final record of decision operable unit 1, site 2, scott ... · norfolk naval shipyard (nnsy)...

F i n a l

Record of Decision Operable Unit 1, Site 2,

Scott Center Landfill Norfolk Naval Shipyard

Portsmouth, Virginia

Department of the Navy Naval Facilities Engineering Command

Mid Atlantic

SEPTEMBER 2005

Contents

Acronyms and Abbreviations ..........................................................................................................v 1 Declaration..............................................................................................................................1-1

1.1 Site Name and Location .....................................................................................1-1 1.2 Statement of Basis and Purpose ........................................................................1-1 1.3 Description of the Selected Remedy.................................................................1-1 1.4 Statutory Determinations...................................................................................1-2 1.5 Authorizing Signatures ......................................................................................1-2

2 Decision Summary ................................................................................................................2-1 2.1 Site Name, Location, and Background.............................................................2-1 2.2 Investigation History ..........................................................................................2-1 2.3 Community Participation ..................................................................................2-5 2.4 Scope and Role of Response Actions................................................................2-6 2.5 Site Characteristics ..............................................................................................2-7 2.6 Current and Potential Future Site and Resource Uses...................................2-7 2.7 Site Risks...............................................................................................................2-8

2.7.1 Soil and Marsh Sediment ......................................................................2-8 2.7.2 Shallow and Deep Groundwater .........................................................2-8 2.7.3 Surface Water..........................................................................................2-9

2.8 No Further Action Necessary............................................................................2-9 2.9 Documentation of Significant Changes............................................................2-9

3 Responsiveness Summary ...................................................................................................3-1 4 References ...............................................................................................................................4-1

Figures

2-1 Location of Norfolk Naval Shipyard 2-2 Location of Scott Center Landfill and Adjacent Marsh Sediment 2-3 Conceptual Site Model – Human Health Risk Assessment 2-4 Conceptual Site Model – Ecological Risk Assessment 2-5 Confirmation Sample Grid 2-6 OU1 Site 2 – Tidal Wetlands Site Restoration

III

Acronyms and Abbreviations

CERCLA Comprehensive Environmental Response, Compensation and Liability Act

COPC constituent of potential concern

CSM conceptual site model

CNI Chief of Naval Installations

CNRMA Commander, Navy Region Mid-Atlantic

EE/CA Engineering Evaluation/Cost Analysis

EPA United States Environmental Protection Agency

ERA Ecological Risk Assessment

FFA Federal Facilities Agreement

FS Feasibility Study

ft foot, feet

HHRA Human Health Risk Assessment

IAS Initial Assessment Study

IRP Installation Restoration Program

LUC land use control

NCP National Oil and Hazardous Substances Pollution Contingency Plan

NFA no further action

NNSY Norfolk Naval Shipyard

NPL National Priorities List

NTCRA non-time-critical removal action

OU Operable Unit

PRAP Proposed Remedial Action Plan

RAB Restoration Advisory Board

RACG remedial action clean up goal

RAO remedial action objective

RCRA Resource Conservation and Recovery Act

V

RECORD OF DECISION SITE 2: OPERABLE UNIT 1

RFA RCRA Facility Assessment

RG remediation goal

RI Remedial Investigation

ROD Record of Decision

SARA Superfund Amendments and Reauthorization Act

SMP Site Management Plan

SWMU Solid Waste Management Unit

TAL Target Analyte List

TCL Target Compound List

VDEQ Virginia Department of Environmental Quality

VI

SECTION 1

Declaration

1.1

1.2

1.3

Site Name and Location Operable Unit 1, Site 2, Scott Center Landfill Norfolk Naval Shipyard (NNSY) Portsmouth, Virginia

The Scott Center Annex was a property asset of NNSY (EPA ID# VA1170024813) when NNSY was placed on the United States Environmental Protection Agency (EPA’s) National Priorities List (NPL) in July 1999. With the creation of the Navy’s Chief of Naval Installations (CNI) and regionalization of Navy property assets, the Scott Center Annex became cognizant of the Commander, Navy Region Mid-Atlantic (CNRMA), and was assigned a new regulatory identifier (EPA ID # VAR000504928) in February 2003.

Statement of Basis and Purpose This Record of Decision (ROD) presents the selected remedy at Operable Unit (OU) 1, Site 2, Scott Center Landfill, at NNSY. The determination has been made in accordance with the Comprehensive Environmental Response, Compensation and Liability Act of 1980 (CERCLA), as amended by the Superfund Amendments and Reauthorization Act of 1986 (SARA), and to the extent practicable, the National Oil and Hazardous Substances Pollution Contingency Plan (NCP). This decision is based on information contained in the Administrative Record file for the site.

The United States Department of the Navy (Navy) is the lead agency and provides funding for site cleanups at NNSY. The Navy and EPA Region III issue this ROD jointly. The Virginia Department of Environmental Quality (VDEQ) concurs with the selected remedy.

Description of the Selected Remedy OU1, Site 2, Scott Center Landfill is one of several Installation Restoration Program (IRP) sites under CERCLA at NNSY. Information about the other IRP sites at NNSY can be found in the current version of the Site Management Plan (SMP), which is located in the Administrative Record.

The selected remedy for OU1, Site 2, Scott Center Landfill is no further action (NFA). A removal action was conducted at Site 2 from October 2004 through April 2005, which eliminated potentially unacceptable risk associated with waste and waste-impacted areas at the site. The remaining site soil and sediment concentrations meet the site-specific cleanup goals that were established for the removal. The Navy may authorize monitoring to verify that no unacceptable exposures to contaminants at the site occur in the future.

1-1

RECORD OF DECISION SITE 2: WASTE DISPOSAL AREA

The removal action conducted at aUI, Site 2, Scott Center Landfill has eliminated the needto conduct further remedial action. As there are no hazardous substances, pollutants, orcontaminants remaining onsite above levels that allow for unlimited use and unrestrictedexposure, a 5-year review will not be required.

I~te CJ c.,~O () 5

to L ~/J OJ-DateAB~~-

Hazardous Site Cleanup DivisionEP A (Region III)

1-2

SECTION 2

Decision Summary

2.1

2.2

Site Name, Location, and Background The NNSY facility is located in Portsmouth, Virginia, on the Southern Branch Elizabeth River, approximately 15 miles from the mouth of the Chesapeake Bay (Figure 2-1). NNSY has been continuously operated since 1767 and is currently used exclusively for ship repair and overhaul. The present Shipyard and the nearby Navy-owned noncontiguous areas include: the Main Shipyard, Southgate Annex, Scott Center Annex, New Gosport, and Paradise Creek Disposal Area. NNSY was placed on the NPL in July 1999.

OU1, Site 2, the Scott Center Landfill is located on the southern boundary of the Scott Center Annex (Figure 2-2). Site 2 was used intermittently during the late 1950s for disposal of wastes generated from drydock operations. According to historic documents, wastes discarded in the landfill included sand and abrasive blast grit with paint residues, sanitary wastes, and other “industrial wastes,” which were not specifically defined. The majority of the material placed at Site 2 was hydraulic fill, a material consisting of fine sand, silt, clay, and water generated from maintenance of the nearby waterways by dredging. The volume of waste and waste-impacted soils at Site 2 was calculated to be approximately 10,400 cubic yards (CH2M HILL, 2003c).

Investigation History The following subsections provide summaries of the investigations that have been conducted at Site 2. No enforcement activities have occurred at NNSY.

Initial Assessment Study (Water and Air Research, Inc., 1983) An Initial Assessment Study (IAS) report was prepared to identify potential areas of concern at NNSY through a review of waste generation, handling, and disposal practices. The review involved historical records, aerial photographs, site visits/inspections, and interviews with NNSY personnel. The IAS identified Site 2 as an area that warranted further investigation to assess residual contamination and potential for contamination of nearby surface waters.

RCRA Facility Assessment (NUS Corporation, 1986 and A.T. Kearney, Inc., 1987) A Resource Conservation and Recovery Act (RCRA) Facility Assessment (RFA) report was prepared to identify Solid Waste Management Units (SWMUs) and other areas of concern at NNSY and evaluate their potential for past releases of hazardous wastes or hazardous constituents to the environment. The assessment included review of NNSY, state, and EPA records; review of historical aerial photographs; interviews with NNSY personnel; and site visits. Site 2 was identified as an SWMU in the RFA report, which recommended analysis of groundwater and surface water to identify any possible release.

2-1


Interim Remedial Investigation (Interim RI) (IT Corporation, 1989) An Interim Remedial Investigation (RI) was conducted to follow up on the recommendations of the IAS and RFA by conducting sampling of the groundwater, soil, sediment, and surface water at several NNSY sites, including Site 2. The Interim RI indicated that further investigation of Site 2 was warranted.

Phase I Remedial Investigation and Feasibility Study (RI/FS) (Foster Wheeler Environmental Services, 1995) A Phase I RI and Feasibility Study (FS) was conducted to further investigate several sites, including Site 2, discussed in the Interim RI. Field activities were conducted to characterize the nature and extent of contamination and potential human health risks. Based on concentrations of chemicals present in various media, additional characterization was recommended to properly delineate areas of concern and identify a site remedy.

Draft Phase II Remedial Investigation and Feasibility Study (CH2M HILL, 1999) Based on the preliminary conclusions of the draft Human Health Risk Assessment (HHRA) in the draft Phase II RI, remedial action alternatives were developed in the draft FS for the landfill. A soil and asphalt cap with land use controls (LUCs) was identified as the preferred alternative. However, completion of the RI/FS was deferred pending assessment of potential ecological concerns in Paradise Creek, which runs adjacent to Site 2. Subsequent to the completion of the 2001 Ecological Risk Assessment (ERA) for Paradise Creek and the RI and HHRA for Site 2, the Navy determined complete excavation of waste and contaminated marsh sediment was the most feasible and permanent remedy for Site 2. Consequently, an Engineering Evaluation/Cost Analysis (EE/CA) for a non-time-critical removal action (NTCRA) was prepared in lieu of finalizing the FS for Site 2.

Final Phase II Remedial Investigation and Human Health Risk Assessment (CH2M HILL, 2001a) The RI, including the HHRA, was completed to define the nature and extent of soil and groundwater contamination, to assess potential current and future threats to human health, and to evaluate potential ecological risks related to Site 2. Based on the sampling activities, the surface soil, fill material, and subsurface soil contained elevated metals, polycyclic aromatic hydrocarbons, and polychlorinated biphenyls above background concentrations. The shallow groundwater (Columbia Aquifer) contained several metals (antimony, arsenic, nickel, zinc, and iron) at concentrations higher than upgradient sample concentrations, indicating potential impacts from the landfill. Concentrations of these constituents in the deep groundwater (Yorktown Aquifer) were lower than the shallow groundwater, and not higher than upgradient concentrations, indicating that the deep groundwater has not been impacted by the landfill.

The primary fate and contaminant migration pathways at Site 2 were determined to be surface runoff and erosion of soil to the adjacent marsh, infiltration and leaching of precipitation through the soil to the groundwater system, and groundwater discharge to the adjacent marsh. Based on the primary fate and migration pathways, the conceptual site models (CSMs) for human health (Figure 2-3) and ecological (Figure 2-4) exposure pathways were developed to evaluate site risks in the HHRA and ERA, respectively.

2-2

2—DECISION SUMMARY

The HHRA characterized potential current and future risks to human health; risks were calculated for the current onsite construction worker and potential future land use exposures for recreational users, onsite construction workers, and onsite residents. Potential risks to human health in the soil (surface and subsurface soil combined) at Site 2 were identified as arsenic, iron, and manganese. Manganese was also identified as presenting a potential human health risk in deep groundwater; however, the risk is the result of naturally occurring concentrations because the RI found that the deep groundwater had not been impacted by the Site 2 landfill. Metals were the principal contributors to human health risk from exposure to shallow groundwater.

The RI and HHRA recommended a focused FS for the Site 2 landfill area to mitigate risks from contact to landfill contents, soil, and groundwater. The RI also noted that the potential human health risks from exposure to surface water and sediment at Paradise Creek, adjacent to Site 2, would be evaluated separately.

Ecological Risk Assessment, Paradise Creek (CH2M HILL, 2001b) An ERA was conducted for Paradise Creek to identify Navy sources potentially contributing to ecological risk in the creek and its adjacent marsh habitats. The primary focus of the ERA was the potential release of contaminants to surface water and sediments from Site 2 and other Navy sites on Paradise Creek (IRP Sites 3 through 7). Some potential for adverse effects to benthic-dwelling organisms (e.g., clams, mussels) from direct exposure to metals and pesticides in sediment was identified at isolated locations adjacent to Site 2. The ERA results noted that there was not a potential risk to higher trophic-level receptors (birds and mammals) from site-related chemicals in sediment and there was minimal potential risk to aquatic life from site-related chemicals in surface water.

Paradise Creek HHRA [Phase II Remedial Investigation Report Operable Unit 2 Paradise Creek Disposal Area (CH2M HILL, 2002)] Following the completion of the ERA for Paradise Creek, an HHRA was completed using data regarding surface water, sediment, and biota tissue (clams and mussels) from the lower reaches of Paradise Creek, adjacent to OU1 (Site 2, Scott Center Landfill) and OU2 (Paradise Creek Disposal Area). The HHRA for Paradise Creek surface water and sediment is summarized in detail in the RI for OU2. It evaluated potential risks to adult and child recreational users from incidental ingestion and dermal contact with surface water and sediment and to adult and child fishermen from ingestion of clams and mussels. The Paradise Creek HHRA concluded that there are no unacceptable human health risks associated with current or future recreational exposure to Paradise Creek surface water or sediment. The Paradise Creek HHRA did identify a slight potential risk associated with consumption of clams and mussels due to elevated arsenic and iron in biota samples. However, the concentrations of these inorganics, upon which this slight risk was based, were below the corresponding background upper tolerance limits developed for Paradise Creek (CH2M HILL, 2003a). Additionally, due to widespread contamination of sediment in the Southern Branch Elizabeth River and its tributaries (including Paradise Creek), the Virginia Department of Health had prohibited taking shellfish from this area for any purpose (Virginia Department of Health, 1997).

2-3


Development of Site-Specific Remediation Goals for Marsh Sediments in Paradise Creek (CH2M HILL, 2003a) Site-specific remediation goals (RGs) for Paradise Creek marsh sediments at Site 2 were developed. RGs are risk-based concentrations that represent approximate chemical-specific remediation targets for constituents of potential concern (COPCs) within a given exposure pathway as identified in the ERA. The RGs do not necessarily serve as a specific cleanup level because naturally occurring background concentrations may exceed these risk-based criteria. Rather, an RG represents an environmental concentration that may serve as a threshold concentration for biological effects and a starting point for developing a remedy to reduce chemical levels.

Evaluation of Paradise Creek Marsh Sediments (CH2M HILL, 2003b and 2004a) An evaluation of Paradise Creek marsh sediments adjacent to Scott Center Landfill was conducted to identify a limited set of COPCs as potential cleanup target compounds and to delineate the marsh sediment contamination related to a CERCLA release from Site 2. Additional background data were also collected to statistically strengthen the data set to establish the ambient or anthropogenic marsh sediment contaminant levels in Paradise Creek. Based on the statistical analysis of the data collected from this investigation, cobalt, barium, and copper were found to be indicators for all COPCs in the near-shore marsh sediments adjacent to the Scott Center Landfill. Site-specific remedial action clean-up goals (RACGs) for the planned removal action were calculated to the greater value of either the RG or the background concentration for each COPC.

Waste Delineation (CH2M HILL, 2003c) A waste delineation was conducted at Site 2 to provide additional information regarding the extent and characterization of the landfill contents and assess potential removal action alternatives. The volume of buried waste calculated to be present at Site 2 was approximately 6,000 cubic yards. The total volume of waste and waste-impacted soils was calculated to be approximately 10,400 cubic yards. Test results indicated that the waste-impacted soils were non-hazardous for disposal purposes.

Engineering Evaluation/Cost Analysis and Action Memorandum (CH2M HILL, 2004b) Based on the findings of the previous investigations, an EE/CA was conducted to identify and evaluate remedies or removal actions to mitigate potential risk at Site 2. Three alternatives were identified, evaluated, and ranked. Based on the comparative analyses of the removal alternatives, the selected NTCRA involved excavation of landfill materials and construction of tidal wetlands for the landfill area, direct excavation and backfill of the adjacent marsh sediment, and construction of enhanced tidal wetlands.

As required by 40 CFR Section 300.415(n)(4), a public notice of availability of the Draft EE/CA was published in The Virginian-Pilot on January 18, 2004 and was made available to the public for comment from January 27 to February 27, 2004. A public information session was held on February 24, 2004. No comments were received from the public during the comment period. The Navy signed an Action Memorandum (CH2M HILL, 2004c) on July 1, 2004 to implement the NTCRA as specified in the EE/CA.

2-4


Pre-Removal Confirmatory Sampling of Marsh Sediment (CH2M HILL, 2004a) Marsh sediment samples adjacent to Site 2 were collected from the marsh adjacent to Site 2 and Paradise Creek and analyzed for the metal COPCs to measure the volume of marsh sediment potentially impacted by the Scott Center Landfill. The resulting area identified for removal by comparing the COPC concentrations to the RACGs was approximately 0.4 acre.

Removal Action (ECOR Solutions, 2004 and 2005) The NTCRA activities at Site 2 were conducted from October 2004 through April 2005. The NTCRA was completed in accordance with removal design (CH2M HILL, 2004d) and the contractor project implementation plans (ECOR Solutions, 2004). Approximately 28,775 tons of waste, soil, and marsh sediment were removed (Figures 2-2 and 2-5). The limits of marsh sediment excavation were delineated based on pre-removal confirmatory sampling. To ensure successful mitigation of risk, the ecologically based marsh sediment RACGs established for metal COPCs were applied to confirmation samples collected from the bottom of the landfill excavation so the landfill area could be constructed as a tidal wetland after waste removal. The NTCRA completion report (ECOR Solutions, 2005) summarizes the confirmation sample results from the NTCRA and demonstrates that the potential risk to human and ecological receptors posed by Site 2 has been mitigated. Figure 2-6 depicts the site conditions following completion of the removal action.

2.3 Community Participation The Navy and EPA provide information regarding the cleanup of NNSY to the public through the community relations program, which includes a Restoration Advisory Board (RAB), public meetings, the Administrative Record file for the site, the information repository, and announcements published in local newspapers.

In accordance with Sections 113(k) and 117(a) of CERCLA, the Navy provided a public comment period from July 27 through August 27, 2005, for the Proposed Remedial Action Plan (PRAP) for Site 2. A public meeting to present the PRAP was held on August 8, 2005, at the Portsmouth Main Branch Public Library. Public notice of the meeting and availability of the document was published in The Virginian-Pilot newspaper on July 27, 2005.

The PRAP and previous investigation reports for Site 2 are available to the public in the Administrative Record maintained at:

Naval Facilities Engineering Command, Atlantic 6508 Hampton Blvd. Norfolk, Virginia 23508

Or, the information repository located at:

Portsmouth Main Branch Public Library 601 Court Street Portsmouth, Virginia 23704 (757) 393-8501

2-5


2.4 Scope and Role of Response Actions NNSY was placed on EPA’s NPL in July 1999. As a result of the NPL listing and pursuant to CERCLA, the Navy, EPA, and VDEQ entered into a Federal Facilities Agreement (FFA) to ensure that the environmental impacts associated with past and present activities at NNSY are thoroughly investigated and appropriate remedial action is taken as necessary to protect the public health, welfare, and the environment and to establish a procedural framework and schedule for developing, implementing, and monitoring appropriate response actions at NNSY in accordance with CERCLA, as amended, and the NCP. The NNSY FFA identifies and categorizes every area of the shipyard that has been identified as having, or is suspected to have had, a release of a hazardous substance. The following three OUs, comprised of seven individual IRP sites, are being investigated following the CERCLA process, with ultimate closure performed pursuant to an ROD:

• OU 1 (IR Site 2: the Scott Center Landfill) • OU 2 (IR Sites 3 through 7: the Paradise Creek Disposal Area), which will be

investigated and remediated as one OU because these five individual IR sites are close to one another.

o IR Site 3: the Sanitary Landfill o IR Site 4: the Chemical Holding Pits o IR Site 5: the Oil Reclamation Area o IR Site 6: the East Dump o IR Site 7: the Bermed Chemical Pits

• OU 4 (IR Site 17: Building 195) Two OUs have been resolved by removal actions:

• OU 3 (IR Site 9: the former Acetylene Waste Lagoon) was remediated by an NTCRA undertaken from December 2002 through November 2003.

• OU 5 (Site 1: the former New Gosport Landfill) was remediated by an NTCRA undertaken from August 2000 through June 2001.

In addition, the NNSY FFA identifies two Site Screening Areas for further investigation under the site screening process:

• IR Site 10: 1927 Landfill • IR Site 15 Past Pier-Side Industrial Operations The NNSY FFA also includes a list of 154 sites for which no further action under CERCLA is required. Based upon the complete removal of waste, contaminated soil, site-related impacted marsh sediment, and groundwater, no principal threats are posed by Site 2 and NFA is the preferred alternative. This ROD for Site 2 does not include or directly impact any other sites at NNSY.

2-6


2.5

2.6

Site Characteristics Although Site 2 encompasses 7 acres, the landfill area (limits of waste disposal) covers only 1.7 acres; the remaining 5.3 acres consist of a marshy, tidal floodplain that extends to Paradise Creek (Figure 2-2). Of the 5.3 acres of marshland, only a 0.4-acre adjacent section has been potentially impacted by the landfill. There are no surface or subsurface features (e.g., tanks, structures) or areas of archaeological or historical importance at Site 2. Site 2 is relatively flat, with topography ranging between 7 to 9 feet (ft) above mean sea level with a gentle slope to the southwest and southeast toward Paradise Creek.

Site investigations previous to the NTCRA indicated buried waste at the site was an average of 5 ft thick, overlain with an average of 2 ft of topsoil. The landfill boundaries were easily distinguishable to the east, west, and south because the fill area was approximately 5 to 7 ft higher than the surrounding marsh and was covered with a well-maintained stand of grass. The northern boundary of the landfill was identified in a waste delineation study to extend approximately 10 ft beyond the fenced border of the landfill up to, but not extending under, the asphalt road (Figure 2-2)(CH2M HILL, 2003c).

The shallow groundwater (Columbia Aquifer) at Site 2, prior to the NTCRA, existed primarily in hydraulic fill and native sands and silts. Shallow groundwater at the site ranged between 4 and 8 ft below ground surface and flowed toward and discharged to the south and southwest to Paradise Creek, with a low hydraulic gradient (0.01 ft/ft). The Columbia Aquifer within the site was removed during the NTCRA to the Yorktown Confining Unit. This Yorktown Confining Unit is comprised of fine sand, silt, and clay that is 10 to 20 ft in thickness and separates the overlying Columbia Aquifer from the sand and silty sand of the underlying deep groundwater (Yorktown Aquifer). Due to the presence of the clay-confining unit, the deep groundwater was not impacted by Site 2 activities.

To mitigate the potential human health and ecological risks identified in the RI, HHRA and ERA, waste, soil, marsh sediment, and the underlying Columbia Aquifer were removed from Site 2 as a NTCRA during 2004 through 2005 and replaced with clean fill and tidal wetlands.

Current and Potential Future Site and Resource Uses Site 2 is currently not being used by the facility. The former landfill is bounded by the Scott Center Annex, consisting of personnel quarters and recreational ball fields to the north, and the tidally influenced Paradise Creek to the south (Figure 2-2). Access to Site 2 from the Scott Center Annex is controlled by an 8-ft-high chain link fence and a locked gate. Upstream and downstream of Scott Center Annex and Site 2 along Paradise Creek are residential, commercial, and light industrial properties.

There is currently no planned future land use at Site 2. Future residential development of the site is unlikely; however, residential scenarios were evaluated in the HHRA to be conservative.

Groundwater from beneath or downgradient of Site 2 is not currently used. The VDEQ considers the future beneficial use of the groundwater as being a potential potable source; however, the removal action at the site resulted in the complete removal of the waste and

2-7


shallow aquifer, extending to a depth where the natural blue-green clay characteristic of the Yorktown Confining Unit underlying the site was encountered. Site restoration following the removal action included backfilling the excavated areas to design elevations to support a tidal salt marsh. Since the NTCRA, the groundwater flow of the non-impacted Columbia Aquifer upgradient of Site 2 has re-established itself to discharge to these created wetlands. As such, the actions taken at Site 2 have eliminated the potential potable use of the Columbia Aquifer that was impacted by the site. Private deep wells (Yorktown Aquifer) that are permitted for irrigation only exist locally, upgradient of NNSY, within the cities of Chesapeake and Portsmouth. The City of Portsmouth supplies water to NNSY and surrounding communities using a combination of surface water and deep groundwater (Upper/Middle or Middle Potomac Aquifers) supplies. There is also a permitted municipal deep groundwater well located approximately 10 miles to the east/southeast of NNSY at the Chesapeake Civic Center. Because a tidal wetland was constructed over Site 2 and Paradise Creek is located directly downgradient, any current or future use of shallow or deep groundwater is or will be hydraulically upgradient from the former landfill.

2.7 Site Risks A detailed discussion of risk identified at Site 2 prior to the NTCRA can be found in the Phase II RI and HHRA (CH2M HILL, 2001a), the ERA for Paradise Creek (CH2M HILL, 2001b), and the HHRA for lower Paradise Creek (CH2M HILL, 2002). In summary, prior to any interim actions at the site, potential human health risks were associated with exposure to groundwater, soil, landfill contents, and ingestion of Paradise Creek clams and mussels. For ecological receptors, potential adverse effects were identified for benthic-dwelling organisms from direct exposure to metals and pesticides in sediment. Site-specific RACGs were developed for the NTCRA, and confirmation samples were collected to verify the completion of interim removal actions. By the NTCRA, all risks attributable to Site 2 have been mitigated. The NTCRA completion report documents that the removal action activities were successful in removing waste and waste-impacted areas and the remaining site soil and sediment concentrations meet the site-specific RACGs that were established for the NTCRA (ECOR Solutions, 2005).

2.7.1 Soil and Marsh Sediment The potential human and ecological risks posed by Site 2 waste, soil, and marsh sediment have been mitigated by the NTCRA, and no further remedial action is necessary to ensure protection of human health and the environment. A total of 30 confirmation samples were collected prior to the excavation to characterize the concentrations of COPCs remaining in place for comparison to the RACGs. Figure 2-2 illustrates the extent of the removal action. The results of confirmation samples and demonstration that the RACGs have been met are provided in Figure 2-5.

2.7.2 Shallow and Deep Groundwater Potential human health risks were identified based on future use of shallow and deep groundwater. Excavation for waste removal extended 8 to 10 ft below ground surface, through the Columbia Aquifer, to the natural blue-green clay characteristic of the Yorktown Confining Unit underlying the site was encountered. Therefore, the shallow (Columbia)

2-8


aquifer was removed and any associated risk was mitigated. Restoration of the site involved the creation of tidal wetlands whereby the excavated landfill area was backfilled with clean fill necessary to achieve wetland grade elevations. With the waste and shallow aquifer removed, groundwater flow has re-established itself to discharge to the wetlands.

The minimal risk [Hazard Index (HI) 1.7 for manganese] from potable use of the deep groundwater of the Yorktown Aquifer was determined to be unrelated to the Site 2 landfill, as the manganese concentrations detected in deep groundwater samples at Site 2 were comparable to the concentration detected in an upgradient background well installed in the Yorktown Aquifer. Furthermore, construction of a potable supply well in low-lying or wetland areas is prohibited by Virginia’s Private Well Regulations (Virginia Department of Health, 1992) and Waterworks Regulations. Thus, no well for potable use could receive a permit.

2.7.3 Surface Water The ERA results concluded that there were minimal potential risks to aquatic life from site-related chemicals in surface water. Based on the complete removal of waste (including the groundwater in the shallow aquifer), soil, and marsh sediment that potentially contributed to surface water, and the transient nature of surface water, the concern for continued transport of contamination and risk has been eliminated.

2.8

2.9

No Further Action Necessary As demonstrated by the mitigation of potential site risks, Site 2 poses no unacceptable risk to human health or the environment. The Navy, in consultation with EPA and VDEQ, agree that NFA is required for Site 2. Consequently, with the exception of no action, no remedial action alternatives were considered and the development of remedial action objectives (RAOs) is not necessary. There are no principal threat wastes at the site and an NFA determination for Site 2 meets the statutory requirements of CERCLA Section 121 and the regulatory requirements of the NCP for protection of human health and the environment. No remedial response action will be performed at Site 2, and no restrictions on land use or exposure are necessary.

Documentation of Significant Changes The PRAP for Site 2 identified NFA as the preferred alternative. No members of the public attended the public meeting for the Site 2 PRAP, and no comments were received during the public comment period. Therefore, no significant changes were made to the preferred remedial action alternative identified in the PRAP.

2-9

SECTION 3

Responsiveness Summary

The participants in the public meeting held on August 8, 2005, included representatives of the Navy and the Commonwealth of Virginia. No members of the public attended the public meeting for the Site 2 PRAP, and no comments were received during the public comment period.

3-1

SECTION 4

References

A.T. Kearney, Inc., 1987. Supplement to the Interim Final RCRA Facility Assessment Report, Norfolk Naval Shipyard, Portsmouth, Virginia.

CH2M HILL, 1999. Draft Final Phase II Remedial Investigation and Feasibility Study Operable Unit 1 Scott Center Landfill, Norfolk Naval Shipyard, Portsmouth, Virginia.

CH2M HILL, 2001a. Final Phase II Remedial Investigation & Human Health Risk Assessment, Operable Unit 1, Scott Center Landfill, Norfolk Naval Shipyard, Portsmouth, Virginia.

CH2M HILL, 2001b. Final Ecological Risk Assessment, Paradise Creek, Norfolk Naval Shipyard, Portsmouth, Virginia.

CH2M HILL, 2002. HHRA for Lower Paradise Creek, Norfolk Naval Shipyard, Portsmouth, Virginia.

CH2M HILL, 2003a. Final Report – Development of Site-Specific Remediation Goals (RGs) for Marsh Creek Sediments Adjacent to Paradise Creek and the Scott Center and Paradise Creek Landfills, Norfolk Naval Shipyard, Portsmouth, Virginia.

CH2M HILL, 2003b. Final Work Plan for Evaluation of Paradise Creek Marsh Sediments Adjacent to Scott Center Landfill (OU1) and Paradise Creek Disposal Area (OU2), Evaluation of Marsh Sediments at the Former New Gosport Landfill, and Evaluation of Soil in the Berm Area of OU2, Norfolk Naval Shipyard, Portsmouth, Virginia.

CH2M HILL, 2003c. Final Waste Delineation Investigation for Operable Unit 1 – Site 2/Scott Center Landfill & Operable Unit 2 – Site 7/Paradise Creek Disposal Area, Norfolk Naval Shipyard, Portsmouth, Virginia.

CH2M HILL, 2004a. The Findings of Phase I Paradise Creek Marsh Sediment Sampling Adjacent to Scott Center Landfill (OU1) and Paradise Creek Disposal Area (OU2) and Remedial Action Considerations, Norfolk Naval Shipyard, Portsmouth, Virginia. January 2004.

CH2M HILL, 2004b. Final Engineering Evaluation/Cost Analysis for Scott Center Landfill (OU1) Site 2, Norfolk Naval Shipyard, Portsmouth, Virginia.

CH2M HILL, 2004c. Final Action Memorandum, Scott Center Landfill (OU1) Site 2, Norfolk Naval Shipyard, Portsmouth, Virginia.

CH2M HILL, 2004d. Final 100 Percent Submittal Specifications for Operable Unit 1, Site 2 – Scott Center Landfill, Norfolk Naval Shipyard, Portsmouth, Virginia.

ECOR Solutions, 2004. Draft Work Plan, Operable Unit 1, Site 2, Scott Center Landfill, Non-Time Critical Removal Action, Norfolk Naval Shipyard, Portsmouth, Virginia.

ECOR Solutions, 2005. Final Construction Completion Report, Non-Time Critical Removal Action, Operable Unit 1, Site 2, Scott Center Landfill, Norfolk Naval Shipyard, Portsmouth, Virginia.

4-1


Foster Wheeler Environmental Services, 1995. Final Remedial Investigation/Risk Assessment/ Feasibility Study Report, Norfolk Naval Shipyard, Portsmouth, Virginia.

IT Corporation, 1989. Remedial Investigation Interim Report, Norfolk Naval Shipyard, Portsmouth, Virginia.

NUS Corporation, 1986. Final Interim RCRA Facility Assessment Report, Norfolk Naval Shipyard, Portsmouth, Virginia.

Virginia Department of Health, 1992. Private Well Regulations [12VAC5-630-380(C)]

Virginia Department of Health. 1997. Notice and Description of Shellfish Area Condemnation Number 7, Hampton Roads.

Water and Air Research, Inc., 1983. Initial Assessment Study of the Norfolk Naval Shipyard.

4-2

Figures

City ofPortsmouth

City ofChesapeake

MainShip Yard

NewGosport

ScottCenterAnnex

SouthGate

Annex

Southern B

ranc

h of

the

Eliz

abet

h R

i ve r

City ofPortsmouth

ParadiseCreek

LandfillParadise Creek

0 1000 2000 Feet

N

CH2MHILL

Figure 2-1Location of Norfolk Naval Shipyard

Portsmouth, Virginia

File Path: v:\18gis\st-juliens\figures\sites3-6_ri.apr

Scott Center Landfill

Marsh Sediment

NNot to Scale

Figure 2-2Location of Scott Center Landfill

and Adjacent Marsh SedimentNNSY, Portsmouth, Virginia

ApproximateRemoval Boundary

Paradise Creek

Current and FutureRecreational

Users/Site Workers

Figure 2-3 (Sheet 1 of 2)Conceptual Site Model - Human Health Risk AssessmentSite 2, NNSY, Portsmouth, Virginia

Aquatic Organisms

Sediment

Sediment

Ingestion,Bioaccumulation,Bioconcentration

Aquatic Organisms

Ingestion, Dermal

Recreational Users

Recreational Users

Ingestion, Dermal

Current and FutureRecreational Users

Current and FutureRecreational

Users/Site Workers

SURFACESOIL

Discharge toSurface Water*

Groundwater FlowLeaching/Desorption

SOURCERELEASE

MECHANISMTRANSPORTMECHANISM

EXPOSUREPOINT

EXPOSUREMEDIA

EXPOSUREROUTE

PRIMARYRECEPTOR

SECONDARYRECEPTOR

IngestionBioaccumulation,Bioconcentration

Wind

Onsite

Offsite

Inhalation

Inhalation

Volatilization andDiffusion

Ambient Air (Vapors)

Ambient Air (Vapors)

Wind

Onsite

Offsite

Soil Disturbance

Dust and Vapors

Dust and Vapors

Onsite Exposed MaterialDirect Contact with Soil Ingestion,Dermal Absorption

Erosion

Surface Water

Site Workers

Site Workers

Future Site Workers/Residents/

Recreational Users

Onsite/Offsite GroundwaterIngestion, Dermal

Absorption, Inhalation(Volatiles)

Future ResidentialUsers

Inhalation

Inhalation

Complete Pathway

Incomplete Pathway

Legend

Surface Water

Surface Water

Current and Future SiteWorkers/Future

Residents/FutureRecreational Users

138623.AR.HH<36 HealthPath Site2>wdc.cac.12.20.99

Wind

Onsite

Offsite Ambient Air (Vapors)

Ambient Air (Vapors) Inhalation

Inhalation

Air (Dust)Air (Vapors)

Excavation ExposingThe Subsurface

Resulting In Direct Contact WithExposed Material and

Evaporation

Onsite Exposed MaterialIngestion

Dermal Absorption


SOURCERELEASE

MECHANISMTRANSPORTMECHANISM

EXPOSUREPOINT

EXPOSUREMEDIA

EXPOSUREROUTE

PRIMARY RECEPTOR SECONDARYRECEPTOR

Leaching /Desorption

(See Surface Soils)


Landfill GasMigration

Offsite

Onsite

Air

Air Inhalation

Inhalation

Inhalation,Dermal Absorption

Construction Worker

Construction Worker

Construction Worker

Figure 2-3 (Sheet 2 of 2)Conceptual Site Model - Human Health Risk AssessmentSite 2, NNSY, Portsmouth, Virginia

SUBSURFACESOIL

Complete Pathway

Incomplete Pathway

Legend

*Note- the soil to surface water pathways will be included under the Paridise Creekevaluation; therefore, it is depicted as an incomplete pathway for this evaluation

138623.AR.HH<36 HealthPath Site2>wdc.cac.12.20.99

Source Transport Pathways Exposure Media Exposure Route Receptors

Aquatic

Bent

hic

inve

rtebr

ates

Plan

ts

Wat

er c

olum

n-dw

ellin

g aq

uatic

life

Amph

ibia

ns

Rep

tiles

Bird

s

Mam

mal

s

Ingestion ∗ ∗ ∗ • •

Direct Contact • • • ∗ ∗ ∗ ∗

Ingestion • ∗ ∗ ∗ • •

Direct Contact • • ∗ ∗ ∗ ∗

Root Uptake •

Ingestion ∗ ∗ ∗ ∗ • •

Figure 2-4 Conceptual Site Model –

Ecological Risk Assessment Paradise Creek, NNSY, Portsmouth, Virginia

Biota Uptake/Accumulation

• - Exposure Route evaluated quantitatively ∗ - Exposure Route not evaluated quantitatively (see text)

Leaching/Desorption Sediment

Groundwater Discharge

Surface Water

Surface Runoff

• Paradise Creek Landfill

• Scott Center Landfill

• New Gosport

Landfill

Figure 2-5Confirmation Sample Grid

Scott Center LandfillNNSY, Portsmouth, Virginia

A1B1 C1 D1 E1

D2C2B2A2

BC3

CS12

CS13CS01

CS14

CS15

CS03

CS04CS02

CS05CS06

CS07

CS08CS09

CS10CS11

CS20 CS19

CS18CS17 CS16

Landfill Grid Confirmation SampleMarsh Sediment Grid Confirmation Sample

(1) J = Estimated value below laboratory detection limit(2) Clean up goal based upon the results of the HHRA; vanadium was not an ecological risk driver.(3) Background concentration established in the remediation goal investigation used to develop RACGs. No unacceptable ecological risk risk was identified; therefore, a site-specific RACG was not developed and confirmation samples were not collected as the background concentration was deemed protective.

MetalClean Up

GoalArsenic 24 16.1Barium 72 55.3 J(1)

Beryllium 2 1.5 JCadmium 1.1 0.58 JChromium 198 106Cobalt 98 30.1Copper 353 104Lead 400 238 JMercury 1.47 0.96Nickel 84 63.9 JSelenium 7 2 JVanadium 560(2) 72(3)

Zinc 643 377 J

Max Conc. Left in Place

Paradise Creek

NNot to Scale

Figure 2-6OU1 Site 2

Tidal Wetlands Site RestorationNNSY, Portsmouth, Virginia

final record of decision operable unit 1, site 2, scott ... · norfolk naval shipyard (nnsy)...

Documents