EAST-SIDE AQUIFER TREATMENT SYSTEM (OPERABLE UNIT 5) … · The remedy at Operable Unit 5 includes...

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Base Realignment and ClosureProgram Management Office West1230 Columbia Street, Suite 1100

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FINAL

EAST-SIDE AQUIFER TREATMENT SYSTEM(OPERABLE UNIT 5)

FIVE-YEAR REVIEW REPORT FOR THE PERIODJANUARY 1999 TO DECEMBER 2002

February 2005

FORMER NAVAL AIR STATION MOFFETT FIELDMOFFETT FIELD, CALIFORNIA

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FINAL

EAST-SIDE AQUIFER TREATMENT SYSTEM(OPERABLE UNIT 5)


FORMER NAVAL AIM STATION MOFFETT FIELDMOFFETT FIELD, CALIFORNIA

(Pursuant to the Comprehensive EnvironmentalResponse, Compensation, and Liability Act)

February 2005

ISSUED BY:

U.S. DEPARTMENT OF THE NAVYBASE REALIGNMENT AND CLOSURE (BRAC)

PROGRAM MANAGEMENT OFFICE WEST

TABLE OF CONTENTS

PAGE

LIST OF TABLES , .,_........... ... iii

LIST OF FIGURES ............JW_ iii

ABBREVIATIONS AND ACRONYMS.,, v

DECLARATION OF ACCEPTANCE FOR EAST-SIDE AQUIFER TREATMENTSYSTEM (OPERABLE UNIT 5) FIVE-YEAR REVIEW REPORT FOR THE PERIODJANUARY 1999 TO DECEMBER 2002 FORMER NAVAL AIR STATIONMOFFETT FIELD, MOFFETT FIELD, CALIFORNIA DA-1

EXECUTIVE SUMMARY ...„_,..„....... ES-1

FIVE-YEAR REVIEW SUMMARY FORM SF-1

1.0 INTRODUCTION ,,,,™IMI, ,.. 1-11.1 PURPOSE „,,_,_..,.,.......... 1-21.2 DOCUMENT ORGANIZATION , , 1-2

2.0 OPERABLE UNIT 5 CHRONQLODY..;........... 2-1

3.0 BACKGROUND ,..„_„„,,„...,,......... 3-13.1 SITE TOPOGRAPHY ..,„„,„.„... „ 3-13.2 GEOLOGY ..„.„,,,. 3-13.3 HYDROGEOLOGY.. 3-13.4 LAND AND RESOURCE USE 3-23.5 HISTORY OF CONTAMINATION... 3-23.6 INITIAL RESPONSE/BASIS FOR TAKING ACTION 3-4

4.0 REMEDIAL ACTIONS ,._,_........ 4-14.1 REMEDY SELECTION...^.... 4-14.2 REMEDY IMPLEMENTATION 4-1

4.2.1 EATS Extraction 4-24.2.2 Institutional and Engineering Controls 4-24.2.3 Groundwater Monitoring ...4-3

4.3 EATS TREATMENT PERFORMANCE 4-34.4 OPERATION AND MAINTENANCE 4-5

4.4.1 VOC Emission Monitoring—Air Stripper , 4-54.4.2 Operation and Maintenance Costs 4-6

4.5 ENFORCEMENT ACTIONS;.T ........,.. 4-6

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TABLE OF CONTENTS(Continued)

PAGE

5.0 FIVE-YEAR REVIEW PROCESS ........... . ....................................................................... 5-15.1 ADMINISTRATIVE COMPONENTS ............ ...................................................... 5-1

5.1.1 Notification of Potentially Interested Parties of Initiation ofReview Process .................... ...................................................................... 5-1

5. 1. 2 Identification of Five-Year Review Team ................................................. 5-15.1.3 Outline of Components and Five-Year Review Schedule ......................... 5-1

5.2 CQMMUNITY INVOLVEMENT ......................................................................... 5-25.3 DOCUMENT REVIEW ............................. , ........................................................... 5-25.4 DATA REVIEW ....... , ............................................................................................. 5-25.5 SITE INSPECTION ...................... . ......................................................................... 5-55.6 INTERVIEWS ........................................................................................................ 5-55.7 SUMMARY OF EATS EVALUATION WORK PLAN ....................................... 5-5

6.0 TECHNICAL ASSESSMENT .......................................................................................... 6-16. 1 QUESTION A: IS THE REMEDY FUNCTIONING AS INTENDED

BY THE DECISION DOCUMENTS? ................................................................... 6-16.2 QUESTION B: ARE THE EXPOSURE ASSUMPTIONS, TOXICITY DATA,

CLEANUP LEVELS, AND REMEDIAL ACTION OBJECTIVES USEDAT THE TIME OF THE REMEDY SELECTION STILL VALID? ..................... 6-2

6.3 QUESTION C: HAS ANY OTHER INFORMATION COME TO LIGHTTHAT COULD CALL INTO QUESTION THE PROTECTIVENESSOF THE REMEDY? ............................................................................................... 6-3

6.4 TECHNICAL ASSESSMENT SUMMARY .......................................................... 6-3

7.0 ISSUES.. ............................................................................................................................ 7-1

8.0 RECOMMENDATIONS AND FOLLOW-UP ACTIONS .............................................. 8-1

9.0 PROTECTIVENESS STATEMENT ................................................................................ 9-1

10.0 NEXT REVIEW .............................................................................................................. 10-1

11.0 REFERENCES ................................................................. , .............................................. 11-1

APPENDICES

Appendix A Document Review List

Appendix B Five-Year Review Inspection Form

Appendix C Operable Unit 5 Photographs

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LIST OF TABLES

Table 2-1

Table 3-1

Table 3-2

Table 4-1

Table 4-2

Chronology of Operable Unit 5

Hydrostratigraphy

Comparison of 1,1-DCE, 1,2-DCA, cis-l,2-DCE, PCE, TCE and VCConcentrations - Baseline Year (1998) vs. 2002

EATS Annual Operational Data

EATS Annual System O&M Costs

Figure 1-1

Figure 1-2

Figure 3-1

Figure 3-2

Figure 3-3

Figure 3-4

Figure 3-5

Figure 3-6

Figure 3-7

Figure 3-8

Figure 3-9

Figure 4-1

Figure 4-2

Figure 4-3

LIST OF FIGURES

Regional Location Map

Site Location Map

EATS Location and Approximate Extent of VOC Plumes in 1996

EATS Location and Approximate Extent of VOC Plumes in 2002

Location of EATS Extraction Wells and Monitoring Wells

Time Series of TCE Concentrations

Time Series of PCE Concentrations

Time Series of cis-l,2-DCE Concentrations

Time Series of Vinyl Chloride Concentrations

Time Series of 1,1-DCE Concentrations

Time Series of 1,2-DCA Concentrations

EATS Process Flow Diagram

EATS Cumulative Contaminant Mass Removed andCumulative Volume of Water Treated

EATS Contaminant Removal Rate Cost

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ABBREVIATIONS AND ACRONYMS

ARARs

BAAQMD

BCT

bgs

BRAG

CERCLA

CFR

cis-l,2-DCE

COC

CTR

1,2-DCA

1,1 -DCE

DoD

DoN

DISC

EATS

EPA

BSD

FS

ft

ft/day

ft/ft

FWENC

GAC

gpm

IAS

IR

applicable or relevant and appropriate requirements

Bay Area Air Quality Management District

BRAC Cleanup Team

below ground surface

Base Realignment and Closure

Comprehensive Environmental Response, Compensation, and Liability Act

Code of Federal Regulations

cis-1,2-dichloroethene

chemical of concern

California Toxics Rule

1,2-dichloroethane

1,1-dichloroethene

Department of Defense

Department of the Navy

(California) Department of Toxic Substances Control

East-Side Aquifer Treatment System

U.S. Environmental Protection Agency

Explanation of Significant Differences

Feasibility Study

feet ;

feet per day

foot per foot

Foster Wheeler Environmental Corporation

granular activated carbon

gallons per minute

Initial Assessment Study

Installation Restoration

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Ib

MCL

mg/L

MNA

MOA

msl

NAS

NASA

NE

NPDES

NPL

O&M

OU

PCE

PRC

RAB

RI

ROD

RWQCB

SWRCB

TCE

IDS

TtEMI

TtFW

USN

UST

ABBREVIATIONS AND ACRONYMS(Continued)

pound

maximum contaminant level

micrograms per liter

milligrams per liter

monitored natural attenuation

Memorandum of Agreement

mean sea level

Naval Air Station

National Aeronautics and Space Administration

nutrient enhancement

National Pollutant Discharge Elimination System

National Priority List

operation and maintenance

operable unit

tetrachloroethene (also known as perchloroethene)

PRC Environmental Management, Inc.

Restoration Advisory Board

Remedial Investigation

Record of Decision

Regional Water Quality Control Board

State Water Resources Control Board

trichloroethene

total dissolved solids

Terra Tech EM, Inc.

Tetra Tech FW, Inc.

United States Navy

underground storage tank

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ABBREVIATIONS AND ACRONYMS(Continued)

VC vinyl chloride

VOC volatile organic compound

WATS West-Side Aquifers Treatment System

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DECLARATION OF ACCEPTANCE FOREAST-SIDE AQUIFER TREATMENT SYSTEM (OPERABLE UNIT 5)


FORMER NAVAL AIR STATION MOFFETT FIELD,MOFFETT FIELD, CALIFORNIA

Pursuant to the delegations of authority in Sections 2(d) and ll(g) of Executive Order 12580,and U.S. Department of Defense (DoD) Instruction 4715.7 of 22 April 1996, the Department ofthe Navy (DoN) is the approval authority for Comprehensive Environmental Response,Compensation, and Liability Act (CERCLA) five-year reviews conducted at sites under itsjurisdiction, custody, or control.

ANNKLIMEK DateACTING BASE CLOSURE MANAGERBRAC PROGRAM MANAGEMENT OFFICE WEST

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EXECUTIVE SUMMARY

This report presents the five-year review of the remedy implemented at the East-Side AquiferTreatment System (EATS) (Operable Unit [OU] 5), at the former Naval Air Station (NAS)Moffett Field (Moffett), near Mountain View, California. This review was conducted by theDepartment of the Navy (DoN) in accordance with the Comprehensive Environmental Response,Compensation, and Liability Act (CERCLA) and Executive Order 12580.

The purpose of this five-year review is to evaluate the implementation and performance ofEATS, including assessing whether the selected remedy remains protective of human health andthe environment. This is the first five-year review for EATS (OU 5).

Groundwater in OU 5 is divided into a southern and northern plume in the Record of Decision(ROD). EATS is a groundwater remediation system located on the east side of the runways,northeast of Hangar 3, which was installed to clean up volatile organic compounds (VOCs) in thesouthern plume. Trichloroethene (TCE) and tetrachloroethene (PCE) are believed to have beenused at Hangars 2 and 3. Groundwater samples collected from the southern plume at OU 5 showthat the VOCs detected at the highest concentrations were TCE and PCE. During November2002 groundwater sampling, TCE was detected in the southern plume at a maximumconcentration of 51 micrograms per liter (|ag/L). The highest concentration of PCE detected inEATS groundwater monitoring wells during November 2002 sampling was 44 jag/L. There areno buildings over the plume.

Groundwater flow in the area of the QU 5 southern plume is to the north, toward the northernplume. Groundwater monitoring is the only action required by the ROD for the northern plumebecause the groundwater does not satisfy the criteria for a potential drinking water source andposes no unacceptable risk to human health or the environment. There are no buildings in thisarea. In November 2002, TCE was detected at a concentration of 14 |ag/L in one northern plumewell. TCE was either not detected or not detected above an estimated (J qualified) concentrationof 2J [igfL in other northern plume wells. PCE was not detected in November 2002 in thenorthern plume wells (detection limit of 2 p.g/L).

Assessment in this five-year review indicates that the remedy was constructed in accordancewith the requirements of the ROD. The maximum concentrations of the chemicals of concern(COCs) have slightly decreased or remained the same. EATS may not be efficient in cleaning upthe low concentrations of VOCs (maximum TCE concentration of 5 1 )ag/L) in the groundwater.Due to the low concentrations of extracted contaminants and low mass removal rates,opportunity exists to optimize and/or select more effective and economical remedies throughimplementation of the EATS Evaluation Work Plan. Prior to issuance of this five-year reviewreport, the EATS Evaluation Work Plan was issued and implementation of activities described

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therein began. The recommendation of this five-year review report is to complete theimplementation of the EATS Evaluation Work Plan in order to collect field data for evaluation ofthe effectiveness iand efficiency of EATS and applicability of other potential remedial options inachieving the groundwater standards specified in the ROD.

The remedy at Operable Unit 5 includes extraction and treatment of the southern plumegroundwater by the East-Side Aquifer Treatment System, groundwater monitoring, andinstitutional controls. The remedy at Operable Unit 5 is currently protective of human health andthe environment; because there is no evidence of current or potential exposure. During theimplementation c^f the remedy, exposure pathways that could result in unacceptable risk arebeing controlled.' In order for the remedy to remain protective until cleanup levels are met,institutional confrol restrictions preventing exposure to, or ingestion of, contaminatedgroundwater must remain in place. Long-term protectiveness of human health and theenvironment is expected to be achieved upon attainment of groundwater cleanup goals specifiedin the Record of Decision.

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FIVE-YEAR REVIEW SUMMARY FORM

SITE IDENTIFICATION

Site name (from WasteLAN) former Naval Air Station Moffett Field, East-Side Aquifer Treatment

System, Operable Unit 5

EPA ID (from WasteLAN) CA2170090078

Region: 09 State: CA City/County: Moffett Field / Santa Clara County

SITE STATUSi ^^^^^

NPL status: $3 Final D Deleted Q Other (specify)

Remediation status (choose all that apply): Q Under Construction £3 Operating D Complete

Multiple OUs? IEI YES D NO Construction completion date: 01 / 26 / 99

Has site been put into reuse? D YES NO

REVIEW STATUS

Reviewing agency: £3 EPA ^ State p Tribe [>3 Other Federal Agency US Navy

Author name: Andrea Espinoza

Author Title: BRAC EnvironmentalCoordinator

Author affiliation: Base Realignment and ClosureProgram Management Office West

Review period: 01 / 1999 to 12 / 2002

Date(s) of inspection: 08 / 06 / 2002

Type of review: d Statutory

El Policy Post-SARA D Pre-SARA D NPL-Removal only

Non-NPL Remedial Action Site D NPL State/Tribe-lead

Regional Discretion)

Review number: El 1 (first) D 2 (second) D 3 (third) D Other (specify)

Triggering action:

D Actual RA Onsite Construction at OU D Actual RA Start at OU #

] Construction Completion D Previous OU1 2002 Five-Year Review Report

D Other (specify)

Triggering action date (from WasteLAN): 01 / 26 / 1999

Due date (five years after triggering action date): 01 / 26 / 2004

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FIVE-YEAR REVIEW SUMMARY FORM(Continued)

Issues:;

• The E-ast-Side Aquifer Treatment System (EATS) may not be efficient in cleaning upthe low concentrations of volatile organic compounds (VOCs) in the groundwater.

Recommendations and Follow-up Actions:• Complete implementation of the EATS Evaluation Work Plan to collect field data for

the evaluation of the effectiveness and efficiency of EATS and applicability of otherpotential remedial options in achieving the groundwater cleanup standards specifiedin the| Record of Decision. Due to the low concentrations of extracted contaminantsand l<pw mass removal rates, opportunity exists to optimize and/or select moreeffective and economical remedies through implementation of the EATS EvaluationWork Nan.

Protectiveness Statement(s):The remedy at Operable Unit 5 includes extraction and treatment of the southern plumegroundwater by! the East-Side Aquifer Treatment System, groundwater monitoring, andinstitutional controls. The remedy at Operable Unit 5 is currently protective of human health andthe environment I because there is no evidence of current or potential exposure. During theimplementation qf the remedy, exposure pathways that could result in unacceptable risk arebeing controlled.; In order for the remedy to remain protective until cleanup levels are met,institutional control restrictions preventing exposure to, or ingestion of, contaminatedgroundwater must remain in place. Long-term protective ness of human health and theenvironment is expected to be achieved upon attainment of groundwater cleanup goalsspecified in the Record of Decision.

Other Comments:

• None.

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1.0 INTRODUCTION

The Department of the Navy (DoN) has conducted a five-year review of the remedial actionsimplemented at the East-Side Aquifer Treatment System (EATS) in accordance with the Recordof Decision (ROD) issued for Operable Unit (OU) 5. EATS is located on former Naval AirStation (NAS) Moffett Field (Moffett), near Mountain View, California (Figures 1-1 and 1-2).

This five-year review was conducted in accordance with DoN and U.S. EnvironmentalProtection Agency (EPA) guidance documents (DoN, 200la; EPA, 2001), for the review periodJanuary 1999 to December 2002. This five-year review work was initiated in May 2002. DoN isresponsible for conducting this five-year review of the remedy implemented at OU 5. DoN hasprepared this five-year review report pursuant to the Comprehensive Environmental Response,Compensation, and Liability Act (CERCLA) and Executive Order 12580.

This is the first five-year review for EATS (OU 5). The triggering action for this review is thecompletion of the remedial action construction on January 26, 1999. Prior to issuance of thisfive-year review report, the EATS Evaluation Work Plan was issued and implementation ofactivities described therein began.

Groundwater in OU 5 is divided into j^southem and northern plume in the ROD. EATS is agroundwater remediation system located on the east side of the runways, northeast of Hangar 3,which was installed to clean up volatile organic compounds (VOCs) in the southern plume.Sections 3.0 and 4.0 discuss background data and the remedy. This remedial action, uponcompletion, will not leave hazardous substances, pollutants, or contaminants on site above levelsthat allow for unlimited use and imrejtricted exposure, but requires five years or more tocomplete (DoN, 1996; EPA, 2001). Groundwater monitoring is the only action required by theROD for the northern plume because the groundwater does not satisfy the criteria for a potentialdrinking water source and poses no unacceptable risk to human health or the environment (DoN,1996).

Currently, there are two operable units at Moffett, OU 1 and OU 5. The Final Operable Unit 12002 Five-Year Review Report was signed and issued in September 2002. That was the firstfive-year review report for OU 1, which consists of the Site 1 Landfill and the former Site 2Landfill. The five-year review for OU 1 documented the ROD-specified consolidation of Site 2into Site 1 and that the Site 1 cap is functioning as designed and is currently protective of humanhealth and the environment. It stated that concentrations of chemicals of concern (COCs) ingroundwater samples collected to date have been low. Following development of groundwaterconcentration limits for Site 1, the DoN will issue an addendum to the five-year review report. InDecember 2002, in addition to the two operable units, OU 1 and OU 5, there were four otheractive installation restoration (IR) sites at Moffett, Sites 22, 25, 27, and West-Side Aquifers

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Treatment System (WATS) (Figure 1-2). At Site 22, a landfill underlying a portion of the golfcourse, the Remedial Action Work Plan for the biotic barrier was finalized in December 2002. AtSite 25, a wetland site contaminated by stormwater runoff, and Site 27, the Northern Channel,data were being evaluated during the review period for the EATS Five-Year Review Report toassess the appropriate action. At WATS, a site where solvents have contaminated thegroundwater, the remedy, a pump and treat system, is in place and functioning as designed (TetraTech EM, Inc. [TtEMI], 2001a). A five-year review report is also being prepared for the West-Side Aquifers Treatment System, which treats part of the Middlefield-Ellis-Whisman RegionalPlume.

1.1 PURPOSE

The purpose of this five-year review is to evaluate the implementation and performance ofEATS, including 'assessing whether the selected remedy remains protective of human health andthe environment, i The methods, findings, and conclusions of reviews are documented in thisreport. In addition, this report presents issues identified during the review and recommendationsto address those issues (Sections 7.0 and 8.0).

1.2 DOCUMENT ORGANIZATION

This report is organized as follows:

• Section 1.0—Provides the purpose of the five-year review, the agency conducting thefive-yqar review, when the review was initiated and completed, the review number,the trigger date, the status of other five-year reviews, and the organization for thefive-year review document.

• Sectio^ 2.0—Describes the site chronology.

• Section 3.0—Describes the background of the site, including site topography,geology, hydrogeology, land and resource use, history of contamination, and initialresponse/basis for taking action.

• Sectioiji 4.0—Describes the remedial actions conducted at the site, including remedyselection, remedy implementation, EATS treatment performance, and operation andmaintenance.

• Section 5.0—Describes the five-year review process, including administrativecomponents, community involvement, document and data review, and site inspection.

• Sectioif 6.0—Presents the technical assessments of the remedy.

• Section 7.0—Presents issues identified during the technical assessment.

• Section 8.0—Presents recommendations and follow-up actions.

• Section 9.0—Provides the protectiveness statement.

• Section 10.0—Proposes the date for the next review.

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• Section 11.0—Provides the referenced documents used for this report.

• Appendix A—Contains the document review list used for research while preparingthis report.

• Appendix B—Contains the five-year review inspection form.

• Appendix C—Contains the photographs of EATS.

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2.0 OPERABLE UNIT 5 CHRONOLOGY

The chronology for OU 5 is presented in Table 2-1. EATS construction began in July 1997, andoperation began in January 1999. Groundwater extraction, treatment, and groundwatermonitoring were ongoing throughout the review period for this five-year review report.

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3.0 BACKGROUND

The following sections describe the site conditions, land and resource use, a brief history ofcontamination, and initial response and summary of the basis for taking action.

3.1 SITE TOPOGRAPHY

The EATS area, located east of the Moffett runways, is generally flat. Moffett is relatively flat,ranging from 2 feet (ft) below to 36 ft above mean sea level (msl). A sizeable portion of Moffettis situated on previously submerged land or marshlands that have been filled to their existingelevations with backfill material. Wetlands located in the northern portion of Moffett are the onlynatural surface water. Surface drainage near Moffett includes Stevens Creek to the west andCoyote Creek and Guadalupe Slough to the east (Foster Wheeler Environmental Corporation,Inc. [FWENC], 2002).

3.2 GEOLOGY

Moffett is located at the northern end of the Santa Clara Valley Basin, approximately 1 milesouth of San Francisco Bay (see Figure 1-1). Regionally, the Santa Clara Valley containsinterbedded alluvial, fluvial, and estuarine deposits to a depth of as much as 1,500 ft belowground surface (ft bgs) (Iwamura, 1980). Locally, these sediments consist of varyingcombinations of clay, silt, sand, and gravel that represent the interfingering of estuarine andalluvial depositional environments during the late Pleistocene and Holocene epochs. The fluvialsediments were derived from the Santa Cruz highlands west of the basin and deposited on analluvial plain bounded by alluvial fan deposits to the west and baylands to the northeast(Iwamura, 1980). The heterogeneous nature of channel and interchannel sediments deposited inthe fluvial depositional environment is evident in the many subsurface explorations that havebeen conducted at Moffett. These sediments most likely were deposited during the Holoceneperiod when the worldwide sea level was rising toward its present elevation.

3.3 HYDROGEOLOGY

The subsurface sediments are divided into upper and lower aquifers. The upper aquifers areclassified as the A and B aquifers and have been further subdivided into aquifer zones.Continuous and semicontinuous aquitards divide the aquifers and aquifer zones. The aquifer andaquitard descriptions are based on lithologic interpretation of soil borings and cone penetrometertests (FWENC, 2002). The aquifer zones and aquitards applicable to EATS and theirapproximate depths are presented in Table 3-1.

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The groundwatej flow on the eastern side of Moffett is toward the bay (north), with a gradient ofabout 0.003 foot per foot (ft/ft). Therefore, groundwater flow in the area of the OU 5 southernplume is to the north, toward the northern plume. Porosity ranges from 20 to 45 percent (PRCEnvironmental Management, Inc. [PRC]), 1995). Hydraulic conductivity estimates range fromapproximately 30 to 150 feet per day (ft/day) (FWENC, 2003b). The annual average yields ofEATS extraction wells in the Al aquifer zone range from approximately 0.9 to 9.7 gallons perminute (gpm), with specific capacities ranging from approximately 2.2 to 18.4 gpm per ft ofdrawdown (FWENC, 2003b).

Water levels and groundwater flow in the Al aquifer zone are influenced locally by the EATSextraction wells. In addition, the Building 191 lift station and its associated drainage networkinfluence groundwater flow in the Al and A2 aquifer zones.

3.4 LAND AND RESOURCE USE

Land usage is specified in the Moffett Field Comprehensive Use Plan (National Aeronautics andSpace Administration [NASA], 1994). The area east of the runways includes two planning areas.One of the planning areas contains approximately 174 acres and is used for air operations. Theother planning area is approximately 248 acres and is used for ordnance storage facilities andfuel storage areas. NASA's Comprehensive Use Plan (NASA, 1994) restricts access anddevelopment in the OU 5 area because of safety considerations related to munitions storage andrunway/air operations and indicates no land use change is planned. The closest residential area isapproximately 1 mile southwest (upgradient from) OU 5 (DoN, 1996). Groundwater monitoringdata show that np buildings overlie the northern or southern OU 5 plumes (FWENC, 2003b).

Moffett is located in the South Bay Groundwater Basin. The Regional Water Quality ControlBoard (RWQCB) has determined that the criteria for drinking water sources are applicable toMoffett. The criteria are defined as groundwater with total dissolved solids (TDS) lower than3,000 milligrams per liter (mg/L) and that is capable of supporting a pumping yield of at least200 gallons per day (State Water Resources Control Board [SWRCB], 1998). Groundwater inthe OU 5 southern plume meets these criteria, so is considered a potential drinking water source.There are no drinking water wells in the OU 5 area. The groundwater would have to be treatedprior to any future use for drinking water supply because ambient concentrations of metals,which are naturally occurring, exceed drinking water standards (DoN, 1996). Because TDSlevels in groundwater within the Al aquifer zone at the northern end of Moffett, including thearea of the OU 5 northern plume, exceed the limit, groundwater in this area is not considered apossible drinking water source.

3.5 HISTORY OF CONTAMINATION

Contaminants identified during previous investigations included low concentrations of twoVOCs: trichloroethene (TCE) and tetrachloroethene (PCE). These two VOCs are reported to

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have been used at Hangars 2 and 3. They may have been discharged with wastewater to theformer flux ponds, which were located at the present EATS treatment pad, as well as to variousunderground storage tanks (USTs) on the eastern side of Moffett (TtEMI, 2001 a). Lowconcentrations of other VOCs, primarily cis-l,2-dichloroethene (cis-l,2-DCE) and vinyl chloride(VC), are found commingled with TCE and PCE, and are likely reductive dechlorinationproducts from natural degradation. The contamination was discovered during the 1984 InitialAssessment Study (IAS) and subsequent Confirmation Study.

VOCs in OU 5 are divided into southern and northern plumes (DoN, 1996). Figures 3-1 and 3-2show the approximate extent of the southern and northern VOC plumes in 1996 and 2002,respectively. Although there are differences in the boundaries of these plumes, the overall plumelocation and average concentrations are generally stable. Locations of EATS extraction andgroundwater monitoring wells are shown on Figure 3-3.

Groundwater samples collected from the southern plume at OU 5, which is being treated byEATS, show that the VOCs detected at the highest concentrations were TCE and PCE. DuringNovember 2002 groundwater sampling, TCE was detected in the southern plume at a maximumconcentration of 51 micrograms per liter (jj,g/L). The highest concentration of PCE detected inEATS groundwater monitoring wells during November 2002 sampling was 4.4 jag/L. The in situmass of the southern plume consists primarily of TCE and cis-l,2-DCE (FWENC, 2003b). Themaximum concentrations of 1,1-DCE, 1,2-DCA, cis-l,2-DCE, and VC detected in the November2002 sampling event were 0.8J ]_ig/L, 0.6 |ug/L, 19 [J.g/L, and 4 [J,g/L, respectively.

Table 3-2 compares 1998 (pre-EATS operation) and 2002 groundwater monitoring andextraction well concentrations for 1,1-DCE, 1,2-DCA, cis-l,2-DCE, PCE, TCE and VC. Ingeneral, concentrations have decreased slightly or have remained approximately the same.

Figures 3-4 through 3-9 provide concentration trend graphs vs. time for the chemicals of concern(COCs) specified in the ROD (TCE, PCE, cis-l,2-DCE, VC, 1,1-DCE, and 1,2-DCA) for thegroundwater monitoring and extraction wells listed on Table 3-2 and wells W3-1, WU5-1, W7-10, and WSW-5. These are the wells that were sampled both in 1998 and 2002 as well as thewells containing the maximum concentration of one of the COCs in 2002. On each of thesegraphs, a line is plotted showing the ROD cleanup standard (the maximum contaminant level[MCL]) for each COC.

Review of Table 3-2 and Figures 3-4 through 3-9 shows that COCs in many wells are currentlynot detected or detected at concentrations below the cleanup goal specified in the ROD (theMCL). Since 1998,1,1-DCE was seldom detected and concentrations in all wells were below theMCL. In 2002, 1,2-DCA was seldom detected, with a maximum concentration of 0.6 |j,g/L. VCwas not detected in samples from many wells in 2002, with a maximum concentration of 4 jag/L.

030945 Final EATS 5-Yr Rvw Rptdoc 3-3

In 2002, PCE was detected at a concentration above the MCL in samples from only twogroundwater monitoring wells, wells WU5-24 and W7-10.

iIsoconcentratiori maps for several of the compounds listed in Table 3-2 can be found in the FinalFirst Annual Groundwater Report for WATS and EATS (FWENC, 2002). Figures 3-23, 3-24, 3-27, 3-30, 3-33, and 3-36 show TCE concentration contours. Figures 3-39, 3-40, 3-43, 3-46, 3-49,and 3-52 are PCE isoconcentration maps. Vinyl chloride concentrations are shown on Figures3-55, 3-56, 3-59, 3-62, 3-65, and 3-68. Figures 3-71, 3-72, 3-75, 3-78, 3-81, and 3-84 are cis-1,2-DCE isoconcentration maps (FWENC, 2002). Figures 3-66 and 3-69 of the Final 2001 AnnualGroundwater Report for WATS and EATS (FWENC, 2003b) show TCE and cis-l,2-DCEconcentrations, respectively. TCE, cis-l,2-DCE, PCE, and VC concentrations are shown onFigures 3-31 through 3-34 of the 2002 Annual Groundwater Report for WATS and EATS (TetraTech FW, Inc. [TtFW], 2004).

The southern QU 5 cis-l,2-DCE plume is offset to the north and west of the TCE plume(FWENC, 2003b). Detections of PCE and other COCs are within the boundaries of the TCEplume and coincide with the higher TCE concentrations. Plume shape and averageconcentrations are stable (FWENC, 2003b).

In November 2002, TCE was detected at a concentration of 14 |ug/L in the sample from one OU5 northern plume well, WU5-4. TCE was either not detected or not detected above an estimated(J qualified) concentration of 2J u-g/L in samples from other northern plume wells. PCE, 1,1-DCE, 1,2-DCA and VC were not detected above their respective detection limits in November2002 in samples from the northern plume wells. Cis-l,2-DCE was either not detected or notdetected above an estimated concentration of 0.3 J ug/L in samples from northern plume wells.

3.6 INITIAL RESPONSE/BASIS FOR TAKING ACTION

The initial response at OU 5 included site characterization, which included the IAS in 1984, thesubsequent Confirmation Study, and remedial investigation. No CERCLA removal actions wereconducted. However, USTs containing petroleum hydrocarbons in the OU 5 area wereinvestigated and removed, as required.

OU 5 data collected since 1989 indicate that TCE, 1,2-DCE, PCE, 1,2-DCA, 1,1-DCE, and VCwere detected in OU 5 groundwater samples at maximum concentrations of 140, 90, 260, 14, 16,and 89 jag/L, respectively (DoN, 1996). The ROD specifies that the OU 5 medium isgroundwater, with only the OU 5 southern plume targeted for treatment. Since the OU 5 southernplume is in an area of potential drinking water use (Section 3.4), the ROD specifies extractionand treatment of groundwater, with MCLs as the cleanup goals. Groundwater monitoring datashow that no buildings overlie the northern or southern OU 5 plumes (FWENC, 2003b).

030945 Final EATS 5-Yr Rvw Rpt-doc 3-4

Additional descriptions of the contaminants are provided in Section 3.5 of this report and inprevious annual reports (FWENC, 2002 and 2003b).

An analysis of risks to human health and the environment posed by contamination in the OU 5area was performed. Occupational exposure is the most likely exposure scenario at OU 5. Therisk assessment found that occupational exposure to groundwater did not present significant risksto site workers (DoN, 1996). This risk assessment used conservative assumptions, includingworkers onsite for 8 hours a day for 25 years and the inhalation of VOCs pathway (PRC, 1995).Human health risks in the OU 5 human health risk assessment are based on domestic use ofupper aquifer groundwater, even through OU 5 groundwater is not used as a drinking watersource (DoN, 1996). Residential exposure pathways included groundwater ingestion, inhalationof volatilized chemicals, and ingestion of irrigated produce (DoN, 1996).

An ecological risk assessment was also conducted. Current ecological receptors in surface waterwere determined not to be at risk from any contaminated groundwater exfiltrating from OU 5groundwater. As a conservative measure, the maximum concentrations for the COCs detected ingroundwater since 1989 were compared to ecological benchmarks. Results of the risk assessmentdemonstrated that even if the highest levels of COCs detected in the groundwater were todirectly exfiltrate into the ditches, there would be no adverse ecological effects (DoN, 1996).

030945 Final EATS 5-Yr Rvw Rpl.doc 3-5



4.0 REMEDIAL ACTIONS

This section describes the remedial actions conducted at the site, including remedy selection,remedy implementation, EATS treatment performance, and operation and maintenance.

4.1 REMEDY SELECTION

OU 5 was originally identified in the early 1990s to facilitate the Remedial Investigation (RI)/FSprocess (DoN, 1996). The ROD (DoN, 1996) was signed by DoN, EPA Region 9, CaliforniaDepartment of Toxic Substances Control (DTSC), and the San Francisco Bay RWQCB in June1996. There is no Explanation of Significant Differences (ESDs) for OU 5.

The major components of the remedy selected for the southern OU 5 plume are extraction andtreatment of groundwater using an air stripping system followed by discharge, institutionalcontrols, and groundwater monitoring (DoN, 1996). The ROD (DoN, 1996) estimates that theselected remedy will take at least 50 years to reach the cleanup standards. The ROD specifiesthat no action is required, except for groundwater monitoring, for the OU 5 northern plume.

The groundwater cleanup standards for the OU 5 southern plume, as specified in the ROD, arethe MCLs for each COC:

• l,2-DCA-0.5(ig/L

• l,2-DCE-6ug/L

PCE-S^ig/L

• VC - 0.5 [ig/L.

The ROD specifies that, due to the lithology, achieving the groundwater cleanup standards maynot be technically feasible. The DoN will monitor the performance of the system to assesssystem effectiveness, and the selected remedy may be reevaluated, as appropriate (DoN, 1996).

4.2 REMEDY IMPLEMENTATION

Design of EATS began in 1996. The preliminary design was submitted to EPA, RWQCB, andNASA in February 1997. Comments on the preliminary design were addressed in the finaldesign in May 1997. Construction began in July 1997. Construction was completed, and thesystem began operating in January 1999. The construction cost of EATS was $2,331,929(TtEMI, 2001 a).

030945 Final EATS S-Yr RvwRptdoc 4-1

4.2.1 EATS Extraction

EATS began operating in January 1999. The EATS extraction system consists of five extractionwells piped to ia treatment system. All of the extraction wells (EXW-1 through EXW-5) arecompleted in the Al aquifer zone. EATS treatment consists of two major unit operations: an airstripper and liquid phase granular activated carbon (GAC) vessels in series. The GAC units wereadded during the design phase as a safety factor for uncertainties and to polish treatedgroundwater from the air stripper. Based on operational data, the GAC units are redundant andhave not been required to meet discharge requirements. The system components are shown onthe process flow diagram (Figure 4-1).

The EATS extraction system is operated to maintain capture zones within limits imposed byaquifer and extraction well conditions. The EATS treats about 30 gpm of groundwater. This isconsistent with the design specifications (TtEMI, 200la). Contaminated water is pumped fromthe extraction wells and treated to remove the contaminants to levels specified in the NationalPollutant Discharge Elimination System (NPDES) permit before being discharged. Since watercannot be reused and in accordance with the ROD, the treated water is discharged to the stormwater system in accordance with the NPDES general permit CAG912003, Order No. 99-051.

4.2.2 Institutional and Engineering Controls

Engineering and institutional controls specified in the ROD include fencing of the treatmentsystem area, operation and maintenance of Building 191 and the storm water drainage system,and domestic use restrictions on the groundwater at OU 5,(DoN, 1996).

Engineering controls related to active extraction and treatment of the groundwater plume wereimplemented as part of the EATS remedial construction in 1997 and 1998. Groundwatermonitoring began in March 1999 and continues.

Fencing of the treatment system area was specified in the ROD. The treatment system wasfenced as part of the remedial construction of EATS. The fence is kept locked to maintain sitesecurity.

Operation and maintenance of Building 191 and the storm drainage system were specified asinstitutional controls in the ROD. The OU 5 ROD states that without continued operation ofBuilding 191 (the pump station), flooding of the northern end of the runways and surroundingareas, including the area overlying OU 5, would occur during the rainy season. Implementationof engineering and institutional controls is discussed in the memorandum of agreement (MOA)for institutional controls between the DoN and NASA, signed in November 1999. This MOAaddresses controls for OUs 1 and 5, and it is included in the Draft Final Interim Remedial ActionReport for Site 1 and Site 2 Landfill Closure, dated September 25, 2001 (TtEMI, 2001b). This

030945 Final EATS S-Yr [h™ Rpi.doc 4-2

MOA states that NASA agrees to maintain the Building 191 pump station and drain and subdrainsystem as long as it either owns the property or maintains operational control over the site.

This MOA also states: "Furthermore, in the event of a future conveyance of the property, NASAwill notify subsequent owners of this restriction by appropriate notices and land use restrictions."The Navy has requested that NASA incorporate land use controls language in the appropriateland use planning document(s), to include access restrictions on the domestic use of the OU 5groundwater and notification to subsequent landowners of these restrictions by appropriatenotices and implementation of appropriate land use restrictions. NASA's Comprehensive UsePlan (NASA, 1994) currently contains language restricting access and development in the OU 5area because of safety considerations related to munitions storage and runway/air operations.There are no drinking water wells in the OU 5 area, and NASA's Comprehensive Use Planindicates no land use change is planned. During the implementation of the remedy, exposurepathways that could result in unacceptable risk are being controlled. Institutional controlrestrictions prevent exposure to, or ingestion of, contaminated groundwater.

4.2.3 Groundwater Monitoring

The ROD specifies groundwater monitoring as part of the selected remedy (DoN, 1996).Groundwater monitoring has been instituted and is being conducted as required by the ROD.

A long-term groundwater monitoring plan was developed and issued in 1997 (PRC, 1997).EATS startup began on January 26, 1999 (TtEMI, 200la). Long-term groundwater monitoringbegan in March 1999.

Groundwater monitoring, including water level measurements, wells to be sampled, analyses,and sampling frequency for the OU 5 southern and northern plumes, is addressed in the EATSFinal Long-Term Groundwater Monitoring Plan (PRC, 1997). Groundwater monitoringcontinues to be conducted as part of the operation and maintenance (O&M) activities. Recentgroundwater sampling events have deviated from the EATS Final Long-Term GroundwaterMonitoring Plan (PRC, 1997) as agreed upon or requested by EPA, with concurrence fromRWQCB. Deviations have primarily been related to sampling of additional wells and additionalanalyses to enable more complete evaluation of the OU 5 southern plume. Section 4.4 describeskey O&M activities for EATS, including current groundwater monitoring.

4.3 EATS TREATMENT PERFORMANCE

EATS began operating on January 26, 1999. Functional testing was completed in April 1999.The system was considered to be operating properly and successfully in May 1999 (TtEMI,200la). EATS maintains groundwater capture within the limits imposed by aquifer andextraction well conditions. Capture zone maps can be found in the Final First AnnualGroundwater Report for WATS and EATS (Figures 5-2 and 5-3) (FWENC, 2002), Final 2001

030945 Final EATS 5-Yr R™ Rpl.doc 4-3

Annual Groundwater Report for WATS and EATS (Figures 5-16 through 5-19) (FWENC,2003b), and 2002 Annual Groundwater Report for WATS and EATS (Figures 3-1 through 3-4)(TtFW, 2004). i

From startup through December 2002, EATS operated 94 percent of the time (Table 4-1). Morethan 59 million gallons of ground-water were processed through EATS during the first 4 years ofoperation. The calculated mass of VOCs removed during this time is approximately 21 pounds(Ibs) (Table 4-1;-Figure 4-2). EATS operational data are provided in the Final First AnnualGroundwater Report for WATS and EATS (Tables 5-1, O-2, and O-4) (FWENC, 2002), Final2001 Annual Groundwater Report for WATS and EATS (Table 5-1) (FWENC, 2003b), and 2002Annual Groundwater Report for WA TS an dEATS (Table 3-5) (TtFW, 2004).

The mass removal at EATS declined from 1999 through 2002 (Table 4-1). When contaminantconcentrations are low, such as at EATS (maximum COC concentration of 51 [J-g/L of TCE in2002), contaminant removal from an aquifer at a decreasing or even constant-rate is typical ofchemical tailing or rebound effect. If there is chemical tailing or rebound, then pump-and-treatsystems, as documented in EPA literature, may not be effective or efficient in cleaning up thelow concentrations of VOCs. Implementation of the EATS Evaluation Work Plan, asrecommended in this five-year review, will provide further data.

Other lines of evidence also indicate that EATS may not be effective or efficient in cleaning upthe low concentrations of VOCs in the groundwater. As shown in Table 4-1, EATS only removesapproximately 5 pounds of contaminants per year (TCE, PCE, cis-l,2-DCE, and VC), whichaverages less than 0.5 pounds of contaminants removed each month. This is not consideredefficient contaminant removal. Both typical pump and treat contaminant removal rates andremoval rates of other Moffett systems are significantly higher. A comparison to contaminantremoval rates at'. WATS shows a dramatic difference. In 2002, the total flow at WATS wasapproximately 36.3 million gallons, with 539 pounds of contaminant removed. In 2002, the totalflow at EATS was approximately 15.8 million gallons, with approximately 5.4 pounds ofcontaminant removed (TtFW, 2004).

The EATS ROD specifies that EATS would need to run for at least 50 years to clean up thegroundwater to the clean-up standards presented in the ROD, if practicable. Mass removal isexpected to decrease in the future, as is typical for life-cycle curves for pump and treat systemswith low contaminant concentrations (EPA, 1996). Therefore, it is not considered efficient tocontinue to operate EATS (per the ROD, for an estimated minimum of 50 years) whencontaminant removal rates are currently so low and expected to decrease.

The fact that the mass removed decreased, while system costs generally increased(Section 4.4.2), also indicates that EATS efficiency has decreased (FWENC, 2003b). Therecommendation of this five-year review report is to complete the implementation of the Final


EATS Evaluation Work Plan (FWENC, 2003a) in order to collect field data for the evaluation ofthe effectiveness of EATS and applicability of other potential remedial options in achieving thegroundwater cleanup standards specified in the ROD.

4.4 OPERATION AND MAINTENANCE

O&M activities began upon system startup and are ongoing. O&M activities include security ofthe treatment system, activities required to operate and maintain the system and extraction wells,groundwater monitoring, and NPDES compliance monitoring. The EATS Final O&M Manual(TtEMI, 2000) and the Final Site-Specific Contractor Quality Control Plan (FWENC, 2001)address security and activities required to operate and maintain the system and the extractionwells. Groundwater monitoring is addressed in the EATS Final Long-Term GroundwaterMonitoring Plan (PRC, 1997). System and effluent monitoring is conducted in accordance withNPDES general permit CAG912003, Order No. 99-051.

The fence is kept locked to maintain site security. Maintenance and repairs are conducted asrequired to keep the system running. There have been no problems in the implementation ofsystem O&M. O&M activities, NPDES sampling results, and operational data are presented inthe quarterly NPDES reports and the annual groundwater reports. In addition, operational dataare reported to the RWQCB and EPA on a monthly basis through Base Realignment and Closure(BRAC) Cleanup Team (BCT) meeting handouts.

Groundwater monitoring began in March 1999 and is ongoing. It includes groundwater samplingand quarterly measurement of water levels in EATS groundwater monitoring wells. Groundwatersampling began on a quarterly basis and is currently conducted on an annual basis, in accordancewith the EATS Final Long-Term Groundwater Monitoring Plan (PRC, 1997). Groundwatermonitoring has been conducted as specified in this plan or in accordance with deviationsapproved by EPA and RWQCB.

4.4.1 VOC Emission Monitoring—Air Stripper

System inspections for the EATS air stripper are conducted as specified in the EATS Final O&MManual (TtEMI, 2000). Maintenance activities are performed regularly and may also be basedon the findings of the inspections. The minimum inspection frequency has been followed sinceEATS startup.

Results of VOC emission monitoring show that emissions are well below the regulatory gasdischarge limit. Due to the extremely low levels of individual VOCs in the exit gas stack, totalVOC emission rates from the EATS air stripper are determined by differences in VOCconcentrations in the influent and effluent water from the air stripper. Historically, total VOCemissions from the air stripper have been an order of magnitude below the maximum regulatorygas discharge limit (TtEMI, 2001 a). Based, on monthly samples collected from EATS during

030945 Final EATS 5-Yr Rvw Rpt.doc 4-5

2001, the average discharge of the air stripper gas was less than 0.017 pound total VOCs/day.This is well bejow the maximum Bay Area Air Quality Management District (BAAQMD) gasdischarge limit of 1 pound per day. Because the EATS extraction rate and influent contaminantconcentrations are unlikely to increase significantly, it is improbable that VOC emissions fromthe EATS air stripper will ever exceed the 1.0 pound of VOC per day emission threshold(TtEMI,2001a).

4.4.2 Operation and Maintenance Costs

System O&M costs before October 1999 are considered startup costs and are included in thesystem construction costs. Construction costs for EATS were not used in this analysis. AnnualO&M costs arei presented in Table 4-2. Apparent O&M cost discrepancies occur because thedifferent contractors operating EATS used various accounting methods for O&M costs asdetailed below:

• From startup to October 1999, O&M costs were included in the construction cost.

• From October 1999 through January 2001, O&M costs included half of themisqellaneous costs, including reporting.

• After January 2001, all miscellaneous costs are included in the reported O&M cost.

The original annual O&M cost estimated in the Final Operable Unit 5 Feasibility Study Report(PRC, 1995) was $263,300. This is similar to the $260,455 spent in 2001.

Figure 4-3 shows the variability of the average monthly treatment system flow and its relation tothe contaminant removal cost rate (dollars per pound). A linear regression of the averagemonthly flow <Jata shows that there is no increase or decrease in the trend over the EATSoperating period. A linear regression of the contaminant removal cost rate displays an increasingtrend.

4.5 ENFORCEMENT ACTIONS

No enforcement actions have been taken at EATS.

030945 Final EATS S-Yr Rvw Rpl.doc 4-6

5.0 FIVE-YEAR REVIEW PROCESS

The EPA's Comprehensive Five-Year Review Guidance (EPA, 2001) and DoN Policy forConducting CERCLA Statutory Five-Year Reviews (DoN, 2001b) outline the five-year reviewprocess and the elements required. This section of the document describes the process andpresents the data reviewed.

5.1 ADMINISTRATIVE COMPONENTS

The required administrative components include the notification of potential interested parties,identification of the five-year review team, and the schedule for the five-year review.

5.1.1 Notification of Potentially Interested Parties of Initiation of Review Process

Potentially interested parties were notified of the initiation of the five-year review via thequarterly Restoration Advisory Board (RAB) meeting. The EATS Five-Year Review Report wason the agenda, a presentation was provided, and questions were addressed during the thirdquarter 2002 RAB meeting held on October 10, 2002. Review sign-up sheets for the Draft andFinal OU 5 2002 Five-Year Review Reports were circulated during the October 10, 2002 RABmeeting. Potentially interested parties participating in RAB meetings include communityrepresentatives; federal, state, and local government agency representatives; DoNrepresentatives; and contractors providing support to DoN at Moffett.

5.1.2 Identification of Five-Year Review Team

The five-year review team consists of the DoN BRAC Environmental Coordinator, Ms. AndreaEspinoza, and Remedial Project Manager, Ms. Mary Parker, with technical support fromFWENC.

5.1.3 Outline of Components and Five-Year Review Schedule

When the five-year review began in May 2002, the review team established the review schedule.Its components consist of the following:

• Community Involvement

• Document Review

• Data Review

• Site Inspection

• OU 5 Five-Year Review Report Development and Review

030945 Final EATS 5-Yr R™ Rptdoc 5-1

5.2 COMMUNITY INVOLVEMENT

Community notification of the five-year review initially occurred during the October 10, 2002,RAB meeting. RAB meeting participants included community representatives, as well as federal,state, and local government agency representatives. The five-year review also was discussed atsubsequent RA$ meetings. The five-year review report also has been discussed at monthly BCTmeetings.

The community will be notified when the final five-year review has been issued. Placement of apublic notice in local newspapers is planned. Results of the five-year review will be provided tothe public via the RAB document sign-up process and placement of a copy of the final report inthe local information repository at the Mountain View Library.

5.3 DOCUMENT REVIEW

This five-year review consisted of examining relevant documents, including the RI report, FSreport, ROD, design and construction reports/records, O&M manuals and records, long-termgroundwater monitoring plan, annual reports, and monitoring data. Applicable or relevant andappropriate requirements (ARARs) and cleanup standards, as listed in the June 28, 1996, ROD(DoN, 1996), were reviewed. A list of these documents is included in Appendix A.

5.4 DATA REVIEW

System and groundwater data collected since January 1999 were reviewed. Detailed data andtechnical evaluations are presented in the annual reports: the Final First Annual GroundwaterReport for WATS and EATS (FWENC, 2002), which includes 1999 and 2000 data, the Final2001 Annual Groundwater Report for WATS and EATS (FWENC, 2003b), and the 2002 AnnualGroundwater Report for WATS and EATS (TtFW, 2004).

Performance is summarized as follows:

• A VOC mass of approximately 21 pounds was removed by EATS extraction wellsfrom startup through December 2002.

• From the startup of EATS through the 2001 reporting period, 28 percent of the massremoved was TCE, 38 percent was cis-l,2-DCE, 31 percent was PCE, and 3 percentwas VC (FWENC 2003b).

• The mass removal at EATS for the 2002 reporting period was as follows: 32.0percent TCE, 29.2 percent cis-l,2-DCE, 35.2 percent PCE, and 3.6 percent VC.

• The mass removal per million gallons treated at EATS declined from 1999 to 2002.The fact that the cumulative mass removed during 2001 decreased compared to thatof 2000 while system costs increased (Section 4.4.2) indicates that EATS efficiencyhas decreased (FWENC, 2003b).

030945 Final EATS S-Yr Rvw Rpt.doc 5-2

• The COC concentrations have decreased or remained stable, and are low. Themaximum COC concentration detected during November 2002 groundwatermonitoring well sampling was 51 ug/L of TCE.

• Since COC concentrations are so low, the removal rates in the extraction wells mayhave reached the asymptotic portion of the removal rate curves.

When contaminant concentrations are low, such as at EATS (maximum COC concentration of51 jag/L of TCE in 2002), contaminant removal from an aquifer at a decreasing or even constant-rate is typical of chemical tailing or rebound effect. If there is chemical tailing or rebound, thenpump-and-treat systems, as documented in EPA literature, may not be effective or efficient incleaning up the low concentrations of VOCs. The recommendation of this five-year reviewreport is to complete the implementation of the EATS Evaluation Work Plan in order to providefurther data. The EATS cumulative contarninant mass removal and cumulative volume of watertreated are presented graphically on Figure 4-2. EATS operational data are summarized on Table4-1. Table 4-1 shows the decreasing mass removal since EATS began operating in January 1999.In 1999, a total of 0.39 pounds of contaminant mass were removed per million gallons ofgroundwater treated by EATS. In 2002, a total of 0.34 pounds of contaminant mass wereremoved per million gallons treated. _ L_

Other lines of evidence also indicate thatJEATS may not be effective or efficient in cleaning upthe low concentrations of VOCs in the groundwater. As shown in Table 4-1, EATS only removesapproximately 5 pounds of contaminants per year (TCE, PCE, cis-1, 2-DCE, and VC), whichaverages less than 0.5 pounds of contaminants removed each month. This is not consideredefficient contaminant removal. Both typical pump and treat contaminant removal rates andremoval rates of other systems at Moffett are significantly higher. A comparison to contaminantremoval rates at WATS shows a dramatic difference. In 2002, the total flow at WATS wasapproximately 36.3 million gallons, with 539 pounds of contaminant removed. In 2002, the totalflow at EATS was approximately 15.8 million gallons, with approximately 5.4 pounds ofcontaminant removed (TtFW, 2004).

The EATS ROD specifies that EATS would need to run for at least 50 years to clean up thegroundwater to the clean-up standards presented in the ROD, if practicable. Mass removal isexpected to decrease in the future, as is typical for life-cycle curves for pump and treat systemswith low contaminant concentrations (EPA, 1996). Therefore, it is not considered efficient tocontinue to operate EATS (per the ROD, for an estimated minimum of 50 years) whencontaminant removal rates are currently so low and expected to decrease. Data collected duringimplementation of the EATS Evaluation Work Plan will allow evaluation of effectiveness andefficiency and applicability of other potential remedial options in achieving the groundwatercleanup standards specified in the ROD, potentially in a much shorter timeframe. Other remedialalternatives such as in-situ treatment may be more efficient and, in addition to decreasing thetimeframe for cleanup (short-term protectiveness), could increase overall protectiveness of

030945 Final EATS 5-YrRvwRpl.doc 5-3

human health and the environment because contaminated groundwater would not need to beextracted for treatment.

Figure 4-3 show;s the variability of the average monthly treatment system flow and its relation tothe contaminant removal cost rate (dollars per pound). A linear regression of the averagemonthly flow data shows that there is no increase or decrease in the trend over the EATSoperating period- A linear regression of the contaminant removal cost rate displays an increasingtrend.

Table 3-2 cornpares 1998 (pre-EATS operation) and 2002 groundwater monitoring andextraction well;concentrations for 1,1-DCE, 1,2-DCA, cis-l,l-DCE, PCE, TCE, and VC. Ingeneral, concentrations have decreased slightly or remained approximately the same.

Figures 3-4 through 3-9 provided concentration trend graphs vs. time for the COCs specified inthe ROD (TCE, cis-l,2-DCE, PCE, VC, 1,2-DCA, and 1,1-DCE) for the groundwater monitoringand extraction wells listed on Table 3-2 and wells W3-1, WU5-1, W7-10, and WSW-5. Theseare the wells that were sampled both in 1998 and 2002 as well as the wells containing themaximum concentration of one of the COCs in 2002. On each of these graphs, a line is plottedshowing the ROD cleanup standard (the MCL) for each COC.

Review of Table 3-2 and Figures 3-4 through 3-9 shows that COCs in many wells are currentlynot detected or detected at concentrations below the cleanup goal specified in the ROD (theMCL). Since 1998, 1,1-DCE was seldom detected and concentrations in all wells were below thecleanup goal specified in the ROD (the MCL). In 2002, 1,2-DCA was seldom detected, with amaximum concentration of 0.6 j-ig/L. VC was nondetect in many wells in 2002, with a maximumconcentration of 4 jJ-g/L. In 2002, PCE was detected at a concentration above the cleanup goalspecified in the ROD (the MCL) in only two groundwater monitoring wells, wells WU5-24 andW7-10.

Figures 3-1 and 3-2 showed the approximate extent of the VOC plumes in 1996 and 2002,respectively. Although there are differences in the boundaries of these plumes, the overall plumelocation and average concentrations are generally stable. Additional evaluation, including on acompound-specific basis, is provided in the 2002 Annual Groundwater Report for WATS andEATS (TtFW, 2004).

Both chemical and operational data indicate that the Final EATS Evaluation Work Plan(FWENC, 2003a) should be implemented to collect field data for the evaluation of theeffectiveness of EATS and applicability of other potential remedial options in achieving thegroundwater cleanup standards specified in the ROD. Prior to issuance of this five-year reviewreport, the EATS Evaluation Work Plan was issued and implementation of activities describedtherein began.


5.5 SITE INSPECTION

Regularly scheduled system performance inspections of EATS occur and are documented inaccordance with the East-Side Aquifer treatment System Final Operation and MaintenanceManual (TtEMI, 2000).

The five-year review inspection for EATS was conducted on August 6, 2002, by Mr. MikeKlosky, FWENC Project Engineer, Mr. Bill Ogle, the FWENC Site Superintendent, andMr. Duane Harrison, the FWENC Site Technician. The inspection checklist utilized for the five-year review of EATS is presented in Appendix B. Photographs taken of the sites are presented inAppendix C. The scope of the inspections was to address the issues identified in the guidancedocuments for conducting five-year reviews (EPA, 2001) and (DoN, 2001b). The purpose of theinspections was to assess the protectiveness of the remedy, including conditions of thegroundwater extraction wells, the piping system, the treatment system, and institutional controls.

No significant issues have been identified at any time regarding the integrity of the remedialactions implemented at EATS. The remedy is functioning as designed.

5.6 INTERVIEWS

Formal interviews were not conducted as part of the five-year review. Sufficient information wasavailable from existing documents, discussions with DoN personnel familiar with the sites, andthe Site Superintendent responsible for overseeing field activities. The public was informed ofthe five-year review through the RAB, and input from the public was obtained during RABquestion-and-answer sessions.

5.7 SUMMARY OF EATS EVALUATION WORK PLAN

The objective of the EATS Evaluation Work Plan is to collect field data for the evaluation of theeffectiveness of EATS and applicability of other potential remedial options in achieving thegroundwater cleanup standards specified in the ROD (DoN, 1996). Elements of this Work Planinclude the following:

• Perform aquifer testing to evaluate well and aquifer hydraulic parameters for theEATS extraction wells.

• Collect and analyze groundwater samples to assess potential COC rebound.

• Collect and analyze groundwater samples to evaluate the stability of the EATSplume, including analysis of monitored natural attenuation (MNA) parameters, andcollect soil samples to provide site-specific organic carbon content.

• Conduct a nutrient enhancement (NE) pilot test at two groundwater "hot spots" todecrease groundwater contaminant concentrations and collect data to enableevaluation of NE as a potential additional or alternate remediation technology.

030MS Final EATS S-Yi Rv» Rpuioc 5-5

Two phases of field activities are planned. Phase I field activities began in 2003 and includeaquifer testing, soil sampling to provide site-specific organic carbon content, and groundwatersampling to assess potential COC rebound, plume stability, and MNA parameters. Phase I workwill provide site-specific hydrologic and chemical data to enable evaluation of EATSeffectiveness and applicability of other potential remedial options in achieving the RODgroundwater cleanup standards. An NE pilot test will be conducted at two groundwater "hotspots" within the EATS plume during Phase II to decrease groundwater contaminantconcentrations and collect data to enable evaluation of NE as a potential additional or alternateremediation technology.

030945 Final EATS 5-Yr Rvw RpLdoc 5-6

6.0 TECHNICALASSESSMENT

This technical assessment section of the QU 5 Five-Year Review Report asks three questions:

Question A: Is the remedy functioning as intended by the decision documents?

Question B: Are the exposure assumptions, toxicity data, cleanup levels, and remedialaction obj ectives used at the time of the remedy still valid?

Question C: Has any other information come to light that could call into question theprotectiveness of the remedy?

Each of these questions is addressed in the. following subsections, building upon the informationand data summaries already presented.

6.1 QUESTION A: IS THE REMEDY FUNCTIONING AS INTENDED BY THEDECISION DOCUMENTS?

The three major components of the OILS JR.OD, construction and operation of the groundwatertreatment system, institutional controls, and groundwater monitoring, are in place andfunctioning as intended in the ROD. .The current suite of monitoring parameters and thegroundwater sampling frequency are adequate to evaluate the performance of EATS. ?

The review of documents, ARARs, risk assumptions, and results of the site inspection indicatethat the remedy is functioning as designed. The system was designed to maintain drawdown inthe extraction wells at a cumulative rate,of.30 gpm (TtEMI, 2001a). The extraction system hasaveraged 28 gpm, when calculated based Qjithe cumulative amount of groundwater treated fromstartup in January 1999 through December 2002. The startup period and downtimes have beenfactored into this average flow rate calculation. EATS maintains groundwater capture within thelimits imposed by aquifer and extraction well conditions (FWENC, 2003b). From startup throughDecember 2002, EATS operated 94 percent of the time, and O&M procedures are appropriate.

The treatment system is well designed and constructed with proper instrumentation, and isappropriate for the groundwater contaminants. Current maintenance activities do not suggest anytrend in deterioration of the treatment system. The implementation and scope of O&Mprocedures are more than adequate to ensure current and long-term protectiveness of the remedy.The O&M procedures include ample monitoring procedures (i.e. monthly treatment systeminfluent/effluent samples, annual groundwater samples and plume delineation, and preventativemaintenance programs) to ensure proper operation of the treatment system. The treatment systemcontains electronic instrumentation with computer control that provides automatic shutdown andalarming off site, as necessary, to ensure proper operation and rapid response to any difficultiesthat might arise. The air stripper and GAC effectively remove contaminants from extractedgroundwater prior to discharge so that NPDES requirements are met. There are no early

03094S Final EATS 5-Yr Rvw RpLdoc 6-1

indicators of potential problems with the treatment system itself. However, due to the lowconcentration of extracted contaminants and low mass removal rates, opportunity exists tooptimize and/or select more effective and economical remedies through implementation of therecommended EATS Evaluation Work Plan.

Exposure pathways that could result in unacceptable risk are being controlled. Access controlsare in place (fenced with locked gate). Institutional controls are in place and prevent exposure to,or ingestion of, contaminated groundwater.

During November 2002 groundwater sampling, TCE was detected in the southern plume at amaximum concentration of 51 |4.g/L. The highest concentration of PCE detected in samples fromEATS groundwater monitoring wells during November 2002 sampling was 44 u.g/L. hi 2002,PCE was detected at a concentration above the cleanup goal specified in the ROD (the MCL) insamples from only two groundwater monitoring wells, wells WU5-24 and W7-10. The maximumconcentration of cis-l,2-DCE detected in the November 2002 sampling event was 19 p.g/L. OtherCOCs in samples from many wells are currently not detected or detected at concentrations belowthe cleanup goal specified in the ROD (the MCL). Since 1998, 1,1-DCE was seldom detectedand concentrations in samples from all wells were below the cleanup goal specified in the ROD(the MCL). In 2002, 1,2-DCA was seldom detected, with a maximum concentration of 0.6 |-ig/L.VC was nondetect in samples from many wells in 2002, with a maximum concentration of 4jj.g/L. Since the VOC concentrations are so low, the removal rates in the extraction wells mayhave reached the asymptotic portion of the removal rate curves (EPA, 1996). When contaminantconcentrations are low, such as at EATS (maximum COC concentration of 51 |J.g/L of TCE in2002), contaminant removal from an aquifer at a decreasing or even constant-rate is typical ofchemical tailing or rebound effect. If there is chemical tailing or rebound, then pump-and-treatsystems, as documented in EPA literature, may not be effective or efficient in cleaning up thelow concentrations of VOCs.

6.2 QUESTIONS: ARE THE EXPOSURE ASSUMPTIONS, TOXICITY DATA,CLEANUP LEVELS, AND REMEDIAL ACTION OBJECTIVES USED AT THETIME OF THE REMEDY SELECTION STILL VALID?

ARARs provided in the June 28, 1996, OU 5 ROD, were reviewed and evaluated to determine ifany modifications had occurred that might affect the ROD's remedial action objectives oroperation of EATS since the ROD was finalized. Based on the evaluation, none of the chemical-specific ARARs (for example, federal or state drinking water MCLs, San Francisco BayRWQCB Basin Plan) originally cited in the ROD has changed. Likewise, the location-specificARARs, including wetland disturbance regulations, coastal zone activities, and archaeologicaland historical preservation act provisions of the ROD, have not changed since it was finalized. Inaddition, the action-specific ARARs cited in the ROD (which relate to surface water discharges,discharges to groundwater, air emissions, and tank storage requirements), have not changed in amanner that affects the operation of EATS or effluent discharge limits to the Northern channel.


One of the action-specific ARARs from the ROD cites point-source control provisions(discharge standards) in accordance with the RWQCB Basin Plan. The standards actuallyreferenced within the Basin Plan have, however, changed. Specifically, the Basin Plan referencesstandards that were adopted from EPA's Ambient Water Quality Criteria, as adopted by theRWQCB in 1986. In 2000, the California Toxics Rule (CTR), which provides updated andadditional standards for discharges to surface waters, was promulgated. The CTR standards forVOCs are not lower than the preestablished discharge limits within the NPDES permit forEATS. The new CTR standards do not, therefore, affect the existing NPDES discharge standardsfor the treated effluent from EATS and do not affect the protectiveness of the remedy.

Land use has not changed, nor is it expected to change in the future. There are no buildings overthe EATS plume. Since no buildings overlie the plume, indoor air is not a concern. Air stripperVOC emissions are approximately an order of magnitude below the B AAQMD threshold. Thereare no changes in the physical conditions that would affect the protectiveness of the remedy.There are no new contaminants identified, no unanticipated toxic byproducts, and no changes inthe exposure pathways. Cleanup standards identified in the ROD, which are the MCLs, are stillvalid.

6.3 QUESTION C: HAS ANY QTHEB INFORMATION COME TO LIGHT THATCOULD CALL INTO QUESTION THE PROTECTIVENESS OF THE REMEDY?

There is no new information that calls into question the protectiveness of the remedy. There havebeen no natural disasters that have adversely impacted the effectiveness of the selected remedy.There have been no land use changes. Results of the risk assessment demonstrated that even ifthe highest levels of COCs detected in the groundwater since 1989 were to directly exfiltrate intothe ditches, there would be no adverse ecological effects (DoN, 1996).

6.4 TECHNICAL ASSESSMENT SUMMARY

According to the data reviewed and the site inspections, the EATS is functioning as intended bythe ROD (DoN, 1996). There have been no changes in the physical conditions of the sites thatwould affect the protectiveness of the remedy. The remedy is in accordance with ARARs cited inthe ROD (DoN, 1996). There is no otheOnformation that calls into question the protectivenessof the remedy.

030945 Final EATS 5-Y: Rvw Rptdoc 6-3


030945 Final EATS 5-Yi Rv» Rpldoc 6-4

7.0 ISSUES

Issues identified during this first five-year review are identified below.

Issue

EATS may not be efficient in cleaning up thelow concentrations of VOCs in the groundwater.

Currently AffectsProtectiveness

(Y/N)

N

Affects FutureProtectiveness

(Y/N)

N

Abbreviations and Acronyms:

EATS - East-Side Aquifer Treatment SystemN No ,: ::;VOCs - volatile organic compoundsY Yes



030945 Final EATS 5-Yr Rvw Rjx.doc 7-2

8.0 RECOMMENDATIONS AND FOLLOW-UP ACTIONS

Recommendations and follow-up actions are identified below.

Issue

EATS may not beefficient incleaning up thelow concentrationsofVOCsinthegroundwater.

Recommendations/Follow-Up Actions

Completeimplementation of theEATS Evaluation WorkPlan to collect fielddata for evaluation ofthe effectiveness andefficiency of EATS andapplicability of otherpotential remedialoptions in achieving thegroundwater cleanupstandards specified inthe ROD. Due to thelow concentrations ofextracted contaminantsand low mass removalrates, opportunity existsto optimize and/orselect more effectiveand economicalremedies throughimplementation of theEATS Evaluation WorkPlan.

PartyResponsible

DoN

OversightAgency

DoN,RWQCB,

EPA

MilestoneDate

May 2003

AffectsProtectiveness?

(Y/N)

Current

N

Future

N


DoN — Department of the NavyEATS — East-Side Aquifer Treatment SystemEPA - U.S. Environmental Protection AgencyN NoRWQCB - Regional Water Quality Control BoardVOCs — volatile organic compoundsY Yes




9.0 PROTECTIVENESS STATEMENT

The remedy at Operable Unit 5 includes extraction and treatment of the southern plumegroundwater by the East-Side Aquifer Treatment System, groundwater monitoring, andinstitutional controls. The remedy at Operable Unit 5 is currently protective of human health andthe environment because there is no evidence of current or potential exposure. During theimplementation of the remedy, exposure pathways that could result in unacceptable risk arebeing controlled. In order for the remedy to remain protective until cleanup levels are met,institutional control restrictions preventing exposure to, or ingestion of, contaminatedgroundwater must remain in place. Long-term protectiveness of human health and theenvironment is expected to be achieved upon attainment of groundwater cleanup goals specifiedin the Record of Decision.




10.0 NEXT REVIEW

The next five-year review for EATS (OU 5) is required by 2010, which is five years from thesignature date of this review.



030945 Final EATS 5-Y[ Rvw Rpl.doc 10-2

11.0 REFERENCES

Department of the Navy (DoN). 1996. Moffett Federal Airfield Final Operable Unit 5 Record ofDecision, Mqffett Federal Airfield, California. June 28.

. 2001 a. Guidance for Optimizing Remedial Action Operation.November 29.

. 2001b. Policy for Conducting Comprehensive Environmental Response,Compensation, and Liability Act (CERCLA) Statutory Five-Year Reviews. November.

Foster Wheeler Environmental Corporation (FWENC). 2001. Final Site-Specific ContractorQuality Control Plan, Moffett Federal Airfield, Moffett Field, California.

. 2002. Final First Annual Ground-water Report for WATS and EATS,Moffett Federal Airfield, Moffett Field, California.

. 2003a. Final EATS Evaluation Work Plan. Moffett Federal Airfield,Moffett Field, California. January 14.

. 2003b. Final 2001 Annual Ground-water Report for WATS and EATS,Moffett Federal Airfield, Moffett Field, California. January 31.

Iwamura, T.I. 1980. Saltwater Intrusion Investigation in the Santa Clara County Baylands Area,^— California. Unpublished Report of Santa Clara Valley Water District.

National Aeronautics and Space Administration (NASA). 1994. Moffett Field ComprehensiveUse Plan. Moffett Field, California. September.

PRC Environmental Management, Inc. (PRC). 1995. Final Operable Unit 5 Feasibility StudyReport, Volume 1; Moffett Federal Airfield, California. August 31.

. 1997. East-Side Aquifer Treatment System Final Long-TermGroundwaterMonitoring Plan. Moffett Federal Airfield, California. July 3.

State Water Resources Control Board (SWRCB). 1998. Resolution No. 88-63, Adoption ofPolicy entitled "Sources of Drinking Water." May.

Tetra Tech EM, Inc. (TtEMI). 2000. East-Side Aquifer Treatment System Final Operation andMaintenance Manual. September 29.

. 200la. Draft Final Interim Remedial Action Report, East-Side AquiferTreatment System (EATS). May 18.

_. 2001b. Draft Final Interim Remedial Action Report for Site I and Site 2Landfill Closure. Moffett Federal Airfield, Moffett Field, California. September 25.


Tetra Tech FW, Inc. (TtFW). 2004. 2002 Annual Groundwater Report for WATS and EATS,former NAS Moffett Field, Moffett Field, California. June 18.

U.S. Environmental Protection Agency (EPA). 1996. Pump-and-Treat Ground-WaterRemediation, A Guide for Decision Makers and Practitioners. EPA 625-R-95-005. July.

. 2001. Comprehensive Five-Year Review Guidance. EPA 540-R-01-007.June.


v-/

TABLES

030945 Final EATS 5-Yr Rw/ Rptdoc


030945 Final EATS 5-Yr Rvw RpLdoc

Page 1 of 1TABLE 2-1

CHRONOLOGY OF OPERABLE UNIT 5

Event

Initial discovery of contamination, Initial Assessment Study

Confirmation Study at Moffett Field

Moffett placed on the National Priorities List

Federal Facility Agreement signed

Final Remedial Investigation (RI) Report completed

Base operations transferred to NASA

Final Feasibility Study (FS) Report completed

OU 5 ROD signed

Remedial Design started

Remedial Design completed

EATS construction started

Final EATS Long-Term Groundwater Monitoring Plan completed

EATS completed/operation and maintenance begins

Groundwater monitoring begins

EATS operating properly and successfully

MOA signed between DoN and NASA for institutional controls at OUs 1 and 5

Final EATS Operations and Maintenance Manual completed

Final EATS Interim Remedial Action Report completed

EPA approval of Final EATS Interim Remedial Action Report

EATS groundwater extraction and treatment

Groundwater monitoring

Date

March 1984

April 1986

July 1987

August 1990

August 1993

July 1994

August 1995

June 1996

April 1996

May 1997

July 1997

July 1997

January 1999

March 1999

May 1999

November 1999

September 2000

May 2001

November 2001

Ongoing

Ongoing


DoN - Department of NavyEATS - East-Side Aquifer Treatment SystemFS - Feasibility StudyMOA Memorandum of AgreementNASA National Aeronautics and Space AdministrationOU - Operable UnitRI - Remedial InvestigationROD - Record of Decision

030945 Final BATS 5-Yr Rvw Rpl.doc


030945 Final EATS 5-Yr Rv\v Rpl.doc

Page 1 of 1

TABLE 3-1

HYDROSTRATIGRAPHY

Unit

A

Unit Subdivision

Al aquifer zone

A1/A2 aquitard

A2 aquifer zone

A/B aquitard

Range of Approximate Depths(ftbgs)

Top

Oto 13

Discontinuous

15 to 45

45 to 65

Bottom

15 to 35

Discontinuous

45 to 77

60 to 85


ft bgs - feet below ground surface

0309« Final EATS 5-Yr Rvw Rptdoc


030945 Final EATS 5-Vr Rvw RpLdoc

TABLE 3-2

COMPARISON OF 1,1-DCE, 1,2-DCA, CIS-1,2-DCE, PCE, TCE AND VC CONCENTRATIONSBASELINE YEAR (1998) VS. 2002

Page 1 ofl

Well

I.D."

WU5-4 (N)WU5-5

WU5-8 (N)WU5-10WU5-14WU5-16WU5-17WU5-18WU5-19WU5-20WU5-21WU5-22WU5-23WU5-24WU5-25EXW-1EXW-2EXW-3EXW-4EXW-5

1,3-OCE

1998"

fag/D0.5 U0.5 U0.5 U0.5 U0.5 U0.5 U0.5 U

0.5 U/ 0.5 U0.5 U0.5 U0.5 U0.5 U0.5 U

0.6/0.60.5 U0.8

0.5 U/ 0.5 U0.5 U

30.5 U

1,1-DCE

2002*-*

(Hg/L)2 U21)2U0.5 J2U2 U2U2 U2U2 U2 U2U2U0.4 J2U0.6 J2 U2U0.8 J2 U

1,2-DCA

1998*

(Hg/L)0.5 U0.5 U0-5 U0.5 U0.5 U0.5 U0.5 U

0.5 U/ 0.60.62

0.5 U0.5 U0.5 U

0.5 U/ 0.5 U0.5 U0.5 U

0.5 U / 0.5 U0.5 U0.5 U0.5 U

1,2-DCA

2002C

(Hg/L)0.5 U0.5 U0.5 U0.5 U0.5 U0.5 U0.5 U0.5

0.3 J0.5 U0.5 U0.5 U0.5 U0.5 U0.6

0.5 U0.5 U0.5 U0.5 U0.6

cis-l,2-DCE

1998b

QvM0.5 U

80.5 U0.70.7

11

28/3039409

0.5 U12

6/8 UJ389

2 / 279

49 D

cis-l,2-DCE2002"

(Hg^)2U2J

0.3 J1 J

0.9 J0.9 J0.7 J

1611H

0.9 J0.5 J

31015111 J51311

PCE

1998"(Hg/L)0.5 U0.5 U0.5 U0.5 U0.5 U

52

1 / 122

0.60.5 U

362D/64D

0.988 D6 /6

70.5 U

4

PCE2002Clt

(fg/L)2U2U2 U2U0.5 J

43

0.8 JU

0.5 J0.3 J2U2J40

0.8 J5455

1 J2J

TCE

1998b

0«g/L)110.9217341817

4/3421

0.5 U3

36/38335

32/32825

TCE2002C

(Hg/L)14

0.5 J2J19512618541 J

0.6 J1 J23022633843

VC1998b

(Hg/L)0.5 U0.5 U0.5 U0.5 U0.5 U0.5 U0.5 U

0.8 / 0.80.96

0.80.5 U

20.5 U / 0.5 U

10.6

0.5 U/ 0.5 U4

0.53

VC2002C'U

(Mg/L)0.5 U0.5 U0.5 U0.5 U0.5 U0.5 U0.5 U0.5

0.5 U0.5 U0.5 U0.5 U0.5 U0.5 U0.3 J0.8

0.5 U22

0.7

a - The following monitoring wells were sampled in 2002, but are not included in this table because they were not sampled in the baseline year (1998): WSW-5, WSW-6. WT2-1, WT55-1, WU5-1, WU5-9 (N), WU5-II, WU5-12, WU5-13,

W3-I, W4-1, W4-2, W4-3, W4-6, W4-11, W4-I3, W4-14, W4-IS, W4-I6, W5-S, W5-I7, WS-23, W5-2S, W6-2, W7-10, W19-2, and W43-3.

b - Baseline data. Results from November 1998 sampling event,

c - Results from November 2002 sampling event

d - The maximum concentration of I, I-DCE delected in a monitoring well during the 2002 sampling event was 0.8J ug/L in well W3-1.

e - The maximum concentration of cis-l,2-DCE detected in a monitoring well during the 2002 sampling event was 19 ug/L in well WU5-1.

f - The maximum concentration of PCE detected in a monitoring well during the 2002 sampling event was 44 ug/L in well W7-10.

g - The maximum concentration of vinyl chloride detected in a monitoring well during the 2002 sampling event was 4 ug/L in well WSW-5.

Abbreviations anil Acronyms:

1,1-DCE- 1,1-dichloroethene ug/L - micrograms per liter

1,2-DCA -1.2-diclilorocthane 28 / 30 - Primary and duplicate sample results

cis-i ,2-DCE - cis-1,2-dic)iloroEll>cnc U - Not detected

PCE - letrachloroctlicne j - Estimated data

TCE - trichlorocthene UJ - Estimated non-detect result

VC - vinyl chloride O - Diluted sample

(N) - Northern Plume groundwater monitoring well. All others arc Southern Plume,

030945 Foul EATS S-Vr Kvw R|H ToWc 3-2.xls/Tablc 3-2

Page 1 of 1

TABLE 4-1

EATS ANNUAL OPERATIONAL DATA

ReportingPeriod

19992000

2001

2002

Totals

PercentOperational

90%

98%

99%

94%

Total Flow(gallons) a'b

12,800,000

15,740,000

15,030,000

15,750,000

59,320,000

ContaminantMass Removed

(lbs)c

5.0

5.9

5.2

5.4

21.5

Mass Removed PerMillion Gallons

(Ib/Mgal)

0.39

0.37

0.34

0.34

0.36

Notes:a Cumulative flow is based upon the system flow meter.b Total flow numbers have been rounded to the nearest 10,000 gallon.c Contaminant mass removed is based upon the four primary contaminants of concern, vinyl chloride (VC),

tetrachloroethene (PCE), trichloroethene (TCE), and cis-l,2-dichloroethene (cis-l,2-DCE), whichtypically represent 98+ percent of volatile organic compounds (VOCs) detected.

TABLE 4-2

EATS ANNUAL SYSTEM O&M COSTS

Dates

From

October 1999

January 2000

January 2001

January 2002

Through

December 1999

December 2000

December 2001

December 2002

ReportedCost

($l,000s)a

$4

$112

$260

$182

AnnualizedCost

($l,000s)a

$18

$112

$260

$182

Annual PercentChange

~510

130

-30

Notes:a Reported costs have been rounded to the nearest $ 1,000s.

03094i Final EATS 5-Vr Rwr Rpl Tables J-l and 4-J.tloc


0309J5 Fiiul EATS 5-Vr RTO Rp.ljoc

FIGURES

030945 Final EATS 5-Yr Rvw Rpt.doc


030945 Final EATS 5-Yr Rvw Rpl.doc

FORMER NASMOFFETT FIELD

LEGEND

fT)— STATE HIGHWAY

US HIGHWAY

INTERSTATE HIGHWAY

FORMER NAS MOFFETT FIELD

| | WATER

10

Miles

Scale: 1" = 10 MilesDATUM: HORIZONTAL - NAD83, VERTICAL - NGVD29

9a

BASE REALIGNMENT AND CLOSUREPROGRAM MANAGEMENT OFFICE WEST

SAN DIEGO, CAFIGURE 1-1

REGIONAL LOCATION MAP

FORMER.NAS MOFFETT FIELDMOFFETT FIELD, CA

TETRA TECH F-W. INC.

LEGEND

INSTALLATION RESTORATION SITES

SITE 1 RUNWAY LANDFILL

SITE 2 FORMER GOLF COURSE LANDFILL

SITE 22 GOLF COURSE LANDFILL No. 2

SITE 25 EASTERN DIKED MARSH ANDSTORMWATER RETENTION BASIN

SITE 26 EAST-SIDE AQUIFER TREATMENT SYSTEM(EATS)

SITE 27 NORTHERN CHANNEL

SITE 28 WEST-SIDE AQUIFERS TREATMENTSYSTEM (WATS)

FORMER NAS MOFFETT FIELD BOUNDARY

1000' 0 1000' 2000'

SCALE: 1" = 2000'

NAVAL FACILITIES ENGINEERING COMMANDSOUTHWEST DIVISION

SAN DIEGO. CA

FIGURE 1-2SITE LOCATION MAP

FORMER NAS MOFFETT FIELDMOFFETT FIELD, CA

TETRA TECH FW, INC.

o

3o>

3

I

3

£

8

?i

4

4+ + + +

+ + -F- + +

+ + 4- +

+ + 4- + +

4 - 4 - 4

+ + 4- 4- +

+.• + + +

LEGENDEXW-1 EXTRACTION WELL

• TREATMENT SYSTEM

E3 APPROX. EXTENT OF NORTHERNVOC GROUNDWATER PLUME*

ES3 APPROX. EXTENT OF SOUTHERNVOC GROUNDWATER PLUME*

*AS SHOWN IN OU5 ROD.

REFERENCES: DON, 1996

250* 0 250* 500'

SCALE: 1" = 500'

GENERAL REGIONALGROUNDWATER

FLOW DIRECTION


SAN DIEGO. CAFIGURE 3-1

EATS LOCATION AND APPROXIMATEEXTENT OF VOC PLUMES IN 1996


TETRA TECH FW, INC.

V

.LEGEND4" EXW-1 EXTRACTION WELL

• TREATMENT SYSTEM+ + +i]r/^ APPROX. EXTENT OF NORTHERN

VOC GROUNDWATER PLUME, DECEMBER 2002APPROX. EXTENT OF SOUTHERNVOC GROUNDWATER PLUME, DECEMBER 2002

REFERENCES: TtFW, 2004

250' 0 250' 500'I I I ISCALE: 1" = 500'


FLOW DIRECTION



EATS LOCATION AND APPROXIMATEEXTENT OF VOC PLUMES IN 2002


TETRA TECH FW, INC.

a

i-O

Z O

Iso

_

Se

otoo

(O *~m

fg

LEGEND

^.W9-8 WELL NAME

^.EXW-4' EXTRACTION WELL NAME

250' 0 250' 500'I I I ISCALE: 1" = 500'


FLOW DIRECTION



LOCATION OF EATS EXTRACTION WELLSAND MONITORING WELLS

(ENLARGEMENT OF AREA EAST OF THE RUNWAYS)FORMER NAS MOFFETT FIELD

MOFFETT FIELD, CA

TETRA TECH FW, INC.

100

0.1

0.1

FIGURE 3-4TIME SERIES OF TCE CONCENTRATIONS

Figure 3-4A Figure 3-4B

Date SampledFigure 3-4C

Date SampledFigure 3-4D

Notes: TCE - Trichloroethene. Date SamPled

Wells shown in graphs are screened in the A1 aquifer zone. jig/L -microgramsper liter.Open symbols indicate n on-detects, with concentrations 1/2 of reporting limits. Closed-colored symbols indicate concentration detected.

Date Sampled

1000

FIGURE 3-5TIME SERIES OF PCE CONCENTRATIONS



Date Sampled

Figure 3-5D

Notes: PCE - Tetrachloroethene. Date SamPled

Wells shown in graphs are screened in the A1 aquifer zone. |Lg/L - micro grams per liter.Open symbols indicate non-detects, with concentrations 1/2 of reporting limits. Closed-colored symbols indicate concentration detected.

Date Sampled

FIGURE 3-6TIME SERIES OF CIS-1,2-DCE CONCENTRATIONS




Date SampledNotes: CIS-1,2-DCE - Cis-1 ,2-Dichloroethene.Wells shown in graphs are screened in the Al aquifer zone. (ig/L - microgramsper liter.Ooen svmbols indicate non-detects. wkh concentrations 1II of reoortine limits. Closed-colored symbols indicate concentration detected.

Date Sampled

0.1

100

FIGURE 3-7TIME SERIES OF VINYL CHLORIDE CONCENTRATIONS


Date Sampled

Figure 3-7CDate Sampled

Figure 3-7D

Date SampledNotes:Wells shown in graphs are screened in the A1 aquifer zone. jig/L -microgramsper liter.Onen svmbols indicate non-detects. with concentrations 1II of reoortina limits. Closed-colored svmbols indicate concentration detected.

Date Sampled

FIGURE 3-8TIME SERIES OF 1,1-DCE CONCENTRATIONS

Figure 3-8A Figure 3-8B100

10

§

0.1 0.1

EATS 6n-Line

Date SanpledFigure 3-8C

Date SaiqpledFigure 3-8D

o.i

Date SampledNotes: 1,1-DCE -1,1 -Dichloroethene.Wells shown in graphs ate screened in the A1 aquifer zone. |ig/L -microgramsper liter.Ooen symbols indicate non-detects. with concentrations 1/2 of reoortine limits. Closed-colored svmbols indicate concentration detected.

Date Sampled

cFIGURE 3-9

TIME SERIES OF 1,2-DCA CONCENTRATIONS


0.1

Date Sampled

Figure 3-9C


100

y™s

M 10 -

1§a

0.1

EATS On-Line

§

0.1

Date SampledNotes: 1,2-DCA - 1,2-DichlotoethaneWells shown in graphs are screened in the A1 aquifer zone. |j,g/L -microgramsper liter.Ooen symbols indicate non-detects. with concentrations 112 of reoortins limits. Closed<olored svmbols indicate concentration detected.

Date Sampled

eno

8

i

3

£Q

1

I

q

go

"

I Q-

II

FROM WEU EXW-1

FROM WELL EXW-2

FROM WELL EXW-3

FROM WELL EXW-4

LFROM WELL EXW-5

FROM ATMOSPHERE

(TYPICAL OF IALL WELLS) I

F-102AIR STRIPPER

BLOWER INLET FILTERB-103

AIR STRIPPERBLOWER

SECONDARY CONTAINMENTSUMP PUMP

F-107A F-107B F-107C

P-104AIR STRIPPER

TRANSFER PUMPF-107 A/B/C/0

GAC INFLUENTFILTERS

(EXISTING SITE 9SCM BAG FILTERS)

SECONDARY CONTAINMENT

F-107D

- SP3

v-ioa V-109

T i ISP4 i SP5

LIQUID- PHASEGAC BEDS

(EXISTING SITE 9 SCM GAC BEDS)

GAC BED DRAINAGE

DISCHARGE

REFERENCE: TTEMI, 2000a


SAN DIEGO. CA

FIGURE 4-1PROCESS FLOW DIAGRAM


TETRA TECH FW. INC.

FIGURE 4-2EATS CUMULATIVE CONTAMINANT MASS REMOVED AND

CUMULATIVE VOLUME OF WATER TREATED

70,000,000

Year End - December 200259,317,330 gallons (gals)21.47 pounds (Ibs)

30,000,000 a»

Cumulative Contaminant Removed (Ibs)

Cumulative Volume Treated (gals)

10,000,000

0.00

Jan-99 May-99 Sep-99 Jan-00 May-00 Sep-00 Jan-01 May-01 Sep-01 Jan-02 May-02 Sep-02 Jan-03Note: TimeTotal mass removed is based on concentrationsof TCE, PCE, cis-l,2-DCE, and VC.

c

2,500,000.0

2,300,000.0

5^2,100,000.0

1 1,900,000.0

IS)a 1,700,000.0o

s1,500,000.0£ »,-/!/«,'

o

1,300,000.0

,1/3

g 1,100,000.0

"5900,000.0

700,000.0

500,000.0

FIGURE 4-3

EATS CONTAMINANT REMOVAL RATE COST

Cost Reflects

System Upgrade

Monthly Flow (gals)Cost per Pound Removed ($/lb)Linear (Monthly Flow (gals))Linear (Cost per Pound Removed ($/lb))

$200,000

-- $150,000

$100,000

u

1I+*aa•CM

S5ao

- $50,000

Dec-99 Feb-00 May-00 Aug-00 Nov-00 Feb-01 May-01 Aug-01 Nov-01 Feb-02 May-02 Aug-02 Nov-02

Time

APPENDIX A

DOCUMENT REVIEW LIST




APPENDIX A

DOCUMENT REVIEW LIST

California Code of Regulation, Title 27.

Department of the Navy (DoN). 1996. Final Station-Wide Remedial Investigation Report.May 21.

. 1996. Moffett Federal Airfield Final Operable Unit 5 Record ofDecision, Moffett Federal Airfield, California. June 28.

. 2001. Guidance for Optimizing Remedial Action Operation.November 29.

. 2001. Policy for Conducting Comprehensive Environmental Response,Compensation, and Liability Act (CERCLA) Statutory Five-Year Reviews. November.

Foster Wheeler Environmental Corporation (FWENC). 2001. Final Site-Specific ContractorQuality Control Plan, Moffett Federal Airfield, Moffett Field, California.

. 2002. Final First Annual Groundwater Report for WATS and EATS,Moffett Federal Airfield, Moffett Field, California.

. 2002. Draft 2001 Annual Groundwater Report for WATS and EATS,Moffett Federal Airfield, Moffett Field, California. May 28.

. 2002. Draft EATS Evaluation Work Plan. Moffett Federal Airfield,Moffett Field, California. September.

International Technology Corporation (IT). 1991. Phase I Characterization Report, Naval AirStation, Moffett Field, California. Volumes 1 through 5. April.

Iwamura, T.I. 1980. Saltwater Intrusion Investigation in the Santa Clara County Bay lands Area,California. Unpublished Report of Santa Clara Valley Water District.

National Aeronautics and Space Administration (NASA). 1994. Moffett Field ComprehensiveUse Plan. Moffett Field, California. September.

PRC Environmental Management, Inc. (PRC). 1995. Draft Final Operable Unit 5 FeasibilityStudy Report, Volume I; Moffett Federal Airfield, California. August 31.

. 1997. East-Side Aquifer Treatment System Final Long-TermGroundwater Monitoring Plan. Moffett Federal Airfield, California. July 3.

Regional Water Quality Control Board (RWQCB). 1995. San Francisco Bay Basin WaterQuality Control Plan.

030945 Final EATS 5-Yr RwiRpt.doc A.I

State Water Resources Control Board (SWRCB). 1998. Resolution No. 88-63, Adoption ofPolicy entitled "Sources of Drinking Water." May.

Tetra Tech EM, Inc. (TtEMI). 1997. Final Quality Assurance Project Plan for Long-TermGroundyvater Monitoring. Moffett Federal Airfield, California. October 31.

. 2000. East-Side Aquifer Treatment System Final Operation andMaintenance Manual. September 29.

_. 2001. Draft Final Interim Remedial Action Report, East-Side AquiferTreatment System (EATS). May 18.

_. 2001. Draft Final Interim Remedial Action Report for Site 1 and Site 2Landfill Closure. Moffett Federal Airfield, Moffett Field, California. September 25.

U.S. Environmental Protection Agency (EPA). 1996. Pump-and-Treat Ground-WaterRemediation, A Guide for Decision Makers and Practitioners. EPA 625-R-95-005. July.

. 2001. Comprehensive Five-Year Review Guidance. EPA 540-R-01-007.June.

030945 Final EATS S-Yr Rvw Rpldoc A.2

APPENDIX B

FIVE-YEAR REVIEW INSPECTION FORM

030945 Final EATS S-Yr Rvw Rpt.doc



EATS Five-Year Review Site Inspection Checklist

I. SITE INFORMATION

Site name:East-Side Aquifers Treatment System (EATS)

Location and Region:Moffett Federal AirfieldMoffett Field, CaliforniaEPA Region 9

Agency, office, or company leading the five-yearreview:

Southwest DivisionNaval Facilities Engineering Command1220 Pacific HighwaySan Diego, California 92132-5190

Date of inspection:August 6, 2002

EPA ID:CA2170090078

Weather/temperature:Clear Skies74°F Daytime High57°F Nighttime Low

Remedy Includes: (Check all that apply)(~1 Landfill cover/containmentI I Access controlsI I Institutional controls£<] Groundwater pump and treatmentfl Surface water collection and treatmentD Other

[~| Monitored natural attenuationI I Groundwater containmentl~~l Vertical barrier walls

Attachments: [ Inspection team roster attached I I Site map attached

030945 Final EATS 5-Yr Rvw Rpt App B.doc

. ON-SITE DOCUMENTS & RECORDS VERIFIED (Check all that apply)

1. O&M DocumentsE3 O&lyl manual [3 Readily available gj Up to date [UN/A[X] As-built drawings £<] Readily available ^1 Up to date d N/A£<] Maintenance logs ^ Readily available SUptodate dN/ARemarks): O&M Manual dated August 18,2000 by TtEMI with record drawings in Attachment A ofVol. 1. Weekly and monthly inspection logs (paper and electronic).

2. Site-Specific Health and Safety Plan £<] Readily available £3 Up to date D N/AIxl Contingency/emergency response plan IXI Readily available l~l Up to date |~| N/ARemarks; Base-Wide H&S Plan dated August 8, 2001 with Section 12 dedicated to emergencyresponse plans.

3. O&M and OSHA Training Records [X] Readily available ^ Up to date ON/ARemarks; Records for all onsite personnel maintained for 40-hr HAZWOPER, 8-hr refresher,LockoutfTagout, Confined Space Entry, OSHA Site Supervisor, DOT Transportation, HAZMAT,Competejnt Person Excavation Certification and First Aid / CPR.

4. Permits and Service Agreements[3 Air discharge permit 1X1 Readily available £3 Up to date I I N/A[3 Effluent discharge K! Readily available [X] Up to date D N/Ad Waste disposal, POTW D Readily available d Up to date [El N/An Other permits D Readily available d Up to date [X] N/ARemarks: Air - BAAQMD exemption letter dated May 30, 1997.Water - KPDES general permit CAG912003, Order No. 99-051 with authorization letter datedNovember 21, 2001. This permit was subsequently amended via letter dated April 30, 2002.

5. Gas Generation Records d Readily available f~] Up to date [>3 N/ARemarks; Per the BAAQMD air permit, air discharge compliance is maintained through influent andeffluent Samples of the treated ground water.

6. Settlement Monument Records l~1 Readily available F~l Up to date £3 N/ARemarks:

7. Groundtvater Monitoring Records ^ Readily available £<] Up to date CD N/ARemarks; 2000 and 2001 Annual Groundwater Monitoring reports, in addition to the quarterlygauging events (Black Thursday) field forms and electronic files

Leachate Extraction Records [D Readily available d Up to date ^ N/ARemarks;

9. Discharge Compliance RecordsOAir D Readily available Q Up to date £<JN/A13 Water (effluent) Kl Readily available 13 Up to date Q N/ARemarks: 1st and 2nd Quarter 2002 and 2001 Annual NPDES Self-Monitoring Reports

10. Daily Access/Security Logs IEI Readily available ^ Up to dateRemarks: Daily On-Site Logs and Daily Briefing Sign-In sheets are maintained in the site trailer.


ra. O&M COSTSO&M Organization[~| State in-houseD PRP in-houseO Federal Facility in-houseD OtherRemarks: FWENC is current O&M contractor. IT Corp and TtEMI were previous O&M contractors.

[~] Contractor for StateD Contractor for PRP^ Contractor for Federal Facility

O&M Cost Records£<] Readily available El Up to dateE3 Funding mechanism/agreement in placeOriginal O&M cost estimate Not Available O Breakdown attached

Total annual cost by year for review period if available

From Jan 2000 To Dec 2000 $112kDate Date Total cost

From Jan 2001 To Dec 2001 $260kDate Date Total cost

From Jan 2002 To June 2002 $115k

From

From

Date

Date

Date

To

To

Date

Date

Date

Total cost

Total cost

Total cost

Breakdown attached

Breakdown attached

I I Breakdown attached

Breakdown attached

Breakdown attached

Remarks: EATS operation began January 26, 2000. IT Corp. and TtEMI cost basis differentfrom t h e FWENC basis. - - - - - - - : - . - - -

Unanticipated or Unusually High O&M Costs During Review PeriodDescribe costs and reasons: No significant cost increases have been observed.


IV. ACCESS AND INSTITUTIONAL CONTROLS g] Applicable D N/A

A. Fencing

1. Fencing damaged |~] Location shown on site map IX) Gates secured l~l N/ARemark$: Fencing around treatment system is in excellent condition with locked gate. Securityaround fyase 24-hr through controlled access areas.

B. Other Access Restrictions

1. Signs aijid other security measures C3 Location shown on site map |~|N/ARemarks: Security around Federal facility is manned 24-hr/day and seven days/week, with gatedand controlled access roads.

C. Institutional Controls (ICs)

1. Implementation and enforcementSite conditions imply ICs not properly implemented O Yes 03 No l~| N/ASite conditions imply ICs not being fully enforced [~1 Yes |^ No f~l N/A

Type of monitoring (e.g., self-reporting, drive by): Unofficial drive by from Navy contractorFrequency: MonthlyResponsible party/agency: Not ApplicableContact: Not Available

Name Title Date Phone no.

Reporting is up-to-date D Yes QNo £3 N/AReports $re verified by the lead agency O Yes C] No 03 N/A

Specific requirements in deed or decision documents have been met [~1 Yes d) No ^ N/AViolations have been reported f~l Yes CH No 13 N/AOther problems or suggestions: Q Report attachedThe primary 1C is the continuous operation of the Building 191 sump. The sump is controlled andoperated by a third party (NASA) as part of the FFA. Navy or Navy contractor has no responsibilityover sunip operation.

2. Adequacy E*3 ICs are adequate f~| ICs are inadequate Q N/ARemarks', Based upon groundwater capture analysis presented in the 2001 Annual Report.

D. General

1. Vandalism/trespassing [~1 Location shown on site map ^ No vandalism evidentRemarks:

2. Land use changes on site £<] N/ARemarks:

3. Land use changes off site ^ N/ARemarks:

030945 Final EATS 5-Yr Rvw R$t App B.doc

V. GENERAL SITE CONDITIONS

A. Roads IE1 Applicable D N/A

1. Roads damaged [H Location shown on site map £3 Roads adequate l"~l N/ARemarks: Roads around treatment systems and extraction wells paved and in good condition.

B. Other Site Conditions

Remarks: Base is still an active Federal facility and is well maintained.


VI. LANDFILL COVERS Q Applicable

A. Landfill Surface

1. Settlement (Low spots)Areal extentRemarks:

Q Location shown on site mapDepth

| Settlement not evident

2. CracksLengths__Remarks:

[~1 Location shown on site map I I Cracking not evidentWidths Depths

ErosionAreal extent_Remarks:

Q Location shown on site map d Erosion not evidentDepth

HolesAreal extent_Remarks.:

[~l Location shown on site map l~~l Holes not evidentDepth

Vegetative Cover

Remarks:

| Grass Q Cover properly established Q No signs of stress| Trees/Shrubs (indicate size and locations on a diagram)

Alternative Cover (armored rock, concrete, etc.)Remarks:

DN/A

BulgesAreal extent_Remarks:

Q Location shown on site map [~l Bulges not evidentHeight

Wet Areas/Water DamageG Wet areasCH PondingLH Seepsd Soft subgradeRemarks:

I I Wet areas/water damage not evidentI I Location shown on site map Areal extent_[~l Location shown on site map Areal extent_I I Location shown on site map Areal extent_Q Location shown on site map Areal extent_

9. Slope Instability Q Slides CD Location shown on site map Q No evidence of slope instabilityAreal extentRemarks:

B. Benches D Applicable(Horizontally constructed mounds of earth placed across a steep landfill side slope to interrupt the slopein order to slow down the velocity of surface runoff and intercept and convey the runoff to a linedchannel.)

030945 Final EATS S-Yr Rvw Rpt App B.doc

1. Flows Bypass BenchRemarks:

Location shown on site map [~| N/A or okay

2. Bench BreachedRemarks:

[~| Location shown on site map [~l N/A or okay

3. Bench OvertoppedRemarks:

| Location shown on site map N/A or okay

C. Letdown Channels [~1 Applicable Q N/A(Channel lined with erosion control mats, riprap, grout bags, or gabions that descend down the steep sideslope of the cover and will allow the runoff water collected by the benches to move off of the landfillcover without creating erosion gullies.)

1. SettlementAreal extent_Remarks:

Location shown on site map [~1 No evidence of settlementDepth

2. Material Degradation Q Location shown on site map Q No evidence of degradationMaterial type Areal extentRemarks:


I I Location shown on site map_ Depth _

I I No evidence of erosion

UndercuttingAreal extentRemarks:

I I Location shown on site map_ Depth _

l~l No evidence of undercutting

5. Obstructions Type_ No obstructionsI I Location shown on site mapRemarks:

Areal extent Size

6. Type_Excessive Vegetative GrowthI I No evidence of excessive growthl~~l Vegetation in channels does not obstruct flowI I Location shown on site mapRemarks:

Areal extent

D. Cover Penetrations E] Applicable Q N/A

1. Gas Vents d Activel~~| Properly secured/locked Q Functioning[~~| Evidence of leakage at penetrationDN/ARemarks:

Passivel Routinely sampledNeeds Maintenance

Good condition


2. Gas Monitoring ProbesCH Properly secured/locked d Functioning l~l Routinely sampled |~| Good conditionQ Evi4ence of leakage at penetration |~) Needs Maintenance l~l N/ARemarks:

3. Monitoring Wells (within surface area of landfill)|~1 Propjerly secured/locked I I Functioning I \ Routinely sampledCD Evidence of leakage at penetration |~| Needs MaintenanceRemark^.

| Good conditionIN/A

4. Leachate Extraction WellsCH Propjerly secured/locked [~1 Functioning f~| Routinely sampled [~1 Good conditiondl Evidence of leakage at penetration l~] Needs Maintenance l~l N/ARemarks:

5. Settlement MonumentsRemarks:

Located l~l Routinely surveyed fl N/A

E. Gas Collecticjn and Treatment D Applicable Q N/A

1. Gas Treatment FacilitiesI | Flarijig I I Thermal destruction|~| Good condition l~"l Needs MaintenanceRemarks:

[ Collection for reuse

2. Gas Collection Wells, Manifolds and Piping[~| Good condition O Needs MaintenanceRemarks::

3. Gas Monitoring Facilities (e.g., gas monitoring of adjacent homes or buildings)I | Good condition I I Needs Maintenance I I N/ARemarks;

F. Cover Drainage Layer dl Applicable DN/A1. Outlet Pfpes Inspected

Remarks:Functioning DN/A

2. Outlet Rock InspectedRemarks:

[U Functioning DN/A

G. Detention/Sedimentation Ponds d Applicable DN/A1. Siltation Areal extent_

I I Siltation not evidentRemarks:

Depth_ DN/A

030945 Final BATS 5-Yr Rvw Rpt App B.doc

2. ErosionRemarks:

Areal extent Depth_ Erosion not evident

3. Outlet WorksRemarks:

C] Functioning |~1 N/A

4. DamRemarks:

O Functioning Q N/A

H. Retaining Walls D Applicable Q N/A

1. Deformations dj Location shown on site map [3 Deformation not evidentHorizontal displacement Vertical displacementRotational displacementRemarks:

2. DegradationRemarks:

C] Location shown on site map Q Degradation not evident

I. Perimeter Ditches/Off-Site Discharge D Applicable Q N/A

1. SiltationAreal extent_Remarks:

Location shown on site mapDepth _

Siltation not evident

Vegetative Growth d| Location shown on site mapO Vegetation does not impede flowAreal extent TypeRemarks:

DN/A


[~~1 Location shown on site map I I Erosion not evidentDepth_

4. Discharge StructureRemarks:

Functioning C] N/A


VH. VERTICAL BARRIER WALLS Q Applicable

1. Settlement [H Location shown on site map f~l Settlement not evidentAreal extent DepthRemark?:

2. Perfornjiance Monitoring Type of monitoringl~l Performance not monitoredFrequenpy Q Evidence of breachingHead differentialRemark^:

030945 Final EATS 5-Yr RwK Rpt App B.doc

VIII. GROUNDWATER/SURFACi; WATER REMEDIES IEI Applicable QN/A

A. Groundwater Extraction Wells, Pumps, and Pipelines £3 Applicable Q N/A

1. Pumps, Wellhead Plumbing, and Electrical1X1 Good condition ^ All required wells properly operating I~I Needs Maintenance d] N/ARemarks: All visible piping, instruments, electrical connections, and enclosures in good conditions(most components stainless steel).

2. Extraction System Pipelines, Valves, Valve Boxes, and Other AppurtenancesIXJ Good condition |~l Needs MaintenanceRemarks: The majority of the HDPE extraction system pipeline is buried / not visible. Visibleconnections at well vaults and treatment system show no signs of cracks or discoloration. Well vaultsin excellent condition; covers do not have gaskets, so no concern for gasket replacement.

3. Spare Parts and Equipment1X3 Readily available 1X1 Good condition d Requires upgrade l~l Needs to be providedRemarks: Plenty of piping component spare parts.

B. Surface Water Collection Structures, Pumps, and Pipelines ^ Applicable Q N/A

1. Collection Structures, Pumps, and ElectricalIX) Good condition [~1 Needs MaintenanceRemarks: Includes only the sump and pump at the treatment pad. Sump is clean and pump andcontrols in good order.

2. Surface Water Collection System Pipelines, Valves, Valve Boxes, and Other Appurtenances[XI Good condition l~l Needs MaintenanceRemarks: Significant discoloration of Sch. 80 PVC piping but no cracks. Will need maintenance inthe near future or replacement in 2-4 years.

3. Spare Parts and Equipment1X3 Readily available 1X1 Good condition I I Requires upgrade I I Needs to be providedRemarks: Multiple vendors available.for parts, with short delivery time frames.

C. Treatment System |X] Applicable QN/A

1. Treatment Train (Check components that apply)I I Metals removal I I Oil/water separation [~~| Bioremediation1X1 Air stripping IXI Carbon adsorbers[XJ Filters: Multiple Sock Filters1X1 Additive (e.g., chelation agent, flocculent): Anti-sealant agentsI I Others: Advanced Oxidation Process (AOP) - ozone and peroxide oxidation systemIXI Good condition CD Needs Maintenance1X1 Sampling ports properly marked and functional1X1 Sampling/maintenance log displayed and up to date1X3 Equipment properly identified:[X] Quantity of groundwater treated annually: 15 million gallonsl~l Quantity of surface water treated annually: Not applicable since only limited water collectedfrom treatment pad sump.Remarks: Significant discoloration of Sch. 80 PVC piping but no cracks. Will need maintenance inthe near future or replacement in 2-4 years.


2.

3.

4.

5.

6.

D.1.

2.

D.

1.

Electrical Enclosures and Panels (properly rated and functional)CH N/A' [>3 Good condition [H Needs MaintenanceRemarks: Most enclosures stainless steel and in excellent condition, exception is motor control panel,Transfofmer and electrical service panel which will need painting. Gaskets on enclosures in goodconditiotn but will need replacement in 3-5 years.

Tanks, Vaults, Storage Vessels[~] N/A ^ Good condition £2 Proper secondary containmentRemark$:

Discharge Structure and Appurtenances] 1 N/A £3 Good condition 1~| Needs MaintenanceRemark^ :

O Needs Maintenance

Treatment Building(s)ON/A 13 Good condition (esp. roof and doorways) D Needs repair1X1 Cherpicals and equipment properly storedRemarks: No storage drums evident. Secondary containment around treatment units in good order.Limited tools and miscellaneous supplies stored in treatment areas. No evidence of weeds or otherintrusive plants. Equipment and treatment pads washed down.

Monitoring Wells (pump and treatment remedy)P<3 Properly secured/locked ^ Functioning E3 Routinely sampled|~1 All required wells located CH Needs MaintenanceRemarks: Not all wells located due to the number of wells («1500 wells)

Monitoring DataMonitorijag Data[3 Is routinely submitted on time 13 Is of acceptable quality

^ Good conditionON/A

Monitoring data suggests:[X] Grouridwater plume is effectively contained 1 1 Contaminant concentrations are decliningRemarks: Based upon 2001 Annual Report

Monitored Natural Attenuation

Monitoring Wells (natural attenuation remedy)1 1 Properly secured/locked [H Functioning CH Routinely sampled!~1 All required wells located CD Needs MaintenanceRemarks:

~~| Good condition§3 N/A


IX. OTHER REMEDIES Q Applicable

If there are remedies applied at the site which are not covered above, attach an inspection sheet describingthe physical nature and condition of any facility associated with the remedy. An example would be soilvapor extraction.


X. OVERALL OBSERVATIONS

A. Implementation of the Remedy

Describe issues and observations relating to whether the remedy is effective and functioning as designed.Begin w|ith a brief statement of what the remedy is to accomplish (i.e., to contain contaminant plume,minimizie infiltration and gas emission, etc.).

The rerqedy is to prevent migration of the contaminant plume and restore groundwater to drinking waterstandards. The remedy is providing capture as designed, but is not reducing groundwater plume size orcontaminant concentrations. The air stripper and GAC effectively remove contaminants from extractedgroundwater prior to discharge so that NPDES requirements are met. The remedy has reachedasymptotic levels for extraction rates of contaminants and is providing declining value, based upontreatment system costs per Ib of contaminant removed.

B. Adequacy of O&M

Describe, issues and observations related to the implementation and scope of O&M procedures. Inparticulajr, discuss their relationship to the current and long-term protectiveness of the remedy.

The implementation and scope of O&M procedures are more than adequate to ensure the current andlong-term protectiveness of the remedy. The O&M procedures include ample monitoring procedures(i.e. morithly treatment system influent / effluent samples, yearly groundwater samples and plumedelineation, and predictive/preventative maintenance programs). Operating staff also is present 5 days aweek throughout the year, and the treatment system contains electronic instrumentation with computercontrol that provides automatic shutdown and alarming off site, if necessary, to ensure proper operation.

C. Early Indicators of Potential Remedy Problems

Describe issues and observations such as unexpected changes in the cost or scope of O&M or a highfrequency of unscheduled repairs that suggest that the protectiveness of the remedy may be compromisedin the future.

There are no early indicators of potential problems with the remedy. The treatment system is welldesigned and constructed, with proper instrumentation, and appropriate for the groundwatercontaminants (please see below for optimization opportunities). Current maintenance activities do notsuggest apy trend in deterioration of the treatment system. The premature replacement of the GAC dueto mineral deposit fouling was the only unexpected change in O&M cost. However, proper preventativeprocedures are in place to periodically clean the GAC of deposits and extend its life, and should notresult in unexpected changes in the future.

030945 Final EATS J-Yr Rvw Rpt App B.doc

D. Opportunities for Optimization

Describe possible opportunities for optimization in monitoring tasks or the operation of the remedy.

Due to the low level of extracted contamjinants, the opportunity exists to select more effective andeconomical remedies (i.e. natural attenuation) and/or to optimize the treatment system operation.Monitoring tasks have already been reduced to yearly events.

030945 Final EATS 5-YrRvw Rpt AppB.doc

EATS (OU 5) Inspection Team Roster

Mike Klosky Foster Wheeler EnvironmentalBill Ogle Foster Wheeler EnvironmentalDuane Harrison Foster Wheeler Environmental

030945 Final EATS 5-Yr Rvw Rpi App B.doc

APPENDIX C

OPERABLE UNIT 5 PHOTOGRAPHS



030945 Final EATS 5-YrRvw Rpt.doc

*•***> Ii-csil Bag l:->tev

EATS Process Equipment Looking North

V>

EATS Process Equipment Looking East

I:\MOFFETT,Site 26 EATS'J-Year Review\Final\Appendices\030945 Final EATS 5-Yr Rvw Rpl App C doc Page

'WI

* Ml, .$>=

•it

I

••5

':t

EATS Bag Filters F-107A, B, C, & D

EATS Flow Transmitter

I :VMOFFFTT',Site 26 EATSY5-Year Review'.FinarAppendices\030945 Final EA [5 5-YrRvw Rpt App C.doc Page 2

EATS Liquid-Phase Granular ActivatedCarbon Units V-108 & V-109

\ 'MOFFETRSite 26 EATS\5-Year Review\FmaI\Appendices\030945 Final EATS 5-Yr Rvw Rpl App C.docPage 3

Looking North Looking West

<f

Looking East

Kly

4"Looking East

EATS Typical Wellheads

I MOFFETT'Site 26 EATS\5-Year Re\iew\FinarAppendices\030945 Final EATS 5-Yr Rvw Rpl App C doc Page 4

DEPARTMENT OF THE NAVYBASE REALIGNMENT AND CLOSURE

PROGRAM MANAGEMENT OFFICE WEST1230 COLUMBIA STREET, SUITE 1100

SAN DIEGO, CA 92101-8571

5090

SerBPMOW.mep/041217Feb2005

Ms. Alana Lee (3 copies; 3 CDs)U.S. Environmental Protection AgencyRegion IX75 Hawthorne Street, SFD-73San Francisco, CA 94105

Ms. Adriana Constantinescu (1 copy and 1 CD)Regional Water Quality Control BoardSan Francisco Bay Region1515 Clay Street, Suite 1400Oakland, CA 94612

Dear Ms. Lee and Ms. Constantinescu:

I am pleased to submit to you the Final East-Side Aquifer Treatment System(Operable Unit 5) Five-Year Review Report for the Period January 1999 to December2002, dated February 2005, the former Naval Air Station (NAS) Moffett Field, MoffettField, California. Mr. Richard Weissenborn, the Lead Remedial Project Manager andActing BRAC Environmental Coordinator, has reviewed this report.

If you have questions or comments, please contact Mr. Weissenborn at (619) 532-0952.

Sincerely,

ANN KLIMEKActing Base Closure ManagerBy direction of the Director

Enclosure: 1. Final East-Side Aquifer Treatment System (Operable Unit 5) Five-YearReview Report for the Period January 1999 to December 2002

Copy to: (w/encl)

Mr. Don Chuck (3 copies + 3 CDs)NASA M/S 218-1Ames Research CenterMoffett Field, CA 94035

Ms. Elizabeth Allen (+CD)TechLaw, Inc.90 New Montgomery Street, Suite 1010San Francisco, CA 94105

Mr. Kevin Woodhouse (CD only)City of Mountain View500 Castro StreetMountain View, CA 94087

Ms. L. Maile Smith (2 copies + 2 CDs)Weiss Associates350 East Middlefield RoadMountain View, CA 94043

Mr.Chuck Muir679 Emily DriveMountain View, CA 94043

Ms. Libby Lucas174 Yerba Santa Ave.Los Altos, CA 94022

Mr. Ty Johnson (CD only)727 J Orion ParkMountain View, CA 94043

Mr. Ken Naylor2098 Louise LaneLos Altos, CA 94024

Mr. Paul Lesti (+CD)1000 Elwell Court #203Palo Alto, CA 94303

5090SerBPMOW.mep/041217Feb2005

Ms. Shelly Clubb (+CD)NASA M/S 218-1Ames Research CenterMoffett Field, CA 94035

Mr. Bob Moss (CD only)BPAF4010 OrmePalo Alto, CA 94306

Mr. Tom Mohr (+CD)Santa Clara Valley Water District5750 Almaden Expressway, MS BHA-2San Jose, CA 95118

Mr. Peter Strauss (CD only)P.M. Strauss & Associates317RutledgeStreetSan Francisco, CA 94110

Mr. Ed Schlosser (CD only)304 Pacific DriveMountain View, CA 94043

Ms. Lily Toton698 Emerson StreetPalo Alto, CA 94301

Dr. James McClure (+CD)4957 Northdale DriveFremont, CA 94536

Mr. Justin ScheckMountain View Voice655 West EvelynMountain View, CA 95112

Mr. William Garbett683 Faye Park AvenueSan Jose, CA95136

Mr. Lenny Siegel (Executive Summary)269 Loreto StreetMountain View, CA 94041

Mr. Stuart McGee (Exec. Summary + CD)Dept. of Public Safety, Fire, & SpecialOperations700 All America WaySunnyvale, CA 94088-3707

Mr. William James (Executive Summary)Van Pelt & Yi LLP10050 N. Foothill Blvd., Suite 200Cupertino, CA 95014

Mr. Dan Wallace (Executive Summary)532Tyrella#18Mountain View, CA 94043

Mr. Kran Kilpatrick (Executive Summary)NASA M/S 218-1Ames Research CenterMoffett Field, CA 94035

5090SerBPMOW.mep/041217Feb2005

Mr. Steve Sprugasci (Executive Summary)680 North 16th StreetSan Jose, CA 95112-3024

Ms. Jane Turnbull (Executive Summary)64 Los Altos SquareLos Altos, CA 94022

Mr. Joseph Chou (Executive Summary)P.O. Box 5602San Mateo, CA 94402

Mr. R. Eckert (Executive Summary)1623 Ben Roe DriveLos Altos, CA 94024

UNITED STATES ENVIRONMENTAL PROTECTION AGENCYREGION IX

75 Hawthorne StreetSan Francisco, CA 94105

September 30, 2005

Mr. Richard WeissenbornBRAC Environmental CoordinatorDepartment of the NavyBRAC Program Management Office West1455 Frazee Road, Suite 900San Diego, CA 92 108-43 10

RE: EPA Concurrence - Final East-side Aquifer Treatment System (Operable Unit 5)First Five- Year Review Report for the Period January 1999 to December 2002Former Naval Air Station Moffett Field, Moffett Field, California, dated February 2005

Dear Mr. Weissenborn:

The U.S. Environmental Protection Agency (EPA) has reviewed the Final East-sideAquifer Treatment System (Operable Unit 5) Five-Year Review Report for the Period January1999 to December 2002, Former Naval Air Station Moffett Field, Moffett Field, California,dated February 2005. EPA concurs with the Operable Unit (OU) 5 Five- Year Review Report'sfindings and protectiveness statement.

EPA would like to clarify, however, that certain institutional controls required by the1996 OU 5 Record of Decision (ROD) have yet to be implemented. Specifically, the RODrequires incorporation of access restrictions on the domestic use of the OU 5 groundwater intothe appropriate land use documents. As we have discussed, NASA's 1994 Comprehensive UsePlan currently contains language that provides short-term protection from exposure tocontamination through restrictions on access and development in the OU 5 area for safetyreasons related to munitions storage and runway/air operations. To ensure long term-protectionand appropriate notice to future landowners, access restrictions should be added to the Plan thatspecifically restrict access to groundwater at OU 5 as set forth in the ROD. We understand andappreciate that the Navy has requested that NASA incorporate such land use controls languageinto the Plan in a November 8, 2004 letter, and hope to see that language adopted in the nearfuture.

We appreciate the Navy's efforts in working closely with EPA to resolve our remainingissues on this Five- Year Review Report.

Sincerely,

Kathleen JohnsonFederal Facilities and Site Cleanup Branch ChiefSuperfund Division

cc: Sandy Olliges, NASA

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