Contaminated and Hazardous
Waste Site Management Glossary
B Backfill:
Material used temporarily during construction (e.g. of wells) or permanently during
mining to replace the material being removed. Background
Correction: A technique to compensate for variable background contribution to
the instrument signal in the determination of trace elements. Background
Level: The amount of a substance typically found in the air, water, or soil from
non-site related activities. Bacteria:
Unicellular microorganisms that exist either as free-living organisms or as parasites
and have a broad range of biochemical, and often pathogenic, properties. Bacteria
can be grouped by form into five general categories: cocci (spherical), bacilli
(rod-shaped), vibrio (curved rod-shaped), spirilla (spiral), and filamentous (thread-like). Baghouse:
A dust-collection chamber containing numerous permeable fabric filters through
which the exhaust gases pass. Finer particulates entrained in the exhaust gas
stream are collected in the filters for subsequent treatment/disposal. Bail
Test: A test carried out to determine in-situ hydraulic conductivity by instantaneously
removing a known water quantity from a well and measuring the resulting well recovery.
Used for single wells in low to moderate hydraulic conductivity formations. Also
called rising head test. Bailer:
A long, narrow tube with an open top and a check valve at the bottom. It is used
to remove water and/or cuttings from a borehole or well. Ball
Valve: A valve regulated by the position of a free-floating ball that moves in
response to fluid or mechanical pressure. Bar
Graph Spectrum: A plot of the mass-to-charge ratio (m/e) versus relative intensity
of the ion current. Base
Flow: The sustained low flow in a stream. Generally base flow is the inflow of
groundwater to the stream. Batch:
A group of samples prepared at the same time in the same location using the same
method. Bedding
Plane: A planar or nearly planar surface, within a mass of stratified rock layers,
that visibly separates each successive layer. Bedrock:
A general term referring to rock that underlies unconsolidated material. Bentonite:
A hydrous aluminium silicate clay mineral which is used to provide a seal between
well casing and the borehole. Also, it is sometimes added to drilling fluid to
increase its viscosity. Berm:
A sloped wall or embankment (typically constructed of earth, hay bales, or timber
framing) used to prevent inflow or outflow of material into/from an area. Bioaccumulate:
The process by which some contaminants or toxic chemicals gradually collect and
increase in concentration in living tissue, such as in plants, fish, or people,
as they breath contaminated air, drink contaminated water, or eat contaminated
food. Bias,
Biasing: A systematic difference between the true and measured value. Bioassay:
A method used to determine the toxicity of specific chemical contaminants. A number
of individuals of a sensitive species are placed in water containing specific
concentrations of the contaminant for a specified period of time. Bioaugmentation:
The introduction of cultured microorganisms into the subsurface environment
for the purpose of enhancing bioremediation of organic contaminants. Generally
the microorganisms are selected for their ability to degrade the organic compounds
present at the remediation site. The culture can be either an isolated genus
or a mix of more than one genera. Nutrients are usually also blended with
the aqueous solution containing the microbes to serve as a carrier and dispersant.
The liquid is introduced into the subsurface under natural conditions (gravity
fed) or injected under pressure. Bioavailability:
The availability of a compound for biodegradation, influenced by the compound's
location relative to microorganisms and its ability to dissolve in water. Biocide:
A substance capable of destroying (killing) living organisms. Biodegradability
(or biodegradation potential): The relative ease with which petroleum hydrocarbons
will degrade as the result of biological metabolism. Although virtually all petroleum
hydrocarbons are biodegradable, biodegradability is highly variable and dependent
somewhat on the type of hydrocarbon. In general, biodegradability increases with
increasing solubility; solubility is inversely proportional to molecular weight. Biodegradation:
A subset of biotransformation, it is the biologically mediated conversion of a
compound to more simple products. Biological
Activity: In the subsurface, usually the action of microorganisms, especially
bacteria. Biological
Treatment: The use of bacteria or other microbial organisms to break down toxic
organic materials into carbon dioxide and water. Biomass: the amount of living
matter in a given area or volume. Bioremediation:
A cleanup process using naturally occurring or specially cultivated microorganisms
to digest contaminants and break them down into non-hazardous components. Bit:
A cutting tool attached to the bottom of the drill stem. Its design varies according
to the type of drilling equipment used; based on the type of formation which is
to be drilled. Bladder
Pump: The pump consists of a flexible bladder within a rigid cylindrical frame.
The lower end of the bladder is connected to the intake port and the upper end
is connected to the sample line. A gas line leads from ground surface to the space
between the bladder and frame. After filling under hydrostatic pressure, application
of gas pressure causes the bladder to collapse, forcing the sample to ground surface
through the sample line. Blanks:
Samples that are the same as the samples of interest except in some respect whose
influence on the samples is being evaluated. For example, a trip blank is transported
just like actual samples, but it doesn't contain the chemicals to be analyzed.
It evaluates the possibility that a chemical could seep into the samples during
transportation to the laboratory. Boiling
Point: The temperature at which a component's vapor pressure equals atmospheric
pressure. Boiling point is a relative indicator of volatility and generally increases
with increasing molecular weight. Borehole:
A hole drilled or bored into the earth, and into which casing, screen, etc. may
be installed to construct a well. Borrow
Pit: An excavated area where soil, sand, or gravel has been dug up for use elsewhere. Boundary
Condition: A mathematical model must be defined within a physical domain; the
idealized flow or transport behaviour along the domain boundaries form the boundary
conditions of the model. Bouguer
Correction: The process of correcting gravity data for the mass of the rock between
a given station and its reference (base) station. Application of the Bouguer correction
to the data set, as well as corrections for latitude, topography, meter drift
and elevation, yields the Bouguer anomaly. Breakthrough
Curve: A plot of column effluent concentration over time. In the field, monitoring
a well produces a breakthrough curve for a column from a source to the well screen.
Breccia:
Fragments of rock, generally angular in a fine grained matrix, or a matrix of
cementing material. Breccias include tectonic brecccias, clastic brecccias and
volcanic breccias. Brecciated
Zone: A zone converted into a breccia. BTEX:
Abbreviation for benzene, toluene, ethylbenzene and xylenes which are the most
soluble compounds of gasoline. BTU
(British Thermal Unit): The quantity of heat required to raise the temperature
of one pound of water one degree Fahrenheit at 39?F; used as the standard for
comparison of heating values of fuels. Bubble
Radius: The maximum radial distance away from a biosparging well where the effects
of sparging are observable. Analogous to radius of influence of an air sparging
well. Buffer:
A substance (or mixture of substances) capable of neutralizing both acids and
bases when added to a solution, but without significantly changing its original
acidity or alkalinity. Bulk
Density: The amount of mass of a soil per unit volume of soil; where mass is measured
after all water has been extracted and total volume includes the volume of the
soil itself and the volume of air space (voids) between the soil grains. Bulk
Mass Density: The weight of a material divided by its volume (including the volume
of its pore spaces). Specifically, it refers to the weight per unit volume of
a soil mass that has been oven-dried to a constant weight at 105oC. Bulk
Modulus: A modulus of elasticity, relating change in volume to the hydrostatic
state of stress. It is the reciprocal of compressibility. Butterfly
Valve: A shut-off valve usually found in larger pipe sizes (4-inches or greater).
this type of valve can be used for non-critical flow control.
|