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Glossary: A
Abandoned Well:
A well whose use has been permanently discontinued or which is
in a
state of such disrepair that it cannot be used for its intended purpose.
Abatement:
Reducing the degree or intensity of, or eliminating, pollution.
Abatement Debris:
Waste from remediation activities.
Absorbed Dose:
In exposure assessment, the amount of a substance that penetrates an
exposed organism's absorption barriers (e.g. skin, lung tissue,
gastrointestinal tract) through physical or biological processes. The
term is synonymous with internal dose.
Absorption:
The uptake of water, other fluids, or dissolved chemicals by a cell or
an organism (as tree roots absorb dissolved nutrients in soil).
Absorption Barrier:
Any of the exchange sites of the body that permit uptake of various
substances at different rates (e.g. skin, lung tissue, and
gastrointestinal-tract wall).
Accident Site:
The location of an unexpected occurrence, failure or loss, either at a
plant or along a transportation route, resulting in a release of
hazardous materials.
Acclimatization:
The physiological and behavioral adjustments of an organism to changes
in its environment.
Acid:
A corrosive solution with a pH less than 7.
Acid Aerosol:
Acidic liquid or solid particles small enough to become airborne. High
concentrations can irritate the lungs and have been associated with
respiratory diseases like asthma.
Acid Deposition:
A complex chemical and atmospheric phenomenon that occurs when emissions
of sulfur and nitrogen compounds and other substances are transformed by
chemical processes in the atmosphere, often far from the original
sources, and then deposited on earth in either wet or dry form. The wet
forms, popularly called "acid rain," can fall to earth as rain, snow, or
fog. The dry forms are acidic gases or particulates.
Acid Mine Drainage:
Drainage of water from areas that have been mined for coal or other
mineral ores. The water has a low pH because of its contact with
sulfur-bearing material and is harmful to aquatic organisms.
Acid Neutralizing Capacity:
Measure of ability of a base (e.g. water or soil) to resist changes in
pH.
Acidic:
The condition of water or soil that contains a sufficient amount of acid
substances to lower the pH below 7.0.
Action Levels:
In the Superfund program, the existence of a contaminant concentration
in the environment high enough to warrant action or trigger a response
under SARA and the National Oil and Hazardous Substances Contingency
Plan. The term is also used in other regulatory programs.
Activated Carbon:
A highly adsorbent form of carbon used to remove odors and toxic
substances from liquid or gaseous emissions. In waste treatment, it is
used to remove dissolved organic matter from waste drinking water. It is
also used in motor vehicle evaporative control systems.
Activated Sludge:
Product that results when primary effluent is mixed with bacteria-laden
sludge and then agitated and aerated to promote biological treatment,
speeding the breakdown of organic matter in raw sewage undergoing
secondary waste treatment.
Activator:
A chemical added to a pesticide to increase its activity.
Active Ingredient:
In any pesticide product, the component that kills, or otherwise
controls, target pests. Pesticides 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 re-inspection required by the Asbestos
Hazard Emergency Response Act (AHERA).
Acute Effect:
An adverse effect on any living organism which results in severe
symptoms that develop rapidly; symptoms often subside after the exposure
stops.
Acute Exposure:
A single exposure to a toxic substance which may result in severe
biological harm or death. Acute exposures are usually characterized as
lasting no longer than a day, as compared to longer, continuing exposure
over a period of time.
Acute Toxicity:
The ability of a substance to cause severe biological harm or death soon
after a single exposure or dose. Also, any poisonous effect resulting
from a single short-term exposure to a toxic substance.
Adaptation:
Changes in an organism's physiological structure or function or habits
that allow it to survive in new surroundings.
Add-on Control Device:
An air pollution control device such as carbon absorber or incinerator
that reduces the pollution in an exhaust gas. The control device usually
does not affect the process being 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:
A legal document signed by a regulatory agency such as USEPA directing
an individual, business, or other entity to take corrective action or
refrain from an activity. It describes the violations and actions to be
taken, and can be enforced in court. Such orders may be issued, for
example, as a result of an administrative complaint whereby the
respondent is ordered to pay a penalty for violations of a statute.
Administrative Order On Consent:
A legal agreement signed by a regulatory agency such as USEPA and an
individual, business, or other entity through which the violator agrees
to pay for correction of violations, take the required corrective or
cleanup actions, or refrain from an activity. It describes the actions
to be taken, may be subject to a comment period, applies to civil
actions, and can be enforced in court.
Administrative Procedures Act:
A law that spells out procedures and requirements related to the
promulgation of regulations.
Administrative Record:
All documents which USEPA considered or relied on in selecting the
response action at a Superfund site, culminating in the record of
decision for remedial action or, an action memorandum for removal
actions.
Adsorption:
Removal of a pollutant from air or water by collecting the pollutant on
the surface of a solid material; e.g., an advanced method of treating
waste in which activated carbon removes organic matter from waste-water.
Advanced Treatment:
A level of wastewater treatment more stringent than secondary treatment;
requires an 85-percent reduction in conventional pollutant concentration
or a significant reduction in non-conventional pollutants. Sometimes
called tertiary treatment.
Advanced Wastewater Treatment:
Any treatment of sewage that goes beyond the secondary or biological
water treatment stage and includes the removal of nutrients such as
phosphorus and nitrogen and a high percentage of suspended solids. (See
primary, secondary treatment.)
Adverse Effects Data:
FIFRA requires a pesticide registrant to submit data to USEPA on any
studies or other information regarding unreasonable adverse effects of a
pesticide at any time after its registration.
Advisory:
A non-regulatory document that communicates risk information to those
who may have to make risk management decisions.
Aerated Lagoon:
A holding and/or treatment pond that speeds up the natural process of
biological decomposition of organic waste by stimulating the growth and
activity of bacteria that degrade organic waste.
Aeration:
A process which promotes biological degradation of organic matter in
water. The process may be passive (as when waste is exposed to air), or
active (as when a mixing or bubbling device introduces the air).
Aeration Tank:
A chamber used to inject air into water.
Aerobic:
Life or processes that require, or are not destroyed by, the presence of
oxygen. (See: anaerobic)
Aerobic Treatment:
Process by which microbes decompose complex organic compounds in the
presence of oxygen and use the liberated energy for reproduction and
growth. (Such processes include extended aeration, trickling filtration,
and rotating biological contactors.)
Aerosol:
1. Small droplets or particles suspended in the atmosphere, typically
containing sulfur. They are usually emitted naturally (e.g. in volcanic
eruptions) and as the result of anthropogenic (human) activities such as
burning fossil fuels. 2. The pressurized gas used to propel substances
out of a container.
Aerosol:
A finely divided material suspended in air or other gaseous environment.
Affected Landfill:
Under the Clean Air Act, landfills that meet criteria for capacity, age,
and emissions rates set by the USEPA. They are required to collect and
combust their gas emissions.
Affected Public:
1.The people who live and/or work near a hazardous waste site. 2. The
human population adversely impacted following exposure to a toxic
pollutant in food, water, air, or soil.
Afterburner:
In incinerator technology, a burner located so that the combustion gases
are made to pass through its flame in order to remove smoke and odors.
It may be attached to or be separated from the incinerator proper.
Age Tank:
A tank used to store a chemical solution of known concentration for feed
to a chemical feeder. Also called a day tank.
Agent:
Any physical, chemical, or biological entity that can be harmful to an
organism (synonymous with stressors.)
Agent Orange:
A herbicide and defoliant used in the Vietnam conflict, containing
2,4,5-trichlorophen-oxyacetic acid (2,4,5-T) and 2-4
dichlorophenoxyacetic acid (2,4-D) with trace amounts of dioxin. Public
concern over Agent Orange has centered not over the product itself, but
an unavoidable by-product that was present in only trace levels of one
of the product’s ingredients. The unavoidable trace by-product was the
dioxin compound 2,3,7,8-TCDD
Agricultural Pollution:
Farming wastes, including runoff and leaching of pesticides and
fertilizers; erosion and dust from plowing; improper disposal of animal
manure and carcasses; crop residues, and debris.
Agricultural Waste:
Poultry and livestock manure, and residual materials in liquid or solid
form generated from the production and marketing of poultry, livestock
or fur-bearing animals; also include grain, vegetable, and fruit harvest
residue.
Agroecosystem:
Land used for crops, pasture, and livestock; the adjacent uncultivated
land that supports other vegetation and wildlife; and the associated
atmosphere, the underlying soils, groundwater, and drainage networks.
AHERA Designated Person (ADP):
A person designated by a Local Education Agency to ensure that the AHERA
requirements for asbestos management and abatement are properly
implemented.
Air Binding:
Situation where air enters the filter media and harms both the
filtration and backwash processes.
Air Changes Per Hour (ACH):
The movement of a volume of air in a given period of time; if a house
has one air change per hour, it means that the air in the house will be
replaced in a one-hour period.
Air Cleaning:
Indoor-air quality-control strategy to remove various airborne
particulates and/or gases from the air. Most common methods are
particulate filtration, electrostatic precipitation, and gas sorption.
Air Contaminant:
Any particulate matter, gas, or combination thereof, other than water
vapor. (See: air pollutant.)
Air Curtain:
A method of containing oil spills. Air bubbling through a perforated
pipe causes an upward water flow that slows the spread of oil. It can
also be used to stop fish from entering polluted water.
Air Exchange Rate:
The rate at which outside air replaces indoor air in a given space.
Air Handling Unit:
Equipment that includes a fan or blower, heating and/or cooling coils,
regulator controls, condensate drain pans, and air filters.
Air Mass:
A large volume of air with certain meteorological or polluted
characteristics--e.g., a heat inversion or smog--while in one location.
The characteristics can change as the air mass moves away.
Air Monitoring:
Periodic or continuous surveillance or testing to determine the level of
compliance with statutory requirements and/or pollutant levels in air.
Air/Oil Table:
The surface between the vadose zone and ambient oil; the pressure of oil
in the porous medium is equal to atmospheric pressure.
Air Padding:
Pumping dry air into a container to assist with the withdrawal of liquid
or to force a liquefied gas such as chlorine out of the container.
Air Permeability:
Permeability of soil with respect to air. Important to the design of
soil-gas surveys. Measured in darcys or centimeters-per-second.
Air Plenum:
Any space used to convey air in a building, furnace, or structure. The
space above a suspended ceiling is often used as an air plenum.
Air Pollutant:
Any substance in air that could, in high enough concentration, harm man,
other animals, vegetation, or material. Pollutants may include almost
any natural or artificial composition of airborne matter capable of
being airborne. They may be in the form of solid particles, liquid
droplets, gases, or in combination thereof. Generally, they fall into
two main groups: (1) those emitted directly from identifiable sources
and (2) those produced in the air by interaction between two or more
primary pollutants, or by reaction with normal atmospheric constituents,
with or without photo activation. Exclusive of pollen, fog, and dust,
which are of natural origin, about 100 contaminants have been
identified. Air pollutants are often grouped in categories for ease in
classification; some of he categories are: solids, sulfur compounds,
volatile organic chemicals, particulate matter, nitrogen compounds,
oxygen compounds, halogen compounds, radioactive compound, and odors.
Air Pollution:
The presence of contaminants or pollutant substances in the air that
interfere with human health or welfare, or produce other harmful
environmental effects.
Air Pollution Control Device:
Mechanism or equipment that cleans emissions generated by a source (e.g.
an incinerator, industrial smokestack, or an automobile exhaust system)
by removing pollutants that would otherwise be released to the
atmosphere.
Air Quality Criteria:
The levels of pollution and lengths of exposure above which adverse
health and welfare effects may occur.
Air Quality Standards:
The level of pollutants prescribed by regulations that are not be
exceeded during a given time in a defined area.
Air Sparging:
Injecting air or oxygen into an aquifer to strip or flush volatile
contaminants as air bubbles up through The groundwater and is captured
by a vapor extraction system.
Air Stripping:
A treatment system that removes volatile organic compounds (VOCs) from
contaminated groundwater or surface water by forcing an airstream
through the water and causing the compounds to evaporate.
Air Toxics:
Any air pollutant for which a national ambient air quality standard (NAAQS)
does not exist (i.e. excluding ozone, carbon monoxide, PM-10, sulfur
dioxide, nitrogen oxide) that may reasonably be anticipated to cause
cancer; respiratory, cardiovascular, or developmental effects;
reproductive dysfunctions, neurological disorders, heritable gene
mutations, or other serious or irreversible chronic or acute health
effects in humans.
Airborne Particulates:
Total suspended particulate matter found in the atmosphere as solid
particles or liquid droplets. Chemical composition of particulates
varies widely, depending on location and time of year. Sources of
airborne particulates include: dust, emissions from industrial
processes, combustion products from the burning of wood and coal,
combustion products associated with motor vehicle or non-road engine
exhausts, and reactions to gases in the atmosphere.
Airborne Release:
Release of any pollutant into the air.
Alachlor:
A herbicide, marketed under the trade name Lasso, used mainly to control
weeds in corn and soybean fields.
Alar:
Trade name for daminozide, a pesticide that makes apples redder, firmer,
and less likely to drop off trees before growers are ready to pick them.
It is also used to a lesser extent on peanuts, tart cherries, concord
grapes, and other fruits.
Aldicarb:
An insecticide sold under the trade name Temik. It is 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 specifically to kill or control algae.
Aliquot:
A measured portion of a sample taken for analysis. One or more aliquots
make up a sample. (See: duplicate.)
Alkaline:
The condition of water or soil which contains a sufficient amount of
alkali substance to raise the pH above 7.0.
Alkalinity:
The capacity of bases to neutralize acids. An example is lime added to
lakes to decrease acidity.
Allergen:
A substance that causes an allergic reaction in individuals sensitive to
it.
Alluvial:
Relating to and/or sand deposited by flowing water.
Alternate Method:
Any method of sampling and analyzing for an air or water pollutant that
is not a reference or equivalent method but that has been demonstrated
in specific cases-to USEPA's satisfaction-to produce results adequate
for compliance monitoring.
Alternative Compliance:
A policy that allows facilities to choose among methods for achieving
emission-reduction or risk-reduction instead of command-and control
regulations that specify standards and how to meet them. Use of a
theoretical emissions bubble over a facility to cap the amount of
pollution emitted while allowing the company to choose where and how
(within the facility) it complies
Alternative Fuels:
Substitutes for traditional liquid, oil-derived motor vehicle fuels like
gasoline and diesel. Includes mixtures of alcohol-based fuels with
gasoline, methanol, ethanol, compressed natural gas, and others.
Ambient Air:
Any unconfined portion of the atmosphere: open air, surrounding air.
Ambient Measurement:
A measurement of the concentration of a substance or pollutant within
the immediate environs of an organism; taken to relate it to the amount
of possible exposure.
Ambient Medium:
Material surrounding or contacting an organism (e.g. outdoor air, indoor
air, water, or soil, through which chemicals or pollutants can reach the
organism. (See: biological medium, environmental medium.)
Ambient Temperature:
Temperature of the surrounding air or other medium.
Amprometric Titration:
A way of measuring concentrations of certain substances in water using
an electric current that flows during a chemical reaction.
Anaerobic:
A life or process that occurs in, or is not destroyed by, the absence of
oxygen.
Anaerobic Decomposition:
Reduction of the net energy level and change in chemical composition of
organic matter caused by microorganisms in an oxygen-free environment.
Anisotropy:
In hydrology, the conditions under which one or more hydraulic
properties of an aquifer vary from a reference point.
Annular Space, Annulus:
The space between two concentric tubes or casings, or between the casing
and the borehole wall.
Antagonism:
Interference or inhibition of the effect of one chemical by the action
of another.
Antarctic "Ozone Hole":
Refers to the seasonal depletion of ozone in the upper atmosphere above
a large area of Antarctica. (See: Ozone Hole.)
Anti-Degradation Clause:
Part of federal air quality and water quality requirements prohibiting
deterioration where pollution levels are above the legal limit.
Anti-Microbial:
An agent that kills microbes.
Applicable or Relevant and Appropriate Requirements (ARARs):
Any state or federal statute that pertains to protection of human life
and the environment in addressing specific conditions or use of a
particular cleanup technology at a Superfund site,
Applied Dose:
In exposure assessment, the amount of a substance in contact with the
primary absorption boundaries of an organism (e.g. skin, lung tissue,
gastrointestinal track) and available for absorption.
Aqueous:
Something made up of water.
Aqueous Solubility:
The maximum concentration of a chemical that will dissolve in pure water
at a reference temperature.
Aquifer:
An underground geological formation, or group of formations, containing
water. Are sources of groundwater for wells and springs.
Aquifer Test:
A test to determine hydraulic properties of an aquifer.
Aquitard:
Geological formation that may contain groundwater but is not capable of
transmitting significant quantities of it under normal hydraulic
gradients. May function as confining bed.
Architectural Coatings:
Coverings such as paint and roof tar that are used on exteriors of
buildings.
Area of Review:
In the UIC program, the area surrounding an injection well that is
reviewed during the permitting process to determine if flow between
aquifers will be induced by the injection operation.
Area Source:
Any source of air pollution that is released over a relatively small
area but which cannot be classified as a point source. Such sources may
include vehicles and other small engines, small businesses and household
activities, or biogenic sources such as a forest that releases
hydrocarbons.
Aromatics:
A type of hydrocarbon, such as benzene or toluene, with a specific type
of ring structure. Aromatics are sometimes added to gasoline in order to
increase octane. Some aromatics are toxic.
Arsenicals:
Pesticides containing arsenic.
Artesian (Aquifer or Well):
Water held under pressure in porous rock or soil confined by impermeable
geological formations.
Asbestos:
A mineral fiber that can pollute air or water and cause cancer or
asbestosis when inhaled. USEPA has banned or severely restricted its use
in manufacturing and construction.
Asbestos Abatement:
Procedures to control fiber release from asbestos-containing materials
in a building or to remove them entirely, including removal,
encapsulation, repair, enclosure, encasement, and operations and
maintenance programs.
Asbestos Assessment:
In the asbestos-in-schools program, the evaluation of the physical
condition and potential for damage of all friable asbestos containing
materials and thermal insulation systems.
Asbestos Program Manager:
A building owner or designated representative who supervises all aspects
of the facility asbestos management and control program.
Asbestos-Containing Building Materials (ACBM):
Asbestos-containing materials found in or on interior structural members
or other parts of a building.
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 disease
makes breathing progressively more difficult and can be fatal.
Ash:
The mineral content of a product remaining after complete combustion.
Assay:
A test for a specific chemical, microbe, or effect.
Assessment Endpoint:
In ecological risk assessment, an explicit expression of the
environmental value to be protected; includes both an ecological entity
and specific attributed thereof. entity (e.g. salmon are a valued
ecological entity; reproduction and population maintenance--the
attribute--form an assessment endpoint.)
Assimilation:
The ability of a body of water to purify itself of pollutants.
Assimilative Capacity:
The capacity of a natural body of water to receive wastewaters or toxic
materials without deleterious effects and without damage to aquatic life
or humans who consume the water.
Attenuation:
The process by which a compound is reduced in concentration over time,
through absorption, adsorption, degradation, dilution, and/or
transformation. an also be the decrease with distance of sight caused by
attenuation of light by particulate pollution.
Attrition:
Wearing or grinding down of a substance by friction. Dust from such
processes contributes to air pollution.
Availability Session:
Informal meeting at a public location where interested citizens can talk
with USEPA and state officials on a one-to-one basis.
Available Chlorine:
A measure of the amount of chlorine available in chlorinated lime,
hypochlorite compounds, and other materials used as a source of chlorine
when compared with that of liquid or gaseous chlorines.
Avoided Cost:
The cost a utility would incur to generate the next increment of
electric capacity using its own resources; many landfill gas projects'
buy back rates are based on avoided costs.
A-Scale Sound Level:
A measurement of sound approximating the sensitivity of the human ear,
used to note the intensity or annoyance level of sounds.
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