Environmental Terms and Definitions

ADI
Acceptable Daily Intake

Marsh
A type of wetland that does not accumulate appreciable peat deposits and is dominated by herbaceous vegetation.Marshes may be either fresh or saltwater and tidal or non-tidal.(See: wetlands).

Activated sludge
An aerobic biological process for conversion of soluble organic matter to solid biomass, removable by gravity or filtration.

Aerobic treatment
Process by which microbes decompose complex organic compounds in the presence of oxygen and use the liberated energy for reproduction and growth. Types of aerobic processes include extended aeration, trickling filtration, and rotating biological contactors.

Superfund (federal and state)
The federal and state programs to investigate and clean up inactive hazardous waste sites.

National Institute for Occupational Safety and Health (NIOSH)
NIOSH, part of the Centers for Disease Control, conducts research on worker safety and health and recommends standards for worker protection to OSHA. For example, NIOSH recommends guidelines for workplace exposure to hazardous substances and has published criteria documents on many chemicals.

ACM
Asbestos-Containing Material

AHERA
Asbestos Hazard Emergency Response Act (1986); federal law requiring LEAs to identify asbestos hazards and develop abatement plans.

Route of exposure
The way in which a person may contact a chemical substance. For example, drinking (ingestion) and bathing (skin contact) are two different routes of exposure to contaminants that may be found in water. See "Exposure".

Action level
The exposure level (the material's concentration in air) at which OSHA regulations to protect employees take effect (29 CFR 1910.1001-1047); e.g., workplace air analysis employee training, medical monitoring, and record keeping.