Environment terminology · MLC-0121

Environment terms: I (1,291)

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• Internal Scrubbing SystemWet scrubbing, wet injection, or caustic injection control device that treats (in-situ) the catalytic...
• Internal Standard1. A pure analyte (s) or labeled compound added to a sample, extract, or standard solution in known amount(s)...
• Internal Standard Quantitation1. A means of determining the concentration of a naturally occurring (native) compound or labeled compound by...
• Internal SubunitSubunit that is covalently linked to at least two other subunits. Internal subunits of polymer molecules are...
• Internal ValidityThe extent to which the causes of an effect are established by an inquiry.
• Internal Validity ThreatFactors other than program participation that may affect the results or findings.
• Internal WaveA wave that propagates along a density surface within the water column, below the water’s surface.
• International Affairs & CommerceInternational Affairs and Commerce involves the non-military activities that promote U.S. policies and...
• INTERNATIONAL AGREEMENTA written agreement between a Federal agency and a foreign government under which work will be conducted for...
• International AgreementsAgreements under which work will be conducted for a foreign government or involving international work or...
• International CodeModel codes published by the International Code Council (ICC) to combine all four model building codes into...
• International CodesModel codes published by the International Code Council (ICC) to combine all four model building codes into...
• International Development & Humanitarian AidInternational Development and Humanitarian Aid refers to those activities related to the implementation of...
• International Environmental Cooperation & AgreementsActivities associated with Agency membership in international environmental organizations, development of...
• International Environmental Technical AssistanceActivities to support development and application of technical assistance for international environmental...
• International Joint CommissionCommission established by the Boundary Waters Treaty of 1909, consisting of representatives from both the...
• International Organization for Standardization 9001-Registered FacilityManufacturing facility that is either:(1) An International Organization for Standardization (ISO)...
• International Organization for Standardization Method 10312Ambient air -- Determination of asbestos fibres - Direct transfer transmission electron microscopy method.
• International Organization for Standardization StandardsISO standards are developed by an international body in order to establish requirements, specifications...
• International ShipmentTransportation of hazardous waste into or out of the jurisdiction of the United States.
• International Source EmissionEmission not originating in the United States.
• International Standard Serials NumberISSN is a unique eight digit code that identifies periodicals.
• INTERNATIONAL STANDARDIZATION ORGANIZATIONA standards-setting organization with representatives from many nations. See also AMERICAN NATIONAL STANDARDS...
• Internet1. The Internet is a worldwide system of linked computer networks. It provides billions of individuals...
• Internet Protocol addressThis definition is based on Internet Protocol Version 4. See Internet Protocol Version 6 (IPv6) for a...
• Internet Protocol StackPart of the behind the scenes software that allows a computer to connect and communicate through the...
• InteroperabilityThe capability to communicate, execute programs, or transfer data among various functional units in a manner...
• Interoperability LevelThe six levels necessary for true interoperability
• Interpenetrating NetworkA polymer which has two or more networks which cannot be separated without breaking bonds, but which are not...
• Interpenetrating subsamplesIf a sample is partitioned into subsamples, each of which closely reflects the structure of the full design...
• Interphase1. The interval between two successive cell divisions during which the chromosomes are not individually...
• Interpolation1. A method to determine intermediate values from surrounding known values.
• Interpretation1. The evaluation of the results of the inventory analysis and impact assessment to reduce environmental...
• Interpretive Guidance DocumentsIn general, policy, guidance, and interpretive documents describe how the Agency intends to exercise its...
• Interquartile Range1. A measure of spread; a statistic used with ordinal, interval, and ratio variables.
• Interrater ReliabilityThe extent to which two different researchers obtain the same result when using the same instrument to...
• Interregional Research Project No. 4Funded by the U.S. Department of Agriculture; IR-4 generates data to support minor use registrations, and...
• Interrupted Time Series DesignThe interrupted time series design involves repeated measurement of an indicator (e.g., reported crime) over...
• Interrupted Times Series DesignThe interrupted time series design involves repeated measurement of an indicator (e.g., reported crime) over...
• Interruptible DemandDemands that, by contract, can be interrupted if the supplying system lacks capacity.
• Intersatellite LinkA message transmission circuit between two communication satellites, as opposed to a circuit between a single...
• IntersexAn animal (usually a fish) that displays both male and female characteristics. Intersex in fish has been...
• Interspecies Dose Conversion1. The process of extrapolating from animal doses to human equivalent doses.
• Interspecies Extrapolation ModelModel used to extrapolate from results observed in laboratory animals to humans.
• Inter-Species RelationshipInteractions between creatures of different species, such as adoption and care-taking as well as parasitism .
• Interspecific CompetitionCompetition between individuals of different species (Ricklefs 1979:873).
• Interstate Agency1. An agency of two or more States established by or under an agreement or compact approved by the Congress...
• Interstate CarrierAny vehicle or transport which conveys passengers in interstate commerce.
• Interstate Carrier Water SupplyA source of water for drinking and sanitary use on planes, buses, trains, and ships operating in more than...
• interstate commerce1. A clause of the United States Constitution which reserves to the federal government the right to regulate...
• Interstate Commerce ClauseA clause of the U.S. Constitution which reserves to the federal government the right to regulate the conduct...
• Interstate WatersWaters that flow across or form part of state or international boundaries; e.g. the Great Lakes, the...
• Interstice(in-TUR-stuhz) A very small open space in a rock or granular material.
• interstitialThe matrix of air or liquid between sediment particles.
• Interstitial Lung DiseasesHeterogeneous group of noninfectious, nonmalignant disorders of the lower respiratory tract, affecting...
• Interstitial MonitoringThe continuous surveillance of the space between the walls of an underground storage tank.
• Interstitial PneumoniaA chronic form of pneumonia with increase of the interstitial tissue and decrease of the proper lung tissue
• Interstitial SpaceThe matrix of air or liquid between sediment particles; pore space.
• Interstitial WaterWater contained in the interstices, which are the pore spaces or voids in soils and rocks, i.e., ground water.
• IntertidalThe area of shoreline between the high tide and low tide marks.
• Intertidal AreaArea of shoreline between the high tide and low tide marks.
• Inter-Tribal ConsortiaA coalition of two or more separate Indian tribes that join together for the purpose of applying for a grant...
• Intertribal Consortium1. Partnership between two or more Tribes that is authorized by the governing bodies of those Tribes to apply...
• Intertropical Convergence ZoneThe region where the northeasterly and southeasterly trade winds converge, forming an often continuous band...
• Interval EstimateGeneral term for an estimate of a population parameter that is a range of numerical values.
• Interval MeasureA quantitative measure with equal intervals between categories, but with no absolute zero.
• Interval Scale1. A measurement scale that measures quantitative differences between values of a variable, with equal...
• Interval transit timeThe time required for a compressional acoustic wave to travel a unit distance (t); transit time usually is...
• Interval VariableA quantitative variable that attributes of which are ordered and for which the numerical differences between...
• IntervenerPerson who files a motion to be made a party under § 209.15 or § 209.16, and whose motion is approved.
• Intervening VariableA variable that causally links other variables to each other. In a causal model, this intermediate variable...
• InterventionIncludes both physical procedures by which information or biospecimens are gathered (e.g., venipuncture) and...
• Interventional FluoroscopyA technique using x-rays to guide small instruments such as catheters through blood vessels or other pathways...
• InterviewInterviews involve face-to-face situations or telephone contacts in which the researcher orally solicits...
• Interviewer BiasThe influence of the interviewer on the interviewee. This may result from several factors, including the...
• InterviewsInterviews involve face-to-face situations or telephone contacts in which the researcher orally solicits...
• Interzonal air flowsTransport of air through doorways, ductwork, and service chaseways that interconnect rooms or zones within a...
• Intestinal DisordersA non-neoplastic or neoplastic disorder that affects the small or large intestine.
• Intestine1. The portion of the gastrointestinal tract between the stomach and the anus. It includes the small...
• Intolerant Animal SpeciesAn organism (or species) that is not adaptable to human alterations to its environment and thus declines in...
• Intracellular Communication InductionAny subcellular process that acts to positively regulate the catalytic activities that underlie intracellular...
• Intracellular Communication InhibitionAny subcellular process that acts to negatively regulate the catalytic activities that underlie intracellular...
• Intracellular Signaling ProcessAny subcellular process that is initated by a chemical or mechanical stimulus and results in a specific...
• Intrahepatic Bile DuctThe bile ducts that pass through and drain bile from the liver.
• Intra-individual variabilityFluctuations in an individual's physiologic (e.g., body weight), or behavioral characteristics (e.g...
• Intramural Research1. Research conducted by, or in support of, employees of EPA.
• IntramuscularInjections given in the muscle.
• Intranet1. Specific to EPA, the Intranet consist of those servers that are available only to EPA and those designated...
• Intraseasonal OscillationVariability on a timescale less than a season. One example is the Madden-Julian Oscillation.
• Intraspecies ExtrapolationExtrapolating toxicity data for different groups within the human population. There are two extrapolation...
• Intraspecific CompetitionCompetition between individuals of the same species (Ricklefs 1979:873).
• Intraspecific Genetic Diversity1. Variation among individuals for some heritable trait. Intraspecific genetic diversity may be partitioned...
• Intrastate ProductPesticide products once registered by states for sale and use only in the state. All intrastate products have...
• IntravasationThe entry of a foreign object into a blood vessel. This process is pertinent to the description of a cancer...
• intrinsic permeability1. A measure of the relative ease with which a permeable medium can transmit a fluid (liquid or gas)...
• INTRINSIC VALUEIn archives administration, the value of those permanent records that should be preserved in their original...
• Intrinsic Variation1. The variability (see definition) or inherent randomness in the real-world processes.
• Introduced Aquatic Plant(Introduced) plants that grow in water either floating on the surface, growing up from the bottom of the body...
• Introduced Genetic MaterialGenetic material that is added to, and remains as a component of, the genome of the recipient.
• Introduced Genetic Material CharacterizationThe following have been determined:(1) The function of all of the products expressed from the structural...
• Introduced Herbaceous Plant(An introduced) plant that is not woody.
• Introduced Plant(Plant) species that were intentionally or unintentionally brought by humans into a new geographic area or...
• Introduced Shrub(Shrub) species that were intentionally or unintentionally brought by humans into a new geographic area or...
• Introduced speciesA species that has been intentionally or inadvertently brought into a region or area. Also called an exotic...
• Introduced Tree(Tree) species that were intentionally or unintentionally brought by humans into a new geographic area or...
• Introduced Vine(Vine) species that were intentionally or unintentionally brought by humans into a new geographic area or...
• Introduction DateDate of manufacture of the first individual production engine of a given engine model or engine type...
• IntronA DNA sequence, or the RNA sequence transcribed from it, that interrupts the sequences coding for a gene...
• IntrusionAn unauthorized act of bypassing the security mechanisms of a network or information system.
• Inundation1. The submergence of land by water, particularly in a coastal setting, see also flooding.
• INUSA cause is an Insufficient but Necessary part of a condition which is, itself, Unnecessary but Sufficient to...
• In-Use Aircraft Gas Turbine EngineAircraft gas turbine engine which is in service.
• In-Use CreditAmount of emission reduction or exceedance, for each regulated pollutant, by a marine engine family below or...
• In-Use VehicleCustomer owned and operated vehicle which is not under the control of the manufacturer, dealerships or their...
• Invaded zoneThe annular interval of material around a drill hole where drilling fluid has replaced all or part of the...
• InvasionThe movement of one cell type into an area normally occupied by a different cell type.
• Invasive Animal Species1. An (animal) species that is brought into an area, usually by human movement, and begins to out compete...
• Invasive ManagementThe implementation of control measures to prevent the spread of invasive species or lessen their impacts when...
• Invasive Plant Species1. A (plant) species that is brought into an area, usually by human movement, and begins to out compete...
• Invasive Species1. These are species that are imported from their original ecosystem. They can out-compete native species as...
• invasivenessThe ability to degrade and migrate through the extracellular matrix.
• InventoriesThe emissions inventories for which the control strategy will be run. The inventories must have been loaded...
• Inventory1. A survey of agency records and nonrecord materials that is conducted primarily to develop records...
• Inventory AnalysisThe identification and quantification of energy, resource usage, and environmental emissions for a particular...
• Inventory ControlInventory Control refers to the tracking of information related to procured assets and resources with regard...
• Inventory FilterAn attribute of a strategy that specifies a general filter that can be entered using the same syntax as a SQL...
• Inventory FormThe uniform Tier I and Tier II emergency and hazardous chemical inventory forms published by EPA. These forms...
• Inventory selectionThe process of identifying emissions inventory data for inclusion in the General Purpose Release, based on a...
• Inventory SystemMethod of physically accounting for the quantity of ink, solvent, and solids used at one or more affected...
• Inventory (TSCA)Inventory of chemicals produced pursuant to Section 8 (b) of the Toxic Substances Control Act.
• Inverse Distance WeightingAn interpolation technique that estimates values in a raster from a set of sample points that have been...
• Inverse ModelA model that calculates the emissions causes from the pollutant observations
• Inversion1. An atmospheric condition caused by increasing temperature with elevation, resulting in a layer of warm air...
• Inversion, invertingThe process of deriving a model of the subsurface that is consistent with the geophysical data obtained...
• InvertThe lowest point of the channel inside a pipe, conduit, or canal.
• Invertebrate1. An animal that lacks a backbone. Aquatic invertebrates include squids, shrimps, crabs, mollusks and sea...
• Invertebrate Community IndexA measurement of the health of the macroinvertebrate community.
• Invertebrate TracheaA system of air-filled tubes in insects for the exchange oxygen and carbon dioxide between their tissues and...
• Invertebrates1. Animals without backbones: e.g. insects, spiders, crayfish, worms, snails, mussels, clams, etc.
• InverterA device that converts direct current electricity to alternating current either for stand-alone systems or to...
• InvertorDevice that converts direct current electricity to alternating current either for stand-alone systems or to...
• invertsThe bottom of a drainage facility along which the lowest flows pass.
• Investigating OfficialInspector General of the United States Environmental Protection Agency or an officer or employee of the...
• Investigation & Surveillance of Environmental CriminalsCollecting evidence required to determine responsibilities for criminal violations of federal environmental...
• Investigation CompleteThe event by which the State or EPA determines that the facility investigation is sufficient to support...
• Investigation Implementation BegunThe event by which the RCRA facility committed to begin any implementation in its Agency approved...
• Investigation ImpositionThe event by which the State or EPA imposes an obligation upon the owner/operator of a facility regulated by...
• Investigation Progress Reports ReceivedReceipt of reports submitted by the RCRA facility to the State or EPA during execution of the approved...
• Investigation Report ReceivedThe event by which a RCRA facility submits a written summary of the results of the approved investigation...
• Investigation Supplemental Information Deemed SatisfactoryThe event by which the State or EPA formally approves the investigation supplemental information.
• Investigation Supplemental Information ReceivedThe event by which the RCRA facility submits supplemental investigation information.
• Investigation Supplemental Information Requested by AgencyThe event by which the State or EPA requests information from the RCRA facility to modify, expand, amend...
• Investigation Workplan ApprovedThe event by which the State or EPA approves the investigation workplan submitted by the RCRA facility.
• Investigation Workplan Modification Requested by AgencyThe event by which the State or EPA requests that the RCRA facility modify its investigation workplan.
• Investigation Workplan Notice of Deficiency IssuedThe event by which the State or EPA issues a Notice of Deficiency to the Handler citing deficiencies in the...
• Investigation Workplan ReceivedThe event by which a RCRA facility submits an investigation workplan to the State or EPA.
• Investigational New Animal DrugDrug for which there is a valid exemption in effect under section 512(j) of the Federal Food, Drug, and...
• Investigational New DrugA new drug or biological drug that is used in a clinical investigation. The term also includes a biological...
• Investigational VaccineVaccine that has been approved by the Food and Drug Administration (FDA) for use in clinical trials on...
• Investigator Subject InteractionCommunication or interpersonal contact between investigator and subject.
• Investor-Owned Utility1. A private utility owned by investors and typically regulated by a state public utility commission.
• In-Vitro Research(Research) in an artificial environment outside a living organism or body. For example, some toxicity testing...
• In-Vivo Research(Research) within a living organism or body. For example, some toxicity testing is done on whole animals...
• IodineIodine is a naturally occurring element found in sea water and in certain rocks and sediments. There are non...
• IodophenolsOne of the hydrogen atoms on the phenol ring is replaced by iodine. The three isomers vary by where the...
• IodothyroninesIodinated derivatives of thyronine active in the regulation of energy metabolism.
• Ion1. An electrically charged atom, radical (such as SO42-), or molecule formed by the loss or gain of one or...
• Ion Channel1. Gated, ion-selective glycoproteins that traverse membranes. The stimulus for ion channel gating can be due...
• Ion Channel GatingThe opening and closing of ion channels due to a stimulus. The stimulus can be a change in membrane potential...
• Ion Composition ElucidationIon Composition Elucidation (ICE) utilizes selected ion recording with a double focusing mass spectrometer to...
• Ion Exchange1. Reversible exchange of ions adsorbed on a mineral or synthetic polymer surface with ions in solution in...
• Ion Exchange TechnologyDuring ion exchange treatment, water is passed through a resin containing exchangeable ions. Stronger binding...
• Ion Exchange TreatmentA common water-softening method often found on a large scale at water purification plants that remove some...
• Ion Pump InteractionIon Exchanger Interaction consists of temporary non-covalent binding of a molecule through intermolecular...
• Ion Transport ProcessAny cellular process involved in the translocation of charged macromolecules, solutes and solvents into or...
• Ionic BondingFormation of a chemical bond following a transfer of electrons between two ions with opposite charges.
• Ionic ConcentrationThe concentration of any ion in solution, usually expressed in moles per liter.
• Ionization1. The process by which a neutral atom loses or gains electrons, thereby acquiring a net charge and becoming...
• Ionization ChamberA device that measures the intensity of ionizing radiation.
• ionization potentialThe energy required to ionize a particular molecule.
• Ionizing Radiation1. Radiation that can strip electrons from atoms; e.g., alpha, beta, and gamma radiation.
• Ionizing Wet ScrubberThe only type of scrubber that uses electrostatic attraction as the primary technique for particle capture.
• IonomersIonically cross-linked thermoplastic polymers. They have hydrogen and ionic bonds.
• IonophoreChemical agents that increase the permeability of biological or artificial lipid membranes to specific ions...
• Ionosphere1. A complex atmospheric zone of ionized gases that extends between 50 and 400 miles (80 to 640 kilometers)...
• Ion-Selective ElectrodeAn electrode which can be used to measure the concentration of a particular ion in cells, tissues, or...
• Iontropic ReceptorType of neurotransmitter that allows the flow of ions into and out of a cell by opening the ion channels.
• IP AddressThis definition is based on Internet Protocol Version 4. See Internet Protocol Version 6 (IPv6) for a...
• IPCC Emissions ScenarioA set of emission scenarios from the IPCC Special Report on Emission Scenarios released in 2000 that describe...
• IPMAn integrated approach to controlling plant pests using careful monitoring of pests and weeds. It may include...
• IrisThe colored disc of the eye composed of connective tissue, epithelium, and endothelium. It separates the...
• IronA metallic element found in certain minerals, in nearly all soils, and in mineral waters. It has the atomic...
• Iron and Steel Coke PlantBy-product cokemaking operations that provide more than fifty percent of the coke produced to operations...
• Iron and Steel Cokemaking OperationThose by-product cokemaking operations other than merchant cokemaking operations.
• Iron and Steel FoundryFacility or portion of a facility that melts scrap, ingot, and/or other forms of iron and/or steel and pours...
• Iron and Steel ProductsProducts made primarily of iron or steel: Lined or unlined pipes and fittings, manhole covers and other...
• Iron Beaching Operationpouring hot molten iron from a torpedo car onto the ground when the iron from the blast furnace cannot be...
• Iron Blast FurnaceAll blast furnaces except ferromanganese blast furnaces.
• Iron ChelationIron Chelation involves non-covalent coordination bonding between iron and an organic chemical, often as part...
• Iron Control Agent1. In hydraulic fracturing iron control agents are used to keep insoluble iron compounds from forming and...
• Iron OreIron ore is a mineral substance which, when heated in the presence of a reductant, will yield metallic iron...
• Iron Oxidizing BacteriaBacteria which oxidize ferrous iron.
• Iron ParticleNano-sized particles of metallic iron which may be used to treat ground contaminated with chlorinated halogen...
• Iron Phosphate Conversion CoatingApplying a protective coating on the surface of a metal using a bath consisting of a phosphoric acid solution...
• Iron Removal ProcessCoagulation/filtration can be used to remove arsenic as well as iron from water.
• Iron-Based Treatment TechnologyEffective process for arsenic removal. Examples of this technology include chemical coagulation/filtration...
• IrradianceThe power transferred to a unit area of a surface by radiation from all directions within a hemisphere...
• Irradiated Food1. Food that has been briefly exposed to radioactivity (usually gamma rays) to kill insects, bacteria, and...
• Irradiation1. Exposure to radiation of wavelengths shorter than those of visible light (gamma, x-ray, or ultra- violet)...
• Irreparable HarmSignificant undesirable effects occurring after the date of permit issuance which will not be reversed after...
• IrreversibilitiesChanges that, once set in motion, cannot be reversed, at least on human time scales.
• Irreversible EffectEffect characterized by the inability of the body to partially or fully repair injury caused by a toxic agent.
• Irreversible InhibitorParticle that binds to an enzyme and changes its chemistry permanently.
• Irrigated LandscapeLand that shows evidence of being irrigated during the year of the inventory or of having been irrigated...
• Irrigation1. Supplying water to grass, trees, and other plants.
• Irrigation DitchConstructed or excavated channel used to convey water. [40 CFR 120.2 (CFR 2020)
• Irrigation EfficiencyThe amount of water stored in the crop root zone compared to the amount of irrigation water applied.
• Irrigation Infrastructure(Infrastructure to support) applying water or wastewater to land areas to supply the water and nutrient needs...
• Irrigation Return Flow1. Surface and subsurface water that leaves a field after the application of irrigation water.
• Irrigation Scheduling1. An automated method for optimizing outdoor water use by matching the watering schedule to plant needs.
• Irrigation WaterWater which is applied to land usually for the purpose of growing plants
• Irrigation Water UseWater application on lands to assist in the growing of crops and pastures or to maintain vegetative growth in...
• Irritant1. A substance that can cause irritation of the skin, eyes, or respiratory system. An irritant can cause an...
• IschiumOne of three bones that make up the coxal bone of the pelvic girdle. In tetrapods, it is the part of the...
• IslandAn area of land completely surrounded by water - or an elevated area of land surrounded by swamp or marsh...
• Island RiseAn area that lies at the deepest part of an island margin between the continental slope and the abyssal...
• Island ShelfThat part of the continental margin that is between the shoreline and the continental slope (or a depth or...
• Island Shore ComplexThis feature includes the land-water interface zone and contains geoforms across a diversity of scales. For...
• Island Slope1. That part of the continental margin that is between the continental shelf and the continental rise (if...
• Islets of LangerhansIrregular microscopic structures consisting of cords of endocrine cells that are scattered throughout the...
• IsobutaneParaffinic branch chain hydrocarbon with molecular formula C4H10.
• IsobutyleneOlefinic branch chain hydrocarbon with molecular formula C4H8.
• ISO-Certified AuditorAuditor who is either certified by the Registrar Accreditation Board (in the United States) as being...
• IsoconcentrationMore than one sample point exhibiting the same isolate concentration.
• IsocyanateReactive chemical grouping composed of a nitrogen atom bonded to a carbon atom bonded to an oxygen atom; or a...
• IsodrinThe pesticide 1,4:5,8-Dimethanonaphthalene,1,2,3,4,10,10-hexacholoro-1,4,4a,5,8,8a-hexahydro-, (1alpha...
• Isoenzyme1. An enzyme performing the same function as another enzyme but having a different set of amino acids. The...
• Isoflavones3-Phenylchromones. Isomeric form of flavonoids in which the benzene group is attached to the 3 position of...
• IsohyetA line on a map along which all points receive the same amount of precipitation.
• Isokinetic SamplingSampling in which the linear velocity of the gas entering the sampling nozzle is equal to that of the...
• Isola EffectEnvironmental issues that are unique to island systems. This uniqueness takes into account the physical...
• isolateIsolate refers to a laboratory maintained stock or controlled propagation through host passages source of...
• Isolated Intermediate1. Product of a process. An isolated intermediate is usually a product of a chemical synthesis, fermentation...
• Isolated Rural Nonattainment and Maintenance AreaAreas that do not contain or are not part of any metropolitan planning area as designated under the...
• Isolated WetlandWetland that is not contiguous, bordering or neighboring with respect to other Waters of the US are...
• Isolated wetlandsWetlands that are not contiguous, bordering or neighboring with respect to other Waters of the US are...
• IsolationSeparation of infected persons to prevent transmission to susceptible ones. Isolation refers to separation of...
• Isolation due to CircumstancesOccurs when people are isolated at home because of weather or other environmental events, such as an ice...
• IsomerAn individual compound with a common structure (dioxin, furan, or biphenyl), only differing by the position...
• IsomerasesA class of enzymes that catalyze geometric or structural changes within a molecule to form a single product...
• IsomerismThe phenomenon whereby certain chemical compounds have structures that are different although the compounds...
• Isomerization1. A reaction that catalytically converts straight-chain hydrocarbon molecules into branched-chain molecules...
• IsoplethThe line or area represented by an isoconcentration.
• Isopod1. A tiny, bug-like crustacean.
• IsopreneAn unsaturated pentahydrocarbon, Isoprene is found in certain plants or obtained by distillation of...
• IsoprenoidsA class of compounds composed of repeating 5-carbon units of hemiterpenes.
• Isoprenylation InhibitionIsoprenylation Inhibition involves interference with, or restraint of, enzymatic activities involved in...
• Isoprenylation ProcessThe covalent addition of prenyl and multiprenyl residues to a macromolecule.
• IsopropanolAn isomer of 1-propanol. It is a colorless liquid having disinfectant properties. It is used in the...
• Isostatic AdjustmentThe process whereby lateral transport at the Earth's surface from erosion or deposition is compensated for by...
• IsotoniaA solution having the same effective osmotic pressure as the body fluid to which it is compared
• Isotope1. A variation of an element that has the same atomic number of protons but a different weight because of the...
• Isotope DilutionA technique for mass spectrometric quantitation of an analyte of interest in which a stable isotope-labeled...
• Isotope Dilution Quantitation1. A means of determining a naturally occurring (native) compound by reference to the same compound in which...
• Isotope Ratio Mass SpectrometryMethod of analysis in which ions are separated by mass with the goal of determining the relative abundance of...
• IsotopesAtoms of the same element that have the same atomic number, but a different mass number; unstable isotopes...
• IsotretinoinA topical dermatologic agent that is used in the treatment of ACNE VULGARIS and several other skin diseases...
• isotropicThe condition in which hydraulic properties of an aquifer are equal when measured in any direction.
• isotropy1. The condition in which the properties of interest (generally hydraulic properties of the aquifer) are the...
• ISS SupervisorsThese supervisors approve ECMS registration requests in Identity Self Service (ISS).
• IssueA well defined, discrete subject of controversy. When the point of controversy can only be vaguely defined or...
• Issue Contract & IAG Policies, Procedures, Guidance & TrainingEstablish and maintain Agency-specific policies, procedures and guidance with respect to contract and...
• Issue Goods Acquisition Policies, Procedures, Guidance & TrainingEstablish and maintain Agency-specific policies, procedures and guidance with respect to contract and...
• Issue PermitsThe issuance of permits, licenses, or registrations to industry or other organizations, pursuant to...
• Issue Request LetterEPA issues letters under the authority of Section 104(e) to gather information related to (1) the...
• Issue Request Letters (104E)EPA issues letters under the authority of Section 104(e) to gather information related to (1) the...
• Issue Water Discharge PermitsActivities to support the issuance and maintenance of permits regulating point sources that discharge...
• Issuing AgencyUnless otherwise specifically indicated, means the State or local air pollution control agency to which a...
• IT Infrastructure MaintenanceIT Infrastructure Maintenance involves the planning, design, and maintenance of an IT infrastructure to...
• IT Risk AssessmentActivities to understand and document potential risks from IT security failures that may cause loss of...
• IT Security1. IT Security involves all functions pertaining to the securing of federal data and systems through the...
• IT Security Program ManagementActivities to manage the EPA IT Security Program.
• IT Security Training & AwarenessActivities to train staff in IT risk assessment, security infrastructure operations and maintenance, and IT...
• IT Vulnerability Management & Incident ResponseActivities to identify and quantify the vulnerabilities or potential threats to assets and capabilities of...
• ITEM1. A document.
• Iteration1. Repetition of a process; in particular, repetition of the causal analysis process with new data or...
• Iterative ReductionA method of calculating a PRG that involves successively lowering the concentration term until the calculated...
• Iterative TechniqueMethod involving repeated actions with the goal of obtaining greater precision in the result; often used in...
• Iterative TruncationA method of calculating a PRG that involves developing an expression for the concentration term in which...
• i-Type SemiconductorSemiconductor material that is left intrinsic, or undoped so that the concentration of charge carriers is...
• IxodidaeA family of hardbacked TICKS, in the subclass ACARI. Genera include DERMACENTOR and IXODES among others.

1,291 of 30,736 terms in Environment terminology (MLC-0121). Request the full dataset.