How many bobwhite quail hunters do you imagine have swallowed a few pellets of shot over their lifetime? Has there ever been a documented case of any of us dying from it?
I doubt it.
I doubt it, too. Maybe because we don't have gizzards that retain indigestable objects for an extended period of time. I'm extremely skeptical of most of these studies also, but your comparison isn't valid, Jim. Shot doesn't stay in our digestive tract long enough to harm us.
A better question, IMO, is: How about all the people who have been shot with lead shot early in their lives and they were never removed? These people ever shown signs of lead poisoning?