Misplaced Pages

#556443

102-561: The British Graham Land expedition ( BGLE ) was a geophysical and exploration expedition to Graham Land in Antarctica between 1934 and 1937. Under the leadership of John Rymill , the expedition spent two years in the Antarctic. The expedition determined that Graham Land was a peninsula. The expedition used a combination of traditional and modern practices in Antarctic exploration, using both dog teams and motor sledges as well as

204-516: A Superfund to remediate abandoned sites, or to litigate to force corporations to remediate their contaminated sites. Other countries have other mechanisms and commonly sites are rezoned to "higher" uses such as high density housing, to give the land a higher value so that after deducting cleanup costs there is still an incentive for a developer to purchase the land, clean it up, redevelop it and sell it on, often as apartments (home units). There are several tools for mapping these sites and which allow

306-458: A jail sentence for the polluter. Penalties must be significant as otherwise fines are treated as a normal expense of doing business. Compliance must be cheaper than to have continuous breaches. Assessment should be made of the risks of operations, transporting contaminated material, disposal of waste which may be contaminated including workers' clothes, and a formal emergency response plan should be developed. Every worker and visitor entering

408-477: A bronze ball from the mouth of a dragon into the mouth of a toad. By looking at which of eight toads had the ball, one could determine the direction of the earthquake. It was 1571 years before the first design for a seismoscope was published in Europe, by Jean de la Hautefeuille . It was never built. The 17th century had major milestones that marked the beginning of modern science. In 1600, William Gilbert release

510-450: A chemical free technology. Air microbubbles generated in water without adding any surfactant could be used to clean oil contaminated sediments. This technology holds promise over the use of chemicals (mainly surfactant) for traditional washing of oil contaminated sediments. In preparation for any significant remediation there should be extensive community consultation. The proponent should both present information to and seek information from

612-458: A compass in Europe was in 1190 AD. In circa 240 BC, Eratosthenes of Cyrene deduced that the Earth was round and measured the circumference of Earth with great precision. He developed a system of latitude and longitude . Perhaps the earliest contribution to seismology was the invention of a seismoscope by the prolific inventor Zhang Heng in 132 AD. This instrument was designed to drop

714-571: A concentration of 93% and bioaccumulation factor of 5.6, lead , mercury , zinc with a bioaccumulation factor of 3.6, and arsenic at a concentration of 22%. Black soldier fly larvae (BSFL) have also been used to monitor the degradation and reduction of anthropogenic oil contamination in the environment. Entomoremediation is considered viable as an accessible low-energy, low-carbon, and highly renewable method for environmental decontamination. Cleaning of oil contaminated sediments with self collapsing air microbubbles have been recently explored as

816-414: A faster rate than would larger particles. Most field applications of nanoremediation have used nano zero-valent iron (nZVI), which may be emulsified or mixed with another metal to enhance dispersion. That nanoparticles are highly reactive can mean that they rapidly clump together or react with soil particles or other material in the environment, limiting their dispersal to target contaminants. Some of

918-475: A magnetosphere. Early space probes mapped out the gross dimensions of the Earth's magnetic field, which extends about 10 Earth radii towards the Sun. The solar wind, a stream of charged particles, streams out and around the terrestrial magnetic field, and continues behind the magnetic tail , hundreds of Earth radii downstream. Inside the magnetosphere, there are relatively dense regions of solar wind particles called

1020-663: A million years or so, the polarity of the Earth's field reverses. These geomagnetic reversals , analyzed within a Geomagnetic Polarity Time Scale , contain 184 polarity intervals in the last 83 million years, with change in frequency over time, with the most recent brief complete reversal of the Laschamp event occurring 41,000 years ago during the last glacial period . Geologists observed geomagnetic reversal recorded in volcanic rocks, through magnetostratigraphy correlation (see natural remanent magnetization ) and their signature can be seen as parallel linear magnetic anomaly stripes on

1122-435: A publication titled De Magnete (1600) where he conducted series of experiments on both natural magnets (called 'loadstones ') and artificially magnetized iron. His experiments lead to observations involving a small compass needle ( versorium ) which replicated magnetic behaviours when subjected to a spherical magnet, along with it experiencing ' magnetic dips ' when it was pivoted on a horizontal axis. HIs findings led to

SECTION 10

#1732790260557

1224-417: A remediation project. The use of incremental health risk is based on carcinogenic and other (e.g., mutagenic , teratogenic ) effects and often involves value judgements about the acceptable projected rate of increase in cancer . In some jurisdictions this is 1 in 1,000,000 but in other jurisdictions the acceptable projected rate of increase is 1 in 100,000. A relatively small incremental health risk from

1326-459: A single project is not of much comfort if the area already has a relatively high health risk from other operations like incinerators or other emissions, or if other projects exist at the same time causing a greater cumulative risk or an unacceptably high total risk. An analogy often used by remediators is to compare the risk of the remediation on nearby residents to the risks of death through car accidents or tobacco smoking . Standards are set for

1428-515: A single-engine de Havilland Fox Moth aircraft for exploration. Transportation to the Antarctic was in an elderly three-masted sailing ship christened the Penola , which had an unreliable auxiliary engine. Additional supplies were brought on the ship Discovery II . The expedition was one of the last privately sponsored Antarctic missions, with only part of the cost covered by the UK government. Although

1530-476: Is a controversial step as: Often corporations which do voluntary testing of their sites are protected from the reports to environmental agencies becoming public under Freedom of Information Acts , however a "Freedom of Information" inquiry will often produce other documents that are not protected or will produce references to the reports. In the US there has been a mechanism for taxing polluting industries to form

1632-451: Is a gap of 12 hours and 25 minutes between every high tide and between every low tide. Gravitational forces make rocks press down on deeper rocks, increasing their density as the depth increases. Measurements of gravitational acceleration and gravitational potential at the Earth's surface and above it can be used to look for mineral deposits (see gravity anomaly and gravimetry ). The surface gravitational field provides information on

1734-414: Is a technology for soil remediation. During the process a desorber volatilizes the contaminants (e.g. oil, mercury or hydrocarbon) to separate them from especially soil or sludge. After that the contaminants can either be collected or destroyed in an offgas treatment system. Excavation processes can be as simple as hauling the contaminated soil to a regulated landfill , but can also involve aerating

1836-583: Is a variant of bioremediation in which insects decontaminate soils. Entomoremediation techniques engage microorganisms , collembolans , ants , flies , beetles , and termites . It is dependent on saprophytic insect larvae, resistant to adverse environmental conditions and able to bioaccumulate toxic heavy metal contaminants. Hermetia illucens (black soldier fly - BSF) is an important entomoremediation participant. H. illucens has been observed to reduce polluted substrate dry weight by 49%. H. illucens larvae have been observed to accumulate cadmium at

1938-538: Is a very complex substance and its unique properties are essential for life. Its physical properties shape the hydrosphere and are an essential part of the water cycle and climate . Its thermodynamic properties determine evaporation and the thermal gradient in the atmosphere . The many types of precipitation involve a complex mixture of processes such as coalescence , supercooling and supersaturation . Some precipitated water becomes groundwater , and groundwater flow includes phenomena such as percolation , while

2040-503: Is about 4.2 × 10 W , and it is a potential source of geothermal energy. Seismic waves are vibrations that travel through the Earth's interior or along its surface. The entire Earth can also oscillate in forms that are called normal modes or free oscillations of the Earth . Ground motions from waves or normal modes are measured using seismographs . If the waves come from a localized source such as an earthquake or explosion, measurements at more than one location can be used to locate

2142-449: Is also successful when utilized as the initial step in a multi-faceted remedial approach utilizing SEAR then In situ Oxidation, bioremediation enhancement or soil vapor extraction (SVE). Pump and treat involves pumping out contaminated groundwater with the use of a submersible or vacuum pump , and allowing the extracted groundwater to be purified by slowly proceeding through a series of vessels that contain materials designed to adsorb

SECTION 20

#1732790260557

2244-440: Is always a downward electric field near the surface that averages 120 volts per meter. Relative to the solid Earth, the ionization of the planet's atmosphere is a result of the galactic cosmic rays penetrating it, which leaves it with a net positive charge. A current of about 1800 amperes flows in the global circuit. It flows downward from the ionosphere over most of the Earth and back upwards through thunderstorms. The flow

2346-515: Is an effective remediation technology for soil. "Multi Phase Extraction" (MPE) is also an effective remediation technology when soil and groundwater are to be remediated coincidentally. SVE and MPE utilize different technologies to treat the off-gas volatile organic compounds (VOCs) generated after vacuum removal of air and vapors (and VOCs) from the subsurface and include granular activated carbon (most commonly used historically), thermal and/or catalytic oxidation and vapor condensation. Generally, carbon

2448-526: Is believed to be caused by high-energy electrons that get caught in the Van Allen radiation belt . Whistlers are produced by lightning strikes. Hiss may be generated by both. Electromagnetic waves may also be generated by earthquakes (see seismo-electromagnetics ). In the highly conductive liquid iron of the outer core, magnetic fields are generated by electric currents through electromagnetic induction. Alfvén waves are magnetohydrodynamic waves in

2550-551: Is concerned with the shape of the Earth, and by extension the mapping of features around and in the planet, geophysical measurements include high accuracy GPS measurements. These measurements are processed to increase their accuracy through differential GPS processing. Once the geophysical measurements have been processed and inverted, the interpreted results are plotted using GIS. Programs such as ArcGIS and Geosoft were built to meet these needs and include many geophysical functions that are built-in, such as upward continuation , and

2652-468: Is divided into the upper mantle , transition zone, lower mantle and D′′ layer. Between the crust and the mantle is the Mohorovičić discontinuity . The seismic model of the Earth does not by itself determine the composition of the layers. For a complete model of the Earth, mineral physics is needed to interpret seismic velocities in terms of composition. The mineral properties are temperature-dependent, so

2754-641: Is generally subject to an array of regulatory requirements, and may also be based on assessments of human health and ecological risks where no legislative standards exist, or where standards are advisory. In the United States , the most comprehensive set of Preliminary Remediation Goals (PRGs) is from the Environmental Protection Agency (EPA) Regional Screening Levels (RSLs). A set of standards used in Europe exists and

2856-512: Is likely to come in contact is of particular importance for barriers constructed from fluids which are supposed to set in-situ. EPA emphasizes this compatibility in its guidance documents, noting that thorough characterization of the waste, leachate, barrier material chemistry, site geochemistry, and compatibility testing of the barrier material with the likely disposal site chemical environment are all required." These guidelines are for all materials - experimental and traditional. Thermal desorption

2958-459: Is liquid, and the motion of this highly conductive fluid generates the Earth's field. Earth's inner core , however, is solid because of the enormous pressure. Reconstruction of seismic reflections in the deep interior indicates some major discontinuities in seismic velocities that demarcate the major zones of the Earth: inner core , outer core , mantle, lithosphere and crust . The mantle itself

3060-410: Is mainly composed of silicates , and the boundaries between layers of the mantle are consistent with phase transitions. The mantle acts as a solid for seismic waves, but under high pressures and temperatures, it deforms so that over millions of years it acts like a liquid. This makes plate tectonics possible. If a planet's magnetic field is strong enough, its interaction with the solar wind forms

3162-466: Is manifested by lightning below the clouds and sprites above. A variety of electric methods are used in geophysical survey. Some measure spontaneous potential , a potential that arises in the ground because of human-made or natural disturbances. Telluric currents flow in Earth and the oceans. They have two causes: electromagnetic induction by the time-varying, external-origin geomagnetic field and motion of conducting bodies (such as seawater) across

British Graham Land expedition - Misplaced Pages Continue

3264-578: Is often called the Dutch standards . The European Union (EU) is rapidly moving towards Europe-wide standards, although most of the industrialised nations in Europe have their own standards at present. In Canada , most standards for remediation are set by the provinces individually, but the Canadian Council of Ministers of the Environment provides guidance at a federal level in the form of

3366-414: Is the impact on local traffic, schools, playing fields, and other public facilities due to the increased population. Dioxins from Union Carbide used in the production of now-banned pesticide 2,4,5-Trichlorophenoxyacetic acid and defoliant Agent Orange polluted Homebush Bay . Remediation was completed in 2010, but fishing will continue to be banned for decades. An EU contract for immobilization of

3468-404: Is the possibility of decreasing anaerobic contaminant destruction natural attenuation where existing conditions enhance anaerobic bacteria which normally live in the soil prefer a reducing environment . In general, aerobic activity is much faster than anaerobic and overall destruction rates are typically greater when aerobic activity can be successfully promoted. The injection of gases into

3570-455: Is then captured and pumped out by extraction wells for further treatment at the surface. Then the water after treatment is discharged into surface water or re-injected into groundwater. In geologic formations that allow delivery of hydrocarbon mitigation agents or specialty surfactants, this approach provides a cost-effective and permanent solution to sites that have been previously unsuccessful utilizing other remedial approaches. This technology

3672-467: Is used for low (below 500 ppmV) VOC concentration vapor streams, oxidation is used for moderate (up to 4,000 ppmV) VOC concentration streams, and vapor condensation is used for high (over 4,000 ppmV) VOC concentration vapor streams. Below is a brief summary of each technology. Using nano-sized reactive agents to degrade or immobilize contaminants is termed nanoremediation . In soil or groundwater nanoremediation, nanoparticles are brought into contact with

3774-484: The Adams–Williamson equation . The conclusion is that pressure alone cannot account for the increase in density. Instead, we know that the Earth's core is composed of an alloy of iron and other minerals. Reconstructions of seismic waves in the deep interior of the Earth show that there are no S-waves in the outer core. This indicates that the outer core is liquid, because liquids cannot support shear. The outer core

3876-659: The Canadian Environmental Quality Guidelines and the Canada-Wide Standards|Canada-Wide Standard for Petroleum Hydrocarbons in Soil . Once a site is suspected of being contaminated there is a need to assess the contamination. Often the assessment begins with preparation of a Phase I Environmental Site Assessment . The historical use of the site and the materials used and produced on site will guide

3978-539: The International Union of Geodesy and Geophysics encompass both. Absolute positions are most frequently determined using the global positioning system (GPS). A three-dimensional position is calculated using messages from four or more visible satellites and referred to the 1980 Geodetic Reference System . An alternative, optical astronomy , combines astronomical coordinates and the local gravity vector to get geodetic coordinates. This method only provides

4080-405: The conductivity of water makes electrical and electromagnetic methods useful for tracking groundwater flow. Physical properties of water such as salinity have a large effect on its motion in the oceans. The many phases of ice form the cryosphere and come in forms like ice sheets , glaciers , sea ice , freshwater ice, snow, and frozen ground (or permafrost ). Contrary to popular belief,

4182-443: The elastic properties of minerals; their high-pressure phase diagrams , melting points and equations of state at high pressure; and the rheological properties of rocks, or their ability to flow. Deformation of rocks by creep make flow possible, although over short times the rocks are brittle. The viscosity of rocks is affected by temperature and pressure, and in turn, determines the rates at which tectonic plates move. Water

British Graham Land expedition - Misplaced Pages Continue

4284-442: The geotherm must also be determined. This requires physical theory for thermal conduction and convection and the heat contribution of radioactive elements . The main model for the radial structure of the interior of the Earth is the preliminary reference Earth model (PREM). Some parts of this model have been updated by recent findings in mineral physics (see post-perovskite ) and supplemented by seismic tomography . The mantle

4386-465: The magnetosphere or the Earth's core. In the core, they probably have little observable effect on the Earth's magnetic field, but slower waves such as magnetic Rossby waves may be one source of geomagnetic secular variation . Electromagnetic methods that are used for geophysical survey include transient electromagnetics , magnetotellurics , surface nuclear magnetic resonance and electromagnetic seabed logging. The Earth's magnetic field protects

4488-490: The precession of the equinox (the orbit of whole star patterns along an ecliptic axis . Newton's theory of gravity had gained so much success, that it resulted in changing the main objective of physics in that era to unravel natures fundamental forces, and their characterizations in laws. The first seismometer , an instrument capable of keeping a continuous record of seismic activity, was built by James Forbes in 1844. Environmental remediation Remedial action

4590-465: The EPA; however, the EPA traditionally has been more cautious about negative externalities that may or may not arise from the introduction of these species. One of their concerns is that the toxic chemicals would lead to the microbe's gene degradation, which would then be passed on to other harmful bacteria, creating more issues, if the pathogens evolve the ability to feed off of pollutants. Entomoremediation

4692-522: The Earth and its surroundings. Geophysicists also investigate the physical processes and properties of the Earth, its fluid layers, and magnetic field along with the near-Earth environment in the Solar System , which includes other planetary bodies. The gravitational pull of the Moon and Sun gives rise to two high tides and two low tides every lunar day, or every 24 hours and 50 minutes. Therefore, there

4794-447: The Earth from the deadly solar wind and has long been used for navigation. It originates in the fluid motions of the outer core. The magnetic field in the upper atmosphere gives rise to the auroras . The Earth's field is roughly like a tilted dipole , but it changes over time (a phenomenon called geomagnetic secular variation). Mostly the geomagnetic pole stays near the geographic pole , but at random intervals averaging 440,000 to

4896-599: The Earth rotates, as the Earth orbits the Sun, and as the moon orbits the Earth. Geophysical measurements are often recorded as time-series with GPS location. Signal processing involves the correction of time-series data for unwanted noise or errors introduced by the measurement platform, such as aircraft vibrations in gravity data. It also involves the reduction of sources of noise, such as diurnal corrections in magnetic data. In seismic data, electromagnetic data, and gravity data, processing continues after error corrections to include computational geophysics which result in

4998-461: The Earth's crust to the rebound due to the release of the pressure ), geological features such as mountains or ocean trenches , tectonic plate dynamics, and natural disasters can further distort the planet's shape. Evidence from seismology , heat flow at the surface, and mineral physics is combined with the Earth's mass and moment of inertia to infer models of the Earth's interior – its composition, density, temperature, pressure. For example,

5100-483: The Earth's magnetic field and earthquakes – have been investigated since the ancient era . The magnetic compass existed in China back as far as the fourth century BC. It was used as much for feng shui as for navigation on land. It was not until good steel needles could be forged that compasses were used for navigation at sea; before that, they could not retain their magnetism long enough to be useful. The first mention of

5202-454: The Earth's mean specific gravity ( 5.515 ) is far higher than the typical specific gravity of rocks at the surface ( 2.7–3.3 ), implying that the deeper material is denser. This is also implied by its low moment of inertia ( 0.33 M R , compared to 0.4 M R for a sphere of constant density). However, some of the density increase is compression under the enormous pressures inside the Earth. The effect of pressure can be calculated using

SECTION 50

#1732790260557

5304-472: The Earth's permanent magnetic field. The distribution of telluric current density can be used to detect variations in electrical resistivity of underground structures. Geophysicists can also provide the electric current themselves (see induced polarization and electrical resistivity tomography ). Electromagnetic waves occur in the ionosphere and magnetosphere as well as in Earth's outer core . Dawn chorus

5406-621: The Earth's shape, density and gravity field, as well as the components of the water cycle. In the 20th century, geophysical methods were developed for remote exploration of the solid Earth and the ocean, and geophysics played an essential role in the development of the theory of plate tectonics. Geophysics is applied to societal needs, such as mineral resources , mitigation of natural hazards and environmental protection . In exploration geophysics , geophysical survey data are used to analyze potential petroleum reservoirs and mineral deposits, locate groundwater, find archaeological relics, determine

5508-529: The USA. Contaminants can be removed from a site or controlled. One option for control are barrier walls, which can be temporary to prevent contamination during treatment and removal, or more permanent. Techniques to construct barrier walls are deep soil mixing , jet grouting , low pressure grouting with cement and chemicals, freezing and slurry walls. Barrier walls must be constructed of impermeable materials and resistant to deterioration from contact with waste, for

5610-624: The Van Allen radiation belts. Geophysical measurements are generally at a particular time and place. Accurate measurements of position, along with earth deformation and gravity, are the province of geodesy . While geodesy and geophysics are separate fields, the two are so closely connected that many scientific organizations such as the American Geophysical Union , the Canadian Geophysical Union and

5712-436: The aim of investigating different energy, mineral and water resources. This is done through the uses of various remote sensing platforms such as; satellites , aircraft , boats , drones , borehole sensing equipment and seismic receivers . These equipment are often used in conjunction with different geophysical methods such as magnetic , gravimetry , electromagnetic , radiometric , barometry methods in order to gather

5814-630: The assessment strategy and type of sampling and chemical analysis to be done. Often nearby sites owned by the same company or which are nearby and have been reclaimed, levelled or filled are also contaminated even where the current land use seems innocuous. For example, a car park may have been levelled by using contaminated waste in the fill . Also important is to consider off site contamination of nearby sites often through decades of emissions to soil , groundwater , and air. Ceiling dust, topsoil , surface and groundwater of nearby properties should also be tested, both before and after any remediation. This

5916-425: The calculation of the measurement derivative such as the first-vertical derivative. Many geophysics companies have designed in-house geophysics programs that pre-date ArcGIS and GeoSoft in order to meet the visualization requirements of a geophysical dataset. Exploration geophysics is a branch of applied geophysics that involves the development and utilization of different seismic or electromagnetic methods which

6018-484: The changes in acceleration experienced by spacecraft as they orbit has allowed fine details of the gravity fields of the planets to be mapped. For example, in the 1970s, the gravity field disturbances above lunar maria were measured through lunar orbiters , which led to the discovery of concentrations of mass, mascons , beneath the Imbrium , Serenitatis , Crisium , Nectaris and Humorum basins. Since geophysics

6120-437: The community should be engaged (at proponent expense if a fee is required). Minutes of meetings including questions asked and the answers to them and copies of presentations by the proponent should be available both on the internet and at a local library (even a school library) or community centre. Incremental health risk is the increased risk that a receptor (normally a human being living nearby) will face from (the lack of)

6222-402: The community. The proponent needs to learn about "sensitive" (future) uses like childcare, schools, hospitals, and playgrounds as well as community concerns and interests information. Consultation should be open, on a group basis so that each member of the community is informed about issues they may not have individually thought about. An independent chairperson acceptable to both the proponent and

SECTION 60

#1732790260557

6324-509: The compounds used which vary in viscosity, gel time and density: "The selection of subsurface barriers for any given site which needs remediation, and the selection of a particular barrier technology must be done, however, by means of the Superfund Process, with special emphasis on the remedial investigation and feasibility study portions. The chemical compatibility of the material with the wastes, leachates and geology with which it

6426-461: The concentration and distribution of radioisotopes near the Earth's surface, which is useful for mapping lithology and alteration. Fluid motions occur in the magnetosphere, atmosphere , ocean, mantle and core. Even the mantle, though it has an enormous viscosity , flows like a fluid over long time intervals. This flow is reflected in phenomena such as isostasy , post-glacial rebound and mantle plumes . The mantle flow drives plate tectonics and

6528-627: The contaminant through either in situ injection or a pump-and-treat process. The nanomaterials then degrade organic contaminants through redox reactions or adsorb to and immobilize metals such as lead or arsenic . In commercial settings, this technology has been dominantly applied to groundwater remediation , with research into wastewater treatment . Research is also investigating how nanoparticles may be applied to cleanup of soil and gases. Nanomaterials are highly reactive because of their high surface area per unit mass, and due to this reactivity nanomaterials may react with target contaminants at

6630-495: The contaminants from the groundwater. For petroleum-contaminated sites this material is usually activated carbon in granular form. Chemical reagents such as flocculants followed by sand filters may also be used to decrease the contamination of groundwater. Air stripping is a method that can be effective for volatile pollutants such as BTEX compounds found in gasoline. For most biodegradable materials like BTEX , MTBE and most hydrocarbons, bioreactors can be used to clean

6732-442: The contaminated water to non-detectable levels. With fluidized bed bioreactors it is possible to achieve very low discharge concentrations which will meet or exceed discharge requirements for most pollutants. Depending on geology and soil type, pump and treat may be a good method to quickly reduce high concentrations of pollutants. It is more difficult to reach sufficiently low concentrations to satisfy remediation standards, due to

6834-579: The data. The remote sensing platforms used in exploration geophysics are not perfect and need adjustments done on them in order to accurately account for the effects that the platform itself may have on the collected data. For example, when gathering aeromagnetic data (aircraft gathered magnetic data) using a conventional fixed-wing aircraft- the platform has to be adjusted to account for the electromagnetic currents that it may generate as it passes through Earth's magnetic field . There are also corrections related to changes in measured potential field intensity as

6936-399: The deduction that compasses point north due to the Earth itself being a giant magnet. In 1687 Isaac Newton published his work titled Principia which was pivotal in the development of modern scientific fields such as astronomy and physics . In it, Newton both laid the foundations for classical mechanics and gravitation , as well as explained different geophysical phenomena such as

7038-589: The degradation of the target pollutants. Broad categories of bioremediation include biostimulation , bioaugmentation , and natural recovery ( natural attenuation ). Bioremediation is either done on the contaminated site (in situ) or after the removal of contaminated soils at another more controlled site (ex situ). In the past, it has been difficult to turn to bioremediation as an implemented policy solution, as lack of adequate production of remediating microbes led to little options for implementation. Those that manufacture microbes for bioremediation must be approved by

7140-523: The dissolved oxygen content of the groundwater to support microbial degradation of the compound (especially petroleum) by direct injection of oxygen into the subsurface, or the direct injection of a slurry that slowly releases oxygen over time (typically magnesium peroxide or calcium oxy-hydroxide). Solidification and stabilization work has a reasonably good track record but also a set of serious deficiencies related to durability of solutions and potential long-term effects. In addition CO 2 emissions due to

7242-554: The distance between the two satellites using GPS and a microwave ranging system. Gravity variations detected by GRACE include those caused by changes in ocean currents; runoff and ground water depletion; melting ice sheets and glaciers. Satellites in space have made it possible to collect data from not only the visible light region, but in other areas of the electromagnetic spectrum . The planets can be characterized by their force fields: gravity and their magnetic fields , which are studied through geophysics and space physics. Measuring

7344-542: The dynamics of tectonic plates . The geopotential surface called the geoid is one definition of the shape of the Earth. The geoid would be the global mean sea level if the oceans were in equilibrium and could be extended through the continents (such as with very narrow canals). The Earth is cooling, and the resulting heat flow generates the Earth's magnetic field through the geodynamo and plate tectonics through mantle convection . The main sources of heat are: primordial heat due to Earth's cooling and radioactivity in

7446-478: The earth is not entirely spherical but instead generally exhibits an ellipsoid shape- which is a result of the centrifugal forces the planet generates due to its constant motion. These forces cause the planets diameter to bulge towards the Equator and results in the ellipsoid shape . Earth's shape is constantly changing, and different factors including glacial isostatic rebound (large ice sheets melting causing

7548-561: The earth up to several kilometers deep and are used to increase our understanding of the geology as well as to explore for oil and gas. Changes in the travel direction, called refraction , can be used to infer the deep structure of the Earth . Earthquakes pose a risk to humans . Understanding their mechanisms, which depend on the type of earthquake (e.g., intraplate or deep focus ), can lead to better estimates of earthquake risk and improvements in earthquake engineering . Although we mainly notice electricity during thunderstorms , there

7650-450: The emission is emanating from an area zoned industrial does not mean that in a nearby residential area there should be permitted any exceedances of the appropriate residential standards. Monitoring for compliance against each standards is critical to ensure that exceedances are detected and reported both to authorities and the local community. Enforcement is necessary to ensure that continued or significant breaches result in fines or even

7752-546: The equilibrium of absorption / desorption processes in the soil. However, pump and treat is typically not the best form of remediation. It is expensive to treat the groundwater, and typically is a very slow process to clean up a release with pump and treat. It is best suited to control the hydraulic gradient and keep a release from spreading further. Better options of in-situ treatment often include air sparge/soil vapor extraction (AS/SVE) or dual phase extraction/multiphase extraction (DPE/MPE). Other methods include trying to increase

7854-518: The excavated material in the case of volatile organic compounds (VOCs) . Recent advancements in bioaugmentation and biostimulation of the excavated material have also proven to be able to remediate semi-volatile organic compounds (SVOCs) onsite. If the contamination affects a river or bay bottom, then dredging of bay mud or other silty clays containing contaminants (including sewage sludge with harmful microorganisms ) may be conducted. Recently, ExSitu Chemical oxidation has also been utilized in

7956-607: The expedition had a very small budget, it was successful in its scientific objectives. Air survey photography and mapping was carried out for 1000 miles (1600 km) of the Graham Land coast. All sixteen members of the landing party received the Polar Medal . The participants of the BGLE included: Geophysical Geophysics ( / ˌ dʒ iː oʊ ˈ f ɪ z ɪ k s / ) is a subject of natural science concerned with

8058-487: The final interpretation of the geophysical data into a geological interpretation of the geophysical measurements Geophysics emerged as a separate discipline only in the 19th century, from the intersection of physical geography , geology , astronomy , meteorology, and physics. The first known use of the word geophysics was in German ("Geophysik") by Julius Fröbel in 1834. However, many geophysical phenomena – such as

8160-554: The flow in the Earth's core drives the geodynamo. Geophysical fluid dynamics is a primary tool in physical oceanography and meteorology . The rotation of the Earth has profound effects on the Earth's fluid dynamics, often due to the Coriolis effect . In the atmosphere, it gives rise to large-scale patterns like Rossby waves and determines the basic circulation patterns of storms. In the ocean, they drive large-scale circulation patterns as well as Kelvin waves and Ekman spirals at

8262-505: The generation of magmas , volcanism and rock formation. However, modern geophysics organizations and pure scientists use a broader definition that includes the water cycle including snow and ice; fluid dynamics of the oceans and the atmosphere ; electricity and magnetism in the ionosphere and magnetosphere and solar-terrestrial physics ; and analogous problems associated with the Moon and other planets. Although geophysics

8364-594: The geodynamo and plate tectonics. The main heat-producing isotopes are potassium-40 , uranium-238 , uranium-235, and thorium-232 . Radioactive elements are used for radiometric dating , the primary method for establishing an absolute time scale in geochronology . Unstable isotopes decay at predictable rates, and the decay rates of different isotopes cover several orders of magnitude, so radioactive decay can be used to accurately date both recent events and events in past geologic eras . Radiometric mapping using ground and airborne gamma spectrometry can be used to map

8466-573: The groundwater may also cause contamination to spread faster than normal depending on the hydrogeology of the site. In these cases, injections downgradient of groundwater flow may provide adequate microbial destruction of contaminants prior to exposure to surface waters or drinking water supply wells. Migration of metal contaminants must also be considered whenever modifying subsurface oxidation-reduction potential. Certain metals are more soluble in oxidizing environments while others are more mobile in reducing environments. Soil vapor extraction (SVE)

8568-494: The important challenges currently limiting nanoremediation technologies include identifying coatings or other formulations that increase dispersal of the nanoparticle agents to better reach target contaminants while limiting any potential toxicity to bioremediation agents, wildlife, or people. Bioremediation is a process that treats a polluted area either by altering environmental conditions to stimulate growth of microorganisms or through natural microorganism activity, resulting in

8670-421: The levels of dust, noise, odour, emissions to air and groundwater, and discharge to sewers or waterways of all chemicals of concern or chemicals likely to be produced during the remediation by processing of the contaminants. These are compared against both natural background levels in the area and standards for areas zoned as nearby areas are zoned and against standards used in other recent remediations. Just because

8772-468: The lifespan of the barrier wall. It wasn't until the use of newer polymer and chemical grouts in the 1950s and 1960s that Federal agencies of the US government recognized the need to establish a minimum project life of 50 years in real world applications. The Department of Energy is one US government agency that sponsors research to formulate, test and determine use applications for innovative polymer grouts used in waste containment barriers. Portland cement

8874-415: The ocean surface. In the Earth's core, the circulation of the molten iron is structured by Taylor columns . Waves and other phenomena in the magnetosphere can be modeled using magnetohydrodynamics . The physical properties of minerals must be understood to infer the composition of the Earth's interior from seismology , the geothermal gradient and other sources of information. Mineral physicists study

8976-612: The physical processes and physical properties of the Earth and its surrounding space environment, and the use of quantitative methods for their analysis. Geophysicists, who usually study geophysics, physics , or one of the Earth sciences at the graduate level, complete investigations across a wide range of scientific disciplines. The term geophysics classically refers to solid earth applications: Earth's shape ; its gravitational , magnetic fields , and electromagnetic fields  ; its internal structure and composition ; its dynamics and their surface expression in plate tectonics ,

9078-407: The planets upper crust. There is also some contributions from phase transitions . Heat is mostly carried to the surface by thermal convection , although there are two thermal boundary layers – the core–mantle boundary and the lithosphere – in which heat is transported by conduction . Some heat is carried up from the bottom of the mantle by mantle plumes . The heat flow at the Earth's surface

9180-400: The position in two coordinates and is more difficult to use than GPS. However, it is useful for measuring motions of the Earth such as nutation and Chandler wobble . Relative positions of two or more points can be determined using very-long-baseline interferometry . Gravity measurements became part of geodesy because they were needed to related measurements at the surface of the Earth to

9282-605: The reference coordinate system. Gravity measurements on land can be made using gravimeters deployed either on the surface or in helicopter flyovers. Since the 1960s, the Earth's gravity field has been measured by analyzing the motion of satellites. Sea level can also be measured by satellites using radar altimetry , contributing to a more accurate geoid . In 2002, NASA launched the Gravity Recovery and Climate Experiment (GRACE), wherein two twin satellites map variations in Earth's gravity field by making measurements of

9384-465: The remediation of contaminated soil. This process involves the excavation of the contaminated area into large bermed areas where they are treated using chemical oxidation methods. This is used in removing non-aqueous phase liquids (NAPLs) from aquifer. This is done by pumping surfactant solution into contaminated aquifer using injection wells which are passed through contaminated zones to the extraction wells. The Surfactant solution containing contaminants

9486-435: The seafloor. These stripes provide quantitative information on seafloor spreading , a part of plate tectonics. They are the basis of magnetostratigraphy , which correlates magnetic reversals with other stratigraphies to construct geologic time scales. In addition, the magnetization in rocks can be used to measure the motion of continents. Radioactive decay accounts for about 80% of the Earth's internal heat , powering

9588-405: The site should have a safety induction personalised to their involvement with the site. Local communities and government often resist the rezoning because of the adverse effects of the remediation and new development on the local amenities. The main impacts during remediation are noise, dust, odour, and incremental health risk. Then there is the noise, dust, and traffic of developments. Then, there

9690-404: The source. The locations of earthquakes provide information on plate tectonics and mantle convection. Recording of seismic waves from controlled sources provides information on the region that the waves travel through. If the density or composition of the rock changes, waves are reflected. Reflections recorded using Reflection Seismology can provide a wealth of information on the structure of

9792-728: The surface as well as extraction of contaminated groundwater and treatment at the surface. In-situ methods seek to treat the contamination without removing the soils or groundwater. Various technologies have been developed for remediation of oil-contaminated soil/sediments. Traditional remediation approaches consist of soil excavation and disposal to landfill and groundwater "pump and treat". In-situ technologies include but are not limited to: solidification and stabilization , soil vapor extraction , permeable reactive barriers, monitored natural attenuation, bioremediation - phytoremediation , chemical oxidation, steam-enhanced extraction and in situ thermal desorption and have been used extensively in

9894-424: The thickness of glaciers and soils, and assess sites for environmental remediation . Geophysics is a highly interdisciplinary subject, and geophysicists contribute to every area of the Earth sciences , while some geophysicists conduct research in the planetary sciences . To provide a more clear idea on what constitutes geophysics, this section describes phenomena that are studied in physics and how they relate to

9996-459: The use of cement are also becoming a major obstacle to its widespread use in solidification/stabilization projects. Stabilization/solidification (S/S) is a remediation and treatment technology that relies on the reaction between a binder and soil to stop/prevent or reduce the mobility of contaminants. Conventional S/S is an established remediation technology for contaminated soils and treatment technology for hazardous wastes in many countries in

10098-910: The user to view additional information. One such tool is TOXMAP , a Geographic Information System (GIS) from the Division of Specialized Information Services of the United States National Library of Medicine (NLM) that uses maps of the United States to help users visually explore data from the United States Environmental Protection Agency 's (EPA) Superfund and Toxics Release Inventory programs. Remediation technologies are many and varied but can generally be categorized into ex-situ and in-situ methods. Ex-situ methods involve excavation of affected soils and subsequent treatment at

10200-616: The world. However, the uptake of S/S technologies has been relatively modest, and a number of barriers have been identified including: New in situ oxidation technologies have become popular for remediation of a wide range of soil and groundwater contaminants. Remediation by chemical oxidation involves the injection of strong oxidants such as hydrogen peroxide , ozone gas, potassium permanganate or persulfates. Oxygen gas or ambient air can also be injected to promote growth of aerobic bacteria which accelerate natural attenuation of organic contaminants. One disadvantage of this approach

10302-444: Was only recognized as a separate discipline in the 19th century, its origins date back to ancient times. The first magnetic compasses were made from lodestones , while more modern magnetic compasses played an important role in the history of navigation. The first seismic instrument was built in 132 AD. Isaac Newton applied his theory of mechanics to the tides and the precession of the equinox ; and instruments were developed to measure

10404-399: Was used in the past, however cracking and poor performance under wet-dry conditions at arid sites need improved materials to remedy. Sites that need remediation have variable humidity, moisture and soil conditions. Field implementation remains challenging: different environmental and site conditions require different materials and the placement technologies are specific to the characteristics of

#556443