PCBs (Polychlorinated Biphenyls) in New York's Hudson River

Where Does the Buck Stop? (Part 1)

By Jennifer Manning

[Oct. 2005]


Many parties are responsible for the decades-long PCB (Polychlorinated Biphenyl) contamination of the Hudson River. Who must ultimately pay the price for cleanup? Forensic chemistry helps identify the main polluter and pollutant.

Chemical Fingerprinting: The Perp Can't Hide

The Hudson River has had a reputation for being many different things since Europeans came on the scene. The Hudson, winding through the Adirondacks and the Palisades, was often imbued with a unique pink-golden light that inspired artists such as Thomas Cole and Asher Durand, whose work became known as the Hudson River School, which is now acknowledged to be the first uniquely American art movement. Boats would take wealthy patrons up and down the river so that people could admire its beauty and setting. It was both a saltwater and freshwater fishery that supported many communities. Then the Industrial Age began to take its toll, and on historic maps of the region the Hudson River is depicted as a black line, as it was no longer considered a scenic or recreational river but, rather, a working river, an industrial passageway.

The history of the Hudson as a working river is well documented, as is the resulting pollution of the river. There are multiple contaminants in the river as a result of decades of industrial dumping in the water; however, based on studies performed by multiple government agencies (e.g., the US Environmental Protection Agency and the US Army Corps of Engineers) and private contractors, polycyclic chlorinated biphenyls, or PCBs, are the primary chemicals of concern (COC).

These days the Hudson River is still a legend, but not for its beauty or its usefulness to industry. Today it is known, first of all, for being so devastatingly contaminated, and second, for being the subject of one of the largest, most innovative - and most expensive - environmental remediation projects in US history.

A Monster of our Own Creation

Once the primary COC was identified and the government determined that the river must be cleaned up to preserve the health and safety of humans and the environment, the next step was deciding who was responsible for dumping the PCBs into the Hudson River in the first place. Given the multiple polluters, the many decades of dumping, and the complexity of the Hudson River itself, this was not an easy task. However, PCBs have something that many other contaminants, such as lead, chlordane, dieldrin, and heptachlor epoxide, do not: while those chemicals can occur in nature, PCBs are unnatural, and they are ours.

PCBs are synthetic mixtures of up to 209 different compounds (referred to as congeners) that include a biphenyl and up to ten chlorine atoms (Agency for Toxic Substances and Disease Registry [ATSDR], 2000). As indicated by the ATSDR, "some commercial PCB mixtures are known in the United States by their industrial trade name, Aroclor. For example, the name Aroclor 1254 means that the mixture contains approximately 54% chlorine by weight, as indicated by the second two digits in the name" (ATSDR, 2000). Similar mixtures were produced and sold elsewhere under different trade names. PCBs are also part of a group of contaminants known as dense non-aqueous-phase liquids, or DNAPLs, that are particularly persistent in the environment. This persistence means that they are even more difficult to remediate than many other contaminants, as DNAPLs can enter and affect many aspects of the environment and food chain.

Because PCBs are manmade and are often the unique byproduct of specific products or processes, it is possible to trace the signal, or fingerprint, of an Aroclor to the corporation that manufactured it. There are times when multiple corporations produced the same Aroclor, but frequently a manufacturing process will be used by a single company, thus producing a distinctive contaminant. Similarly, a combination of Aroclors will frequently be the byproduct of one corporation's manufacturing process, so identifying that particular PCB mixture can point to the perpetrator of the contamination.

The Magic Number

PCBs were introduced throughout New York State through the recycling of carbonless copy paper that contained Aroclor 1242. According to USEPA, "the total discharge of PCBs from all recycle mills in New York State was estimated at 2.3 kg/year (5 lb/year) to the Hudson River from Bakers Falls to Troy (NYSDEC, 1978). This is, however, an insignificant amount compared to GE's estimated 14 kg/day (30 lb/day) or 5,000 kg/year (11,000 lb/year) discharges at Fort Edward and Hudson Falls [which are in what is now the upper portion of the Superfund site] during the early 1970s (Tofflemire and Quinn, 1979)" (TAMS et al., 1997).

With respect to the Hudson River, it was well known that the General Electric Corporation contributed most of the PCBs to the river, primarily through use of PCBs for capacitor manufacturing at Hudson Falls from 1952 to 1977. Reported uses consisted mainly of Aroclor 1254 (1952 to 1955), Aroclor 1242 (1955 to 1971), and Aroclor 1016 (1971 to 1977) (TAMS et al., 1991).

While all Aroclor congeners are harmful, some are more toxic than others. For example, Aroclor 1242 is ranked as more hazardous than most chemicals by a variety of agencies (Environmental Defense, 2005). In fact, the extreme harm caused by PCBs directly led to the government implementing the Toxic Substances Control Act (TSCA) in 1976.

Pointing the Finger

Many people, particularly residents of the communities along the river, believe that the river is cleaning itself up. They cite trends of reduced levels of PCBs in the lower river and increased clarity of water. However, PCBs are invisible, odorless, persistent in the environment, and are absorbed into the river sediment. Thus, the damage they do is hidden and insidious, as they bioaccumulate up through the food chain from plants growing in the sediment to the microorganisms feeding on those plants to the fish feeding on the organisms and ultimately to the animals and people that feed on the fish.

When this contaminated sediment is disturbed, the PCBs are re-released into the water column. Thus, PCBs are not being safely "buried" in the sediment, with this burial leading to cleaner water, and the river is not cleaning itself up, despite people's hopes. Something as simple as a dry year when the river has low flow will release PCBs back into the river water. In general, levels of PCBs continue to fluctuate, and breaches of some of GE's holding dams bled huge amounts of the contaminant into the river.

Given so many PCB congeners and so many polluters, how was it determined that GE was the potentially responsible party, or PRP? (A PRP is an entity that is determined, through a variety of methods such as forensic chemistry, to be primarily responsible for the contamination of a site and thus primarily responsible for remediation of that site.)



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