Contaminated Sediments Program

Monitoring Links

Mudpuppy at Work - Great Lakes Sediment Program

Sediment Remediation

Barge at Manistique River

The remediation of the Manistique River and Harbor is currently underway. Since 1996, approximately 90,000 yds³ of PCB-contaminated sediment have been removed, primarily with the use of a hydraulic cutterhead dredge. This remediation is expected to be completed in 1999, when the estimated 30,000 yds³ of contaminated sediment which remain are scheduled to be dredged.


Ottawa River, Ohio	OMC site near Waukegan, IL

Studies conducted between 1988 and 1994 indicated elevated levels of PCBs in a tributary to the Ottawa River, part of the Maumee River Area of Concern. Under a voluntary partnership among GenCorp, Ohio EPA, the City of Toledo and U.S. EPA's GLNPO, 10,000 yds³ (56,000 pounds) of PCB-contaminated sediment were removed from this tributary in 1998.

The remediation of the Outboard Marine Corporation Site in the Waukegan Harbor Area of Concern took place between 1989 and 1992. Approximately 50,000 yds³ of PCB-contaminated sediment were removed from the Harbor. Highly contaminated sediment (>500 ppm PCB) was treated by a low temperature thermal extraction procedure, which removed 97% of PCBs by mass and separated PCB oils from sediments. Sediments with PCB concentrations between 50 and 500 ppm were placed in containment cells which had been constructed on the Waukegan Harbor site.

Research Vessel Mudpuppy

The Reasearch Vessel Mudpuppy (R/V Mudpuppy) is a 32-foot flat-bottom boat operated by U.S. EPA's GLNPO, specifically designed for determining the nature and extent of sediment contamination in the Great Lakes Basin.
As of 1998, the R/V Mudpuppy has conducted surveys at 26 locations, including 21 of the 31 U.S. Great Lakes Areas of Concern.
The R/V Mudpuppy uses a vibro-coring unit to take sediment samples up to 15 feet in depth from locations with water depths between 2 and 50 feet.	Once samples are collected, they can be processed on the boat or at a land based facility.

Contaminated Sediments - The Problem

map of Mudpuppy assessment sites Harmful pollutants enter the Great Lakes from many sources. Eventually, many of them sink to the bottom where they adhere to sediments.

Sediments are not only a sink for pollutants, though, they are also a source.

The pollutants may be stirred up by wind, water, currents, ships or bottom dwelling organisms.

Contaminants find their way into the lakes' food chain, either directly, as they are absorbed by the bottom dwelling organisms, or from the water column, after they are stirred up. Fish, fish-eating birds, other animals and people may be affected.

Some of the largest concentrations of toxic pollutants in the Great Lakes are located in 43 sites referred to as Areas of Concern.