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Glossary: P
Packaging:
The assembly of one or more containers and any other components necessary to
ensure minimum compliance with a program's storage and shipment packaging
requirements. Also, the containers, etc. involved.
Packed Bed Scrubber:
An air pollution control device in which emissions pass through alkaline water
to neutralize hydrogen chloride gas.
Packed Tower:
A pollution control device that forces dirty air through a tower packed with
crushed rock or wood chips while liquid is sprayed over the packing material.
The pollutants in the air stream either dissolve or chemically react with the
liquid.
Packer:
An inflatable gland, or balloon, used to create a temporary seal in a borehole,
probe hole, well, or drive casing. It is made of rubber or non-reactive
materials.
PAHs:
Polycyclic aromatic hydrocarbons (PAHs) are a group of over 100 different
chemicals that are formed during the incomplete burning of coal, oil and gas,
garbage, or other organic substances like tobacco or charbroiled meat. PAHs are
usually found as a mixture containing two or more of these compounds, such as
soot.
Some PAHs are manufactured. These pure PAHs usually exist as colorless, white,
or pale yellow-green solids. PAHs are found in coal tar, crude oil, creosote,
and roofing tar, but a few are used in medicines or to make dyes, plastics, and
pesticides.
Palatable Water:
Water, at a desirable temperature, that is free from objectionable tastes,
odors, colors, and turbidity.
Pandemic:
A widespread epidemic throughout an area, nation or the world.
Paper:
In the recycling business, refers to products and materials, including
newspapers, magazines, office papers, corrugated containers, bags and some
paperboard packaging that can be recycled into new paper products.
Parameter:
A variable, measurable property whose value is a determinant of the
characteristics of a system; e.g. temperature, pressure, and density are
parameters of the atmosphere.
Paraquat:
A standard herbicide used to kill various types of crops, including marijuana.
Causes lung damage if smoke from the crop is inhaled..
Parshall Flume:
Device used to measure the flow of water in an open channel.
Part A Permit, Part B Permit:
(See: Interim Permit Status.)
Participation Rate:
Portion of population participating in a recycling program.
Particle Count:
Results of a microscopic examination of treated water with a special "particle
counter" that classifies suspended particles by number and size.
Particulate Loading:
The mass of particulates per unit volume of air or water.
Particulates:
1. Fine liquid or solid particles such as dust, smoke, mist, fumes, or smog,
found in air or emissions. 2. Very small solids suspended in water; they can
vary in size, shape, density and electrical charge and can be gathered together
by coagulation and flocculation.
Partition Coefficient:
Measure of the sorption phenomenon, whereby a pesticide is divided between the
soil and water phase; also referred to as adsorption partition coefficient.
Parts Per Billion (ppb)/Parts Per Million (ppm):
Units commonly used to express contamination ratios, as in establishing the
maximum permissible amount of a contaminant in water, land, or air.
Passive Smoking/Secondhand Smoke:
Inhalation of others' tobacco smoke.
Passive Treatment Walls:
Technology in which a chemical reaction takes place when contaminated
groundwater 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 Saturation:
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 groundwater. 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 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 USEPA 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 USEPA 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 USEPA 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. USEPA 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 groundwater.
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 groundwater, 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.
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 USEPA 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-Contact Measurement of Exposure:
Estimating exposure by measuring concentrations over time (while the exposure is
taking place) at or near the place where it is occurring.
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 USEPA programs and can involve
cooperative efforts with such agencies as the Departments of Agriculture and
Energy. 2. USEPA has initiated a number of voluntary programs in which
industrial, or commercial or "partners" join with USEPA in promoting activities
that conserve energy, conserve and protect water supply, reduce emissions or
find ways of utilizing them as energy resources, and reduce the waste stream.
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.
Portal-of-Entry Effect:
A local effect produced in the tissue or organ of first contact between a
toxicant and the biological system.
Polonium:
A radioactive element that occurs in pitchblende and other uranium-containing
ores.
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.
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, USEPA 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.
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.
Pre-Consumer Materials/Waste:
Materials generated in manufacturing and converting processes such as
manufacturing scrap and trimmings and cuttings. Includes print overruns, over
issue publications, and obsolete inventories.
Pre-Harvest Interval:
The time between the last pesticide application and harvest of the treated
crops.
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,
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.
Pressure, Total:
In flowing air, the sum of the static and velocity pressures.
Pressure, Velocity:
In flowing air, the pressure due to velocity and density of air.
Pretreatment:
Processes used to reduce, eliminate, or alter the nature of wastewater
pollutants from non-domestic sources before they are discharged into publicly
owned treatment works (POTWs).
Prevalent Level Samples:
Air samples taken under normal conditions (also known as ambient background
samples).
Prevalent Levels:
Levels of airborne contaminant occurring under normal conditions.
Prevention of Significant Deterioration (PSD):
USEPA program in which state and/or federal permits are required in order to
restrict emissions from new or modified sources in places where air quality
already meets or exceeds primary and secondary ambient air quality standards.
Primacy:
Having the primary responsibility for administering and enforcing regulations.
Primary Drinking Water Regulation:
Applies to public water systems and specifies a contaminant level, which, in the
judgment of the USEPA Administrator, will not adversely affect human health.
Primary Treatment:
First stage of wastewater treatment in which solids are removed by screening and
settling.
Primary Waste Treatment:
First steps in wastewater treatment; screens and sedimentation tanks are used to
remove most materials that float or will settle. Primary treatment removes about
30 percent of carbonaceous biochemical oxygen demand from domestic sewage.
Principal Organic Hazardous Constituents (POHCs):
Hazardous compounds monitored during an incinerator's trial burn, selected for
high concentration in the waste feed and difficulty of combustion.
Prions:
Microscopic particles made of protein that can cause disease.
Prior Appropriation:
A doctrine of water law that allocates the rights to use water on a first-come,
first-served basis.
Probability of Detection :
The likelihood, expressed as a percentage, that a test method will correctly
identify a leaking tank.
Process Variable:
A physical or chemical quantity which is usually measured and controlled in the
operation of a water treatment plant or industrial plant.
Process Verification:
Verifying that process raw materials, water usage, waste treatment processes,
production rate and other facts relative to quantity and quality of pollutants
contained in discharges are substantially described in the permit application
and the issued permit.
Process Wastewater:
Any water that comes into contact with any raw material, product, byproduct, or
waste.
Process Weight:
Total weight of all materials, including fuel, used in a manufacturing process;
used to calculate the allowable particulate emission rate.
Producers:
Plants that perform photosynthesis and provide food to consumers.
Product Level:
The level of a product in a storage tank.
Product Water:
Water that has passed through a water treatment plant and is ready to be
delivered to consumers.
Products of Incomplete Combustion (PICs):
Organic compounds formed by combustion. Usually generated in small amounts and
sometimes toxic, PICs are heat-altered versions of the original material fed
into the incinerator (e.g. charcoal is a P.I.C. from burning wood).
Propellant:
Liquid in a self-pressurized pesticide product that expels the active ingredient
from its container.
Proportionate Mortality Ratio (PMR):
The number of deaths from a specific cause in a specific period of time per 100
deaths from all causes in the same time period.
Proposed Plan:
A plan for a site cleanup that is available to the public for comment.
Protocol:
A series of formal steps for conducting a test.
Protoplast:
A membrane-bound cell from which the outer wall has been partially or completely
removed. The term often is applied to plant cells.
Protozoa:
One-celled animals that are larger and more complex than bacteria. May cause
disease.
Public Comment Period:
The time allowed for the public to express its views and concerns regarding an
action by USEPA (e.g. a Federal Register Notice of proposed rule-making, a
public notice of a draft permit, or a Notice of Intent to Deny).
Public Hearing:
A formal meeting wherein USEPA officials hear the public's views and concerns
about an USEPA action or proposal. USEPA is required to consider such comments
when evaluating its actions. Public hearings must be held upon request during
the public comment period.
Public Notice:
1. Notification by USEPA informing the public of Agency actions such as the
issuance of a draft permit or scheduling of a hearing. USEPA is required to
ensure proper public notice, including publication in newspapers and broadcast
over radio and television stations. 2. In the safe drinking water program, water
suppliers are required to publish and broadcast notices when pollution problems
are discovered.
Public Water System:
A system that provides piped water for human consumption to at least 15 service
connections or regularly serves 25 individuals.
Publicly Owned Treatment Works (POTWs):
A waste-treatment works owned by a state, unit of local government, or Indian
tribe, usually designed to treat domestic wastewaters.
Pumping Station:
Mechanical device installed in sewer or water system or other liquid-carrying
pipelines to move the liquids to a higher level.
Pumping Test:
A test conducted to determine aquifer or well characteristics.
Purging:
Removing stagnant air or water from sampling zone or equipment prior to sample
collection.
Putrefaction:
Biological decomposition of organic matter; associated with anaerobic
conditions.
Putrescible:
Able to rot quickly enough to cause odors and attract flies.
Pyrolysis:
Decomposition of a chemical by extreme heat.
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