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Comparative Validation of Innovative Comparative Validation of Innovative Capping TechnologiesCapping Technologies

Anacostia River, Washington DCAnacostia River, Washington DC

Presented byPresented by

Danny D. ReibleDanny D. Reible

Chevron Professor and DirectorChevron Professor and DirectorHazardous Substance Research Center/South & Southwest Hazardous Substance Research Center/South & Southwest

Louisiana State UniversityLouisiana State University

19 February 200319 February 2003

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Hazardous Substance Research CenterHazardous Substance Research Center

South and Southwest

• Established under CERCLA (Recompeted 2001)

• Mission• Research and Technology Transfer

• Engineering management of contaminated sediments• Primarily focused on in situ processes and risk management• Unique regional (4&6) hazardous substance problems

• Outreach• Primarily regional in scope• Driven by community interests and problems

LSU

Rice Georgia TechTexas A&M

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Selecting Remedial OptionsSelecting Remedial Options

• NAS Committee On PCB NAS Committee On PCB Contaminated SedimentsContaminated Sediments– Recommended framework Recommended framework

of Presidential and of Presidential and Congressional Commission Congressional Commission on Risk Assessment and on Risk Assessment and ManagementManagement

• Key pointsKey points– Manage the risks not Manage the risks not

simply surrogates of risk simply surrogates of risk like concentration or masslike concentration or mass

– Engage stakeholders early Engage stakeholders early and oftenand often

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Sediment ManagementSediment Management

• Risk controlled by relatively small well defined areas Risk controlled by relatively small well defined areas (hot spots) in dynamic sediment environment with (hot spots) in dynamic sediment environment with defined on-shore disposal options?defined on-shore disposal options?– Encourages removal optionsEncourages removal options

• Risk defined by diffuse contamination in stable Risk defined by diffuse contamination in stable sediment environment?sediment environment?– Encourages in situ management optionsEncourages in situ management options

• What about other sites?What about other sites?– Requires site specific assessment and conceptual model Requires site specific assessment and conceptual model

developmentdevelopment– There are no default options; site specific assessment There are no default options; site specific assessment

necessary!necessary!

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In Situ Capping - AdvantagesIn Situ Capping - Advantages

• Armors sediment for containmentArmors sediment for containment– Can be designed to be stable in high flow conditionsCan be designed to be stable in high flow conditions– High confidence in describing dynamics of noncohesive, granular High confidence in describing dynamics of noncohesive, granular

mediamedia– Eliminates uncertainty of existing sediment dynamicsEliminates uncertainty of existing sediment dynamics

• Separates contaminants from benthic organismsSeparates contaminants from benthic organisms– Eliminates bioturbation (primary source of exposure and risk in Eliminates bioturbation (primary source of exposure and risk in

stable sediments)stable sediments)– Typical flux reduction at steady state by factor of 1000Typical flux reduction at steady state by factor of 1000

• Reduces diffusive/advective flux Reduces diffusive/advective flux – Increased transport path and sorption-related retardationIncreased transport path and sorption-related retardation– Time to achieve steady state may be thousands of yearsTime to achieve steady state may be thousands of years

• Provides opportunities for habitat developmentProvides opportunities for habitat development

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Cap EffectivenessCap Effectiveness

• Replaces particle transport processes with porewater Replaces particle transport processes with porewater processesprocesses– Elimination of erosion and bioturbation as transport Elimination of erosion and bioturbation as transport

processesprocesses– Diffusion (always present)Diffusion (always present)– Advection if seepage significant (highly variable)Advection if seepage significant (highly variable)

• Reduces steady state contaminant fluxReduces steady state contaminant flux

• Additional reduction in transient in flux Additional reduction in transient in flux – Reduces migration during transient consolidation of Reduces migration during transient consolidation of

sediment and cap materialssediment and cap materials– Reduces transient migration through capReduces transient migration through cap

– Partition coefficient, KPartition coefficient, Kswsw (Organics- K (Organics- Kswsw ~ f ~ fococKoc )Koc )

– RRff = = bb K Kswsw

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6 cm

2 cm

Terrebonne Bay, LAJanuary 31, 2001

A7

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Steady State Cap PerformanceSteady State Cap Performance• Diffusion dominated systemDiffusion dominated system

– Flux prior to capping Flux prior to capping • NNAA//bbWWss ~ 1 cm/yr (without erosion) ~ 1 cm/yr (without erosion)

– Flux after cappingFlux after capping• NNAA/ / bbWWs s ~ D~ Dcapcap/L/Leff eff RRff

• For pyrene, 1 ft cap - .001 cm/yr (RFor pyrene, 1 ft cap - .001 cm/yr (R ff~ O[10~ O[1033])])

• Advection dominated systemAdvection dominated system– Typically only small portions of sediment bedTypically only small portions of sediment bed– Flux after capping ultimately approaches prior fluxFlux after capping ultimately approaches prior flux– Sediment concentrations are dependent upon Sediment concentrations are dependent upon

sorptive capacity of capping materialsorptive capacity of capping material• Sand - low steady state concentrations near cap-water Sand - low steady state concentrations near cap-water

interfaceinterface

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hcap

hsed/Rf hsed

h0

Sediment Consolidation

Cap Layer

Bioturbation Layer

Overlying Water

hbio

hcap

Cap Consolidation

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Cap Design Factors - StabilityCap Design Factors - Stability

• Top layer stabilityTop layer stability– Design velocity or stresses (e.g. 100 year flood)Design velocity or stresses (e.g. 100 year flood)– dd5050(ft) = 1/4(ft) = 1/4cc (lb/ft (lb/ft22) (Highway Research Board)) (Highway Research Board)

• Non-uniform size distribution Non-uniform size distribution – dd8585/d/d15 15 > 4> 4

• Angular shapeAngular shape• Maximum particle size <2 dMaximum particle size <2 d5050

• Minimum particle size > 0.05 dMinimum particle size > 0.05 d5050

• Thickness > 1.5 dThickness > 1.5 d5050

• Adjacent layers:dAdjacent layers:d5050 ( layer 1) / d ( layer 1) / d5050 (layer 2) < 20 (layer 2) < 20– Especially important for armored caps or caps using coarse grained Especially important for armored caps or caps using coarse grained

material for habitat enhancement to avoid washout of finer materialmaterial for habitat enhancement to avoid washout of finer material

• Transition zone length: 5 times cap thicknessTransition zone length: 5 times cap thickness

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Current Issues in Cap DesignCurrent Issues in Cap Design

• Optimal placement over very soft sedimentsOptimal placement over very soft sediments• Placement of fine-grained, heterogeneous materialsPlacement of fine-grained, heterogeneous materials• Chemical containmentChemical containment

– NAPL seepsNAPL seeps– Gas generation and migrationGas generation and migration– Methyl mercury formation and migrationMethyl mercury formation and migration

• Design and effectiveness with groundwater seepageDesign and effectiveness with groundwater seepage– Assessment of seepage (and variation with time/space)Assessment of seepage (and variation with time/space)– Control of seepageControl of seepage

• StabilityStability– Selection of design flow, prediction of resulting stressesSelection of design flow, prediction of resulting stresses– Stability of innovative cap materialsStability of innovative cap materials

• Active Caps – Caps as a reactive barrierActive Caps – Caps as a reactive barrier

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Capping ConcernsCapping Concerns

• Contaminants are not removed or eliminatedContaminants are not removed or eliminated– Residual risk of cap loss Residual risk of cap loss

• But all remedial measures leave residual riskBut all remedial measures leave residual risk

• Intergenerational stewardship a “fact of life” for any Intergenerational stewardship a “fact of life” for any contaminated sediment site of any complexitycontaminated sediment site of any complexity

– Can caps be designed to ensure Can caps be designed to ensure • Migrating contaminants are eliminated?Migrating contaminants are eliminated?

• Residual pool of contaminants degrade over time?Residual pool of contaminants degrade over time?

• Continuing sources can recontaminate capContinuing sources can recontaminate cap– Continuing sources a problem for any remedial approachContinuing sources a problem for any remedial approach– Can caps be designed to reduce recontamination?Can caps be designed to reduce recontamination?

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Comparative Evaluation MetricsComparative Evaluation Metrics

• Primary metric – Risk Primary metric – Risk

• Secondary metrics Secondary metrics – Link to appropriate conceptual model of systemLink to appropriate conceptual model of system– Indicator species concentrations (e.g. fish)Indicator species concentrations (e.g. fish)– Contaminant mass (dynamic environment)Contaminant mass (dynamic environment)– Surficial average concentrations (stable Surficial average concentrations (stable

environment)environment)• When risk due to diffuse contamination (not “hot spots”)When risk due to diffuse contamination (not “hot spots”)

• SWAC – surface area weighted average concentrationSWAC – surface area weighted average concentration

– Integral measures (allows incorporation of time)Integral measures (allows incorporation of time)

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25% Breach – 28 ppm-yr

5% Breach – 19 ppm-yrNo Cap Breach – 16 ppm-yr

Fox River, Reible et al. (2003)

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Summary – Conventional Summary – Conventional CappingCapping

• Conventional sand caps easy to place and Conventional sand caps easy to place and effectiveeffective• Contain sedimentContain sediment• Retard contaminant migrationRetard contaminant migration• Physically separate organisms from contaminationPhysically separate organisms from contamination

• Methods are available for key design needsMethods are available for key design needs• Cap erosion and washout Cap erosion and washout • Cap and sediment consolidationCap and sediment consolidation• Chemical containmentChemical containment• Assessment of exposure and riskAssessment of exposure and risk

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Active CappingActive Capping

Can you Teach an Old Dog New Tricks?Can you Teach an Old Dog New Tricks?

Danny D. ReibleDanny D. Reible

Hazardous Substance Research Center/S&SWHazardous Substance Research Center/S&SW

Louisiana State UniversityLouisiana State University

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Potential of Active CapsPotential of Active Caps

• Sand caps easy to place and effectiveSand caps easy to place and effective• Contain sedimentContain sediment• Retard contaminant migrationRetard contaminant migration• Physically separate organisms from contaminationPhysically separate organisms from contamination

• Greater effectiveness possible with “active” Greater effectiveness possible with “active” capscaps– Encourage fate processes such as sequestration or Encourage fate processes such as sequestration or

degradation of contaminants beneath capdegradation of contaminants beneath cap– Discourage recontamination of capDiscourage recontamination of cap– Encourage degradation to eliminate negative Encourage degradation to eliminate negative

consequences of subsequent cap loss consequences of subsequent cap loss

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Active Capping Demonstration Active Capping Demonstration ProjectProject

• The comparative effectiveness of traditional The comparative effectiveness of traditional and innovative capping methods relative to and innovative capping methods relative to control areas needs to be demonstrated and control areas needs to be demonstrated and validated under realistic, well documented, in-validated under realistic, well documented, in-situ, conditions at contaminated sediment situ, conditions at contaminated sediment sites sites – Better technical understanding of controlling Better technical understanding of controlling

parametersparameters– Technical guidance for proper remedy selection and Technical guidance for proper remedy selection and

approachesapproaches– Broader scientific, regulatory and public acceptance Broader scientific, regulatory and public acceptance

of innovative approachesof innovative approaches

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Overall Project ScopeOverall Project Scope

A grid of capping cells will be established at a A grid of capping cells will be established at a wellwell

characterized contaminated sediment site:characterized contaminated sediment site:– Contaminant behavior before capping will be Contaminant behavior before capping will be

assessedassessed– Various capping types will be deployed within the Various capping types will be deployed within the

grid evaluating placement approaches and grid evaluating placement approaches and implementation effectivenessimplementation effectiveness

– Caps will be monitored for chemical isolation, fate Caps will be monitored for chemical isolation, fate processes and physical stabilityprocesses and physical stability

– Cap types and controls will be compared for Cap types and controls will be compared for effectiveness at achieving goalseffectiveness at achieving goals

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Demonstration Site – Anacostia Demonstration Site – Anacostia RiverRiver

• Anacostia River has documented Anacostia River has documented areas of sediment contaminationareas of sediment contamination

• Anacostia Watershed Toxics Anacostia Watershed Toxics Alliance (AWTA) offers unique Alliance (AWTA) offers unique opportunities opportunities

• Ultimate rehabilitation Ultimate rehabilitation approaches uncertainapproaches uncertain

• Much of current focus on Much of current focus on reducing contribution of sourcesreducing contribution of sources

• Areas adjacent to Navy Yard are Areas adjacent to Navy Yard are good candidate sites based on good candidate sites based on review of existing datareview of existing data

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Demonstration ParticipantsDemonstration Participants

• Lead Lead – Danny Reible, Hazardous Substance Research CenterDanny Reible, Hazardous Substance Research Center– Louisiana State UniversityLouisiana State University

• Prime Contractor Prime Contractor – Horne Engineering, Fairfax, VAHorne Engineering, Fairfax, VA– Yue Wei Zhu, Lead EngineerYue Wei Zhu, Lead Engineer

• SITE program evaluation of Aquablok SITE program evaluation of Aquablok – Vincente Gallardo, EPA CincinnatiVincente Gallardo, EPA Cincinnati

• Advisory GroupsAdvisory Groups– Anacostia Watershed Toxics AllianceAnacostia Watershed Toxics Alliance– Remediation Technology Development ForumRemediation Technology Development Forum

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Demonstration SiteDemonstration Site – Anacostia – Anacostia RiverRiver

• Two potential Two potential study areas study areas identified adjacent identified adjacent to Navy Yardto Navy Yard– First site has First site has

elevated PCBs and elevated PCBs and metals [1]metals [1]

– Second site is Second site is primarily PAHs [2]primarily PAHs [2]

– Some seepage, free Some seepage, free phase at depth at phase at depth at second sitesecond site

-77.04 -77.02 -77 -76.98 -76.96 -76.94

38.86

38.87

38.88

38.89

38.9

38.91

38.92

38.93

PotomacRiver

Washington

Ch

an

ne

l

ReganNationalAirport

WashingtonNavy Yard

S. Capitol St. Bridge11th St. Bridge

12th St. Bridge

Pennsylvania Ave. Bridge

Railroad Lift Bridge

E. Capitol St. Bridge

Benning Rd. BridgeKingmanLake

KenilworthAquatic

Gardens

NY Ave. Bridge

Anaco

stia

River

BladensburgMarina

HainsPoint

Washington DC

Tidal Basin

1 2

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Demonstration SitesDemonstration Sites

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Proposed Demonstration AreaProposed Demonstration Area

• The proposed demonstration areas are The proposed demonstration areas are approximately 200 ft by 500 ft approximately 200 ft by 500 ft (approximately 2 acres) adjacent the (approximately 2 acres) adjacent the shoreline upstream and downstream of shoreline upstream and downstream of the Navy Yardthe Navy Yard

• Each proposed pilot study cell is Each proposed pilot study cell is approximately 100 ft by 100 ft in size and approximately 100 ft by 100 ft in size and two or three study cells per area will be two or three study cells per area will be implemented. implemented.

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Demonstration SitesDemonstration Sites

• First Site – old CSO outfallFirst Site – old CSO outfall– South end of Navy YardSouth end of Navy Yard– PCBs: 6-12 ppmPCBs: 6-12 ppm– PAHs: 30 ppmPAHs: 30 ppm– MetalsMetals

• Cd: 3-6 ppmCd: 3-6 ppm Pb: 351-409 ppmPb: 351-409 ppm

• Cr: 120-155 ppmCr: 120-155 ppm Hg: 1.2-1.4 ppmHg: 1.2-1.4 ppm

• Cu: 127-207 ppmCu: 127-207 ppm Zn: 512-587 ppmZn: 512-587 ppm

• Second site – near old manufactured gas plantSecond site – near old manufactured gas plant– North end of Navy YardNorth end of Navy Yard– PAHs up to 210 ppmPAHs up to 210 ppm

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Potential Cap TechnologiesPotential Cap Technologies

• Six technologies undergoing bench scale testing and Six technologies undergoing bench scale testing and evaluation evaluation

• Bench scale testing objectivesBench scale testing objectives– Problems with physical placement?Problems with physical placement?– Problems with contaminant or nutrient release during Problems with contaminant or nutrient release during

placement?placement?– Problems with effectiveness with Anacostia contaminants?Problems with effectiveness with Anacostia contaminants?– What is appropriate cap design, homogeneous or layered What is appropriate cap design, homogeneous or layered

composite?composite?– What are key physical or chemical indicators of performance?What are key physical or chemical indicators of performance?

• Placement approaches also under evaluationPlacement approaches also under evaluation– Gravity tremie placement Gravity tremie placement – Layered placementLayered placement– Needlepunched mats (CETCO)Needlepunched mats (CETCO)

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Potential Cap TechnologiesPotential Cap Technologies

• Aquablok Aquablok – Control of seepage and advective contaminant transportControl of seepage and advective contaminant transport– Focus of EPA SITE AssessmentFocus of EPA SITE Assessment

• Zero-valent iron Zero-valent iron – Encourages dechlorination and metal reduction Encourages dechlorination and metal reduction – With or without sequestering amendments to retard migrationWith or without sequestering amendments to retard migration

• Phosphate mineral (Apatite)Phosphate mineral (Apatite)– Encourages sorption and reaction of metalsEncourages sorption and reaction of metals

• Coke Coke – Encourages sorption-related retardationEncourages sorption-related retardation

• BionSoil BionSoil – Encourage degradation of organic contaminants Encourage degradation of organic contaminants

• Natural organic sorbent Natural organic sorbent – Encourages sorption-related retardation Encourages sorption-related retardation

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AquaBlokAquaBlokTMTM

• Gravel/rock core covered by clay layerGravel/rock core covered by clay layer

• Expands in water decreasing permeabilityExpands in water decreasing permeability

• Applicable to seep locations (Site 2)Applicable to seep locations (Site 2)

• May be useful as funnel in “funnel and May be useful as funnel in “funnel and gate” reactive barrier designgate” reactive barrier design

• Semi-commercial technologySemi-commercial technology

• Treatability evaluation underway Hull & Treatability evaluation underway Hull & AssocAssoc

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Zero-Valent IronZero-Valent Iron

• Fe(0), Fe-S, Pd/Fe(0) under considerationFe(0), Fe-S, Pd/Fe(0) under consideration– Subject to cathodic reactions that yield hydrogenSubject to cathodic reactions that yield hydrogen

• Hydrogen can drive reductive biotic transformationsHydrogen can drive reductive biotic transformations• Reductive dechlorinationReductive dechlorination• Metal reductionMetal reduction

– Directly provide electrons for abiotic reductionDirectly provide electrons for abiotic reduction

• Chlorinated Organic Compounds (PCBs)Chlorinated Organic Compounds (PCBs)– Evaluation underway by Carnegie Mellon UniversityEvaluation underway by Carnegie Mellon University

• MetalsMetals– Evaluation underway by Rice UniversityEvaluation underway by Rice University

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Coke SorbentCoke Sorbent

• Coke BreezeCoke Breeze– 92% fixed carbon92% fixed carbon– 140 mm particles with 45-50% porosity140 mm particles with 45-50% porosity– Particle density of 1.9-2 g/cmParticle density of 1.9-2 g/cm33

– TCLP leachate – contaminants below detection TCLP leachate – contaminants below detection limitlimit

• Treatability testing underway at Carnegie Treatability testing underway at Carnegie Mellon UniversityMellon University

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Apatite BarrierApatite Barrier

Apatites – CaApatites – Ca55(PO(PO44))33OHOH• Subject to isomorphic substitutionSubject to isomorphic substitution

– PbPb55(PO(PO44))33OHOH– CdCd55(PO(PO44))33OHOH

• Reduces migration of metal speciesReduces migration of metal species• Employing XRF and XAS for metal species Employing XRF and XAS for metal species

dynamics and migrationdynamics and migration• Evaluation underway with LSU/University of Evaluation underway with LSU/University of

New HampshireNew Hampshire

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BionSoilBionSoilTMTM

• Manufactured soil from compostingManufactured soil from composting

• Hydrogen sourceHydrogen source– Enhancement of reductive dechlorinationEnhancement of reductive dechlorination– Enhancement of anaerobic degradation of PAHsEnhancement of anaerobic degradation of PAHs

• High organic contentHigh organic content– Encourages sorption and retardation of transportEncourages sorption and retardation of transport

• Evaluation underway at LSUEvaluation underway at LSU

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OrganoClay SorbentOrganoClay Sorbent

• Candidate - Biomin EC-100 organo-modified Candidate - Biomin EC-100 organo-modified clayclay– Low permeability Low permeability – High organic contentHigh organic content– Encourages retention of both non-aqueous and Encourages retention of both non-aqueous and

dissolved constituents dissolved constituents – Evaluated for control of active hydrocarbon Evaluated for control of active hydrocarbon

seeps in Thea Foss Waterway, WAseeps in Thea Foss Waterway, WA

• Treatability testing underway with Hart-Treatability testing underway with Hart-CrowserCrowser

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Other Potential Cap MaterialsOther Potential Cap Materials

• Ambersorb commercial sorbentAmbersorb commercial sorbent– Effective sorbent but high costEffective sorbent but high cost

• Activated carbon sorbentsActivated carbon sorbents– Effective sorbent intermediate in costEffective sorbent intermediate in cost– Primary focus on coke as cheaper (but less Primary focus on coke as cheaper (but less

effective carbon-based adsorbent)effective carbon-based adsorbent)

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Capping Demonstration Capping Demonstration ScheduleSchedule

• Technology Evaluations (Initial Phase) – Jun/Dec 2002Technology Evaluations (Initial Phase) – Jun/Dec 2002– Studies currently ongoing at LSU and collaborating Studies currently ongoing at LSU and collaborating

institutionsinstitutions

• Site Characterization – Jan-Apr 2003Site Characterization – Jan-Apr 2003– Phase 1 Geophysical Investigation (Jan 2003)Phase 1 Geophysical Investigation (Jan 2003)– Phase 2 Geotechnical and Chemical Assessment (Feb 2003)Phase 2 Geotechnical and Chemical Assessment (Feb 2003)– Phase 3 Biological Assessment (Apr 2003)Phase 3 Biological Assessment (Apr 2003)

• Cap Design – Jan/Jun 2003Cap Design – Jan/Jun 2003

• Cap Placement (Site 1) – Jul/Aug 2003Cap Placement (Site 1) – Jul/Aug 2003

• Cap Evaluation – Aug 2003/Sept 2004Cap Evaluation – Aug 2003/Sept 2004

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Site Characterization Site Characterization ObjectivesObjectives

• Establish the contamination baseline at Establish the contamination baseline at demonstration areasdemonstration areas– Define contaminant variabilityDefine contaminant variability– Identify and confirm appropriate areas for cap Identify and confirm appropriate areas for cap

demonstrationdemonstration

• Determine the geotechnical characteristics Determine the geotechnical characteristics of the sedimentof the sediment

• Provide necessary baseline data for future Provide necessary baseline data for future evaluation of effectiveness of capping evaluation of effectiveness of capping placement and capping technologiesplacement and capping technologies

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Site CharacterizationSite Characterization

• Preliminary physical assessment (Ocean Survey & R. Preliminary physical assessment (Ocean Survey & R. Diaz)Diaz)– Bathymetry measurement Bathymetry measurement – Side scan and sub-bottom profilingSide scan and sub-bottom profiling– Sediment profiling cameraSediment profiling camera

• Surficial sediment sample collectionSurficial sediment sample collection• Sediment coring sample collectionSediment coring sample collection• Sediment radionuclide characterization Sediment radionuclide characterization

– Historical depositionHistorical deposition– Average rate and extent of bioturbationAverage rate and extent of bioturbation

• Geotechnical data for the cap designGeotechnical data for the cap design• Historical Data Collection (groundwater seepage, flow Historical Data Collection (groundwater seepage, flow

velocity, and etc.)velocity, and etc.)• Biological Assessment (type and density)Biological Assessment (type and density)

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Site 1

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Site 2

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Site 1 – Typical Conditions• Sandy, oxidized surface• Gas voids

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Site 2 • Similar to Site 1in some areas• More organic and more mobile surface layer in other areas

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Site 2 – Disturbed area • Oxidized• Easily disturbed surface

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Chemical SamplingChemical Sampling

• Surficial sedimentsSurficial sediments– ~40 surficial sediment samples will be collected from ~40 surficial sediment samples will be collected from

each site four (4) inch and up to six (6) inch thick at each each site four (4) inch and up to six (6) inch thick at each grid point using a stainless steel Van Veen grab sampler grid point using a stainless steel Van Veen grab sampler or Petite Ponar grab sampler.or Petite Ponar grab sampler.

• Core sedimentsCore sediments– 8 cores will be collected from each site to a depth of 3 ft 8 cores will be collected from each site to a depth of 3 ft

• Samples collected from 0-6”, 6”-12” and 12”-36”Samples collected from 0-6”, 6”-12” and 12”-36”– Additional deeper cores will be used to assess underlying Additional deeper cores will be used to assess underlying

stratigraphy and provide geotechnical information for stratigraphy and provide geotechnical information for designdesign• One water sample from underlying sand unitOne water sample from underlying sand unit

– Additional shallow cores (gravity corer) employed to Additional shallow cores (gravity corer) employed to supplement baseline samplingsupplement baseline sampling

• Water samplingWater sampling– To define chemical baseline in water and potential for To define chemical baseline in water and potential for

recontamination of caps recontamination of caps

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Physical, Chemical, and Physical, Chemical, and Biological ParametersBiological Parameters Parameter Surficial

Sediment Core Sediment Sample

Water Column/ Pore-water

PCBs X X X PAHs X X X 8 RCRA Metal & Mercury X X X Total Organic Carbon X X Water Contents X X Total Kjeldahl Nitrogen X X pH X Total Suspended Solids X Salinity X DO X Conductivity X Benthic Macroinvertebrate X SAV Survey X

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Analytical MethodsAnalytical Methods

Analytical Parameter Aqueous Methodology Solid Methodology* Chemical

PAHs SW-846 5030B/8270C SW-846 8270C TCL Pesticides/PCBs SW-846 5030B/8180A SW-846 8180A PCBs SW-846 5030B/8082 SW-846 8082

8 RCRA Metals 7060A/7421/7740/7061/ 7131A/7191

7060A/7421/7740/7061/ 7131A/7191

Total Suspended Solids- (TSS) EPA 160.2 Not Applicable Total Kjeldahl Nitrogen EPA 351.3 EPA 351 modified Phosphorus EPA 365 EPA 365 modified Total Organic Carbon EPA 415, SW-846 9060 EPA 415 modified

Biological Benthic Macroinvertebrate EPA/600/4-90/030 SAV Survey General Acceptable Method

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Geotechnical ParametersGeotechnical Parameters

Parameter Number of Sample Method Grain Size Distribution 10 ASTM D421/422 Specific Gravity 4 ASTM D854 Atterberg Limits 10 ASTM D4318 Classification 10 ASTM D2487 In-Situ Vane Shear Test (Shear Test)

20 ASTM D2573

Unconsolidated, Undrained Strength

4 ASTM D 2850

Permeability* 4 ASTM D 2434 Consolidation** 4 ASTM D2435

USACE VIII Moisture Content 40 ASTM D2216 Bearing Capacity Calculated Slope Stability Calculated Note:

* One value of permeability must be calculated from the self-weight consolidation test.

** Use the Modified standard consolidation test and self-weight consolidation test as described in USACE 1987 (Department of Army Laboratory Soils Manual EM 1110-2-1906 -USACE 1970).

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Monitoring Cap EffectivenessMonitoring Cap Effectiveness

• Employ cores and dialysis samplers to define Employ cores and dialysis samplers to define placement and cap effectivenessplacement and cap effectiveness– Bottom of core – undisturbed sedimentBottom of core – undisturbed sediment– Middle of core – cap/sediment interfaceMiddle of core – cap/sediment interface

• Examine interlayer mixingExamine interlayer mixing• Examine contaminant migration/fate processesExamine contaminant migration/fate processes

– Top of core – cap/water interfaceTop of core – cap/water interface• Examine recontaminationExamine recontamination• Examine recolonizationExamine recolonization

• Supplement with physical monitoring Supplement with physical monitoring – Water column (flow, suspended sediment and chemical)Water column (flow, suspended sediment and chemical)– Non-invasive (sonar, bathymetry)Non-invasive (sonar, bathymetry)– Invasive (sediment profiling camera)Invasive (sediment profiling camera)

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SummarySummary

• Capping technologies undergoing bench-Capping technologies undergoing bench-scale evaluation and testingscale evaluation and testing

• Site characterization efforts currently Site characterization efforts currently underwayunderway

• Site 1 placement planned for summer 03Site 1 placement planned for summer 03– AquablokAquablok– Zero valent iron/coke breezeZero valent iron/coke breeze– ApatiteApatite

• Additional information www.hsrc-ssw.orgAdditional information www.hsrc-ssw.org