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.

Metals and slowly degrading chemicals threaten inland and coastal waters. Toxic materials settle into sea-floor sediments where they accumulate as hazards to organisms that live in and feed on bottom muds. Eventually, long-lasting chemicals may enter the food web and contaminate the fish and shellfish we eat.

NOAA scientists study reproductive problems in fish from contaminated water in Puget Sound, 1989 Toxic materials don't always kill wildlife but they can still cause severe damage.
photo © Joni Packard, National Marine Fisheries Service, NOAA

Click on these boxes to identify the sources and effects of toxic materials that turn up in polluted coastal waters

Factory waste pipe, Widnes, Cheshire, England, 1991
Industrial, agricultural, household cleaning, gardening, and automotive products regularly end up in water. About 65,000 chemicals are used commercially in the U.S. today, with about 1,000 new ones added each year. Only about 300 have been extensively tested for toxicity §.
photo © David Woodfall/Tony Stone Images

Digging out waterways dredges up toxic materials

Because rivers wash silt downstream, and harbors and waterways are not naturally deep enough for modern ships, we dredge them to make them navigable. Less than 5 percent of the dredged material contains unacceptable levels of contaminants §, but disposing of it safely is a serious problem.

Each year in the United States, we remove 400 million cubic yards of sediment from channels and harbors--the equivalent of a four- lane highway, 20 feet (6 m) deep from New York to Los Angeles. §
Illustration © Bonnie Branner

New York's harbor is naturally 18 feet deep, but most ships need at least 45 feet to clear. § Many European superships require a draft of 65 feet. Ship size continues to increase, so dredging is a continuing and growing necessity.

Illustration © Bonnie Branner


Puget Sound cleans up its act

Factories, military bases, ships, sewage-treatment plants, and about 3 million residents contribute to toxic wastes in the urban bays of Puget Sound, Washington. Since 1985, the Puget Sound Water Quality Authority, a state agency, has been overseeing efforts to clean up contaminated sediments and to control the sources of pollution. §

Analyzing sediment samples to classify level of contamination, Puget Sound, 1990
State sediment-management standards and federal law regulate methods for dredging, disposing, and cleanup of contaminated sediments. §
photo © Puget Sound Water Quality Authority

Oysters rebound after TBT ban §

TBT, or tributyl tin, is added to boat paints to kill or repel barnacles and other nuisance organisms that foul ships' hulls. TBT, which seeps out of the paint into the water, keeps barnacles off, but it also affects other wildlife. In 1982, the French banned the use of TBT on most boats. Similar regulations have been adopted in the United Kingdom and the U.S.

In the late 1970s, oyster populations were declining in France and the United Kingdom. Almost all the surviving animals did not reproduce and had malformed shells. After regulations reduced the use of TBT, oyster production increased and shell deformation decreased dramatically.

A) Normal oyster, about 8 years old B) Oyster with first 5 years of growth affected by TBT, followed by 3 years after TBT ban; C) Oyster, exposed to high levels of TBT throughout 8 years of life
courtesy of Robert J. Huggett

Other Resources:

Ocean Planet Exhibition Floorplan

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