Coastal
A-Z
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Non
Point Source Pollution: What It Is
Non-point
source (NPS) pollution, unlike pollution from industrial and
sewage treatment plants (which are discrete sources), comes from
many diffuse sources. NPS pollution is caused by rainfall, snowmelt
or other runoff 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 even our under ground sources of drinking
water. These pollutants 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 streambanks
- Bacteria and nutrients from livestock, pet wastes, and
faulty septic systems
- Salt from irrigation practices and acid drainage from
abandoned mines
- Atmospheric deposition and hydromodification are also
sources of NPS pollution
NPS pollution can come from both rural and urban areas. In rural
areas, the causes tend to be primarily large-scale changes to
the landscape, land use and hydrology caused by such operations
agriculture and logging. In urban areas, population densities,
combined with water-hungry non-natural landscaping and much of
the rest of the land covered by impervious surfaces causes constant
surface water flows that carry pollutants to inland water bodies
and the ocean.
What can be done to lessen NPS pollution? For new development
and significant redevelopment, we can design smarter to use less
water, generate less runoff, and retain and reuse runoff water
that is generated. We can use landscaping that requires less
water, fertilizers, and other chemicals.
On a personal basis, we can all do things like:
- avoid over-watering and excess chemical use
- wash your car at a car wash or at a location where the
excess water is absorbed into the ground
- fix your car leaks
- pick up after your pet
- don't litter
- recycle and reuse
- use a broom, not a hose
- plant (appropriately), don't pave
These and other tips on how to reduce NPS pollution and keep
our oceans and beaches clean, can be found in Surfrider Foundation's
brochure 20 Ways to Cleaner Oceans, Waves and Beaches
Another source of information is EPA's NPS web site
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