New Bedford Harbor

New Bedford Harbor Cleanup Plans, Technical Documents and Environmental Data

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Current / Anticipated Work in 2013

Over the 2012 cleanup season, EPA successfully removed 17,275 tons (over 20,000 cubic yards) of contaminated material from about 6 acres of New Bedford Harbor. There were 52 days of active hydraulic dredging  Exit in the Upper Harbor. To date, about 230,357 cubic yards has been removed. This is roughly 25% of the total anticipated volume of contamination targeted in EPA’s 1998 Cleanup Plan which consists of the 1998 Record of Decision (ROD) and four subsequent Explanation of Significant Differences (ESDs).

CAD Cell Design

EPA anticipates completing the design of the lower harbor Confined Aquatic Disposal Cell (LHCC) by the end of 2012. The project will then be put out to bid by the City of New Bedford Harbor Development Commission (HDC). This work will consist of digging a CAD cell in the lower harbor with a capacity of about 300,000 cubic yards to hold PCB contaminated material from the lower harbor, and a small portion of the upper harbor. If all goes as planned, EPA hopes to begin dredging contaminated sediments to be placed into the newly constructed LHCC during the second half of 2013

Outer Harbor Study

The Outer Harbor (Operable Unit # 3), which consists of approximately 17,000 acres outside of and adjacent to the New Bedford Hurricane Barrier, is currently undergoing a Remedial Investigation/Feasibility (RI/FS) Study. This study includes field sampling to determine the nature and extent of contamination, conducting human health and ecological risk assessments, a review of technologies and range of response actions to address any risks that are found. Completion of the RI/FS for the outer harbor is scheduled for completion in late 2013. EPA will continue to keep the public informed about the progress of the outer harbor study at the public meetings.

How does hydraulic dredging work?

The current hydraulic, or full-scale dredging process, removes contaminated sediment from the harbor bottom by a vacuum-like system of dredges, pipelines and processing facilities. Before areas are hydraulically dredged, any large debris such as tires, mounds of bricks, etc are removed from the harbor bottom to avoid any damage to the equipment. Once the areas have been cleared, the hydraulic dredge pumps water and sediment through an underwater pipeline to EPA's de-sanding facility Exit on Sawyer Street in New Bedford. The coarse sand and shells are filtered from the sediment and silt that contain most of the PCB contamination. The filtered coarse material is temporarily stored and tested at Sawyer Street before it is sent to an off-site, licensed disposal. The remaining silt and water is pumped 1.4 miles south to EPA's de-watering facility  Exit, where large filter presses squeeze water from the silt. EPA treats the water Exit to strict water quality standards before it is released back into the harbor, while the packed sediment is safely transported to a licensed PCB landfill in Michigan.

  • Following the discovery of a shipwreck in 2009 (PDF) (13 pp, 1.5 MB), as well as an anchor of possible historic value in late 2010, archaeological surveys are conducted as necessary and an "on-call" marine archaeologist is available should additional artifacts be uncovered during the cleanup work.

During active cleanup work, EPA monitors the air and water quality  Exit to ensure that environmental quality is not impacted and that the cleanup continues to be protective for the workers and surrounding communities. Additionally, EPA is working with the adjacent cities and towns to ensure that fishing restrictions and exposure risks continue to be communicated to the public.

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Site Description and History

The 18,000-acre New Bedford site is an urban tidal estuary with sediments which are highly contaminated with polychlorinated biphenyls (PCBs) and heavy metals. At least two manufacturers in the area used PCBs while producing electric devices from 1940 to the late 1970s, when the manufacture of PCBs was banned by the EPA. These facilities discharged industrial wastes containing PCBs directly into the harbor and indirectly through the city sewer system. As a result, the harbor is contaminated in varying degrees for at least 6 miles from the upper Acushnet River into Buzzards Bay. Over 100,000 people live within 3 miles of the site.

This site is being addressed in four stages: initial actions and three long-term remedial phases focusing on the hot spot area, the upper and lower harbor areas, and the outer harbor Buzzards Bay area.

When the cleanup began, the areas with the highest levels of PCBs were addressed first. A 5-acre northern portion of the Acushnet River estuary was identified as the "hot spot" area and addressed prior to the start of the full scale dredging in the upper and lower harbor that has been underway since 2004. Studies for the nature and extent of contamination in the outer harbor are under way.

Environmental monitoring results indicate that tidal action transports up to 0.5 pounds of PCBs from the upper harbor to the lower harbor each day. Recent monitoring at the Hurricane Barrier indicates that 95 pounds move from within the harbor to Buzzards Bay each year.

Bioaccumulation of PCBs within the marine food chain has resulted in closing the area to lobstering and fishing, and recreational activities and harbor development have been limited by the widespread PCB problem. Since 1982, signs warning the public of the presence of PCBs in the harbor have been in place and maintenance and replacement of these continue as needed.

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Annual Seafood Monitoring

To ensure that the there is adequate information about the levels of PCBs in locally caught seafood, EPA monitors data collected each year by the Massachusetts State Department of Environmental Protection. Multiple sample areas in and around New Bedford Harbor are revisited each year to collect good comparable data. Multiple samples of locally found fish and shellfish are studied each year to see if the cleanup work is having an impact on PCB levels, and to ensure that the public has the most up to date information on which fish are not safe to eat.

EPA Locally Caught Seafood Guidance

Annual Seafood Monitoring Reports:

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EPA Harbor Dredging

EPA has been performing hydraulic dredging of the harbor since 2004. This dredging process removes contaminated sediment and silt from the harbor bottom through a vacuum like network of the dredges, pipelines and filtration facilities. After being de-sanded to remove shells and coarser sand material, and dewatered to remove the excess water, the remaining hard packed contamination is shipped offsite for licensed disposal in Michigan. Through this and all other cleanup work, EPA maintains rigorous environmental monitoring efforts to ensure the project progresses safely for workers and surrounding communities.

Environmental Monitoring Data

While the risk from the consumption of contaminated fish and shellfish is one of EPA's greatest concerns at this Superfund site, we continue to take all other potential environmental and public health impacts seriously. The reports and data provided here for air, water and sediment quality, help EPA track the cleanup progress and ensure that the work is protective of public health and the environment.

Fish Migration

Air Monitoring

EPA performs air monitoring during the active cleanup of New Bedford Harbor to confirm that the dredging, de-sanding, de-watering or water treatment operations do not cause elevated levels of airborne PCBs that could pose an unacceptable risk to public health. To date all of the results during the hydraulic dredging operations have been well below risk based levels of concern.

See the typical cleanup season air monitoring locations around the harbor.

Water Quality Monitoring

The water quality of New Bedford Harbor is monitored one-week before dredging starts to determine existing conditions, as well as during cleanup work. EPA studies water quality to check for potential unintended impacts and to verify that the cleanup work is not creating conditions which could cause toxicity to marine organisms, contaminant movement or interference with seasonal bird and fish migrations within the Acushnet River and harbor.

Environmental scientists monitor water quality by: (i) boat-based measurement of turbidity and documenting fish and wildlife passage close to the dredge activity and further away, (ii) collecting stationary monitoring data from moored water quality sensors to supplement the boat-based monitoring, and (iii) collecting water samples to test the physical, chemical, and biological conditions in the harbor to verify the protectiveness of the project-based cleanup goals.

Sediment Trap

EPA collects additional information about sediment that may move through the water from natural events such as currents and tidal flow, or man-made activity such as boating or dredging. When the sediment settles back down on the harbor bottom it can be trapped and monitored to determine its amount and potential concentration of PCBs. Sediment trap samples are collected during active dredging periods and during the de-mobilization of dredge-related equipment.

North of Wood Street Monitoring

Located at the far northern end of the upper harbor is the North of Wood Street study area. This area extends for about a quarter of a mile north of the Wood Street Bridge between New Bedford and Acushnet, Massachusetts. The intertidal zone, shoreline, in-river sediment and marsh soil in this area was prioritized early on for cleanup and restoration activities based on the high levels of PCB contamination and the close proximity to shoreline residential and recreational land use. During the winter of 2002-2003 about 15,000 cubic yards of material was removed from the area. See photos of the cleanup.

Sampling occurs on an annual, or as needed basis, as part of an environmental monitoring program to assess any potential recontamination from tidal sediment transport from areas in the harbor that are undergoing or awaiting cleanup. Twenty-one locations have historically been sampled: 12 sediment stations in the river, 6 soil locations in the marsh area that was cleaned up on the east side south of River View Park, and 3 shoreline stations on the west side of the river. These stations were last sampled in April of 2010.

Sawyer Street Groundwater Monitoring

In addition to serving as the location of site project offices, the Sawyer Street facility houses the sediment de-sanding operation, a preliminary step in the process of PCB removal in the sediment and is the support area for the harbor cleanup. The area serves as an active PCB material stockpiling, storage, trucking and processing zone. More information about the use of this site is available in EPA's March 2010 Explanation of Significant Differences document (PDF) (16 pp, 1 MB).

There are six groundwater wells located at the perimeter of site to evaluate the integrity of storage areas and confirm that the stored contamination is not migrating or posing a risk to human health and environment. The groundwater monitoring as well as ambient air monitoring for PCBs and VOCs provide additional assurance that the facility is functioning as expected. Stormwater runoff is also stored in an additional holding cell and is tested and treated if necessary prior to being discharged into the harbor. No releases of contaminants from the area that exceed established risk levels have been documented to date, see below for monitoring results. The final remedy for addressing the stored contamination will be addressed in a future Superfund decision document.

Sediment Dredging Progress Monitoring

Collecting sediment samples with a push core sampler.
Collecting sediment samples with a push core sampler.

Sediment samples are collected before, during and after each cleanup season as one of the fundamental ways to track the progress and final results of the dredging operations. Environmental scientists study the sediment samples to identify the concentration of PCBs or other contaminants in the sediment. These samples provide vital information for EPA to determine extent of cleanup success and develop the dredge plan for the upcoming year.

See below for early sediment sampling information.

2012 Near-Shore Boring Program Adjacent to the Former Aerovox Facility

The former Aerovox facility was the primary source of PCBs discharged to the Acushnet River and New Bedford Harbor.  In 2012, twelve sediment/soil borings were advanced to bedrock in the near-shore area adjacent to the former Aerovox facility to obtain a vertical profile of remaining PCBs and select solvents in and under the marine sediment.  The 2012 boring program provided an updated examination of the near-shore sediment contamination in New Bedford Harbor, abutting the Aerovox Site.  The results of this boring program will be used in the design and scheduling of further dredging along the shoreline as part of the overall remediation of the New Bedford Harbor Superfund Site.

Annual Dredging Reports

Annual dredge reports are generated by the project team to provide documentation of the key activities performed and the progress achieved at the New Bedford Harbor site. These reports, sometimes called After Action Reports, are generated after a dredging cycle has been completed. Below are the reports from harbor dredge seasons since 2004 as well as reports from the hot spot dredging in 1997, north of Wood Street dredging in 2002 and north lobe dredging in 2005.

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State Enhanced Remedy

The State Enhanced Remedy (SER) consists of navigational dredging and disposal activities within the New Bedford Harbor Superfund Site. Consistent with CERCLA and its implementing regulations, the Commonwealth of Massachusetts requested that EPA include the SER work in the remedy for the Upper and Lower Harbor (Operable Unit 1). After public review and comment, EPA integrated the SER into the 1998 Record of Decision for the Upper and Lower Harbor. Among other things, the SER benefits the remedy because navigational dredging removes sediment in the lower harbor contaminated with PCB concentrations up to 50 ppm and heavy metals that are below EPA's cleanup levels and that would not be otherwise addressed. SER work began in 2004.

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Additional Long Term Monitoring Activities

Harbor bottom cross-section taken with sediment profile camera.
Harbor bottom cross-section taken with sediment profile camera.

In order to assess the effectiveness of the New Bedford Harbor Superfund cleanup efforts, a long-term environmental monitoring program has been in place since 1993. This is an intensive sampling and analysis effort conducted to quantify the environmental effects of reduced PCB levels in the sediment and water column of the New Bedford Harbor estuary as a result of the cleanup efforts. To date, five sampling events of this kind have taken place to monitor the physical, chemical and biological changes in the harbor. The initial, or baseline, round of sampling occurred in October 1993 (reported in Baseline Sampling, October 1996) and represents conditions prior to cleanup work. A second event was conducted immediately following the removal of "hot spot" sediment in 1995 (results were not compiled into a separate report but information about the results may be found in the 1998 ROD for this site, specifically pages 14 and 15 and Figures 18 - 20c) and a third event in 1999 (reported in Survey III: Summary Report, March 2001). The most recent sampling efforts occurred in 2004 (reported in Survey IV: Summary Report, December 2005) when limited dredging had occurred and in 2009 (reported in Survey V: Summary Report, November 2010), five years after the start of the full-scale dredging process that is currently being used to address the contamination in the upper harbor.

The sampling effort includes multiple stations within the designated project areas:

  • Area 1 (upper harbor) - Wood Street to the Coggeshall Street Bridge (27 stations)
  • Area 2 (lower harbor) - Coggeshall Street Bridge to Hurricane Barrier (29 stations)
  • Area 3 (outer harbor) - Hurricane Barrier to edge of Fishing Closure Area 3
    See the latest seafood guidance (23 stations)

In addition to the monitoring reports shown below, for an illustrated summary highlighting the results of the program, see the April 29, 2010 presentation (PDF) (22 pp, 24.3 MB).

Long Term Harbor Monitoring Program

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Outer Harbor Study

Starting in late 2009, EPA initiated a Remedial Investigation/Feasibility Study (RI/FS) of approximately 17,000 acres located south of the hurricane barrier, known as the outer harbor. The RI/FS includes field sampling activities to determine the nature and extent of contamination, a risk assessment, a review of technologies and range of response actions to address any risk found. Completion of the RI/FS for the outer harbor is currently estimated for the year 2012. EPA will continue to keep the public informed about the progress of the outer harbor study at the monthly public meetings.

Pilot Underwater Cap Monitoring

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Earlier Cleanup Actions

Hot Spot Cleanup

The EPA's original 1990 remedy for the hot spot area included dredging and on-site incineration of those PCB-contaminated sediments above 4,000 ppm. Due to a vehement and congressionally-supported reversal of local support for incineration, EPA elected to postpone the incineration component of the hot spot remedy and explore alternative treatment approaches. Dredging of the 14,000 cubic yards of sediment from the 5 acre hot spot areas was accomplished from April 1994 to September 1995, with the dredged sediment temporarily stored in a lined and covered holding pond. Seawater removed from the sediments during dredging was treated on site. Pilot studies of solidification and chemical destruction technologies were completed in the fall of 1996, and a feasibility study of alternative remedial approaches was issued in December 1997. EPA issued an Amended Record of Decision (ROD) in April 1999 which included dewatering and off-site landfill disposal as the final component for the hot spot remediation. Transportation of the hot spot sediment to an offsite TSCA permitted landfill started in December 1999 and was completed in May 2000.

Other Earlier Cleanup Projects & Maps

Early Sediment Sampling Work "Sediment Characterization"

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New Bedford Harbor Five Year Reviews

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Other Relevant Documents

Feasibility Studies/Modeling Studies/Risk Assessments

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