Dredging the Hudson River

For the past year, the subject of polychlorinated biphenyls in the Hudson River and what should be done about them has been discussed by politicians and residents all over the capital region. Often the top story on the local news, the front page headline of the newspaper, the subject of a special on television, or the reason for a town meeting, dredging has become a much debated topic. With all the information being exchanged and opinions published, it is easy for the average person to become confused. In an attempt to make things clear, the following report defines dredging, PCBs, and presents a short discussion of each side of the Hudson River dredging debate.


Webster’s Dictionary defines polychlorinated biphenyls (PCBs) as any of several compounds that are produced by replacing hydrogen atoms in biphenyl with chlorine, having various industrial applications and are poisonous environmental pollutants that tend to accumulate in animal tissue. They have a high resistance to excessive temperatures and do not disingrate in water. Because of these qualities, they can be useful in paints, lubricants, and most commonly, as a dielectric in capacitors.

Unfortunately, PCBs are hazardous to human and animal health, as well as to the environment. In studies published by the Agency for Toxic Substances and Disease Registry (ATSDR), the following health concerns are related to the ingestion of PCB’s in people:

Reproductive functions may be disrupted by exposure to PCBs.
Neurobehavioral and developmental deficits occur in newborns and through school-aged children who had in utero exposure to PCBs.
Liver disease and diabetes, and effects on the thyroid and immune systems are associated with elevated serum levels of PCBs.
Increased cancer risks, such as non-Hodgkin’s lymphoma, are associated with PCB exposures.

Many companies produced PCBs in the 1930’s and 1940’s and because the chemical does not decompose, PCBs are still present in soil and rivers, subsequently ending up in fish and other wildlife. According to the Environmental Protection Agency (EPA), PCBs build up in the environment, and larger concentrations are found higher in the food chain. Eating contaminated fish is the most likely way for PCBs to get into the human body. In 1997, the EPA banned the production of PCB’s and they were classified as a probable human carcinogen.


Dredging is the removal of soil or material from the bottom of a river, lake or ocean harbor. (Encarta Online 8 Apr 2001). There are two distinctive types of dredging; navigation and construction dredging, and environmental dredging. Navigation and construction dredging are used to remove sediment that has accumulated to a level where the water depth is insufficient to support safe navigation (Huskie 2). Navigation dredging tends to use large open clamshell dredges. Environmental dredging utilizes hydraulic dredges that act as a vacuum to remove contaminated sediments such as PCBs, (“Environmental” Clearwater.org). A representation of these dredges is on the following page courtesy of Keene Engineering (“Environmental” Clearwater.org). A sediment that is toxic or hazardous, once removed, must be placed in an approved hazardous waste landfill or, treated until it is harmless (Huskie 2).


The following is a version of a timeline published by Clearwater Hudson River Sloop, an organization of volunteers dedicated to preserving the Hudson River. It describes General Electric’s (GE) relationship with PCB’s and the river. It is believed that GE legally dumped over one million pounds of PCBs into the Hudson.

1936: First study revealing major health and safety problems associated with PCBs.
1947: General Electric (GE) starts using PCBs in the manufacture of electrical capacitors at its Ft. Edward plant on the eastern shore of the Hudson River.
1973: Ft. Edward Dam removed from upper Hudson River, causing large amounts of PCBs to flow into the lower Hudson.
1974: An EPA study shows high levels of PCBs in Hudson River fish.
1976: Congress passes the Toxic Substance Control Act banning the manufacture of PCBs and prohibiting all uses except in totally enclosed systems.
2/76: Department for Environmental Conservation (DEC) makes it illegal to fish in the upper Hudson from the FT. Edward Dam to the federal dam at Albany, closes Hudson River commercial fisheries, and warns people about the dangers of eating Hudson River fish.
2/76: Administrative hearing finds that the PCB pollution was GE’s fault.
4/76: The worst flood in 100 years causes large amounts of polluted sediments