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What Are the Trends in Coastal Water Quality?
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Lake Erie, Pennsylvania |
>The Ocean of the Mid-Atlantic
The
quality of the ocean along the east coast of the United States is highly
impacted by human activity. A great percentage of our population lives
within 50 miles of the coast and much of the land along the coast has
been developed. Water testing shows that the ocean of the Mid-Atlantic
is highly affected by the flow into the ocean from the Hudson River, the
Delaware River, and the Chesapeake Bay (click here
for a map). Water that falls on land can make its way to streams and
rivers that empty into the ocean, carrying pollutants, such as fertilizers
and pesticides from farms and homes. Pollution of the ocean also comes
from:
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Rainfall directly into the ocean that can carry particulates and other pollutants.
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Sewage treatment plants, combined sewer overflows, and storm drains that discharge liquid waste directly into the ocean through pipelines.
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Dumping of materials dredged from the bottoms of rivers and harbors, and waste from fish processing plants.
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Legal and illegal dumping of wastes from ships.
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Groundwater from coastal areas flowing through the sandy soil into the ocean carrying pollutants with it.
Along the east coast, some indicators of water quality show improvement, while others indicate worsening conditions. Overall, the long-term trend is for increasing loads of contaminants in the ocean caused by an ever increasing population impacting the coastal area.
Improving:
+ light penetration / water is getting clearer
+ dissolved oxygen in the bottom waters is increasing
+ heavy metals and pesticide levels
are decreasing
Getting
Worse:
- dissolved inorganic nitrogen is increasing
- dissolved inorganic phosphorus is increasing
- crab populations are decreasing
- the amount of fish caught by commercial fishermen is decreasing
combined sewer overflows = In some areas wastewater from homes and businesses is combined with stormwater runoff. Normally the water goes to a wastewater treatment plant for treatment before it is discharged. But, during major storms, the amount of water may be too much for the system to handle. During those times, some of the wastewater is discharged untreated through a pipe into a river or ocean. Combined sewer overflows often contain high levels of suspended solids, pathogenic microorganisms, toxic pollutants, floatables, nutrients, oxygen-demanding organic compounds, oil and grease, and other pollutants.
heavy metal = A common hazardous waste; can damage organisms at low concentrations and tends to accumulate in the food chain.
Lake Erie
For information on Lake Erie, go to EPA's Great Lakes Program.
LINK