GE Completes Evaluation of Phase 1 of Dredging
In 2009, one of the largest environmental dredging projects began in the Upper Hudson River. From May through October, GE’s crews worked 24 hours a day, six days a week, to dredge river sediments to remove PCBs. As many as 100 vessels operated in the river at any one time to get the work done.
EPA conceptualized this phase of the project as a test to determine whether the strict performance standards it established to govern the project could be achieved consistently and simultaneously. To measure compliance with these standards, more than 18,000 sediment, air and water samples were collected, as well as thousands of noise, odor and lighting measurements. The Hudson project is the most closely monitored environmental dredging project in history (click here to view monitoring data).
Dredging was performed in areas around Rogers Island in Fort Edward, N.Y., and in the eastern channel of Griffin Island, located approximately three miles downstream.
Mechanical dredges with environmental clamshell buckets were used to remove river sediments. As many as 12 dredges operated simultaneously to remove nearly 290,000 cubic yards of sediment targeted by EPA for removal.
Dredged material was loaded onto 195-foot-long hopper barges that were transported by tug boats to a processing and transportation facility located on the Champlain Canal one mile upstream. The facility took nearly 18 months to construct, and included a new 1,500-foot wharf, two large buildings to remove water from dredged sediments and treat the water, temporary staging areas for processed dredged sediments and a new rail yard with seven miles of newly-installed track. A federally-permitted disposal facility was selected to accept Hudson dredged sediments via rail.
After dredging was completed in a dredge area, sampling was performed to assess whether PCB levels in the remaining sediments met EPA’s standard. Depending on these results, more dredging was performed, or clean sand and gravel or capping material was placed in the area. All told, approximately 150,000 tons of rock and dirt was used for backfilling and capping activities.
Implementation of the project was a collaborative effort between GE and the government and EPA has praised the effort. As reported by the Associated Press at the end of Phase 1, EPA’s Acting Regional Administrator George Pavlou stated, “We took on Mother Nature. She threw everything at us but the kitchen sink, from timber, to boats that were sunk, to tree branches. We prevailed in the end.”
GE provided the funding and retained expert contractors to perform the work. EPA reviewed and approved all the designs and, where it felt it appropriate, directed modifications. EPA, New York State and the U.S. Army Corps of Engineers oversaw the dredging operations 24/7.
What We’ve Learned So Far
Dredging did not, nor could it, achieve the rigorous standards EPA established for the project. Dredging released 3% to 4% of the PCBs dredged, consistent with the level of resuspension seen at other dredging projects, such as the Grasse and Fox rivers. PCB levels in water increased from 30-50 parts per trillion before dredging to 100-400 parts per trillion during dredging. These higher PCB concentrations in the water continued even when dredging stopped.
The level of resuspension led to an immediate spike in PCB levels in Upper Hudson fish. PCBs in yearling pumpkinseed and forage fish in the Thompson Island Pool increased by nearly 500 percent. At Albany and Troy, nearly 40 miles downstream of dredging activities, PCB levels in the two species rose 40 percent to 65 percent.
Dredging released significantly more PCBs to the Lower Hudson — about 440 pounds more than before dredging. This is nearly twice the limit set for the project by EPA. PCB levels in air exceeded EPA’s standard 105 times, and the federal drinking water standard of 500 parts per trillion was exceeded 10 times. EPA’s Productivity Standard — which required that 89,000 cubic yards of sediment be removed in a single month during Phase 1 — was never achieved during the six months of dredging. In the best month of productivity in Phase 1, 77,300 cubic yards of sediment was removed.
Phase 1 demonstrated that EPA’s performance standards are in conflict and should be modified. Attempts to meet the Productivity Standard resulted in higher PCB levels in the water, in conflict with the Resuspension and Air Quality standards. And even with dredging at a slower-than-required pace, the quantity of PCBs flowing into the Lower Hudson increased, in conflict with limits set for downstream PCB load.
GE recommends that practical adjustments be made to EPA’s standards to help achieve EPA’s forecast of reducing PCB levels in water, sediment and fish. These adjustments may include: setting a not-to-exceed maximum limit on the mass of PCBs that dredging releases downstream; keeping the federal drinking water standard as a performance standard; maintaining EPA’s five-year schedule for the second phase of the project; and, adjusting the Productivity and Residual standards to achieve EPA’s goals of reducing the amount of PCBs in water, sediment and transported downstream.
