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Site 10 (OU 6)—1927 Disposal Area
The Site 10 1927 Disposal Area and surrounding vicinity is located in the southern portion of the Main Shipyard in an area covered with paved roads, buildings, and parking lots.
The Site 10 Disposal Area was utilized prior to 1927 and until 1941. Wastes disposed of at the site reportedly included various solid wastes generated by NNSY, salvage waste, abrasive blast material (ABM), fly ash, and asbestos waste. There is no design information for the landfill. A Site Screening Process (SSP) investigation for Site 10 was conducted in September 2001. The investigation consisted of installation and sampling of 11 monitoring wells, collection of eight surface soil and 11 subsurface soil samples for laboratory analysis, and visual ID of landfill waste.
The investigation concluded that any minimal habitat for ecological receptors would not be subject to an unacceptable risk, and that the groundwater-to-surface water and/or sediment chemical exposure routes to ecological receptors either: 1) did not exist because there was no CERCLA-type release, or 2) did not present an adverse effect to ecological receptors. The screening human health risk screening, conducted using data collected during the SSP, identified arsenic, iron, and mercury in surface and subsurface soil at the 1927 Disposal Area, and metals in groundwater, as potentially posing unacceptable risks. The SSP report recommended additional investigation at Site 10 to further assess potential soil and groundwater contamination and risk to human health.
In 2004, monitoring well installation and sampling, soil borings, and a round of sampling from existing monitoring wells were conducted at Site 10 to accomplish this objective. The results of this sampling, combined with the SSP sampling, were used in the Site 10 RI, human health risk assessment (HHRA), and focused feasibility study (FFS) process that was completed in June 2006. A Proposed Plan was prepared and made available for public comment from December 9, 2006, through January 9, 2007. No public comments were received during this time period. A public meeting was held on December 20, 2006; however, there were no public participants. The ROD was signed September 2008 selecting land use controls (LUCs) as the remedy. Following signature of the ROD, NAVFAC prepared a remedial design for the LUC measures that will continue at Site 10 to prevent residential development.
CERCLA Status: LUCs have been implemented in accordance with the ROD and the remedial design. Land use remains acceptable under the current industrial use.
Click here for the 2008 ROD.
Site 17 (OU 4)—Building 195 Metal Plating Shop
Building 195 was the main plating shop at NNSY from the early 1970s through the mid-1980s. The ground surface surrounding Building 195 has been completely paved in asphalt. The formerly unpaved area north of Building 195 was used for coal storage from the 1920s until approximately 1966. The site is currently paved, the land use is industrial, and the surficial aquifer is not used as a potable water source.
Previous investigations at Site 17 included soil sampling, monitoring well installation, and groundwater sampling around Building 195. Results from these analyses indicated that metals were present in soil and groundwater. The HHRA was conducted in 1999 to demonstrate that the contaminants at the site do not pose an unacceptable risk to current onsite workers or future construction workers. However, this HHRA did not assess risk to future residential receptors. Because risk to these receptors has not been evaluated, there is an assumed risk to the future residential receptors. With this assumption of risk, institutional controls regarding future land use were recommended in the focused feasibility study to prohibit residential development of the site.
When NNSY announced plans to demolish Building 195, additional sampling was conducted to assess the condition of soils and groundwater under the footprint of the building. Human health risk was reevaluated based on the inclusion of the new data from the additional investigations with the original HHRA data set, and it was confirmed that there are no unacceptable risks to current and future onsite workers and future onsite construction workers. A preliminary evaluation of the future residential exposure scenario indicated there would be unacceptable adverse health hazards for the residential child potentially exposed to surface soil. Additionally, these data supported the conclusion that groundwater at Site 17 presents no unacceptable risk to human health. A revised focused feasibility study was completed in January 2006. The Proposed Plan was completed in 2006, with no public comments received during a public comment period from March 5, 2006, through April 5, 2006. A public meeting was held on March 23, 2006; there were no public participants at the meeting. The ROD for Site 17 was signed in August 2006. Following signature of the ROD, NAVFAC prepared a remedial design for the LUC measures that will continue at Site 17 to prevent residential development.
CERCLA Status: LUCs have been implemented in accordance with the ROD and the remedial design. Land use remains acceptable under the current industrial use. An investigation of per-and polyfluoroalkyl substances (PFAS) is currently underway at Site 17.
Click here for the 2006 ROD.
OU 2 (ER Sites 3, 4, 5, 6, and 7)—Paradise Creek Disposal Area (Soil)
The Paradise Creek Disposal Area lies adjacent to Paradise Creek, south of the Main Shipyard. This OU is composed of five NNSY ER sites and contains:
Site 3, Sanitary Landfill, was the Shipyard’s landfill from 1954 through 1983. The types of waste disposed of at the site included salvage waste, abrasive blast material (ABM), boiler fly and bottom ash, residential trash, and industrial wastewater treatment plant sludge. The Site 3 Landfill consists of the Eastern Landfill and Western Landfill.
Site 4, Chemical Holding Pits, is an area of five chemical waste pits that received waste from 1963 to 1977.
Site 5, Oil Reclamation Area, is an underground storage tank (UST) site where the soils and groundwater have been contaminated by petroleum products related to site releases associated with the USTs, which were removed in 1982.
Site 6, East Dump, was used for disposal of solvents when the Site 4 pits were full. The area was used from the mid-1960s to 1977.
Site 7, Bermed Chemical Pits, was used from the late 1950s through the 1970s. The type and quantity of waste disposed here are unknown. However, during a test pit investigation conducted in 2003, a significant amount of calcium hydroxide was observed. Most of the calcium hydroxide formed a berm along the perimeter of the site. Site 7 was excavated and restored as a tidal wetland with an NTCRA that was completed in 2006.
The previous investigations indicated the presence of elevated metals, polycyclic aromatic hydrocarbons (PAHs), phenols, and polychlorinated biphenyls (PCBs) in surface soils. The fill material and subsurface soil contained volatile organic compounds (VOCs), PAHs, PCBs, and metals. The water table aquifer within and downgradient of the site contained several VOCs, semivolatile organic compounds (SVOCs), and metals. Groundwater is addressed separately as OU7.
To address potential ecological concerns associated with the adjacent marsh sediments, an Ecological Risk Assessment (ERA) for Paradise Creek in association with the Navy Sites was completed and remediation goals were established for Navy Sites' marsh sediments. The results of the ERA identified an area of sediment along Paradise Creek adjacent to OU2 that contained contaminants above the levels of established cleanup goals.
Following completion of the ERA and to address soil and sediment contamination, a design was completed to support a non-time-critical removal action (NTCRA) at OU2. The design established a clean soil cover over the landfill, stabilized the potentially unstable side slopes of the landfill, and provided stormwater drainage features. The design was completed in four phases to accommodate construction sequencing:
Phase I – Site Preparation and Site 7
Phase II – Eastern Landfill Area
Phase III – Western Landfill Area
Phase IV – Marsh Sediment Remediation Area
Phase I construction activities were initiated in late FY 2005 and completed in December 2006. Site 7 was excavated and converted to a tidal wetland along Paradise Creek. The remainder of the construction phases were not initiated until 2009 to prepare additional CERCLA documentation.
The Proposed Plan, presenting the preferred alternative, was made available for public review and comment from March 16, 2009, through May 1, 2009. A public meeting was held on March 31, 2009, there were no comments received during the public comment period and there were no attendees at the public meeting. The draft Record of Decision (ROD) outlining the selected remedy for soil (soil cover with institutional controls) was submitted in May 2009 and signed as Final in May 2010. Additionally, the NFA determination for Site 7 was included in the Proposed Plan and ROD. The marsh sediment area “Phase IV – Marsh Sediment Remediation Area” was included in the Proposed Plan; however, based upon comments received from USEPA counsel during review of the OU2 ROD, the sediment component was removed prior to the document being finalized. Following completion of the OU2 ROD, Phase II, III, and IV construction activities were completed between May 2009 and September 2010.
The “Phase IV” sediment removal was conducted on approximately 0.3 acres of marsh sediments south of the Site 3 Eastern Landfill along Paradise Creek. Construction activities consisted of excavation of the sediments with restoration as tidal salt marsh. Current status of the Paradise Creek sediments can be found in the Site Management Plan.
CERCLA Status: LUCs have been implemented in accordance with the ROD and the remedial design. Access is restricted by fence and locked; the site is periodically maintained and mowed as a “closed” landfill.
Click here for the 2010 ROD addressing OU2.
OU 7 (ER Sites 3, 4, 5, 6, and 7)—Paradise Creek Disposal Area Groundwater
OU 7 was initially investigated under OU 2. Because the groundwater data for OU2 were approximately 10 years old when the NTCRA was being planned, additional data were needed to support a future groundwater remedy. The PMT agreed to address soil and groundwater separately in 2008 so that the soil remedy would not be delayed.
Investigations were conducted in 2007, 2008, 2011, and 2017 to refine the nature and extent of constituents in groundwater, evaluate the groundwater-to-surface water pathway, refine the understanding of light nonaqueous phase liquid (LNAPL) and DNAPL present at the site, and assess potential for emerging chemicals of environmental concern (1,4-dioxane, dioxins and furans, and PFAS).
CERCLA Status: OU 7 is currently in the Remedial Investigation Phase. Additional information can be found in the Site Management Plan.
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