The text on this site is presented as an archival version of the script of "Ocean Planet," a 1995 Smithsonian Institution traveling exhibition. The content reflects the state of knowledge at the time of the exhibition, and has not been updated.

Around the world, untreated sewage flows into coastal waters, carrying organic waste and nutrients that can lead to oxygen depletion, as well as disease-causing bacteria and parasites that require closing beaches and shellfish beds §.

As human population grows, so will the volume of raw sewage pouring into the oceans.

Overloaded Systems

Much untreated sewage enters waterways when rainstorms overload combined storm-water and sewage systems §. In the U.S., frequent sewer overflows restrict shellfish harvests and close beaches § §.

No Systems At All

Most developing countries lack sewage collection and treatment facilities §, but some developed countries also release untreated sewage. Sewage contamination has led to outbreaks of hepatitis A and cholera throughout the world §.

Sewage spills onto a North Sea beach, Hartlepool, England Every day in the early 1990s, 300 million gallons of sewage entered British coastal waters, most of it untreated § §.
photo © Simon Fraser/Photo Researchers, Inc.

Distress Signals

Swim at your own risk (of disease)

Contaminated water and seafood can carry viral hepatitis, cholera, typhoid fever, and a range of stomach and intestinal diseases §. In 1993, beaches were temporarily closed, or advisories against swimming were issued, over 2400 times in the U.S., usually because of high levels of bacteria §. There are no U.S. federal requirements for notifying the public when water- quality standards are violated, and some coastal states don't monitor water at beaches §. The problem is greater in other countries, however.

Surfers Against Sewage publicizes health risks from polluted water.
This is dried toilet paper on the beach in Troon, Scotland.
photo © Surfers Against Sewage

Overfeeding chokes off marine life

In many estuaries and bays, excessive amounts of nitrogen and phosphorus result in overpopulation of plants and algae. When the plants and algae die, bacterial decomposers remove oxygen from the water, killing fish and other marine life. Sewage is a major cause of excess nitrogen in American estuaries §.

Fish kill caused by nutrient build-up,
Nanticoke River, Chesapeake Bay, 1992
photo © David W. Harp

Golden Gate warning sign
photo © Jeff Foott

Wildwood, NJ beach closing sign
photo © Michael Baytoff

Shellfish bed closing sign
photo © Bruce Wodder/The Image Bank

To the Rescue

Californians build wetlands to treat waste water

Arcata, California, created marshes where there was once a county dump and got fringe benefits. The marshes filter partially treated sewage; the water that flows through them into Humboldt Bay is cleaner than bay water. The marshes also support other wetlands and oyster beds in the bay, and provide habitats for thousands of animals. § §

Marshes, the final filters in waste-water treatment
Arcata, California
photo © Ted Streshinsky

The Clean Water Act kicks in

The Clean Water Act (CWA) was enacted in 1972 to make America's water safe for fishing and swimming. CWA programs have provided billions of dollars of federal aid to build or upgrade municipal sewage treatment facilities §, other nonpoint source pollution controls, and national estuary programs. The act also limits toxic industrial discharges into public sewers, streams, and coasts. §§

Blue Plains Sewage Treatment Plant
Washington, D.C.
photo © Hedrich-Blessing

The Clean Water Act provided the regulatory tools and financing to build this state-of-the-art plant that treats more than 300 million gallons of sewage per day. Along with a ban on phosphate detergents, the plant has helped to drastically cut the level of phosphorus entering the Potomac River and Chesapeake Bay. §

Other Resources:

Water Quality Curricula from the Cooperative Extension Service.

Ocean Planet Exhibition Floorplan

gene carl feldman ( (301) 286-9428
Judith Gradwohl, Smithsonian Institution (Curator/Ocean Planet)