1 A1 Comparative Validation of Innovative Comparative Validation of Innovative Capping Technologies Capping Technologies Anacostia River, Washington DC Anacostia River, Washington DC Presented by Presented by Danny D. Reible Danny D. Reible Chevron Professor and Director Chevron Professor and Director Hazardous Substance Research Center/South & Southwest Hazardous Substance Research Center/South & Southwest Louisiana State University Louisiana State University 19 February 2003 19 February 2003
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A1 1 Comparative Validation of Innovative Capping Technologies Anacostia River, Washington DC Comparative Validation of Innovative Capping Technologies.
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11AA11
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
22AA22
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
• 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
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Steady State Cap PerformanceSteady State Cap Performance• Diffusion dominated systemDiffusion dominated system
– 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
• 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?
• 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)
• 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
2020AA2020
Demonstration Site – Anacostia Demonstration Site – Anacostia RiverRiver
• Anacostia River has documented Anacostia River has documented areas of sediment contaminationareas of sediment contamination
• 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
• 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
• 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
• 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
• 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
• 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 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
– 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
4545AA4545
Analytical MethodsAnalytical Methods
Analytical Parameter Aqueous Methodology Solid Methodology* Chemical
* 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).
4747AA4747
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