(Conservation Currents,
Northern Virginia Soil and Water Conservation District, May-June
2003)
Pollution is an undesirable change in the
physical, chemical, or biological characteristics of air, land,
or water that adversely affects the living conditions for either
humans or other living organisms. Water pollution is the
impairment of the beneficial uses of water. Water quality
can be adversely affected by direct and indirect sources. Direct
sources are fairly obvious and include such practices as dumping
waste and hazardous pollutants into streams. Indirect sources
are called nonpoint source (NPS) pollution. Stormwater runoff,
which may contain fertilizers and pesticides, soil lost from
construction sites, and oil residue washed off streets, is NPS
pollution. This type of pollution is much more difficult
to pinpoint and control.
- Sediment:
- Sediments are soil particles dislodged by precipitation
and deposited in streams, lakes, and rivers. While erosion
of soil is a naturally occurring process, accelerated erosion
from degraded streams and poor construction practices creates
excess sediment. Sediments accumulate in waterbodies and destroy
feeding grounds for aquatic life, clog fish gills, block light,
and increase water temperature.
Nutrients and Organic Debris:- Nutrients are essential to water life, but too much can
harm more than help. Phosphorous, nitrogen, and potassium
are nutrients that help plants and animals grow. Found in
fertilizer, leaves, grass clippings, sewage, detergents, and
animal wastes, these elements are not harmful to the environment
in low doses. However, excess nutrients in an already healthy
environment can be dangerous. Decaying organic matter depletes
oxygen needed by aquatic life, leaving fish and shellfish
to suffocate.
Trash: - Garbage, construction debris, and animal waste become part
of the runoff entering storm drains and local waterways and
clogging the system.
Toxins:- Toxins are chemicals that can cause human and wildlife health
problems. They include organic chemicals and metals, pesticides,
herbicides, household chemicals, paint, paint cleaners, gasoline,
motor oil, battery acid, antifreeze, and roadway salt.
Pathogens:- A pathogen is a specific causative agent of disease. The
presence of bacteria in water, which normally are found in
the intestinal tracts of humans and animals, signals that
pathogens may be present.
-
- Limit use of pesticides and fertilizer and use them at
appropriate times of the year in recommended amounts. Introduce
natural predators to your garden, and use pest resistant plants.
Remove eggs, larvae, cocoons, and adults from plants by hand.
- Prevent property erosion by covering bare soil with vegetation
and mulch.
- Participate in a stream cleanup program.
- Remove obstructions from stream channels and revegetate
stream banks.
- Don’t mow all the way to the edge of a lake or pond.
Leave a buffer of tall grasses or shrubs to filter pollutants.
- Landscape yards to minimize rainwater runoff.
- Preserve neighborhood trees that help minimize the damage
caused by surface runoff.
- Place retaining walls or diversions on steeply sloping ground
to reduce the rate of water flow and erosion.
- Make sure septic tanks work properly.
- Dispose of litter in garbage cans or in recycling bins.
Recycle glass, aluminum, plastic, paper, motor oil, and newspapers.
- Compost yard and garden waste.
- Pick up pet waste and bag it with regular household trash
or flush it in the toilet.
- And, never ever intentionally dump anything into a storm
drain!
Read more about nonpoint
source pollution and water quality.
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