Regulators divide the source of unwanted pollutants going into our waterways into two broad categories—point source and nonpoint source (NPS) pollution.
Industrial and sewage treatment facilities are examples of point sources of pollution. The U.S. EPA has historically focused on point sources of pollution. Now it is widening its focus to include NPS pollutants as it works with states to develop and implement “pollution diets” to reduce the amount of nutrients entering our nation’s waterways.
The landscape and lawn care industries are increasingly being scrutinized as contributing to NPS pollution.
NPS generally results from land runoff, precipitation, atmospheric deposition, drainage or seepage. NPS is caused by rainfall or snowmelt moving over and through the ground. As the runoff moves, it picks up and carries away natural and human-made pollutants, finally depositing them into lakes, rivers, wetlands, coastal waters and ground waters.
NPS pollution can include:
- Excess fertilizers, herbicides and insecticides from agricultural lands and residential areas;
- Oil, grease and toxic chemicals from urban runoff and energy production;
- Sediment from improperly managed construction sites, crop and forest lands and eroding stream banks;
- Salt from irrigation practices and acid drainage from abandoned mines; and
- Bacteria and nutrients from livestock, pet wastes and faulty septic systems.