Sunday, May 31, 2009

FIRESIDE CHAT: Hudson River PCB Dredging

Dredging PCBs from selected Hudson River sediment ‘hotspots’, the largest PCB dredging project yet undertaken, began recently at Fort Edward, New York. Its beginning has evoked various reactions, ranging from celebration about the prospect of an eventually clean Hudson River, to concern about project impacts of noise, health effects, and diminished recreational river use and quality of use. Though I celebrate the prospect of a clean Hudson River environment, dredging won’t produce it in my lifetime.

Dredging during more than a decade of project implementation instead will produce predominantly negative effects, including degradation of water quality, increased PCB residues in Hudson River biota, and possibly serious health effects in people living in Hudson River communities. Indeed, it already has restricted recreational use of the river, as river events have been canceled and river users advised to wash their bodies thoroughly after swimming. To illustrate with a personal example: I was invited to kayak at Spiers Falls in the Hudson and, before responding, checked to see if it was upstream or downstream of the dredging project.

Washing is inefficient at removing PCBs from skin, because dermal lipid (fat) binds PCBs tightly. The advice to wash off PCBs reminds me of Lady Macbeth’s efforts to wipe her hands of King Duncan’s blood: “Out, damned spot! out, I say!” Such advice seems dramatically emblematic of ineffective concern among health officials about river users contacting PCB.

Lawsuits demanding provision of alternative drinking water supplies have resulted in expensive concessions to river towns seeking to protect their residents against PCB’s health effects, most notably the high probability that ingested PCBs can cause human cancer. This concern is valid. Switching to an alternative drinking water supply when PCBs are detected at or above a trigger concentration might solve it, but only if sampling is extensive and results provided quickly. Switching to an alternative drinking water supply, however, cannot address the many short-term health effects exerted PCBs, for example, causation of birth defects in newborn babies whose mothers were exposed to PCBs during pregnancy.

The General Electric Company (GE) is paying big bucks for dredging, but ‘we the people’ eventually may pay more. If dredging had not been required by the U. S. Environmental Protection Agency (EPA), lawsuits claiming adverse health effects would have been (indeed, have been) directed at GE as the main polluter and main defendant. In the future, however, the preponderance of human exposure to PCBs buried under river sediments will be mediated by dredging, without which the PCBs would have remained buried and isolated from ecosystems leading to such exposure. EPA will join GE as eventual defendants in any lawsuits linking dredging with PCB-associated health impacts. So, EPA’s assessment of health risks potential posed by Hudson River PCBs had better be reliable… but it is not.

Instead, EPA’s baseline health risk assessment of PCB-mediated risks in the Hudson River was found to be biased consistently in the dredging-friendly direction with respect to nine out of nine parameters determining the degree of health risk. Effectively, risks that EPA deemed low enough to justify dredging effectively were in fact never accurately quantified. The dredging project therefore represents an experiment on humans who did not consent to participate. If health risks materialize as health effects, we the people will pay. If health effects emerge that are serious and widespread in Hudson River communities, we the people will pay a lot.

Copyright © 2009 by The Center for Health Risk Assessment and Management, a Division of RAM TRAC Corporation
Posted by The Center for Health Risk Assessment and Management, a Division of RAM TRAC Corporation

Thursday, May 28, 2009


This blog will be back by June; sorry for interruption in May.