United States           Office of            August 1988
                 Environmental Protection     Public Affairs (A-107)       OPA-87-017
                 Agency              Washington DC 20460
v>EPA         Glossary of
                 Environmental Terms
                 and Acronym  List
                             U.S. Environmental Protection Agency
                             Region 5, Library (PI.-12J)
                             77 West Jackson Boulevard, 12th Floor
                             Ct.icago, IL 60604-3590

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Introduction
This glossary of environmental terms and acronym list replaces "Common Environmental
Terms," published by the Environmental Protection Agency in 1974 and revised in 1978. It is
designed to give the user an explanation of the more commonly used environmental terms
appearing in EPA publications, news releases and other Agency documents available to the
general public, students, the news media, and Agency employees. The terms and definitions
in this publication were selected to give the user a general sense of what a term or phrase
means in relatively non-technical language, although it was obviously necessary to use some
scientific terminology.
  The terms selected for inclusion came from previously published lists, internal glossaries
produced by various programs, and specific suggestions made by many Agency programs
and offices. The chemicals and pesticides selected for inclusion were those most frequently
referred to in Agency publications or which are the subject of major EPA regulatory or
program activities.
  Definitions or information about substances or program activities not included in this
glossary may be found in EPA libraries or scientific/technical reference documents or may be
obtained from the various program offices.
  The definitions do not constitute the  Agency's official  use of terms and phrases for
regulatory purposes. Nothing in this document should be construed to in any way alter or
supplant any other federal document. Official terminology may be found in the laws and
related regulations as published in such sources as the Congressional Record and the Federal
Register.
  Users with suggestions for future editions should write to the Publications Division, Office
of Public Affairs, A-107, USEPA Washington DC, 20460.

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Abatement: Reducing the degree or intensity of, or eliminating, pollution.
Abandoned Well: A well whose use has been permanently discontinued or
which is in a state of disrepair such that it cannot be used for its intended
purpose.
ABEL: EPA's computer mode! for analyzing a violator's ability to pay a civil
penalty.
Absorption: The passage of one substance into or through another; e.g., an
operation in which one or more soluble components  of a gas mixture are
dissolved in a liquid.
Accelerator: In radiation science, a device  that speeds up charged particles
such as electrons or protons.
Accident Site. The location of an unexpected 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 organ-
ism to changes in its environment.
Acetylcholine: A substance in the  human body having important
neurotransmitter effects on various internal systems, often used as a broncho-
constrictor
Acid  Deposition: A complex chemical and atmospheric phenomenon that
occurs when emissions of sulfur and nitrogen compounds and other sub-
stances are transformed by chemical processes in the atmosphere, often far
from the original sources, and then deposited on earth in either a 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 Rain: (See. acid deposition)
Action Levels. 1. Regulatory levels 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
"tolerances" 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 environment high enough
to warrant action or trigger a response under SARA and the National Oil and
Hazardous Substances Contingency Plan The term can be used similarly in
other regulatory programs  (See. tolerances.)
Activated Carbon: A highly adsorbent form of carbon used to remove odors
and toxic substances from liquid or gaseous emissions. In waste treatment it is
used to remove dissolved organic matter from waste water  It is also used m
motor vehicle evaporative control systems
Activated Sludge:  Sludge that results when primary effluent is mixed with
bacteria-laden sludge and then agitated and aerated  to promote biological
treatment This speeds breakdown of organic matter in raw sewage undergo-
ing secondary waste treatment
Active Ingredient: In any pesticide product, the component  which kills, or
otherwise controls, target pests Pesticides are regulated primarily on the basis
of active ingredients
Acute Exposure: A single exposure to a toxic substance which results in severe
biological harm or death  Acute exposures are usually characterized as lasting
no longer than a day.
Acute Toxicity: The ability of a substance to cause poisonous effects resulting
in severe biological harm or death soon after a single exposure or dose  Also,
any severe poisonous effect resulting from a single short-term exposure to a
toxic substance. (See chronic toxicity, toxicity.)
Adaptation: Changes in an organism's structure or habit that help it adjust to
its surroundings
Add-on Control Device: An air pollution control device  such as carbon adsor-
ber or incinerator which reduces the pollution in an exhaust gas. The control
device usually does not affect the process being controlled and thus is "add-
on" technology as opposed to a scheme to control pollution through making
some  alteration to the basic process
Adhesion: Molecular attraction which holds the surfaces of two substances in
contact.
Administrative Order:  A legal  document signed by  EPA  directing an in-
dividual, 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 administra-
ti\ e complaint whereby the respondent is ordered to pay a penalty for viola-
tions 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 require-
ments related to the promulgation of regulations.
Adsorption: 1. Adhesion of molecules of gas, liquid, or dissolved solids to a
surface. 2. An advanced method of treating wastes in which activated carbon
removes organic matter from wastewater.
Adulterants: Chemical impurities or substances that by law do not belong in a
food, or in a pesticide.
Advanced  Waste Water 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 nitrogen and a high percentage
of suspended  solids. (See primary, secondary treatment.)
Advisory: A non-regulatory document that communicates risk information to
persons who may have to make risk management decisions.
Aeration: A process which promotes biological degradation of organic 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. Types of aerobic processes include extended  aera-
tion, trickling filtration, and rotating biological contactors
Aerosol: A suspension of liquid or solid particles in a gas.
Afterburner: In incinerator technology, a burner located so that the combus-
tion gases are made to pass through its flame in order to remove smoke and
odors. It may be attached to or be separated from the incinerator proper.
Agent Orange: A toxic herbicide and defoliant which was used in the Vietnam
conflict.  It contains 2,4,5-trichlorophenoxyacitic  acid (2,4,5-T) and 2-4 di-
chlorophenoxyacetic acid (2,4-D) with trace amounts  of dioxin.
Agglomeration: The process by which precipitation particles grow larger by
collision or contact with cloud particles or other precipitation particles.
Agglutination: The process of uniting solid particles coated with a thin layer of
adhesive material or of arresting solid particles by impact on a surface coated
with an adhesive
Agricultural Pollution: The liquid and solid wastes from farming, including:
runoff and leaching of pesticides  and  fertilizers; erosion and dust from plo-
wing; animal manure and carcasses, crop residues, and debris.
Airborne Particulates: Total suspended particulate matter found in the atmos-
phere as solid particles or liquid droplets. Chemical composition of particu-
lates vanes widely, depending on location and time of year. Airborne particu-
lates include: windblown dust, emissions from industrial processes, smoke
from the burning of wood and coal, and the exhaust of motor vehicles.
Airborne Release: Release of any chemical into the air
Air Changes Per Hour (ACH): The movement of a volume of air in a given
period of time, if a house has one air change per hour, it means that all of the air
in the  house will be replaced in a one-hour period
Air Contaminant: Any particulate matter, gas, or  combination thereof, other
than water vapor or natural air. (See. air pollutant.)
Air Curtain: A method of containing oil spills. Air bubbling through a per-
forated 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 Mass:  A widespread body of air that gains certain  meteorological or
polluted  characteristics—e.g., a heat inversion  or smogginess—while set in
one location. The characteristics can change as it moves away.
Air Monitoring: (See: monitoring)
Air Pollutant: Any substance in air which could, if in high enough concentra-
tion, harm man, other animals, vegetation, or material  Pollutants  may in-
clude almost any natural or artificial composition of matter capable of being
airborne. They may be in the form of solid particles, liquid droplets, gases, or
in combinations of these forms. Generally, they fall into two main groups (1)
those emitted directly from identifiable sources and (2) those produced in the
air by interaction between two or more primary pollutants, or by reaction with
normal atmospheric constituents, with or without photoactivahon Exclusive
of pollen, fog.  and dust, which are of natural  origin, about 100 contaminants

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have been identified and fall into the following categories:  solids, sulfur
compounds, volatile organic chemicals, nitrogen compounds, oxygen com-
pounds, halogen compounds, radioactive compounds, and odors.
Air Pollution: The presence of contaminant or pollutant substances in th^air
that do not disperse properly and interfere with human health or welfare, br
produce other harmful environmental effects.
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, pollution.)
Air Quality  Control Region:  An area—designated by the  federal
government—in which communities share a common air pollution problem.
Sometimes several states are involved.
Air Quality Criteria: The levels of pollution and lengths of exposure above
which adverse health and welfare effects may occur.
Air Quality Standards: The level of pollutants prescribed by regulations that
may not be exceeded during a specified time in a defined area.
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 made from
ethyl isocyanate.
Algae: Simple rootless plants that grow in sunlit waters in relative proportion
to the amounts of nutrients available. They can affect water quality adversely
by lowering the dissolved oxygen in the water. They are food for fish and small
aquatic animals.
Algal Blooms: Sudden spurts  of algal  growth, which can affect water quality
adversely and indicate potentially hazardous changes in local water chemis-
try.
Alpha Particle: A positively charged particle composed of 2 neutrons and 2
protons released by some atoms undergoing radioactive decay. The particle is
identical to the nucleus of a helium atom.
Alternate Method: Any method of sampling and analyzing for an air pollutant
which is not a reference or equivalent method but which has been demon-
strated in specific cases to EPA's satisfaction to produce results adequate for
compliance..
Ambient Air: Any unconfined portion of the atmosphere: open air, surround-
ing air.
Ambient  Air  Quality Standards: (See:  Criteria Pollutants and National
Ambient Air Quality Standards)
Anadromous: Fish that spend their adult life in the sea but swim upriver to
fresh-water spawning grounds to reproduce.
Anaerobic: A life or process that occurs in, or is not destroyed by,  the absence
of oxygen.
Antagonism: The  interaction of two chemicals having an  opposing,  or
neutralizing effect on each other, or—given some specific biological effect—a
chemical interaction that appears to have an opposing or neutralizing effect
over what might otherwise be expected.
Antarctic "Ozone Hole": Refers to the seasonal depletion of ozone in a large
area over Antarctica.
Antibodies: Proteins produced in the body by immune system cells in re-
sponse to  antigens, and capable of combining with antigens.
Anti-Degradation Clause: Part of federal air quality and water quality require-
ments prohibiting  deterioration where pollution levels are above the legal
limit.
Antigen: A substance that causes production of antibodies when introduced
into animal or human tissue.
Aquifer: An underground geological formation, or group of formations, con-
taining usable  amounts of groundwater that can supply wells and springs.
Arbitration: A process for the resolution of disputes. Decisions are made by an
impartial arbitrator selected by the parties.  These decisions are usually legally
binding. (See:  mediation.)
Area of Review: In the  UIC program,  the area surrounding an injection well
that is reviewed during the permitting process to determine whether the
injection operation will induce flow between aquifers:
Area Source: Any small source of non-natural air pollution that is released
over a relatively small area but which cannot be classified as a point source.
Such sources may include vehicles and other small fuel combustion engines.
Asbestosis: A disease associated with chronic exposure to and inhalation of
asbestos fibers. The disease makes breathing progressively more difficult and
can lead to death.
Asbestos: A mineral fiber  that can pollute air or water and cause cancer or
asbestosis when inhaled. EPA has banned or severely restricted its use in
manufacturing and construction.
Ash: The mineral content of a product remaining after complete combustion.
A-Scale Sound Level: A measurement of sound approximating the sensitivity
of the human ear,  used to note the intensity  or annoyance of sounds.
Assimilation: The  ability of a body of water to  purify itself of pollutants.
Atmosphere [an]:  A standard unit  of pressure representing the pressure
exerted by a 29.92-inch column of mercury at sea level at 45' latitude and equal
to 1000 grams per square centimeter, (the) The whole mass of air surrounding
the earth, composed largely of oxygen and nitrogen.
Atomize: To divide a liquid into extremely minute particles, either by impact
with a jet of steam or compressed air, or by passage through some mechanical
device.
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
overtime, through adsorption, degradation, dilution, and/or transformation.
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 A contributing
factor in air pollution, as with dust.
Autotrophic: An organism that produces food  from inorganic substances.


B
Background Level: In air pollution control, the concentration of air pollutants
in a definite area during a fixed period of time prior to the starting up or on the
stoppage of a source of emission under control  In toxic substances monitor-
ing, the average presence in the environment, originally referring to naturally
occurring phenomena.
BACT—Best Available Control Technology:  A  emission limitation based on
the maximum degree of emission reduction which (considering energy, en-
vironmental, and economic impacts and other costs) is achievable through
application of production  processes and available methods, systems, and
techniques. In  no event does  BACT 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
emissions sources in attainment areas and applies to each regulated pollutant.
Bacteria: (Singular: bacterium) Microscopic living organisms which can aid in
pollution control by consuming or breaking down organic matter in sewage, or
by similarly acting on oil spills or other water pollutants. Bacteria in soil, water
or air can also cause human,  animal and plant health problems.
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 microns in diameter) parti-
cles. This device operates  in a way  similar to the bag of  an electric vacuum
cleaner, passing the air and smaller particulate  matter, while entrapping the
larger particulates.
Baling: Compacting solid  waste into blocks  to reduce volume and simplify
handling.
Ballistic Separator: A machine that sorts organic from inorganic matter for
composting.
Band Application: In pesticides, the spreading of chemicals over, or next to,
each row of plants in a field.
Banking: A system for recording qualified air emission reductions for later use
in bubble, offset, or netting transactions. (See: emissions trading.)
Bar Screen: In wastewater treatment, a device  used to remove large solids.

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 atrier Coating(s): A layer of a material that acts to obstruct or prevent passage
 if something through a surface that is to be protected, e.g. grout, caulk, or
 wious sealing compounds; sometimes used with polyurethane membranes
 o prevent corrosion or oxidation of metal surfaces, chemical impacts  on
 various materials, or,  for example,  to prevent soil-gas-borne radon from
 noving through walls, cracks, or joints in a house
 Jasal Application: In pesticides, the application of a chemical on plant stems
 jr tree trunks just above the  soil line
 JEN: EPA's computer model for analyzing a violator's economic gain from not
 :omplying with  the law
 Jenthic Organism (Benthos): A form of aquatic plant or animal  life that is
 ound on or near the bottom  of a stream, lake or ocean
 Senthic Region: The bottom layer of a body of water
 Jeryllium: An airborne metal that can be hazardous to human health when
 nhaled. It is discharged by machine shops, ceramic and propellant plants, and
 oundnes
 Seta Particle: An elementary particle emitted by radioactive decay, that may
 •ause skin burns. It is  halted  by a thin  sheet of papei
Bioaccumulative: Substances  that increase in  concentration in living organ-
isms (that are very slowly metabolized or excreted) as they breathe  con-
taminated air, drink contaminated water, or eat contaminated food (See
biological magnification.)
Bioassay: Using living organisms to measure the effect of a substance, factor,
or condition by comparing before-and-after data Term is often used to mean
cancer bioassays
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
Biodegradable: The ability to break down or decompose rapidly under natural
conditions and processes
Biological Control: In pest control, the use of animals and organisms that eat
or otherwise kill or out-compete pests
Biological Magnification: Refers to the process whereby certain substances
such as pesticides or heavy metals move up the food chain, work their way
into a river or  lake 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 (Seej
bioaccumulative )
Biological Oxidation:  The way  bacteria and  microorganisms feed on 'and
decompose complex organic  materials. Used in self-purification of water
bodies and in  activated sludge wastewater treatment
Biological Treatment: A treatment technology that uses bacteria to consume
waste  This treatment breaks  down organic materials
Biomass: All of the living material in  a gnen area, often refers to vegetation.
Also called "biota".
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
Biosphere: The portion ot Earth and  its atmosphere that can support life
Biostabilizer:  A machine that  converts solid waste into compost by grinding
and aeration
Biota: (See biomass )
Biotechnology: Techniques that use living organisms or parts of organisms to
produce  a variety of products  \from medicines to industrial enzymes) to
improve plants or animals or to develop microorgame -ris for specific uses such
as removing toxics from bodies  of water, or as pesticides.
Biotic Community: A naturally  occurring assemblage of plants and animals
that live  in the same environment and  are mutually sustaining  and inter-
dependent.
Black Lung: A disease of the lungs caused by habitual inhalation of  coal dust.
Blackwater: Water that contains animal, human, or food wastes
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
Bog: A type of wetland  that accumulates appreciable peat deposits. Bogs
depend primarily on precipitation for their water source, are usually acidic and
rich in plant residue with a conspicuous mat of living green moss.
 Boom: 1. A floating device used to contain oil on a body of water. 2. A p>eco e.f
 equipment used to apply pesticides from ground equipment such as a tractor
 or truck (See. sonic boom )
 Botanical Pesticide: A pesticide whose active ingredient is a plant produced
 chemical such as nicotine or strychnine
 Bottle Bill: Proposed or enacted  legislation which  requires a returnable
 deposit  on beer  or soda containers and provides for retail store or ether
 redemption centers. Such legislation is designed to discourage use of thi'iw-
 away containers.
 Bottom Land Hardwoods: Forested freshwater wetlands adjacent to ri\ e-\ .p
 the southeastern United States They are especially valuable for wildlife bi f^n
 ing and  nesting and habitat areas
 Brackish Water: A mixture of fresh and salt water
 Broadcast Application: In pesticides, the spreading of chemicals over an enMit
 area.
 Bubble:  A system under which existing emissions sources can propose jX r
 nate means to comply with a set of emissions limitations;  under the bi'!"  :,
 concept, sources can control more than required at one emission point » ! ere
 control costs are relatively low in return for a comparable relaxation of coi "\ ;s
 at a  second emission point where costs are higher
 Bubble Policy: (See' emissions trading )
 Buffer Strips: Strips of grass or other erosion-resisting vegetation betwei T > i
 below cultivated strips or fields.
 Burial Ground (Graveyard): A disposal site for  radioactive waste mater,-. --
 that uses earth or water as a shield
 By-product: Material, other than the principal product, that is generated
 consequence of an industrial process.
Cadmium (CD): A heavy metal element that accumulates in the environr it  • •.
Cancellation:  Refers to Section 6 (b) of the the Federal Insecticide, Fungi'.' jt
and Rodenticide Act (F1FRA) which  authorizes cancellation of a pesticide
registration if unreasonable adverse effects  to the environment and p .M'c
health develop when a product is used according to widespread and .  >•--
monly recognized practice, or if its labeling or other material required ; • . c
submitted does  not comply with FIFRA provisions.
Cap: A layer of clay, or other highly impermeable material installed ove •  :.' _•
top of a closed landfill to prevent entry of rainwater and minimize produ'"r.">
of leachate.
Capture Efficiency: The fraction of all organic vapors generated by a pn <: •-
that are directed to  an abatement or recovery device
Carbon Adsorber: An add-on control  device which uses activated carbo;   i
absorb volatile organic compounds from a gas stream  The  VOCs  are L r,
recovered from the  carbon
Carbon Dioxide (CO2): A colorless,  odorless, non-poisonous gas,  w!  ..I.
results from fossil fuel combustion and is normally a part of the ambient /  -
Carbon Monoxide (CO): A colorless,  odorless, poisonous gas produce"'
incomplete fossil fuel combustion
Carboxyhemoglobin: Hemoglobin in which the iron is associated with ca -S i -
monoxide (CO)  The affinity of hemoglobin for CO is about 300 times gr»  •.*.'
than for oxygen
Carcinogen: Any substance that can cause or contribute to the productior, , t
cancer.
Carcinogenic:  Cancer-producing
Carrying Capacity: 1 In recreation management, the amount of use a rec.i a
tion area can sustain without deterioration of its quality. 2. In wildlife mana,;t
ment, the maximum number  of animals an area can support during a g'» e>
period of the year.
Cask: A thick-walled container (usually lead) used to transport radioac  ,,-r
material.  Also  called a coffin
Catanadramous: Fish that swim downstream to spawn.
Catalytic Converter: An air pollution abatement device  that removes poiltu-
ants from motor vehicle exhaust, either by oxidizing them into carbon dioxide
and  water or reducing them to nitrogen and oxygen.

Catalytic Incinerator: A control device which oxidizes volatile organic com-
pounds (VOCs) by using a  catalyst to promote the combustion process
Catalytic incinerators require  lower temperatures than conventional thermal
incinerators, with resultant fuel and cost savings.

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Categorical Exclusion: A class of actions which cither individually or cumula-
tively would not have a significant effect on  the human environment and
therefore would not require preparation of an environmental assessment or
environmental impact statement under the National Environn :ental Policy Act
(NEPA).
Categorical Pretreatment Standard: A technology-based effluent limitation for
an industrial facility  which discharges into a municipal sewer system  An-
alogous in stringency to Best Availability Technology (BAT) for direct dis-
chargers.
Cathodic Protection:  A technique to prevent corrosion of a metal surface by
making that surface the cathode of an electrochemical cell.
Caustic Soda:  Sodium hydroxide, a strong alkaline substance used  as the
cleaning agent in some detergents
CBOD5:  The amount of dissolved  oxygen consumed in  5 days from the
carbonaceous portion of biological processes breaking down in an effluent
The test methodology is the same as for BODS, except that nitrogen demand is
suppressed.
Cells: l.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.
Centrifugal Collector: A mechanical system using centrifugal force to remove
aerosols from a gas stream or to de-water sludge
Cesium (Cs): A silver-white, soft ductile element of the alkali metal group that
is the most electropositive element known. Used especially in photoelectric
cells.
Channelization: Straightening and deepening streams so water will move
faster, a flood-reduction or marsh-drainage tactic that can interfere with waste
assimilation capacity and disturb fish and wildlife habitats
Characteristic: Any one of the four categories used in defining hazardous
waste: ignitabihty, corrosivity, reactivity, and  toxicity
Chemical Oxygen Demand (COD): A  measure of the oxygen required  to
oxidize all compounds in water, both organic  and inorganic
Chemical Treatment: Any one  of a variety of technologies that use chemicals
or a variety of chemical processes to treat waste.
Chemostenlant: A chemical that contiols pests by preventing reproduction.
Chilling Effect: The lowering of the Earth's temperature because of increased
particles in the air blocking the sun's ra\s. (See. greenhouse effect )
Chlorinated Hydrocarbons:  These include a class of persistent, broad-
spectrum insecticides, that linger in the environment and accumulate in the
food chain. Among them  are DDT, aldnn, dieldnn, heptachlor, chlordane,
lindane, endnn, mirex, hexachlonde, and toxaphene Other examples include
TCE,  used as an industrial solvent
Chlorinated Solvent: An  organic solvent containing chlorine atoms, e g
methylene chloride and 1.1,1-tnchloromethane which are used in aerosol
spray containers and in traffic  paint.
Chlorination: The  application  of chlorine to drinking water, sewage, or in-
dustrial waste to disinfect or to oxidize undesirable 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, arid easily liquified
chemicals used in refrigeration, air conditioning, packaging, insulation, or as
solvents and aerosol propellants. Because CFCs are not destroyed in the lower
atmosphere they drift into the  upper atmosphere where their chlorine com-
ponents destroy ozone.
Chlorosis: Discoloration of normally green plant parts, that can be caused by
disease, lack of nutrients,  or various air pollutants.
Chromium: (See. heavy metals.)
Chronic Toxicity: The capacity of a substance  to cause long-term poisonous
human health effects. (See: acute toxicity.)
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.
Clarif ier: A tank in which solids are settled to the bottom and are subsequently
removed as sludge.
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: A forest management technique that involves harvesting .ill the
trees in one area at one time  Under certain soil and slope conditions il can
contribute sediment to water pollution.
Cloning: In biotechnology, obtaining a group of genetically identical cells from
a single cell. This term has assumed a more general meaning that includes
making copies of a gene.
Closed-Loop Recycling: Reclaiming or reusing wastewater for non-potable
purposes in  an enclosed process
Coagulation: A clumping of paiticles in wastewater to settle out impurities It
is often induced  by chemicals suih as lime, alum, and Ton salts
Coastal Zone: Lands and waters adjacent to the coast that exert an influence on
the uses of the sea and its ecology, or, inversely, whose uses and ecology are
affected by the sea
Coefficient of Haze (COH): A measurement of visibility interference in the
atmosphere
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 m water indicates fecal pollution and potentially
dangerous bacterial contamination by disease-causing microorganisms
Combined Sewers: A sewer system that carries both sewage and storm-water
runoff. Normally, its entire flow goes to a waste treitment plant, but during a
heavy storm, the storm water volume may be ; o great as to cause overflows.
When this happens untreated mixtures of storm water and sewage may flow
into receiving waters  Storm-water runoff may also carry toxic chemicals fiom
industrial areas or streets into the sewer system
Combustion: Burning, or rapid oxidation, accompanied by release of energy
in the form of heat and light  A basic cause of an pollution
Combustion Product: Substance produced dut. .g She burning or oxidation o
a material.
Command Post:  Facility located at a sate diot. '..c- i . .  iiid from in acuden
site, where the on-scene coordinator, respor     and  technical .'presenta
fives can make response decisions, deploy manpower and equipment, mam
tain liaison with  news media, and handle communicj:ioj s
Comment Period: Tune provided for the public to review and comment on
proposed EPA action or rulemaking after it is published ir the Federal Regis
ter
Comminution: Mechanical shredding or pulverizing of waste  Used in bot
sohd waste management and wastewater treatment
Comminuter: A  machine that shreds 01 pulvenz.es solids  to  make wast
treatment easier
Community Relations: The EPA effort to establish two-way commumcatio
with the public to create understanding of EPA programs and related action;
to assure  public input into decision-making processes  related to  atfecte
communities, and to make certain that the Agency is aware of and responsiv
to public concerns. Specific community relations activities are required i
relation to Superfund remedial actions
Community Water System: A public water system which serves at least
service connections used by year-round residents or regularly serves at least \
year-round residents
Compaction: Reduction of the bulk of solid waste by rolling and tamping
Compliance Coating: A coating whose volatile organic compound conte
does not exceed  that allowed by regulation.
Compliance Schedule: A negotiated agreement between a pollution sour
and a government agency that specifies dates and procedures by which
source will reduce emissions and, thereby, comply with a regulation.
Compost: A mixture of garbage and degradable trash with soil in which certa
bacteria in the soil break down the garbage and trash into organic fertilize
Composting: The natural biological decomposition ot organic material in t
presence of air to form a humus-like material. Controlled methods of compo
ing include  mechanical mixing and aerating, ventilating the  materials
dropping them through a vertical series of aerated chambers, or placing t
compost in piles out in the open air and mixing it or turning it periodical!;

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Conditional Registration: Under special  circumstances, the Federal In-
secticide,  Fungicide, and Rodenticide Act  (FIFRA) permits  registration of
pesticide products that is "conditional"  upon the submission of additional
data. These special circumstances include a finding by the EPA Administrator
that a new product or use of an existing pesticide will not significantly increase
the risk of unreasonable adverse effects. A product containing a new (pre-
viously unregistered) active ingredient may be conditionally registered only if
the Administrator finds that such conditional registration is in  the public
interest, that a reasonable time for conducting the additional studies has not
elapsed, and the use of the pesticide for the period of conditional registration
will not present an unreasonable risk.
Confined Aquifer: An aquifer in  which ground water is confined under
pressure which is significantly greater than atmospheric pressure.
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 regulations where the PRP's failure to comply caused
EPA to initiate regulatory enforcement actions. The consent decree describes
the actions PRP's will take and may be subject to a public comment period.
Conservation: Avoiding waste of, and renewing when possible, human and
natural resources. The protection, improvement, and use of natural resources
according to principles  that will assure their highest economic or social bene-
fits.
Contact Pesticide:  A chemical  that kills pests when it touches them, rather
than by being eaten (stomach poison). Also, soil that contains the minute
skeletons of certain algae that scratches and dehydrates waxy-coated insects.
Contaminant: Any physical, chemical, biological, or radiological substance or
matter that has an adverse affect on air,  water, or soil.
Contingency Plan: A document setting out an organized, planned, and coor-
dinated course of action to be followed in case of a fire, explosion, or other
accident that releases toxic chemicals,  hazardous wastes, or radioactive mate-
rials which threaten human health or the environment. (See: National Oil and
Hazardous Substances  Contingency Plan.)
Contract Labs: Laboratories under  contract to EPA,  which analyze samples
taken from wastes, soil, air,  and water or carry out research projects.

Contrails: Long, narrow clouds caused when high-flying jet aircraft disturb
the atmosphere
Contour Plowing: Farming methods that break ground following the shape of
the land in a way that  discourages erosion.
Control Technique Guidelines (CTG): A series of EPA documents designed
to assist states in defining reasonable available control technology (RACT) for
major sources of volatile organic compounds (VOC).
Conventional Pollutants: Statutorily listed pollutants which are understood
well by scientists. These may be in the form of organic waste, sediment, acid,
bacteria and viruses, nutrients, oil  and grease, or heat.
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  discharge to surface waters
Coolant: A liquid or gas used to reduce the heat generated by power produc-
tion in nuclear reactors, electric generators, various industrial and mechanical
processes, and automobile engines
Cooling Tower: A structure that helps remove heat from water used as a
coolant, e g , in  electric power generating plants.
Core: The uranium-containing heart  of a nuclear reactor,  where energy is
released.
Corrosion: The dissolving and wearing away of metal caused by a chemical
reaction such as between water and the pipes that the water contacts, chem-
icals 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-Effective Alternative: An alternative control or corrective  method identi-
fied after  analysis as being  the best available in terms of reliability,  per-
manence, and economic considerations  Although  costs are  one important
consideration, when regulatory and compliance methods are being  con-
sidered, such analysis  does  not require  EPA to choose the least expensive
alternative. For example, when selecting a method for cleaning  up a site on the
Superfund National Priorities List,  the Agency balances costs with the long-
term effectiveness  of the various methods proposed
 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.
 Cover: Vegetation or other material providing protection as ground cover.
 Cover Material: Soil used to cover compacted solid waste in a sanitary landfill.
 Crawl Space: In some types of houses, which are constructed so that the floor
 is raised slightly  above the ground, an area beneath the floor which allows
 access to utilities and other services. This is in contrast to slab-on-grade or
 basement construction houses.
 Criteria: Descriptive factors taken into account by EPA in setting standards for
 various pollutants. These factors are used to determine limits on allowable
 concentration 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 amendments 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.
 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 exchanged with indoor air in a minute's
 time, or  an air exchange rate.
 Cultural Eutrophication: Increasing rate at which water bodies "die" by pollu-
 tion from human activities.
 Cumulative Working Level Months (CWLM): The sum of lifetime exposure to
 radon working levels expressed in total working level months.
 Curie: A quantitative measure of radioactivity equal to 3.7 x 1010 disintegra-
 tions per second.
 Cutie-Pie: An instrument used to measure radiation levels.
 Cyclone  Collector: A device that uses centrifugal force to pull large particles
 from polluted air.
DDT: The first chlorinated hydrocarbon insecticide (chemical name: Dichloro-
Diphsdyl-Trichloromethane). 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.
Data Call-In: A part of the Office of Pesticide  Programs (OPP) process of
developing key required test data, especially on the long-term, chronic effects
of existing pesticides, in advance of scheduled Registration Standard reviews.
Data Call-In is an adjunct of the Registration Standards program intended to
expedite reregistration and involves the "calling  in"  of data from man-
ufacturers
Dechlorination: Removal of chlorine from a substance by chemically replacing
it with hydrogen or hydroxide ions in order to detoxify the  substances in-
volved.
Decibel (dB): A unit of sound measurement. In  general, a sound doubles in
loudness for every increase of ten decibels
Decomposition: The breakdown of matter by bacteria and fungi. It  changes
the chemical makeup and physical appearance of materials.
Degradation: The process by which a chemical is reduced to  a less complex
form.

Delegated State: A state (or other governmental entity) which has applied for,
and received authority to administer, within its  territory, its state regulatory
program as the federal program required under a particular federal statute. As
used m connection with NPDES, UIC, and PWS  programs, the term does not
connote any transfer of federal authority to a state
Defoliant: A herbicide that removes leaves from trees and growing plants
Delist: Use of the petition process to  have a facility's toxic designation res-
cinded.

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Denitrification: The anaerobic biological reduction of nitrate nitrogen to nit-
rogen gas.
Depletion Curve: In hydraulics, a graphical representation of water depletion
from storage-stream channels, surface soil, and ground water. A depletion
curve can be drawn for base flow, direct runoff, or total  flow.
Depressurization: A condition that occurs when the air pressure inside a
structure is lower that the air pressure outside. Depressurization can occur
when household appliances that consume or exhaust house  air, such as
fireplaces or furnaces, are not supplied with enough makeup air. Radon-
containing  soil gas may be drawn into a  house more  rapidly under de-
pressurized conditions.
Dermal Toxicity: The ability of a pesticide or toxic chemical to poison people or
animals by contact with the skin. (See: contact pesticide.)
DES: A synthetic estrogen, diethylstilbestrol is used as a growth stimulant in
food animals. Residues in meat are thought to be carcinogenic.
Desalinization: Removing salt from ocean or brackish water.
Desiccant: A chemical agent that absorbs moisture; some desiccants are cap-
able of drying out plants or insects, causing death.
Designated Pollutant: An air pollutant  which is neither  a criteria nor
hazardous pollutant, as described in the Clean Air Act, but for which new
sources performance standards exist. The Clean Air Act does require states to
control these pollutants, which include acid mist, total reduced sulfur (TRS),
and fluorides.
Designer Bugs: Popular term for microbes developed through biotechnology
that can degrade specific toxic chemicals at their source in toxic waste dumps
or in ground water
Desulfurization: Removal of sulfur from fossil fuels to reduce pollution.
Designated Uses: Those water uses identified in state water quality standards
which must be achieved and maintained as required under the Clean Water
Act. Uses can include cold water fisheries, public water supply, agriculture,
etc.
Detergent:  Synthetic washing agent that helps to remove dirt and oil. Some
contain compounds which kill useful bacteria and encourage algae growth
when they are in wastewater that reaches  receiving waters.
Developer: A person,  government unit, or company that proposes to build a
hazardous  waste treatment, storage, or disposal facility.
Diatomaceous Earth (Diatomite): A chalk-like material (fossilized diatoms)
used to filter out solid waste in waste-water 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 who
gathered on them in  large numbers.  The ban did not apply to  its  use in
agriculture,  or on lawns of homes and commercial establishments.
Dicofol: A  pesticide used on citrus fruits
Differentiation: The process by which single cells grow into particular forms
of specialized tissue, e.g., root,  stem, leaf.
Diffused Air: A type of aeration that forces oxygen into sewage by pumping
air through perforated pipes inside a holding tank and bubbling it through the
sewage.
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  decomposition of organic matter, resulting in
partial gasification, liquefaction, and mineralization of pollutants.
Dike:  A low wall that can act as a barrier to prevent a spill from spreading.
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.
Dinocap: A fungicide used primarily by apple growers  to control summer
diseases. EPA, in 1986, proposed restrictions on its use when laboratory tests
found it caused birth defects in rabbits.
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 and contami-
nants in commercial products. Tests on laboratory animals indicate that it is
one of the more toxic man-made chemicals known.
Direct Discharger: A municipal or industrial facility which introduces pollu-
tion through a defined conveyance or system;  a point source.
Disinfectant: A chemical or physical process that kills pathogenic organisms
in water. Chlorine is often used to disinfect sewage treatment effluent, water
supplies, wells, and swimming pools.
Dispersant: A chemical agent used to break up concentrations of organic
material such as spilled oil.
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.
Dissolved  Oxygen  (DO):  The oxygen freely available  in water. Dissolved
oxygen is vital to fish and  other aquatic life and for the prevention of odors.
Traditionally, the level of dissolved oxygen has been accepted  as the  single
most important indicator of a water body's ability to support desirable aquatic
life.  Secondary and advanced waste treatment are generally  designed to
protect DO in waste-receiving waters.
Dissolved Solids: Disintegrated organic  and inorganic material contained in
water. Excessive amounts make water  unfit to drink  or use  in industrial
processes.
Distillation: The act of purifying liquids through boiling, so that the  steam
condenses  to a pure liquid and the pollutants remain in a concentrated resi-
due.
DNA: Deoxyribonucleic acid, the molecule in which the genetic information
for most living cells is  encoded. Viruses, too, can contain RNA
DNA Hybridization:  Use of a segment of DNA, called  a  DNA probe, to
identify its  complementary DNA; used to detect specific genes  This process
takes advantage of  the ability of a single strand of DNA to combine with a
complimentary strand.
Dose: In radiology, the quantity of energy or radiation  absorbed.
Dosimeter: An instrument that measures exposure to radiation.
Dredging: Removal of mud from the bottom of water bodies using a scooping
machine. This disturbs the ecosystem and causes silting that can kill aquatic
life. Dredging of contaminated muds can expose aquatic life to heavy metals
and  other  toxics. Dredging activities may be subject to regulation  under
Section 404 of the Clean Water Act.
Dump: A site used to dispose of solid wastes without environmental controls.
Dust: Particles light enough to be suspended in air.
Dustfall Jar: An open container used to collect large particles from the air for
measurement and analysis
Dystrophic Lakes: Shallow bodies of water that contain much humus and/or
organic matter, that contain many plants but few fish and are highly acidic.
Ecological Impact: The effect that a man-made or natural activity has on living
organisms and their non-living (abiotic) environment.
Ecology: The relationship of living things to one another and their environ-
ment, 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 contains life on earth, in surface waters, and
in the air. (See; biosphere.)
Ecosystem:  The interacting system  of a biological community and its non-
living environmental surroundings.
Effluent: Wastewater—treated or untreated—that flows out of a treatment
plant, sewer, or industrial outfall. Generally refers to wastes discharged into
surface waters.

Effluent Limitation: Restrictions established by a State  or EPA on quantitie-
s,rates, and concentrations in wastewater discharges.
Electrodialysis: A process that uses electrical current applied to permeable
membranes to remove minerals from water. Often used to desalinize salty or
brackish water.

Electrostatic Precipitator (ESP): An air pollution control device that removes
particles from a gas stream (smoke) after combustion occurs. The ESP imparts
an electrical charge to the particles, causing them to adhere  to metal plates
inside the precipitator. Rapping on the plates causes the particles to fall into a
hopper for disposal.
Eligible Costs: The construction costs for waste-water treatment works upon
which EPA  grants are based.

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Emergency (Chemical): A situation created by an accidental release or spill ot
hazardous chemicals which poses a threat to the safety of workers, residents,
the environment, or property
Emergency Episode: (See. air pollution episode.)
Eminent Domain: Government taking—or forced acquisition—of private land
for public use, with compensation paid to the landowner
Emission: Pollution discharged into the atmosphere from smokestacks, other
vents, and surface areas of commercial or industrial facilities; from residential
chimneys; and from  motor vehicle, locomotive,  or aircraft exhausts.

Emission Factor: The relationship between the amount of pollution produced
and the amount of raw material processed. For example, an emission factor for
a blast furnace making iron would be the number of pounds of particulates per
ton of raw materials.
Emission Inventory: A listing, by source, of the amount of air pollutants
discharged into the atmosphere of a community. It is used to  establish emis-
sion standards.
Emission Standard: The maximum amount of air polluting discharge legally
allowed from a single source, mobile or stationary.
Emissions Trading:  EPA policy that  allows a  plant complex with  several
facilities to decrease pollution from some facilities  while increasing  it  from
others,  so long as total results are equal to or  better than previous limits.
Facilities where this is done are treated as if they exist in a bubble in which total
emissions are averaged out Complexes that reduce emissions substantially
may "bank" their "credits" or sell them to other industries

Endangered Species: Animals, birds, fish, plants, or other  living organisms
threatened with extinction by man-made or natural changes in their environ-
ment. Requirements for declaring a species endangered are contained in the
Endangered Species  Act.
Endangerment Assessment: A study conducted to determine the nature and
extent of contamination at a site on the National Priorities List and the risks
posed to public health or the environment. EPA or the state conduct the study
when a  legal action is to be taken to direct potentially responsible parties to
clean up a site or pay for the cleanup. An endangerment assessment supple-
ments a remedial investigation
Enforcement: EPA, state, or local legal actions to  obtain compliance with
environmental laws, rules, regulations, or agreements and/or obtain penalties
or criminal sanctions for violations Enforcement procedures  may vary, de-
pending on the  specific requirements of  different environmental laws and
related implementing regulatory requirements. Under CERCLA, for example,
EPA will seek to require potentially responsible  parties to clean up a  Super-
fund site, or pay for the cleanup, whereas under the Clean Air Act the agency
may invoke sanctions against cities failing to meet ambient air quality stan-
dards that could prevent certain types 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 ex-
planation to the public of EPA's selection of the cleanup alternative at enforce-
ment sites on the National Priorities List. Similar to a Record of Decision.
Enrichment: The addition of nutrients (e g , nitrogen, phosphorus,  carbon
compounds) from sewage effluent or agricultural  runoff to surface water. This
process  greatly increases  the growth potential for algae and aquatic plants
Environment: The  sum of all external  conditions affecting the life, develop-
ment and survival  of an organism.
Environmental Assessment: A written environmental analysis which is pre-
pared pursuant to the National Environmental Policy Act to determine
whether a federal action would significantly affect the environment and thus
require  preparation of a more detailed environmental impact statement.
Environmental Audit: 1. An independent assessment of the current status of a
party's compliance with applicable environmental  requirements. 2  An in-
dependent evaluation of a party's environmental compliance policies, prac-
tices, and controls.

Environmental Impact Statement: A document required of federal agencies by
the National Environmental Policy Act for ma|or projects or legislative pro-
posals significantly affecting the environment A tool for decision making, it
describes the positive and negative effects of the undertaking and lists alterna-
tive actions
i nvircnmenlal Response  Team: '. PA
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Fabric Filter: A cloth device that catches dust particles from industrial emis-
sions
Feasibility Study: 1. Analysis of the practicability of a proposal; e g., adescnp-
tion and analysis of the potential cleanup alternatives for a site or alternatives
for a site on the National Priorities  List.  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". The term can apply to a variety of proposed corrective or
regulatory actions. 2. In research, a small-scale investigation of a problem to
ascertain whether or not 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.
Feedlot: A relatively small, confined area for the controlled feeding of animals
that tends to  concentrate large amounts of animal wastes that cannot be
absorbed by the soil and, hence, may be carried to nearby streams or lakes by
rainfall runoff.
Fen: A type of wetland that accumulates peat deposits. Fens are less acidic
than bogs, deriving most of their water from groundwater rich in calcium and
magnesium. (See: wetlands.)
Fermentation: Chemical reactions accompanied  by  living microbes that are
supplied with nutrients and other critical conditions such as heat, pressure,
and light that are specific to the reaction at hand.
Fertilizer: Materials such as nitrogen and phosphorus that provide nutrients
for plants. Commercially sold fertilizers may contain other chemicals or may
be in the form of processed sewage  sludge.
Filling: Depositing dirt and  mud or other materials into aquatic areas to create
more dry land, usually for agricultural or commercial development purposes.
Such activities often damage the ecology of the area.
Filtration: A treatment process, under the control of qualified operators, for
removing solid (particulate) matter from water by passing the water through
porous media such as sand or a man-made filter.  The process is often used to
remove particles that contain pathogenic organisms.
Finding of No Significant Impact: A document prepared by a federal agency
that presents the reasons impact: 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.
First Draw: The water that immediately comes out when a tap is first opened.
This water is  likely to have  the highest level  of lead contamination from
plumbing materials.
Floe: A clump of solids formed in sewage by biological or chemical  action
Flocculation: The process by which clumps of solids in water or sewage are
made to increase in size by biological or chemical action so that they can be
separated from the water.
Floor Sweep: A vapor collection designed to capture vapors which are heavier
than air and which collect along the floor.
Flowmeter: A gauge that shows the speed of wastewater moving through  a
treatment plant. Also used to measure the speed of liquids 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 which uses a sorbent, usually lime or
limestone, to remove sulfur dioxide from the gases produced by burning fossil
fuels. Flue gas desulferization is curient the state-of-the art technology m use
by major  SO2 emitter, e.g , power plants
Fluorides: Gaseous, solid, or dissolved compounds containing fluorine that
result from industrial processes. Excessive amounts in food can lead to tluor
Fluorocarbon (FCs): Any of a number  of organic compounds analogous to
hydrocarbons in which one or more hydrogen atoms are replaced by fluorine
Once used 1:1 tne Ui'itod Start"- as  j piopellant in aerosols, they are  now
primarily u?ed in coolants ^nd some industrial processes  FCs containing
chlorine are called i h'oroihuroLnrbon;. (Q'Csi  Ihe\ ate believed to bi1 mc'd-
>f"ms the cz'ine la-vr ip the ti'.itu'-rhor.1, thei.'ln  allowini; mor?  harm.i'l
•lo'ar r.idiatuvi M » j,ih i\~-. i'arth's ,u.i, ~>
Flume: A natural or man-made channel that diverts water
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 s\stern
means to send large volumes of water gushing through the unused pipes to
remove  loose particles of solder and flux. 2. To force large amounts of water
through liquid to clean out piping or tubing, storage or process tanks.
Fly Ash: Non-combustible residual particles from the combustion process,
carried 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. It may be 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.
Formaldehyde:  A colorless, pungent, irritating gas, CH20, used chiefly as a
disinfectant and preservative and in synthesizing other compounds and re-
sins.
Formulation: The substance or mixture of substances which is comprised of all
active and inert ingredients in  a pesticide.
Fresh Water: Water that generally contains less than 1,000 milhgrams-per-hter
of dissolved solids,
Fuel Economy Standard: The  Corporate Average Fuel Economy Standard
(CAFE) which went into effect  m 1978. It was meant to enhance the national
fuel conservation effort by slowing fuel consumption  through a  miles-per-
gallon requirement for motor vehicles.
Fugitive Emissions: Emissions not caught by a capture system.
Fume: Tiny particles trapped in vapor in a gas stream.
Fumigant: A pesticide that is vaporized to kill pests. Used in buildings and
greenhouses.
Functional Equivalent: Term used to describe EPA's decision-making process
and its relationship to the environmental review conducted under the Nation-
al Environmental Policy Act (NEPA). A  review is considered functionally
equivalent when it addresses the substantive components of a NEPA review.
Fungi: (Singular, Fungus) Molds, mildews, yeasts, mushrooms,  and puff-
balls,  a group organisms that lack chlorophyll (i.e , are not photosynthetic)
and which are usually non-mobile, filamentous, and multicellular. Some grow
in the ground, others attach themselves to decaying trees and other plants,
getting their nutrition from decomposing organic matter. Some cause disease,
others stabilize sewage and break down solid wastes in composting.
Fungicide: Pesticides which are used to control, prevent, or destroy fungi.
Game Fish: Species like trout, salmon, or bass, caught for sport. Many of them
show more sensitivity to environmental change than "rough" fish.
Gamma Radiation: Gamma rays are true rays of energy in contrast to alpha
and beta radiation  The properties are similar to  x-rays and  other
electromagnetic waves. They are the most penetrating waves of radiant nu-
clear energy but can be blocked by dense materials such as lead.
Gasification: Conversion of solid material such as coal into a gas for use as a
fuel.
Geiger Counter: An electrical device that detects the presence of certain types
of radioactivity.
Gene: A length of DNA that directs the synthesis of a protein
Gene Library: A collection of DNA fragments from cells or organisms So far,
no simple way for sorting the contents of gene libraries has been devised
However, DNA pieces can be moved into bacterial cells where sorting accord-
ing to gene function becomes feasible
Genera] Permit: A permit applicable to a class or category of dischargers
Generator: A facility or mobile source that emits pollutants into the air or
releases hazardous wastes into water  or soil
Genetic Engineering: A  process of inserting neu  genetic information  inlo
existing cells  in order to modify any organism toi the purpose of changing one
of its characteristics
Germicide: Am compound  that kills  disease-causing nnrn.or>',a'n-,ii's
Gtain Loading: The rate .it u  huh parhcieiau'emitlecl rmm<' pollution SCKIIM'
 Grain:!?," Activated Carbon  Freatmen;

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Gray Water: The term given to domestic wastewater composed of washwater
from sinks, kitchen sinks, bathroom sinks and tubs, and laundry tubs
Greenhouse  Effect: The warming of  the  Earth's atmosphere caused by a
build-up of carbon dioxide or other trace gases, it is believed by many scientists
that this build-up allows light from the sun's rays to heat the Earth  but
prevents a counterbalancing loss of heat
Grinder Pump: A mechanical device which shreds solids and raises the fluid to
a higher elevation through pressure sewers
Gross Alpha Particle Activity. Total activity due to emission of alpha particles.
Used as the screening measurement for radioactivity generally due to
naturally-occurring radionudides  Activity is commonly measured in picocur-
ies.
Gross Beta Particle  Activity: Total activity  due to emission of beta particles.
Used as the screening  measurement for radioactivity from  man-made
radionudides since the decay products of fission are beta particle and gamma
ray emitters.  Activity  is commonly measured in picocuries
Ground Cover: Plants grown to keep soil from eroding
Ground Water: The supply of fresh water found beneath the Earth's surface,
usually in aquifers, which is often used for supplying wells and springs.
Because ground water is a major source of drinking water there is growing
concern over areas  where leaching agricultural or industrial pollutants or
substances from leaking underground storage tanks are contaminating
ground water.

H
Habitat: The  place where a population ( e.g., human, animal, plant, micro-
organism) lives and its surroundings, both living and non-living

Half-Life: 1.  The time required for a pollutant to lose half its affect on  the
environment. For example, the half-life of DDT in the environment is 15 years,
of radium, 1,580 years 2. The time required for half of the atoms of a radioac-
tive element to undergo decay. 3. The time required for the elimination of one
half a total dose from the body
Halogen: Any of  a group of 5 chemically-related nonmetalhc elements that
includes bromine, fluorine, chlorine, iodine, and astatine.
Halon:  Bromine-containing compounds with long atmospheric lifetimes
whose breakdown in the stratosphere cause depletion of ozone.  Halons are
used in fire-fighting.
Hammermill: A high-speed machine that hammers and cutters to crush, grind
chip, or shred solid wastes
Hard Water: Alkaline water containing dissolved salts that interfere with some
industrial processes and prevent soap from lathering.
Hazardous Air Pollutants: Air pollutants which are not covered  by ambient
air quality standards but which, as defined  in the Clean Air Act, may reason-
ably be expected to  cause or contribute to irreversible illness or death. Such
pollutants include asbestos, beryllium, mercury,  benzene, coke  oven emis-
sions, radionudides, and vinyl  chloride
Hazardous Ranking System: The principle screening tool used  by EPA to
evaluate risks to public health and the environment associated  with aban-
doned or uncontrolled hazardous waste sites  The HRS calculates a score
based on the potential  of hazardous substances spreading from the site
through the air, surface water, or ground water and on other factors such as
nearby  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 if otherwise emitted  to the environment
Hazardous Waste: By-products of society that can pose a substantial or poten-
tial hazard to human health or the environment when improperly managed
Possesses at least one  of four characteristics (ignitabihty, corrosivity, reactiv-
ity, or toxicity), or appears on special EPA lists
Hazards Analysis:  The procedures involved in (1)  identifying potential
sources of release of hazardous materials from fixed facilities or transportation
accidents, (2)  determining, the vulnerability  of a geographical area  to a release
of hazardous materials, and (3) comparing hazards to  determine which  pr-
esent greatei  or lesser risk<- to a community
Hazards Identification.  Porviding  information on nh.ch tncilitie^ ha', c  e\-
tiemeh  hazardous substances, u ha tlhoce chemicals a le, and ho\\  much there
s at each facility
                           also providt> i.nfc>riruii'C'n on ho~v tho chc-rrv.caK
                                                                        Heat Island Effect: A "dome" of elevated temperatures over an urban area
                                                                        caused by structural and pavement heat fluxes, and pollutant emissions from
                                                                        the area below the dome.
                                                                        Heavy Metals: Metallic elements with high atomic weights,  e g , mercury,
                                                                        chromium, cadmium, arsenic, and lead  They can damage living things at low
                                                                        concentrations and tend to accumulate in the food chain
                                                                        Heptachlor: An insecticide that was banned on some food products in 1975
                                                                        and all of them 1978. It was allowed for use in seed treatment until in 1983.
                                                                        More recently it was found in milk and other dairy products in Arkansas and
                                                                        Missouri, as a result of illegally feeding treated seed to dairy cattle
                                                                        Herbicide: A chemical pesticide designed to control or destroy plants, weeds,
                                                                        or grasses
                                                                        Herbivore: An animal that feeds on plants.
                                                                        Heterotrophic  Organisms: Consumers such  as humans and animals, and
                                                                        decomposers—chiefly bacteria and fungi—that are dependent on organic
                                                                        matter for food.
                                                                        High-Density Polyethylene: A material that produces toxic fumes  when
                                                                        burned. Used to make plastic bottles and other products
                                                                        High-Level Radioactive Waste (HLW): Waste generated in the  fuel of a nu-
                                                                        clear reactor, found at nuclear reactors or nuclear fuel reprocessing plants. It is
                                                                        a serious threat to anyone who comes near the wastes without shielding (See
                                                                        Low-Level Radioactive Waste).
                                                                        Holding Pond: A pond or reservoir, usually made of earth, built to store
                                                                        polluted runoff.
                                                                        Hood Capture Efficiency: The emissions from a process which are captured by
                                                                        hood and directed into the  control  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 by
                                                                        or parasitized by another organism.
                                                                        Humus: Decomposed organic material
                                                                        Hybrid: A cell or organism resulting from a cross between two unlike plant or
                                                                        animal cells or organisms.
                                                                        Hybridoma: A hybrid cell that produces monoclonal antibodies in large quan-
                                                                        tities.
                                                                        Hydrocarbons (HC): Chemical compounds that consist entirely of carbon and
                                                                        hydrogen.
                                                                        Hydrogen Sulfide (HS): Gas emitted during organic decomposition Also a
                                                                        byproduct of oil refining and burning. It smells like rotten eggs and, in heavy
                                                                        concentration, can cause illness
                                                                        Hydrogeology: The geology of ground water, with particular emphasis on the
                                                                        chemistry and movement of water.
                                                                        Hydrology: The science dealing with the properties,distnbution, and circula-
                                                                        tion of water.

                                                                        I

                                                                        Ignitable: Capable of burning or causing a fire.
                                                                        Impoundment: A body of water or sludge confined by a dam, dike, floodgate,
                                                                        or other barrier.
                                                                        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 symptom.
                                                                        Used as a "level of concern." (See. level of concern.)
                                                                        In Vitro: 1. "In glass", a test-tube culture  2 Any laboratory test using living
                                                                        cells taken from an organism.
                                                                        In Vivo: In the living body of a plant  or animal. In vivo tests are  those
                                                                        laboratory experiments carried out on whole animals 01 human volunteers
                                                                        Incineration: 1. Burning of certain types of solid, liquid  or gaseous materials
                                                                        2 A treatment technology involving destruction ot waste by controlled burn-
                                                                        ing at high temperatures, eg., burning sludge to remove the water and reduce
                                                                        the remaining  residues to a safe, non-burnable ash which can be disposed of
                                                                        safely OP land, in some waters or in underground locations
                                                                        Incineration at Sea: Disposal of waste b\ burning at "-ea on speciallv-dt-signed
                                                                        incinerator ships
                                                                        Incinerator: A furnace for  burning wastes under controlled conditions.
                                                                        Indicator: In biology, an organism, species, or communitv whose characteris-
                                                                        tics show the presence ot specific environmental conditions
Jtt  stoied and whcthei thev arc used at high temperatuies

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Indirect Discharge: Introduction of pollutants from a non-domestic source
into a publicly owned waste treatment system. Indirect dischargers can be
commercial or industrial facilities whose wastes go into the local sewers
Indoor Air: The breathing air inside a habitable structure or conveyance.
Indoor Air Pollution: Chemical, physical, or biological contaminants in indoor
air.
Indoor Climate: Temperature,  humidity, lighting and noise levels in a habit-
able structure or conveyance. Indoor climate can affect indoor air pollution.
Inert Ingredient: Pesticide components such as solvents, carriers, and sur-
factants that are not active against target pests. Not all inert ingredients are
innocuous.
Inertial Separator: A device that uses centrifugal force  to  separate waste
particles.
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  A land
application technique where large volumes of waste water are applied to land,
allowed to penetrate the surface and percolate through the underlying soil.
(See: percolation)
Inflow: Entry of extraneous rain water into a sewer system from sources other
than infiltration, such as basement drains, manholes, storm drains, and street
washing.
Influent: Water, wastewater, or other liquid flowing into a reservoir, basin, or
treatment plant.
Information File: In the Superfund program, a file that contains accurate,
up-to-date documents on a Superfund site. The file is usually located in a
public building such as a school, library, or city hall that is convenient for local
residents.
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, group of formations, or part of a
formation receiving fluids through a well.
Inoculum: 1. Bacterium placed in compost to start biological action. 2. A
medium containing organisms which is introduced into cultures or living
organisms,
Inorganic Chemicals: Chemical substances of mineral origin, not  of basically
carbon structure.
Insecticide: A pesticide compound specifically used to kill or control the
growth of insects.
Inspection and Maintenance (I/M): 1. Activities to assure proper emissions-
related operation of mobile sources of air pollutants, particularly automobile
emissions controls.  2. Also applies to to wastewater treatment  plants and
other anti-pollution facilities and processes.
Instream Use: Water use taking place within a stream channel, e.g., hydro-
electric power generation, navigation, water-quality improvement, fish pro-
pagation,  recreation.
Integrated Pest Management (IPM): A mixture of pesticide and non-pesticide
methods to control pests.
Interceptor Sewers: Large sewer lines that, in a combined system, control the
flow of the sewage to the treatment plant. In a storm, they allow some of the
sewage to flow directly into a receiving stream, thus preventing an overload by
a sudden  surge of water into the sewers. They are also used in separate
systems to collect the flows from main and trunk sewers and carry them to
treatment points.
Interim (Permit) Status: Period during which treatment, storage and disposal
facilities coming under RCRA  in 1980 are temporarily permitted to operate
while awaiting denial or issuance of a permanent permit. Permits issued under
these circumstances are usually called "Part A" or "Part B" permits
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 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.
Inventory: TSCA inventory of chemicals produced pursuant to Section 8 (b) of
the Toxic Substances Control Act.
Inversion: An atmospheric condition caused by a layer of warm air preventing
the rise of cooling air trapped beneath it  This prevents the rise ot pollutants
that might otherwise be dispersed  and c
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Level of Concern (LOG): The concentration in air of an extremely hazardous
substance above which there may be serious immediate health effects to
anyone exposed to it for short periods of bme
Lift: In a sanitary landfill, a compacted layer of solid waste and the top layer of
cover material.
Lifting  Station:  (See: pumping station )
Limestone Scrubbing:  Process in which sulfur gases moving towards a
smokestack are  passed  through a limestone and water solution to remove
sulfur before it reaches the atmosphere.
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 grow or even survive.
Limnology: The  study of the physical, chemical, meteorological, and biologi-
cal aspects of fresh water.
Liner: 1. A relatively impermeable barrier designed to prevent leachate from
leaking  from a landfill. Liner materials include plastic and dense clay. 2. An
insert or sleeve for sewer pipes to prevent leakage or infiltration.
Lipid Solubility: The maximum concentration of a chemical that will dissolve
in fatty  substances; lipid soluble substances are insoluble in water. If a sub-
stance is lipid soluble it will very selectively disperse through the environment
via living tissue.
Liquefaction: Changing a solid into a liquid.
List: Shorthand term for EPA list of violating facilities or list of firms debarred
from obtaining government contracts because they violated certain sections of
the Clean Air or Clean Water Acts. The list is  maintained by The Office of
Enforcement and Compliance Monitoring
Listed Waste: Wastes listed as hazardous under RCRA but which have not
been subjected to the Toxic Characteristics Listing Process because the dan-
gers they present are considered self-evident.
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.
Lower Explosive Limit (LED: The concentration of a compound in air below
which a flame will not propagate if the mixture is ignited.
Lowest  Achievable Emission Rate: Under the Clean Air Act, this is the rate of
emissions which reflects (a) the most stringent emission limitation which is
contained in the  implementation plan of any state for such source unless the
owner or operator of the proposed source demonstrates such limitations are
not achievable; or (b) the most stringent emissions limitation achieved in
practice, which  ever is  more stringent.  Application of this term does not
permit a proposed new or modified source to emit pollutants in excess of
existing new source standards.
Low-Level Radioactive Waste (LLRW):  Wastes less hazardous than most of
those generated by a nuclear reactor. Usually generated by hospitals, research
laboratories, and certain industries. The Department of Energy, Nuclear Reg-
ulatory Commission, and EPA share responsibilities for managing them (See:
high-level radioactive wastes )

M
Marine  Sanitation Device: Any equipment installed on board a vessel to
receive, retain, treat,  or discharge sewage and any process to treat such
sewage.
Major Modification: This term is used to define modifications with respect to
Prevention of Significant Deterioration and New Source Review under the
Clean Air Act and  refers to  modifications to  major stationary  sources of
emissions and provides  significant pollutant increase levels below which a
modification is not considered major
Major Stationary Sources: Term used to determine to applicability of Preven-
tion of Significant Deterioration and new source regulations In a nonattam-
ment area,  any stationary pollutant source that has a 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 type of source.
Manufacturers Formulation: A list of substances or component parts as de-
scribed  by the maker of a coating,  pesticide or other product containing
chemicals or other substances
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 and tidal or non-tidal. (See: wetlands.)
Matabolite: Any  substance produced m or by biological processes and derived
from a pesticide.
Material Safety Data Sheet (MSDS):  A compilation of information required
under 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 circum-
stances.
Maximum Contaminant Level: The maximum permissible level of a contami-
nant in water delivered to any user of a  public water system. MCLs are
enforceable standards.
Mechanical Aeration: Use of mechanical energy to inject air into water to
cause a waste stream to absorb oxygen.
Mechanical Turbulence: Random irregularities of fluid motion in air caused
by buildings or mechanical, non-thermal, processes.
Media: Specific  environments—air, water, soil—which are the subject of
regulatory concern and activities.
Mercury: A heavy metal that can accumulate in the enivornment and is highly
toxic if breathed or swallowed. (See: heavy metals.)
Methane: A colorless, nonpoisonous, flammable gas created by anaerobic
decomposition of organic compounds
Method 18: An EPA test method which uses gas chromatographic techniques
to measure the concentration of individual 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.
Million-gallons Per Day (MGD): A measure of water flow.
Microbes: Microscopic organisms such as algae, animals, viruses, bacteria,
fungus, and protozoa, some of which cause diseases. (See: microorganism )
Microbial Pesticide: A microorganism that is used to control a pest. They are
of low toxicity to man
Microorganism: Living organisms so small that individually they can usually
only be seen through  a microscope
Mist: Liquid particles  measuring 500 to 40 microns, that are formed by con-
densation of vapor. By comparison, "fog" particles are  smaller than 40 micro-
ns.
Mitigation: Measures  taken to reduce adverse impacts on the environment.
Mixed Liquor: A mixture of activated sludge and water containing organic
matter undergoing activated skidge treatment in an aeration tank.
Mobile Source: A moving producer of air pollution, mainly forms of transpor-
tation such as cars,  trucks, motorcycles, airplanes.
Modeling: An investigative technique using a mathematical or physical repre-
sentation of a system or theory that accounts for all or some its  known
properties. Models  are often used to test  the effect  of changes of system
components on the  overall performance of the system.
Model Plant: A description of a typical but theoretical plant used for develop-
ing economic, environmental impact and energy impact analyses as support
for regulations or regulatory guidelines. It is an imaginary plant, with features
of existing or future plants used to  estimate the  cost of incorporating  air
pollution control technology as the first step in exploring the economic impact
of a potential NSPS.
Monitoring: Periodic or continuous surveillance or testing to determine the
level of compliance with statutory requirements and/or pollutant levels in
various media or in humans, animals, and other living things.
Monitoring Wells: Wells drilled at a hazardous waste management facility or
Superfund site to collect ground-water samples for the purpose of physical,
chemical, or biological analysis to determine the amounts, types, and distribu-
tion of contaminants in the ground water beneath the site.
Monoclonal Antibodies: (Also called MABs and MCAs) 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.
Muck Soils: Earth made from decaying plant materials.
Mulch: A layer of material  (wood chips, straw, leaves, etc.) placed around
plants to hold moisture, prevent weed growth, protect the plants, and enrich
the soil.
Multiple Use: Use of land for more than one purpose, i.e., grazing of livestock,
wildlife production, recreation, watershed, and timber production. Could also
apply to use of bodies of water for recreational purposes, fishing, and water
supply.
                                                                                                                                          11

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 Mutagen: Any substance that can cause a change in genetic material
 Mutate: To bring about a change in the genetic constitution of a cell by altering
 its DNA. In turn, "mutagenesis" is any process by which cells are mutated

 N
 National Ambient Air Quality Standards (NAAQS):  Air quality standards
 established by EPA that apply to outside air throughout the country  (See.
 criteria pollutants, state implementation plans, emissions trading )
 National Emissions Standards For Hazardous Air Pollutants (NESHAPS):
 Emissions standards set by EPA for an air pollutant not covered by NAAQS
 that may cause an increase in deaths or in serious, irreversible, or incapacitat-
 ing illness. Primary standards are designed to  protect  human health, secon-
 dary standards to protect public welfare
 National Oil and Hazardous Substances Contingency Plan (NOHSCP/NCP):
 The federal regulation that guides determination of the sites to be corrected
 under the Superfund program and the program to prevent or control spills
 into surface waters or other portions of the environment
 National Pollutant Discharge  Elimination System (NPDES): A provision of
 the Clean Water Act which prohibits discharge of pollutants into waters of the
 United States unless  a special permit is issued by EPA, a state, or (where
 delegated) a  tribal government on an  Indian reservation
 National Priorities List (NPL): EPA's list of the most serious uncontrolled or
 abandoned hazardous waste sites identified for possible long-term remedial
 action under Superfund. A site must be on the NPL to receive money from the
 Trust Fund for remedial action 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.
 National Response Center: The federal operations center that receives noti-
 fications of all releases of oil and hazardous substances into the environment.
 The Center, 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): Representatives of 13 federal agencies that,
 as a team, coordinate federal responses to nationally significant incidents of
 pollution and provide advice and technical assistance to the responding agen-
 cy(ies) before and  during  a response action.
 Natural Gas: A natural fuel containing primarily methane and ethane that
 occurs in certain geologic  formations.
 Natural Selection: The process of survival of the fittest, by which organisms
 that adapt to their environment survive and those that do not disappear.
 Navigable Waters: Traditionally, waters sufficiently deep and wide for
 navigation by all, or specified sizes of vessels; such waters in the United States
 come under federal jurisdiction and are included in certain provisions of the
 Clean Water Act.
 Necrosis: Death of plant or animal cells. In plants, necrosis can discolor areas
 on the plant  or kill it  entirely.
 Nematocide: A chemical  agent which is destructive to  nematodes (round
 worms or threadworms.)
 Neutralization: Decreasing the acidity or alkalinity of a substance by adding to
 it alkaline or acidic materials respectively
 New Source: Any stationary source which is built or modified after publication
 of final or proposed regulations that  prescribe a  standard  of performance
 which is intended to apply to  that type of emission source.
 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 existing sources that have been modified
 Nitrate: A compound  containing nitrogen which 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 m infants and cows.
 Nitric Oxide (NO): A gas formed by combustion under high temperature and
 high  pressure  in an internal combustion engine  It changes into nitrogen
 dioxide in the ambient air and contributes to photochemical smog
 Nitrification: The process whereby ammonia  in wastewater is oxidized to
 nitrite and then to nitrate by bacterial or chemical reactions.
 Nitrilotriacetic Acid (NTA): A compound being used to  replace phosphates in
 detergents.
 Nitrite: 1. An intermediate m the process of nitrification  2. Nitious oxide salts
 used in food preservation
 Nitrogen Dioxide (NO2): The result of nitric oxide combining with oxygen in
 the atmosphere A major  component of photochemical smog.
Nitrogenous Wastes: Animal or vegetable residues that contain significant
amounts of nitrogen.
Nitrogen Oxide (NOx): Product of combustion from transportation and sta-
tionary  sources and major a contributor to the formation of ozone in the
troposphere and acid deposition.
Non-Attainment Area: Geographic area which does not meet one or more of
the National Ambient Air Quality Standards for the criteria pollutants desig-
nated in the Clean Air Act
Non-Community Water System: A public water system that is not a communi-
ty water system, e g., the water supply at a camp site or national park.
Non-Conventional Pollutant: Any pollutant which is not a statutonly listed or
which is poorly understood by the scientific community.
Non-ionizing Electromagnetic Radiation: 1. 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-Point Source: Pollution sources which are diffuse  and do not have a
single point of origin or are not introduced into a  receiving stream from a
specific outlet. The pollutants are generally carried off the  land by stormwater
runoff The commonly used categories for non-point sources are' agriculture,
forestry, urban, mining, construction, dams and channels, land disposal, and
saltwater intrusion
Nuclear Power Plant: A facility that converts atomic energy into usable power;
heat produced by  a reactor makes steam to drive turbines which produce
electricity.
Nuclear Winter: Prediction by some scientists that smoke and debris  rising
from massive fires resulting from a nuclear war could enter the atmosphere
and block out sunlight  for weeks or months  The scientists making this
prediction project a cooling of the earth's surface, and  changes in climate
which could, for example,  negatively effect world agricultural and weather
patterns.
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.

o
 Off-Site Facility. A hazardous waste treatment, storage or disposal area that
is located at a place away from  the generating site
Oil Spill: An accidental or intentional discharge of oil which reaches bodies of
water. Can be controlled  by chemical  dispersion, combustion, mechanical
containment, and/or adsorption.
Oil Fingerprinting: A method that identifies sources of oil and allows spills to
be traced back to their source.
Oligotrophic Lakes: Deep clear lakes with low nutrient supplies. They contain
little organic matter and have a high dissolved-oxygen level.
Oncogenic: A substance that causes tumors, whether benign or malignant.
On-Scene Coordinator (OSC): The predesignated EPA, Coast Guard, or De-
partment of Defense official who coordinates and directs  Superfund removal
actions or Clean Water Act oil-or hazardous-spill corrective actions,
On-Site Facility: A hazardous waste treatment, storage or disposal area  that is
located on the generating site
Opacity: The amount of light obscured by particulate pollution in the air; clear
window glass has a zero opacity, a brick wall has 100 percent opacity Opacity
is used as an indicator of changes in performance of particulate matter  pollu-
tion control systems.
Open Burning: Uncontrolled fires in an open dump
Open Dump: An uncovered site used for disposal of waste without environ-
mental controls. (See: dump.)
Operable Unit: Term for each of a number of separate activities undertaken as
part of a Superfund site cleanup. A typical operable unit  would be removing
drums and tanks from the surface of a site
Operation And Maintenance: 1  Activities conducted at  a site after a Super-
fund site action is completed to ensure that the action is effective and operating
properly.  2. Actions taken after construction to assure that facilities con-
structed to treat waste water will be properly operated,  maintained,and man-
aged  to achieve efficiency levels and prescribed effluent limitations in an
optimum manner
Organic: 1. Referring to or derived from living organisms  2 Ir chemistry, any
compound containing carbon
12

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Organic Chemicals/Compounds: Animal or plant-produced substances con-
taining mainly carbon, hydrogen, and oxygen
Organic Matter: Carbonaceous waste contained in plant or animal matter and
originating from domestic or industrial sources
Organism: Any living thing.
Organophosphates: Pesticide chemicals  that contain phosphorus, used to
control insects They are short-lived, but some can be toxic when first applied.
Organotins: Chemical compounds used in anti-foulant paints to protect the
hulls of boats and ships, buoys, and dock pilings from marine organisms such
as barnacles.
Osmosis: The tendency of a fluid to pass through a permeable membrane such
as the wall of a living cell into a less concentrated solution so as to equalize the
concentrations on both sides of  the membrane.
Outfall: The place where an effluent is discharged into receiving waters
Overburden: The rock and soil cleared away before mining.
Overfire Air: Air forced into the top of an incinerator or boiler to fan the
flames.
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,
the contaminants are removed and the water is collected at the bottom of the
slope for reuse.
Overturn: The period of mixing (turnover), by top to bottom circulation, of
previously stratified water masses. This  phenomenon may occur in spring
and/or fall, or after storms. It results in a uniformity of chemical and physical
properties of the water at all depths.
Oxidant: A substance containing oxygen that reacts chemically m air to pro-
duce a new substance. The primary ingredient of photochemical smog
Oxidation: 1. The addition of oxygen which  breaks down organic waste or
chemicals such as cyanides, phenols, and organic sulfur compounds in sew-
age by bacterial and chemical means. 2.  Oxygen combining with other ele-
ments. 3.  The process in chemistry whereby electrons are removed from a
molecule.
Oxidation Pond: A man-made lake or body of water m which waste is con-
sumed by bacteria. It is used most frequently with other waste-treatment
processes. An oxidation pond is basically the same as a sewage lagoon
Oxygenated Solvent:  An organic solvent containing oxygen as part  of the
molecular structure. Alcohols and ketones are oxygenated compounds often
used as paint solvents
Ozonator: A device that adds ozone to water.
Ozone (O3): Found in two layers of the atmosphere, the stratosphere and the
troposphere. In the stratosphere  (the  atmospheric layer  beginning 7 to 10
miles above the earth's surface) ozone is a form of oxygen found naturally
which provides a protective layer shielding the earth from ultraviolet radia-
tion's harmful health effects on humans and the environment In the tropos-
phere (the layer extending up 7 to 10 miles from the earth's surface), ozone is a
chemical oxidant and major component of photochemical smog. Ozone can
seriously affect the human respiratory system and is one of the most prevalent
and widespread of all the cntena 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
atmosphere 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  biological life This destruction
of ozone is caused by the breakdown of certain chlorine  and/or-bromme
containing compounds (chlorofluorocarbons  or halons) which break  down
when they reach the stratosphere and catalytically destroy ozone molecules
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.
Pandemic: Widespread throughout an area, nation or the world
Part A Permit, Part B Permit: (See Interim Permit Status.)
Paraquat: A standard herbicide used  to kill various types of crops, including
marijuana.
Particulates: Fine liquid or solid particles such as dust, smoke, mist, fumes, or
smog, found in air or emissions
 Particulate Loading: The mass of particulates per unit volume of air or water.
 Pathogenic: Capable of causing disease.
 Pathogens: Microorganisms that can cause disease in other organisms or in
 humans, animals and plants  They may be bacteria, viruses, or parasites and
 are found in sewage, in runoff from animal farms or rural areas populated with
 domestic and/or wild animals,  and in water used for swimming. Fish and
 shellfish contaminated by pathogens, or the contaminated water itself, can
 cause serious illnesses.
 PCBs: A group of toxic, persistent chemicals (polychlorinated biphenyls) used
 in transformers  and capacitators for insulating purposes and in gas pipeline
 systems as a lubricant Further sale of new use was banned by law in  1979
 Percolation:  The movement  of water downward and radially through  the
 sub-surface soil  layers, usually continuing downward to the ground water.
 Permeability: The rate at which liquids pass through soil or other materials in a
 specified direction.
 Permit: An authorization, license,  or equivalent control document issued by
 EPA or an approved state agency  to implement the requirements of an en-
 vironmental 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, once introduced into the
 environment, stays there. 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 that remain in the environment after a growing season.
 Pest: An insect, rodent, nematode, fungus,  weed or other form of terrestrial or
 aquatic plant or animal life or virus, bacterial or  microorganism  that is in-
 jurious to health or the environment.

 Pesticide: Substance or mixture of substances  intended for preventing,  de-
 stroying, repelling,  or mitigating any pest.  Also, any substance or mixture of
 substances intended for use as a  plant regulator, defoliant,  or  desiccant.
 Pesticides can accumulate in the food chain and/or contaminate the environ-
 ment if misused.

 Pesticide Tolerance: The amount of pesticide residue allowed by law to remain
 in or on a harvested crop. By using various safety factors, EPA sets these levels
 well below the point where the chemicals might be harmful to consumers.
 pH:  A measure of the acidity or alkalinity  of a  liquid or solid material
 Phenols: Organic compounds that are by products of  petroleum refining,
 tanning, and textile, dye, and resin manufacturing. Low concentrations cause
 taste and odor problems in water; higher concentrations can kill aquatic life
 and  humans.
 Pheromone: Hormonal chemical produced  by female of a species to attract a
 mate.
 Phosphates: Certain chemical compounds  containing phosphorus
 Phosphorus:  An essential chemical food element that can contribute to the
 eutrophication of lakes and other water bodies. Increased phosphorus levels
 result from discharge of phosphorus-containing materials into surface waters.
 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
 pollutants emitted from different sources.
 Photosynthesis: The manufacture by plants of carbohydrates and oxygen from
 carbon dioxide and water in the presence of chlorophyll,  using sunlight as an
 energy source.
 Physical and Chemical  Treatment: Processes  generally used in large-scale
 waste-water treatment facilities. Physical processes may involve air-stripping
 or filtration. Chemical treatment includes coagulation, chlorination, or ozone
 addition. The term can also refer to treatment processes, treatment of toxic
 materials in surface waters 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
 Phytotoxic: Something that harms plants.
Picocurie: Measurement of radioactivity A  picocune is one  million millionth,
 or a tnllionth, of  a curie,  and represents about 2  2 radioactive particle disinte-
grations per minute.
Picocuries Per Liter pCi/L): A unit  of measure used for expressing levels of
radon gas (See picocune )
                                                                                                                                          13

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Pig: A container, usually lead, used to ship or store radioactive materials.
Pile: 1. The fuel element in a nuclear reactor. 2. A heap of waste
Plankton: Tiny plants and animals that live in water.
Plasmid: A circular piece of DNA that exists apart from the chromosome and
replicates independently of it. Bacterial plasmids carry information that ren-
ders the bacteria resistant to antibiotics. Plasmids are often used in genetic
engineering to carry desired genes into organisms.
Plastics: Non-metallic compounds that result from a chemical reaction, and
are molded or formed into rigid or pliable construction  materials or fabrics.
Plugging: 1. The 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. 2.
Stopping a leak or sealing off a pipe or hose.
Plume: 1. A visible or measurable discharge of a contaminant from a given
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 measurable and potentially harmful
radiation leaking from a damaged reactor. 3. The distance from a toxic release
considered dangerous for those exposed to the leaking fumes
Plutonium: A radioactive metallic element similar chemically to uranium.
Point Source: A stationery location or fixed facility from which pollutants are
discharged or emitted. Also, any single identifiable source of pollution, e g., a
pipe,  ditch, ship, ore pit, factory smokestack.
Pollen: 1. A fine dust produced by plants. 2.The fertilizing element of flower-
ing plants. 3. A natural or background air pollutant.
Pollutant: Generally, any substance introduced into the environment that
adversely affects the usefulness of a resource.
Pollutant Standard Index (PSD:  Measure  of adverse  health effects of air
pollution levels in major cities.
Pollution: Generally, the presence of matter or energy whose nature, location
or quantity produces undesired environmental effects. Under the Clean Water
Act, for example, the term is  defined as the  man-made or man-induced
alteration of the physical, biological, and radiological integrity of water.
Polyelectrolytes: Synthetic chemicals that help solids to clump during sewage
treatment.
Polymer: Basic molecular ingredients in plastic.
Polyvinyl Chloride (PVC): A tough, environmentally  indestructible plastic
that releases hydrochloric acid when burned.
Population: A group of interbreeding organisms of the same kind occupying a
particular space. Generically, the number of humans or other living creatures
in a designated area.
Post-Closure: The time period following the shutdown of a waste manage-
ment or manufacturing facility. For monitoring purposes, this is often consid-
ered to be 30 years.
Potable Water: Water that is safe for drinking and cooking.
Potentially Responsible Party (PRP): Any  individual or  company—including
owners, operators, transporters or generators—potentially responsible for, or
contributing to, the contamination problems at a Superfund site. Whenever
possible, EPA requires PRPs,  through  administrative and legal actions, to
clean up hazardous waste sites they have contaminated.
PPM/ PPB: Parts per million/ parts per  billion, a way of expressing tiny
concentrations of pollutants in air, water,  soil, human tissue, food, or  other
products.
Precipitate: A solid that separates from a solution because of some chemical or
physical change.
Precipitation: Removal of solids from liquid waste so that the hazardous solid
portion can be disposed  of safely; removal of particles from airborne  emis-
sions.
Precipitators: Air pollution control devices that collect particles from an  emis-
sion.
Precursor: In photochemical  terminology, a compound  such as a volatile
organic compound (VOC) that "precedes" an oxidant. Precursors react in
sunlight to form ozone or other photochemical oxidants
Preliminary Assessment: The  process of  collecting and reviewing available
information about a known or suspected  waste site or  release
Pressure Sewers: A system of pipes in which  water, wastewater,  or  other
liquid is transported to a higher elevation by use of pumping force
Pretreatment:  Processes  used to  reduce, eliminate,  or alter the nature of
wastewater pollutants from non-domestic  sources before they are discharged
into publicly owned treatment works.
Prevention: Measures taken to minimize the release of wastes to the environ-
ment.
Prevention of Significant Deterioration (PSD): EPA program in which state
and/or federal permits are required that are intended to restrict emissions for
new or modified sources in places where air quality is already better than
required to meet primary and secondary ambient  air quality standards.
Primary Drinking Water Regulation:  Applies to public water systems and
specifies a contaminant level, which, in the judgement of the EPA Administra-
tor, will have no adverse effect on human health.
Primary Waste Treatment:  First steps in wastewater treatment; screens and
sedimentation tanks are used to remove most materials that floats or will
settle. Primary  treatment results in the removal of  about  30  percent of
carbonaceous biochemical oxygen demand from domestic sewage.
Process Weight: Total weight of all materials, including fuel,  used  in a
manufacturing process. It is used to calculate the allowable particulate emis-
sion rate from the process.
Proteins: Complex nitrogenous organic compounds of high molecular weight
that contain amino acids as their basic unit and are essential for growth and
repair of animal tissue. Many proteins are enzymes.
Protoplast: A membrane-bound cell from which the outer cell wall has been
partially or completely removed. The term often is applied to plant cells.
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:  A waste-treatment works owned  by a
state, unit of local government, or Indian tribe,  usually designed to treat
domestic wastewaters.
Pumping Station:  Mechanical devices installed in sewer or water systems or
other liquid-carrying pipelines that move the liquids to a higher level.
Putrescible:  Able to rot quickly enough to cause odors and attract flies.
Pyrolysis:  Decomposition of a chemical by extreme heat.

Q
Quality Assurance/Quality Control: A system of procedures, checks, audits,
and corrective actions to ensure that all EPA research design and performance,
environmental monitoring and sampling, and other technical and reporting
activities are of the highest achievable quality.
Quench Tank:   A water-filled tank used  to cool incinerator residues or hot
materials during industrial  processes.
RAD (Radiation Absorbed Dose): A unit of absorbed dose of radiation. One
RAD of absorbed dose is equal to .01 joules per kilogram.
Radiation:  Any form of energy propagated as rays, waves, or streams of
energetic particles. The term is frequently used in relation to the emission of
rays from the nucleus of an atom.
Radiation  Standards:  Regulations that set maximum exposure limits for
protection  of the public from radioactive materials.
Radioactive Substances: Substances that emit radiation.
Radiobiology:  The study radiation effects on living things
Radio Frequency Radiation:  (See Non-ionizing Radiation.)
Radionuclide: Radioactive element characterized according to its atomic mass
and atomic number which can be man-made or naturally occurring. Radioiso-
topes can have a long life as soil or water pollutants, and are believed to have
potentially mutagenic effects on the human body
Radius of Vulnerable 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
Radon:  A colorless  naturally occurring, radioactive, inert gaseous element
formed by radioactive decay of radium atoms in soil or rocks
Radon Decay Products:  A term used to refer collectively to the immediate
products of the radon decay chain These include Po-218, Pb-214, Bi-214, and
Po-214, which have an average combined half-life of about 30 minutes

Rasp: A machine that grinds waste into a manageable material and helps
prevent  odor
Raw  Sewage: Untreated wastewater
14

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  easonably Available Control Technology (RACT): The lowest emissions
  mit that a particular source is capable of meeting by the application of control
  ;chnology that is both reasonably available, as well as technologically and
  conomically feasible. RACT is usually applied to existing to existing sources
  i nonattainment areas and most cases  is less stringent than new source
  erformance standards.
  eceiving  Waters:  A river, lake, ocean, stream or other watercourse into
  'hich wastewater or treated effluent is discharged.
  echarge: The process by which water is added to a zone of saturation, usually
  y percolation from the soil surface,  e g., the recharge of an aquifer
  .echarge Area:  A land area in which water reaches to the zone of saturation
  •om surface infiltration, e.g., an area where rainwater soaks through the earth
  ) reach an aquifer.
  .ecombinant Bacteria: A type of microorganism whose genetic makeup has
  een altered by deliberate introduction of new genetic elements The offspring
  f these altered  bacteria also contain these new genetic elements
  .ecombinant DNA (rDNA):  The new DNA that  is formed by combining
  ieces of DNA from different organisms  or cells.
  .ecommended Maximum Contaminant Level (RMCL): The maximum level
  f a contaminant in drinking water at which no known or anticipated adverse
  ffect on human health would occur, and which includes an adequate margin
  f safety. Recommended levels are nonenforceable health goals. (See: max-
  num contaminant level.)
  .econstructed Source: An existing facility in which components are replaced
  a such an extent that the fixed capital cost of the new components exceed 50
  lercent of the capital cost that would be required to construct a comparable
  ntirely new facility. New source performance standards may be applied to
  ources which are reconstructed after the proposal of  the standard if it is
  echnologically and economically feasible to meet the standard.
  ecord of Decision (ROD):  A public document that explains which cleanup
  Iternative(s) will be used at National  Priorities List sites where, under CERC-
  ,A,  Trust Funds pay for the cleanup.
  Recycle/Reuse: The process of minimizing the generation of waste by reco ver-
 ng usable  products that might otherwise become waste. Examples are the
  ecycling of aluminum cans, wastepaper, and bottles.
 led Border: An EPA document that  is undergoing final review before being
 lubmitted for final management decision
 led Tide:  A proliferation of a marine plankton that is toxic and often fatal to
 ish. This natural phenomenon may be stimulated by the addition of nutrients.
 \ tide can be called red, green or brown,  depending on the coloration of the
 slankton.
 leentry Interval: The period of time immediately following the application of
 i pesticide during which unprotected workers should not enter a field.
 Refuse:  (See: solid waste.)
 Refuse Reclamation:  Conversion of solid waste into useful products, e g.,
 :omposting organic wastes to make soil conditioners or separating aluminum
 md  other metals for melting and recycling
 Regeneration: Manipulation of individual cells or  masses of cells to cause
 :hem to develop into  whole plants.
 Regional Response Team (RRT): Representatives 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 Superfund response action.
 Registrant:  Any manufacturer or formulator 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 in intra- or  inter-state commerce  The product must be reg-
 istered under the Federal Insecticide,  Fungicide, and Rodenticide Act. EPA is
 responsible for registration (pre-market licensing) of pesticides on the basis of
 data demonstrating that they will not cause unreasonable adverse effects on
 human health or the  environment when  used according to approved label
 directions
 Registration Standards: Published reviews of all the data available on pesti-
 cide  active  ingredients
 REM (Roentgen  Equivalent Man): The unit of dose  equivalent from ionizing
radiation to the  human body,  used to measure the amount of radiation to
which  a person or a part of a human has been exposed.
Remedial Action (RA): The actual construction or implementation phase of a
Superfund  site cleanup that follows remedial design.
Remedial Design: A  phase of remedial  action that follows the remedial
investigation/feasibility study  and  includes development of engineering
drawings and specifications for a site cleanup
Remedial Investigation: An in-depth study designed to gather the data neces-
sary to determine the nature and extent of contamination at a Superfund site;
establish criteria for cleaning up the site; identify preliminary alternatives for
remedial actions; and support the technical and cost analyses of the alterna-
tives. 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 remedial action at a site.
Remedial Response: A 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.
Removal  Action: Short-term immediate actions taken to address releases of
hazardous substances that require expedited response. (See: cleanup.)
Reportable Quantity (RQ):   The quantity of a  hazardous substance that
triggers reports under CERCLA. If a substance is released in amounts exceed-
ing its RQ, the release must be reported to the National Response Center, the
SERC, and community emergency coordinators for areas likely to be affected.
Reregistration: The reevaluation and relicensing of existing pesticides origi-
nally registered prior to current scientific and regulatory standards  EPA
reregisters pesticides through its Registration Standards Program
Reservoir: Any natural or artificial holding area  used to store, regulate, or
control water.
Residual: Amount of a pollutant remaining in the environment after a natural
or technological process has taken place, e.g., the sludge remaining after
initial wastewater treatment, or particulates  remaining in air  after the air
passes through a scrubbing  or process.
Resistance: For plants and animals, the ability to withstand poor environmen-
tal conditions and/or attacks by chemicals or disease. The ability may be inborn
or developed.
Resource: A person, thing,  or action needed for living or  to improve the
quality of life.
Response Action: A CERCLA-authonzed action involving either a short-term
removal action or a long-term removal response that may  include but is not
limited to: removing hazardous materials from' a site to an EPA-approved
hazardous waste facility for treatment, containment, or destruction; contain-
ing the  waste safely on-site; destroying or treating the waste  on-site; and
identifying and  removing the source of ground-water contamination and
halting further migration of  contaminants (See: cleanup.)
Resource Recovery: The process of obtaining matter or energy from materials
formerly discarded.
Restoration: Measures taken to return a site to pre-violation conditions.
Restricted Use: When a pesticide is registered, some or all  of its  uses may be
classified (under FIFRA regulations) for restricted use if the pesticide requires
special handling because of its toxicity. Restricted-use pesticides  may be
applied  only by  trained,  certified applicators or those under their  direct
supervision.
Restriction Enzymes: Enzymes that recognize certain specific regions of a long
DNA molecule and then cut the DNA into smaller pieces.
Reverse Osmosis: A water treatment process used in small 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 now being developed
Ribonucleic Acid (RNA):  A  molecule that carries the  genetic message from
DNA to a cell's protein-producing mechanisms,  similar to, but chemically
different from, DNA
Ringlemann Chart: A series of shaded illustrations  used to measure the
opacity of air pollution emissions. The chart ranges from light grey through
black and is used to set and enforce emissions standards.
Riparian Habitat: Areas adjacent to rivers and  streams  that have a high
density, diversity, and productivity of plant and animal species relative to
nearby uplands.
Riparian Rights: Entitlement of a land owner to the water on or bordering his
property,  including the right to prevent diversion or misuse of upstream
waters. Generally, a matter of state law.
Risk Assessment: The qualitative and quantitative evaluation performed in an
effort to define the risk posed to human health and/or the environment by the
presence or potential presence and/or use  of specific pollutants.
Risk Communication: The exchange of information about health or environ-
mental risks between risk assessors, risk managers, the general public, news
media, interest groups, etc.

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Risk Management: The process of evaluating alternative regulatory and non-
regulatory responses to risk and selecting among them The selection process
necessarily requires the consideration of legal, economic and social factors.
River Basin: The land area drained by a river and its tributaries.
Rodenticide: A chemical or agent used to destroy rats or other rodent pests, or
to prevent them from damaging food, crops, etc.
Rough Fish: Those fish, not prized for eating, such as gar and suckers. Most
are more tolerant of changing environmental conditions than game species
Rubbish: Solid waste, excluding food waste and ashes,  from homes,  in-
stitutions, and work-places.
Run-Off: That part of precipitation, snow melt, or irrigation water that runs off
the land into streams or other surface-water. It can carry pollutants from the air
and land into the receiving waters.
Salinity: The degree of salt in water
Salts: Minerals that water picks up as it passes through the air, over and under
the ground, and as it is used by households and industry.
Salt Water Intrusion: The invasion of fresh surface or ground water by salt
water, if the salt water comes  from  the ocean it may be called sea water
intrusion.
Salvage: The utilization of waste materials.
Sanitation: Control of physical factors in the human environment that could
harm development, health, or survival.
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 landfill, sanitary.)
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,
operation and maintenance of a public water system to evaluate the adequacy
of those elements for producing and  distributing safe drinking water.
Saturated Zone: A subsurface area in which all pores and cracks are filled with
water under pressure equal to or greater than that of the atmosphere.
Scrap: Materials  discarded from manufacturing operations that may be suit-
able for reprocessing.
Screening: Use of  screens to remove coarse floating and suspended solids
from  sewage.
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:  Unenforceable regulations  which
apply to public water systems and which specify the maximum contamination
levels which, in the judgement of EPA, are required to protect the  public
welfare  These regulations  apply to  any contaminants  that may adversely
affect the odor or  appearance of such  water and consequently may cause
people served by the system to discontinue its use.
Secondary Treatment: The second step  in most publicly owned  waste treat-
ment systems in  which bacteria consume the organic parts of the waste It is
accomplished 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, tertiary treatment )
Secure Chemical: (See  landfills )
Secure Maximum Contaminant Level: Maximum permissible level of a con-
taminant in water which is delivered to the free flowing outlet of the ultimate
user of a water supply, the consumer,  or of contamination resulting from
corrosion of piping and plumbing caused  by water quality
Sediments: Soil, sand, and minerals washed from land into water usually after
ram They pile up in reservoirs, rivers and harbors, destroying  fish-nesting
areas and holes  of water animals, and  clouding the water so that needed
sunlight might not reach aquatic plants Careless farming, mining, and build-
ing activities will expose sediment materials, allowing them to be washed off
the land after rainfalls.
Sedimentation: Letting solids settle  out of wastewater by gravity during
waste water treatment
Sedimentation Tanks: Holding  areas for wastewater where floating wastes
are skimmed off and settled solids are reimned  for disposal.
Selective Pesticide: A chemical designed to affect only certain types of pests,
leaving other plants and animals unharmed
Semi-Confined Aquifer: An aquifer that is partially confined by a soil layer (or
layers) of low permeability through which recharge and discharge can occur
Senescence: Term for the aging process. Sometimes used to describe lakes o
other bodies of water in advanced stages of eutrophication
Septic Tank: An underground storage tank for wastes from homes having n<
sewer line to a treatment plant  The waste goes directly from the home to th
tank, where the organic waste is decomposed by bacteria and  the sludg
settles  to the bottom  The effluent flows out of the tank into the grouni
through drains; the sludge is pumped out  periodically
Service Connector: The pipe that carries tap water from the public water mah
to a building.
Settleable Solids: Material heavy enough to sink to the bottom of a wastewate
treatment tank.
Settling Chamber: A series of screens placed m the way of flue gases to slo\
the stream of air, thus helping gravity to pull particles out of the emission int'
a collection area.
Settling Tank: A holding area for wastewater, where heavier particles sink tt
the bottom for removal and disposal.
Sewage: The waste and wastewater produced by residential and commercia
establishments and discharged into sewers.
Sewage Lagoon: (See. lagoon.)
Sewage Sludge: Sludge produced at a Publicly Owned Tieatment Works, th
disposal of which is regulated under the Clean Water Act
Sewer: A channel or conduit that carries wastewater and stormwater runof
from the source to a treatment plant or receiving stream. Sanitary sewers carr
household, industrial, and commercial waste. Storm sewers carry runoff fror
ram or snow Combined sewers are used for both purposes
Sewerage: The entire system of sewage collection, treatment, and disposal
Shotgun: Non-scientific term for the process of breaking up the DNA derive^
from an organism and then moving  each  separate and  unidentified DM/
fragment into a bacterium.
Signal Words: The words used  on  a pesticide label—Danger, Warning
Caution—to indicate the level of toxicity of the chemicals.
Significant Deterioration: Pollution resulting from a new source in previous!
"clean" areas. (See:  prevention  of significant deterioration )
Significant  Municipal Facilities:  Those publicly owned sewage treatmen
plants  that discharge a million gallons per day or more and  are therefor
considered by states to have the potential for substantial effect on the quality o
receiving waters.
Significant Violations: Violations by point source dischargers of sufficien
magnitude and/or duration to be a regulatory priority
Silt: Fine particles of sand or rock that can be picked up by the  air or water am
deposited as sediment.
Silviculture: Management of forest land for timber Sometimes contributes t
water pollution, as in clear-cutting
Sinking: Controlling oil spills by using an agent to trap the oil and sink it to th
bottom of the body of water where the agent  and the oil are biodegraded
Site Inspection: The collection of  information from a Superfund site to de
termine the extent and severity of hazards posed by the site. It follows and i
more extensive than a preliminary assessment  The purpose is to  gathe
information necessary to score the site, using the Hazard Ranking System, an<
to determine if the site presents an immediate threat that requires promp
removal action.
Siting: The  process of choosing a  location  for a  facility.
Skimming:  Using a machine to remove oil or scum  from the surface of th
water.
Slow Sand  Filtration: Treatment  process  involving  passage of raw wate
through a bed of sand at low velocity which results in the substantial remova
of chemical and biological contaminants,
Sludge: A semi-solid residue from any of a number of air or water treatmen
processes. Sludge can be a hazardous waste
Slurry: A watery mixture of insoluble matter that results from some pollutioi
control techniques
Smelter: A facility that melts or fuses ore, often with an accompanying chem
ical change, to separate the metal  Emissions are known to cause pollution
Smelting is the process involved
16

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  nog: Air pollution associated with oxidants. (See. photochemical smog )
  noke: Particles suspended in air after incomplete combustion of materials
  >ft Detergents: Cleaning agents that break down in nature.
  >ft Water: Any water that is not "hard," i e , does not contain a significant
  nount of dissolved minerals such as salts containing calcium or magnesium
  >il Adsorption Field: A sub-surface area containing a trench or bed with
  ;an stones and a system of distribution piping through which treated sewage
  ay seep into the surrounding soil for further treatment and disposal
  >il Conditioner: An organic material like humus or compost that helps  soil
  isorb water, build a bacterial community,  and distribute nutrients and
  inerals.
  )il Gas: Gaseous elements and compounds that occur in the small spaces
  •tween particles of the earth and soil, Such gases can move through or leave
  e soil or rock, depending on changes in pressure.
  jlder: A metallic compound used to seal  the joints between pipes. Until
  cently, most solder ocontamed 50 percent lead.
  jle Source Aquifer: An aquifer that supplies 50 percent or  more of  the
  •inking water of an area.
  jlid Waste: Non-liquid., non-soluble materials ranging from municipal gar-
  ige to industrial wastes that contain complex, and  sometimes hazardous,
  ibstances  Solid wastes also include sewage sludge, agricultural  refuse,
  emohhon wastes, and mining residues. Technically, solid waste also refers to
  }uids and gases in containers.
  olid Waste Disposal: The final placement  of refuse  that is not salvaged or
  •cycled
  olid Waste Management: Supervised handling of waste materials from their
  )urce through recovery processes to  disposal
  olidification and  Stabilization:  Removal  of wastewater from a waste or
  langing it chemically to make the waste less permeable and susceptible to
  ansport by water.
  olvent:  Substance (usually liquid) capable of dissolving or dispersing one or
  lore other substances.
  oot: Carbon dust formed by incomplete combustion.
  orption: The action of soaking up or attracting substances. A process used in
  lany pollution control systems.
  pecial Review: Formerly known as Rebuttable Presumption Against Regis-
  •ation (RPAR), this is the regulatory process through which existing pesti-
  des suspected of posing unreasonable risks to  human health, non-target
  rganisms, or the environment are referred for review by EPA. The  review
  squires  an intensive risk/benefit analysis with opportunity for public com-
  ient If  the risk of any use of a pesticide is found to outweigh social and
  conomic benefits, regulatory actions—ranging from label revisions and use-
 estnction to cancellation or suspended registration—can be initiated.
 ipecies:  A reproductively isolated aggregate of interbreeding populations of
 irgamsms
 ipill Prevention Control and Countermeasures Plan  (SPCC): Plan covering
  le release of hazardous substances as defined in the Clean Water Act
  prawl: Unplanned development of open land
 ipoil: Dirt or rock that has been removed from its original location, destroying
 he composition of the soil in the process, as with strip-mining or dredging
 Stabilization: Conversion of the active organic matter in sludge into inert,
 larmless material.
 Stabilization Ponds: (See. lagoon )
 stable Air: A mass of air that is not moving normally, so that it holds rather
 ban disperses pollutants.
 stack: A chimney or smokestack, a vertical  pipe that  discharges used air
 stack Effect: Used  air, as in  a  chimney, that moves upward because it is
 ivarmer than the surrounding atmosphere
 Stack Gas: (See: flue gas.)
 Stagnation: Lack of motion in a mass of air or water, which tends to hold
 pollutants
Standards: Prescriptive norms which govern action and actual limits  on  the
amount of pollutants or emissions produced  EPA, under most of its responsi-
bilities, establishes minimum standards  States are allowed to be stricter
State Emergency Response Commission (SERC): Commission  apomted by
each state governor according to the  requirements oi SARA Title 111 The
SERC's designate emergency planning  districts, appoint local  emergency-
planning committees, and supervise and coordinate their activities
State Implementation Plans (SIP): EPA-approved state plans for the establish-
ment,  regulation, and enforcement of air pollution standards
Stationary Source: A fixed, non-moving producer of pollution,  mainly power
plants and other facilities using industrial combustion processes.
Sterilization: 1. In pest control, the use of radiation and chemicals to damage
body cells needed for reproduction. 2 The destruction of all living organisms
in water or on the surface of various materials In contrast, disinfection is the
destruction of most living organisms in water or on surfaces.
Storage: Temporary holding of waste pending treatment or dispcsal Storage
methods include containers, tanks, waste piles, and surface impoundments
Storm Sewer: A system of pipes  (separate from sanitary sewers) that carry
only water runoff  from building and land surfaces.
Stratification: Separating into layers.
Stratosphere: The  portion of the atmosphere that is 10-to-25 miles above the
earth's surface.
Strip-Cropping: Growing crops in a systematic arrangement of strips or bands
which serve as barriers to wind and water erosion
Strip-Mining: A process that uses machines to scrape soil or rock away from
mineral deposits just under the earth's surface
Sulfur Dioxide  (SO2). A heavy,  pungent, colorless,  gaseous air pollutant
formed primarily by the combustion of fossil plants.
Sump: A pit or tank that catches  liquid runoff for drainage or disposal
Sump Pump: A mechanism for removing water or wastewater from a sump or
wet well.
Superfund: The program operated under the legislative authority of CERCLA
and SARA that  funds and carries out the EPA solid waste emergency and
long-term removal remedial activities. These activities include establishing the
National Priorities List, investigating sites for inclusion on the list, determin-
ing their priority level on the list, and  conducting and/or supervising the
ultimately determined cleanup and other remedial actions
Surface Impoundment: Treatment, storage, or disposal of liquid hazardous
wastes in ponds
Surface Water: All water naturally open to  the atmosphere (rivers, lakes,
reservoirs,  streams, impoundments, seas, estuaries, etc.) and  all  springs,
wells,  or other collectors which are directly influenced by surface water
Surfactant: A surface-active agent used in detergents to cause lathering.
Surveillance System: A series of monitoring  devices designed to determine
environmental quality.
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
conventional means (See: Total Suspended Solids.)
Suspension: The act of suspending the use of a pesticide when EPA deems it
necessary to do  so in order to prevent an imminent hazard resulting from
continued use of the pesticide. An emergency  suspension takes effect im-
mediately; under an ordinary suspension a registrant can request a hearing
before the suspension goes into effect. Such a hearing process might take six
months.
Suspension Culture: Individual cells or  small clumps of cells  growing in a
liquid  nutrient medium.
Swamp: A type of  wetland that is dominated by woody vegetation and does
not accumulate appreciable peat deposits. Swamps may be fresh or salt water
and tidal or non-tidal. (See Wetlands.)
Synergism: The  cooperative interaction  of two  or more chemicals or other
phenomena producing a greater total effect than the sum of their individual
effects.
Synthetic Organic Chemicals (SOCs): Man-made organic  chemicals Some
SOCs are volatile, others tend to stay dissolved in water rather than evaporate
out of  it.
Systemic Pesticide: A chemical that is taken up from the ground or absorbed
through the surface and carried through the system of the organism being
protected, making the organism toxic to pests
Tailings: Residue of raw materials or waste separated out during the process-
ing of crops or mineral ores
TBT Paints (Trybutilin): (See: organotms )
Technology-Based Standards: Effluent limitations applicable to direct and
indirect sources which are developed on a category-by-category basis using
statutory factors,  not including water-quality effects
                                                                                                                                            17

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Teratogen: Substance that causes malformation or serious deviation  from
normal development of embryos and fetuses.
Terracing: Diking, built along the contour of sloping agricultural land, that
holds runoff and sediment to reduce erosion.
Tertiary Treatment: Advanced cleaning of wastewater that goes beyond the
secondary or biological stage. It removes nutrients such as phosphorus and
nitrogen and most BOD and suspended solids.
Thermal Pollution: Discharge of heated water from industrial processes that
can affect the life processes of aquatic organisms.
Threshold Limit Value (TLV): Represents the air concentrations of chemical
substances to which it is believed that workers may be daily exposed without
adverse effect.
Threshold Planning Quantity: A quantity 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
emergency planning under SARA Title III.
Tidal Marsh: Low, flat marshlands traversed by channels and tidal hollows
and subject to tidal inundation; normally, the only vegetation  present are
salt-tolerant bushes and grasses. (See wetlands.)
Tolerances: The permissible residue levels for pesticides in raw agricultural
produce and processed foods. Whenever a pesticide 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
Topography: The physical features of a surface area including  relative eleva-
tions and the position of natural and man-made features.
Total Suspended  Solids (TSS):  A  measure of the  suspended  solids in
wastewater, effluent, or water bodies, determined by using tests for "total
suspended non-filterable solids." (See: suspended solids.)
Toxic: Harmful to living organisms.
Toxic Pollutants: Materials contaminating the environment that cause death,
disease, birth defects in organisms that ingest or absorb them. The quantities
and length of exposure necessary to cause these effects can vary widely.
Toxic Chemical Release Form: Information form required to be submitted by
facilities that manufacture,  process,  or use (in quantities above a  specific
amount) chemicals listed under SARA Title  III.
Toxic Cloud: Airborne mass of  gases, vapors, fumes, or aerosols containing
toxic materials.
Toxic Substance: A chemical or mixture that may present an unreasonable risk
of injury to health or the environment.
Toxicant: A poisonous agent that kills or injures animal or plant life.
Toxicity: The degree of danger posed by a substance to animal or plant life.
(See: acute, chronic toxicity.)
Toxicology: The science and study of poisons control.
Transformation: The process of placing new genes into a host cell,  thereby
inducing the host cell to  exhibit functions encoded by the DNA.
Transpiration: The process by which water vapor is lost to the  atmosphere
from living plants. The term can also be applied to the quantity of water thus
dissipated.
Trash-to-Energy Plan: A plan for putting waste back to work by burning trash
to produce energy.
Treatment, Storage, and Disposal Facility: Site where a hazardous substance
is treated, stored, or disposed. TSD facilities are regulated by EPA and states
under RCRA
Trichloroethylene TCE): A stable, low-boiling colorless liquid, toxic by inhala-
tion. TCE is used as a solvent, metal degreasing agent, and in other industrial
applications.
Trickling Filter: A coarse, biological treatment system in which wastewater is
trickled over a bed of stones or other material covered with bacterial growth.
The bacteria break down the
Trihalomethane (THM):  One of a family of organic compounds, named as
derivatives of methane. THM's are generally the by-product from chlonnation
of drinking water that contains  organic material.
Troposphere: The lower atmosphere, the portion of the atmosphere between
seven and ten miles from the Earth's surface where clouds are formed.
Trust Fund (CERCLA): A fund set up under the Comprehensive Environmen-
tal 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.
Tundra: A type of 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 very wet  (See: wetlands.)
Turbidimeter: A device that measures the amount of suspended solids in a
liquid
Turbidity: 1.  Haziness in air caused by the presence of particles and pollut-
ants. 2. A similar cloudy condition in water due to suspended silt or organic
matter.

u

Ultra Clean Coal (UCC): Coal that has been washed, ground into fine parti-
cles, then chemically treated to remove sulfur, ash,  silicone, and other sub-
stances; usually briquetted and coated with a sealant made from coal.
Ultraviolet Rays: Radiation from the  sun that can be useful or potentially
harmful.  UV rays from one part of the spectrum enhance plant life and are
useful in some medical and dental procedures; UV rays from other parts of the
spectrum to which humans are exposed (e.g., while getting a sun tan) can
cause skin cancer or other tissue damage. The ozone layer in the atmosphere
provides a protective shield that limits the amount of ultraviolet rays that reach
the Earth's surface.
Underground Injection Control (UIC): The program under the Safe Drinking
Water Act that regulates the use of wells to pump fluids into the ground.
Underground Sources of Drinking Water: As defined in the UIC program,
this terms refers to aquifers that are currently being used as a  source of
drinking water, and those that are capable of supplying a public water system.
They have a total dissolved solids content of 10,000 milligrams per liter or less,
and are not "exempted aquifers." (See. exempted aquifer.)
Underground Storage Tank: A tank located all or partially under ground that
is designed to hold gasoline or other  petroleum products or chemical solu-
tions.
Unsaturated Zone: The area above the water table where the soil pores are not
fully saturated, although some water  may be present
Uranium: A radioactive heavy metal element used in nuclear reactors and the
production of nuclear weapons. Term refers usually to U-238, the most abun-
dant radium isotope, although a small percentage of naturally-occurring ura-
nium is U-235.
Urban Runoff: Stormwater from city  streets and adjacent domestic or com-
mercial properties that may carry pollutants of various kinds into the  sewer
systems and/or receiving waters.
 Vaccine: Dead or partial or modified antigen used to induce immunity to
 certain infectious diseases.
 Vapor: The gaseous phase of substances that are liquid or solid at atmospheric
 temperature and pressure, e.g., steam
 Vapor Capture System: Any combination of hoods and ventilation system that
 captures or contains organic vapors in order that they may be directed to an
 abatement or recovery device.
 Vapor Dispersion: The movement of vapor clouds in air due to wind, gravity
 spreading, and mixing.
 Vapor Plumes: Flue gases that are visible because they contain water droplets
 Vaporization: The change of a substance from a liquid to a gas
 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 An
 object that is used to transport genes into a host cell (vectors can be plasmids,
 viruses, or other bacteria). A  gene is placed in the vector; the vector then
 "infects" the bacterium.
 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 con-
 taminated air outward.
 Vinyl Chloride: A chemical compound, used in producing some plastics, that
 is believed to be carcogenic.
 Virus: The smallest form of microorganisms capable of causing disease
 Volatile: Description of any substance that evaporates readily
18

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Volatile Organic Compound (VOC): Any organic compound which partici-
pates in atmospheric photochemical reactions except for those designated by
the EPA Administrator as having negligible photochemical reactivity
Volatile Synthetic Organic Chemicals: Chemicals that tend to volatilize or
evaporate from water.
Vulnerability Analysis: Assessment of elements in the community that are
susceptible to damage should a release of hazardous materials occur
Vulnerable Zone:  An area over which the airborne concentration of a chem-
ical involved in an accidental release 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 habitation
Waste Load Allocation: 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.
Waste Treatment Stream: The continuous movement of waste from generator
to treater and disposer.
Waste Treatment Plant: A facility containing a series of tanks, screens, filters
and other processes by which pollutants are removed from water.
Wastewater: The spent or used water from individual homes, a community, a
farm, or an industry that contains dissolved or suspended matter.
Wastewater Operations and Maintenance: Actions taken after construction to
assure that facilities constructed to treat wastewater will be properly operated,
maintained, and managed to achieve efficiency levels and prescribed effluent
levels in an optimum manner.
Water Pollution: The presence in water of enough harmful or objectionable
material to damage the water's quality.
Water Quality Criteria: Specific levels of water quality which, if reached, are
expected to render a body of water suitable for its designated use The criteria
are based on specific levels of pollutants that would make the water harmful if
used for drinking, swimming, farming, fish production, or industrial proc-
esses.
Water Quality Standards: State-adopted and EPA-approved  ambient stan-
dards for water bodies. The standards cover the use of the water body and the
water quality criteria which must be met to protect the designated use or uses.
Watershed: The land area that drains into a stream
Water Supplier: A person 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 Solubility: The maximum concentration of a chemical compound
which can result when it is dissolved in water If a substance is water soluble it
can very readily disperse through the environment.
Water Table: The level of ground water.
Well: A bored, drilled, or driven shaft, or a dug hole, whose depth is greater
than the largest surface dimension and whose purpose is to reach under-
ground water supplies or oil, or to store or bury fluids below ground.
Well Injection: The subsurface emplacement of fluids in a well.
Well Monitoring:  The measurement, by on-site instruments or laboratory
methods, of the quality of water in a well.
Well Plug: A watertight and gaslight seal installed in a bore hole or well to
prevent movement of fluids.
Wetlands: An area that is regularly saturated by surface or ground water and
subsequently is characterized by a prevalence of vegetation that is adapted for
life in saturated  soil conditions.  Examples include: swamps,  bogs,  fens,
marshes, and estuaries.
Wildlife Refuge: An area designated for the protection of wild animals, within
which hunting  and fishing are either prohibited or strictly controlled
Wood-Burning Stove Pollution: Air pollution caused by emissions of particu-
late matter, carbon monoxide,  total suspended particulates, and polycyclic
organic matter from wood-burning stoves.
Working Level (WL): A unit of measure for documenting exposure  to radon
decay products. One working level is equal to approximately 200 picocuries
per liter.
Working Level  Month (WLM): A unit of measure used to determine cumula-
tive exposure to radon.

X,Y,Z
Xenobiotic: Term for non-naturally occurring man-made substances  found in
the environment (i.e., synthetic material solvents, plastics.).
Zooplankton: Tiny aquatic animals eaten by fish.

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Acronyms
AA: Adverse Action
AA: Advices of Allowance
AA: Assistant Administrator
AA: Associate Administrator
AA: Atomic Absorption
AAAS: American  Association for the Advance-
  ment of Science
AAEE: American Academy of Environmental En-
  gineers
AANWR: Alaskan Arctic National Wildlife Refuge
AAP: Affirmative Action Plan
AAP: Affirmative Action Program
AAP: Asbestos Action Program
AARC: Alliance for Acid Rain Control
ABES: Alliance for Balanced Environmental Solu-
  tions
AC: Actual Commitment
AC: Advisory Circular
AC: Alternating Current
A&C: Abatement and Control
ACA: American Conservation Association
ACBM: Asbestos-Containing Building Material
ACE: Alliance for Clean Energy
ACEEE: American Council for an Energy Efficient
  Economy
ACFM: Actual Cubic Feet Per Minute
ACL: Alternate Concentration Limit
ACL: Analytical Chemistry Laboratory
ACM: Asbestos-Containing Material
ACP: Air Carcinogen Policy
ACQUIRE: Aquatic Information Retrieval
ACQR: Air Quality Control Region
ACS: American Chemical Society
ACT: Action
ACTS: Asbestos Contractor Tracking System
ACWA: American Clean Water Association
AD ABA: Acceptable Data Base
ADB: Applications Data Base
ADI:  Acceptable Daily Intake
ADQ: Audits of Data Quality
ADP: Applications Data Base
ADR: Alternate Dispute Resolution
ADSS: Air Data Screening System
ADT: Average Daily Traffic
AEA: Atomic Energy Act
AEC: Associate Enforcement Counsels (OECM)
AEE:  Alliance for Environmental Education
AEERL: Air and  Energy  Engineering Research
  Laboratory
AEM: Acoustic Emmision Monitoring
AERE: Association of Environmental and Re-
  source Economists
AES: Auger Electron Spectometry
AFCA: Area Fuel Consumption Allocation
AFRCE: Air Force Regional Civil Engineers
AFS: AIRS Facility Subsystem
AFUG: AIRS Facility Users Group
AGC: Associate General Counsels (OGC)
AH: Allowance Holders
AHERA: Asbestos Hazard Emergency Response
  Act
AI: Artificial Intelligence
AICE: American Institute of Chemical Engineers
 AICUZ: Air Installation Compatible Use  Zones
 AID: Agency for International Development
AIG: Assistant Inspector Genera!
AIHC: American Industrial Health Council
 AIP:  Auto Ignition Point
AIRS: Aerometnc Information Retrieval System
AL: Acceptable Level
AL: Administrative Leave
AL: Annual Leave
ALA: American Lung Association
ALA:  Uelta-Aininolevuhiuc Acid
ALA-O: rX'Ita-A.ninoIexulmic Acid Dehydrates
ALAPO: Association ot Local Air Pollution Con-
  trol Officers
 20
ALARA: As Low As Reasonably Achievable
ALC: Application Limiting Constituent
ALJ: Administrative Law Judge
ALMS: TALMS without the tunable
ALR: Action Leakage Rate
AMA: American Medical Association
AMBIENS: Atmospheric Mass Balance of In-
  dustrially Emitted and Natural Sulfur (ex-
  perimental investigation by the MAP3S Com-
  munity)
AMPS: Automatic Mapping and Planning System
AMS: American Meteorological Society
AMSA: Association of Metropolitan Sewer Agen-
  cies
ANPR: Advance Notice of Proposed Rulemaking
ANSS: American Nature Study Society
AO: Administrative Officer
AO: Administrator's Office
AO: Administrative Order (on consent)
AO: Area Office
AO: Awards and Obligations
AOC: Abnormal Operating Conditions
AOD: Argon-Oxygen Decarbonization
AOML: Atlantic Oceanographic and Meteorlogi-
  cal Laboratory
AP: Accounting Point
APA: Administrative Procedures Act
APCA: Air Pollution Control Association
APCD: Air Pollution Control District
APDS: Automated  Procurement Documentation
  System
APHA: American Public Health Association
APRAC: Urban Diffusion Model for  Carbon
  Monoxide from Motor Vehicle Traffic
APT: Associated Pharmacists and Toxicologists
APTI: Air Pollution Training Institute
APWA: American Public Works Association
AQ-7: Non-reactive Pollutant Modeling
AQCCT: Air Quality Criteria and Control Tech-
  niques
AQCR: Air Quality Control Region (CAA)
AQD: Air Quality Digest
AQDHS: Air Quality Data Handling  System
  (OAR)
AQDM: Air Quality Display Model
AQMA: Air Quality Maintenance Area
AQMP: Air Quality Maintenance Plan
AQMP: Air Quality Management Plan
AQSM: Air Quality Simulation Model
AQTAD: Air  Quality Technical Assistance
  Demonstration
A&R: Air and Radiation
ARA: Assistant Regional Administrator
ARA: Associate Regional Administrator
ARAR: Applicable  or Relevant and Appropriate
  Standards, Limitations,  Criteria, and Require-
  ments
ARE: Air Resources Board
ARC: Agency Ranking  Committee:
ARCC: American Rivers Conservation Council
ARG: American Resources Group
ARIP: Accidental Release Information Program
ARM: Air Resources Management
ARO: Alternate Regulatory Option
ARRP: Acid Rain Research Program
ARRPA:  Air Resources Regional Pollution Assess-
  ment Model
ARZ: Auto-restricted Zone
AS: Area Source
ASC: Area Source  Category
ASCII: American Standard Code  for Information
  Interchange
ASDWA: Association of State Drinking Water Ad-
  ministrators
ASHAA: Asbestos  in Schools Ha/aru Abatement
  Act.
ASIWCPA: Associauon of  State and Interstate
  Water Pollution Control Administrators
ASMDHS: Airshed Model Data Handling System
ASRL: Atmospheric Sciences Research Laboratory
 ASTHO: Association of State and Territorial
  Health  Officers ASTSWMO. Association of
  State and Territorial Solid Waste Management
  Officials
AT: Advanced Treatment (water)
ATERIS: Air Toxics Exposure and Risk Informa-
  tion System (ORD)
ATS: Action Tracking System
ATS: Administrator's Tracking System
ATSDR: Agency for Toxic Substances and Disease
  Registry (HHS)
ATTF: Air Toxics Task Force
AUSA: Assistant United States Attorney
AUSM: Advanced Utility Simulation Model
A/WPR: Air/Water Pollution Report
AWRA: American Water Resources Association
AWWA: American Water Works Association
AWWARF: American Water Works  Association
  Research Foundation AX: Administrator's
  Office
B
BAA: Board of Assistance Appeals (OGC)
BAC: Biotechnology Advisory Committee
BACT: Best Available Control Technology
BADT: Best Available Demonstrated Technology
BaP: Benzo(a)Pyrene
BAP: Benefits Analysis Program
BART: Best Available Retrofit Technology
BASIS: Battelles Automated Search Information
  System
BAT: Best Available Treatment
BATEA: Best Available Technology Economically
  Achievable
BBS: Bulletin Board System
BCC: Blind Carbon Copy
BCCM: Board for Certified Consulting Meteoro-
  logists
BCT: Best Control Technology
BCT: Best Conventional Pollutant Control Tech-
  nology
BOAT: Best Demonstrated Achievable Technolo-
  gy
BDT: Best Demonstrated Technology
BEJ: Best Expert Judgment
BEP: Black Employment Program
BG: Billion Gallons
HI: Brookings Institution
BIA: Bureau  of Indian  Affairs
BID: Background Information Document
BID: Buoyancy Induced Dispersion
BIOPLUME: Model to Predict the Maximum Ex-
  tent of Existing Plumes
BLM: Bureau of Land Management'
BLOB: Biologically Liberated Organo-Beasties
BLS: Bureau  of Labor Statistics
BMP: Best Management Practice(s)
BMR: Baseline Monitoring Report (CWA)
BOD: Biochemical Oxygen Demand
BOD: Biological Oxygen Demand
BOF: Basic Oxygen Furnace
BOM: Bureau of Mines
BOP: Basic Oxygen Process
BOPF: Basic  Oxygen Process Furnace
BOYSNC: Beginning of Year Significant  Non-
  Comphers
BP: Boiling Point

BPA: Blanket Purchase Agreement
BPJ:  Best Professional Judgment
BPT: Best Practicable Technology
BPT: Best Practicable Control Technology
BPT: Best Practicable Treatmert

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 RS: Bibliographic Retrieval Service
 SO: Benzene Soluble Organics
 TU: British Thermal Unit
 TZ: Below the Treatment Zone
 U: Bargaining Unit
 UN: Blood Urea Nitrogen
 Y: Budget Year
 ': Celsius
 'A: Citizen Act
 'A: Competition Advocate
 'A: Cooperative Agreements
 'A: Corrective Action
 !AA: Clean Air Act
 !AA: Compliance Assurance Agreement
 'AAA: Clean Air Act Amendments
 ^AB: Civil Aeronautics Board
 .'AD: Computer Assisted Design
 'AER: Community Awareness and  Emergency
  Response
 'AFE: Corporate Average  Fuel Economy
 'AFO: Consent Agreement/Final Order
 'AG: Carcinogenic Assessment Group
 -AIR: Comprehensive Assessment of Informa-
 tion Rule
 SALINE: California Line Source Model
 TAMP: Continuous Air Monitoring Program
 TAN: Common Account Number
 ^AO: Corrective Action Order
 -AP: Corrective Action Plan
 -AP: Cost Allocation Procedure
 TAP: Criteria Air Pollutant
 TAR: Corrective Action Report
 ZASAC: Clean Air Scientific Advisory Committee
 IAS: Center for Automotive Safety
 IAS: Chemical Abstract Service
 ~ASLP: Conference on Alternative State and Local
  Practices
 ZATS: Corrective Action Tracking System
 ~AU: Carbon Adsorption Unit
 IAU: Command Arithmetic Unit
 2B: Continuous Bubbler
 IBA: Chesapeake Bay Agreement
 ZBA: Cost Benefit Analysis
CBD: Central  Business District
CBD: Commerce Business Daily
CBI: Compliance  Biomonitoring  Inspection
  (CWA)
CBI: Confidental Business Information
CBO: Congressional Budget Office
CBOD: Carbonaceous Biochemical Oxygen De-
  mand
CBP: Chesapeake Bay Program
CBP: County  Business Patterns
CC:  Carbon Copy
CCA: Competition in Contracting Act
CCAA: Canadian Clean Air Act
CCAP: Center for Clean Air Policy
CCEA: Conventional Combustion Environmental
  Assessment
CCHW: Citizens Clearinghouse  for  f-^ardous
 Wastes
CCID: Confidential  Chemicals Identification
 System
CCMS/NATO  : Committee  on Challenges of a
 Modern Socu'ty'Noith Atlantic I'reatv Organ-
 ization
CO': Composite Correction  Plan (CVVAl
CC'RIS: Chemical  C oi!ectumloj;v
O;  ChmaiokxK'd! ?>.,' .
C ill": Co'1-.olidaT..M ()," •• l'..^'
CDD: Chlorinated dibenzo-p-dioxin
CDF: Chlorinated dibenzoturan
CDHS: Comprehensive Data Handling System
 (OAR)
CDI: Case Development Inspection
CDM: Climatological Dispersion Model
COM: Comprehensive Data Management
CDMQC: Climatological Dispersion Model with
  Calibration and Source Contribution.
CDNS: Climatological Data National Summary
CDP: Census Designated Places
CDS: Compliance Data System
CE: Categorical Exclusion
CE: Cost Effectiveness
CEA: Cooperative Enforcement Agreement
CEA: Cost and Economic Assessment (OECM)
CEA: Council of Economic Advisors
CEAT: Contractor Evidence Audit Team
CEARC: Canadian Environmental Assessment
  Research Council
CEB: Chemical Element Balance
CEC: Commission of European Communities
CECATS: CSB Existing Chemicals Assessment
 Tracking System (OPTS)
CEE: Center for Environmental Education
CEEM: Center for  Energy and Environmental
  Management
CEI: Compliance Evaluation Inspection (CWA)
CELRF: Canadian Environmental  Law Research
  Foundation
CEM: Continuous Emission Monitoring (CAA)
CEMS: Continuous Emission Monitoring System
CEO: Chief Executive Officer
CEPP: Chemical Emergency Preparedness Plan
CEQ: Council on Environmental Quality
CERCLA: Comprehensive Environmental Re-
  sponse, Compensation, and Liability Act of 1980
CERCLIS: Comprehensive Environmental Re-
  sponse, Compensation, and Liability Informa-
  tion System (OSWER)
CERI: Center for Environmental Research In-
  formation
CERT: Certificate of Eligibility
CEU: Continuing Education Units
CF: Conservation Foundation
CFA: Consumer Federation of American
CFC: Chlorofluorocarbons
CFM: Chlorofluoromethanes
CFM: Cubic Feet Per Minute (ft. 3/min. preferred
  except with ACFM or SCFM)
CFR: Code of Federal Regulations
CFS: Cubic feet per second
CHABA: Committee on Hearing  and Bio-
  Acoustics
CHAMP: Community Health Air Monitoring Pro-
  gram
CHEMTREC: Chemical Transportation Emergen-
  cy Center
CHESS: Community Health and Environmental
  Surveillance System
CHIP: Chemical Hazard Information Profile
CI: Compression Ignition
CI: Confidence Interval
CIAQ: Council on Indoor Air Quality
CIBL: Convective Internal  Boundary Layer
CICA: Competition in Contracting Act
CICIS: Chemicals in Commerce Information Sys-
  tem
CIDRS: Cascade Impactor Data Reduction System
CIM!: Committee on Integrity and Management
  Improvement
CiS: Chemical Information  bvstcm
CIS: Contiact-. Information System
CJF: v ntKal loo LViivjni
OP: Ch'i'i Indicia! OKcer
CLEVER: Clinical Laboratory for Evaluation and
 Validation of Epidemiologic Research
CLF: Conservation Law Foundation
CLIPS: Chemical List Index and  Processing
 System
CLP: Contract Laboratory Program
CM: Corrective Measure
CMA: Chemical Manufacturers Association
CMB: Chemical Mass Balance
CME: Comprehensive (ground water) Monitoring
  Evaluation
CMEL: Comprehensive (ground water) Monitor-
 ing Evaluation Log
CMEP: Critical Mass Energy Project
COCO: Contractor-Owned/Contractor-Operated
COD: Chemical Oxygen demand
COE: U.S. Army Corps of Engineers
COH: Coefficient of Haze
CONG: Congressional Committee
CPF: Carcinogenic Potency Factor
CPI: Consumer Price Index
CPO: Certified Project Officer
CPR: Center for Public Resources
CPSC:  Consumer Product  Safety Commission
CQA: Construction Quality Assurance
CR: Community Relations
CROP: Consolidated Rules of Practice
CRR: Center for Renewable Resources
CRS: Congressional Research Service
CRSTER: Single Source Dispersion Model
CSI: Clean Sites, Inc.
CSI: Compliance Sampling Inspection (CWA)
CSIN: Chemical Substances Information Network
CSMA: Chemical Specialties  Manufacturers
 Association
CSO: Combined Sewer Overflow
CSPA: Council of State Planning Agencies
CSPI: Center for Science in the Public Interest
CSRL:  Center for the  Study of Responsive Law
CTARC: Chemical Testing and  Assessment Re-
  search Commission
CW: Congress Watch
CWA: Clean Water Act (aka FWPCA)
CWAP: Clean Water Action Project
CWTC: Chemical Waste Transportation Council
DA: Deputy Administrator
DAR: Defense Acquisition Regulations
dB: Decibel
DCA: Document Control Assistant
DCO: Delayed Compliance Order (CAA)
DCO: Document Control Officer
DDT: D(Ichloro)D(Iphebyl)T(Richloroethane)
DES: Diethylstilbesterol
DI: Diagnostic Inspection (CWA)
DMR: Discharge Monitoring Report
DNA: Deoxynbonucleic acid
DO: Dissolved Oxygen
DOC: Department of Commerce
DOD: Department of Defense
DOE: Department of Energy
DOI: Department of Interior
DOJ: Department of justice
DOL: Department of Labor
DOS: Department of State
DOT: Department of Transportation
DOW: Defenders of Wildlife
DPA: Deepvvater Ports Act
DQO: Data OuahtN Ob]C".!m>
DRA: Depuh Regional  Administrator
DRC: Depurv licgionj; Cmir-.rl
       He-- -i .1- i\oi.'
-------
DSCF: Dry Standard Cubic Feet
DSCM: Dry Standard Cubic Meter
DSS: Decision Support System
DSS: Domestic Sewage Study
DT: Detention Time
DU: Decision  Unit
DU: Ducks Unlimited
DUC: Decision Unit Coordinator:
DWS: Drinking Water Standard
EA: Endangerment Assessment
EA: Enforcement Agreement
EA: Environmental Action
EA: Environmental Assessment (NEPA)
EA: Environmental Audit
EAF: Electric Arc Furnaces
BAG: Exposure Assessment Group (ORD)
EAP: Environmental Action Plan
EAR: Environmental Auditing Roundtable
EB: Emissions Balancing
EBCDIC: Extended Binary Coded Decimal Inter-
  change Code
EC: European Community (Common Market)
EC: Environment Canada
EC: Effective Concentration
ECA: Economic Community for Africa
ECAP: Employee Counseling and Assistance Pro-
  gram
ECD: Electron Capture Detector
ECE: Economic Commission for Europe
ECHH: Electro-Catalytic Hyper-Heaters
ECL: Environmental Chemical Laboratory
ECL: Executive Control Language
ECLA: Economic Commission for Latin America
ECRA: Economic Cleaup Responsibility Act
ED: Department of Education
ED: Effective Dose
EDA: Economic Development Administration
EDA: Emergency Declaration  Area
EDB: Ethylene Dibromide
EDC: Ethylene Dichloride:
EDD: Enforcement Decision Document
EDF: Environmental Defense  Fund
EDP: Electronic Data Processing
EDRS: Enforcement Document Retrieval  System
EDS: Electronic Data System
EDS: Energy Data System
EDT: Edit Data Transmission
EDTA: Ethylene Diamine Triacetic Acid
EDZ: Emission Density Zoning
EEA: Energy and Environmental Analysis
EEC: European Economic Commission
EEG: Electroencephalogram
EEI: Edison Electric Institute
EENET: Emergency Education Network (FEMA)
EEOC: Equal Employment Opportunity Commis-
  sion
HER: Excess Emission Report
EERL: Eastern Environmental Radiation  Labora-
  tory:
EESI: Environment and Energy Study  Institute
EESL: Environmental Ecological and Support Lab-
  oratory
EERU: Environmental Emergency Response Unit
EETFC: Environmental Effects, Transport and
  Fate Committee
EF: Emission Factor
EFO: Equivalent Field Office
TFTC: European  Fluorocarbon Technical Com-
  -.•ttee
                        ,' tion
EIA: Economic Impact Assessment
EIA: Environmental Impact Assessment
EIL: Environmental Impairment Liability
EIR: Endangerment Information Report
EIR: Environmental Impact Report
EIS: Environmental Inventory System
BIS: Environmental Impact Statement (NEPA)
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
EM: Electron Microscope
E-MAIL: Electronic Mail
EMAS: Enforcement Management and Account-
  ability System (OECM)
EMI: Emergency Management Institute
EMR: Environmental  Management Report
EMS: Enforcement Management System
EMSL: Environmental Monitoring Support Lab-
  oratory
EMSL: Environmental Monitoring Systems Lab-
  oratory
EMTS: Environmental Monitoring Testing Site
EMTS: Exposure Monitoring Test  Site
EO: Ethylene Oxide
EO: Executive Officer
EO: Executive Order
EOB: Executive Office Building
EOC: Emergency Operating Center
EOD: Entrance on Duty
EOE: Equal Opportunity Employer
EOJ: End of Job
EOF: Emergency Operations Plan
EOT: Emergency Operations Team
EOY: End of Year
EP: Earth Protectors
EP: Environmental Profile
EP: Extraction Procedure
EPA: U.S  Environmental Protection Agency
EPAA: Environmental Programs Assistance Act:
EPAAR: EPA Acquisition Regulations
EPACASR: EPA Chemical Activities Status Report
EPAYS: EPA Payroll System
EPCA: Energy Policy  and Conservation Act
EPD: Emergency Planning District
EPI: Environmental Policy Institute
EPIC: Environmental Photographic Interpretation
  Center
EPNL: Effective Perceived Noise Level
EPO: Estuarine Programs Office (NOAA)
EPRI: Electric Power Research Institute
EPTC: Extraction Procedure Toxicity Characteris-
  tic
ER: Electrical Resistivity
ERA: Economic Regulatory Agency
ERAMS: Environmental  Radiation  Ambient
  Monitoring System (OAR)
ERC: Emergency Response Commission
ERC: Emissions Reduction Credit
ERC: Environmental Research Center
ERCS: Emergency Response Cleanup Services
ERDA: Energy  Research and Development Ad-
  ministration
ERD&DAA: Environmental Research, Develop-
  ment and Demonstration  Authorization Act
ERL: Environmental Research Laboratory
ERNS: Emergency Response Notification System
ERP: Enforcement Response Policy
ERT: F.mergenc1, Response Team
'           '   '
ESCA: Electron Spectroscopy for Chemical Anal-
  ysis
ESCAP: Economic and Social Commission for Asia
  and the Pacific
ESECA: Energy Supply and  Environmental
  Coordination Act
ESH: Environmental Safety and Health
ESP: Electrostatic Precipitators
ET: Emissions Trading
ETP: Emissions Trading Policy
ETS: Environmental Tobacco Smoke
EWCC: Environmental Workforce Coordinating
  Committee
EX: Executive Level Appointment
ExEx: Expected Exceedance
EUP: Environmental Use Permit
F: Fahrenheit (Degrees)
FAA: Federal Aviation Administration
FACA: Federal Advisory Committee Act
FACM: Friable Asbestos-Containing Material
FAM: Friable Asbestos Material
FAME: Framework for Achieving Managerial Ex-
  cellence
FAN: Fixed Account Number
FAO: Food and Agriculture Organization
FAR: Federal Acquisition Regulations
FASB: Financial Accounting Standards Board
FATES: FIFRA and TSCA Enforcement System
FBC: Fluidized bed combustion
FCC: Federal Communications Commission
FCC: Fluid Catalytic Convert
f/cc: Fibers per cubic centimeters (of air)
FCCU: Fluid Catalytic Cracking Unit
FCO: Federal Coordinating Officer (in  disaster
  areas)
FCO: Forms Control Officer
FDA: Food and Drug Administration
FDF: Fundamentally Different Factors
FDIC: Federal Deposit Insurance Corporation
FDL: Final Determination Letter
FDO: Fee Determination Official
FE: Fugitive Emissions
FEA: Federal Energy Administration
FEC: Federal Executive Council
FEDS: Federal Energy Data System
FEFx: Forced Expiratory Flow
FEHB: Federal Employees Health Benefits
FEI: Federal Executive Institute
FEIS: Fugitive Emissions Information Systemyu
PEL: Frank Effect Level
FEMA: Federal Emergency Management Agency
FEMA-REP-1: Response Plans and Preparedness
  in Support of Nuclear Power Plants
FEMA-REP-2: Guidance for Developing State and
   Local Radiological Emergency Response Plans
   and Preparedness for Transportation Actions
FERC: Federal Energy Regulatory Commission
FERSA: Federal Employee Retirement System Act
FES: Factor Evaluation System
FEV: Forced Expiratory Volume
FEV1:  Forced Expiratory Volume - one second
FEVI: Front End Volatility Index
FEW: Federally Employed Women
FF: Federal Facilities
FFF: Firm Financial Facility
FFAR: Fuel and Fuel Additive Registration
FFDCA: Federal Food, Drug, and Cosmetic Act
FFFSG: Fossil Fuel Fired  Steam  Generator
'TIS: Federal FdvilHis- Information  S,«k"n
ifP: Firm i'iv. J  ! n,\

-------
FHA: Federal Housing Administration
FHLBB: Federal Home Loan Bank Board
FHWA: Federal Highway Administration
FIA: Federal Insurance Administration
FIC: Federal Information Center
FICA: Federal Insurance Contributions  Act
FID: Flame lonization Detector
FIFO: First In/First Out
FIFRA: Federal Insecticide, Fungicide, and Roden-
  ticide Act
FIM: Friable Insulation Material
FINDS: Facility Index System (OIRM)
FIP: Federal Implementation Plan
FIP: Federal Information Plan
FIP: Final Implementation Plan
FIPS: Federal Information Procedures System
FIT: Field Investigation Team
FLETC: Federal Law Enforcement Training Center
FLM: Federal Land Manager
FLPMA: Federal Land Policy and Management
 Act
FLSA: Fair Labor Standards Act
FLP: Flash Point
FM: Friable Material
F/M: Food to Microorganism Ratio
FMC: Federal Maritime Commission
FMFIA: Federal Managers Financial Integrity Act
FML: Flexible Membrane Liner
FMO: Financial Management Officer
FMP: Facility Management Plan
FMP: 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 Dipol An-
  tenna
FONSI: Finding of No Significant Impact (NEPA)
FORAST: Forest Response  to Anthropogenic
 Stress
FORTRAN: Formula Translation
FP: Fine Particulate
FPA: Federal Pesticide Act
FPC: Federal Power Commission
FPD: Flame Photometric Detector
FPEIS: Fine Particulate Emissions Information
 System
FPM: Federal Personnel Manual
FPR: Federal Procurement Regulation
FPRS: Federal  Program Resources Statement
FPRS: Formal Planning and Supporting System
FR: Federal Register
FR: Final Rulemaking
FRA: Federal Register Act
FRB: Federal Reserve Board
FRC: Federal Records Center
FRDS: Federal Reporting Data System
FREDS: Flexible Regional Emissions Data System
FRES: Forest Range Environmental Study
FRM: Federal Reference Methods
FRN: Final Rulemaking Notice
FRS: Formal Reporting System
FRTIB: Federal Retirement  Thrift Investment
 Board
FS: Feasibility  Study
FS: Forest Service
FSA: Food Security Act
FSS: Facility Status Sheet
FSS: Federal Supply Schedule
FT: Full Time
FTC: Federal Trade Commission
FTE: Full Time Equivalent
FTP: Federal Test Procedure (for motor vehicles)
FTS: Federal Telecommunications System
FTS: File Transfer Service
FTT: Full-Time Temporary
FUA: Fuel Use Act
 FURS: Federal Underground Injection Control
  Reporting System
 FVC: Forced Vital Capacity
 FVMP: Federal Visibility Monitoring Program
 FWCA: Fish and Wildlife Coordination Act
 FWP: Federal Women's Program
 FWPCA: Federal Water Pollution Control Act (aka
  Clean Water Act, or CWA)
 FWPCA: Federal Water Pollution  Control Ad-
  ministration
 FWS: Fish and Wildlife Service
 FY: Fiscal Year
 FYI: For Your Information
GAAP: Generally Accepted Accounting Principles
GAC: Ground-Water Activated Carbon
GACT: Granular Activated Carbon Treatment
GAO: General Accounting Office
GBL: Government Bill of Lading
GC: Gas Chromatograph
GC: General Counsel
GC/MS: Gas Chromatograph/Mass Spectograph
GCWR: Gross Combination Weight Rating
GEA: Glossary of EPA Acronyms
GEI: Geographic Enforcement Initiative
GEMS: Global Environmental Monitoring System
GEMS: Graphical Exposure Modeling System
 (OTS)
GEP: Good Engineering Practice
GF: General Files
GFF: Glass Fiber Filter
GFP: Government-Furnished Property
GI: Gastrointestinal
GICS: Grant Information and Control System
GIS: Geographic Information Systems
GIS: 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
GMT: Greenwich Mean Time
GNP: Gross National Product
GOCM: Goals,  Objectives, Commitments, and
 Measures
GOCO: Goverment-Owned/Contractor-Operated
GOGO:Goverment-Owned/Government-
 Operated
GOP: General Operating Procedures
GOPO: Goverment-Owned/Privately-Operated
GPAD: Gallons per acre per day
GPG: Grams per Gallon
GPO: Government Printing Office
GPR: Ground-Penetrating Radar
GPS: Ground-Water Protection Strategy
GRGL: Ground-Water Residue  Guidance Level
GS: General Schedule
GSA: General Services Administration
GTN: Global Trend Network
GTR: Government Transportation Request
GVP: Gasoline Vapor Pressure
GVW: Gross Vehicle Weight
GVWR: Gross Vehicle Weight Rating
GW: Ground Water
GWM: Ground-Water Monitoring
GWPS: Ground-Water Protection Standard
GWPS: Ground-Water Protection Strategy
H
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 Matenal
HAZOP: Hazard and Operability Study
HB: Health Benefits
HBEP: Hispanic and Black Employment Programs
HC: Hazardous Constituents
HCCPD: Hexachlorocyclopentadiene
HCP: Hypothermal Coal  Process
HDD: Heavy-Duty Diesel
HDE: Heavy-Duty Engine
HDG: Heavy-Duty Gasoline-Powered Vehicle
HOPE: High Density Polyethelene
HDT: Heavy-Duty Truck
HDV: Heavy-Duty Vehicle
HEAL: Human Exposure Assessment Location
HECC: House Energy and Commerce Committee
HEI: Health Effects Institute
HEM: Human Exposure Modeling
HEP: Hispanic Employment Program
HEPA: High-Efficiency Particulate Air
HERL: Health Effects Research Laboratory
HERS: Hyperion Energy  Recovery System
HEX-BCH: Hexachloronorbornadiene
HHE: Human Health and the Environment
HHS: Department of Health and Human Services-
  Formerly HEW
HHV: Higher Heating Value
HI: Hazard Index
HI-VOL: High-Volume Sampler
HIWAY: A Line Source Model for Gaseous Pollut-
  ants
HLRW: High-Level Radioactive Waste
HMIS: Hazardous Matenals Information System
HMS: Highway Mobile Source
HMTA: Hazardous Materials Transportation Act
HMTR: Hazardous Materials Transportation
  Regulations
HO: Headquarters Offices
HOC: Halogenated Organic Carbons
HON: Hazardous Organic NESHAP
HOV: High-Occupancy Vehicle
HP: Horse Power
HPLC: High Performance Liquid Chromatogra-
  phy
HPV: High Priority Violater
HQ: Headquarters
HQCDO: Headquarters Case Development Offi-
  cer
HRC: Human Resources  Council
HRS: Hazardous Ranking System
HRUP: High Risk Urban  Problem
HSDB: Hazardous Substance Data Base
HSL: Hazardous Substance List
HSWA: Hazardous and Solid Waste Amend-
  ments:
HT: Hypothermally Treated
HTP: High Temperature and Pressure
HUD: Department  of Housing and Urban De-
  velopment
HVAC: Heating, Ventilation, and Air Condition-
  ing (System)
HVIO: High Volume Industrial Organics
HW: Hazardous Waste
HWDMS: Hazardous Waste Data Management
  System (OSWER)
HWERL: Hazardous Waste Engineering Research
  Laboratory
HWGTF: Hazardous Waste Ground Water Task
  Force
                                                                                                                                   23

-------
HWGTF: Hazardous Waste Ground Water Test
 Facility
HWLT: Hazardous Waste Land Treatment
HWM: Hazardous Waste Managment
HWRTF: Hazardous Waste Restrictions Task
 Force
HWTC: Hazardous Waste Treatment Council
I

IA: Interagency Agreeement
IAAC: Interagency Assessment Advisory Com-
 mittee
IAEA: International Atomic Energy Agency
IAG: Interagency Agreement
IAP: Incentive Awards Program
IAP: Indoor Air Pollution
IARC: International Agency for Research on
 Cancer
IARDB: Interim Air Toxics Data Base
IBA: Industrial Biotechnology Association
IBRD: International Bank for Reconstruction and
  Development
ICAIR: Interdisciplinary Planning and Informa-
 tion Research
ICAP: Inductively Coupled Argon Plasma
ICBN: International Commission on the Biological
  Effects of Noise
ICC: Interstate Commerce Commission
ICE: Industrial Combustion Emissions Model
ICE: Internal  Combustion Engine
ICP: Inductively Coupled Plasma
ICR: Information Collection Request
ICRE:  Ignitability, Corrosivity, Reactivity, Extrac-
  tion (Characteristics)
ICRP: International Commission on Radiological
  Protection
ICS: Institute for Chemical Studies:
ICS: Intermittent Control Strategies
ICS: Intermittent Control System (CAA)
ICWM: Institute for Chemical Waste Management
ID: Inside Diameter
IDLH: Immediately Dangerous to Life  and
 Health:
IEB: International Environment Bureau
IEMP: Integrated Environmental Management
 Project
IES: Institute  for Environmental Studies
IFB: Invitation for Bid
IFCAM: Industrial Fuel  Choice Analysis Model
IFIS : Industry File Information System
IFPP: Industrial Fugitive Process Particulate
IG: Inspector  General
IGCI: Industrial Gas Cleaning Institute
IIS: Inflationary Impact Statement
IJC: International Joint  Commission  (on Great
 Lakes)
I/M: Inspection/Maintenance
IMM: Intersection Midblock Model
IMPACT: Integrated Model of Plumes and Atmos-
  phere in Complex Terrain
IMPROVE: Interagency Monitoring of Protected
 Visual Environment
INPUFF: A Gaussian Puff Dispersion Model
INT: Intermittent
IO: Immediate Office
IOAA: Immediate Office of the Assistant Adminis-
  trator
IOAU: Input/Output Arithmetic Unit
IOB: Iron Ore Beneficiation
IOU: Input/Output Unit
IP: Inhalable Particles
IPA: Intergovernmental Personnel Act
IPA: Intergovernmental Personnel Agreement
IPM: Inhalable Particulate Matter
IPM: Integrated Pest Management
IPP: Implementation Planning Program
 IPP: Integrated Plotting Package
 IPP: Intermedia Priority Pollutant (document)
 IPCS: International Program on Chemical Safety
 IR: Infrared
 IRG: Interagency Review Group
 IRIS: Instructional Resources Information System
 IRIS: Integrated Risk Information System
 IRM: Intermediate Remedial Measures (CERCLA)
 IRMC: Inter-Regulatory Risk Management Coun-
  cil
 IRP: Installation Restoration Program
 IRPTC: International Register of Potentially Toxic
  Chemicals
 IRR: Institute of Resource Recovery
 IRS: Internal Revenue Service
 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 (RCRA)
 ISE: Ion-specific electrode
 ISMAP: Indirect Source Model for Air Pollution
 ISS: Interim Status Standards
 ITC: Interagency Testing Committee
 ITC: International Trade Commission
ITDP: Individual Training and Development Plan
 ITP: Individual  Training Plan
 IWC: In-Stream Waste Concentration (CWA)
 IWS: Ionizing Wet Scrubber
JAPCA: Journal of Air Pollution Control Associa-
   tion
JCL: Job Control Language
JEC: Joint Economic Committee
JLC: Justification for Limited Competition
JNCP: Justification for Non-Competitive Procure-
  ment
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
K
KW: Kilowatt
KWH: Kilowatt Hour
LAA: Lead Agency Attorney
LAER: Lowest Achievable Emission Rate
LAI: Laboratory Audit Inspection
LAMP: Lake Acidification Mitigation Project
  (EPRI)
LC: Lethal Concentration
LC: Liquid Chromatography
LCD: Local Climatological Data
LCL: Lower  Control Limit
LCM: Life Cycle Management
LCRS: Leachate Collection and Removal System
LD: Land Disposal
LD: Light Duty
LD50: Low Dose Where Fifty Percent of Animals
  Die
LDC: London Dumping Convention
LDCRS: Leachate Detection, Collection, and Re-
  moval System
LDD: Light-Duty Diesel
LDIP: Laboratory Data Integrity Program
LDR: Land Disposal Restrictions
LDRTF: Land Disposal Restrictions Task Force
LDS: Leak Detection System
LOT: Light-Duty Truck
LDV: Light-Duty Vehicle
LEL: Lower Explosive  Limit
LEP: Laboratory Evaluation Program
LEPC: Local Emergency Planning Committee
LERC: Local Emergency Response Committee
LFL: Lower Flammability Limit
LIDAR: Light Detection and Ranging
LIFO: Last In/First Out
LIMB: Limestone-Injection, Multi-Stage Burner
LLRW: Low Level Radioactive Waste
LMFBR: Liquid Metal  Fast Breeder Reactor
LMR: Labor Management Relations
LNEP: Low Noise Emission Product
LNG: Liquified Natural Gas
LOAFL: Lowest Observed  Adverse Effect Level
LOC: Library of Congress
LOE: Level of Effort
LOEL: Lowest Observed Effect Level
LOIS: Loss of Interim  Status (SDWA)
LONGZ: Long-Term Terrain Model
LOQ: Level of Quantitation
LP: Legislative Proposal
LPG: Liquified Petroleum Gas
LSI: Legal Support Inspection (CWA)
LSL: Lump Sum  Leave
LST: Low-Solvent Technology
LTA: Lead Trial Attorney
LTD: Land Treatment  Demonstration
LTO: Landing-Takeoff Cycle
LTOP: Lease to Purchase
LTR: Lead Technical Representative
LTU: Land Treatment  Unit
LUST: Leaking underground Storage Tank(s) (cur-
  rent usage omits the "L")
LWCF: Land and Water Conservation Fund:
LWOP: Lease with Option to Purchase:
LWOP: Leave Without Pay
M

MAB: Man and Biosphere Program
MADCAP: Model of Advection, Diffusion, and
 Chemistry for Air Pollution
MAER: Maximum Allowable Emission Rate
MAG: Management Advisory Group
MAP3S: Multistate Atmospheric Power Produc-
 tion Pollution Study
MAPPER: Maintaining, Preparing, and Producing
  Executive Reports
MAPSIM: Mesoscale  Air  Pollution Simulation
 Model
MARC: Mining and Reclamation Council
MATC: Maximum Allowable Toxicant Concentra-
  tion
MBDA: Minority Business Development Agency
MBE: Minority Business Enterprises
MCA: Manufacturing Chemists Aassociation
MCEF: Mixed  Cellulose Ester Filter
MCL: Maximum Contaminant Level
MCLG: Maximum Contaminant Level Goal
MCP: Municipal Compliance Plan (CWA)
MD: Mail Drop
MDA: Methylenedianilline
MDL: Method Detection Limit
MEFS: Midterm  Energy Forecasting System
MEI: Maximum Exposed Individual:
MEK: Methyl Ethyl Ketone
MEM: Modal Emission Model
MENS:  Mission Element Needs Statement
24

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MEP: Multiple Extraction Procedure
MERL: Municipal Environmental Reseaich  Lah-
  oratory
MESOPAC: Mesoscale Meteorological KepuKo-;-
  ser Program
MESOPLUME: Mesoscale  'Bent Plume" Modtl
MESOPUFF: Mesoscale Putf Model
MESS: Model Evaluation Support System
MFBI: Major Fuel Burning Installation
MFC: Metal Finishing Category
MGD: Million Gallons Per Dav
MH: Man-Houis
MHD: Magnetohydrodynamics.
MIBK: Methyl Isobutyl Ketone
MIC: Methyl Isocaynate
MICE: Management  Information Capability for
  Enforcement
M1CROMORT: A One-in-a-Million Chance  ot
  Death from an Environmental Hazard
MIPS: Millions of Instructions Per Second
MIS: Management Information System
MIS: Mineral Industry Surveys
MITS: Management Information Tracking System
ML: Meteorology  Laboratory:
ML: Military Leave
MLAP: Migrant Legal Action Program
MLSS: Mixed Liquor Suspended Solids
MLVSS: Mixed Liquor Volatile Suspended Solids
MMS: Minerals Management Service (DO!)
MMT: Million Metric Ions
MOA; Memorandum of Agreement
MOBILE:  Mobile Source Emission Model
MOD: Miscellaneous Obligation Document
MOD: Modification
MOI: Memorandum of Intent
MOS: Margin of Safetv
MOU: Memorandum of Understanding
MP: Melting Point
MPO: Metropolitan Planning Organization
MPP: Merit  Promotion Plan
MPRSA: Marine Protection, Research and Sanc-
  tuaries Act
MPTDS: MPTER Model with Deposition and Set-
  tling of Pollutants
MPTER: Multiple Point Source Model ^.nh  Ter
  rain
MRA: Minimum Retirement Age
MRP: Multi-Roller Press  (in sludge drying unit)
MS: Mail Stop
MS: Mass Spectrometry
MSA: Management System Audits
MSA: Metropolitan Statistical Areas
MSAM: Multi-Keyed  Indexed Sequential File Ac-
  cess Method.
MSDS. Material Safetv Data Sheet
MSEE: Major Source Enforcement Effort
MSHA: Mine Safety and Health Administration
  (DOL)
MSIS: Model State Information System
MSL: Mean  Sea Level
MSPB: Merit System Protection Board
MTB: Materials Transportation Bureau
MTBE: Methyl Tertiary Butyl Ether
MTD: Maximum Tolerated Dose
MTDDIS: Mesoscale Transport Diffusion  and
 Deposition Model for Industrial Sources
MTG: Media Task Group
MTS: Management Tracking System (OW)
MTSL: Monitoring and Technical Support Labora-
  tory
MTU: Mobile Treatment Unit
MVA: Multivariate Analysis
MVAPCA: Motor Vehicle Air Pollution Control
  Act
MVEL: Motor Vehicle Emissions Laboratory
MVI/M: Motor Vehicle Inspection/Maintenance
MVICSA: Motor Vehicle Information and Cost
  Savings Act.
 MVRS: Marine Vapor Recovery System
 MVTS: Motor Vehicle Tampering Survey
 MW: Megawatt
 MW: Molecular Weight
 MWC: Municipal Waste Combusloi
 MWG: Model Work' Group
 MWL: Municipal Waste Leachate
 MYDP: Multi-Year Development Plans
 N

 NA: National Archives
 NA: Nonattamment
 N/A: Not Applicable
 N/A: Not Available
 NAA: Nonattainment Areas
 NAAQS: National Ambient Air Quality Standards
   Program (CAA)
 NAAS: National Air Audit System (OAR)
 NACA: National Agricultural Chemicals Associa-
   tion
 NADB: National Atmospheric Data Bank
 NADP: National Atmospheric Deposition Pro-
  gram
 NAIS: Neutral  Administrative Inspection
  System.
 NALD: Nonattamment Areas  Lacking  Demon-
  strations
 NAMA: National Air Monitoring Audits
 NAMS: National Air Monitoring System
 NANCO: National Association  of Noise Control
  Officials
 NAPAP: National Acid Precipitation Assessment
  Program
 NAPBN: National Air Pollution Background Net-
  work
 NAPBTAC: National Air Pollution Control Tech-
  nical Advisory Committee
 NAR: National Asbestos Registry
 NARA: National Air Resources Act
 NARA: National Archives and Records Adminis-
  tration
 N'ARS: National Asbestos-Contractor Registry
  System
 NAS: National Academy ot Sciences
 NAS: National Audubon Society
 NASA: National Aeionautics and Space Adminis-
  tration
 N/
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NMR: Nuclear Magnetic Resonance
NNC: Notice ot Noncompliance
NNPSPP: National Non-Point  Source Pollution
  Program
NOA: New Obligation Authority
NOAA: National Oceanic and Atmospheric Ad-
  ministration (DOC)
NOAEL: No Observed Adverse Effect Level
NOC: Notice ot Commencement
NOD: Notice of Deficiency (RCRA)
NOEL: No Observed Effects Level
NOHSCP: National Oil and Hazardous Sub-
  stances Contingency Plan
NON: Notice of Noncompliance (TSCA)
NOPES: Non-Occupational Pesticide Exposure
  Study
NORA: National Oil Recyclers Asssociation
NOS: National Ocean Survey (NOAA)
NOV: Notice of Violation
NOV/C/D: Notice  of  Violation/Compliance/
  Demand
NPAA: Noise Pollution  and Abatement Act
NPCA: Nationa! Parks and Conservation Associa-
  tion
NPDES: National Pollutant Discharge Elimination
  System (CWA)
NPIRES: National Pesticide Information Retrieval
  System
NPL: National Priority List (CERCLA)
NPM: National Program Manager
NPN: National Particulate Network
NPRM: Notice of Proposed Rulemaking
NFS: National Park Service
NFS: National Permit Strategy
NFS: National Pesticide Survey (OW)
NFS: Non-Point Source
NPUG: National Prime  User Group
NRA: National Recreation Area
NRC: National Research Council
NRC: National Response Center
NRC: Non-Reusable Containers
NRC: Nuclear Regulatory Commission
NRCA: National Resource Council of America
NRDC: Natural Resources Defense Council
NRT: National Response Team
NRWA: National Rural  Water Association:
NSC: National Security  Council:
NSDWR: National Secondary  Drinking  Water
  Regulations
NSF: National Sanitation Foundation
NSF: National Science Foundation
NSO: Nonferrous Smelter Orders (CAA)
NSPS: New Source Performance Standards (CAA)
NSR: New Source (Pre-construction) Review
NSTL: National Space Technology Laboratory
NSWMA: National Solid Waste Management
  Association
NSWS: National Surface Water Survey
NTA: Negotiated Testing Agreement
NTE: Not to Exceed
NTIS: National Technical Information Service
NTN: National Trends Network
NTP: National Toxicology Program
NTSP: National Transportation  Safety Board
NURF: NAPA Utility Reference File
NVPP: National Vehicle Population Poll
NWA: National Water Alliance
NWF: National Wildlife Federation
NWPA: Nuclear Waste  Policy Act
NWRC: National Weather Records Center
NWS: National Weather Service (NOAA)
 Ox: Total Oxidants
 OASDI: Old Age and Survivor Insurance
 OC: Object Class
 OCD: Offshore and Coastal Dispersion Model
 OCI: Organizational Conflicts of Interest
 OCR: Optical Character Reader
 OCS: Outer Continental Shelf
 OCSLA: Outer Continental Shelf Lands Act
 OD: Organizational Development
 OD: Outside Diameter
 OF: Optional Form
 O&G: Oil and Gas
 O&M: Operations and Maintenance
 OMB: Office of Management and Budget
 OP: Operating Plan
 OPAC: Overall Performance Appraisal Certifica-
  tion
 OFF: Official Personnel Folder
 ORM: Other Regulated Material
 ORNL: Oak Ridge National Laboratory
 ORP: Oxidation-Reduction Potential
 ORV: Off-road Vehicle
 OSC: On-Scene Coordinator
 OSHA: Occupational Safety and Health Act
 OSHA: Occupational Safety and Health Adminis-
  tration (DDL)
 OSM: Office of Surface Mining  (DOI)
 OSTP: Office of Science and  Technology Policy
  (White House)
 OS/VS: Operating System/Virtual Storage
 OT: Overtime
 OTA:  Office of Technology Assessment (US Con-
  gress)
 OY: Operating Year
 OYG: Operating Year Guidance
 OZIPP: Ozone Isopleth Plotting Package
 OZIPPM: Modified Ozone Isopleth Plotting Pack-
  age
PA: Policy Analyst
PA: Preliminary Assessment
P&A: Precision and Accuracy
PAA: Priority Abatement Areas.
PADRE: Particle Analysis  and Data Reduction
 Program
PAGM: Permit Applications Guidance Manual
PAH: i tJ  jychc Aromatic Hydrocarbon
PAHO: Pan Americn Health Organization
PAI: Performance Audit Inspection (CWA)
PAIR: Preliminary Assessment Information Rule
PAL: Point, Area, and  Line Source Air Quality
 Mode
PALDS: PAL Model with Deposition and Settling
  of Pollutants PAN: Peroxyacetyl Nitrate
PAPR: Powered Air Purifying Respirator
PARS: Precision and Accuracy Reporting System
PASS: Procurement Automated Source System
PAT: Permit Assistance Team (RCRA)
PBB: Polybromated Biphenyls
PBL: Planetary Boundary Layer
PBLSQ: The Lead Line  Source Model
PC: Personal Computer
PC: Planned Commitment
PC: Position Classification
PC: Pulverized Coal
PCA: Principle Component Analysis
PCB: Polychlorinated Biphenyls
PC&B: Personnel Compensation and Benefits
PCDD: Polychlorinated Dibenzodioxin
PCDF: Polychlonnated  Dibendzofuran
PCE: Pollution Control  Equipment
PCIE: President's Council on Integrity and Effi-
 ciency m:  Government
 pCi/1: Picocuries Per Litre
 PCIOS: Processor Common Input/Output System
 PCM: Phase Contrast Microscopy
 PCO: Printing Control Officer
 PCON: Potential Contractor
 PCP: Pentachlorophenyl
 PCS: Permanent Change of Station
 PCS: Permit Compliance System (CWA)
 PCSC: PC Site Coordinator
 PCV: Positive Crankcase Ventilation
 PD: Position Description
 PD: Position Document
 PD: Project Description
 PDFID: Preconstruction Direct Flame lomzation
  Detection
 PDMS: Pesticide Document Management System
  (OPP)
 FDR: Particulate Data Reduction
 PE: Program Element
 PEL: Permissible Exposure Limit
 PEL: Personal Exposure Limit
 PEM: Partial Equilibrium Multimarket Model
 PEM: Personal Exposure Model
 PEPE: Prolonged Elevated Pollution Episode
 PESTAN: Pesticides Analytical Transport Solution
 PF: Potency Factor
 PF: Protection Factor
 PFT: Permanent Full Time
 PFTE: Permanent Full-Time Equivalent
 PHC: Principal Hazardous Constituent
 PHS: (US) Public Health Service
 PHSA: Public Health Service Act
 PI: Preliminary Injunction
 PI: Program Information
 PIC: Products of Incomplete Combustion
 PIC: Public Information Center
 PIGS: Pesticides in Groundwater Strategy
 PIN: Procurement Information Notice
 PIP: Public Involvement Program
 PIPQUIC: Program Integration Project Queries
  Used in  Interactive Command
 P1RG: Public Interest Research Croup
 PIRT: Pretreatment Implementation Review Task
  Force
 PIS: Public Information Specialist.
 PITS: Project Information Tracking System (OTS)
 PLIRRA: Pollution Liability Insurance  and Risk
  Retention Act
PLM: Polarized Light Microscopy
PLUVUE:  Plume Visibility Model
PM: Particulate Matter
PM: Program Manager
PM10: Particulate Matter (nominally 10m and less)
PM15: Particulate Matter (nominally 15m and less)
PMEL: Pacific Marine Environmental Laboratory
PMIP: Presidential Management Intern Program
PMIS: Personnel Management Information Sys-
  tem (OARM)
PMN: Premanufacture Notification (TSCA)
PMNF: Premanufacture Notification Form
PMR: Pollutant Mass Rate
PMRS: Performance Management and  Recogni-
  tion System (OARM) PMS- Program  Manage-
  ment System
PMS: Personnel Management Specialist
PNA: Polynuclear Aromatic Hydrocarbons
PO: Project Officer
PO: Purchase Order
POC: Point of Compliance
POC: Program Office Contacts
FOE: Point of Exposure
POGO: Pnvately-Owned/Government-Operated
POHC: Principal Organic Hazardous Constituent
POI: Point of Interception
POLREP: Pollution Report
POM: Particulate Organic Matter
POM: Polycyclic Organic Matter
26

-------
 'OTW: Publicly Owned Treatment Works
 'OV: Privately Owned Vehicle
 'P: Pay Period
 'P: Program Planning
 'PA: Pesticide Producers Association
 'PA: Planned Program Accomplishment
 >pb: Parts Per Billion
 'PC: Personal Protective Clothing
 'PE: Personal Protective Equipment
 'PIS: Pesticide Product Information System
 >pm: Parts Per Million
 'PMAP: Power Planning Modeling Application
 Procedure
 'PSP: Power Plant Siting Program
 'PT: Permanent Part Time
 ipt: Parts Per Trillion
 >pth: Parts Per Thousand
 'R: Preliminary Review
 'R: Procurement Request
 'RA: Paperwork Reduction Act
 'RA: Planned Regulatory Action
 'RM: Prevention Reference Manuals
 'RP: Potentially Responsible Party (CERCLA)
 *S: Point Source
 'SAM: Point Source Ambient Monitoring
 'SD: Prevention of Significant Deterioration
 'SE: Program Subelement
 "SES: Pretreatment Standards for Existing
 Sources
 'SI: Pollutant Standards Index
 'SI: Pounds Per Square Inch (Pressure)
 'SI: Pressure Per Square Inch
 'SIG: Pressure Per  Square Inch Gauge
 'SM: Point Source Monitoring
 'SNS: Pretreatment Standards for New Sources
 'SP: Payroll Savings Plan
 'SS: Personnel Staffing Specialist
 'STN: Pesticide Safety Team Network
 T: Part Time
 TDIS: Single Stack Meteorological Model in EPA
 UNAMAP Series
 TE: Potential to Emit
 'TFE: Polytetrafluoroethylene (Teflon)
 'TMAX: Single Stack Meteorlogical Model in EPA
 UNAMAP series
 'TPLU: Point Source Gaussian Diffusion Model
 'UC: Public  Utility Commission
 'V: Project Verification
 'VC: Polyvinyl Chloride
 'WS: Public Water Supply
 'WS: Public Water System (SDWA)
 'WSS: Public Water Supply System (SDWA)
 'Y: Prior Year
2A: Quality Assurance
2AC: Quality Assurance Coordinator
3A/QC: Quality Assistance/Quality Control
QAMIS: Quality Assurance Management and In-
 formation System
QAO: Quality Assurance Officer
QAPP: Quality Assurance Program (or Project)
 Plan
qBtu: Quadrillion British Thermal Units
QC: Quality Control
QCA: Quiet Communities Act
QCI: Quality Control Index
QCP: Quiet Community Program
QNCR: Quarterly Noncompliance Report
QCP: Quiet Community Program
QSI: Quality Step Increase
RA: Reasonable Alternative
RA: Regional Administrator
RA: Regulatory Alternatives
RA: Regulatory Analysis
RA: Remedial Action
RA: Resource Allocation
RA: Risk Analysis
RA: Risk Assessment
RAATS: RCRA Administrative Action Tracking
  System
RAC: Radiation Advisory Committee
RAC: Regional Asbestos Coordinator
RAC: Response Action Coordinator
RACM: Reasonably Available Control Measures
RACT: Reasonably Available Control Technology
RAD: Radiation Adsorbed Dose (unit of measure-
  ment of radiation adsorbed by humans)
RADM: Random Walk Advection and Dispersion
  Model
RADM: 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
RAP: Remedial Accomplishment Plan
RAP: Response Action Plan
RAPS: Regional Air Pollution Study
RARG: Regulatory Analysis  Review Group
RAS: Routine Analytical Service
RAT: Relative Accuracy Test
RB: Red Border
RBC: Red Blood Cells
RC: Regional Counsel
RC: Responsibility Center
RCC: Radiation Coordinating Council
RCDO: Regional Case Development Officer
RCP: Research Centers Program
RCRA: Resource Conservation and Recovery Act
RCRIS: Resource Conservation and Recovery In-
  formation System
RD: Remedial Design (CERCLA)
R&D: Research and Development
RD&D: Research, Development and Demonstra-
  tion
RDF: Refuse-Derived Fuel
rDNA: Recombinant DNA
RDU: Regional Decision Units
RE: Reasonable Efforts
RE: Reportable Event
REAP: Regional Enforcement Activities Plan
REE: Rare Earth Elements
REEP: Review of Environmental Effects of Pollut-
  ants
REF: Reference
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: Radio Frequency
RF: Response Factor:
RFA: Regulatory Flexibility Act
RFB: Request for Bid
RFD: Reference Dose Values
RFI: Remedial Field Investigation
RFP: Reasonable Further Programs
RI: Reconnaissance Inspection (CWA)
RI: Remedial Investigation
RIA: Regulatory Impact Analysis
RIA: Regulatory Impact Assessment
RIC:  Radon Information Center
RIC:  RTF Information Center
RICC: Retirement Information and Counseling
 Center
RICO: Racketeer Influenced and Corrupt Organi-
 zations Act
RI/FS: Remedial Information/Feasibility Study
RIM: Regulatory Interpretation Memorandum
RIN: Regulatory Identifier Number
RIP: RCRA Implementation Plan
RISC: Regulatory Information Service Center
 (OMB)
RJE: Remote Job Entry
RLL: Rapid and Large Leakage (Rate)
RMCL: Recommended Maximum Contaminant
 Level (this phrase is being discontinued in favor
 of MCLG)
RMDHS: Regional Model Data Handling System
RMIS: Resources Management Information Sys-
 tem
RMO: Records Management Officer
RMP: Revolutions Per Minute
RNA: Ribonucleic Acid
RO: Regional Office
ROADCHEM: Roadway Version that Includes
 Chemical Reactions of BI,  NOz, and Os
ROADWAY: A Model to Predict Pollutant Con-
 centrations Near a: Roadway
ROC: Record of Communication
ROD: Record of Decision (CERCLA)
ROG: Reactive Organic Gases
ROLLBACK: A Proportional Reduction Model
ROM: Regional Oxidant Model
ROMCOE: Rocky Mountain Center on the En-
 vironment
ROP: Regional Oversight Policy
ROPA: Record of Procurement Action
RP: Respirable Particulates
RP: Responsible Party
RPAR: Rebuttable Presumption Against Registra-
  tion (FIFRA)
RPM: Reactive Plume Model
RPM: Remedial Project Manager (CERCLA)
RPM: Revolutions Per Minute
RPO: Regional Planning Officer
RPO: Regional Program Officer
RQ: Reportable Quantities
RRC: Regional Response  Center
RRT: Regional Response  Team
RRT: Requisite Remedial  Technology
RSCC: Regional Sample Control Center
RSKERL: Robert S. Kerr Environmental Research
 Laboratory
RT: Regional Total
RTCM: Reasonable  Transportation Control
 Measure
RTD: Return to Duty
RTDM: Rough Terrain Diffusion Model
RTECS: Registry of Toxic Effects of Chemical Sub-
 stances
RTM: Regional Transport Model
RTF: Research Triangle Park
RUP: Restricted Use Pesticide (FIFRA)
RVP: Reid Vapor Pressure
RWC: Residential Wood Combustion
SA: Special Assistant
SA: Sunshine Act
S&A: Sampling and Analysis
S&A: Surveillance and Analysis
SAB: Science Advisory Board (AO)
SAC: Secretarial Advisory Board
SAC: Suspended and Cancelled Pesticides (FIF-
 RA)
SADAA: Science Assistant to  the Deputy Ad-
 ministrator
SAEWG: Standing Air Emissions Work Group

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SAIC: Special-Agents-In-Charge (NEIC)
SAIP: Systems Acquisition and Implementation
 Program
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
SAR: Structural Activity Relationship (of a quali-
  tative assessment)
SARA: Superfund Amendments and Reauthoriza-
  tion Act of 1986
SAROAD: Storage  and Retrieval  of Aerometric
 Data
SAS: Special Analytical Service
SAS: Statistical Analysis System
SASS: Source Assessment Sampling System
SBA: Small Business Act
SBA: Small Business Administration
SBO: Small Business Ombudsman
SC: Sierra Club
SC: Steering Committee
SCAP: Superfund Consolidated Accomplish-
 ments Plan (CERCLA)
SCAC: Support Careers Advisory  Committee
SCBA: Self-Contained Breathing Apparatus
SCC: Source Classification Code
SCFM: Standard Cubic Feet Per Minute
SCLDF: Sierra Club Legal Defense Fund
SCORPIO: Subject Content-Oriented Retriever
 for Processing Information On-Lme
SCR: Selective Catalytic Reduction
SCRAM:  State Consolidated RCRA Authorization
  Manual
SCRC: Superfund Community Relations  Coordi-
  nator
SCS: Soil Conservation Service
SCS: Supplementary Control Strategy
SCS: Supplementary Control System
SCSA: Soil Conservation Society of America
SCSP: Storm and Combined Sewer Program
SCW: Supercritical  Water Oxidation
SD: Standard Deviation
SDBE: Small Disadvantaged Business Enterprise
SDC: Systems Decision Plan
SDWA: Safe Drinking Water Act
S&E: Salaries and Expensses
SEA: State Enforcement Agreement
SEA: State/EPA Agreement
SEAM: Surface, Environment, and Mining
SEAS: Strategic Environmental Assessment Sys-
  tem
SEE: Senior Environmental Employee
SEIA: Socioeconomic Impact Analysis
SEM: Scanning Electronic Microscope
SEM: Standard Error of the Means
SEPWC:  Senate Environment and Public Works
  Committee
SERC: State Emergency Planning  Commission
SES: Secondary Emissions Standard
SES: Senior Executive Service
SES: Socioeconomic Status
SETS: Site Enforcement Tracking System
SF: Standard Form
SF: Superfund
SFA: Spectral Flame Analyzers
SFFAS: Superfund Financial Assessment Systerm
SFIREG: State FIFRA Issues Research and Evalua-
  tion Group
SHORTZ: Short Term Terrain Model
SHWL: Seasonal High Water Level
SI: International System of Units
SI: Spark Ignition
SIC: Standard Industrial Classification
SICEA: Steel Industry Compliance Extension Act
SIMS: Secondary Ion-Mass Spectometry
SIP: State Implementation Plan (CAA)'
SIS: Stay In School
SITE: Superfund Innovative Technology Evalua-
  tion
SL: Sick Leave
SLAMS: State/Local Air Monitoring Station
SLSM: Simple Line Source Model
SMCRA: Surface Mining Control and Reclamation
  Act:
SME: Subject Matter Expert
SMO: Sample Management Office
SMSA: Standard Metropolitan Statistical Area
SNA: System Network Architecture
SNAAQS: Secondary National Ambient Air Qual-
  ity Standards
SNAP: Significant  Noncompliance Action Pro-
 gram
SNARL: Suggested No Adverse Response Level
SNC: Signficant Noncompliers
SNUR: Significant New Use Rule (TSCA)
SOC: Synthetic Organic Chemicals
SOCMI: Synthetic Organic Chemicals Man-
 ufacturing Industry
SOP: Standard Operating Procedure
SOTDAT: Source Test Data
SOW: Scope of Work
SPAR: Status of Permit Application Report
SPCC: Spill Prevention,  Containment, and Coun-
  termeasure (CWA)
SPE: Secondary Particulate Emissions
SPECS: Specifications
SPF: Structured Programming Facility
SPI: Strategic Planning Initiative
SPLMD: Soil-pore Liquid Monitoring Device
SPMS: Special Purpose Monitoring Stations
SPMS: Strategic Planning and Management Sys-
  tem
SPOC: Single Point of Contact
SPS: State Permit System
SPSS: Statistical Package for the Social Sciences
SPUR: Software Package for Unique Reports
SQBE: Small Quantity Burner Exemption
SQG: Small Quantity Generator
SRAP: Superfund Remedial Accomplishment
 Plan
SRC: Solvent-Refined Coal
SRM: Standard Reference Method
SS: Settleable Solids
SS: Superfund Surcharge
SSA:  Sole Source Aquifer
SSAC: Soil Site Assimulated Capacity
SSC: State Superfund Contracts: (OSWER)
SSD: Standards Support Document
SSEIS: Standard Support and Environmental Im-
  pact Statement
SSEIS: Stationary Source Emissions and Inventory
  System
SSI: Size Selective Inlet
SSMS: Spark Source Mass Spectrometry
SSN: Social Security Number
SSO: Source Selection Official
SST: Supersonic Transport
SSURO: Stop Sale, Use and Removal Order (FIF-
  RA)
STAPPA: State and Territorial Air Pollution Pro-
  gram Administrators
STALAPCO:  State and Local Air Pollution Control
  Officials
STAR: Stability Wind Rose
STAR: State Acid Rain Projects
S/TCAC: Scientific/Technical Careers  Advisory
  Committee
STEL: Short-Term Exposure Limit
STEM: Scanning Transmission-Electron Micro-
  scopy
STN: Scientific  and Technical Information Net-
  work
STORET: Storage and Retrieval of Water-Related
  Data
STP: Sewage Treatment Plant
STP: Standard Temperature and Pressure
SUP: Standard Unit of Processing
SURE: Sulfate Regional Experiment Program
SV: Sampling Visit
SW: Slow Wave
SWC: Settlement With Conditions
SWDA: Solid Waste Disposal Act
SWIE: Southern Waste Information Exchange
SWMU: Solid Waste Management Unit
SYSOP: Systems Operator
 TA: Travel Authorization
 T&A: Time and Attendance
 TALMS: Tunable Atomic Line Molecular Spec-
  troscopy
 TAMS: Toxic Air Monitoring System
 TAMTAC: Toxic Air Monitoring System Advisory
  Committee
 TAP: Technical Asssistance Program
 TAPDS: Toxic Air Pollutant Data System
 TAPP: Time and Attendance, Payroll,  and Per-
  sonnel
 TBT: Tributyltin
 TC: Target Concentration
 TC: Technical Center
 TC: Toxic Concentration:
 TCDD: Dioxin (Tetrachlorodibenzo-p-dioxin)
 TCDF: Tetrachlorodibenzofurans
 TCE: Trichloroethylene
 TCLP: Total Concentrate Leachate Procedure
 TCLP: Toxicity Characteristic Leachate Procedure
 TCM: Transportation Control Measure
 TCP: Transportation Control Plan
 TCP: Trichloroethylene
 TCP: Trichloropropane
 TCRI: Toxic Chemical Release Inventor)'
 TD: Toxic Dose
 TDS: Total Dissolved Solids
 TDY: Temporary Duty
 TEAM: Total Exposure Assessment Model
 TEC: Technical Evaluation Committee
 TEG: Tetraethylene Glycol
 TEGD:  Technical Enforcement Guidance Docu-
  ment
 TEM: Texas Episodic Model
 TEM: Transmission Electron Microscopy
 TEP: Technical Evaluation Panel
 TES: Technical Enforcement Support
 TEXIN: Texas Intersection Air Quality Model
 TFT: Temporary  Full Time
 TFTE: Temporary Full-Time Equivalent
 TGO: Total Gross Output
 THC: Total Hydrocarbons
 THM: Trihalomethane
 TI: Temporary Intermittent
 TI: Therapeutic Index
 TIBL: Thermal Internal Boundary Layer
 TIC: Technical Information Coordinator
 TIC: Tentatively  Identified Compounds
 TIM: Technical Information Manager
 TIP: Transportation Improvement Program
 TISE: Take It Somewhere Else (Solid Waste Syn-
  drome. See NIMBY)
 TITC: Toxic Substance Control Act Interagency
  Testing.  . Committee
 TLV: Threshold Limit Value
 TMI: Three Mile Island
 TNT: Trinitrotoluene
 TO: Task Order
 TO: Travel Order
 TOA: Trace Organic Analysis
 TOC: Total Organic Carbon
 TOC: Total Organic Compound
 TOT: Time-of-Travel
 28

-------
 TOX: Tetradichloroxylene
 TPC: Testing Priorities Committee
 TPI: Technical Proposal Instructions
> TPQ: Threshold Planning Quantity
 TPSIS: Transportation Planning Support Informa-
   tion System.
 TPTH: Tnphenyltinhvdroxide
 TPY: Tons Per Year
 T-R: Transformer-Rectifier
 TRC: Technical Review  Committee
 TRD: Technical Review Document
 TRI: Toxic Release Inventory
 TRIP: Toxic Release Inventory Program
 TRLN: Triangle Research Library Network
 TRO: Temporary Restraining Order
 TS: Toxic Substances
 TSA: Technical Systems Audit
 TSCA: Toxic Substances Control Act
 TSCATS: TSCA Test Submissions Database (O rS)
 TSCC: Toxic Substances Coordinating Committee
 TSD: Technical Support Document
 TSDF; Treatment, Storage, and Disposal Facility
   (OTS)
 TSDG: Toxic Substances Dialogue Group
 TSM: Transportation System Management
 TSO: Time Sharing Option
 TSP: Teleprocessing Services Program
 TSP: Thrift Savings Plan
 TSP: Total Suspended Particulates
 TSS: Terminal Security System
 TSS: Total Suspended (non-filterable) Solids
 TTFA:  Target Transformation Factor Analysis
 TTHM: Total Trihalomethane
 TTO: Total Toxic Organics
 TTY: Teletypewriter
 TVA: Tennessee Valley Authority
 TWA: Time Weighted Authority.
 TZ: Treatment Zone
 u

 UAC: User Advisory Committee
 UAM: Urban Airshed Model
 UAPSP: Utility Acid Precipitation Study Program
 UAQI: Uniform Air Quality Index
 UARG: Utility Air Regulatory Group
 UCC: Ultra Clean Coal
 UCL: Upper  Control Limit
 UDMH: Unsymmetrical Dimethyl Hydrazine
 UEL: Upper  Explosive Limit
 UFL: Upper Flammability Limit
 UIC: Underground Injection Control
 UL: Underwriters' Laboratories
 ULP: Unfair  Labor Practices
 UMTA: Urban Mass Transportation Administra-
   tion
 UMTRCA: Uranium Mill Tailings Radiation Con-
   trol Act
 UN:  United Nations
 UNAMAP: Users' Newtork for Applied Modeling
   of  Air Pollution
 UNEP: United Nations Environment Program
 UNESCO: United Nations Educational, Scientific
   and Cultural:  Organization
 UNIDO: United Nations Industrial Development
   Organization
 USAO: United States Attorney's Office
 USBM: United States Bureau of Mines
 USC: Unified Soil Classification
 USC: United States Code
 USCA: United States Code Annotated
 USDA: United States Department of Agriculture
 USDOI: United States Department of the Interior
 USDW: Underground Sources of Drinking Water
 USEPA: United States Environmental Protection
  Agency
 USFS: United States Forest Service
USGS: United States Geological Survey
USNRC: United States Nuclear Regulatory Com-
  mission
USPHS: United States- Public Health Service
USPS: United States Postal Service
UST: Underground Storage Tank
UTM: Universal Transverse Mercator:
UTP: Urban Transportation Planning
UV: Ultraviolet
UZM: Unsaturated Zone Monitoring
V

VA: Veterans Administration
VALLEY: Meteorological Model to Calculate Con-
  centrations .  : on Elevated Terrain
VCM: Vinyl Chloride Monomer
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 Atmos-
  phere
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 Deposition Task
 Force
WAP: Waste Analysis Plan (RCRA)
WB: Wet Bulb
WB: World Bank
WBC: White Blood Cells
WBE: Women's Business Enterprise
WCED: World Commissin on Environment and
 Development
WDROP: Distribution Register of Organic Pollut-
 ants in Water
WENDB: Water Enforcement National Data Base
WERL: Water Engineering Research Laboratory
WG: Wage Grade
WG: Work Group
WGI: Within Grade Increase
WHO: World Health Organization
WHWT: Water and Hazardous Waste Team
WIC: Washington Information Center
WICEM: World Industry Conference on Environ-
 mental Management
WISE: Women In Science and Engineering
WL: Warning Letter
WL: Working Level (radon measurement)
WLA/TMDL: Waste Load Allocation/Total Max-
 imum Daily Load
WLM: Working Level Months:
WMO: World Meteorological Organization
WPCF: Water Pollution Control Federation
WRC: Water Resources Council
WRDA: Water Resources Development Act
WRI: World Resources Institute
WS: Work Status
WSF: Water Soluble Fraction
WSRA: Wild and Scenic Rivers Act
WSTB: Water Sciences and Technology Board
WSTP: Wastewater Sewage Treatment Plant
WWEMA: Waste and Wastewater Equipment
 Manufacturers' Association
WWF: World Wildlife Fund
WWTP: Wastewater Treatment Plant
Y-Z

YTD: Year to Date
ZBB: Zero Base Budgeting
ZHE: Zero Headspace Extractor
ZOI: Zone of Incorporation
ZRL: Zero Risk Level
                  '<.-,
                  r.;
                                                                                                                                       29

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