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Glossary of Superfund Technical Terms

Administrative Order on Consent –A legal agreement signed by EPA and an individual, business, or other entity through which the violator agrees to pay for correction of violations, take the required corrective or cleanup actions, or refrain from an activity. It describes the actions to be taken, may be subject to a comment period, applies to civil actions, and can be enforced in court. (Source: EPA Terms of the Environment)

Air Stripping –The process of forcing air through polluted ground water or surface water to remove harmful chemicals via evaporation. The evaporated contaminated gas is then collected and cleaned. (Source: A Citizen’s Guide to Air Stripping)

Capping –Capping involves placing a cover over contaminated material such as waste buried at a landfill. Such covers are called “caps.” Caps do not clean up the contaminated material. They just keep it in place so it will not come into contact with people or the environment. (Source: A Citizen’s Guide to Capping)

Contaminants – Any physical, chemical, biological, or radiological substance or matter that has an adverse effect on air, water, or soil. (Source: EPA Terms of the Environment)

Contaminants of Concern (COCs) – COCs are the chemical substances found at the site that the EPA has determined pose an unacceptable risk to human health or the environment. These are the substances that are addressed by cleanup actions at the site. (Source: EPA Superfund Information Systems)

Consent Decree –A legal document, approved by a judge, that formalizes an agreement reached between EPA and potentially responsible parties (PRPs) through which PRPs will conduct all or part of a cleanup action at a Superfund site; cease or correct actions or processes that are polluting the environment; or otherwise comply with EPA initiated regulatory enforcement actions to resolve the contamination at the Superfund site involved. The consent decree describes the actions PRPs will take and may be subject to a public comment period. (Source: EPA Terms of the Environment)

Contamination – Introduction into water, air, and soil of microorganisms, chemicals, toxic substances, wastes, or wastewater in a concentration that makes the medium unfit for its next intended use. Also applies to surfaces of objects, buildings, and various household and agricultural use products. (Source: EPA Terms of the Environment)

Corrective Action Management Units –special units created under the Resource Conservation and Recovery Act (RCRA) to facilitate treatment, storage, and disposal of hazardous wastes managed for implementing cleanup, and to remove the disincentives to cleanup that the application of RCRA to these wastes can sometimes impose. (Source: EPA Office of Solid Waste and Emergency Response)

Dense Non-aqueous Phase Liquid (DNAPL) –Non-aqueous phase liquids such as chlorinated hydrocarbon solvents or petroleum fractions with a specific gravity greater than 1.0 that sink through the water column until they reach a confining layer. Because they are at the bottom of aquifers instead of floating on the water table, typical monitoring wells do not indicate their presence. (Source: EPA Terms of the Environment)

Excavation (Soil) – Process of digging up polluted soil so it can be cleaned or disposed of properly in a landfill. (process of digging up polluted soil) (source: A Citizen’s Guide to Soil Excavation)

Extraction Procedure (EP Toxic) 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." (Source: EPA Terms of the Environment)

Explanation of Significant Differences –A CERCLA decision document prepared when there has been a significant change in cost, performance, or cost of a remedy selected in a Record of Decision (ROD). The significant change to the remedy may be as a result of new information.

Feasibility Study – An analysis of the practicability of a proposal that may include a cost-effective alternative, and usually starts as soon as the remedial investigation is underway; together, they are commonly referred to as the "RI/FS". (Source: EPA Terms of the Environment)

Federal Facilities Agreement – CERCLA requires federal agencies to investigate and clean up contamination at their facilities. Federal facilities that are significantly contaminated may be placed on the CERCLA National Priorities List (NPL). For such facilities CERCLA requires that EPA and the federal facility enter into an interagency agreement (IAG -- sometimes called a Federal Facility Agreement) to govern the cleanup to be done. States often are signatories to these agreements too. (Source: EPA Compliance and Enforcement)

Five-Year Reviews – Five-year reviews provide an opportunity to evaluate the implementation and performance of a remedy to determine whether it remains protective of human health and the environment. Generally, reviews are performed five years following the initiation of a CERCLA response action, and are repeated every succeeding five years so long as future uses remain restricted. Five-year reviews can be performed by EPA or the lead agency for a site, but EPA retains responsibility for determining the protectiveness of the remedy. (Source: EPA Superfund)

Human Exposure Under Control – Superfund Environmental Indicators are measures of program performance used to communicate tangible progress made in protecting human health and the environment through site cleanup activities. Sites are classified as meeting the Site-wide Human Exposure Environmental Indicator if there are no unacceptable human exposure pathways and the EPA Region has determined the site is under control for current conditions site wide.  (Source: EPA Superfund)

Institutional Controls –Non-engineered instruments, such as administrative and legal controls, that help to minimize the potential for human exposure to contamination and/or protect the integrity of a response action. They are typically used in conjunction with, or as a supplement to, other measures, such as waste treatment or containment. There are generally four categories of ICs: governmental controls; proprietary controls; enforcement and permit tools with IC components; and information devices. (Source: Interim Final Guidance, Institutional Controls: A Guide to Planning, Implementing, Maintaining, and Enforcing Institutional Controls at Contaminated Sites)

Land Use Controls – Any restriction or control, including institutional controls and engineering controls, arising from the need to protect human health and the environment, such as the restriction of access or limitation of activities at a site that has residual contamination. Land use controls include engineering and physical barriers, such as fences and security guards, as well as institutional controls. (Source: Interim Final Guidance, Institutional Controls: A Guide to Planning, Implementing, Maintaining, and Enforcing Institutional Controls at Contaminated Sites (PDF) (37 pp, 700K, About PDF) )

Monitored natural attenuation (MNA) –Natural attenuation (reduction in strength) relies on natural processes to clean up or attenuatepollution in soil and groundwater. Natural attenuation occurs at most polluted sites. However, the right conditions must exist underground to clean sites properly. If not, cleanup will not be quick enough or complete enough. Scientists monitoror test these conditions to make sure natural attenuation is working. This is called monitored natural attenuation or MNA. (Source: A Citizen’s Guide to Monitored Natural Attenuation)

Non-Aqueous Phase Liquid (NAPL)Contaminants that remain undiluted as the original bulk liquid in the subsurface, e.g. spilled oil. (Source: EPA Terms of the Environment)

National Priorities List – EPA's list of the most serious uncontrolled or abandoned hazardous waste sites identified for possible long-term remedial action under Superfund. The list is based primarily on the score a site receives from the Hazard Ranking System. EPA is required to update the NPL at least once a year. A site must be on the NPL to receive money from the Trust Fund for remedial action. (Source: EPA Terms of the Environment)

Operable Unit (OU) Term for each of a number of separate activities undertaken as part of a Superfund site cleanup. A typical operable unit would be removal of drums and tanks from the surface of a site. (Source: EPA Terms of the Environment)

Permeable reactive barrier a wall built below ground to clean up polluted ground water. (Source: A Citizen’s Guide to Permeable Reactive Barriers)

Prospective Purchaser Agreement An agreement between EPA or a state and the prospective purchaser of a property known to be contaminated. Under the agreement, EPA or the state typically provides the purchaser with a covenant not to sue for the contamination existing at the site as of the date of the agreement. In return, the purchaser usually provides EPA with a benefit, which may include carrying out actual cleanup work and/or funding for cleanup at the site. EPA generally would enter into such an agreement at sites where an EPA action has been, is currently being, or will be taken. Parties seeking to operate on or lease contaminated property also may be eligible for such an agreement. (Source: Interim Final Guidance, Institutional Controls: A Guide to Planning, Implementing, Maintaining, and Enforcing Institutional Controls at Contaminated Sites)

Pump and treat A ground water cleanup method in which pumps are used to bring polluted ground water to the surface where it can be treatment. (Source: A Citizen’s Guide to Pump and Treat)

Record of Decision – A public document that explains which cleanup alternative(s) will be used at National Priorities List sites where, under CERCLA, Trust Funds pay for the cleanup. (Source: EPA Terms of the Environment)

Remedial design A phase of remedial action that follows the remedial investigation/feasibility study and includes development of engineering drawings and specifications for a site cleanup.  (Source: EPA Terms of the Environment)

Risk Assessment - An analysis that uses information about toxic substances at a site to estimate a theoretical level of risk for people who might be exposed to these substances. (source: ATSDR)

Remedial Investigation –A study designed to gather data needed to determine the nature and extent of contamination at a Superfund site; establish site cleanup criteria; identify preliminary alternatives for remedial action; and support technical and cost analyses of alternatives. (source: Site Cleanup Terms)

Soil Vapor Extraction - Soil vapor extraction or SVE removes harmful chemicals, in the form of vapors, from the soil above the water table. Vapors are the gases that form when chemicals evaporate. The vapors are extracted (removed) from the ground by applying a vacuum to pull the vapors out. (Source: A Citizen’s Guide to Soil Vapor Extraction and Air Sparging)

Source –An area where a hazardous substance may have been deposited, stored, disposed, or placed.  Also, soil that may have become contaminated as a result of hazardous substance migration.  In general, however, the volumes of air, ground water, surface water, and surface water sediments that may have become contaminated through migration are not considered sources. (Source: Superfund Glossary of Terms and Acronyms)

Superfund alternative approach – The Superfund alternative (SA) approach uses the same investigation and cleanup process and standards that are used for sites listed on the NPL. The  SA approach is an alternative to listing a site on the NPL; it is notan alternative to Superfund or the Superfund process. More information on the Superfund alternative approach.

Superfund liability –The Superfund law (officially the Comprehensive Environmental Response, Compensation and Liability Act, "CERCLA") imposes liability on parties responsible for, in whole or in part, the presence of hazardous substances at a site. (Source: EPA Office of Compliance and Enforcement)

Technical impracticability waiver Remedial alternatives at Superfund sites must satisfy two “threshold” criteria specified in the National Contingency Plan (NCP) to be eligible for selection: 1) the remedy must be protective of human health and the environment; and 2) the remedy must meet (or provide the basis for waiving) the Applicable or Relevant and Appropriate Requirements (ARARs). ARARs may be waived by EPA for any of the six reasons specified by CERCLA and the NCP, including technical impracticability from an engineering perspective. (Source: EPA Superfund)

Thermal treatment – Soil cleanup method that involves the use of elevated temperatures to treat hazardous wastes. (Source: Site  Cleanup Terms)

Toxicity - The degree to which a substance or mixture of substances can harm humans or animals. Acute toxicity involves harmful effects in an organism through a single or short-term exposure. Chronic toxicity is the ability of a substance or mixture of substances to cause harmful effects over an extended period, usually upon repeated or continuous exposure sometimes lasting for the entire life of the exposed organism. Subchronic toxicity is the ability of the substance to cause effects for more than one year but less than the lifetime of the exposed organism. . (Source: EPA Terms of the Environment)

Toxicity Characteristic Leaching Procedure (TCLP) Toxic wastes are harmful or fatal when ingested or absorbed (e.g., containing mercury, lead, etc.). When toxic wastes are land disposed, contaminated liquid may leach from the waste and pollute ground water. Toxicity is defined through a laboratory procedure called the Toxicity Characteristic Leaching Procedure (TCLP) (Method 1311) (PDF) (35 pp, 288K). The TCLP helps identify wastes likely to leach concentrations of contaminants that may be harmful to human health or the environment. (Source: EPA Hazardous Waste)

Unilateral Administrative Order –A legal document signed by EPA directing any person to take corrective action or refrain from an activity. It describes the violations and actions to be taken, and can be enforced in court. (Source: Interim Final Guidance, Institutional Controls: A Guide to Planning, Implementing, Maintaining, and Enforcing Institutional Controls at Contaminated Sites)

Well Field –Area containing one or more wells that produce usable amounts of water or oil. (Source: EPA Terms of the Environment)

Windfall Lien A CERCLA statutory lien on a property for the increase in the fair market value of that property attributable to EPA’s cleanup efforts. (Source: EPA Office of Compliance and Enforcement)


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