石油污染土壤的微生物修复及土壤微生物活性变化

为快速有效地测定石油污染土壤中功能性微生物的活性变化,分别以石油烃、正十六烷烃、多环芳烃为自定义碳源,应用Biolog法研究油污土壤生物修复过程中石油烃、烷烃、多环芳烃降解菌的代谢活性.结果显示,向油污土壤中投加混合降解菌群进行生物强化修复处理,可以有效去除土壤中的石油烃,修复13周土壤中石油烃去除率达到42.3%;生物刺激和自然修复对土壤石油烃的去除率分别为28.3%和20.5%.Biolog测定结果表明,生物强化法修复初期的土壤微生物群落对石油烃、烷烃两种碳源的代谢能力较强,而生物刺激法修复后期的土壤微生物群落对烷烃有较强的代谢能力;不同处理的土壤微生物群落比较偏好、利用率较高的碳源是石油烃,其次是烷烃,而对多环芳烃几乎不利用;土壤中石油烃、烷烃降解菌的活性越大,土壤微生物对石油烃的去除效率越高.上述研究结果说明,通过利用Biolog法测定土壤微生物活性变化可有效指示土壤中石油烃的去除效果.     

植物与微生物对石油污染土壤修复的影响

为了研究生物对石油污染土壤的修复效果,在从石油污染土壤中筛选石油降解微生物的基础上,采用盆栽试验,进一步研究了4种植物和筛选到的微生物对石油污染土壤修复的影响.选择中原油田地区的原油和潮土,采取人工污染方法,设计石油污染水平为15 g·kg-1.试验设置3类处理,即单独添加微生物、单独种植植物(分别为向日葵、狗牙根、棉花、高丹草)、微生物分别与4种植物(向日葵、狗牙根、棉花、高丹草)组合.结果表明:在石油污染土壤中单独添加石油降解微生物,120 d时,石油降解率达到67.0%;向日葵、狗牙根、棉花、高丹草对土壤中石油降解也具有一定效果,120 d时,石油降解率分别达到38.23%、36.57%、40.67%、38.67%;添加微生物和种植植物联合对石油降解能力大小顺序为棉花+微生物＞向日葵+微生物＞狗牙根+微生物＞高丹草+微生物.其中,棉花与微生物联合修复120 d可以使污染土壤石油降解率达到85.67%,在各种处理中对污染土壤中石油的降解效果最好.     

添加不同营养助剂对石油污染土壤生物修复的影响

实验室条件下研究NPK复合肥、诺沃肥和腐殖酸三种物质不同配比添加对石油污染土壤的生物修复效果.在60d的修复实验中,定期取样测定土壤含油量、总异养菌数、石油烃降解菌数和脱氢酶活性,并采用PCR-DGGE技术研究修复过程中微生物多样性变化.结果表明,NPK肥的添加和NPK肥-诺沃肥-腐殖酸复合添加能够提高土壤中微生物的数量、微生物多样性和脱氢酶活性.在含油量为84600mg.kg-1的土壤中,添加营养助剂的处理60d后石油烃降解率为31.3%—39.5%,不添加营养助剂的石油烃降解率仅为3.5%.NPK肥-诺沃肥-腐殖酸复合添加对石油烃的降解率要高于NPK肥的单独添加(高8%),其原因可能是诺沃肥-腐殖酸能够有效提高土著微生物的活性,增加微生物的多样性,增强石油烃的降解.     

微生物修复石油污染土壤的生态毒性指示

发光菌的相对发光度和植物光合色素含量以及土壤酶活性是土壤石油污染程度和生态毒性强弱的综合反映。为探究不同生物指示方法对石油污染土壤生态毒性的指示效果以及污染土壤在生物修复过程中毒性的变化规律,采用前期筛选分离的三株对石油烃具有良好降解效果的降解菌构建混合菌体系,开展石油污染土壤模拟微生物修复实验。文章首先以明亮发光杆菌为指示生物考察不同修复时期土壤生态毒性,并以高等植物毒性试验以及土壤酶活性试验结果作为辅助证据从生态学角度揭示修复过程中石油污染土壤生态毒性的变化,并分析了以上3种指示方法的一致性。结果表明,该混合菌能高效降解对石油烃污染物,污染土壤经40 d修复后,石油烃污染物浓度从5 000 mg·kg-1降到1 781 mg·kg-1,去除率达到64%。高等植物生态毒性试验、土壤酶活性试验与发光菌生态毒性试验结果呈现良好的一致性,石油污染土壤的生态毒性随着微生物修复过程的进行呈先上升后下降的趋势。具体而言,修复初期的土样对小麦光合色素含量的抑制作用最大,叶绿素a含量相对于对照组降低了39.3%,仅为(1.36±0.04)mg·g-1;土壤过氧化氢酶酶活性与石油烃残留量呈极显著负相关关系(-0.973);污染土壤生态毒性在修复的第8天达到最大,其二氯甲烷/二甲基亚砜浸提液中发光菌的相对发光度为18.1%,与0.187 mg·L-1 Hg Cl2的毒性相当。明亮发光杆菌的相对发光度和小麦光合色素含量以及土壤过氧化氢酶活性能较好地指示石油污染土壤在生物修复过程中的生态毒性,可作为石油污染土壤微生物修复效果的指示生物。     

水面流湿地系统水质净化效果及河道洗盐动态规律--以天津泰达再生水景观河道生态修复中试工程为例

分析研究了天津开发区滨海盐碱土地区再生水景观河道水面流湿地生态修复中试工程水质净化效果以及河道洗盐动态变化规律。结果表明:水面流湿地系统对COD去除效果不明显,去除率最高仅为30 % ;对氮、磷具有较高的去除率,TN、NH4-N及NO3 --N的平均去除率分别达到6 5 %、38%和6 0 % ,TP和PO43 -的平均去除率分别达到87%和90 .2 %。另外在土壤盐分不断溶出的同时河道洗盐效果是明显的     

磁性纳米羟基磷灰石对污染土壤中镉的吸附—移除效果

为从污染土壤中吸附移除重金属镉(Cd),将共沉淀法合成的磁性纳米羟基磷灰石(nHAP@Fe₃O₄)分别按0、0.1%、0.5%、1.0%、3.0%比例添加至土壤中,在修复21、30、45 d时,磁分离nHAP@Fe₃O₄与土壤,考察nHAP@Fe₃O₄对土壤Cd的去除、材料的回收效果及修复后土壤理化性质的变化。结果表明,w(Cd)为2.510 mg·kg^-1的重污染稻田土壤中添加1.0%nHAP@Fe₃O₄,修复21 d时土壤Cd去除和材料回收效果最好,Cd平均去除率和材料回收率分别为16.45%和85.33%;nHAP@Fe₃O₄能明显降低土壤Cd的可交换态,促使其向较稳定的形态转化;经nHAP@Fe₃O₄修复后的土壤pH值升高,CEC有所降低,土壤颗粒间孔隙增大。利用磁性将nHAP@Fe_3<...     

生物刺激法对石油污染荒漠土的修复效应

利用生物法修复有机物污染土壤是一种低成本、无二次污染物产生的绿色修复方法,受到国内外学者的极大关注.目前,国内对石油污染土壤生物修复技术的研究工作集中于中东部地区,对干旱区石油污染土壤修复工作非常欠缺.本研究以干旱区石油污染荒漠土为研究对象,通过投加不同水平的营养元素,以刺激土壤微生物活性,探讨生物刺激法修复干旱区石油污染土壤的可行性及修复效果,为建立面向干旱区的石油污染土壤生物修复技术提供科学依据和技术支撑.1材料与方法1.1土壤来源实验土样采自克拉玛依油田采油过程中污染的表层20 cm荒漠土.土壤基本理化性质为:pH 7.4,土壤有机质、总氮、总磷含量分别为1.3%、0.02%、0.03%.砂粒(0.05—2 mm)、粉粒(0.05—0.02 mm)、黏粒(<0.002 mm)含量分别为     

超声波强化电动-膨润土吸附处理土壤镉污染的研究

电动修复和吸附技术广泛应用于土壤中重金属镉的去除。为提高电动修复土壤镉污染的去除效率、解决修复过程中引起的土壤pH突变、降低处理成本,该研究将超声波强化与电动力修复-吸附技术结合起来。实验结果表明:钠基膨润土是一种非常良好的吸收材料,对重金属镉具有很强的吸附特性,吸附速率非常快,一般35min就能吸附完成。在电动修复处理过程中采用的电场强度、土壤的pH值是影响镉去除效果的主要因素,电压强度1 V·cm~(-1),每隔2 d周期切换电极条件下,镉的去除率能达到69.5%;最终处理结束后,土壤pH值仅比初始值略有降低。进一步实验表明,超声波强化后能显著提高电动-膨润土吸附修复装置对镉的去除率,在同样电压强度1 V·cm~(-1)、超声波装置功率100 W条件下,土壤中的镉具有更高的去除率,能达到84.8%,比不施加超声波强化时镉的去除率提高了15.3%,并在一定程度了节约了能耗;超声波强化电动-膨润土吸附联合修复技术,不使用有机酸等化学淋洗剂,基本保持原有土壤环境,是一种对环境友好的原位土壤重金属镉去除技术。     

应用脂肪酸甲酯淋洗去除土壤中多环芳烃

针对煤气厂土壤等高浓度多环芳烃污染土壤修复困难的现实,采用易生物降解的新型淋洗剂脂肪酸甲酯淋洗修复高浓度多环芳烃污染的土壤,同时进行了以甲醇、植物油(大豆油)作为淋洗剂的淋洗实验,比较不同淋洗剂的淋洗效果.结果证明脂肪酸甲酯对人工模拟污染土壤中蒽、荧蒽、芘、苯并(a)芘的去除率可以达到80%—95%,对煤气厂土壤中多环芳烃的去除效果也非常明显,总多环芳烃的去除率达到41%.脂肪酸甲酯的淋洗效果要优于其它两种淋洗剂.     

硝基酚、六氯苯污染土壤的微波修复

以典型有机污染物4-硝基酚(4-nitrophenol,4-NP)和六氯苯(hexachlorobenzene,HCB)污染土壤为处理对象,采用高效吸收微波且保温性能良好的碳化硅材料制成圆柱状装土容器,研究以微波为热源、碳化硅为热传导材料的微波修复设备对污染土壤的修复效果.结果表明,该设备对土壤中有机污染物有较好的去除效果,30 min内去除率均可达到90%以上.有机物的去除不仅是由于碳化硅被加热后的热传递效应,且透过容器的部分微波也可直接作用于污染土壤.实验考察了微波辐照时间、污染物初始浓度、土壤量及含水率、敏化剂等因素对修复效果的影响.辐照时间、土壤量和含水量显著影响土壤升温行为和污染物去除率,而污染物初始污染浓度对去除率影响较小.与马弗炉加热处理效果进行了比较,表明微波加热修复技术在土壤的升温速率及有机物去除率方面均有显著优势.     

发酵牛粪和造纸干粉对土壤中多环芳烃降解的影响

运用泥浆反应法研究添加发酵牛粪和造纸干粉对土壤中多环芳烃(PAHs)降解的影响.试验按水土比2:1制成泥浆反应器,设置对照、添加2.5%发酵牛粪和添加2.5%造纸干粉等3个处理,25～28℃摇床培养,分别于10、20、30 d采样测定土壤中多环芳烃降解菌的数量和多环芳烃含量.结果发现,所有处理土壤中多环芳烃的含量均随培养时间的延长而逐渐降低,而添加发酵牛粪和造纸干粉均有利于提高土壤中多环芳烃降解菌的数量,在培养30 d后土壤中多环芳烃的降解率分别从对照处理的19%显著提高到37%和35%(P<0.05).结果还发现,多环芳烃分环降解率随苯环数增加而下降,培养30 d后土壤中2环多环芳烃的降解率达95%以上,3环多环芳烃的降解率为50%左右,对照处理4～6环多环芳烃的降解率为7%～13%,而添加发酵牛粪和造纸干粉处理土壤中4～6环多环芳烃的降解率显著提高到21%～28%(P<0.05),但对2～3环多环芳烃的降解无明显影响,表明这两种物质对土壤中多环芳烃降解的影响关键在于促进高环多环芳烃降解菌的生长繁殖及降解活性.     

木质素降解真菌的筛选及产酶特性

通过定性、定量系列实验从土壤中筛选到5株有木质素降解能力的低等真菌，经鉴定属于青霉属、镰刀霉属、曲霉属和木霉属，其中青霉属和镰刀霉属是土壤中木质素转化的主要作用者．降解能力最强的简青霉Penicillium simflitcissimum H5培养13d可降解Kraft木质素40．26％，产酶研究发现，该菌分泌胞外木质素过氧化物酶和漆酶，其中前者主要在培养前期产生，后者在整个培养过程中均有较好的活性．图4表1参14.     

Tolerance and accumulation of lead in Vetiveria zizanioides and its effect on oil production

Experiments were conducted to evaluate lead tolerance and accumulation in vetiver grass Vetiveria zizanioides (L.), grown in hydroponics and a pot study and to examine the effect of lead on vetiver oil production. Elevated concentrations of lead decreased the length of shoots and roots of plants. However, vetiver grown in highly contaminated soils showed no apparent phytotoxicity symptoms. Lead concentrations in the shoots and roots of vetiver plants grown in hydroponics were up to 144 and 19530 mg kg(-1) and those grown in soil were 38 and 629 mg kg(-1), respectively. Lead had an effect on vetiver oil production and composition by stimulating oil yield and the number of its constituents. Oil yield ranged from 0.4-1.3%; the highest yields were found in plants grown in nutrient solution with 100 mg Pb l(-1) for 5 weeks (1.29%) and 7 weeks (1.22%). The number of total constituents of vetiver oil also varied between 47-143 compounds when lead was presentin the growth medium. The highest number (143) was found in plants grown in soil spiked with 1000 mg Pb kg(-1). The predominant compound was khusimol (10.7-18.1%) followed by (E)-isovalencenol (10.3-15.6%). Our results indicated that lead could increase the oil production of vetiver.     

Degradation of biochanin A in soil

Degradation of biochanin A, 400 μg (1.41 μmol) per gram of dry soil, was studied and the initial degradation products, dihydrobiochanin A, pratensein and genistein were identified and quantified. The maximum concentrations of these compounds were determined as 166 pmol/g dry soil after 2 days of incubation, 175 pmol/g dry soil after 1 day and 1,236 pmol/g dry soil after 1 day, respectively. Biochanin A and the initially formed products degrade too fast to be responsible for clover soil sickness (DT₉₀ <20 days), but could be precursors for the responsible compounds. The immediate degradation products from biochanin A are all biologically active and are the prime candidates for a reduction of weed pressure caused by clover.     

Vertical infiltration of fuel oil hydrocarbons in an agricultural soil

The influence of rainfall, air temperature and soil moisture on the vertical mobility in the soil of fuel oil hydrocarbons (HC) was investigated in a field experiment. A controlled spreading of fuel oil (nC10‐nC25) was performed at a rate of 5 L HCm^‐2 on an agricultural soil in summer and in winter. Concentration, chemical composition of HC and soil moisture were regularly determined at different soil depths between 0 and 140 cm, 1 h, 3, 8and 15 days (d) after the spreading of oil. Sorption of hydrocarbons onto the organo‐mineral matrix of the soil was studied in laboratory experiments. The results showed that in summer, with an air temperature of 24°C and without water leaching in the soil profile, 65% of the initial HC remained trapped in the 0–140 cm soil layer, about 20% of the HC volatilized and around 15% migrated deeper. A vertical selective migration of the lightest (nC10‐nC15) HC (naphthas) was shown lSd after the spreading of fuel oil. Naphthas progressively reached the 120–140 cm soil layers whereas the heavy fractions of oil (nC17‐nC25) migrated and concentrated in the 0–60 cm soil layers. In winter, when soil was regularly watered by rainfalls and at low air temperatures, only 47% of the initial HC remained in the 0–140 cm profile after 15 d. A fast vertical infiltration of naphthas occurred within the first 3 d. After 15 d, all HC were detected in the same relative amounts as in the initial oil in the whole profile. Volatilization was negligible in winter and an increase in the migration of total oil at depth in the soil profile was shown. As inferred from the laboratory experiments, the high soil moisture led to the decrease in HC sorption on the organo‐mineral matter of the soil.     

Umweltschäden durch Heizöl nach Hochwasserereignissen

Background Due to high safety measures in production, transport and storage of fuel oil it rarely occurs, that fuel oil will be released in the environment. One exception of this experience was the fuel oil releases of private fuel oil tanks during the “century flood” 2002 in Germany. By order of IWO (Institut für wirtschaftliche Oelheizung e.?V.), the authors investigated the environmental behaviour of fuel oil after flood incidents. Aim Due to the fast spreading of the fuel oil on water surfaces and the contamination of huge areas one expects large environmental harm. For appraisal the behaviour of fuel oil in water and soil must be studied in detail as well as the effect on high and low developed animals and plants, on water organisms and on the flora and fauna of soil. From the valuation of the environmental harm official measures and measures of precaution and safety by manufacturer and user of private fuel oil installations can be derived. Main features For considering the various aspects the authors studied the extensive analyses of the special measuring programme of Saxony-Anhalt, used interviews of concerned persons (private persons and officials), aerial photos, extensive study of literature including eco-toxicological investigations, experiences of more than 70-years applications of fuel oil in plant protection and practical experiences at large field redevelopment of oil damages following averages and accidents. The authors valuated on the base of results of analyses and on own calculations. Results The release of fuel oil in the air is no particular problem because about 40?% of the oil fast evaporate and will be decomposed to carbon dioxide and water. In addition to the evaporation a characteristic behaviour is fast spreading of the fuel oil on the water surface to very thin layers. For a typical coloured oil layer e.?g. one cubic meter of oil is spread on a water surface of about 3?km², this corresponds to 3?ml/m² surface and contaminates the soil after drying up with about 3?µg/kg soil some orders less than the natural content of hydrocarbons in soil. Because of the absorption capacity of soil and the microbial decomposition by everywhere existing hydrocarbons decomposing micro-organisms the oil infiltrates only a few centimetre and will be decomposed in a few months, so that ground water detriments not arise practically. By measurements a few months after fuel oil release in the flood 2002 oil components in the soil could not be detected. Discussion Acute injuries of micro-flora and -fauna in soil and water by fuel oil cannot be excluded from the first. Thus the limiting values of injuries for some water organisms are below 1?mg/l. According to the special measuring programme at the flood 2002 in Saxony-Anhalt however the measured values were mostly wide below of this limit. In detail the spreading and evaporation of fuel oil on water surfaces, the propagation and decomposition of fuel oil in soil will be described. A quantitative valuation of fuel oil distribution in a real flood incident will be given. Conclusions Particular measures of redevelopment of soil for fuel oil release after flood incidents are not necessary normally. Even at the redevelopment after transport damages or at devastated sites with essential higher oil contaminations of soil in comparison to fuel oil release after flood incidents high decomposition rates are obtained by normal soil improving measures supporting the natural micro-organisms in reducing the hydrocarbon concentration for 70–90?% after a few months. Perspectives With the described results a realistic valuation of the environmental harm of fuel oil release after flood incidents could be given. From this qualified measures can be derived for official decisions and precautionary and reliable activities at fuel oil installations of flood endangered areas.     

Effect of oil pollution on function of sandy soils in protected deserts and investigation of their improvement guidelines (case study: Kalmand area,Iran)

Soil pollution is one of the most dangerous sorts of environmental pollutions because of waste materials, fossil fuels, etc. Unfortunately in developing countries, there are very few arrangements to prevent soil pollution due to the fossil fuels and to improve polluted soil. In this research, influences of gas oil on properties of Kalmand protected area’s sandy soil near Yazd, Iran, were studied. It was found that gas oil constituted 5.25% of soil weight in the refueling station in the region. Therefore, cleaning and strengthening of the soil by adding cement rather than expensive and complicated methods were the most important goals of this research. First, the influence of gas oil on soil properties was studied, and to improve the soil, different percentages of ordinary portland cement were added to the polluted sand to study the improved soil properties using laboratory tests. It was found that unconfined compressive strength, cohesion, and angle of internal friction of sample with 16% cement and 8% gas oil after 28 days of curing were higher than those of the specimen of 6% cement and 14% gas oil, at 4.6, 5.4, and 1.3 times, respectively. Moreover, based on falling head tests it was observed that permeability of the stabilized specimens decreased substantially. From SEM tests, fewer voids were observed in the stabilized samples, which led to less pollutant penetration into the soil. According to EDX, although dangerous elements in the contaminated specimen made up 3.99% of the specimen total weight, addition of cement introduced considerable amounts of elements that are vital for pozzolanic reactions. Therefore, it can be concluded that addition of cement to the gas oil-polluted soil not only can improve geotechnical properties of the soil and reduce its permeability, but also is very efficient for environmental issues.     

Relative bioavailability of soil-bound chlordecone in growing lambs

The pollution of soil with the pesticide chlordecone (CLD) is a problem for the use of agricultural surfaces even years after its use has been forbidden. Therefore, the exposure of free-ranged animals such as ruminants needs to be investigated in order to assess the risk of contamination of the food chain. Indeed, measured concentrations could be integrated in a lowered extent if the soil binding would reduce the bioavailability of the pesticide. This bioavailability of soil-bound CLD in a heavily polluted andosol has been investigated relatively of CLD given via spiked oil. Twenty-four weaned lambs were exposed to graded doses of 2, 4 or 6 μg CLD/kg body weight during 15 days via the contaminated soil in comparison to spiked oil. The concentration of this pesticide has been determined in two target tissues: blood serum and kidney fat. The relative bioavailability (RBA) corresponds to the slope ratio between the test matrix-contaminated soil- in comparison to the reference matrix oil. The RBA of the soil-bound CLD was not found to significantly differ from the reference matrix oil in lambs meaning that the pesticide ingested by grazing ruminants would not be sequestered by soil binding. Therefore, CLD from soil gets bioavailable within the intestinal level and exposure to contaminated soil has to be integrated in risk assessments.     

固定化微生物对土壤中苯并芘的降解

研究了3株细菌与3株真菌对土壤中苯并芘（BaP）的降解动态,从中筛选出1株细菌（Bacillus sp.）和1株真菌（Mucor sp.）,并采用吸附法将混合菌固定在改性后蛭石上,研究了固定化混合菌对土壤中BaP的降解效果。结果表明：细菌中芽孢杆菌（Bacillus sp.,SB02）降解率最高,42 d对B[a]P的降解率为33.0%,降解速率也最快,1周可降解12.6%的BaP;真菌中毛霉（Mucor sp.,SF06）降解率最高,42 d对B[a]P的降解率为69.7%;以改性后蛭石为载体用吸附法制得的固定化混合菌,传质性能好,对BaP的降解率42 d可达95.32%,高于游离菌20个百分点。     

Changes in some soil properties at different incubation periods after tobacco waste application

In this study changes in organic carbon (OC), basal soil respiration (BSR), nitrate nitrogen (NO3-N), electrical conductivity (EC) and aggregate stability (AS) of a clay loam soil due to tobacco waste (TOW) application were monitored for 240 days. After incorporating 5% TOW into soil according to oven dry weight basis, soil samples were incubated at field capacity for 20, 40, 80, 140 and 240 days under a greenhouse condition. TOW application significantly increased all soil properties over the control treatment Soil OC and AS values had significant positive correlations each other and with the other soil properties. Soil OC, BSR and AS values significantly increased from 0.12%, 0.03 microg CO2-C g(-1) dry soil 24 hr and 20.7% in control treatment to 1.13%, 3.7 microg CO2-C g(-1) dry soil 24 hr and 54.4% in TOW treatment, respectively in 20 days. While the highest NO3-N (1780 ppm) was found in 40 days, the highest EC (3.35 dS m(-1)) was in 240 days after TOW application. Disaggregation occurred in all treatments after 20 days of incubation due to probably the more substrate demands of microorganisms in soil.