Natural Attenuation Remediation of Lead-Contaminated Soils at a Former Open Burning Propellant Disposal Site
Abstract
Lead-contaminated surface soils at an eleven-acre former open-burning propellant disposal site at the Badger Army Ammunition Plant were scheduled for remediation by phosphate-addition soil stabilization and soil cover construction. Laboratory treatability tests performed to select an effective mix of stabilization compounds suggested that native soils (a 5 - 7 foot thick loess deposit) underlying the contaminated topsoil had a high capacity to immobilize/attenuate lead naturally, without the addition of artificial chemical stabilizers. This initial testing showed that over 99% of dissolved lead content was removed from leachates contacted with the underlying soils, up to a leachate lead content of over 10,000 microgram/l. Before further studies were undertaken to support remediation through natural attenuation for this site, soil borings were installed on a 1001 grid to establish the presence of the attenuating loess layer across the entire site. Then, leachates created from contaminated site soils through the Synthetic Precipitation Leaching Procedure (SPLP) were contacted with underlying attenuating soil. Pre-contact and post-contact leachate lead concentrations were tracked to determine the level of attenuation achieved. The SPIP leachates, which characteristically had a low dissolved lead content, were also spiked with higher concentrations of lead (up to 10,000 microgram/l). Using these spiked leachates, the soils attenuation capacity at higher lead levels was evaluated. The results showed that the underlying soils had over 20,000 times more capacity to attenuate dissolved lead than the contaminated soils had capacity to generate dissolved lead. Securing approval from regulators to forego chemical stabilization/soil cover in favor of natural attenuation/soil cover was a rigorous process. Uke most military installations, remedial activities at Badger AAP are closely scrutinized by regulators and a local environmental group.
Document Details
- Document Type
- Technical Report
- Publication Date
- May 01, 1996
- Accession Number
- ADP017707
Entities
People
- Gretchen A. Haupt