改性措施对复合污染土壤重金属行为影响的研究

采用田间实验的方法,研究了在复合污染土壤上石灰＋Ｃａ、Ｍｇ、Ｐ肥处理对重金属迁移、积累的影响及重金属的作物效应．结果表明,在污染土壤上采用石灰＋Ｃａ、Ｍｇ、Ｐ肥处理可减少重金属向作物籽实的迁移和积累,特别是Ｃｄ、Ｐｈ、Ａｓ３元素;改性以后,水稻、小麦Ｃｄ吸收量比改性前降低了３１．５—５５％．４种作物对Ｐｈ的吸收量降低了２３．４－５７．８％,Ｃｕ、Ｚｎ吸收量略有降低．水稻Ａｓ吸收量增加了５６．８％,小麦、大豆Ａｓ吸收量减少６１．８－８１．１％．重金属在土壤中存在的形态发生了变化,Ｃｄ、Ｐｈ、Ｚｎ交换态百分含量不同程度地有所减少,而碳酸盐结合态有所增加,可被植物吸收利用的有效含量降低．     

杨树落叶前后重金属元素内外迁移循环规律研究

供试元素在杨树各部位的含量和贮量为Ｚｎ＞Ｃｕ＞Ａｓ＞Ｐｂ＞Ｃｄ,并与环境中相应元素浓度呈正相关．落叶时元素的迁移主要发生在叶、枝、根和干之间,叶中８～４８％的Ａｓ、Ｚｎ迁移至主干的皮与材中,而Ｃｕ、Ｐｂ、Ｃｄ贮量均有增加,Ｚｎ、Ａｓ的内循环占总循环量的４０％,Ｃｄ、Ｐｂ、Ｃｕ表现为外循环,占总贮量的１７～２７％．同时分析了植物对土壤重金属污染的净化效率．     

重金属复合污染对大豆生长的影响及其综合评价研究

通过正交试验设计研究了溶液培养条件下Ｃｄ、Ｐｈ、Ｃｕ、Ｚｎ、Ａｓ复合污染对大豆幼苗生长的影响．结果表明,复合污染条件下,各元素在根中的积累顺序为ＡＳ＞Ｐｂ＞Ｃｕ＞Ｃｄ＞Ｚｎ,茎叶中为Ｃｄ＞Ｃｕ＞Ｚｎ＞Ａｓ＞Ｐｈ,其交互作用类型决定于元素的投加浓度及其与共存元素的比例,而对其生长发育,ＡＳ和ＣＵ是主要的毒害元素,并指出相对离子强度是复合污染综合效应指示与控制的又一有效指标．     

螯合剂对重金属超量积累植物Thlaspicaerulescens的锌,铜,锰？…

由螯合剂ＥＤＴＡ和ＤＴＰＡ对重金属超量积累植物Ｔｈａｓｐｉｃａｅｒｕｌｅｓｃｅｎｓ吸收Ｚｎ、Ｃｕ、Ｍｎ、Ｆｅ和Ｐ的影响表明：营养液含Ｚｎ１０μｍｏｌ／Ｌ条件下,植株地上部全Ｚｎ含量和根系吸Ｚｎ速率分别达到１６８１ｍｇｋｇ＾－１干重和４４８ｍｇｋｇ＾－１根干重ｄ＾－１;４３．２μｍｏｌ／Ｌ的ＥＤＴＡ或ＤＴＰＡ处理显著抑制植株的生长,也减少植株单位根重吸收的Ｚｎ量,降低地上部和根系全Ｚｎ全Ｃｕ、全Ｍｎ     

重金属复合污染对土壤—植物系统的生态效应II.对作物,苜蓿,树…

研究Ｃｄ、Ｐｂ、Ｃｕ、Ｚｎ、Ａｓ５元素复合污染对农作物、苜蓿、树木吸收元素的影响,供试污染物浓度以接近国内外土壤环境标准值作为高剂量处理,结果表明,５种元素间存在交互作用,可提高作物对Ｃｄ、Ｐｂ、Ｚｎ吸收系数,籽实超出粮食卫生标准的超标率在低剂量处理时Ｃｄ为１６．６￣４２．８５％,高剂量时达１６．６￣７１．４２％。苜蓿茎叶中Ｃｄ、Ｐｂ含量超出饲料卫生标准,树叶中含量也有所增加,在中、酸性土壤上尤甚     

海南岛兴隆地区某些药用植物中的微量元素

本文研究海南兴隆地区１２种不同类型药用植物微量元素的生物吸收系数（Ａｘ）及其含量水平变化特性,结果表明不同科、属、种植物对同一元素的吸收量差异显著,以Ｍｇ＞Ａｌ＞Ｆｅ＞Ｍｎ＞Ｚｎ＞Ｃｕ为序;同属不同品种植物在不同生境中对微量元素的生物吸收系数各有差别,海南槟榔（Ａｘ０．３０×１０－６、１２．５１×１０－６）＞泰国槟榔（Ａｘ０．２９×１０－６、１１．５９×１０－６＞云南槟榔（Ａｘ０．２７×１０－６、１１．５６×１０－６）,元素间吸收量相比以Ｍｏ＞Ｚｎ＞Ｃｕ＞Ｍｎ＞Ｎｉ为例;同种植物不同器官微量元素的吸收量也是不同的,例如巴戟天的含量以根（２１８．４８×１０－６＞叶（１１５．１９×１０－６）＞茎（１１３．０２×１０－６）。植物与土壤中元素含量消长变化关系密切,相比之下,植物中Ｆｅ、Ｍｎ、Ｚｎ含量均高于Ｃｕ、Ｐｈ、Ｎｉ。绞股蓝（１８９．２６）＞巴戟天（１６９．０４）＞益智（１６１．７０）＞槟榔（１５５．８８）。     

植物耐重金属机理研究进展

由于工业“三废”和机动车尾气的排放、污水灌溉及农药、除草剂和化肥的使用,严重地污染了土壤、水质和大气,其中土壤中的重金属（Ｈｇ、Ｃｄ、Ａｓ、Ｃｕ和Ａｌ）污染更为严重［１］。重金属在植物根、茎、叶及籽粒中的大量累积,不仅严重地影响植物的生长和发育［１～...     

海水中Cu、Zn离子对牟氏角毛藻生长的生态效应

研究了Ｃｕ、Ｚｎ离子对车氏角毛藻生长的生态效应．结果表明,Ｃｕ离子活度低于１０－７．８０ｍｏｌ·Ｌ－１时,角毛藻生长繁殖良好,其中以１０－１３．５７～１０－１０．５２ｍｏｌ·Ｌ－１为最好;Ｃｕ离子活度≥１０－７．８０ｍｏｌ·Ｌ－１时产生毒性．低Ｚｎ离子活度未表现出对车氏角毛藻的必需性,Ｚｎ离子活度＞１０－７．００ｍｏｌ·Ｌ－１时不利于生长繁殖．与Ｚｎ离子相比,牟氏角毛藻对Ｃｕ离子的毒性更为敏感．     

水稻—土壤生态系统对Cu,As污染的缓冲作用

通过对冶炼厂区周围水系、土壤和水稻中Ｃｕ、Ａｓ含量分析,探讨其对农田生态环境的影响。结果表明,各稻田耕作层渗出水和相邻塘水中的Ｃｕ平均浓度分别为０．０５９和０．０７０ｍｇ．Ｌ＾－１,Ａｓ为３１．６８和４２．７９μｇ．Ｌ＾－１,稻田土壤中未出现Ｃｕ、Ａｓ明显的梯度累积变化以及水稻能吸收累积相当数量的Ｃｕ、Ａｓ,它们大部分累积在根部,可以认为,水稻土壤生态系统本身对Ｃｕ、Ａｓ污染具有相当大的缓冲作用。     

落叶松落叶前后重金属元素内外迁移循环规律研究

供试元素在落叶松各部位的含量和贮量顺序为Ｚｎ〉Ｃｕ〉Ａｓ〉Ｐｂ〉Ｃｄ,并与环境中相应元素浓度呈正相关。元素的迁移主要发生在叶和枝、干、根之间,落叶时叶中６％的Ｚｎ迁移到枝、干中,且贮量均有增加,存在明显的内循环,占总循环量的２５％;Ｃｕ、Ｐｂ、Ｃｄ、Ａｓ主要为外循环,其循环量占总贮量的２０％￣７１％,循环率分别为３０％、６８％、２７％和２３％。     

农作物体内铅,镉,铜的化学形态研究

本文报道了农作物体内重金属存在的化学形态。用逐步提取法分析了生长在污染土壤上的水稻、小麦的根与叶。结果表明,在两种作物中,根部的铅以活性较低的醋酸可提取态与盐酸可提取态占优势,而叶中的铅以盐酸可提取态占优势。不论根部或叶部,在各种形态镉中,以氯化钠可提取镉所占比例较高,作用较重要。作物体内的铜活性较强,根部以乙醇可提取态占优势,叶中以水提取态占优势。各种结合形态的重金属迁移能力、毒性效应有显著差异。作物体内重金属化学形态特征与其表观毒性效应有密切联系。     

Advances in Cotton Tolerance to Heavy Metal Stress and Applications to Remediate Heavy Metal-Contaminated Farmland Soil

Heavy metal-contaminated soil is one of the major environmental pollution problems of agricultural production and human health in the world. Remediation of heavy metals in soil is one of the most popular research subjects. Different remediation strategies have been reported to remove heavy metals from contaminated soil, among which phytoremediation is the most important one. Compared with other major crops, cotton shows the strongest and most widespread resistance to abiotic stresses, such as heavy metals. Although heavy metal stress adversely affects the growth and development of cotton, cotton possesses a set of sophisticated stress-resistance strategies. As the main product of cotton is nonedible fibers, which have a large biomass and strong heavy metal absorption and enrichment capacities, cotton is an ideal crop to restore heavy metal-contaminated soils and has unique advantages in terms of both ecological and economic benefits, with great application prospects. In this review, based on domestic and foreign research results in recent years, the effects of heavy metals on cotton growth and product quality were analyzed, the heavy metal absorption, accumulation, translocation and enrichment characteristics of cotton plants were summarized, and the adaptation and tolerance mechanisms of cotton to heavy metals were explored. Furthermore, the view that cotton is an effective crop to remediate heavy metal pollution in farmland soil has been proposed, and popularization and application suggestions for planting cotton to repair heavy metal pollution have been put forward to provide a reference for the comprehensive evaluation of the economic feasibility of cotton to repair heavy metal pollution in farmland soil.     

两种农业种植模式对重金属土壤的修复潜力

植物修复农田土壤重金属污染需要经历一个长期的过程,而大部分用来修复的植物都不具备利用价值,不能给当地农民带来经济收入。因此,一些农作物由于其较大的生物量和一定的经济价值,在植物修复土壤重金属污染的应用中受到广泛关注。是在重金属(Cu、Zn、Pb、Cd、As、Hg)复合污染的郴州矿区废弃农田种植油菜、玉米和油葵,研究油菜-玉米和油-油葵两种种植模式对土壤重金属污染的修复潜力。实验结果表明:三种作物在复合污染土壤中对重金属都表现出一定的耐性及吸收积累能力。向日葵的根和叶中重金属Cd、Cu的含量都很高,其中Cd在向日葵的各个部位的富集系数(BCF)及Cu在向日葵的根和叶的富集系数(BCF)都大于1。两种轮作模式对作物的产量没有明显的影响,收获得到的干物质量都很高,每年每公顷分别为油菜16.6t、玉米25.29t、油葵22.5t。两种种植模式都可以对土壤中的重金属进行有效的提取,油菜-油葵种植模式下提取重金属Cu、Pb、Cd、As的量较高,分别为:Cu 2408g hm~(-2)a~(-1),Pb 2027g hm~(-2)a~(-1),Cd 658.5g hm~(-2)a~(-1),As 250g hm~(-2)a~(-1),油菜-玉米模式下Zn和Hg的提取量较高,分别为Zn 4987g hm~(-2)a~(-1)和Hg 7.92g hm~(-2)a~(-1);对于多种重金属复合污染的土壤来说,油菜-油葵的种植模式要优于油菜-玉米的种植模式。总的来说,利用3种作物两两轮作的种植模式,在不影响作物产量的前提下大大的提高了作物对重金属的提取总量。3种作物在收获以后又可以用做工业原料,这就使得当地农民充分利用矿区废弃农田修复污染的同时又能从中获得一定经济效益。     

土壤重金属污染生态过程、效应及修复

本文探讨了重金属在土壤中的行为特性及其生态化学过程作用的特点,不同的重金属元素在土壤胶体颗粒表面的吸附特性及不同元素间的交互作用类型有所不同,自然对重金属迁移积累的影响有所不同。土壤重金属污染影响了种子萌发、幼苗生长、作物产量及体内重金属含量,探讨了污染土壤的酶学评价方法。阐述了重金属污染土壤生物修复的特点,展望了重金属污染生态过程研究的未来发展趋势。     

Effect of simultaneous establishment of Sedum alfredii and Zea mays on heavy metal accumulation in plants

Land application of biosolids to improve agricultural productivity is a cost-effective approach for resource recovery. Unfortunately, municipal biosolids often contain high concentrations of heavy metals, including zinc and copper. In this study, a co-cropping technique was investigated using a known zinc hyperaccumulator, Sedum alfredii with a grain crop, Zea mays. After a 3-mo growth trial, the results indicate that when Z. mays is co-cropped with S. alfredii, heavy metals accumulated in the grains were significantly reduced when compared to monoculture cropping. Co-cropping improved the growth of both plant species. In addition, the biosolids maintained stable pH, N-P-K concentrations, germination potential, and water content after the plant treatment, regardless of the plant species used in the trial. In conclusion, co-cropping with hyperaccumulators may be an effective approach to reducing the risk of contaminant uptake in edible crops.     

Toxicity of Cadmium and nickel in the context of applied activated carbon biochar for improvement in soil fertility

Toxicity induced by heavy metals deteriorates soil fertility status. It also adversely affects the growth and yield of crops. These heavy metals become part of the food chain when crops are cultivated in areas where heavy metals are beyond threshold limits. Cadmium (Cd) and nickel (Ni) are considered the most notorious ones among different heavy metals. The high water solubility of Cd made it a potential toxin for plants and their consumers. Accumulation of Ni in plants, leaves, and fruits also deteriorates their quality and causes cancer in humans when such a Ni-contaminated diet is used regularly. Both Cd and Ni also compete with essential nutrients of plants, making the fertility status of soil poor. To overcome this problem, the use of activated carbon biochar can play a milestone role. In the recent past application of activated carbon biochar is gaining more and more attention. Biochar sorb the Cd and Ni and releases essential micronutrients that are part of its structure. Many micropores and high cation exchange capacity make it the most acceptable organic amendment to improve soil fertility and immobilize Cd and Ni. In addition to improving water and nutrients, soil better microbial proliferation enhances the soil rhizosphere ecosystem and nutrient cycling. This review has covered Cd and Ni harmful effects on crop yield and their immobilization by activated carbon biochar. The focus was made to elaborate on the positive effects of biochar on crop yield and soil health.     

Insights into the Roles of Melatonin in Alleviating Heavy Metal Toxicity in Crop Plants

Alleviating heavy metal pollution in farmland soil, and heavy metal toxicity in plants is the focus of global agricultural environmental research. Melatonin is a kind of indoleamine compound that wide exists in organisms; it is currently known as an endogenous free radical scavenger with the strongest antioxidant effect. As a new plant growth regulator and signaling molecule, melatonin plays an important role in plant resistance to biotic or abiotic stress. Recent studies indicate that melatonin can effectively alleviate heavy metal toxicity in crop plants, which provides a new strategy to minimize heavy metal pollution in crop plants. This study summarizes the research progress on the role of melatonin in alleviating heavy metal toxicity in crop plants and the related physiological and ecological mechanisms such as reducing the concentration of heavy metals in the rhizosphere, fixing and regionally isolating of heavy metals, maintaining the mineral element balance, enhancing the antioxidant defense system and interacting with hormonal signaling. Furthermore, future prospects for the mechanism of melatonin in regulating heavy metal toxicity, the pathway regulating synthesis and catabolism, and the interaction mechanism of melatonin signaling and other phytohormones are presented in this paper, with the goal of providing a theoretical basis for controlling heavy metal ion accumulation in crop plants grown in contaminated soil.     

Removal of trace metals by Sorghum bicolor and Helianthus annuus in a site polluted by industrial wastes: a field experience.

Using the perspective of full scale application of phytoremediation techniques, research is focusing on the optimization of agronomic practices. Two annual high biomass yield crops, Sorghum bicolor and Helianthus annuus, were grown in a polymetallic soil. The experimental site, polluted by pyrite cinders, is located in an industrial site that has been listed in the clean-up national priority list since 2001. Specific aims of this work were to observe the concentration of metals in plants during the crop cycle and to establish the amount of metal removed by the crops. The field trial, arranged in a randomized block design, started in 2005. The concentrations of heavy metals in the soil were: As 309, Cd 4.29, Co 50.9, Cu 1527 and Zn 980mg kg(-1). The crops grown on the polluted soil received mineral fertilization (Fert) and organic amendment (Org), while plants in control soil (Ctrl) did not receive anything. The plots were watered during the crop cycle during two drought periods, using a sprinkler irrigation system. The phytoextraction potential of crops was estimated during the whole growth cycle and the plant biomass that was collected in each sampling date was ICP-analyzed. Plant-biomass growth curves were obtained. The concentrations of the metals in the shoots and in the total plant biomass were recorded. Finally, the metal removal was calculated for the harvestable parts of the crops. The amelioration of the nutritive status of the substrate that resulted, was highly effective for the biomass yield. However, fertilization and soil amendment did not heighten the concentration of metals in the harvestable tissue of the plants during the crop cycle. In some cases, organic matter appeared to bind the elements making them less available for the plants. The evaluation of the potential of phytoremediation of our plants compared to other crops in terms of metal removal was positive. Our results of metal removal are consistent with the results from other in situ experiments. The Zn removal by S. bicolor and H. annuus reached about 2000g ha(-1) and 1000g ha(-1), respectively.     

Evaluation of heavy metals uptake by wheat growing in sewage water irrigated soil

Present research work was carried out in Sahiwal, Sargodha, Pakistan. Diverse treatments of domestic wastewater were used for ascertaining the contamination level in grains of wheat crop. Food crop exposure to heavy metals has been a subject of great concern due to potential health risks to humans. It was observed that increased proportion of wastewater resulted in elevation of heavy metals both in soil and wheat grains. The iron was found to be higher in comparison to all other studied metals in soil. Similarly, wheat grains had high Cd level. Cadmium had the highest values for daily metal intake, health risk index, and pollution load index. Except Co, all metals were positively and significantly correlated between wheat grains and soil. Zinc had the highest bioavailability due to its highest bioconcentration factor. Value of enrichment factor was highest for Mn. It was thus concluded, on the basis of this study, that wastewater-irrigated crops accumulate more metals. Treatment of wastewater prior to application to plants must be commonly practiced to save crops from contamination.