| Arsenic is a metalloid element widely distributed in nature, Its compounds are common harmful substances that can cause many diseases, even cancer. Arsenic in soil can not only enter the food chain threat to human health, but also into the air and water cause secondary pollution. Currently, the use of plant and microbial remediation of contaminated soil have become an increasing academic attention.In the laboratory and field repair of small-scale experiments have achieved some results.This industrial city on the industrial impact of typical soil survey, the initial reveal local soil pollution and its health threats. Both arsenic hyperaccumulator Pteris (Pteris vittata L.) and arsenic-reducing bacteria (F2-As, F2, C13) as materials, research and development under field conditions in the plant-microbial remediation of arsenic contaminated soil on-site remediation technologies, and Preparation of supporting microbial agents. The main results are as follows:1. Reveals a typical industrial city in southern China Hunan Chenzhou. smelting, pyroelectric. three mine-affected zone industrial Occurrence Characteristics of soil heavy metals and PAHs. the study found that three types of industries affected zone As the most common pollutants.2. Centipede grass developed for remediation of solid arsenic contaminated soil microbial agents, selected the best ratio of solid carrier:peat soil, sawdust, rice husk, activated carbon mass percentage:30:25～30:25～30:10～20of the most suitable for microbial growth. Adsorption of carrier agents to reach108-109/g. Agents can significantly improve the repair efficiency of centipede grass. Centipede grass imposed after the top agents biomass increased by16.8%. Centipede grass than the upper part of the absorption increased41.11%in control, centipede grass significantly increased the amount of absorption of arsenic3. In the field conditions. exogenous microbial agents to improve the centipede grass and arsenic concentration of bio-weight and improve the centipede grass above-and underground accumulation of arsenic, remediation efficiency of3.39%-6.66%. In addition to C13treatment, other treatment facilities in the centipede grass fungus Arsenic in the upper part of the cumulative volume was significantly higher than the control, the treatments F2-As the body deal with arsenic accumulation in Pteris vittata L. highest.308mg/m2, about1.59times the control And treatment with other agents with significant accumulation.4. In the field experiment, the foreign body micro-organisms can affect the centipede grass and soil arsenic speciation changes.90d, the agents can centipede grass treatment groups were upper As (Ⅲ) was increased to F2to increase the maximum is1.36times the control. Arsenic in the soil is still As (Ⅴ) mainly on the rhizosphere microorganisms in the soil As (Ⅲ) are promoted in the90d when compared with the control group, and other facilities bacteria group, agents can significantly F2-As Increase in rhizosphere As (Ⅲ) content is1.35times CK2. Exogenous microbial agents, each treatment group rhizosphere soil DOC content than the control group increased significantly, and among treatments were significant differences, of which the F2-As treatment group was the highest, the control group.2.78times, DOC Content increased bioavailability for arsenic in soil increases, the effective arsenic content than the control group increased6.01-23.20%, but not significantly. Content of arsenic is to increase the effective promotion of centipede grass is an important reason for the absorption.5. In the field experiment, using DGGE of exogenous microorganisms in the soil after the centipede grass diversity of microbial communities were analyzed. The results showed that:pre-applied arsenic reduction agents can increase the soil microbial community diversity and species richness,60days after the agents and the control exerted no difference. |
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