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  SOUTH WEYMOUTH NAVAL AIR STATION


Map this site in Cleanups in My Community
 Weymouth; Abington; Rockland,  Massachusetts
 Norfolk County, Plymouth County
 Street Address:
 Zip Code: 02190
 Congressional
 District(s):

10
 EPA ID #: MA2170022022
 Site ID #: 0101826
 Site Aliases:

 Site Responsibility: Federal

 NPL LISTING HISTORY
 Proposed Date 06/23/1993
 Final Date 05/31/1994

Site Description
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The South Weymouth Naval Air Station (SOWEY NAS), approximately 1,442 acres in size, is located in the towns of Weymouth, Abington, and Rockland. The facility was used continuously until it closed on September 30, 1997 under the Defense Base Closure and Realignment Act of 1990 (BRAC), Public Law 101-510; as part of the BRAC Commissions 1995 Base Closure List (BRAC IV). The land surrounding the site is suburban, with a mixture of residential, industrial, and commercial uses. After acquiring the site in 1941, the U.S. Navy used it as a Lighter than Air facility for dirigible aircraft used to patrol the North Atlantic during World War II. The facility was closed at the end of the war, then reopened in 1953 as a Naval Air Station for aviation training. The mission of SOWEY NAS was to train all assigned units for their mobilization assignment and to provide administrative coordination and logistic support to the Marine Air Reserve Training Detachment. Activities performed at the site included aircraft maintenance, refueling, personnel training and housing, and administrative support services. The wastes generated by the facility were reportedly disposed in three on-site landfills. The West Gate landfill operated from 1969 to 1972, and the Rubble Disposal area and the Small Landfill operated from 1972 until the mid-1980s. Flammable liquid wastes reportedly were burned at the fire training area, and small amounts of waste battery acid, possibly containing lead, may have been disposed in the tile leachfield. In addition, the U.S. Coast Guard operates a buoy maintenance depot on the property through an agreement with the Navy. At the Coast Guard's buoy depot, lead-based paint from buoys was reportedly sandblasted from 1972 until 1986. Eighteen municipal drinking water wells, located within four miles of source areas at SOWEY NAS, provide drinking water to approximately 74,000 people. In addition, approximately eighty five private drinking water wells located within four miles of SOWEY NAS draw from the same aquifer. Large wetlands occur throughout the surrounding towns, including the Weymouth Great Pond to the west, a source of municipal water for much of the area.

Threats and Contaminants
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Soil samples, collected during the 1991 site investigation were found to be contaminated with volatile organic compounds (VOCs) and heavy metals. Groundwater samples collected near the West Gate landfill, the Rubble Disposal area, the fire fighting training area, and the tile leachfield are contaminated primarily with heavy metals. There are recreational fisheries and wetlands along the Old Swamp River and French Stream/Indian Head River watersheds. Ingesting or directly contacting the contaminants in the soil or groundwater could pose a health risk.

Cleanup Approach
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EPA is addressing the site in two stages: initial actions and a long-term remedial phase that focuses on cleanup of the entire site.

Response Action Status
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Initial Action In 1986, two drums containing PCB-contaminated soil from a leaking transformer were removed to an off-site facility for disposal. An overflow of 5,000 gallons of jet fuel occurred in December 1986 and was cleaned up to meet the requirements of the Massachusetts Department of Environmental Protection. In 1992, during demolition of a secondary containment area at the former sewage treatment plant, several empty pesticide containers and two compressed gas cylinders (one with chlorine) were unearthed. The soil, cylinders, containers, and debris were excavated. In addition, the chlorine cylinder was containerized and removed from the site.

Entire Site The Navy completed the preliminary site assessment in 1988 and a site investigation in 1991. A Phase I Remedial Investigation (RI) was completed in January 1997. Studies of the nature and extent of site contamination and the most appropriate cleanup options are currently underway. The Navy has completed the Final Phase II Remedial Investigation (RI) reports for ten CERCLA sites, including the Small Landfill, Rubble Disposal Area, West Gate Landfill, Fire Fighting Training Area, Tile Leach Field, Sewage Treatment Area, Abandoned Bladder Tank Fuel Storage Area, Building 81, Building 82 and the Solvent Release Area.

The West Gate Landfill (WGL) The WGL was active for approximately 30 years (from 1940's through 1972). The landfill was used primarily for domestic wastes, and occasionally other waste generated on-site. The area of the WGL is approximately 5.2 acres, with an average thickness of 10 feet. The estimated volume of fill is 85,000 cy. Potential health risks posed under the current site use (i.e., on-site worker, trespassing child, and utility/construction worker) exceeded EPA's acceptable risk range. Similarly, potential risks posed under hypothetical future site uses (i.e., on-site resident and recreational child), also exceeded EPA's acceptable risk range. The chemicals contributing most to these potential human health risk exceedences are PCBs and lead in surface soil, and dibenz(a,h)anthracene, arsenic, and chromium in groundwater. Ecological risks also exceed regulatory risk thresholds and are primarily from several metals (aluminum, cadmium, chromium, copper, iron, lead, mercury, nickel, and zinc) in surface soil, as well as the presence of PAHs, PCBs, and dioxin in surface soil. The Navy completed a draft final Feasibility in March, 2002. A Record of Decision for a cap was signed on September 28, 2007. Initial site preparation, including clearing and grubbing, began in December 2008. An ESD was signed in September 2010. Construction activities were completed on September 29, 2011. Ongoing activities associated with the WGL include monitoring and watering (when needed) of the vegetation planted for restoration of the area and post-closure maintenance and monitoring, as described in the March 2011, "Final Post Closure Maintenance and Environmental Monitoring Plan" (PCMEMP).

The Rubble Disposal Area (RDA) The RDA is an inactive landfill, that was used between 1959 and 1962, and again for a short period in 1978. It is approximately 3.83 acres, and 8 feet thick. The estimated quantity of fill within the landfill is 50,000 cy. Potential risks posed under the current site use (i.e., on-site worker, trespassing child, and utility/construction worker) did not exceed EPA's acceptable risk range. For the hypothetical future site use selected (i.e., on-site resident and recreational child), arsenic and manganese were present in groundwater at concentrations that pose a potential risk from groundwater ingestion. Potential ecological risks are posed by the presence of PCBs in surficial media and small mammals; however, that presence of PCBs does not impact the food chain, and does not exceed risk thresholds for higher trophic-level mammals, such as hawks and foxes. The Navy completed a final FS in March 2002. EPA signed the Record of Decision on December 31, 2003. The remedy includes excavation and off-site disposal of PCB-impacted soil from a wetland area, construction of a soil cover over the former disposal site and the use of institutional controls to limit groundwater and land use. In 2007, the RDA was covered by a vegetated soil cap and a 30-year long-term monitoring (LTM) program commenced. An Explanation of Significant Differences (ESD) was completed in August 2010 to add a MNA groundwater remedy and adjust land use control boundaries. The Navy is currently performing LTM, including landfill gas monitoring, consistent with Massachusetts post-closure regulations. A supplemental landfill gas investigation was performed from June to September 2010 to evaluate consistent increases in methane gas concentrations emanating from the RDA. The Navy is currently designing a corrective action to mitigate gas migration from the RDA.

The Small Landfill (SL) The SL was used for five years during the 1980s for disposal of concrete rubble and tree stumps. It is approximately 0.8 acres in area, and 9 feet in depth. The estimated quantity of fill within the landfill is 12,000 cuyds. Potential risks posed under the current site use (i.e., on-site worker, trespassing child, and utility/construction worker) did not in exceed EPA's acceptable risk range. Similarly, potential ecological risks do not exceed EPA's target indices. Conservative future risks were also calculated (i.e., on-site resident and recreational child). Thallium and zinc were present in groundwater at concentrations that pose a potential risk from groundwater ingestion. However, potential risks would not likely exceed EPA's acceptable risk range because (a) the zinc value that drove the risk calculation is not representative of groundwater conditions, it is the result of zinc galvanization resulting from a zinc galvanized steel well point and (b) thallium was reported in only one monitoring well at SL and the reported value was near the quantitation limit. Thallium was not reported in the soil or subsurface soil. A No Further Action Record of Decision was signed in February 2002.

The Fire Fighting Training Area (FFTA) The FFTA was used between 1950 and 1986, and then again in 1988 until operations ceased in 1990. An estimated 500 to 1,500 gallons of fuel per month were used for training. Under both current and future site use scenario there are no exceedences of regulatory risk thresholds. Potential ecological risks do not exceed regulatory risk thresholds. A No Further Action Record of Decision under CERCLA was signed in September 30, 2004. Petroleum residuals at the site will be addressed under applicable Massachusetts state law.

The Tile Leach Field (TLF) The TLF was used for disposal of sanitary wastes from 1945 through 1968. Under both current and future site use scenario there is no exceedence of regulatory risk
thresholds. Potential ecological risks do not exceed regulatory risk thresholds. A No Action Record of Decision was signed in May 2006.


The Sewage Treatment Plant (STP) The STP operated from 1953 to 1978. Potential risks posed under the current site use (i.e., on-site worker, trespassing child, and utility/construction worker) were within the EPA's acceptable risk range. Conversely, potential risks posed under a hypothetical future site use (i.e., on-site resident and recreational child), exceeded the acceptable risk range. The chemicals contributing most to the potential human health risk exceedences are dieldrin in surface soil, arsenic in groundwater and surface water, and chromium in groundwater. There is a potential ecological risks to terrestrial and wetland wildlife at the site that are associated with exposure to organochlorine pesticides in the food chain, including dieldrin and 4,4'-DDT. The Navy completed a Draft Feasibility Study in July 2002. A Record of Decision was signed on April 30, 2008. While most of the contaminated soil has been excavated, construction is currently underway and petroleum contaminated soils remain.

The Abandoned Bladder Tank Fuel Storage Area (ABTFSA) The ABTFSA was used to temporarily store aviation fuel in four fabric bladders, located within an earthern berm. Under both current and future site use scenario there is no exceedence of regulatory risk thresholds. Potential ecological risks do not exceed regulatory risk thresholds. A No Further Action Record of Decision was signed on May 2, 2003.

Building 81 The pilot test to assess applicability of in-situ chemical oxidation treatment for (VOCs) in groundwater near Building 81, started in September, 2000. The process used at Building 81 is Fenton's reagent that is composed of hydrogen peroxide with iron sulfate as the catalyst. A radius of influence of approximately 15 feet in the overburden injectors and a radius of influence of approximately 50 feet in the bedrock injectors was observed. The primary injection period ended on November 1, 2000. The seven-day compliance monitoring began during the week of November 13, 2000. The results showed that there was a major reduction of chlorinated volatile organics (cVOCs) in all the monitoring wells. Thirty-three of the forty of the wells reached the treatment goal of less than 100 ppb of cVOCs. The results of the 60-day post treatment sampling, however, showed significant rebounding in the central area of the plume. Re-injection of Fenton's reagent occurred in late March and early April 2001. There was a 45 day and 100 day sampling event after the two week injection period. The results again showed significant rebounding in 6 to 8 wells located along the axis of the plume. The pilot study is completed and a remedial investigation will be completed. A final RI and final FS were issued in October 2011 and April 2013, respectively. Remedy selection is planned for summer 2013.

United States Coast Guard Buoy Depot Lead in sediment posed a significant risk for resident children and adults. Chromium, copper, mercury and zinc concentrations pose potential risk to avian receptors. The USCG completed a draft FS in March 2001. The USCG completed the storm water system and the swale removal and restoration in December 2004. A Record of Decision (ROD) was signed in September 2006 that required land use controls (LUCs), long-term monitoring, and five-year reviews. The first, Five-Year Review was approved by the EPA on February 23, 2012, confirming that the September 2006 remedy remained protective of human health and the environment, per requirements set forth in the ROD.

Building 82 Chlorinated solvents were detected in soil and groundwater samples. The Navy issued a final RI in February 2010. The Navy completed a RI Addendum and maintenance action in October 2011 to address data gaps remaining after the RI was finalized. The Navy issued the final FS and PP in July 2012. A Record of Decision was signed in September 2012 that required in-situ treatment of shallow and deep groundwater, land-use controls (LUCs), long-term monitoring, and five-year reviews..

AOC 55A and 55B A Record of Decision was signed on October 20, 2004 for Area of Concern (AOC) 55A (North of Trotter Road - Antennae Field) and AOC 55B (North of Trotter Road - Debris Field) . The ROD presents a No Further Action decision for AOC 55A and a No Action decision for AOC 55B under CERCLA. No unacceptable risks were identified at AOC 55A or AOC 55B, except for a slight risk to future residents associated with manganese ingested via groundwater at AOC 55B. However, the presence of manganese in groundwater is consistent with regional background conditions. No unacceptable ecological risks were identified at AOC 55B. After the successful completion of a removal action (excavation of soil and sediment as well as removal of antenna poles), no unacceptable ecological risks remain at AOC 55A.

AOC 35 AOC 35 is the former location of the Pistol Range Building (Building No. 109) that was demolished after 1985. The large embankment south of the building, originally a de-arming embankment, forms the boundary between this area and the East Mat. The north side of the embankment was used as a backstop for the pistol range, a small arms practice area. In June 2000, the Navy removed approximately 134 tons of lead-contaminated soil. The cleanup goal (300 ppm) for lead was achieved for the soil. The Navy properly closed the inactive pistol range, and removed the pistol range/dearmament embankment in December 2003. There was no evidence of unexploded ordinance or related constituents. A No Further Action ROD was signed in February 2005.

Main Gate Encroachment Area The main Gate Encroachment Area is approximately 0.36 acres off of Route 18 in the northwest portion of the base. Contamination from an adjacent property abutter appears to have encroached onto Navy property. Pesticides, PAHs, and metals have been detected. A removal action was completed in July 2011. A No Further Action ROD was signed in September 2011.

AOC 3, 13, 15 and 100 A No Further Action Record of Decision was signed in May 2006 for AOC 3, (the Suspected TACAN Disposal Area), AOC 13 (the Supply Warehouse Railroad Spur), AOC 15 (the Water Tower), and AOC 100 (the East Street Gate Area). Removal actions were completed at all of these areas.

AOC 55D, 8, 4A, & 53 Various removal actions conducted at these sites addressed site risks. A public hearing was held on July 19, 2007. No Further Action Records of Decision were signed in March 2008 for all four sites.

Solvent Release Area The Solvent Release Area, AOC 108, is located south of Pidgeon Road, north of the former Navy pistol range (AOC 35). As part of the Phase II EBS, soil sample BG-05 was collected and was intended to be used to assess background soil conditions. A trace level of tetrachloroethene (below regulatory standards) was detected in the subsurface soil sample from boring BG-05. Navy reservists used this area of the base to conduct weekend field activities. Based on the potential that gun cleaning or other activities may have occurred, the area was added to Phase II EBS program and designated RIA 108. Further samples were collected to confirm that the tetrachlorethene result was valid. The Navy subsequently sampled a downgradient well at the pistol range and found levels of tetrachloroethene that were above screening criteria. In the late Fall of 2003, the Navy conducted a field screening study using a Geoprobe, and based on those results installed seven monitoring wells in 2004. Preliminary results from those wells confirm that groundwater contamination with chlorinated solvents, primarily tetrachloroethene, is present, with the most elevated concentrations near the original BG-05 location. A revised final RI and and final FS were issued in August 2010 and December 2012, respectively. A Proposed Plan was issued in February 2013, A Record of Decision is expected in summer 2013.

AOCs 60 & 61 Various removal actions conducted at these sites addressed site risks. A public hearing was held on October 16, 2008. No Further Action Records of Decision were signed in March 2009 for both sites.

Environmental Progress
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The removal of hazardous materials from the SOWEY NAS site has reduced immediate threats to the public and the environment. Additional studies are underway.

Current Site Status
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The South Weymouth Naval Air Station (SOWEY NAS) was administratively closed on September 30, 1997 under the Defense Base Closure and Realignment Act of 1990 (BRAC), Public Law 101-510, as part of the BRAC Commission’s 1995 Base Closure List (BRAC IV). The facility was operationally closed on September 30, 1996.

A Federal Facility Agreement was signed in November 1999 and became effective in April 2000. This agreement establishes the Navy as the lead agency for the environmental investigation and cleanup of designated sites within the approximately 1400-acre SOWEY NAS property, with EPA oversight.

In March 1998, an initial reuse plan was approved by a three-town vote for office/retail use, senior housing, golf course, and ballfields. EPA encouraged a new developer to incorporate many of EPA's Smart Growth concepts into a revised reuse plan. This new reuse plan was approved by the three affected towns in the summer of 2005. Over 600 acres have already been transferred to the local reuse authority, the U.S. Coast Guard, and the Federal Aviation Administration. On November 15, 2011, a Purchase and Sales Agreement was signed by the Navy and local reuse authority for the remaining 834 acres of the base. Approximately 708 acres (of the 834 acres) are currently available for transfer and 126 acres will be leased until the property has been cleaned up or closed out and deemed suitable for transfer by the EPA. To date, the Navy has spent approximately $66 million on investigation and cleanup activities at the former SOWEY NAS.

Site Photos
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Links to Other Site Information
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Disclaimer Instructions about PDF

Newsletters & Press Releases:
Press Releases about this project  
Proposed Plan for Main Gate Encroachment Area - Operable Unit 26, July 21, 2011 (992 KB)  
Proposed Plan for Building 82 (Hangar 2) - Operable Unit 11, July 1, 2012 (12.7 MB)  
Announcement of Public Meeting for the Proposed Plan, August 9, 2012 (37.5 KB)  

Federal Register Notices:
Final NPL Listing  

Reports and Studies:
Draft Five Year Review, January 01, 2009 (18.5 MB)   
Five Year Review, July 01, 2009 (12.4 MB)  
Five Year Review, US Coast Guard Bouy Depot, Operable Unit (OU) 10, February 23, 2012 (12.6 MB)  
Final Feasibility Study (FS) Report - Building 82, July 2012 (14.4 MB)  
Site Management Plan Revision #12, August 1, 2012 (2.61 MB)  
Feasibility Study (FS) Report for Site 11, Solvent Release Area, December 1, 2012 (Opening file is 6.22 MB with a link to an additional PDF file)  
Feasibility Study (FS) Report for Building 81 with Navy Responses to Comments, April 1, 2013 (51.9 MB with links to additional PDF files)  
Second Five Year Review Report, August 11, 2014 (28.3 MB)  

Decision Documents:
View Records of Decision (RODS) on-line (EPA HQ)  
Click to View all Decision Documents  

Other Links:
NPL Site Narrative at Listing:  
Site Progress Profile  
Please Edit this Label  
South Weymouth Naval Air Station Web Page  
South Shore Tri-Town Development Corporation Web Page  

Site Repositories
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Tufts Library, 46 Broad Street, Weymouth, MA 02188 781-337-1402
Rockland Memorial Public Library, 366 Union Street, Rockland, MA 02370 617-878-1236
Burton Wales Public Library, 33 Randolph Street, Abington, MA 02351 617-982-2139


Contacts
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EPA Remedial Project Manager: Carol Keating
Address: US Environmental Protection Agency
5 Post Office Square, Suite 100
Mail Code OSRR07-3
Boston, MA 02109 - 3912
Phone #: 617-918-1393
E-Mail Address: keating.carol@epa.gov

EPA Remedial Project Manager #2: Kymberlee Keckler
Site Responsibilities: AOC 55C
Address: US Environmental Protection Agency
5 Post Office Square, Suite 100
Mail Code OSRR07-3
Boston, MA 02109 - 3912
Phone #: 617-918-1383
E-Mail Address: keckler.kymberlee@epa.gov

EPA Community Involvement Coordinator: Pamela Harting-Barrat
Address: USEPA REGION 1 - New England
5 Post Office Square
Mail Code: ORA20-1
Boston, MA 02109-3912
Phone #: 617-918-1318
E-Mail Address: harting-barrat.pamela@epa.gov

State Agency Contact: Dave Chaffin
Address: 1 Winter Street, Boston MA 02108
Phone #: 671-348-4005
E-Mail Address: david.chaffin@state.ma.us

 


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