I cannot tell you what this means- I am far from a chemist... but it doesn't look good. The best we can say is that we're not yet sure how the radiation from the nuclear plant in Japan is going to effect the world as we know it. And that isn't saying much.
http://www.zerohedge.com/article/xenon-133-dispersion-animation-radionuclide-has-blanketed-entire-united-states
RADIOACTIVE RAIN in Japan-
http://www.zerohedge.com/article/nhk-finally-confirms-fuel-damage-radioactive-rain-starts-pour-and-japan-increases-decontamin
I have a really difficult time thinking about the next 20, 50, 100 years in relation to this extreme radiation. There is going to be so very much suffering.