As far as the environmental impact of a lead deer slug on the landscape, I can't believe it's anywhere near the negatives of the air pollution put out by millions of big rigs, cars and coal-fired power plants ( without stack scrubbing equipment ). I can see the likelihood of ducks, geese, pheasants, grouse and other birds picking up lead shot as they pick grit for aiding their digestion. One shotgun blast puts out dozens of shot X how many millions of shots nationwide. I saw the truckloads of lead shot hauled out of a local trap-shooting range when they had an excavation to re-coup the lead shot from the range. Astounding amount of lead. One deer slug here and there (if a pass-through) in the woods is minute in comparison.