Inducing Effect Of Accumulation Ability Of Heavy Metal By Plant In Contaminated Soil

Recently, phytoextraction theory and application has become a focus in environmental scientific area. In this paper, the plant effect and soil chemical behavior under inducement, including adding EDTA, citric acid waste water, monosodium glutamate waster water and wood fungi contagion was studied by pot experiment, heavy metal activity was evaluated with a cation exchange batch procedure, and the plant availability of heavy metal forms was evaluated with partial dissolution procedure and stimulated Cu forms.Study of the effect of inducement on absorb and transfer of heavy metals by plant showed that, the amout of Cu and Zn absorbed by plant was increased evidently by adding EDTA, as Zn and Cd were concerned, similar phenomenon presented when adding monosodium glutamated waste water or wood fungi contagion. Besides, except citric acid waste water, addition promoted the transference of heavy metals from root to shoot in plant.The chemical behavior of paddy soil was difference between with rhizosphere and non-rhizosphere under inducement. The pH value of rhizosphere was reduced by inducement, especially adding monosodium glutamate waster water. The phenomenon that heavy metal concentration in rhizosphere was higher than that of non-rhizosphere showed that, the activation rate was greater than the rate of plant absorbing and matter passing from non-rhizosphere. The most evident effect of addition on chemical behavior of Cu and Zn was EDTA, followed with monosodium glutamate waste water and citric acid waste water. In addition, microbe biomass in rhizosphere under inducement was higher than that of non-rhizospher, which resulted in increasing of DOC concentration in rhizosphere.The solubility sequence of heavy metals in Fuyan paddy soil was Zn>Pb>Cu, it was changed to Zn>Cu>Pb effected by organic complexing agent. Similarly, the solubility sequence of heavy metals in Qingzi soil was Zn> Cu>Pb, it was changed to Cu>Zn>Pb effected by organic complexing agent. The change of soluble and ionic heavy metal concentration in soil solution showed that, the activity and plant availability of heavy metals was higher than that of the check.The existing forms of heavy metal in soils were greatly changed by root and inducement. The amount of CaCI2 extractable heavy metal was increased elfected by inducement. As the transform of Cu was concerned, the Cu bounded to carbonate and organic matter bound Cu wasstrongly activated by inducement , so them were easily absorbed by plant compared with others forms. The Fe/Mn oxide bound Cu and residual Cu were poorly available, they could slightly transformed to other forms induced by EDTA and monosodium glutamate waster water.Study of availability of various Cu fractions in soil-plant system and its inducing effect showed that, the sequence of availability of Cu forms to plant is soluble plus exchangeable Cu and organic matter bound Cu > Cu bounded to carbonate > Fe/Mn oxide bound Cu > residual Cu. Effect of EDTA on dissolving of Cu from soil and absorb and transfer of plant was greater than that of monosodium glutamate waste water and citric acid waste water.