EarthTech 30Campus 33 Drive P 763.551.1001 Suite 290 F 763.551.2499

AT]colntmational Ltd.Company Minneapolis, MN 55441 www.earthtech.com

February21,2005

Area Engineer,BlackHillsArea Office

U.S. ArmyCorpsof Engineers

631 SaintAnneStreet,Suite 101

RapidCity, SouthDakota57701-4667

Subject:Contract DACW45-03-D-0032, DO-3

Pride Hangar Source Area Treatment/Updated Work Plan

EIIsworth AFB, South Dakota

Serial Letter ERS-3-RA-158

FXBM 20047001

Dear Mr. Mailander:

The purpose of this letter is to present an updated work plan for the in-situtreatment of

trichloroethene(TCE) at the Pride Hangar site source area. The Pride Hangar Site and

groundwater plume are shown in Figure 1. A detail of the TCE source area is shown in

Figure2.

Source area treatments were initiated based on high TCE ground water concentrations

measuredinthe excavationof the formersolventundergroundstoragetank (UST). Stimulation

of bio-dechlorinationwas selectedfortreatmentinthe saturatedsoiland groundwater, and soil

vapor extraction(SVE) was selectedfor the vadoseor unsaturatedzone. The statusof each

treatment and recommendationsfor continued treatment and monitoringare presented in

Sections2.0 and 3.0.

This work plan was submitted initially in Serial Letter No. ERS-03-RA-149 dated

December21,2004. Commentswere receivedfromSouth Dakota Departmentof Environment

and Natural Resources(SDDENR) in a letter datedJanuary 7, 2005. Those comments,and

others, were discussed by the Remedial Project Manager group in a meeting held

January25, 2005, at EiIsworthAFB.This planhas been revisedbased onthe DENR comments

and RPM meetingdiscussion.Annotatedcommentsare attached.

1.0 SCOPE/_D PROPOSED MONITORING- IN-SlTU GROUND WATER TREATMENT

In-situ remediationof the Pride Hangar groundwater source area was initiatedto promote

bio-dechlorinationof chlorinatedvolatileorganiccompounds(VOCs)in groundwater. The scope

of this work was described in a work plan dated September 3, 2003 (Serial Letter

No. 1-54-RA-301). This work includedinstallationand initialmonitoringof two new monitoring

wells in the target area (MW041101 and MW041102). Injectionof emulsifiedsoy oil was

performedafter baselinesamplingofthe newwellsand existingwell(MW941102). The injection

pointsandmonitoringwelllocationsare shownon Figure2.

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EarthTech ATyco..IotematieealLtd. Company

Mr. MarkMailander

U.S.ArmyCorpsofEngineers

February 21,2005

Page 2

Emulsified soy oil was injected into the ground water at 14 direct push soil borings within this

area during the period January 29 through February 3, 2004. Approximately 100 gallons of

dilute, emulsified soy oil was injected at each point. A proprietary soy oil emulsion concentrate

from EOS Remediation, Inc. (EOS), was used. This product was selected due to its

performance at other sites. The EOS product is a concentrated, stable emulsion containing

soy oil, lactic acid, emulsifier, and vitamins. The injection procedure involved diluting the EOS

concentrate at a 4 to I ratio with water, driving the direct push rod to the depth of competent

shale, then injecting as the rod was pulled up through the saturated zone.

It1 addition to the EOS injection, a culture of known TCE degrading bacteria (purchased from

Regenesis, Inc.) was injected at two direct push locations near MW041101 and MW041102 in

May 2004. This work was performed in coordination with similar work being completed at OU-4.

Existing monitoring well MW941102 and new wells MW041101 and MW041102 are used to

monitor the bio-dechlorination progress on a monthly basis following injection. Existing

well MW941102 is side-gradient of the source area. MW041101 is in the center of the former

UST excavation area and MW041102 is southwest of the UST excavation area and the injection

area.

1.1 Treatment Status

Monitoring results for ground water samples collected from wells MW941102, MW041101, and

MW041102 are presented in Tables 1 through 3 and Figures 3 through 5 for the period from

pre-injection through January 2005. Monitoring resultsat MW041101 show a rapid initial

reduction in TCE concentration during the first 3 monthsfollowed by slight reduction over the last

8 months. TCE concentration has dropped at MW041101 from 16,000 to 1,018 micrograms

per liter (ug/L). Ground water TCE concentrations at MW041102 show an initial decrease

followed by an increase, then a significant decrease with an overall reduction from 19,000 ug/L

to 1,270 ug/L. No significant change in ground water TCE concentration was observed in

side-gradient well MW941102. The increase in TCE concentration at MW041102 may be due to

varying ground water flow directions especially in the summer and fall.

At MW041101 and MW041102, ground water concentrations of the first biological reduction

product, cis-di.c.hloroethene(cis-DCE) were below the detection limit until 6 to 7 months after

injection. The January 2005 concentrations were 122 and 1,201 ug/L, respectively.

Cis-DCE concentrations at MW941102 remained below 10 ug/L. Vinyl chloride was not detected

in any of the wells; however, the detection limits are above the drinking water standard of 2 ug/L

(detection limits have ranged from 6 to 1,000 ug/L).

Sulfate concentrations in MW041101 have decreased significantly from 430 to 35.7 milligrams

per liter (mg/L). The variation of suffate concentration with time closely follows the pattern for

TCE. Sulfate concentrations at well MW041102 remain high, ranging from 1,043 initially to

2,350 mg/L. Sulfate concentrations at MW941102 did not change significantly.

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EarthTech

ATyco International Ltd.Company

Mr. Mark Mailander

U.S. ArmyCorps of Engineers

February21, 2005

Page 3

Chemical oxygen demand (COD) monitoring indicates that sufficient electron donor

(soyemulsion)remainsat MW041101; however, relativelylow concentrationsare present at

MW041102. The pre-injectionand most recent COD concentrationsfor the two wells are

970/7,280 and14/2.1 mg/L,respectively.

The COD and sulfatedata indicatethat the oil injectiondid not supply a significantmass of

electrondonorto MW041102. Reviewofwaterleveldataindicatesa northeasterlygroundwater

flow inthesourcearea as opposedtoa southeastflowforthe largersitearea, explainingthe low

COD concentrationsinthissoutherlywell. The groundwaterflowdirectionforthe sourcearea is

presentedin Figure2 based on the March 9, 2004, water level data. The water level will be

measuredeachmonthat all monitoringwellstodeterminethe groundwaterflowdirection.

In additionto VOC and inorganicgroundwatermonitoring,specificmicrobiologicalanalysiswas

performed on ground water samples collected from MW041101 and MW041102 on

June7,2004. The purpose of this analysis was to measure the concentration of

Dehalococcoides(DHC), the bacteriumprovento be capableof completebio-dechlorinationto

ethene. Researchindicatesthat severaltypes of bacteria can convert TCE to dichloroethene

(DCE). However, the DHC bacteria is needed to reduce DCE to ethene. Polymerasechain

reaction(PCR) testingfor numbersof DHC and targetgenesper milliliter(mL)was performedby

Microbial Insights, Rockford, Tennessee. The PCR test results show relatively low

concentrationsof DHC (3.22 and 15.5 cells per mL) and no detection of the target genes.

Additional microbiologicalmonitoring may be needed depending on the changes in

VOC concentrations.

Recent researchhas shownthe potentialfor a biologically-assistedgeochemicalreductionof

TCE. Additionof an electrondonorcan reducesulfatetosulfide,whichreactswithironnaturally

presentin the saturatedsoilto generateiron sulfide. Chlorinatedsolventssuchas TCE react

with the iron sulfide abiotically,reducingthese compoundsand releasing chlorideions. No

daughterproductssuchas DCE and vinylchlorideare produced. The mechanismis not fully

understoodbutis believedto convertTCE toacetylene.

Bothbiologicaland geochemicalreductionofVOCs may be occurringat the PrideHangar site.

The presenceof sulfateioncan impacteachprocess. Inthe biologicalprocess,sulfatereduction

competes for__theavailable electron donor and in the abiotic process sulfate is desired.

Decre_.sesin sulfate concentrationshave been observed at MW041101 with decreases over

80 percent. Further monitoringis needed to determine the magnitude of each of these

processes,andthusifsulfateadditionis needed.

Either directbiologicalreductionor biologically-assistedreductionvia iron sulfideformationwill

requirea sustainedsourceof electrondonor. The January2005 COD monitoringindicatesthat

insufficientelectrondonoris presentat MW941102 and MW041102. COD concentrationsrange

from5.8-2.1 mg/L inthesewellscomparedto7,280 mg/Lat MW041101.

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EarthTech ATycoInternational Ltd. Company

Mr.MarkMailander

U.S.ArmyCorpsofEngineers

February21,2005

Page4

1.2 Recommended Electron Donor Injection

EarthTech recommendsinjectionof additionalelectrondonoroutsidethe PrideHangarbuilding,

just west of MWl10402. Four new monitoring/injectionwells are proposed as shown on

Figure6. MonitoringwellMW941102 may alsobe usedfor injectionas it is outsidethe influence

of previous injections. Recent experienceat other sites indicatesthat pulsed injectionof

sodiumlactate at low concentrationis effective in terms of treatment, lateral distributionof

electrondonor,and the overallcostof injection. The followingprocedureis recommendedon a

trialbasis:

• Obtain EnvironmentalProtectionAgency(EPA) approvalfor lactate injection. A brief

letterrequestingpulsedinjectionof sodiumlactatewill be submittedto EPA and their

approvalwillbe requested. In addition,the DraftExplanationof SignificantDifferences

willbe revisedto includesodiumlactateinjection.

• After EPA approvalis received,injectbatchesof sodium lactateat 1,000-2,000 mg/L

concentration,approximately100 gallonsper well, one to two times per week. The

injectionperiodwillextendfrom March2005 to March2006.

• Injectionwillbe skippedfor 2 weekspriorto samplingat MW941102.

The proposedinjectionprocedureis describedbelow:

• Fill mobile tank ("waterbuffalo")with 500 gallons of non-chlorinatedwater with no

dissolvedoxygen.

• Add sodiumlactate,approximately0.7-1.4 gallonsusinga 60 percentsolution.

• Inject solutionby gravityto each well usingpolypropylenetubingfrom the tank to the

bottomof eachwell.

There are several sourcesof dilutionwater for the injectionsolutionat the Pride Hangar site

includingpotablewaterfromthe base system;effluentfromthe Building6908 treatmentsystem;

and effluentfrom the BG05 Base Boundarysystem. Each potentialwater source shouldbe

testedfor dissolvedoxygen and sulfateconcentrationto assesswater qualityand pretreatment

requirements. Chlorinecan be removedfrom base water by runningit throughexistingspare

activatedcarboncanisters. Alternatively,the building6908 effluentcouldbe used if pretreated

withsodiumbisulfiteto removedissolvedoxygen.

Additionof a TCE-degradingculturemay be recommendedif TCE reductionsdo not occurafter

sulfate reduction. Earth Tech recommendsuse of the KB1 culture by SiREM Laboratoryif

augmentingis needed. Previous addition of a culture from Regenesis has not produced

significantimprovementsin treatment. Alternatively,sulfate may be added in addition to

sodiumlactate to stimulate the bio-geochemicalprocess. The monitoringresults and the

bio-geochemicalprocesswillbe studiedtodeterminewhichaugmentationapproachtouse.

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EarthTech

ATycoIntmational Ltd. Company Mr.MarkMailander

U.S.ArmyCorpsofEngineers

February21,2005

Page5

1.3 Recommended Monitoring Scope And Procedures

The followingnew soil boringsand monitoring/injectionwellsare recommendedas part of this

work. See Figure6 for locations:

• Four injection/monitoringwells are recommendedwest and southof MW041102 to be

usedfor injectionof the sodiumlactatesolution. Eachwell willbe 2-inchdiameter,with

schedule 40 PVC riser and screen. The wells will be completed at the top of the

competentshale and will have a 10-foot screen. These wells will be completednear

grade.

• Three monitoringwellsare recommendedinsidethe PrideHangar. These wellswillbe

usedtotrackthedown-gradientprogressof TCE treatment(see Figure6).

The groundwater monitoringscopewill includeinitialmonitoringof the new wells, followedby

routinemonitoringof thefollowingwellsevery2 months:

• MW941102

• MW041101

• MW041102

• The three newwellsinsidethe PrideHangar

The monitoringscope includesanalysisof VOCs, COD, sulfate, and the field parameterspH,

conductivity,and oxidation-reductionpotential(ORP). Also, field measurementof dissolved

oxygen(DO) willbe performedonceper year, in the spring,to provideadditionalinformationon

groundwater redoxconditions.

The currentplanuses an off-sitelaboratoryfor allVOC, sulfate,and COD analyses. Use of the

on-sitelab is recommendedforfutureVOC analysisat the PrideHangar,as oil interferencesare

notexpected. Sampleswillbe evaluatedfor oilcontentand excessiveodor;if thesefactorspose

a problemfor.theon-sitelab,the VOC analyseswillbe performedat an off-sitelab. The current

vinylchloridemethoddetectionlimitfor the on-sitelab willbe evaluated in February2005 in an

effortto increasethe sensitivity,giventhe 2 ug/L drinkingwater standard. However,a slightly

higher detection limit for vinyl chloride is not a major concern because the Pride Hangar

treatment area is distant from the installationboundary. Also, the on-site lab will send

approximately10 percentofthe samplesto an off-sitelabfor comparison.

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EarthTech ATycoInternationalltd. Company

Mr.MarkMailander

U.S.ArmyCorpsofEngineers

February21,2005

Page6

In additiontotheabove,thefollowingadditionalmonitoringis recommended:

• Dissolved gas analysis is recommended at MW041101 and MW041102 every

4 months. Dissolvedgas analysisat the other site monitoringwells willbe performed

annuallyinthe spring. Thisanalysisincludesethane,ethene,methane,and acetylene.

The acetylene results may be helpful in determiningthe role of biogeochemical

reduction. This is a specialtyanalysisthat can be performed by Microseepsor other

qualifiedspecialtylab.

• One to twoevents of biologicalanalysisare recommendedto track potentialincreases

in dehalococcoidespopulationsat MW041101 and MW041102. CENCUS analysisby

MicrobialInsightsis recommended.

• All site monitoringwellswill be sampledfor chlorideanalysistwo times per year. The

chlorideresultsmay helptodeterminethefate of chloridefromthe reductionof TCE.

The above analysisis expected to providesufficientinformationto evaluate biodechlorination

progress. Reliablefield measurementsof pH, ORP, DO, and conductivitywill be sufficientto

definethe reducingconditionsneeded. The followingprocedureis recommendedto obtainthe

mostreliableORP measurements.

• Purgeand samplewellusinga submersiblepumpor peristalticpumpwithcheckvalve.

A bailermaybe neededat someofthe wellsdue limitationsof depthor welldiameter.

• Use a flow-throughcellor a batch-filled,sealedcellwith submergedORP sensor. The

cell shouldbe mixed usinga portablemagneticstirrerunlesssufficientflow is available

for mixing.

2,0 SCOPE AND PROPOSED MONITORING- IN-SlTU SVE TREATMENT

This section presents a summary of the SVE work performed and recommendationsfor

continuedoperationandmonitoringofthe SVE system.

2.1 SVE Pilot:Test

SVE pilot testing was performed in the TCE source area of the Pride Hangar site during

May 2004. The purposeof the SVE testingwas to determineif significantsolventvapor(mass)

existswithinthe vadosezone, warrantinginstallationand operationof an SVE system. Results

of the SVE testingare includedin a memo(Pride Hangar SVE Testing and Recommendation)

preparedby EarthTech,dated May24, 2004.

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EarthTech ATy_oInternatieealLtd.Company

Mr.MarkMailander

U.S.ArmyCorpsofEngineers

February21,2005

Page7

SVE pilottestingwas performedat temporarywells SVE1101, SVE1102, and SVE1103 and at

existingwell MW041101 (see Figure2). The resultsare summarizedbelow:

• Unsaturatedsoil has a low permeabilityto vapor flow as evidenced by the lack of

measurablevacuum observedduring testing at nearby wells and the relativelylow

extractionflowrates.

• Testingat SVE1101 and SVEl103 indicatethat a lowconcentrationof organicvapors

exists up-gradient and approximately 40 feet down-gradient of the former

UST excavationarea.

• Testingat SVE1102 and MW041101 indicatethat significantvaporconcentrationsexist

within the former UST excavation area with sustainedvapor concentrationsabove

100 partspermillion(ppm).

Basedon SVE pilottest results,a temporarySVE systemwas set up and operatedto address

TCE impactedvadosezone soilsat thePrideHangarsite.

2.2 SVE System Construction

A temporarySVE systemwas constructedto remediateTCE contaminationin the vadosezone.

The systemincludedthe installationof five additionalSVE wells (SVE1104 throughSVE1108).

Eachwellwas constructedof 2-inchdiameterPVCwith a 10-footscreenplacedabovethewater

surfaceand a hydratedbentoniteseal abovethe screen. Well locationsare shownon Figures2

and6.

The SVE systemutilizedsix of the eightSVE wells, includingSVE1102 and SVE1104 through

SVE1108. Wells SVE1101 and SVE1103 were not usedbecauseof relativelyloworganicvapor

analyzer(OVA) measurementsobservedduringSVE pilottesting. The sixwellswere connected

to an electrically-powered5-horsepowervacuumpump(blower)via at-grade PVC piping. Soil

vapor extractedfrom the subsurfaceis vented directlyto the atmospherethrougha discharge

stackwhichextends abovethe PrideHangar.

2.3 SVE System Monitoring Results

The SVE systemwas placed intooperationon July 1, 2004, and has operatedon and off as

follows:

• The system was initially operated continuouslyduring July 1, 2004, through

July22, 2004.

• The systemwas then operatedfor a 24-hourperiodonce per week to reduce energy

consumption and to minimize possible adverse effects on the anaerobic

bio-dechlorinationprocess from prolongedsubsurface aeration. The system was

operatedinthismannerfromJuly28 throughNovember4, 2004.

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EarthTech AT_ecoInternationalLtd.Company

Mr.MarkMailander

U.S.ArmyCorpsofEngineers

February21,2005

Page8

• The system was operated continuously during the week of November 8, 2004, to

determine if the rate of TCE removal is high enough for long periods of operation.

• The SVE system has not operated since November 15, 2004.

System monitoring included observing and recording system vacuum pressures and collecting

vapor samples from individual SVE wells and the system effluent. Vapor samples were collected

in Tedlar bags and field screened for VOCs using an OVA. System monitoring data is included

in Table 4.

During the monitoring period, vacuum pressures ranged at the blower and the individual wells

are fairly consistent at 60 inches of water. OVA readings on vapor samples collected from the

SVE wells ranged from 9 parts per million (ppm) in SVE1105 (July 7, 2004) to 500 ppm in

SVE1106 (July 28, 2004). OVA readings on vapor samples collected from the system discharge

stack (effluent) ranged from 10 ppm (November 4, 2004) to 105 ppm (October 21, 2004) with

lower concentrations the longer the system runs in a cycle. OVA readings on effluent vapor

samples were generally less than samples collected from individual SVE wells because

=make-up" air (fresh air) was required by the blower due to high vacuum pressures, i.e., the

vapor stream was diluted. OVA results over the week of continuous operation show a low but

steady removal.

The TCE mass removal rates for the initial operation was estimated at 2.4 Ibs/day for a total of

83 Ibs removed through November 4, 2004. TCE removal over the week-long test in November

isestimated at 0.8 Ibs/day and the total removal to date is approximately 99 Ibs.

2.4 Recommended System Operation

The latest week-long operation event showed a low but steady removal of TCE indicating that

continued SVE operation is warranted. However, due to the potential aeration of ground water

and its detrimental effect on the anaerobic ground water treatment project, it is recommended

that the SVE system is not re-started until further ground water treatment progress is made. The

SVE operation may be delayed until the spring of 2006 and will be evaluated in future status

reports.

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EarthTech

ATycoInternationalLtd.Company

Mr. Mark Mailander

U.S. ArmyCorpsof Engineers

February21,2005

Page 9

2.5 Ambient Monitoring

The followingair samples have been collectedfrom within the Pride Hangar to determine

whetheroperationof the SVE systemis impactingairqualitywithinthe PrideHangar:

• Two samplesin June 2004 before operationof the SVE systemto establishbaseline

levelsinthe PrideHangar.

• Two samplesonOctober6, 2004, afterthe SVE systemwas operatedfor approximately

20 hours.

• Twosampleson November15, 2004, afterthe SVE was operatedfor 17 days.

Each sample was collectedover an 8-hour periodusinga SUMMA®canister and analyzed for

VOCs. A completeset of analyticalresultsforthe Juneand Octobersampleswas providedwith

Serial LetterNos. 1-54-RA-408 and ERS-3-RA-144, respectively.The analyticalresultsfor the

November2004 samplesareattached.

Analyticalresultsare providedon Table 5. The rangeof TCE concentrationsfor each of these

eventsisas follows:

TCE Concentration,

Even...__tt parts per billion by volume (ppbv)

Priorto SVE Operation <0.0075

Afteroperationfor 20 hours 0.14-2.5

After operationfor 17 days 0.053-0.062

While the data is limited,it does suggestthat operationof the SVE systemresultsin increased

TCE air concentrationswithinthe Pride Hangar. VOC concentrationsappearto be higherwhen

the systemis initiallystartedwithdecreasedconcentrationsas the systemoperatesfor a longer

periodof time. Thisis consistentwithhigherconcentrationsinthe SVE systemdischargeduring

the initialperiodof an operatingcycle.

Based on these results,a carbon treatment unit is being added to the SVE system effluent

dischal:geto reduce emissionsof VOCs. Additionalsamplingwithin the Pride Hangar is

recommendedto determinewhetherthe treated SVE vapor dischargehas any impacton air

qualityinthe building.

2 30 009
EarthTech ATycoInternational Ltd.Company

Mr.MarkMaUander

U.S.ArmyCorpsofEngineers

February21,2005

Page10

Recommendedsamplesare as follows:

Time Sample Description Rationale

PriortoSVE One samplewithinthe Pride Provideadditionalbackground

Operationa Hangar. informationwithinthe PrideHangar.

One ambientair sample Determineconcentrationsinambient

upwindofthe SVE system, air, unaffectedby the SVE system.

Beginsampling Two samples(eastandwest Resultsobtainedwithinthe

withinthefirst sides)withinthe PrideHangarinOctoberand

24 hours PrideHangar. November2004 showedhigher

following TCE air concentrationswere observed

startupofthe whentheSVE systemis initiallyturned

SVE system on. Thisresultwouldbe used ifthe

SVE systemwere operatedina =pulse"

modeand providestheworst-case

scenario.

One ambientair sample Determineconcentrationsinambient

upwindofthe SVE system, air,unaffectedby the SVE system.

Afteroperation Two samples(eastand AssessTCE concentrationswith

ofthe SVE westsides)withinthe continuousoperationofthe

systemfor PrideHangar. SVE system.

14 consecutive One ambientair sample Determineconcentrationsinambient

days upwindoftheSVE system, air,unaffectedby theSVE system.

a The SVE systemhas notbeeninoperationsinceNovember15, 2004.

Air quality standards for the Pride Hangar have not been established. Table 5 includes

occupationalstandardsforworkers,as defined inthe Air ForceOccupationalSafetyand Health

(AFOSH) Standard 48-8, Target Indoor Air Concentrationsfor residential use, and the

USEPA RegionIII riskbasedconcentrations(RBCs)for ambientair. Noneis directlyapplicable

sincethe primaryuseforthe PrideHangaris recreationalexerciseand theexposuretimeswould

be differentfromthe exposuretimesusedto developthe standardslisted. Analyticalresultsfor

the recommendedsamples will be reviewed and, if necessary, site-specifictarget indoor air

concentrations_may be calculatedusingconservativeexposurescenariosfor the recreational

users.

2.6 Sample Procedures

The vapor samples will be collectedusing SUMMA® canisters as described in Serial Letter

No. 1-43-RA-386, datedJuly22, 2002. Each samplewillbe a compositesamplecollectedfor a

periodof 8 hours.

Vapor samples will be analyzed by Pace Analytical (Pace), Minneapolis,Minnesota,using

MethodTO-15 SIM for theVOCs listedon Table 6. Reportinglimitsare includedonTable 6 but

thesecanvary dependingontheactualsamplevolumecollectedandwithdilutions.

2 30 o10
EarthTech

ATyco I_ational Ltd.Company

Mr. Mark Mailander

UoS.ArmyCorpsof Engineers

February21,2005

Page 11

Air sample results can be reported in units of ppbv or micrograms per cubic meter (ug/m3). Units

of ug/m°requirea conversionbythe laboratoryandresultswillbe reportedin ppbv. Bothsetsof

unitsare includedon Table6 sinceair sampleshavebeen reportedin unitsof ug/m3 inprevious

submittals.

3.0 PRIDE HANGAR SOURCE TREATMENT STUDY TIMING AND REPORTING

A period of 12 monthsis considerednecessary to evaluate the dechlorinationgroundwater

treatment approachat the Pride Hangar Site. The study results will be summarizedin the

quarterly OU-11 LTM reports and in status reports to be submitted in June and December

of 2005. Additionalstatusmaybe reportedintechnicalmemorandaas necessary.

Completionof thesoilboringsand installationofthefourinjectionand three monitoringwellswill

be scheduledwhentheworkplanis approvedandthe injectionis approvedby EPA.

Sincerely_

KeithJ. ,_lderson, P.E.

ProjectM'anager

Enclosures

file: 74311/01.1503

Tim Pavek

John DeYoe

Jim Haggins

Joane Lineburg

JeffMashburn

BobTodd_

D_NightPochant

Deb Morrissey

Joe Odegaard

Greg Brooks

CathyLarson

L5WORk'3.ERS\7431 I\wr_SERIAL LETTERS_..E:..RS* 3-RA- 158 DOC

230 011
TABLE 1

MW941102 MONITORING RESULTS

PRIDE HANGAR BIO-DECHLORINATION STUDY

ELLSWORTH AFB

Pre-lnject

Field

Measurements Units 1/29/04 3/9104 4/5104 5/5104 6/7104 718/04 8/4/04 912/04 10/4/04 1113/04 12/10104 116105

pH 6.84 6.95 7.21 7.17 6.75 7.32 7.8 7.18 6.96 7.03 7.03 8.11

Conductivity uS 14181 1511 1492 1486 1059 1437 1479 1508 1527 1527 1531 1389

DO m_/L <0.5 <0.5 i

ORP mV -8 -30 -519 -70 -57 0 -26 -90 -179 -62 -23 -15

Lab Analyses '

TCE ug/L 230 250 220 290 300 324 239 208 300 222 282.5 209

cis-l,2-DCE u_/L 7.3 8.4 7.3 6.4 6.3 <10 6.6 7.2 11 6.9 10.2 8.2

trans-l,2-DCE ug/l_ <10 <10 <10 <10 <10 <10 <0.5 <5 <5 <5 <5 <5

Vinyl Chloride u_/L <20 <20 <20 <20 <20 <30 <0.6 <6 <6 <6 <6 <8

DCEfTCE 0.03 0.03 0.03 0.02 0.02 0.00 0.03 0.03 0.04 0.03 0.04 0.04

Ethane n_/L

Ethene n_/L

Methane n_/L

COD mg/L 9.9 3.6 6.9 <20 <20 2.3 <1 5.6 <1 2 1.6 5.8

Sulfate m_/L 360 394 372 372 417 407 495 404 378 420 395

Observations

Color clear clear clear Clear Clear Clear Clear Clear Clear Clear Clear

Free Oil Layer None None None None None None None None None None None

Odor No No No No No No No No No No No

Notes: ND - Not detected

NR - Not reported

L:lWorldERSI7431l_031TechIPrideHangar Source TreatmentIDechlor-results-PHIMW941102 2 _ 3 0 0 1 2
TABLE 2

MW041101 MONITORING RESULTS

PRIDE HANGAR BIO-DECHLORINATION STUDY

ELLSWORTH AFB

Pre-lnJect

Field

Measurements Units 1/291()4 3/9/04 4/5/04 5/5/04 6/7/04 7/8/04 8/4/04 9/2/04 10/4/04 11/3/04 12/10/04 1/6/05

pH

Conductivity uS

DO mg/L

ORP rnV

Lab Analyses

TCE : u_L 16000 16000 41O0 1100 3000 897 1150 734 1205 853 1370 1018

cis-1,2-DCE u_/L <100 <100 <100 <100 <100 <5 18.4 20 156.5 112 90 122

trans-1,2-DCE ug/L <100 <100 <100 <100 <100 <5 <5 <25 <25 <25 <25 <25

VinylChloride ug/L <200 <1000 <200 <200 <200 <30 <6 <30 <30 <30 <30 <30

DCE/TCE 0.02 0.03 0.13 0.13 0.07 0.12

Ethane ng/L

Ethene ng/L

Methane ng/L

COD rng/L 970 130000 78000 17000 13000 10900 10500 8900 9420 9400 7420 7280

Sulfate m_/L 430 290 220 76 160 138 87.9 82.8 82.3 65 49.4 35.7

DHC CelVmL 3.2

Observations

Milky / Cloudy / Milky Milky Milky Milky Milky Milky Clear,

Color white white White White White White White White White

Free Oil Layer None None None None None None None None None

Odor No Yes Yes Yes Yes Yes Yes Yes

Notes: ND - Not detected

NR - Not reported

DHC - Dehalococcoides ethenogenes
TABLE 3 ,

MW041102 MONITORING RESULTS

PRIDE HANGAR BIO-DECHLORINATION STUDY

ELLSWORTH AFB

Pre-lnJect Pre-lnject

Reld

Measurements Unlts 1/6/04 1/29/04 3/9/04 4/5/04 5/5/04 6/7/04 7/8/04 8/4/04! 9/2/04 10/4/04 11/3/04 12/10/04 1/,6/05

pH 7.12 7.1 8.96 7.12 7.24 7.09 7.3 8.96 7.09 8.94 7.07 7.25 7.37

Conductivity uS 1640 2377 2796 3511 3466 3562 3218 3165 3225 3436 2700 3608 3413

DO rng/L _'

ORP mV 514 -534 -31 -55 -143 -161 -132 -152 -140 -242 -136 -143 -91

Lab Analysea

TCE u_/L 19000 15000 12000 7400 11000 28160 26300 22150 27270 14910 7410 1270

cis-l_2-DCE u_L <50 <200 <500 <500 <500 <200 111 <400 710 803 2480 1201

trans-1,2-DCE u_/L <50 <200 <500 <500 <500 <200 <5 <500 <500 <500 <500 <50

VinylChloride ug/L <100 <400 <1000 <1000 <1000 •<600 <6 <600 <500 <600 <600 <50

DCFJ'I-CE 0.00 0.03 0.04 0.33 0.95

Ethane n_/L

Ethene ng/L

Methane n_/L

COD mg/L 14 <20 18 19 26 39.7 42.4 32.2 28.5 40 3.6 2.1

Sulfate rr_/L 1043 1529 2020 2045 2000 1500 1560 1540 1730 1450 2040 2350

DHC Cell/mL 11.5

Observations

Cloudy, Clear, Clear, Clear, Clear, Clear, Clear, Clear, Clear,

Color Clear Clear Grey _rey _rey _rey _rey _lre_/ grey grey grey Clear

Free Oil Layer None None None None None None None None None None None N(_ne

Odor No No No No No No Yes No No Slight Yes Yea

Notes: ND - Not detected

NR - Not reported

DHC - Dehalococooldesethenogenes

.L:_W_r_d.TERC_74311-_3lTechlPrideHangar S_urceTreatment_Dech_r-resu_s-PHVViW_411_2 2 L_ 3 0 014
TABLE4

SVEOPERATIONALMONITORINGRESULTS

PrideHangarSVESystem

EllsworthAlrForceBase

Date Blower Diff, Row Disch, Rnal SVE1104 SVE1105 SVEl106 SVE1102 SVE1107 SVE1108

Vacuum Press, Temp. Effluent h2o/ppm h2o/ppm h2o/ppm h2o/ppm h2o/ppm h2o/ppm

in h2o inh2o 'dm DecjF ppm VAC OVA VIC OVA VIC OVA VIC OVA VAC OVA VAC OVA

7/1/2004 62 2 72,9 325 62 * 70 * 62 * 60 225 50 * 58 45

7/112004 35 * 90 400 225 65 38

7/2/2004 60 2 73,1 154 24 60 * 68 60 60 78 58 100 48 80 58 60

7/6/2004 61 2 73,0 15 61 * 61 21 61 16 60 48 48 60 58 37

7/7/2004 60 2 73,1 18 60 35 60 9 60 40 60 30 48 13 57 20

7/12/2004 61 2 73,0 14 61 45 61 40 61 60 60 120 48 36 58 20

7/22/2004 61 1,9 71,2 18 60 115 58 55 59 114 58 115 45 46 55 45

7/28/2004 60 2,1 74,9 30 42 * 59 * 60 500 59 165 48 95 57 30

7/29/2004 60 2,1 74,9 22 60 130 58 40 59 250 58 130 47 50 57 22

8/6/2004 60 1,9 71,3 20 60 105 60 55 61 250 59 106 48 60 58 30

8/13/2004 59 2,4 80,2 15 59 68 58 55 60 100 58 95 46 60 56 35

8/19/2004 60 2,2 76,7 25 60 * 58 * 59 * 58 250 48 * 57 *

8/20/2004 59 2,4 80,2 23 60 * 59 62 60 200 58 125 47 75 57 46

8/26/2004 60 2,2 76,7 125 59 * 58 * 58 * 57 260 47 * 56 *

8/27/2004 60 2,5 81,8 20 59 100 58 70 59 205 57 55 47 105 55 38

9/2/2004 59 2,1 75,0 20 60 * 58 100 60 300 58 55 49 20 57 90

9/3/2004 59 2,3 78,5 23 59 105 58 85 59 175 57 150 48 75 55 55

9/9/2004 60 2 73,1 60 61 * 61 * 63 * 60 100 50 * 58 150

9/10/2004 60 2 73,1 30 60 * 60 85 61 400 59 150 49 75 58 70

9/16/2004 59 2,3 78,5 56 58 * 57 * 60 * 58 250 47 * 56 *

9/17/2004 59 2,3 78,5 17 58 65 58 75 59 225 58 120 47 70 56 65

9/23/2004 60 2,2 76,7 45 59 * 57 * 0 600 58 120 48 275 56 90

9/24/2004 60 2.2 76,7 30 60 * 59 130 60 310 59 120 48 90 57 90

9/30/2004 60 2,1 74,9 60 60 * 59 * 60 * 58 125 48 260 56 175

10/1/2004 60 2,4 80,1 24 60 130 60 125 61 225 57 90 49 80 58 80

10/5/2004 60 2,1 74,9 60 60 * 59 450 60 * 58 85 48 60 57 100

10/6/2004 60 2,1 74.9 26 60 65 59 80 60 100 58 55 48 75 57 65

10/14/2004 60 2 73,1 80 60 * 58 * 60 * 58 210 48 350 57 200

10/15/2004 60 2,4 80,1 30 59 * 58 130 59 500 57 100 47 125 56 100

10/21/2004 59 2,2 76,8 105 59 400 58 * 55 550 58 70 47 330 56 210

10/22/2004 60 2,2 76,7 30 59 160 58 250 60 300 58 110 48 95 56 100

11/4/2004 60 2,4 80,1 10 60 120 58 150 61 90 58 40 48 N/S 57 10

11/8/2004 60 2,7 85,0 18 58 180 57 120 59 225 57 75 47 50 . 56 36

11/9/2004 60 2,7 85.0 22 58 200 57 150 59 250 57 70 47 45 56 37

11/12/2004 60 2.6 83,4 20 59 200 58 141 59 250 57 50 47 35 56 33

Operating Notes: Blower shut down 7-23-04, operated approx 24 hours 7/28-7/29, 8/5-8/6, 8/12-8/13, 8/19-8/20, 8/26-8/27, 9/2-9/3, 9_-9/10, 9/16-9/17, 9/23-9-24, 9/30-I0/1,10/5-10/6, 10/14-10/15, 10/21-

10/22,10/29-11/15(problemwithFID11/2)

- - Sampleextinguished flameonOVA

I "\Work_ERS_74311\Tech_Prlde Hangar Source Treatment_SVE RALPH SVE 2 l_JL 30 015
TABLE 5

SUMMARY OF DETECTED RESULTS IN AIR SAMPLES

Evaluation of the Pride Hangar SVE System - Event #3

' Ellaworth Air Force Base, South Dakota

EPA Pre-SVE Operation During SVE Operation

OSHA ACGIH AFOSH Target Indoor Air Region III Pride Hangar E Pride Hangar W Pride Hangar E Pride.Hangar E Pride Hangar W Pride Hangar W Trip Blank

Anal_e Units PEL TLV I Standard Concentration" RBC c 6/2/2004 6/'2/2004 10/6/2004 11/15/2004 10/6/2004 11/15/2004 3/15/2004

_arbonTetrachlodde ppbv 10,000 5,000 5_000 0.026 0.019 < 0.0077 < 0.0077 0.1 0.1 0.11 0.055 < 0.066

Chloroform ppbv 50,000= 10_000 10,000 0.022 0.016 < 0.0077 < 0.0077 < 0.0077 < 0.026 < 0.012 < 0.030 < 0.066

Chloromethene ppbv 100,000 60r000 50_000 1.2 4.6 0.034 < 0.0077 < 0.0077 0.37 0.13 0.43 0.16

1,1-Dichloroethane ppbv 100,000 100,000 100,000 120 12.6 < 0.016 < 0.016 <0.016 < 0.055 < 0.025 < 0.063 < 0.14

1_.-Dlchloroethane ppbv 50,000 10rooo 10_000 0.023 0.017 < 0.0077 < 0.026 < 0.012 < 0.030

1,1-Dlchloroethene ppbv none 5,000 5,000 50 5.6 < 0.0077 < 0.0077 < 0.0077 < 0.026 < 0.012 < 0.030 < 0.066

cis-1_2-Dtchloroethena ppbv 200,000 200_000 200,000 8.8 0.935 < 0.0077 < 0.0077 0.026 < 0.026 0.47 < 0.030 < 0.066

bamp1_2-Dk:htoroethene p_ 200,000 200,000 200,000 18 1.8 <0.0077 <0.0077 <0.0077 <0.026 <0.012 <0.030 <0.066

Meth_kmeChk)dda ppbv 26,000 50_000 26,000 1.6 1.1 0.26 0.12 6 0.09

1,1,2r2-Tetrachlornethane ppbv 6_000 lr000 1,000 0.0061 0.005 < 0.0077 <0.0077 <0.0077 <0.026 <0.012 <0.030 <0.066

Tetraddoroethene ppbv 100,000 26r000 25,000 0.12 0.046 < 0.0077 < 0.0077 < 0.0077 0.048 0.2 < 0.030 < 0.066

1,l_l-Trlcldoroethane ppbv 350,000 350_000 350,000 400 42.2 < 0.0076 < 0.0075 < 0.0076 < 0.026 < 0:012 < 0.029 < 0.064

1,lr2-Tdchloroethane ppbv 10,000 10,000 10,000 0.028 0.020 < 0.0077 < 0.0077 < 0.0077 < 0.026 < 0.012 < 0.030 < 0.066

Trlchloroethene ppbv 100_000 50,000 50,000 0.0041 0.003 < 0.0075 < 0.0076 0.14 0.053 2.5 0.062 < 0.064

VinylChlodde ppbv 1,000 1,000 1,000 0.11 0.028 <0.0075 <0.0076 < 0.0075 <0.026 <0.012 <0.029 < 0.064

' and Health Administration's(OSHA) permissible exposure limits (PELs).

ACGIH TLV - Amedcan Conference of Industrial Hygienists' (ACGIH) threshold limitvalue (TLV).

AFOSH - Air Force Occupational Safety and Health (AFOSH) Standard 48-8.

• - Draft Guidance for Evaluating the Vapor Intrusionto IndoorAir Pathway from Ground Water and Soils. Nov. 2002. The values shown are for a cancer risk level of 1E-6 and a hazard quotient of 1 for non-cancer risk.

- Exposure shall at no time exceed the exposure limit given. If instantaneous monitoring is notfeasible, then the ceiling shell be assessed as a 15-minute time weighted average exposure which shell not be exceeded at any time duringthe

woddng day.

o. RBC - Risk-based concentration (U.S. EPA, October 8, 2004). RBCs for noncorcinogens divided by 10 to accountfor potential additive affects. RBCs converted from unitsof ug/m3 to ppbv uelng the equation: ((Value inug/m3)Imolecular

walght)*24.486.

- - Not analyzed

L:lWorldTERC174311_O3tTechtPrkleHangattData . Pride HangarSVE event3 Rev_opbv 2/21/2005

2,130 OJ6
,D

TABLE 6

LIST OF VOCS FOR PRIDE HANGARAIR STUDY

EIIsworth Air Force Base,South Dakota

Reporting Target Indoor EPA Reporting Target Indoor EPA J

Limit Air Concentration Region III Limit Air Concentration Region III

Analyte (ug/m3)a (ug/m3) b (ug/m3)c (PPbv)a (ppbv)b (ppbv)C

Carbon tetrachloride , 0.0333 0.16 0.12 0.0052 0.026 0.019

Chloroform 0.0258 0.11 0.077 0.0052 0.022 0.016

Chloromethane 0.019 2.4 9.5 0.0052 1.2 4.6

1,1-Dichloroethane 0.0453 500 51 0.011 120 12.6

1i1-Dichloroethene 0.021 200 22 0.0052 50 5.6

cis-1,2-Dichloroethene 0.021 35 3.7 0.0052 8.8 0.935

trans-1,2-Dichloroethene 0.021 70 7.3 0.0052 18 1.8

1,1,2,2-Tetrachloroethane 0.0363 0.042 0.031 0.0052 0.0061 0.005

Tetrachloroethene (PCE) 0.0359 0.81 0.31 0.0052 0.12 0.046

1,1t1-Trichloroethane 0.0283 2200 230 0.0051 400 42.2

1,1,2-Trichoroethane 0.0288 0.15 0.11 0.0052 0.028 0.02

Trichloroethene (TCE) 0.0279 0.022 0.016 0.0051 0.0041 0.003

Vinyl Chloride 0.0133 0.28 0.072 0,0051 0.11 0.028

a. The reporting limitfor each sample and compound will vary based on the amount of the time weighted sample taken and if there was

a dilution performed on the sample.

b. Draft Guidance for Evaluating the Vapor Intrusion to Indoor Air Pathway from Ground Water and Soils. November 2002. Lower

value of the cancer riskat 1E-6 or a hazard quotient of 1 for non-cancer risk.

c. RBC - Risk-based concentration (U.S. EPA, October 8, 2004). RBCs for noncorcinogens divided by 10 to account for potential

additive effects. RBCs converted from units of ug/m3 to ppbv usingthe equation: ((Value in ug/m3)/molecular weight)*24.486.

L:lWorklERSI7431l_031TechIPndeHangarIReportingLimitsVapor-PrideHangarSVE 2 i_ 3 0 0 1 ?
DATE -Mon Feb 21 10:31:48 2005

"'." " ',...% .... : \',,_ _r'

1

. ,,.".."

".:-"...,. ",-,,:.... _'-_, _!,, ,,._/" ,- //...._,,:'. ,, ,",.,_, ; "...,._:,_, .'

,,\ ..%.

....... O " " ,*" ...... ", 3"_-,7;'"" "_"< _"*"_ ',

• \"_"--.__._Y , "'"// ,'" \ ".,."x, "\., ,,i "........ ..."_,_.,.

" .,.. ,.... ,.._.,,_.,x,_ -'" ",._:_ i

• ." "; ' " ". " I " _" ,";"""_,_ "J

• _ ,, \ , \, ".... ,_..:, ,.._,;._,,"

• .,.j'"_('_, . , .,",/:" .,_, -\.. •...... _.. ," • ,_,,

_. ,_. ! t ,_ _:_ I D :..:C ",::_ ,,,Y" .

",, .,,,,"" \, ) /" /

/ / "' _" _ " ' "_"x.

" 1%3 " "-- .'_ " I

,. Cl_ t

I_Ox_,,, * "-- .'" • I/I

,,, , ._:,, ..:,".,. : ..-,_%,., PRIDE HANGAR - , " ""'<"

"% .,,, _ .., ) .,' ',,.

",, Z;',,

N,

•.x,..,,,, ,_" <."_

.. ._...,,,->." ,.,

LEGEND - .... '----" ....... , -* "_o-" ,,A

LTO/LTM GROUNDWATER ... - '_' '-b MONITORING LOCATION • _.. ...... _

EXTRACTION WELL ",,, . ... ",...

,_._. "• _. .,,, _ ""-_. ",, .,

DCE I CHLOROETHENE "_..._%, ------ ", ""--

TCE TRICHLOROETHENE 1

CONTOURLINES BASEDON" PRIDE HANGAR

EXTRACTIONWELLSSAMPLEDOCTOBER2001, SAMPLING LOCATIONS/ORGANIC CONCENTRATIONS

DIRECT PUSH LOCATIONSSAMPLEDJANUARYAND LTO/LTM APRIL 2004 EVENT OU'I!

APRIL 2002, AND MONITORINGWELLSSAMPLED ELLSWORTHAFB, SOUTH DAKOTA
DATE -Mon Feb 21 10:31,44 2005

DGN -\\usminsOl 1 \dotoFI \work\terc\63842I '_ 54\Icodd\PRIDE IIII \aIIII w_flow.d II / I Ian/ III I[ I I I I I II II I IIII

, , ,, ,,,, _ toc=

%" / J / • i / "\,

\. ",, ,, '_,_._ ,- ," "- MW941102 22.T :3216.14 3193,44

•\ , _3%_>'0¢o_ " ,-

"_ • / / s

\".,,_4- .......... , ,," ,-'" ,-" MW041101 2,2.9 3215. 81 3192. 91

\ ,_,_.{ ,_,._,, PARKI NG ,

",,.\_,,, .... \ ,'" ..... .,, ,'" 1_041102 23,25 3215.98 3192.73

,,_ ..,. ,-" -,. ,'"

/ /\ s

"\'N, .,.. ,• • /

•._ ",,"X _: ," 2" • . -

',._-.p=

",_'/,SVE1101-- ..... ,,, 105

""..\, 1106

OILAREAINJECTIONHYDRANT. DPO2PHOI(sEE NOTE1oT1 ) PRIDE HANGAR--__

SVE1104 SVE1108

MW041101 MW041102

3192.91 3192.73

SVE1102

UST EXCAVATI ON \ \

" \ O' 10' 20'

_3./ "'"", SCALE

/ I_1I_tLII ILIIlk \,.\ NOTE:

SVE11\. "-\1. 30,590 ug/I TCE DETECTED IN

EXISTING MONITORING MW94t102 \, "....GROUNDWATER SAMPLE COLLECTED

_C_ WELL LOCATION 3193.44 ", \" FROM DIRECT PUSH SOIL BORING (2002).

(_ FORMER DIRECT PUSH ' ' ' ' ' ' '"" "' ' ' SOl L BORI NG LOCATION FIGURE2

GW FLOW 3/9/04

• SVE PILOT TEST WELL LOCATION PRIDE HANGAR SITE

C) SVE WELL LOCATIONS ELLSWORTH AFB, SOUTH DAKOTA PREPARED FOR U.S. ARMY CORPS OF_ENGINEERS _ I II I IIIII III I I I I IIII

¢

30 019
Figure 3

MV¢941102 Dechlorinization Results

600 50

500 -50

400 -150

300 -250

o _

200 -350

M

o

I00 -450

g i

0 , -- 'r _ '," , _ t' _ , , • r T , T ,, T -550

1/29/04 2/28/04 3/29/04 4/28/04 5/28/04 6/27/04 7/27/04 8/26/04 9/25/04 10/25/04 11/24/04 12/24/04

Date, mm/dd/yy

['-O'-TCE "I-cis.I,2-DCE • -VinylChlorid¢ -it-SO4 --_--ORP]

2 30 020
Figure 4

MW041101 Dechlorinization Results

18000 500

16000 450

400

14000

350 !

12000 _

3oo

•_ 10000 i

250

o 8000

_ 200

6o0o

150 _"

4000 100

2000 50

0 ._ -N.- _ m- t _ i .Hi-- _, 'r m ._t,-- v _ l _" 't _' i _ 0

1/29104 2/28104 3129/04 4/28/04 5/28/04 6/27/04 7/27/04 8/26/04 9/25/04 10/25104 11/24104 12/24/04

Date, mm/dd/yy

I-'*--TCE -"ll-eis-l,2-DCE -* - Vinyl Chloride -Ig--SO4 1

2430 021
Figure 5

MW041102 Dechlorinization Results

30000 2900

2400

25000

1900 _

_" 20000 1400 _,

900

oooo

5000 M- -I00 _

0 , , -600

116104 2/5/04 316104 415104 515104 6/4/04 714104 8/3/04 9/2/04 10/2/04 1111/04 12/1/04 12/31104

Date, mm/dd/yy

I-'-TCE"-I-cis-I,2-DCE _ORP _ Vinyl Chloride -')_ Sulfate [

2{30 022
DATE -Mon Feb 21 10:31:36 2005

MW041101 141102

SVE1102 ....

"% -.._.

LEGEND . ", ,

_) EXISTING MONITORING "\ ",,,_p. ",, .,,, O' 10' 20' WELL LOCAT! ON SVE_,103 ,.

, \ SCALE

(_ FORMER DIRECT PUSH \ "

S01L BORING LOCATION " ""

SVE PI LOT TEST WELL LOCATI ON(_) MW941102 .....,.,, "\

"\. _.._ o. "%

C) SVE WELL LOCATIONS ". , A.,,,'_ , " ,, ,, ................

FIGURE 6

PROPOSEDGROUNDWATERINJECTION WELL PROPOSED GROUNDWATER INJECTION

PROPOSED MONITORIN6 WELL AND MONITORING LOCATIONS PRIDE HANGAR SITE

ELLSWORTH AFB, SOUTH DAKOTA

PREPARED FOR__U.S. ARMY_CORPS OF__ENGINEERS

2,'.30 023
1700Elm$treeL Suite200

Mi_, MN 55414

Phone: Fax:(612)607-6444 607-1700

December 02, 2004

Ms. Cathy Larson

Earth Tech

3033 Campus Drive N

Plymouth, MN 55441

RE: Project: 103214

ProjectID: EAFB ERS 74311.01.1504

Dear Ms. Larson:

Enclosedare the analyticalresultsfor sample(s) received bythe laboratoryon November 16,

2004. Resultsreportedherein conformto the most currentNELAC standards,where

applicable, unlessotherwisenarratedin the bodyof the report.

Ifyou have any questionsconcerningthis report,pleasefeelfree to contactme.

Sincerely,

Daryl Peterson

Daryl.Peterson@pacelabs.com

IHinois Certification #: 200011

Minnesota Certification #: 027-053-137

W'sconsin CerUficalJon#: 9999407970

Enclosures

-T

• Page I o1"10

REPORTOF I.ABORATORYANALYSIS

Tldsmlx_ =dwllno(be_mduced, exceptInful,

vdthouthe_ltlmncocse_ (:4PaceAnalyticalSe_ces. Inc.

2,130 024
"_eAnalytical, "_"*'_""'_"®_"*"",--'_

f Www._s.com MInn_, MN 55414

Phone:(612)607-1700

Fax:(612)607-6444

SAMPLE SUMMARY

Project: 103214

Project ID: EAFB ER$ 74311.01.1504

Lab ID Sample ID Matrix Date Collected Date Received

103214001 S36-PRIDEHANGAR-W Air 11/15/04 15:05 11/16/04 09:30

103214002 135-PRIDEHANGAR-tE Air 11/15/04 15:05 11116/04 09:30

Page 2 of 10

REPORT OF LABORATORY ANALYSIS

This mpod _mll ,or be _, exceptinfull,

wilhoutthewdllmnconse_ofI=_e/_nalyUcMServices,Inc.

2/',30 025
"_eAnalytical

° e Pace/_JudytJcal Services,Inc.

1700 Elm Stree_ Sure 200

www.pace/abs;com Minneapolis,MN 55414

Phone: Fax:(612)607 (612)607-6444 -1700

SAMPLE ANALYTE COUNT

Project: 103214

Project IO: EAFB ERS 74311.01.1504

_a_tes

Lab ID Sample ID Method Reported

103214001 636-PRIDEHANGAR-W TO-15 by SIM 15

103214002 135.PRIDEHANGAR-E TO-15 by SIM 15

-7

Page 3of 10

REPORT OF LABORATORY ANALYSIS

Thls mpofl shsl no/be reproduced,exce_ In_I,

_U_ut lhe wn_en consent of Psce Analy_c_ Servkm, Inc.

__:_ 2 43 0 0 26
_ n_ll/_//._/ 1700ElmStreet S. 200

_, MN 55414

f www._bs.com Phone: Fax.(612)607-1700 (612)607-6444

ANALYTICAL RESULTS

Project: 103214

Project ID: EAFB ERS 74311.01.1504

Solid results are repotted on a dry weight basis.

Lab ID: 103214001 Date Collected: 11115/04 15:05 Matdx: Air

Sample IO: 636.PRIDEHANGAR-W Date Received: 11/16/04 09:30

Parameters Results Units Report _ DF Prepared By Analyzed By CAS No. Qual RagLmt

Air

TO15 MSV AIR SIM Analytical Method: TO-15 by SIM

Carbon telrachlodde 0.055 ppbv 0.030 5.73 11/30/04 22:59 MTG 56-23-5

Chlorofomt ND ppbv 0.030 5.73 11/30/0422:59 MTG 67-66-3

Chloromethane 0.43 ppbv 0.030 5.73 11/30/04 22:59 MTG 74-87-3

1,1-Dichloroethane ND ppbv 0.063 5.73 11/30/04 22:59 MTG 75-34-3

1,2-Dichloroelhane ND ppbv 0.030 5.73 11/30/04 22:59 MTG 107-06-2

1,1-Dichkxoethene ND ppbv 0.030 5.73 11/30/04 22:59 MTG 75-354

ds-l,2_ ND ppbv 0.030 5.73 11/30/04 22:59 MTG 156-59-2

tmns-l,2-Dichioroethene ND ppbv 0.030 5.73 11/30/04 22:59 MTG 156-60-5

Methylene chloride 0.090 ppbv 0.086 5.73 11/30/04 22:59 MTG 75-09-2

1,1,2,2-Telnchloroethane ND ppbv 0.030 5.73 11/30/04 22:59 MTG 79-34-5

Teb-addoroethene ND ppbv 0.030 5.73 11/30/04 22:59 MTG 1"_7-18-4

1,1,l-Trtchloroelhane ND ppbv 0.029 5.73 11/30/0422:59 MTG 71-55-6

1,1,2-T_thane ND ppbv 0.030 5.73 11/30/0422:59 MTG 79-00-5

T_ 0.062 ppbv 0.029 5.73 11/30/04 22:59 MTG 79-01-6

Vinyt c_lodde ND ppbv 0.029 5.73 11/30/04 22:59 MTG 75-01_I

Date: 12/02/2004 Page 4 of 10

REPORTOF LABORATORYANALYSIS

Thismpod shal not be relxodcced,exert infull,

WglX_ I_ _iaen oor_nt ofF_e Analyl_ _M_. Inc..

2,'.3 0 027
1700ElmStreet,Suite200

Minn--, MN 55414

Phone:(612)607-1700

Fax:(612)607.6444

ANALYTICAL RESULTS

Project: 103214

Project ID: EAFB ERS 74311.01.1504

Solid results are reported on a dry weight basis.

Lab ID: 103214002 Date Collected: 11/15/04 15.O5 Malrix: Air

Sample ID: 135-PRIDEHANGAR-E Date Received: 11/16/04 09:30

Parameters Results Units Report Limit DF Prepared By Analyzed By CAS No. Qual RegLmt

lUr

TO15 MSV AIR SIM Analytical Method: TO-15 by SIM

Carbon te(rachlodde 0.10 ppbv 0.026 5.04 11/30/04 22:02 MTG 56-23-5

Chlorofom_ ND ppbv 0.026 5.04 11/30/0422:02 MTG 67-66-3

Cldorome(hane 0.37 ppbv 0.026 5.04 11/30/0422:02 MTG 74-87-3

1,1-Diddmoelhane ND ppbv 0.055 5.04 11/30/0422:02 MTG 75-34-3

1_._lhane ND ppbv 0.026 5.04 11/30/0422:02 MTG 107-06-2

1,1-Dichkxoelhene NO ppbv 0.026 5.04 11/30/0422:02 MTG 75-35-4

cts-l,2_ ND ppbv 0.026 5.04 11/30/04 22:02 MTG 156-59-2

trans-l_-Dichlon_thene NO ppbv 0.026 5.04 11/30/0422:02 MTG 156-60-5

Methylene chloride 0.12 ppbv 0.076 5.04 11/30/04 22:02 MTG 75-09-2

1,1,2,2-Telraddoroethane NO ppbv 0.026 5.04 11/30/0422:02 MTG 79-34-5

Telrachkxoethene 0.048 ppbv 0.026 5.04 11/30/04 22:02 MTG 127-18-4

1,1,1-Trichloroethane ND ppbv 0.026 5.04 11/30/0422:02 MTG 71-55-6

1,1,2.Tdchloroethane ND pflbv 0.026 5.04 11/30/0422:02 MTG 79-00-5

T_ 0.053 ppbv 0.026 5.04 11/30/0422:02 MTG 79-01-6

Vinyl ¢hlodde ND ppbv 0.026 5.04 11/30/04 22:02 MTG 75-01-4

Date: 12/02/2004 Page 5 of 10

REPORTOF LABORATORYANALYSIS

11_s_xxt shal notbe_duced, e.¢_ _ lul,

wlthouthewflltencoesentofPaceAn_ Servlces.Inc..

028
1700ElmStreet,Sulle200

f wWw._.com Minneapolis, MN 55414

Phone:(612)607-1700

Fax:(612)607-6444

ANALYTICAL RESULTSQUALIFIERS

Project: 103214

ProjectID: EAFBERS 74311.01.1504

PARAMETERQUAUFIERS

DF - DilutionFactor,if reported,representsthefactor

ND - Nc4Detectedatoraboveadjustedreportinglimit,appliedto therepodeddatacluetochangesinsample

preparation,dilutionofthesamplealiquot,or .moi'sturecontenL

J - EsC"natedconcentmlionabovetheadjustedmethodclelectionlimitandbelowtheadjustedreportinglimit.

MDL- AdjustedMethodDetecti_ I_k_.

S - Surrogate

Date:12/02/2004 Page6 of 10

REPORTOF LABORATORYANALYSIS

Thlsmpodshal notbempc0duced, e.ceptInful,

wlthoutlhe_K1mnconsentofPaceAMlytk_Se_omsInc. ,

2 30 029
Pace A.alyffcd Serdcu, Inc.

• O 1700Bm Street,Suite200

Minnea_, MN 55414

Phone:(612)607-1700

Fax:(612)607.-6444

QUALITY CONTROL DATA

Project: 103214

Project ID: EAFB ERS 74311.01.1504

QC Batch: AIR/1277 Analysis Method: T0-15 by SIM

QC Batch Method: TO-15 by SIM Analysis Description: TO-15 GCJMSV AIR SIM

Associated Lab Samples: 103214001 103214002

METHOD BLANK: 28151

Associated Lab Samples: 103214001 103214002

Blank Reporting

Parameter Units Result Umlt Qualifmm

Carbon tetrad_odde ppbv ND 0.0052

Chloroform ppbv ND 0.0052

Chloromatharm ppbv ND 0.0052

1,1-Dichloroelhane ppbv ND 0.011

1,2-Dichloroelhane ppbv ND 0.0052

1,l-Dichloloelhene ppbv ND 0.0052

cts-1,2-DiddoroeS_me ppbv ND 0.0052

tmr-,=,-1,2-Dichloroathene ppbv NO 0.0052

Methylene chloride ppbv ND 0.015

1,1,2,2-'rebaddoroathane ppbv ND 0.0052

Tebaddoroathel_ ppbv ND 0.0052

1,1,1-Tdchloroethane ppbv ND 0.0051

1,1,2-T_lhane ppbv NO 0.0052

Tdchloroethene ppbv ND 0.0051

Vinyl chlodde ppbv ND 0.0051

LABORATORY CONTROL SAMPLE: 28152

Spike LCS LCS % Rec

Parameter Units Conc. Result % Rec Limits Qualifiers

Carbon te_ ppbv 0.11 0.13 118 70-130

Chloroform ppbv 0.11 0.11 103 70-130

Chloromathane ppbv 0.1 0.12 118 70-130

1,1-Dichkxoelhane ppbv 0.1 0.12 114 70-130

1,2_ ppbv 0.11 0.11 106 70-130

1,1-Diddoroathene ppbv 0.11 0.12 112 70-130

ds-l,2-Dichloroethene __ ppbv 0.11 0.11 104 70-130

trans-1,2-Diddomethene" ppbv 0.1 O.10 102 70-130

Methylene chloride ppbv 0.11 0.12 116 70.130

1,1,2,2-T_ ppbv 0.1 0.094 90 70-130

Tatnchlomelhene ppbv 0.1 0.10 98 70-130

1,1,1-Trichloroathane ppbv 0.1 0.13 124 70-130

1,1,2-Triddoroathane ppbv 0.1 0.096 92 70-130

Trichkxoeqhene ppbv 0.1 0.10 101 70-130

Vinylchl0dde ppbv 0.1 0.13 127 70-130

Date: 12/02/2004 Page 7 of 10

REPORT OF LABORATORY ANALYSIS

This mp_ shall no1be reproduced,excel_ Jnful,

wRhouthewdU_ conNnl ofPaceAnalyticalSen4ces.Inc..

2,130 030
1700ElmStreet,Su_ 200

Minneapolis. MN 55414

Phone:(612)607-1700

Fax:(612)607-6444

QUALITY CONTROL DATA

Project: 103214

ProjectID: EAFBERS74311.01.1504

SAMPLEDUPUCATE: 28153 - -

103214001 DUP Max

Parameter units Result Result RPD RPD Quarters

Carbontetrachloride ppbv 0.055 0.057 3 30

Chloroform ppbv ND ND 30 1

Chloromethane ppbv 0.43 0.43 1 30

1,1-Diddoroethane ppbv NO ND 30 1

1,2-_thane ppbv NO ND 30 1

1,1-Dichloroethene ppbv ND NO 30 1

cis-l,2_ ppbv ND ND 30 1

tmns-l,2-1Ycldoroethene ppbv ND ND 30 1

Methylenechloride ppbv 0.090 .0.094 4 30

1,1,2,2-Te_ ppbv ND ND 30 1

T_ ppbv ND ND 30 1

1,1,1-T_thane ppbv ND ND 30 1

1,1,2-Trichloroethane ppbv ND ND 30 1

Tdchloroethene ppbv 0.062 0.062 0.4 30

Vinylchloride ppbv NO ND 30 1

Date:12/02/2004 Page8 of 10

REPORT OF LABORATORY ANALYSIS

Thk mpodsha=mXbereproduced, e==e__ U,

wmhouthet wflttee¢omeetofPaceAnalylk=lSen_, Inc..

2130 031
1700ElmStme_Suite200

www.pac_.com Minneapolis.MN 55414

Phone:(612)607-1700

Fax:(612)607-6444

QUALITY CONTROL DATA QUALIFIERS

Project: 103214

Project ID: EAFB ERS 74311.01.1504

QUALITY CONTROL PARAMETER QUALIFIERS

Consistent with EPA guidelines, umounded data are displeyed and have been used to calculate % recovery

and RPD values.

LCS(D) - Laboratory Control Sample (Duplicate)

MS(D) - Matrix Spike (Duplicate) " "

DUP- Samite Du_icate

RPD - Relative Percent Difference

ND - Not Detected at or above adjusted reporting limit.

J - Estimated concerdmtionabove the adjusted method

MDL- Adjusted Method Detection Limit. detecUon limit and below the adjusted reporting limit.

S - Surrogate

QUALITY CONTROL ANALYTE QUAMRERS

[1] The sample and duplicate results for this paramet_ are less than the reporting limit._ RPD can not be calculated.

-7

Date; 12/02/2004 Page 9 of 10

REPORT OF LABORATORY ANALYSIS

Thisreportshal notbemt:_duced,e_op4 rnful.

witho,tUlewrm_ _nsent of Pa_ Anolytk_ .Se_cm_In_

.t_. • • 5,

'30 032
1700 ElmStreet,Suite2O0

Minneapolis,MN 55414

Phone:(612)607-1700

Fax:(612)607-6444

QUALITYCONTROLDATACROSSREFERENCETABLE

Project: 103214

Project ID: EAFB ERS 74311.01.1504

An_t_

Lab ID Sample ID QC Batch Method QC Batch Analytical Method Batch

103214001 636-PRIDEHANGAR-W TO-15 by SIM AIR/1277

103214002 135-PRIOEHANGAR-E TO-15 by $1M AIR/1277

Date: 12/02/2004 Page 10 of 10

REPORTOF LABORATORYANALYSIS

wilhoutthe_tlon ¢ommrltof PaceAnalylcalSen4oel.k¢,.

,e_. 2,: 30 0 33
PIce A_wlyticalSendces,Inc.

1700ElmStreet

MinneapolisMN, 55414

Phone:612.607.1700

m.pacelabs.com Fax:612.607.6444

Client: Earth Tech Lab Project Number: 103214

Phone: 919-854-6239 Project Name: EAPB ERS 74311.01.1504

Lab Sample No: 101 2 ProjSampleNum: 103214002 Date Collected: 11/15/04 15:05

Client Sample i-PRIDEHANGAR-E Matrix: Air Date Received: 11/16/04 9:30

Parameters Results Units Report Limit Analyzed CASNo. Ftnote

Air

TO-l!

1-Trichloroethane ND ug/m3 0.14 11/30/04 22:02 MTG 71-55-6

2-Tetrachloroethane ND uglm3 0.18 11130/04 22:02 MTG 79-34-5

1,1,2-Trichloroethane ND uglm3 0.14 11130104 22:02 MTG 79-00-5

l,l-Dichloroethane ND ug/m3 0.23 11/30/04 22:02 MTG 75-34-3

l,l-Dichloroethene ND ug/m3 0.I 11130104 22:02 MTG 75-35-4

1,2-Dichloroethane ND uglm3 0.11 11130/04 22:02 MTG 107-06-2

Carbon tetrachloride 0.64 ug/m3 0.17 11/30/04 22:02 MTG 56-23-5

Chloroform ND ug/m3 0.13 11130104 22:02 MTG 67-66-3

Chloromethane 0.777 ug/m3 0.055 11130/04 22:02 MTG 74-87-3

cis-l,2-Dichloroethene ND ug/m3 0.1 11130/04 22:02 MTG 156-59-2 -

Methylene chloride 0.424 uglm3 0.27 11130104 22:02 MTG 75-09-2

Tetrachloroethene 0.331 ug/m3 0.18 11/30/04 22:02 MTG 127-18-4

trans-l,2-Dichloroethene ND ug/m3 0.1 11/30/04 22:02 MTG 156-60-5

Trichloroethene 0.29 ug/m3 0.14 11/30104 22:02 MTG 79-01-6

Vinyl chloride ND ug/m3 0.068 11130104 22:02 MTG 75-01-4

DISCLAIMER: These results have been converted to the units shown from the original

units of measurement assuming 20 degrees Celsius and 1 atmosphere pressure.

Values were not rounded according to EPA rounding rules. THC is quantitated

based on the average response factors of several compounds; the nominal molecular

weight of THC used for units conversion is the average of the moleculan weights of

the compounds used for quantitation.

SUPPLEMENTAL REPORT

_t®::2/2/2oo_ Ur_CorlversionRequest P_ 2

REPORTOFLABORATORY ANALYSISThisreportshagnotbereproduced,exceptinfull,

2430 034
PaceAnalyticalSendces,Inc.

1700ElmStreet

" " "[®/I"1_.._1 Minneapolis,MN 55414

.x..v..,.- Phone:612.607.1700

m.pacelabs.com Far 612.607.6444

Client: Earth Tech Lab Project Number: 103214

Phone: 919-854-6239 Project Name: EAFB ERS 74311.01.1504

Lab Sample No: 10 L ProjSampleNum: 103214001 Date Collected: 11/15/04 15:05

Client Sample ID: Matrix: Air Date Received: 11/16/04 9:30

Parameters Results Units Report Limit Analyzed CAS No. Ftnote

Air

TO-I!

1-Trichloroethane ND ug/m3 0.16 11/30/04 22:59 MTG 71-55-6

2-Tetrachloroethane ND ug/m3 0.21 11/30/04 22:59 MTG 79-34-5

1,102-Trlchloroethane ND ug/m3 0.17 11/30/04 22:59 MTG 79-00-5

l,l-Dichloroethane ND ug/m3 0.26 11/30/04 22:59 MTG 75-34-3

1,1-Dichloroethene ND ug/m3 0.12 11/30/04 22 :59 MTG 75-35-4

1,2-Dichloroethane ND ug/m3 0.12 11/30/04 22:59 MTG 107-06-2

Carbon tetrachloride 0.352 ug/m3 0.19 11/30/04 22:59 MTG 56-23-5

Chloroform ND ug/m3 0.15 11/30/04 22:59 MTG 67-66-3

Chloromethane 0.903 ug/m3 0.063 11/30/04 22:59 MTG 74-87-3

cis-l, 2-Dlchloroethene ND ug/m3 0.12 11/30/04 22 :59 MTG 156-59-2 -

Methylene chloride 0.318 ug/m3 0.3 11/30/04 22:59 MTG 75-09-2

Tetrachloroethene ND ug/m3 0.21 11/30/04 22:59 MTG 127-18-4

trans-l,2-Dichloroethene ND ug/m3 0.12 11"/30/04 22:59 MTG 156-60-5

Trichloroethene 0.339 ug/m3 0.16 11/30/04 22:59 MTG 79-01-6

Vinyl chloride ND ug/m3 0.075 11/30/04 22:59 MTG 75-01-4

b

DISCLAIMER: These results have been converted to theunits shown from the original

units of measurement assuming 20 degrees Celsius and 1 atmosphere pressure.

Values were not rounded according to EPA rounding rules. THC is quantltated

based on the average response factors of several compounds; the nominal molecular

weight of THC used for units conversion is the average of the mo!ecula_ weights of

the compounds used for quantitation.

-7

SUPPLEMENTAL REPORT

_.t.: ,_12/2oo, UnitsConverr_Requ_t P,,_,1

REPORTOFLABORATORY ANALYSISThisreportshallnotbereproduced, exceptinfull, without thettenconsofPace hnalyl Senic/Inc ks,. 2 30 035

• _,_Acco,o •

.o_ ,_

Annotated Comments

Pride Hangar Source Area Treatment Draft Work Plan.

Serial Letter ERS-3-RA-149, dated 21 December 2004

South Dakota Department of Environment and Natural Resources

1. Page 2, Section 1.1 Treatment Status, second paragraph, last sentence: Add a

sentence to note that detection limits for vinyl chloride have been high (100-1,000 ppb)

in many of the samples.

Response: Agreed. This revision has been made.

2. Page 4, Section 1.2 Recommended Electron Donor Injection:

A. First paragraph, first bullet: The Draft Explanation of Significant Differences

should also be edited to include a provision for sodium lactate injection. Edit text as

appropriate.

Response: Agreed. This revision has been made.

B. First paragraph, first bullet, second sentence: Please send me a copy of this

letter.

Response: The letter has not been sent to EPA yet. It will be submitted upon final

approval of this work plan.

C. First paragraph, second bullet: Add text to specify the number of weeks

proposed for sodium lactate injection.

Response: Text has been added to clarify the proposed period of injection.

3. Page 5, Section 1.3 Recommended Monitoring Scope and Procedures:

A. First paragraph, first bullet, first sentence: "Four injection/monitoring wells

__arreecommended east west and south of MW041102 to be used for injection of

" the sodium lactate solution."

Response: Agreed. This revision has been made.

B. First paragraph, second bullet: Would it be possible to install a third monitoring

well northeast of MW041101 to monitor the down-gradient impacts of the original

soy oil injection? Another option would be to move one of the proposed new wells

about 20 feet northwest.

Annotated Comments from SD DENR

Pride Hangar Area Treatment Work Plan 1 18 February 2005

2,'.30 037
Response: Agreed. This revision has been made.

C. Third paragraph, first sentence: Dissolved oxygen concentrations should also

be measured at each monitoring well. Edit text as appropriate.

Response: As agreed during the RPM discussion on January 25, the work plan includes

annual field measurement of DO.

D. Third paragraph, last sentence: During review of recent reports, I've noted

that the detection limits for vinyl chloride at the on-site lab are often 10 ug/L,

while detection limits for other chemicals are 1 or 2 ug/L. Given that vinyl

chloride is an important daughter product of TCE dechlorination, it is important

that the on-site lab be capable of consistently detecting it at concentrations at or

below the Ground Water Quality Standard of 2 ug/L. Please provide assurances

that the on-site lab can meet this criterion except under situations where it is

necessary to dilute high-concentration samples.

Response: We plan to continue the use of the on-site lab for this work, since petroleum

interferences are not an issue at this site. We are evaluating the detection limit for vinyl

chloride this month in an effort to improve the detection limit. However, a slightly

higher detection limit for vinyl chloride is not a major concern because the Pride

Hangar treatment area is distant from the installation boundary.

4. Page 6, Section 1.3 Recommended Monitoring Scope and Procedures:

A. First paragraph, first bullet, first sentence: I recommend dissolved gas

analyses also be conducted on samples from MW941102 and the two new wells.

I also recommend that samples be analyzed for these parameters prior to

injection to establish baseline conditions. Edit text as appropriate.

Response: As agreed during the RPM discussion on January 25, the work plan includes

annual analysis for dissolved gases at the other monitor wells.

B. First paragraph, first bullet, second and third sentences: Since chloride ions

are reportedly released during abiotic reduction of chlorinated solvents, I

recommend samples also be analyzed for chloride.

Response: As agreed during the RPM discussion on January 25, the work plan includes

sampling of aU monitor wells for chloride twice per year

C. Second paragraph: Dissolved oxygen concentrations should also be measured.

Edit text as appropriate.

Response: Agreed. See Item 3.C above.

Annotated Comments from SD DENR

Pride Hangar Area Treatment Work Plan 2 !8 February 2005

2,130 038
5. Page 10, Section 2.5 Ambient Monitoring, second complete paragraph, second

sentence: I recommend comparing sampling results to the most recent EPA Region 11I

Risk-Based Concentrations for ambient air, in addition to the Target Indoor Air

Concentrations. Edit text and Table 5 as appropriate.

Response: Agreed. This information has been added to the work plan.

6. Page 11:

A. Section 2.6 Sample Procedures, second paragraph: Table 5 presents a

summary of detected results in air samples. Provide a table with the referenced

information and edit text as appropriate.

Response: The text has been revised to reference Table 6.

B. Section 3.0 Pride Hangar Source Treatment Study Timing and Reporting,

second paragraph: Section 1.3 recommends installation of four injection wells.

Edit as appropriateto be consistent.

Response: This correction has been made in the work plan.

7. Tables 1, 2, 3 and 5: I request that the tables be edited to include all analytical results,

including non-detects. Present non-detects as "<##" rather than a blank space or dashed

lines. While this can create rather messy tables, it is important to compare detection

limits to standards or screening levels.

Response: "Less than" values have been entered to replace the "non-detect" values.

8. Table 4, SVE Operational Monitoring Results: Add a footnote to explain the

meeting of the asterisks in the table.

Response: A footnote has been added.

Annotated Comments from SD DENR

Pride Hangar Area Treatment Work Plan 3 18 February 2005

230 039