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TRANSCRIPT
Presented to
Presented by
Best Practices Group
Clay Patmont Anchor Environmental, LLC
Emerging Trends in Emerging Trends in Contaminated Sediment Contaminated Sediment
CleanupCleanup
August 28, 2008
Presentation OutlinePresentation Outline
•• Overview of emerging trendsOverview of emerging trends––Regulatory and industry initiativesRegulatory and industry initiatives––Key technical developmentsKey technical developments
•• Dredging technology limitationsDredging technology limitations•• Monitored natural recovery and capping Monitored natural recovery and capping
case studiescase studies•• Low cost in situ treatmentLow cost in situ treatment
––Adaptive ManagementAdaptive Management
Regulatory and Industry InitiativesRegulatory and Industry Initiatives
•• EPAEPA’’s 11 Sediment Management Principless 11 Sediment Management Principles•• National Academy of Sciences (NAS)National Academy of Sciences (NAS)
–– A Risk Management Strategy for PCBA Risk Management Strategy for PCB--Contaminated SedimentsContaminated Sediments–– Sediment Dredging at Superfund Megasites: Assessing EffectivenesSediment Dredging at Superfund Megasites: Assessing Effectivenesss
•• Sediment Management Work Group (SMWG)Sediment Management Work Group (SMWG)•• EPA Contaminated Sediment GuidanceEPA Contaminated Sediment Guidance•• EPA Contaminated Sediments Technical EPA Contaminated Sediments Technical
Advisory Group (CSTAG)Advisory Group (CSTAG)•• State ProgramsState Programs
EPAEPA’’ss 11 Sediment Management 11 Sediment Management PrinciplesPrinciples
1.1. Control Sources EarlyControl Sources Early
2.2. Community InvolvementCommunity Involvement
3.3. Coordinate With Other Coordinate With Other
StakeholdersStakeholders
4.4. Sediment Stability ModelSediment Stability Model
5.5. RiskRisk--Based FrameworkBased Framework
6.6. Carefully Evaluate DataCarefully Evaluate Data
7.7. SiteSite--Specific Risk Specific Risk
ManagementManagement
8.8. Risk Driven Goals Risk Driven Goals
9.9. Maximize Institutional Maximize Institutional
Controls Controls
10.10. RiskRisk--Driven Remedies Driven Remedies
11.11. Monitor RemedyMonitor Remedy
National Academy of Sciences National Academy of Sciences (NAS)(NAS)
•• A Risk Management Strategy for PCBA Risk Management Strategy for PCB-- Contaminated SedimentsContaminated Sediments–– Overall risk reduction focusOverall risk reduction focus–– No presumptive remedyNo presumptive remedy
•• Sediment Dredging at Superfund Megasites: Sediment Dredging at Superfund Megasites: Assessing the EffectivenessAssessing the Effectiveness–– Site conditions determine dredging effectivenessSite conditions determine dredging effectiveness–– Risk reduction focus (not mass removal)Risk reduction focus (not mass removal)
Sediment Management Work GroupSediment Management Work Group
1.1. 1010--year historyyear history2.2. Industry lessons learnedIndustry lessons learned3.3. Adaptive management frameworkAdaptive management framework4.4. Collaboration with EPA and CorpsCollaboration with EPA and Corps
•• Joint technical conferencesJoint technical conferences•• Sediment Remediation GuidanceSediment Remediation Guidance
EPA Contaminated Sediment GuidanceEPA Contaminated Sediment Guidance
1.1. Focus on risk reduction, not simply removalFocus on risk reduction, not simply removal2.2. Realistic, siteRealistic, site--specific evaluation of optionsspecific evaluation of options3.3. Comparative net risk reduction evaluationComparative net risk reduction evaluation4.4. Combined remedies at complex sitesCombined remedies at complex sites5.5. Adaptive management based on new dataAdaptive management based on new data6.6. Compare costs and benefitsCompare costs and benefits
•• Disproportionate cost analysisDisproportionate cost analysis
EPA Contaminated Sediment EPA Contaminated Sediment Technical Advisory Group (CSTAG)Technical Advisory Group (CSTAG)
•• Site monitoring and advisory roleSite monitoring and advisory role•• Large, complex, or controversial sitesLarge, complex, or controversial sites•• Limited number of sites currently in programLimited number of sites currently in program•• EPA regional and headquarters interactionsEPA regional and headquarters interactions
State Regulatory InitiativesState Regulatory Initiatives
•• Existing State programsExisting State programs–– Washington, Florida and CaliforniaWashington, Florida and California–– Disproportionate cost analysesDisproportionate cost analyses
•• Emerging State programsEmerging State programs•• Interstate Technology & Regulatory CouncilInterstate Technology & Regulatory Council
Key Technical DevelopmentsKey Technical Developments
•• Case studies of biological recoveryCase studies of biological recovery–– Monitored natural recoveryMonitored natural recovery–– CappingCapping–– DredgingDredging
•• Dredging technology limitationsDredging technology limitations•• Low cost in situ treatmentLow cost in situ treatment
Biological Recovery Case StudiesBiological Recovery Case Studies
•• Monitored natural recoveryMonitored natural recovery–– Bellingham Bay, WA (20+ years)Bellingham Bay, WA (20+ years)–– Grasse River, NY (15+ years)Grasse River, NY (15+ years)
•• CappingCapping–– St. Paul Waterway, WA (15+ years)St. Paul Waterway, WA (15+ years)–– Eagle Harbor, WA (15+ years)Eagle Harbor, WA (15+ years)
•• DredgingDredging–– Commencement Bay, WA (25+ years)Commencement Bay, WA (25+ years)–– Duwamish Waterway, WA (30+ years)Duwamish Waterway, WA (30+ years)
Bellingham Bay Site Conditions and Bellingham Bay Site Conditions and Natural Recovery TimelineNatural Recovery Timeline
Chemicals of Potential Concern
Source Control Implementation
Monitoring Record
Mercury & Wood Waste
Mercury - ’70 Wood - ’72, ’78, ’99 Log Pond Cap – ’00/’01
30+ Years RI/FS - ’96, ’98 Pre-RD – ’02
Mercury Release and Source Mercury Release and Source Control: Bellingham BayControl: Bellingham Bay
0
1
2
3
4
5
6
7
8
1960 1970 1980 1990 2000
Mer
cury
Loa
ding
(kg/
day)
Nooksack River – “Background”
Chlor/Alkali Source
Data Source: Patmont et al. (2004)
Temporal Change in Core Profiles:Temporal Change in Core Profiles: Inner Bellingham BayInner Bellingham Bay
-70
-60
-50
-40
-30
-20
-10
00 2 4 6 8 10 12
Sedi
men
t Dep
th (c
m)
19701975
1996
Sediment Mercury (mg/kg)
Data Source: Patmont et al. (2004)
Natural Recovery Biological Natural Recovery Biological Endpoint: Sediment ToxicityEndpoint: Sediment Toxicity
Toxicity tests:Toxicity tests:–– Amphipod: Amphipod:
acute toxicityacute toxicity–– Larval: Larval:
acute toxicity acute toxicity & abnormality& abnormality
–– Polychaete: Polychaete: chronic toxicity chronic toxicity & growth& growth
2002
Data Source: Patmont et al. (2004)
Safe Seafood Mercury LevelsSafe Seafood Mercury Levels
FDA Guidelines1.0 ppm tissue
EPA Guidelines 0.30 ppm tissue
Bellingham Bay Crab Testing
Ecology Studies (1991)0.06 to 0.15 ppm
PSDDA Program Studies (1991)0.03 to 0.09 ppm
Log Pond Monitoring (2002, 2005)0.01 to 0.03 ppm
Sea
food
Tis
sue
Mer
cury
Con
cent
ratio
ns
Site-SpecificScreening Level 0.18 ppm tissue
Monitored Natural Recovery:Monitored Natural Recovery: Grasse River, Massena, NYGrasse River, Massena, NY
Natural Recovery Biological Natural Recovery Biological Endpoint: Fish Tissue PCB LevelsEndpoint: Fish Tissue PCB Levels
0
500
1000
1500
2000
1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008
ppm lipid
Brown Bullhead PCB
ROPS Dredging
(26,000 cy)
Data Source: Alcoa (2007)
Source Control
Commencement BayCommencement Bay SuperfundSuperfund Site, WASite, WA
St. Paul Waterway Capping and St. Paul Waterway Capping and Habitat Restoration, Tacoma, WAHabitat Restoration, Tacoma, WA
St. Paul Waterway Sediment St. Paul Waterway Sediment Remediation & Restoration TimelineRemediation & Restoration Timeline
Site Discovery and Hazard Assessment
RI/FS and Cleanup Plan
Remedial Design and Permitting
Post-Construction Monitoring & NRD Settlement
Wood Waste (phenolics), PAHs, Cu
Sediment Toxicity Targeted Containment Remedy Identified
Source Controls Implemented Integrated Cap and Habitat Restoration Design
Physical Integrity and Chemical Stability Biological Productivity/Enhancement
St. Paul Cap After 1988 ConstructionSt. Paul Cap After 1988 Construction
•• Primary measure of project successPrimary measure of project success•• Rapid recolonization by benthic, Rapid recolonization by benthic,
epibenthic, and macrophyte epibenthic, and macrophyte communitiescommunities
•• Indistinguishable from reference areas Indistinguishable from reference areas within a few yearswithin a few years
St. Paul Cap Biological MonitoringSt. Paul Cap Biological Monitoring
St. Paul Cap Performance MetricsSt. Paul Cap Performance Metrics
PHYSICAL•Cap Integrity Confirmed Following Initial Placement•Final Bathymetric Monitoring in Year 15 (2004)•Storm/earthquake contingency monitoring, as needed
CHEMICAL•Chemical Stability and Source Control Confirmed•Final Verification Sampling in Year 10 (1998)
BIOLOGICAL•Primary Criteria •Biological Recovery Within 2 Years of Construction•Biological Enhancement/NRD Restoration •Final Biological Sampling in Year 10 (1998)
Cap Performance Example:Cap Performance Example: Eagle Harbor, WAEagle Harbor, WA
Trawl
Cap Performance Biological Cap Performance Biological Endpoint: Flatfish Liver LesionsEndpoint: Flatfish Liver Lesions
English Sole Liver Lesion TrendsBainbridge Island, WA
0%
10%
20%
30%
40%
50%
60%
1982 1984 1986 1988 1990 1992 1994 1996 1998 2000
Year
Age
-Adj
uste
d Li
ver L
esio
n Fr
eque
ncy
Nisqually/Carr/Colvos Reference
Eagle Harbor
East Harbor Capping
Data Sources: Myers et al. (2001) & WDFW (2002)
Sediment Concentrations and Sediment Concentrations and Flatfish Liver LesionsFlatfish Liver Lesions
0%
5%
10%
15%
20%
25%
30%
35%
40%
0.1 1 10 100Area-Average Sediment PAH Conc (mg/kg dry wt)
Live
r Les
ion
Prev
alen
ce
Eagle Harbor Pre-Cleanup
(1993)
Eagle Harbor Post-Cleanup
(1997-99)Puget Sound Background
Data Source: Anchor (2002)
Commencement BayCommencement Bay SuperfundSuperfund Site, WASite, WA
Blair and Sitcum Blair and Sitcum WaterwaysWaterways
•• PCB, PAH, and PCB, PAH, and metalsmetals
•• Navigation needs Navigation needs importantimportant
•• 1993 1993 -- 1994 1994 dredging and dredging and disposaldisposal
Trawl
Sitcum Waterway Dredging: 93 Sitcum Waterway Dredging: 93 -- 9494
Hylebos, Middle & Thea Foss Hylebos, Middle & Thea Foss Waterway Dredging and Disposal: Waterway Dredging and Disposal: 2002 2002 -- 20052005
Commencement Bay Dredging Commencement Bay Dredging Performance: Fish Tissue PCBsPerformance: Fish Tissue PCBs
English Sole Muscle PCB TrendsCommencement Bay, WA
0
50
100
150
200
250
300
350
400
450
500
1982 1987 1992 1997 2002 2007
Year
Tota
l PC
Bs
(ug/
kg w
et w
t; +/
- 2 s
td. e
rr.)
Nisqually/Carr Reference
Commencement Bay
ROD
Miscellaneous Brownfield
Projects
Hylebos, Middle & Thea Foss Waterway Dredging
(~1,100,000 cy)
Blair & Sitcum Waterway Dredging
(~400,000 cy)
Data Sources: TetraTech (1985), West and O’Neill (2007) & WDFW (2007)
Duwamish Waterway and Harbor Island Duwamish Waterway and Harbor Island SuperfundSuperfund Sites, WASites, WA
Trawl
East Waterway Dredging East Waterway Dredging –– 2003 to 20052003 to 2005
Duwamish Waterway Performance Duwamish Waterway Performance Biological Endpoint: Fish Tissue PCBsBiological Endpoint: Fish Tissue PCBs
English Sole Muscle PCB TrendsDuwamish Waterway, WA
0
1,000
2,000
3,000
4,000
5,000
6,000
7,000
1972 1977 1982 1987 1992 1997 2002 2007
Year
Tota
l PC
Bs
(ug/
kg w
et w
t; +/
- 2 s
td. e
rr.)
Nisqually/Carr Reference
Duwamish Waterway
Duwamish/Diagonal, East Waterway, Lockheed &
Todd Shipyard Dredging (~600,000 cy)
Data Sources: Miller et al. (1977), Malins et al. (1982), Metro (1983), EPA (1988), West & O’Neill (2007), WDFW (2007) & Stern et al. (2007)
Ecological Recovery Lessons LearnedEcological Recovery Lessons Learned
•• Documented ecological recovery from Documented ecological recovery from monitored natural recovery and monitored natural recovery and completed capping projectscompleted capping projects
•• Little evidence to date of net ecological Little evidence to date of net ecological recovery from completed dredging recovery from completed dredging projectsprojects
•• Dredging technology limitationsDredging technology limitations
Dredging Technology LimitationsDredging Technology Limitations
•• Environmental dredging Environmental dredging and processesand processes
•• ““4Rs4Rs”” 2008 Report2008 Report•• Management implicationsManagement implications
Conceptual Illustration ofConceptual Illustration of Environmental Dredging and Environmental Dredging and
ProcessesProcesses
Removal
Resuspension
Release
(Water)
Release
(Air)
Residual (Sediment)
Residual
1.1. Undisturbed Residuals: Undisturbed Residuals: Contaminated sediment Contaminated sediment that remains after dredging below the design that remains after dredging below the design interface (i.e., the interface (i.e., the ““neat lineneat line””))
Estimating ResidualsEstimating Residuals
Neat Line
Residual Sediment
What are Residuals?
2.2. Generated Residuals: Generated Residuals: Contaminated sediment Contaminated sediment dislodged but not removed by dredgingdislodged but not removed by dredging
Primary Sources of ResidualsPrimary Sources of Residuals
Contaminated Sediment
Clay
SandBedrock
Nepheloid LayerNepholoid layer flows
Some material left behind
Slight turbidity
Slope failure into bite
Estimating ResidualsEstimating Residuals•• Residual mass balance Residual mass balance
using database of using database of completed projectscompleted projects–– Range of 2 to 9% by mass Range of 2 to 9% by mass
(Avg. 5%)(Avg. 5%)–– Residual conc. equal to Residual conc. equal to
average of sediment dredgedaverage of sediment dredged Residuals ≈
1.5 cm
Nepheloid ≈
3.5 cm
Turbid Water
Z-layer
Case Study Summary of Case Study Summary of Generated ResidualsGenerated Residuals
0%
1%
2%
3%
4%
5%
6%
7%
8%
9%
10%
0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4
Average In-Situ Dry Density of Last Production Cut (gms/cm3)
Gen
erat
ed R
esid
ual (
% o
f las
t pro
duct
ion
cut)
Little Debris or Rock/Hardpan
Debris and/or Rock/Hardpan
Residual Management OptionsResidual Management Options
•• Monitored Natural RecoveryMonitored Natural Recovery•• Residuals Cap or Sand CoverResiduals Cap or Sand Cover•• Engineered Isolation CapEngineered Isolation Cap•• Additional Dredging (Production or Additional Dredging (Production or
Cleanup)Cleanup)
Decision Tree
Decision Tree ConsiderationsDecision Tree Considerations
•• Nature of residuals (undisturbed vs. Nature of residuals (undisturbed vs. generated)generated)
•• Characteristics of residuals (thickness, Characteristics of residuals (thickness, density, concentration)density, concentration)
•• Site conditionsSite conditions•• Environmental benefit and effectiveness of Environmental benefit and effectiveness of
additional dredgingadditional dredging
Low Cost In Situ TreatmentLow Cost In Situ Treatment
•• Activated Carbon AdditionActivated Carbon Addition–– Laboratory studies (Stanford, Univ. Maryland)Laboratory studies (Stanford, Univ. Maryland)–– FieldField--scale pilot studiesscale pilot studies
•• San Francisco Bay (CA)San Francisco Bay (CA)•• Grasse River (NY)Grasse River (NY)
–– Results to date very promisingResults to date very promising
•• Satisfies CERCLA preference for permanenceSatisfies CERCLA preference for permanence•• Engineering considerationsEngineering considerations•• Cost comparisonsCost comparisons
Activated Carbon Pilot Study AreaActivated Carbon Pilot Study Area
Activated Carbon Placement Techniques Roto-Tiller
Activated Carbon Placement Techniques Tine Sled
Field and Lab PCB Bioaccumulation Studies
Laboratory exposure test with L. variegatus
In-river deployment of field exposure cages with L. variegatus for baseline study
L. variegatus
Activated Carbon Pilot Study Activated Carbon Pilot Study –– Results to DateResults to Date
1. Activated carbon successfully delivered to sediments using a range of different methods
2. No construction water quality impacts
3. All of the activated carbon added in fall 2006 remained in sediments in fall 2007; declining spatial variability
4. Activated carbon bound most of the PCBs in surface sediments and rendered them unavailable to biota
5. Minor change in erosion potential of treated sediments
6. No measureable changes to benthic community
7. Additional work underway:• Follow-on testing in August 2008
• Potential applications to Grasse River sediment cleanup remedy
Sediment Delivery System Concept1. Agglomerate containing AC delivered from water surface2. Sinks to sediment surface and resists resuspension
3. Breaks down slowly3. Breaks down slowly
Water C
olumn
BiologicallyActive Zone
Deep
Sediment
Time
4. Mixed into sediment by bioturbation
Activated Carbon and Sand ApplicationActivated Carbon and Sand Application
55
Potential Activated Carbon ApplicationsPotential Activated Carbon Applications
1. Potential substitute for caps
2. Direct application to surface sediments• Typical unit cost < $50,000/acre
3. Incorporate activated carbon into cap
4. In situ treatment remedies supported by EPA guidance
Adaptive ManagementAdaptive Management
•• Grasse River Case StudyGrasse River Case Study–– Early source control and longEarly source control and long--term monitoringterm monitoring–– Pilot studies of dredging, capping, and in situ Pilot studies of dredging, capping, and in situ
treatment technologiestreatment technologies
•• Fox River Case StudyFox River Case Study–– New data drove ROD AmendmentNew data drove ROD Amendment–– Combined dredging and capping remedyCombined dredging and capping remedy–– Value engineering and cost reductionValue engineering and cost reduction