Multiple Working Transport Hypotheses in a Heterogeneous Glacial Aquifer System

Multiple working hypotheses can be used to evaluate permissible alternative hydrogeological interpretations at sites with limited subsurface control. This approach was applied to test the viability of three conceptual aquifer system architecture models coupled with three hypothesized source locations for a 1,4-dioxane plume in a heterogeneous glacial aquifer system in Washtenaw County, Michigan. The three alternative conceptual models characterized the site hydrogeology with increasingly complex distributions of hydrostratigraphic units: (A) an effective aquifer, (B) a layered confined aquifer, and (C) a discretely heterogeneous aquifer model. Each was incorporated into an independently calibrated numerical ground water flow (MODFLOW) model. Steady-state and transient flow simulations of the alternative models were evaluated using both hydraulic flow field characteristics observed under natural conditions and the perturbed response after local remedial pumping activity began. Three plausible locations where 1,4-dioxane could have entered the aquifer system were identified using historical information at the site: (1) manufacturing waste water disposal lagoons, (2) a 60 foot (18 m) deep kettle lake, and (3) a shallow impoundment on a local stream. Advective transport modeling (MODPATH) was used to assess the consistency of the hypothesized source locations with observed contaminant migration pathways inferred from the mapped location of the plume. Evaluation of the nine combinations of hydrogeologic conceptualizations and 1,4-dioxane source locations led to elimination of four working hypotheses and discounting of two others, leading to reduced overall uncertainty and the development of new insights into the system behavior.     

Transport and sedimentation of Cu in a microtidal estuary, SE Norway

The transport and sedimentation of copper in the Glomma estuary, SE Norway during a period of 90% reduction in the industrial input of Cu, was studied from sediment trap material and compared to samples of the bottom sediments. Traps were deployed at four stations for several monthly periods during 1990, 1994 and 1995. Trapped material was analysed for suspended particulate matter (SPM), total organic carbon (TOC) and nitrogen (TN), Cu, and Al. Only about 10% of the Cu from the river is trapped in the estuary. Still there was a moderate but significant reduction in Cu concentration in the trap SPM from 1990 to 1994, reflecting the industrial reductions, but only if excluding summer samples apparently influenced by antifouling Cu from boat paint. Settling matter therefore seems appropriate and sensitive for monitoring changes in the Cu load. The results supported the view that TOC is the main carrier of Cu to the sediments.     

Anisotropy in the Ironton and Galesville Sandstones Near a Thermal-Energy-Storage Well, St. Paul, Minnesota

The U.S. Geological Survey is studying the potential for storage of heated water in a sandstone aquifer in St. Paul, Minnesota. The efficiency of the aquifer to store thermal energy is related, in part, to the hydrogeologic characteristics of the aquifer. The movement of heat away from the injection well is directly related to the anisotropy. Aquifer tests were conducted to determine the anisotropy near the heated-water injection well. The maximum and minimum values of transmissivity along the principal directions of the hydraulic conductivity tensors of the Ironton and Galesville Sandstones in St. Paul, Minnesota are approximately 1,090 and 480 feet squared per day. The storage coefficient is 4.5 × 10⁻⁵. These values represent the average of four determinations of nonsteady flow to a well in an idealized infinite anisotropic aquifer. Analysis of the values of transmissivity and storage coefficient for hypothetical changes in location of two of the monitoring wells where depth-deviation surveys were not available indicates that computed transmissivities vary less than 5 percent and storage coefficients vary less than ±6 percent.     

Textural,geochemical and mineralogical evidence for the origin of peoria loess in Central and Southern Nebraska,USA

Possible sources of Peoria loess in central Nebraska have been investigated through the fingerprinting of the textural, geochemical and mineralogical characteristics of the loess and possible source sediments, with statistical comparison of the textural and compositional fingerprints. The results of the investigation contrast with the ‘desert loess’ model proposed by Lugn (1960), and are instead consistent with the derivation of the Peoria loess in Nebraska primarily from fluvio-glacial outwash sediments carried by the ancestral North and South Platte River systems from the Rocky Mountain Front Ranges during the late Pleistocene.     

Injury and Environmental Epidemiology, a converging agenda

Reliance on motor vehicle travel and the internal combustion engine has provided mobility, but the public health costs are substantial: Road deaths, adverse deleterious health effects from air pollution and noise, reduction in physical exercise, and toxic hazards associated with the refining, transport, use and disposal of petrochemicals. For traumatic road injury, kinetic energy is the pathogen. Risks for injury and death rise with the second and fourth power of increases in velocity upon impact; emissions of many air pollutants also increase exponentially with speed. Models derived from vector transmission in infectious diseases have proven useful for defining risks and designing interventive strategies. These models predict the number of lives saved and injuries prevented from a package of low-cost, effective measures, which can be quickly implemented. Eradication of road deaths and elimination of air pollution emissions are achievable public health goals. Speed camera systems produce sustainable levels of detection deterring speeding, and thereby reducing human injury and environmental damage. “Education” and building more roads, part of the scenario “predict and provide,” have not been shown to reduce injury risks. Building more roads, which in the long run, promotes urban sprawl and congestion, does not reduce travel time. High speed toll roads and circular beltways, which involve trade-offs among time-saving, risk of injury, and diversion of traffic from population centers, need to be re-evaluated and compared to alternative strategies based on modal shifts. We suggest that revenues resulting from massive use of speed cameras can serve as the first step for funding the first steps of sustainable transportation policies based on developing alternatives to private vehicle use and trucking. Such alternatives could lead to even further reductions in injury and death and adverse effects of air pollution. More involvement by epidemiologists in overseeing and evaluating strategies can expedite progress towards the goal of eradication of deaths from road injury, and at the same time, reduce emissions of air pollutants. This revised version was published online in July 2006 with corrections to the Cover Date.     

Magnetpartikel-Enzymimmunoassay als schnelle Screening-Methode zur Bestimmung von Atrazin in Umweltproben Magnetic Particle Based Enzyme Immunoassay as a Rapid Screening Method for the Analysis of Atrazine in Environmental Samples

The use of a magnetic particle based enzyme immunoassay for the analysis of atrazine is presented. The scope of the test is between 0.04 and 5 ppb. The assay is easy to perform and the results are obtained in less than an hour. Coefficients of variation below 10% were achieved. Soil and water samples were analyzed, the latter ones without clean-up. No interferences of the sample matrices could be found. Comparison of atrazine concentrations determined by the magnetic particle based assay, a microtitre plate assay, and GC showed good correlations. The presented assay can be used as a rapid and sensitive screening method for water and soil samples.     

Environmental Risk and Environmental Damage to Surface Water Quality: Topicality,Terminology, Quantitative Estimates

The concepts of environmental risk and environmental hazard to surface water quality are discussed. The interpretation of these concepts in different countries is analyzed and a list of more exact terms and definitions regarding these concepts is proposed. A method for estimating the environmental risk and environmental damage to surface water quality is developed. Possible applications of the estimated environmental risk and environmental hazard for surface water quality management are discussed.     

漏阈值系统的自组织临界性: 近平均场的动力学影响及其对地震、神经生物学和预测方面的意义

阈值系统被看作是自然界中某些最重要的非线性自组织系统,包括地震断层系统、神经网络、超导和半导体、互联网以及政治、社会和生态系统。所有这些系统都具有与时、空、强相关的动力学,且都典型地显示了时空尺度的多重性。我们在两种不同尺度上讨论地震阈值系统自组织的物理学问题：(1)“微观”的实验室尺度,来自模拟结果的考虑导致了动力学方程,这些方程可以推导从滑动实验中得到的结果;(2)“宏观”的地震断层系统尺度,强相关地震断层系统的物理学可以通过应用定义在希尔伯特本征态空间有关的态向量来理解。所有的这些系统中,长程相关导致局部各态历经动力学的存在。耗损效应的存在导致了“漏阈值”动力学的出现,它等同于一个控制与背景涨落尺度有关的成核事件尺度的新的标度场的出现。在宏观地震断层尺度的框架下,这些作为一种预报未来地震活动方法的观念显示出了比较大的希望。     

GPS数据处理方面的最新进展及其对定位结果的影响

简要介绍目前国际上在GPS数据处理方面取得的一些主要进展,包括各种模型的精化、相位模糊度的求解方法、全球参考框架的更新,等等。这些变化无疑会提高定位的精度和可靠性。同时,相对于原模型、方法、框架,其影响也可能是系统性的,在将GPS定位结果应用于地壳形变分析时尤为值得关注。     

Environmental Emission of Mercury During Gold Mining by Amalgamation Process and its Impact on Soils of Gympie, Australia

— The aims of this study were to estimate the total amount of mercury released to the environment during 60 years of gold mining (1867–1926) at Gympie, Queensland, Australia and to measure the mercury levels in soil samples surrounding the mining activity. We estimated that 1902 tonnes of mercury was released to the environment and about 1236 tonnes of which was released to the air. The mean mercury in the soil samples in the vicinity of the Scottish battery varied from 1.07 to 99.26 μg g^?1 as compared to 0.075 μg g^?1 as background mercury concentrations. The maximum mercury concentration measured in sediments of the Langton Gully was 6.12 μg g^?1. These results show that large amount of mercury was used in this area during gold mining. Since mining is active in the area and Langton Gully flows into Mary River, we therefore, recommend that mercury concentration in air and fish should be monitored.     

风切变对飞行的影响及其预报时效分析

利用NCEP再分析资料和AMDAR资料,对2008年11月1日首都机场冷锋过境前后风切变现象及其可预报时效进行分析。分析认为:在冷锋过境前后,首都机场存在多种形式的风切变,有高空槽前后的水平风切变、高层和中层急流轴引起的水平风切变、冷锋前逆温层顶上下的水平风切变和地面锋面过境时跑道面上的水平和侧风切变。对各种风切变的可预报时效进行了分析。     

Transport in fracture processes: Fragmentation and slip

We present a new development in the asymmetric continuum theory with the shear oscillations (twist motions) and independent spin; these motions (displacement velocities and spin) can be shifted in phase to describe the independent rebound processes. Our approach provides an extension of the asymmetric continuum theory by including the microfragmentation processes with a double transport which may appear in an advanced fracture process under very high load. The related nonlinear equations, leading to soliton solutions, are derived.