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1.
Knowledge about heavy metal release from industrial solid wastes(ISWs) is crucial for better management of their environmental risks. This study was conducted to investigate the effect of organic and inorganic acids, clay minerals, and nanoparticles(NPs) on the release of heavy metals from sugar factory waste, ceramic factory waste, leather factory waste, and stone cutting waste. The influence of the extractants on heavy metal release from these ISWs was in the following descending order: citric acid oxalic acid nitric acid≥ sulfuric acid Ca Cl2. Addition of clay minerals and NPs as adsorbents decreased heavy metal release, which was significantly lower in NP-treated wastes than in the clay mineral-treated wastes. On the other hand, the presence of organic and inorganic acids increased heavy metal adsorption by NPs and clay minerals. These results suggest that NPs can be applied successfully in waste remediation,and organic and inorganic acids play an important role in the removal of heavy metals from the studied adsorbents.  相似文献   

2.
Chemical immobilization is one of the most effective technologies for remediating sites with heavy metals,but the selection of proper immobilization material and determination of its dose ratio is a challenge that limits the remediation efficiency.In this study,we conducted a meta-analysis of 489 independent observations on the immobilization of heavy metals,in which the immobilization materials were divided into biochar,phosphate,lime,metal oxides,and clay minerals.The statistical analysis of t...  相似文献   

3.
Metal contamination in the environment is a global concern due to its high toxicity to living organisms and its worldwide distribution.The principal goal of this review is to examine the current strategies and technologies for the remediation of metalcontaminated soils by metal-accumulating plants and assess the roles of arbuscular mycorrhizal(AM)fungi in remediation of soils under hyperaccumulator or non-accumulator plants.The use of plants to remove metals from the environment or reduce the toxicity,known as phytoremediation,is an environmentally sustainable and low cost remediation technology.The mechanisms of the use of hyperaccumulator plants for phytoremediation included solubilization of the metal in the soil matrix,the plant uptake of the metal,detoxification/chelation and sequestration,and volatilization.Recently,some ecologists have found that phytoremediation with the aids of mycorrhizae can enhance efciency in the removal of toxic metals.AM fungi can facilitate the survival of their host plants growing on metal-contaminated land by enhancing their nutrient acquisition,protecting them from the metal toxicity,absorbing metals,and also enhancing phytostabilization and phytoextraction.Such information may be useful for developing phytoremediation program at metal-contaminated sites.  相似文献   

4.
CHEN TONG-BIN 《土壤圈》1993,3(4):377-382
Soil test for availability of nutrients and heavy metals is extensively served as a means for the evaluations of soil fertility, and environmental effects and phytotoxicity of pollutants in soils, and for the fertilizer recommendation in agricultural and environmental sciences. Therefore, great attention has been paid to the measurement of elemental availability in soil test.  相似文献   

5.
Soil contamination by heavy metal(loid)s is a considerable environmental concern, and immobilization is a promising way to reduce toxicity. In recent years, modified/engineered biochars have gained enormous attention for their use in soil remediation, and various studies have reported notable results from their application and their ability to immobilize heavy metal(loid)s. In this review, a summary of publications on the utilization of modified biochars is presented to address the heavy metal(l...  相似文献   

6.
中国太原市农业土壤的重金属污染状况   总被引:5,自引:0,他引:5  
To evaluate the current state of the environmental quality of agricultural soils in Taiyuan City, a hotspot for China’s industrial development, the concentrations of 8 heavy metals in soils were investigated by means of extensive sampling in farmlands, forestlands, and grasslands in the city. Statistical analyses and spatial distribution maps were used to identify the most significant heavy metal pollutants. The mean concentrations of As, Cd, Cu, Hg, Pb, Zn, Ni, and Cr were slightly higher than their background values in Taiyuan’s topsoil, but were lower than the maximum permissible concentrations in the Chinese Environmental Quality Standard for agricultural soils. Farmland soils in Taiyuan had the highest average Cd, Cu, Hg, Pb, Zn, and Cr concentrations, but the As and Ni concentrations did not differ significantly among the farmland, forestland, and grasslands. Soil contamination by Cd, Cu, Hg, Pb, Zn, and Cr was mainly derived from farming practices, especially the use of sewage water for irrigation. In contrast, As and Ni might derive mainly from the soil parent material. The identification of heavy metal sources in agricultural soils may provide a basis for taking appropriate action to protect soil quality.  相似文献   

7.
The characteristics of the reflectance spectra of clay minerals and their influences on the reflectance spectra of soils are dealt with in the paper.The results showed that dominant clay minerals in soils could be distinguished in light of the spectral -form parameters of the reflectance spectra of soils,thus making it possible to develop a quick method to determine clay minerals by means of reflectance spectra of soils in the lab.and providing a theoretic basis for remote sensing of clay minerals in soils with a high resolution imaging spectrometer.  相似文献   

8.
The environment of estuarine wetlands has been attracting worldwide attention. To study the spatial distribution of pollutants in the tidal flats of the Yangtze Estuary, Southeast China, the Eastern Tidal Flat of Chongming Island (EC) and the Jiuduansha Shoal (JS) of the estuary were selected as the study sites. At each of the two sites, a cross-transect from land to sea was established and topsoil and soil core samples in the cross-transect were collected spatially and seasonally to determine their contents of heavy metals (Cu, Zn, Pb, Cd, Cr, Ni, Mn, and Fe) and grain-size characteristics. The results showed that the heavy metal loads were commonly higher in the soils of nearshore high tidal flats and had a tendency of decreasing from land to sea at both of the study sites. The contents of heavy metals in the soils of the high and medial tidal flats were mostly higher in April and November but lower in July. Corresponding spatial and seasonal variations in grain size of the intertidal soils were also observed at the two study sites. The soils in the nearshore high tidal flats were finer and gradually got coarser seawards; they were relatively finer in April and November but coarser in July. Furthermore, the contents of heavy metals in the intertidal soils of both the sites EC and JS were significantly positively correlated with the clay (<2 μm) and 2-20 μm fractions, but negatively with the sand (>63 μm) and 20-63 μm fractions, which suggested that the heavy metals in the intertidal soils were primarily combined with the fine particulate fraction (<20 μm), especially clay, and hence the spatial and seasonal variations in heavy metals were actually caused by the change of the grain-size characteristics of the intertidal soils due to the different sedimentary environments in the estuary. The results of this study may also contribute to a better understanding of the soil formation and classification in the tidal flats of the Yangtze Estuary.  相似文献   

9.
Mineral Composition and Weathering of Soils Derived from Xiashu Loess   总被引:1,自引:0,他引:1  
Mineralogical, physical and chemical analyses of the soils derived from Xiashu loess were carried out. The primary minerals of these soils were found to be mainly composed of light minerals, such as quartz, feldspar and mica, with traces of heavy minerals. Clay minerals, more complicate in composition, were dominated by hydromica, accompanied by smectite, vermiculite, chlorite, kaolinite, 2:1/1:1 randomly interstratified minerals and small amounts of quartz, goethite, lepidocrocite and hematite, Clay minerals were characterized by low crystallinity and fine particle size. In light of the quartz/feldspars ratio of the 0.01-0.05mm silt fraction, and the clay mineral composition, the freeness of iron oxide, and the silica/sesquioxide and silica/alumina ratios in < 0.002mm clay fraction, it is concluded that the weathering intensity of these soils was lower than those of red soil and yellow earth, but higher than that of brown earth, and that the soil allitization, depotassication and hydroxylation of cl  相似文献   

10.
Natural clay minerals can play an important role in crude remediation of wastewater polluted with the heavy metals (HMs) Cu,Zn and Ni.The presence and timing of addition of natural dissolved organic matter (DOM) have a significant effect on the HM removal by clay mineral sorbents.However,the influence of the presence of DOM on the remediation of the used clay mineral sorbents once saturated with HMs is largely unknown.To resolve this,clay mineral-rich soil column of varying composition,loaded (i) with Cu,Zn and Ni only,(ii) first with DOM followed by Cu,Zn and Ni,or (iii) with DOM,Cu,Zn and Ni simultaneously,was used in a set of desorption experiments.The soil columns were leached with 0.001 mol L-1 CaCl2 dissolved in water as control eluent and 0.001 mol L-1 CaCl2 dissolved in DOM as treatment eluent.During the preceding loading phase of the sorbent,the timing of DOM addition (sequential or concurrent with HMs) was found to have a significant influence on the subsequent removal of the HMs.In particular when the column was loaded with DOM and HMs simultaneously,largely irreversible co-precipitation took place.Our results indicate that the regeneration potential of clay mineral sorbents in wastewater treatment will be significantly reduced when the treated water is rich in DOM.In contrast,in manured agricultural fields (where HMs enter together with DOM),HM mobility will be lower than expected from interaction dynamics of HMs and clay minerals.  相似文献   

11.
综述了铁锰氧化菌诱导成矿对重金属环境行为的影响,分别从铁/锰氧化菌与生物成矿、铁/锰氧化菌诱导铁锰氧化物沉淀耦合重金属稳定化以及铁锰氧化物对土壤中重金属的作用方面进行阐述;并从铁/锰氧化菌生物成矿方式、铁/锰氧化菌诱导生物成矿过程对土壤重金属的稳定化机制等方面进一步总结了铁/锰氧化菌在不同重金属生物成矿修复中的应用,以及微生物诱导成矿过程的调控因素,分析胞外聚合物、温度与酸碱度、共存离子和其他因素对成矿过程的影响,以期为微生物诱导成矿修复重金属污染提供理论参考。未来工作可进一步关注生成矿物稳定重金属的长效性,不同微生物菌群组合对成矿效果的调控,以及铁/锰氧化菌在重金属复合污染场地土壤修复中的应用等方面。  相似文献   

12.
种植单一的超富集植物修复重金属污染土壤,不但中断农业生产导致经济收益降低,而且因生物量较低、修复周期长等诸多弊端导致修复效果不甚理想。间作作为一种传统的农艺管理方式,利用生态位和生物多样性原理等能提高农作物对资源的有效利用,对共植的农作物种类增量提质。在中、轻度污染土壤修复中利用间作体系,通过调控超富集植物与农作物的生长发育,促进超富集植物根系低分子量有机酸(LMWOAs)的分泌,降低其根际土壤p H,增加重金属活性,从而增加超富集植物对重金属的吸收,同时抑制农作物根系LMWOAs的分泌,以减少农作物对重金属的吸收,提高其产量和品质,实现"边生产边修复",提高土地利用率,并增加经济效益。本文根据近几年来国内外相关文献,综述了间作条件下超富集植物和农作物生物量、生理生化响应、重金属吸收、转运、富集等方面的变化,以及间作对土壤环境质量的影响,并对间作修复重金属污染土壤领域的发展趋势,如超富集植物和农作物间作的信号转导和分子生物学机制、间作体系下两类植物根际微生物类群的差异及其功能机制,以及构建高效间作体系提高重金属污染土壤的修复效率等方面进行了展望。  相似文献   

13.
重金属污染农田安全利用:进展与展望   总被引:3,自引:1,他引:2  
我国耕地土壤污染面积广,污染情况复杂,农产品重金属超标问题已经关系到国计民生。常用的物理化学修复方法成本高,不适用于大面积的中低污染农田。植物提取修复方法成本低,环境友好,但修复时间长,推广困难。总的来讲,基于重金属移除的诸技术在解决农田重金属污染方面还没有太大优势。相较而言,农田安全利用在不移除或缓慢移除土壤重金属的条件下,以生产安全农产品为目标,具有更加坚实的现实意义和推广价值。种植低吸收农作物是安全利用的重要措施,基因工程手段在低吸收农作物品种筛选中具有巨大的潜力,但其可能带来的生态环境风险使得这些通过基因工程得到的低吸收作物的田间种植面临着巨大挑战。土壤添加剂可以改变土壤重金属形态,降低重金属的生物有效性,但会对土壤质量产生影响。微生物尤其是土著微生物的利用越发受到关注,改变微生物的生存环境与基因工程手段能够强化微生物的钝化效果。施肥、水分管理、间作等农艺措施也能改变土壤重金属的形态,抑制作物对重金属的吸收。未来以加强推广为目的,多种技术手段的联合应用是重金属污染农田安全利用的重要发展方向,其中以生物技术为核心的利用模式具有十分重要的意义。  相似文献   

14.
重金属污染农田土壤化学钝化修复的稳定性研究进展   总被引:14,自引:2,他引:12  
邢金峰  仓龙  任静华 《土壤》2019,51(2):224-234
化学钝化修复是一种应用广泛的重金属污染农田土壤修复方法,但钝化修复只是暂时降低了土壤中重金属的移动性和生物有效性,随着时间的推移被固定的重金属有可能重新释放到土壤中,因此钝化修复重金属污染土壤的稳定性是重金属污染土壤原位钝化修复成功的关键。本文探讨了钝化修复剂的种类、修复机制、修复稳定性的影响因素以及修复稳定性的研究方法,深入分析了钝化修复稳定性的研究现状和存在问题,并提出今后应加强钝化修复稳定性机制和修复稳定性预测模型的研究,建立和完善科学的钝化修复稳定性的研究方法。  相似文献   

15.

Purpose  

The contamination of agricultural soils by heavy metals is a worldwide problem. Organic amendments can be used for the immobilization and binding of heavy metal ions in soils by complexation, adsorption, and precipitation. A field trial was carried out to evaluate the influence of some low-cost organic materials such as rice straw (RS), green manure (GM), and pig manure (PM) on the distribution of Cu and Cd and the retention of these metals by organic matter fractions in heavy metal-polluted soils.  相似文献   

16.
植物促生长细菌(plant growth-promoting bacteria,PGPB)在植物修复重金属污染土壤的过程中能够有助于植物生长,从而提高植物的重金属污染土壤的修复能力。作为在重金属污染环境中应用的PGPB首先必须具有重金属抗性。镉是一种毒性很高的重金属,也是常见的环境污染因子之一。在植物中,镉抑制根和茎的生长,影响营养吸收和内环境稳定。现已知的PGPB的作用机制之一是产生植物生长激素如吲哚乙酸(indole acetic acid,IAA)和铁载体(siderophore)。本研究从土壤中筛选获得5株具有镉抗性(〉1.55 mmol/L)且产IAA和铁载体的细菌,这5株菌被编号为DJY、TK-2、TK-6、WM-1、PZ-23。在含镉培养基上,所有5种菌对芥菜根均有不同程度的促生长作用,其中TK-2对芥菜幼苗根萌发和下胚轴延伸的促进效果最为显著;促生效应并不由单一因素决定的,而是多种促生因素的统一协调作用的结果。  相似文献   

17.

Purpose

Southern China is an important agricultural production base, as well as an important mineral resource area. There is a big challenge of heavy metal pollution in the soils of this area. Base on the characterizations of cotton and our present results, we discussed the potentiality to remediate the heavy metal-polluted soils through planting cotton in southern China.

Materials and methods

This paper summarises recent research to provide a better understanding of the status and the causes of heavy metal pollution in southern China, compare the applicability of different remediation methods in this area, evaluate tolerance and accumulation of cotton to heavy metals, and discuss the socioeconomic benefits of cotton planting for remediation of heavy metal-polluted soils.

Results and discussion

Human activity could be causing heavy metal pollution in southern China, as lead pollution is the most prevalent and cadmium pollution is the most severe in this area. Physical and chemical methods are used to remediate the heavy metal-polluted soils in southern China, by which treated polluted soils could not satisfactorily address the problems of economic feasibility, “secondary damage” and “secondary pollution”. The use of plants can green the environment to a certain extent, so the phytoremediation method is widely accepted. Cotton does not reach the standard of hyperaccumulation plants but has a relatively large biomass and shows more excellent tolerance ability and enrichment ability to heavy metals. Especially, the Cd concentration is lower in cotton fibre than in other cotton organs.

Conclusions

Cotton may be a potential crop to ameliorate the heavy metal pollution of farmland in southern China. In addition, cotton remediation combining with multiple repair measures of heavy metal pollution would obtain better repair effect and ecological benefits, and agronomic management practices could also effectively enhance cotton-remedied heavy metal-polluted soils.
  相似文献   

18.
镉砷复合污染土壤钝化材料研究进展   总被引:13,自引:3,他引:10  
我国土壤重金属污染严重,尤以镉砷污染最为突出。镉砷复合污染土壤中各元素间表现为拮抗和协同等作用,其有效态含量受土壤pH变化和氧化还原电位等的影响,增加了镉砷复合污染土壤的修复难度,严重威胁我国粮食安全。综述了常见的镉砷复合污染土壤钝化修复材料的优缺点及其对镉砷复合污染土壤钝化修复效果和机理。常见的钝化材料有生物质炭类、磷酸盐类、金属及其氧化物类、含硅类材料、黏土矿物类、有机肥类和新型材料等。有大量研究表明生物质炭材料对镉有良好的吸附效果,为了同时钝化镉砷,通常使用改性生物质炭或与其他材料配合施用,常见的改性/配施材料有金属及其氧化物、黏土矿物、家禽粪便、复合肥等,其钝化反应机制包括离子交换、共沉淀和表面络合等;磷酸盐类主要与铁盐或铁粉配施,通过吸附和同晶替代钝化镉、点位竞争机制钝化砷;金属及其氧化物类多与生物质炭、石灰和黏土矿物等配施,通过专性吸附和共沉淀钝化镉、氧化还原和络合作用等钝化砷;铁硅肥、硅钙肥、硅钾肥等通过共沉淀钝化镉、专性吸附和点位竞争机制钝化砷;黏土矿物中多施用海泡石,主要与金属氧化物和钙镁磷肥等配施,通过离子交换、沉淀和络合反应钝化镉砷;污泥和动物粪便中含有腐殖化程度较高的有机质,主要通过吸附、氧化还原和有机络合以及微生物作用钝化镉砷;此外,富含巯基和氨基、谷聚多以及富含硫和硒的物质也可有效钝化镉砷。本文对镉砷复合污染土壤钝化修复材料进行总结,归纳了镉砷钝化材料特性,以期为镉砷复合污染土壤修复提供一定的指导。  相似文献   

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