Did they do any soil testing around the area for lead? Other than in the berms? Or ground water testing? Just curious.
We did when we moved out of our old club. As long as the soil is fairly pH neutral, the lead(shot and/or bullets) just develops an oxidation layer around it, and becomes stable. It doesn't break down, or leech, or otherwise degrade. It just sits there, again, baring a highly acidic or alkaline soil.
The problem a club can run into (once it ceases operations or moves) is that the EPA standard for "clean" is a moving target. It all depends on what the land will be used for next. Housing development. Kids have to be able to eat the dirt, so you might as well haul it all away, and bring in clean. Shot usually only goes ~6 inches deep, if the ground is muddy, bullets go ~3 ft into a berm, max. IIRC. Never, ever, ever use tires as part of your backstop. Makes digging out the lead uneconomical and a cast iron bitch. Same with letting anything larger than grass or weeds grow in you shot fall areas. How do I know that. My club had both, making it uneconmical to recover lead at our former location (which is still for sale by the new owner, 9 years later...
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We had to do testing all around the property. Dirt samples (IIRC, somewhere around 20 from berms and 60 from the shot fall areas) all tested "OK" after the bullets and shot were screened out of the samples. In fact, IIRC, the numbers were the same for samples from the shooting and non-shooting parts of the club they sampled. The only area with any elevated levels of elemental lead contamination was along both side of the county road running next to the club.