Contaminated and Hazardous
Waste Site Management
The permanent or temporary layer of unfrozen ground above, within, or below permafrost.
The object at which a survey sighting is aimed.
Assistance Grant (TAG) Program: A grant program that provides funds for qualified
citizens' groups to hire independent technical advisors to help them understand
and comment on technical decisions relating to Superfund cleanup actions.
Bags: Gas-tight bags constructed of non-reactive material (Tedlar) for the collection
transport of gas/vapor samples.
A porous, permeable cup connected through a rigid tube to a pressure measuring
device (e.g. manometer, vacuum gage) which records in situ soil water matric potential
The condition whereby pore water rests at a pressure less than atmospheric.
In three dimensions, there are nine components of hydraulic conductivity or dispersion
and, in matrix form, they form a second-rank symmetric tensor. When the principal
directions of anisotropy coincide with the x, y, and z coordinate axes, the nine
components reduce to three. This is the usual approach for simplification in modelling.
Identified Compounds (TIC): Compounds detected in samples that are not target
compounds, internal standards, system monitoring compounds, or surrogates. Up
to 30 peaks (those greater than 10% of peak areas or heights of nearest internal
standards) are subjected to mass spectral library searches for tentative identification.
Electron Acceptor (TEA): A compound or molecule that accepts an electron (is reduced)
during metabolism (oxidation) of a carbon source. Under aerobic conditions molecular
oxygen is the terminal electron acceptor. Under anaerobic conditions a variety
of terminal electron acceptors may be used. In order of decreasing redox potential,
these TEAs include nitrate, manganic manganese, ferric iron, sulfate, and carbon
dioxide. Microorganisms preferentially utilize electron acceptors that provide
the maximum free energy during respiration. Of the common terminal electron acceptors
listed above, oxygen has the highest redox potential and provides the most free
energy during electron transfer.
Conductivity: Geophysical method in which EM methods measure directly the average
electrical conductivity of the ground. Operates at low induction number.
Pit: A shallow pit, made by a backhoe, to characterize the subsurface.
Desorber: Describes the primary treatment unit that heats petroleum-contaminated
materials and desorbs the organic materials into a purge gas or off-gas.
Desorption System: Refers to the thermal desorber and associated material handling,
treated soil handling, off-gas treatment, and residuals treatment systems.
Treatment: The use of heat to remove or destroy contaminants from soil.
A circuit component with a high negative temperature coefficient of resistance;
its resistance decreases as temperature increases.
A device consisting of two dissimilar conductors joined together at their ends.
Between the two junctions, a thermoelectric voltage is developed which is proportional
to the temperature difference between them. It can be used to measure the temperature
of one of the junctions when the other is held at a fixed, known temperature,
or to convert radiant energy into electric energy.
Man-made materials used for well casing; composed of different formulations of
plastics (e.g. PVC) which are softened by heating and hardened by cooling so that
they are easily moulded and extruded.
Consists of a generally unconsolidated, unsorted, unstratified heterogeneous mixture
of clay, silt, sand, gravel and boulders of different sizes and shapes. Till is
deposited directly by and underneath glacial ice without subsequent reworking
Unsorted, non-layered sediment carried by or deposited from
Critical Removals: Including emergencies lasting longer than 30 calendar days,
those releases requiring initiation of on-site activity within six months of the
lead agency's determination, based on the site evaluation, that a removal action
Domain: In geophysics refers to measurements analyzed according to their behaviour
in time. The usual alternative is frequency domain measurements.
Domain Reflectometry (TDR): A device which measures electrical characteristics
of wideband transmission systems. Commonly used to measure soil moisture content.
A method for analyzing solution composition by adding known quantities of a standardized
solution until a certain reaction (e.g. colour change, precipitation) is produced.
A method for determining the distribution of physical properties within the earth
by inverting the results of a large number of measurements made in three dimensions
(e.g. seismic, radar, resistivity, EM) between different source and receiver locations.
The relief and form of the land.
Tortuous: The relationship between the length of the flow channel followed by
water and the length of the porous media in which the flow is occurring. Groundwater
follows a tortuous path so, in this definition, tortuousity is always >1.
Dissolved Solids (TDS): Concentration of total dissolved solids (TDS) in groundwater
expressed in milligrams per litre (mg/L), is found by evaporating a measured volume
of filtered sample to dryness and weighing this dry solid residue.
Metals: Analyte elements which have been digested prior to analysis.
Petroleum Hydrocarbons (TPH): A measure of the mass or concentration of all the
petroleum constituents present in a given amount of air, soil, or water.
Recoverable Petroleum Hydrocarbons (TRPH): An EPA method (418.1) for measuring
petroleum hydrocarbons in samples of soil or water. Hydrocarbons are extracted
from the sample using a chlorofluorocarbon solvent (typically Freon-113) and quantified
by infrared spectrophotometry. The method specifies that the extract be passed
through silica gel to removethe non-petroleum fraction of the hydrocarbons.
(element): Any chemical (element) present in minute quantities in soil or water.
Report (TR): A sample identification form filled out by the sampler, which accompanies
the sample during shipment to the laboratory and which documents sample condition
and receipt by the laboratory. Also called Chain of Custody Report.
A device or element that converts an input signal into an output signal of a different
form. For example a pressure transducer converts pressure to an electric signal.
A chemical or biological change in the structure of a chemical. For example, toluene
may be transformed to toluic acid, or to H2O and CO2.
Occurring when the system is still changing with time; i.e., a steady state has
not been attained. Most groundwater flow systems are transient, not steady state.
The rate at which water of a certain density and viscosity is transmitted under
a unit hydraulic gradient through a unit width of an aquifer (or confining bed).
It is dependent on properties of the liquid and porous medium. Also known as the
Coefficient of Transmissibility.
In resistivity and induced polarization (IP) surveys, where current is injected
into the ground, it is a current waveform generator. In electromagnetic surveys,
which induce currents in the ground, it is typically a loop or grounded wire.
Process by which water vapour is released through the leaves of plants. This water
usually comes from the groundwater.
Time: The time it takes (for example) a contaminant to travel from the source
to a particular point downgradient.
Studies: Testing a treatment method on contaminated groundwater, soil, etc., to
determine whether and how well the method will work.
(TCE): A stable, colorless liquid with a low boiling point. TCE has many industrial
applications, including use as a solvent and as a metal degreasing agent. TCE
can be toxic to people when inhaled, ingested or through skin contact and can
damage vital organs, especially the liver.
A machine in which kinetic energy of a moving fluid is converted to mechanical
power by the impulse or reaction of the fluid with a series of buckets, blades,
or paddles arrayed about the circumference of a wheel or cylinder.
Wheel: A rotor designed to convert fluid energy into rotational energy. Hydraulic
turbines are used to extract energy from water as the water velocity increases
due to a change in head or kinetic energy at the expense of potential energy as
the water flows from a higher elevation to a lower elevation. The tangential component
of the fluid velocity contributes to the rotation of the rotor in a turbo-machine.
Time Period: The twelve (12) hour time period for GC/MS system instrument performance
check, standards calibration (initial or continuing calibration), and method blank
analysis begins at the moment of injection of the DBTPP or BFB analysis that the
laboratory submits as documentation of instrument performance. The time period
ends after 12 hours have elapsed according to the system clock. For pesticide/Arochlor
analyses performed by GC/EC, the twelve hour time period in the analytical sequence
begins at the moment of injection of the instrument blank that precedes sample
analyses, and ends after twelve hours have elapsed according to the system clock.