Bradlee
Enlightened
How long does tritiated water reside in the body and how many grams of inhaled tritium would it take to do as much damage as say a common medical xray.
From this article: "Tritiated water is taken up readily by cells and is eliminated over an extended period with a biological half-life in humans of about 10 days (I), producing a chronic radiation exposure."
With regards to your latter question, what I got out of the HPA article sited above is that scientists don't agree on the relative biological effectiveness of beta particles relative to x-rays (though the consensus seems to be that it's higher), so it's hard to calculate an accurate figure.