Environmental Terms Glossary
P-Q
PAPR
Powered Air-Purifying Respirator
Pathways of Dispersion
A substance when released into the environment tends to accumulate on land, in air, in water, or in organic matter.
PCB
Polychlorinatd Biphenols. A pathogenic and teratogenic industrial compound used as a heat-transfer agent.
PEL
Permissible Exposure Limit (OSHA)
Permeation
Seepage of a chemical through a material.
Permit
An authorization, license, or equivalent control document issued by EPA or an approved State agency to implement the requirements of an environmental regulation.
Permit Issuing Authority
The State agency or EPA Regional office which issues environmental permits to regulated facilities.
Personal Protective Equipment (PPE)
Clothing and equipment, which has full-face respirators, plastic coveralls, and gloves, used to minimize contaminant inhalation, ingestion, and/or contact with undesirable materials.
Petroleum Hydrocarbons
Petroleum organic compounds that contain carbon and hydrogen only.
PF
Protection Factor. Refers to the level of protection a respiratory protective device offers.
pH
Acidity or alkalinity of the discharge water.
PHE
Public Health Evaluation
PHSA
Public Health Service Act
pK
The negative logarithm of the equilibrium constant, K, for reactions. This constant can be used to indicate the strength of an acid or a base.
Plume
The elongated pattern of contamination spreading from the source of pollution into the environment.
PMN
Pre-Manufacturing Notices
Point Source
Any discernible, confined, and discrete conveyance, including but not limited to, any pipe, ditch, channel, tunnel, conduit, well, discrete fissure, container, rolling stock, concentrated animal feeding operation, landfill leachate collection system, vessel or other floating craft from which pollutants are or may be discharges. This term does not include return flows from irrigated agriculture or agricultural storm water runoff.
Poisons
Materials which cause harm to living organisms either through inhalation, absorption, injection, or skin contact.
Pollutant
Legally, any dredged spoil, solid waste, incinerator residue, filter backwash, sewage, garbage sewage sludge, munitions, chemical wastes, biological materials, radioactive materials (except those regulated under the Atomic Energy Act, heat, wrecked or discharged into water. From a practical perspective, any substance or mixture which after release into the environment and upon exposure to any organism will or may reasonable be anticipated to cause adverse effects in such organisms or their offspring.
Polymerization
A chemical reaction usually carried out with a catalyst, heat, or light, and often under high pressure, in which a large number of simple molecules combine to form a much larger chain-like macromolecule.
Potential Hydrogen (pH)
A value that will represent the acidity or the alkalinity of an aqueous solution. Solutions with a pH of 7 are considered to be neutral. Acids have a pH of less than 7 and bases have a pH of greater than 7. The farther away from 7 on the 0-14 scale, the stronger the acid or base. This scale does not determine the concentration of the solution, therefore more information is needed to make appropriate response decisions.
POTW
Publicly Owned Treatment Works. Any device or system used in the treatment (including recycling and reclamation) of municipal sewage or industrial wastes of a liquid nature which is owned by a state or municipality.
PPA
Pollution Prevention Act of 1990
PPB
Parts Per Billion. The unit commonly used to represent the degree of pollutant concentration where the concentrations are small. In air, ppm is usually a volume/volume ratio; in water, a weight/volume ratio.
PPC
Personal Protective Clothing
PPE
Personal Protective Equipment. Clothing and equipment, such as full-face respirators, plastic coveralls, and gloves, used to minimize contaminant inhalation, ingestion, and/or contact with undesirable materials.
PPM
Parts Per Million (10,000 ppm = 1 percent)
PPPA
Poison Prevention Packaging Act (1970)
Pressure-Demand Respirator
A respiratory protection device that supplies air to the user. It maintains a slight positive pressure in the facepiece at all times, and supplies additional air in response to the negative pressure created by inhalation.
Pretreatment System
A treatment system designed to remove gross contamination in order to increase the efficiency of the following treatment steps.
Preventative Maintenance Program
A schedule of inspections and testing at regular intervals intended to prevent equipment failures and deterioration.
Process Wastewater
Water that comes into direct contact with or results from the production or use of any raw material, intermediate product, finished product, by-product, waste product, or wastewater.
Protection Factor (FP)
The ratio of the ambient concentration of an airborne substance to the concentration of the substance inside the respirator at the breathing zone of the wearer. The PF is a measure of the degree of protection that the respirator offers. MUC = PF X PEL.
PRP
Potentially Responsible Party. Any individual or company - including owners, operators, transporters, or generators of hazardous substances - potentially responsible for, or contributing to contamination at a hazardous substances release site.
PSD
Prevention of Significant Deterioration
PSD
Prevention of Significant Deterioration (of air quality)
psi
Pounds Per Square Inch
psia
Pounds per square inch absolute
psig
Pounds per square inch gauge
Pyrophoric
A chemical that will ignite spontaneously in air at a temperature of 130 degrees F or below.
Q
QA/AC
Quality Assurance/Quality Control
R
R
A symbol used to represent an organic group in a chemical formula.
RA
Remedial Action. The actual construction or implementation phase that follows the remedial design of the selected cleanup alternative at a site.
RACT
Reasonably Available Control Technology
RAD
A unit for measurement of radioactivity. One RAD is the amount of radiation that results in the absorption of 100 ergs of energy by 1 g of material.
Radioactivity
The amount of ionizing radiation emitted spontaneously by a material, generally in three basic forms: alpha, beta, (both of which are particulate form) and gamma (which is an electromagnetic wave that is the most dangerous from an exposure standpoint because of the difficulty of protecting oneself from it).
RAM
Real-Time Air-Quality Simulation Model
RAM
Radioactive Material
RAP
Remedial Action Plan
RBE
Relative Biological Effectiveness. A measure of the relative effectiveness of absorbed doses of radiation.
RCRA
Resource Conservation and Recovery Act. Regulates management and disposal of hazardous materials and wastes being generated, treated, stored, disposed or distributed.
RD
Remedial Design
Recycle
The process of minimizing the generation of waste by recovering usable products that might otherwise become waste.
Regulated Area
The subject upon which the storm water regulations or other appropriate rules are applied.
REL
Recommended Exposure Limit
Relation To Ventilation
Known ACM is located near an air plenum, air shafts, or vents that attribute to erosion and/or migration of fibers to other areas of the building.
Relative Biological Effectiveness (RBE)
A measure of the relative effectiveness of absorbed doses of radiation.
REM
Roentgen Equivalent Man. A measure of radiation dose.
Remedial Action Plan
Document that provides information on the proposed clean-up of a contaminated site.
Remedial Design
An engineering phase that follows the Record of Decision when technical drawings and specifications are developed for the subsequent remedial action at a site on the National Priorities List.
Remedial Design Work Plan
Provides detailed design information and engineering specifications about the recommended remedial alternatives for clean-up of a hazardous substances release site.
Remedial Investigation
A study which includes the collection and analysis of soil, groundwater and air samples which assess the nature and extent of contamination at a site.
Remedial Investigation/Feasibility Study
Two distinct but related studies. They are usually performed at the same time, and together referred to as the "RI/FS". They are intended to gather the data necessary to determine the type and extent of contamination at a Superfund site; establish criteria for cleaning up the site; identify and screen cleanup alternatives for remedial action; and analyze in detail the technology and costs of the alternatives.
Remediation
Correction or clean-up of environmental contamination.
Remediation Action
The actual construction or implementation phase that follows the remedial design of the selected cleanup alternative at the site.
Reportable Quantity (RQ)
The quantity of a hazardous substance or oil that triggers reporting requirements under CERCLA or the CWA. If a substance is released in amounts exceeding its RQ, the release must be reported to the National Response Center, the State Emergency Response commission, and community emergency coordinators for areas likely to be affected.
Residual
Amount of pollutant remaining in the environment after a natural or technological process has taken place, e.g., the sludge remaining after initial wastewater treatment.
Residue
As related to Title 49 CFR 171.8, residue is the hazardous material remaining in a packaging after its contents have been emptied and before the packaging is refilled, or cleaned and purged of vapor to remove any potential hazard.
Resource Conservation and Recovery Act
Regulates management and disposal of hazardous materials and wastes being generated, treated, stored, disposed or distributed.
See Also: RCRA
Retention
The holding of runoff in a basin without release except by means of evaporation, infiltration, or emergency by-pass.
Retrofit
The modification of storm water management systems in developed areas through the construction of wet ponds, infiltration systems, wetland plantings, stream bank stabilization, and other BMP techniques for improving water quality. A retrofit can consist of the construction of a new BMP in the developed area, the enhancement of an older storm water management structure, or a combination of improvement and new construction.
RHAA
Rivers and Harbors Appropriations Act (1899)
RI
Remedial Investigation
Risk Assessment
An investigation of the potential risk to human health or the environment posed by a specific action or substance.
Risk/Exposure
The potential threat to human health or the environment that results from the release or handling of wastes or sensitive materials.
RI/FS
Remedial Investigation/Feasibility Study
ROD
Record of Decision. A public document that explains which cleanup alternative(s) will be used at National Priorities List sites. The Record of Decision is based on information and technical analysis generated during the remedial investigation/feasibility study and consideration of public comments and community concerns.
Roentgen
A measure of the charge produced as the rays pass through the air.
RPAR
Rebuttable Presemption Against Registration
RQ
Reportable Quantity
RSPA
Research and Special Programs Administration
RTK
Right To Know
Runoff
Storm water surface flow or the surface which leaves the property from which it originated.
Runon
Storm water surface flow or other surface flow which enters property other than where it originated.
RVP
Reid Vapor Pressure
S
SADT
Self-Accelerating Decomposition Temperature Test
Safe Drinking Water Act
Establishes maximum contaminant levels for drinking water.
See Also: SDWA
Salt
The compound formed when a metal and a non-metal ionically bond together. The neutralization process of acids and bases forms water and a salt.
Salvage Drum
A drum with a removable metal head used to transport damaged or leaking hazardous materials, containers, and their contents for repackaging or disposal.
Sanitary Sewer
A system of underground pipes that carries sanitary waste or process wastewater to a treatment plant.
Sanitary Waste
Domestic sewage.
SAR
Supplied Air Respirator
SARA
Superfund Amendments and Reauthorization Act. A federal law enacted in 1986 reauthorizing and expanding the jurisdiction of CERCLA.
SARA Title III
Detail requirements for annual public disclosure by industry of chemical information, and development of state and local emergency response plans.
Satellite Location
A point of generation for hazardous waste before placing it in a central storage facility and starting the 90 day holding period.
Saturated Hydrocarbons
A hydrocarbon in the state in which all available valence bonds are attached to hydrogen atoms rather than combining with themselves with double, triple, or resonant bonds. The straight chained hydrocarbons are typically saturated hydrocarbons.
Saturation
(1) Occurs when a solution contains the highest possible concentration of a solute at a given temperature. (2) The state in which all valence bonds of an atom are attached to other atoms.
SCBA
Self-Contained Breathing Apparatus
SDWA
Safe Drinking Water Act (1974)
Secondary Containment
Structures usually dikes, or berms, surrounding tanks or other storage containers and designed to catch spilled material from the storage containers.
Secondary Materials
Spent materials, sludges, by-products, scrap metal and commercial chemical products recycled in ways that differ from their normal use.
Section 313 Water Priority Chemical
A chemical or chemical category(ies) which:
- is listed at 40 CFR 372.65 pursuant to Section 313 of the Emergency Planning and Community Right-to-Know Act (EPCRA; also known as Title III of the Superfund Amendments and Reauthorization Act of 1986);
- is present at or above threshold levels at a facility subject to EPCRA Section 313 reporting requirements; and
- that meets at least one of the following criteria:
- listed in Appendix D of 40 CFR 122 on either Table II (organic pollutants), Table III (certain metals, cyanides, and phenols) or Table V (certain toxic pollutants and hazardous substances);
- listed as a hazardous substance pursuant to section 311(b)(2)(A) of the CWA at 40 CFR 116.4; or
- are pollutants for which EPA has published acute or chronic water quality criteria.
Sediment
Solid material, both mineral and organic, that is in suspension, is being transported, or has moved from its site of origin by air, water or ice, and has come to rest on earth's surface.
Sediment Trap
A device for removing sediment fro water flows; usually installed at outfall points.
Sedimentation
The process of depositing soil particles, clays, sands, or other sediments that were picked up by flowing water.
Sediments
Soil, sand, and minerals washed from land into water, usually after rain. They pile up in reservoirs, rivers, and harbors, destroying fish-nesting areas and holes of water animals and cloud the water so that needed sunlight might not reach aquatic plants.
Self-Accelerating Decomposition Temperature (SADT)
The temperature at which the decomposition of a molecule becomes self-feeding and irreversible. Once a material reaches this temperature, it will decompose with explosive force.
Self-Contained Breathing Apparatus (SCBA)
A respiratory protection device that supplies clean air to the user from a compressed air source carried by the user.
Sensitizer
A substance which on first exposure causes little or no reaction in man or test animals but which on repeated exposure may cause a marked response not necessarily limited to the contact site.
Sensitive Materials
Any products or potentially hazardous supplies that can pose a health risk to humans or threat to the environment.
SERC
State Emergency Response Commission
Sheet Flow
Runoff which flows over the ground surface as a thin, even layer, and is not concentrated in a channel or other conveyance.
Shelf Life
The time for which chemicals and other materials can be stored before becoming unusable due to age or deterioration.
SIC
Standard Industrial Classification
Sievert (Sv)
A unit for measuring the amount of radiation that a biological system can absorb, defined as absorbed radiation dose times the quality factor of the radiation as compared to gammaradiation. One Sievert is equal to 100 REM and will soon replace the REM.
Significant Material
Raw materials; fuels; materials such as solvents, detergents and plastic pellets; finished materials such as metallic products; raw materials used in food processing or production; hazardous substances designated under section 101(14) CERCLA; any chemical the facility is required to report pursuant to section 313, SARA of Title III; fertilizers; pesticides; and waste products such as ashes, slag, and sludge that have a potential to be released with storm water discharges.
Significant New Use Rule (SNUR)
Stipulation (applied as criterion for manufacture of a specific chemical) that EPA must be notified of significant new use of the chemical.
Significant Railroad Material
Significant material which is commonly or frequently found at railroad maintenance facilities, including but not limited to fuel oils, used oil, greases, lubricants, hydraulic fluids, cleaners and detergents, paints and paint thinners, solvents, and similar materials which could pose significant potential for storm water pollution if not effectively controlled.
Significant Spills
Releases of oil or hazardous substances in excess of reportable quantities under section 311 of the Clean Water Act (see 40 CFR 110.10 and CFR 117.21) or section 102 of CERCLA (see 40 CFR 302.4).
SIP
State Implementation Plan
SITE
Superfund Innovative Technology Evaluation program
Skin
A notation, sometimes used with PEL or TLV exposure data; indicates that the stated substance may be absorbed by the skin, mucous membranes and eyes - either airborne or by direct contact - and that this additional exposure must be considered part of the total exposure to avoid exceeding the PEL or TLV for that substance.
Sludges
High solids content suspensions, sludges, or residues usually resultant from treating air or waste water or other residues from pollution control operations.
Slurry
A thin, water solution with solids suspended in it. Some blasting agents are considered to be slurries.
SMCL
Secondary MCL
SMCRA
Surface Mining Control and Reclamation Act of 1977
Smoke
An air suspension or particles, often originating from combustion or sublimation.
SNUR
Significant New Use Rule
SOCMI
Synthetic Organic Chemical Manufacturing Industry
Solid Waste
Any garbage, refuse or sludge, including solid, liquid, semisolid or contained gaseous material resulting from industrial, commercial, agricultural or mining operations, or community activities; excluding material in domestic sewage, discharges subject to regulation as point sources under Federal Water Pollution Control Act, or any nuclear material or byproduct regulated under the Atomic Energy Act of 1954.
Solubility
The ability or tendency of one substance to blend uniformly with another substance.
Solution
A mixture containing one or more substances dissolved (the solute) into one or more substances (the solvent).
Solvent
A liquid capable of dissolving another substance.
SOP
Standard Operating Procedure
Sorbent Material
A substance that takes up other materials either by absorption or adsorption.
Source Control
A practice or structural measure to prevent pollutants from entering storm water runoff or other environmental media.
SPA
Shore Protection Act (1988)
SPCC
Spill Prevention Control and Countermeasure. A plan to reduce or minimize the introduction and subsequent discharge of pollutants in storm water discharges. Such plans are required by storm water regulations.
Specific Gravity
The ratio of the density of a liquid or solid to the density of water. Water, being the reference substance, will equal one. Products with a specific gravity less than 1 will tend to float on water. Those with a specific gravity greater than 1 will sink in water.
Spent Solvent
A liquid solution that has been used and is no longer capable of dissolving solids, gases, or liquids.
SpG
Specific Gravity
Spill Guard
A device used to prevent spills of liquid materials from storage containers.
SRP
Spill Response Plan
SSSHP
Site-Specific Safety and Health Plan
Standard Operating Procedures (SOP)
Established or prescribed tactical or administrative methods to be followed routinely for the performance of designated operations or in designated situations.
STC
Single Tip Container
STEL
Short-Term Exposure Limit
Storage
When used in connection with hazardous waste, means the containment of hazardous waste, either on a temporary basis or for a period of years, in such a manner as not to constitute disposal of such hazardous waste.
Storage Tank
Any manufactured, nonportable, covered device used for containing pumpable hazardous wastes.
Storm Drain
Opening, usually slotted, leading to an underground pipe or an open ditch for carrying surface runoff.
Storm Water
Runoff resulting directly or indirectly from a storm event or snow melt runoff.
Storm Water Discharge
The discharge from any conveyance which is used for collecting and conveying storm water.
Storm Water Discharge Permit
An NPDES permit issued by EPA or delegated state to discharge storm waters. Non-delegated states may have other required state-issued (non-NPDES) permits for discharge of storm waters.
Storm Water Regulations
Federal and corresponding (if any) state regulations which regulate the point source discharge of storm waters.
Storm Water Sewer System
A conveyance system which conveys storm waters.
Strength
The level of reaction of a particular acid or base. Acids in the pH 1-2 range are thought to be strong acids, while bases in the 13-14 range are strong bases. This term does not define the amount of acid or base in the solution just the particular level of reaction. Therefore, the terms strong and concentrated are in no way synonymous.
Strict Liability
The defendant may be liable even though he may have exercised reasonable care.
Sublimation
The passage of a substance from the solid state directly to the vapor state without passing through the liquid state. Examples: Carbon Dioxide (dry ice), moth balls.
Substantially Identical Outfalls
Storm water discharges for which the following characteristics are closely similar: occurrence of pollutants; runoff characteristics; and materials present and exposed to storm waters in the area from which the discharges come.
Sump
A pit or tank that catches liquid runoff for drainage or disposal.
Superfund
Funds set up to help pay for cleanup of hazardous waste sites and to take legal action to force responsible parties to clean them up.
Supplied Air Respirator
A respiratory protection device that supplies air to the user from a source that is not worn by the user but is connected to the user by a hose. Also called an air-line respirator.
Support Zone (SZ)
The uncontaminated area of a site where workers will not be exposed to hazardous conditions.
Surface Impoundment
Any natural depression or excavated and/or diked area built into or upon the land, which is fixed, uncovered, and lined with soil or a synthetic material, and is used for treating, storing or disposing wastes.
Surface Tension
The inward pull or internal pressure of a liquid that tends to restrain the liquid from flowing. Liquids with low surface tensions tend to flow readily (I.e. benzene). Those with high surface tensions do not flow as well, if at all, which is the case with mercury.
Surface Water
Any body of water that is above ground, such as a river, lake, reservoir, estuary, pond, creek or stream.
Swale
An elongated depression in the land surface that is at least seasonally wet, is commonly vegetated, and is normally without flowing water except during storm event periods. Sales direct storm water flows into primary drainage channels and allow some of the storm water to infiltrate into the ground surface; vegetation may also promote biological changes in flowing water containments.
SWDA
Solid Waste Disposal Act
SWMU
Solid Waste Management Units
SWPPP
Storm Water Pollution Prevention Plan. A plan to reduce or minimize the introduction and subsequent discharge of pollutants in storm water discharges. Such plans are required by storm water regulations.
SWTCP
Surface Water Toxic Controls Program
Synergism
Cooperative action of substances whose total effect is greater than the sum of their separate effects.
SZ
Support Zone