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A—Scale Sound Level: A measurement
of sound approximating the sensitivity
of the human ear, used to note the
intensity or annoyance level of sounds.

Abandoned Well: A well whose use has
been  permanently  discontinued  or
which is in a state of such disrepair
that it cannot be used for its intended
purpose.

Abatement: Reducing the  degree or
intensity of, or eliminating, pollution.

Absorbed  Dose:  The  amount  of  a
chemical that enters the body of an
exposed organism.

Absorption:  The uptake  of  water or
dissolved chemicals  by  a cell  or an
organism (as  tree roots absorb  dis-
solved nutrients in soil.)

Accident Site: The location of an unex-
pected occurrence, failure or loss, ei-
ther at a plant or along a transporta-
tion route, resulting in a  release of
hazardous materials.

Acclimatization: The physiological and
behavioral adjustments of an organism
to changes in its environment.

Acid Deposition: A complex chemical
and atmospheric  phenomenon that
occurs when emissions of sulfur and
nitrogen compounds  and other sub-
stances are transformed by chemical
processes in the atmosphere, often far
from the original sources, and then de-
posited  on earth in either wet or dry
form.  The wet forms, popularly called
"acid rain," can fall as rain, snow, or
fog. The .dry forms are acidic gases or
p articulates.

Acid Mine Drainage: Drainage of water
from areas that have been mined for
coal or other mineral ores. The water
has a low  pH because of its contact
with  sulfur-bearing  material  and is
harmful to aquatic organisms.

Acid Neutralizing Capacity: Measure of
ability of water or soil to resist chang-
es in pH.
Acid Rain:  (See: acid deposition)

Acidic: The condition of water or soil
that contains a sufficient amount of
acid substances to lower the pH below
7.0.

Action Levels:   1. Regulatory levels
recommended by EPA for enforcement
by  FDA and  USDA when pesticide
residues occur in food or feed commodi-
ties for reasons other than the direct
application of the pesticide. As opposed
 to "tolerances" which are established
 for residues  occurring as a direct re
 suit of proper usage, action levels are
 set for inadvertent residues resulting
 from previous legal use or accidental
 contamination. 2.  In  the  Superfund
 program, the existence of a contami-
 nant concentration in the environment
 high enough to warrant action or trig-
 ger  a response under  SARA and the
 National Oil and Hazardous Substanc-
 es Contingency Plan. The term is also
 used in other regulatory programs.
 (See: tolerances.)
 Activated Carbon: A highly adsorbent
 form of  carbon used to remove odors
 and toxic  substances  from liquid or
 gaseous emissions. In waste treatment
 it is used to remove dissolved organic
 matter  from waste water. It is  also
 used in motor vehicle evaporative con-
 trol systems.
 Activated Sludge: Product that results
'when primary effluent is  mixed with
 bacteria-laden sludge  and then agi-
 tated and aerated to promote biological
 treatment, speeding the breakdown of
 organic matter in raw sewage undergo-
 ing secondary waste treatment.
 Activator A chemical added to a pes-
 ticide to increase its activity.
 Active Ingredient: In any pesticide
 product, the component that kills, or
 otherwise controls, target pests. Pes-
 ticides are regulated primarily on the
 basis of  active ingredients.
 Activity Plans: Written procedures in a
 school's  asbestos-management  plan
 that detail the steps a Local Education
 Agency (LEA) will follow in performing
 the  initial  and  additional cleaning,
 operation  and maintenance-program
 tasks; periodic surveillance; and rein-
 spections required  by the Asbestos
 Hazard  Emergency  Response  Act
 (AHERA).
 Acute Exposure: A single exposure to a
 toxic substance which results in severe
 biological harm or death.  Acute expo-
 sures are usually characterized as last-
 ing no longer than a day, as compared
 to longer, continuing exposure over a
 period of time.
 Acute Tarititv: The ability of a sub-
 stance to cause poisonous effects re-
 sulting in severe biological harm or
 death soon after a single  exposure or
 dose. Also, any severe poisonous effect
 resulting from  a  single  short-term
 exposure to a toxic substance.  (See:
 chronic toxicity, toxitity.)
Adaptation: Changes in an organism's
structure or habits that help it adjust
to its surroundings.

Add-on Control Device: An air pollu-
tion  control  device  such as carbon
absorber or incinerator  that reduces
the pollution in  an exhaust gas. The
control device usually does not affect
the process being controlled and  thus
is "add-on" technology, as opposed to a
scheme  to control pollution  through
altering the basic process itself.

Adequately Wet: Asbestos-containing
material that is  sufficiently mixed or
penetrated with  liquid to prevent the
release of  particulates.

Administrative Order On Consent: A
legal agreement signed by EPA and an
individual, business,  or  other entity
through which the violator agrees to
pay for correction of violations,  take
the  required corrective  or  cleanup
actions, or refrain from, an activity. It
describes the actions to be taken, may
be subject to a comment period, applies
to civil actions, and can be enforced in
court.

Administrative  Order A legal  docu-
ment signed by EPA directing an indi-
vidual, business, or other entity to take
corrective  action or  refrain from an
activity'. It describes the violations and
actions to be taken, and can be en-
forced in  court.  Such orders may be
issued, for example, 'as a result of an
administrative complaint whereby the
respondent is ordered to pay a penalty
for violations of a statute.

Administrative Procedures Act: A law
that spells out procedures and requir'
ements related to the promulgation of
regulations.

Administrative Record: All documents
which EPA considered or relied on in
selecting  the response   action  at  a
Superfund site,  culminating in the
record of decision for remedial action;
an  action memorandum for removal
actions.

Adsorption: An  advanced method of
treating waste in which activated car-
bon  removes organic matter   from
wastewater.

Adulterants:  Chemical impurities or
substances that  by law do not belong
in a food,  or pesticide.

Adulterated:  1.  Any pesticide whose
strength or purity falls below the qual-
ity stated on its label. 2. A food.feed, or
product that  contains illegal pesticide
residues.

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Advanced Treatment: A level of waste-
water treatment more stringent than
secondary treatment; requires an 85-
percent reduction in conventional pol-
lutant concentration or a significant
reduction in nonconventipnal pollut-
ants.
Advanced Wastewater Treatment: Any
treatment of sewage that goes beyond
the secondary or biological water treat-
ment stage and includes the removal of
nutrients such  as  phosphorus and
nitrogen and a high percentage of sus-
pended solids. (See: primary, secondary
treatment.)
Advisory. A non-regulatory document
that communicates risk information to
those who may have to make risk man-
agement decisions.
Aerated Lagoon:  A  holding and/or
treatment pond that speeds  up the
natural process of biological decomposi-
tion of  organic waste by stimulating
the growth and activity of bacteria that
degrade organic waste.
Aeration: A process which promotes
biological degradation of organic mat-
ter in water. The process may be pas-
sive (as when waste is exposed to air),
or active (as when a mixing or bub-
bling device introduces the air).
Aeration Tank: A chamber used to in-
ject air into  water.
Aerobic Treatment: Process by which
microbes decompose complex organic
compounds in the presence of oxygen
and use the liberated energy for re-
production and growth. (Such process-
es include extended aeration, trickling
filtration,  and  rotating  biological
contactors.)
Aerobic: Life or processes that require,
or are not destroyed by, the presence of
oxygen. (See: anaerobic.)
Aerosol: A suspension of liquid or solid
particles in a gas.
Affected Public The people who live
and/or work near a hazardous waste
site or other source of pollutant emis-
sions.
Afterburner: In incinerator technology,
a burner located so that the  combus-
tion gases are made to pass through its
flame in order to remove smoke and.
odors.   It may be attached to or  be
separated from the incinerator proper.
Age Tank:  A tank  used to store a
chemical solution of known concentra-
tion for feed .to a chemical feeder. Also
called a day tank.
Agent Orange: A toxic herbicide and
defoliant used in the Vietnam conflict,
containing 2,4,5-trichlorophenoxyacetic
acid (2,4,5-T) and 2-4 dichlorophenoxy-
acetic acid (2,4-D) with trace amounts
of dioxin.

Agricultural   Pollution:  Farming
wastes, including runoff and leaching
of pesticides and  fertilizers; erosion
and dust from plowing; improper dis-
posal of animal manure and carcasses;
crop residues, and debris.

Agro-ecosystem: Land used for crops,
pasture, and livestock;  the adjacent
uncultivated land that supports other
vegetation and wildlife; and the associ-
ated atmosphere, the underlying soils,
groundwater, and drainage networks.

AHERA Designated Person (ADP): A
person designated by  a Local Educa-
tion Agency to ensure that the AHERA
requirements for asbestos management
and abatement are properly  imple-
mented.

Air Binding: Situation where air enters
the filter media and harms both the
filtration and backwash processes.

Air Changes Per Hour (ACH> The
movement of a volume of air in a given
period of time;  if a house has one air
change per hour, it means that all of
the air in the house will be replaced in
a one-hour period.

Air Contaminant: Any particulate mat-
ter, gas, or combination thereof, other
than water vapor. (See: air pollutant.)

Air Curtain: A method of containing oil
spills. Air bubbling through a perfo-
rated pipe causes an upward water
flow that slows the spread of  oil.  It
«•*" also be used to stop fish from en-
tering polluted water.

Air Gap: Open vertical gap or empty
space that separates  drinking water
supply to be protected from another
water system in a treatment plant or
other location. The open gap protects
the drinking water from contamination
by backflow or backsiphonage.

Air Mass: A large volume of air with
certain meteorological or polluted char-
acteristics, e,g,  a  heat inversion  or
smogginess, while in one location. The
characteristics cfi" change as the air
mass moves away.
Air Monitoring: (See: monitoring)

Air Padding: Pumping dry air into a
container to assist with the withdrawal
of liquid or to force a liquified gas such
as chlorine out of the container.
Air Plenum: Any space used to convey
air in a building, furnace, or structure.
The space above a suspended ceiling is
often used as an air plenum.

Air Pollutant:  Any substance in air
that could, in high enough concentra-
tion, harm man, other animals, vegeta-
tion, or material. Pollutants may in-
clude almost any natural or artificial
composition of airborne matter capable
of being airborne. They may be in the
form of solid particles, liquid droplets,
gases, or in combination thereof. Gen-
erally, they fall into two main groups:
(1) those emitted directly from identi-
fiable sources and (2) those  produced
in the  air by interaction between two
or more primary pollutants, or by reac-
tion with normal atmospheric constitu-
ents, with or without photoactivation.
Exclusive of pollen,  fog, and  dust,
which are of natural origin, about 100
contaminants have been identified and
fall into the following categories: sol-
ids, sulfur compounds, volatile organic
chemicals, nitrogen compounds, oxygen
compounds, halogen compounds, radio-
active compounds, and odors.

Air Pollution Episode: A period of ab-
normally  high  concentration of  air
pollutants, often due to low winds and
temperature inversion, that can cause
illness and death. (See: episode, pollu-
tion.)'

Air Pollution Control Device: Mecha-
nism or equipment that cleans emis-
sions generated by an incinerator by
removing pollutants that would other-
wise be released to the atmosphere.

Air Pollution: The presence of contami-
nant or pollutant substances in the air
that do not disperse properly and in-
terfere with human health or welfare,
or produce other harmful environmen-
tal effects.

Air Quality Control Region: Federally
designated area that is  required to
meet and maintain federal ambient air
quality standards. May include nearby
locations in the same  state or nearby
states that share common air pollution
problems-
Air Quality Criteria:  The  levels  of
pollution  and  lengths of  exposure
above which adverse health and wel-
fare effects may occur.

Air Quality Standards: The level of
pollutants prescribed by  regulations
that may not be exceeded  during  a
given time in a defined area.

Air Stripping: A treatment system that
removes  volatile organic compounds
(VOCs)  from   contaminated ground

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water or surface water by forcing an
airstream through the water and cau-
sing the compounds to evaporate.

Air Tories: Any air pollutant for which
a national ambient air  quality stan-
dard (NAAQS) does not exist (i.e., ex-
cluding ozone, carbon monoxide, PM-
10, sulfur dioxide, nitrogen oxide) that
may reasonably be anticipated to cause
cancer, developmental effects, repro-
ductive dysfunctions, neurological dis-
orders, heritable  gene mutations, or
other serious or irreversible chronic or
acute health effects in humans.
Airborne Particulates: Total suspended
particulate matter found in the atmo-
sphere as solid particles or liquid drop-
lets.   Chemical  composition  of
particulates varies widely, depending
on location and time of year. Airborne
particulates include:  windblown dust,'
emissions from industrial processes,
smoke  from the burning of wood and
coal, and motor vehicle or non-road
engine exhausts, exhaust of motor
vehicles.

Airborne Release: Release of any chem-
ical into the air.

Alachlor A herbicide, marketed under
the trade name Lasso, used mainly to
control weeds in corn  and soybean
fields.

Alar Trade name for daminozide, a
pesticide that makes apples redder,
firmer, and less likely to drop off trees
before growers are ready to pick them.
It is also  used to a  lesser extent on
peanuts, tart cherries, concord grapes,
and other fruits.

Aldicarb: An insecticide sold under the
trade name Temik. It ia made from
ethyl isocyanate.

Algae: Simple rootless plants that grow
in sunlit waters in proportion to the
amount of available nutrients. They
can affect water quality adversely by
lowering the dissolved oxygen in the
water. They are food for fish and small
aquatic animals.

Algal Blooms: Sudden spurts of algal
growth, which can affect water quality
adversely  and indicate  potentially
hazardous  changes  in  local  water
chemistry.

Algicide: Substance or chemical used to
specifically to kill or control algae.

Alkaline: The condition of water or soil
which contains a suffice nt amount of
alkali substance to raise the pH above
7.0.
 Alkalinity: The capacity of water to
 neutralize acids.
 Alluvial: Relating to  and/or sand de-
 posited by flowing water.
 Alternate Method: Any method of sam-
 pling and analyzing for an air pollut-
 ant that is not a reference or equiva-
 lent method but that has been demon-
 strated in specific cases-to EPA's satis-
 faction-to produce results adequate for
 compliance monitoring.
 Alternative Fuels: Substitutes for tra-
 ditional liquid, oil-derived motor vehi-
 cle fuels like  gasoline and diesel. In-
 cludes methanol, ethanol, compressed
 natural gas, and others.
 Alternative Remedial Contract Strate-
 gy Contractors: Government contrac-
 tors who provide project management
 and technical services to support reme-
 dial response  activities at National
 Priorities List sites.
 Ambient Air  Any unconfined portion
 of the atmosphere: open air, surround-
 ing air.
 Ambient Air Quality Standards: (See:
 Criteria Pollutants and National Ambi-
 ent Air Quality Standards.)
 Ambient Temperature: Temperature of
. the surrounding air or other medium.
 Amprometric Titration: A way of mea-
 suring concentrations of certain sub-
 stances in water using an electric cur-
 rent that flows during a chemical reac-
 tion.
 Anaerobic A life or process that occurs
 in, or is not destroyed by, the absence
 of oxygen.
 Anaerobic Decomposition: Reduction of
 the net energy level and  change in
 chemical composition of organic matter
 caused by microorganisms  in an oxy-
 gen-free environment.
 Animal Studies: Investigations using
 animals as surrogates for humans with
 the expectation that the  results  are
 pertinent to humans.
 Antagonism: Interference or inhibition
 of the effect of one chemical by the
 action of another.
 Antarctic "Ozone Hole": Refers to the
 seasonal depletion of ozone in a large
 area over Antarctica.
 Anti-Degradation Clause: Part of fed-
 eral air  quality and water quality
 requirements prohibiting deterioration,
 where pollution levels are above the
 legal limit.
Applicable or Appropriate  Require-
ments (ARARs):  Any state or federal
statute that pertains to protection of
human life and the environment  in
addressing specific conditions or use of
a particular cleanup technology  at a
Super-fund site,

Aqueous: Something made up of, simi-
lar to, or containing water.

Aquifer  An  underground geological
formation, or group of formations, con-
taining usable amounts of ground water
that can supply wells and springs.

Architectural Coatings: Coverings such
as paint and roof tar that are used on
enteriors of buildings.

Area of Review:  In the UIC program,
the area surrounding an injection well
that is reviewed during the permitting
process to determine if flow between
aquifers will be  induced by the injec-
tion operation.

Area Source: Any small source of non-
natural air pollution that is released
over a relatively  small area but which
cannot be classified as a point source.
Such sources may include vehicles and
other  small engines, small businesses
and household activities.

Aromatic: A type of hydrocarbon, such
as benzene or toluene, added to gaso-
line hi order to increase octane. Some
aromatics are toxic.

Arsenicals: Pesticides containing ar-
senic.

Artesian (Aquifer or Well): Water held
under pressure hi porous rock or soil
confined  by  impermeable geological
formations.

Asbestos:  A mineral  fiber that can
pollute air or water and cause cancer
or asbestosis  when  inhaled. EPA has
banned or severely restricted its use in
manufacturing and construction.

Asbestos  Abatement:  Procedures  to
control fiber release from asbestos-con-
taining materials in a  building or to
remove them entirely, including remov-
al,  encapsulation,  repair, enclosure,
encasement, and operations and main-
tenance programs.

Asbestos-Containing Waste Materials
(ACWM):  Mill tailings or any waste
that contains commercial asbestos and
is generated by a source covered by the
Clean Air Act Asbestos NESHAPS.

Asbestosis: A disease associated with
inhalation of asbestos fibers. The dis-
ease  makes  breathing  progressively
more  difficult and can be fatal.

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Asbestos Program Manager A building
owner or  designated  representative
who supervises all aspects of the facili-
ty asbestos management and control
program.

Ash: The mineral content of a product
remaining after complete combustion.

Assay; A test for a specific chemical or
effect.

Assessment: In the asbestos-in-schools
program, the evaluation of the physical
condition and potential for  damage of
all friable asbestos containing materi-
als and thermal insulation systems.

Assimilation: The ability of a body of
water to purify itself of pollutants.

Assimilative Capacity: The capacity of
a natural  body of water  to  receive
waste waters or toxic materials without
deleterious effects and without damage
to aquatic life or humans who consume
the water.

Association of Boards of Certification:
An  international organization repre-
senting boards which certify the opera-
tors  of waterworks  and wastewater
facilities.

Attainment Area: An area considered
to have air quality as good as or better
than the national ambient air quality
standards as defined in the Clean Air
Act.  An area may be  an attainment
area for one pollutant and a non-at-
tainment area for others.

Attenuation: The process by which  a
compound is reduced in concentration
over time, through absorption, adsorp-
tion,  degradation,   dilution,  and/or
transformation.

Attractant: A chemical or agent that
lures insects or other pests by stimu-
lating their sense of smell.

Attrition: Wearing or grinding down of
a substance by  friction.   Dust  from
such processes contributes to air pollu-
tion.

Availability Session: Informal meeting
at a  public location where  interested
citizens can talk-with EPA and  state
officials on  a one-to-one basis.

Available Chlorine: A measure of the
amount of chlorine available in chlori-
nated lime, hypochlorite compounds,
and other materials used as a source of
chlorine when compared with that of
liquid or gaseous chlorines.
B

Back Pressure: A pressure that can
cause water to backflow into the water
supply when  a user's  waste water
system is at  a higher pressure than
the public system.

Backflow/Back Siphonage: A  reverse
flow condition created by a difference
in water pressures that  causes water
to flow back into the distribution pipes
of a drinking  water supply from any
source other than the intended one.
Background Level: In air pollution con-
trol, the concentration of air pollutants
in' a definite area during  a fixed period
of time prior to the starting up or on
the stoppage  of a source of emission
under  control. In . toxic  substances
monitoring, the average presence in
the environment, originally referring to
naturally occurring phenomena.
Backwashing:  Reversing the  flow of
water back through the filter media to
remove entrapped solids.
BACT-Best Available Control Technol-
ogy: An emission limitation based on
the maximum degree  of emission re-
duction  (considering energy, environ-
mental, and economic impacts) achiev-
able through application of production
processes and  available methods, sys-
tems, and techniques.  BACT does not
permit emissions in excess of those
allowed under any applicable Clean
Air Act provisions. Use  of the BACT
concept is allowable on a case by case
basis for major new or modified emis-
sions .sources in attainment areas and
applies to each regulated pollutant.
Bacteria: (Singular bacterium) Micro-
scopic living organisms that can aid in
pollution control by metabolizing or-
ganic matter  in sewage, oil spills or
other pollutants. However, bacteria in
soil, water or  air can also cause hu-
man,  animal  and plant health prob-
lems.
Baffle: A flat board or  plate, deflector,
guide, or similar device constructed or
placed in flowing water  or slurry sys-
tems to cause more uniform flow veloc-
ities to absorb energy and to divert,
guide, or agitate liquids.
                         <;
Raff|a Chamber In incinerator design,
a chamber designed to promote the set-
tling of fly ash and coarse particulate
matter  by Changing  the direction
and/or reducing the  velocity  of the
gases produced by the combustion of
the refuse or sludge.
(greater than 20 microns in diameter)
particles. This device operates like the
bag of an  electric vacuum  cleaner,
passing the air and smaller particles
while entrapping the larger ones.

Bailer A long pipe with a valve at the
lower end, used to remove slurry from
the bottom  or side of  a well as it is
being drilled.

Ruling- Compacting solid waste into
blocks to reduce volume and simplify
handling.

Ballistic Separator  A machine that
sorts organic from inorganic matter for
composting.

Band Application: The spreading of
chemicals over, or next to, each row of
plants in a field.

Banking: A system for recording quali-
fied air emission reductions for later
use in bubble, offset, or netting trans-
actions. (See: emissions trading.)

Bar Screen: In wastewater treatment,
a device used to remove large solids.

Barrier Coating(s): A layer of a materi-
al that obstructs  or prevents passage
of something through a surface that is
to be protected, e.g. grout, caulk, or
various sealing compounds; sometimes
used with polyurethane membranes to
•prevent corrosion or oxidation of metal
surfaces, chemical impacts on various
materials, or, for example, to prevent
radon   infiltration  through  walls,
cracks, or joints in a house.

Basal Application: In  pesticides, the
application  of a chemical on plant
stems or tree trunks, just above the soil
line.

Bed Load: Sediment particles  resting
on or near the channel bottom that are
pushed or rolled  along by the  flow of
water.

BEN: EPA's computer  model for ana-
lyzing a violator's economic gain from
not complying with the law.
Bench
                                                Filter:  Large  fabric bag,
                                      usually made of glass fibers, used to
                                      eliminate  intermediate  and   large
           i Testa: Laboratory testing
of potential cleanup technologies (See:
treatability studies.)
Beryllium: An airborne metal hazard-
ous to human health when inhaled. It
is discharged by  machine shops, ce-
ramic  and  propellant  plants,  and
foundries.
Best  Available  Control  Measures
(BACM): A term used to refer to the
most effective measures (according to
EPA guidance) for controlling small or
dispersed participates from sources
such as roadway dust, soot and  ash

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from woodstoves and open burning of
rush, timber, grasslands, or trash.

Beat Demonstrated Available Technolo-
gy (BDAT): As identified by EPA, the
most effective commercially available
means of treating  specific types of
hazardous  waste.  The  BDATs  may
change with advances  in  treatment
technologies.

Best  Management  Practice  (BMP):
Methods that have been determined to
be the most effective, practical means
of preventing or reducing pollution
from non-point sources.

Bimetal:  Beverage  containers  with
steel bodies  and aluminum tops;  han-
dled differently from pure aluminum in
recycling.
Bioaccumulants: Substances that in-
crease in concentration in living organ-
isms as they take in contaminated air,
water, or food because the substances
are very slowly metabolized  or ex-
creted. (See: biological magnification.)

Bioassay: Study of living organisms to
measure the effect of a substance, fac-
tor, or condition by comparing before-
and-after exposure or other data.

Biochemical Oxygen Demand (BOD): A
measure of the amount of oxygen con-
sumed in the biological processes that
break down organic matter in water.
The greater  the BOD, the greater the
degree of pollution.

Bioconcentration: The accumulation of
a chemical in tissues of a fish or other
organism to  levels greater than in the
surrounding medium.

Biodegradable: Capable of decomposing
rapidly under natural conditions.

Biodiversity: Refers to the variety and
variability among living organisms and
the ecological complexes in which they
occur. Diversity can be defined as the
number of  different items and their
relative  frequencies.  For biological
diversity, these items are organized at
many levels, ranging from complete
ecosystems to the biochemical struc-
tures that are the molecular basis of
heredity.  Thus, the term encompasses
different ecosystem, species, and genes.


Biological Control: In pest control, the
use of animals and organisms that eat
or otherwise kill or put-compete pests.

Biological Magnification: Refers to the
process  whereby  certain  substances
such as  pesticides  or heavy metals
move up the food chain,  work their
way into rivers or lakes, and are eaten
by  aquatic organisms  such as fish,
which in turn are eaten by large birds,
animals or humans. The substances
become concentrated in .tissues or in-
ternal  organs as they move up the
chain. (See: bioaccumulative.)

Biological Oxidation: Decomposition of
complex organic materials by microor-
ganisms. Occurs  in self-purification of
water bodies  and in activated  sludge
wastewater treatment.
Biological Oxygen Demand (BOD): An
indirect measure of the concentration
of  biologically  degradable  material
present in organic wastes. It usually
reflects the  amount of oxygen con-
sumed in five days by biological pro-
cesses breaking down organic waste.
Biological Treatment:  A treatment
technology that uses bacteria to con-
sume organic waste.
Biologicals:  Vaccines,  cultures  and
other preparations made from living
organisms and their products, intended
for  use in diagnosing, immunizing, or
treating humans or animals, or in
related research.
Biomass: All of the living material in a
given area; often refers to vegetation.
Biome:  Entire community of living
organisms in a single major ecological
area. (See: biotic community.)
BJomonitoring: 1. The  use of living
organisms to test the  suitability  of
effluents for discharge into receiving
waters and to test the quality of such
waters  downstream from the  dis-
charge.  2. Analysis  of blood,  urine,
tissues, etc., to measure chemical expo-
sure in humans.
Bioremediation: Use of living  organ-
isms to clean up oil spills or remove
other pollutants  from soil, water, or
wastewater; use of organisms such as
non-harmful insects to remove agricul-
tural pests or counteract diseases  of
trees, plants,  and garden soil.
Biosphere: The portion of Earth and its
atmosphere that can support life.
Biostabilizer:  A machine that converts
solid waste into  compost by grinding
and aeration.
Biota: The animal  and plant life of a
given region.
Biotechnology: Techniques that use
living organisms or parts of organisms
to produce a variety of products (from
medicines to  industrial enzymes) to
improve plants or animals or to devel-
op microorganisms  to  remove toxics
from bodies of water, or act as pesti-
cides.

Biotic Community: A naturally occur-
ring assemblage of plants and animals
that live in the same environment and
are mutually sustaining and interde-
pendent.(See: biome.)

Biotransformation:  Conversion of a
substance  into other compounds by
organisms; includes biodegredation.

Blackwater. Water that contains ani-
mal, human, or food waste.
Blood Products: Any product derived
from human blood,  including but not
limited to blood plasma, platelets, red
or white  corpuscles, and  derived li-
censed products such as interferon.

Bloom: A proliferation of algae and/or
higher aquatic plants  in  a body of
water; often related to pollution, espe-
cially  when  pollutants   accelerate
growth.

BODS: The amount of dissolved oxygen
consumed in five days by biological
processes breaking down organic mat-
ter.

Bog: A type of wetland that accumu-
lates appreciable  peat  deposits. Bogs
depend primarily on precipitation for
their water source, and are usually
acidic and rich in plant residue with a
conspicuous mat of living green moss.

Boom:  1.  A floating device used to
contain  oil on a body of water.  2. A
piece of equipment used to apply pes-
ticides from a tractor or truck.

Botanical Pesticide:  A pesticide whose
active ingredient  is a plant-produced
chemical such as nicotine or  strych-
nine. Also called a plant-derived pesti-
cide.

Bottle Bill:  Proposed or enacted leg-
islation  which requires a  returnable
deposit on beer or soda containers and
provides for retail store or other re-
demption. Such legislation  is designed
to discourage use of throwaway con-
tainers.
Bottom Ash: The non-airborne combus-
tion residue from burning pulverized
coal in  a  boiler; the material which
falls to the bottom of the boiler and is
removed mechanically; a concentration
of  the  non-combustible  materials,
which may include toxics.

Bottom  Land Hardwoods:  Forested
freshwater wetlands adjacent to rivers
in the  southeastern United  States,

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6
especially valuable for wildlife breed-
ing, nesting and habitat.

Brackish: Mixed fresh and salt water.

Breakpoint  Chlorination: Addition of
chlorine  to  water until the chlorine
demand has been satisfied.

Breakthrough: A crack or break in a
filter  bed that allows the passage of
floe or particulate matter through a
filter; will cause an increase in filter
effluent turbidity.

Brine Mud: Waste material, often asso-
ciated with well-drilling or mining,
composed of mineral salts or other
inorganic compounds.

Broadcast Application: The spreading
of pesticides over an entire area.

Bubble: A system under which existing
emissions sources can propose alter-
nate means to  comply with a set of
emissions limitations; under the bubble
concept, sources can control more than
required at one emission point where
control costs are relatively low in re-
turn for a comparable relaxation of
controls  at  a second  emission point
where costs are higher.

Bubble Policy: (See: emissions trading.)

Buffer A solutiuon or liquid  whose
chemical makeup neutralizes acids or
bases without a great change in pH.

Buffer Strips: Strips of grass or other
erosion-resisting vegetation between or
below cultivated strips or fields.

Building Cooling Load: The  hourly
amount of heat that must be removed
from  a  building  to maintain  indoor
comfort (measured in British Thermal
Units BTUs).
Bulk Sample: A small portion (usually
thumbnail size) of a suspect asbestos-
containing building material collected
by an asbestos inspector for laboratory
analysis to determine asbestos content.

Bulky Waste: Large items of waste
materials, such as appliances, furni-
ture, large auto parts, trees, stumps.

Burial Ground (Graveyard): A disposal
site for radioactive waste  materials
that uses earth or water as a shield.
By-product:  Material,  other than  the
principal product, generated as a con-
sequence of an industrial process.
Cadmium (Cd> A heavy metal element
that accumulates in the environment.
Cancellation: Refers to Section 6 (b) of
the Federal Insecticide, Fungicide and
Rodenticide Act (FIFRA) which autho-
rizes cancellation of a pesticide regis-
tration if unreasonable adverse effects
to the environment and  public health
develop when a product is used accord-
ing to widespread and commonly recog-
nized practice, or if  its labeling or
other material required to be  submit-
ted does not comply with  FIFRA provi-
sions.
Cap: A layer of clay, or other imperme-
able material installed over the top of
a closed  landfill to prevent entry  of
rainwater and minimize  leachate.
Capacity Assurance Flan: A statewide
plan which supports a state's ability to
manage the hazardous waste generat-
ed within its boundaries over a twenty
year period.
Capillary Action: Movement of water
through very small spaces to to molec-
ular forces called capillary forces.
Capillary Fringe: The porous  matrial
just above the water table which may
hold water by capillarity (a property of
surface tension that draws water up-
wards) in the smaller void spaces.
Capture  Efficiency: The fraction of
organic vapors generated by a process
that is directed to an abatement or re-
covery device.
Carbon Absorber An add-on  control
device that uses activated carbon to
absorb volatile  organic compounds
from a gas stream.  (The VOCs are
later recovered from the carbon.)
Carbon Adsorption: A treatment sys-
tem that removes contaminants from
ground water or surface water by forc-
ing it through tanks  containing acti-
vated carbon treated to attract the con-
taminants.
Carbon  Monoxide (CO): A colorless,
odorless,  poisonous gas  produced by
incomplete fossil fuel  combustion.
Carboxyhemoglobin:  Hemoglobin  in
which the iron  is bound to  carbon
monoxide (CO) instead of oxygen.
Carcinogen: Any substance that can
cause or aggravate cancer.
Carrier The inert liquid or solid mate-
rial added to an active ingredient in a
pesticide.
Carrying Capacity:  1. In recreation
management,  the  amount  of use  a
recreation area  can  sustain  without
loss of quality. 2. In wildlife manage-
ment, the Tnn-rimiiTn  number of ani-
mals  an area can support during a
given period.

CAS Registration Number A  number
asigned by the Chemical Abstract Ser-
vice to identify a chemical.

Cask: A thick-walled container (usually
lead)  used  to  transport radioactive
material. Also called a coffin.

Catalyst: A substance that changes the
speed or yield of a chemical reaction
without being consumed or chemically
changed by the chemical reaction.

Catalytic Converter.  An air pollution
abatement device that removes pollut-
ants from motor vehicle exhaust, either
by oxidizing them into carbon dioxide
and water or reducing them to nitro-
gen and oxygen.

Catalytic Incinerator A control device
that  oxidizes  volatile  organic  com-
pounds (VOCs) by using a catalyst to
promote the combustion process. Cata-
lytic incinerators require lower temper-
atures than conventional thermal in-
cinerators, thus saving fuel and other
costs.

Categorical Exclusion: A class of ac-
tions  which either individually or cu-
mulatively would not have a signifi-
cant effect on the human environment
and therefore would not require prepa-
ration of an environmental assessment
or  environmental impact statement
under the National Environmental
Policy Act (NEPA).
Categorical Pretreatment Standard: A
technology-based effluent limitation for
an industrial facility  discharging into
a municipal sewer system. Analogous
in stringency to Best Availability Tech-
nology (BAT) for direct dischargers.
Cathodic Protection:  A technique to
prevent corrosion of a metal surface by
making it the cathode  of an  electro-
chemical cell.
Cavitation: The formation and collapse
of gas pockets or bubbles on the blade
of an impeller or the gate of a' valve;
collapse of these pockets or bubbles
drives water with such force that it
can cause pitting of the  gate or valve
surface.
Cells: 1. In solid waste disposal, holes
where waste is  dumped, compacted,
and covered with layers of dirt on a
daily basis. 2. The smallest structural
part of living matter capable of func-
tioning as an independent unit.

Cementitious:  Densely  packed  and
nonfibrous friable materials.

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Central Collection Point: Location were
a generator of regulated medical waste
consolidates wastes originally generat-
ed at various locations in his facility.
The  wastes  are gathered together for
treatment on-site or for transportation
elsewhere for treatment and/or dispos-
al. This term could also apply to com-
munity hazardous waste collections, in-
dustrial and other waste management
systems.

Centrifugal  Collector  A mechanical
system using centrifugal force to re-
move aerosols from a gas stream or to
de-water sludge.
Channelization:  Straightening  and
deepening streams so water will move
faster, a marsh-drainage tactic  that
can-interfere with  waste assimilation
capacity, disturb fish and wildlife habi-
tats, and aggravate flooding.
Characteristic:  Any one  of the  four
categories used in  defining hazardous
waste: ignitability, corrosivity, reactivi-
ty, and toxicity.
Chemical Oxygen  Demand (COD): A
measure of the oxygen  required  to
oxidize  all compounds, both organic
and inorganic, in water.

Chemical Treatment:  Any one of a
variety of technologies that use chemi-
cals or a variety of chemical processes
to treat waste.
Chemnet: Mutual aid network of chem-
ical shippers and contractors that as-
signs a contracted emergency response
company to provide technical support
if a representative of the firm whose
chemicals are involved in an incident
is not readily available.
Chemoeterilant: A  chemical  that con-
trols pests by preventing reproduction.
Chemtrec:   The   industry-sponsored
Chemical Transportation Emergency
Center; provides information  and/or
emergency assistance  to emergency
responders.
Chilling  Effect The lowering of the
Earth's temperature  because of in-
creased particles in the  air blocking
the sun's rays.   (See: greenhouse ef-
fect.)
Chisel Plowing: Preparing croplands by
using a special implement that avoids
complete inversion of .the soil as with
conventional plowing. Chisel plowing
can leave a protective cover or crops
residues  on the soil surface to help
prevent erosion  and improve filtration.
Chlorinated Hydrocarbons:  These in-
clude a class of persistent, broad-spec-
trum insecticides that linger  in the
environment  and accumulate  in the
food chain. Among them are DDT, al-
drin, dieldrin, heptachlor, chlordane,
lindane, endrin, mi rex, hexachloride,
and toxaphene.  Other examples  in-
clude TCE, used as  an industrial sol-
vent.
Chlorinated Solvent: An organic sol-
vent containing chlorine  atoms, e.g.,
methylene  chloride  and 1,1,1-trichlo-
romethane, used in aerosol spray con-
tainers and in highway paint.
Chlorination: The application of chlo-
rine to  drinking water,  sewage, or
industrial waste to disinfect or to oxi-
dize undesirable compounds.
Chlorinator A device  that 'adds chlo-
rine, in gas or liquid form, to water or
sewage to kill infectious bacteria.

Chlorine-Contact Chamber  That part
of a water treatment plant where efflu-
ent is disinfected by chlorine.
Chlorofluorocarbons (CFCs): A family
of inert, nontoxic, and easily liquified
chemicals used  in  refrigeration,  air
conditioning, packaging, insulation, or
as solvents and aerosol  propellants.
Because. CFCs are not destroyed in the
lower atmosphere they drift into the
upper atmosphere where their chlorine
components destroy  ozone.
Chlorophenoxy: A class of herbicides
that may be found in  domestic water
supplies  and  cause adverse   health
effects.
Chkntu: Discoloration of normally
green plant parts caused by disease,
lack of nutrients, or various  air pollut-
ants.

Cholineflterase: An  enzyme found in
animala that regulates nerve impulses.
Cholineaterase inhibition is associated
with a variety of acute symptoms such
as nausea, vomiting,  blurred  vision,
stomach cramps, and rapid heart rate.
Chromium: (See: heavy metals.)
Chronic Effect: An adverse effect on a
human or animal in which symptoms
recur frequently or develop slowly over
a long period of time.
Chrome Toxicity: The capacity of a
substance to cause long-term poisonous
human health effects. (See: acute toxic-
ity.)
Circle of Tnfln«m«a- The circular outer
edge of a deppression produced in the
water table by the pumping of water
from a well. (See: cone of depression.)

Cistern: Small tank or storage facility
used to store water for a home or farm;
often used to store rain water.

Clarification:  Clearing action  that
occurs during wastewater  treatment
when solids settle out. This  is often
aided by centrifugal action and chemi-
cally induced coagulation in  wastewat-
er.

Clarifier A tank in which solids settle
to the bottom and are subsequently re-
moved as sludge.

Class I Area: Under the Clean Air Act.
a Class I area is one in which visibility
is protected  more  stringently  than
under the national ambient  air quality
standards;  includes  national parks,
wilderness  areas, monuments,  and
other areas of special national and cul-
tural significance.

Clay  Soil:  Soil  material   containing
more than  40 percent clay, less  than
45 percent sand, and less than 40
percent silt.

Clean Coal Technology: Any technology
not in widespread use prior to the
Clean Air Act amendments of 1990.
This Act will achieve significant reduc-
tions in pollutants associated with the
burning of coal.

Clean Fuels: Blends or substitutes for
gasoline fuels,  including compressed
natural gas, methanol, ethanol, liqui-
fied petroleum gas, and others.

Cleanup: Actions taken to deal with a
release or threat of release of a haz-
ardous  substance  that could affect
humans and/or the environment. The
term "cleanup" is sometimes used in-
terchangeably with the terms remedial
action, removal action, response action,
or corrective action.

Clear Cut: Harvesting all the trees in
one area at one time, a practice that
can   encourage  fast  rainfall   or
snowmelt runoff, erosion, sedimenta-
tion of streams and lakes, flooding, and
destroys vital habitat.

Clear Well: A reservoir for  storing
filtered water of sufficient quantity to
prevent the need to vary the filtration
rate  with varatioins in demand. Also
used to provide chlorine contact time
for disinfection.

Cloning: In biotechnology, obtaining a
group of genetically identical cells from
a single cell; making identical copies of
a gene.

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8
Closed-Loop Recycling: Reclaiming or
reusing wastewater for  non-potable
purposes in an enclosed process.

Closure: The procedure a landfill oper-
ator must follow when a landfill reach-
es its legal capacity for solid  waste:
ceasing acceptance of solid waste and
placing a cap on the landfill site.

Coagulation: Clumping of particles in
wastewater to  settle  out impurities,
often  induced by chemicals such as
lime, alum, and iron salts.

Coal Cleaning Technology: Precombus-
tion process by which coal is physically
or chemically treated to remove some
of its sulfur  so as to reduce  sulfur
dioxide emissions.   .
Coal Gasification; Conversion of coal to
a gaseous product by one of several
available technologies.

Coastal Zone: Lands and waters adja-
cent to the coast that exert an influ-
ence on the uses of the  sea and its
ecology, or whose uses and ecology are
affected by the sea.

Coefficient of Haze (COH): A measure-
ment  of visibility interference  in the
atmosphere.

Co-fire: Burning of two fuels in the
same  combustion  unit, e.g., coal and
natural gas, or oil and coal.
Coke  Oven:  An  industrial process
which converts  coal into coke, one of
the basic materials used in blast fur-
naces for  the conversion of iron ore
into iron.

Gold Temperature CO: A standard for
automobile carbon  monoxide  (CO)
emissions to be met at a low tempera-
ture (i.e. 20 degrees Fahrenheit). Con-
ventional automobile catalytic conver-
ters are less efficient upon start-up at
low temperatures.

Colifonn Index: A rating of the purity
of water based on a count of fecal bac-
teria.
Colifonn   Organism:  Microorganism
found in the intestinal tract of humans •
and animals. Their presence in water
indicates fecal pollution and potentially
adverse contamination by pathogens.
Collector Sewers: Pipes used to collect
and carry wastewater from individual
sources to an interceptor sewer that
will carry it to a treatment facility.
Colloids:  Very  small, finely divided
solids (that do not dissolve) that re-
main dispersed in a liquid for a long
time due to their small size and electri-
cal charge.
Combined Sewer Overflow: Discharge
of a mixture of storm water and do-
mestic waste when the flow capacity of
a  sewer system is exceeded during
rainstorms.

Combined Sewers: A sewer system that
carries both sewage and storm-water
runoff. Normally, its entire flow goes to
a waste treatment plant, but during a
heavy storm, the volume of water may
be so great  as to cause overflows of
untreated mixtures of storm water and
sewage into receiving waters. Storm-
water  runoff may  also  carry  toxic
chemicals from  industrial  areas  or
streets into the sewer system.

Combustion: 1. Burning, or rapid oxi-
dation, accompanied by release of ener-
gy in the form of heat and light. A
basic cause of air pollution. 2. Refers to
controlled burning of waste, in which
heat chemically  alters  organic  com-
pounds, converting them into stable
inorganics such as carbon dioxide and
water.

Combustion Chamber The actual com-
partment where waste is burned in an
incinerator.

Combustion  Product: Substance pro-
duced during the burning or oxidation
of a material.

Command Poet:  Facility located at a
safe distance upwind from an accident
site, where the on-scene coordinator,
responders, and technical representa-
tives make response decisions, deploy
manpower and  equipment,  maintain
liaison with  news media,  and handle
communications.
Comment Period: Time provided for
the public to review and comment on a
proposed EPA action or  rulemaking
after publication in the Federal Regis-.
ter.
Commercial Waste Management Facil-
ity: A treatment, storage,  disposal, or
transfer facility which accepts waste
from a variety of sources, as compared
to a private facility which  normally
manages a limited waste stream gener-
ated by its own operations.
Commercial  Waste: All solid waste
emanating from business establish-
ments such as stores, markets, office
buildings, restaurants, shopping cen-
ters, and theaters.
Commingled Recyclables: Mixed recyc-
lables that are collected together.
Comminuter: A machine that shreds or
pulverizes solids to make waste treat-
ment easier.
Comminution: Mechanical shredding or
pulverizing of waste. Used in both solid
waste  management and wastewater
treatment.

Community:  In ecology, a group of
interacting populations  in time and
space.  Sometimes,  a  particular sub-
grouping may be specified, such as the
fish community in a lake or the soil
arthropod community in a forest.

Community Relations: The EPA effort
to establish tworway  communication
with  the public to  create  under-
standing of EPA programs and related
actions, to assure public input into
decision-making processes related to
affected  communities, and  to make
certain that the Agency is  aware of
and  responsive  to  public concerns.
Specific community relations activities
are required in relation  to Superfund
remedial actions.
Community Water System: A public
water system which  serves at least 15
service connections used by year-round
residents or regularly serves at least
25 year-round residents.

Compaction: Reduction of the  bulk of
solid waste by rolling and tamping.

Complete Treatment: A method of
treating  water  that consists  of the
addition of coagulant chemicals, flash
mixing, coagulation-flocculation, sedi-
mentation, and filtration. Also called
conventional filtration.
Compliance Coal  Any coal tht emits
less than 1.2 pounds of sulfur  dioxide
per million Btu when burned. Also
known as low sulfur coal.
Compliance Coating: A coating whose
volatile organic compound content does
not exceed that allowed by regulation.
Compliance Cycle: The 9-year calendar
year cycle, beginning January 1,1993,
during which public  water systems
must monitor. Each cycle consists of
three 3-year compliance periods.
Compliance Monitoring: Collection and
evaluation of data, including self-moni-
toring reports, and verification to show
whether pollutant concentrations and
loads contained in permitted discharg-
es are in compliance with the limits
and conditions specified in the  permit.
Compliance  Schedule:  A negotiated
agreement between a pollution source
and a government agency that specifies
dates  and procedures  by  which  a
source will  reduce  emissions  and,
thereby, comply with a regulation.

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                                                                                                             9
 Composite Sample: A series of water
 samples taken over a given period of
 time and weighted by flow rate.

 Comport: The relatively stable humus
 material that is produced from a comp-
 osting process in which bacteria in soil
 mixed with  garbage  and degradable
 trash break down the mixture into or-
 ganic fertilizer.

 Composting: The controlled biological
 decomposition  of organic material  in
 the presence of air to form  a humus-
 like material.  Controlled methods  of
 composting include mechanical mixing
 and aerating, ventilating the materials
 by dropping them through  a vertical
 series of aerated chambers, or placing
 the compost in piles out in the open air
 and mixing it or turning it periodically.

 Compressed Natural  Gaa (CNG): An
 alternative fuel  for  motor  vehicles;
 considered one of the cleanest because
 of low hydrocarbon emissions and its
 vapors are relatively non-ozone produc-
 ing. It does, however, emit a signifi-
 cant quantity of nitrogen oxides.

 Conditional Registration: Under special
 circumstances, the Federal Insecticide,
 Fungicide,   and   Rodenticide   Act
 (FIFRA) permits registration of pesti-
 cide products that is "conditional" upon
 the submission  of additional data.
 These special circumstances include-a
. finding by the EPA Administrator that
 a new product or use of an existing
 pesticide will not significantly increase
 the risk of unreasonable adverse ef-
 fects. A product-containing a new (pre-
 viously unregistered) active ingredient
 may be conditionally registered only if
 the Administrator finds that  such
 conditional registration is in the public
 interest, that a reasonable  time for
 conducting the additional studies has
 not elapsed, and the use of the pesti-
 cide for the period of conditional regis-
 tration will not present an unreason-
 able risk.

 Conditionally Exempt Generators (CE):
 Persons or enterprises which produce
 less than  220 pounds  of hazardous
 waste per  month. Exempt from most
 regulation, they are required merely to
 determine whether their waste is haz-
 ardous,  notify appropriate   state  or
 local agencies, and ship it by permitted
 facility for proper disposal. (See: small
 quantity generator.)
 Conductance: A rapid method of esti-
 mating the dissolved solids content of
 water supply by determining the ca-
 pacity of a water sample to carry an
 electrical current.
Conductivity: A measure of the ability
of a solution to carry and electrical
curerent.
Cone of Depression: A depression in
the water table that develops around a
pumped well.
Cone  of
                   The depression,.
                                  .
roughly conical in shape, produced in a
water table by the pumping of a well.

Confined Aquifer An aquifer in which
ground water is confined under pres-
sure which is significantly greater than
atmospheric pressure.

Confluent Growth: A continuous bacte-
rial growth covering all or part of the
filtration area of a membrane filter in
which the bacteria colonies are not
discrete.

Consent Decree: A legal document, ap-
proved by a  judge,  that formalizes an
agreement reached between EPA and
potentially responsible parties (PRPs)
through which PRPs will conduct all or
part of a cleanup action at a Superfund
site; cease or correct actions or pro-
cesses that are  polluting the environ-
ment; or otherwise comply with EPA
initiated  regulatory  enforcement  ac-
tions to resolve the contamination  at
the Superfund site involved.  The con-
sent decree describes the actions PRPs
will take and may be  subject to a pub-
lic comment  period.

Conservation: Preserving and renew-
ing, when possible, human and natural
resources. The  use,  protection,  and
improvement of natural resources ac-
cording to principles  that will assure
their highest economic or social bene-
fits.

Construction and Demolition Waste:
Waste  building materials,  dredging
materials, tree stumps,  and rubble
resulting from construction,  remodel-
ing, repair, and demolition of homes,
commercial buildings and other struc-
tures  and pavements.  May contain
lead, asbestos, or other hazardous sub-
stances.

Construction Ban: If,  under the Clean
Air Act,  EPA  disapproves an area's
planning requirements  for correcting
nonattainment,  EPA can ban the con-
struction or modification of any major
stationery source of the pollutant for
which the area is in nonattainment.

Consumptive Water  Use: Water  re-
moved from available supplies without
return to a  water resources system,
e.g., water  used in manufacturing,
agriculture, and food  preparation.
Contact Pesticide: A chemical that kills
pests when it touches them, instead of
by ingestion. Also, soil that contains
the minute skeletons of certain algae
that scratch and dehydrate waxy coat-
ed insects.

Contaminant: Any physical, chemical,
biological, or radiological substance or
matter that has an adverse affect on
air, water, or soil.

Contamination: Introduction into wa-
ter,  air,  and soil of microorganisms,
chemicals, toxic substances, wastes, or
waste water in a concentration that
makes the medium unfit for its next
intended use. Also applies to surfaces
of  objects,  buildings, and  various
household and agricultural use prod-
ucts.

Contingency Plan: A document setting
out an organized, planned, and coordi-
nated course of action to be followed in
case of a fire, explosion, or other acci-
dent that  releases toxic chemicals,
hazardous waste, or radioactive mate-
rials that threaten human health  or
the environment. (See: National Oil
and Hazardous Substances Contingen-
cy Plan.)

Continuous  Discharge: A routine re-
lease to the environment that occurs
without interruption, except for  infre-
quent  shutdowns  for maintenance,
process changes, etc.

Continuous  Sample: A flow of water
from a particular place in a plant  to
the location where  samples are col-
lected for testing. May be used to ob-
tain grab or composite samples.

Contour  Plowing: Soil tilling method
that follows the shape of the land to
discourage erosion.

Contour Strip Farming: A kind of con-
tour farming in which row crops are
planted in strips, between alternating
stripls of close-growing, erosion-resis-
tant forage crops.

Contract Labs:  Laboratories  under
contract to EPA, which analyze sam-
ples taken from waste, soil, air, and
water or carry out research projects.

Control Technique Guidelines (CTG): A
series of EPA documents designed  to
assist states in defining  reasonable
available control technology (RACT) for
major sources of volatile organic com-
pounds (VOC).
Controlled Reaction: A chemical reac-
tion under temperature and pressure
conditions  maintained  within  safe

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 10
 limits to produce a desired product or
 process.

 Conventional Filtration: (See: complete
 treatment.)

 Conventional  Pollutants: Statutorily
 listed pollutants understood well by
 scientists. These may be in the form of
 organic waste, sediment, acid, bacteria,
 viruses, nutrients, oil  and grease, or
 heat.

 Conventional  Systems: Systems that
 have been traditionally used to collect
 municipal wastewater  in gravity sew-
 ers and convey it to a central primary
 or secondary treatment plant prior to
 discharge to surface waters.

 Conventional  Tilling:  Tillage opera-
 tions considered standard for a specific
 location and crop and that tend to bury
 the crop  residues; usually considered
 as  a base for determining the cost
 effectiveness of control  practices.

 Conveyance Loss: Water loss in pipes,
 channels, conduits, ditches by leakage
 or evaporation.

 Cooling Electricity Use:  Amount of
 electricity used to meet the building
 cooling load.  (See: building  cooling
 load.)

 Cooling Tower A structure that helps
 remove heat from water used as a cool-
 ant; e.g.,  in electric power generating
 plants.
 Cooperative Agreement: An assistance
 agreement  whereby EPA transfers
money, property,  services or anything
of value to  a state for the accomplish-
ment of CERCLA-authorized activities
or tasks.
Core: The uranium-containing heart of
a nuclear reactor, where energy is re-
leased.             ;
Core Program Cooperative Agreement:
An assistance agreement whereby EPA
 supports  states or tribal governments
with funds to help defray the cost of
non-item-specific  administrative and
training activities.
 Corrosion: The dissolution and wearing
 away of metal caused  by a rhamirjl
 reaction such as between water and
 the pipes, chemicals touching a metal
 surface, or contact between two metals.
Corrosive: A chemical agent that reacts
with the surface of a material causing
 it to deteriorate or wear away.
 CoaVBenefit Analysis:  A quantitative
 evaluation of the costs which would be
 incurred by implementing an environ-
 mental regulation versus the overall
benefits to society of the proposed action.

Cost-Effective Alternative: An alterna-
tive control or corrective method iden-
tified after analysis as  being the best
available in terms of reliability, perfor-
mance,  and cost. Although costs are
one important consideration, regulat-
ory and compliance analysis does not
require EPA to choose the least expen-
sive alternative. For example, when
selecting or approving a method for
cleaning up a Superfund site the Agen-
cy balances  costs with the long-term
effectiveness of the methods proposed
and the  potenetial danger posed by the
site.

Cost  Recovery:  A  legal  process by
which potentially responsible parties
who contributed to contamination at a
Superfund site can be required to re-
imburse  the  Trust Fund for  money
spent during any cleanup actions by
the federal government.

Cost Sharing: A publicly financed pro-
gram through which society, as a bene-
ficiary of environmental  protection,
shares part of  the cost  of pollution
control with those who must actually
install the controls. In Superfund, for
example, the government may pay part
of the cost.of a cleanup action with
those responsible  for  the pollution
paying the major share.
Cover Crop: A crop that provides tem-
porary protection for delicate seedlings
and/or provides a cover  canopy for
seasonal soil protection and improve-
ment between normal crop production
periods.
Cover Material: Soil used to cover com-
pacted solid waste in a sanitary land-
fill.         .
Cradle-to-Grave or Manifest System: A
procedure in which hazardous materi-
als are identified and followed as they
are produced, treated, transported, and
disposed of by a series of permanent,
linkable, descriptive documents (e.g.,
manifests). Commonly  referred to as
the cradle-to-grave system.

Criteria Pollutants:  The 1970 amend-
ments to the Clean Air Act required
EPA to set National Ambient Air Qual-
ity Standards for certain pollutants
known  to be hazardous to  human
health.  EPA has identified and set
standards to protect human health and
welfare  for six pollutants: ozone, car-
bon monoxide, total suspended particu-
lates, sulfur dioxide, lead, and nitrogen
oxide. The term, "criteria pollutants"
derives from the requirement that EPA
must describe the characteristics and
potential health and welfare effects of
 these pollutants. It is on the basis of
 these criteria that standards are set or
 revised.

 Criteria: Descriptive factors taken into
 account by EPA in setting standards
 for various  pollutants.  These factors
 are used to determine limits on allow-
 able concentration levels, and to limit
 the  number of violations per year.
 When issued by EPA, the criteria pro-
 vide guidance to the states on how to
 establish their standards.

 Crop Consumptive Use: The amount of
 water transpired during plant growth
 plus  what evaporated  from  the  soil
 surface and foliage in the crop area.

 Crop Rotation: Planting a succession of
 different crops on the same land rea as
 opposed to planting the same crop time
 after time.

 Cross-Connection: Any actual or poten-
 tial  connection  between a drinking
 water systemm and  an  unapproved
 water supply  or other source of  con-'
 tamination.

 Cubic Feet Per Minute (CFM): A mea-
 sure of the volume of a substance flow-
 ing through air within a  fixed period of
 time. With regard to indoor air, refers
 to the amount of air, in cubic feet, that
 is exchanged  with indoor  air in a
 minute's time, i.e., the air exchange
 rate.  Also applies to liquid flows.

 Gullet: Crushed glass.

 Cultural  Eutropbication: Increasing
 rate at which water bodies "die" by pol-
 lution from human activities.

 Cultures and Stocks: Infectious agents
 and  associated biologicals including:
 cultures from medical and pathological
 laboratories; cultures and stocks  of
 infectious agents from  research  and
 industrial laboratories; waste from the
 production of biologicals; discarded live
 and  attenuated vaccines; and culture
 dishes and devices used to transfer, in-
'oculate, and mix cultures. (See: regu-
 lated medical waste.)

 Cumulative Exposure:  The  sum  of
 exposures of an organism to a pollut-
 ant over a period of time.

 Cumulative Working Level Months
 (CWLM): The sum of lifetime exposure
 to radon working levels expressed in
 total working level months.

 Curb Stop:  A water service  shutoff
 valve located in a water service  pipe
 near the curb and between the water
 main and the building.

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                                                                                                           11
 Curbside Collection: Method of collect-
 ing  recyclable materials at  homes,
 community districts or businesses.

 Cutie-Pie: An instrument used to mea-
 sure radiation levels.

 Cyclone  Collector. A device that uses
 centrifugal force to pull large particles
 from polluted air.
Data Call-In; A part of the Office of
Pesticide Programs (OPP) process of
developing  key required  test data,
especially on the  long-term, chronic
effects of ««riiiting pesticides, in ad-
vance of scheduled Registration Stan-
dard reviews. Data Call-In from man-
ufacturers is an adjunct of the Regis-
tration Standards program intended to
expedite re-registration.

Day Tank: (See: age tank)

DDT:  The  first  chlorinated
hydrocarboninsecticide r^Amiral name:
Dichloro-Diphenyl-Trichloroethane). It
has a half-life of 15 years and can col-
lect in fatty tissues of certain animals.
EPA banned registration  and inter-
state sale of DDT for virtually, all but
emergency uses in the United States in
1972 because of its persistence in the
environment and accumulation in the
food chain.

Dead End: The end  of a water main
which is not connected to other parts of
the distribution system.

Decant: To draw off the upper layer of
liquid after  the heaviet material (a
solid or another liquid) has settled.

Decay Products: Degraded radioactive
materials, often referred to as "daugh-
ters" or "progeny"; radon decay prod-
ucts of most concern from a public
health standpoint are polonium-214
and  polonium-218.

Dechlorination: Removal  of chlorine
from a substance by chemically replac-
ing it with hydrogen or hydroxide ions
in order to detoxify a substances.

Decomposition:   The  breakdown of
matter by bacteria and fungi, changing
the chemical makeup and physical ap-
pearance of materials.

Decontamination: Removal of harmful
substances such as noxious I'hftTnirala,
.harmful bacteria or  other organisms,
or radioactive material from exposed
individuals, rooms and furnishings in
buildings, or the exterior environment.
Deep-Well Injection: Deposition of raw
or treated, filtered hazardous waste by
pumping it into deep wells, where it is
contained in the pores of permeable
subsurface rock.

Deflocculating Agent A material added
to a suspension to prevent settling.

Defhioridation:  The removal of excess
Qouride in drinking water to prevent
the staining of teeth.

Defoliant: An herbicide that removes
leaves from trees and growing- plants.

Degaaification: A water    treatment
that removes    dissolved gases from
the water.

Delegated State:  A state  (or other
governmental entity such as a tribal
government) that has received authori-
ty to administer  an environmental
regulatory program in lieu of a federal
counterpart  As used in connection
with NPDES,  UIC,  and PWS  pro-
grams, the term does not connote any
transfer of federal authority to a state.

Delist Use of the  petition process to
have a facility's toxic designation re-
scinded.
Demand-aide  Waste  Management:
Prices  whereby consumers use pur-
chasing decisions to communicate to
product manufacturers that they prefer
environmentally sound products pack-
aged with the least amount of waste,
made from recycled or recyclable mate-
rials,  »T»ti  containing no hazardous
substances.
rwrmfn«»r«ii«ntinTv A treatment process
that removes dissolved minerals from
water.
Denitrification:  The anaerobic biolog-
ical reduction of nitrate to nitrogen
gas.
Density:  A measure of how heavy a
solid, liquid, or  gas is for its size.

Depletion Curve:  In hydraulics, a
graphical representation of water de-
pletion from storage-stream channels,
surface soil, and groundwater. A deple-
tion curve can be drawn for base flow,
direct runoff, or total flow.

Depressurization:  A  condition that
occurs when the air pressure inside a
structure is lower that the air pressure
outside.  Depressurization can occur
when household appliances such  as
fireplaces or furnaces,  that consume or
exhaust  house  air, are  not supplied
with enough makeup  air. Radon may
be drawn into  a house more rapidly
under depressurized conditions.
Dermal Exposure: Contact between a
chemical and the akin.

Dermal Toxicity: The ability of a pesti-
cide or toxic chemical to poison people
or animals by contact with the skin.
(See: contact pesticide.)

DBS: A synthetic estrogen, diethylstil-
bestrol is used as a growth stimulant
in food animals. Residues in meat are
thought to be carcinogenic.

Desalination: [Desalinization] (1) Re-
moving salts from ocean or brackish
water by using various technologies.
(2) Removal of salts from soil by artifi-
cial means, usually leaching.

Deaiccant A chemical agent that ab-
sorbs moisture; some desiccants are
capable of drying out plants or insects,
causing death.

Design  Capacity: The  average daily
flow that a treatment plant or other
facility is designed to accommodate.

Design Value: The monitored reading
used by EPA to determine an area's air
quality  status, e.g., for  ozone,  the
fourth highest reading measured over
the most recent  three  years is the
design value.

Designated Pollutant An air pollutant
which is neither a criteria nor hazard-
ous  pollutant,  as described  in  the
Clean  Air  Act, but for which  new
source performance  standards  exist.
The Clean Air Act does require states
to control these pollutants, which in-
clude acid mist, total reduced sulfur
(TRS), and fluorides.

Designated  Uses: Those water  uses
identified in state water quality stan-
dards that must be achieved and main-
tained as required  under the Clean
Water Act Uses can include cold water
fisheries, public water  supply, irriga-
tion, etc.

Designer Bugs: Popular term for mi-
crobes developed through biotechnology
that can degrade specific toxic chemi-
cals at their source in toxic waste
dumps or in ground water.

Destination Facility: The facility to
which  regulated  medical  waste  is
shipped for treatment and destruction,
incineration, and/or disposal.
 WaiLi iitjr^^jnm- Vertical mnring within
a lake or reservoir to totally or partial-
ly eliminate separate layers of temper-
ature, plant, or animal life.

Destroyed Medical  Waste: Regulated
medical waste that has been ruined,
torn apart, or mutilated through ther-

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12
mal treatment, melting,  shredding,
grinding, tearing, or breaking, so that
it is no longer generally recognized as
medical waste, but has not yet been
treated (excludes compacted regulated
medical waste.)

Destruction and Removal Efficiency
(DRE): A percentage  that represents
the  number of  molecules of  a com-
pound removed or destroyed  in  an
incinerator relative to the number of
molecules that  entered the •  system
(e.g., a DRE of  99.99 percent means
that 9,999 molecules are destroyed for
every 10,000 that enter; 99.99 percent
is known as "four nines." For some
pollutants, the RCRA removal require-
ment  may  be  a  stringent  as  "six
nines.")
Destruction Facility: A facility that de-
stroys  regulated medical waste  by
mashing or mutilating it.

Detention Time:  1. The theoretical cal-
culated time  required for a  small
amount of water to  pass through a
tank at a given rate  of flow.  2. The
actual  time that a small  amount of
water is in a settling  basin, flocculat-
ing basin, or rapid-mix chamber. 3. In
storage reservoirs, the length of time
water will be held before being used.

Desulfurization:  Removal of  sulfur
from fossil fuels  to reduce  pollution.

Detectable Leak Rate: The smallest
leak (from a storage tank), expressed
in terms of gallons-or liters-per-hour,
that a  test can reliably discern with a
certain probability of detection or false
alarm.
Detection Criterion: A predetermined
rule to ascertain whether a tank ia
leaking or not. Most volumetric testa
use a threshold value  as the detection
criterion. (See: volumetric tank testa.)
Detergent:  Synthetic  washing agent
that helps to remove dirt and oil. Some
contain compounds which kill useful
bacteria and encourage algae  growth
when  they  are  in wastewater that
reaches receiving waters.
Development Efifecta:  Adverse effects
such as  altered growth, structural
abnormality, functional deficiency, or
death observed in a developing organ-
ism.
Dewater  1.  Remove or  separate  a
portion of the water  in a sludge or
slurry  to dry the sludge so it «•-«" be
handled and disposed.    2.  Remove
or drain the water from a tank or
trench.
Diatomaceoua Earth (Diatomite): A
chalk-like material (fossilized diatoms)
used  to filter  out  -solid  waste  in
wastewater treatment plants; also used
as an active ingredient in some  pow-
dered pesticides.

Diazinon: An insecticide. In 1986, EPA
banned its use on open areas such as
sod farms and golf courses because it
posed a danger to migratory birds. The
ban  did not apply to  agricultural,
home lawn, or commercial establish-
ment uses.
         \
Dibenzofurans: A group of highly toxic
organic compounds.

Dicofol: A  pesticide used on citrus
fruits.

Diffused Air A type of aeration that
forces oxygen into sewage by pumping
air through perforated pipes inside a
holding tank.

Diffusion: The movement of suspended
or dissolved particles from a more con-
centrated to a less concentrated area.
The  process tends to distribute the
particles more uniformly.

Digester In wastewater treatment, a
closed tank; in solid-waste conversion,
a unit in which bacterial action is in-
duced  and  accelerated  in  order  to
break down organic matter and estab-
lish  the proper carbon  to  nitrogen
ratio.

Digestion: The biochemical decomposi-
tion  of organic  matter, resulting in
partial  gasification, liquefaction, and
mineralization of pollutants.
Dike: A low wall that can  act  as a
barrier to prevent a spill from spread-
ing.

Diluent: Any liquid or solid material
used to dilute or carry an active ingre-
dient

Dilution Ratio: The  relationship be-
tween the volume of water in a stream
and the volume of incoming water. It
affects  the ability of the stream to
assimilate waste.

Dimitie Lakes  and reservoirs  that
freeze over and  normally  go through
two  stratifications  and two mixing
cycles a year.
Dinocap: A fungicide used primarily by
apple growers to control summer dis-
eases. EPA proposed restrictions on its
use in  1986  when  laboratory  tests
found it caused birth defects in rabbits.

Dinoeeb: A herbicide that is  also used
as a fungicide and insecticide. It was
banned by EPA in  1986 because it
posed  the  risk of birth defects  and
sterility.

Dioxin: Any of a family of compounds
known chemically as dibenzo-p-dioxins.
Concern about them arises from their
potential toxicity and contaminants in
commercial products. Tests on labora-
tory animals indicate that it is one of
the more toxic man-made compounds.

Direct  Discharger A  municipal or
industrial  facility which  introduces
pollution through a defined conveyance
or system such as outlet pipes; a point
source.

Direct Filtration: A method of treating
water which consists of the addition of
coagulent  chemicals,  flash  mixing,
coagulation, minimal flocculation,  and
filtration. Sedimentation is not used!

Direct Runoff: Water  that  flows over
the  ground surface  or through  the
ground directly into streams, rivers,
and lakes.
Discharge:  Flow of surface  water-in a
stream or  canal or  the  outflow of
ground water from a flowing artisian
well, ditch,  or spring. Can also apply to
discharge of liquid effluent from a
facility  or to chemical  emissions  into
the  air through  designated venting
mechanisms.
Din
mfc A chemical or physical
process that kills pathogenic organisms
in water. Chlorine is often  used to
disinfect sewage  treatment effluent,
water supplies, wells, and swimming
pools.
Disinfectant By-Producfc A compound
formed  by   the  reaction  of   a
disinfenctant such as chlorine with or-
ganic material in the water supply.

Disinfectant Time: The time it takes
water to move from the point of disin-
fectant application (or the previous
point of residual disinfectant measure-
ment) to a point before or at the point
where the residual disinfectant is mea-
sured.
Dispersant: A chemical agent used to
break  up  concentrations  of organic
material such as spilled oil.
Disposables: Consumer products, other
items,  and packaging used once or a
few times and discarded.

Disposal: Final placement or destruc-
tion of toxic,  radioactive,  or  other
wastes; surplus or banned pesticides or
other chemicals;  polluted soils;  and
drums containing hazardous materials
from  removal  actions  or  accidental
releases.  Disposal may  be accom-
plished through use of approved secure

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                                                                                                           13
 landfills, surface impoundments, land
 farming, deep-well injection, ocean du-
 mping, or incineration.

 Dissolved Oxygen (DO): The  oxygen
 freely  available in water, vital to fish
 and other aquatic life and for the pre-
 vention of odors. DO levels are consid-
 ered a most important indicator of a
 water  body's ability to support desir-
 able aquatic life. Secondary  and ad-
 vanced waste treatment are generally
 designed to ensure  adequate DO in
 waste-receiving waters.

 Dissolved Solids: Disintegrated organic
 and inorganic material in water.  Ex-
 cessive amounts make water unfit to
 drink or use in industrial processes.

 Distillation: The  act of purifying li-
 quids  through boiling, so that the
 steam  condenses to a pure liquid and
 the pollutants remain in a concentrat-
 ed residue.

 Diversion: 1. Use of part of a stream
 flow as water supply. 2. A  channel
 with a supporting ridge on the lower
 side constructed across a slope to di-
 vert waster at a non-erosive velocity to
 sites where  ait can be used, and dis-
 posed of.

 Diversion Rate:  The  percentage  of
 waste  materials diverted from tradi-
 tional  disposal such as  landfilling or
 incineration to be recycled, composted,
 or re-used.

 DNA Hybridization: Use of a segment
 of DNA, called a DNA probe, to identi-
 fy its  complementary DNA;  used to
 detect specific genes.

 Dosage/Dose: The actual quantity of a
 chemical administered to an organism
 or to which it is exposed.

 Doee Equivalent: The product of the
 absorbed dose from ionizing radiation
 and such factors as account for biologi-
 cal differences due to the type of radia-
 tion and its distribution in the body as
 specified by the International Commis-
 sion on Radiological Units and Mea-
 surements.

 Dose Response: How a biological orga-
 nism's  response to  a toxic substance
 quantitatively shifts as its   overall
exposure to  the  substance: changes
(e.g., a small dose of carbon monoxide
may cause drowsiness; a large dose can
be fatal.)

 Dose-Response Assessment Estimating
 the  potency of a chemical.

 Dose-Response Relationship: The quan-
 titative  relationship  between  the
amount of exposure to a substance and
the extent of toxic  injury or disease
produced.

DOT Reportable Quantity: The quanti-
ty of a substance specified in U.S. De-
partment of Transportation regulation
that triggers  labelling, packaging and
other requirements related to shipping
such substances.

Downgradient   The  diretion  that
groundwater  flows;  similar to "down-
stream" for surface water.

Draft  1. The  act of drawing or remov-
ing water from  a tank or reservoir. 2.
The water which is drawn or removed.

Draft  Permit: A  preliminary permit
drafted and published by EPA; subject
to public review and comment before
final action on  the application.

Drainage: Improving the productivity
of agricultural land by removing excess
water from the  soil by such means  as
ditches or subsurface drainage tiles.

Drainage Basin: The area of land that
drains water, sediment,  and dissolved
materials to a common outlet at some
point along a stream channel.

Drainage Well:  A well drilled to carry
excess water off agricultural fieleds.
Because they act as  a funnel from the
surface to the  groundwater below,
drainage  wells can  contribute   to
groundwater pollution.

Drawdown: 1. The drop in  the water
table or level of water in the ground
when water is being pumped from a
well. 2. The amount of water used from
a tank or reservoir. 3. The drop in the
water level of a tank or reservoir.

Dredging: Removal  of mud from the
bottom of water bodies.  This can dis-
turb the ecosystem  and cause silting
that kills aquatic life.  Dredging  of
contaminated muds can expose biota to
heavy metals and other toxics. Dredg-
ing activities may be subject to regula-
tion under Section 404  of the Clean
Water  Act

Drinking  Water  Equivalent  Level:
Protective level  of exposure  related to
potentially non-carcinogenc effects  of
chemicals that are also known to cause
cancer.

Drop-off: Recyclable materials  collec-
tion method in which individuals bring
them to a designated collection site.

Dump: A site used to dispose of solid
waste without environmental controls.
Dustfall Jar: An open container used to
collect large particles from the air for
measurement and analysis.

Dystrophic Lakes: Acidic, shallow bod-
ies of water that contain much humus
and/or other organic matter; contain
many plants but few fish.
Ecological Impact The effect  that a
man-made or natural activity  has on
living organisms and their non-living
(abiotic) environment.
Ecology:  The  relationship of living
things to one another and their envi-
ronment, or the study of such relation-
ships.

Ecological Indicator  A characteristic
of the environment that, when mea-
sured, quantifies magnitude of stress,
habitat characteristics, degree of expo-
sure to a stressor, or ecological re-
sponse to exposure.   The term is a
collective term for response, exposure,
habitat, and stressor indicators.

Ecological Risk Assessment  The ap-
plication of a formal  framework, ana-
lytical process, or  model to  estimate
the effects of human actions(s) on a
natural resource and to interpret the
significance of those effects in light of
the uncertainties  identified in each
component of the assessment process.
Such analysis  includes initial hazard
identification,  exposure and dose-re-
sponse assessments, and risk char-
acterization.

Rfmnnmic Poisons:  Chemicals used to
control pests  and to  defoliate cash
crops such as cotton.

Ecosphere: The "bio-bubble" that con-
tains life on earth, in surface waters,
and in the air. (See: biosphere.)

Ecosystem: The interacting system of a
biological community and its non-living
environmental surroundings.

Ecosystem Structure: Attributes relat-
ed to  instantaneous physical state of
an ecosystem; examples include species
population density, species richness or
evenness, and standing crop biomass.
      \
Ecotone: A habitat  created by the jux-
taposition of distinctly different habi-
tats; an edge habitat; or an ecological
zone or boundary where two or more
ecosystems meet.

Effluent  Wastewater,  treated   or
untreated that flows out of a treatment
plant,  sewer,   or  industrial  outfall.

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 14
 Generally refers to wastes discharged
 into surface waters.
 Effluent  Guidelines: Technical EPA
 documents which set effluent limita-
 tions for  given industries and pollut-
 ants.
 Effluent Limitation: Restrictions estab-
 lished by  a state or EPA on quantities,
 rates,   and   concentrations-  in
 wastewater discharges.
 Effluent Standard: (See: effluent limi-
 tation.)
 Ejector A device  used to disperse a
 chemical  solution  into  water being
 treated.            •
 Electrodialyais:  A  process that uses
 electrical  current applied to permeable
 membranes to remove minerals from
 water. Often used to desalinate salty
 or brackish water.
 Electrostatic  Precipitator (ESP):  A
 device that removes particles from a
 gas stream (smoke) after combustion
 occurs. The ESP imparts an electrical
 charge to the particles, causing them
 to adhere to metal plates inside the
 precipitator.  Rapping on the  plates
 causes the particles to fall into a hop-
 per for disposal.
 Eligible Costa: The construction costs
' for waste-water treatment works upon
 which EPA grants are based.
 EMAP Data: 'Environmental monitor-
 ing data collected under the auspices of
 the  Environmental Monitoring,  and
 Assessment Program. All EMAP data
 share the  common attribute of being of
 known quality, having been collected
 in the context of explicit data quality
 objectives (DQOs) and a consistent
 quality assurance program.
 Emergency  (Chemical):  A  situation
 created by  an accidental  release or
 spill of hazardous chemicals that poses
 a threat to the safety of workers, resi-
 dents, the environment, or property.
 Emergency Episode: (See: air pollution
 episode.)
 Emergency Response Values: Concen-
 trations  of chemicals,  published, by
 various groups,  defining  acceptable
 levels  for short-term  exposures in
 emergencies.
 Emission: Pollution discharged into the
 atmosphere from  smokestacks, other
 vents, and surface areas of commercial
 or industrial facilities; from residential
 chimneys; and from motor vehicle, loco-
 motive, or aircraft exhausts.
 Emission Cap:  A  limit designed to
 prevent projected growth in emissions
from  existing and  future stationary
sources from eroding any mandated re-
ductions.  Generally, such provisions
require any  emission  growth from
facilities  under the  restrictions be
offset by equivalent reductions at other
facilities under  the  saine cap. (See:
emissions trading)

Emission  Factor  The  relationship
between the amount of pollution pro-
duced and the amount of raw material
processed.  For example, an  emission
factor for a blast furnace making iron
would be the number of pounds of
particulates per ton of raw materials.

Emission  Inventory:  A listing,  by
source, of the amount of air pollutants
discharged into the atmosphere of  a
community; used to establish emission
standards.
Emission  Standard: The maximum
amount of air polluting discharge le-
gally  allowed from a  single source,
mobile or stationary.

Emissions Trading: The creation of
surplus emission reductions at certain
stacks,  vents or  similar emissions
sources and the use of this surplus to
meet  or redefine  pollution  require-
ments applicable to  other emissions
sources. This allows  one source  to
increase   emissions  when   another
source reduces them, maintaining an
overall constant emission level. Facili-
ties that reduce emissions substantial-
ly may "bank" their "credits" or sell
them  to other facilities or industries.
Encapsulation: The treatment of asbes-
tos-containing material with a liquid
that covers the surface with  a protec-
tive coating or embeds fibers in an
adhesive matrix to  prevent  their re-
lease  into the air.
Enclosure: Putting an airtight, imper-
meable, permanent barrier around as-
bestos-containing materials to prevent
the release of asbestos  fibers into the
air.
Endangered Species: Animals, birds,
fish, plants, or other living organisms
threatened with extinction  by  man-
made or natural changes in their envi-
ronment. Requirements for declaring a
species endangered are contained in
the Endangered Species Act.

Endangerment Assessment: A study to
determine the nature  and extent of
contamination at a site on the National
Priorities Last and the  risks  posed to
public health  or the environment. EPA
or the state conduct the study when a
legal  action is to be taken  to direct
potentially responsible parties to clean
up a site or pay for it. An endanger-
ment assessment supplements a reme-
dial investigation.

Endrin: A pesticide toxic to freshwater
and marine aquatic life that produces
adverse health  effects  in  domestic
water supplies..

Energy Recovery:  Obtaining  energy
from waste through a variety  of pro-
cesses (e.g., combustion.)

Enforceable Requirements: Conditions
or limitations in permits issued under
the Clean Water Act .Section  402 or
404  that,  if violated, could result in
the issuance of a compliance order or
initiation of a  civil or criminal action
under federal or applicable state laws.
If a permit has not been  issued,  the
term includes any requirement which,
in the Regional Administrator's judg-
ement, would be included in the permit
when issued. Where no permit applies,
the term  includes  any requirement
which the RA determines is necessary
for the best practical waste treatment
technology to meet applicable criteria.

Enforcement: EPA, state, or local legal
actions to obtain compliance with envi-
ronmental laws, rules, regulations, or
agreements and/or obtain penalties or
criminal sanctions for violations. En-
forcement procedures may vary,  de-
pending on the requirements of differ-
ent environmental  laws and related
implementing   regulations.   Under
CERCLA, for example, EPA will seek
to require potentially responsible par-
ties to clean up a  Superfund site, or
pay for the cleanup, whereas under the
Clean Air Act  the agency may  invoke
sanctions against cities failing to meet
ambient air quality standards  that
could prevent certain types of construc-
tion or federal  funding. In other situa-
tions, if investigations  by EPA and
state agencies uncover  willful viola-
tions, criminal trials and penalties are
sought.
Enforcement   Decision  Document
(EDD):  A document that provides  an
explanation to the public of EPA's se-
lection of the  cleanup  alternative at
enforcement sites  on  the  National
Priorities List.  Similar to a Record of
Decision.
Enhanced Inspection and Maintenance
(I&M): An improved automobile inspec-
tion and maintenance program—aimed
at reducing automobile emissions—that
contains, at a minimum, more  vehicle
types and model years, tighter  inspec-
tion, and better management practices.
It may also include annual computer-
ized or centralized inspections, under-

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                                                                                                          15
the-hood inspection- for signs of tam-
pering with pollution  control equip-
ment, and increased repair waiver cost.
Enrichment: The addition of nutrients
(e.g.,  nitrogen,  phosphorus,  carbon
compounds) from sewage  effluent or
agricultural runoff to  surface water;
greatly increases the growth potential
for algae and other aquatic plants.

Entrain:  To trap  bubbles in water
either  mechanically through  turbu-
lence or chemically through a reaction.

Environment: The sum of all external
conditions affecting the life, develop-
ment and survival of an organism.

Environmental Assessment: An envi-
ronmental analysis prepared pursuant
to the National Environmental Policy
Act to determine whether a federal
action  would significantly  affect  the
environment and thus require a more
detailed environmental impact state-
ment.
Environmental Audit: An independent
assessment of  the current status of a
party's  compliance with  applicable
environmental requirements or of a
party's environmental compliance poli-
cies, practices,  and controls.

Environmental Equity/Justice: Equal
protection from environmental hazards
for individuals, groups, or communities
regardless of race, ethnicity, or eco-
nomic status. This applies to the  de-
velopment, implementation, and  en-
forcement of environmental laws, regu-
lations, and policies, and implies that
no  population  of "people  should be
forced to shoulder  a disproportionate
share of  negative environmental im-
pacts.
Environmental  Exposure:  Human
exposure to pollutants originating from
facility emissions. Threshold levels are
not necessarily surpassed, but low-
level chronic pollutant exposure is one
of the most common forma of environ-
mental exposure (See: threshold level).
Environmental Impact Statement: A
document required of federal agencies
by the National Environmental Policy
Act for major projects  or legislative
proposals significantly affecting the en-
vironment. A tool for decision making,
it describes the positive and negative
effects  of the  undertaking and cites
alternative actions.
Environmental Indicator: A measure-
ment, statistic or value that provides a
proximate gauge or  evidence  of the
effects of environmental management
programs or of the state or condition of
the environment.

Environmental Response Team: EPA
experts located in Edison, NJ,  and
Cincinnati,  OH,  who  can  provide
around-the-clock technical assistance
to EPA  regional offices and states
during all types of hazardous waste
site emergencies and spills of hazard-
ous substances.
Epidemiology: Study of the distribution
of disease,  or other  health-related
states  and events in human  popula-
tions, as related to age, sex,  occupa-
tion, ethnic,  and economic  status in
order to identify and alleviate health
problems and promote better health.
Epilimnion: Upper waters of a therm-
ally  stratified lake subject  to  wind
action.
Episode (Pollution): An air pollution
incident in a given area caused by a
concentration of atmospheric pollut-
ants under meteorological conditions
that may result in a significant  in-
crease in illnesses or deaths. May also
describe  water  pollution  events  or
hazardous material spills.
Equilibrium:  In relation to radiation,
the state at which the radioactivity of
consecutive elements within a radioac-
tive  series is neither increasing nor
decreasing.

Equivalent Method:  Any method of
sampling and analyzing for air pollu-
tion  which has been demonstrated to
the EPA Administrator's satisfaction to
be, under specific conditions, an  ac-
ceptable alternative to normally used
reference methods.

Erosion:  The wearing  away  of land
surface by wind or water, intensified
by land-clearing practices  related to
farming,  residential, or industrial de-
velopment, road building, or logging.
Estuary:  Regions of interaction be-
tween rivers and near-shore ocean wa-
ters, where tidal action and river flow
mi-r fresh and salt water. Such areas
include bays, mouths of rivers, salt
marshes, and lagoons. These brackish
water ecosystems shelter and feed ma-
rine  life, birds,  and wildlife.  (See:
wetlands.)

Ethanol:  An  altemativce automotive
fuel derived from grain and corn; usu-
ally  blended  with gasoline  to  form
gasohol.
Ethylene Dibromide (EDB): A chemical
used as an agricultural fumigant and
in certain  industrial  processes. Ex-
tremely toxic and found to be a car-
cinogen in laboratory animals, EDB
has been banned for most agricultural
uses in the United States.

Eutrophic Lakes: Shallow, murky bod-
ies of water with  concentrations  of
plant nutrients causing excessive pro-
duction  of  algae.  (See:  dystrophic
lakes.)

Eutrophication: The slow aging process
during which a lake, estuary,  or bay
evolves into a bog or marsh and even-
tually disappears. During  the later
stages of eutrophication the water body
is choked by abundant plant life due to
higher levels of  nutritive compounds
such  as  nitrogen  and phosphorus.
Human activities can accelerate the
process.

Evaporation Ponds:  Areas where sew-
age sludge is dumped and dried.

Evapotranapiration: The loss of water
from the soil both by evaporation and
by transpiration from the plants grow-
ing in the soil.

Exceedance: Violation of the pollutant
levels permitted by environmental pro-
tection standards.

Exclusion:  In  the asbestos program,
one of several situations that permit a
Local Education  Agency (LEA) to de-
lete one or more of the items required
by the Asbestos Hazard Emergency
Response Act (AHERA), e.g., records of
previous  asbestos  sample  collection
and analysis may be used by the ac-
credited  inspector in lieu of AHERA
bulk sampling.

Exclusionary Ordinance: Zoning that
excludes  classes of persons or busi-
nesses from a particular neighborhood
or area.

Exempt Solvent:  Specific organic com-
pounds not subject to requirements of
regulation because they are deemed by
EPA to be of negligible photochemical
reactivity.

Exempted Aquifer: Underground bod-
ies of water defined  in  the Under-
ground Injection Control  program as
aquifers that are potential  sources  of
drinking water though not being used
as such, and thus exempted from regu-
lations barring underground injection
activities.

Exemption: A state (with primacy) may
exempt a public water system  from-a
requirement involving an MCL, treat-
ment technique; or both, if the. system
cannot comply due to compelling eco-
nomic or other factors, or because the

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16
system was  in  operation before the
requirement  or  MCL was instituted,
and the exemption will  not create a
public health risk.

Exotic Species:  A species that is not
indigenous to a region.

Experimental Use Permit: Obtained by
manufacturers for testing new pesti-
cides or uses of thereof whenever they
conduct experimental field studies to
support  registration on  10 acres or
more on land or one acre or more of
water.

Explosive Limits: The amounts of va-
por in the air that form explosive mix-
tures;  limits  are expressed  as lower
and upper limits and give the range of
vapor concentrations in  air  that  \vill
explode if an ignition source is present.

Exposure: The amount of radiation or
pollutant present in a  given environ-
ment  that  represents  a  potential
health threat to  living organisms.

Exposure Assessment: Identifying the
pathways by  which  toxicants  may
reach  individuals,  estimating  how
much of a chemical an  individual is
likely to be exposed to, and estimating
the number likely to be exposed.

Exposure Indicator  A characteristic of
the environment measured to provide
evidence of the  occurrence or  magni-
tude of a response indicator's exposure
to a chemical or  biological stress.

Exposure Level:  The amount (concen-
tration) of a chemical at the absorptive
surfaces of an organism.

Extraction Procedure (E P Toxic): De-
termining toxicity by  a   procedure
which simulates leaching; if a  certain
concentration of  a toxic substance can
be leached from a waste, that waste is
considered hazardous, i.e., "E P Toxic."

Extremely  Hazardous  Substances:
Any of 406 chemicals identified by EPA
as toxic, and listed under SARA Title
III. The list is subject to periodic revi-
sion.
Fabric Filter: A cloth device that catch-
es dust particles from industrial emis-
sions.
Facilities  Plans: Plans  and studies
related to the  construction of  treat-
ment works necessary to comply with
the Clean Water Act or RCRA. A facili-
ties plan investigates needs and pro-
vides information on the cost effective-
ness of alternatives, a recommended
plan, an environmental assessment of
the recommendations, and descriptions
of the treatment works,  costs, and  a
completion schedule.

Facility Emergency Coordinator  Rep-
resentative  of  a facility covered by
environmental  law (e.g, a  chemical
plant) who participates in the emer-
gency reporting process with the Local
Emergency  Planning  Committee
(LEPC).

Facultative Bacteria: Bacteria that can
live under aerobic or anaerobic condit-
ions.

Feasibility Study: 1. Analysis of the
practicability of a proposal; e.g., a de-
scription  and  analysis  of  potential
cleanup alternatives for a site such as
one on the National Priorities List. The
feasibility study usually  recommends
selection of a cost-effective alternative.
It usually starts as soon as the remedi-
al investigation is underway;  together,
they are commonly referred to as the
"RVFS". 2. A small-scale investigation
of a  problem to ascertain whether  a
proposed research approach is likely to
provide useful data.

Fecal  Coliform  Bacteria:  Bacteria
found in the intestinal tracts of mam-
mals.  Their presence in water or
sludge is an indicator of pollution and
possible contamination by pathogens.

Federal Implementation  Plan: Under
current law, a federally implemented
plan to achieve attainment of air quali-
ty standards, used when a state  is
unable to develop an adequate plan.

Federal Motor  Vehicle  Control  Pro-
gram;  All  federal actions aimed at
controlling pollution from motor vehi-
cles by such efforts as establishing and
enforcing  tailpipe  and  evaporative
emission standards for new  vehicles,
testing  methods development,  and
guidance to states operating inspection
and maintenance programs.
Feedlot A confined area for the con-
trolled feeding  of animals. Tends to
concentrate  large amounts of animal
waste that cannot be absorbed by the
soil and,  hence,  may  be carried to
nearby streams or lakes by rainfall
runoff.
Fen: A type of  wetland that accumu-
lates peat deposits. Fens are less acidic
than bogs, deriving most of their water
from groundwater rich in calcium and
magnesium. (See: wetlands.)

FIFRA Pesticide Ingredient: An ingre-
dient of a pesticide that must be regis-
tered with  EPA under  the  Federal
Insecticide, fungicide, and Rodenticide
Act. Products making pesticide claims
must register  under FIFRA and may
be subject to labeling and use require-
ments.

Filling: Depositing dirt, mud or other
materials into aquatic areas to create
more dry land, usually for agricultural
or commercial development purposes,
often  with ruinous ecological conse-
quences.

Filter Strip: Strip or area of vegetation
used for removing sediment, organic
matter,  and  other  pollutants  from
runoff and waste water.

Filtration: A'treatment process, under
the control of  qualified  operators, for
removing solid  (particulate) matter
from water by means  of porous media
such as  sand  or a man-made  filter;
often  used to remove particles  that
containing pathogens.

Financial Assurance for Closure: Docu-
mentation or proof that an owner or
operator of a facility such as a landfill
or other waste repository is capable of
paying the projected  costs of closing
the facility  and monitoring  it  after-
wards  as provided in RCRA regula-
tions.

Finding of No Significant  Impact- A
document prepared by a federal agency
showing why a proposed action would
not have a significant impact on the
environment and thus would not re-
quire preparation of an Environmental
Impact Statement. An FNSI is based
on  the  results of an environmental
assessment.
Finished Water Water that has passed
through all the  processes in a water
treatment plant and is ready  to be
delivered to consumers.
First Draw: The water that comes out
when a tap is first opened, likely to
have the highest level of lead contam-
ination from plumbing materials.
Fix a Sample: A sample is "fixed" in
the field  by adding  chemicals  that
prevent water quality  indicators of
interest in the sample from changing
before  laboratory measurements are
made.
Flare:  A  control device that burns
hazardous materials to  prevent their
release into  the environment;  may
operate continuously or intermittently,
usually on top a stack.
Floe A clump of solids formed in sew-
age by biological or chemical action.

Flocculation: Process by which clumps
of solids in water or sewage aggregate
through biological or chemical action so

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                                                                                                            17
they can be separated from water or
sewage.
Floodplain: The flat or nearly flat land
along a river or stream or in a tidal
arra that is covered by water during a
flood.

Floor Sweep: Capture of heavier-than-
air gases that collect at floor level.

Flow Rate:  The rate, expressed in
gallons-or liters-per-hour, at which a
fluid escapes from a hole or fissure in
a tank. Such measurements are  also
made of liquid  waste, effluent,  and
surface water movement.
Flowmeter:  A gauge indicating the
velocity of wastewater moving through
a  treatment plant or of any  liquid
moving through  various  industrial
processes.
Flue Gas Desulfurization: A technology
that employs a sorbent, usually lime or
limestone, to  remove sulfur dioxide
from the gases produced  by burning
fossil fuels. Flue gas desulfurization is
current state-.of-the art technology for
major SO2 emitters, like power plants.
Flue Gas: The air coming out of  a
chimney after combustion in the burn-
er it is venting. It can include nitrogen
oxides,  carbon oxides, water vapor,
sulfur  oxides,  particles   and  many
chemical pollutants.
Fluidized: A mass of solid particles
that is made to  flow like  a liquid by
injection of water or gas is said to have
been fluidized. In water treatment, a
bed  of  filter  media is fluidized by
backwashing water through the filter.

Fluidized Bed Incinerator An inciner-
ator that uses a bed of  hot sand or
other granular material  to transfer
heat directly to waste. Used mainly for
destroying municipal sludge.
Fluoridation: The addition of n chemi-
cal to  increase  the concentration of
fluoride ions in drinking water to re-
duce the incidence of tooth decay in
children.

Flume: A natural or man-made chan-
nel that diverts water.
Fluorides: Gaseous, solid, or dissolved
compounds containing fluorine that re-
sult from industrial processes. Exces-
sive amounts in food can lead to fluoro-
sis.
Fluorocarbons (PCs): Any of a number
of organic  compounds analogous to
hydrocarbons  in  which  one or more
hydrogen atoms  are replaced by fluo-
rine. Once used  in the United States
as a propellant for domestic aerosols,
they are now found mainly in coolants
and  some  industrial  processes. PCs
containing   chlorine  are   called
chlorofluorocarbons  (CFCs). They are
believed to  be modifying the  ozone
layer in  the  stratosphere,  thereby
allowing more harmful solar radiation
to reach the Earth's surface.

Flush: 1. To open a cold-water tap to
clear out all the water which may have
been  sitting for a  long time  in  the
pipes. In new homes, to flush a system
means to send large volumes of water
gushing through the unused pipes to
remove loose particles of  solder and
flux. 2. To force large amounts of water
through liquid to clean out piping or
tubing,  storage or process tanks.

Flux: A flowing or flow.
Fly  Ash: Non-combustible  residual
particles expelled by flue gas.
Fogging: Applying a pesticide by rap-
idly heating the liquid chemical so that
it forms very fine droplets that resem-
ble smoke or fog. Used to destroy mos-
quitoes, black flies, and similar pests.

Food Chain: A sequence of organisms,
each of which uses the  next,  lower
member of  the  sequence  as a food
source.

Formaldehyde: A colorless, pungent,
and irritating gas, CH20, used chiefly
as a disinfectant and preservative and
in synthesizing other compounds Like
resins.
Formulation: The substances compris-
ing all active and inert ingredients in
a pesticide.
Fonil Fuel: Fuel driyed from ancient
organic remains, e.g., peat, coal, crude
oil, and natural gas.

Freeboard:  1.  Vertical distance from
the normal water surface to the top of
a confining wall. 2. Vertical distance
from the sand surface to the underside
of a trough in a sand filter.
Fresh  Water  Water  that generally
contains less than  1,000 milligrams-
per-liter of dissolved solids,

Friable Asbestos: Any material con-
taining more than one percent asbes-
tos, and that can be crumbled or re-
duced  to powder by  hand pressure.
(May include  previously  non-friable
material which  becomes  broken  or
damaged by mechanical force.)
Friable: Capable  of being crumbled,
pulverized, or reduced to  powder by
hand pressure.
Fuel Economy Standard: The Corpo-
rate Average Fuel Economy Standard
(CAFE) effective since 1978. It en-
hanced the national fuel conservation
effort imposing a miles-per-gallon floor
for motor vehicles.

Fuel Efficiency: The proportion of ener-
gy released by fuel combustionton that
is converted into useful energy.

Fuel Switching: 1.  A  precombustion
process whereby a low-sulfur coal is
used in place of a higher sulfur coal in
a power plant to reduce sulfur dioxide
emissions.  2. Illegally using leaded
gasoline in a motor vehicle designed to
use only unleaded.

Fugitive Emissions:  Emissions  not
caught by a capture system.
Fume: Tiny particles trapped  in vapor
in a gas stream.

Fumigant: A pesticide vaporized to kill
pests.  Used  in buildings and green-
houses. -

Functional Equivalent: Term used to
describe EPA's decision-making process
and its relationship to the environmen- •
tal review conducted under the Nation-
al Environmental Policy Act (NEPA). A
review is considered functionally equiv-
alent when it addresses the substan-
tive components of a NEPA review.
Fungi: (Singular: Fungus) Molds, mil-
dews, yeasts, mushrooms, and  puff-
balls,  a group of organisms lacking in
chlorophyll (i.e., are not photosynthet-
ic) and which 'are usually non-mobile,
filamentous, and multicellular. Some
grow in soil, others attach themselves
to decaying trees and other plants
whence they obtain nutrients. Some
are pathogens, others stabilize sewage
and digest composted waste.

Fungicide: Pesticides which are used to
control, deter, or destroy fungi.
Fungistafc A chemical that keeps fungi
from growing.

Furrow Irrigation: Irrigation method in
which water travels through the field
by means of small channels  between
each row or groups of rows.
Future Liability: Refers to potentially
responsible parties' obligations to pay
for additional response activities be-
yond those specified in the Record of
Decision or Consent Decree.
Game Fish: Species like trout, salmon,
or bass, caught  for sport. Many of

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 18
 them show more sensitivity to environ-
 mental change than "rough" fish.

 Garbage: Animal and vegetable waste
 resulting from the handling, storage,
 sale, preparation, cooking, and serving
 of foods.
 Gas Chromatograph/Mass Spectrome-
 ter Highly  sophisticated instrument
 that identifies the molecular composi-
- tion and. concentrations of  various
 chemicals in water and soil samples.

 Gasahol: Mixture of gasoline and etha-
 nol derived from fermented agricultur-
 al products  containing at least nine
 percent  ethanol.  Gasohol emissions
 contain  less  carbon monoxide  than
 those from gasoline.
 Gasification: Conversion of solid mate-
 rial such as coal into a gas for use as a
 fuel.

 Gasoline Volatility: The  property of
 gasoline whereby it evaporates into a
 vapor. Gasoline vapor is a volatile
 organic compound.

 General Permit: A permit applicable to
 a class or category of dischargers.

 General Reporting Facility:  A facility
 having one or more hazardous chemi-
 cals above the 10,000 pound threshold
 for planning quantities. Such facilities
 must file MSDS and emergency inven-
 tory information with the SERC and
 LEPC and local fire departments.
 Generator 1.  A  facuity or mobile
 source that emits pollutants into the
 air or releases hazardous waste into
 water or soil. 2. Any person, by site,
 whose act or process produces regulat-
 ed medical waste or whose  act first
 causes such waste to become subject to
 regulation. In a case where more than
 one person (e.g., doctors with separate
 medical  practices)  is located in the
 same building, each business entity is
 a separate generator.
 Genetic  Engineering: A  process  of
 inserting new genetic information into
 existing  cells in order to modify any
 organism for the purpose of changing
 one of its characteristics.

 Geographic Information System (618):
 A computer system designed for stor-
 ing,  manipulating  analysing,  and
 displaying data in a geographic con-
 text

 Geological Log: A detailed description
 of all underground features  (depth,
 thickness,  type of formations) discov-
 ered during the  drilling of a well.

 Geophysical Log: A record of the struc-
 ture and composition of the earth en-
countered when drilling a well or simi-
lar type of test hold or boring.

Germicide: Any  compound that kills
disease-causing microorganisms.

Giardia  Lambiia:  Protozoan in the
feces of  man  and animals that can
cause severe gastrointestinal ailments
when it contaminates drinking water.

Glovebag: A polyethylene or polyvinyl
chloride  bag-like  enclosure  affixed
around an asbestos-containing source
(most often thermal system insulation)
permitting the material to be removed
while minimizing release of airborne
fibers in the surrounding atmosphere.

Gooseneck: A portion of a water service
connection between the  distribution
system water main and a meter. Some-
times called a pigtail.

Grab Sample: A single sample collected
at a particular time and place that rep-
resents the composition of the water
only at that time and place.

Grain  Loading:  The rate  at which
particles  are emitted from a pollution
source. Measurement is made by the
number of grains per cubic foot of gas
emitted.

Granular Activated Carbon. Treatment:
A filtering system often used in small
water systems and individual homes to
remove organics. GAG can be highly ef-
fective in removing elevated levels of
radon from water.

Grassed  Waterway: Natural  or con-
structed watercourse or outlet that is
shaped or.graded and established in
suitable vegetation for the disposal of
runoff water without erosion.

Gray  Water:  Domestic  wastewater
composed of wash water from kitchen,
bathroom, and laundry sinks, tubs,
and washers.

Greenhouse Effect: The wanning of the
Earth's atmosphere attributed  to a
build-up of carbon dioxide or other gas-
es; some scientists think  that this
build-up allows the sun's rays to heat
the Earth, while infra-red radiation
makes the atmosphere  opaque  to a
counterbalancing loss of heat
Grinder Pump: A  mechanical device
that shreds solids and raises sewage to
a higher  elevation through pressure
sewers.

Ground Coven Plants grown to  keep
soil from  eroding.
Ground Water: The supply of fresh
water found beneath the Earth's sur-
face, usually in aquifers, which supply
wells and springs. Because  ground
water is a major  source of drinking
water, there  is growing concern over
contamination from leaching agricul-
tural or industrial pollutants or leak-
ing underground storage tanks.

Ground-Water   Discharge:   Ground
water entering  near  coastal waters
which has been contaminated by land-
fill leachate, deep well  injection  of
hazardous wastes,  septic tanks, etc.

Ground Water Under the Direct In-
fluence (UDI) of Surface Water Any
water beneath  the  surface of the
ground with: 1. significant occurence of
insects or other microorganims, algae,
or large-diameter pathogens; 2. signifi-
cant  and relatively  rapid shifts  in
water characteristcs such as turbidity,
temperature, conductivity, or pH which
closely correlate to climatological  or
surface water conditions. Direct influ-
ence  is  determined  for  individual
sources in accordance with criteria
established by the  state.

Gross Alpha/Beta Particle Activity: The
total radioactivity due to alpha or beta
particle emissions as  inferred  from
measurements on a dry sample.

Gully Erosion: Severe erosion in which
trenches  are  cut to a  depth greater
than 30 centimeters (a foot). Generally,
ditches deep enough to cross with farm
equipment are considered gullies.
H
Habitat: The place where a population
(e.g., human, animal, plant, microor-
ganism) lives  and its surroundings,
both living and non-living.
Habitat Indicator A physical attribute
of the environment measured to char-
acterize conditions necessary to sup-
port an organism, population, or com-
munity in the absence of pollutants,
e.g., salinity of esturarine waters or
substrate type in streams or lakes.
Half-Life:  1. The time required for a
pollutant to lose half its affect on the
environment. For example, the bio-
chemical half-life of DDT in the envi-
ronment is 15 years, of Radium. 1,580
years. 2. The time required for half of
the atoms of a radioactive element to
undergo self-transmutation or decay. 3.
The time required for the elimination
of one half a total dose from the body.

Halon: Bromine-containing compounds
with long atmospheric lifetimes whose
breakdown in the stratosphere causes
depletion of ozone. Halons are used in
fire-fighting.

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                                                                                                          19
Hammennill: A high-speed  machine
that uses  hammers and cutters to
crush, grind, chip, or shred solid waste.

Hard Water Alkaline water containing
dissolved salts that interfere with some
industrial  processes and prevent soap
from sudsing.

Hauler Garbage collection company
that offers complete refuse  removal
service; many  also will also collect
recyclables.

Hazard Communication  Standard: An
OSHA regulation that requires chemi-
cal manufacturers, suppliers, and im-
porters to assess the  hazards of the
chemicals  that they make, supply, or
import, and to inform employers, cus-
tomers, and workers of these hazards
through MSDS sheets.

Hazard Evaluation: A component of
risk evaluation that involves gathering
and evaluating data on the  types of
health  injury or disease that may be
produced by a chemical and on the con-
ditions of exposure under which such
health effects are produced.
Hazard Identification: Determining if a
chemical can  cause adverse health
effects  in  humans  and what those
affects might be.

Hazardous Air Pollutants: Air pollut-
ants which are not covered by ambient
air  quality standards but which, as
defined in the Clean Air Act, may
reasonably be expected to cause or
contribute  to  irreversible illness or
death. Such pollutants include asbes-
tos, beryllium, mercury, benzene, coke
oven emissions,  radionuclides,  and
vinyl chloride.

Hazardous Chemical: An  EPA designa-
tion for any hazardous material requir-
ing an MSDS under OSHA's Hazard
Communication Standard. Such sub-
stances are capable  of producing fires
and explosions or .adverse health ef-
fects like cancer and dermatitis. Haz-
ardous chemicals  are  distinct  from
hazardous  waste.  (See:  hazardous
waste.)

Hazardous Ranking System: The prin-
ciple screening tool used by EPA to
evaluate risks to public health and the
environment associated  'frith  aban-
doned or uncontrolled hazardous waste
sites.  The HRS calculates  a  score
based on the potential  of hazardous
substances spreading from  the  site
through the air, surface water, or
ground  water,  and on  other factors
such as density and proximity of hu-
man population. This score is the pri-
mary factor in deciding if  the  site
should be on the National Priorities
List and, if so, what ranking it should
have compared  to other sites on the
list.

Hazardous Substance: 1. Any material
that poses a threat to human health
and/or the environment. Typical haz-
ardous substances are toxic, corrosive,
ignitable,  explosive, or chemically re-
active. 2. Any substance designated by
EPA to be reported  if a designated
quantity of the substance is spilled in
the waters of the United States or  if
otherwise  released into the  environ-
ment.

Hazardous Waste: By-products of soci-
ety that can pose a substantial or po-
tential hazard to human health or the
environment when improperly man-
aged. Possesses at least one of four
characteristics (ignitability, corrosivity,
reactivity, or toxicity), or appears on
special EPA lists.

Hazardous Waste TjmHfill- An excavat-
ed or engineered site where hazardous
waste is deposited and covered.

Hazards Analysis: Procedures used to
(1) identify potential sources of release
of  hazardous materials  from fixed
facilities or transportation accidents;
(2)  determine the  vulnerability of  a
geographical area to a release of haz-
ardous materials; and (3) compare haz-
ards to determine which present great-
er or lesser risks to a  community.

Hazards  Identification:   Providing
information on  which facilities have
extremely hazardous substances, what.
those chemicals are, how much there is
at each facility, how the chemicals are
stored, and whether they are used at'
high temperatures.

Health Advisory Level: A non-regulato-
ry  health-based  reference   level of
chemical traces (usually in  ppm) in
drinking water at which there are no
adverse health  risks when  ingested
over various  periods of time. Such
levels are established for one day, 10
days, long-term and life-time exposure
periods. They contain  a wide margin of
safety.
Health Ai
at An evaluation of
available data on existing or potential
risks  to  human, health posed by a
Superfund site. The Agency for Toxic
Substances and Disease Registry (ATS-
DR) of the Department of Health and
Human Services (DHHS) is required to
perform such an assessment at every
site on the National Priorities Last.
Heat Island Effect: A "dome" of ele-
vated temperatures over an urban area
caused by  structural  and pavement
heat fluxes, and  pollutant emissions.

Heavy Metals: Metallic elements with
high atomic  weights, e.g., mercury,
chromium, cadmium, arsenic, and lead;
can damage living things at low con-
centrations and tend to accumulate in
the food chain.

Heptachlor  An insecticide that .was
banned on some food products in 1975
and all of them 1978. It was allowed
for use in seed treatment until 1983.
More recently it was found in milk and
other dairy products in Arkansas and
Missouri where dairy cattle were ille-
gally fed treated seed.

Herbicide:  A chemical pesticide  de-
signed  to control or destroy  plants,
weeds, or grasses.

Herbivore:  An animal that feeds on
plants.

Heterotrophic Organisms: Species that
are dependent on organic  matter for
food.

High-Density Polyethylene: A material
used to make plastic bottles and other
products that produces  toxic  fumes
when burned.

High-Level Radioactive Waste (HLW):
Waste generated in core fuel of a nu-
clear reactor or by nuclear fuel repro-
cessing; is a serious threat to  anyone
who comes near the waste without shi-
elding.   (See:  low-level  radioactive
waste.)

High-Level Nuclear Waste Facility:
Plant designed to handle  disposal of
used nuclear fuel, high-level radioac-
tive waste, and plutonium waste.

High-Line Jumpers: Pipes or hoses
connected to fire hydrants and laid on
top of the ground to provide emergency
water service for an isolated portion of
a distribution system.

High-Risk Community: A community
located within the vicinity of numerous
sites of  facilities or other potential
sources   of environrnmental  expo-
sure/health hazards which may result
in high levels of exposure to contami-
nants or pollutants.

Holding  Pond: A pond  or reservoir,
usually  made of earth, built to store
polluted runoff.

Homeowner Water System: Any water
system which supplies piped water to
a single residence.

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20
Homogeneous Area: In accordance with
Asbestos Hazard and Emergency  Re-
sponse  Act (AHERA) definitions, an
area of surfacing materials,  thermal
surface insulation,  or miscellaneous
material that is uniform in color and
texture.

Hood Capture Efficiency: Ratio of the
emissions captured by a hood and dire-
cted into a control or disposal device;
expressed as a percent of all emissions.

Host: 1. In  genetics, the organism,
typically a  bacterium, into  which a
gene from another organism is trans-
planted.  2.  In  medicine,  an animal
infected  or  parasitized  by  another
organism.

Household  Waste (Domestic  Waste):
Solid waste, composed of garbage and
rubbish, which normally originated in
a private home  or apartment house.
Domestic waste may contain a signifi-
cant amount of toxic or hazardous
waste.
Human  Equivalent   Dose:  A dose
which, when administered to humans,
produces an effect equal to that pro-
duced by a  dose in animals.

Human Exposure Evaluation: Describ-
ing the nature and size of the popula-
tion exposed to  a substance and  the
magnitude  and duration of their expo-
sure.
Human Health  Risk: The likelihood
that a given exposure or series of expo-
sures may  have or will damage  the
health of individuals.

Hydraulic Gradient:  In general,  the
direction of groundwater flow due to
changes in the  depth of the water
table.
Hydrocarbons (HO   Chemical com-
pounds that consist entirely of carbon
and hydrogen.

Hydrogen Sulfide (HS> Gas  emitted
during organic decomposition. Also a
by-product of oil refining and burning.
Smells like rotten eggs and, in heavy
concentration, can kill or cause illness.

Hydrogeological  Cycle:  The  natural
process recycling water from the atmo-
sphere  down to (and through)  the
earth and  back to  the  atmosphere
again.
Hydrogeology: The geology of ground
water, with particular emphasis on the
chemistry and movement of water.
Hydrologic  Cycle: Movement or  ex-
change of water between the atmo-
sphere  and earth.
Hydrology: The science dealing with
the properties, distribution, and cir-
culation of water.

Hydrophilic: Having a strong affinity
for water.

Hydrophobic: Having a strong aversion
for water.

Hydropneumatic:  A water  system,
usually small,  in which a water pump
is automatically controlled by the pres-
sure in a compressed air tank.

Hypolimnion: Bottom waters of a ther-
mally stratified lake., The hypolimnion
of a eutrophic lake is usually low or
lacking in oxygen.
I

Identification Code or EPA I.D. Num-
ber The unique code assigned to each
generator, transporter, and treatment,
storage, or disposal facility by regu-
lating agencies to facilitate identifica-
tion and tracking of chemicals or haz-
ardous waste.

Ignitable: Capable of burning or caus-
ing a fire.

Imhoff Cone: A clear, cone-shaped con-
tainer used to measure the volume of
settleable solids in a specific volume of
water.
Immediately Dangerous to Life
Health CEDLH): The' maximum level to
which a healthy individual  can  be
exposed to a chemical for 30 minutes
and escape without suffering irrevers-
ible health effects or impairing symp-
toms. Used  as  a "level of concern."
(See: level of concern.)

Impermeable: Not easily    penetrat-
ed. The  property of a material or soil
that does not allow, or allows only with
great difficulty, the movement or pas-
sage of water.
Impoundment: A body  of  water or
sludge confined by a dam, dike, flood-
gate, or  other barrier.
         Command Post:  A  facility
located  at  a safe  distance from  an
emergency  site,  where  the  incident
commander, key staff,  and technical
representatives can make   decisions
and deploy emergency manpower and
equipment.
        Command System (ICS): The
organizational arrangement  wherein
one person, normally the Fire Chief of
the impacted district, is in charge of an
integrated, comprehensive  emergency
response organization and the emer-
gency  incident site,  backed by  an
Emergency  Operations  Center  staff
with resources, information, and ad-
vice.

Incineration: A treatment technology
involving destruction of waste by con-
trolled burning at high temperatures,
e.g., burning  sludge  to  remove  the
water and reduce the remaining resi-
dues to a safe, non-burnable ash that
can be disposed of safely on land, in
some waters, or in underground loca-
tions.

Incineration at Sea: Disposal of waste
by burning at sea on specially-designed
incinerator ships.

Incinerator: A furnace  for burning
waste under controlled conditions.
Incompatible Waste: A waste unsuit-
able for mixing with another waste or
material because it may react to form
a hazard.

Indicator: In biology, an organism, spe-
cies, or community whose characteris-
tics show the presence of specific envi-
ronmental conditions. 2. In chemistry,
a substance   that shows  a > visible
change, usually of color, at a desired
point in a chemical reaction. 3.A device
that indicates the result of a measu-
rement.

Indirect Discharge: Introduction of pol-
lutants from a non-domestic source
into a publicly owned waste-treatment
system. Indirect dischargers  can be
commercial  or industrial  facilities
whose wastes enter local sewers.

Indirect Source: Any facility or build-
ing, property, road or parking  area
that attracts motor vehicle traffic and,
indirectly, causes pollution.

Indoor Air  The breathing air inside a
habitable structure or conveyance.
Indoor Air Pollution: Chemical, physi-
cal, or biological contaminants in in-
door air.
Indoor Climate: Temperature, humidi-
ty, lighting, and noise levels in a habit-
able structure or  conveyance. Indoor
climate can affect indoor air pollution.
Industrial Pollution Prevention:  Com-
bination of industrial source reduction
and toxic chemical use substitution
Industrial Source Reduction: Practices
that reduce the amount of any hazard-
ous substance, pollutant, or contami-
nant entering any  waste stream  or
otherwise released into  the environ-
ment; also reduces the threat to public
health and the environment associated
with  such  releases.  Term  includes
equipment or technology modifications,

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                                                                                                             21
 substitution of  raw  materials,  and
 improvements in housekeeping, main-
 tenance, training or inventory control.

 Industrial Waste: Unwanted materials
 from an industrial operation; may be
 liquid, sludge,  solid,  or  hazardous
 waste.

 Inert Ingredient: Pesticide components
 such  as  solvents,  carriers,  dispers-
 ants.and surfactants that are  not ac-
 tive against target pests. Not all inert
 ingredients are, innocuous.

 Inertia! Separator: A device that uses
 centrifugal force to separate  waste
 particles.

 Infectious Agent Any organism, such
 as a virus or bacterium, that is path-
 ogenic and capable of being communi-
 cated by invasion and multiplication in
 body tissues.

 Infectious Waste:  Hazardous  waste
 with infectious characteristics, includ-
 ing: contaminated animal waste; hu-
 man blood and blood products; isola-
 tion  waste,  pathological waste;  and
 discarded sharps (needles, scalpels or
 broken medical instruments.)

 Infiltration: 1. The penetration of wa-
 ter through the ground surface  into
 sub-surf ace soil or the penetration of
 water from the soil into sewer or other
 pipes through  defective joints, connec-
 tions, or  manhole walls. 2. The tech-
 nique of  applying  large volumes of
 waste water to land to penetrate the
 surface  and   percolate  through  the
. underlying soil. (See: percolation.)

 Infiltration  Gallery:  A sub-surface
 groundwater collection system, typical-
 ly shallow in depth, constructed with
 open-jointed or perforated pipes that
 discharge collected water into a water-
 tight chamber  from which the water is
 pumped to treatment facilities and into
 the distribution system. Usually locat-
 ed close to streams or ponds.

 Infiltration Rate: The quantity of water
 than can enter the  soil in a specified
 time interval.

 Inflow: Entry of extraneous rain water
 into a sewer system from sources other
 than  infiltration, such  as basement
 drains, manholes, storm drains,  and
 street washing.

 Influent: Water, wastewater, or other
 liquid flowing into a reservoir, basin,
 or treatment plant.

 Information File: In the Superfund
 program, a file that  contains accurate,
 up-to-date documents on a Superfund
site. The file is usually located in a
public building (school, library, or city
hall) convenient for local residents.

Initial Compliance Period(water): The
first full three-year compliance period
which begins at least 18 months after
promulgation.

Injection Well: A well into which fluids
are injected for purposes such as waste
disposal, improving  the  recovery  of
crude oil, or solution mining.

Injection Zone: A geological formation
receiving fluids through a well.

In-Ldne  Filtration: Pre-treatment met-
hod in which chemicals are mixed  by
the flowing water; commonly used in
pressure filtration installations. Elimi-
nates need for flocculation and sedi-
mentation.
Innovative Technologies: New or inven-
tive methods to treat effectively haz-
ardous waste and reduce risks to hu-
man health and the environment.

Inoculum: 1. Bacterium placed in com-
post to  start  biological action. 2. A
medium containing organisms that is
introduced into cultures or living  or-
ganisms.

Inorganic Chemicals: Chemical sub-
stances  of mineral origin, not of basi-
cally carbon structure.
Insecticide: A pesticide compound spe-
cifically used  to kill  or  prevent the
growth of insects.
Inspection and MaiTit«tianc« (J/M): 1.
Activities to assure that vehicles' emis-
sions-controls  work properly. 2. Also
applies to wastewater treatment plants
and other anti-pollution facilities and
processes.
Instream Use: Water use taking place
within a stream channel, e.g., hydro-
electric power generation, navigation,
water quality improvement, fish propa-
gation, recreation.
In-Situ Stripping: Treatment  system
that remove or "strips" volatile organic
compounds from contaminated ground
or surface  water by  forcing an air-
stream through the water and causing
the compounds to evaporate.
Integrated Eipueure Assessment Cu-
mulative summation (over time) of the
magnitude of exposure to a toxic chem-
ical in all media.
Integrated Pest Management (TPM): A
mixture of chemical and other, non-pe-
sticide, methods to control pests.
Integrated Waste Management Using
a variety of practices to handle munici-
pal solid  waste; can include source
reduction, recycling, incineration, and
landfilling.

Interceptor Sewers: Large sewer lines
that, in a combined system, control the
flow of sewage to the treatment plant.
In a storm, they allow some of the sew-
age to flow directly into  a  receiving
stream, thus keeping it from overflow-
ing onto the streets. Also used in sepa-
rate systems to collect the flows from
main and trunk sewers and carry them
to treatment points.

Interface:  The common boundary be-
tween two substances such as a water
and a solid, water and a  gas, or two
liquids such as water and oil.

Interim (Permit) Status: Period during
which treatment, storage and disposal
facilities coming under RCRA in 1980
are temporarily  permitted to operate
while awaiting a permanent permit.
Permits issued  under these circum-
stances are usually called "Part A" or
"Part B" permits.
Interstate  Carrier  Water Supply:  A
source of water for drinking  and sani-
tary use on planes, buses, trains, and
ships operating in more than  one state.
These sources  are federally regulated.

Interstate Commerce Clause: A clause
of the U.S. Constitution which reserves
to the federal government the right to
regulate the conduct of business across
state lines. Under this clause, for ex-
ample, the U.S. Supreme Court has
ruled that states may not inequitably
restrict the disposal out-of-state wastes
in their jurisdictions.

Interstate Waters:  Waters  that  flow
across or form part of state or inter-
national  boundaries,  e.g., the  Great
Lakes, the Mississippi River, or coastal
waters.
Interstitial Monitoring: The continuous
surveillance of the space between the
walls of an underground storage tank.
Inventory (TSCA): Inventory of chemi-
cals produced pursuant to Section 8 (b)
of the Toxic Substances Control Act.
Inversion: A layer of warm air prevent-
ing the rise of cooling air and pollut-
ants trapped beneath it. Can cause an
air pollution episode.  ,
Ion: An electrically charged atom that
can be drawn from waste water during
electrodialysis.
                                                                                           J.S.

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22
Ion Exchange Treatment: A common
water-softening method often found on
a  large  scale at  water purification
plants that remove some organics and
radium  by adding  calcium oxide or
calcium hydroxide to increase the pH
to a level where the metals will pre-
cipitate  out.

lonization  Chamber:  A device that
measures the  intensity of  ionizing
radiation.     '                 . .

Ionizing Radiation: Radiation that can
strip electrons from atoms, .i.e.,  alpha,
beta, and gamma radiation.

Irradiated Food: Food subject to brief
radioactivity, usually gamma rays, to
kill insects, bacteria, and mold, and to
permit storage without refrigeration.

Irradiation: Exposure to radiation of
wavelengths shorter than those of visi-'
ble light (gamma, x-ray, or ultraviolet),
for medical purposes, to sterilize milk
or other foodstuffs, or to induce poly-
merization of monomers or vulcaniza-
tion of rubber.
Irreversible Effect; Effect characterized
by the inability of the body to partially
or fully repair injury caused by a toxic
agent.

Irrigation: Applying water  or waste-
water to land areas to supply the. wa-
ter and nutrient needs of plants.
Irrigation Efficiency: The amount of
water stored in the crop root zone com-
pared to the amount of irrigation water
applied.
Irrigation Return Flow: Surface and
subsurface water which leaves the field
following application of irrigation wa-
ter.

Irritant A substance that can cause
irritation of the skin, eyes, or respira-
tory system. Effects may be acute from
a single high-level exposure, or chronic
from repeated low-level exposures to
such compounds as chlorine, nitrogen
dioxide,  and nitric acid.
Isotope: A variation of an element that
has the  same atomic number of pro-
tons but a different weight because of
the number of neutrons. Various  iso-
topes of the same element may have
different radioactive behaviors, some
are highly unstable..
Jar Test: A laboratory procedure that
simulates a water treatment plant's co-
agulation/Qocculation units with dif-
fering chemical doses, mix speeds, and
settling times to estimate the mini-
mum or ideal coagulant dose required
to achieve certain water quality goals.
Karat: A geologic formation of irregular
limestone deposits with sinks, under-
ground streams, and caverns.

Kinetic Energy: Energy possessed by a
moving body of water as a result of its
motion.

Kinetic  Rate  Coefficient: A  number
that describes the rate at which  a
water constituent such as a biochemi-
cal oxygen demand or dissolved oxygen
rises or  falls.
Lagoon: 1. A shallow pond where sun-
light, bacterial  action, and oxygen
work to purify wastewater; also  used
for storage  of  wastewater  or spent
nuclear fuel rods. 2. Shallow body of
water, often separated from the sea by
coral reefs or sandbars.
Land Application: Discharge  of waste-
water onto the ground for treatment or
reuse. (See: irrigation.)

Land Ban: Phasing out of land disposal
of most untreated hazardous wastes,
as  mandated by the  1984  RCRA
amendments.
Land Fanning (of waste): A disposal
process in which hazardous waste de-
posited on or in the soil is degraded
naturally by microbes.
        ? i. Sanitary landfills are dis-
posal sites  for  non-hazardous solid
wastes spread in layers, compacted to
the  smallest practical  volume, and
covered by material applied at the end
of each operating day. 2. Secure chemi-
cal landfills are disposal sites for haz-
ardous waste, selected and designed to
         the chance of release of haz-
ardous substances into the environ-
ment.
Landscape:  The traits, patterns, and
structure of a specific geographic area,
including its biological composition, its
physical environment, and its anthro-
pogenic or social patterns.  An area
where  interacting   ecosystems   are
grouped and repeated in similar form.
Landscape Characterization:  Docu-
mentation of the traits and patterns of
the essential elements of the land-
scape.
Landscape Ecology:  The study of the
distribution patterns of communities
and ecosystems, the ecological process-
es  that  affect those  patterns, and
changes in pattern and process over
time.

Landscape Indicator  A measurement
of  the  landscape,  calculated  from
mapped or remotely sensed data, used
to describe spatial patterns of land use
and land  cover  across a geographic
area.  Landscape  indicators may  be
useful as measures of certain kinds of
environmental  degradation such  as
forest fragmentation.

Langelier  Index (LI): An index reflect-
ing the equilibrium pH of a water with
respect to  calcium and alkalinity; used
in stabilizing water to control  both
corrosion and scale deposition.

Large Quantity Generator Person  or
facility  generating more  than  2200
pounds of  hazardous waste per month.
Such generators produce about 90 per-
cent of the nation's hazardous waste,
and are subject to all RCRA require-
ments.

Large Water System: A water system
that services more than 50,000 custom-
era.

Latency: Time from the first exposure
of a chemical until the appearance of a
toxic effect.

Lateral Sewers: Pipes that run under
city  streets and receive the sewage
from homes and businesses, as opposed
to domestic feeders  and main trunk
lines.
           Weir Sedunention basin
overflow weir.
LC50/Lethal c Concentration:  Median
level concentration, a standard mea-
sure of toxitity. It tells how much of a
substance is  needed to kill half of a
group of experimental organisms in a
given time. (See: LD50.)
Lt> 50/ Lethal Dose: The dose of a
toxicant that will kill 50 percent of the
test  organisms  within a designated
period. The lower the LD  50, the more
toxic the compound.

Leachate: Water that collects contami-
nants as it trickles through wastes,
pesticides or fertilizers. Leaching may
occur in farming areas, feedlots, and
landfills, and may result in hazardous
substances entering  surface  water,
ground water, or soil.
Leachate Collection System: A system
that gathers leachate and pumps it to
the surface for treatment.

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                                                                                                           23
   phing; The process by which soluble
constituents are dissolved and filtered
through the soil by a percolating fluid.
(See: leachate.)

Lead (Pb): A heavy metal that is haz-
ardous to health if breathed or swal-
lowed. Its use in gasoline, paints, and
plumbing compounds has been sharply
restricted or eliminated by federal laws
and regulations. (See: heavy metals.)
Lead Service Lin«v A service line made
of lead which connects the water to the
building inlet and any lead fitting con-
nected to it.
Legionella: A genus .of bacteria, some
species of which have caused a type of
pneumonia called Legionaires Disease.

Level of Concern (LOG):  The concen-
tration in air of an extremely hazard-
ous substance above which there may
be serious immediate health effects to
anyone exposed to it for short periods
Lifetime  Exposure: Total amount of
exposure to a substance that a human
would receive in a lifetime (usually
assumed to be 70 years).

Lift: In a sanitary landfill, a compacted
layer of solid waste and the top layer
of cover material.
T.ifHng Station: (See: pumping station.)

Limestone Scrubbing: Use of a lime-
stone  and water solution to remove
gaseous  stack-pipe sulfur  before it
reaches the atmosphere.
Limited Degradation: An. environmen-
tal policy permitting some degradation
of natural systems but terminating at
a level well beneath  an established
health standard.
Limiting Factor A condition whose ab-
sence  or excessive concentration, is
incompatible with the needs or toler-
ance of a species  or population and
which may have a negative influence
on their ability to thrive, survive.

Limnology: The study of the physical,
chemical, hydrological,  and biological
aspects of fresh water bodies.
        - A pesticide that causes ad-
verse health effects in domestic water
supplies and is toxic to freshwater fish
and aquatic life.

Linen  LA  relatively  impermeable
barrier designed to keep leachate in-
side a landfill. Liner materials include
plastic and dense clay. 2. An insert or
sleeve for sewer pipes to prevent leak-
age or infiltration.
Lipid Solubility: The maximum concen-
tration of a chemical that will dissolve
in fatty substances. Lipid soluble sub-
stances are insoluble in water. They
will very selectively disperse through
the environment via uptake in living
tissue.

Liquefaction:  Changing a solid into a
liquid.
Liquid Injection Incinerator Common-
ly used system  that relies on .high
pressure to prepare liquid wastes for
incineration,  breaking  them up into
tiny droplets  to allow easier combus-
tion.
List Shorthand term for EPA list of
violating  facilities or firms debarred
from obtaining government contracts
because they  violated certain sections
of the Clean Air or Clean Water Acts.
The list is maintained by The Office of
Enforcement  and Compliance  Moni-
toring.
Listed Waste: Wastes listed as hazard-
ous under RCRA but which have not
been subjected to the Toxic Character-
istics Listing Process because the dan-
gers they present are considered self-
•evident.

Litter" The highly visible portion of
solid waste  carelessly discarded outside
the regular garbage and trash collec-
tion and disposal system.

Littoral Zone: 1. That portion of a body
of fresh  water extending  from the
shoreline lakeward to the limit of occu-
pancy of rooted plants. 2. A strip of
land along  the shoreline between the
high and low  water levels.

Local Education Agency (LEA): In the
asbestos  program,  an  educational
agency at the local level that exists
primarily to operate schools or to con-
tract for educational services, including
primary and  secondary  public and
private schools. A single, unaffiliated
school can  be considered an LEA for
AHERA purposes.
Local Emergency Planning Committee
(LEPO A committee appointed by the
State  Emergency Response Commis-
sion, as required by SARA Title III, to
formulate a comprehensive emergency
plan for its jurisdiction.

Low NO, Burners: One of several com-
bustion technologies used  to reduce
emissions of Nitrogen Oxides (NO1.)
Loweat-Oberved-Adverse-Effect Level:
The  lowest dose in an experiment
which produced an observable adverse
effect
Low-Level Radioactive Waste (LLRW):
Wastes  less hazardous than  most of
those associated with nuclear reactor;
generated by hospitals, research labo-
ratories, and certain industries. The
Department of Energy, Nuclear Regu-
latory Commission, and EPA share
responsibilities  for managing them.
(See: high-level radioactive wastes.)

Lower Explosive Limit (LEL): The con-
centration of a compound in air below
which the mixture will not  catch on
fire.

Lowest  Achievable Emission  Rate:
Under the Clean Air Act, the rate of
emissions that reflects  (1) the most
stringent emission limitation in the im-
plementation plan of any state for such
source unless the  owner or operator
demonstrates such limitations are not
achievable; or (2) the most stringent
emissions limitation achieved in prac-
tice, whichever is  more  stringent. A
proposed new or modified source may
not emit pollutants in excess  of exist-
ing new source standards.
M

Magnetic Separation: Use of magnets
to separate .ferrous materials from
mixed municipal waste stream.
Managerial   Controls:   Methods   of
nonpoint source pollution control based
on decisions about managing agricul-
tural  wastes or  application times or
rates  for agrochemicals.

Mandatory Recycling: Programs which
by law require consumers to separate
trash so that some or all recyclable
materials  are recovered for recycling
rather than going to landfills.

Man-Made Beta Particle and Photon
Emitters:  All radionuclides emitting
beta particles and/or photons listed in
Maximum Permissible  Body Burdens
and Maximum Permissible Concentra-
tions  of Radionuclides in Air and Wa-
ter for Occupational Exposure.
Manual Separation: Hand sorting of
reyclable or compostable materials in
waste.
Major Modification: This term is used
to define modifications of major  sta-
tionary sources of emissions with re-
spect to Prevention of Significant Dete-
rioration and New Source Review un-
der the Clean Air Act.

Major Stationary Sources: Term used
to determine the applicability of Pre-
vention of Significant  Deterioration

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 24
 and new  source  regulations. In  a
 nonattainment area, any  stationary
 pollutant source with potential to emit
 more than 100 tons per year is consid-
 ered a major stationary source. In PSD
 areas the  cutoff level may be either
 100 or 250 tons, depending upon the
 source.

 Majors: Larger publicly owned treat-
 ment works (POTWs) with flows equal
 to at least one million gallons per day
 (mgd) or servicing population equiva-
 lent to  10,000 persons; certain other
 POTWs having significant water quali-
 ty impacts. (See: minors.)

 Management Plan: Under the Asbestos
 Hazard  Emergency  Response  Act
 (AHERA), a document that each Local
 Education  Agency is required to pre-
 pare, describing all activities planned
 and undertaken by a school to comply
 with AHERA regulations,  including
 building inspections to identify asbes-
 tos-containing  materials,   response
 actions,  and operations and mainte-
 nance programs to minimize the risk of
 exposure.
 Manifest System: Tracking of hazard-
 ous waste from "cradle to grave" (gen-
 eration through disposal) with accom-
 panying  documents known as  mani-
 fests. (See: cradle to grave.)

 Manual Separation: Hand  separation
 of compostable or recyclable material
 from waste.

 Manufacturers Formulation: A list of
 substances or component parts as de-
 scribed  by  the maker of  a coating,
 pesticide, or other product  containing
 chemicals or other substances.
 Margin of Safety. Maximum amount of
 exposure  producing no  measurable
 effect in  animals (or studied humans)
 divided by the actual amount of human
 exposure in a population.
Marine Sanitation Device: Any equip-
ment or  process installed on board a
 vessel to receive, retain, treat, or dis-
 charge sewage.

Marsh: A type of wetland that does not
 accumulate appreciable peat deposits
 and is dominated by herbaceous vege-
 tation. Marshes may be either fresh or
 saltwater,  tidal or  non-tidal. (See:
 wetlands.)

Material Category: In the asbestos pro-
 gram, broad classification of materials
 into thermal surfacing insulation, sur-
 facing  material,  and  miscellaneous
 material.
 Materials Recovery Facility: A facility
 that processes residentially collected
mixed recyclables into new products
available for market.

Material Type:  classification of sus-
pect material by  its  specific use  or
application, e.g., pipe  insulation, fire-
proofing, and floor tile.

Material Safety Data Sheet (MSDS): A
compilation of information required
under the OSHA Communication Stan-
dard  on the  identity of hazardous
chemicals,  health, and physical  haz-
ards, exposure limits, and precautions.
Section 311 of SARA requires facilities
to submit MSDSs under certain cir-
cumstances:

Materials Recovery Facility (MRF):
Facility that  processes residentially
collected mixed recyclables into new
products.
Maximum  Contaminant  Level:  The
maximum permissible level of a con-
taminant in water delivered to any
user of a public system. MCLs are
enforceable standards.
           Contaminant Level Goal
(MCLG): Under  the  Safe Drinking
Water Act, a non-enforceable, concen-
tration of a drinking  water contami-
nant, set at the level  at which no
known or anticipated adverse effects
on  human health occur  and which
allows an   adequate  safety margin.
The MCLG is usually the starting
point for determining the regulated
Maximum  Contaminant Level. (See;
Maximum Contaminant Level.)

Maximum Tolerated Dose: The maxi-
mum dose that an animal species ran
tolerate for a major portion of its life-
time without significant impairment or
toxic effect other than  carcinogenicity.
M«M»imiiiMil Aeration: Use of mechani-
cal  energy to inject air  into water to
cause a waste stream to absorb oxy-
gen.
M«n4»«niMil Separation: Using mechan-
ical mnana to separate waste into vari-
ous components.
MiM-haniral Turbulence: Random irreg-
ularities of fluid motion in air caused
by  buildings or  other  non-thermal,
processes.
Madia: Specific environments-air, wa-
ter, soil-which are the subject of regu-
latory concern and activities.
Medical Surveillance:  A periodic com-
prehensive review of a worker's health
status;  acceptable elements of such
surveillance program are listed in the
Occupational Safety and Health Ad-
ministration standards for asbestos.
Medical Waste: Any solid waste gener-
ated in the diagnosis, treatment, or
immunization of human beings or ani-
mals, in research pertaining thereto, or
in  the.  production  or  testing  of
biologicals, .excluding hazardous waste
identified or listed under 40 CFR Part
261 or any household waste as defined
in 40 CFR Sub-section 261.4 (bXD).

Medium-size Water System: A water
system  that  serves  3,300 to 50,000
customers.

Meniscus: The curved top of a column
of liquid in a small tube.

Mercury: A heavy metal that can accu-
mulate in the environment and is high-
ly toxic if breathed or swallowed. (See:
heavy metals.)

Mesotrophic   Reservoirs  and lakes
which contain moderate quantities of
nutrients and are moderately product-
ive in  terms of aquatic  animal and
plant life.

Metabolites: Any substances produced
by biological processes, such as those
from pesticides.
Metalimnion: The middle layer  of a
thermally stratified lake  or reservoir.
In this layer there is a rapid decrease
in temperature with depth. Also called
thermocline.

Methane: A colorless, nonpoisonous,
flammable  gas created by anaerobic
decomposition of organic compounds.

Methanol: An alcohol that can be used
as an alternative fuel or as a gasoline
additive. It is less volatile than gaso-
line; when blended with gasoline it
lowers the carbon monoxide emissions
but increases hydrocarbon emissions.
Used as  pure fuel,  its emissions are
less  ozone-forming  than  those from
gasoline.
Method 18: An EPA test method which
uses gas chromatographic techniques
to measure the concentration of vola-
tile  organic  compounds in  a   gas
stream.
Method 24: An EPA reference method
to determine density, water content
and total volatile content (water and
VOC) of coatings.
Method 25: An EPA reference method
to determine the VOC concentration in
a gas stream.
Methoxychlor: Pesticide  that causes
adverse  health effects  in  domestic
water -supplies and is toxic to fresh-
water and marine aquatic life.

Methyl Orange Alkalinity: A measure
of the total alkalinity in a water sam-

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                                                                                                          25
pie in wich the color of methyl orange
reflects the change in level.

Microbial  Growth: The  activity and
growth of microorganisms  such as
bacteria, algae, diatoms, plankton, and
fungi.
Microclimate: The localized  climate
conditions  within  an  urban  area or
neighborhood.

Microbial  Pesticide: A microorganism
that is used to  control a pest, but of
minimum  toxicity to man.

Million-gallons  Per Day  (MOD):  A
measure of water flow.

Minimization: A  comprehensive pro-
gram to minimize or eliminate wastes,
usually applied to wastes at their point
of origin. (See: waste minimization.)

Mining of an Aquifer Withdrawal over
a period of time of ground water that
exceeds the rate of recharge of the
aquifer.

Minors: Publicly  owned  treatment
works  with flows less than 1 million
gallons per day. (See: majors.)

Miscellaneous ACM: Interior asbestos-
containing building material or  struc-
tural components, members or fixtures,
such as floor and ceiling tiles; does not
include surfacing materials or thermal
system insulation.

Miscellaneous  materials:  Interior
building materials on  structural com-
ponents, such as floor or ceiling tiles.

Miscible Liquids: Two or more liquids
that can be mixed and will remain
mixed under normal conditions.

Missed Detection:  The situation that
occurs  when a  test indicates that  a
tank is "tight" when in fact it is leak-
ing.
Mist: Liquid particles measuring 40 to
500 microns, formed by condensation of
vapor. By comparison, fog particles are
smaller than 40 microns.

Mitigation: Measures taken to reduce
adverse impacts on the environment.

Mixed  Funding: Settlements in which
potentially responsible  parties and
EPA share the  cost of a response ac-
tion.

Mixed  Liquor: A mixture of activated
sludge and water containing organic
matter undergoing activated sludge
treatment in an aeration tank.

Mobile Incinerator Systems: Hazardous
waste  incinerators that can be trans-
ported from one site to another.
Mobile  Source:  Any  non-stationary
source of air pollution such as cars,
trucks, motorcycles, buses, airplanes,
locomotives.
Model Plant:  A  hypothetical plant
design used for developing economic,
environmental,  and energy  impact
analyses as support for regulations or
regulatory  guidelines;  first  step in
exploring the economic impact of a
potential NSPS.
Modified Source: The enlargement of a
major stationery pollutant sources is
often  referred to as modification, im-
plying that more emissions wil occur.
Molecule: The smallest division of a
compound that still retains or exhibits
all the properties of the substance.
Molten Salt Reactor A thermal treat-
ment unit that rapidly heats waste in
a heat-conducting  fluid bath of car-
bonate salt.
Monitoring: Periodic or continuous sur-
veillance or testing to determine the
level of compliance with statutory re-
quirements and/or  pollutant levels in
various media or in humans, plants,
and animals.
Monitoring Well:  1. A well used to
obtain water quality samples or mea-
sure groundwater levels. 2. Well drilled
at a  hazardous waste management
facility or  Superfund  site to collect
ground-water samples  for the purpose
of physical, chemical, or biological
analysis to  determine the  amounts,
types, and distribution of contaminants
in the ground water beneath the site.
Monoclonal  Antibodies: (Also called
MABs and MCAs) 1. Man-made clones
of a molecule, produced in quantity for
medical or research purposes. 2. Mole-
cules  of living organisms that selec-
tively find and  attach to other mole-
cules to which their structure conforms
exactly. This could also apply to equiv-
alent  activity by chemical molecules.
Monomictic  Lakes  and  reservoirs
which are relatively deep, do not freeze
over during winter, and undergo  a
single stratification and mixing cycle
during the year (usually in the fall).
Moratorium: During the negotiation
process, a period of 60 to 90 days dur-
ing which EPA and potentially respon-
sible parties may reach settlement but
no site response activities can be con-
ducted.
Morbidity: Rate of disease incidence.
Most  Probable Number  The  most
probable number  of colifonn-group
organisms per unit of volume of a
water sample

Muck Soils: Earth made from decaying
plant  materials.

Mudballs: Round material that forms
in filters and gradually increases in
size when not removed by backwash-
ing.

Mulch: A layer of material (wood chips,
straw, leaves, etc.)  placed  around
plants to hold moisture, prevent weed
growth, and enrich or sterilize the soil.
Multiple Use: Use of land for  more
than one purpose; i.e., grazing of live-
stock, watershed and wildlife protec-
tion, recreation,  and timber produc-
tion. Also applies to use of bodies of
water for recreational purposes,  fish-
ing, and water supply.

Multistage Remote Sensing: A strate-
gy for landscape characterization that
involves gathering and analyzing infor-
mation at several geographic scales,
ranging  from generalized levels of
detail at the  national level through'
high levels of detail at the  local scale.

Municipal  Discharge:  Discharge of
effluent from waste water treatment
plants which receive waste water from
households,   commercial   establish-.
ments,  and  industries.   Combined
sewer/separate storm overflows are in-
cluded in this category.

Municipal Sewage: Wastes  (mostly liq-
uid) orginating from a community; may
be composed of domestic wastewaters
and/or industrial discharges.

Mutagen/Mutagenitity: An agent that
causes a permanent genetic change in
a cell other than that which occurs
during normal growth. Mutagenicity is
the capacity of a chemical  or physical
agent to cause such permanent chang-
es.
N

National Ambient Air Quality Stan-
dards (NAAQS): Standards established
by  EPA that apply for outside  air
throughout the country. (See: criteria
pollutants, state implementation plans,
emissions trading.)
National Emissions  Standards For
Hazardous Air Pollutants (NESHAPS):
Emissions standards set by EPA for an
air pollutant not covered by NAAQS
that may cause an increase in fatali-
ties or in serious, irreversible, or inca-

-------
 26
 pacitating illness. Primary standards
 are designed to protect human health,
 secondary standards to protect public
 welfare (e.g.,  building facades,  visi-
 bility, crops, and domestic animals).

 National Estuary Program: A program
 established under the Clean Water Act
 Amendments of 1987 to  develop and
 implement conservation and manage-
 ment plans for protecting estuaries
 and restoring  and maintaining their
 chemical, physical, and biological in-
 tegrity, as well as controlling point and
 nonpoint pollution sources.
 National Interim Primary Drinking
 Water Regulations: Commonly referred
 to as NIPDWRs.

 National Municipal  Plan: A  policy
 created in 1984 by EPA and the states
 to bring all publicly owned treatment
 works (POTWs) into compliance with
 Clean Water Act requirements.
 National Oil and Hazardous Substanc-
 es Contingency Plan (NOHSCP/NCP):
 The federal regulation that guides
 determination of the sites to be correct-
 ed under both the Superfund program
 and the program to prevent or control
 spills into surface waters or elsewhere.
National Pollutant Discharge
tion System (NFDES): A provision of
the Clean Water Act which prohibits
discharge of pollutants into waters of
the  United  States  unless  a special
permit is issued by EPA, a state, or,
where  delegated,  a Native  American
tribal government.
National Priorities List (NFL): EPA's
list of the most serious uncontrolled or
abandoned hazardous waste sites iden-
tified for possible  long-term remedial
action  under Superfund. The  list is
based primarily on the  score  a  site
receives from the  Hazard  Ranking
System. EPA is required to update the
NFL at least once a year. A site must
be on the NPL to receive money from
the Trust Fund for remedial action.

National Response Team (NRT): Rep-
resentatives of 13  federal  agencies
that, as a team, coordinate federal
responses  to  nationally significant
incidents of pollution (an oil spill, a
major chemical release, or a Superfund
response action) and provide  advice
and technical assistance to the re-
sponding agency(ies) before and during
a response action.

National Response Center: The federal
operations center that receives notifica-
tions of all releases of oil and hazard-
ous substances into the environment;
open 24 hours a day, is operated by the
 U.S. Coast Guard, which evaluates all
 reports and notifies the appropriate
 agency.

 National Secondary Drinking  Water
 Rregulations: Commonly referred to as
 NSDWRs.

 Navigable Waters: Traditionally, wa-
 ters sufficiently deep  and wide  for
 navigation by all, or specified vessels;
 such waters in the United States come
 under  federal  jurisdiction and  are
 protected by certain provisions of the
 Clean Water Act.

 Necrosis:  Death of plant or  animal
 cells or tissues. In plants, necrosis can
 discolor stems or leaves or kill a plant
 entirely.

 Negotiations: (Under Superfund) After
 potentially responsible  parties  are
 identified  for  a site, EPA coordinates
 with them to  reach a settlement that
 will result in the PRP paying for or
 conducting the cleanup under EPA su-
 pervision. If negotiations fail, EPA can
 order the PRP to conduct the cleanup
 or EPA can pay for the cleanup 'using
 Superfund monies and then  sue to
 recover the costs.

 Nematocide: A chemical agent which is
 destructive to nematodes.

 Nephelometric Method of of measuring
 turbidity in a water sample by passing
 light through the sample and measur-
 ing the amount of the light that is de-
 flected.
 Netting: A concept in which all emis-
 sions sources in the same area that are
 owned or controlled by a single compa-
 ny  are  treated as one large  source,
 thereby allowing flexibility in control-
 ling individual sources in order to meet
 a single emissions standard. (See: bub-
ble)
Neutralization: Decreasing the acidity
 or alkalinity of a substance by adding
 alkaline or acidic  materials, respec-
tively.
New Source:  Any  stationary  source
built or modified after publication of
 final or proposed regulations that pre-
 scribe  a given  standard  of  perfor-
mance.
New Source Performance Standards
(NSPS> Uniform national  EPA air
emission and water effluent standards
which limit the  amount of pollution
 allowed from  new  sources or from
modified existing sources.
New Source Review (NSR> Clean Air
Act requirement that State Implemen-
tation Plans must include a permit re-
view that  applies to the construction
and operation  of new and  modified
stationary  sources in nonattainment
areas to assure  attainment of national
ambient air quality standards.

Nitrate: A compound containing nitro-
gen that can exist in the atmosphere
or  as a dissolved gas in  water and
which can have  harmful  effects on
humans and animals.  Nitrates  in wa-
ter can cause severe illness in infants
and domestic animals. A plant nutrient
and inorganic  fertilizer,  nitrate  is
found in septic systems, animal  feed
lots, agricultural  fertilizers,  manure,
industrial waste waters, sanitary land-
fills, and garbage dumps.

Nitric Oxide (NO):  A gas formed by
combustion under high temperature
and high pressure in an internal com-
bustion engine;  changes into nitrogen
dioxide in the  ambient air and  con-
tributes to photochemical smog.

Nitrification:  The process  whereby
ammonia in wastewater is  oxidized to
nitrite and then to nitrate by bacterial
or chemical reactions.

Nitrilotriacetic  Acid (NTA):  A com-
pound now  replacing phosphates in
detergents:

Nitrite: 1. An intermediate  in the pro-
cess of nitrification. 2. Nitrous oxide
salts used in food preservation

Nitrogen Dioxide (NOj): The  result of
nitric oxide combining with oxygen in
the atmosphere; major component of
photochemical smog.

Nitrogen Oxide (NO,): Product of com-
bustion from transportation  and sta-
tionary sources  and a major contribu-
tor to the formation of ozone  in the
troposphere and to acid deposition.

Nitrogenous Wastes: Animal  or vege-
table residues that contain significant
amounts of nitrogen.

Nitrophenola: Synthetic organopestic-
ides containing  carbon, hydrogen, ni-
trogen, and oxygen.

Noble Metal Chemically inactive metal
such as gold; does not corrode easily.

No Further Remedial Action Planned:
Determination made by EPA following
a preliminary assessment that a site
does not pose a significant risk  and so
requires  no  further  activity  under
CERCLA.

Noise: Product-level or product-volume
changes occurring during a test that
are not related  to a leak but may be
mistaken for one.

Non-Attainment Area: Area that does
not meet one or more of the National

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                                                                                                           27
Ambient Air Quality Standards for the
criteria pollutants designated in the
Clean Air Act.
Non-Binding Allocations of Responsi-
bility (NEAR): Process for EPA to pro-
pose a way for potentially responsible
parties to allocate costs among them-
selves.
Non-Community Water System: A pub-
lic water system that  is not a commu-
nity water system, e.g., the water sup-
ply at a camp site or national park.
.Non-Compliance  Coal: Any coal that
emits greqter than 3.0 pounds of sulfur
dioxide per million BTU when burned.
Also known as high-sulfur coal.

Non-Contact  Cooling  Water Water
used for cooling which does not come
into direct contact with any raw mate-
rial, product, byproduct, or waste.

Non-Conventional Pollutant: Any pol-
lutant not statutorily listed or which is
poorly understood  by  the  scientific
community.
Non-degradation:  An  environmental
policy which disallows any lowering of
naturally occurring quality regardless
of preestablished  health standards.
Nondischarging Treatment Plant: A
treatment  plant  that does not dis-
charge treated wastewater  into any
stream or river. Most are pond systems
that dispose of the total flow they re-
ceive by means of evaporation or perco-
lation to groundwater, or facilities-that
dispose of their effluent by recycling or
reuse (e.g., spray  irrigation or ground-
water discharge).
Nonfriable Asbestos-containing Materi-
als: Any material containing more than
one percent asbestos (as determined by
Polarized Light Microscopy) that, when
dry, cannot be crumbled, pulverized, or
reduced to powder by  hand pressure.
Non-ionizing Electromagnetic Radia-
tion: 1. Radiation that does not change
the structure of atoms but does, heat
tissue and may cause  harmful biologi-
cal effects. 2. Microwaves, radio waves,
and  low-frequency  electromagnetic
fields from high-voltage transmission
lines.

Non-Point Source: Diffuse  pollution
sources (i.e., without a single point of
origin or not introduced into a receiv-
ing stream from a specific outlet). The
pollutants are generally carried off the
land  by storm water. Common non-
point sources are  agriculture, forestry,
urban,  mining,  construction,  dams,
channels,  land  disposal, , saltwater
intrusion, and city streets.

Non-potable: Water that is unsafe or
unpalatable  to drink because it con-
tains . pollutants, contaminants, min-
erals, or infective agents.

Non-Road Emissions: Pollutants emit-
ted by combustion engines on farm and
construction equipment, gasoline-pow-
ered lawn and garden equipment, and
power boats and outboard motors.

Non-Transient Non-Community Water
System: A public water system that
regularly serves at  least 25 of the
same non-resident persons per day for
more than six months per year.
No Observable  Adverse Effect  Level
(NOAEL): From  long-term toxicologi-
cal studies of agricultural chemical
active ingredients,  levels which indi-
cate a safe, lifetime exposure level for
a given chemical.

Notice of Deficiency: An EPA request
to a facility owner or operator request-
ing additional information before  a
preliminary decision on a permit appli-
cation can be made.

Notice of Intent to Deny: Notification
by EPA of its preliminary intent to
deny a permit application.

No Till: Planting crops without prior
seedbed preparation, into an existing
cover crop, sod, or  crop residues, and
eliminating subsequent tillage  opera-
tions.
Nuclear Reactors and Support  Facili-
ties: Uranium mills, commercial power
reactors, fuel reprocessing plants, and
uranium enrichment facilities.
Nuclear Winter Prediction by some
scientists that smoke and debris rising
from massive fires of a nuclear war
could block sunlight for weeks or
months, cooling the earth's surface and
producing climate changes that could,
for example, negatively effect world ag-
ricultural and weather patterns.
Nuclide: An atom characterized by the
number of .protons, neturons, and ener-
gy in the nucleus.

Nutrient: Any substance assimilated
by living things that promotes growth.
The term is generally applied to ni-
trogen and phosphorus in wastewater,
but is also applied to other essential
and trace elements.

Nutrient Pollution: Contamination of
water resources by excessive inputs of
nutrients. In surface waters,  excess
algal production is a major concern.
Ocean Discharge Waiver A variance
from Clean Water Act requirements for
discharges into marine waters'.

Odor Threshold: The minimum odor of
a water sample that can just be detect-
ed after successive dilutions with odor-
less water. Also called threshold odor.

Offsets: A concept whereby emissions
from proposed new or modified station-
ary sources are balanced by reductions
from existing sources to stabilize total
emissions.  (See:  bubble,  emissions
trading, netting.)

Off-Site Facility: A hazardous waste
treatment,  storage  or disposal area
that is located away from the generat-
ing site.

Offstream Use: Water withdrawn from
surface or groundwater sources for use
at another place.

Oil  Desulfurization:   Widely  used
precombustion method  for  reducing
sulfur dioxide emissions from oil-burn-
ing power plants.  The oil  is treated
with hydrogen, which removes some of
the sulfur by forming hydrogen sulfide
gas.

Oil Fingerprinting: A method  that
identifies  sources  of  oil and allows
spills  to be traced to their source.

Oil Spill: An accidental or intentional
discharge of oil which reaches bodies of
water. Can be controlled by chemical
dispersion,  combustion,  mechanical
containment, and/or adsorption. Spills
from  tanks  and  pipelines can  also
occur  away from water bodies, contam-
inating the  soil,  getting into sewer
systems and threatening underground
water sources.

Oligotrophic Lakes: Deep clear lakes
with few nutrients, little organic mat-
ter and a high dissolved-oxygen level.

One-hit Model: A mathematical model
based on the biological theory that a
single "hit" of some minimum critical
amount of a carcinogen at a cellular
target such as DNA can start an irre-
versible series events leading to  a
tumor.

On-Scene Coordinator (OSO The pre-
designated EPA, Coast Guard, or De-
partment of Defense official who coor-
dinates and directs Superfund removal
actions or Clean Water Act oil-or haz-
ardous-spill  response actions.

On-Site Facility: A hazardous waste
treatment, storage or disposal  area
that is located on the generating site.

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28
Onboard Controls: Devices placed on
vehicles to capture gasoline vapor dur-
ing refueling and  route it to the en-
gines when the vehicle is starting so
that it can be efficiently burned.

Opacity: The amount of light obscured
by  particulate  pollution  in the air;
clear window glass has zero opacity, a
brick wall is 100 percent opaque. Opac-
ity is an indicator of changes in perfor-
mance of particulate  control systems.

Open Burning: Uncontrolled fire's in an
open dump.

Open Dump: An uncovered site used
for disposal of waste  without environ-
mental controls. (See: dump.)

Operable  Unit: Term for each of a
number of separate  activities  under-
taken  as  part  of a Superfund site
cleanup. A typical operable unit would
be removal of drums and tanks from
the surface of a site.  ,

Operating Conditions: Conditions spec-
ified in a RCRA permit  that  dictate
how an incinerator must operate as it
burns  different waste types. A trial
burn is used to identify operating con-
ditions needed to meet specified per-
formance standards.

Operation And Maintenance: 1. Activi-
ties conducted after a Superfund site
action is completed to ensure that the
action  is  effective. 2. Actions taken
after construction to assure that facili-
ties constructed to treat waste water
will  be properly operated and main-
tained to achieve normative efficiency
levels and prescribed effluent  limita-
tions in an optimum manner.  3. On-
going asbestos management plan in a
school or other public building, includ-
ing regular inspections, various meth-
ods of maintaining asbestos in place,
and removal when necessary.
Optimal Corrosion Control Treatment
An  erosion control  treatment that
minimizes the lead and copper concen-
trations at users' taps while also insur-
ing that the treatment does not cause
the water system to violate any nation-
al primary drinking water regulations.
Oral Tenacity: Ability of a pesticide to
cause injury when  ingested.

Organic  1.  Referring to or derived
from living organisms. 2. In chemistry,
any compound containing carbon.
Organic
                               Ani-
mal  or  plant-produced  substances
containing mainly carbon, hydrogen,
nitrogen, and oxygen.
Organic Matter: Carbonaceous waste
contained in  plant or animal matter
and originating from domestic or in-
dustrial sources.
Organism: Any form of animal or plant
life.

Organophosphates: Pesticides that con-
tain phosphorus; short-lived, but some
can be toxic when first applied.
Organotins: Chemical compounds used
in  anti-foulant paints to protect the
hulls of boats and ships, buoys,  and
pilings from marine organisms such as
barnacles.
Original  AHERA Inspection/Original
Inspection/Inspection: Examination of
school buildings  arranged  by Local
Education Agencies to identify asbesto-
s-containing-materials, evaluate their
condition, take samples of materials
suspected to contain asbestos;  per-
formed by EPA-accredited inspectors
Original   Generation  Point  Where
regulated medical or  other  material
first becomes waste.
Osmosis: The passage of a liquid from
a weak solution to a more concentrated
solution across a semipermeable mem-
brane that allows passage of the sol-
vent  (water) but not  the  dissolved
solids.
Outfall: The  place where effluent is
discharged into receiving waters.
Overburden:  Rock and soil  cleared
away before mining.
Overdraft: The pumping of water from
a  groundwater basin or aquifer in
excess of the supply flowing into the
basin; results in a depletion  or "min-
ing" of the groundwater in the basin.
(See: groundwater mining)
Overfire Air: Air forced into the top of
an incinerator  or boiler to  fan  the
flames.
Overflow Rate: One  of the guidelines
for design of the settling tanks  and
clarifers in a treatment plant; used by
plant operators to determine if tanks
and clarifiers are over-or under-used.
Overland  Flow:  A  land application
technique that cleanses waste water by
allowing it to flow over a sloped  sur-
face. As the water flows over the  sur-
face, contaminants are absorbed  and
the water is collected at the bottom of
the slope for reuse.
Oversized Regulated Medical Waste:
Medical waste that is too  large for
plastic bags or standard containers.
Overturn: One complete cycle of top to
bottom mixing of previously stratified
water masses. This phenomenon may
occur in spring or fall, or after storms,
and results in uniformity of chemical
and physical properties of water at all
depths.

Oxidant A substance containing oxy-
gen that reacts  chemically in air  to
produce a new substance; the primary
ingredient of photochemical smog.
Oxidation: The addition of oxygen that
breaks down organic waste or chemi-
cals such as cyanides, phenols, and
organic sulfur compounds in sewage by
bacterial and chemical means.

Oxidation Pond:  A man-made body  of
water in which waste is consumed by
bacteria, used most frequently with
other  waste-treatment processes;  a
sewage lagoon.

Oxidation-Reduction Potential:  The
electric potential required to transfer
electrons from one  compound or ele-
ment (the  oxidant) to another com-
pound,(the reductant); used as a quali-
tative measure of the state of oxidation
in water treatment systems.

Oxygenated Fuels: Gasoline which has
been blended with alcohols or ethers
that contain oxygen in order to reduce
carbon monoxide and other emissions.

Oxygenated Solvent An organic sol-
vent containing oxygen as part of the
molecular structure. Alcohols and keto-
nes are oxygenated compounds  often
used as paint solvents.

Ozone (Oj): Found in two layers of the
atmosphere, the  stratosphere and the
troposphere. In the stratosphere (the
atmospheric layer 7 to 10 miles or
more above the earth's surface) ozone
is  a natural form of oxygen that pro-
vides  a protective layer shielding the
earth from ultraviolet radiation. In the
troposphere (the layer extending up 7
to 10 miles from the earth's surface),
ozone is a chemical oxidant and major
component  of photochemical smog.  It
can seriously  impair the respiratory
system and is one of the most wide-
spread of all the criteria pollutants for
which the Clean Air Act required EPA
to set standards. Ozone in the tropo-
sphere is produced through complex
chemical reactions of nitrogen oxides,
which are among the primary pollut-
ants emitted by  combustion sources;
hydrocarbons, released into the atmo-
sphere through the combustion, han-
dling  and  processing  of  petroleum
products; and sunlight.
Ozonation/Ozonator: Application  of
ozone to water for disinfection or for
taste and odor control. The ozonator is
the device that does this.

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                                                                                                          29
Ozone Depletion: Destruction of the st-
ratospheric ozone layer which shields
the' earth from  ultraviolet radiation
harmful  to  life. This destruction  of
ozone is caused by the breakdown  of
certain chlorine and/or-bromJae  con-
taining   compounds   (chlorofluoro-
carbons or halons), which break down
when they reach the stratosphere and
then catalytically destroy ozone mole-
cules.

Ozone Hole:Thinning break in the stra-
tospheric ozone layer. Designation  of
amount of such depletion as an "ozone
hole" is made when detected amount of
depletion exceeds fifty percent. Sea-
sonal  ozone holes have been observed
over both the Antarctic region and the
Arctic region and part of Canada and
the  extreme  northeastern  United
States.   .

Ozone Layer The protective layer  in
the atmosphere, about 15 miles above
the ground, that absorbs some of the
sun's ultraviolet rays, thereby reducing
the amount  of  potentially  harmful
radiation that reaches the earth's sur-
face.
Packaging: The  assembly of one or
more containers and any other compo-
nents necessary to assure TniniTmiiti
compliance with a program's storage
and shipment packaging requirements.
Also, the containers, etc., involved.
Packed Bed Scrubber An air pollution
control device in which emissions pass
through alkaline water  to neutralize
hydrogen chloride gas.
Packed  Tower  A pollution control
device that forces dirty air through a
tower packed  with crushed rock or
wood chips while liquid is sprayed over
the packing material. The pollutants in
the air stream either dissolve or chemi-
cally react with the liquid.
Palatable Water Water, at a desirable
temperature, that  is  free from objec-
tionable tastes, odors, colors, and tur-
bidity.
Pandemic: Widespread throughout an
area, nation or the world.

Parameter  A variable, measurable
property whose value is a determinant
of die characteristics of a system; e.g.,
temperature, pressure, and density are
parameters of the atmosphere.
Paraquat: A standard herbicide used to
kill various types of crops, including
marijuana.

Part A Permit, Part B Permit: (See: In-
terim Permit Status.)

Parahall Flume: Device used  to mea-
sure the flow of water in an open chan-
nel.
Particle Count Results of a microscop-
ic examination of treated water with a
special "particle counter" that classifies
suspended particles  by number and
size.
Particulate Loading: The mass of part-
iculates per unit volume of air or wa-
ter.

Participation Rate: Portion of popula-
tion participating in a recycling pro-
grani.
Particulates: 1.  Fine liquid or solid
particles such as dust, smoke, mist,
fumes, or smog, found in air or emis-
sions. 2. Very small solids suspended
in water,; they can vary in size, shape,
density and electrical charge and can
be gathered together by coagulation
and fiocculation.

Partition Coefficient: Measure of the
sorption phenomenon, whereby a pesti-
cide is  divided between the soil and
water  phase; also referred to as ad-
sorption partition coefficient.
Parts Per Billion (ppbyParts Per Mil-
lion (ppm): Units commonly  used  to
express  contamination ratios, as  in
establishing the maximum permissible
amount, of a contaminant  in water,
.land, or air.
Pathogen*: Microorganisms that can
cause disease in other organisms or in
humans,  animals and plants (e.g.,
bacteria, viruses, or parasites) found in
sewage, in runoff from farms or rural
areas  populated  with domestic  and
wild animals, and in water used for
swimming. Fish and shellfish contami-
nated by pathogens,  or the contam-
inated water itself, can cause serious
illness.

Peak Electricity Demand: The maxi-
mum electricity used to meet the cool-
ing load of a building or buildings in a
given area.

Peak Levels: Levels of airborne pol-
lutant contaminants much higher than
average or occurring for short periods
of time in response to sudden releases.
Percent Saturatiuon: The amount of a
substance that is dissolved in a solu-
tion compared  to the amount that
could be dissolved in it.

Perched Water  Zone of unpressurized
water held above the  water table by
impermeable rock or sediment.

Percolating Water Water that passes
through rocks or soil under the force of
gravity.

Percolation: 1. The movement of water
downward and radially through subur-
face soil layers,  usually continuing
downward to ground water. Can also
involve upward  movement of water. 2.
Slow seepage of water through a filter.
Performance Data (for incinerators):
Information collected, during a trial
burn, on concentrations of designated
organic compounds  and  pollutants
found in incinerator emissions.  Data
analysis must show that the incinera-
tor meets performance standards un-
der operating conditions specified  in
the RCRA permit. (See: trial burn; per-
formance standards.)
Performance Standards: 1. Regulatory
requirements limiting the concentra-
tions of designated organic compounds,
particulate matter, and hydrogen chlo-
ride in emissions from incinerators. 2.
Operating  standards  established  by
EPA for various permitted  pollution
control systems, asbestos inspections,
and various program  operations and
maintenance requirements.
Periphyton;  Microscopic  underwater
plants and animals that are firmly at-
tached solid surfaces  such as rocks,.
logs, pilings, and other structures.

Permeability: The rate at which liquids
pass through soil or other materials in
a specified direction.
Permissible Dose: The dose of a chemi-
cal that may be  received by an individ-
ual  without the  expectation  of  a
sinificantly harmful result.
Permit: An  authorization, license,  or
equivalent control document issued by
EPA or an approved state  agency  to
implement the requirements of  an
environmental regulation; e.g., a per-
mit to operate a wastewater treatment
plant or to operate a facility that may
generate harmful emissions.

Persistence: Refers to the  length  of
time a compound stays in the environ-
ment, once  introduced. A  compound
may persist for less than a second or
indefinitely.

Persistent Pesticides:  Pesticides that
do  not  break  down   chemically  or

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30
break down very slowly and remain in
the environment after a growing sea-
son.
Personal  Air Samples: Air  samples
taken with a pump directly attached to
the worker with the collecting filter
and cassette placed in the  worker's
breathing zone (required under OSHA
asbestos standards and EPA worker
protection rule).

Pest: An insect, rodent, nematode, fun-
gus, weed or other form of terrestrial
or aquatic plant or animal life that is
injurious to health or the environment.

Pesticide: Substances or mixture there-
of intended for preventing, destroying,
repelling, or mitigating any pest. Also,
any substance or mixture intended for
use as a plant regulator, defoliant, or
desiccant.

Pesticide  Tolerance: The amount of
pesticide residue allowed by law to
remain in or on a harvested crop. EPA
sets these levels well below the point
where the compounds might be harm-
ful to consumers.
Petroleum  Derivatives:  Chemicals
formed when gasoline breaks  down in
contact with ground water.

pH; An expression of the intensity of
the basic or acid condition of  a, liquid;
may range from 0 to 14, where 0 is the
most  acid and 7  is  neutral.  Natural
waters usually have a pH between 6.5
and 8.5.
Pharmakinetica: The dynamic behavior
of chemicals inside biological systems,
including uptake, distribution, metab-
olism, and excretion.
Phenolphthalein Alkalinity The alka-
linity  in a water sample measured by
the amount of standard acid needed to
lower thge pH to a level of 8.3 as indi-
cated  by the change of  color of the
phenolphthalein from pink to  clear.

Phenols: Organic compounds  that are
byproducts of petroleum refining, tan-
ning, and textile, dye, and resin manu-
facturing. Low concentrations cause
taste  and  odor  problems  in water;
higher concentrations can kill aquatic
life and humans.
Phosphates:  Certain chemical  com-
pounds containing phosphorus.
Phosphogypsum Piles (stacks): Princi-
pal byproduct generated in production
of phosphoric acid  from phosphate
rock. These piles may generate radio-
active radon gas.

Phosphorous  Plantar Facilities using
electric furnaces to produce elemental
phosphorous for commercial use, such
as high grade phosphoric acid, phos-
phate-based  detergent, and  organic
chemicals use.   .

Phosphorus: An essential chemical food
element  that  can contribute  to the
eutrophication of lakes and other wa-
ter bodies. Increased phosphorus levels
result  from  discharge   of   phosp-
horus-containing materials into surface
waters.

Photochemical Oxidants: Air pollutants
formed by the action of sunlight on ox-
ides of nitrogen and hydrocarbons.

Photochemical  Smog:  Air pollution
caused by chemical reactions of various
pollutants   emitted   from  different
sources.

Photosynthesis:  The manufacture by
plants of carbohydrates  and oxygen
from carbon dioxide mediated by chlo-
rophyll in the presence if sunlight.

Physical and Chemical Treatment: Pro-
cesses generally used in large-scale
wastewater treatment facilities. Physi-
cal processes may include air-stripping
or filtration. Chemical treatment in-
cludes coagulation,  chlorination, or
ozonation. The term can also refer to
treatment of toxic materials in surface
and ground waters, oil spills, and some
methods of  dealing  with hazardous
materials on or in the ground.

Phytoplankton: That  portion  of the
plankton community comprised of tiny
plants, e.g., algae, diatoms.
Phytotozie Harmful to plants.
Picocuries Per Liter pCVL>. A unit of
measure for levels of radon gas.
Pilot  Tests:  Testing  a cleanup tech-
nology under actual site conditions to
identify potential problems prior to
full-scale implementation.

Plankton: Tiny  plants and animals
that live in water.

Plasma-arc  Reactor. An  incinerator
that operates at extremely high tem-
peratures; treats highly toxic wastes
that do not burn easily.
Plasmid: A circular piece of DNA that
exists apart from the chromosome and
replicates independently of it. Bacterial
plasmids carry information that ren-
ders the bacteria resistant to antibi-
otics. Plasmids are'often used in genet-
ic engineering to carry desired genes
into organisms.
Plastics: Non-metallic  chemoreactive
compounds molded into rigid or pliable
construction materials, fabrics, etc.
 Plate Tower Scrubber An air pollution
 control device that neutralizes hydro-
 gen chloride gas by bubbling alkaline
 water through  holes  in a series  of
 metal plates.

 Plug Flow: Type of flow that occurs in
 tanks, basins, or reactors when a slug
 of water moves  through without ever
 dispersing or mixing with the  rest of
 the water flowing through.

 Plugging: Act or process of stopping
 the flow of water, oil, or gas into or out
 of a formation through a borehole  or
 well penetrating that formation.

 Plume: 1. A visible or measurable dis-
 charge of a contaminant from a given
 point of origin. Can be visible or ther-
 mal in water, or visible in the  air as,
 for example, a plume of smoke. 2 The
 area of radiation leaking from a dam-
 aged reactor. 3. Area downwind within
 which a release could be dangerous for
 those exposed to leaking fumes.

 Plutonium: A radioactive metallic ele-
 ment chemically similar to uranium.

 PM-10: A standard for measuring the
 amount of solid or liquid matter sus-
 pended in  the  atmosphere, i.e. the
'amount of particulate matter over 10
 micrometers in diameter; smaller PM-
 10  particles penetrate to the deeper
 portions of the lung, affecting sensitive
 population groups such as children and
 individuals with respiratory ailments.

 Point of Disinfectant Application: The
 point where disinfectant is applied and
 water downstream of that point is not
 subject to recontamination by surface
 water runoff.

 Point-of-Entry Treatment Device:  A
 treatment device 'applied to the drink-
 ing water entering a house or building
 to  reduce  the  contaminants  in the
 water distributed throughout the house
 or building.

 Point-of Use Treatment Device: Treat-
 ment device applied to a single tap to
 reduce contaminants in  the drinking
 water at the one faucet

 Point Source: A  stationary location or
 fixed facility from which pollutants are
 discharged;  any  single  identifiable
 source of pollution, e.g., a pipe, ditch,
 ship, ore pit, factory smokestack.

 Pollen: The fertilizing element of flow-
 ering plants; background air pollutant.

 Pollutant: Generally, any substance in-
 troduced into the environment that ad-
 versely affects the usefulness of a re-
 source.

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                                                                                                         31
Pollution Prevention; The active pro-
cess of identifying  areas, processes,
and activities which create excessive
waste byproducts or pollutants for the
purpose of substitution, alteration, or
elimination of the process to prevent
waste and pollutant generation.

Pollutant Standard Index (PSD: Mea-
sure of adverse health effects  of air
pollution levels in major cities.
Pollution:  Generally, the presence of
matter or  energy whose nature, loca-
tion, or quantity produces undesired
environmental effects. Under the Clean
Water Act, for example, the term is
defined as the manmade or man-in-
duced alteration of the physical, biolog-
ical, chemical, and radiological integ-
rity of water. ,

Polonium:  A radioactive element that
occurs in pitchblende and other urani-
um-containing ores.
Polyelectrolytea: Synthetic chemicals
that help solids to clump during sew-
age treatment.
Polymer: Basic molecular ingredients
in plastic.
Polyvinyl  Chloride  (PVC): A tough,
environmentally indestructible plastic
that releases hydrochloric acid when
burned.
Population: A group of interbreeding
organisms  occupying  a  particular
space; the  number of humans or other
living creatures in a designated area.

Population at Riak: A population sub-
group that is more likely to be exposed
to a pollutant, or is more sensitive to
the pollutant, than is the general popu-
lation.
Porosity. Degree to which noil, gravel,
sediment,  or rock is permeated with
pores or cavities through which water
or air «•*" move.
Poetchlorination: Addition of chlorine
to plant effluent for disinfectant pur-
poses after the effluent has been treat-
ed.
Poet-Closure: Time period following the
shutdown  of a waste management or
manufacturing facility; for monitoring
purposes,  often considered to, be 30
years.
Post-Consumer  Recycling: Reuse  of
materials  generated from residential
and consumer waste,  e.g..  converting
wastepaper from offices into corrugat-
ed boxes or newsprint.
Potable Water Water that is safe for
drinking and cooking.

Potentially Responsible Party (PRP>.
Any individual or company-including
owners, operators,  transporters  or
generators-potentially responsible for,
or contributing to a spill or other con-
tamination at a Superfund site. When-
ever possible, through administrative
and legal actions, GPA requires PRPs
to clean up hazardous sites they have
contaminated.

Potentiation: The ability of one chemi-
cal to  increase the effect of another
chemical.
Prechlorination: The addition of chlo-
rine at the headworks of a treatment
plant prior to other treatment process-
es. Done mainly for disinfection and
control of  tastes, odors, and aquatic
growths, and to aid in coagulation and
settling,

Precipitate: A solid that separates from
a solution.

Precipitation: Removal of hazardous
solids from liquid waste to permit safe
disposal;  removal of  particles from
airborne emissions.
Precipitator. Pollution control device
that collects  particles  from  an  air
stream.

Precursor: In photochemistry, a com-
pound antecedent to a volatile organic
compound (VOC). Precursors react in
sunlight to form ozone or other photo-
chemical oxidants.
Preliminary Assessment: The process
of collecting and reviewing available
information about a known or suspect-
ed waste site or release.
Prescriptive: Water rights which are
acquired by diverting water and put-
ting it to use in accordance with speci-
fied procedures, e.g., filing a request
with a state  agency to use unused
water in a stream, river, or lake..
Pressure Sewers: A system of pipes in
which  water, wastewater,  or other
liquid is pumped to a higher elevation.

Pretreatinent: Processes used to re-
duce, eliminate, or alter the nature of
wastewater pollutants  from non-dom-
estic sources before  they are dis-
charged into publicly owned treatment
works (POTWs).

Prevalent Level Samples: Air samples
taken under normal conditions (also
known as ambient background sam-
ples).
 Prevalent Levels:  Levels of airborne
 contaminant occurring under normal
 conditions.

 Prevention of Significant Deterioration
 (PSD):  EPA program in  which state
 and/or federal permits are required in
 order to restrict emissions from new or
 modified sources in places  where air
 quality already meets or exceeds pri-
 mary and secondary ambient air quali-
 ty standards.

 Primacy: Having the primary responsi-
 bility for administering and enforcing
 regulations.
 Primary Drinking Water Regulation:
 Applies, to public water systems and
 specifies a contaminant level, which, in
 the judgment of the EPA Administra-
 tor,  will not adversely affect human
 health.

 Primary Standards: National ambient
 air quality standards designed to pro-
. tect human health with an adequate
 margin for safety. (See National Ambi-
 ent Air Quality Standards, secondary
 standards)
 Primary Waste Treatment:  First steps
 in wastewater treatment; screens and
 sedimentation tanks are used to re-
 move most materials that float or will
 settle.  Primary treatment removes
 about 30 percent of carbonaceous bio-
 chemical oxygen demand from domes-
 tic sewage.

 Principal Organic Hazardous Constitu-
 ents (POHCa): Hazardous compounds
 monitored during an incinerator's trial
 burn, selected for high concentration in
 the waste feed and difficulty of com-
 bustion.
 Prior  Appropriation:  A  doctrine  of
 water law that allocates the rights to
 use water on a first-come, first-served
 basis.

 Probability  of Detection:  The likeli-
 hood, expressed as a percentage, that
 a test method will correctly identify a
 leaking tank.
 Process Variable: A physical or chemi-
 cal quantity which is usually measured
 and controlled in  the operation of a
 water treatment plant or  industrial
 plant.

 Process  Verification:  Verifying  that
 process raw materials, water usage,
 waste treatment processes,  production
 rate and other facts relative to quanti-
 ty and quality of pollutants contained
 in. discharges  are substantially  de-
 scribed in the permit application and
 the issued permit.

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 32
 Process Waste-water Any water that
 comes into contact with any raw mate-
 rial, product, byproduct, or waste.

 Process Weight:  Total weight of all
 materials, including fuel, used in a ma-
 nufacturing process; used to calculate
 the allowable  particulate  emission
 rate.

 Product Level: The level of a product
 in a storage tank.

, Product Water Water that has passed
 through a water treatment plant and
 is ready to be delivered to consumers.

 Products of Incomplete Combustion
 (PICs): Organic compounds formed by
 combustion.   Usually  generated  in
 small  amounts and sometimes toxic,
 PICs are heat-altered  versions of the
 original material fed  into the incin-
 erator  (e.g.,  charcoal  is  a P.C.  from
 burning wood).

 Propellent: Liquid in a self-pressurized
 pesticide product that expels the active
 ingredient from its container.

 Proposed Plan: A plan  for a site clean-
 up that is available to the public for
 comment.

 Proteins: Complex nitrogenous organic
 compounds  of high molecular weight
 made  of amino  acids; essential for
 growth and repair of animal tissue.
 Many,  but  not all,  proteins are en-
 zymes.

 Protocol: A  series of formal steps for
 conducting a test.

 Protoplast:  A  membrane-bound  cell
 from which the outer wall has been
 partially or completely removed. The
 term often is applied to plant cells.
 Protozoa: One-celled animala that are
 larger and more complex than bacteria.
 May cause disease.
 Public Comment Period: The time al-
 lowed for the public  to  express  its
 views and concerns regarding an  ac-
 tion by EPA (e.g., a Federal Register
 Notice  of proposed rule-making,  a
 public notice of a draft permit, or a No-
 tice of Intent to Deny).
 Public Hearing: A formal meeting at
 which EPA officials hear  the public's
 views and  concerns about an EPA
 action or proposal. EPA is required to
 consider such comments when evalu-
 ating its actions. Public hearings must
 be held upon request during the public
 comment period.
 Public Notice: 1. Notification by EPA
 informing the public of Agency actions
 such as the issuance of a draft permit
 or scheduling of a  hearing. EPA is
required to ensure proper public notice,
including  publication in newspapers
and broadcast media.- 2. In the  safe
drinking water program, water suppli-
ers are required to publish and broad-
cast notices when pollution problems
are discovered.
Public Water System: A system  that
provides piped water for human  con-
sumption  to at least 15  service  con-
nections or regularly serves 25 indi-
viduals.
Publicly Owned Treatment Works:  A
waste-treatment works  owned by a
state, unit of local  government, or
Indian tribe, usually designed to treat
domestic waste waters. .
Pumping Station:  Mechanical devices
installed in sewer or. water systems or
other liquid-carrying pipelines to move
the liquids to a higher level.
Putrefaction: Biological decomposition
of organic matter; associated  with
anaerobic  conditions.
Putreacible: Able to rot quickly enough
to cause odors and attract flies.
Pyrolyms:  Decomposition of a chemical
by extreme heat.
Quality Assurance/Quality Control:  A
system of procedures, checks, audits,
and corrective actions to ensure that
all EPA research design  and perfor-
mance, environmental monitoring and
sampling,  and  other technical  and
reporting activities are of the highest
achievable quality.
Quench Tank   A water-filled tank
used to cool incinerator residues or hot
materials during industrial processes.
Radiation:  Transmission  of  energy
though  space  or  any medium. Also
known as radiant energy.
Radiation Standards: Regulations that
set maximum exposure limits for pro-
tection of the public from radioactive
materials.
Radio Frequency Radiation: (See Non-
ionizing Radiation.)
Radioactive   Decay:   Spontaneous
change  in  an atom by emission of
charged particles and/or  gamma rays;
also known as radioactive  disintegra-
tion and radioactivity.
Radioactive Substances: Substances
that emit ionizing radiation.

Radioisotopes: Chemical variants of an
element  with potentially oncogenic,
teratogenic, and mutagenic effects on
the human body.

Radionuclide:   Radioactive  particle,
man-made  or natural, with a. distinct
atomic weight  number. Can have a
long life as soil or water pollutants.

Radius of  Vulnerability  Zone:   The
maximum distance from  the point of
release of  a hazardous substance  in
which the airborne concentration could
reach the level of concern under spec-
ified weather conditions.

Radon:   A colorless naturally occur-
ring, radioactive, inert  gas formed by
radioactive decay of radium atoms  in
soil or rocks,

Radon   Daughters/Radon  Progeny:
Short-lived radioactive decay  products
of radon  that decay into longer-lived
lead isotopes that can attach them-
selves to airborne dust and other parti-
cles and, if inhaled, damage the linings
of the lungs.

Radon Decay Products: A term used to
refer collectively to the  immediate
products  of the radon decay chain.
These include Po-218, Pb-214, Bi-214,
and  Po-214, which have an average
combined half-life of about 30 minutes.

Rasp: A  machine that grinds waste
into a manageable material and helps
prevent odor.

Raw Sewage: Untreated wastewater
and its contents.

Raw Water Intake water prior to any
treatment or use.

Reaeration: Introduction of air into the
lower layers of a reservoir. As the air
bubbles form and rise through the wa-
ter, the oxygen dissolves into the water
and replenishes the dissolved oxygen.
The rising bubbles also cause the lower
waters to rise to the surface where
they take on oxygen from the atmosph-
ere.

Reasonable Further Progress: Annual
incremental reductions in air pollutant
emissions as reflected in a State Imple-
mentation Plan that EPA deems suffi-
cient to provide for the attainment of
the  applicable national ambient  air
quality standards by the statutory dea-
dline.
Reasonable Maximum Exposure: The
maTJTrmm exposure reasonably expect-
ed to occur in a population.

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                                                                                                          33
Reasonably  Available  Control  Mea-
sures (RACM): A broadly defined term
referring to technological and other
measures for pollution control.

Reasonably Available Control Technol-
ogy (RACT): Control technology that is
reasonably available and both techno-
logically  and  economically  feasible.
Usually applied to existing sources in
nonattainment areas; in most cases is
less stringent than new source perfor-
mance standards.

Recarbonization:  Process in  which
carbon dioxide is bubbled into water
being treated to lower the pH.
Receiving Waters: A river, lake, ocean,
stream,  or  other watercourse  into
which wastewater or treated effluent is
discharged.

Recharge: The process by which water
is added to a zone of saturation, usual-
ly by percolation from the soil surface,
e.g., the recharge of an aquifer.

Recharge Area: A land area in which
water reaches the zone of saturation
from surface infiltration, e.g., where
rainwater  soaks through the earth to
reach an aquifer.

Recharge Rate: The quantity of water
per unit of time that replenishes or
refills an aquifer.

Reclamation: (In recycling) Restoration
of materials found in the waste stream
to  a beneficial use which may be for
purposes other than the original use.

Recombinant Bacteria: A microorgan-
ism whose genetic makeup has been
altered by deliberate introduction of
new genetic elements. The offspring of
these altered  bacteria  also contain
these new genetic elements:, i.e. they
"breed true."

Recombinant DNA: The new DNA that
is formed by combining pieces of DNA
from different organisms or cells.
Level (RMCL): The maximum level of
a contaminant  in drinking water  at
which no known or anticipated adverse
affect on human health would occur,
and that includes an adequate margin
of safety.  Recommended  levels are
nonenforceable  health  goals.  (See:
maximum contaminant level.)

Reconstructed Source:   Facility  in
which components are replaced to such
an extent that the fixed capital cost of
the new components exceed 50 percent
of the capital cost of constructing a
comparable brand-new facility. New-
 source performance standards may be
 applied to sources reconstructed after
 the proposal of the standard if it is
 technologically and economically feasi-
 ble to meet the standard.
 Record of Decision  (ROD): A  public
 document that explains which cleanup
 alternative(s) will be used at National
 Priorities  List  sites  where,  under
 CERCLA, Trust Funds  pay for the
 cleanup.
 Recovery Rate:  Percentage of usable
 recycled materials that have been re-
 moved from the total  amount of mu-
 nicipal solid waste generated in a spe-
 cific area or by a specific business.
 Recycle/Reuse: Minimizing waste gen-
 eration by recovering and reprocessing
 usable products that might otherwise
 become waste  (.i.e.  recycling of alu-
 minum cans, paper, and bottles, etc.).
 Red Bag Waste: (See: infectious waste.)
 Red Border: An EPA document under-
 going review before being submitted
 for final management decision-making.
 "Red Tide: A proliferation of a marine
 plankton toxic often fatal to fish, per-
 haps  stimulated by the  addition of
 nutrients. A tide can be red, green, or
 brown, depending on the coloration of
 the plankton.
 Reduction:  The addition of hydrogen,
 removal of oxygen, or addition of elect-
 rons to an element or compound.
 Reentry Interval: The period of time
 immediately following the application
 of a pesticide during which unprotected
 workers should not enter a field.
 Reference Dose (RfD):  The concentra-
 tion  of a chemical  known to cause
 health problems; also referred to as the
 ADI, or acceptable daily intake.
 Reformulated Gasoline: Gasoline with
 a different composition from conven-
 tional gasoline (e.g., lower aromatics
 content) that cuts air pollutants.
 Roftioling Emissions:  Emissions re-
 leased during vehicle refueling.
 Refuse Reclamation:  Conversion of
 solid waste into useful products, e.g.,
 composting organic wastes to make soil
 conditioners or separating aluminum
 and other metals for recycling.
 Refuse: (See: solid waste.)
. Regeneration: Manipulation of cells to
 cause them to  develop  into  whole
 plants.
Regional Response Team (RRT): Repre-
sentatives of federal, local, and state
agencies who may assist in coordina-
tion of activities at the request of the
On-Scene Coordinator before and dur-
ing a- significant pollution  incident
such as an  oil spill, major chemical
release, or a Superfund response.

Registrant: Any manufacturer or for-
mula tor who obtains registration for a
pesticide active ingredient or product.

Registration: Formal listing with EPA
of a new pesticide before it can be sold
or distributed. Under the Federal In-
secticide, Fungicide, and  Rodenticide
Act. EPA is responsible for registration
(pre-market licensing) of pesticides on
the basis of data demonstrating no un-
reasonable adverse effects on human
health or  the environment when ap-
plied according to approved label direc-
tions.

Registration  Standards:   Published
documents which include summary re-
views of the data available on a pest-
icide's active ingredient, data gaps, and
the -Agency's existing regulatory posi-
tion on the pesticide.
Regulated Asbestos-Containing Materi-
al (RACM>. Friable asbestos material
or nonfriable ACM that will be or has
been  subjected to sanding, grinding,
cutting, or abrading or has crumbled,
or been pulverized or reduced to pow-
der in the course of demolition or ren-
ovation operations.

Regulated Medical Waste: Under the
Medical Waste Tracking Act of  1988,
any solid waste generated in the diag-
nosis, treatment, or immunization of
human beings or animals, in research
pertaining thereto, or in the production
or testing of biologicals. Included are
cultures  and stocks  of infectious
agents; human blood and blood prod-
ucts; human pathological body wastes
from surgery and autopsy; contaminat-
ed animal carcasses from medical re-
search; waste from patients with com-
municable diseases; and all used sharp
implements, such as needles and scal-
pels, etc.,  and certain unused sharps.
(See; treated medical waste; untreated
medical  waste;  destroyed  medical
waste.)
Release: Any spilling, leaking, pump-
ing, pouring, emitting,  emptying, dis-
charging, injecting, escaping, leaching,
dumping, or disposing into the environ-
ment of a hazardous or toxic chemical
or extremely hazardous substance.

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34
Remedial Action (RA): The actual cons-
truction or implementation phase of a
Super-fund site cleanup that follows
remedial design.

Remedial Design: A phase of remedial
action that follows the remedial inves-
tigation/feasibility study and includes
development of engineering drawings
and specifications for a  site cleanup.

Remedial Investigation: An  in-depth
study designed to gather data needed
to determine the nature and extent of
contamination at a  Superfund site,
establish site cleanup criteria, identify
preliminary alternatives for remedial
action, and support technical and cost
analyses of alternatives. The remedial
investigation is usually done with the
feasibility study. Together they are
usually referred to as the "RI/FS".

Remedial Project Manager (RPM): The
EPA or state  official responsible  for
overseeing on-site remedial action.

Remedial Response: Long-term action
that stops or substantially reduces a
release or threat of a release of hazard-
ous substances that is serious but not
an immediate threat to  public health.

Remediation:   1. Cleanup  or other
methods used  to remove or contain a
toxic spill or hazardous materials from
a Superfund site; 2. for the Asbestos
Hazard Emergency Response program,
abatement methods including  evalu-
ation, repair, enclosure, encapsulation,
or removal of greater than 3 linear feet
or square feet of asbestos-containing
materials from a building.
Remote Sensing:  The  collection and
interpretation of information about an
object without physical contact with
the object; e.g., satellite imaging and
aerial photograph.
Removal Action: Short-term immediate
actions taken  to address releases  of
hazardous  substances  that require
expedited response. (See: cleanup.)

Repeat Compliance Period: Any subse-
quent  compliance  period  after the
initial one.

Reportable Quantity (RQ): Quantity of
a hazardous substance that triggers re-
ports under CERCLA. If a substance
exceeds its RQ, the release must be
reported to  the National Response
Center, the  SERC, and ^immunity
emergency coordinators for areas likely
to be affected.
Repowering: Rebuilding and replacing
major components  of a power plant
instead of building a new one.
Representative  Sample:  A portion of
material or water that  is as nearly
identifies! in content and consistency
as possible to that in'the larger body of
material or water being sampled.

Reregistration: The reevaluation  and
relicensing of existing pesticides origi-
nally registered prior to current scien-
tific and regulatory standards.  EPA
reregisters pesticides through its Reg-
istration Standards Program. .

Reserve  Capacity: Extra  treatment
capacity built into solid waste   and
wastewater treatment plants and in-
terceptor sewers to accommodate flow
increases  due to  future population
growth.

Reservoir: Any natural  or artificial
holding area used to store, regulate, or
control water.

Residual: Amount of a pollutant re-
maining in the environment after a
natural or technological process  has
taken place, e.g., the sludge remaining
after initial wastewater treatment, or
particulates remaining in air after it
passes through  a scrubbing or other
process.

Residual Risk: The extent of health
risk from  air pollutants  remaining
after application of the Maximum A-
chievable Control Technology (MACT).

Residue:  The dry solids  remaining
after the evaporation of a sample of
water or sludge.
Resistance: For plants  and animals,
the ability to withstand poor environ-
mental conditions or attacks by chemi-
cals or disease.  May be inborn or ac-
quired.
Reaource Recovery: The process of
obtaining matter or energy from mate-
rials formerly discarded.
Response Action:  1. Generic term for
actions taken in response to actual or
potential health-threatening environ-
mental events such as spills, sudden
releases,   and  asbestos   abate-
menl/manageinent problems;  2.  A
CERCLA-authorized action  involving
either a short-term removal action or a
long-term removal response. This may
include but is not limited to: removing
hazardous materials from a site to an
EPA-approved hazardous waste facility
for treatment, containment or treating
the waste on-site, identifying and re-
moving the  sources of ground-water
contamination  and halting further
migration of contaminants; 3. Any of
the following actions taken in school
buildings in response to AHERA to
reduce the risk of exposure to asbestos:
removal,  encapsulation,  enclosure,
repair,  and operations  and ' mainte-
nance. (See: cleanup)

Responsiveness Summary: A summary
of oral and/or written public comments
received by EPA during a comment
period on key EPA documents,  and
EPA's response to those comments.

Restoration: Measures taken to return
a site to pre-violation conditions.

Restricted Use:  A pesticide may be
classified (under FIFRA regulations)
for  restricted  use  if the it  requires
special handling because of its toxicity,
and, if so, it may be applied only by
trained, certified applicators or those
under their direct supervision.

Restriction Enzymes:  Enzymes that
recognize  specific regions  of a long
DNA molecule and cut it at those
points.

Retrofit: Addition of a pollution control
device on an existing facility without
making major changes to the generat-
ing plant.

Reuse: Using a product or component
of municipal solid waste in its original
form more than once,  e.g., refilling a
glass bottle that has been returned or
using a coffee can to  hold nuts  and
bolts.

Reverse Osmosis: A treatment process
used in water systems by adding pres-
sure to force water through a semi-
permeable membrane. Reverse osmosis
removes most drinking water contami-
nants. Also used in wastewater treat-
ment.  Large-scale  reverse  osmosis
plants are being developed.

Reversible Effect: An  effect which is
not permanent;   especially adverse
effects which diminish when exposure
to a toxic chemical stops.

Ribonucleic  Acid (RNA): A molecule
that carries the genetic message from
DNA to a cellular protein-producing
mechanisms.

Rill: A small channel eroded into the
soil by surface runoff; can be easily
smoothed out or  oblitrated by normal
tillage.

Ringlemann Chart: A series of shaded
illustrations used to measure the opac-
ity of air pollution emissions, ranging
from light grey through black; used to
set and enforce emissions standards.

Riparian Habitat:  Areas adjacent to
rivers and streams with a high densi-
ty, diversity, and productivity of plant
and animal species relative to nearby
uplands.

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                                                                                                            35
Riparian Rights: Entitlement of a land
owner to certain uses of water on or
bordering his property,  including the
right to prevent diversion or misuse of
upstream waters. Generally a matter
of state law.
Risk: A measure of the probability that
damage to life, health, property, and/or
the environment will occur as a result
of a given hazard.
Risk  Assessment;  Qualitative   and
quantitative  evaluation  of  the  risk
posed  to  human health  and/or the
environment by the actual or potential
presence and/or use of specific pollut-
ants.
Risk-baaed Targeting: The direction of
resources to those  areas that  have
been identified as having the highest
potential or actual  adverse effect on
human health and/or the environment.

Risk Characterization: The last step in
the risk  assessment process; charac-
terizes  the  potenetial   for  adverse
health effects and evaluates the degree
of uncertainty involved.
Risk Communication: The exchange of
information about health or environ-
mental risks among risk assessors and
managers,  the  general  public, news
media, interest groups, etc.
Risk Estimate: A  description of the
probability that organisms exposed to
a specific dose of a chemical or other
pollutant will develop an adverse re-
sponse, e.g., cancer.
Risk Factor Characteristics (e.g., race,
sex, age,  obesity)  or variables  (e.g.,
smoking, occupational exposure level)
associated with increased probability of
a toxic effect.
Risk  Management:  The  process of
evaluating and  selecting alternative
regulatory and non-regulatory respons-
es to risk. The selection process neces-
sarily  requires the  consideration of
legal, economic, and behavioral factors.

Risk-Specific DOM: The dose associated
with a specified risk level.

River Basin: The land area drained by
a river and its tributaries.
Rodenticide; A chemical or agent used
to destroy rats or other rodent peats, or
to prevent them from damaging food,
crops, etc.
Rotary Kiln Incinerator. An incinerator
with a rotating combustion chamber
that  keeps waste  moving,  thereby
allowing it to vaporize for easier burn-
ing.
Rough Fish: Fish not prized for eating,
such as gar and • suckers. Most are
more tolerant of changing environmen-
tal conditions than game species.

Route of Exposure: The  avenue  by
which a chemical  comes into contact
with an  organism,  e.g.,  inhalation,
ingestion, dermal contact, injection.

Rubbish:  Solid waste,  excluding food
waste and ashes, from homes, institu-
tions, and work-places.

Run-Off.  That part of precipitation,
snow melt,  or irrigation  water that
runs off the land into streams or other
surface-water. It can carry pollutants
from the  air and land into receiving
waters.

Running Losses: Evaporation of motor
vehicle fuels from the fuel tank while
the vehicle is in use.
Sacrifical Anode: An easily corroded
material deliberately installed  in  a
pipe or intake to give it up to corrosion
while  the  rest  of the water supply
facility remains relatively corrosion-
free.
Safe:  Condition of  exposure under
which there  is a practical certrainty
that no harm will result to exposed
indiviuals.

Safener A chemical added to a pesti-
cide to keep it from injuring plants.
Safe Water Water that does not con-
tain harmful bacteria, toxic materials,
or chemicals, and is considered safe for
.drinking even if it may have taste,
odor, color, and  certain mineral prob-
lems.
Safe  Yield:  The annual  amount of
water that can be taken from a source
or supply over a period of years with-
out depleting that source beyond its
ability to be replenished naturally in
"wet years."
Salinity: The percentage of salt in
water.

Salt Water Intrusion: The invasion of
fresh surface or ground water by salt
water. If it comes from the ocean  it
may be called sea water intrusion.

Salts: Minerals that water picks up as
it passes through the air,  over and
under the ground, or from households
and industry.

Salvage: The utilization of waste mate-
rials.
Sanctions: Actions taken by the federal
government for failure to plan or im-
plement  a State Improvement  Plan
(SIP).  Such action may  be include
withholding of highway funds and a
ban on construction of new sources of
potential pollution.

Sand Filters:  Devices  that remove
some suspended solids from sewage.
Air and bacteria decompose additional
wastes filtering through the sand so
that cleaner water drains from the bed.

Sanitary Landfill: (See: landfills.)

Sanitary Sewers: Underground pipes
that carry off only domestic or indus-
trial waste, not storm water.

Sanitary Survey: An on-site review of
the water sources, facilities, equip-
ment, operation and maintenance of a
public water system to evaluate the
adequacy of those elements for produc-
ing  and  distributing  safe  drinking
water.

Sanitary Water (Also known as gray
water): Water discharged from sinks,
showers, kitchens, or other nonindus-
trial operations, but  not  from  com-
modes.

Sanitation: Control of physical factors
in the human  environment that could
harm development, health, or survival.

Saprophytes: Organisms living on dead
or decaying organic matter that help
natural decomposition of organic mat-
ter in water.

Saturated Zone: The  area below the
water table where  all open spaces are
filled with water under pressure equal
to or greater than that of the atmo-
sphere.

Saturation: The  condition of a liquid
when it  has taken into solution the
maximum possible quantity of a given
substance at a given temperature and
pressure.

Scrap: Materials discarded from manu-
facturing operations that may be suit-
able for reprocessing.

Screening: Use of screens  to remove
coarse floating and suspended  solids
from sewage.

Science  Advisory  Board  (SAB):   A
group of external scientists who advise
EPA on science and policy. •

Scrubber An air pollution device that
uses a spray of water or reactant or a
dry process to  trap pollutants in emis-
sions.

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36
Secondary Drinking  Water  Regula-
tions:   Non-enforceable   regulations
applying to public water systems and
specifying  the maximum  contamina-
tion levels that,  in the judgment of
EPA, are required to protect the public
welfare. These regulations apply to any
contaminants  that may adversely af-
fect the  odor  or  appearance of such
water  and consequently  may cause
people served by the system to discon-
tinue its use.

Secondary Materials:  Materials  that
have been manufactured and used at
least once and are to be used again.

Secondary Standards: National  am-
bient air quality standards designed to
protect welfare, including effects on
soils, water, crops,  vegetation, man-
made  materials, animals,  wildlife,
weather, visibility, and climate; dam-
age  to property;  transportation haz-
ards; effects on economic values, and
on personal comfort and well-being.

Secondary Treatment: The  second step
in most  publicly  owned waste treat-
ment systems in  which bacteria con-
sume the organic parts of the waste. It
is accomplished by bringing together
waste,  bacteria, and oxygen in trick-
ling, filters or  in the activated sludge
process. This treatment removes float-
ing and settleable solids and about 90
percent of the  oxygen-demanding sub-
stances and suspended solids. Disinfec-
tion is the final  stage  of secondary
treatment. (See:  primary,   tertiary
treatment.)
Secure Chemical  landfill:  (See: land-
fills.)

Secure Maximum Contaminant Level:
Maximum permissible level of a con-
taminant in water delivered to the free
flowing outlet  of the ultimate user, or
of contamination resulting from corro-
sion of piping and plumbing caused by
water quality.

Sediment Yield The quantity of sedi-
ment arriving  at a specific location.

Sedimentation  Tanks:  Wastewater
tanks  in  which floating wastes  are
skimmed off and settled solids are re-
moved for disposal.

Sedimentation: Letting solids settle out
of wastewater by gravity during treat-
ment. .

Sediments: Soil,  sand, and minerals
washed from land into water, usually
after rain. They pile up in reservoirs,
rivers and harbors, destroying fish and
wildlife habitat, and clouding the wa-
ter  so  that  sunlight cannot reach
aquatic plants. Careless farming, min-
ing, and building activities will expose
sediment materials, allowing them to
wash off the land after rainfall.
Seed Protectant: A chemical  applied
before  planting to  protect seeds and
seedlings from disease or insects.
Seepage: Percolation of water through
the soil from unlined canals, ditches,
laterals, watercourses, or water stor-
age facilities.
Selective Pesticide: A chemical  de-
signed to affect only certain types of
pests, leaving other plants and animals
unharmed.
Semi-Confined Aquifer An aquifer par-
tially, confined by  soil layers of low
permeability  through which recharge
and discharge can still occur.
Senescence: The aging process. Some-
times used to describe lakes or other
bodies  of water in advanced stages of
eutrophication.
Septic  System: An  on-site system  de-
signed to treat and dispose of domestic
sewage. A typical septic system con-
sists of a tank that receives waste from
a residence or business amd a system
of tile lines or a pit for disposal of the
liquid  effluent (sludge) that remains
after decomposition of the solidis by
bacteria in the tank; must be pumped
out periodically.
Septic  Tank: An underground storage
tank for wastes from homes not con-
nected to a sewer line. Waste goes di-
rectly from the home to the tank. (See:
septic system.)
Service Connector The pipe that car-
ries tap water from a public water
main to a, building.

Service Line Sample: A one-liter sam-
ple  of water collected  according  to
federal regulations that  has  been
standing for  at least 6 hours in a ser-
vice pipeline.
Service Pipe: The pipeline extending
from the water main to the building
served or to the consumer's system.
Settleable   Solids:  Material  heavy
enough to sink  to  the  bottom of a
wastewater treatment tank.
Settling Chamber A series of screens
placed in the way of flue gases to slow
the stream of air, thus helping gravity
to pull particles  into a collection  de-
vice.
Settling Tank: A  holding  area  for
wastewater,  where  heavier particles
sink to the  bottom for  removal and
disposal.
7Q10: Seven-day, consecutive low flow
with a ten year return frequency; the
lowest stream flow for seven consecu-
tive days that would be expected to
occur once in ten years.

Sewage:  The waste  and wastewater
produced by residential and commer-
cial sources  and discharged into sew-
ers.

Sewage Lagoon: (See: lagoon.)

Sewage Sludge: Sludge produced at a
Publicly Owned Treatment Works, the
disposal of which is  regulated under
the Clean Water Act.

Sewer A channel or  conduit that car-
ries wastewater and storm-water run-
off from  the source to a treatment
plant or receiving stream. "Sanitary"
sewers carry  household,  industrial,
and commercial waste. "Storm" sewers
carry runoff from rain or snow. "Com-
bined"  sewers handle both.

Sewerage: The entire system of sewage
collection, treatment, and disposal.

Sharps: Hypodermic needles, syringes
(with or without the  attached needle)
pasteur pipettes, scalpel blades, blood
vials,  needles with attached tubing,
and culture  dishes used in animal or
human patient care or treatment, or in
medical,  research or industrial labo-
ratories. Also included are other types
of broken or unbroken glassware that
were in contact with infectious agents,
such as used  slides  and cover  slips,
and unused hypodermic and suture
needles, syringes, and scalpel blades.

Shock  Load: The arrival at a water
treatment plant of raw water contain-
ing unusual amounts of algae, colloidal
matter, color,  suspended solids, tur-
bidity,  or other pollutants.

Short-Circuiting: When some of  the
water in  tanks or basins flows faster
than the rest; may result in shorter
contact, reaction, or settling times than
calculated or presumed.

Signal: The volume  or product-level
change produced by a leak in a tank.

Signal  Words: The words used on a
pesticide label—Danger, Warning, Cau-
tion—to indicate level of toxicity.

Significant Deterioration: Pollution re-
sulting from a new source in previous-
ly "clean" areas.  (See: prevention of
significant deterioration.)

Significant Municipal Facilities: Those
publicly  owned  sewage  treatment
plants that discharge a million gallons
per day  or  more and are therefore
considered by states to have the poten-

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                                                                                                          37
tial to substantially effect the quality
of receiving waters.

Significant Non-Compliance: (See: sig-
nificant violations.)
Significant Violations: Violations by
point source dischargers  of sufficient
magnitude or duration to be a regula-
tory priority.

Silt: Sedimentary materials composed
of fine or intermediate-sized mineral
particles.

Silviculture:  Management  of forest
land for timber.
Sink: Place in the environment where
a compound or material collects.

Sinking: Controlling oil spills by using
an agent to trap the oil and sink it to
the  bottom of the body of water where
the  agent and the oil are biodegraded.

Site: An area or place within the juris-
diction of the  EPA and/or a  state.

Site Assessment Program: A means of
evaluating hazardous  waste  sites
through preliminary assessments and
site inspections  to develop  a Hazard
Ranking System score.

Site Inspection: The collection of infor-
mation from a Superfund site to deter-
mine  the extent and severity of haz-
ards posed by the site. It follows and is
more  'extensive  than a  preliminary
assessment. The purpose is to gather
information necessary to score the site,
using the Hazard Ranking System, and
to determine if it presents an immedi-
ate  threat requiring prompt removal.

Site Safety Flan: A cruciaL element in
all removal actions, it includes infor-
mation on equipment being used, pre-
cautions to be taken, and steps to take
in the event of an on-site emergency.

Siting: The process of choosing a loca-
tion for  a facility.

Skimming: Using a machine to remove
oil or scum from the surface of the
water.

Slow Sand Filtration: Passage of raw
water through a bed of sand at low
velocity, resulting in substantial  re-
moval of chemical and biological con-
taminants.

Sludge:  A semi-solid residue from any
of a number of air or water  treatment
processes; can be a hazardous waste.

Sludge Digester. Tank in which com-
plex organic  substances like sewage
sludges  are biologically dredged. Dur-
ing  these reactions, energy is released
and much of the sewage is converted to
methane, carbon dioxide, and water.
Slurry: A watery mixture of insoluble
matter resulting from some pollution
control techniques.
Small Quantity Generator (SQG-some-
times referred to as "Squeegee"): Per-
sons or enterprises that produce 220-
2200 pounds per month of hazardous
waste; are required to keep more  re-
cords than conditionally exempt gener-
ators. The largest category of hazard-
ous waste generators, SQGs include
automotive shops, dry cleaners, photo-
graphic developers, and a host of other
small businesses. (See: conditionally
exempt generators).
Smelter. A facility that melts or fuses
ore, often with an accompanying chem-
ical change, to separate its metal con-
tent.  Emissions  cause  pollution.
"Smelting" is the process involved.  '
Smog: Air pollution associated with
oxidants. (See: photochemical smog.)
Smoke: Particles suspended in air after
incomplete combustion.
Soft Detergents: Cleaning agents that
break down in nature.
Soft Water: Any water that does not
contain  a significant amount of dis-
solved minerals such as salts of calci-
um or magnesium.
Soil  Adsorption Field: A sub-surface
area containing a trench or bed with
clean stones and a system of piping
through which treated sewage may
seep into the surrounding soil for fur-
ther treatment and disposal.
Soil and Water Conservation Practices:
Control measures consisting of mana-
gerial, vegetative, and structural prac-
tices to reduce the loss of soil and
water.
Soil Conditioner: An organic material
like humus or compost that helps soil
absorb water, build a bacterial commu-
nity, and take up mineral nutrients.
Soil Erodibility: An indicator of a soil's
susceptibility to raindrop impact, run-
off, and other erosive processes.
Soil Gas: Gaseous elements and com-
pounds in the small spaces between
particles of the earth and soil. Such
gases can be moved or driven out un-
der pressure.
Soil Sterilante A chemical that tempo-
rarily or permanently prevents  the
growth of all plants and animals.
Solder Metallic compound used to seal
joints between pipes.  Until recently,
most solder contained 50 percent lead.
Use  of lead solder containing more
than 0.2 percent lead in pipes carrying
drinking water is now prohibited.

Sole-Source Aquifer An aquifer  that
supplies 50-percent or more pf the
drinking water of an area.

Solid Waste:  Non-liquid, non-soluble
materials  ranging  from  municipal
garbage to industrial wastes that con-
tain complex and sometimes hazardous
substances. Solid wastes also  include
sewage  sludge,  agricultural  refuse,
demolition wastes,  and  mining resi-
dues. Technically,   solid  waste  also
refers to liquids and gases in contain-
ers.

Solid Waste Disposal: The final place-
ment of refuse that  is  not salvaged or
recycled.

Solid Waste Management: Supervised
handling of waste materials from their
source through recovery processes to
disposal.

Solidification and Stabilization: Remov-
al of wastewater  from a  waste or
changing it chemically to make it less
permeable and susceptible to transport
by water.

Soot:  Carbon dust formed by incom-
plete combustion.

Sorption: The action of soaking up or
attracting substances; process  used in
many pollution control systems.

Source  Reduction:   Reducing   the
amount of  materials entering   the
waste stream by redesigning products
or patterns of production or consump-
tion  (e.g., using returnable beverage
containers). Synonymous with waste
reduction.

Source Separation: Segregating various
wastes at the point of generation (e.g.,
separation of paper, metal  and glass
from other wastes to  make recycling
simpler and more efficient.)

Special Review: Formerly known as
Rebuttable Presumption Against Regis-
tration (RPAR), this is the regulatory
process through which existing pesti-
cides suspected of posing unreasonable
risks  to  human  health,  non-target
organisms,  or the  environment  are
referred for review  by EPA. Such re-
view requires an intensive risk/benefit
analysis with  opportunity for public
comment. If risk is found to outweigh
social and economic benefits,  regula-
tory  actions ranging from label revi-

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 38
. sions and use-restriction to cancella-
 tion or suspended registration can be
 initiated.

 Special Waste: Items such as house-
 hold hazardous waste, bulky wastes
 (refrigerators, pieces of furniture, etc.)
 tires, and used oil.

 Species: A reproductively isolated ag-
 gregate of interbreeding organisms.

 Specific Conductance: Rapid method of
 estimating the dissolved solid content
 of a water supply by testing its capaci-
 ty to carry an electrical current.

 Specific Yield The amount of water a
 unit volume  of saturated permeable
 rock will yield when drained by gravi-
 ty.
 Spill Prevention Control and Counter-
 measures Plan (SPCP): Plan covering
 the release of hazardous substances as
 defined in the Clean Water Act.

 Spoil: Dirt or rock removed from its
 original location—destroying the compo-
 sition of the soil in the process—as in
 strip-mining, dredging, or construction.

 Sprawl: Unplanned  development  of
 open land.

 Spray Tower  Scrubber A device that
 sprays alkaline water into a chamber
 where acid gases are present to aid in
 the  neutralizing of the gas.
 Spring: Ground  water seeping out of
 the  earth where the water table inter-
 sects the ground surface.
 Spring Mell/Thaw: The process where-
 by  warm temperatures melt  winter
 snow and ice. Because various forms of
 acid deposition may have been stored
 in the frozen water, the melt can result
 in abnormally large amounts of acidity
 entering streams  and rivers, some-
 times causing fish kills.

 Stable Air. A motionless mass of air
 that holds instead of dispersing pollut-
 ants.
 Stabilization:  Conversion of the active
 organic matter in sludge  into inert,
 harmless material.

 Stabilization Ponds: (See: lagoon.)
 Stack: A chimney, smokestack, or ver-
 tical pipe that discharges used air.
 Stack Effect: Air, as in a chimney, that
 moves upward because it  is  warmer
 than the ambient atmosphere.
 Stack Gas: (See: flue gas.)

 Stage II Controls:  Systems placed on
 service station gasoline pumps to con-
 trol and capture gasoline vapors dur-
 ing  refuelling.
 Stagnation: Lack of motion in a mass
 of air or water that holds pollutants in
 place.

 Standard Sample: The part of finished
 drinking water that is  examined for
 the presence of coliform  bacteria.

 Standards: Norms that  impose limits
 on the amount of pollutants or emis-
 sions produced. EPA establishes mini-
 mum standards, but states are allowed
 to be stricter.

 Start of a Response Action: The point
 in time when there is a guarantee or
 set-aside of funding either  by EPA,
 other federal agencies, states or Princi-
 pal  Responsible  Parties in  order to
 begin response actions at a Superfund
 site.

 State Emergency Response  Commis-
 sion (SERC): Commission appointed by
 each state  governor according  to  the
 requirements of  SARA Title III. The
 SERCs designate emergency planning
 districts, appoint local emergency plan-
 ning committees, and supervise and
 coordinate their activities.

 State Implementation  Flans  (SIP):
 EPA-approved state plans for the es-
 tablishment, regulation, and enforce-
 ment of air pollution standards.
 Static Water Depth: The vertical dis-
 tance from the center-line .of the pump
 discharge down to the surface level of
 the free pool while no water is being
 drawn from the pool or water table.

 Static Water Level:  1.  Elevation or
level of the water table in a well when
the pump is not operating. 2. The level
or elevation to which water would rise
in a tube  connected to an artesian
aquifer or basin in a conduit  under
pressure.

 Stationary Source: A fixed-site produc-
er of pollution, mainly  power  plants
 and  other  facilities using industrial
combustion processes.

Sterilization: The removal  or destruc-
tion  of all microorganisms, including
pathogenic and other bacteria, vegeta-
tive forms, and spores.
Storage: Temporary holding of waste
pending treatment or disposal, as in
containers,  tanks, waste  piles,  and
surface impoundments.
Storm Sewer A system of pipes (sepa-
rate  from sanitary sewers) that carries
only water runoff from buildings and
 land surfaces.
 Stratification: Separating into layers.
Stratosphere: The portion of the atmo-
sphere 10-to-25 miles above the earth's
surface.                     •

Strip-Cropping:  Growing  crops  in  a
systematic arrangement of strips or
bands that serve as barriers to  wind
and water erosion.

Strip-Mining: A process that uses ma-
chines to scrape soil or rock away from
mineral deposits just under the earth's
surface.

Structural Deformation: Distortion in
walls of a tank after liquid has  been
added or removed.

Subchronic: Of intermediate duration,
usually  used to describe  studies  or
periods of exposure lasting between 5
and 90 days

Submerged Aquatic Vegetation: Vege-
tation such as sea grasses that cannot
withstand excessive drying and there-
fore live with their leaves  at or below
the water surface; an important habi-
tat for young fish and  other aquatic
organisms.

Sulfur Dioxide (SOJ: A pungent, color-
less, gaseous pollutant formed primari-
ly by the combustion of fossil fuels.
Sump: A pit or tank that catches liquid
runoff for drainage or disposal.
Superchlorination:  Chlorination  with
doses that are deliberately selected to
produce water free of combined residu-
als so large  as  to require dechlorina-
tion.

Supercritical Water A type of thermal
treatment using moderate tempera-
tures  and high pressures to enhance
the ability of water to break down
large  organic molecules into smaller,
less toxic ones. Oxygen injected during
this process combines  with  simple
organic compounds to form carbon di-
oxide and water.

Superfund:  The  program  operated
under the  legislative  authority  of
CERCLA  and SARA that funds and
carries out EPA solid waste emergency
and long-term removal  and remedial
activities. These  activities  include
establishing the  National Priorities
Last, investigating sites for inclusion
on the list, determining their priority,
and conducting  and/or supervising the
cleanup and other remedial actions.
Superfund  Innovative  Technology
Evaluation: EPA program to promote
development and  use  of  innovative
treatment technologies  in  Superfund
site cleanups.

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                                                                                                            39
Supplier of Water Any person who
owns or operates a public water sup-
ply.
Surface Impoundment:   Treatment,
storage, or disposal of liquid hazardous
wastes in ponds.
Surface Runoff: Precipitation,  snow-
melt, or irrigation water in excess of
what can infiltrate the soil surface and
be stored in small surface depressions;
a major transporter of non-point source
pollutants.

Surface Uranium Mines: Strip mining
operations  for  removal of  uranium-
bearing ore.

Surface Water  All  water  naturally
open to the atmosphere (rivers, lakes,
reservoirs,  ponds, streams,  impound-
ments, seas, estuaries, etc.) and all
springs, wells, or other collectors di-
rectly influenced by surface water.

Surfacing  ACM:  Asbestos-containing
material that is sprayed or troweled on
or otherwise applied to surfaces, such
as acoustical plaster on ceilings and
fireproofing materials  on  structural
members.

Surfacing Material: Material sprayed
or troweled onto  structural  members
(beams, columns, or decking) for fire
protection;  or on  ceilings or walls for
fireproofing, acoustical  or decorative
purposes.  Includes  textured plaster,
and  other  textured wall  and ceiling
surfaces.

Surfactant: A detergent compound that
promotes lathering.

Surveillance System: A series of moni-
toring devices designed to  check on
environmental conditiona.

Suspect Material: Building material
suspected of containing asbestos, e.g.,
surfacing material, floor tile, ceiling
tile,  thermal system insulation, and
miscellaneous other materials.

Suspended Loads: Sediment particles
maintained in the  water column by
turbulence  and carried with the flow of
water.

Suspended Solids: Small particles of
solid pollutants that float on the sur-
face  of, or are suspended in) sewage or
other liquids. They resist removal by
conventional means.

Suspension: Suspending the use of a
pesticide when EPA deems it necessary
to prevent an imminent hazard result-
ing from its continued use.  An emer-
gency suspension takes effect imme-
diately; under an ordinary suspension
a  registrant can request a  hearing
before the suspension goes into effect.
Such a hearing process might take six
months.

Suspension Culture: Cells growing in a
liquid nutrient medium.

Swamp: A type of wetland dominated
by woody vegetation but without ap-
preciable peat deposits. Swamps may
be fresh or salt water and  tidal- or
non-tidal. (See: wetlands.)

Synergism: An interaction of two or
more chemicals that results  in an ef-
fect  greater than  the sum  of their
separate effects.

Synthetic Organic Chemicals (SOCs):
Man-made  organic  chemicals.  Some
SOCs are volatile, others tend to stay
dissolved in water instead of evaporat-
ing.

System With a Single Service Connec-
tion: A system that supplies drinking
water to consumers via a single service
line.

Systemic Pesticide:  A chemical  ab-
sorbed by an organism that makes the
organism toxic to pests.
Tailings: Residue of raw material or
waste separated out during the pro-
cessing of crops or mineral ores.
Tailpipe Standards: Emissions limita-
tions applicable to mobile source en-
gine exhausts.
Tail Water. The  runoff of irrigation
water from the lower end of an irrigat-
ed field.
Tampering:  Adjusting,  negating,  or
removing pollution control equipment
on a motor vehicle.
Technical Assistance Grant (TAG): As
part of the Superfund program, Tech-
nical  Assistance  Grants of  up  to
$60,000  are  provided  to  citizens'
groups to obtain  assistance  in  inter-
preting information related to cleanups
at Superfund sites or those  proposed
for the National Priorities Last. Grants
are used by such groups to hire techni-
cal advisors to help them understand
the site-related technical information
for the duration of response activities.
Technology-Based Limitations: Indus-
try-specific effluent limitations applied
to a discharge when it will not cause a
violation of water quality standards at
low stream flows.  Usually applied to
discharges into large rivers.

Technology-Based Standards: Effluent
limitations applicable  to  direct and
indirect sources  which are 'developed
on a category-by-category  basis using
statutory factors, not including water-
quality effects.

Teratogenesis: The introduction of non-
hereditary birth defects in a developing
fetus  by exogenous  factors such  as
physical or chemical agents acting in
the womb  to  interfere with normal
embryonic development.

Terracing: Dikes built  along the con-
tour of  sloping  farm land that hold
runoff and sediment to reduce erosion.

Tertiary Treatment: Advanced cleaning
of wastewater that goes  beyond  the
secondary or biological stage, removing
nutrients such as  phosphorus, nitro-
gen, and most BOD and  suspended
solids.

Therapeutic Index: The ratio of the
dose required to produce toxic or lethal
effects to dose  required  to produce
nonadverse or therapeutic response.

Thermal Pollution: Discharge of heated
water from industrial  processes; can
kill or injure aquatic organisms.

Thermal Stratification: The formation
of layers of different temperatures in a
lake or reservoir.
Thermal  System  Insulation  (TSI>
Asbestos-containing material applied to
pipes,  fittings,  boilers,   breeching,
tanks, ducts, or other  interior struc-
tural components to prevent heat loss
or gain or water condensation.

Thermal Treatment: Use  of elevated
temperatures  to   treat   hazardous
wastes. (See: incineration; pyrolysis.)
Thermodine: The  middle layer of a
thermally stratified lake or reservoir.
In this layer there is a rapid decrease
in temperatures  in a lake or reservoir.

Threshold: The lowest dose of a chemi-
cal at which a  specified measurable
effect is observed and below which it is
not observed.

Threshold Level: Time-weighted aver-
age pollutant concentration values,
exposure beyond which  is likely  to
adversely affect  human health. (See:
environmental exposure)

Threshold  Limit  Value  (TLV): The
concentration of an airborne substance
that an average  person can be repeat-
edly exposed to without adverse effects.

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40
TLVs may be expressed in three ways:
TLV-TWA-Time  weighted   average,
based on  an allowable exposure aver-
aged over a normal 8-hour workday or
40-hour workweek; TLV-STEL-Short-
term exposure limit or maximum con-
centration for a brief specified period of
time, depending on a specific chemical
(TWA must still be met); and TLV-C-
Ceiling Exposure Limit or maximum
exposure  concentration not  to be ex-
ceeded under any circumstances. (TWA
must still be met.)

Threshold Odor (See: Odor threshold)
Threshold Planning Quantity: A quan-
tity  designated for each chemical on
the  list of extremely hazardous  sub-
stances that triggers  notification by
facilities to the State Emergency Re-
sponse Commission that such facilities
are subject to emergency planning re-
quirements under SARA Title III.

Tidal Marsh: Low, flat marshlands tra-
versed by channels and tidal hollows,
subject to tidal inundation;  normally,
the  only  vegetation present is salt-
tolerant  bushes  and  grasses.  (See:
wetlands.)

Tillage: Plowing, seedbed preparation,
and  cultivation practices.

Total Suspended Particles: A method of
monitoring particulate matter by total
weight.

Time-weighted Average (TWA): In air
sampling, the average air concentra-
tion  of contaminants during a given
period.
Tolerances:  Permissible residue levels
'for pesticides in raw agricultural pro-
duce and processed foods. Whenever a
pesticide is registered for use on a food
or a  feed crop, a tolerance (or exemp-
tion  from the  tolerance requirement)
must be established. EPA establishes
the tolerance levels, which are enforced
by the Food and Drug Administration
and  the Department of Agriculture.

Tonnage: The amount of waste that a
landfill  accepts,  usually expressed in
tons per month. The rate at which a
landfill accepts waste is limited by the
landfill's permit.

Topography: The physical features of a
surface  area including relative  eleva-
tions and  the position of natural and
man-made features.
Total Dissolved Phosphorous: The total
phosphorous content  o. all  material
that will pass through a filter, which is
determined as orthophosphate without
prior digestion  or hydrolysis.  Also
called soluble P. or ortho P.
Total Dissolved Solids (TDS): All mate-
rial  that  passes  the standard glass
river filter; now called total filterable
residue. Term is used to reflect salini-
ty.

Total Suspended Solids (TSS): A mea-
sure  of  the suspended  solids  in
wastewater, effluent, or water bodies,
determined by tests for "total suspend-
ed non-filterable solids." (See: suspend-
ed solids.)

Toxaphene: Chemical that causes ad-
verse health  effects in domesic  water
supplies and is toxic to fresh water and
marine aquatic life.

Toxic Chemical Release Form:  Infor-
mation form required of facilities that
manufacture, process, or use (in quan-
tities above a specific amount) chemi-
cals listed under SARA Title III.

Toxic Chemical: Any chemical listed in
EPA rules as  "Toxic Chemicals Subject
to Section 313 of the Emergency Plan-
ning and  Community Right-to-Know
Act of 1986."

Toxic Chemical Use Substitution: Re-
placing toxic chemicals with less harm-
ful chemicals in industrial processes.

Toxic Cloud: Airborne plume of gases,
vapors, fumes, or aerosols containing
toxic materials.

Toxic Pollutants: Materials that cause
death, disease, or birth defects  in or-
ganisms that ingest  or  absorb  them.
The  quantities and exposures neces-
sary to  cause these  effects  can vary
widely.
Toxic Release Inventory: Database of
toxic releases in the United States
compiled from SARA Title III section
313 reports.
Toxic Substance: A chemical or mix-
ture that may present an unreasonable
risk of injury to health or the environ-
ment.
Toxic Waste: A waste that can produce
injury if inhaled,  swallowed, or ab-
sorbed through the skin.
Toxicant:  A  harmful  substance  or
agent that may  injure  an exposed
organism.
Toxitity Assessment: Characterization
of the toxicological properties and ef-
fects of a  chemical, with special em-
phasis  on establishment of dose-re-
sponse characteristics.

Tooricity  Testing:  Biological testing
(usually with an invertebrate, fish, or
small mammal) to determine the ad-
verse effects  of a  compound or efflu-
ent.
Toxicological Profile: An examination,
summary, and interpretation of a haz-
ardous substance to determine levels of
exposure and associated health effects.

Transboundary Pollutants: Air pollu-
tion that travels from one jurisdiction
to  another,  often crossing state  or
international boundaries. Also applies
to water pollution.

Transient Water System:  A non-com-
munity water system that does  not
serve 25 of the same nonresidents per
day for more than six months per year.
Transmission Lines: Pipelines that
transport raw water from its source to
a water treatment plant,  then to the
distribution grid system.

Transmissivity: The ability of an aqui-
fer to transmit water,

Transpiration: The process  by which
water vapor is lost to the  atmosphere
from living plants. The term can also
be  applied to the quantity of "water
thus dissipated.

Transportation   Control   Measures
(TCMs): Steps taken by a locality to
adjust traffic patterns (e.g., bus lanes,
turnout, right turn on red) or reduce
vehicle use (ride sharing, high-occu-
pancy vehicle lanes) to cut  vehicular
emissions.

Trash: Material considered worthless
or offensive that is thrown away. Gen-
erally defined as dry waste material,
but in common usage it is a synonym
for garbage, rubbish, or refuse.
Trash-to-Energy Han: Burning trash
to produce energy.

Treatability Studies: Tests of potential
cleanup technologies conducted in  a
laboratory (See: bench-scale tests.)

Treated  Regulated  Medical  Waste:
Medical waste treated to substantially
reduce or eliminate its pathogenicity,
but that has not yet been destroyed.

Treated Wastewater: Waste-water that
has been subjected  to one or more
physical, chemical, and biological pro-
cesses to reduce its pollution or health
hazards.

Treatment: (1) Any method, technique,
or process  designed  to remove solids
and/or pollutants  from solid waste,
wastestreams, effluents, and air emis-
sions. (2) methods used to change the
biological character or composition of
any regulated medical waste so as to
substantially reduce or eliminate its
potential for causing disease.

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                                                                                                        41
Treatment Plant: A structure built to
treat wastewater before discharging it
into the environment

Treatment,  Storage,  and  Disposal
Facility: Site where a hazardous sub-
stance is treated, stored, or disposed
of. TSD facilities are regulated by EPA
and states under RCRA.

Tremie: Device used to place concrete
or grout under water.

Trial Burn: An incinerator test in
which emissions are monitored for the
presence of specific organic compounds,
particulates, and hydrogen chloride.
Trichloroethyiene (TCE): A stable, low
boiling-point colorless liquid, toxic if in-
haled. Used as a solvent or metal de-
greasing agent, and in other industrial
applications.

Trickling Filter A coarse treatment
system in which wastewater is trickled
over a bed of stones or other material
covered with bacteria that break down
the organic waste and produce clean
water.

Trickle  Irrigation:  Method in which
water drips to the soil from perforated
tubes or emitters.
TVihiil««M«»t>nin«» ^TOM): One of a fami-
ly of organic compounds named as
derivative of methane. THMs are gen-
erally by-products  of  chlorination of
drinking water  that contains organic
material.
Troposhpere: The layer of the atmo-
sphere closest to the earth's surface.
Trust Fond (CERCLA): A fund set up
iinA»r the Comprehensive Environmen-
tal Response, Compensation and Lia-
bility Act (CERCLA) to  help pay for
cleanup of hazardous waste sites  and
for legal action to force those responsi-
ble for the sites  to clean them up.

Tube Settler Device using bundles of
tubes to let solids in water settle to the
bottom for removal by  conventional
sludge  collection  means; sometimes
used in sedimentation basing and clari-
fiers to improve particle removal.
Tuberculation: Development or forma-
tion of small mounds of corrosion  pro-
ducts on the inside of iron pipe. These
tubercules roughen the imiide of the
pipe, increasing its resistance to water
flow.

Tundra: A type of ecosystem dominat-
ed by  lichens, mosses, grasses,  and
woody plants. Tundra is found at high
latitudes (arctic tundra) and high alti-
tudes (alpine tundra). Arctic tundra is
underlain by permafrost and is usually
saturated. (See: wetlands.)
Turbidimeter A device that measures
the density of suspended solids in a
liquid.

Turbidity: 1. Haziness in air caused by
the presence of particles and pollut-
ants. 2. A cloudy condition in water
due to suspended silt or organic mat-
ter.
u

Ultra Clean Coal (UCC): Coal that is
washed, ground into  fine particles,
then  chemically treated to  remove
sulfur, ash, silicone,  and other sub-
stances; usually briquetted and coated
with a sealant made from coal.
Ultraviolet Rays: Radiation from the
sun that can be useful or potentially
harmful. UV rays from one part  of the
spectrum (UV-A) enhance plant life
and are useful  in some  medical and
dental procedures; UV rays from other
parts of the  spectrum (UV-B)   can
cause skin cancer or other tissue dam-
age. The ozone layer in the atmosphere
partly shields us from ultraviolet rays
reaching the earth's surface.
Unconfined Aquifer An  aquifer con-
taining water that is not under pres-
sure; the water level in a well  is the
same as the water table outside the
well.
Underground Injection Control (UIC>
The program under the Safe Drinking
Water Act that regulates the use  of
wells to pump fluids into the ground.
Underground  Sources  of Drinking
Water  Aquifers currently being used
as a source of drinking water or those
capable of  supplying a public  water
system. They have a total dissolved
solids content of 10,000 milligrams per
liter  or less, and are  not "exempted
aquifers." (See: exempted aquifer.)
Underground  Storage  Tank:  A tank
located at least partially underground
and designed to hold gasoline or other
petroleum products or chemicals.
Unreasonable Risk: Under the Federal
Insecticide, Fungicide, and Rodenticide
Act (FIFRA), "unreasonable adverse ef-
fects" means any unreasonable risk to
man  or the environment, taking into
account the medical, economic, social,
and environmental  costs and benefits
of any pesticide.
Unsaturatod Zone: The area above the
water table where  soil pores are not
fully saturated, although some water
may be present

Uranium Mill Tailing! Piles: Former
uranium ore processing sites that con-
tain leftover  radioactive  materials
(wastes), including radium and unre-
coverad uranium.

Uranium Mill-Tailings Waste Piles: Li-
censed active mills with tailings piles
and evaporation ponds created by acid
or alkaline leaching processes.

Urban Runoff:  Storm water from city
streets and adjacent domestic or com-
mercial properties that carries pollut-
ants of various kinds into the sewer
systems and receiving waters.

Urea-Formaldehyde Foam Insulation:
A material once used to conserve ener-
gy by sealing crawl spaces, attics, etc.;
no longer used because emissions were
found to be a health hazard.

User Fee: Fee collected from only those
persons  who use a particular service,
as compared to one collected from the
public in general.

Utility Load: The total electricity de-
mand for a utility district
                                    Vapor Capture System: Any combina-
                                    tion of hoods and ventilation system
                                    that, captures or contains organic va-
                                    pors so they may be  directed to an
                                    abatement or recovery  device.

                                    Vapor Dispersion:  The movement of
                                    vapor clouds in air due to wind, ther-
                                    mal  action, gravity spreading, and
                                    mi-ring

                                    Vapor Plumes: Flue gases visible be-
                                    cause they contain water droplets.

                                    Variance: Government permission for
                                    a delay or exception in the application
                                    of a given law, ordinance, or regula-
                                    tion.

                                    Vector 1. An organism, often an insect
                                    or rodent, that carries  disease. 2. Pla-
                                    amids,  viruses, or bacteria used  to
                                    transport genes into a host cell. A gene
                                    is placed in the vector;  the vector then
                                    "infects" the bacterium.

                                    Vegetative Controls: Non-point source
                                    pollution control practices that involve
                                    vegetative cover to reduce erosion and
                                    minimi™ loss of pollutants.

                                    Vehicle Miles Travelled (VMT> A mea-
                                    sure of the extent of motor vehicle
                                    operation; the total number of vehicle
                                    miles travelled within a specific geo-

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42
graphic area over a given period of
time.

Ventilation/Suction: The act of admit-
ting fresh air into a space in order to
replace stale  or contaminated  air;
achieved by blowing air into the space.
Similarly, suction represents  the  ad-
mission of fresh  air into an  interior
space by lowering the pressure outside
of the space, thereby drawing the con-
taminated air outward.

Venturi Scrubbers: Air pollution con-
trol devices that use water to remove
particulate matter from emissions.

Vinyl Chloride: A chemical compound,
used in producing some  plastics, that
is believed to be oncogenic.

Virgin Materials: Resources extracted
from nature in their raw  form, such as
timber or metal ore.

Volatile: Any  substance that evapo-
rates readily.

Volatile Liquids: Liquids which easily
vaporize or evaporate at room tempera-
ture.

Volatile Organic Compound  (VOC>.
Any organic compound  that  partici-
pates in atmospheric photochemical
reactions except those designated by
EPA as having negligible photochemi-
cal reactivity.

Volatile Solids Those solids in water or
othr liquids that are lost  on ignition of
the dry solids at 550* Centigrade.
Volatile Synthetic Organic Chemicals:
Chemicals that tend to volatilize or
evaporate.
Volume Reduction: Processing waste
materials to decrease the amount of
space they occupy, usually by compact-
ing  or  shredding,  incineration,  or
composting.
Volumetric Tank Test: One of several
tests to determine the physical integri-
ty of a storage tank; the volume of
fluid in the tank is measured directly
or calculated from product-level chang-
es. A marked drop in volume indicates
a leak.
Vulnerable Zone:  An area over which
the airborne concentration of a chemi-
cal  accidentally released could reach
the level of concern.
Vulnerability Analysis: Assessment of
elements in the  community that are
susceptible to damage should a release
of hazardous materials occur.
 w

 Waste: 1. Unwanted materials left over
 from a manufacturing process. 2. Re-
 fuse from places of human or animal
 habitation.

 Waste Characterization: Identification
 of chemical and microbiological constit-
 uents of a waste material.

 Waste  Exchange:  Arrangement' in
 which  companies  exchange  their
 wastes for the benefit of both parties.

 Waste Feed: The continuous or inter-
 mittent flow of wastes into an incin-
 erator.

 Waste Load Allocation: 1.  The maxi-
 mum load of pollutants each discharg-
 er of waste is allowed to release into a
 particular waterway. Discharge limits
 are usually required for each specific
 water quality criterion being, or ex-
 pected to be, violated. 2. The portion of
 a stream's  total  assimilative capacity
 assigned to an individual discharge.

 Waste Minimization: Measures or tech-
 niques  that  reduce  the  amount of
 wastes generated  during industrial
 production processes; term is also ap-
 plied to recycling and other efforts to
 reduce the amount of waste going into
 the waste, stream.
 Waste Reduction: Using source reduc-
 tion, recycling, or composting to pre-
 vent or reduce waste generation.
 Waste Stream: The total flow of solid
 waste from homes, businesses, institu-
 tions, and manufacturing plants that
 are. recycled, burned, or disposed of in
 landfills, or segments thereof such as
 the "residential waste stream" or the
 "recyclable waste stream."
 Waste Treatment  Lagoon: Impound-
 ment made by excavation or earth fill
 for biological treatment of wastewater.

 Waste Treatment Plant* A facility con-
 taining a series of tanks, screens, fil-
 ters and  other  processes by which
 pollutants are removed from water.

"Waste Treatment Stream: The continu-
 ous movement of waste from generator
 to treater and disposer.
 Wastewater The spent or used water
 from a home, community, farm, or
 industry that contains  dissolved or
 suspended matter.
 Wastewater Infrastructure: The plan
 or network for the collection, treat-
 ment, and disposal of sewage  in a
 community.  The  level of treatment
 will depend on the size of the commu-
nity, the type of discharge, and/or the
designated use of the receiving water.

Wastewater Operations and Mainte-
nance: Actions taken after construction
to assure that facilities constructed to
treat  wastewater  will be  operated,
maintained, and managed to reach pre-
scribed effluent levels in an optimum
manner.

Water Pollution: The presence in water
of enough  harmful or objectionable
material to damage the water's quality.

Water Purveyor A public utility, mu-
tual water  company,  county  water
district, or municipality that delivers
drinking water to customers.

Water Quality Criteria: Levels of water
quality expected to render a body of
water suitable for its designated use.
Criteria are. based on specific levels of
pollutants that would make the water
harmful if used for drinking, swim-
ming, farming,  fish  production, or
industrial processes.

Water Quality Standards: State-adopt-
ed and EPA-approved ambient  stan-
dards for water bodies. The standards
prescribe the use of the  water body
and establish the water quality criteria
that must be met to protect designated
uses.

Water  Quality-Based  Limitations:
Effluent  limitations  applied  to dis-
chargers when mere technology-based
limitations would cause violations of
water quality standards. Usually ap-
plied to discharges into small streams.

Water Quality-Baaed Permit A permit
with an effluent limit more stringent
than one based on technology perfor-
mance. Such limits may be necessary
to protect the designated use of receiv-
ing waters (i.e., recreation, irrigation,
industry or water supply).

Water Solubility: The mummim possi-
ble concentration of a chemical com-
pound dissolved in water. If a sub-
stance is water soluble it can very
readily disperse through the environ-
ment

Water Storage Pond: An impound for
liquid wastes designed to accomplish
some degree of biochemical treatment

Water Supplier: One who owns or
operates a public water system.

Water Supply System: The collection,
treatment, storage, and distribution of
potable water from source to consumer.

Water Table: The level of grbundwater.

Water Treatment Lagoon: An impound
for liquid wastes designed to accom-

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                                                                                                          43
pilch some degree of biochemical treat-
ment.

Water Well: An excavation where the
intended use is for location, acquisi-
tion,  development,  or artificial. re-
charge of ground water.
Watorbome Disease  Outbreak;  The
significant occurence of acute infection
illness associated with drinking water
from a public water  system  that  is
deficient in treatment, as determined
by appropriate local or state agencies,
or from untreated water sources.

Watershed: The land area that drains
into a stream; the watershed for a
major river may encompass a number
of smaller watersheds that ultimately
combine at a common  point
Weir 1. A wall or plate placed in an
open  channel to  measure the  flow
ofwater. 2. A wall or obstruction used
to control flow from settling tanks and
clarifiers to assure a uniform flow rate
and avoid short-circuiting. (See: short-
circuiting.)
Well: A bored, drilled,  or driven shaft,
or a dug hole whose depth is  greater
than the largest surface dimension and
whose purpose is to reach underground
water supplies or oil, or to  store or
bury fluids below ground.

Well Field  Area containing  one or
more   wells  that  produce   usable
amounts of water or oil.
Well Injection: The  subsurface  em-
placement of fluids into a well.
Well Monitoring: Measurement by on-
sito instruments or laboratory methods
of well water quality.

Well Hug: A watertight, gantight seal
installed in a bore hole or well  to pre-
vent movement of fluids.
Wellhead Protection Area: A protected
surface and subsurface sane surround-
ing  a well or wellfield supplying a
public water system to keep contami-
nants from reaching the well water.
Wetlands: An area that is saturated by
surface or ground water with  vegeta-
tion adapted for life under those soil
conditions, as in swamps,  bogs, fens,
marshes, and estuaries.
Wildlife Refuge: An area designated for
the  protection of wild animala,  within
which hunting and fiohing are either
prohibited or strictly controlled.
Wire-to-Wire Efficiency: The efficiency
of a pump and motor together.
Wood-Burning-Stove   Pollution:  Air
pollution caused by emissions of partic-
ulate matter, carbon monoxide, total
suspended particulates, and polycyclic
organic matter  from  wood-burning
stoves.

Wood Treatment Facility: An industri-
al facility that treats lumber and other
wood products for outdoor use. The
process employs  chromated  copper
arsenate, which is regulated as a haz-
ardous material.

Working Level Month (WLM): A unit
of measure used to determine cumula-
tive exposure to radon.
Working Level (WL): A unit of measure
for  documenting  exposure  to  radon
decay products, the so-called "daugh-
ters". One working level is equal to
approximately 200 picocuries per liter.
XYZ

Xanobioto: Any biotum displaced from
its normal habitat; a chemical foreign
to a biological system.
Yard Waste: The part of solid waste
composed of grass clippings, leaves,
twigs, branches, and garden refuse.
Yellow-Boy:  Iron  oxide  flocculent
(clumps of solids  in waste or water);
usually observed  as  orange-yellow
deposits in surface streams with excess
iron content. (See: floe, flocculation.)
Yield: The quantity ofwater (expressed
as a rate of flow or total quantity per
year) that can be collected for a given
use from surface or groundwater sourc-
es.
Z-lisfc OSHA's tables of toxic and haz-
ardous air contaminants.
Zone of Aeration: The comparatively
dry soil or rock located  between the
ground surface and the top of the wa-
ter table.
Zone of Saturation: (See: saturated
zone.)
Zooplankton:  Tiny  aquatic
eaten by fish.

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Abbreviations And Acronyms

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                                                                                                                43
A&I: Alternative and Innovative
  (Wastewater   Treatment
  System)
AA: Accountable Area; Adverse
  Action; Advices of Allowance
  Assistant Administrator; As-
  sociate Administrator; Atomic
  Absorption
AAEE: American  Academy of
  Environmental Engineers
AANWR Alaskan Arctic  Na-
  tional Wildlife Refuge
AAP: Asbestos Action Program
AAPCO: American Association
  of Pesticide Control Officials
AARC: Alliance for Acid Rain
  Control
ABEL: EPA's  computer  model
  for analyzing a violator's abil-
  ity to pay a civil penalty.
ABES: Alliance for  Balanced
  Environmental Solutions
AC: Actual Commitment. Advi-
  sory Circular
A&C: Abatement and Control
ACA:  American  Conservation
  Association
ACBM:  Asbestos-Containing
  Building Material
ACE: Alliance for Clean Energy
ACEEE: American Council for
  an Energy Efficient Economy
ACFM: Actual  Cubic Feet Per
  Minute
ACL:  Alternate Concentration
  Limit. Analytical Chemistry
  Laboratory
ACM: Asbestos-Containing Ma-
  terial
ACP: Agriculture Control Pro-
  gram (Water Quality Manage-
  ment)
ACP: Air Carcinogen Policy
ACQUIRE: Aquatic Information
  Retrieval
ACQR Air Quality Control Re-
  gion
ACS: American Chemical Soci-
  ety
ACT: Action
ACTS:   Asbestos  Contractor
  Tracking System
ACWA: American Clean  Water
  Association
ACWM:  Asbestos-Containing
  Waste Material
ADABA: Acceptable Data Base
ADB: Applications  Data BaM
ADI: Acceptable Daily Intake
ADP: Automated Data Process-
  ing
ADP: AHERA Designated Per-
  son
ADQ: Audits of Data Quality
ADR: Alternate Dispute Resolu-
  tion
ADSS: Air Data Screening Sys-
  tem
ADT: Average Daily Traffic
AEA: Atomic Energy Act
AEC:  Associate  Enforcement
  Counsels
ABE: Alliance for Environmen-
  tal Education.
AEERL: Air and Energy Engi-
  neering Research Laboratory
AEM: Acoustic Emission Moni-
  toring
AERE: Association of Environ-
  mental and Resource Econo-
  mists
AES: Auger Electron Spectrome-
  try
AFA: American Forestry Associ-
  ation
AFCA: Area Fuel Consumption
  Allocation
AFCEE: Air  Force Center for
Environmental Excellence
AFS: AIRS Facility Subsystem
AFUG:  AIRS  Facility  Users
  Group
AH: Allowance Holders
AHERA:  Asbestos   Hazard
  Emergency Response Act
AIC: Active to Inert Conversion
AICUZ: Air Installation Com-
  patible Use  Zones
AID: Agency for International
  Development
AJHC:   American   Industrial
  Health Council
AIR Auto Ignition Point
AIRS:  Aerometric  Information
  Retrieval System
AL: Acceptable Level
ALA: Delta- Aminolevulinic Acid
ALA-O:  Delta-Aminolevulinic
  Acid Dehydrates
ALAPO: Association of Local Air
  Pollution Control Officers
ALARA: As Low As Reasonably
  Achievable
ALC: Application Limiting Con-
  stituent
ALJ: Administrative Law Judge
ALMS: Atomic Line Molecular
  Spectroscopy
ALR Action Leakage Rate
AMBIENS: Atmospheric Mass
  Balance of Industrially Emit-
  ted and Natural Sulfur
AMOS: Air Management Over-
  sight System
AMPS: Automatic Mapping and
  Planning System
AMSA: Association of Metropoli-
  tan Sewer Agencies
ANC: Acid Neutralizing Capaci-
ty
ANPR: Advance Notice  of Pro-
  posed Rulemaking
ANRHRD: Air, Noise. & Radia-
  tion  Health Research Divi-
  sion/ORD
ANSS:  American Nature Study
  Society
AOC: Abnormal Operating Con-
  ditions
AOD: Argon-Oxygen Decarbon-
  ization
AOML: Atlantic Oceanographic
  and Meteorological Laborato-
  ry
AP: Accounting Point
APA: Administrative Procedures
  Act
APCA: Air Pollution  Control
  Association
APCD: Air Pollution  Control
  District
APDS: Automated Procurement
  Documentation System
APHA: American Public Health
  Association
APRAC: Urban Diffusion Model
  for Carbon  Monoxide  from
  Motor Vehicle Traffic
APTI: Air Pollution Training
  Institute
APWA: American Public Works
  Association
AQ-7: Non-reactive  Pollutant
  Modelling
AQCCT:  Air-Quality  Criteria
  and Control Techniques
AQCP: Air Quality Control Pro-
  gram
AQCR Air-Quality Control Re-
  gion
AQD: Air-Quality Digest
AQDHS: Air-Quality Date Han-
  dling System
AQDM:   Air-Quality  Display
  Model
AQMA:   Air-Quality  Mainte-
  nance Area
AQMP:   Air-Quality  Mainte-
  nance Plan
AQMP: Air-Quality  Manage-
  ment Plan
AQSM: Air-Quality Simulation
  Model
AQTAD: Air-Quality  Technical
  Assistance Demonstration
Aft Administrative Record •
A&R: Air  and Radiation
ARA: Assistant  Regional Ad-
  ministrator
ARA: Associate Regional Admin-
  istrator
ARAR  Applicable or Relevant
  and Appropriate Standards,
  Limitations,  Criteria,  and
  Requirements  ••
ARB: Air  Resources Board
ARC: Agency Ranking Commit-
  tee
ARCC: American Rivers Conser-
  vation Council
ARCS:  Alternative  Remedial
  Contract Strategy
ARG:   American   Resources
  Group
ARIP: Accidental Release Infor-
  mation  Program
ARL: Air Resources Laboratory
ARM: Air Resources Manage-
  ment
ARC: Alternate Regulatory Op-
  tion
ARRP: Acid Rain Research Pro-
  gram
ARRPA: Air Resources Regional
  Pollution Assessment Model
ARS:  Agricultural  Research
  Service
ARZ: Auto Restricted Zone
AS: Area Source
ASC: Area Source Category
ASDWA:  Association of State
  Drinking Water Administra-
  tors
ASHAA:  Asbestos in Schools
  Hazard Abatement Act
ASIWCPA: Association of State
  and Interstate Water Pollu-
  tion Control Administrators
ASMDHS: Airshed Model Date
  Handling System
ASRL:  Atmospheric  Sciences
  Research Laboratory
AST:   Advanced   Secondary
  (Wastewater) Treatment
ASTHO:  Association  of State
  and Territorial Health Offi-
  cers
ASTM: American  Society for
  Testing and Materials
ASTSWMO: Association of State
  and Territorial Solid  Waste
  Management Officials
AT: Advanced Treatment. Alpha
  Track Detection
ATERIS:  Air Toxics Exposure
  and Risk Information System
ATS: Action Tracking System
ATSDR: Agency for Toxic Sub-
  stances and Disease Registry
ATTF: Air Toxics Task Force
AUSM: Advanced Utility Simu-
  lation Model
A/WPR Au/Water Pollution Re-
  port
AWRA: American Water  Re-
  sources Association
AWT:  Advanced  Wastewater
  Treatment
AWWA: American Water Works
  Association
AWWARF:   American  Water
  Works  Association  Research
  Foundation.


B
BAA:   Board  of  Assistance
  Appeals
BAC:  Biotechnology  Advisory
  Committee
BACM: Best Available Control
  Measures
BACT: Best Available Control
  Technology
BADT: Best Available Demon-
  strated Technology
BaP: Benzo(a)Pyrene
BAP: Benefits Analysis Program
BART: Best Available Retrofit
  Technology
BASIS:  Battelle's  Automated
  Search Information  System
BAT: Best Available Technology
BATEA: Best Available  Treat-
  ment  Economically Achiev-
  able
BCT: Best Control Technology
BCPCT: Best Conventional Pol-
  lutant Control Technology
BDAT:   Best   Demonstrated
  Achievable Technology
BDCT: Best Demonstrated Con-
  trol Technology
BDT: Best Demonstrated Tech-
  nology
BEJ: Best Engineering Judge-
  ment. Best Expert Judgment
BF: Bonafide Notice of Intent to
  Manufacture  or  Import
  (IMD/OTS)
BID:  Background  Information
  Document. Buoyancy Induced
  Dispersion

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44
BIOPLUME: Model to Predict
  the Maximum Extent of Ex-
  isting Humes
BMP: Best  Management Prac-
  tice^)
BMR: Baseline Monitoring Re-
  port
BO: Budget Obligations
BOA: Basic Ordering Agreement
  (Contracts)
BOD: Biochemical  Oxygen De-
  mand. Biological Oxygen De-
  mand
BOF: Basic Oxygen Furnace
BOP: Basic Oxygen Process
BOPF: Basic  Oxygen  Process
  Furnace
BOYSNC:  Running  of Year
  Significant Non-Compliers
BP: Boiling Point
BPJ:  Best  Professional Judg-
  ment
BPT: Best Practicable  Technol-
  ogy. Pest Practicable Treat-
  ment
BPWTT: Best Practical Waste-
  water Treatment Technology
BRS:  Bibliographic  Retrieval
  Service
BSI: British Standards Institute
BSO: Benzene Soluble  Organics
BTZ: Below the Treatment Zone
BUN: Blood Urea Nitrogen
CA: Citizen  Act. Competition
  Advocate. Cooperative Agree-
  ments. Corrective Action
CAA: Clean Air Act
CAA:  Compliance  Assurance
  Agreement
CAAA: Clean Mr Act  Amend-
  ments
CAER: Community  Awareness
  and Emergency Response
CAFE: Corporate Average Fuel
  Economy
CAFO:  Consent  Agree-
1  menl/Final Order
CAG: Carcinogenic Assessment
  Group
CAIR Comprehensive  Assess-
  ment of Information Rule
CALJNE: California Line Source
  Model
CAMP: Continuous Air Monitor-
  ing Program
CAN: Common Account Number
CAO: Corrective Action Order
CAP:  Corrective Action  Plan.
  Cost  Allocation  Procedure.
  Criteria Air Pollutant
CAR Corrective Action Report
CAS:  Center .for  Automotive
  Safety
CAS: Chemical Abstract Service
CASAC:  Clean Air Scientific
  Advisory Committee
CASLP: Conference on Alter-
  native State and Local Prac-
  tices
CATS:   Corrective  Action
  Tracking System
CAU: Carbon Adsorption Unit
CAU:   Command  Arithmetic
  Unit
CB: Continuous Bubbler
CBA:  Chesapeake  Bay . Agree-
  ment. Cost Benefit Analysis
CBD: Central Business District
CBI: Compliance Biomonitoring
  Inspection
CBI: Confidential Business In-
  formation
CBOD:   Carbonaceous  Bio-
  chemical Oxygen Demand
CBP: Chesapeake Bay Program
CBP: County Business Patterns
CCA: Competition in Contract-
  ing Act
CCAA: Canadian Clean Air Act
CCAP: Center for  Clean  Air
  Policy
CCEA: Conventional Combus-
  tion  Environmental  Assess-
  ment
CCHW: Citizens Clearinghouse
  for Hazardous Wastes
CCID: Confidential Chemicals
  Identification System
CCMS/NATO:  Committee  on
  Challenges of a Modern Soci-
  ety/North  Atlantic  Treaty
  Organization
CCP: Composite Correction Plan
CC/RTS:Chemical   Collection/
  Request Tracking System
CCTP: Clean  Coal Technology
  Program
CD: Climatological Data
CDB: Consolidated Data Base
CDBA: Central Data Base  Ad-
  ministrator
CDBG:  Community Develop-
  ment Block Grant
CDD:  Chlorinated
  dibenzo-p-dicorin
CDF: Chlorinated dibenzofuran
CDHS:  Comprehensive Data
  Handling System
GDI: Case Development Inspec-
  tion
CDM: Climatological Dispersion
  Model
CDM:  Comprehensive  Data
  Management
CDMQC: Climatological Disper-
  sion Model with  Calibration
  and Source Contribution
CDNS:   Climatological Data
  National Summary
CDP: Census Designated Places
CDS: Compliance Data System
CE: Categorical Exclusion. Con-
  ditionally Exempt Generator
CEA: Cooperative Enforcement
  Agreement
CEA: Cost  and Economic As-
  sessment
CEAT:   Contractor  Evidence
  Audit Team
CEARC: Canadian Environmen-
  tal  Assessment  Research
  Council
CEB: Chemical Element  Bal-
  ance
CECATS: CSB Existing Chemi-
  cals  Assessment  Tracking
  System
CEE: Center for Environmental
  Education
CEEM: Center for Energy and
  Environmental Management
CEI:  Compliance  Evaluation
  Inspection
CELRF: Canadian Environmen-
  tal Law Research Foundation
CEM:  Continuous   Emission
  Monitoring
CEMS: Continuous  Emission
  Monitoring System
CEPP:  Chemical  Emergency
  Preparedness Plan
CEQ: Council on Environmental
  Quality
CERCLA: Comprehensive Envi-
  ronmental  Response,  Com-
  pensation, and Liability Act
  (1980)
CERCLIS: Comprehensive Envi-
  ronmental  Response,  Com-
  pensation, and Liability Infor-
  mation System
CERT: Certificate of Eligibility
CF: Conservation Foundation
CFC: Chlorofluorocarbons
CFM: Chlorofluoromethanes
CFR Code of Federal Regula-
  tions
CHABA: Committee on Hearing
  and Bio-Acoustics
CHAMP:  Community  Health
  Air Monitoring Program
CHEMNET: Chemical Industry
  Emergency Mutual Aid Net-
  work
CHESS: Community Health and
  Environmental Surveillance
  System
CHIP: Chemical Hazard Infor-
  mation Profiles
CI: Compression Ignition. Confi-
  dence Interval
CIAQ:  Council on Indoor Air
  Quality   .
CIBL:  Convective  Internal
  Boundary Layer
CICA: Competition in Contract-
  ing Act
CICIS: Chemicals in Commerce
  Information System
CIDRS: Cascade Impactor Data
  Reduction System
CEMI: Committee on Integrity
  and  Management Improve-
  ment
CIS: Chemical Information Sys-
  tem. Contracts Information
  System
CLC: Capacity Limiting Constit-
  uents
CLEANS:  Clinical  Laboratory
  for Evaluation and  Assess-
  ment of Toxic Substances
CLEVER  Clinical  Laboratory
  for Evaluation and Validation
  of Epidemiologic Research
CLF: Conservation Law Foun-
  dation
CLIPS: Chemical List Index and
  Processing System
CLP: Contract Laboratory Pro-
  gram
CM: Corrective Measure
CMA: Chemical Manufacturers
  Association
CMB: Chemical Mass Balance
CME:  Comprehensive Monitor-
   ing Evaluation
CMEL: Comprehensive Moni-
   toring Evaluation Log
CMEP: Critical  Mass Energy
   Project
CNG: Compresed Natural Gas
COCO:   Contractor-Owned/
  Contractor-Operated
COD:  Chemical  Oxygen  De-
  mand
COH: Coefficient Of Haze
CPF: Carcinogenic Potency Fac-
  tor
CPO: Certified Project Officer
CQA: Construction Quality As-
  surance
CR: Continuous Radon Monitor-
  ing
CROP:  Consolidated Rules of
  Practice
CRP:   Conservation  Reserve
  Program
CRR: Center for Renewable Re-
  sources
CRSTER: Single Source Disper-
  sion Model
CSI: Compliance  Sampling In-
  spection
CSIN:  Chemical  Substances
  Information Network
CSO: Combined Sewer Overflow

CSPA:  Council of State Plan-
  ning Agencies
CSRL: Center for the Study of
  Responsive Law
CTARC: Chemical Testing and
  Assessment  Research Com-
  mission
CTG:   Control  Techniques
  Guidelines
CV: Chemical Vocabulary
CW: Continuous  working-level
  monitoring
CWA: Clean  Water Act (aka
  FWPCA)
CWAP:  Clean Water   Action
  Project
CWTC:  Chemical  Waste
  Transportation Council
CZMA: Coastal Zone Manage-
  ment Act
CZARA: Coastal Zone Manage-
  ment  Act   ^authorization
  Amendments
DAPSS: Document and Person-
  nel Security System (IMD)
DCI: Data Call-in
DCO: Delayed Compliance Or-
  der
DCO: Document Control Officer
DDT:  DichloroDiphenyl-
  Trichloroethane
DERs: Data Evaluation Records
DES: Diethylstilbesterol
DI: Diagnostic Inspection
DMR  Discharge  Monitoring
  Report
DNA: Deoxyribonucleic acid
DO: Dissolved Oxygen
DOW: Defenders  Of Wildlife
DPA: Deepwater  Ports Act
DPD:  Method  of  Measuring
Chlorine Residual in Water
DQO: Data Quality Objective
DRE: Destruction and Removal
   Efficiency
DRES: Dietary Risk Evaluation
   System
DRMS: Defense Reutilization
   and Marketing Service

-------
                                                                                                                45
DRR Data Review Record
DS: Diiixotomous Sample*
DSAR Data Self Auditing Pro-
  gram
DSCF: Dry Standard Cubic Feet
DSCM:  Dry Standard  Cubic
  Meter
DSS: Decision Support System
DSS: Domestic Sewage Study
DT: Detention Time
DT: Detectors (radon) damaged
  or lost
DU: Decision Unit. Ducks Un-
  limited
DUG: Decision Unit Coordinator
DWEL: Drinking Water Equiva-
  lent Level
DWS: Drinking Water Standard
EA: Endangerment Assessment.
  Enforcement  Agreement.
  Environmental Action. Envi-
  ronmental Assessment. Envi-
  ronmental Audit
EAF: Electric Arc Furnaces
BAG:   Exposure  Assessment
  Group
BAP:   Environmental  Action
  Plan
EAR:  Environmental Auditing
  Roundtable
EB: Emissions Balancing
EC: EmulBifiable Concentrate
EC: Environment Canada
EC: Effective Concentration
ECA: Economic Community for
  Africa
ECAP: Employee  Counselling
  and Assistance Program
BCD: Electron Capture Detector
ECHH: Electro-Catalytic Hyper-
  Heaters
ECL: Environmental Chemical
  Laboratory
ECR: Enforcement Case Review
ECRA: Economic Cleanup Re-
  sponsibility Act
ED: Effective Dose
EDA:  Emergency  Declaration
  Area
EDB: Ethylene Dibromide
EDC: Ethylene Dichloride
EDD:   Enforcement Decision
  Document
EDF:  RiwiTmmMmt.nl DefOOM
  Fund
  Retrieval System
EDS: Electronic Data System
EDS: Energy Data System
EDTA:   Ethylene  Diamine
  Triacetic Acid
EDX: Electronic Data Exchange
EDZ: Emission Density Zoning
RRA; Energy and Environmen-
  tal Analysis
EECs: Estimated Environmen-
  tal Concentrations
EER Excess Emission Report
EERL: Eastern Environmental
  Radiation Laboratory
EERU: Environmental  Emer-
  gency Response Unit
EESI: Environment and Energy
  Study Institute
EESL:  Environmental Ecologi-
  cal and Support Laboratory
EETFC: Environmental Effects,
  Transport, and Fate Commit-
  tee
EF: Emission Factor
EFO: Equivalent Field Office
EFTC:  European Fluorocarbon
  Technical Committee
EGR Exhaust Gas Retircula-
  tion
EH: Redox Potential
EHC:   Environmental Health
  Committee
EHS:   Extremely  Hazardous
  Substance
El: Emissions Inventory
EIA:  Environmental Impact
  Assessment. Economic Impact
  Assessment
EIL: Environmental  Impair-
  ment Liability
EIRc Endangerment Information
  Report
EIR:  Environmental Impact
  Report
EIS:  Environmental Impact
  Statement
EIS: Environmental  Inventory
  System
EIS/AS: Emissions  Inventory
  System/Area Source
EIS/PS: Emissions  Inventory
  SystenVPoint Source
EKMA: Empirical Kinetic Mod-
  eling Approach
EL: Exposure Level
RT-T- Environmental Law Insti-
  tute
ELR: Environmental Law  Re-
  porter
EM: Electromagnetic Conduc-
  tivity
EMAP: Environmental Mapping
  • and ABsessment Program
EMAS: Enforcement Manage-
  ment and Accountability Sys-
  tem
EMR: Environmental Manage-
  ment Report
RMS- Enforcement Management
  System
EMSL:  Environmental  Moni-
  toring Support Laboratory
EMSL:  Environmental  Moni-
  toring Systems Laboratory
EMTS:  Environmental  Moni-
  toring Testing Site
EMTS:  Exposure  Monitoring
  Test  Site
EO: Ethylene Oxide
EOC:   Emergency  Operating
  Center
EOF:   Emergency  Operations
  Facility (RTP)
EOF: End Of Pipe
EOT:   Emergency  Operations
  Team
EP: Earth Protectors
EP: Environmental Profile. End-
  use  Product. Experimental
  Product Extraction Procedure
EPAA: Rnvinnrmnmtnl PrOgTBIQS
  Assistance Act
EPAAR: EPA Acquisition Regu-
  lation!
EPCRA: Emergency Prepared-
  ness and Community Right to
  Know Act
EPACASR: EPA Chemical Ac-
  tivities Status Report
EPCA: Energy Policy and Con-
  servation Act
EPD: Emergency Planning Dis-
  trict
EPI: Environmental Policy In-
  stitute
EPIC:  Environmental  Photo-
  graphic Interpretation Center

EPNL:  Effective  Perceived
  Noise Level       *
EPRI: Electric Power Research
  Institute
EFTC: Extraction  Procedure
  Toxicity Characteristic
Eft Electrical Resistivity
ERA:   Economic  Regulatory
  Agency
ERAMS: Environmental Radi-
  ation  Ambient  Monitoring
  System
ERC:   Emergency  Response
  Commission
ERC:   Emissions   Reduction
  Credit
ERC:  Environmental Research
  Center
ERCS: Emergency Response
  Cleanup Services
ERDA: Energy Research and
  Development Administration
ERD&DAA:   Environmental
  Research,  Development and
  Demonstration Authorization
  Act
ERL:  Environmental Research
  Laboratory
ERNS: Emergency Response
  Notification System
ERPi  Enforcement Response
  Policy
ERT:   Emergency  Response
  Team
ERTAQ: ERT Air Quality Model
ES: Enforcement Strategy.
ESA:  Endangered Species Act.
  Environmentally  Sensitive
  Area
ESC: Endangered Species Com-
  mittee
ESCA: Electron Sp
  for Chemical Analysis
ESCAP: Economic and  Social
  Commission for Asia and the
  Pacific
ESECA: Energy  Supply and
  Environmental Coordination
  Act
ESH: Environmental Safety and
  Health
ESP: Electrostatic Precipitators
ET: Emissions Trading
ETP: Emissions Trading Policy
ETS:  Environmental  Tobacco
  Smoke
EUP:  End-Use Product
EUP:  Experimental Use Permit
EWCC: Environmental Work-
  force Coordinating Committee
EXAMS:  Exposure  Analysis
  Modeling System
 FACA:  Federal  Advisory
   Committee Act
 FAN: Fixed Account Number
 FATES: FIFRA and TSCA En-
   forcement System
 FBC: Fluidized Bed Combustion
. FCC: Fluid Catalytic Converter
 FCCU: Fluid Catalytic Cracking
   Unit
 FCO:   Federal   Coordinating
   Officer (in disaster areas)
 FCO: Forms Control Officer
 FDF: Fundamentally Different
   Factors
 FDL: Final Determination Let-
   ter
 FDO: Fee Determination Offi-
   cial
 FE: Fugitive Emissions
 FEDS:  Federal  Energy Data
   System
 FEFx: Forced Expiratory Flow
 FEIS:  Fugitive Emissions In-
   formation System
 FEL: Frank Effect Level
 FEPCA: Federal Environmental
   Pesticide Control Act; enacted
   as amendments to FIFRA.
 FERC: Federal Energy Regula-
   tory Commission
 FES: Factor Evaluation System
 FEV: Forced Expiratory Volume
 FEV1: Forced Expiratory Vol-
   ume—one second
 FEV1: Front End Volatility In-
   dex
 FF: Federal Facilities
 FFAR: Fuel and Fuel Additive
   Registration
 FFDCA: Federal  Food,  Drug,
   and Cosmetic Act
 FFF: Firm Financial Facility
 FFFSG:  Fossil-Fuel-Fired
   Steam Generator
 FFIS:  Federal Facilities Infor-
   mation System
 FFP: Firm Fixed Price
 FGD: Flue-Gas Desulfurization
 FID: Flame lonization Detector
 FIFRA:  Federal  Insecticide,
   Fungicide, and Rodentiride
   Act
 FIM: Friable Insulation Materi-
   al
 FINDS: Facility Index System
 FTP: Final Implementation Plan

 FTPS: Federal Information Pro-
   cedures System
 FIT. Field Investigation Team
 FLETC: Federal Law Enforce-
   ment Training Center
 FLM: Federal Land Manager
 FLP: Flash Point
 FLPMA: Federal Land  Policy
   and Management Act
 FMAPl Financial Management
   Assistance Project
 F/M: Food  to Microorganism
   Ratio
 FML: Flexible Membrane Liner
 FMP.   Facility   Management
   Plan
 FMP:  Financial  Management
   Plan

-------
 46
 FMS:  Financial ' Management
   System
 FMVCP: Federal Motor Vehicle
   Control Program
 FOE: Friends Of the Earth
 FOIA: Freedom Of Information
   Act
 FOISD:  Fiber  Optic Isolated
   Spherical Dipole Antenna
 FONSI: Finding Of No Signifi-
   cant Impact
 FORAST:  Forest Response  to
   Anthropogenic Stress
. FP: Fine Particulate
 FPA: Federal Pesticide Act
 FPAS:  Foreign Purchase Ac-
   knowledgement Statements
 FPD: Flame Photometric Detec-
   tor
 FPEIS: Fine Particulate Emis-
   sions Information System
 FPM: Federal Personnel Manu-
   al
 FPPA:  Federal Pollution Pre-
   vention Act
 FPR: Federal Procurement Reg-
   ulation
 FPRS:  Federal Program Re-
   sources Statement
 FPRS:  Formal  Planning  and
   Supporting System
 FR:  Federal   Register.  Final
   Rulemaking
 FRA: Federal Register Act
 FREDS: Flexible Regional Emis-
   sions Data System
 FRES: Forest  Range Environ-
   mental Study
 FRM: Federal Reference Meth-
   ods
 FRN: Federal  Register  Notice.
   Final Rulemaking Notice
 FRS: Formal Reporting System
 FS: Feasibility Study
 FSA: Food Security Act
 FSS: Facility Status Sheet
 FSS: Federal Supply Schedule
 FTP:  Federal  Test  Procedure
   (for motor .vehicles)
 FTS: File Transfer Service
 FTTS: FIFRA/TSCA Tracking
   System
 FUA: Fuel Use Act
 FURS:  Federal  Underground
   Injection Control Reporting
   System
 FVMP: Federal Visibility Moni-
   toring Program
 FWCA: Fish and Wildlife Coor-
   dination Act
 FWPCA: Federal Water Pollu-
   tion and Control  Act (aka
   CWA). Federal Water Pollu-
   tion and Control Administra-
   tion
  GAAP: Generally Accepted Ac-
    counting Principles
  GAC: Granular Activated Car-
    bon
  GACT: Granular Activated Car-
    bon Treatment
  GC/MS:  Gas  Chromatograph/
    Mass Spectograph
  GCWR:   Gross   Combination
    Weight Rating
GDE: Generic Data Exemption
GEI: Geographic Enforcement
  Initiative
GEMS: Global Environmental
  Monitoring System
GEMS:  Graphical  Exposure
  Modeling System
GEP: Good Engineering Practice
GFF: Glass  Fiber Filter
GFO: Grant Funding Order
GFP:  Government-Furnished
  Property
GIGS:  Grant Information and
  Control System
GIS:  Geographic  Information
  Systems
GIS: Global Indexing System
GLC: Gas Liquid Chromatogra-
  phy
GLERL: Great Lakes Environ-
  mental Research Laboratory
GLNPO: Great Lakes National
  Program  Office
GLP: Good Laboratory Practices
GLWQA:  Great Lakes  Water
  Quality Agreement
GMCC: Global Monitoring for
  Climatic Change
G/MI: Grams per mile
GOCO:  Government-Owned/
  Contractor-Operated
GOGO:  Government-Owned/
  Government-Operated
GOP: General Operating Proce-
  dures
GOPO:  Government-Owned/
  Privately-Operated
GPAD: Gaions-per-acre per-day
GPG: Grams-per-Gallon
GPR Ground-Penetrating Ra-
  dar
GPS: Groundwater  Protection
  Strategy
Gft Grab Radon Sampling
GRCDA:  Government  Refuse
  Collection and Disposal Asso-
  ciation
GRGL: Groundwater  Residue
  Guidance Level
GTN: Global Trend Network
GTR Government Transporta-
  tion Request
GVP Gasoline Vapor Pressure
GVW: Grow Vehicle Weight
GVWR: Gross Vehicle Weight
  Rating
GW: Grab Working-Level Sam-
  pling. Groundwater
GWM: Groundwater Monitoring
GWPS: Groundwater Protection
  Standard
GWPS: Groundwater Protection
  Strategy

 H
HA: Health Advisory
HAD: Health Assessment Docu-
   ment
 HAP: Hazardous Air Pollutant
 HAPEMS:  Hazardous Air Pol-
   lutant Enforcement Manage-
   ment System
 HAPPS:  Hazardous Air  Pollut-
   ant Prioritization System
 HATREMS:  Hazardous  and
   Trace Emissions System
HAZMAT: Hazardous Materials
HAZOP: Hazard and Operabili-
  ty Study
HC: Hazardous Constituents
HC: Hydrocarbon
HCCPD:  Hexachlorocyclo-
  pentadiene
HCP: Hypothermal Coal Process
HDD: Heavy-Duty Diesel'
HDE: Heavy-Duty Engine
HDG:  Heavy-Duty  Gasoline-
  Powered Vehicle
HDPE: High Density Polyethyl-
  ene
HOT: Highest Dose Tested in a
  study. Heavy-Duty Truck
HDV: Heavy-Duty Vehicle
HEAL: Human Exposure As-
  sessment Location
HECC: House Energy and Com-
  merce Committee
HEI: Health Effects Institute
HEM: Human Exposure Model-
  ing
HEPA: High-Efficiency Particu-
  late Air
HERS: Hyperion Energy Re-
  covery System
HHE; Human  Health and the
  Environment
HHV: Higher Heating Value
HI: Hazard Index
HI-VOL: High-Volume Sampler
HIWAY: A Line Source Model
  for Gaseous Pollutants
HLRW: High Level Radioactive
  Waste
HMIS:  Hazardous  Materials
  Information System
HMS: Highway Mobile Source
HMTA: Hazardous  Materials
  Transportation Act
HMTft Hazardous  Materials
  Transportation Regulations
HOC:  Halogenated   Organic
  Carbons
HON:   Hazardous  Organic
  NESHAP
HOV: High-Occupancy Vehicle
HP: Horse Power
HPLC: High-Performance Liq-
  uid Chromatography
HPV: High Priority Violator
HQCDO:  Headquarters   Case
  Development Officer
HRS: Hazardous Ranking Sys-
  tem
HRUP: High-Risk Urban Prob-
  lem
HSDB: Hazardous  Substance
   DataBase
HSL: Hazardous Substance List
HSWA: Hazardous  and  Solid
   Waste Amendments
HT: Hypothermally Treated
HTP:  High  Temperature and
   Pressure
 HVIO: High Volume Industrial
   Organic*
 HW: Hazardous Waste
 HWDMS:  Hazardous   Waste
   Data Management System
 HWGTF:   Hazardous   Waste
   Groundwater Task Force
 HWGTF:   Hazardous   Waste
   Groundwater Test Facility
HWLT: Hazardous Waste Land
  Treatment
HWM: Hazardous  Waste Man-
  agement
HWRTF: Hazardous Waste Re-
  strictions Task Force
HWTC: Hazardous Waste Treat-
  ment Council

I
I/A: Innovative/Alternative
LA: Interagency Agreement
IAAC: Interagency Assessment
  Advisory Committee
LAG: Interagency Agreement
IAP: Incentive Awards Program.
  Indoor Air Pollution
IARC: International Agency for
  Research on Cancer
LATDB: Interim Air Toxics Data
  Base
IBT: Industrial Biotest Labora-
  tory
ICAIR: Interdisciplinary Plan-
  ning and Information Re-
  search
ICAP: Inductively Coupled Ar-
  gon Plasma
ICB:  Information  Collection
  Budget
ICBN:  International  Commis-
  sion on the.Biological Effects
  of Noise
ICE:  Industrial  Combustion
  Emissions  Model.   Internal
  Combustion Engine
ICP: Inductively Coupled Plas-
  ma
ICR Information Collection Re-
  quest
ICRE: Ignitability, Corrosivity,
  Reactivity, Extraction
ICRP:  International  Commis-
  sion on Radiological Protec-
  tion
ICRU: International  Commis
  sion of . Radiological  Units
  and
  Measurements
ICS: Incident  Command Sys-
  tem.
ICS:  Institute   for  Chemical
  Studies.
ICS: Intermittent Control Strat-
  egies.
ICS; Intermittent Control  Sys
  tern
ICWM: Institute  for Chemical
  Waste Management
IDLH: Immediately Dangerous
  to Life and Health
IEB: International Environment
  Bureau
IEMP: Integrated Environmen-
  tal Management Project
IBS: Institute for Environmen-
  tal Studies
IFB: Invitation  for Bid
 IFCAM: Industrial Fuel Choice
   Analysis Model
 IFIS: Industry File Information
   System
 IFPP. Industrial  Fugitive Pro-
   cess Particulate
 IFMS:  Integrated   Financial
   Management System
 IGCC: Integrated Gasification
 Combined Cycle

-------
                                                                                                                  47
IGCI: Industrial Gas Cleaning
  Institute
IIS: Inflationary Impact State-
  ment
LJC: International Joint Com-
  mission (on Great Lakes)
l/M: Inspection/Maintenance
IMM:  Intersection   Midblock
  Model
IMPACT:  Integrated  Model of
  Plumes and Atmosphere in
  Complex Terrain
IMPROVE: Interagency Moni-
  toring  of  Protected  Visual
  Environment
INPUFF:  Gaussian  Puff  Dis-
  persion Model
INT: Intermittent
IOB: Iron Ore Benefication
IOU: Input/Output Unit
IP: Inhalable Particles
IPM: Inhalable Particulate Mat-
  ter. Integrated Pest Manage-
  ment
IPP: Implementation  Planning
  Program. Integrated Plotting
  Package. Inter-media Priority
  Pollutant (document)
IPCS: International Program on
  Chemical Safety
IPP: Independent Power  Pro-
  ducer
IRG: Interagency Review Group
IRLG:  Interagency Regulatory
Liaison Group (Composed  of
EPA, CPSC, FDA, and OSHA)
IRIS:  Instructional  Resources
  Information System. Integrat-
  ed Risk Information System
IRM:   Intermediate  Remedial
  Measures
IRMC: Inter-Regulatory Risk
  Management Council
IRP:  Installation  Restoration
  Program
IRPTC: International Register
  of Potentially Toxic Chem-
  icals
IRR Institute of  Resource  Re-
  covery
IRS: International Referral Sys-
  tems
IS: Interim Status
ISAM:  Indexed Sequential File
  Access Method
ISC: Industrial Source Complex
ISCL: Interim Status Compli-
  ance Letter
ISCLT: Industrial Source Com-
  plex Long Term Model
ISCST: Industrial Source Com-
  plex Short Term Model
ISD: Interim Status Document
ISE: Ion-specific electrode
ISMAP: Indirect Source Model
  for Air Pollution
ISPF: (IBM) Interactive System
  Productivity Facility
ISS: Interim Status Standards
FTC: Interagency Testing Com-
  mittee
IUR Inventory Update Rule
IWC: In-Stream Waste Concen-
  tration
IWS: Ionizing Wet Scrubber
JAPCA: Journal of Air Pollution
  Control Association
JCL: Job Control Language
JEC: Joint Economic Committee
JECFA: Joint Expert Committee
  of Food Additives
JLC: Justification for Limited
  Competition
JMPR: Joint Meeting on Pesti-
  cide Residues
JNCP:  Justification  for Non-
  Competitive Procurement
JOFOC: Justification for Other
  Than Full and Open
  Competition
JPA: Joint Permitting  Agree-
.  ment
JSD: Jackson Structured Design
JSP: Jackson Structured  Pro-
  gramming
JTU: Jackson Turbidity Unit
LAA: Lead Agency Attorney
LADD: Lowest Acceptable Daily
  Dose
LAER Lowest Achievable Emis-
  sion Rate
LAI: Laboratory Audit Inspec-
  tion
LAMP: Lake Acidification Miti-
  gation Project
LC: Lethal Concentration. Liq-
  uid Chromatography
LCD: Local Climatological Data
LCL: Lower Control Limit
LCM: Life Cycle Management
LCRS: Leachate Collection and
  Removal System
LD: Land Disposal. Light Duty
LD LO: The lowest dosage of a
  toxic substance that kills test
  organisms.
LDC: London Dumping Conven-
  tion
LDCRS:  Leachate Detection,
  Collection, and Removal Sys-
  tem
LDD: Light-Duty Diesel
LDIP: Laboratory Data Integri-
  ty Program
LDft  Land  Disposal Restric-
  tions
LDRTF: Land Disposal Restric-
  tions Task Force
LDS: Leak Detection System
LOT:   Lowest Dose  Tested.
  Light-Duty Truck
LDV: Light-Duty Vehicle
T.RTJ Lowest Effect Level. Low-
  er Explosive Limit
LEP:  Laboratory   Evaluation-
  Program
LEPC: Local Emergency Plan-
  ning Committee
LERC: Local Emergency Re-
  sponse Committee
LFL: Lower Flammability Limit
LGR Local Governments Reim-
  bursement Program
LI: Langelier Index
LIDAft Light Detection  and
  Ranging
LIMB: Limestone-Injection Mul-
  ti-Stage Burner
LLRW: Low Level Radioactive
  Waste
LMFBR:  Liquid Metal  Fast
  Breeder Reactor
LOAEL:  Lowest-Observed-Ad-
verse-Effect-Level
LUIS:  Label Use Information
  System

M
MAPSIM: Mesoscale  Air Pollu-
  tion Simulation Model
MBAS:  Methyiene-Blue-Active
Substances
MEP: Multiple Extraction Pro-
  cedure
MOE: Margin Of Exposure
MOS: Margin of Safety
MP: Manufacturing-use Product
MP: Melting Point
MFN: Maximum Possible Num-
ber
MRF: Materials Recovery Facili-
  ty
MRID:  Master  Record Identifi-
  cation number
MRL: Maximum-Residue Limit
  (Pesticide Tolerance)
MSW: Municipal Solid Waste
MTD: Maximum Tolerated Dose
MUP: Manufacturing-Use Prod-
  uct
MUTA: Mutagenicity

N
NCWS: Non-Community Water
System
NETA: National Environmental
Training Association
NFRAP: No Further R«m«Hi«l
  Action Planned
NICT: National Incident Coordi-
  nation Team
NIOSH: National Institute of
Occupational Safety and Health
NIPDWR   National  Interim
Primary Drinking Water Regu-
lations
NISAC:   National   Industrial
  Security Advisory Committee
NO A: Notice of Arrival
NOAC:  Nature of Action Code
NOAEL: No Observable Adverse
Effect Level
NPHAR  National  Pesticide
  Hazard Assessment Program
NSDWft  National   Secondary
  Drinking Water Regulations
NSEC:  National System  for
  Emergency Coordination
NSER  National System  for
  Emergency Preparedness
NSR New Source Review
NTP: National  Toxicology Pro-
gram
NTNCWS: Non-Transient Non-
Community Water System
NTU: Nephlometric  Turbidity
Unit


o
OCD:  Offshore and Coastal
  Dispersion
OF: Optional Form
OLTS: On Line Tracking Sys-
  tem
O&M: Operations and Mainte-
  nance
ORM: Other Regulated Material
ORP: Oxidation-Reduction  Po-
  tential
PA1: Performance Audit Inspec-
  tion (CWA)
PAI: Pure Active' Ingredient
  compound
PAM: Pesticide Analytical Man-
  ual
PAT: Permit Assistance Team
  (RCRA)
PATS: Pesticide Action Tracking
  System
PATS:   Pesticides  Analytical
  Transport Solution
PBA: Preliminary Benefit Anal-
  ysis (BEAD)
PCA:   Principle  Component
  Analysis
PCM: Phase Contrast  Micros-
  copy
PCN: Policy Criteria Notice
PCO: Pest Control Operator
PDCI: Product Data Call-In
PFCRA: Program Fraud Civil
  Remedies Act
PHC: Principal Hazardous Con-
  stituent
PHSA:  Public Health  Service
  Act
PI: Preliminary Injunction. Pro-
  gram Information
PIC: Products  of  Incomplete
  Combustion
PIGS: Pesticides in Groundwa-
  ter Strategy
PIMS: Pesticide Incident Moni-
  toring System
PIN: Pesticide Information Net-
  work
PIN: Procurement Information
  Notice
PIP: Public  Involvement Pro-
  gram
PIPQUIC: Program Integration
  Project Queries Used in Inter-
  active Command
PIRG: Public Interest Research
  Group
PIRT: Pretreatinent Implemen-
  tation Review Task Force
PITS:  Project  Information
  Tracking System
PLJRRA:   Pollution   Liability
  Insurance and Risk Retention
  Act
PLM: Polarized Light  Micros-
  copy
PLUVUE: Plume Visibility Mod-
  el
PM: Particulate Matter
PM10:  Particulate   Matter
  (nominally 10m and less)
PM15:   Particulate   Matter
  (nominally 16m and leas)
PMEL: Pacific Marine Environ-
  mental Laboratory
FMN:  Premanufacture  Notifi-
  cation
PMNP:  Premanufacture  Noti-
  fication Form

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48
PMR- Pollutant Mass Rate
PMRS:  Performance Manage-
  ment and Recognition System
PMS:  Program  Management
  System
PNA:  Polynuclear  Aromatic
  Hydrocarbons
PO: Project Officer
POC: Point Of Compliance
POE: Point Of Exposure
POGO: Privately-Owned/ Gov-
  ernment-Operated
POHC: Principal Organic Haz-
  ardous Constituent
POI: Point Of Interception
POLREP:Pollution Report
POM: Particulate Organic Mat
  ter. Polycyclic Organic Matter •
FOR: Program of Requirements
POTW: Publicly Owned Treat-
  ment Works
POV: Privately Owned Vehicle
PP: Program Planning
PPA: Planned Program Accom-
  plishment
PPB: Parts Per Billion
PPIC: Pesticide Programs Infor-
  mation Center
PPIS: Pesticide Product Infor-
  mation System
PPM/PPB:  Parts per  million/
  parts per billion
PPMAP: Power Planning Model-
  ing Application Procedure
PPSP: Power Plant Siting Pro-
  gram
PPT: Parts Per Trillion
PPTH: Parts Per Thousand
PQUA: Preliminary Quantita-
  tive Usage Analysis
PR- Preliminary Review
PRAj Paperwork Reduction Act
PRA: Planned Regulatory Ac'
  tion
PRATS: Pesticides  Regulatory
  Action Tracking System
PRC: Planning  Research Cor-
  poration
PRI: Periodic Reinvestigation
PRM:  Prevention   Reference
  Manuals
PRN:  Pesticide  Registration
  Notice
PRP:  Potentially  Responsible
  Party
PRZM: Pesticide  Root  Zone
  Model
PS: Point Source
PSAM: Point Source Ambient
  Monitoring
PSC: Program Site Coordinator
PSD:  Prevention of Significant
  Deterioration
PSES: Pretreatment Standards
  for ESri«*ir»g Sources
PSI: Pollutant Standards Index
PSI:  Pounds Per Square Inch
PSI:  Pressure Per Square Inch
PSIG: Pressure Per Square Inch
  Gauge
PSM: Point Source Monitoring
PSNS: Pretreatment Standard*
  for New Sources
PSU: Primary Sampling Unit
PTDIS: Single Stack Meteoro-
  logical   NIodel   in  EPA
  UNAMAP Series
PTE: Potential to Emit
PTFE:  Polytetrafluoroethylene
  (Teflon)
PTMAX: Single Stack Meteoro-
  logical   Model   in  EPA
  UNAMAP series
PTPLU: Point Source Gaussian
  Diffusion Model
PUC: Public Utility Commission
PV: Project Verification
PVC: Polyvinyl Chloride
PWS:   Public Water  Supply/
  System
PWSS:  Public Water Supply
  System
QAC: Quality Assurance Coordi-
  nator.
QA/QC:  Quality   Assistance/
  Quality Control
QAMIS:  Quality  Assurance
  Management and Information
  System
QAO: Quality Assurance Officer
QAPP: Quality Assurance Pro-
  gram (or Project) Plan
QAT: Quality Action Team
QBTU:   Quadrillion   British
  Thermal Units
QC: Quality Control
QCA: Quiet Communities Act
QCI: Quality Control Index
QCP: Quiet  Community  Pro-
  gram
QNCR  Quarterly  Noncompli-
  ance Report
QUA: Qualitative  Use Assess-
  ment
QUIPE: Quarterly Update for
  Inspector in  Pesticide En-
  forcement
RA:  Reasonable  Alternative.
  Regulatory   Alternatives.
  Regulatory Analysis. Remedi
  al Action. Resource  Alloca
  tion.  Risk  Analysis.  Risk
  Assessment
RAATS:  RCRA  Administrate
  Action Tracking System
RAG: Radiation Advisory Com-
  mittee
RAC: Regional Asbestos  Coor-
  dinator
RAC: Response Action Coordi-
  nator
RACM:  Reasonably  Available
  Control Measures
RACT:   Reasonably  Available
  Control Technology
RAD: Radiation Adsorbed Dose
  (unit of measurement of radi-
  ation absorbed by humans)
RADM:  Random Walk Advec-
  tion and Dispersion Model
RADM:  Regional Acid Deposi-
  tion Model
RAM: Urban Air Quality Model
  for Point and Area Source in
  EPA UNAMAP Series
RAMP: Rural Abandoned Mine
  Program
RAMS: Regional Air Monitoring
  System
RAP: Radon Action Program
RAP: Reregistration Assessment
  Panel
RAP: Remedial Accomplishment
  Plan
RAP: Response Action Plan
RAPS:  Regional Air  Pollution
  Study
RARG:  Regulatory   Analysis
  Review Group
RAS: Routine Analytical Service
RAT: Relative Accuracy Test
RB: Request for Bid
RC: Responsibility Center
RCC:  Radiation  Coordinating
  Council
RCDO: Regional Case Develop-
  ment Officer
RCO: Regional Compliance Offi-
cer
RCP: Research Centers Program
RCRA:  Resource Conservation
  and Recovery Act
RCRIS: Resource Conservation
  and  Recovery  Information
  System
RD/RA: Remedial  Design/ Re-
  medial Action
R&D: Research and  Develop-
  ment         '
RD&D: Research, Development
  and Demonstration
RDF: Refuse-Derived Fuel
rDNA: Recombinant DNA
RDU: Regional Decision Units
RDV: Reference Dose Values
RE: Reasonable Efforts
RE: Reportable Event
REAP:  Regional  Enforcement
  Activities Plan
REE: Rare Earth Elements
REEP: Review of Environmen-
  tal Effects of Pollutants
REM   (Roentgen  Equivalent
  Man)
REM/FIT: Remedial/Field Inves-
  tigation Team
REMS:  RCRA  Enforcement
  Management System
REP: Reasonable Efforts Pro-
  gram
REPS: Regional Emissions Pro-
  jection System
RESOLVE: Center for Environ-
  mental Conflict Resolution
RF: Response Factor
RFA: Regulatory Flexibility Act
RFB: Request for Bid
RFD: Reference Dose Values
RFI: Remedial Field Investiga-
  tion
RFP: Reasonable Further Pro-
  grams. Request for Proposal
RHRS: Revised Hazard Ranking
  System
RI: Reconnaissance Inspection
RI: Remedial Investigation
RIA: Regulatory Impact Anal-
  ysis
RIA: Regulatory Impact Assess-
  ment
RIC: Radon Information Center
RICC: Retirement  Information
  and Counseling Center
RICO: Racketeer Influenced and
  Corrupt Organizations Act
RI/FS: Remedial  Information/
  Feasibility Study
RIM: Regulatory Interpretation
  Memorandum
RIN:   Regulatory  Identifier
  Number
RIP:  RCRA   Implementation
  Plan
RISC: Regulatory Information
  Service Center
RJE: Remote Job Entry
RLL: Rapid and Large Leakage
  (Rate)
RMCL:  Recommended  Maxi-
  mum   Contaminant  Level
  (this phrase being discontin-
  ued in favor of MCLG)
RMDHS:  Regional Model Data
  Handling System
RMIS: Resources Management
  Information System
RNA: Ribonucleic Acid
ROADCHEM: Roadway Version
  that Includes Chemical Reac-
  tions of BI,NO2, andO3
ROADWAY: A Model to Predict
  Pollutant  Concentrations
  Near a Roadway
ROC: Record Of Communication
RODS: Records  Of  Decision
  System
ROG: Reactive Organic Gases
ROLLBACK:  A   Proportional
  Reduction Model
ROM: Regional Oxidant Model
ROMCOE:  Rocky  Mountain
  Center on Environment
ROP: Regional Oversight Policy
ROPA: Record Of Procurement
  Action
RP: Radon Progeny Integrated
  Sampling.  Respirable
  Participates.  Responsible
  Party
RPAR Rebuttable Presumption
  Against Registration
RPM:  Reactive Plume Model.
  Remedial Project Manager
RQ: Reportable Quantities
RRC: Regional Response Center
RRT: Regional Response Team
RRT:   Requisite  Remedial
  Technology
RS: Registration Standard
RSCC: Regional Sample Control
  Center
RSD: Risk-Specific Dose
RSE: Removal Site Evaluation
RTCM: Reasonable  Transpor-
  tation Control Measure
RTDM: Rough Terrain Diffusion
  Model
RTECS: Registry of Toxic  Ef-
  fects of Chemical Substances
RTM: Regional Transport Model
RUP: Restricted Use Pesticide
RVP: Reid Vapor Pressure
RWC: Residential Wood Com-
  bustion
S&A:  Sampling and Analysis.
  Surveillance and Analysis
SAB: Science Advisory Board
SAC: Suspended and Cancelled
  Pesticides

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                                                                                                                  49
SAEWG:  Standing Air Emis-
  sions Work Group
SAIC: Spetial-Agenta-In-Charge
SAIP: Systems Acquisition and
  Implementation Program
SAMWG: Standing Air Moni-
  toring Work Group
SANE:  Sulfur  and  Nitrogen
  Emissions
SANSS: Structure and Nomen-
  clature Search System
SAP. Scientific Advisory Panel
SAR  Start Action  Request.
  Structural Activity  Relation-
  ship (of a qualitative assess-
  ment)  .
SARA: Superfund Amendments
  and Reauthorization Act- of,
  1986
SAROAD: Storage and Retrieval
  Of Aerometric Data
SAS: Special Analytical Service.
  Statistical Analysis System
SASS: Source Assessment Sam-
  pling System
SAV: Submerged Aquatic Vege
  tation
SC: Sierra Club
SOAP: Superfund Consolidated
  Accomplishments Plan
SCBA: Self-Contained Breath-
  ing Apparatus
SCC: Source Classification Code
SCD/SWDC: Soil  or  Soil and
  Water Conservation District
SCFM: Standard Cubic Feet Per
  Minute
SCLDF: Sierra Club Legal De-
  fense Fund
SCR: Selective Catalytic Reduc-
  tion
SCRAM:  State  Consolidated
  RCRA Authorization Manual
SCRC: Superfund Community
  Relations Coordinator
SCS:  Supplementary Control
  Strategy/System
SCSA: Soil Conservation Society
  of America
SCSP:  Storm  and  Combined
  Sewer Program
SCW: Supercritical Water Oxi-
  dation
SDC: Systems Decision Plan
SDWA:  Safe  Drinking Water
  Act
SEA:  State   Enforcement
  Agreement
SEA; State/EPA Agreement
SEAM: Surface, Environment,
  and Mining
SEAS: Strategic Environmental
  Assessment System
SEIA:  Socioeconomic Impact
  Analysis
SEM: Standard Error  of the
  Means
SEP: Standard Evaluation Pro-
  cedures
SEPWC: Senate Environment
  and Public Works Committee
SERC: State Emergency Plan-
  ning Commission
SES:   Secondary   Emissions
  Standard
SETS: Site Enforcement Track-
  ing System
SF: Standard Form. Superfund
SFA: Spectral Flame Analyzers
SFDS:  Sanitary Facility  Data
  System
SFFAS: Superfund  Financial
  Assessment System
SFIREG: State  FIFRA Issues
  Research  and  Evaluation
  Group
SFS: State Funding Study
SHORTZ: Short Term Terrain
  Model
SHWL:  Seasonal High Water
  Level
SI:   International  System  of
  Units. Site Inspection. Sur-
  veillance  Index.  Spark  Igni-
  tion
SIC: Standard Industrial Classi-
  fication
SICEA: Steel Industry Compli-
  ance Extension Act
SIMS:   Secondary  Ion-Mass
  Spectrometry
SIP: State Implementation Plan
SITE:  Superfund  Innovative
  Technology Evaluation
SLAMS: State/Local  Air Moni-
  toring Station
SLSM: Simple Line Source Mod-
  el
SMART: Simple Maintenance of
  ARTS
SMCL:  Secondary  Maximum
Contaminant Level
SMCRA: Surface Mining Con-
  trol and Reclamation Act
SME: Subject Matter Expert
SMO:  Sample   Management
  Office
SMOA:  Superfund  Memoran-
  dum of Agreement
SMSA: Standard Metropolitan
  Statistical Area
SNA: System Network Architec-
  ture
SNAAQS:  Secondary National
  Ambient  Air  Quality  Stan-
  dards
SNAP: Significant Noncompli-
  ance Action Program
SNARL: Suggested No Advene
  Response Level
SNC: Significant Noncomplien
SNUR  Significant  New  Use
  Rule
SOC: Synthetic Organic Chem-
  icals
SOCMI:   Synthetic  Organic
  Chemicals  Manufacturing
  Industry
SOTDAT: Source Test Data
SOW: Scope Of Work
SPAR: Status of Permit Applica-
  tion Report
SPCC: Spill Prevention, Con-
  tainment, and Countermea-
  sure
SPE:  Secondary   Particulate
  Emissions
SPF: Structured Programming
  Facility
SPI: Strategic Planning Initia-
  tive
SPLMD: Soil-pore Liquid Moni-
  toring Device
SPMS:  Special  Purpose Moni-
  toring Stations
SPMS: Strategic Planning and
  Management System
SPOC: Single Point Of Contact
SPS: State Permit System
SPSS:  Statistical Package  for
  the Social Sciences
SPUR Software  Package  for
  Unique Reports
SQBE: Small Quantity Burner
  Exemption
SQG: Small Quantity Generator
SRAP:  Superfund   Remedial
  Accomplishment Plan
SRC: Solvent-Refined Coal
SRM: Standard Reference Meth-
  od
SRP: Special Review Procedure
SRR  Second  Round Review.
  Submission Review Record
SRTS: Service Request Tracking
  System
SS: Settleable Solids. Superfund
  Surcharge. Suspended Solids
SSA: Sole Source Aquifer
SSAC: Soil  Site  Assimilated
  Capacity
SSC: State Superfund Contracts
SSD: Standards Support Docu-
  ment
SSEIS: Standard Support and
  Environmental   Impact
  Statement. Stationary Source
  Emissions  and   Inventory
  System
SSI: Size Selective Inlet
SSMS: Spark Source Mass Spec-
  trometry
SSO: Source Selection Official
SSTS: Section Seven Tracking
  System
SSURO: Stop  Sale, Use and
  Removal Order
STAPPA: State and Territorial
  Air Pollution
STALAPCO: State  and  Local
  Air- Pollution  Control Offi-
  cials
STAR: Stability  Wind  Rose.
  State Acid Rain Projects
STEL: Short  Term Exposure
  Limit
STEM: Scanning Transmission-
  Electron Microscope
STN: Scientific and Technical
  Information Network
STORET: Storage and Retrieval
  of Water-Related Data
STP:  Sewage Treatment Plant.
  Standard Temperature and
  Pressure
SUP: Standard Unit of Process-
  ing
SURE: Sulfate Regional Experi-
  ment Program
SV: Sampling Visit
SW: Slow Wave
SWC: Settlement With Condi-
  tions
SWDA: Solid Waste Disposal
  Act
SWIE: Southern Waste  Infor-
  mation Exchange
SWMU: Solid  Waste Manage-
  ment Unit
SWTR Surface Water Treat-
  ment Rule.
SYSOP: Systems Operator
TAG:   Technical   Assistance
  Grant
TALMS: Tunable Atomic Line
  Molecular Spectroscopy
TAMS: Toxic Air  Monitoring
  System
TAMTAC: Toxic Air Monitoring
  System Advisory Committee
TAP: Technical Assistance Pro-
  gram
TAPDS: Toxic  Air Pollutant
  Data System
TAS:   Tolerance  Assessment
  System
TBT: Tributyltin
TC: Target Concentration. Tech-
  nical Center. Toxicity Charac-
  teristics. Toxic Concentration:
TCDD: Dioxin  (Tetrachlorodi-
  benzo-p-dioxin)
TCDF:  Tetrachlorodi-benzo-
  furans
TCE: Trichloroethylene
TCLP:  Total   Concentrate
  Leachate  Procedure. Toxicity
  Characteristic Leachate Pro-
  cedure
TCM:  Transportation  Control
  Measure
TCP:  Transportation  Control
  Plan.  Trichloroethylene.
  Trichloropropane
TCRI: Toxic Chemical Release
  Inventory
TD: Toxic Dose
TDS: Total Dissolved Solids
TEAM: Total Exposure Assess-
  ment Model
TEC:   Technical   Evaluation
  Committee
TEG: Tetraethylerie Glycol
TEGD: Technical Enforcement
  Guidance Document
TEM: Texas Episodic Model
TEP: Typical End-use Product.
  Technical Evaluation Panel
TERA: TSCA  Environmental
  Release Application
TES:  Technical Enforcement
  Support
TEXIN: Texas Intersection  Air
  Quality Model
TOO: Total Gross Output
TGAI:  Technical Grade of  the
  Active Ingredient
TCP: Technical Grade Product
THC: Total Hydrocarbons
THM: Trihalomethane
TI: Temporary Intermittent
TI: Therapeutic  Index
TIBL:  Thermal  Internal
  Boundary Layer
TIC:   Technical   Information
  Coordinator.   Tentatively
  Identified Compounds
TIM:   Technical   Information
  Manager
TIP: Transportation  Improve-
  ment Program
TIS: Tolerance Index System
TISE: Take It Somewhere Else
TTTC: Toxic Substance Control
   Act Interagency Testing Com-
   mittee
TLV: Threshold Limit Value
TLV-C: TLV-Ceiling

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50
TLV-STEL:  TLV-Short  Term
  Exposure Limit
TLV-TWA: TLV-Time Weighted
  Average
TMRC: Theoretical Maximum
  Residue Contribution
TNCWS:  Transient Non-Com-
munity Water System
TNT: Trinitrotoluene
TO: Task Order
TOA: Trace Organic Analysis
TOG:  Total Organic Carbon/
  Compound
TOX: Tetradichloroxylene
TP: Technical Product
TPC:  Testing  Priorities  Com-
  mittee
TPI: Technical Proposal Instruc-
  tions
TPQ: Threshold Planning Quan-
  tity
TPSIS:Transportation Planning
  Support Information System
TFTH: Triphenyltinhydroxide
TPY: Tons Per Year
TQM: Total Quality  Manage-
  ment
T-R: Transformer-Rectifier
TRC:  Technical Review  Com-
  mittee
TRD;  Technical Review  Docu-
  ment
TRI: Toxic Release Inventory
TRIP. Toxic Release Inventory
  Program
TRIS: Toxic Chemical  Release
  Inventory System
TRLN: Triangle  Research  Li-
  brary Network
TRO:  Temporary  Restraining
  Order
TSA: Technical Systems Audit
TSCA: Toxic Substances Control
  Act           '
TSCATS: TSCA Test Submis-
  sions Database'
TSCC: Toxic Substances Coordi-
  nating  Committee
TSD:  Technical Support  Docu-
  ment
TSDF: Treatment, Storage, and
  Disposal Facility
TSDG: Toxic Substances Dia-
  logue Group
TSI: Thermal System Insulation
TSM:  Transportation  System
  Management
TSO: Time Sharing Option
TSP Total Suspended Particu-
  lates
TSS: Total Suspended (non-fil-
  terable) Solids
TTFA: Target  Transformation
  Factor  Analysis
TTHM: Total Trihalomethane
TTO: Total Toxic Organics
TTY: Teletypewriter
TVA: Tennessee Valley Authori-
  ty
TWA: Time Weighted Average
TWS: Transient Water System ,
TZ: Treatment Zone

u
UAC: User Advisory Committee
UAM: Urban Airshed Model
UAO: Unilateral Administrative
  Order
UAPSP Utility Acid Precipita-
  tion Study Program
UAQI:  Uniform  Air  Quality
  Index
UARG: Utility Air  Regulatory
  Group
UCC: Ultra Clean Coal
UCCI:  Urea-Formaldehyde
Foam Insulation
UCL: Upper Control Limit
UDMH:  Unsymmetrical  Di-
  methyl Hydrazine
UEL: Upper Explosive Limit
UFL: Upper Flammability Limit
UIC:  Underground   Injection
  Control
UMTRCA:  Uranium  Mill Tail-
  ings Radiation Control Act
UNAMAP. Users' Network for
  Applied Modeling of Air Pol-
  lution
UNEP United Nations Environ-
  ment Program
USC: Unified Soil Classification
USDW: Underground Sources of
  Drinking Water
USFS:  United States  Forest
  Service
USP U.S. Pharmacopeia
UST:  Underground   Storage
  Tank
UTM:  Universal  Transverse
  Mercator
UTP  Urban  Transportation
  Planning
UV: Ultraviolet
UZM: Unaaturated Zone Moni-
  toring
VALLEY: Meteorological Model
  to Calculate Concentrations
  on Elevated Terrain
VCM: Vinyl Chloride Monomer
VE: Visual Emissions
VEO: Visible Emission Observa-
  tion   :
VHS: Vertical  and Horizontal
  Spread Model
VHT: Vehicle-Hours of Travel
VISTTA: Visibility WmiTnumt
  from Sulfur Transformation
  and Transport in the Atmo-
  sphere
VKT: Vehicle Kilometers Trav-
  eled
VMT: Vehicle Miles Traveled
VOC: Volatile Organic Com-
  pounds
VOS: Vehicle Operating Survey
VOST:  Volatile Organic Sam-
  pling Train
VP. Vapor Pressure
VSD: Virtually Safe Dose
VSI: Visual Site Inspection
VSS: Volatile Suspended Solids

w
WA: Work Assignment
WADTF:  Western Atmospheric
  Deposition Task Force
WAP: Waste Analysis Plan
WB: Wet Bulb
WCED: World  Commission on
  Environment  and  Develop-
  ment
WDROP:  Distribution Register
  of Organic Pollutants in Wa-
  ter
WENDB:  Water Enforcement
  National Data Base
WERL: Water Engineering Re-
  search Laboratory
WHO: World Health Organi-
  zation
WHWT: Water and Hazardous
  Waste Team
WICEM: World Industry Con-
  ference  on  Environmental
  Management
WL: Warning Letter
WL: Working Level (radon mea-
  surement)
WLA/TMDL: Wasteload Alloca-
  tion/Total  Maximum  Daily
  Load
WLM: Working Level Months
WMO:  World   Meteorological
  Organization
WPCF: Water Pollution Control
  Federation
WQS: Water Quality Standard
WRC: Water Resources Council
WRDA: Water Resources Devel-
  opment Act
WRI: World Resources Institute
WS: Work Status
WSF: Water Soluble Fraction
WSRA: Wild and Scenic Rivers
  Act
WSTB: Water  Sciences  and
  Technology Board
WSTP  Wastewater  Sewage
  Treatment Plant
WWEMA:  Waste and Waste-
  water Equipment  Manufac-
  turers Association
WWF: World Wildlife Fund
WWTPi Wastewater Treatment
  Plant
WWTU: Wastewater Treatment
  Unit
ZHE: Zero Headspace Extractor
ZOI: Zone Of Incorporation
ZRL: Zero Risk Level

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