摘要：
In the paper, Authors separately used analytical hierarchy process, expert scoring method, principal component and BP network to establish the weights of ecological vulnerability evaluation Index system in the Hengyang Basin as a case, and used hierarchical-comprehensive index -clustering model, principal component-comprehensive index-clustering analysis model, expert scoring-composite index-clustering analysis model, BP artificial neural network model to evaluate separately the reality vulnerability in 2000. The results shows that study area are moderate weak, and the results broadly similar. Authors think that Principal component and artificial neural network model can avoid subjective factors, and taking the way of the expert group judgment is to reduce the error of ecological vulnerability assessment. With the impact of global change and the strengthening of fragile ecosystems, China has carried out many researches and practices on vulnerability assessments[1,14]. Although Vulnerability assessment in many ways, not yet formed a unified evaluation method, this paper draw on previous evaluation methods based on [1,11], using AHP, principal component analysis, BP neural network and expert scoring method on quantitative assessment and analysis, then clustering the results by comparison to determine which method to evaluate the most accurate. Authors analysis the Hengyang Basin reality vulnerability in 2000, attempting to explore a more suitable and easy erosion in hilly areas degraded fragile vulnerability assessment method. (C) 2011 Published by Elsevier Ltd. Selection and/or peer-review under responsibility of Conference ESIAT2011 Organization Committee.
作者机构：
[Zeng, Yongnian; 郑文武] Department of Surveying and Land Information Engineering, Central South University, South Lushan Road, Changsha 410083, China;[郑文武] Resources Environment and Tourism Management Department, Hengyang Normal University, 165 Huangbai Road, Hengyang 421008, China
通讯机构：
Department of Surveying and Land Information Engineering, Central South University, South Lushan Road, China
会议名称：
The International Symposium of Molecular Environmental Soil Science at the Interfaces in the Earth's Critical Zone(地球关键区界面反应：分子水平环境土壤科学国际会议)
会议时间：
2009-10-10
会议地点：
杭州
会议主办单位：
Zhejiang Univ
会议论文集名称：
The International Symposium of Molecular Environmental Soil Science at the Interfaces in the Earth's Critical Zone(地球关键区界面反应：分子水平环境土壤科学国际会议)论文集
摘要：
The inhibited or enhanced uptake of heavy metals by iron plaque has been observed. The relationship between amounts of adsorption and accumulation of heavy metals and iron plaque on roots of wetland plant is still unclear. This study examined the effects of iron plaque on lead (Pb) absorption and translocation between underground and above-ground parts of a wetland plant species. Broad-leaf cattail (Typha latifolia L.) was grown in soil for four weeks under waterlogged conditions in a greenhouse. The soils were treated by Pb as lead nitrate at four levels (0, 100, 500 and 1000 mg Pb·kg-1) and waterlogged for two weeks. The results showed that the amount of iron plaque in the treatment with addition of 500 mg Fe·kg-1 was general higher than that of the treatment with addition of 100 mg Fe·kg-1, Lead concentrations in both shoots and roots treated by 500 mg Fe·kg-1 was more than that of the treatment with 100 mg Fe·kg-1. When the ratio of added Fe and Pb was 1, the accumulation of Pb in plants was higher than that of other treatments at the same Pd level. Appropriate amount of iron supplied will benefit lead accumulation in plant, which help the removal or stabilization of lead in constructed wetland.
摘要：
Constructed wetlands have emerged as a viable option for helping to solve a wide range of water quality problems. However, heavy metals adsorbed by substrates would decrease the growth of plants, impair the functions of wetlands and eventually result in a failure of contaminant removal. Typha latifolia L., tolerant to heavy metals, has been widely used for phytoremediation of Pb/Zn mine tailings under waterlogged conditions. This study examined effects of iron as ferrous sulfate (100 and 500 mg/kg) and lead as lead nitrate (0, 100, 500 and 1000 mg/kg) on phosphorus utilization and microbial community structure in a constructed wetland. Wetland plants (T. latifolia) were grown for 8 weeks in rhizobags filled with a paddy soil under waterlogged conditions. The results showed that both the amount of iron plaque on the roots and phosphorus adsorbed on the plaque decreased with the amount of lead addition. When the ratio of added iron to lead was 1:1, phosphorus utilized by plants was the maximum. Total amount of phospholipids fatty acids (PLFAs) was 23%–59% higher in the rhizosphere soil than in bulk soil. The relative abundance of Gram-negative bacteria, aerobic bacteria, and methane oxidizing bacteria was also higher in the rhizosphere soil than in bulk soil, but opposite was observed for other bacteria and fungi. Based on cluster analysis, microbial communities were mostly controlled by the addition of ferrous sulfate and lead nitrate in rhizosphere and bulk soil, respectively.
