Monday, March 21, 2011

Your Spouse is Radioactive: Radiation Risk in Perspective

Randall Munroe of XKCD has published an awesome visualization of radiation levels from various sources - view it here. Some points of interest:
  • People are radioactive: sleeping next to someone exposes you to 0.05 microsieverts, or 1/20th the dose you'd receive from an arm x-ray, thanks to trace amounts of radioactive isotopes we have in our bones and bodies - things like potassium-40 and carbon-14.

  • Bananas are surprisingly radioactive (thanks to all their potassium, a vital nutrient that also contains radioactive isotopes). Eating one single banana exposes you to a higher dose than living within 50 miles of a nuclear power plant for a year.

  • Coal power plants hit us with more radiation than nuclear plants do. This is because coal contains uranium and thorium, elements which are condensed and concentrated during the coal-burning process. And while nuclear waste is carefully confined, radioactive coal emissions go up the smokestacks and into our lungs, our cropland, and our fisheries. Living 50 miles from a coal plant will dose you with 0.3 microsieverts every year - that's like eating three bananas, for Christ's sake!

  • The Three Mile Island meltdown produced doses of up to 1 millisievert - about 1/6th the dose you'd receive from a chest CT scan. The Fukashima meltdown in Japan is producing doses of roughly 3.6 millisieverts per day at some sites within 50 km of the plant.

  • The lowest one-year dose clearly linked to increased cancer risk is 100 millisieverts. That would be equivalent to eating 2 million bananas, or spending a month in the neighborhood of the damaged Fukashima reactors. So avoid doing those things, and you should be fine.
I was also tickled to note that Munroe's chart was produced in association with "Ellen," the senior reactor operator at the Reed College Research Reactor. I spent a few months of my freshman year training (unsuccessfully) to become an NRC-licensed reactor operator, and even though I didn't follow through with it, I did learn a lot of excellent trivia about subatomic particles, nuclear history, and chemistry, which has been good material for party conversations these last few days.

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