ARS | Publication request: Biochar-attenuated desorption of heavy metals in small arms range soils

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: January 2, 2013
Publication Date: N/A

Technical Abstract: Stabilization (capping/solidification) and dilution (e.g., washing, chelate-assisted phytoremediation) represent non-removal and removal remediation technologies for heavy metal contaminated soils. Biochar is stable in soil, and contains carboxyl and other surface ligands; these properties are useful for stabilization and dilution. Our previous TCLP extraction studies indicated that heavy metals in biochar amended small arms range soils (SARs) were resistant to desorption, compared to model systems where metals were added to agricultural soils. However, subsequent gastric phase extraction resulted in nearly 100% bioaccessibility in all cases. This study aimed to separately investigate the influence of pH and complexation on metal desorption from biochar-amended SARs having diverse pH (4.4-8.2), CEC (0.95-28.62 cmolc kg-1), TOC (0.5-31.6%), and Pb (5,000-20,000 mg g-1). Sequential extraction was conducted with and without buffer, EDTA, and gastrointestinal phases. Multivariate receptor model was used to quantitatively determine the factors responsible for the biochar's ability to bind or release heavy metals.