Effect of environmental materials on plant growth and immobilization of heavy metal lead and cadmium

Immobilization of heavy metal is an important way for restoration of the contaminated soil in situ so as to reduce the absorption amount of heavy metal by props. The pot method was used to explore the effect of environmental materials (humus material HA, polymer absorbent materials SAP, coal-derived composite material FM and salty mineral materials FS) on the plant (maize, soybean) growth and absorption to heavy metal of lead (Pb <= 150 mg/kg) and cadmium (Cd <= 10 mg/kg). The results showed that different environmental materials and their composites can markedly reduce the absorption amount of Pb, Cd by maize and soybean, and also promote growth of crops. Except a few treatments, the Pb, Cd content in maize shoot in most treatments decreases by 51%-71% and 66%-84% compared with that of control, in soybean shoot in all treatments decreases by 54%-76% and 33%-58% compared with that of control. Comparatively, SAP and the composites can reduce the absorption amount of heavy metal Pb, Cd in the soil of over 80% and 50%. Respectively, F2 (FS+HA+SAP) can be used as the renovation agent for restoration of heavy metal contaminated soil.