Lead from shooting comes from range cleanup, dust particles in the air get inhaled. Few other sources of lead contanmination
Vehicles, old paint, car paint (yes still uses lead in automobile paint), any type of lead processing, i.e. casting, battery companies etc..
Sweeping indoor ranges produce lead dust, casting bullets produce lead fumes that will linger for many hours.
Few other facts, kids pose the greatest risk of lead exposure. They absorb lead in the body much faster and a greater % than any adult can which makes it the greatest risk of all. 10% in adults and 50% in children. Lead absorption is enhanced if diet is poor in iron or calcium.