Influence Of Activated Materials On Improving The Accumulation Ability Of Pteris Vittata L.

In recent year, As hyperaccumulator Pteris vittata L., is successfully applied for remediating farmland contaminated soil in south mining area of China. And it showed great potential to remediate multi-metals contaminated soil. Base on the research status of remediation technology for multi-metals and As contaminated soils, this study would be divided into two parts:(1) We collected the Fluvo-aquic soil and Brown soil, the laboratory incubation experiments and pot experiments were conducted to research the influence of different activation materials to effectiveness and transformation of As, Pb, and Cd in soil, the influence of each parts of Pteris vittata L to absorb As, Pb, and Cd. (2) Took steel work site as example, the field experiments were research the effect of different types of fertilizer to absorbing As in each growing stage of Pteris vittata L., which can provide scientific basis for selecting appropriate phosphate fertilizer type for phytoremediation. The main results are as follows:(1) Application of activated materials increased the available As, Pb, and Cd in soil made them more absorbable. Monoammonium phosphatet(NH4H2PO4) showed better ability of As release, while the ethylenediaminetetraacetia acid(EDTA) showed better ability of Pb, Cd release.(2) Application of EDTA increased the fraction of exchangeable and carbonate form of Pb, Cd, while the Fe/Mn oxide and organic combination decreased, and the residual form have no significant change. These means that application of EDTA made the stable states of Pb, Cd transformed into bioavailable.(3) Adding the NH4H2PO4,citric acid significantly promoted the growth and development of Pteris vittata L. While adding EDTA was just the opposite. NH4H2PO4, citric acid could significantly increase As uptake of Pteris vittata L. Adding EDTA could increased Pb, Cd uptake of Pteris vittata L., there was obviously different with other treatments.(4) In this study, the transport capacity of As in the leaf/stem was higher than stem/root. The transport capacity of the Pb, Cd in the stem/root was higher than leaf/stem. Adding NH4H2PO4, citric acid improved the ability of the absorption of As from root move to aboveground. While adding EDTA improved the ability of the absorption of Pb, Cd from root move to aboveground.(5) Under the NH4H2PO4 treatment, the content of soil available As was significantly higher than other treatments. The EDTA treatment had the highest content of soil available Pb, Cd. After planting, the content of available metals in soil were decreased. Adding EDTA promoted the stable states of Pb, Cd transformed into bioavailable. It was conductive to improve phytoremediation efficiency.(6) In field experiments, application of phosphate fertilizer promoted the growth and increased As uptake of Pteris vittata L. As time went on, the biomass ofPteris vittata L. trend to increase steady. After 6 month of the experiment, the aboveground content of As reached the maximum. The efficiency would be best by supplied with NH4H2PO4, and supplied with KH2PO4 was better than Ca(H2PO4)2. Therefore supplied with NH4H2PO4 could significantly enhance efficiency of phytoremediation by Pteris vittata L. in As contaminated soil.