Summary of GE's Evaluation of the First Phase of the Hudson River Dredging Project

SARATOGA SPRINGS, NY (02/23/2010)(readMedia)-- GE conducted the first phase of the Upper Hudson River Dredging Project between May 15 and December 4, 2009. Dredging was conducted 24 hours a day, six days a week and was overseen by the U.S. Environmental Protection Agency, New York State and the U.S. Army Corps of Engineers.

The agreement between EPA and GE under which the project is being conducted required that the results of Phase 1 be evaluated by an independent peer review panel. Both EPA and GE prepared evaluations of the project for submission to the peer review. GE's evaluation is based on its analysis of more than 18,000 air, water and sediment samples that were collected during and after dredging. In its report and presentation to the peer reviewers, GE's goal is to improve the second phase of the dredging project so that it achieves the environmental goals EPA has forecast.

In 2004, EPA established engineering performance standards to govern the project. It required that dredging meet these standards consistently and simultaneously. Despite the use of the best available dredging technology, daily oversight by regulatory agencies, and multiple modifications in the dredging process, the standards could not be met consistently and simultaneously because they are in conflict with one another. For example, attempts to achieve the Productivity Standard led to exceedances in the Resuspension Standard. Attempts to limit resuspension or to meet the Residual Standard inhibited productivity.

The first phase of dredging released more PCBs to the water, air and fish in the Upper Hudson and more PCBs to the Lower Hudson than EPA predicted. GE believes that practical adjustments to the standards should be made to help ensure the rest of the project meets EPA's goals to reduce PCB levels in fish, water and sediments, to reduce PCB transport downstream and to reduce PCB levels in surface sediments where they are bioavailable to fish and wildlife.

The Resuspension Standard

• EPA established two resuspension standards to ensure that dredging did not cause exceedances of the drinking water standard and did not release more PCBs into the river than would have happened over time without dredging.

• The first standard requires that during dredging the concentration of PCBs in the water not exceed the federal drinking water standard of 500 parts per trillion. (The PCB level in the water before dredging averaged 30 to 50 parts per trillion.) The second standard requires that the total mass of PCBs resuspended during dredging, as measured at Waterford, not exceed 117 kilograms (258 pounds).

• Because of the volume of PCBs being dredged and the velocity of the river, and despite the fact that more than 55 percent of the volume of sediment dredged was subject to flow control/ diversion during dredging, both standards were exceeded during Phase 1.

• The federal drinking water standard was exceeded 10 times.
• Dredging released 200 kg (440 pounds) of PCBs, as measured at Waterford, 30 miles downstream, in exceedance of EPA's maximum allowable limit.

• EPA had forecast that dredging would resuspend 0.13 percent of the PCBs dredged. In fact, dredging released approximately 25 times more than that - 3 percent to 4 percent of the PCBs dredged, consistent with the level of resuspension seen at other dredging projects, such as the Grasse and Fox rivers.

• Resuspension also had another unforeseen impact not accounted for in EPA's performance standards. It released PCBs to surface sediments downstream. This resulted in higher post-dredging levels of PCBs in surface sediments that are bioavailable to fish.

• The level of resuspension led to significant increases 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.

• The resuspension problem was not eliminated by resuspension controls, such as a bank-to- bank flow control structure installed at the head of the eastern channel of Rogers Island where substantial dredging took place and a sheet-piled enclosure near Griffin Island. In fact, the higher-than-predicted resuspension occurred even with more than 55 percent of the volume of sediment dredged subject to flow control. Sheet piling reduced but did not stop PCBs from moving into the river and created a pool of water with elevated levels of PCBs, leading to elevated PCB levels in air nearby that often exceeded EPA's performance standard for air quality.

• Despite the Phase 1 experience, EPA is considering requiring significantly more sediment removal in Phase 2 - requiring a rate of removal double what was achieved on the best days of Phase 1. This would lead to the release of 2,000 kg (4,400 pounds) of PCBs downstream over the life of the dredging project. This also would mean that the drinking water standard of 500 parts per trillion would be routinely exceeded during Phase 2. This directly contradicts EPA's own goals for the remedy and eliminates the benefits of dredging forecast by EPA.

• A GE analysis shows that even the original standard set by EPA for downstream transport of PCBs (650 kg) is too high to achieve the environmental benefits EPA forecast and that it may be the result of an error by EPA. To ensure that dredging releases no more PCBs than would have been released without dredging, a lower maximum limit on PCBs released downstream should be set.

• To better control resuspension during Phase 2, EPA has recommended silt curtains with an adsorbent material and anchors. Silt curtains with an adsorbent material are being tested now; they have not been used on a full-scale project. The silt curtains used during the first phase of dredging were within two feet of the river bottom and anchored in a manner EPA approved. Dredging experience on the Grasse River and elsewhere shows that additional anchoring causes the silt curtains to tear when river flows and velocity rise, causing more resuspension and likely delays in the project.

• GE has evaluated other ways to reduce resuspension, including dredging more slowly and avoiding dredging under high velocity conditions. Dredging more slowly does not reduce the mass of PCBs released downstream but it does increase the length of time needed to dredge and the duration of elevated levels of PCBs in fish. Avoiding dredging at times of high flow is not practical in the main channel of the Upper Hudson where much of the dredging will take place and will delay the project. The use of flow controls did not eliminate resuspension during Phase 1 and is not likely to do so in Phase 2. Moreover, many Phase 2 dredging areas are not suitable for structural controls.

• To achieve EPA's forecast of reduced PCB levels in water, sediment and fish, GE recommends setting a not-to-exceed maximum limit on the mass of PCBs the dredging releases downstream. GE also recommends keeping the federal drinking water standard as a performance standard and maintaining EPA's five-year schedule for the second phase of the project.

The Productivity Standard

• For the first phase of dredging, EPA established a target for removal of 265,000 cubic yards of sediment. In fact, 286,000 cubic yards of sediment containing 16,300 kg (35,000 pounds) of PCBs was removed. Dredging took place 24 hours a day, six days a week. At times, more than 100 vessels were at work on the river. More than 500 people were employed.

• Dredging was conducted in only 10 of 18 areas targeted for dredging. Dredging could not be conducted in all of the areas originally targeted because EPA required removal of more than 120,000 additional cubic yards of sediment than forecast in the 10 areas.

• EPA established the Productivity Standard in 2004 to ensure that the dredging project was completed in six years – one year for Phase 1, and five years for Phase 2. A longer dredging project would extend resuspension of PCBs in water and result in elevated PCB levels in fish for a longer period of time.

• The Productivity Standard required removal of 89,000 cubic yards of sediment in a single month during Phase 1. The standard was not met. In the best month for productivity in Phase 1, 77,300 cubic yards of sediment was removed.

• Productivity was hampered by three factors: resuspension of PCBs, which resulted in dredging slowdowns and adjustments; exceedances in the air quality standard, which also required dredging process modifications; and the multiple, unproductive re-dredging attempts necessary to meet the Residual Standard (discussed on the following page).

• For Phase 2, EPA has assumed that twice as much sediment can be dredged each month than was removed during the best month in Phase 1. EPA is considering requiring removal of more than 100,000 cubic yards per month. GE's analysis shows it is possible to dredge 75,000 to 100,000 cubic yards of sediment each month, but that resuspension of PCBs will prevent achieving this rate.

• EPA also has assumed dredging can begin early in the season despite high-flow events that pose resuspension and safety hazards; that there will be no shutdowns due to resuspension or weather; nor delays due to multiple re-dredging attempts to meet the Residual Standard.

• EPA's productivity requirement for Phase 2 is not practical. It ignores the experience of Phase 1 and the demonstrated result that greater removal means greater resuspension and higher PCB levels in water, air, sediment and fish.

• GE recommends that the five-year duration of Phase 2 be retained and that a practical Productivity Standard be established in accord with the other performance standards to protect the environmental benefits that EPA forecast.

The Residual Standard

• EPA established the Residual Standard - the amount of PCBs left on the surface sediments after dredging - to reduce the amount of PCBs that are or may become bioavailable. EPA's target average for five-acre dredge areas was approximately 0.25 ppm, about one-quarter of a part per million. Sampling was required after each dredging pass to measure the mass of PCBs left behind.

• The standard was not met in most areas dredged. In all but one area, despite multiple re-dredging attempts, the standard was met only with capping, i.e. putting down a clean layer of soil over parts of the area.

• In addition, the testing, sampling and assessment of each of the dredging areas required more time than expected. Dredging was completed in 73 days. But, testing, sampling and assessment required an additional 35 days. This meant that each of the areas of the river that were dredged were open for at least three months. This hampered efforts to achieve the Productivity Standard.

• In all but one of the five-acre areas dredged, 90 percent of the PCB mass targeted for removal was captured in the first two dredging passes. Nevertheless, achieving the Residual Standard still required further re-dredging attempts even when they removed minimal additional PCBs.

• EPA has made a recommendation to correct the problem of unproductive re-dredging, but the recommended approach makes the problem worse. EPA would require that nine inches more sediment be routinely removed in each dredging area. GE's analysis shows that this would result in removal, at a minimum, of an additional 400,000 cubic yards of clean sediment, requiring dredging at an even faster rate than achieved during Phase 1. EPA also proposes to require additional sampling and re-sampling in each dredge area, in an attempt to reduce the number of dredge passes. In reality, EPA's recommendations will result in four dredge passes in most areas, which will further reduce productivity; and will require transportation and disposal of 400,000 cubic yards of additional material.

• To remediate the majority of bioavailable PCBs in the most efficient manner while keeping dredge areas open for the least amount of time, GE recommends that the Residual Standard requirements for multiple re-dredging passes be modified as part of the Phase 2 design process after EPA establishes a not-to-exceed maximum limit for the mass of PCBs that dredging can release downstream.

Conclusions

Phase 1 of the Hudson River Dredging Project was designed as a test to determine whether the engineering performance standards established by EPA could be met simultaneously and consistently. The experience showed that the standards are in conflict with each other and cannot be met.

GE recommends that practical adjustments be made in the standards to help ensure the project achieves the environmental benefits EPA forecast. The goals of the dredging project, as established by EPA, are to reduce PCB levels in water and fish, to reduce downstream transport of PCBs, and to reduce PCBs that are bioavailable to fish and wildlife.

The Phase 1 data and experience demonstrated that resuspension of PCBs threatens achievement of these goals. It also demonstrated that resuspension is directly linked to the mass of PCBs removed and that resuspension controls generally were not effective.

To achieve the goals EPA established for this project, GE believes that EPA must impose a not-to-exceed maximum limit on the mass of PCBs that dredging releases downstream over the five years of Phase 2. To comply with the maximum limit, GE recommends that EPA modify the Resuspension and Residual standards.

To read GE's full report on the first phase of dredging, please visit http://www.hudsondredging.com