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Glossary of technical terms
    that appear in the LaMPs

Acronyms | Words and definitions

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The breakdown of complex organic substances into more simple organic chemicals or substances. The ultimate product of decomposition in an aerobic environment is carbon dioxide.


The clearing of wooded areas.


A term used in the indicators of beneficial use impairments defined by the Great Lakes Water Quality Agreement to indicate an environmental condition or state that is considered to be unacceptable or less than the condition that would exist in a healthy ecosystem. In the development of the LaMP the condition was determined after consideration of the Ecosystem Goals for Lake Ontario (Section 1.7) and the preliminary ecosystem objectives.

Designated uses

The role that a water body is slated to fulfill, such as a drinking water source. Uses are specified in water quality standards for each water body or segment, whether or not the current water quality is high enough to allow the designated use. Other typical uses of a water body include propagation of fish and wildlife, recreation, agriculture, industry, and navigation.


A class of planktonic one-celled algae with skeletons of silica. Group of microscopic algae that have rigid silica-composed cell walls. They are an important part of the food chain.

Dichlorodiphenyl trichloro-ethane, DDT

DDT, one of the six critical pollutants, was commonly used as an insecticide after World War II and is now banned in the U.S. and Canada. DDT and its metabolites are toxic pollutants with long-term persistence in soil and water. They concentrate in the fat of wildlife and humans and may disrupt the human body’s chemical system of hormones and enzymes. DDT caused eggshell thinning in a number of fish-eating birds and is associated with the mortality of embryos and sterility in wildlife, especially birds. DDT still enters the Great Lakes, probably from a number of sources including airborne transport from other countries, leakage from dumps, and the illegal use of old stocks.


Dieldrin, a critical pollutant, was used as a pesticide for veterinary uses and to control soil insects. In the U.S. and Canada, its use is now restricted to termite control. Dieldrin has a long half-life in shallow waters compared to most chlorinated organic compounds. It is acutely toxic and poses a potential carcinogenic threat to humans. This chemical enters the Great Lakes System from the air or contaminated sediments and has been detected in fish and wildlife in all of the Great Lakes.


Unwanted chemical byproducts of incineration and some industrial processes that use chlorine. Dioxins can accumulate in fish and wildlife and are suspected human carcinogens. A critical pollutant considered to be highly toxic, 2,3,7,8 tetrachlorodibenzo-p-dioxin, or TCDD, is a variant in a family of 75 chlorinated organic compounds referred to as dioxins. An unwanted chemical byproduct of incineration and some industrial processes that use chlorine, dioxin tends to accumulate in the fatty tissue of fish. Dioxin is a suspected human carcinogen.


An amphipod that is an important food source for whitefish, lake trout, and smelt, has declined dramatically in the eastern Great Lakes basin due to impacts from the quagga mussel.


Any release or unloading of a substance or materials from a pipe, or other emission source. The addition of any pollutant to the waters of the state or to any disposal system from a point source.

Discharge of Dredged or Fill Material

Any addition of dredged or fill material into navigable waters or into the waters of the United States. This includes the driving of pilings and the addition of any material that changes the bottom elevation or configuration of a water body or material that might destroy or degrade any navigable water.

Dissolved oxygen

The amount of oxygen measured in the water.

Dry Deposition

The deposition of pollutants from the atmosphere (such as dust and particulate matter) that occurs during dry weather periods. Dry deposition rates are often drastically different than wet deposition rates.

Duluth-Superior Port Plan

A local program where the MN DNR is required to establish a port plan before it can authorize the filling of protected waters for port development. The plan includes provisions to protect designated natural resources areas, and to adopt a policy of no net loss for wetlands, fish habitat, and aquatic communities in the St. Louis River and Estuary.

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