Assessment of Dredged Material for Management Decision Making

Transcription

1 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

2 Assessment Approach

3 Overview Program Objectives Defining the Project Other Considerations Regulatory Frameworks General Assessment Approaches Summary Q&A

4 Program Objectives Defining the project Project Purpose Project Design Volume of material Applicable management options How will material be handled?

5 Volume of Material Other Considerations 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.)

6 Material Characteristics Sands & gravel Silts and clays Organic content Contaminants How the material is handled Knock down Other Considerations Mechanical (open or closed bucket) Hydraulic (pipeline or hopper) Sensitive species or habitats

7 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)

8 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.)

9 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

10 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

11 Assessment Approach - Overview Upland 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

12 Assessment Approach - Overview Beneficial Use: Wetland Creation Compatible Toxicity Bioaccumulation Construction Fill Worker exposure Leachate quality Shoreline Restoration Compatible Toxicity Bioaccumulation

13 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)

14 Sampling & Analysis Design

15 Sampling and Analysis Overview The Sampling and Analysis Plan Project-Specific Considerations Analytical Design Sampling Design Sample Handling QA/QC References

16 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)

17 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)

18 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

19 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

20 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

21 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.)

22 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

23 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

24 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

25 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

26 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

27 Sampling Design Olympic Galvanizing, Inc.. Contaminant Zone Shore Dredging Project Area Channel Sand Current Direction

28 Sampling Design Contaminant Zone Shore Current Direction Sand Channel

29 Sampling Design Contaminant Zone X X X X X X Shore X X X o X Sand Current Direction Channel

30 Sampling Design Contaminant Zone X X X X X X Shore X X X o X Sand Current Direction Channel

31 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

32 Equipment- Sediment Cores Diver Core Box Core Piston Core Vibratory Gravity Core Vibracore

33 Equipment Sediment Grabs Van Veen Eckman Shipek

34 Equipment Water - Grabs Nisken Sampler Rossette Sampler

35 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

36 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

37 References USEPA/USACE, Inland Testing Manual USEPA/USACE, Ocean Testing Manual USACE, Upland Testing Manual USEPA, Methods for Collection, Storage, Manipulation of Sediments USEPA, QA/QC Guidance for Sampling and Analysis of Sediments, Water, and Tissues for Dredged Material Evaluations. EPA-823-B Higgins and Lee, 1987, Sediment Collection and Analysis Methods, Tech. Note EEDP USACE. ASTM, Standard Guide for Collection, Storage, Characterization and Manipulation of Sediment for Toxicity Testing, American Society of Testing and Materials.

38 Assessment & Data Interpretation

39 Overview Assessment for: In water placement/disposal Upland placement/management Other beneficial use options Summary Q&A

40 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

41 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

42 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: Sample DMMU-1 Elutriate Conc. % Survival % Normality Control LC50 EC 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 % - well below the lowest corrected LC50/EC50 value. Since << material meets the LPC for potential water column effects.

43 In Water Placement Disposal Longer-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).

44 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-1 72 (±7.6) Yes Yes Yes DMMU-2 75 (±7.6) Yes 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. DMMU-3 89 (±7.6) No No No

45 In Water Placement Disposal Longer-term indirect effects in higher trophic levels 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)

46 In Water Placement Disposal Longer-term indirect effects in higher trophic levels 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)

47 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

48 In Water Placement Disposal Exceedances generally preclude in water placement without additional engineering controls

49 Bioaccumulation Potential Analysis

50 Bioaccumulation Testing Clams 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 Polychaetes Freshwater oligochaetes

51 Why Assessing Effects on Fish is Complex? They move Species-specific differences: Connection to sediment Position in food web Site-specific differences: Size/configuration of the site Food web structure Non-equilibrium between sediment and water column

52 Interpreting Bioaccumulation Data 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.

53 Upland Placement/Management

54 Upland Placement/Management Effluent 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)

55 Upland Placement/Management Volatiles Comparison of volatile concentrations to air quality standards after dispersion modeling If it exceeds may require special management conditions (cover)

56 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)

57 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 Land Reclamation Creating Building Materials Shoreline Restoration

58 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

59 References USACE/USEPA Evaluation of Dredged Material Proposed for Discharge in Water of the US-Testing Manual. EPA-823-B USACE/USEPA Evaluation of Dredged Material Proposed for Ocean Disposal- Testing Manual. EPA-503/8-91/001. USACE Evaluation of Dredged Material Proposed for Disposal at Island, Nearshore, or Upland Confined Disposal Facilities- Testing Manual. ERDC/EL TR USEPA. Bioaccumulation Testing and Interpretation for the Purpose of Sediment Quality Assessment Status and Needs. EPA-823-R Specific Guidelines for Assessment of Dredged Material, London Convention 1972 & 1996 Protocol, July, 2012

60 Questions? Port of Oakland, CA 60