In its five-year review of the Hudson River PCB dredging project, EPA should consider the following three emerging developments in deciding whether Phase 2 can be resumed and implemented safely:
--1. High-flow events are predicted to occur with increasing frequency in future years, as illustrated last year by events such as Tropical Storms Irene and Lee; such events will drive PCB sediments mobilized by dredging downstream for decades to come;
-–2. The US Commerce Department this year added sturgeon to the Endangered Species List, requiring protection of their Lower Hudson River habitat from PCBs because, according to EPA (and others), their early life stages are unusually susceptible to PCBs, and
-–3. Scientific articles now link PCBs to developmental processes that are thought to underlie causation of autism, most notably calcium channel effects that alter nerve cell dendrite branching patterns and, in turn, alter synapse formation in developing brains (in animal bioassays).
EPA has used reported adverse effects of PCBs as justification for removing PCB-contaminated sediments via dredging, but this is misleading for three reasons. First, fundamental to EPA’s dredging plan is allowance of an increase in PCB mobilization for seven or so years of dredging on the hope that reduction will be on the horizon. However, the horizon, as always, keeps receding as it is approached. Second, natural attenuation is occurring and will continue to occur even without dredging. Third, cleaner methods of dredging can be used in place of clamshell dredging.
EPA, therefore, must decide whether and how it can justify increased exposure to PCBs associated specifically with clamshell dredging for most of the next decade, and I would say well beyond. EPA further must explicitly address the newly recognized and increased risks to human and environmental health, which already have materialized, and which will get worse before they get better as long as clamshell dredging continues for removal of PCB sediments in the Upper Hudson River.