As far as I know the EPA's hands are tied in regards to lead in ammo. That's the ONE thing that congress forbade that the EPA can do anything about.
It might be a good thing to check the Migratory Waterfowl Laws/Rules before your next duck hunt.
Here in Missouri the Missouri Department of Conservation has several of their hunting areas that are no lead zones. This even applies to turkey, dove, rabbit hunting lands that the MDC owns.