As mentioned above Lawry targets are politcally correct. Like politicians, pigs will eat anything for their survival
As for plastic wads, my farm sporting clays range never has a plastic wad or a plastic hull that remains for over a year. The microtines ( mice et al) love to chew this plastic with its salts to nothing. All that is left is an oxidizing brass piece of brass metal.
A lot of shotshell lead has also been dumped by my well that is surface water fed. I have an inorgnic analysis of my water made every summer and fall. The result is no heavy metal content for the past twenty years.
As for bio-magnification of toxins in the raptor population from eating the microtines,the raptor population seems to have increased over the years. The increase raptor population assertion appears to have been supported by studies by government biologists.