土壤镉污染特征及污染土壤的植物修复技术机理

论述了土壤Cd污染的特点、Cd在土壤中的形态转化特征、生物毒性及我国目前土壤Cd污染现状及危害。系统论述了Cd污染土壤的植物修复治理机理、研究进展及应用前景,并结合我国土壤Cd的污染特点和部分研究结果,提出今后的研究目标和方向。     

镉污染土壤根际环境的调节与植物修复研究进展

简要回顾了近年来土壤镉污染现状,介绍了根际环境的调节作用、镉污染土壤的植物修复技术的类型、特点及植物修复情况,并对今后植物修复发展前景作了进一步展望,为实现对镉污染土壤进行有效的生态整治与安全高效益的利用提供了新的技术途径。     

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。     

影响土壤中镉的植物有效性的因素及镉污染土壤的植物修复

阐述了镉的来源及其对人类的危害,并对影响土壤中镉的植物有效性的土壤因素中的pH、氧化还原电位(Eh)、有机物质、营养物质浓度对镉的植物有效性的作用作了详细的阐述。此外对其它如EDTA、淤泥等对土壤中镉的植物有效性的影响和镉污染土壤的植物修复等方面也进行了综述,并对镉污染土壤的修复治理与趋势进行了展望。     

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。     

金属污染土壤的植物修复

本文就金属污染土壤的植物吸取、植物稳定、植物挥发这三种植物修复技术国际研究与发展的态势作一描述，以进一步推动我国在土壤生物修复这一世界科学前沿领域的研究。     

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.     

农药污染土壤的植物修复研究进展

植物修复是土壤农药污染修复的有效途径之一。植物主要通过直接吸收和代谢、根际土壤植物酶促降解和根际微生物对污染物的降解等三种机制去除土壤中残留的农药。本文简述了植物修复的含义和优点,系统地综述了植物修复农药污染土壤的机理,阐述了利用植物对农药污染土壤进行修复的研究成果和应用,并展望了今后需要进一步研究的领域。     

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

本通过温室盆栽试验研究了10－200mg/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EDTA3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。     

有机污染物污染土壤的植物修复

综述了植物修复土壤有机污染物污染的机理及应用等的研究进展状况，提出了未来植物修复的研究重点。     

Reclamation of Polluted Soil: Phytoremediation Potential of Crop-Related BRASSICA Species

Soils polluted by heavy metals can be reclaimed using a number of expensive tactics that either remove the contaminants or stabilize them within the soil. The value of metal accumulating plants for environmental remediation has recently been appreciated and promising results have been obtained. This paper reports a study on the behavior of Brassica napus, Brassica juncea, Raphanus sativus and Brassica carinata grown on a substrate contaminated by several heavy metals caused by the use of contaminated irrigation water. Data on carbon dioxide assimilation, biomass growth and the bioconcentration and translocation factor of each metal in each species were measured. The polluted substrate caused only a small variation in photosynthesis, however transpiration was more affected by the experimental substrate and in all three species of the genus Brassica the presence of metals in the substrate resulted in higher transpiration levels.Two bioconcentration factors were calculated respectively for the roots (BCF) and the shoots (BCF); the BCF was >1 for all the species for Cd, Cu, Ni and Zn without significant differences among species. All the values of BCF were lower than 0.5; among the metals, all Brassica species demonstrated a similar performance for Cd and Zn, whereas for other elements the bioconcentration factor was very low.     

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.     

香薷植物修复铜污染土壤的研究进展

土壤铜污染有自然来源和人为来源。铜污染土壤中有机质、Fe／Al氧化物对铜的专性吸附，是影响土壤中铜生物有效性的主要因素。近年来，我国原生植物修复材料如海州香薷、鸭跖草、酸模、紫花香薷在国内铜污染土壤的研究中得到广泛应用。其中．采用海州香薷开展铜污染土壤植物修复机理和修复技术的研究，已从实验室水培、盆栽试验的生长反应特性、耐及解铜毒的生理生化反应，进展到室外大田修复的示范工程及技术推广阶段。紫花香薷在重金属复合污染土壤上，也有修复前景。开展植物修复材料的产后处置研究，综合利用和深加工，增大植物修复材料价值，对加强植物修复工程的示范和推广步伐，有重要意义。     

5个蓖麻品种对土壤中镉富集的差异

为了评价能源作物蓖麻对污染农田中重金属镉(Cd)的富集修复能力,本研究以5个蓖麻品种为试验材料,通过大田试验对比了不同蓖麻品种在Cd污染农田中的生长情况、对Cd的富集和转运能力以及对Cd污染土壤的修复能力.结果 表明,5个蓖麻品种在Cd污染农田中生长良好,其中滇蓖2号的株高、茎粗及单株产量显著高于其他品种,分别为440...     

秸秆还田对镉污染农田土壤中镉生物有效性的影响

通过温室盆栽试验和土壤培养试验,研究了重金属镉污染水稻土和人为模拟镉污染土壤上不同种类和不同量的作物秸秆还田后,土壤中可提取态镉的动态变化规律以及对白菜生长和吸收重金属镉的影响。结果表明,秸秆还田显著提高了2种镉污染土壤的pH值。镉污染水稻土上还田玉米和菜豆秸秆显著提高了土壤中醋酸铵提取态镉和DTPA提取态镉含量,秸秆还田后2周时醋酸铵提取态镉含量增加了17%~33%,随时间延长,土壤中可提取态镉增加变的不明显。模拟镉污染土壤上还田玉米和菜豆秸秆对土壤中醋酸铵提取态镉和DTPA提取态镉含量影响不明显。镉污染水稻土上秸秆还田量2%时显著降低了白菜体内镉含量,还田菜豆秸秆和玉米秸秆白菜体内镉含量分别降低了18%和27%。还田玉米秸秆影响了白菜生长,降低了白菜的产量;模拟镉污染土壤上还田菜豆秸秆对白菜生长和镉含量影响不明显,但还田2%玉米秸秆降低了白菜生物量,增加了白菜镉含量。     

耐性植物秸秆覆盖对荠菜生长及镉积累的影响

[目的]研究秸秆覆盖对富集植物重金属积累的影响,筛选能促进荠菜生长和镉积累的镉耐性植物.[方法]通过盆栽试验研究镉污染条件下,覆盖4种镉耐性植物(扬子毛茛、通泉草、邻近风轮菜和车前)秸秆对荠菜生长及镉积累的影响。[结果]覆盖扬子毛茛、通泉草、邻近风轮菜和车前秸秆后,荠菜的地上部分生物量、总生物量和叶片叶绿素含量值均低于未覆盖处理。覆盖扬子毛茛、通泉草、邻近风轮菜和车前秸秆的荠菜总生物量则较未覆盖分别降低了34.04%,49.85%,40.27%和18.39%。只有覆盖邻近风轮菜秸秆提高了荠菜根系镉含量,而覆盖扬子毛茛和通泉草秸秆则提高了荠菜地上部分镉含量(较未覆盖分别提高了18.61%和12.87%)。然而,覆盖4种耐性植物的荠菜根系、地上部分及整株镉积累量均低于未覆盖。[结论]在盆栽条件下,覆盖镉耐性植物(扬子毛茛、通泉草、邻近风轮菜和车前)秸秆不能提高荠菜对镉污染土壤的修复能力。     

赤泥对Cd污染稻田水稻生长及吸收累积Cd的影响

采用田间小区试验,研究了不同赤泥施用量对酸性Cd污染稻田（潮泥田）水稻生长及吸收累积Cd的影响。结果表明,赤泥施用量为4 948 kg·hm-2时水稻产量达到最高,其主要作用是促进了水稻有效穗的形成。同时施用赤泥能显著提高土壤pH,降低土壤有效态Cd含量和减少水稻Cd累积。与不施赤泥的对照相比,施用赤泥3 000 kg·hm-2的处理水稻增产12.4%（P〈0.05）,水稻根Cd降低22.0%（P〈0.05）,糙米Cd（0.14 mg·kg-1）降低40.8%（P〈0.01）,并达到国家粮食卫生标准（GB2715—2005）;当赤泥施用量增至9 000 kg·hm-2时,土壤pH提高12.0%（P〈0.01）,有效态Cd含量降低24.9%（P〈0.05）,水稻根系、茎叶和糙米Cd分别降低55.7%（P〈0.01）、54.5%（P〈0.01）和69.9%（P〈0.01）。表明利用赤泥修复中轻度酸性Cd污染土壤是可行的,并能起到改良土壤和促进水稻增产的效果。试验所用赤泥重金属含量很低,不会造成二次污染。但将赤泥大面积应用于酸性Cd污染稻田还需要系统研究应用参数,并采取农机配套和激励机制来鼓励农民自发行动的积极性。     

Differences in the Influence of Cadmium on the Decomposition of Various Types of Organic Materials in Soil

The influence of Cd on the decomposition of various types of organic materials in soil was studied. CdCl₂ or CaCl₂ (control) was added to a Gley soil at a level of 10 mmol kg^-1 soil. Three days later, organic materials including glutamic acid, glucose, casein, starch, cellulose, lignin, rice straw, rice straw compost, or 3 kinds of sludges were mixed with the soil in a proportion of 1%, respectively. During an 8-week period of incubation at 28°C, CO₂ evolution was measured periodically. At the end of the incubation period, the form of Cd in the soil was analyzed by successive extractions with water, CaCl₂, CH₃COOH, Na₄P₂O₇, and with hot HCl after HNO₃-HClO₄ digestion.

The decomposition of all the organic materials was inhibited by the addition of Cd, but the degree of inhibition varied considerably among the types of organic materials. The decomposition of rice straw, rice straw compost, and sludges was markedly inhibited by Cd. The amount of water-soluble Cd was less in the soils treated with rice straw, rice straw compost, and sludges than in the soils treated with other types of organic materials, while the amounts of CaCI₂-extractable Cd were much larger in the latter soils. In the case of rice straw, rice straw compost, and sludges Cd was easily adsorbed from the CdCl₂ solution.

These results suggest that the inhibition of organic matter decomposition by Cd is caused by the adsorption of Cd onto organic matter.     

微生物对土壤Cd Pb和Zn生物有效性的影响研究

采用土壤盆栽模拟试验方法,研究了接种不同微生物对重金属富集植物——印度芥菜修复土壤中Cd、Pb、Zn的作用效果。结果表明,接入菌株JA27、JC55、JC40不仅显著促进植物的生长,提高印度芥菜的生物量,降低了土壤pH,并且对土壤Cd、Pb、Zn产生活化作用,使土壤Cd、Pb、Zn有效态含量显著增加,增强印度芥菜对土壤Cd、Pb、Zn吸收量,显著提高了富集植物的修复效果。以上3个处理使印度芥菜地上部Cd、Pb、Zn吸收量分别提高了117%～137%、37%～62%、9%～15.1%。接种JB37对土壤Cd、Pb、Zn产生钝化作用,并且抑制印度芥菜对土壤Cd、Pb、Zn的吸收。JB37处理印度芥菜地上部Pb、Zn吸收量分别降低了72.5%、27%,对Cd吸收量无显著影响。