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A—Scale Sound Level: A measurement
of sound approximating the sensitivity
of the human ear, used to note the
intensity or annoyance level of sounds.
Abandoned Well: A well whose use has
been permanently discontinued or
which is in a state of such disrepair
that it cannot be used for its intended
purpose.
Abatement: Reducing the degree or
intensity of, or eliminating, pollution.
Absorbed Dose: The amount of a
chemical that enters the body of an
exposed organism.
Absorption: The uptake of water or
dissolved chemicals by a cell or an
organism (as tree roots absorb dis-
solved nutrients in soil.)
Accident Site: The location of an unex-
pected occurrence, failure or loss, ei-
ther at a plant or along a transporta-
tion route, resulting in a release of
hazardous materials.
Acclimatization: The physiological and
behavioral adjustments of an organism
to changes in its environment.
Acid Deposition: A complex chemical
and atmospheric phenomenon that
occurs when emissions of sulfur and
nitrogen compounds and other sub-
stances are transformed by chemical
processes in the atmosphere, often far
from the original sources, and then de-
posited on earth in either wet or dry
form. The wet forms, popularly called
"acid rain," can fall as rain, snow, or
fog. The .dry forms are acidic gases or
p articulates.
Acid Mine Drainage: Drainage of water
from areas that have been mined for
coal or other mineral ores. The water
has a low pH because of its contact
with sulfur-bearing material and is
harmful to aquatic organisms.
Acid Neutralizing Capacity: Measure of
ability of water or soil to resist chang-
es in pH.
Acid Rain: (See: acid deposition)
Acidic: The condition of water or soil
that contains a sufficient amount of
acid substances to lower the pH below
7.0.
Action Levels: 1. Regulatory levels
recommended by EPA for enforcement
by FDA and USDA when pesticide
residues occur in food or feed commodi-
ties for reasons other than the direct
application of the pesticide. As opposed
to "tolerances" which are established
for residues occurring as a direct re
suit of proper usage, action levels are
set for inadvertent residues resulting
from previous legal use or accidental
contamination. 2. In the Superfund
program, the existence of a contami-
nant concentration in the environment
high enough to warrant action or trig-
ger a response under SARA and the
National Oil and Hazardous Substanc-
es Contingency Plan. The term is also
used in other regulatory programs.
(See: tolerances.)
Activated Carbon: A highly adsorbent
form of carbon used to remove odors
and toxic substances from liquid or
gaseous emissions. In waste treatment
it is used to remove dissolved organic
matter from waste water. It is also
used in motor vehicle evaporative con-
trol systems.
Activated Sludge: Product that results
'when primary effluent is mixed with
bacteria-laden sludge and then agi-
tated and aerated to promote biological
treatment, speeding the breakdown of
organic matter in raw sewage undergo-
ing secondary waste treatment.
Activator A chemical added to a pes-
ticide to increase its activity.
Active Ingredient: In any pesticide
product, the component that kills, or
otherwise controls, target pests. Pes-
ticides are regulated primarily on the
basis of active ingredients.
Activity Plans: Written procedures in a
school's asbestos-management plan
that detail the steps a Local Education
Agency (LEA) will follow in performing
the initial and additional cleaning,
operation and maintenance-program
tasks; periodic surveillance; and rein-
spections required by the Asbestos
Hazard Emergency Response Act
(AHERA).
Acute Exposure: A single exposure to a
toxic substance which results in severe
biological harm or death. Acute expo-
sures are usually characterized as last-
ing no longer than a day, as compared
to longer, continuing exposure over a
period of time.
Acute Tarititv: The ability of a sub-
stance to cause poisonous effects re-
sulting in severe biological harm or
death soon after a single exposure or
dose. Also, any severe poisonous effect
resulting from a single short-term
exposure to a toxic substance. (See:
chronic toxicity, toxitity.)
Adaptation: Changes in an organism's
structure or habits that help it adjust
to its surroundings.
Add-on Control Device: An air pollu-
tion control device such as carbon
absorber or incinerator that reduces
the pollution in an exhaust gas. The
control device usually does not affect
the process being controlled and thus
is "add-on" technology, as opposed to a
scheme to control pollution through
altering the basic process itself.
Adequately Wet: Asbestos-containing
material that is sufficiently mixed or
penetrated with liquid to prevent the
release of particulates.
Administrative Order On Consent: A
legal agreement signed by EPA and an
individual, business, or other entity
through which the violator agrees to
pay for correction of violations, take
the required corrective or cleanup
actions, or refrain from, an activity. It
describes the actions to be taken, may
be subject to a comment period, applies
to civil actions, and can be enforced in
court.
Administrative Order A legal docu-
ment signed by EPA directing an indi-
vidual, business, or other entity to take
corrective action or refrain from an
activity'. It describes the violations and
actions to be taken, and can be en-
forced in court. Such orders may be
issued, for example, 'as a result of an
administrative complaint whereby the
respondent is ordered to pay a penalty
for violations of a statute.
Administrative Procedures Act: A law
that spells out procedures and requir'
ements related to the promulgation of
regulations.
Administrative Record: All documents
which EPA considered or relied on in
selecting the response action at a
Superfund site, culminating in the
record of decision for remedial action;
an action memorandum for removal
actions.
Adsorption: An advanced method of
treating waste in which activated car-
bon removes organic matter from
wastewater.
Adulterants: Chemical impurities or
substances that by law do not belong
in a food, or pesticide.
Adulterated: 1. Any pesticide whose
strength or purity falls below the qual-
ity stated on its label. 2. A food.feed, or
product that contains illegal pesticide
residues.
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Advanced Treatment: A level of waste-
water treatment more stringent than
secondary treatment; requires an 85-
percent reduction in conventional pol-
lutant concentration or a significant
reduction in nonconventipnal pollut-
ants.
Advanced Wastewater Treatment: Any
treatment of sewage that goes beyond
the secondary or biological water treat-
ment stage and includes the removal of
nutrients such as phosphorus and
nitrogen and a high percentage of sus-
pended solids. (See: primary, secondary
treatment.)
Advisory. A non-regulatory document
that communicates risk information to
those who may have to make risk man-
agement decisions.
Aerated Lagoon: A holding and/or
treatment pond that speeds up the
natural process of biological decomposi-
tion of organic waste by stimulating
the growth and activity of bacteria that
degrade organic waste.
Aeration: A process which promotes
biological degradation of organic mat-
ter in water. The process may be pas-
sive (as when waste is exposed to air),
or active (as when a mixing or bub-
bling device introduces the air).
Aeration Tank: A chamber used to in-
ject air into water.
Aerobic Treatment: Process by which
microbes decompose complex organic
compounds in the presence of oxygen
and use the liberated energy for re-
production and growth. (Such process-
es include extended aeration, trickling
filtration, and rotating biological
contactors.)
Aerobic: Life or processes that require,
or are not destroyed by, the presence of
oxygen. (See: anaerobic.)
Aerosol: A suspension of liquid or solid
particles in a gas.
Affected Public The people who live
and/or work near a hazardous waste
site or other source of pollutant emis-
sions.
Afterburner: In incinerator technology,
a burner located so that the combus-
tion gases are made to pass through its
flame in order to remove smoke and.
odors. It may be attached to or be
separated from the incinerator proper.
Age Tank: A tank used to store a
chemical solution of known concentra-
tion for feed .to a chemical feeder. Also
called a day tank.
Agent Orange: A toxic herbicide and
defoliant used in the Vietnam conflict,
containing 2,4,5-trichlorophenoxyacetic
acid (2,4,5-T) and 2-4 dichlorophenoxy-
acetic acid (2,4-D) with trace amounts
of dioxin.
Agricultural Pollution: Farming
wastes, including runoff and leaching
of pesticides and fertilizers; erosion
and dust from plowing; improper dis-
posal of animal manure and carcasses;
crop residues, and debris.
Agro-ecosystem: Land used for crops,
pasture, and livestock; the adjacent
uncultivated land that supports other
vegetation and wildlife; and the associ-
ated atmosphere, the underlying soils,
groundwater, and drainage networks.
AHERA Designated Person (ADP): A
person designated by a Local Educa-
tion Agency to ensure that the AHERA
requirements for asbestos management
and abatement are properly imple-
mented.
Air Binding: Situation where air enters
the filter media and harms both the
filtration and backwash processes.
Air Changes Per Hour (ACH> The
movement of a volume of air in a given
period of time; if a house has one air
change per hour, it means that all of
the air in the house will be replaced in
a one-hour period.
Air Contaminant: Any particulate mat-
ter, gas, or combination thereof, other
than water vapor. (See: air pollutant.)
Air Curtain: A method of containing oil
spills. Air bubbling through a perfo-
rated pipe causes an upward water
flow that slows the spread of oil. It
«•*" also be used to stop fish from en-
tering polluted water.
Air Gap: Open vertical gap or empty
space that separates drinking water
supply to be protected from another
water system in a treatment plant or
other location. The open gap protects
the drinking water from contamination
by backflow or backsiphonage.
Air Mass: A large volume of air with
certain meteorological or polluted char-
acteristics, e,g, a heat inversion or
smogginess, while in one location. The
characteristics cfi" change as the air
mass moves away.
Air Monitoring: (See: monitoring)
Air Padding: Pumping dry air into a
container to assist with the withdrawal
of liquid or to force a liquified gas such
as chlorine out of the container.
Air Plenum: Any space used to convey
air in a building, furnace, or structure.
The space above a suspended ceiling is
often used as an air plenum.
Air Pollutant: Any substance in air
that could, in high enough concentra-
tion, harm man, other animals, vegeta-
tion, or material. Pollutants may in-
clude almost any natural or artificial
composition of airborne matter capable
of being airborne. They may be in the
form of solid particles, liquid droplets,
gases, or in combination thereof. Gen-
erally, they fall into two main groups:
(1) those emitted directly from identi-
fiable sources and (2) those produced
in the air by interaction between two
or more primary pollutants, or by reac-
tion with normal atmospheric constitu-
ents, with or without photoactivation.
Exclusive of pollen, fog, and dust,
which are of natural origin, about 100
contaminants have been identified and
fall into the following categories: sol-
ids, sulfur compounds, volatile organic
chemicals, nitrogen compounds, oxygen
compounds, halogen compounds, radio-
active compounds, and odors.
Air Pollution Episode: A period of ab-
normally high concentration of air
pollutants, often due to low winds and
temperature inversion, that can cause
illness and death. (See: episode, pollu-
tion.)'
Air Pollution Control Device: Mecha-
nism or equipment that cleans emis-
sions generated by an incinerator by
removing pollutants that would other-
wise be released to the atmosphere.
Air Pollution: The presence of contami-
nant or pollutant substances in the air
that do not disperse properly and in-
terfere with human health or welfare,
or produce other harmful environmen-
tal effects.
Air Quality Control Region: Federally
designated area that is required to
meet and maintain federal ambient air
quality standards. May include nearby
locations in the same state or nearby
states that share common air pollution
problems-
Air Quality Criteria: The levels of
pollution and lengths of exposure
above which adverse health and wel-
fare effects may occur.
Air Quality Standards: The level of
pollutants prescribed by regulations
that may not be exceeded during a
given time in a defined area.
Air Stripping: A treatment system that
removes volatile organic compounds
(VOCs) from contaminated ground
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water or surface water by forcing an
airstream through the water and cau-
sing the compounds to evaporate.
Air Tories: Any air pollutant for which
a national ambient air quality stan-
dard (NAAQS) does not exist (i.e., ex-
cluding ozone, carbon monoxide, PM-
10, sulfur dioxide, nitrogen oxide) that
may reasonably be anticipated to cause
cancer, developmental effects, repro-
ductive dysfunctions, neurological dis-
orders, heritable gene mutations, or
other serious or irreversible chronic or
acute health effects in humans.
Airborne Particulates: Total suspended
particulate matter found in the atmo-
sphere as solid particles or liquid drop-
lets. Chemical composition of
particulates varies widely, depending
on location and time of year. Airborne
particulates include: windblown dust,'
emissions from industrial processes,
smoke from the burning of wood and
coal, and motor vehicle or non-road
engine exhausts, exhaust of motor
vehicles.
Airborne Release: Release of any chem-
ical into the air.
Alachlor A herbicide, marketed under
the trade name Lasso, used mainly to
control weeds in corn and soybean
fields.
Alar Trade name for daminozide, a
pesticide that makes apples redder,
firmer, and less likely to drop off trees
before growers are ready to pick them.
It is also used to a lesser extent on
peanuts, tart cherries, concord grapes,
and other fruits.
Aldicarb: An insecticide sold under the
trade name Temik. It ia made from
ethyl isocyanate.
Algae: Simple rootless plants that grow
in sunlit waters in proportion to the
amount of available nutrients. They
can affect water quality adversely by
lowering the dissolved oxygen in the
water. They are food for fish and small
aquatic animals.
Algal Blooms: Sudden spurts of algal
growth, which can affect water quality
adversely and indicate potentially
hazardous changes in local water
chemistry.
Algicide: Substance or chemical used to
specifically to kill or control algae.
Alkaline: The condition of water or soil
which contains a suffice nt amount of
alkali substance to raise the pH above
7.0.
Alkalinity: The capacity of water to
neutralize acids.
Alluvial: Relating to and/or sand de-
posited by flowing water.
Alternate Method: Any method of sam-
pling and analyzing for an air pollut-
ant that is not a reference or equiva-
lent method but that has been demon-
strated in specific cases-to EPA's satis-
faction-to produce results adequate for
compliance monitoring.
Alternative Fuels: Substitutes for tra-
ditional liquid, oil-derived motor vehi-
cle fuels like gasoline and diesel. In-
cludes methanol, ethanol, compressed
natural gas, and others.
Alternative Remedial Contract Strate-
gy Contractors: Government contrac-
tors who provide project management
and technical services to support reme-
dial response activities at National
Priorities List sites.
Ambient Air Any unconfined portion
of the atmosphere: open air, surround-
ing air.
Ambient Air Quality Standards: (See:
Criteria Pollutants and National Ambi-
ent Air Quality Standards.)
Ambient Temperature: Temperature of
. the surrounding air or other medium.
Amprometric Titration: A way of mea-
suring concentrations of certain sub-
stances in water using an electric cur-
rent that flows during a chemical reac-
tion.
Anaerobic A life or process that occurs
in, or is not destroyed by, the absence
of oxygen.
Anaerobic Decomposition: Reduction of
the net energy level and change in
chemical composition of organic matter
caused by microorganisms in an oxy-
gen-free environment.
Animal Studies: Investigations using
animals as surrogates for humans with
the expectation that the results are
pertinent to humans.
Antagonism: Interference or inhibition
of the effect of one chemical by the
action of another.
Antarctic "Ozone Hole": Refers to the
seasonal depletion of ozone in a large
area over Antarctica.
Anti-Degradation Clause: Part of fed-
eral air quality and water quality
requirements prohibiting deterioration,
where pollution levels are above the
legal limit.
Applicable or Appropriate Require-
ments (ARARs): Any state or federal
statute that pertains to protection of
human life and the environment in
addressing specific conditions or use of
a particular cleanup technology at a
Super-fund site,
Aqueous: Something made up of, simi-
lar to, or containing water.
Aquifer An underground geological
formation, or group of formations, con-
taining usable amounts of ground water
that can supply wells and springs.
Architectural Coatings: Coverings such
as paint and roof tar that are used on
enteriors of buildings.
Area of Review: In the UIC program,
the area surrounding an injection well
that is reviewed during the permitting
process to determine if flow between
aquifers will be induced by the injec-
tion operation.
Area Source: Any small source of non-
natural air pollution that is released
over a relatively small area but which
cannot be classified as a point source.
Such sources may include vehicles and
other small engines, small businesses
and household activities.
Aromatic: A type of hydrocarbon, such
as benzene or toluene, added to gaso-
line hi order to increase octane. Some
aromatics are toxic.
Arsenicals: Pesticides containing ar-
senic.
Artesian (Aquifer or Well): Water held
under pressure hi porous rock or soil
confined by impermeable geological
formations.
Asbestos: A mineral fiber that can
pollute air or water and cause cancer
or asbestosis when inhaled. EPA has
banned or severely restricted its use in
manufacturing and construction.
Asbestos Abatement: Procedures to
control fiber release from asbestos-con-
taining materials in a building or to
remove them entirely, including remov-
al, encapsulation, repair, enclosure,
encasement, and operations and main-
tenance programs.
Asbestos-Containing Waste Materials
(ACWM): Mill tailings or any waste
that contains commercial asbestos and
is generated by a source covered by the
Clean Air Act Asbestos NESHAPS.
Asbestosis: A disease associated with
inhalation of asbestos fibers. The dis-
ease makes breathing progressively
more difficult and can be fatal.
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Asbestos Program Manager A building
owner or designated representative
who supervises all aspects of the facili-
ty asbestos management and control
program.
Ash: The mineral content of a product
remaining after complete combustion.
Assay; A test for a specific chemical or
effect.
Assessment: In the asbestos-in-schools
program, the evaluation of the physical
condition and potential for damage of
all friable asbestos containing materi-
als and thermal insulation systems.
Assimilation: The ability of a body of
water to purify itself of pollutants.
Assimilative Capacity: The capacity of
a natural body of water to receive
waste waters or toxic materials without
deleterious effects and without damage
to aquatic life or humans who consume
the water.
Association of Boards of Certification:
An international organization repre-
senting boards which certify the opera-
tors of waterworks and wastewater
facilities.
Attainment Area: An area considered
to have air quality as good as or better
than the national ambient air quality
standards as defined in the Clean Air
Act. An area may be an attainment
area for one pollutant and a non-at-
tainment area for others.
Attenuation: The process by which a
compound is reduced in concentration
over time, through absorption, adsorp-
tion, degradation, dilution, and/or
transformation.
Attractant: A chemical or agent that
lures insects or other pests by stimu-
lating their sense of smell.
Attrition: Wearing or grinding down of
a substance by friction. Dust from
such processes contributes to air pollu-
tion.
Availability Session: Informal meeting
at a public location where interested
citizens can talk-with EPA and state
officials on a one-to-one basis.
Available Chlorine: A measure of the
amount of chlorine available in chlori-
nated lime, hypochlorite compounds,
and other materials used as a source of
chlorine when compared with that of
liquid or gaseous chlorines.
B
Back Pressure: A pressure that can
cause water to backflow into the water
supply when a user's waste water
system is at a higher pressure than
the public system.
Backflow/Back Siphonage: A reverse
flow condition created by a difference
in water pressures that causes water
to flow back into the distribution pipes
of a drinking water supply from any
source other than the intended one.
Background Level: In air pollution con-
trol, the concentration of air pollutants
in' a definite area during a fixed period
of time prior to the starting up or on
the stoppage of a source of emission
under control. In . toxic substances
monitoring, the average presence in
the environment, originally referring to
naturally occurring phenomena.
Backwashing: Reversing the flow of
water back through the filter media to
remove entrapped solids.
BACT-Best Available Control Technol-
ogy: An emission limitation based on
the maximum degree of emission re-
duction (considering energy, environ-
mental, and economic impacts) achiev-
able through application of production
processes and available methods, sys-
tems, and techniques. BACT does not
permit emissions in excess of those
allowed under any applicable Clean
Air Act provisions. Use of the BACT
concept is allowable on a case by case
basis for major new or modified emis-
sions .sources in attainment areas and
applies to each regulated pollutant.
Bacteria: (Singular bacterium) Micro-
scopic living organisms that can aid in
pollution control by metabolizing or-
ganic matter in sewage, oil spills or
other pollutants. However, bacteria in
soil, water or air can also cause hu-
man, animal and plant health prob-
lems.
Baffle: A flat board or plate, deflector,
guide, or similar device constructed or
placed in flowing water or slurry sys-
tems to cause more uniform flow veloc-
ities to absorb energy and to divert,
guide, or agitate liquids.
<;
Raff|a Chamber In incinerator design,
a chamber designed to promote the set-
tling of fly ash and coarse particulate
matter by Changing the direction
and/or reducing the velocity of the
gases produced by the combustion of
the refuse or sludge.
(greater than 20 microns in diameter)
particles. This device operates like the
bag of an electric vacuum cleaner,
passing the air and smaller particles
while entrapping the larger ones.
Bailer A long pipe with a valve at the
lower end, used to remove slurry from
the bottom or side of a well as it is
being drilled.
Ruling- Compacting solid waste into
blocks to reduce volume and simplify
handling.
Ballistic Separator A machine that
sorts organic from inorganic matter for
composting.
Band Application: The spreading of
chemicals over, or next to, each row of
plants in a field.
Banking: A system for recording quali-
fied air emission reductions for later
use in bubble, offset, or netting trans-
actions. (See: emissions trading.)
Bar Screen: In wastewater treatment,
a device used to remove large solids.
Barrier Coating(s): A layer of a materi-
al that obstructs or prevents passage
of something through a surface that is
to be protected, e.g. grout, caulk, or
various sealing compounds; sometimes
used with polyurethane membranes to
•prevent corrosion or oxidation of metal
surfaces, chemical impacts on various
materials, or, for example, to prevent
radon infiltration through walls,
cracks, or joints in a house.
Basal Application: In pesticides, the
application of a chemical on plant
stems or tree trunks, just above the soil
line.
Bed Load: Sediment particles resting
on or near the channel bottom that are
pushed or rolled along by the flow of
water.
BEN: EPA's computer model for ana-
lyzing a violator's economic gain from
not complying with the law.
Bench
Filter: Large fabric bag,
usually made of glass fibers, used to
eliminate intermediate and large
i Testa: Laboratory testing
of potential cleanup technologies (See:
treatability studies.)
Beryllium: An airborne metal hazard-
ous to human health when inhaled. It
is discharged by machine shops, ce-
ramic and propellant plants, and
foundries.
Best Available Control Measures
(BACM): A term used to refer to the
most effective measures (according to
EPA guidance) for controlling small or
dispersed participates from sources
such as roadway dust, soot and ash
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from woodstoves and open burning of
rush, timber, grasslands, or trash.
Beat Demonstrated Available Technolo-
gy (BDAT): As identified by EPA, the
most effective commercially available
means of treating specific types of
hazardous waste. The BDATs may
change with advances in treatment
technologies.
Best Management Practice (BMP):
Methods that have been determined to
be the most effective, practical means
of preventing or reducing pollution
from non-point sources.
Bimetal: Beverage containers with
steel bodies and aluminum tops; han-
dled differently from pure aluminum in
recycling.
Bioaccumulants: Substances that in-
crease in concentration in living organ-
isms as they take in contaminated air,
water, or food because the substances
are very slowly metabolized or ex-
creted. (See: biological magnification.)
Bioassay: Study of living organisms to
measure the effect of a substance, fac-
tor, or condition by comparing before-
and-after exposure or other data.
Biochemical Oxygen Demand (BOD): A
measure of the amount of oxygen con-
sumed in the biological processes that
break down organic matter in water.
The greater the BOD, the greater the
degree of pollution.
Bioconcentration: The accumulation of
a chemical in tissues of a fish or other
organism to levels greater than in the
surrounding medium.
Biodegradable: Capable of decomposing
rapidly under natural conditions.
Biodiversity: Refers to the variety and
variability among living organisms and
the ecological complexes in which they
occur. Diversity can be defined as the
number of different items and their
relative frequencies. For biological
diversity, these items are organized at
many levels, ranging from complete
ecosystems to the biochemical struc-
tures that are the molecular basis of
heredity. Thus, the term encompasses
different ecosystem, species, and genes.
Biological Control: In pest control, the
use of animals and organisms that eat
or otherwise kill or put-compete pests.
Biological Magnification: Refers to the
process whereby certain substances
such as pesticides or heavy metals
move up the food chain, work their
way into rivers or lakes, and are eaten
by aquatic organisms such as fish,
which in turn are eaten by large birds,
animals or humans. The substances
become concentrated in .tissues or in-
ternal organs as they move up the
chain. (See: bioaccumulative.)
Biological Oxidation: Decomposition of
complex organic materials by microor-
ganisms. Occurs in self-purification of
water bodies and in activated sludge
wastewater treatment.
Biological Oxygen Demand (BOD): An
indirect measure of the concentration
of biologically degradable material
present in organic wastes. It usually
reflects the amount of oxygen con-
sumed in five days by biological pro-
cesses breaking down organic waste.
Biological Treatment: A treatment
technology that uses bacteria to con-
sume organic waste.
Biologicals: Vaccines, cultures and
other preparations made from living
organisms and their products, intended
for use in diagnosing, immunizing, or
treating humans or animals, or in
related research.
Biomass: All of the living material in a
given area; often refers to vegetation.
Biome: Entire community of living
organisms in a single major ecological
area. (See: biotic community.)
BJomonitoring: 1. The use of living
organisms to test the suitability of
effluents for discharge into receiving
waters and to test the quality of such
waters downstream from the dis-
charge. 2. Analysis of blood, urine,
tissues, etc., to measure chemical expo-
sure in humans.
Bioremediation: Use of living organ-
isms to clean up oil spills or remove
other pollutants from soil, water, or
wastewater; use of organisms such as
non-harmful insects to remove agricul-
tural pests or counteract diseases of
trees, plants, and garden soil.
Biosphere: The portion of Earth and its
atmosphere that can support life.
Biostabilizer: A machine that converts
solid waste into compost by grinding
and aeration.
Biota: The animal and plant life of a
given region.
Biotechnology: Techniques that use
living organisms or parts of organisms
to produce a variety of products (from
medicines to industrial enzymes) to
improve plants or animals or to devel-
op microorganisms to remove toxics
from bodies of water, or act as pesti-
cides.
Biotic Community: A naturally occur-
ring assemblage of plants and animals
that live in the same environment and
are mutually sustaining and interde-
pendent.(See: biome.)
Biotransformation: Conversion of a
substance into other compounds by
organisms; includes biodegredation.
Blackwater. Water that contains ani-
mal, human, or food waste.
Blood Products: Any product derived
from human blood, including but not
limited to blood plasma, platelets, red
or white corpuscles, and derived li-
censed products such as interferon.
Bloom: A proliferation of algae and/or
higher aquatic plants in a body of
water; often related to pollution, espe-
cially when pollutants accelerate
growth.
BODS: The amount of dissolved oxygen
consumed in five days by biological
processes breaking down organic mat-
ter.
Bog: A type of wetland that accumu-
lates appreciable peat deposits. Bogs
depend primarily on precipitation for
their water source, and are usually
acidic and rich in plant residue with a
conspicuous mat of living green moss.
Boom: 1. A floating device used to
contain oil on a body of water. 2. A
piece of equipment used to apply pes-
ticides from a tractor or truck.
Botanical Pesticide: A pesticide whose
active ingredient is a plant-produced
chemical such as nicotine or strych-
nine. Also called a plant-derived pesti-
cide.
Bottle Bill: Proposed or enacted leg-
islation which requires a returnable
deposit on beer or soda containers and
provides for retail store or other re-
demption. Such legislation is designed
to discourage use of throwaway con-
tainers.
Bottom Ash: The non-airborne combus-
tion residue from burning pulverized
coal in a boiler; the material which
falls to the bottom of the boiler and is
removed mechanically; a concentration
of the non-combustible materials,
which may include toxics.
Bottom Land Hardwoods: Forested
freshwater wetlands adjacent to rivers
in the southeastern United States,
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6
especially valuable for wildlife breed-
ing, nesting and habitat.
Brackish: Mixed fresh and salt water.
Breakpoint Chlorination: Addition of
chlorine to water until the chlorine
demand has been satisfied.
Breakthrough: A crack or break in a
filter bed that allows the passage of
floe or particulate matter through a
filter; will cause an increase in filter
effluent turbidity.
Brine Mud: Waste material, often asso-
ciated with well-drilling or mining,
composed of mineral salts or other
inorganic compounds.
Broadcast Application: The spreading
of pesticides over an entire area.
Bubble: A system under which existing
emissions sources can propose alter-
nate means to comply with a set of
emissions limitations; under the bubble
concept, sources can control more than
required at one emission point where
control costs are relatively low in re-
turn for a comparable relaxation of
controls at a second emission point
where costs are higher.
Bubble Policy: (See: emissions trading.)
Buffer A solutiuon or liquid whose
chemical makeup neutralizes acids or
bases without a great change in pH.
Buffer Strips: Strips of grass or other
erosion-resisting vegetation between or
below cultivated strips or fields.
Building Cooling Load: The hourly
amount of heat that must be removed
from a building to maintain indoor
comfort (measured in British Thermal
Units BTUs).
Bulk Sample: A small portion (usually
thumbnail size) of a suspect asbestos-
containing building material collected
by an asbestos inspector for laboratory
analysis to determine asbestos content.
Bulky Waste: Large items of waste
materials, such as appliances, furni-
ture, large auto parts, trees, stumps.
Burial Ground (Graveyard): A disposal
site for radioactive waste materials
that uses earth or water as a shield.
By-product: Material, other than the
principal product, generated as a con-
sequence of an industrial process.
Cadmium (Cd> A heavy metal element
that accumulates in the environment.
Cancellation: Refers to Section 6 (b) of
the Federal Insecticide, Fungicide and
Rodenticide Act (FIFRA) which autho-
rizes cancellation of a pesticide regis-
tration if unreasonable adverse effects
to the environment and public health
develop when a product is used accord-
ing to widespread and commonly recog-
nized practice, or if its labeling or
other material required to be submit-
ted does not comply with FIFRA provi-
sions.
Cap: A layer of clay, or other imperme-
able material installed over the top of
a closed landfill to prevent entry of
rainwater and minimize leachate.
Capacity Assurance Flan: A statewide
plan which supports a state's ability to
manage the hazardous waste generat-
ed within its boundaries over a twenty
year period.
Capillary Action: Movement of water
through very small spaces to to molec-
ular forces called capillary forces.
Capillary Fringe: The porous matrial
just above the water table which may
hold water by capillarity (a property of
surface tension that draws water up-
wards) in the smaller void spaces.
Capture Efficiency: The fraction of
organic vapors generated by a process
that is directed to an abatement or re-
covery device.
Carbon Absorber An add-on control
device that uses activated carbon to
absorb volatile organic compounds
from a gas stream. (The VOCs are
later recovered from the carbon.)
Carbon Adsorption: A treatment sys-
tem that removes contaminants from
ground water or surface water by forc-
ing it through tanks containing acti-
vated carbon treated to attract the con-
taminants.
Carbon Monoxide (CO): A colorless,
odorless, poisonous gas produced by
incomplete fossil fuel combustion.
Carboxyhemoglobin: Hemoglobin in
which the iron is bound to carbon
monoxide (CO) instead of oxygen.
Carcinogen: Any substance that can
cause or aggravate cancer.
Carrier The inert liquid or solid mate-
rial added to an active ingredient in a
pesticide.
Carrying Capacity: 1. In recreation
management, the amount of use a
recreation area can sustain without
loss of quality. 2. In wildlife manage-
ment, the Tnn-rimiiTn number of ani-
mals an area can support during a
given period.
CAS Registration Number A number
asigned by the Chemical Abstract Ser-
vice to identify a chemical.
Cask: A thick-walled container (usually
lead) used to transport radioactive
material. Also called a coffin.
Catalyst: A substance that changes the
speed or yield of a chemical reaction
without being consumed or chemically
changed by the chemical reaction.
Catalytic Converter. An air pollution
abatement device that removes pollut-
ants from motor vehicle exhaust, either
by oxidizing them into carbon dioxide
and water or reducing them to nitro-
gen and oxygen.
Catalytic Incinerator A control device
that oxidizes volatile organic com-
pounds (VOCs) by using a catalyst to
promote the combustion process. Cata-
lytic incinerators require lower temper-
atures than conventional thermal in-
cinerators, thus saving fuel and other
costs.
Categorical Exclusion: A class of ac-
tions which either individually or cu-
mulatively would not have a signifi-
cant effect on the human environment
and therefore would not require prepa-
ration of an environmental assessment
or environmental impact statement
under the National Environmental
Policy Act (NEPA).
Categorical Pretreatment Standard: A
technology-based effluent limitation for
an industrial facility discharging into
a municipal sewer system. Analogous
in stringency to Best Availability Tech-
nology (BAT) for direct dischargers.
Cathodic Protection: A technique to
prevent corrosion of a metal surface by
making it the cathode of an electro-
chemical cell.
Cavitation: The formation and collapse
of gas pockets or bubbles on the blade
of an impeller or the gate of a' valve;
collapse of these pockets or bubbles
drives water with such force that it
can cause pitting of the gate or valve
surface.
Cells: 1. In solid waste disposal, holes
where waste is dumped, compacted,
and covered with layers of dirt on a
daily basis. 2. The smallest structural
part of living matter capable of func-
tioning as an independent unit.
Cementitious: Densely packed and
nonfibrous friable materials.
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Central Collection Point: Location were
a generator of regulated medical waste
consolidates wastes originally generat-
ed at various locations in his facility.
The wastes are gathered together for
treatment on-site or for transportation
elsewhere for treatment and/or dispos-
al. This term could also apply to com-
munity hazardous waste collections, in-
dustrial and other waste management
systems.
Centrifugal Collector A mechanical
system using centrifugal force to re-
move aerosols from a gas stream or to
de-water sludge.
Channelization: Straightening and
deepening streams so water will move
faster, a marsh-drainage tactic that
can-interfere with waste assimilation
capacity, disturb fish and wildlife habi-
tats, and aggravate flooding.
Characteristic: Any one of the four
categories used in defining hazardous
waste: ignitability, corrosivity, reactivi-
ty, and toxicity.
Chemical Oxygen Demand (COD): A
measure of the oxygen required to
oxidize all compounds, both organic
and inorganic, in water.
Chemical Treatment: Any one of a
variety of technologies that use chemi-
cals or a variety of chemical processes
to treat waste.
Chemnet: Mutual aid network of chem-
ical shippers and contractors that as-
signs a contracted emergency response
company to provide technical support
if a representative of the firm whose
chemicals are involved in an incident
is not readily available.
Chemoeterilant: A chemical that con-
trols pests by preventing reproduction.
Chemtrec: The industry-sponsored
Chemical Transportation Emergency
Center; provides information and/or
emergency assistance to emergency
responders.
Chilling Effect The lowering of the
Earth's temperature because of in-
creased particles in the air blocking
the sun's rays. (See: greenhouse ef-
fect.)
Chisel Plowing: Preparing croplands by
using a special implement that avoids
complete inversion of .the soil as with
conventional plowing. Chisel plowing
can leave a protective cover or crops
residues on the soil surface to help
prevent erosion and improve filtration.
Chlorinated Hydrocarbons: These in-
clude a class of persistent, broad-spec-
trum insecticides that linger in the
environment and accumulate in the
food chain. Among them are DDT, al-
drin, dieldrin, heptachlor, chlordane,
lindane, endrin, mi rex, hexachloride,
and toxaphene. Other examples in-
clude TCE, used as an industrial sol-
vent.
Chlorinated Solvent: An organic sol-
vent containing chlorine atoms, e.g.,
methylene chloride and 1,1,1-trichlo-
romethane, used in aerosol spray con-
tainers and in highway paint.
Chlorination: The application of chlo-
rine to drinking water, sewage, or
industrial waste to disinfect or to oxi-
dize undesirable compounds.
Chlorinator A device that 'adds chlo-
rine, in gas or liquid form, to water or
sewage to kill infectious bacteria.
Chlorine-Contact Chamber That part
of a water treatment plant where efflu-
ent is disinfected by chlorine.
Chlorofluorocarbons (CFCs): A family
of inert, nontoxic, and easily liquified
chemicals used in refrigeration, air
conditioning, packaging, insulation, or
as solvents and aerosol propellants.
Because. CFCs are not destroyed in the
lower atmosphere they drift into the
upper atmosphere where their chlorine
components destroy ozone.
Chlorophenoxy: A class of herbicides
that may be found in domestic water
supplies and cause adverse health
effects.
Chkntu: Discoloration of normally
green plant parts caused by disease,
lack of nutrients, or various air pollut-
ants.
Cholineflterase: An enzyme found in
animala that regulates nerve impulses.
Cholineaterase inhibition is associated
with a variety of acute symptoms such
as nausea, vomiting, blurred vision,
stomach cramps, and rapid heart rate.
Chromium: (See: heavy metals.)
Chronic Effect: An adverse effect on a
human or animal in which symptoms
recur frequently or develop slowly over
a long period of time.
Chrome Toxicity: The capacity of a
substance to cause long-term poisonous
human health effects. (See: acute toxic-
ity.)
Circle of Tnfln«m«a- The circular outer
edge of a deppression produced in the
water table by the pumping of water
from a well. (See: cone of depression.)
Cistern: Small tank or storage facility
used to store water for a home or farm;
often used to store rain water.
Clarification: Clearing action that
occurs during wastewater treatment
when solids settle out. This is often
aided by centrifugal action and chemi-
cally induced coagulation in wastewat-
er.
Clarifier A tank in which solids settle
to the bottom and are subsequently re-
moved as sludge.
Class I Area: Under the Clean Air Act.
a Class I area is one in which visibility
is protected more stringently than
under the national ambient air quality
standards; includes national parks,
wilderness areas, monuments, and
other areas of special national and cul-
tural significance.
Clay Soil: Soil material containing
more than 40 percent clay, less than
45 percent sand, and less than 40
percent silt.
Clean Coal Technology: Any technology
not in widespread use prior to the
Clean Air Act amendments of 1990.
This Act will achieve significant reduc-
tions in pollutants associated with the
burning of coal.
Clean Fuels: Blends or substitutes for
gasoline fuels, including compressed
natural gas, methanol, ethanol, liqui-
fied petroleum gas, and others.
Cleanup: Actions taken to deal with a
release or threat of release of a haz-
ardous substance that could affect
humans and/or the environment. The
term "cleanup" is sometimes used in-
terchangeably with the terms remedial
action, removal action, response action,
or corrective action.
Clear Cut: Harvesting all the trees in
one area at one time, a practice that
can encourage fast rainfall or
snowmelt runoff, erosion, sedimenta-
tion of streams and lakes, flooding, and
destroys vital habitat.
Clear Well: A reservoir for storing
filtered water of sufficient quantity to
prevent the need to vary the filtration
rate with varatioins in demand. Also
used to provide chlorine contact time
for disinfection.
Cloning: In biotechnology, obtaining a
group of genetically identical cells from
a single cell; making identical copies of
a gene.
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8
Closed-Loop Recycling: Reclaiming or
reusing wastewater for non-potable
purposes in an enclosed process.
Closure: The procedure a landfill oper-
ator must follow when a landfill reach-
es its legal capacity for solid waste:
ceasing acceptance of solid waste and
placing a cap on the landfill site.
Coagulation: Clumping of particles in
wastewater to settle out impurities,
often induced by chemicals such as
lime, alum, and iron salts.
Coal Cleaning Technology: Precombus-
tion process by which coal is physically
or chemically treated to remove some
of its sulfur so as to reduce sulfur
dioxide emissions. .
Coal Gasification; Conversion of coal to
a gaseous product by one of several
available technologies.
Coastal Zone: Lands and waters adja-
cent to the coast that exert an influ-
ence on the uses of the sea and its
ecology, or whose uses and ecology are
affected by the sea.
Coefficient of Haze (COH): A measure-
ment of visibility interference in the
atmosphere.
Co-fire: Burning of two fuels in the
same combustion unit, e.g., coal and
natural gas, or oil and coal.
Coke Oven: An industrial process
which converts coal into coke, one of
the basic materials used in blast fur-
naces for the conversion of iron ore
into iron.
Gold Temperature CO: A standard for
automobile carbon monoxide (CO)
emissions to be met at a low tempera-
ture (i.e. 20 degrees Fahrenheit). Con-
ventional automobile catalytic conver-
ters are less efficient upon start-up at
low temperatures.
Colifonn Index: A rating of the purity
of water based on a count of fecal bac-
teria.
Colifonn Organism: Microorganism
found in the intestinal tract of humans •
and animals. Their presence in water
indicates fecal pollution and potentially
adverse contamination by pathogens.
Collector Sewers: Pipes used to collect
and carry wastewater from individual
sources to an interceptor sewer that
will carry it to a treatment facility.
Colloids: Very small, finely divided
solids (that do not dissolve) that re-
main dispersed in a liquid for a long
time due to their small size and electri-
cal charge.
Combined Sewer Overflow: Discharge
of a mixture of storm water and do-
mestic waste when the flow capacity of
a sewer system is exceeded during
rainstorms.
Combined Sewers: A sewer system that
carries both sewage and storm-water
runoff. Normally, its entire flow goes to
a waste treatment plant, but during a
heavy storm, the volume of water may
be so great as to cause overflows of
untreated mixtures of storm water and
sewage into receiving waters. Storm-
water runoff may also carry toxic
chemicals from industrial areas or
streets into the sewer system.
Combustion: 1. Burning, or rapid oxi-
dation, accompanied by release of ener-
gy in the form of heat and light. A
basic cause of air pollution. 2. Refers to
controlled burning of waste, in which
heat chemically alters organic com-
pounds, converting them into stable
inorganics such as carbon dioxide and
water.
Combustion Chamber The actual com-
partment where waste is burned in an
incinerator.
Combustion Product: Substance pro-
duced during the burning or oxidation
of a material.
Command Poet: Facility located at a
safe distance upwind from an accident
site, where the on-scene coordinator,
responders, and technical representa-
tives make response decisions, deploy
manpower and equipment, maintain
liaison with news media, and handle
communications.
Comment Period: Time provided for
the public to review and comment on a
proposed EPA action or rulemaking
after publication in the Federal Regis-.
ter.
Commercial Waste Management Facil-
ity: A treatment, storage, disposal, or
transfer facility which accepts waste
from a variety of sources, as compared
to a private facility which normally
manages a limited waste stream gener-
ated by its own operations.
Commercial Waste: All solid waste
emanating from business establish-
ments such as stores, markets, office
buildings, restaurants, shopping cen-
ters, and theaters.
Commingled Recyclables: Mixed recyc-
lables that are collected together.
Comminuter: A machine that shreds or
pulverizes solids to make waste treat-
ment easier.
Comminution: Mechanical shredding or
pulverizing of waste. Used in both solid
waste management and wastewater
treatment.
Community: In ecology, a group of
interacting populations in time and
space. Sometimes, a particular sub-
grouping may be specified, such as the
fish community in a lake or the soil
arthropod community in a forest.
Community Relations: The EPA effort
to establish tworway communication
with the public to create under-
standing of EPA programs and related
actions, to assure public input into
decision-making processes related to
affected communities, and to make
certain that the Agency is aware of
and responsive to public concerns.
Specific community relations activities
are required in relation to Superfund
remedial actions.
Community Water System: A public
water system which serves at least 15
service connections used by year-round
residents or regularly serves at least
25 year-round residents.
Compaction: Reduction of the bulk of
solid waste by rolling and tamping.
Complete Treatment: A method of
treating water that consists of the
addition of coagulant chemicals, flash
mixing, coagulation-flocculation, sedi-
mentation, and filtration. Also called
conventional filtration.
Compliance Coal Any coal tht emits
less than 1.2 pounds of sulfur dioxide
per million Btu when burned. Also
known as low sulfur coal.
Compliance Coating: A coating whose
volatile organic compound content does
not exceed that allowed by regulation.
Compliance Cycle: The 9-year calendar
year cycle, beginning January 1,1993,
during which public water systems
must monitor. Each cycle consists of
three 3-year compliance periods.
Compliance Monitoring: Collection and
evaluation of data, including self-moni-
toring reports, and verification to show
whether pollutant concentrations and
loads contained in permitted discharg-
es are in compliance with the limits
and conditions specified in the permit.
Compliance Schedule: A negotiated
agreement between a pollution source
and a government agency that specifies
dates and procedures by which a
source will reduce emissions and,
thereby, comply with a regulation.
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9
Composite Sample: A series of water
samples taken over a given period of
time and weighted by flow rate.
Comport: The relatively stable humus
material that is produced from a comp-
osting process in which bacteria in soil
mixed with garbage and degradable
trash break down the mixture into or-
ganic fertilizer.
Composting: The controlled biological
decomposition of organic material in
the presence of air to form a humus-
like material. Controlled methods of
composting include mechanical mixing
and aerating, ventilating the materials
by dropping them through a vertical
series of aerated chambers, or placing
the compost in piles out in the open air
and mixing it or turning it periodically.
Compressed Natural Gaa (CNG): An
alternative fuel for motor vehicles;
considered one of the cleanest because
of low hydrocarbon emissions and its
vapors are relatively non-ozone produc-
ing. It does, however, emit a signifi-
cant quantity of nitrogen oxides.
Conditional Registration: Under special
circumstances, the Federal Insecticide,
Fungicide, and Rodenticide Act
(FIFRA) permits registration of pesti-
cide products that is "conditional" upon
the submission of additional data.
These special circumstances include-a
. finding by the EPA Administrator that
a new product or use of an existing
pesticide will not significantly increase
the risk of unreasonable adverse ef-
fects. A product-containing a new (pre-
viously unregistered) active ingredient
may be conditionally registered only if
the Administrator finds that such
conditional registration is in the public
interest, that a reasonable time for
conducting the additional studies has
not elapsed, and the use of the pesti-
cide for the period of conditional regis-
tration will not present an unreason-
able risk.
Conditionally Exempt Generators (CE):
Persons or enterprises which produce
less than 220 pounds of hazardous
waste per month. Exempt from most
regulation, they are required merely to
determine whether their waste is haz-
ardous, notify appropriate state or
local agencies, and ship it by permitted
facility for proper disposal. (See: small
quantity generator.)
Conductance: A rapid method of esti-
mating the dissolved solids content of
water supply by determining the ca-
pacity of a water sample to carry an
electrical current.
Conductivity: A measure of the ability
of a solution to carry and electrical
curerent.
Cone of Depression: A depression in
the water table that develops around a
pumped well.
Cone of
The depression,.
.
roughly conical in shape, produced in a
water table by the pumping of a well.
Confined Aquifer An aquifer in which
ground water is confined under pres-
sure which is significantly greater than
atmospheric pressure.
Confluent Growth: A continuous bacte-
rial growth covering all or part of the
filtration area of a membrane filter in
which the bacteria colonies are not
discrete.
Consent Decree: A legal document, ap-
proved by a judge, that formalizes an
agreement reached between EPA and
potentially responsible parties (PRPs)
through which PRPs will conduct all or
part of a cleanup action at a Superfund
site; cease or correct actions or pro-
cesses that are polluting the environ-
ment; or otherwise comply with EPA
initiated regulatory enforcement ac-
tions to resolve the contamination at
the Superfund site involved. The con-
sent decree describes the actions PRPs
will take and may be subject to a pub-
lic comment period.
Conservation: Preserving and renew-
ing, when possible, human and natural
resources. The use, protection, and
improvement of natural resources ac-
cording to principles that will assure
their highest economic or social bene-
fits.
Construction and Demolition Waste:
Waste building materials, dredging
materials, tree stumps, and rubble
resulting from construction, remodel-
ing, repair, and demolition of homes,
commercial buildings and other struc-
tures and pavements. May contain
lead, asbestos, or other hazardous sub-
stances.
Construction Ban: If, under the Clean
Air Act, EPA disapproves an area's
planning requirements for correcting
nonattainment, EPA can ban the con-
struction or modification of any major
stationery source of the pollutant for
which the area is in nonattainment.
Consumptive Water Use: Water re-
moved from available supplies without
return to a water resources system,
e.g., water used in manufacturing,
agriculture, and food preparation.
Contact Pesticide: A chemical that kills
pests when it touches them, instead of
by ingestion. Also, soil that contains
the minute skeletons of certain algae
that scratch and dehydrate waxy coat-
ed insects.
Contaminant: Any physical, chemical,
biological, or radiological substance or
matter that has an adverse affect on
air, water, or soil.
Contamination: Introduction into wa-
ter, air, and soil of microorganisms,
chemicals, toxic substances, wastes, or
waste water in a concentration that
makes the medium unfit for its next
intended use. Also applies to surfaces
of objects, buildings, and various
household and agricultural use prod-
ucts.
Contingency Plan: A document setting
out an organized, planned, and coordi-
nated course of action to be followed in
case of a fire, explosion, or other acci-
dent that releases toxic chemicals,
hazardous waste, or radioactive mate-
rials that threaten human health or
the environment. (See: National Oil
and Hazardous Substances Contingen-
cy Plan.)
Continuous Discharge: A routine re-
lease to the environment that occurs
without interruption, except for infre-
quent shutdowns for maintenance,
process changes, etc.
Continuous Sample: A flow of water
from a particular place in a plant to
the location where samples are col-
lected for testing. May be used to ob-
tain grab or composite samples.
Contour Plowing: Soil tilling method
that follows the shape of the land to
discourage erosion.
Contour Strip Farming: A kind of con-
tour farming in which row crops are
planted in strips, between alternating
stripls of close-growing, erosion-resis-
tant forage crops.
Contract Labs: Laboratories under
contract to EPA, which analyze sam-
ples taken from waste, soil, air, and
water or carry out research projects.
Control Technique Guidelines (CTG): A
series of EPA documents designed to
assist states in defining reasonable
available control technology (RACT) for
major sources of volatile organic com-
pounds (VOC).
Controlled Reaction: A chemical reac-
tion under temperature and pressure
conditions maintained within safe
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10
limits to produce a desired product or
process.
Conventional Filtration: (See: complete
treatment.)
Conventional Pollutants: Statutorily
listed pollutants understood well by
scientists. These may be in the form of
organic waste, sediment, acid, bacteria,
viruses, nutrients, oil and grease, or
heat.
Conventional Systems: Systems that
have been traditionally used to collect
municipal wastewater in gravity sew-
ers and convey it to a central primary
or secondary treatment plant prior to
discharge to surface waters.
Conventional Tilling: Tillage opera-
tions considered standard for a specific
location and crop and that tend to bury
the crop residues; usually considered
as a base for determining the cost
effectiveness of control practices.
Conveyance Loss: Water loss in pipes,
channels, conduits, ditches by leakage
or evaporation.
Cooling Electricity Use: Amount of
electricity used to meet the building
cooling load. (See: building cooling
load.)
Cooling Tower A structure that helps
remove heat from water used as a cool-
ant; e.g., in electric power generating
plants.
Cooperative Agreement: An assistance
agreement whereby EPA transfers
money, property, services or anything
of value to a state for the accomplish-
ment of CERCLA-authorized activities
or tasks.
Core: The uranium-containing heart of
a nuclear reactor, where energy is re-
leased. ;
Core Program Cooperative Agreement:
An assistance agreement whereby EPA
supports states or tribal governments
with funds to help defray the cost of
non-item-specific administrative and
training activities.
Corrosion: The dissolution and wearing
away of metal caused by a rhamirjl
reaction such as between water and
the pipes, chemicals touching a metal
surface, or contact between two metals.
Corrosive: A chemical agent that reacts
with the surface of a material causing
it to deteriorate or wear away.
CoaVBenefit Analysis: A quantitative
evaluation of the costs which would be
incurred by implementing an environ-
mental regulation versus the overall
benefits to society of the proposed action.
Cost-Effective Alternative: An alterna-
tive control or corrective method iden-
tified after analysis as being the best
available in terms of reliability, perfor-
mance, and cost. Although costs are
one important consideration, regulat-
ory and compliance analysis does not
require EPA to choose the least expen-
sive alternative. For example, when
selecting or approving a method for
cleaning up a Superfund site the Agen-
cy balances costs with the long-term
effectiveness of the methods proposed
and the potenetial danger posed by the
site.
Cost Recovery: A legal process by
which potentially responsible parties
who contributed to contamination at a
Superfund site can be required to re-
imburse the Trust Fund for money
spent during any cleanup actions by
the federal government.
Cost Sharing: A publicly financed pro-
gram through which society, as a bene-
ficiary of environmental protection,
shares part of the cost of pollution
control with those who must actually
install the controls. In Superfund, for
example, the government may pay part
of the cost.of a cleanup action with
those responsible for the pollution
paying the major share.
Cover Crop: A crop that provides tem-
porary protection for delicate seedlings
and/or provides a cover canopy for
seasonal soil protection and improve-
ment between normal crop production
periods.
Cover Material: Soil used to cover com-
pacted solid waste in a sanitary land-
fill. .
Cradle-to-Grave or Manifest System: A
procedure in which hazardous materi-
als are identified and followed as they
are produced, treated, transported, and
disposed of by a series of permanent,
linkable, descriptive documents (e.g.,
manifests). Commonly referred to as
the cradle-to-grave system.
Criteria Pollutants: The 1970 amend-
ments to the Clean Air Act required
EPA to set National Ambient Air Qual-
ity Standards for certain pollutants
known to be hazardous to human
health. EPA has identified and set
standards to protect human health and
welfare for six pollutants: ozone, car-
bon monoxide, total suspended particu-
lates, sulfur dioxide, lead, and nitrogen
oxide. The term, "criteria pollutants"
derives from the requirement that EPA
must describe the characteristics and
potential health and welfare effects of
these pollutants. It is on the basis of
these criteria that standards are set or
revised.
Criteria: Descriptive factors taken into
account by EPA in setting standards
for various pollutants. These factors
are used to determine limits on allow-
able concentration levels, and to limit
the number of violations per year.
When issued by EPA, the criteria pro-
vide guidance to the states on how to
establish their standards.
Crop Consumptive Use: The amount of
water transpired during plant growth
plus what evaporated from the soil
surface and foliage in the crop area.
Crop Rotation: Planting a succession of
different crops on the same land rea as
opposed to planting the same crop time
after time.
Cross-Connection: Any actual or poten-
tial connection between a drinking
water systemm and an unapproved
water supply or other source of con-'
tamination.
Cubic Feet Per Minute (CFM): A mea-
sure of the volume of a substance flow-
ing through air within a fixed period of
time. With regard to indoor air, refers
to the amount of air, in cubic feet, that
is exchanged with indoor air in a
minute's time, i.e., the air exchange
rate. Also applies to liquid flows.
Gullet: Crushed glass.
Cultural Eutropbication: Increasing
rate at which water bodies "die" by pol-
lution from human activities.
Cultures and Stocks: Infectious agents
and associated biologicals including:
cultures from medical and pathological
laboratories; cultures and stocks of
infectious agents from research and
industrial laboratories; waste from the
production of biologicals; discarded live
and attenuated vaccines; and culture
dishes and devices used to transfer, in-
'oculate, and mix cultures. (See: regu-
lated medical waste.)
Cumulative Exposure: The sum of
exposures of an organism to a pollut-
ant over a period of time.
Cumulative Working Level Months
(CWLM): The sum of lifetime exposure
to radon working levels expressed in
total working level months.
Curb Stop: A water service shutoff
valve located in a water service pipe
near the curb and between the water
main and the building.
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11
Curbside Collection: Method of collect-
ing recyclable materials at homes,
community districts or businesses.
Cutie-Pie: An instrument used to mea-
sure radiation levels.
Cyclone Collector. A device that uses
centrifugal force to pull large particles
from polluted air.
Data Call-In; A part of the Office of
Pesticide Programs (OPP) process of
developing key required test data,
especially on the long-term, chronic
effects of ««riiiting pesticides, in ad-
vance of scheduled Registration Stan-
dard reviews. Data Call-In from man-
ufacturers is an adjunct of the Regis-
tration Standards program intended to
expedite re-registration.
Day Tank: (See: age tank)
DDT: The first chlorinated
hydrocarboninsecticide r^Amiral name:
Dichloro-Diphenyl-Trichloroethane). It
has a half-life of 15 years and can col-
lect in fatty tissues of certain animals.
EPA banned registration and inter-
state sale of DDT for virtually, all but
emergency uses in the United States in
1972 because of its persistence in the
environment and accumulation in the
food chain.
Dead End: The end of a water main
which is not connected to other parts of
the distribution system.
Decant: To draw off the upper layer of
liquid after the heaviet material (a
solid or another liquid) has settled.
Decay Products: Degraded radioactive
materials, often referred to as "daugh-
ters" or "progeny"; radon decay prod-
ucts of most concern from a public
health standpoint are polonium-214
and polonium-218.
Dechlorination: Removal of chlorine
from a substance by chemically replac-
ing it with hydrogen or hydroxide ions
in order to detoxify a substances.
Decomposition: The breakdown of
matter by bacteria and fungi, changing
the chemical makeup and physical ap-
pearance of materials.
Decontamination: Removal of harmful
substances such as noxious I'hftTnirala,
.harmful bacteria or other organisms,
or radioactive material from exposed
individuals, rooms and furnishings in
buildings, or the exterior environment.
Deep-Well Injection: Deposition of raw
or treated, filtered hazardous waste by
pumping it into deep wells, where it is
contained in the pores of permeable
subsurface rock.
Deflocculating Agent A material added
to a suspension to prevent settling.
Defhioridation: The removal of excess
Qouride in drinking water to prevent
the staining of teeth.
Defoliant: An herbicide that removes
leaves from trees and growing- plants.
Degaaification: A water treatment
that removes dissolved gases from
the water.
Delegated State: A state (or other
governmental entity such as a tribal
government) that has received authori-
ty to administer an environmental
regulatory program in lieu of a federal
counterpart As used in connection
with NPDES, UIC, and PWS pro-
grams, the term does not connote any
transfer of federal authority to a state.
Delist Use of the petition process to
have a facility's toxic designation re-
scinded.
Demand-aide Waste Management:
Prices whereby consumers use pur-
chasing decisions to communicate to
product manufacturers that they prefer
environmentally sound products pack-
aged with the least amount of waste,
made from recycled or recyclable mate-
rials, »T»ti containing no hazardous
substances.
rwrmfn«»r«ii«ntinTv A treatment process
that removes dissolved minerals from
water.
Denitrification: The anaerobic biolog-
ical reduction of nitrate to nitrogen
gas.
Density: A measure of how heavy a
solid, liquid, or gas is for its size.
Depletion Curve: In hydraulics, a
graphical representation of water de-
pletion from storage-stream channels,
surface soil, and groundwater. A deple-
tion curve can be drawn for base flow,
direct runoff, or total flow.
Depressurization: A condition that
occurs when the air pressure inside a
structure is lower that the air pressure
outside. Depressurization can occur
when household appliances such as
fireplaces or furnaces, that consume or
exhaust house air, are not supplied
with enough makeup air. Radon may
be drawn into a house more rapidly
under depressurized conditions.
Dermal Exposure: Contact between a
chemical and the akin.
Dermal Toxicity: The ability of a pesti-
cide or toxic chemical to poison people
or animals by contact with the skin.
(See: contact pesticide.)
DBS: A synthetic estrogen, diethylstil-
bestrol is used as a growth stimulant
in food animals. Residues in meat are
thought to be carcinogenic.
Desalination: [Desalinization] (1) Re-
moving salts from ocean or brackish
water by using various technologies.
(2) Removal of salts from soil by artifi-
cial means, usually leaching.
Deaiccant A chemical agent that ab-
sorbs moisture; some desiccants are
capable of drying out plants or insects,
causing death.
Design Capacity: The average daily
flow that a treatment plant or other
facility is designed to accommodate.
Design Value: The monitored reading
used by EPA to determine an area's air
quality status, e.g., for ozone, the
fourth highest reading measured over
the most recent three years is the
design value.
Designated Pollutant An air pollutant
which is neither a criteria nor hazard-
ous pollutant, as described in the
Clean Air Act, but for which new
source performance standards exist.
The Clean Air Act does require states
to control these pollutants, which in-
clude acid mist, total reduced sulfur
(TRS), and fluorides.
Designated Uses: Those water uses
identified in state water quality stan-
dards that must be achieved and main-
tained as required under the Clean
Water Act Uses can include cold water
fisheries, public water supply, irriga-
tion, etc.
Designer Bugs: Popular term for mi-
crobes developed through biotechnology
that can degrade specific toxic chemi-
cals at their source in toxic waste
dumps or in ground water.
Destination Facility: The facility to
which regulated medical waste is
shipped for treatment and destruction,
incineration, and/or disposal.
WaiLi iitjr^^jnm- Vertical mnring within
a lake or reservoir to totally or partial-
ly eliminate separate layers of temper-
ature, plant, or animal life.
Destroyed Medical Waste: Regulated
medical waste that has been ruined,
torn apart, or mutilated through ther-
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12
mal treatment, melting, shredding,
grinding, tearing, or breaking, so that
it is no longer generally recognized as
medical waste, but has not yet been
treated (excludes compacted regulated
medical waste.)
Destruction and Removal Efficiency
(DRE): A percentage that represents
the number of molecules of a com-
pound removed or destroyed in an
incinerator relative to the number of
molecules that entered the • system
(e.g., a DRE of 99.99 percent means
that 9,999 molecules are destroyed for
every 10,000 that enter; 99.99 percent
is known as "four nines." For some
pollutants, the RCRA removal require-
ment may be a stringent as "six
nines.")
Destruction Facility: A facility that de-
stroys regulated medical waste by
mashing or mutilating it.
Detention Time: 1. The theoretical cal-
culated time required for a small
amount of water to pass through a
tank at a given rate of flow. 2. The
actual time that a small amount of
water is in a settling basin, flocculat-
ing basin, or rapid-mix chamber. 3. In
storage reservoirs, the length of time
water will be held before being used.
Desulfurization: Removal of sulfur
from fossil fuels to reduce pollution.
Detectable Leak Rate: The smallest
leak (from a storage tank), expressed
in terms of gallons-or liters-per-hour,
that a test can reliably discern with a
certain probability of detection or false
alarm.
Detection Criterion: A predetermined
rule to ascertain whether a tank ia
leaking or not. Most volumetric testa
use a threshold value as the detection
criterion. (See: volumetric tank testa.)
Detergent: Synthetic washing agent
that helps to remove dirt and oil. Some
contain compounds which kill useful
bacteria and encourage algae growth
when they are in wastewater that
reaches receiving waters.
Development Efifecta: Adverse effects
such as altered growth, structural
abnormality, functional deficiency, or
death observed in a developing organ-
ism.
Dewater 1. Remove or separate a
portion of the water in a sludge or
slurry to dry the sludge so it «•-«" be
handled and disposed. 2. Remove
or drain the water from a tank or
trench.
Diatomaceoua Earth (Diatomite): A
chalk-like material (fossilized diatoms)
used to filter out -solid waste in
wastewater treatment plants; also used
as an active ingredient in some pow-
dered pesticides.
Diazinon: An insecticide. In 1986, EPA
banned its use on open areas such as
sod farms and golf courses because it
posed a danger to migratory birds. The
ban did not apply to agricultural,
home lawn, or commercial establish-
ment uses.
\
Dibenzofurans: A group of highly toxic
organic compounds.
Dicofol: A pesticide used on citrus
fruits.
Diffused Air A type of aeration that
forces oxygen into sewage by pumping
air through perforated pipes inside a
holding tank.
Diffusion: The movement of suspended
or dissolved particles from a more con-
centrated to a less concentrated area.
The process tends to distribute the
particles more uniformly.
Digester In wastewater treatment, a
closed tank; in solid-waste conversion,
a unit in which bacterial action is in-
duced and accelerated in order to
break down organic matter and estab-
lish the proper carbon to nitrogen
ratio.
Digestion: The biochemical decomposi-
tion of organic matter, resulting in
partial gasification, liquefaction, and
mineralization of pollutants.
Dike: A low wall that can act as a
barrier to prevent a spill from spread-
ing.
Diluent: Any liquid or solid material
used to dilute or carry an active ingre-
dient
Dilution Ratio: The relationship be-
tween the volume of water in a stream
and the volume of incoming water. It
affects the ability of the stream to
assimilate waste.
Dimitie Lakes and reservoirs that
freeze over and normally go through
two stratifications and two mixing
cycles a year.
Dinocap: A fungicide used primarily by
apple growers to control summer dis-
eases. EPA proposed restrictions on its
use in 1986 when laboratory tests
found it caused birth defects in rabbits.
Dinoeeb: A herbicide that is also used
as a fungicide and insecticide. It was
banned by EPA in 1986 because it
posed the risk of birth defects and
sterility.
Dioxin: Any of a family of compounds
known chemically as dibenzo-p-dioxins.
Concern about them arises from their
potential toxicity and contaminants in
commercial products. Tests on labora-
tory animals indicate that it is one of
the more toxic man-made compounds.
Direct Discharger A municipal or
industrial facility which introduces
pollution through a defined conveyance
or system such as outlet pipes; a point
source.
Direct Filtration: A method of treating
water which consists of the addition of
coagulent chemicals, flash mixing,
coagulation, minimal flocculation, and
filtration. Sedimentation is not used!
Direct Runoff: Water that flows over
the ground surface or through the
ground directly into streams, rivers,
and lakes.
Discharge: Flow of surface water-in a
stream or canal or the outflow of
ground water from a flowing artisian
well, ditch, or spring. Can also apply to
discharge of liquid effluent from a
facility or to chemical emissions into
the air through designated venting
mechanisms.
Din
mfc A chemical or physical
process that kills pathogenic organisms
in water. Chlorine is often used to
disinfect sewage treatment effluent,
water supplies, wells, and swimming
pools.
Disinfectant By-Producfc A compound
formed by the reaction of a
disinfenctant such as chlorine with or-
ganic material in the water supply.
Disinfectant Time: The time it takes
water to move from the point of disin-
fectant application (or the previous
point of residual disinfectant measure-
ment) to a point before or at the point
where the residual disinfectant is mea-
sured.
Dispersant: A chemical agent used to
break up concentrations of organic
material such as spilled oil.
Disposables: Consumer products, other
items, and packaging used once or a
few times and discarded.
Disposal: Final placement or destruc-
tion of toxic, radioactive, or other
wastes; surplus or banned pesticides or
other chemicals; polluted soils; and
drums containing hazardous materials
from removal actions or accidental
releases. Disposal may be accom-
plished through use of approved secure
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13
landfills, surface impoundments, land
farming, deep-well injection, ocean du-
mping, or incineration.
Dissolved Oxygen (DO): The oxygen
freely available in water, vital to fish
and other aquatic life and for the pre-
vention of odors. DO levels are consid-
ered a most important indicator of a
water body's ability to support desir-
able aquatic life. Secondary and ad-
vanced waste treatment are generally
designed to ensure adequate DO in
waste-receiving waters.
Dissolved Solids: Disintegrated organic
and inorganic material in water. Ex-
cessive amounts make water unfit to
drink or use in industrial processes.
Distillation: The act of purifying li-
quids through boiling, so that the
steam condenses to a pure liquid and
the pollutants remain in a concentrat-
ed residue.
Diversion: 1. Use of part of a stream
flow as water supply. 2. A channel
with a supporting ridge on the lower
side constructed across a slope to di-
vert waster at a non-erosive velocity to
sites where ait can be used, and dis-
posed of.
Diversion Rate: The percentage of
waste materials diverted from tradi-
tional disposal such as landfilling or
incineration to be recycled, composted,
or re-used.
DNA Hybridization: Use of a segment
of DNA, called a DNA probe, to identi-
fy its complementary DNA; used to
detect specific genes.
Dosage/Dose: The actual quantity of a
chemical administered to an organism
or to which it is exposed.
Doee Equivalent: The product of the
absorbed dose from ionizing radiation
and such factors as account for biologi-
cal differences due to the type of radia-
tion and its distribution in the body as
specified by the International Commis-
sion on Radiological Units and Mea-
surements.
Dose Response: How a biological orga-
nism's response to a toxic substance
quantitatively shifts as its overall
exposure to the substance: changes
(e.g., a small dose of carbon monoxide
may cause drowsiness; a large dose can
be fatal.)
Dose-Response Assessment Estimating
the potency of a chemical.
Dose-Response Relationship: The quan-
titative relationship between the
amount of exposure to a substance and
the extent of toxic injury or disease
produced.
DOT Reportable Quantity: The quanti-
ty of a substance specified in U.S. De-
partment of Transportation regulation
that triggers labelling, packaging and
other requirements related to shipping
such substances.
Downgradient The diretion that
groundwater flows; similar to "down-
stream" for surface water.
Draft 1. The act of drawing or remov-
ing water from a tank or reservoir. 2.
The water which is drawn or removed.
Draft Permit: A preliminary permit
drafted and published by EPA; subject
to public review and comment before
final action on the application.
Drainage: Improving the productivity
of agricultural land by removing excess
water from the soil by such means as
ditches or subsurface drainage tiles.
Drainage Basin: The area of land that
drains water, sediment, and dissolved
materials to a common outlet at some
point along a stream channel.
Drainage Well: A well drilled to carry
excess water off agricultural fieleds.
Because they act as a funnel from the
surface to the groundwater below,
drainage wells can contribute to
groundwater pollution.
Drawdown: 1. The drop in the water
table or level of water in the ground
when water is being pumped from a
well. 2. The amount of water used from
a tank or reservoir. 3. The drop in the
water level of a tank or reservoir.
Dredging: Removal of mud from the
bottom of water bodies. This can dis-
turb the ecosystem and cause silting
that kills aquatic life. Dredging of
contaminated muds can expose biota to
heavy metals and other toxics. Dredg-
ing activities may be subject to regula-
tion under Section 404 of the Clean
Water Act
Drinking Water Equivalent Level:
Protective level of exposure related to
potentially non-carcinogenc effects of
chemicals that are also known to cause
cancer.
Drop-off: Recyclable materials collec-
tion method in which individuals bring
them to a designated collection site.
Dump: A site used to dispose of solid
waste without environmental controls.
Dustfall Jar: An open container used to
collect large particles from the air for
measurement and analysis.
Dystrophic Lakes: Acidic, shallow bod-
ies of water that contain much humus
and/or other organic matter; contain
many plants but few fish.
Ecological Impact The effect that a
man-made or natural activity has on
living organisms and their non-living
(abiotic) environment.
Ecology: The relationship of living
things to one another and their envi-
ronment, or the study of such relation-
ships.
Ecological Indicator A characteristic
of the environment that, when mea-
sured, quantifies magnitude of stress,
habitat characteristics, degree of expo-
sure to a stressor, or ecological re-
sponse to exposure. The term is a
collective term for response, exposure,
habitat, and stressor indicators.
Ecological Risk Assessment The ap-
plication of a formal framework, ana-
lytical process, or model to estimate
the effects of human actions(s) on a
natural resource and to interpret the
significance of those effects in light of
the uncertainties identified in each
component of the assessment process.
Such analysis includes initial hazard
identification, exposure and dose-re-
sponse assessments, and risk char-
acterization.
Rfmnnmic Poisons: Chemicals used to
control pests and to defoliate cash
crops such as cotton.
Ecosphere: The "bio-bubble" that con-
tains life on earth, in surface waters,
and in the air. (See: biosphere.)
Ecosystem: The interacting system of a
biological community and its non-living
environmental surroundings.
Ecosystem Structure: Attributes relat-
ed to instantaneous physical state of
an ecosystem; examples include species
population density, species richness or
evenness, and standing crop biomass.
\
Ecotone: A habitat created by the jux-
taposition of distinctly different habi-
tats; an edge habitat; or an ecological
zone or boundary where two or more
ecosystems meet.
Effluent Wastewater, treated or
untreated that flows out of a treatment
plant, sewer, or industrial outfall.
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14
Generally refers to wastes discharged
into surface waters.
Effluent Guidelines: Technical EPA
documents which set effluent limita-
tions for given industries and pollut-
ants.
Effluent Limitation: Restrictions estab-
lished by a state or EPA on quantities,
rates, and concentrations- in
wastewater discharges.
Effluent Standard: (See: effluent limi-
tation.)
Ejector A device used to disperse a
chemical solution into water being
treated. •
Electrodialyais: A process that uses
electrical current applied to permeable
membranes to remove minerals from
water. Often used to desalinate salty
or brackish water.
Electrostatic Precipitator (ESP): A
device that removes particles from a
gas stream (smoke) after combustion
occurs. The ESP imparts an electrical
charge to the particles, causing them
to adhere to metal plates inside the
precipitator. Rapping on the plates
causes the particles to fall into a hop-
per for disposal.
Eligible Costa: The construction costs
' for waste-water treatment works upon
which EPA grants are based.
EMAP Data: 'Environmental monitor-
ing data collected under the auspices of
the Environmental Monitoring, and
Assessment Program. All EMAP data
share the common attribute of being of
known quality, having been collected
in the context of explicit data quality
objectives (DQOs) and a consistent
quality assurance program.
Emergency (Chemical): A situation
created by an accidental release or
spill of hazardous chemicals that poses
a threat to the safety of workers, resi-
dents, the environment, or property.
Emergency Episode: (See: air pollution
episode.)
Emergency Response Values: Concen-
trations of chemicals, published, by
various groups, defining acceptable
levels for short-term exposures in
emergencies.
Emission: Pollution discharged into the
atmosphere from smokestacks, other
vents, and surface areas of commercial
or industrial facilities; from residential
chimneys; and from motor vehicle, loco-
motive, or aircraft exhausts.
Emission Cap: A limit designed to
prevent projected growth in emissions
from existing and future stationary
sources from eroding any mandated re-
ductions. Generally, such provisions
require any emission growth from
facilities under the restrictions be
offset by equivalent reductions at other
facilities under the saine cap. (See:
emissions trading)
Emission Factor The relationship
between the amount of pollution pro-
duced and the amount of raw material
processed. For example, an emission
factor for a blast furnace making iron
would be the number of pounds of
particulates per ton of raw materials.
Emission Inventory: A listing, by
source, of the amount of air pollutants
discharged into the atmosphere of a
community; used to establish emission
standards.
Emission Standard: The maximum
amount of air polluting discharge le-
gally allowed from a single source,
mobile or stationary.
Emissions Trading: The creation of
surplus emission reductions at certain
stacks, vents or similar emissions
sources and the use of this surplus to
meet or redefine pollution require-
ments applicable to other emissions
sources. This allows one source to
increase emissions when another
source reduces them, maintaining an
overall constant emission level. Facili-
ties that reduce emissions substantial-
ly may "bank" their "credits" or sell
them to other facilities or industries.
Encapsulation: The treatment of asbes-
tos-containing material with a liquid
that covers the surface with a protec-
tive coating or embeds fibers in an
adhesive matrix to prevent their re-
lease into the air.
Enclosure: Putting an airtight, imper-
meable, permanent barrier around as-
bestos-containing materials to prevent
the release of asbestos fibers into the
air.
Endangered Species: Animals, birds,
fish, plants, or other living organisms
threatened with extinction by man-
made or natural changes in their envi-
ronment. Requirements for declaring a
species endangered are contained in
the Endangered Species Act.
Endangerment Assessment: A study to
determine the nature and extent of
contamination at a site on the National
Priorities Last and the risks posed to
public health or the environment. EPA
or the state conduct the study when a
legal action is to be taken to direct
potentially responsible parties to clean
up a site or pay for it. An endanger-
ment assessment supplements a reme-
dial investigation.
Endrin: A pesticide toxic to freshwater
and marine aquatic life that produces
adverse health effects in domestic
water supplies..
Energy Recovery: Obtaining energy
from waste through a variety of pro-
cesses (e.g., combustion.)
Enforceable Requirements: Conditions
or limitations in permits issued under
the Clean Water Act .Section 402 or
404 that, if violated, could result in
the issuance of a compliance order or
initiation of a civil or criminal action
under federal or applicable state laws.
If a permit has not been issued, the
term includes any requirement which,
in the Regional Administrator's judg-
ement, would be included in the permit
when issued. Where no permit applies,
the term includes any requirement
which the RA determines is necessary
for the best practical waste treatment
technology to meet applicable criteria.
Enforcement: EPA, state, or local legal
actions to obtain compliance with envi-
ronmental laws, rules, regulations, or
agreements and/or obtain penalties or
criminal sanctions for violations. En-
forcement procedures may vary, de-
pending on the requirements of differ-
ent environmental laws and related
implementing regulations. Under
CERCLA, for example, EPA will seek
to require potentially responsible par-
ties to clean up a Superfund site, or
pay for the cleanup, whereas under the
Clean Air Act the agency may invoke
sanctions against cities failing to meet
ambient air quality standards that
could prevent certain types of construc-
tion or federal funding. In other situa-
tions, if investigations by EPA and
state agencies uncover willful viola-
tions, criminal trials and penalties are
sought.
Enforcement Decision Document
(EDD): A document that provides an
explanation to the public of EPA's se-
lection of the cleanup alternative at
enforcement sites on the National
Priorities List. Similar to a Record of
Decision.
Enhanced Inspection and Maintenance
(I&M): An improved automobile inspec-
tion and maintenance program—aimed
at reducing automobile emissions—that
contains, at a minimum, more vehicle
types and model years, tighter inspec-
tion, and better management practices.
It may also include annual computer-
ized or centralized inspections, under-
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15
the-hood inspection- for signs of tam-
pering with pollution control equip-
ment, and increased repair waiver cost.
Enrichment: The addition of nutrients
(e.g., nitrogen, phosphorus, carbon
compounds) from sewage effluent or
agricultural runoff to surface water;
greatly increases the growth potential
for algae and other aquatic plants.
Entrain: To trap bubbles in water
either mechanically through turbu-
lence or chemically through a reaction.
Environment: The sum of all external
conditions affecting the life, develop-
ment and survival of an organism.
Environmental Assessment: An envi-
ronmental analysis prepared pursuant
to the National Environmental Policy
Act to determine whether a federal
action would significantly affect the
environment and thus require a more
detailed environmental impact state-
ment.
Environmental Audit: An independent
assessment of the current status of a
party's compliance with applicable
environmental requirements or of a
party's environmental compliance poli-
cies, practices, and controls.
Environmental Equity/Justice: Equal
protection from environmental hazards
for individuals, groups, or communities
regardless of race, ethnicity, or eco-
nomic status. This applies to the de-
velopment, implementation, and en-
forcement of environmental laws, regu-
lations, and policies, and implies that
no population of "people should be
forced to shoulder a disproportionate
share of negative environmental im-
pacts.
Environmental Exposure: Human
exposure to pollutants originating from
facility emissions. Threshold levels are
not necessarily surpassed, but low-
level chronic pollutant exposure is one
of the most common forma of environ-
mental exposure (See: threshold level).
Environmental Impact Statement: A
document required of federal agencies
by the National Environmental Policy
Act for major projects or legislative
proposals significantly affecting the en-
vironment. A tool for decision making,
it describes the positive and negative
effects of the undertaking and cites
alternative actions.
Environmental Indicator: A measure-
ment, statistic or value that provides a
proximate gauge or evidence of the
effects of environmental management
programs or of the state or condition of
the environment.
Environmental Response Team: EPA
experts located in Edison, NJ, and
Cincinnati, OH, who can provide
around-the-clock technical assistance
to EPA regional offices and states
during all types of hazardous waste
site emergencies and spills of hazard-
ous substances.
Epidemiology: Study of the distribution
of disease, or other health-related
states and events in human popula-
tions, as related to age, sex, occupa-
tion, ethnic, and economic status in
order to identify and alleviate health
problems and promote better health.
Epilimnion: Upper waters of a therm-
ally stratified lake subject to wind
action.
Episode (Pollution): An air pollution
incident in a given area caused by a
concentration of atmospheric pollut-
ants under meteorological conditions
that may result in a significant in-
crease in illnesses or deaths. May also
describe water pollution events or
hazardous material spills.
Equilibrium: In relation to radiation,
the state at which the radioactivity of
consecutive elements within a radioac-
tive series is neither increasing nor
decreasing.
Equivalent Method: Any method of
sampling and analyzing for air pollu-
tion which has been demonstrated to
the EPA Administrator's satisfaction to
be, under specific conditions, an ac-
ceptable alternative to normally used
reference methods.
Erosion: The wearing away of land
surface by wind or water, intensified
by land-clearing practices related to
farming, residential, or industrial de-
velopment, road building, or logging.
Estuary: Regions of interaction be-
tween rivers and near-shore ocean wa-
ters, where tidal action and river flow
mi-r fresh and salt water. Such areas
include bays, mouths of rivers, salt
marshes, and lagoons. These brackish
water ecosystems shelter and feed ma-
rine life, birds, and wildlife. (See:
wetlands.)
Ethanol: An altemativce automotive
fuel derived from grain and corn; usu-
ally blended with gasoline to form
gasohol.
Ethylene Dibromide (EDB): A chemical
used as an agricultural fumigant and
in certain industrial processes. Ex-
tremely toxic and found to be a car-
cinogen in laboratory animals, EDB
has been banned for most agricultural
uses in the United States.
Eutrophic Lakes: Shallow, murky bod-
ies of water with concentrations of
plant nutrients causing excessive pro-
duction of algae. (See: dystrophic
lakes.)
Eutrophication: The slow aging process
during which a lake, estuary, or bay
evolves into a bog or marsh and even-
tually disappears. During the later
stages of eutrophication the water body
is choked by abundant plant life due to
higher levels of nutritive compounds
such as nitrogen and phosphorus.
Human activities can accelerate the
process.
Evaporation Ponds: Areas where sew-
age sludge is dumped and dried.
Evapotranapiration: The loss of water
from the soil both by evaporation and
by transpiration from the plants grow-
ing in the soil.
Exceedance: Violation of the pollutant
levels permitted by environmental pro-
tection standards.
Exclusion: In the asbestos program,
one of several situations that permit a
Local Education Agency (LEA) to de-
lete one or more of the items required
by the Asbestos Hazard Emergency
Response Act (AHERA), e.g., records of
previous asbestos sample collection
and analysis may be used by the ac-
credited inspector in lieu of AHERA
bulk sampling.
Exclusionary Ordinance: Zoning that
excludes classes of persons or busi-
nesses from a particular neighborhood
or area.
Exempt Solvent: Specific organic com-
pounds not subject to requirements of
regulation because they are deemed by
EPA to be of negligible photochemical
reactivity.
Exempted Aquifer: Underground bod-
ies of water defined in the Under-
ground Injection Control program as
aquifers that are potential sources of
drinking water though not being used
as such, and thus exempted from regu-
lations barring underground injection
activities.
Exemption: A state (with primacy) may
exempt a public water system from-a
requirement involving an MCL, treat-
ment technique; or both, if the. system
cannot comply due to compelling eco-
nomic or other factors, or because the
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16
system was in operation before the
requirement or MCL was instituted,
and the exemption will not create a
public health risk.
Exotic Species: A species that is not
indigenous to a region.
Experimental Use Permit: Obtained by
manufacturers for testing new pesti-
cides or uses of thereof whenever they
conduct experimental field studies to
support registration on 10 acres or
more on land or one acre or more of
water.
Explosive Limits: The amounts of va-
por in the air that form explosive mix-
tures; limits are expressed as lower
and upper limits and give the range of
vapor concentrations in air that \vill
explode if an ignition source is present.
Exposure: The amount of radiation or
pollutant present in a given environ-
ment that represents a potential
health threat to living organisms.
Exposure Assessment: Identifying the
pathways by which toxicants may
reach individuals, estimating how
much of a chemical an individual is
likely to be exposed to, and estimating
the number likely to be exposed.
Exposure Indicator A characteristic of
the environment measured to provide
evidence of the occurrence or magni-
tude of a response indicator's exposure
to a chemical or biological stress.
Exposure Level: The amount (concen-
tration) of a chemical at the absorptive
surfaces of an organism.
Extraction Procedure (E P Toxic): De-
termining toxicity by a procedure
which simulates leaching; if a certain
concentration of a toxic substance can
be leached from a waste, that waste is
considered hazardous, i.e., "E P Toxic."
Extremely Hazardous Substances:
Any of 406 chemicals identified by EPA
as toxic, and listed under SARA Title
III. The list is subject to periodic revi-
sion.
Fabric Filter: A cloth device that catch-
es dust particles from industrial emis-
sions.
Facilities Plans: Plans and studies
related to the construction of treat-
ment works necessary to comply with
the Clean Water Act or RCRA. A facili-
ties plan investigates needs and pro-
vides information on the cost effective-
ness of alternatives, a recommended
plan, an environmental assessment of
the recommendations, and descriptions
of the treatment works, costs, and a
completion schedule.
Facility Emergency Coordinator Rep-
resentative of a facility covered by
environmental law (e.g, a chemical
plant) who participates in the emer-
gency reporting process with the Local
Emergency Planning Committee
(LEPC).
Facultative Bacteria: Bacteria that can
live under aerobic or anaerobic condit-
ions.
Feasibility Study: 1. Analysis of the
practicability of a proposal; e.g., a de-
scription and analysis of potential
cleanup alternatives for a site such as
one on the National Priorities List. The
feasibility study usually recommends
selection of a cost-effective alternative.
It usually starts as soon as the remedi-
al investigation is underway; together,
they are commonly referred to as the
"RVFS". 2. A small-scale investigation
of a problem to ascertain whether a
proposed research approach is likely to
provide useful data.
Fecal Coliform Bacteria: Bacteria
found in the intestinal tracts of mam-
mals. Their presence in water or
sludge is an indicator of pollution and
possible contamination by pathogens.
Federal Implementation Plan: Under
current law, a federally implemented
plan to achieve attainment of air quali-
ty standards, used when a state is
unable to develop an adequate plan.
Federal Motor Vehicle Control Pro-
gram; All federal actions aimed at
controlling pollution from motor vehi-
cles by such efforts as establishing and
enforcing tailpipe and evaporative
emission standards for new vehicles,
testing methods development, and
guidance to states operating inspection
and maintenance programs.
Feedlot A confined area for the con-
trolled feeding of animals. Tends to
concentrate large amounts of animal
waste that cannot be absorbed by the
soil and, hence, may be carried to
nearby streams or lakes by rainfall
runoff.
Fen: A type of wetland that accumu-
lates peat deposits. Fens are less acidic
than bogs, deriving most of their water
from groundwater rich in calcium and
magnesium. (See: wetlands.)
FIFRA Pesticide Ingredient: An ingre-
dient of a pesticide that must be regis-
tered with EPA under the Federal
Insecticide, fungicide, and Rodenticide
Act. Products making pesticide claims
must register under FIFRA and may
be subject to labeling and use require-
ments.
Filling: Depositing dirt, mud or other
materials into aquatic areas to create
more dry land, usually for agricultural
or commercial development purposes,
often with ruinous ecological conse-
quences.
Filter Strip: Strip or area of vegetation
used for removing sediment, organic
matter, and other pollutants from
runoff and waste water.
Filtration: A'treatment process, under
the control of qualified operators, for
removing solid (particulate) matter
from water by means of porous media
such as sand or a man-made filter;
often used to remove particles that
containing pathogens.
Financial Assurance for Closure: Docu-
mentation or proof that an owner or
operator of a facility such as a landfill
or other waste repository is capable of
paying the projected costs of closing
the facility and monitoring it after-
wards as provided in RCRA regula-
tions.
Finding of No Significant Impact- A
document prepared by a federal agency
showing why a proposed action would
not have a significant impact on the
environment and thus would not re-
quire preparation of an Environmental
Impact Statement. An FNSI is based
on the results of an environmental
assessment.
Finished Water Water that has passed
through all the processes in a water
treatment plant and is ready to be
delivered to consumers.
First Draw: The water that comes out
when a tap is first opened, likely to
have the highest level of lead contam-
ination from plumbing materials.
Fix a Sample: A sample is "fixed" in
the field by adding chemicals that
prevent water quality indicators of
interest in the sample from changing
before laboratory measurements are
made.
Flare: A control device that burns
hazardous materials to prevent their
release into the environment; may
operate continuously or intermittently,
usually on top a stack.
Floe A clump of solids formed in sew-
age by biological or chemical action.
Flocculation: Process by which clumps
of solids in water or sewage aggregate
through biological or chemical action so
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17
they can be separated from water or
sewage.
Floodplain: The flat or nearly flat land
along a river or stream or in a tidal
arra that is covered by water during a
flood.
Floor Sweep: Capture of heavier-than-
air gases that collect at floor level.
Flow Rate: The rate, expressed in
gallons-or liters-per-hour, at which a
fluid escapes from a hole or fissure in
a tank. Such measurements are also
made of liquid waste, effluent, and
surface water movement.
Flowmeter: A gauge indicating the
velocity of wastewater moving through
a treatment plant or of any liquid
moving through various industrial
processes.
Flue Gas Desulfurization: A technology
that employs a sorbent, usually lime or
limestone, to remove sulfur dioxide
from the gases produced by burning
fossil fuels. Flue gas desulfurization is
current state-.of-the art technology for
major SO2 emitters, like power plants.
Flue Gas: The air coming out of a
chimney after combustion in the burn-
er it is venting. It can include nitrogen
oxides, carbon oxides, water vapor,
sulfur oxides, particles and many
chemical pollutants.
Fluidized: A mass of solid particles
that is made to flow like a liquid by
injection of water or gas is said to have
been fluidized. In water treatment, a
bed of filter media is fluidized by
backwashing water through the filter.
Fluidized Bed Incinerator An inciner-
ator that uses a bed of hot sand or
other granular material to transfer
heat directly to waste. Used mainly for
destroying municipal sludge.
Fluoridation: The addition of n chemi-
cal to increase the concentration of
fluoride ions in drinking water to re-
duce the incidence of tooth decay in
children.
Flume: A natural or man-made chan-
nel that diverts water.
Fluorides: Gaseous, solid, or dissolved
compounds containing fluorine that re-
sult from industrial processes. Exces-
sive amounts in food can lead to fluoro-
sis.
Fluorocarbons (PCs): Any of a number
of organic compounds analogous to
hydrocarbons in which one or more
hydrogen atoms are replaced by fluo-
rine. Once used in the United States
as a propellant for domestic aerosols,
they are now found mainly in coolants
and some industrial processes. PCs
containing chlorine are called
chlorofluorocarbons (CFCs). They are
believed to be modifying the ozone
layer in the stratosphere, thereby
allowing more harmful solar radiation
to reach the Earth's surface.
Flush: 1. To open a cold-water tap to
clear out all the water which may have
been sitting for a long time in the
pipes. In new homes, to flush a system
means to send large volumes of water
gushing through the unused pipes to
remove loose particles of solder and
flux. 2. To force large amounts of water
through liquid to clean out piping or
tubing, storage or process tanks.
Flux: A flowing or flow.
Fly Ash: Non-combustible residual
particles expelled by flue gas.
Fogging: Applying a pesticide by rap-
idly heating the liquid chemical so that
it forms very fine droplets that resem-
ble smoke or fog. Used to destroy mos-
quitoes, black flies, and similar pests.
Food Chain: A sequence of organisms,
each of which uses the next, lower
member of the sequence as a food
source.
Formaldehyde: A colorless, pungent,
and irritating gas, CH20, used chiefly
as a disinfectant and preservative and
in synthesizing other compounds Like
resins.
Formulation: The substances compris-
ing all active and inert ingredients in
a pesticide.
Fonil Fuel: Fuel driyed from ancient
organic remains, e.g., peat, coal, crude
oil, and natural gas.
Freeboard: 1. Vertical distance from
the normal water surface to the top of
a confining wall. 2. Vertical distance
from the sand surface to the underside
of a trough in a sand filter.
Fresh Water Water that generally
contains less than 1,000 milligrams-
per-liter of dissolved solids,
Friable Asbestos: Any material con-
taining more than one percent asbes-
tos, and that can be crumbled or re-
duced to powder by hand pressure.
(May include previously non-friable
material which becomes broken or
damaged by mechanical force.)
Friable: Capable of being crumbled,
pulverized, or reduced to powder by
hand pressure.
Fuel Economy Standard: The Corpo-
rate Average Fuel Economy Standard
(CAFE) effective since 1978. It en-
hanced the national fuel conservation
effort imposing a miles-per-gallon floor
for motor vehicles.
Fuel Efficiency: The proportion of ener-
gy released by fuel combustionton that
is converted into useful energy.
Fuel Switching: 1. A precombustion
process whereby a low-sulfur coal is
used in place of a higher sulfur coal in
a power plant to reduce sulfur dioxide
emissions. 2. Illegally using leaded
gasoline in a motor vehicle designed to
use only unleaded.
Fugitive Emissions: Emissions not
caught by a capture system.
Fume: Tiny particles trapped in vapor
in a gas stream.
Fumigant: A pesticide vaporized to kill
pests. Used in buildings and green-
houses. -
Functional Equivalent: Term used to
describe EPA's decision-making process
and its relationship to the environmen- •
tal review conducted under the Nation-
al Environmental Policy Act (NEPA). A
review is considered functionally equiv-
alent when it addresses the substan-
tive components of a NEPA review.
Fungi: (Singular: Fungus) Molds, mil-
dews, yeasts, mushrooms, and puff-
balls, a group of organisms lacking in
chlorophyll (i.e., are not photosynthet-
ic) and which 'are usually non-mobile,
filamentous, and multicellular. Some
grow in soil, others attach themselves
to decaying trees and other plants
whence they obtain nutrients. Some
are pathogens, others stabilize sewage
and digest composted waste.
Fungicide: Pesticides which are used to
control, deter, or destroy fungi.
Fungistafc A chemical that keeps fungi
from growing.
Furrow Irrigation: Irrigation method in
which water travels through the field
by means of small channels between
each row or groups of rows.
Future Liability: Refers to potentially
responsible parties' obligations to pay
for additional response activities be-
yond those specified in the Record of
Decision or Consent Decree.
Game Fish: Species like trout, salmon,
or bass, caught for sport. Many of
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18
them show more sensitivity to environ-
mental change than "rough" fish.
Garbage: Animal and vegetable waste
resulting from the handling, storage,
sale, preparation, cooking, and serving
of foods.
Gas Chromatograph/Mass Spectrome-
ter Highly sophisticated instrument
that identifies the molecular composi-
- tion and. concentrations of various
chemicals in water and soil samples.
Gasahol: Mixture of gasoline and etha-
nol derived from fermented agricultur-
al products containing at least nine
percent ethanol. Gasohol emissions
contain less carbon monoxide than
those from gasoline.
Gasification: Conversion of solid mate-
rial such as coal into a gas for use as a
fuel.
Gasoline Volatility: The property of
gasoline whereby it evaporates into a
vapor. Gasoline vapor is a volatile
organic compound.
General Permit: A permit applicable to
a class or category of dischargers.
General Reporting Facility: A facility
having one or more hazardous chemi-
cals above the 10,000 pound threshold
for planning quantities. Such facilities
must file MSDS and emergency inven-
tory information with the SERC and
LEPC and local fire departments.
Generator 1. A facuity or mobile
source that emits pollutants into the
air or releases hazardous waste into
water or soil. 2. Any person, by site,
whose act or process produces regulat-
ed medical waste or whose act first
causes such waste to become subject to
regulation. In a case where more than
one person (e.g., doctors with separate
medical practices) is located in the
same building, each business entity is
a separate generator.
Genetic Engineering: A process of
inserting new genetic information into
existing cells in order to modify any
organism for the purpose of changing
one of its characteristics.
Geographic Information System (618):
A computer system designed for stor-
ing, manipulating analysing, and
displaying data in a geographic con-
text
Geological Log: A detailed description
of all underground features (depth,
thickness, type of formations) discov-
ered during the drilling of a well.
Geophysical Log: A record of the struc-
ture and composition of the earth en-
countered when drilling a well or simi-
lar type of test hold or boring.
Germicide: Any compound that kills
disease-causing microorganisms.
Giardia Lambiia: Protozoan in the
feces of man and animals that can
cause severe gastrointestinal ailments
when it contaminates drinking water.
Glovebag: A polyethylene or polyvinyl
chloride bag-like enclosure affixed
around an asbestos-containing source
(most often thermal system insulation)
permitting the material to be removed
while minimizing release of airborne
fibers in the surrounding atmosphere.
Gooseneck: A portion of a water service
connection between the distribution
system water main and a meter. Some-
times called a pigtail.
Grab Sample: A single sample collected
at a particular time and place that rep-
resents the composition of the water
only at that time and place.
Grain Loading: The rate at which
particles are emitted from a pollution
source. Measurement is made by the
number of grains per cubic foot of gas
emitted.
Granular Activated Carbon. Treatment:
A filtering system often used in small
water systems and individual homes to
remove organics. GAG can be highly ef-
fective in removing elevated levels of
radon from water.
Grassed Waterway: Natural or con-
structed watercourse or outlet that is
shaped or.graded and established in
suitable vegetation for the disposal of
runoff water without erosion.
Gray Water: Domestic wastewater
composed of wash water from kitchen,
bathroom, and laundry sinks, tubs,
and washers.
Greenhouse Effect: The wanning of the
Earth's atmosphere attributed to a
build-up of carbon dioxide or other gas-
es; some scientists think that this
build-up allows the sun's rays to heat
the Earth, while infra-red radiation
makes the atmosphere opaque to a
counterbalancing loss of heat
Grinder Pump: A mechanical device
that shreds solids and raises sewage to
a higher elevation through pressure
sewers.
Ground Coven Plants grown to keep
soil from eroding.
Ground Water: The supply of fresh
water found beneath the Earth's sur-
face, usually in aquifers, which supply
wells and springs. Because ground
water is a major source of drinking
water, there is growing concern over
contamination from leaching agricul-
tural or industrial pollutants or leak-
ing underground storage tanks.
Ground-Water Discharge: Ground
water entering near coastal waters
which has been contaminated by land-
fill leachate, deep well injection of
hazardous wastes, septic tanks, etc.
Ground Water Under the Direct In-
fluence (UDI) of Surface Water Any
water beneath the surface of the
ground with: 1. significant occurence of
insects or other microorganims, algae,
or large-diameter pathogens; 2. signifi-
cant and relatively rapid shifts in
water characteristcs such as turbidity,
temperature, conductivity, or pH which
closely correlate to climatological or
surface water conditions. Direct influ-
ence is determined for individual
sources in accordance with criteria
established by the state.
Gross Alpha/Beta Particle Activity: The
total radioactivity due to alpha or beta
particle emissions as inferred from
measurements on a dry sample.
Gully Erosion: Severe erosion in which
trenches are cut to a depth greater
than 30 centimeters (a foot). Generally,
ditches deep enough to cross with farm
equipment are considered gullies.
H
Habitat: The place where a population
(e.g., human, animal, plant, microor-
ganism) lives and its surroundings,
both living and non-living.
Habitat Indicator A physical attribute
of the environment measured to char-
acterize conditions necessary to sup-
port an organism, population, or com-
munity in the absence of pollutants,
e.g., salinity of esturarine waters or
substrate type in streams or lakes.
Half-Life: 1. The time required for a
pollutant to lose half its affect on the
environment. For example, the bio-
chemical half-life of DDT in the envi-
ronment is 15 years, of Radium. 1,580
years. 2. The time required for half of
the atoms of a radioactive element to
undergo self-transmutation or decay. 3.
The time required for the elimination
of one half a total dose from the body.
Halon: Bromine-containing compounds
with long atmospheric lifetimes whose
breakdown in the stratosphere causes
depletion of ozone. Halons are used in
fire-fighting.
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19
Hammennill: A high-speed machine
that uses hammers and cutters to
crush, grind, chip, or shred solid waste.
Hard Water Alkaline water containing
dissolved salts that interfere with some
industrial processes and prevent soap
from sudsing.
Hauler Garbage collection company
that offers complete refuse removal
service; many also will also collect
recyclables.
Hazard Communication Standard: An
OSHA regulation that requires chemi-
cal manufacturers, suppliers, and im-
porters to assess the hazards of the
chemicals that they make, supply, or
import, and to inform employers, cus-
tomers, and workers of these hazards
through MSDS sheets.
Hazard Evaluation: A component of
risk evaluation that involves gathering
and evaluating data on the types of
health injury or disease that may be
produced by a chemical and on the con-
ditions of exposure under which such
health effects are produced.
Hazard Identification: Determining if a
chemical can cause adverse health
effects in humans and what those
affects might be.
Hazardous Air Pollutants: Air pollut-
ants which are not covered by ambient
air quality standards but which, as
defined in the Clean Air Act, may
reasonably be expected to cause or
contribute to irreversible illness or
death. Such pollutants include asbes-
tos, beryllium, mercury, benzene, coke
oven emissions, radionuclides, and
vinyl chloride.
Hazardous Chemical: An EPA designa-
tion for any hazardous material requir-
ing an MSDS under OSHA's Hazard
Communication Standard. Such sub-
stances are capable of producing fires
and explosions or .adverse health ef-
fects like cancer and dermatitis. Haz-
ardous chemicals are distinct from
hazardous waste. (See: hazardous
waste.)
Hazardous Ranking System: The prin-
ciple screening tool used by EPA to
evaluate risks to public health and the
environment associated 'frith aban-
doned or uncontrolled hazardous waste
sites. The HRS calculates a score
based on the potential of hazardous
substances spreading from the site
through the air, surface water, or
ground water, and on other factors
such as density and proximity of hu-
man population. This score is the pri-
mary factor in deciding if the site
should be on the National Priorities
List and, if so, what ranking it should
have compared to other sites on the
list.
Hazardous Substance: 1. Any material
that poses a threat to human health
and/or the environment. Typical haz-
ardous substances are toxic, corrosive,
ignitable, explosive, or chemically re-
active. 2. Any substance designated by
EPA to be reported if a designated
quantity of the substance is spilled in
the waters of the United States or if
otherwise released into the environ-
ment.
Hazardous Waste: By-products of soci-
ety that can pose a substantial or po-
tential hazard to human health or the
environment when improperly man-
aged. Possesses at least one of four
characteristics (ignitability, corrosivity,
reactivity, or toxicity), or appears on
special EPA lists.
Hazardous Waste TjmHfill- An excavat-
ed or engineered site where hazardous
waste is deposited and covered.
Hazards Analysis: Procedures used to
(1) identify potential sources of release
of hazardous materials from fixed
facilities or transportation accidents;
(2) determine the vulnerability of a
geographical area to a release of haz-
ardous materials; and (3) compare haz-
ards to determine which present great-
er or lesser risks to a community.
Hazards Identification: Providing
information on which facilities have
extremely hazardous substances, what.
those chemicals are, how much there is
at each facility, how the chemicals are
stored, and whether they are used at'
high temperatures.
Health Advisory Level: A non-regulato-
ry health-based reference level of
chemical traces (usually in ppm) in
drinking water at which there are no
adverse health risks when ingested
over various periods of time. Such
levels are established for one day, 10
days, long-term and life-time exposure
periods. They contain a wide margin of
safety.
Health Ai
at An evaluation of
available data on existing or potential
risks to human, health posed by a
Superfund site. The Agency for Toxic
Substances and Disease Registry (ATS-
DR) of the Department of Health and
Human Services (DHHS) is required to
perform such an assessment at every
site on the National Priorities Last.
Heat Island Effect: A "dome" of ele-
vated temperatures over an urban area
caused by structural and pavement
heat fluxes, and pollutant emissions.
Heavy Metals: Metallic elements with
high atomic weights, e.g., mercury,
chromium, cadmium, arsenic, and lead;
can damage living things at low con-
centrations and tend to accumulate in
the food chain.
Heptachlor An insecticide that .was
banned on some food products in 1975
and all of them 1978. It was allowed
for use in seed treatment until 1983.
More recently it was found in milk and
other dairy products in Arkansas and
Missouri where dairy cattle were ille-
gally fed treated seed.
Herbicide: A chemical pesticide de-
signed to control or destroy plants,
weeds, or grasses.
Herbivore: An animal that feeds on
plants.
Heterotrophic Organisms: Species that
are dependent on organic matter for
food.
High-Density Polyethylene: A material
used to make plastic bottles and other
products that produces toxic fumes
when burned.
High-Level Radioactive Waste (HLW):
Waste generated in core fuel of a nu-
clear reactor or by nuclear fuel repro-
cessing; is a serious threat to anyone
who comes near the waste without shi-
elding. (See: low-level radioactive
waste.)
High-Level Nuclear Waste Facility:
Plant designed to handle disposal of
used nuclear fuel, high-level radioac-
tive waste, and plutonium waste.
High-Line Jumpers: Pipes or hoses
connected to fire hydrants and laid on
top of the ground to provide emergency
water service for an isolated portion of
a distribution system.
High-Risk Community: A community
located within the vicinity of numerous
sites of facilities or other potential
sources of environrnmental expo-
sure/health hazards which may result
in high levels of exposure to contami-
nants or pollutants.
Holding Pond: A pond or reservoir,
usually made of earth, built to store
polluted runoff.
Homeowner Water System: Any water
system which supplies piped water to
a single residence.
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20
Homogeneous Area: In accordance with
Asbestos Hazard and Emergency Re-
sponse Act (AHERA) definitions, an
area of surfacing materials, thermal
surface insulation, or miscellaneous
material that is uniform in color and
texture.
Hood Capture Efficiency: Ratio of the
emissions captured by a hood and dire-
cted into a control or disposal device;
expressed as a percent of all emissions.
Host: 1. In genetics, the organism,
typically a bacterium, into which a
gene from another organism is trans-
planted. 2. In medicine, an animal
infected or parasitized by another
organism.
Household Waste (Domestic Waste):
Solid waste, composed of garbage and
rubbish, which normally originated in
a private home or apartment house.
Domestic waste may contain a signifi-
cant amount of toxic or hazardous
waste.
Human Equivalent Dose: A dose
which, when administered to humans,
produces an effect equal to that pro-
duced by a dose in animals.
Human Exposure Evaluation: Describ-
ing the nature and size of the popula-
tion exposed to a substance and the
magnitude and duration of their expo-
sure.
Human Health Risk: The likelihood
that a given exposure or series of expo-
sures may have or will damage the
health of individuals.
Hydraulic Gradient: In general, the
direction of groundwater flow due to
changes in the depth of the water
table.
Hydrocarbons (HO Chemical com-
pounds that consist entirely of carbon
and hydrogen.
Hydrogen Sulfide (HS> Gas emitted
during organic decomposition. Also a
by-product of oil refining and burning.
Smells like rotten eggs and, in heavy
concentration, can kill or cause illness.
Hydrogeological Cycle: The natural
process recycling water from the atmo-
sphere down to (and through) the
earth and back to the atmosphere
again.
Hydrogeology: The geology of ground
water, with particular emphasis on the
chemistry and movement of water.
Hydrologic Cycle: Movement or ex-
change of water between the atmo-
sphere and earth.
Hydrology: The science dealing with
the properties, distribution, and cir-
culation of water.
Hydrophilic: Having a strong affinity
for water.
Hydrophobic: Having a strong aversion
for water.
Hydropneumatic: A water system,
usually small, in which a water pump
is automatically controlled by the pres-
sure in a compressed air tank.
Hypolimnion: Bottom waters of a ther-
mally stratified lake., The hypolimnion
of a eutrophic lake is usually low or
lacking in oxygen.
I
Identification Code or EPA I.D. Num-
ber The unique code assigned to each
generator, transporter, and treatment,
storage, or disposal facility by regu-
lating agencies to facilitate identifica-
tion and tracking of chemicals or haz-
ardous waste.
Ignitable: Capable of burning or caus-
ing a fire.
Imhoff Cone: A clear, cone-shaped con-
tainer used to measure the volume of
settleable solids in a specific volume of
water.
Immediately Dangerous to Life
Health CEDLH): The' maximum level to
which a healthy individual can be
exposed to a chemical for 30 minutes
and escape without suffering irrevers-
ible health effects or impairing symp-
toms. Used as a "level of concern."
(See: level of concern.)
Impermeable: Not easily penetrat-
ed. The property of a material or soil
that does not allow, or allows only with
great difficulty, the movement or pas-
sage of water.
Impoundment: A body of water or
sludge confined by a dam, dike, flood-
gate, or other barrier.
Command Post: A facility
located at a safe distance from an
emergency site, where the incident
commander, key staff, and technical
representatives can make decisions
and deploy emergency manpower and
equipment.
Command System (ICS): The
organizational arrangement wherein
one person, normally the Fire Chief of
the impacted district, is in charge of an
integrated, comprehensive emergency
response organization and the emer-
gency incident site, backed by an
Emergency Operations Center staff
with resources, information, and ad-
vice.
Incineration: A treatment technology
involving destruction of waste by con-
trolled burning at high temperatures,
e.g., burning sludge to remove the
water and reduce the remaining resi-
dues to a safe, non-burnable ash that
can be disposed of safely on land, in
some waters, or in underground loca-
tions.
Incineration at Sea: Disposal of waste
by burning at sea on specially-designed
incinerator ships.
Incinerator: A furnace for burning
waste under controlled conditions.
Incompatible Waste: A waste unsuit-
able for mixing with another waste or
material because it may react to form
a hazard.
Indicator: In biology, an organism, spe-
cies, or community whose characteris-
tics show the presence of specific envi-
ronmental conditions. 2. In chemistry,
a substance that shows a > visible
change, usually of color, at a desired
point in a chemical reaction. 3.A device
that indicates the result of a measu-
rement.
Indirect Discharge: Introduction of pol-
lutants from a non-domestic source
into a publicly owned waste-treatment
system. Indirect dischargers can be
commercial or industrial facilities
whose wastes enter local sewers.
Indirect Source: Any facility or build-
ing, property, road or parking area
that attracts motor vehicle traffic and,
indirectly, causes pollution.
Indoor Air The breathing air inside a
habitable structure or conveyance.
Indoor Air Pollution: Chemical, physi-
cal, or biological contaminants in in-
door air.
Indoor Climate: Temperature, humidi-
ty, lighting, and noise levels in a habit-
able structure or conveyance. Indoor
climate can affect indoor air pollution.
Industrial Pollution Prevention: Com-
bination of industrial source reduction
and toxic chemical use substitution
Industrial Source Reduction: Practices
that reduce the amount of any hazard-
ous substance, pollutant, or contami-
nant entering any waste stream or
otherwise released into the environ-
ment; also reduces the threat to public
health and the environment associated
with such releases. Term includes
equipment or technology modifications,
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21
substitution of raw materials, and
improvements in housekeeping, main-
tenance, training or inventory control.
Industrial Waste: Unwanted materials
from an industrial operation; may be
liquid, sludge, solid, or hazardous
waste.
Inert Ingredient: Pesticide components
such as solvents, carriers, dispers-
ants.and surfactants that are not ac-
tive against target pests. Not all inert
ingredients are, innocuous.
Inertia! Separator: A device that uses
centrifugal force to separate waste
particles.
Infectious Agent Any organism, such
as a virus or bacterium, that is path-
ogenic and capable of being communi-
cated by invasion and multiplication in
body tissues.
Infectious Waste: Hazardous waste
with infectious characteristics, includ-
ing: contaminated animal waste; hu-
man blood and blood products; isola-
tion waste, pathological waste; and
discarded sharps (needles, scalpels or
broken medical instruments.)
Infiltration: 1. The penetration of wa-
ter through the ground surface into
sub-surf ace soil or the penetration of
water from the soil into sewer or other
pipes through defective joints, connec-
tions, or manhole walls. 2. The tech-
nique of applying large volumes of
waste water to land to penetrate the
surface and percolate through the
. underlying soil. (See: percolation.)
Infiltration Gallery: A sub-surface
groundwater collection system, typical-
ly shallow in depth, constructed with
open-jointed or perforated pipes that
discharge collected water into a water-
tight chamber from which the water is
pumped to treatment facilities and into
the distribution system. Usually locat-
ed close to streams or ponds.
Infiltration Rate: The quantity of water
than can enter the soil in a specified
time interval.
Inflow: Entry of extraneous rain water
into a sewer system from sources other
than infiltration, such as basement
drains, manholes, storm drains, and
street washing.
Influent: Water, wastewater, or other
liquid flowing into a reservoir, basin,
or treatment plant.
Information File: In the Superfund
program, a file that contains accurate,
up-to-date documents on a Superfund
site. The file is usually located in a
public building (school, library, or city
hall) convenient for local residents.
Initial Compliance Period(water): The
first full three-year compliance period
which begins at least 18 months after
promulgation.
Injection Well: A well into which fluids
are injected for purposes such as waste
disposal, improving the recovery of
crude oil, or solution mining.
Injection Zone: A geological formation
receiving fluids through a well.
In-Ldne Filtration: Pre-treatment met-
hod in which chemicals are mixed by
the flowing water; commonly used in
pressure filtration installations. Elimi-
nates need for flocculation and sedi-
mentation.
Innovative Technologies: New or inven-
tive methods to treat effectively haz-
ardous waste and reduce risks to hu-
man health and the environment.
Inoculum: 1. Bacterium placed in com-
post to start biological action. 2. A
medium containing organisms that is
introduced into cultures or living or-
ganisms.
Inorganic Chemicals: Chemical sub-
stances of mineral origin, not of basi-
cally carbon structure.
Insecticide: A pesticide compound spe-
cifically used to kill or prevent the
growth of insects.
Inspection and MaiTit«tianc« (J/M): 1.
Activities to assure that vehicles' emis-
sions-controls work properly. 2. Also
applies to wastewater treatment plants
and other anti-pollution facilities and
processes.
Instream Use: Water use taking place
within a stream channel, e.g., hydro-
electric power generation, navigation,
water quality improvement, fish propa-
gation, recreation.
In-Situ Stripping: Treatment system
that remove or "strips" volatile organic
compounds from contaminated ground
or surface water by forcing an air-
stream through the water and causing
the compounds to evaporate.
Integrated Eipueure Assessment Cu-
mulative summation (over time) of the
magnitude of exposure to a toxic chem-
ical in all media.
Integrated Pest Management (TPM): A
mixture of chemical and other, non-pe-
sticide, methods to control pests.
Integrated Waste Management Using
a variety of practices to handle munici-
pal solid waste; can include source
reduction, recycling, incineration, and
landfilling.
Interceptor Sewers: Large sewer lines
that, in a combined system, control the
flow of sewage to the treatment plant.
In a storm, they allow some of the sew-
age to flow directly into a receiving
stream, thus keeping it from overflow-
ing onto the streets. Also used in sepa-
rate systems to collect the flows from
main and trunk sewers and carry them
to treatment points.
Interface: The common boundary be-
tween two substances such as a water
and a solid, water and a gas, or two
liquids such as water and oil.
Interim (Permit) Status: Period during
which treatment, storage and disposal
facilities coming under RCRA in 1980
are temporarily permitted to operate
while awaiting a permanent permit.
Permits issued under these circum-
stances are usually called "Part A" or
"Part B" permits.
Interstate Carrier Water Supply: A
source of water for drinking and sani-
tary use on planes, buses, trains, and
ships operating in more than one state.
These sources are federally regulated.
Interstate Commerce Clause: A clause
of the U.S. Constitution which reserves
to the federal government the right to
regulate the conduct of business across
state lines. Under this clause, for ex-
ample, the U.S. Supreme Court has
ruled that states may not inequitably
restrict the disposal out-of-state wastes
in their jurisdictions.
Interstate Waters: Waters that flow
across or form part of state or inter-
national boundaries, e.g., the Great
Lakes, the Mississippi River, or coastal
waters.
Interstitial Monitoring: The continuous
surveillance of the space between the
walls of an underground storage tank.
Inventory (TSCA): Inventory of chemi-
cals produced pursuant to Section 8 (b)
of the Toxic Substances Control Act.
Inversion: A layer of warm air prevent-
ing the rise of cooling air and pollut-
ants trapped beneath it. Can cause an
air pollution episode. ,
Ion: An electrically charged atom that
can be drawn from waste water during
electrodialysis.
J.S.
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22
Ion Exchange Treatment: A common
water-softening method often found on
a large scale at water purification
plants that remove some organics and
radium by adding calcium oxide or
calcium hydroxide to increase the pH
to a level where the metals will pre-
cipitate out.
lonization Chamber: A device that
measures the intensity of ionizing
radiation. ' . .
Ionizing Radiation: Radiation that can
strip electrons from atoms, .i.e., alpha,
beta, and gamma radiation.
Irradiated Food: Food subject to brief
radioactivity, usually gamma rays, to
kill insects, bacteria, and mold, and to
permit storage without refrigeration.
Irradiation: Exposure to radiation of
wavelengths shorter than those of visi-'
ble light (gamma, x-ray, or ultraviolet),
for medical purposes, to sterilize milk
or other foodstuffs, or to induce poly-
merization of monomers or vulcaniza-
tion of rubber.
Irreversible Effect; Effect characterized
by the inability of the body to partially
or fully repair injury caused by a toxic
agent.
Irrigation: Applying water or waste-
water to land areas to supply the. wa-
ter and nutrient needs of plants.
Irrigation Efficiency: The amount of
water stored in the crop root zone com-
pared to the amount of irrigation water
applied.
Irrigation Return Flow: Surface and
subsurface water which leaves the field
following application of irrigation wa-
ter.
Irritant A substance that can cause
irritation of the skin, eyes, or respira-
tory system. Effects may be acute from
a single high-level exposure, or chronic
from repeated low-level exposures to
such compounds as chlorine, nitrogen
dioxide, and nitric acid.
Isotope: A variation of an element that
has the same atomic number of pro-
tons but a different weight because of
the number of neutrons. Various iso-
topes of the same element may have
different radioactive behaviors, some
are highly unstable..
Jar Test: A laboratory procedure that
simulates a water treatment plant's co-
agulation/Qocculation units with dif-
fering chemical doses, mix speeds, and
settling times to estimate the mini-
mum or ideal coagulant dose required
to achieve certain water quality goals.
Karat: A geologic formation of irregular
limestone deposits with sinks, under-
ground streams, and caverns.
Kinetic Energy: Energy possessed by a
moving body of water as a result of its
motion.
Kinetic Rate Coefficient: A number
that describes the rate at which a
water constituent such as a biochemi-
cal oxygen demand or dissolved oxygen
rises or falls.
Lagoon: 1. A shallow pond where sun-
light, bacterial action, and oxygen
work to purify wastewater; also used
for storage of wastewater or spent
nuclear fuel rods. 2. Shallow body of
water, often separated from the sea by
coral reefs or sandbars.
Land Application: Discharge of waste-
water onto the ground for treatment or
reuse. (See: irrigation.)
Land Ban: Phasing out of land disposal
of most untreated hazardous wastes,
as mandated by the 1984 RCRA
amendments.
Land Fanning (of waste): A disposal
process in which hazardous waste de-
posited on or in the soil is degraded
naturally by microbes.
? i. Sanitary landfills are dis-
posal sites for non-hazardous solid
wastes spread in layers, compacted to
the smallest practical volume, and
covered by material applied at the end
of each operating day. 2. Secure chemi-
cal landfills are disposal sites for haz-
ardous waste, selected and designed to
the chance of release of haz-
ardous substances into the environ-
ment.
Landscape: The traits, patterns, and
structure of a specific geographic area,
including its biological composition, its
physical environment, and its anthro-
pogenic or social patterns. An area
where interacting ecosystems are
grouped and repeated in similar form.
Landscape Characterization: Docu-
mentation of the traits and patterns of
the essential elements of the land-
scape.
Landscape Ecology: The study of the
distribution patterns of communities
and ecosystems, the ecological process-
es that affect those patterns, and
changes in pattern and process over
time.
Landscape Indicator A measurement
of the landscape, calculated from
mapped or remotely sensed data, used
to describe spatial patterns of land use
and land cover across a geographic
area. Landscape indicators may be
useful as measures of certain kinds of
environmental degradation such as
forest fragmentation.
Langelier Index (LI): An index reflect-
ing the equilibrium pH of a water with
respect to calcium and alkalinity; used
in stabilizing water to control both
corrosion and scale deposition.
Large Quantity Generator Person or
facility generating more than 2200
pounds of hazardous waste per month.
Such generators produce about 90 per-
cent of the nation's hazardous waste,
and are subject to all RCRA require-
ments.
Large Water System: A water system
that services more than 50,000 custom-
era.
Latency: Time from the first exposure
of a chemical until the appearance of a
toxic effect.
Lateral Sewers: Pipes that run under
city streets and receive the sewage
from homes and businesses, as opposed
to domestic feeders and main trunk
lines.
Weir Sedunention basin
overflow weir.
LC50/Lethal c Concentration: Median
level concentration, a standard mea-
sure of toxitity. It tells how much of a
substance is needed to kill half of a
group of experimental organisms in a
given time. (See: LD50.)
Lt> 50/ Lethal Dose: The dose of a
toxicant that will kill 50 percent of the
test organisms within a designated
period. The lower the LD 50, the more
toxic the compound.
Leachate: Water that collects contami-
nants as it trickles through wastes,
pesticides or fertilizers. Leaching may
occur in farming areas, feedlots, and
landfills, and may result in hazardous
substances entering surface water,
ground water, or soil.
Leachate Collection System: A system
that gathers leachate and pumps it to
the surface for treatment.
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23
phing; The process by which soluble
constituents are dissolved and filtered
through the soil by a percolating fluid.
(See: leachate.)
Lead (Pb): A heavy metal that is haz-
ardous to health if breathed or swal-
lowed. Its use in gasoline, paints, and
plumbing compounds has been sharply
restricted or eliminated by federal laws
and regulations. (See: heavy metals.)
Lead Service Lin«v A service line made
of lead which connects the water to the
building inlet and any lead fitting con-
nected to it.
Legionella: A genus .of bacteria, some
species of which have caused a type of
pneumonia called Legionaires Disease.
Level of Concern (LOG): The concen-
tration in air of an extremely hazard-
ous substance above which there may
be serious immediate health effects to
anyone exposed to it for short periods
Lifetime Exposure: Total amount of
exposure to a substance that a human
would receive in a lifetime (usually
assumed to be 70 years).
Lift: In a sanitary landfill, a compacted
layer of solid waste and the top layer
of cover material.
T.ifHng Station: (See: pumping station.)
Limestone Scrubbing: Use of a lime-
stone and water solution to remove
gaseous stack-pipe sulfur before it
reaches the atmosphere.
Limited Degradation: An. environmen-
tal policy permitting some degradation
of natural systems but terminating at
a level well beneath an established
health standard.
Limiting Factor A condition whose ab-
sence or excessive concentration, is
incompatible with the needs or toler-
ance of a species or population and
which may have a negative influence
on their ability to thrive, survive.
Limnology: The study of the physical,
chemical, hydrological, and biological
aspects of fresh water bodies.
- A pesticide that causes ad-
verse health effects in domestic water
supplies and is toxic to freshwater fish
and aquatic life.
Linen LA relatively impermeable
barrier designed to keep leachate in-
side a landfill. Liner materials include
plastic and dense clay. 2. An insert or
sleeve for sewer pipes to prevent leak-
age or infiltration.
Lipid Solubility: The maximum concen-
tration of a chemical that will dissolve
in fatty substances. Lipid soluble sub-
stances are insoluble in water. They
will very selectively disperse through
the environment via uptake in living
tissue.
Liquefaction: Changing a solid into a
liquid.
Liquid Injection Incinerator Common-
ly used system that relies on .high
pressure to prepare liquid wastes for
incineration, breaking them up into
tiny droplets to allow easier combus-
tion.
List Shorthand term for EPA list of
violating facilities or firms debarred
from obtaining government contracts
because they violated certain sections
of the Clean Air or Clean Water Acts.
The list is maintained by The Office of
Enforcement and Compliance Moni-
toring.
Listed Waste: Wastes listed as hazard-
ous under RCRA but which have not
been subjected to the Toxic Character-
istics Listing Process because the dan-
gers they present are considered self-
•evident.
Litter" The highly visible portion of
solid waste carelessly discarded outside
the regular garbage and trash collec-
tion and disposal system.
Littoral Zone: 1. That portion of a body
of fresh water extending from the
shoreline lakeward to the limit of occu-
pancy of rooted plants. 2. A strip of
land along the shoreline between the
high and low water levels.
Local Education Agency (LEA): In the
asbestos program, an educational
agency at the local level that exists
primarily to operate schools or to con-
tract for educational services, including
primary and secondary public and
private schools. A single, unaffiliated
school can be considered an LEA for
AHERA purposes.
Local Emergency Planning Committee
(LEPO A committee appointed by the
State Emergency Response Commis-
sion, as required by SARA Title III, to
formulate a comprehensive emergency
plan for its jurisdiction.
Low NO, Burners: One of several com-
bustion technologies used to reduce
emissions of Nitrogen Oxides (NO1.)
Loweat-Oberved-Adverse-Effect Level:
The lowest dose in an experiment
which produced an observable adverse
effect
Low-Level Radioactive Waste (LLRW):
Wastes less hazardous than most of
those associated with nuclear reactor;
generated by hospitals, research labo-
ratories, and certain industries. The
Department of Energy, Nuclear Regu-
latory Commission, and EPA share
responsibilities for managing them.
(See: high-level radioactive wastes.)
Lower Explosive Limit (LEL): The con-
centration of a compound in air below
which the mixture will not catch on
fire.
Lowest Achievable Emission Rate:
Under the Clean Air Act, the rate of
emissions that reflects (1) the most
stringent emission limitation in the im-
plementation plan of any state for such
source unless the owner or operator
demonstrates such limitations are not
achievable; or (2) the most stringent
emissions limitation achieved in prac-
tice, whichever is more stringent. A
proposed new or modified source may
not emit pollutants in excess of exist-
ing new source standards.
M
Magnetic Separation: Use of magnets
to separate .ferrous materials from
mixed municipal waste stream.
Managerial Controls: Methods of
nonpoint source pollution control based
on decisions about managing agricul-
tural wastes or application times or
rates for agrochemicals.
Mandatory Recycling: Programs which
by law require consumers to separate
trash so that some or all recyclable
materials are recovered for recycling
rather than going to landfills.
Man-Made Beta Particle and Photon
Emitters: All radionuclides emitting
beta particles and/or photons listed in
Maximum Permissible Body Burdens
and Maximum Permissible Concentra-
tions of Radionuclides in Air and Wa-
ter for Occupational Exposure.
Manual Separation: Hand sorting of
reyclable or compostable materials in
waste.
Major Modification: This term is used
to define modifications of major sta-
tionary sources of emissions with re-
spect to Prevention of Significant Dete-
rioration and New Source Review un-
der the Clean Air Act.
Major Stationary Sources: Term used
to determine the applicability of Pre-
vention of Significant Deterioration
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24
and new source regulations. In a
nonattainment area, any stationary
pollutant source with potential to emit
more than 100 tons per year is consid-
ered a major stationary source. In PSD
areas the cutoff level may be either
100 or 250 tons, depending upon the
source.
Majors: Larger publicly owned treat-
ment works (POTWs) with flows equal
to at least one million gallons per day
(mgd) or servicing population equiva-
lent to 10,000 persons; certain other
POTWs having significant water quali-
ty impacts. (See: minors.)
Management Plan: Under the Asbestos
Hazard Emergency Response Act
(AHERA), a document that each Local
Education Agency is required to pre-
pare, describing all activities planned
and undertaken by a school to comply
with AHERA regulations, including
building inspections to identify asbes-
tos-containing materials, response
actions, and operations and mainte-
nance programs to minimize the risk of
exposure.
Manifest System: Tracking of hazard-
ous waste from "cradle to grave" (gen-
eration through disposal) with accom-
panying documents known as mani-
fests. (See: cradle to grave.)
Manual Separation: Hand separation
of compostable or recyclable material
from waste.
Manufacturers Formulation: A list of
substances or component parts as de-
scribed by the maker of a coating,
pesticide, or other product containing
chemicals or other substances.
Margin of Safety. Maximum amount of
exposure producing no measurable
effect in animals (or studied humans)
divided by the actual amount of human
exposure in a population.
Marine Sanitation Device: Any equip-
ment or process installed on board a
vessel to receive, retain, treat, or dis-
charge sewage.
Marsh: A type of wetland that does not
accumulate appreciable peat deposits
and is dominated by herbaceous vege-
tation. Marshes may be either fresh or
saltwater, tidal or non-tidal. (See:
wetlands.)
Material Category: In the asbestos pro-
gram, broad classification of materials
into thermal surfacing insulation, sur-
facing material, and miscellaneous
material.
Materials Recovery Facility: A facility
that processes residentially collected
mixed recyclables into new products
available for market.
Material Type: classification of sus-
pect material by its specific use or
application, e.g., pipe insulation, fire-
proofing, and floor tile.
Material Safety Data Sheet (MSDS): A
compilation of information required
under the OSHA Communication Stan-
dard on the identity of hazardous
chemicals, health, and physical haz-
ards, exposure limits, and precautions.
Section 311 of SARA requires facilities
to submit MSDSs under certain cir-
cumstances:
Materials Recovery Facility (MRF):
Facility that processes residentially
collected mixed recyclables into new
products.
Maximum Contaminant Level: The
maximum permissible level of a con-
taminant in water delivered to any
user of a public system. MCLs are
enforceable standards.
Contaminant Level Goal
(MCLG): Under the Safe Drinking
Water Act, a non-enforceable, concen-
tration of a drinking water contami-
nant, set at the level at which no
known or anticipated adverse effects
on human health occur and which
allows an adequate safety margin.
The MCLG is usually the starting
point for determining the regulated
Maximum Contaminant Level. (See;
Maximum Contaminant Level.)
Maximum Tolerated Dose: The maxi-
mum dose that an animal species ran
tolerate for a major portion of its life-
time without significant impairment or
toxic effect other than carcinogenicity.
M«M»imiiiMil Aeration: Use of mechani-
cal energy to inject air into water to
cause a waste stream to absorb oxy-
gen.
M«n4»«niMil Separation: Using mechan-
ical mnana to separate waste into vari-
ous components.
MiM-haniral Turbulence: Random irreg-
ularities of fluid motion in air caused
by buildings or other non-thermal,
processes.
Madia: Specific environments-air, wa-
ter, soil-which are the subject of regu-
latory concern and activities.
Medical Surveillance: A periodic com-
prehensive review of a worker's health
status; acceptable elements of such
surveillance program are listed in the
Occupational Safety and Health Ad-
ministration standards for asbestos.
Medical Waste: Any solid waste gener-
ated in the diagnosis, treatment, or
immunization of human beings or ani-
mals, in research pertaining thereto, or
in the. production or testing of
biologicals, .excluding hazardous waste
identified or listed under 40 CFR Part
261 or any household waste as defined
in 40 CFR Sub-section 261.4 (bXD).
Medium-size Water System: A water
system that serves 3,300 to 50,000
customers.
Meniscus: The curved top of a column
of liquid in a small tube.
Mercury: A heavy metal that can accu-
mulate in the environment and is high-
ly toxic if breathed or swallowed. (See:
heavy metals.)
Mesotrophic Reservoirs and lakes
which contain moderate quantities of
nutrients and are moderately product-
ive in terms of aquatic animal and
plant life.
Metabolites: Any substances produced
by biological processes, such as those
from pesticides.
Metalimnion: The middle layer of a
thermally stratified lake or reservoir.
In this layer there is a rapid decrease
in temperature with depth. Also called
thermocline.
Methane: A colorless, nonpoisonous,
flammable gas created by anaerobic
decomposition of organic compounds.
Methanol: An alcohol that can be used
as an alternative fuel or as a gasoline
additive. It is less volatile than gaso-
line; when blended with gasoline it
lowers the carbon monoxide emissions
but increases hydrocarbon emissions.
Used as pure fuel, its emissions are
less ozone-forming than those from
gasoline.
Method 18: An EPA test method which
uses gas chromatographic techniques
to measure the concentration of vola-
tile organic compounds in a gas
stream.
Method 24: An EPA reference method
to determine density, water content
and total volatile content (water and
VOC) of coatings.
Method 25: An EPA reference method
to determine the VOC concentration in
a gas stream.
Methoxychlor: Pesticide that causes
adverse health effects in domestic
water -supplies and is toxic to fresh-
water and marine aquatic life.
Methyl Orange Alkalinity: A measure
of the total alkalinity in a water sam-
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25
pie in wich the color of methyl orange
reflects the change in level.
Microbial Growth: The activity and
growth of microorganisms such as
bacteria, algae, diatoms, plankton, and
fungi.
Microclimate: The localized climate
conditions within an urban area or
neighborhood.
Microbial Pesticide: A microorganism
that is used to control a pest, but of
minimum toxicity to man.
Million-gallons Per Day (MOD): A
measure of water flow.
Minimization: A comprehensive pro-
gram to minimize or eliminate wastes,
usually applied to wastes at their point
of origin. (See: waste minimization.)
Mining of an Aquifer Withdrawal over
a period of time of ground water that
exceeds the rate of recharge of the
aquifer.
Minors: Publicly owned treatment
works with flows less than 1 million
gallons per day. (See: majors.)
Miscellaneous ACM: Interior asbestos-
containing building material or struc-
tural components, members or fixtures,
such as floor and ceiling tiles; does not
include surfacing materials or thermal
system insulation.
Miscellaneous materials: Interior
building materials on structural com-
ponents, such as floor or ceiling tiles.
Miscible Liquids: Two or more liquids
that can be mixed and will remain
mixed under normal conditions.
Missed Detection: The situation that
occurs when a test indicates that a
tank is "tight" when in fact it is leak-
ing.
Mist: Liquid particles measuring 40 to
500 microns, formed by condensation of
vapor. By comparison, fog particles are
smaller than 40 microns.
Mitigation: Measures taken to reduce
adverse impacts on the environment.
Mixed Funding: Settlements in which
potentially responsible parties and
EPA share the cost of a response ac-
tion.
Mixed Liquor: A mixture of activated
sludge and water containing organic
matter undergoing activated sludge
treatment in an aeration tank.
Mobile Incinerator Systems: Hazardous
waste incinerators that can be trans-
ported from one site to another.
Mobile Source: Any non-stationary
source of air pollution such as cars,
trucks, motorcycles, buses, airplanes,
locomotives.
Model Plant: A hypothetical plant
design used for developing economic,
environmental, and energy impact
analyses as support for regulations or
regulatory guidelines; first step in
exploring the economic impact of a
potential NSPS.
Modified Source: The enlargement of a
major stationery pollutant sources is
often referred to as modification, im-
plying that more emissions wil occur.
Molecule: The smallest division of a
compound that still retains or exhibits
all the properties of the substance.
Molten Salt Reactor A thermal treat-
ment unit that rapidly heats waste in
a heat-conducting fluid bath of car-
bonate salt.
Monitoring: Periodic or continuous sur-
veillance or testing to determine the
level of compliance with statutory re-
quirements and/or pollutant levels in
various media or in humans, plants,
and animals.
Monitoring Well: 1. A well used to
obtain water quality samples or mea-
sure groundwater levels. 2. Well drilled
at a hazardous waste management
facility or Superfund site to collect
ground-water samples for the purpose
of physical, chemical, or biological
analysis to determine the amounts,
types, and distribution of contaminants
in the ground water beneath the site.
Monoclonal Antibodies: (Also called
MABs and MCAs) 1. Man-made clones
of a molecule, produced in quantity for
medical or research purposes. 2. Mole-
cules of living organisms that selec-
tively find and attach to other mole-
cules to which their structure conforms
exactly. This could also apply to equiv-
alent activity by chemical molecules.
Monomictic Lakes and reservoirs
which are relatively deep, do not freeze
over during winter, and undergo a
single stratification and mixing cycle
during the year (usually in the fall).
Moratorium: During the negotiation
process, a period of 60 to 90 days dur-
ing which EPA and potentially respon-
sible parties may reach settlement but
no site response activities can be con-
ducted.
Morbidity: Rate of disease incidence.
Most Probable Number The most
probable number of colifonn-group
organisms per unit of volume of a
water sample
Muck Soils: Earth made from decaying
plant materials.
Mudballs: Round material that forms
in filters and gradually increases in
size when not removed by backwash-
ing.
Mulch: A layer of material (wood chips,
straw, leaves, etc.) placed around
plants to hold moisture, prevent weed
growth, and enrich or sterilize the soil.
Multiple Use: Use of land for more
than one purpose; i.e., grazing of live-
stock, watershed and wildlife protec-
tion, recreation, and timber produc-
tion. Also applies to use of bodies of
water for recreational purposes, fish-
ing, and water supply.
Multistage Remote Sensing: A strate-
gy for landscape characterization that
involves gathering and analyzing infor-
mation at several geographic scales,
ranging from generalized levels of
detail at the national level through'
high levels of detail at the local scale.
Municipal Discharge: Discharge of
effluent from waste water treatment
plants which receive waste water from
households, commercial establish-.
ments, and industries. Combined
sewer/separate storm overflows are in-
cluded in this category.
Municipal Sewage: Wastes (mostly liq-
uid) orginating from a community; may
be composed of domestic wastewaters
and/or industrial discharges.
Mutagen/Mutagenitity: An agent that
causes a permanent genetic change in
a cell other than that which occurs
during normal growth. Mutagenicity is
the capacity of a chemical or physical
agent to cause such permanent chang-
es.
N
National Ambient Air Quality Stan-
dards (NAAQS): Standards established
by EPA that apply for outside air
throughout the country. (See: criteria
pollutants, state implementation plans,
emissions trading.)
National Emissions Standards For
Hazardous Air Pollutants (NESHAPS):
Emissions standards set by EPA for an
air pollutant not covered by NAAQS
that may cause an increase in fatali-
ties or in serious, irreversible, or inca-
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26
pacitating illness. Primary standards
are designed to protect human health,
secondary standards to protect public
welfare (e.g., building facades, visi-
bility, crops, and domestic animals).
National Estuary Program: A program
established under the Clean Water Act
Amendments of 1987 to develop and
implement conservation and manage-
ment plans for protecting estuaries
and restoring and maintaining their
chemical, physical, and biological in-
tegrity, as well as controlling point and
nonpoint pollution sources.
National Interim Primary Drinking
Water Regulations: Commonly referred
to as NIPDWRs.
National Municipal Plan: A policy
created in 1984 by EPA and the states
to bring all publicly owned treatment
works (POTWs) into compliance with
Clean Water Act requirements.
National Oil and Hazardous Substanc-
es Contingency Plan (NOHSCP/NCP):
The federal regulation that guides
determination of the sites to be correct-
ed under both the Superfund program
and the program to prevent or control
spills into surface waters or elsewhere.
National Pollutant Discharge
tion System (NFDES): A provision of
the Clean Water Act which prohibits
discharge of pollutants into waters of
the United States unless a special
permit is issued by EPA, a state, or,
where delegated, a Native American
tribal government.
National Priorities List (NFL): EPA's
list of the most serious uncontrolled or
abandoned hazardous waste sites iden-
tified for possible long-term remedial
action under Superfund. The list is
based primarily on the score a site
receives from the Hazard Ranking
System. EPA is required to update the
NFL at least once a year. A site must
be on the NPL to receive money from
the Trust Fund for remedial action.
National Response Team (NRT): Rep-
resentatives of 13 federal agencies
that, as a team, coordinate federal
responses to nationally significant
incidents of pollution (an oil spill, a
major chemical release, or a Superfund
response action) and provide advice
and technical assistance to the re-
sponding agency(ies) before and during
a response action.
National Response Center: The federal
operations center that receives notifica-
tions of all releases of oil and hazard-
ous substances into the environment;
open 24 hours a day, is operated by the
U.S. Coast Guard, which evaluates all
reports and notifies the appropriate
agency.
National Secondary Drinking Water
Rregulations: Commonly referred to as
NSDWRs.
Navigable Waters: Traditionally, wa-
ters sufficiently deep and wide for
navigation by all, or specified vessels;
such waters in the United States come
under federal jurisdiction and are
protected by certain provisions of the
Clean Water Act.
Necrosis: Death of plant or animal
cells or tissues. In plants, necrosis can
discolor stems or leaves or kill a plant
entirely.
Negotiations: (Under Superfund) After
potentially responsible parties are
identified for a site, EPA coordinates
with them to reach a settlement that
will result in the PRP paying for or
conducting the cleanup under EPA su-
pervision. If negotiations fail, EPA can
order the PRP to conduct the cleanup
or EPA can pay for the cleanup 'using
Superfund monies and then sue to
recover the costs.
Nematocide: A chemical agent which is
destructive to nematodes.
Nephelometric Method of of measuring
turbidity in a water sample by passing
light through the sample and measur-
ing the amount of the light that is de-
flected.
Netting: A concept in which all emis-
sions sources in the same area that are
owned or controlled by a single compa-
ny are treated as one large source,
thereby allowing flexibility in control-
ling individual sources in order to meet
a single emissions standard. (See: bub-
ble)
Neutralization: Decreasing the acidity
or alkalinity of a substance by adding
alkaline or acidic materials, respec-
tively.
New Source: Any stationary source
built or modified after publication of
final or proposed regulations that pre-
scribe a given standard of perfor-
mance.
New Source Performance Standards
(NSPS> Uniform national EPA air
emission and water effluent standards
which limit the amount of pollution
allowed from new sources or from
modified existing sources.
New Source Review (NSR> Clean Air
Act requirement that State Implemen-
tation Plans must include a permit re-
view that applies to the construction
and operation of new and modified
stationary sources in nonattainment
areas to assure attainment of national
ambient air quality standards.
Nitrate: A compound containing nitro-
gen that can exist in the atmosphere
or as a dissolved gas in water and
which can have harmful effects on
humans and animals. Nitrates in wa-
ter can cause severe illness in infants
and domestic animals. A plant nutrient
and inorganic fertilizer, nitrate is
found in septic systems, animal feed
lots, agricultural fertilizers, manure,
industrial waste waters, sanitary land-
fills, and garbage dumps.
Nitric Oxide (NO): A gas formed by
combustion under high temperature
and high pressure in an internal com-
bustion engine; changes into nitrogen
dioxide in the ambient air and con-
tributes to photochemical smog.
Nitrification: The process whereby
ammonia in wastewater is oxidized to
nitrite and then to nitrate by bacterial
or chemical reactions.
Nitrilotriacetic Acid (NTA): A com-
pound now replacing phosphates in
detergents:
Nitrite: 1. An intermediate in the pro-
cess of nitrification. 2. Nitrous oxide
salts used in food preservation
Nitrogen Dioxide (NOj): The result of
nitric oxide combining with oxygen in
the atmosphere; major component of
photochemical smog.
Nitrogen Oxide (NO,): Product of com-
bustion from transportation and sta-
tionary sources and a major contribu-
tor to the formation of ozone in the
troposphere and to acid deposition.
Nitrogenous Wastes: Animal or vege-
table residues that contain significant
amounts of nitrogen.
Nitrophenola: Synthetic organopestic-
ides containing carbon, hydrogen, ni-
trogen, and oxygen.
Noble Metal Chemically inactive metal
such as gold; does not corrode easily.
No Further Remedial Action Planned:
Determination made by EPA following
a preliminary assessment that a site
does not pose a significant risk and so
requires no further activity under
CERCLA.
Noise: Product-level or product-volume
changes occurring during a test that
are not related to a leak but may be
mistaken for one.
Non-Attainment Area: Area that does
not meet one or more of the National
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27
Ambient Air Quality Standards for the
criteria pollutants designated in the
Clean Air Act.
Non-Binding Allocations of Responsi-
bility (NEAR): Process for EPA to pro-
pose a way for potentially responsible
parties to allocate costs among them-
selves.
Non-Community Water System: A pub-
lic water system that is not a commu-
nity water system, e.g., the water sup-
ply at a camp site or national park.
.Non-Compliance Coal: Any coal that
emits greqter than 3.0 pounds of sulfur
dioxide per million BTU when burned.
Also known as high-sulfur coal.
Non-Contact Cooling Water Water
used for cooling which does not come
into direct contact with any raw mate-
rial, product, byproduct, or waste.
Non-Conventional Pollutant: Any pol-
lutant not statutorily listed or which is
poorly understood by the scientific
community.
Non-degradation: An environmental
policy which disallows any lowering of
naturally occurring quality regardless
of preestablished health standards.
Nondischarging Treatment Plant: A
treatment plant that does not dis-
charge treated wastewater into any
stream or river. Most are pond systems
that dispose of the total flow they re-
ceive by means of evaporation or perco-
lation to groundwater, or facilities-that
dispose of their effluent by recycling or
reuse (e.g., spray irrigation or ground-
water discharge).
Nonfriable Asbestos-containing Materi-
als: Any material containing more than
one percent asbestos (as determined by
Polarized Light Microscopy) that, when
dry, cannot be crumbled, pulverized, or
reduced to powder by hand pressure.
Non-ionizing Electromagnetic Radia-
tion: 1. Radiation that does not change
the structure of atoms but does, heat
tissue and may cause harmful biologi-
cal effects. 2. Microwaves, radio waves,
and low-frequency electromagnetic
fields from high-voltage transmission
lines.
Non-Point Source: Diffuse pollution
sources (i.e., without a single point of
origin or not introduced into a receiv-
ing stream from a specific outlet). The
pollutants are generally carried off the
land by storm water. Common non-
point sources are agriculture, forestry,
urban, mining, construction, dams,
channels, land disposal, , saltwater
intrusion, and city streets.
Non-potable: Water that is unsafe or
unpalatable to drink because it con-
tains . pollutants, contaminants, min-
erals, or infective agents.
Non-Road Emissions: Pollutants emit-
ted by combustion engines on farm and
construction equipment, gasoline-pow-
ered lawn and garden equipment, and
power boats and outboard motors.
Non-Transient Non-Community Water
System: A public water system that
regularly serves at least 25 of the
same non-resident persons per day for
more than six months per year.
No Observable Adverse Effect Level
(NOAEL): From long-term toxicologi-
cal studies of agricultural chemical
active ingredients, levels which indi-
cate a safe, lifetime exposure level for
a given chemical.
Notice of Deficiency: An EPA request
to a facility owner or operator request-
ing additional information before a
preliminary decision on a permit appli-
cation can be made.
Notice of Intent to Deny: Notification
by EPA of its preliminary intent to
deny a permit application.
No Till: Planting crops without prior
seedbed preparation, into an existing
cover crop, sod, or crop residues, and
eliminating subsequent tillage opera-
tions.
Nuclear Reactors and Support Facili-
ties: Uranium mills, commercial power
reactors, fuel reprocessing plants, and
uranium enrichment facilities.
Nuclear Winter Prediction by some
scientists that smoke and debris rising
from massive fires of a nuclear war
could block sunlight for weeks or
months, cooling the earth's surface and
producing climate changes that could,
for example, negatively effect world ag-
ricultural and weather patterns.
Nuclide: An atom characterized by the
number of .protons, neturons, and ener-
gy in the nucleus.
Nutrient: Any substance assimilated
by living things that promotes growth.
The term is generally applied to ni-
trogen and phosphorus in wastewater,
but is also applied to other essential
and trace elements.
Nutrient Pollution: Contamination of
water resources by excessive inputs of
nutrients. In surface waters, excess
algal production is a major concern.
Ocean Discharge Waiver A variance
from Clean Water Act requirements for
discharges into marine waters'.
Odor Threshold: The minimum odor of
a water sample that can just be detect-
ed after successive dilutions with odor-
less water. Also called threshold odor.
Offsets: A concept whereby emissions
from proposed new or modified station-
ary sources are balanced by reductions
from existing sources to stabilize total
emissions. (See: bubble, emissions
trading, netting.)
Off-Site Facility: A hazardous waste
treatment, storage or disposal area
that is located away from the generat-
ing site.
Offstream Use: Water withdrawn from
surface or groundwater sources for use
at another place.
Oil Desulfurization: Widely used
precombustion method for reducing
sulfur dioxide emissions from oil-burn-
ing power plants. The oil is treated
with hydrogen, which removes some of
the sulfur by forming hydrogen sulfide
gas.
Oil Fingerprinting: A method that
identifies sources of oil and allows
spills to be traced to their source.
Oil Spill: An accidental or intentional
discharge of oil which reaches bodies of
water. Can be controlled by chemical
dispersion, combustion, mechanical
containment, and/or adsorption. Spills
from tanks and pipelines can also
occur away from water bodies, contam-
inating the soil, getting into sewer
systems and threatening underground
water sources.
Oligotrophic Lakes: Deep clear lakes
with few nutrients, little organic mat-
ter and a high dissolved-oxygen level.
One-hit Model: A mathematical model
based on the biological theory that a
single "hit" of some minimum critical
amount of a carcinogen at a cellular
target such as DNA can start an irre-
versible series events leading to a
tumor.
On-Scene Coordinator (OSO The pre-
designated EPA, Coast Guard, or De-
partment of Defense official who coor-
dinates and directs Superfund removal
actions or Clean Water Act oil-or haz-
ardous-spill response actions.
On-Site Facility: A hazardous waste
treatment, storage or disposal area
that is located on the generating site.
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28
Onboard Controls: Devices placed on
vehicles to capture gasoline vapor dur-
ing refueling and route it to the en-
gines when the vehicle is starting so
that it can be efficiently burned.
Opacity: The amount of light obscured
by particulate pollution in the air;
clear window glass has zero opacity, a
brick wall is 100 percent opaque. Opac-
ity is an indicator of changes in perfor-
mance of particulate control systems.
Open Burning: Uncontrolled fire's in an
open dump.
Open Dump: An uncovered site used
for disposal of waste without environ-
mental controls. (See: dump.)
Operable Unit: Term for each of a
number of separate activities under-
taken as part of a Superfund site
cleanup. A typical operable unit would
be removal of drums and tanks from
the surface of a site. ,
Operating Conditions: Conditions spec-
ified in a RCRA permit that dictate
how an incinerator must operate as it
burns different waste types. A trial
burn is used to identify operating con-
ditions needed to meet specified per-
formance standards.
Operation And Maintenance: 1. Activi-
ties conducted after a Superfund site
action is completed to ensure that the
action is effective. 2. Actions taken
after construction to assure that facili-
ties constructed to treat waste water
will be properly operated and main-
tained to achieve normative efficiency
levels and prescribed effluent limita-
tions in an optimum manner. 3. On-
going asbestos management plan in a
school or other public building, includ-
ing regular inspections, various meth-
ods of maintaining asbestos in place,
and removal when necessary.
Optimal Corrosion Control Treatment
An erosion control treatment that
minimizes the lead and copper concen-
trations at users' taps while also insur-
ing that the treatment does not cause
the water system to violate any nation-
al primary drinking water regulations.
Oral Tenacity: Ability of a pesticide to
cause injury when ingested.
Organic 1. Referring to or derived
from living organisms. 2. In chemistry,
any compound containing carbon.
Organic
Ani-
mal or plant-produced substances
containing mainly carbon, hydrogen,
nitrogen, and oxygen.
Organic Matter: Carbonaceous waste
contained in plant or animal matter
and originating from domestic or in-
dustrial sources.
Organism: Any form of animal or plant
life.
Organophosphates: Pesticides that con-
tain phosphorus; short-lived, but some
can be toxic when first applied.
Organotins: Chemical compounds used
in anti-foulant paints to protect the
hulls of boats and ships, buoys, and
pilings from marine organisms such as
barnacles.
Original AHERA Inspection/Original
Inspection/Inspection: Examination of
school buildings arranged by Local
Education Agencies to identify asbesto-
s-containing-materials, evaluate their
condition, take samples of materials
suspected to contain asbestos; per-
formed by EPA-accredited inspectors
Original Generation Point Where
regulated medical or other material
first becomes waste.
Osmosis: The passage of a liquid from
a weak solution to a more concentrated
solution across a semipermeable mem-
brane that allows passage of the sol-
vent (water) but not the dissolved
solids.
Outfall: The place where effluent is
discharged into receiving waters.
Overburden: Rock and soil cleared
away before mining.
Overdraft: The pumping of water from
a groundwater basin or aquifer in
excess of the supply flowing into the
basin; results in a depletion or "min-
ing" of the groundwater in the basin.
(See: groundwater mining)
Overfire Air: Air forced into the top of
an incinerator or boiler to fan the
flames.
Overflow Rate: One of the guidelines
for design of the settling tanks and
clarifers in a treatment plant; used by
plant operators to determine if tanks
and clarifiers are over-or under-used.
Overland Flow: A land application
technique that cleanses waste water by
allowing it to flow over a sloped sur-
face. As the water flows over the sur-
face, contaminants are absorbed and
the water is collected at the bottom of
the slope for reuse.
Oversized Regulated Medical Waste:
Medical waste that is too large for
plastic bags or standard containers.
Overturn: One complete cycle of top to
bottom mixing of previously stratified
water masses. This phenomenon may
occur in spring or fall, or after storms,
and results in uniformity of chemical
and physical properties of water at all
depths.
Oxidant A substance containing oxy-
gen that reacts chemically in air to
produce a new substance; the primary
ingredient of photochemical smog.
Oxidation: The addition of oxygen that
breaks down organic waste or chemi-
cals such as cyanides, phenols, and
organic sulfur compounds in sewage by
bacterial and chemical means.
Oxidation Pond: A man-made body of
water in which waste is consumed by
bacteria, used most frequently with
other waste-treatment processes; a
sewage lagoon.
Oxidation-Reduction Potential: The
electric potential required to transfer
electrons from one compound or ele-
ment (the oxidant) to another com-
pound,(the reductant); used as a quali-
tative measure of the state of oxidation
in water treatment systems.
Oxygenated Fuels: Gasoline which has
been blended with alcohols or ethers
that contain oxygen in order to reduce
carbon monoxide and other emissions.
Oxygenated Solvent An organic sol-
vent containing oxygen as part of the
molecular structure. Alcohols and keto-
nes are oxygenated compounds often
used as paint solvents.
Ozone (Oj): Found in two layers of the
atmosphere, the stratosphere and the
troposphere. In the stratosphere (the
atmospheric layer 7 to 10 miles or
more above the earth's surface) ozone
is a natural form of oxygen that pro-
vides a protective layer shielding the
earth from ultraviolet radiation. In the
troposphere (the layer extending up 7
to 10 miles from the earth's surface),
ozone is a chemical oxidant and major
component of photochemical smog. It
can seriously impair the respiratory
system and is one of the most wide-
spread of all the criteria pollutants for
which the Clean Air Act required EPA
to set standards. Ozone in the tropo-
sphere is produced through complex
chemical reactions of nitrogen oxides,
which are among the primary pollut-
ants emitted by combustion sources;
hydrocarbons, released into the atmo-
sphere through the combustion, han-
dling and processing of petroleum
products; and sunlight.
Ozonation/Ozonator: Application of
ozone to water for disinfection or for
taste and odor control. The ozonator is
the device that does this.
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29
Ozone Depletion: Destruction of the st-
ratospheric ozone layer which shields
the' earth from ultraviolet radiation
harmful to life. This destruction of
ozone is caused by the breakdown of
certain chlorine and/or-bromJae con-
taining compounds (chlorofluoro-
carbons or halons), which break down
when they reach the stratosphere and
then catalytically destroy ozone mole-
cules.
Ozone Hole:Thinning break in the stra-
tospheric ozone layer. Designation of
amount of such depletion as an "ozone
hole" is made when detected amount of
depletion exceeds fifty percent. Sea-
sonal ozone holes have been observed
over both the Antarctic region and the
Arctic region and part of Canada and
the extreme northeastern United
States. .
Ozone Layer The protective layer in
the atmosphere, about 15 miles above
the ground, that absorbs some of the
sun's ultraviolet rays, thereby reducing
the amount of potentially harmful
radiation that reaches the earth's sur-
face.
Packaging: The assembly of one or
more containers and any other compo-
nents necessary to assure TniniTmiiti
compliance with a program's storage
and shipment packaging requirements.
Also, the containers, etc., involved.
Packed Bed Scrubber An air pollution
control device in which emissions pass
through alkaline water to neutralize
hydrogen chloride gas.
Packed Tower A pollution control
device that forces dirty air through a
tower packed with crushed rock or
wood chips while liquid is sprayed over
the packing material. The pollutants in
the air stream either dissolve or chemi-
cally react with the liquid.
Palatable Water Water, at a desirable
temperature, that is free from objec-
tionable tastes, odors, colors, and tur-
bidity.
Pandemic: Widespread throughout an
area, nation or the world.
Parameter A variable, measurable
property whose value is a determinant
of die characteristics of a system; e.g.,
temperature, pressure, and density are
parameters of the atmosphere.
Paraquat: A standard herbicide used to
kill various types of crops, including
marijuana.
Part A Permit, Part B Permit: (See: In-
terim Permit Status.)
Parahall Flume: Device used to mea-
sure the flow of water in an open chan-
nel.
Particle Count Results of a microscop-
ic examination of treated water with a
special "particle counter" that classifies
suspended particles by number and
size.
Particulate Loading: The mass of part-
iculates per unit volume of air or wa-
ter.
Participation Rate: Portion of popula-
tion participating in a recycling pro-
grani.
Particulates: 1. Fine liquid or solid
particles such as dust, smoke, mist,
fumes, or smog, found in air or emis-
sions. 2. Very small solids suspended
in water,; they can vary in size, shape,
density and electrical charge and can
be gathered together by coagulation
and fiocculation.
Partition Coefficient: Measure of the
sorption phenomenon, whereby a pesti-
cide is divided between the soil and
water phase; also referred to as ad-
sorption partition coefficient.
Parts Per Billion (ppbyParts Per Mil-
lion (ppm): Units commonly used to
express contamination ratios, as in
establishing the maximum permissible
amount, of a contaminant in water,
.land, or air.
Pathogen*: Microorganisms that can
cause disease in other organisms or in
humans, animals and plants (e.g.,
bacteria, viruses, or parasites) found in
sewage, in runoff from farms or rural
areas populated with domestic and
wild animals, and in water used for
swimming. Fish and shellfish contami-
nated by pathogens, or the contam-
inated water itself, can cause serious
illness.
Peak Electricity Demand: The maxi-
mum electricity used to meet the cool-
ing load of a building or buildings in a
given area.
Peak Levels: Levels of airborne pol-
lutant contaminants much higher than
average or occurring for short periods
of time in response to sudden releases.
Percent Saturatiuon: The amount of a
substance that is dissolved in a solu-
tion compared to the amount that
could be dissolved in it.
Perched Water Zone of unpressurized
water held above the water table by
impermeable rock or sediment.
Percolating Water Water that passes
through rocks or soil under the force of
gravity.
Percolation: 1. The movement of water
downward and radially through subur-
face soil layers, usually continuing
downward to ground water. Can also
involve upward movement of water. 2.
Slow seepage of water through a filter.
Performance Data (for incinerators):
Information collected, during a trial
burn, on concentrations of designated
organic compounds and pollutants
found in incinerator emissions. Data
analysis must show that the incinera-
tor meets performance standards un-
der operating conditions specified in
the RCRA permit. (See: trial burn; per-
formance standards.)
Performance Standards: 1. Regulatory
requirements limiting the concentra-
tions of designated organic compounds,
particulate matter, and hydrogen chlo-
ride in emissions from incinerators. 2.
Operating standards established by
EPA for various permitted pollution
control systems, asbestos inspections,
and various program operations and
maintenance requirements.
Periphyton; Microscopic underwater
plants and animals that are firmly at-
tached solid surfaces such as rocks,.
logs, pilings, and other structures.
Permeability: The rate at which liquids
pass through soil or other materials in
a specified direction.
Permissible Dose: The dose of a chemi-
cal that may be received by an individ-
ual without the expectation of a
sinificantly harmful result.
Permit: An authorization, license, or
equivalent control document issued by
EPA or an approved state agency to
implement the requirements of an
environmental regulation; e.g., a per-
mit to operate a wastewater treatment
plant or to operate a facility that may
generate harmful emissions.
Persistence: Refers to the length of
time a compound stays in the environ-
ment, once introduced. A compound
may persist for less than a second or
indefinitely.
Persistent Pesticides: Pesticides that
do not break down chemically or
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30
break down very slowly and remain in
the environment after a growing sea-
son.
Personal Air Samples: Air samples
taken with a pump directly attached to
the worker with the collecting filter
and cassette placed in the worker's
breathing zone (required under OSHA
asbestos standards and EPA worker
protection rule).
Pest: An insect, rodent, nematode, fun-
gus, weed or other form of terrestrial
or aquatic plant or animal life that is
injurious to health or the environment.
Pesticide: Substances or mixture there-
of intended for preventing, destroying,
repelling, or mitigating any pest. Also,
any substance or mixture intended for
use as a plant regulator, defoliant, or
desiccant.
Pesticide Tolerance: The amount of
pesticide residue allowed by law to
remain in or on a harvested crop. EPA
sets these levels well below the point
where the compounds might be harm-
ful to consumers.
Petroleum Derivatives: Chemicals
formed when gasoline breaks down in
contact with ground water.
pH; An expression of the intensity of
the basic or acid condition of a, liquid;
may range from 0 to 14, where 0 is the
most acid and 7 is neutral. Natural
waters usually have a pH between 6.5
and 8.5.
Pharmakinetica: The dynamic behavior
of chemicals inside biological systems,
including uptake, distribution, metab-
olism, and excretion.
Phenolphthalein Alkalinity The alka-
linity in a water sample measured by
the amount of standard acid needed to
lower thge pH to a level of 8.3 as indi-
cated by the change of color of the
phenolphthalein from pink to clear.
Phenols: Organic compounds that are
byproducts of petroleum refining, tan-
ning, and textile, dye, and resin manu-
facturing. Low concentrations cause
taste and odor problems in water;
higher concentrations can kill aquatic
life and humans.
Phosphates: Certain chemical com-
pounds containing phosphorus.
Phosphogypsum Piles (stacks): Princi-
pal byproduct generated in production
of phosphoric acid from phosphate
rock. These piles may generate radio-
active radon gas.
Phosphorous Plantar Facilities using
electric furnaces to produce elemental
phosphorous for commercial use, such
as high grade phosphoric acid, phos-
phate-based detergent, and organic
chemicals use. .
Phosphorus: An essential chemical food
element that can contribute to the
eutrophication of lakes and other wa-
ter bodies. Increased phosphorus levels
result from discharge of phosp-
horus-containing materials into surface
waters.
Photochemical Oxidants: Air pollutants
formed by the action of sunlight on ox-
ides of nitrogen and hydrocarbons.
Photochemical Smog: Air pollution
caused by chemical reactions of various
pollutants emitted from different
sources.
Photosynthesis: The manufacture by
plants of carbohydrates and oxygen
from carbon dioxide mediated by chlo-
rophyll in the presence if sunlight.
Physical and Chemical Treatment: Pro-
cesses generally used in large-scale
wastewater treatment facilities. Physi-
cal processes may include air-stripping
or filtration. Chemical treatment in-
cludes coagulation, chlorination, or
ozonation. The term can also refer to
treatment of toxic materials in surface
and ground waters, oil spills, and some
methods of dealing with hazardous
materials on or in the ground.
Phytoplankton: That portion of the
plankton community comprised of tiny
plants, e.g., algae, diatoms.
Phytotozie Harmful to plants.
Picocuries Per Liter pCVL>. A unit of
measure for levels of radon gas.
Pilot Tests: Testing a cleanup tech-
nology under actual site conditions to
identify potential problems prior to
full-scale implementation.
Plankton: Tiny plants and animals
that live in water.
Plasma-arc Reactor. An incinerator
that operates at extremely high tem-
peratures; treats highly toxic wastes
that do not burn easily.
Plasmid: A circular piece of DNA that
exists apart from the chromosome and
replicates independently of it. Bacterial
plasmids carry information that ren-
ders the bacteria resistant to antibi-
otics. Plasmids are'often used in genet-
ic engineering to carry desired genes
into organisms.
Plastics: Non-metallic chemoreactive
compounds molded into rigid or pliable
construction materials, fabrics, etc.
Plate Tower Scrubber An air pollution
control device that neutralizes hydro-
gen chloride gas by bubbling alkaline
water through holes in a series of
metal plates.
Plug Flow: Type of flow that occurs in
tanks, basins, or reactors when a slug
of water moves through without ever
dispersing or mixing with the rest of
the water flowing through.
Plugging: Act or process of stopping
the flow of water, oil, or gas into or out
of a formation through a borehole or
well penetrating that formation.
Plume: 1. A visible or measurable dis-
charge of a contaminant from a given
point of origin. Can be visible or ther-
mal in water, or visible in the air as,
for example, a plume of smoke. 2 The
area of radiation leaking from a dam-
aged reactor. 3. Area downwind within
which a release could be dangerous for
those exposed to leaking fumes.
Plutonium: A radioactive metallic ele-
ment chemically similar to uranium.
PM-10: A standard for measuring the
amount of solid or liquid matter sus-
pended in the atmosphere, i.e. the
'amount of particulate matter over 10
micrometers in diameter; smaller PM-
10 particles penetrate to the deeper
portions of the lung, affecting sensitive
population groups such as children and
individuals with respiratory ailments.
Point of Disinfectant Application: The
point where disinfectant is applied and
water downstream of that point is not
subject to recontamination by surface
water runoff.
Point-of-Entry Treatment Device: A
treatment device 'applied to the drink-
ing water entering a house or building
to reduce the contaminants in the
water distributed throughout the house
or building.
Point-of Use Treatment Device: Treat-
ment device applied to a single tap to
reduce contaminants in the drinking
water at the one faucet
Point Source: A stationary location or
fixed facility from which pollutants are
discharged; any single identifiable
source of pollution, e.g., a pipe, ditch,
ship, ore pit, factory smokestack.
Pollen: The fertilizing element of flow-
ering plants; background air pollutant.
Pollutant: Generally, any substance in-
troduced into the environment that ad-
versely affects the usefulness of a re-
source.
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31
Pollution Prevention; The active pro-
cess of identifying areas, processes,
and activities which create excessive
waste byproducts or pollutants for the
purpose of substitution, alteration, or
elimination of the process to prevent
waste and pollutant generation.
Pollutant Standard Index (PSD: Mea-
sure of adverse health effects of air
pollution levels in major cities.
Pollution: Generally, the presence of
matter or energy whose nature, loca-
tion, or quantity produces undesired
environmental effects. Under the Clean
Water Act, for example, the term is
defined as the manmade or man-in-
duced alteration of the physical, biolog-
ical, chemical, and radiological integ-
rity of water. ,
Polonium: A radioactive element that
occurs in pitchblende and other urani-
um-containing ores.
Polyelectrolytea: Synthetic chemicals
that help solids to clump during sew-
age treatment.
Polymer: Basic molecular ingredients
in plastic.
Polyvinyl Chloride (PVC): A tough,
environmentally indestructible plastic
that releases hydrochloric acid when
burned.
Population: A group of interbreeding
organisms occupying a particular
space; the number of humans or other
living creatures in a designated area.
Population at Riak: A population sub-
group that is more likely to be exposed
to a pollutant, or is more sensitive to
the pollutant, than is the general popu-
lation.
Porosity. Degree to which noil, gravel,
sediment, or rock is permeated with
pores or cavities through which water
or air «•*" move.
Poetchlorination: Addition of chlorine
to plant effluent for disinfectant pur-
poses after the effluent has been treat-
ed.
Poet-Closure: Time period following the
shutdown of a waste management or
manufacturing facility; for monitoring
purposes, often considered to, be 30
years.
Post-Consumer Recycling: Reuse of
materials generated from residential
and consumer waste, e.g.. converting
wastepaper from offices into corrugat-
ed boxes or newsprint.
Potable Water Water that is safe for
drinking and cooking.
Potentially Responsible Party (PRP>.
Any individual or company-including
owners, operators, transporters or
generators-potentially responsible for,
or contributing to a spill or other con-
tamination at a Superfund site. When-
ever possible, through administrative
and legal actions, GPA requires PRPs
to clean up hazardous sites they have
contaminated.
Potentiation: The ability of one chemi-
cal to increase the effect of another
chemical.
Prechlorination: The addition of chlo-
rine at the headworks of a treatment
plant prior to other treatment process-
es. Done mainly for disinfection and
control of tastes, odors, and aquatic
growths, and to aid in coagulation and
settling,
Precipitate: A solid that separates from
a solution.
Precipitation: Removal of hazardous
solids from liquid waste to permit safe
disposal; removal of particles from
airborne emissions.
Precipitator. Pollution control device
that collects particles from an air
stream.
Precursor: In photochemistry, a com-
pound antecedent to a volatile organic
compound (VOC). Precursors react in
sunlight to form ozone or other photo-
chemical oxidants.
Preliminary Assessment: The process
of collecting and reviewing available
information about a known or suspect-
ed waste site or release.
Prescriptive: Water rights which are
acquired by diverting water and put-
ting it to use in accordance with speci-
fied procedures, e.g., filing a request
with a state agency to use unused
water in a stream, river, or lake..
Pressure Sewers: A system of pipes in
which water, wastewater, or other
liquid is pumped to a higher elevation.
Pretreatinent: Processes used to re-
duce, eliminate, or alter the nature of
wastewater pollutants from non-dom-
estic sources before they are dis-
charged into publicly owned treatment
works (POTWs).
Prevalent Level Samples: Air samples
taken under normal conditions (also
known as ambient background sam-
ples).
Prevalent Levels: Levels of airborne
contaminant occurring under normal
conditions.
Prevention of Significant Deterioration
(PSD): EPA program in which state
and/or federal permits are required in
order to restrict emissions from new or
modified sources in places where air
quality already meets or exceeds pri-
mary and secondary ambient air quali-
ty standards.
Primacy: Having the primary responsi-
bility for administering and enforcing
regulations.
Primary Drinking Water Regulation:
Applies, to public water systems and
specifies a contaminant level, which, in
the judgment of the EPA Administra-
tor, will not adversely affect human
health.
Primary Standards: National ambient
air quality standards designed to pro-
. tect human health with an adequate
margin for safety. (See National Ambi-
ent Air Quality Standards, secondary
standards)
Primary Waste Treatment: First steps
in wastewater treatment; screens and
sedimentation tanks are used to re-
move most materials that float or will
settle. Primary treatment removes
about 30 percent of carbonaceous bio-
chemical oxygen demand from domes-
tic sewage.
Principal Organic Hazardous Constitu-
ents (POHCa): Hazardous compounds
monitored during an incinerator's trial
burn, selected for high concentration in
the waste feed and difficulty of com-
bustion.
Prior Appropriation: A doctrine of
water law that allocates the rights to
use water on a first-come, first-served
basis.
Probability of Detection: The likeli-
hood, expressed as a percentage, that
a test method will correctly identify a
leaking tank.
Process Variable: A physical or chemi-
cal quantity which is usually measured
and controlled in the operation of a
water treatment plant or industrial
plant.
Process Verification: Verifying that
process raw materials, water usage,
waste treatment processes, production
rate and other facts relative to quanti-
ty and quality of pollutants contained
in. discharges are substantially de-
scribed in the permit application and
the issued permit.
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32
Process Waste-water Any water that
comes into contact with any raw mate-
rial, product, byproduct, or waste.
Process Weight: Total weight of all
materials, including fuel, used in a ma-
nufacturing process; used to calculate
the allowable particulate emission
rate.
Product Level: The level of a product
in a storage tank.
, Product Water Water that has passed
through a water treatment plant and
is ready to be delivered to consumers.
Products of Incomplete Combustion
(PICs): Organic compounds formed by
combustion. Usually generated in
small amounts and sometimes toxic,
PICs are heat-altered versions of the
original material fed into the incin-
erator (e.g., charcoal is a P.C. from
burning wood).
Propellent: Liquid in a self-pressurized
pesticide product that expels the active
ingredient from its container.
Proposed Plan: A plan for a site clean-
up that is available to the public for
comment.
Proteins: Complex nitrogenous organic
compounds of high molecular weight
made of amino acids; essential for
growth and repair of animal tissue.
Many, but not all, proteins are en-
zymes.
Protocol: A series of formal steps for
conducting a test.
Protoplast: A membrane-bound cell
from which the outer wall has been
partially or completely removed. The
term often is applied to plant cells.
Protozoa: One-celled animala that are
larger and more complex than bacteria.
May cause disease.
Public Comment Period: The time al-
lowed for the public to express its
views and concerns regarding an ac-
tion by EPA (e.g., a Federal Register
Notice of proposed rule-making, a
public notice of a draft permit, or a No-
tice of Intent to Deny).
Public Hearing: A formal meeting at
which EPA officials hear the public's
views and concerns about an EPA
action or proposal. EPA is required to
consider such comments when evalu-
ating its actions. Public hearings must
be held upon request during the public
comment period.
Public Notice: 1. Notification by EPA
informing the public of Agency actions
such as the issuance of a draft permit
or scheduling of a hearing. EPA is
required to ensure proper public notice,
including publication in newspapers
and broadcast media.- 2. In the safe
drinking water program, water suppli-
ers are required to publish and broad-
cast notices when pollution problems
are discovered.
Public Water System: A system that
provides piped water for human con-
sumption to at least 15 service con-
nections or regularly serves 25 indi-
viduals.
Publicly Owned Treatment Works: A
waste-treatment works owned by a
state, unit of local government, or
Indian tribe, usually designed to treat
domestic waste waters. .
Pumping Station: Mechanical devices
installed in sewer or. water systems or
other liquid-carrying pipelines to move
the liquids to a higher level.
Putrefaction: Biological decomposition
of organic matter; associated with
anaerobic conditions.
Putreacible: Able to rot quickly enough
to cause odors and attract flies.
Pyrolyms: Decomposition of a chemical
by extreme heat.
Quality Assurance/Quality Control: A
system of procedures, checks, audits,
and corrective actions to ensure that
all EPA research design and perfor-
mance, environmental monitoring and
sampling, and other technical and
reporting activities are of the highest
achievable quality.
Quench Tank A water-filled tank
used to cool incinerator residues or hot
materials during industrial processes.
Radiation: Transmission of energy
though space or any medium. Also
known as radiant energy.
Radiation Standards: Regulations that
set maximum exposure limits for pro-
tection of the public from radioactive
materials.
Radio Frequency Radiation: (See Non-
ionizing Radiation.)
Radioactive Decay: Spontaneous
change in an atom by emission of
charged particles and/or gamma rays;
also known as radioactive disintegra-
tion and radioactivity.
Radioactive Substances: Substances
that emit ionizing radiation.
Radioisotopes: Chemical variants of an
element with potentially oncogenic,
teratogenic, and mutagenic effects on
the human body.
Radionuclide: Radioactive particle,
man-made or natural, with a. distinct
atomic weight number. Can have a
long life as soil or water pollutants.
Radius of Vulnerability Zone: The
maximum distance from the point of
release of a hazardous substance in
which the airborne concentration could
reach the level of concern under spec-
ified weather conditions.
Radon: A colorless naturally occur-
ring, radioactive, inert gas formed by
radioactive decay of radium atoms in
soil or rocks,
Radon Daughters/Radon Progeny:
Short-lived radioactive decay products
of radon that decay into longer-lived
lead isotopes that can attach them-
selves to airborne dust and other parti-
cles and, if inhaled, damage the linings
of the lungs.
Radon Decay Products: A term used to
refer collectively to the immediate
products of the radon decay chain.
These include Po-218, Pb-214, Bi-214,
and Po-214, which have an average
combined half-life of about 30 minutes.
Rasp: A machine that grinds waste
into a manageable material and helps
prevent odor.
Raw Sewage: Untreated wastewater
and its contents.
Raw Water Intake water prior to any
treatment or use.
Reaeration: Introduction of air into the
lower layers of a reservoir. As the air
bubbles form and rise through the wa-
ter, the oxygen dissolves into the water
and replenishes the dissolved oxygen.
The rising bubbles also cause the lower
waters to rise to the surface where
they take on oxygen from the atmosph-
ere.
Reasonable Further Progress: Annual
incremental reductions in air pollutant
emissions as reflected in a State Imple-
mentation Plan that EPA deems suffi-
cient to provide for the attainment of
the applicable national ambient air
quality standards by the statutory dea-
dline.
Reasonable Maximum Exposure: The
maTJTrmm exposure reasonably expect-
ed to occur in a population.
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33
Reasonably Available Control Mea-
sures (RACM): A broadly defined term
referring to technological and other
measures for pollution control.
Reasonably Available Control Technol-
ogy (RACT): Control technology that is
reasonably available and both techno-
logically and economically feasible.
Usually applied to existing sources in
nonattainment areas; in most cases is
less stringent than new source perfor-
mance standards.
Recarbonization: Process in which
carbon dioxide is bubbled into water
being treated to lower the pH.
Receiving Waters: A river, lake, ocean,
stream, or other watercourse into
which wastewater or treated effluent is
discharged.
Recharge: The process by which water
is added to a zone of saturation, usual-
ly by percolation from the soil surface,
e.g., the recharge of an aquifer.
Recharge Area: A land area in which
water reaches the zone of saturation
from surface infiltration, e.g., where
rainwater soaks through the earth to
reach an aquifer.
Recharge Rate: The quantity of water
per unit of time that replenishes or
refills an aquifer.
Reclamation: (In recycling) Restoration
of materials found in the waste stream
to a beneficial use which may be for
purposes other than the original use.
Recombinant Bacteria: A microorgan-
ism whose genetic makeup has been
altered by deliberate introduction of
new genetic elements. The offspring of
these altered bacteria also contain
these new genetic elements:, i.e. they
"breed true."
Recombinant DNA: The new DNA that
is formed by combining pieces of DNA
from different organisms or cells.
Level (RMCL): The maximum level of
a contaminant in drinking water at
which no known or anticipated adverse
affect on human health would occur,
and that includes an adequate margin
of safety. Recommended levels are
nonenforceable health goals. (See:
maximum contaminant level.)
Reconstructed Source: Facility in
which components are replaced to such
an extent that the fixed capital cost of
the new components exceed 50 percent
of the capital cost of constructing a
comparable brand-new facility. New-
source performance standards may be
applied to sources reconstructed after
the proposal of the standard if it is
technologically and economically feasi-
ble to meet the standard.
Record of Decision (ROD): A public
document that explains which cleanup
alternative(s) will be used at National
Priorities List sites where, under
CERCLA, Trust Funds pay for the
cleanup.
Recovery Rate: Percentage of usable
recycled materials that have been re-
moved from the total amount of mu-
nicipal solid waste generated in a spe-
cific area or by a specific business.
Recycle/Reuse: Minimizing waste gen-
eration by recovering and reprocessing
usable products that might otherwise
become waste (.i.e. recycling of alu-
minum cans, paper, and bottles, etc.).
Red Bag Waste: (See: infectious waste.)
Red Border: An EPA document under-
going review before being submitted
for final management decision-making.
"Red Tide: A proliferation of a marine
plankton toxic often fatal to fish, per-
haps stimulated by the addition of
nutrients. A tide can be red, green, or
brown, depending on the coloration of
the plankton.
Reduction: The addition of hydrogen,
removal of oxygen, or addition of elect-
rons to an element or compound.
Reentry Interval: The period of time
immediately following the application
of a pesticide during which unprotected
workers should not enter a field.
Reference Dose (RfD): The concentra-
tion of a chemical known to cause
health problems; also referred to as the
ADI, or acceptable daily intake.
Reformulated Gasoline: Gasoline with
a different composition from conven-
tional gasoline (e.g., lower aromatics
content) that cuts air pollutants.
Roftioling Emissions: Emissions re-
leased during vehicle refueling.
Refuse Reclamation: Conversion of
solid waste into useful products, e.g.,
composting organic wastes to make soil
conditioners or separating aluminum
and other metals for recycling.
Refuse: (See: solid waste.)
. Regeneration: Manipulation of cells to
cause them to develop into whole
plants.
Regional Response Team (RRT): Repre-
sentatives of federal, local, and state
agencies who may assist in coordina-
tion of activities at the request of the
On-Scene Coordinator before and dur-
ing a- significant pollution incident
such as an oil spill, major chemical
release, or a Superfund response.
Registrant: Any manufacturer or for-
mula tor who obtains registration for a
pesticide active ingredient or product.
Registration: Formal listing with EPA
of a new pesticide before it can be sold
or distributed. Under the Federal In-
secticide, Fungicide, and Rodenticide
Act. EPA is responsible for registration
(pre-market licensing) of pesticides on
the basis of data demonstrating no un-
reasonable adverse effects on human
health or the environment when ap-
plied according to approved label direc-
tions.
Registration Standards: Published
documents which include summary re-
views of the data available on a pest-
icide's active ingredient, data gaps, and
the -Agency's existing regulatory posi-
tion on the pesticide.
Regulated Asbestos-Containing Materi-
al (RACM>. Friable asbestos material
or nonfriable ACM that will be or has
been subjected to sanding, grinding,
cutting, or abrading or has crumbled,
or been pulverized or reduced to pow-
der in the course of demolition or ren-
ovation operations.
Regulated Medical Waste: Under the
Medical Waste Tracking Act of 1988,
any solid waste generated in the diag-
nosis, treatment, or immunization of
human beings or animals, in research
pertaining thereto, or in the production
or testing of biologicals. Included are
cultures and stocks of infectious
agents; human blood and blood prod-
ucts; human pathological body wastes
from surgery and autopsy; contaminat-
ed animal carcasses from medical re-
search; waste from patients with com-
municable diseases; and all used sharp
implements, such as needles and scal-
pels, etc., and certain unused sharps.
(See; treated medical waste; untreated
medical waste; destroyed medical
waste.)
Release: Any spilling, leaking, pump-
ing, pouring, emitting, emptying, dis-
charging, injecting, escaping, leaching,
dumping, or disposing into the environ-
ment of a hazardous or toxic chemical
or extremely hazardous substance.
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34
Remedial Action (RA): The actual cons-
truction or implementation phase of a
Super-fund site cleanup that follows
remedial design.
Remedial Design: A phase of remedial
action that follows the remedial inves-
tigation/feasibility study and includes
development of engineering drawings
and specifications for a site cleanup.
Remedial Investigation: An in-depth
study designed to gather data needed
to determine the nature and extent of
contamination at a Superfund site,
establish site cleanup criteria, identify
preliminary alternatives for remedial
action, and support technical and cost
analyses of alternatives. The remedial
investigation is usually done with the
feasibility study. Together they are
usually referred to as the "RI/FS".
Remedial Project Manager (RPM): The
EPA or state official responsible for
overseeing on-site remedial action.
Remedial Response: Long-term action
that stops or substantially reduces a
release or threat of a release of hazard-
ous substances that is serious but not
an immediate threat to public health.
Remediation: 1. Cleanup or other
methods used to remove or contain a
toxic spill or hazardous materials from
a Superfund site; 2. for the Asbestos
Hazard Emergency Response program,
abatement methods including evalu-
ation, repair, enclosure, encapsulation,
or removal of greater than 3 linear feet
or square feet of asbestos-containing
materials from a building.
Remote Sensing: The collection and
interpretation of information about an
object without physical contact with
the object; e.g., satellite imaging and
aerial photograph.
Removal Action: Short-term immediate
actions taken to address releases of
hazardous substances that require
expedited response. (See: cleanup.)
Repeat Compliance Period: Any subse-
quent compliance period after the
initial one.
Reportable Quantity (RQ): Quantity of
a hazardous substance that triggers re-
ports under CERCLA. If a substance
exceeds its RQ, the release must be
reported to the National Response
Center, the SERC, and ^immunity
emergency coordinators for areas likely
to be affected.
Repowering: Rebuilding and replacing
major components of a power plant
instead of building a new one.
Representative Sample: A portion of
material or water that is as nearly
identifies! in content and consistency
as possible to that in'the larger body of
material or water being sampled.
Reregistration: The reevaluation and
relicensing of existing pesticides origi-
nally registered prior to current scien-
tific and regulatory standards. EPA
reregisters pesticides through its Reg-
istration Standards Program. .
Reserve Capacity: Extra treatment
capacity built into solid waste and
wastewater treatment plants and in-
terceptor sewers to accommodate flow
increases due to future population
growth.
Reservoir: Any natural or artificial
holding area used to store, regulate, or
control water.
Residual: Amount of a pollutant re-
maining in the environment after a
natural or technological process has
taken place, e.g., the sludge remaining
after initial wastewater treatment, or
particulates remaining in air after it
passes through a scrubbing or other
process.
Residual Risk: The extent of health
risk from air pollutants remaining
after application of the Maximum A-
chievable Control Technology (MACT).
Residue: The dry solids remaining
after the evaporation of a sample of
water or sludge.
Resistance: For plants and animals,
the ability to withstand poor environ-
mental conditions or attacks by chemi-
cals or disease. May be inborn or ac-
quired.
Reaource Recovery: The process of
obtaining matter or energy from mate-
rials formerly discarded.
Response Action: 1. Generic term for
actions taken in response to actual or
potential health-threatening environ-
mental events such as spills, sudden
releases, and asbestos abate-
menl/manageinent problems; 2. A
CERCLA-authorized action involving
either a short-term removal action or a
long-term removal response. This may
include but is not limited to: removing
hazardous materials from a site to an
EPA-approved hazardous waste facility
for treatment, containment or treating
the waste on-site, identifying and re-
moving the sources of ground-water
contamination and halting further
migration of contaminants; 3. Any of
the following actions taken in school
buildings in response to AHERA to
reduce the risk of exposure to asbestos:
removal, encapsulation, enclosure,
repair, and operations and ' mainte-
nance. (See: cleanup)
Responsiveness Summary: A summary
of oral and/or written public comments
received by EPA during a comment
period on key EPA documents, and
EPA's response to those comments.
Restoration: Measures taken to return
a site to pre-violation conditions.
Restricted Use: A pesticide may be
classified (under FIFRA regulations)
for restricted use if the it requires
special handling because of its toxicity,
and, if so, it may be applied only by
trained, certified applicators or those
under their direct supervision.
Restriction Enzymes: Enzymes that
recognize specific regions of a long
DNA molecule and cut it at those
points.
Retrofit: Addition of a pollution control
device on an existing facility without
making major changes to the generat-
ing plant.
Reuse: Using a product or component
of municipal solid waste in its original
form more than once, e.g., refilling a
glass bottle that has been returned or
using a coffee can to hold nuts and
bolts.
Reverse Osmosis: A treatment process
used in water systems by adding pres-
sure to force water through a semi-
permeable membrane. Reverse osmosis
removes most drinking water contami-
nants. Also used in wastewater treat-
ment. Large-scale reverse osmosis
plants are being developed.
Reversible Effect: An effect which is
not permanent; especially adverse
effects which diminish when exposure
to a toxic chemical stops.
Ribonucleic Acid (RNA): A molecule
that carries the genetic message from
DNA to a cellular protein-producing
mechanisms.
Rill: A small channel eroded into the
soil by surface runoff; can be easily
smoothed out or oblitrated by normal
tillage.
Ringlemann Chart: A series of shaded
illustrations used to measure the opac-
ity of air pollution emissions, ranging
from light grey through black; used to
set and enforce emissions standards.
Riparian Habitat: Areas adjacent to
rivers and streams with a high densi-
ty, diversity, and productivity of plant
and animal species relative to nearby
uplands.
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35
Riparian Rights: Entitlement of a land
owner to certain uses of water on or
bordering his property, including the
right to prevent diversion or misuse of
upstream waters. Generally a matter
of state law.
Risk: A measure of the probability that
damage to life, health, property, and/or
the environment will occur as a result
of a given hazard.
Risk Assessment; Qualitative and
quantitative evaluation of the risk
posed to human health and/or the
environment by the actual or potential
presence and/or use of specific pollut-
ants.
Risk-baaed Targeting: The direction of
resources to those areas that have
been identified as having the highest
potential or actual adverse effect on
human health and/or the environment.
Risk Characterization: The last step in
the risk assessment process; charac-
terizes the potenetial for adverse
health effects and evaluates the degree
of uncertainty involved.
Risk Communication: The exchange of
information about health or environ-
mental risks among risk assessors and
managers, the general public, news
media, interest groups, etc.
Risk Estimate: A description of the
probability that organisms exposed to
a specific dose of a chemical or other
pollutant will develop an adverse re-
sponse, e.g., cancer.
Risk Factor Characteristics (e.g., race,
sex, age, obesity) or variables (e.g.,
smoking, occupational exposure level)
associated with increased probability of
a toxic effect.
Risk Management: The process of
evaluating and selecting alternative
regulatory and non-regulatory respons-
es to risk. The selection process neces-
sarily requires the consideration of
legal, economic, and behavioral factors.
Risk-Specific DOM: The dose associated
with a specified risk level.
River Basin: The land area drained by
a river and its tributaries.
Rodenticide; A chemical or agent used
to destroy rats or other rodent peats, or
to prevent them from damaging food,
crops, etc.
Rotary Kiln Incinerator. An incinerator
with a rotating combustion chamber
that keeps waste moving, thereby
allowing it to vaporize for easier burn-
ing.
Rough Fish: Fish not prized for eating,
such as gar and • suckers. Most are
more tolerant of changing environmen-
tal conditions than game species.
Route of Exposure: The avenue by
which a chemical comes into contact
with an organism, e.g., inhalation,
ingestion, dermal contact, injection.
Rubbish: Solid waste, excluding food
waste and ashes, from homes, institu-
tions, and work-places.
Run-Off. That part of precipitation,
snow melt, or irrigation water that
runs off the land into streams or other
surface-water. It can carry pollutants
from the air and land into receiving
waters.
Running Losses: Evaporation of motor
vehicle fuels from the fuel tank while
the vehicle is in use.
Sacrifical Anode: An easily corroded
material deliberately installed in a
pipe or intake to give it up to corrosion
while the rest of the water supply
facility remains relatively corrosion-
free.
Safe: Condition of exposure under
which there is a practical certrainty
that no harm will result to exposed
indiviuals.
Safener A chemical added to a pesti-
cide to keep it from injuring plants.
Safe Water Water that does not con-
tain harmful bacteria, toxic materials,
or chemicals, and is considered safe for
.drinking even if it may have taste,
odor, color, and certain mineral prob-
lems.
Safe Yield: The annual amount of
water that can be taken from a source
or supply over a period of years with-
out depleting that source beyond its
ability to be replenished naturally in
"wet years."
Salinity: The percentage of salt in
water.
Salt Water Intrusion: The invasion of
fresh surface or ground water by salt
water. If it comes from the ocean it
may be called sea water intrusion.
Salts: Minerals that water picks up as
it passes through the air, over and
under the ground, or from households
and industry.
Salvage: The utilization of waste mate-
rials.
Sanctions: Actions taken by the federal
government for failure to plan or im-
plement a State Improvement Plan
(SIP). Such action may be include
withholding of highway funds and a
ban on construction of new sources of
potential pollution.
Sand Filters: Devices that remove
some suspended solids from sewage.
Air and bacteria decompose additional
wastes filtering through the sand so
that cleaner water drains from the bed.
Sanitary Landfill: (See: landfills.)
Sanitary Sewers: Underground pipes
that carry off only domestic or indus-
trial waste, not storm water.
Sanitary Survey: An on-site review of
the water sources, facilities, equip-
ment, operation and maintenance of a
public water system to evaluate the
adequacy of those elements for produc-
ing and distributing safe drinking
water.
Sanitary Water (Also known as gray
water): Water discharged from sinks,
showers, kitchens, or other nonindus-
trial operations, but not from com-
modes.
Sanitation: Control of physical factors
in the human environment that could
harm development, health, or survival.
Saprophytes: Organisms living on dead
or decaying organic matter that help
natural decomposition of organic mat-
ter in water.
Saturated Zone: The area below the
water table where all open spaces are
filled with water under pressure equal
to or greater than that of the atmo-
sphere.
Saturation: The condition of a liquid
when it has taken into solution the
maximum possible quantity of a given
substance at a given temperature and
pressure.
Scrap: Materials discarded from manu-
facturing operations that may be suit-
able for reprocessing.
Screening: Use of screens to remove
coarse floating and suspended solids
from sewage.
Science Advisory Board (SAB): A
group of external scientists who advise
EPA on science and policy. •
Scrubber An air pollution device that
uses a spray of water or reactant or a
dry process to trap pollutants in emis-
sions.
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36
Secondary Drinking Water Regula-
tions: Non-enforceable regulations
applying to public water systems and
specifying the maximum contamina-
tion levels that, in the judgment of
EPA, are required to protect the public
welfare. These regulations apply to any
contaminants that may adversely af-
fect the odor or appearance of such
water and consequently may cause
people served by the system to discon-
tinue its use.
Secondary Materials: Materials that
have been manufactured and used at
least once and are to be used again.
Secondary Standards: National am-
bient air quality standards designed to
protect welfare, including effects on
soils, water, crops, vegetation, man-
made materials, animals, wildlife,
weather, visibility, and climate; dam-
age to property; transportation haz-
ards; effects on economic values, and
on personal comfort and well-being.
Secondary Treatment: The second step
in most publicly owned waste treat-
ment systems in which bacteria con-
sume the organic parts of the waste. It
is accomplished by bringing together
waste, bacteria, and oxygen in trick-
ling, filters or in the activated sludge
process. This treatment removes float-
ing and settleable solids and about 90
percent of the oxygen-demanding sub-
stances and suspended solids. Disinfec-
tion is the final stage of secondary
treatment. (See: primary, tertiary
treatment.)
Secure Chemical landfill: (See: land-
fills.)
Secure Maximum Contaminant Level:
Maximum permissible level of a con-
taminant in water delivered to the free
flowing outlet of the ultimate user, or
of contamination resulting from corro-
sion of piping and plumbing caused by
water quality.
Sediment Yield The quantity of sedi-
ment arriving at a specific location.
Sedimentation Tanks: Wastewater
tanks in which floating wastes are
skimmed off and settled solids are re-
moved for disposal.
Sedimentation: Letting solids settle out
of wastewater by gravity during treat-
ment. .
Sediments: Soil, sand, and minerals
washed from land into water, usually
after rain. They pile up in reservoirs,
rivers and harbors, destroying fish and
wildlife habitat, and clouding the wa-
ter so that sunlight cannot reach
aquatic plants. Careless farming, min-
ing, and building activities will expose
sediment materials, allowing them to
wash off the land after rainfall.
Seed Protectant: A chemical applied
before planting to protect seeds and
seedlings from disease or insects.
Seepage: Percolation of water through
the soil from unlined canals, ditches,
laterals, watercourses, or water stor-
age facilities.
Selective Pesticide: A chemical de-
signed to affect only certain types of
pests, leaving other plants and animals
unharmed.
Semi-Confined Aquifer An aquifer par-
tially, confined by soil layers of low
permeability through which recharge
and discharge can still occur.
Senescence: The aging process. Some-
times used to describe lakes or other
bodies of water in advanced stages of
eutrophication.
Septic System: An on-site system de-
signed to treat and dispose of domestic
sewage. A typical septic system con-
sists of a tank that receives waste from
a residence or business amd a system
of tile lines or a pit for disposal of the
liquid effluent (sludge) that remains
after decomposition of the solidis by
bacteria in the tank; must be pumped
out periodically.
Septic Tank: An underground storage
tank for wastes from homes not con-
nected to a sewer line. Waste goes di-
rectly from the home to the tank. (See:
septic system.)
Service Connector The pipe that car-
ries tap water from a public water
main to a, building.
Service Line Sample: A one-liter sam-
ple of water collected according to
federal regulations that has been
standing for at least 6 hours in a ser-
vice pipeline.
Service Pipe: The pipeline extending
from the water main to the building
served or to the consumer's system.
Settleable Solids: Material heavy
enough to sink to the bottom of a
wastewater treatment tank.
Settling Chamber A series of screens
placed in the way of flue gases to slow
the stream of air, thus helping gravity
to pull particles into a collection de-
vice.
Settling Tank: A holding area for
wastewater, where heavier particles
sink to the bottom for removal and
disposal.
7Q10: Seven-day, consecutive low flow
with a ten year return frequency; the
lowest stream flow for seven consecu-
tive days that would be expected to
occur once in ten years.
Sewage: The waste and wastewater
produced by residential and commer-
cial sources and discharged into sew-
ers.
Sewage Lagoon: (See: lagoon.)
Sewage Sludge: Sludge produced at a
Publicly Owned Treatment Works, the
disposal of which is regulated under
the Clean Water Act.
Sewer A channel or conduit that car-
ries wastewater and storm-water run-
off from the source to a treatment
plant or receiving stream. "Sanitary"
sewers carry household, industrial,
and commercial waste. "Storm" sewers
carry runoff from rain or snow. "Com-
bined" sewers handle both.
Sewerage: The entire system of sewage
collection, treatment, and disposal.
Sharps: Hypodermic needles, syringes
(with or without the attached needle)
pasteur pipettes, scalpel blades, blood
vials, needles with attached tubing,
and culture dishes used in animal or
human patient care or treatment, or in
medical, research or industrial labo-
ratories. Also included are other types
of broken or unbroken glassware that
were in contact with infectious agents,
such as used slides and cover slips,
and unused hypodermic and suture
needles, syringes, and scalpel blades.
Shock Load: The arrival at a water
treatment plant of raw water contain-
ing unusual amounts of algae, colloidal
matter, color, suspended solids, tur-
bidity, or other pollutants.
Short-Circuiting: When some of the
water in tanks or basins flows faster
than the rest; may result in shorter
contact, reaction, or settling times than
calculated or presumed.
Signal: The volume or product-level
change produced by a leak in a tank.
Signal Words: The words used on a
pesticide label—Danger, Warning, Cau-
tion—to indicate level of toxicity.
Significant Deterioration: Pollution re-
sulting from a new source in previous-
ly "clean" areas. (See: prevention of
significant deterioration.)
Significant Municipal Facilities: Those
publicly owned sewage treatment
plants that discharge a million gallons
per day or more and are therefore
considered by states to have the poten-
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37
tial to substantially effect the quality
of receiving waters.
Significant Non-Compliance: (See: sig-
nificant violations.)
Significant Violations: Violations by
point source dischargers of sufficient
magnitude or duration to be a regula-
tory priority.
Silt: Sedimentary materials composed
of fine or intermediate-sized mineral
particles.
Silviculture: Management of forest
land for timber.
Sink: Place in the environment where
a compound or material collects.
Sinking: Controlling oil spills by using
an agent to trap the oil and sink it to
the bottom of the body of water where
the agent and the oil are biodegraded.
Site: An area or place within the juris-
diction of the EPA and/or a state.
Site Assessment Program: A means of
evaluating hazardous waste sites
through preliminary assessments and
site inspections to develop a Hazard
Ranking System score.
Site Inspection: The collection of infor-
mation from a Superfund site to deter-
mine the extent and severity of haz-
ards posed by the site. It follows and is
more 'extensive than a preliminary
assessment. The purpose is to gather
information necessary to score the site,
using the Hazard Ranking System, and
to determine if it presents an immedi-
ate threat requiring prompt removal.
Site Safety Flan: A cruciaL element in
all removal actions, it includes infor-
mation on equipment being used, pre-
cautions to be taken, and steps to take
in the event of an on-site emergency.
Siting: The process of choosing a loca-
tion for a facility.
Skimming: Using a machine to remove
oil or scum from the surface of the
water.
Slow Sand Filtration: Passage of raw
water through a bed of sand at low
velocity, resulting in substantial re-
moval of chemical and biological con-
taminants.
Sludge: A semi-solid residue from any
of a number of air or water treatment
processes; can be a hazardous waste.
Sludge Digester. Tank in which com-
plex organic substances like sewage
sludges are biologically dredged. Dur-
ing these reactions, energy is released
and much of the sewage is converted to
methane, carbon dioxide, and water.
Slurry: A watery mixture of insoluble
matter resulting from some pollution
control techniques.
Small Quantity Generator (SQG-some-
times referred to as "Squeegee"): Per-
sons or enterprises that produce 220-
2200 pounds per month of hazardous
waste; are required to keep more re-
cords than conditionally exempt gener-
ators. The largest category of hazard-
ous waste generators, SQGs include
automotive shops, dry cleaners, photo-
graphic developers, and a host of other
small businesses. (See: conditionally
exempt generators).
Smelter. A facility that melts or fuses
ore, often with an accompanying chem-
ical change, to separate its metal con-
tent. Emissions cause pollution.
"Smelting" is the process involved. '
Smog: Air pollution associated with
oxidants. (See: photochemical smog.)
Smoke: Particles suspended in air after
incomplete combustion.
Soft Detergents: Cleaning agents that
break down in nature.
Soft Water: Any water that does not
contain a significant amount of dis-
solved minerals such as salts of calci-
um or magnesium.
Soil Adsorption Field: A sub-surface
area containing a trench or bed with
clean stones and a system of piping
through which treated sewage may
seep into the surrounding soil for fur-
ther treatment and disposal.
Soil and Water Conservation Practices:
Control measures consisting of mana-
gerial, vegetative, and structural prac-
tices to reduce the loss of soil and
water.
Soil Conditioner: An organic material
like humus or compost that helps soil
absorb water, build a bacterial commu-
nity, and take up mineral nutrients.
Soil Erodibility: An indicator of a soil's
susceptibility to raindrop impact, run-
off, and other erosive processes.
Soil Gas: Gaseous elements and com-
pounds in the small spaces between
particles of the earth and soil. Such
gases can be moved or driven out un-
der pressure.
Soil Sterilante A chemical that tempo-
rarily or permanently prevents the
growth of all plants and animals.
Solder Metallic compound used to seal
joints between pipes. Until recently,
most solder contained 50 percent lead.
Use of lead solder containing more
than 0.2 percent lead in pipes carrying
drinking water is now prohibited.
Sole-Source Aquifer An aquifer that
supplies 50-percent or more pf the
drinking water of an area.
Solid Waste: Non-liquid, non-soluble
materials ranging from municipal
garbage to industrial wastes that con-
tain complex and sometimes hazardous
substances. Solid wastes also include
sewage sludge, agricultural refuse,
demolition wastes, and mining resi-
dues. Technically, solid waste also
refers to liquids and gases in contain-
ers.
Solid Waste Disposal: The final place-
ment of refuse that is not salvaged or
recycled.
Solid Waste Management: Supervised
handling of waste materials from their
source through recovery processes to
disposal.
Solidification and Stabilization: Remov-
al of wastewater from a waste or
changing it chemically to make it less
permeable and susceptible to transport
by water.
Soot: Carbon dust formed by incom-
plete combustion.
Sorption: The action of soaking up or
attracting substances; process used in
many pollution control systems.
Source Reduction: Reducing the
amount of materials entering the
waste stream by redesigning products
or patterns of production or consump-
tion (e.g., using returnable beverage
containers). Synonymous with waste
reduction.
Source Separation: Segregating various
wastes at the point of generation (e.g.,
separation of paper, metal and glass
from other wastes to make recycling
simpler and more efficient.)
Special Review: Formerly known as
Rebuttable Presumption Against Regis-
tration (RPAR), this is the regulatory
process through which existing pesti-
cides suspected of posing unreasonable
risks to human health, non-target
organisms, or the environment are
referred for review by EPA. Such re-
view requires an intensive risk/benefit
analysis with opportunity for public
comment. If risk is found to outweigh
social and economic benefits, regula-
tory actions ranging from label revi-
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38
. sions and use-restriction to cancella-
tion or suspended registration can be
initiated.
Special Waste: Items such as house-
hold hazardous waste, bulky wastes
(refrigerators, pieces of furniture, etc.)
tires, and used oil.
Species: A reproductively isolated ag-
gregate of interbreeding organisms.
Specific Conductance: Rapid method of
estimating the dissolved solid content
of a water supply by testing its capaci-
ty to carry an electrical current.
Specific Yield The amount of water a
unit volume of saturated permeable
rock will yield when drained by gravi-
ty.
Spill Prevention Control and Counter-
measures Plan (SPCP): Plan covering
the release of hazardous substances as
defined in the Clean Water Act.
Spoil: Dirt or rock removed from its
original location—destroying the compo-
sition of the soil in the process—as in
strip-mining, dredging, or construction.
Sprawl: Unplanned development of
open land.
Spray Tower Scrubber A device that
sprays alkaline water into a chamber
where acid gases are present to aid in
the neutralizing of the gas.
Spring: Ground water seeping out of
the earth where the water table inter-
sects the ground surface.
Spring Mell/Thaw: The process where-
by warm temperatures melt winter
snow and ice. Because various forms of
acid deposition may have been stored
in the frozen water, the melt can result
in abnormally large amounts of acidity
entering streams and rivers, some-
times causing fish kills.
Stable Air. A motionless mass of air
that holds instead of dispersing pollut-
ants.
Stabilization: Conversion of the active
organic matter in sludge into inert,
harmless material.
Stabilization Ponds: (See: lagoon.)
Stack: A chimney, smokestack, or ver-
tical pipe that discharges used air.
Stack Effect: Air, as in a chimney, that
moves upward because it is warmer
than the ambient atmosphere.
Stack Gas: (See: flue gas.)
Stage II Controls: Systems placed on
service station gasoline pumps to con-
trol and capture gasoline vapors dur-
ing refuelling.
Stagnation: Lack of motion in a mass
of air or water that holds pollutants in
place.
Standard Sample: The part of finished
drinking water that is examined for
the presence of coliform bacteria.
Standards: Norms that impose limits
on the amount of pollutants or emis-
sions produced. EPA establishes mini-
mum standards, but states are allowed
to be stricter.
Start of a Response Action: The point
in time when there is a guarantee or
set-aside of funding either by EPA,
other federal agencies, states or Princi-
pal Responsible Parties in order to
begin response actions at a Superfund
site.
State Emergency Response Commis-
sion (SERC): Commission appointed by
each state governor according to the
requirements of SARA Title III. The
SERCs designate emergency planning
districts, appoint local emergency plan-
ning committees, and supervise and
coordinate their activities.
State Implementation Flans (SIP):
EPA-approved state plans for the es-
tablishment, regulation, and enforce-
ment of air pollution standards.
Static Water Depth: The vertical dis-
tance from the center-line .of the pump
discharge down to the surface level of
the free pool while no water is being
drawn from the pool or water table.
Static Water Level: 1. Elevation or
level of the water table in a well when
the pump is not operating. 2. The level
or elevation to which water would rise
in a tube connected to an artesian
aquifer or basin in a conduit under
pressure.
Stationary Source: A fixed-site produc-
er of pollution, mainly power plants
and other facilities using industrial
combustion processes.
Sterilization: The removal or destruc-
tion of all microorganisms, including
pathogenic and other bacteria, vegeta-
tive forms, and spores.
Storage: Temporary holding of waste
pending treatment or disposal, as in
containers, tanks, waste piles, and
surface impoundments.
Storm Sewer A system of pipes (sepa-
rate from sanitary sewers) that carries
only water runoff from buildings and
land surfaces.
Stratification: Separating into layers.
Stratosphere: The portion of the atmo-
sphere 10-to-25 miles above the earth's
surface. •
Strip-Cropping: Growing crops in a
systematic arrangement of strips or
bands that serve as barriers to wind
and water erosion.
Strip-Mining: A process that uses ma-
chines to scrape soil or rock away from
mineral deposits just under the earth's
surface.
Structural Deformation: Distortion in
walls of a tank after liquid has been
added or removed.
Subchronic: Of intermediate duration,
usually used to describe studies or
periods of exposure lasting between 5
and 90 days
Submerged Aquatic Vegetation: Vege-
tation such as sea grasses that cannot
withstand excessive drying and there-
fore live with their leaves at or below
the water surface; an important habi-
tat for young fish and other aquatic
organisms.
Sulfur Dioxide (SOJ: A pungent, color-
less, gaseous pollutant formed primari-
ly by the combustion of fossil fuels.
Sump: A pit or tank that catches liquid
runoff for drainage or disposal.
Superchlorination: Chlorination with
doses that are deliberately selected to
produce water free of combined residu-
als so large as to require dechlorina-
tion.
Supercritical Water A type of thermal
treatment using moderate tempera-
tures and high pressures to enhance
the ability of water to break down
large organic molecules into smaller,
less toxic ones. Oxygen injected during
this process combines with simple
organic compounds to form carbon di-
oxide and water.
Superfund: The program operated
under the legislative authority of
CERCLA and SARA that funds and
carries out EPA solid waste emergency
and long-term removal and remedial
activities. These activities include
establishing the National Priorities
Last, investigating sites for inclusion
on the list, determining their priority,
and conducting and/or supervising the
cleanup and other remedial actions.
Superfund Innovative Technology
Evaluation: EPA program to promote
development and use of innovative
treatment technologies in Superfund
site cleanups.
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39
Supplier of Water Any person who
owns or operates a public water sup-
ply.
Surface Impoundment: Treatment,
storage, or disposal of liquid hazardous
wastes in ponds.
Surface Runoff: Precipitation, snow-
melt, or irrigation water in excess of
what can infiltrate the soil surface and
be stored in small surface depressions;
a major transporter of non-point source
pollutants.
Surface Uranium Mines: Strip mining
operations for removal of uranium-
bearing ore.
Surface Water All water naturally
open to the atmosphere (rivers, lakes,
reservoirs, ponds, streams, impound-
ments, seas, estuaries, etc.) and all
springs, wells, or other collectors di-
rectly influenced by surface water.
Surfacing ACM: Asbestos-containing
material that is sprayed or troweled on
or otherwise applied to surfaces, such
as acoustical plaster on ceilings and
fireproofing materials on structural
members.
Surfacing Material: Material sprayed
or troweled onto structural members
(beams, columns, or decking) for fire
protection; or on ceilings or walls for
fireproofing, acoustical or decorative
purposes. Includes textured plaster,
and other textured wall and ceiling
surfaces.
Surfactant: A detergent compound that
promotes lathering.
Surveillance System: A series of moni-
toring devices designed to check on
environmental conditiona.
Suspect Material: Building material
suspected of containing asbestos, e.g.,
surfacing material, floor tile, ceiling
tile, thermal system insulation, and
miscellaneous other materials.
Suspended Loads: Sediment particles
maintained in the water column by
turbulence and carried with the flow of
water.
Suspended Solids: Small particles of
solid pollutants that float on the sur-
face of, or are suspended in) sewage or
other liquids. They resist removal by
conventional means.
Suspension: Suspending the use of a
pesticide when EPA deems it necessary
to prevent an imminent hazard result-
ing from its continued use. An emer-
gency suspension takes effect imme-
diately; under an ordinary suspension
a registrant can request a hearing
before the suspension goes into effect.
Such a hearing process might take six
months.
Suspension Culture: Cells growing in a
liquid nutrient medium.
Swamp: A type of wetland dominated
by woody vegetation but without ap-
preciable peat deposits. Swamps may
be fresh or salt water and tidal- or
non-tidal. (See: wetlands.)
Synergism: An interaction of two or
more chemicals that results in an ef-
fect greater than the sum of their
separate effects.
Synthetic Organic Chemicals (SOCs):
Man-made organic chemicals. Some
SOCs are volatile, others tend to stay
dissolved in water instead of evaporat-
ing.
System With a Single Service Connec-
tion: A system that supplies drinking
water to consumers via a single service
line.
Systemic Pesticide: A chemical ab-
sorbed by an organism that makes the
organism toxic to pests.
Tailings: Residue of raw material or
waste separated out during the pro-
cessing of crops or mineral ores.
Tailpipe Standards: Emissions limita-
tions applicable to mobile source en-
gine exhausts.
Tail Water. The runoff of irrigation
water from the lower end of an irrigat-
ed field.
Tampering: Adjusting, negating, or
removing pollution control equipment
on a motor vehicle.
Technical Assistance Grant (TAG): As
part of the Superfund program, Tech-
nical Assistance Grants of up to
$60,000 are provided to citizens'
groups to obtain assistance in inter-
preting information related to cleanups
at Superfund sites or those proposed
for the National Priorities Last. Grants
are used by such groups to hire techni-
cal advisors to help them understand
the site-related technical information
for the duration of response activities.
Technology-Based Limitations: Indus-
try-specific effluent limitations applied
to a discharge when it will not cause a
violation of water quality standards at
low stream flows. Usually applied to
discharges into large rivers.
Technology-Based Standards: Effluent
limitations applicable to direct and
indirect sources which are 'developed
on a category-by-category basis using
statutory factors, not including water-
quality effects.
Teratogenesis: The introduction of non-
hereditary birth defects in a developing
fetus by exogenous factors such as
physical or chemical agents acting in
the womb to interfere with normal
embryonic development.
Terracing: Dikes built along the con-
tour of sloping farm land that hold
runoff and sediment to reduce erosion.
Tertiary Treatment: Advanced cleaning
of wastewater that goes beyond the
secondary or biological stage, removing
nutrients such as phosphorus, nitro-
gen, and most BOD and suspended
solids.
Therapeutic Index: The ratio of the
dose required to produce toxic or lethal
effects to dose required to produce
nonadverse or therapeutic response.
Thermal Pollution: Discharge of heated
water from industrial processes; can
kill or injure aquatic organisms.
Thermal Stratification: The formation
of layers of different temperatures in a
lake or reservoir.
Thermal System Insulation (TSI>
Asbestos-containing material applied to
pipes, fittings, boilers, breeching,
tanks, ducts, or other interior struc-
tural components to prevent heat loss
or gain or water condensation.
Thermal Treatment: Use of elevated
temperatures to treat hazardous
wastes. (See: incineration; pyrolysis.)
Thermodine: The middle layer of a
thermally stratified lake or reservoir.
In this layer there is a rapid decrease
in temperatures in a lake or reservoir.
Threshold: The lowest dose of a chemi-
cal at which a specified measurable
effect is observed and below which it is
not observed.
Threshold Level: Time-weighted aver-
age pollutant concentration values,
exposure beyond which is likely to
adversely affect human health. (See:
environmental exposure)
Threshold Limit Value (TLV): The
concentration of an airborne substance
that an average person can be repeat-
edly exposed to without adverse effects.
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40
TLVs may be expressed in three ways:
TLV-TWA-Time weighted average,
based on an allowable exposure aver-
aged over a normal 8-hour workday or
40-hour workweek; TLV-STEL-Short-
term exposure limit or maximum con-
centration for a brief specified period of
time, depending on a specific chemical
(TWA must still be met); and TLV-C-
Ceiling Exposure Limit or maximum
exposure concentration not to be ex-
ceeded under any circumstances. (TWA
must still be met.)
Threshold Odor (See: Odor threshold)
Threshold Planning Quantity: A quan-
tity designated for each chemical on
the list of extremely hazardous sub-
stances that triggers notification by
facilities to the State Emergency Re-
sponse Commission that such facilities
are subject to emergency planning re-
quirements under SARA Title III.
Tidal Marsh: Low, flat marshlands tra-
versed by channels and tidal hollows,
subject to tidal inundation; normally,
the only vegetation present is salt-
tolerant bushes and grasses. (See:
wetlands.)
Tillage: Plowing, seedbed preparation,
and cultivation practices.
Total Suspended Particles: A method of
monitoring particulate matter by total
weight.
Time-weighted Average (TWA): In air
sampling, the average air concentra-
tion of contaminants during a given
period.
Tolerances: Permissible residue levels
'for pesticides in raw agricultural pro-
duce and processed foods. Whenever a
pesticide is registered for use on a food
or a feed crop, a tolerance (or exemp-
tion from the tolerance requirement)
must be established. EPA establishes
the tolerance levels, which are enforced
by the Food and Drug Administration
and the Department of Agriculture.
Tonnage: The amount of waste that a
landfill accepts, usually expressed in
tons per month. The rate at which a
landfill accepts waste is limited by the
landfill's permit.
Topography: The physical features of a
surface area including relative eleva-
tions and the position of natural and
man-made features.
Total Dissolved Phosphorous: The total
phosphorous content o. all material
that will pass through a filter, which is
determined as orthophosphate without
prior digestion or hydrolysis. Also
called soluble P. or ortho P.
Total Dissolved Solids (TDS): All mate-
rial that passes the standard glass
river filter; now called total filterable
residue. Term is used to reflect salini-
ty.
Total Suspended Solids (TSS): A mea-
sure of the suspended solids in
wastewater, effluent, or water bodies,
determined by tests for "total suspend-
ed non-filterable solids." (See: suspend-
ed solids.)
Toxaphene: Chemical that causes ad-
verse health effects in domesic water
supplies and is toxic to fresh water and
marine aquatic life.
Toxic Chemical Release Form: Infor-
mation form required of facilities that
manufacture, process, or use (in quan-
tities above a specific amount) chemi-
cals listed under SARA Title III.
Toxic Chemical: Any chemical listed in
EPA rules as "Toxic Chemicals Subject
to Section 313 of the Emergency Plan-
ning and Community Right-to-Know
Act of 1986."
Toxic Chemical Use Substitution: Re-
placing toxic chemicals with less harm-
ful chemicals in industrial processes.
Toxic Cloud: Airborne plume of gases,
vapors, fumes, or aerosols containing
toxic materials.
Toxic Pollutants: Materials that cause
death, disease, or birth defects in or-
ganisms that ingest or absorb them.
The quantities and exposures neces-
sary to cause these effects can vary
widely.
Toxic Release Inventory: Database of
toxic releases in the United States
compiled from SARA Title III section
313 reports.
Toxic Substance: A chemical or mix-
ture that may present an unreasonable
risk of injury to health or the environ-
ment.
Toxic Waste: A waste that can produce
injury if inhaled, swallowed, or ab-
sorbed through the skin.
Toxicant: A harmful substance or
agent that may injure an exposed
organism.
Toxitity Assessment: Characterization
of the toxicological properties and ef-
fects of a chemical, with special em-
phasis on establishment of dose-re-
sponse characteristics.
Tooricity Testing: Biological testing
(usually with an invertebrate, fish, or
small mammal) to determine the ad-
verse effects of a compound or efflu-
ent.
Toxicological Profile: An examination,
summary, and interpretation of a haz-
ardous substance to determine levels of
exposure and associated health effects.
Transboundary Pollutants: Air pollu-
tion that travels from one jurisdiction
to another, often crossing state or
international boundaries. Also applies
to water pollution.
Transient Water System: A non-com-
munity water system that does not
serve 25 of the same nonresidents per
day for more than six months per year.
Transmission Lines: Pipelines that
transport raw water from its source to
a water treatment plant, then to the
distribution grid system.
Transmissivity: The ability of an aqui-
fer to transmit water,
Transpiration: The process by which
water vapor is lost to the atmosphere
from living plants. The term can also
be applied to the quantity of "water
thus dissipated.
Transportation Control Measures
(TCMs): Steps taken by a locality to
adjust traffic patterns (e.g., bus lanes,
turnout, right turn on red) or reduce
vehicle use (ride sharing, high-occu-
pancy vehicle lanes) to cut vehicular
emissions.
Trash: Material considered worthless
or offensive that is thrown away. Gen-
erally defined as dry waste material,
but in common usage it is a synonym
for garbage, rubbish, or refuse.
Trash-to-Energy Han: Burning trash
to produce energy.
Treatability Studies: Tests of potential
cleanup technologies conducted in a
laboratory (See: bench-scale tests.)
Treated Regulated Medical Waste:
Medical waste treated to substantially
reduce or eliminate its pathogenicity,
but that has not yet been destroyed.
Treated Wastewater: Waste-water that
has been subjected to one or more
physical, chemical, and biological pro-
cesses to reduce its pollution or health
hazards.
Treatment: (1) Any method, technique,
or process designed to remove solids
and/or pollutants from solid waste,
wastestreams, effluents, and air emis-
sions. (2) methods used to change the
biological character or composition of
any regulated medical waste so as to
substantially reduce or eliminate its
potential for causing disease.
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41
Treatment Plant: A structure built to
treat wastewater before discharging it
into the environment
Treatment, Storage, and Disposal
Facility: Site where a hazardous sub-
stance is treated, stored, or disposed
of. TSD facilities are regulated by EPA
and states under RCRA.
Tremie: Device used to place concrete
or grout under water.
Trial Burn: An incinerator test in
which emissions are monitored for the
presence of specific organic compounds,
particulates, and hydrogen chloride.
Trichloroethyiene (TCE): A stable, low
boiling-point colorless liquid, toxic if in-
haled. Used as a solvent or metal de-
greasing agent, and in other industrial
applications.
Trickling Filter A coarse treatment
system in which wastewater is trickled
over a bed of stones or other material
covered with bacteria that break down
the organic waste and produce clean
water.
Trickle Irrigation: Method in which
water drips to the soil from perforated
tubes or emitters.
TVihiil««M«»t>nin«» ^TOM): One of a fami-
ly of organic compounds named as
derivative of methane. THMs are gen-
erally by-products of chlorination of
drinking water that contains organic
material.
Troposhpere: The layer of the atmo-
sphere closest to the earth's surface.
Trust Fond (CERCLA): A fund set up
iinA»r the Comprehensive Environmen-
tal Response, Compensation and Lia-
bility Act (CERCLA) to help pay for
cleanup of hazardous waste sites and
for legal action to force those responsi-
ble for the sites to clean them up.
Tube Settler Device using bundles of
tubes to let solids in water settle to the
bottom for removal by conventional
sludge collection means; sometimes
used in sedimentation basing and clari-
fiers to improve particle removal.
Tuberculation: Development or forma-
tion of small mounds of corrosion pro-
ducts on the inside of iron pipe. These
tubercules roughen the imiide of the
pipe, increasing its resistance to water
flow.
Tundra: A type of ecosystem dominat-
ed by lichens, mosses, grasses, and
woody plants. Tundra is found at high
latitudes (arctic tundra) and high alti-
tudes (alpine tundra). Arctic tundra is
underlain by permafrost and is usually
saturated. (See: wetlands.)
Turbidimeter A device that measures
the density of suspended solids in a
liquid.
Turbidity: 1. Haziness in air caused by
the presence of particles and pollut-
ants. 2. A cloudy condition in water
due to suspended silt or organic mat-
ter.
u
Ultra Clean Coal (UCC): Coal that is
washed, ground into fine particles,
then chemically treated to remove
sulfur, ash, silicone, and other sub-
stances; usually briquetted and coated
with a sealant made from coal.
Ultraviolet Rays: Radiation from the
sun that can be useful or potentially
harmful. UV rays from one part of the
spectrum (UV-A) enhance plant life
and are useful in some medical and
dental procedures; UV rays from other
parts of the spectrum (UV-B) can
cause skin cancer or other tissue dam-
age. The ozone layer in the atmosphere
partly shields us from ultraviolet rays
reaching the earth's surface.
Unconfined Aquifer An aquifer con-
taining water that is not under pres-
sure; the water level in a well is the
same as the water table outside the
well.
Underground Injection Control (UIC>
The program under the Safe Drinking
Water Act that regulates the use of
wells to pump fluids into the ground.
Underground Sources of Drinking
Water Aquifers currently being used
as a source of drinking water or those
capable of supplying a public water
system. They have a total dissolved
solids content of 10,000 milligrams per
liter or less, and are not "exempted
aquifers." (See: exempted aquifer.)
Underground Storage Tank: A tank
located at least partially underground
and designed to hold gasoline or other
petroleum products or chemicals.
Unreasonable Risk: Under the Federal
Insecticide, Fungicide, and Rodenticide
Act (FIFRA), "unreasonable adverse ef-
fects" means any unreasonable risk to
man or the environment, taking into
account the medical, economic, social,
and environmental costs and benefits
of any pesticide.
Unsaturatod Zone: The area above the
water table where soil pores are not
fully saturated, although some water
may be present
Uranium Mill Tailing! Piles: Former
uranium ore processing sites that con-
tain leftover radioactive materials
(wastes), including radium and unre-
coverad uranium.
Uranium Mill-Tailings Waste Piles: Li-
censed active mills with tailings piles
and evaporation ponds created by acid
or alkaline leaching processes.
Urban Runoff: Storm water from city
streets and adjacent domestic or com-
mercial properties that carries pollut-
ants of various kinds into the sewer
systems and receiving waters.
Urea-Formaldehyde Foam Insulation:
A material once used to conserve ener-
gy by sealing crawl spaces, attics, etc.;
no longer used because emissions were
found to be a health hazard.
User Fee: Fee collected from only those
persons who use a particular service,
as compared to one collected from the
public in general.
Utility Load: The total electricity de-
mand for a utility district
Vapor Capture System: Any combina-
tion of hoods and ventilation system
that, captures or contains organic va-
pors so they may be directed to an
abatement or recovery device.
Vapor Dispersion: The movement of
vapor clouds in air due to wind, ther-
mal action, gravity spreading, and
mi-ring
Vapor Plumes: Flue gases visible be-
cause they contain water droplets.
Variance: Government permission for
a delay or exception in the application
of a given law, ordinance, or regula-
tion.
Vector 1. An organism, often an insect
or rodent, that carries disease. 2. Pla-
amids, viruses, or bacteria used to
transport genes into a host cell. A gene
is placed in the vector; the vector then
"infects" the bacterium.
Vegetative Controls: Non-point source
pollution control practices that involve
vegetative cover to reduce erosion and
minimi™ loss of pollutants.
Vehicle Miles Travelled (VMT> A mea-
sure of the extent of motor vehicle
operation; the total number of vehicle
miles travelled within a specific geo-
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42
graphic area over a given period of
time.
Ventilation/Suction: The act of admit-
ting fresh air into a space in order to
replace stale or contaminated air;
achieved by blowing air into the space.
Similarly, suction represents the ad-
mission of fresh air into an interior
space by lowering the pressure outside
of the space, thereby drawing the con-
taminated air outward.
Venturi Scrubbers: Air pollution con-
trol devices that use water to remove
particulate matter from emissions.
Vinyl Chloride: A chemical compound,
used in producing some plastics, that
is believed to be oncogenic.
Virgin Materials: Resources extracted
from nature in their raw form, such as
timber or metal ore.
Volatile: Any substance that evapo-
rates readily.
Volatile Liquids: Liquids which easily
vaporize or evaporate at room tempera-
ture.
Volatile Organic Compound (VOC>.
Any organic compound that partici-
pates in atmospheric photochemical
reactions except those designated by
EPA as having negligible photochemi-
cal reactivity.
Volatile Solids Those solids in water or
othr liquids that are lost on ignition of
the dry solids at 550* Centigrade.
Volatile Synthetic Organic Chemicals:
Chemicals that tend to volatilize or
evaporate.
Volume Reduction: Processing waste
materials to decrease the amount of
space they occupy, usually by compact-
ing or shredding, incineration, or
composting.
Volumetric Tank Test: One of several
tests to determine the physical integri-
ty of a storage tank; the volume of
fluid in the tank is measured directly
or calculated from product-level chang-
es. A marked drop in volume indicates
a leak.
Vulnerable Zone: An area over which
the airborne concentration of a chemi-
cal accidentally released could reach
the level of concern.
Vulnerability Analysis: Assessment of
elements in the community that are
susceptible to damage should a release
of hazardous materials occur.
w
Waste: 1. Unwanted materials left over
from a manufacturing process. 2. Re-
fuse from places of human or animal
habitation.
Waste Characterization: Identification
of chemical and microbiological constit-
uents of a waste material.
Waste Exchange: Arrangement' in
which companies exchange their
wastes for the benefit of both parties.
Waste Feed: The continuous or inter-
mittent flow of wastes into an incin-
erator.
Waste Load Allocation: 1. The maxi-
mum load of pollutants each discharg-
er of waste is allowed to release into a
particular waterway. Discharge limits
are usually required for each specific
water quality criterion being, or ex-
pected to be, violated. 2. The portion of
a stream's total assimilative capacity
assigned to an individual discharge.
Waste Minimization: Measures or tech-
niques that reduce the amount of
wastes generated during industrial
production processes; term is also ap-
plied to recycling and other efforts to
reduce the amount of waste going into
the waste, stream.
Waste Reduction: Using source reduc-
tion, recycling, or composting to pre-
vent or reduce waste generation.
Waste Stream: The total flow of solid
waste from homes, businesses, institu-
tions, and manufacturing plants that
are. recycled, burned, or disposed of in
landfills, or segments thereof such as
the "residential waste stream" or the
"recyclable waste stream."
Waste Treatment Lagoon: Impound-
ment made by excavation or earth fill
for biological treatment of wastewater.
Waste Treatment Plant* A facility con-
taining a series of tanks, screens, fil-
ters and other processes by which
pollutants are removed from water.
"Waste Treatment Stream: The continu-
ous movement of waste from generator
to treater and disposer.
Wastewater The spent or used water
from a home, community, farm, or
industry that contains dissolved or
suspended matter.
Wastewater Infrastructure: The plan
or network for the collection, treat-
ment, and disposal of sewage in a
community. The level of treatment
will depend on the size of the commu-
nity, the type of discharge, and/or the
designated use of the receiving water.
Wastewater Operations and Mainte-
nance: Actions taken after construction
to assure that facilities constructed to
treat wastewater will be operated,
maintained, and managed to reach pre-
scribed effluent levels in an optimum
manner.
Water Pollution: The presence in water
of enough harmful or objectionable
material to damage the water's quality.
Water Purveyor A public utility, mu-
tual water company, county water
district, or municipality that delivers
drinking water to customers.
Water Quality Criteria: Levels of water
quality expected to render a body of
water suitable for its designated use.
Criteria are. based on specific levels of
pollutants that would make the water
harmful if used for drinking, swim-
ming, farming, fish production, or
industrial processes.
Water Quality Standards: State-adopt-
ed and EPA-approved ambient stan-
dards for water bodies. The standards
prescribe the use of the water body
and establish the water quality criteria
that must be met to protect designated
uses.
Water Quality-Based Limitations:
Effluent limitations applied to dis-
chargers when mere technology-based
limitations would cause violations of
water quality standards. Usually ap-
plied to discharges into small streams.
Water Quality-Baaed Permit A permit
with an effluent limit more stringent
than one based on technology perfor-
mance. Such limits may be necessary
to protect the designated use of receiv-
ing waters (i.e., recreation, irrigation,
industry or water supply).
Water Solubility: The mummim possi-
ble concentration of a chemical com-
pound dissolved in water. If a sub-
stance is water soluble it can very
readily disperse through the environ-
ment
Water Storage Pond: An impound for
liquid wastes designed to accomplish
some degree of biochemical treatment
Water Supplier: One who owns or
operates a public water system.
Water Supply System: The collection,
treatment, storage, and distribution of
potable water from source to consumer.
Water Table: The level of grbundwater.
Water Treatment Lagoon: An impound
for liquid wastes designed to accom-
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43
pilch some degree of biochemical treat-
ment.
Water Well: An excavation where the
intended use is for location, acquisi-
tion, development, or artificial. re-
charge of ground water.
Watorbome Disease Outbreak; The
significant occurence of acute infection
illness associated with drinking water
from a public water system that is
deficient in treatment, as determined
by appropriate local or state agencies,
or from untreated water sources.
Watershed: The land area that drains
into a stream; the watershed for a
major river may encompass a number
of smaller watersheds that ultimately
combine at a common point
Weir 1. A wall or plate placed in an
open channel to measure the flow
ofwater. 2. A wall or obstruction used
to control flow from settling tanks and
clarifiers to assure a uniform flow rate
and avoid short-circuiting. (See: short-
circuiting.)
Well: A bored, drilled, or driven shaft,
or a dug hole whose depth is greater
than the largest surface dimension and
whose purpose is to reach underground
water supplies or oil, or to store or
bury fluids below ground.
Well Field Area containing one or
more wells that produce usable
amounts of water or oil.
Well Injection: The subsurface em-
placement of fluids into a well.
Well Monitoring: Measurement by on-
sito instruments or laboratory methods
of well water quality.
Well Hug: A watertight, gantight seal
installed in a bore hole or well to pre-
vent movement of fluids.
Wellhead Protection Area: A protected
surface and subsurface sane surround-
ing a well or wellfield supplying a
public water system to keep contami-
nants from reaching the well water.
Wetlands: An area that is saturated by
surface or ground water with vegeta-
tion adapted for life under those soil
conditions, as in swamps, bogs, fens,
marshes, and estuaries.
Wildlife Refuge: An area designated for
the protection of wild animala, within
which hunting and fiohing are either
prohibited or strictly controlled.
Wire-to-Wire Efficiency: The efficiency
of a pump and motor together.
Wood-Burning-Stove Pollution: Air
pollution caused by emissions of partic-
ulate matter, carbon monoxide, total
suspended particulates, and polycyclic
organic matter from wood-burning
stoves.
Wood Treatment Facility: An industri-
al facility that treats lumber and other
wood products for outdoor use. The
process employs chromated copper
arsenate, which is regulated as a haz-
ardous material.
Working Level Month (WLM): A unit
of measure used to determine cumula-
tive exposure to radon.
Working Level (WL): A unit of measure
for documenting exposure to radon
decay products, the so-called "daugh-
ters". One working level is equal to
approximately 200 picocuries per liter.
XYZ
Xanobioto: Any biotum displaced from
its normal habitat; a chemical foreign
to a biological system.
Yard Waste: The part of solid waste
composed of grass clippings, leaves,
twigs, branches, and garden refuse.
Yellow-Boy: Iron oxide flocculent
(clumps of solids in waste or water);
usually observed as orange-yellow
deposits in surface streams with excess
iron content. (See: floe, flocculation.)
Yield: The quantity ofwater (expressed
as a rate of flow or total quantity per
year) that can be collected for a given
use from surface or groundwater sourc-
es.
Z-lisfc OSHA's tables of toxic and haz-
ardous air contaminants.
Zone of Aeration: The comparatively
dry soil or rock located between the
ground surface and the top of the wa-
ter table.
Zone of Saturation: (See: saturated
zone.)
Zooplankton: Tiny aquatic
eaten by fish.
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Abbreviations And Acronyms
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43
A&I: Alternative and Innovative
(Wastewater Treatment
System)
AA: Accountable Area; Adverse
Action; Advices of Allowance
Assistant Administrator; As-
sociate Administrator; Atomic
Absorption
AAEE: American Academy of
Environmental Engineers
AANWR Alaskan Arctic Na-
tional Wildlife Refuge
AAP: Asbestos Action Program
AAPCO: American Association
of Pesticide Control Officials
AARC: Alliance for Acid Rain
Control
ABEL: EPA's computer model
for analyzing a violator's abil-
ity to pay a civil penalty.
ABES: Alliance for Balanced
Environmental Solutions
AC: Actual Commitment. Advi-
sory Circular
A&C: Abatement and Control
ACA: American Conservation
Association
ACBM: Asbestos-Containing
Building Material
ACE: Alliance for Clean Energy
ACEEE: American Council for
an Energy Efficient Economy
ACFM: Actual Cubic Feet Per
Minute
ACL: Alternate Concentration
Limit. Analytical Chemistry
Laboratory
ACM: Asbestos-Containing Ma-
terial
ACP: Agriculture Control Pro-
gram (Water Quality Manage-
ment)
ACP: Air Carcinogen Policy
ACQUIRE: Aquatic Information
Retrieval
ACQR Air Quality Control Re-
gion
ACS: American Chemical Soci-
ety
ACT: Action
ACTS: Asbestos Contractor
Tracking System
ACWA: American Clean Water
Association
ACWM: Asbestos-Containing
Waste Material
ADABA: Acceptable Data Base
ADB: Applications Data BaM
ADI: Acceptable Daily Intake
ADP: Automated Data Process-
ing
ADP: AHERA Designated Per-
son
ADQ: Audits of Data Quality
ADR: Alternate Dispute Resolu-
tion
ADSS: Air Data Screening Sys-
tem
ADT: Average Daily Traffic
AEA: Atomic Energy Act
AEC: Associate Enforcement
Counsels
ABE: Alliance for Environmen-
tal Education.
AEERL: Air and Energy Engi-
neering Research Laboratory
AEM: Acoustic Emission Moni-
toring
AERE: Association of Environ-
mental and Resource Econo-
mists
AES: Auger Electron Spectrome-
try
AFA: American Forestry Associ-
ation
AFCA: Area Fuel Consumption
Allocation
AFCEE: Air Force Center for
Environmental Excellence
AFS: AIRS Facility Subsystem
AFUG: AIRS Facility Users
Group
AH: Allowance Holders
AHERA: Asbestos Hazard
Emergency Response Act
AIC: Active to Inert Conversion
AICUZ: Air Installation Com-
patible Use Zones
AID: Agency for International
Development
AJHC: American Industrial
Health Council
AIR Auto Ignition Point
AIRS: Aerometric Information
Retrieval System
AL: Acceptable Level
ALA: Delta- Aminolevulinic Acid
ALA-O: Delta-Aminolevulinic
Acid Dehydrates
ALAPO: Association of Local Air
Pollution Control Officers
ALARA: As Low As Reasonably
Achievable
ALC: Application Limiting Con-
stituent
ALJ: Administrative Law Judge
ALMS: Atomic Line Molecular
Spectroscopy
ALR Action Leakage Rate
AMBIENS: Atmospheric Mass
Balance of Industrially Emit-
ted and Natural Sulfur
AMOS: Air Management Over-
sight System
AMPS: Automatic Mapping and
Planning System
AMSA: Association of Metropoli-
tan Sewer Agencies
ANC: Acid Neutralizing Capaci-
ty
ANPR: Advance Notice of Pro-
posed Rulemaking
ANRHRD: Air, Noise. & Radia-
tion Health Research Divi-
sion/ORD
ANSS: American Nature Study
Society
AOC: Abnormal Operating Con-
ditions
AOD: Argon-Oxygen Decarbon-
ization
AOML: Atlantic Oceanographic
and Meteorological Laborato-
ry
AP: Accounting Point
APA: Administrative Procedures
Act
APCA: Air Pollution Control
Association
APCD: Air Pollution Control
District
APDS: Automated Procurement
Documentation System
APHA: American Public Health
Association
APRAC: Urban Diffusion Model
for Carbon Monoxide from
Motor Vehicle Traffic
APTI: Air Pollution Training
Institute
APWA: American Public Works
Association
AQ-7: Non-reactive Pollutant
Modelling
AQCCT: Air-Quality Criteria
and Control Techniques
AQCP: Air Quality Control Pro-
gram
AQCR Air-Quality Control Re-
gion
AQD: Air-Quality Digest
AQDHS: Air-Quality Date Han-
dling System
AQDM: Air-Quality Display
Model
AQMA: Air-Quality Mainte-
nance Area
AQMP: Air-Quality Mainte-
nance Plan
AQMP: Air-Quality Manage-
ment Plan
AQSM: Air-Quality Simulation
Model
AQTAD: Air-Quality Technical
Assistance Demonstration
Aft Administrative Record •
A&R: Air and Radiation
ARA: Assistant Regional Ad-
ministrator
ARA: Associate Regional Admin-
istrator
ARAR Applicable or Relevant
and Appropriate Standards,
Limitations, Criteria, and
Requirements ••
ARB: Air Resources Board
ARC: Agency Ranking Commit-
tee
ARCC: American Rivers Conser-
vation Council
ARCS: Alternative Remedial
Contract Strategy
ARG: American Resources
Group
ARIP: Accidental Release Infor-
mation Program
ARL: Air Resources Laboratory
ARM: Air Resources Manage-
ment
ARC: Alternate Regulatory Op-
tion
ARRP: Acid Rain Research Pro-
gram
ARRPA: Air Resources Regional
Pollution Assessment Model
ARS: Agricultural Research
Service
ARZ: Auto Restricted Zone
AS: Area Source
ASC: Area Source Category
ASDWA: Association of State
Drinking Water Administra-
tors
ASHAA: Asbestos in Schools
Hazard Abatement Act
ASIWCPA: Association of State
and Interstate Water Pollu-
tion Control Administrators
ASMDHS: Airshed Model Date
Handling System
ASRL: Atmospheric Sciences
Research Laboratory
AST: Advanced Secondary
(Wastewater) Treatment
ASTHO: Association of State
and Territorial Health Offi-
cers
ASTM: American Society for
Testing and Materials
ASTSWMO: Association of State
and Territorial Solid Waste
Management Officials
AT: Advanced Treatment. Alpha
Track Detection
ATERIS: Air Toxics Exposure
and Risk Information System
ATS: Action Tracking System
ATSDR: Agency for Toxic Sub-
stances and Disease Registry
ATTF: Air Toxics Task Force
AUSM: Advanced Utility Simu-
lation Model
A/WPR Au/Water Pollution Re-
port
AWRA: American Water Re-
sources Association
AWT: Advanced Wastewater
Treatment
AWWA: American Water Works
Association
AWWARF: American Water
Works Association Research
Foundation.
B
BAA: Board of Assistance
Appeals
BAC: Biotechnology Advisory
Committee
BACM: Best Available Control
Measures
BACT: Best Available Control
Technology
BADT: Best Available Demon-
strated Technology
BaP: Benzo(a)Pyrene
BAP: Benefits Analysis Program
BART: Best Available Retrofit
Technology
BASIS: Battelle's Automated
Search Information System
BAT: Best Available Technology
BATEA: Best Available Treat-
ment Economically Achiev-
able
BCT: Best Control Technology
BCPCT: Best Conventional Pol-
lutant Control Technology
BDAT: Best Demonstrated
Achievable Technology
BDCT: Best Demonstrated Con-
trol Technology
BDT: Best Demonstrated Tech-
nology
BEJ: Best Engineering Judge-
ment. Best Expert Judgment
BF: Bonafide Notice of Intent to
Manufacture or Import
(IMD/OTS)
BID: Background Information
Document. Buoyancy Induced
Dispersion
-------
44
BIOPLUME: Model to Predict
the Maximum Extent of Ex-
isting Humes
BMP: Best Management Prac-
tice^)
BMR: Baseline Monitoring Re-
port
BO: Budget Obligations
BOA: Basic Ordering Agreement
(Contracts)
BOD: Biochemical Oxygen De-
mand. Biological Oxygen De-
mand
BOF: Basic Oxygen Furnace
BOP: Basic Oxygen Process
BOPF: Basic Oxygen Process
Furnace
BOYSNC: Running of Year
Significant Non-Compliers
BP: Boiling Point
BPJ: Best Professional Judg-
ment
BPT: Best Practicable Technol-
ogy. Pest Practicable Treat-
ment
BPWTT: Best Practical Waste-
water Treatment Technology
BRS: Bibliographic Retrieval
Service
BSI: British Standards Institute
BSO: Benzene Soluble Organics
BTZ: Below the Treatment Zone
BUN: Blood Urea Nitrogen
CA: Citizen Act. Competition
Advocate. Cooperative Agree-
ments. Corrective Action
CAA: Clean Air Act
CAA: Compliance Assurance
Agreement
CAAA: Clean Mr Act Amend-
ments
CAER: Community Awareness
and Emergency Response
CAFE: Corporate Average Fuel
Economy
CAFO: Consent Agree-
1 menl/Final Order
CAG: Carcinogenic Assessment
Group
CAIR Comprehensive Assess-
ment of Information Rule
CALJNE: California Line Source
Model
CAMP: Continuous Air Monitor-
ing Program
CAN: Common Account Number
CAO: Corrective Action Order
CAP: Corrective Action Plan.
Cost Allocation Procedure.
Criteria Air Pollutant
CAR Corrective Action Report
CAS: Center .for Automotive
Safety
CAS: Chemical Abstract Service
CASAC: Clean Air Scientific
Advisory Committee
CASLP: Conference on Alter-
native State and Local Prac-
tices
CATS: Corrective Action
Tracking System
CAU: Carbon Adsorption Unit
CAU: Command Arithmetic
Unit
CB: Continuous Bubbler
CBA: Chesapeake Bay . Agree-
ment. Cost Benefit Analysis
CBD: Central Business District
CBI: Compliance Biomonitoring
Inspection
CBI: Confidential Business In-
formation
CBOD: Carbonaceous Bio-
chemical Oxygen Demand
CBP: Chesapeake Bay Program
CBP: County Business Patterns
CCA: Competition in Contract-
ing Act
CCAA: Canadian Clean Air Act
CCAP: Center for Clean Air
Policy
CCEA: Conventional Combus-
tion Environmental Assess-
ment
CCHW: Citizens Clearinghouse
for Hazardous Wastes
CCID: Confidential Chemicals
Identification System
CCMS/NATO: Committee on
Challenges of a Modern Soci-
ety/North Atlantic Treaty
Organization
CCP: Composite Correction Plan
CC/RTS:Chemical Collection/
Request Tracking System
CCTP: Clean Coal Technology
Program
CD: Climatological Data
CDB: Consolidated Data Base
CDBA: Central Data Base Ad-
ministrator
CDBG: Community Develop-
ment Block Grant
CDD: Chlorinated
dibenzo-p-dicorin
CDF: Chlorinated dibenzofuran
CDHS: Comprehensive Data
Handling System
GDI: Case Development Inspec-
tion
CDM: Climatological Dispersion
Model
CDM: Comprehensive Data
Management
CDMQC: Climatological Disper-
sion Model with Calibration
and Source Contribution
CDNS: Climatological Data
National Summary
CDP: Census Designated Places
CDS: Compliance Data System
CE: Categorical Exclusion. Con-
ditionally Exempt Generator
CEA: Cooperative Enforcement
Agreement
CEA: Cost and Economic As-
sessment
CEAT: Contractor Evidence
Audit Team
CEARC: Canadian Environmen-
tal Assessment Research
Council
CEB: Chemical Element Bal-
ance
CECATS: CSB Existing Chemi-
cals Assessment Tracking
System
CEE: Center for Environmental
Education
CEEM: Center for Energy and
Environmental Management
CEI: Compliance Evaluation
Inspection
CELRF: Canadian Environmen-
tal Law Research Foundation
CEM: Continuous Emission
Monitoring
CEMS: Continuous Emission
Monitoring System
CEPP: Chemical Emergency
Preparedness Plan
CEQ: Council on Environmental
Quality
CERCLA: Comprehensive Envi-
ronmental Response, Com-
pensation, and Liability Act
(1980)
CERCLIS: Comprehensive Envi-
ronmental Response, Com-
pensation, and Liability Infor-
mation System
CERT: Certificate of Eligibility
CF: Conservation Foundation
CFC: Chlorofluorocarbons
CFM: Chlorofluoromethanes
CFR Code of Federal Regula-
tions
CHABA: Committee on Hearing
and Bio-Acoustics
CHAMP: Community Health
Air Monitoring Program
CHEMNET: Chemical Industry
Emergency Mutual Aid Net-
work
CHESS: Community Health and
Environmental Surveillance
System
CHIP: Chemical Hazard Infor-
mation Profiles
CI: Compression Ignition. Confi-
dence Interval
CIAQ: Council on Indoor Air
Quality .
CIBL: Convective Internal
Boundary Layer
CICA: Competition in Contract-
ing Act
CICIS: Chemicals in Commerce
Information System
CIDRS: Cascade Impactor Data
Reduction System
CEMI: Committee on Integrity
and Management Improve-
ment
CIS: Chemical Information Sys-
tem. Contracts Information
System
CLC: Capacity Limiting Constit-
uents
CLEANS: Clinical Laboratory
for Evaluation and Assess-
ment of Toxic Substances
CLEVER Clinical Laboratory
for Evaluation and Validation
of Epidemiologic Research
CLF: Conservation Law Foun-
dation
CLIPS: Chemical List Index and
Processing System
CLP: Contract Laboratory Pro-
gram
CM: Corrective Measure
CMA: Chemical Manufacturers
Association
CMB: Chemical Mass Balance
CME: Comprehensive Monitor-
ing Evaluation
CMEL: Comprehensive Moni-
toring Evaluation Log
CMEP: Critical Mass Energy
Project
CNG: Compresed Natural Gas
COCO: Contractor-Owned/
Contractor-Operated
COD: Chemical Oxygen De-
mand
COH: Coefficient Of Haze
CPF: Carcinogenic Potency Fac-
tor
CPO: Certified Project Officer
CQA: Construction Quality As-
surance
CR: Continuous Radon Monitor-
ing
CROP: Consolidated Rules of
Practice
CRP: Conservation Reserve
Program
CRR: Center for Renewable Re-
sources
CRSTER: Single Source Disper-
sion Model
CSI: Compliance Sampling In-
spection
CSIN: Chemical Substances
Information Network
CSO: Combined Sewer Overflow
CSPA: Council of State Plan-
ning Agencies
CSRL: Center for the Study of
Responsive Law
CTARC: Chemical Testing and
Assessment Research Com-
mission
CTG: Control Techniques
Guidelines
CV: Chemical Vocabulary
CW: Continuous working-level
monitoring
CWA: Clean Water Act (aka
FWPCA)
CWAP: Clean Water Action
Project
CWTC: Chemical Waste
Transportation Council
CZMA: Coastal Zone Manage-
ment Act
CZARA: Coastal Zone Manage-
ment Act ^authorization
Amendments
DAPSS: Document and Person-
nel Security System (IMD)
DCI: Data Call-in
DCO: Delayed Compliance Or-
der
DCO: Document Control Officer
DDT: DichloroDiphenyl-
Trichloroethane
DERs: Data Evaluation Records
DES: Diethylstilbesterol
DI: Diagnostic Inspection
DMR Discharge Monitoring
Report
DNA: Deoxyribonucleic acid
DO: Dissolved Oxygen
DOW: Defenders Of Wildlife
DPA: Deepwater Ports Act
DPD: Method of Measuring
Chlorine Residual in Water
DQO: Data Quality Objective
DRE: Destruction and Removal
Efficiency
DRES: Dietary Risk Evaluation
System
DRMS: Defense Reutilization
and Marketing Service
-------
45
DRR Data Review Record
DS: Diiixotomous Sample*
DSAR Data Self Auditing Pro-
gram
DSCF: Dry Standard Cubic Feet
DSCM: Dry Standard Cubic
Meter
DSS: Decision Support System
DSS: Domestic Sewage Study
DT: Detention Time
DT: Detectors (radon) damaged
or lost
DU: Decision Unit. Ducks Un-
limited
DUG: Decision Unit Coordinator
DWEL: Drinking Water Equiva-
lent Level
DWS: Drinking Water Standard
EA: Endangerment Assessment.
Enforcement Agreement.
Environmental Action. Envi-
ronmental Assessment. Envi-
ronmental Audit
EAF: Electric Arc Furnaces
BAG: Exposure Assessment
Group
BAP: Environmental Action
Plan
EAR: Environmental Auditing
Roundtable
EB: Emissions Balancing
EC: EmulBifiable Concentrate
EC: Environment Canada
EC: Effective Concentration
ECA: Economic Community for
Africa
ECAP: Employee Counselling
and Assistance Program
BCD: Electron Capture Detector
ECHH: Electro-Catalytic Hyper-
Heaters
ECL: Environmental Chemical
Laboratory
ECR: Enforcement Case Review
ECRA: Economic Cleanup Re-
sponsibility Act
ED: Effective Dose
EDA: Emergency Declaration
Area
EDB: Ethylene Dibromide
EDC: Ethylene Dichloride
EDD: Enforcement Decision
Document
EDF: RiwiTmmMmt.nl DefOOM
Fund
Retrieval System
EDS: Electronic Data System
EDS: Energy Data System
EDTA: Ethylene Diamine
Triacetic Acid
EDX: Electronic Data Exchange
EDZ: Emission Density Zoning
RRA; Energy and Environmen-
tal Analysis
EECs: Estimated Environmen-
tal Concentrations
EER Excess Emission Report
EERL: Eastern Environmental
Radiation Laboratory
EERU: Environmental Emer-
gency Response Unit
EESI: Environment and Energy
Study Institute
EESL: Environmental Ecologi-
cal and Support Laboratory
EETFC: Environmental Effects,
Transport, and Fate Commit-
tee
EF: Emission Factor
EFO: Equivalent Field Office
EFTC: European Fluorocarbon
Technical Committee
EGR Exhaust Gas Retircula-
tion
EH: Redox Potential
EHC: Environmental Health
Committee
EHS: Extremely Hazardous
Substance
El: Emissions Inventory
EIA: Environmental Impact
Assessment. Economic Impact
Assessment
EIL: Environmental Impair-
ment Liability
EIRc Endangerment Information
Report
EIR: Environmental Impact
Report
EIS: Environmental Impact
Statement
EIS: Environmental Inventory
System
EIS/AS: Emissions Inventory
System/Area Source
EIS/PS: Emissions Inventory
SystenVPoint Source
EKMA: Empirical Kinetic Mod-
eling Approach
EL: Exposure Level
RT-T- Environmental Law Insti-
tute
ELR: Environmental Law Re-
porter
EM: Electromagnetic Conduc-
tivity
EMAP: Environmental Mapping
• and ABsessment Program
EMAS: Enforcement Manage-
ment and Accountability Sys-
tem
EMR: Environmental Manage-
ment Report
RMS- Enforcement Management
System
EMSL: Environmental Moni-
toring Support Laboratory
EMSL: Environmental Moni-
toring Systems Laboratory
EMTS: Environmental Moni-
toring Testing Site
EMTS: Exposure Monitoring
Test Site
EO: Ethylene Oxide
EOC: Emergency Operating
Center
EOF: Emergency Operations
Facility (RTP)
EOF: End Of Pipe
EOT: Emergency Operations
Team
EP: Earth Protectors
EP: Environmental Profile. End-
use Product. Experimental
Product Extraction Procedure
EPAA: Rnvinnrmnmtnl PrOgTBIQS
Assistance Act
EPAAR: EPA Acquisition Regu-
lation!
EPCRA: Emergency Prepared-
ness and Community Right to
Know Act
EPACASR: EPA Chemical Ac-
tivities Status Report
EPCA: Energy Policy and Con-
servation Act
EPD: Emergency Planning Dis-
trict
EPI: Environmental Policy In-
stitute
EPIC: Environmental Photo-
graphic Interpretation Center
EPNL: Effective Perceived
Noise Level *
EPRI: Electric Power Research
Institute
EFTC: Extraction Procedure
Toxicity Characteristic
Eft Electrical Resistivity
ERA: Economic Regulatory
Agency
ERAMS: Environmental Radi-
ation Ambient Monitoring
System
ERC: Emergency Response
Commission
ERC: Emissions Reduction
Credit
ERC: Environmental Research
Center
ERCS: Emergency Response
Cleanup Services
ERDA: Energy Research and
Development Administration
ERD&DAA: Environmental
Research, Development and
Demonstration Authorization
Act
ERL: Environmental Research
Laboratory
ERNS: Emergency Response
Notification System
ERPi Enforcement Response
Policy
ERT: Emergency Response
Team
ERTAQ: ERT Air Quality Model
ES: Enforcement Strategy.
ESA: Endangered Species Act.
Environmentally Sensitive
Area
ESC: Endangered Species Com-
mittee
ESCA: Electron Sp
for Chemical Analysis
ESCAP: Economic and Social
Commission for Asia and the
Pacific
ESECA: Energy Supply and
Environmental Coordination
Act
ESH: Environmental Safety and
Health
ESP: Electrostatic Precipitators
ET: Emissions Trading
ETP: Emissions Trading Policy
ETS: Environmental Tobacco
Smoke
EUP: End-Use Product
EUP: Experimental Use Permit
EWCC: Environmental Work-
force Coordinating Committee
EXAMS: Exposure Analysis
Modeling System
FACA: Federal Advisory
Committee Act
FAN: Fixed Account Number
FATES: FIFRA and TSCA En-
forcement System
FBC: Fluidized Bed Combustion
. FCC: Fluid Catalytic Converter
FCCU: Fluid Catalytic Cracking
Unit
FCO: Federal Coordinating
Officer (in disaster areas)
FCO: Forms Control Officer
FDF: Fundamentally Different
Factors
FDL: Final Determination Let-
ter
FDO: Fee Determination Offi-
cial
FE: Fugitive Emissions
FEDS: Federal Energy Data
System
FEFx: Forced Expiratory Flow
FEIS: Fugitive Emissions In-
formation System
FEL: Frank Effect Level
FEPCA: Federal Environmental
Pesticide Control Act; enacted
as amendments to FIFRA.
FERC: Federal Energy Regula-
tory Commission
FES: Factor Evaluation System
FEV: Forced Expiratory Volume
FEV1: Forced Expiratory Vol-
ume—one second
FEV1: Front End Volatility In-
dex
FF: Federal Facilities
FFAR: Fuel and Fuel Additive
Registration
FFDCA: Federal Food, Drug,
and Cosmetic Act
FFF: Firm Financial Facility
FFFSG: Fossil-Fuel-Fired
Steam Generator
FFIS: Federal Facilities Infor-
mation System
FFP: Firm Fixed Price
FGD: Flue-Gas Desulfurization
FID: Flame lonization Detector
FIFRA: Federal Insecticide,
Fungicide, and Rodentiride
Act
FIM: Friable Insulation Materi-
al
FINDS: Facility Index System
FTP: Final Implementation Plan
FTPS: Federal Information Pro-
cedures System
FIT. Field Investigation Team
FLETC: Federal Law Enforce-
ment Training Center
FLM: Federal Land Manager
FLP: Flash Point
FLPMA: Federal Land Policy
and Management Act
FMAPl Financial Management
Assistance Project
F/M: Food to Microorganism
Ratio
FML: Flexible Membrane Liner
FMP. Facility Management
Plan
FMP: Financial Management
Plan
-------
46
FMS: Financial ' Management
System
FMVCP: Federal Motor Vehicle
Control Program
FOE: Friends Of the Earth
FOIA: Freedom Of Information
Act
FOISD: Fiber Optic Isolated
Spherical Dipole Antenna
FONSI: Finding Of No Signifi-
cant Impact
FORAST: Forest Response to
Anthropogenic Stress
. FP: Fine Particulate
FPA: Federal Pesticide Act
FPAS: Foreign Purchase Ac-
knowledgement Statements
FPD: Flame Photometric Detec-
tor
FPEIS: Fine Particulate Emis-
sions Information System
FPM: Federal Personnel Manu-
al
FPPA: Federal Pollution Pre-
vention Act
FPR: Federal Procurement Reg-
ulation
FPRS: Federal Program Re-
sources Statement
FPRS: Formal Planning and
Supporting System
FR: Federal Register. Final
Rulemaking
FRA: Federal Register Act
FREDS: Flexible Regional Emis-
sions Data System
FRES: Forest Range Environ-
mental Study
FRM: Federal Reference Meth-
ods
FRN: Federal Register Notice.
Final Rulemaking Notice
FRS: Formal Reporting System
FS: Feasibility Study
FSA: Food Security Act
FSS: Facility Status Sheet
FSS: Federal Supply Schedule
FTP: Federal Test Procedure
(for motor .vehicles)
FTS: File Transfer Service
FTTS: FIFRA/TSCA Tracking
System
FUA: Fuel Use Act
FURS: Federal Underground
Injection Control Reporting
System
FVMP: Federal Visibility Moni-
toring Program
FWCA: Fish and Wildlife Coor-
dination Act
FWPCA: Federal Water Pollu-
tion and Control Act (aka
CWA). Federal Water Pollu-
tion and Control Administra-
tion
GAAP: Generally Accepted Ac-
counting Principles
GAC: Granular Activated Car-
bon
GACT: Granular Activated Car-
bon Treatment
GC/MS: Gas Chromatograph/
Mass Spectograph
GCWR: Gross Combination
Weight Rating
GDE: Generic Data Exemption
GEI: Geographic Enforcement
Initiative
GEMS: Global Environmental
Monitoring System
GEMS: Graphical Exposure
Modeling System
GEP: Good Engineering Practice
GFF: Glass Fiber Filter
GFO: Grant Funding Order
GFP: Government-Furnished
Property
GIGS: Grant Information and
Control System
GIS: Geographic Information
Systems
GIS: Global Indexing System
GLC: Gas Liquid Chromatogra-
phy
GLERL: Great Lakes Environ-
mental Research Laboratory
GLNPO: Great Lakes National
Program Office
GLP: Good Laboratory Practices
GLWQA: Great Lakes Water
Quality Agreement
GMCC: Global Monitoring for
Climatic Change
G/MI: Grams per mile
GOCO: Government-Owned/
Contractor-Operated
GOGO: Government-Owned/
Government-Operated
GOP: General Operating Proce-
dures
GOPO: Government-Owned/
Privately-Operated
GPAD: Gaions-per-acre per-day
GPG: Grams-per-Gallon
GPR Ground-Penetrating Ra-
dar
GPS: Groundwater Protection
Strategy
Gft Grab Radon Sampling
GRCDA: Government Refuse
Collection and Disposal Asso-
ciation
GRGL: Groundwater Residue
Guidance Level
GTN: Global Trend Network
GTR Government Transporta-
tion Request
GVP Gasoline Vapor Pressure
GVW: Grow Vehicle Weight
GVWR: Gross Vehicle Weight
Rating
GW: Grab Working-Level Sam-
pling. Groundwater
GWM: Groundwater Monitoring
GWPS: Groundwater Protection
Standard
GWPS: Groundwater Protection
Strategy
H
HA: Health Advisory
HAD: Health Assessment Docu-
ment
HAP: Hazardous Air Pollutant
HAPEMS: Hazardous Air Pol-
lutant Enforcement Manage-
ment System
HAPPS: Hazardous Air Pollut-
ant Prioritization System
HATREMS: Hazardous and
Trace Emissions System
HAZMAT: Hazardous Materials
HAZOP: Hazard and Operabili-
ty Study
HC: Hazardous Constituents
HC: Hydrocarbon
HCCPD: Hexachlorocyclo-
pentadiene
HCP: Hypothermal Coal Process
HDD: Heavy-Duty Diesel'
HDE: Heavy-Duty Engine
HDG: Heavy-Duty Gasoline-
Powered Vehicle
HDPE: High Density Polyethyl-
ene
HOT: Highest Dose Tested in a
study. Heavy-Duty Truck
HDV: Heavy-Duty Vehicle
HEAL: Human Exposure As-
sessment Location
HECC: House Energy and Com-
merce Committee
HEI: Health Effects Institute
HEM: Human Exposure Model-
ing
HEPA: High-Efficiency Particu-
late Air
HERS: Hyperion Energy Re-
covery System
HHE; Human Health and the
Environment
HHV: Higher Heating Value
HI: Hazard Index
HI-VOL: High-Volume Sampler
HIWAY: A Line Source Model
for Gaseous Pollutants
HLRW: High Level Radioactive
Waste
HMIS: Hazardous Materials
Information System
HMS: Highway Mobile Source
HMTA: Hazardous Materials
Transportation Act
HMTft Hazardous Materials
Transportation Regulations
HOC: Halogenated Organic
Carbons
HON: Hazardous Organic
NESHAP
HOV: High-Occupancy Vehicle
HP: Horse Power
HPLC: High-Performance Liq-
uid Chromatography
HPV: High Priority Violator
HQCDO: Headquarters Case
Development Officer
HRS: Hazardous Ranking Sys-
tem
HRUP: High-Risk Urban Prob-
lem
HSDB: Hazardous Substance
DataBase
HSL: Hazardous Substance List
HSWA: Hazardous and Solid
Waste Amendments
HT: Hypothermally Treated
HTP: High Temperature and
Pressure
HVIO: High Volume Industrial
Organic*
HW: Hazardous Waste
HWDMS: Hazardous Waste
Data Management System
HWGTF: Hazardous Waste
Groundwater Task Force
HWGTF: Hazardous Waste
Groundwater Test Facility
HWLT: Hazardous Waste Land
Treatment
HWM: Hazardous Waste Man-
agement
HWRTF: Hazardous Waste Re-
strictions Task Force
HWTC: Hazardous Waste Treat-
ment Council
I
I/A: Innovative/Alternative
LA: Interagency Agreement
IAAC: Interagency Assessment
Advisory Committee
LAG: Interagency Agreement
IAP: Incentive Awards Program.
Indoor Air Pollution
IARC: International Agency for
Research on Cancer
LATDB: Interim Air Toxics Data
Base
IBT: Industrial Biotest Labora-
tory
ICAIR: Interdisciplinary Plan-
ning and Information Re-
search
ICAP: Inductively Coupled Ar-
gon Plasma
ICB: Information Collection
Budget
ICBN: International Commis-
sion on the.Biological Effects
of Noise
ICE: Industrial Combustion
Emissions Model. Internal
Combustion Engine
ICP: Inductively Coupled Plas-
ma
ICR Information Collection Re-
quest
ICRE: Ignitability, Corrosivity,
Reactivity, Extraction
ICRP: International Commis-
sion on Radiological Protec-
tion
ICRU: International Commis
sion of . Radiological Units
and
Measurements
ICS: Incident Command Sys-
tem.
ICS: Institute for Chemical
Studies.
ICS: Intermittent Control Strat-
egies.
ICS; Intermittent Control Sys
tern
ICWM: Institute for Chemical
Waste Management
IDLH: Immediately Dangerous
to Life and Health
IEB: International Environment
Bureau
IEMP: Integrated Environmen-
tal Management Project
IBS: Institute for Environmen-
tal Studies
IFB: Invitation for Bid
IFCAM: Industrial Fuel Choice
Analysis Model
IFIS: Industry File Information
System
IFPP. Industrial Fugitive Pro-
cess Particulate
IFMS: Integrated Financial
Management System
IGCC: Integrated Gasification
Combined Cycle
-------
47
IGCI: Industrial Gas Cleaning
Institute
IIS: Inflationary Impact State-
ment
LJC: International Joint Com-
mission (on Great Lakes)
l/M: Inspection/Maintenance
IMM: Intersection Midblock
Model
IMPACT: Integrated Model of
Plumes and Atmosphere in
Complex Terrain
IMPROVE: Interagency Moni-
toring of Protected Visual
Environment
INPUFF: Gaussian Puff Dis-
persion Model
INT: Intermittent
IOB: Iron Ore Benefication
IOU: Input/Output Unit
IP: Inhalable Particles
IPM: Inhalable Particulate Mat-
ter. Integrated Pest Manage-
ment
IPP: Implementation Planning
Program. Integrated Plotting
Package. Inter-media Priority
Pollutant (document)
IPCS: International Program on
Chemical Safety
IPP: Independent Power Pro-
ducer
IRG: Interagency Review Group
IRLG: Interagency Regulatory
Liaison Group (Composed of
EPA, CPSC, FDA, and OSHA)
IRIS: Instructional Resources
Information System. Integrat-
ed Risk Information System
IRM: Intermediate Remedial
Measures
IRMC: Inter-Regulatory Risk
Management Council
IRP: Installation Restoration
Program
IRPTC: International Register
of Potentially Toxic Chem-
icals
IRR Institute of Resource Re-
covery
IRS: International Referral Sys-
tems
IS: Interim Status
ISAM: Indexed Sequential File
Access Method
ISC: Industrial Source Complex
ISCL: Interim Status Compli-
ance Letter
ISCLT: Industrial Source Com-
plex Long Term Model
ISCST: Industrial Source Com-
plex Short Term Model
ISD: Interim Status Document
ISE: Ion-specific electrode
ISMAP: Indirect Source Model
for Air Pollution
ISPF: (IBM) Interactive System
Productivity Facility
ISS: Interim Status Standards
FTC: Interagency Testing Com-
mittee
IUR Inventory Update Rule
IWC: In-Stream Waste Concen-
tration
IWS: Ionizing Wet Scrubber
JAPCA: Journal of Air Pollution
Control Association
JCL: Job Control Language
JEC: Joint Economic Committee
JECFA: Joint Expert Committee
of Food Additives
JLC: Justification for Limited
Competition
JMPR: Joint Meeting on Pesti-
cide Residues
JNCP: Justification for Non-
Competitive Procurement
JOFOC: Justification for Other
Than Full and Open
Competition
JPA: Joint Permitting Agree-
. ment
JSD: Jackson Structured Design
JSP: Jackson Structured Pro-
gramming
JTU: Jackson Turbidity Unit
LAA: Lead Agency Attorney
LADD: Lowest Acceptable Daily
Dose
LAER Lowest Achievable Emis-
sion Rate
LAI: Laboratory Audit Inspec-
tion
LAMP: Lake Acidification Miti-
gation Project
LC: Lethal Concentration. Liq-
uid Chromatography
LCD: Local Climatological Data
LCL: Lower Control Limit
LCM: Life Cycle Management
LCRS: Leachate Collection and
Removal System
LD: Land Disposal. Light Duty
LD LO: The lowest dosage of a
toxic substance that kills test
organisms.
LDC: London Dumping Conven-
tion
LDCRS: Leachate Detection,
Collection, and Removal Sys-
tem
LDD: Light-Duty Diesel
LDIP: Laboratory Data Integri-
ty Program
LDft Land Disposal Restric-
tions
LDRTF: Land Disposal Restric-
tions Task Force
LDS: Leak Detection System
LOT: Lowest Dose Tested.
Light-Duty Truck
LDV: Light-Duty Vehicle
T.RTJ Lowest Effect Level. Low-
er Explosive Limit
LEP: Laboratory Evaluation-
Program
LEPC: Local Emergency Plan-
ning Committee
LERC: Local Emergency Re-
sponse Committee
LFL: Lower Flammability Limit
LGR Local Governments Reim-
bursement Program
LI: Langelier Index
LIDAft Light Detection and
Ranging
LIMB: Limestone-Injection Mul-
ti-Stage Burner
LLRW: Low Level Radioactive
Waste
LMFBR: Liquid Metal Fast
Breeder Reactor
LOAEL: Lowest-Observed-Ad-
verse-Effect-Level
LUIS: Label Use Information
System
M
MAPSIM: Mesoscale Air Pollu-
tion Simulation Model
MBAS: Methyiene-Blue-Active
Substances
MEP: Multiple Extraction Pro-
cedure
MOE: Margin Of Exposure
MOS: Margin of Safety
MP: Manufacturing-use Product
MP: Melting Point
MFN: Maximum Possible Num-
ber
MRF: Materials Recovery Facili-
ty
MRID: Master Record Identifi-
cation number
MRL: Maximum-Residue Limit
(Pesticide Tolerance)
MSW: Municipal Solid Waste
MTD: Maximum Tolerated Dose
MUP: Manufacturing-Use Prod-
uct
MUTA: Mutagenicity
N
NCWS: Non-Community Water
System
NETA: National Environmental
Training Association
NFRAP: No Further R«m«Hi«l
Action Planned
NICT: National Incident Coordi-
nation Team
NIOSH: National Institute of
Occupational Safety and Health
NIPDWR National Interim
Primary Drinking Water Regu-
lations
NISAC: National Industrial
Security Advisory Committee
NO A: Notice of Arrival
NOAC: Nature of Action Code
NOAEL: No Observable Adverse
Effect Level
NPHAR National Pesticide
Hazard Assessment Program
NSDWft National Secondary
Drinking Water Regulations
NSEC: National System for
Emergency Coordination
NSER National System for
Emergency Preparedness
NSR New Source Review
NTP: National Toxicology Pro-
gram
NTNCWS: Non-Transient Non-
Community Water System
NTU: Nephlometric Turbidity
Unit
o
OCD: Offshore and Coastal
Dispersion
OF: Optional Form
OLTS: On Line Tracking Sys-
tem
O&M: Operations and Mainte-
nance
ORM: Other Regulated Material
ORP: Oxidation-Reduction Po-
tential
PA1: Performance Audit Inspec-
tion (CWA)
PAI: Pure Active' Ingredient
compound
PAM: Pesticide Analytical Man-
ual
PAT: Permit Assistance Team
(RCRA)
PATS: Pesticide Action Tracking
System
PATS: Pesticides Analytical
Transport Solution
PBA: Preliminary Benefit Anal-
ysis (BEAD)
PCA: Principle Component
Analysis
PCM: Phase Contrast Micros-
copy
PCN: Policy Criteria Notice
PCO: Pest Control Operator
PDCI: Product Data Call-In
PFCRA: Program Fraud Civil
Remedies Act
PHC: Principal Hazardous Con-
stituent
PHSA: Public Health Service
Act
PI: Preliminary Injunction. Pro-
gram Information
PIC: Products of Incomplete
Combustion
PIGS: Pesticides in Groundwa-
ter Strategy
PIMS: Pesticide Incident Moni-
toring System
PIN: Pesticide Information Net-
work
PIN: Procurement Information
Notice
PIP: Public Involvement Pro-
gram
PIPQUIC: Program Integration
Project Queries Used in Inter-
active Command
PIRG: Public Interest Research
Group
PIRT: Pretreatinent Implemen-
tation Review Task Force
PITS: Project Information
Tracking System
PLJRRA: Pollution Liability
Insurance and Risk Retention
Act
PLM: Polarized Light Micros-
copy
PLUVUE: Plume Visibility Mod-
el
PM: Particulate Matter
PM10: Particulate Matter
(nominally 10m and less)
PM15: Particulate Matter
(nominally 16m and leas)
PMEL: Pacific Marine Environ-
mental Laboratory
FMN: Premanufacture Notifi-
cation
PMNP: Premanufacture Noti-
fication Form
-------
48
PMR- Pollutant Mass Rate
PMRS: Performance Manage-
ment and Recognition System
PMS: Program Management
System
PNA: Polynuclear Aromatic
Hydrocarbons
PO: Project Officer
POC: Point Of Compliance
POE: Point Of Exposure
POGO: Privately-Owned/ Gov-
ernment-Operated
POHC: Principal Organic Haz-
ardous Constituent
POI: Point Of Interception
POLREP:Pollution Report
POM: Particulate Organic Mat
ter. Polycyclic Organic Matter •
FOR: Program of Requirements
POTW: Publicly Owned Treat-
ment Works
POV: Privately Owned Vehicle
PP: Program Planning
PPA: Planned Program Accom-
plishment
PPB: Parts Per Billion
PPIC: Pesticide Programs Infor-
mation Center
PPIS: Pesticide Product Infor-
mation System
PPM/PPB: Parts per million/
parts per billion
PPMAP: Power Planning Model-
ing Application Procedure
PPSP: Power Plant Siting Pro-
gram
PPT: Parts Per Trillion
PPTH: Parts Per Thousand
PQUA: Preliminary Quantita-
tive Usage Analysis
PR- Preliminary Review
PRAj Paperwork Reduction Act
PRA: Planned Regulatory Ac'
tion
PRATS: Pesticides Regulatory
Action Tracking System
PRC: Planning Research Cor-
poration
PRI: Periodic Reinvestigation
PRM: Prevention Reference
Manuals
PRN: Pesticide Registration
Notice
PRP: Potentially Responsible
Party
PRZM: Pesticide Root Zone
Model
PS: Point Source
PSAM: Point Source Ambient
Monitoring
PSC: Program Site Coordinator
PSD: Prevention of Significant
Deterioration
PSES: Pretreatment Standards
for ESri«*ir»g Sources
PSI: Pollutant Standards Index
PSI: Pounds Per Square Inch
PSI: Pressure Per Square Inch
PSIG: Pressure Per Square Inch
Gauge
PSM: Point Source Monitoring
PSNS: Pretreatment Standard*
for New Sources
PSU: Primary Sampling Unit
PTDIS: Single Stack Meteoro-
logical NIodel in EPA
UNAMAP Series
PTE: Potential to Emit
PTFE: Polytetrafluoroethylene
(Teflon)
PTMAX: Single Stack Meteoro-
logical Model in EPA
UNAMAP series
PTPLU: Point Source Gaussian
Diffusion Model
PUC: Public Utility Commission
PV: Project Verification
PVC: Polyvinyl Chloride
PWS: Public Water Supply/
System
PWSS: Public Water Supply
System
QAC: Quality Assurance Coordi-
nator.
QA/QC: Quality Assistance/
Quality Control
QAMIS: Quality Assurance
Management and Information
System
QAO: Quality Assurance Officer
QAPP: Quality Assurance Pro-
gram (or Project) Plan
QAT: Quality Action Team
QBTU: Quadrillion British
Thermal Units
QC: Quality Control
QCA: Quiet Communities Act
QCI: Quality Control Index
QCP: Quiet Community Pro-
gram
QNCR Quarterly Noncompli-
ance Report
QUA: Qualitative Use Assess-
ment
QUIPE: Quarterly Update for
Inspector in Pesticide En-
forcement
RA: Reasonable Alternative.
Regulatory Alternatives.
Regulatory Analysis. Remedi
al Action. Resource Alloca
tion. Risk Analysis. Risk
Assessment
RAATS: RCRA Administrate
Action Tracking System
RAG: Radiation Advisory Com-
mittee
RAC: Regional Asbestos Coor-
dinator
RAC: Response Action Coordi-
nator
RACM: Reasonably Available
Control Measures
RACT: Reasonably Available
Control Technology
RAD: Radiation Adsorbed Dose
(unit of measurement of radi-
ation absorbed by humans)
RADM: Random Walk Advec-
tion and Dispersion Model
RADM: Regional Acid Deposi-
tion Model
RAM: Urban Air Quality Model
for Point and Area Source in
EPA UNAMAP Series
RAMP: Rural Abandoned Mine
Program
RAMS: Regional Air Monitoring
System
RAP: Radon Action Program
RAP: Reregistration Assessment
Panel
RAP: Remedial Accomplishment
Plan
RAP: Response Action Plan
RAPS: Regional Air Pollution
Study
RARG: Regulatory Analysis
Review Group
RAS: Routine Analytical Service
RAT: Relative Accuracy Test
RB: Request for Bid
RC: Responsibility Center
RCC: Radiation Coordinating
Council
RCDO: Regional Case Develop-
ment Officer
RCO: Regional Compliance Offi-
cer
RCP: Research Centers Program
RCRA: Resource Conservation
and Recovery Act
RCRIS: Resource Conservation
and Recovery Information
System
RD/RA: Remedial Design/ Re-
medial Action
R&D: Research and Develop-
ment '
RD&D: Research, Development
and Demonstration
RDF: Refuse-Derived Fuel
rDNA: Recombinant DNA
RDU: Regional Decision Units
RDV: Reference Dose Values
RE: Reasonable Efforts
RE: Reportable Event
REAP: Regional Enforcement
Activities Plan
REE: Rare Earth Elements
REEP: Review of Environmen-
tal Effects of Pollutants
REM (Roentgen Equivalent
Man)
REM/FIT: Remedial/Field Inves-
tigation Team
REMS: RCRA Enforcement
Management System
REP: Reasonable Efforts Pro-
gram
REPS: Regional Emissions Pro-
jection System
RESOLVE: Center for Environ-
mental Conflict Resolution
RF: Response Factor
RFA: Regulatory Flexibility Act
RFB: Request for Bid
RFD: Reference Dose Values
RFI: Remedial Field Investiga-
tion
RFP: Reasonable Further Pro-
grams. Request for Proposal
RHRS: Revised Hazard Ranking
System
RI: Reconnaissance Inspection
RI: Remedial Investigation
RIA: Regulatory Impact Anal-
ysis
RIA: Regulatory Impact Assess-
ment
RIC: Radon Information Center
RICC: Retirement Information
and Counseling Center
RICO: Racketeer Influenced and
Corrupt Organizations Act
RI/FS: Remedial Information/
Feasibility Study
RIM: Regulatory Interpretation
Memorandum
RIN: Regulatory Identifier
Number
RIP: RCRA Implementation
Plan
RISC: Regulatory Information
Service Center
RJE: Remote Job Entry
RLL: Rapid and Large Leakage
(Rate)
RMCL: Recommended Maxi-
mum Contaminant Level
(this phrase being discontin-
ued in favor of MCLG)
RMDHS: Regional Model Data
Handling System
RMIS: Resources Management
Information System
RNA: Ribonucleic Acid
ROADCHEM: Roadway Version
that Includes Chemical Reac-
tions of BI,NO2, andO3
ROADWAY: A Model to Predict
Pollutant Concentrations
Near a Roadway
ROC: Record Of Communication
RODS: Records Of Decision
System
ROG: Reactive Organic Gases
ROLLBACK: A Proportional
Reduction Model
ROM: Regional Oxidant Model
ROMCOE: Rocky Mountain
Center on Environment
ROP: Regional Oversight Policy
ROPA: Record Of Procurement
Action
RP: Radon Progeny Integrated
Sampling. Respirable
Participates. Responsible
Party
RPAR Rebuttable Presumption
Against Registration
RPM: Reactive Plume Model.
Remedial Project Manager
RQ: Reportable Quantities
RRC: Regional Response Center
RRT: Regional Response Team
RRT: Requisite Remedial
Technology
RS: Registration Standard
RSCC: Regional Sample Control
Center
RSD: Risk-Specific Dose
RSE: Removal Site Evaluation
RTCM: Reasonable Transpor-
tation Control Measure
RTDM: Rough Terrain Diffusion
Model
RTECS: Registry of Toxic Ef-
fects of Chemical Substances
RTM: Regional Transport Model
RUP: Restricted Use Pesticide
RVP: Reid Vapor Pressure
RWC: Residential Wood Com-
bustion
S&A: Sampling and Analysis.
Surveillance and Analysis
SAB: Science Advisory Board
SAC: Suspended and Cancelled
Pesticides
-------
49
SAEWG: Standing Air Emis-
sions Work Group
SAIC: Spetial-Agenta-In-Charge
SAIP: Systems Acquisition and
Implementation Program
SAMWG: Standing Air Moni-
toring Work Group
SANE: Sulfur and Nitrogen
Emissions
SANSS: Structure and Nomen-
clature Search System
SAP. Scientific Advisory Panel
SAR Start Action Request.
Structural Activity Relation-
ship (of a qualitative assess-
ment) .
SARA: Superfund Amendments
and Reauthorization Act- of,
1986
SAROAD: Storage and Retrieval
Of Aerometric Data
SAS: Special Analytical Service.
Statistical Analysis System
SASS: Source Assessment Sam-
pling System
SAV: Submerged Aquatic Vege
tation
SC: Sierra Club
SOAP: Superfund Consolidated
Accomplishments Plan
SCBA: Self-Contained Breath-
ing Apparatus
SCC: Source Classification Code
SCD/SWDC: Soil or Soil and
Water Conservation District
SCFM: Standard Cubic Feet Per
Minute
SCLDF: Sierra Club Legal De-
fense Fund
SCR: Selective Catalytic Reduc-
tion
SCRAM: State Consolidated
RCRA Authorization Manual
SCRC: Superfund Community
Relations Coordinator
SCS: Supplementary Control
Strategy/System
SCSA: Soil Conservation Society
of America
SCSP: Storm and Combined
Sewer Program
SCW: Supercritical Water Oxi-
dation
SDC: Systems Decision Plan
SDWA: Safe Drinking Water
Act
SEA: State Enforcement
Agreement
SEA; State/EPA Agreement
SEAM: Surface, Environment,
and Mining
SEAS: Strategic Environmental
Assessment System
SEIA: Socioeconomic Impact
Analysis
SEM: Standard Error of the
Means
SEP: Standard Evaluation Pro-
cedures
SEPWC: Senate Environment
and Public Works Committee
SERC: State Emergency Plan-
ning Commission
SES: Secondary Emissions
Standard
SETS: Site Enforcement Track-
ing System
SF: Standard Form. Superfund
SFA: Spectral Flame Analyzers
SFDS: Sanitary Facility Data
System
SFFAS: Superfund Financial
Assessment System
SFIREG: State FIFRA Issues
Research and Evaluation
Group
SFS: State Funding Study
SHORTZ: Short Term Terrain
Model
SHWL: Seasonal High Water
Level
SI: International System of
Units. Site Inspection. Sur-
veillance Index. Spark Igni-
tion
SIC: Standard Industrial Classi-
fication
SICEA: Steel Industry Compli-
ance Extension Act
SIMS: Secondary Ion-Mass
Spectrometry
SIP: State Implementation Plan
SITE: Superfund Innovative
Technology Evaluation
SLAMS: State/Local Air Moni-
toring Station
SLSM: Simple Line Source Mod-
el
SMART: Simple Maintenance of
ARTS
SMCL: Secondary Maximum
Contaminant Level
SMCRA: Surface Mining Con-
trol and Reclamation Act
SME: Subject Matter Expert
SMO: Sample Management
Office
SMOA: Superfund Memoran-
dum of Agreement
SMSA: Standard Metropolitan
Statistical Area
SNA: System Network Architec-
ture
SNAAQS: Secondary National
Ambient Air Quality Stan-
dards
SNAP: Significant Noncompli-
ance Action Program
SNARL: Suggested No Advene
Response Level
SNC: Significant Noncomplien
SNUR Significant New Use
Rule
SOC: Synthetic Organic Chem-
icals
SOCMI: Synthetic Organic
Chemicals Manufacturing
Industry
SOTDAT: Source Test Data
SOW: Scope Of Work
SPAR: Status of Permit Applica-
tion Report
SPCC: Spill Prevention, Con-
tainment, and Countermea-
sure
SPE: Secondary Particulate
Emissions
SPF: Structured Programming
Facility
SPI: Strategic Planning Initia-
tive
SPLMD: Soil-pore Liquid Moni-
toring Device
SPMS: Special Purpose Moni-
toring Stations
SPMS: Strategic Planning and
Management System
SPOC: Single Point Of Contact
SPS: State Permit System
SPSS: Statistical Package for
the Social Sciences
SPUR Software Package for
Unique Reports
SQBE: Small Quantity Burner
Exemption
SQG: Small Quantity Generator
SRAP: Superfund Remedial
Accomplishment Plan
SRC: Solvent-Refined Coal
SRM: Standard Reference Meth-
od
SRP: Special Review Procedure
SRR Second Round Review.
Submission Review Record
SRTS: Service Request Tracking
System
SS: Settleable Solids. Superfund
Surcharge. Suspended Solids
SSA: Sole Source Aquifer
SSAC: Soil Site Assimilated
Capacity
SSC: State Superfund Contracts
SSD: Standards Support Docu-
ment
SSEIS: Standard Support and
Environmental Impact
Statement. Stationary Source
Emissions and Inventory
System
SSI: Size Selective Inlet
SSMS: Spark Source Mass Spec-
trometry
SSO: Source Selection Official
SSTS: Section Seven Tracking
System
SSURO: Stop Sale, Use and
Removal Order
STAPPA: State and Territorial
Air Pollution
STALAPCO: State and Local
Air- Pollution Control Offi-
cials
STAR: Stability Wind Rose.
State Acid Rain Projects
STEL: Short Term Exposure
Limit
STEM: Scanning Transmission-
Electron Microscope
STN: Scientific and Technical
Information Network
STORET: Storage and Retrieval
of Water-Related Data
STP: Sewage Treatment Plant.
Standard Temperature and
Pressure
SUP: Standard Unit of Process-
ing
SURE: Sulfate Regional Experi-
ment Program
SV: Sampling Visit
SW: Slow Wave
SWC: Settlement With Condi-
tions
SWDA: Solid Waste Disposal
Act
SWIE: Southern Waste Infor-
mation Exchange
SWMU: Solid Waste Manage-
ment Unit
SWTR Surface Water Treat-
ment Rule.
SYSOP: Systems Operator
TAG: Technical Assistance
Grant
TALMS: Tunable Atomic Line
Molecular Spectroscopy
TAMS: Toxic Air Monitoring
System
TAMTAC: Toxic Air Monitoring
System Advisory Committee
TAP: Technical Assistance Pro-
gram
TAPDS: Toxic Air Pollutant
Data System
TAS: Tolerance Assessment
System
TBT: Tributyltin
TC: Target Concentration. Tech-
nical Center. Toxicity Charac-
teristics. Toxic Concentration:
TCDD: Dioxin (Tetrachlorodi-
benzo-p-dioxin)
TCDF: Tetrachlorodi-benzo-
furans
TCE: Trichloroethylene
TCLP: Total Concentrate
Leachate Procedure. Toxicity
Characteristic Leachate Pro-
cedure
TCM: Transportation Control
Measure
TCP: Transportation Control
Plan. Trichloroethylene.
Trichloropropane
TCRI: Toxic Chemical Release
Inventory
TD: Toxic Dose
TDS: Total Dissolved Solids
TEAM: Total Exposure Assess-
ment Model
TEC: Technical Evaluation
Committee
TEG: Tetraethylerie Glycol
TEGD: Technical Enforcement
Guidance Document
TEM: Texas Episodic Model
TEP: Typical End-use Product.
Technical Evaluation Panel
TERA: TSCA Environmental
Release Application
TES: Technical Enforcement
Support
TEXIN: Texas Intersection Air
Quality Model
TOO: Total Gross Output
TGAI: Technical Grade of the
Active Ingredient
TCP: Technical Grade Product
THC: Total Hydrocarbons
THM: Trihalomethane
TI: Temporary Intermittent
TI: Therapeutic Index
TIBL: Thermal Internal
Boundary Layer
TIC: Technical Information
Coordinator. Tentatively
Identified Compounds
TIM: Technical Information
Manager
TIP: Transportation Improve-
ment Program
TIS: Tolerance Index System
TISE: Take It Somewhere Else
TTTC: Toxic Substance Control
Act Interagency Testing Com-
mittee
TLV: Threshold Limit Value
TLV-C: TLV-Ceiling
-------
50
TLV-STEL: TLV-Short Term
Exposure Limit
TLV-TWA: TLV-Time Weighted
Average
TMRC: Theoretical Maximum
Residue Contribution
TNCWS: Transient Non-Com-
munity Water System
TNT: Trinitrotoluene
TO: Task Order
TOA: Trace Organic Analysis
TOG: Total Organic Carbon/
Compound
TOX: Tetradichloroxylene
TP: Technical Product
TPC: Testing Priorities Com-
mittee
TPI: Technical Proposal Instruc-
tions
TPQ: Threshold Planning Quan-
tity
TPSIS:Transportation Planning
Support Information System
TFTH: Triphenyltinhydroxide
TPY: Tons Per Year
TQM: Total Quality Manage-
ment
T-R: Transformer-Rectifier
TRC: Technical Review Com-
mittee
TRD; Technical Review Docu-
ment
TRI: Toxic Release Inventory
TRIP. Toxic Release Inventory
Program
TRIS: Toxic Chemical Release
Inventory System
TRLN: Triangle Research Li-
brary Network
TRO: Temporary Restraining
Order
TSA: Technical Systems Audit
TSCA: Toxic Substances Control
Act '
TSCATS: TSCA Test Submis-
sions Database'
TSCC: Toxic Substances Coordi-
nating Committee
TSD: Technical Support Docu-
ment
TSDF: Treatment, Storage, and
Disposal Facility
TSDG: Toxic Substances Dia-
logue Group
TSI: Thermal System Insulation
TSM: Transportation System
Management
TSO: Time Sharing Option
TSP Total Suspended Particu-
lates
TSS: Total Suspended (non-fil-
terable) Solids
TTFA: Target Transformation
Factor Analysis
TTHM: Total Trihalomethane
TTO: Total Toxic Organics
TTY: Teletypewriter
TVA: Tennessee Valley Authori-
ty
TWA: Time Weighted Average
TWS: Transient Water System ,
TZ: Treatment Zone
u
UAC: User Advisory Committee
UAM: Urban Airshed Model
UAO: Unilateral Administrative
Order
UAPSP Utility Acid Precipita-
tion Study Program
UAQI: Uniform Air Quality
Index
UARG: Utility Air Regulatory
Group
UCC: Ultra Clean Coal
UCCI: Urea-Formaldehyde
Foam Insulation
UCL: Upper Control Limit
UDMH: Unsymmetrical Di-
methyl Hydrazine
UEL: Upper Explosive Limit
UFL: Upper Flammability Limit
UIC: Underground Injection
Control
UMTRCA: Uranium Mill Tail-
ings Radiation Control Act
UNAMAP. Users' Network for
Applied Modeling of Air Pol-
lution
UNEP United Nations Environ-
ment Program
USC: Unified Soil Classification
USDW: Underground Sources of
Drinking Water
USFS: United States Forest
Service
USP U.S. Pharmacopeia
UST: Underground Storage
Tank
UTM: Universal Transverse
Mercator
UTP Urban Transportation
Planning
UV: Ultraviolet
UZM: Unaaturated Zone Moni-
toring
VALLEY: Meteorological Model
to Calculate Concentrations
on Elevated Terrain
VCM: Vinyl Chloride Monomer
VE: Visual Emissions
VEO: Visible Emission Observa-
tion :
VHS: Vertical and Horizontal
Spread Model
VHT: Vehicle-Hours of Travel
VISTTA: Visibility WmiTnumt
from Sulfur Transformation
and Transport in the Atmo-
sphere
VKT: Vehicle Kilometers Trav-
eled
VMT: Vehicle Miles Traveled
VOC: Volatile Organic Com-
pounds
VOS: Vehicle Operating Survey
VOST: Volatile Organic Sam-
pling Train
VP. Vapor Pressure
VSD: Virtually Safe Dose
VSI: Visual Site Inspection
VSS: Volatile Suspended Solids
w
WA: Work Assignment
WADTF: Western Atmospheric
Deposition Task Force
WAP: Waste Analysis Plan
WB: Wet Bulb
WCED: World Commission on
Environment and Develop-
ment
WDROP: Distribution Register
of Organic Pollutants in Wa-
ter
WENDB: Water Enforcement
National Data Base
WERL: Water Engineering Re-
search Laboratory
WHO: World Health Organi-
zation
WHWT: Water and Hazardous
Waste Team
WICEM: World Industry Con-
ference on Environmental
Management
WL: Warning Letter
WL: Working Level (radon mea-
surement)
WLA/TMDL: Wasteload Alloca-
tion/Total Maximum Daily
Load
WLM: Working Level Months
WMO: World Meteorological
Organization
WPCF: Water Pollution Control
Federation
WQS: Water Quality Standard
WRC: Water Resources Council
WRDA: Water Resources Devel-
opment Act
WRI: World Resources Institute
WS: Work Status
WSF: Water Soluble Fraction
WSRA: Wild and Scenic Rivers
Act
WSTB: Water Sciences and
Technology Board
WSTP Wastewater Sewage
Treatment Plant
WWEMA: Waste and Waste-
water Equipment Manufac-
turers Association
WWF: World Wildlife Fund
WWTPi Wastewater Treatment
Plant
WWTU: Wastewater Treatment
Unit
ZHE: Zero Headspace Extractor
ZOI: Zone Of Incorporation
ZRL: Zero Risk Level
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