This page is available in multiple languages:Contaminated Sediments (English)堆積物汚染 (日本語)
Much of the following information was taken from a fact sheet on contaminated sediments prepared by Coast Alliance. Visit the Clean Ocean Action website for more detailed information on the problem of contaminated sediments.
What Are Contaminated Sediments?
Pollutants from industry, agriculture and urban runoff make their way through water to the sediments (matter that settles to the bottom of a liquid) in our rivers, lakes, and the ocean. Sediments contaminated with PCBs, dioxin, pesticides, heavy metals, hydrocarbons and other pollutants have been found in every coastal region of the United States. In a 1998 inventory, the Environmental Protection Agency (EPA) identified hundreds of problem sites around the country, many of them located in coastal areas. In fact, every major harbor in the nation suffers from moderate to severe sediment contamination, according to the EPA.
People, Fish and Wildlife at Risk
Human Health Impacts:
The contaminants found in sediments have already led to human health problems. Pollutants from poisoned sediments make their way into the food chain, accumulating in fish, ducks and other wildlife. Eventually these toxic chemicals wind up on our dinner plates.
- Women who ate fish contaminated with PCBs from sediments in Lake Michigan gave birth to children with smaller heads, lower birth weights, weaker reflexes, and slower movements.
- People who ate fish from parts of the Fox River in Wisconsin were estimated to have increased cancer risks due to high levels of PCBs in the fish.
- Dioxin, pesticides and other chemicals disrupt human reproductive functions by mimicking the effects of estrogen. Declines in sperm counts, increased prostate cancer and smaller sexual organs are some of the associated health effects that can be triggered from eating fish and wildlife polluted by toxics.
Many fish populations are healthy and safe to eat, but Native Americans, low-income fishers and others who unknowingly eat fish (especially bottom-dwelling fish) from waters with polluted sediments are at risk.
- Tumors and "fin rot" have been documented in bottom-feeding fish in Puget Sound, Washington and the New York Bight.
- Genetic mutations caused by exposure to polluted sediments prompted a fish ban in parts of southern California.
- Two recent United States Geological Survey studies link toxic sediments and contaminants found in fish with hormonal imbalances in the fish.
Pollution of our waters and the sediments beneath them also harms wildlife. Scientists in the Great Lakes have studied the impact of contaminated sediments on wildlife and their discoveries are disturbing. The following deformities have been found in the Great Lakes region:
- Partially formed eyes and brains and missing body parts in young birds; adult birds with open stomachs, club feet, stunted growth and crossed bills.
- Turtles without tails.
- Male birds born with female characteristics.
Poisoned Sediments Threaten our Economy
Every year the U.S. Army Corps of Engineers dredges about 400 million tons of sediments from our nation's rivers, harbors and estuaries, enough to cover a four-lane highway stretching from New York City to Los Angeles with 20 feet of mud. Not all dredged sediments are contaminated, but testing is revealing significant contamination in many ports and harbors, which need to be dredged to accommodate ship traffic. But dredging sediments that are contaminated can re-suspend pollutants in the water, further threatening the seafood and tourism industries that depend on healthy fish and clean water. Once mud is dredged, it must be disposed. Contaminated sediments should not be dumped in coastal waters or the Great Lakes. The difficulties of safely managing contaminated sediments makes it unwise to dredge in some areas.
What Can Be Done?
- EPA should develop sediment quality criteria and standards.
- The EPA should establish guidelines for sediment contamination that protect sensitive species at sensitive life stages.
- The need to dredge should be weighed against potential economic costs to the seafood and tourism industries caused by increased pollution released by dredging and disposal. In addition, environmental impacts and threats to human health from disposal options should be considered.
- Dredging and disposal permits should be linked to strategies for pollution control and prevention.
- EPA should not revise ocean dumping regulations to allow untested sediment to be dumped in the ocean or other open waters, or to otherwise weaken the regulations.
- Efforts to weaken the Clean Water Act and other laws that control or prevent contaminated sediments should be opposed.
- States should be encouraged to ban open-water dumping of contaminated sediments in their coastal waters. As of September 1, 1997, New Jersey became the first state to ban the disposal of contaminated sediments in its ocean waters. Other states should follow New Jersey's example.
A great resource for information on contaminated sediments is on the website of Clean Ocean Action in New Jersey.
Also see EPA's Contaminated Sediment in Water website
This article is part of a series on Clean Water which looks at various threats to the water quality of our oceans, and the negative impacts polluted waters can have on the environment and human health.
For information about laws, policies, programs and conditions impacting water quality in a specific state, please visit Surfrider's State of the Beach report to find the State Report for that state, and click on the "Water Quality" indicator link.