Glossary of Environmental Cleanup Terms
This glossary lists common terms related to New York State Department of Environmental Conservation's voluntary cleanup, brownfield, and inactive hazardous waste disposal site programs. It includes some terms used by the United States Environmental Protection Agency's (EPA) Superfund program. Glossary explanations should help you understand various environmental concepts. Some words within the definitions are in bold, which indicates that they are defined elsewhere in the glossary.
The definitions in this glossary do not constitute the state's official use of terms and phrases for regulatory purposes, and nothing in this document should be construed to alter or supplant any other state document. The glossary includes brief definitions of some contaminants frequently found at hazardous waste sites. However, not all contaminants found at hazardous waste sites are included, nor are the listed contaminants found at every site.
- Chemicals that have a high concentration of hydrogen ions. Acids have a pH of less than 7 on a scale of 0 to 14. Strong acids, closer to 0 on the scale are corrosive, and weak acids, with a pH closer to 7, are not. An acid is the opposite of a base.
- A highly absorbent form of carbon, formed primarily from coal and lignite, that absorbs organic compounds. "Activated carbon treatment systems" are used to remove odors and toxic substances from liquid or gaseous emissions.
- Health effects that have a rapid onset, a short course, and pronounced symptoms and termination. A reaction that occurs shortly after exposure to a chemical.
- A single, short contact with a chemical. It may last a few seconds or a few hours, but no longer than a day.
Administrative order on consent
- See Consent order
- Part of a site's Record of Decision (ROD) which lists and defines documents used in the development of DEC's decision about selection of a remedial action.
- Molecules of gas, liquid, or dissolved solids that adhere or "stick" to the surfaces they come in contact with. Some chemicals adsorb strongly to soil particles. This differs from absorb: "to take up or make part of the existing whole," like a sponge absorbs (sucks up) water.
- Injecting air or oxygen into an aquifer to strip or flush volatile contaminants as air bubbles up through the ground water. The air is captured by a vapor extraction system. (See soil vapor extraction system).
- A treatment system that removes or "strips" volatile organic compounds from contaminated groundwater or surface water by forcing an airstream through the water and causing the compounds to evaporate.
- The surrounding environment. Ambient usually refers to the surrounding outdoor air, water, or land.
- Absence of oxygen. Some organisms, such as certain soil bacteria, thrive under anaerobic conditions in soil.
- A chemical being tested for in a laboratory test.
- An element used in wood preservatives and pesticides.
Applicable or Relevant and Appropriate Requirements (ARARs)
- Any state or federal statute that pertains to protection of human life and the environment in addressing specific conditions or use of a particular cleanup technology at a Superfund site.
- An underground water-bearing formation of soil or rock commonly used for drinking water.
- See Recharge
- Geological formation that may contain groundwater but significant quantities of water will not move through it under normal conditions. May function as a confining layer.
Area of Concern or "AOC"
- Any existing or former location at a site where contaminants are known or suspected to have been discharged which is considered a source area. These include locations where contaminants were generated, manufactured, refined, transported, stored, handled, treated, disposed or where they have or may have migrated.
- A scheduled gathering of program staff and members of the public in a casual setting, with or without a formal presentation or agenda but usually focusing on a specific aspect of a site's remedial process.
Background, Background level
- The concentration of a substance in air, water, or soil that occurs naturally or is the result of human activities not related to a hazardous waste site; conditions in the area near, but not affected by, a hazardous waste site. "Background samples" are often taken to compare an area's natural or pre-existing conditions to conditions at a hazardous waste site.
Barrier protection layer
- A layer of soil covering a geomembrane designed to protect the geomembrane from wear and tear caused by the weather, animals, etc.
- Bases are chemicals that have a large concentration of hydroxyl (one hydrogen plus one oxygen atom) ions. A basic compound has a pH of more than 7 on a scale of 0 to 14. Strong bases, pH closer to 14, are corrosive. Weak bases, with pH closer to 7, are not. An acid can neutralize the effects of a base.
- The continuous solid rock of the continental crust. Bedrock can be found anywhere from the surface to hundreds of feet below ground. Bedrock can be solid or it can contain numerous cracks (fractures). Groundwater and chemicals can move through fractured bedrock.
- bottom-dwelling; usually refers to aquatic life living at the bottom of a river, stream or lake.
- A very fine clay, expansible when moist, commonly used to provide a tight seal around a monitoring well. Also used in slurry walls.
- The build-up of toxic materials in body tissues of fish and animals.
- The extent to which a substance can readily be absorbed by an organism or is ready to interact in an organism's metabolism.
- The degradation (breakdown) or stabilization of contaminants in the environment by microorganisms. There are many remedial techniques that use microorganisms, such as bacteria, to break down contaminants. Any of these techniques may be called bioremediation.
- All the living organisms in a given area.
- Hole made with drilling equipment.
- See Soil boring
- Any real property, the redevelopment or reuse of which may be complicated by the presence or potential presence of a contaminant. A contaminant may be hazardous waste and/or petroleum. Brownfield sites can pose environmental, legal, and financial burdens on a community and its taxpayers.
- A process by which contaminants are removed from groundwater or surface water when the water is forced through tanks containing activated carbon, a material that attracts the contaminants.
- A colorless, nonflammable liquid with a characteristic odor used as a solvent and in the synthesis of fluorocarbons.
- A cancer-producing substance.
Catch basin or catch-basin
- A structure used to catch sediments for contaminant retention, often on a stream.
- A cistern or vault at the point where a pipe from inside a factory or a street gutter discharges into a sewer, to catch bulky matters which would not pass readily through the sewer.
- Capable of producing or inciting cancer.
- Chemicals containing only chlorine, carbon, and hydrogen. These include some pesticides, such as DDT and heptachlor, and solvents such as trichloroethene and chloroform.
- A group of organic (carbon-containing) solvents which contain chlorine as a part of their molecular structure. Chlorinated solvents are widely used for metal parts cleaning, dry cleaning, chemical processing, and photographic film making. Common chlorinated solvents include chloroform, methylene chloride, carbon tetrachloride, trichloroethene, tetrachloroethene, and 1,1,1-trichloroethane.
- A clear, colorless liquid with a characteristic odor. Chloroform was one of the earliest general anesthetics but this use was abandoned due to toxic effects. Now it is widely used as a solvent in the production of lacquer, pharmaceuticals, fluorocarbons, and plastics.
- A long-term or repeated reaction that occurs after an exposure to a chemical. Chronic effects are the opposite of acute effects.
Citizen participation (CP)
- A process to inform and involve citizens in the decision-making process during identification, assessment and remediation of inactive hazardous waste sites. This process helps to assure that sound decisions are made from environmental, human health, economic, social and political perspectives.
Citizen participation plan
- A document that describes the site-specific citizen participation activities that will take place to complement the investigation and clean-up activities at a hazardous waste site. A plan may be updated or altered as public interest or the technical aspects of the program change.
Citizen participation record
- A series of documents prepared at a major remedial stage which describes the citizen participation activities required at that stage. A CP record also directs a scoping process to determine if additional citizen participation activities are appropriate and feasible.
Citizen participation specialist
- A DEC staff member within the Office of Communication Services who provides guidance, evaluation and assistance to help the project manager carry out the site-specific citizen participation program.
- Action taken to respond to a hazardous material release or threat of a release that could affect humans and/or the environment. Also called remedial action, removal action, response action, or corrective action.
- A time period for the public to review and comment on various documents and Division of Environmental Remediation (DER) actions. For example, a 30 day comment period is provided when DER issues a Proposed Remedial Action Plan (PRAP).
- The Environmental Protection Agency's program to inform and involve the public in the Superfund process and respond to community concerns.
Community relations plan (CRP)
- The formal plan for Environmental Protection Agency community relations activities at a Superfund site. The CRP is designed to ensure citizen opportunities for public involvement and allow citizens the opportunity to learn about a site.
Comprehensive Environmental Response, Compensation, and Liability Act of 1980 (CERCLA)
- A Federal law passed in 1980 and modified in 1986 by the Superfund Amendments and Reauthorization Act. CERCLA created a special tax that goes into a trust fund, commonly known as Superfund, to investigate and clean up abandoned or uncontrolled hazardous waste sites. Under the pro-gram, EPA can either pay for site cleanup when parties responsible for the contamination cannot be located or are unwilling or unable to perform the work; or take legal action to force parties responsible for site contamination to clean up the site or reimburse the government for the cost of cleanup.
Cone of depression/Cone of influence
- A depression in the water table that develops around a pumped well.
- The amount of one substance in another substance. For example, a concentration of 10 milligrams per liter means there are 10 milligrams of a substance in 1 liter of another substance.
- The general outline of planned actions that will be taken to address a hazardous waste site, such as building a landfill cover system. The conceptual design is incorporated into detailed design documents during Remedial Design.
Confining layer (confining bed)
- A layer or bed of impermeable or distinctly less permeable material lying below or above one or more aquifers. When the confining layer lies between two aquifers, it keeps water from the upper aquifer separated, or confined, from water in the lower aquifer.
- A legal and enforceable negotiated agreement between DEC and responsible parties where responsible parties agree to undertake investigation and cleanup or pay for the costs of investigation and cleanup work at a site. Also called an "Order on Consent."
Construction and demolition (C&D) debris/ waste
- Waste building materials, dredging materials, tree stumps, and rubble resulting from construction, remodeling, repair, and demolition of homes, commercial buildings and other structures and pavements.
- Names, addresses emails, and/or telephone numbers of individuals, groups, organizations and media interested and/or affected by a particular hazardous waste site.
- Hazardous waste and/or petroleum as such terms are defined in 6 NYCRR 375-1.2(g)
- The presence of a contaminant in any environmental media, including soil, surface water, sediment, groundwater, soil vapor, ambient air or indoor air.
- The volume and area of contaminants in a polluted material, such as soil or groundwater. The goal of waste cleanup is to reduce the contaminant mass (e.g., reduce the amount and area of contaminants in soil).
- see Plume
Contract Laboratory Program (CLP)
- The Environmental Protection Agency's program that approves laboratories that provide chemical testing services of known quality using a wide range of standard methods and maintaining consistent quality control.
- Having the power to degrade or wear away a material by chemical action.
- A legal process where potentially responsible parties can be required to pay back the federal or state government for money spent on cleanup actions. Cost recovery actions usually begin after the government has completed a site cleanup.
- Soil used to cover compacted solid waste in a sanitary landfill.
- A notice placed on a property deed to alert future buyers about contamination on a property.
- An encumbrance on a property that controls the use of the property. The restriction runs with the land in favor of the State and contains the use restriction(s) and/or prohibition(s) on the use of land in a manner inconsistent with engineering controls.
Degradation products (Daughter products)
- Chlorinated solvents, when released in the environment, will naturally degrade by microbial and physical processes in soil and/or groundwater into similar compounds that have fewer chlorine atoms. These new compounds are known as degradation products. For instance, tetrachloroethylene, which has 4 chlorine atoms, degrades to trichloroethylene, which has only 3 chloride atoms.
- Chemical used to remove grease, usually from metal or plastic.
Dense Non-Aqueous Phase Liquid(DNAPL)
- Liquids denser than water that represent a special class of soil and groundwater contaminants with unique behavior and problems. Since they are denser than water, DNAPLs can sink deeper into the ground and can act as a continuing source of groundwater contamination, as small amounts of the material can dissolve in groundwater.
- The mass of a substance per unit of volume. Substances with a density greater than 1.0 are denser than water; substances with a density less than 1.0 are lighter than water.
- By or through the skin. "Dermal contact" refers to a substance coming in contact with skin.
- The opposite of adsorption or absorption; molecules detach from a surface (such as soil particles).
- The lowest concentration of a chemical that can be reliably measured by a testing method.
- Remove a portion of the water in soil or sludge to dry the soil/ sludge so it can be treated or disposed of.
Remove or drain the water from a tank or trench.
1,1-Dichloroethane (1,1-DCA) and 1,2-Dichloroethane (1,2-DCA)
- Chemicals with similar molecular structures used to produce a variety of consumer and industrial products, such as specialty chemicals and cleaning products. These chemicals are sometime found at hazardous waste sites as the degradation products of other chemicals, such as trichloroethane.
Dichloroethene (DCE) or 1,1-Dichloroethene and 1,2-Dichloroethene
- Chemicals with similar molecular structures used to make specialty chemicals and pharmaceuticals. These chemicals are sometimes found at hazardous waste sites as the degradation products of trichloroethene.
- Movement of a substance from an area of high concentration to an area of low concentration. Diffusion can also refer molecules of gas or vapor moving from a source, such as a bottle, to a receptor, such as a human nose.
Division of Environmental Remediation
- A major unit within the DEC created to manage the hazardous waste site remedial program from site discovery through Operation and Maintenance activities. Staff include: engineers, geologists, chemists, attorneys, citizen participation specialists, environmental program specialists and support staff.
- Typically, a DEC regional office and/or a public building, such as a library, near a particular site, at which documents related to remedial and citizen participation activities at the site are available for public review. The public can also receive site information via email by signing up through the GovDelivery service.
- The direction that groundwater flows; similar to "downstream" for surface water.
- See Swale
- The vertical drop in the height between the water level in a well prior to pumping, and the water level in the well during pumping.
- A metal or plastic container, usually with a 55 gallon capacity.
- A hole dug to a depth above the water table so that its bottom and sides are typically dry except when receiving fluid discharged from an industrial process. Is often filled with gravel or is reinforced with concrete blocks to form a chamber.
Dual-Phase Vacuum Extraction System
- A treatment system designed to remove both contaminated groundwater and soil gas from a common groundwater well or wells. By removing ground-water, the system lowers the groundwater level around the well, allowing a strong vacuum to be applied to remove contaminated soil gas. The contaminated water and air can then be removed or treated and released.
- A sample taken at the same location as another sample. Both samples are tested for chemicals. Taking a duplicate sample helps to ensure that testing procedures are precise: because the samples were taken in the same location, the samples should contain similar levels of chemicals.
- Treated or untreated wastewater that flows out of a treatment plant, sewer, or industrial outfall. Generally refers to wastes discharged to surface waters.
- DEC's efforts, through legal action if necessary, to compel a responsible party to perform or pay for site remedial activities.
- Any physical barrier or method employed to actively or passively contain, stabilize, or monitor contamination, restrict the movement of contamination to ensure the long-term effectiveness of a remedial program, or eliminate potential exposure pathways to contamination. Engineering controls include, but are not limited to, pavement, caps, covers, subsurface barriers, vapor barriers, slurry walls, building ventilation systems, fences, access controls, provision of alternative water supplies via connection to an existing public water supply, adding treatment technologies to such water supplies, and installing filtration devices on private water supplies.
- An interest in real property, created under and subject to the provisions of ECL Article 71, Title 36 which contains a use restriction and/or a prohibition on the use of land in a manner inconsistent with engineering controls, provided that no such easement shall be acquired or held by the state which is subject to the provisions of article 14 of the constitution of the State of New York.
Environmental Notice Bulletin
- A weekly DEC publication used to announce a variety of DEC activities. The ENB announces proposals to delist or change the site classification of hazardous waste sites, as well as voluntary cleanup agreements.
- The study of diseases as they affect population, including the distribution of disease, the factors (e.g., age, sex, occupation) that influences this distribution; and the application of this study to control health problems.
EP Tox Test
Explanation of Significant Differences (ESD)
- A document prepared by the Division of Environmental Remediation explaining changes to a cleanup plan called for in a Record of Decision and the reason for those changes.
- The amounts of vapor in air which form explosive mixtures. Explosive limits are expressed as "lower explosive limits" and "upper explosive limits;" these give the range of vapor concentrations in air that will explode if heat is added. Explosive limits are expressed as percent of vapor in air.
- Contact. No matter how dangerous a substance or activity, without exposure, it cannot harm you.
- A means by which a toxic substance can come into contact with or enter the body. The three major exposure routes are: inhalation (breathing), direct contact (touching), and ingestion (swallowing).
- Outside the original location. For example, contaminated that soil is dug up and removed before it is treated is being treated ex-situ. This is the opposite of in-situ.
- Violation of the pollutant levels permitted by environmental protection standards.
Extraction procedure (EP Tox Test)
- Determining toxicity by a procedure which simulates leaching; if a certain concentration of a toxic substance can be leached from a waste, that waste is considered hazardous, i.e., "EP Toxic."
- A discharge well used to remove contaminated groundwater or air.
Feasibility Study (FS)
- A report examining the pros and cons of alternative methods to address contamination at a hazardous waste site. The feasibility study usually recommends a certain alternative. The FS is usually based on the results of a remedial investigation; together, they are commonly referred to as the RI/FS.
- A weekly publication covering federal government activity including rule making, proposed plans, response to public comments, etc..
- Man-made deposits of natural soils or rock products and waste materials.
Final Engineering Report (FER)
- A report prepared to document implementation of the complete remedial program, including the necessary certifications for it. The scope of the FER will vary to reflect the manner in which the remedial program was implemented for the entire site.
Fish and wildlife impact analysis
- Part of a remedial investigation that looks at the effects or potential effects of contamination on fish and wildlife.
- Catches on fire easily and burns rapidly.
- The lowest temperature at which the vapor of a substance will catch on fire, even momentarily, if heat is applied. Provides an indication of how flammable a substance is.
Gas venting system
- A system of pipes and vents installed in a landfill to prevent the build up of landfill gases, such as methane, that could potentially explode. Sometimes the gas vents have flares on them to burn the gas as it is released into the atmosphere. At some very large landfills, the gas is collected and used to generate electricity.
- A low permeability plastic sheet that is placed over a landfill to deter rain and snow from entering a landfill's waste. Geomembranes are often made from a plastic called HDPE (high density polyurethane). The geomembrane is covered with soil (barrier protection layer) and top soil to protect it.
- Techniques used to characterize the subsurface without having to dig up large areas. Examples include seismic refraction (commonly used to determine depth to bedrock), ground-penetrating radar (used to define sub-surface structures and buried objects), and magnetometry (used to detect buried iron objects).
- A special machine used to make soil borings and to create temporary groundwater monitoring wells.
- The unit of mass in the metric system. An ounce is about 28 grams, and a pound is approximately 450 grams.
- A filtering system often used in small water systems and individual homes to remove organic compounds. See activated carbon.
- Water found beneath the earth's surface that fills pores between soil particles such as sand, clay, and gravel or that fills cracks in bedrock. Precipitation that does not evaporate or runoff to surface waters percolates downward through soil and becomes groundwater. Groundwater flows from areas of high elevation to low elevation at generally low velocities (usually ranging from 10-1000 feet/year) and eventually discharges into surface waters such as rivers, lakes, and wetlands. Groundwater often provides a source of drinking water via wells. The chemical composition of the groundwater reflects the soil or bedrock through which it passes; groundwater dissolves minerals in the soil and bedrock. If a source of contamination exists at or below the earth's surface, percolating rainfall or snowmelt can transport contaminants downward where they can migrate with the groundwater.
Groundwater collection/extraction and treatment system
- A system of wells fitted with pumps and piping used to pump out or extract contaminated groundwater from the subsurface. Properly designed and operated systems can effectively contain a groundwater contaminant plume and prevent further contaminant migration.
- See Water Table
- The time required for a pollutant to lose half its effect on the environment.
- The time required for half of the atoms of a radioactive element to undergo decay.
The time required for the elimination of one half a total dose from the body.
- A high-speed machine that uses hammers and cutters to crush, grind, chip, or shred solid waste.
Hazardous ranking system (HRS)
- A scoring system used to evaluate potential relative risks to public health and the environment from releases or threatened releases of hazardous materials. EPA and States use the HRS to calculate a site score (0 to 100) based on the actual or potential release of hazardous materials from a site through air, surface water, or groundwater. This score is the primary factor used to decide if a hazardous waste site should be placed on the National Priorities List.
- A waste which appears on the list or satisfies the characteristics according to ECL 27-0903 and any substance which appears on the list found in ECL 37-0103; provided, however, that the term "hazardous waste" does not include:
- natural gas, natural gas liquids, liquefied natural gas, synthetic gas usable for fuel, or mixtures of natural gas and such synthetic gas; nor
- the residue of emissions from the engine exhaust of a motor vehicle, rolling stock, aircraft, vessel, or pipeline pumping station engine; nor
- source, byproduct, or special nuclear material from a nuclear incident, as those terms are defined in the Atomic Energy Act of 1954; nor
- oil or petroleum of any kind and in any form including but not limited to, oil, petroleum, fuel oil, oil sludge, oil refuse, oil mixed with other wastes and crude oils, gasoline, kerosene and dielectric fluids.
Hazardous waste site
- A place where hazardous wastes have been dumped, buried or improperly stored. Sites range from a crest of land containing thousands of tons of chemical wastes to a few drums of solvents dumped in a vacant lot. See also inactive hazardous waste disposal site.
Health and safety plan
- A plan included in investigation or cleanup work plans which outlines protective measures for site workers and the community during investigation or cleanup activities.
- Anything which can have harmful effects on health. There can be both acute and chronic health hazards.
Health risk assessment
- A process which estimates the likelihood that people who could be exposed to chemicals may have health effects. The four steps of a risk assessment are: (1) hazard identification (Can this substance damage health?), (2) dose-response assessment (What dose causes what effect?), (3) exposure assessment (How and how much do people contact it?), and (4) risk characterization (combining the other three steps to estimate risk).
- Metals with high atomic weights, such as mercury, chromium, cadmium, arsenic, and lead. They can damage living things at low concentrations and tend to accumulate in the food chain.
- A chemical used to control, suppress, or kill plants, or to severely interrupt their normal growth process.
- Consisting of dissimilar ingredients or constituents.
Historic fill material
- Non-native material, historically deposited or disposed in the general area of a site to create useable land by filling water bodies, wetlands or topographic depressions, which is in no way connected with the subsequent operations at the location of the emplacement, and which was contaminated prior to emplacement.
- Having a uniform consistency or ingredients; composed of similar ingredients.
- Operated, moved or effected by means of water.
- The rate at which water can move through a permeable medium.
- In general, the direction of groundwater flow due to changes in the depth of the water table. Just as water flows downhill, water in the ground moves from areas of high elevation to areas of low elevation. The slope of the water table is the hydraulic gradient. The hydraulic gradient determines the speed of groundwater flow. A steep gradient causes groundwater to mover faster than a nearly horizontal gradient.
- Any of a series of chemical compounds that consist entirely of carbon and hydrogen.
Hydrogen Release Compound (HRCTM)
- Hydrogen Release Compound (HRCTM) is a passive treatment option for bioremediation of chlorinated solvents. HRCTM is injected into contaminated soils. Naturally occurring microbes metabolize lactic acid released by HRCTM, and produce hydrogen. The resulting hydrogen can be used to break down the chlorinated solvents. The process requires anaerobic conditions. Major target compounds include perchloroethene, trichloroethene, and trichloroethane as well as their breakdown products.
- Physical tests performed to obtain specific groundwater and geologic data. A pump test, for example, is used to determine the permeability (a measure of how readily groundwater flows) and storage capacity (a measure of the amount of water available) of an aquifer.
- The geology of groundwater, with particular emphasis on the chemistry and movement of water.
- The study of the movement and properties of water on the earth's surface, underground and in the atmosphere.
- Unable to be penetrated, as by liquids. For example, an "impermeable membrane" can be a thin plastic sheet through which rainwater cannot move.
- A hazardous waste site where disposal of hazardous wastes has been confirmed and wastes are no longer being disposed of there ("inactive" site).
- Burning of certain types of solid, liquid, or gaseous materials under controlled conditions to destroy hazardous wastes.
- The penetration of water through the ground surface into sub-surface soil or the penetration of water from the soil into sewer or other pipes through defective joints, connections, or manhole walls. (See: percolation.)
- Water, wastewater, or other liquid flowing into a reservoir, basin, or treatment plant. The opposite of effluent.
- Swallowing. This is one way a person can be exposed to chemicals.
- Breathing. This is one way a person can be exposed to chemicals.
- Chemicals that do not contain carbon. Metals are inorganic chemicals.
- In the original place. In-situ treatment is carried out at a hazardous waste site without having to dig up and move the contaminated material. In-situ is the opposite of ex-situ.
- Incapable of being dissolved in water or another liquid.
- Any non-physical means of enforcing a restriction on the use of real property that limits human or environmental exposure, restricts the use of groundwater, provides notice to potential owners, operators, or members of the public, or prevents actions that would interfere with the effectiveness of a remedial program or with the effectiveness and/or integrity of site management activities at or pertaining to a site.
Interim remedial measure (IRM)
- Action that can be conducted at a site relatively quickly to reduce the risk to people's health and the environment from a well-defined hazardous waste problem. An IRM can involve removing contaminated soil and drums, providing alternative water supplies or securing a site to prevent access.
Land Disposal Restrictions (LDR's)
- Federal rules that require hazardous wastes to be treated before disposal on land to destroy or immobilize hazardous constituents that might migrate into soil and groundwater.
- Any place where wastes were disposed of by dumping waste and covering it.
- There are three main kinds of landfills:
- Sanitary landfills are disposal sites for nonhazardous solid wastes at which the waste is spread in layers, compacted to the smallest practical volume, and covered with material at the end of each operating day.
- Secure chemical landfills are disposal sites for hazardous waste. They are selected and designed to minimize the chance of release of hazardous substances into the environment.
- Old landfills were built without modern day protections; these may contain hazardous wastes. Many of these landfills are being investigated and cleaned up under the State's remediation program.
- A layering of material over a landfill to deter rain and snowmelt from moving through the waste pile. A typical landfill cover will include a geomembrane or a layer of clay covered with a layer of low permeability soil, which in turn is covered by a layer of topsoil and seeded to encourage grass to grow. Landfill cover systems can also include gas vents to prevent gases such as methane from building up inside the landfill. The cover system is designed so rain and snowmelt is directed into a drainage ditch or swale.
- As organic wastes within a landfill break down, gases such as methane and hydrogen sulfide are produced. The production of these gases drops off over time.
- Surface or groundwater that is contaminated while moving through a landfill's wastes.
Leachate collection system
- A system that gathers leachate and pumps it to the surface for treatment.
Light non-aqueous phase liquid (LNAPL)
- Liquids lighter than water that represent a special class of soil and groundwater contaminants with unique behavior and problems. See also NAPL.
- A relatively impermeable barrier designed to keep leachate inside a landfill. Liner materials include plastic and dense clay.
List / listing
- When DEC adds a hazardous waste site to the Registry of Inactive Hazardous Waste Disposal Sites, this is called "listing" a site.
Listservs - Contaminated Sites
- The public can receive site information by email by signing up through the GovDelivery service.
- The unit of volume in the metric system. A liter is about the same as a quart.
Low Temperature Thermal Desorption
- The process of heating soil anywhere between 200 and 1000°F in order to vaporize contaminants with low boiling points. The vaporized contaminants are collected and treated. The low temperatures requires less fuel than other treatment methods.
- A magnetometer is an instrument that can detect metal objects buried underground. When this instrument is used to look for buried drums or other metal objects at a hazardous waste site, this is called a magnetometer survey.
Manufactured Gas Plants (MGPs)
- MGPs were used to produce gas from coal, oil and other fuels but are no longer in operation in New York State. However, coal tar and other hazardous waste, created as part of the manufacturing process, may still be present at those sites and require cleanup.
Maximum contaminant level
- The maximum permissible level of a contaminant in water delivered to any user of a public water system. MCLs are enforceable standards.
- Specific environments that can contain contaminants. Air, water, sediment and soil are media.
- A number of chemical elements that share certain special characteristics. Many metals can be toxic in high doses and can bioaccumulate in the food chain. Metals sometimes found at hazardous waste sites include: arsenic, barium, cadmium, chromium, copper, lead, mercury, nickel, silver, and zinc.
- An odorless gas produced in newer landfills as organic material (previously living things or material derived from living things) breaks down. Methane production drops off as a landfill gets older.
- A colorless nonflammable liquid, with a pleasant aromatic odor, used as a solvent, paint remover, and degreaser.
Micrograms per kilogram (ug/kg)
- A way of expressing dose: micrograms (ug) of a substance per kilogram (kg) of body weight or soil.
Micrograms per liter (ug/l)
- A unit of measure: the number of micrograms of one substance in a liter of liquid. One microgram per liter means one microgram of chemical per liter of water, and is essentially equivalent to one part per billion (ppb). Theoretically one ug/l of a substance equals one part per billion of the substance multiplied by its density.
Milligrams per kilogram (mg/kg)
- A way of expressing dose: milligrams (mg) of a substance per kilogram (kg) of body weight or soil.
Milligrams per liter (mg/l)
- A unit of measure: the number of milligrams of one substance in a liter of liquid. One milligram per liter means one milligram of chemical per liter of water, and is essentially equivalent to one part per million (ppm) at very low concentrations. Theoretically one mg/l of a substance equals one part per million of the substance multiplied by its density.
Monitored Natural Attenuation
- Natural attentuation that is expected to achieve site cleanup objectives within a time frame that is reasonable compared to more active cleanup methods. The natural attenuation processes are carefully monitored. Monitored Natural Attenuation is used in combination with "source control" or removing the contamination source as far as practicable.
- A well used to obtain water quality samples or measure groundwater levels.
- A well drilled to collect groundwater samples for testing to determine the amounts, types, and distribution of contaminants in the groundwater beneath the site. The well enables samples of groundwater to be collected at a specific horizontal and vertical location for chemical analysis. Sometimes soil samples are also collected as the well is being drilled.
National Priorities List (NPL)
- The U.S. Environmental Protection Agency's list of the most serious uncontrolled or abandoned hazardous waste sites identified for possible long-term remedial response using money from a special trust fund (Superfund).
- Relying on natural (physical, chemical, or biological) processes to reduce mass, toxicity, mobility, volume or concentration of compounds in earth or groundwater. Under proper conditions, can be used for perchloroethylene (PCE), trichloroethylene (TCE), and trichloroethane (TCA) at a lower cost than conventional remediation technologies.
- All land, fish, wildlife, biota, air, water, groundwater, drinking water supplies, and other such resources belonging to, managed by, held in trust by, or otherwise controlled by the State.
New York State Department of Health
- Agency within the executive branch of New York State government which: determines potential risk from environmental exposure at hazardous waste sites; conducts health-related community outreach around sites; and reviews remedial actions to assure that public health concerns are addressed.
New York State Department of Law
- Agency within the executive branch of New York State government which takes the lead on hazardous waste site litigation. Litigation can involve negotiations and court action with responsible parties to clean up sites; natural resources damage claims, and recovery of remedial costs.
New York State Registry of Inactive Hazardous Waste Disposal Sites
Non-aqueous phase liquids (NAPL)
- Liquids, commonly a mixture of several different chemicals, that are either denser or less dense than water. Dense NAPL (DNAPL), such as chlorinated solvents, will sink if it enters groundwater; less dense, or light NAPL (LNAPL), such as gasoline, will float on the water table. NAPL in the subsurface can be a persistent source of groundwater contamination due to its low solubility and viscosity.
Occupational exposure limits
- Maximum allowable concentrations of toxic substances in workroom air for workers.
- The lowest concentrations of a substance's vapor, in air, that can be smelled. Odor thresholds are highly variable, depending on the individual who breathes the substance and the nature of the substance.
- An administrative term used to identify a portion of a site that can be addressed by a distinct investigation and/or cleanup approach. For example, groundwater contamination at a site may be considered as one operable unit, and soil contamination at the same site may be dealt with as a second operable unit. An operable unit can receive specific investigation, and a particular remedy may be proposed. A Record of Decision is prepared for each operable unit.
Operation and maintenance (O&M)
- The period following construction of a remedy during which elements of the remedy must be operated and maintained. For example, after a groundwater collection and treatment system is installed (the remedial construction phase), operation of the groundwater collection system and treatment of the water would be part of the "Operation and Maintenance" phase of the remedial program. Activities could also include site inspections, groundwater well monitoring and other sampling.
Order on Consent
- See Consent Order
- In chemistry, any compound containing carbon.
- Referring to or derived from living organisms.
- Chemicals that contain carbon.
- The rock and soil in the ground above bedrock.
- A substance (compound) that will accept electrons from another compound, thus changing (oxidizing) the other compound.
- A material which may cause combustible materials to ignite without the aid of an external ignition source (such as flame) or which, when mixed with combustible materials, increases the rate of burning of these materials.
- New York State landfill regulations, including some regulations related to old landfills that contain hazardous waste.
- The portion of New York State regulations governing inactive hazardous waste disposal sites.
- Fine liquid or solid particles such as dust, smoke, mist, fumes, or smog, found in air or emissions.
Parts per billion (ppb)
- The concentration of a substance of air, water or soil. One ppb means that there is one part of a substance for every billion parts of the air, water or soil in which it is measured. One ppb is about one drop of dye in 18,000 gallons of water or about one second in 32 years. One ppb is 1,000 times less than one part per million.
Parts per million (ppm)
- The concentration of a substance in air, water or soil. One ppm means that there is one part of a substance for every million parts of the water or soil in which it is measured. One ppm is about one drop of dye in 18 gallons of water, about one inch in 16 miles, or one penny in $10,000.
Parts per trillion (ppt)
- The concentration of a substance in air, water or soil. One ppt means that there is one part of a substance for every trillion parts of the water or soil in which it is measured. One ppt is 1,000 times less than one part per billion.
PCBs (polychlorinated biphenyls)
- A group of toxic, persistent chemicals used in transformers for insulating purposes, in gas pipeline systems as a lubricant, and in some florescent light ballasts. The sale of PCBs was banned by law in 1979, but many old transformers still contain them.
- The movement of water through a porous substance such as soil.
Periodic review report (PRR)
- A report which evaluates the institutional and engineering controls, summarizes any monitoring results and/or evaluates any operation and maintenance activities.
- The rate at which liquids pass through soil or other materials in a specified direction. Water moves easily through a "high permeability" soil (such as gravel) and very slowly through a "low permeability" soil (such as clay).
- Substance or mixture of substances intended for preventing, destroying, repelling, or mitigating any pest. Some pesticides can accumulate in the food chain and/or contaminate the environment if misused.
- A measure of the acidity or alkalinity (how basic) of a liquid or solid material. It is related to the number of hydrogen ions in a substance.
Photo ionization detector (PID)
- A hand-held instrument used to measure the overall level of volatile organic compounds in air.
- An instrument used to measure the elevation of the water table, i.e. how far below the surface groundwater is located.
- An area of chemicals moving away from its source in a feather-like (hence the name, plume) shape. A plume, for example, can be a column of smoke drifting away from a chimney. An area of dissolved chemicals moving with groundwater is called a "groundwater contaminant plume."
- See PCBs
- A group of over 100 different chemicals that form during the incomplete burning of coal, oil and gas, garbage, or other organic substances like tobacco or charbroiled meat. PAHs are usually found as a mixture containing two or more of these compounds, such as soot. Some PAHs are manufactured. PAHs are found in coal tar, crude oil, creosote, and roofing tar, but a few are used in medicines or to make dyes, plastics, and pesticides. Most do not dissolve easily in water and stick tightly to soil particles.
Polynuclear aromatic hydrocarbons (PAHs)
- The percentage of the total volume of a given body of rock that is pore space. It is the portion of void (air) space in rock, soil, or sediment.
- Persons identified by the EPA under CERCLA or by New York State law as being responsible for the contamination at a hazardous waste site. By law, PRPs may be generators, present or former owners or operators of a site, or transporters of the hazardous substances.
- Rain or snow.
- Removal of solids from liquid waste so that the hazardous solid portion can be disposed of safely.
- Cleanup technique(s) that can be applied to hazardous waste sites with common characteristics. For example, old municipal landfills built without a liner often have similar characteristics. EPA has developed a "presumptive remedy" for this type of site. Essentially, EPA said "Here's a site similar in all key ways to many other sites we've cleaned up. Wouldn't it make sense to use that cleanup approach here too?"
- A DEC staff member within the Division of Environmental Remediation (usually an engineer, geologist, or hydrogeologist) responsible for the remedial program at a hazardous waste site. The project manager works with the Office of Communication Services, fiscal and legal staff and the Department of Health to accomplish site-related goals and objectives.
- A document outlining alternatives considered by the Division of Environmental Remediation for the remediation of a hazardous waste site and highlighting the alternative preferred by DEC. The PRAP is based on information developed during the site's Remedial Investigation and Feasibility Study. The PRAP is reviewed by the public and other state agencies.
- A formal hearing at which the public has the opportunity to submit comments and testimony on proposed actions for the public record.
- A scheduled gathering of DEC staff and the public to give and receive information, ask questions and discuss concerns.
Publicly owned treatment works (POTW)
- A wastewater system, owned by a municipality, state, or tribe that is used for the collection, treatment, and/or disposal of sewage. Usually POTW refers specifically to the sewage treatment plant.
Pump and treat
- A method used to collect and treat contaminated groundwater. Typically, groundwater is collected in a well or trench and pumped to a treatment system.
Qualitative exposure assessment
- An evaluation to determine the route, intensity, frequency, and duration of actual or potential exposures of humans and/or fish and wildlife to contaminants.
Quality assurance (QA)/ quality control (QC)
- A system of procedures, checks, audits, and corrective actions to ensure that environmental sampling and testing are of the highest achievable quality.
- The ability of a substances to undergo change, usually by combining with another substance or by breaking down. Certain conditions, such as heat and light, may cause a substance to become more reactive. Highly reactive substances may explode.
- During construction or investigation activities, continuous monitoring of air with equipment that gives immediate read-outs; that is, samples don't need to be sent to a laboratory to obtain results.
- The replenishment of groundwater by infiltration of rain and snow through the soil.
- A process by which the Division of Environmental Remediation redefines the threat posed by a hazardous waste site to public health and the environment by developing and assessing site information and, based on findings and conclusions, assigning the site a new classification code (see Site Classification).
- A document which provides the definitive record of the cleanup alternative that will be used to remediate a hazardous waste site. The ROD is based on the Remedial Investigation / Feasibility Study and public comment.
- Often referred to as "the Registry," this is a compilation of all known and suspected hazardous waste sites (meeting certain criteria) in New York State.
- Any pumping, pouring, emitting, emptying or leaching, directly or indirectly, of a contaminant so that the contaminant or any related constituent thereof, or any degradation product of such a contaminant or of a related constituent thereof, may enter the environment, or the disposal of any contaminant.
Remedial/ remediate/ remediation
- Refers to any procedures or strategies used to address a hazardous waste site. For example, a Remedial Investigation determines what areas of a site need to be addressed (cleaned up or remediated), a proposed remedial action plan describes remedial actions (cleanup methods or corrective actions) that have been recommended for a specific site; remediation of a site could include removing contaminated soil.
Remedial action (RA)
- Action taken to remove, destroy, reduce, or prevent the spread of contamination at a hazardous waste site.
Remedial construction (RC)
- The physical development, assembly and implementation of the alternative selected to remediate a site. For example, remedial construction could include installing a groundwater collection and treatment system. Construction follows a remedial design stage.
Remedial design (RD)
- The process following finalization of a Record of Decision in which plans and specifications are developed for the implementation of the alternative selected to remediate (clean up) a site.
Remedial Investigation (RI)
Studies designed to gather the data necessary to determine the type (nature) and extent (location) of contamination at a hazardous waste site. The RI is usually performed at the same time as a Feasibility Study in a process known as the "RI/FS." This process is designed to:
- Establish criteria for cleaning up the site.
- Identify and screen cleanup alternatives for remedial action; and
- Analyze in detail the technology and costs of the alternatives.
- DEC's efforts to investigate and clean up remedial sites. A remedial program is designed to correct releases or potential releases of hazardous materials into the environment. DEC takes several steps as part of each site's remedial program: it investigates contamination (Remedial Investigation), analyzes different methods to address threats posed by the site (Feasibility Study or Remedial Alternatives Report), proposes a cleanup plan (Proposed Remedial Action Plan), selects a final plan (Record of Decision or Decision Document), and designs and implements the plan (Remedial Design and Remedial Action).The program includes post-remedial site management.
- See remedial program.
- Actions taken to prevent or mitigate the release of hazardous materials into the environment at hazardous waste sites and brownfield sites. The word "remedy" is used in the sense of a "cure" or "corrective action."
- Often less burdensome and extensive than remedial actions, a removal action is intended to be a quick, temporary response to a release or the threat of release of a hazardous material at a hazardous waste site. A removal action could involve removing drums of hazardous material, contaminated soil or contaminated sediment and taking these items to a proper disposal facility.
Residual / residue
- The quantity of a substance, its degradation products, and/or its metabolites remaining on or in the soil or groundwater. "Residual contamination" usually refers to low levels of chemicals that may be left in soil, bedrock or groundwater after cleanup of hazardous wastes.
Resource Conservation and Recovery Act (RCRA)
- Federal law governing the treatment, storage, handling, disposal, and overall management of solid and hazardous wastes.
- A formal or informal written summary and response by the DEC to public questions and comments. A responsiveness summary is prepared following a public meeting about a Proposed Remedial Action Plan and may also be prepared after other public meetings. The responsiveness summary may list and respond to each question, or summarize and respond to questions in categories.
- A type of pressurized filtration system in which water is forced through a semipermeable membrane that allows the passage of water but restricts many contaminants.
- Large fragments of broken rock, thrown together irregularly or fitted together (as on the down-stream face of a dam). Its purpose is to prevent erosion by waves or currents and thereby preserve a surface, slope, or underlying structure. It is used for irrigation channels, river-improvement works, spillways at dams, and sea walls for shore protection.
- The chance of an injury, illness, or death caused by exposure to a hazard.
- The qualitative and quantitative evaluation performed in an effort to define the risk posed to human health and/or the environment by the presence or potential presence and/or use of specific pollutants.
- Small amounts of air, water, or soil are obtained and tested to determine the levels of different hazardous chemicals contained in them.
- See Landfill
- A subsurface area in which all pores and cracks in rock and/or soil are filled with water.
- A device for removing unwanted gases or particles from an air stream by spraying the air with liquid (usually water) or forcing air through a series of baths. Scrubbers are often put on smoke stacks.
- Soil, sand, and minerals washed by rain from land into water that accumulates on the bottom of ditches, streams, rivers and lakes.
- The cleanup alternative selected by the state as the most feasible.
- The cleanup alternative selected for a site on the National Priorities List based on technical feasibility, permanence, reliability, and cost.
Semi-volatile organic compounds (SVOCs)
- Chemicals similar to volatile organic compounds but that do not evaporate as readily. Polynucleated aromatic hydrocarbons are semi-volatile compounds.
DEC assigns inactive hazardous waste disposal sites classifications established by state law, as follows:
- Class 1 - A site causing or presenting an imminent danger of causing irreversible or irreparable damage to the public health or environment - immediate action required.
- Class 2 - A site posing a significant threat to the public health or environment - action required.
- Class 3 - Site does not present a significant threat to the public health or the environment.
- Class 4 - A site which has been properly closed - requires continued management.
- Class 5 - A site which has been properly closed, with no evidence of present or potential adverse impact - no further action required.
DEC assigns non-registry sites classifications as follows:
- Active (A) - Work is underway and not yet complete.
- Completed (C) - Remediation has been satisfactorily completed under a remedial program.
- The activities undertaken as the last phase of the remedial program at a site which continue after a certificate of completion (closure letter) is issued. Site management is conducted in accordance with a site management plan, which identifies and implements the institutional and engineering controls required for a site, as well as any necessary monitoring and/or operation and maintenance of the remedy
Site management plan (SMP)
- A document which details the institutional and engineering controls required for a site and any physical components of the remedy required to be operated, maintained and monitored to assure continued effectiveness
- A semi-solid residue from any of a number of industrial processes or air or water treatment processes. Sludge can be a hazardous waste.
- A watery mixture that does not contain a significant amount of dissolved materials.
- An underground wall designed to stop groundwater flow; constructed by digging a trench and backfilling it with a slurry rich in bentonite clay.
- A circular hole made in the ground by an auger or mechanical drill rig to collect soil samples deep in the ground. Representative samples are collected for testing to see if the subsoil has been contaminated. Sometimes these borings are converted into groundwater monitoring wells.
- Air in the spaces between soil particles. Contaminants can be trapped in this air.
Soil gas survey
- A method for investigating underground distributions of volatile organic compounds (VOCs) by looking for their vapors in the shallow soil gas. The presence of VOCs in shallow soil gas indicates the VOCs may be in the unsaturated (dry) soil or in the groundwater below the probe. This survey is used to trace the outline of a contaminant plume and help determine the best location to install groundwater monitoring wells.
Soil Vapor Extraction System (SVE)
- An in-situ remediation technique that applies a vacuum to a series of wells ("vapor extraction wells") and induces air flow through contaminated soil. As the air migrates through the soil, volatile organic compounds (VOCs) volatilize (evaporate) and move with the air to the extraction wells where they are removed from the subsurface. If the concentration of VOCs in the extracted air is high, the air maybe treated by a carbon adsorption system before being released to the atmosphere. In some cases, dual phase vacuum extraction is used to treat both groundwater and the overlying soil.
- Non-liquid, non-soluble materials ranging from municipal garbage to industrial wastes that contain complex, and sometimes hazardous, substances. Solid wastes also include sewage sludge, agricultural refuse, demolition wastes, and mining residues.
- The amount of a substance that can be dissolved in water or (sometimes) another substance.
- A substance (usually a liquid) capable of dissolving one or more other substances. For example, paint remover is a paint solvent.
- To take up and hold by either adsorption or absorption.
- An area from which groundwater contamination is believed to originate. For example, Company A spilled a 55 gallon drum of trichloroethene (TCE) onto the ground near a loading dock at their facility. The TCE spread through the soil and contaminated groundwater around the facility. Because the contamination originated in the loading dock area, this area is the "source area." Over time, the highly concentrated TCE in the source area would continue to slowly spread through groundwater and soil, acting as a continuous "source" of groundwater contamination. Thus, the most effective way to slow down and prevent further spreading of contamination would be to address the source area.
SPDES permit (pronounced SPEEDIES)
- A soil sample from a hazardous waste site that is divided between the potentially responsible parties (PRPs) and the DEC or the Health Department. It functions as a system of checks and balances since both the PRPs and the DEC analyze their half of the sample. The results of the two analyses can then be compared.
- A sample of unconsolidated material taken by driving a sampling device (split spoon) into the soil ahead of a drill bit in a soil boring. A split-spoon sampler is typically driven into the soil by repeatedly dropping a weight.
Standards, criteria and guidance values (SCGs)
- Values that indicate acceptable or normal levels of various contaminants in the environment. These values are used to establish cleanup goals at hazardous waste sites. Depending on the chemical, the values are developed by the U.S. Environmental Protection Agency, DEC and/or the New York State Department of Health.
- A permit issued by the DEC as part of the SPDES program, which is designed to maintain New York's waters with reasonable standards of purity. State law requires a SPDES permit before construction or use of an outlet or discharge pipe for wastewater discharging into surface water or groundwater, and for construction or operation of disposal systems such as sewage treatment plants.
- A pit or tank that catches liquid runoff for drainage or disposal.
- Federal and state programs to investigate and clean up inactive hazardous waste disposal sites. The federal program gives the U.S. Environmental Protection Agency the funding and authority to investigate, rank and con-duct or supervise cleanup of sites on the National Priority List. New York State's program gives DEC the same authority to deal with sites that do not qualify for the federal superfund list, but meet certain other qualifications.
Superfund Amendments and Reauthorization Act (SARA)
- Modifications to CERCLA enacted in 1986. Sometimes referred to as the "Right to Know Law," it requires, among other things, that industry provide the government with information on the use and release of certain chemicals into the environment. This information is then made available to the public.
- All water naturally open to the atmosphere. Refers to water in rivers, lakes, reservoirs, streams, impoundments, seas, estuaries, and so on.
- A slight depression, sometimes swampy, in the midst of generally level land.
Technical and Administrative Guidance Memorandum (TAGM)
- An official internal Division of Environmental Remediation document that outlines divisional policies or recommended guidance for topics such as determining cleanup goals at hazardous waste sites.
Technical Assistance Grant Program (TAG Program)
- A NYS grant program that provides funds for qualified citizens' groups to hire independent technical advisors to help them understand and comment on technical decisions relating to state cleanup actions at sites that pose a significant threat to public health or the environment.
Technical and Operational Guidance Series (TOGs)
- DEC Division of Water's documents listing water quality standards and guidance values.
- A small excavation at a hazardous waste site. Investigators dig test pits to get an idea of subsurface conditions at hazardous waste sites.
- A clear, colorless, non-flammable liquid with a characteristic odor. It is a widely used solvent, especially as a dry cleaning agent and as a degreaser.
- A dose or exposure below which there is no measurable adverse effect.
- The degree of danger posed by a substance to animal or plant life.
Toxicity Characteristic Leaching Procedure
- Laboratory test used to determine the mobility of organic and inorganic contaminants present in liquid, solid, and multiphase wastes. If an extract from a representative sample is shown to contain any contaminant in an amount exceeding the levels allowed by regulations, the waste is banned for land disposal unless properly treated.
- A chemical or mixture that may present an unreasonable risk of injury to health or the environment.
Toxic Substances Control Act (TSCA) of 1976
- A federal law that provides for testing of manufactured substances to determine toxic or otherwise harmful characteristics and regulation of the manufacture, distribution, use, and disposal of regulated substances.
- Tests of potential cleanup technologies conducted in a laboratory.
- Pilot-scale type tests conducted at hazardous wastes sites to determine if a treatment technology will work for that site's particular set of environmental conditions.
Treatment, storage, and disposal facility(TSDF)
- A site where a hazardous substance is treated, stored or disposed of. TSDF facilities are regulated by EPA and states under the Resource Conservation and Recovery Act.
1,1,1-Trichloroethane (1,1,1 TCA)
- Colorless, non-flammable, man-made liquid solvent used as a degreaser, a dry-cleaning agent, and a propellant.
Trichloroethene or Trichloroethylene (TCE)
- A colorless, man-made liquid used primarily as a solvent for removing grease from metal. It has a variety of other uses such as a dry cleaning solvent and in the production of other chemicals. It generally gets into drinking water by improper waste disposal.
- An aquifer in which water is not contained by an impermeable layer of rock or soil. The water level in the aquifer may rise or fall according to the volume of water stored, which varies according to seasonal cycles of natural recharge.
- The area of soil and rock between the land surface and the water table. The spaces between soil particles (pore spaces) in the unsaturated zone contain mostly air, but water occurs there as soil moisture.
- The underground zone between the land surface and the water table; essentially the unsaturated zone.
- The gas given off by a solid or liquid substance at ordinary temperatures.
- The process where volatile chemicals move frm a subsurface source into the indoor air of overlying or adjacent buildings.
- A colorless gas used in the manufacture of polyvinyl chloride and other resins, and as a chemical intermediate and as an industrial solvent. Vinyl chloride is a carcinogen.
- The property of a fluid describing its resistance to flow.
- Description of any substance that evaporates easily.
Volatile organic compounds (VOCs)
- Carbon-containing chemicals which readily evaporate (cleaning solvents, gasoline, etc.). Many common industrial chemicals are VOCs, including trichloroethene, 1,1,1-trichloroethane, and tetrachloroethene.
- Any garbage, refuse, sludge from a waste water treatment plant, water supply treatment plant, or air pollution control facility, and other discarded material, including solid, liquid, semi-solid, or contained gaseous material resulting from industrial, commercial, mining, and agricultural operations or from community activities, and source, special nuclear or by-product material.
- The area underground in which pores and cracks in rock and/or soil are normally filled with water. Therefore, if a well is drilled into this area, water can be drawn out on a regular basis.
- The level of groundwater; the boundary between the unsaturated zone and the saturated zone.The water-table generally reflects surface topography and varies with changes in land surface elevations.
- A wall or plate in a open channel to measure the flow of water.
- A wall or obstruction used to control flow from settling tanks, clarifiers, or a drainage system to ensure a uniform flow rate.
- An area that is regularly saturated by surface water or groundwater. Examples of wetlands include swamps, bogs, fens, marshes, and estuaries.