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“Setting the course”
www.pianc.org
Presenting
Assessment of Dredged Material for Management Decision Making
Burton Suedel, Ph.D.
and
David Moore, Ph.D.
COPEDEC
October 2016
Rio de Janeiro, Brazil
“Setting the course”
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Assessment Approach
“Setting the course”
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Overview
• Program Objectives– Defining the Project
– Other Considerations
– Regulatory Frameworks
• General Assessment Approaches
• Summary
• Q&A
“Setting the course”
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Program Objectives
Defining the project• Project Purpose
• Project Design
• Volume of material
• Applicable management options
• How will material be handled?
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Other Considerations• Volume of Material
– Smaller volumes <5,000 cubic meters
– Larger volumes >100,000 cubic meters
• Site Characteristics
– Site configuration (outfalls, etc.)
– Current land use
– Site history (previous dredging/clean-up history, legacy contamination, etc.)
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Other Considerations• Material Characteristics
– Sands & gravel
– Silts and clays
– Organic content
– Contaminants
• How the material is handled– Knock down
– Mechanical (open or closed bucket)
– Hydraulic (pipeline or hopper)
• Sensitive species or habitats
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Management Alternatives
The assessment approach will be determined by the range of management alternatives under consideration…
• In Water Placement/Disposal
• Upland Placement/Disposal
• Beneficial Use (in water and/or upland)
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Regulatory Frameworks
• International Treaty (The London Convention for Disposal of Wastes at Sea)
• National Regulatory Frameworks (US – CWA & MPRSA; EU- Water Directive; Japan – Env. Reg. on Ocean Dumping of Dredged Materials ; Mexico – Waste Disposal in Mexican Marine Zones, etc.)
• Local Regulatory Requirements (US –State Water Quality Requirements; State Residential Soil Criteria, etc.)
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Assessment Approach - Overview
General Elements:• Risk based approach utilizing multiple lines of
evidence
– Comparison to applicable numerical criteria and/or reference site/condition
– Physical (grain size, odor, color, etc.) and chemical characterization (bulk and elutriate chemistry)
– May include biological testing (toxicity and bioaccumulation)
• Suitability based on
– Risk-based assessment
– comparison to a criterion or standard
– comparison to a reference condition
– Or a combination of the above
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Assessment Approach - Overview
In water management options:• Relevant exposure pathways of interest are
– Direct toxicity to benthic organisms
– Direct toxicity to water column organisms (via elutriates)
– Uptake and transference of contaminants through the food web
• If there are potentially impacted species/habitats of special concern (e.g., coral, eelgrass, etc.) additional evaluation may be necessary
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Assessment Approach - OverviewUpland management options:
• Relevant exposure pathways include
• Direct toxicity to soil organisms and plants
• Uptake and transference of contaminants through the food web
• Potential impacts to groundwater
• If there is a return flow to a surface water body - may require consideration of water column impacts (elutriates)
• If there are potentially impacted species/habitats of special concern additional evaluation may be necessary
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Assessment Approach - OverviewBeneficial Use:•Wetland Creation
• Compatible
• Toxicity
• Bioaccumulation
•Construction Fill
• Worker exposure
• Leachate quality
•Shoreline Restoration
• Compatible
• Toxicity
• Bioaccumulation
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Assessment Approach - Overview
• Assessment approach based on the applicable regulatory frameworks which generally specify the process, procedures, & comparison points
• There may be features unique to a particular project or site that require special consideration (historic sediments with naturally occurring elevated metals)
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Sampling & Analysis Design
“Setting the course”
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Sampling and Analysis Overview
• The Sampling and Analysis Plan
• Project-Specific Considerations
• Analytical Design
• Sampling Design
• Sample Handling
• QA/QC
• References
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The Sampling and Analysis Plan
• Critical to success of project
• Stipulates how samples will be collected and analyzed
• Dependent on accurate and recent site information (bathymetry, etc.)
• Dependent on accurate and complete project information (dredging footprint, project depth, potential obstructions)
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The Sampling and Analysis Plan
• Serves as an agreement between regulators, permit applicant and contractor performing the work (e.g., compositing strategies, sample locations, etc.)
– Should include discussion of how results are to be interpreted and what will be included in final report
– Should attempt to identify potential problems encountered in the field and suggest contingencies (refusal/obstructions at designated sampling locations)
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The Sampling and Analysis Plan
Content:
• Background (location and description of the project, site history, previous studies)
• Objectives: purpose of the sampling and analysis to be performed
• Sampling & Analysis Design
– Overview of sampling design and rationale (including description of nature and type of samples to be collected)
– Overview of analysis to be performed and rationale
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The Sampling and Analysis Plan
Content:• Material and Methods
– Sample Collection & Handling
– Physical, Chemical, and Biological Analysis
– Documentation
– Quality Assurance and Quality Control
– Health and safety planning
• Reporting
• Schedule
• References
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Objectives• Representative – samples must be
collected such that they reflect material to be assessed (dredging site and placement site)
• Adequate – Sufficient material should be collected for the required analysis (including contingencies) and handled in a manner that ensures integrity to the point of analysis
• Reliable – appropriate collection, handling and analytical procedures using approved methods
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Project Specific Considerations
• Project Objectives
• Review of Dredging Plan (area, depth, volume, method, etc.)
• Local/Regional requirements
• Review of historical data
• Site characteristics
• Health & Safety concerns (UXO, utilities, etc.)
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Sampling Design
• Division of project area into Dredged Material Management Units (DMMUs)
• Number & location of samples within DMMUs
• Sample depth
• Stratification
• Contingencies (refusal, stratification, obvious signs of contamination, etc.)
• Compositing
• Sample handling
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Sampling Design- Subdivision of Dredging Area
• Dredging area can be divided into segments based on:– Historical data
– Sediment characteristics
– Geographical configuration
– Anticipated method of dredging
– Known contaminated areas
– Number of DMMUs should be sufficient to adequately represent the area to be dredged and generally reflective of how the material is likely to be dredged and managed
“Setting the course”
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Sampling Design - Number of Samples
• The number of sample locations within a DMMU are generally based on:– The size of the area represented by the DMMU
– Potential for contamination within a DMMU (to facilitate hotspot isolation)
– Time/funding constraints
• The numbers of samples per location within a DMMU should be based on:– Volume for the required analysis plus contingencies
– Time / funding constraints
“Setting the course”
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Sampling Design - Sample Location
• Areas above proposed design depth (shoals) and within the footprint
• Areas downstream from point sources
• Areas free of known impediments/hazards (rip rap, debris, utilities, UXO)
• Areas where fine grained material may be deposited (side channels and bends)
• Distribute sample locations throughout project/segment area
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Sampling Design-Compositing
• DMMUs are typically represented via a composite of the samples collected within the DMMU to reflect how the material will be managed
• Compositing represents an average of the sites sampled within the DMMU
• Compositing results in decreased description of variability within project area (hence its important to maintain archives of individual cores)
• Compositing is not intended as a means to dilute a highly contaminated area
“Setting the course”
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Sampling Design
Shore
Contaminant
Zone
Sand
Dredging
Project
Area
Channel
Olympic
Galvanizing,
Inc..
Current Direction
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Sampling Design
Contaminant
Zone
Sand
Channel
ShoreCurrent Direction
“Setting the course”
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Sampling Design
Contaminant
Zone
Sand
Channel
Shore
XX
X
X
X
X
Current Direction
X
X
X
X
o
“Setting the course”
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Sampling Design
Contaminant
Zone
Sand
Channel
Shore
XX
X
X
X
X
Current Direction
X
X
X
X
o
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Equipment
Sediment Cores• Diver cores
• Box cores
• Gravity Cores
• Push Cores
• Piston Cores
• Vibracores (electric or hydraulic)
• Barge mounted hollow stem auger
• Vibratory hammer cores
Sediment Grabs• Van Veen
• Ponar
• Bucket dredge
Water• Van Dorn/Kimmler grab sampler
• Bucket
• Pumps
“Setting the course”
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Equipment- Sediment Cores
Piston Core VibracoreVibratory Gravity Core
Diver Core Box Core
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Equipment – Sediment Grabs
Van Veen Eckman Shipek
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Equipment Water - Grabs
Nisken Sampler Rossette Sampler
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Sample Handling
• Handle sample according to published Standard Operating Procedures
– Container type
– Preservative
– Sample storage
• Handle sample to minimize changes in composition– Chemical
– Biological
– Avoid contamination
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Quality Assurance Quality Control
• Ensure sample integrity from point of collection to point of analysis (Chain of Custody)
• QA assures the quality of the data
• QC assures that procedures are followed to obtain quality data
“Setting the course”
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References– USEPA/USACE, 1998. Inland Testing Manual
– USEPA/USACE, 1991. Ocean Testing Manual
– USACE, 2003. Upland Testing Manual
– USEPA, 2001. Methods for Collection, Storage, Manipulation of Sediments
– USEPA, 1995. QA/QC Guidance for Sampling and Analysis of Sediments, Water, and Tissues for Dredged Material Evaluations. EPA-823-B-95-001.
– Higgins and Lee, 1987, Sediment Collection and Analysis Methods, Tech. Note EEDP-06-1. USACE.
– ASTM, 2008. Standard Guide for Collection, Storage, Characterization and Manipulation of Sediment for Toxicity Testing, American Society of Testing and Materials.
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Assessment & Data Interpretation
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Overview
Assessment for:• In water placement/disposal
• Upland placement/management
• Other beneficial use options
• Summary
• Q&A
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In water placement disposal
• Short-term water quality impacts– Potential impacts to water column
organisms
• Longer-term sediment quality impacts– Direct toxicity to benthic organisms
– Indirect effects to higher trophic levels via contaminants uptake and transference through the food web
“Setting the course”
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In Water Placement Disposal
Short Term Water Column Impacts associated with dredging and disposal
• Chemical analysis of sediment elutriates, application of a mixing zone model (STFATE) followed by comparison to WQC.
• Elutriate Toxicity tests with selected water column organisms. Evaluate results after allowance for mixing (e.g., STFATE model). If the modelled elutriate concentration < 0.01 of the calculated LC50/EC50 value material meets the LPC.
• Exceedances of WQC or toxicity may preclude in water placement but generally indicate additional engineering controls are required
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Suspended Particulate Phase Analysis Example
• Based on results of the three species SPP tests the lowest LC50/EC50 value obtained was for the bivalve development tests with M. galloprovenciallis in the DMMU-1 Composite sample:
SampleElutriate Conc.
% Survival% Normality
LC50 EC50
DMMU-1
Control 99.7 95.5
70.2 54.2
1 99.5 96.2
10 94.9 95.0
50 79.6 52.5
100 2.6 0.0
• Applying a safety factor of 0.01 to the EC50 value of 54.2 we obtain a value of 0.542%.
• Entering the sediment grain size data for the DMMU-1 composite and other requisite parameters for the STFATE model (i.e., scow size, disposal site water depth, current velocity, etc.) we calculate an LPC of 0.0012% - well below the lowest corrected LC50/EC50 value.
• Since 0.0012 << 0.542- material meets the LPC for potential water column effects.
“Setting the course”
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In Water Placement DisposalLonger-term direct effects on benthic biota• Analysis of bulk sediment
• Exceed regulatory standard (e.g., The Netherlands)
• Evaluate in toxicity tests to establish whether unacceptable toxicity to benthic organisms exposed to the material relative to a reference.
• Exceedances generally preclude open water placement w/out additional engineering controls (e.g., placement in a CAD site).
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Solid Phase Analysis Example
• Results of SP tests show some reduced survival in 2 of the 3 DMMU’s evaluated in tests with the amphipod A. abdita:
Sample% Survival
(S.D.)Statistically Diff. relative to Ref. ?
More than 20% < than
Ref. ?
Exceed the LPC?
Control 98 (±7.6) NA NA NA
Reference 93 (±7.6) NA NA NA
DMMU-172 (±7.6)
Yes Yes Yes
DMMU-275 (±7.6)
Yes No No
DMMU-389 (±7.6)
No No No
• Based on these results DMMU-2 & 3 meet the LPC and are suitable for ocean disposal.
• DMMU-1 exceeds the LPC and therefore is not suitable for ocean disposal.
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In Water Placement Disposal
• Analysis of bulk sediment • Exceed regulatory standard (e.g.,
Japan).
• Apply model to measured sediment.
concentration to estimate uptake in
aquatic biota and compare estimated
tissue concentrations to regulatory
standards for fish tissue and or
available effects data (e.g., ERED)
Longer-term indirect effects in
higher trophic levels
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In Water Placement Disposal
• Apply model to measured tissue residues to evaluate ecological and human health risk (Trophic Trace, BRAMS).
• Comparison of modelled concentrations to TRVs (eco) or Human Health Risk based standards (Cancer, Non Cancer)
Longer-term indirect effects in
higher trophic levels
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In Water Placement Disposal
• Conduct bioaccumulation test to determine whether unacceptable bioaccumulation of contaminants in benthic organisms exposed to the material relative to a reference.
–Comparison to Action Limits
• Evaluation of data considering 8 factors
• Number of species elevated relative to reference
• Number of contaminants elevated relative to reference
• Magnitude of elevation relative to reference
• Toxicological significance (literature-based)
• Phylogenetic diversity of the species.
• Propensity to biomagnify (Kow)
• Magnitude of toxicity and number of species exhibiting greater mortality
• Comparison to regional reference
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In Water Placement Disposal
• Exceedances generally preclude in water placement without additional engineering controls
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Bioaccumulation Potential Analysis
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• Conduct whole-sediment bioaccumulation tests
(typically 28-d long) using sufficient biomass for
tissue chemistry – large organisms preferable.
• Compare dredged material to reference
• Accumulation of chemicals of interest in
organisms as endpoint
Bioaccumulation Testing
Clams
Polychaetes Freshwater oligochaetes
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• They move
• Species-specific differences:
– Connection to sediment
– Position in food web
Why Assessing Effects on Fish is Complex?
• Site-specific differences:
– Size/configuration of the site
– Food web structure
– Non-equilibrium between sediment and water column
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• Compare to action limits (e.g., Food and Drug Administration; FDA)
• Compare bioaccumulation in dredged material vs. reference material for statistical differences and magnitude of difference (additional factors also apply)
• Compare tissue concentrations to levels known to cause effects– If concerns with bioaccumulation in fish and wildlife exist, the evaluation
becomes more complex and expert help is typically required. The Bioaccumulation Risk Assessment Modeling System (BRAMS) is an executable program available at the ERDC website for obtaining estimates of exposure and risk.
Interpreting Bioaccumulation Data
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Upland Placement/Management
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Upland Placement/ManagementEffluent and Runoff• Compare concentrations measured in
simulated effluents with WQ standards (may include allowance for mixing)
• If it exceeds may require special management conditions (treatment prior to discharge)
Leachate• Compare concentrations from leachate tests
with applicable groundwater and surface water standards
• If it exceeds may require special management conditions (impermeable liner, collection, and treatment)
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Upland Placement/Management
Volatiles• Comparison of volatile
concentrations to air quality standards after dispersion modeling
• If it exceeds may require special management conditions (cover)
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Upland Placement/Management
Direct Contact• Application of models to measured sediment
concentrations to estimate uptake in plants and animals followed by comparison to EcoSSLs
• Conduct bioaccumulation test to determine whether unacceptable bioaccumulation of contaminants in plants and soil invertebrates exposed to the material relative to a reference followed by comparison to EcoSSLs
• Apply model to measured tissue residues to evaluate ecological and human health risk
• Exceedances indicate need for special management conditions to eliminate unacceptable risk (i.e., cover)
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Beneficial Use
• Many of the same pathways are evaluated for beneficial use
• Analysis and evaluation may need to be tailored to better reflect likely exposure scenarios and receptors of concern
Shoreline Restoration
Land Reclamation
Creating Building Materials
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Summary• Establishing suitability of
dredged material for a particular management option is based on multiple lines of evidence
• Assessment and interpretation is risk-based
• Application of tools such as Trophic Trace can be used to help inform decision but should not preclude “common sense”
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References– USACE/USEPA 1998. Evaluation of Dredged Material Proposed for Discharge
in Water of the US-Testing Manual. EPA-823-B-98-004.
– USACE/USEPA 1991. Evaluation of Dredged Material Proposed for Ocean Disposal- Testing Manual. EPA-503/8-91/001.
– USACE. 2003 Evaluation of Dredged Material Proposed for Disposal at Island, Nearshore, or Upland Confined Disposal Facilities- Testing Manual. ERDC/EL TR-03-1.
– USEPA. Bioaccumulation Testing and Interpretation for the Purpose of Sediment Quality Assessment – Status and Needs. EPA-823-R-00-001.
– Specific Guidelines for Assessment of Dredged Material, London Convention 1972 & 1996 Protocol, July, 2012
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Questions?
60
Port of Oakland, CA
