天然地下水环境四氯乙烯的强化生物降解

采用批实验方法, 以天然地下水为基础培养液, 利用在实验室条件下培养驯化的微生物, 以醋酸作为共代谢基质, 加入酵母粉提供氮源, 研究了四氯乙烯(PCE) 的降解效果.研究表明, 通过强化影响PCE降解的某些因素, 在20℃的地下水环境中, PCE可以很快转化为三氯乙烯(TCE), 并可以进一步转化为二氯乙烯(DCEs), 但没有检测到DCEs的脱氯产物.PCE的脱氯速率为0.1848d-1, 半衰期为3.75d.亦研究了低温环境下PCE的降解效果.结果表明, 在低温环境下, PCE也可以发生生物降解, 但是脱氯速率相对较慢, 为0.0761d-1, 半衰期为9.11d, 且终产物为TCE.      

不同基质共代谢降解地下水中四氯乙烯的研究

文中以甲醇、乙醇、甲酸盐、乙酸盐、乳酸盐和葡萄糖作为共代谢基质,利用某污水处理厂厌氧池中的污水(泥)作为接种物,对厌氧微生物进行培养和驯化,降解四氯乙烯(PCE)。实验结果表明,在厌氧污水(泥)和土壤混合环境下培养的微生物,以COD为培养指标,11d可培养成熟。6种基质均能使PCE还原脱氯降解成三氯乙烯(TCE)和1,1-二氯乙烯(1,1-DCE),PCE的降解均符合一级反应动力学方程,反应速率常数大小依次为K乙酸盐>K葡萄糖>K乳酸盐>K乙醇>K甲酸盐>K甲醇,其中乙酸盐是最有效的共代谢基质,其反应速率常数为0·6632d-1。     

以醋酸为共代谢基质时四氯乙烯的生物降解初步研究

四氯乙烯(PCE)是一种广泛用于干洗和脱脂的有机溶剂,是地下水中常见的污染物.在本实验中,将某肉联厂厌氧污泥接种到土壤中,进行微生物培养.当系统中的微生物活性较高时,以醋酸为共代谢基质,进行驯化实验,当系统中的微生物适应浓度为120μg/L的PCE之后,对PCE在厌氧条件下的降解情况进行研究.研究结果表明,将厌氧污泥接种到土壤中培养的微生物,在以醋酸为共代谢基质的条件下,可以使PCE很快转化为三氯乙烯(TCE),并可以进一步转化为二氯乙烯(DCEs).PCE在天然地下水中的半衰期为108d,本实验PCE降解的半衰期为2.95d,反应速率常数为0.2342d-1.     

地下水中三氯乙烯-苯酚的好氧共代谢的实验研究

以苯酚作为三氯乙烯（TCE）降解的共代谢基质,用瓦勃氏微量呼吸测压仪（简称瓦呼仪）作为测试手段,分析了经苯酚驯化后的混合微生物对苯酚、TCE的降解特性;并讨论了以苯酚作为共代谢基质时TCE降解的可能性。实验结果表明：未驯化的活性污泥不能降解TCE; 经苯酚驯化后的活性污泥,当TCE的质量浓度为50 μg/L时其降解效果较好,TCE的氧化率达3369%;TCE的质量浓度为100 μg/L时其降解效果较差,其氧化率仅为3.2%;苯酚和TCE共代谢降解时,苯酚的存在促进了TCE的降解,当苯酚质量浓度为40 mg/L、TCE质量浓度为50 μg/L时共代谢降解效果最好,TCE的氧化率为79.11%。     

四氯乙烯的生物吸附和厌氧生物降解研究

四氯乙烯(PCE)的广泛使用和不合理的处置已经使其成为地下水中普遍存在的有毒有害的有机污染物。PCE在厌氧条件下通过还原脱氯发生生物降解,按照非水溶性生物降解模型,有机物先吸附到厌氧活性污泥中,解吸后再进行生物降解。利用间歇试验进行厌养污泥对PCE的吸附降解实验研究。试验结果表明：厌氧污泥对PCE的吸附在0.5 h达到吸附平衡,在1.0 h达到解吸平衡。对实验结果的回归分析表明：PCE的吸附和解吸均符合Freundlich等温吸附方程。厌氧污泥在微生物的作用下将PCE还原脱氯为TCE和DCEs。     

不同共代谢基质下三氯乙烯的厌氧生物降解研究

使用已驯化的厌氧活性污泥,分别以纯牛奶、玉米汁和甲苯作为共代谢基质,对三氯乙烯（ TCE）的降解性能进行对比研究。结果表明：TCE是通过还原脱氯发生降解的;同质量浓度下,甲苯是最佳共代谢基质,纯牛奶和玉米汁相对较差;且在一定范围内,共代谢基质浓度越大,TCE降解效果越好;实验数据的回归结果表明,反应均符合一级动力学。     

铁还原地下水环境中微生物降解苯和甲苯的碳源 专一性分析

文中研究在粒状铁化学还原三氯乙烯渗透反应格栅和生物降解苯和甲苯渗透反应格栅的联合格栅技术中,下游生物降解格栅中铁还原环境下微生物对苯和甲苯的生物降解。通过模拟粒状铁渗透反应格栅下游铁还原环境,主要研究微生物以苯、甲苯作为碳源时,对碳源的专一性。通过批实验发现,对于分别用苯和甲苯培养驯化的微生物,互换碳源后,微生物对2 000.00μg/L苯和甲苯的生物降解半衰期分别由之前的1.0和1.5 d减少到0.7和1.0 d,互换碳源后苯和甲苯的去除率分别增加38%和32%。在粒状铁渗透反应格栅下游生物降解渗透反应格栅中,微生物在铁还原环境下以苯、甲苯作为碳源时对碳源没有专一性,苯和甲苯可以同时被生物降解去除。     

生物降解作用下地下水中TCE、PCE迁移转化的数值模拟研究

根据室内三氯乙烯(TCE)、四氯乙烯(PCE)运移转化的土柱实验和研究区地下水化学特征,建立了研究区微生物作用下TCE、PCE迁移转化的数学模型,并进行了计算机数值模拟,模拟结果与实测值基本一致,表明本次研究建立的数学模型是正确的,研究区地下水中存在生物降解作用,为下一步有机污染的治理提供了科学依据。     

壳聚糖包覆纳米铁镍双金属的迁移性能及其降解地下水中三氯乙烯的研究

地下水中三氯乙烯(TCE)严重威胁公众健康和环境安全,纳米零价铁原位注射技术可以还原降解TCE,但是应用中,纳米零价铁存在易氧化团聚而失活、迁移性差等问题。为此,利用天然高分子壳聚糖作包覆剂增强分散性和稳定性,镍作催化剂增强反应活性,成功制备获得壳聚糖包覆纳米铁镍双金属颗粒(CS Fe Ni)。沉降光谱实验表明包覆壳聚糖后纳米铁的分散稳定性得到增强,Zeta电位测试进一步证实颗粒表面负电荷增加,提高了静电排斥力,使得CS Fe Ni分散稳定性明显改善。柱迁移实验表明改性后的CS Fe Ni迁移能力得到提高。批实验表明CS Fe Ni能够高效降解TCE并能完全脱氯,研究结果为纳米铁原位注射技术的实际应用提供了理论基础和实验参考。     

覆膜态Fe（OH）3在厌氧条件下生物降解苯和甲苯的初探

天然条件下氯代烃的污染经常会与石油烃的污染共存,对于这种混合污染羽的治理,第一步采用粒状铁还原氯代烃,后续利用微生物和第一步产生的副产物生物降解石油烃。苯系物是石油烃中毒性较大、存留时间较长的污染物,本文利用批实验的方法研究了厌氧条件下用Fe(OH)3覆膜于石英砂表面的Fe(Ⅲ)作为电子受体降解苯和甲苯。结果表明,Fe(Ⅲ)作为电子受体时苯和甲苯能够发生厌氧生物降解,经过驯化后苯和甲苯的降解速度明显加快。降解实验表明甲苯的降解速度比苯的降解速度快,苯降解的半衰期是4.02d,甲苯降解的半衰期是3.81d。     

The terrestrial fauna of the Late Triassic Pant-y-ffynnon Quarry fissures,South Wales,UK and a new species of Clevosaurus (Lepidosauria: Rhynchocephalia)

Pant-y-ffynnon Quarry in South Wales yielded a rich cache of fossils in the early 1950s, including articulated specimens of new species (the small sauropodomorph dinosaur Pantydraco caducus and the crocodylomorph Terrestrisuchus gracilis), but no substantial study of the wider fauna of the Pant-y-ffynnon fissure systems has been published. Here, our overview of existing specimens, a few described but mostly undescribed, as well as freshly processed material, provides a comprehensive picture of the Pant-y-ffynnon palaeo-island of the Late Triassic. This was an island with a relatively impoverished fauna dominated by small clevosaurs (rhynchocephalians), including a new species, Clevosaurus cambrica, described here from a partially articulated specimen and isolated bones. The new species has a dental morphology that is intermediate between the Late Triassic Clevosaurus hudsoni, from Cromhall Quarry to the east, and the younger C. convallis from Pant Quarry to the west, suggesting adaptive radiation of clevosaurs in the palaeo-archipelago. The larger reptiles on the palaeo-island do not exceed 1.5?m in length, including a small carnivorous crocodylomorph, Terrestrisuchus, and a possible example of insular dwarfism in the basal dinosaur Pantydraco.     

The effect of water on accessory phase solubility in subaluminous and peralkaline granitic melts

The solubilities of columbite, tantalite, wolframite, rutile, zircon and hafnon were determined as a function of the water contents in peralkaline and subaluminous granite melts. All experiments were conducted at 1035 °C and 2 kbar and the water contents of the melts ranged from nominally dry to approximately 6 wt.% H₂O. Accessory phase solubilities are not affected by the water content of the peralkaline melt. By contrast, solubilities are affected by the water content of the subaluminous melt, where the solubilities of all the accessory phases examined increase with the water content of the melt, up to 2 wt.% H₂O. At higher water contents, solubilities are nearly constant. It can be concluded that water is not an important control of accessory phase solubility, although the water content will affect diffusivities of components in the melt, thus whether or not accessory phases will be present as restite material. The solubility behaviour in the subaluminous and peralkaline melts supports previous spectroscopic studies, which have observed differences in the coordination of high field strength elements in dry vs. wet subaluminous granitic glasses, but not for peralkaline granitic glasses. Lastly, the fact that wolframite solubility increases with increasing water content in the subaluminous melt suggests that tungsten dissolved as a hexavalent species.     

Quaternary stresses revealed by calcite twinning inversion: insights from observations in the Savonnières underground quarry (eastern France)

Calcite samples were extracted both from the rock matrix and the superficial coating of a karstified fault plane of an underground quarry, located in the eastern border of the Paris basin. The karstification is dated as Quaternary. Analysis of mechanical calcite twinning reveals that only the calcite matrix has also undergone a compression trending WNW that can be attributed to the Mio-Pliocene alpine collision. Both coating and matrix have undergone a strike-slip regime with σ₁ roughly trending north–south, that could correspond to the regional present-day state of stress, a strike-slip compression rather trending NNW, modified by local phenomena. To cite this article: M. Rocher et al., C. R. Geoscience 335 (2003).     

HYDROGEOLOGY

正20141756 Chen Ruige(Mathematical College,China University of Geosciences,Beijing100083,China);Zhou Xun Numerical Simulation of Groundwater Level Fluctuation in a Coastal Confined Aquifer with Sloping Initial Groundwater Level Induced by the Tide(Geological Bulletin of China,ISSN1671-2552,CN11-4648/P,32(7),2013,p.1099-1104,6 illus.,16 refs.) Key words:confined water,groundwater level     

METAMORPHIC PETROLOGY

正20141408 Cai Jia(Institute of Geology,Chinese Academy of Geological Sciences,Beijing100037,China);Liu Fulai Petrogenesis and Metamorphic P-T Conditions of Garnet-Spinel-Biotitebearing Paragneiss in Danangou Area,Daqingshan-Wulashan Metamorphic Complex Belt(Acta Petrologica Sinica,ISSN1000-0569,CN11-1922/P,29(7),     

SERIALS

正~~     

GEOPHYSICAL EXPLORATION

正20142386An Guoying(China Aero Geophysical Survey and Remote Sensing Center for Land and Resources,Beijing 100083,China)Application of Satellite Remote Sensing in Regional Hydrogeological Investigation:Taking Cenozoic Strata in Wenquan Sheet(1∶250 000)of Karakoram Range as an Example(Geosci-     

QUATERNARY GEOLOGY & GEOMORPHOLOGY

正20141016An Chengbang(Key Laboratory of Western China’s Environmental Systems,Ministry of Education,Lanzhou University,Lanzhou 730000,China);Zhao Yongtao Lake Records during the Last Glacial Maximum from Xinjiang,NW China and Their Climatic Impli-     

PETROLEUM GEOLOGY

正20141538 Cao Qing(School of Earth Sciences and Engineering,Xi’an Petroleum University,Xi’an 710065,China);Zhao Jingzhou Characteristics and Significance of Fluid Inclusions from Majiagou Formation,Yichuan Huangling Area,Ordos Basin(Advances in Earth Science,ISSN1001-8166,CN62-1091/P,28(7),2013,p.819-828,7 illus.,3 tables,43 refs.)     

GEOCHEMISTRY

正20142002 Wei Hualing(Institute of Geophysical and Geochemical Exploration,Chinese Academy of Geological Sciences,Langfang065000,China);Zhou Guohua Element Content and Mineral Compositions in Different Sizes of Soil in Tongling Area,Anhui Province(Geological Bulletin of China,ISSN1671-2552,CN11-4648/P,32(11),2013,p.1861