首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献，搜索用时 78 毫秒
1.
The selection of appropriate plant species is critical in the successful application of phytoremediation techniques. The present study is an attempt to assess the capability of three brassicaceae, Brassica alba (L.) Rabenh, Brassica carinata A. Braun and Brassica nigra (L.) Koch, for the phytoextraction of Cr, Cu, Pb and Zn from an unpolluted and polluted silty loamy soil added with either Bacillus licheniformis BLMB1 or compost or both. Experiments were conducted in a greenhouse in pots filled with the soils. In all experiments metals were shown to accumulate in shoots and roots of plants grown on polluted soils, and both compost and B. licheniformis BLMB1 strain were able to enhance the accumulation of metals, especially Cr. In particular, Cr accumulation in B. alba resulted higher than the Cr threshold for hyperaccumulator plants (1000 mg kg? 1). This result provides a new plant resource that may have a potential use for phytoextraction of Cr from contaminated soil. However, because of the low bioconcentration factors (< 1) for all studied metals, these species cannot be regarded as suitable for the phytoextraction of excessive Cr, Cu, Pb and Zn from polluted soils. Thus, these species may be used with success only for low metal polluted soils.  相似文献   

2.
Enhanced phytoextraction of heavy metals using chelating agents and agricultural crops is widely discussed as a remediation technique for agricultural soils contaminated with low mobile heavy metals. In this study, phytoextraction efficiency of Zea mays after single and split applications of EDTA was tested on the laboratory and the field scale. EDTA effectively increased the mobility of target heavy metals (Pb and Cd) in the soil solution. Split applications provided generally lower water-soluble levels of Pb and Cd both in the pot and the field experiment. Therefore, the risk of groundwater contamination may be reduced after split applications. Higher Pb and Cd mobilisation after single applications increased plant stress, phytotoxicity and reduced plant dry above-ground biomass production compared to corresponding split doses. Single doses enhanced plant uptake of Pb and Cd and the phytoremediation efficiency compared to corresponding split doses. Results of plant dry above-ground biomass and heavy metal uptake obtained from the pot experiment could be to some extent verified in the field experiment. Plant uptake of Pb and Cd was lower and biomass production dropped after EDTA additions in the field experiment. Remediation factors in the field experiment were in general significantly lower than in the pot experiment mainly due to the much higher mass of soil per plant under field conditions. This highlights the limitations when going from the lab to the field scale. The low phytoremediation efficiency in the field and the mobilisation of high amounts of Pb and Cd down the soil profile may make the use of EDTA and Z. mays not suitable for the remediation of severely heavy metal contaminated soils in a reasonable time frame and may result in substantial groundwater pollution under used crop management.  相似文献   

3.
化学强化可提高超富集植物对土壤重金属的提取效果。采用盆栽试验,研究了可生物降解螯合剂谷氨酸N,N-二乙酸(GLDA)、液体肥的不同用量及复配使用对超富集植物东南景天吸收土壤重金属Cd、Zn的影响,并探讨了其渗滤液对环境的风险。结果表明:单一使用GLDA或者液体肥均能提高东南景天对土壤Cd、Zn的提取效率,其中1.25 mmol/kg GLDA处理的Cd、Zn提取量分别是空白处理的1.36,1.46倍,0.5 g/kg液体肥处理的Cd、Zn提取量分别是空白处理的1.40,1.43倍,这2种低用量单独使用的处理对Cd提取效率最高,达到41%～42%,且对应的渗滤液重金属含量均比空白处理要低,其环境风险较小。GLDA与较高用量(2 g/kg土)液体肥复配时,其东南景天对土壤Cd、Zn的提取量与空白处理相比有所下降。结果表明,GLDA和液体肥在强化植物修复方面有明显潜力,而且以低剂量单独使用强化效果较佳,值得进一步的田间试验核实。  相似文献   

4.
The threat of heavy metal contamination to food and human health in south and east China has become a public concern as industrial development continues. The aims of this study were to investigate the influence of repeated phytoextraction over a two-year period by successive crops of the Zn and Cd hyperaccumulator Sedum plumbizincicola on multiple metal contaminated soils and to assess recovery of soil quality. Total and NH4OAc-extractable Zn and Cd concentrations were significantly reduced in planted soils compared to unplanted soils. Microbial biomass C (Cmic), basal respiration and microbial quotient (qM) were significantly and positively correlated and soil metabolic quotient (qCO2) was negatively correlated with heavy metal concentrations in unplanted soils (P < 0.05). However, Cmic, basal respiration and qM values increased significantly after phytoremediation by five crops over two years compared to unplanted soil. Urease, β-glucosidase, neutral phosphatase and arylsulfatase activities also increased significantly with decreasing heavy metal contents and hydrolase activity was enhanced in planted soil (P < 0.05) compared to the unplanted control. The data indicate the capacity of S. plumbizincicola to extract Zn and Cd from contaminated soil and also that phytoremediation had beneficial effects on soil microbial and hydrolase activities, with the metal phytoextraction procedure restoring soil quality.  相似文献   

5.
Continuous phytoextraction has lately drawn a lot of attention due to its potential for the remediation of metal polluted soils. Although when assessing the success of a phytoextraction process, up till now, emphasis has mostly been placed on metal removal, it is important to highlight that the ultimate objective of a phytoextraction process must be to restore soil health. Consequently, a short-term microcosm study was carried out to evaluate the capacity of an actively growing ecotype of the Zn and Cd hyperaccumulator Thlaspi caerulescens (Lanestosa ecotype) to phytoextract metals from soil and, above all, to assess the potential of soil functional diversity (through the determination of soil enzyme activities and community level physiological profiles) to both determine the toxic effect of metals on soil condition and to monitor the efficiency of a metal phytoextraction process. T. caerulescens plants grown in metal polluted soils showed a shoot metal concentration of 337 mg of Cd, 5670 mg of Zn and 76.6 mg of Pb per kg of dry weight tissue. Apart from confirming its great potential for Zn and Cd phytoextraction, the presence of T. caerulescens, as compared to the metal phytoextraction itself, had the major effect on soil biological parameters. Actually, in metal polluted soils, the presence of T. caerulescens led to a 154, 115, 140, 37 and 164% increase in the activity of β-glucosidase, arylsulphatase, acid phosphatase, alkaline phosphatase and urease, respectively. Metal pollution did not cause a clear inhibition of soil enzyme activities. Contrasting results were obtained with EcoPlates™ versus soil enzyme activities. Actually, the presence of metals led to significantly lower values of Shannon's index calculated from enzyme activities and non-significant higher values of this same index when calculated from EcoPlates™ data. It was concluded that biological indicators of soil health are valid tools to evaluate the success of a metal phytoextraction process.  相似文献   

6.
The current state, problems, and prospects of phymoremediation of heavy metal polluted soils are analyzed. The main attention is paid to the phytoextraction and phytostabilization as the most widespread and alternative methods of soil phytoremediation. The efficiency of phymoremediation is related to the natural capability of plants for the accumulation and translocation of metals, their tolerance to a high content of metals, the plant biomass, and the amendments applied. The advantages and disadvantages of phytoremediation as compared to other methods of remediation of polluted soils in situ are considered. Examples of successful phytoextraction and phytomining for cleaning up of contaminated soils in Rasteburg (South Africa) and the phytostabilization of technogenic barrens nearby the copper-nickel plants in Sudbury (Ontario, Canada) and in the Kola Subarctic (Russia) are presented.  相似文献   

7.

Purpose

The possibility of using chemical and microbial additives to enhance the phytoextraction of mercury (Hg) and arsenic (As) from a multi-contaminated soil could be very effective, leading to a significant saving in terms of time and costs of the reclamation. The aim of this study was to evaluate the efficacy of the addition of (i) thiosulfate and (ii) metal-tolerant bacteria isolated from the polluted soil having plant growth promotion (PGP) potential to perform As and Hg phytoextraction by Brassica juncea and Lupinus albus.

Materials and methods

A collection of 13 bacterial isolates able to tolerate As and Hg was obtained from the contaminated soil, identified by partial 16S rRNA gene sequencing and tested in vitro for PGP activities. The most promising strains were further tested in vivo for the evaluation of plant growth ability and rhizocompetence on model plants. Pot experiments were conducted in microcosms, with polluted soil vegetated with B. juncea and L. albus. Ammonium thiosulfate and potassium dihydrogen phosphate were used as mobilizing agents, together with a bacterial consortium composed by the most promising PGP isolates.

Results and discussion

Thirteen indigenous metal-tolerant bacterial strains were isolated, and their in vitro characterization highlighted their great potential in assisting the phytoremediation process; most of them tolerated both trace elements and showed, at the same time, multiple PGP traits. The results were confirmed in vivo on model plants and lead to the selection of the most promising PGP strains to be applied in microcosm-scale phytoextraction experiments. Thiosulfate addition significantly increased the mobilization of both elements, promoting bioavailability and phytoextraction. When a selected bacterial consortium was supplemented in addition to thiosulfate, the efficacy of the phytoaccumulation was increased up to 85 % for As and up to 45 % for Hg.

Conclusions

The use of the common fertilizer thiosulfate appeared to have great potential in phytoextraction practices since it was able to facilitate the uptake by plants of both Hg and As. Moreover, the application of a consortium of indigenous PGP bacteria (PGPB) produced a further positive effect on the plant biomass, supporting and enhancing the phytoextraction strategy, thus demonstrating their potential in a microbe-assisted phytoremediation intervention.
  相似文献   

8.
The effect of exogenously applied citric acid (CA) on phytoextraction and antioxidant defense was analyzed using willow species (Salix viminalis, S. alba, and S. matsudana) grown in soil contaminated with cadmium (Cd). Citric acid has been used as a chelating agent for the purpose of accelerating the solubility of Cd in soil and enhancing the phytoextraction of selected plants. Willows were exposed to 6 mg/kg of Cd, following the same with citric acid (20 mM/kg soil). Results revealed a positive effect of citric acid in mobilization of accumulated Cd from roots to shoots and leaves. The addition of citric acid alleviated Cd toxicity by helping plants to overcome oxidative stress, through CA’s chelating properties and the increased activity of antioxidant enzymes. Different protection strategies were evident through modification of activities of antioxidant enzymes such as catalase (CAT), ascorbate-peroxidase (APx), and guaiacol peroxidase (GPx) in young versus mature leaves in plants exposed to Cd. Furthermore, results revealed that addition of citric acid may be beneficial in the reduction of the negative effect of Cd stress on photosynthesis. The efficiency of coupling phytoextraction with the chelating agents represents a good strategy for decreasing damages caused by cadmium and has good potential in decontamination of a polluted environment.  相似文献   

9.
This study focused on the potential of using soil enzyme activities and general microbiological rates (respiration, N-mineralisation, nitrification) to evaluate the quality of soils affected by a pyrite mud spill which contained high concentrations of heavy metals. The quality of soils after restoration was estimated by comparing enzyme activities and general microbiological rates in three different types of experimental field plots: (i) non-polluted, (ii) polluted but restored, and (iii) polluted but un-restored soils. Non-polluted soils showed the highest levels of enzyme activity. Significant differences were detected for acid phosphatase, β-glucosidase and urease activities between all types of plots. However, arylsulfatase and alkaline phosphatase activities showed no significant differences between the restored plots and polluted but un-restored plots. Geometric mean statistics were used as an index of soil quality in terms of overall: (i) bioavailable heavy metal concentrations, (ii) assayed enzyme activities, and (iii) general microbiological rates, in order to compare plots differing in the degree of pyritic mud pollution. The results indicate that it is important to consider these three criteria in to estimate the soil quality of heavy-metal contaminated soils. Typically, enzyme activities were negatively correlated with bioavailable Cd, Cu and Zn concentrations, but positively with soil pH values. In contrast, pH values were negatively correlated with bioavailable concentrations of Cd, Cu and Zn. It is unclear if the generalised lower enzyme activities found in restored soils, compared to non-polluted soils, is promoted by pH or bioavailable heavy metals concentrations, or a combination of both.  相似文献   

10.
Arsenic and heavy metal (specifically Cd, Cr, Cu, Ni, Pb, and Zn) uptake, translocation, and accumulation in ten native plant species spontaneously growing in soils polluted by mining activities were studied, with a focus on future phytoremediation work in polluted soils. Plant and soil samples were collected in the vicinity of the Mónica mine (NW Madrid, Spain). Soil analysis showed the ability of native plants for growing in soils with high concentration levels of Cd, Cu, Pb, Zn, and especially As. From these elements, the highest percentage of extractable elements was found for Cd and the lowest for Pb. A highly significant correlation was observed between total and extractable element concentrations in soils, except for Cu, indicating that total concentration is the most relevant factor for element mobility in these soils. Extractable elements in soils were better correlated with concentrations in plants than total elements in soils; thus, extraction methods applied are suitable to estimate the element phytoavailable fraction in soils, which depends on the plant species and not only on the element mobility in soils. High element concentrations were found in the aboveground parts of Corrigiola telephiifolia (As and Pb), Jasione montana (Cd and Zn), and Digitalis thapsi (As, Cd, Cu, Pb and Zn). However, considering the translocation and accumulation factors, together with the concentration levels found in roots and aboveground parts, only C. telephiifolia could be considered a Pb accumulator and an As hyperaccumulator plant, which could be used for future phytoremediation work in soils polluted with As.  相似文献   

11.
Soil heavy metal contamination results in both huge economic loss and severe health problem. Many technologies, such as soil stabilization/solidification, soil excavation, soil washing, chemical extraction and phytoremediation, have been developed to treat soil heavy metal contamination. Among these methods, phytoremediation is usually regarded as a promising, environment-friendly, and cost-effective method. However, little information has been found to support this idea. Hence, in this study, we have conducted a cost-effectiveness analysis of three treatment methods (soil excavation and disposal, soil washing, and phytoextraction) in 16 scenarios of different soil texture, site scale, soil metal, and contamination levels with reviewed literature information. The results have showed that phytoextraction is more cost-effective when dealing with the slightly polluted soils, while soil washing is cost-effective for severely-contaminated scenarios.  相似文献   

12.
刈割对六种牧草吸收重金属和修复污染土壤潜力的研究   总被引：1，自引：0，他引：1  
The pollution of soils by heavy metals has dramatically increased in recent decades. Phytoextraction is a technology that extracts elements from polluted soils using hyperaccumulator plants. The selection of appropriate plant materials is an important factor for successful phytoextraction in field. A field study was conducted to compare the efficiency of six high-biomass forage species in their phytoextraction of heavy metals (Cd, Pb and Zn) from contaminated soil under two harvesting strategies (double harvesting or single harvesting). Among the tested plants, amaranth accumulated the greatest amounts of Cd and Zn, whereas Rumex K-1 had the highest amount of Pb in the shoot under both double and single harvesting. Furthermore, double harvesting significantly increased the shoot biomass of amaranth, sweet sorghum and sudangrass and resulted in higher heavy metal contents in the shoot. Under double harvesting, the total amounts of extracted Cd, Pb and Zn (i.e., in the first plus second crops) for amaranth were 945, 2 650 and 12 400 g ha-1, respectively, the highest recorded among the six plant species. These results indicate that amaranth has great potential for the phytoextraction of Cd from contaminated soils. In addition, the double harvesting method is likely to increase phytoextraction efficiency in practice.  相似文献   

13.
镉污染土壤根际环境的调节与植物修复研究进展   总被引：8，自引：0，他引：8  
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。  相似文献   

14.

Purpose  

Two main pathways of phytoremediation of heavy metal-contaminated soils are phytostabilization and phytoextraction. Some soil amendments can strengthen phytostabilization or phytoextraction through either reducing heavy metal bioavailability in soil or increasing the heavy metal accumulation capacity of the hyperaccumulator (enhancing heavy metal concentration or shoot biomass of the hyperaccumulator). Urea and chicken manure are often used as fertilizers. This research will explore their effects on a newly found hyperaccumulator, Rorippa globosa (Turcz.) Thell., phytoremediating cadmium (Cd).  相似文献   

15.
矿山及周边地区多金属污染土壤修复研究进展   总被引：1，自引：0，他引：1  
本文阐述了矿区多金属污染土壤植物修复的研究现状及其修复实践。结合国内外多金属污染土壤修复技术与机理研究动态,指出当前相关领域研究中存在的主要问题及未来的研究方向;同时考虑矿山及周边地区重金属污染土壤的不同特点,提出今后的重点是开展分别以植物稳定和植物提取为核心的植物-微生物-化学联合修复机理研究及修复体系建设。  相似文献   

16.

Purpose

Effects of phytoextraction by Sedum alfredii H., a native cadmium hyperaccumulator, on metal removal from and microbial property improvement of a multiple heavy metals contaminated soil were studied under greenhouse conditions.

Materials and methods

A rhizobox experiment with an ancient silver-mining ecotype of S. alfredii natively growing in Zhejiang Province, China, was conducted for remediation of a multiple heavy metals contaminated soil. The rhizobox was designed combining the root-shaking method for the separation of rhizospheric vs near-rhizospheric soils and prestratifying method for separation of sublayers rhizospheric soils (0–10 mm from the root) and bulk soil (>10 mm from the root). Soil and plant samplings were carried out after 3 and 6 months of plant growth.

Results and discussion

Cadmium (Cd), zinc (Zn), and lead (Pb) concentrations in shoots were 440.6, 11,893, and 91.2 mg kg?1 after 6 months growth, and Cd, Zn, and Pb removed in the shoots were 0.862, 25.20, and 0.117 mg/plant. Microbial biomass C, basal respiration, urease, acid phosphatase, and invertase activities of the rhizospheric soils were significantly higher than that of unplanted soils after 6 months growth. Microbial biomass carbon (MBC) of 0–2 mm and basal respiration (BR) rate of 0–8 mm sublayer rhizospheric soils were significantly higher than that of bulk soil after 6 months growth. So were the three enzyme activities of 0–4 mm sublayer rhizospheric soils. BR rate and urease were significantly negatively correlated with soluble Cd, so were MBC, acid phosphatase, and intervase activities with soluble Zn, MBC, BR rate, and three enzyme activities with soluble Pb.

Conclusions

Harvesting shoots of S. alfredii could remove remarkable amounts of Cd, Zn, Pb, and lower water-soluble Cd, Zn, and Pb concentrations in the rhizospheric soils. MBC, BR rate, and enzyme activities of the metal polluted soil, especially the rhizospheric soils increased with phytoextraction process, which is attributed to the stimulation of soil microbes by planting as well as the decrease in soil-soluble metal concentration.  相似文献   

17.
Some indica rice varieties are potential phytoextractors for paddy fields polluted with Cd because of their high biomass and because they can accumulate Cd to moderate levels in their shoots. To establish a practical phytoextraction system, phytoextraction using two indica rice cultivars (MORETSU and IR-8) was carried out in a paddy field polluted with moderate Cd levels (2.91 and 2.52 mg kg−1, respectively). The Cd concentration and Cd uptake of MORETSU increased when irrigation water was drained at the maximum tillering stage, and the paddy soil was under oxidative conditions until harvesting. The Cd uptake of MORETSU and IR-8 increased and reached 516 and 657 g ha−1, respectively, at the beginning of October. After phytoextraction using these high Cd accumulating rice varieties for 2 years, the Cd concentration in the paddy field decreased by 18% compared with the initial Cd concentration. The Cd concentration in the rice grains of a japonica ordinary rice variety (HINOHIKARI) subsequently grown on the field after the phytoextraction was lower than the concentration in rice grown on a non-phytoextracted field. These results suggest that phytoextraction using high Cd accumulating rice varieties with early drainage of irrigation water is a practical remediation system for moderate Cd polluted paddy fields in southwest Japan.  相似文献   

18.
The applicability of phytoextraction to remediate soils contaminated with heavy metals (HMs) depends on, amongst others, the duration before remediation is completed. The impact of changes in the HM content in soil occurring during remediation on plant uptake has to be considered in order to obtain a reliable estimate of the phytoextraction duration. To simulate the decrease in the HM content in soil and to assess the resulting decrease in the uptake of HMs by plants, contaminated soil was mixed with uncontaminated, but otherwise similar soil. Uptake of Cd, Pb, and Zn by the indicator plant Lupinus hartwegii and the Zn hyperaccumulator Thlaspi caerulescens (La Calamine ecotype) was a log-linear function of the in-situ measured HM soil solution concentrations. Over a wide range in dissolved Cd and Zn concentrations, uptake of these HMs by T. caerulescens was (much) greater than by L. hartwegii. Experimentally derived regression models describing the relationships between soil, soil solution, and plant were implemented in a HM mass balance model used to obtain estimates of the phytoextraction duration. For our target soils, estimates of the Cd phytoextraction duration using L. hartwegii or T. caerulescens increased significantly by more than 100 or 50 years when experimental soil—soil solution—plant relationships were used instead of the assumption of constant plant uptake of Cd. The two approaches gave similar results for phytoextraction of Zn by T. caerulescens.  相似文献   

19.
Laboratory batch and greenhouse pot experiments were conducted to determine the extraction efficiency of ethylenediaminetetraacetic acid (EDTA) for solubilizing lead (Pb) and cadmium (Cd) and to explore the natural and chemically induced Pb and Cd phytoextraction efficiencies of spinach and mustard after EDTA application. The EDTA was applied at 0, 1.25, 2.5, and 5.0 mM kg?1 soil in three replicates. Addition of EDTA increased significantly the soluble fraction Pb and Cd over the control and maximum increases for Pb (1.42- and 1.96-fold) and Cd (1.45- and 1.38-fold) were observed with the addition of 5.0 mM EDTA kg?1 in Gujranwala and Pacca soils, respectively. Similarly, addition of EDTA increased significantly the Pb and Cd concentrations in the plant shoots, soil solution, bioconcentration factor, and phytoextraction rate. Mustard exhibited better results than spinach when extracting Pb and Cd from both contaminated soils.  相似文献   

20.
Bioaugmentation is a promising method for assisting phytoextraction of heavy metals from contaminated soil, and the development of bioaugmentation-assisted phytoextraction requires the understanding of the mechanism involved in the interaction between plants and inocula. In this study, a pot study was conducted to evaluate the effect of bacterial endophyte Pseudomonas sp. Lk9 which can produce biosurfactants, siderophores and organic acids on the growth and metal uptake of Cd-hyperaccumulator Solanum nigrum L. growing in multi-metal-contaminated soil. The results revealed that Lk9 inoculation could improve soil Fe and P mineral nutrition supplies, enhance soil heavy metal availability, and affect host-mediated low-molecular-weight organic acids secretion, thereby significantly increasing S. nigrum shoot dry biomass by 14% and the total of Cd by 46.6%, Zn by 16.4% and Cu by 16.0% accumulated in aerial parts, compared to those of non-inoculated control. The assessment of phytoextraction showed that Lk9 inoculation elevated the bioaccumulation factor of Cd (28.9%) and phytoextraction rates of all metals (17.4%, 48.6% and 104.6% for Cd, Zn and Cu, respectively), while the translocation factors had negligible difference between Lk9 inoculation (3.30, 0.50 and 0.40 for Cd, Zn and Cu, respectively) and non-inoculated control (2.95, 0.53 and 0.42 for Cd, Zn and Cu, respectively). It was also found that the symbiotic association between S. nigrum and Lk9 significantly increased the soil microbial biomass C by 39.2% and acid phosphatase activity by 28.6% compared to those in S. nigrum without Lk9. This study would provide a new insight into the bioaugmentation-assisted phytoextraction of heavy metal-contaminated soils.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号