Hudson River Dredging: Westchester & New York City, Next Stops for Mobilized PCB

Fred LeBrun’s April-24th Commentary in the Albany Times Union Newspaper, titled Dredging up a PCB Resolution, describes Hudson River PCB dredging as simply removing two million cubic yards of tainted sediments. He visualizes an armada of 100 vessels excavating noxious PCB, and loading it into railcars for landfilling far away. Mr. LeBrun’s columns on birds and bees reveal a great naturalist, but PCB dredging requires different expertise, and his explication is technically flawed.

Mr. LeBrun fails to appreciate that PCB preferentially binds to the finest particles such as silt and mud, whereas dredging preferentially removes coarser objects such as sand grains, rocks, tree stumps, and construction debris. In 2009, dredging Phase 1 near Fort Edward, New York revealed surface PCB sheens, indicating the presence of liquid PCB beneath the surface, which clamshell dredges cannot capture. PCB that is bound to fine silts and muds can flow many miles before settling. The finest particles and oily liquid PCB never settle; they travel downstream, entering ecosystems and air. If unchecked, they soon will invade Westchester County and New York City. They will not flow out to sea, because the lower Hudson is an estuarine system, subject to the ebb and flow of tides; materials carried by rivers downstream to estuarine systems tend to accumulate rather than flow unimpeded to the ocean.

Mr. LeBrun must have noticed, as we did, that clamshell dredges used in Phase 1 leaked much if not most of the fine silt and mud back into the river. He should have concluded, as GE reported in 2010, that dredging had mobilized PCB-contaminated sediments, spreading it widely on previously uncontaminated sections of the river bottom. In short, Mr. LeBrun’s misconception is that the mass and volume of buried PCB is the main problem, whereas the area of river bottom from which PCB sediments can be scoured by currents is actually the main problem… and that area is increasing dramatically, probably by a factor of over a thousand-fold already. Before dredging, nearly all of the buried PCB sediment was immobile, but dredging now has mobilized much of it. As a naturalist, Mr. LeBrun will rue the already-occurring effects on Hudson River ecosystems, such as a five-fold increase in PCB concentrations found in fish tissue.

Mr. LeBrun’s armada is moving downstream for dredging Phase 2 to commence this month. Phase 3 of Hudson River PCB remediation has yet to be announced. It will not involve Fort Edward, and it will not involve clamshell dredging. It will involve Westchester County and New York City, neither of which would permit clamshell dredging anywhere nearby. Influential columnists like Mr. LeBrun should seek to protect our communities and ecosystems, just as those to our south surely will protect theirs.