Study On Phytoremediation And Soil Improvement For Soil Polluted By Manganese Mine Tailings

The study on the soil enzyme activities in Phytolacca acinosa Roxb. rhizosphere and non-rhizosphere soil of Xiangtan manganese mine showed that all tested enzyme activities were higher in rhizosphere than in non-rhizosphere soil. The effects of rhizosphere environment on the soil enzyme activities were in the sequence of invertase > urease >dehydrogenase> acid phosphatase >catalase, and the R/S value was1.687, 1.598, 1.586, 1.485, 1.328, respectively. The tested enzyme activities were negatively correlated with soil heavy metals pollution except catalase activity, suggesting the inhibitory effects of heavy metals joint pollution on soil enzyme activities. Soil enzyme activities of rhizosphere and non-rhizosphere soil of Phragmites australis in Xiangtan manganese mine had also been studied. The effects of rhizosphere environment on the soil enzyme activities were in the sequence of invertase > dehydrogenase > catalase >acid phosphatase>urease, and the R/S value was 1.759, 1.485, 1.425, 1.406, 1.394, respectively. Both Phytolacca acinosa Roxb. and Phragmites australis could effectively improve soil environment, and thus, enhance the activities of soil enzymes. Both of the two kinds of plants were good candidates of Phytoremediation for manganese polluted soil.Manganese mine tailings were rich in heavy metal and had poor physical properties. The differences in the activity of SOD and accumulation of MAD in plant max seedling, production of plants, metal content, soil pH, morphology of soil metals etc. were studied through pot culture experiment which used low-grade polluted soil by manganese mine tailings, followed by adding different level of lime, calcium magnesium phosphate, mixture of lime and calcium magnesium phosphate respectively. The results showed that:(1) Heavy metal did great harm to plant and decreased the production of cabbage, however, adding lime, calcium magnesium phosphate, mixture of lime and calcium magnesium phosphate could increase the production significantly. The three additives could relief the toxicity to cabbage significantly.(2) The MDA content and the activity of SOD in the cabbage were increased under heavy metal stress. Adding lime, calcium magnesium phosphate, mixture of lime and calcium magnesium phosphate could decrease the MDA content and the activity of SOD in the body of plants. (3) The content of Mn, Cd, Pb adsorbed by plants was related positively to the content of available Mn, Cd, Pb in soils, and the latter was influenced by the soil pH. The available Mn, Cd, Pb decreased significantly after adding lime, calcium magnesium phosphate, mixture of lime and calcium magnesium phosphate to the soil, especially the available Mn.