土壤重金属污染现状与植物修复研究

概括了中国土壤重金属污染现状以及危害,总结了土壤重金属污染的植物修复类型和优缺点,超富集植物的研究进展重点阐述了植物对土壤重金属耐性和富集机制,以及超富集植物的种质资源,最后指出了植物修复未来的研究趋势。     

土壤重金属污染的植物修复及超富集植物的研究进展

土壤重金属污染的植物修复是污染整治的重要手段之一。近年来对植物修复的研究日益增加,工业、农业和交通是土壤中污染物的三大主要来源。目前重金属污染土壤植物修复主要包括植物稳定、植物提取和植物挥发。由于超富集植物存在生物量小、生长缓慢的缺点,更应该关注具有高生物量的重金属耐(抗)性植物。     

超富集植物修复土壤重金属污染及强化措施研究进展

土壤重金属污染是当前亟须解决的问题。与其他修复技术相比,植物修复因其具有环境友好且不产生二次污染等优点而备受关注。超富集植物是一类具有特殊生理特性的植物,对土壤重金属等有害物质的吸附能力远高于普通植物,具有高积累性和高耐受性的特点。超富集植物的修复存在修复周期过长、修复效率低和修复目标较为单一等局限性,因此施行一系列强化措施成为促进植物高效修复的有效途径。分析了当前重金属污染和修复技术特点,综述了重金属超富集植物研究现状和强化措施,并对此进行了总结与展望。     

石油污染土壤植物修复的影响因素

为修复石油开采工艺过程中对环境土壤造成的污染,对植物修复土壤方法进行盆栽实验。采用紫花苜蓿和多花黑麦草两种植物,对油田固体污染物进行植物修复实验,并考察石油污染土壤的不同比例系数稀释对比和紫花苜蓿、多花黑麦草两种不同科类植物的修复效果。研究结果表明:紫花苜蓿、多花黑麦草对重金属的富集迁移效果明显,提高了生物可利用性,降低了土壤毒理性。     

应用植物重金属超富集机理修复土壤复合污染的研究现状与展望

超积累植物在修复土壤重金属污染中起着重要的作用,但由于重金属复合污染的存在,许多植物并未能完全适用于实际修复中。本文通过阐述土壤重金属复合污染,参考近年来国际上对超积累植物富集机理的研究,从土壤重金属复合污染自身的交互作用,超积累植物根系活化机理,吸收和运输通道机制,金属配位体的运输与解毒作用,以及细胞分室化现象等各个阶段探讨与展望土壤重金属复合污染修复研究问题。     

重金属污染土壤的螯合诱导植物修复技术研究进展

土壤重金属污染来源广泛、危害严重、治理困难,已经成为环境污染中的难点、热点问题。重金属污染土壤的螯合诱导植物修复技术有着绿色环保、经济高效等优点,在污染土壤修复领域具有很大的发展空间。本文综述了螯合诱导修复技术的原理,从螯合剂的选用、超富集植物的筛选、土壤pH值的调节以及田间措施的实施4个方面介绍了螯合诱导修复技术的限制因素,最后对存在问题进行了探讨,并以螯合诱导修复技术理论研究和实践应用2个方面为着力点,详细叙述了此项技术的发展方向和应用前景。     

规模化农田土壤重金属污染修复的中试试验研究——以某镇土壤污染治理为例

农用地重金属污染长期以来一直是生态环境的热点和难点问题。2017年,对某镇农田土壤重金属污染开展详查,单项污染指数评价结果表明,镉超标率为67.60%(Pi>1),基于内梅罗污染指数法的评价结果显示,57.30%的点位受到不同程度的污染(PN≥1.0);2018年,分别选取钝化修复和植物修复进行中试试验,经钝化修复后土壤有效镉和总镉含量分别平均降低32.73%和5.64%。经超富集植物籽粒笕种植一季修复后,土壤总镉含量降低15%以上。本次中试试验修复效果良好,能为下一阶段的土壤镉污染修复方案的制定和优化提供科学的依据,为全国农用地重金属污染修复提供了有价值的借鉴意义。     

规模化农田土壤重金属污染修复的中试试验研究——以某镇土壤污染治理为例

农用地重金属污染长期以来一直是生态环境的热点和难点问题。2017年,对某镇农田土壤重金属污染开展详查,单项污染指数评价结果表明,镉超标率为67.60%(Pi>1),基于内梅罗污染指数法的评价结果显示,57.30%的点位受到不同程度的污染(PN≥1.0);2018年,分别选取钝化修复和植物修复进行中试试验,经钝化修复后土壤有效镉和总镉含量分别平均降低32.73%和5.64%。经超富集植物籽粒笕种植一季修复后,土壤总镉含量降低15%以上。本次中试试验修复效果良好,能为下一阶段的土壤镉污染修复方案的制定和优化提供科学的依据,为全国农用地重金属污染修复提供了有价值的借鉴意义。     

土壤重金属污染及其修复技术研究

土壤重金属污染物有汞、镉、铅、锌等,主要来源于交通运输、工业污染和农业污染。土壤重金属污染会导致农作物减产甚至死亡,对人体健康也会产生极大危害。目前土壤重金属污染修复的技术主要包括工程修复法、物理化学修复法、化学修复法和生物修复法。植物修复技术作为一种新兴的绿色、生态、高效的修复技术具有良好的发展前景。     

植物修复PAHs污染土壤的强化技术研究进展

PAHs是具有"三致"作用且严重威胁生态环境和人类健康的危险污染物.植物修复作为一种绿色经济的修复技术,被广泛应用于PAHs污染土壤的治理中.综述了植物修复PAHs污染土壤的效能、机制及有关强化技术的研究现状,为提高植物修复PAHs污染土壤的有效性提供思路.     

Phytoextraction of toxic metals: a review of biological mechanisms

Remediation of sites contaminated with toxic metals is particularly challenging. Unlike organic compounds, metals cannot be degraded, and the cleanup usually requires their removal. However, this energy-intensive approach can be prohibitively expensive. In addition, the metal removing process often employs stringent physicochemical agents which can dramatically inhibit soil fertility with subsequent negative impacts on the ecosystem. Phytoremediation has been proposed as a cost-effective, environmental-friendly alternative technology. A great deal of research indicates that plants have the genetic potential to remove many toxic metals from the soil. Despite this potential, phytoremediation is yet to become a commercially available technology. Progress in the field is hindered by a lack of understanding of complex interactions in the rhizosphere and plant-based mechanisms which allow metal translocation and accumulation in plants. In this paper, four research areas relevant to metal phytoextraction from contaminated soil are reviewed. The review concludes with an assessment of the current status of technology deployment and suggestions for future phytoremediation research.     

Producing biogas from agricultural residues generated during phytoremediation process: Possibility,threshold, and challenges

In the past decades, a novel strategy has arisen, as required by time, to get a rational production of biogas from contaminated biomass, which may be, on purpose, harvested from contaminated soil phytoremediation process. The present review focuses on the possibility and potential of utilizing the agricultural residues generated during phytoremediation for production of biogas. As a general result of the studies compiled in this review, the harvested biomass can subsequently be utilized for the winning of biogas, and it provides a solution of waste disposal for phytoremediation technology. According to the analysis of previous results, not more than 1 mg/L of cadmium in fermenters shows promoting or at least no inhibitory effect on cumulative biogas yields. This strategy is promising for dealing with both environmental and energy problems in spite of many challenges in the coming future.     

土壤污染的健康危害与修复技术

土壤污染是当今社会面临的重要环境问题之一,已经对人体健康构成了严重威胁。本文将土壤污染物分为有机污染物、无机污染物、生物污染物和放射性污染物,并阐述了各类污染物对人体健康的危害,介绍了具有广阔应用前景的污染土壤修复技术,即植物修复技术和微生物修复技术。最后,本文还对解决土壤污染问题提出了具体的建议。     

Effects of agronomic practices on phytoremediation of an aged PAH-contaminated soil

Phytoremediation offers an ecologically and economically attractive remediation technique for soils contaminated with polycyclic aromatic hydrocarbons (PAHs). In addition to the choice of plant species, agronomic practices may affect the efficiency of PAH phytoremediation. Inorganic nutrient amendments may stimulate plant and microbial growth, and clipping aboveground biomass might stimulate root turnover, which has been associated with increases in soil microbial populations. To assess the influence of fertilization and clipping on PAH dissipation in a nutrient-poor, aged PAH-contaminated soil, a 14-mo phytoremediation study was conducted using perennial ryegrass (Lolium perenne) as a model species. Six soil treatments were performed in replicate: unplanted; unplanted and fertilized; planted; planted and fertilized; planted and clipped; and planted, clipped, and fertilized. Plant growth, soil PAH concentrations, and the concentrations of total and PAH-degrading microorganisms were measured after 7 and 14 mo. Overall, planting (with nearly 80% reduction in total PAHs) and planting + clipping (76% reduction in total PAHs) were the most effective treatments for increased PAH dissipation after 14 mo. Fertilization greatly stimulated plant and total microbial growth, but negatively affected PAH dissipation (29% reduction in total PAHs). Furthermore, unplanted and fertilized soils revealed a similar negative impact (25% reduction) on PAH dissipation after 14 mo. Clipping did not directly affect PAH dissipation, but when combined with fertilization (61% reduction in total PAHs), appeared to mitigate the negative impact of fertilization on PAH dissipation. Therefore, fertilization and clipping may be included in phytoremediation design strategies, as their combined effect stimulates plant growth while not affecting PAH dissipation.     

Potential for enhanced phytoremediation of landfills using biosolids – a review

Despite the use of recyclable materials increasing worldwide, waste disposal to landfill remains the most common method of waste management because it is simple and relatively inexpensive. Although landfill disposal is an effective waste management system, if not managed correctly, a number of potential detrimental environmental impacts have been identified including soil and ground water contamination, leachate generation, and gas emissions. In particular, improper post-closure treatment of landfills or deterioration of the conventional clay landfill capping were shown to result in land degradation which required remediation to secure contaminants within the landfill site.Phytoremediation is an attractive technology for landfill remediation, as it can stabilize soil and simultaneously remediate landfill leachate. In addition, landfill phytoremediation systems can potentially be combined with landfill covers (Phytocapping) for hydrological control of infiltrated rainfall. However, for the successful application of any phytoremediation system, the effective establishment of appropriate, desired vegetation is critical. This is because the typically harsh and sterile nature of landfill capping soil limits the sustainable establishment of vegetation. Therefore, the physicochemical properties of landfill capping soils often need to be improved by incorporating soil amendments. Biosolids are a common soil amendment and will often meet these demanding conditions because they contain a variety of plant nutrients such as nitrogen, phosphate, potassium, as well as a large proportion of organic matter. Such amendment will also ameliorate the physical properties of the capping soils by increasing porosity, moisture content, and soil aggregation. Contaminants which potentially originate from biosolids will also be remediated by activities congruent with the establishment of plants and bacteria.     

Simulation of phytoremediation of a TNT-contaminated soil using the CTSPAC model

Knowledge of water movement in the plant-xylem system and contaminant bioavailability in the soil environment is crucial to evaluate the success of phytoremediation practices. This study investigated the removal of 2,4,6-trinitrotoluene (TNT) from a contaminated sandy soil by a single poplar (Populus fastigiata) tree through the examinations of temporal variations of xylem water potential, root water uptake, and soil TNT bioavailability. A mathematical model, CTSPAC (Coupled Transport of water, heat, and solutes in the Soil-Plant-Atmosphere Continuum), was modified for the purpose of this study. The model was calibrated using laboratory measurements before its application. Our simulations show that the xylem water potential was high in the roots and low in the leaves with a potential head difference of 3.55 cm H2O, which created a driving force for water flow and chemical transport upward from the roots through the stem to the leaves. The daily average root water uptake rate was 25 cm3 h(-1) when an equilibrium condition was reached after 24 h. Our simulations further reveal that no TNT was found in the stem and leaves and only about 1% of total TNT mass was observed in the roots due to the rapid biodegradation and transformation of TNT into its daughter products. About 13% of the soil TNT was removed by the poplar tree, resulting mainly from root uptake since TNT is a recalcitrant compound. In general, the soil TNT bioavailability decreased with time due to the depletion of soil solution TNT by the poplar tree. A constant bioavailability (i.e., 3.1 x 10(-6)) was obtained in 14 d in which the soil TNT concentration was about 10 mg L(-1). Our study suggests that CTSPAC is a useful model to simulate phytoremediation of TNT-contaminated sites.     

重金属超积累植物的研究进展

植物修复技术是治理土壤重金属污染的重要手段之一。在倡导绿色技术的今天,人们更看到了它的巨大潜力,而超积累植物则是该技术的关键。文章就超积累植物的概念、特征,修复机制,产后处置技术和开发现状作了详尽的叙述,并对今后超积累植物研究存在的问题和发展方向作了有益的探讨。     

土壤-植物系统中磷和砷相互作用关系的研究进展

砷元素导致的环境污染问题日益突出,施磷已成为植物修复砷污染土壤过程中必要强化措施之一。土壤-植物系统中磷和砷的相互作用关系是非常复杂的,研究表明：磷和砷在土壤中往往是共生的,但又存在竞争吸附关系;磷和砷在不同植物中的相互作用关系主要有拮抗效应和协同效应;有必要通过分子生物学手段对磷和砷表达基理进行深入研究,获得对砷具有超积累能力的植株。