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Installation Restoration Program (IRP) Sites.

This page contains an overview of the Installation Restoration Program (IRP) Sites at Naval Submarine Base New London. The sites are organized in the table below by site name and include a description, summary of investgations and actions, and site status for each site. Scroll down to view all of the sites.

Site Boundaries (PDF)

Site Name Description Summary of Investigations and Actions

Site Status

Site 1: Construction Battalion Unit Drum Storage Area Drums of waste oil, lubricating oil, and paint materials were found on site in the 1980s. The site was approximately 15 feet by 30 feet. Drums were subsequently removed from the site.

·      Low concentrations of volatile organic compound (VOCs) and semivolatile organic compounds (SVOCs) were found in soil and groundwater at this site.

·      A human health risk assessment concluded that no health risks were present at the site.

·      An ecological risk assessment concluded that the site did not provide a significant habitat for terrestrial plants and animals.

·        A No Further Action (NFA) Record of Decision (ROD) was signed in September 1996.

·        A cap constructed for Site 2A landfill covered Site 1. Construction of the cap was completed in 1997.

·        Site closeout milestones reached for site soil include Response Complete and Site Closeout.

Site 2A: Area A Landfill The Area A Landfill, covering approximately 11 acres, operated from approximately the late 1950’s through 1973. Residue from an on-base incinerator was placed at Site 2A (and also Sites 6 and 8). The incinerator closed in 1963, and the landfill received refuse and debris from 1963 until it was closed in 1973. After closure of the landfill, a concrete pad was constructed on the site for storage of industrial wastes. In the early 1980’s, transformers and electrical switches stored on the pad were found to be leaking and a former oil leak was evident. Further, it was reported that spent sulfuric acid from batteries used on the submarines was disposed in the landfill by pouring it into dug trenches and covering it with soil.

·      Shallow groundwater contamination (VOCs, PCBs, and inorganics) was present at the site.

·      PCBs in landfill soil were identified to be a potential threat to human health.

·      Contaminants were identified in soil that could potentially impact the environment.

·      A low- permeability cap system with land use controls (LUCs) and groundwater monitoring was identified as the preferred remedial alternative to address the contaminated soil and waste in the landfill.

 

·        A ROD was signed in September 1995 to document the decision to cap the landfill, implement LUCs, and perform groundwater monitoring at the site. The landfill cap was constructed in 1997.

·        Groundwater beneath and adjacent to the landfill has been monitored since 2001. Results indicate that the cap is working properly and that significant contaminant migration is not occurring. A final ROD for groundwater was signed in 2008 that requires continued groundwater monitoring. A LUC Remedial Design (RD) was prepared for groundwater in 2009 and a Remedial Action Completion Report (RACR) was completed in 2010 to document implementation of the remedy.

·        The site closeout milestone reached for site soil and groundwater is Remedy in Place. Site soil and groundwater are currently in Long-Term Management.

Site 2B: Area A Wetland The 26 acre wetland is located north of Area A Landfill. In the late 1950s, dredge spoils from the Thames River were pumped into this area and contained within an earthen dike. It was reported that pesticide “bricks” containing DDT were placed in the wetlands to control mosquitoes. Uncontrolled releases of chemicals from the adjacent Area A Landfill may also have impacted the sediment in the wetland.

·      Significant concentrations of pesticides, PCBs, and PAHs exist in the site sediment. Primary risks are to ecological receptors.

·      Evaluation of groundwater sampling results showed potential risks to hypothetical residents if groundwater is used as a drinking water supply. However, institutional controls prohibit residential development of the site.

·        Further investigation and a Feasibility Study (FS) were conducted to evaluate remedial alternatives required for sediment.

·        A ROD for site sediment is planned in 2010. Sediment remediation and restoration of wetlands at the site will likely be completed in 2011.

·        A final ROD (2008), LUC RD (2009), and RACR (2010) were completed for the groundwater at the site. Groundwater and surface water are being monitored at the site. Site groundwater is in Long-Term Management

Site 3A: Area A Downstream Watercourses and Overbank Disposal Area Pond

Site 3 includes several ponds, streams, and wetlands. This 75-acre site receives surface water and groundwater recharge from Sites 2A, 2B, 7, 14, and surrounding areas and conveys them to the Thames Rivers. Historic sources of contamination to the site included application of pesticides, abandoned disposal areas, and the septic system leach fields at Site 7. Additionally, inorganics from river dredge spoils in the Area A Wetland and materials from the Area A Landfill may have contributed contaminants to the site.

 

·      Surface soil and sediments contained notable concentrations of pesticides.

·      The VOCs found in groundwater at the site were found to pose a potential human health risk.

·      An Interim ROD (2004) for Site 3 groundwater documented the decision to implement institutional controls and monitoring.

·      Subsequent monitoring identified TCE and vinyl chloride (VC) in excess of cleanup goals.

·      In 2008, potential vapor intrusion of VOCs was evaluated. Potential health risks were identified and building restrictions were implemented for the affected area.

·        A ROD was signed in March 1998 for dredging, on-site dewatering, off-site disposal of sediment and soil, restoration of wetlands and waterways, and monitoring. The remedy was completed in 2000. Three years of post-construction restoration and monitoring verified the success of site restoration activities.

·        The Site 3A soil and sediment remedial action completed as required under the 1998 ROD is considered to be complete. Site closeout milestones reached for soil and sediment are Response Complete and Site Closeout.

·        The final ROD for Basewide Groundwater was signed in September 2008 and documented the decision to monitor Site 3 groundwater until all cleanup goals are met. A LUC RD was prepared for groundwater in 2009 and a RACR was completed in 2010 to document implementation of the remedy. Site groundwater is in Long-Term Management until cleanup goals are met.

Site 3A: ESD Soils During remediation of Site 3A soil and sediment, buried pipes that contained contaminated soil were found that could not be removed without compromising the integrity of the Area A Dike. The soil and pipe was subsequently encapsulated with concrete. This area is referred to as “ESD Soils.” ·      Approximately 13 cubic yards of contaminated soil was encapsulated and left in place.

·        An Explanation of Significant Difference (ESD) was prepared to document the change in the remedy from the Site 3A ROD for soil and sediment.

·        ESD Soils are in Long Term Management (institutional controls and monitoring).

·        Site closeout milestone reached for ESD Soils is Remedy in Place. ESD Soils are currently in Long-Term Management.

Site 3 New Source Area (NSA) Petroleum contamination was detected during the remedial action for Site 3A soil and sediment. Upon further investigation, a small disposal area (i.e., buried drums, cable, etc.) was discovered upgradient of where the petroleum was discovered and determined to be its source. The site was not remediated at the time of the remedial action because the nature and extent of the contamination was not known. Absorbent booms, hay bales, and plastic sheeting were put in place to minimize further contaminant migration during construction activities. ·      Investigation of the site showed that petroleum contamination was released to the soil surrounding the disposal area

·         Because petroleum contamination is not addressed under the ER Program, an NFA ROD was signed in September 2004. However, the petroleum contamination was addressed through a corrective action to meet Connecticut regulations in October 2007.

·         Site closeout milestone reached for Site 3 NSA was ROD.

Site 3B: Overbank Disposal Area (OBDA) Debris The OBDA was located on the slope of the earthen dike below and adjacent to the Area A Landfill. This area was used as a disposal site after construction of the dike in 1957. Uncovered materials, including 200-gallon metal fuel tanks, old creosote telephone poles, empty drums, and scrap lumber were found on the site.

·      Debris from the OBDA area was removed and disposed off site as part of a Non-Time-Critical Removal Action in 1997.

·      Soil potentially contaminated during the decontamination of debris was incorporated into the subgrade of the Area A Landfill prior to capping.

·        An Engineering Evaluation/Cost Analysis (EE/CA) and an Action Memorandum were prepared in 1997 to document the decision process for the Non-Time-Critical Removal Action.

·        Because the debris was removed and disposed of offsite, the site closeout milestone reached for OBDA is Response Complete.

Site 4: Rubble Fill Area at Bunker A-86 Site 4 was a 25-foot by 60-foot plot located in the north-central section of the base. Construction materials including concrete, asphalt, electric motors, wood, and gravel were disposed of at the site. Containers found at this site included chemical corrosives, patching compounds, and lubricating oil.

·      Investigation of the site showed soil samples contained low concentrations of solvents, PAHs, pesticides, and arsenic.

·      In order to install the cap over Area A Landfill and an associated upgradient interceptor trench, Site 4 was excavated and the soil and debris were incorporated into the Area A Landfill cap subgrade. This excavation was completed as a Time-Critical Removal Action.

·        An Action Memorandum was prepared in September 1997 to document the decision process for the Time-Critical Removal Action at Site 4.

·        An NFA ROD was signed in 1998 because all soil and debris were removed from the site.

·        Groundwater in this area is being monitored under the Site 2A groundwater monitoring plan.

·        Site closeout milestones reached for the site are Response Complete and Site Closeout.

Site 6: Former Defense Reutilization and Marketing Office (DRMO) The DRMO, a 3-acre area located next to the Thames River in the northwest section of the Subase, was used from 1950 to 1969 as a landfill and waste-burning area. Non-salvageable waste items including construction materials and combustible scrap were burned along the Thames River shoreline and the residue was pushed into the shoreline and partially covered. A battery acid handling facility was located there, as was a storage tank and pumping facilities for spent acid. Operations were ceased at the site and all equipment was removed in 2-007. The site is currently used by Subase Morale, Welfare, and Recreation Department for storage.

·      Potential human health risks were identified for workers based on elevated concentrations of PCBs, PAHs, beryllium, and lead in the soil. Health and safety precautions were established for site workers to address potential exposure to contaminated surface soils at the site.

·      Groundwater quality was impacted by the contamination, but drinking water wells cannot be located in the affected area because of the proximity to the brackish water of the Thames River.

·      A Time-Critical Removal Action was completed at the site in January 1995. The Removal Action included excavating the contaminated soil and disposing it in an off-site permitted landfill, backfilling the area with clean soil, and covering the backfilled area with an engineered cap system that included three layers of liners (woven geotextile, geosynthetic clay liner, and nonwoven geotextile), 9 inches of crushed stone, and 3 inches of asphalt.

·      Groundwater monitoring was initiated in 1998 to measure the effectiveness of the cover. Results of 11 years of monitoring have not shown any significant contaminant migration issues.

·        An Action Memorandum was prepared in March 1995 to document the decision-making process for the Time-Critical Removal Action at Site 6

·        An Interim ROD, signed in 1998, documented the decision to implement LUCs and groundwater monitoring at the site.

·        A final ROD was signed in 2006 to document the final remedy of LUCs, groundwater monitoring, and five-year reviews for soil and groundwater at Site 6.

·        Site closeout milestone reached for the site is Remedy in Place. Site 6 soil and groundwater are currently in Long-Term Management.

Site 7: Torpedo Shops Site 7, which covers approximately 7 acres, is located in the northern portion of the Subase on the north side of Triton Avenue and includes three buildings. Building 325, a torpedo overhaul facility, was built in 1955 and had an on-site sanitary septic system until 1983. The original septic leach field for the building became clogged and was abandoned in 1975. A new leach field was constructed next to the original leach field and used until 1983 when a sanitary sewer system was installed. A variety of fuels, solvents and petroleum products were used in the building. A sink in one area was used for film development and other was used to overhaul alkaline batteries. Both of these sinks discharged to the septic system. Two fuel oil underground storage tanks were located south of Building 325. One on the tanks was closed in 1995. Building 450 is the torpedo overhaul/assembly facility that generates fuels, solvents, and petroleum products as wastes. Building 477 was used to store fuel and solvents and petroleum products were used in the building.

·      A removal action was completed in 1995 along the southern side of Building 325 to remove soil contaminated with petroleum products associated with the underground storage tanks. This removal was completed under Connecticut regulations.

·      Further investigation showed that contaminated soil remained near Building 325 and contaminated soil and groundwater were present near the abandoned leachfield. The human health risk assessment showed that risks posed by exposure to contaminated soil were generally low for current receptors. However, risks associated with future residential groundwater usage could result in an unacceptable risk.

·      The Remedial Action selected for soil was excavation and off-site disposal and for groundwater was LUCs and monitoring.

·      In 2008, potential vapor intrusion of VOCs was evaluated. Results of the evaluation showed that No Further Action is required for vapor intrusion issues at Site 7.

·        A ROD for Site 7 soils was signed in September 2004 documenting the decision to excavate and dispose soil off-site. The Remedial Action for Site 7 soil, completed in May 2006, included removing 1150 tons of soil and 125 tons of asphalt.

·        A final ROD for Basewide Groundwater, signed in September 2008, documented the decision to implement LUCs, monitoring, and five-year reviews for Site 7 groundwater.

·        A Groundwater Monitoring Plan was implemented in May 2006 and completed in 2008. The monitoring showed that the remedial goals for Site 7 groundwater were achieved. The RACR for Basewide Groundwater (2010) acknowledged the completion of the Site 7 groundwater remedial action and discontinuation of the monitoring, LUCs, and five-year reviews.

·        The site closeout milestones reached for Site 7 soil and groundwater are Remedy Complete and Site Closeout.

Site 8: Goss Cove Landfill Goss Cove Landfill is located off Military Highway in the southwestern portion of the Subase, adjacent to the Thames River. It covers approximately 3.5 acres. From 1946 through 1957 incinerator ash, rubble and other unknown materials were disposed in the northern portion of Goss Cove. The southern portion of Goss Cove was not used for waste disposal and remained open water. The Nautilus Museum (a submarine museum operated by the Navy and open to the public) and its paved parking lot are constructed directly over the former landfill.

·      Site investigations were conducted from 1990-1992 and from 1993-1995. The human health risk assessment showed elevated risks based on PCE in groundwater and PAHs and metals in soil. The source of the PCE was later found to be an upgradient, off-site dry cleaning facility, which was subsequently remediated by the State of Connecticut.

·      Additional investigations and evaluations performed for a 1999 FS showed that contaminant levels detected in sediment and surface water in Goss Cove did not pose potential adverse risks to human health or the environment. The presumptive remedy of capping was determined to be the most appropriate alternative for Site 8 soil/waste.

·      A final investigation of groundwater was completed in 2002 to further evaluate the potential risks to human receptors identified in a previous investigation. The investigation results showed that sources of VOCs, SVOCs, and metals within the waste material were continuing to impact the shallow groundwater at the site. It was recommended that the remedial action for soil/waste (capping, LUCs, and groundwater monitoring) be implemented.

·        A ROD was signed in September 1999 to document the selected remedy for soil/waste of capping, implementing land LUCs, and performing long-term groundwater monitoring. The cap system was installed in 2001, LUCs were implemented and are routinely inspected, and groundwater monitoring is conducted regularly to confirm the effectiveness of the cap.

·        NFA was the selected remedy for sediment and surface water at the site in the 1999 ROD because contaminant levels were shown to pose no risk to human health or the environment.

·        The site closeout status of Site 8 soil and groundwater is Remedy in Place and the current phase is Long-Term Management. The status of Site 8 surface water and sediment is Site Closeout.

Site 9: Oily Wastewater Tank (OT-5) OT-5 was a 750,000-gallon concrete underground storage tank located between Sculpin and Tang Avenues in the southern portion of the Subase. The tank was one of nine tanks in the Site 23 Fuel Farm. The tank had a diameter of approximately 112 feet and was 11 feet deep. The top of the tank was about 5 feet below the ground surface. When tank use ceased in 1993, most of the contents were removed, except for 2-3 inches of sludge containing PCBs. Subsequently, groundwater infiltrated the tank, creating a potential source of contamination to the surrounding soil and groundwater.

·      Investigations and corrective actions for Site 9 soil and sludge were completed under Connecticut regulations.

·        A removal action of the PCB-contaminated sludge was completed in 1994. The removal action included removal and disposal of the sludge, cleaning the tank, crushing the top of the tank, and filling the tank with inert material.

·        Because Site 9 was located within Site 23, the groundwater at the site was combined with Site 23 groundwater and further investigated under the ER Program.

·        NFA is needed for soil under the ER Program at Site 9 to ensure protection of human health and the environment.

·        A final ROD for Basewide Groundwater, signed in September 2008, documented the decision to implement LUCs and five-year reviews for groundwater at Sites 9 and 23. The LUCs prevent the withdrawal and/or use of groundwater for potable water purposes until groundwater concentrations are less than criteria deemed acceptable for unrestricted use and unlimited exposure.

·        A LUC RD was prepared for groundwater in 2009 and a RACR was completed in 2010 to document implementation of the remedy. Site closure status for groundwater is Remedy in Place and the phase is Long-Term Management.

Site 10: Lower Subase-Fuel Storage Tanks and Tank 54-H

Site 10 includes five former concrete underground storage tanks that were placed into service during WWII. Three of the tanks were used to store Diesel fuel and two were used to store lubrication and hydraulic oils. A sixth tank (Tank 54-H) held 30,000 gallons and was used as a reclamation tank for the other five tanks. Tanks E, F, G, and 54-H were decommissioned in 1987. Tanks K and L were decommissioned in 1989 and the shells were used to provide secondary containment for newly installed steel tanks.


Sites 10 and 11 were evaluated collectively as Zone 1 in the Phase II RI, Lower Subase RI, and Lower Subase FS. The Thames River adjacent to Zone 1 was also investigated during the Phase II RI and Lower Subase RI.

·      Investigations of the site conducted from 1983 to 1999 found significant amounts of petroleum contamination in the soil of Site 10 and adjacent Site 11, but concluded that the historical sources of the contamination had been eliminated.

·      A 1997 investigation found petroleum and lead contamination in site groundwater. The associated risk assessment indicated a potential human health risk associated with contaminants at the site. The ecological risk assessment for the Thames River (surface water and sediment) adjacent to Zone 1 indicated that risks to ecological receptors were minor and did not require further action.

 

·        An FS is currently being prepared for Zone 1 soil, groundwater and light non-aqueous phase liquids (LNAPL) at Site 10. It is expected that the FS will be finalized in 2010 and final remedy selection for Zone 1 is expected to be documented in a ROD to be signed in 2011.

·        Current site closeout phase is RI/FS; no site closeout milestones have been reached.

Site 11: Lower Subase Power Plan Oil Tanks

Site 11 includes four 170,000-gallon underground storage tanks (Tanks A, B, C and D) located adjacent to and east of the Subase power plant. Tanks A and B were used to store No. 6 fuel oil pumped from the Tank Farm at the southern end of the Subase. Tanks C was used to store diesel oil, and Tank D was used to store waste oil generated in the bilge water oil recovery system at the power plant. The tanks have been in place since World War II. Past oil leakage was apparent when the old tanks were cleaned; however, the old tanks were repaired and are now used as containment structures for three 150,000-gallon steel underground storage tanks.

Sites 10 and 11 were evaluated collectively as Zone 1 in the Phase II RI and Lower Subase RI. The Thames River adjacent to Zone 1 was also investigated during the Phase II RI and Lower Subase RI.

·      Investigations of the site conducted from 1983 to 1999 found significant amounts of petroleum contamination in the soil of Site 11 and adjacent Site 10, but concluded that the historical sources of the contamination had been eliminated.

·      A 1997 investigation found petroleum and lead contamination in site groundwater. The associated risk assessment indicated a potential human health risk associated with contaminants at the site. The ecological risk assessment for the Thames River (surface water and sediment) adjacent to Zone 1 indicated that risks to ecological receptors were minor and did not require further action.

·        An FS is currently being prepared for Zone 1 soil, groundwater and light non-aqueous phase liquids (LNAPL) at Site 11. It is expected that the FS will be finalized in 2010 and final remedy selection for Zone 1 is expected to be documented in a ROD to be signed in 2011.

·        Current site closeout phase is RI/FS; no site closeout milestones have been reached.

Site 13: Lower Subase-Building 79 Waste Oil Pit

Site 13 (Building 79 Former Waste Oil Pit) consists of the former waste oil pit located in the northwestern corner of Building 79. A railroad spur was located at Site 13, where diesel engines were serviced inside Building 79 during World War II and through the 1950s. The Building 79 service area included a pit in the northwestern corner of the building into which waste oil and solvents were reportedly drained during the cleaning and servicing of diesel engines. The pit is no longer in use and has been filled with concrete. Building 79 is slated to be demolished to grade and the area will be subsequently paved and used for parking.

The Quay Wall Study Area runs from approximately Pier 2 to Pier 6. The wooden platform and quay wall were constructed in 1940. Petroleum impacts were previously visible in the soil immediately above the wooden platform.

Site 13 was included in Zone 4, which also includes Site 19 – Former Solvent Storage Area (Former Building 316), Quay Wall Study Area, and fuel distribution pipeline, for the Phase II RI and Lower Subase RI. The Thames River adjacent to Zone 4 was also investigated during the Phase II RI and Lower Subase RI. Sediment at Inner and Outer Pier 1 and the ecological risks associated with them were further evaluated during a Validation Study.

·      An investigation to identify and delineate the sources of heavy oils in the subsurface of the Lower Subase (Sites 10, 11, and 13) was completed in 1987 and recommended removal of the oil from the manholes near Building 79.

·      During the Phase I RI oil was identified west of Building 79. The report indicated this oil potentially originated from the former waste pit in Building 79.

·      Petroleum impacts were previously identified in the Quay Wall Area adjacent to Site 13 in November 1994. A two-phase removal action was completed to address the petroleum. The stormwater pipe leading to the outfall was abandoned and plugged in December 1994. Free product recovery wells were installed in December 1994 and 18,300 gallons of oily waste water were recovered, treated, and properly disposed of during the actions. During a well inspection conducted in October 2007, no evidence of free product was found in any of the wells.

·      A Lower Subase RI performed in 1999 investigated soil and groundwater. The RI indicated that lead contamination was identified in soil and groundwater. Widespread petroleum contamination was identified in deep soil. Some petroleum contamination was also evident in shallow soil and groundwater. The RI recommended that an FS be performed to evaluate appropriate remedial alternatives.

·      Thames River sediment was further characterized at Zone 4, including Inner and Outer Pier 1, to determine the extent of contamination and evaluate disposal options for the contaminated sediment. It was concluded that concentrations of PAHs, PCBs, pesticides, and metals in Zone 4 and Inner and Outer Pier 1 sediment posed unacceptable risks to ecological receptors. An FS is being prepared for the sediment at Zone 4 and a portion of the sediment at Outer Pier 1. The remaining sediment at Inner and Outer Pier 1 is being addressed through a multi-phase Non-Time Critical Removal Action.

·        An FS is currently being prepared for Zone 4 soil, groundwater, and sediment. It is expected that the FS will be finalized in 2010 and final remedy selection for Zone 4 is expected to be documented in a ROD to be signed in 2011.

·        Current site closeout phase is RI/FS; no site closeout milestones have been reached.

·        An EE/CA and Action Memorandum (2009) were prepared to document the appropriate approach to address Inner and Outer Pier 1 sediment. The initial phase of the removal action for Inner and Outer Pier 1 sediment was initiated in December 2009 and completed in April 2010. The second phase of the removal action is expected to be completed in 2011.

Site 14: Overbank Disposal Area Northeast (OBDANE) The OBDANE site was located in a heavily wooded area on the edge of the ravine north of the Torpedo Shops. Miscellaneous wastes were previously dumped at the site and covered a circular area approximately 80 feet in diameter. A nearly 20-foot-high bedrock face is located in the eastern edge of the site. The rest of the site slopes to the southwest.

·      The Initial Assessment Study suggested that dumping had occurred at the site prior to 1972 and documented the presence of several empty fiber drums.

·      The site was investigated during the Phase I (1992) and Phase II RIs (1997) and the results showed that there were some contaminants (arsenic and lead) in the soil at the site above Connecticut criteria, but human health risks were with generally low and within target ranges. A removal action was recommended for the contaminated soil and debris at the site.

·      Site 14 groundwater was further evaluated in 2002 as part of the groundwater investigation for Site 3 and a supplemental investigation completed in 2004. Results of the human health risk assessment completed for the investigations concluded that there were no significant risks to potential receptors from exposure to Site 14 groundwater.

·        An Action Memorandum for a Non-Time-Critical Removal Action was prepared in 1999 to document plans to remove and dispose of contaminated soil and debris at Site 14. The removal action was completed May 2001.

·        Because no significant risks remained in the site soils after the removal action was completed, a NFA ROD was signed for Site 14 soils in September 2004.

·        Based on the results of groundwater investigations, an NFA ROD was signed for Site 14 groundwater in 2008.

·        The site closeout phase reached for Site 14 soil and groundwater is Site Closeout.

 

Site 15: Spent Acid Storage and Disposal Area Site 15 was located in the southeastern section of the Subase, between Buildings 409 and 410. The site included a concrete storage pad and an underground storage tank that were used for storage and disposal of discarded batteries and battery acid. The acid was periodically emptied from the tank by a pumper trunk and disposed of offsite. The former tank and surrounding area encompassed approximately 1,000 square feet. All battery acid and housing storage at the site was terminated.

·      Based on the results of a 1992 RI and 1994 Focused FS, a removal action for the tank and contaminated soil at the site was recommended. The removal action was completed in 1995.

·      The Phase II RI (1997) found that remaining concentrations of contaminants in soil did not pose a risk of contaminant migration to groundwater. Connecticut Department of Environmental Protection completed an independent investigation of the site in 1997 and confirmed that the soil did not pose any significant risks. Groundwater was investigated in 2002. An additional assessment was also completed to evaluate if volatile compounds could migrate into building foundations, but it showed no concern from contaminants at the site. The final conclusion of the studies was that there were no soil or groundwater contaminants of concern at the site.

·        An Action Memorandum was prepared to document the actions taken during the 1995 Time Critical Removal Action (i.e., remove contaminated soil, pavement, and tank contents).

·        A NFA Source Control ROD was signed in 1997 for the soils at Site 15.

·        A NFA ROD was signed for Site 15 groundwater in 2008.

·        The site closeout milestone reached for Site 15 soil and groundwater is Site Closeout.

Site 16: Hospital Incinerator Site 16 consisted of two former locations where a skid-mounted incinerator was reportedly operated in the 1980s by the Naval Hospital Groton to destroy medical records and medical waste contaminated with pathological agents. The two sites (16-A and 16-B) are located west of Tautog Road, adjacent to Building 449 and Building 452. Ash generated by the waste incinerator was transferred to dumpsters and disposed at a municipal landfill. ·      Soil was investigated in 2002 through an RI. The results of the RI showed that there was no significant impact to surrounding soil and no subsequent rounds of investigation were necessary.

·        Based on the results of the RI, a NFA ROD was signed for Site 16 soil in 2004.

·        The site closeout milestone reached for Site 16 soil is Site Closeout.

Site 17: Lower Subase-Hazardous Materials/Solvent Storage Area (Building 31) Site 17 is the Former Battery Overhaul Shop (Former Building 31), which was constructed in 1917 and used as a battery shop until the mid-1950s. The site is located near Capelin Road and Bullhead Road in the Lower Subase. Spent acid from the overhauled batteries was taken to Site 15 for storage. Building 31 was also used as the main hazardous/flammable materials warehouse for the Subase from the 1970s to late 1990s. Materials such as acids, ketones, and hydroxides were stored in containers of up to 55-gallon capacity. Building 31 was demolished in the late 1990s; however, the concrete floor slab of Building 31 was left in place over the solidified lead-contaminated soil. Asphalt pavement was placed over the floor slab as a protective wearing surface, and the area is currently used as a parking lot.

Site 17 has been investigated as Zone 3 of the Lower Subase, which contains Site 17 – Hazardous Materials/Solvent Storage Area (Building 31) and former subsurface fuel oil distribution lines.

·      During building renovations in 1992, lead-contaminated soil was identified beneath the building floor slab. An Action Memorandum was prepared in 1993 that recommended a Time-Critical Removal Action for the contaminated soil. The removal action was completed in 1995.

·      The 1999 Lower Subase RI indicated that lead is still a concern in soil and groundwater at the site and that petroleum compounds are also of concern in soil. The Lower Subase RI recommended that an FS be prepared for the site.

·      Building 31 was demolished in 2001 and Building 78, which was located adjacent to Building 31, was demolished in 2005. A parking lot was constructed in the area formerly occupied by Buildings 31 and 78.

·        An Action Memorandum was prepared in 1993 to document the actions taken during the 1995 Time-Critical Removal Action (i.e., excavation, onsite solidification of lead-contaminated soil, onsite backfilling, and offsite disposal of impacted debris).

·        An FS is currently being prepared for Zone 3 soil, groundwater, and sediment. It is expected that the FS will be finalized in 2010 and final remedy selection for Zone 3 is expected to be documented in a ROD to be signed in 2011.

·        Current site closeout phase is RI/FS; no site closeout milestones have been reached.

 

Site 18: Solvent Storage Area (Building 33) Site 18 consisted of Building 33, which is located east of Grayback Avenue. Several 55-gallon drums containing solvents such as TCE and dichloroethene and some gas cylinders were stored in Building 33. ·      Soil and groundwater at the site were investigated during a 2002 RI. The results from the RI indicated that past storage of solvents at Building 33 did not significantly impact the surrounding media and that the site does not pose significant risks to any potential human receptors.

·        A NFA ROD for soil was signed in 2004.

·        A NFA ROD for groundwater was signed in 2008.

·        The site closeout milestone reached for Site 18 soil and groundwater is Site Closeout.

Site 19: Lower Subase-Solvent Storage Area (Building 316)

Site 19 (Former Solvent Storage Area) includes former Building 316, which was located south of the gate valve building (Building 332). Various solvents used for equipment cleaning (e.g., 5-gallon cans containing methyl ethyl ketone) were stored in Building 316 until approximately 10 years ago. The roof and doors of Building 316 were recently demolished leaving only the side walls.

Site 19 was included in Zone 4, which includes Site 13 - Building 79 Former Waste Oil Pit, Site 19 – Former Solvent Storage Area (Building 316), the Quay Wall Study Area, and the fuel distribution pipeline, during the Lower Subase RI.

·      The 1999 Lower Subase RI investigated soil and groundwater at Zone 4. The RI indicated that lead contamination was present in soil and groundwater and widespread petroleum compounds contamination was identified in deep soil. Some petroleum contamination was also evident in shallow soil and groundwater. Site 13, as opposed to Site 19, appeared to be the major source of contamination in Zone 4. The RI recommended that the site proceed to an FS to evaluate appropriate remedial alternatives for soil and groundwater.

·      Thames River sediment was further characterized at Zone 4, including Inner and Outer Pier 1, to determine the extent of contamination and evaluate disposal options for the contaminated sediment. It was concluded that concentrations of PAHs, PCBs, pesticides, and metals in Zone 4 and Inner and Outer Pier 1 sediment posed unacceptable risks to ecological receptors. An FS is being prepared for the sediment at Zone 4 and a portion of the sediment at Outer Pier 1. The remaining sediment at Inner and Outer Pier 1 is being addressed through a multi-phase Non-Time Critical Removal Action.

·        An FS is currently being prepared for Zone 4 soil, groundwater, and sediment. It is expected that the FS will be finalized in 2010 and final remedy selection for Zone 4 is expected to be documented in a ROD to be signed in 2011.

·        Current site closeout phase is RI/FS; no site closeout milestones have been reached.

·        An EE/CA and Action Memorandum (2009) were prepared to document the appropriate approach to address Inner and Outer Pier 1 sediment. The initial phase of the removal action for Inner and Outer Pier 1 sediment was initiated in December 2009 and completed in April 2010. The second phase of the removal action is expected to be completed in 2011.

Site 20: Area A Weapons Center Site 20, the Area A Weapons Center, is located north of the terminus of Triton Road, adjacent to the Area A Wetland and includes Building 524 and the northern and southern weapons storage areas. Building 524 is used for administration, minor torpedo assembly, and storage of simulator torpedoes. No weapons production takes place in this building. Chemicals and chemical wastes, including cleaning and lubricating compounds, paints, adhesives, and liquid fuels, were stored in 1-gallon to 5-gallon containers in metal storage cabinets located on a paved area south of the building. Building 524 was constructed in 1990 and 1991. The northern and southern weapons storage bunkers are located southeast of Building 524. Weapons containing liquid fuels such as Otto fuel, JP-10, and TH-Dimer (jet rocket fuel), are stored in these bunkers.

· A Phase II RI in 1997 found a small area of contaminated soil and sediment and minimal contamination of surface water and groundwater existed.

· An FS was completed in 2000 to determine an appropriate alternative for remediating the soil and sediment. A small Remedial Action (less than 200 cubic yards) was conducted at the site in 2001 to address contaminated (PAH and arsenic) soil and sediment.

· Groundwater was further characterized in 2002 during an RI and an additional investigation in 2004. In combination, the results of the investigations showed that there was no significant contamination in groundwater and that there are no significant risks to human health associated with exposure to groundwater. The investigation recommended that an FS not be prepared for groundwater and that an NFA ROD be prepared for the groundwater.

· A study was performed in 2008 to assess if volatile compounds could migrate from groundwater into building foundations. It showed no concern from contaminants at the site.

· A ROD was signed for soil and sediment in June 2000 and a remedial action, that included excavation and off site disposal, was completed in 2001.

· An NFA remedy was selected for Site 20 groundwater in the Final Basewide Groundwater ROD (2008).

· Based on the results of the remedial action at Site 20, the Response Complete milestone was been achieved for soil and sediment. The closeout status reached for site soil, sediment, and groundwater is Site Closeout.

Site 21: Lower Subase-Berth 16

Site 21, Berth 16, is located at the Lower Subase along the Thames River at the intersection of Amberjack Road and Albacore Road. Buildings 106, 157, and 173 were constructed between 1918 and 1944. Buildings 456 and 478 were constructed after the incinerator (Site 25) was demolished in 1979. Berth 16 formerly included a refuse/classified materials incinerator (Site 25), an underground storage tank for storage of diesel fuel, transformers that formerly contained PCB-based oils, and underground diesel fuel lines. All underground diesel distribution lines have been abandoned. A former septic tank with a leaching field serviced Building 173.

Site 21 (Berth 16), Site 25 (Classified Materials Incinerator), and Transformers at Building 157, Vault 31 were investigated collectively as Zone 7 during the Lower Subase RI.

· The area was investigated during the Pier 33 and Berth 16/Former Incinerator Site Investigation (1995) and the Lower Subase RI (1999). A large area of lead contamination was identified in shallow and deep soil in Zone 7. Petroleum contamination in soil was also evident in two general areas. Little organic contamination was identified in the groundwater; however, two areas of lead contamination were identified in Zone 7 groundwater. The ecological risk assessment for the Thames River adjacent to Zone 7 indicated that risks to ecological receptors were low to moderate, but subsequent dredging made interpretation of the results difficult. The Lower Subase RI Report recommended additional characterization of the sediment and Zone 7 soil and groundwater proceed to an FS for evaluation of appropriate remedial alternatives.

· Further investigation of the Thames River sediment was completed as part of the 2008 Validation Study. The study showed that the contaminants present in the Zone 7 sediment did not present unacceptable risks to ecological receptors.

· An FS is currently being prepared for Zone 7 soil and groundwater. It is expected that the FS will be finalized in 2010 and final remedy selection for Zone 7 is expected to be documented in a ROD to be signed in 2011.

· Current site closeout phase is RI/FS; no site closeout milestones have been reached.

Site 22: Lower Subase – Pier 33

Site 22 is located at the Lower Subase along the Thames River and includes Pier 33, Building 175, and approximately 400 linear feet of additional riverfront property adjacent to these two structures. Building 175 was originally used to house several above-ground battery acid (sulfuric acid) storage tanks. Transfer lines from the battery acid storage tanks extended in trenches along Amberjack Road to the piers. The Navy removed the above-ground storage tanks and associated transfer piping. Building 175 is currently used for miscellaneous storage and administrative purposes. A 1,000-gallon underground storage tank was located adjacent to the southern side of Building 175. Because of stained soil around the fill pipe of the tank and concentrations of petroleum compounds in soil exceeded federal and state criteria, the UST was removed and replaced by a new 1,500-gallon above-ground storage tank. A 250-gallon diesel fuel underground storage tank was located adjacent to the northern side of Building 175. This tank was removed and replaced with a 550-gallon above-ground storage tank.

 

During the Lower Subase RI, Site 22 and the surrounding area were identified as Zone 5.

· The area was investigated during the Pier 33 and Berth 16/Former Incinerator Site Investigation (1995) and the Lower Subase RI (1999). The investigations found that petroleum compounds and lead were the primary chemicals of concern for this site. The ecological risk assessment for the Thames River adjacent to Zone 5 indicated that risks to ecological receptors were minor and did not required further action. The Lower Subase RI Report recommended that Zone 5 proceed to an FS to evaluate appropriate remedial alternatives for soil and groundwater.

· An FS is currently being prepared for Zone 5 soil and groundwater. It is expected that the FS will be finalized in 2010 and final remedy selection for Zone 5 is expected to be documented in a ROD to be signed in 2011.

· Current site closeout phase is RI/FS; no site closeout milestones have been reached.

Site 23: Fuel Farm The Site 23 Fuel Farm was constructed in the early 1940s in the former location of Crystal Lake, which was drained and dredged to allow for construction of the nine concrete underground storage tanks. Other tanks, buildings, and recreational field are also located or were formerly located at the site. Each of the nine former tanks had a holding capacity of 750,000 gallons and contained No. 6 fuel oil, diesel, waste oil, or tank bottom wastes. Because of a reduced demand for fuel oil, Tanks OT-1 through OT‑9 have been decommissioned and closed in place following Connecticut closure requirements. The Fuel Farm originally contained an extensive drainage system consisting of numerous catch basins, corrugated metal pipe, perforated corrugated metal pipe, vitrified clay pipe, and reinforced concrete pipe. The surface water and groundwater collected by the storm sewer system ultimately discharged to the Thames River, adjacent to the Goss Cove Landfill (Site 8).

·      A number of petroleum releases were documented at the Fuel Farm and subsequent investigations of the Fuel Farm conducted from 1989 through 1999 detected evidence of releases of petroleum products from these tanks and their associated piping and, possibly, from other nearby sources. Both soil contamination and free-product were identified at Site 23 during the investigations. Petroleum hydrocarbons were historically detected periodically at the outfall of the Fuel Farm storm sewer system.

·      Corrective actions under Connecticut regulations were conducted to address free product and soil contamination at Site 23 in 1997. Approximately 783 tons of petroleum-impacted soil was removed from Site 23 near OT-8 and Tang Avenue during the removal actions.

·      The Fuel Farm drainage system was refurbished in 2000. The original combined groundwater and stormwater system was separated into a deep groundwater collection system and a new shallow stormwater system. As part of the drainage system rehabilitation project, contaminated soil and free product, which were previously identified in the vicinity of former tank OT-3, were removed and disposed off site.

·      Site 23 groundwater, which includes Site 9 groundwater, was further characterized during an RI (2002). The RI results were inconclusive regarding groundwater contamination at Site 23. A quarterly groundwater monitoring program was initiated in 2007 to further characterize the groundwater. Two years of data were collected and the results indicated that the groundwater does not pose a significant threat to human health or the environment under the current land use scenario; however, risks may be unacceptable if the groundwater at the site was used as a drinking water supply.

·      A 2008 study to assess if volatile compounds could migrate into building foundations showed that vapor intrusion is not an issue at Site 23.

·        NFA is needed for soil under the ER Program at Site 23 to ensure protection of human health and the environment.

·        The final ROD for Basewide Groundwater was signed in September 2008 and documented the decision to implement LUCs and five-year reviews for Site 23 groundwater until concentrations in groundwater meet criteria acceptable for unrestricted use and unlimited exposure and ensure that groundwater extracted during construction dewatering activities is properly handled, stored, and disposed. A LUC RD was prepared for groundwater in 2009 and a RACR was completed in 2010 to document implementation of the remedy. Site groundwater is in Long-Term Management until cleanup goals are met.

·        The site close out milestone reached for Site 23 groundwater is Remedy in Place and the groundwater is currently in Long-Term Management.

 

Site 24: Lower Subase-Central Paint Accumulation Area (Building 174)

Site 24 - Central Paint Accumulation Area (Building 174) is located in the northern section of the Lower Subase along the Thames River, immediately east of Pier 32. Building 174 was used as the primary storage facility for paints used in boat maintenance. In 1982, Building 174 was refitted to allow boat anchor sandblasting and other paint activities. Surface water runoff near Site 24 drains to the Thames River via storm sewers/outfalls.

For investigation purposes, Site 24 and the surrounding area were identified as Zone 6 during the Lower Subase RI.

·      The Lower Subase RI (1999) identified petroleum compounds and inorganics as contaminants of concern for the site. The ecological risk assessment performed for the Thames River adjacent to Zone 6 indicated that risks to ecological receptors are relatively low and did not warrant further action. The RI recommended that Zone 6 soil and groundwater proceed to an FS to evaluate appropriate remedial alternatives.

·        An FS is currently being prepared for Zone 6 soil and groundwater. It is expected that the FS will be finalized in 2010 and final remedy selection for Zone 6 is expected to be documented in a ROD to be signed in 2011.

·        Current site closeout phase is RI/FS; no site closeout milestones have been reached.

 

Site 25: Lower Subase-Classified Materials Incinerator

Site 25 consists of the former Classified Materials Incinerator located on the Lower Subase, approximately 300 feet east of Pier 17. Between 1944 and 1963, the incinerator, located within former Building 97, was used to burn classified materials and other nonsalvageable wastes generated at the Subase. Residual ash from the incinerator was disposed in the Goss Cove Landfill. Adjacent to the incinerator was a dumpster cleaning operation. The incinerator was demolished in 1979, and Buildings 456 and 478 were constructed in the areas previously used for the dumpster cleaning operation and incinerator, respectively.

Zone 7 includes Site 21 (Berth 16), Site 25 (Classified Materials Incinerator), and Transformers at Building 157 Vault 31 and these sites were investigated collectively as Zone 7 during the Lower Subase RI.

·      The area was investigated during the Pier 33 and Berth 16/Former Incinerator Site Investigation (1995) and the Lower Subase RI (1999). A large area of lead contamination was identified in shallow and deep soil in Zone 7. Petroleum contamination in soil was also evident in two general areas. Little organic contamination was identified in the groundwater; however, two areas of lead contamination were identified in Zone 7 groundwater. The ecological risk assessment for the Thames River adjacent to Zone 7 indicated that risks to ecological receptors were low to moderate, but subsequent dredging made interpretation of the results difficult. The Lower Subase RI Report recommended additional characterization of the sediment and Zone 7 soil and groundwater proceed to an FS for evaluation of appropriate remedial alternatives.

·      Further investigation of the Thames River sediment was completed as part of the 2008 Validation Study. The study showed that the contaminants present in the Zone 7 sediment did not present unacceptable risks to ecological receptors.

·        An FS is currently being prepared for Zone 7 soil and groundwater. It is expected that the FS will be finalized in 2010 and final remedy selection for Zone 7 is expected to be documented in a ROD to be signed in 2011.

·        Current site closeout phase is RI/FS; no site closeout milestones have been reached.

 

 

DDT 1,1,1-trichloro-2,2-bis(4‑chlorphenyl)ethane

DRMO Defense Reutilization and Marketing Office

EE/CA Engineering Evaluation/Cost Analysis

ESD Explanation of Significant Differences

FS Feasibility Study

LNAPL Light Non-Aqueous Phase Liquids

OBDA Overbank Disposal Area

OBDANE Overbank Disposal Area Northeast

OU Operable Unit

PAH Polycyclic Aromatic Hydrocarbon

PCB Polychlorinated Biphenyl

PCE Tetrachloroethene

RACR Remedial Action Completion Report

RI Remedial Investigation

RCRA Resource Conservation and Recovery Act

ROD Record of Decision

NFA No Further Action

NSA New Source Area

SVOC Semi-Volatile Organic Compound

TCE Trichloroethene

USEPA United States Environmental Protection Agency

VC Vinyl Chloride

VOC Volatile Organic Compound

 

 

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