共查询到20条相似文献，搜索用时 171 毫秒
1.
采用温室盆栽试验,以无芒雀麦(W)为修复植物,研究淀粉(D)不同剂量与无芒雀麦组合对煤矿区多环芳烃(PAHs)长期污染农田土壤修复的影响。结果表明,在土壤中添加淀粉剂量D1、D2培养3个月后,显著促进了土著微生物对煤矿区长期污染农田土壤PAHs的降解。D1、D2处理土壤中16种PAHs总量降解率(16.82%,19.06%)分别比对照CK(11.12%)提高了51.26%和71.40%,尤其对6环PAHs的降解增效最为突出。D2处理对6环PAHs的降解达最高,为37.05%,比CK处理提高了241.01%,且为D1处理的1.77倍。在污染土壤中添加淀粉并种植无芒雀麦(D1+W,D2+W)后,与对照CK、淀粉(D)和种植无芒雀麦单一处理(W)相比,土壤中16种PAHs总量降解率有了明显增加,D1+W与D2+W处理下16种PAHs降解率分别为26.26%和28.39%;在PAHs不同环数中对5,6环PAHs的修复效果提升最为明显,对其它环数PAHs降解效果提升不显著,其中5环和6环PAHs降解率在D2+W组合处理下达到最高,为48.63%和58.32%,比CK处理提高了110.36%和436.82%,比无芒雀麦单一处理提高了27.50%和47.77%。从土壤酶活性角度,淀粉、无芒雀麦单一处理及其组合下的土壤过氧化氢酶活性差异不明显,但均显著高于对照CK处理;无芒雀麦对多酚氧化酶活性有明显的激活作用,且与淀粉组合进一步显著提升了该酶的活性,与D1+W与D2+W组合下的5,6环PAHs降解率达最高相一致。综上,利用淀粉与无芒雀麦的优化组合形式能明显提升煤矿区5,6环PAHs长期污染农田土壤的修复效果,可以作为该区污染土壤修复治理的一种选择。 相似文献
2.
H_2O_2分次投加可以提高石油烃(total petroleum hydrocarbons,TPH)去除率,本试验选用900 mmol/L H_2O_2分3次投加的方式进行分级Fenton氧化修复长链原油污染土壤。在Fe~(2+)、固相铁、Fe~(2+)+盐酸羟胺、固相铁+盐酸羟胺4种催化体系下进行试验,发现在向Fe~(2+)体系和固相铁体系加入盐酸羟胺后,后两级反应·OH强度明显增强,是未加入盐酸羟胺体系下的3倍～4倍,TPH及长链烃氧化量也大幅提高。采用向Fenton体系中加入盐酸羟胺的方式,克服了分级Fenton氧化过程中由于Fe~(2+)不足导致·OH强度较第一级显著降低、TPH及长链烃氧化量大幅下降的缺陷,促进了后两级反应过程中·OH的产生,从而大大提高了后两级TPH及长链烃的去除效果,使后两级去除效果与第一级接近,能够维持在较高水平,为急需短时间进行的土壤修复提供了一定的理论依据。 相似文献
3.
几种豆科、禾本科植物对多环芳烃复合污染土壤的修复 总被引：3，自引：0，他引：3
通过盆栽试验,研究了几种豆科植物与禾本科植物对多环芳烃(PAHs)复合污染土壤的修复作用。结果显示,90天后8种植物对土壤中PAHs均有不同程度降解效果,其中紫花苜蓿和多年生黑麦草对土壤PAHs的去除率分别达48.4%、46.8%,且对3环PAHs去除较为彻底,对4环及4环以上的PAHs去除效果较差。8种供试植物对PAHs均有一定的吸收、富集与转运的能力,紫花苜蓿和多年生黑麦草对土壤PAHs的生物富集系数分别为0.096、0.085,其提取修复效率为0.017%和0.013%。可见,紫花苜蓿和多年生黑麦草具有较好的根际修复潜力。 相似文献
4.
多环芳烃污染土壤的植物-微生物联合修复初探 总被引：4，自引：1，他引：3
在温室盆栽条件下,通过种植紫花苜蓿单独或联合接种菌根真菌(Glomus caledonium L.)(AM)和多环芳烃专性降解菌(DB),研究了利用植物-微生物强化修复多环芳烃(PAHs)长期污染土壤的效果。试验结果表明,接种菌根真菌和PAHs专性降解菌能促进紫花苜蓿的生长和土壤中PAHs的降解。经过90天修复试验,种植紫花苜蓿接种AM、DB和DB+AM处理的PAHs的降解率分别为47.9%、49.6%、60.1%,均高于只种植紫花苜蓿的对照处理(CK)(21.7%)。另外,随着PAHs苯环数的增加,其平均降解率逐渐降低,但是接种PAHs专性降解菌能够提高4环和5环PAHs的降解率。同时也发现土壤中脱氢酶活性和PAHs降解菌数量越高的处理,土壤PAHs的降解率也越高,这也是种植紫花苜蓿接种微生物能够有效促进土壤PAHs降解的原因。 相似文献
5.
生物表面活性剂强化微生物修复多环芳烃污染土壤的初探 总被引：8，自引：0，他引：8
通过温室盆栽实验,单独或联合接种多环芳烃专性降解菌(DB)和添加生物表面活性剂-鼠李糖脂(RH),研究了生物表面活性剂强化微生物修复多环芳烃(PAHs)长期污染土壤的效果。结果表明,添加RH和接种DB能明显促进土壤中PAHs总量和各组分PAHs的降解。经过90 d培养后,添加RH、DB和RH+DB处理的PAHs的降解率分别为21.3%、32.6%、36.0%,较对照分别提高了333.0%、563.3%、633.0%。此外,随着苯环数的增加,土壤中15种PAHs平均降解率逐渐降低。同时也发现DB、RH+DB处理土壤中脱氢酶活性、多酚氧化酶活性和PAHs降解菌数量显著高于CK、RH处理,但是CK与RH处理没有显著差异,说明DB、RH在促进土壤中PAHs的降解方面有不同的机制。 相似文献
6.
采用温室盆栽试验,在种植紫花苜蓿的同时,分别施加木霉菌剂、根瘤菌菌剂以及木霉与根瘤菌复合菌剂,并采用离心分级法将处理后土壤分为4个粒径团聚体,即细黏粒(0.1~1μm)、粗黏粒(1~5μm)、粉粒(5~50μm)以及细砂粒(50~250μm),分析了植物–微生物联合作用对不同粒径土壤中PAHs的去除效应。研究结果表明:紫花苜蓿–根瘤菌联合作用对PAHs污染土壤的修复效果最优,其降解率达60%以上。不同粒径组分中PAHs含量的分布表现为细砂粒粉粒粗黏粒细黏粒,且PAHs在不同粒径团聚体中去除率差异性较大。低环(2、3环)PAHs在各粒径组分中去除率较低(20%以下),并在不同粒径组分间呈非均衡分配状态;4环PAHs的去除主要集中在粉粒和细砂粒中,而5环PAHs的去除主要发生在细黏粒上。可见,PAHs在土壤不同粒径组分中分布特征及降解效应为进一步阐明PAHs污染土壤的生物修复机制提供了科学依据。 相似文献
7.
一株副球菌对污染土壤中多环芳烃的降解研究 总被引：5，自引：1，他引：4
从受多环芳烃(PAHs)长期污染的土壤中分离到一株降解PAHs的噬氨副球菌(Paracoccus aminovorans)HPD-2.使用HPD-2的菌液对PAHs污染的土壤进行了2周的生物降解试验,结果表明加入HPD-2能够明显提高土壤中PAHs的降解率.加菌土壤中PAHs的总去除率为22.9%,PAHs各组分的降解率在19.5% ～ 36.2% 之间.其中三环PAHs的降解率最高(36.1%),五环次之(26.0%),四环的最低(20.9%).对土壤微生物的计数结果发现,HPD-2的加入显著提高了土壤中细菌的数量,而对放线菌和真菌的影响不明显.PCR-DGGE分析结果表明,降解过程中HPD-2可能成为土壤中的优势菌.以上结果表明该菌株在PAHs污染土壤的生物降解中具有较好的应用前景. 相似文献
8.
9.
以2年生香樟幼苗为材料,采用不同浓度Na HCO_3和Na_2CO_3(1︰1)混合溶液(0、50、100、200、300 mmol/L)处理,研究香樟幼苗对Fe~(2+)、Mg~(2+)、K~+、Na~+的吸收和分配。结果表明:随盐碱胁迫程度的增加,香樟幼苗根系和茎器官中的K~+含量呈下降趋势,而叶片中的K~+含量呈逐步上升趋势,其中叶片中的K~+含量最高,其次是根系,茎器官中的K~+含量最低;香樟幼苗根系、茎、叶片中的Na~+含量呈逐步上升趋势,其中根系中的Na~+含量最高,其次是叶片,茎器官中的Na~+含量最低;香樟幼苗根系、茎、叶片中的K~+/Na~+呈逐步下降趋势,其中茎器官中的K~+/Na~+最高,其次是叶片,根系中的K~+/Na~+最低。低盐碱胁迫(0~100 mmol/L)提高根、茎、叶器官中Fe~(2+)的含量,提高香樟叶片中叶绿素a、叶绿素b和总叶绿素的含量;而高盐碱胁迫(100~300 mmol/L)则降低根器官中Fe~(2+)的含量,增加茎、叶器官中Fe~(2+)的含量,明显降低叶绿素a、叶绿素b和总叶绿素的含量,根器官中Fe~(2+)的含量最高,其次是茎器官,叶器官中Fe~(2+)的含量最低。盐碱胁迫对香樟幼苗根、茎、叶器官中Mg~(2+)的含量影响差异不显著。盐碱胁迫初期,香樟幼苗通过将Na~+截留在根部,促进根器官对K~+、Fe~(2+)等营养元素的吸收和转运,提高自身对低盐碱胁迫(0~100 mmol/L)的耐受性;高盐碱胁迫(100~300 mmol/L)严重影响香樟幼苗对K~+、Fe~(2+)等营养元素的吸收和转运,影响香樟正常生长发育。 相似文献
10.
多环芳烃污染土壤生物联合强化修复研究进展 总被引：10，自引：1，他引：9
多环芳烃(polycyclic aromatic hydrocarbons,PAHs)是广泛存在于环境中的一类有毒有机污染物。在PAHs污染土壤修复领域中,运用一些生物化学的方式来强化生物联合修复技术可以有效缩短生物修复的时间,大大提高修复效率,最具发展前景和应用价值。本文主要以植物-微生物、植物-微生物-土壤动物两种生物联合修复方式为对象,结合各自的特点、机理和实例,推断了其修复机制的内在原因,总结了影响土壤中PAHs降解效率的主要因素(包括:PAHs的浓度水平、根系分泌物的种类、外源添加降解菌和土壤动物的数量和种类、菌属或土壤动物之间的种间竞争和部分环境因素等);同时通过综述近年来国内外强化生物联合修复PAHs污染土壤的技术原理、应用成果和存在的一些问题,指出了不同情况下制约PAHs强化降解进程的潜在限制因子(包括:表面活性剂和固定化微生物的添加量、不同表面活性剂的适度混合、载体材料的性质、固定化方式的选取、土壤养分和水分含量等);并强调在进行强化修复的过程中,要注重现场应用和安全性评价,为多环芳烃污染土壤的生物联合强化修复研究提供了理论依据和技术参考。 相似文献
11.
自20世纪60年代"绿色革命"以来,育种技术和农耕技术的发展促进了农作物产量的大幅提升,然而作物的营养品质出现下降趋势。在相似的遗传背景下,大气CO_2浓度升高会使单位体积农作物产品的营养元素含量下降,因此"绿色革命"至今,农作物产品的营养元素下降可能受大气CO_2浓度升高影响。通过植物生长箱模拟"绿色革命"初期和目前的大气CO_2浓度水平(310μmol/mol和400μmol/mol),针对主要C_3作物水稻、小麦和大豆,研究"绿色革命"以来大气CO_2浓度升高对其籽粒的C、N、Fe、Zn元素含量的影响,结果表明:CO_2浓度升高对3种作物籽粒的C元素含量几乎没有影响,变化幅度在±1.5%之间;籽粒的N、Fe、Zn元素含量普遍呈现下降趋势,但均未达到显著水平。 相似文献
12.
氮肥及黄腐酸对盐渍土有机碳和团聚体特征的调控作用 总被引：2，自引：0，他引：2
为了探明不同氮肥水平下黄腐酸对盐碱障碍土壤的改良及培肥效应,本研究以滨海滩涂新垦轻中度盐碱障碍土壤为研究对象开展田间试验,采用水稻-小麦轮作种植模式,通过测定土壤电导率、pH、有机碳和土壤团聚体含量及其稳定性,研究黄腐酸与不同氮肥水平对土壤盐分消减调控和土壤地力提升效应。结果表明:黄腐酸能有效降低耕层土壤盐分,在氮水平300 kg/hm~2条件下黄腐酸处理对耕层0～20 cm土壤电导率与p H降低效果最好;黄腐酸可以有效改善土壤结构及稳定性,小麦季与水稻季,在氮水平300kg/hm~2条件下黄腐酸处理土壤2mm水稳性大团聚体含量相较于不施肥对照分别增加18.6%和13.8%,土壤团聚体平均重量直径与当地常规施肥相比增加38%;围垦初期,氮水平处理相较于黄腐酸处理对耕层土壤有机碳含量的影响更大,氮水平300kg/hm~2处理相较于低氮(225kg/hm~2)与高氮(325kg/hm~2)处理,两季土壤总有机碳积累量分别增加31.0%和120.0%。综合考虑土壤改良效应,黄腐酸处理土壤表层盐分降低、水稳性大团聚体含量增加且稳定性增强、有机碳含量提升,因此黄腐酸结合适宜用量氮肥是一条轻中度盐碱障碍土壤的优化施肥措施。 相似文献
13.
Bert van Bavel 《Journal of Soils and Sediments》2006,6(4):208-214
Background, Aim and Scope
Polycyclic aromatic hydrocarbons (PAHs) are formed as a result of incomplete combustion and are among the most frequently
occurring contaminants in soils and sediments. PAHs are of great environmental concern due to their ubiquitous nature and
toxicological properties. Consequently, extensive research has been conducted into the development of methods to remediate
soils contaminated with PAHs. Fenton's reagent or ozone is the most commonly studied chemical oxidation methods. However,
the majority of remediation studies use soils that have been artificially contaminated with either one or a limited number
of PAH compounds in the laboratory. Hence, it is essential to extend such studies to soils contaminated with multiple PAHs
under field conditions.
Objectives The objective of this study is to investigate the capacity of Fenton's reagent and ozone to degrade PAHs in soils. The soils
have been collected from a number of different industrial sites and, therefore, will have been exposed to different PAH compounds
in varying concentrations over a range of time periods. The capacity of Fenton's reagent and ozone to degrade PAHs in industrially
contaminated soils is compared to results obtained in studies using soils artificially contaminated with PAHs in the laboratory.
Materials and Methods:
Nine soil samples, contaminated with PAHs, were collected from five different industrial sites in Sweden. For the Fenton's
reagent procedure, the pH of the soil slurry samples was adjusted to pH 3 and they were kept at a constant temperature of
70oC whilst H2O2 was added. For the ozone procedure, soil samples were mixed with 50% water and 50% ethanol and kept at a
constant temperature of 45 oC. Ozone was then continually introduced to each soil sample over a period of four hours. Following
the Fenton's reagent and ozone oxidation procedures, the samples were filtered to isolate the solid phase, which was then
extracted using pressurized liquid extraction (PLE). The sample extracts were cleaned up using open columns and then analysed
by gas chromatography-mass spectrometry (GC-MS).
Results:
The relative abundance of the detected PAHs varied between soils, associated with different industries. For example, low molecular
weight (LMW) PAHs were more abundant in soil samples collected from wood impregnation sites and high overall PAH degradation
efficiencies were observed in soils originating from these sites. In the contaminated soils studied, PAHs were more effectively
degraded using Fenton's reagent (PAH degradation efficiency of 40-86%) as opposed to ozone (PAH degradation efficiency of
10-70%). LMW PAHs were more efficiently degraded, using ozone as the oxidizing agent, whereas the use of Fenton's reagent
resulted in a more even degradation pattern for PAHs with two through six fused aromatic rings.
Discussion:
The degradation efficiency for both methods was largely dependent on the initial PAH concentration in the soil sample, with
higher degradation observed in highly polluted soils. LMW PAHs are more susceptible to degradation than high molecular weight
(HMW) PAHs. As a result of this the relative abundance of large (often carcinogenic) PAHs increased after chemical oxidation
treatment, particularly after ozone treatment. Repeated Fenton's reagent treatment did not result in any further degradation
of soil PAHs, indicating that residual soil PAHs are strongly sorbed. The effectiveness of the two oxidation treatment approaches
differed between industrial sites, thus highlighting the importance of further research into the influence of soil properties
on the sorption capacity of PAHs.
Conclusions:
This study demonstrates that the degree to which chemical oxidation techniques can degrade soil bound PAHs chemical degradation
is highly dependent on both the concentration of PAHs in the soils and the compounds present, i.e. the various PAH profiles.
Therefore, similarities in the PAH degradation efficiencies in the nine soil samples studied were observed with the two chemical
oxidation methods used. However, the degradation performance of Fenton's reagent and ozone differed between the two methods.
Overall, Fenton's reagent achieved the highest total PAH degradation due to stronger oxidation conditions. LMW PAHs showed
higher susceptibility to oxidation, whereas high molecular weight (HMW) PAHs appear to be strongly sorbed to the soils and
therefore less chemically available for oxidation. This study highlights the importance of including soils collected from
a range of contaminated sites in remediation studies. Such soil samples will contain PAH contaminants of varying concentrations,
chemical and physical properties, and have been aged under field conditions. In addition to the chemical and physical properties
of the soils, these factors will all influence the chemical availability of PAHs to oxidation.
Recommendations and Perspectives:
We recommend including aged contaminated soils in chemical degradation studies. In future chemical remediation work, we intend
to investigate the potential influence of the chemical and physical properties of PAHs and soil parameters potential influence
on the chemical oxidation efficiency in aged contaminated soils.
Due to the vast number of contaminated sites there is a great need of efficient remediation methods throughout the world.
This study shows the difficulties which may be experienced when applying remediation methods to a variation of contaminated
sites. 相似文献
14.
Marco Derudi Gianluca Venturini Giorgio Lombardi Giuseppe Nano Renato Rota 《European Journal of Soil Biology》2007,43(5-6):297
The effectiveness of the SS-SBR (Soil Slurry – Sequencing Batch Reactor) process for the remediation of soils contaminated by several organic pollutants has been evaluated. Experimental tests have been performed on two different soils, a spiked one and an industrial aged soil. The spiked soil, artificially contaminated, has been prepared trying to simulate the pollution of an industrial aged soil in terms of number and kind of contaminants. PAHs (Polycyclic Aromatic Hydrocarbons) and phenols degradation has been particularly investigated because they are considered persistent and recalcitrant. Concerning the spiked soil, removal efficiencies higher than 95% in 6 to 9 weeks have been found for all the pollutants, except for five-rings PAHs; however, these compounds were partly removed in 11 to 13 weeks. Good results have been achieved also for the industrial aged soil with a maximum removal of about 80% in 7–8 weeks. To enhance the pollutants degradation, trying to obtain a faster remediation, the biological treatment has been combined with a chemical oxidation with ozone. The best degradation effectiveness of the combined process has been obtained applying the ozonation after few days of the biological treatment. Therefore, a combined biological and chemical treatment allowed to markedly improve the remediation of contaminated soils. 相似文献
15.
不同类型表面活性剂增效去除焦化厂污染土壤中多环芳烃的研究 总被引：3，自引：0，他引：3
Surfactant enhanced remediation is thought to be an effective method for the remediation of soils polluted with hydrophoblc organic compounds. Desorption of polycyclic aromatic hydrocarbons （PAHs） from an abandoned manufactured gas plant （MGP） soil was evaluated using four eluting agents including Triton X-100 （TX100）, sodium dodecylbenzene sulfonate （SDBS）, rhamnolipid water solution （RWS） and rhamnolipid fermentation broth （RFB）. The weight solubilization ratios for acenaphthene and fluorene were in the order of TX100 〉 SDBS 〉 RWS 〉 RFB. The Sm value, which indicates the maximum amounts of surfactants adsorbed in the soil, was in the order of RWS 〉 RFB 〉 SDBS 〉 TX100. By using 8 g L-1 of TX100, SDBS and RWS and 100% of RFB, the T-PAHs removal for the MGP soil contaminated with 207.86 mg T-PAHs kg-1 dry soil was 48.0%, 45.7%, 1.9%, and 8.6%, respectively, while that decreased to 41.6%, 37%, 0.38%, and 1.3% for the soil contaminated with 3494.78 mg T-PAHs kg-1 dry soil. Only 8 g L-1 TX100 could remove all types of the 16 PAHs partly in the MGP soil, and the removal efficiencies of different PAHs ranged from 13% to 77.8%. The results of this study herein provide valuable information for the selection of TX100 surfactant for remediating PAH-contaminated soils in MGP. 相似文献
16.
Purpose
Polycyclic aromatic hydrocarbons (PAHs) are hydrophobic organic pollutants of great environmental and health concern. PAHs are very persisted in soils and sediments which make it very difficult to remove them from soil. Therefore, remediation of PAH-contaminated sites has become an important environmental issue. The objective of this work was to study PAH degradation by pulsed corona discharge plasma system.Materials and methods
Phenanthrene (Phe) was used as the model pollutant. The Phe-contaminated soil samples were prepared by adding appropriate amount of Phe dichlormethane solution (200 mg/L) into a given amount of pretreated soil, and Phe distributed uniformly in the soil at about 100 mg/kg. The experimental system mainly consisted of a pulse high-voltage power supply and a reactor vessel. The high-voltage electrode comprised of six stainless-steel needles and the ground electrode was a stainless-steel plate. The concentration of Phe was determined by HPLC system after being extracted out from soil. Effect of run parameters such as pulse voltage, pulse frequency, air flow rate, gas atmosphere, and initial concentration of Phe on Phe degradation was investigated, and the consumption of ozone during discharge process was also studied.Results and discussion
The results showed that degradation efficiency of Phe (initial concentration 100 mg/kg) approached approximately 70 % after 40 min of discharge treatment under the conditions of pulse voltage 18 kV, pulse frequency 70 Hz, and air flow rate 0.8 L/min, which increased with the pulse voltage and pulse frequency due to the enhancement of input energy. An optimal air flow rate of 0.8 L/min was observed to obtain a maximum Phe degradation efficiency. Oxygen atmosphere favored Phe degradation due to high concentration of generated O-reagents, and ozone was found to act on Phe degradation. The concentration of Phe had influence on remediation capacity that increased with the amount of Phe in soil.Conclusions
The results confirmed that pulsed corona-discharge plasma was a potential method for remediation of PAH-contaminated soil. This study offered a viable treatment option for remediation of Phe-contaminated soil, which was expected to remove PAHs other than Phe from soil with further development.17.
Javed Iqbal Caroline Metosh-Dickey Ralph J. Portier 《Journal of Soils and Sediments》2007,7(3):153-158
Goal, Scope and Background Temperature and soil moisture content are important environmental variables in bioremediation technologies. Optimizing these
variables in-situ would enhance and maintain remediation of hazardous wastes during cold winter seasons or in cold regions and may lead to
reduced maintenance and/or cost. The effect of elevated temperature and soil moisture on bioremediation efficiency was investigated
using a laboratory mesocosm approach. Selected polycyclic aromatic hydrocarbons (PAHs) and phenols degradation in contaminated
flooded soils, commonly found in Superfund sites situated in coastal plains sediments/soils, were evaluated in the mesocosms.
Material and Methods Four laboratory mesocosm treatments in triplicate simulating in-situ bioremediation of contaminated site soils using an immobilized microbe bioreactor system, i.e., bioplug, were established
to evaluate temperature effects. Elevated temperature treatments of site soils with and without contaminant-specific microorganisms
were established at a temperature of 42±2°C. Similarly, treatment of site soils with and without contaminant-specific microorganisms
were established at an ambient temperature of 21±1°C. Composite samples were analyzed for selected PAHs and chlorinated phenols
to determine rates of mineralization and overall remediation efficiency for different temperature regimes.
Results Mesocosm studies indicated that the high temperature inoculated treatment demonstrated a significant reduction in mean total
PAHs and total phenols with a kinetic rate (KR) of 76±13 ng g−1 d−1 in 49 days (approximately 84% reduction; p<0.01) The KR for low temperature inoculated treatment was 54±1 ng g−1 d−1 in 49 days (approximately 66% reduction; p<0.01). High temperature non-inoculated mesocosms exhibited significant mineralization
of all constituents with KR of 15±6 ng g−1 d−1 (approximately 65% reduction; p<0.01) in 49d compared to 54% reduction for low temperature non-inoculated treatment with
KR of 12±3 ng g−1 d−1 (p=0.1794). Phenol compounds in inoculated treatments were also significantly reduced (65%, p<0.01) at elevated temperatures
compared to ambient (52%, p<0.01).
Discussion Increased bioavailability and desorption were noted for elevated temperature and moisture in the soil laboratory mesocosms
simulating a field in situ remediation protocol. This protocol employing the application of immobilized microflora indicated that in situ systems provide an economical advantage if optimal elevated temperature and moisture are controlled properly. Results also
suggested that temperature and moisture optimization needs to be combined with efficient nutrients delivery systems for impacted
soils/sediments.
Conclusions The study demonstrated that temperature and soil moisture contents are important factors in the success of in-situ bioremediation techniques at hazardous waste sites situated in a coastal zone. Kinetic rates were significantly enhanced
to remediate known recalcitrant compounds (PAHs and phenols) in aged soil.
Recommendations and Perspectives The placement of a preferred microbial consortia such as an immobilized microbial population in an entrained bioreactor, i.e.,
bioplug, can significantly reduce constituents of concern in a timely manner for contaminated soils/sediments. However, frequent
monitoring of the soil temperature, moisture content, nutrient level, and dissolved oxygen is necessary to achieve predictable
kinetic rates of mineralization.
ESS-Submission Editor: Dr. Teresa Cutright (tcutright@uakron.edu) 相似文献
18.
Toshiyuki Wakatsuki Hisao Furukawa Keizaburo Kawaguchi 《Soil Science and Plant Nutrition》2013,59(4):351-360
The authors reported that the relative bonding strength between ligand of soil colloid surface and cations could be obtained easily by the measurement of MCSA, and that the MCSA corresponded to the constant of Langmuir's adsorption isotherm equation. The relative bonding strength of cations with respect to kaolinitic soil clay at pH 6 was, Cr3+>Fe3+, Al3+>Ga8+>Cu8+>Pb2+>Y3+, La3+>Mn2+>Ni2+, Co2+> Zn2+>Sr2+, Mg2+>NH4+, K+, and with respect to colloid with humus coating, Y3+, La3+>Pb2+>Cu2+, and the other orders were same. The solubility of cations in soil colloid aqueous dispersion system was calculated from the values of MCSAs, and considered as follows, Y3+, La3+, Cu3+, Pb3+, Mn2+, Ni2+, CO2+: concentration in soil solution and soil geochemical mobility may be regulated by the specific adsorption reaction, Zn2+, Mg2+, Sr2+, K+, NH4+: concentration in soil solution and soil geochemical mobility may be regulated by the non-specific adsorption reaction, but at neutral to alkaline condition, Zn2+ and Mg2+ may specifically adsorb on soil, clays, Fe3+, Cr3+, Al3+, Ga3+: concentration in soil solution and soil geochemical mobility may be regulated by the solubility of their oxide hydrates. 相似文献
19.
To determine the degradability of PAHs and PCBs for soil remediation or ecotoxicological risk assessment, a simple method is needed. We tested the suitability of photocatalytic oxidation for this purpose. We determined the concentrations of 20 PAHs and 12 PCBs in four mineral topsoil horizons, six organic horizons, and four particle‐size fractions of each of three soils before and after UV irradiation with TiO2 as a catalyst in suspension. Preliminary experiments showed that in dry soil no photooxidation occurred, but after 48 h of irradiation in suspension the PCB concentrations decreased by up to 40—50 %, while the PAH concentrations did not change significantly. In contrast to this, 95—100 % of PAH and PCB standards spiked on quartz sand were degraded within 8 h, indicating that sorption to organic matter limited degradation of PAHs and PCBs in soil suspensions. There was no difference in the degradation among different individual PAHs and PCBs, respectively, indicating that the degradation did not occur in dissolved state, but in association with soil organic matter. In all samples except one, the degradation of PCBs (10—80 % loss of initial concentrations) was higher than those of the PAHs (0—40 % loss). This suggests that the accessibility of PCBs for OH· radicals generated during irradiation was higher, or the oxidation of PAHs was limited by the properties of the sorbing organic matter. Thus, the tested method was not suitable to predict biodegradability, because it did not reflect the differences in degradability of individual compounds. 相似文献
20.
土壤PAHs污染的微生物修复 总被引：2，自引：0，他引：2
PAHs广泛分布于土壤中,是一种非环境友好型物质。综合介绍了土壤中PAHs的来源、分布与危害,论述了PAHs的致癌毒性的结构特点、土壤PAHs污染的微生物修复原理及近年来可降解PAHs的微生物筛选情况,同时列举了新发现的可降解PAHs的微生物种类,针对土壤PAHs污染的特点提出了原位修复和异位修复两种修复方法以及从土壤性质改良和提高PAHs溶解率两方面促进微生物降解PAHs。 相似文献