radiation emitted is measurable using a Geiger counter. The rocks generate a small amount of radon. My house is a well sealed house. The rock wall has been in place for over 25 years. I have observed no ill effects for myself or my family. But also during this time period I have witnessed several individuals who smoke and come down with cancer and they continue to smoke even after they undergo surgery and radiation therapy. I think there is sufficient evident that low levels of radiation may not be as harmful as some individuals have made it out to be.