Impacts of Trace Elements Iron and Zinc on Phytoavailability of Heavy Metals Cadmium and Lead

In this paper, the soil simulation pot experiment was carried out to study the impacts of trace elements iron (Fe) and zinc (Zn) on availability of cadmium (Cd) and lead (Pb). The self-made Cd and Pb compound contaminated soil was taken as the test soil, and wheat was taken as the test plant. The results show that with the increase in Fe dosage, overground dry weight, root dry weight, and total dry weight of wheat gradually increase; the application of Zn reduces overground dry weight, root dry weight, and total dry weight of wheat. Meanwhile, wheat biomass under Cd and Pb combined pollution is smaller than that under single Cd pollution or single Pb pollution. The application of Fe fertilizer increases Cd absorption of various parts of wheat. In the single Cd pollution treatment, with the increase in Fe dosage, Cd concentrations in roots, stems and leaves of wheat will first be increased, then decreased; in Cd and Pb combined pollution treatment, with the increase in Fe, Cd concentrations in roots, stems and leaves of wheat will also be increased. The application of Fe promotes the Pb absorption of wheat. With the increase in Fe dosage, Pb concentrations in roots, stems and leaves of wheat will first be increased, then decreased slightly. Compared with Zn0, Cd concentrations of different parts of wheat after Zn1 and Zn2 treatment increase significantly. In addition, with the increase in Zn dosage, Cd concentrations of different parts of wheat will first increase, then decrease. Regardless of single Pb pollution treatment or Cd and Pb combined pollution treatment, Pb concentrations of different parts of wheat decrease as Zn dosage increases. Under different Fe and Zn levels, and when Cd and Pb coexist, Pb can promote Cd absorption of plant, but Cd inhibits Pb absorption of plant.