## 8 i 5 0 File: 1 7G D.P .



# ELLSW O RTH AFB S O UTH DAK O TA

I I 

# ADM INISTRATIVE RE C ORD CO VE R SHE E T

AR File Number _ /

II I 1File: 

## :: - 81 5 1 _t5



# F in al Reco r d o f D ecisio n for R emedia l A ctio n a t O pe r able Un it 1 E llsworth Air Force Base, South Dakota

United States Air Force Air Combat C o mmand Ellsw o rth Air F o rce Base
April 1996

AF Project No . : F X

BM 94- 7 002

## -., 815 2 Final Record of Decision Operable Unit 1

__ , EIls w orthAir Force Base, South Dakota TABL E OF CONTENTS C hapter Page 1 . 0 DECLA RA T ION FO R T HE REC ORD OF DECISION ................................................................. 1- 1 1 . I SIT E NA M E A N D LOCA T IO N ............................................................................................ 1 -1 1 ,2 STATEMEN T OF BASIS AN D PU R POSE .......................................................................... I - 1 1 . 3 AS S ESSME N T OF T HE SITE .............................................................................................. 1 -1 1 , 4 DESC R IP TI ON OF SELECTED R EMEDY .......................................................................... I-I 1.5 STA T U T OR Y DET E RMINAT I O N ..................................................................................... 1- 2 1.6 SIGNATURE AND AGENC Y CON C URREN C E O N THE RE MED Y ................................. 1- 2 2. 0 DE CI SION S UMM A RY .................................... :::............................................. -............................ 2 - 1 2.1 SITE N A M E AN D LOCATION ............................................................................................ 2 -I 2.2 OPE RABL E UNI T 1 (OU-1) DESC RI P T ION / HIS T O RY AN D R EGULA T O RY O V E R S I GH T AC T IV I T I ES ....................................................................... 2 -1 2.2.1 D escripti on / History ................................................................................................. 2-1 2.2.2 Regulatory Oversight Activities ............................................................................... 2-2 2.3 HIGHLIGHTS OF COMMUNITY P A RTICIPATION .......................................................... 2-3 2.4 SCOPE AND ROLE OF RESPONSE ACTION .................................................................... 2-4 2.5 SITE C HARACTERISTICS .................................................................................................. 2 - 5 2.5.1 Soils ....................................................................................................................... 2-5 2.5.2 Sediment ....................................... 2 -6 2.5.3 Ground Water ......................................................................................................... 2-6 2 .5.4 Surface Water ................................................................................................. i....... 2-7 2.6 SITE RISK SUMMARY ....................................................................................................... 2-7 2.7 DESCRIPTION OF ALTERNATIVES ................................................................................. 2-9 2.8 SUMMARY OF COMPARATIVE ANALYSIS OF ALTERNATIVES ............................... 2-10 2.8.1 Overall Protection of Human Health and the Environment ...................................... 2-11 2.8. 2 Compliance with AR A Rs ...................................................................................... 2-11 2.8.3 Long-Term Effectiveness and Permanence ............................................................. 2-14 2.8.4 Reduction of Toxicity, Mobility, and Volume Through Treatment ......................... 2-14 2.8.5 Short-Term Effectiveness ...................................................................................... 2-15 2 .8.6 Implementability .................................................................................................. 2-15 2.8.7 Cost ...................................................................................................................... 2-15 2.8.8 State Acceptance ................................................................................................... 2-17 2.8.9 Community Acceptance ........... ; .2-17 2.9 SELECTED ALTERNATIVE ............................................................................................. 2-17 2.10 ST A TUTORY DETERMINATIONS .................................................................................. 2-20 2.10. I Protection of Human Health and the Environment .................................................. 2-20 2.1 0 .2 Compliance with AR AR s ...................................................................................... 2-21 2.10.3 Cost Effectiveness ................................................................................................. 2-21 2.10.4 Utilization of Permanent Solutions and Alternative Treatment Technologies to the Extent Possible ...................................................................... 2-21 2.10.5 Preference for Treatment as a Principal Element .................................................... 2-21 2.11 DOCUMENT A TION OF SIGNIFICANT CHANGES ........................................................ 2-21 3.0 LIST O F A CRONYMS A ND AB BREVI A TIONS ......................................................................... 3-I

F'_ PROJ

_ 603 7 884 L_" Sl OU1
- ROD_'T rNAL

_ OUIROD . FNL 

### i May 2 , 1996' 815 " _ 3 F i nalRecordofDecisionOperableUnitl

. Ellsworth A ir Force Base, South Dakota f
A PPENDICES A ppen d i x A Figures Appendix B Respo n sive n ess Summary
L IS T O F FIG U RES F igure 2 - 1 Area Locati on Map Figure 2 - 2 Site Map Figure 2 - 3 Operable Uni t 1 Figure 2-4 Area of Attainment for Source Area Soils Figure 2 -5 Area of A ttai n me n t for Grou n d Water LIS T O F T ABLE S Table 2-1 OU-1 Cleanup Goals - Ground Water Table 2-2 OU-1 Cleanup Goals - Soils Table 2-3 Evaluation of Federal and State ARARs That May Apply to OU-1 , Ellsworth AFB, South Dakota

ii F:'_PROJ

_ 6037884W Sq OUI
- RODW1NALI OUIROD . FNL April 1996

## 815 4 Final Record o/Decision Operable Uni .' tl

Ellsworth Air Force Base, South Dakota 1.0 DECLARATION FOR T H E RECORD OF DECISION (ROD) 1.1 SITE NA M E AND LOCATION

• Operable Unit 1 (OU-1), Abandoned Fire Protection Training Area, Ellsworth Air Force Base (EAFB), National Priorities List Site. • Meade and Pennington Counties, South Dakota 1.2 STAT E ME N T O F B A SIS A N D PURPOSE T h i s de c ision docum e nt de s cri b e s E A F B ' s sel ec ted r e m e d ia l a c tion fo r Operable Unit 1 ( OU-1 ), in a cc o r dance w ith th e Comp r e h en s ive Envi r onmental R espon s e, Com p en s ation, and Liab ility Ac t of 19 80 ( C ER CLA) , a s amended b y the Su p e rfun d Amend m ents and R eauth o ri z a tio n A ct of 19 8 6 (SA RA ) , and th e Nati o nal O i l and Hazar dous Subs tan c e s Polluti o n Con tingen c y Plan (NCP ). T hi s decisi o n is b as e d on th e co n tents of th e Ad mini s trative R eco rd fo r OU-1, E A FB. Th e United State s E nvi r onmental Pr ote ction Agen c y (E PA ) and th e South D akota D ep artm ent of E nvi r onment and Na tural Re sou rc e s (SD D EN R) con c u r w i th th e s ele ct e d r emedial a c tion
. 1.3 ASSESSMENT OF T H E SITE Actual o r th reatened r elea s e s of h a z ar dous subst ances f r o m OU-1, if not ad dres sed b y im p lementing th e r espon s e a cti on s elec t e d i n th i s R eco r d of De c i s ion ( R O D), m ay pr e sen t an i mminent an d s ub stanti al endange rment to p ub li c h ealth , w elfar e, and th e envi r onment 1.4 DESCRIP TION O F SELECTED RE MEDY T w elve contaminated ar ea s , delinea t ed as o p e r abl e un i ts (OU s) f o r i n vesti g ative pu rpose s , h ave b een identi fi ed at E AF B. T his R OD is fo r a r emedial a c tion at OU-1
. Th e s ele c ted alte rnative, s ou rce ar ea so il and gr oun d - w ate r tr eatment, in c lude s th e f o l low i ng ma j o r c o mp o ne nt s:

• Continued ope r ati o n of th e inte rim r emedial a c ti on ( I RA ) wh i ch c on s i s ted o f c o ntaminated gr ound- w ate r remova l , s oil vapo r e x tr action ( S V E ) , and tr eatm en t ;

• I n sta l lati o n of additional S V E w ell s w ith i n th e h i s to ri cal b um- p i t area to b e ad d ed to th e e x i s ting I RA SVE s y st em ; • R emo v a l of contamina t ed g round w ate r using ad d itional gro und- w ater w ells and c ollection tren ch es to b e add ed to th e I RA ground- w ate r r e c ove ry syst em ; • Tr eatment of gr ound w a t e r at th e e x i s ting I RA tr eatment plant ; • I nstitutional c ontr ols fo r th e ar ea ; 1-1 F .'L °RO .ArO37884 h_l OU]
- ROD h WINALI OUIROD . FNL April 1996

## " 815 5 Final Record o/Decisio n Operable Unit 1

. . .... E @ wot'tk Air Force Base, South Dakota • Long-term m o nitoring; and, • Long-term operation and maintenance of equipment. 1.5 STATUTORY DETERMINATION The selected remedy is pr o tective of human health and the environment, complies with Federal and the State of South Dakota requirements that are legally applicable or relevant and appropriate to the remedial action, and is cost-effective. This remedy utilizes permanent solutions and alternative treatment (or resource recovery) technologies, to the maximum extent practicable for OU-1. A review will be conducted no less often than every five years after signing of the ROD to ensure t hat the remedy con t inues to provide adequate pro tection of human health and the environment. 1 .6 S I GN A TURE AN D AG E N CY CO N C U RRE N C E ON T H E R E M

EDY

BRETT M. DULA Dat e L ie

_ en a n t Ge n e ral, U S AF • Vi Commander

A_i K W MCGRAW ng Regional Administrator kI_ E ironmental Protection Agency Region 8
NETTIE H. lvI'_ERS, Se_lary Date Department of Environ n ie_ and Natural ResourCeS State of South Dakota

FIPROJ

_ 6037884 tFSl OUI
- ROD tFLV: 4LI OUIROD . F, ' _Z 1-2 April I9968 1 5 _ B Final Record of Decision Operable Unit 1 Etls wo rth A i r Force Base + South Dakota • Long-teJm monit o ring; and, • Long-term operation and maintenance of equipment. 1 .5 STATUTORY DETERMINA T ION The selected remedy is protective of human health and the environment , c o mplies with Federal and the State of South Dakota requirements that are legally applicable or relevant and appropriate to the remedial action, and is cost-effective. This remedy utilizes permanent solutions and alterna t ive treatment (or resource recovery) technologies, t o the maximum extent practicable for OU-1. A review will be conducted no less often than every five years aft er signing of the R OD to ensure that the remedy continues to provide adequate protection of human health and the environment. 1 .6 S I GNATURE AND AGE N CY CO N CURREN CE ON T I l E RE MEDY

BRE T T M. DULA Date Lieutenant General, USAF Vice Commander

JA C K W. MCGRAW Date Acting Regional Administrat o r US Envir o nmental Pro t ec tion Agency Reg i on 8
NETTIE H. MYERS, Secre t ary Date D epartment of Environment and Na t ural Resources State of South Dakota

1 '2 F:

_PRO

_ 6037884 hts ' S

_ OUI - RODV ' INALI OUIROD . FNL April 1996

## 81 5 7
: __ Final Record of Decision Operable Unit ' l Ellsworth Ai r Force Base, South Dakota 2.0 DECISION SUMMARY 2.1 SITE NAME AND LOCATION EAFB is a U.S. Air Force Air Combat Command (ACC) installation locat e d 12 miles east of Rapid City, South Dakota , and adjacent to the small community of Box Eider (Figure 2-1). EAFB covers approximately 4 , 858 acres within Meade and Pennington counties and includes runways and airfield operations, industrial areas, and housing and recreational facilities (Figure 2- 2). Open land, containing a few private r e sidences, lies adjacent to EAFB on the north, south, and west, while residential and commercial areas lie to the east of the Base. 2.2 OPERABLE UNIT 1 ( OU-I) DESCRIPTI O N / HISTORY AND REGULATORY OVERSIGHT ACTIVITIES 2.2.1 Description/H istor y Ells w o rth A i r Fo r ce Ba s e ( EAFB ) w a s offic ia l ly a c tiv ated in J uly 194 2 as th e R ap id City A rmy Air B ase, a tr ain i ng f aci li ty for B-17 b omb e r cr e ws. It b e c ame a perma n ent f a c i li ty in 19 48 w i th the 28 th Str ate g i c R e con nai ss an ce Wing a s it s h o st un i t . His t o ric a l ly, E A FB h as b een the he adq u arte r s of ope r ation s fo r a variety of aircr aft , a s w ell a s th e T ita n I Inter co ntin e ntal Ba l l is ti c M is si l e , and the M inutema n I and M inute m an I I m iss ile s y s tem s. T he Ai r F o r ce h a s u s e d E AF B fo r s up p o rt , tr ai ni ng , maintenance, and /

o r te s tin g fa c ilities
. Pres ently, the 2 8 th Bomb ar dme n t Wing ( B- 1 B bo mbers) i s th e h o st u ni t of E AFB
. OU-1 c o nsi s ts of th e fo rm er Fire Pr ote c tion T r ai n i n g A r ea (FPTA) , Pond 001 , and a porti o n of th e d r ai n a g e c h a nn el which lea d s in to Po n d 00 1. Th e f orm e r FPTA i s app r o x i m a t e l y te n a cr e s in s i ze and is located i n th e so uthwes t ern s e g ment o f E A F B (F i g u r e 2 -3 ). T he FPTA w a s o p e r ated b y the EA F B Fire De p artm ent at this location fr om 19 4 2 t o 1990. The l oc ation of th e b urn ar ea w ithi n th e fo rme r FPTA h a s ch anged s e v eral ti me s ov er th e years. Ae rial ph otogr aphs of EA F B d at e d 2 8 May 1 952, 8 O c to b e r 195 4, 25 Aug us t 1 962 a n d 1 9 J une 1 968 sh o w nume r o us ar ea s of st a in i n g p r esumed to be a re s u l t of fire tra ining a c tivi tie s withi n th e for m e r FPTA
. T h e t ra i ni ng exerci s e s c o nd uc t ed at the F PT A invo l ved si mulation of ai rcr aft fir e s and s p i l ls. Var i ous ty p es of f u el s , o i ls , and solv e nt s w e r e di spers ed wi th in the b u rn- p i t ar ea a n d subs equently ignite d and the n e x tinguis h ed . T h e to pograp h y at OU-1 is c h ara c t eri z ed b y a lo c al t opogr ap hic high i n the ar ea w h e r e fi r e tr ai nin g w a s condu ct ed, wh ic h i s b ounde d on the so uthw est and s ou th east b y conve r ging dr a i nage channels. P ond 001 was included in OU - 1 to determine if it c o ntained c o ntaminants which originated at the former FPTA. A shallow aquifer has been identified at depths of 10 feet to 50 feet beneath the ground surface. This ground water is classified as having a beneficial use as a drinking water supply suitable for human consumpti o n (ARSD Chapter 74: 0 3:15 , Groundwater Quality Standards). The shallow aquifer may also discharge to the surface. 2-1 F'lPROJ

_ 6037884 b_' S

_ OUt
- ROD h_7 2VALI OUlROD . FNL April 1996" ". , . , 815 _ 8 Final Record of Decision Operable Unit 1 Ellsworth Air Force Base , South Dakota Deeper bedrock aquifers also exist beneath EAFB, These deeper aq u ifers are separated from the shallow aquifer by 800 feet of low-permeability clays and silts. In the past, EAFB utilized these deeper aquifers for its water supply. Presently, EAFB obtains its potable water from the Rapid City Municipal Distribution System. 2 . 2.2 Regula t ory Over s ig h t A ctivities Env i r o nmental i nvestigatio n acti v i ties at EAFB were initi ated b y the Air Force i n 1985 thr o ugh an Installation Restoration Program (IRP) Phase I Installati o n Assessment / Rec o rds Search and Phase II, Confirmation /

Quan tification. The Phase I study, dated September, 1985, identified a total of 17 locations at EAFB where releases involving hazardous substances potentially occurred. In Phase II of the IRP investigation, field activities included soil vapor surveys, geophysical surveys, surface and subsurface soil sampling, ground-water sampling, gr o und-water hydrologic testing, and ecological investigations. On August 30, 1990 (55 Federal Register 35509), EAFB was listed on the U.S. EPA's National Priorities List (NPL). A Federal Facilities Agreement (FFA) was signed in January 1992 by the Air Force, EPA, and the State of South Dakota (State) and went into effect on April 1, 1992. The FFA establishes a procedural framework and schedule for developing, implementing , and monitoring appropriate response ac tions for EAFB in accordance with the Comprehensive Environmental Response, Compensation, and Liability Act of 1980 (CERCLA), as amended by the S u perfund Amendments a nd Reauthorization Act of 1986 (SARA), and the National Oil and Hazardous Substances Pollution Contingency Plan (NCP). It also states the oversight procedures for EPA and the State to ensure Air Force compliance with the specific requirements. The FFAidentified 11 site-specific operable units (OUs) and a Base-wide ground-water OU. The Basewide ground-water OU is primarily used to address contaminated ground water that was not addressed during the investigation of a site-specific OU. Listing on the NPL and execution of the FFA required the U.S. Air Force to perform a remedial investigation/feasibility study (RI F FS) to investigate the 12 OUs. In 1993 and 1994 , an extensive RI field program was conducted to characterize conditions at OU-1. The program included drilling and sampling ofboreholes , installation of ground-water monitoring wells , ground-water sampling , geotechnical analysis of soil samples, ecological evaluation, assessment of human health risks, and review and compil a tion of previous IRP investigations. Collection and laboratory analysis of soil, ground-water, surface-water, and sediment samples were included in the RI field program. A ROD for an interim remedial action (IRA) for O U -1 was signed on 16 May 1995. The objectives of the IRA were (1) to remediate the deeper soils within the bum-pit area and (2) to remediate ground-water contamination immediately downgradient from the burn-pit area. The remediation of the deeper soils within the bum-pit area consists of a soil vapor extraction system and subsequent treatment by thermal oxidation. The remediation of contaminated ground water immediately downgradient of the burn-pit area consists of removal of contaminated ground-water using wells and an existing ground-water recovery trench. Treatment of the contaminated ground water consists of filtration, air stripping, and activated-carbon adsorption. The treatment system 2-2 F: lPROJ 1 6037884 1 F A q OU1
- ROD

_F1NALI OUIROD . FNL April 1996

## 815 " 9 Final Record of Decision Operable Unit 1

Ellsworth Air Force Base , South Dakota was constructed as part of the IRA. 2.3 I_IGltLI GItTS OF COMMUNITY PARTICIPATION Community relations activities that have taken place at EAFB to date include: • FFA process. After preparation of the FFA by the USAF, EPA, and SDDENR, the document was published for comment. The FFA became effective April 1, 1992. • Adminis t rative Record. An Administrative Record for information was established in Building 8203 at EAFB. The Administrative Record contains information used to support USAF decisions. All the documents in the Administrative Record are available to the public.

• Informa t ion repositories. An Administrative Record outline is located at the Rapid City Library (public repository). • Community Relations Plan (CLIP). The CRP was prepared and has been accepted by EPA and the State of South Dakota and is currently being implemented. An update to this plan will be prepared in 1996.

• Res toration Advisory Board (RAB). The RAB has been formed to facilitate public input in the cleanup and meets quarterly. In addition to USAF, EPA, and South Dakota oversight personnel, the RAB includes community leaders and local representatives from the surrounding area. • Mailing list. A mailing list & all interested parties in the community is maintained by EAFB and updated regularly. • Pac t shee t . A fact sheet describing the status of the IRP at EAFB was distributed to the mailing list addressees in 1992. • Open house. An informational meeting on the status of the IRP and other environmental efforts at EAFB was held on May 6, 1993. An open house was held November 16 , 1995 in conjunction with the Restoration Advisory Board meeting. Information on the status of environmental efforts at EAFB was provided at the open house. • Newspaper articles. Articles have been written for the Base newspaper regarding IRP activity. • Proposed Plan. The proposed plan on this action was distributed to the mailing list addressees for their comments. A public comment period was held from September 18, 1995 to October 18 , 1995, and a public meeting was held on September 26, 19 9 5. At this meeting, representatives from EAFB answered 2-3 _' q :_ ROJ

_ 6037884_" S

_ OU1
- ROD l FINALI OUIROD .F NL April 1996

## 815 I0 FinalRecor do fDecis i onO p erableUnit1

. Ellsworth Air Force Base, South Dakota questions about the remedial a c tion. A response t o the comments re c eived during this period is included in the Responsiveness Summary, which is part of this Record of Decision (ROD). This ROD is based on the contents of the Administrative Record for OU-I, in accordance with the CERCLA, as amended by SARA, and the NCP. The RI F FS reports and the Proposed Plan for OU-1 provide information about OU-I and the selected remedy. These documents are available at the Information Repositories at EAFB and the Rapid City Public Library. 2.4 SCO P E AND ROLE OF RES P ONSE ACTION The FFA identified 11 site-spe c ifi c OUs and a Base-wide g ro u nd-water OU. Th e 12 operable units are identified as follows: O U-I Fire Pro l ec ti o n Training Area OU - 2 Landfills Nos 1 a nd 6 OU-3 Landfill No. 2 OU-4 Landfill No. 3 OU-5 Landfill No. 4 OU-6 Landfill No. 5 OU-7 Weapons Storage Area O U -8 Explosive Ordnance Dispos a l A r e a (Pramitol S pi ll) OU-9 Old Auto Hobby Shop Area OU- 10 North Hangar Complex OU-1 1 Base-wide Ground Water OU-12 Hardfill No. 1 This ROD documents the selected remedial action (RA ) a t OU-I and i s the fourth ROD for EAFB. The remedial action objectives (RAOs) are: (1) the cleanup of ground water to regulatory levels and, for contaminants where regulatory levels are not available, to levels considered safe for public drinking water, and (2) the cleanup of source area soils to levels that would not pose a threat o f co n taminating ground water. The development of alternatives was conducted under EPA's Presumptive Remedies Approach [Presumptive Remedies ." Policy and Procedures (OSWER Directive 9355 . 0
- 47FS); Presu m ptive Remedies ." Site Characterization and Technology Select i on for CERCLA Sites with Volatile Organic Co m pounds in Soils (OSWER Directive 9355.0-48FS) ] . Using this approach, selecting an alternative for remediation is streamlined by using preferred technologies based on historical patterns of remedy selection and EPA's scientific and engineering evaluation of performance data on technology implementation. T

he presumptive remedy stipulates s o il vapor extraction (SVE) as the p rimary remedy for soils that are contaminated with volatile organic compounds (VOCs). In addition, thermal desorption is being retained as a secondary source area soil treatment option. The response action, sourcearea s oil and gr o u n d-water treatment, c ombi n es the presumptive remedies for soil with gr o undwater extraction and treatment to reduce risk associated with the ingestion exposure pathway.
2-4 F:

_PRO .A6037884 h_S % OUI
- ROD [ Fl " NALl OUlROD . FNL April 1996

## 8 1 5 I! Final Record of Decision Operable Unit 1

Ells worth Air Force Base, South Dakota The area over which remediation goals would be achieved is defined as the area of attainment, and is based on the RAOs . The area of attainment would include areas within OU-1 which present an unacceptable risk to human health or the environment. 2.5 S I TE CHARA C TER I S T I CS This section describes the presence and distribution of contaminants at OU-1 as a result of past activities. 2.5. 1 S oi ls O r g anic Contaminan ts Organi c c ompound s reported in s oi l samples fr o m OU-1 includ e v o latile organic compounds (VOCs), jet fuel, semivolatile organic compounds (SVOCs), pesticides , and dioxins / furans. Total petroleum hydrocarbon (TPH) concentrations, analyzed as jet fuel, above the State of South Dakota action level (500 ppm) were reported in 4 surface-soil samples and 11 capillary fringe soil samples located in and adjacent to the burn pit. Soil which has been impacted by past activities at OU-1 extends from the surface to the capillary fringe beneath the former FPTA, and within the capillary fringe from the former FPTA to approximately 800 feet to the south. In general, the most prevalent organic contaminant in the soil is jet fuel. The State of South Dakota regulations for petroleum-contaminated soils have been recently revised and effective December 18, 1995; new risk-based criteria are used to determine if petroleum-contaminated soil requires removal or treatment. The new regulations establish a three-tiered approach in determining what action will be taken at petroleum release sites (ARSD Chapter 74:03:13). The regulations establish Tier 1 action levels for five petroleum related components (benzene, ethylbenzene, toluene, xylene, and naphthalene) and TPH. Two of the five chemicals (benzene and ethylbenzene) for which soil action levels have been established by the State were detected in the soil above their respective action levels in three different borings in the vicinity of the burn pit.

Concentrations of TPH (as jet fuel) in the soil were above the 500 ppm Tier 1 action limit in 12 different soil boring locations in and around the bum pit area. Based on this , a Tier II evaluation is required. Because pathways and receptors are present , remediation of jet fuel is required. Also , State guidance concerning the need for installation of monitoring wells at a petroleum release site (Handbook for Investigation and Corrective Action Requirements for Discharges from Storage Tanks, Piping Systems , and Other Releases, SDDENR Ground-Water Quality Program, Version 1.1, December 18 , 1995) indicates that monitoring wells will be required at this site. Inorganic Contaminants In general, the subsurface-soil samples which c o ntained the highest concentrations of inorganic compounds were from the former bum-pit area. The source of the inorganic compounds in OU-1 subsurface-soil samples is believed to be from a combination of bum pit activities and naturally-occurring geologic deposits and soil type. No distinct pattern was observed for the higher concentrations of inorganic compounds in OU-1 surface-soil samples. 2-5 F: i PROJ I 6037884 b_' S

_ OU1
- ROD

_ b' #l

ALk OUIROD . r '- NL April 1996

## 8 1 5 1 2

• - • " t Final Record o f Decision O p erable Unit 1
-. Ellsworth Air Force Base, South Dakota 2,5.2 Sediment O r ga n i c C onta m i n a nts VOCs, SVOCs, and pesticides were reported in sediment samples collected from the drainage channe l both upgradient and downgradient of OU - 1 , from within the d rainage channe l at OU - I, and within Pond 001. Although OU - 1 may have contri b u ted to the con t aminan t s in sedimen t , the presenc e o f these organic compound s in samples collected upstream of OU - 1 indicates that the primary source of contaminants in sed i ments is from ar e as upgradient of O U -1. The highest concentrations o f contaminan t s were in Pond 001 where sedim e nts are like ly to buil d up over time. I t is not poss i ble to disti n g uish the exac t source of con taminan t s in the sediments in the pond. Possible upgradient sources for the organic compounds in sediment samples are the operations ar e as along the taxiway s and flightlines. In o rganic Contaminan t s Many of the inorganic analytes were reported only once in each of the nine sediment samples with t he exception of cy a nide , thallium, a nd mercury . The source & the inorganic analytes is thought to be a combination of surface-water runoff from both outside and within OU-1 as well as naturally-occurring geologic deposits and soil type. 2.5.3 G ro u nd Wat er O rgan i c Contaminants Con taminan t s were found in ground - w a ter samples from both within and downgradient of the former FPTA. The most frequently reported organic contaminant in ground-water samples from OU-1 were VOCs. SVOCs were reported in ground-water samples t o a lesser extent• VOCs and SVOCs in the gr o und water are a result of historical use of fuels , waste oiIs, and s o lvents in the burn-pit area. Seven VOCs, one SVOC, and o ne pesticide were reported at least o nce at concentrations exceeding the Safe Drinking Water Act Maximum Contaminant Level (MCL). I norganic Conta min a nts Thirteen inorganic compounds were detected in ground-water samples at concentrations which were above general background levels• However, due to variations in soil type and geologic deposits , localized high concentra t ions of inorganic compounds in the EAFB area are common. Two compounds , manganese and antimony, we i e reported at least once at concentrations exceeding the MCL. Regional and site-specific background results indicate that these two inorganic compounds naturally occur at levels in ground water that exceed the MC L and their presence is not thought to be a result of historical activi t ies at OU-1. Arsenic was repor ted in four ground-water samples at concentrations of two to six times background from locations within and downgradient of the burn pit. In general, the'remaining inorganic compounds were also detected in samples from locations within, and immediately downgradient of, the burn-pit area. The source of the remaining inorganic compounds is considered to be primarily a result of historical activities at the FPTA, although some compounds may be a result of the natural 2 - 6 F '

lPROJ t 6037884 b_ OUI - ROD

_FlNALl OUIROD.b " NL April 1996

## 815 13 Final Record of Decision Operable Unit 1

Ellsworth A ir Force Base, South Dakota variations in soil type and geologic deposits• 2 . 5.4 Surface Water O r ganic Con t aminant s Th r ee V OCs , one ph thalate, and one polyn uc lear ar oma t i c hyd r ocarb on ( PAH ) we r e r epo rt ed in su rfa c e-wa t e r s a mple s f r o m the d r ainage c hannel and P ond 0 0 1 . The o r g a ni c c omp o und s r epo rte d in s u rf a c e-wate r s amp l e s we r e no t r ep orted in soil or gr ound-wa t e r s ample s from within O U-1 and ar e belie v ed t o be a r e s ult & s u rfa c e s pills out s ide of O U-1. Inorganic Contaminant s O f the ino r gani c c on t aminant s de t ec t ed in s u rfa c e-wate r s ample s , ars eni c , mangane s e and ni ckel ex c eeded Fede r al Ambient Wate r Q uality Crite ria ( FAW QC) and S t ate Wa t e r Q uality St andar d s . The s ou rce o f the ino r gani c analyte s in OU-1 surfa ce - w ate r s ample s i s not kno w n, bu t i s s u s pe c ted t o be f r om the fligh tline ar ea, whi c h i s up s tr eam and out s ide of O U-1. 2.6 SITE RISK SUMMARY Human Health Risks Ri s k A s se s sment Proce ss The a ss e s smen t of hu m an heal th ri sks fo r th i s OU c on s ide r ed the f o l l ow i n g topi cs: •( 1 ) Chemi c als & c once rn ( C OCs) in gr o u nd- wat e r , s u rf a c e wate r, s ediment, and s oil s ample s taken a t O U-1 ; (2) C u rr en t and futu r e land-u s e condition s; ( 3 ) Potential en v i r onmental pa thway s b y which pop u lation s mi g h t be expo s ed ; ( 4 ) Estimated expo s u r e poin t c on c entr a tion s of COCs; ( 5 ) E stimated in t ake l ev el s of the COCs; ( 6) Toxi c i ty of th e COCs; and ( 7 ) Un c e rtain ti es in the a ss e ss men ts of expo s u r e, t oxicity, and gene r al ri sks. N o ncar c inogeni c and c arc inoge nic ri sks we re c a l culated f o r the f ollowing fi ve potential e x po s u r e gr oup s: ( 1 ) C u rr ent EAFB main t enance pe rs onnel mowing gr as s on- s i t e ; 2 -7 F: IPROJ 2 6037884_" S '_ OUI
- ROD

_FINALI OUlROD . FNL April 1996

## -., 815 7 1 4

" FinalRecordofDecision Operable Unit 1 Ellsworth Air Force Base, South Dakota (2) The future child /

adult living on-site who ingests surface Soil; (3) The future adult living on-site who ingests and showers with shallow ground water; (4) Future adolescents who are exposed to surface water and sediment through wading; and, (5) Future adult construction workers who excavate on-site for building residences. A quantitative risk assessment was performed f or the ground water, surface water , soil, sediment , and air. The risk assessment e v al u ated potential effects on human health posed by expos u r e to c ontaminants from OU-1. Car c inogeni c r isks we re estimated as the in cremental probability of an i n dividual dev e lopi n g c ancer ov e r a lifetime as a r e sult o f e xposure to a p o tential canc e r-causi n g chemical. The acceptable risk range expressed as a probability is one cancer incidence in ten thousand people to one cancer incident in a million people. This level of risk is also denoted by 1 x 10-4to 1 x 106. Risks within the acceptable risk range may or may not warrant remedial action depending upon site-specific circumstances. Risks below this range cannot be differentiated from the background occurrence of cancer in human populations. Risks calculated in a risk assessment are excess (i.e., over background) cancer risks due to exposure from contaminants. Noncarcinogenic health risks are evaluated using a hazard index (HI). If the hazard index is less than or equal to one, the contaminant concentration is considered an acceptable level and generally assumes that the human population may be exposed to it during a 30-year period without adverse health effects. R i s k A s s e s s ment Re s ults T he risk a s sessment for OU-I i ndi c ated una cc e p tab le risk in the s h allo w ground w ate r fo r the r esidential e x posu r e sce narios
. T h e chemi c al s which contri b uted th e ma j o rity of the risk in s hal lo w gr ound w at e r we re VOC s. Of the V OC s , b enz ene , 1 , 2 -di chl o r oetha n e , ( 1 ,2 -DCA ) 1 , 1-di ch lo r o e th yl ene (i, 1-DCE ) , 1 , 2-d ich lo r oeth y l en e ( 1 , 2 -DCE ), 1 , 1,1-trich lo r o e th a ne, perch l or oeth yle ne (PCE ) , tri chl oro eth yl e n e ( TCE ) , and vi n yl ch lor i de w ere id e n ti fied a s be ing abov e th eir re s p e c tive MCL s. T he ris k a s se s sment i ndi c ated th at una cc ep t ab l e r i sk e xis t s i n the so il s of the b u rn-pi t ar ea , prim arily f rom the p otential fo r c on t am i nating th e u nd erlying ground w a te r. I n ord e r to p r e ven t futu re c o nta mi nat i on o f the ground w ate r , f ou r V OC s w e re i d e nti fied fo r rem ed i ation in s oil s: be nz e n e , 1, 2 -DCE, PCE , a n d TCE
. T h e s e chemicals w e r e s e le c t e d f o r re me d i atio n o n the b as i s of a contam i nant tr ans p o rt mod e l. Reme d i atio n of je t fu el i n the so il at OU- 1 is also r e qu i r e d b ecaus e c on c en t rations o f jet fue l (and re lated co mp onen t s ) e xc eed Stat e of South Dakot a re g u la tion s. R is k s from e xp o s ure to p es tic id e s and d i o x ins / fu r an s in s u rf a ce and subs u rf a c e s o i ls at OU- I w ere w e ll b e lo w the ac c ep t ab l e range and do no t w ar r a nt re me diati on . T h e risk f r om th e c ontaminants in the sed i ments and s u rf a c e w ate r at OU- 1 is with in the a cc e p tab le r i sk range . Seve r al c om p ounds w e r e dete c ted in s u rf a c e w at er at ab ove th e FAWQC, b ut th e ris k to h uman h ealth fro m th es e c ontam i nants is wi thi n the a cce ptable ris k range . Be c aus e of the r isk b eing wi th in th e a cc eptab le risk range , r em ed i ation of th e se ch emi c als in su rf a c e w ate r 2-8 F ..L oROJ

_ 6037884 h_S

_ OUI - ROD

_FINAL

_ OUIROD . FNL April 1996

## 815 15 Final Reco rd of Decision Operable Unit 1

Ells

_vorth Air Force Base, South D akota and sediment is not warranted. Ri s k Ass es s ment Conclu s ion s R e me diation of the ground w at er is w arr anted b ased on the ri sk to h uman he alth fro m ing es ting and contacting contaminated ground water. Remediation of soil is warranted based on the potential for contaminants in the soil to be transported to the underlying ground water. Actual or threatened releases of hazardous substances from OU-1, if not addressed by implementing the response action selected in this Record & Decision (ROD) , may present an imminent and substantial endangerment to public health, welfare, and the environment. Ecological Risks An ecological ri s k evaluation of OU-1 was based on a combination of data and literature review s , field and laboratory analyses , analyte evaluation and screening, and preliminary risk screening. The pertinent findings are summarized below. A variety of animal species may live, forage, or nest in OU-1 habitats. These species include various types of invertebrates, amphibians, birds, and mammals. Terrestrial vegetation and soil faunal communities do not reveal characteristics that indicate chemical-related impacts. This finding is consistent with the relatively low levels of contaminants in the soil. Because of the altered natural environment at OU-1, rare, threatened, or endangered species are unlikely to utilize the area for more than brief, periodic habitat. Due to the low levels of contaminant concentrations and the identified exposure pathways, the contaminants do not pose an unacceptable risk to these species. In addition, the limited contact these species w o uld have with the OU- 1 area ensures unacceptable risk to a single individual will not occur. Findings of the RI indicate that the contaminants at OU-I are not altering the ecology to unacceptable levels. A Base-wide ecological risk assessment will be conducted as part ofOU-11, and OU-1 will be included in this Base-wide evaluation. 2.7 DE SC R I P T I ON OF ALTERN A TIVE S Presu m ptive Remedies: Site Characterization and Technology Selectio n for CERCLA Sites with Volatile Organic Co m pounds in Soils ( OSWE R D i rec ti v e 9 355, 0-4 8F S ) w a s th e ba si s o f the streamlined feasi b ility study ( F S ). T h is pr esu mp tiv e re medy w a s inc o rp o r at e d int o the re m e dial a c ti on a t OU-1 to d e v e lop th e fo l lo w ing al t e rnative s.
* Alternative I - N o Furth er Actio n • The no further ac tion a lternative represents the baseline condition at OU - 1 and refers to taking no further action at the operable unit. • Al t ernative 2 - Source Area S o il Treatment with Gr o und-water Containment 2-9 F:WRO . Bro37884_rS

_ OUI
- RODWIblAL _O UIROD . FNL April 1996

## : 815 16 - j Final Record of Decision Operable Unit 1 Etlsworth Air Force Base, South Dakota • Continued operation of the interim remedial action (IRA). • Installation and use o f additi o nal SVE wells, gr o und-water wells and /

or collection trenches to c o ntain the existing soil and ground-water contamination. • Soil gas and contaminated ground water would be treated at the IRA treatment plant. The water effluent will either be discharged to a surface water drainage, pumped to the Base waste-water treatment plant , or injected underground. • Long-term maintenance and monitoring. • Institutional controls (access restrictions and deed restrictions).

• Alte rnative 3 - Source Area S o il Treatment and Ground-water Treatment • Same as A lternative 2 with additional ground-water wells and trenches. This alternative is the same as Alternative 2 except that the ground-water removal system would be designed to not only contain the contaminated ground water, but to permanently lower the contaminant concentrations in the ground water to the levels listed in Table 2-1. 2.8 SUMMA R Y OF C OMPARATIVE A NALYS IS O F ALTERNA T IVES The analysis of altematives coupled with the use of the presumptive remedy combine for a narrower range of feasible approaches to address remedial activities at O U -1. The remedial action objectives for OU-1 are as follows: • Achieve the gr o und-water clean-up goals set f o rth in Table 2-1. • Achieve the soil clean - up goals set fo rt h in Table 2 - 2. The area of attainment is defined as the area which will achieve the remedial action objectives after remediation is completed. The areal extent of the source-area soil attainment area for OU-1 is based on reported concentrations of chemicals of concern and is shown in Figure 2-4. The ground-water attainment area was based on MCLs for the reported chemical concentrations at OU-1 and is shown in Figure 2-5. Pursuant to Section 40 CFR 300.430(e)(9)(iii), the remedial action to be implemented should be selected based upon consideration of nine evaluation criteria. These criteria are as follows: 1. Overall protection of human health and environment. 2. Compliance with applicable or relevant and appropriate requirements (ARARs). 3. Long-term effectiveness and permanence. 2- 1 0 F .'_PROJ

_ 6037884_" DOU1
- ROD

_F1NAL

_ OUIROD . FNL April 1996

## 815 17 Final Record o/Decision Operable Unit 1

Ellsworth Air Force Base, South Dakota 4. Reduction of toxicity, mobility, or volume of contamination. 5. Short-term effectiveness. 6. Implementability. 7. Cost. 8. State ac c eptance. 9. Communi ty acceptance. The following sections provide a brief review and comparison of the remedial alternatives according the EPA's evaluation criteria. 2.8.1 O verall Protection of H uman Health and the Environment The assessment of this criterion considers how the alternatives achieve and maintain protection of human health and the environment. Alternative 1 does nothing to reduce risk levels at OU-1. Alternatives 2 and 3 both reduce the risk of source-area soils contaminating the underlying aquifer and address ground-water remediation. Alternatives 2 and 3 would remediate ground water to levels at or below MC L s. However , the primary goal of Alternative 2 is to only contain contaminated ground water. Under Alternative 2, the aquifer may eventually be restored to the levels listed in Table 2-1. It would take approximately 10-15 years longer for the ground water to be remediated to levels listed in Table 2-1 under Alternative 2 as compared to Alternative 3. 2.8.2 C ompliance wi th ARARs Alte rnative s ar e asses s ed unde r th i s crite rion in te rm s of c omplian ce w ith A RA Rs . Appli c ab le r equi r ement s i n c l u de c leanup s tandar d s , standar d s of c ontr ol and oth e r subs tantive envi r o nm ent al p r ote c tion r equi rem ent s , cr i te ria o r li mi t ati o n s p r o mu lgated unde r F ede r al or Sta t e of Sou th Dakota la ws th a t sp e c ifi c ally add r es s a h a z ar dou s s ubstan c e, p ollutant , c ontaminant , re m e dial a c ti o n, lo c ati o n o r oth e r c i rc umstan c es at a CERCLA site
. Relev a nt an d ap pr opriat e r e q ui r ement s addre s s pr o b lem s that do not spe c i fic ally add r e ss a h azar dous s u bs tan c e, p o llutant , o r r emedial a c ti on R ath e r , th e s e r equi r ement s add r e ss p r o b lems o r situ ation s th at ar e similar to th o s e en c ounte r ed at a parti c ular CERCLA site, and th e r efo r e, th e s e r equi r ement s ar e s uited fo r u s e at th e s ite b e c ause of th e s e s imilarities
. ARA Rs ar e gr ou p ed into th ese thr ee c atego rie s:

2-11 _'_PROJ

_ 6037884V'S % OU1 - ROD

_ INALI OU1ROD . FNL April 1996

## 815 I8 Final Record of Decision Ope } able Unit 1

Ells w arth Air Force B ase , So uth Dakota

• C hemi c al - Spe ci fi c ARARs are health or risk-based numerical values or meth o d o l o gies which, when applied t o site-specific c o nditi o ns , result in es t ablishment o f the am o unt o r c o ncentrati o n that may be f o und in, o r discharged to , the environment. • L o cati o n-S p ec i fic AR A Rs restrict the concentrati o n of hazardous substances or the conduct of activities solely because they are in specific locations such as flood plains, wetlands, historic places, and sensitive ecosystems or habitats. • A c tio n-S p e ci fic ARAKs are usually technology or acti vity-based requ i rements or limitations on actions taken with respect to hazardous wastes. T

A BLE 2-1 O U -1 C lean -u p G o al s Ground Water 0ag / L) Analyte Clean - up Goal Basis 1 , 2-Dichl o roethane (1 , 2-DCA) 5.0 MC L 1,1-Dichloroethylene (1,1-DCE) 7.0 MCL 1,2-Dichloroethylene (1,2-DCE) 70.0 MCL 1,1,1-Trichloroethane 5.0 MCL Benz ene 5.0 MCL Tetrachloroethylene (PCE) 5.0 MCL Trichloroethylene (TCE) 5.0 MCL Vin y l Chl o ri d e 2 . 0 MCL TPH 10, 000 State Regulation Ethylbenzene 700 State Regulation Toluene 1,000 State Regulation Xylene 10,000 State Regulation

2- 12 F'LPRO .A6037884 Lr zS

_ OUI. ROD

_FE V

ALI OUIROD , FNL Ap r il 1996

## 815 19 Final Record of Decision Operable Unit "1

Ellsworth Air Force Base , South Dakota TAB LE 2-2 OU-1 Clean-up G oals Soils (_tg / kg) Clean-up Model Analyte Goal Estimates °l Basis 1,2-Dichloroe thylene (1,2-DCE) 41 41 A Ground water pr o tection Benzene 10_2) 2.5 Ground water protection Tetrachloroethylene (laCE) 10 10.5 Ground water protection Trichloroethylene (TCE) 10(27 3.3 Ground water protection JP-4 500, 000 (3_ - State Regulation Toluene 15,000 (3_ - State Regulation Ethylbenzene 10,000 ° ) - State Regulation Xylene 300,000 (3) - State Regulation Naphthalene 25,000 (3_ - State Regulation °)Note: Basedon SUMMERSModel(Summers,1980) (2:'Note:When the modelestimatesare less than standarddetectionlimits,remediatienct e an-upgoalswillbe basedon standard.detectionlimits. O _Note:Stateof SouthDakotaRemediationCriteriafor PetroleumContaminatedSoil,Tier 1 actionlevelsat petroleumreleasesites whichwouldrequirea correctivea c tionplan or T ier 2 analysis (ARSDChapter74:03:33). A summary evaluation of Federal and State ARARs pertinent to this re m edial action is provided in Table 2-3 at the e nd of Sectio n 2.0 and a narrative discussion of compliance with ARARs is provided below for the alternatives considered. Alternative 1 (No Action): Since there are no remedial activities currently being conducted and none are proposed under this alternative, there are no remediation ARARs appli c able. The No Action alternative does not c omply with CERCLA ARARs as a stand-alone action. The ground water at the site would remain contaminated• Alternatives 2 and 3 (Source Area Soil Treatment with Gr o und-water Containment / Treatment): The Safe Drinking Water Act will be complied with by extracting and treating ground water so that contaminant concentrations in the shallow aquifer are below the MCLs. State ground-water quality standards (ARSD Chapter 74:03:15) will also be complied with. However, compliance with MC L s will take approximately 10-15 years longer under Alternative 2 as compared to 2

- 13 F: lPROJ 1 6037884 k_S

_ OUI
- ROD

_FlNALl OUIROD , FNL April 1996- ' 7



## '- ". , - -. , 815 20 Final Record of Decision Operable Unit 1 • Ellswo rth Air Force Base, South Dakota Alternativ e 3. The dis c harge of the treated ground water will comply with State of South Dakota dis c ha rge requirements (ARSD Chapter 74:03:17 for i n dir ec t or dir ec t dis c ha rges into surfa ce waters and ARSD Chapter 74:03:13 for reinjection of discharged water underground). S tate discharge requirements c omply also with Federal requirements of the Clean Water Act (CWA), The proposed SVE system will reduce the concentrations of JP-4 in the soils to levels in compliance with South Dakota Petroleum-Contaminated Soils regulations (ARSD Chapter 74:03:33). Treatment-process residuals such as spent carbon will be disposed of in a manner complying with State and Federal solid waste disposal restrictions (40 CFR 268). Construction of the collection trench will not degrade onsite wetlands and therefore will comply with the Executive Order on Protection of Wetlands and Section 404 of the CWA. Air and water discharges from the IRA treatment facility will comply wi t h South Dako ta Air Pollution Control Regulations (ARSD Chapter 74:26) an d water discharge permit rules and water quality standards as stated above. 2.8.3 Long- T erm Effectiveness and Per m an e nce The assessment of this criterion considered the long-term effectiveness of al ternatives in main taining protection of human health and the environmen t after response action objectives have been met. Alternative 1 d o es not pro v ide l o ng-term effectiveness in achieving the remedial acti o n o bjectives established for this site. No further controls for the OU would be developed under this alternative. For A lternatives 2 a n d 3, residual risk le v els would be low enough that source-area soils would not pose a ri s k to ground water. MCLs would be met for ground water. However, it would take approximately 10-15 years longer for the ground water to be remediated to the MC L s under Alternative 2 as compared to Alternative 3. The ground-water collection system for Alternative 2 would be de s igned to preclude further transport & the ground-water contamination. The groundw a ter collection system for Alternati v e 3 would be designed to also remediate the ground water to the levels listed in Table 2-1. L ong-term monitoring of vapor extraction rates and concentrations would be necessary to maintain proper system operation• 2.8. 4 Reducti on of To x icity, Mobi l ity, a n d Volume T h roug h T reatm ent The asse s smen t of this criterion involves considering the anticipat ed performance of specific treatment technologies an alternative may empl o y. No reduction of potential source area chemicals with respect to toxicity, mobility, or volume would be achieved with Alternative 1. Alternatives 2 and 3 would reduce the volume of VOCs in source-area soils to levels protective of ground-water quality. T he ground-water collection system would reduce the mobility of the ground-water contaminati o n by preventing further downgradient movement. The removal and treatment of contaminants would also reduce the volume of contaminated ground water. The volume ofcontamlnated ground water would be 2- 1 4 F.t

PROJ l dO37884 h_Sl OUI - ROD tFINALI OU1ROD .F NL April 1996

## 815 21 Final Record of Decision Operable Unit 1

Ellsworth Air Force Base, South Dakota reduced faster under Alternative 3 as compared to Alternative 2. 2. 8 .5 S h ort- Te r m Effectivene ss The assessment of this criterion c o nsiders the effectiveness o f al t ernatives in maintaining protection of human health and the environment during the construction of a remedy until response action objectives have been met. Alternative 1 does not provide any short-term effectiveness in reducing potential threats from this site to human health or the environment. Since no construction activities would take place, risk from remedial action would not exist. Adverse environmental impacts due to the construction and implementation of Alternatives 2 and 3 are expected to be minor. Const ru ction would comply with OSHA requirements to help eliminate the risk to construction workers. Community risk is expected to be minimal due to low levels of contaminants in the surface soil and dust control measures would be implemented. 2.8.6 I mp l ementabi l ity T h e ass ess m e nt of th is cri te rion c on si ders th e admin i s tr ativ e a n d t ech ni c a l fe a s i b ili ty o f impleme n ting the alt ernativ e s and th e avai l ab ilityo f n ece s s ary good s and servi ces fo r im p l e mentation of the re s p o n se a c tion There is nothing to implement under Alternative 1. Alternatives 2 and 3 require no special or unique activities and could be implemented using locally available materials and contractors. Any implementability concerns were addressed during the IRA. 2.8.7 Cost The assessment of this criterion c onsiders the capital and operation and maintenance (O&M ) costs associated with each of the alternatives. Alternatives are evaluated for cost in terms of both capital costs and long-term O&M costs necessary to ensure continued effectiveness of the alternatives. Capital costs include the sum & the direct capital costs (materials and labor) and indirect capital costs (engineering, licenses, permits). Long-term O&M costs include labor, materials , energy, equipment replacement, disposal, and sampling necessary to ensure the future effectiveness of the alternative. The objective of the cost analysis is to evaluate the alternatives based on the ability to protect human health and the environment for additional costs that may be incurred . A summary of the costs for each alternative is as follows:

2- 1 5 F . :

_PROa 3 6037884 h_S

_ OUt
- RODWINALI OU1ROD . FNL April 1996

## • , -", . •.... 815 22 Final Record of Decisio n Operable Unit 1

Ellsworth Air Force Base, South Dakota

Alternative No . 1 (No Action) Total Capital Costs $0 Total Annual (Sampling /Analysis) Costs $0 30-Year Present Value for Annual Costs $0 A nnu a l Cost = $0 Years = 30 D iscount Rate = 5% TOTAL 30
- Year Present Value $0
=
Al ternative N o . 2 (Source Area Soli Treatment and Gro u n d-w ater Co n tainment) Total Capital Costs $78 2,000 Total Annu al (Sampling /Analysis/O&M) Costs $150,000 30-Year Present Value for A nnu a l Costs $ 2,306,000 Annual Cost = $ 25,000 Years = 30 Discount Rate = 5% TOTAL 30 - Year Present Value $3,088,000

Alternative No . 3 (Source Area So U Treatment and Ground- water Treatment) Total Capital Costs $986,000 Total Annual (Sampling /Analysis/O&lV D Costs $96,000 30-Year Presen t Value for Annual Costs $ 1 , 479,000 Annual Cost = $25,000 Y

ears = 30 Discount Rate = 5% TOTAL 30-Year Present Value $2,465,000 The majority of the costs for Alternatives 2 and 3 are from long-term monitoring and maintenance. The capital costs for Alternative 3 are approximate l y $204,000 greater th a n the capital costs for Alternative 2. This is due to th e additio n al ground-water extractio n wells and /

or trenches needed to remediate the ground water under Alternat{ve 3 rather than contain the ground water under Alternative 2. Because Alternative 2 will operate approximately 10-15 years longer than Alternative 3, the long-term monitoring and maintenance costs are much greater for Alternative 2. These addition a l lon g -term monitoring and maintenance costs are much greater than the additional capital costs to remediate the ground water under Alternative 3. Alternative 3 2 -1 6 F . '

LPROJ : 6037884

_Sl OUI
- ROD I FEVALI OUIROD . tq4L April 1996

## ..... 815 23
. Final Record of Deci sion Operable Unit 1

Ellsworth Air Force Base, South Dakota is the most cost-effective alternative. 2.8.8 S tate A ccep t a n ce T he a sse ssm e nt of th i s cri te ri on co n s ide r ed th e Stat e's pre f ere n ce s fo r or c once rn s abou t th e al ternativ es The State concurs with the selected remedy. The S tat e pr o vided comments on the remed i al investigation, feasibility study, and Pr o posed Plan. In accordance with the requirements of the NCP, the St a te of S o uth Dakota was also provided the opportunity to review and c o mment on the ROD. As a result of that review and after incorporating adequate resp o nses to the comments into the respective documents, the State concurred with the remedy. 2. 8 .9 Com mu n ity Accep ta nce Commen t s offered by the public were used to assess the community a cceptance of the proposed alternative. The community expressed their concerns about the selected remedy during the public comment period. The questions and concerns of the community are discussed in detail in the Responsiveness Summary, which is Appendix B of the ROD. Community members did not express any concerns about the Proposed Plan which would require a change in the chosen alternative. 2. 9 SELE C TED AL TE RNATIVE B a sed on the requirements of CERCLA, comp arative anal y sis of the nine cri t eria, public comments, and in consultation with EPA and the State, the Air Force has determined that the selected alternative is Alternative 3, Source Area Soil Treatment and Ground-water Treatment. This alternative includes institutional controls in conjunction with physical modification of the OU to reduce potential risk. Five-year reviews of the remedy will be required because contaminants at OU-1 will remain above health-based levels following completion of installation of the extraction components of the remedy. Major components of Alternative 3 are: • C o ntinued operation of the IRA wh i ch consists of(l) SVE to remediate a portion of the s o urce area s o ils and (2) gr o und-water wel l s and an existi ng c o l l ecti o n trench to rem o ve c o ntaminated ground wat er near the s o urce area. • Installation and use of additional SVE wells, ground-water wells and /

or collection trenches. • S o il gas and contaminat ed ground water would be treated at the IRA treatment plant. The water effluent will either be discharged to surface water, injected underground, o.rdi s charged t o the Base waste-water treatment plant. • Implementing institutional contr o ls (deed and land use restricti o ns) to restrict the future use of the area while the remedy is being implemented. 2- 1 7 F'_PROJ q 6037884 brS2 0UI' ROD bTINALI OU1ROD . FNL April 1996

## -., 815 "'24 Final Record of D ecision Operable Unit 1

Ellswor th Air Force Base, South Dakota
• Pr o viding for l o ng-term gr o und-wat er m o nit o ring at the OU t o identify " development of future risks associated with the OU. Providing long-term maintenance of the remedial actions taken at the OU. Each of these items is discussed b e low. Continued O peration of the IRA T he I RA c onsis t ed of ( l ) S V E to rem edia te a po rti o n of the s our ce are a s o i l s and (2) gr oundw at e r wel ls a n d an existin g c ol l e c tion tre n ch to r emov e c on t am i nated gr oun d w at e r near the so ur ce ar e a . T he I RA also i n c luded th e co n s tru c ti on o f a tr eatm e nt p lan t f or the tr ea tm e n t of th e soil gas and c ontam i na t ed gr ound w ater. The I RA wil l be o p er at e d an d the a d d i tional SV E w e l ls , gr ound- w at e r we lls, and c oll ection trenche s d e s cribe d bel o w w ill be a d ded t o the sy s tem . SVE W ells, Ground-Water Wells and /

or Trenc h es The objective of this alternative is t o decrease soil contaminant concentrations within the burn-pit to the levels listed in Table 2-2 and to remediate the shallow aquifer to levels listed in Table 2-1. T

he area targeted for SVE is the bum-pit area (Figure 2-4). Additional SVE wells will be placed in the burn-pit area to remove soil contamination that was not addressed in the IRA. The number and placement of the SVE wells will be further evaluated during the design. Ground-water wells and /

or collection trenches will be installed at OU-1 to remediate the contaminated shallow aquifer at OU-1 to the levels listed in Table 2-1. The number and placement of wells and/or trenches will be evaluated during the design. The ground-water wells and trenches will co llect and remove c ontaminated gr o und water at OU-1. The aquifer is expected to be remediated in 10-15 years. Trea t men t Extracted soil gas , condensate from the SVE wells , and ground water removed by wells and trenches will contain both VOCs and petroleum hydrocarbons. T hese contaminants will be treated at the treatment plant built for the IRA . Treatment of the soil gas and contaminated ground water consists of filtration, air stripping, activated-carbon adsorption, and thermal oxidation. The water effluent from the treatment plant is expected to be discharged into a drainage which flows into Pond 001. The effluent will be monitored prior to discharge to determine the effectiveness of the treatment system. Efflue n t discharge standards an d mo n i toring will be determined during the design phase and are subject to State and EPA reviews and approvals. Underground injection or discharge to the Base waste-water treatment plant may be chosen as the discharge option based on the allowable discharge standard. The expected surface water discharge will comply with the requirements of the Clean Water Act. Off-gas from the thermal oxidizer will be monitored to ensure compliance with Federal, State, and local requirements 2- 1 8 F .' WROJ l dO37884

_S

_ OUI
- ROD

_FINALI OUIROD , FNL April 1996

## 815 25 F i nalRecordo/Dec i sionOperableUnit I El1

_ orthAirForceBase,SouthDakota
un dertheprovisio n softheCleanAirAct. Instituti o nal C ontrols Insti tutional controls will be imp l emented to prevent human exposure t o contamin at ed soil a nd ground water. These controls wilt include: (1) issuing a continuing order to restrict on-site worker acc e ss to contaminated soil, and to restrict or con trol temporary construction activities unless proper protective equipment is worn; (2) filing a notice with the State to recommend denial of water appropriation permit applications to install ground-water wells within the area of contamination and any area which may be effected by potential contaminants; (3) filing a notice to the deed detailing the restrictions of the continuing order and ground-water well restrictions; and (4) a covenant to the deed in the event of property transfer. Continuing order requirements will be in effect as long a s the prop e rty is owned by Ellsworth AFB and the remedial action has not reached remediation goals. In the case of the sale or transfer of property within OU-1 by the United States to any other person or entity, the Air Force will place cov e nants in the deed which will restrict access and prohibit disturbance of contaminated soils or th e remedial action without approvaI of the United States. These covenants will be in effect until removed upon agreement of the State of South Dakota, the US. Environmental Protection Ag e ncy, and the U.S. Air Force or their successors in interest. The Air Force will also include in the deed the covenants required by section 120(h)(3) of the Comprehensive Environmental R e sponse, Compensation and Liability Act (CERCLA) , which include (1) a warranty that the United States will conduct any remedial action found to be r e quired by law after the date of the transfer; (2) a right of access in behalfofEPA and the Air Force or their succ e ssors in interest to th e property to participate in any response or corrective action that might be required after the date of transfer. The right of access referenced in the preceding sentence shall include the State of South Dakota for purposes of conducting or participating in any response or corrective action that might be r e quired aft er the date of transfer. L ong-Term Moni t o ring and Maintenance A maintenan c e p r ogr am w ould b e estab li sh ed to en s ure th e l o ng-te rm integrity o f th e r emoval a n d treatment s y s tem . T h e maintenan c e p r ogram would include develop m en t of s tandar d o p e r ating pr ocedu r es (SOPs ) to p r ovide f or ins p e c tion s , r e p ai rs , and leak re sp onse a c tion s. A long-term monitoring p r ogr am wi ll b e deve l oped and i m plemented du ri ng r emedial a c tion and i s subj e c t to ap proval of b oth E PA and S D DEN R. Contaminant c on c entr a tion s f ro m th e tr eatment plant vap or s tr ea m and tr eated gr ound w a t e r w ill b e m o nit o r ed t o evaluate th e e ff ectivenes s of th e sy s tem in removing VO C s f rom th e c ontaminated media
. Co n ta mi nant c on c entr ations in th e b u rn-p i t ar ea and in th e gro u nd w ate r w ill also b e m onito r ed . Continued ana l y s is and monitoring of the gr ound- w ate r remedia l a c tion sy s tem pe rf o rm a n c e wi l l b e c ondu c ted to dete rmine if th e r e m ediation s ystem i s ap p roa ch ing an a s ymptoti c level d u e to p h ys ic al limitations of th e s ite, o r th e b ene fi ts of th e r emedial a c tion n o longe r ju s tify long-te rm op er a tion of th e system . R emediation goal s and th e r emedial alte rnative w ill b e re-eva l uated at th at time
. 2- 1 9 K'k PRO .A6037884

_ OUl
- ROD

_FINAL

_ OUIROD . FNL April 1996Final Record of Decision Operable Unit 1 Ells w orth Air Force Base , South Dakota This alternative will meet the remedial action objectives and reduce the potential risk at OU-1 by treating contaminated ground water to levels considered safe for public drinking water and by preventing future contamination of the shallow aquifer by reducing the volume of contaminants in the soil above the shallow aquifer. This will be achieved by the installation of ground-water wells and /

or collection trenches , installation of SVE wells, and treatment of removed ground water and soil vapor. Alternative 3 would achieve significant risk reduction at the OU by treating ground water to reduce contaminant concentrations to below the MCLs. The selected alternative will be protective of human health and the environment and will comply with A RARs. 2 . 10 STATUTORY DETERM I NATIONS The selected remedy meets the statutory requirements of Section 121 of CERCLA as amended by SARA. These requirements include protection of human health and the environment, compliance with ARARs , cost effectiveness, utilization of permanent solutions and alternative treatment technologies to the extent practicable. The selected remedy represents the best balance of tradeoffs among the alternatives considered, with respect to pertinent criteria, given the scope of the action. The manner in which the selected remedy meets each of these requirements is discussed in the sections below. 2 . 10.1 Protec tion of Hu m an Health and th e E nviron m en t The selected remed y addresses he a lth and environmental issues that were identified in the OU-1 RI report. Specifically, the alternative:

• Reduces contaminant concentrations in ground water to MCLs. • Reduces the potential infiltration of contaminants to the ground water. • Prevents unauthorized access and use of the area while remediation is t aking place thereby preventing exposure to contaminants by Base personal and potential future residents. ' ...... • Provides for long-term monitoring of ground water to identify potential future risks associated with OU-1.

2

- 20 F't

PROJ

_ 603 7 884 V z ' S

_ OU1
- ROD I FINAL

_ OUIROD . FNL April 1996

## 815 2 7 F

i nal Re cord o f Decis i on Operable Unit 1 El[sworth Air Force Base, South Dakota 2.1 0 .2 C o mpli an c e w i th ARARs Alternative 3 will meet Safe Dri nking Water Act MC L s and S o uth Dako ta Gr o und Water Quality Standar d s (ARSD Chapte r 74: 0 3:15). T reated discharge water w i ll c o mply with the requirements o f an NPD ES permit. The pr o p o sed SVE system will reduce c o ncentrati o ns o f JP-4 t o c o mply wi th S o u th Dako ta P e tr o leum-C o ntami nat ed S oi l s regu l atio ns. Add iti onal informatio n ab o ut ARAR c o mpliance is contained in Secti o n 2.8.2. 2.1 0 .3 C o s t Ef f e cti venes s T he selected remedy has been determined t o pr o vide o verall effecti veness pr o p o rti o nal t o its c o sts and is theref o re c o nsidered c o s t effective The presumptive remedy pr o cess insures c o st effecti ve remedies are ch o sen. The estimated c o sts o f the selected remedy are less than the c o sts assoc i ated with a similar al t ernati ve that utilizes o nly gr o und-water c o ntai nment. The selected remedy pr o v i des a higher degree o f pr o tectiveness at a l o wer c o s t than the c o ntainment alternative. All the techn o l o gies included in the remedy are readily implementable and have been widely used and dem o nstrated t o be effecti ve. 2. 1 0. 4 Utili z atio n of Per m anen t S olution s and Alt e rnative Treatm en t Te c hnologi es to the E x t en t Po ss ib le T he selec ted r eme d y r epresen t s the maximum extent t o which p e rmanent s ol utio ns and t r eatment t echn olog ies c a n b e u tilized in a c o s t- effective manne r f o r OU-1 EPA has es tab lishe d that SVE h a s p ro ven effective i n reme d iatin g s o ils c o n t ainin g VOC s . This alte r native prevents unauth o rize d a ccess an d p ro vi d es f or l on g- term gr o un d water m o nit or in g to d e t ect m o vement o f chemical s fr o m the area . A revie w wilt b e co nd uc t e d n o l ess o fte n tha n eve r y fi ve years af t e r the si gn i ng o f the g OD t o e n su r e the r eme dy c o ntinues to provi de a d equate pr o tecti o n o f human heal th an d the env ironme n t 2. 1 0.5 Pr e fere n ce for Treatm en t a s a Principal Ele m ent Treatme n t of s oil w ithi n th e fo rme r F PTA and c ontamina t ed grou n d w ater sa tisfi e s th e s tatu t o ry r equire m en t of tre atme nt a s a p rin cip al el e m ent . 2.11 DOCUMENTATION OF SIGNI F ICANT C H ANGES The s e le ct ed a c tion i s the same a s th e pref e rred al tern ative present ed in th e Prop o s e d Plan for OU-1 remedial action. Ther e hav e been no changes r e lative to the Proposed Plan.

2

- 2 1 t _'h °ROa 2 603 7 884

_S

_ OUt
- ROD

_FINALI OU1 R OD . FN ' L April 1996

# !i i

7 m 4



# _ _ _ _

## 815 29

-_

<



### ._ ,__ _ _ _ _ ._ _-_

_. .. 

# _ __]_. : ] 

# ] ooio_ o

## ..... 815 30 Final Record of Decision Operable Unit 1

Ellsworth Air Force Base, South Dakota
3.0 LIST OF A C RONYMS AND A BBREVI A TIONS 1,2-DCA: 1,2-Dichloroethane 1,1-DCE: 1,1-Dichloroethylene 1,2-DCE: 1,2-Dichloroethylene ACC: Air Combat Command ARARs: Applicable or Relevant and Appropriate Requirements ARSD: .Administrative Rules of South Dakota CERCLA: Comprehensive Environmental Response, Compensation and Liability Act CFR: Code of Federal Regulations COC: Chemicals of Concern CRP: Community Relations Plan CWA: Clean Water Act EAFB: Ellsworth Air Force Base EPA: Environmental Protection Agency FAWQC: Federal Ambient Water Quality Criteria FFA : Federal Facilities A greement FPTA: Fire Protection Training Area FS: Feasibility Study IRA: Interim Remedial Action IRP: Installation Restoration Program JP-4: Jet Propulsion Fuel Number Four; contains both kerosene and gasoline fractions. MCL: Maximum Contaminant Levels gg

/ kg: Micrograms per kilogram gg

/ L: Micrograms per liter NCP: National Oil and Hazardous Substances Contingency Plan NPDES: National Pollutant Discharge Elimination System NPL: National Priorities List O&M: Operation and Maintenance OSHA: Occupational Safety and Health A dministrati on OSWER: Office of Solid Waste and Emergency Response OU: Operable Unit PAIl: Polynuclear Aromatic Hydrocarbon PCE: Perchloroethylene; liquids used in degreasing or paint removal ppm: Parts per Million RA: Remedial Action
3-1

## 815 31 Fi n a l Record of Dec & ion Operable Unit 1

E

l lsworth A ir Force Base, South Da k ota RAB: Restoration Advisory Board RAO: Remedial Action Objective RI / FS: Remedial Investigation / Feasibility Study ROD: Record of Decision SARA: Superfund Amendments and Reauthorization Act SDDENR: South Dakota Department of Environment and Natural Resources SOP: Standard Operating Procedures SVE: Soil Vapor E xtraction SVOC: Semivolatile Organic Compound TCE: Trichloroethylene TPH: Total Petroleum Hydrocarbon USA /

: United States Air Force VOC: Volatile Organic Compound

3-2 F ..k PROJ t 6037884 k._'_ OU1 . ROD

_FINALl OUIROD . FlVL April 1996

## 8 15 O 3 2 Final Record of Decision Operable Unit 1

Ellsworth Air Force Base, South Dakota

APPENDIX A FIGURES

## 815 33 iiiii


### __.J
1_ _om_A_'_ SOUTH DAKOTA

WY OMIN G I " Q ' "

_ ' -

ELLSWORTH AFB



## ........ 2 ......., ,,, , , .._ o .:..__J ................

D 5 10 I P_ 1 S c o l e ; n U _l es < APP R OX IM AT[

, <

_ c
_" L u i i -2 i '

_l EL LS WO RTH ELLSWORTHAF'B A REALOC A TIONMAP o '
. AIR FORCE BASE

= _i PROJECT M G R DESIC;N E D BY DRAWN BY CHECKED BY S DATE

_ 1 MRG SHO W N OCT95 I 60378
. 85 I 2 -1

## 815 3 4

i

IN S TALLA T ION BOUNDA R Y WEA P O NS S T O RAGE ! 0U - 8 !

j . .... , O U -3

DEBRIS -- _ BURIAL S T.

_ AREA



# _/ -- - =- I _2 _. .ou_ , ._ ,

-- _ARNOLI A REA I I

_ R
. I SP AA_

Z WASTE WA TER o 1200 2 4 00

_ [-- -- r l PL AN T LEGEND J- h i • OPERABLE UNITS OU -- 1 HO U SI N e -%. OU-1 FIRE PRQ 'T ECTION TRAINING AREA ( FT-01) _, __ 0U -2 LAN D FILLS 1 & 6 (LF- 0 2) OU - 2 OU -3 LA N D FI L L 2 ( L F-O3) IND US T RIAL O U -4 LAN D FILL 3 (LF- 04 )

_ O U -5 LA ND FI LL 4 (LF- 0 5) GATE O U-6 L A NDF I LL 5 (L F - O6 ) OU- 7 LOW L EVE L RA O I A T{ON WA ST E B U RI A L AR E A ( RW - 07) OU-8 EXPLOSM[ ORDNANCE DISPOS A L ARE A & PRAMITOL SP I LL (S B -11) / OU-9 OLD AUTO HOBBY SHO P AREA (0T-15) O U -lO N OR TH H AN G A R CO MPL EX (S T-19) O / OU - I I BAS EW IDE G R O UN D WATE R



# _ 0 ° - ,2 , AROF , LL,

0. , o, N w &__
< < ,C' / ;

_ ' . _-_ _ E LL S W ORTH ELLSWORTHAFB S I TELOCAT I ON MAP :

_ A IR FOR C E BA SE R AP ID{:f lY, SOU TH _OTA Z cn 

# _g ! S TAFF A S SHO WN CT 9 " I 60 378.84 I 2-2

## 815 35

\ \\

_ / OU- 1 BO U NDA R Y 

# \\

_ // =

_ -- I_ 

# -,-- _ 2 r_l I 

# N\ o{ , "_'I
I 

# \ , RE C ENT B U RN Pi T AR EA O F HISTORICAL B U RN PIT AREA

_ • 

# \ , /

BO UNDARY1 T R AIN I N G AR EA BOUNDAR Y F ENCE 

# \ / f

/

_°°' ° _°° ' LEGEND SCALE ' ' ' S UR FAC E DRA I NAGE EPA lgg l
. B URN P IT H ISTOR ICALAR E A SF R OM A E R I A L P H O T O C RAP HS , 19 52-1 gg 2

ELLS WORTI- I EL L S W OR TH AFB 1 S ITEAREA AIR F O R CE BASE

_ CITY , SOUTH OA KO T A M G L AS SHO W NI OCT g5 I 6 037 8 .84 2 - 3

## 8]5 36 --

IIIII •

;, _=_7_X_ / R EA 0 A AINM_ / N_I

" JfJ_l 3 0 1 0 15 _) SG930 1 07

12 . " _ S 1 I. i 0 } 39

._,_0

_ ( /

_ E XTE N T OF HISTORICA L _) _., o,. , _7_, _ _t_y " BU R N PIT A REA S 

# ,_ , / ' _ . , o ,,. I LE GE N0


# ' I __ , _.io,,, _:

_ , , o ,_, I _AR_ O FATTA,NMENT , . ,., . . o . _ ,.oI \ I_ , 9 9`3R,S O L $e930129

_ _ __ * i_2:1__' _ :)"r ' e J_ ° '_"I BOR, N G LOCAT,ONS

.. _ _ i,g3 o, _3 MONITO R IN G / S O IL o =

_ _"_ " (_) s _0,_ ( ;_ _N LI BO R IN G LO C AT IO N .



## _ \\ _ \ _[_'_ 3' _ 0 o ' 0 _, o _ ,, _ \\ _ \ \ \" ,_ _ I

_, _ TITLE : FI G URE: D W N BY: APP'D : STAFF T R

_ , _ ELLSWORTH AR E A OF A TT AINM E NT F O R 2-4 AIR F O R C E B A SE S OU RCE-AREA S O ILS DA TE: PJT NO: MAR 9 6 6 0 3 7 8.8

_

## 81 5 37
1 

## r I


# I o' _
. - GROU N % -

_ - -_ER, 1 \ _ / AR EA OF A?iA" i _IM / E NT -

_



# = C

, 1_

t \ \ _ ///

' /

_

/ ' /_ ' 7 " // _ I

_ . Pg_ BORIN G L OC ATI ONS /

_ \_ _ "___\" _. (::_,_ = _,_ MONIT O RING / SOI L

_ _X t_P B _ _/ XX L BO R IN G LOCA TI ON [

/
. =2, _ TITLE: FIGURE: D WN BY : APP'D :

_ _ S TAFF T R _! ELL S WOR TH AR E A OF ATTAINM E NT FOR AI R F OR CE BASE 2 -- 5

_ = _' GR O UN D WATER D ATE: PJT N O:

_ MA R 95 60378.8 ,_Final Record of Decision Operable Unit 1

- " Ellsworth Air Force Base, South Dakota

iAP P E NDIX B RE SP ONS I VE NES S SU MMA RY

F ._PRO . . q 60 1 7884 1 FSq OU1
- ROD h V

_

IAL } OU1ROD . FNL April 1996

## - . ; 815 39 Final Reco r d of Decis ion O p er a ble U nit 1 ;." Ellsworth Air Force Base, South Dakota Respon s ivenes s Su mmary Remedial Action at Operable Unit One Ellsworth Air Force Base, South Dakota
I . O vervie w The United States Air Force (USAF) established a public commen t period from A u gust 8 t o October 16, 1995 for interested parties to review and c omment on remedial alternatives c onsidered and described in the Proposed Plan for Operable Unit One (OU-1). The Proposed Plan was prepared by the USAF in cooperation with the U.S. Environmental Prote c tion Agency (USEPA) and the South Dakota Department of Environment and Natural Resources (SDDENR). The USAF also held a public meeting at 6:30 p.m. on September 26 , 1995 in the 28th Bomb Wing Auditorium at Ellsworth Air Force Base (EAFB) to outline the proposed remedy to reduce risk and c ontrol potential hazards at Operable Units 1, 2, and 4. Some of the public comments pertained to the selected remedies in the Proposed Plans for all the operable units. Rather than attempting to separate out the comments which pertained to an individual operable unit, one Responsiveness Summary was prepared to address all the comments for all the operable units. The Respo n siveness S u mmary provides a summary of commen t s and questions pertaining to OU 1, received from the community at the public meeting and during the public comment period, as well as the USAF's responses to public comments. The Responsiveness Summary is o rganized int o the following sections: • Background on Community invo l vement • Summary of Comments a nd Questions Received During the Public Comment Period and USAF Responses • Remaining Concerns The selected remedy for OU-1 is alternative 3, source area soil and ground-water treatment, which includes the following major components: • Continued oper a tion & the interim remedial action (IRA) which consisted of contaminated ground-water removal, soil vapor extraction (SVE), and treatment; • Installation of additional SVE wells within the historical bum-pit area to be added to the existing IR A SVE system;
B-1 F "TJROJ I 6037884_' S

_ OU1
- ROD

_ INAL

_ OUIROD . FNL April 1996

## " : 815 4O _, Fi nal Rec o r

d o f Decision Operable Unit 1 Ellsworth Air Force Base, South Dakota • Removal of contaminated ground water using additional ground-water wells and collection trenches to be added to the IRA ground-water recovery system; • Treatment of ground water at the existing IRA treatment plant; • Institutional controls for the area; • L o ng-term m o nit o ring; and, • L o ng-term o per a tion and maintenance of equipment. 2. B ackgr o u n d on C o mmun ity I n v o lv e m en t On Aug u st 30, 1990 EAFB was listed on the USEPA ' s N a tional Priorities List (NPL). A Federal Fac i lities Agreement (FFA) was signed in January 1992 by the Air F o rce, EPA, and the State and went int o effect on Apri l 1, 1992. The F FA esta b lishes a procedural framework and schedule for de v eloping, implementing , and mon it o r ing appropri ate resp o nse acti ons f o r EAFB. Community relati o ns activiti es that h a ve taken place at EAFB t o date include:

• F FA p ro c e s s . After p r e paration of the FFA by the USAF, EPA, a n d S D DE NR , the document was publ i shed for co m ment. The FFA became effec tive April 1, 1992.

• Ad ministrative Record. An A dminis trative Rec o rd for i nf o rmation was established in Building 8203 at EA F B The Administrative Record contains i n formation used t o suppor t USAF decisi on -making All the d o cuments in the Administrative Record are available t o the public. • In f ormation re po s it o rie s . An Administrative Record outline is located at the Rapid City Library (publ i c repository) • C o mmun i ty Relati o n s Plan ( C RP). The CRP was prepared and has been accepted by EPA and the State of South Dakota and is currently being carried out. An update to this plan will be prepared in 1996.

• R e s t ora ti o n A dvi s o r y Bo ard (R A B ) . The R AB has been f o rmed to facilitate public input in the cleanup and meets quarterly. In addition to USAF, EPA, and South Dakota oversight personnel, the RAB includes community leaders and local representatives from the surrounding area.

• M ailing li s t. A mailing list o f all interested par t ies in the community is maintained by EAFB and updated regularly.
B-2 F: LPROJ

_ 6037884 hT Sl OUI
- ROD

_[NAL

_ OUIRODA

_ NL April 1996

## =. 4l

-. Final Record of Decisio n Operable Unit 1 Elts w orth Air Force Base, South Dakota

• F a ct s hee t . A fact s h e e t d e scribing th e status of the I RP at EAFB was d i stributed t o the mailing list addresse e s in 1992. • Op e n h o use. An information al meeti ng o n the status o f the IRP a n d other environmental efforts at EAFB was held on May 6 , 1993. An open house was held November 16, 1995 in conjunction with the Restoration A dvisory Board meeting. Information on the status & environmental efforts at EAFB was provided at the open house. • News p ap er artic les. Articles have been written for the base newspaper regarding IRP activity. T

he Proposed Plan for this remedial action was distributed to the mailing list addressees for their c o mments. Additional copies of the Proposed Plan were available at the September 26, 1995 public meeting. A transcript of comments, questi o ns and resp o nses provided during the public meeting was prepared. 3 . S u mmary of C o mm ents and Questions R eceive d Durin g th e Publ i c Co mment Period and USA F Responses Part I - S u mmary and R es pon s e to Loca l C o mmunity Conc e rn s R evie w of the w ritten tr an sc ri p t of th e pub li c meeting did n o t indi c ate c ommun i ty o bj e c tion s to the p ro p osed re me di a l action
. No writt en c omments w ere re c eived du ring th e p ub l ic c omm e nt pe rio d . The majority & the comments received during the public meeting for OUs 1,2 and 4 were in the form & questions about the remedial investigation findings, the remedial action; i.e . , what would be done, how it would be done, and what effects the action might have. In addition, one question addressed purchase of off-Base property. Representatives & the USAF were available to provide answers to the questions and also provided an overview presentation during the meeting to describe the proposed actions. The following are questions and responses pertaining to OU-1. For questions and responses pertaining to OU-2 and OU-4, refer to the Records of Decision for these OUs. Part H - Comprehensive Response t o Specific Tec h nica l , Legal and Miscellaneous Q uestions The comments and questions below have been numbered in the order they appear in the written transcript of the September 26, 1995 public meeting. Comment 1. Jan Deming Aske d about whether the stream running from the northeast to the southwest in OU-1 B- 3 FqPROJ

_ 6037884 h_S

_ OUt ' ROD TZlNAL

_ OUIROD . FNL April i996

## 815 42 u - r Fi n al Record of Decision Operable Unit 1 Ellswor th Air Force B ase, South Dakota was contaminated, or was transporting contaminants. Re s p o n s e 1: Evide n ce of jet fuel and pesticides were f o und in the sediments. T he human hea lth and ecological risk assessments indicated that there was no unacceptable risk to human and ecological receptors. The storm drains were deferred to O U- t 1 to allow additional investigation of the ecological conditions on the Base. The oil / water skimmer in Pond 001 will remove any contamination floa t ing on the pond surface ira fuel spill were to occur upstream of the OU. The monthly NPDES sampling for a range & chemicals helps ensure that no contamination is going offBase. 4 . R em a i n i n g C o n cer n s Based on review of the transcript of the oral comments received during the public meeting, there are no outstanding issues associated with implementation of the proposed remedial ac t ion.

B- 4 F ..._PRO .A6037884WSI OUI -. _OD i FINALt OUIROD . FNL April 1996

## •

_ 7 5 43


# F INAL PAGE

ADMINISTRATIVE RECORD



# FINAL PAGE

## 8 15 4 4 : s .... 

# FINA L PAG E

ADMINISTRATIVE RECORD



# FINA L P A GE