Contaminated and Hazardous
Waste Site Management
The process of matching a model simulation with observed data. Typically, one
or more model parameters are varied within reasonable limits until a suitable
match is obtained.
Blank: A volume of acidified deionized/distilled water.
Standards: A series of known standard solutions used by the analyst for calibration
of the instrument (i.e., preparation of the analytical curve).
A layer (or layers) of material, such as clay or a synthetic material, used to
prevent precipitation from penetrating and spreading contaminated materials. The
surface of the cap generally is mounded or sloped so water will drain off.
Forces: Interfacial forces between immiscible fluid phases, resulting in pressure
differences between the two phases.
Fringe: The zone immediately above the water table, in which water is drawn upward
by capillary action, and the pores are filled with water under pressure less than
Suction: The process whereby water rises above the water table into the void spaces
of a soil due to tension between the water and soil particles.
Zone: That portion of the groundwater flow system where the action of a pumping
well causes the groundwater to flow to or be captured by that well.
A finite, usually predetermined number of samples collected over a given time
period from a particular site. Case numbers are assigned by the Sample Management
Office. A Case consists of one or more Sample Delivery Groups.
A substance that causes cancer.
Adsorption: A treatment system in which contaminants are removed by forcing water
or air through tanks containing activated carbon, a specially treated material
that attracts and holds or retains contaminants.
Oxidizer: An off-gas post-treatment unit for control of organic compounds. Gas
enters the unit and passes over a support material coated with a catalyst (commonly
a noble metal such as platinum or rhodium) that promotes oxidation of the organics.
Catalytic oxidizers can also be very effective in controlling odors. High moisture
content and the presence of chlorine or sulfur compounds can adversely affect
the performance of the catalytic oxidizer.
A positively charged atom or radical.
Exchange Capacity (CEC): A measure of the availability of cations that can be
displaced from a solid surface and exchanged for other cations. For geologic materials,
the cation exchange capacity is the number of milliequivalents of cations that
can be exchanged per 100 grams of dry sample.
Process using centrifugal force to separate liquids of different specific gravities
or suspended colloidal particles, according to particle-size fractions.
Curve: a) A curve to show the relation between two changing values b) Refers to
one of a pair of conjugate curves in a surface, which has the property that the
directions of the tangents through any point of the curve are the characteristic
directions of the surface.
A determination of the approximate concentration range of compounds of interest
used to choose the appropriate analytical protocol.
Chargeability: The normalized (using the primary voltage) area under an induced
polarization (IP) decay curve, between two times, after the transmitted current
is stopped in a time domain survey. Usually expressed in millivolt-seconds per
Balance: A calculation in which the total number of positive charges in cations
are compared to the number of negative charges in anions. Since groundwater is
electrically neutral, the charges should be balanced.
Fixation: The use of chemicals to bind contaminants, thereby reducing the potential
for leaching or other movement.
and Microbiological Transformation: The conversion of a chemical to other chemicals
by either chemical or microbial processes.
Organisms that obtain energy from oxidation or reduction of inorganic or organic
Copper Arsenate: An insecticide/herbicide formed from salts of three toxic metals:
copper, chromium, and arsenic. This salt is used extensively as a wood preservative
in pressure-treating operations. It is highly toxic and water-soluble, making
it a relatively mobile contaminant in the environment.
Graph produced during a gas chromatograph analysis and showing the constituents
present and their relative concentration.
A large size amphitheatre shaped hollow which has been excavated by ice action
in mountainous regions.
Rock - (Detrital Rock): A sedimentary rock composed of fragments ofpre-existing
rocks or organic structures.
Actions taken to deal with a release or threatened release of hazardous substances
that could affect public health or the environment. The term is often used broadly
to describe various response actions or phases of remedial responses, such as
The process by which a landfill stops accepting wastes and is closed under Federal
and/or State guidelines to ensure the long-term protection of the public and the
of Storage: See Storage Coefficient.
of Variation (CV): The standard deviation as a percent of the arithmetic mean.
of Permeability: See Hydraulic Conductivity.
The tendency of similar parts of a body to hold together, due to intermolecular
Materials: Such as sand on a beach, lack this tendency.
Well: Constructed with horizontal lengths of screened collector pipe radiating
out from a central vertical well.
Fine-grained material in suspension. Specifically refers to a particle-size range
of less than 0.00024 mm.
Deposits: Weathered, unconsolidated materials transported and deposited by gravity.
The simultaneous metabolism of two compounds, in which the degradation of the
second compound (the secondary substrate) depends on the presence of the first
compound (the primary substrate). For example, in the process of degrading methane,
some bacteria can degrade hazardous chlorinated solvents that they would otherwise
be unable to attack.
A reaction in which a metal ion and one or more anionic ligands chemically bond.
Complexes often prevent the precipitation of metals.
Number: Comprised of a real and imaginary part.
Resistivity (CR): A geophysical effect, also the basis of the CR method, in which
polarization within the medium results in the voltage and applied current being
out of phase - that is, their ratio is complex. Also known as spectral IP. Induced
polarization (IP) is one form of complex resistivity.
The combining and homogenizing of samples (e.g., soils) prior to preforming an
analysis of the composite sample.
The relative volume reduction that geological material can undergo when a force
is applied or water is removed from the vicinity by pumping.
Algorithm: That part of the computer code containing the step-by-step solution
procedure for the mathematical equations of the hydrogeological model.
Code: The complete set of computer-language instructions which contain the input
data statements, computational algorithm, and output statements. Common computer
languages include BASIC, FORTRAN and PASCAL.
Gradient: The change in concentration from one point to another. This is the "force"
Level (low or medium): Characterization of soil samples or sample fractions as
low concentration or medium concentration is made on the basis of the laboratory's
preliminary screen, not on the basis of information entered on the Traffic Report
by the sampler. High concentration samples may be multi-phase, and are considered
to be those collected directly from drums, pits, ponds, lagoons or areas where
no dilution of waste is evident.
Model: Our idealization of a hydrogeological system on which we can base a mathematical
model. The conceptual model includes assumptions on the hydrostratigraphy, material
properties, dimensionality and governing processes.
The liquid that separates from a vapor during condensation.
The product of conductivity and thickness [Siemens].
Currents: Electrical current resulting from the movement of free charges (contrast
with displacement current).
A coefficient of proportionality describing the rate at which a fluid (e.g., water
or gas) can move through a permeable medium. Conductivity is a function of both
the intrinsic permeability of the porous medium and the kinematic viscosity of
the fluid which flows through it.
of Depression: The area around a discharging well where the hydraulic head (potentiometric
surface) in the aquifer has been lowered by pumping. In an unconfined aquifer,
the cone of depression is a cone-shaped depression in the water table where the
media has actually been dewatered.
Aquifer: A fully saturated aquifer overlain by a confining layer. The potentiometric
surface (hydraulic head) of the water in a confined aquifer is at an elevation
that is equal to or
higher than the base of the overlying confining layer.
Discharging wells in a confined aquifer
lower the potentiometric surface which
forms a cone of depression, but the saturated media is not
Bed: -A bed of impermeable material stratigraphically adjacent to one or more
aquifers. Confining bed is now used to replace terms such as "aquiclude",
"aquitard" and "aquifuge".
Layer: A geologic body of low hydraulic conductivity above or below one or more
aquifers. Also called an aquiclude.
The degree to which a fracture network is connected. When defined statistically,
fracture connectivity can be used to generate many different fracture network
realizations for use in groundwater flow and mass transport models.
A dissolved substance which moves as fast as water in the groundwater system,
and is not prone to attenuation beyond that occurring by diffusion and/or dispersion.
Naturally occurring geologic material that has been lithified and so has strength
and resists disintegration.
Test: A test in which a sample is confined laterally in a ring and compressed
between porous plates which are saturated with water.
An essential part or component of a system or group (e.g., an ingredient of a
chemical mixture). For instance, benzene is one constituent of gasoline.
The process of enclosing or containing hazardous substances in a structure, typically
in a pond or lagoon, to prevent the migration of contaminants into the environment.
Any physical, chemical, biological, or radiological substance in air, soil or
water that has an adverse effect.
Plume: Contaminants which encroach into a groundwater system are moved down gradient.
The area of the aquifer containing the degraded water which resulted from the
migration of a pollutant is called a contaminant plume.
The introduction into soil, air or water of a chemical, organic or radioactive
material or live organism that will adversely affect the medium's quality.
Concept: The model which considers the source(s), migration, fate and impact of
subsurface contaminants. Its precision should improve as site assessment progresses.
Plan: A document setting out an organized, planned, and coordinated course of
action to be followed in case of fire, explosion or other accidents that release
toxic chemicals, hazardous wastes or radioactive materials into the environment.
Calibration: Analytical standard run every 10 analytical samples or every 2 hours,
whichever is more frequent, to verify the calibration of the analytical system.
Liquid-Liquid Extraction: Synonymous with the terms continuous extraction, continuous
liquid extraction, and liquid extraction. This extraction technique involves boiling
the extraction solvent in a flask and condensing the solvent above the aqueous
sample. The condensed solvent drips through the sample, extracting compounds of
interest from the aqueous phase.
Map: A map with contour lines drawn at regular intervals to show surface configuration
(elevation), geophysical and geochemical data distributions.
Required Detection Limit (CRDL): Minimum level of detection acceptable under the
contract Statement of Work.
Limits: A range within which specified measurement results must fall to be compliant.
Control limits may be mandatory, requiring corrective action if exceeded, or advisory,
requiring that non-compliant data be flagged.
A continuous columnar sample of subsurface material extracted from a borehole.
Such a sample preserves the features of the sampled material.
Coefficient: A number (denoted "r") which indicates the degree of dependence
between two variables (e.g., concentration and absorbance). The more dependent
they are the closer the value of r is to 1.0. Determined on the basis of the least
Recovery: A legal process where PRPs can be required to pay back the Federal government
for money spent on cleanup actions.
Geophysical methods carried out between boreholes (see also Tomography).
Chemicals used in wood preserving operations and produced by distillation of tar,
including polycyclic aromatic hydrocarbons and polynuclear aromatic hydrocarbons.
Contaminating sediments, soils, and surface water. Creosotes may cause skin ulcerations
and cancer through prolonged exposure.
Noise: Geophysical noise caused by anthropogenic sources (cars, pumps, etc) as
well as wind, moving tree roots, etc..
Environment: The part of the environment which represents man-made features (e.g.
roads, buildings, canals, bridges) as opposed to natural features.
Density: A measure of current flow through a given (oriented) area [Amperes/ m2].
Channelling/Gathering: Channelling is a restriction of current flow due to an
insulating barrier or narrowing of a conductor. Current gathering is a concentration
of current in a locally, more conductive zone. The disproportionate influence
of lakes and swamps on VLF surveys is a well known example.
Fragments of soil or rock created by the drilling process (with or without free
water). Also called drill cuttings.
A type of separator for removal of larger particles from an exhaust gas stream.
Gas laden with particulates enters the cyclone and is directed to flow in a spiral
causing the entrained particulates to fall out and collect at the bottom. The
gas exits near the top of the cyclone.