镉污染土壤的植物修复及其EDTA调控研究：Ⅰ、镉对富集植物印度芥菜的毒性

本通过温控盆栽试验研究在10－190mg/kg共10个浓度梯度的Cd处理下，印度芥菜生长对Cd的响应，Cd在根与地上部的积累以及在Cd胁迫和毒害条件下对Ca和Zn吸收的影响，结果表明，Cd对印度芥菜生长的毒害浓度在各个生育期各有不同：幼功期与营养生长前期在70－110mg/kg左右；营养生长后期在110mg/kg以上；成熟期在150mg/kg左右。植物吸收的镉随土壤镉处理浓度的增加而增加，本试验中印度茶菜根和叶积累镉最高浓度分别为300和160mg/kg，在Cd胁迫下，印度芥菜吸收的Ca和Zn增加，在Cd毒害条件下，印度芥菜吸收的Ca和Zn下降。认为高浓度的Cd对印度芥菜生产有抑制，但印度芥菜对镉也表现出很强的耐性，这种耐性可与植物体内Cd和Ca，Zn之间的平衡有关。     

镉污染土壤的植物修复及其EDTA调控研究II. EDTA对镉的形态及其生物毒性的影响

本文通过温室盆栽试验研究了10~200 mg/kg共20个浓度梯度的Cd处理下,EDTA加入土壤后对Cd的形态及其生物毒性的影响。在收获前一周加入EDTA,收获后测定植物根和地上部的生物量,以及H2O、NH4NO3和EDTA 3种提取剂提取的Cd浓度。结果表明,EDTA加入土壤一周后,土壤水溶态Cd增加了400倍以上,交换态Cd增加了40倍以上,印度芥菜根和地上部的生长都受到抑制。可能的原因是EDTA增加了土壤中镉的移动性,提高了Cd对植物的毒性。     

镉污染土壤的植物修复及其EDTA调控研究I. 镉对富集植物印度芥菜的毒性

本文通过温室盆栽试验研究了在10~190 mg/kg共10个浓度梯度的Cd处理下,印度芥菜生长对Cd的响应、Cd在根与地上部的积累以及在Cd胁迫和毒害条件下对Ca和Zn吸收的影响。结果表明,Cd对印度芥菜生长的毒害浓度在各个生育期各有不同:幼苗期与营养生长前期在70~110 mg/kg左右;营养生长后期在110 mg/kg以上;成熟期在150 mg/kg左右。植物吸收的镉随土壤镉处理浓度的增加而增加,本试验中印度芥菜根和叶积累镉最高浓度分别为300 和160 mg/kg。在Cd胁迫下,印度芥菜吸收的Ca和Zn增加;在Cd毒害条件下,印度芥菜吸收的Ca和Zn下降。认为高浓度的Cd对印度芥菜生长有抑制,但印度芥菜对镉也表现出很强的耐性,这种耐性可能与植物体内Cd和Ca、Zn之间的平衡有关。     

镉污染土壤植物修复的EDTA调控机理

我们通过温室盆栽试验 ,在不同Cd处理的土壤中加入EDTA ,分析了印度芥菜根和地上部Cd的浓度 ,探讨EDTA进入土壤后对Cd吸收和运输的影响。结果表明 :加入EDTA ,水提取的Cd浓度增加了 40 0倍以上 ,NH4 NO3提取的Cd浓度增加了 40倍以上 ,在土壤Cd浓度较低时 ,EDTA对植物吸收Cd没有显著影响 ,当土壤添加Cd在 1 3 0mgkg- 1以上时 ,加入EDTA显著增加了地上部Cd的浓度。EDTA能增加印度芥菜地上部中Cd的浓度 ,不是由于土壤溶液中Cd浓度增加从而增加了印度芥菜根对Cd的吸收 ,可能是EDTA加入土壤后增加了这些元素在土壤溶液中的浓度 ,从而高浓度的Cd对植物根细胞产生毒害 ,增加了细胞膜的透性后 ,土壤溶液中的络合物得以进入根细胞并随蒸腾作用运输到地上部。     

镉修复土壤中磷酸盐对镉的形态转化和植物吸收的影响

Phosphate was found to have neither influence on Cd transformation nor effect on plant Cd uptake in three Cd-amended upland soils.However,on submerged red earth,high phosphate dressing inhibited the transformation of Cd from exchangeable fraction to other lower-available ones.Cadmium uptake by rice plants increased simultaneously with increasing phosphate supply though plant resistance to Cd also increased at high phosphate level.Application of phosphate as an amendment for Cd-contaminated soil was therefore not recommended in view of the increasing influx of Cd into food chain especially on flooded soils.     

植物修复镉污染土壤的差异性研究

以茶花凤仙和百日草为供试植物,对不同镉浓度条件下两种植物的生物量、镉含量及其对镉的吸收、富集状况进行了研究.结果表明,不同程度镉浓度处理的土壤中生长的茶花凤仙和百日草对镉的吸收和富集特性不同,生物量随土壤镉浓度的升高而升高,但达到一定浓度时,生物量又随土壤镉浓度的升高而降低.茶花凤仙在低浓度区域,富集镉的能力要强于百日草,但是在高浓度区域时,茶花凤仙富集镉的效果却低于百日草的富集效果.本试验中所选的两种植物,百日草和茶花凤仙均没有达到超积累植物要求的标准.     

重金属污染土壤的植物修复研究Ⅲ.金属富集植物Brassica juncea对锌镉的吸收和积累

采用温室盆栽试验研究了印度芥菜对土壤中锌镉污染的忍耐、积累能力 ,以检验这种植物修复Zn、Cd污染土壤的可能性及其潜力。在加入Zn 5 0 0和 1 0 0 0mgkg- 1 的土壤中 ,印度芥菜生长 66天后 ,叶片中积累Zn的平均浓度分别达 2 80和 662mgkg- 1 ,地上部带走的Zn分别为每盆 2 1 95和 341 2 μg。在加入Cd 2 0 0mgkg- 1 的土壤中生长的印度芥菜 ,叶片中积累Cd浓度为 1 61mgkg- 1 ,地上部带走的Cd为每盆 381 μg。和普通植物相比 ,印度芥菜更能将Zn和Cd从根运输到地上部。Zn 5 0 0mgkg- 1 处理的土壤在种植印度芥菜后其NH4NO3提取的Zn显著高于不种植物的处理 ;土壤添加Cd 2 0 0mgkg- 1 的处理NH4NO3提取的Cd也显著高于不种植物的处理 ,可能的原因是植物根分泌出特殊的分泌物 ,专一性地螯合溶解根系附近的难溶态Zn和Cd,从而提高土壤溶液中的浓度。印度芥菜对Zn、Cd有较强的忍耐和富集能力 ,是Zn、Cd污染土壤修复有潜力的植物。     

土壤镉生物毒性的影响因素研究进展

近年来，随着工业三废排放和污水污泥农用的增多，土壤镉污染问题日益严重，而土壤中过量的镉会对作物产生毒害，尤其是在可食部分的残留将会通过食物链危害人类的健康，为此，国内外专家对镉污染毒性的影响因素进行了广泛深入的研究，本对这些研究取得的成果和存在的问题进行了综述。     

重金属污染土壤的植物修复研究：Ⅱ.金属富集植物Brassica Juncea根 …

本文在盆栽试验的基础上研究了不同程度的外源重金单一及复合污染下富金属植物印度芥菜根际土壤中微生物数量的变化。研究结果表明,根际中细菌的数量明显多于放线菌,真菌。细菌生长对重金属和植物生长最敏感,其次为放线菌。含高镉的金属复合污染处理对细菌、线圈的生长有抑制作用,加铜对细菌有刺激效果。在低于重金属致死临界浓度时,植物根率的存在对细菌的数量的影响会大于重金属元素的影响。印度芥菜根际土壤中微生物数量的变     

印度芥菜对土壤Cd,Pb的吸收富集效应及修复潜力研究

通过盆栽试验对比研究了印度芥菜(Brassica juncea)和油菜对复合污染土壤Cd,Pb的吸收富集效应及修复效率.初步探讨印度芥菜品种Wild Garden Pungent Mix净化重金属污染土壤的应用潜力.结果表明:Cd,Pb复合污染条件下,与油菜相比,印度芥菜对重金属Cd,Pb的抗耐性较强,地上部生物量较大,是同处理油菜的1.1～2.0倍.印度芥菜和油菜对重金属Cd,Pb的吸收富集表现出较为一致的特点,并且对土壤中重金属的吸收能力顺序均为Cd＞Pb,对土壤中Cd的吸收达到了100 mg/kg以上.表现出了超富集植物的特性.但相比之下,印度芥菜对土壤中Cd,Pb的吸收富集能力强于油菜.同时通过多元回归分析表明,两种植物对Cd,Pb的吸收不存在复合效应.本研究中,印度芥菜对Cd的净化率为0.35%～9.22%,是同处理下油菜的2.1～3.5倍;印度芥菜对Pb的净化率只有0.015%～0.356%,虽然是同处理下油菜的1.4～5.5倍,但远小于对Cd的净化率.研究表明,该品种印度芥菜具备应用于修复Cd污染土壤的潜力.     

Phytoremediation for soils contaminated by phenanthrene and pyrene with multiple plant species

Purpose  

The remediation of soil polluted by polycyclic aromatic hydrocarbons (PAHs) is of great importance due to the persistence and carcinogenic properties of PAHs. Phytoremediation has been regarded as a promising alternative among suggested approaches. For the establishment of highly effective remediation method and better understanding of the remediation mechanisms by plants, the potentials of three plant species and their planting patterns on the remediation efficacy were studied by pot experiments.     

石灰处理对红壤中镉形态及其毒性的影响

The effect of liming 4 red soils developed from Quaternary red clay and red sandstone on the cadmium forms and its toxicity were investigated. Liming the acid red soils could greatly reduce Cd toxicity to plants because the soluble Cd and organic Cd in the soils decreased significantly while Cd bound to minerals/oxides and residual Cd increased markedly with increasing lime rates (pH).     

Gel permeation chromatography studies on the speciation of lead in solutions of heavily polluted soils

Samples of solutions from soils contaminated with lead as a result of three different processes: natural weathering and dispersion from an ore body, mining and smelting, and sewage sludge-amendment to land, were fractionated on Sephadex gels. Solutions from the sludge-amended soil, dried sludge and calcareous mine soils were found to contain a proportion of lead eluted at the exclusion limit of the gel, accompanied by a peak in U.V. absorbance, implying the occurrence of a high molecular weight organo-lead complex. This fraction was proportionally highest in the solution from the dried sludge sample; however, low molecular weight organic peaks were also accompanied by elution of Pb in all samples except that from the low pH, naturally contaminated site. Association of Pb with organic matter was observed to be greater in samples of soil solution with a higher initial pH and this may be related to increased stability constants for Pb-organo complexes at higher pH.     

The flux of Cd,Cu, Pb and Zn in mining polluted soils

The monitoring of heavy metal deposition onto soils surrounding old Pb-Zn mines in two locations in the UK has shown that relatively large amounts of Cd, Pb, Zn and, in one case, Cu are entering the soil annually. Small particles of ore minerals in windblown mine tailings were found to be contributing up to 1.46 g m^?2 yr^?1 of Pb, 1.41 g m^?2 yr^?1 of Zn and 0.027 g m^?2 yr^?1 of Cd. However, when these inputs from bulk deposition are compared with the concentrations of the same metals within the soil profiles it is apparent that relatively little long-term accumulation is occurring. Metals are being lost from the soil profiles, probably through leaching. A calculated relative retention parameter gave values that ranged from 0.01 to 0.17 for Cd, 0.11 to 0.19 for Zn, 0.32 to 0.63 for Cu and over 1 for Pb. These relative retention values were found to follow the order of electronegativity of the elements concerned: Pb>Cu>Zn>Cd. Distribution coefficient (Kd) values quantifying the adsorptive capacity of the mine soils for Cd and Pb showed marked differences for the two metals (12 to 69 cm³ g^?1 for Cd and 14 to 126 cm³ g^?1 for Pb) and may, in part, account for the two to one hundred-fold variation in the relative retention parameter for the different metals within these soils.     

Effect of pH on chemical forms and plant availability of cadmium,zinc, and lead in polluted soils

The effect of pH on chemical forms and plant availability of heavy metals in three polluted soils was investigated. The soils were adjusted to pH values of 7.0, 6.0, and 4.5, then sequentially extracted so that Cd, Zn, and Pb could be partitioned into five operationally defined chemical fractions: exchangeable, carbonate, Fe-Mn oxide, organic, and residual. Kidney beans were grown in the soils to investigate plant availability of the metals in relation to changes of their levels in chemical forms resulting from alteration of soil pH. Alteration of pH resulted in changes of chemical forms of the metals in the soils, and at lower pH the changes were more significant. When soil pH values were decreased from 7.0 to 4.55, levels of Cd, Zn, and Pb in exchangeable form increased, decreased in carbonates and decreased slightly in Fe-Mn oxide forms. Their levels in organic and residual forms were unchanged. Although concentration of metals in plants increased with reduction in soil pH values, dry matter yields were also restricted, so that the amount of metal uptake were almost similar. The uptake rate of the metals in the exchangeable + carbonate forms was the same for the three elements in all the cases.     

施肥对铅镉污染土壤上芥菜铅镉含量及生理的影响

盆栽试验研究了不同化学肥料组合处理对铅镉污染土壤上芥菜(Brassica juncea)Pb、Cd含量及其生理特性的影响。结果表明, 与对照相比, 各肥料处理在显著提高芥菜生物量的基础上, 显著降低了芥菜地上部Cd含量(P<0.05), 其中碳酸氢铵+磷酸二氢铵+硫酸钾处理的效果最佳, 芥菜Cd含量仅为对照的41.0%; 施肥处理提高了芥菜地上部Pb含量, 但Pb没有健康风险; 施肥提高了叶菜的叶绿素含量, 但丙二醛、脯氨酸、细胞质膜透性与芥菜地上部Pb、Cd含量无显著相关性。重金属污染土壤施肥处理是一种值得推广的降低叶菜有害重金属含量的有效技术。     

Effect of Ni and As on radish tuber cultivated on artificially polluted soils

A pot experiment with step contamination of soil by Ni and As was performed over a 2-year period with radish. Two soils were used (heavy soil – clay-loam – and light soil – sand-loam) and four levels of contamination were selected, based on the natural abundance of the elements in these soils. Addition of Ni or As had a different inhibiting effect due to the soil quality. With Ni, the biomass production was lower in light soil, whereas with As, this reduction of plant growth was stronger in heavy soil. The ultrastructure of Ni and As contaminated tubers was investigated both in the cortical and vascular bundle cells. The cytological study demonstrated that the two pollutants induced ultrastructural changes in mitochondria. They were more obvious in the vascular tissue than in the cortex and were correlated with the growth inhibition observed in both soils. Plant tolerance to Ni and As was coherent with the content of the mobile fractions of the two elements in soil.     

The effects of different amendments on the mobility and toxicity of nickel and copper in polluted soils

The efficiency of different amendments for the remediation of acidic sandy soils contaminated with heavy metals was assessed in a model laboratory experiment with podzols from the Kola Peninsula. The addition of SLOVAKITE®, lime, and vermiculite leads to significant reduction of the acidity and mobility of nickel and copper in polluted soils, as well as an increase in the length and phytomass of shoots and roots of Festuca rubra. The application of superphosphate for the remediation of soils that were polluted with nickel and copper was less helpful, while the apatite and zeolite additives were inefficient.