Environment terminology · MLC-0121

Environment terms: C (3,254)

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Chlorinated hydrocarbons1. Chemicals containing only chlorine, carbon, and hydrogen. These include a class of persistent...
Chlorinated insecticidePesticides such as DDT made from chlorinated hydrocarbons that linger in the environment and accumulate in...
Chlorinated plasticsSolid polymeric materials that contain chlorine in the polymer chain, such as polyvinyl chloride (PVC) and...
Chlorinated solvent1. An organic solvent containing chlorine atoms(e.g., methylene chloride and 1,1,1-trichloromethane). Uses of...
Chlorinated solvent dechlorinationWhere a hydrogen atom replaces a halogen atom in the solvent with the elimination of a chloride ion, often...
Chlorinated solvents, see Chlorinated solvent
Chlorinated terphenylChemical substance, CAS No. 61788-33-6, comprised of chlorinated ortho-, meta-, and paraterphenyl.
Chlorination1. Adding chlorine to water or wastewater, generally for the purpose of disinfection, but frequently for...
Chlorinator1. (KLOR-uh-NAY-ter) A metering device which is used to add chlorine to water.
Chlorine1. •Chlorine is an element used in industry and found in some household products. •Chlorine is sometimes in...
Chlorine demandChlorine demand is the difference between the amount of chlorine added to water and the amount of residual...
Chlorine plant bypass scrubberWet scrubber that captures chlorine gas during a chlorine plant shut down or failure.
Chlorine productionElectrolysis of solutions of Sodium Chloride (rock salt)
Chlorine requirementThe amount of chlorine which is needed for a particular purpose. Some reasons for adding chlorine are...
Chlorine substitutionSubstituting hydrogen atoms for chlorine atoms, particularly useful for solvents
Chlorine-based treatment technologyAn example of chemical disinfection used to control waterborne diseases.
Chlorine-contact chamberThat part of a water treatment plant where effluent is disinfected by chlorine.
Chlorine-free treatment technologyChlorine-free treatment uses ozone and nanofiltration processses to disinfect or remove pathogens from water.
ChloroacetamidesPre-emergent herbicides.
Chloroacetic acidAcetic acid with a chlorine atom substituted for a methyl hydrogen atom. Commonly used as a reactant in...
ChlorobiA phylum of anoxygenic, phototrophic bacteria including the family Chlorobiaceae. They occur in aquatic...
ChlorofluorocarbonA compound consisting of chlorine, fluorine, and carbon. Chlorofluorocarbons (CFCs) are very stable in the...
Chlorofluorocarbons, see Chlorofluorocarbon
ChlorofluoromethanesA group of methane-based halogenated hydrocarbons containing one or more fluorine and chlorine atoms.
ChlorolichenA lichen that has a green alga for its photobiont.
ChloromethylbutenoneChloromethylbutenone (CMBO), the product of the oxidation of isoprene by atomic Cl and a unique marker for...
Chlorophenolic(klor-o-FEE-NO-lick) Chlorophenolic compounds are phenolic compounds (carbolic acid) combined with chlorine.
Chlorophenoxy1. (KLOR-o-fuh-KNOX-ee) A class of herbicides that may be found in domestic water supplies and cause adverse...
ChlorophyllA chemical mixture or compound found in the chloroplasts of plant cells and gives plants their green color...
Chlorophyll a1. The predominant type of chlorophyll found in algae. Chlorophyll a is used as an indicator of nutrient...
Chlorophyll bA chlorophyll with the molecular formula of C55H70O6N4Mg. Less commonly found in nature than chlorophyll a.
Chlorophyll maximumA feature in deeper water columns (often in the ocean), where phytoplankton production is locally high at...
Chlorophyll minimumA layer of low chlorophyll - and hence phytoplankton - concentration (relative to adjacent waters) due to...
Chlorophylls, see Chlorophyll
ChlorophytaA phylum of photosynthetic eukaryota bearing double membrane-bound plastids containing chlorophyll a and b...
Chloroplast1. Large cellular organelle that contains chlorophyll, consists of a complex lammelar system of membranes...
Chloroplast chromosomeCircular DNA found in the photosynthesizing organelle (chloroplast) of plants instead of the cell nucleus...
Chlororganic(klor-or-GAN-nick) Organic compounds combined with chlorine. These compounds generally originate from, or are...
Chlorosis1. Discoloration of normally green plant parts caused by disease, lack of nutrients, or various air...
ChlorosomeAntenna systems which are the principal light-harvesting complexes in some bacteria
Choctawhatchee-EscambiaThe coastal drainage and associated waters from the Apalachicola Bay drainage boundary to the Mobile Bay...
Cholera(A disease caused by) a toxic secreted by Vibrio cholerae, which is a natural bacterial enterotoxin...
CholesterolThe principal sterol of all higher animals, distributed in body tissues, especially the brain and spinal...
Cholesterol homeostasisAny of the processes involved in the maintenance of an internal equilibrium of cholesterol within an organism...
Cholesterol synthesis inhibitionCholesterol Synthesis Inhibition involves interference with, or restraint of, the enzymatic formation of the...
Choline acetyltransferaseCholine O-acetyltransferase (748 aa, ~83 kDa) is encoded by the human CHAT gene. This protein is involved in...
Choline chlorideA basic constituent of lecithin that is found in many plants and animal organs. It is important as a...
Cholinergic receptorCell surface proteins that bind acetylcholine with high affinity and trigger intracellular changes...
CholinesteraseAn enzyme found in animals that regulates nerve impulses by the inhibition of acetylcholine. Cholinesterase...
Cholinesterase activityCatalysis of the reaction: an acylcholine + H2O = choline + a carboxylic acid anion.
Cholinesterase inhibitionInhibition of an enzyme of the hydrolase class that catalyzes the cleavage of the acyl group from various...
Cholinesterase inhibitorDrugs that inhibit cholinesterases. The neurotransmitter acetylcholine is rapidly hydrolyzed, and thereby...
Cholinesterase-inhibiting pesticide1. Organophosphates and the Carbamates.
Cholinesterases, see Cholinesterase
ChoppingA mechanical treatment whereby vegetation is concentrated near the ground and incorporated into the soil to...
ChoriogenesisThe formation of chorion (egg shell) in insects.
ChoroidA blood vessel-containing membrane of the eye that lies between the retina and the sclera.
Chowan-RoanokeThe coastal drainage and associated waters from and including the Back Bay drainage to Oregon Inlet...
Chromaffin cell1. Cell that stores epinephrine secretory vesicles. Characteristically, it is located in the adrenal medulla...
Chromaffin systemThe cells of the body which stain with chromium salts. They occur along the sympathetic nerves, in the...
Chromaffin system cellThe cells of the body which stain with chromium salts. They occur along the sympathetic nerves, in the...
Chromate conversion coatingForming a conversion coating (protective coating) on a metal by immersing or spraying the metal with a...
Chromate wasteWaste containing chromium
Chromated copper arsenate1. A water-borne preservative containing active ingredients that are inorganic metal oxides, or less...
ChromatesSalts of chromic acid containing the CrO(2-)4 radical.
ChromatinThe material of chromosomes. It is a complex of DNA; histones; and nonhistone proteins ( chromosomal...
Chromatin remodelingChromatin Remodeling involves alterations of the content or activity of DNA-binding and chromatin-associated...
Chromatin structural processAny biochemical process that results in the specification, formation or maintenance of the physical structure...
ChromatingForming a conversion coating (protective coating) on a metal by immersing or spraying the metal with a...
Chromatography1. Techniques used to separate mixtures of substances based on differences in the relative affinities of the...
Chrome pigmentChrome yellow, chrome orange, molybdate chrome orange, anhydrous and hydrous chromium oxide, chrome green...
Chrome tanProcess of converting hide into leather using a form of chromium.
Chromic acid1. Chromium trioxide (CrO3). It is produced by the electrolytic reaction or acidification of sodium...
Chromic oxideCr2O3. In the production of chromic oxide, ammonium sulfate and sodium dichromate that have been concentrated...
Chromite oreOxide of chromium and iron (FeCr2O4) that is the primary feedstock for chromium compounds manufacturing.
Chromium1. Please see the ATSDR fact sheet for chromium.
Chromium anodizing tankReceptacle or container along with the following accompanying internal and external components needed for...
Chromium compoundsIncludes any unique chemical substance that contains chromium as part of that chemical's infrastructure...
Chromium compounds (chromium VI compounds: 0.1; chronmium III compounds: 1.0), see Chromium compounds
Chromium compounds manufacturingAny process that uses chromite ore as the basic feedstock to manufacture chromium compounds, primarily sodium...
Chromium compounds manufacturing facilityCollection of processes and equipment at a plant engaged in chromium compounds manufacturing.
Chromium Drag-out DestructionUnit operation performed following chromium-bearing operations to reduce hexavalent chromium that is “dragged...
Chromium electroplating tankReceptacle or container along with the following internal and external components needed for chromium...
Chromium-based water treatment chemicalAny combination of chemical substances containing chromium used to treat water.
Chromobacterium subtsugae strain PRAA4-1 cells and spent fermentation mediaT is a gram-negative, violet-pigmented bacterium with insecticidal and miticidal capabilities
Chromosomal inversion processAny type of genetic recombination involving rearrangement of segments of DNA within a single chromosome, such...
Chromosomal translocation process1. Any type of genetic recombination involving exchange of DNA between non-homologous chromosomes, which...
Chromosome1. The self-replicating genetic structure of cells containing the cellular DNA that bears in its nucleotide...
Chromosome condensationA process of progressive and tight packing of dispersed replicated interphase chromatin into compact...
Chromosome disordersClinical conditions caused by an abnormal chromosome constitution in which there is extra or missing...
Chromosome rearrangementA structural alteration in a chromosome, usually involving breakage and reattachment of a segment of...
Chromosome segregationThe separation of chromosomes into daughter cells during cell division.
Chromosome translocation1. A chromosome alteration in which a whole chromosome or segment of a chromosome becomes attached to or...
Chronic1. Used to describe recurring symptoms or disease.
Chronic acidificationGenerally refers to surface waters that remain acidified (ANC<0) regardless of variations in hydrologic...
Chronic bronchitis1. A subcategory of chronic obstructive pulmonary disease. The disease is characterized by hypersecretion of...
Chronic effect1. An adverse effect on any living organism in which symptoms develop slowly over a long period of time or...
Chronic exposure1. Contact with a substance that occurs over a long time (more than 1 year)
Chronic health effect1. The possible result of exposure over many years to a drinking water contaminant at levels above its...
Chronic health effects, see Chronic health effect
Chronic health hazardPersistent or prolonged injury
Chronic human healthThe RSEI model addresses both chronic effects and chronic exposures related to human health. Chronic effects...
Chronic inhalation studyProlonged and repeated exposure by inhalation for the life span of the test animal; technically, two years in...
Chronic intakeThe long term period over which a substance crosses the outer boundary of an organism without passing an...
Chronic kidney diseasesGradual and usually permanent loss of kidney function resulting in renal failure. Causes include diabetes...
Chronic obstructive pulmonary disease1. A chronic and progressive lung disorder characterized by the loss of elasticity of the bronchial tree and...
Chronic reference concentrationAn estimate (with uncertainty spanning perhaps an order of magnitude) of a continuous inhalation exposure for...
Chronic reference doseAn estimate (with uncertainty spanning perhaps an order of magnitude) of a daily oral exposure for a chronic...
Chronic responseThe response of (or effect on) an organism to a chemical that is not immediately or directly lethal to the...
Chronic studyA toxicity study designed to measure the (toxic) effects of chronic exposure to a chemical.
Chronic testsA toxicity test used to study the effects of continuous, long-term exposure of a chemical or other...
Chronic toxicity1. The capacity of a substance to cause long-term poisonous health effects in humans, animals, fish, and...
Chronic toxicity assay1. (Analysis for) the capacity of a substance to cause adverse human health effects as a result of chronic...
Chronic viral hepatitisChronic hepatitis caused by viruses, most commonly hepatitis viruses B and C.
Chronic wasting diseaseChronic wasting disease (CWD) is a transmissible spongiform encephalopathy (TSE) of deer and elk. To date...
ChryseneAn aromatic hydrocarbon in coal tar, allied to naphthalene and anthracene. It is a white crystalline...
ChrysophytaA family of microscopic freshwater eukaryota, commonly known as golden algae. They share many features with...
ChrysotileA mineral in the serpentine mineral group that occurs in the asbestiform habit. Chrysotile generally occurs...
Chrysotile asbestosAsbestiform variety of a hydrated magnesium silicate mineral, with relatively long and flexible crystalline...
ChurningThe process of stirring and agitating cream in the process of making butter. Churning causes the fat globules...
ChuteAn opening in the ground where ore is allowed to pass from one level to another. It is the structure built to...
CiliaTiny, projecting "hairs" on a cell or microscopic organism that beat rhythmically to aid in movement.
CiliateAny of the phylum Ciliophora of ciliate protozoans
CiliophoraA phylum of eukaryotes characterized by the presence of cilia at some time during the life cycle. It...
CimetidineA histamine congener, it competitively inhibits histamine binding to histamine H2 receptors. Cimetidine has a...
CinogenicAble to induce a cancer response at the cellular level.
Circle of influenceThe circular outer edge of a depression produced in the water table by the pumping of water from a well.
CircuitThe complete path of an electric current, including the generating apparatus or other source; or, a specific...
Circuit breaker1. A safety device in an electrical circuit that automatically shuts off the circuit when it becomes...
Circuit peak load managementAn application utilizing sensors, information processors, communications, and control systems designed to...
Circuit rider programInvolves designating one or more people to provide technical assistance to multiple local governments in a...
Circular economyEconomy that keeps materials and products in circulation for as long as possible. A circular economy reduces...
Circulating fluidized bed combustorFluidized bed combustor in which the majority of the fluidized bed material is carried out of the primary...
Circulating fluidized boilerBoiler utilizing a fluidized bed combustion process.
Circulating lipoproteinLipid-protein complexes involved in the transportation and metabolism of lipids in the body. They are...
CirrocumulusA cirriform cloud characterized by thin, white patches, each of which is composed of very small granules or...
CirrostratusA cloud of a class characterized by a composition of ice crystals and often by the production of halo...
CirrusHigh-level clouds (16,000 feet or higher), composed of ice crystals and appearing in the form of white...
Cirsium arvenseCanada thistle is an herbaceous perennial with erect stems 1½-4 feet tall, prickly leaves and an extensive...
Cistern1. (SIS-turn) A small tank (usually covered) or a storage facility used to store water for a home or farm...
CitationA citation is a reference to another work that identifies it. A citation explicitly states who wrote the...
CITES speciesSpecies (675 as of this writing) listed under the 1975 Convention on International Trade in Endangered...
Citizenship statusPeople who indicate that they were born in the United States, Puerto Rico, a U.S. Island Area, or abroad of a...
Citric acidA key intermediate in metabolism. It is an acid compound found in citrus fruits. The salts of citric acid...
Citric acid producerOne of the largest commercial uses of Aspergillus fungi is in the production of soft drinks. The extraction...
CitrullineA non-essential amino acid in humans, Aspartic Acid has an overall negative charge and plays an important...
Citrus huanglongbingCitrus huanglongbing (HLB) is one of the most devastating diseases of citrus worldwide. The disease is...
Citrus variegated chlorosisCitrus variegated chlorosis (CVC) caused by the CVC strain of Xylella fastidiosa is a serious disease of...
City1. The name of the city, town, village, or other municipality where a site is located or an incident occurs...
City boundaries, see City boundary
City boundary"Definition 1: The City Boundaries layer includes incorporated cities and Census Designated Places from the...
City fuel economy1. Estimated miles-per-gallon in the city. City Fuel Economy represents urban driving, in which a vehicle is...
City fuel economy testTest procedures specified in 40 CFR part 86, except as those procedures are modified in these protocols.
City gateLocation at which natural gas ownership or control passes from one party to another, neither of which is the...
City waterWater that meets U.S. EPA drinking water standards.
Civil actionA formal lawsuit, filed in court, against a person who has either failed to comply with a statutory or...
Civil administrative actionNon-judicial enforcement action taken by EPA or a state under its own authority, without involving a judicial...
Civil enforcement1. Brings parties responsible for violating environmental laws into compliance with those laws, and ranges...
Civil investigationCivil investigations are defined as an extraordinary, detailed assessment of a regulated entity’s compliance...
Civil judicial actionFormal lawsuits. They are filed in court, against persons or entities that have failed to: comply with...
Civil liabilityLegal accountability for the party which did the wrong pay the injured party for damages, includes tort...
Civil penaltyCivil Penalties are monetary assessments to be paid by a person or regulated entity in connection with a...
Civilian operationsCivilian Operations describes the direct provision of a non-military service for the citizen by government...
Civilian workerThe National Compensation Survey defines Civilian Workers as the sum of all private industry and State and...
CladdingArt of producing a composite metal containing two or more layers that have been metallurgically bonded...
Cladocerans/CopepodsZooplankton that together make up a major component of the zooplanktonic community. They live in the water...
CladophoraA long filamentous type of green algae that attaches to hard surfaces, particularly near the shoreline...
CladosporiumA mitosporic Loculoascomycetes fungal genus including some economically important plant parasites...
Claim1. The portion of mining ground held under the Federal and local laws by one claimant or association, by...
Claim in bankruptcy proceedingLegal action performed by EPA Regional attorneys to establish EPA as a creditor when a potentially...
Claim (Mineral Extraction), see Claim
Claim (on a policyholder)The assertion of a legal right alleging liability or responsibility on the part of the insured, arising out...
Claim (on an insurer), see Claim
Claim proceedingThe entire process of review of a claim conducted pursuant to this part that is initiated by a Request for a...
Claim settlementAct of considering, ascertaining, adjusting, determining or otherwise resolving a claim.
Claimant1. As defined by section 1001 of the OPA means any person or government who presents a claim for compensation...
Claims made based coverageThe trigger of coverage is a claim being made and reported during the policy period; therefore, insurance...
Claims officialThe Assistant Administrator or the Regional Administrator or his delegatee who makes the initial decision...
Clandestine actionAn action done secretly, often to hide an illicit objective.
Clarification1. Clearing action that occurs during wastewater treatment when solids settle out. This is often aided by...
Clarifier1. A large circular or rectangular tank or basin in which water is held for a period of time, during which...
Clarity and completeness1. One of EPA's five Assessment Factors (see definition) that describes the degree of clarity and...
Class1. A set of objects that share a common structure and behavior. The structure of a class is determined by the...
Class 5X16Class 5X16 injection wells, a subclass of Class V wells, are Spent-Brine Return Flow Wells, used to re-inject...
Class A operatorIndividual who has primary responsibility to operate and maintain the UST system in accordance with...
Class B operatorIndividual who has day-to-day responsibility for implementing applicable regulatory requirements established...
Class C operatorIndividual responsible for initially addressing emergencies presented by a spill or release from an UST...
Class I area1. Under the Clean Air Act. a Class I area is one in which visibility is protected more stringently than...
Class I engineRelating to nonhandheld engines with total displacement below 225 cc. See § 1054.101 for special provisions...
Class I equivalent methodEquivalent method for PM2.5 or PM10-2.5 which is based on a sampler that is very similar to the sampler...
Class I freight railroad1. Defined by the American Association of Railroads each year based on annual operating revenue. A railroad...
Class I injection well(Used to) Inject hazardous wastes, industrial non-hazardous liquids, or municipal wastewater beneath the...
Class I municipal waste combustor unitSmall municipal waste combustion units subject to this subpart that are located at municipal waste combustion...
Class I ozone-depleting substanceOne of several groups of chemicals with an ozone-depletion potential of 0.2 or higher. Class I...
Class I ozone-depleting substances, see Class I ozone-depleting substance
Class I railroadRailroad that has been classified as a Class I railroad by the Surface Transportation Board.
Class I sludge management facility1. Any POTW identified under 40 CFR 403.8(a) as being required to have an approved pretreatment program...
Class I substance1. One of several groups of chemicals with an ozone depletion potential of 0.2 or higher, including CFCS...
Class I wellsTechnologically sophisticated wells that inject wastes into deep, isolated rock formations below the...
Class II areaAttainment areas that are neither industrialized nor meet the specific requirements for classification as...
Class II engineRelating to nonhandheld engines with total displacement at or above 225 cc.
Class II equivalent methodEquivalent method for PM2.5 or PM10-2.5 that utilizes a PM2.5 sampler or PM10-2.5 sampler in which integrated...
Class II injection well(Used to) Inject brines and other fluids associated with oil and gas production, and hydrocarbons for...
Class II municipal waste combustor unitSmall municipal combustion units subject to this subpart that are located at municipal waste combustion...
Class II ozone-depleting substance1. A chemical with an ozone-depletion potential of less than 0.2. Currently, all hydrochlorofluorocarbons are...
Class II ozone-depleting substances, see Class II ozone-depleting substance
Class II railroadRailroad that has been classified as a Class II railroad by the Surface Transportation Board.
Class II substance1. A substance with an ozone depletion potential of less than 0.2. All HCFCs are currently included in this...
Class II wellsWells that inject brines and other fluids associated with oil and gas production, or storage of hydrocarbons...
Class III areaIndustrialized attainment areas. They are protected by the Prevention of Significant Deterioration (PSD)...
Class III engineRelating to handheld engines with total displacement below 20 cc.
Class III equivalent methodEquivalent method for PM2.5 or PM10-2.5 that is an analyzer capable of providing PM2.5 or PM10-2.5 ambient...
Class III injection well1. Class III wells inject fluids to dissolve and extract minerals such as uranium, salt, copper, and sulfur...
Class III railroadRailroad that has been classified as a Class III railroad by the Surface Transportation Board.
Class III wellsWells that inject fluids associated with solution mining of minerals. Mining practices that use Class III...
Class IV engineRelating to handheld engines with total displacement at or above 20 cc but below 50 cc.
Class IV injection well(Used to) Inject hazardous or radioactive wastes into or above USDWs. These wells are banned unless...
Class IV wellsWells that inject hazardous or radioactive wastes into or above a USDW. These wells are banned unless...
Class [of Control Measure]Characterizes the status of a control measure. Currently available classes are Emerging (feasible, but not...
Class (pipe and fittings)The working pressure rating of a specific pipe for use in water distribution systems which includes...
Class T3 engineAll aircraft gas turbine engines of the JT3D model family.
Class T8 engineAll aircraft gas turbine engines of the JT8D model family.
Class TF engineAll turbofan or turbojet aircraft engines or aircraft engines designed for applications that otherwise would...
Class TP engineAll aircraft turboprop engines.
Class TSS engineAll aircraft gas turbine engines employed for propulsion of aircraft designed to operate at supersonic flight...
Class V engineRelating to handheld engines with total displacement at or above 50 cc.
Class V injection wellA shallow well used to place a variety of fluids at shallow depths below the land surface, including a...
Class V wellThis is a term for all injection wells which are not explicitly identified as Class I, Class II, Class III or...
Class V wells, see Class V well
Class VI injection well(Used to) Inject Carbon Dioxide (CO2) for long term storage, also known as Geologic Sequestration of CO2.
Class VI wellsWells that inject carbon dioxide for the purposes of long-term storage, also known as CO2 geologic...
Classes of contaminantsClasses of contaminants indicates which categories of contaminants have been identified through the...
Classical statistical methodEstimating the population exposure distribution directly, based on measured values from a representative...
Classical statistical methods, see Classical statistical method
Classification1. The process of determining the sequence or order in which to arrange documents. See also ARRANGEMENT, FILE...
Classification and regression treeTechnique for data analysis which recursively partitions observations in a matched data set, consisting of a...
Classification componentThe NESCS Plus uses five dimensions to classify final ecosystem services -- Environment, Ecological...
Classification system1. Provides an organized (and often hierarchical) structure, through well-defined categories that allow one...
Classified information1. Records or information requiring, for national security reasons, safeguards against unauthorized...
Classified materialAny document, apparatus, model, film, recording, or any other physical object from which classified...
Classified national security informationInformation that has been determined pursuant to Executive Order 13526, “Classified National Security...
Classified researchResearch that the government keeps secret to protect national security. Access to classified research is...
Classified wasteWaste material that has been given security classification in accordance with 50 U.S.C. 401 and Executive...
Clastic sedimentary rock1. Rocks consisting of fragments, deposited as sand, silt, gravels, or with organic materials on beaches...
ClastsIndividual sedimentary particles such as a grain of sand, pebble, or boulder that make up a sedimentary rock...
Claus sulfur recovery plantProcess unit which recovers sulfur from hydrogen sulfide by a vapor-phase catalytic reaction of sulfur...
ClauseA term used to identify a particular part of a policy or endorsement.
ClavicepsA genus of ascomycetous fungi, family Clavicipitaceae, order Hypocreales, parasitic on various grasses (...
Claviceps purpureaThe ergot mold, Claviceps purpurea, is the cause of the earliest recognized human mycotoxicosis, ergotism...
ClavicleA bone on the ventral side of the shoulder girdle, which in humans is commonly called the collar bone.
Clay1. One type of soil particle with a diameter of approximately one ten-thousandth of an inch.
Clay ceramics manufacturing facility1. Plant site that manufactures pressed tile, sanitaryware, dinnerware, or pottery. For the purposes of this...
Clay ceramics metal hazardous air pollutantOxide or other compound of chromium, lead, manganese, or nickel, which were listed for Clay Ceramics...
Clay flocculationSoil clay particles, due to their negativley charged nature, tend to repel each other and remained dispersed...
Clay mineralSix types of clays are mined in the United States: ball clay, bentonite, common clay, fire clay, fuller's...
Clay soil1. A soil containing more than 40 percent clay, but less than 45 percent sand, and less than 40 percent silt.
Clay stabilizerSubstances used to keep clay particles from swelling and moving and thereby blocking the formation matrix in...
Clean Air Act1. To improve, strengthen, and accelerate programs for the prevention and abatement of air pollution.
Clean Air Interstate RuleRule to reduce the interstate transfer of fine particulate material and ozone by establishing State-level...
Clean Air Markets DivisionClean Air Markets Division (of EPA's Office of Air, OAP, located in Washington, DC). Administers several...
Clean air shelterPublic spaces for people who are displaced by wildfire or smoke.
Clean ballastEither seawater or freshwater that is transferred into and out of dedicated tanks to adjust a surface ship's...
Clean cellulosic biomass1. Those residuals that are akin to traditional cellulosic biomass, including, but not limited to...
Clean charge1. Furnace charge materials, including molten aluminum; T-bar; sow; ingot; billet; pig; alloying elements...
Clean closureThe process of completely removing all waste that was treated, stored, or disposed in a hazardous waste unit.
Clean coal technologyAny technology not in widespread use prior to the Clean Air Act Amendments of 1990. This Act will achieve...
Clean coal-fired steam generating unit reactivationAny physical change or change in the method of operation associated with the commencement of commercial...
Clean compliance historyFor the purposes of subpart Y, a record of no MCL violations under § 141.63; no monitoring violations under §...
Clean dataAir quality monitoring data determined by EPA to meet the applicable requirements of 40 CFR Parts 50 and 58...
Clean dry biomassAny biomass-based solid fuel that have not been painted, pigment-stained, or pressure treated, does not...
Clean fuelsBlends or substitutes for gasoline fuels, including compressed natural gas, methanol, ethanol, and liquefied...
Clean lumberWood or wood products that have been cut or shaped and include wet, air-dried, and kiln dried wood products...
Clean sedimentSediment that is not contaminated by chemical substances. Pollution caused by clean sediment refers to the...
Clean up contaminated landActivities to clean up contaminated land to return it to beneficial use.
Clean Water Act1. To provide for water pollution control activities in the Public Health Service of the Federal Security...
Clean Water Act hazardous substanceAny hazardous substance designated in 40 CFR part 116.
Clean Water Act priority pollutantsThe EPA has listed the CWA priority pollutants at 40 CFR part 423, Appendix A.
Clean Water Act priority pollutants categoryAll 126 pollutants that EPA currently defines as priority pollutants. Section 3.3.2 of the Technical Users...
Clean Water Act Section 303(d)Annual report to Congress from EPA that identifies those waters for which existing controls are not...
Clean Water Act Section 303(d) listed impaired waters (Category 5)A Clean Water Act Section 303(d) listed impaired water is a waterbody that is impaired or threatened and...
Clean Water Act Section 305(b)1. Biennial reporting requires description of the quality of the Nation's surface waters, evaluation of...
Clean Water Act Section 319 projectsUnder Section 319 of the Clean Water Act, states, territories and tribes receive grant money that supports a...
Clean Water State Revolving Fund Program1. Each State’s clean water state revolving fund program authorized under Title VI of the Clean Water Act, as...
Clean Watersheds Needs Survey IDA unique identifier for a facility. Most facilities identified are publicly owned treatment works (POTWs)...
Clean wood1. Untreated wood or untreated wood products including clean untreated lumber, tree stumps (whole or...
Cleaner production assessmentA methodology to systematically identify and evaluate cleaner (less polluting, less toxic and less wasteful)...
Cleaner technologies substitutes assessmentA document that systematically evaluates the relative risk, performance, and cost trade-offs of technological...
Clean-fuel vehicle aftermarket conversion certifierBusiness or entity that obtains a certificate of conformity with the clean-fuel vehicle standards and...
CleaningThe process of removing unwanted substances and putting them in their proper place.
Cleaning material1. Solvent used to remove contaminants and other materials such as dirt, grease, oil, and dried (e.g...
Cleaning operation1. Operations in which organic HAP solvent is used to remove coating materials or adhesives from equipment...
Cleaning productConsumer use product such as soaps and detergents used to make surfaces free from dirt, germs, or stains.
Cleaning product additiveA substance added to a cleaning product, often to make the product smell more acceptable.
Cleaning solventLiquid material used for hand-wipe, spray gun, or flush cleaning. This definition does not include solutions...
Cleaning verification cardCard developed and distributed, or otherwise approved, by EPA for the purpose of determining, through...
Cleaning waterProcess water used to clean the surface of an intermediate or final plastic product or to clean the surfaces...
CleanoutMethods to remove solids or debris.
Cleanup1. Actions taken to deal with a release or threat of release of a hazardous substance that could affect...
Cleanup activities, see Cleanup activity
Cleanup activityCleanup activity at a site include removals, studies, remedy selection, remedy design, remedy implementation...
Cleanup and remediation1. Cleanup: Actions taken to deal with a release or threat of release of a hazardous substance that could...
Cleanup complete1. All the cleanup objectives have been met, media cleanup is final, all the sources of releases are...
Cleanup cost liabilityUnder Superfund, a party responsible for the presence of hazardous waste at a site is also legally...
Cleanup enforcementCleanup enforcement gets property cleaned up by finding the companies or persons responsible for...
Clean-up GoalsA set of clean-up target levels to be attained for specific contaminants when cleaning up the site.
Cleanup jobs leveragedThe total number of cleanup jobs leveraged during the cleanup at the property. This number includes...
Clean-up OperationA clean-up operation is where hazardous substances are removed, contained, incinerated, neutralized...
Cleanup outcomeAdditional information provided in response to a cleanup action that is underway or completed. Outcomes can...
Cleanup planningCleanup Planning Activities are completed when the grant recipient accepts the completed one or more cleanup...
Cleanup processesActions taken to deal with a release or threat of release of a hazardous substance that could affect humans...
Cleanup site1. Sites where oil or hazardous chemicals have been released into the environment or when there is a threat...
Cleanup site identificationThe site has been identified for cleanup after being investigated to determine the nature and extent of...
Cleanup sites, see Cleanup site
Cleanup Solution is ImplementedThe State or EPA has acknowledged, in writing, that the RCRA site/facility has completed construction of a...
Cleanup technologiesMechanical and scientific tools used to assess, accomplish, and monitor the cleanup of hazardous wastes
Clean-up TechnologyTechnology used to clean up a spill or release after it happens.
Cleanup time frameThe cleanup time frame, with respect to groundwater, is an estimate of when groundwater quality will achieve...
Cleanup time frames, see Cleanup time frame
Clear coating1. Coating allowing light to pass through, so that the substrate may be distinctly seen.
Clear cut1. Harvesting all the trees in one area at one time, a practice that destroys vital habitat and biodiversity...
Clear cutting1. A forest-management technique that involves harvesting all the trees in one area at one time.
Clear high-alkalinity lakeLake with long-term color less than or equal to 40 Platinum Cobalt Units (PCU) and Alkalinity greater than 20...
Clear low-alkalinity lakeLake with long-term color less than or equal to 40 PCU and alkalinity less than or equal to 20 mg/L CaCO3.
Clear substanceAllowing light to pass through, so that the substrate may be distinctly seen.
Clear well1. A reservoir for the storage of filtered water of sufficient capacity to prevent the need to vary the...
ClearanceThe process for obtaining line management approvals prior to a work product’s external release or publication.
Clearance kineticsRate of clearance of substance metabolites as measured in unit time. Elimination occurs as a result of...
Clearance levelValues that indicate the amount of lead in dust on a surface following completion of an abatement activity...
Clearance/Excretion KineticsRate of clearance of substance metabolites as measured in unit time. Elimination occurs as a result of...
Clearcutting1. A silvicultural system in which all merchantable trees are harvested within a specified area in one...
Cleared reviewsOPP Science Reviews may contain information that registrants may claim as confidential, many times they must...
Clearest dayThe twenty percent of monitored days in a calendar year with the lowest values of the deciview index.
Clearing sawSometimes known as brush cutters, saws made for individual use for clearing small trees, brush and shrubbery.
ClerksWhen cargo is unloaded from a ship, a clerk checks the actual count of the goods versus the amount listed on...
Client/ServerA distributed model of interaction in which a single application services requests from one or more other...
Client-side image mapsAn image map is a graphic image defined so that a user can click on different areas of the image and be...
Cliff1. Very steep or vertical slope.
Climate1. Average of day-to-day weather conditions at a given place on earth over a fairly long period, usually 30...
Climate action planConsists of an assessment of greenhouse gas emissions through an inventory and provides a set of strategies...
Climate adaptationAdaptation of people and their societies to the climate in which they live
Climate air quality interactionClimate and air quality are closely coupled..... conventional pollutants, such as ozone and particle...
Climate anomalyThe deviation of a measurable unit, (e.g., temperature or precipitation) in a given region over a specified...
Climate Change1. This term is commonly used interchangeably with "global warming" and "the greenhouse effect," but is a...
Climate change action planA climate change action plan is a comprehensive document that outlines a state's response to climate change...
Climate change adaptation1. Taking actions to avoid, benefit from, or deal with current and future climate change. Adaptation can take...
Climate change impactThe direct environmental effects of climate change that might be addressed in a RAINE plan or product.
Climate change refugiumArea relatively buffered from contemporary climate change that is likely to increase species or ecosystem...
Climate feedback1. A process that acts to amplify or reduce direct warming or cooling effects.
Climate feedback mechanismFeedback is an enhancement (positive feedback) or a damping (negative feedback) of an initial change. in this...
Climate forcing aerosolAnthropogenic aerosols create a significant perturbation in the earth's radiative balance on regional scales...
Climate forcing gasAlso known as greenhouse gas. Any gas that absorbs infrared radiation in the atmosphere. Greenhouse gases...
Climate lag1. The delay that occurs in climate change as a result of some factor that changes only very slowly. For...
Climate model1. A series of calculations run on a computer that simulates how the atmosphere, oceans, land, living things...
Climate outlookGives probabilities that conditions. averaged over a specified period will be below normal, normal, or above...
Climate sensitivity1. In Intergovernmental Panel on Climate Change (IPCC) reports, equilibrium climate sensitivity refers to the...
Climate signalA statistically significant difference between the control and disturbed (see climate sensitivity)...
Climate system1. The five physical components (atmosphere, hydrosphere, cryosphere, lithosphere, and biosphere) that are...
Climate variabilityThe range of values the climate at a particular location can take over time. Example: Although the average...
Climate-induced disasterSevere, increasingly frequent, widespread and costly disasters such as extreme heat, drought and wildfires...
Climatological outlookAn outlook based upon climatological statistics for a region, abbreviated as CL on seasonal outlook maps. CL...
Climatology1. Description and scientific study of climate.
Climax communityThe kind of biotic community capable of self perpetuation under the prevailing climatic and soil conditions...
Clinger richnessA metric used to measure the diversity of macroinvertebrates that have the ability to attach to the substrate...
ClinicalSymptoms are present, supportive therapy or treatment is necessary.
Clinical measurementA figure, extent, or amount obtained by measuring made for the immediate purpose of treating or observing...
Clinical studiesStudies of humans suffering from symptoms induced by chemical exposure.
Clinical toxicity measurementMeasures of the degree to which a substance or mixture of substances can harm humans or animals.
Clinical trial1. Research study conducted with patients, usually to evaluate a new treatment or drug. Each trial is...
ClinkerProduct of a cement kiln from which finished cement is manufactured by milling and grinding.
CloacaA common passage for the fecal, urinary, and reproductive discharges of most lower vertebrates (birds...
ClofibrateA fibric acid derivative used in the treatment of hyperlipoproteinemia type III and severe...
Clonal evolutionThe process by which a normal cell accumulates genetic changes that allow it to become a tumor-causing cell...
Clonal expansionMultiplication or reproduction by cell division of a population of identical cells descended from a single...
ClonazepamAn anticonvulsant used for several types of seizures, including myotonic or atonic seizures, photosensitive...
Clone1. An identical copy of a DNA sequence or entire gene; one or more cells derived from and identical to a...
ClonicPertaining to alternate muscular contraction and relaxation in rapid succession
CloningIn biotechnology, obtaining a group of genetically identical cells from a single cell; making identical...
Cloning vector1. Any DNA molecule capable of autonomous replication within a host cell and into which other DNA sequences...
Close out reportA report submitted by the remedial program manager (RPM) verifying that the conditions of the site comply...
Closed areaSeparately lined area of an MSW landfill in which solid waste is no longer being placed. If additional solid...
Closed biological treatment process1. Tank or surface impoundment where biological treatment occurs and air emissions from the treatment process...
Closed blowdown systemSystem used for depressuring process vessels that is not open to the atmosphere and is configured of piping...
Closed captioningA service for persons with hearing disabilities that translates television program dialog into written words...
Closed circulatory systemA circulatory system in which blood flows through blood vessels at all times. Blood flows from arteries to...
Closed cooling water systemAny configuration of equipment in which heat is transferred by circulating water that is contained within the...
Closed course competition eventAny organized competition event covering an enclosed, repeated or confined route intended for easy viewing of...
Closed cycleThese systems use fluid with a low-boiling point, such as ammonia, to rotate a turbine to generate...
Closed file1. A file unit or series containing documents on which action has been completed and to which more documents...
Closed fisheryA fishery closed or restricted by a government entity. Such closure prohibits fishing for commercial...
Closed landfill1. Landfill in which solid waste is no longer being placed, and in which no additional solid wastes will be...
Closed portionThat portion of a facility which an owner or operator has closed in accordance with the approved facility...
Closed questionA question with more than one possible answer from which one or more answers must be selected.
Closed systemThis means that energy or mass cannot either leave or enter the system from an environment external to the...
Closed system for flushing fixed linesSystem in which the line to be flushed is disconnected from its original position and connected to two closed...
Closed vent system shutdownWork practice or operational procedure that stops production from a process unit or part of a process unit...
Closed-cell foamAny foam product, excluding packaging foam, that is constructed with a closed-cell structure and a blowing...
Closed-cycle depainting systemDust-free, automated process that removes permanent coating in small sections at a time and maintains a...
Closed-cycle recirculating systemSystem designed, using minimized makeup and blowdown flows, to withdraw water from a natural or other water...
Closed-ended questionsA question that limits responses to predetermined categories.
Closed-loop geothermal heat pumpClosed-loop (also known as "indirect") systems circulate a solution of water and antifreeze through a series...
Closed-loop ProductionA production system in which any industrial output is capable of being recycled to create another product.
Closed-loop pumped storage hydropowerProjects typically consisting of two reservoirs that are not connected to naturally-flowing sources of water.
Closed-loop recycling1. Reclaiming or reusing wastewater for non-potable purposes in an enclosed process.
Closed-loop system1. Enclosed system that returns process fluid to the process.
Closed-purge system1. System or combination of systems and portable containers to capture purged liquids. Containers for purged...
Closed-top cupolaCupola that operates as a closed (process) system and has a restricted air flow rate.
Closed-top hopperCompletely enclosed storage vessel used to transport dry bulk cargos, either by truck, rail, or barge...
Closed-vent system1. System that is not open to the atmosphere and is composed of piping, ductwork, connections, and, if...
Close-grown cropCrops that are generally drill-seeded or broadcast, such as wheat, oats, rice, barley, and flax.
CLOSEOUT1. The process by which a Federal awarding agency determines that all applicable administrative actions and...
CLOSEOUT MEMOThe Project Officer's memo which documents their review of the recipient's Financial status report against...
Closing revolutions per minuteEngine speed in Figure 2 of Appendix I.
ClostridiumA genus of motile or nonmotile gram-positive bacteria of the family Clostridiaceae. Many species have been...
Clostridium botulinumThe name of a group of bacteria commonly found in soil. These rod-shaped organisms grow best in low oxygen...
Clostridium chauvoeiA species of gram-positive bacteria in the family Clostridiaceae isolated from infected CATTLE; SHEEP; and...
Clostridium perfringens1. An anaerobic, Gram-positive, sporeforming rod (anaerobic means unable to grow in the presence of free...
Clostridium septicumA species of gram-positive bacteria in the family Clostridiaceae. Infections have a strong association with...
Closure1. The procedure an operator must go through when a landfill reaches the legal capacity for solid waste. No...
Closure deviceCap, hatch, lid, plug, seal, valve, or other type of fitting that, when the device is secured in the closed...
Closure planPlan required under §264.112 of this chapter.
Clothes washerProduct designed to clean clothes, utilizing a water solution of soap and/or detergent and mechanical...
ClothianidinA neonicotinoid insecticide which acts on the insect central nervous system. Less toxic to mammals than some...
Cloud characteristicHow the cloud capabilities are provided
Cloud chemistryChemical changes that happen in clouds.
Cloud classificationCollections of water (in liquid or ice phase) in the atmosphere that are often classified by their shape and...
Cloud computing1. A technology that allows users to access and use shared data and computing services via the Internet or a...
Cloud condensation nucleus1. A particle, either liquid or solid, upon which water condenses to form cloud droplets.
Cloud deployment modelHow the cloud infrastructure can be positioned
Cloud droplet activationPoint at which water vapor condenses on ambient aerosol particles to form a droplet.
Cloud feedbackThe coupling between cloudiness and surface air temperature in which a change in surface temperature could...
Cloud forcingThe difference between the radiation budget components for average cloud conditions and cloud-free...
Cloud infrastructureA cloud infrastructure is the collection of hardware and software that enables the five essential...
Cloud microphysicsAtmospheric physical processes on a micro-scale that affect the creation, development and precipitation in...
Cloud microstructureAs characterized by the droplet size spectrum, the liquid water content, and cloud droplet concentration
Cloud produced particleWhen gas molecules unite to form an aerosol particle
Cloud service modelThe types of capabilities inherent in cloud computing
ClumStem of a grass plant.
Cluster1. A cluster is a set of Revision Checklists developed for federal rules promulgated between a specified...
Cluster analysisA set of statistical methods used to group variables or observations into strongly inter-related subgroups...
Cluster investigationA review of an unusual number, real or perceived, of health events (for example, reports of cancer) grouped...
Cluster sampleA probability sample for which groups or geographic areas comprising groups were randomly selected.
Cluster samplingIf natural groups exist in a population, they can be divided into clusters and all the clusters are randomly...
Cluster system1. A wastewater collection and treatment system under some form of common ownership that collects wastewater...
Cluster treatment systemA wastewater treatment system designed to serve two or more sewage-generating dwellings or facilities with...
Clustered data1. Measurements collected on some grouping of individuals, e.g., litters in reproductive and developmental...
Clustered development1. Accumulation of development onto only a portion of a site, thereby allowing sensitive areas to be...
ClusteringIdentifying similar characteristics and grouping samples with similar characteristics together.
ClutchA group of eggs laid together at one time.
C-MetaphaseState of arrested cell growth typically seen after treatment with a spindle inhibitor, i.e., colchicine.
CMI workplan approvedThe event by which the State or EPA approves the Corrective Measure Implementation Plan.
CMS completeThe event by which the State or EPA determines the CMS to be sufficient to support a Remedy Decision.
CMS implementation begunThe event by which a RCRA facility committed to any implementation in its agency approved CMS Workplan.
CMS impositionThe event by which the State or EPA formally imposes the obligation upon a RCRA facility to perform a...
CMS progress reports receivedReceipt of reports submitted by the RCRA facility to State or EPA during execution of the approved CMS...
CMS report receivedThe event by which a RCRA facility submits a written summary of the results of the approved CMS workplan.
CMS supplemental information deemed satisfactoryThe event by which the State or EPA approves the CMS supplemental information.
CMS supplemental information receivedThe event by which the RCRA facility submits an amendment, modification, clarification, or other supplemental...
CMS supplemental information requested by agencyThe event by which the State or EPA requests the RCRA facility to modify, amend, revisit, reexamine, or...
CMS workplan approvedThe event by which the State or EPA approves the CMS plan submitted by the RCRA facility.
CMS workplan modification requested by agencyThe event by which the State or EPA requests that the RCRA facility modify its CMS workplan.
CMS workplan receivedThe event by which a RCRA facility submits a CMS workplan to the State or EPA.
CnidariaA multicellular animal phylum, with a tissue grade of construction, that contains the stony (hard) corals...
Cnidarian body partSpecialized body parts of jellyfish, corals, and other stingers
CO2 emission rateFor a designated facility, the reported CO2 emission rate of a designated facility used by a designated...
Coagulant aidAny chemical or substance used to assist or modify coagulation.
Coagulants(co-AGG-you-lents) Chemicals that cause very fine particles to clump together into larger particles. This...
Coagulation1. (co-AGG-yoo-LAY-shun) The clumping together of very fine particles into larger particles caused by the use...
Coagulation-assisted micro-filtrationA treatment process by which the physical or chemical properties of dissolved colloidal or suspended matter...
Coagulation/Filtration TechnologyCoagulation and filtration is one of the most common water treatment techniques used by larger water systems...
Coagulation/FlocculationRemoval of solids deposited by sedimentation in a non-reactive system where physical "clumping" of solids...
Coal1. Coal is formed from plant and animal matter that has been subjected to geologic heat and pressure...
Coal, anthraciteIt is a hard, brittle, and black lustrous coal, often referred to as hard coal, containing a high percentage...
Coal ashCoal combustion residuals (CCRs), commonly known as coal ash, are byproducts of the combustion of coal at...
Coal ash pondCoal ash is generated from the burning of coal at power plants and is disposed of in large ponds called...
Coal bed1. A bed or stratum of coal. Also called a coal seam.
Coal, bituminousA dense coal, usually black, sometimes dark brown, often with well-defined bands of bright and dull material...
Coal cleaning technologyA precombustion process by which coal is physically or chemically treated to remove some of its sulfur so as...
Coal cokeA hard, porous product made from baking bituminous coal in ovens at temperatures as high as 2,000 degrees...
Coal combustion emissionEmission caused by the burning of coal. The burning needed to generate energy releases carbon dioxide, water...
Coal combustion permanent cessationOwner or operator certifies under § 423.19(f) that an electric generating unit will cease combustion of coal...
Coal combustion permanent cessation certificationOwner or operator certifies under § 423.19(g) or (h) that an electric generating unit will cease combustion...
Coal combustion residuals landfillArea of land or an excavation that contains CCR and which is not a surface impoundment, an underground...
Coal combustion residuals surface impoundmentNatural topographic depression, man-made excavation, or diked area, designed to hold an accumulation of CCR...
Coal combustion residuals unitCCR landfill, CCR surface impoundment, or lateral expansion of a CCR landfill or CCR surface impoundment, or...
Coal combustion residueResidue, such as fly ash, bottom ash, and boiler slag, from the burning of coal.
Coal extraction1. The physical removal or exposure of ore, coal, minerals, waste rock, or overburden prior to beneficiation...
Coal fired unit1. Except for purposes of subpart EE of this part, combusting any amount of coal or coal-derived fuel, alone...
Coal fly ashA by-product of coal burning at electricity plants. It is called "fly" ash because it is transported from the...
Coal (Fuel), see Coal
Coal gasification1. Conversion of coal to a gaseous product by one of several available technologies.
Coal hypothetical resourceUndiscovered coal resources in beds that may reasonably be expected to exist in known mining districts under...
Coal, ligniteOften referred to as brown coal, used almost exclusively as fuel for steam-electric power generation. It is...
Coal liquefactionConversion of solid coal to a liquid fuel such as synthetic crude oil or methanol.
Coal mine1. An opening or excavation in the earth for the purpose of extracting (coal).
Coal mine emissionEmission of methane formed by the decomposition of organic matter, it is the most common gas found in coal...
Coal mine methane1. Coal mine methane is the subset of coalbed methane that is released from the coal seams during the process...
Coal miningThis industry comprises establishments primarily engaged in one or more of the following: (1) mining...
Coal pile runoffRainfall runoff from or through any coal storage pile.
Coal power plantAn electricity generation plant which uses coal as its fuel
Coal preparation and processing plantAny facility (excluding underground mining operations) which prepares coal by one or more of the following...

3,254 of 29,894 terms in Environment terminology (MLC-0121). Request the full dataset.