Copy of `EPA - Environmental Terms Glossary`

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EPA - Environmental Terms Glossary Category: Earth and Environment Date & country: 13/09/2007, USA Words: 1829

Passive Treatment Walls
Technology in which a chemical reaction takes place when contaminated ground water comes in contact with a barrier such as limestone or a wall containing iron filings.

Pathogens
Microorganisms (e.g., bacteria, viruses, or parasites) that can cause disease in humans, animals and plants.

Pathway
The physical course a chemical or pollutant takes from its source to the exposed organism.

Pay-As-You-Throw-Unit-Based Pricing
Systems under which residents pay for municipal waste management and disposal services by weight or volume collected, not a fixed fee.

Peak Electricity Demand
The maximum electricity used to meet the cooling load of a building or buildings in a given area.

Peak Levels
Levels of airborne pollutant contaminants much higher than average or occurring for short periods of time in response to sudden releases.

Percent Saturatiuon
The amount of a substance that is dissolved in a solution compared to the amount that could be dissolved in it.

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

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

Percolation
1. The movement of water downward and radially through subsurface soil layers, usually continuing downward to ground water. Can also involve upward movement of water. 2. Slow seepage of water through a filter.

Performance Bond
Cash or securities deposited before a landfill operating permit is issued, which are held to ensure that all requirements for operating ad subsequently closing the landfill are faithful performed. The money is returned to the owner after proper closure of the landfill is completed. If contamination or other problems appear at any time during operation, or upon closure, and are not addressed, the owner must forfeit all or part of the bond which is then used to cover clean-up costs.

Performance Data (For Incinerators)
Information collected, during a trial burn, on concentrations of designated organic compounds and pollutants found in incinerator emissions. Data analysis must show that the incinerator meets performance standards under operating conditions specified in the RCRA permit. (See trial burn; performance standards.)

Performance Standards
1. Regulatory requirements limiting the concentrations of designated organic compounds, particulate matter, and hydrogen chloride in emissions from incinerators. 2. Operating standards established by EPA for various permitted pollution control systems, asbestos inspections, and various program operations and maintenance requirements.

Periphyton
Microscopic underwater plants and animals that are firmly attached to solid surfaces such as rocks, logs, and pilings.

Permeability
The rate at which liquids pass through soil or other materials in a specified direction.

Permissible Dose
The dose of a chemical that may be received by an individual without the expectation of a significantly harmful result.

Permissible Exposure Limit
Also referred to as PEL, federal limits for workplace exposure to contaminants as established by OSHA.

Permit
An authorization, license, or equivalent control document issued by EPA or an approved state agency to implement the requirements of an environmental regulation; e.g. a permit to operate a wastewater treatment plant or to operate a facility that may generate harmful emissions.

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

Persistent Pesticides
Pesticides that do not break down chemically or break down very slowly and remain in the environment after a growing season.

Personal Air Samples
Air samples taken with a pump that is directly attached to the worker with the collecting filter and cassette placed in the worker's breathing zone (required under OSHA asbestos standards and EPA worker protection rule).

Personal Measurement
A measurement collected from an individual's immediate environment.

Personal Protective Equipment
Clothing and equipment worn by pesticide mixers, loaders and applicators and re-entry workers, hazmat emergency responders, workers cleaning up Superfund sites, et. al., which is worn to reduce their exposure to potentially hazardous chemicals and other pollutants.

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

Pest Control Operator
Person or company that applies pesticides as a business (e.g. exterminator); usually describes household services, not agricultural applications.

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

Pesticide Regulation Notice
Formal notice to pesticide registrants about important changes in regulatory policy, procedures, regulations.

Pesticide Tolerance
The amount of pesticide residue allowed by law to remain in or on a harvested crop. EPA sets these levels well below the point where the compounds might be harmful to consumers.

PETE (Polyethylene Terepthalate)
Thermoplastic material used in plastic soft drink and rigid containers.

Petroleum
Crude oil or any fraction thereof that is liquid under normal conditions of temperature and pressure. The term includes petroleum-based substances comprising a complex blend of hydrocarbons derived from crude oil through the process of separation, conversion, upgrading, and finishing, such as motor fuel, jet oil, lubricants, petroleum solvents, and used oil.

Petroleum Derivatives
Chemicals formed when gasoline breaks down in contact with ground water.

pH
An expression of the intensity of the basic or acid condition of a liquid; may range from 0 to 14, where 0 is the most acid and 7 is neutral. Natural waters usually have a pH between 6.5 and 8.5.

Pharmacokinetics
The study of the way that drugs move through the body after they are swallowed or injected.

Phenolphthalein Alkalinity
The alkalinity in a water sample measured by the amount of standard acid needed to lower the pH to a level of 8.3 as indicated by the change of color of the phenolphthalein from pink to clear.

Phenols
Organic compounds that are byproducts of petroleum refining, tanning, and textile, dye, and resin manufacturing. Low concentrations cause taste and odor problems in water; higher concentrations can kill aquatic life and humans.

Phosphates
Certain chemical compounds containing phosphorus.

Phosphogypsum Piles (Stacks)
Principal byproduct generated in production of phosphoric acid from phosphate rock. These piles may generate radioactive radon gas.

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

Phosphorus Plants
Facilities using electric furnaces to produce elemental phosphorous for commercial use, such as high grade phosphoric acid, phosphate-based detergent, and organic chemicals use.

Photochemical Oxidants
Air pollutants formed by the action of sunlight on oxides of nitrogen and hydrocarbons.

Photochemical Smog
Air pollution caused by chemical reactions of various pollutants emitted from different sources. (See photochemical oxidants.)

Photosynthesis
The manufacture by plants of carbohydrates and oxygen from carbon dioxide mediated by chlorophyll in the presence of sunlight.

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

Phytoplankton
That portion of the plankton community comprised of tiny plants; e.g. algae, diatoms.

Phytoremediation
Low-cost remediation option for sites with widely dispersed contamination at low concentrations.

Phytotoxic
Harmful to plants.

Phytotreatment
The cultivation of specialized plants that absorb specific contaminants from the soil through their roots or foliage. This reduces the concentration of contaminants in the soil, but incorporates them into biomasses that may be released back into the environment when the plant dies or is harvested.

Picocuries Per Liter pCi-L)
A unit of measure for levels of radon gas; becquerels per cubic meter is metric equivalent.

Piezometer
A nonpumping well, generally of small diameter, for measuring the elevation of a water table.

Pilot Tests
Testing a cleanup technology under actual site conditions to identify potential problems prior to full-scale implementation.

Plankton
Tiny plants and animals that live in water.

Plasma Arc Reactors
devices that use an electric arc to thermally decompose organic and inorganic materials at ultra-high temperatures into gases and a vitrified slag residue. A plasma arc reactor can operate as any of the following:

Plasmid
A circular piece of DNA that exists apart from the chromosome and replicates independently of it. Bacterial plasmids carry information that renders the bacteria resistant to antibiotics. Plasmids are often used in genetic engineering to carry desired genes into organisms.

Plastics
Non-metallic chemoreactive compounds molded into rigid or pliable construction materials, fabrics, etc.

Plate Tower Scrubber
An air pollution control device that neutralizes hydrogen chloride gas by bubbling alkaline water through holes in a series of metal plates.

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

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

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

Plutonium
A radioactive metallic element chemically similar to uranium.

PM-10-PM-2.5
PM 10 is measure of particles in the atmosphere with a diameter of less than ten or equal to a nominal 10 micrometers. PM-2.5 is a measure of smaller particles in the air. PM-10 has been the pollutant particulate level standard against which EPA has been measuring Clean Air Act compliance. On the basis of newer scientific findings, the Agency is considering regulations that will make PM-2.5 the new 'standard'.

Pneumoconiosis
Health conditions characterized by permanent deposition of substantial amounts of particulate matter in the lungs and by the tissue reaction to its presence; can range from relatively harmless forms of sclerosis to the destructive fibrotic effect of silicosis.

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

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

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

Pollen
The fertilizing element of flowering plants; background air pollutant.

Pollutant
Generally, any substance introduced into the environment that adversely affects the usefulness of a resource or the health of humans, animals, or ecosystems..

Pollutant Pathways
Avenues for distribution of pollutants. In most buildings, for example, HVAC systems are the primary pathways although all building components can interact to affect how air movement distributes pollutants.

Pollutant Standard Index (PSI)
Indicator of one or more pollutants that may be used to inform the public about the potential for adverse health effects from air pollution in major cities.

Pollution
Generally, the presence of a substance in the environment that because of its chemical composition or quantity prevents the functioning of natural processes and produces undesirable environmental and health effects.Under the Clean Water Act, for example, the term has been defined as the man-made or man-induced alteration of the physical, biological, chemical, and radiological integrity of water and other media.

Pollution Prevention
1. Identifying areas, processes, and activities which create excessive waste products or pollutants in order to reduce or prevent them through, alteration, or eliminating a process. Such activities, consistent with the Pollution Prevention Act of 1990, are conducted across all EPA programs and can involve cooperative efforts with such agencies as the Departments of Agriculture and Energy. 2. EPA has initiated a number of voluntary programs in which industrial, or commercial or 'partners' join wi…

Polonium
A radioactive element that occurs in pitchblende and other uranium-containing ores.

Polychlorinated Biphenyls
A group of toxic, persistent chemicals used in electrical transformers and capacitors for insulating purposes, and in gas pipeline systems as lubricant. The sale and new use of these chemicals, also known as PCBs, were banned by law in 1979.

Polyelectrolytes
Synthetic chemicals that help solids to clump during sewage treatment.

Polymer
A natural or synthetic chemical structure where two or more like molecules are joined to form a more complex molecular structure (e.g. polyethylene in plastic).

Polyvinyl Chloride (PVC)
A tough, environmentally indestructible plastic that releases hydrochloric acid when burned.

Population
A group of interbreeding organisms occupying a particular space; the number of humans or other living creatures in a designated area.

Population at Risk
A population subgroup that is more likely to be exposed to a chemical, or is more sensitive to the chemical, than is the general population.

Porosity
Degree to which soil, gravel, sediment, or rock is permeated with pores or cavities through which water or air can move.

Post-Chlorination
Addition of chlorine to plant effluent for disinfectant purposes after the effluent has been treated.

Post-Closure
The time period following the shutdown of a waste management or manufacturing facility; for monitoring purposes, often considered to be 30 years.

Post-Consumer Materials-Waste
Recovered materials that are diverted from municipal solid waste for the purpose of collection, recycling, and disposition.

Post-Consumer Recycling
Use of materials generated from residential and consumer waste for new or similar purposes; e.g. converting wastepaper from offices into corrugated boxes or newsprint.

Potable Water
Water that is safe for drinking and cooking.

Potential Dose
The amount of a compound contained in material swallowed, breathed, or applied to the skin.

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

Potentiation
The ability of one chemical to increase the effect of another chemical.

Potentiometric Surface
The surface to which water in an aquifer can rise by hydrostatic pressure.

Pre-Consumer Materials-Waste
Materials generated in manufacturing and converting processes such as manufacturing scrap and trimmings and cuttings. Includes print overruns, overissue publications, and obsolete inventories.

Pre-Harvest Interval
The time between the last pesticide application and harvest of the treated crops.

Precautionary Principle
When information about potential risks is incomplete, basing decisions about the best ways to manage or reduce risks on a preference for avoiding unnecessary health risks instead of on unnecessary economic expenditures.

Prechlorination
The addition of chlorine at the headworks of a treatment plant prior to other treatment processes. Done mainly for disinfection and control of tastes, odors, and aquatic growths, and to aid in coagulation and settling,

Precipitate
A substance separated from a solution or suspension by chemical or physical change.

Precipitation
Removal of hazardous solids from liquid waste to permit safe disposal; removal of particles from airborne emissions as in rain (e.g. acid precipitation).

Precipitator
Pollution control device that collects particles from an air stream.

Precursor
In photochemistry, a compound antecedent to a pollutant. For example, volatile organic compounds (VOCs) and nitric oxides of nitrogen react in sunlight to form ozone or other photochemical oxidants. As such, VOCs and oxides of nitrogen are precursors.

Preliminary Assessment
The process of collecting and reviewing available information about a known or suspected waste site or release.

Prescriptive
Water rights which are acquired by diverting water and putting it to use in accordance with specified procedures; e.g. filing a request with a state agency to use unused water in a stream, river, or lake.

Pressed Wood Products
Materials used in building and furniture construction that are made from wood veneers, particles, or fibers bonded together with an adhesive under heat and pressure.

Pressure Sewers
A system of pipes in which water, wastewater, or other liquid is pumped to a higher elevation.

Pressure, Static
In flowing air, the total pressure minus velocity pressure, pushing equally in all directions.