Laboratory Terms

A glossary of science, chemistry, environmental and laboratory terms.

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Packaging: The assembly of one or more containers and any other components necessary to ...
Packed Bed Scrubber: An air pollution control device in which emissions pass through alkaline wate...
Packed Tower: A pollution control device that forces dirty air through a tower packed with ...
Packer: An inflatable gland, or balloon, used to create a temporary seal in a borehol...
Palatable Water: Water, at a desirable temperature, that is free from objectionable tastes, od...
Pandemic: A widespread epidemic throughout an area, nation or the world.
Paper: In the recycling business, refers to products and materials, including newspa...
Paper Processor: Intermediate facility where recovered paper or plastic products and materials...
Parameter: A variable, measurable property whose value is a determinant of the character...
Paraquat: A standard herbicide used to kill various types of crops, including marijuana...
Parshall Flume: Device used to measure the flow of water in an open channel.
Participation Rate: Portion of population participating in a recycling program.
Particle Count: Results of a microscopic examination of treated water with a special "particl...
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, ...
Partition Coefficient: Measure of the sorption phenomenon, whereby a pesticide is divided between th...
Parts Per Billion ppb: Units commonly used to express contamination ratios, as in establishing the m...
Passive Smoking: Inhalation of others' tobacco smoke.
Passive Treatment Walls: Technology in which a chemical reaction takes place when contaminated ground ...
Pathogens: Microorganisms (e.g., bacteria, viruses, or parasites) that can cause disease...
Pathway: The physical course a chemical or pollutant takes from its source to the expo...
Pay-As-You-Throw: Systems under which residents pay for municipal waste management and disposal...
PCB Congeners: Chlorine-substituted biphenyl compounds. PCB stands for polychlorinated biphe...
Peak Electricity Demand: The maximum electricity used to meet the cooling load of a building or buildi...
Peak Levels: Levels of airborne pollutant contaminants much higher than average or occurri...
Percent Saturation: The amount of a substance that is dissolved in a solution compared to the amo...
Perched Water: Zone of unpressurized water held above the water table by impermeable rock or...
Perchlorates: Perchlorates are the salts derived from perchloric acid (HClO4). They occur b...
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...
Performance Bond: Cash or securities deposited before a landfill operating permit is issued, wh...
Performance Data: Information collected, during a trial burn, on concentrations of designated o...
Performance Standards: 1. Regulatory requirements limiting the concentrations of designated organic ...
Periphyton: Microscopic underwater plants and animals that are firmly attached to solid s...
Permeability: The rate at which liquids pass through soil or other materials in a specified...
Permissible Dose: The dose of a chemical that may be received by an individual without the expe...
Permissible Exposure Limit: Also referred to as PEL, federal limits for workplace exposure to contaminant...
Permit: An authorization, license, or equivalent control document issued by EPA or an...
Persistence: Refers to the length of time a compound stays in the environment, once introd...
Persistent Pesticides: Pesticides that do not break down chemically or break down very slowly and re...
Personal Air Samples: Air samples taken with a pump that is directly attached to the worker with th...
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 ...
Pest: An insect, rodent, nematode, fungus, weed or other form of terrestrial or aqu...
Pest Control Operator: Person or company that applies pesticides as a business (e.g. exterminator); ...
Pesticide: Substances or mixture there of intended for preventing, destroying, repelling...
Pesticide Regulation Notice: Formal notice to pesticide registrants about important changes in regulatory ...
Pesticide Tolerance: The amount of pesticide residue allowed by law to remain in or on a harvested...
PETE: Polyethylene Terepthalate. Thermoplastic material used in plastic soft drink ...
Petroleum: Crude oil or any fraction thereof that is liquid under normal conditions of t...
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; ma...
Pharmacokinetics: The study of the way that drugs move through the body after they are swallowe...
Phenolphthalein Alkalinity: The alkalinity in a water sample measured by the amount of standard acid need...
Phenols: Organic compounds that are byproducts of petroleum refining, tanning, and tex...
Phosphates: Certain chemical compounds containing phosphorus.
Phosphogypsum Piles Stacks: Principal byproduct generated in production of phosphoric acid from phosphate...
Phosphorus: An essential chemical food element that can contribute to the eutrophication ...
Phosphorus Plants: Facilities using electric furnaces to produce elemental phosphorous for comme...
Photochemical Oxidants: Air pollutants formed by the action of sunlight on oxides of nitrogen and hyd...
Photochemical Smog: Air pollution caused by chemical reactions of various pollutants emitted from...
Photosynthesis: The manufacture by plants of carbohydrates and oxygen from carbon dioxide med...
Physical and Chemical Treatment: Processes generally used in large-scale wastewater treatment facilities. Phys...
Phytoplankton: That portion of the plankton community comprised of tiny plants; e.g. algae, ...
Phytoremediation: Low-cost remediation option for sites with widely dispersed contamination at ...
Phytotoxic: Harmful to plants.
Phytotreatment: The cultivation of specialized plants that absorb specific contaminants from ...
Picocuries Per Liter: A unit of measure for levels of radon gas; becquerels per cubic meter is metr...
Piezometer: A nonpumping well, generally of small diameter, for measuring the elevation o...
Pilot Tests: Testing a cleanup technology under actual site conditions to identify potenti...
Plankton: Tiny plants and animals that live in water.
Plasma Arc Reactors: devices that use an electric arc to thermally decompose organic and inorganic...
Plasmid: A circular piece of DNA that exists apart from the chromosome and replicates ...
Plastics: Non-metallic chemoreactive compounds molded into rigid or pliable constructio...
Plate Tower Scrubber: An air pollution control device that neutralizes hydrogen chloride gas by bub...
Plug Flow: Type of flow the occurs in tanks, basins, or reactors when a slug of water mo...
Plugging: Act or process of stopping the flow of water, oil, or gas into or out of a fo...
Plume: 1. A visible or measurable discharge of a contaminant from a given point of o...
Plutonium: A radioactive metallic element chemically similar to uranium.
PM-10: PM 10 is measure of particles in the atmosphere with a diameter of less than ...
Pneumoconiosis: Health conditions characterized by permanent deposition of substantial amount...
Point Source: A stationary location or fixed facility from which pollutants are discharged;...
Point-of-Contact Measurement of Exposure: Estimating exposure by measuring concentrations over time (while the exposure...
Point-of-Disinfectant Application: The point where disinfectant is applied and water downstream of that point is...
Point-of-Use Treatment Device: Treatment device applied to a single tap to reduce contaminants in the drinki...
Pollen: The fertilizing element of flowering plants; background air pollutant.
Pollutant: Generally, any substance introduced into the environment that adversely affec...
Pollutant Pathways: Avenues for distribution of pollutants. In most buildings, for example, HVAC ...
Pollutant Standard Index PSI: Indicator of one or more pollutants that may be used to inform the public abo...
Pollution: Generally, the presence of a substance in the environment that because of its...
Pollution Prevention: 1. Identifying areas, processes, and activities which create excessive waste ...
Polonium: A radioactive element that occurs in pitchblende and other uranium-containing...
Polychlorinated Biphenyls: A group of toxic, persistent chemicals used in electrical transformers and ca...
Polyelectrolytes: Synthetic chemicals that help solids to clump during sewage treatment.
Polyethylene Diffusion Bags PDB: Polyethylene Diffusion Bags are bags used to collect water samples for labora...
Polymer: A natural or synthetic chemical structure where two or more like molecules ar...
Polyvinyl Chloride PVC: A tough, environmentally indestructible plastic that releases hydrochloric ac...
Population: A group of interbreeding organisms occupying a particular space; the number o...
Population at Risk: A population subgroup that is more likely to be exposed to a chemical, or is ...
Porosity: Degree to which soil, gravel, sediment, or rock is permeated with pores or ca...
Portal-of-Entry Effect: A local effect produced in the tissue or organ of first contact between a tox...
Post-Chlorination: Addition of chlorine to plant effluent for disinfectant purposes after the ef...
Post-Closure: The time period following the shutdown of a waste management or manufacturing...
Post-Consumer Materials: Materials or finished products that have served their intended use and have b...
Post-Consumer Recycling: Use of materials generated from residential and consumer waste for new or sim...
Potable Water: Water that is safe for drinking and cooking.
Potential Dose: The amount of a compound contained in material swallowed, breathed, or applie...
Potentially Responsible Party PRP: Any individual or company--including owners, operators, transporters or gener...
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: Materials generated in manufacturing and converting processes such as manufac...
Pre-Harvest Interval: The time between the last pesticide application and harvest of the treated cr...
Precautionary Principle: When information about potential risks is incomplete, basing decisions about ...
Prechlorination: The addition of chlorine at the headworks of a treatment plant prior to other...
Precipitate: A substance separated from a solution or suspension by chemical or physical c...
Precipitation: Removal of hazardous solids from liquid waste to permit safe disposal; remova...
Precipitator: Pollution control device that collects particles from an air stream.
Precursor: In photochemistry, a compound antecedent to a pollutant. For example, volatil...
Preliminary Assessment: The process of collecting and reviewing available information about a known o...
Prescriptive: Water rights which are acquired by diverting water and putting it to use in a...
Pressed Wood Products: Materials used in building and furniture construction that are made from wood...
Pressure Sewers: A system of pipes in which water, wastewater, or other liquid is pumped to a ...
Pretreatment: Processes used to reduce, eliminate, or alter the nature of wastewater pollut...
Prevalent Level Samples: Air samples taken under normal conditions (also known as ambient background s...
Prevalent Levels: Levels of airborne contaminant occurring under normal conditions.
Prevention of Significant Deterioration PSD: EPA program in which state and/or federal permits are required in order to re...
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 ...
Primary Effect: An effect where the stressor acts directly on the ecological component of int...
Primary Standards: National ambient air quality standards designed to protect human health with ...
Primary Treatment: First stage of wastewater treatment in which solids are removed by screening ...
Primary Waste Treatment: First steps in wastewater treatment; screens and sedimentation tanks are used...
Principal Organic Hazardous Constituents: Hazardous compounds monitored during an incinerator's trial burn, selected fo...
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-com...
Probability of Detection: The likelihood, expressed as a percentage, that a test method will correctly ...
Process Variable: A physical or chemical quantity which is usually measured and controlled in t...
Process Verification: Verifying that process raw materials, water usage, waste treatment processes,...
Process Wastewater: Any water that comes into contact with any raw material, product, byproduct, ...
Process Weight: Total weight of all materials, including fuel, used in a manufacturing proces...
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 deli...
Products of Incomplete Combustion PICs: Organic compounds formed by combustion. Usually generated in small amounts an...
Project XL: An EPA initiative to give states and the regulated community the flexibility ...
Propellant: Liquid in a self-pressurized pesticide product that expels the active ingredi...
Proportionate Mortality Ratio PMR: The number of deaths from a specific cause in a specific period of time per 1...
Proposed Plan: A plan for a site cleanup that is available to the public for comment.
Proteins: Complex nitrogenous organic compounds of high molecular weight made of amino ...
Protocol: A series of formal steps for conducting a test.
Protoplast: A membrane-bound cell from which the outer wall has been partially or complet...
Protozoa: One-celled animals that are larger and more complex than bacteria. May cause ...
Public Comment Period: The time allowed for the public to express its views and concerns regarding a...
Public Health Approach: Regulatory and voluntary focus on effective and feasible risk management acti...
Public Health Context: The incidence, prevalence, and severity of diseases in communities or populat...
Public Hearing: A formal meeting wherein EPA officials hear the public's views and concerns a...
Public Notice: 1. Notification by EPA informing the public of Agency actions such as the iss...
Public Water System: A system that provides piped water for human consumption to at least 15 servi...
Publicly Owned Treatment Works POTWs: A waste-treatment works owned by a state, unit of local government, or Indian...
Pumping Station: Mechanical device installed in sewer or water system or other liquid-carrying...
Pumping Test: A test conducted to determine aquifer or well characteristics.
Purging: Removing stagnant air or water from sampling zone or equipment prior to sampl...

Analytical testing dots

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