After remediation of residential properties in the Midwest, a large collection of lead-contaminated soil was accumulated in waste piles. There is a plan to use ~35,000 tonnes of this waste soil to help remediate a former lead smelting industrial site with lead concentrations up to 38,000 mg/kg. A layer of piled waste soil (60 cm) would cover the site, and a layer of clean soil (30 cm) would cover the piled soil to reduce individual's lead exposure. However, the threat of groundwater contamination would still be uncertain. Soil characterization and leaching tests (Sequential Extraction, Kinetic Batch Tests, Synthetic Precipitation Leaching Procedure, Toxicity Characteristic Leaching Procedure, Constant Acidity Leaching Protocol, and Acid Neutralization Capacity), along with the use of the Hydrus 1-D modeling program, were used to assess the risk of lead and arsenic migration into the underlying aquifer. It was found that the soil of the lead smelting site released hazardous (according to TCLP guidelines) amounts of lead (335 mg/L Pb) while all other layers were considered non-hazardous. However, the ANC demonstrated the resident soil's capability of retaining the leached concentrations of lead. Hydrus 1-D results helped to confirm this by showing slow metal movement (down to 1.2 m below the ground) and no aquifer penetration in the first millennium. Arsenic release was negligible in all soils. Therefore, it was concluded that the remediated soil may not pose a significant risk to the groundwater and the piled waste soil could be used for the site remediation generating significant savings.

Reuse of industrial lead-contaminated soil in urban applications

248th National Meeting (2014)

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