Thank you for the insight. I completely forgot about the biological half life. I thought ‘uptake’ isotopes like Strongtium would not be eliminated from the body well. Strontium to the bones - cesium to the muscle etc. So is there a rule of thumb how much the body eliminates - ie is it really half or in general half? Thanks in advance.
The biological half life has nothing to do with radioactivity, and is specific to the element.
You can get a good idea how an element will behave in the body by looking at a periodic chart and finding element in the same period. For instance cesium is in the same period as potassium and sodium so it will behave similarly. Likewise, strontium is in the same period as calcium and iodine is in the same period as chlorine.
Every healthy body eliminates these elements pretty much at the same rate, so the biological half life is close for most people.
I mention iodine and cesium specifically because I-131, Cs-134, and Cs-137 were found in the environment outside of the reactor plants.