Timsup2nothin
Deity
- Joined
- Apr 2, 2013
- Messages
- 46,737
Often the byproducts of radioactive decay are highly toxic all on their own, regardless of whether they are radioactive.
Well, radioactive materials tend to be isotopes of fairly rare elements, and biological systems develop based on using common elements. Animals breath oxygen...any evolutionary paths leading towards breathing Xenon suffocated themselves. (I know, Xenon is an inert gas so has basically no utility in bio-chemistry, but it was the first extreme scarcity gas I could think of. Anyway...) So, since biological systems seldom encountered these rare elements no adaptation for using them, or even living with them, has occurred. Yes, they are often highly toxic.
But being radioactive is a severe problem all on it's own. The O-15 example is a good one, since we know that Nitrogen is harmless. Nitrogen is everywhere. But if you take a typical water molecule just bopping along and all of a sudden the oxygen atom turns into nitrogen you have an aminyl radical instead of a water molecule. Aminyl radicals aren't found in nature at all because even though they are an intermediate step in all kinds of reactions they are so chemically active that the only way you could keep one around is if it is by itself in a vacuum. Form one in your bloodstream and it will immediately do something chemically to whatever happens to be around.