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AOU: Accelerated Operable Unit

An Accelerated Operable Unit is a type of Operable Unit (OU) identified by agreement between a Potentially Responsible Party (PRP) and the regulating agencies. The purpose of an AOU is to allow for remedial actions to occur in advance of some of the standard Superfund process steps. In other words, immediate threats can be mitigated faster if they are identified.

AOU-1: Accelerated Operable Unit 1

For the purposes of the 700 South 1600 East PCE Plume Site, AOU-1 is primarily to determine if any immediate threats to human health and the environment exist at the East Side Springs, and if so, mitigate them.

AR: Administrative Record

A file that is maintained and available to the public and contains information used to make decisions on the selection of a response action under the Comprehensive Environmental Response, Compensation and Liability Act (CERCLA).

ATSDR: Agency for Toxic Substances and Disease Registry

The ATSDR is a health agency of the U.S. Department of Health and Human Services. ATSDR serves the public by using the best science, taking responsive public health actions, and providing trusted health information to prevent harmful exposures and diseases related to toxic substances.

CERCLA: Comprehensive Environmental Response, Compensation and Liability Act

This law, enacted by Congress on December 11, 1980, created the Superfund program. Specifically, CERCLA (1) established prohibitions and requirements concerning closed and abandoned hazardous waste sites, (2) provided for liability of persons responsible for releases of hazardous waste at these sites, and (3) established a trust fund to provide for cleanup when no responsible party could be identified.

EPA: U.S. Environmental Protection Agency (EPA)

The EPA was created in 1970 for the purpose of protecting human health and the environment by writing and enforcing regulations based on laws passed by Congress.

FS: Feasibility Study

The feasibility study (FS) is an analysis of the practicability of a proposal (e.g., a description and analysis of potential cleanup alternatives), which usually recommends selection of a cost-effective alternative.

GC/MS: Gas Chromatograph/Mass Spectrometer

An analytical method that combines the features of gas-chromatography and mass spectrometry to identify and quantify concentrations of different chemical substances within a test sample.

NPL: National Priorities List

EPA's list of the most serious uncontrolled or abandoned hazardous waste sites identified for possible long-term remedial action under the Superfund program. The NPL, which EPA is required to update at least once a year, is based primarily on the score (1 to 100) a site receives from EPA's Hazard Ranking System. A site must be on the NPL to receive money from the Superfund Trust Fund for remedial action. EPA’s Hazard Ranking System score for the 700 S 1600 E PCE Plume was 50.

OU: Operable Unit

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.

OU-2: Operable Unit 2

For the purposes of the 700 South 1600 East PCE Plume Site, the purpose of OU-2 is to evaluate and mitigate, to the extent feasible, any long-term threats from the Plume to human health and the environment.

PA/SI: Preliminary Assessment/Site Investigation (PA/SI)

The Preliminary Assessment (PA) is the process of collecting and reviewing available information about a known or suspected waste site or release. The Site Investigation (SI) is the collection of information from a Superfund site to determine the extent and severity of hazards posed by the site. This phase follows and is more extensive than a preliminary assessment. The purpose of the SI is to gather information necessary to score the site using the Hazard Ranking System, and to determine if the site presents an immediate threat requiring prompt removal. Together, these two processes are referred to as "PA/SI."

PCE: Tetrachloroethylene (PCE)

Tetrachloroethylene (PCE) is a synthetic chemical that is widely used for dry cleaning fabrics and for metal-degreasing operations. It is also used as a starting material (building block) for making other chemicals and is used in some consumer products. PCE is a nonflammable, colorless liquid at room temperature and has a sharp, sweet odor. Other names for PCE include perchloroethylene, perc, tetrachloroethene, perclene and perchlor.

ppb: parts per billion

1 ppb, or part per billion, indicates the presence of a singular unit of something within a whole of one billion units. 1 ppb = 0.0000001%

ppbv: parts per billion by volume

Where parts per billion (ppb) is used to relay ratios of weight-to-weight or weight-to-volume, parts per billion by volume (ppbv) is used to relay ratios of volume-to-volume. For PCE, ppb is used for relaying ratios/concentrations in water or soil, but ppbv is used for relaying ratios/concentrations in air or in soil gas.

PRP: Potentially Responsible Party (PRP)

An individual or company that is potentially responsible for the contamination problems at a Superfund site. Whenever possible, EPA requires PRPs to clean up hazardous waste sites they have contaminated.

RAL: Removal Action Level (RAL)

The concentration level established between the Potentially Responsible Party (PRP) and the regulators, which if exceeded, removal actions will occur.

RI: Remedial Investigation (RI)

The remedial investigation (RI) is an in-depth study to determine the nature and extent of contamination at a Superfund site.

RI/FS: Remedial Investigation and Feasibility Study (RI/FS)

Two stages of the Superfund process that are commonly considered together and abbreviated to RI/FS.

UDEQ: Utah Department of Environmental Quality (UDEQ)

UDEQ protects human health and the environment by writing and enforcing regulations based on laws passed by the Utah State Legislature.

VA: U.S. Department of Veterans Affairs (VA)

The U.S. Department of Veterans Affairs is a federal agency charged to fulfill President Lincoln’s promise “To care for him who shall have borne the battle, and for his widow, and his orphan” by serving and honoring the men and women who are America's veterans. This is accomplished through the offices of Veterans Benefits Administration; Veterans Health Administration; and the National Cemetery Administration.

VAMC: George E. Wahlen VA Medical Center

The George E. Wahlen VA Medical Center is a Veterans Health Administration medical center in Salt Lake City, Utah. For brevity on this website, it is abreviated to VAMC, though there are many other Veterans Affairs medical centers across the nation.

VI: Vapor Intrusion (VI)

Volatile organic compounds (VOCs) in contaminated soils or contaminated groundwater can emit vapors that may migrate through the soil and other air spaces of overlying buildings. This phenomenon is generally referred to as "vapor intrusion." Contaminated vapors may enter buildings through cracks in basements and foundations, sewer lines and other openings.



Water beneath the ground surface.


A portable gas chromatograph/mass spectrometer (GC/MS) developed by INFICON, designed for on-scene detection, identification and quantitation of chemicals. Users receive confirmatory results within minutes that are necessary to make critical decisions affecting life, health, safety.

near-slab soil gas

A sample taken near the slab/foundation elevation of a building, which is analyzed for vapors that might be found in the soil.

open-field soil gas

A sample taken from an open field area, which is analyzed for vapors that might be found in the soil.


A volume of contaminated groundwater that extends downward and outward from a specific source; the shape and movement of the mass of the contaminated water is affected by the local geology, materials present in the plume, and the flow characteristics of the area groundwater.

shallow groundwater sampling

A groundwater sample taken at shallow depths and analysed for the contaminants of concern.


A commonly used name for the Comprehensive Environmental Response, Compensation and Liability Act (CERCLA) and its process steps. The Superfund name derives from EPA’s initial funding of CERCLA as a one-time tax on U.S. oil refineries and chemical manufacturers.

surface water sampling

A surface water sample taken and analyzed for the contaminants of concern.