It's not the dropping dead from eating; it's the developing who-knows-what over time and then dropping dead.

I have read there are studies of small mammals and of roe deer in Europe that have found elevated levels of mercury, and in the U.S. the mammals that eat from marine-based foodchains (killer whales and polar bears, for example) have also been found with elevated mercury that is suspected as a cause of reproductive problems and death. Wasn't there a ban on lead shot in part because of environmental contamination that was finding its way into waterfowl?

My question is just, does anybody know where this stuff is likely to be less of a problem?

Guarantees I do not expect but, yes, I would love it if some responsible expert published a study saying the animals in this part of the US were tested and found to have a low incidence of various pollutants in their systems. Wouldn't you?