土壤原位覆盖对底泥的修复作用研究

在高度厌氧底泥和富营养化水体构成的模拟生态系统中,采用土壤和硅藻土进行原位覆盖,研究了覆盖技术对水．沉积物界面微环境的改善作用和不同覆盖材料对苦草生长的影响。这2种底质覆盖后,表层底泥氧化还原电位（Eh）分别提高了48．37％和46．77％,底层水体的溶解氧消耗降低,水体中的总氮（TN）和总磷（TP）含量降低;与对照箱体的苦草死亡相比,经过土壤和硅藻土覆盖的箱体中苦草正常萌发、定植和生长;硅藻土箱体苦草的生物量、叶绿素和根茎比均高于土壤覆盖箱体。因此,原位覆盖能有效改善底层水体和表层底泥的氧化还原环境,隔绝污染底泥和延缓营养盐释放,为沉水植物种子萌发和幼苗生长提供有利的生境条件。     

土壤柴油污染修复的抽气提取去除实验研究

为得到土壤气相抽提(SVE)去除柴油的优化条件,进行了一维土柱抽气提取去除柴油污染物的实验研究,研究不同初始含水率、不同抽气量对污染土壤中柴油去除率的影响及不同深度残留柴油的变化规律。结果表明：在本实验模拟的范围内,抽气量越大,SVE处理效果越好;初始含水率越低,处理效果越好;此外,不同深度去除率变化的规律基本上是随深度的增大而减小。实验结果可为土壤轻油污染实际治理提供实验数据基础。     

Natural attenuation of diesel aliphatic hydrocarbons in contaminated agricultural soil

A diesel fuel spill at a concentration of 1 L m(-2) soil was simulated on a 12 m(2) plot of agricultural land, and natural attenuation of aliphatic hydrocarbons was monitored over a period of 400 days following the spill after which the aliphatic hydrocarbon concentrations were found to be below the legal contamination threshold for soil. The main fraction of these compounds (95%) remained at the surface layer (0-10 cm). Shortly after the spill (viz. between days 0 and 18), evaporation was the main origin of the dramatic decrease in pollutant concentrations in the soil. Thereafter, soil microorganisms used aliphatic hydrocarbons as sources of carbon and energy, as confirmed by the degradation ratios found. Soil quality indicators, soil microbial biomass and dehydrogenase activity, regained their original levels about 200 days after the spill.     

Efficacy of indigenous soil microbes in arsenic mitigation from contaminated alluvial soil of India

Selected arsenic-volatilizing indigenous soil bacteria were isolated and their ability to form volatile arsenicals from toxic inorganic arsenic was assessed. Approximately 37 % of AsIII (under aerobic conditions) and 30 % AsV (under anaerobic conditions) were volatilized by new bacterial isolates in 3 days. In contrast to genetically modified organism, indigenous soil bacteria was capable of removing 16 % of arsenic from contaminated soil during 60 days incubation period while applied with a low-cost organic nutrient supplement (farm yard manure).     

Water and soil contaminated by arsenic: the use of microorganisms and plants in bioremediation

Environmental Science and Pollution Research - Owing to their roles in the arsenic (As) biogeochemical cycle, microorganisms and plants offer significant potential for developing...     

原位电阻热脱附修复氯代烃污染土壤

针对原位电阻热脱附(ISERH)技术基础性研究不足、缺乏小试设备研发等问题,利用自主研发ISERH设备,以1,2-二氯乙烷和氯苯为目标污染物,探究了ISERH过程中土壤温度变化及设定温度、加热时间、污染物种类、老化时间对污染物热脱附效果的影响.结果表明,在热脱附过程中氯代烃污染土壤的主要阴离子SO42-和Cl-含量分别...     

重金属与土壤微生物的相互作用及污染土壤修复

阐述了微生物与重金属间的相互作用 ,指出土壤重金属污染影响微生物活性、生物量 ,且重金属对微生物具有一定的生态毒性。可通过微生物的氧化 还原作用、生物吸附富集和溶解作用 ,达到修复重金属污染土壤的目的。     

Soil amendments reduce trace element solubility in a contaminated soil and allow regrowth of natural vegetation

We tested the effects of three amendments (a biosolid compost, a sugar beet lime, and a combination of leonardite plus sugar beet lime) on trace element stabilisation and spontaneous revegetation of a trace element contaminated soil. Soil properties were analysed before and after amendment application. Spontaneous vegetation growing on the experimental plot was studied by three surveys in terms of number of taxa colonising, percentage vegetation cover and plant biomass. Macronutrients and trace element concentrations of the five most frequent species were analysed. The results showed a positive effect of the amendments both on soil chemical properties and vegetation. All amendments increased soil pH and TOC content and reduced CaCl(2)-soluble-trace element concentrations. Colonisation by wild plants was enhanced in all amended treatments. The nutritional status of the five species studied was improved in some cases, while a general reduction in trace element concentrations of the aboveground parts was observed in all treated plots. The results obtained show that natural assisted remediation has potential for success on a field scale reducing trace element entry in the food chain.     

中原油田石油污染土壤原位生物修复技术实验研究

通过实验室选择性富集培养,从中原油田石油污染土壤中获得了能以中原原油为碳源快速生长的石油降解菌群。结合黑麦草（Ryegrass）和苜蓿（Alfalfa）,采用该降解菌群对原油污染土壤进行了原位生物联合修复实验。接入降解菌的实验区分种植黑麦草、种植苜蓿、未种植区,另设黑麦草区和空白区。经过99 d的生物修复,石油烃累计降...     

Correction to: Water and soil contaminated by arsenic: the use of microorganisms and plants in bioremediation

Environmental Science and Pollution Research -     

油污土中降解柴油细菌的分离鉴定及降解能力研究

从所采集柴油污染土壤样品中富集、分离得到柴油降解优势菌株,命名为B-3和B-4.根据其生理生化性质及16S rDNA序列比对分析,确定2株菌分别属于Tetrathiobacter kashmirensis、假单胞菌属(Pseudomonas sp.).由于实验中,B-3的生长曲线较特殊,故以B-3和典型石油烃降解菌假单...     

功能微生物对污染农田土壤中铅锌的溶出实验

用微生物修复重金属污染的土壤是当今的研究热点之一。试图寻找一类可以增加土壤中重金属铅、锌的可溶态的功能微生物,并研究该微生物在不同土壤含水率和不同投菌比条件下对铅、锌溶出作用的影响。最终筛选出符合条件的菌JK3,并发现当土壤含水率为35%,投菌比为0.15 mL/g土(菌液OD=1)时,土壤中铅和锌的可溶态增加量最多。其中,可溶态铅的含量由原来的0.49 mg/kg增加到了5.04 mg/kg,可溶态锌的含量由原来的2.23 mg/kg增加到了22.44mg/kg。该方法为后续用植物提取或化学淋洗等方法将土壤中的重金属彻底去除提供了可能。     

Pressure-assisted ozonation of PCB and PAH contaminated sediments

Sediment contamination by recalcitrant organics such as polychlorinated biphenyls (PCBs) and polycyclic aromatic hydrocarbons (PAHs) is prevalent and of a great concern. Remediation efforts are hampered by the hydrophobic nature of the contaminants that limits their availability as well as by the sediment matrix that limits their exposure to treatment agents. Using contaminated sediment samples from the Passaic River, St. Louis River, Waukegan Harbor, and Wells National Estuarine Research Reserve, this research demonstrated a new ozonation technique that incorporates rapid, successive cycles of pressurization (690 kPa) and depressurization, enabling more effective treatment than conventional ozonation would. Conventional ozonation reached maximum 60% and 40% removal of PAHs from the Passaic River (40 mg kg(-1) initially) and St. Louis River sediment (520 mg kg(-1) initially), respectively, in 1h; however, removals ceased despite prolonged treatment for 2h. The pressure-assisted technique removed 96% of PAHs from both river sediments within 1h; it completely removed both PAHs (16 mg kg(-1) initially) and PCBs (5.1 mg kg(-1) initially) from the Waukegan Harbor sediment in 0.5 h. The heightened treatment is explained by soil aggregate fracturing upon pressure cycles that exposes the contaminants as well as by the confluence of hydrophobic contaminants and O(3) at the gas-liquid interface in the presence of microbubbles. The technique is expected to accelerate O(3) treatment of a wide range of organic contaminants, and it may provide treatment to dredged and stored contaminated sediment.     

Modification of the degradative capacity of a soil artificially contaminated with diesel

Samples of an Ah horizon from a Cambisol under oakwood vegetation were artificially contaminated with diesel (at doses of 20, 40, 80, 160 and 400 microl g(-1)) under laboratory conditions. The presence of the contaminant caused a decrease in the microbial biomass and in phosphomonoesterase, beta-glucosidase and particularly, urease activities. In contrast, the basal respiration and mineralization of nitrogen, specifically ammonification, both increased. The microorganisms that survived in the contaminated soil showed increased metabolic activity, as a result of their use of dead microorganisms as a substrate and of a lack of competition. Although the results indicate that the properties related to the degradative capacity of the soils varied differently in response to the contamination, the use of a biochemical quality index (including different biochemical properties), which was designed for estimating the degree of deterioration of the soil, revealed a clear decrease in the biochemical quality of the diesel-contaminated soils.     

Influence of initial pH on bioleaching of heavy metals from contaminated soil employing indigenous Acidithiobacillus thiooxidans

Bioleaching of heavy metals from contaminated soil was carried out employing indigenous sulfur oxidizing bacterium Acidithiobacillus thiooxidans. Experiments were carried out to assess the influence of initial pH of the system on bioleaching of chromium, zinc, copper, lead and cadmium from metal contaminated soil. pH at the end of four weeks of bioleaching at different initial pH of 3-7 was between 0.9 and 1.3, ORP between 567 and 617mV and sulfate production was in the range of 6090-8418mgl(-1). Chromium, zinc, copper, lead and cadmium solubilization ranged from "59% to 98%" at different initial pH. A. thiooxidans was not affected by the increasing pH of the bioleaching system towards neutral and it was able to utilize elemental sulfur. The results of the present study are encouraging to develop the bioleaching process for decontamination of heavy metal contaminated soil.     

A bench-scale investigation of land treatment of soil contaminated with diesel fuel.

A bench-scale investigation (soil pan testing) was conducted with the objective of studying degradation rates of diesel contaminated soil (2500 and 10,000 ppm by weight of total petroleum hydrocarbons (TPH) to dry weight of soil) under different treatment conditions over a 17 week testing period. The greatest degradation of the diesel contaminated soil was obtained with the addition of nutrients (Co = 10,000 ppm of TPH; k = 0.19 week-1). 'k' for soil not amended with nutrients was 0.07 week-1. The control cell (C0 = 2500 ppm TPH), with sodium azide (to suppress degradation) was compared with an experimental cell of 2500 ppm initial concentration of TPH without nutrient amendment. The control cell exhibited a relatively low uniform degradation (k = 0.08 week-1) of TPH over the duration of the experiment with reasonable first-order kinetic regression statistics.     

生物通风技术修复柴油污染土壤的土柱模拟实验

生物通风技术是将土壤气相抽提和生物降解结合起来的原位强迫氧化降解方法,对于修复因地下储油罐泄漏引起的土壤污染具有广阔的应用前景。通过室内土柱模拟柴油泄漏污染土壤,分析了不同历时残余总石油烃(total pe-troleum hydrocarbon,TPH)的平衡分布规律以及土壤中不同深度柴油量、总柴油量的变化。结果表明:(1)各柱残余TPH剖面分布差异的原因受土柱的初始装填情况的影响较大;(2)残余TPH平衡分布曲线呈双峰型的土柱,柴油的去除主要以挥发作用及生物降解作用为主;(3)挥发作用主要是由通风孔隙体积数及土壤含水率来影响的;重力作用则主要是由初始油浓度、土壤含水率、C∶N∶P影响的;除通风方式外,其余4个因素都对生物降解作用有影响;(4)初始油浓度较大,土壤含水率较小的柱8和柱11,生物降解作用最明显,柴油去除效果最好。该成果可为生物通风过程的强化提供理论依据。     

强化生物通风修复过程中柴油衰减规律及其影响因素研究

强化生物通风技术对于修复因地下储油罐泄漏引起的土壤污染具有很大的应用前景。通过室内土柱模拟柴油泄漏污染土壤,从土柱中总石油烃（total petroleum hydrocarbon,TPH）剖面分布随时间的变化及降解模式角度,分析了其自然衰减和强化生物通风过程。结果表明：初始柴油浓度直接影响着各柱在自然衰减和强化生物通风过程中柱内的残余TPH平衡分布曲线的形状和浓度峰值位置;在前期自然衰减过程中（约1个月）,当土壤中的柴油浓度为5 000～40 000 mg油/kg土时,整个柱内TPH变化的主要原因是重力扩散迁移的结果;当土壤中的柴油浓度≤5 000 mg油/kg土时,其TPH的变化不仅是重力扩散迁移作用的结果,生物降解作用也存在;通风约2个月后,抽提作用对于保持土柱上部柴油浓度稳定变化的意义较为突出。     

改性沸石对土壤铅、锌赋存形态的影响简

通过室内土壤培养实验,研究改性沸石对污染土壤中Pb、Zn赋存形态的影响。结果表明,土壤中的Pb主要是以Fe-Mn氧化物结合态存在,土壤Zn主要以残渣态存在。添加天然沸石和改性沸石不同程度地降低土壤酸提取态Pb、Zn的含量,提高土壤残渣态Pb、Zn的含量。与CK处理相比,添加4种沸石导致土壤酸提取态Pb含量降低8.7%~40.3%,土壤酸提取态Zn含量降低10.5%~49.8%（培养1个月）。硝酸钾改性沸石比天然沸石更能显著地降低土壤酸提取态Pb、Zn的含量,而氢氧化钠改性沸石和硝酸钾改性沸石比天然沸石更能显著地降低土壤酸提取态的Zn含量。培养1、2和3月后,不同沸石处理导致土壤残渣态Zn比率分别比CK处理提高14.4%~23.5%、19.6%~23.7%和1.9%~11.1%。研究结果表明,天然沸石经过一定方法改性后,是固定污染土壤Pb、Zn的潜在改良剂。