final first five-year review of the soil cleanup of irp ... · final first five-year review of the...

SFUND RECORDS CTR

2165779

FINAL

First Five-Year Review of the Record of Decision for

Soil Cleanup of IRP Sites 1, 2, and 3 Air Force Plant 44, Tucson, Arizona

Operable Unit 03 of the Tucson International Airport Area Superfund Site

Prepared by:

Prepared for:

October 2004

EARTH TECH, INC. 5575 DTC Parkway, Suite 200 Englewood, Colorado 80111

UNITED STATES AIR FORCE AERONAUTICAL SYSTEMS CENTER

Acquisition Environmental, Safety and Health Division Engineering Directorate

Wright-Patterson AFB, Ohio 45433

Rdytheon RAYTHEON SYSTEMS COMPANY

Environmental Health and Safety 1151 E. Hermans Road, Bldg. 826

Tucson, Arizona 85706

5 5 7 5 D T C P a r k w a y , S u i t e 2 0 0 , E n g l e w o o d , C o l o r a d o 8 0 1 1 1 - 3 0 1 6

October 14, 2004

Mr. George Warner Aeronautical Systems Center/EMR Building 8 1801 Tenth Street, Suite 2 Wright-Patterson AFB, OH 45433-7626

Subject: Final 5-Year ROD Reviews for Sites 1, 2 and 3 and Sites 4,5, and 6

_ . _ '' T e l e p h o n e

Dear George: 3 0 3 . 6 9 4 . 6 6 6 0

Enclosed please find two copies, with the appropriate signature, of the Final 5-Year ROD Reviews for Sites 1, 2, and 3 and for Sites 4, 5, and 6 at Air Force Plant 44, in Tucson, AZ. Facsimile

• Matt Jefferson, USA REPA, Region 9 - 2 copies 303.694.4410 • Bill Ellett, ADEQ - 2 copies • George Warner, ASC RPM - 2 copies • Jean Roberts, Raytheon - 2 copies • TCE Superfund Library - 1 copy

Please do not hesitate to call me at 303.804.2354 or Bill DiGuiseppi at 303.804.2356 if you have questions or need additional copies or information.

Sasha G. Woodard, E.I. Project Engineer

cc: 26636.01 Earth Tech File

E A R T H ^ ^ 1 T E C H

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A Tyco Infrastructure Services Company

^c^^ 2 0 2004

Raytheon

in reply referto: 8200/TJA'9140 March 15,2004

Raytheon Company

POBox 11337, Bldg. 826 Tucson, AZ 85734-1337

520.794.9450

Mr. George Warner ASC/EMR 1801 Tenth St, Bldg. 8 Ste. 2 Wright-Patterson AFB, OH 45433-7626

Mr. Matthew Jefferson US EPA, Region IX 75 Hawthorne St D-7-1 San Francisco, CA 94105-3901

Mr. William Ellett ADEQ Project Manager, Superfund Progrann 400 West Congress, Suite 433 Tucson, AZ 85701

ADWR Water Quality Section 500 N. Third St. Phoenix, AZ 85004-3903

re: Summary of Reclamation Well Field and Soil Remediation Operations, July through December 2003 U.S. Air Force Plant 44 (AFP 44), Tucson, Arizona

Dear Agency Representatives:

Enclosed for your review is the annual report titled "Summary of Reclamation Well Field and Soil Remediation Operations, July through December, 2003, U.S. Air Force Plant 44, Tucson, Arizona".

This report contains operations data forthe Installation Restoration Program (IRP) groundwater and soils remediation activities at AFP 44, located in the southern portion of the Tucson International Airport Area Superfund National Priorities List site. The report is prepared by Raytheon Company, uncler direction ofthe United States Air Force Aeronautical Systems Center, Installation Restoration Program

If you have any questions regarding any of the information contained within this report, please contact me at 520-794-9450 or e-mail me at [email protected] .

Sincerely,

RAYTHEON COMPANY

Timothy J. Allen Hydrogeologist Environmental Restoration Program

mailto:[email protected]

Distribution:

Biggs, Jeff Cronin, K. De la Cruz DiGuiseppi, W. Gomez, I. Graham, D. Grimaldi, R. Herrera, M. Huckelberry, C. Kaftira, C. Katz, L. Keene, J. D. Kusel R. Marra Pearthree, M. Rogers, S.

Raytheon:

Bramhall, D Hannifan, R. Luhrs, R. Maxwell, T. Padilla, R. Roberts, I.J. Samorano, D. Steiner, G.D. Taylor, G. Tiemey, K. File 826

COT Water Tohono O'Odham Superfund Library Earth Tech UCAB USGS Pima County DEQ TCE Subcommittee Pima County Mgr. ADEQ Montgomery & Assoc. City of Tucson ADWR COT Water COT Water San Xavier District

FINAL

First Five-Year Review of the Record of Decision for

Soil Cleanup of IRP Sites 1,2, and 3 Air Force Plant 44, Tucson, Arizona

Operable Unit 03 ofthe Tucson Intemational Airport Area Superfund Site

2* £ ^ oj DATE

Lieutenant General, USAF Vice Commander

I I

Final First Five-Year Review of the Record of Decision for Soil Cleanup of

IRP Sites I. 2. and 3 Air Force Plant 44, Tucson. .Arizona

Operable Unit 03 ofthe Tucson International A irport A rea Superfund Site

TABLE OF CONTENTS

Page No.

LIST OF TABLES iii

LIST OF FIGURES iii

LIST OF ATTACHMENTS iii

LIST OF ACRONYMS v

EXECUTIVE SUMMARY ES-1

FIVE-YEAR REVIEW SUMMARY FORM F-l

1.0 INTRODUCTION 1-1 1.1 PURPOSE OF REVIEW l-I 1.2 AUTHORITIES .: 1-1 1.3 LEAD.AGENT/CONTRACTOR SUPPORTING LEAD AGENCY 1 -1 1.4 REVIEW NUMBER 1-2 1.5 TRIGGER ACTION/DATE.... 1-Z 1.6 NUMBER, DESCRIPTION AND STATUS OF OTHER IRP SITES AT AFP 44.. 1 -2

2.0 SITE CHRONOLOGY 2-1

3.0 BACKGROUND 3-1 3.1 GENERAL SITE DESCRIPTION 3-1 3.2 FORMER, CURRENT AND FUTURE LAND USE 3-2 3.3 HISTORY OF WASTE DISPOSAL/CONTAMINATION 3-2 3.4 INITIAL RESPONSE : 3-3

4.0 REMEDIAL ACTIONS 4-1 4.1 REGULATORY ACTIONS 4-1 4.2 REMEDIAL ACTION OBJECTIVES 4-1 4.3 REMEDY DESCRIPTION 4-1

5.0 PROGRESS SINCE THE LAST FIVE-YEAR REVIEW 5-1

6.0 FIVE-YEAR REVIEW PROCESS 6-1 6.1 ADMINISTRATIVE COMPONENTS 6-1 6.2 COMMUNITY INVOLVEMENT 6-1 6.3 DOCUMENT REVIEW 6-1 6.4 DATA REVIEW 6-2 6.5 SITE INSPECTION 6-2 6.6 INTERVIEWS 6-3

7.0 TECHNICAL ASSESSMENT 7-1

8.0 ISSUES ! 8-1

9.0 RECOMMENDATIONS AND FOLLOW-UP ACTIONS 9-1

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i

Final First Five- Year Review ofthe Record of Decision for Soil Cleanup of

IRP Sites 1,2. and 3 .Air Force Plant 44. Tucson, Arizona

Operable Unit 03 ofthe Tucson International Airport Area Superfund Site

TABLE OF CONTENTS (CONTINUED) Page No.

10.0 PROTECTIVENESS STATEMENT 10-1

11.0 NEXT REVIEW... 11-1

12.0 REFERENCES 12-1

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IRP Sites I. 2, and 3 Air Force Plant 44, Tucson, Arizona

Operable Unit 03 ofthe Tucson International Airport Area Supeifund Site

LIST OF TABLES

Table Title

2-1 General Chronology of Soil Remediation, AFP 44 Sites 1, 2, and 3 4-1 IRP Sites 1, 2, and 3 Removal Action Status 7-1 System Duration and Costs for IRP Sites 1, 2, and 3 7-2 Preliminary Trigger Levels for TCE and Potential Maximum TCE Groundwater

Levels for Sites 1, 2, and 3 7-3 Original and Revised Chemical-Specific ARARs and TBCs 8-1 Issues Raised in Five-Year Review of AFP 44, Sites 1, 2, and 3 9-1 Recommendations and Follow-Up Actions at AFP 44, Sites 1, 2, and 3

LIST OF FIGURES

Figure Title

1 Soil Restoration Locations, Air Force Plant 44

LIST OF ATTACHMENTS

Attachment Title

1 IRP Site 1 Detailed Site Review 2 IRP Site 2 Detailed Site Review 3 IRP Site 3 Detailed Site Review 4 Responsiveness Summary - IRP Sites 1, 2, and 3

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IRP Sites I, 2. and 3 .Air Force Plant 44. Tucson. Arizona

Operable Unit 03 of the Tucson International Airport Area Superfund Site

LIST OF ACRONYMS

ADEQ ADHS AFP 44 AFRIMS ARAR bgs CERCLA CFR DCE DEUR EE/CA ESD FACO FS GAC GSA HBGL IRIS IRP MCL mg/kg NCP RAO RI ROD RPM SARA SRLs SVE TCA TCE TIAA TPH UCAB USEPA VOC

Arizona Department of Environmental Quality Arizona Department of Health Services Air Force Plant 44 Air Force Restoration Information Management System applicable or relevant and appropriate requirement below ground surface Comprehensive Environmental Response, Compensation, and Liability Act Code of Federal Regulations dichloroethylene Declaration of Environmental Use Restriction Engineering Evaluation/Cost Analysis Explanation of Significant Difference Final Assembly and Checkout Feasibility Study granular-activated carbon General Service Agency human health-based guidance level Integrated Risk Infomiation System Installation Restoration Program maximum contaminant level milligrams per kilogram National Oil and Hazardous Substances Pollution Contingency Plan Remedial Action Objective Remedial Investigation Record of Decision Remedial Project Manager Superfimd Amendments and Reauthorization Act soil remediation levels soil vapor extraction 1,1,1-trichloroethane trichloroethylene Tucson Intemational Airport Area total petroleum hydrocarbon Unified Community Advisory Board United States Environmental Protection Agency volatile organic compound micrograms per liter

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iv October 2004


IRP Sites I, 2. and 3 Air Force Plant 44, Tucson, Arizona


EXECUTIVE SUMMARY

This statutory five-year review for Air Force Plant 44 (AFP 44) Installation Restoration Program

(IRP) Sites 1, 2, and 3 (Air Force Restoration Infomiation Management System [AFRIMS] Sites

DPOOl, DP002, DP003, respectively) is required because post-Superfund Amendments and

Reauthorization Act (SARA) remediation left hazardous substances in the soils above levels that

allow for unlimited use and unrestricted exposure. The purpose of this review is to evaluate the

implementation and perfomiance of the remedy, soil vapor extraction (SVE), to determine

whether it is or will be protective of human health and the environment. The trigger date for the

first five-year review for IRP Sites 1, 2, and 3 is the date of initiation of removal action.

Activities to implement the remedy at IRP Sites 1, 2, and 3 were initiated by the United States

Air Force on 3 January 1996. With this being the trigger date for the five-year review process

for these sites, the first five-year review was scheduled to be conducted on 3 January 2001.

However, the first five-year review was initiated in May 2002 due to technical delays vvith

implementation of Remedial Process Optimization recommendations such as eliminating

potential risk from the SVE systems emissions.

AFP 44 currently operates one SVE systeni for soil remediation at IRP Site 3. IRP Site 2, where

a SVE system was fomierly operated for soil remediation, is awaiting approval of a removal

action completion report. At IRP Site 1, remediation is complete for soil contaminants, and the

removal action completion report has been finalized and approved by the United States

Environmental Protection Agency (USEPA) and the Arizona Department of Environmental

Quality (ADEQ). IRP Sites 1 and 2 are restricted to nonresidential uses because of the total

petroleum hydrocarbon (TPH)-contaminated soil that was left in place.

The selected soil remedy for IRP Sites 1, 2, and 3 is protective of human health and the

environment such that the residual volatile organic compound (VOC) contamination will not

cause or contribute to an exceedance ofthe maximum contaminant levels (MCL) in groundwater.

Residual TPH contamination is either below ADEQ soil remediation levels (SRLs) for non

residential usage or is below the levels that would threaten human health, the environment, or

groundwater quality based on calculations made within the risk assessnient. Residual metals

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ES-1


IRP Sites j . 2 , and 3 Air Force Plant 44, Tucson, Arizona

Operable Unit 03 ofthe Tucson International .Airport Area Superfiind Site

contamination is below ADEQ residential SRLs. Current monitoring data indicate that the

remedy is functioning as required to achieve soil cleanup goals. Long-term protection will be

verified by obtaining additional groundwater monitoring samples as part of the regional

groundwater cleanup.

This first five-year review indicated that the remedy was constmcted in accordance with the

requirements of the Record of Decision (ROD) for IRP Sites 1, 2, and 3 and is functioning as

designed. An Explanation of Significant Difference (ESD) was issued to change the soil cleanup

level for TPH at IRP Sites 1, 2, and 3 to be consistent with current Arizona soil remediation

levels for non-residential land use. Immediate threats have been addressed, and the remedy for

IRP Sites 1, 2, and 3 is expected to be or is protective of human health and the environment

under non-residential land use scenarios.

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ES-2


IRP Sites I. 2, and 3 Air Force Plant 44. Tucson. Arizona

Operable Unit 03 ofthe Tucson International A irport A rea Superfund Site

Five-Year Review Summary Form

SITE IDENTIFICATION

Site Name (from WasteLAN): TUCSON INTERNATIONAL AIRPORT AREA~OU ID 03, Air Force Plant #44, Soil Cleanup Sites 1, 2, and 3. EPA ID (from WasteLAN): AZD980737530

Region: 9 State: AZ City/County: Tucson/Plma

SITE STATUS

NPL Status: | 3 Final D Deleted D Other (specify)

Remediation Status (choose all that apply): Q Under Construction ^ Operating ^ Complete Site 3: operating; Sites 1 and 2: complete (Site 2 await ing approval) Multiple OUs? D Y e s ^ No Construction Completion Date: Site 1: July 1996; Site 2: August

1996; Site 3: October 1996 Has site been put into reuse? Q Yes ^ No

REVIEW STATUS

Lead Agency: D EPA • State D Tribe M Other (United States Air Force)

Author Name: Barbara M. Young

Author Title: Sr. Environmental Scientist Author Aff i l iat ion: Earth Tech, Inc.

Review Period: 5 / 1 / 2002 to 3 / 1 9 / 2 0 0 3

Date(s) of Site Inspection: 7 / 1 6 / 2 0 0 2 and 3 / 1 9 / 2 0 0 3

Type of Review: IE] Post-SARA n Pre-SARA Q NPL-Removal only n Non-NPL Remedial Action Site D NPL State/Tribe-lead I I Regional Discretion

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

Triggering Act ion: 1^ Actual RA On-site Constmction at OU # OSQ Actual RA Start at 0U# I I Constmction Completion Q Previous Five-Year Review Report D Other

Triggering Act ion Date (from IVasfeMA/): Activities to implement the remedy at IRP Sites 1, 2, and 3 were initiated by the Air Force on 3 January 1996. Due Date (five years after tr iggering action date: 3 January 2001

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IRP Sites 1. 2. and 3 Air Force Plant 44. Tucson. .Arizona

Operable Unit 03 ofthe Tucson International A irport Area Superfund Site

Five-Year Review Summary Form

(Continued)

Issues:

IRP Si te i : None. Regulatory closure is complete.

IRP Site 2: Total petroleum hydrocarbons (TPH) are found in concentrations above the ADEQ soil remediation levels (SRLs) for non-residential land use specified as the cleanup level in the May 2000 Explanation of Significant Difference (ESD). Due to depth to groundwater (e.g., 150 feet), data showing no impacts to groundwater from the TPH, and the lack of complete exposure pathways, the Air Force asked ADEQ to evaluate potential risk from TPH at Site 2. In March 2003, ADEQ found that residual risk from TPH does not pose an unacceptable risk to human health for residential or non-residential uses; thus the TPH will be left in place.

IRP Site 3: Modeling of the post-primary granular activated carbon (GAC) air emissions from the active SVE remediation system suggested the potential for unacceptable risks to human health for on-site workers and off-site receptors from after-treatment off-gas. The only time that risk could occur is when there is breakthrough of the primary GAC units, at which time the Air Force shuts down the system and replaces the carbon. To alleviate the potential for unacceptable risk from volatile organic compounds (VOCs) in the future, the Air Force added a secondary carbon unit to the system in 2003, following the primary GAC treatment.

Recommendations and Follow-up Act ions:

IRP Site 2: ADEQ risk assessors concluded that the TPH in soil poses no unacceptable risks regardless of use. Therefore, the Air Force will leave the TPH-contaminated soils in place at IRP Site 2. The Air Force requested an exception for using a risk-based standard for TPH (rather than the ADEQ non-residential SRLs) in the IRP Site 2 closure documents submitted to ADEQ in September 2003.

Protectiveness Statement(s):

All soil (unsaturated zone) contamination at IRP Sites 1, 2, and 3 is either currently being addressed or has been addressed. The remedy for IRP Sites 1, 2, and 3 is expected to be or is protective of human health and the environment. Exposure pathways that could result in unacceptable risk are being controlled.

Long-term Protectiveness:

Current monitoring data indicate that the remedy for IRP Sites 1, 2, and 3 is functioning as required to address contamination in the soil (unsaturated zone), such that the residual VOC contamination will not cause or contribute to an exceedance of the maximum contaminant levels (MCLs) in groundwater, residual TPH contamination is below ADEQ non-residential SRLs or does not threaten human health or the environment or groundwater quality (at IRP Site 2), and residual metals contamination is below ADEQ residential SRLs.

Other Comments:

VOC contaminants at AFP 44 are trapped in continuous strata of reddish brown sandy clay and clay that occurs between about 80 and 130 feet deep that is locally referred to as the Upper Clay Unit. This horizon is beneath IRP Sites 1, 2, and 3 and is in contact with groundwater. This source area was not addressed in the Record of Decision (ROD) for IRP Sites 1, 2, and 3 and is not addressed in this five-year review. However, the Air Force is actively addressing this source area as part of IRP Site 17 -Regional Groundwater (Air Force Restoration Information Management System [AFRIMS] Site 12) under a 1986 Remedial Action Plan. Recent and ongoing pilot testing of innovative remedial technologies show that insitu oxidation using potassium permanganate may be an effective technology for destruction of the VOCs in the clay unit.

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F-2

Final First Five-Year Review ofthe Record of Decision for Soil Cleanup qf

IRP Sites I, 2, and 3 .Air Force Plant 44,. Tucson, Arizona


1.0 INTRODUCTION

1.1 PURPOSE OF REVIEW

The purpose ofthis five-year review is to evaluate the implementation and performance ofthe

soil vapor extraction (SVE) remedy for soils at Installation Restoration Program (IRP) Sites 1, 2,

and 3 (Air Force Restoration Information Management System [AFRIMS] Sites DPOOl, DP002,

DP003, respectively) at Air Force Plant 44 (AFP 44) and to determine whether the remedy is

protective of human health and the environment. The methods, findings, and conclusions are

documented in this five-year review report. In addition, this report identifies issues found during

the review and makes recommendations to address them.

1.2 AUTHORITIES

The United States Air Force (USAF) conducted this five-year review from May 2002 through

May 2003 pursuant to Comprehensive Environmental Response, Compensation, and Liability

Act (CERCLA) §121 and the National Oil and Hazardous Substances Pollution Contingency

Plan (NCP). CERCLA §121 states:

"If the President selects a remedial action that results in any hazardous substances, pollutants, or contaminants remaining at the site, the President shall review such remedial action no less often than each five years after the initiation of such remedial action to assure that human health and the environment are being protected by the remedial action being implemented. "

Pursuant to the NCP, 40 Code of Federal Regulations (CFR) §300.430(f)(4)(ii), a statutory five-

year review is required for remedies at IRP Sites 1, 2, and 3 at AFP 44 because the remedial

action will leave hazardous substances, pollutants, or contaminants onsite above levels that allow

for unlimited use and unrestricted exposure.

1.3 LEAD AGENT/CONTRACTOR SUPPORTING LEAD AGENCY

The lead agency is the USAF, Aeronautical Systems Center, Acquisition, Environmental, Safety

and Health Division, Wright-Patterson Air Force Base, Ohio. Earth Tech, Inc., Englewood,

Colorado, conducted this review for the lead agency.

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Final

f

First Five-Year Review ofthe Record of Decision for Soil Cleanup qf

IRP Sites I. 2, and 3: .Air Force Plant 44, Tucson. Arizona


1.4 REVIEW NUMBER

This is the first five-year review for IRP Sites 1, 2, and 3.

1.5 TRIGGER ACTION/DATE

The trigger date for this first five-year review is the start date of initiation ofthe remedial action.

Various activities to implement the remedy at IRP Sites 1, 2, and 3 (a non-time critical removal

action) began on 3 January 1996! Thus, the due date for the first five-year review was

3 January 2001 (five years from the trigger date).

1.6 NUMBER, DESCRIPTION AND STATUS OF OTHER IRP SITES AT AFP 44

Only IRP Sites 1, 2, and 3 are addressed by this Record of Decision (ROD) review. AFP 44 has

seven other IRP sites.

• IRP Site 4 (Fonner Unlined Surface Impoundments) (AFRIMS Site WP004) • IRP Site 5 (Former Sludge Drying Beds) (AFRIMS Site WP005) • IRP Site 6 (Unlined Drainage Channels) (AFRIMS Site SD006) • IRP Site 7 (North Final Assembly and Checkout [FACO] Fire Training Area) (AFRIMS

SiteFT007) • IRP Site 8 (South FACO Fire Training Area and Magnesium Bum Area) (AFRIMS

Site FT008) • IRP Site 9 (Explosive Detonation Pit) • IRP Site 15 (Potential Trench Site) (AFRIMS Site DP004)

IRP Sites 4, 5, and 6 are addressed in a separate ROD review (Earth Tech 2003b). IRP Sites 4,

5, and 6 have removal actions completed for metal contaminants in soil; SVE is operating at IRP

Site 5 for volatile organic compounds (VOCs). A five-year ROD review for IRP Sites 4, 5, and

6 has been issued concurrently with this five-year ROD review for IRP Sites 1, 2, and 3.

IRP Sites 7, 8, 9, and 15 have no restrictions on the potential use of soil and have no

requirements for monitoring because they pose no significant impact to human health and/or the

environment (Earth Tech 1994a, b, c, and d).

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Final First Five- Year Review ofthe Record of Decision for Soil Cleanup qf

IRP Sites I. 2. and 3 Air Force Plant 44, Tucson, .Arizona


There are two groundwater IRP sites at AFP 44. These are IRP Site 14 - Shallow Groundwater

Zone (AFRIMS Site OTO 13) and Site 17 - Regional Groundwater (AFRIMS Site OTO 12). The

non-time critical removal action at IRP Site 14 (pump and treat with dual-phase extraction) is

ongoing. Similarly, operation of the groundwater pump and treat systeni at IRP Site 17

continues.

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Final First Five-Year Revieiv ofthe Record of Decision for Soil Cleanup of

IRP Sites I. 2, and 3 Air Force Plant 44, Tucson. Arizona

Operable Unit 03 ofthe Tucson International .Airport Area Superfund Site

2.0 SITE CHRONOLOGY

Table 2-1 is a general chronology of events at IRP Sites 1, 2, and 3. For the detailed chronology

of soil remediation by site, refer to the detailed site descriptions in Attachments 1, 2, and 3.

Table 2-1: General Chronology of Soil Remediation, IRP Sites 1, 2, and 3

Event

AFP 44 listed on National Priorities List.

AFP 44 groundwater remediation system activated.

Stage 1 remedial investigation (RJ), risk assessment and feasibility study (FS) initiated for 10 historic sites, including IRP Sites 1, 2, and 3. Fieldwork associated with Rl conducted

Interim Rl report submitted to regulators.

SVE treatability study.

Baseline human health risk assessment completed for contaminated soil.

Final Risk Assessment Report approved.

Supplement 1 to interim Rl report for 10 historic sites, including IRP Sites 1, 2, and 3, submitted. SVE tested on specially constructed groundwater extraction wells at IRP Site 3.

FS submitted for approval.

Supplement 2 to interim RI report for 10 historic sites, including IRP Sites 1, 2, and 3, submitted. SVE tested on specially constiiicted groundwater extraction wells at IRP Site 2. Proposed plan. Engineering Evaluation/Cost Analyses (EE/CAs) and removal work plans for IRP Sites 1, 2, and 3, submitted. ROD for IRP Sites 1, 2, and 3, signed by the USAF. IRP Site 1 - SVE system activated in July 1996. SVE system shut down in August 1997. Four quarters of monitoring followed. March 1999, elevated VOCs and total petroleum hydrocarbon (TPH) detected in soil and soil vapor samples. SVE system connected to vapor monitoring well and operated six months. January 2000, IRP Site 1 reaches ROD cleanup standards and draft remedial action completion report submitted. IRP Site 2 - SVE systems activated in August 1996. September 1998, back-up granular activated carbon (GAC) unit added to allow operation while the resin units being repaired. January 1999, crossover piping installed to interconnect all ofthe compounds to GAC unit. SVE activities were discontinued in November 2000 and 4 quarters pf monitoring were performed. Final Site 2 Remedial Action Completion Report submitted.

IRP Site 3 - SVE system activated in October 1996. Three new wells added in May 1998. Six more wells drilled in January 2000. Four of these were connected to the system. Explanation of Significant Difference (ESD) issued to revise cleanup criteria for TPH in IRP Sites 1,2, and 3 ROD.

IRP Site 1 completion report approved.

Date

1983

1987

1989

1991 and early 1992

July 1992

January 1993

August 1993

October 1993

January 1994

August 1994-March 1995

January 1995

1996

April 1995-July 1996 September 1995

19 May 1998 July 1996-Jan 2000

January 2000

1996-2003

September 2003

1996 to present

May 2000

September 2000

L:\mii-k\26616\»'oi-k':Pi-oJnel\5-Yei ]-l\lttelMles Clk-itl's Commenls lll-l2-ll4^Finul I-'.

2-\ I Five-Yr ROD CLRevieu2.Jttc October 2004


IRP Sites I, 2, and 3 .Air Force Plant 44, Tucson. Arizona


3.0 BACKGROUND

3.1 GENERAL SITE DESCRIPTION

AFP 44 consists of approximately 1,380 acres and 123 buildings located in Pima County,

Arizona. It is located 15 miles south of downtown Tucson, Arizona. Immediately east and

contiguous to the plant lies the Tucson Intemational Airport. The Nogales railroad spur, Nogales

Highway (U.S. Route 89), private property, and the San Xavier Tohono-O'odham Indian

Reservation lie west of the plant. Vacant land and light comniercial property lie to the south.

The elevation at AFP 44 is approximately 2,600 feet above mean sea level.

AFP 44 is located in the Tucson Basin of the Santa Cmz River drainage system of the Sonoran

Desert. The Tucson Basin is a broad, northwest trending alluvial valley encompassing about 750

square miles in Pima County. The basin is located in the alluvial basin hydrogeologic province

and the basin and range geologic province. These provinces are characterized by north to

northwest trending fault-block mountains separated by either desert plains or broad, gently

sloping alluvial basins and alluvial niaterial consisting of clays, silts, sands, and gravels that

eroded from the mountains and filled the basins. It is likely that the bedrock geology underlying

AFP 44 at great depth is crystalline rock consisting of granite, granite-gneiss, schist, andesite,

basalt, and limestone. Surface geology consists of alluvial sediment interbedded locally with

volcanic flows, agglomerates, and tuffaceous sediments. The alluvial sediments underlying AFP

44 have been characterized as belonging to four groups: surficial deposits. Fort Lowell

Formation, Tinaja beds, and Pantano Formation.

The hydrology in the vicinity of AFP 44 is characterized by a regional aquifer system composed

of an upper and a lower zone separated by an extensive clay confining layer. Regional

groundwater flow beneath the plant is generally to the northwest with a hydraulic gradient of

approximately 15 feet per mile. The top ofthe lower aquifer zone is approximately 300 feet

below ground surface (bgs). The Santa Cmz River is located 1.5 miles from the westem

boundary of AFP 44 and flows directly north. Because of the small quantity and irregularity of

rainfall in the Sonoran Desert, the river and its tributaries have erratic natural flow.

L:Woi-k\266}6W<nk\Pi-oJiict'5-YearRevie.v\Finol:l-2-3Mneln.les Client's Commenls lll-l2-ll4\Flnol 1-2-1 Five-Yr ROD CLRevie..2.Joe OctObCr 2004

3-1


IRP Sites 1,2, and'3 Air Force Plant 44, Tucson, .Arizona


IRP Sites 1 and 2 are located in the southeast quadrant of AFP 44. IRP Site 1 encompasses about

32 acres and lies near Buildings 853, 854, and 855. IRP Site 2 encompasses about 6.5 acres and

lies near Building 864. IRP Site 3 encompasses 78 acres and is located in the north-central

secfion ofthe plant near Buildings 826, 827A, 827C, 815A and 828.

3.2 FORMER, CURRENT AND FUTURE LAND USE

Prior to 1951, the area where AFP 44 is located was vacant land except for a ranch that was

located near the present IRP Site 1. Since 1951, when AFP 44 was constmcted, the property has

been used as an industrial facility. Industrial use ofthe property will continue for the foreseeable

future.

3.3 HISTORY OF WASTE DISPOSAL/CONTAMINATION

Manufacturing activities at AFP 44 began in 1951. Past disposal practices included discharge of

wastewater from plating operations to an unlined ditch; discharge of wastewater to unlined

surface impoundments; and disposal of general industrial waste such as spent solvents, coolants,

lubricants, paint residue, sludge, and diluted and concentrated acids and alkalines into unlined

pits and trenches.

Unlined trenches located in the area of IRP Site 1 were used for general waste disposal from

1952 to 1955. Garbage, machining coolants and lubricants, trichloroethylene (TCE), methylene

chloride, spent solvents (not otherwise specified), and paint sludge and thinners are known to

have been disposed of at this site. Former septic tank leachfields are also located at the site.

From 1955 to the late 1960s/early 1970s, IRP Site 2 received solids and liquid waste consisting

of flammable solvents, spent 1,1,1-trichloroethane (TCA), TCE, methylene chloride, machine

coolants and lubricants, paint sludge and thinners, and other unidentified solvents. From 1955 to

1966, about 7,000 gallons of flammable liquids were disposed of each week in six to eight

disposal trenches on the site. From 1955 to 1963, flammable liquids in the trenches were bumed

four times per week while solids were bumed nightly. Although buming stopped in 1963,

disposal at the site continued until the late 1960s or early 1970s.

L:-.uiu-k\26616',iyitik\Pr<,<lttel\5-Year Revieiv\Finttl\l-2-J\lnelti,lesClknl's Comments III-12-114'Fin,tn-2-l Five-Yr ROD CLRevie.v2.,lik Octobcr 2004

3-2


IRP Sites I. 2. and 3 Air Force Plant 44, Tucson, Arizona


From 1966 to 1977, unlined pits at IRP Site 3 were used for solvent disposal. In addifion, the

southern half of the site was used for burial of containerized liquid waste.

The first indications of groundwater contamination in areas near AFP 44 appeared in the early

1950s when elevated levels of chromium were detected in a municipal supply well adjacent to

the plant, and residents around the Tucson Intemational Airport complained of foul-smelling

water from private supply wells. In 1976, a water supply well was closed at AFP 44 by the State

because of high levels of chromium. In early 1981, the United States Environmental Protection

Agency (USEPA) and Arizona Department of Health Services (ADHS) identified VOCs and

elevated levels of nietals in the upper zone of the regional aquifer underlying areas around the

Tucson International Airport. Consequently, the City of Tucson began closing all municipal

wells that exceeded the State action level for all regulated contaminants and notified private well

users of potential risks. On behalf of the US Air Force, Hughes Aircraft Company, the operator

of AFP 44 initiated extensive groundwater investigations to detemiine if contamination existed

under the plant and, ifso, the nature and extent of contamination. These investigations showed

contamination in the form of metals and chlorinated solvents. In 1983, the Tucson Intemational

Airport Area (TIAA), including AFP 44, was placed on the National Priorities List (NPL).

3.4 INITIAL RESPONSE

In 1985, the Air Force conducted an IRP Phase I records search for AFP 44. Also in 1985, the

USAF developed a plan to conduct a Stage I remedial investigation (Rl) of 10 historical sites,

including IRP Sites 1, 2, and 3. Fieldwork associated with the Stage I RI was conducted in 1991

and early 1992. An interim RI report was submitted to the Arizona Department of

Environmental Quality (ADEQ) and the USEPA in July 1992 (Earth Tech 1992). After

additional fieldwork was conducted in 1993 and 1995, supplements to the interim RI report were

generated. These supplements were submitted to USEPA and ADEQ in 1994 and 1996

(EarthTech 1994e, 1996).

Based on the results of the interim RI, the USAF initiated a baseline human health risk

assessment; a treatability study for IRP Sites I, 2, and 3; and a feasibility study (FS). The risk

L-Wotk\266i6\noi-k\Pnuliiet\5-Yeiir Rcvie\v\Finol..l-2-.l',lncliiik-s Client's Comments 1(1-12-(l4\Fimil 1-2-1 Ftve-Yr ROD CLRevie\v2.,loe October 2004

3-3


IRP Sites I, 2. and i .Air Force Plant 44, Tucson, .Arizona


assessment was completed in 1993 (Earth Tech 1993). The FS was completed in January 1995.

It evaluated potential remedial altematives for the cleanup of contaminated soils (Earth Tech

1995a). The USAF submitted a work plan for a non-time critical removal action at IRP Sites I,

2, and 3 (Earth Tech 1995b), an Engineering Evaluation/Cost Analysis (EE/CA) (Earth Tech

1995c), and a Proposed Plan to USEPA and ADEQ in September 1995. Implementation ofthe

non-time critical removal action at IRP Sites 1, 2, and 3 began in January 1996, to eliminate

continuing sources of groundwater contamination and/or to address potential risks to human

health and the environment. The USAF signed the ROD for IRP Sites 1, 2, and 3 on

19 May 1998. The ROD selected the ongoing removal action, SVE, as the final, permanent

remedy for each site.

L:'ivoik\266.l6\»'ot-k'.Pt-o,liiet\>-YectrRevien-\Finol'l-2-l^lneliiLlesClkm's Comments III-l 2-ll4'Fittal 1-2-1 Five-Yr ROD CLRcvteir2.iloc OctObcF 2004

3-4

Final First Five-Year Review ofthe Record of Decision for Soil Cleanup of

IRP Sites 1, 2. and 3 Air Force Plant 44, Tucson, Arizona


4.0 REMEDIAL ACTIONS

SVE with resin adsorption units for VOC capture was selected as the final remedy for IRP Site 2.

SVE with GAC was selected as the final remedy for IRP Sites 1 and 3 and was later used at

Site 2 to optimize the remedy. Table 4-1 summarizes the stams ofeach site. Complete details on

each site are provided in Attachments 1, 2, and 3.

4.1 REGULATORY ACTIONS

EE/CA approved (30 Nov 1995) ROD for IRP Site 1,2, and 3 signed by the USAF (19 May 1998) ESD issued (May 2000)

4.2 REMEDIAL ACTION OBJECTIVES

The remedial action objective (RAO) identified in the ROD was to remove VOC and total

petroleum hydrocarbons (TPH) contamination from the unsaturated soils at IRP Sites 1, 2, and 3

to ROD cleanup standards.

4.3 REMEDY DESCRIPTION

The USAF currendy operates a SVE system for soil remediation at IRP Site 3. Remediation for

soil contaminants is complete at IRP Sites 1 and 2 as indicated in Table 4-1.

Table 4-1: IRP Sites 1, 2, and 3 Removal Action Status

AFP 44 Site ID

IRP Site 1

IRP Site 2

IRP Site 3

IRP Site ID

DP-OOl DP-002

DP-003

Site Name

Ranch Site

FACO Landfill

Inactive Drainage Channel Disposal Pits

iVIedium

S

S

S

Corrective Actions

SVE Complete

SVE Complete, Closure Pending SVE Operating

Scheduled to Complete

2000

2004

2004

Current Phase

CO

CO

RAO

Notes: CO DP FACO -IRP RAO S SVE

Close Out Disposal Pit Final Assembly and Check Out Installation Restoration Program Remedial Action Operation Soil Soil Vapor Extraction

L:\\roi-k\26616\»'oi-k^ProJnet''5-Yem ReviemFinahl-2-l\lneliiJes Client's Comments III-12-ll4\Finol 1-2-1 Five-Yr ROD CLRevie..2.<loe

4-1 October 2004


IRP Sites I. 2. and 3 Air Force Plant 44. Tucson. .Arizona


5.0 PROGRESS SINCE THE LAST FIVE-YEAR REVIEW

This is the first five-year review ofthe ROD for IRP Sites 1, 2, and 3. The signamre date for this

five-year ROD review is the trigger date for subsequent five-year reviews.

L:\m,rk\266S6Wotk\Ptoihet\5-YearRev'te.v\Finol\l .2-l \ lneli tJes Client's Comments UI-l 2.ll4SFinal 1-2-1 Five-Yr ROD CLRevien2.Joe Octobcr 2004

5-1


IRP Sites 1.2, and 3 Air Force Plant 44. Tucson, Arizona

Operable Unit 03 ofthe Tucson International A irport Area Superfund Site

6.0 FIVE-YEAR REVIEW PROCESS

6.1 ADMINISTRATIVE COMPONENTS

USEPA and ADEQ were notified ofthe initiation ofthe Five-Year Review on 15 May 2002.

George Warner, Remedial Project Manager (RPM) for AFP 44 Aeronautical Systems Center,

Acquisition Environmental, Safety and Health Division, Engineering Directorate, Wright-

Patterson Air Force Base, Ohio, leads the Five-Year Review Team. The team included

representatives from Raytheon Systems Conipany and Earth Tech. Craig Kafura and Bill Ellett

of ADEQ and Eugenia Chow, Sean Hogan, and Matthew Jefferson of USEPA Region 9 assisted

in the review as representatives for the regulatory oversight agencies. Attachment 4 contains a

Responsiveness Sumniary addressing the comments received from USEPA and ADEQ.

6.2 COMMUNITY INVOLVEMENT

The TIAA Superfund Site has a very active community board, the Unified Community Advisory

Board (UCAB), which meets every 2 months to discuss the current status ofall the TIAA project

areas, including AFP 44. Members ofthe UCAB were notified ofthe initiation ofthe first five-

year review of the ROD for IRP Sites 1, 2, and 3 on 19 November 2002. At that time, a

representative from Earth Tech presented an overview of the evaluation process, including a

brief description ofthe selected remedy, a sumniary of contamination addressed by the selected

remedy, how the community can contribute during the review process, a contact name and

telephone number for further infonnation, and the scheduled completion date of the first five-

year review. Addifionally, a representative of Earth Tech briefed the community on

14 January 2003 as to the progress and preliminary findings ofthe review.

6.3 DOCUMENT REVIEW

This five-year review consists of a review of relevant documents and information included in

Attachments 1 through 4. Documents reviewed included the ROD for IRP Sites 1, 2, and 3; the

ESD; the Final RI/FS and Risk Assessnient Reports for AFP 44; the Removal Action Completion

Report for IRP Site 1; documentafion of removal actions; and the Remedial Process

Optimization Study for AFP 44. Sources of applicable or relevant and appropriate requirements

L.'.uot-k-.26616\iyork\ProJttct'.5-YeorRevieu\Fillol',l-2-.l\lnelti,lesCltent's Comments l()-l2-(l4'.Fmal 1-2-1 Five-Yr ROD CLRevte.r2.iloe O c t o b e F 2 0 0 4

6-1


IRP Sites 1.2. and 3 Air Force Plant 44, Tucson, Arizona


(ARARs) were also evaluated, such as current soil cleanup levels published in Arizona

Environmental Statutes, regulafions published in the Federal NCP, and guidance published by

USEPA.

6.4 DATA REVIEW

This five-year review included an evaluation of relevant nionitoring data and confimiation

sampling results (see Attachments 1, 2, and 3). The types of data included SVE effluent data and

environmental remediation monthly nionitoring data. Sampling and nionitoring plans for IRP

Sites 1, 2, and 3, were reviewed in conjunction with the review ofthe results ofthe monitoring

data. Although no modeling was perfomied as part ofthis five-year review, results ofthe initial

modeling effort were reviewed to confimi that the levels calculated, which defined the clean-up

standards and operational success ofthe SVE systems, were appropriate.

6.5 SITE INSPECTION

Raytheon personnel regularly conduct site inspections at IRP Sites 1, 2, and 3 as part ofthe

ongoing operation and maintenance of the plant. Plant personnel inspect the operating SVE

systeni at IRP Site 3 for proper electrical and mechanical function and also to document the

condition of the three sites and the surroundings in general. Any deficiencies are corrected

promptly. No unauthorized activity at IRP Sites 1, 2, and 3 has been reported or observed. For

the first five-year review, USAF representatives and Earth Tech personnel inspected the sites and

the surrounding property for their overall condition. Inspections of the IRP Site 1 closeout and

the current configuration of soil remedial systems at IRP Sites 2 and 3 were conducted on

19 March 2003.

The AFP 44 perimeter fence controls access to the sites. Armed guards are stationed at the

entrances to AFP 44 and regular security patrols are performed. There is no other site-specific

security required by the final ROD. There are no access restricfions or physical controls, such as

caps or signs, in place as part ofthe final remedy for these sites.

L:\mnk\:6616\n'otVrioJliet- .5-Yeor Revien Finul\l-2-l ' . lnelttJes Client's Comtnents lll-l2-(l4'Final 1-2-1 Five-Yr ROD CLRevie>v2.Jt>e October 2004

6-2


IRP Sites 1, 2, and 3 .Air Force Plant 44, Tucson, Arizona

Operable Unit 03 ofthe Tucson International Airport Area Superfiind Site

6.6 INTERVIEWS

IRP project review meetings are held on a bimonthly basis for IRP Sites 1, 2, and 3. In addition,

community meetings (the UCAB) are also held on a bimonthly basis. Interviews with program

managers, regulatory representatives, local officials, and members ofthe community took place

at these scheduled meetings. Therefore, a separate interview tailored to evaluate the

effectiveness ofthe remedy and the stams of IRP Sites 1, 2, and 3 was deemed unnecessary.

The USAF conducted community interviews from January to March 2001 for the updated Draft

Community Relafions Plan for AFP 44 (Shaw Environmental & Infrastmchire 2002). These

interviews were evaluated to identify any issues related to the operations ofthe remedial systems

and are included in this five-year review by reference.

The community concems brought up during the Community Relations Plan interview effort

included the following themes. The first concem was that only those individuals with a long

history with the TIAA Superfund Site understand that various agencies and organizafions have

varying responsibilities for different parts of the site. The second concem was a need for

simpler, easier-to-understand communication. Typically no "big picture" is given of situations

and projects.

In addition, the interviews showed that those with ongoing communicafion with the USAF about

the AFP 44 cleanup like the informafion that they are receiving, other than the aforemenfioned

presentation issues, and are satisfied with the USAF's cleanup actions.

L:'..sork\26616'.ll'<nk'.PtoJitet\5-yearRevie,v\FinolM-2-j\lnelti.les Client's Comments l(l-l2-ll4tFn,ol 1-2-1 Five-Yr ROD CLRevieiv2.Joc Octobcr 2004

6-3


IRP Sites I. 2. and 3 Air Force Plant 44. Tucson, Arizona

Operable Unit 03 ofthe Tucson International A irport Area Superfiind Site

7.0 TECHNICAL ASSESSMENT

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

Answer A: Yes. The data and documents reviewed, site inspections, and monitoring activifies

indicate the SVE remedy for IRP Sites 1, 2, and 3 is functioning as intended by the ROD, as

modified by the ESD. The USAF has implemented recommendations to optimize the remedy

throughout the lifetime of the remedy. A comparison of estimated system durations and costs

from the ROD to actual durations and costs is provided in Table 7-1.

Tabic 7-1: System Duration and Costs for IRP Sites 1, 2, and 3

Site Number

IRP Site 1 IRP Site 2 IRP Site 3

ROD Estimates Remedial Timeframe

2 years 7 years 4 years

Cost $1,735,640 $7,980,354 $ 957,066

Actual Svstem Operations Remedial Timeframe

1996- 1997 1996-2000

1996-Ongoing

Cost (to date) * * *

Notes •Actual total cost for IRP Sites 1. 2. and 3 is S 10.379.784 through fiscal year 2003 (costs provided by Raytheon and Earth Tech). Costs are combined for the three sites because the design, iinplementation. and operation were contractually coinbined. Source: Earth Tech (1997).

There have been no changes in the physical conditions ofthe sites (i.e., geology or groundwater

levels) that would negatively affect the protectiveness of the remedy. Cleanup levels have been

attained at IRP Sites 1 and 2 and will be attained in the future at IRP Site 3. Remedial actions

have been completed at IRP Sites 1 and 2.

The selected and implemented SVE remedy for VOCs at IRP Sites 1, 2, and 3, has attained (or

will attain in the fiiture) the numeric and narrative cleanup levels oufiined in the ROD. This

cleanup standard states that "Each VOC contaminant concentration in soil at the IRP sites shall

be reduced to levels that do not cause or contribute to the upper divided regional aquifer

contamination in excess of each contaminant's Federal Safe Drinking Water Act Maximum

Contaminant Level (MCL) or State Aquifer Water Ouality Standard if there is no MCL. " The

ROD specified that the methodology to test compliance with the narrative standard would be

vadose zone (soils above the water table) and groundwater modeling as specified in the

Operation and Maintenance Manual for the selected remedy. Because the predominant VOC soil

L.-Work\26616\lk'ork\Pi-o,liiet\5-YeurRevie'r\Final\l-2-lilnelttJes Client's Onnments III-l 2-(l4\Fiiutl 1-2-1 Five-Yr ROD CLRev

7-1 October 2004


IRP Sites 1. 2, and 3 .Air Force Plant 44, Tucson, Arizona


contamination consists of TCE and 1,1-dichloroethylene (DCE), this methodology assigns these

two VOC contaminants to be used as indicator chemicals.

The detennination of compliance with the narrative clean-up standard in the ROD has been

accomplished using two models: T2V0C, a three-dimensional, multi-phase unsamrated zone

transport model; and MODFLOW SURFACT99, a two-dimensional, multi-phase model.

T2V0C was used to define the preliminary trigger values listed in Table 7-2. Residual VOCs in

unsaturated zone soil below the preliminary trigger level would not cause or contribute to

groundwater contamination in excess of the maximum contaminant level (MCL) for TCE.

Because TCE was the most prevalent contaminant at the site and had the most conservative

cleanup standard in groundwater, it was assumed that removal of TCE to levels below the trigger

value would result in reduction of the other VOCs present to levels below standards. This has

proven to be the case with the VOCs at IRP Sites 1 and 2. Compliance with the standard was

determined using MODFLOW SURFACT99 to predict potential future maximum groundwater

contamination levels beneath each site.

Preliminary trigger values for TCE in vapor were 9 micrograms per liter (i-ig/L) for IRP Site 1,

15 jig/L for IRP Site 2, and 42 jig/L for IRP Site 3 as shown in Table 7-2 (Earth Tech 2000b).

Groundwater modeling data show that at IRP Sites 1 and 2, where SVE is complete, the potenfial

maximum levels of TCE in groundwater would be below the MCL of 5.0 p.g/L, as shown in

Table 7-2.

Table 7-2: Preliminary Trigger Levels for TCE and Potential Maximuin Groundwater TCE levels for Sites 1, 2, and 3

TCE Standards

Preliminary Trigger Level

Potential Maximum TCE in groundwater

(^g/L) Sitei

9

4.79

Site 2

15

0.230

Site 3 1 42

Ongoing remediation

Question B: Are the exposure assumptions, toxicity data, cleanup levels, and RAOs used at the time ofthe remedy selecfion still valid?

L:\m.rk\26616\ll'o,-k\Pi-oJnet\S-YeorRevie..^Fi,uil'.l-2-l\lnelt„L-s Clknt 's Commenls lll-]2-ll4\Fimil 1-2-1 Five-Yr ROD CLRevieu-2.JoL

7-2 October 2004


IRP Sites I, 2, and 3 Air Force Plant 44. Tucson, Arizona


Answer B: Yes. Except for the ARAR change described below, the exposure assumptions,

toxicity data, cleanup levels, and RAOs used at each of the three sites are sfill valid. Current

monitoring data indicate that the remedy is functioning as required to remove VOC

contamination from the soil (unsamrated zone), such that the residual contamination will not

cause or contribute to the exceedance ofthe MCL in groundwater. Human and ecological risk

data were adequately addressed when the remedies were selected at IRP Sites 1, 2, and 3

(Earth Tech 1993). There are no new human or ecological pathways or receptors affecting the

risk assessnient. The only new inforination that may be "to be considered" criteria as to a human

health risk assessnient is the provisional reduction ofthe carcinogenic slope factor for TCE that

is presented in the USEPA Region 9 Preliminary Remediation Goals and the removal ofthe DCE

slope factor as recommended in the Integrated Risk Infomiation System (IRIS). However, the

off-gas from the operafing SVE systeni at IRP Site 3 is now treated with primary and secondary

carbon units so no emissions occur above the analytical method detection limit. As such, the

provisional TCE slope factors do not affect the protectiveness of the remedy at IRP Sites 1, 2,

and 3.

In May 2000, the USAF issued an ESD for IRP Sites 1, 2, and 3. As documented in the ESD,

there was a change in the cleanup levels for TPH in soil. After the ROD for IRP Sites 1, 2, and 3

was prepared, the State of Arizona promulgated soil remediation levels (SRLs) (Arizona

Administrative Code, Title 18, Chapter 7, Article 2, Appendix A) that were enforceable

standards. The SRLs for petroleum hydrocarbons (Cio to C32) are 4,100 mg/kg for residential

soils and 18,000 mg/kg for non-residential soils. In light ofthis regulatory change and to be

consistent with current Arizona State regulations for non-residential land use, it was appropriate

to redefine the cleanup standard for TPH at IRP Sites 1, 2, and 3. Table 7-3 outlines both the

original and revised chemical-specific ARARs for TPH.

L:\m>rk'.26616'iyork-Pt-o<liiet\5-Yeor Revieu-.Final.I-2-l'lneltiJes Client's Comments Id-12-(l4-.Finol 1-2-1 Five-Yr ROD C'LRevicu2.Joe Octobcr 2004

7-3


IRP Sites I, 2, and'3 .4ir Force Plant 44, Tucson, Arizona

Operable Unit 03 ofthe Tucson International Airport Area Supeifund Site

Table 7-3: Original and Revised Chemical-Specific ARARs and TBCs

Analyte

TPH

Original ARARs Presented in ROD Interim ADEQ Soil HBGL""

(mg/kg) Non-residential

24,500

Residential

7,000

Revised ARARs in ESD ADEQSRU"'

(mg/kg) Non-residential

18,000

Residential

4,100 Notes: (a) ADEQ "Human Health-Based Guidance Levels for Contaminants in Drinking Water and Soil." Arizona

Administrative Code, Title 18. Chapter 7, Article 2, Interim Soil Remediation Standards. (b) Arizona Administrative Code. Title IS. Chapter 7. Article 2. Appendi.x A. Soil Remediation Levels. December 1997.

In support of selection of non-residential cleanup standards, USEPA received a written

commitment from the USAF that:

" ...As long as the federal government owns AFP 44, the propert}' will be used for non-residential purposes. The Air Force will place a deed restriction upon AFP 44 when the property is sold or transferred per General Sen'ices Administration (GSA) direction that no federal agency shall place deed restrictions upon U.S. government owned property until the time of sale or transfer. " (USAF 2000)

Furthermore, consistent with the GSA directive and to ensure the appropriate use ofthe property

in the fiature, the USAF will place land use restrictions in any deed transferring ownership ofthe

plant to a non-Federal entity. Using the non-residential SRL of 18,000 mg/kg for the enforceable

soil cleanup standard for TPH, the current remedy offers continued protection, in accordance

with CERCLA Section 121.

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

Answer C: No. There is no new information that would impact the protectiveness ofthe remedy

for soils as selected in the ROD for IRP Sites 1, 2, and 3. However, evidence exists that a

samrated soil source of TCE at IRP Sites 2 and 3 will continue to contribute to groundwater

contamination until it is removed or otherwise controlled. Remedial activities under IRP Site 14

(AFRIMS Site OT013) and IRP Site 17 (AFRIMS Site OT012) are addressing this issue,

including pursuing technologies capable of remediating the source niaterial, such as potassium

permanganate injection.

L:\u-nrk\26616\ll 'oi-k\Ptit,ltiet\5-YearRevieu'Finol\l-2-l\hklti,les Clknt 's Comments 1(1-12-ll4\Finol 1-2.1 Ftve-Yr ROD CLReiieu 2 Joe

7-4 October 2004

Final First Five-Year Review of the Record qf Decision for Soil Cleanup qf

IRP Sites I. 2. and 3 Air Force Plant 44, Tucson. Arizona


8.0 ISSUES

Table 8-1 lists the issues raised in this first Five-year Review report for remedies at AFP 44 IRP

Sites 1, 2, and 3. Attachment 4 describes these issues in more detail.

Table 8-1: Issues Raised in Five-Year Review of AFP 44, IRP Sites 1, 2, and 3

Issue

IRP Site 2: TPH in soil at 15-20 feet bgs is above the cleanup level of 18,000 mg/kg. USAF will seek closure ofthe TPH portion of Site 2 using site-specific risk evaluation conducted by the ADEQ that allows the soil to be left in place. Groundwater at Sites 2 and 3: TCE is trapped in the Upper Clay Unit in the capillary fringe and below the top ofthe vvater table at Sites 2 and 3. This is not affecting the effectiveness ofthe soils remedy at IRP Sites 1, 2, and 3. This TCE source area was not addressed in the ROD for these sites. This issue is being addressed as part of IRP Sites 14 and 17 groundwater remedial actions.

Currently Affects Protectiveness

(Y/N)

N

N

Affects Future Protectiveness

(Y/N)

N

• N

„-k\26616'iyork\PioJtict\5-YeorRevieu-\Fimtl\l-3-l\lneltiJe.^ Clknt's Ctnntnents III-I2-(I4 .Final 1-2-1 Five-Yr ROD CLRevieiv2.Joe October 2004


IRP Sites 1,2, and 3 Air Force Plant 44, Tucson. Arizona


9.0 RECOMMENDATIONS AND FOLLOW-UP ACTIONS

Table 9-1 presents recommendations for each issue identified as potentially affecting the

protectiveness ofthe remedy currenfly or in the future as set forth in Table 8-1. This table

identifies the party responsible for implementing the recommendation.

Table 9-1: Recommendations and Follow-Up Actions at AFP 44, IRP Sites 1, 2, and 3

Issue

IRP Sites 2 and 3 - TCE source below the water table (not addressed in ROD).

Recommendations/ Follow-up Actions

Continue to perform remedial actions at IRP Site 17 (AFRIMS Site OTO 12).

Party Responsible

USAF

Oversight Agency

USEPA/ADEQ

Milestone Date

NA

Affects Protectiveness?

(Y/N)

Current

N

Future

N

L:\mn-k\26616\n'otk\Pt-oJiiet'.5-Yeitr Revicu'Fittitl'.l-2-.l:lnelitJes Cliettfs Cinnments HI-I2-IM\Finctl 1-2-1 Five-Yr ROD CLRe-

9-1 October 2004


IRP Sites 1. 2. and 3 Air Force Plant 44, Tucson. .Arizona

Operable Unil 03 ofthe Tucson International Airport Area Superfund Site

10.0 PROTECTIVENESS STATEMENT

The VOC-contaminated soil remedy (SVE) selected in the 1998 ROD for IRP Sites 1, 2, and 3 is

expected to be or is protective of huinan health and the environment. Exposure pathways that

could result in unacceptable risks are being controlled. There was no long-term monitoring

required in the ROD because the remedial actions involved source removal. Current nionitoring

data indicate that the soil remedy covered in the 1998 ROD is functioning as required to achieve

cleanup goals. Long-term protectiveness ofthe ongoing soil VOC remedy at IRP Site 3 will be

verified by obtaining additional groundwater samples as a part of ongoing IRP Site 17 Regional

Groundwater remediation.

L:\mnk\26616-..iyotk'.Pi-oJtiet\5-yeorRevteu-\Finol\l.2-l'..lneltiJesClknl's Comments lll-l2.ll4\Fimtl 1-2-3 Five-Yr ROD CLRevie.v2.Joe O c t o b c r 2 0 0 4

10-1


IRP Sites I, 2, and 3 .Air Force Plant 44. Tucson, Arizona


11.0 NEXT REVIEW

The next five-year review for AFP 44, IRP Sites 1, 2, and 3 is required five years from the date

of submittal ofthe Final Five-year review.

L.\i.ot-k\26616\»'ork\Pi-oJtkt\5-YeorRevie.v\Finol'J-2-}:lneh,Jes Client's Cinnments lll-l2-ll4'Fimil 1-2-1 Five-Yr ROD CLReviev 2 Joe Octotcr 2004

11-1


IRP Sites I, 2, and 3 Air Force Plant 44. Tucson, Arizona


12.0 REFERENCES

Arizona Department of Environmental Quality (ADEQ). 2003. Letter from William Ellett, ADEQ to Timothy Allen, Raytheon Company, regarding Site-Specific Risk Assessnient for TPH at IRP Site 2, Air Force Plant (AFP) 44, Tucson, AZ. March 7, 2003.

Air Force Center for Environmental Excellence. 1999. Air Force Remedial Process Optimization Handbook. Brooks United States Air Force Base, Texas.

ASC. 2001. Air Force Plant 44 Progress Report, Environmental Restoration Program.

Barackman, Martin. 2000. Errol L. Montgomery & Associates, personal communication. November 16, 2000.

Coulter, Glynis. 2000. Raytheon, personal communicafion. September 14, 2000. Tucson, Arizona.

EarthTech. 1992. Remedial Investigation Report, Prepared for Air Force Plant 44, Tucson Arizona. Tempe, AZ. July.

'—. \99i. Final Risk Assessment for Air Force Plant 44, Volumes I-II. August.

-. 1994a. A o Further Action Report for Site 7, Air Force Plant 44, Tucson, Arizona. September.

-. 1994b. No Further Acfion Report for Site 8, Air Force Plant 44, Tucson, Arizona. September.

-. 1994c. No Further Action Report for Site 9, Air Force Plant 44, Tucson, Arizona. September.

-. 1994d. No Further Action Report for Site 15, Air Force Plant 44, Tucson, Arizona-September.

-. 1994e. Remedial Investigation Report Attachment, Prepared for Air Force Plant 44, Tucson Arizona. Tempe, AZ. January.

-. 1995a. Final Feasibility Study Report, Volume 1, Prepared for Air Force Plant 44, Tucson Arizona. January.

1995b. Final Sites 1, 2, and 3 Non-Time Critical Removal Action Work Plan. Deceniber.

1995c. Engineering Evaluation/Cost Analysis, Overall Final, Prepared Air Force Plant 44. November.

L \wot-k',26616\tyork.Pi-oJiiet\5-Ye,irRevie\v',Foutl'l.2-l:.lneliules Clknt's Comments 1(1-12-(l4'.Finol 1-2-1 Ftve-Yr ROD CLRevie.vl Joe Octobcr 2004

12-1


IRP Sites 1,2, and 3 Air Force Plant 44, Tucson. Arizona

Operable Unit 03 of the Tucson International .A irport Area Superfund Site

. 1996. Remedial Investigation Report Attachment 2, Prepared for Air Force Plant 44, Tucson Arizona. December.

— . 1997. Final Record of Decision, Sites 1, 2, and 3, Air Force Plant 44, Tucson, Arizona. April (issued April 1997, signed by the USAF [9 May 1998]).

. 2000a. Final Explanation of Significant Difference IRP Sites 1, 2, and 3 Remedial

Action (includes Attachment 1: Site 1 Post-Remedial Soil Boring Results), AFP 44. May.

. 2000b. Final T2VOC Modeling Technical Approach. April.

. 2000c. Final Remedial Action Completion Report Site 1: Ranch Site, Air Force Plant 44, Tucson: Arizona. September. . 2000d. Final, Phase II EBS Investigation Report, AFP 44 (includes Attachment 1 Revised Addendum to the EBS for AFP 44. March.

. 2001. Draft Final, Remedial Process Optimization Phase II Report, Air Force Plant 44. December.

. 2003a. Final Removal Action Completion Report Site 2: Final Assembly and Checkout (FACO) Landfill, AFP 44. September.

. 2003 b. Final First Five-Year Review ofthe ROD for Soil Cleanup of IRP Sites 4, 5, and 6, Air Force Plant 44. October.

Errol L. Montgomery & Associates. 2000. Memorandum Report, Update of AFP 44 Groundwater Models and Simulation of Selected Well Field Operational Alternatives. March 14.

Metcalf and Eddy. 1995. AFP 44 Groundwater Treatment Plant Optimization.

Raytheon Systems Company. 2003. Summary of Reclamation Well Field NS Soil Remediation Operations-Data Report, July through December 2002, Air Force Plant 44, Tucson, Arizona. March 14.

Shaw Environmental & Infrastmcmre. 2002. Draft Community Relations Plan Update, AFP 44, Tucson, AZ. May.

United States Air Force. 1986. Final Air Force Plant 44 Remedial Action Plan Responsiveness Summaiy and Record of Decision. April.

. 2000. Letter from Dennis Scott, ASC/ENV, to Sean Hogan, USEPA, regarding EPA comments on the Explanation of Significant Difference (ESD) for Sites 1, 2, and 3, Remedial Action at Air Force Plant (AFP) 44, Tucson, AZ. April 27, 2000.

L. 'tunk\26616Wot-k\PtitJtiet\5-Yeur Rcvieu:Fimtl\l-2-.l'-JnclitJl-s Clknt's Commenls l(>-l2-(l4\Fin,il 1.2-1 Five-Yr ROD CLRevieu2.J„e Octobcr 2004

12-2

f I I I I I I I I I I I f

" " ^ ^ ^ « M ^ , , ,

ATTACHMENT 1

IRP SITE 1 DETAILED SITE REVIEW

Final Attachment I - IRP Site I Detailed Site Reviews First Five-Year Review ofthe

Record of Decision for Soil Cleanup of IRP Sites I. 2, and 3

Air Force Plant 44, Tucson. Arizona Operable Unit 03 ofthe Tucson

International Airport Area Superfund Site

IRP SITE 1 - RANCH SITE

1.0 CHRONOLOGY

Table IRP 1-1.1 lists the chronology of remedial action at Installation Restoration Program (IRP)

Sitei.

TABLE IRPl-1.1 CHRONOLOGY OF IRP SITE 1 REMEDIAL ACTION

Event

Drum burial site excavated as part of treatability study; EE/CA completed and submitted to USEPA and ADEQ Installation of SVE wells begun SVE/GAC system at IRP Site 1 operational Final ROD for IRP Sites 1, 2, and 3 submitted for signaUire SVE shut down; four quarters of monitoring initiated Quarterly vapor sampling at IRP Sites I, 2, and 3. ROD for IRP Sites 1, 2, and 3 signed by USEPA l" Quarter post-remediation vapor monitoring of IRP Site 1 wells 2'"' Quarter post-remediation vapor monitoring of IRP Site I wells ROD for IRP Sites 1,2, and 3 signed by ADEQ. 3"' Quarter post-remediation vapor monitoring of IRP Site I wells ROD for IRP Sites 1,2, and 3, signed by the USAF. 4'" Quarter post-remediation vapor monitoring of IRP Site 1 wells Performed confinnation soil borings with analysis for VOCs and TPH, installed new well (VM-118) to extract and monitor elevated VOCs Elevated levels of VOCs and TPH detected; SVE system reactivated Performed additional soil borings to characterize extent of TPH in soil and installed additional VM wells Performed 5"' post-remediation vapor monitoring of IRP Site 1 wells Final Explanation of Significant Difference (ESD) for IRP Sites 1, 2, and 3 submitted Final Remedial Action Completion Report for IRP Site 1 submitted and closure approval obtained

Date

November 1995

Januarv 1996 July 1996-August 1997 April 1997 August 1997-June 1998 September 1997 September 30, 1997 October 6-7, 1997 Januan,' 1998 January 6, 1998 April 1998 May 19, 1998 June 1998 March 10-11, 1999

March-July 1999 June-July 1999

January 2000 May 8, 2000 September 2000

Notes: EE/CA USEPA ADEQ SVE GAC ROD TPH VOC

Engineering Evaluation/Cost Analysis U.S. Environmental Protection Agency Arizona Department of Environmental Quality soil vapor extraction granular activated carbon Record of Decision total petroleum hydrocarbon volatile organic compound

IRP 1-1 October 2004

Final Attachment 1 - IRP Site 1 Detailed Site Reviews First Five-Year Review ofthe

Record of Decision for Soil Cleanup of IRP Sites 1,2. and 3

Air Force Plant 44. Tucson. Arizona Operable Unit 03 ofthe Tucson


2.0 BACKGROUND

IRP Site 1, the Ranch Site, encompasses approximately 32 acres located along the southem

boundary of Air Force Plant 44 (AFP 44). IRP Site 1 includes an inactive landfill. From

approximately 1952 to 1955, two unlined trenches located in the northern half of the site were

used as a general disposal area. During the remedial investigation (RI), additional disposal

trenches were identified (Earth Tech 1992). All trenches were graded and covered with nafive

soil in 1955.

Wastes known to have been disposed of in IRP Site 1 included machining coolants and

lubricants, trichloroethene (TCE), methylene chloride, spent solvents (not otherwise specified),

and paint sludge and thinners. Total petroleum hydrocarbon (TPH) contamination was also

present at the site. Fomier septic tank leachfields are also located in the northem half of IRP

Si te i .

2.1 BASIS FOR TAKING ACTION

The following volatile organic compounds (VOCs) were selected for human risk characterization

at IRP Site 1: carbon tetrachloride; Freon 113; tetrachloroethylene; TCE; and

1,1,1-trichloroethane (TCA). The following nietals in soil were selected for human and

ecological risk characterization: cadmiuni, copper, and zinc. According to the risk assessment,

no significant current or fumre impacts to human health and the environment from IRP Site 1

soil analytes were identified (Earth Tech 1993). Remediation ofthis IRP site was still proposed

because it had the potential to be a confinuing source of contamination to the drinking water

aquifer.

In addition to VOCs, TPH was idenfified in the Record of Decision (ROD) (Earth Tech 1997) as

being of concem at IRP Site 1. During the RI, buried dmms of lubricating and hydraulic oils

were discovered and removed. Soil samples collected following removal ofthe dmms indicated

elevated TPH levels in shallow soils up to 147,000 milligrams per kilogram (mg/kg). TPH

/.••:H„rl.'.:fif^>f.':H;i,/i 'rriuliff.i-ii-iirRcuc»^-f-i'iiill-:-Jllil>ii^l<m IRP 1-2 October 2004

Final Attachment I - IRP Site I Detailed Site Reviews First Five- Year Review ofthe

Record of Decision for Soil Cleanup of IRP Sites 1. 2, and 3



concentrafions exceeded regulatory cleanup levels presented in the ROD, which were not

promulgated standards at the time the ROD was prepared. The non-residential soil remediation

level (SRL) (18,000 mg/kg), which was promulgated after the ROD was issued, was ultimately

used as the soil cleanup standard for TPH at IRP Site 1 in accordance with the Explanation of

Significant Difference (ESD) (Earth Tech 2000a).


3.1 REMEDY SELECTION

Soil vapor extraction (SVE) with resin adsorption was selected as the remedy under the

Comprehensive Environmental Response, Compensation and Liability Act (CERCLA) for IRP

Site 1. Data collected during the first phase of SVE well installation at IRP Site 1 indicated that

the extent and magnitude of VOC-contaminated soil was much less than anticipated. Based on

this infomiation, the remedy was changed to include granular acfivated carbon (GAC) for vapor

treatment at IRP Site 1. This decision was based on treatability studies conducted under the

Feasibility Study (FS) (Earth Tech 1995a) and other documents in the administrative record.

The estimated cleanup duration for IRP Site 1 was 2 years.

The major components of the source control remedy selected for IRP Site 1 in the ROD

included:

• Installing SVE wells in contaminated soils above the water table (vadose zone).

• Exerting a vacuum on the wells to impose airflow through the contaminated soils. As air moved through the soils, the VOCs present in the vadose zone were stripped into the air stream.

• Piping the vapor stream to the ground surface. The withdrawn air was laden with volatilized contaminants, which were captured from the air stream by adsorption onto the GAC.

• Reducing TPH levels. The vapor movement and oxygenation of the soil profile also resulted in significant reductions in TPH levels at IRP Site 1. Although the selected

i .,,,,k-:(.6.i6'.iy,,ik.f',-,,,ii,,i-..i.y,.,iriiv.ie..-'Fii<.it.t-:-.i.iii.i.t<i'i.-iii.^-.ni.i.iii.i.-i!ii.j,. IRP 1 -3 October 2004



Air Force Plant 44, Tucson, .Arizona Operable Unit 03 ofthe Tucson


remedy was designed primarily to remove the VOCs from soil, it was also a viable technology to reduce the TPH levels through direct extraction and enhanced biological destmction as a result of increased oxygen levels in the vadose zone. In addition, natural attenuation processes assisted the SVE systeni in reduction of TPH levels in IRP Site 1 soils.

3.2 REMEDY IMPLEMENTATION

The United States Air Force (USAF) submitted a work plan for a non-time critical removal

action at IRP Sites 1, 2, and 3, an Engineering Evaluation/Cost Analysis (EE/CA), and a

Proposed Plan to the U.S. Environmental Protection Agency (USEPA) and the Arizona

Department of Environmental Quality (ADEQ) in September 1995. Implementation ofthe non-

time critical removal action to eliminate continuing sources of groundwater contamination and/or

to address potential risks to human health and the environment at IRP Sites 1, 2, and 3 began in

January 1996. The USAF signed the ROD for IRP Sites 1, 2, and 3 on 19 May 1998.

The SVE system consisted of 14 SVE wells; one 1,800 cubic foot per minute (cfm) blower; and

20,000-pound primary and 10,000-pound secondary carbon roll-offs. SVE wells and vapor

nionitoring wells were installed using air rotary techniques. Above-grade piping was installed,

with some underground road crossings, to convey vapors from the SVE wells to vapor treatment

areas. A GAC equipinent compound was installed for vapor treatnient. The vapor treatment

system was monitored for a variety of parameters during the startup period to ensure it was

operating properly and that a minimuni of 85 percent ofthe VOCs in the extracted vapor stream

were removed. Removal rates were generally better than 95 percent (Earth Tech 2000c).

3.3 SYSTEM OPERATION AND MAINTENANCE

The SVE system at IRP Site 1 operated from July 1996 through August 1997. Influent

concentrations at the blower went from 1,200 micrograms per liter (|ig/L) TCE at startup down

to 23 |ig/L in 1 year. During operation, the system removed approximately 6,888 pounds of

VOCs (Raytheon 2003) present at elevated levels in the vadose zone before achieving the

narrafive standard for VOCs defined in the ROD. As a screening tool for detennining

i.:..,„.k-.:66.^6.iy,.,.i.pr,„iii.i..-i-y.-«rii.-vie..--yiii.,t:i-:-.y.tti.i,im.-m:.iii.i.i,,.,-.« I lk: IRP 1 -4 October 2004

Final Attachment I - IRP Site I Detailed Site Reviews First Five- Year Review ofthe

Record of Decision for Soil Cleanup of IRP Sites I. 2. and 3

Air Force Plant 44, Tucson, .Arizona Operable Unil 03 ofthe Tucson

International Airport Area Supeifund Site

compliance with the narrative soil cleanup standard, a vadose zone transport model (T2V0C)

was used to define a preliminary trigger value of 9 jig/L TCE in vapor for IRP Site 1, below

which the residual VOCs in soil would not cause groundwater contamination in excess ofthe

maximum contaniinant level (MCL) for TCE.

After achieving the narrative standard, the system was taken off line and all vapor monitoring

wells were sampled for four consecutive quarters. During that year, no significant rebound was

observed. Vadose zone modeling resuhs indicated that IRP Site 1 was no longer contributing to

shallow groundwater contamination above the MCL. Specifically, a maximum of 4.8 |ig/L TCE

groundwater contamination was predicted approximately 75 years in the fumre (Earth Tech

2000c). Evaluation ofthe monitoring data indicated that no rebound had occurred and that final

confimiation sampling in a centrally located soil boring should be perfomied.

Confirmation sampling was conducted in March 1999. A soil boring (B118) was drilled on

10 and 11 March 1999. Vapor screening and laboratory analysis of soil samples from this boring

revealed slighfiy elevated levels of VOCs, as well as elevated TPH levels. Additional soil

borings were advanced near the first soil boring between 15 and 16 June 1999, to better define

the extent and magnitude of residual VOC and TPH contamination in the area. In response to

elevated VOCs in the soil borings, the SVE systeni was reactivated and additional monitoring

and soil vapor extracfion were conducted between 29 March and 30 July 1999. Supplementary

vapor nionitoring wells were installed between 18 August and 1 September 1999. After the

supplementary SVE operation period, the contaminant levels in wells were reduced to below

model-derived trigger values. Confirmation sampling of vapor wells completed on

20 September 1999 indicated no rebound (Earth Tech 2000c).

As an added measure of cleanup confirmation, a fifth post-remediafion vapor sampling event was

conducted in January 2000. Only 2 of 47 samples from SVE wells were greater than the T2V0C

model-derived trigger level for TCE (9.0 )iig/L in vapor). All of the DCE samples were below

detection limits. TCE was present above the trigger level at concentrations of 11 and 19 fig/L.

t.i...«*^'««.ili " i"J fr,**,.; i. ).•.,:• K.-r,.nit;n,;/,;..'...':.j/.,.,(im.™..W»,i.(im™/;.<*•• I R P 1 - 5 Octobcr 2004

Final Attachment I - IRP Site 1 Detailed Site Reviews First Five- Year Review ofthe

Record qf Decision for Soil Cleanup of IRP Sites I, 2. and 3

Air Force Plant 44. Tucson, Arizona Operable Unit 03 ofthe Tucson


These values are substantially below the highest value recorded at the end of SVE system

operation in August 1997.

Final vadose zone modeling of TCE using T2V0C was completed in 2000 using the post-

remediation vapor sampling data. Results indicate an estimated groundwater maximum

concentration of 4.79 |^g/L TCE was predicted approximately 10 years in the fumre. This

concentration is less than the MCL of 5.0 pg/L TCE. The modeling methodology and results

were reported in the Site 1 Final T2V0C Modeling Technical Approach (Earth Tech 2000b).

Based on the modeling results and the analytical findings, the remedial action for VOCs at IRP

Site 1 is considered complete. The blower at IRP Site 1 was relocated to IRP Site 5.

As agreed to by the USEPA and ADEQ, abandonment ofthe IRP Site 1 SVE wells as required

by the ROD will be perfomied at a fumre date. Upon completion of the well abandonment, the

site will be restored to a land use compatible with the immediately adjacent land, or as required

to accommodate production requirements.

Sampling and analysis conducted during 1999 demonstrate that the SVE remedy has

substantially reduced the TPH concentrations in soil. Two phases of confirmation soil boring

sampling were conducted from March to June 1999 and from August 1999 to September 1999.

Elevated TPH levels were identified during the March 1999 confirmation sampling event.

Subsequent sampling conducted in June, August, and September 1999 fully delineated the extent

of TPH in the soil. An ESD to the IRP Sites 1, 2, and 3 ROD established the non-residential

SRL of 18,000 mg/kg as the TPH cleanup criterion to allow IRP Site 1 to proceed toward

closure. Analytical results and cleanup options related to TPH at IRP Site 1 can be found in the

ESD. The current maxinium TPH concentration at IRP Site 1 is 13,500 mg/kg, which is at one

isolated point. Elevated TPH values are present only within a limited vertical and horizontal area.

The groundwater beneath and imniediately downgradient of IRP Site 1 shows no impacts from

petroleum hydrocarbons (Earth Tech 2000c).

i.;fl-ir,„jf„./„., s-y...,r«...i,.,.yi„.,i i-:-s-in.„i„.,.,„-.ui„.i,m.,« t ,*. I RP 1 -6 October 2004

Final Attachment 1 - IRP Site I Detailed Site Reviews First Five- Year Review ofthe

Record of Decision for Soil Cleanup qf IRP Sites 1. 2. a n d )

.Air Force Plant 44. Tucson. Arizona Operable Unit 03 ofthe Tucson

International A irport Area Superfund Site


This is the first five-year review for IRP Site 1.


Five-year reviews will continue to be required because TPH contaminafion remains onsite above

levels that allow for unlimited use and unrestricted exposure. The final submittal date of this

first five-year ROD review is the trigger date for subsequent five-year reviews.



Answer A: Yes. Remedial action is complete at IRP Site 1. Although two post-remediation

vapor samples exceeded the narrative cleanup standard, final modeling of TCE using T2V0C

indicated an estimated groundwater maximum concentration of 4.79 pg/L approximately 10

years in the fumre.

Question B: Are the exposure assumptions, toxicity data, cleanup levels, and remedial action

objectives (RAOs) used at the time ofthe remedy selection sfill valid?

Answer B: Yes. The exposure assumptions, toxicity data, and RAOs have not changed since

the remedy was selected. The cleanup levels have changed for TPH because ADEQ

promulgated new soil remediation levels in December 1997. This change is reflected in the ESD

(Earth Tech 2000a).

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

protectiveness ofthe remedy?

l.::..\,„h-:i.t,:.f,:.ty,„k.Fi;.li,.i:^.Y.;i,-R.-yi.-..-ti>uil:t-:..t:tii.ivli.n,-,ii..-:ni.i,h.ie'ii l.ilne IRP 1-7 October 2004

Final .Attachment 1 - IRP Site 1 Detailed Site Reviews First Five- Year Review ofthe

Record of Decision for Soil Cleanup of IRP Sites I, 2, and 3

.Air Force Plant 44, Tucson. .Arizona Operable Unit 03 of the Tucson


Answer C: The remedy for the unsamrated soils at IRP Site 1 has been successfiil and is

protective. No other information has come to light that could call into question the

protectiveness ofthe remedy for the unsamrated soils.

6.1 TECHNICAL ASSESSMENT SUMMARY

Soil vapor removal ceased and the SVE system was taken off-line in August 1997, when VOCs

in soil vapor fell below modeling-derived "trigger levels." In March 1999, slightly elevated TCE

levels were identified in a test boring (now VM-118) during a TPH post-remediation

confimiation sampling event. As a result, the SVE systeni was reactivated and vapor extraction

was perfomied for a period of six months, bringing TCE levels in VM-118 below trigger values

derived using T2V0C modeling. Four subsequent quarters of monitoring SVE wells confimied

the cleanup of VOCs across the remainder of the site, and confinned that VOC extracfion is

complete. The TPH cleanup standard (ADEQ SRLs for non-residential use) has also been met.

The removal acfion completion report for IRP Site 1 (Earth Tech 2000c) was finalized and

approved by USEPA and ADEQ in September 2000.

The selected remedy is protective of human health and the environment, complies with Federal

and State requirements that are legally applicable or relevant and appropriate to the remedial

action, and is cost-effective. The selected remedy utilizes pemianent solutions to the maximuni

extent practicable and satisfies the stamtory preference for remedies that employ treatment that

reduce toxicity, mobility, or volume as a principal element.

7.0 ISSUES

None.

I : .,.,t<.:f,f,^f,'.tV„,l.P^,Htl..l.i-Yl..l, R...i.-..-,hl,i„t t-:-i-iii..l,,n..„is.tii.,.fi,„..»i t . l . : IRP 1-8 October 2004

ATTACHMENT 2


Final .Attachment 2 - IRP Site 2 Detailed Site Reviews First Five-Year Review ofthe

Record of Decision for Soil Cleanup of IRP Sites 1, 2, and 3

.Air Force Plant 44, Tucson. Arizona Operable Unit 03. ofthe Tucson


Table IRP2-Site2.

IRP SITE 2 - FACO LANDFILL

1.0 CHRONOLOGY

lists the chronology of remedial action at Installation Restoration Program (IRP)

TABLE IRP2-1.1 CHRONOLOGY OF IRP SITE 2 REMEDIAL ACTION

Event EE/CA completed and submitted to USEPA and ADEQ; pilot study conducted on resin absorption Activities to implement the non-time critical removal action at IRP Site 2 initiated Resin absorption SVE system startup

, Final ROD for Sites 1, 2 and 3 submitted for signature. Quarterly vapor sampling at IRP Sites 1. 2 and 3. ROD for IRP Sites 1.2 and 3 signed by USEPA. ROD for IRP Sites 1,2 and 3 signed by ADEQ, ROD for IRP Sites 1, 2 and 3. signed by the USAF. Systems at IRP Site 2 shut down due to resin adsorption failure. Modifications to blowers completed for GAC operation and set up to extract from all open wells at IRP Site 2. SVE systems with GAC at IRP Site 2 restarted. Final Explanation of Significant Difference submitted for TPH contamination. SVE systems at IRP Site 2 are.shut down. Four quarters of shut-down monitoring begins. 1 ' Quarterly post-remediation vapor nionitoring of Site 2 wells

[ 2'"' Quarterly post-remediation vapor monitoring of Site 2 wells 3"* Quarterly post-remediation vapor monitoring of Site 2 wells 4''' Quarterly post-remediation vapor monitoring of Site 2 wells There is no evidence of significant rebound of TCE concenti-ations. Perfonned confirmation soil borings with analysis for TPH. Prepared draft Work Plan for in-situ remediation of TCE source with oxidation usino potassium permanganate (being evaluated under Site 17). Draft Removal Action Completion Report submitted. Submitted Draft Final Removal Action Completion Report with results of ADEQ site-specific risk assessment for TPH. Site Specific Risk Assessment for TPH at IRP Site 2 determines that TPH does not pose an unacceptable risk to human health for residential or non-residential uses. Final Removal Action Completion Report submitted to agencies.

Notes:

Date November 1995

January 1996 August 1996 April 1997 September 1997 September 30, 1997 January 6, 1998 May 19, 1998 August 1998

December 15, 1998 May 8, 2000 November 20, 2000

January 2001 April 2001 July 2001 October 2001

January 2002 September 2002

May 2002 Febniary 2003

March 7, 2003

September 2003

EE/CA USEPA ADEQ SVE ROD GAC TPH TCE USAF

Engineering Evaluation/Cost Analysis U,S. Environmental Protection Agency Arizona Department of Environmenlai Quality soil vapor extraction Record of Decision granular activated carbon total petroleum hydrocarbon trichloroethylene United States Air Force

fity.i.k-.J'nKli.vr.'.le. IRP 2-1 October 2004

Final Attachment 2 - IRP Site 2 Detailed Site Reviews First Five- Year Review ofthe

Record of Decision for Soil Cleanup of IRP Sites I. 2, and 3


International Airport Area Superfimd Site

2.0 BACKGROUND

IRP Site 2, the Final Assembly and Checkout (FACO) Landfill, is located near the southeast

comer of USAF Plant 44 (AFP 44). This site was active from approximately 1955 until the late

1960s or early 1970s. Studies and excavations at this 6.5-acre site indicate that wastes were

placed in six to eight unlined trenches or pits 6 to 7 feet deep and that open buming occurred in

the trenches. IRP Site 2 received liquid wastes consisting of flammable solvents; spent 1,1,1-

trichloroethane (TCA), trichloroethylene (TCE), and methylene chloride; machine coolants and

lubricants; paint sludges and thinners; and unidentified solvents and solids. Approximately

7.000 gallons of flammable liquids were disposed of at the site each week from 1955 through

1966. From 1955 until 1963, waste flammable liquids were bumed approximately four times per

week, and solids were bumed nightly. All buming activities at the FACO Landfill were

pennanently halted after 1963, although wastes continued to be placed in the landfill until the

late 1960s early 1970s. In 1980, a soil cover was placed over the landfill and the area was

seeded for vegetation.

Site investigation revealed total petroleum hydrocarbon (TPH) contamination was present at IRP

Site 2. The source is not specifically known, but releases from buried dmms of petroleum-based

coolants and lubricants are the suspected source.


The following volatile organic compounds (VOCs) were selected for human risk characterization

at IRP Site 2: benzene, chloroform, ethylbenzene, Freon 113, methylene chloride,

tetrachloroethylene, toluene, total xylenes, trans-1,2-dichloroethy Iene (DCE), TCE, vinyl

chloride, 1,1-dichloroethane (DCA), 1,2-DCA, 1,1-DCE, 1,1,2,2-tetrachloroethane, and 1,1,1-

TCA. No metals in soil were selected for human or ecological risk characterization. According

to the risk assessnient, no significant impact to human health and the environment for IRP Site 2

soil analytes was identified (Earth Tech 1993). Although there were no unacceptable risks for

organic soil contamination, the USAF elected to remediate IRP Site 2 soils based on historic site

/,.. i-M.s6tt„,i.i'„,ii,.,.!-Y..,„K..,,...,.n,i.,t.t.:-.s.iii„,ti.n.if..-.iii,i,ii..,.,i,:..!.. IRP 2-2 October 2004

Final Attachment 2 - IRP Site 2 Detailed Site Reviews First Five-Year Review of the


Air Force Plant 44, Tucson, Arizona Operable Unit 03 ofthe Tucson

International Airport .Area Superfund Site

practices and the potential that TCE in soil could be a continuing source of contamination to the

drinking water aquifer.

In addition to VOCs, TPH was identified in the Record of Decision (ROD) (Earth Tech 1997) as

being of concem at IRP Site 2. Soil samples collected following removal of the dmms of

petroleum-based coolants and lubricants indicated elevated TPH levels in shallow soils up to

43,000 milligranis per kilogram (mg/kg). TPH concentrations exceeded regulatory cleanup

levels presented in the ROD, which were not promulgated standards at the time the ROD was

prepared. The non-residential soil remediation level (SRL) (18,000 mg/kg), which was

promulgated after the ROD was signed, was ultimately used as the soil cleanup standard for TPH

at IRP Site 2 in accordance with the Explanation of Significant Difference (ESD)

(Earth Tech 2000a).



Soil vapor extraction (SVE), with resin absorption units for VOC capmre, was selected as the

remedy for IRP Site 2. This systeni was primarily designed to address the VOCs present in the

vadose zone, which were deterniined during the remedial investigation (RI) to be the

contaminants of greatest concern. SVE removes the VOCs trapped in pore spaces between soil

particles by drawing a vacuum at extraction wells. The withdrawn air is laden with volatilized

contaminants, which are capnired on the surfaces of resins by adsorption. The vapor movement

and oxygenation ofthe soils during SVE operation was anticipated to reduce TPH levels at IRP

Site 2. The ROD estimated project duration for soil remediation at IRP Site 2 to be

approximately 7 years.

The SVE with resin adsorption system experienced chronic mechanical problems, which caused

elevated operation and maintenance (O&M) costs. For this reason, as well as the reduced VOC

t.y.,„rk :hi,M,.ty,irk yn.ii,,i:i-y..„ H..v,i.„'yi„„i.i-:-.y.ut.i,t,m.-in. .iihi,ii.ti IRP 2-3 October 2004


Record of Decision for Soil Cleanup of IRP Sites 1, 2. and 3



concentrations in the air stream at IRP Site 2 after the first 2 years of operation, the resin

adsorption systems were replaced with granular activated carbon (GAC) systems in 1998.

The major components of the source control remedy selected for IRP Site 2 in the ROD

included:

• Installation of vapor extraction wells in contaminated soils above the water table (vadose zone).

• Exertion ofa vacuum on the extraction wells to impose airflow through the contaminated soils. As air moves through the soils, the VOCs present in the vadose zone are stripped into the air stream.

• Withdrawal ofthe vapor in the extraction wells to the ground surface. The withdrawn air is laden with volatilized contaminants, which are capmred from the air stream by adsorption onto the adsorption units or GAC.

3.2 REMEDIAL IMPLEMENTATION

The USAF submitted a work plan for a non-time critical removal action at IRP Sites 1, 2, and 3,

an Engineering Evaluation/Cost Analysis (EE/CA), and Proposed Plan to the United States

Environmental Protection Agency (USEPA) and the Arizona Department of Environmental

Quality (ADEQ) in September 1995. Implementation ofthe non-time critical removal action to

eliminate continuing sources of groundwater contamination and/or to address potential risks to

human health and the environment at IRP Sites 1, 2, and 3 began in January 1996. The USAF

signed the ROD for IRP Sites 1, 2, and 3 on 19 May 1998. The SVE system at IRP Site 2 was

installed in the spring of 1996 and began operations in August 1996. In December 1998, a GAC

system replaced the resin adsorption system. The GAC system began operating in December

1998. This system operated through November 2000, when the entire SVE system was taken off

line and shut down and quarterly monitoring began.

IRP Site 2 had the largest SVE systeni at AFP 44, with 219 individual well strings tied to five

vapor extraction and treatnient compounds with a total flow capacity of over 12,000 cubic feet

t:..,.rr..'«6.ifl.ir,„*rr,,,/,,,;'.i-i,,,.,«.wo,if,,,.j;,:...u«,,./,.».,,,,..Li.,,,,;,m,,.n.'.,/,., I R P 2 - 4 October2004


Record of Decision for Soil Cleanup qf IRP Sites I, 2, and 3



per minute (cfm). Vapor treatment at IRP Site 2 was initially accomplished using resin

adsorption units that condensed solvents from the vapor stream, allowing a portion of the

recovered TCE to be recycled. The resin adsorption systems were very effective at recovering

VOCs from the extracted vapors, but a mixmre of water vapor and free chlorine in the treatment

vessels caused hydrochloric acid to form, which subsequently corroded critical system parts. As

a result, the USAF replaced the resin absorption system with GAC.


The IRP Site 2 SVE systeni was effective as demonstrated by a dramatic decrease in influent

TCE concentrations at the blower between 1996 and 1998 as shown in Table IRP2-3.1.

TABLE IRP2-3.1 IRP SITE 2 INFLUENT TCE CONCENTRATIONS

SVE System Component

2VI

2V2

2V3

2V4

2V5

Influent TCE Concentrations

1996 Startup

1,100 ng/L

3,100 ^tg/L

3,400 ng/L

1,500 ng/L

8,800 ng/L

June 1998

8 ng/L 15 ng/L

350 ng/L 260 ng/L 210 ng/L

The IRP Site 2 SVE system renioved approximately 75,993 pounds of VOCs (Raytheon 2003)

before achieving the narrative standard for VOCs defmed in the ROD. In accordance with the

IRP Sites I, 2, and 3 ROD, the systeni was shut down and vapor-monitoring wells were sampled

for four consecutive quarters. The fourth and final quarterly monitoring event was conducted in

the fall of 2001 (Earth Tech 2003a).

As a screening tool for determining compliance with the narrative soil cleanup standard, a

vadose zone transport niodel (T2V0C) was used to define a preliminary trigger value of

15 micrograms per liter (fig/L) TCE in vapor for IRP Site 2, below which the residual VOCs in

soil would not cause groundwater contamination in excess of the maximum contaminant level

i..,„.„k':t,/..if'.ty.i>k-rr,.,ii,ei-..^-y,iii n.-,i,:,-Fi,iiit:i-:-.i.iii.i.iii'i, -nui.ii.m-.ii :.i„.. IRP 2-5 October 2004


Record of Decision for Soil Cleanup of IRP Sites 1. 2. and 3

.Air Force Plant 44. Tucson. .Arizona Operable Unit 03 ofthe Tucson


(MCL) for TCE. The final detemiination of compliance with the narrative standard in the ROD

was accomplished using MODFLOW SURFACT99, a two-dimensional, unsaturated zone

transport model.

During the fourth and final post-remediation vapor sampling events in October 2001, 3 of 226

vapor samples contained TCE at concentrations greater than the T2V0C model-derived

preliminary trigger level of 15 pg/L in vapor; all ofthe DCE samples were below the detection

limit. The TCE concentrations present ranged from 18 to 26 )ag/L. Because these values were

substantially below the highest value recorded when the systeni was taken off line in November

2000, the USAF took no special acfion in response to the exceedances. Final vadose zone

modeling of TCE with MODFLOW SURFACT99 has been completed. Results indicate a

maximuni groundwater concentration of 0.230 )-tg/L TCE was predicted approximately 30 years

in the future (Earth Tech 2002). The final modeling results and the analytical findings indicate

the remedial action for VOCs at IRP Site 2 is complete (Earth Tech 2003a).

An ESD to the IRP Sites 1, 2, and 3 ROD established the ADEQ non-residential land use SRL

level of 18,000 mg/kg as the cleanup standard for TPH contamination in soil at IRP Site 2. A

confirmatory soil boring (SCB 2-1) advanced on 9 January 2002 showed a maximum TPH

concentration at IRP Site 2 of 22,000 mg/kg at 15 feet below ground surface (bgs) (Earth Tech

2003a). The area of IRP Site 2 where TPH was above 18,000 mg/kg is small, and the elevated

levels occurred at approximately 15 feet bgs. Due to depth to groundwater (i.e., 160 feet), the

data showing no impacts to groundwater from TPH, and the lack of a complete exposure

pathway, the USAF requested a risk-based variance from the ADEQ SRLs. In March 2003,

ADEQ found that residual risk from TPH does not pose an unacceptable risk to human health for

residenfial or non-residential uses (ADEQ 2003). The USAF will leave the TPH contaminafion

in place and implement a long-tenn nionitoring program to ensure that no future impacts to

groundwater occur.

/, :.,i.rk.:66.;6 n-,„i foniii.1.1.y.-,i> kw,..,.'Ii„.ii.t-:-.i-.tii,„iim IRP 2-6 October 2004

Final Attachment 2 - IRP Site 2 Detailed Site Reviews First Five-Year Review of the


-Air Force Plant 44, Tucson, Arizona Operable Unit 03. ofthe Tucson

International .A irport Area Superfund Site


This is the first five-year review for IRP Site 2.


VOC contaminants above required cleanup levels were removed from the soil at IRP Site 2.

However, five-year reviews will continue to be required because TPH contaminants remain on-

site above levels that allow for unlimited use and unrestricted exposure. The final submittal date

ofthis first five-year ROD review is the trigger date for subsequent five-year reviews.



Answer A: Yes. Remedial action for soil is complete at IRP Site 2. Although three post-

remediation vapor samples exceeded the narrative standard, final vadose zone modeling of TCE

using MODFLOW SURFACT99 indicated an estimated groundwater maximum concentration of

0.230 nig/L TCE was predicted approximately 30 years in the future.


objectives (RAOs) used at the time ofthe remedy selecfion still valid?

Answer B: Yes. The exposure assumptions, toxicity data, and RAOs have not changed since

the remedy was selected. The cleanup levels have changed for TPH because ADEQ

promulgated new soil standards in December 1997. This change is reflected in the ESD for IRP

Sites 1, 2, and 3 (Earth Tech 2000a).

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

protectiveness of the remedy?

Answer C: No. The remedy for the unsaturated soils at IRP Site 2 has been successful and is

protective. No other information has come to light that could call into question the

/, i.:M.J6,u,„»/',-,„/,„..i.),-..,«,,,v„:f„,.,//.:,.i:.i«.„;,m,,»....i»,.,(,., ,:.</„. I R P 2 - 7 October 2004


Record of Decision for Soil Cleanup of IRP Sites 1,2. and 3

Air Force Plant 44, Tucson. .Arizona Operable Unit 03 ofthe Tucson


protectiveness ofthe remedy for unsamrated soils. While the remedy as selected in the ROD for

IRP Sites 1, 2, and 3 is protective, in general, groundwater contaminafion beneath IRP Site 2 is

ongoing because of the presence of TCE source areas trapped in the upper clay unit in the

capillary fringe and below the top of the water table (saturated zone). New wells have been

installed as part of an extended pilot treatment of TCE-contaminated saturated soils using

potassium permanganate. This pilot is being executed as part of the IRP Site 17, regional



Four quarters of monitoring SVE wells confimied the cleanup of VOCs in unsamrated zone soils

across the site, and modeling results indicate that soil vapor extraction is complete at IRP Site 2.

The state reviewed data indicating TPH concentrations above ADEQ non-residential SRLs and

determined the TPH poses no unacceptable risk. The removal action completion report was

finalized in September 2003 and is awaiting regulatory approval.

7.0 ISSUES

Due to depth to groundwater (i.e., 160 feet), data showing no impacts to groundwater from TPH,

and the lack of a complete exposure pathway, an ADEQ site-specific risk assessnient shows no

unacceptable risk to human health for residential or non-residential uses at this site (ADEQ

2003). The USAF has requested in its Final Removal Action Completion Report for IRP Site 2

an exception to the ADEQ SRLs (non-residential levels) for TPH using the risk-based standard.

The USAF will leave the TPH in place and implement a long-term monitoring program to ensure

that no future impact to groundwater occurs.

i.:'.i..,rk-.:6f,:i6-.iy,„k.fnHti,.i-'i-y.-.i'R.-.i.-..-'H'i'it i-:-.t.tii.i,ii,ii...,i.-in,i.ii.ii.-.ii :.(t.. IRP 2-8 October 2004

ATTACHMENT 3


Final Attachment 3 -IRP Site 3 Detailed Site Reviews First Five- Year Review ofthe

Record qf Decision for Soil Cleanup qf IRP Sites 1, 2. and 3

.Air Force Plant 44. Tucson. .Arizona Operable Unit 03 ofthe Tucson


IRP SITE 3 - INACTIVE DRAINAGE CHANNEL DISPOSAL PITS

1,0 CHRONOLOGY

Table IRP3-1.1 gives the chronology of remedial action at Installafion Restoration Program

(IRP) Site 3.

TABLE IRP3-1.1 CHRONOLOGY OF IRP SITE 3 REMEDIAL ACTION

Event

EE/CA completed and submitted to USEPA and ADEQ; pilot study conducted on resin absorption SVE/GAC system installed System startup Final ROD for IRP Sites 1, 2. and 3, submitted for signature. Quarterly vapor sampling at IRP Sites 1, 2, and 3, ROD for IRP Sites 1, 2, and 3, signed by USEPA, ROD for IRP Sites 1, 2, and 3, signed by ADEQ. Three new SVE vvells added ROD for IRP Sites 1,2, and 3, signed by the USAF. Six more SVE wells drilled; four connected to the SVE system. SVE system continues operations

Date November 1995

Spring 1996 October 1996 April 1997 September 1997 September 30, 1997 January 6, 1998 May 1998 May 19, 1998 January 2000 Present

Notes: EE/CA . USEPA ADEQ SVE GAC

Engineering Evaluation/Cost Analysis U.S. Environmental Protection Agency Arizona Department of Environmental Quality soil vapor extraction manular activated carbon

2.0 BACKGROUND

IRP Site 3, the Inactive Drainage Channel Disposal Pits, encompasses approximately 78 acres

and is located in the north-central portion of Air Force Plant 44 (AFP 44). The unlined

excavated pits were used primarily for solvent disposal. However, one area was used for

containerized liquid waste burial. The pits averaged 8 to 10 feet in diameter. They received

wastes from 1966 to 1977 and were subsequenfiy filled with soil. An examination of aerial

photographs suggests the number and size of the pits varied over time. The exact location of

some disposal areas is unknown. Wastes placed in the IRP Site 3 disposal pits included 1,1,1-

/.. ......„k-:MII' ty„ik Pr„,l„. ! S-Y.,ir li...;..,.. F,,,.,!!-: IRP3- October 2004




International Airport .Area Superfund Site

trichloroethane (TCA), trichloroethylene (TCE), methylene chloride, other solvents, and paint

sludges and thinners.


During the remedial investigation (RI), metals (cadmiuni, chromium, copper, nickel, and zinc)

were detected above background levels in IRP Site 3 soil samples (Earth Tech 1995a). A risk

assessnient for IRP Site 3 detemiined that there was no unacceptable risk for known or suspected

carcinogens. However, future excavation workers at IRP Site 3 could experience adverse

noncarcinogenic effects caused by inhalation of chromium-contaminated dust. Ecological

receptors were at potential risk at IRP Site 3 as well (Earth Tech 1993). The likely sources ofthe

nietals contamination detected in the soil in IRP Site 3 were the surface impoundments (IRP Site

4) and the drainage ditch (IRP Site 6), vvhich overlay Site 3. Remediation of IRP Sites 4 and 6

included removal of metal contamination at IRP Site 3, thus addressing the metal risk identified

initially in the risk assessment for IRP Site 3.

The following volatile organic compounds (VOCs) were selected for human risk

characterization: carbon tetrachloride, Freon 113, tetrachloroethylene (PCE), 1,1-dichloroethane

(DCA), 1,1-dichloroethylene (DCE), TCE, and 1,1,1-TCA. The compound

bis(2-ethylhexyl)phthalate also was selected for evaluation as an organic conipound in soil.

Although there was no unacceptable risk from organic soil contamination, the United States Air

Force (USAF) elected to remediate IRP Site 3 soils based on historic site practices and the

potential that TCE in soil could be a continuing source of groundwater contamination to the

drinking water aquifer.

Total petroleum hydrocarbons (TPHs) were not a concem for IRP Site 3 because maximum TPH

levels in soils of 167 milligrams per kilogram (mg/kg) were below applicable or relevant and

appropriate requirements (ARARs) presented in the Record of Decision (ROD)

(EarthTech 1997) and in accordance with the Explanation of Significant Difference (ESD)

(Earth Tech 2000a).

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Record of Decision for Soil Cleanup of IRP Sites 1. 2. and 3


International Airport Area Superfiind Site



Based on the findings of the RI/Feasibility Smdy (FS) and subsequent discussions, soil vapor

extraction (SVE) with resin adsorption was initially selected as the remedy for IRP Site 3.

However, based upon revised estimates of contaminated soil volume made during system

installation, SVE with granular activated carbon (GAC) was later selected as the final remedy.

This system was primarily designed to address the VOCs present in the vadose zone, which were

detemiined to be the contaminants of greatest concem. The air movement and oxygenation of

the soil also resulted in significant reductions in TPH levels.

The ROD required the USAF to remediate soil to narrative levels. As a screening tool for

determining compliance with the narrative soil cleanup standard, a vadose zone transport model

(T2V0C) was used to define a preliminary TCE trigger value of 42 micrograms per liter (|.tg/L)

in vapor for IRP Site 3, below which the residual TCE in soil would not cause groundwater

contamination in excess of the maximum contaminant level (MCL) for TCE.

The major components ofthe source control remedy selected in the ROD and the ESD included:

• Installation of extraction wells in contaminated soils above the water table (vadose zone).

• Exertion ofa vacuum on the wells to create airflow through the contaminated soils. As air moves through the soils, the VOCs present in the vadose zone are stripped into the air stream.

• Withdrawal ofthe VOC/air stream to the ground surface. The withdrawn air is laden with VOCs, which are capmred from the air stream by adsorption onto the GAC.

3.2 REMEDIAL IMPLEMENTATION

The USAF submitted a work plan for a non-time critical removal action at IRP Sites 1, 2, and 3,

an Engineering Evaluation/Cost Analysis (EE/CA), and Proposed Plan to the United States

Environmental Agency (USEPA) and the Arizona Department of Environmental Quality

(ADEQ) in September 1995. Implementation ofthe non-time critical removal action to eliminate

l.:-.,,.,ik.:66S6.tr,.rk-,Pr,,,li,.i,!.y,..,rKru,.,,:Fi,,,il.l.:.i.lii.,.t,,n..,i,.tn,,,t,m..,,iJ.,k,. IRP 3-3 Octobcr 2004


Record of Decision for Soil Cleanup qf IRP Sites I, 2. and 3

Air Force Plant 44. Tucson. .Arizona Operable Unit 03 ofthe Tucson

International Airport Area Superfiind Site

continuing sources of groundwater contamination and/or to address potential risks to human

health and the environment at IRP Sites I, 2, and 3 began in January 1996. The USAF signed

the ROD for IRP Sites 1, 2, and 3 on 19 May 1998. The SVE with GAC system at IRP Site 3

was installed in the spring of 1996 and has operated from October 1996 to date. The system

currently has 15 triple completion wells (3 casings per borehole) and 1 well with a single casing

(E-19) connected to the system. There are a total of 46 extraction points at 130 feet below

ground surface (bgs). The IRP Site 3 SVE system currently has a 20,000-pound primary GAC

unit, a 1,000-pound secondary GAC unit.

IRP Site 3 has proven to be the most enigmatic ofthe three SVE sites addressed in the ROD for

IRP Sites 1, 2, and 3. The VOC mass removal was impressive during the first 3 years of

operafion, and continues to remove additional solvent mass each month. In some perimeter well

strings, concentrations rose during 1997 and 1998, and sampling during off-line periods provided

evidence that the VOC source was not within the confines ofthe SVE well network. Additional

SVE wells were installed in 1998 and 2000 to enhance VOC recovery along the system

perimeter and to better define the maximuni extent of the contaminated soils. During this

operational period, the systeni has removed an estimated 12,977 pounds of VOCs (Raytheon

2003) with no estimated completion date to achieve site closure. The ROD estimated the project

duration for soil remediation at Site 3 to be 4 years.


IRP Site 3 has an SVE system that extracts VOCs from soil in a suspected source area using an

air stream, treats the VOCs in the air stream using GAC, and then discharges the purified air

(off-gas) from the GAC treatment system. Remedial activities are ongoing at IRP Site 3 and are

operating successfully. In October 1996, start-up influent VOC concentrations were 1,071 )ig/L

for TCE and DCE. In October 2003, influent concentrations were less than 10 f.ig/L. The SVE

system will continue to operate until the narrative soil cleanup standards are achieved. The

determination of compliance with the narrative standard will be accomplished using vadose zone

contaminant fate and transport modeling (MODFLOW SURFACT99).

i.....,,,i,...-M.ti,iy,.,ti'.,.i,i,ri-ye.,rit.,...,..-n,i.j.i.:..!-.i,i.:i,,n.-„i..t„.,.im.,„.i,t,. IRP 3-4 October 2004

Final .Attachment 3 -IRP Site 3 Detailed Site Reviews First Five- Year Review ofthe


Air Force Plan! 44, Tucson. .Arizona Operable Unit 03 ofthe Tucson


In 2001, the Remedial Process Opfimization Study (RPO) (Earth Tech 2001) evaluated Site 3 in

year 5 of its operation to detennine if off-gas treatnient using GAC was still necessary on the

SVE systeni. TCE and 1,1-DCE were assessed. Two air dispersion models were used to

detemiine VOC concentrations in air around the remediation systems and at the closest down

wind property line (located to the northeast). For the evaluated arrangement (GAC with no

stack) at IRP Site 3, the RPO determined that the TCE screening emission rate, which is the

maxinium emission rate that shows no unacceptable health risks, should be less than 0.65 pg/L

for onsite workers and less than 1.59 pg/L for offsite receptors at the eastem property boundary.

SVE off-gas nionitoring showed risk based on the average nionitoring concentration of

4.64 pg/L. Therefore, the RPO recommended the addition ofa 20-foot stack, thereby increasing

the allowable SVE off-gas concentration to 21.57 pg/L (Earth Tech 2001).

Further review of off-gas monitoring during this review showed that the only time risk occurs is

when there is breakthrough of the GAC, at which time the USAF shuts down the system and

replaces the carbon. To prevent any breakthrough in the future, the USAF has added a secondary

carbon unit to the systeni, after GAC treatnient.


This is the first five-year review at IRP Site 3.


Because VOC contamination is sfill actively being renioved and contaminants remain at levels

that do not pemiit unrestricted use ofthe property at IRP Site 3, a second five-year review will

be required to ensure protection of human health and the environment has been achieved. The

final submittal date of this five-year ROD review is the trigger date for subsequent five-year

reviews.

/.. ..,,.,.1 :t'f'.t6tV..,t.-Pii„ti,.l :-. y..„r k..vi..„ :yi„„t.l-:-.;-lli„.l„nL.,il...lliu.t,m,.„t S ,1,. IRP 3-5 October 2004



Air Force Plant 44. Tucson, .Arizona Operable Unit 03 ofthe Tucson

International A irport A rea Supeifund Site



Answer A: Yes. To date, the SVE systeni has removed an estimated 12,977 pounds of VOCs

(Raytheon 2003). October 2003 influent vapor concentrations were less than 10 pg/L, which is a

significant reduction from 1,071 pg/L at startup in 1996. The SVE system will continue to

operate until the narrative soil cleanup standard of less than 42 pg/L in vapor is achieved for all

Site 3 SVE wells. The detennination of coinpliance with the narrative standard will be

accomplished using vadose zone contaminant fate and transport modeling (MODFLOW

SURFACT99).

Air modeling ofthe IRP Site 3 SVE system indicated risk from contaminants in the vapor stream

discharged after the GAC. This occurred only during a brief period at breakthrough. As an

added measure, the USAF installed a new secondary carbon unit after the GAC unit at IRP Site

3.


objectives (RAOs) used at the time ofthe remedy selection still valid?

Answer B: Yes. The selected remedy is protective of human health and the environment,

complies with Federal and State requirements that are legally applicable or relevant and

appropriate to the remedial action, and is cost-effecfive. The selected remedy utilizes pemianent

solutions to the maximum extent practicable and satisfies the statutory preference for remedies

that employ treatment that reduces toxicity, mobility, or volume as a principal element. A

second five-year ROD review will be conducted to ensure protection of human health and the

environment continues to be achieved.

Question C: Has any other infomiation come to light that could call into question the

protectiveness ofthe remedy?

t. ,..,rt :6r,.lt-.ll,,rk-Pi..,lmi'<-y.-,irl>eri.-.,.Fi,i,il.t-:--t-.lii,i,t,i,i.-m,'-lti„.l,.m-,ii-!.,t,.v IRP 3-6 October 2004

Final Attachment 3 -IRP Site 3 Detailed Site Reviews First Five-Year Review ofthe

Record qf Decision for Soil Cleanup of IRP Sites 1. 2. and 3

Air Force Plant 44. Tucson. .Arizona Operable Unit 03 ofthe Tucson


Answer C: The remedy for the unsamrated soils at IRP Site 3 is operating successfully and is

protective. No other inforniation has come to light that could call into question the

protectiveness ofthe remedy for the unsaturated soils.

Groundwater contamination beneath IRP Site 3 is ongoing due to the presence of TCE source

areas and possibly non-aqueous phase liquid (NAPL) in the samrated zone. This saturated zone

source niaterial is being addressed in pilot studies conducted under the IRP Site 17 regional



Modeling results and the analytical findings indicate that the SVE system for the remediation of

VOCs in unsaturated soil at IRP Site 3 is operating in accordance with the ROD. Cleanup of

VOCs in soil at IRP Site 3 will continue to ensure that protection of human health and thc

environment has been achieved. There is no estimated completion date to achieve site closure.

7.0 ISSUES

The RPO recommended a 20-foot increase in height of emissions (from 1.5 to 21.5 feet), thereby

eliminating the potential of human health risk to on-site and off-site receptors (Earth Tech 2001).

Further review of off-gas monitoring showed that the only time that risk occurs is when there is

breakthrough of the GAC, at which time the USAF shuts down the system and replaces the

carbon. To prevent any breakthrough in the future, the USAF has added a secondary carbon unit

to the system.

,ik-::6616\ll.,i-k-Fn,tli„i...V)e,irH.-.i.-.,;Fiii.il.l-:-.l-]ii,iiliiii.-ins-.lii.',l!iiieiiil,k„ IRP 3-7 Oclober 2004

ATTACHMENT 4

RESPONSIVENESS SUMMARY IRP SITES 1, 2, AND 3

FINAL-DOCUMENT REVIEW COMMENTS - RESPONSE SUMMARY

ADEQ COMMENTS ON THE DRAFT FINAL FIRST FIVE-YEAR REVIEW OF THE RECORD OF DECISION FOR SOIL CLEANUP OF

IRPSITES 1,2,AND3 AIR FORCE BASE 44, TUCSON, ARIZONA

DOCUMENT SUMMARY

The document reviewed was the Draft Final First Five -Year Review ofthe Record of Decision (ROD) for Soil Cleanup of Sites 1, 2, 3, 4, 5, and 6, dated Febmary 2003 and associated technical memorandum. The air modeling technical memorandum was rendered moot by the addition of a secondary granular-activated carbon (GAC) unit to all the SVE/DPE systems. Therefore, comments on the technical memorandum will not be explicitly addressed. Also, the initial document format, addressing all six sites in one document, was changed in later comnients, so there are now two documents: Final Firsl Five-Year Review of the Record of Decision for Soil Cleanup of IRP Sites 1, 2, and 3 and Final First Five- Year Review ofthe Record of Decision for Soil Cleanup of IRP Sites 4, 5, and 6. As a result, this table includes all review comments related to both the Sites 1, 2, and 3, and the 4, 5, and 6 five-year reviews.

Item

1

2

3

Page

F-2, Line 8

1, Line 27

6, Line 36

Section

Summary Form

1.0 Introduction

ADEQ REVIEW COMMENTS

Arizona 's Soil Remediation Standards Rule allows for remediation of soils to pre-calculated residential or non-residential standards (SRLs), to site background concentrations, or to a site-specific risk-based standard. However, because the May 2000 ESD specifically states that soils will be cleaned to Arizona SRLs, an exception for using a risk-based standard for TPH at Site 2 will likely be needed.

The Burr-Brown Corporation project area is now the Texas Instruments project area. Please change the name to Texas Instruments. Typographical error. Please change CAC to GAC

Response

The text was revised to read : "TPH is found in concentrations above the ADEQ SRLs for nonresidential land use specified as the cleanup level in the May 2000 Explanation of Significant Difference (ESD). Because of depth to groundwater (e.g., 150 feet), data showing no impacts to groundwater from the TPH, and the lack of completed exposure pathways, the Air Force asked ADEQ to evaluate potential risk from TPH at Site 2. In March 2003, ADEQ found that residual risk from TPH does not pose an unacceptable risk to human health for residential or non-residential uses. Thus, the TPH will be left in place." |

This sentence has been omitted as unnecessary.

The text has been corrected

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Finat Attachment 4 - Document Review Comments Response Summaiy ADEQ Comments on the Draft Final

First Five- Year Review of The Record Of Decision for Soil Cleanup of

I R P Sites 1.2 and, 3 Air Force Base 44, Tucson, Arizona

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6 Site Inspection

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Perhaps it should be added that armed guards are stationed al the entrances to AFP-44. There may be other security features (security patrols?) to control site access that could also be added to this section if they are not a security secret.

Please clarify that the air emissions modeled were post-GAC emissions

A Declaration of Environmental Use Restriction (DEUR) for AFP-44 soils .should be applied as soon as the soil remedy is complete and contamination above state SRLs is left in place - not "upon sale or transfer ofthe property. " Normally, a DEUR would be a condition of approval by ADEQ for any site soil closure request where contamination above residential SRLs is left in place.

Response

The text as been revised to read: "The AFP 44 perimeter fence controls access to the sites. Armed guards are stationed at the entrances to AFP 44 and regular security patrols are performed. There is no other site-specific security required by the final ROD. There are no access restrictions or physical controls such as caps or signs in place as part ofthe final remedy for these sites." The text was clarified. These emissions have been eliminated through the use ofa secondary GAC vessel. According to the US Air Force (2000), the following quote applies: ".. .As long as the federal government owns AFP 44, the property will be used for non-residential purposes. The A ir Force will place a deed restriction upon AFP 44 when the property is sold or transferred per General Services Administration (GSA) direction that no federal agency shall place deed restrictions upon U.S. government owned property until the time of sale or transjer" (USAF 2000). Therefore, this comment is not applicable.

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Final Attachment 4 - Documeni Review Comments Response Summaiy ADEQ Comments on the Draft Final

First Five-Year Review of The Record Of Decision for Soil Cleanup of

IRP Sites I, 2 and 3 .Air Force Base 44, Tucson, Arizona

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l.O Introduction

6.2


Protectiveness Slatemeni, first sentence. Please revise to, "All soil (unsaturatedzone) contamination at the sites is either currently being addressed or has already been addressed... " As described in EPA 's Five- Year Review Guidance, "when your review only addresses a portion ofa site, the reporl should provide a summary ofthe status ofthe other operable units (OUs)... " The summaries of OUs 14 andi 7 contained in the previous draft should be incorporated in the final report.

Since the community was not briefed on the progress and preliminary findings of the five-year review at the March 19, 2003 UCAB meeting, this statement should be revised to delete this reference.

Response

The text has been changed to read: "All soil (unsaturated zone) contamination at the sites is either currently being addressed or has already been addressed."

The text has been revised as follows: "There are two groundwater IRP sites at AFP 44. These are IRP Site 14 -Shallow Groundwater Zone (AFRIMS Site OTO 13) and Sitei7 -Regional Groundwater (AFRIMS Site OTO 12). The non-time critical removal action at IRP Site 14 (pump and treat with dual-phase extraction) is ongoing. Similarly, operation of the groundwater pump and treat system at IRP Site 17 continues." This reference was omitted in the final report.

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Final Allachmenl 4 - Document Review Comments Response Summary ADEQ Comments on the Draft Final

First Five-Year Review of The Record Of Decision for Soil Cleanup of.

IRP Sites 1,2 and, 3 Air Force Base 44, Tucson, Arizona

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7.0 Technical Assessment


Answer A, first sentence. The .summary ofthe interviews provided in section 6.6 does not mention that the community members indicated that the remedy is functioning as intended by the RODs for Sites 1-6. Ifthis was a specific question posted in the interviews, please include in section 6.6. Olherwise, this sentence should be revised and the mention of interviews should be deleted.

Please revise lo, "Cleanup levels were, or will be in the future, attained at each ofthe sites reviewed (i.e. AFP 44 Sites 1-6).

Response

The following sentence was inserted in the 5-year review report for Sites 1, 2 and 3, Section 6.6 Interviews: "IRP project review meetings are held on a bimonthly basis for Sites 1, 2, and 3. In addition, community meetings (the UCAB) are held on a bimonthly basis. Interviews with program managers, regulatory reps, local officials, and members of the community took place at these scheduled meetings. Therefore, an interview tailored to evaluate the effectiveness ofthe remedy and the status of IRP Sites 4, 5, and 6 was deemed unnecessary." A similar sentence was inserted in the 5-year review report for Sites 4, 5, and 6. The text in the Sites 1, 2, and 3 Five-year ROD review has been revised to read : "Cleanup levels have been attained at IRP Sites 1 and 2 and will be attained in the future at IRP Site 3. Remedial actions have been completed at IRP Site 1 and Site 2."

The text in the Sites 4, 5, and 6 Five-year ROD review has been changed to read: "Cleanup levels have been attained and remedial action is complete at IRP Site 4 and IRP Site 6 as well as metals-contaminated soils associated with the former sludge drj/ing beds at Site 5."

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Finai Attachment 4 - Document Review Comments Response Summaiy ADEQ Coinments on the Draft Final

First Five-Year Review of The Record Of Decision for Soil Cleanup of

IRP Sites 1, 2 and. 3 Air Force Base 44, Tucson, Arizona

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11.0 Next Review

Attachment 1

Attachment 1


Based on EPA 's Five-year Review Guidance, the next five-year review is required five years from the date of EPA 's concurrence signature on this review.

Revising the model assumptions to reflect 5 years ofexpo.sure duralion does not seem appropriate in this case since the SVE .system has been in operation since 1996 and ihere is no estimated completion dale to achieve site closure. Revising the model assumptions to reflect 5 years ofexposure duration does not seem appropriate in this case since the SVE system has been in operation since 1996 and there is no estimate completion date to achieve site closure.

Response

This comment has been addressed in the Sites 1, 2, and 3 Five-year ROD review as follows: "The next five-year review for AFP 44, IRP Sites 1, 2, and 3 is required five years from the date of submittal ofthe final five-year review." A similar revision was made to the Sites 4, 5, and 6 Five-Year Review.

Not Applicable - Modeling has been rendered moot because a secondary GAC vessel was added to all SVE/DPE systems, thereby eliminating emissions.


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Final Allachmenl 4 - Documeni Review Commenls Response Summaiy ADEQ Commenls on the Draft Final

First Five- Year Review of The Record Of Decision for Soil Cleanup of

IRP Sites I, 2 and 3 Air Force Base 44, Tucson, Arizona

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Attachment 1. Remedial

Implementation

Table 5-1

Section 3-2

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As described [in] the previous draft Five-Year Review, the text needs to explain that the Air Force perforined a non-time critical removal action at the sile implementing this remedy, which began in February 1996.

The expansion ofthe DPE .system in December 2000 (as referenced on page 1-25) should also be included in this table. The description ofthe remedial implementation should also include the system expansion performed in 2002 (as indicated in Table 5-1)

Response

This comment has been addressed and reads as follows for the IRP Sites 1, 2, and 3 Five-year review: "The United States Air Force subinitted a work plan for a non-time critical removal action at IRP Sites 1, 2, and 3, an Engineering Evaluation/Cost Analysis (EE/CA), and Proposed Plan to USEPA and ADEQ in September 1995. Implementation of the non-time critical removal action to eliminate continuing sources of groundwater containination and/or to address potential risks to human health and the environment at IRP Sites 1, 2, and 3 began in January 1996. The Air Force signed the ROD for IRP Sites 1,2, and 3 on May 19, 1998." The comment has been addressed in the same fashion for the Sites 4, 5, and 6 Five-year review.

The chronology of events for Site 5 has been clarified throughout.

No significant systeni expansion occurred at Site 5 in 2002.

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Final Attachment 4 - Document Review Comments Response Summaiy ADEQ Comments on the Draft Final

First Five- Year Review of The Record Of Decision for Soil Cleanup qf

IRP Sites 1, 2 and, 3 Air Force Base 44, Tucson, Arizona

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Attachment I, Section 3.2


Revising the model assumptions to reflect 5 years ofexposure duralion does not seem appropriate in this case since the SVE system has already been in operation since 1995 and is anticipated to operated through 2005. The screening emission concentralions should be compared to the average SVE off-gas concentrations measured during the lifetime operation ofthe .system rather than the concentrations measured over the past year. The RPO recommendation to add an additional GAC canister in a lead-lag arrangement should be seriously reconsidered to ensure lhat screening emission ratesfor the DPE .system are met.

This section indicates that 28,518 tons of soil was removed from Site 6 East and Site 6 West while section 6.1 indicates that 38,192 tons of soil was removed from these areas. Please ensure that these two sections are consistent.

Response



This comment has been addressed and the following sentence has been added to the text: "...Therefore, the RPO recommended an additional GAC canister be added to the Site 5 system in a lead-lag arrangement." The secondary GAC unit was added in 2003.

This comment has been addressed and the correct tonnage of 28,518 was stated for both Sections 3.2 and 6.1

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