Tandy, S., N. Meier, and R. Schulin.
Journal of Hazardous Materials 324(Pt B):617-625(2017)

Finding the right stabilization treatment for Pb and Sb in shooting range soils can be challenging because under oxidized conditions, Pb is a cation and Sb an anion, and they often show opposite mobility in soil upon application of amendments. A batch experiment was set up with two soils (slightly acidic and alkaline) and two red mud-based amendments (ViroSoil™ 1 and 2), alone and in combination with two reducing agents (zero-valent iron and iron sulfate), to assess the effect of the treatments on metal(loid) leaching and compare it to unamended soil and soil amended with goethite, a known Sb adsorbent. Fe sulfate was effective at reducing Sb leaching due to the reduction of Sb(V) to Sb(III), which bound more strongly to iron (hydr)oxides in soil, but Fe sulfate had an adverse effect on the leaching of Pb due to its acidifying effect and reductive Mn (hyd)roxides. Combining ViroSoil amendments with Fe sulfate reduced leaching by both Sb and Pb and proved a suitable in situ chemical stabilization treatment.