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A newsletter about soil, sediment, and ground-water characterization and remediation technologies

Triad Use at NavalBase San DiegoSaves an EstimatedSix Years and $3Million for SiteInvestigation page 1

Single FieldMobilizationCompletes SiteInvestigation andRemoval Actions page 3

Triad ExpeditesBrownfieldsRedevelopmentin Fairbanks page 4

NEWS TRENDSJanuary 2009Issue 40

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ContentsThis issue of Technology News and Trends highlights recent applications of Triad, an inte-grated site characterization and cleanup strategy that limits decision uncertainty and reducesproject duration and cost. In contrast to using one-time, exclusive steps typical of a linear strat-egy, Triad approaches conceptual site model development, planning, data review, characteriza-tion, and remedy implementation as real-time, evolving, iterative procedures. Applications de-scribed in this issue illustrate how direct sensing tools, field-based analytical methods, innova-tive sampling design, and data visualization and communication provide high-density, defen-sible datasets within a range of regulatory frameworks.

Online Resources

The Triad Resource Centeroffers technical tools anddocuments on systematicplanning, dynamic workstrategies, sample acquisitionand handling, measurementand data management,and regulatory acceptancefor Triad applications(http://www.triadcentral.org/).This web site also providesproject profiles highlightingcost and time savings atspecific sites.

Triad Use at Naval Base San Diego Saves an EstimatedSix Years and $3 Million for Site Investigation

The U.S. Naval Facilities EngineeringCommand Southwest (NAVFAC SW)used the Triad approach to collect anintegrated hydrogeologic and chemicaldataset for expediting and optimizingcharacterization of a volatile organiccompound (VOC) plume at Naval BaseSan Diego (NBSD), CA. The 295-acre“IR Site 22” was identified in 2003 whenVOC concentrations reaching 100 mg/Lwere reported in an upgradient well aspart of a remedial investigation at“NBSD IR Site 4.” As a result, NAVFACSW initiated investigative actions toidentify potential sources of VOCcontamination in ground water,determine whether the source(s) werecaused by Navy activities, and delineateVOCs in ground water.

IR Site 22 is located approximately threemiles southeast of downtown San Diego,on the east side of San Diego Bay. Thesite comprises reclaimed tidal landscovered by dredged material, andencompasses privately owned commercialand industrial properties in addition tothe NBSD.

IR Site 22 investigations leveraged all threeelements of Triad:

The stakeholder team initiated a system-atic planning process early in theproject; stakeholders included NAVFACSW, the Space and Naval Warfare Sys-tems Center (SPAWAR), the CaliforniaRegional Water Quality Control Board,and the California Department of ToxicSubstances Control. The team collabo-rated in developing data quality objec-tives (DQOs) and the conceptual sitemodel (CSM), which was used to de-sign a technical approach. Regulatorsvisited the site several times during fieldwork to participate in data interpreta-tion and decisions to “step out” sam-pling to additional locations.Field staff collected real-time in situmeasurements using a site character-ization and penetrometer system(SCAPS) truck equipped with onboardcone penetrometer testing and a mem-brane interface probe (CPT/MIP) anda direct sampling ion trap mass spec-trometer (DSITMS).Stakeholders collaborated in developinga dynamic work strategy to allow thefield team to step out dynamically tomeet project-specific DQOs. Web-based, near-real time communication of

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[continued from page 1]project data allowed stakeholders toview daily reports and remain engagedin the project as the CSM evolved.

The field work was conducted in threephases. Between each phase, asystematic planning meeting was heldto present current data and the updatedCSM and to optimize the followingwork phase.

Phase I involved a two-week lithologicand dense non-aqueous phase liquid(DNAPL) investigation using CPT withMIP and DITMS to build a detailedlithologic site model and identify VOCsource area(s). A total of 35 boringswere advanced to depths reaching 58feet below ground surface (bgs).Lithologic data from CPT were used toaugment existing information andexpand the CSM. Results indicated threepotential VOC source areas.

Phase II comprised a four-week, site-wide investigation of ground water.Using Phase I CPT and MIP data tooptimize locations and screenedintervals, a total of 24 direct-pushtemporary ground-water wells wereinstalled to depths of up to 40 feet bgs.Each temporary well was constructedusing nominal ¾-inch PVC casing witha 10-foot screened interval. Ground-water samples were collected for 24-hour-turnaround VOC analysis by afixed-base laboratory using U.S. EPAMethod 8260B. Eleven of the wells weresurveyed to determine hydraulic gradientacross the site.

Following evaluation of Phase I and IIresults, Phase III was initiated to addressdata gaps regarding the extent ofdissolved VOC plumes, include potential

preferential pathways in the refined CSM,and assess continuity between identifiedVOC source areas and VOCsindependently identified in IR Site 4ground water. This eight-week phaseinvolved collecting lithologic data from16 CPT borings, installing 22 additionaltemporary wells, and collecting ground-water samples for laboratory analysisof VOCs.

The collaborative data revealed two VOCplumes including tetrachloroethene(PCE) originating from offsite sourceson private properties (Figure 1). Resultsalso suggested contaminant migrationfavoring a subsurface paleochannelpreferential pathway. In total, the SCAPSproject team collected 2,775 vertical feetof lithologic data and 790 linear feet ofVOC concentration data representative

of the 295-acre site. The collaborativedataset included analytical results from49 ground-water samples.

Triad implementation provided anexpedited high-density dataset and arefined CSM in near-real time, resultingin cost avoidance estimated at $3 millionand schedule savings of approximatelysix years. The Navy continues to workwith regulatory stakeholders indeveloping a remedial strategy for IRSite 22.

Contributed by Jim Leather, Ph.D.SPAWAR System Center(jim.leather@navy.mil or 619 -553-6240) and Karen Collins, RichardBrady & Associates(kcollins@rbrady.net or 858-634-4516)

Figure 1. The updated NBSD CSMreflects ground water with PCEconcentrations exceeding 1,600 μg/L, asa result of contaminant plume migrationfrom an adjacent commercial facility.

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Single Field Mobilization Completes Site Investigation and Removal Actions

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The Kentucky Research Consortium forEnergy and the Environment (KRCEE)worked with the U.S. Department ofEnergy (DOE) last summer to introducenew approaches and technologies to thesite cleanup program operating at thePaducah Gaseous Diffusion Plant(PGDP) in western Kentucky. A Triaddemonstration was conducted atPGDP’s Area of Concern (AOC) 492that integrated several real-timecharacterization tools into dynamic workstrategies (DWSs) for expeditingcharacterization and remediation withinone field deployment. Field work focusedon methods to address uranium andpolychlorinated biphenyls (PCBs), twoof the most common soil and sedimentcontaminants at PGDP. Those methodsincluded laser-based gamma “walkover”surveys (GWS), x-ray fluorescence(XRF), in situ gamma spectroscopy(ISGS), PCB immunoassay kits, multi-increment sampling (MIS), and adaptivecompositing (AC).

The PGDP has operated for more than50 years and is now the only activeuranium enrichment facility in the UnitedStates. Past operations releasedcontaminants to ditches that emptied intoneighboring streams, contaminatingsediments. Maintenance activities withinthe streams and ditches resulted incontaminated sediments being placedon streams banks and adjacent uplandareas including AOC 492. Limitedhistorical information (three surfacesamples) identified uranium and PCBconcentrations of 1,150 and 44 ppm,respectively, in AOC 492 surface soil.

In the fall of 2007, a group of technicalrepresentatives from EPA Region 4, theCommonwealth of Kentucky, DOE,KRCEE, and Argonne NationalLaboratory (ANL) collaborated in asystematic planning session to devisethe initial CSM and form the project’sDWSs. The session yielded default risk-

based, wide-area averaged and hot spotproject criteria of 11 and 99 ppm,respectively, for uranium and 3.6 and 33ppm for PCBs. It also identified threeexposure units—based on a teenagerecreational user exposure scenario—within AOC 492. Based on anunderstanding of uranium processingand past experience, PCBs wereexpected to be collocated with uraniumcontamination. The field strategyincluded three activities deployed in onefield effort: characterizing the level andextent of soil contamination, excavatingsoil with concentrations exceedingproject criteria, and demonstrating post-excavation that project criteria wereattained for each of the exposure units.

The laser-based GWS for determining thepresence of elevated gamma radiation innear-surface soil was the first tool to bedeployed. Approximately 24,000 GWSdata points were collected over thecourse of three days, providing spatiallydense information (an average of fourmeasurements per square meter) about thelocation of uranium contamination in near-surface soil. Based on the GWS data, twentylocations were further sampled and analyzedby XRF and ISGS. The selected locationsspanned the range of GWS results; theXRF/ISGS data were used to develop arelationship between GWS results andsurface soil uranium concentrations. Oncethat relationship was established, uraniumhot spots could be identified based onGWS data (Figure 2), and the layout ofexposure units modified to reflect thespatial distribution of contamination.Approximately 13 m3 of soil weresubsequently removed from the uraniumhot spots and placed in an offsite disposalfacility. GWS and in situ XRF readingsverified that the excavation surface compliedwith the project hot spot criteria.

MIS and AC sampling techniques wereused jointly with the PCB immunoassaykits to verify that PCB hot spots did not

exist for the two exposure unitsconsidered most likely impacted bycontamination. MIS uses soil collectedfrom multiple locations spreadsystematically across a decision unit toform a sample that is more representativeof the average conditions across an areathan any one individual sample locationwould be. AC combines samples fromadjacent decision units into compositesbefore analysis; during the compositingprocess, the contributing samples aresplit, with one half of the splits archivedfor possible later analysis and the otherhalf used to make the composites. Fieldinvestigation levels are defined as afunction of the number of samplescontributing to the composite and theoriginal project criteria. If the analyticalresults of a composite exceed the fieldinvestigation level, each of the archivedsample splits contributing to thecomposite is analyzed. Use of MIS andAC minimized the number of sampleanalyses needed; only 23 werenecessary to verify compliance with hotspot and area-averaged cleanup criteriafor the entire study area. More than 300analyses would have been required ifeach of the soil increments had beenanalyzed individually.

Rigorous data quality control (e.g., useof calibration standards and controlcharts) was developed and implementedfor the project to ensure technicallydefensible datasets were obtained fromfield analytics. Data quality for the XRFuranium measurements was comparableto standard laboratory alphaspectroscopy data quality, with acorrelation coefficient of 0.99 anddetection limits at background levels.Each sample analyzed by immunoassayalso was analyzed at an offsitelaboratory for confirmation. In general,the PCB immunoassay kits comparedfavorably with laboratory total PCB

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Triad Expedites Brownfields Redevelopment in Fairbanks

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data, with a correlation coefficientgreater than 0.9.

The field work generated more than20,000 individual GWS data points,several hundred XRF measurements,and almost 400 surface soil increments.Characterization of AOC 492,contaminated soil removal, andverification that project criteria had beenachieved were completed in just 10 daysof field work. The use of MIS and ACsignificantly reduced the number of soilsamples requiring analysis, while theuse of field analytics reduced the costof each sample analysis. The availabilityof real-time data (e.g., XRF, ISGS,GWS, and PCB immunoassay kitresults) allowed a seamless integrationof characterization, remediation, andverification sampling. Demonstrationresults indicated that use of Triad and asuite of investigative tools effectivelycharacterized the soil, identified locations

requiring remediation, guided soilremoval, and verified that cleanup criteriawere achieved.

Contributed by Rich Bonczek, DOE-Portsmouth/Paducah Project Office

Figure 2. GWS results identified auranium hot spot in surface soil at PGDPAOC 492.

(Rich.Bonczek@lex.doe.gov or859-219-4051), Steve Hampson,KRCEE (502-564-8390 orskhampson@alltel.net), and RobertJohnson, ANL (rljohnson@anl.gov or630-252-7004)

The Fairbanks North Star Borough(FNSB) used Triad in 2006-2007 toassess environmental conditions at amunicipal property along the Chena Riverin Fairbanks, AK. FNSB accelerated thesite investigation as part of a brownfieldsassessment grant received from the U.S.EPA in 2005. Low-level contaminationhad been identified onsite in pastinvestigations, but its extent and impacton future redevelopment had not beenevaluated. FNSB anticipates integratingthe property into a 101-acre “ChenaRiverbend” multi-use project.

The 22-acre area of concern encompassesthe “Old City Landfill,” an autoimpoundment where petroleum and

metal contaminants may have beenreleased, and a municipal snow pilingarea potentially contributing polycyclicaromatic hydrocarbons (PAHs), totalpetroleum hydrocarbons, and metals frommelt water. From 1951 until 1965, theunregulated landfill was used formunicipal debris potentially containingmultiple contaminants of concern (COCs).The site subsequently was covered with5-20 feet of clean fill and developed forrecreational use.

The underlying soil consists of alluvial sandand gravel deposits with interbedded siltyoverbank deposits up to 500 feet thick.Ground water is shallow (8-15 feet bgs)and generally flows toward the adjacent

river. Limited Phase I investigations in2005 focused on ground-water and soilconditions in and below the landfill.Results indicated PCB and leadconcentrations in soil within the landfillexceeding regulatory criteria, as well asslightly elevated manganese and thalliumconcentrations in ground water.

The Alaska Department of EnvironmentalConservation (ADEC), U.S. EPA Officeof Superfund Remediation andTechnology Innovation, and U.S. ArmyCorps of Engineers-Seattle Districtassisted FNSB in Triad planning andimplementation, including establishingand refining the CSM. Key issues

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Figure 3. Sample depth contours fromthe Fairbanks “Old Landfill”geophysical survey revealed subsurfacedepths of landfill debris and fill.

concerning site development on thelandfill included gas emissions, potentialleachate, and the vertical and horizontalextent of debris. A high-level decisionflowchart was developed to correlaterelease/risk identification to siteredevelopment strategies.

Investigation activities included geophysicalsurveys, in situ soil-gas monitoring, testpit excavation and soil sampling, monitoringwell installation, and ground watersampling. A detailed flowchart wasestablished to allow CSM updates in thefield and provide criteria for decisions suchas sampling locations. For example,preliminary soil-gas sampling plans weredesigned on standard 300-foot grids inaccordance with EPA guidance forinvestigating landfills (EPA600-R-05-123).Field decisions allowed for adding samplinglocations within and outside the originalgrids and included triggers for additionalsampling supporting future modeling ofvapor pathways. (Initial ambient airmonitoring activity was cancelled due toground cover by snow and consequentreduction in fugitive gas emissions.)

To maximize application of Triad in a real-time environment, FNSB’s contractmechanism reflected flowchart options ona unit cost basis to allow for maximumflexibility during field work. Fieldinvestigations began in October 2007 withmobilization of drill rigs, excavators, anda field laboratory. Work started with a one-week geophysical survey using groundpenetrating radar to confirm the landfill’sareal extent (as determined in Phase Iinvestigation) and determine the landfilldepth. Survey results confirmed that thelandfill was confined to the western partof the site (Figure 3) with soil fill anddebris extending 25 feet bgs.

This information was used in real time toadjust sampling locations for soil-gas andground-water sampling. Soil probes wereadvanced above the landfill to depths of 7-8feet, and one soil-gas sample was extractedfrom each probe. Hand-held flameionization detectors (FIDs) andphotoionization detectors (PIDs) wereused to field screen each sample. Thoseshowing hits were analyzed for VOCs usinga portable gas chromatograph (GC) housedin a nearby trailer. Due to slow throughputof the field GC, some samples weresubmitted to a fixed laboratory for VOCanalysis; samples were selected fromlocations of low or non-detect PIDreadings across the landfill footprint.Over one week, 94 soil gas samples werecollected, 41 samples were analyzed withan onsite GC, and 6 samples weresubmitted to the offsite laboratory.

Results from the PID screening of soil gaspredicted higher and more extensive VOCconcentrations than the other methods.PID readings indicated concentrations of0-165 parts per million by volume (ppmv),while field GC and fixed laboratory resultsindicated only two detections, which werebelow 1 ppmv. This difference suggestedpresence of volatile compounds withionization potentials less than 10.6 EV,which were not included in other analyses.

The six fixed-laboratory results indicatedthat field screening results may not have

quantified soil-gas concentrations. Fixedlaboratory results indicated presence ofbenzene and PCE above ADEC draftscreening levels of 3.1 and 8.1 µg/m3,respectively. Other compounds such astrichloroethene and carbon tetrachloridealso exceeded screening levels in at leastone location. PID measurements werenot detected for three of the samples atthese locations due to detection limitshigher than the fixed laboratory’s.Laboratory results also did not agree withfield GC data showing non-detects (withthe exception of one sample) andgenerally indicated interference fromnon-target hydrocarbons. Although themethods did not agree with respect toconcentrations, all three methodsindicated VOC presence above screeninglevels throughout the landfill. Thisinformation was deemed sufficient forplanning purposes.

Traditional, non-Triad methods wereused to initially investigate the autoimpound and snow piling areas. Six testpits were excavated and soil sampleresults indicated that concentrations ofmetals and PAHs in the two areas didnot exceed regulatory criteria, andadditional planned sampling using Triadmethods was unnecessary.

The geophysical survey and soil-gassampling results were used to select five

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6EPA is publishing this newsletter as a means of disseminating useful information regarding innovative and alternative treatment techniques andtechnologies. The Agency does not endorse specific technology vendors.

Presorted StandardPostage and Fees PaidEPAPermit No. G-35

Solid Waste and EPA 542-N-09-001Emergency Response January 2009(5203P) Issue No. 40

United StatesEnvironmental Protection AgencyNational Service Center for Environmental PublicationsP.O. Box 42419Cincinnati, OH 45242

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Contact Usmonitoring well locations on the landfillperimeter for evaluation of flowdirection and potential release ofleachate into the river. The wells wereinstalled with 5-foot screens set atdepths to encompass historical highand low ground-water levels. Onlyarsenic was detected at concentrationsexceeding state regulatory criteria forground water in one (downgradient)well, where concentrations reached 55.2µg/L (above the 50 µg/L ADEC actionlevel). Remaining COCs were eitherbelow state criteria or not detected in anyof the monitoring wells.

Results indicating VOC and methanepresence prompted collection of soil andgrain-size samples for future airmodeling. Soil-gas FID and PID dataindicated landfill methane concentrationsof 0-8,600 ppmv, while field GC analysisfound concentrations reaching 20,700

ppmv. Findings suggest future onsiteactivities need to account for potentialmethane concentrations above the lowerexplosive limit (50,000 ppmv).

Project results indicated that FNSB could:

Develop the auto impound and snowpiling areas without restrictions, andEmploy soil-gas management strategiessuch as subslab venting to prevent va-por intrusion into onsite buildings.

The entire sampling program wasconducted in a single mobilization overtwo months at a cost of approximately$200,000, in contrast to a traditional siteinvestigation estimated at $300,000 overfive months.

Contributed by Tami Sheehan, FNSB,(tsheehan@co.fairbanks.ak.us or907-459-1240) and Kym Takasaki, U.S.Army Corps of Engineers-Seattle District(kymberly.c.takasaki@usace.army.milor 206-764-3322)

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