Key Terms

ACGIH - American Conference of Governmental & Industrial Hygienists.

Acute effects - Effects that occur shortly after exposure to a chemical or other toxic agents.

Aquifer - Underground stratum (layer) of porous material containing water (groundwater), which may be withdrawn from wells for use.

Asbestos - One of several naturally occurring silicate fibers. Useful in society as an insulator but deadly to breathe even in small amounts.

Asbestosis - Lung disease characterized by a buildup of scar tissue in the lungs, caused by the inhalation of asbestos.

ATSDR - Agency for Toxic Substances & Disease Registry, U.S. Dept. of Health & Human Services.

BACT - Best Available Control Technology.

Bioaccumulation - Refers to the buildup of chemicals within tissues and organs of the body and results factors a resistance to breakdown and slow excretion rates.

Biochemical oxygen demand (BOD) - Measue of oxygen depletion of water, largely from bacterial decay, due to the presence of biodegradable organic pollutants. Gives scientists an indication of how much organic matter is in water.

CERCLA - Comprehensive Environmental Response, Compensation, and Liability Act (Superfund).

CFC - Chlorofluorocarbons.

Chronic effects - Delayed effects resulting from exposure to chemicals or other toxic agents.

COD - Chemical Oxygen Demand.

DDT - Dichlorodiphenyltrichloroethane.

Environment - All of the biological and nonbiological factors that affect an organism's life.

EIS - Environmental Impact Statement.

EPA - U.S. Environmental Protection Agency.

Epidemiology - Study of disease and death in human populations, which attempts to find links between causes and effects through statistical methods.

FIFRA - Federal Insecticide, Fungicide, and Rodenticide Act.

Indoor air pollution - Air pollutants in homes from internal sources such as smokers, fireplaces, wood stoves, carpets, paneling, furniture, foam insulation, paint, adhesives, and cooking stoves.

Landfill - Depression in the ground or excavated site in which waste is deposited. Sanitary landfills are so named because trash is covered daily with soil to prevent odors and proliferatin of rodents and flies. Can be used for hazardous waste. Must be lined with clay and impermeable liners to accept hazardous material.

LD 50 - Lethal Dose for 50% of the population exposed to a solid or liquid substance.

LC 50 - Lethal Concentration for 50% of the population exposed to a substance in the air.

Metastasis - Movement of cancer cells to another location where new tumors are formed.

Mutagen - A chemical or physical agent capable of damaging the genetic material (DNA and chromosomes) of living organisms in both germ cells and somatic cells.

NIOSH - National Institute for Occupational Safety and Health, U.S. Dept. of Health and Human Services.

NPL - National Priority List of Superfund sites.

OSHA - Occupation Safety & Health Administration or Act.

Ozone (O 3 ) - Inorganic molecule found in the lower atmosphere, where it is a pollutant because of its harmful effects on living tissue and rubber. Also found in the stratosphere, where it helps screen ultraviolet light. Used in some advanced sewage treatment plants.

PCBs - Polychlorinated Biphenyls, group of at least 50 organic compounds, used for many years as insulation in electrical equipment (transformers). Capable of biomagnification. Disrupts reproduction in gulls and possibly other organisms high on the food chain.

RACT - Reasonably Available Control Technology.

SARA - Superfund Amendments & Reauthorization Act.

TSCA - Toxic Substances Control Act.