massachusetts military reservation · the massachusetts military reservation (mmr) on cape cod,...

Massachusetts Military Reservation

Explanation of Significant Differencesto the

Final Record of DecisionAreas of Contamination FTA-2/LF-2,PFSA/FS-10/FS-22, SD-2/FS-6/FS-8,

SD-3/FTA-3/CY-4, SD-4, and SD-5/FS-5Source Areas (September 1998)

FinalOctober 2000

Prepared by:AFCEE/MMR

Installation Restoration Program322 E. Inner Road Box 41

Otis ANGB, MA 02542-5028

TABLE OF CONTENTS

ABBREVIATIONS AND ACRONYMS ....................................................................................ii

1. INTRODUCTION................................................................................................................. 1

2. STATEMENT OF PURPOSE................................................................................................2

3. SITE HISTORY/CONTAMINATION...................................................................................33.1 AREA OF CONTAMINATION (AOC) SD-5 ..........................................................3

3.1.1 Summary of Site History ...........................................................................33.1.2 Summary of Site Characteristics................................................................. 4

3.2 CS-2 STUDY AREA................................................................................................63.2.1 Summary of Site History ...........................................................................63.2.2 Summary of Site Characteristics.................................................................8

4. DESCRIPTION OF THE SELECTED REMEDY FOR AOC SD-5 ........................................9

5. BASIS FOR THE EXPLANATION OF SIGNIFICANT DIFFERENCES ........................... 13

6. DESCRIPTION OF SIGNIFICANT DIFFERENCES OR NEW ALTERNATIVES ............ 14

7. STATUTORY DETERMINATION..................................................................................... 16

8. DECLARATION FOR THE EXPLANATION OF SIGNIFICANT DIFFERENCES........... 17

9. REFERENCES.................................................................................................................... 18

APPENDIX A FIGURES1. AOC SD-5 Site Features2. CS-2 Drainage Swale and AOC SD-53. CS-2 Study Area and Stormwater Drainage System4. Lab Data for the CS-2 Drainage Swale

APPENDDC B SUPPORT AGENCY COMMENTS

APPENDLX C PUBLIC PARTICIPATION COMPLIANCE

ABBREVIATIONS AND ACRONYMS

AFCEE Air Force Center for Environmental ExcellenceAOC Area of ContaminationAVLUBE Aviation Lubricating Oilbgs below ground surfaceCDM Camp, Dresser, and McKeeCOPC contaminant of potential concernCRQL Contract-Required Quantitation LimitCS Chemical SpillDSRP Drainage Structure Removal ProgramEDB ethylene dibromideEPA U.S. Environmental Protection AgencyBSD Explanation of Significant DifferencesFS Fuel SpillFTA Fire Training AreaIRP Installation Restoration ProgramLF LandfillMADEP Massachusetts Department of Environmental ProtectionMCL maximum contaminant levelMMR Massachusetts Military ReservationNCP National Contingency PlanNDEL Nondestructive Inspection LaboratoryNFA No Further ActionNPL National Priorities ListNGB National Guard BureauOU Operable UnitPAH polycyclic aromatic hydrocarbonsPCE PerchloroethyleneRAWP Remedial Action Work PlanRI Remedial InvestigationROD Record of DecisionSD Storm DrainageSI Site InspectionSTCL soil target cleanup levelSVOC semivolatile organic compoundTCE TrichloroethyleneTP Test PitTPH total petroleum hydrocarbonsUST underground storage tankVMB vehicle maintenance buildingVOC volatile organic compound

August, 2000

1. INTRODUCTION

This Explanation of Significant Differences (ESD) amends the Record of Decision(ROD) titled Areas of Contamination FTA-2/LF-2, PFSA/FS-10/FS-ll, SD-2/FS-6/FS-8,SD-3/FTA-3/CY-4, SD-4, and SD-5/FS-5 Source Areas [the "6 AOC ROD"] (AFCEE,

1998). The 6 AOC ROD addressed past releases of contaminants to soil and sediment at

the Massachusetts Military Reservation (MMR) on Cape Cod, Massachusetts, and wassigned by the Air Force Center for Environmental Excellence (AFCEE) and theEnvironmental Protection Agency's (EPA's) New England Region on September 25,

1998, and September 30, 1998, respectively. MMR is a National Priorities List (NPL) site

under the Comprehensive Environmental Response, Compensation, and Liability Act of1980 (CERCLA). 42 U.S. Code §§ 9601 et seq.

This ESD was developed in accordance with §117(c) of CERCLA, and §300.435(c)(2)(l)of the National Oil and Hazardous Substances Pollution Contingency Plan (NCP). Theformat of the ESD is in accordance with EPA's "A Guide to Preparing SuperfundProposed Plans, Records of Decision, and Other Remedy Selection DecisionDocuments." (USEPA 1999).

The Director of AFCEE and the Director of the Office of Site Remediation andRestoration, EPA New England have been delegated the authority to approve this ESD.

August, 2000

2. STATEMENT OF PURPOSE

This ESD to the 6 AOC ROD was initially proposed by AFCEE in a June, 2000 letter tothe EPA. In the process of preparing a draft Decision Document proposing "No FurtherAction" on the Chemical Spill No. 2 Study Area (CS-2) (CDM, 1997), AFCEE noted thata drainage swale at CS-2 contained elevated levels of soil contaminants. This drainageswale, although historically identified as part of CS-2, was also within the footprint of theStorm Drainage Ditch No. 5 (SD-5). As the horizontal extent of contamination at SD-5was to be further delineated in 2000, and remediation was scheduled to follow thisdelineation effort, AFCEE determined that it was more practical to add the CS-2 drainageswale to the future delineation and remediation efforts at SD-5. In addition, AFCEEnoted that the No Further Action Decision Document for CS-2 could be finalized

immediately, as residual risk associated with the remainder of this study area was withinregulatory limits. In response to AFCEE's letter, EPA directed AFCEE to prepare anESD to document the inclusion of the CS-2 drainage swale into the SD-5 AOC andexplain why the remedy selected in the 6 AOC ROD is the appropriate remedy for the

soils within the CS-2 drainage swale.

In essence, this ESD to the 6 AOC ROD removes the CS-2 drainage swale from the CS-2Study Area and adds it to AOC SD-5. The ESD will become part of the AdministrativeRecord for the 6 AOC ROD in accordance with the NCP (40 CFR 300.825(a)(2)). TheAdministrative Record is available for public review at the AFCEE InstallationRestoration Program Office (322 East Inner Rd., Otis Air National Guard Base,Massachusetts, 02542) Monday - Friday, 8 a.m. - 4 p.m., excluding federal and stateholidays.

August, 2000

3. SITE HISTORY/CONTAMINATION

The 6 AOC ROD addressed past releases of contaminants to soil and sediment at thefollowing six Areas of Contamination (AOCs) at the MMR on Cape Cod, Massachusetts:

• Fire Training Area No. 2 and Landfill No. 2 (FTA-2/LF-2)• Petroleum Fuels Storage Area, Fuel Spill No. 10, and Fuel Spill No. 11

(PFSA/FS-10/FS-ll)• Storm Drainage Ditch No. 2, Fuel Spill No. 6, and Fuel Spill No. 8

(SD-2/FS-6/FS-8)• Storm Drainage Ditch No. 3, Fire Training Area No. 3, and Coal Storage Yard

No. 4 (SD-3/FTA-3/CY-4)• Storm Drainage Ditch No. 4 (SD-4), and• Storm Drainage Ditch No. 5 and Fuel Spill No. 5 (SD-5/FS-5)

Groundwater contamination associated with these 6 AOCs is being addressed as part of

separate studies and response actions. Actions implemented as a result of the 6 AOCROD will support future groundwater remedial actions by minimizing future groundwatercontamination.

This ESD adds a drainage swale that had been considered part of the CS-2 Study Area tothe horizontal footprint of the SD-5/FS-5 AOC. As the other AOC's are unaffected bythis ESD, including FS-5, the ESD focuses strictly on the SD-5 AOC, including site

history and selected remedy as outlined in the ROD, and how the inclusion of the CS-2drainage swale affects this section of the ROD.

3.1 Area of Contamination (AOC) SD-5:

3.1.1 Summary of Site History

AOC SD-5 includes a storm drainage swale, also known as the Central Drainage Swale(see Figure 1 (Appendix A)). Possible contamination sources near SD-5 include anaircraft maintenance ramp, two underground fuel storage/transfer systems (Aquafarms), aNondestructive Inspection Laboratory (NDEL), and a Corrosion Control Shop. Furtherinformation about the SD-5 AOC can be found in the IRP's administrative record for this

August, 2000

site including the Remedial Investigation (Hazwrap, 1993), Feasibility Study (ABB-ES,1997) and 6 AOC ROD (AFCEE, 1998). The following items summarize the history ofAOC SD-5:

• 1950s. SD-5 began receiving stormwater runoff from a number of sourcesincluding the Eastern and Western Aquafarms, the former NDIL, the CorrosionControl Shop, and the Permanent Field Training Site hangar.

• 1985. Field investigations evaluated liquid and sludge in the NDIL leaching welland nearby soil.

• 1988. A SI was performed to assess the presence of soil and groundwatercontamination.

• 1989. A RI was performed to characterize the nature and distribution of sediment,soil, and groundwater contamination.

• 1993. A supplemental RI was performed to further characterize contaminationand evaluate site risks.

• 1994. The NDIL and Corrosion Control Shop were demolished and removed.• 1994. Two 12,000-gallon underground storage tanks were removed from the

Aviation Lubricating Oil (AVLUBE) area as part of the Fuel System UpgradeProgram.

• 1994/1995. A total of 17 underground storage tanks, including all six25,000-gallon tanks at the Western Aquafarm, all four 25,000-gallon tanks at theEastern Aquafarm, and seven 550-gallon tanks associated with water separatorcontrol pits were removed.

• 1996. The NDIL leaching well and surrounding soil were removed as part of theDrainage Structure Removal Program (DSRP).

• 1997. A Feasibility Study was performed to evaluate approaches to controlpotential site risks.

• 1997. The 6 AOC Proposed Plan was published which outlined remedialstrategies for SD-5, among others.

• 1997/1998. Public Comment Period for the 6 AOC Proposed Plan.• 1998. 6 AOC ROD signed.

3.1.2 Summary of Site Characteristics

AOC SD-5 is located in the central part of the MMR cantonment area between NorthInner Road and Lingley Avenue on the north and south, respectively, and Base RunwayNo. 5 on the east, approximately 3,000 feet from the southern MMR boundary (ABB-ES,1996e). The AOC occupies approximately 40 acres at the northern end of a naturaldrainage swale, known as the Central Drainage Swale, that formerly extended southwardfor more than 10,000 feet toward Ashumet Pond. AOC SD-5 extends approximately2,000 feet along an unfilled portion of the drainage swale and varies in width from

August, 2000

approximately 750 to 1,200 feet. AOC SD-5 is within the flightline security area. Accessto areas within the flightline area is controlled with fences and guard posts, and activitiesnot related to aircraft operations are limited and strictly controlled. Fences around theflightline areas are inspected daily by base security. These site access restrictions areexpected to remain in place through the duration of the current lease (expiration date of2026) and the planned 25-year renewal.

The Central Drainage Swale has become overgrown with trees with small grassy areasinterspersed. Floodplains and wetlands are not known to exist at AOC SD-5, andendangered species are not known to reside there. The Central Drainage Swale is up to

25 feet below the grade of the flightline area. The Central Drainage Swale at AOC SD-5receives stormwater runoff from approximately 100 acres of paved runways and rampsthrough an extensive stormwater drainage system. The swale is unlined and water that

does not evaporate or infiltrate, flows south to an unlined 1-acre Stormwater InfiltrationBasin. During extensive storm or runoff events, the Stormwater Infiltration Basin

overflows into two buried 72-inch-diameter pipelines, flows southward beneath AOCFTA-2/LF-2, and discharges to Study Area SD-1.

AOC SD-5 is divided into the following three source-area operable units (OUs); seeFigure 1 (Appendix A):

• SD-5 A: the NDIL and the Corrosion Control Shop• SD-5B: the Western Aquafarm, AVLUBE Barrel Storage Area, and Refueler

Truck Park Area• SD-5C: the Eastern Aquafarm, Permanent Field Training Site, Fuel Spill No. 5,

and Central Drainage Swale

As only the SD-5C Operable Unit is affected by the inclusion of the CS-2 drainage swalein the 6 AOC ROD through this ESD document, the SD-5A and SD-5B operable unitswill not be further discussed.

SD-5C Operable Unit. Contamination within the SD-5C OU is present in surface andsubsurface soils. The surface soil contamination is primarily inorganics at concentrationsabove MMR background concentrations. In isolated areas, subsurface soil contaminationis also present in the form of VOCs with the potential to leach to ground water.

August, 2000

Within the Central Drainage Swale, chromium, copper, lead, and zinc are present insurface soil at most of the sampled test-pit locations at concentrations above background.Metals do not appear to be uniformly distributed across the drainage ditch, but instead areconcentrated at outfalls.

For subsurface soil, the VOCs TCE (33 ^g/kg) and benzene (59 ug/kg) were detected atTP-9 and TP-32, respectively. TP-9 is at the outfall for the former NDIL leaching well;

TP-32 is located within the Stormwater Infiltration Basin. Based on analytical resultsfrom nearby test pits and observations at all the test pits, the vertical distribution of theseVOCs is interpreted to be less than 6 feet in depth. The aerial distribution of the VOCs isalso limited because they were not detected in nearby subsurface soil.

Groundwater Contamination Assessment. Groundwater beneath AOC SD-5 iscontaminated by solvent-related compounds that likely leached from the NDIL drainagestructure. In addition, fuel-related contamination in groundwater is likely to haveoccurred as a result of leaks or spills from the Western Aquafarm. Maximumconcentrations of TCE (270 ug/L) were detected above the MCL (5 ng/L) in the area ofthe NDIL drainage structure. PCE (5 ug/L) and 1,2-DCE (110 ug/L) were also detectedat or above their respective MCLs of 5 and 70 ng/L in the area of the NDEL drainagestructure. At the Western Aquafarm, one total lead concentration of 31.4 ng/L wasmeasured above the MCL of 15 ug/L. In addition, BEHP (up to 25 ng/L) andethylbenzene (910 ng/L) were detected in monitoring wells downgradient of the WesternAquafarm above their MCLs of 6 and 700 ng/L, respectively.

3.2 CS-2 Study Area

3.2.1 Summary of Site History

The Chemical Spill No. 2 (CS-2) Study Area, located just west of the AOC SD-5 (SeeFigure 3 (Appendix A)), includes the former location of three U.S. Army regimentalmotor pools at Blocks 2, 4, and 5 on East Truck Road, as well as subsurface structures

August, 2000

associated with former Building 3202, a printing shop and officer's club adjacent toBlock 2. CS-2 was identified in Phase I, Records Search, Task 6 (E.C. Jordan Co. 1986)as a potential source of contamination based on large quantities of waste oils, solvents,antifreeze, battery electrolyte, paint, kerosene, and fuels that reportedly were generatedfrom vehicle maintenance activities at the motor pools. Additionally, metals reportedlywere commingled with these wastes. More detailed information about the CS-2 Study

Area can be found in the draft Decision Document which is available for public commentfrom August 28, 2000, to September 26, 2000.

Since the CS-2 drainage swale (which is to be re-designated as part of the AOC SD-5) islocated on the northeast corner of Block 2, investigative and remedial efforts at Blocks 4,5, and Building 3202 will not be further discussed.

The Block 2 motor pool, which was active from 1941 to 1946, originally consisted of one

vehicle maintenance building (VMS) one gas station, and a couple of supply/storagebuildings. Subsequent to 1946, the above grade structures of the motor pool were

removed. Investigative and remedial efforts focused on the subsurface structures related

to the motor pool, in addition to its perimeter area that received surface runoff from thepavement.

The CS-2 drainage swale locally received stormwater surface runoff from the Block 2motor pool pavement. Based on visual observations and historic stormwater drainageblueprints, however, it appears to have been primarily constructed as an outlet forstormwater leading from a historic stormwater drainage system for East Outer Road (seeFigure 3, Appendix A). The drainage swale is approximately 8-feet wide, 3-feet deep,and 150-feet long. It empties out into a grassy plain that is part of the SD-5C OperableUnit described previously. The base of the drainage swale was originally lined withconcrete, however the concrete blocks have broken up over time due to historicstormwater flow and vegetation, and now lie as rubble in the swale, disrupting the flow ofstormwater. The drainage swale has become overgrown with trees and with small grassyareas interspersed.

August, 2000

The Block 2 motor pool and CS-2 drainage swale were investigated during a 1993 SiteInvestigation. Confirmational soil sampling events of the drainage swale also occurred in1995 and 1999. The Block 2 motor pool subsurface structures and adjacent contaminatedsoils were removed as part of the Drainage Structure Removal Program in 1996 (Figure3, Appendix A). Soils from the CS-2 drainage swale were not removed as part of thiseffort.

3.2.2 Summary of Site Characteristics

The results of the soil sampling in the CS-2 drainage swale indicate the following:

Surface Soil: Polycyclic aromatic hydrocarbons (PAHs - Benzo(a)anthracene,Benzo(a)pyrene, Benzo(b)fluoranthene, Dibenz(a,h)anthracene, Indeno(l,2,3-cd)pyrene),pesticides (Dieldrin), PCBs (Aroclor-1260), and inorganics (arsenic, chromium, lead,vanadium) were detected above cleanup standards in surface soil samples (0-2' belowground surface (bgs)) collected from the swale. Other inorganics were also detectedabove the maximum MMR background concentrations as defined by the MMR RiskAssessment Handbook (ASG, 1994). See Figure 4 (Appendix A) for a summary oflaboratory analytical results.

Subsurface Soil: Concentrations of contaminants similar to those found in surface soilsamples were detected in the one subsurface soil sample (2-3' bgs) collected within thedrainage swale. Inorganics exceeded MMR background for subsurface soils. See Figure 4(Appendix A) for a summary of laboratory analytical results.

Groundwater: Groundwater samples collected from monitoring wells installed at CS-2had contaminant concentrations below applicable Maximum Contaminant Levels (MCL),and below EPA risk criteria.

August, 2000

4. DESCRIPTION OF THE SELECTED REMEDY FOR AOC SD-5

As originally described in the 6 AOC ROD, the selected remedy for AOC SD-5 isExcavation and Asphalt-batching. This alternative provides institutional and engineeringcontrols to limit exposure to site-related contaminants and to reduce source-areacontaminant concentrations to protective levels. The remedy does not include amanagement of migration component. Groundwater contamination attributed to AOCSD-5 is being addressed by the SD-5 North Groundwater Plume Extraction, Treatment,

and Reinjection System and the SD-5 South Recirculating Well System. This ESD doesnot change the selected remedy for AOC SD-5; it simply ensures that the CS-2 drainageswale is included in the horizontal extent of contamination delineated and remediated aspart of AOC SD-5.

Soil Target Cleanup Levels (STCLs). Based upon data developed in the RI and thePRA and summarized in the Feasibility Study, remedial actions are warranted at AOC

SD-5 to address risks associated with possible direct contact exposure to lead and TPH

contaminated source-area soils. Remedial actions are also warranted to protect ecologicalreceptors from maximum concentrations of site contaminants.

In addition, available data suggest that source-area soils may be a source of release ofVOCs to groundwater. Such a release could result in an unacceptable risk to those whodrink groundwater at or downgradient of the source area. Therefore, the STCLs

established for the DSRP at MMR (HAZWRAP, 1996) were used to estimate residualsoil levels that will be protective of future groundwater quality.

The STCLs are consistent with ARARs for groundwater, attain USEPA'srisk-management goal for remedial actions, and have been determined by AFCEE,USEPA, and MADEP to be protective. These cleanup levels must be met at thecompletion of the remedial action at the limits of STCL exceedance established duringpre-design confirmation soil sampling.

August, 2000

Description of Remedial Components. The selected remedy for AOC SD-5 isExcavation and Asphalt-batching. Key components of this alternative, as originallydescribed in the 6 AOC ROD, include:

• mobilization and site preparation

• performing pre-excavation confirmation soil sampling to confirm the horizontaland vertical distribution of contamination exceeding TPH and inorganic STCLs atsix locations and VOCs, TPH, and inorganics at the remaining two locations

• excavating soil exceeding cleanup criteria

• transporting excavated soil to an onsite asphalt-batching facility for testing and

treatment

• collecting post-excavation confirmation samples from the excavation perimeters

for analysis for TPH and inorganics at six of the proposed cleanup locations andfor VOCs, TPH, and inorganics at the remaining two locations

• backfilling and restoring excavations with clean borrow material

• using the asphalt-emulsion-coated product as a paving subgrade material atselected locations at MMR

• maintaining institutional controls that restrict site access and limit potentialhuman exposure to contaminants

• performing five-year site reviews

Each of these components is described in the following paragraphs:

Mobilization and site preparation. Mobilization and site preparation will includeprocuring necessary subcontractors, purchasing equipment, identifying undergroundutilities, clearing brush and trees, and constructing temporary access roads.

Performing pre-excavation confirmation soil sampling. AFCEE will performpre-excavation sampling to confirm the horizontal and vertical distribution of

August, 200010

contamination exceeding TPH and inorganic STCLs at six locations and VOCs, TPH, and

inorganics at the remaining two locations.

Excavating sediment/surface soil exceeding cleanup criteria. AFCEE will excavate areasidentified for remediation using backhoes, excavators, dredges, or other appropriateconstruction equipment. Based on available data and the PRA, up to 9,400 cy of material

may need to be excavated. Details of proposed sampling and analysis, excavation, andbackfill/restoration activities will be presented in a Remedial Action Work Plan (RAWP)and/or in design plans to be reviewed and approved by regulatory agencies prior toimplementation.

Transporting excavated soil to an onsite asphalt-batching facility for testing and

treatment.

Samples of the excavated soil will be collected and analyzed to assess whether the soilmust be treated/disposed of as a hazardous substance. One TCLP sample will be collectedper 100 cy of excavated material or as directed by the asphalt-batching subcontractor. In

lieu of TCLP analysis, total concentrations in soil may be used when total concentrationsare less than the theoretical concentration at which TCLP criteria would be exceeded.Soils considered hazardous will be disposed of ofFsite at a permitted treatment, storage,and disposal facility. Non-hazardous soils and those meeting threshold criteria will betransported to an onsite facility for asphalt-batching. In addition, analytical data will becompared to threshold concentrations for soil recycling facilities contained in theMassachusetts "Interim Remediation Waste Management Policy for PetroleumContaminated Soils" to assess acceptability for cold-mix asphalt-batching. Details of theasphalt-batching treatment process and associated testing will be presented in a RAWPand/or design plans and specifications to be reviewed and approved by USEPA andMADEP prior to implementation.

Collecting post-excavation confirmation samples from the excavation perimeter foranalysis for chromium, lead, and zinc. Confirmation samples will be collected from theperimeter of the excavations (post excavation) and analyzed for the organics and

August, 200011

inorganics to confirm that all surface soil contaminants exceeding STCLs for thesechemicals have been removed.

Backfilling and restoring excavations with clean borrow material. Following completion

of excavation activities, the excavations will be backfilled and restored to original gradewith clean fill material.

Using the asphalt-emulsion-coated product as a paving subgrade material at MMR.Asphalt-batched material will be used as paving subgrade material at selected locations atMMR. A minimum ll/2-inch wear coat will be placed over the asphalt-batched material.

Maintaining institutional controls that restrict site access and limit potential humanexposure to contaminants. To limit potential human exposure to site-related

contaminants, AFCEE will maintain site access restrictions at AOC SD-5 that are

consistent with current flightline security measures. Controls such as fences will beinspected and maintained/repaired not less than annually. Overall protectiveness will be

assessed during five-year site reviews. Alternately, if AFCEE can demonstrate, based oncurrently available or newly acquired data, that site access restrictions can be relaxed or

removed while protection of human health is maintained, AFCEE may petition USEPA

for such a relaxation or removal of restrictions.

Performing five-year site reviews. Because the assumptions of the risk assessment atAOC SD-5 do not allow unrestricted site use, and to provide an opportunity for review ofthe performance of the selected remedy, AFCEE will perform five-year site reviews forAOC SD-5. During the five-year review, AFCEE will review monitoring and otherpertinent data to assess whether the selected remedy remains protective of human healthand the environment and whether additional remedial action is appropriate.

August, 200012

5. BASIS FOR THE EXPLANATION OF SIGNIFICANT DIFFERENCES

In the process of preparing a draft Decision Document proposing "No Further Action" on

the CS-2 Study Area, AFCEE noted that a drainage swale at CS-2 still contained elevatedlevels of soil contaminants above STCLs which were similar to those found within AOC

SD-5. This drainage swale, although historically identified with CS-2, was also withinthe footprint of SD-5. As the horizontal extent of contamination at SD-5 was to be

further delineated in 2000, and necessary remediation was scheduled to follow thisdelineation effort, AFCEE determined that it was more practical to add the CS-2 drainage

swale to the future delineation and remediation efforts at SD-5 and remove the CS-2

drainage swale from the defined limits of the CS-2 Study Area. Approval of this ESD

document ensures that the extent of contamination identified in the CS-2 drainage swalewill be properly delineated as part of the SD-5 delineation, and affected soils will beexcavated and remediated.

August, 200013

6. DESCRIPTION OF SIGNIFICANT DIFFERENCES OR NEWALTERNATIVES

Although the CS-2 drainage swale is already within the defined footprint of the SD-5COperable Unit, the CS-2 drainage swale was previously considered part of the CS-2

Study Area. The type of contamination, volume and associated costs of the CS-2drainage swale to be excavated and remediated were not considered in the feasibilitystudy for AOC SD-5. The surface soil contamination associated with the SD-5COperable Unit is primarily inorganics at concentrations above MMR background

concentrations. In isolated areas, subsurface soil contamination is also present in the formof VOCs with the potential to leach to groundwater. Surface soil contamination

associated with the CS-2 drainage swale is present in the form of polycyclic aromatichydrocarbons, pesticides and inorganics.

In essence, the CS-2 drainage swale will become part of the SD-5C Operable Unit of

AOC SD-5, and the remedy selected for AOC SD-5 in the 6 AOC ROD will address the

former CS-2 drainage swale as well as the rest of SD-5. Contaminated soils within theCS-2 drainage swale will be excavated until soil samples at the excavation limits meet

STCL criteria. The excavated soils will be sampled and asphalt batched in accordancewith the criteria detailed in the 6 AOC ROD. Based on the lab data previously collectedfrom the CS-2 drainage swale, it is estimated that approximately an extra 100 cubic yards(150' long, 8' wide, and 2' deep +10%) will be excavated as part of the SD-5 excavationeffort. Soil sampling and analysis to ensure full contamination delineation of the formerCS-2 drainage swale and confirm clean closure should cost an additional $5,000. Thewaste soil is anticipated to be classified as non-hazardous waste. Based on currentestimated costs to excavate and asphalt batch these 100 cubic yards, this additionalexcavation/asphalt batch effort is estimated to cost approximately an additional $40,000($400/cubic yard). The cost per cubic yard was generated using estimates from theRemedial Action Work Plan for SD-5 (TN & Associates, 2000). This additional workand small change in overall scope (100 cubic yards) and cost ($45,000) to the 6 AOCROD is not expected to change the expected outcome outlined in the Record of Decision.

August, 200014

In summary, the selected remedy described in Section 4 of this BSD remains unchanged,with the exception that approximately 100 cubic yards from the CS-2 drainage swale, andsome additional sampling is added to this effort.

August, 200015

7. STATUTORY DETERMINATION

This modified remedy is consistent with CERCLA §121, and to the extent practicable,the NCP. The remedy is protective of human health and the environment, complies withfederal and Commonwealth of Massachusetts requirements that are legally applicable orrelevant and appropriate to the remedial action, and is cost-effective. The remedy utilizespermanent solutions and alternative treatment technologies to the maximum extentpracticable. In addition, the remedy satisfies the statutory preference for treatment thatreduces toxicity, mobility, or volume as a principal element.

August, 200016

8. DECLARATION FOR THE EXPLANATION OF SIGNIFICANT

DIFFERENCES FOR THE 6 AOC ROD

For the foregoing reasons, by my signature below, I concur and recommend the issuance

of an Explanation of Significant Differences to the Final Record of Decision for Areas ofContamination FTA-2/LF-2, PFSA/FS-10/FS-ll, SD-2/FS-6/FS-8, SD-3/FTA-3/CY-4,

SD-4, and SD-5/FS-5 Source Areas (AFCEE, 1998) and the changes stated therein.

CE CENTER FOR ENVIRONMENTAL EXCELLENCE

'GARDireCenter

19 Oct 00

ERICKSON, P.E.r Fore

Environmental Excellence

DATE

UNITED STATES ENVIRONMENTAL PROTECTION AGENCY

DATEOffice of Site Remediation and RestorationNew England Region

17August, 2000

COMMONWEALTH OF MASSACHUSETTSEXECUTIVE OFFICE OF ENVIRONMENTAL AFFAIRSDEPARTMENT OF ENVIRONMENTAL PROTECTION20 RIVERSIDE DRIVE, LAKEVILLE, MA 02347 508-946-2700

ARGEO PAUL CELLUCCIGovernor

JANE SWIFTLieutenant Governor

Mr. Robert M. Gill •?;?Remediation Program ManagerHQ AFCEE/MMR322 East Inner RoadOtis ANG Base, Massachusetts 02542

BOB DURANDSecretary

LAUREN A. LISSCommissioner

October 24,2000

RE: BOURNE-BWSC-4-0037Massachusetts MilitaryReservation, FTA-2/LF-2,PFSA/FS-10/FS-ll, SD-2/FS-6/FS-8, SD-3/FTA-3/CY-4, SD-4, andSD-5/FS-5, Explanation ofSignificant Differences,Concurrence

Dear Mr. Gill:

The Department of Environmental Protection (the "Department") has reviewed thedocument titled "Explanation of Significant Differences to the Final Record of Decision, Areasof Contamination FTA-2/LF-2, PFSA/FS-10/FS-ll, SD-2/FS-6/FS-8, SD-3/FTA-3/CY-4, SD-4, and SD-5/FS-5 Source Areas" (the "ESD") dated August 2000 and prepared for the Air ForceCenter for Environmental Excellence (AFCEE).

The ESD amends the Record of Decision, Areas of Contamination FTA-2/LF-2,PFSA/FS-10/FS-ll, SD-2/FS-6/FS-8, SD-3/FTA-3/CY-4, SD-4, and SD-5/FS-5 Source Areas[the "6 AOC ROD"] (AFCEE 1998). The 6 AOC ROD addressed past releases of contaminantsto soil and sediment at the Massachusetts Military Reservation (MMR) on Cape Cod,Massachusetts, and was signed by AFCEE and the Environmental Protection Agency's (EPA's)New England Region in September 1998, with concurrence from the Department.

In the process of preparing a draft Decision Document proposing "No Further Action" onthe Chemical Spill No. 2 Study Area (CS-2) (COM, 1997), AFCEE noted that a drainage swaleat CS-2 contained elevated levels of soil contaminants. This drainage swale at CS-2, althoughhistorically identified as part of CS-2, was also within the footprint of the Storm Drainage DitchNo. 5 (SD-5). As the horizontal extent of contamination at SD-5 was to be further delineated in2000 and remediation was scheduled to follow this delineation effort, AFCEE determined that itwas more practical to add the CS-2 drainage swale to the further delineation and remediationefforts at SD-5. In addition, AFCEE noted that the No Further Action Decision Document forCS-2 could be finalized immediately, as residual risk associated with the remainder of this study

This information is available in alternate format by calling our ADA Coordinator at (617) 574-6872.

DEP on the World Wide Web: http://www.magnel.state.ma.us/deptj> Printed on Recycled Paper

area was within regulatory limits. In response to AFCEE's letter, EPA directed AFCEE toprepare an ESD to document the inclusion of the CS-2 drainage swale into the SD-5 AOC andexplain why the remedy selected in the 6 AOC ROD is the appropriate remedy for the soilswithin the CS-2 drainage swale. This ESD to the 6 AOC ROD removes the CS-2 drainage swalefrom the CS-2 Study Area and adds it to AOC SD-5.

The Department concurs with the ESD.

Please incorporate this letter into the Administrative Record for Areas of ContaminationFTA-2/LF-2, PFSA/FS-10/FS-ll, SD-2/FS-6/FS-8, SD-3/FTA-3/CY-4, SD-4, and SD-5/FS-5. Ifyou have any questions regarding this letter, please contact Leonard J. Pinaud at (508) 946-2871.

Paul Taurasi, P.E.Regional Director

T/LP/HC/mwC\esdapv.doc

Cc: DEP-SEROATTN: Mildred Garcia-Surette, Deputy Regional Director

Leonard J. Pinaud, Chief, Federal Facilities Remediation Section

Distributions: SERO8MBPlume Containment TeamPublic Information TeamLong Range Water Supply PATBoards of SelectmenBoards of Health

Page 2

9. REFERENCES

ABB-ES, 1997 Six Areas of Contamination Source Area Feasibility Study, InstallationRestoration Program; Massachusetts Military Reservation; Oak Ridge, Tennessee,November

AFCEE, 1998 Record of Decision Areas of Contamination FTA-2/LF-2, PFSA/FS-10/FS-11, SD-2/FS-6/FS-8, SD-3/FTA-3/CY-4, SD-4, and SD-5/FS-5 Source Areas (AFCEE,1998), Hazardous Waste Remedial Action Program (HAZWRAP); InstallationRestoration Program; Massachusetts Military Reservation; Oak Ridge, Tennessee;September.

Automated Sciences Group, 1994 Risk Assessment Handbook, Massachusetts MilitaryReservation, Cape Cod Massachusetts, Hazardous Waste Remedial Actions Program,Lockheed Martin Energy Systems, Inc., Oak Ridge, Tennessee, September.

CDM, 1997 Decision Document for Chemical Spill (CS) Site No. 2, COM FederalPrograms Corporation; Installation Restoration Program; Massachusetts MilitaryReservation; Prepared for HAZWRAP, Cambridge, MA; March

E.G. JORDAN, Co. 1986 U.S. Air Force Installation Restoration Program, Phase I:Records Search, Air National Guard, Camp Edwards (ARNG), U.S. Air Force andVeterans Administration Facilities at Massachusetts Military Reservation,Massachusetts, Task 6. Oak Ridge National Laboratory, Oak Ridge, Tennessee.December

HAZWRAP, 1993 Remedial Investigation Report Stormwater Drainage Disposal SiteNo. 5 (SD-5) Including Fuel Spill No. 5 (FS-5), Installation Restoration Program;Massachusetts Military Reservation; Oak Ridge, Tennessee, November

HAZWRAP, 1996 Soil Target Cleanup Levels, DSRP, Installation Restoration Program;Massachusetts Military Reservation; Oak Ridge, Tennessee, January

TN & ASSOCIATES, 2000. Volume 1 - Cold Mix Asphalt Batching, 100% Design For:CS-16/CS-17, CS-10/FS-24, SD-5/FS-5, FS-9, SD-3/FTA-3/CY-4, SD-4, SD-2/FS-6/FS-8,CS-5, CS-11, FS-18, CS-4(USCG)/FS-1(USCG), FS-7, DDOU, Installation RestorationProgram; Massachusetts Military Reservation; Oak Ridge, Tennessee, April

USEPA, 1999 A Guide to Preparing Superfund Proposed Plans, Records of Decision,and Other Remedy Selection Decision Documents, Office of Solid Waste and EmergencyResponse, EPA 540-R-98-031, OSWER 9200.1-23P, PB98-963241, July.

August, 200018

APPENDIX AFIGURES

CentralDrainage

Swale

(ApproximateLocation)

StormwalarInfHlration

72-inchdameter

Storm Drains(oSO-1

Drainage Ditch

| | Existing Building

[j3117J Former BuHding

1 * I Drainage Ditch

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—~- FtowOiractkm

—— —— Approximate Boundary of OU

^—•^ Approximal* Boundary <rt AOCHarding Lawson Associate*

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SITE FEATURESAT AOC SO-S^S-SApproximate Scale in Feet

MSTALLATION RESTORATION PROGRAMMASSACHUSETTS MKTARV RESERVATION

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Topographic Contour

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i 300

Scale in Feet

Q| JACOBS ENGINEERING

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APPENDIX BSUPPORT AGENCY COMMENTS

Appended are written comments received by AFCEE from EPA and the Massachusetts Department ofEnvironmental Protection Agency on a draft version of this ESD submitted to the EPA and DEP in July2000. Their comments were incorporated into this August, 2000 draft version of the ESD as detailed inAFCEE's response to those comments that are also appended.

COMMONWEALTH OF MASSACHUSETTSEXECUTIVE OFFICE OF ENVIRONMENTAL AFFAIRSDEPARTMENT OF ENVIRONMENTAL PROTECTION20 RI\£ERSLQE DRIVE, LAKEVILLE, MA 02347 508-946-2700

ARGEO PAUL CELLUCCIGovernor

JANE SWIFTLieutenant Governor

Mr. Robert M. GillRemediation Program ManagerHQ AFCEE/MMR322 East Inner RoadOtis ANG Base, Massachusetts 02542

BOB DURANDSecretary

LAUREN A. LISSCommissioner

August 4,2000

RE: BOURNE--BWSC-4-0037Massachusetts MilitaryReservation, FTA-2/LF-2,PFSA/FS-10/FS-ll, SD-2/FS-6/FS-8, SD-3/FTA-3/CY-4, SD-4, andSD-5/FS-5, Explanation ofSignificant Differences, Comments

Dear Mr. Gill:

The Department of Environmental Protection (the "Department") has received adocument titled " Explanation of Significant Differences to the Final Record of Decision,Areas of Contamination FTA-2/LF-2, PFSA/FS-10/FS-ll, SD-2/FS-6/FS-8, SD-3/FTA-3/CY-4, SD-4, and SD-5/FS-5 Source Areas" (the "ESD") dated July 2000 and prepared for theAFCEE.

The Department finds the ESD acceptable.

Please incorporate this letter into the Administrative Record for Areas of ContaminationFTA-2/LF-2, PFSA/FS-10/FS-ll, SD-2/FS-6/FS-8, SD-3/FTA-3/CY-4, SD-4, and SD-5/FS-5. Ifyou have any questions regarding this matter, please contact me at (508) 946-2871 or Henry Cui at(508) 946-2889.

Very truly yours,

Leonard J. Pinaud, ChiefFederal Facilities Remediation Section

P/HCC\ESD.doc

This information is available in alternate format by calling our ADA Coordinator at (617) 574-6872.

DEP on the World Wide Web: http://www.magnet.state.ma.us/dep•JJ Printed on Recycled Paper

cc: DEP-SEROATTN: Paul A. Taurasi, P.E., Regional Director

Mildred Garcia-Surette, Deputy Regional Director

Distributions: SERO8MBPlume Containment TeamPublic Information TeamLong Range Water Supply PATBoards of SelectmenBoards of Health

Page 2

UNITED STATES ENVIRONMENTAL PROTECTION AGENCYREGION 1

1 CONGRESS STREET, SUITE 1100BOSTON. MASSACHUSETTS 02114-2023

August 4, 2000

Mr. Robert M. GillRemediation Program ManagerHQ AFCEE/MMR322 East Inner Road, Box 41Otis ANG Base, MA 02542-5028

Re: Draft Explanation of Significant Differences to the Final Record of DecisionAreas of Contamination FTA-2/LF-2, PFSA/FS-10/FS-l 1, SD-2/FS-6/FS-8,SD-3/FTA-3/CY-4, SD-4, and SD-5/FS-5 Source Areas (September, 1998)

Dear Mr. Gill:

This office is in receipt of the subject document, dated July 2000. Based upon our review, EPAhas the comments that are attached to this letter. EPA anticipates that these comments can beresolved quickly in order for this document to be finalized for the public comment periodcurrently scheduled for late August 2000 .

Should you have any questions on this matter, please contact me at (617) 918-1388 or MichaelJasinski at (617) 918-1352.

Sincerely,

Paul N. MflfcHessault, Remedial Project Managerederal Facilities Superfund Section

cc. MiJcrMinior, AFCEE-MMRLen Pinaud/Henry Cui, MA DEP-SERO

"Tarter Fahy, UnitechMike Jasinski, EPABetsy Mason, EPA

Tod Free •1-888-372-7341Internet Address (URL) • http://www.epa.gov/region1

RecyctodfffecycUbl* .Printed with Vegetable O« BMed Ink* on Recycled Piper (Minimum 30% Po*tcorwum«r)

EPA Comments on July 2000 document entitled:Draft Explanation of Significant Differences to the Final Record of DecisionAreas of Contamination FTA-2/LF-2. PFSA/FS-10/FS-11. SD-2/FS-6/FS-8.SD-3/FTA-3/CY-4. SD-4. and SD-5/FS-5 Source Areas fSeptember. 1998)

GENERAL COMMENTS

1. Table of Contents and Text: In accordance with EPA's Guide to Preparing SuperfundProposed Plans, Records of Decision, and Other Remedy Selection Documents., datedJuly 1999, the Explanation of Significant Differences (ESD) should contain threeadditional sections: Support Agency Comments, Statutory Determinations, and PublicParticipation Compliance. EPA requests that the language proposed by AFCEE forinclusion in the Final ESD for these three additional sections be provided for review aspart of the response to comments.

2. Throughout the ESD, replace "6 AOC's ROD" with "6 AOC ROD."

3. The Final ESD, following the scheduled 30-day public comment period, will requireindividual signature lines for the AFCEE Director and EPA's Director, Office of SiteRemediation and Restoration as was done for the Final 6 AOC ROD. The language thatshould be used for each signature should be as follows (similar in format to the FinalROD): "For the foregoing reasons, by my signature below, I concur and recommend theissuance of an Explanation of Significant Differences to the Final Record of Decision forAreas of Contamination FTA-2/LF-2, PFSA/FS-10/FS-l 1, SD-2/FS-6/FS-8, SD-3/FTA-3/CY-4, SD-4, and SD-5/FS-5 Source Areas (September, 1998) and the changes statedtherein." This signature page should be added to the current ESD and provided for reviewas part of the response to comments.

4. Upon finalization of this document, the date on the cover page should be changed toAugust 2000 (assuming all EPA and DEP comments are resolved and the document isready for public comment at the end of August 2000).

PAGE-SPECIFIC COMMENTS

Page ii. Abbreviations, Acronyms, and Initialisms

Remove the word "Initialisms" from the Title. PAH should read "polycyclic aromatichydrocarbons." USEPA - U.S. Environmental Protection Agency should be eliminated from thispage.

Introduction:

In the 1st sentence, delete the colon after "titled." In the 2nd sentence, replace "(EPA)" with"(EPA's)."

In the 2nd paragraph, 2nd sentence, replace "was in accordance" with "is in accordance," and addan "s" to "Documents" in the title of EPA's guidance.

In the 3rd paragraph: Replace "U.S. Environmental Protection Agency with "EPA," as EPA hasalready been abbreviated.

Page 2. Statement of Purpose:

In the 1st paragraph, 2nd sentence, replace "drafting a" with "preparing a draft." In the 3rd

sentence, replace "with CS-2," with "as part of CS-2,". In the 4th sentence, remove the word"necessary". In the 5th sentence, replace "this site" with "this study area".

In the 2nd paragraph, revise the 1st sentence to read "In essence, this ESD to the 6 AOC RODremoves the CS-2 drainage swale from CS-2 Study Area and adds it to AOC SD-5." In the 2nd

sentence, insert "6 AOC" before "ROD," and replace "National Contingency Plan" with "NCP."

Page 3. Site History/Contamination:

In the 1st paragraph, replace "Massachusetts Military Reservation" with "MMR."

In the 2nd paragraph, 1st sentence, delete "such as the Plume Response Plan." In the 2nd sentence,replace "this Record of Decision" with "the 6 AOC ROD."

In the 3rd paragraph, l$t sentence, insert "that had been considered part of the CS-2 Study Area"before "to the horizontal footprint."

Page 3. Section 3.1.1: In the 1st paragraph, add a sentence which indicates that more detailedinformation about AOC SD-5 can be found in the RI, FS and 6 AOC ROD, which can be found inthe Administrative Record. Also, in the 1st sentence, insert ", known as the Central DrainageSwale," after "storm drainage swale."

Page 4. Bullets: The current list ends at the Feasibility Study in 1997. The bullet chronologyshould be continued through the Proposed Plan, Public Comment Period and ROD signature.

Page 4. Seventh bullet: Spell out the meaning for the abbreviation "AVLUBE" since it is the firsttime used in the document.

Section 3.1.2: In the 2nd sentence, insert ", known as the Central Drainage Swale," after"natural drainage swale."

Page 5. Section 3.1.2:

In the 1st paragraph, is the drainage swale "along the western side of the AOC" the CentralDrainage Swale or the CS-2 drainage swale? Please identify it more clearly in the text andfigures.

In the 2nd paragraph, 1st sentence, make "central drainage swale" "Central Drainage Swale". Inthe 2nd sentence, capitalize "Stormwater Infiltration Basin".

In the 3rd paragraph before the bullets, insert "; see Figure 1" after "operable units (OUs)".

In the 4th paragraph, insert "in the 6 AOC ROD" after "CS-2 drainage swale," and insert "the"before "SD5A." Also, make "SD5A" into "SD-5A."

Page 6. Groundwater Contamination Assessment. In the 7th line, insert "their" before "respectiveMCLs". In the 10th line, insert "their" before "MCLs".

Page 6. Section 3.2: Change the heading to: "CS-2 Study Area".

Page 6. Section 3.2.1: The 1st sentence should be changed to: "The Chemical Spill No. 2 (CS-2)Study Area, located just west of the AOC SD-5 (see Figure 3 (Appendix A)), ..." At the end ofthe 1st paragraph, add a sentence which indicates that more detailed information about the CS-2Study Area can be found in the draft Decision Document for that study area, which is alsocurrently available for public comment.

Page 7. Section 3.2.1: In the 1st paragraph, change the 1st sentence to read: "Since the CS-2drainage swale (which is to be re-designated as part of the AOC SD-5) is located on the ..." Theexisting 2nd sentence of the 1st paragraph should become the beginning a new 2nd paragraph.

Page 7. Section 3.2.1: In the existing 2nd paragraph, change "Block 2" to CS-2" at the beginningof the 1st sentence of the 1st line of the paragraph.

Page 7. Section 3.2.1: In the existing 3rd paragraph, add "CS-2" before "drainage swale" in the 1st

line. In the 3rd sentence, "Motor Pool" should be "motor pool". In the 4th sentence, add "CS-2"before "drainage swale". At the end of the existing 3rd paragraph, a sentence should be addedwhich calls out the fold-out figure in Appendix B which should show (using cross-hatching) thelocations where the DSRP cleanup efforts were conducted (see similar comment on fold-ourfigure noted below).

Page 7. Section 3.2.2: In the last sentence on the page, change "Block 2" to "CS-2".

Section 3.2.2: The text here should give a summary of the concentrations and/or rangesof concentrations for the contaminants of concern within the CS-2 drainage swale.

Page 8. Section 3.2.2, Surface Soil: In the 2 sentence, replace "CRQL's" with "CRQLs."

Page 9. Section 4, l" paragraph: In the last sentence, add "for AOC SD-5" after "selectedremedy".

Page 9. Section 4, 2nd paragraph: The header should read: "Soil Target Cleanup Levels(STCLs)."

Page 12. 3rd paragraph: In the 2nd sentence, delete "Institutional" before "controls," as fences arenot institutional controls.

Page 13: In the 1st sentence, replace "the Chemical Spill No. 2 Study Area (CS-2)" with "CS-2."In the 1st sentence, add "above STCLs which were similar to those found within AOC SD-5."after "soil contaminants". In the 2nd sentence, replace "the Storm Drainage Ditch No. 5 (SD-5)"with "SD-5." Add a period to the last sentence at the end of the Ist paragraph.

Page 14. 1st paragraph: The 2nd and 3rd lines should be changed to: "... previously considered partof the CS-2 Study Area. The type of contamination, volume ...". In the 4th line, delete "soil" after"swale". In the 5th line, add "AOC" before "SD-5.". In the 9th line, replace "ditch" with "swale".

Page 14. 2nd paragraph:

Add the following as a new first sentence: "In essence, the CS-2 drainage swale will become partof the SD-5C Operable Unit of AOC SD-5, and the remedy selected for AOC SD-5 in the 6 AOCROD will address the former CS-2 drainage swale as well as the rest of SD-5."

In the old 1st sentence, replace "met" with "meet." In the old 1st and 2nd sentences, replace"would" with "will." In the old 2nd sentence, replace "Record of Decision" with "6 AOC ROD."In the old 3rd sentence, add "CS-2" before "drainage swale". In the old 4th sentence, insert"former CS-2" before "drainage swale." In the sentence beginning "This additional work,"replace "Record of Decision" with "the 6 AOC ROD."

The sentence that begins: "In summary, the selected remedy ..." should become a separate, new3rd paragraph.

The last sentence should be elaborated upon and removed from this Section and placed in a newSection in accordance with the ESD guidance (see General Comments). In addition, remove theapostrophes from around '"modified remedy.'"

Figure 2: The title should read: "CS-2 Drainage Swale and AOC SD-5".

Figure 3: The title should read: "CS-2 Study Area and Stormwater Drainage System".

Figure 3: This figure needs to be modified to identify many of the landmarks that are called outunder Section 3.2.1 on Page 6, e.g. Blocks 2, 4, and 5, Building 3202, etc.

Fold out Figure entitled "Physical Features. Associated Sample Locations. ...": This figure needsto more clearly identify (with cross-hatching) the locations where the DSRP cleanup efforts wereconducted in contrast to the CS-2 drainage swale which was not addressed as part of the DSRP.

Figure entitled "CS-2 Study Area Soil Sample Locations": In the legend, note the date on whichthe bore holes were taken, i.e., "October 8, 1999".

Table entitled "Soil Sample Location Descriptions": Remove any and all information that doesNOT pertain to CS-2 from this table.

AFCEE's Response to EPA's 8/4/2000 Comments on July 2000 document entitled:Draft Explanation of Significant Differences to the Final Record of DecisionAreas of Contamination FTA-2/LF-2. PFSA/FS-10/FS-11. SD-2/FS-6/FS-8.SD-3/FTA-3/CY-4. SD-4. and SD-5/FS-5 Source Areas (September. 1998)

GENERAL COMMENTS

1. Table of Contents and Text: In accordance with EPA's Guide to Preparing Superfund Proposed Plans,Records of Decision, and Other Remedy Selection Documents, dated July 1999, the Explanation ofSignificant Differences (BSD) should contain three additional sections: Support Agency Comments,Statutory Determinations, and Public Participation Compliance. EPA requests that the language proposedby AFCEE for inclusion in the Final BSD for these three additional sections be provided for review as partof the response to comments.

Response to Comment: AFCEE agrees. Above comment has been incorporated in the draft ESD.

2. Throughout the ESD, replace "6 AOC's ROD" with "6 AOC ROD."


3. The Final ESD, following the scheduled 30-day public comment period, will require individual signaturelines for the AFCEE Director and EPA's Director, Office of Site Remediation and Restoration as wasdone for the Final 6 AOC ROD. The language that should be used for each signature should be as follows(similar in format to the Final ROD): "For the foregoing reasons, by my signature below, I concur andrecommend the issuance of an Explanation of Significant Differences to the Final Record of Decision forAreas of Contamination FTA-2/LF-2, PFSA/FS-10/FS-ll, SD-2/FS-6/FS-8, SD-3/FTA-3/CY-4, SD-4,and SD-5/FS-5 Source Areas (September, 1998) and the changes stated therein." This signature pageshould be added to the current ESD and provided for review as part of the response to comments.

Response to Comment: AFCEE agrees. Above comment has been incorporated in the draft ESD. A revised DraftESD is enclosed for your review.

4. Upon finalization of this document, the date on the cover page should be changed to August 2000(assuming all EPA and DEP comments are resolved and the document is ready for public comment at theend of August 2000).


PAGE-SPECIFIC COMMENTS

Page ii. Abbreviations, Acronyms, and Initialisms

Remove the word "Initialisms" from the Title. PAH should read "polycyclic aromatic hydrocarbons." USEPA -U.S. Environmental Protection Agency should be eliminated from this page.


Page 1. Introduction:

In the 1" sentence, delete the colon after "titled." In the 2nd sentence, replace "(EPA)" with "(EPA's)."

In the 2nd paragraph, 2nd sentence, replace "was in accordance" with "is in accordance," and add an "s" to"Documents" in the title of EPA's guidance.

In the 3rd paragraph: Replace "U.S. Environmental Protection Agency" with "EPA," as EPA has already beenabbreviated.

Response to Page 1 Comments: AFCEE agrees. Above comments have been incorporated in the draft BSD,

Page 2, Statement of Purpose:

In the 1" paragraph, 2nd sentence, replace "drafting a" with "preparing a draft." In the 3rf sentence, replace "withCS-2," with "as part of CS-2,". In the 4th sentence, remove the word "necessary". In the 5th sentence, replace "thissite" with "this study area".

In the 2nd paragraph, revise the 1st sentence to read "In essence, this ESD to the 6 AOC ROD removes the CS-2drainage swale from CS-2 Study Area and adds it to AOC SD-5." In the 2nd sentence, insert "6 AOC" before"ROD," and replace "National Contingency Plan" with "NCP."

Response to Paee 2 Comments: AFCEE agrees. Above comments have been incorporated in the draft ESD.

'Page 3. Site History/Contamination:

In the 1" paragraph, replace "Massachusetts Military Reservation" with "MMR."

In the 2nd paragraph, 1st sentence, delete "such as the Plume Response Plan." In the 2nd sentence, replace "thisRecord of Decision" with "the 6 AOC ROD."

In the 3rd paragraph, 1" sentence, insert "that had been considered part of the CS-2 Study Area" before "to thehorizontal footprint."

Section 3.1.1: In the 1" paragraph, add a sentence which indicates that more detailed information about AOC SD-5can be found in the RI, FS and 6 AOC ROD, which can be found in the Administrative Record. Also, in the 1*sentence, insert", known as the Central Drainage Swale," after "storm drainage swale."

Response to Page 3 Comments: AFCEE agrees. Above comments have been incorporated in the draft ESD.

Page 4. Bullets: The current list ends at the Feasibility Study in 1997. The bullet chronology should be continuedthrough the Proposed Plan, Public Comment Period and ROD signature.

Seventh bullet: Spell out the meaning for the abbreviation "AVLUBE" since it is the first time used in thedocument.

Section 3.1.2: In the 2nd sentence, insert ", known as the Central Drainage Swale," after "natural drainage swale."


Page5. Section 3.1.2:

In the 1* paragraph, is the drainage swale "along the western side of the AOC" the Central Drainage Swale or theCS-2 drainage swale? Please identify it more clearly in the text and figures.

In the 2nd paragraph, l" sentence, make "central drainage swale" "Central Drainage Swale". In the 2nd sentence,capitalize "Stormwater Infiltration Basin".

In the 3rd paragraph before the bullets, insert"; see Figure 1" after "operable units (OUs)".

In the 4th paragraph, insert "in the 6 AOC ROD" after "CS-2 drainage swale," and insert "the" before "SD5A."Also, make "SD5A" into "SD-5A."


Page 6. Groundwater Contamination Assessment. In the 7th line, insert "their" before "respective MCLs". In the10th line, insert "their" before "MCLs".

Section 3.2: Change the heading to: "CS-2 Study Area".

Section 3.2.1: The l" sentence should be changed to: "The Chemical Spill No. 2 (CS-2) Study Area, located justwest of the AOC SD-5 (see Figure 3 (Appendix A)),..." At the end of the 1st paragraph, add a sentence whichindicates that more detailed information about the CS-2 Study Area can be found in the draft Decision Documentfor that study area, which is also currently available for public comment.


Page 7. Section 3.2.1: In the 1st paragraph, change the 1st sentence to read: "Since the CS-2 drainage swale (whichis to be re-designated as part of the AOC SD-5) is located on the ..." The existing 2nd sentence of the 1st paragraphshould become the beginning a new 2nd paragraph.

Section 3.2.1: In the existing 2nd paragraph, change "Block 2" to CS-2" at the beginning of the 1* sentence of the1st line of the paragraph.

Section 3.2.1: In the existing 3rd paragraph, add "CS-2" before "drainage swale" in the lrt line. In the 3rd sentence,"Motor Pool" should be "motor pool". In the 4* sentence, add "CS-2" before "drainage swale". At the end of theexisting 3rd paragraph, a sentence should be added which calls out the fold-out figure in Appendix B which shouldshow (using cross-hatching) the locations where the DSRP cleanup efforts were conducted (see similar commenton fold-our figure noted below).

Section 3.2.2: In the last sentence on the page, change "Block 2" to "CS-2".

Response to Pane 7 Comments: Appendix B, has been revised to become Figure 4 of Appendix A. AFCEE agreeswith the remainder of EPA's page 7 comments and has incorporated them in the draft ESD.

Page 8. Section 3.2.2: The text here should give a summary of the concentrations and/or ranges of concentrationsfor the contaminants of concern within the CS-2 drainage swale.

Section 3.2.2, Surface Soil: In the 2nd sentence, replace "CRQL's" with "CRQLs."

Response to Page 8 Comments: Section 3.2.2 has been revised to simply list the anatytes that exceed EPAscreening criteria. AFCEE has added a separate Figure 4, Lab Data from the CS-2 Drainage Swale, whicheffectively captures the information requested by EPA.

Page 9. Section 4, lrt paragraph: In the last sentence, add "for AOC SD-5" after "selected remedy".

Section 4, 2nd paragraph: The header should read: "Soil Target Cleanup Levels (STCLs)."

Response to Page 9 Comments: AFCEE agrees. Above comment has been incorporated in the draft ESD.

3rd paragraph: In the 2nd sentence, delete "Institutional" before "controls," as fences are not institutionalcontrols.

Response to Page 12 Comments: AFCEE agrees. Above comment has been incorporated in the draft BSD.

Page 13: In the 1* sentence, replace "the Chemical Spill No. 2 Study Area (CS-2)" with "CS-2." In the l"sentence, add "above STCLs which were similar to those found within AOC SD-5." after "soil contaminants". Inthe 2nd sentence, replace "the Storm Drainage Ditch No. 5 (SD-5)" with "SD-5." Add a period to the last sentenceat the end of the l" paragraph.


Page 14. l" paragraph: The 2nd and 3rd lines should be changed to: "... previously considered part of the CS-2Study Area. The type of contamination, volume ...". In the 4th line, delete "soil" after "swale". In the 5th line, add"AOC" before "SD-5.". In the 9th line, replace "ditch" with "swale".

2nd paragraph: Add the following as a new first sentence: "In essence, the CS-2 drainage swale will become part ofthe SD-5C Operable Unit of AOC SD-5, and the remedy selected for AOC SD-5 in the 6 AOC ROD will addressthe former CS-2 drainage swale as well as the rest of SD-5."

In the old 1st sentence, replace "met" with "meet." In the old 1" and 2nd sentences, replace "would" with "will." Inthe old 2nd sentence, replace "Record of Decision" with "6 AOC ROD." In the old 3rd sentence, add "CS-2" before"drainage swale". In the old 4th sentence, insert "former CS-2" before "drainage swale." In the sentencebeginning "This additional work," replace "Record of Decision" with "the 6 AOC ROD."

The sentence that begins: "In summary, the selected remedy ..." should become a separate, new 3rd paragraph.

The last sentence should be elaborated upon and removed from this Section and placed in a new Section inaccordance with the ESD guidance (see General Comments). In addition, remove the apostrophes from around"'modified remedy.'"


Figure 2: The title should read: "CS-2 Drainage Swale and AOC SD-5".

Figure 3: The title should read: "CS-2 Study Area and Stormwater Drainage System".

Figure 3: This figure needs to be modified to identify many of the landmarks that are called out under Section 3.2.1on Page 6, e.g. Blocks 2, 4, and 5, Building 3202, etc.

Fold out Figure entitled "Physical Features. Associated Sample Locations....": This figure needs to more clearlyidentify (with cross-hatching) the locations where the DSRP cleanup efforts were conducted in contrast to the CS-2drainage swale which was not addressed as part of the DSRP.

Figure entitled "CS-2 Study Area Soil Sample Locations": In the legend, note the date on which the bore holeswere taken, i.e., "October 8, 1999".

Table entitled "Soil Sample Location Descriptions": Remove any and all information that does NOT pertain to CS-2 fromthis table.

Response to Figure Comments: Lab Data Figures/Tables: See AFCEE's response to EPA's Page 7 and 8 commentsregarding a new Figure 4. The remainder of EPA's comments will be incorporated into the draft ESD.

APPENDIX CPUBLIC PARTICIPATION COMPLIANCE

A public comment period for this ESD took place from August 28, 2000 to September 26,2000. The newsrelease publishing this public comment period is attached. No comments were received. In advance of thiscomment period, a presentation concerning this ESD was held at the Joint Process Action Team (JPAT) onAugust 23, 2000.

MASSACHUSETTSMILITARY RESERVATION

Installation RestorationProgram

AFCEE/MMR/IRP Public Affairs322 East Inner RoadOtis Air National Guard Base, MA 02542-5028

CONTACT: Mr. Douglas C. Karson(508) 968-4679 ext. 2

FOR IMMEDIATE RELEASE

NEWS RELEASE 2000-XXAnnnctYYMugusi AA,

Public Comment Period Planned on Record of Decision(ROD) Addendum for Areas of Concern (AOCs)MASSACHUSETTS MILITARY RESERVATION, Cape Cod, Mass. — The Air Force Center forEnvironmental Excellence (AFCEE) will hold an informal 30-day public comment period on Record ofDecision (ROD) addendum titled, "Explanation of Significant Differences to the Final Record of Decision "The study areas covered under this document are Fire Training Area-2 (FTA-2)/Landfill-2 (LF-2), PetroleumFuel Storage Area (PFSA)/Fuel Spill-10 (FS-10)/Fuel Spill-1 1 (FS-11), Storm Drain-2 (SD-2)/Fuel Spill-6 (FS-6)/Fuel Spill-8 (FS-8), Storm Dram-3 (SD-3)/Fire Training Area-3 (FTA-3)/Coal Yard-4 (CY-4), Storm Drain-4(SD-4), and Storm Drain-5 (SD-5)/Fuel Spill-5 (FS-5). The Explanation of Significant Differences amends theRecord of Decision that was signed in September 1 998 to include a 1 50-foot drainage swale to the SD-5 studyarea.

After receiving analytical results on soil samples collected during a 1999 sampling event, AFCEE noted that thedrainage swale at CS-2 still contained elevated levels of soil contaminants. The drainage swale, originallyidentified with CS-2, was also within the footprint of the Storm Drain-5 (SD-5) study area. Since the SD-5study area was already scheduled for remedial activities in 2000 under the current ROD, AFCEE determined itwas more practical and expeditious to add the CS-2 drainage swale to the SD-5 study area, and remove it fromthe original definition of the CS-2 study area. Both the United States Environmental Protection Agency (EPA)and the Massachusetts Department of Environmental Protection (DEP) concur with this decision.The informal 30-day comment period begins August 28, 2000 and ends September 26, 2000.

Copies of the Explanation of Significant Differences to the Final Record of Decision (Areas of Concern: FTA-2/LF-2, PFSA/FS-10/FS-l 1, SD-2/FS-6/FS-8, SD-3/FTA-3/CY-4, SD-4, and SD-5/FS-5) will be available forreview during the public comment period at the main libraries in Bourne, Mashpee and Falmouth, and at the USCoast Guard library on the base, as well as at the Installation Restoration Program Office and on its web site atwww.mmr.org.

Written comments may be submitted by mail to:

By fax to:By electronic mail to:By internet to:

HQ AFCEE/MMRAttn: BSD AOCs322 East Inner RoadOtis ANG Base, MA 02542-5028(508) [email protected]://www.mmr.org

For additional information, please call Doug Karson, AFCEE Community Involvement Specialist, at 508-968-4678 x2

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