Final Explanation of Significant Differences Naval Weapons Station, Yorktown Site 3 – Group 16 Magazines Landfill 1.0 INTRODUCTION This Explanation of Significant Difference (ESD) to the 1999 Record of Decision (ROD) for soil and surface debris at Site 3, the Group 16 Magazines Landfill, Naval Weapons Station (WPNSTA) Yorktown, Virginia (the Site), was prepared in accordance with Section 117(c) of the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA) and Title 40 Code of Federal Regulations (40 CFR) Section 300.435(c)(2)(i) of the National Contingency Plan (NCP). The ROD was signed by the lead agency, the United States Department of the Navy (Navy), and the support agency, the United States Environmental Protection Agency (USEPA) Region 3, with concurrence from the Virginia Department of Environmental Quality (VDEQ) in June 1999 (Baker, 1999). The ROD addresses only soils and surface debris at the site. This ESD addresses soils, surface debris, and former buried waste. Sediments, surface water, and groundwater are currently under investigation and will be addressed in a future decision document. 1.1 Statement of Purpose This ESD documents a significant difference from that identified in the 1999 ROD in the extent, cost, and post-action residual concentrations of waste cleanup achieved at WPNSTA Yorktown Site 3. The extent of the action was significantly larger (approximately five times larger) than identified in the ROD as a result of the discovery of previously unknown buried dry cell batteries (127 tons) and galley waste (4,700 tons). Therefore, costs to complete this action nearly doubled from the expected ROD cost of $155,000. Post-action sampling confirmed that this action resulted in meeting residential soil cleanup levels versus the industrial soil cleanup levels required in the ROD. The ROD required excavation and removal of polycyclic aromatic hydrocarbon (PAH) contaminated soil that exceeded commercial/industrial cleanup levels and implementation of land use controls to restrict future residential use of the property. However, the remedial action completed in April 2000 consisted of excavation and removal of all waste and associated soil contamination to levels acceptable for unlimited use and unrestricted exposure (UU/UE) at Site 3 (OHM, 2001). This action eliminates all potential unacceptable human health and ecological risks (Baker, 2008). Site conditions now allow for UU/UE, negating the need for land use controls or 5-year reviews pursuant to CERCLA Section 121(c). 1.2 Public Participation This ESD and the documents forming the basis for issuing this ESD will become part of the Administrative Record (AR) File for WPNSTA Yorktown as per 40 CFR Section 300.825(a)(2) of the NCP. The AR file can be viewed by contacting Ms. Bonnie Capito, Librarian and Records Manager, Naval Facilities Engineering Command, Atlantic, at 757-322-4785 or [email protected]. This ESD and the documents forming the basis for issuing this ESD will also be available for 30 days after issuance of the ESD at the following Information Repository: 1 of 7
Transcript
Final Explanation of Significant Differences
Naval Weapons Station, Yorktown Site 3 – Group 16 Magazines Landfill
1.0 INTRODUCTION This Explanation of Significant Difference (ESD) to the 1999 Record of Decision (ROD) for soil and surface debris at Site 3, the Group 16 Magazines Landfill, Naval Weapons Station (WPNSTA) Yorktown, Virginia (the Site), was prepared in accordance with Section 117(c) of the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA) and Title 40 Code of Federal Regulations (40 CFR) Section 300.435(c)(2)(i) of the National Contingency Plan (NCP). The ROD was signed by the lead agency, the United States Department of the Navy (Navy), and the support agency, the United States Environmental Protection Agency (USEPA) Region 3, with concurrence from the Virginia Department of Environmental Quality (VDEQ) in June 1999 (Baker, 1999). The ROD addresses only soils and surface debris at the site. This ESD addresses soils, surface debris, and former buried waste. Sediments, surface water, and groundwater are currently under investigation and will be addressed in a future decision document.
1.1 Statement of Purpose This ESD documents a significant difference from that identified in the 1999 ROD in the extent, cost, and post-action residual concentrations of waste cleanup achieved at WPNSTA Yorktown Site 3. The extent of the action was significantly larger (approximately five times larger) than identified in the ROD as a result of the discovery of previously unknown buried dry cell batteries (127 tons) and galley waste (4,700 tons). Therefore, costs to complete this action nearly doubled from the expected ROD cost of $155,000. Post-action sampling confirmed that this action resulted in meeting residential soil cleanup levels versus the industrial soil cleanup levels required in the ROD.
The ROD required excavation and removal of polycyclic aromatic hydrocarbon (PAH) contaminated soil that exceeded commercial/industrial cleanup levels and implementation of land use controls to restrict future residential use of the property. However, the remedial action completed in April 2000 consisted of excavation and removal of all waste and associated soil contamination to levels acceptable for unlimited use and unrestricted exposure (UU/UE) at Site 3 (OHM, 2001). This action eliminates all potential unacceptable human health and ecological risks (Baker, 2008). Site conditions now allow for UU/UE, negating the need for land use controls or 5-year reviews pursuant to CERCLA Section 121(c).
1.2 Public Participation This ESD and the documents forming the basis for issuing this ESD will become part of the Administrative Record (AR) File for WPNSTA Yorktown as per 40 CFR Section 300.825(a)(2) of the NCP. The AR file can be viewed by contacting Ms. Bonnie Capito, Librarian and Records Manager, Naval Facilities Engineering Command, Atlantic, at 757-322-4785 or [email protected]. This ESD and the documents forming the basis for issuing this ESD will also be available for 30 days after issuance of the ESD at the following Information Repository:
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Virgil I. Grissom Public Library 366 DeShazor Dr. Newport News, Virginia 23506 (757) 369-3190 http://www.newport-news.va.us/library/libsys/locat/grissom/grissom.htm
In accordance with 40 CFR Section 300.435(c)(2)(i) of the NCP, a notice of availability and a brief description of this ESD will be published in the Daily Press and The Virginia Gazette within 30 days of issuance of this ESD. The ESD and documents forming the basis for issuing this ESD will be available in the Information Repository (Virgil I. Grissom Library) for a minimum of 30 days following this public notice of availability.
2.0 BACKGROUND The Site is located within WPNSTA Yorktown, a 10,624-acre installation located on the Virginia Peninsula in York and James Counties and the City of Newport News. WPNSTA Yorktown is bounded on the northwest by another Navy installation, commonly known as Cheatham Annex, and the King’s Creek Plantation resort community; on the northeast by the York River and Colonial National Historic Parkway; on the southwest by Route 143 and Interstate 64; and on the southeast by Route 238 and the community of Lackey.
WPNSTA Yorktown Site 3, the Group 16 Magazines Landfill, is a 2-acre area located between the Group 16 Magazines and the headwaters of Indian Field Creek within the northeastern portion of WPNSTA Yorktown (Figure 1). Although this site was named for its proximity to the Group 16 Magazines, this site’s operations are unrelated to any activities at the magazines.
2.1 Site Description and History Site 3, originally used for sand mining, became a landfill as depression areas created by mining activities were used for waste disposal. The Site 3 landfill reportedly operated from 1940 to 1970 and received an estimated 90 tons of waste. Wastes disposed included solvents, sludge from boiler cleaning operations, grease trap wastes, Imhoff tank skimmings containing oil and grease, and animal carcasses. The general topography is uneven with topographic highs at the northern and southwestern ends. Surface water runoff flows eastward toward Indian Field Creek.
2.2 Site Investigations and Contamination Site 3 soils were characterized as part of several investigations and actions beginning in 1984; these investigations are documented in the following AR files for WPNSTA Yorktown.
Document Title /Milestone Author/Date AR Document Number
Initial Assessment Study C.C. Johnson & Associates, Inc. and CH2M HILL, July 1984
00247
Confirmation Study Step IA (Verification) Round One and Two
Dames & Moore, 1986 and 1988 00256 and 00259
Final Remedial Investigation Interim Report Vesar, 1991 00812
Final Round One Remedial Investigation Report for Sites 1-9, 11, 12, 16-19, and 21
Baker and Weston, 1993 00313
Final Feasibility Study Sites 1 and 3 Baker, 1997 01158
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Document Title /Milestone Author/Date AR Document Number
Final Round Two Remedial Investigation Report Sites 1 and 3 (Volumes I and II)
Baker, 1998 00998 and 00999
Final Proposed Remedial Action Plan Site 1 – Dudley Road Landfill and Site 3 – Group 16 Magazines Landfill
Baker, 1998 01840
Final Record of Decision Operable Unit Nos. VIII and IX Site 1 – Dudley Road Landfill and Site 3 – Group 16 Magazines Landfill
Baker, 1999 01000
Final Report Remedial Action Sites 1 and 3, and SSA 22
OHM, 2001 01091
Final Technical Memorandum Documentation of Post-Remedial Action Site Conditions Site 3 –
Baker, 2008 02200
Group 16 Magazines Landfill
The following is a summary of key investigations, actions, and findings for Site soils and waste.
Final Round Two Remedial Investigation Report Sites 1 and 3 (Baker, 1998)
A PAH-contaminated soil hot spot was identified, and human health and ecological risk assessments were completed that considered two separate areas: Site 3 Proper, and PAH hot spot. Site 3 Proper included all sample locations except the PAH hot spot area. The human health risk assessment considered current (trespasser and construction workers) and future (residents) receptors.
Site 3 Proper Soil – No human health or ecological risks identified.
Site 3 PAH Hot Spot Soil – Potential cancer risks were identified for adult and adolescent trespassers and noncancer hazards were identified for construction workers based on reasonable maximum exposure (RME). However, based on more realistic central tendency exposure (CTE) assumptions, no unacceptable risks were identified for these receptors. Potential cancer risks and noncancer hazards were identified for future adult and child residents for both RME and CTE assumptions. Potential ecological risks were also identified.
Final Feasibility Study Sites 1 and 3 (Baker, 1997)
The Feasibility Study established final remediation goals for total carcinogenic PAHs (cPAHs): an ecological remediation goal was determined to be 44 milligrams per kilogram (mg/kg) total cPAHs (toxicity value from Long et al., 1995); a potential future human health residential land use remediation goal was determined to be 4.1 mg/kg; and a remediation goal protective of potential trespassers was determined to be 10 mg/kg. Alternatives evaluated were: (1) No Action, (2) No Action with Institutional Controls and Debris Removal, (3) Soil Excavation with Onsite Treatment and Debris Removal, and (4) Soil Excavation with Offsite Disposal and Debris Removal.
Final Record of Decision Operable Unit Nos. VIII and IX Site 1 – Dudley Road Landfill and Site 3 – Group 16 Magazines Landfill (Baker, 1999)
The ROD for Site 3 identified Alternative 4, removal and offsite disposal of soil posing unacceptable risks to human health and the environment, as the selected remedy. The major components of the remedy are:
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• Removal of surficial debris
• Excavation of PAH-contaminated soil within hot spot area that exceed commercial/ industrial levels; collecting confirmation samples.
• Proper disposal of PAH-contaminated soil
• Backfilling and vegetating excavation area
• Land use controls to prevent future residential use
• Five-year reviews
Final Report Remedial Action Sites 1 and 3, and SSA 22 (OHM, 2001)
Although the selected remedy identified in the ROD was to remove PAH-contaminated soils that exceeded commercial/industrial levels (10 mg/kg) within the PAH hot spot area, as excavation progressed and buried waste was encountered, the 2000 action was expanded to remove all waste at the Site (Site Proper and PAH hot spot). Approximately 432 tons of PAH-contaminated soil, drums, and dry batteries were removed. In addition, approximately 4,700 tons of galley waste (cardboard, glass bottles, metals cans) was also removed. Areas where contaminated soils and waste were removed received 3 to 8 feet (ft) of backfill. Figure 1 identifies the areas where surface debris and contaminated soil/buried debris were discovered and removed across the site.
Final Technical Memorandum Documentation of Post-Remedial Action Site Conditions Site 3 – Group 16 Magazines Landfill (Baker, 2008)
The remedial action completed in 2000 resulted in removal of all waste and PAH-contaminated soils to levels below a residential land use remediation goal of 4 mg/kg. Therefore, the land use control component of the remedy identified in the ROD to prevent future residential use with a requirement to conduct 5-year reviews no longer applies, as the action implemented resulted in removal of all waste sources and residual soil concentrations that allow for UU/UE.
2.3 Site Soils – Summary of Risks Prior to the 2000 remedial action, human health and ecological risks were evaluated in the Round Two Remedial Investigation (Baker, 1998). Potential unacceptable human health risks were identified for future adult and child residents exposed to soils within the PAH hot spot area for both RME and CTE assumptions. Although potential unacceptable risks were also identified under RME calculations for adult and adolescent trespassers and construction workers within the PAH hot spot area, these risks are considered manageable because no unacceptable risks were identified under CTE assumptions. PAHs and inorganics were also determined to present a potential unacceptable ecological risk within the PAH hot spot area. There were no unacceptable human health or ecological risks identified in Site soils outside the PAH hot spot area.
With completion of the remedial action and documentation in the Final Report Remedial Action Sites 1 and 3, and SSA 22 (OHM, 2001) to demonstrate that all waste had been removed, the technical memorandum Final Technical Memorandum Documentation of Post-Remedial Action Site Conditions Site 3 – Group 16 Magazines Landfill (Baker, 2008) was prepared to document that the action resulted in concentrations of cPAHs remaining in soils are at levels that allow for UU/UE and concluded the following.
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• Interviews with former Navy and VDEQ personnel involved in the 2000 remedial action confirm all waste had been removed and 3 to 8 ft of clean soil backfill was placed within excavated areas.
• Post-removal confirmation sample results are below the established residential soil cleanup level for cPAH of 1 mg/kg agreed to by the Navy, in partnership with USEPA Region 3, and VDEQ, which is acceptable for UU/UE and has been established as a protective threshold at other Installation Restoration Program (IRP) sites at WPNSTA Yorktown. These data demonstrate that soil within the PAH hot spot area meet human health and ecological cleanup levels protective for UU/UE.
• Round Two Remedial Investigation data for sampling points not included within the footprint of the remedial action demonstrate that soils outside the PAH hot spot area are also below levels acceptable for UU/UE. Select inorganics were identified as posing a potential human health risk (aluminum, antimony, arsenic, iron, and manganese) based on RME. However, no individual hazard quotient exceeded the acceptable noncancer hazard threshold of 1 and, because concentrations are consistent with WPNSTA Yorktown background, it was determined that these soils do not pose an unacceptable risk to child residents. Similarly, select inorganics that were identified as posing a potential ecological risk (aluminum, antimony, chromium, iron, lead, manganese, mercury, thallium, vanadium, and zinc) were determined to be at acceptable levels based on comparison to background and screening levels.
3.0 BASIS FOR THE ESD This ESD is necessary because the performance, scope, and cost of the remedy, as implemented, differs significantly from the remedy selected in the ROD. The selected remedy, as implemented, remediated the Site to levels significantly more stringent than required by the ROD, and consequently, cost approximately twice the amount predicted in the ROD. Because remedial actions resulted in removal of all waste and soil concentrations that allow for UU/UE, this ESD supported by information in the AR file, documents the basis for no further action with the removal of land use controls and elimination of 5-year reviews.
4.0 DESCRIPTION OF SIGNIFICANT DIFFERENCES The following are the significant changes to the Site 3 1999 ROD for soil and waste based on the results of the 2000 remedial action:
• All waste has been removed. • Sampling confirmed that remaining soils do not pose an unacceptable human health risk or
ecological risk, and residual soil concentrations meet UU/UE criteria.
• The removal area was significantly larger than expected, and, as a result, implementation costs nearly doubled.
• Land use controls prohibiting future residential property use are no longer required. • Five-year reviews are no longer required.
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Baker. 1998. Final Proposed Remedial Action Plan, Sites 1 and 3, Naval Weapons Station Yorktown, Yorktown, Virginia. May 1998. (Admin. Record No. 01840)
Baker. 1999. Final Record of Decision, Sites 1 and 3, Naval Weapons Station Yorktown, Yorktown, Virginia. June 1999. (Admin. Record No. 01000)
Baker. 2008. Final Technical Memorandum, Documentation of Post-Remedial Action Site Conditions, Site 3, Naval Weapons Station Yorktown, Yorktown, Virginia. February 2008. (Admin. Record No. 02200)
Baker and Weston. 1993. Final Round One Remedial Investigation Report, Sites 1-9, 11, 12, 16-19, and 21, Naval Weapons Station Yorktown, Yorktown, Virginia. July 1993. (Admin. Record No. 00313)
C.C. Johnson & Associates and CH2M Hill. 1984. Initial Assessment Study of Naval Weapons Station Yorktown, Yorktown, Virginia. July 1984. (Admin. Record No. 00247)
Dames & Moore. 1986. Confirmation Study Step 1A, Round One, Naval Weapons Station Yorktown, Yorktown, Virginia. June 1986. (Admin. Record No. 00256)
Dames & Moore. 1988. Confirmation Study Step 1A, Round Two, Naval Weapons Station Yorktown, Yorktown, Virginia. June 1988. (Admin. Record No. 00259)
Versar. 1991. Remedial Investigation Interim Report, Naval Weapons Station Yorktown, Yorktown, Virginia. July 1991. (Admin. Record No. 00812)
9.0 FIGURE Figure 1: Site 3 – Group 16 Magazines Landfill
