Sources of Coastal Pollution
Pollution sources are classified as point sources or non-point
sources by the US Environmental Protection Agency. Information about
pollution sources is included in their Fact
Point sources are:
Any discernible, confined, and discrete conveyance,
including but not limited to, any pipe, ditch, channel, tunnel, conduit,
well, discrete fissure, container, rolling stock concentrated animal
feeding operation (CAFO), landfill leachate collection system, vessel
or other floating craft from which pollutants are or may be discharged.
This term does not include return flows from irrigated agriculture
or agricultural storm water runoff.
Point sources generally enter receiving water
bodies at some identifiable site(s) and carry pollutants whose generation
is controlled by some internal process or activity, rather than weather.
From US Environmental Protection Agency National
Management Measures to Control Nonpoint Source Pollution from Agriculture.
Point sources include combined
sewer overflows, concentrated
animal feeding operations, sanitary
sewer overflows, storm
water, oil spills, industrial
discharges; discharge from boats, and dumping of ballast water
Wisconsin Feedlot. The soil is wet from
rain, urine, and manure. and it is a rich source of bacterial, viral,
and nutrient pollution.
From Clean Water Action Council
of Northeastern Wisconsin, Inc.
Nonpoint source pollution generally results
from land runoff, precipitation, atmospheric deposition, drainage,
seepage, or hydrologic modification. Technically, the term "nonpoint
source" is defined to mean any source of water pollution that
does not meet the legal definition of "point source" in
section 502(14) of the Clean Water Act.
Polluted Runoff Background Paper.
- Runoff from farm lands and managed forestsin the coastal zone that
carry fertilizer, excess nutrients, pesticides and
herbicides, salts in
irrigation water, and crop residues.
- Runoff from agricultural areas (excluding concentrated animal feeding
operations) that carries nutrients, animal
wastes, manure, and pathogens (bacteria and viruses).
- Runoff from coastal cities that carry trash, litter, heavy metals,
carbon-based chemicals such as oil from highways, fertilizer and pet
waste from backyards and sidewalks, and detergent
(the most common pollutant).
Trash from land carried into the ocean by
rains. Click on image for a zoom.
Taylor, Synthesis Magazine.
Hydromodification is one of the leading sources of impairment in streams,
lakes, estuaries, aquifers, and other water bodies in the United States.
Three major types of hydromodification activities change a waterbody's
physical structure as well as its natural function. These changes can
cause problems such as changes in flow, increased sedimentation, higher
water temperature, lower dissolved oxygen, degradation of aquatic habitat
structure, loss of fish and other aquatic populations, and decreased
water quality. The changes are:
- Channelization and channel modification, including cutting
new channels through barier islands, or closing such channels.
- Stream bank and shoreline erosion.
- Marinas and
Marina Del Rey, California, a coastal lagoon
turned into urban development and marinas.The area was originally known
Lagoon. Click on image for a zoom.
Perry, California State University Long Beach.
Rancho La Ballona was characterized by two great
creeks; Ballona Creek running from the east to west and creating a great
lagoon and Centinela Creek running from the northern hills to Ballona
Creek ... As the 19th century came to a close, La Ballona was considered
a “swamp” and
the only activity occurred at the mouth of Ballona Creek where the squatter
Will Tell opened a sea shore retreat that would “furnish sportsmen
with board and lodging for man and beast.”
From Del Rey Neighborhood
- Atmospheric deposition of sediments and chemicals carried by the
- Mercury in water comes mostly from the atmosphere.
- 55% of mercury emissions are natural, from volcanoes and forest
- 42% are man made outside the USA.
- 1% come from US power plant emissions.
- Under some conditions, excess sand, silt, and clays (sediments)
eroded from land, especially land denuded of plants that hold sediments.
Mostly, sediments are needed by the coastal zone. Excess sediments
that bury plants, or sediments in water that is historically sediment
free, such as water near coral reefs, are pollutants.
- Groundwater discharge which can include all types of pollutants,
including water from faulty septic systems.
- Solvents used to clean boats, anti-fowling agents leached from hulls.
Anti-fowling agents are designed to be highly toxic to marine life
that settles on to hard surfaces.
- Trash dumped from ships, dropped on beaches, and washed into the
The most common sources of bacterial pollution at beaches
and near-shore waters are:
- Unknown, very few governmental agencies track the source of pollution
on their beaches.
- Runoff from land, including urban areas and intensive farming operations.
Runoff from urban lawns and streets contains waste from millions of
pets. Pollution is greatest from areas with the largest percentage
of impervious surfaces (roofs, paved streets and parking lots). A
study conducted in South Carolina found that a watershed that was 22
percent covered by impervious surfaces had an average fecal coliform
count seven times higher than a watershed that was 7 percent covered
by impervious surfaces (Mallin, 2006).
- Sewage spills and overflows, including spills caused by heavy rains
overloading combined sewage systems (combination of street drains and
- Boat spills and wildlife, although these are not very important.
Sources of bacterial pollution causing 25,643 days of beach closings
at US vacation beaches in 2006.
From Testing the Waters: A Guide to Water Quality at Vacation Beaches
by the Natural Resources Defense Council
Read this United States Geological Survey fact Sheet on Nitrogen
in the Mississippi Basin-Estimating Sources and Predicting Flux to
the Gulf of Mexico.
What Can I Do?
The Coastal Waccamaw Storm water Education Consortium has useful
Good water quality depends on us, and we depend
on good water quality. And ensuring good water quality starts with
individuals like you! There are many things that you can do around
your home and in your everyday life to help manage storm water and
control nonpoint source pollution in order to protect water quality.
Consider the impact on our local waters if everyone took these simple
- Remember, storm drains lead to the rivers, which lead to the sea.
Never put anything into a storm drain.
- Pet owners should pick up after their pets and dispose of pet waste
in the garbage.
- Don't litter.
- Plant rain gardens, vegetated buffers, and maintain vegetation.
- Properly maintain your septic system.
- Maintain your car to prevent oil and fluid leaks.
- Wash your car at a car wash or over the grass to prevent the soap
and wash water from flowing into nearby storm drains.
- Use fertilizers and pesticides sparingly and only as directed. Consider
organic, non-toxic alternatives to these chemicals.
- Do not allow yard waste such as leaves and grass clippings to blow
into gutters or onto paved surfaces to be washed into storm drains.
- Report erosion and sediment problems from construction sites.
- Minimize impervious surfaces.
- Get involved in local river and beach clean ups, and other projects
that help protect water quality.
The city of Decatur, Illinois has a web page, You
Can Help, that lists ways to reduce water pollution. Humbolt County
California points out that for their citizens, Humbolt
Bay Starts on Your Street.
Worth maintains a web site listing sources of urban pollution,
and how the city is reducing the pollution.
Worth Detergent is our Number One Pollutant
Dorfman, M. and N. Stoner (2007). Testing the Water: A Guide to Water
Quality at Vacation Beaches, Natural Resources Defense Council: 375.
Mallin, M. A. (2006). Wading in Waste. Scientific American: 53--59.
15 April, 2009