Occurring over a short time [compare with chronic].
Agency for Toxic Substances and Disease Registry (ATSDR):
The principal federal public health agency involved with hazardous waste
issues, responsible for preventing or reducing the harmful effects of exposure
to hazardous substances on human health and quality of life. ATSDR is part
of the U.S. Department of Health and Human Services.
Chronic:
Occurring over a long time (more than 1 year) [compare with acute].
Contaminant:
A substance that is either present in an environment where it does not
belong or is present at levels that might cause harmful (adverse) health
effects.
Dermal Contact:
Contact with (touching) the skin (see route of exposure).
Environmental Protection Agency (EPA):
United States Environmental Protection Agency.
Exposure:
Contact with a substance by swallowing, breathing, or touching the skin
or eyes. Exposure may be short-term [acute exposure], of
intermediate duration, or long-term [chronic exposure].
Groundwater:
Water beneath the earth's surface in the spaces between soil particles
and between rock surfaces [compare with surface water].
Hazardous substance:
Any material that poses a threat to public health and/or the environment.
Typical hazardous substances are materials that are toxic, corrosive, ignitable,
explosive, or chemically reactive.
Ingestion:
The act of swallowing something through eating, drinking, or mouthing
objects. A hazardous substance can enter the body this way [see route of
exposure].
Ingestion rate:
The amount of an environmental medium that could be ingested typically
on a daily basis. Units for IR are usually liter/day for water, and mg/day
for soil.
Inhalation:
The act of breathing. A hazardous substance can enter the body this way
[see route of exposure].
Organic:
Compounds composed of carbon, including materials such as solvents, oils,
and pesticides that are not easily dissolved in water.
Plume:
A volume of a substance that moves from its source to places farther away
from the source. Plumes can be described by the volume of air or water they
occupy and the direction they move. For example, a plume can be a column
of smoke from a chimney or a substance moving with groundwater.
Route of exposure:
The way people come into contact with a hazardous substance. Three routes
of exposure are breathing [inhalation], eating or drinking [ingestion],
or contact with the skin [dermal contact].
Volatile organic compound (VOC):
Organic compounds that evaporate readily into the air. VOCs include substances
such as benzene, toluene, methylene chloride, and methyl chloroform.
