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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.
Site 15, Past Pier Side Maintenance Operations, underwent a desktop review in FY 2004, and the NNSY partnering team concluded that the site was a site screening area that warranted further review and evaluation in the site screening process, based on NNSY pier-side activities adjacent to the Southern Branch of the Elizabeth River. A desktop review and historical records search was conducted in mid-FY 2006, and a Preliminary Assessment and Action Determination for Site 15 – Past Pier-Side Maintenance Operations was prepared. A no further action determination was made for the site in December 2006 by the partnering team, based in part on the following findings: a specific source caused from a CERCLA release at the site cannot be defined, most of the potentially affected sediment has been removed by maintenance dredging, planned waterfront improvements in the area will encapsulate any remaining affected sediment, and engineering controls to prevent future releases have been implemented at the site.
USEPA sent a formal letter requesting sediment sampling along the NNSY and Southgate Annex waterfront area in December 2010. This request was escalated to Virginia-Tier III in March 2011; the NNSY partnering team was advised by Virginia-Tier III to make plans to conduct a near-shore sediment evaluation. Planning for this investigation is underway as of August 2015.
CERCLA Status: The near-shore sediment sampling activities are planned to be initiated in late FY 2015 (work planning). Investigation/sampling efforts are anticipated to be completed in FY 2016 and 2017.
Next Steps: Following completion of the near-shore sediment sampling.
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.
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. Sediments associated with the site had not been investigated.
A Draft Feasibility Study was prepared for OU2 in October 2000. The remedial alternative recommended in this report was Alternative 4 – Soil Cover with Institutional Controls. To address potential ecological concerns associated with the adjacent marsh sediments, an Ecolological Risk Assessment (ERA) for Paradise Creek in association with the Navy Sites was completed and remediation goals were established for Navy Sites' marsh sediments. As a result of the additional ecological investigation for the ERA and reporting to be completed, the draft feasibility study was never finalized.
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, an Engineering Evaluation/Cost Analysis (EE/CA) for a non-time critical removal action (NTCRA) was completed in April 2004 to develop response action alternatives to mitigate exposure to the Site 3 eastern and western landfill, Site 7 Bermed Chemical Pits, and near-shore Paradise Creek marsh sediments to account for unacceptable exposure to humans and ecological receptors. The EE/CA was made available for public review and comment between March 10, 2004, and April 10, 2004. No comments were received from the public during the public comment period. The NTCRA was planned for OU2 based on the EE/CA.
A design was completed to support the NTCRA at OU2 for a landfill soil cover and side slope stabilization in 2004. The design established a clean soil cover over the landfill, stabilized the potentially unstable side slopes of the landfill, and provided stormwater drainage features. Various alternatives were applied for stabilizing each side slope of the landfill (depending on existing conditions), including covering, re-grading, and installing riprap. Unless engineering measures were provided to increase the long-term slope stability, the general approach for side slope stabilization was to add fill to extend the toe of the slope outward and establish a 3H:1V slope. In 2005, pre-removal confirmatory sampling was conducted in the marsh sediments adjacent to the western landfill to define the boundary for the RA. The results of this sampling were incorporated into the Phase IV design.
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 as outlined in the following paragraphs.
In 2007, a Feasibility Study for OU2 was initiated, based on the draft version that had been prepared in 2000 and in consideration of the design documents completed for the NTCRA. Because the groundwater data for OU2 were approximately 10 years old, additional data were needed to support a future groundwater remedy. As a result, the groundwater component of OU2 was removed and addressed separately (USEPA CERCLIS ID for Paradise Creek Disposal Area Groundwater is OU7).
In 2008, the partnering team agreed to address soil and groundwater separately. The Focused Feasibility Study for soil was finalized in March 2009. The recommended alternatives for soil and sediment included construction activities associated with Phases II, III, and IV fromthe EE/CA. 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. A current task for the partnering team is to review the previous reports and documentation for the sediment removal that has occurred at OU2 in order to determine the path forward to closure of the sediments under a ROD.
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.
OU 7 was initially investigated under OU 2. The NNSY partnering team decided to separate it from OU 2 in 2007 because of schedule implications.
The Baseline Human Health Risk Assessment (HHRA) conducted during the 2002 Phase II Remedial Investigation (RI) indicated potential unacceptable risk was present due to exposure of shallow and deep groundwater at the site.
A dense non-aqueous phase liquid (DNAPL) investigation completed in 2001 consisted of a geophysical survey, free product measurements at existing site wells, groundwater level gauging, direct-push technology soil and groundwater sample collection, test pitting and monitoring well installation, and cone penetrometer testing. The conclusions of the DNAPL investigation indicated chlorinated VOCs and benzene, toluene, ethylbenzene, and xylene (BTEX) constituents were detected in generally the same areas in the shallow Columbia aquifer; however, chlorinated solvent contamination was detected at high concentrations over a broader area than BTEX constituents. The soil borings installed in the lower portion of the Columbia aquifer exhibited low levels of VOCs and SVOCs. No specific evidence of DNAPL contamination was identified in the soil borings installed in the lower portion of the Columbia aquifer; however, the conclusions of the report documented DNAPL was removed from one recovery well that is no longer present at the site during the Oil Reclamation Area system construction. Recommendations of the DNAPL investigation consisted of periodic extraction of DNAPL from RW11.
Supplemental groundwater investigations were conducted in 2007 and 2008 and included a water level survey, free product survey, and groundwater sampling. This information was intended to provide an updated set of groundwater data to compare to the RI data that had been collected in the middle to late 1990s. Groundwater gauging confirmed general groundwater flow directions consistent with previous investigations. The results of the product gauging indicated that the product does not appear to be migrating over time (based on comparison with the 1998 free product delineation). The results of the groundwater sampling event indicated volatile organic compounds (VOCs), one semivolatile organic compound (SVOC), and metals exceeded their established maximum contaminant level (MCL) or action level in at least one monitoring location in shallow groundwater. Chlorinated VOCs were generally detected in the central portion of the western landfill, in the vicinity of where they were detected in soil during the DNAPL survey. A total of one VOC (vinyl chloride) and two metals (arsenic and lead) exceeded their established MCL or action level in deep groundwater of the Yorktown aquifer at three monitoring wells. The chlorinated VOC exceedance in the Yorktown aquifer was within the Site 6 area, downgradient of the VOCs encountered during the DNAPL study.
The 2011 additional groundwater investigation consisted of a water level survey, monitoring well installation, free product survey and investigation, groundwater sampling, and subsurface soil sampling (based upon the results of the 2001 DNAPL study) in order to evaluate alternatives for the Feasibility Study for OU7. The purpose of the investigation was to identify potential source areas and further characterize the groundwater contamination. A Laser-Induced Florescence investigation was also conducted to determine the extent of free product in the subsurface.
The 2011 groundwater data were also screened against Biological Technical Assistance Group (BTAG) surface water screening values to assess the potential ecological risk exposure pathways for aquatic biota at the groundwater-to-surface-water interface (GSI). Site-specific modeling was completed to estimate concentrations of constituents of potential concern and the potential for ecological risk both in the GSI and in the main body of Paradise Creek. Based on the results, the NNSY partnering team decided to place the groundwater Feasibility Study on hold pending a phased investigation of the pore water in order to evaluate the GSI pathway.
A Sampling and Analysis Plan (SAP) and the field work associated with additional groundwater sampling and the second phase of pore water sampling are planned for the site in FY 2016. The groundwater sampling is intended to provide an updated data set for select monitoring wells as well as determine if emerging contaminants (specifically 1,4-dioxane and dioxins/furans) are present at the site. Three sediment samples from within Paradise Creek adjacent to the eastern landfill will also be collected. The results of the groundwater, pore water, and sediment sampling will be documented in a Supplemental RI report for OU7. The Supplemental RI will also include an updated/current HHRA based upon the new groundwater data set and an evaluation of the potential for ecological risk to receptors in the GSI pathway.
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