Real Property Institute of Canada

2014 RPIC Federal Contaminated Sites National Workshop

April 2014

Esquimalt Graving Dock Waterlot Remediation Project (Phase 1B)

Confirmatory Sampling, Analysis and Evaluation Plan (CSAEP) Implementation

and Dredging Residuals Management

Stream H: Contaminated Sites Management for Aquatic Environments and Sediment

Presenter: David McKeown (SLR Consulting) Collaborators: Jeff Nyman (SLR), Andrew Mylly (PWGSC), Rae Ann Sharp (PWGSC), Tom

Wang (Anchor QEA), Dan Berlin (Anchor QEA), Matt Woltman (Anchor QEA)

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Project Background •  The EGD is a federally owned, operated and maintained

facility. •  Ship repair and maintenance facility for military and

civilian vessels since 1927. •  Industrial activities at the EGD have resulted in

contamination of the surrounding sediments. •  PWGSC managed the remediation project through

FCSAP funding. •  The Waterlot Remediation Program aimed to clean up

the site to meet federal and provincial environmental standards.

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Project Background (Cont’d) •  Primary CoCs in sediment included Metals, PAH, and PCB. •  Other contaminants included TBT, Dioxins/Furans, and

Pesticides. •  Contaminant levels identified as IL+ for disposal

considerations. •  Contaminated sediments were removed through remedial

dredging and off-site disposal. •  Confirmatory sediment sampling program designed and

implemented to verify that remedial targets were met. •  Decision criteria developed to determine potential re-

dredging and/or Remedial Management Cover (RMC) placement requirements.

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Project Location

Esquimalt Graving Dock

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Project  Boundary  

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Photo  courtesy  of  Heath  Moffa5  

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Objectives •  CSAEP developed to outline standardized procedures for

collection of post-dredge sediment samples. •  Establish methods to characterize and assess post-dredge

sediment quality. •  Provide an evaluation process to verify whether remedial

targets were met through dredging activities. •  Provide project staff with a guidance tool to conduct

sampling, assess resulting information, and determine whether additional actions were required.

•  Also used as a baseline planning tool for cost estimates to implement the sediment quality assessment program.

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Study Design •  Waterlot divided into 11 dredge zones

based on pre-dredge contaminant profiles. –  Zone 10 further broken into sub-zones

•  Dredge zones sampled after completion of dredging activities using a 25 x 25 m grid spacing.

•  Locations identified in field using sub-metre accuracy GPS

•  Vibracore samples collected at each location with concurrent surface grab samples (petite ponar).

•  Diver cores collected where unable to obtain vibracore samples.

•  Test pit samples collected during low tide in intertidal area of Munroe Head. Photo  courtesy  of  Heath  Moffa5  

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•  Sediment quality assessment conducted for each dredge zone and sub-zone individually.

•  Confirmatory sediment cores and concurrent grab samples collected at each location for analytical testing. –  Cores were sampled at 0.5 m intervals to identify missed inventory

contamination. –  Surface grab samples were used to identify dredge residual

contamination.

•  Slope samples also collected prior to slope armouring to aid in future risk assessment updates. –  Not included in re-dredge decisions due to geotechnical considerations.

•  Over 200 post-dredge locations sampled.

Study Design 11 / 37

Remedial Objectives •  Numeric Remedial Action Objectives:

–  Based on most stringent and previously accepted applicable marine environmental quality guidelines, including:

•  CCME Marine Sediment PEL •  BC CSR Sediment Criteria for Typical Contaminated Sites •  Puget Sound Dredge Disposal Analysis & Site-specific TBT

assessment (Golder) •  NRAOs derived for:

–  Metals –  PAH –  PCB –  Dioxins & Furans –  TBT –  Select Pesticides

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Sample Collection, Handling and Processing

•  Core samples collected by vibracoring vessel.

•  Cores advanced in to sea floor 2 to 3 m or until refusal.

•  Core tubes cut open to facilitate sample processing.

•  Core compaction corrections applied based on penetration depth vs. recovery core length.

–  Minimum recovery targets established for acceptance of cores.

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Sample Collection, Handling and Processing

•  Samples collected at 0.5 m intervals along cores.

–  Upper 1.0 m samples submitted for analysis.

–  Remaining samples archived.

•  Samples homogenized within each interval to ensure representative samples.

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Sample Collection, Handling and Processing

Concurrent grab samples collected using petite ponar sampler.

Diver assisted grabs/cores collected where vibracoring was not possible (e.g., dry dock sill area, hard substrate areas).

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Sample Collection, Handling and Processing

Munroe Head intertidal area (Zone 9) sampled by test-

pitting during low tides.

All grab, core, test pit samples homogenized to be representative.

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Laboratory Coordination and Submissions

•  Prepared Laboratory Statement of Requirements to define: –  Required detection limits to meet NRAO levels. –  Turn-around-times for specific parameters. –  Detailed schedule for samples and analysis requirements on a

daily, weekly and monthly basis. –  Communication requirements. –  Data management and QA/QC requirements.

•  Electronic COC submissions. •  Sample pick-up/delivery coordinated through laboratory.

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Data Management •  Dedicated web-based Environmental

Management Tool (EMT) developed to provide accessible and up to date data repository.

•  Remote access for project personnel. •  Laboratory results loaded

automatically to the EMT. •  Data manager included on project to

provide QA/QC review, data tabulation and management, and statistical analysis.

•  Sediment quality compared to NRAOs

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Data Management (EMT) 19 / 37

Confirmatory Sample Assessment •  Post-dredge compliance decision framework generated

for assessment of sediment quality. •  Post-dredge sediment quality was assessed using two

methods: –  Overall dredge zone compliance with NRAOs based on

statistical approach (surface samples only). –  Single point compliance assessment.

•  Surficial samples compared to 4X NRAO threshold to assess dredge residual contamination. –  Considered eventual mixing of upper sediment layers (up to 10

cm) with placed RMC layer (30 cm)

•  Core samples compared to 1X NRAO to assess missed inventory contamination.

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Re-Dredge Decision Process •  Initial re-dredge decision based on 3-day TAT parameters

(metals, PAH, PCB). –  These parameters were drivers in most zones and other contaminants (i.e.,

pesticides, TBT, dioxins/furans) were generally shown to co-locate. –  Pesticides, TBT, dioxins/furans analyzed on a 7-day TAT. –  Where other parameters were drivers within a zone, results were re-

assessed once they became available. –  Modifications to the re-dredge decision were then provided to the contractor.

•  10-day turn around requirement in specifications to provide re-dredge decision to contractor.

•  Consultant design team and PWGSC personnel reviewed information from each zone in accordance with decision framework. –  Re-dredge decisions formally relayed to contractor through PWGSC.

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Re-Dredge Decision Process •  Contingency re-dredge depths

determined based on whether residual or missed inventory contamination was present within dredge zone and/or each sampling grid.

•  Additional surface grab samples collected following re-dredging.

•  Sediment quality from second sampling round was re-assessed in accordance with the post-dredge compliance decision framework. –  Residuals assessment only.

Photo  courtesy  of  Heath  Moffa5  

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Post-Dredge Compliance Decision Framework ZONE DREDGING

COMPLETED

CONFIRMATORY SAMPLING

(Vibracore and Surface Sampling)

SURFACE SAMPLING

(0 – 0.1 m)

Analytical Data Receipt, Tabulation and Review

Lab analysis (3-7 working days)

CORE SAMPLING (0 – 2.0 m with min 75% recovery)

Composite samples to lab (0-0.5 m and 0.5-1.0 m)

Archive Samples below 1.0 m

(in 0.5 m intervals)

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Post-Dredge Compliance Decision Framework COMPLIANCE UNIT ASSESSMENT

(based on surface samples only)

Method 1 – Single Sample Assessment Method 2 – Statistical Approach

Are the surface sample

concentrations less than NRAO?

Are there any surface sample concentrations >4X NRAO?

Is the 90th Percentile or 95% UCLM surface sample

concentrations below NRAO?

Is the 90th Percentile or 95% UCLM surface sample concentrations

below NRAO? If No, RMC thickness to be evaluated based on in-situ

concentrations

RESIDUAL RE-DREDGE (0-0.3 m)

PLACE RMC RESIDUAL RE-

DREDGE (0-0.3 m)

YES  NO  

YES  NO:  <4X  NRAO   NO:  >4X  NRAO  

YES  

If  <NRAO  

If  <4X  NRAO  

2nd Round Surface Sampling 2nd Round Surface Sampling

YES  

NO:  <4X  NRAO  

NO FURTHER ACTION

REQUIRED

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Post-Dredge Compliance Decision Framework MISSED INVENTORY ASSESSMENT

(based on sediment cores)

Is the core sample concentration below NRAO?

Is the confirmatory surface sample concentration below the NRAO?

MISSED INVENTORY RE-DREDGE (0.5-0.8 m)

NO FURTHER ACTION

REQUIRED

PROCEED TO COMPLIANCE UNIT

ASSESSMENT METHOD

2nd Round Surface Sampling

NO  

YES  

YES  

NO  

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Surface Sample Results

<NRAO  

1-­‐4  X  NRAO  

>4X  NRAO  

Results Analysis - Example 26 / 37

Core Sample Results

<NRAO  

1-­‐4  X  NRAO  

>4X  NRAO  

Results Analysis - Example 27 / 37

Results Analysis - Example Re-Dredge Areas

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Z03-12

Contingency •  In select cases, additional re-dredge passes were

conducted if concentrations in final surface grabs remained elevated above 4X NRAO.

•  In other cases where additional re-dredging was not possible due to presence of hard substrates (e.g., till), diver surveys were conducted to document residual sediment layer thickness in order to adjust final predictions of COC concentrations after mixing.

•  Assessment was conducted to determine whether increased RMC placement in these select areas would adequately reduce anticipated final concentrations.

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Final Surface Concentrations Before RMC

<NRAO  

1-­‐4  X  NRAO  

>4X  NRAO  

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RMC Placement Assessment •  In areas where surface sediment contamination was

identified > 1X NRAO following required and/or contingency dredging, concentrations evaluated to determine if placement of RMC material (minimum 0.3 m thickness) would provide for sufficient mixing and attenuation to meet the NRAO target.

•  In select cases where surface concentrations remained above 4X NRAO and additional re-dredging was not feasible or not considered to be effective, thicker RMC layers were applied.

•  Areas identified for RMC placement reviewed by design team and requirements were relayed to the contractor.

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Post-Remediation Baseline Assessment

•  Vibracore sampling at several locations within each dredge zone where RMC was placed. –  Combined with RMC thickness assessment

•  RMC thickness was verified within each core and compared to survey information.

•  Baseline sediment quality within the upper 0.3 m was collected to provide baseline information for future studies to validate assumptions of post-remediation mixing.

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10 cm

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Surface Concentrations After RMC Placement

<NRAO  

1-­‐4  X  NRAO  

>4X  NRAO  

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<NRAO  

Future Monitoring

•  Long-term sediment quality assessments to be conducted to validate surface mixing assumptions and to determine trends over time.

•  Sediment coring and analytical testing of upper 0.3 m in previously sampled locations.

•  Comparison to baseline sediment quality established through RMC Assessment Sampling.

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Lessons Learned •  Logistical considerations and staffing requirements/re-scheduling were

difficult and required appropriate budgeting and time allocation for proper planning.

•  Areas where hard substrates were encountered proved to difficult to obtain adequate samples. –  Diver cores required in some locations. –  Very hard substrate areas only allowed for diver grabs. –  Program modified in select areas to conduct diver video surveys to

document residual sediment layer thickness to re-adjust post-mixing assumptions where further re-dredging was not feasible or effective.

•  RMC coring was difficult due to lower core retention. –  Adjustments were needed in coring technique to provide adequate recovery.

•  Overall challenges were realized with 10-day turn-around for response to contractor.

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Special Thanks to:

•  Andrew Mylly (PWGSC) •  Rae Ann Sharp (PWGSC) •  Kristen Ritchot (PWGSC) •  David Osguthorpe (PWGSC) •  Chris Major (PWGSC) •  Jeff Nyman (SLR) •  Marci Martin (SLR) •  Richard Plourde (SLR) •  Hailey O’Neill (SLR) •  Ingrid Sorensen (SLR) •  Cheryl Nyman (SLR) •  Heather Grant (SLR) •  Coastline Technologies Inc.

•  South Coast Diving Ltd. •  Ben McKinnon (SLR) •  David Grafton (SLR) •  Ricki Sahota (SLR) •  Drew Rice (SLR) •  Vanya Jongkind (SLR) •  David Pugh (SLR) •  Aaron Haegele (SLR) •  Chris Koziey (SLR) •  Matt Woltman (Anchor QEA) •  Dan Berlin (Anchor QEA) •  Tom Wang (Anchor QEA) •  Bud Whitaker (Anchor QEA) •  Joe Persley (Anchor QEA) •  Geoff Cooper (KCB) •  Tervita •  FRPD

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