重金属污染土壤修复技术研究进展

本文通过文献分析,介绍了重金属污染土壤常用的物理修复技术、生物修复技术和化学修复技术等技术原理、应用进展及制约因素等,并指出了重金属污染土壤修复技术的研究方向和发展趋势,为重金属污染土壤修复技术的理论研究和应用提供参考。

海泡石和菌根修复重金属污染土壤研究

通过盆栽试验,研究了向重金属Pb、Zn、Cd复合污染的土壤中单一或联合添加海泡石和菌根Glomus mosseae、Glomus intraradices对玉米生长及玉米体内重金属浓度的影响。结果表明:联合使用海泡石和菌根Glomusintraradices可显著增加玉米地上部和根部的生物量;与单一处理相比,联合使用海泡石和两种菌根可使菌根对玉米的侵染率提高44.53%～58.80%。海泡石可有效阻隔土壤中的重金属向植株迁移,从而显著降低玉米体内Pb、Cd、Zn的浓度;而另一方面,两种菌根会促进植株体内Pb、Cd、Zn的富集,因此,可利用这两种菌根和一些非经济性作物来去除土壤中的Pb、Cd、Zn。

生物炭修复重金属污染土壤的研究进展

随着我国工业化进程的逐步加快,重金属污染日益严重,其具有生物相容性、高毒性、不可降解性以及持久性等特点,治理周期长、成本高以及难度大,生物炭活性基团丰富、比表面积大,在重金属修复中具有良好效果。本文主要针对生物炭修复重金属污染土壤的研究进展进行分析和探究,希望给予我国相关领域以些许参考和借鉴。

花生秸秆回收对土壤重金属Cd、Pb、Cr污染的修复效果

为探究花生秸秆对不同重金属的吸收效果,通过温室盆栽实验,设置空白(CK)、低浓度重金属处理(Cd(L):10 mg/kg、Pb(L):5 mg/kg、Cr(L):1 mg/kg)和高浓度重金属处理(Cd(H):20 mg/kg、Pb(H):9 mg/kg、Cr(H):2 mg/kg),分析植物生长指标及秸秆的重金属含量.结果表明,土壤重金属污染降低了花生叶片叶绿素含量、株高及地上和地下生物量,花生秸秆(地上与地下部分)重金属含量随施加重金属浓度的增加而增加.在CK、Cd(L)和Cd(H)处理下,回收单位面积花生秸秆对Cd的吸收量分别为:0.01、0.08 mg/m^(2)和0.19 mg/m^(2);在CK、Pb(L)和Pb(H)处理下,对Pb的吸收量为:0.04、0.16 mg/m^(2)和0.18 mg/m^(2);在CK、Cr(L)和Cr(H)处理下,对Cr的吸收量为:0.004、1.3 mg/m^(2)和1.51 mg/m^(2).研究结果表明,花生秸秆能吸收土壤中的重金属污染物,通过回收花生秸秆可一定程度的修复耕地土壤重金属污染.

基于文献计量的重金属镉污染土壤修复技术研究分析

近年来,随着我国社会经济的快速发展,人们对土壤利用强度的需求越来越大,导致土壤问题越来越严重。目前,有关土壤重金属污染治理技术的研究报道较多,而对该领域的热门方向、未来趋势等的关注则较少。该研究利用CNKI中国知网数据检索方法对土壤重金属镉污染修复进行了计量学分析,明确了该领域的热点方向和趋势,以期为后续学者进行深入研究提供参考。

土壤重金属污染修复技术研究现状及展望研析

随着人类的经济水平逐渐升高,相应的生产活动也不断增加,这样导致土壤受到的污染更加严重,通过相关的数据调查得知,在现如今我国的土壤到重金属的污染已经达到了2000万hm2,这样我国的一些地方的生态又受到了很严重的破坏。土壤重金属污染使得农作物受到损害,从而危害到人类的身体健康,与此同时,重金属阻碍我们的生活质量的提升。所以,对土壤重金属的污染治理技术的研究是较为急迫的,对土壤进行修复能够让我国发展更加快速,同时还能够好的提升综合国力的新型技术。鉴于此,文章结合笔者多年工作经验,对重金属污染土壤修复技术研究的现状与展望提出了一些建议,以供参考。

化工企业遗留污染场地土壤修复项目环境监理实践

环境监理是污染场地修复过程中的关键环节,在我国起步较晚,可供借鉴的实例不多。文章以某化工企业遗留场地污染土壤修复项目环境监理为例,从落实技术方案及审查意见要求入手,重点关注质量控制、二次污染防治和方案变更审核,并提出针对性的环境监理建议,取得了一定的成效,达到了修复目标,为完善我国污染场地修复工程环境监理工作提供借鉴。

生物有机肥对土壤镉形态及玉米镉积累的影响

为探究生物有机肥治理镉污染土壤的可行性及对土壤重金属污染修复的效果,采集河南省淅川县2种镉污染土壤,分别设置6种施肥处理:CK(不施用任何物料)、NPK(常规施NPK肥)、NPK+0.5%OF(常规施肥+0.5%商品有机肥)、NPK+1%OF(NPK+1%商品有机肥)、NPK+0.5%BF(NPK+0.5%生物有机肥)和NPK+1%BF(NPK+1%生物有机肥),测定种植前后土壤全镉含量、土壤各化学形态镉、玉米植株根系及籽粒镉含量。结果显示,以添加1%生物有机肥的治理效果最佳,NPK+1%BF处理下2种土壤有效态镉含量相较于NPK+1%OF降幅分别为19.74%、7.09%;施用有机物料降低土壤弱酸提取态镉含量,提高残渣态镉含量,NPK+1.0%BF弱酸提取态镉含量相比CK下降11%、残渣态镉上升16%;施用有机物料各处理玉米植株根系、籽粒镉含量显著降低,以NPK+1.0%BF处理效果最佳,相比NPK处理,土壤Ⅰ的玉米根系、籽粒镉含量降幅达34.41%、31.59%。综上,在镉污染土壤中施用生物有机肥,可显著降低土壤有效态镉含量,促进土壤弱酸提取态镉向残渣态镉转化,降低镉危害;玉米根系及籽粒镉含量均显著下降,综合治理效果表现为生物有机肥优于商品有机肥。

巨大芽孢杆菌对羽叶鬼针草富集土壤铅的影响

以巨大芽孢杆菌为强化微生物,研究不同微生物浓度对羽叶鬼针草吸收重金属铅的增效。结果表明,相对于未添加微生物的对照组,添加微生物的S_1处理(20 mL菌液)、S_2处理(40 mL菌液),S_3处理(60 mL菌液)地上部分生物富集系数分别提高了15.3%、53.8%、61.5%,地下部分生物富集系数分别提高了25.0%、62.5%、75.0%,说明巨大芽孢杆菌可强化羽叶鬼针草对于铅的吸收,主要可能是微生物的添加可以提高土壤中苹果酸、酒石酸的浓度,从而活化土壤中铅的有效态,并刺激植物根系微生物的活性。研究结果为微生物-植物联合修复重金属土壤提供了一定的理论依据。

不同方法提取的生物质炭可溶性有机物性质研究

为了揭示不同提取方法对生物质炭来源可溶性有机物(DOM)性质的影响,以生物质炭为研究对象,采用多种提取剂、提取方式提取生物质炭DOM,分析其碳含量及化学组成特征。结果表明:低温生物质炭中碱提取物DOC含量较高(15.6~40.0 g/kg),而高温生物质炭中盐提取物较高(0.27~7.04 g/kg)。酸提取物DOM化学组成较为简单,表现为SUVA254、SUVA280值较低,且玉米秆生物质炭中酸提取物亲水性DOM比例(44.6%~73.6%)显著高于水和碱提取物(11.0%~53.2%、0.30%~31.4%)。碱提取物DOM化学组成较复杂,其SUVA_(254)、SUVA_(280)值较高,同时玉米秆生物质炭中碱提取物疏水性DOM比例(68.6%~99.7%)显著高于酸和盐提取物(26.4%~55.4%、0%~46.9%)。该研究揭示了提取剂在生物质炭DOM提取方法中的重要性,而提取方式对其性质影响不显著,可为生物质炭DOM提取方法的选择提供参考。

Research Progress of Phytoremediation Technology on Soils Polluted by Heavy Metals in Mining Areas

Phytoremediation is an efficient and economic ecological technology. It includes phytostabilization, phytovolatilization, and plant absorption. In the research, status quo and progress of Phytostabilization and plant absorption in soils polluted with heavy metals in metal mines were summarized, including the characteristics and status quo of phytoremediation and selection method of hyperaccumulator. In addition, further research was proposed as well.

Effects of Red Mud on the Remediation of Pb, Zn and Cd in Heavy Metal Contaminated Paddy Soil

[Objective] To study the remediation efficiency of red mud on Pb, Zn and Cd in the heavy metal contaminated paddy soil of mine area, to clarify its remediation mechanism and fertilizer efficiency on heavy metal contaminated soil. [Method] The soil incubation experiment was conducted to study the effect of red mud on the pH values and electrical conductivity （EC）, and the remediation efficiency of red mud on lead （Pb）, zinc （Zn） and cadmium （Cd） in heavy metal contaminated soil. [Result] Red mud addition reduced the content of exchangeable Pb, Zn and Cd in the soil significantly. Compared with the control, when incubated for 30, 60 and 90 d with the red mud dosage of 4% （W/W）, the exchangeable Pb content was decreased by 39.25%, 41.38% and 50.19%; exchangeable Zn content was decreased by 49.26%, 57.32% and 47.16%; and exchangeable Cd content was decreased by 19.53%, 24.06% and 25.70%, respectively. The application of red mud had significant impact on the share of Pb, Zn and Cd contents in five forms, and different amounts of red mud application all reduced the proportion of exchangeable Pb, Zn and Cd to the total Pb, Zn and Cd. In addition, the proportion of exchangeable Pb, Zn and Cd to total Pb, Zn and Cd decreased with the increasing amount of red mud addition. [Conclusion] The study provided references for reasonable application of red mud and reduction of heavy metal pollution in paddy soil.

Study Progress in Remediation of Soil Contaminated by Heavy Metals and Its Application Prospect

Flax is an ideal crop for remedying soil contaminated by heavy metals. It has high tolerance to heavy metals and strong adsorption to heavy metals. Through properly using or adjusting external conditions such as regulator, moisture, fertilizer, microorganisms, and pH value, it is able to improve ability of flax to absorb, trans- fer, and accumulate heavy metals. To improve the ability of flax in remediating heavy metal contaminated soil, it is recommended to strengthen cultivation of flax varieties and screening of germplasm resources, actively carry out studies on tech- nologies of fax remedying heavy metal contaminated soil, implement large-scale and mechanized planting of flax, and promote control of heavy metal contaminated soil.

Microbial Remediation of Heavy Metal(loid)Contaminated Soil: A Review

Because of the rapid development of industrial processes, increased urban pollution and agricultural chemicals applied in recent years, heavy metal(loid) pollution in soil has been very serious, and there is an urgent need for fast and efficient removal of heavy metal(loid) pollution. Currently, environmental microorganisms are always used to perform biological alteration or improvement of soils and sewage. Using functional microorganisms that are resistant to toxic heavy metal(loid) ions for alteration and transformation of heavy metal(loid)s in ionic form is an effective measure for microbial remediation of heavy metal(loid)contaminated soil. This paper reviewed the microbial remediation mechanism of heavy metal(loid) contaminated soils, and the approaches for breeding bacteria those can be used for highly efficient removal of heavy metal(loid)s, as well as the application examples of microbial remediation and transformation of heavy metal(loid) contaminated soil, and finally described the future trends and further research work of heavy metal(loid) contaminated soils by microbial remediation.

Use of Sorghum Crops for in Situ Phytoremediation of Polluted Soils

There has been carried out a comparative research, which allow us to determine the quantities and the central points of accumulation ofPb, Cu, Zn and Cd in the vegetative and reproductive organs of the four sorghum varieties （technical sorghtan, sugar sorghum, sudan grass and grain sorghnm）, as well as to ascertain the possibilities for their growth in soils contaminated with heavy metals and their application for phytoremediation purposes. The experimental plots were situated at different distances （0.1 and 15.0 kin） from the source of pollution-the Non-Ferrous Metal Works near Plovdiv, Bulgaria. On reaching commercial ripeness, the crops were gathered and the concentrations of Pb, Cu, Zn and Cd in their different parts-roots, stems, leaves and gains-were determined through dry mineralization. To determine the heavy metal content in the samples, ICP was used. A clearly distinguished trend exists which describes the accumulation of heavy metals within the vegetative and reproductive organs of the studied crops. Sudan grass and technical sorghum accumulated larger heavy metal quantities compared to sugar sorghum and grain sorghum, as the majority of the heavy metals was retained by the roots and a very small amount was translocated to epigeous parts. The depots for accumulation were in the following order： roots 〉 leaves 〉 stems 〉 grains. The studied crops can be related to metal-tolerant crops and can be cultivated on softs which are of low, medium or high contamination with lead, zinc and cadmium, as they do not exhibit a tendency of accumulating these elements in grains at levels above the maximum permissible concentrations for fodder. The selective accumulation of Pb, Cu, Zn and Cd in the roots and the possibility to remove the root-remains makes technical sorghum, sugar sorghum and Sudan grass extremely suitable for phytoremediation purposes. The possible use of grains for animal food guarantees the economic expedience upon the selection of these crops.

Remediation of Heavy Metal-Polluted Agricultural Soils Using Clay Minerals： A Review

Heavy metal contamination of agricultural soils poses risks and hazards to humans. The remediation of heavy metal-polluted soils has become a hot topic in environmental science and engineering. In this review, the application of clay minerals for the remediation of heavy metal-polluted agricultural soils is summarized, in terms of their remediation effects and mechanisms, influencing factors, and future focus. Typical clay minerals, natural sepiolite, palygorskite, and bentonite, have been widely utilized for the in-situ immobilization of heavy metals in soils, especially Cd-polluted paddy soils and wastewater-irrigated farmland soils. Clay minerals are able to increase soil pH, decrease the chemical-extractable fractions and bioavailability of heavy metals in soils, and reduce the heavy metal contents in edible parts of plants. The immobilization effects have been confirmed in field-scale demonstrations and pot trials. Clay minerals can improve the environmental quality of soils and alleviate the hazards of heavy metals to plants. As main factors affecting the immobilization effects, the pH and water condition of soils have drawn academic attention. The remediation mechanisms mainly include liming, precipitation, and sorption effects. However, the molecular mechanisms of microscopic immobilization are unclear. F^ture studies should focus on the long-term stability and improvement of clay minerals in order to obtain a better remediation effect.

Factors Affecting Phytoextraction： A Review

Hyperaccumulators concentrate trace metals and heavy metals in their shoots when grown in metal-contaminated soils and these trace metal-loaded plants may be removed by harvesting the fields. Studies exploring the beneficial role of these hyperaccumulators to clean up the environment have led to the development of phytoextraction. The success of phytoextraction depends upon the high biomass of plant species and bioavailability of metals for plant uptake. The phytoavailability of metals is influenced by soil- associated factors, such as pH, redox potential, cation exchange capacity, soil type, and soil texture, and by plant-associated factors, such as root exudates and root rhizosphere processes （microorganisms）. Efficiency of phytoextraction can be improved by advanced agronomic practices including soil and crop management by application of genetic engineering to enhance the metal tolerance, shoot translocation, accumulation, and sequestration and by application of chelate treatments to enhance metal bioavailability. Application of microorganisms including bacteria and mycorrhiza may facilitate the phytoextraction application at commercially large scale.