Stabilization and Ecological Risk Evaluation of Heavy Metals in Farmland Soils by Addition of Attapulgite Modified with Phosphates

Purpose. Attapulgite was modified by sodium dihydrogen phosphate, oxalic acid-activated phosphate rock powder, potassium calcium superphosphate, ammonium and fused calcium-magnesium used in the remediation of Cd, Zn, Ni. Materials Methods. six kinds (ratio: 1 : 2), improvement effect passivation material on soil polluted cadmium, zinc, nickel determined. CaCl2-extractable toxicity characteristic leaching procedure- (TCLP-) extractable Ni were measured order to estimate bioavailability stabilization efficiency. Pot experiment conducted study enrichment transport ability corn. The ecological risk environment evaluated calculating SEm, ERIm, CRIm, BUF. Results Discussion. Compared with ATP, materials AAPR, AMRP, ASSP, AMAP, AFMP can improve stability CD, soil, AAPR has best effect. CK treatments ATP treatments, concentrations TCLP-extractable Cd decreased 30.80% 24.72%, respectively, Zn 15.50% 11.18%, 31.34% 23.20%, respectively. CRI, BUF-Cd, BUF-Ni, BUF-Zn 24.67%, 52.88%, 78.73%, 41.18%, treatments. Conclusions. Phosphate-modified attapulgite effectively heavy metals reduce migration metals. In Ni, is best. Therefore, be as an economical, safe, effective Cd-, Zn-, Ni-contaminated which would have a high utilization value field applications.