New alternatives in the management of metals (e.g., cadmium, chromium, lead, zinc, etc.) and metalloids (e.g. arsenic, selenium) can provide significant cost savings when implemented on a contaminated site. By creating site-specific treatments, metals-contaminated materials are increasingly allowed to be reused on-site or left in-place. These treatment options create environmentally-stable compounds that reduce soil handling and disposal costs, increase flexibility in site development and design, and create alternatives to recycle and reuse materials on-site. In many cases, risk-based remediation goals can be developed for a site to achieve an appropriate goal for the intended land use and surrounding environment.

Site-specific treatment chemistries are combined with increasingly flexible remediation goal(s) and land use considerations. In at least 11 states within four USEPA regions, treated materials has been approved for on-site reuse by demonstrating the reduction of metals leaching in soil and groundwater using both the Toxicity Characteristic Leaching Procedure (TCLP) and Synthetic Precipitation Leaching Procedure (SPLP) tests. In some cases, on-site groundwater can be used as a substitute to the leaching fluid in these procedures to demonstrate site-specific metals stability with respect to leaching. In the near future the use of physiologically-based extraction tests may expand remediation alternatives to address bioavailability reductions ( June 2005 Remediation Trends Newsletter (57.05 KB)) through stabilization treatments.

Example approaches

• Chemical stabilization reagents
  • Phosphate blends
  • Sulfide blends
  • Iron blends
  • pH control
  • Custom blends
• In situ treatment with excavation and disposal or on-site reuse
• Ex situ treatment with excavation and disposal or on-site reuse
• Natural attenuation for the management of residuals and downgradient plumes

Example sites

• Foundries
• Plating operations
• Inorganic fertilizer/pesticide manufacturing, formulation and application sites
• Battery manufacturing and disposal sites
• Waste disposal sites