PAHs
See Polycyclic Aromatic Hydrocarbons.

Part 70 Permit
A federal regulation that defines the requirements for permitting facilities for air emissions. States with federally-approved permit programs administer the permitting of facilities within their state. Related Programs - Minnesota Rule Chapter 7007, 1990 Clean Air Act Amendments

Particulates
Very small separate particles composed of organic or inorganic matter.

Parts per Billion ppb
The number of parts of a substance per billion parts of another substance into which it is combined. Often expressed as micrograms per liter for water and micrograms/kilogram for fish and sediments.

Parts per Million ppm
The number of parts of a substance per million parts of another substance into which it is combined. Often expressed as milligrams/liter water or milligrams/kilogram for fish tissue and sediments.

Parts per Thousand ppt
The number of parts of a substance per thousands parts of another substance into which it is combined. Often expressed as grams/liter of water or grams/kilogram for fish tissue and sediments.

Periphyton
Algae that grow attached to surfaces such as rocks or larger plants.

Persistent Toxic Substance
A toxic pollutant that remains in the environment for a substantial period of time, potentially causing injury to ecosystem health.

pH
A numeric value that indicates relative acidity and alkalinity on a scale of 1 to 14. A pH of 7.0 is neutral, higher values indicate increasing alkalinity; lower values indicate increasing acidity.

Phytoplankton
Algae that grow suspended in the water column or open waters of a lake.

Plankton
A term used to describe bacteria, tiny plants (phytoplankton) and animals (zooplankton) that live in the water column of lakes.

Point Source
See point source pollution.

Point Source Pollution
Pollution from a distinct, identifiable source, such as a pipe, smokestack, or exhaust.

Pollutant
Chemicals or refuse material released into the atmosphere or water or onto the land.

Pollution Prevention P2
This is defined in the Minnesota Toxic Pollution Prevention Act as eliminating or reducing at the source the use, generation, or release of toxic pollutants. Methods of reducing pollution include, but are not limited to, industrial process modification, inventory control measures, feedstock substitutions, various housekeeping and management practices, and improved efficiency of machinery. The federal version of this term is source reduction.

Pollution Prevention Act of 1990
A federal law that establishes a national policy of pollution prevention, and requires the EPA to develop and implement a strategy to promote source reduction. This act declares as national policy that pollution prevention is the preferred approach to environmental protection.

Polychlorinated Biphenyls PCBs
One of the nine critical pollutants, PCBs are a group of over 200 nonflammable compounds formerly used in heating and cooling equipment, electrical insulation, hydraulic and lubricating fluids, and various inks, adhesives, and paints. These compounds are highly toxic to aquatic life, persist in the environment for long periods of time, and are bioaccumulative. PCBs are suspected carcinogens, and are linked to infant development problems. Fish from some lakes and streams in Minnesota contain measurable amounts of PCBs. See also Fish Consumption Advisory. Related Program - Binational Program

Polycyclic Aromatic Hydrocarbons PAHs
A family of organic chemicals based on the chemical structure of benzene which result from incomplete combustion of organic chemicals and are associated with grease and other components derived from petroleum byproducts. Some examples of the many PAH compounds include; benz(a)anthracene, beno(b)fluoranthene, benzo(a)pyrene, chrysene, phenanthrene, and pyrene.

Pretreatment
Partial wastewater treatment required for some industries. Pretreatment removes some types of industrial pollutants before the wastewater is discharged to a municipal wastewater treatment plant.

Primary Productivity
The amount of production of living organic material through photosynthesis by plants, including algae, measured over a period of time.

Primary Treatment
The first step in wastewater treatment in which most of the debris and solids are removed mechanically.

Priority Pollutants
Pollutants identified in certain federal and state regulations. Priority pollutants have different definitions in air, water, and waste programs.

Program Office
See Great Lakes National Program Office.

Protected Waters
Minnesota Waters of the State identified as public waters or wetlands under MN Statutes.

Public Waters
Generally, public waters are water bodies determined by Minnesota statutes to have significant public value. They are controlled by the state (103G.005).

Public Waters Wetlands
A class of wetlands defined by the state of Minnesota as public waters deserving of a certain level of protection under the Wetland Conservation Act. These include all Types 3, 4, and 5 wetlands, as defined in U.S. Fish and Wildlife Service Circular No. 39 (1971 edition), that are ten or more acres in size in unincorporated areas, or 2-1/2 or more acres in size in incorporated areas.

Publicly Owned Treatment Works POTW
Any device or system that is used in treatment, including recycling and reclamation, of municipal sewage. Related Program - Clean Water Act, 40 CFR

Purple Loosestrife
A wetland plant from Eurasia that quickly invades water bodies, including the Great Lakes, forming dense stands unsuitable as cover, food, or nesting sites for fish, amphibians, waterfowl and wildlife. Imported as an ornamental plant, it spread quickly across North America along roads, canals and drainage ditches. Research on the use of European beetles that attack only purple loosestrife shows promise for biological control in North America.