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> Remediation requires completely replacing the top several feet of soil. I think the normal recommendation for backyards is several inches, not feet, of soil.

by wahern 5y ago

> Remediation requires completely replacing the top several feet of soil. I think the normal recommendation for backyards is several inches, not feet, of soil. But there's also an alternative: fish bones. They bind the lead so it can't be absorbed well even if ingested. You can buy them by the ton from PIMS NW, Inc: http://www.pimsnw.com/ http://www.pimsnw.com/ But you need to spread quite alot of fish bones. As cheap as they are, it's still not very cost effective, especially considering that, excepting extreme industrial contamination, lead-contaminated soil usually goes to a non-hazardous dump site or used for backfill, and rarely to a much more expensive hazardous dump. It's cheaper to haul the dirt away than to haul in tons of fish bones.

nate_meurer 5y ago
The more common chemical abatement technique is amendment with lime. Maybe fish bones are cheaper in some coastal locations, I don't know, but it's interesting. There's also some evidence that calcium supplements given concurrently with lead exposure could reduce the absorption into sensitive tissues (particularly brain and bones), but I don't know how strong the evidence is. EDIT: The depth of excavation is determined based on the expected use of the land, and how deep the contamination extends based on soil sampling. Anecdotally, I know that excavation of residential areas at the smelter superfund site in Pueblo (south of me) extended to two feet around the houses.