重金属污染土壤的修复方法及其在几类典型土壤修复中的应用

文中首先阐述了重金属污染土壤的途径与特点。介绍了当前几类主要的重金属污染土壤修复方法:物理化学方法、植物修复法、微生物修复法、动物修复法等的技术要点,详述了各自的技术特点及机理,并对它们的修复效能、环境友好性等进行了比较。从土壤的特性出发,区分出了3种典型的遭受重金属污染的土壤:农业土壤、城市土壤、矿区土壤,并从国内外最新的重金属污染修复实践中选取了适合各自土壤类型的修复方法进行了重金属污染土壤的治理探讨。最后,对土壤重金属污染修复技术的发展进行了展望。     

治理土壤重金属污染的方法概述

本文对近年来国内外有关治理土壤重金属污染的方法进行较为系统的归类，对各类方法的治理原理、特点、效果及应用状况进行了概述、分析，为我区土壤重金属污染的治理工作提供一定参考。     

化学改良剂对矿区重金属Pb、Cd污染土壤治理的作用

化学改良剂在治理重金属污染土壤中具有重要作用。我国许多矿区周围土壤都受到重金属污染,尤以铅、镉污染为甚,给农业生产和生态环境安全造成威胁。采用淋溶试验方法,研究不同化学改良剂在重金属Pb、Cd(Pb≤500mg/kg、Cd≤20mg/kg)污染土壤中的作用。结果表明,土壤加入化学改良剂能对重金属元素进行有效固化。研究结果为矿区重金属污染土壤的修复和安全控制方案的制定提供科学依据。     

西南某铅锌矿区土壤重金属污染现状与评价研究

为研究西南某铅锌矿区土壤重金属污染的状况,采集采矿区和尾矿区的土壤,对土壤中重金属(Zn、Pb、Cd、Cr、Cu)的水溶态、弱酸提取态和总含量进行了分析,并采用单因子污染指数法和内梅罗综合污染指数法进行了现状评价。研究得出该铅锌矿区土壤存在较为严重的重金属复合污染,重金属生物有效性和迁移能力较强,对当地生态及地下水、地表水存在严重的风险。研究成果可为铅锌矿区土壤重金属污染的监测和治理提供一定的科学依据。     

论稻田重金属污染的综合防控

概况了稻田土壤重金属污染治理的研究现状,结合修复实践,简要分析了稻田土壤重金属污染的综合防控技术,并对未来的发展方向进行了展望。     

生物炭对土壤中复合重金属的固化/稳定化研究

土壤重金属污染逐渐变成全球关注的环境问题。而固化/稳定化技术是修复重金属污染土壤快速、有效及经济的方式。概括土壤中重金属的来源和危害、固化/稳定化技术的机理,探讨了以独特物化性质的生物炭作为治理土壤中重金属的固化/稳定化剂时对重金属和砷的处理研究。最后,对未来生物炭的安全性和长期稳定性的研究作出了展望。     

韶关土壤重金属污染状况

随着工矿业的迅猛发展，韶关土壤重金属污染日益严重，直接影响到农作物的安全生产。笔者对韶关土壤重金属污染来源及其现状作了概述，并针对污染状况及其当地农作物生产的特点提出了一些治理和修复建议。     

重庆市某工业遗留地土壤重金属污染状况分析与评价

为研究土壤重金属的污染状况,从重庆市某铬污染场地土壤中采集54份样本检测分析了其Cr、Cu、Zn和Pb元素含量。结果表明:表层土壤样品中的重金属Cr、Cu、Zn、Pb的平均含量分别为3 370.8,58.0,36.1,112.4 mg/kg。该场地土壤属于重度重金属污染,潜在生态危害处于很强危害程度,各重金属的潜在生态风险指数大小顺序为:CrPbCuZn。其中,Cr的影响占绝对主导地位。研究结果可为该废弃场地的治理修复和再利用提供理论依据。     

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。     

崂山风景区土壤重金属元素环境容量的计算

崂山在青岛土壤重金属的综合污染指数排序中位于第2位，重金属污染问题比较突出。通过计算崂山风景区土壤重金属元素的静态容量和动态容量，对二者进行了比较。重金属元素环境容量的计算，可以为了解土壤承载力，实现污染物容量总量控制等提供科学依据。     

中国土壤修复与治理的投融资政策最新进展与展望

中国目前的土壤污染修复资金主要来源于政府财政性投资,融资渠道较为单一。《土壤污染防治行动计划》实施后,如何满足实现土壤污染修复与治理目标的投资需求是一个迫切需要解决的问题,充分创新发挥市场力量,建立长效的融资政策机制是核心内容。本文评估了中国土壤污染修复与治理投融资政策现状,识别了投融资面临的关键问题和挑战,提出了"十三五"时期中国土壤修复与治理的投融资机制建设的政策建议,为"十三五"时期中国土壤修复投融资模式创新提供管理技术支撑。     

Decontamination of anthracene-polluted soil through white rot fungus-induced biodegradation

This study investigated the effect of inoculation of white rot fungus, Pleurotus ostreatus, incubation time, and levels of contamination on anthracene degradation in contaminated soil over a 90-day period. Control samples were set up to compare rates of degradation at different levels of anthracene contamination in soil. Using HPLC, extracts from soil were analyzed on intervals of 30 days to determine the level of anthracene remaining in soil. After 90 days of incubation, it was observed that time, level of contamination, and fungal treatment affected the rate of degradation of all levels of anthracene contamination, inoculated soil showed more degradation of anthracene (76–89%) compared to control soil (33–51%). It was also observed that concentration of the anthracene increased at different sampling dates in some of the soil samples. In this study, such increase in anthracene concentration was attributed to errors of extraction, sorption of the anthracene to soil particles, and possible repolymerization of anthracene in soil organic matter. The release of ligninolytic enzymes such as lignin peroxidase, laccase, and manganese peroxidase by Pleurotus ostreatus was associated with the anthracene degradation observed. A general observation indicates that an interaction between time, level of contamination, and soil treatment is vital in the degradation of high levels of anthracene contamination by the white rot fungus.     

Bioremediation of cutting fluids contaminated soil by Pleurotus tuber-regium Singer

This study investigated the effect of inoculation of Pleurotus tuber-regium, a Nigerian white rot fungus, period of incubation, different levels of contamination on cutting fluids degradation in contaminated soil over 30, 60, and 90 days. Control for different levels of cutting fluids was also used to compare rates of bioremediation of the contaminant in the soil. At the end of each incubation period, the mycelia-ramified substrate was separated from the soil layer and dried. The soil samples were analyzed for physico-chemical parameters; total petroleum hydrocarbon, lignin content by determining the acid detergent fraction (ADF), heavy metals content of the soil using flame atomic absorption spectrophotometer, and changes in the polyphenol oxidase and peroxidase activities were also determined after 1, 2, and 3 months. P. tuber-regium improved the nutrient status of the soil and increased enzyme activity was recorded. A reduction in the pH and heavy metal contents of the soil at all levels of cutting fluids concentrations was detected. The lignin in the rice straw decreased from 34.50% in the control to 8.06% at 30% cutting fluids concentration after 3 months of incubation. The highest TPH loss of 30.84% was recorded at 20% cutting fluids contamination after 3 months compared to 13.75% at the onset of the experiment. The improvement of the nutrient contents of the soil, bioaccumulation of heavy metals, degradation of TPH, lignin, and increased activity of polyphenol oxidase and peroxidase was due to biodegradation of the cutting fluids.     

Ecotoxic effect of phenanthrene on nitrifying bacteria in soils of different properties

Information on ecotoxicity of organic contaminants, such as polycyclic aromatic hydrocarbons (PAHs), in terrestrial environment is needed for establishing soil quality criteria and for risk assessment purposes. An ecotoxic effect of a model PAH compound (phenanthrene) toward soils microorganisms (nitrifying bacteria) was evaluated in 50 different soils. The soil samples were collected from agricultural land in four regions of Poland with varying levels of industrialization (Slaskie, Dolnoslaskie, Podlaskie, and Lubelskie voievodeships). Soils were characterized for basic physicochemical properties (texture, organic matter content, pH(KCl), total nitrogen content, total sorption capacity) and the content of contaminants including PAHs (73-800 microg kg(-1)), Pb (6-720 mg kg(-1)), and Zn (9-667 mg kg(-1)). Ecotoxicity of phenanthrene (applied at 10, 100, 500, and 1000 mg kg(-1)) to soils microorganisms was evaluated in laboratory studies in control conditions (incubation of soils for 7 d at 20 +/- 2 degrees C). Nitrification potential was used as the ecotoxicity measurements end point. The EC50 values (146-1670 mg kg(-1)) calculated from the square root-X linear regression model differed significantly in various soils, although it was difficult to establish a causative relationship between soil physicochemical characteristic and phenanthrene toxicity. A significant factor in the assessment of soils vulnerability to the effect of phenanthrene was level of soil contamination, particularly with PAHs. Soils with previous contamination were more susceptible (mean EC50, 325 mg kg(-1)) than soils from uncontaminated, rural areas (mean EC50, 603 mg kg(-1)).     

Soil,water and plants contamination by total chrome and chrome VI

The chrome (Cr) is a metal utilized in various industrial sectors and its investigation in the environment is necessary, for the Cr (III) contain aessential micronutrients in the human nourishment and the Cr (VI), on the other hand, is toxic. In the present work soil contamination with Cr was realized in drainagelysimetersset in concentrations of 0, 200, 400, 600, 800 and 1000 mg kg⁻¹ of total Cr, with the intuition to determine the total Cr and Cr (VI) flux in leached water, in soil and in plants of lettuce (Lactuca sativa L.). In the lysimeters were cultivated four plants, in three cultivation circles. In the end of the cultivations was observed, that the total applied Cr leached in the soil, evidencing the Cr mobility in latossoil with simulant characteristics to the ones utilized in this paper. The Cr (VI) concentrations in the soil increased soon after the treatment applications, but tend to decrees in the time elapse, the same tendences were observed for the total Cr concentrations in the leached water. The Cr absorption by plants was related to the Cr disponibility in the soil, for the soil concentration and the plants decreased with time passing. The Cr mobility in the soil possibilitated the groundwater contamination presenting risks to the water quality and, consequently to public health.     

Relationship between water repellency and native and petroleum-derived organic carbon in soils

Some soils develop severe and persistent water repellency following contamination with crude oil. This study was conducted to characterize and compare the spatial distribution of soil water repellency and residual oil contamination at 12 such sites. The molarity of ethanol droplet (MED) test was used to assess soil water repellency and the content of dichloromethane-extractable organics (DEO) was used to quantify residual oil in soil. We found a relatively strong positive correlation between MED and DEO in soil (r2 = 0.74). Both variables tended to decrease abruptly with depth at 11 of the 12 study sites. Dichloromethane-extractable organics similarly decreased with depth in control adjacent soil (MED = 0 M), but from an average concentration one to two orders of magnitude lower than in water-repellent soil. Using data from corresponding control adjacent and water-repellent soils, we determined that approximately 29 and 10% of measured total organic carbon in water-repellent A- and B-horizon soil, respectively, consists of dichloromethane-insoluble organic carbon of petroleum origin. We propose that this fraction contains most of the causative agents of soil water repellency at the studied sites.     

甘肃省土壤污染防治制度构建

甘肃省土壤污染主要表现在农村面源污染、工业区城市污染以及矿区污染三个方面。究其原因，与甘肃省地理环境、社会经济发展有密切的联系；而从制度的角度看，甘肃省土壤污染只是作为全国土壤污染防治缺陷的一个缩影，有其必然性和特殊性。立足甘肃土壤污染实际情况，分析其产生的原因，最后对甘肃省土壤污染防治的制度构建提出相应建议。     

Sources, sinks, and exposure pathways of lead in urban garden soil

The chemistry of Pb in urban soil must be understood in order to limit human exposure to Pb in soil and produce and to implement remediation schemes. In inner-city gardens where Pb contamination is prevalent and financial resources are limited, it is critical to identify the variables that control Pb bioavailability. Field-portable X-ray fluorescence was used to measure Pb in 103 urban gardens in Roxbury and Dorchester, MA, and 88% were found to contain Pb above the USEPA reportable limit of 400 mug g(-1). Phosphorus, iron, loss on ignition, and pH data were collected, Pb-bearing phases were identified by X-ray diffraction, and Pb isotopes were measured using inductively coupled plasma mass spectrometry. Four test crops were grown both in situ and in Roxbury soil in a greenhouse, and plant tissue was analyzed for Pb uptake by polarized energy-dispersive X-ray fluorescence. Variation at the neighborhood scale in soil mineralogical and chemical characteristics suggests that the bioavailable fraction of Pb in gardens is site specific. Based on Pb isotope analysis, two historical Pb sources appear to dominate the inventory of Pb in Roxbury gardens: leaded gasoline ((207) Pb/(206) Pb = 0.827) and Pb-based paint ((207)Pb/(206) Pb = 0.867). Nearly 70% of the samples analyzed can be isotopically described by mixing these two end members, with Pb-based paint contributing 40 to 80% of the mass balance. A simplified urban human exposure model suggests that the consumption of produce from urban gardens is equivalent to approximately 10 to 25% of children's daily exposure from tap water. Furthermore, analysis of over 60 samples of plant tissue from the four test species suggests that in these urban gardens unamended phytoremediation is an inadequate tool for decreasing soil Pb.     

土壤酞酸酯测定的污染干扰及控制措施

本文针对土壤酞酸酯测定过程中不同阶段(如采样、分析样品制备、仪器分析、空白样检测)的污染干扰,提出了对应的污染控制措施,以降低测定过程中的污染风险,保证测定结果的准确性、可靠性。     

Remediation technologies for heavy metal contaminated groundwater

The contamination of groundwater by heavy metal, originating either from natural soil sources or from anthropogenic sources is a matter of utmost concern to the public health. Remediation of contaminated groundwater is of highest priority since billions of people all over the world use it for drinking purpose. In this paper, thirty five approaches for groundwater treatment have been reviewed and classified under three large categories viz chemical, biochemical/biological/biosorption and physico-chemical treatment processes. Comparison tables have been provided at the end of each process for a better understanding of each category. Selection of a suitable technology for contamination remediation at a particular site is one of the most challenging job due to extremely complex soil chemistry and aquifer characteristics and no thumb-rule can be suggested regarding this issue. In the past decade, iron based technologies, microbial remediation, biological sulphate reduction and various adsorbents played versatile and efficient remediation roles. Keeping the sustainability issues and environmental ethics in mind, the technologies encompassing natural chemistry, bioremediation and biosorption are recommended to be adopted in appropriate cases. In many places, two or more techniques can work synergistically for better results. Processes such as chelate extraction and chemical soil washings are advisable only for recovery of valuable metals in highly contaminated industrial sites depending on economical feasibility.