In the Baltimore, MD harbor I recall they've found bacteria in the sediment next to the power plant that actually are digesting the once thought "immutable" PCBs that scientists for GE also objecting to dredging with newer instruments, spectrometers, had then found that PCB's could have a "half life" though in hundreds of years. They however did not know what was doing it.
Bio-remediation is a big hope and I've seen it proposed for some of the projects in the EPA Superfund National Priority clean-ups worked on for archaeology resources, under the US 106 statute, 1985-1994 before liabilities became larger issues, an impasse to cleanup, until even today, reported "stimulus funds" are being used to finish cleanups.
Involved in various archaeology studies for the proposed "solutions" to Upper Hudson River PCB dredging, I am glad to see it. For twenty-five years on/off mandated archaeology studies and work which precedes designs or works with them, i.e., EPA's Marathon Battery site in Cold Spring, NY, have been done. It has also kept the Champlain Canal clogged by law, maintenance dredging not permitted.
My question becomes are ancillary features also going to be remediated? In this final proposal it stated that a small bit of PCBs will continue to flow over Federal Dam even after the cleanup and is the possible entrapment by other river features considered? The largest personal injury lawsuit in the Nation's history was filed, for $1 billion, in Fort Edward, NY or is that part of another phase?