Toxicity Of Chromium Contaminated In Urban Soil And Phytoremediation

Soil is in the surface of terrestrial ecosystem, it is an indispensable part for the growth of plants. Soil quality could decide the growth status and impact human health in various forms. At present, city soil have been suffering serious pollution, the pollution had a great damage to the ecological environment, it will not only lead to air pollution to the city, but also cause the pollution of groundwater, harmed the health of local residents. In addition, the contaminant of city soil, affected not only the ecological function of soil, also can cause irreparable harm to the respiration. But in recent years, the heavy metal contaminated soil had been increasing in the world, people paid more and more attention to the pollution problems and how to control the pollution. Therefore, the research on soil heavy metals determination was imminent, but some related research results showed, the assessment of soil heavy metals on the bioavailability not only depended on the amount, but also with other related factors. So it is necessary to combine the total soil heavy metal and bio-available.In this paper, contaminated soil which was from chromium slag pile site in a factory of Hangzhou, we analyzed the chromium toxicity and the related factors of the contaminated soil, and used two methods, which were chemical extraction repair and woody plants seedling potted repair, by researching chromium biological effectiveness in soil-plants system, we tried to reflected the soil pollution levels and how it damage the woody plants, and provided the theory basis for the restoration and treatment of chrome pollution and ecological.According to the previous research and relevant experiences, we chose pollution chromium soil as the research object, and woody plants as the repair plant, to study on the phytoremediation of Cr polluted soil, toxicity and effectiveness, aim to discuss whether we can use greening tree species as the renovation plants to ease Cr contaminated soil.(1) The method of. compared with using the citric acid and industrial soda(Na2C3O) to remove six valence chromium of brown-field soils, we use a series of batch washing experiments and the extraction that use reagent only. Also, a three-step eluting method which combined the ratio of soil and water and the numbers of washing, and other index. as initial pH and time gradient, to find out the best method of washing,to provide the basis for the chemical remediation technology of the soil which contaminated by chromium slag.(2) By hydroponic experiment, we compared Cr6+stress on pinus massoniana seed germination in different concentration (2.5-20mg/L).Soil experimental study on the Inhibition to pinus massoniana sprout and roots in different proportion of chrome pollution soil. In addition. We analyzed the relations of the concentration of Cr and various forms of concentration in the soil with Cinnamonum camphora Seedlings that after different treatments. We also studied on distribution of different speciation of Cr to link the chemical remediation and phytoremediation. The Speciation of Cr in soil is ranked from high to low as residual, oxides, organics, carbonates, soluble, and exchangeable, and the Proportion in turn was47.2%,28.65%,8.55%,8.4%,7.05%, and1.15%. Using multiple linear regression on the speciation of Cr in soil, it shows that:the pH among the data of soil chemical properties, organic matter and cation exchange capacity were significant influence Cr speciation in soil, while the impact organic matter is not great.