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

Household Waste (Domestic Waste)
Solid waste, composed of garbage and rubbish, which normally originates in a private home or apartment house. Domestic waste may contain a significant amount of toxic or hazardous waste.

Human Equivalent Dose
A dose which, when administered to humans, produces an effect equal to that produced by a dose in animals.

Human Exposure Evaluation
Describing the nature and size of the population exposed to a substance and the magnitude and duration of their exposure.

Human Health Risk
The likelihood that a given exposure or series of exposures may have damaged or will damage the health of individuals.

Hydraulic Conductivity
The rate at which water can move through a permeable medium. (i.e. the coefficient of permeability.)

Hydraulic Gradient
In general, the direction of groundwater flow due to changes in the depth of the water table.

Hydrocarbons (HC)
Chemical compounds that consist entirely of carbon and hydrogen.

Hydrogen Sulfide (H2S)
Gas emitted during organic decomposition. Also a by-product of oil refining and burning. Smells like rotten eggs and, in heavy concentration, can kill or cause illness.

Hydrogeological Cycle
The natural process recycling water from the atmosphere down to (and through) the earth and back to the atmosphere again.

Hydrogeology
The geology of ground water, with particular emphasis on the chemistry and movement of water.

Hydrologic Cycle
Movement or exchange of water between the atmosphere and earth.

Hydrology
The science dealing with the properties, distribution, and circulation of water.

Hydrolysis
The decomposition of organic compounds by interaction with water.

Hydronic
A ventilation system using heated or cooled water pumped through a building.

Hydrophilic
Having a strong affinity for water.

Hydrophobic
Having a strong aversion for water.

Hydropneumatic
A water system, usually small, in which a water pump is automatically controlled by the pressure in a compressed air tank.

Hypersensitivity Diseases
Diseases characterized by allergic responses to pollutants; diseases most clearly associated with indoor air quality are asthma, rhinitis, and pneumonic hypersensitivity.

Hypolimnion
Bottom waters of a thermally stratified lake. The hypolimnion of a eutrophic lake is usually low or lacking in oxygen.

Hypoxia-Hypoxic Waters
Waters with dissolved oxygen concentrations of less than 2 ppm, the level generally accepted as the minimum required for most marine life to survive and reproduce.

Ignitable
Capable of burning or causing a fire.

IM240
A high-tech, transient dynamometer automobile emissions test that takes up to 240 seconds.

Imhoff Cone
A clear, cone-shaped container used to measure the volume of settleable solids in a specific volume of water.

Imminent Hazard
One that would likely result in unreasonable adverse effects on humans or the environment or risk unreasonable hazard to an endangered species during the time required for a pesticide registration cancellation proceeding.

Imminent Threat
A high probability that exposure is occurring.

Immiscibility
The inability of two or more substances or liquids to readily dissolve into one another, such as soil and water. Immiscibility The inability of two or more substances or liquids to readily dissolve into one another, such as soil and water.

Impermeable
Not easily penetrated. The property of a material or soil that does not allow, or allows only with great difficulty, the movement or passage of water.

Imports
Municipal solid waste and recyclables that have been transported to a state or locality for processing or final disposition (but that did not originate in that state or locality).

Impoundment
A body of water or sludge confined by a dam, dike, floodgate, or other barrier.

In Situ
In its original place; unmoved unexcavated; remaining at the site or in the subsurface.

In Vitro
Testing or action outside an organism (e.g. inside a test tube or culture dish.)

In Vivo
Testing or action inside an organism.

In-Line Filtration
Pre-treattment method in which chemicals are mixed by the flowing water; commonly used in pressure filtration installations. Eliminates need for flocculation and sedimentation.

In-Situ Flushing
Introduction of large volumes of water, at times supplemented with cleaning compounds, into soil, waste, or ground water to flush hazardous contaminants from a site.

In-Situ Oxidation
Technology that oxidizes contaminants dissolved in ground water, converting them into insoluble compounds.

In-Situ Stripping
Treatment system that removes or 'strips' volatile organic compounds from contaminated ground or surface water by forcing an airstream through the water and causing the compounds to evaporate.

In-Situ Vitrification
Technology that treats contaminated soil in place at extremely high temperatures, at or more than 3000 degrees Fahrenheit.

Incident Command Post
A facility located at a safe distance from an emergency site, where the incident commander, key staff, and technical representatives can make decisions and deploy emergency manpower and equipment.

Incident Command System (ICS)
The organizational arrangement wherein one person, normally the Fire Chief of the impacted district, is in charge of an integrated, comprehensive emergency response organization and the emergency incident site, backed by an Emergency Operations Center staff with resources, information, and advice.

Incineration
A treatment technology involving destruction of waste by controlled burning at high temperatures; e.g., burning sludge to remove the water and reduce the remaining residues to a safe, non-burnable ash that can be disposed of safely on land, in some waters, or in underground locations.

Incineration at Sea
Disposal of waste by burning at sea on specially-designed incinerator ships.

Incinerator
A furnace for burning waste under controlled conditions.

Incompatible Waste
A waste unsuitable for mixing with another waste or material because it may react to form a hazard.

Indemnification
In the pesticide program, legal requirement that EPA pay certain end-users, dealers, and distributors for the cost of stock on hand at the time a pesticide registration is suspended.

Indicator
In biology, any biological entity or processes, or community whose characteristics show the presence of specific environmental conditions. 2. In chemistry, a substance that shows a visible change, usually of color, at a desired point in a chemical reaction. 3.A device that indicates the result of a measurement; e.g. a pressure gauge or a moveable scale.

Indirect Discharge
Introduction of pollutants from a non-domestic source into a publicly owned waste-treatment system. Indirect dischargers can be commercial or industrial facilities whose wastes enter local sewers.

Indirect Source
Any facility or building, property, road or parking area that attracts motor vehicle traffic and, indirectly, causes pollution.

Indoor Air
The breathable air inside a habitable structure or conveyance.

Indoor Air Pollution
Chemical, physical, or biological contaminants in indoor air.

Indoor Climate
Temperature, humidity, lighting, air flow and noise levels in a habitable structure or conveyance. Indoor climate can affect indoor air pollution.

Industrial Pollution Prevention
Combination of industrial source reduction and toxic chemical use substitution.

Industrial Process Waste
Residues produced during manufacturing operations.

Industrial Sludge
Semi-liquid residue or slurry remaining from treatment of industrial water and wastewater.

Industrial Source Reduction
Practices that reduce the amount of any hazardous substance, pollutant, or contaminant entering any waste stream or otherwise released into the environment. Also reduces the threat to public health and the environment associated with such releases. Term includes equipment or technology modifications, substitution of raw materials, and improvements in housekeeping, maintenance, training or inventory control.

Industrial Waste
Unwanted materials from an industrial operation; may be liquid, sludge, solid, or hazardous waste.

Inert Ingredient
Pesticide components such as solvents, carriers, dispersants, and surfactants that are not active against target pests. Not all inert ingredients are innocuous.

Inertial Separator
A device that uses centrifugal force to separate waste particles.

Infectious Agent
Any organism, such as a pathogenic virus, parasite, or or bacterium, that is capable of invading body tissues, multiplying, and causing disease.

Infectious Waste
Hazardous waste capable of causing infections in humans, including contaminated animal waste; human blood and blood products; isolation waste, pathological waste; and discarded sharps (needles, scalpels or broken medical instruments).

Infiltration
1. The penetration of water through the ground surface into sub-surface soil or the penetration of water from the soil into sewer or other pipes through defective joints, connections, or manhole walls. 2. The technique of applying large volumes of waste water to land to penetrate the surface and percolate through the underlying soil. (See percolation.)

Infiltration Gallery
A sub-surface groundwater collection system, typically shallow in depth, constructed with open-jointed or perforated pipes that discharge collected water into a watertight chamber from which the water is pumped to treatment facilities and into the distribution system. Usually located close to streams or ponds.

Infiltration Rate
The quantity of water that can enter the soil in a specified time interval.

Inflow
Entry of extraneous rain water into a sewer system from sources other than infiltration, such as basement drains, manholes, storm drains, and street washing.

Influent
Water, wastewater, or other liquid flowing into a reservoir, basin, or treatment plant.

Inhalable Particles
All dust capable of entering the human respiratory tract.

Initial Compliance Period (Water)
The first full three-year compliance period which begins at least 18 months after promulgation.

Injection Well
A well into which fluids are injected for purposes such as waste disposal, improving the recovery of crude oil, or solution mining.

Injection Zone
A geological formation receiving fluids through a well.

Innovative Technologies
New or inventive methods to treat effectively hazardous waste and reduce risks to human health and the environment.

Innovative Treatment Technologies
Technologies whose routine use is inhibited by lack of data on performance and cost. (See Established treatment technologies.)

Inoculum
1. Bacteria or fungi injected into compost to start biological action. 2. A medium containing organisms, usually bacteria or a virus, that is introduced into cultures or living organisms.

Inorganic Chemicals
Chemical substances of mineral origin, not of basically carbon structure.

Insecticide
A pesticide compound specifically used to kill or prevent the growth of insects.

Inspection and Maintenance (I-M)
1. Activities to ensure that vehicles' emission controls work properly. 2. Also applies to wastewater treatment plants and other anti-pollution facilities and processes.

Institutional Waste
Waste generated at institutions such as schools, libraries, hospitals, prisons, etc.

Instream Use
Water use taking place within a stream channel; e.g., hydro-electric power generation, navigation, water quality improvement, fish propagation, recreation.

Integrated Exposure Assessment
Cumulative summation (over time) of the magnitude of exposure to a toxic chemical in all media.

Integrated Pest Management (IPM)
A mixture of chemical and other, non-pesticide, methods to control pests.

Integrated Waste Management
Using a variety of practices to handle municipal solid waste; can include source reduction, recycling, incineration, and landfilling.

Interceptor Sewers
Large sewer lines that, in a combined system, control the flow of sewage to the treatment plant. In a storm, they allow some of the sewage to flow directly into a receiving stream, thus keeping it from overflowing onto the streets. Also used in separate systems to collect the flows from main and trunk sewers and carry them to treatment points.

Interface
The common boundary between two substances such as a water and a solid, water and a gas, or two liquids such as water and oil.

Interfacial Tension
The strength of the film separating two immiscible fluids (e.g. oil and water) measured in dynes per, or millidynes per centimeter.

Interim (Permit) Status
Period during which treatment, storage and disposal facilities coming under RCRA in 1980 are temporarily permitted to operate while awaiting a permanent permit. Permits issued under these circumstances are usually called 'Part A' or 'Part B' permits.

Internal Dose
In exposure assessment, the amount of a substance penetrating the absorption barriers (e.g. skin, lung tissue, gastrointestinal tract) of an organism through either physical or biological processes. (See absorbed dose)

Interstate Carrier Water Supply
A source of water for drinking and sanitary use on planes, buses, trains, and ships operating in more than one state. These sources are federally regulated.

Interstate Commerce Clause
A clause of the U.S. Constitution which reserves to the federal government the right to regulate the conduct of business across state lines. Under this clause, for example, the U.S. Supreme Court has ruled that states may not inequitably restrict the disposal of out-of-state wastes in their jurisdictions.

Interstate Waters
Waters that flow across or form part of state or international boundaries; e.g. the Great Lakes, the Mississippi River, or coastal waters.

Interstitial Monitoring
The continuous surveillance of the space between the walls of an underground storage tank.

Intrastate Product
Pesticide products once registered by states for sale and use only in the state. All intrastate products have been converted to full federal registration or canceled.

Inventory (TSCA)
Inventory of chemicals produced pursuant to Section 8 (b) of the Toxic Substances Control Act.

Inversion
A layer of warm air that prevents the rise of cooling air and traps pollutants beneath it; can cause an air pollution episode.

Ion
An electrically charged atom or group of atoms.

Ion Exchange Treatment
A common water-softening method often found on a large scale at water purification plants that remove some organics and radium by adding calcium oxide or calcium hydroxide to increase the pH to a level where the metals will precipitate out.

Ionization Chamber
A device that measures the intensity of ionizing radiation.

Ionizing Radiation
Radiation that can strip electrons from atoms; e.g. alpha, beta, and gamma radiation.

IRIS
EPA's Integrated Risk Information System, an electronic data base containing the Agency's latest descriptive and quantitative regulatory information on chemical constituents.

Irradiated Food
Food subject to brief radioactivity, usually gamma rays, to kill insects, bacteria, and mold, and to permit storage without refrigeration.

Irradiation
Exposure to radiation of wavelengths shorter than those of visible light (gamma, x-ray, or ultra- violet), for medical purposes, to sterilize milk or other foodstuffs, or to induce polymerization of monomers or vulcanization of rubber.

Irreversible Effect
Effect characterized by the inability of the body to partially or fully repair injury caused by a toxic agent.

Irrigation
Applying water or wastewater to land areas to supply the water and nutrient needs of plants.