At the toxic tradeshow

PITTSFIELD
A LOWLY WORM might finally be the agent that cleanses rivers and harbors of polychlorinated biphenyls, the suspected carcinogens that until the late 1970s were widely used as insulating fluids in transformers and other products. The same indestructibility that made PCBs so valuable to industry now makes them a long-lasting environmental hazard. Recently, the worm solution was among several touted at a kind of trade show for PCB removal in a city that was once a world leader in General Electric transformer production.

The Housatonic River, whose east and west branches meet here and then flow to Long Island Sound, is one of two major PCB hotspots in the state. New Bedford harbor is the other. Taking in the cleanup wares at the trade show were representatives of the federal Environmental Protection Agency, the Massachusetts and Connecticut departments of environmental protection, Pittsfield officials, Massachusetts Fish and Wildlife, Massachusetts Audubon, citizens groups, and GE.

The holy grail of PCB cleanup is a process that could break down and render harmless the chemical's tightly bonded molecule right in the river sediment or floodplain soil. This would avoid the expense and damage to the landscape that removal by dredging requires. About half of all PCBs in the 10 miles of highest contamination in Pittsfield and Lenox are in the floodplain and not the river bottom. No one wants to see the floodplain's wildlife sanctuaries chewed up with dredging.

This is where "eisenia foetida" comes in. A Slovakian company discovered that this worm produces an enzyme capable of breaking down hydrocarbons. The firm showed video of its Enzymmix being pumped into the fuel-soaked soil of European service stations.

In another approach, PCBs lose their chlorine atoms when exposed to a form of magnesium. Lacing sediment with activated carbon causes PCBs to glom onto the carbon. This keeps them from being taken up into the flesh of small animals and moving up the food chain to game birds or fish, where they present the greatest threat to humans.

Other vendors proposed a "molecular dissociation" process using a 40,000 degree Fahrenheit plasma arc and another process in which PCBs are broken down by intense vibrational sonic energy. By the end of the day, it looked to be simply a matter of choosing one of this murderers' row of high-tech (and likely costly) methods. But the University of New Hampshire's Kevin Gardner noted that, while PCBs are banned, the country continues to conduct experiments with other suspect substances, like the flame retardants showing up in the flesh of Arctic seals. Habits of human carelessness can be as persistent as the PCB molecule.

DONALD MacGILLIS