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1.
四种浸提剂对果园与菜地土壤有效硒浸提效果的对比研究 总被引：2，自引：0，他引：2
有效硒是评价土壤中硒对植物供给能力的重要指标,我国目前尚无测试有效硒的国家标准方法。浸提剂的选择对于准确测定有效硒的含量至关重要,本文根据浸提的有效硒与硒形态的关联性来确定最优浸提剂种类。实验中选取了碳酸氢钠、磷酸二氢钾、硝酸和盐酸四种浸提剂,对天津果园和菜地的土壤进行有效硒浸提,采用原子荧光光谱法测定各形态硒的含量,并分别对浸提的有效硒与水溶态+离子交换态+碳酸盐结合态硒的最小值、25%处数据值、中位数、75%处数据值和最大值进行比较分析和差异性检验。结果表明:采用碳酸氢钠和磷酸二氢钾提取菜地土壤有效硒的平均含量均约为0.039mg/kg,高于硝酸和盐酸的提取量;采用碳酸氢钠、磷酸二氢钾、硝酸和盐酸提取果园土壤有效硒的含量依次降低。两种土壤中,磷酸二氢钾浸提有效硒的最小值、25%处数据值、中位数、75%处数据值和最大值与水溶态+离子交换态+碳酸盐结合态硒的含量最为接近,而且无显著差异性。研究认为,0.1mol/L磷酸二氢钾适合作为天津果园和菜地土壤有效硒的浸提剂。 相似文献
2.
为研究凹凸棒石-双交联水凝胶微球(SA/PVA/ATP)对镉污染土壤钝化修复的效果,将SA/PVA/ATP添加到镉浓度为3.72 mg/kg的土壤中进行淹水培育,采用模拟酸雨、二乙烯三胺五乙酸(DTPA)和三乙醇胺(TEA)混合提取剂(DTPA提取剂)提取土壤有效态镉;采用欧共体标准局顺序提取方法(BCR)提取土壤中不同形态镉;讨论了SA/PVA/ATP添加量、土壤有效态镉和各形态镉的相关性;计算了钝化容量、修复效率和重金属风险评价指数,探究了SA/PVA/ATP对土壤镉的钝化机理。结果显示,随着SA/PVA/ATP的增加,DTPA提取剂和酸雨提取的有效态镉含量分别从1.72 mg/kg和0.024 mg/kg下降到0.66 mg/kg和0.004 4 mg/kg;土壤中的弱酸可提取态镉和可还原态镉含量分别从1.40 mg/kg和0.81 mg/kg下降到1.01 mg/kg和0.41 mg/kg,而可氧化态镉和残渣态镉含量分别从0.86 mg/kg和0.63 mg/kg增加到0.95 mg/kg和1.27 mg/kg。材料添加量与土壤中有效态镉、弱酸提取态镉和可还原态镉含量呈极显著负... 相似文献
3.
土壤中铅的可溶态根据常用提取剂主要分为:弱酸可溶态、络合可溶态和盐可溶态。在研究土壤中铅的植物有效态过程中,常常采用混合提取剂来分析铅对植物有效性的相关可溶态。本文通过采用单一提取剂,计算土壤中铅的单一提取可溶态与地表植物中铅含量的线性相关系数,研究铅的弱酸可溶态、络合可溶态和盐可溶态对于地表植物有效态的线性相关性,确认铅环境影响评价过程中主要相关的形态。从实验的结果看,土壤中铅的总量、弱酸可溶态、络合可溶态和盐可溶态含量都与地表植物中铅的含量没有形成极显著的相关性。土壤中铅的弱酸可溶态与土壤表面生长植物(主要是禾草类植物的叶)中铅含量具有一定的线性相关性。而这种线性相关性受土壤的p H和土壤类型的影响而有所变化。 相似文献
4.
城市生活垃圾中重金属Cd污染修复是我国亟待解决的环境问题之一。为了确定最佳Cd污染修复技术,探究了多种镉修复技术在河道治理中的适用性。以华东地区城市河道疏浚底泥堆土修复工程为例,对重金属镉污染土壤的修复工艺进行了对比和分析。拟选定土壤稳定化修复技术、土壤淋洗技术和植物修复技术三种修复工艺对受污染土壤进行治理。实验结果表明,稳定化修复技术可以使土壤中镉的浸出率从33.3%降低到14.3%,能有效降低其在环境中的生物毒性,但镉的总量并不会降低;采用柠檬酸和草酸的土壤淋洗技术,能够使镉的去除率达到90.1%和92.4%;相比而言,植物修复技术具有更为突出的高效性、易操作和二次污染少的特点,但修复周期较长。从技术、经济、环境安全等多方面出发,分别对三种修复工艺进行了分析讨论,综合考虑了研究场地的现状和未来规划,最终确定土壤淋洗技术为治理河道底泥堆土镉污染的最佳选择。 相似文献
5.
江西丰城富硒土壤中总硒含量较高,但能被植物直接吸收利用的有效态硒含量偏低。土壤中硒的生物有效性是影响作物富硒的关键因素,寻找安全有效的改良剂对提高富硒土壤中硒的有效性至关重要。本文以生物质炭和钢渣为改良剂,共设置了8个不同处理,通过室内土培试验和盆栽实验,原子荧光光谱法测定有效态硒的含量,探究了两种改良剂在不同处理水平下对丰城富硒土壤中有效硒的调控效果。土培试验结果表明,施加不同量的生物质炭和钢渣均能提高研究区土壤pH,提升幅度为0.1～3.79个单位。元素形态分析结果表明,改良剂主要通过影响有机结合态硒来调控土壤有效态硒,施加生物质炭的土壤中有机质含量显著增加,且有机质对硒表现为固定作用,导致有效态硒含量降幅为8.4%～15.1%,使土壤有效硒含量总体偏低;而钢渣对土壤pH的显著影响有利于活化土壤中的硒元素,土壤有效态硒含量可提高1.4～2.0倍。盆栽实验结果表明,土壤经钢渣处理后小白菜硒含量提高30%以上,而经生物质炭处理后小白菜硒含量降幅在7.14%～42.8%之间。本研究认为,生物质炭不适用于调控研究区土壤中硒的有效性,钢渣可作为研究区土壤硒有效性的调控材料,既实现了固废再利用,也提高了土壤中硒的有效度。 相似文献
6.
基于小麦籽粒降Cd率及土壤Cd形态变化评价蚯蚓对Cd污染土壤的修复效果 总被引：1，自引：0，他引：1
本研究基于小麦籽粒降Cd率、土壤中Cd生物可利用态(DTPA-Cd)含量和土壤Cd移除率评价蚯蚓(赤子爱胜蚯蚓)对两种Cd污染农田土壤(河南潮土及河北褐土)的修复效果。研究结果表明：两种土壤中,添加0.5%和1.0%(蚯蚓鲜重/土壤干重)蚯蚓均能够明显降低小麦对Cd的富集,改变Cd在小麦植物器官中的分布,显著降低小麦籽粒中Cd含量(P<0.05),籽粒降Cd率达到31.1%~43.5%,促使小麦籽粒生物量增加35.5%~62.7%。添加0.5%和1.0%蚯蚓可显著降低土壤中生物可利用态Cd(DTPA-Cd)含量(P<0.05),DTPA-Cd含量下降29.1%~40.8%,有利于促进土壤中生物可利用态Cd向生物不易利用的形态转化。0.5%和1.0%蚯蚓添加使土壤中Cd移除率达到6.05%~11.88%,明显高于对照组(P<0.05),说明蚯蚓具有很好的Cd污染农田土壤修复潜力。在低Cd污染农田土壤中,蚯蚓可以降低土壤中Cd含量,减少小麦对Cd的富集,同时降低小麦籽粒Cd含量,这一研究结果对于修复低Cd污染农田土壤、保证农产品安全和实现“边生产边修复”具有重要意义。 相似文献
7.
Cd和As两种污染物的离子电荷不同,化学性质迥异,因此Cd和As复合型重金属污染的土壤修复难度大。某地农田土壤呈弱碱性,因受老旧废弃垃圾填埋场的影响变为弱酸性,土壤样品中Cd和As均超标,有效态含量高,水稻样品超标率＞15.4%。实验室小试证明:生石灰可以降低Cd的活性,升高As的有效态,综合修复效果差;活性炭和矿物“微胶囊”因其吸附机制可同时降低Cd和As的有效态含量;活性炭钝化Cd的短期效应相与矿物“微胶囊”相当,钝化As的短期效应相比矿物“微胶囊”有一定的优势;矿物“微胶囊”的长期钝化效应最好,2年观察周期后活性炭效果归零,而矿物“微胶囊”效果稳定持续,有效态去除率最终可达90%。3种材料修复Cd和As复合污染型耕地土壤的综合性能筛选结果为矿物“微胶囊”（优）＞活性炭＞生石灰（差）。 相似文献
8.
《化工矿产地质》2021,43(1)
通过向Cd污染土壤施加含不同比例生物炭、凹凸棒石、硅藻土的钝化材料,对比分析三种材料不同比例时对土壤Cd的钝化效果差异。结果表明,三种材料都能降低土壤中有效Cd的含量,随着三种材料添加比例的增加,土壤有效Cd的钝化率不断增加,空心菜Cd含量较空白样降低5.29%～57.21%,其中ATBS5%处理显著降低空心菜Cd含量,降幅达57.21%;同时钝化剂的施加减小了空心菜Cd的生物吸收系数,减少了植物对Cd吸收以及地下部分向地上可食用部分的转移,显著降低了空心菜可食用部分重金属含量。另一方面施加钝化材料均可提高作物产量,改善土壤肥力。对比三种材料修复钝化效果,ATBS 5%更适合应用于农田土壤修复。 相似文献
9.
根际环境锌镉镍的形态变化与植物有效性 总被引：1，自引：1，他引：1
以抚顺西露天采场60平盘5种修复植物根际与非根际土为研究对象，运用顺序提取实验和数理统计分析方法研究了根际与非根际土中Zn、Cd、Ni的形态分布与植物有效性。结果表明，Zn、Ni在根际与非根际土中主要以硫化物态存在；而Cd在非根际土中以硫化物态为主，在根际土中以可交换态和松、紧有机态为主。与Ni相比，非根际土中Zn的紧有机态、氧化物态和Cd的紧有机态、氧化物态、可交换态比例明显偏大；与非根际土相比，根际土中Zn的铁锰氧化物态和硫化物态含量增加，碳酸盐态含量降低，松有机态、紧有机态和可交换态Zn在不同植物根际变化不同。Cd的硫化物态降低，可交换态、松有机态、碳酸盐态、氧化物态和紧有机态含量在不同植物根际变化不同。Ni的紧有机态显著增加，可交换态、碳酸盐态和硫化物态明显降低，松有机态在不同植物根际变化不同；根际Cd的碳酸盐态增加和氧化物态降低有利于植物Cd的吸收；碳酸盐态Zn的减少可促进植物Zn的增高。 相似文献
10.
印染污泥中重金属形态分析及生物有效性 总被引：7，自引：2，他引：5
选取上海某印染厂的印染废水处理后的活性污泥样品,通过盆栽土培试验,用黑麦草对印染污泥进行修复,运用Tessier A连续提取法研究修复后黑麦草根际和非根际印染污泥中铅、铜、镍、锌、镉5种重金属形态的变化,以及重金属的生物有效性与植物中有效态含量之间的关系。结果表明,栽培后根际与非根际环境中各重金属元素具有典型的形态分布特征:铅主要以离子交换态和残渣态存在;铜主要以碳酸盐结合态和残渣态存在;镍由紧结合态(铁锰氧化物结合态+有机结合态)向离子交换态转移;锌的有机结合态和碳酸盐结合态有所增加;镉主要以离子交换态和铁锰氧化物结合态为主,说明镉元素较活泼,具有潜在的环境影响能力,应该给予更多的关注。印染污泥中重金属的生物有效性与重金属元素的性质有关,铜、锌的生物有效性较高,其次是铅,最低是镍、镉。 相似文献
11.
A. Mahar P. Wang A. Ali A. H. Lahori M. K. Awasthi Z. Wang Z. Guo Q. Wang S. Feng R. Li Z. Zhang 《International Journal of Environmental Science and Technology》2018,15(3):607-620
The immobilization of heavy metals (HMs)-contaminated soils using amendments is a cost-effective remediation technique. Therefore, the aim of this study was to evaluate the effectiveness and aging factor of CaO, fly ash (FA), sulfur, and Na2S on the immobilization of Cd, Cu, and Pb in three different contaminated soils under 1-year incubation. The study sites (S) and amendments treatments (T) are termed as S1, S2, and S3 and T1, T2, T3, and T4, respectively. The TCLP-extractable HMs were analyzed in treated soils after 2, 6, and 12 months. The higher concentrations of CaO, FA, and Na2S (T3 and T4) efficiently immobilized the Cd. However, a moderate Cd decrease was noted in sulfur-treated samples with no significant difference in ratios as compared to control in used soils. Likewise, CaO decreased moderately Cu content in used soils with gradual increase in Cu mobility. Similarly, FA, sulfur, and Na2S showed effective immobilization of Cu content with no difference in treatment ratios as compared to control. In addition, CaO, sulfur, and Na2S decreased the significant content of Pb as compared to control. However, FA treatments showed moderate reduction in Pb content with no difference in ratios. The higher concentrations of alkaline amendments should be avoided in the farmland soils as they increase the soil pH and EC of soil ecosystem. The higher ratios of alkaline amendments would be suitable to remediate the abandoned lands/brownfields. The sulfur amendment would be suitable for immobilization of metals in alkaline soils rather than in acidic soils. 相似文献
12.
《Applied Geochemistry》2005,20(2):397-408
In situ stabilization of metals in contaminated soils by addition of industrial by-products is an attractive remediation technique. In this work, mixtures of metal-spiked (Cd, Cu and Pb) samples from the Ap horizons of two acid soils and solid samples of 4 industrial by-products (red gypsum, phosphogypsum, sugar foam and dolomitic residue) were incubated in order to assess the efficiency of the by-products for the in situ remediation of contaminated soils. Single (DTPA extraction and TCLP test) and sequential chemical extraction procedures were used to examine the availability and potential mobility of the metals retained as a result of the treatments. Both the sugar foam and dolomitic residue reduced the availability and mobility of Cd, Cu and to a lesser extent, Pb. On the other hand, red gypsum and phosphogypsum proved effective in immobilizing Pb and, to a lesser extent, Cu. However, both gypsum-like by-products were not so effective in reducing Cd availability and mobility. 相似文献
13.
Mahtab Ahmad Deok Hyun Moon Kyoung Jae Lim Christopher L. Shope Sang Soo Lee Adel R. A. Usman Kwon-Rae Kim Jeong-Hun Park Seung-Oh Hur Jae E. Yang Yong Sik Ok 《Environmental Earth Sciences》2012,67(4):1023-1031
Military shooting range soils contaminated by heavy metals have been subjected to remediation efforts to alleviate the detrimental effects of exposure on humans and the surrounding environment. Waste materials can be used as cost-effective soil amendments to immobilize heavy metals in contaminated soils. In this study, naturally occurring lime-based waste materials including egg shells, oyster shells, and mussel shells were assessed for their effectiveness toward heavy metal immobilization in military shooting range soil in Korea. Soil was treated in batch leaching experiments with 0, 2.5, 5, 10, and 15% of each lime-based waste material. The results showed that the lime-based waste materials effectively reduced water-soluble Pb at an application rate of 2.5% by weight of the soil. Increase in soil pH from 6.6 to 8.0 was considered to be the main chemistry of Pb immobilization, which was supported by the formation of insoluble Pb species at high pH values as confirmed by the visual MINTEQ thermodynamic model. In contrary, water-soluble Cu was increased in the lime-based waste material-treated soils when compared to the untreated soil. This was likely attributed to the formation of soluble Cu?CDOC (dissolved organic carbon) complexes as all lime-based waste materials applied increased DOC contents in the soil. Therefore, care must be taken in selecting the appropriate amendment for immobilizing metals in shooting range soils. 相似文献
14.
Immobilization of trace elements in contaminated soils by zero-valent iron (ZVI) is a promising remediation method, but questions about its long-term performance remain unanswered. To quantify immobilization and predict possible contaminant remobilization on long timescales detailed knowledge about immobilization mechanisms is needed. This study aimed at assessing the long-term effect of ZVI amendments on dissolved copper and arsenic in contaminated soils, at exploring the immobilization mechanism(s), and at setting up a geochemical model able to estimate dissolved copper and arsenic under different scenarios. Samples from untreated and ZVI-treated plots in two field experiments where ZVI had been added 6 and 15 years ago were investigated by a combination of batch experiments, geochemical modeling and extended X-ray absorption fine structure (EXAFS) spectroscopy. Dissolved copper and arsenic concentrations were described by a multisurface geochemical model with surface complexation reactions, verified by EXAFS. The ZVI remained “reactive” after 6–15 years, i.e. the dissolved concentrations of copper and arsenic were lower in the ZVI-treated than in the untreated soils. There was a shift in copper speciation from organic matter complexes in the untreated soil to surface complexes with iron (hydr)oxides in the ZVI-treated soil. The pH value was important for copper immobilization and ZVI did not have a stabilizing effect if pH was lower than about 6. Immobilization of arsenic was slightly pH-dependent and sensitive to the competition with phosphate. If phosphate was ignored in the modeling, the dissolution of arsenate was greatly underestimated. 相似文献
15.
本研究基于小麦、玉米、高粱籽粒及烟草烟叶镉(Cd)消减率、修复边际效率及土壤中Cd有效态含量的变化等对比了实验室与田间条件下骨炭粉与海藻肥对Cd污染农田土壤的修复效果。研究结果表明：骨炭粉与海藻肥使玉米、小麦、高粱和烟草对Cd的吸收、转运均有显著(P<0.05)降低作用;在田间条件下,骨炭粉与海藻肥对不同作物籽粒或烟叶的Cd消减率为16.2%~39.8%,可增加作物产量12.3%~38.6%。钝化剂对不同作物增产效果有一定差异,对小麦籽粒增产作用最为有效。研究发现添加钝化剂改变了Cd在土壤团聚体中的分布,使得Cd在大粒径团聚体中负载量增加,并且与对照相比,显著提高土壤pH(提高0.43~0.77),降低土壤Cd的有效性,有利于控制Cd在土壤植物系统中的迁移。总体而言,不同钝化剂的Cd污染土壤修复边际效率为3.99%~14.74%,同海藻肥相比,骨炭粉的修复边际效率较高。不同钝化剂在盆栽实验的修复效果优于田间实验的效果,可能是因为相比于田间实验,盆栽实验条件下根系的作用范围有限,钝化剂的作用效果较高。 相似文献
16.
René van Herwijnen Tim Laverye Jane Poole Mark E. Hodson Tony R. Hutchings 《Applied Geochemistry》2007
Organic materials such as compost are often proposed as suitable materials for the remediation of contaminated brownfield sites intended for soft end-use. In addition to vitalising the soil, they are also believed to immobilise metals thereby breaking contaminant-receptor pathways and reducing the ecotoxicity of the contaminants. However, some research has demonstrated contradictory effects between composts on metal immobilisation. In the present study, four different composts and a liming product containing organic matter (LimeX70) were tested to examine both their metal retention and toxicity reduction capabilities on three different metal contaminated soils. Leaching tests, a plant growth test with Greek cress (Lepidium sativum), an earthworm (Eisenia fetida) survival and condition test and a bacterial toxicity test using Vibrio fischeri were carried out. The leaching test results showed that spent mushroom compost caused an increase in metal concentration in the leachates, while LimeX70 caused a decrease. The variation in behaviour between different amendments for each soil was high, so a generic conclusion could not be drawn. Toxicity tests showed significant reduction of metal bioavailability and toxicity for Greek cress, earthworms and bacteria. The results also suggest that more research should be undertaken to understand the mechanisms involved in metal complexation using different types of organic matter, in order to optimise the use of organic materials like compost for soil remediation. 相似文献
17.
A. Suda T. Makino 《International Journal of Environmental Science and Technology》2016,13(10):2375-2382
Rice consumption is considered an important arsenic source for the population in Asian countries. Previous studies showed increase in arsenic solubility in flooded soils and arsenic uptake by rice plants with the application of organic amendments, while contrasting results were also reported. Here, we comprehensively examined the effect of three types of organic amendments on arsenic solubility during long-term flooded soil incubation. The amendments examined were categorized as (1) plant-based composts, (2) cattle manures, and (3) fermented livestock (swine and poultry) droppings. The dissolved arsenic in all soils with fermented livestock dropping was significantly greater than that in control soils at 10 and 39 days after incubation. The soils with two cattle manures also contained significantly greater amounts of dissolved arsenic than control soils at day 39, while the rest of the amendments did not increase arsenic solubility. At day 80, the amount of dissolved arsenic in all soils became comparable. Tukey’s test demonstrated that the relative ratio of dissolved arsenic in soils with fermented livestock droppings to control soils was significantly greater than those with the plant-based composts and cattle manures at days 10 and 39. Furthermore, the solubilizing effect of some organic amendments was mostly explained by promotion of decrease in soil Eh, rather than increase in dissolved organic carbon. Thus, it could be concluded that fermented livestock droppings potentially have a greater risk of solubilizing As than plant-based composts and cattle manures, because of their greater ability for accelerating soil reduction, associated with their higher bio-decomposability. 相似文献
18.
Utilization of fly ash for stabilization/solidification of heavy metal contaminated soils 总被引：19，自引：0，他引：19
Pozzolanic-based stabilization/solidification (S/S) is an effective, yet economic remediation technology to immobilize heavy metals in contaminated soils and sludges. In the present study, fly ash waste materials were used along with quicklime (CaO) to immobilize lead, trivalent and hexavalent chromium present in artificially contaminated clayey sand soils. The degree of heavy metal immobilization was evaluated using the Toxicity Characteristic Leaching Procedure (TCLP) as well as controlled extraction experiments. These leaching test results along with X-ray diffraction (XRD), scanning electron microscope and energy dispersive X-ray (SEM–EDX) analyses were also implemented to elucidate the mechanisms responsible for immobilization of the heavy metals under study. Finally, the reusability of the stabilized waste forms in construction applications was also investigated by performing unconfined compressive strength and swell tests. The experimental results suggest that the controlling mechanism for both lead and hexavalent chromium immobilization is surface adsorption, whereas for trivalent chromium it is hydroxide precipitation. Addition of quicklime and fly ash to the contaminated soils effectively reduced heavy metal leachability well below the nonhazardous regulatory limits. Overall, fly ash addition increases the immobilization pH region for all heavy metals tested, and significantly improves the stress-strain properties of the treated solids, thus allowing their reuse as readily available construction materials. The only potential problem associated with this quicklime–fly ash treatment is the excessive formation of the pozzolanic product ettringite in the presence of sulfates. Ettringite, when brought in contact with water, may cause significant swelling and subsequent deterioration of the stabilized matrix. Addition of minimum amounts of barium hydroxide was shown to effectively eliminate ettringite formation. Overall, due to the presence of very high levels of heavy metal contamination along with sulfates in the solid matrices under study, the results presented herein can be applied to the management of incinerator and coal fly ash, boiler slag and flue gas desulfurization wastes. 相似文献
19.
AB-DTPA提取法在重金属污染土壤修复模拟试验中的应用可行性 总被引：2，自引：0，他引：2
将碳酸氢铵-二乙三胺五乙酸(AB-DTPA)提取重金属生物有效态的方法应用于重金属污染土壤修复的模拟试验中,该土壤的污染元素主要是铜、锌和镉,试验所用修复材料是钠化膨润土。研究表明,AB-DTPA提取法具有很好的稳定性,而且能准确指示铜、锌、镉元素在土壤中的有效态含量,同时AB-DTPA对土壤中铜、锌、镉元素的提取率也适用于模拟试验中修复效果的平行对比。AB-DTPA提取法在重金属污染土壤修复模拟试验中的应用是可行的。 相似文献