I have this complete study somewhere and it may easily be found. A few years back while trying to establish a public trap/skeet range, the "hunters" opposed to it came out and cited the dangers from all the lead that would be deposited at the site, even though they had been presented the report. I finally gave up.
The lead bullets from Civil War battlefields, millions still in the ground, all exhibit the white coating that seals the soluable lead. So do all the lead pellets ever shot, over time.
http://www.sciencedaily.com/releases...1129074745.htm
http://www.vtnews.vt.edu/articles/2004/11/2004-529.html