Laboratory Terms

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

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Ocean Discharge Waiver: A variance from Clean Water Act requirements for discharges into marine waters.
Odor Threshold: The minimum odor of a water or air sample that can just be detected after suc...
OECD Guidelines: Testing guidelines prepared by the Organization of Economic and Cooperative D...
Off-Site Facility: A hazardous waste treatment, storage or disposal area that is located away fr...
Office Paper: High grade papers such as copier paper, computer printout, and stationary alm...
Offsets: A concept whereby emissions from proposed new or modified stationary sources ...
Offstream Use: Water withdrawn from surface or groundwater sources for use at another place.
Oil and Gas Waste: Gas and oil drilling muds, oil production brines, and other waste associated ...
Oil Desulfurization: Widely used precombustion method for reducing sulfur dioxide emissions from o...
Oil Fingerprinting: A method that identifies sources of oil and allows spills to be traced to the...
Oil Spill: An accidental or intentional discharge of oil which reaches bodies of water. ...
Oligotrophic Lakes: Deep clear lakes with few nutrients, little organic matter and a high dissolv...
On-Scene Coordinator OSC: The predesignated EPA, Coast Guard, or Department of Defense official who coo...
On-Site Facility: A hazardous waste treatment, storage or disposal area that is located on the ...
Onboard Controls: Devices placed on vehicles to capture gasoline vapor during refueling and rou...
Onconogenicity: The capacity to induce cancer.
One-hit Model: A mathematical model based on the biological theory that a single "hit" of so...
Opacity: The amount of light obscured by particulate pollution in the air; clear windo...
Open Burning: Uncontrolled fires in an open dump.
Open Dump: An uncovered site used for disposal of waste without environmental controls.
Operable Unit: Term for each of a number of separate activities undertaken as part of a Supe...
Operating Conditions: Conditions specified in a RCRA permit that dictate how an incinerator must op...
Operation and Maintenance: 1. Activities conducted after a Superfund site action is completed to ensure ...
Operator Certification: Certification of operators of community and nontransient noncommunity water s...
Optimal Corrosion Control Treatment: An erosion control treatment that minimizes the lead and copper concentration...
Oral Toxicity: Ability of a pesticide to cause injury when ingested.
Organic: 1. Referring to or derived from living organisms. 2. In chemistry, any compou...
Organic Chemicals: Naturally occuring (animal or plant-produced or synthetic) substances contain...
Organic Matter: Carbonaceous waste contained in plant or animal matter and originating from d...
Organism: Any form of animal or plant life.
Organophosphates: Pesticides that contain phosphorus; short-lived, but some can be toxic when f...
Organophyllic: A substance that easily combines with organic compounds.
Organotins: Chemical compounds used in anti-foulant paints to protect the hulls of boats ...
Original AHERA Inspection: Examination of school buildings arranged by Local Education Agencies to ident...
Original Generation Point: Where regulated medical or other material first becomes waste.
Osmosis: The passage of a liquid from a weak solution to a more concentrated solution ...
Other Ferrous Metals: Recyclable metals from strapping, furniture, and metal found in tires and con...
Other Glass: Recyclable glass from furniture, appliances, and consumer electronics. Does n...
Other Nonferrous Metals: Recyclable nonferrous metals such as lead, copper, and zinc from appliances, ...
Other Paper: For Recyclable paper from books, third-class mail, commercial printing, paper...
Other Plastics: Recyclable plastic from appliances, eating utensils, plates, containers, toys...
Other Solid Waste: Recyclable nonhazardous solid wastes, other than municipal solid waste, cover...
Other Wood: Recyclable wood from furniture, consumer electronics cabinets, and other nonp...
Outdoor Air Supply: Air brought into a building from outside.
Outfall: The place where effluent is discharged into receiving waters.
Overburden: Rock and soil cleared away before mining.
Overdraft: The pumping of water from a groundwater basin or aquifer in excess of the sup...
Overfire Air: Air forced into the top of an incinerator or boiler to fan the flames.
Overflow Rate: One of the guidelines for design of the settling tanks and clarifers in a tre...
Overland Flow: A land application technique that cleanses waste water by allowing it to flow...
Oversized Regulated Medical Waste: Medical waste that is too large for plastic bags or standard containers.
Overturn: One complete cycle of top to bottom mixing of previously stratified water mas...
Oxidant: A collective term for some of the primary constituents of photochemical smog.
Oxidation: The chemical addition of oxygen to break down pollutants or organizac waste; ...
Oxidation Pond: A man-made (anthropogenic) body of water in which waste is consumed by bacter...
Oxidation-Reduction Potential: The electric potential required to transfer electrons from one compound or el...
Oxygenated Fuels: Gasoline which has been blended with alcohols or ethers that contain oxygen i...
Oxygenated Solvent: An organic solvent containing oxygen as part of the molecular structure. Alco...
Ozonation: Application of ozone to water for disinfection or for taste and odor control....
Ozone Depletion: Destruction of the stratospheric ozone layer which shields the earth from ult...
Ozone Hole: A thinning break in the stratospheric ozone layer. Designation of amount of s...
Ozone Layer: The protective layer in the atmosphere, about 15 miles above the ground, that...
Ozone O3: Found in two layers of the atmosphere, the stratosphere and the troposphere. ...

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