间作条件下螯合剂对龙葵和大叶井口边草吸收重金属的影响

用室内土培试验方法,在采自田间的Pb、Cd和As复合污染土壤中单作或间作龙葵和大叶井口边草条件下,筛选出修复Pb-Cd-As复合污染土壤较好的种植方式为间作。进一步在间作方式下,研究了外源添加不同浓度EDDS（乙二胺二琥珀酸）、NTA（氨三乙酸）和EDTA（乙二胺四乙酸）对植物吸收Pb、Cd和As的影响。结果表明,间作显著促进了龙葵地上部对Cd的吸收量和大叶井口边草地上部对As的吸收量,间作龙葵地上部吸收Cd和大叶井口边草地上部吸收As含量分别是单作龙葵和大叶井口边草的1.3倍和1.4倍,说明间作龙葵和大叶井口边草比单作更有利于修复Pb-Cd-As复合污染土壤。间作条件下,大叶井口边草对螯合剂的耐性比龙葵更强。3、6、12mmol.kg-1EDTA能极显著增加土壤中Pb、Cd有效态含量,从而促进龙葵地上部对Pb吸收和大叶井口边草地上部对Pb、Cd吸收。EDTA比NTA具有更强的提高土壤Pb、Cd有效态的能力,但对土壤As有效态促进作用与EDTA相比,NTA效果极显著,1.5、3mmol.kg-1NTA处理极显著提高土壤As有效态含量及促进龙葵和大叶井口边草地上部对As吸收。     

间作对不同品种玉米和大叶井口边草吸收积累重金属的影响

采用土壤盆栽试验,研究砷（As）超积累植物大叶井口边草（PteriscreticaL.）与玉米品种云瑞6号（ZeamaysL.Yunrui6）、云瑞8号（ZeamaysL.Yunrui8）、云瑞88号（ZeamaysL.Yunrui88）间作对其吸收积累重金属的影响。结果表明,不同玉米品种对大叶井口边草的生物量都有一定的抑制作用,均不同程度地降低了其生物量。与玉米间作显著提高了大叶井口边草地上部和根部对As、Cd的吸收,同时显著降低了地上部对Pb的吸收,而地下部对Pb的吸收却有明显增加,尤其以云瑞8号的间作效应最显著。与单作相比,间作能显著提高玉米各器官重金属含量,只有云瑞88号的茎中As含量明显降低,由单作的310.89mg.kg-1降低至间作的145.86mg.kg-1。研究初步表明,大叶井口边草与云瑞8号间作可提高修复As、Cd、Pb污染土壤的效率。     

EDTA与EDDS螯合诱导印度芥菜吸取修复重金属复合污染土壤研究

盆栽试验比较研究了EDTA和易降解的EDDS对复合污染土壤中Cu、Zn、Pb、Cd的活化能力及印度芥菜对4种重金属的吸收与转运特征。结果表明:施用量相同的条件下,EDDS活化土壤Cu的能力与EDTA相当;而EDDS活化土壤Zn、Pb、Cd,尤其是活化土壤Pb、Cd的能力小于EDTA,这与两种螯合剂与不同重金属形成螯合物的稳定常数相一致。向复合污染土壤中施入3mmol/kg和6mmol/kgEDDS均可诱导印度芥菜叶中超量积累Cu。本研究中3mmol/kgEDDS的不同施用方式(单次施,分2次和4次施)对印度芥菜叶片Cu含量的影响差异不显著。各处理印度芥菜叶中的重金属浓度要远高于茎中的浓度,茎中的Cu浓度随土壤溶液Cu浓度线性增加,而叶中Cu的浓度随土壤溶液Cu浓度先增加后下降。     

添加螯合剂诱导－栽培红叶菾菜（Beta vulgaris var. cicla L.）修复铅和镉污染土壤效果的研究

以雄安新区安新县重金属污染农田土壤为供试土壤,以Cd超积累植物红叶菾菜（Beta vulgaris var. cicla L.）为供试植物,设置不同浓度EDTA和柠檬酸（0,2.5,5,7.5,10 mmol kg?1）处理进行盆栽试验,探究螯合诱导－红叶菾菜修复Cd、Pb污染土壤的可行性。结果表明:（1）与对照相比,添加EDTA螯合剂使红叶菾菜生长及生物量均受到抑制,一定浓度柠檬酸处理能显著促进植物生长,5 mmol kg?1柠檬酸处理对植物株高、茎粗及生物量与对照相比的上升比例分别为4.52%、44.07%和50%;（2）添加EDTA螯合剂后土壤中Cd、Pb有效态含量相比对照分别提高了108.61% ~ 235.39%、67.98% ~ 224.16%,柠檬酸处理后土壤Cd、Pb有效态含量最大提高了180.07%、186.01%,EDTA对土壤重金属的活化效率显著高于柠檬酸;（3）通过对红叶菾菜地上部Cd、Pb含量及富集系数比较发现,EDTA更能促进红叶菾菜对Pb的吸收,柠檬酸更能促进红叶菾菜对Cd的吸收;（4）螯合剂处理后土壤中铵态氮、有效磷、速效钾含量显著增加。就本文试验条件、供试材料而言,螯合诱导－红叶菾菜修复铅镉复合污染土壤是可行的。     

螯合剂强化棉花对镉污染土壤修复的初步研究

采用土壤盆栽试验研究了4种有机螯合剂柠檬酸(CA)、乙二胺四乙酸(EDTA)、乙二醇双四乙酸(EGTA)和乙二胺二琥珀酸(EDDS)在不同添加量(0,2.5,5,7.5mmol/kg)时对棉花修复镉(Cd)污染土壤的影响。结果表明,添加螯合剂显著提高了土壤水溶态Cd的含量,添加EDTA、EGTA、EDDS 3种螯合剂,使水溶态Cd含量分别提高了46.5~92.2,52.0~101.1,16.7~84.1倍,其中EGTA增加的幅度最大。棉花生长受有机螯合剂种类和添加量的影响,EDDS和EDTA在高添加量(7.5mmol/kg)时对棉花产生较大的毒害作用,但在培养期内添加螯合剂对植株生物量无显著影响。使用螯合剂显著促进棉花植株Cd含量和地上部分的积累量,其中以EGTA处理效果最佳,地上部Cd含量为对照(CK)的4.01~5.20倍。从地上部Cd积累量和转运系数来看,4种螯合剂EGTA效果最好,CA效果最差。依据研究结果,棉花可作为土壤Cd污染修复植物使用,在植株收获前7d左右添加EGTA螯合剂可有效提高棉花对Cd污染土壤的修复效率。     

硫磺对土壤Cd、Pb有效性的影响

采用盆栽试验,以无硫磺处理为对照,研究不同硫磺处理对土壤pH值、有效态Cd和Pb含量,以及对小油菜生物量、植株Cd和Pb含量的影响。结果表明,施用硫磺以后,土壤pH值在30d内明显降低,同时土壤有效态Cd、Pb含量显著升高。随着硫磺施用量的增加,土壤有效态Cd含量升高,不同处理之间差异达5%显著水平。30d时,160mmol/kg硫磺处理土壤有效态Cd含量为0.863mg/kg,比对照增加了1.98倍。小油菜干物质量随硫磺施用量的增加而增加,同时植株Cd含量也显著升高,植株地上部Cd含量最高可达491.35mg/kg,是同时期对照处理的1.64倍。植株吸收的Pb主要分布在地下部,说明试验中种植小油菜未能达到净化Pb污染土壤的目的。总之,施用硫磺具有强化小油菜对Cd的吸收,增强小油菜提取污染土壤Cd效率的功能。     

可降解络合剂及微生物调控对海州香薷修复污染土壤的效应

盆栽试验研究了海州香薷在Cu、Zn、Pb污染土壤上生长和对Cu、Zn、Pb的富集能力,以及调控剂EDDS、壳聚糖和微生物菌剂对海州香薷重金属吸收的影响。结果表明,Cu223mg/kg,Pb232mg/kg,Zn1068mg/kg的重金属复合污染土壤对海州香薷的生长发育没有明显影响。施用EDDS(3mmol/kg土) 微生物制剂处理组海州香薷叶片中Cu含量高达847mg/kg,Zn含量为745mg/kg;Cu吸收量高达6244μg/株,Zn吸收量为5670μg/株,叶片中Cu、Zn的含量和吸收量均极显著高于对照(p<0.01);3mmol/kg土EDDS处理海州香薷茎中Pb含量显著增加(p<0.05),茎中Pb的吸收量亦显著提高(p<0.05),茎秆中Pb的吸收量为274μg/株。微生物制剂或壳聚糖单独处理对海州香薷生长和金属元素吸收均没有明显的效果。     

柠檬酸对鱼腥草吸收累积铅锌矿区土壤中重金属的影响

采用矿区实地田间试验,通过外源添加柠檬酸(1mmol/kg,3mmol/kg,6mmol/kg和9mmol/kg)处理,研究鱼腥草对重金属复合污染土壤Pb、Zn、Cd、Cr和Cu 5种重金属元素的吸收累积特性,并确定最佳的柠檬酸调控浓度。结果表明,柠檬酸添加浓度为1mmol/kg时能显著促进鱼腥草生物量的提高,比对照增产11.64%,其他处理浓度的柠檬酸对鱼腥草生物量有抑制作用,但不显著;柠檬酸处理能显著提高鱼腥草对Pb、Zn、Cd和Cr这4种重金属元素的吸收累积能力,对Pb和Zn吸收累积能力大于Cd和Cr,对Cu的吸收累积无明显促进作用。但当柠檬酸添加浓度为1mmol/kg时每667m2鱼腥草提取Pb、Zn、Cr和Cu的量分别比对照增加了35.16%,34.39%,59.00%和18.93%,对Cd无明显促进作用。鱼腥草在矿区重金属复合污染土壤上能正常生长,并对多种重金属胁迫具有一定的耐受能力和吸收累积能力,可用于矿区重金属复合污染土壤的植物修复。     

污染土壤上水稻生长及对Pb、Cd和As的吸收

通过温室盆栽试验研究了Pb、Cd和As于中国土壤环境质量标准III级水平(Pb:400 mg/kg;Cd:1.0 mg/kg:As:40 mg/kg)时对水稻在3种不同类型土壤上的生长和吸收Pb、Cd及As的影响.结果表明:在红壤上,As处理的稻谷产量显著降低,除Cd处理对稻谷产量影响不大外,其他处理也明显降低了水稻稻谷产量,且 Pb、Cd 的存在加重了As的毒性;对稻草产量只有Pb和Pb-Cd-As两个处理与对照有显著性差异.在乌栅土上,仅As和Pb-Cd-As处理与对照相比明显降低了稻谷产量,而所有复合处理均降低了稻草产量,且对稻草产量影响要大于其对稻谷产量的影响.在青紫泥上各处理影响较小.Cd-As、Pb-Cd和Pbr-Cd-As处理红壤其稻米Cd含量较Cd单独存在时分别增加了15.7%、11.5%和25.6%;红壤上Pb处理显著增加了稻米Pb的含量.但Pb-As处理降低了稻米Pb含量.稻米中重金属含量在3种不同性质土壤上的含量大小顺序为:红壤>青紫泥>乌栅土.     

高羊茅和黑麦草对污染土壤Cd,Pb,Zn的富集特征

以潮褐土为供试土壤,通过模拟试验研究了高羊茅(Festuca arundinacea)和黑麦草(Lolium multif lorum)对复合污染土壤Cd,Pb,Zn的富集特点。结果表明,在土壤Cd,Pb,Zn复合污染处理条件下,高羊茅Cd,Pb,Zn的平均富集量,地上部分别为5.76,19.77,418.18 mg/kg,地下部分别为129.82,256.66,354.66 mg/kg;黑麦草Cd,Pb,Zn的平均富集量,地上部分别为5.57,26.13,467.18 mg/kg,地下部分别为114.53,155.98,513 48 mg/kg。通过方差分析,这两种草坪草的重金属富集量没有显著差异,并且富集规律呈现较为一致的特点。地上部的富集量和土壤重金属含量的离子冲量呈显著的线性相关。这两种草坪草对其重金属的富集能力顺序为:Zn>Cd>Pb,其中对Zn的吸收呈现富集植物的特性规律,当土壤Zn含量>400 mg/kg时,其转运系数>1,地上部对Zn的富集能力很强,可作为Zn污染土壤的修复植物。通过偏相关和多元回归分析表明,这两种草坪草在土壤Cd,Pb,Zn复合污染条件下均未产生复合效应。     

Effects of Chelating Compounds on Mobilization and Phytoextraction of Copper and Lead in Contaminated Soils

Six chelating compounds: ethylenediamine-tetraacetic acid (EDTA), ethylenediamine-N, N'-disuccinic acid (EDDS), tartaric acid, citric acid, glycine and histidine, were tested as potential agents to mobilize copper (Cu) and lead (Pb) from two soils polluted with the emissions from copper smelters. Copper was mobilized with the following efficiency: EDTA > citric and tartaric acids > histidine > EDDS and glycine, while Pb extractability followed the order: EDTA > EDDS >> tartaric and citric acid >> glycine and histidine. With respect to these results, EDTA and EDDS were chosen for a pot experiment on chelate-induced phytoextraction of Cu and Pb by maize (Zea mays). Chelates were applied at the rates of 0.2, 0.5, and 1.0 mmol kg^?1, and this experiment was carried out at two different watering regimes. Both EDTA and EDDS caused significant increase of Cu uptake from soils, but its concentrations in biomass were far below those required for efficient soil remediation. Lead uptake was only slightly affected by chelate application. Losses of Cu from soil by leaching were much higher than those caused by plant uptake.     

石灰性污染土壤中重金属镉、铅的活化研究

为了探讨石灰性污染土壤中重金属的活化方法,选择四种试剂（氯化钠、盐酸、EDDS和柠檬酸）和受镉污染和镉、铅复合污染两种土壤（XX土壤,全镉6.77 mg kg?1,< 0.01 mm颗粒含量9.8%;JY土壤全镉5.72 mg kg?1、全铅312 mg kg?1,< 0.01 mm颗粒含量29.8%）进行室内培养试验。结果表明:对于XX土壤,氯化钠、盐酸、EDDS和柠檬酸对镉均有活化作用,活化效率分别达到71.87%、74.87%、43.27%和22.86%;对于JY土壤,氯化钠、盐酸和EDDS对镉的活化效率分别达到53.44%、48.44%和42.4%,柠檬酸的活化作用不明显,氯化钠、盐酸、EDDS和柠檬酸对JY土壤铅的活化效率分别达到26.49%、25.56%、55.21%和14.81%。土壤质地可能是影响两种土壤中不同试剂重金属活化效率的主要因素。     

Chelate-enhanced phytoextraction and phytostabilization of lead-contaminated soils by carrot (Daucus carota)

The objective of this study was to study the influence of different ethylenediamine tetraacetate (EDTA), nitrilotriacetic acid (NTA) and oxalic acid (HOx) concentrations on tolerance and lead (Pb) accumulation capacity of carrot (Daucus carota). The results indicated that by increasing Pb, NTA and HOx concentrations in the soil, the shoot, taproot and capillary root dry matters increase effectively. In contrary, EDTA caused to reduce capillary roots biomass. EDTA was more effective than NTA and HOx in solubilizing soil Pb. The highest Pb content in shoots (342.2 ± 13.9 mg kg^?1) and taproots (301 ± 15.5 mg kg^?1) occurred in 10 mM EDTA, while it occurred for capillary roots (1620 ± 24.6 mg kg^?1) in 5 mM HOx, when the soil Pb concentration was 800 mg kg^?1. The obtained high phytoextraction and phytostabilization potentials were 1208 (±25.6) and 11.75 (±0.32) g Pb ha^?1 yr^?1 in 10 mmol EDTA kg^?1 soil and no chelate treatments, respectively. It may be concluded that chelate application increases Pb uptake by carrots. Consequently, this plant can be introduced as a hyperaccumulator to phytoextract and phytostabilize Pb from contaminated soils.     

Desorption-complexation-dissolution characteristics of adsorbed cadmium from kaolin by chelators

In order to provide a sound experimental background for the remediation of metal-contaminated soil by chelators, the desorption/complexation/dissolution characteristics of Cd from kaolin as a representative soil component by four chelators (NTA, EDTA, EGTA and DCyTA) have been investigated as a function of solution pH. For all chelating agents under examination, the ratio of Cd (desorbed from kaolin) to chelator was found to be 1:1. The chelation/dissolution of Cd was strongly dependent on the solution pH for NTA and EDTA. In the NTA system, 100% Cd dissolution occurred only at a pH = 8 and pH < 3.2; under weakly acidic conditions only 45% of the Cd on kaolin was dissolved due to readsorption of CdNTA- complex on kaolin. At a pH ≥ 10, Cd dissolution decreased, due to Cd hydroxide precipitation. Only 85% of the total Cd on kaolin desorbed under weakly acidic conditions in the EDTA system, indicating metal complex readsorption similar to that found in the Cd-NTA system. Zeta potential measurements showed that the surface charge of Cd-loaded kaolin became more negative after addition of EDTA and NTA with a shift in the pH at the point of zero charge to a lower value. As compared to the EDTA and NTA systems, DCyTA and EGTA complexed strongly with Cd (100% Cd dissolution) over a wide pH range (2.5–12.0). The zeta potential of kaolin did not change and no Cd readsorption was found after addition of EGTA and DCyTA. The capacity of the four chelators for removing Cd from kaolin was found to be in the order DCyTA > EGTA > EDTA > NTA.     

重金属高污染农田土壤EDTA淋洗条件初探

通过室内振荡淋洗试验研究了乙二胺四乙酸二钠(EDTA)浓度、淋洗时间、液固比、淋洗次数对甘肃省白银市某高污染农田土壤中重金属去除效果的影响,并测定了EDTA淋洗前后土壤中重金属形态的变化。结果表明：淋洗剂浓度和液固比越高、淋洗时间越长、淋洗次数越多,对重金属的去除效果越好。在EDTA浓度为5 mmol/L、液固比为2.5、连续振荡淋洗3次、每次1 h时,对土壤中Cd、Cu、Pb、Zn 4种重金属的总去除率分别为 55.2%、21.9%、19.3% 和20.9%,其中Cd 淋洗效率最高。EDTA对土壤中交换态、碳酸盐结合态和铁锰氧化物结合态重金属的去除效果明显,但不能有效去除有机及硫化物态和残余态土壤重金属。     

EDTA-Enhanced Phytoremediation of Lead-Contaminated Soil by Corn

EDTA-enhanced phytoremediation by corn (Zea mays L.) of soil supplemented with 500 mg L^?1 lead (Pb) was examined. The chelate EDTA was used in order to increase Pb bioavailability at four levels: 0 (control), 0.5 (low), 1.0 (medium), and 2.5 mmol kg^?1 (high). Plants were grown under controlled conditions in a growth-chamber with supplementary light. An EDTA concentration of 5.0 mmol kg^?1 was lethal to plants. At high and medium EDTA levels plants grew significantly less than control ones. Lead concentrations in corn leaves increased with increased EDTA levels. Plants subjected to medium EDTA level had the greatest root to shoot Pb translocation. Plants subjected to high EDTA level showed high phosphorus (P) uptake and translocation within plants. Therefore, possibly it was not only Pb that caused toxic effect on plants, but also the high internal concentration of P that in turn could have complexed active Fe.     

北京市菜地土壤重金属现状分析与评价

近年来北京蔬菜种植业得到迅速发展,已成为农业经济的支柱产业之一。为了解北京地区菜地以重金属为主要指标的土壤环境质量现状,采集北京市主要蔬菜生产区表层土壤(0~20cm),测定镉(Cd)、铅(Pb)、铜(Cu)、铬(Cr)、锌(Zn)、镍(Ni)、汞(Hg)含量和基础理化性质。依照《土壤环境质量标准》和《土壤环境监测技术规范》采用单项和综合污染指数法进行评价,结果表明,与土壤背景值相比,大兴、昌平、密云、延庆、房山、顺义、通州区内Cd、Cr明显富集,顺义区、房山区Cd质量分数平均值接近于《食用农产品产地环境质量评价标准》限量值(0.40 mg/kg),但未超过《土壤环境质量标准》中二级限量值(0.60 mg/kg)。Cd、Cu、Zn、Cr单项污染指数平均值处于0.7~1.0,属于尚清洁(警戒限)水平,且土壤Cd质量分数变异系数极高,40%以上样点存在"轻度"和"中度"污染,设施菜地较裸露菜地相比存在较高Cd污染风险。综上,北京市菜地土壤重金属环境质量指标总体安全,处于非污染状态,但存在一定程度的Cd、Cr、Cu、Zn累积污染风险。     

东方香蒲（Typha orientalis Presl）对重度污染土壤中As、Cd、Pb的耐性与累积特征

通过温室盆栽试验研究东方香蒲对重度污染土壤中As、Cd、Pb的耐受性能与累积特征。研究结果表明,与未污染土壤处理相比,当土壤中As、Cd、Pb含量分别达到48.4、16.9mg·kg-1和316mg·kg-1时,东方香蒲生物量、叶绿素含量和过氧化氢酶活性等均无显著降低,东方香蒲对土壤中As、Cd、Pb表现了较强的耐受性能;当土壤中As、Cd、Pb含量分别达到285、42.1、1008mg·kg-1时,东方香蒲生物量、叶绿素含量和过氧化氢酶活性等均明显下降（P〈0.05）,表现出植株矮小、叶片枯黄等中毒症状。东方香蒲对土壤中As、Cd、Pb的累积主要在根部,其含量分别可达31.69、35.12mg·kg-1和87.12mg·kg-1,而在茎叶中仅为2.06、2.83mg·kg-1和20.18mg·kg-1,根部向地上部转移系数小。研究结果表明,东方香蒲可作为As、Cd、Pb重度污染土壤植物稳定修复的潜在目标植物之一。