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Resources |  Water Quality
Nonpoint Source Pollution

Water quality has become a major issue along the southern shores of Lake Huron in recent years.  The sources of this pollution are many, and the culprits as equally diverse.


Nonpoint-source pollution is another term for polluted runoff.  Water washing over the land, whether from precipitation, car washing or watering crops or lawns, picks up an array of contaminants including oil, sand and salt from roadways, agricultural chemicals, and nutrients and toxic materials from both urban and rural areas.


The term nonpoint is used to distinguish this type of pollution from point source pollution, which comes from specific sources such as sewage treatment plants or industrial facilities.

Nonpoint-source pollution is the cumulative result of our everyday personal actions and our local land use policies. Here’s a brief rundown on the major types of pollutants carried by runoff:


  • Pathogens

Pathogens are disease causing microorganisms, such as bacteria and viruses that come from the fecal waste of animals and humans. Pathogens wash off the land from wild animal, farm animal and pet waste, and can also enter the lake from improperly functioning septic systems, leaky sewer lines and boat sanitary disposal systems. 

  • Nutrients

Nutrients are compounds that stimulate plant growth, like nitrogen and phosphorous. In high concentrations, they can become both an environmental and health threat. Nutrients in polluted waters can come from agricultural fertilizers, septic systems, home lawn care products, and yard and animal wastes.

  • Toxic Contaminants

Toxins are substances that can harm aquatic and human life. They are created by a wide variety of human practices and products like heavy metals, pesticides and organic compounds like PCB’s. Many toxins are resistant to breakdown and tend to be passed through the food chain to be concentrated in top predators. Oil, grease and gasoline from roadways, and chemicals used in home, gardens, yards and on farm crops, are major sources of toxic contaminants.


Polluted runoff is largely the result of the way we develop, use and maintain our land. The sources are many and how we respond to clean up nonpoint-source will take the concerted efforts of everyone. Public attention is beginning to focus on this issue along Lake Huron. Making progress in cleaning up nonpoint-source pollution can begin by learning more about polluted runoff and how you can combat it in the course of your everyday decisions.

Additional Links


General information on water quality

Reducing non-point source pollution in rural areas

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