bluuebunny/crossref_metadata_2025_split huggingface dataset:
Groundwater and Cadmium: Chemical Behavior and Treatment
Authors: Jacobs James A. , Foreman Craig 
Published: July 2005

Abstract
Cadmium occurs naturally in ores containing other elements such as oxygen (cadmium oxide), sulfur (cadmium sulfate, cadmium sulfide), and chlorine (cadmium chloride) or compounds (cadmium carbonate). Cadmium is usually extracted during the production of other metals such as zinc, lead, and copper. A primary use for cadmium is in rechargeable nickel–cadmium and solar batteries, which are sold worldwide. Cadmium does not corrode easily and is also used in metal plating and coating operations including transportation equipment and various industrial machinery as well as plastics manufacturing. It is used in numerous pigments, in baking enamels, and in photographic processes as well as in television and monitor screen phosphors. Cadmium is released into the environment through industrial waste streams and landfills. Cadmium is relatively mobile in surface and groundwater and has a United States Environmental Protection Agency (U.S. EPA) Maximum Contaminant Level Goal (MCLG) of 5 parts per billion (ppb) in drinking water (1). The World Health Organization has set the provisional tolerable daily intake of cadmium at 60–70 µg/day (2).
Groundwater and Cobalt: Chemical Behavior and Treatment
Authors: Jacobs James A. , Walter Lise 
Published: July 2005

Abstract
Cobalt has been used for about 5000 years. Cobalt metal is produced as a by‐product of copper, nickel, and lead production. It is not economically feasible to isolate cobalt. Cobalt is important for use in the commercial, industrial, and military sectors. Most cobalt remediation projects occur near mines. All of the main aqueous species of the metal contain cobalt in the +2 oxidation state. Cobalt is most hazardous to the human respiratory system. Conventional remedial methods include soil excavation and groundwater extraction and treatment. Newer methods of remediation include phytoaccumulation and geochemical fixation with pH adjustment.
Groundwater and Lead: Chemical Behavior and Treatment
Authors: Jacobs James A. , Kirkland Lisa 
Published: July 2005

AbstractLead (Pb) occurs naturally in the earth's crust and is reported as being the most abundant among the heavy metals, with the average Pb content of the crust ranging from 13 to 16 parts per million (1). Lead has a crustal abundance of 1.4 × 101 mg/kg, with an estimated oceanic abundance of 3 × 10−5 mg/L (2). Lead makes up 0.013% of the earth's crust. There are more than 200 minerals of Pb. Natural mobilization of Pb into the environment occurs mainly from the erosion of Pb‐containing rocks and via gaseous emissions during volcanic activity. Lead is mined and refined easily. On a worldwide basis, most lead is concentrated by roasting galena, also called lead sulfide (PbS), in hot air. Nearly one‐third of the consumption in the United States is obtained by recycling efforts (2).
Groundwater and Nitrate: Chemical Behavior and Treatment
Authors: Jacobs James A. , Geddes‐McDonald Lorraine 
Published: July 2005

Abstract
Nitrate is a naturally occurring substance, which is an essential ingredient for the growth of plants. Human activities can contribute to higher levels of nitrate in the ground and surface waters. The major source of excess nitrogen is nitrate fertilizers for agricultural, lawn, and other garden uses. Nitrates are sourced from nitrates in nitrate fertilizers, the storage or use of animal manure, leaky septic systems, leaky sanitary sewer pipelines, and improper disposal of treated wastewater containing high nitrate levels. Through storm runoff and leaching processes, nitrates have become dissolved in stormwater runoff or infiltration waters. These sources of dissolved nitrates have created significant impacts on worldwide surface water and groundwater resources.
Groundwater and Perchlorate: Chemical Behavior and Treatment
Authors: Jacobs James A. , Dwyer Shonel 
Published: July 2005

Abstract

Large‐scale perchlorate production began in the 1940s. Perchlorate leakage has been ongoing in some cases for decades. The majority of perchlorate spills are related to the use of explosive propellant as a solid rocket fuel for missiles and for the NASA space shuttle. It has only been since the late 1990s, when laboratory methods improved detection of perchlorate in the groundwater, that the full impact of the groundwater contamination became evident. A variety of point of use treatments for perchlorate are available, at varying efficiencies and costs. Of the various
in situ
technologies, anaerobic bioremediation is the most promising for widespread subsurface perchlorate treatment.
Groundwater Balance
Authors: Kumar C. P. 
Published: July 2005

Abstract
Water balance techniques have been extensively used to make quantitative estimates of water resources and the impact of man's activities on the hydrologic cycle. On the basis of the water balance approach, it is possible to make a quantitative evaluation of water resources and its dynamic behavior under the influence of man's activities. In this article, an attempt has been made to describe the methodologies to understand and evaluate the various recharge and discharge components of groundwater balance equation and to establish the recharge coefficient with a view to work out the groundwater potential of an area.
Phytoremediation Enhancement of Natural Attenuation Processes
Authors: Vance David B. , Jacobs James A. 
Published: July 2005

Abstract
Phytoremediation is a remediation method that uses what is in essence enhanced natural attenuation for cleanup. There are a variety of phytoremediation methods, some having multiple names: phytostabilization, rhizodegradation (phytostimulation, rhizosphere bioremediation, or plant‐assisted bioremediation), rhizofiltration (contaminant uptake), phytodegradation (phytotransformation), phytovolatilization, and Phytoaccumulation (phytoextraction or hyperaccumulation). Various types of plants can be used in phytoremediation, including poplar trees, alfalfa, black locust, Indian mustard, fescue grass, crested wheatgrass, and Canada wild rye.
River‐Connected Aquifers: Geophysics, Stratigraphy, Hydrogeology, and Geochemistry
Authors: Al Tom A. , Macquarrie Kerry T. , Butler Karl E. , Nadeau Jean‐Christophe , Dawe Melissa R. , Amskold Larry 
Published: July 2005

Abstract
Pumping of water from wells constructed in aquifers adjacent to a river commonly causes infiltration of river water toward the wells, thereby increasing the total available water yield. This type of water production has been used extensively in many European countries and, to a lesser extent, in North America. The flow of river water through permeable riverbed and aquifer sediments, commonly referred to as riverbank filtration, can provide filtration and general purification benefits. Some of the most important considerations in managing aquifer systems of this type include the stratigraphic controls on the flow path and infiltration flux for river water entering the aquifer, the travel time between the river and the pumping wells, and the spatial and temporal variations in geochemical reactions that occur as river water infiltrates the aquifer, leading to changes in water quality.
In this contribution, the Fredericton Aquifer, which is considered typical of many alluvial‐valley water‐supply aquifers, is used as a case study to illustrate possible approaches to the characterization of river‐recharged aquifer systems, and to describe some of the important stratigraphic, hydrogeologic, and geochemical features of these systems. The combined use of geophysical, hydrogeological, and geochemical methods of investigation has led to a more complete understanding of river water infiltration toward municipal wells and the resulting water quality implications.
Groundwater— Nature's Hidden Treasure
Authors:   Environment Canada
Published: July 2005

Abstract
It is sometimes thought that water flows through underground rivers or that it collects in underground lakes. Groundwater is not confined to only a few channels or depressions in the same way that surface water is concentrated in streams and lakes. Rather, it exists almost everywhere underground. It is found underground in the spaces between particles of rock and soil, or in crevices and cracks in rock. The water filling these openings is usually within 100 metres of the surface. Much of the earth's fresh water is found in these spaces. At greater depths, because of the weight of overlying rock, these openings are much smaller, and therefore hold considerably smaller quantities of water.
Groundwater flows slowly through water‐bearing formations (aquifers) at different rates. In some places, where groundwater has dissolved limestone to form caverns and large openings, its rate of flow can be relatively fast but this is exceptional.

Many terms are used to describe the nature and extent of the groundwater resource. The level below which all the spaces are filled with water is called the
water table
. Above the water table lies the
unsaturated zone
. Here the spaces in the rock and soil contain both air and water. Water in this zone is called
soil moisture
. The entire region below the water table is called the
saturated zone
, and water in this saturated zone is called
groundwater
.
Hydrologic Feasibility Assessment and Design in Phytoremediation
Authors: Weaver J. W. , Mccutcheon S. C. , Hutchinson S. L. 
Published: July 2005

AbstractSeveral design considerations for phytoremediation are based on the capability of trees to remove contaminated water from aquifers. These capabilities depend upon the amount of water that can be withdrawn, the vertical distribution of contaminants, and flow patterns in the aquifer. For each of these, an example field site is given where methods were applied to quantify the characteristics. These include a model of forest evaporation for estimating the balance between precipitation and evapotranspiration, a simple model of recharge‐driven plume diving, and the use of groundwater flow modeling for assessing various features of the groundwater flow.
Finite Element Modeling of Coupled Free and Porous Flow
Authors: Hanspal Navraj S. , Waghode Atul N. , Das Diganta Bhusan 
Published: July 2005

AbstractIn this article, the finite element method will be discussed in the context of solving coupled free and porous flow governed by Navier–Stokes and Darcy equations, respectively. Boundary conditions that may be used for simulating coupled flow problems are also discussed very briefly.
Geophysics and Remote Sensing
Authors: Jansen John R. 
Published: July 2005

Abstract
When data cannot be gathered by direct observation, such as observing an outcrop or taking a physical sample, information can often be obtained by using remote sensing techniques. Remote sensing methods measure physical properties of materials by measuring changes in the flux of various forms of energy using natural or transmitted fields. The science of applying these methods to earth materials is called geophysics

Geophysics is commonly used to obtain subsurface information for a variety of resource development and engineering applications. A partial list of applications for which geophysical methods can be used includes mapping aquifers, mapping water quality, mapping geologic structure, measuring flowing fluids, finding buried objects for engineering and archeological purposes, and measuring
in situ
soil and rock properties. The major energy fields used include magnetic fields (magnetometry), electrical fields (electrical resistivity and spontaneous potential), electromagnetic fields (electromagnetic induction and ground‐penetrating radar), propagation of seismic waves (seismic reflection, seismic refraction, passive acoustic emission monitoring, and spectral analysis of surface waves), the gravitational field (gravimetry), gamma‐ray radiation (gamma‐ray spectroscopy), and heat transfer (geothermal). Other physical properties can be measured by bombarding the material with gamma rays (electron density) or high‐energy neutrons (hydrogen content). Less commonly, properties such as thermal conductivity, electrical chargeability, or magnetic resonance are also measured.
Groundwater Velocities
Authors: Babel Mukand Singh 
Published: July 2005

Abstract
Groundwater flows through interconnected pore spaces in subsurface soil in response to differences in fluid pressure and elevation. Groundwater flow rates are extremely slow, compared to surface water, and they are also highly variable. For example, in clayey soils, groundwater moves as slowly as a fraction of a millimeter per day; however, in sandy soils, it moves faster, even up to more than a meter per day. Hydrology is concerned with both the speed and the direction of groundwater movement. Groundwater velocity is very important in dealing with contaminant migration and arrival time, mass flux, site characterization, reactive barrier design, and calibration of transport processes.
Groundwater Flow and Transport Process
Authors: Almasri Mohammad N. , Kaluarachchi Jagath J. 
Published: July 2005

Abstract
Groundwater is the primary source of drinking water in many parts of the world and the sole supply of potable water in many rural communities. Due to population growth over time, there is an increasing stress on groundwater resources to meet the growing demand for freshwater, especially in arid and semiarid regions where drought conditions may prevail. In addition, protection of the quality of groundwater resources is very important considering the diversity of potential pollution sources. As such, it is essential for efficient use, effective management, and protection of groundwater resources to understand and comprehend basic groundwater flow concepts and fundamental transport processes of contaminants. This study present a general outline of the main concepts of groundwater flow and transport processes. This includes the vertical distribution of subsurface water; Darcy's law; aquifer types; sources and types of groundwater contamination; contaminant transport via dispersion, advection, and diffusion; physical governing equations; and mathematical modeling.
Groundwater and Arsenic: Chemical Behavior and Treatment
Authors: Vance David B. , Jacobs James A. 
Published: July 2005

AbstractArsenic is not an abundant element in the earth's crust; the average crustal concentration of arsenic is 1.8 mg/Kg (1) to 5 mg/Kg (2). Arsenic ranks as the 52nd element in abundance, between tin and molybdenum (1). However, through geogenic processing of crustal materials, arsenic can be concentrated in soils to a typical range of 2 to 20 mg/Kg (3) to 1 to 50 mg/Kg (2), with concentrations as high as 70 mg/Kg being unremarkable (3). Human activity generates anthropogenic arsenic, which makes it the third most common regulated inorganic contaminant found at U.S. Superfund sites.Arsenical copper was in use by 4000BC, and the toxic effects of arsenic were documented by early Greek writers. More recently, arsenic has been linked to skin, bladder, and other cancers (4). The U.S. Environmental Protection Agency (USEPA) lowered the arsenic standard in drinking water from 50 µg/L to 10 µg/L, effective January 23, 2006.Modern usage of arsenic includes formulation of pesticides and herbicides, decolorization of glass, paint manufacturing, the production of semiconductors, and the treatment/preservation of wood. Pressure treated lumber was commonly treated for decades using copper‐chromium‐arsenate (CCA). This product, also called “green wood,” has been used for foundation lumber and more recently as wood for outdoor children's play structures and picnic tables. The CCA wood is being phased out for toxicity concerns and environmental reasons. Many of the pressure treatment lumber facilities have significant soil and groundwater contaminated with arsenic as well as chromium.
Groundwater Vulnerability to Pesticides: An Overview of Approaches and Methods of Evaluation
Authors: Loague Keith , Corwin Dennis L. 
Published: July 2005

AbstractThe word pesticide is a general term used to refer to the chemicals that are employed to control pests. In many areas of the world, successful agriculture depends on both pesticides and irrigation. The combination of repeated pesticide applications and irrigation over large nonpoint source areas often leads to leaching through the vadose zone and, subsequently, to groundwater contamination. For effective regulation and/or remediation, it is important to assess the vulnerability of valuable groundwater resources to contamination from widespread pesticide applications. The use of mathematical models for assessing groundwater vulnerability fills information gaps, identifies critical areas and pesticides for future monitoring, and provides the “what if” capability needed for both regulation and remediation. The uncertainty in chemical, climatic, and soil databases must be considered in assessing the vulnerability of groundwater to contamination from pesticides. Results from the Fresno case study, for the DBCP groundwater contamination problem in California's San Joaquin Valley, are discussed. The objective of the Fresno case study was to determine, from a simulation perspective, if label recommended nonpoint source applications were likely to be the principal source of the DBCP groundwater contamination in Fresno County. The relatively unique characteristic of the Fresno case study is that both the unsaturated near surface and the saturated subsurface were considered.
Head
Authors: Rasmussen Todd 
Published: July 2005

Abstract
The forces that cause water movement can be combined into a single measure, called the head, so that water moves from higher to lower head. This concept unites all forces (such as gravity, pressure, momentum, osmotic) so that predictions about the direction and magnitude of fluid movement can be obtained. Observations of head within aquifers are routinely used by scientists to develop a water table map in unconfined aquifers and potentiometric maps in confined aquifers. In many cases, the observed water levels in observation wells become a direct measure of head. Problems may develop, however, when the water density in the observation is not fresh. In these cases, a conversion to freshwater head is needed. Another difficulty develops when water levels change over time, such as when barometric pressure and precipitation cause short‐term fluctuations.
Laminar Flow
Authors: Hanspal Navraj S. , Sharma Raj 
Published: July 2005

Abstract
The prime objective of this text is to describe the elementary concepts involved in laminar fluid flows. In general, any flow is characterized by the continuous deformation of fluid particles and a corresponding internal state of stress. It has been experimentally established that, under laminar situations, the rate of deformation is directly proportional to local viscous stress. Laminar flows thus fall under the category of viscous flows. The principle laws that govern the motion of fluids are also discussed.
Leaching
Authors: Kelley David W. 
Published: July 2005

Abstract
Leaching is the phenomenon whereby a liquid (usually water) moves through a matrix (usually soil) from one location to another (usually downward with gravity), dissolving or suspending materials along the way. The liquid that migrates is referred to as leachate, and contains a mix of dissolved and/or suspended ions or compounds. These materials are either natural or anthropic and include dissolved salts, fertilizers, soluble minerals, organic materials, plant nutrients, or natural or synthetic chemicals. Leaching is affected by the amount, rate, direction, and quality of the leachate. Leachate movement is influenced by the hydraulic conductivity of the matrix, presence of impeding layers (aquitards or aquicludes), antecedent soil water content (saturated vs. unsaturated flow), osmotic or matric potentials, water holding capacity of the soil, and macropore flow. Leaching is governed by the processes of mass flow, diffusion, dispersion, sorption, and degradation. Leaching rates are highest in humid regions or on land under irrigation, and lowest in arid or permanently frozen regions. Most non‐industrial leaching occurs on agricultural land or under antiquated or modern landfills. Leaching accounts for the bulk of non‐point source pollution to groundwater, and subsequently to any surface water to which it is hydrologically‐connected.
Metal Organic Interactions in SubtitleDLandfill Leachates and Associated Ground Waters
Authors: Gonçalves Mário Abel 
Published: July 2005

AbstractLandfills are important facilities for proper waste disposal in modern societies, but have some environmental problems. These are mostly due to leachate spilling and releasing through surface and groundwaters. Because organic compounds are the most important constituents of these leachates and have a wealth of reactive functional groups, their interaction with metals is of utmost importance to understand the mobility and bioavailability of these metals in the environment. Metal‐organic interaction is mostly characterized by complex formation and stability. Predicting metal‐organic complex stability is however, a difficult task, but the electronic configuration of metal cations may provide some insight on that problem based on the classification into hard‐ and soft‐sphere cations. On the other hand, landfill leachates are complex solutions where these interactions are likely to occur with a wide range of organic compounds, rendering individual interactions almost irrelevant. Besides, the number of cations studied in this particular environment is limited to Cu, Ni, Zn, Cd, Pb, and Cr. What has been shown is that, depending on the cation, they may be predominantly associated with colloidal and/or dissolved organic matter, in particular forming chelates with the organic compounds, or forming inorganic complexes as well as insoluble solid phases.
Mobility of Humic Substances in Groundwater
Authors: Buckau Gunnar 
Published: July 2005

Abstract

Humic substances are a relatively stable part of the global carbon inventory, originating mainly from decomposition of plant material but also marine organisms. In groundwater, the hydrophilic part of the total geochemical inventory is found. They originate from recharge or
in situ
generation by partial oxidation of hydrophobic sedimentary carbon sources, especially lignite sand. Because of their hydrophilic character and negative charge, they remain stable over long time periods and long transport times. This is especially true for the fulvic acid fraction with its smaller average molecular mass and higher oxygen functional group content than the complementary humic acid. Investigations in several types of aquifer systems show transport times up to 15,000 years and transport distances of more than 20 km. One exception is the salting out of the
in situ
generated fulvic acid inventory in brines in the vicinity of a salt dome. Variations in concentration, composition, and
14
C content of the aquatic humic substance inventory can give information over different recharge conditions, including climatic changes. Where no direct evidence can be given for the retention of aquatic humic substances, an ideal tracer behavior needs to be assumed. Consequently, they may play a key role in the transport of pollutants, including heavy metals and radionuclides.