Remediation Glossary
Below is a list of terms commonly used in relation to general environmental remediation efforts that can be found throughout this website.

1, 4-Dioxane — A clear, flammable liquid mainly used as an industrial solvent during a variety of manufacturing processes including electronics, metal finishing, fabric cleaning, pharmaceuticals, herbicides, pesticides, antifreeze, paper, etc. It is also found in household products such as detergents, shampoos, body lotions, dishwashing soap and cosmetics.

Abandoned Well: A well whose use has been permanently discontinued or which is in a state of such disrepair that it cannot be used for its intended purpose.

Abatement: Reducing the degree or intensity of, or eliminating, pollution.

Absorption: The uptake of water , other fluids, or dissolved chemicals by a cell or an organism (as tree roots absorb dissolved nutrients in soil.)

Absorption Barrier: Any of the exchange sites of the body that permit uptake of various substances at different rates (e.g. skin, lung tissue, and gastrointestinal-tract wall).

Activated Carbon: A highly adsorbent form of carbon used to remove odors and toxic substances from liquid or gaseous emissions. In waste treatment, it is used to remove dissolved organic matter from waste drinking water. It is also used in motor vehicle evaporative control systems.

Activated Sludge: Product that results when primary effluent is mixed with bacteria-laden sludge and then agitated and aerated to promote biological treatment, speeding the breakdown of organic matter in raw sewage undergoing secondary waste treatment.

Activator: A chemical added to a pesticide to increase its activity.

Active Ingredient: In any pesticide product, the component that kills, or otherwise controls, target pests. Pesticides are regulated primarily on the basis of active ingredients.

Administrative Order: A legal document signed by a Regulatory Agency directing an individual, business, or other entity to take corrective action or refrain from an activity. It describes the violations and actions to be taken, and can be enforced in court. Such orders may be issued, for example, as a result of an administrative complaint whereby the respondent is ordered to pay a penalty for violations of a statute.

Administrative Order On Consent: A legal agreement signed by a Regulatory Agency 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.

Administrative Procedures Act: A law that spells out procedures and requirements related to the promulgation of regulations.

Administrative Record: All documents which a Regulatory Agency considered or relied on in selecting the response action at a remediation site, culminating in the record of decision for remedial action or, an action memorandum for removal actions.

Adsorption: Removal of a pollutant from air or water by collecting the pollutant on the surface of a solid material; e.g., an advanced method of treating waste in which activated carbon removes organic matter from waste-water.

Airborne Particulates: Total suspended particulate matter found in the atmosphere as solid particles or liquid droplets. Chemical composition of particulates varies widely, depending on location and time of year. Sources of airborne particulates include: dust, emissions from industrial processes, combustion products from the burning of wood and coal, combustion products associated with motor vehicle or non-road engine exhausts, and reactions to gases in the atmosphere.

Airborne Release: Release of any pollutant into the air.

Alachlor: A herbicide, marketed under the trade name Lasso, used mainly to control weeds in corn and soybean fields.

Alar: Trade name for daminozide, a pesticide that makes apples redder, firmer, and less likely to drop off trees before growers are ready to pick them. It is also used to a lesser extent on peanuts, tart cherries, concord grapes, and other fruits.

Algae: Simple rootless plants that grow in sunlit waters in proportion to the amount of available nutrients. They can affect water quality adversely by lowering the dissolved oxygen in the water. They are food for fish and small aquatic animals.

Algal Blooms: Sudden spurts of algal growth, which can affect water quality adversely and indicate potentially hazardous changes in local water chemistry.

Algicide: Substance or chemical used specifically to kill or control algae.

Aliquot: A measured portion of a sample taken for analysis. One or more aliquots make up a sample.

Alkaline: The condition of water or soil which contains a sufficient amount of alkali substance to raise the pH above 7.0.

Alkalinity: The capacity of bases to neutralize acids. An example is lime added to lakes to decrease acidity.

Aquifer — An underground layer of rock, sand, silt or clay that contains water. Aquifers are sources of groundwater for wells and springs.

Cap: A layer of clay, or other impermeable material installed over the top of a closed landfill to prevent entry of rainwater and minimize leachate.

CERCLIS: The federal Comprehensive Environmental Response, Compensation, and Liability Information System is a database that includes all sites which have been nominated for investigation by the Superfund program.

Chlorinated Hydrocarbons: 1. Chemicals containing only chlorine, carbon, and hydrogen. These include a class of persistent, broad-spectrum insecticides that linger in the environment and accumulate in the food chain. Among them are DDT, aldrin, dieldrin, heptachlor, chlordane, lindane, endrin, Mirex, hexachloride, and toxaphene. Other examples include TCE, used as an industrial solvent. 2. Any chlorinated organic compounds including chlorinated solvents such as dichloromethane, trichloromethylene, chloroform.

Chlorinated Solvent: An organic solvent containing chlorine atoms(e.g. methylene chloride and 1,1,1-trichloromethane). Uses of chlorinated solvents are include aerosol spray containers, in highway paint, and dry cleaning fluids.

Chlorination: The application of chlorine to drinking water, sewage, or industrial waste to disinfect or to oxidize undesirable compounds.

Chlorinated solvents- are chemicals which include methylene chloride perchloroethylene and trichloroethylene. Methylene chloride is used in pharmaceuticals, chemical processing, aerosols, food extraction, urethane foam blowing and surface treatment including paint stripping; Perchloroethylene is used for dry cleaning and metal cleaning; and Trichloroethylene is used to clean metals and in speciality adhesives.

Consent Order — A legally enforceable agreement between the Federal Department of Environmental Protection and a company requiring the company to participate in the investigation or clean-up of a contaminated site.

Dermal contact – is the process by which a chemical penetrates the skin and enters the body.

Groundwater - is the supply of water found beneath the Earth's surface, usually in soils or rock, which supply wells and springs. Because ground water is a major source of drinking water in America, there is growing concern over contamination from leaching agricultural or industrial pollutants or leaking underground storage tanks.

Hazard Index (Indices) – a number calculated in the human health risk assessment and used as a threshold criterion for those chemicals with non-cancer health effects to indicate whether or not they collectively pose a health threat. If collectively, they result in a hazard index above 1, then further study or action is recommended at the site.

Hazards Identification - means providing information on physical, chemical, and biological hazards that may be encountered at the site or while doing work at the site. Physical hazards include slip, trip, or fall hazards that the site itself or the work may cause. Chemical hazards include those toxic chemicals found at the site or used while working at that site. Biological hazards may include bites and stings from insects or other site animals, or may include biomedical wastes found at the site. Hazards identification is required by the Occupational Safety and Health Administration (OSHA) to be included in a site health and safety plan prepared prior to performing work at a hazardous waste site.

Human health risk assessments - are reports that include information about potential health impacts from exposure to chemicals found at the site.

Indoor Air: The breathable air inside a habitable structure or conveyance.

Indoor Air Pollution: Chemical, physical, or biological contaminants in indoor air.

Infiltration: 1. 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. 2. The technique of applying large volumes of waste water to land to penetrate the surface and percolate through the underlying soil. 

Infiltration Gallery: A sub-surface groundwater collection system, typically shallow in depth, constructed with open-jointed or perforated pipes that discharge collected water into a watertight chamber from which the water is pumped to treatment facilities and into the distribution system. Usually located close to streams or ponds.

Infiltration Rate: The quantity of water that can enter the soil in a specified time interval.

Inflow: Entry of extraneous rain water into a sewer system from sources other than infiltration, such as basement drains, manholes, storm drains, and street washing.

Influent: Water, wastewater, or other liquid flowing into a reservoir, basin, or treatment plant.

Injection Well: A well into which fluids are injected for purposes such as waste disposal, improving the recovery of crude oil, or solution mining.

In Situ: In its original place; unmoved unexcavated; remaining at the site or in the subsurface.

Leaching: The process by which soluble constituents are dissolved and filtered through the soil by a percolating fluid.

Maximum Contaminant Level: The maximum permissible level of a contaminant in water delivered to any user of a public system. MCLs are enforceable standards.

Monitoring: Periodic or continuous surveillance or testing to determine the level of compliance with statutory requirements and/or pollutant levels in various media or in humans, plants, and animals.

Monitoring Well: 1. A well used to obtain water quality samples or measure groundwater levels. 2. A well drilled at a hazardous waste management facility or Superfund site to collect ground-water samples for the purpose of physical, chemical, or biological analysis to determine the amounts, types, and distribution of contaminants in the groundwater beneath the site.

Organic vapors – are gases generated from organic material. Examples include methane gas from sewage or municipal trash or vapors from gasoline at the gas stations. Sometimes you can smell the vapors, while other vapors are odorless and colorless, so they are hard to detect without instruments like the photo-ionization detector (PID).

Osmosis: The passage of a liquid from a weak solution to a more concentrated solution across a semipermeable membrane that allows passage of the solvent (water) but not the dissolved solids.

Parts per Billion (ppb) — A measurement expression used to describe the concentration of a substance in air, water or soil. In water, one part per billion is roughly equal to one half teaspoon of water in an Olympic-sized pool (660,000 gallons).

Perchloroethylene - is also known as tetrachloroethylene - hence the common acronyms PCE or PERC. This chemical is a chlorinated solvent. PCE is used commercially as industrial degreasers, spot removers, and in dry cleaning.

Photo-ionization detector (PID) - is a portable instrument that detects vapors and gas using an ultraviolet lamp.

Plume — A body of contaminated groundwater moving away from its source. The movement of the groundwater is influenced by such factors as local groundwater flow patterns, the character of the aquifer in which the groundwater is contained and the thickness of contaminants.

Radius of Influence: 1. The radial distance from the center of a wellbore to the point where there is no lowering of the water table or potentiometric surface (the edge of the cone of depression); 2. the radial distance from an extraction well that has adequate air flow for effective removal of contaminants when a vacuum is applied to the extraction well.

Radon: A colorless naturally occurring, radioactive, inert gas formed by radioactive decay of radium atoms in soil or rocks.

Release: Any spilling, leaking, pumping, pouring, emitting, emptying, discharging, injecting, escaping, leaching, dumping, or disposing into the environment of a hazardous or toxic chemical or extremely hazardous substance.

Remedial Action (RA): The actual construction or implementation phase of a remediation site cleanup that follows remedial design.

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.

Remedial Investigation: An in-depth study designed to gather data needed to determine the nature and extent of contamination at a remediation site; establish site cleanup criteria; identify preliminary alternatives for remedial action; and support technical and cost analyses of alternatives. The remedial investigation is usually done with the feasibility study. Together they are usually referred to as the "RI/FS".

Remediation — Also known as cleanup, remediation is taking action to reduce, isolate or remove contamination from an environment with the goal of preventing exposure to people or animals.

Run-Off: That part of precipitation, snow melt, or irrigation water that runs off the land into streams or other surface-water. It can carry pollutants from the air and land into receiving waters.

Sediment - refers to sand, silts, and clays washed from the land into water, usually after rain or snow melt. Sediment is found under water in storm drains, ponds, lakes, creeks, streams, rivers, and oceans.

Superfund Program – or the Comprehensive Environmental Response, Compensation, and Liability Act of 1980 (CERCLA) is a United States federal law designed to clean up sites contaminated with hazardous substances and pollutants.

Surface soils – refers to the topsoil found usually within the first six inches to one foot beneath the land surface. It is assumed that people can come into contact with surface soils when doing normal activities around the home or work place, such as shallow digging for fencing, gardening, landscaping, and mowing the lawns.

Surface Water: All water bodies naturally open to the atmosphere (rivers, creeks, storm drains, lakes, reservoirs, ponds, streams, impoundments, seas, estuaries, etc.)

Threshold criteria - are the numbers designated by the EPA or state to be the benchmark below which there is no health concern and above which further study or cleanup action is recommended to address potential health problems.

Trichloroethene (Trichloroethylene, TCE) — A nonflammable, colorless liquid with a slightly sweet odor that can be found in air, soil and water. It has been used as a solvent to remove grease from metal parts and in household and consumer products such as typewriter correction fluid, paint removers, adhesives and spot removers.

Volatile Organic Compounds (VOCs) — A group of chemicals that evaporate at room temperature into the atmosphere. They often have a sharp smell and can come from many products such as office equipment, adhesives, carpeting, upholstery, paints, solvents and cleaning products.

Waste Characterization: Identification of chemical and microbiological constituents of a waste material.

Wastewater: The spent or used water from a home, community, farm, or industry that contains dissolved or suspended matter.Water Pollution: The presence in water of enough harmful or objectionable material to damage the water's quality.

Wetlands: An area that is saturated by surface or ground water with vegetation adapted for life under those soil conditions, as swamps, bogs, fens, marshes, and estuaries.