直接推进技术在有机污染场地调查中的应用研究

近年来,直接推进技术以其快速精确、经济高效、可装备先进探测器等优点,在国外污染场地调查中得到广泛推广与应用。文章在总结国内外相关研究成果基础上,对直接推进技术中的膜界面探测和连续钻进取样技术在污染场地调查中的功能和应用进行了论述,并在某有机污染场地调查中进行了试验研究。结果表明,利用膜界面探测技术首先半定量获取场地污染物的分布特征及范围,然后以此为指导采用直推式钻机钻进获取代表性样品,并进行实验室测试分析,可以快速、精确地刻画有机污染场地的污染物种类、浓度与分布范围,为后期采样计划和调查提供重要依据。     

地下水污染场地风险管理与修复技术筛选

国际上对于地下水污染场地的控制与修复研究已经取得了许多成果,已有成功的修复实例。我国虽然起步晚,但非常重视地下水污染的防治,开展了全国范围的地下水污染调查,并进行了地下水污染的防治规划。地下水污染的控制与修复已经逐渐进入示范性研究阶段。面对地下水污染场地风险管理的不同方法,以及众多的污染修复技术,如何制定风险管理策略,如何在各种各样的修复技术中筛选合适的技术或技术组合,对于地下水污染场地的防治具有非常重要的意义。笔者分析了发达国家地下水污染风险管理策略,结合在地下水污染场地研究方面的经验,对一些主要的地下水污染修复技术进行了分析论述,提出了考虑污染物特征、场地水文地质条件的地下水污染修复技术的筛选过程和方法。     

浅论地下水污染源强

基于作者对国内外土壤和地下水污染理论、调查技术、风险评价文献资料跟踪,以及对不同类型污染场地调查实践与认识,论述了地下水污染源强的定义、分类、识别及表征方法。从地下水、污染源、地下水污染源、污染源强4个概念入手,给出了地下水污染源强的定义。借鉴污染源分类的思想,对地下水污染源强进行了分类,并提出了采用资料信息收集、现场调查、动态监测、模拟试验等手段识别地下水污染源及源强的思路。初步建立了地面及包气带水相污染源强、地面或近地表固相污染源强、非水相液态污染源强3种地下水污染源强的量化表征方法。     

某石化污染场地含水层自然降解BTEX能力评估

地下水污染问题是国家关注的重要环境问题之一,监测与评估含水层自然降解污染物能力是防治地下水污染的基本手段,也是国外地下水中修复技术研究热点课题。以华北平原某石油化工类场地为案例,通过调查场地水文地质条件、土壤及地下水污染现状,监测场地地下水中苯系物(BTEX)浓度及相关化学参数变化,运用微生物水文地球化学方法和水文地质方法,估算了该场地含水层自然降解苯系物量。这一研究成果为评估我国石油类场地地下水污染的自然修复能力提供了实证和基础数据。     

基于自组织神经网络的污染场地多监测指标相关性分析

为查明场地污染分布特征,需对场地土壤和地下水进行钻探取样,按规范的检测指标进行逐一测试。在初查和详查阶段将获得大量的土壤和地下水污染数据,数据样本数量大、监测指标多,数据结构复杂,如何从场地大数据中提取价值信息已成为研究热点。以某有机污染场地为例,基于自组织映射神经网络（SOM）和K均值算法开展大数据分析,深入探讨地下水和土壤中各污染指标间的相关性。结果表明:（1）基于自组织映射神经网络的大数据分析可快速挖掘复杂多维的污染场地监测数据,有效完成关键信息的提取;（2）地下水中污染检出指标存在显著的聚类特征,同一聚类中的污染指标具备相似的空间分布特征。对场地污染物检测采取先分类后分级的优化筛选策略,减少污染物检测指标数目,从而有效降低场地检测费用;（3）土壤和地下水中污染检出指标存在良好的空间相关性,这与该污染场地地下水渗流速度缓慢有关。土壤和地下水污染检出指标空间分布的相关性,有助于场地污染源的追溯。     

石油类污染场地土壤与地下水污染调查实例分析

以冀中平原某石油类污染场地为例,从污染源分布勘察、场地水文地质模型建立、土壤及地下水的现场调查入手,采用物探、坑探、钻探综合调查技术和定深取样等一些取样方法,对不同深度土壤及地下水的有机污染进行调查和样品分析。结果表明:整个场地的土壤和地下水受到不同程度的污染,30m深度内包气带和饱水带已被污染,50m深度的地下水中有有机污染物检出,石油类场地的污染特征主要表现为土壤及其地下水中含有高浓度单环芳烃和卤代烃。且单环芳烃在土壤与地下水中的浓度高于其它有机污染物。     

中国典型有机污染场地土层岩性和污染物特征分析

目前我国存在大量待修复场地,其分布具有一定的规律性和区域性,场地地层系统结构复杂、渗透性空间异质性显著,污染物种类复杂。总结场地典型土层结构和典型污染物有助于有针对性地开展修复技术的研发。为此,本文收集并整理了全国136处有机污染场地相关资料,对其地域性、地层及污染物特征总结如下:目前我国已经开展调查与修复的有机污染场地主要集中在京津冀和沪宁杭地区;有机污染场地土层基本都含有黏土等低渗透介质,而且都具有非均质性,其中67%场地土层有强非均质性;沪宁杭地区场地土层渗透性总体低于京津冀和辽中南地区,此外我国京津冀和辽中南地区场地调查深度(20.3 m)总体大于沪宁杭地区(12.8 m);我国有机污染场地地下水中最常见的有机污染物种类为氯代溶剂,依次为氯代烷烃类(场地数量占比84%)、氯代苯类(场地数量占比46%)和氯代烯烃类(场地数量占比33%);最常见的3种氯代溶剂依次为二氯乙烷、一氯苯和三氯甲烷。     

生活垃圾对环境的污染评价方法探讨

生活垃圾对环境的污染，主要表现为垃圾渗滤液对地面水、地下水、土壤等的污染。其污染评价涉及污染物指标、污染物标准值的确定和计算模式的建立等内容。本文在总结现行环境指数评价法的基础上，探讨性地提出一套将基于生活垃圾填埋场环境监测技术标准(CJJ／T3037—95)中涉及地面水、地下水、土壤等的相关监测项和垃圾中的其他常见重要污染物，一并确定出的污染评价指标，再根据相关有毒物急性毒性分级，结合阈限值和部分浸出毒性鉴别标准值等分为5类污染指标。并在污染物的标准值确定后，进行对应于5类污染物的不同数学模式计算，得到5个分类污染指数，再比较判别这5个分类污染指数，选出最大者作为总污染指数的组合型评价垃圾污染的方法。经实例应用分析，该方法对各种污染物数据分布情况的适宜性优于现行其他常用方法。     

石油类污染场地的自然衰减作用

在野外石油类污染场地地质、水文地质调查的基础上,对场地地下水中总石油烃的吸附、生物降解等自然衰减作用进行研究。开展了砂质粉土、粉砂、细砂等场地包气带、含水层介质对总石油烃的吸附动力学实验、等温吸附实验、不同矿化度吸附实验、生物降解实验和挥发实验等。实验结果显示,砂质粉土、粉砂、细砂的吸附平衡时间分别为4、7和10 h;通过计算确定了每种介质对总石油烃的等温吸附模型。矿化度对介质吸附总石油烃能力的影响表现为,矿化度越高吸附量越高。生物降解实验结果表明,在场地水土条件下,降解能力最强,且降解符合一级衰减动力学方程。研究表明,地下水受到污染后,吸附、降解、挥发等自然衰减作用对地下水石油类污染物的去除具有非常重要的作用。     

棕地地下水污染修复技术筛选方法研究——以某废弃化工厂污染场地为例

科学合理的地下水污染修复技术筛选方法对于有效修复受污染地下水体、节约修复工程成本、保护地下水资源、维护生态系统安全和人体健康具有重要意义。以某化工厂遗址早期排污渗坑为目标污染源,在结合水文地质勘查和地下水人体健康风险评价的基础上确定场地受污染地下水修复目标污染物,根据污染物迁移性、降解性、人体健康风险等指标及抽出处理、化学修复、生物修复、渗透反应格栅等地下水污染修复技术特点,使用偏好顺序结构评估法(PROMETHEE)进行修复技术筛选。结果显示,该场地地下水中主要污染物为1,2-二氯乙烷、1,4-二氯苯等有机污染物,其中1,2-二氯乙烷在呼吸吸入条件下的最大致癌风险达9.54×10-7。化学清除、监测自然衰减等四项技术适用于该场地地下水1,2-二氯乙烷修复,化学清除法综合排序分值最高,而在成本优先控制条件下,监测自然衰减技术更为适宜。研究对于我国场地地下水污染调查评估及修复工作具有积极的参考意义。     

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.     

Définition d'une limite multicritère ; stratigraphie du passage Campanien–Maastrichtien du site géologique de Tercis (Landes,SW France)Definition of a multi-criteria boundary; stratigraphy of the Campanian–Maastrichtian interval of the geological site at Tercis (Landes,SW France)

Lithostratigraphy, physicochemical stratigraphy, biostratigraphy, and geochronology of the 77–70 Ma old series bracketing the Campanian–Maastrichtian boundary have been investigated by 70 experts. For the first time, direct relationships between macro- and microfossils have been established, as well as direct and indirect relationships between chemo-physical and biostratigraphical tools. A combination of criteria for selecting the boundary level, duration estimates, uncertainties on durations and on the location of biohorizons have been considered; new chronostratigraphic units are proposed. The geological site at Tercis is accepted by the Commission on Stratigraphy as the international reference for the stratigraphy of the studied interval. To cite this article: G.S. Odin, C. R. Geoscience 334 (2002) 409–414.     

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

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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.)