Environmental Dictionary L-N - Environmental Links - 1/1/2015 - Health Asbestos Asbestosis Mesothelioma Lung Cancer

Environmental Dictionary L-N

LA-50

Coagulant-Cationic Flocculant - Clarification/Settling (ETUS).

label

any written, printed or graphic sign or symbol displayed on or affixed to containers of hazardous chemicals. A label should identify the hazardous material, appropriate hazard warnings, and name and address of the chemical manufacturer, importer, other responsible party.

laboratory

Per 29 CFR 1910. A facility where the "laboratory use of hazardous chemicals" occurs, where relatively small quantities of hazardous chemicals are used on a non-production basis.

laboratory scale (activity)

the work involves containers of substances used for reactions and transfers that are designed for easy and safe handling by one person. Workplaces that produce commercial quantities of materials are excluded from the definition of "Laboratory."

laboratory type hood

lab device enclosed on five sides with a movable sash or fixed access port on the sixth side. In operation it draws and then exhausts air from the lab to prevent or minimize the escape of air contaminants. It enables materials to be manipulated with the hood by the employees hands and arms only.Walk-in hoods are permitted it airflow and exhaust remove contaminants and the employee is not within the enclosure when contaminants are released.

laboratory use

of hazardous chemicals is when all of the following conditions are met: a) Chemical manipulations are carried out on a "laboratory scale." b) Multiple chemical procedures or chemicals are used. c) The procedures are neither part of nor simulate a production process. d) Protective lab practices and equipment are available and in common use to minimize the potential for employee exposure to hazardous chemicals.

lacrimation

secretion and discharge of tears.

lacrimator

a material that produces tears.

LAER

Lowest Achievable Emission Rate.

lagoon

(1) a shallow pond where sunlight, bacterial action, and oxygen work to purify wastewater; also used to storage of wastewaters or spent nuclear fuel rods. (2) shallow body of water, often separated from the sea by coral reefs or sandbars.

LAI

Laboratory Audit Inspection.

LAMP-OIL

Liquid Wax (ETUS).

land application

discharge of wastewater onto the ground for treatment or reuse. (See: irrigation).

land bans

prohibitions of specific toxic materials from disposal in landfills under RCRA.

land farming

a disposal process in which hazardous waste deposited on or in the soil is naturally degraded by microbes.

landfills

(1) sanitary landfills are land disposal sites for non-hazardous solid wastes at which the waste is spread in layers, compacted to the smallest practical volume, and cover material applied at the end of each operating day.(2) secure chemical landfills are disposal sites for hazardous waste. They are selected and designed to minimize the chance of release of hazardous substances into the environment.

langelier index

a means of expressing the degree of saturation of a water as related to calcium carbonate solubility.

LAP

Laboratory Analytical Protocol.

latency period

the time that elapses between exposure and the first manifestations of disease or illness. Latency periods can range from minutes to decades, depending on the hazardous material.

lateral sewers

pipes running underneath city streets that collect sewage.

lavage

a washing of a hollow organ, such as the stomach, using a tube and fluids.

lay language

Language that can be understood by the public without any special training.

layered or stratified bed

resins with sufficient difference in density and hydraulic characteristics to be layered in the same tank in place of two separate tanks.

LC

Lethal Concentration.

LC

Liquid Chromatography.

LC50/lethal concentration

median lethal concentration, a standard measure of toxicity. It tells how much of a substance is needed to kill half of a group of experimental organisms at a specific time of observation. (See LD50).

LCD

Local Climatological Data.

LCLo

Lethal concentration low. The lowest concentration of a substance in air reported to have caused death in humans or animals. The reported concentrations may be entered for periods of exposure that are less than 24 hours (acute) or greater than 24 hours (subacute and chronic).

LCM

Life Cycle Management.

L-COOL

Cooling Water Treatment - Multifunctional (ETUS).

LCRS

Leachate Collection and Removal System.

LD

Land Disposal.

LD

Lethal Dose.

LDCRS

Leachate Detection, Collection, and Removal System.

LDEQ

Louisiana Department of Environmental Quality.

LDF

Land Disposal Facility.

LDIP

Laboratory Data Integrity Program.

LD 0

the highest concentration of a toxic substance at which none of the test organisms die.

LD 50/lethal dose

the dose of a toxicant that will kill 50 percent of the test organisms within a designated period of time. The lower the LD 50, the more toxic the compound.

LD L0

the lowest concentration and dosage of a toxic substance which kills test organisms.

LDR

Land Disposal Restriction.

LDS

Leak Detection System.

LEA

local education agency; local school administrations held responsible for meeting AHERA requirements.

LEA

Local Enforcement Agency.

leachate

materials that pollute water as it seeps through solid waste.

leachate collection system

a system that gathers leachate and pumps it to the surface for treatment.

leaching

the process by which nutrient chemicals or contaminants are dissolved and carried away by water, or are moved into a lower layer of soil.

lead

a heavy metal that is hazardous to health if breathed or swallowed. Its use in gasoline, paints, and plumbing compounds has been sharply restricted or eliminated by federal laws and regulations. (See: heavy metals).

lead agency

means the agency that provides the OSC/RPM to plan and implement response action under the NCP. EPA, the USCG, another federal agency, or a state (or political subdivision of a state) operating pursuant to a contract or cooperative agreement executed pursuant to section 104(d)(1) of CERCLA, or designated pursuant to a Superfund Memorandum of Agreement (SMOA) entered into pursuant to subpart F of the NCP or other agreements may be the lead agency for a response action.In the case of a release of a hazardous substance, pollutant, or contaminant, where the release is on, or the sole source of the release is from, any facility or vessel under the jurisdiction, custody, or control of Department of Defense (DOD) or Department of Energy (DOE), then DOD or DOE will be the lead agency. Where the release is on, or the sole source of the release is from, any facility or vessel under the jurisdiction, custody, or control of a federal agency other than EPA, the USCG, DOD, or DOE, then that agency will be the lead agency for remedial actions and removal actions other than emergencies. The federal agency maintains its lead agency responsibilities whether the remedy is selected by the federal agency for non-NPL sites or by EPA and the federal agency or by EPA alone under CERCLA section 120. The lead agency will consult with the support agency, if one exists, throughout the response process.

leaded gasoline

gasoline to which lead has been added to raise the octane level.

leakage

the presence in the effluent of a species of ions in the feed to an ion exchanger.

Legionella

means a genus of bacteria, some species of which have caused a type of pneumonia called Legionnaires Disease.

LEL or LFL

Lower explosive limit, or lower flammable limit, of a vapor or gas; the lowest concentration (lowest percentage of the substance in air) that will produce a flash of fire when an ignition source (heat, arc, or flame) is present. At concentrations lower than the LEL, the mixture is too "lean" to burn. Also see "UEL".

LEL

Lowest Effect Level. It is the lowest dose used in a test which produced toxic effects.

LEP

Laboratory Evaluation Program.

LEPC

Local Emergency Planning Committee; groups defined in SARA as responsible for developing emergency plans.

lesion

an abnormal change, injury, or damage to tissue or to an organ.

lethargy

sluggish feeling.

leukemia

a progressive, malignant disease of the blood-forming organs.

level of concentration

the concentration in air of an extremely hazardous substance above which there may be serious immediate health effects to anyone exposed to it for short periods of time.

L-FEED

Boiler Feed Water Treatment - Multifunction (ETUS).

LFL

see Lower Explosive Limit, Lower Flammable Limit.

LFM or lfm

Linear feet per minute.

LHW

Liquid Hazardous Waste.

LIDAR

Light Detection and Ranging.

life cycle

the stages an organism passes through during its existence.

lift

in a sanitary landfill, a compacted layer of solid waste and the top layer of cover material.

lifting station

(see: pumping station).

lignin

the major noncellulose constituent of wood.

LIMB

Limestone-Injection, Multi-State Burner.

lime

a common water treatment chemical. Limestone, CaCO3, is burned to produce quicklime, CaO, which is mixed with water to produce slaked, or hydrated, lime.

limestone scrubbing

process in which sulfur gases moving towards a smokestack are passed through a limestone and water solution to remove sulfur before it reaches the atmosphere.

limited emergency condition

refers to "an incident involving a greater hazard or larger area which poses a potential threat to life or property, and which may require a limited evacuation of the surrounding area."

limiting factor

a condition, whose absence, or excessive concentration, is incompatible with the needs or tolerance of a species or population and which may have a negative influence on their ability to grow or even survive.

limits of flammability

see Flammable Limits.

limnology

the study of the physical, chemical, meteorological, and biological aspects of fresh water.

liner

(1) a relatively impermeable barrier designed to prevent leachate from leaking from a landfill. Liner materials include plastic and dense clay. (2) an insert or sleeve for sewer pipes to prevent leakage or infiltration.

Lipid Granuloma

a mass of chronically inflamed tissue that is usually infective.

lipid pneumonia

a chronic condition caused by aspiration of oily substances into the lungs.

lipid solubility

the maximum concentration of a chemical that will dissolve in fatty substances; lipid soluble substances are insoluble in water. If a substance is lipid soluble it will very selectively disperse through the environment via living tissue.

lipophilic

having an affinity for oil. The opposite of hydrophilic (i.e., hydrophobic).

liquefaction

changing a solid into a liquid form.

liquid trap

means sumps, well cellars, and other traps used in association with oil and gas production, gathering, and extraction operations (including gas production plants), for the purpose of collecting oil, water, and other liquids. These liquid traps may temporarily collect liquids for subsequent disposition or reinjection into a production or pipeline stream, or may collect and separate liquids from a gas stream.

liquefied compressed gas

DOT describes as a gas which, under the charged pressure, is partially liquid at a temperature of 70¿F.

list

shorthand term for EPA list of violating facilities or lists of firms debarred from obtaining government contracts because they violated certain sections of the Clean Air Act or Clean Water Acts. The list is maintained by the Office of Enforcement and Compliance Monitoring.

listed waste

wastes listed as hazardous under RCRA but which have not been subjected to the Toxic Characteristics Listing Process because the dangers they present are considered self-evident.

LLRW

Low Level Radioactive Wastes.

LLRWPA

Low-Level Radioactive Waste Policy Act.

LMFBR

Liquid Metal Fast Breeder Reactor.

LNG

Liquefied Natural Gas.

LOAFL

Lowest Observed Adverse Effect Level.

local emergency planning committee

a committee appointed by the state emergency response commission, as required by SARA Title III to formulate a comprehensive emergency plan for its jurisdiction.

local resources

refers to all the resources that have been identified in the organizations emergency response plan as being under the organizations direct control and those resources controlled by other entities within the geographical boundaries of the jurisdiction.

local ventilation

the drawing off and replacement of contaminated air directly from its source. This type of ventilation is recommended for hazardous airborne materials.

LOIS

Loss of Interim Status.

LOL

Laughing Out Loud.

low level radioactive waste (LLRW)

wastes less hazardous than most of those generated by a nuclear reactor. Usually generated by hospitals, research laboratories, and certain industries. The Department of Energy, Nuclear Regulatory Commission, and EPA share responsibilities for managing them (See: high-level radioactive wastes).

lower explosive limit (LEL)

the concentration of a compound in air below which a flame will not propagate if the mixture is ignited.

lowest achievable emission rate

under the Clean Air Act, this is the rate of emissions which reflects (a) the most stringent emission limitation which is contained in the implementation plan of any state for such source unless the owner or operator of the proposed source demonstrates such limitations are not achievable; or (b) the most stringent emissions limitation achieved in practice, which ever is more stringent.Application of this term does not permit a proposed new or modified source to emit pollutants in excess of existing new source standards.

lowest-observed-adverse-effect level

(LOAEL) in dose-response experiments, the experimental exposure level representing the lowest level tested at which adverse effects were demonstrated.

LP

Legislative Proposal.

LPG

Liquefied Petroleum Gas.

LRMS

Low Resolution Mass Spectroscopy.

LSI

Legal Support Inspection.

LSSEQUE

Irrigation Water Treatment (ETUS).

LTD

Land Treatment Demonstration.

LTU

Land Treatment Unit.

LUFT

Leaking Underground Fuel Tank.

LUST

Leaking Underground Storage Tank.

LUST

leaking UST.

LWCF

Land and Water Conservation Fund.

MAB

Man and Biosphere Program.

macro-floc

the stage of flocculation when large, rapidly settling particles are present.

macroporous

having large pores.

MACT

maximum achievable control technology; controls and procedures required under the CAA Amendments for certain air pollutant sources.

MADCAP

Model of Advection, Diffusion and Chemistry for Air Pollution.

MAER

Maximum Allowable Emission Rate.

maintenance

means the normal operational upkeep to prevent an underground storage tank system from releasing product.

MAJCOM

Major Commands.

major modification

this term is used to define modifications with respect to Prevention of Significant Deterioration and New Source Review under the Clean Air Act and refers to modification to major stationary sources of emissions and provides significant pollution increase levels below which a modification is not considered major.

major stationary sources

term used to determine to applicability of Prevention of Significant Deterioration and new source regulations. In a nonattainment area, any stationary pollutant source that has a potential to emit more than 100 tons per year is considered a major stationary source. In PSD area the cutoff level may be either 100 or 250 tons, depending upon the type of source.

malaise

a feeling of general discomfort, distress, or uneasiness; an out-of-sorts feeling.

management of migration

means actions that are taken to minimize and mitigate the migration of hazardous substances or pollutants or contaminants and the effects of such migration. Measures may include, but are not limited to, management of a plume of contamination, restoration of a drinking water aquifer, or surface water restoration.

manganese greensand

greensand which has been processed to incorporate in its pores and on its surface the higher oxides of manganese.

manufacturers formulation

a list of substances or component parts as described by the maker of a coating, pesticide.

MAP3S

Multistate Atmospheric Power Production Pollution Study.

MARC

Mining and Reclamation Council.

marine sanitation device

any equipment installed on board a vessel to receive, retain, treat, or discharge sewage and any process to treat such sewage.

marsh

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

martial law

refers to the temporary emergency powers which can be given to law enforcement personnel, to protect the lives and property of citizens.

masking

blocking out one sight, sound, or smell with another.

matabolite

any substance produced in or by biological processes and derived from a pesticide.

MATC

Maximum Allowable Toxicant Concentration.

material

All types of classifications of chemicals such as products, raw materials, isolated manufacturing intermediates, as well as hazardous and non-hazardous chemicals. Also covered "materials" are items that may normally be considered non-hazardous, but may give off hazardous chemicals during customary and reasonably foreseeable use and misuse, handling and storage; such items are not subject to the article exemption under the OSHA HCS (29 CFR 1910.1200).

material safety data sheet (MSDS)

a compilation of information required under the OSHA Communication Standard on the identity of hazardous chemicals, health, and physical hazards, exposure limits, and precautions. Section 311 of SARA requires facilities to submit MSDSs under certain circumstances.

maximum contaminant level

the maximum permissible level of a contaminant in water delivered to any user of a public water system. MCLs are enforceable standards.

maximum contaminant level goal (MCLG)

this is a number that is associated with no adverse health effects from drinking water containing a particular contaminant over a lifetime. For chemicals believed to cause cancer, for example, the MCLGs are set at zero, as there is no known safe consumption level. It is a non-enforceable, ideal health goal issued as part of the NPDWRs. MCLs are set as close to MCLGs as possible, considering costs and technology.

MBAS

Methylene Blue Active Substance - anionic substances which react with cationically charged methylene blue. The MBAS method is commonly used to detect and quantify anionic surfactants in aqueous systems.

MBDA

Minority Business Development Agency.

MBER

Minority Business Enterprise Representative.

MCA

Manufacturing Chemists Association.

MCC-IP

Materials Characterization Center Static Leach Test.

MCL

Maximum Contaminant Level.

MCLG

Maximum Contaminant Level Goal.

MCP

Municipal Compliance Plan.

MDA

Methylenedianilline.

MDEQ

Massachusetts Department of Environmental Quality.

mechanical aeration

use of mechanical energy to inject air into water to cause a waste stream to absorb oxygen.

mechanical agitation

agitation of a liquid medium through the use of mechanical equipment such as impellers or paddles.

mechanical turbulence

the erratic movement of air caused by local obstructions such as buildings.

media

specific environments-air, water, soil-which are the subject of regulatory concern and activities.

Media Center

refers to a facility staffed by spokespersons from multiple response organizations for the purpose of providing a single designated point of contact with the media and to facilitate exchange of information among spokespersons from different organizations.This type of facility is also referred to as a Joint Public Information Center (JPIC), a Joint Information Center (JIC), or an Emergency News Center (ENC).

MEFR

Maximum Expiratory Flow Rate.

MEI

Maximum Exposed Individual.

melting point

The melting point or freezing point of a pure substance is the temperature at which its crystals are in equilibrium with the liquid phase at atmospheric pressure. The term "melting point" is used when the equilibrium temperature is approached by heating the solid. The terms melting point and freezing point are often used interchangeably, depending on whether the substance Is being heated or cooled.

MEM

Modal Emission Model.

membrane

a barrier, usually thin, that permits the passage only of particles up to a certain size or of special nature.

MEP

Maximum Extent Practicable.

MEP

Multiple Extraction Procedure.

mercury

a heavy metal, highly toxic if breathed or swallowed. It can accumulate in the environment.

MERL

Municipal Environmental Research Laboratory.

MESS

Model Evaluation Support System.

metabolism

the chemical and physical processes whereby the body functions.

metabolize

to convert food, such as soluble organic matter, to cellular matter and gaseous by-products by a biological process.

metal ion

an atom or radical that has lost or gained one or more electrons and has thus acquired an electric charge.Positively charged ions are cations, and those having a negative charge are anions. An ion often has entirely different properties from the element (atom) from which it was formed.

metastasis

the transmission of a disease from one part of the body to another.

meter (m)

a measure of length; 100 cm; the equivalent of 39,371 in.

methane

a colorless, nonpoisonous, flammable gas emitted by marshes and dumps undergoing anaerobic decomposition.

methemoglobinemia

the presence of methemoglobin in the bloodstream caused by the reaction of materials with the hemoglobin in red blood cells that reduces their oxygen-carrying capacity. Methemoglobin is a soluble, brown, crystalline blood pigment that differs from hemoglobin in that it contains ferric iron and is unable to combine reversibly with molecular oxygen.

Method 18

an EPA test method which uses gas chromatographic techniques to measure the concentration of individual volatile organic compounds in a gas stream.

Method 24

an EPA reference method to determine density, water content and total volatile content (water and VOC) of coatings.

Method 25

an EPA reference method to determine the VOC concentration in gas stream.

MFBI

Major Fuel Burning Installation.

MFC

Metal Finishing Category.

mg

milligram (1/1000, 10-3, of a gram).

mg/kg

milligrams per kilogram. Dosage used in toxicology testing to indicate a dose administered per kg of body weight (50 mg = 1 teaspoonful).

mg/m3

milligrams per cubic meter of air. mg/m3 = ppm X MW + 24.45.

mgd

millions of gallons per day. Mgd is a measurement of water flow.

mg/l

Milligrams per Liter.

MH

Man-Hours.

MHD

Magnetohydrodynamics.

MIC

Methyl Isocyanate.

MICE

Management Information Capability for Enforcement.

microbes

Microscopic organisms such as algae, animals, viruses, bacteria, fungus, and protozoa, some of which cause diseases.(See: microorganism).

microbial pesticide

a microorganism that is used to control a pest. They are of low toxicity to man.

micro-floc

the stage of flocculation when small visible particles have started to form.

microgram

one one-millionth of a gram.

micrometer

one one-millionth of a meter; occasionally referred to as a micron.

MICROMORT

A One-in-a-Million Change of Death from and Environmental Hazard.

micron

a linear measure equal to one millionth of a meter, or .00003937 inch. The symbol for the micron is the Greek letter "u".

microorganism

organisms (microbes) observable only through a microscope; larger, visible types are called macroorganisms.

milligrams per liter

this is a weight per volume measurement used in water and wastewater analysis. It is interchangeable with "parts per million" (ppm).

Millimeter (mm)

1/1,000 of a meter.

million-gallons per day (MGD)

a measure of water flow.

mineral

any inorganic or fossilized organic material having a definite chemical composition and structure found in a natural state.

Mine Safety and Health Administration

see MSHA.

MIPR

Military Interagency Procurement Request.

MIS

Management Information System.

miscellaneous oil spill control agent

is any product, other than a dispersant, sinking agent, surface collecting agent, biological additive, or burning agent, that can be used to enhance oil spill cleanup, removal, treatment, or mitigation.

miscible

describes liquids that can be mixed in any ratio.

miscibility

the ability of two liquids, not mutually soluble, to mix.

mist

liquid particles measuring 500 to 40 microns, that are found by condensation of vapor. By comparison, fog particles are smaller than 40 microns.

MITI

Japanese Ministry International Trade & Industry.

mitigation

measures taken to reduce adverse impacts on the environment.

mixed liquor

activated sludge and water containing organic matter being treated in an aeration tank.

mixture

a heterogeneous association of materials that cannot be represented by a chemical formula and that does not undergo chemical change as a result of interaction amongst the mixed materials. The constituent materials may or may not be uniformly dispersed and can usually be separated by mechanical means (as opposed to a chemical reaction). Uniform liquid mixtures are called solutions. "If a hazardous chemical is present in the mixture in reportable quantities (i.e., 0.1% for carcinogens and 1.0% for other health hazards), it must be reported unless the mixture has been tested as a whole" (OSHA CPL 23-02.38A).

ML

Meteorology Laboratory.

ml

Milliliter. A metric unit of capacity equal to 1 cubic centimeter or about 1/16 in3.

MLD

mild irritation effects.

mm Hg

a measure of pressure in millimeters of a mercury column above a reservoir. See atm.

MMI

mucous membrane effects.

MMS

Minerals Management Service.

MOA

Memorandum of Agreement.

mobile source

a moving producer of air pollution, mainly forms of transportation -- cars, motorcycles, planes.

MOD

moderate irritation effects.

model plant

a description of a typical but theoretical plant used for developing economic, environmental impact analyses as support for regulations or regulatory guidelines. It is an imaginary plant, with features of existing or future plants used to estimate the cost of incorporating air pollution control technology as the first step in exploring the economic impact of a potential NSPS.

modeling

an investigative technique using a mathematical or physical representation of a system or theory that accounts for all or some its known properties. Models are often used to test the effect of changes of system components on the overall performance of the system.

MOI

Memorandum of Intent.

moisture content

the water loss of a fully hydrated resin under controlled drying conditions.

mole

a unit weight or volume of a chemical corresponding to its molecular weight. A mole of water weighs 18 g, and its vapor occupies 22.4 L at standard temperature and pressure.

molecular formula

A written representation, using symbols, of a chemical entity. It shows the actual number and kind of atoms in a molecule.

molecular weight

the mass in grams per mole of a substance.See mole.

molecule

the smallest particle of an element or compound retaining its characteristics.

monitoring

periodic or continuous sampling to determine the level of pollution or radioactivity.

monitoring wells

wells drilled at a hazardous waste management facility or Superfund site to collect ground-water samples for the purpose of physical, chemical, or biological analysis to determine the amounts, types, and distribution of contaminants in the ground water beneath the site.

monoclonal antibodies

(Also called MABs and MCAs) molecules of living organisms that selectively find and attach to other molecules to which their structure conforms exactly. This could also apply to equivalent activity by chemical molecules.

monomer

a molecule, usually an organic compound, having the ability to join with a number of identical molecules to form a polymer.

MOS

Margin of Safety.

motor fuel

means petroleum or a petroleum-based substance that is motor gasoline, aviation gasoline, No.1 or No. 2 diesel fuel, or any grade of gasohol, and is typically used in the operation of a motor engine.

MOU

Memoranda of Understanding

MPP

Merit Promotion Plan.

MPPCF

millions of particles per cubic foot of air, based on impinger samples counted by light-field techniques (OSHA).

MPRSA

Marine Protection, Research and Sanctuaries Act.

MPTDS

MPTER Model with Deposition and Settling of Pollutants.

MPTER

Multiple Point Source Model with Terrain.

MRA

Minimum Retirement Age.

MREM

Milliroentgen Equivalent in Man.

MS

Mass Spectrometry.

MSAM

Multi-Keyed Indexed Sequential File Access Method.

MSDS

Material safety data sheet. OSHA has established guidelines for the descriptive data that should be concisely provided on a data sheet to serve as the basis for written hazard-communication programs. The thrust of the law is to have those who make, distribute, and use hazardous materials be responsible for effective communication. See the Hazard Communication Rule, 29 CFR, Pat 1910, 1200, as amended, Section g. See Schedule I, Section 12, of the Canadian Hazardous Products Act.

MSHA

Mine Safety and Health Administration. A Federal agency within the US Department of Labor that devises and promulgates mandatory safety and health rules for mines.

MSK

Muscular-skeletal effects.

MSL

Mean Sea Level.

MSW

Municipal Solid Waste.

MSWL

municipal solid waste landfill.

MSWLF

Municipal Solid Waste Landfill Facility.

MTB

Materials Transportation Bureau.

MTBE

Methyl Tertiary Butyl Ether.

MTD

Maximum Tolerated Dose.

MTDDIS

Mesoscale Transport Diffusion and Deposition Model for Industrial Sources.

MTG

Media Task Group.

MTS

Management Tracking System.

MTSL

Monitoring and Technical Support Laboratory.

MTU

Mobile Treatment Unit.

muck soils

earth made from decaying plant materials.

mucous membrane

the mucous-secreting membrane lining the hollow organs of the body; i.e., nose, mouth, stomach, intestine, bronchial tubes, and urinary tract.

mulch

a layer of material (wood chips, straw, leaves) placed around plants to hold moisture, prevent weed growth, and enrich soil.

multiple use

harmonious use of land for more than one purpose; i.e., grazing of livestock, wildlife production, recreation, watershed and timer production. Not necessarily the combination of uses that will yield the highest economic return or greatest unit output.

MUT, Mutagen

a material that induces genetic changes (mutations) in the DNA of chromosomes. Chromosomes are the "blueprints" of life within individual cells.

mutagen

any substance that causes changes in the genetic structure in subsequent generations.

mutate

to bring about a change in the genetic constitution of a cell by altering its DNA. In turn, "mutagenesis" is any process by which cells are mutated.

mutual aid agreement

refers to an agreement between two or more jurisdictions or between a jurisdiction and one or more private entities in which the signatories promise to come to provide assistance to each other when such assistance is requested.

MVA

Multivariate Analysis.

MVAPCA

Motor Vehicle Air Pollution Control Act.

MVEL

Motor Vehicle Emissions Laboratory.

MV/M

Motor Vehicle Inspection/Maintenance.

MVL

Maximum Use Limits.

MVRS

Marine Vapor Recovery System.

MVV

Maximal Voluntary Ventilation.

MW

see Molecular Weight.

MW

Megawatt.

MWC

Municipal Waste Combustor.

MWL

Municipal Waste Leachate.

MWTA

Medical Waste Treatment Act.

NA

Nonattainment.

NA, ND

Not applicable, not available; not determined.

NAA

Nonattainment Areas.

NA Number

see DOT Identification Numbers.

NAAQS

National Ambient Air Quality Standards; standards under CAA that require states to develop SIPs and establish maximum air pollutant emissions standards.

NAAS

National Air Audit System.

NAC

National Asbestos Council.

NACA

National Agricultural Chemicals Association.

NADB

National Atmospheric Data Bank.

NADP

National Atmospheric Deposition Program.

NAE

National Academy of Engineering.

NAEP

National Association of Environmental Professionals.

NAIS

Neutral Administrative Inspection System.

NALD

Nonattainment Areas Lacking Demonstrations.

NAM

National Association of Manufacturers.

NAMA

National Air Monitoring Audits.

NAMF

National Association of Metal Finishers.

NAMS

National Air Monitoring System.

NANCO

National Association of Noise Control Officials.

NAPAP

National Acid Precipitation Assessment Program.

NAPBN

National Air Pollution Background Network.

NAPBTAC

National Air Pollution Control Technical Advisory Committee.

NAR

National Asbestos Registry.

NARA

National Air Resources Act.

NARA

National Archives and Records Administration.

narcosis

stupor or unconsciousness often produced by exposure to organic chemicals.

narcotic

An material that produces stupor, insensibility and sometimes unconsciousness.

narrative summary

refers to an objective description of the actions observed by the evaluator during the exercise. Identifies issues raised during the course of the exercise activities and includes recommendations for improvement.

NARS

National Asbestos-Contractor Registry System.

NAS

National Academy of Sciences.

NASA

National Aeronautics and Space Administration.

NATICH

National Air Toxics Information Clearinghouse.

National Ambient Air Quality Standards (NAAQS)

air quality standards established by EPA that apply to outside air.

National Emissions Standards For Hazardous Air Pollutants

also known as NESHAPS, these emissions standards set by EPA for an air pollutant not covered by NAAQS that may cause an increase in deaths or in serious, irreversible, or incapacitating illness.Primary standards are designed to protect human health, secondary standards to protect public welfare.

National Fire Protection Association

see NFPA.

National Oil and Hazardous Substances Contingency Plan

the federal regulation that guides determination of the sites to be corrected under the Superfund program and the program to prevent or control spills into surface waters or other portions of the environment. (Also known as NOHSCP/NCP).

National Pollutant Discharge Elimination System (NPDES)

a provision of the Clean Water Act which prohibits discharge of pollutants into waters of the United States unless a special permit is issued by EPA, a state, or (where delegated) a tribal government on an Indian reservation.

National Primary Drinking Water Regulations (NPDWRs)

developed by the U.S. EPA, these regulations were designed to keep drinking water clean and to protect the public from waterborne disease. These regulations define either a Maximum Contaminant Level or a treatment technique requirement to control the presence of contaminants in drinking water.

National Priorities List (NPL)

EPA's list of the most serious uncontrolled or abandoned hazardous waste sites identified for possible long-term remedial action under Superfund. A site must be on the NPL to receive money from the Trust Fund for remedial action. The list is based primarily on the score a site receives from the Hazard Ranking System. EPA is required to update the NPL at least once a year.

National Response Center

the federal operations center that receives notification of all releases of oil and hazardous substances into the environment. The Center, open 24 hours a day, is operated by the U.S. Coast Guard, which evaluates all reports and notifies the appropriate agency.

National Response Team (NRT)

representatives of 13 federal agencies that, as a team, coordinate federal responses to nationally significant incidents of pollution and provide advice and technical assistance to the responding agency(ies) before and during a response action.

National Toxicology Program

see NTP.

natural gas

a natural fuel containing methane and hydrocarbons that occurs in certain geologic formations.

natural resources

means land, fish, wildlife, biota, air, water, ground water, drinking water supplies, and other such resources belonging to, managed by, held in trust by, appertaining to, or otherwise controlled by the United States (including the resources of the exclusive economic zone defined by the Magnuson Fishery Conservation and Management Act of 1976), any state or local government, any foreign government, any Indian tribe, or, if such resources are subject to a trust restriction on alienation, any member of an Indian tribe.

natural selection

the process of survival of the fittest, by which organisms that adapt to their environment survive and those that don't disappear.

naturally occurring background levels

ambient concentrations of chemicals that are present in the environment and have not been influenced by humans (e.g., aluminum, manganese).

nausea

a tendency to vomit; a feeling of sickness in the stomach.

navigable waters

traditionally, waters sufficiently deep and wide for navigation by all, or specified sizes of vessels; such waters in the United States come under federal jurisdiction and are included in certain provisions of the Clean Water Act.

navigable waters

as defined by 40 CFR 110.1, means the waters of the United States, including the territorial seas. The term includes: (a) All waters that are currently used, were used in the past, or may be susceptible to use in interstate or foreign commerce, including all waters that are subject to the ebb and flow of the tide; (b) Interstate waters, including interstate wetlands; (c) All other waters such as intrastate lakes, rivers, streams (including intermittent streams), mudflats, sandflats, and wetlands, the use, degradation, or destruction of which would affect or could affect interstate or foreign commerce including any such waters:(1) That are or could be used by interstate or foreign travelers for recreational or other purposes;(2) From which fish or shellfish are or could be taken and sold in interstate or foreign commerce;(3) That are used or could be used for industrial purposes by industries in interstate commerce; (d) All impoundments of waters otherwise defined as navigable waters under this section; (e) Tributaries of waters identified in paragraphs (a) through (d) of this definition, including adjacent wetlands; and (f) Wetlands adjacent to waters identified in paragraphs (a) through (e) of this definition: Provided, that waste treatment systems (other than cooling ponds meeting the criteria of this paragraph) are not waters of the United States.

NAWC

National Association of Water Companies.

NAWDEX

National Water Data Exchange.

NBAR

Nonbinding Preliminary Allocation of Responsibility.

NBS

National Bureau of Standards.

NCA

National Coal Association.

NCA

Noise Control Act.

NCAC

National Clean Air Coalition.

NCAF

National Clean Air Fund.

NCAMP

National Coalition Against the Misuse of Pesticides.

NCAQ

National Commission on Air Quality.

NCAR

National Center for Atmospheric Research.

NCBC

Naval Coalition Battalion Center.

NCHS

National Center for Health Statistics.

NCI

National Cancer Institute. A part of the National Institutes of Health that studies cancer.

NCM

National Coal Model.

NCM

Notice of Commencement of Manufacture.

NCO

Negotiated Consent Order.

NCP

National Contingency Plan (1990); federal regulation promulgated to implement CERCLA and CWA sec. 311.

NCP

Noncompliance Penalties.

NCP

Nonconformance Penalty.

NCR

Noncompliance Report.

NCR

Nonconformance Report.

NCRIC

National Chemical Response and Information Center.

NCS

National Compliance Strategy.

NCWQ

National Commission On Water Quality.

NDD

Negotiation Decision Document.

NDDB

Natural Diversity Database.

NDIR

Nondispersive Infrared Analysis.

NDS

National Dioxin Study.

NDS

National Disposal Site.

NDSL

Non-Domestic Substances List (Environment Canada).

NDWAC

National Drinking Water Advisory Council.

NEA

National Energy Act.

NEC

National Electric Code.

necrosis

death of cells that can discolor areas on a plant or kill the entire plant.

NEDA

National Environmental Development Association.

NEDS

National Emissions Data Systems.

NEMA

National Electrical Manufacturers Association.

NEO

Neoplastic effects; production of tumors.

neoplasia

A condition characterized by the presence of now growths (tumors). EXAMPLE LAY LANGUAGE: (benign or malignant) tumor.

neoplasm

a new or abnormal tissue growth that is uncontrollable and progressive.

nephrotoxin

A material that may cause effects and potential injury to the kidneys. EXAMPLE LAY LANGUAGE: material that may cause kidney damage, kidney toxin, causes kidney damage.

nematocide

a chemical agent which is destructive to nematodes (round worms or threadworms).

NEP

National Estuary Program.

NEPA

National Environmental Policy Act.

NER

National Emissions Report.

NEROS

Northeast Regional Oxidant Study.

NESCAUM

Northeast States for Coordinated Air Use Management.

NESHAP

National Emission Standards for Hazardous Air Pollutants; federal emissions standards for HAPs regulated under CAA.

NETC

National Emergency Training Center.

NETTING

Emission Trading Used to Avoid PSD/NSR Permit Review Requirements.

neural

Describing a nerve or the nervous system.

neuritis

inflammation of the nerves.

neurotoxin

A material that affects the nerve cells and may produce emotional or behavioral abnormalities. EXAMPLE LAY LANGUAGE: cause effects on nervous system.

neutral

in pH terms, 7; neither acid nor basic.

neutralize

to render chemically harmless; to return the pH to the neutral level of 7 by adding acid (base) to a basic (acidic) compound.

neutralization

most commonly, a chemical reaction that produces a resulting environment that is neither acidic nor alkaline.Also, the addition of a scavenger chemical to an aqueous system in excess concentration to eliminate a corrosive factor, such as dissolved oxygen.

new source

any stationary source which is built or modified after publication of final or proposed regulations that prescribe a standard of performance which is intended to apply to that type of emission source.

new source performance standards (NSPS)

uniform national EPA air emission and water effluent standards which limit the amount of pollution allowed from new sources or from existing sources that have been modified.

new tank system

means a tank system that will be used to contain an accumulation of regulated substances and for which installation has commenced after December 22, 1988 (See also "Existing Tank System.")

NFA

No Further Action.

NFAN

National Filter Analysis Network.

NFMA

National Forest Management Act.

NFPA

National Fire Protection Association. An international voluntary membership organization to promote/improve fire protection and prevention and establish safeguards against loss of life and property by fire. Best known for the National Fire Codes, 16 volumes of standards, recommended practices, and manuals developed (and periodically updated) by NFPA communities. NFPA 704M publication is the code for showing hazards of materials using the familiar diamond-shaped label with appropriate numbers or symbols (NFPA hazard rating).

NFS

National Forest Service.

ng

Nanogram. One billionth, 10^^-9, of a gram.

NGA

National Governors Association.

NGPA

Natural Gas Policy Act.

NGWIC

National Ground Water Information Center.

NHANES

National Health and Nutrition Examination Study.

NHWP

Northeast Hazardous Waste Project.

NICS

National Institute for Chemical Studies.

NIEHS

National Institute of Environmental Health Sciences.

NIEI

National Indoor Environmental Institute.

NIH

National Institutes of Health.

NIM

National Impact Model.

NIMBY

Not In My Back Yard.

NIOSH

National Institute of Occupational Safety and Health. The agency of the Public Health Service that tests and certifies respiratory and air sampling devices. It recommends exposure limits to OSHA for substances, investigates incidents, and researches occupational safety.

NIPDWR

National Interim Primary Drinking Water Regulations.

NIS

Noise Information System.

NITEP

National Incinerator Testing and Evaluation Program.

Nitrate

a compound containing nitrogen which can exist in the atmosphere or as a dissolved gas in water and which can have harmful effects on humans and animals. Nitrates in water can cause severe illness in infants and cows.

nitric oxide (NO)

a gas formed by combustion under high temperature and high pressure in an internal combustion engine. It changes into nitrogen dioxide in the ambient air and contributes to photochemical smog.

nitrification

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

Nitrilotriacetic Acid (NTA)

a compound being used to replace phosphates in detergents.

nitrite

(1) an intermediate in the process of nitrification.(2) Nitrous oxide salts used in food preservation.

nitrogen dioxide (NOà)

the result of nitric oxide combining with oxygen in the atmosphere; a major component of photochemical smog.

nitrogen oxide (NOx)

product of combustion from transportation and stationary sources and a major contributor to the formation of ozone in the troposphere and acid deposition.

nitrogenous wastes

animal or plant residues that contain large amounts of nitrogen.

NJDEP

New Jersey Department of Environmental Protection.

NLAP

National Laboratory Audit Program.

NLM

National Library of Medicine.

NMFS

National Marine Fisheries Service.

NMHC

Nonmethane Hydrocarbons.

NMOC

Nonmethane Organic Compound.

NMP

National Municipal Policy.

NMR

Nuclear Magnetic Resonance.

NNC

Notice of Noncompliance.

NNPSPP

National Non-Point Source Pollution Program.

NO

a notation meaning oxides of nitrogen. See nitric oxide.

NOAA

National Oceanic and Atmospheric Administration.

NOAEL

No Observed Adverse Effect Level.

NOC

Not otherwise classified.

NODCC

Non Ozone Depleting Chlorinated Cleaners.

NOFOAM

Octal Alcohol No Foam (ETUS).

NOHSCP

National Oil and Hazardous Substances Contingency Plan.

NON

Notice of Noncompliance.

non-attainment areas

geographic area which does not meet one or more of the National Ambient Air Quality Standards for the criteria pollutants designated in the Clean Air Act.

noncarbonate hardness

hardness in water caused by chlorides, sulfates, and nitrates of calcium and magnesium.

noncommercial purposes

with respect to motor fuel means not for resale.

non-community water system

a public water system that is not a community water system, e.g., the water supply at a camp site or national park.

noncondensibles

gaseous material not liquefied when associated water vapor is condensed in the same environment.

non-conventional pollutant

any pollutant which is not a statutorily listed or which is poorly understood by the scientific community.

non-detects

chemicals that are not detected in a particular sample above a certain limit. This limit usually will be the quantitation limit for the chemical in that sample. (Note, however, that it is possible to detect and estimate concentrations of chemicals below the quantitation limit but above the detection limit.

nonflammable

incapable of being easily ignited or burning with extreme rapidity when lighted. Also, a DOT hazard class for any compressed gas other than a flammable one.

non-ionizing electromagnetic radiation

(1) radiation that does not change the structure of atoms but does heat tissue and may cause harmful biological effects. (2) Microwaves, radio waves, and low frequency electromagnetic fields from high voltage transmission lines.

non-liquefied compressed gas

DOT describes as a gas, other than gas in solution, which under the charged pressure is entirely gaseous at a temperature of 70¿F.

non-observed-adverse-effect-level (NOAEL)

in dose-response experiments, the experimental exposure level representing the highest level tested at which no adverse effects were demonstrated.

nonpoint source

pollution sources which are diffuse and do not have a single point of origin or are not introduced into a receiving stream from a specific outlet. The pollutants are generally carried off the land by stormwater runoff. The commonly used categories for non-point sources are: agriculture, forestry, urban, mining, construction, dams and channels, land disposal, and saltwater intrusion.

nonreactive silica

polymerized or colloidal silica.

nontransient noncommunity system

in contrast to the transient noncommunity systems described above, nontransient noncommunity water systems serve the same 25 people for at least six months a year.Examples include schools, factories, and other workplaces that have their own drinking water supply.

noise

any undesired sound.

no-observed-effect-level

in dose-response experiments, the experimental exposure level representing the highest level tested at which no effects at all were demonstrated.

NOPES

Non-Occupational Pesticide Exposure Study.

NORA

National Oil Recyclers Association.

NOS

National Ocean Survey.

Notification

refers to a process involving the dissemination of the emergency and informational messages provided to the public regarding a hazardous materials incident/accident. This notification process should follow the alert.

NOV

Notice of Violation.

NOx

nitrogen oxide; gases released primarily from the burning of fossil fuels; associated with breakdown of Earth's protective ozone layer.

NOV/C/D

Notice of Violation/Compliance/Demand.

NPAA

Noise Pollution and Abatement Act.

NPCA

National Paint and Coatings Association. The trade association of manufacturers that developed the HMIS labeling system. (1500 Rhode Island Avenue, NW., Washington, DC 20005; (202) 462-6272). See HMIS.

NPDES

National Pollutant Discharge Elimination System; federal permitting system required for hazardous effluents.

NPDWS

National Primary Drinking Water Standards.

NPIRES

National Pesticide Information Retrieval System.

NPL

National Priorities List; official list of hazardous waste sites to be addressed by CERCLA.

NPM

National Program Manager.

NPN

National Particulate Network.

NPR

Notice of Proposed Rulemaking.

NPS

National Park Service.

NPS

National Permit Strategy.

NPS

National Pesticide Survey.

NRC

Nuclear Regulatory Commission; National Response Center.

NRC

National Research Council.

NRC

National Response Center.

NRCA

National Resource Council of America.

NRDC

Natural Resources Defense Council.

NRT-1

National Response Team - 1 "Hazardous Materials Emergency Planning Guide"

NRT-2

National Response Team - 2 "Developing a Hazardous Materials Exercise Program"

NRWA

National Rural Water Association.

NSDWR

National Secondary Drinking Water Regulations.

NSF

National Strike Force (SARA); National Sanitation Foundation.

NSF

National Sanitation Foundation.

NSF

National Science Foundation.

NSPE

National Society for Professional Engineers.

NSPS

New Source Performance Standards; air emissions standards under CAA for new air pollutions sources.

NSSC

the neutral sulfite, semichemical pulping process.

NSWMA

National Solid Waste Management Association.

NSWS

National Surface Water Survey.

NTA

nitrilotriacetic acid, a chelant with the sodium salt being the usual form.

NTA

Negotiated Testing Agreement.

NTGS

National Technical Guidance Studies.

NTIS

National Technical Information Service.

NTP

National Toxicology Program. Federal activity overseen by the Department of Health and Human Services with resources from National Institutes of Health, the Food and Drug Administration, and the Center for Disease Control. Its goals are to develop tests useful for public health regulations of toxic chemicals, to develop toxicological profiles of materials, to foster testing of materials, and to communicate the results for use by others.(NTP Information Office, MD B2-04, Box 12233, Research Triangle Park, NC 27709).

NTSB

National Transportation Safety Board.

nuisance particulates

dusts that do not produce significant organic disease or toxic effects from "reasonable" concentrations and exposures. TLV of 10 mg/m3 or 30 mppcf.

nuclear power plant

a device that converts atomic energy into usable power; heat produced by a reactor makes steam to drive electricity-generated turbines.

nuclear winter

prediction by some scientists that smoke and debris rising from massive fires resulting from a nuclear war could enter the atmosphere and block out sunlight for weeks or months. The scientists making this prediction project a cooling of the earth's surface, and changes in climate which could, for example, negatively effect world agricultural and weather patterns.

nutrients

elements or compounds essential to growth and development of living things; carbon, oxygen, nitrogen, potassium and phosphorus.

NWA

National Water Alliance.

NWF

National Wildlife Federation.

NWPA

Nuclear Waste Policy Act.

NWS

National Weather Service.

nystagmus

spastic, involuntary motion of the eyeballs.

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