We've been using lead for hundreds of years and everything ain't dead, done. Of course that's not good enough for the hippies but you shouldn't point out that "there's no creditable sciences to prove that...". Just say "in four hundred years we've not seen any threat that lead poses to the animal population, if we were finding dead critters with bullets in there guts, from eating them, all over the place WE would have noticed by now. Thank you for you concern for the environment, I too am a conservationist and share your concerns. And thankfully we've got nothing to worry about."
And you know what, maybe a couple of animals here and there eat lead left in kills, but I don't see no hippies trying to ban cars that killed the eight thousand dead deer a passed this morning. Hippies are just looking for something to feel good about, cause their life sucks.