Effects Of Amendment Treatments And Elsholtzia Splendens On The Combined Contamination Of Copper And Cadmium In Red Soil

At present, the problem of soil heavy metal pollution, especially combined pollution of heavy metals, was very serious. Cu, Cd, while not associated heavy metals, but the actual monitoring results showed that the soil often exist in copper and cadmium pollution, and little of cadmium,excessive levels of Cu are toxic to plants will be. Of Cu, Cd combined pollution and the use of Hyperaccumulator + conditioner repair technique to repair the joint copper, cadmium compound contamination in red has a certain theoretical significance.The effect of heavy metal hyperaccumulating plant, Elsholtzia splendens. And chemically amendments on Cu-Cd contaminated red soil was studied by plant pot and seed germination experiments in this paper. The chemically amendment include the titanium dioxide and chitosan. Heavy metals content in plant and soils, trait index (biomass, chlorophyll, SOD, POD, MDA) in roots, stems and leaves of plant, and soil enzyme were analyzed to demonstrate the effect of the amendments.The major findings were as follows:1. The seed germination experimental results showed that: The seed germination rate first rose and then dropped which increased with the concentration of Cu2+ ,and the maximum seed germination rate appeared in the 20mg/L Cu2+ concentration. However, the prolongation of root and the seedling heights were restrained obviously under the copper and cadmium stress or CCu2+≥40mg/L. According to the combined effect of indicators, there was synergy between copper and cadmium under compound condition.2. The effect on different physiological and biochemical characteristics of Cu-Cd combined pollution and a single copper pollution:1) biomass, chlorophyll, root activity, anti-oxidation systems enzymes and MDA analysis shows that: composite copper and cadmium combined pollution of the red soil over a single copper pollution, a greater contribution to the growth of Elsholtzia splendens. Improved handling of different combined pollution of Cu and Cd, copper concentrations of less than 200mg/kg, the chitosan and titanium dioxide compound improved handling of the copper and cadmium in red soil pollution on the growth of Elsholtzia splendens better.2) Copper speciation and Elsholtzia splendens copper and cadmium accumulation analysis showed that: composite copper and cadmium pollution and a single copper pollution were the main iron-manganese oxide bound, followed by the carbonate-bound and organic matter-bound, exchangeable and the residue content of at least. Elsholtzia splendens accumulation of copper in the body, mainly in the roots, cadmium accumulation in the stems.3) The analysis showed that the activity of soil enzymes: copper and cadmium combined pollution can stimulate the combined pollution of soil protease, peroxidase, acid phosphatase and urease activity. Which the soil peroxidase, acid phosphatase could be used as non-amended handling, amended handling of titanium dioxide and chitosan of the copper and cadmium in red soil pollution, Cu and Cd key biochemical indicators of pollution levels.