Remediation and Environmental Definitions
This is a glossary with definitions of terms related to remediation and environmental pollutants.
A
ASBESTOS - (1)
A common form of magnesium silicate which was used in various construction
products due to it's stability and resistance to fire. Asbestos exposure
by inhaling loose asbestos fibers is associated with various forms of
lung disease. (2) The name given to certain inorganic minerals when
they occur in fibrous form. Though fire-resistant, its extremely fine
fibers are easily inhaled, and exposure to them over a period of years
has been linked to cancers of the lung or lung-cavity lining and to
asbestosis, a severe lung impairment.
ARSENIC: 1. As, atomic number 33 -- (a very poisonous
metallic element that has three allotropic forms; arsenic and arsenic
compounds are used as herbicides and insecticides and various alloys;
found in arsenopyrite and orpiment and realgar)
2. arsenic trioxide, arsenous anhydride, arsenous oxide -- (a white
powdered poisonous trioxide of arsenic; used in manufacturing glass
and as a pesticide and weed killer)
B
BENTONITE: Either
of two clays that are formed by the decomposition of volcanic ash, and
that are very absorptive and capable of expanding to several times their
normal volume.
BIOREMEDIATION: The process by which living
organisms act to degrade or transform hazardous organic contaminants.
BIOSLURPING: Designed to withdraw groundwater,
free product, and soil gas in the same process stream using a single pump.
Groundwater is separated from the free product and is treated and discharged.
BIOVENTING: The process of supplying oxygen in situ to oxygen deprived
soil microbes by forcing air through unsaturated contaminated soil at
low flow rates. This stimulates biodegradation and minimizes stripping
volatiles into the atmosphere. Frequently used to remediate soil under
structures since it is relatively non-invasive.
BROWNFIELD: An abandoned, idled, or under-used industrial or commercial
facility where expansion or redevelopment is complicated by a real or
perceived environmental contamination.
C
CHLORINATE: (v.
t.) To treat, or cause to combine, with chlorine.
CHROMIUM: chromium, Cr, atomic number 24 -- a hard
brittle blue-white multivalent metallic element; resistant to corrosion
and tarnishing
CREOSOTE: An antifungal wood preservative used
frequently to treat telephone poles and railroad ties. Creosote consists
of coal tar distillation products, including PHENOLS and PAHs.
D
DECHLORINATION: This is a chemical reaction
that removes or replaces chlorine atoms contained in hazardous compounds,
rendering them less hazardous.
DIOXIN: Any of a family of compounds known chemically
as dibenzo-p-dioxins. Concern about them arises from their potential toxicity
as contaminants in commercial products. Tests on laboratory animals indicate
that it is one of the more toxic anthropogenic (man-made) compounds.
E
EX SITU: Out of the original position (Excavated).
EROSION CONTROL: Methods to control land surface features to prevent erosion by surface water or precipitation runoff, the act of reducing or eliminating on-going erosion caused by natural or man-made processes and/or the practice of preventing or controlling wind or water erosion in agriculture, land development and construction.
F
FUNGI: A group of diverse and widespread
unicellular and multicellular eukaryotic organisms. Some species are important
in the decomposition of plant litter.
G
H
HEAVY METALS:
Metallic elements with high atomic weights, e.g., mercury, chromium, cadmium,
arsenic, and lead. They can cause damage to living organisms at very low
concentrations and tend to accumulate in the food chain.
HYDROCARBON: An organic chemical compound consisting
only of carbon and hydrogen atoms in the gaseous, liquid or solid phase.
(Greek hydor, water + Latin, carbo, charcoal). .
I
IN SITU: In place, without excavation.
J
K
L
LEAD: Pb, atomic number
82 -- a soft heavy toxic malleable metallic element; bluish white when
freshly cut but tarnishes readily to dull gray
LNAPL: See NAPL.
LIGNIN: A complex polymer that occurs in woody material of higher plants.
It is highly resistant to chemical and enzymatic degradation. The White
Rot Fungi are known for their lignin degrading capability.
M
MINERALIZATION: The breakdown of organic
matter to inorganic materials (such as carbon dioxide and water) by bacteria
and fungi.
MYCOBACTERIUM: A genus of aerobic bacteria found in soil and water that
are capable of biodegrading multi-ring compounds such as PAHs.
N
NAPL: Non-aqueous phase liquid. This
can be lighter than water (LNAPL), or more dense than water (DNAPL).
NITRATE RESPIRATION: (dissimilatory nitrate reduction) The use of nitrate
as a terminal electron acceptor for Anaerobic Respiration. This process
occurs under Anaerobic or Micoaerophilic conditions. Not all bacteria
are capable of this form of metabolism and the nitrate may not be reduced
completely to nitrogen gas (stopping at nitrite, for example). When
the nitrate is reduced to gaseous forms the process is called Dentrification.
This can sometimes be used to remove nitrate or nitrite from liquid
wastes.
O
ORGANIC PUMP: Uptake of large quantities
of water by plant (trees) roots and translocation into the atmosphere
to reduce a flow of water. Used to keep contaminated groundwater from
reaching a body
of water, or to keep surface water from seeping into a capped landfill
and forming leachate.
P
PAH: Polynuclear aromatic
hydrocarbon. Multi-ring compounds found in fuels, oils, and creosote.
These are also common combustion products.
PCBs: Oily, persistent substance formerly manufactured
for use in electrical equipment, primarily as a dielectric in capacitors.
Banned from use in the manufacture of equipment in 1979 after research
showed that PCBs cause skin disease and liver damage, and are a suspected
carcinogen. See dielectric.
PCE: (Perchloroethylene): Tetrachloroethylene.
PCP: Pentachlorophenol.
PHYTOREMEDIATION: Use of plants to remediate
contaminated soil or groundwater.
PHYTOSTABILIZATION: Use of soil amendments
and plants to reduce bioavailability and offsite migration of contaminants.
PHYTOVOLATILIZATION: Use of plants to volatilize contaminants (solvents,
etc.) from soil or water.
Q
R
RECALCITRANT: Resistant to biodegradation.
REDOX POTENTIAL: The oxidation-reduction potential of an environment.
Measures the tendency of the environment to be reducing (donate electrons)
or oxidizing (accept electrons).
REDUCTIVE DECHLORINATION: Removal of Cl as Cl- from an organic compound
by reducing the
carbon atom from C-Cl to C-H.
REMEDIATION: (Environmental) Cleanup or other
methods used to remove or contain a toxic spill or hazardous materials
from a site.
S
SHEET PILE: A pile
in a row of piles driven side by side to retain earth or prevent water
seepage.
SHORING: (Shoring system) a structure such as a
metal, mechanical or timber shoring system that supports the sides of
an excavation and which is designed to prevent water seepage or earthen
cave-ins.
SLURRY WALL: A (Bentonite) Slurry Wall is a subsurface,
non-structural wall that acts as a barrier to the lateral flow of groundwater.
SOIL STABILIZATION: Control of the soil
at the surface to prevent the problems related to the soil being inherently
unstable. Soil stabilization often can involve controlling dust, mud,
or erosion.
SUPERFUND: Federal authority, established by the
Comprehensive Environmental Response, Compensation, and Liability Act
(CERCLA) in 1980, to respond directly to releases or threatened releases
of hazardous substances that may endanger health or welfare.
SURFACTANT: A natural or synthetic chemical that promotes the wetting,
solubilization, and emulsification of various types of organic chemicals.
T
THERMAL DESORPTION:
Waste is heated in a controlled environment to volatize organic compounds.
TRINITROTOLUENE:- explosive consisting of
a yellow crystalline compound that is a flammable toxic derivative of
toluene. Commonly known as TNT, is a constituent of many explosives, such
as amatol, pentolite, tetrytol, torpex, tritonal, picratol, ednatol, and
composition B. It has been used under such names as Triton, Trotyl, Trilite,
Trinol, and Tritolo.
TRICHLOROETHANE: TCE, a heavy colorless
highly toxic liquid used as a solvent to clean electronic components and
for dry cleaning and as a fumigant; causes cancer and liver and lung damage.
TPH: Total petroleum hydrocarbons.
U
V
VADOSE ZONE: Unsaturated
(not completely filled with water) zone lying between the earth's surface
and the top of the ground water. Also known as unsaturated zone and zone
of aeration.
VOLATILE ORGANIC COMPOUNDS (VOCs) - Organic chemicals
all contain the element carbon(C); organic chemicals are the basic chemicals
found in living things and in products derived from living things, such
as coal, petroleum and refined petroleum products. Volatile Organic chemicals
include gasoline, industrial chemicals such as benzene, solvents such
as toluene and xylene, and tetrachloroethylene (perchloroethylene, the
principal dry cleaning solvent). Many volatile organic chemicals are also
hazardous air pollutants.
W
WEATHERING: All physical and chemical changes
produced by atmospheric agents.
WHITE ROT FUNGI: Fungi that decompose all components of wood. Important
because they produce enzymes that are capable of acting on and biodegrading
a wide variety of compounds, including many pollutants.
X
XENOBIOTIC: Compound foreign to biological
systems. Often refers to human-made compounds that are resistant or recalcitrant
to biodegradation and decomposition.
XEROPHILE: Organism adapted to grow at low water potential, i.e., very
dry habitats.
Y
Z
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