svEPA
United States
Environmental Protection
Agency
Communications, Education,
And Public Affairs
(1704)
EPA 175-B-97-001
December 1997
www. epa.gov
Terms Of Environment
Glossary, Abbreviations, and
Acronyms
(Revised December 1997)
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Introduction
Terms of Environment defines in non-technical language the more
commonly used environmental terms appearing in EPA publications, news
releases, and other Agency documents available to the general public,
students, the media, and Agency employees. The definitions do not
constitute the Agency's official use of terms for regulatory purposes, and
nothing in this document should be constructed to alter or supplant any
other federal document. Official terminology may be found in the laws and
related regulations as published hi such sources as the Congressional
Record, Federal Register, and elsewhere.
The terms selected for inclusion are derived from previously published
lists, internal glossaries: produced by various programs and specific
suggestions made by personnel hi many Agency offices. The chemicals and
pesticides selected for inclusion are limited to those most frequently
referred to in Agency publications or that are the subject of major
regulatory or program activities. v
Definitions or information about substances or program activities not
included herein may be found in EPA libraries or scientific/technical
reference documents, or may be obtained from various program offices.
Those with suggestions for future editions should write to the Office of
Communications, Education, and Public Affairs, 1704, USEPA,
Washington, DC 20460-0001.
\ •>- ' '•.',. •.' - "• ' • ' .
Also available on http: //www. epa. gov/OCEPAterms.
Abbreviations and acronyms list begins on page 51
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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,
Abatement Debris: Waste from
remediation activities. ,
Absorbed Dose: In exposure assessment,
the amount of a substance that penetrates
an exposed organism's absorption barri-
ers (e.g.,, skin, lung tissue, gastrointesti-
nal tract) through physical or.biological
processes. The term is synonymous with
internal dose.
Absorption: The uptake of water , other
fluids, or dissolved chemicals by a cell or
an organism (as tree roots absorb
dissolved nutrients in soil.)
Absorption Barrier: Any of the exchange
sites of the body that permit uptake of
various substances at different rates (e.g.,
skin, lung tissue, and gastrointestinal-
tract wall) . • • -
Accident Site:The location of an unexpect-
ed occurrence, failure or loss, either at a
plant or along a transportation route,
resulting in a release of hazardous
materials.
Acclimatization: The physiological and
behavioral adjustments of an organism to
changes in its environment. '
Acid Aerosol: Acidic liquid or solid
particles small enough to become air-
borne. High concentrations can irritate the
lungs and have been .associated with
respiratory diseases like asthma'.
Acid Deposition: A complex chemical
and atmospheric phenomenon that occurs
when emissions of sulfur and nitrogen
compounds and other substances are
transformed by chemical processes in the
atmosphere, often far from the original
sources, and then deposited 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 particulates.
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 a base (e.g., water or soil) to,
resist changes i'n 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
t recommended by EPA for enforcement by
FDA and USDA when pesticide residues
occur in food or feed commodities for
reasons other than the direct application
of the pesticide. As opposed to "toler-
ances" which are established for residues
occurring as a direct result 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
contaminant concentration in the environ-
ment high enough to warrant action or
trigger a response under SARA and the
National Oil and Hazardous Substances
Contingency Plan. The term is also used in
other regulatory programs. (See: toleranc-
es.) ' . . .
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 drinking water. It is also used in
motor vehicle evaporative control sys-
tems. . .
Activated Sludge: Product that results
when primary effluent is mixed with
bacteria-laden sludge and then agitated
and aerated to promote biological treat-
ment, speeding the breakdown of organic
matter in raw sewage undergoing second-
ary waste treatment.
Activator: A chemical added to a pesticide
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 A gency
(LEA) will follow in performing the initial
and additional cleaning, operation and
maintenance-program tasks; periodic sur-
veillance; and reinspection required by
the Asbestos Hazard Emergency Re-
sponse Act (AHERA).
Acute Exposure: A single exposure to ,a
toxic substance which may result in severe
biological harm or death. Acute exposures
are usually characterized as lasting no
longer than a day, as compared to longer,
continuing exposure over a period of .time.
Acute Toxicity: The ability of a substance
to cause severe biological harm or death
soon after a single exposure or dose. Also,
any poisonous effect resulting from a
single short-term exposure to a toxic
substance. (See: chronic toxicity, toxicity.) ,
Adaptation: Changes in an organism's
physiological structure or function or
habits that allow it to survive in new
surroundings.
Add-on Control Device: Art air pollution
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 con-
trolled 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.
Administered Dose: In exposure assess-
ment, the amount of a substance given to a
test subject (human or animal) to
determine dose-response relationships.
Since exposure to chemicals is usually
inadvertent, this quantity is often called •
. potential dose.
Administrative Order: A legal document
signed by EPA directing an individual,
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 enforced 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 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 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 Super-
. fund site, culminating in the record of
, decision for remedial action or, an action
memorandum for removal actions.
Adsorption: Removal of a pollutant from
air or water by collectin'g the pollutant on
the surface of a solid material; e.g., an
advanced method of treating waste in
which activated carbon removes organic
matter from waste-water. . •
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 quality
stated on its label. 2. A food, feed, or
product that contains illegal pesticide •
residues. •
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Advanced Wastewater Treatment: Any
treatment of sewage that goes beyond the
secondary or biological water treatment
stage and includes the removal of
nutrients such as phosphorus and nitro-
gen and a high percentage of suspended
solids. (See primary, secondary treat-
ment,)
Adverse Effects Data: FIFRA requires a
pesticide registrant to submit data to EPA
on any studies or other information
regarding unreasonable^dverse effects of
a pesticide at-any time after its registra-
tion.
Advisory: A non-regulatory document
that communicates risk information to
those who may have to make risk
management decisions.
Aerated Lagoon: A holding and/or
treatment pond that speeds up the natural
process of biological decomposition- of
organic waste by stimulating the growth
and activity of bacteria that degrade
organic waste.
Aeration: A process which promotes
biological degradation of organic matter
in water. The process may be passive (as
when waste is exposed to air), or active (as
when a mixing or bubbling device
introduces the air).
Aeration Tank: A chamber used to inject
air into water.
Aerobic: Life or processes that require, or
are not destroyed by, the presence of
oxygen. (See: anaerobic.)
Aerobic Treatment Process by which
microbes decompose complex organic
compounds in the presence of oxygen and
use the liberated-energy for reproduction
and growth. (Such processes include
extended aeration, trickling filtration, and
rotating biological contactors.)
Aerosol: 1. Small droplets or particles
suspended in the atmosphere, typically
containing sulfur. They are usually
emitted naturally (e.g., in volcanic erup-
tions) and as the result of anthropogenic
(human) activities such as burning fossil
fuels. 2. The pressurized gas used to
propel substances out of a container.
Affected Landfill: Under the Clean Air
Act, landfills that meet criteria for
capacity, age, and emissions rates set by
the EPA. They are required to collect and
combust their gas emissions.
Affected Public: l.The people who live
and/or work near a hazardous waste site.
2, The human population adversely
impacted following exposure to a toxic
pollutant in food, water, air, or soil.
Afterburner: In incinerator technology, a
burner located so that the combustion
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 concentration for feed
to a chemical feeder. Also called a-day
tank.
Agent: Any physical, chemical, or biologi-
cal entity that can be harmful to an
organism(synonymous with stressor).
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 pes-
ticides and fertilizers; erosion and .dust
from plowing; improper disposal of
animal manure and carcasses; crop
residues, and debris.
Agroecosystem: 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 Education
Agency to ensure that the AHERA
requirements for asbestos management
and abatement are properly implement-
ed.
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 the air in
the house will be replaced in a one-hour
period.
Air Cleaning: Indoor-air quality-control
strategy to remove various airborne1
particulates and/or gases from the air.
Most common methods are particulate
filtration, electrostatic precipitation, and
gas sorption.
Air Contaminant: Any particulate matter,
gas, or combination thereof, other than
water vapor. (See: air pollutant.)
Air Curtain: A method of containing oil
spills. Air bubbling through a perforated
pipe causes an upward water flow that
slows the spread of oil. It can also be used
to stop fish from entering polluted water.
Air Exchange Rate: The rate at Which
outside air replaces-indoor air in a given
space.
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 back siphonage.
Air Handling Unit: Equipment that
includes a fan or blower, heating and/or
cooling coils, regulator controls, conden-
sate drain pans, and air filters.
Air Mass: A large volume of air with
certain meteorological or polluted charac-
teristics—e.g., a heat inversion or smoggi-
ness—while in one location. The character-
istics can change as the air mass moves
away.
Air Monitoring: (See: monitoring)
Air/Oil Table: The surface between the
vadose zone and ambient oil; the pressure,
of oil in the porous medium is equal to
atmospheric pressure.
Air Padding: Pumping dry air into a
container to assist with the withdrawal of
liquid or to force a liquefied gas such as
chlorine out of the container.
Air Permeability: Permeability of soil
with respect to air. Important to the design
of soil-gas surveys. Measured in darcys or
centimeters-per-second.
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 concentration,
harm man, other animals, vegetation, or
material. Pollutants may include 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. Generally, they fall into two main
groups: (1) those emitted directly from
identifiable sources and (2) those pro-
duced in the air by interaction between
two or more primary pollutants, or by
reaction with normal atmospheric constitu-
ents, with or without photoactivation.
Exclusive of pollen, fog, and dust, which
are of natural origin, about 100 contami-
nants have been identified. Air pollutants
are often grouped in categories for ease in
classification; some of he categories are:
solids, sulfur compounds, volatile organic
chemicals, particulate matter, nitrogen
compounds, oxygen compounds, halogen
compounds, radioactive compound, and
odors.
Air Pollution: The presence of contami-
nants or pollutant substances in the-air
that interfere with human health or
welfare, or produce other harmful envi-
ronmental effects.
Air Pollution 'Control Device: Mecha-
nism or equipment that cleans emissions
generated by a source (e.gv an incinerator,
industrial smokestack, or an automobile
exhaust system) by removing pollutants
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\vo-u\d otherwise be released to the
atmosphere. . .
Air Pollution Episode: A period of
abnormally high concentration of air
pollutants, often due to low winds and
temperature inversion, that can cause
illness and death. (See: episode, pollu-
tion.)
"Air Quality Control Region: Federally
designated area that is required to meet
and maintain federal ambient air quality
standards. May include nearest states that
share common air pollution problems.
Air Quality Standards: The level of
pollutants prescribed by regulations that
are not be exceeded during a given time in
a defined area. .
Air Quality Criteria: The levels of
pollution -and lengths of exposure above
which 'adverse health and welfare effects
may occur.
Air Sparging: Injecting air or oxygert into
an aquifer to strip or flush Volatile
contaminants as air bubbles up through
The ground water and is captured by a
vapor extraction system.
Air Stripping: A treatment system that
removes volatile "organic compounds
(VOCs) from contaminated ground water
or surface water by forcing an airstream
through the water and causing the
compounds to evaporate.
Air Toxics: Any air pollutant for which a
national ambient air quality standard
(NAAQS) does not exist (i.e., excluding
ozone, carbon monoxide, PM-10, sulfur
dioxide, nitrogen oxide) that may reason-
ably be anticipated to cause cancer;
respiratory, cardiovascular, or ;develop-
mental effects; reproductive dysfunctions,
neurological disorders, 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 droplets.
Chemical composition of particulates
varies widely, depending on location and
time of year. Sources of airborne particu-
lates include: dust, emissions from
industrial processes, combustion prod-
ucts from the burning of wood and coal,
combustion products" associated with
motor vehicle or non-road engine ex-
hausts, and reactions to gases in the
atmosphere. . , ' - .
Airborne Release: Release of any pollut-
ant 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 is ma'de 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 hazard-
ous changes in local water chemistry.
Algicide: Substance or chemical used
specifically to kill or control algae.
Aliquot: A measured portion of a sample •
taken for analysis. One or more aliquots
make up a sample. (See: duplicate.)
Alkaline: The condition of water or soil
which contains a sufficient amount of
alkali substance to raise the pH above 7.0.
Alkalinity: The capacity of bases to
neutralize acids. An example is lime
added to lakes to decrease acidity.
Allergen: A substance that causes an
allergic reaction in individuals sensitive
to it.
Alluvial: Relating to and/or sand depos-
ited by flowing water.
. Alternate Method: Any method of
sampling and analyzing for an air or
water pollutant that is not a reference or
equivalent method but that has been
demonstrated in specific cases-to EPA's
satisfaction-to produce results adequate
for compliance monitoring.
Alternative Compliance: A policy that
allows facilities to choose among methods
for achieving emission-reduction or risk-
reduction instead of command-and con-
trol regulations that specify standards and
how to meet them. Use of a theoretical
emissions bubble over a facility to cap the
amount of pollution emitted while allow-
ing the company to choose where and
how (within the facility) it complies.(See:
bubble, emissions trading.)
Alternative Fuels: Substitutes for tradi-
tional liquid, oil-derived motor vehicle
fuels like gasoline and diesel. Includes
mixtures of alcohol-based fuels with
gasoline, methanol, ethanpl, compressed
natural gas, and others.
Alternative Remedial Contract Strategy
Contractors: Government contractors who
provide project management and techni-
cal services to support remedial response
activities at National Priorities List sites.
Ambient Air: Any unconfined portion of
the atmosphere: open air, surrounding
air.'
Ambient Air Quality Standards: (See:
Criteria Pollutants and National Ambient
Air Quality Standards.)
Ambient Measurement: A measurement
of the concentration of a substance or
pollutant within the immediate environs
of an organism; taken to relate it to the
amount of possible exp'osure.
Ambient Medium: Material surrounding
or contacting an organism (e.g., outdoor
air, indoor air, water, or soil, through
which chemicals or pollutants can reach
the organism. (See: biological medium^
environmental medium.)
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 current
that flows during a chemical reaction. '
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 oxygen-
free environment.
Animal -Dander: Tiny scales of animal
skin, a common indoor air pollutant.
Animal Studies: Investigations . using
animals as surrogates for humans with the
expectation that the results are pertinent
to humans.
Anisotropy: In hydrology, the conditions
under which one or more hydraulic
properties of an aquifer vary, from a
reference point.
Annular Space, Annulus: The space
between two concentric tubes or casings,
or between the casing and the borehole
wall. . ' -
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 the upper
atmosphere above a large area' of
Antarctica. (See: Ozone Hole.)
Anti-Degradation Clause: Part of federal
air quality and water quality require-
ments prohibiting deterioration where
pollution levels are above the legal limit.
Anti-Microbial: An agent that kills
microbes.
Applicable or Relevant and Appropriate
Requirements (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,
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Applied Dose: In exposure assessment,
the amount of a substance in contact with
the primary absorption boundaries of an
organism (e.g., skin, lung tissue, gas-
trointestinal track) and available for
absorption.
Aqueous Solubility: The maximum con-
centration of a chemical that will dissolve
in pure water aba reference temperature.
Aqueous Solubility: The maximum con-
centration of a chemical that will dissolve
in pure-Water at a reference temperature.
Aqueous: Something made up of water.
Aquifen An underground geological
formation, or group of formations, con-
taining water. Are sources of groundwa-
ter for wells and springs.
Aquifer Test A test to determine
hydraulic properties_of an aquifer.
Aquitard: Geological formation that may
contain groundwater but is not capable of
transmitting significant quantities of it
under normal hydraulic gradients. May
function as confining bed.
Architectural Coatings: Coverings such
as paint and roof tar that are used on
exteriors 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 injection operation.
Area Source: Any source of air pollution
that is released over a relatively small area
Tiut which cannot be classified as a point
source. Such sources may include vehicles
and other small engines, small businesses
and household activities, or biogenic
sources such as a forest that releases
hydrocarbons.
Aromatics: A type of hydrocarbon, such
as benzene or toluene, with a specific type
of ring structure. Aromatics are some-
times added to gasoline in order to
increase octane. Some aromatics are toxic.
Arsenicals: Pesticides containing arsenic.
Artesian (Aquifer or Well): Water held
under pressure in porous rock or soil
confined by impermeable geological for-
mations.
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 manu-
facturing and construction.
Asbestos Abatement: Procedures to con-
trol fiber release from asbestos-containing
materials in a building or to remove them
entirely, including removal, encapsulation,
repair, enclosure, encasement, and opera-
tions and maintenance programs.
Asbestos Assessment: In the asbestos-in-
schools program, the evaluation of the
4
physical condition and potential for
damage of all friable asbestos containing
materials and thermal insulation systems.
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.
Asbestos Program Manager: A building
owner or designated representative who
supervises all aspects of the facility
asbestos management and control pro-
gram. '
Asbestosis: A disease associated with
inhalation of asbestos fibers. The disease
makes breathing progressively more
difficult and can be fatal.
Ash: The mineral content of a product
remaining after complete combustion.
Assay: A test for a specific chemical,
microbe, or effect.
Assessment Endpoint: In ecological risk
assessment, an explicit expression of the
environmental value to be protected;
includes both an ecological entity and
specific attributed thereof, entity (e.g.,
salmon are a valued ecological entity;
reproduction and population mainte-
nance—the attribute—form an assessment
endpoint.)
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 deleteri-
ous 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 operators
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-attainment 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, an also be the-decrease
. with distance of sight caused by attenua-
tion of light by particulate pollution.
Attractant: A chemical or agent that lures
insects or other pests by stimulating their
sense of smell.
Attrition: Wearing or grinding down of a
substance by friction. Dust from such
processes contributes to air pollution.
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 chlorinat-
ed lime, hypochlorite compounds, and
other materials used as a source of
chlorine when compared with that of
liquid or gaseous chlorines.
Avoided Cost: The cost a utility would
incur to generate the next increment of
electric capacity using its own resources;
many landfill gas projects' buy back rates
are based on avoided costs.
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.
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: 1. The concentration
of a substance in an environmental media
(air, water, or soil) that occurs naturally or
is not the result of human activities. 2. In
exposure assessment the concentration of
a substance in a defined control area,
during a fixed period of 'time before,
during, or after a data-gathering
operation..
Backwashing: Reversing the flow of
water back through the filter media to
remove entrapped solids.
Backyard Composting: Diversion of
organic food waste and yard trimmings
from the municipal waste stream by
composting hem in one's yard through
controlled decomposition of organic mat-
ter by bacteria and fungi into a humus-like
product. It is considered source reduction,
not recycling, because the composted
materials never enter the municipal waste
stream.
Barrel Sampler: Open-ended steel tube
used to collect soil samples..
BACT-Best Available Control Technolo-
gy: An emission limitation based on the
maximum degree of emission reduction
(considering~energy, environmental, and
economic impacts) achievable through
application of production processes and
available methods, systems, and tech-
niques. 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
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emissions so-uices in attainment areas and
applies to each regulated pollutant. •
Bacteria: (Singular: bacterium) Micro-
scopic living organisms that can aid in
pollution control by metabolizing organic
'*• matter in sewage, oil spills or other
pollutants. However, bacteria in .soil,
wa1 ter or air can also cause human, animal
and plant health problems.
Baffle: A flat board or plate, deflector,
guide, or similar device constructed jor
placed in flowing water or slurry systems
to cause more uniform flow velocities to
absorb energy and to divert, guide, or
agitate liquids. . '
Baffle Chamber: In incinerator design, a
chamber designed to promote the settling
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.
Baghouse Filter: Large fabric bag, usually
made of glass fibers, used to eliminate
.intermediate and large (greater than 20
PM 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 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, or to collect ground-water samples
from wells or open boreholes. 2.A tube of
varying length
Baling: Compacting solid waste into
blocks to reduce volume and simplify
handling.
Ballistic Separator: A machine that sorts
organic from inorganic matter for compost-
ing.
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 transactions.
(See: emissiqns trading.)
Bar .Screen: In wastewater treatment, a
device used to remove large solids.
Barrier Coating(s): A layer of a material
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.
Basalt: Consistent year-round energy use
of a facility; also refers to the minimum
amount of electricity supplied continually
to a facility.
Bean Sheet: Common term for a pesticide
data package record.
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 analyz-
ing a violator's economic gain from not
complying with the law.
Bench-scale Tests: Laboratory testing of
potential cleanup technologies (See: treat-
ability studies.) ,
Benefit-Cost Analysis: An economic
method for assessing the benefits arid
costs of achieving alternative health-
based standards at given levels of health
protection.
Bentonite: A colloidal clay, expansible
when moist, commonly used to provide a
tight seal around a well casing.
Beryllium: An metal hazardous to human
health when inhaled as an airborne
pollutant. It is discharged by machine
shops, ceramic 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 dis-
persed particulates and other emissions
from sources such as roadway dust, soot
. and ash from woodstoves and open
burning of rush, timber, grasslands, or
trash. -
Best Available Control Technology
(BACT): For any specific source, the
currently available technology producing
the greatest reduction of air pollutant
emissions, taking - into account energy,
, environmental, economic, and other costs.
Best Available Control Technology
(BACT): The most stringent technology
available for controlling emissions; major
sources are required to use BACT, unless
it can' be demonstrated that it is not
feasible for energy, environmental, or
economic reasons.
Best Demonstrated Available Technol-
ogy (BOAT): 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): Meth-
ods that have been determined to be the
most effective, practical means of prevent-
ing or reducing pollution from non-point ,
sources. , :
Bimetal:- Beverage containers with steel
bodies and aluminum tops; handled
differently from pure' aluminum in
recycling. . ' ' '
Bioaccumulants: Substances that increase
in concentration in living organisms as
they take in contaminated air, water, or
food because the substances are very
slowly metabolized or excreted. (See:
biological magnification.) ,
Bioassay: A test to determine te relative
strength of a substance by. comparing its
. effect on a test organism with that of a ,
standard peparation.
Bioavailabiliity: Degree of ability to be
absorbed and ready to interact in
organism metabolism.
Biochemical Oxygen Demand (BOD): A
measure of the amount of oxygen
consumed 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
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 structures
that are the molecular basis of heredity.
Thus, the term encompasses different
ecosystems, species, and genes.
Biological Contaminants: Living organ-
isms or derivates(e.g., viruses, bacteria,
fungi, and mammal and bird antigens)
that can cause harmful health effects when
inhaled, swallowed, or otherwise taken
into the body. ,
Biological Control: In pest control, the
.- use of animals and organisms that eat or
otherwise kill or out-compete pests.
Biological Integrity: The ability to sup-
• port and maintain balanced, integrated,
functionality in the natural habitat of a
given region. Concept is applied prima-
rily in drinking water management.
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 internal organs as they move up the
chain. (See: bioaccumulants.)
Biological Measurement: A measure-
ment taken in a biological medium: For
exposure assessment, it is related to the
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measurement is taken to related it to the
established internal dose of a compound.
Biological Medium: One of the major
component of an organism; e.g., blood,
fatty tissue, lymph nodes or breath, in
which chemicals can be stored or
transformed. (See: ambient medium,
environmental medium.)
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 consumed in five days
by biological processes breaking down
organic waste.
Biological Stressors: Organisms acci-
dently or intentionally dropped into
habitats in which they do not evolve
naturally; e.g. gypsy moths, Dutch elm
disease, certain types of algae, and
bacteria.
Biological Treatment: A treatment
technology that uses bacteria to consume
organic waste.
Biologically Effective Dose: The amount
of a deposited or absorbed compound
reaching the cells or target sites where
adverse effect occur, or where the
chemical interacts with a membrane.
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.
Bkme Entire community of living
organisms in a single major ecological
area. (See: biotic community.)
Biomonitoring: 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 discharge. 2.
Analysis of blood, urine, tissues, etc., to
measure chemical exposure in humans.
Bioremediation: Use of living organisms
to clean up oil spills or remove other
pollutants from soil, water, or wastewa-
ter; use-of organisms such as non-harmful
insects to remove agricultural pests or
counteract diseases of trees, plants, and
garden soil.
Biosensor: Analytical device comprising
a biological recognition element (e.g.,
enzyme, receptor, DNA, antibody, or
microorganism) in intimate contact with
an electrochemical, optical, thermal, or
acoustic signal transducer that together
permit"analyses of chemical properties or
quantities. Shows potential development
in some areas, including environmental
monitoring.
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 liv-
ing organisms or parts of organisms to
produce a variety of products (from
medicines to industrial enzymes) to
improve plants or animals or to develop
microorganisms to remove toxics from
bodies of water, or act as pesticides.
Biotic Community: A naturally occurring
assemblage of plants and animals that live
in the same environment and are
mutually sustaining and interdependent.
(See: biome.)
Biotransformation: Conversion of a sub-
stance into other compounds by organ-
isms; includes biodegredation.
Blackwater: Water that contains animal,
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 licensed
products such'as interferon. i
Bloom: A proliferation of algae and/or
higher aquatic plants in a body of water;
often related to pollution, especially when
pollutants accelerate growth.
BODS: The amount of dissolved oxygen
consumed in five days by biological
processes breaking down organic matter.
Body Burden: The amount of a chemical
stored in the body at a given time,
especially a potential toxin in the body as
the result of exposure.
Bog: A type of wetland that accumulates-
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.
Boiler: A vessel designed to transfer heat
produced by combustion or electric
resistance to water. Boilers may provide
hot water or steam.
Boom: 1. A floating device used to contain
oil on a body of water. 2". A piece of
equipment used to apply pesticides from a
tractor or truck.
Borehole: Hole made with drilling
equipment.
Botanical Pesticide: A pesticide whose
active ingredient is a plant-produced
chemical such as nicotine or strychnine.
Also called a plant-derived pesticide.
Bottle Bill: . Proposed or enacted leg-
islation which requires a returnable
deposit on beer or soda containers and ^
provides for retail store or other redemp-
tion. Such legislation is designed to
discourage use of throwaway containers.
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 non-
combustible materials, which may include
toxics.
Bottom Land Hardwoods: Forested fresh-
water wetlands adjacent to rivers in the
southeastern United States, especially
valuable for wildlife breeding, nesting
and habitat.
Bounding Estimate: An estimate of
exposure, dose, or risk that is higher than
that incurred by the person in the
population with the currently highest
exposure, dose, or risk. Bounding esti-
mates are useful in developing statements
that exposures, doses, or risks are "not
greater than" an estimated value.
Brackish: Mixed fresh and salt water.
Breakpoint Chlorination: Addition of
chrlorine 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.
Breathing Zone: Area of air in which an
organism inhales.
Brine Mud: Waste material, often asso-
ciated, with well-drilling or mining,
composed of mineral salts or other
inorganic compounds.
British Thermal Unit: Unit of heat energy
equal to the amount of heat required to
raise the temperature of one pound of
water by one degree Fahrenheit at sea
level.
Broadcast Application: The spreading of
pesticides over an entire area.
Brownf ields: Abandoned, idled, or under
used industrial and commercial facilities/
sites where expansion or redevelopment
is complicated by real or perceived
environmental contamination. They can
be in urban, suburban, or rural areas.
EPA's Brownfields initiative helps com-
munities mitigate potential health risks
and restore the economic viability of such
areas or properties.
Bubble: A system under which existing
emissions sources can propose alternate
means to comply with a set of emissions
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limitations; under trie bubble concept,
sources can control more than required at
one emission point where control costs are
relatively low in return for a comparable
relaxation of controls at a second emission
point where costs are higher.-
Bubble Policy: (See: emissions trading.)
Buffer: A solution or liquid whose
chemical makeup is such that it minimizes
changes in -pH when acids or bases are
added to it.
Buffer Strips: Strips of grass or' other
erosionrresisting 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).
Building Envelope: The exterior surface
of a building's construction—the walls,
windows, floors, roof, and floor.
Also called building shell.
Building Related Illness: Diagnosable
illness whose cause and symptoms can be
directly attributed to'a specific pollutant
source within a building (e.g.,
Legionnaire's disease, hypersensitivity,
pneumonitis.) (See: sick building syn-
drome.)
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, furniture,
large auto parts, trees, stumps.
Burial Ground (Graveyard): A disposal
site for radioactive waste materials that
uses .earth or water as a shield.
Buy-Back Center: Facility where indi-
viduals or groups bring reyclables in
return for payment. '
By-product Material, other than the
principal product, generated as a conse-
quence of an industrial process or as a
•breakdown product in a living system. .
Cadmium (Cd): A heavy metal that
accumulates in the environment.
Cancellation: Refers to Section 6 (b) of the
Federal Insecticide, Fungicide and Roden-
ticide Act (FIFRA) which authorizes
cancellation of a pesticide'registration if
unreasonable adverse effects to the
environment and public health develop
when a product is used according to
widespread and commonly recognized
practice, or if its labeling or other material
required to be submitted does not comply
with FIFRA provisions.
Cap: A layer of clay, or other impermeable
material installed over the top of a closed
landfill to prevent entry of rainwater and
minimize leachate.
Capacity Assurance , Plan: A statewide
plan which supports a state's ability to
• manage the hazardous waste generated
, within its boundaries over a twenty year
period.'
Capillary Action: Movement of water
through very small spaces due . to
molecular forces called capillary forces.
Capillary Fringe: The zone above he
water table within which the porous
medium is .saturated by water under less
than atmospheric pressure. • ."
Capture Efficiency: The fraction of
organic vapors generated by a process
that are directed to an abatement or
recovery 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 system
that removes contaminants from ground
water or surface ^water by forcing it
through tanks containing activated car-
bon treated to attract the contaminants.
Carbon Monoxide (CO): A colorless,
odorless; poisonous gas produced by
incomplete fossil fuel combustion.
Carbon Tetrachloride (CC14): Com-
pound consisting of one carbon atom ad
four chlorine atoms, once widely used as a
industrial raw material, as a solvent, and
in the production of CFCs. Use as a solvent
ended when it was discovered to be
carcinogenic.
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: l.The inert liquid or solid
material in a pesticide product that serves
as a delivery vehicle for the active
ingredient. Carriers - do not have toxic
properties of their own. 2. Any material or
system that can facilitrate the'movement
of a pollutant into the body or cells.
Carrying Capacity: 1. In recreation
management, the amount of use a
recreation area can sustain without loss of '
"quality. 2. In wildlife management, the
maximum number of animals an area can
support during a, given period.
CAS Registration Number: A number
asigned by the Chemical Abstract Service
to identify a chemical.
Case Study: A brief fact sheet providing.
risk, cost, and, performance information
•on alternative methods and other pollu-
tion prevention ideas, compliance initia-
tives, voluntary efforts, etc.
Cask: A thick-walled container (usually
lead) used to transport radioactive materi-
al. 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 pollutants
from motor vehicle exhaust, either by
oxidizing them into carbon dioxide, and
water or reducing them to nitrogen.
Catalytic Incinerator: A control device
that oxidizes volatile organic compounds
(VOCs) by using a catalyst to promote the
combustion process. Catalytic incinera-
tors 'require lower temperatures than
conventional thermal incinerators, thus
saving fuel and other costs.
, Categorical Exclusion: A class of actions
which either individually or cumulatively
would not have a significant effect on the
human environment and therefore would
not require preparation of an .environ-
mental 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 Technol-
ogy (BAT) for direct dischargers.
Cathodic Protection: A technique to
prevent corrosion of a metal surface by
making it the cathode of an elec-
trochemical 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 pocket's 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 functioning as an
independent unit.
Cementitipus: Densely packed and non-
fibrous friable materials.
Central Collection Point: Location were a
generator of regulated medical waste
consolidates wastes originally generated
at various locations in his facility. The
wastes are gathered together for treat-
ment on-site or for transportation else-
where for treatment and/or disposal. This
term could also apply to community
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hazardous waste collections, industrial
and other waste management systems.
Centrifugal Collector: A mechanical
system using centrifugal force to remove
aerosols from a gas stream or to remove
water from 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 habitats, and
aggravate flooding.
Characteristic: Any one of the four
categories used in defining hazardous
waste: ignitability, corrosivity, reactivity,
and toxicity.
Characterization of Ecological Effects:
Part of ecological risk assessment that
evaluates ability of a stressor to cause
adverse effects under given circum-
stances.
Characterization of Exposure: Portion of
an ecological risk assessment that evalu-
ates interaction of a stressor with one or
more ecological entities.
Check-Valve Tubing Pump: Water sam-
pling tool also referred to as a water
Pump.
Chemical Case: For purposes of review
and regulation, the grouping of chemi-
cally similar pesticide active ingredients
(e.g., salts and esters of the same chemical)
into chemical cases,
Chemical Compound: A distinct and
pure substance formed by the union or
two or more elements in definite propor-
tion by weight.
Chemical Element: A fundamental sub-
stance comprising one kind of atom; the
simplest form of matter.
Chemical Oxygen Demand (COD): A
measure of the oxygen required to oxidize
all compounds, both organic and inor-
ganic, in water.
Chemical Stressors: Chemicals released
to the environment through industrial
waste, auto emissions, pesticides, and
other human activity that can cause
illnesses and even death in plants and
animals,
Chemical Treatment: Any one of a variety
of technologies that use chemicals or a
variety of chemical processes to treat
waste.
Chemnet: Mutual aid network of chemi-
cal shippere^md contractors that assigns a
contracted emergency response company
to provide technical support if a represen-
tative of the firm whose chemicals are
involved in an incident is not readily,
available.
Chemosterilant: A chemical that controls^
pests by preventing reproduction.
8
Chemtrec: the industry-sponsored Chem-
ical Transportation Emergency Center;
provides information and/or emergency
assistance to emergency responders.
Child Resistant Packaging (CRP): Pack-
aging that protects children or adults from
injury or illness resulting from accidental
contact with or ingestion of residential
pesticides that meet 6r exceed specific
toxicity levels. Required by FIFRA regula-
tions. Term is also used for protective •
packaging of medicines,
Chiller: A device' that generates a cold
liquid that is circulated through an air-
handling unit's cooling coil to cool the air
supplied to the building.
Chilling Effect: The lowering of the
Earth's temperature because of increased
particles in the air blocking the sun's rays.
(See: greenhouse effect.)
Chisel Plowing: Preparing croplands by
using a special implement that avoids
complete inversion of the soil as in
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: 1. Chemicals
containing only chlorine, carbon, and
hydrogen'. These include a class of
persistent, broad-spectrum insecticides
that linger in the environment and
accumulate in the food chain. Among
them are DDT, aldrm, dieldrin, hep-
tachlor, chlordane, lindane, endrin, Mirex,
hexachloride, and toxaphene. Other ex-
amples include TCE, used as an industrial
solvent. 2. Any chlorinated organic
compounds including chlorinated sol- •
vents such as dichloromethane,
trichlorornethylene, chloroform.
Chlorinated Solvent: An organic solvent
containing chlorine atoms(e.g., methylene
chloride and 1,1,1-trichloromethane). Uses
of chlorinated solvents are include aerosol
spray containers, in highway paint, and
dry cleaning fluids.
Chlorination: The application of chlorine
to drinking water, sewage, or industrial
waste to disinfect or to oxidize undesir-
able compounds.
Chlorinator: A device that adds chlorine,
in gas or liquid form, to water or sewage to
kill infectious bacteria.
Chlorine-Contact Chamber: That part of
a water treatment plant where effluent is
disinfected by chlorine.
Chlorofluorocarbons (CFCs): A family of
inert, nontoxic, and easily liquefied
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 com-
ponents destroy ozone. (See: fluorocar-
bons.)
Chlorophenoxy: A class of herbicides that
may be found in domestic water supplies
and cause adverse health effects.
Chlorosis: Discoloration of normally
green plant parts caused by disease, lack
of nutrients, or various air pollutants.
Cholinesterase: An enzyme found in
animals that regulates nerve impulses by
the inhibition of acetylcholine.. Cholin-
esterase 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.
Chronic Exposure: Multiple exposures
occurring over an extended period of time
or .over a significant fraction of an
animal's or human's lifetime (Usually
seven years to a lifetime.)
Chronic Toxicity: The capacity of a
substance to cause long-term poisonous
health effects in humans, animals, fish,
and other organisms.. (See: acute toxicity.)
Circle of Influence: The circular outer-
edge of a depression 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 chemically induced
coagulation in wastewater.
Clarifiejr: A tank in which solids settle to
the bottom and are subsequently removed
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 stan-
dards; includes national parks, wilder-
ness areas, monuments, and other areas of
special national and cultural significance.
Class I Substance: One of several groups
of chemicals with an ozone depletion
potential of 0.2 or higher, including CFCS,
Halons, Carbon Tetrachloride, and Me-
thyl Chloroform (listed in the Clean Air
Act), and HBFCs and Ethyl Bromide
(added by EPA regulations). (See: Global
warming potential.)
Class II Substance: A substance with an
ozone depletion potential of less than 0.2.
All HCFCs are currently included in this
-------
classification.. (Seei Global warming po-
tential.)
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- reductions in
pollutants associated with the burning of
coal.
Cleaner Technologies Substitutes! As-
sessment: A document that systematically
evaluates the relative risk, performance,
and . cost trade-offs of technological
alternatives; serves as a repository for all
the technical data (including methodol-
ogy and results) developed by a DfE or
other pollution prevention or education
project.
Clean Fuels; Blends or substitutes for
gasoline fuels, including compressed
natural gas, methanol, ethanol, and
liquified petroleum gas.
Cleanup: Actions taken to deal with a
release or threat of release of a hazardous
substance that could affect humans and/
or the environment. The term "cleanup" is
sometimes used interchangeably 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, sedimentation of streams
and lakes, and 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
variations in demand. Also used to
provide chlorine contact time for disinfec-
tion. . .
Cloning: In biotechnology, obtaining -a
group of genetically identical cells from a
single cell; making identical copies of a
gene.
Closed-Loop Recycling: Reclaiming or
reusing wastewater for non-potable pur-
poses in an enclosed process.
Closure: The procedure a landfill opera-
tor must follow when a landfill reaches its
legal capacity for solid waste: ceasing
acceptance of solid waste and placing a
cap on the landfill site.
Co-fire: Burning of two fuels in the same
combustion unit; e.g., coal and natural
gas, or oil and coal. '
Coagulation: Clumping of particles in
wastewater to settle out impurities, often
induced by chemicals such as lime, alum,
and iron salts. ,
Coal Cleaning Technology: A precom-
bustion process by. which coal is physi-
cally 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.
1 Coastal Zone: Lands and waters adjacent
to the coast that exert an influence on the
uses of the sea and its ecology, or whose
uses and ecology are affected by the sea.
Code of Federal Regulations (CFR):
Document that codifies all rules of the
executive departments and agencies of the
federal government. It is divided into fifty
volumes, known as titles. Title 40 of the
CFR (referenced as 40 CFR) lists. all
environmental regulations.
Coefficient of Haze (COH); A measure-
ment of visibility interference in the
atmosphere.'
Cogeneration: The ^consecutive genera-
• tion of useful thermal and electric energy
from the same fuel source.
Coke Oven: An industrial process which
converts coal into coke, one of the basic
materials used in blast furnaces for the
conversion of iron ore into iron.
Cold Temperature CO: A standard for
automobile emissions of carbon monoxide
(CO) emissions to be met at a low
temperature (i.e. 20 degrees Fahrenheit).
Conventional automobile catalytic conver-
ters are not efficient in cold weather until
they warm up.
Coliform Index: A rating of the purity of
water based on a count of fecal bacteria.
Coliform Organism:. Microorganisms
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.
Collector: Public or private hauler-that
collects nonhazardous waste and recy-
clable materials from residential/commer-
cial, institutional and industrial sources.
(See: hauler!)
Colloids: Very small, finely divided
• solids (that do not dissolve) that remain
dispersed in a liquid for a long time due to
their small size and electrical charge.
Combined Sewer Overflow;s: Discharge
of a mixture of storm water and domestic
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
grea.t as to cause overflows of untreated
mixtures of storm water and sewage into
receiving waters. Stornvwater runoff may
also carry toxic chemicals from industrial
areas or streets into the sewer system.
Combustion: 1. Burning, or rapid oxida-
tion, accompanied by release of energy in
the form of heat and light. ;2. Refers to
controlled burning of waste, in which heat
chemically alte'rs organic compounds,
converting 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 Post: Facility located at a safe
distance upwind from an accident site,
where the on-scehe coordinator, respond-
ers,.and technical representatives make
response decisions, deploy manpower
and equipment, maintain liaison wjth
news media, and handle communications.
Command-and-Control Regulations: Spe-
cific requirements prescribing how to
comply with specific standards defining'
acceptable levels of pollution.
'Comment Period: Time provided for the
public to, review and comment on a
proposed EPA action or rulemaking after
publication in the Federal Register.
Commercial Waste: All solid waste
emanating from business establishments
such as stores, markets, office buildings,
restaurants, shopping centers, and the-
aters.
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 generated by its own
operations.
Commingled Recyclables: Mixed recyc-
lables that are collected together.
Comminuter: A machine that shreds or
pulverizes'solids to make waste treatment
easier. .
Comminution: Mechanical shredding or
pulverizing of waste. Used in both solid
waste management and wastewater treat-
ment. ' •
Common Sense Initiative: Voluntary
program to simplify environmental regu-
lation to achieve cleaner, cheaper, smarter
results, starting with six major industry
sectors.
Community: In ecology, an assemblage
of populations of different specieis within
a specified location in space and time.
Sometimes, a particular subgrouping may
be specified, such as the fish community in
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a lake or the soil arthropod community in
a forest.
Community Relations: The EPA effort to
establish two-way communication with
the public to create understanding of EPA
programs and related actions, to ensure
public input into decision-making pro-
cesses 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.
Compact Fluorescent Lamp (CFL): Small
fluorescent lamps used as more efficient
alternatives to incandescent lighting. Also
called PL, CFL, Twin-Tube, or BIAX
lamps.
Compaction: Reduction of the bulk of
solid waste by rolling and tamping.
Comparative Risk Assessment: Process
that generally uses the judgement of
experts to predict effects and set priorities
among a wide range of environmental
problems.
Complete Treatment: A method of
treating water that consists of the addition
of coagulant chemicals, flash mixing,
coagulation-flocculation, sedimentation,
and filtration. Also called conventional
filtration.
Compliance Coal: Any coal tht emits less
than 1.2 pounds of sulfur dioxide per
milion 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-monitor-
ing reports, and verification to show
whether pollutant concentrations and
loads contained in permitted discharges
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.
Composite Sample: A series of water
samples taken over a given period of time
and weighted by flow rate.
Compost The relatively stable humus
material that is produced from a compost-
ing process in which bacteria in soil mixed
with garbage and degradable trash break
down the mixture into organic fertilizer.'
Composting Facilities: 1. An offsite
facility where the organic component of
municipal solid waste is decomposed
under controlled conditions; 2.an aerobic
process in which organic materials are
ground or shredded and then decom-
posed to humus in windrow piles or in
mechanical digesters, drums, or similar
enclosures.
Composting: The controlled biological
decomposition of organic material in the
presence of air to form a humus-like
material. Controlled methods of compo-
sting 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 Gas (CNG): An
alternative fuel for motor vehicles; consid-
ered one of the cleanest because of low
hydrocarbon emissions and its vapors are
relatively non-ozone producing. How-
ever, vehiles fueled wih CNG do emit a
significant quanity of nitrogen oxides.
Concentration: The relative amount of a
substance mixed with another substance.
An example is five ppm of carbon
monoxide in air or 1 mg/1 of iron in water.
Condensate:!.Liquid formed when warm
landfill gas cools as it travels through a
collection system- 2. Water created by
cooling steam or water vapor.
Condensate Return System: System that
returns the heated water condensing
within steam piping to the boiler and thus
saves e"nergy.
Conditional Registration: Under special
circumstances, the Federal Insecticide,
Fungicide, and Rodenticide Act (FIFRA)
permits registration of pesticide products
that is "conditional" upon the submission
of additional data. These special circum-
stances 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
effects. A product containing a new
(previously unregistered) active ingre-
dient 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 pesticide for
the period of conditional registration will
not present an unreasonable risk.
Conditionally Exempt Generators (CE):
Persons or enterprises which produce less
than 220 pjaunds of hazardous waste per
•month. Exempt from most regulation,
they are required merely to determine
whether their waste is hazardous, notify
appropriate state or local agencies, and
ship it by an authorized transporter to a
permitted facility for proper disposal.
(See : small quantity generator.)
Conductance: A rapid method of estimat-
ing the dissolved solids content of water
supply by determining the capacity of a
water sample to carry an electrical
current. Conductivity is a measure of the.
ability of a solution to carry and electrical
curerent.
Conductivity: A measure of the ability of
a solution to carry an electrical current.
Cone of Depression: A depression iri the
water table that develops around a
pumped well.
Cone of Influence: The depression,
roughly conical in shape, produced in a
water table by the pumping of water from
a well.
Cone Penterometer Testing (CPT): A
direct push system used to measure
lithology based on soil penetration
resistance. Sensors in the tip of the cone of
the DP rod measure tip resistance and
side-wall friction, transmitting electrical
signals to digital processing equipment on
the ground surface. (See: direct push.)
Confidential Business Information (CBI):
Material that contains trade secrets or
commercial or financial information that
has been claimed as confidential by its
source (e.g., a pesticide or new chemical
formulation registrant). EPA has special
procedures for handling such informa-
tion.
Confidential Statement of Formula (CSF):
A list of the ingredients in a new pesticide
or chemical formulation. The list is
submitted at the time for application for
registration or change in formulation.
Confined Aquifer: An aquifer in which
ground water is confined under pressure
which is significantly greater than atmo- -
spheric 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,,
approved 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 processes
that are polluting the environment; or
otherwise comply with EPA initiated
regulatory enforcement actions to resolve
the contamination at the Superfund site
involved. The consent decree describes
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-a^t\.c«xs T3RPS -will take'and may be
subject to a public comment period.
Conservation: Preserving and renewing,
when possible, human and natural
resources. „ The use, protection,' and
improvement of natural resources ac-
cording to principles that will ensure their
highest economic or social benefits.
Conservation Easement: Easement re-
stricting a landowner to land uses that
that are compatible with long-term
conservation and environmental values.
Constituent(s) of C6ncern:Specific chemi-
cals that are identified for evaluation in
the site assessment process
Construction and Demolition Waste:
Waste building materials, dredging materi-
als, tree stumps, and rubble resulting from
construction, remodeling, repair, and
demolition of homes, commercial build-
ings and other structures and pavements.
May contain lead, asbestos, or other
hazardous substances.
Construction Ban: If, under the Clean Air
Act, EPA disapproves an area's planning
requirements for , correcting
nonattainment, EPA can ban the construc-
tion or nmodification of any major
stationary source of the pollutant for
which the area is in nonattainment.
Consumptive Water Use: Water removed
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-coated in-
sects. • • "
Contaminant Any physical, chemical,
biological, or radiological substance or
matter that has an adverse effect on air,
water, or soil.
Contamination: Introduction into water,
air, and soil of microorganisms, chemi-
cals, toxic substances, wastes, or wastewa-
ter 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 products.
Contamination Source Inventory: An
inventory of contaminant sources within
delineated State Water-Protection Areas.,
Targets likely sources for further investi-
gation. - '
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 accident
that releases toxic chemicals,, hazardous
waste, or radioactive materials that
threaten human health or the environ-
ment. (See: National Oil and Hazardous
Substances'Contingency Plan.)
Continuous Discharge: A routine release
to the environment .that occurs without
interruption, except for infrequent shut-
.dpwns for maintenance, process changes,
etc. • '.•':." ' - -. : •
Continuous Sample: A flow of water,
waste or other material from a-particular
place in a plant to the location where
samples are collected for testing. May be '
used to obtain grab or composite samples.
Contour Plowing: Soil tilling method, that
follows the shape 'of. the .land to
discourage erosion.
Contour Strip Farmiong: A' kind of
contour farming in which row crops are
planted in strips, between alternating
stripls of close-growing, erosion-resistant
forage crops. •
Contract Labs: Laboratories under con-
tract to EPA, which analyze samples taken
from waste, soil, air, and water tir carry
'out research projects.
Control Technique Guidelines (CTG):
EPA documents designed to assist state
and local pollution authorities to achieve
and maintain air quality standareds for
certain sources (e.g. -organic emissions
from solvent metal cleaning known as
degreasing) through reasonably available
control technologies (RACT).
Controlled Reaction: A chemical reaction
under temperature and pressure condi-
tions maintained withiri safe limits to
produce a desired product or process.
Conventional Filtration: (See: complete
treatment) ' :
ConventionalPollutants:Statutorily listed
pollutants understood well by scientists.
These may be in the form of organic waste, .
sediment, acid, bacteria, viruses/nutri-r
ents, oil and grease, or heat.
Conventional Site Assessment: Assess-
ment in which most of the sample analysis
and interpretation of data is completed
"off-site; process usually requires repeated
mobilization of equipment and staff in
order to fully determine the extent of
contamination. r •
Conventional Systems: Systems that
have been traditionally used to collect
municipal wastewater in; gravity sewers
and convey it to a central primary or
secondary treatment plant prior to dis-
charge to surface waters. ,. •
Conventional Tilling: Tillage operations
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.)
tooling Tower; Device which dissipates
the heat from water-cooled systems by
spraying the water through streams of
rapidly moving air.
Cooperative Agreement An. assistance
agreement whereby EPA transfers money,
property, services or anything of value to
a state, university, non-profit, or not-for-
profit organization for the accomplish-
ment of authorized activities or tasks.
Core: The uranium-containing heart of a
nuclear reactor, where energy is released.
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.
Corrective Action: EPA can require
treatment, storage and. disposal (TSDF)
facilities handling hazardous waste to
undertake corrective actions to clean up
spills resulting from failure to follow
hazardous waste management proce-
dures or other mistakes. The process
includes cleanup procedures designed to
guide TSDFs toward in spills.
Corrosion: The dissolution and wearing
away of metal caused by a chemical
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.
Cost/Benefit Analysis: A quantitative
' evaluation of the costs which would bve
incurred by implementing an
environbmental regulation versus the
overall benefits to society of the proposed
.action.
Cost Recovery: A legal process by which
potentially responsible parties who
contributed to contamination at a
Superfund site can be required to
( reimburse 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
beneficiary 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.
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Cost-Effective Alternative: An alterna-
tive control or corrective method identi-
fied after analysis as being the best
available in terms of reliability, perfor-
mance, and cost. Although costs are one
important consideration, regulatory and
compliance analysis does not require EPA
to choose the least expensive alternative.
For example, when selecting or pproving
a method for cleaning up a Superf und site,
the Agency balances costs with the long-
term effectiveness of the methods pro-
posed and the potenetial danger posed by
the site.
Cover Crop: A crop that provides
temporary protection for delicate seed-
lings and/or provides a cover canopy for
seasonal soil protection and irmprovement
between normal crop production periods.
Cover Material: Soil used to cover
compacted solid waste in a sanitary
landfill.
Cradle-to-Grave or Manifest System: A
procedure in which hazardous materials
are identified and followed as they are
produced, treated, transported, and dis-
posed of by a series of permanent,
linkable, descriptive documents (e.g.,
manifests). Commonly referred to as the
cradle-to-grave system.
Criteria: Descriptive factors taken into
account by EPA in setting standards for
various pollutants. These factors are used
to determine limits on allowable concentra-
tion levels, and to limit the number of
violations per year. When issued by EPA,
the criteria provide guidance to the states
on how to establish their standards.
Criteria Pollutants: The 1970 amend-
ments to the Clean Air Act required EPA
to set National Ambient Air Quality
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, carbon monoxide, total
suspended particulates, 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.
Critical Effect: The first adverse effect, or
its known precursor, that occurs as a dose
rate increases. Designation is based on
evaluation of overall database.
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
system and an unapproved water supply
or other source of contamination.
Cross Contamination: The movement of
underground contaminants from one
level or area to another due to invasive
subsurface activities.
Crumb Rubber: Ground rubber frag-
ments the size of sand or silt used in
rubber or plastic products, or processed
further into reclaimed rubber or asphalt
products.
Cryptosporidium: A protozoan microbe
associated with the disease
cryptosporidiosis in man. The disease can
be transmitted through ingestion of
drinking water, person-to-person contact,
or other pathways, and can cause acute
diarrhea, abdominal pain, vomiting,
fever, and can be fatal as it was in the
Milwaukee episode.
Cubic Feet Per Minute (CFM): A measure
of the volume of a substance .flowing
through air within a fixed period of time.
With regard to indoor air, refers to the
amount of air, in cubic feet, that is
exch'anged with outdoor air in a minute's
time; i.e., the'air exchange rate.
Cullet: Crushed glass.
Cultural Eutrophication: Increasing rate
at which water bodies "die" by pollution
from human 'activities. Cultures and
Stocks: Infectious agents and associated
biologicals including: cultures from medi-
cal 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, inoculate, and mix cultures. (See:
regulated medical waste.)
Cultures and Stocks: Infectious agents
and associated biologicals including cul-
tures 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,
inoculate, and mix cultures. (See: regu-
lated medical waste.)
Cumulative Ecological Risk Assessment:
Consideration of the total ecological risk
from multiple stressors to a given eco-
zone.
Cumulative Exposure: The sum of
exposures of an organism to a pollutant
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.
Curbside Collection: Method of col-
lecting recyclable materials at homes,
community districts or businesses.
Cutie-Pie: An instrument used to measure
radiation levels.
Cuttings: Spoils left by conventional
drilling with hollow stem auger or rotary
drilling equipment.
Cyclone Collector. A device that uses
centrifugal force to remove large particles
from polluted air.
D
Data Call-In: A part of the Office of
Pesticide Programs (OPP) process of
developing key required test data, espe-
cially on the long-term, chronic effects of
existing pesticides, in advance of sched-
uled Registration Standard reviews. Data
Call-In from manufacturers is an adjunct
of the Registration Standards program
intended to expedite re-registration.
Data Quality Objectives (DQOs): Quali-s
tative and quantitative statements of the
overall level of uncertainty that a
decision-maker will accept in results or
decisions based on environmental data.
They provide the statistical framework for
planning and managing environmental
data operations consistent with user's
needs.
Day Tank: Anotrher name fr deaerating
tank. (See: age tank)
DDT: The first chlorinated hydrocarbon
insecticide chemical name: Dichloro-
Diphenyl-Trichloroethane). It has a half-
life of 15 years and can. collect in fatty
tissues of certain animals. EPA banned
registration and interstate 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.
Deadmen: Anchors drilled or cemented
into the ground to provide additional
"reactive" mass for DP sampling rigs.
Decant: To draw off the upper layer of
liquid after the heaviest material (a solid
or another liquid) has settled.
Decay Products: Degraded radioactive
materials, often referred to as "daughters"
or "progeny"; radon decay products of
most concern from a public health
standpoint are polonium-214 and poloni-
" um-218.
Dechlorination: Removal of chlorine
from a substance.
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Decomposition: The breakdown of
matter toy bacteria and fungi, changing the
chemical makeup and physical ap-
pearance of materials.
Decontamination: Removal of harmful
substances such as noxious chemicals,
harmful bacteria or other organisms, or
radioactive material from exposed individ-
uals, 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.
Defluoridation: The rmeoval of excess
flouride in drinking water to prevent the
staining of teeth.
Defoliant An herbicide that removes
leaves from'trees and growing plants.
> Degasification: A water treatment that
removes dissolved gases from the water.
Degree-Day: A rough measure used to
estimate the amount of heating required
in a given area; is defined as the difference
between the mean daily temperature and
65 degrees Fahrenheit. Degree-days are
also calculated tb estimate cooling re-
quirements.
Delegated State: A state (or other
governmental entity such as a tribal
government) that has received authority'
to administer an environmental regula-
tory program in lieu of a federal,
counterpart. As used in connection with
NPDES, UIC, and PWS programs, 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 rescinded.
Demand-side Waste Management: Prices
whereby consumers use purchasing deci-
sions to communicate to product manu-
facturers that they prefer environmentally
sound products packaged with the least
amount of waste, made from recycled or
recyclable materials, and containing no
hazardous substances.
Demineralization: A treatment process
that removes dissolved minerals from
water. •...''
Denitrif ication: The biological reduction
of nitrate to nitrogen gas by 'denitrifying
bacteria in soil.
Dense Non-Aqueous Phase Liquid
(DNAPL): Non-aqueous phase - liquids
such as chlorinated hydrocarbon solvents
or petroleum fractions with ,a specific
gravity greater than 1.0 that sink through
the water column, until they reach a
confining layer. Because they.are at the
bottom of aquifers instead t>f floating on
the water table, typical monitoring wells
do not indicate their presence.
Density: A measure of how heavy a"
specific volume of a solid, liquid, or gas is
in comparison to water.
Depletion Curve: In hydraulics, a graphi-
cal representation of water depletion from
storage-stream channels, surface soil, and
groundwater. A depletion curve can be
drawn for base flow, direct runoff, or total
flow.
Depressurization: A condition that oc-
curs when. the air pressure inside a
structure is lower that the air pressure
outdoors. 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 depres-
surized conditions.
Dermal Absorption/Penetration: Process
by which a chemical penetrates the skin
and enters the body as an internal dose.
Dermal Exposure: Contact between a
chemical and the skin.
Dermal Toxicity: The ability of a pesticide
of toxic chemical, to poison people or
animals by contact with the skin. (See:
. contact pesticide.)
DBS: A synthetic estrogen, diethylstilbes-
trol is used as a growth stimulant in food
animals. Residues in meat are thought to
• be carcinogenic.
Desalination: [Desalinization] (1) Remoy-
'ing salts from ocean or brackish water by
using various technologies. (2) Removal
of salts from soil by artificial means,
usually leaching.
Desiccant: A chemical agent that absorbs
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 hazardous
pollutant, as described in the Clean Air
Act, but for which new source perform- "
ance standards exist. The Clean Air Act
does require states to control these
pollutants, which include acid mist, total
reduced sulfur (TRS), and fluorides^
Designated Uses: Those water uses
identified in state water quality standards '
that must be achieved and maintained as
required under the Clean Water Act. Uses
-•can include cold water fisheries, public
water supply, and irrigation.
Designer Bugs: Popular term for mi-
crobes developed through biotechnology
that can degrade specific toxic chemicals
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.
Destratification: Vertical mixing within a
; lake or reservoir to totally or partially
eliminate separate layers of temperature,
plant, or animal life.
Destroyed Medical Waste: Regulated
medical waste that has been ruined, torn
apart, - or mutilated through thermal
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 compound
removed or destroyed in an incinerator
relative to the number of molecules.
entering 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
, requirement may be as stringent as "six
nines"). . • i '
Destruction Facility: A facility 'that
destroys regulated medical waste.
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 is leaking
or not; Most, volumetric tests use a
threshold value as the detection criterion.
(See: volumetric tank tests.)' -
Detection Limit: The lowest concentra-
tion of a chemical that can reliably be
distinguished from a zero concentration.
Detention Time: 1. The theoretical
calculated 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, flocculating basin, or rapid-mix
chamber. .3. In storage reservoirs, the
length of time water will be-held before
being used.
Detergent: Synthetic washing agent that
helps tb remove dirt and oil.'Some contain.
13
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compounds which kill useful bacteria and
encourage algae growth when they are in
wastewater that reaches receiving waters.
Development Effects: Adverse effects
such as altered growth, structural abnor-
mality, functional deficiency, or death
observed in a developing organism.
Dewaten 1. Remove or separate a portion
of the water in a sludge or slurry to dry the
sludge so it can be handled and disposed
of. 2.Remove or drain the water from a
tank or trench.
Diatomaceous 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 powdered 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 establishment uses.
Dibenzofurans: A group of organic
compounds, some of which are toxic.
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 (or molecules) from
a more concentrated to a less concentrated
area. The process tends to distribute the
particles or molecules more uniformly.
Digester: In wastewater treatment, a
closed tank; in solid-waste conversion, a
unit in which bacterial action is induced
and accelerated in order to break down
organic matter-and establish the proper
carbon to nitrogen ratio.
Digestion: The biochemical decomposi-
tion of organic matter, resulting in partial
gasification, liquefaction, and mineraliza-
tion of pollutants.
Dike: A low wall that can act as a barrier
to prevent a spill from spreading.
Diluent: Any liquid or solid material used
to dilute or carry an active ingredient.
Dilution Ratio: The relationship between
the volume of water in a stream and the
volume of incoming water. It affects the
ability of the stream to assimilate waste.
Dimictic: 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
diseases. EPA proposed restrictions on its
use in 1986 when laboratory tests found it
caused birth defects in rabbits.
14
Dinoseb: 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 as contaminants in
commercial products. Tests on laboratory
animals indicate that it is one of the more
toxic anthropogenic (man-made) com-
pounds.
Direct Discharger: A municipal or indus-
trial 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, coagu-
lation, minimal flocculation, and filtra-
tion. Sedimentation is not uses.
Direct Push: ^Technology used for per-
forming subsurface investigations by
driving, pushing, and/or vibrating small-
diameter hollow steel rods into the
ground/ Also known as direct drive,
drive point, or push technology.
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 artesian well, ditch,
or spring. Can also apply tp discharge of
liquid effluent from a facility or to
chemical emissions into the air through
designated venting mechanisms.
Disinfectant A chemical or physical
process that kills pathogenic organisms in
water, air, or on surfaces; Chlorine is often
used to disinfect sewage treatment
effluent, water supplies, wells, and
swimming pools.
Disinfectant By-Product: A compound
formed by the reaction of a disinfenctant
such as chlorine with organic material in
the water supply; a chemical byproduct of
the disinfection process.
Disinfectant Time: The time it takes
water to move from the point of
disinfectant 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. In pipelines, the time is calculated
by dividing the internal volume of the
pipe by he maximum hourly flow rate;
within mixing basins and storage resrvoirs
it is determined by tracer studies of an
equivalent demonstration.
Dispersant: A chemical agent used to
break up concentrations of organic
material such as spilled oil.
Displacement Savings: Saving realized
by displacing purchases of natural gas or
electricity .from a local utility by using
landfill gas for power and heat.
Disposables: Consumer products, other
items, and packaging used once or a few
times and discarded.
Disposal: Final placement or destruction
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 accomplished through
use of approved secure landfills, surface
impoundments, land farming, deep-well
injection, ocean dumping, or incineration.
Disposal Facilities: Repositories for solid
waste, including landfills and combustors
intended for permanent containment or
destruction of waste materials. Excludes
transfer stations and composting facili-
ties.
Dissolved Oxygen (DO): The oxygen
freely available in water, vital to fish and
other aquatic life and for the prevention of
odors. DO levels are considered a most
important indicator of a water body's
ability to support desirable aquatic life.
Secondary and advanced waste treatment
are generally designed to ensure adequate
DO in waste-receiving waters.
Dissolved Solids: Disintegrated organic
and inorganic material in water. Exces-
sive amounts make water unfit to drink or
use in industrial processes.
Distillation: The act of purifying liquids
through boiling, so that. the steam or
gaseous vapors condense to a pure liquid.
Pollutants and contaminnts may remain
in a concentrated residue.
Disturbance: Any event or series of events
that disrupt ecosystem, community, or
population structure and alters the
physical environment.
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 divert water
at a non-erosive velocity to sites where it
can be used and disposed of.
Diversion Rate: The percentage of waste
materials diverted from traditional dispos-
al 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 identify its
complementary DNA; used to detect
specific genes.
Dobson Unit (DU): Units of ozone level
measurement, measurement of ozone
levels. If, for example, 100 DU of ozone
were brought to the earth's surface they
would form a layer one millimeter thick.
Ozone levels vary geographically, even in
the absence of ozone depletion.
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. A^flic.a.tioYv. Pesticide applica-
tion in and around houses, office
buildings, motels, and other living .or
working areas.(See: residential use.)
Dosage/Dose: 1. The actual quantity of a
" chemical administered to an organism or
to which it is exposed. 2. The amount of a
substance that reaches a. specific tissue
(e.g., the liver). 3. The amount of a
substance available for interaction with
metaboic processes after crossing the
outer boundary of an organism. (See:
absorbed dose, administered dose, ap-r
plied dose, potential dose.) '.
Dose Equivalent The product of the
absorbed dose from ionizing radiation
and such factors as account for biological
differences due to the type of radiation
and its distribution in the body in the
body. ',''''"•
Dose Rate: In exposure assessment, dose
p'er time unit (e.g., ring/day), sometimes
also called dosage. "
Dose Response: Shifts in toxicologieal
.responses of an individual (such as
alterations in severity) or populations
(such as alterations in incidence) that are
related to changes in the dose of any given
substance.
Dose-Response Assessment: 1. Estimat-
ing the potency of a chemical. 2. In
exposure assessment, the process of
determining the relationship between the
dose of a stressor and a specific biological
response. 3,. Evaluating the quantitative
relationship between dose and toxicologir
cal responses.
Dose Response, Curve: Graphical repre-
sentation of. the relationship between the
dose of a stressor and the biological
response .thereto. - • •
Dose-Response Relationship: The quan-
titative relationship between the amount
of exposure to a substance and the extent
of toxic injury or disease produced.
Dosimeter: An instrument to measure
dosage; many so-called dosimeters actu-
ally measure exposure rathef than dosage.
Dosimetry is the process or technology of
measuring and/or estimating dosage.
DOT Reportable Quantity: The quantity
of a substance specified in a U.S.
Department of Transportation regulatipn
that • triggers labeling, packaging and
other requirements related to shipping
such substances. ' ' ' • .
Downgradient: The direction tht ground-
water flows; similar to "downstream" for
surface water.
Downstream Processors: Industries de-
pendent on crop production (e.g., canner-
ies and food processors).
DP Hole: Hole in the ground made with
DP equipment. (See: direct push.)
Draft: 1. The act of drawing or removing
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
i 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 groundwaterbelow. Drain-
age 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 of
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 disturb
the ecosystem and causes silting that kills
aquatic life. Dredging of contaminated
muds can expose biota to heavy metals
and other toxics. Dredging activities may
be subject to regulation under Section 404
of the Clean Water Act.
Drilling Fluid: Fluid used to lubricateihe
bit and convey drill cuttings to the surface
with rotary drilling equipment. Usually
composed of bentonite slurry or muddy
water. Can become contaminated, leading
to cross contamination, and may require
special disposal. Not used with DP
methods ...
Drinking Water Equivalent Level: Pro-
tective level of exposure related .to
potentially non-carcinogenc effects of
chemicals that are also known to cause
cancer. .
Drinking Water State Revolving Fund:
The Fund provides capitalization grants
to states to develop drinking water
revolving loan funds to help finance
system infrastructure improvements, as-
sure source-water protection, enhance
operation and management of drinking-
water systems, and otherwise promote
local water-system compliance and pro-
tection of public health.
Drive Casing: Heavy duty steel casing
driven along with the sampling tool in
cased DP systems. Keeps the hole open
between sampling runs arid is not
removed until last sample has been
collected.
Drive Point Profiler: An exposed ground-
wafer DP system used to collect multiple
depth-discrete groundwater samples. Ports
in the tip of the probe connect to an
internal stainless steel or teflon tube that
extends to the. surface. Samples are
collected via suction or airlift methods.
Deitinized water is pumped down through
the ports to" prevent plugging while
driving the tool to the next sampling
depth. ,
Drop-off: Recyclable materials collection
method in which individuals bring them
to a designated collection site. '
Dual-Phase Extraction: • Active' with-
drawal of both liquid and gas phases from
a well usually involving the- use of a
vacuum pump.
Dump: A site used to dispose of,solid
waste without environmental controls.
Duplicate: A second aliquot or sample
that is treated the same as the original
sample in order to determine the precision
of the analytical method. (See: aliquot.)
, Dustfall Jar: An open container used to
collect large particles from the air for
measurement and analysis.
Dystrpphic Lakes: Acidic, shallow bodies
of water that contain much humus and/or
other organic matter; contain many plants
but few fish. • , •
Ecological Entity: In ecological risk
assessment, a general term referring to a
species, a group of species, an ecosystem
function or characteristic, or a specific,
. habitat or biome, '
Ecological/Environmental Sustainability:
Maintenance of ecosystem components
and functions for future generations.
Ecological Exposure: Exposure of a non-
human organism to a stressor. ••
Ecological Impact: The effect that a irian-
' caused or natural activity has on living
organisms and their non-living (abiotic)
environment.
Ecological Indicator: A characteristic, of
an ecosystem that is related to, or derived
from, a measure of biotic or abiotic
variable, that can provide quantitative
information on ecological structure and
function. An indicator can contribute to a
measure of integrity and sustainability.
Ecological Integrity: A living system
exhibits integrity if, when subjected to
disturbance, it sustains and organizes
self-correcting ability to recover toward a
biomass end-state that is normal for that
system. End-states other than the pristine
or naturally whole may be accepted as
"normal and good." •
15
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Ecological Risk Assessment: The applica-
tion of a formal framework, analytical
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 in-
cludes initial hazard identification, expo-
sure and dose-response assessments, and
risk characterization. '
Ecology: The relationship of living things
to one another and their environment, or'
the study of such relationships.
Economic 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 Structure: Attributes related to
the instantaneous physical state of an
ecosystem; examples include species
population density, species richness or
evenness, and standing crop biomass.
Ecosystem: The interacting system of a
biological community and its non-living
environmental surroundings.
Ecotone: A habitat created by the
juxtaposition of distinctly different habi-
tats; an edge habitat; or an ecological zone
or boundary where two or more .ecosys-
tems meet.
Effluenb Wastewater-—treated or un-
treated—that flows out of a treatment
plant, sewer, or industrial outfall.
Generally refers to wastes discharged into
surface waters.
Effluent Guidelines: Technical EPA docu-
ments which set effluent limitations for
given industries and pollutants.
Effluent Limitation: Restrictions estab-
lished by a state or EPA on quantities,
rates, and concentrations in wastewater
discharges.
Effluent Standard: (See effluent limita-
tion.)
Ejecton A device used to disperse a
chemical solutionintowaterbeing treated.
Electrodialysis: A process that uses
electrical current applied to permeable
membranes to remove minerals from
water. Often used to desalinize salty or
brackish water.
Electromagnetic Geophysical Methods:
Ways to measure subsurface conductivity
via low-frequency electromagnetic induc-
tion.
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
16
plates inside the precipitator. Rapping on
the plates causes the particles to fall into a
hopper for disposal.
Eligible Costs: The construction costs for
wastewater treatment works upon which
EPA grants are based.
EMAP Data: Environmental monitoring
data collected under the auspices of the
Environmental Monitoring and Assess-
ment" 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 assur-
ance program.
Emergency (Chemical): A situation creat-
ed by an accidental release or spill of
hazardous chemicals that poses a threat to
the safety of workers, residents, the
environment, or property.
Emergency Episode: (See: air pollution
episode.)
Emergency Exemption: Provision in
FIFRA under which EPA can grant
temporary exemption to a state or another
federal agency to allow the use of a
pesticide product not registered for that
particular use. Such actions involve
unanticipated and/or severe pest prob-
lems where there is not time or interest by
a manufacturer to register the product for
that use. (Registrants cannot apply for
such exemptions.)
Emergency Removal Action: 1. Steps take
to remove contaminated materials that
pose "imminent threats" to local residents
(e.g.,removal of leaking drums or the
excavation of explosive waste.) 2. The
state record of such removals.
Emergency Response Values: Concentra-
tions of chemicals, published by various
groups, defining acceptable levels for
short-term exposures in emergencies.
Emergency Suspension: Suspension of a
pesticide product registration due to an
imminent hazard. The action immediately
halts distribution, sale, and sometimes
actual use of the pesticide involved.
Emission: Pollution discharged into the
atmosphere from smokestacks, other
vents, and surface areas of commercial or
industrial facilities; from residential chim-
neys; and from motor vehicle, locomotive,
or aircraft exhausts.
Emission Cap: Alimit designed to prevent
projected growth in emissions from
existing and future stationary sources
from eroding any mandated reductions.
Generally, such provisions require that
any emission growth from facilities under
the restrictions be offset by equivalent
reductions at other facilities under the
same cap. (See: emissions trading)
Emission Factor: The relationship be-
tween the amount of pollution produced
and the amount of raw material pro-
cessed. 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 legally
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 requirements appli-
cable to other emissions sources. This
allows one source to increase emissions
when another source reduces them,
maintaining an overall constant emission-
level. Facilities that reduce emissions
substantially may "bank" their "credits"
or sell them to other facilities or
industries.
Emulsifier: A chemical that aids in
suspending one liquid in another. Usually
an organic chemical in an aqueous
solution.
Encapsulation: The treatment of asbestos-
containing material with a liquid that
covers the surface With a protective
coating or embeds fibers in an adhesive
matrix to prevent their release into the air.
Enclosure: Putting an airtight, imperme-
able, permanent barrier around asbestos-
containing materials to prevent the release
of asbestos fibers into the air.
End User: Consumer of products for the
purpose of recycling. Excludes products
for re-use or combustion for energy
recovery.
End-of-the-pipe: Technologies -such as
scrubbers on smokestacks and catalytic
converters on automobile tailpipes that
reduce emissions of pollutants after, they
have formed.
End-use Product: A pesticide formulation
for field or other end 'use. The label has
instructions for use or application to
control pests or regulate plant growth.
The term excludes products used to
formulate other pesticide products.
Endangered Species: Animals, birds, fish,
plants, or other living organisms threat-
ened with extinction by anthropogenic
(man-caused) or other natural changes in
their environment. 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
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Priorities LAst and the risks posed to public
health or the environment. EPA or the
• state conducts 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 endangerment assessment
supplements a remedial investigation.
Endriru A pesticide toxic to freshwater.
and marine. aquatic life that produces
adverse health effects in domestic water
supplies.
Energy Management System: A control
•system capable of monitoring environ-
mental and system loads and adjusting
HVAC operations accordingly in order to
conserve energy while maintaining com-
fort. . .'.;.' •••.•'
Energy Management System: A control
system capable of monitoring environ-
mental and system loads and adjusting
HVAC operations accordingly in order to
conserve energy while maintaining com-
fort. •
Energy Recovery: Obtaining energy from
waste through a variety of processes (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 applica-
ble state laws. If a permit has not been
issued, the term includes any requirement
which, in the Regional Administrator's
judgement, would be included in the
permit when issued. Where no permit
applies, the term includes any require-
ment which the RA determines is
necessary for the best practical waste
treatment technology to meet applicable
criteria. ^ V
Enforcement: EPA,, state, or local legal
actions to obtain compliance with environ-
mental laws, rules, regulations, or agree-
ments and/or obtain penalties or criminal
sanctions for violations. Enforcement
procedures may vary, depending on the
requirements of different environmental
laws and related implementing regula-
tions. Under CERCLA, for example, EPA
will seek to require potentially respon-
sible parties to clean up a Superfund site,
or pay for the cleanup, whereas under the
Clean Air Act the Agency may invoke
sanctions against cities railing to meet
ambient^air quality standards that could
prevent certain type's of construction or
federal funding. In other situations, if
investigations by EPA and state agencies
uncover willful violations, criminal trials
and penalties are sought.
Enforcement Decision Document (EDD):
A document that provides an explanation
to the public of EPA's selection of the
cleanup alternative at enforcement sites
on the National Priorities List. Similar to a
Record of Decision. .
Engineered Controls: Method of manag- ;
ing environmental and health- risks by
placing a barrier between the contamina-
tion and the rest of the site, thus limiting
exposure pathways.
Enhanced Inspection and Maintenance
(I&M): An improved automobile inspec-
tion and maintenance program—aimed at
reducing automobile emissions-—that con-
tains, at a minimum, more vehicle types
and model years, tighter, inspection, and
better management practices. It may also
include annual computerized or central-
ized inspections, under-the-hqod inspec-
1 tion—for signs of tampering with pollu-
tion control equipment—and increased
. repair waiver cost. "-•,;. ;
Enrichment: The addition of nutrients
(e.g., nitrogen, phosphorus, carbon com-
,pounds) from sewage effluent or agricul-
tural runoff to surface water, greatly
increases the growth potential for algae
and other aquatic plants.
Entrain: To trap bubbles in water 'either
mechanically through turbulence or che-
mically through a-reaction.
Environment: The sum of all external
conditions affecting the life, development
and survival of an organism.
Environmental Assessment: An environ-
mental 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 environmen-
tal impact statement. -
Environmental Audit: An independent
assessment of the current status of a
party's compliance with applicable envi-
ronmental requirements or of a party's
environmental compliance policies,
practices, and controls.
Environmental/Ecological Risk: The po-
tential for adverse effects on living
organisms associated with pollution of the
environment by effluents, emissions,
wastes, or accidental chemical releases;
energy use; or the depletion of natural
resources.
Environmental Equity/Justice:Equal pro-
tection from_ environmental hazards for
individuals, groups, or communities
regardless of race, ethnicity, or economic
status. This applies to the development,
implementation, and enforcement of
environmental laws, regulations, and
policies, and implies that no population of
people-should be forced to, shoulder a
'disproportionate share of negative
environmental impacts of pollution or
environmental hazard due to a lack of
political or economic strength levels.
Environmental Exposure: Human- expo-
sure to pollutants orginating from facility
emissions. Threshold levels are not
necessarily surpassed, but low-level chro-
nic pollutant exposure is one of the most
common forms of environmental ex-
posure (See: threshold level).
Environmental Fate:. The; destiny of a
chemical of biological pollutant after
release into the environment.
Environmental Fate Data: Data that
characterize a pesticide's fate in the
ecosystem, considering factors that foster
its degradation (light, water, microbes),
pathways and resultant products.
Environmental Impact Statement A
document required of federal agencies by
the National Environmental Policy Act for
major projects or legislative proposals
significantly affecting the environment., 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
of of the state or condition of the
environment. ^
Environmental Lien: A charge, security,
or encumbrance on a property's title to
secure payment of cost or debt arising
from response actions, cleanup, or other
remediation of hazardous substances or
petroleum products.
Environmental Medium: A major envi-
ronmental category that surrounds or
contacts humans, animals, plants, and
other organisms (e.g.,' surface water,
ground water, soil or air) and through
which chemicals of pollutants move. (See:
ambient medium, biological medium.)
Environmental Monitoring for Public
Access and Community Tracking: Joint
EPA,, NOAA, and USGS program to
provide timely and effective communica-
tion of environmental data and infoi;ma-
tion through improved and updated
technology solutions that support timely
environmental • monitoring reporting, -
interpeting, and use of the information for
the benefit of the public. (See: real-time
monitoring.)
Environmental Response Team: EPA
experts located in Edison, N.J., 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 hazardous substances.
Environmental Site Assessment: The
process of determining whether contami-
nation is present on a parcel of real
property. .
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Environmental Sustainability: Long-term
maintenance of ecosystem components
and functions for future generations.
Environmental Tobacco Smoke: Mixture
of smoke from the burning end of a
cigarette, pipe, or cigar and smoke.
exhaled by the smoker. (See; passive
smoking/secondhand smoke.)
Epidemiology: Study of the distribution
of disease, or other health-related states
and events in human populations, as
related to age, sex, occupation, ethnicity,
and economic status in order to identify
and alleviate health problems and pro-
mote better health.
EpilSmnion: Upper waters of a thermally
stratified lake subject to wind action.
Episode (Pollution): An air pollution
incident in a given area caused by a
concentration of atmospheric pollutants
under meteorological conditions that may
result in a significant increase 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 radioactive
series is neither increasing nor decreasing.
Equivalent Method: Any method of
sampling and analyzing for air pollution
which has been demonstrated to the EPA
Administrator's satisfaction to be, under
specific conditions, an acceptable alterna-
tive 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 development,
road building, or logging.
Established Treatment Technologies:
Technologies for which cost and perfor-
mance data are readily available. (See:
Innovative treatment technologies.)
Estimated Environmental Concentra-
tion: The estimated pesticide concentra-
tion in an ecosystem.
Estuary: Region of interaction between
rivers and near-shore ocean waters, where
tidal action and river flow mix fresh and
salt water. Such areas include bays,
mouths of rivers, salt marshes, and
lagoons. These brackish water ecosystems
shelter and feed marine life, birds, and
wildlife. (See: wetlands.)
Ethanol: An alternativce automotive fuel
derived from grain and corn; usually
blended with gasoline to form gasohol.
Ethylene Dibromide (EDB): A chemical
used as an agricultural fumigant and in
certain industrial processes. Extremely
toxic and found to be a carcinogen in
laboratory animals, EDB has been banned
for most agricultural uses in the United
States.
Eutrophic Lakes: Shallow, murky bodies
of water with concentrations of plant
nutrients causing excessive production of
algae. (See: dystrophic lakes.)
Eutrop'hication: The slow aging process
during 'which a lake, estuary, or bay
evolves into a bog or marsh and
eventually 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 sewage
sludge is dumped and dried.
Evapotranspiration: The loss of water
from the soil both by evaporation and by
transpiration from the plants growing 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 delete one or
more of the items required by the Asbestos
Hazard Emergency Response Act (AHER-
A);' e.g., records of previous asbestos
sample collection and analysis may be
used by the accredited inspector in lieu of
' AHERA bulk sampling,
Exclusionary Ordinance: Zoning that
excludes classes ,of persons or businesses
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 bodies
of water defined in the Underground
Injection Control program as aquifers that
are potential sources of drinking water
though not being used as such, and thus
exempted from regulations barring under-
ground injection activities.
Exemption: A state (with primacy) may
exempt a public water system from a
requirement involving a Maximum Con-
taminant Level (MCL), treatment tech-
nique, or both, if the system cannot
comply due to compelling economic or
other factors, or because the system was in
operation before the requirement or MCL
was instituted; and the exemption will not
create a public health risk. (See: variance.)
Exotic Species: A species that is not
indigenous to a region.
Experimental Use Permit: Obtained by
manufacturers for testing new pesticides
or uses thereof whenever they conduct
experimental field studies to support
registration on 10 acres or more of land or
one acre or more of water.
Explosive Limits: The amounts of vapor
in the air that form explosive mixtures;
limits are expressed as lower and upper
limits and give the range of vapor
concentrations in air that will explode if
an ignition source is present.
Exports: In solid waste program, munici-
pal solid waste and recyclables trans-
ported outside the state or locality where
they originated.
Exposure: The amount of radiation or
pollutant present in a given environment,
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 Concentration: The concentra-
tion of a chemical or other pollutant
representing a health threat in a given
environment.
Exposure Indicator: A characteristic of
the environment measured to provide
evidence of the occurrence or magnitude
of a response indicator's exposure to a
chemical or biological stress.
Exposure Level: The amount (concentra-
tion) of a chemical at the absorptive
surfaces of an organism.
Exposure Pathway:The path from sources
of pollutants via, soil, water, or food to
man and other species or settings.
Exposure Route: The way a chemical or
pollutant enters an organism after contact;
i.e., by ingestion, inhalation, or dermal
absorption.
Exposure-Response Relationship: The
relationship between exposure level and
the incidence of adverse effects.
Extraction Procedure (EP Toxic): Deter-
mining toxicity by a procedure which
simulates leaching; if a certain concentra-
tion of a toxic substance can be leached
from a waste, that waste is considered
hazardous, i.e., "EP Toxic."
Extraction Well: A discharge well used to
remove groundwater or air.
Extremely Hazardous Substances: Any
of 406 chemicals identified by EPA as
toxic, and listed under SARA Title III. The
list is subject to periodic revision.
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Fabric Filter: A cloth device that catches '
dust particles from industrial emissions.
Facilities Plans: Plans and studies related
to the construction of treatment works
necessary to comply with the Clean Water
Act or RCRA. A facilities plan investigates
needs and provides information on the
cost-effectiveness of alternatives, a recom-
mended plan, an environmental assess-
ment of the recommendations, and
descriptions of the treatment works, costs,
and a completion schedule.
Facility Emergency Coordinator: Repre-
, sentative of a facility covered by environ-
mental law (e.g, a chemical plant) who
participates in the emergency reporting
process with the Local Emergency Plan-
ning Committee (LEPC).
Facultative Bacteria: Bacteria that can live
under aerobic of anaerobic conditions.
Feasibility Study: I Analysis of the
practicability, of a proposal; e.g., a
description and analysis of potential
cleanup alternatives for a site such as one
on the National Priorities Hist. The
feasibility study usually recommends
selection of a cost-effective alternative. It
usually starts as soon as the remedial
investigation is underway; together, they.
are commonly referred to as the "RI/FS".
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 mammals. 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 quality
standards, used when a,state is unable to
develop an adequate plan.
Federal Motor Vehicle Control Program:
All federal actions aimed at controlling
pollution from motor vehicles by such
efforts as establishing and enforcing •
tailpipe and 'evaporative emission stan-
dards for new vehicles, testing methods
development, and guidance to states
operating inspection and maintenance
programs. , v,
Feedlot: A confined area for the controlled
feeding of animals. Tends to concentrate
large amounts of animal waste that cannot
be absorbed by the soil and, hence, ma^ be
carried to nearby streams or lakes by
rainfall runoff. '.
Fen: A type of wetland that accumulates
peat deposits. Fens are less acidic than
bogs, deriving most of their water from
groundwater rich in calcium and magne-
sium. (See: wetlands.)
Ferrous Metals: Magnetic metals derived
from iron or steel; products made from
ferrous metals include appliances, furni-
ture, containers, and packaging like steel
drums and barrels. - Recycled products
include processing tin/steel 'cans, strap-
ping, and metals from .appliances into
new products.
FlFRA Pesticide Ingredient: An ingre-
dient of a pesticide that must be registered
with EPA under the Federal Insecticide,
Fungicide, arid Rodenticide Act. Products
making pesticide claims 'must register
under FIPRA and may be subject to
labeling and use requirements.
Fill: Man-made deposits of natural soils or
rock products and waste materials.
, 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 consequences.
Filter Strip: Strip or area of vegetation
used for removing sediment, organic
matter, and other pollutants from runoff
and wastewater.
Filtration: A treatment process, under the
control of qualified operators, for re-
moving solid (particulate) matter from
water by means of porous media such as
sand or a man-made filter; often used to
remove particles that contain 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 afterwards as
provided in RCRA regulations.
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 require
preparation of an Environmental Impact
Statement. An FNSI is based on the results
of an environmental assessment.
Finished Water: Water is "finished" when
it 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 contamination
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. '
Fixed-Location Monitoring: Sampling of
an environmental or ambient medium for
pollutant concentration at one location
, continuously or repeatedly.
Flammable: Any material that ignites
easily and will burn rapidly.
Flare: A control device that burns
hazardous, materials to prevent their
release into the environment; may operate
continuously or intermittently, usually on
top of a stack. .
Flash Point: The lowest temperature at
which evaporation of a substance pro-
duces sufficient vapor to form an ignitable
mixture with air. •
Floe: A clump of solids formed in sewage
by biological or chemical action.
Flpcculation: Process by which clumps of
solids in water or sewage aggregate
through biological or chemical action so
they can be separated from water or
sewage. - •
Floodplain: The flat or nearly flat land
along a river or stream or in a tidal area^
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 move-
ment.
Flowable: Pesticide and other formula-
tions in which-the active ingredients are
finely ground insoluble solids suspended
in a liquid. They are mixed with water for
application.
Flowmefer: A gauge indicating the
velocity of wastewater moving through'a
treatment plant or of any liquid moving
.through various industrial processes.
Flue Gas: The air coming out of a chimney
after combustion in .the burner it is
venting. It can include nitrogen oxides,
carbon oxides, water vapor, sulfur oxides,
particles and many chemical pollutants.
. 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.
Fluidized: Amass of solid particles that is
made to flow like a liquid by injection of
water or gas is said to haye been fluidized.
In water treatment, a bed of filter media is
fluidized by backwashing water through
the filter. ,
Fluidized Bed Incinerator: An incinerator
that uses a bed of hot sand or other-
granular material to transfer heat directly
to waste. Used mainly for destroying
municipal sludge.
Flume: A natural or man-made channel
that diverts water.
19
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Fluoridation: The addition of a chemical
to increase the concentration of fluoride
ions in drinking water to reduce the
incidence of tooth decay.
Fluorides: Gaseous, solid, or dissolved
compounds containing fluorine that re-
sult from industrial processes. Excessive
amounts in food can lead to fluorosis.
Fluorocarbons (PCs): Any of a number of
organic compounds analogous to hydro-
carbons in which one or more hydrogen
atoms are replaced by fluorine. 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 ehlorofluorocarbons (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 a system to
clean out piping or tubing, and storage or
process tanks.
Flux: 1. A flowing or flow. 2. A substance
used to help metals fuse-together.
Fly Ash: Non-combustible residual parti-
cles expelled by flue gas.
Fogging: Applying a pesticide by rapidly
heating the liquid chemical so that it forms
very fine droplets that resemble smoke or
fog, Used to destroy mosquitoes, 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.
Food Processing Waste: Food residues
produced during agricultural and indus-
trial operations.
Food Waste: Uneaten food and food
preparation wastes from residences and
commercial establishments such as gro-
cery stores, restaurants, and produce
stands, institutional cafeterias and kitch-
ens, and industrial sources like employee
lunchrooms.
Food Web: The feeding relationships by
which energy and nutrients are trans-
ferred from one species to another.
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 comprising
all active and inert ingredients in a
pesticide.
Fossil Fuel: Fuel drived from ancient
organic remains; e.g., peat/coal, crude oil,
and natural gas.
Fracture: A break in a rock formation due
to structural stresses; e.g., faults, shears,
joints, and planes of fracture cleavage.
Free Product: A petroleum hydrocarbon
in the liquid free" or non aqueous phase.
(See: non-aqueous phase liquid.)
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 con-
tains less than 1,000 milligrams-per-liter
of dissolved solids.
Friable Capable of being crumbled,
pulverized, or reduced to powder by hand
pressure.
Friable Asbestos: Any material con-
taining more than one-percent asbestos,
and that can be crumbled or reduced to
powder by hand pressure. (May include
previously non-friable material which
becomes broken or damaged by mechani-
cal force.)
Fuel Economy Standard: The Corporate
Average Fuel Economy Standard (CAFE)
effective in 1978. It enhanced the national
fuel conservation effort imposing a miles-
per-gallon floor for motor vehicles.
Fuel Efficiency: The proportion of energy
released by fuel combustion 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 environmental
review conducted under the National
Environmental Policy Act (NEPA) A
review is considered functionally equiva-
lent when it addresses the substantive
components of a NEPA review.
Fungicide: Pesticides which are used to
control, deter, or destroy fungi. Fungistat:
A chemical that keeps fungi from
growing.
Fungus (Fungi): Molds, mildews, yeasts,
mushrooms, and puffballs, a group of
organisms lacking in chlorophyll (i.e., are
not photosynthetic) and which are usually
non-mobile, filamentous, and multicellu-
lar. 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.
Furrow Irrigation: Irrigation method in
which water travels through the field by
means of small channels between each
groups of rows.
Future Liability: Refers to potentially
responsible parties' obligations to pay for
additional response activities beyond
those specified in the Record of Decision
or Consent Decree.
Game Fish: Species like trout, salmon, or
bass, caught for sport. Many of them show
more sensitivity to environmental change
than "rough" fish.
Garbage: Animal and vegetable waste
resulting from the handling, storage, sale,
preparation, cooking, and serving of
foods.
Gas Chromatograph/Mass Spectrometer:
Instrument that identifies the molecular
composition and concentrations of vari-
ous chemicals in water and soil samples.
Gasahol: Mixture of gasoline and ethanol
derived from fermented agricultural
products containing at least nine percent
ethanol. Gasohol emissions contain less
carbon monoxide than those from gaso-
line.
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 mixture of
volatile organic compounds.
General Permit: A permit applicable to a
class or category of dischargers.
General Reporting Facility: A facility
having one or more hazardous chemicals
above the 10,000 pound threshold for
planning quantities. Such facilities must
file MSDS and emergency inventory
information with the SERC, LEPC, and
local fire departments.
Generally Recognized as Safe (GRAS):
Designation by the FDA that a chemical or
substance (including certain pesticides)
added to food is considered safe by
experts, and so is exempted from the usual
FFDCA food additive tolerance require-
ments.
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Generator. 1. A. facility 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 regulated medical waste
or whose act first causes such waste to
become subject to regulation. Where more
than one person (e.g., doctors with
separate medical practices) are located in
the same building, each business entity is
a separate generator.
Genetic Engineering: A process of insert-
ing new genetic information into existing
cells i in order to modify a specific
organism for the purpose of changing one
of its characteristics. .
Geographic Information System (GIS):
A computer system designed for storing,
manipulating, analyzing, and displaying
data in a geographic context.
Geological Log: A detailed description of
all underground features (depth, thick-
ness, type of formation) discovered
during the drilling of a well.
Geothermal/Ground Source Heat Pump:
. These heat .pumps are underground coils
to transfer heat from the ground to the
inside of a building. (See: heat pump;
water source heat pump,)
Germicide: Any- compound that kills
disease-causing microorganisms.
Giardia Lamblia: Protozoan in the feces of
humans and animals that can cause severe
gastrointestinal ailments. It is a common
contaminant of surface waters.
• • ~ <
Glass Containers: For recycling purposes,
containers like bottles and jars for drinks,
food, cosmetics and other products. When
being recycled, container glass is gener-
ally separated into color categories for
conversion into new containers, construc-
tion, materials or fiberglass insulation.
Global Warming Potential: The ratio of
the warming caused by a substance to the
warming caused by a 'similar mass of
carbon dioxide. CFC-12, for example, has
a GWP of 8,500; while water has a GWP of
zero. (See: Class I Substance and Class II
Substance.) '
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 to the surround-
ing atmosphere. :
Gooseneck: A portion of a water service
connection between the distribution sys-
tem water main and a meter. Sometimes
called1 a pigtail. •
Grab Sample: A single sample collected at
a particular time and place that represents
the composition of the water, air, or soil
only at that time and place.
Grain Loading: TKe 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. Also used by .municipal water
treatment plantsd. GAC can- be highly
effective in lowerin elevated levels of
radon in water. . :
Grasscycling: Source reduction activities
in which grass clippings are left on the
lawn after mowing. • • , •'
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 com-
posed of wash water from kitchen;
bathroom, and laundry sinks, tubs, .and
washers. ' .'.'-."•.'.'•
Greenhouse Effect: The warming of the
Earth's atmosphere attributed to a buildup
of carbon dioxide or other, gases; some
scientists think that this build-up allows
the sun's rays to heat the Earth, while
making the infra-red radiation, atmo-
sphere opaque to infra-red radiation,
thereby preventing a counterbalancing
.loss of heat.
Greenhouse Gas: A gas, such as carbon
dioxide or methane, which contributes to
potential climate change. . ,'
Grinder Pump: A mechanical device that
shreds solids and raises sewage to a
higher elevation through pressure-sewers.
Gross Alpha/Beta Particle Activity: The
total radioactivity due to alpha or beta
particle emissions as inferred from
measurements on a dry sample. -.
Gross Power-Generation Potential: The
installed power generation capacity that
landfill gas can support.
Ground Cover: Plants grown to keep soil
from eroding. -
Ground-Penetrating Radar: A geophysi-
cal method that uses high frequency
electromagnetic waves to obtain subsur-
face information. •
Ground Water: The supply of fresh water
found beneath the Earth's surface, 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 leach-
ing agricultural or industrial pollutants or
leaking underground storage tanks.
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 microorgarums/ aigae, or large-
diameter pathogens; 2. significant and
relatively rapid shifts in water
characteristcs such as turbidity, tempera-
ture, conductivity, or pH which closely
correlate to clirriatological or surface
water conditions. Direct influence is
determined for individual sources - in
.accordance with criteria established by a
state. •
Ground-Water Discharge: Ground water
entering near coastal waters which has
been contaminated by landfill leachate,
deep well injection of hazardous wastes,
septic tanks, etc. ,
Ground-Water Disinfection Rule: A1996
amendment of the Safe Drinking Water
Act requiring EPA to promulgate national
primary drinking water regulations re-
quiring disinfection as for all public water
systems/ including surface waters and
ground water systems.
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 equip-
ment are considered gullies.
H
Habitat Indicator: A physical attribute of
the environment measured to characterize
conditions necessary to support an
organism, population, or community in
the absence of pollutants; e.g., salinity of
estuarine waters or substrate .type in
streams or lakes.
Habitat: The place where a population
(e.g., human, animal, plant, microorgan-
ism) lives and its surroundings, both
living and non-living.
Half-Life: 1. The time required for a
pollutant to lose one-half of its original
concentraton. For example, the biochemi-
cal half-life of DDT in the environment is
15 years. 2. The time required for half of
the atoms of a radioactive element to
undergo self-transmutation or decay
(half-life of radium is 1620 years). 3. The
time required for the elimination of half a
total dose from the body.
Halogen: A type of incandescent lamp
with higher energy-efficiency that stan-
dard ones.
Halon: Bromine-containing compounds
with long atmospheric lifetimes whose
breakdown in the stratosphere causes
depletion of ozone. Halons are used in
firefighting. '
Hammer Mill: 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
21
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industrial processes and prevent soap
from sudsing.
Hauler: Garbage collection company that
offers complete refuse removal service;
many will also collect recyclables.
Hazard: 1. Potential for radiation, a
chemical or other pollutant to cause
human illness or injury. 2. In the pesticide
program, the inherent toxicity of a
compound. Hazard identification of a
given substances is an informed judgment
based on verifiable toxicity data from
animal models or human studies.
Hazard Assessment: Evaluating the ef-
fects of a stressor or determining a margin
of safety for an organism by comparing
the concentration which causes toxic
effects with an estimate of exposure to the
organism.
Hazard Communication Standard: An
OSHA regulation that requires chemical
manufacturers, suppliers, and importers
to assess the hazards of the chemicals that
they make, supply, or import, and to
inform employers, customers, and work-
ers' of these hazards through MSDS
information.
Hazard Evaluation: A component of risk
evaluation that involves gathering and
evaluating data on the types of health
injuries or diseases that may be produced
by a chemical and on the conditions of
exposure under which such health effects
are produced.
Hazard Identification: Determining if a
chemical or a microbe can cause adverse
health effects in humans and what those
effects might be.
Hazard Quotient: The ratio of estimated
site-specific exposure to a single chemical
from a site over a specified period to the
estimated daily exposure level, at which
no adverse health effects are likely to
occur.
Hazard Ratio: A term used to compare an
animal's daily dietary intake of a pesticide
to its LD50 value. A ratio greater than 1.0
indicates that the animal is likely to
consume an a dose amount which would
kill 50 percent of animals of the same
species. (See: LD50/Lethal Dose.)
Hazardous Air Pollutants: Air pollutants
which are not covered by ambient air
quality standards but which, as defined in
the Clean Air Act, may present a threat of
adverse human health effects or adverse
environmental effects. Such pollutants
include asbestos, beryllium, mercury,
benzene, coke oven emissions, radionu-
clides, and vinyl chloride.
Hazardous Chemical: An EPA designa-
tion for any hazardous material requiring
an MSDS under OSHA's Hazard
Communication Standard. Such sub-
22
stances are capable of producing fires and
explosions or adverse health effects like
cancer and dermatitis. Hazardous chem-
icals are distinct from hazardous
waste.(See: Hazardous Waste.)
Hazardous Ranking System: The princi-
pal screening tool used by EPA to evaluate
risks to public health and the environment
associated with abandoned or uncon-
trolled 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 human
population. This score is the primary
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 hazardous
substances are toxic, corrosive, ignitable,
explosive, or chemically reactive. 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 is otherwise released into
the environment.
Hazardous Waste: By-products of society
that can pose a substantial or potential
hazard to human health or the environ-
ment when improperly managed. Pos-
sesses at least one of four characteristics
'(ignitability, corrosivity, .reactivity, or
toxicity), or appears on special EPA lists.
Hazardous Waste Landfill: An excavated
or engineered site where hazardous waste
is deposited and covered.
Hazardous Waste Minimization: Reduc-
ing the amount of toxicity or waste
produced by a facility via source reduction
or environmentally sound recycling.
Hazards Analysis: Procedures used to (I)
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 hazardous materials; and (3)
compare hazards to determine which
present greater or lesser risks to a
community.
Hazards Identification: Providing infor-
mation on which facilities have extremely
hazardous substances, what those chemi-
cals are, how much there is at each facility,
how the chemicals are stored, and
whether they are used at high tempera-
tures.
Headspace: The vapor mixture trapped
above a solid or liquid in a sealed vessel.
Health Advisory Level: A non-regulatory
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 Assessment: 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 (ATSDR)
of the Department of Health and Human
Services (DHHS) is required to perform
such an assessment at every site on the
National! Priorities List.
Heat Island Effect: A "dome" of elevated
temperatures over an urban area caused
by structural and pavement heat fluxes,
and pollutant emissions.
Heat Pump: An electric device with both
heating and cooling capabilities. It ex-
tracts heat from one medium at a lower
(the heat source) temperature and trans-
fers it to another at a higher temperature
(the heat sink), thereby cooling the first
and warming the second. (See: geother-
mal, water source heat pump.)
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 in 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 illegally fed
treated seed.
Herbicide: A chemical pesticide designed
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 End Exposure (dose) Estimate: An
estimate of exposure, or dose level
received anyone in a defined population
that is greater than the 90th percentile of
all individuals in that population, but less
than the exposure at the highest percentile
in that population. A high end risk
descriptor is an estimate of the risk level
for such individuals. Note that risk is
based on a combination of exposure and
susceptibility to the stressor.
High Intensity Discharge: A generic term
for mercury vapor, metal halide, and high
pressure sodium lamps and fixtures.
High-Density Polyethylene: A material
used to make plastic bottles and other
products that produces toxic fumes when
burned.
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High-Level Nuclear Waste 'Facility. Plant
designed to handle disposal of used
nuclear fuel, high-level radioactive waste,
and plutonium waste.
High-Level Radioactive Waste (HLRW):
Waste generated in core fuel of a nuclear
reactor, found at nuclear reactors or by
nuclear fuel reprocessing; is • a serious
threat to anyone who comes near the
waste without shielding. (See: low-level
radioactive 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 exposure/health haz-
ards which1 may result in high levels of
exposure to contaminants or pollutants.
High-to-Low-Dose -Extrapolation: The
process of prediction of low exposure risk
to humans and animals from the mea-
sured , high-exposure-high-risk data in-
• volving laboratory animals.
Highest Dose Tested: The highest dose of
a chemical or substance tested in a study.
Holding Pond: A pond or reservoir,
usually made of earth, built to store
polluted runoff.
Holding Time: The maximum amount of
time a sample may be stored before
analysis.
Hollow Stem Auger Drilling: Conven-
tional drilling method that uses augurs to
penetrate the soil. As the augers are
rotated, soil cuttings are conveyed to the
ground surface via augur spirals. DP tools
can be used inside the hollow augers.
Homeowner Water System: Any water
system which supplies piped water to a
•single residence.
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
directed 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 transplanted. 2.
In medicine, an animal infected or
parasitized by another organism.
Household Hazardous Waste: Hazardous
products ' used and disposed of by
residential as opposed to industrial
consumers. Includes paints, stains, var-
nishes, .solvents, pesticides, and other
materials or products containing volatile
chemicals that can catch fire, react or
explode, or that are corrosive or toxic.
Household Waste (Domestic Waste):
.Solid waste, composed of garbage and
rubbish, which normally originates in a
private home or apartment house. Do-
mestic waste may contain a significant
amount of toxic or hazardous waste.
Human Equivalent Dose: A dose which,
when administered to humans, produces
an effect equal to that produced by a dose
in animals, •
Human Exposure Evaluation: Describing
the nature and size of the population exposed
to a substance and the mangnitude and
duration of their exposure.
Human Health Risk: The likelihood that a
given exposure or series of exposures may
have damaged or will damage the health
of individuals.
Hydraulic Conductivity: The rate at
which water can move through a
permeable medium, (i.e., the coefficient of
permeability.)
Hydraulic Gradient In general, the
direction of groundwater flow • due to
changes in* the depth of the water table.
Hydrocarbons (HC): Chemical /com-
pounds that consist entirely of carbon and
hydrogen.
Hydrogen Sulfide (H2S): 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 atmosphere
and earth. '•••.•
Hydrology: The science dealing with the
properties, distribution, and circulation of
water. -
Hydrolysis: The decomposition of or-
ganic compounds by interaction with
water.
Hydronic: A ventilation system using
heated or cooled water pumped through a
building. : ,
Hydrophilic: Having a strong affinity for
water.
Hydrophobic: Having a strong aversion
for water.
Hydropneumatic: A water system, usu-
ally small, in which a water pump is
automatically controlled by the pressure
in a compressed air tank.
Hypersensitivity Diseases:Diseases char-
acterized by allergic responses to pollut-
ants; diseases most clearly associated with
• indoor air quality are asthma, rhinitis, and
pneumonic hypersensitivity.
Hypolimnion: Bottom waters of a thermal-
ly stratified lake. The hypolimnion of a
eutrophic lake is usually low or lacking in
oxygen.
Hypoxia/Hypoxic Waters: Waters with
dissolved oxygen concentrations -of less
than 2 ppm, the level generally accepted
as the minimum required for most marine
life to survive and reproduce.
I
Identification Code or EPA I.D. Number:
The unique code assigned to each
generator, transporter, and treatment,
storage, or disposal facility by regulating
agencies to facilitate identification and
tracking of chemicals or hazardous waste.
Ignitable: Capable of burning or causing
a fire. ,
IM240: A high-tech, transient dynamom-
eter automobile emissions test that takes
up to 240 seconds.
Imhoff Cone A clear, cone-shaped
.container used to measure the volume of
settleable solids in, a specific volume of
water. •
Immediately Dangerous to Life and
Health (IDLH): The maximum level to
which a healthy individual can be
exposed to a chemical for 30 minutes and
escape without suffering irreversible
health effects or impairing symptoms.
Used as a "level of concern."'(See: level of
concern.)
Imminent Hazard: One that would likely
result in unreasonable adverse effects oh
humans or the environment or risk
unreasonable hazard to an endangered
species during the time required for a
pesticide registration cancellation pro-
ceeding.
Imminent Threat: A high probability that
exposure is occurring.
Immiscibility: The inability of two or
more substances or liquids to readily
dissolve into one another, such as soil and
water.
Impermeable: Not easily penetrated. The
property of a material or soil that does not
allow, or allows only with great difficulty,
the movement or passage of water.
Imports: Municipal solid waste and
recyclables that have been transported to a
state or locality for processing or final
disposition (but that did not originate in
that state or locality).
23
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Impoundment: Abody of water or sludge
confined by a dam, dike, floodgate, or
other barrier,
In Situ: In its original place; unmoved
unexcavated; remaining at the site or in
the subsurface.
In-Line Filtration: Pre-treatment method
in which chemicals are mixed by the
flo%ving water; commonly used in pres-
sure filtration installations. Eliminates
need for flocculation and sedimentation.
In-Situ Flushing: Introduction of large
volumes of water, at times supplemented
with cleaning compounds, into soil,
waste, or ground water to flush hazardous
contaminants from a site.
In-Situ Oxidation: Technology that oxi-
dizes contaminants dissolved in ground
water, converting them into insoluble
compounds.
In-Situ Stripping: Treatment system that
removes or "strips" volatile organic
compounds from contaminated ground or
surface water by forcing an airstream
through the water and causing the
compounds to evaporate.
In-Situ Vitrification: Technology that
treats contaminated soil in place at
extremely high temperatures, at or more
than 3000 degrees Fahrenheit.
In Vitro: Testing or action outside an
organism (e.g., inside a test tube or
culture dish.)
In Vivo: Testing or action inside an
organism
Incident 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 equip-
ment.
Incident 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 emergency
incident site, backed by an Emergency
Operations Center staff with resources,
information, and advice.
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 residues to a safe,
non-burnable ash that can be disposed of
safely on land, in some waters, or in
underground locations.
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 unsuitable
for mixing with another waste or material
because it may react to form a hazard.
Indemnification: In the pesticide pro-
gram, legal requirement that EPA pay
certain end-users, dealers, and distribu-
tors for the cost of stock on hand at the
time a pesticide registration is suspended.
Indicator: In biology, any biological entity
or processies, or community whose
characteristics show the presence of
specific environmental 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
measurement; e.g., a pressure guage or a
moveable scale.
Indirect Discharge:Introduction of pollut-
ants 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 building,
property, road or parking area tthat
attracts motor vehicle traffic and, indi-
rectly, causes pollution.
Indoor Air: The breathable air inside a
habitable structure or conveyance.
Indoor Air Pollution: Chemical, physical,
or biological contaminants in indoor air.
Indoor Climate: Temperature, humidity,
lighting, air flow and noise levels in a
habitable structure or conveyance. Indoor
climate can affect indoor air pollution.
Industrial Pollution Prevention: Combi-
nation of industrial source reduction and
toxic chemical use substitution.
Industrial Process Waste: Residues pro-
duced during manufacturing operations.
Industrial Sludge: Semi-liquid residue or
slurry remaining from treatment^ of
industrial water and wastewater.
Industrial Source Reduction: Practices
that reduce the amount of any hazardous
substance, pollutant, or contaminant
entering any waste stream or otherwise
released into the environment Also
reduces the threat to public health and the
environment associated with such re-
leases. Term includes equipment or
technology modifications, substitution of
raw materials, and improvements in
housekeeping, maintenance, 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, dispersants, and
surfactants that are not active against
target pests. Not all inert ingredients are
innocuous.
Inertial Separator: A device that uses
centrifugal force to separate waste parti-
cles.
Infectious Agent: Any organism, such as
a pathogenic virus, parasite, or or
bacterium, that is capable of invading
body tissues, multiplying, and causing
disease.
Infectious Waste: Hazardous waste ca-
pable of causing infections in humans,
including: contaminated animal waste;
human blood and blood products; isola-
tion waste, pathological waste; and
discarded sharps (needles, scalpels or
broken medical instruments).
Infiltration: 1. The penetration of water
through the ground surface into sub-
surface soil or the penetration of water
from the soil into sewer or other pipes
through defective joints, connections, or
manhole walls. 2. The technique of
applying large volumes of waste water to
land to penetrate the surface and percolate
through the underlying soil. (See: percola-
tion.)
Infiltration Gallery:Asub-surface ground-
water collection system, typically shallow
in depth, constructed with open-jointed or
perforated pipes that discharge collected
water into a watertight chamber from
which the water is pumped to treatment
facilities and into the distribution system.
Usually located close to streams or ponds.
. Infiltration Rate: The quantity of water
that 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 Collection Request (ICR): A
description of information to be gathered
in connection with rules, proposed rules,
surveys, and guidance documents that
contain information-fathering require-
ments. The ICR describes what informa-
tion is needed, why it is needed, how it
will be collected, and how much collecting
it will cost. The ICR is submitted by the
EPA to the Office of Management and
Budget (OMB) for approval.
•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.
Inhalable Particles: All dust capable of
entering the human respiratory tract.
Initial Compliance Period (Water): The
first full three-year compliance period
24
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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.
Innovative Technologies: New or inven-
tive methods to treat effectively hazard-
ous waste and reduce risks to human
health and the environment.
Inoculum: 1. Bacteria or fungi injected-
into'compost to start biological action. 2.A
medium containing organisms, usually
bacteria or a virus, that is introduced into
cultures or living organisms.
Inorganic Chemicals: Chemical sub-
stances of mineral origin, not of basically
carbon structure.
Insecticide: Apesticide compound specifi-
cally used to kill or prevent the growth of
insects. . • -
Inspection and Maintenance (I/M): 1.
Activities to ensure that vehicles' emission
controls work properly. 2. Also applies to
wastewater treatment jSlants and other
anti-pollution facilities and processes.
Institutional Waste: Waste generated, at
institutions such as schools, libraries,
hospitals, prisons, etc.
Instream Use: Water use taking place
within a .stream channel; e.g., hydro-
electric power generation, navigation,
water quality improvement, fish propaga-
tion, recreation,
Integrated Exposure Assessment: Cumu-
lative summation (over time) of the
magnitude of exposure to a toxic chemical
in all media.
Integrated Pest Management (IPM): A
mixture of chemical and other, non-
pesticide, methods to control pests.
Integrated Waste Management: Using a
variety of practices to handle municipal
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 sewage to
flow, directly into a receiving stream, thus
keeping it from overflowing onto the
streets. Also used in separate 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.
Interfacial Tension: The strength of-the
film separating two immiscible fluids
(e.g., oil and water) measured in dynes
per, or millidynes per centimeter.
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 circumstances are
usually called "Part A" or "Part B"
permits. ...
Internal Dose: In exposure assessment,
the amount of a substance penetrating the
absorption barriers (e.g., skin,, lung
tissue, gastrointestinal tract) of an organ-
ism through either physical of biological
processes. (See: absorbed dose)
Interstate Carrier Water Supply: A source
of water for drinking and sanitary 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 example, the U.S.
Supreme Court has ruled that states may
not inequitably restrict the disposal of
out-of-state wastes in their jurisdictions.
Interstate Waters: Waters that flow across
or ,form part of state or international
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.,.
Intrastate Product: Pesticide products
once registered by states for sale and use
only in the state. All intrastate products
have been converted to full federal
registration or canceled. -
Inventory (TSCA): Inventory of chemi-
cals produced pursuant to Section 8 (b) of
the Toxic Substances Control Act.
Inversion: A layer of warm air that
prevents the rise of cooling air and traps
pollutants beneath it; can cause an air
pollution episode.
Ion: An electrically charged atom or group
of atoms. . \
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 hydrox-
ide to increase the pH to a level where the
metals will precipitate out.
lonization Chamber: A device that
measures the intensity of ionizing radia-
tion. .
Ionizing Radiation: Radiation that can
strip electrons from atoms; e.g., alpha,
beta, and gamma radiation.
IRIS: EPA's integrated Risk Information
System, an electronic data base containing
the Agency's latest descriptive and
quantitative regulatory 'information on
chemical constituents.
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 visible
light (gamma, x-ray, or ultraviolet), for •
medical purposes, to sterilize milk or
other foodstuffs, or to induce polymer-
ization of monomers or vulcanization of
rubber.
Irreversible Effect Effect characterized
v by the inability of the body to partially oor
fully repair injury caused by a toxic agent.
Irrigation: Applying water or wastewater
to land areas to supply the water and
nutrient needs of plants.
Irrigation Efficiency: The amount of
water stored in the crop root zone
compared to the amount of irrigation
water applied.
Irrigation Return Flow: Surface and
subsurface water which leaves the field
following application of irrigation water.
Irritant A substance that can cause
irritation of the skin, eyes, or respiratory
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.
Isoconcentration: More than one sample
point exhibiting the same isolate concen-
tration. '
Isopleth: The line or area represented by
an isoconcentratiori.
Isotope: A variation of an element that has
the same atomic number of protons but a
different weight because of the number of
neutrons. Various isotopes of the same
element may have different radioactive
behaviors, some are highly unstable.
Isotropy: The condition in which the
hydraulic or other properties of an aquifer
are the same in all directions.
J
Jar Test A laboratory procedure that
simulates a water treatment plant's
coagulation/flocculation units with dif-
fering chemical doses, mix speeds, and
. settling times to estimate the minimum or
• ideal coagulant dose required to achieve
certain water quality goals.
Joint and Several Liability: Under
CERCLA, this legal concept relates to the
liability for Superfund site cleanup and
25
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other costs on the part of more than one
potentially responsible party (i.e., if there
were several owners or users of a site that
became contaminated over the years, they
could all be considered potentially liable
for cleaning up the site.)
K
Karst: A geologic formation of irregular
limestone deposits with sinks, under-
ground streams, and caverns.
Kinetic Energy: Energy possessed by a
moving object or .water body.
Kinetic Rate Coefficient: A number that
describes the rate at which a water
constituent such as a biochemical oxygen
demand or dissolved oxygen rises or falls,
or at whuch an air pollutant reacts.
Laboratory Animal Studies: Investiga-
tions using animals as surrogates for
humans.
Lagoon: 1 A shallow pond where
sunlight, 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 wastewa-
ter 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 amend-
ments.
Land Disposal Restrictions: Rules that
require hazardous wastes to be treated
before disposal on land to destroy or
immobilize hazardous constituents that
might migrate into soil and ground water.
Land Farming (of Waste): A disposal
process in which hazardous waste de-
posited on or in the soil is degraded
naturally by microbes.
Landfills: 1. Sanitary landfills are dispos-
al 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 chemical landfills
are disposal sites for hazardous waste,
selected and designed to minimize the
chance of release of hazardous substances
into the environment.
Landscape: The traits, patterns, and
structure of a specific geographic area,
including its biological composition, its
physical environment, and its anthropo-
genic or social patterns. An area where
interacting ecosystems are grouped and
repeated in similar form.
Landscape Characterization: Documenta-
tion of the traits and patterns of the
essential elements of the landscape.
Landscape Ecology: The study of the
distribution patterns of communities and
ecosystems, the ecological processes 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. Land-
scape indicators may be useful as
measures of certain kinds of environmen-
tal degradation such as forest frag-
mentation.
Langelier Index (LI): An index reflecting
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 percent of
the nation's hazardous waste, and are
subject to all RCRA requirements.
Large Water System: A water system that
services more than 50,000 customers.
Laser Induced Fluorescence: A method
for measuring the relative amount of soil
and/or groundwater with an in situ
sensor.
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.
Laundering Wee Sedimention basin
overflow weir.
LC 50/Lethal Concentration: Median
level concentration, a standard measure
of toxicity It tells how much of a substance
is needed to kill half of a group of
experimental organisms in a given time.
LC 50/Lethal Dose: The dose of a toxicant
or microbe that will kill 50 percent of the
test organisms within a designated
period. The lower the LD50, the more toxic
the compound.
Ldlo: Lethal dose low; the lowest dose in
an animal study at which lethality occurs.
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.
Leaching: 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
hazardous to health if breathed or
swallowed. Its use in gasoline, paints, and
plumbing compounds has been sharply
restricted or eliminated by federal laws
and regulations. (See: heavy metals.)
Lead Service Line: A service-line made of
lead which connects the water to the
building inlet and any lead fitting
connected to it.
Legionella: A genus of bacteria, some
species of which have caused a type of
pneumonia called Legionaires Disease.
Level of Concern (LOC): The concentra-
tion in air of an extremely hazardous
substance above which there. may be
serious immediate health effects, to
anyone exposed to it for short periods. ,
Life Cycle of a Product: All stages of a
product's development, from extraction of
fuel for power to production, marketing,
use, and disposal.
Lifetime Average Daily Dose: Figure for
estimating excess lifetime cancer risk.
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.
Lifting Station: (See: pumping station.)
Light Non-Aqueous Phase Liquid
(LNAPL): A non-aqueous phase liquid
with a specific gravity less than 1.0.
Because the specific gravity of water is 1.0,
most LNAPLs float on top of the water
table. Most common petroleum hydrocar-
bon fuels and lubricating oils are LNAPLs.
Light-Emitting Diode: A long-lasting
illumination technology used for exit
signs which requires very little power.
Limestone Scrubbing: Use of a limestone
and water solution to remove gaseous
stack-pipe sulfur before it reaches the
atmosphere.
Limit of Detection (LOD): The minimum
concentration of a substance being ana-
lyzed test that has a 99 percent probability
of being identified.
Limited Degradation: An environmental
policy permitting some degradation, of
natural systems but terminating at a level
26
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•well beneatK an establisked Health, stan-
dard.
Limiting Factor: .'A condition whose
absence 'or excessive concentration, is
incompatible with the needs or tolerance
of a species or population and which may
have a negative influence on their ability
to thrive. ' ,
Limnology: The study of the physical,
chemical, hydrological, and biological
aspects of'fresh water bodies.
Lindane: A pesticide that causes adverse
health effects in domestic water supplies
and is toxic to freshwater fish and aquatic
life. • -
Liner: 1. A relatively impermeable barrier
designed to keep leachate inside a landfill.
Liner materials include plastic and dense
clay. 2. An insert or sleeve for sewer pipe's
to prevent leakage or .infiltration.
Lipid Solubility: The maximum concen-
tration of a chemical that will dissolve in;
fatty substances. Lipid soluble substances
are insoluble 'in water. They will very
selectively disperse through the environ-
ment via uptake in living tissue,
Liquefaction: Changing a solid into a
liquid. .
, Liquid Injection Incinerator: Commonly
used; system that relies on high pressure to
prepare liquid wastes for incineration by
breaking them up into tiny droplets to
allow easier combustion.
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 Wafer Acts. The list is.
maintained by The Office of Enforcement
and Compliance Monitoring.
Listed Waste:. Wastes listed as hazardous
under RCRA but which have not been
subjected to the Toxic Characteristics
Listing Process because the dangers they
•present are considered self-evident.
Lithology: Mineralogy, grain size, texture,
and other physical properties of granular
soil, sediment, or rock. -
Litter 1. The highly visible portion of
solid waste carelessly discarded-outside
the regular garbage and trash collection
and disposal system. 2. leaves and twigs
fallen from forest trees. .
Littoral Zone: 1. That portion of a body of
fresh water extending from the shoreline
lakeward to the limit of occupancy 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 contract for educa-
tional services, including primary and
secondary public and private schools. A
single, unaffiliated school can be consid-
ered an LEA for AHERA purposes.
Local Emergency Planning Committee
(LEPC): A committee appointed by the
state emergency response commission, as
required by SARA Title III, to formulate a
comprehensive emergency plan for its
jurisdiction. . •
Low Density Polyethylene (LOPE): Plas-
tic material used for both rigid containers
and plastic film applications.
Low Emissivity (low-E) Windows: New
window technology that lowers the
amount of energy loss through windows
by inhibiting the transmission of radiant
heat while still allowing sufficient light to
pass through.
Low NOX Burners: One of several
combustion technologies used to reduce
emissions of Nitrogen Oxides (NOX.) "
Low-Level Radioactive Waste (LLRW):
Wastes, less hazardous than most of those
associated with a nuclear reactor; gener-
ated by hospitals, research laboratories,
.and certain industries. The Department of
Energy, Nuclear Regulatory Commission,
and EPA share responsibilities for manag-
ing them. (See: high-level radioactive
wastes.) ' •
Lower Detection Limit: The smallest
signal above background
noise an instrument can reliably detect.
Lower Explosive Limit (LEL): The con-
centration of a compound in air. below ,
which the mixture will not catch on fire.
Lowest Acceptable Daily Dose: The
largest quantity of a chemical that will not
cause a toxic effect, as determined by
animal studies.
Lowest Achievable Emission Rate: Un- •
der the Clean At Act, the rate of
'emissions that "reflects (1) the most
stringent emission limitation in the
implementation 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 practice,
whichever is more stringent. A proposed
new or modified source may not emit
pollutants in excess of existing new source
standards.
Lowest Observed Adverse Effect Level
(LOAEL): The lowest level of a stressor
that causes statistically and biologically
significant differences in test samples as
compared to other samples subjected to no
stressor. .
.
Macropores: Secondary soil features such
as root holes or desiccation cracks that can
create significant conduits for movement
of NAPL and dissolved contaminants, or
vapor-phase contaminants;
Magnetic Separation: Use of magnets to
separate ferrous materials from mixed
municipal waste stream.
Major Modification: This term is used to
define modifications of major stationary
sources of emissions With respect to
Prevention of Significant Deterioration
and New Source Review under the Clean
Air Act.
Major Stationary Sources: Term used to
determine the applicability of Prevention
of Significant Deterioration and new
source regulations. In a nonattainment
area, any stationary pollutant source with
, potential to emit more than 100 tons per
year is considered 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 treatment
works (POTWs) with flows equal to at
least one million gallons per day (mgd) or
servicing a population equivalent to
10,000 persons; certain other , POTWs
having significant water quality impacts. '»
(See: minors.)
Man-Made (Anthropogenic) Beta Par-
ticle ' and Photon Emitters: All radio-
nuclides emitting beta particles and/or .,
photons listed in Maximum Permissible'
Body Burdens and Maximum Permissible
Concentrations of Radonuclides un Air
and Water for OccupationalExposure.
Management Plan: Under the Asbestos
Hazard Emergency Response Act (AHER-.
A), a document that each Local Education
Agency is required to prepare, describing
all activities planned and undertaken by a
school to comply with AHERA regu- ,
lations, including building inspections to'
identify , asbestos-containing materials,
response actions, and operations and
maintenance'programs to minimize the
risk of exposure.
Managerial Controls: Methods of
nonpoint source, pollution control based
on decisions about managing agricultural
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.
Manifest A one-page form used by ,
haulers transporting waste that lists EPA
identification numbers, type and quantity
of waste, the generator it originated from,
the transporter that shipped it, and the
27
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storage or disposal facility to which it is
being shipped. It includes copies for all
participants in the shipping process.
Manifest System: Tracking of hazardous
waste from "cradle-to-grave" (generation
through disposal) with accompanying
documents known as manifests.(See:
cradle-to-grave.)
Manual Separation: Hand separation of
compostable or recyclable material from
waste.
Manufacturer's 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.
Manufacturing Use Product: Any prod-
uct intended (labeled) for formulation or
repackaging into other pesticide products.
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.
Margin of Exposure (MOE): The ratio of
the no-observed adverse-effect-level to
the estimated exposure dose.
Marine Sanitation Device: Any equip-
ment or process installed on board a vessel
to receive, retain, treat, or discharge
sewage.
Marsh: A type of wetland that does not
accumulate appreciable peat deposits and
is dominated by herbaceous vegetation.
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, surfac-
ing material, and miscellaneous material.
Material Safety Data Sheet (MSDS): A
compilation of information required un-
der the OSHA Communication Standard
on the identity of hazardous chemicals,
health, and physical hazards, exposure
limits, and precautions. Section 311 of
SARA requires facilities to submit MSDSs
under certain circumstances.
Material Type Classification of suspect
material by its specific use or application;
e.g., pipe insulation, fireproofing, and
floor tile.
Materials Recovery Facility (MRF): A
facility that processes residentially col-
lected mixed recyclables into new prod-
ucts available for market.
Maximally (or Most) Exposed Indi-
vidual: The person with the highest
exposure in a given population.
Maximum Acceptable Toxic Concentra-
tion: For a given ecological effects test, the
range (or geometric mean) between the
No Observable Adverse Effect Level and
the Lowest Observable Adverse Effects
Level.
Maximum Available Control Technology
(MACT): The emission standard for
sources of air pollution requiring the
maximum reduction of hazardous emis-
sions, taking cost and feasibility into
account. Under the Clean Air Act
Amendments of 1990, the MACT must not
be less than the average emission level
achieved by controls on the best perform-
ing 12 percent of existing sources, by
category of industrial and utility sources.
Maximum Contaminant Level: The maxi-
mum permissible level of a contaminant
in water delivered to any user of a public
system. MCLs are enforceable standards.
Maximum Contaminant Level Goal
(MCLG): Under the Safe Drinking Water
Act, a non-enforceable concentration of a
drinking water contaminant, 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; maxi-
mum contaminantlevel.)
Maximum Exposure Range: Estimate of
exposure or dose level received by an
individual in a defined population that is
greater than the 98th percentile dose for all
individuals in that population, but less
than the exposure level received by the
person receiving the highest exposure
level.
Maximum Residue Level: Comparable to
a U.S. tolerance level, the Maximum
Residue Level the enforceable limit on
food pesticide levels in some countries.
Levels are set by the Codex Alimentarius
Commission, a United Nations agency
managed and funded jointly by the World
Health Organization and the Food and
Agriculture Organization.
Maximum Tolerated Dose: The maxi-
mum dose that an animal species can
tolerate for a major portion of its lifetime
without significant impairment or toxic
effect other than carcinogenicity.
Measure of Effect/Measurement End-
point A measurable characteristic of
ecological entity that can be related to an
assessment endpoint; e.g., a laboratory
test for eight species meeting certain
requirements may serve as a measure of
effect for an assessment endpoint, such as
survival of fish, aquatic, invertebrate or
algal species under acute exposure.
Measure of Exposure: A " measurable
characteristic of a stressor (such as the
specific amount of mercury in a body of
water) used to help quantify the exposure
of an ecological entity or individual
organism.
Mechanical Aeration: Use of mechanical
energy to inject air into water to cause a
waste stream to absorb oxygen. .
Mechanical Separation: Using mechani-
cal means to separate waste into various
components.
Mechanical Turbulence: Random irregu-
larities of fluid motion in air caused by
buildings or other nonthermal, processes.
Media: Specific environments—air, water,
soil—which are the subject of regulatory
concern and activities.
Medical Surveillance: Aperiodic compre-
hensive review of a worker's health
status; acceptable elements of such
surveillance program are listed in the
Occupational Safety and Health Admin-
istration 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 (b)(l).
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 (Hg): Heavy metal that can
accumulate in the environment and is
highly toxic if breathed or swallowed.
(See: heavy metals.)
Mesotrophic: Reservoirs and lakes which
contain moderate quantities of nutrients
and are moderately productive 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. A
major component of natural gas used in
the home.
Methanol: An alcohol that can be used as
an alternative fuel or as a gasoline
additive. It is less volatile than gasoline;
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. Poisonous to
humans and animals if ingested.
28
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Method 18: An EPA test method which
uses gas chromatographic techniques to
measure the concentration of volatile
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. , '
Method Detection Limit (MDL): See limit,
of detection.
Methoxychlor: Pesticide that causes ad-
verse health effects in doernstic water
supplies and is toxic to freshwater and
marine aquatic life. (
Methyl 'Orange Alkalinity: A measure of
the total alkalinity in a water sample in
which the color of methyl orange reflects
the change in level. , ..
Microbial Growth: The amplification or
multiplication of microorganisms such as
bacteria, algae, diatoms, plankton, and
fungi.
Microbial' Pesticide: A microorganism
that is used to kill a pest, but is of
minimum toxicity to humans. ,
Microclimate: I. Localized climate condi-
tions within an urban area or neighbor-
hood. 2. The climate around a tree or shrub
or a stand of trees. ' . ' , •
Microenvironmental Method: A method
,.' for sequentially assessing exposure for a
series of microenyironments that can be
approximated by constant concentrations
.of a stressor. •
Microenvironments: Well-defined sur-
roundings such as the home, office, or
kitchen that can be treated as uniform in
terms of stressor concentration.
Million-Gallons Per Day (MGD): A
measure of water flow.
Minimization: A comprehensive program
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.
Mining Waste: Residues resulting from
the extraction of raw materials from the
earth.
Minor Source: New emissions sources or
modifications to existing emissions sources
that do not exceed NAAQS emission
levels.
Minors: Publicly owned treatment works
with flows less than 1 rnillion gallons per
day. (See: majors.)
Miscellaneous ACM: Interior asbestos-
containing building material or structural
components, members or fixtures, such as
floor and ceiling tiles; does not include-
surfacing materials or thermal system
insulation.
Miscellaneous Materials: Interior build-
ing materials on structural components,
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 leaking.
Mist: Liquid particles measuring 40 to 500
micrometers (pm), are formed by
condensation of vapor. By comparison,
fog particles are smaller than 40 microme-
ters (pm).
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 action.
Mixed Glass: Recovered container glass
not sorted into categories (e.g., color,
.grade). ..•'-.
Mixed Liquor: A mixture of activated
sludge anil water containing organic •
matter undergoing activated sludge treat-
ment in an aeration tank.
Mixed Metals: Recovered metals hot
sorted into categories such as aluminum,
tin, or steel cans or ferrous or non-ferrous
metals.
Mixed Municipal Waste: Solid waste that
has riot been sorted into specific categories
-..' such as plastic, glass, yard trimmings, etc.)
Mixed Paper: Recovered paper not sorted
into categories such as old magazines, old
newspapers, old corrugated boxes, etc.
Mixed Plastic: Recovered plastic unsorted
by category
Mobile Incinerator Systems: Hazardous
waste incinerators that can be transported
from one site to another. ,
Mobile Source: Any non-stationary source
of air pollution such, as cars, trucks,
motorcycles, buses, airplanes, and loco-
motives. , ' ,
Model Plant: A hypothetical plant design
used for developing economic, environ-
mental, and energy impact analyses as.
support for regulations or .regulatory
guidelines; first step in exploring the
economic impact of a potential NSPS.
Modified Bin Method: Way of calculating
the required heating or cooling for a
building based on determining how much
energy the system would use if outdoor
temperatures were within- a certain
temperature interval and then multiply-
ing the energy use by the time the
temperature interval typically occurs.
Modified Source: The enlargement of a
major stationary pollutant sources is often
referred to as modification, implying that
more emissions will occur.
Moisture Content: l.The amount of water
lost from soil upon drying to a constant
weight, expressed 'as the weight per unit
of dry soil or as the volume of water per
unit bulk volume of the soil. For a fully
saturated medium, moisture content
indicates the porosity. 2. Water equivalent
of snow on the ground; an indicator of
snowmelt flood potential.
Molecule: The smallest division of a
compound that still retains or exhibits all
the properties of the substance.
Molten Salt Reactor: A thermal treatment
.unit that rapidly heats waste in a heat-
conducting fluid bath of carbonate salt:
Monitoring: Periodic or continuous sur-
veillance or testing to determine the level
of compliance with statutory require-
ments 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 measure ground-
water levels. 2. A well drilled at a
hazardous waste management facility or
Superfurid site to collect ground-water
samples for the purpose of physical,
chemical, or biological analysis to deter-
mine the amounts, types, and distribution
of. contaminants in the groundwater
beneath the site.
Monoclonal Antibodies (Also called
MABs and MCAs): -1. Man-made
(anthropogenic) clones of a molecule,
produced in quantity for medical or
research purposes. 2.. Molecules, of living
organisms that selectively find and attach
to other molecules to which their structure
conforms exactly. This could also apply to
equivalent 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).
Montreal Protocol: Treaty, signed in 1987,
governs stratospheric ozone • protection
and research, and the production and use
of ozone-depleting substances. It provides
for the end of production of ozone-
depleting substances such as CFCS. Under
:the Protocol, various research groups
continue to assess the ozone layer. The
Multilateral Fund provides'resources to
developing nations to promote .the transi-
' tion to ozone-safe technologies.
Moratorium: During the negotiation
process/a period of 60 to 90 days during
which EPA and potentially responsible,
29
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parties may reach settlement but no site
response activities can be conducted.
Morbidity: Rate of'disease incidence.
Mortality: Death rate.
Most Probable Number: An estimate of
microbial density per uit volume of water
Sample, based on probability theory.
Muck Soils: Earth made from decaying
plant materials.
Mudballs: Round material that forms in
filters and gradually increases in size
when not removed by backwashing.
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.
Multi-Media Approach: Joint approach to
several environmental media, such as air,
water, and land.
Multiple Chemical Sensitivity: A diag-
nostic label for people who suffer multi-
system illnesses as a result of contact with,
or proximity to, a variety of airborne
agents and other substances.
Multiple Use: Use of land for more than
one purpose; e.g., grazing of livestock,
watershed and wildlife protection, recre-
ation, and timber production. Also
applies to use of bodies of water for
recreational purposes, fishing, and water
supply.
Multistage Remote Sensing: A strategy
for landscape characterization that in-
volves gathering and analyzing informa-
tion 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 efflu-
ent from waste water treatment plants
which receive waste water from house-
holds, commercial establishments, and
industries in the coastal drainage basin.
Combined sewer/separate storm over-
flows are included in this category.
Municipal Sewage: Wastes (mostly liq-
uid) orginating from a community; may
be composed of domestic wastewaters
and/or industrial discharges.
Municipal Sludge: Semi-liquid residue
remaining from the treatment of munici-
pal water and wastewater.
Municipal Solid Waste: Common gar-
bage or trash generated by industries,
businesses, institutions, and homes.
Mutagen/Mutagenicity: 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 changes.
N
National Ambient Air Quality Standards
(NAAQS): Standards established by EPA
that apply for outdoor air throughout the
country. (See: criteria pollutants, state
implementation plans, emissions trad-
ing.)
National Emissions Standards for Haz-
ardous Air Pollutants (NESHAPS): Emis-
sions standards set by EPA for an air
pollutant not covered by NAAQS that
may cause an increase in fatalities or in
serious, irreversible, or incapacitating
illness. Primary standards are designed to
protect human health, secondary stan-
dards to protect public welfare-(e.g.,
building facades, visibility, crops, and
domestic animals).
National Environmental Performance
Partnership Agreements: System that
allows states to assume greater responsi-
bility for environmental programs based
on their relative ability to execute them.
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 integrity, as well
as controlling point and nonpoint pollu-
tion sources.
National Municipal Plan: A policy
created in 1984 by EPA and the states in
1984 to bring all publicly owned treatment
works (POTWs) into compliance with
Clean Water Act requirements.
National Oil and Hazardous Substances
Contingency Plan (NOHSCP/NCP): The
federal regulation that guides determina-
tion of the sites to be corrected under both
the Superfund program and the program
to prevent-or control spills into surface
waters or elsewhere.
National Pollutant Discharge Elimina-
tion System (NPDES): A provision of the
Clean Water Act which prohibits dis-
charge of pollutants into waters of the
United States unless a special permit is
issued by EPA, a state, or, where
delegated, a tribal government on an
Indian reservation.
National Priorities List (NPL): EPA's' list
of the most serious uncontrolled or
abandoned hazardous waste sites identi-
fied 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 NPL at least once a
year. A site must be on the NPL to receive
money from the Trust Fund for remedial
action.
National Response Center: The federal
operations center that receives notifica-
tions of all releases of oil and hazardous
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 Response Team (NRT): Repre-
sentatives of 13 federal agencies that, as a
team, coordinate federal responses to
nationally significant incidents of pollu-
tion—an oil spill, a major chemical
release, or a Superfund response action—
and provide advice and technical assis-
tance to the responding agency(ies) before
and during a response action.
National Secondary Drinking Water
Regulations: Commonly referred to as
NSDWRs.
Navigable Waters: Traditionally, waters
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 identi-
fied 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 supervision. 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 measuring
the amount of the light that is deflected.
Netting: A concept in which all emissions
sources in the same area that owned or
controlled by a single company are treated
as one large source, thereby allowing
flexibility in controlling individual sources
in order to meet a single emissions
standard. (See: bubble)
Neutralization: Decreasing the acidity-or
alkalinity of a substance by adding
alkaline or acidic materials, respectively.
New Source: Any stationary source built
or modified after publication of final or
proposed regulations that prescribe a
given standard of performance.
New Source Performance Standards
(NSPS): Uniform national EPA air emis-
sion and water effluent standards which
limit the amount of pollution allowed
from new sources or .from modified
existing sources.
New Source Review (NSR): A Clean Air
Act requirement that State Implementa-
30
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tion. Plans must include a permit review
that applies to the construction and
operation of new and modified/stationary
sources in nonattainment areas to ensure
attainment of national ambient air quality
standards. .
Nitrate: A compound containing nitrogen
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 Water 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 wa-
ters, sanitary landfills, and garbage
dumps. :
Nitric Oxiide (NO): A gas formed by
'combustion under high temperature and
high pressure in an internal combustion
engine; it is converted by sunlight and
photochemical processes in ambient air to
nitrogen oxide. NO is a precursor of
ground-level ozone pollution, or smog.
Nitrif ication:The process whereby ammo-
nia in wastewater is oxidized to nitrite
and then to nitrate by bacterial or chemical
reactions.
Nitrilotriacetic Acid (NTA): A compound
now replacing phosphates in detergents.
Nitrite: 1. An intermediate in the process
of nitrification. 2. Nitrous-oxide salts used
in food preservation.
Nitrogen Dioxide (NO2): The result of
nitric oxide combining with oxygen in the
atmosphere; major component of photo-
chemical smog., ,
Nitrogen Oxide (NOx): The result of
photochemical reactions of nitric oxide in
ambient air; major component of photo-
chemical smog. Product of combustion
from transportation and stationary sources
and a major contributor to the formation
of ozone in the troposphere and to acid
deposition.
Nitrogenous Wastes: Animal or vegetable
residues that contain significant amounts
of nitrogen.,
Nitrophenols: Synthetic organopesticides
containing carbon, hydrpgen, nitrogen,
and oxygen.
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.
No Observable Adverse. Effect Level
(NOAEL): An exposure level at which
thee are no statistically or biologically
significant increases in the frequency or
severity of adverse effects between the
exposed population and its appropriate
control; some effects may be produced at
this level, but they are not considered as
adverse, or as precurors to adverse effects.
In an experiment with several NOAELs,
the regulatory focus is primarily on the
highest one, leading to the common usage
of th4e term 'NOAEL as the highest
exposure without adverse effective. >
No Tilt Planting crops without prior
seedbed preparation, into 'an existing
cover crop, sod, or crop residues, and
eliminating subsequent tillage operations.
No-Observed-Effect-Level (NOEL): Ex-
posure level at which there are no
statistically or biological significant differ-
ences in the frequency or severity of any
effect in the exposed or control popula-
tions.
Noble Metal: Chemically inactive metal
such as gold; does not corrode easily.
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-Aqueous Phase Liquid (NAPL):
Contaminants that remain undiluted as
the original bulk liquid in the subsurface,
e.g., spilled oil. (See: fee product.)
Non-Attainment Area: Area that does not
meet one or more of the National Ambient
Air Quality Standards for the criteria
pollutants designated in the CleanAir Act.
Non"Binding Allocations of Responsi-
bility (NEAR): A process for EPA to
propose a way for potentially responsible
parties to allocate costs among them-
selves.
Non-Community Water System: A pub lie
water system that is, hot a community
water system; e.g., the water supply at a
camp site or national park.
Non-Compliance Coal: Any coal that
emits greater 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 material,
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 poli-
cy which disallows any lowering of
naturally occurring'quality regardless of
preestablished health standards.
Non-Ferrous Metals: Nonmagnetic met-
als-such as aluminum, lead, and copper.
Products made all or in part from such
metals 'include containers ,packaging,
appliances, furniture, electronic equip-
ment, and aluminum foil.
Non-ionizing Electromagnetic Radia-
tion: I. Radiation that does not change the
structure of atoms but does heat tissue and
may cause harmful biological effects. 2.
Microwaves> radio .waves, and low-
frequency electromagnetic fields from
high-voltage transmission lines.
Non-Methane Hydrocarbon (NMHC):
The sum of all hydrocarbon air pollutants
except methane; significant precursors to
ozone formation: , ,
Non-Methane Organic Gases (NMOG):
The sum of all organic air pollutants.
Excluding methane; they account for
aldehydes, ketones, alcohols, and other
pollutants that are not hydrocarbons but
are precursors of ozone.
Non-Point Sources: Diffuse pollution
.sources (i.e., without a single point of
origin or not introduced into a receiving
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 contains
pollutants, contaminants, minerals, or
infective agents.
Non-Road Emissions: Pollutants emitted
by combustion engines on 'farm and
construction equipment, gasoline-pow-
ered lawn and garden equipment, and
powerboats 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. •
Nondischarging Treatment Plant: A treat-
ment plant that does not discharge treated
wastewater into any stream or river. Most
are pond systems that dispose of the total
flow they receive by means of evaporation
or percolation to groundwater, or facilities
that dispose of their effluent by recycling
or reuse (e.g.,"'spray irrigation or ground-
water discharge).
. Nonf riable 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.
Nonhazardous Industrial Waste: Indus-
trial process waste in wastewater not
considered municipal solid waste or
hazardous waste under RARA.
Notice of Deficiency: An EPArequest to a
facility owner or operator requesting
additional information before a prelimi-
nary decision on a permit application can
be made. '
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Notice of Intent to Cancel: Notification
sent to registrants when EPA decides to
cancel registration of a product containing
a pesticide.
Notice of Intent to Deny: Notification by
EPA of its preliminary intent to deny a
permit application.
Notice of Intent to Suspend: Notification
sent to a pesticide registrant when EPA
decides to suspend product sale and
distribution because of failure to submit
requested data in a timely and/or
acceptable manner; or because of immi-
nent hazard. (See: emergency suspen-
sion.)
Nuclear Reactors and Support Facilities:
Uranium mills, commercial power re-
actors, fuel reprocessing plants, and
uranium enrichment facilities.
Nuclear Winten 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 affect world agricultural and
weather patterns.
Nuclide: An atom characterized by the
number of protons, neturons, and energy
in the nucleus.
Nutrient: Any substance assimilated by
living things that promotes growth. The
term is generally applied to nitrogen 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.
o
Ocean Discharge Waiver: Avariance from
Clean Water Act requirements for dis-
charges into marine waters.
Odor Threshold: The minimum odor of a
water or air sample that can just be
detected after successive dilutions with
odorless water. Also called threshold odor.
OECD Guidelines: Testing guidelines
prepared by the Organization of Eco-
nomic and Cooperative Development of
the United Nations. They assist in
preparation of protocols for studies of
toxicology, environmental fate, etc.
Off-Site Facility: A hazardous waste
treatment, storage or disposal area that is
located away from the generating site.
Office Papon High grade papers such as
copier paper, computer printout, and
stationary almost entirely made of un-
coated chemical pulp, although some
ground wood is used. Such waste is also
generated in homes, schools, and else-
where.
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 trad-
ing, netting)
Offstream .Use: Water withdrawn from
surface or groundwater sources for use at
another place.
Oil and Gas Waste: Gas and oil drilling
muds, oil production brines, and other
waste associated with exploration for,
development and production of crude oil
or natural gas.
Oil Desulfurization: Widely used pre-
combustion method for reducing sulfur
dioxide emissions from oil-burning power
plants. The oil is treated with hydrogen,
which removes some of the sulfur by
forming hydrogen sulfide gas.
Oil Fingerprinting: A method that identi-
fies 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 con-
tainment, and/or adsorption. Spills from
tanks and pipelines can also occur away
from water bodies, contaminating the soil,
getting into sewer systems and. threat-
ening underground water sources.
Oligotrophic Lakes: Deep clear lakes
with few nutrients, little organic matter
and a high dissolved-oxygen level.
On-Scene Coordinator (OSC): The pre-
designated EPA, Coast Guard, or Depart-
ment of Defense official who coordinates
and directs Superfund removal actions or
Clean Water Act oil- or hazardous-spill
response actions.
On-Site Facility: A hazardous waste
treatment, storage or disposal area that is
located on the generating site.
Onboard Controls: Devices placed on
vehicles to capture gasoline vapor during
refueling and route it to the engines when
the vehicle is starting so that it can be
efficiently burned.
Onconogenicity: The capacity to induce
cancer.
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
DNAcan start an irreversible series events
leading to a tumor.
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. Opacity is an
indicator of changes in performance of
particulate control systems.
Open Burning: Uncontrolled fires in an
open dump.
Open Dump: An uncovered site used for
disposal of waste without environmental
controls. (See: dump.)
Operable Unit: Term for each of a number
of separate activities undertaken 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 speci-
fied 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 conditions needed to
meet specified performance standards.
Operation and Maintenance: 1. Activities
conducted after a Superfund site action is
completed to ensure that the action is
effective. 2. Actions taken after construc-
tion to ensure that facilities constructed to
treat waste water will be properly
operated and maintained to achieve
normative efficiency levels and prescribed
effluent limitations in an optimum man-
ner. 3. On-going asbestos management
plan in a school or other public building,
including regular inspections, various
methods of maintaining asbestos in place,
and removal when necessary.
Operator Certification: Certification of
operators of community and nontransient
noncommunity water systems, asbestos
specialists, pesticide applicators, hazard-
ous waste transporter, and other such
specialists as required by the EPA or a state
agency implementing an EPA-approved
environmental regulatory program. .
Optimal Corrosion Control Treatment:
An erosion control treatment that minimi-
zes the lead and copper concentrations at
users' taps while also ensuring that the
treatment does not cause the water system
to violate any national primary drinking
water regulations.
Oral Toxicity: 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 Chemicals/Compounds: Natu-
rally occuring (animal or plant-produced
or synthetic) substances containing mainly
carbon, hydrogen, nitrogen, and oxygen.
Organic Matter: Carbonaceous waste
contained in plant or animal matter and
originating from domestic or industrial
sources.
Organism: Any form of animal or plant
life.
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Organophosphates: Pesticides that con-
tain phosphorus; short-lived, but some
can be toxic when first applied.
Organophyllic: A substance that easily
combines with organic compounds.
Organotins: Chemical compounds used
in anti-foulant paints to protect the hulls
of boats and ships, buoys, and pilings
_fr6m marine organisms such as barnacles.
Original AHERA Inspection/Original
Inspection/Inspection: Examination of
school buildings arranged by Local
Education Agencies to identify asbestos-
containing-materials, evaluate their con--
dition, and take samples of materials
suspected to contain asbestos; performed
by EPA-accredited inspectors.
Original Generation Point: Where regu-
lated 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 solvent
(water) but not the dissolved solids.
Other Ferrous Metals: Recyclable metals
from strapping, furniture, and metal
found in tires and consumer electronics
but does not include metals' found in
construction materials or cars, -locomo-
tives, and ships. (See: ferrous metals.)
Other Glass: Recyclable glass from
furniture, appliances, and consumer elec-
tronics. Does not include 'glass from
transportation .products (cars trucks or
shipping containers) and construction or
demolition debris. (See: glass.)
Other Nonferrous Metals: Recyclable
nonferrous metals such as lead, copper,
and zinc from 'appliances, 'consumer
electronics, and nonpackaging aluminum
products. Does not include nonferrous
metals from industrial applications and
construction and demolition debris. (See:
nonferrous metals.) ,
Other Paper: For Recyclable paper from
books, third-class mail, commercial print-
ing, paper towels, plates and cups; and
other nonpackaging paper such as post-
ers, photographic .papers, cards and
games, milk cartons; folding boxes, bags,
wrapping paper, and paperboard. Does
not include wrapping paper or shipping
cartons., • •.
Other Plastics: Recyclable plastic from.' '
appliances, eating utensils, plates, con-
tainers, toys, and various kinds of
equipment. Does not include heavy-duty
plastics such as yielding materials.
Other Solid Waste: Recyclable nonhaz-
ardous solid wastes, other than municipal'
solid waste, covered under Subtitle D of
RARA. (See: solid waste.)
Other Wood: Recyclable wood from
furniture, consumer electronics cabinets,
and other nonpackaging wood products.
Does not include lumber and tree stumps
recovered from construction and demoli-
tion activities, and industrial process
waste such as shavings and sawdust.
Outdoor Air Supply: Air brought into a
building from outside.
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 "mining" of the
groundwater in the basin. (See: ground-
water 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 surface.
As the water flows over the surface,
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: Acollective term for some of the-
primary constituents of photochemical
smog.
Oxidation: The chemical addition of
oxygen to break down pollutants or
organizac waste; e.g., destruction of.
chemicals such as cyanides, phenols, and
organic sulfur compounds in sewage by
bacterial and chemical means.
Oxidation Pond: A man-made (anthropo-
genic) body of water in which waste is
consumed by bacteria, used most fre-
quently with other waste-treatment pro-
cesses; a sewage lagoon.
Oxidation-Reduction Potential: The elec-
tric potential required to transfer electrons
from one compound or element (the '
oxidant) to another compound ^the
reductant); used as a qualitative 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 solvent
containing'oxygen as part. of the mo-
lecular structure. Alcohols and ketones are
oxygenated compounds often used as
paint solvents. ' •
Ozonation/Ozonator: Application of
ozone to water for disinfection or for taste
and odor control. The ozonator is the
device that does this.
1 Ozone (O3): 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 provides 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 widespread of all the criteria
pollutants for which the Clean Air Act
required EPA to set standards. Ozone in
the troposphere is produced through
complex chemical reactions of nitrogen
oxides, which are among the primary
pollutants emitted by combustion sources;
hydrocarbons, released into the atmo-
sphere through the combustion, handling
and processing of petroleum products;
and sunlight.
Ozone Depletion: Destruction of the
stratospheric 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 bromine containing com-
pounds (chlorofluorocarbons or halons),
which break down when they reach the
stratosphere and then catalytically de-
stroy ozone molecules.
Ozone Hole: A thinning break, in the
stratospheric ozone layer. Designation of
amount of such depletion as an "ozone
hole" is made when the detected amount
of depletion exceeds fifty percent. Sea-
sonal ozone holes have been observed
over both the Antarctic and Arctic regions,
part of Canada, and the extreme northeast-
ern United States.
Ozone Layer: The protective layer-in the
atmosphere,, about 15 miles above the
ground, that absorbs some of the sun's1
'ultraviolet rays, thereby reducing the
amount of potentially harmful radiation
that reaches the earth's surface.
33
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JL
Packaging: The assembly of one or more
containers and any other components
necessary to ensure minimum compliance
with a program's storage and shipment
packaging requirements.Also, the contain-
ers/ 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 chemically react with
the liquid.
Packer: An inflatable gland, or balloon,
used to create a temporary seal in a
borehole, probe hole, well, or drive casing.
It is made of rubber or non-reactive
materials.
Palatable Water: Water, at a desirable
temperature, that is free from objection-
able tastes, odors, colors, and turbidity.
Pandemic A widespread epidemic
throughout an area, nation or the world.
Papen In the recycling business, refers to
products and materials, including news-
papers, magazines, pffice papers, corru-
gated containers, bags and some paper-
board packaging that can be recycled into
new paper products.
Paper Processor/Plastics Processor: Inter-
mediate facility where recovered paper or
plastic products and materials are sorted,
decontaminated, and prepared for final
recycling.
Parameter. A variable, measurable
property whose value is a determinant of
the 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. Causes lung damage if smoke
from the crop is inhaled.
Parshall Flume: Device used to measure
the flow of water in an open channel.
Part A Permit, Part B Permit: (See: Interim
Permit Status.)
Participation Rate: Portion of population
participating in a recycling program.
Particle Count: Results of a microscopic
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 water.
Particulates: 1. Fine liquid or solid
particles such as dust,~smoke, mist, fumes,
or smog, found in air or emissions. 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 flocculatiori.
Partition Coefficient: Measure of the
sorption phenomenon, whereby a pesti-
cide is divided between the soil and water
phase; also referred to as adsorption
partition coefficient.
Parts Per Billion (ppb)/Parts Per Million
(ppm): Units commonly used to express
contamination ratios, as in establishing
the maximum permissible amount of a
contaminant in water, land, or air.
Passive Smoking/Secondhand Smoke:
Inhalation of others' tobacco smoke.
Passive Treatment Walls: Technology in
which a chemical reaction takes place
when contaminated ground water comes
in contact with a barrier such as limestone
or a wall containing iron filings.
Pathogens: Microorganisms (.g., bacteria,
viruses, or parasites) that can cause
disease in humans, animals and plants.
Pathway: The physical course a chemical
or pollutant takes from its source to the
exposed organism.
Pay-As-You-Throw/Unit-Based Pricing:
Systems under which residents pay for
municipal waste management and dis-
posal services by weight or volume
collected, not a fixed fee.
Peak Electricity Demand: The maximum
electricity used to meet the cooling load of
a building or buildings in a given area.
Peak Levels: Levels of airborne pollutant
contaminants much higher than average
or occurring for short periods of time in
response to sudden releases.
Percent Saturation: The amount of a
substance that is dissolved in a solution
compared to the amount that could be
dissolved in it.
Perched Watec Zone of unpressurized
water held above the water table by
impermeable rock or sediment.
Percolating Waten 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 Bond: Cash or securities
deposited before a landfill operating
permit is issued, which are held to ensure
that all requirements for operating ad
subsequently closing the landfill are
faithful performed. The money is returned
to the owner after proper closure of the
landfill is completed. If contamination or
other problems appear at any time during
operation, or upon closure, and are not
addressed, the owner must forfeit all or
part of the bond which is then used to
cover clean-up costs.
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 incinerator meets perfor-
mance standards under operating condi-
tions specified in the RCRA permit. (See:
trial burn; performance standards.)
Performance Standards: 1. Regulatory
requirements limiting the concentrations
of designated organic compounds, par-
ticulate-matter, and hydrogen chloride in
emissions from incinerators. 2. Operating
standards established by EPA for various
permitted pollution control' systems,.
asbestos inspections, and various pro-
gram operations and maintenance re-
quirements.
Periphytoru Microscopic underwater
plants and .animals that are firmly
attached to solid surfaces such as rocks,
logs, and pilings.
. Permeability: The rate at which liquids
pass through soil or other materials in a
specified direction.
Permissible Dose: The dose of a chemical
that may be received by an individual.
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 envi-
ronmental regulation; e.g., a permit 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 environment, once
introduced. A compound may persist for
less than a second or indefinitely.
Persistent Pesticides: Pesticides that do
not break down chemically or break
down very slowly and remain in the
environment after a growing season.
Personal Air Samples: Air samples taken
with a pump that is 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).
Personal Measurement: A measurement
collected from an individual's immediate
environment.
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Personal Protective Equipment: Clothing
and equipment worn by pesticide mixers,
loaders and applicators and re-entry
workers, hazmat emergency responders,
workers cleaning up Superfund sites, et al,
which is worn to reduce their exposure to
potentially hazardous chemicals and
other pollutants.
Pest: An insect, rodent, nematode, fungus, !
weed or other form of terrestrial or aquatic
plant or animal life that is injurious to
health or the environment.
Pest Control Operator: Person or com-
pany that applies pesticides as a business
(e.g., exterminator); usually, describes
household services, 'not agricultural ap-
plications. " .
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 desic-
cant. • '
Pesticide Regulation Notice: Formal
notice to pesticide registrants about
important changes in regulatory policy,
procedures, regulations.
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 harmful to
consumers.
PETE (Polyethylene Terepthalate): Ther-
moplastic -material used in plastic soft
drink and rigid containers:
Petroleum: Crude oil or any fraction
thereof that is liquid under normal
conditions.of temperature and pressure.
The term includes petroleum-based sub-
stances comprising a complex blend of
hydrocarbons derived from crude oil
through the process of separation, conver-
sion, upgrading, and finishing, such as
motor fuel, jet oil, lubricants, petroleum
solvents, arid used oil.
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.
Pharmacokinetics: The study of the way
that drugs move through the body after
they are swallowed or injected.
Phenolphthalein Alkalinity: The alkalin-
ity in a water sample measured by the
amount of standard acid needed to lower
thge pH to a level of 8.3 as indicated 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 manufac-
turing. Low concentrations cause taste
and odor problems in water; higher
concentrations can kill aquatic life and
.humans.
Phosphates: Certain chemical compounds
containing phosphorus.
Phosphogypsum Piles (Stacks): Principal
byproduct generated in production of
phosphoric acid from phosphate rock.
These piles may generate radioactive
radon gas.
Phosphorus: An essential chemical food
element that can contribute to' the
eutrophication of lakes and other water
bodies. Increased phosphorus levels re-
sult from discharge of phosphorus-
containing materials into surface waters.
Phosphorus Plants: Facilities using elec-
tric furnaces to produce elemental phos-
phorous for commercial use, such as high
grade phosphoric acid, phosphate-based
detergent, and organic chemicals use.
Photochemical Oxidants: Air pollutants
formed by the action of sunlight on oxides
of nitrogen and hydrocarbons.
Photochemical Smog: Air pollution caused
by chemical reactions of various pollut-
ants emitted from different sources. (See:
photochemical oxidants.)
Photosynthesis: The manufacture by
plants of carbohydrates and oxygen from
carbon dioxide mediated by chlorophyll
in the presence of sunlight. ,
Physical and Chemical Treatment: Pro-
cesses generally used in large-scale
wastewater treatment facilities. Physical
processes may include air-stripping or
filtration. Chemical treatment includes
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.'
Phytoremediation: Low-cost remediation
option for sites with widely • dispersed
contamination at low concentrations.
Phytoremediation: Low-cost remediation
option for sites with widely dispersed
contamination at low concentrations.
Phytotoxic: Harmful to plants. .
Phytotreatment: The cultivation of spe-
cialized plants that absorb specific con-
taminants from the soil through their roots
or foliage. This, reduces the concentration
of contaminants in the soil, but incorpo-
rates them into biomasses that may be
released back into the environment when
the plant dies or is harvested.,
Picocuries Per "Liter pCi/L): A unit of
measure for levels of radon gas; becquerels
per cubic meter is-metric equivalent.
Piezometer: A nonpumping well, gener-
ally of small diameter, for measuring the
elevation of a water table.-
Pilot Tests: Testing a cleanup technology
.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 temperatures;
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
plas'mids carry information that renders
the bacteria resistant to antibiotics.
Plasmids are • often used in genetic '
engineering to carry desired genes into
organisms.
Plastics:Non-metallic chemoreactive com-
pounds molded into rigid or pliable
construction materials, fabrics, etc.
Plate Tower Scrubber: An air pollution
control device that neutralizes hydrogen
chloride gas by bubbling alkaline water
through hole's in a series of metal plates.
Plug Flow: Type of flow tht occurs in
tanks, basins, or eeactors when a slug of
water 'moves through without ever
dispersing or mixing with the rest of the
• water flowing trough.
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 L A visible or measurable
discharge of a contaminant from a giyen
point of origin. Can be visible or thermal
in water, or visible in the air as, for
example, a plume of smoke. 2 The area of
, radiation leaking from a damaged 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/PM-2.5: PM 10 is measure of
particles in the atmosphere with a
diameter of less than ten or equal to a
nominal 10 micrometers. PM-2.5 is a
measure of smaller, particles in the air. PM-
10 has been the pollutant particulate level
standard against which EPA has been
measuring Clean Air Act compliance. Oh
the basis of newer sceiehtific findings, the
Agency is considering -regulations that
will make PM-2.5 the new "standard".
Pneumoconiosis: Health conditions char-
acterized by permanent deposition of
'35
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substantial amounts of particulate matter
in the lungs and by the tissue reaction to
its presence; can range from relatively
harmless forms of sclerosis to the
destructive fibrotic effect of silicosis.
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.
Point-of-Contact Measurement of Expo-
sure: Estimating exposure by measuring
concentrations over time (while the
exposure is taking place) at or near the
place where it is occurring.
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 treat-
ment device applied to the drinking 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
Pollen: The fertilizing element of flower-
ing plants; background air pollutant.
Pollutant: Generally, any substance intro-
duced into the environment that ad-
versely affects the usefulness of a resource
or the health of humans, animals, or
ecosystems..
Pollutant Pathways: Avenues for distri-
bution of pollutants. In most buildings, for
example, HVAC systems are the primary
pathways although all building compo-
nents can interact to affect how air
movement distributes pollutants.
Pollutant Standard Index (PSI): Indica-
tor of one or more pollutants that may be
used to inform the public about the
potential for adverse health effects from
air pollution in major cities.
Pollution: Generally, the presence of a
substance in the environment that because
of its chemical composition or quantity
prevents the functioning of natural
processes and produces undesirable envi-
ronmental and health effects. Under the
Clean Water Act, for example, the term has
been defined as the man-made or man-
induced alteration of the physical, biologi-
cal, chemical, and radiological integrity of
water and other media.
Pollution Prevention: 1. Identifying ar-
eas, processes, and activities which create
excessive waste products or pollutants in
order to reduce or prevent them through,
alteration, or eliminating a process. Such
activities, consistent with the Pollution
Prevention Act of 1990, are conducted
36 .
across all EPA programs and can involve
cooperative -efforts with such agencies as
the Departments of Agriculture and
Energy. 2. EPA has initiated a number of
voluntary programs in which industrial,
or commercial or "partners" join with EPA
in promoting activities that conserve
energy, conserve and protect water
supply, reduce emissions or find ways of
utilizing them as energy resources, and
reduce the waste stream. Among these are:
Agstar, to reduce methane emissions
through manure management. Climate
Wise, to lower industrial greenhouse-gas
emissions and energy costs. Coalbed
Methane Outreach, to boost methane
recovery at coal mines. Design for the
Environment, to foster including environ-
mental considerations in product design
and processes.
Energy Star programs, to promote energy
efficiency irt commercial and residential
buildings, office equipment, transform-
ers, , computers, office equipment, and
home appliances. Environmental Ac-
counting, to help businesses identify
environmental costs and factor them into
management'decision making.
Green Chemistry, to promote and recog-
nize cost-effective breakthroughs in chem-
istry that prevent pollution. Green Lights,
to spread the use of energy-efficient
lighting technologies. Indoor Environ-
ments, to reduce risks from indoor-air
pollution. Landfill Methane Outreach, to
develop landfill gas-to-energy projects.
Natural Gas Star, to reduce methane
emissions from the natural gas industry.
Ruminant Livestock Methane, to reduce
methane emissions from ruminant live-
stock. Transportation Partners, to reduce
carbon dioxide emissions from the trans-
portation sector.
Voluntary Aluminum Industrial Partner-
ship, to reduce perfluorocarbon emissions
from the primary aluminum industry.
WAVE, to promote efficient water use in
the lodging industry.
Wastewi$e, to reduce business-generated
solid waste through prevention, reuse,
and recycling. (See: Common Sense
Initiative and Project XL.)
Portal-of-Entry Effect A local effect
produced in the tissue or organ of first
contact between a toxicant and the
biological system.
Polonium: A radioactive element that
occurs in pitchblende and other uranium-
containing ores.
Polyelectrolytes: Synthetic chemicals that
help solids to clump during sewage
treatment.
Polymer: A natural or synthetic chemical
structure where two or more like mol-
ecules are joined to form a more complex
molecular structure (e.g., polyethylene 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 Risk: A population sub-
group that is more likely to be exposed to
a chemical, or is more sensitive to the
chemical, than is the general population.
Porosity: Degree to which soil, gravel,
sediment, or rock is permeated with pores
or cavities through which water or air can
move.
Post-Chlormation: Addition of chlorine
to plant effluent for disinfectant purposes
after the effluent has been treated..
Post-Closure: The time period following
the shutdown of a waste management or
manufacturing facility; for monitoring
purposes, often considered to be 30 years.
Post-Consumer Materials/Waste: Recov-
ered materials that are diverted from
municipal solid waste for the purpose of
collection, recycling, and disposition.
Post-Consumer Recycling: Use of materi-
als generated from residential and con-
sumer waste for new or similar purposes;
e.g. converting wastepaper from offices
into corrugated boxes or newsprint.
Potable Water: Wafer that is safe for
drinking and cooking.
Potential Dose: The amount of a com-
pound contained in material swallowed,
breathed, or applied to the skin.
Potentially Responsible Party (PRP):
Any individual or company—including
owners, operators, transporters or genera-
tors—potentially responsible for, or con-
tributing to a spill or other contamination
at a Superfund site. Whenever possible,
through administrative and legal actions,
EPA requires PRPs to clean up hazardous
sites they have contaminated.
Potentiation: The ability of one chemical
to increase the effect of another chemical.
Potentiometric Surface: The surface to
which water in an aquifer can rise by
hydrostatic pressure.
Precautionary Principle: When informa-
tion about potential risks is incomplete,
basing decisions about the best ways to
manage or reduce risks on a preference for
avoiding unnecessary health risks instead •
of on unnecessary economic expendi-
tures.
Pre-Consumer Materials/Waste: Materi-
als generated in manufacturing and
converting processes such as manufactur-
ing scrap and trimmings and cuttings.
Includes print overruns, overissue publi-
cations, and obsolete inventories.
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Pre-Harvest Interval: THe time between
the last pesticide application and harvest
of the treated crops. '. •
Prechlorination: The addition of chlorine
at the headworks of a treatment plant
prior to other treatment processes. Done
mainly , for disinfection and control of
tastes, odors, and aquatic growths, and to
aid in coagulation and settling,
Precipitate: A substance separated from a
solution or suspension by chemical or
physical change.
Precipitation: Removal of hazardous
solids from liquid waste to permit safe
disposal; removal of particles .from
airborne emissions as in rain (e.g., acid
precipitation).
Precipitatdr: Pollution control device that
collects particles from an air stream.
Precursor: In photochemistry, a com-
pound antecedent to a pollutant. For
example, volatile organic compounds
(VOCs) and nitric oxides of nitrogen react
.in sunlight to form ozone or other
photochemical oxidants. As such, VOCs
and dxides of nitrogen are precursors.
Preliminary Assessment: The process of
collecting and reviewing available
information about a known or suspected
waste site or release.
Prescriptive: Water rights which are
acquired by diverting water and putting it
to use in accordance with specified
procedures; e.g., filing a request with a
state agency to use unused water in a
stream, river, or lake.
Pressed Wood Pro ducts: Materials used in
building and furniture construction that
are made from wood veneers, particles, or
fibers bonded together with an adhesive
under heat and pressure.
Pressure, Total: In flowing air, the sum of
the static and velocity pressures.
Pressure Sewers: A system of pipes in
which water, wastewater, or other liquid is
pumped to a higher elevation.
Pressure; Static: In flowing air, the total
pressure minus velocity pressure, push-
ing equally in all directions.
Pressure, Velocity: In flowing air, the
pressure due to velocity and density of air.
Pretreatment: Processes used to reduce,
eliminate, or alter the nature of wast-
ewater pollutants from non-domestic
sources before they are discharged into
publicly owned treatment works (POT Ws).
Prevalent Level Samples: Air samples
taken under normal conditions (also
known as ambient background samples).
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 primary ,and secondary
ambient air quality standards.
Primacy: Having the primary responsibil-
ity 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 Administrator,'
will not adversely affect human health.
Primary Effect, An effect where the
stressor acts directly on the ecological
component of interest, not on other parts
of the ecosystem. (See: secondary effect.)
Primary Standards: National ambient air
quality standdards designed to protect
human health with an adequate margin
for safety. (See National Ambient Air
Quality Standards, secondary standards)
Primary Waste Treatment: First steps in
wastewater treatment; screens and sedi-
mentation tanks are used to remove most
materials that float or will settle. Primary
treatment removes .about 30 percent of
carbonaceous biochemical oxygen de-
mand from domestic sewage.
Principal? Organic Hazardous Constitu-
ents (PQHCs): 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 watr.
law that allocates the rights to use water
on a first-come, first-served basis.
Probability of Detection: The likelihood, .
expressed as a percentage, that a' test
method will correctly identify a leaking
tank. ' .
Process Variable: A physical or chemical
quantity which is usually measured and
controlled in the operation of a water
treatment plant or industrial plant.
Process Verification: Verifying that pro-
cess raw materials, water usage, waste
treatment processes, production rate and
other facts relative to quantity and quality
'of pollutants Contained in discharges are
substantially described in' the permit
application and the issued permit.
Process Wastewater: Any water that
comes into contact with any raw material,
product, byproduct, or waste.
Process Weight Total weight of all
materials, including fuel, > used in a
manufacturing process; used to calculate
the allowable particulate emission" rate. .
Producers: Plants that perform photosyn-
thesis/and provide food to consumers.
Product Level: The level of a product in a
storage tank. .
Product Water ' Water that has passed
throuigh 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 incinerator (e.g.,
charcoal is a P.I.C. from burning wood).
Project XL: An EPA initiative to give states
and the regulated community the flexibil-
ity to develop comprehensive strategies as
alternatives to multiple current regulatory ,
requirements in order to exceed compli-
ance and increase overall environmental
benefits. ' ''• • '' '
Propellanfc Liquid in a self-pressurized
pesticide product that expels the active
ingredient from its container.,
Proportionate Mortality Ratio (PMR):
The number of deaths from, a specific
cause in a specific period of time per 100
deaths from all causes in the same time
period.
Proposed Plan: A plan for a site cleanup
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 enzymes. '
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 animals -that are
larger and more complex than bacteria.
May cause disease.
Public Comment Period: The time
allowed for the public to express its views
and concerns regarding an action by EPA
(e.g., a, .Federal Register Notice of,
proposed rule-making, a public notice of a
draft permit, or a Notice Of Intent to
Deny).
Public Health Approach: Regulatory and
voluntary focus on effective and feasible
risk management .actions at the national
and community level to reduce human
exposures and risks, with priority given to
reducing exposures: with the biggest
impacts in terms of the number affected
and severity of effect.
Public Health Context: The incidence;
prevalence, and severity of diseases in
communities or populations and the
factors that account for them, including
infections, exposure to pollutants, and
other exposures or activities.
. '.'•"'• 37
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Public Hearing: A formal meeting whe-
rein EPA officials hear the public's views
and concerns about an EPA action or
proposal. EPA is required to consider such
comments when evaluating 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
over radio and television stations. 2. In the
safe drinking water program, water
suppliers are required to publish and
broadcast notices when pollution prob-
lems are discovered.
Public Water System: A system that
provides piped water for human con-
sumption to at least 15 service connections
or regularly serves 25 individuals.
Publicly Owned Treatment Works
(POTWs): Awaste- treatment works owned
by a state, unit of local government, or
Indian tribe, usually designed to treat
domestic wastewaters.
Pump Test: A procedure used for
determining the gas-generation rate of a
landfill; drilling test wells and installing
pressure probes.
Pumping Station: Mechanical device
installed in sewer or water system or other
liquid-carrying pipelines to move the
liquids to a higher level.
Pumping Test: A test conducted to
determine aquifer or well characteristics.
Purging: Removing stagnant air or water
from sampling zone or equipment prior to
sample collection.
Putrefaction: Biological decomposition of
organic matter; associated with anaerobic
conditions.
Putrescible: Able to rot
cause odors and attract
Pyrolysis: Decomposition of a chemical
by extreme heat.
quickly enough tc
flies.
Q
Qualitative Use Assessment Report
summarizing the major uses of a pesticide
including percentage of crop treated, and
amount of pesticide used on a site.
Quality Assurance/Quality Control: A
system of procedures, checks, audits, and
corrective actions to ensure that all EPA
research design and performance, envi-
ronmental monitoring and sampling, and
other technical and reporting activities are
of the highest achievable quality.
38
Quench Tank: A water-filled tank used to
cool incinerator residues or hot materials
during industrial processes.
R
Radiation: Transmission of energy though
space or any medium. Also known as
radiant energy.
Radiation Standards: Regulations that set
maximum exposure limits for protection
of the public from radioactive materials.
Radio Frequency Radiation: (See non-
ionizing electromagnetic radiation.)
Radioactive Decay: Spontaneous change
in an atom by emission of of charged
particles and/or gamma rays; also known
as radioactive disintegration and radioac-
tivity.
Radioactive Substances: Substances that
emit ionizing radiation.
Radioisotopes: Chemical variants of
radioactive elements with potentially
oncogenic, teratogenic, and mutagenic
effects on the human body.
Radionuclide: Radioactive particle, man-
made (anthropogenic) or natural, with a
distinct atomic weight number. Can have
a long life as soil or water pollutant.
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 specified weather
conditions.
Radius of Influence: "1. The radial
distance from the center of a wellbore to
the point where there is no lowering of the
water table or potentiometric surface (the
edge of the cone of depression); 2. the
radial distance from an extraction well
that has adequate air flow for effective
removal of contaminants when a vacuum
is applied to the extraction well.
Radon: A colorless naturally occurring,
radioactive, inert gas formed by radioac-
tive 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 themselves to airborne
dust and other particles and, if inhaled,
danage the linings of the lungs.
Radon Decay Products: A term used to
refer collectively to the immediate prod-
ucts 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.
Rainbow Report Comprehensive docu-
ment giving the status of all pesticides
now or ever in registration or special
reviews. Known as the "rainbow report"
because chapters are printed on different
colors of paper.
Rasp: A machine that grinds waste into a
manageable material and helps prevent
odor.
Raw Agricultural Commodity: An un-
processed human food or animal feed
crop (e.g., raw carrots, apples, corn, or
eggs.)
Raw Sewage: Untreated wastewater and
its contents.
Raw Water: Intake water prior to any
treatment or use.
Re-entry: (In indoor air program) Refers
to air exhausted from a building that is
immediately brought back into the system
through the air intake and other openings.
Reaeration: Introduction of air into the
lower layers of a resrvoir. As the air
bubbles form and rise .through the water,
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 atmosphere.
Real-Time Monitoring: Monitoring and
measuring environmental developments
with technology and communications
systems that provide time-relevant infor-
mation to the public in an esily under-
stood format people can use in day-to-day
decision-making about their health and
the environment.
Reasonable Further Progress: Annual
incremental reductions in air pollutant
emissions as reflected in a State Imple-
mentation Plan~that EPA deems sufficient
to provide for the attainment of the
applicable national ambient air quality
standards by the statutory deadline.
Reasonable Maximum Exposure: The
maximum exposure reasonably expected
to occur in a population.
Reasonable Worst Case: An estimate of
the individual dose, exposure, or risk level
received by an individual in a defined
population that is greater than the 90th
percentile but less than that received by
anyone in the 98th percentile in the same
population.
Reasonably Available Control Measures
(RACM): A broadly defined term refer-
ring to technological and other measures
for pollution control.
Reasonably Available Control Technolo-
gy (RACT): Control technology that is
reasonably available, and both technologi-
cally and economically feasible. Usually
applied to existing sources in nonattain-
ment areas; in most cases is less stringent
than new source performance standards.
Recarbonization: Process in which carbon
dioxide is bubbled into water being
treated to lower the pH.
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Receiving Waters: A river, lake/ ocean,
stream or other watercourse into which
wastewater or treated effluent is dis-
charged.
Receptor: Ecological entity exposed to a
stressor. .
Recharge: The process by which water is
added to a zone of saturation, usually 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 microorganism
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.
-Recommended Maximum Contaminant
Level (RMCL): The maximum level of a
contaminant in drinking water at which
no known or anticipated adverse effect on
human health would occur, and that
includes an adequate margin of safety.
Recommended levels are nonenforceable
health goals. (See: maximum contaminant
• level.) v'
Reconstructed Source: Facility in which
components are replaced to such an extent
that the fixed capital cost of the new •
components exceeds 50 percent of the
capital cost of constructing a comparable
brand-new facility. New-source perfor-
mance standards may be applied to
sources reconstructed-after the proposal
of the standard if it is technologically and
economically feasible to meet the stan-
dards.
Reconstruction of Dose:Estimating expo-
sure after it has occurred by using
evidence within an organism such as
chemical levels in tissue or fluids.
Record of Decision (ROD): A public
document that explains which cleanup
alternative^) 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 municipal
solid waste generated in a specific 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 aluminum
cans, paper, and bottles, etc.).
Recycling and Reuse Business Assis-
tance Centers: Located in state solid-
waste or economic-development agen-
cies, these centers provide recycling
businesses with customized and targeted
assistance.
Recycling Economic Development Ad-
vocates: Individuals hired by state or
tribal economic development offices to
focus financial/ marketing, and permit-
ting resources on creating recycling
businesses. • . '
Recycling Mill: Facility where recovered
materials are .remanufactured into new
products.
Recycling Technical Assistance Partner-
ship National Netwprk: A national
information-sharing resource designed to
help businesses and manufacturers in-
crease their use of recovered materials.
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 and often fatal to fish,
perhaps stimulated by the addition of
nutrients. A tide can be red, green, or
brown, depending on the .coloration of the
plankton.
Redemption Program: Program in which
consumers are monetarily compensated
for the collection of recyclable materials,
generally through prepaid deposits or
taxes on beverage containers. In some
states or localities legislation has enacted
redemption programs to help prevent
roadside litter. (See: bottle bill.)
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 concentration
of a chemical known to cause health
problems; also referred to as the ADI, or
acceptable daily intake. Also defined as an
estimate, (with uncertainty spanning
perhaps an order of magnitude) of the
daily exposure to the human population
(including sensitive subgroups) that is
likely to be without risk of deleterious
effects during a lifetime.'
Reformulated Gasoline: Gasoline with a
different composition from conventional
gasoline (e.g., lower aromatics content)
that cuts air pollutants.
Refueling Emissions.- Emissions released '
during vehicle re-fueling.
Refuse: (See: solid waste.)
Refuse Reclamation: Conversion of solid
, waste into useful products; e.g., compost-
ing organic wastes to make soil condition-
ers or separating aluminum and other
' metals for recycling.
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 coordination
of activities at the request of the On-Scene
Coordinator before and during a signifi-
cant pollution incident such as an oil spill,
major chemical release, or Superfund
response.
Registrant: Any manufacturer or formula-
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 Insecticide,
Fungicide, and Rodenticide Act, EPA is
responsible for registration (pre-market
licensing) of pesticides on the basis of,data
demonstrating no unreasonable adverse
effects on human health .or the environ-
ment when applied according to ap-
proved label directions.
Registration Standards: Published docu-
ments which include summary reviews of
• the data available on a pesticide's active
ingredient, data gaps, and the Agency's
existing regulatory position on the pesti- •
cide. •
Regulated Asbestos-Containing Mate-
rial (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 powder in the
co'urse of demolition or renovation
•operations.
Regulated Medical Waste: Under the
Medical Waste Tracking Act of 1988, any
solid waste generated in the diagnosis,
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 products; human pathological
body wastes from surgery 'and autopsy;
contaminated animal carcasses from medi-
cal research; waste from patients with
communicable diseases; and all used
sharp implements, such as needles and
scalpels, and certain unused sharps. (See:
treated medical waste; untreated medical
waste; destroyed medical waste.)
Relative Ecological Sustainability: Abil-
ity of an ecosystem to maintain relative
ecological integrity indefinitely.
39
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Relative Permeability: The permeability
of a rock to gas, NAIL, or water, when any
two or more are present.
Relative Risk Assessment: Estimatingthe
risks associated with different sfressors or
management actions.
Release: Any spilling, leaking, pumping,
pouring, emitting, emptying, discharg-
ing, injecting, escaping, leaching, dump-
ing, or disposing into the environment of a
hazardous or toxic chemical or extremely
hazardous substance.
Remedial Action (RA): The actual con-
struction or implementation phase of a
Superfund site cleanup that follows
remedial design.
Remedial Design: A phase of remedial
action that follows the remedial investiga-
tion/feasibility study and includes devel-
opment 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; estab-
lish 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 hazardous
substances that is serious but not an
immediate threat to public health.
Remediation: 1. Cleanup or other meth-
ods used to remove or contain a toxic spill
or hazardous materials from a Superfund
site; 2. for the Asbestos Hazard Emer-
gency Response program, abatement
methods including evaluation, 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, aerial
photography, and open path measure-
ments.
Removal Action: Short-term immediate
actions taken to address releases of
hazardous substances that-require expe-
dited response. (See: cleanup.)
Renewable Energy Production Incentive
(REPD: Incentive established by the
Energy Policy Act available to renewable
energy power projects owned by a state or
40
local government or nonprofit electric
cooperative.
Repeat Compliance Period: Any subse-
quent compliance period after the initial
one.
Reportable Quantity (RQ): Quantity of a
hazardous substance that triggers reports
under CERCLA. If a substance exceeds its
RQ, the release must be reported to the
National Response Center, the SERC, and
community 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.
identifical 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 scientific
and regulatory standards. EPA reregisters
pesticides through its Registration Stan-
dards Program.
Reserve Capacity: Extra treatment capac-
ity built into solid waste and wastewater
treatment plants and interceptor sewers to
accommodate flow increases due to future
population growth.
Reservoir Any natural or artificial
holding area used to' store, regulate, or
control water.
Residential Use: Pesticide application in
and around houses, office buildings,
apartment buildings, motels, and other
living or working areas.
Residential Waste: Waste generated in
single and multi-family homes, including
newspapers, clothing, disposable table-
ware, food packaging, cans, bottles, food
scraps, and yard trimmings other than
those that are diverted to backyard
composting. (See: Household hazardous
waste.)
. Residual: Amount-of a pollutant remain-
ing in the environment after a natural or
technological process has taken place; e.g.,
the sludge remaining after initial wast-
ewater treatment, or particulates remain-
ing 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 Achievable
Control Technology (MACT).
Residual Saturation: Saturation level
below which fluid drainage will not occur.
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 environmental
conditions or attacks by chemicals or
disease. May be inborn or acquired.
Resource Recovery: The process of
obtaining matter or energy from materials
formerly discarded.
Response Action: 1. Generic term for
actions taken in response to actual or
potential health-threatening environmen-
tal events such as spills, sudden releases,
and asbestos abatement/management
problems. 2. A CERCLA-authorized ac-
tion 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
removing the sources of ground-water
contamination and halting further migra-
tion of contaminants. 3. Any of the
following actions taken in school build-
ings in response to AHERA to reduce the •
risk of exposure to asbestos: removal,
encapsulation, enclosure, repair, and
operations and maintenance. (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 Entry Interval: The time after a
pesticide application during which entry
into the treated area is restricted.
Restricted Use: A pesticide may be
classified (under FIFRA regulations) for
restricted use if 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:Enzyrries that recog-
nize specific regions of a long DNA
molecule and cut it at those points.
Retrofit: Additioin of a pollution control
device on an existing facility without
making major changes to the generating
plant. Also called backfit.
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 "OP using a coffee
can to hold nuts and bolts.
Reverse Osmosis: A treatment process
used in water systems by adding pressure
to force water through a semi-permeable
membrane. Reverse' osmosis removes
most drinking water contaminants. Also.
used in wastewater treatment. Large-scale
reverse osmosis plants are being devel-
oped.
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Reversible Effect: An effect which is not
permanent; especially adverse effects
which diminish when exposure to a toxic
chemical stops.
Ribonucleic Acid (RN A): A molecule that
carries the genetic message from DNAtq a
cellular protein-producing mechanism.
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 opacity
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 differiing density,
diversity, and productivity of plant and
animal species relative to nearby uplands.
Riparian Rights: Entitlement of a land
owner to certain uses of water on or
bordering the 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 (Adverse) for Endangered Species:
Risk to aquatic species if anticipated
pesticide residue levels equal one-fifth of
LD10 or one-tenth of LG50; risk to
terrestrial species if anticipated pesticide
residue levels equal one-fifth of LC10 or
one-tenth of LC50.
Risk Assessment: Qualitative and quanti-
tative evaluation of the risk posed' to
human health and/or the environment by
the actual or potential presence and /or
use of specific pollutants.
Risk Characterization: The last phase of
the risk assessment process that estimates
the potential for adverse health' or
ecological effects to, occur from exposure
to a stressor and evaluates the uncertainty
involved.
Ris,k Communication: The exchange of
information about health or environmen-
tal risks among risk assessors and
managers, the general public, "hews
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, obes- ity) or variables (e.g.,
Smoking, occupational exposure level)
associated with increased probability of a
toxic effect. ' '
Risk for Non-Endangered Species: Risk
to species if anticipated pesticide residue
levels are equal to or greater than LC50.
Risk Management: The process of evaluat-
ing and selecting alternative regulatory
and non-regulatory responses to risk. The
selection process necessarily requires the
consideration of legal, economic, and
behavioral factors. •> • ,
Risk-based Targeting: The direction of
resources to those, areas that have been
identified as having the highest potential
• or actual adverse effectg'on human health
and/or the environment.
Risk-Specific Dose: The dose associated
with a specified risk level.
River Basin: The land area drained by a
river and its tributaries.
Rpdenticide: A chemical or agent used to
destroy rats or other rodent pests, 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 burning.
Rough Fish: Fish not prized for sport or
eating/such as gar and suckers. Most are,
more tolerant of changing environmental
conditions than are game or foood 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, institutions,
and workplaces.
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 fuel 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 (sacrifice it) to
corrosion while the rest of the water
supply facility remains relatively corro-
sion-free. .
Safe: Condition of exposure under which
there is a practical certrainty that no harm
will result to exposed indiviuals.
Safe Water: Water that does not contain
, harmful bacteria; toxic materials, or
chemicals, and is considered safe for
drinking even if it may have taste, odor,
color/and certain mineral problems.
Safe Yield:. The annual amount of water
that can be taken from a source of supply
over a period of years without depleting
that source beyond its ability to be
replenished naturally in "wet years."
Safener: A chemical added to a pesticide
to keep it from injuring plants.
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 materi-
als.
Sampling Frequency: The interval be-
tween the collection of successive samples.
Sanctions: Actions taken by the federal
government for failure to provide or
implement a State Implementation Plan
(SIP). Such action may include withhold-
ing 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 industrial
waste, not storm water.'
Sanitary.Survey: An on-site review of the
water sources, facilities, equipment, opera-
tion and maintenance of a public water
system to evaluate the adequacy of those
elements for producing and distributing
safe drinking water.
Sanitary Water (Also known as gray
water): Water discharged from sinks,
showers, kitchens, or other nonindustrial
operations, but not from commodes.
Sanitation: Control of physical factors in
the human environment that could harm '
development, health, or survival.
Saprolite: A soft, clay-rich, thoroughly
decomposed rock formed in place by
chemical weathering of igneous or meta-
morphic rock. Forms in humid, tropical,
or subtropical climates.
Saprophytes: Organisms, living on dead
or decaying organic matter that help
natural decomposition of organic matter
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 atmosphere. •
Saturation: The condition''of a liquid
when it has taken into solution the
maximum possible quantity of a given
. • 41
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substance at a given 'temp-erature and
pressure.
Science Advisory Board (SAB): A group
of external scientists who advise EPA on
science and policy.
Scrap: Materials discarded from manufac-
turing operations that may be-suitable for
reprocessing.
Scrap Metal Processor: Intermediate
operating facility where recovered metal
is sorted, cleaned of contaminants, and
prepared for recycling.
Screening: Use of screens to remove
coarse floating and suspended solids from
sewage.
Screening Risk Assessment: A risk
assessment performed with few data and
many assumptions to identify exposures
that should be evaluated more carefully
for potential risk.
Scrubber: An air pollution device that
uses a spray of water or reactant or a dry
process to trap pollutants in emissions.
Secondary Drinking Water Regulations:
Non-enforceable regulations applying to
public water systems and specifying the
maximum contamination levels that, in
the judgment of EPA, are required to
protect the public welfare. These regu-
lations apply to any contaminants that
may adversely affect the odor or ap-
pearance of such water and consequently
may cause people served by the system to
discontinue its use.
Secondary Effect: Action of a stressor on
supporting components of the ecosystem,
which in turn impact the ecological
component of concern. (See: primary
effect.)
Secondary Materials: Materials that have
been manufactured and used at least once
and are to be used again.
Secondary Standards: National ambient
air quality standards designed to protect
welfare, including effects on soils, water,
crops, vegetation, man-made (anthropo-
genic) materials, animals, wildlife,
weather, visibility, and climate; damage to
property; transportation hazards; eco-
nomic values, and personal comfort and
well-being.
Secondary Treatment: The second step in
most publicly owned waste treatment
systems in which bacteria consume the
organic parts of the waste. It is accom-
plished by bringing together waste,
bacteria, and oxygen in trickling filters~or
in the activated sludge process. This
treatment removes floating and settleable
solids and about 90 percent of the oxygen-
demanding substances and suspended
solids. Disinfection is the final stage of
secondary treatment. (See: primary, ter-
tiary treatment.)
Secure Chemical Landfill: (See: landfills.)
Secure Maximum Contaminant Level:
Maximum, permissible level of a contami-
nant in water delivered to the free flowing
outlet of the ultimate user, or of
contamination resulting from corrosion of
piping and plumbing caused by water
quality.
Sediment Yield: The quantity of sediment
' arriving at a specific location.
Sedimentation: Letting solids settle out of "
wastewater by gravity during treatment.
Sedimentation Tanks: Wastewater tanks
in which floating wastes are skimmed off
and settled solids are removed for
disposal.
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 water so that
sunlight cannot reach aquatic plants.
Careless farming, mining; and building
activities will expose sediment materials,
allowing them to wash off the land after
rainfall.'
Seed Protectanfc 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 storage facilities.
Selective Pesticide: A chemical designed
to affect only certain types of pests,
leaving other plants and animals un-
harmed.
Semi-Confined Aquifen An aquifer
partially confined by soil layers of low
permeability through which recharge and
discharge can still occur.
Semivolatile Organic Compounds: Or-
ganic compounds that volatilize slowly at
standard temperature (20 degrees C and 1
atm pressure).
Senescence: The aging process. Some-
times used to describe lakes or other
bodies of water in advanced stages of-
eutrophication. Also used to describe
plants and animals.
Septic System: An on-site system de-
signed to treat and dispose of domestic
sewage. Atypical septic system consists of
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 and
must be pumped out periodically.
Septic Tank An underground storage
tank for wastes from homes not connected
to a sewer line. Waste goes directly from
the home to the tank. (See: septic system.)
Service Connector: The pipe that carries
tap water from a public water main to a
building.
Service Line Sample: A one-liter sample
of water that has been stnding for at least
6 hours in a service pipeline and is
collected according to federal regulations.
Service Pipe: The pipeline extending from
trhe water main to the building served or
to the consumer's system.
Set-Back: Setting a thermometer to a
lower temperature when the building is
unoccupied to reduce consumption of
heating energy. Also refers to setting the
thermometer to a higher temperature
during unoccupied periods in the cooling
season.
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 device.
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 consecutive
days that would be expected to occur once
in ten years.
Sewage The waste and wastewater
produced by residential and commercial
sources and discharged into sewers,
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 carries
wastewater and storm-water runoff from
the source to a treatment plant or receiving
stream. "Sanitary" sewers carry house-
hold, industrial, and commercial waste.
"Storm" sewers carry runoff from rain or
snow. "Combined" sewers handle both.
Sewerage: The entire system of sewage
collection, treatment, and disposal.
Shading Coefficient: The amount of the
sun's heat transmitted through a given
window compared with that of a standard
1/8- inch-thick single pane of glass under
the same conditions.
Sharps: Hypo.dermic 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 laboratories. Also
included are other types .of broken or
unbroken glassware that were in contact
42
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•with, infectious agents, su.cH 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 containing
unusual amounts of algae, colloidal
matter, color, suspended solids, turbidity,
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.
Sick Building Syndrome: Building whose
occupants experience acute health and/or
comfort effects that appear to be linked to
time spent therein, but where no specific
.illness or cause can, be identified.
Complaints may be localized in a
particular room or zone, or may spread
throughout the building. (See: building-
related illness.) ;
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
resulting from a new source in previously
"clean" areas. (See: prevention of signifi-
cant 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 potential to substantially .
affect the quality of receiving waters.
Significant Non-Compliance: (See signifi-
cant violations.)
Significant Potential Source of Contami-
nation: A facility or activity that stores,
uses, or produces compounds with
potential for significant contaminating
impact if released into the source water of
a public water supply.
Significant Violations: Violations by
point source dischargers of sufficient
magnitude or duration to be a regulatory
priority.
Silt: Sedimentary materials composed of
fine or intermediate-sized mineral parti-
cles. .
Silviculture: Management of forest land
for timber.
Single-Breath Canister: Small one-liter
canister designed to capture a single
breath. Used in air pollutant ingestion
research.
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 oŁ the body of water where the
agent and the oil are biodegraded.
SIP Call: EPA action requiring a state to
resubmit all or part of its State Implemen-
tation Plan to demonstrate attainment of
the require national ambient air quality
standards within the statutory deadline. A
SIP Revision is a revision of a SIP altered at
the request of EPA or on a state's initiative.
(See: State Implementation Plan.)
Site: An area 'or place within the
jurisdiction of the EPA and/or a state:
Site Assessment Program: A means of
evaluating hazardous waste sites through
preliminary assessments and site inspec-
tions to develop a Hazard Ranking System
score. '
Site Inspection: The collection of informa-
tion from a Superfund site to determine
the extent and severity of hazards posed
by the site. It follows and is more extensive
than a preliminary assessment. The
purpose is to gather information, neces-
sary to score the site, -using the Hazard
Ranking System, and'to determine if it
presents an immediate threat requiring
prompt removal.
Site Safety Plan: A crucial element in all
removal actions, it includes information
on equipment being used, precautions to
be taken, and steps to take in the eventof
an on-site emergency.
Siting: The p'rocess of choosing a location
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 removal
of chemical and biological contaminants.
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 complex
organic substances like sewage sludges
are biologically dredged. During 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-someti-
mes referred to as "Squeegee"): Persons
or enterprises that produce 220-2200
pounds per month of hazardous waste;
they are required 'to keep more records
than conditionally exempt generators:
The largest category of hazardous waste
generators, SQGs, include automotive
shops, dry cleaners, photographic de-
velopers, and many other small busi-
nesses. (See: conditionally exempt genera-
tors.)
Sinelter: A facility that melts or fuses ore,
often with an accompanying chemical
change, to' separate its metal content.
Emissions cause pollution. "Smelting" is
the process involved. .
Smog: Air pollution typically 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 dissolved
minerals such as salts, of calcium 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 further treatment and
.disposal.
Soil and Water Conservation Practices:
Control measures consisting of manage-
, rial, vegetative, and structural practices to
-reduce the loss of soil and water.
Spil Conditioner: An organic material
like humus or compost that .helps- soil
absorb water, build a bacterial community,.
and take up mineral nutrients;
Soil Erpdibility: An indicator of a soil's
susceptibility to raindrop impact, runoff,
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 under
pressure.
Soil Moisture: The water contained in the
pore space of the unsaturated zone.
Soil Sterilant: 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
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, of the
drinking water of an area.
Solid Waste: Non-liquid, non-soluble
materials ranging from' municipal gar-
bage to industrial wastes that contain
complex and sometimes hazardous sub-
stances. Solid wastes also include sewage
sludge, agricultural refuse/demolition
wastes, and mining residues. Technically,
solid waste also refers to liquids and gases
in containers.
Solid Waste Disposal: The final place-
ment of refuse that is not salvaged or
recycled.
43
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Solid Waste Management Supervised
handling of waste materials from their
source through recovery processes to
disposal.
Solidification and Stabilization: Re-
moval of wastewater from a waste or
changing it chemically to make it less
permeable and susceptible to transport by
water.
Solubility: The amount of mass of a
compound that will dissolve in a unit
volume of solution. Aqueous Solubility is
the maximum concentration of a chemical
that will dissolve in pure water at a
reference temperature.
Soot: Carbon dust formed by incomplete
combustion.
Sorption: The action of soaking up or
attracting substances; process used in
many pollution control systems.
Source Area: The location of liquid
hydrocarbons or the zone of highest soil or
groundwater concentrations, or both, of
the chemical of concern.
Source Characterization Measurements:
Measurements made to estimate the rate
of release of pollutants into the environ-
ment from a source such as an incinerator,
landfill, etc.
Source Reduction: Reducing the amount
of materials entering the waste stream
from a specific source by redesigning
products or patterns of production or
consumption (e.g., using returnable bev-
erage 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).
Source-Water Protection Area: The area
delineated by a state for a Public Water
Supply or including numerous such
suppliers, whether the source is ground
water or surface water or both.
Sparge or Sparging: Injection of air below
the water table to strip dissolved volatile
organic compounds and/or oxygenate
ground water to facilitate aerobic biodeg-
radation of organic compounds.
Special Local-Needs Registration: Regis-
tration of a pesticide product by a state
agency for a specific use that is not
federally registered. However, the active
ingredient must be federally registered for
other uses. The special use is specific to
that state and is often minor, thus may not
warrant the additional cost of a full
federal registration process. SLN registra-
tion cannot be issued for new active
ingredients, food-use .active ingredients
without tolerances, or for a canceled
registration. The products cannot be
shipped across state lines.
44
Special Review: Formerly known as
Rebuttable Presumption Against Registra-
tion (RPAR), this is the regulatory process
through which existing pesticides suspect-
ed of posing unreasonable risks to human
health, non-target organisms, or the
environment are referred for review by
EPA. Such review requires an intensive
risk/benefit analysis with opportunity for
public comment. If risk is. found to
outweigh social and economic benefits,
regulatory actions can be initiated, rang-
ing from label revisions and use-restric-
tion to cancellation or suspended registra-
tion.
Special Waste: Items such as household
hazardous waste, bulky wastes (refrigera-
tors, pieces of furniture, etc.) tires, and
used oil.
Species: 1 A reproductively isolated
aggregate of interbreeding organisms
having common attributes and usually
designated by a common name. 2. An
organism belonging to belonging to such a
category.
Specific Conductance: Rapid method of
estimating the dissolved solid content of
a water supply by testing its capacity to
carry an electrical current.
Specific Yield: The amount of water a unit
volume of saturated permeable rock will
yield when drained by gravity.
Spill Prevention, Containment, and
Countermeasures Plan (SPCP): Plan
covering the release of hazardous sub-
stances 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
neutralizing the gas.
Spring: Ground water seeping out of the
earth where the water table intersects the
ground surface.
Spring Melt/Thaw: The process whereby
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, sometimes
causing fish kills.
Stabilization: Conversion of the active
organic matter in sludge into inert,
harmless material.
Stabilization Ponds: (See: lagoon.)
Stable Air: A motionless mass of air that
holds, instead of dispersing, pollutants.
Stack: A chimney, smokestack, or vertical
pipe that=discharges used air.
Stack Effect Flow of air resulting from
warm air rising, creating a positive
pressure area at the top of a building and
negative pressure area at the bottom. This
effect can overpower the mechanical
system and disrupt building ventilation
and air circulation.
Stack Gas: (See: flue gas.)
Stage II Controls: Systems placed on
service station gasoline pumps to control
and capture gasoline vapors during
refuelling.
Stagnation: Lack of motion in a mass of
air or water that holds pollutants in place.
Stakeholder: Any organization, govern-
mental entity, or individual that has a
stake in or may be impacted by a given
approach to environmental regulation,
pollution prevention, energy conserva-
tion, etc.
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 emissions
produced. EPA establishes minimum
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 by EPA, other federal agencies,
states or Principal Responsible Parties in
order to begin response actions at a
Superfund site.
State Emergency Response Commission
(SERC): Commission appointed by each
state governor according to the' require-
ments of SARA Title III. The SERCs
designate emergency planning districts,
appoint local emergency planning commit-
tees, and supervise and coordinate their
activities.
State Environmental Goals and Indica-
tion Project Program to assist state
environmental agencies by providing
technical and financial assistance in the
development of environmental goals and
indicators.
State Implementation Plans (SIP): EPA
approved state plans for the establish-
ment, regulation, and enforcement of air
pollution standards.
State Management Plan: Under FIFRA, a
state management plan required by EPA to
allow states, tribes, and U.S. territories the
flexibility to design and implement ways
to protect ground water from the use of
certain pesticides.
Static Water Depth: The vertical distance
from the centerline 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 producer
of pollution, mainly power plants and
other facilities using industrial combus-
tion processes. (See: point source.)
Sterilization: The removal or destruction
of all microorganisms, including patho-
genic and other bacteria, vegetative forms,
and spores.
Sterilizer: One of three groups of anti-
microbials registered by EPA for public
health uses. EPA considers an antimicro-
bial to be a sterilizer when it destroys or
eliminates all forms of bacteria, viruses,
and fungi and their spores. Because spores
are considered the most difficult form of
microorganism to destroy, EPA considers
the term sporicide to be synonymous with
sterilizer.
Storage: Temporary holding of waste
pending treatment or disposal, as in'.
containers, tanks, waste piles, and surface
impoundments.
Storm Sewer: A system of pipes (separate
from sanitary sewers) that carries water
runoff front buildings and land surfaces,
Stratification: Separating into layers.
Stratigraphy: Study of the formation,
composition, and sequence of sediments,
whether consolidated or not.
Stratosphere: The portion of the atmo-
sphere 10-to-25 miles above the earth's
surface. ,
Stressors: Physical, chemical, or biologi- -
cal entities that can induce adverse effects
on ecosystems or human health. .
•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
Subchronic Exposure: Multiple or con-
tinuous exposures lasting for approxi-
mately ten percent of an experimental
species lifetime, usually over -a three-
month period.
Submerged Aquatic Vegetation: Vegeta-
tion that' lives at or below the water
surface; an important habitat for young
fish and othr aquatic organisms.
Subwatershed: Topographic perimeter of
the catchment area of a stream tributary.
Sulfur Dioxide (SO2): A-pungent, color-
less, gas formed primarily by the
combustion of fossil fuels; becomes a
pollutant when present in large amounts.
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 residuals
so large as to require dechlorination.
Supercritical Water: A type of thermal
treatment using moderate temperatures
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 com-
pounds to form carbon dioxide and water.
Superfund: The program operated under
the legislative authority of CEJRCLA and
SARA that funds and carries.out EPAsolid
. waste emergency and long-term removal
and remedial activities. These activities
include establishing the National Priori-
ties List, investigating sites for inclusion
on the list, determining their priority, and
conducting and/or supervising cleanup
and other- remedial actions.
Superfund Innovative Technology Evalu-
ation (SITE) Program: EPA program to
promote development and use of innova-
tive treatment and site charachterization
technologies in Superfund site cleanups.
Supplemental Registration: An arrange-
ment whereby a registrant licenses
another company to market its pesticide
product under the second company's
registration. . •'. .
• Supplier of Water: Any person whp owns
or operates a public water supply
Surface Impoundment: Treatment,,stor-
age, or disposal .of liquid hazardous
wastes in ponds. - . .
Surf ace 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 trans-
porter of non-point source pollutants in
rivers, streams, .and lakes..
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, impoundments, seas,
estuaries, etc.) ,
Surf ace-Water Treatment KuJe.- Rule that
specifies maximum contaminant level
goals for Giardia lamblia, viruses, and
Legionella and promulgates filtration and
disinfection requirements for public water
systems using surface-water _or ground-
water sources under the direct influence of
surface water. The regulations also specify
water quality, treatment, and watershed
protection criteria under which filtration
may be avoided:
Surfacing ACM: Asbestos^containing ma-
terial that is sprayed or troweled on or
otherwise applied to surfaces, such as
acoustical plaster on ceilings and fire-
proofing 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. In-
cludes textured plaster, and other textured
wall and ceiling surfaces.
Surfactant: A detergent compound that
promotes lathering. "
Surrogate Data: Data from studies of test
organisms or a test substance that are used
to estimate the characteristics or effects on
another organism or substance.
Surveillance System: A series of monitor-
ing devices designed to check on environ-
mental conditions.
Susceptibility Analysis: An analysis to
determine whether a Public Water Supply
is subject to significant pollution from
known potential sources.
Susceptibility Analysis: An analysis to
determine whether a Public Water Supply
is subject to significant pollution from
known potential sources.
, Suspect Material: Building material sus-
pected of containing asbestos; e.g., surfac-
ing material, floor tile, ceiling tile, thermal
system insulation. .
Suspended Loads: Specific sediment
particle^ 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 surface
of, or are suspended in, sewage or other
liquids. They resist removal by conven-
tional means.
Suspension: Suspending the use of a
pesticide when EPA deems it necessary to
prevent an imminent hazard resulting
from its continued use. , An emergency
suspension takes effect immediately;,
under ah ordinary suspension a registrant
can request a hearing before the suspen-
sion goes into -effect. Such a hearing
process might take six months.
Suspension Culture: Cells growing in a
liquid nutrient medium.
45
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Swamp: A type of wetland dominated by
woody vegetation but without appre-
ciable peat deposits. Swamps maybe fresh
or salt water and tidal or non-tidal. (See:
wetlands.)
Synergism: An interaction of two or more
chemicals that results in an effect greater
than the sum of their separate effects.
Synthetic Organic Chemicals (SOCs):
Man-made (anthropogenic)-organic chemi-
cals. Some SOCs are volatile; others tend
to stay dissolved in water instead of
evaporating.
System With a Single Service Connec-
tion: A system that supplies drinking
water to consumers via a single service
line.
Systemic Pesticide: A chemical absorbed
by an organism that interacts with the
organism and makes the organism toxic to
pests.
Tail Water: The runoff of irrigation water
from the lower end of an irrigated field.
Tailings: Residue of raw material or waste
separated out during the processing of
crops or mineral ores.
Tailpipe Standards: Emissions limita-
tions applicable to mobile source engine
exhausts.
Tampering: Adjusting, negating, or re-
moving pollution control equipment on a
motor vehicle.
Technical Assistance Grant (TAG): As
part of the Superfund program, Technical
Assistance Grants of up to $50,000 are
provided to citizens' groups to obtain
assistance in interpreting information
related to cleanups at Superfund sites or
those proposed for the National Priorities
List. Grants are used by such groups to
hire technical advisors to help them
understand the site-related technical
information for the duration of response
activities.
Technical-Grade Active Ingredient
(TGA): A pesticide chemical in pure form
as it is manufactured prior to being
formulated into an end-use product (e.g.,
wettable powders, granules, emulsifiable
concentrates). Registered manufactured
products composed of such chemicals are
known as Technical Grade Products.
Technology-Based Limitations: Indus-
try-specific effluent limitations based on
best available preventive technology
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: Industry-
specific effluent limitations applicable to
46
direct and indirect sources which are
developed on a category-by-category
basis using statutory factors, not includ-
ing water-quality effects.
Teratogenesis: The introduction of nonhe-
reditary birth defects in a developing fetus
by exogenous factors such as physical or
chemical agents acting in the womb to
interfere with normal embryonic develop-
ment.
Terracing: Dikes built along the contour of
sloping farm land that hold runoff and
sediment to reduce erosion.
Tertiary Treatment: Advanced cleaning of
wastewater that goes beyond the second-
ary or biological stage, removing nutri-
ents such as phosphorus, nitrogen, and
most BOD and suspended solids. (See
Primary Treatment: Secondary Treatment)
Theoretical Maximum Residue Contri-
bution: The theoretical maximum amount
of a pesticide in the daily diet of an
average person. It assumes that the diet is
composed of all food items for which there
are tolerance-level residues of the pesti-
cide. The TMRC is expressed as milli-
grams of pesticide/kilograms of body
weight/day.
Therapeutic Index: The ratio of the dose
required to produce toxic or lethal effects
to the dose required to produce nonadverse
or therapeutic response.
Thermal Pollution: Discharge of heated
water from industrial processes that can
kill or injure aquatic organisms.
Thermal Stratification: The formation of
layers of different temperatures in a lake
or reservoir.
Thermal System Insulation (TSI): Asbes-
tos-containing material applied to pipes,
fittings, boilers, breeching, tanks, ducts, or
other interior structural components to
prevent heat loss or gain or water
condensation.
Thermal Treatment: Use of elevated
temperatures to treat hazardous wastes.
(See: incineration; pyrolysis.)
Thermocline: 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 chemical
at which a specified measurable effect is
observed and below which it is not
observed.
Threshold Level: Time-weighted average
pollutant concentration values, exposure
beyond which is likely to adversely affect
human health. (See: environmental expo-
sure).
Threshold Limit Value (TL\ft The
concentration of an airborne substance to
which an average person can be re-
peatedly exposed without adverse effects.
TLVs may be expressed in three.ways: (1)
TLV-TWA—Time weighted average, based
on an allowable exposure averaged over a
'normal 8-hour workday or 40-hour
workweek; (2) TLV-STEL—Short-term
exposure limit or maximum concentration
for a brief specified period of time,
depending on a specific chemical (TWA
must still be met); and (3) TLV-C—Ceiling
Exposure Limit or maximum exposure
concentration not to be exceeded 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 substances
that triggers notification by facilities to the
State Emergency Response Commission
that such facilities are subject to emer-
gency planning requirements under SARA
Title III.
Thropic Levels: Afunctional classification
of species that is based on feeding
relationships (e.g., generally aquatic and
terrestrial green plants comprise the first
thropic level, and herbivores comprise the
second.)
Tidal Marsh: Low, flat marshlands
traversed 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.
Time-weighted Average (TWA): In air
sampling, the average air concentratipn of
contaminants during a given period.
Tire Processor: Intermediate operating
facility where recovered tires are pro-
cessed in preparation for recycling.
Tires: As used in recycling, passenger car
and truck tires (excludes airplane, bus,
motorcycle and special service military,
agricultural, off-the-road and-slow speed
industrial tires). Car and truck tires are
recycled into rubber products such as
trash cans, storage containers, rubberized
asphalt or used whole for playground and
reef construction. -
Tolerance Petition: A formal request to
establish a new tolerance or modify an
existing one.
Tolerances: Permissible residue levels for
pesticides in raw agricultural produce
and processed foods. Whenever a pesti-
cide is registered for use on a food or a
feed crop, a tolerance (or exemption 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 morvtK- TKe rate at whicti a laivclfill
accepts waste is limited by the landfill's
permit.
Topography: The physical features of a
surface area including relative elevations
and the position of natural and man-made
(anthropogenic) features.
Total Dissolved Phosphorous: The total
phosphorous content of all material that
will pass through a filter, which is
determined as orthophosphate without
prior digestion pr hydrolysis. Also called
soluble P. or ortho P.,
Total Dissolved Solids (TDS): All mate-
rial that passes the standard glass river
filter; how called total filtrable residue.
. Term is used to reflect salinity. *
Total Petroleum Hydrocarbons (TPH):
Measure of the concentration or mass of
• petroleum hydrocarbon constituents
present in a'given amount of soil or water.
The word "total" is a misnomer—few, if
any, of the procedures for quantifying
. hydrocarbons can measure all of them.in a.
given sample. Volatile ones are usually
lost in the process and not'quantified and
non-petroleum hydrocarbons sometimes
appear in the analysis. *
Total Recovered Petroleum Hydrocar-
bon: A method for measuring petroleum
hydrocarbons in samples of soil or water.
Total Suspended Particles (TSP): A
method of monitoring, airborne par-
ticulate matter by total weight. .
Total Suspended Solids (TSS): A measure
of the suspended solids in wastewater,
effluent, or water bodies, determined by
tests for "total suspended non-filterable
solids." (See: suspended solids.)
Toxaphene: Chemical that causes adverse
health effects in- domestic water supplies
and is toxic to fresh water and marine
aquatic life.
Toxic Chemical: Any chemical listed in
EPA rules as "Toxic Chemicals Subject to
Section 313 of the Emergency Planning
and Community Right-to-Know Act of
1986." . ,. -
Toxic Chemical Release Form: Informa-
tion form required of facilities that
manufacture, process, or use (in quantities
above a specific amount) chemicals listed
under SARA Title III.
Toxic Chemical Use Substitution: Replac-
ing toxic chemicals with less harmful
chemicals in industrial p'rbcesses. !
Toxic Cloud: Airborne plume of gases,
vapors, fumes, or aerosols containing
toxic materials.
Toxic Concentration: the concentration at
which a substance produces a toxic effect.
Toxic Dose: The dose level at which a
substance produces a toxic effect.
Toxic Pollutants: Materials that cause
death, disease, or birth defects in
organisms that ingest or absorb them. The
quantities and exposures necessary 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 mixture
that may present an unreasonable risk of.
injury to health or the environment.
Toxic Waste: A waste that can produce
injury if inhaled, swallowed, or absorbed
through the skin.
Toxicant: A harmful substance or agent
that may injure an exposed organism.
Tbxicity: The degree to which a substance
or mixture of substances can , harm
humans or animals. Acute toxicity involves
harmful effects'in an organism through a
single or short-term exposure Chronic
toxicity is the ability of a substance or
mixture of substances to cause .harmful
effects over an extended period, usually
upon repeated or continuous exposure
sometimes lasting for the entire life of the
exposed organism. Subchronic toxicity is
the ability of the substance to cause effects
for more than one year but less than the
lifetime of the exposed organism. -
Toxicity Assessment: Characterization of
the toxicological properties and effects of
a chemical, with special emphasis on
establishment of dose-response character-
istics. , '•'".' ,
Toxicity Testing: Biological testing (usual-
ly with an invertebrate, fish, or small
mammal) to determine the adverse effects
of a compound or effluent.
Toxicological Profile: An examination,
summary, and interpretation of a hazard-
ous substance to determine level's . of
exposure and associated health effects.
Transboundary Pollutants: Air pollution
that travels from one jurisdiction to
.another, often crossing state or interna-
tional boundaries. Also applies to water
pollution.
Transfer Station: Facility where solid
.waste is transferred from collection
vehicles to larger trucks or rail cars for
longer distance transport.
Transient Water System: A non-commu-
nity water system that does not serve 25 of
the same nonresidents per day for more
than six months per year.
Transmission Lines:,Pipelines that trans-
port raw water from its source to a water
treatment plant, then to the distribution
grid system.
Transmissivity: The ability of an aquifer
to transmit water.
Transpiration: The \piocess 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 reduce
vehicular emission and improve air
quality by reducing or changing the flow
of traffic; e.g., bus and HOV lanes,
carpopling and other forms of ride-
shairing, public transit, bicycle lanes,
Transporter: Hauling firm that picks up
properly packaged and labeled hazardous -
waste from generators and transports it to
designated facilities for treatment, stor-
age, or disposal. Transporters are subject
to EPA and DOT hazardous waste
regulations.
Trash: Material considered worthless or
offensive that is thrown away. Generally
defined as dry waste material, but in
common usage it is a synonym for
garbage, rubbish, or refuse.
Trash-to-Energy Plan: Burning trash to
produce energy. ; . -
, Treatabijhy Studies: Tests of potential
cleanup technologies conducted in a
laboratory (See: bench-scale tests.)
Treated Regulated Medical Waste: Medi-
cal waste treated to substantially reduce or
eliminate its pathogenicity, but that has
not yet. been destroyed.
Treated Wastewater: Wastewater that hs
been subjected to one or more physical,
chemical, and biological processes to
reduce its potential of being a health
hazard.
Treatment: (1) Any method, technique, or
process designed to remove solids and/or
pollutants from solid waste, waste-
streams, effluents, and air emissions. (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. '
Treatment Plant: A structure built to treat
wastewater before discharging it into the
environment.
Treatment, Storage, and Disposal Facil-
ity: Site where a hazardous substance 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, particula-
tes, and hydrogen chloride.
Trichloroethylene (TCE): A stable, low
boiling-point colorless liquid, toxic if
inhaled. Used as a solvent or metal
47
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degreasing agent, and in other industrial
applications.
Trickle Irrigation: Method in which water
drips to the soil from perforated tubes or
emitters.
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.
Trihalomethane (THM): One of a family
of organic compounds named as deriva-
tive of methane. THMs are generally by-
products of chlorination of drinking water
that contains organic material.
Troposhpere: The layer of the atmosphere
closest to the earth's surface.
Trust Fund (CERCLA): A fund set up
under the Comprehensive Environmental
Response, Compensation and Liability
Act (CERCLA) to help pay for cleanup of
hazardous waste sites and for legal action
to force those responsible for the sites to
clean them up.
Tube Settlen 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 basins and clarifiers to
improve particle removal.
Tuberculation: Development or forma-
tion of small mounds of corrosion
products on the inside of iron pipe. These
tubercules roughen the inside of the pipe,
increasing its resistance to water flow.
Tundra: A type of treeless ecosystem
dominated by lichens, mosses, grasses,
and woody plants. Tundra is found at
high latitudes (arctic tundra) and high
altitudes (alpine tundra). Arctic tundra is
underlain by permafrost and is usually
water saturated. (See: wetlands.)
Turbidimeten A device that measures the
cloudiness of suspended solids in a liquid;
a measure of the quantity of suspended
solids.
Turbidity: 1. Haziness in air caused by the
presence of particles and pollutants. 2. A
cloudy condition in water due to suspend-
ed silt or organic matter.
U
Ultra Clean Coal (UCC): Coal that is
washed, ground into fine particles, then
chemically treated to remove sulfur, ash,
silicone, and other substances; 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. UV rays from
other parts of the spectrum (UV-B) can
cause skin cancer or other tissue damage.
The ozone layer in the atmosphere partly
shields us from ultraviolet rays reaching
the earth's surface.
Uncertainty Factor: One of several factors
used in calculating the reference dose
from experimental data. UFs are intended
to account for (1) the variation in
sensitivity among, humans; (2) the uncer-
tainty in extrapolating' animal data to
humans; (3) the uncertainty in extrapolat-
ing data obtained in a study that covers.
less than the full life of the exposed animal
or human; and (4) the uncertainty in using
LOAEL data rather than NOAEL data.
Unconfined Aquifer: An aquifer contain-
ing water that is not under pressure; 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 Injection Wells: Steel- and
concrete-encased shafts into which haz-
ardous waste is deposited by force and
under pressure.
Underground Sources of Drinking Wa-
ter. 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 (UST): Atank
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.
Unsaturated Zone: The area above the
water table where soil pores are not fully
saturated, although some water may be
present. (See: vadose zone)
Upper Detection Limit: The largest
concentration that an instrument can
reliably detect.
Uranium Mill Tailings Piles: Former
• uranium ore processing sites that contain
leftover radioactive materials (wastes),
including radium and unrecovered urani-
um.
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 commer-
cial properties that carries pollutants of
various kinds into the sewer systems and
receiving waters.
Urea-Formaldehyde Foam Insulation: A
material once used to conserve energy by
sealing crawl spaces, attics, etc.; no longer
used because emissions were found to be a
health hazard.
Use Cluster:Aset of competing chemicals,
processes, and/or technologies that can
substitute for one another in performing a
particular function.
Used Oil: Spent motor oil from passenger
cars and trucks collected at specified
locations for recycling (not included in the
category of municipal solid waste).
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 demand
for a utility district.
V
Vadose Zone: The zone between land
surface and the water table within which
the moisture content is less than satura-
tion (except in the capillary fringe) and
pressure is less than atmospheric. Soil
pore space also typically contains air or
other gases. The capillary fringe is
included in the vadose zone. (See:
Unsaturated Zone.)
Valued Environmental Attributes/Com-
ponents: Those aspects (components/
processes/functions) of ecosystems, hu-
man health, and environmental welfare
considered to be important and poten- '
tially at risk from human activity or
natural hazards. Similar to the term
"valued environmental components" used
in environmental impact assessment.
Vapor Capture System: Any combination
of hoods and ventilation system that
captures or contains organic vapors so
they may be directed to an abatement or
recovery device.
Vapor Dispersion: The movement of
vapor clouds in air due to wind, thermal
action, gravity spreading, and mixing.
Vapor Plumes: Flue gases visible because
they contain water droplets.
Vapor Pressure: Ameasure of a substance's
propensity to evaporate, vapor pressure is
the force per unit area exerted by vapor in
an equilibrium state with surroundings at
a given pressure. It increases exponen-
tially with an increase in temperature. A
relative measure of chemical volatility,
vapor pressure is used to calculate water
partition coefficients and volatilization
rate constants.
48
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Variance: Government permission for a
delay or exception in the application of a
given law, ordinance, .or regulation.
Vector: 1. An organism, often an-insect or •
rodent, that carries disease. 2. Plasmids,
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
minimize loss of pollutants.
Vehicje Miles Travelled (VMT): A mea-
sure of the extent of motor vehicle
operation; the total number of vehicle
miles travelled within a specific geo-
graphic area over a given period of time.
Ventilation Rate: The rate at which indoor
air enters and leaves a building. Ex-
pressed as the number of changes of
outdoor air per unit of time (air changes
per hour (ACH), or the rate at which a
volume of outdoor air enters in cubic feet
per minute (CFM),
Ventilation/Suction: The act of admitting
fresh air into a space in order to replace"
stale or contaminated air; achieved by
blowing air into the space. Similarly,
suction represents, the admission of fresh
air into an interior space by lowering the
pressure outside of the space, thereby"
drawing the contaminated air outward.
Venturi Scrubbers: Air pollution control
devices that use water to remove particu-
late 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.
Viscosity: The molecular friction within a
fluid that produces flow resistance.
Volatile: Any, substance that evaporates
readily.
Volatile Liquids: Liquids which easily
vaporize or evaporate at room tempera-'
ture. ,.
Volatile Organic Compound (VOC): Any
organic compound that participates in
atmospheric photochemical reactions ex-
cept those designated by EPA as having
negligible photochemical 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 compacting,
shredding, incineration, or composting.
Volumetric Tank Test: One of several tests
to determine the physical integrity of a
storage tank; the volume of fluid in the
tank is measured directly or calculated
"from product-level changes. A marked
drop in volume indicates a leak.
Vulnerability Analysis: Assessment of
elements in the community that are
susceptible to damage if hazardous
materials are released.
Vulnerable Zone: An area over which the
airborne concentration of a chemical
accidentally released could reach the level
of concern.
W -
Waste: 1. Unwanted materials left over
from a manufacturing process. 2. Refuse
from, places of human or'animal habita-
tion.
Waste Characterization: Identification of
chemical and microbiological constituents
of a waste material. • •
Waste Exchange: Arrangement in which
companies exchange their wastes for the
benefit of both parties.
Waste Feed: The continuous or intermit-
tent flow oŁ wastes into an incinerator.
Waste Generation: The weight or volume
of materials and products that enter the
waste stream before recycling, composting,
landfilling, or combustion takes place.
Also can represent the amount of waste
generated by a given source or category of
sources.1
Waste Load Allocation: 1. The maximum
load of pollutants each discharger of
waste is allowed to release into a
particular waterway. Discharge limits are
usually required for each specific water
quality criterion being, or expected 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 applied to recycling
and other efforts to reduce the amount of
waste going into the waste stream.
Waste Piles: Non-containerized, lined or
unlined accumulations of solid,
nonflowing waste.
' Waste Reduction: Using source reduction,
recycling, or composting to prevent or
reduce waste generation.
Waste Stream: The total flow of solid,
waste from homes, businesses, institu-
tions, and manufacturing 'plants that is
recycled, burned, or disposed of in
landfills,, or segments thereof such as the
"residential Waste stream" or the "recy-
clable waste stream."
Waste Treatment Lagoon: Impoundment
made by excavation or earth fill for
biological treatment of wastewater.
Waste Treatment Plant: A facility contain-
ing a series of tanks, screens, filters and
other processes by which pollutants are
removed from water.
Waste Treatment Stream: The continuous
movement of waste from generator to
treater and disposer.
Waste-Heat Recovery:. Recovering heat
discharged as a byproduct of one process
to provide heat needed by a second
process.;
Waste-to-Energy Facility/Municipal-
Waste Combustor: Facility where recov-
ered-municipal solid waste-is converted
into a usable form of energy, usually via
combustion.
Wastewater: The spent or used water from
a home, community, farm, or industry that
contains dissolved or suspended
matter.Water Pollution: The presence in
water of enough harmful or objectionable
material to damage the water's quality.
Wastewater Infrastructure: The plan'or
network for the collection, treatment, and
disposal of sewage in a community. The
level of treatment will depend on the size
of the community,'the type of discharge,
and/or the designated use of the receiving
water.
Wastewater Operations • and Mainte-
nance: Actions taken after construction to
ensure that facilities Constructed to treat
wastewater will be operated, maintained,
and managed to reach prescribed effluent
levels in an optimum manner.
Water Purveyor: A public utility, mutual
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, swimming, farming, fish produc-
tion, or industrial processes.
Water Quality Standards: State-adopted
and EPA-approyed ambient standards 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: Efflu-
ent limitations applied to dischargers •
when mere technology-based limitations
would cause violations of water quality
standards. Usually applied to discharges
into small streams.
:49
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Water Quality-Based Permit: A permit
with an effluent limit more stringent than
one based on technology performance.
Such limits may be necessary to protect
the designated use of receiving waters
(e.g., recreation, irrigation, industry or
water supply).
Water Solubility: The maximum possible
concentration of a chemical compound
dissolved in water. If a substance is water
soluble it can very readily disperse
through the environment.
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 groundwater.
Water Treatment Lagoon: An impound
for liquid wastes designed to accomplish
some degree of biochemical treatment.
Water Well: An excavation where the
intended use is for location, acquisition,
development, or artificial recharge of
ground water.
Water-Soluble Packaging: Packaging that
dissolves in water; used to reduce
exposure risks to pesticide mixers and
loaders.
Water-Source Heat Pump: Heat pump
that uses wells or heat exchangers to
transfer heat from water to the inside of a
building. Most such units use ;ground
water. (See: ground-source heat pump;
heat pump.)
Waterbome Disease Outbreak: The sig-
nificant occurence of acute illness associ-
ated with drinking water from a public
water system that is deficient in treatment,
as determined by appropriate local or
state agencies.
Watershed: The land area that drains into
a stream; the watershed for a major river
may encompass a nummber of smaller
watersheds that ultimately combine at a
common point.
Watershed Approach: A coordinated
framework for environmental manage-
ment that focuses public and private
efforts on the highest priority problems
within hydrologically-defined geographic
areas taking into consideration both
ground and surface water flow.
Watershed Area: A topographic area
within a line drawn connecting the
highest points uphill of a drinking water-
intake into which overland flow drains.
Weight of Scientific Evidence: Consider-
ations in assessing the interpretation of
published information about toxicity—
quality of testing methods, size and power
of study design, consistency of results
across studies, and biological plausibility
of exposure-response relationships and
statistical associations.
Weir: 1. A wall or plate placed in anjapen
channel to measure the flow of water. 2. A
wall or obstruction used to control flow
from settling tanks and clarifiers to ensure
a uniform flow rate and avoid short-
circuiting. (See: short-circuiting.)
Well: Abored, 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 emplace-
ment of fluids into a well.
Well Monitoring: Measurement by on-
site instruments or laboratory methods of
well water quality.
Well Plug: A watertight, gastight seal
installed in a bore, hole or well to prevent
movement of fluids.
Well Point: Ahollow vertical tube, rod, or
pipe terminating in a perforated pointed
shoe and fitted with a fine-mesh screen.
Wellhead Protection Area: A protected
surface and subsurface zone surrounding
a well or well field supplying a public
water system to keep contaminants from
reaching the well water.
Wetlands: An area that is saturated by
surface or ground water with vegetation
adapted for life under those soil condi-
tions, as swamps, bogs/fens, marshes, and
estuaries.
Wettability: The relative degree to which
a fluid will spread into or coat a solid
surface in the presence of other immiscible
fluids.
Wettable Powder: Dry formulation that
must be mixed with water or other liquid
before it is applied.
Wheeling: The transmission of electricity
owned by one entity through the facilities
owned by another (usually a utility).
Whole-Effluent-Toxicity Tests: Tests to
determine the toxicity levels of the total
effluent from a single source as opposed to
a series of tests for individual contami-
nants.
Wildlife Refuge: An area designated for
the protection. of wild animals, within
which hunting and fishing are either
prohibited or strictly controlled.
Wire-to-Wire Efficiency: The efficiency of
a pump and motor together.
Wood Packaging: Wood products such as
pallets, crates, and barrels.
Wood Treatment Facility: An industrial
facility that treats lumber and other wood
products for outdoor use. The process
employs chromated copper arsenate,
which is regulated as a hazardous
material.
Wood-Burning-Stove Pollution: Air pollu-
tion caused by emissions of p articulate
matter, carbon monoxide, total suspended
particulates, and polycyclic organic mat-
ter from wood-burning stoves,
Working Level (WL): A unit of measure
for documenting exposure to radon decay
products, the so-called "daughters." One
working level is equal to approximately
200 picocuries per liter.
Working Level Month (WLM): A unit of
measure used to determine cumulative
exposure to radon.
Xenobiota: 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 other garden refuse.
Yellow-Boy:Iron. oxide flocculant (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 of water (expressed as
a rate of flow or total quantity per year)
that can be collected for a given use from
surface or groundwater sources:
Zero Air: Atmospheric air purified to
contain less than 0.1 ppm. total hydrocar-
bons.
50
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A&I: Alternative and Innovative
(Wastewater Treatment System)
AA: Accountable Area; Adverse Action;
Advices of Allowance; Assistant Admin-
istrator; Associate Administrator; Atomic
Absorption
AAEE: American Academy of Environ-
mental Engineers
AANWR: Alaskan Arctic National
Wildlife Refuge x . ;
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 ability to pay a
civil penalty.
ABES: Alliance for Balanced Environ-
mental Solutions
AC: Actual Commitment. Advisory
Circular
A&C: Abatement and Control
AC A: American Conservation Associa-
. tion
ACBM: Asbestos-Containing Buildirig
Material '
ACE: Alliance for Clean Energy •
ACE: Any Credible Evidence
ACEEE: American Council for an Energy
Efficient Economy
ACFM: Actual Cubic Feet Per Minute
ACL: Alternate Concentration Limit.
Analytical Chemistry Laboratory
ACM: Asbestos-Containing Material
ACP: Agriculture Control Program
(Water Quality Management); ACP: Air
Carcinogen Policy
ACQUIRE: Aquatic Information Re-
trieval -
ACQR: Air Quality Control Region
ACS: American Chemical Society
ACT: Action
ACTS: Asbestos Contractor Tracking
System. • ' ' ,
ACWA: American Clean Water Associa-
tion
ACWM: Asbestos-Containing Waste
Material
AD ABA: Acceptable Data Base
ADB: Applications Data Base
ADI: Acceptable Daily Intake
ADP: AHERA Designated Person;
Automated Data Processing
ADQ: Audits of Data Quality
ADR: Alternate Dispute Resolution
ADSS: ;Air Data Screening System
ADT: Average Daily Traffic
AEA: Atomic Energy Act
ABC: Associate Enforcement Counsels
AEE: Alliance for Environmental
Education
AEERL: Air and Energy Engineering
Research Laboratory
AEM: Acoustic Emission Monitoring
AERE: Association of Environmental
and Resource Economists
AES: Auger Electron Spectrometry
AFA: American Forestry Association
AFCA: Area Fuel Consumption Alloca-
tion •
AFCEE: Air Force Center for Eriviron- .
mental Excellence
AFS: AIRS Facility Subsystem
AFUG: AIRS Facility Users Group
AH: Allowance Holders
AHERA: Asbestos Hazard Emergency
- Response Act
AHU: Air Handling Unit.:
AI: Active Ingredient •
AIC: Active to Inert Conversion
AICUZ: Air Installation Compatible Use
Zones
AID: Agency for International Develop-
ment
AIHC; American Industrial Health
Council
AIP: Auto Ignition Point
AIRMON: Atmospheric Integrated
Research Monitoring Network
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 Achiev-
able .',.'•'
ALC: Application Limiting Constituent
ALJ: Administrative Law Judge
ALMS: Atomic Line Molecular Spectros-
copy
ALR: Action Leakage Rate
AMBIENS: Atmospheric Mass Balance
of Industrially Emitted and Natural...
Sulfur
AMOS: Air Management Oversight
System . . •
AMPS: Automatic Mapping and
Planning System
AMSA: Association of Metropolitan
Sewer Agencies
ANC: Acid Neutralizing Capacity
ANPR: Advance Notice of Proposed
Rulemaking
ANRHRD: Air, Noise, & Radiation
Health Research Division/ORD
ANSS: American Nature Study Society
AOAC: Association of Official Analytical
Chemists
AOC: Abnormal Operating Conditions
AOD: Argon-Oxygen Decarbonization
AOML: Atlantic Oceanographic and -
Meteorological Laboratory
AP: Accounting Point
APA: Administrative Procedures Act
APCA: Air Pollution Control Association
APCD: Air Pollution Control District
APDS: Automated Procurement Docu-
mentation System
APHA: American Public Health Associa-
tion .
APRAC: Urban Diffusion Model for
Carbon Monoxide from Motor Vehicle
Traffic '
APTI: Air Pollution Training Institute
APWA: American Public Works Associa-
tion
AQ77: Non-reactive Pollutant Modelling
AQCCT: Air-Quality Criteria and
Control Techniques
AQCP: Air Quality Control Program
AQCR: Air-Quality Control Region
AQD: Air-Quality Digest .
AQDHS: Air-Quality Data Handling
System
AQDM: Air-Quality Display Model.
AQMA: Air-Quality Maintenance Area
AQMD: Air Quality Management
District
AQMP: Air-Quality Maintenance Plan.
AQSM: Air-Quality Simulation Model
AQTAD: Air-Quality Technical Assis-
tance Demonstration
- - S"
AR: Administrative Record
51
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A&R: Air and Radiation
ARA: Assistant Regional Administrator;
Associate Regional Administrator
ARAC: Acid Rain Advisory Committee
ARAR: Applicable or Relevant and
Appropriate Standards, Limitations,
Criteria, and Requirements
ARE: Air Resources Board
ARC: Agency Ranking Committee ,
ARCC: American Rivers Conservation
Council
ARCS: Alternative Remedial Contract
Strategy
ARG: American Resources Group
ARIP: Accidental Release Information
Program
ARL: Air Resources Laboratory
ARM: Air Resources Management
ARNEWS: Acid Rain National Early
Warning Systems
ARO: Alternate Regulatory Option
ARRP: Acid Rain Research Program
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 Administrators
ASHAA: Asbestos in Schools Hazard
Abatement Act
ASHRAE: American Society of Heating,
Refrigerating, and Air-Conditioning
Engineers
ASIWCPA: Association of State and
Interstate Water Pollution Control
Administrators
ASMDHS: Airshed Model Data Han-
dling System
ASRL: Atmospheric Sciences Research
Laboratory
AST: Advanced Secondary (Wastewater)
Treatment
ASTHO: Association of State and
Territorial Health Officers
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
52
ATS: Action Tracking System; Allow-
ance Tracking System
ATSDR: Agency for Toxic Substances
and Disease Registry
ATTF: Air Toxics Task Force
AUSM: Advanced Utility Simulation
Model
A/WPR: Air/Water Pollution Report
AWRA: American Water Resources
Association
AWT: Advanced Wastewater Treatment.
AWWA: American Water Works
Association
AWWARF: American Water Works
Association Research Foundation.
B
BAA: Board of Assistance Appeals
BAG: Bioremediation Action Committee;
Biotechnology Advisory Committee
BACM: Best Available Control Measures
BACT: Best Available Control Technol-
ogy
BADT: Best Available Demonstrated
Technology
BAF: Bioaccumulation Factor
BaP: Benzo(a)Pyrene
BAP: Benefits Analysis Program
BART: Best Available Retrofit Technol-
ogy
BASIS: Battelle's Automated Search
Information System
BAT: Best Available Technology
BATEA: Best Available Treatment
Economically Achievable
BCT: Best Control Technology
BCPCT: Best Conventional Pollutant
Control Technology
BOAT: Best Demonstrated Achievable
Technology
BDCT: Best Demonstrated Control
Technology
BDT: Best Demonstrated Technology
BEJ: Best Engineering Judgement. Best
Expert Judgment
BF: Bonafide Notice of Intent to
Manufacture or Import (IMD/OTS)
BID: Background Information Docu-
ment. Buoyancy Induced Dispersion
BIOPLUME: Model to Predict the
Maximum Extent of Existing Plumes
BMP: Best Management Practice(s)
BMR: Baseline Monitoring Report
BO: Budget Obligations
BOA: Basic Ordering Agreement
(Contracts)
BOD: Biochemical Oxygen Demand.
Biological Oxygen Demand
BOF: Basic Oxygen Furnace
BOP: Basic Oxygen Process
BOPF: Basic Oxygen Process Furnace
BOYSNC: Beginning of Year Significant
Non-Compliers
BP: Boiling Point
BPJ: Best Professional Judgment
BPT: Best Practicable. Technology. Pest
Practicable Treatment
BPWTT: Best Practical Wastewater
Treatment Technology
BRI: Building-Related Illness
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 Agreements. Corrective
Action
CAA: Clean Air Act; Compliance
Assurance Agreement
CAAA: Clean Air Act Amendments
CAER: Community Awareness and
Emergency Response
CAFE: Corporate Average Fuel Economy
CAFO: Concentrated Animal Feedlot;
Consent Agreement/Final Order
CAG: Carcinogenic Assessment Group
CAIR: Comprehensive Assessment of
Information Rule
CALINE: California Line Source Model
CAM: Compliance Assurance Monitor-
ing rule; Compliance Assurance Moni-
toring
CAMP: Continuous Air Monitoring
Program
CAN: Common Account Number
CAO: Corrective Action Order
CAP: Corrective Action Plan. Cost"
Allocation Procedure. Criteria Air
Pollutant
CAPMoN: Canadian Air and
Precipitatiion Monitoring Network
CAR: Corrective Action Report
-------
CA.S-. Center for AutomotiveSafety-
ChemicalAbstract Service
CASAC: Clean Air Scientific Advisory
Committee '
\ CASLP: Conference on Alternative State
and Local Practices
. CASTNet: Clean Air Status and Trends
Network .
CATS: Corrective Action Tracking
System .
CAU: Carbon Adsorption Unit; Com-
mand Arithmetic Unit
CB: Continuous Bubbler
CBA: Chesapeake Bay Agreement. Cost
Benefit Analysis
CBD: Central Business District
CBEP: Community Based Environmental
Project
CBI: Compliance Biompnitoring Inspec-
tion; Confidential Business Information
CBOD: Carbonaceous Biochemical
Oxygen Demand
CBP: Chesapeake Bay Program; County
Business Patterns
CCA: Competition in Contracting Act
CCAA: Canadian Clean Air Act
CCAP: Center for Clean Air Pplicy;
Climate Change Action Plan
CCEA: Conventional Combustion
Environmental Assessment
CCHW: Citizens Clearinghouse for
Hazardous Wastes •
CCID: Confidential Chemicals Identifi-
cation System
CCMS/NATO: Committee on Chal-
lenges of a Modern Society/
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 Administrator
CDBG: Community Development Block
Grant ' i .
CDD: Chlorinated dibenzo-p-dioxin
CDF: Chlorinated dibenzofuran
CDHS: Comprehensive Data Handling
System •
GDI: Case Development Inspection
CDM: Climatological Dispersion Model;
Comprehensive Data Management
CDMQCt Climatological Dispersion
Model with Calibration and Source
Contribution
CDNS: Climatological Data National
Summary
CDP: Census Designated Places
CDS: Compliance Data System.
CE: Categorical Exclusion. Conditionally
Exempt Generator , .-'-,-
CEA: Cooperative Enforcement Agree-
ment; Cost and Economic Assessment
CE AT: Contractor Evidence Audit Team
-CEARC: Canadian Environmental
Assessment Research Council
CEB: Chemical Element Balance
CEC: Commission for Environmental
Cooperation
CECATS: CSB Existing Chemicals
Assessment Tracking System
CEE: Center for Environmental Educa-
tion
CEEM: Center for Energy and. Environ- -.
' mental Management '
CEI: Compliance Evaluation Inspection
CELRF: Canadian Environmental Law
, Research Foundation
CEM: Continuous Emissiori Monitoring
CEMS: Continuous Emission Monitoring
System
CEPA: Canadian Environmental Protec-
tion Act
CEPP: Chemical Emergency Prepared-
ness Plan
CEQ: Council on Environmental Quality
CERCLA: Comprehensive Environmen-
Jtal Response, Compensation, and
Liability Act (1980)
CERCLIS: Comprehensive Environmen-
tal Response, Compensation, and
Liability .Information System
CERT: Certificate of Eligibility
CESQG: Conditionally Exempt Small
Quantity Generator
CEST: Community Environmental
Service Teams .
CF: Conservation Foundation
CFC: Chlorofluorocarbons
CFM: Chlorbfluoromethanes
CFR: Code of Federal Regulations .
CHABA: Committee on Hearing and
Bio-Acoustics
CHAMP: Community Health Air
Monitoring Program
CHEMNET: Chemical Industry Emer-
gency Mutual Aid-Network
CHESS: Community Health and
Environmental Surveillance System
CHIP: Chemical Hazard Information
Profiles
CI: Compression Ignition. Confidence
Interval •
CIAQ: Council on Indoor Air Quality
CIBL: Convective Internal Boundary
Layer
CICA: Competition in Contracting Act
CICISt Chemicals in Commerce Informa-
tion System '
CIDRS: Cascade Impactor Data Reduc-
tion System
,CIMI: Committee on Integrity and
Management Improvement
CIS:'Chemical Information System.
Contracts Information System
CKD: Cement Kiln Dust
CKRC: Cement Kiln Recycling Coalition
CLC: Capacity Limiting Constituents
CLEANS: Clinical Laboratory for
Evaluation and Assessment of
Toxic Substances
CLEVER: Clinical Laboratory for
Evaluation and Validation of Epidemio-
logic Research '
CLF: Conservation Law Foundation .
CLI: ConsumerLabelling Initiative
CLIPS: Chemical List Index and ProcessV
ing System
CLP: Contract Laboratory Program
CM: Corrective Measure
CMA: Chemical Manufacturers Associa- •
tion
CMBr Chemical Mass Balance
CME: Comprehensive Monitoring
Evaluation -.
CMEL: Comprehensive Monitoring
Evaluation Log
CMEP: Critical Mass Energy Project
CNG: Compresed Natural Gas
COCO: Contractor-Owned/ Contractor-
Operated ,
COD; Chemical Oxygen Demand
COH: Coefficient Of Haze
CPDA: Chemical Producers and Dis-
tributor Association
CPF: Carcinogenic Potency Factor
CPO: Certified Project Officer
CQA: Construction Quality Assurance
CR: Continuous Radon Monitoring
CROP: Consolidated Rules of Practice .
•53
-------
CRP: Child-Resistant Packaging;
Conservation Reserve Program
CRR: Center for Renewable Resources
CRSTER: Single Source Dispersion
Model
CSCT: Committee for Site Characteriza-
tion
CSGVVPP: Comprehensive State Ground
Water Protection Program
CSI: Common Sense Initiative; Compli-
ance Sampling Inspection
CSIN: Chemical Substances Information
Network
CSMA: Chemical Specialties Manufac-
turers Association
CSO: Combined Sewer Overflow
CSPA: Council of State Planning
Agencies
CSRL: Center for the Study of Respon-
sive Law
CTARC: Chemical Testing and Assess-
ment Research Commission
CTG: Control Techniques Guidelines
CTSA: Cleaner Technologies Subsitutes
Assessment
CV: Chemical Vocabulary
CVS: Constant Volume Sampler
CVV: Continuous working-level monitor-
ing
CWA: Clean Water Act (aka FWPCA)
CWAP: Clean Water Action Project
CWTC: Chemical Waste Transportation
Council
CZMA: Coastal Zone Management Act
CZARA: Coastal Zone Management Act
Reauthorization Amendments
D
DAPSS: Document and Personnel
Security System (IMD)
DBF: Disinfection By-Product
DCI: Data Call-In
DCO: Delayed Compliance Order,
DCO: Document Control Officer
DDT: DichloroDiphenylTrichloroethane
DERs: Data Evaluation Records
DBS: Diethylstilbesterol
DIE: Design for the Environment
DI: Diagnostic Inspection
DMR: Discharge Monitoring Report
DNA: Deoxyrifaonucleic acid
54
DNAPL: Dense Non-Aqueous Phase
Liquid
DO: Dissolved Oxygen
DOW: Defenders Of Wildlife
DP A: Deepwater Ports Act
DPD: Method of Measuring Chlorine
Residual in Water
DQO: Data Quality Objective
DRE: Destruction and Removal Effi-
ciency
ORES: Dietary Risk Evaluation System
DRMS: Defense Reutilization and
Marketing Service
DRR: Data Review Record
DS: Dichotomous Sampler
DSAP: Data Self Auditing Program
DSCF: Dry Standard Cubic Feet
DSCM: Dry Standard Cubic Meter
DSS: Decision Support System; Domestic
Sewage Study
DT: Detectors (radon) damaged or lost;
Detention Time
DU: Decision Unit. Ducks Unlimited;
Dobson Unit
DUC: Decision Unit Coordinator
DWEL: Drinking Water Equivalent Level
DWS: Drinking Water Standard
DWSRF: Drinking Water State Revolv-
ing Fund
EA: Endangerment Assessment; Enforce-
ment Agreement; Environmental Action;
Environmental Assessment;. Environ-
mental Audit
EAF: Electric Arc Furnaces
BAG: Exposure Assessment Group
EAP: Environmental Action Plan
EAR: Environmental Auditing
Roundtable
EASI: Environmentl Alliance for Senior
Involvement
EB: Emissions Balancing
EC: Emulsifiable Concentrate; Environ-
ment Canada; 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 Labora-
tory
ECOS: Environmental Council of the
States
ECR: Enforcement Case Review
ECRA: Economic Cleanup Responsibility
Act
ED: Effective Dose
EDA: Emergency Declaration Area
EDB: Ethylene Dibromide
EDC: Ethylene Dichloride
EDD: Enforcement Decision Document
EDF: Environmental Defense Fund
EDRS: Enforcement Document Retrieval
System
EDS: Electronic Data System; Energy
Data System
EDTA: Ethylene Diamine Triacetic Acid
EDX: Electronic Data Exchange
EDZ: Emission Density Zoning
EEA:~ Energy and Environmental
Analysis
EECs: Estimated Environmental
Concentrations
EER: Excess Emission Report
EERL: Eastern Environmental Radiation
Laboratory
EERU: Environmental Emergency
Response Unit
EESI: Environment and Energy Study
Institute
EESL: Environmental Ecological and
Support Laboratory
EETFC: Environmental Effects, Trans-
port, and Fate Committee
EF: Emission Factor
EFO: Equivalent Field Office
EFTC: European Fluorocarbon Technical
Committee
EGR: Exhaust Gas Recirculation
EH: Redox Potential
EHC: Environmental Health Committee
EHS: Extremely Hazardous Substance
El: Emissions Inventory
EIA: Environmental Impact Assessment.
Economic Impact Assessment
EIL: Environmental Impairment Liability
EIR: Endangerment Information Report;
Environmental Impact Report
EIS: Environmental Impact Statement;
Environmental Inventory System
EIS/AS: Emissions Inventory System/
Area Source
EIS/PS: Emissions Inventory System/
Point Source
-------
EKMA: Empirical Kinetic Modeling
Approach.
EL: Exposure Level
ELI: Environmental Law .Institute
ELR: Environmental Law Reporter
EM: Electromagnetic Conductivity
EMAP: Enviornmental Mapping and
Assessment Program
EMAS: Enforcement Management and
Accountability System
EMR: Environmental Management
Report
EMS: Enforcement Management System
EMSL: Environmental Monitoring
Support Systems Laboratory
EMTS: Environmental Monitoring
Testing Site; Exposure Monitoring Test
Site .
EnPA: Environmental Performance
Agreement ' ' -.
EO: Ethylene Oxide
EOC: Emergency Operating Center
EOF: Emergency Operations Facility
(RTF) .
EOF: End Of Pipe
EOT: Emergency Operations Team
EP: Earth Protectors; Environmental
Profile; End-use Product; Experimental
Product; Extraction Procedure.
EPAA: Environmental Programs
Assistance Act •
EPAAR: EPA Acquisition Regulations ,
EPCA: Energy Policy and Conservation
'Act
EPACASR: EPA Chemical Activities
Status Report
EPACT: Environmental Policy Act
EPCRA: Emergency Planning and
Community Right to Know Act
EPD: Emergency Planning District
EPI: Environmental Policy Institute
EPIC: Environmental Photographic •
•Interpretation Center , ." •--
EPNL: Effective Perceived Noise Level
EPRI: Electric Power Research Institute
EPTC: Extraction Procedure Toxicity
Characteristic
EQIP: Environmental Quality Incentives
Program •
ER: Ecosystem Restoration; Electrical
Resistivity
ERA:, Economic Regulatory Agency
ERAMS: Environmental Radiation
Ambient Monitoring System
ERG: Emergency Response Commission.
Emissions Reduction Credit, Environ-
mental Research Center
ERCS: Emergency Response Cleanup
Services "
ERDA: Energy Research and Develop-
ment Administration'
ERD&DAA: Environmental Research,
Development and Demonstration
Authorization Act .
ERL: Environmental Research Labora-
tory ' •. • • ,
ERNS: Emergency Response Notification
System , '
ERF: Enforcement Response Policy
ERT: Emergency Response Team
ERTAQ: ERT Air Quality Model
ES: Enforcement Strategy
ESA: Endangered Species Act. Environ-
mentally Sensitive Area
ESC: Endangered Species Committee
ESCA: Electron Spectroscopy for"
Chemical Analysis
ESCAP: Economic and Social Commis-
sion for Asia and the Pacific
ESECA: Energy Supply and Environ-
mental Coordination Act
ESH: Environmental Safety and Health
ESP: Electrostatic-Precipitators
ET: Emissions Trading
ETI: Environmental Technology Initia-
tive •
ETP: Emissions Trading Policy
ETS: Emissions Tracking System;
Environmental Tobacco Smoke *
ETV: Environmental Technology
Verification Program • ,
EUP: End-Use Product; Experimental
Use Permit
EWCC: Environmental Workforce
Coordinating Committee
EXAMS: Exposure Analysis Modeling
System • , :
ExEx: Expected Exceedance
FACA: Federal Advisory Committee Act
FAN: Fixed Account Number .
FATES: FIFRA and TSCA Enforcement
System . :
FBC: Fluidized Bed Combustion
FCC: Fluid Catalytic Converter ~
FCCC: Framework Convention on
Climate Change .
FCCU: Fluid Catalytic Cracking Unit
FCO: Federal Coordinating Officer (in '
disaster areas); Forms Control Officer
PDF: Fundamentally Different Factors
FDL: Final Determination Letter
FDO: Fee Determination Official
FE: Fugitive Emissions
FEDS: Federal Energy Data System
FEFx: Forced Expiratory Flow
FEIS: Fugitive Emissions Information
System
FEL: Frank Effect Level
FEPCA: Federal Environmental Pesticide
Control Act; enacted as amendments to
FIFRA. .
FERC: Federal Energy Regulatory
Commission
FES: Factor Evaluation System
FEV: Forced Expiratory Volume
FEV1: Forced Expiratory Volume—one
second; Front End Volatility Index
FF: Federal Facilities
FFAR: Fuel and Fuel Additiye Registra-
tion .
FFDCA: Federal Food, Drug, and
Cosmetic Act
FFF: Firm Financial Facility
FFFSG: Fossil-Fuel-Fired Steam Genera-
tor
FFIS: Federal Facilities Information
System . "
FFP:.Firm Fixed Price
FGD: Flue-Gas Desulfurization
FID: Flame lonization Detector
FIFRA: Federal Insecticide, Fungicide^
• and Rodenticide Act
FIM: Friable Insulation Material
FINDS: Facility Index System
FIP: Final Implementation Plan
FIPS: Federal Information Procedures.
System
FIT: Field Investigation Team
FLETC: Federal Law Enforcement
Training Center
FLM: Federal Land Manager
FLP: Flash Point
FLPMA: Federal Land Policy and
Management Act
F/M: Food to Microorganism Ratio
FMAP: Financial Management Assis- . ,
tance Project
FML: Flexible Membrane Liner'
55
-------
FMP: Facility Management Plan;
Financial Management Plan
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 Significant
Impact
FORAST: Forest Response to Anthropo-
genic Stress
FP: Fine Particulate
FPA: Federal Pesticide Act
FPAS: Foreign Purchase Acknowledge-
ment Statements
FPD: Flame Photometric Detector
FPEIS: Fine Particulate Emissions
Information System
FPM: Federal Personnel Manual
FPPA: Federal Pollution Prevention Act
FPR: Federal Procurement Regulation
FPRS: Federal Program Resources
Statement; Formal Planning and Sup-
porting System
FQPA: Food Quality Protection Act
FR: Federal Register. Final Rulemaking
FRA: Federal Register Act
FREDS: Flexible Regional Emissions
Data System
FRES: Forest Range Environmental
Study
FRM: Federal Reference Methods
FRN: Federal Register Notice. Final
Rulemaking Notice
FRS: Formal Reporting System
FS: Feasibility Study
FSA: Food Security Act
FSS: Facility Status Sheet; Federal
Supply Schedule
FTP: Federal Test Procedure (for motor
vehicles)
FTS: File Transfer Service
FITS: FIFRA/TSCA Tracking System
FUA: Fuel Use Act
FURS: Federal Underground Injection
Control Reporting System
FV.MP: Federal Visibility Monitoring
Program
FWCA: Fish and Wildlife Coordination
Act
56
FWPCA: Federal Water Pollution and
Control Act (aka CWA): Federal Water
Pollution and Control Administration
GAAP: Generally Accepted Accounting
Principles
GAC: Granular Activated Carbon
GACT: Granular Activated Carbon
Treatment
GAW: Global Atmospheric Watch
GCC: Global Climate Convention
GC/MS: Gas Chromatograph/ Mass
Spectograph
GCVTC: Grand Canyon Visibility
Transport Commission
GCWR: Gross Combination Weight
Rating
GDE: Generic Data Exemption
GEI: Geographic Enforcement Initiative
GEMI: Global Environmental Manage- '
ment Initiative
GEMS: Global Environmental Monitor-
ing System; Graphical Exposure Model-
ing System
GEP: Good Engineering Practice
GFF: Glass Fiber Filter
GFO: Grant Funding Order
GFP: Government-Furnished Property
GICS: Grant Information and Control
System
GIS: Geographic Information Systems;
Global Indexing System
GLC: Gas Liquid Chromatography
GLERL: Great Lakes Environmental
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/ Contrac-
tor-Operated
GOGO: Government-Owned/ Govern-
ment-Operated
GOP: General Operating Procedures
GOPO: Government-Owned/ Privately-
, Operated
GPAD: Gallons-per-acre per-day
GPG: Grams-per-Gallon
GPR: Ground-Penetrating Radar
GPS: Groundwater Protection Strategy
GR: Grab Radon Sampling
GRAS: Generally Recognized as Safe
GRCDA: Government Refuse Collection
and Disposal Association
GRGL: Groundwater Residue Guidance
Level
GT: Gas Turbine
GTN: Global Trend Network
GTR: Government Transportation
Request
GVP: Gasoline Vapor Pressure
GVW: Gross Vehicle Weight
GVWR: Gross Vehicle Weight Rating
GW: Grab Working-Level Sampling.
Groundwater
GWDR:. Ground Water Disinfedtion
Rule
GWM: Groundwater Monitoring
GWP: Global Warming Potential
GWPC: Ground Water Protetion Council
GWPS: Groundwater Protection Stan-
dard; Grpundwater Protection Strategy
H
HA: Health Advisory
HAD: Health Assessment Document
HAP: Hazardous Air Pollutant
HAPEMS: Hazardous Air Pollutant
Enforcement Management System
HAPPS: Hazardous Air Pollutant
Prioritization System
HATREMS: Hazardous and Trace
Emissions System
HAZMAT: Hazardous Materials-
HAZOP: Hazard and Operability Study
HBFC: Hydrobromofluorocarbon
HC: Hazardous Constituents; Hydrocar-
bon
HCCPD: Hexachlorocyclo-pentadiene
HCFC: Hydrochlorofluorocarbon
HCP: Hypothermal Coal Process
HDD: Heavy-Duty Diesel
HDDT: Heavy-duty Diesel Truck
HDDV: Heavy-Duty Diesel Vehicle
HDE: Heavy-Duty Engine
HDG: Heavy-Duty Gasoline-Powered
Vehicle
HDGT: Heavy-Duty Gasoline Truck
HDGV: Heavy-Duty Gasoline Vehicle
HDPE: High Density Polyethylene
-------
1 HOT: Highest Dose Tested in a study.
Trleavy-Duty Truck
HDV: Heavy-Duty Vehicle
HEAL: Human Exposure Assessment
Location '
HECC: House Energy^nd Commerce
Committee :' •
HEI: Health Effects Institute
HEM: Human Exposure Modeling
HEP A: Highly Efficient Particulate Air-
Filter •
HERS: Hyperion Energy Recovery
System
HFC: Hydrofluorocarbon
HHDDV: Heavy Heavy-Duty Diesel.
Vehicle
HHE: Human Health and the Environ-
ment
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 Transpor-
tation Act
HMTR: Hazardous Materials Transpor-,
tation Regulations
HOC: Halogenated Organic Carbons
HON: Hazardous Organic NESHAP
HOV: High-Occupancy Vehicle
HP: Horse Power
HPLC: High-Performance Liquid
Chromatography
HPMS: Highway Performance Monitor-
ing System
HPV: High Priority Violator
HQCDO: Headquarters Case Develop-
ment Officer
HRS: Hazardous Ranking System
HRUP: High-Risk Urban Problem
HSDB: Hazardous Substance Data Base
HSL: Hazardous Substance List
HSWA: Hazardous and Solid Waste
Amendments
HT: Hypothermally Treated
HTP: High Temperature and Pressure
HVAC: Heating, Ventilation, and Air-
Conditioning system ,
HVIO: High Volume Industrial Organics
HW: Hazardous Waste
HWDMS: Hazardous Waste Data
Management System .
HWGTF: Hazardous Waste Grouridwa-
ter Task Force; Hazardous Waste
Groundwater Test Facility
HWIR: Hazardous Waste Identification
Rule ' .. .
HWLT: Hazardous Waste Land Treat-
ment . -
• - i
-HWM: Hazardous Waste Management
HWRTF; Hazardous Waste Restrictions
Task Force ,.;
HWTC: Hazardous Waste Treatment
Council
I
I/A: Innovative/Alternative
IA: Interagency Agreement
IAAC: Interagency Assessment Advisory
Committee
IADN: Integrated Atmospheric Deposi-
tion Network
IAG: Interagency Agreement
IAP: Incentive Awards Program. Indoor'
Air Pollution
IAQ: Indoor Air Quality
IARC: International Agency for Research
on Cancer
IATDB: Interim Air Toxics Data Base
IBSIN: Innovations, in Building Sustain-
able Industries
IBT: Industrial Biotest Laboratory
1C: Internal Combustion
ICAIR: Interdisciplinary Planning and
Information Research • .
ICAP: Inductively Coupled Argon '
Plasma
- ICB: Information Collection Budget
ICBN: International Commission on the
Biological Effects of Noise
ICCP: International Climate Change
Partnership
ICE: Industrial Combustion Emissions
Model. Internal Combustion Engine
ICP: Inductively Coupled Plasma
ICR: Information Collection Request
ICRE: Ignitability, Corrosivity, Reactiv-
ity, Extraction \'
ICRP: International Commission on
Radiological Protection ',....
ICRU: International Commission of
Radiological Units and Measurements
ICS: Incident Command System.
Institute for Chemical Studies;
Intermittent Control Strategies,; Intermit-
tent Control System
ICWM: Institute for Chemical Waste
Management
IDLH: Immediately Dangerous to Life
• and Health
IEB: International Environment Bureau
' IEMP: Integrated Environmental
Management Project • .-.
IBS: "Institute for Environmental Studies
IFB: Invitation for Bid
IFCAM: Industrial Fuel Choice Analysis
Model • . .'
. IFCS: International Forum on Chemical.
Safety :
• IFIS: Industry File Information System
IFMS: Integrated Financial Management
System
IFPP: Industrial Fugitive Process
Particulate '
IGCC: Integrated Gasification Combined
.' Cycle
IGCI: Industrial Gas Cleaning Institute
IIS: Inflationary Impact Statement
IINERT: Ih-Place Inactivation and
Natural Restoration Technologies
IJC: International Joint Corrimissipn (on
Great Lakes)
I/M: Inspection/Maintenance
IMM: Intersection Midblock Model
IMPACT: Integrated Model of Plumes .
and Atmosphere in Complex Terrain
IMPROVE: Interagency Monitoring of
Protected Visual Environment
INPUFF: Gaussian Puff Dispersion
Model .
INT: Intermittent
IOB: Iron,Ore.Beneficiation
IOU: Input/Output Unit
IPCC: Intergovernmental Panel on
Climate Change
IPCS: International Program on Chemi-
cal Safety .
IP: Inhalable Particles
IPM: Inhalable Particulate Matter.
Integrated Pest Management
IPP: Implementation Planning Program.
Integrated Plotting Package; Inter-media
Priority Pollutant (document); Indepen- •
dent Powe'r Producer
IRG: Interagency Review Group
57
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IRLG: Interagency Regulatory Liaison
Group (Composed of EPA, CPSC, FDA,
and OSHA)
IRIS: Instructional Resources Informa-
tion System. Integrated Risk Information
System
IRM: Intermediate Remedial Measures
IRMC: Inter-Regulatory Risk Manage-
ment Council
IRP: Installation Restoration Program
IRPTC: International Register of Poten-
tially Toxic Chemicals
IRR: Institute of Resource Recovery
IRS: International Referral Systems
IS: Interim Status
ISAM: Indexed Sequential File Access
Method
ISC: Industrial Source Complex
ISCL: Interim Status Compliance Letter
ISCLT: Industrial Source Complex Long
Term Model
ISCST: Industrial Source Complex Short
Term Model
ISO: Interim Status Document
ISE: lon'Specific electrode
ISMAP: Indirect Source Model for Air
Pollution
ISO: International Organization for
Standardization
ISPF: (IBM) Interactive System
Productivity Facility
ISS: Interim Status Standards
ITC: Inovative Technology Council;
Interagency Testing Committee
ITRC: Interstate Technology Regulatory
Coordination
ITRD: Innovative Treatment
Remediation Demostration
IUP: Intended Use Plan
IUR: Inventory Update Rule
IWC: In-Stream Waste Concentration
IVVS: Ionizing Wet Scrubber
J
JAPCA: Journal of Air Pollution Control
Association
JCL: Job Control Language
JEC: Joint Economic Committee
JECFA: Joint Expert Committee of Food
Additives
JEIOG: Joint Emissions Inventory
Oversight Group
JLC: Justification for Limited Competi-
tion
JMPR: Joint Meeting on Pesticide
Residues
JNCP: Justification for Non-Competitive
Procurement
JOFOC: Justification for Other Than Full
and Open Competition
JPA: Joint Permitting Agreement
JSD: Jackson Structured Design
JSP: Jackson Structured Programming
JTU: Jackson Turbidity-Unit
LAA: Lead Agency Attorney
LADD: Lifetime Average Daily Dose;
Lowest Acceptable Daily Dose
LAER: Lowest Achievable Emission Rate
LAI: Laboratory Audit Inspection
LAMP: Lake Acidification Mitigation
Project
LC: Lethal Concentration. Liquid
Chromatography
LCA: Life Cycle Aassessment
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 Convention
LDCRS: Leachate Detection, Collection,
and Removal System
LDD: Light-Duty Diesel
LDDT: Light-Duty Diesel Truck
LDDV: Light-Duty Diesel Vehicle
LDGT: Light-Duty Gasoline Truck
LDIP: Laboratory Data Integrity Pro-
•gram
LDR: Land Disposal Restrictions
LDRTF: Land Disposal Restrictions Task
Force
LDS: Leak Detection System
LOT: Lowest Dose Tested. Light-Duty
Truck
LDV: Light-Duty Vehicle .
LEL: Lowest Effect Level. Lower Explo-
sive Limit
LEP: Laboratory Evaluation Program
LEPC: Local Emergency Planning
Committee
LERC: Local Emergency Response
Committee ,
LEV: Low Emissions Vehicle
LEG: Landfill Gas
LFL: Lower Flammability Limit
LGR: Local Governments Reimburse-
ment Program
LHDDV: Light Heavy-Duty Diesel
Vehicle
LI: Langelier Index
LIDAR: Light Detection and Ranging
LIMB: Limestone-Injection Multi-Stage
Burner
LLRW: Low Level Radioactive Waste
LMFBR: Liquid Metal Fast Breeder
Reactor
LMOP: Landfill-Methane Outreach
Program
LNAPL: Light Non-Aqueous Phase
Liquid
LOAEL: Lowest-Observed-Adverse-
Effect-Level
LOD: Limit of Detection
LQER: Lesser Quantity Emission Rates
LQG: Large Quantity Generator
LRTAP: Long Range Transboundary Air
Pollution
LUIS: Label Use Information System
M
MAC: Mobile Air Conditioner
MAPSIM: Mesoscale Air Pollution
Simulation Model
MATC: Maximum Acceptable Toxic
Concentration
MBAS: Methylene-Blue-Active Sub-
stances
MCL: Maximum Contaminant Level
MCLG: Maximum Contaminant Level
Goal
MDL: Method Detection Limit
MEC: Model Energy Code
MEI: Maximally (or most) Exposed
Individual
MEP: Multiple Extraction Procedure
MHDDV: Medium Heavy-Duty Diesel
Vehicle
MOBILE5A: Mobile Source Emission
Factor Model
MOE: Margin Of Exposure
58
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-. MaTgi-rv oi Safety
MP: Manufacturing-use Product;
Melting Point , ,
MPCA: Microbial Pest Control Agent
MPI: Maximum Permitted Intake
MPN: Maximum Possible Number
MPWC: Multiprocess Wet Cleaning -
MRF: Materials Recovery Facility
MRID: Master Record Identification
number
MRL: Maximum-Residue Limit (Pesti-
cide Tolerance)
MSW: Municipal Solid Waste
MTD: Maximum Tolerated Dose
MUP: Manufacturing-Use Product
MUTA: Mtitagenicity •
MWC: Machine Wet Cleaning
N
NAA: Nonattainment Area
NAAEC: North American Agreement on
Environmental Cooperation
NAAQS: National Ambient Air Quality
Standards ,
NACA: National Agricultural Chemicals
Association • '
' NACEPT: National Advisory Council for
Environmental Policy and Technology
NADP/NTN: National Atmospheric
Deposition Program/National Trends
Network
NAMS: National Air Monitoring
Stations
NAPAP: National Acid Precipitation
Assessment Program
NAPL: Non-Aqueous Phase Liquid
NAPS: National Air Pollution Surveil-
lance
NARA: National Agrichemical Retailers
Association . ,
NARSTO: North American Research
Strategy for Tropospheric Ozone
NAS: National Academy of Sciences
NASD A: National Association of State
Departments of Agriculture
NCAMP: National Coalition Against the
Misuse of Pesticides
NCEPI: National Center for Environ-
mental Publications and Information
NCWS: Npn-Community Water System
NEDS: National Emissions Data System
NEPI: National Environmental Policy
Institute
NEPPS: National Environmental
Performance Partnership System
NESHAP: National Emission Standard
for Hazardous Air Pollutants
NIEHS: National Institute for Environ-
mental Health Sciences
NET A: National Environmental .Training
Association " . • .
NFRAP: No Further Remedial Action
Planned
NICT: National Incident Coordination
Team
NIOSH: National Institute of Occupa-
tional Safety and Health
NIPDWR: National Interim Primary
Drinking Water Regulations .
NIS AC: National Industrial Security
Advisory Committee
NMHC: Ndnmethane Hydrocarbons
NMOC: Non-Methane Organic Compo-
nent • ' . . •
NMVOC: Non-methane Volatile Organic
Chemicals
NO: Nitric Oxide
NOA: Notice of Arrival -.
NOAA: National Oceanographic and
Atmospheric Agency,
NO AC: Nature of Action Code .
NOAEL: No Observable Adverse Effect
Level
NOEL: No Observable Effect Level
NOIC: Notice of Intent to Cancel
NOIS: Notice of Intent to Suspend
N2O: Nitrous Oxide
NOX: Nitrogen Oxides
NORM: Naturally Occurring Radioac-
tive Material
NPCA: National Pest Control Associa-'
tion
NPDES: National Pollutant Discharge ,
Elimination System
NPHAP:,National Pesticide Hazard
Assessment Program
NPIRS: National Pesticide Information
Retrieval System ,
NPTN: National Pesticide Telecommuni-
cations Network
NRD: Naural Resource Damage
NRDC: Natural Resources Defense
-Council ,
NSDWR: National Secondary Drinking
Water Regulations
NSEC: National System for Emergency
Coordination
NSEP: National System.for Emergency
Preparedness
NSPS: New Source Performance
Standards
NSR: New Source Review
NTI: National Toxics Inventory
NTIS: National Technical Information
Service
NTNCWS: Non-Transient Non-Commu-
nity Water System
NTP: National Toxicology Program
NTU: Nephlometric Turbidity Unit
o
O3: Ozone
•OCD: Offshore and Coastal Dispersion
OOP: Ozone-Depleting Potential
ODS: Ozone-Depleting Substances
OECD: Organization for Economic
Cooperation and Development
OF: Optional Form
OLTS: On Line Tracking System
O&M: Operations and Maintenance
ORM: Other Regulated Material
ORP: Oxidation-Reduction Potential
OTAG: Ozone Transport Assessment •,.
Group
OTC: Ozone Transport Commission
OTR: Ozone .Transport Region
P2: .Pollution Prevention
PAG: Pesticide Assignment Guidelines
PAH: Polynuclear Aromatic Hydrocar-
bons .••••••
PA1: Performance Audit Inspection
(CWA); Pure Active Ingredient com-
.pound
PAM: Pesticide Analytical Manual
PAMS: Photochemical Assessment
Monitoring Stations»
PAT: Permit Assistance Team (RCRA)
PATS: Pesticide Action Tracking System;
Pesticides Analytical Transport Solution •
Pb: Lead '.
PBA: Preliminary Benefit Analysis
(BEAD) .
PCA: Principle Component Analysis
PCS: Polychlorinated Biphenyl
PCE: Perchloroethylene
PCM: Phase Contrast Microscopy
59
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PCN: Policy Criteria Notice
PCO: Pest Control Operator
PCSD: President's Council on Sustain-
able Development
PDCI: Product Data Call-In
PFC: Perfluorated Carbon
PFCRA: Program Fraud Civil Remedies
Act
PHC: Principal Hazardous Constituent
PHI: Pre-Harvest Interval
PHSA: Public Health Service Act
PI: Preliminary Injunction. Program
Information
PIC: Products of Incomplete Combustion
PIGS: Pesticides in Groundwater
Strategy
PIMS: Pesticide Incident Monitoring
System
PIN: Pesticide Information Network;
Procurement Information Notice
PIP: Public Involvement Program
PIPQUIC: Program Integration Project
Queries Used in Interactive Command
PIRG: Public Interest Research Group
P1RT: Pretreatment Implementation
Review Task Force
PIT: Permit Improvement Team
PITS: Project Information Tracking
System
PLIRRA: Pollution Liability Insurance
and Risk Retention Act
PLM: Polarized Light Microscopy
PLUVUE: Plume Visibility Model
PM: Particulate Matter
PMAS: Photochemical Assessment
Monitoring Stations
PM2.5: Particulate Matter Smaller than
2.5 Micrometers in Diameter
PM10: Particulate Matter (nominally
10m and less)
PM15: Particulate Matter (nominally
15m and less)
PMEL: Pacific Marine Environmental
Laboratory
PMN: Premanufacture Notification
PMNF: Premanufacture Notification
Form
PMR: Pollutant Mass Rate;
Proportionate Mortality Ratio
PMRS: Performance Management and
Recognition System
PMS: Program Management System
PNA: Polynuclear Aromatic Hydrocar-
bons
PO: Project Officer
POC: Point Of Compliance
POE: Point Of Exposure
POGO: Privately-Owned/ Government-
Operated
POHC: Principal Organic Hazardous
Constituent
POI: Point Of Interception
POLREP: Pollution Report
POM: Particulate Organic Matter.
Polycyclic Organic Matter
POP: Persistent Organic Pollutant
POR: Program of Requirements
POTW: Publicly Owned Treatment
Works
POV: Privately Owned Vehicle
PP: Program Planning
PPA: Planned Program Accomplishment
PPB: Parts Per Billion
PPE: Personal Protective Equipment
PPG: Performance Partnership Grant
PPIC: Pesticide Programs Information
Center
PPIS: Pesticide Product Information
System; Pollution Prevention Incentives
for States
PPMAP: Power Planning Modeling
Application Procedure
PPM/PPB: Parts per million/ parts per
billion
PPSP: Power Plant Siting Program
PPT: Parts Per Trillion
PPTH: Parts Per Thousand
PQUA: Preliminary Quantitative Usage
Analysis
PR: Pesticide Regulation Notice; Pre-
liminary Review
PRA: Paperwork Reduction Act; Planned
Regulatory Action
PRATS: Pesticides Regulatory Action
Tracking System
PRC: Planning Research Corporation
PRI: Periodic Reinvestigation
PRM: Prevention Reference Manuals
PRN: Pesticide Registration Notice
PRP: Potentially Responsible Party
PRZM: Pesticide Root Zone Model
PS: Point Source
PS AM: Point Source Ambient Monitor-
ing
PSC: Program Site Coordinator
PSD: Prevention of Significant Deteriora-
tion
PSES: Pretreatment Standards for
Existing Sources •*
PSI: Pollutant Standards Index; Pounds
Per Square Inch; Pressure Per Square
Inch
PSIG: Pressure Per Square Inch Gauge
PSM: Point Source Monitoring
PSNS: Pretreatment Standards for New
Sources
PSU: Primary Sampling Unit
PTDIS: Single Stack Meteorological
Model in EPA UNAMAP Series
PTE: Potential to Emit
PTFE: Polytetrafluoroethylene (Teflon)
PTMAX: Single Stack Meteorological
Model in EPA UNAMAP series
PTPLU: Point Source Gaussian Diffusion
Model
PUC: Public Utility Commission
PV: Project Verification
PVC: PolyvinylChloride
PWB: Printed Wiring Board
PWS: Public Water Supply
PWSS: Public Water Supply System
Q
QAC: Quality Assurance Coordinator
QA/QC: Quality Assistance/ Quality
Control .
QAMIS: Quality Assurance Management
and Information System
QAO: Quality Assurance Officer
QAPP: Quality Assurance Program (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 Program
QL: Quantification Limit
QNCR: Quarterly Noncompliance
Report
QUA: Qualitative Use Assessment
QUIPE: Quarterly Update for Inspector
• in Pesticide Enforcement
60
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R
RA: Reasonable Alternative; Regional
Administrator; Regulatory Alternatives;
Regulatory Analysis; Remedial Action;
Resource Allocation; Risk Analysis; Risk
Assessment
RAATS: RCRA Administrate Action
Tracking System
RAG: Radiation Advisory Committee.
Raw Agricultural Commodity; Regional
Asbestos Coordinator. Response Action
Coordinator
RACM: Reasonably Available Control
Measures
RACT: Reasonably Available Control
Technology '
RAD: Radiation Adsorbed Dose (unit of
measurement of radiation absorbed by
humans) • '
RADM: Random Walk Advection and
Dispersion Model; Regional Acid
Deposition 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; Registra-
tion Assessment Panel; Remedial
Accomplishment Plan; 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
RBAC: Re-use Business Assistance
Center
RBC: Red Blood Cell
RC: Responsibility Center
.RCC: Radiation Coordinating Council
RCDO: Regional Case Development
Officer
RCO: Regional Compliance Officer
RCP: Research Centers Program
RCRA: Resource Conservation and
Recovery Act
RCRIS: Resource Conservation and
Recovery Information System
RD/RA: Remedial Design/ Remedial
Action
R&D: Research and Development
RD&D: Research, Development and
Demonstration i • ,
RDF: Refuse-Derived Fuel
rDNA: Recombinant DNA
RDU: Regional Decision Units
RDV: Reference Dose Values
RE: Reasonable Efforts; Reportable Event
REAP: Regional Enforcement Activities
Plan
RECLAIM: Regional Clean Air Initia-
tives Marker
RED: Reregistration Eligibility Decision
Document
RED A: Recycling Economic Develop-
ment Advocate
REE: Rare Earth Elements
REEP: Review of Environmental Effects
of Pollutants
ReFIT: Reinvention for Innovative
Technlogies ; '. •.
REI: Restricted Entry Interval
REM (Roentgen Equivalent Man)
REM/FIT: Remedial/Field Investigation
' Team _
REMS: RCRA Enforcement Management
System '
REP: Reasonable Efforts Program
REPS: Regional Emissions Projection
System
RESOLVE: Center for Environmental
Conflict Resolution
RF: Response Factor
RFA: Regulatory Flexibility Act
RFB: Request for Bid
RfC: Reference Concentration
RFD:'Reference Dose Values
RFI: Remedial Field Investigation
RFP: Reasonable Further Programs.
Request for Proposal
RHRS: Revised Hazard Ranking System
RI: Reconnaissance Inspection
RI: Remedial Investigation
RIA: Regulatory Impact Analysis;
Regulatory Impact Assessment
RIC: Radon Information Center
RICC: Retirement Information and
Counseling Center
RICO: Racketeer Influenced and Corrupt •
Organizations Act
•RI/FS: Remedial Information/ Feasibility
Study ' ~ '. • • ' r ' .
RIM: Regulatory Interpretation Memo-
randum
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 Maximum
Contaminant Level (this phrase being
discontinued in favor of MCLG).
RMDHS: Regional Model Data Han-
dling System , . ••
RMIS: Resources Management Informa-
tion System
RNA: Ribonucleic Acid •
ROADCHEM: Roadway Version that
Includes Chemical Reactions of BI, NQ2,
andO3
ROADWAY: A Model to Predict
Pollutant Concentrations Near a Road-
way
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: Rate of Progress; Regional Over-
sight Policy
ROPA: Record Of Procurement Action
ROSA: Regional Ozone Study Area
RP: Radon Progeny Integrated Sampling.
Respirable Particulates. 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; Requi-
site Remedial Technology ,
RS: Registration Standard
RSCC: Regional Sample Control Center
. RSD: Risk-Specific Dose
RSE: Removal Site Evaluation
RTCM: Reasonable Transportation
Control Measure .
RTDF: Remediation Technologies
Development Forum ,
RTDM: Rough Terrain Diffusion Model
RTECS: Registry of Toxic Effects of
Chemical Substances
61
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RTM: Regional Transport Model
RTF: Research Triangle Park
RUP: Restricted Use Pesticide
RVP: Reid Vapor Pressure
RWC: Residential Wood Combustion
S&A: Sampling and Analysis. Surveil-
lance and Analysis
SAB: Science Advisory Board
SAC: Suspended and Cancelled Pesti-
cides
SAEWG: Standing Air Emissions Work
Group
SAIC: Special-Agents-In-Charge
' SAIP: Systems Acquisition and Imple-
mentation Program
SAMI: Southern Appalachian Mountains
Initiative
SAMWG: Standing Air Monitoring
Work Group
SANE: Sulfur and Nitrogen Emissions
SANSS: Structure and Nomenclature
Search System
SAP: Scientific Advisory Panel
SAR: Start Action Request. Structural
Activity Relationship (of a qualitative
assessment)
SARA: Superfund Amendments and
Reauthorization Act of 1986
SAROAD: Storage and Retrieval Of
Aerometric Data
SAS: Special Analytical Service. Statisti-
cal Analysis System
SASS: Source Assessment Sampling
System
SAV: Submerged Aquatic Vegetation
SBC: Single Breath Cannister
SBS: Sick Building Syndrome
SC: Sierra Club
SCAP: Superfund Consolidated Accom-
plishments Plan
SCBA: Self-Contained Breathing
Apparatus
SCC: Source Classification Code
SCD/SWDC: Soil or Soil and Water
Conservation District
SCFM: Standard Cubic Feet Per Minute
SCLDF: Sierra Club Legal Defense Fund
SCR: Selective Catalytic Reduction
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 Oxidation
SDC: Systems Decision Plan
SDWA: Safe Drinking Water Act
SDWIS: Safe Driking Water Information
System -
SEA: State Enforcement Agreement
SEA: State/EPA Agreement
SEAM: Surface, Environment, and
Mining
SEAS: Strategic Environmental Assess-
ment System
SEDS: State Energy Data System
SEGIP: State Environmental Goals and
Improvement Project
SEIA: Socioeconomic Impact Analysis
SEM: Standard Error of the Means
SEP: Standard Evaluation Procedures
SEP: Supplementary Environmental
Project
SEPWC: Senate Environment and Public
Works Committee
SERC: State Emergency Planning
Commission
SES: Secondary Emissions Standard
SET AC: Society for Environmental
Toxicology and Chemistry
SETS: Site Enforcement Tracking 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. Surveillance Index. Spark
Ignition
SIC: Standard Industrial Classification-
SICEA: Steel Industry Compliance
Extension Act
SIMS: Secondary Ion-Mass Spectrometry
SIP: State Implementation Plan
SITE: Superfund Innovative Technology
Evaluation
' SLAMS: State/Local Air Monitoring
Station
SLN: Special Local Need
SLSM: Simple Line Source Model
SMART: Simple Maintenance of ARTS
SMCL: Secondary Maximum Contami-
nant Level
SMCRA: Surface Mining Control and
Reclamation Act
SME: Subject Matter Expert
SMO: Sample Management Office
SMOA: Superfund Memorandum of ,
Agreement
SMP: State Management Plan
SMR: Standardized Mortality Ratio
SMSA: Standard Metropolitan Statistical
Area
SNA: System Network Architecture
SNAAQS: Secondary National Ambient
Air Quality Standards
SNAP: Significant New Alternatives
Project; Significant Noncompliance
Action Program
SNARL: Suggested No Adverse Re-
sponse Level
SNC: Significant Noncompliers
SNUR: Significant New Use Rule
SO2: Sulfur Dioxide
SOC: Synthetic Organic Chemicals
SOCMI: Synthetic Organic Chemicals
Manufacturing Industry
SOFC: Solid Oxide Fuel Cell
SOTDAT: Source Test Data
SOW: Scope Of Work
SPAR: Status of Permit Application
Report
SPCC: Spill Prevention, Containment,
and Countermeasure
SPE: Secondary Particulate Emissions
SPF: Structured Programming Facility
SPI: Strategic Planning Initiative
SPLMD: Soil-pore Liquid Monitoring
Device
SPMS: Strategic Planning and Manage-
ment System; Special Purpose Moni-
toring Stations
SPOC: Single Point Of Contact
SPS: State Permit System
SPSS: Statistical Package for the Social
Sciences
62
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SPUR-. Software Package for Unique
Reports
SQBE: Small Quantity Burner Exemp-
tion
SQG: Small Quantity Generator;
Sediment Quality Guidelines
SR: Special Review
SRAP: Superfund Remedial Accomplish-
ment Plan
SRC: Solvent-Refined Coal
SRF: State Revolving Fund
SRM: Standard Reference Method
SRP; Special Review Procedure
SRR: Second Round Review. Submission
Review Record
SRTS: Service Request Tracking System
SS: Settleable Solids. Superfund Sur-
charge. Suspended Solids
SSA: Sole Source Aquifer
SSAC: Soil Site Assimilated Capacity
SSC: State Superfund Contracts
SSD: Standards Support Document
SSEIS: Standard Support and Environ-
mental Impact Sta'tementt; Stationary
Source Emissions and Inventory System.
SSI: Size Selective Inlet
SSMS: Spark Source Mass Spectrometry >•' •
SSO: Sanitary Sewer Overflow; Source
Selection Official
SSRP: Source Reduction Review Project
SSTS: Section Seven Tracking System
SSURO: Stop Sale, Use and Removal
Order
"STALAPCO: State and Local Air-
Pollution Control Officials
STAPPA: State and Territorial Air
Pollution
STAR: Stability Wind Rose. State Acid
Rain Projects ,
STARS: Strategic Targeted 'Activities for •
Results System
STEL: Short Term Exposure Limit
S JEM: Scanning Transmission-Electron
Microscope *
STN: Scientific and Technical Informa-
tion Network
STORET: Storage and Retrieval of
Water-Related Data
STP: Sewage Treatment Plant. Standard
Temperature' and Pressure
STTF: Small Town Task Force (EPA)
SUP: Standard Unit of Processing
SURE: Sulfate Regional Experiment
Program
SV: Sampling Visit; Significant Violafer
SW: Slow Wave
SWAP: Source Water Assesment
Program .
SWARF: Waste from Metal Grinding
Process
SWC: Settlement With Conditions
SWDA: Solid Waste Disposal Act
SWIE: Southern Waste Information
Exchange
SWMU: Solid Waste Management Unit
SWPA: Source Water Protection Area
SWQPPP: Source, Water Quality Protec-
tion Partnership Petitions
SWTR:" Surf ace Water Treatment Rule
SYSOP: Systems Operator
TAD: Technical Asssistance Document
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 Program
TAPDS: Toxic Air Pollutant Data System
TAS: Tolerance Assessment System
TBT: Tributyltin
TC: Target Concentration. Technical
Center. Toxicity Characteristics. Toxic
Concentration:
TCDD: Dioxin (Tetrachlorodibenzo-p-
dioxin) ,
TCDF: Tetrachlorodi-benzofurans
TCE: Trichloroethylene
TCP: Total Chlorine Free .
TCLP: Total Concentrate Leachate
Procedure. Toxicity Characteristic •
Leachate Procedure
TCM: Transportation Control Measure
TCP: Transportation Control Plan;
Trichlorpprop ane;
TCRI: Toxic Chemical Release Inventory
TD: Toxic Dose •
TDS: Total Dissolved Solids
TEAM: Total Exposure Assessment
Model
TEC: Technical Evaluation Committee
TED: Turtle Excluder Devices
TEG: Tetraethylehe Glycpl
TEGD: Technical Enforcement Guidance
Document
TEL: Tetraethyl Lead
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
TGO: Total Gross Output
TG AI: Technical Grade of the Active
Ingredient
TCP: Technical Grade Product
THC: Total Hydrocarbons
THM: Trihalomethane
TI: Temporary Intermittent; Therapeutic
Index • •
TIBL: Thermal Internal Boundary Layer
TIC: Technical Information Coordinator.
Tentatively Identified Compounds
TIM: Technical Information Manager
TIP: Technical Information Package;
Transportation Improvement Program
TIS: Tolerance Index System
TISE: Take It Somewhere Else
TITC: Toxic Substance Control Act
Interagency Testing Committee
TLV: Threshold Limit Value ,
TLV-C: TLV-Ceiling
TLV-STEL: TLV-Short Term Exposure
Limit
TLV-TWA: TLV-Time Weighted Aver-
age - • .\
TMDL: Total Maximum Daily Limit;
Total Maximum Daily Load
TMRC: Theoretical Maximum Residue
Contribution _
TNCWS: Transient Non-Community
: Water System
TNT: Trinitrotoluene
TO: Task Order
TOA: Trace Organic Analysis
TOC: Total Organic Carbon/ Compound
TOX: f etradichloroxylene
TP: Technical Product; Total Particulates
TPC: Testing Priorities Committee
TPI: Technical Proposal Instructions
TPQ: Threshold Planning Quantity
63
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TPSIS: Transportation Planning Support
Information System
TPTH: Triphenyltinhydroxide
TPY: Tons Per Year
TQM: Total Quality Management
T-R: Transformer-Rectifier
TRC: Technical Review Committee
TRD: Technical Review Document
TRI: Toxic Release Inventory
TRIP: Toxic Release Inventory Program
TRIS: Toxic Chemical Release Inventory
System
TRLN: Triangle Research Library
Network
TRO: Temporary Restraining Order
TSA: Technical Systems Audit
TSCA: Toxic Substances Control Act
TSCATS: TSCA Test Submissions
Database
TSCC: Toxic Substances Coordinating
Committee
TSD: Technical Support Document
TSDF: Treatment, Storage, and Disposal
Facility
TSDG: Toxic Substances Dialogue
Group
TSI: Thermal System Insulation
TSM: Transportation System Manage-
ment
TSO: Time Sharing Option
TSP: Total Suspended Particulates
TSS: Total Suspended (non-filterable)
Solids
TTFA: Target Transformation Factor
Analysis
TTHM: Total Trihalomethane
TTN: Technology Transfer Network
TTO: Total Toxic Organics
TTY: Teletypewriter
TVA: Tennessee Valley Authority
TVOC: Total Volatile Organic Com-
pounds
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 Precipitation Study
Program
UAQI: Uniform Air Quality Index
UARG: Utility Air Regulatory Group
UCC: Ultra Clean Coal
UCCI: Urea-Formaldehyde Fo'am
Insulation
UCL: Upper Control Limit
UDMH: Unsymmetrical Dimethyl
Hydrazine
UEL: Upper Explosive Limit
UF: Uncertainty Factor
UFL: Upper Flammability Limit
ug/m3: Microgrms Per Cubic Meter
UIC: Underground Injection Control
ULEV: Ultra Low Emission Vehicles
UMTRCA: Uranium Mill Tailings
Radiation Control Act
UNAMAP: Users' Network for Applied
Modeling of Air Pollution
UNECE: United Nations Economic
Commission for Europe
UNEP: United Nations Environment
Program
USC: Unified Soil Classification
USDA: United States Department of
Agriculture
USDW: Underground Sources of
Drinking Water
USFS: United States Forest Service
FS:
UST: Underground Storage Tank
UTM: Universal Transverse Mercator
UTP: Urban Transportation Planning
UV: Ultraviolet
UVA, UVB, UVC: Ultraviolet Radiation
Bands
UZM: Unsaturated Zone Monitoring
V
VALLEY: Meteorological Model to
Calculate Concentrations on Elevated
Terrain
VCM: Vinyl Chloride Monomer
VCP: Voluntary Cleanup Program
VE: Visual Emissions
VEO: Visible Emission Observation
VHS: Vertical and Horizontal Spread
Model
VHT: Vehicle-Hours of Travel
VISTTA: Visibility Impairment from
Sulfur Transformation and Transport in
the Atmosphere
VKT: Vehicle Kilometers Traveled
VMT: Vehicle Miles Traveled
VOC: Volatile Organic Compounds
VOS: Vehicle Operating Survey
VOST: Volatile Organic Sampling Train
VP: Vapor Pressure
VSD: Virtually Safe Dose
VSI: Visual Site Inspection
VSS: Volatile Suspended Solids
w
WA: Work Assignment
WADTF: Western Atmospheric Deposi-
tion Task Force
WAP: Waste Analysis Plan
WAVE: Water Alliances for Environmen-
tal Efficiency
WB: Wet Bulb
WCED: World Commission on Environ-
ment and Development
WDROP: Distribution Register of
Organic Pollutants in Water
WENDB: Water Enforcement National
Data Base
WERL: Water Engineering Research
Laboratory
WET: Whole Effluent Toxicity test
WHO: World Health Organization
WHP: Wellhead Protection Program
WHPA: Wellhead Protection Area
WHWT: Water and Hazardous Waste
Team
WICEM: World Industry Conference on
Environmental Management
WL: Warning Letter; Working Level
(radon measurement)
WLA/TMDL: Wasteload Allocation/
Total Maximum Daily Load
WLM: Working Level Month's
WMO: World Meteorological Organiza-
tion
WP: Wettable Powder
WPCF: Water Pollution Control Federa-
tion
WQS: Water Quality Standard
WRC: Water Resources Council
WRDA: Water Resources Development
Act
WRI: World Resources Institute
64
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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 Wastewater
Equipment Manufacturers Association
WWF: World Wildlife Fund
WWTP: Wastewater Treatment Plant
WWTU: 'Wastewater Treatment Unit
ZEV: Zero Emissions Vehicle
ZHE: Zero Headspace Extractor
ZOI:"Zone Of Incorporation
ZRL: Zero Risk Level '
•&U.S. GOVERNMENT PRINTING OFFICE: 1998 -415-003/60612
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