Recent work suggests that PCB pollution may be a factor in the decline.

Hundreds of millions of dollars have since been spent in South West Michigan cleaning up the last Allied Paper mill site and the PCB pollution caused by this company.

The site was put on the Superfund list in 1987 for PAH, heavy metals and PCB pollution.

PCB pollution, associated with Westinghouse's operations, long was a concern in the area.

Because of their short time in the river, they pick up little of the PCB pollution.

Also, the state has estimated that the cost for cleaning up pockets of underground PCB pollution there could run as high as $15 million.

Other work, for example on PCB pollution and hormone disrupting substances, has been done together with consumer and environmental organizations in Korea, China, Malaysia, and other Asian countries.

There have been many programs of remediation work to reduce the PCB pollution.

In 1991, further PCB pollution was found at Bakers Falls, near the former GE Hudson Falls factory, and a program of remediation was started.

One thus has the rather bizarre situation in which PCB pollution of the Hudson has afforded the fish a greater degree of protection than they would have otherwise been given.