EDTA对4种花卉富集Cd、Pb的效应

植物提取修复技术(Phytoremediation)是一种环境友好的重金属污染土壤原位修复技术,但是修复植物的提取效率经常受到目标金属的低植物有效性所限制。通过盆栽试验研究了乙二胺四乙酸(ethylenedi-aminetetraacetic acid,EDTA)对4种花卉富集Cd、Pb效应的影响。结果表明:施加EDTA溶液(3mmol/kg)7d后,矮牵牛、万寿菊、彩叶草叶部Cd含量显著增加(P<0.05);所选4种花卉叶部Pb的含量均极显著增高(p<0.01)。施加EDTA后万寿菊对Cd和孔雀草对Pb的富集系数和转移系数均达到了1以上,这表明这两种植物可用于螯合辅助植物提取方式的污染土壤修复。     

青萍在Pb、Cu污染水体植物修复中的应用研究

以青萍种浮萍（Lemna perpusilla Torr.）为实验材料,以Pb（Ⅱ）、Cu（Ⅱ）为染毒因子,设定金属离子浓度梯度（Pb（Ⅱ）：0～40 mg/L,Cu（Ⅱ）：0～4 mg/L）,考察了在不同金属离子浓度下青萍生长状况、叶片色素含量以及金属离子浓度对青萍N、P和金属离子吸收能力的影响。结果表明：金属离子浓...     

Bioremediation model for atrazine contaminated agricultural soils using phytoremediation (using Phaseolus vulgaris L.) and a locally adapted microbial consortium

The objective of the present study was to examine a biological model under greenhouse conditions for the bioremediation of atrazine contaminated soils. The model consisted in a combination of phytoremediation (using Phaseolus vulgaris L.) and rhizopheric bio-augmentation using native Trichoderma sp., and Rhizobium sp. microorganisms that showed no inhibitory growth at 10,000 mg L^?1 of herbicide concentration. 33.3 mg of atrazine 50 g^?1 of soil of initial concentration was used and an initial inoculation of 1 × 10⁹ UFC mL^?1 of Rhizobium sp. and 1 × 10⁵ conidia mL^?1 of Trichoderma sp. were set. Four treatments were arranged: Bean + Trichoderma sp. (B+T); Bean + Rhizobium sp. (BR); Bean + Rhizobium sp. + Trichoderma sp. (B+R+T) and Bean (B). 25.51 mg of atrazine 50 g^?1 of soil (76.63%) was removed by the B+T treatment in 40 days (a = 0.050, Tukey). This last indicate that the proposed biological model and methodology developed is useful for atrazine contaminated bioremediation agricultural soils, which can contribute to reduce the effects of agrochemical abuse.     

MTBE的生物降解技术

汽油添加剂甲基叔丁基醚 (MTBE)的污染在国外已引起重视。概述了目前MTBE生物降解的研究现状 ,着重介绍了国外对MTBE污染地下水的异位和原位生物处理方法。随着汽车的逐步普及和MTBE用量的增加 ,我国正在或将面临MTBE的污染。指出了开展相关研究的重要性和迫切性 ,初步提出了这一新课题的研究思路 ,为我国环境保护领域从事该项研究的人员提供参考。     

锑矿区土壤重金属污染及优势植物对重金属的富集特征

通过野外调查采样,分析了冷水江锑矿区4个采样点土壤和优势植物中重金属含量,以及矿区生长的5种优势植物对Sb、As、Cd、Pb、Cu和Zn的的吸收与富集能力及其富集特性。结果表明,矿区土壤中6种重金属元素的平均含量均超出湖南省土壤背景值和全国土壤背景值,土壤受Sb污染最严重,其次是Cd、As的污染。5种优势植物淡竹叶、苎麻、芒草、狗尾草和白背叶体内Sb、As的含量都超过正常范围,具有修复矿区土壤Sb、As污染的潜力。其中苎麻对Sb的富集系数和转运系数均大于1,满足Sb超富集植物的基本特征,可作为生态恢复的先锋植物;芒草对Cd的富集系数和转运系数都大于1,对重金属有较强的耐性,作为重金属污染的修复植物具有较好的应用前景。     

Pb超富集植物金丝草（Pogonatherum crinitum）、柳叶箬（Lsache globosa）

重金属超富集植物是植物修复技术的核心和前提,但目前国内发现的Pb超富集植物较少,本研究通过野外调查和室内胁迫模拟实验相结合的方法,在国内首次发现并证实金丝草和柳叶箬为Pb的超富集植物。野外调查结果表明;金丝草地上部分Pb含量1 231.80 mg/kg,转运系数达到1.32,柳叶箬地上部分Pb含量1 818.40 mg/kg,转运系数6.5。室内模拟胁迫实验表明:在Pb胁迫浓度为5 000 mg/kg时金丝草和柳叶箬对Pb的转运系数均大于1,而且其地上部分Pb含量也超过1 000 mg/kg的水平。在Pb胁迫浓度为18 000 mg/kg时2种植物体内Pb含量达到最大值,金丝草地上部分和地下部分Pb含量分别达3 789.84 mg/kg和4 964.76 mg/kg,柳叶箬地上部分和地下部分Pb含量分别达3 411.56 mg/kg和1 523.02 mg/kg。     

Metabolic responses of weeping willows to selenate and selenite

Goal, Scope and Background Selenium (Se) is one of the most widely distributed elements of the earth’s crust at low concentrations. The extensive use of Se-containing chemicals due to anthropogenic activities has increased the ecological risk to environmental compartments. Plants, under unfavorable environmental conditions, often increase the formation of reactive oxygen species (ROS), and consequently plant antioxidant enzymatic systems have been proposed to be important in plant stress tolerance. The goal of this study was to find out the metabolic responses of plants to Se, to provide quantitative information whether exogenous Se has a beneficial role in plants, and to investigate the potential of vegetation management of Se for potential phytoremediation. Material and Methods Pre-rooted plants of weeping willows (Salix babylonica L.) were grown hydroponically in growth chambers and treated with Na₂SeO₄ or Na₂SeO₃ at 24.0 ± 1°C for 168 h. Five different treatment concentrations were used, ranging from 0.44 to 8.72 mg Se/L for the treatments exposed to SeO₄²⁻ and from 0.50 to 10.0 mg Se/L for the treatments exposed to SeO₃²⁻, respectively. Transpiration rates, soluble protein contents and antioxidative enzyme activities of the plants were monitored to evaluate toxicity from exogenous Se exposure. At the end of the study, total Se in the hydroponic solution was analyzed by hydride generation-atomic fluorescence spectrometry (HG-AFS). Results Both chemical forms of Se at low concentrations showed growth-promoting effects on plants. A significant decrease of transpiration rates and of soluble protein contents of plants was observed at higher Se concentrations after 168 h of exposure. Measurable change of superoxide dismutases (SOD) activity in leaves was only detected under high Se treatments. Catalase (CAT) activity was significantly affected by the Se application. Slight change of peroxidase (POD) activity was measured in all treatments, whereas significant inhibition of POD activity was detected for the plants exposed to SeO₃²⁻ of 10.0 mg Se/L. Se-induced stress appeared in all treatments, thus resulting in measurable increase of glutathione peroxidase (GSH-Px) activity of the plants. Although both chemical forms of Se were taken up by weeping willows efficiently, their uptake rates were different. Discussion Of all measured parameters, POD and CAT activities in leaves were noted the most sensitive indicator for the plants exposed to SeO₄²⁻ and SeO₃²⁻, respectively. Deleterious effects on plant physiological functions due to Se application were not observed over 168 h of exposure. This is largely due to the fact that well-established antioxidant enzymatic systems in plants and higher activities of GSH-Px largely reduced the negative effects on plants; SeO₃²⁻ caused much more severe stress to plants than SeO₄²⁻ at higher Se application rates. The uptake mechanisms between the two chemical species were quite different. Conclusions Neither visible toxic symptoms nor metabolic lesions were observed at low concentrations of Se, probably due to the effective established enzymatic systems in weeping willows. All selected parameters for toxicity determination were significantly correlated to Se application, but metabolic responses of plants to SeO₄²⁻ and SeO₃²⁻ were quite different. GSH-Px in leaves was probably the principle enzyme responsible for stress reduction from Se exposure. Due to their different chemical properties, weeping willows showed a faster uptake rate for SeO₄²⁻ than for SeO₃²⁻. Recommendations Exogenous Se has a beneficial role in plants and vegetation management of Se is a potential remediation strategy in cleaning up Se-contaminated sites. Further investigation on the biochemical mechanism of Se metabolism will provide insight to the specific interactions between Se and plants on the molecular level. Perspectives Weeping willow has a sound potential for phytoremediation of Se-contaminated sediment and groundwater because the tree is not only tolerant to Se but also uptakes chemical species from the environment.     

镉超富集植物筛选研究进展

我国金属矿山、冶炼企业周边土壤镉污染现象十分严重,利用超富集植物修复镉污染土壤有其特殊优势。植物修复方法的关键是选择对镉有耐性和有超富集特性的植物——超富集植物。概述了超富集植物的概念和特征,并对镉超富集植物的筛选工作进展进行了综述。     

不同形态镍盐对生物的毒性效应研究

镍通过提取、加工和使用被释放到环境中,当土壤中镍的含量超过一定值时,就会抑制植物的生长。镍通过有机物产生的络合作用可以提高土壤植物修复的能力。土壤中积滞过量的镍不仅会阻碍植物的生长和发育,同时也威胁到土壤无脊椎动物（如蚯蚓、线虫和跳虫等）和微生物的繁衍与增殖。土壤中重金属的不同形态对植物的毒性效应也有所不同,如Ni、Cu、Cd、Zn、Pb等重金属。以往重金属镍土壤污染研究中,人为添加的镍盐各不相同,有的研究使用氯化镍,有的研究使用硫酸镍或硝酸镍等,均假设毒性相当,其实,阴离子不同,镍盐的毒性也会有差异。     

胺鲜酯与螯合剂GLDA联合强化柳枝稷吸收积累镉效果

为探究己酸二乙氨基乙醇酯（胺鲜酯,DA-6）与谷氨酸二乙酸四钠（GLDA）联用对柳枝稷修复镉（Cd）污染土壤的影响,通过田间试验研究不同DA-6浓度（0和10μmol·L^-1）与不同GLDA施用方式（60 d内将600、1200和2400 kg·hm^-2依次分为1、2和4次施加,分施2和4次的单次间隔时间分别为30 d和15 d）联合对土壤pH及可溶性有机碳（DOC）、柳枝稷生物量及Cd含量、Cd提取量、土壤总Cd及有效态Cd（DTPA-Cd）的影响.结果表明：① DA-6与GLDA联用能提高土壤pH和DOC,且pH和DOC随着GLDA施用量增加而显著增加;②DA-6与GLDA联用能显著提高柳枝稷生物量及Cd含量,其中DA-6和GLDA的施用量与施用次数是影响生物量及Cd含量的最关键因素;③柳枝稷Cd提取量在DA-6浓度为10μmol·L^-1和分4次施加1200 kg·hm^-2GLDA时最高,为22.18 g·hm^-2,较CK（不施加DA-6和GLDA）及10D0（仅叶喷10μmol·L^-1 DA-6）分别提高了1.93倍和1.23倍;④土壤总Cd在DA-6浓度为10μmol·L^-1和分2次施加2400 kg·hm^-2GLDA时最低,为0.529mg·kg^-1,较CK与10D0分别降低21.04%和18.23%.因此,DA-6与GLDA联用能进一步强化柳枝稷修复Cd污染农田.