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glossary of the great lakespage
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Half-Life
Hazardous Air Pollutants HAPs
Hazardous Waste
Heavy Metals
Hexachlorobenzene HCB
House Great Lakes Task Force
Human Health Criteria
Hydric Soils
Hydrocarbons
Hydrophytic Vegetation

Half-Life
The period of time necessary for one half of a substance introduced to a living system or ecosystem to be eliminated or disintegrated by natural processes.

Hazardous Air Pollutants HAPs
Any air pollutant listed as such in Title III of the 1990 Clean Air Act Amendments. These are chemicals that have the potential to cause serious health effects. HAPs are released by mobile sources and industrial sources. Also referred to as air toxics. Related Programs - Clean Air Act

Hazardous Waste
A waste which, because of its quantity, concentration, or characteristics, may be hazardous to human health or the environment when improperly treated, stored, transported, or disposed. Specific definitions of hazardous waste vary by statute or regulation.

Heavy Metals
Metallic elements with relatively high atomic weights that can contaminate groundwater and surface waters, wildlife, and food. Heavy metals have the potential to be toxic at relatively low concentrations. Examples include arsenic, cadmium, chromium, copper, lead, mercury, selenium, and zinc.

Hexachlorobenzene HCB
A critical pollutant once used as a pesticide for grain protection until banned by the U.S. in 1976. It is still produced as a byproduct during the manufacture of other chlorinated hydrocarbons. It is a persistent toxic substance and is found in the tissues of fish, animals, and humans from the Great Lakes Basin. Limited uses of HCB are still permitted. Related Programs - Binational Program

House Great Lakes Task Force
A bipartisan coalition of U.S. Representatives from Great Lakes States that works to advance the economic and environmental health of the Great Lakes region.

Human Health Criteria
These are descriptive or numeric expressions that specify how much of a pollutant can be allowed in a water body and still allow for the protection of human health. See also water quality criteria. Related Programs - Great Lakes Initiative

Hydric Soils
Soils that are saturated, flooded, or ponded long enough during the growing season to develop anoxic conditions in the upper part of the soil profile.

Hydrocarbons
A class of compounds that contain hydrogen and carbon. This group of compounds includes the naturally occurring hydrocarbons produced by plankton, as well as many petroleum-based products like gasoline and motor oil. Chlorinated hydrocarbons, a subclass of hydrocarbons, are human derived and generally toxic.

Hydrophytic Vegetation
Plant life capable of growing in wet conditions, such as in water or in soil or other substrate that is periodically saturated with water. The presence of hydrophytic plants is one of the indicators used in wetland identification and delineation. Related Programs - Wetlands Conservation Act, Wetlands Conservation Act Rules.

 

 

 

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 www.seagrant.umn.edu /pubs/ggl/h.html modified December 4, 2012