Aquifer: A water-saturated underground formation or geologic unit composed of materials such as sand, soil, gravel or rock that can store and supply groundwater in significant quantities.

Groundwater: Underground water that fills pores in soils or openings in rocks to the point of saturation. In aquifers, groundwater occurs in sufficient quantities for use as drinking and irrigation water and other purposes.

Groundwater Surface Water Interface (GSI) Criteria: Identifies a groundwater concentration that is protective of a receiving surface water, in situations where groundwater is discharging to surface water bodies.

Industrial Direct Contact Criteria: Identifies a soil concentration which is protective against adverse health effects due to long-term ingestion of and dermal (skin) exposure to contaminated soil for industrial land uses.

Natural Resources and Environmental Protection Act (NREPA), PA 451 of 1994, as amended: An act to protect the environment and natural resources of the state. On January 18, 1994, all laws relating to the environment and natural resources of the state were revised, consolidated and arranged as "Parts" under and by the authority of this one single law.

Part 31: Part 31 (Water Resources Protection) provides for the protection of the waters of Michigan by controlling the discharge of wastes and wastewater to the ground, groundwater and surface waters of the state.

Part 201: Part 201 (Environmental Remediation) of NREPA and its administrative rules provide for the identification, risk assessment, evaluation and cleanup of sites of environmental contamination in the state.

Residential Drinking Water Criteria: Identifies a drinking water concentration that is safe for long-term, daily residential consumption. Adverse aesthetic impacts are taken into account for select hazardous substances.

Residential Direct Contact Criteria: Identifies a soil concentration that is protective against adverse health effects due to long-term ingestion of and dermal (skin) exposure to contaminated soil for residential land uses.

Soil Criteria Protective of Residential Drinking Water: Identifies a soil concentration that is not expected to leach and contaminate groundwater at levels greater than residential drinking water criteria.

Soil Vapor Extraction (SVE): Also known as "soil venting" or "vacuum extraction", is a technology that reduces concentrations of volatile constituents in petroleum products adsorbed to soils in the unsaturated (vadose) zone. In this technology, a vacuum is applied through wells near the source of contamination in the soil. Volatile constituents of the contaminant mass "evaporate" and the vapors are drawn toward the extraction wells. Extracted vapor is then treated as necessary (commonly with carbon adsorption) before being released to the atmosphere.