Environmental Terms and Definitions

National Toxicology Program (NTP)
NTP, part of the U.S. Department of Health and Human Services (DHHS), coordinates the toxicology research being conducted within DHHS.

World Health Organization (WHO)
WHO, an agency of the United Nations, carries out public and environmental health programs throughout the world.

ADI
Acceptable Daily Intake

acute health effect
Health effects that usually occur rapidly as a result of short-term exposures, and are of short duration. Some examples are irritation, corrosivity (tissue destruction), narcosis, and death

Maximum Contaminant Level (MCL)
The highest (maximum) level of a contaminant allowed to go uncorrected by a public water system under federal or state regulations. Depending on the contaminant, allowable levels might be calculated as an average over time, or might be based on individual test results.

Interim Remedial Measure (IRM)
An action taken at a contaminated site to reduce the chances of human or environmental exposure to site contaminants. Interim remedial measures are planned and carried out before comprehensive remedial studies.

Agricultural pollution
The liquid and solid wastes from farming, including, runoff from pesticides, fertilizers, and feed- lots; erosion and dust from plowing; animal manure and carcasses, crop residues, and debris.

Ingestion
Swallowing (such as eating or drinking). Chemicals in or on food, drink, utensils, cigarettes, hands, etc. can be ingested. After ingestion, chemicals may be absorbed into the blood and distributed throughout the body.

IDLH
Immediately dangerous to life and health. Used to determine selection of a respirator. The maximum concentration from which one could escape within 30 minutes without any escape-impairing symptoms or irreversible health effects. Also, IDLH conditions and conditions that would lead to an IDLH 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.