Amendment 0004 Attachment 1-MSU Portland Sediment Report.pdf

SEDIMENT CHARACTERIZATION REPORT

for

MAINTENANCE DREDGING

at

UNITED STATES COAST GUARD MARINE SAFETY UNIT

PORTLAND, OREGON

Prepared for:

United States Coast Guard Civil Engineering Unit Oakland

1301 Clay Street, Suite 700N Oakland, CA 94612

May 2024

THIS PAGE WAS INTENTIONALLY LEFT BLANK

SEDIMENT CHARACTERIZATION REPORT

for

MAINTENANCE DREDGING

at

UNITED STATES COAST GUARD MARINE SAFETY UNIT

PORTLAND, OREGON

Contract Number 70Z05019DBBECPI02 Task Order 70Z08822FESDV0053

USACE Permit No. NWP-2013-172-1

Prepared for:

United States Coast Guard

Civil Engineering Unit Oakland 1301 Clay Street, Suite 700N

Oakland, CA 94612

Prepared by:

BB&E, Inc.

235 E. Main Street, Unit 107 Northville, MI 48167

May 2024

Sediment Characterization Report May 2024 MSU Portland Dredging i

EXECUTIVE SUMMARY

The Level 2A (physical and chemical) sediment analyses documented within the report were completed to support sediment dredging and disposal activities for the United States Coast Guard (USCG) Marine Safety Unit (MSU) Portland facility located in Portland, Oregon (Figure 1). An estimated dredge volume of 560 cubic yards (CY) is expected from the 2024 dredge footprint, with a potential total dredge volume of approximately 3,000 CY over two additional dredge events within a 10-year period. The sampling data were collected to allow a local review team to make suitability determinations regarding the placement of dredged sediments and exposure of the post-dredge surface.

The dredged sediment is expected to be disposed of offsite at the Hillsboro Landfill located in Hillsboro, Oregon.

The proposed dredge area was assigned one dredged material management unit (DMMU) for characterization purposes and is identified as DMMU1. The single DMMU was assigned a Management Area Rank (MAR) of moderate.

Sediment cores were collected from four coring stations within the maintenance dredge prism. Sufficient sediment material was collected to complete Level 2A analyses. Sediment samples collected from the four coring stations included one sample from each station within the dredge prism (to -12 feet (ft) Columbia River Datum [CRD]) and one sample from the Z-layer (-12 to -14 ft CRD).

After completion of the Level 2A analyses, results were compared to the Freshwater Benthic Toxicity SL1 Screening Levels (SLs) provided in the Sediment Evaluation Framework for the Pacific Northwest (SEF;

Northwest Regional Sediment Evaluation Team [RSET], 2018) and to the Portland Harbor Superfund Site remedial action levels (RALs) and Principal Threat Waste (PTW) thresholds provided in the Portland Superfund Site Record of Decision (ROD; United States Environmental Protection Agency [USEPA], 2017). Level 2B analyses were not completed as dredged sediments are planned to be disposed of upland. Sediment chemistry levels of nickel, 3+4 methylphenols, and polychlorinated biphenyls exceeded the Freshwater SL1 SLs in the dredge prism and Z-layer. No results exceeded Portland Harbor Superfund Site RALs or PTW thresholds.

Based on the results of the sediment characterization, sediments in the dredge prism (to -12 ft CRD) are not suitable for in-water placement in a freshwater environment. Some Z-layer sediments in the DMMU exhibited characteristics above relevant SLs and do not appear to be suitable for unconfined, aquatic exposure. However, Z-layer sediments within the 2024 dredge footprint exhibited characteristics below relevant SLs and appear to be suitable for unconfined, aquatic exposure.

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TABLE OF CONTENTS

EXECUTIVE SUMMARY ......................................................................................................................... I

1.0 INTRODUCTION ............................................................................................................................ 1-1

1.1 PROJECT OVERVIEW .......................................................................................................... 1-1

1.2 BACKGROUND ..................................................................................................................... 1-4

1.3 APPROACH ............................................................................................................................ 1-6

1.4 MANAGEMENT AREA RANK ............................................................................................ 1-8

1.5 REPORT ORGANIZATION ................................................................................................... 1-8

2.0 METHODS ....................................................................................................................................... 2-1

2.1 FIELD ACTIVITIES TEAM ................................................................................................... 2-1

2.2 SAMPLING METHODS......................................................................................................... 2-1

2.2.1 Sediment Coring Equipment....................................................................................... 2-1

2.2.2 Navigation and Vertical Control ................................................................................. 2-1

2.2.3 Collection of Sediment Cores ..................................................................................... 2-2

2.2.4 Decontamination ......................................................................................................... 2-2

2.2.5 Collection of Sediment Samples ................................................................................. 2-2

2.2.6 Chain-of-Custody ....................................................................................................... 2-3

2.2.7 Sample Collection Quality Assurance and Quality Control ....................................... 2-3

2.2.8 Deviations From SAP ................................................................................................. 2-4

2.3 PHYSICAL AND CHEMICAL ANALYSIS OF SEDIMENTS ............................................ 2-4

2.4 QUALITY ASSURANCE OBJECTIVES .............................................................................. 2-4

2.4.1 Physical and Chemical Analyses Quality Assurance ................................................. 2-5

3.0 RESULTS AND DISCUSSIONS .................................................................................................... 3-1

3.1 SAMPLE COLLECTION ....................................................................................................... 3-1

3.2 PHYSICAL CHARACTERIZATION .................................................................................... 3-1

3.3 CHEMICAL RESULTS AND ANALYSIS ............................................................................ 3-1

3.3.1 Metals ......................................................................................................................... 3-2

3.3.2 Pesticides .................................................................................................................... 3-2

3.3.3 Butyltins...................................................................................................................... 3-2

3.3.4 Polycyclic Aromatic Hydrocarbons ............................................................................ 3-2

3.3.5 Phthalates .................................................................................................................... 3-2

3.3.6 Phenols........................................................................................................................ 3-2

3.3.7 Miscellaneous Extractable Organic Compounds ........................................................ 3-3

3.3.8 Polychlorinated Biphenyls .......................................................................................... 3-3

3.3.9 Dioxins and Furans ..................................................................................................... 3-3

3.3.10 Other Analyses ........................................................................................................... 3-3

4.0 CONCLUSIONS .............................................................................................................................. 4-1

4.1 SUMMARY OF FINDINGS ................................................................................................... 4-1

4.2 RECOMMENDATIONS ......................................................................................................... 4-1

5.0 REFERENCES ................................................................................................................................. 5-1

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FIGURES (within text)

Figure 1 – Project Vicinity and Site Location ............................................................................................ 1-2 Figure 2 – 2022 Bathymetric Survey ......................................................................................................... 1-3 Figure 3 – Dredged Material Disposal Site Options .................................................................................. 1-5 Figure 4 – Sediment Sample Locations and Exceedances ......................................................................... 1-7

TABLES

Table 1 Sediment Core Locations Table 2 Sample Compositing Scheme Table 3a Composite Sediment Chemistry Results Table 3b Composite Sediment Chemistry Results – Dioxins/Furans Table 4a Discrete Sediment Chemistry Results Table 4b Discrete Sediment Chemistry Results – Dioxins/Furans Table 4c Discrete Sediment Chemistry Results – USEPA Analytes Table 4d Discrete Sediment Chemistry Results – cPAH Summation

APPENDICES

Appendix A Field Sediment Sampling Event Log Appendix B Sediment Core Logs Appendix C Photographic Log of Sediment Sampling Event Appendix D Chain-of-Custody Forms Appendix E Laboratory Chemistry Data Report Appendix F Data Validation Report

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ACRONYMS

µg/kg microgram per kilogram Apex Apex Laboratories LLC ASTM American Society for Testing and Materials BB&E BB&E, Inc.

CEU Civil Engineering Unit COC chain-of-custody CRD Columbia River Datum CY cubic yard(s) DDx dichlorodiphenyltrichloroethane and its derivatives Dixon Dixon Marine Services, Inc.

DMMU dredged material management unit ECSI Environmental Cleanup Site Information EDL estimated detection limit ft feet FTL field team leader HDPE high-density polyethylene LUST Leaking Underground Storage Tank mL milliliter MAR Management Area Rank MDL method detection limit mg/kg milligram per kilogram MRL method reporting limit MS/MSD matrix spike/matrix spike duplicate MSU Marine Safety Unit ND non-detect NFA No Further Action NFRAP No Further Remedial Action Planned NPL National Priorities List ODEQ Oregon Department of Environmental Quality PAH polycyclic aromatic hydrocarbon PCB polychlorinated biphenyl pg/g picogram per gram PSEP Puget Sound Estuary Protocols PSET Portland Sediment Evaluation Team PTW Principal Threat Waste QA/QC quality assurance/quality control RAL remedial action level ROD Record of Decision RSET Northwest Regional Sediment Evaluation Team SAP Sampling and Analysis Plan SCR Sediment Characterization Report SEF Sediment Evaluation Framework for the Pacific Northwest SEMS Superfund Enterprise Management System SLs Screening Levels SM Standard Methods TPH total petroleum hydrocarbon USACE United States Army Corps of Engineers USCG United States Coast Guard USEPA United States Environmental Protection Agency

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Distribution List

United States Coast Guard, Civil Engineering Unit - Oakland (USCG CEU) United States Army Corps of Engineers – Portland District (USACE) United States Environmental Protection Agency – Region 10 (USEPA) Portland Sediment Evaluation Team (PSET)

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1.0 INTRODUCTION

On behalf of the United States Coast Guard (USCG) Civil Engineering Unit (CEU) Oakland, BB&E, Inc.

(BB&E), has prepared this Sediment Characterization Report (SCR) to summarize the methods, observations, and findings from the Level 2A (physical and chemical) sediment sampling and evaluation activities for sediments planned to be dredged from the USCG Marine Safety Unit (MSU) Portland, located in Portland, Oregon (Figure 1). The sediment sampling event was conducted on 31 January 2024 in accordance with the Sampling and Analysis Plan for Maintenance Dredging at United States Coast Guard Station Marine Safety Unit Portland, Oregon (BB&E, 2023) and regulatory guidance. The work described in this SCR is also in accordance with the USCG CEU Oakland Project Scope for Project Serial Number 16890780 dated November 2021 for Contract Number 70Z05019DBBECPI02 Task Order 70Z08822FESDV0053 and United States Army Corps of Engineers (USACE) Permit No.

NWP-2013-721-1.

1.1 PROJECT OVERVIEW

Gradual deposition of sediments at the MSU Portland Facility requires the site to undergo maintenance dredging to maintain adequate channel and berth depths for USCG vessels that use the facility. The center of the entire 51,000 square foot maintenance dredge prism is at latitude 45.5705786 degrees north, longitude -122.7230837 degrees west. The project location is shown in Figure 1. Maintenance dredging was last conducted by the USCG in 2016 under USACE Permit Number NWP-2013-172.

Pending receipt of all necessary permits and authorizations, the USCG is proposing to perform maintenance dredging in 2024 of a portion of the maintenance dredge prism, using either mechanical clamshell method or a hydraulic method. This area is depicted as the “2024 dredge footprint” in Figure 2 and is comprised of an eastern area and a western area. These areas will be dredged to a depth of -10 feet (ft) Columbia River Datum (CRD) with a 2-foot overdepth (to -12 ft CRD) and 3:1 side slope. According to the pre-dredge bathymetric survey completed by Dixon Marine Services, Inc. (Dixon) on 17 November 2022, the total dredge volume for the main cut of the entire maintenance dredge prism to -10 ft CRD inclusive of the 2-foot overdepth (to -12 ft CRD) is approximately 3,000 CY. The USCG recognizes that these volumes will change by the proposed 2024 dredging action and anticipates a dredge volume of approximately 160 CY (to -12 ft CRD) in the western dredge area and approximately 400 CY in the eastern dredge area during the initial dredge event in 2024. The western dredge area covers approximately 690 square feet, and the eastern dredge area comprises approximately 4,200 square feet of the overall 51,000 square foot maintenance dredge prism. The Portland Sediment Evaluation Team (PSET) will be provided with revised volumes based on a pre-dredge survey within 30 days of the proposed dredging date. Figure 2 shows the conditions at USCG MSU Portland based on the bathymetric survey completed by Dixon on 17 November 2022. Pre-dredge sediment elevations within the proposed 2024 dredge footprint area range from 4 ft CRD to -27 ft CRD based on the 2022 bathymetric survey (Figure 2).

Representative sediments from the dredge prism and post-dredge surface were evaluated in accordance with the Sampling and Analysis Plan (SAP; [BB&E, 2023]) to determine the potential effects the dredge material would have on the chemical and physical components of the environment during the dredging process and exposure of the post-dredge surface. The USCG understands that no dredging may occur until final episode approval is obtained from the appropriate regulatory agencies.

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Figure 1 – Project Vicinity and Site Location

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Figure 2 – 2022 Bathymetric Survey

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The purpose of this SCR is to present the results from the Level 2A analyses of the sediments to be dredged and exposed at the MSU Portland Facility. The Level 2A testing included physical and chemical analyses of the sediment designed to allow PSET to make a suitability determination regarding the exposure of dredged material during dredging and exposure of the post-dredge surface. The Level 2A physical and chemical parameters analyzed included grain size, total solids, total volatile solids, total organic carbon, metals, polycyclic aromatic hydrocarbons (PAHs), phthalates, phenols, miscellaneous extractable organic compounds, pesticides, polychlorinated biphenyls (PCBs) as total Aroclors, butyltins, and total petroleum hydrocarbon (TPH), as detailed in the Sediment Evaluation Framework for the Pacific Northwest (SEF;

Northwest Regional Sediment Evaluation Team [RSET], 2018). Dioxins/furans were also analyzed based on known contamination in the vicinity of the dredging area. As required by the USEPA Region 10, discrete Z-layer samples were collected and analyzed for the Portland Harbor Superfund Site ROD (USEPA, 2017) Table 21 contaminants to allow the USEPA to make a determination for allowing the exposure of the post-dredge surface. Dredged sediment is expected to be disposed of at the Hillsboro Landfill located in Hillsboro, Oregon. The Hillsboro Landfill is located approximately 13.2 miles southwest of MSU Portland (Figure 3).

1.2 BACKGROUND

MSU Portland is located in the Swan Island Basin of the Willamette River in Portland, Multnomah County, Oregon (Figure 1). MSU Portland is located in Township 1 North, Range 1 East, Willamette Meridian, near Willamette RM 7.5. MSU Portland was established in 1973 and has an area of responsibility that includes Oregon, Southern Washington, and Western Idaho. MSU Portland is responsible for all vessel inspections and promoting marine safety issues. These include marine safety, port security, marine environmental response, maritime law enforcement, and search and rescue.

The waterfront area located near the proposed dredge area consists of floating docks, piers, a railroad track, a college campus, a Navy Reserve center, a shipyard, and the USCG facility that includes a large impervious parking lot. There is one stormwater outfall located in the vicinity of the authorized dredged area, located approximately 0.3 miles southeast of the site in the Swan Island Basin (Figure 2). Pre-dredge sediment elevations within the proposed dredge footprint area range from 4 ft CRD to -27 ft CRD based on the 2022 bathymetric survey (Figure 2).

USCG MSU Portland is not listed on the USEPA National Priorities List (NPL); however, the facility is located within the Portland Harbor Superfund Site and is listed on the USEPA Superfund Enterprise Management System (SEMS) database as an archived site with the status of No Further Remedial Action Planned (NFRAP). The MSU Portland Facility is also listed on the Oregon Department of Environmental Quality (ODEQ) Environmental Cleanup Site Information (ECSI) database and Leaking Underground Storage Tank (LUST) database with ECSI ID 1388 and LUST File No. 26-96-0002. A No Further Action (NFA) determination was provided by the ODEQ on 22 August 1997 (ODEQ, 1997) for the LUSTs, and the ODEQ LUST database lists the site as closed. The ODEQ ECSI listing references soil, groundwater, sediment, and stormwater investigations that have occurred at the facility between 2000 and 2018. The site investigative status is listed as “Contamination Suspected” and does not indicate that the site is closed.

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Figure 3 – Dredged Material Disposal Site Options

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1.3 APPROACH

The proposed dredge area was evaluated through one composite sample and one composite Z-layer sample, collected from four pre-determined coring stations (shown on Figure 4), as identified in the SAP (BB&E, 2023). Each proposed coring station was sampled to the proposed dredge depth, plus a 2-foot overdepth (to -12 ft CRD) and 2-foot Z-layer (-12 to -14 ft CRD), using vibracore equipment supplied and operated by Dixon. Actual coring station locations were selected in the field during sampling activities based on the deposition shown in the November 2022 bathymetric survey (Figure 2), field conditions, equipment limitations, and best professional judgment. As shown in Figure 4, actual coring stations were closely aligned with the proposed locations that had been presented in the SAP (BB&E, 2023) and subsequent revisions provided to PSET.

A total of four sediment subsamples were collected from the dredge prism (to -12 ft CRD) at four coring station locations, designated as MSUP-01, MSUP-02, MSUP-03, MSUP-04 (MSUP = MSU Portland).

These subsamples were then homogenized into a single composite sample from which MSUP-COMP and MSUP-COMP-DUP (dredge prism duplicate) samples were collected for Level 2A physical and chemical analyses.

A total of three sediment subsamples were collected from the 2-foot Z-layer immediately below the 2-foot overdepth allowance (-12 ft to -14 ft CRD) at three of the four coring stations (MSUP-01, MSUP-03, and MSUP-04; penetration and recovery issues prevented the collection of a Z-layer sample from MSUP-02, as further discussed in Section 2.2.8). As required by the USEPA Region 10, discrete Z-layer samples were collected and analyzed for the Portland Harbor Superfund Site ROD (USEPA, 2017) Table 21 contaminants. The three Z-layer sediment subsamples were also homogenized into a single composite sample designated as MSUP-ZL for Level 2A physical and chemical testing. Table 1 presents the location information for each of the samples and Table 2 outlines the compositing scheme with actual core lengths and depths of all coring stations.

Prior to the compositing of the sediment, approximately 500 milliliters (mL) of dredge prism sediment from each of the four coring stations was archived to allow for additional chemical reanalysis, if necessary (archived samples were stored frozen at Apex Laboratories LLC [Apex]). The Z-layer samples were processed and archived in a similar fashion for potential future analysis, if required, except for MSUP-02 where no Z-layer sediment was collected.

The objective of the coring station selection and the subsequent compositing design is to provide samples that represent, as accurately as possible, the DMMU by analyzing the physical and chemical characteristics of the sediments removed. The final locations of coring stations, as well as any rejected cores collected, are included in Figure 4.

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Figure 4 – Sediment Sample Locations and Exceedances

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1.4 MANAGEMENT AREA RANK

The project Management Area Rank (MAR) is assigned using available past sampling data, recency of past sampling data, and potential sources of contamination.

Local sources of contamination include heavy use by vehicles, watercraft, and people, particularly during the summer; potential fuel spills while fueling vessels; and stormwater runoff from impervious surfaces near the marina. Petroleum products released from underground storage tanks previously located at MSU Portland and various contaminants released from nearby historical sites in the Swan Island Basin are considered potential sources of contamination.

The MSU Portland maintenance dredge footprint (DMMU 1) has been assigned a moderate MAR based on the prior suitability determination memorandum and potential sources of contamination at and around MSU Portland and the current use of MSU Portland as an active marina and USCG docking area. The project MAR dictates the maximum volume of material that can be included in a single DMMU. A moderate MAR has a maximum volume threshold of 40,000 CY, based on Table 4-1 of the SEF (RSET, 2018).

1.5 REPORT ORGANIZATION

This report presents the results of sediment sampling conducted as part of maintenance dredging at the MSU Portland Facility. The remaining sections of this report are organized as follows:

• Section 2.0 Methods

• Section 3.0 Results and Discussions

• Section 4.0 Conclusions

• Section 5.0 References

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2.0 METHODS

The following sections summarize the methods used to conduct sediment sampling as well as the results of Level 2A physical and chemical analyses. All sediment sampling collection and analysis methods followed guidelines set forth by the Evaluation of Dredged Material Proposed for Discharge in Waters of the U.S. – Testing Manual (Inland Testing Manual), (USEPA and USACE, 1998), the SEF (RSET, 2018), and those specified in the SAP (BB&E, 2023), except where noted.

2.1 FIELD ACTIVITIES TEAM

A field technician from BB&E along with a Field Team Leader (FTL) from Dixon collected and prepared core samples that were delivered to the designated laboratory for analysis. Jeff Haran served as the FTL for Dixon, and Will Laughner served as the field technician for BB&E. The SAP Project Manager and the FTL provided input in all decisions regarding quality assurance/quality control (QA/QC) and ensured proper protocols for sample collection, preservation, holding times, transport, and sample control were exercised.

All coring equipment was provided by Dixon.

2.2 SAMPLING METHODS

BB&E conducted sediment sampling at MSU Portland on 31 January 2024. Samples from the maintenance dredge footprint (DMMU 1) were collected using a vibracore device onboard the vessel Walter Marie, which was operated by Dixon based out of Inverness, California. All necessary precautions were taken to ensure personnel and equipment safety and to prevent contamination of sediment core samples. The samples were processed and composited onsite and submitted to Apex for Level 2A physical and chemical analyses.

The field sediment sampling event log and photographic log of the sediment sampling event are provided in Appendix A and Appendix C, respectively.

2.2.1 Sediment Coring Equipment

Sediment cores were collected by Dixon using vibracore equipment supplied by Dixon. The vibracore was deployed from the Walter Marie sampling vessel using a purpose-built frame. Cellulose acetate butyrate core liners with an inner diameter of 3.6 inches were used with stainless steel core catchers.

2.2.2 Navigation and Vertical Control

Location control was the responsibility of the boat captain and was accomplished using a global positioning system that used United States Government Wide-Angle Augmentation System differential correction data to identify each coring station. The navigation system was calibrated to a known survey monument in the project area and was used to guide the vessel to predetermined coring stations (Figure 4).

Upon locating the sampling position, station water depth was measured using an on-board lead line, and tidal elevation was determined relative to harbor datum CRD. The tidal elevation was subtracted from the measured depth to determine the sediment surface elevation relative to CRD. All vertical elevations were reported to the nearest 0.1 foot relative to 0-foot CRD as shown in Table 1.

The following information was recorded on sediment core logs (Appendix B):

• Time and Date

• Horizontal location (NAD 83, Oregon North Zone, Feet)

• Measured water depth of station

• Tide readings and tide corrections

• Estimated mudline elevation (CRD)

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2.2.3 Collection of Sediment Cores

All sediment cores were collected using vibracore equipment aboard a vessel supplied and operated by Dixon. Before the collection of each sample core, the vibracore was decontaminated with water and phosphate-free Liquinox and loaded with a new, clean core barrel liner.

A 3.75-inch diameter core was used to ensure that there was enough material for all required tests. Cores were collected to at least -14 ft CRD to ensure sediment from the entire sampling interval was collected.

The 2 ft of sediment from the Z-layer was removed from each core section and temporarily stored in a separate container. Samples were collected from the respective intervals without linear core correction.

Sediment retrieved below -14 ft CRD was discarded. Upon completion of core penetration at each station, the position coordinates were recorded, and the sampler recovered.

Once the core was on deck, the soft liner was extracted from the corer barrel. The core was examined to determine compliance with acceptability criteria as follows:

1. The core penetrated and retained material to the core length proposed in the SAP (BB&E, 2023);

2. The core material did not extend out of the top of the core tube or contact any part of the sampling apparatus at the top of the core tube;

3. There were no obstructions in the cored material that may have blocked the subsequent entry of sediment into the core tube resulting in an incomplete core collection;

4. Core was collected within the acceptable radius (within 25 ft) of the proposed location; and

5. Core recovery was acceptable (at least 75 percent recovery).

Percent Core Recovery = (Recovered Sediment Length / Penetration Length) x 100

Once proper depth was achieved, the soft liner was sealed and labeled in accordance with the SAP (BB&E, 2023) onboard the sampling vessel. Sediment cores were then returned to the shore to be logged, processed, and sampled. Any excess core material was returned to the basin within the dredge footprint.

2.2.4 Decontamination

All sampling equipment that came in contact with collected sediments was decontaminated between stations using the following procedures:

1. Rinsed with ambient water and washed with a scrub brush until free of sediment;

2. Washed with phosphate-free Liquinox as needed; and

3. Rinsed with de-ionized water.

2.2.5 Collection of Sediment Samples

Sediment cores were collected to provide a representative sample of the sediments within the proposed dredge footprint (DMMU 1), which included the dredge prism (to -12 ft CRD) and the Z-layer (-12 to -14 ft CRD). Compositing and homogenization of the core sediments was performed onsite based on field conditions before transport to the laboratory. A tiered-testing approach was used to ensure that all required samples were collected and archived in the event further testing was deemed necessary. Table 2 presents the sample intervals for each core. Several cores at locations MSUP-01, MSUP-02, and MSUP-04 were rejected based on field conditions that are further discussed in Section 3.1.

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2.2.5.1 Dredge Prism

The dredge prism samples comprised material to the design depth plus the 2-foot overdepth (to -12 ft CRD) and were collected from four individual coring stations located within the MSU Portland maintenance dredge prism (Figure 4).

For each sample core, sediment was scraped from the center portion along the entire core length representing the dredge prism and placed into a decontaminated stainless-steel mixing bowl or high-density polyethylene (HDPE) container. The sample was homogenized manually until both color and texture were uniform. From the four individual core samples, one composite was made of the material to the design depth plus the 2-foot overdepth (-12 ft CRD). The composite sample was made by combining equal aliquots of sediments from the four individual sampling locations into one sample. In total, one composite dredge prism sample was created for the DMMU. The sediment was homogenized manually as mentioned above.

Appropriate volumes of the site composite sample were collected into sample containers for shipment to the analytical laboratory in accordance with the size and container type provided by Apex. Additionally, approximately 500 milliliters (mL) of sediment was collected from each of the four sample cores. The composite sample was analyzed for chemical and physical analysis following sample collection. One duplicate dredge prism composite sample and one matrix spike/matrix spike duplicate (MS/MSD) dredge prism composite sample were also collected.

Prior to the compositing of the sediment, approximately 500 mL of sediment was collected from each of the four sample cores and was archived to allow for additional chemical analyses, if necessary (archived samples were stored frozen at Apex). The Z-layer samples were processed in a similar fashion and archived for potential future analysis, if required.

2.2.5.2 Z-Layer

The Z-layer samples were collected from the first 2 ft below the dredge prism (i.e., the -12 to -14 ft CRD interval) from three of the four coring stations located within the MSU Portland maintenance dredge footprint (Figure 4). Penetration issues at location MSUP-02 did not allow for the collection of Z-layer sediment. The Z-layer from each individual core was homogenized manually until both color and texture were uniform.

As required by the USEPA Region 10, discrete Z-layer samples were collected and analyzed for the Portland Harbor Superfund Site ROD (USEPA, 2017) Table 21 contaminants (PCBs as total Aroclors, pesticides, PAHs, and dioxins/furans). The material from the three individual Z-layer samples was then composited to create one composite Z-layer sample. The Z-layer samples were analyzed concurrently with the dredge prism composite samples.

Prior to the compositing of the Z-layer sediment, approximately 500 mL of Z-layer sediment from each of the three coring stations was archived to allow for additional chemical reanalysis, if necessary (archived samples were stored frozen at Apex). No archived samples have been reanalyzed.

2.2.6 Chain-of-Custody

Chain-of-custody (COC) procedures followed SEF protocols for all samples throughout the collection, handling, and analysis activities. The BB&E SAP field technician was responsible for final sample inventory, maintenance-of-sample custody documentation, and completion of COC forms before transferring samples to the analytical laboratory. COC forms are included as Appendix D.

2.2.7 Sample Collection Quality Assurance and Quality Control

QA/QC objectives for sample collection are designed to preserve sample integrity by facilitating proper cleaning, collection, labeling, COC, and shipping techniques. Sampling equipment was either new or

MSU Portland Maintenance Dredging 2-4 decontaminated prior to each sampling effort and was decontaminated between sampling locations to avoid cross contamination. Logbooks were maintained by field personnel to document local conditions and any deviations from sampling protocol. Samples were collected into glass containers. All personnel handling samples wore disposable nitrile gloves and other personal protective equipment. COC records were maintained in the field and through the shipment of the samples, documenting the sampling date, time, volume, and other pertinent information. Samples were clearly labeled with station identification designations using waterproof pens. Samples were stored on ice in the dark and dropped off or shipped to the testing laboratories as quickly as possible.

2.2.8 Deviations From SAP

In the SAP (BB&E, 2023), the vertical datum boundaries of the dredge prism and Z-layer were incorrectly converted from mean lower low water values and therefore incorrectly presented in the SAP. The dredge depths are correctly outlined in this document with the dredge depth, plus a 2-foot overdepth to -12 ft CRD and the 2-foot Z-layer from -12 to -14 ft CRD. BB&E alerted PSET to the change during the pre-sampling call on 08 January 2024 and followed up via email with revised figures, volume estimates, and dredge depths on 23 January 2024. PSET provide approval of the change via email on 23 January 2024.

After submittal of the SAP, a revised 2024 dredge footprint was proposed at a smaller area of the entire maintenance dredge prism. On the advisement of PSET, the coring station MSUP-02 location was relocated within the 2024 dredge prism.

During the sampling effort on 31 January 2024, three coring attempts were made at the MSUP-02 location, and insufficient penetration and recovery were encountered during each attempt. After the third attempt, the PSET Lead was contacted by telephone to determine next steps, and it was determined that the core with the most recovery should be incorporated into the dredge prism composite sample (MSUP-COMP) and no Z-layer sample should be collected, as the Z-layer sediment was not reached. Accordingly, some collected sediment was included in MSUP-COMP and MSUP-COMP-DUP; however, no Z-layer sediment was collected from the coring station.

A total of seven cores were collected that did not have sufficient penetration and/or recovery (two cores from MSUP-01 and MSUP-04 and three cores from MSUP-02, one of which was still collected). While it was stated originally in the SAP that all cores that were collected would be logged, it was discussed with the PSET Lead and determined that logging of unsampled cores would be unnecessary. Due to time constraints, these cores were not logged.

2.3 PHYSICAL AND CHEMICAL ANALYSIS OF SEDIMENTS

Samples for physical and chemical analyses (Level 2A) were delivered to Apex in Tigard, Oregon. The lab is State of Oregon-certified and USCG-approved. Physical and chemical analytical methods utilized by Apex are documented in Section 2.4.1.3, Table 3a, Table 3b, and Table 4a through Table 4d.

2.4 QUALITY ASSURANCE OBJECTIVES

Field staff adhered to the decontamination procedures as prescribed within the SAP (BB&E, 2023) to minimize cross-contamination during sediment sampling.

A field duplicate was collected during sampling from the composite sample for Level 2A analysis. The analytical laboratory prepared a matrix spike and a MS/MSD sample on the parent sample for analysis.

Samples were maintained according to method holding times and temperatures. A written Level 2 laboratory report was provided by Apex documenting the analysis and data. The report is provided in Appendix E.

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QA procedures used for sediment characterization and testing were consistent with methods described in USEPA and USACE (1991, 1995, and 1998), USEPA (1998a, 1998b), validation procedures inclusive of analytical results, results of laboratory QA/QC samples, protocols used during analyses, deviations from any COC procedures, protocol deviations, and the location and availability of data and archived samples.

The methods employed in this sediment sampling and characterization report are detailed in standard guides (e.g., Standard Methods, American Society for Testing and Materials [ASTM], USEPA, etc.) and Laboratory Test Conditions and Acceptability Criteria, included in the SAP (BB&E 2023).

2.4.1 Physical and Chemical Analyses Quality Assurance

An independent review of the chemical and physical laboratory data included consultation with guidelines set forth in the USEPA National Functional Guidelines for Organic Superfund Methods Data Review (USEPA, 2020a) and USEPA National Functional Guidelines for Inorganic Superfund Methods Data Review (USEPA, 2020b)

The January 2024 analytical data, including qualified data, were found to be acceptable for their intended use based on the data review results, including evaluation of precision/accuracy (spiked samples), representativeness (blank and duplicate samples), comparability (collection and reporting techniques), and completeness (defined to be the percentage of analytical results judged to be valid). Completeness for the January 2024 data set was greater than 100 percent. The data quality assessment report is presented as Appendix F.

2.4.1.1 Accuracy

Accuracy estimates were based on analyses of lab blanks, analytical recoveries of matrix spikes of test samples and of laboratory control materials, and analysis of certified reference material and/or laboratory duplicates. Results from spikes and/or reference materials are reported as “percent recovery” and are determined by comparing the measured analyte concentrations of the standard reference materials, laboratory control materials, or matrix spikes to the “true value.” Percent recovery is reported along with the corresponding acceptance ranges. When applicable, surrogate compounds were spiked into each sample and surrogate percent recovery was reported along with the corresponding control limits. Laboratory control spikes were added before processing the sample and carried through the entire analytical procedure.

2.4.1.2 Precision

Precision was estimated by analyzing duplicate samples and matrix spike duplicate samples. Results from duplicate analyses of the actual test samples may also indicate homogeneity of the sample matrix. Relative percent differences were calculated for all duplicate samples or spikes and were reported along with acceptance ranges.

2.4.1.3 Analytical Methods

Sample analyses were performed using the following methods:

• EPA 6020B Total metals

• EPA 7471B Total mercury

• EPA 8270E Pesticides

• EPA 8270E Selected Ion Monitoring Butyltin Ion

• EPA 8270E Semi-Volatile Organic Compounds, including PAHs

• EPA 8082A PCBs

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• EPA 1613 Dioxins and furans

• NWTPH-Dx Northwest Total Petroleum Hydrocarbons (diesel / residual oil hydrocarbons)

• Puget Sound Estuary Protocols (PSEP) 1986 / Standard Methods (SM) 2540G Total solids and Total volatile solids

• PSEP / SM 5310B MOD Total organic carbon

• ASTM D-422 Grain size modified

2.4.1.4 Sample Tracking

Sample COC sheets, sample receipt logs, sample holding, and sample labeling procedures were audited weekly by the laboratory’s QC unit.

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3.0 RESULTS AND DISCUSSIONS

The following sections summarize the results of the Level 2A physical and chemical analyses conducted in accordance with the SAP (BB&E, 2023). Table 3a, Table 3b, and Table 4a through Table 4d present the complete results of the physical and chemical analyses for composite samples and includes the duplicate sample for reference. All original laboratory reports from Apex are presented in Appendix E.

3.1 SAMPLE COLLECTION

As described in Section 2, one dredge prism composite sediment sample (MSUP-COMP) was collected and comprised of the homogenization of four individual coring stations. A composite Z-layer sample was collected from the Z-layer of three of the four coring stations (MSUP-ZL). Additionally, discrete Z-layer samples from three of the four coring stations were collected and analyzed for select analytes from Table 21 of the Portland Harbor Superfund Site ROD. These samples were submitted to Apex for physical and chemical analyses. A detailed description of each core is provided in the core logs included as Appendix B. No stratified layers or evidence of impacts (i.e., staining or odors) were observed that warranted additional testing. The target core length was achieved at three of the four sampling locations. Insufficient penetration and recovery was encountered at MSUP-02. Accordingly, some collected sediment was included in MSUP-COMP and MSUP-COMP-DUP; however, no Z-layer sediment was collected. The COC documentation for the collected samples is provided in Appendix D.

Several cores with insufficient penetration and/or recovery were encountered at locations MSUP-01, MSUP-02, and MSUP-04. Due to time constraints, and after discussion in the field with the PSET Lead, it was determined that there was no need to log these sediment cores.

3.2 PHYSICAL CHARACTERIZATION

The dredge area composite samples (MSUP-COMP, MSUP-COMP-DUP, and MSUP-ZL) were analyzed for the Level 2A physical and chemical parameters listed in Section 1.1 and shown in Table 3a and Table 3b. Z-layer discrete samples were analyzed for physical and chemical parameters shown in Table 4a through Table 4d. The methods and detection limits specified for the analyses correspond to those specified in the SAP (BB&E, 2023) with the exception of deviations noted in Section 2.2.8. The dredge prism samples were primarily comprised of sand (approximately 68 percent) with a small number of fines (approximately 24 percent silt and 2 percent clay) and minimal gravel (approximately 5 percent). The Z-layer sample was similarly primarily comprised of sand (approximately 72 percent) with smaller amounts of fines (approximately 19 percent silt and 5 percent clay) and minimal gravel (approximately 4 percent).

3.3 CHEMICAL RESULTS AND ANALYSIS

The results of sediment chemical analyses are summarized below for the samples and are presented in Table 3a and Table 3b. Where applicable, the results are compared to the following guideline values:

• Freshwater Benthic Toxicity SL1 and Bioaccumulation SLs (RSET, 2018)

• Portland Harbor Superfund Site – Site Wide remedial action levels (RALs) – (discrete Z-layer samples only) (USEPA, 2017)

• Portland Harbor Superfund Site – Principal Threat Waste (PTW) Thresholds – (discrete Z-layer samples only) (USEPA, 2017)

The Freshwater Benthic Toxicity SL1 Screening Levels (SLs) correspond to a concentration below which adverse effects to benthic communities would not be expected. Exceedances of a guideline value do not preclude a sample from being suitable for unconfined, aquatic disposal determination, but rather indicates more information is needed for the agencies to make a determination of suitability for in-water placement

MSU Portland Maintenance Dredging 3-2 or exposure. The SL1 SLs will be used by PSET to determine the post-dredge surface is suitable for unconfined aquatic exposure.

The Portland Harbor Superfund Site RALs and PTW thresholds will be used by the USEPA to determine the post-dredge surface is suitable for unconfined aquatic exposure.

3.3.1 Metals

Nickel was detected at concentrations exceeding the Freshwater SL1 SL (26 milligrams per kilogram [mg/kg]) in MSUP-COMP (27.0 mg/kg), MSUP-COMP-DUP (50.7 mg/kg), and MSUP-ZL (28.3 mg/kg).

The MSUP-COMP and MSUP-ZL samples were detected below the ODEQ background level for nickel (47 mg/kg). All other metals analyzed in MSUP-COMP and MSUP-ZL were either non-detect (ND) or below the Freshwater SL1 SLs. All method reporting limits (MRLs) for metals analysis were below the Freshwater SL1 SLs.

3.3.2 Pesticides

All pesticides analyzed were either ND or below the Freshwater SL1 SLs in all samples. All MRLs for pesticides analysis were below the Freshwater SL1 SLs.

Dichlorodiphenyltrichloroethane and its derivatives (DDx) results for all discrete Z-layer samples were detected below the USEPA Site Wide RAL (160 micrograms per kilogram [μg/kg]) and PTW Threshold (7,050 μg/kg) for the Portland Harbor Superfund Site.

3.3.3 Butyltins

All butyltins analyzed were either ND or below the Freshwater SL1 SLs in all samples. All MRLs for butyltins analysis were below the Freshwater SL1 SLs.

3.3.4 Polycyclic Aromatic Hydrocarbons

Total PAHs in all samples were detected below the Freshwater SL1 SL, and all MRLs for PAHs analysis were below the Freshwater SL1 SLs.

Naphthalene results for all discrete Z-layer samples were detected below the USEPA PTW Threshold (7,050 μg/kg) for the Portland Harbor Superfund Site. Total PAH results for all discrete Z-layer samples were detected below the USEPA Site Wide RAL (30,000 μg/kg) for the Portland Harbor Superfund Site.

Carcinogenic PAH results for all discrete Z-layer samples were detected below the USEPA PTW Threshold (774,000 μg/kg) for the Portland Harbor Superfund Site.

3.3.5 Phthalates

All phthalates analyzed were either ND or below the Freshwater SL1 SLs in all samples. Aside from di-n-octyl phthalate, all MRLs for phthalates were below the Freshwater SL1 SLs. Di-n-octyl phthalate had an MRL of 39.8 μg/kg in the MSUP-03ZL sample and 42.8 μg/kg in the MSUP-04ZL sample, which exceeded the Freshwater SL1 SL of 39 μg/kg. Both of these samples were collected outside of the 2024 dredge footprint. Despite the MRL exceeding the SL, di-n-octyl phthalate was reported as ND, and its method detection limits (MDLs) were below the SL. The MDL for MSUP-03ZL was 33.0 μg/kg and the MDL for MSUP-04ZL was 38.9 μg/kg. Accordingly, the result is not considered to have exceeded the Marine SL1 SL, per SEF (RSET, 2018) guidance. These results are included in Table 3a and Table 4a.

3.3.6 Phenols

Concentrations of 3+4-Methylphenols(s) detected in MSUP-COMP (338 μg/kg), MSUP-COMP-DUP (292 μg/kg), MSUP-03ZL (342 μg/kg), and MSUP-04ZL (1,150 μg/kg) exceeded the Freshwater SL1 SL of 260

MSU Portland Maintenance Dredging 3-3 μg/kg. The exceedances in Z-layer samples were collected outside of the 2024 dredge footprint. No other phenols analyzed were detected at concentrations exceeding Freshwater SL1 SLs in any of the samples. All phenols analyzed in all other samples were either ND or below the Freshwater SL1 SLs. All MRLs for phenols analyzed were below the Freshwater SL1 SLs.

3.3.7 Miscellaneous Extractable Organic Compounds

All miscellaneous extractable organic compounds analyzed were either ND or below the Freshwater SL1 SLs. All MRLs for miscellaneous extractable organic compounds were below the Freshwater SL1 SLs.

3.3.8 Polychlorinated Biphenyls

There are no Freshwater SL1 SLs for individual PCB Aroclors, only for PCB as total Aroclors. The summation of PCB Aroclors detected in MSUP-COMP-DUP (130.2 μg/kg) exceeded the Freshwater SL1 SL for Total Aroclors (110 μg/kg); however, the summation of PCB Aroclors detected in native sample MSUP-COMP (90.0 μg/kg) did not exceed the Freshwater SL1 SL. The summations of PCB Aroclors detected in MSUP-01ZL (6.36 μg/kg), MSUP-03ZL (35.1 μg/kg), and MSUP-04ZL (ND) did not exceed the Freshwater SL1 SL. The summation of PCBs as total Aroclors detected in MSUP-COMP (90.0 μg/kg), MSUP-COMP-DUP (130.2 μg/kg), and MSUP-03ZL (35.1 μg/kg) exceeded the PSET bioaccumulation SL of 22 μg/kg, as derived from the ODEQ Sediment Bioaccumulation Screening Level Values for freshwater fish. All MRLs were below the Freshwater SL1 SL for Total Aroclors.

PCBs as total Aroclors results for all discrete Z-layer samples were detected below the USEPA Site Wide RAL (75 μg/kg) and PTW Threshold (200 μg/kg) for the Portland Harbor Superfund Site.

3.3.9 Dioxins and Furans

The 17 congeners of dioxins and furans results were summed using the two summation methods outlined in Section 6.1.2 of the SEF (RSET, 2018), where ND values are either counted as zero or one-half of the estimated detection limit (EDL). Where ND = ½EDL, the dioxin/furan summation for MSUP-COMP and MSUP-COMP-DUP were 6.88 picograms/gram (pg/g) and 6.08 pg/g, respectively.