Leaching and uptake of heavy metals by ten different species of plants during an EDTA-assisted phytoextraction process

In a pot experiment, the potential use of 10 plant species, including six dicotyledon species and four monocotyledon species, was investigated for the EDTA-enhanced phytoextraction of Pb from contaminated soil. Mung bean and buckwheat had a higher sensitivity to the EDTA treatment in soils. In the 2.5 and 5.0 mmol kg(-1) EDTA treatments, the Pb concentrations in the shoots of the six dicotyledon species ranged from 1,000 to 3,000 mg kg(-1) of dry matter, which were higher than those of the monocotyledon species. The highest amount of phytoextracted Pb (2.9 mg Pb pot(-1)) was achieved in sunflowers, due to the high concentration of Pb in their shoots and large biomass, followed by corns (1.8 mg Pb pot(-1)) and peas (1.1 mg Pb pot(-1)). The leaching behavior of heavy metals as a result of applying EDTA to the surface of the soil was also investigated using short soil-leaching columns (9.0-cm diameter, 20-cm height) by the percolation of artificial rainfall. About 3.5%, 15.8%, 13.7% and 20.6% of soil Pb, Cu, Zn and Cd, respectively, were leached from the soil columns after the application of 5.0 mmol kg(-1) of EDTA. The growth of sunflowers in the soil columns had little effect on the amount of metals that were leached out. This was probably due to the shallowness of the layer of soil, the short time-span of the uptake of metals by the plant and the plant's simple root systems.     

Diagnosis and recommendations for transjurisdictional water pollution management in China

Large-scale water environmental deterioration is one of the most prominent environmental issues in current China. Transjurisdictional water pollution is an important reason for water environmental deterioration of river basins, and currently there are some major defects that exist in China's management system related to transjurisdictional water pollution. With seven major river basins in China as an object of study, this paper is designed to perform a diagnosis of major problems about the transjurisdictional water pollution management in China from three aspects, i.e. institution, mechanism, and legislation. On the basis of this, it gives an overall train of thoughts on the reform of transjurisdictional water pollution management in China, and proposes specific recommendations from the aforesaid three aspects.     

Degradation of 4-aminophenol by hydrogen peroxide oxidation using enzyme from Serratia marcescens as catalyst

This paper reports on the degradation of 4-aminophenol using hydrogen peroxide as oxidizer and the enzyme from Serratia marcescens AB 90027 as catalyst. The effecting factors during degradation and the degrading mechanism were studied. Also, the location of the enzyme in the cell, which could catalyze the degradation of 4-aminophenol, was analyzed. The results showed that to degrade 50 mL of 4-aminophenol whose concentration was 500 mg/L, the optimal conditions were: volume of H₂O₂ = 3 mL, temperature = 40–60°C and pH = 9–10. In the degradation process, 4-aminophenol was first converted to benzoquinone and NH₃, then organic acids including maleic acid, fumaleic acid, and oxalic acid were formed, and then finally CO₂ and H₂O were generated as final products. The enzyme that could catalyze the degradation of 4-aminophenol was mainly extracellular enzyme.     

21世纪前5年我国可持续发展战略的取向

“十五”期间,可持续发展战略仍将是我国最重要的发展战略之一。本文提出了“十五”计划和2010年规划可持续发展战略的目标和政策建议。     

西部开发应坚持可持续发展战略

本文分析了西部地生态环境问题产生的原因,提出了西部生态环境建设的总体思路和战略设想,进一步指出西部不同地区要因地制宜,采取不同的生态环境经济策略,才能在大开发中,实现可持续发展。     

高压M废水生化处理中硫化物测定方法的探讨

高压Ｍ废水成分较复杂，如何准确测定其中硫化物的含量，是考查高压Ｍ废水处理好坏的关键问题．本论文分析了测量误差产生的原因，选择了能使测量值趋于准确的新型预处理沉淀剂，并根据水中硫化物含量的不同，选用不同的测量方法，达到减少杂质干扰、准确分析、降低误差的目的．     

Phytostabilization potential of evening primrose (Oenothera glazioviana) for copper-contaminated sites

A field investigation, field experiment, and hydroponic experiment were conducted to evaluate feasibility of using Oenothera glazioviana for phytostabilization of copper-contaminated soil. In semiarid mine tailings in Tongling, Anhui, China, O. glazioviana, a copper excluder, was a dominant species in the community, with a low bioaccumulation factor, the lowest copper translocation factor, and the lowest copper content in seed (8 mg kg^?1). When O. glazioviana was planted in copper-polluted farmland soil in Nanjing, Jiangsu, China, its growth and development improved and the level of γ-linolenic acid in seeds reached 17.1 %, compared with 8.73 % in mine tailings. A hydroponic study showed that O. glazioviana had high tolerance to copper, low upward transportation capacity of copper, and a high γ-linolenic acid content. Therefore, it has great potential for the phytostabilization of copper-contaminated soils and a high commercial value without risk to human health.     

Anaerobic oxidation of arsenite by bioreduced nontronite

The redox state of arsenic controls its toxicity and mobility in the subsurface environment. Understanding the redox reactions of arsenic is particularly important for addressing its environmental behavior. Clay minerals are commonly found in soils and sediments, which are an important host for arsenic. However, limited information is known about the redox reactions between arsenic and structural Fe in clay minerals. In this study, the redox reactions between As(III)/As(V) and structural Fe in nontronite NAu-2 were investigated in anaerobic batch experiments. No oxidation of As(III) was observed by the native Fe(III)-NAu-2. Interestingly, anaerobic oxidation of As(III) to As(V) occurred after Fe(III)-NAu-2 was bioreduced. Furthermore, anaerobic oxidization of As(III) by bioreduced NAu-2 was significantly promoted by increasing Fe(III)-NAu-2 reduction extent and initial As(III) concentrations. Bioreduction of Fe(III)-NAu-2 generated reactive Fe(III)-O-Fe(II) moieties at clay mineral edge sites. Anaerobic oxidation of As(III) was attributed to the strong oxidation activity of the structural Fe(III) within the Fe(III)-O-Fe(II) moieties. Our results provide a potential explanation for the presence of As(V) in the anaerobic subsurface environment. Our findings also highlight that clay minerals can play an important role in controlling the redox state of arsenic in the natural environment.     

中国绿色服务政策演进、协同及文本内容分析

绿色服务作为促进绿色产业专业化、高端化、规范化发展的综合性服务业,是保障绿色产业持续健康发展的重要支撑。本文以《绿色产业指导目录》为依据,全面梳理1986年以来我国中央政府颁布的各类绿色服务政策,从政策演进、政策主体关系、文本类型、政策工具结构等方面对我国绿色服务政策进行量化分析。研究发现:(1)我国中央政府颁布的绿色服务政策数量及总力度都越来越大,绿色服务政策的制定已经渡过探索期,进入高质量发展的政策体系全面形成阶段;(2)政策主体牵涉广泛,部际合作现象明显且合作模式较为固定,整体上部际合作增强但又呈现出阶段性的发展特征;(3)政策类型多种多样,但不同形式的政策文件分布不均,多通知、公告类低效力文件,缺乏高效力文件;(4)政策客体结构较为完整,但行业分布不平衡;(5)总体上政策工具类型逐渐多样化,但过度重视管理,供给型、环境型、需求型三大政策工具间存在一定程度的失衡,具体表现为重环境,轻供给和需求。本文建议,应进一步加强部际协调和有效合作,平衡政策工具结构和政策的行业分布,完成绿色服务政策由量到质的升级发展。     

4种茄科植物对矿区污染土壤重金属的吸收和富集

采集了湖南及江苏8个矿区或冶炼厂周边4种茄科(Solanaceae)植物及其根际土壤,分析了植物及土壤样品中Cd、Cu、Pb、Mn和Zn 5种重金属浓度.结果表明:番茄(Lycopersicon esculentum)对5种重金属可能有着较强的耐性,但不具有超积累的潜力;刺天茄(Solanum indicum)对Mn、...