Glossary Of Key Terms Used

Above Ground Storage Tank (AST):

any tank, other than an underground storage tank, used to store any of the following petroleum products: gasoline, diesel, kerosene, used oil or heating oil.


real property, the expansion redevelopment, or reuse of which may be complicated by the presence or potential presence of a hazardous substance, pollutant or contaminant.

Conceptual Model:

A model of how chemicals were released at a site, their transport mechanism, and exposure routes for both ecological and human receptors.


Any physical, chemical, biological, or radiological material that can potentially have adverse impacts on environmental media, or that can adversely impact public health and the environment. It represents any undesirable substance/material that normally is not present in the environmental media of concern.

Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA):

Commonly known as Superfund, was enacted by Congress on December 11, 1980. This law created a tax on the chemical and petroleum industries and provided broad Federal authority to respond directly to releases or threatened releases of hazardous substances that may endanger public health or the environment. Over five years, $1.6 billion was collected and the tax went to a trust fund for cleaning up abandoned or uncontrolled hazardous waste sites. CERCLA established prohibitions and requirements concerning closed and abandoned hazardous waste sites; provided for liability of persons responsible for releases of hazardous waste at these sites; and established a trust fund to provide for cleanup when no responsible party could be identified. Corrective Action: Remedial actions taken when a release of a hazardous material has occurred and has impacted the environment. A typical example involves the remediation of chemical contamination in soil and groundwater.

Dense Nonaqueous Phase Liquid (DNAPL):

liquids that have low aqueous solubilities (immiscible) and have a greater density than water. They are characterized by their component composition, density, viscosity, and interfacial tension with water. Common DNAPLs include compounds that have been and are still widely used in industrial and commercial processes. Possibly the most common DNAPLs are halogenated solvents such as trichloroethylene (TCE) and tetrachloroethylene (PCE). These DNAPLs have been used as degreasers in many industrial processes and have frequently been released to the subsurface. Other DNAPLs include, but are not limited to, coal tar, creosote, some pesticides, and polychlorinated biphenyls.

Free Product:

refers to an immiscible fluid such as gasoline or a chlorinated solvent. In the subsurface free product may be continuous and able to flow independently of groundwater.

Flexible/Dynamic Work Plan:

a workplan that allows the project teams to make decisions in the field about how subsequent site activities will progress. Workplans provide the strategy for how dynamic field activities will take place. As such, they document a flexible, adaptive sampling and analytical strategy.

Global Positioning System:

a network of satellites that continuously transmit coded signals that make it possible to precisely map locations on the earth’s surface.

Hazardous Material:

all petroleum and toxic, corrosive or other chemicals and related sludge included in any of the following: I. Any substance defined in section 101(14)of the federal Comprehensive Environmental Response, Compensation and Liability Acto of 1980
II. Petroleum, including crude oil or any fraction thereof III. Hazardous wastes, Does not include herbicides and pesticides when applied consistent with good practice conducted in conformity with federal, state and local laws and regulations and according to manufacturer’s instructions.

Hazardous Waste:

any waste or combination of wastes of a solid, liquid, contained gaseous, or semi-solid form, including but not limited to those which are toxic, corrosive, ignitable, reactive, strong sensitizers, or which generate pressure through decomposition, heat or other means, which may cause, or contribute to an increase in mortality or an increase in serious irreversible or incapacitating reversible illness, taking into account the toxicity of such waste, its persistence and degradability in nature, and its potential for assimilation, or concentration in tissue, and other factors that may otherwise cause or contribute to adverse acute or chronic effects on the health of persons or other living organisms, or any matter which may have an unusually destructive effect on water quality if discharged to ground or surface waters of the state. All special nuclear, source or by-product material, as defined by the Atomic Energy Act of 1954 and amendments thereto, codified in 42 U.S.C Section 2014, is specifically excluded from this definition.


the study of groundwater, including its origin, occurrence, movement, and quality.

Light Nonaqueous Phase Liquid (LNAPL):

liquids (generally organic) that have low aqueous solubilities (they are immiscible) and have less density than water (they will float on water). They are characterized by their component composition, density, viscosity, and interfacial tension with water. Common LNAPLs include petroleum products such as gasoline, diesel fuel, and home heating oil.

Non-aqueous phase liquid (NAPL):

Non-aqueous phase liquids are liquids that are sparingly soluble in water. Because they do not mix with water, they form a separate phase. For example, oil is an NAPL because it does not mix with water, and oil and water in a glass will separate into two separate phases. NAPLs can be lighter than water (LNAPL) or denser than water ( DNAPL). Hydrocarbons, such as oil and gasoline, and chlorinated solvents, such as trichloroethylene, are examples of NAPLs. (as defined by the United States Geological Study).

Natural Attenuation:

an in-situ approach to cleanup that uses natural processes to contain the spread of contamination from chemical spills and reduce the concentrations and amounts of pollutants in contaminated soil and groundwater. Natural subsurface processes, such as dilution, volatilization, biodegradation, adsorption, and chemical reactions with subsurface materials, are allowed to reduce concentrations of contaminants to acceptable levels.

Potentially Responsible Party (PRP):

h2>Any person, potentially liable, which may include, but is not necessarily limited to, an individual or organization, including owners, operators, transporters, or generators, who is potentially responsible for or contributed to contamination at a site.

Product sheen:

A layer of light non-aqueous phase liquid (LNAPL) that is too thin to measure but is visible on top of water.

Redevelopment of Contaminated Properties Program (RCPP):

a property cleanup program which enables certain interested parties to request assistance of the secretary in reviewing and overseeing work plans to investigate, abate, remove, remediate and monitor vacant, abandoned, or substantially underutilized properties in exchange for protection from certain liabilities.


any intentional or unintentional action or omission resulting in the spilling, leaking, pumping, pouring, emitting, emptying, dumping, or disposing of hazardous materials into the surface or groundwaters, or onto the lands in the state, or into waters outside the jurisdiction of the state when damage may result to the public health, lands, waters or natural resources within the jurisdiction of the state.

Resource Conservation and Recovery Act (RCRA):

A Federal law enacted in 1976 that established a regulatory system to track hazardous substances from their generation to their disposal. The law requires the use of safe and secure procedures in treating, transporting , storing, and disposing of hazardous substances. RCRA is designed to prevent the creation of new, uncontrolled hazardous waste sites.

Sensitive Receptors:

Areas which may be affected by a release of a hazardous material. These may include public or private water supplies; surface waters; wetlands; sensitive ecological areas, outdoor and indoor air; and enclosed spaces such as basements, sewers, and utility corridors.

Standard Operating Procedures (SOPs):

A detailed set of instructions for performance of a specific, discrete task. It should identify the necessary equipment and provide step-by-step instructions for performance of a task. It needs to be written clearly and unambiguously so that the task described will be performed the same way regardless of who is performing the task. SOPs are commonly developed for many hazardous site investigation activities, including sample collection, decontamination, and field screening techniques.

Underground Storage Tank (UST):

UST means any one or combination of tanks including underground pipes connected to it or them, which is or has been used to contain an accumulation of regulated substances, and the volume of which, including the volume of the underground pipes connected to it or them, is 10 percent or more beneath the surface of the ground.