土壤重金属污染及植物修复技术

土壤重金属污染是当今面临的一个重要环境问题,而土壤重金属污染的植物修复是治理污染土壤的重要手段之一.概括了我国土壤重金属污染现状及危害,论述了重金属污染土壤的植物修复技术原理、类型及其优缺点,并展望了植物修复未来的发展趋势.     

Visualization of copper(II) in velvet mesquite (Prosopis Juliflora-Velutina) and soybeans (Glycine max) by earth field magnetic resonance imaging

The goal of this research was to visualize the uptake of copper by plants to promote phytoremediation. The hypothesis was that regions of the plant that contain more copper have enhanced nuclear magnetic resonance using copper as a paramagnetic contrast agent. Earth field magnetic resonance imaging (EFMRI) spectrometry uses a magnetic field 300,000 times weaker than a 600 MHz nuclear magnetic resonance spectrometer. As in conventional human MRI, this portable instrument is capable of recording one-, two-, and three-dimensional images, although the sample size is reduced. The enhancement of signal was first demonstrated recording the two dimensional images of different concentrations of aqueous copper sulfate. The study also focused on growing mesquite and soybean plants in hydroponic media containing 0.25 mM copper nitrate for four and three weeks, respectively, and recording their EFMRI images with plants grown without copper nitrate. The results showed that EFMRI allows the probing the plant absorption of copper without having to dissect the specimen and therefore requires less sample preparation and time than current techniques. This technique may be beneficial to phytoremediation by imaging plants to evaluate their copper accumulation.     

Impact of organic amendments on aerial biomass production,and phytoavailability and fractionation of copper in a slightly alkaline copper mine tailing

In the process of phytoremediation of mine tailing land, the bioavailability of heavy metals is an important factor. Greenhouse experiment was conducted to assess the availability and uptake of copper (Cu) by maize (Zea mays L.) grown on a slightly alkaline Cu-mine tailing amended with commercial compost and chelators. A second objective was to evaluate the distribution of Cu in cultivated Cu-mine tailings. The experimental design consisted of 12 treatments resulting from the combination of four rates (0, 5, 10 and 20%, by humid weight) of peat moss-shrimp wastes compost and three rates (0, 1.2 and 2.4 dm³) of organic complexing agents applied as a 0.0025 M EDTA + 0.001 M citric acid solution before plant harvest. The results showed that compost and chelators had a positive effect on top biomass production of maize. Compared with the control, the application of compost decreased Cu_CAR and increased Cu_ORG whereas the addition of chelating solution increased Cu_SOL and Cu_EXC and decreased Cu_CAR and Cu_ORG. The Cu lability in cultivated tailing and its availability to the maize plant are highly dependent on the metal speciation in tailing. In another series of experiments, sorption of Cu by cultivated mine tailings were examined. The amounts of Cu sorbed and K _d values were highest in tailing amended with highest compost rate, and were positively correlated with tailing organic matter (OM) content and Cu bound to Cu_ORG. The results indicate that peat moss and shrimp waste containing compost could be used as a phytostabilizer by supplying OM and nutrients and as a sorbent by mitigating Cu uptake by maize. This compost is able to improve the phytoremediation of Cu-mine tailings.     

螯合剂与联合物质在植物修复重金属污染土壤的应用研究进展

为提高螯合剂在植物修复重金属污染土壤的效率,诸如菌根、泥炭、植物激素等联合物质被引入螯合剂联合修复中。文章在研究螯合剂及联合物质在植物修复重金属污染土壤的相关文献基础上,主要对当前已经被研究的螯合剂与联合物质的种类及应用概况进行综述,以期为该领域的深入研究提供参考。     

受污染土壤环境的植物修复技术

植物修复技术是近年来发展迅速的一种非常有前途的污染治理技术.本文介绍了用植物去除土壤中有机污染物和重金属的植物修复技术,并对植物修复技术的未来做了展望.     

赤泥固废土壤化修复研究进展

赤泥产量大、碱性强、综合利用难度大,赤泥处置问题严重限制了氧化铝行业的可持续发展。为减少环境污染和提高资源利用率,赤泥的综合利用得到广泛研究,但是赤泥的无害化处置仍然是亟待解决的问题。土壤化是实现赤泥大宗消纳的一种可行性方法,在综合赤泥土壤化研究现状的基础上,分析了赤泥土壤化处置过程中堆场演化、碱性调控、土壤化调控、植物修复等研究方向存在的问题,并对赤泥土壤化研究方向提出了建议,为赤泥生态修复和无害化处置提供理论和技术指导。     

黑麦草-根内球囊霉联合修复铀污染土壤

针对铀矿周边土壤污染修复问题,植物-微生物联合修复技术具备高效性、环保性优点,能有效解决土壤污染问题而受到人们广泛关注。根内球囊霉(Glomus intraradice,Gi)可与大多数植物形成互利共生的关系,利用Gi接种黑麦草根部修复铀污染土壤。设置Gi接种黑麦草根部与未接种组对照,在不同浓度(18.74、52.15、112.40、202.40mg/kg)铀污染土壤进行修复模拟,探究Gi对黑麦草修复铀污染土壤的强化过程。结果表明,所有铀处理组接种Gi的菌根侵染率均大于50%;生物量显著提升,202.40mg/kg铀处理组中黑麦草地上部分、根部的生物量提升幅度达86%、136%;铀含量、生物富集系数以及吸收氮、磷、钾元素含量均显著提升,但转运系数均低于未接种处理组,说明Gi增强植物根部对铀的富集固定作用,抑制铀由根部向茎叶转移。综上所述,Gi可以增加宿主植物对铀金属毒性的抗逆能力,强化铀污染土壤的植物根部对铀的固定过程,有效提高黑麦草对铀的富集能力。     

植物-电动耦合修复重金属污染土的效能及其强化机制

重金属污染土壤的净化效果直接影响修复后土体的再利用。以Cd、Cu、Ni、Zn、Pb污染土壤为研究对象,采用改进环绕式电极布置,以植物-电动耦合修复下土壤的净化度及土壤性质为重点,厘清关键因素,揭示耦合强化修复机制。结果表明：植物-电动耦合修复下不同重金属的去除率均较单一修复有所提高,重金属赋存形态及植物对重金属的响应是影响修复效果的关键因素。改进环绕式电场的施加能积极调动更大范围土壤中的重金属向植物根系迁移聚集,解决了植物修复中重金属可及性和生物活性低的问题;植物修复的协助有利于改善电动修复对土壤性质的不利影响,解决聚焦效应和高能耗问题。植物-电动耦合修复联合了重金属的空间分布改善、重金属生物利用度提升、植物生长代谢强化及土壤微生物生命活动调节等作用机制,有效提高了重金属污染土壤的净化度,修复后土体可维持稳定的pH值（6.27~7.91）、电导率（108~159 μs/cm）及低能耗（13.76~18.81 kW·h/m³）,有助于推进污染土壤的可持续利用。     

类芦在土壤铅污染修复中的应用前景探讨

以云南某选矿厂类芦为研究对象,就类芦(Neyraudia reynaudiana(kunth.)Keng)对Pb的超富集特性、转运系数、富集系数及生长速度进行了初步研究,结果表明,类芦具有抗逆境能力强、生长迅速、Pb转运系数高等特点,有望调控成为较理想的土壤铅污染植物修复资源.     

矿山废弃地生态恢复研究进展

主要从矿山废弃地的基质改良、植物修复、土壤质量演变以及植被演替这四个研究方向介绍了国内外矿山废弃地生态恢复的最新进展,提出今后研究的重点:一方面是加强对适应面较广的耐受性植物的筛选、培育工作,另一方面是最大限度地保持中国西南矿区的原生态环境、保护生物多样性资源.