Remediation of NAPL source zones: lessons learned from field studies at Hill and Dover AFB

Innovative remediation studies were conducted between 1994 and 2004 at sites contaminated by nonaqueous phase liquids (NAPLs) at Hill and Dover AFB, and included technologies that mobilize, solubilize, and volatilize NAPL: air sparging (AS), surfactant flushing, cosolvent flooding, and flushing with a complexing-sugar solution. The experiments proved that aggressive remedial efforts tailored to the contaminant can remove more than 90% of the NAPL-phase contaminant mass. Site-characterization methods were tested as part of these field efforts, including partitioning tracer tests, biotracer tests, and mass-flux measurements. A significant reduction in the groundwater contaminant mass flux was achieved despite incomplete removal of the source. The effectiveness of soil, groundwater, and tracer based characterization methods may be site and technology specific. Employing multiple methods can improve characterization. The studies elucidated the importance of small-scale heterogeneities on remediation effectiveness, and fomented research on enhanced-delivery methods. Most contaminant removal occurs in hydraulically accessible zones, and complete removal is limited by contaminant mass stored in inaccessible zones. These studies illustrated the importance of understanding the fluid dynamics and interfacial behavior of injected fluids on remediation design and implementation. The importance of understanding the dynamics of NAPL-mixture dissolution and removal was highlighted. The results from these studies helped researchers better understand what processes and scales are most important to include in mathematical models used for design and data analysis. Finally, the work at these sites emphasized the importance and feasibility of recycling and reusing chemical agents, and enabled the implementation and success of follow-on full-scale efforts.     

Chemo- and Biostratigraphy of the Jurassic Oil Shales from the Qiangtang Basin, Northern Tibet, China: A Case Study of the Toarcian Oceanic Anoxic Event

The marine oil shales of the Qiangtang Basin, northern Tibet, exposed in the Biluo Co, Tuonamu, Shenglihe and Changsheshan areas are believed to be important petroleum source rocks. This work comprehensively analyzed the carbon isotopes, trace elements, and calcareous nannofosills, ammonites and bivalves of the Biluo Co section in the Qiangtang Basin. The organic carbon isotopes show a positive excursion close to 2.17‰(relative to PDB), which, albeit significantly smaller, may also be associated with other Early Toarcian Oceanic Anoxic Events(T-OAE) in the European epicontinental seas and the Tethyan continental margins. Coinciding with the Early Toarcian transgression, the oxygen deficiency in bottom water had led to dysoxic-anoxic conditions and deposition of black shales lacking benthic fauna. Under such condition, the redox-sensitive trace metals such as Mo, V, Ni, Cr, and U were enriched, in conjunction with high planktonic productivity of Watznaueriaceae calcareous nannofossils. Comparison of the results with the records of chemo-and biostratigraphy, as well as the palaeogeography during the Early Jurassic suggests that the anoxia linked to the Early Toarcian oceanic anoxic event was mainly caused by the high surface water temperature, sea-level rise and an increase of surface water productivity.     

Inorganic species in geologic fluids: correlations among standard molal thermodynamic properties of aqueous ions and hydroxide complexes

Correlations among experimentally determined standard partial molal thermodynamic properties of inorganic aqueous species at 25 degrees C and 1 bar allow estimates of these properties for numerous monatomic cations and anions, polyatomic anions, oxyanions, acid oxyanions, neutral oxy-acid species, dissolved gases, and hydroxide complexes of metal cations. Combined with correlations among parameters in the revised Helgeson-Kirkham-Flowers (HKF) equation of state (Shock et al., 1992), these estimates permit predictions of standard partial molal volumes, heat capacities, and entropies, as well as apparent standard partial molal enthalpies and Gibbs free energies of formation to 1000 degrees C and 5 kb for hundreds of inorganic aqueous species of interest in geochemistry. Data and parameters for more than 300 inorganic aqueous species are presented. Close agreement between calculated and experimentally determined equilibrium constants for acid dissociation reactions and cation hydrolysis reactions supports the generality and validity of these predictive methods. These data facilitate the calculation of the speciation of major, minor, and trace elements in hydrothermal and metamorphic fluids throughout most of the crust of the Earth.     

澳洲普洛斯本河现代沉积物环境地球化学研究

本文通过对澳洲普洛斯本河现代沉积物的粒度，营养元素和微量金属元素地球化学分布及其季节性差异的研究，探讨了河流沉积物环境的地球化学的研究方法，阐述了河流现代沉积物的污染现状和规律，为河流的评价和环境治理等提供了重要的科学依据。     

The use of the deposit-refund framework in port reception facilities charging systems

The European Union set in place Directive 2000/59/EC with the aim of substantially reducing discharges of ship-generated waste into the sea by improving the availability and use of port reception facilities. According to the Directive, port administrations shall ensure that the cost recovery system must aim to discourage ships from discharging their waste into the sea, while simultaneously placing the burden of costs on ships, in line with the "polluter pays principle". The present paper examines the extent to which the deposit-refund framework could be used in charging systems of port reception facilities. This has been realized through a case study involving a Greek port. Specifically, the charging system proposed here seems to approach quite close to the primary target, i.e. to a charging system that motivates ships to act more environmentally responsible manner regarding their waste, without significantly affecting their total cost nor the competitiveness of the port.     

碳汇效应及其影响因素研究进展

碳中和现已成为全球共识。为实现碳中和目标,除了发展新能源降低碳排放外,提升固碳增汇能力是其重要途径。碳汇可分为海洋碳汇和陆地碳汇两大类。海洋碳汇包括沿海生态碳汇、海水生态碳汇和人工海洋碳汇。其中,沿海生态碳汇主要由海岸植被固碳效应和沿海沉积物负载形成,海水生态碳汇主要由海洋碳泵效应形成,这两种碳汇与季风洋流条件、陆源有机物输入、海岸地理条件和人为活动直接相关,人工海洋碳汇的可行性需要综合考虑对海洋生态的影响。陆地碳汇包括陆地植被碳汇、自然地质碳汇和人工地质碳汇。其中,陆地植被碳汇是通过森林植被、草地植被以及湿地植被等植物的光合作用实现,受气温与降水、大气成分、土地利用变化以及自然干扰等因素的影响。自然地质碳汇主要由土壤碳汇和岩石风化碳汇组成,土壤碳汇受区域植被条件、气候条件和土壤利用等因素影响,而碳酸盐岩和硅酸盐岩风化作用吸收大气CO₂的岩石风化碳汇主要受气温、降水、岩石类型、水文条件以及人类活动的影响。人工地质碳汇是将捕集后的CO₂注入地下指定区域进行长期封存形成,其封存能力受地质构造、储盖条件、地热、地层水动力、油气潜力和盆地勘探开发程度...     

贵州中、下寒武统界线层型候选剖面地球化学特征研究

在贵州台江八郎凯里组中，下寒武统界线层型候选剖面上，对中，下寒武统界线剖面沉积岩地球化学特征进行了研究，发现沉积岩中的微量元素含量和稀土元素分布模式沿剖面的变化均具有规律性，元素反映的沉积环境也具有类似特点，剖面微量元素及稀土元素地球化学特征在界线剖面12－13层之间变化明显，突变点主要分布在这两层样品中，因此，将八郎界线剖面上中，下寒武统界线置于剖面12－13层之间。     

地面沉降对河道堤防的影响及应对措施

地面沉降已经发展成为天津市的主要地质灾害之一,不均匀的地面沉降已经给天津市河道堤防的安全造成了威胁,部分堤段已经出现了裂缝、漏洞等险情。为有效控制堤防工程的地面沉降,以海河干流堤防和蓟运河下游堤防为例通过对长序列的地面沉降数据进行分析,阐述了地面沉降对河道堤防造成的影响,并针对地面沉降对堤防工程造成的破坏提出相应的治理措施,保障工程的功能效应,减小堤防工程因地面沉降而产生的经济损失。