What are PCBs, and how do they harm the environment?

What are PCBs, and how do they harm the environment?

—Dale Roach, Waterford, MI

Polychlorinated biphenyls (PCBs) are various man-made mixtures of chlorinated compounds that were first made by the Swann Chemical Company back in 1880. PCBs were once considered a “miracle product” for manufacturers because of their water insolubility, high tolerance for heat, and chemical stability. This led to their widespread use in the making of products such as inks, dyes, paints, adhesives, carbonless papers, lubricants, flame-retardants, surface coatings and sealants, and industrial fluids.

As early as 1936, the harmful effects and health risks of PCBs were known, and today they are well documented. PCBs cause cancer in studies using animals, and are therefore classified by the U.S. Environmental Protection Agency (EPA) as probable human carcinogens. PCBs also cause liver, kidney and nervous system disorders, as well as developmental and reproductive abnormalities.

Most insidious is that PCBs increase in concentration as much as 1,000-fold as they move up the food chain. This “bioaccumulation” is of special concern in areas where wildlife and humans consume PCB-contaminated fish. Because of such harmful effects, the EPA banned PCBs in 1977, but PCB problems are far from over.

In one highly publicized case, two General Electric (GE) plants in upstate New York dumped 1.3 million pounds of PCBs into New York’s Hudson River between 1947 and 1977. Although the dumping ceased more than 25 years ago and concentrations have declined since, they have stabilized at levels that are significantly higher than those considered safe for human consumption of fish. According to Riverkeeper, a New York-based environmental organization, large quantities of PCBs remain concentrated in sediment in northern portions of the Hudson, and are found in fish and wildlife throughout the river’s ecosystem.

Forty so-called PCB “hot spots” have been identified in a six-mile stretch directly downstream from the two GE plants, and in February 2002 the EPA decided to proceed with a comprehensive cleanup of the Hudson River. The plan calls for removing 100,000 pounds of PCB contaminated sediments from the Upper Hudson River by dredging, a plan that will cost GE $460 million. GE has contested the ruling, arguing that its efforts should be limited to conducting the design of the cleanup, estimated at approximately $30 million, and preventing additional PCB contamination.

PCBs from GE have also contaminated the Housatonic River in Massachusetts and Connecticut, leading to its listing by the group American Rivers as one of “America’s Most Endangered Rivers of 2004.”

CONTACTS: Environmental Protection Agency, (202) 260-1876, www.epa.gov/pbt/pcbs.htm; Hudson Riverkeeper, (800) 21-RIVER, www.riverkeeper.org; General Electric, (203) 373-3476, www.ge.com; American Rivers, (202) 347-7550, www.amrivers.org.