基于有限元法的某稀土矿区地下水污染预测模拟

本文在查明矿区水文地质条件及水质现状的基础上,采用有限元法,对母液集取率为85%与溪沟边水质达标时两种条件下开采过程及开采结束后可能产生的地下水污染进行模拟,以评价不同情景下矿区地下水可能的污染程度。模拟结果表明:在所有开采阶段,稀土矿区附近区域污染物离子以SO24-和NH4+为主,母液回收率85%的工况下水质超标严重,第7年达到最大污染程度;溪沟边地下水水质达Ⅲ类标准时的单井每天的母液泄漏量应小于0.025m3/d,评价区每天的母液泄漏总量约为8.25m3。松散岩类和全风化层地下水易受污染,但其恢复能力较强,下部岩层不容易受到污染,但污染后很难恢复。     

石化企业装置泄漏对地下水污染趋势研究

为研究石化企业不同装置、不同污染物的泄漏对地下水的污染趋势,选取某石化厂区为代表,建立地下水流场模型和污染物运移模型,对不同情形下发生泄漏时污染物对地下水环境的污染趋势进行模拟分析,分析了地下水污染物的产生、入渗途径、扩散方式以及污染趋势。正常工况无防渗情景：原油的渗漏,在厂区：渗漏发生5 a后,潜水含水层原油影响范围0.194 km2,超标范围为0.080 km2,最大运移距离为0.348 km;苯的渗漏,模拟结果显示：泄漏的苯在潜水含水层中13 a后扩散出厂区,厂区下游地下水苯均未超标;二甲苯的渗漏,     

油气终端登陆管线的地下水环境影响评价

在对区域地形地貌、地层岩性、地质构造、水文地质条件等因素调查和综合分析的基础上,针对油气终端登陆管线发生泄漏的情况,开展了地下水环境影响评价。根据滨海地区海陆相交的环境特点,重点分析石油类在地下水中运移至海洋岸线的时间。通过分析工程概况确定管道相关参数,建立预测模型,预测在非正常状况情景下,登陆管线泄漏原油在地下水中不同时间运移预测结果。结果表明：第2944d地下水中石油类 污染物扩散至海岸线,出现检出浓度;第3291d海岸线污染物出现超标现象。为此类项目的地下水环境影响评价和环境风险防范重点提供可参考的实践经验。     

基于GMS的油品泄漏污染模拟及处理措施

研究采用地下水模拟软件（GMS）进行了穿越地下含水层的输油管道泄漏时油品在地下水中的扩散和迁移过程。在模拟出预期的地下流场后，采用溶质迁移模块进行扩散模拟，并成功预测了在特定时期的污染情形和浓度分布。泄漏油品的迁移路径与地下水流动方向基本一致，并且在第1 700 d左右将会汇入最近的河流中造成更大的危害。结合模拟结果和现有的防治措施，分别作了防渗墙和抽出处理的情景模拟，结果显示防渗墙将推迟污染物进入河流的时间，而设置抽水井可以有效处理地下水石油污染。     

基于过程模拟法研究的热电厂地下水污染风险评价

通过对热电厂事故时泄露污染物污染地下水过程的系统分析,构建以观测井作为评价对象对地下水污染进行评价的方法。确定地下水污染风险评价因子,建立污染物基于过程模拟法的迁移转化模型。分别以高锰酸钾指数、石油类污染物及液氨作为水污染风险评价因子对热电厂地下水进行了水污染风险评价。利用建立的热电厂地下水污染风险评价方法,对葫芦岛大唐国际热电厂进行了地下水风险评价。污染源与污染物迁移转化的共同作用决定了地下水污染范围和程度。地下水污染风险评价方法的构建,为热电厂发生事故泄漏时污染物对地下水污染范围和程度的判别提供了有效的监管方法和防治依据。     

页岩气开采致水污染的途径及污染物特点

针对水平钻井和水力压裂技术开采页岩气所产生的水污染问题,基于水文地质学原理,对美国页岩气开采导致水污染的实例及压裂液成分等方面的文献予以分析,对页岩气开采导致水污染的途径及污染物的特点进行研究。结果表明:页岩气开采导致地下水及地表水污染的途径主要包括越流、井筒泄漏及地表人类活动等。页岩气开采长期持续产生水污染物,水污染物种类多、总量大、危害大,某些水污染物难以监测。该研究可以为我国页岩气开采水污染防治标准等规则的制订提供参考。     

矿石淋滤水对地下水污染影响的模拟预测

本文利用地下水数值模拟软件GMS,研究矿石淋滤水对地下水污染的影响。模拟在非正常状况下,矿石经雨水淋滤后,淋滤液中的污染物直接穿透包气带进入地下水运移的情景。经预测,泄漏的污染物铁经过运移后出现短暂超标现象,超标范围未出研究区范围,没有对下游敏感点造成影响。随着时间的推移,污染物在地下水的对流、弥散作用下,污染晕中心浓度逐渐降低,污染晕范围逐渐扩大,直至低于限值。研究成果可为该区的地下水保护措施提供依据。     

油气田开发地下水环境监管面临的形势及对策

根据国家相继出台的《全国地下水污染防治规划（2011—2020年）》、《水污染防治行动计划》等地下水环境监管的法律法规和标准规范要求,分析了油气田开发存在的主要地下水环境风险：采油污水回注/回灌风险,油水井固井中套管损坏等造成的对地下水和土壤的污染,油水管道泄漏风险,固体废物处置设施渗漏风险。提出了在面临新的地下水环境监管形势下,油气田开发应采取的对策与建议：应进行地下水环境质量调查,并将其纳入HSE信息系统管理;建立健全地下水环境监管控制体系;在油气勘探开发中,防范地下水污染;加强开发项目前期地下水环境     

地下水污染物迁移机制及弥散参数初步估计

本文从对流作用、分子扩散和机械弥散作用三方面论述了污染物在地下水中的迁移机制,通过对地下水中水动力弥散尺度效应研究成果的总结和分析,阐述了纵向弥散度与尺度的关系,为地下水污染模型研究提供了一种参数的初步估计。     

多相抽提技术在有机复合污染场地治理中的应用

某工业仓库的空置地块经检测显示,该场地1 000 m2区域地下水受到了不同程度的氯代烃类及二甲苯有机复合污染。运用多项抽提技术治理,即通过真空泵抽提系统强化回收地下6 m深的土壤气体及地下水,并配合废水、废气处理装置来去除地下土壤气体和地下水中溶解态的污染物。经过20 d的可调控抽提运行后,对该区域地下水进行采样检测,结果表明地下水目标污染物浓度均达到了修复目标值。     

Microbial controls on metal mobility under the low nutrient fluxes found throughout the subsurface

Laboratory simulations and field studies of the shallow subsurface have shown that microbes and their extracellular products can influence the mobility of toxic metals from waste disposal sites. Modelling the transport of contaminants in groundwater may, therefore, require the input of microbial ecology data in addition to geochemical data, thus increasing the costs and the uncertainty of predictions. However, whether microbial effects on contaminant mobility occur extensively in the natural subsurface is unknown because the conditions under which they have been observed hitherto are generally unrepresentative of the average subsurface environment. Here, we show that microbial activity affects the mobility of a toxic trace metal (Cu) under the relatively low nutrient fluxes that dominate subsurface systems. More particularly, we show that under these low nutrient conditions, microbes and microbial products can immobilize metal but may themselves be subject to subsequent mobilization, thus complicating the pattern of metal storage and release. Our results show that the capability of microbes in the subsurface to change both the capacity of porous media to store metal, and the behaviour of metal that is released, is not restricted to the well researched environments close to sites of waste disposal. We anticipate our simulations will be a starting point for generating input data for transport models, and specifying the mechanism of metal remobilisation in environments more representative of the subsurface generally.     

Integrated research on subsurface environments in Asian urban areas

The RIHN project "Human impacts on urban subsurface environments" aims to suggest improved development plans of urban centers for human well-being. This will be done by examining reconstructed past changes in urban environments, and by developing integrated nature-social models. Subsurface environmental indicators are developed from the points of view of: (1) human activities; (2) climate change; and (3) character of urban development and social policies. Water, heat, and material environments and transport vectors are being evaluated by a number of different approaches. Some of these include investigating changes in groundwater resources using satellite observations, reconstructing effects of climate change and urbanization using subsurface thermal regimes, and evaluating past contamination patterns from preserved subsurface records. In this overview paper, we describe the current status of urbanization in Asia, subsurface water conditions, material and contaminant transport to surface waters by groundwater, and subsurface thermal anomalies due to the heat island effect. The rapid pace of urbanization in Asia requires that we develop a better understanding of how to deal with environmental impacts, both above and below ground.     

The contribution of human activities to subsurface environment degradation in Greater Jakarta Area, Indonesia

This study examines the factors of human activities causing environmental stresses on the subsurface environments in the urban settings of Jakarta. A major objective of this study is to identify the basin geometry and estimate how critical is the degradation of the subsurface environment within the basin, and it covered micro-palaeontology and chemical analyses, the decrease of water level, and GPS data. New data on shallow groundwater quality is provided and the results indicate strong evidence for human activities have influenced the degradation of the Jakarta subsurface environment.     

Erratum to “Integrated research on subsurface environments in Asian urban areas”

The RIHN project “Human impacts on urban subsurface environments” aims to suggest improved development plans of urban centers for human well-being. This will be done by examining reconstructed past changes in urban environments, and by developing integrated nature-social models. Subsurface environmental indicators are developed from the points of view of: (1) human activities; (2) climate change; and (3) character of urban development and social policies. Water, heat, and material environments and transport vectors are being evaluated by a number of different approaches. Some of these include investigating changes in groundwater resources using satellite observations, reconstructing effects of climate change and urbanization using subsurface thermal regimes, and evaluating past contamination patterns from preserved subsurface records. In this overview paper, we describe the current status of urbanization in Asia, subsurface water conditions, material and contaminant transport to surface waters by groundwater, and subsurface thermal anomalies due to the heat island effect. The rapid pace of urbanization in Asia requires that we develop a better understanding of how to deal with environmental impacts, both above and below ground.     

Impact of longwall mining on groundwater above the longwall panel in shallow coal seams

Since longwall mining causes subsidence through the overlying strata to the ground surface, the surface water and groundwater above the longwall panels may be affected and drained into the lower levels.Therefore, loss or interruption of streams and overburden aquifers is a common concern in coal industry.This paper analyzed the potential effects of longwall mining on subsurface water system in shallow coal seam. In order to monitor different water level fluctuations throughout the mining period, three water wells were drilled down to the proposed deformation zone above the longwall panel. A GGU-SS-FLOW3 D model was used to predict water table contours for the periods of pre- and post-mining conditions. The field data from the three water wells were utilized to calibrate the model. The field test and numerical model can help to better understand the dewatering of shallow aquifers and surface waters related to ground subsidence from longwall mining in shallow coal seam.     

泸定大渡河桥隧道锚边坡稳定性三维数值分析

为了对泸定大渡河悬索桥隧道式锚碇边坡的稳定性进行深入分析,基于坡体结构特征并考虑施工过程,采用FLAC3D数值模拟软件对该边坡在主缆超张拉、暴雨、地震等不同工况下的坡体变形及潜在失稳模式进行了三维模拟分析。结果表明:静力条件下不同缆力对隧道锚边坡浅表层的变形及其失稳破坏模式几乎没有影响,不同缆力作用下浅表层安全系数为1.45;随着缆力的增大,锚碇周围深部岩体安全系数逐渐变小(3.75→3.55→3.2→2.9),且深部岩体潜在滑面与缆力作用线的夹角逐渐变小;除了在地震工况下坡体表面稳定性较差之外,其他工况边坡稳定性、隧道及隧道锚稳定性均较好;隧道、隧道锚及桩基承台的施工对边坡稳定性影响较小,边坡支挡结构的施作有效提高了边坡稳定性。     

Understanding the influence of suspended solids on water quality and aquatic biota

Over the last 50 years the effects of suspended solids (SS) on fish and aquatic life have been studied intensively throughout the world. It is now accepted that SS are an extremely important cause of water quality deterioration leading to aesthetic issues, higher costs of water treatment, a decline in the fisheries resource, and serious ecological degradation of aquatic environments. As such, government-led environmental bodies have set recommended water quality guidelines for concentrations of SS in freshwater systems. However, these reference values are often spurious or based on the concept of turbidity as a surrogate measure of the concentration of SS. The appropriateness of these recommended water quality values is evaluated given: (1) the large variability and uncertainty in data available from research describing the effects of SS on aquatic environments, (2) the diversity of environments that these values are expected to relate to, and (3) the range of conditions experienced within these environments. Furthermore, we suggest that reliance solely upon turbidity data as a surrogate for SS must be treated with caution, as turbidity readings respond to factors other than just concentrations of SS, as well as being influenced by the particle-size distribution and shape of SS particles. In addition, turbidity is a measure of only one of the many detrimental effects, reviewed in this paper, which high levels of SS can have in waterbodies. In order to improve the understanding of the effects of SS on aquatic organisms, this review suggests that: First, high-resolution turbidity monitoring should be supplemented with direct, measurements of SS (albeit at lower resolution due to resource issues). This would allow the turbidity record to be checked and calibrated against SS, effectively building a rating-relationship between SS and turbidity, which would in-turn provide a clearer picture of the exact magnitude of the SS problem. Second, SS should also be characterised in terms of their particle-size distribution and chemical composition. This would provide information to develop a more comprehensive understanding of the observed variable effects of a given concentration of SS in aquatic habitats. These two suggested improvements, combined with lower-resolution concurrent measures of aquatic ecological status, would improve our understanding of the effects of SS in aquatic environments and together with a more detailed classification of aquatic environments, would provide an environment-specific evidence base for the establishment of effective water quality guidelines for SS.     

昆明主城区公园绿地景观生态格局分析

近年来,随着一系列把昆明打造成"面向东南亚、南亚的桥头堡"、"区域性国际城市"的战略部署出台,昆明城市发展又迎来了新的挑战和机遇。实现城市发展目标,需要改变旧有的发展模式,秉承"环境优先"的理念,方能体现科学发展观的思想精髓和实现可持续发展。公园绿地作为城市居民亲近自然、户外活动和科普教育的重要基地,理应受到城市决策者的充分重视。在本文中运用景观生态学理论和定量化的研究方法,对昆明市主城区的公园绿地进行景观生态格局的分析研究,找出目前存在于昆明主城区公园绿地现状及建设管理中的问题,并有针对性地提出对策,以期探求一种协调于城市整体发展的公园绿地生态优化格局。     

Simulation-based process optimization for surfactant-enhanced aquifer remediation at heterogeneous DNAPL-contaminated sites

Widespread use of dense non-aqueous phase liquids (DNAPLs) such as TCE and PCE has resulted in contamination of enormous valuable groundwater resources and become high-priority environmental problems. However, experiences from the past decades have demonstrated that DNAPL-contaminated sites were difficult to investigate and challenging to remediate. In this study, a simulation-based process optimization system was developed through integrating a multidimensional simulator, a multivariate statistical tool and an optimization model within a general framework for supporting decisions of surfactant-enhanced aquifer remediation (SEAR). A 3D multiphase and multi-component subsurface model was first provided to simulate SEAR process; dual-response surface models were then established to build a bridge between remediation actions and system performance; a nonlinear optimization model was then formulated for identifying optimal operating conditions for SEAR operations. The results in simulating a typical PCE spill event and the associated SEAR remediation operations in a heterogeneous subsurface indicated that SEAR would be capable of cleaning up the contaminated aquifer with improved efficiencies and cost-effectiveness compared with direct pump-and-treat actions. The regression-analysis results demonstrated that the proposed dual-response surface models were able to predict system responses under given operating conditions. The optimization results demonstrated that the developed simulation-optimization approach was effective in seeking cost-effective SEAR strategies for DNAPL-contaminated sites. With the developed method, optimum operation conditions under various environmental and economic considerations could be compiled into a database that would supports further studies of on-site process-control with injection and extraction rates being the main control variables.     

基于生态源地与生态廊道优先级评估的生态安全格局构建与优化——以石家庄都市区为例

【目的】构建生态安全格局（ESP）是改善区域生态系统结构和功能,维护生态系统服务的有效措施。近年关于ESP的构建与优化逐渐成为研究热点,但对其中关键因子——生态源地与生态廊道的深入分析仍是一项挑战。【方法】以石家庄都市区为例,基于生态资源综合评价,结合最小累积阻力（MCR）模型构建区域ESP,并根据优先级矩阵,确定其中生态源地与生态廊道的优先级。【结果】结果表明：1）石家庄都市区生态源地的主要用地类型为林地、农田与水体;2）高优先级的生态源地与生态廊道主要集中在西部浅山区与滹沱河沿岸,是需要重点关注与保护的区域。【结论】通过对生态源地与生态廊道优先级排序后进行区域ESP优化,可有效界定区域生态系统维护过程中的关键区域,为未来国土空间规划与生态文明建设深入了解区域生态资源提供助力,并为相应的绿色空间规划提供指导。