Heavy Metal Stabilization in Deep Agricultural Soils Using Sulfate-Reducing Bacteria

Abstract

Heavy metal stabilization in soil was investigated using sulfate-reducing bacteria (SRB). Samples were collected from three agricultural soils near abandoned mines, and a nine-week batch experiment was performed following the classification of soils as ① non-sterile soil with SO 4 2-(SO4), ② sterile soil with SRB (SRBo), and ③ non-sterile soil with SRB and SO 4 2-(SS). Heavy metals were extracted using 0.1 N HCl or Mehlich, and the stabilization efficiency was evaluated by comparing the results to the control. Pb, Zn, Cu, and Cd (4-55%) had higher stabilization efficiency than the control in Mehlich extraction, while Pb (2-41%) had higher stabilization efficiency than the control in 0.1 N HCl extraction. The SS samples demonstrated a high stabilization efficiency (17-55%), whereas the SRBo samples (2-37%) showed a low efficiency. Dissolved As decreased in the supernatant of the SO4 and SS samples, especially in the high-As soil. These results indicate that incorporating SRB and SO 4 2into soil contaminated with heavy metals can effectively decrease the mobility of As and heavy metals.