OregonSlough_ShallowDraft_FNC_2A SDM_09082021.pdf

EPA-Region 10 Water Division, Wetlands and Oceans Section 08 September 2021

Memorandum for: U.S. Army Corps of Engineers – Portland District, Operations Division, Channels and Harbors, Waterways Maintenance Section (CENWP-ODN-W, Stokke), Oregon Slough Downstream Shallow Draft Federal Navigation Channel (miles 1.5 to 3.8) in Portland, Multnomah County, Oregon.

Subject: Portland Sediment Evaluation Team (PSET) Level 2A dredged material suitability determination for the U.S. Army Corps of Engineers - Portland District’s (USACE) operations and maintenance (O&M) dredging for the Oregon Slough Downstream (OSD) Shallow Draft Federal Navigation Channel (FNC) in the Columbia River at river mile (RM) 101.4 to 104.6 (project mile 1.5 to 3.8).

Introduction: Per the May 2018 Sediment Evaluation Framework for the Pacific Northwest (SEF)1, this suitability memorandum (SDM) documents the consensus of the PSET agencies regarding the suitability of the OSD shallow draft FNC dredged material for unconfined, aquatic disposal and suitability of the post-dredge surface for unconfined, aquatic exposure. The PSET reviewed the December 2020 “Sediment Characterization: Oregon Slough Downstream Shallow Draft Channel (Miles 1.5 to 3.8), Multnomah County, Oregon” (2020 SQER)2 and the August 2021 “Supplemental Sediment Characterization: Oregon Slough Downstream Shallow Draft Channel (Miles 1.5 to 3.8), Multnomah County, Oregon” (2021 SQER)3, prepared by ANAMAR for the USACE’s Sediment Quality Team (SQT). Sediment chemical testing results are summarized in the SQER; chemical analytical results were compared to the freshwater benthic toxicity screening levels (SEF SLs) published in the 2018 SEF. The PSET also used Oregon DEQ’s sediment screening level value (SLV) for freshwater fish to evaluate PCBs and dioxins and furans4.

Suitability Summary:

Dredge Prism (DP) Sediments: ☒Suitable ☐Unsuitable Post-Dredge Surface (PDS): ☒Suitable ☐Unsuitable

Reviewers: The PSET agencies include the USACE, U.S. Environmental Protection Agency – Region 10 (EPA), National Marine Fisheries Service (NMFS), U.S. Fish and Wildlife (USFWS), Washington Department of Ecology (Ecology), and Oregon Department of Environmental Quality (ODEQ). Table 1 lists the PSET’s review timeline for this project. Reviewers included:

1 U.S. Army Corps of Engineers, U.S. Environmental Protection Agency, Washington Department of Ecology, Washington Department of Natural Resources, Oregon Department of Environmental Quality, Idaho Department of Environmental Quality, National Marine Fisheries Service, and U.S. Fish and Wildlife Service. 2018. Sediment Evaluation Framework for the Pacific Northwest. Published May 2018, by the U.S.

Army Corps of Engineers, Northwestern Division, 183 pp with Appendices.

2 U.S. Army Corps of Engineers (USACE) – Portland District. 2020. Sediment Characterization Oregon Slough Downstream Shallow Draft Channel (Miles 1.5 to 3.8), Multnomah County, Oregon. Prepared by ANAMAR, December 2020. 25 pp with Maps, Tables, and Appendices.

3 USACE – Portland District. 2021. Supplemental Sediment Characterization Oregon Slough Downstream Shallow Draft Channel (Miles 1.5 to 3.8), Multnomah County, Oregon. Prepared by ANAMAR, August 2021. 27 pp with Maps, Tables, and Appendices 4 Oregon Department of Environmental Quality. 2007. Guidance for Assessing Bioaccumulative Chemicals of Concern in Sediment. Updated April 3, 2007 by ODEQ Environmental Cleanup Program, 18 pp with Appendices.

☒ James Holm (USACE, Lead) ☒ Bridgette Lohrman (EPA, Co-Lead) ☒ Pete Anderson (ODEQ) ☒ Laura Inouye (Ecology) ☒ Dominic Yballe (USACE) ☒ Tom Hausmann (NMFS) ☒ Jeremy Buck (USFWS)

PSET/SEF Conditions:

☒ Data Recency Expiration – Based on a “Low” rank, the data recency for sediments in the Oregon Slough Downstream Shallow Draft Federal Navigation Channel expires in May 2028.

Table 1. Review Timeline

Draft Sampling and analysis plan (SAP) submitted to PSET 1 September 2020 SAP revisions requested by PSET 4 September 2020 Revised SAP5 submitted 5 September 2020 Revised SAP approved by PSET6 10 September 2020 Sampling date(s) 11-13 September 2020 Draft SQER submitted to PSET 11 December 2020 Sonic drill sampling concept submitted to PSET 19 January 2021 Supplemental SAP submitted to PSET7 29 January 2021 Supplemental SAP approved by PSET8 25 February 2021 Sonic drill sampling date(s) 10-12 May 2021 Supplemental SQER submitted to PSET 24 August 2021 Suitability Determination Memorandum (SDM) issued by PSET 08 September 2021 Management area ranking Low Recency of data May 2028 (7 years)

Federal Regulatory Authorities:

☒ Section 10, Rivers and Harbors Act ☒ Section 404, Clean Water Act (CWA) ☒ Section 401, CWA ☒ Section 7, Endangered Species Act ☒ Section 305 of the Magnuson-Stevens Act ☒ Fish and Wildlife Coordination Act ☐ Section 103, Marine Protection, Research and Sanctuaries Act ☐ Comprehensive Environmental Response, Compensation, and Liability Act

Project Description: Table 2 provides a summary of the dredging project details for the OSD shallow draft FNC. Maintenance dredging is needed to provide navigation access.

5 USACE – Portland District. 2020. Oregon Slough Downstream Shallow Draft Channel (mile 1.5 to 3.8) Multnomah County, Oregon, Sediment Sampling and Analysis Plan (v2.1). Prepared by SQT, 5 September 2020. 29 pp with Attachment.

6 Portland Sediment Evaluation Team (PSET). 2020. Oregon Slough Downstream FNC – SAP Approval. Email issued by B. Lohrman (EPA) for PSET, 10 September 2020. 3 pp with Attachment.

7 USACE – Portland District. 2021. Supplemental Sampling and Analysis Plan (SSAP) for Level 2A and contingency sediment characterization and sampling with a sonic drill at the Oregon Slough Downstream, Shallow Draft Federal Navigation Channel. Prepared by SQT, 29 January 2021. 6 pp.

8 PSET. 2021. PSET - Oregon Slough Downstream FNC (SSAP Approval). Email issued by B. Lohrman (EPA) for PSET, 25 February 2021. 2 pp with Attachment.

Table 2. Project Details Waterbody/river mile (RM) Columbia River, 101.4 to 104.6 Total proposed dredging volume (cy) ~425,000 Max. proposed dredging depth (includes overdepth allowance) -22 feet CRD (20+2 ft overdredge) Dredging area (acres, approx.) ~55 Dredge dimensions ~200 ft. wide for 2.3 miles Dredging method Pipeline, clamshell or hopper dredge Dredged material transport Barge, hopper Proposed disposal location(s) Columbia River flowlane Proposed dredging date(s) August 1 through December 15 Dredged material mgmt. units (DMMUs) 11

Sampling and Analysis Description: The USACE sampling and analytical program for the OSD FNC is summarized in Table 3. Actual grab sample station locations are shown in the 2020 SQER Table 1A and Map 1 (SDM Figure 1). Based on the inability to collect deeper-dredge prism material, a SSAP was prepared, approved by PSET, and implemented by the USACE. The USACE’ significantly modified their sampling approach by using a sonic core sample to penetrate deeper through the dredge prism and into the post-dredge surface. The PSET agreed to the USACE’ approach of considering the grab samples to represent the top 4-feet of dredge prism material because of the likelihood of those materials being more recently deposited coarse Columbia River sand. Actual sonic core sample station locations are shown in the 2021 SQER Table 1C and Map 1 (SDM Figure 2). The conceptual DMMU layout is shown in Figure 2 of the PSET-approved SSAP (SDM Figure 3).

Deviations from the SAP: Deviations from the PSET-approved SAP are identified in the 2020 SQER sections 2.1.1, 2.2.2, and 2.2.3 and are noted in SQER Tables 1A (grab sample summary) and 1B (core sample summary).

1. Core sampling with a standard vibracore sample and core catcher was not possible due to the presence of unconsolidated, coarse sand and gravel in the upper 6 to 9 feet of the dredge prism. Coarse sediments resulted in core refusals above project depth (-24 ft CRD) or core recoveries of 0 to 16%. After many coring attempts across the project and coordinating with Ecology staff from the field, the USACE switched to a standard Ponar grab sampler to characterize the surface layer DMMUs (OSD-01, OSD-02, OSD-03, OSD-06, OSD-09 and OSD-11) of the project.

2. Due to the coarse character of the surface sediments, the reference site for the contingency bioassays was relocated from Elk Rock Island in the Willamette River (~RM

16) to sandy sediments along Sauvie Island in the Columbia River (~RM 100).

Deviations from the SSAP: Deviations from the PSET-approved SSAP are listed in the 2021 SQER Table 1C for stations OSD-06D, OSD-06E, OSD-09D, and OSD-09E. The deviations included the inability to collect surface material from DMMUs 6 and 9 because the mudline elevation encountered in the field during sampling was deeper than what was encountered in 2020. This deviation did not result in a lack of data collection because the 2020 sampling collected sediment from the shallower depths.

Table 3. Sampling and Analysis Description Sample collection method Standard Ponar (†) or Sonic Drill (‡)

DP sample IDs / DMMU IDs (DP interval in ft CRD)

OSD-01†

(mudline to -22 ft)

OSD-02†

(mudline to -22 ft)

OSD-03†

(mudline to -14 ft)

OSD-06†

(mudline to -14 ft) OSD-09†

(mudline to -18 ft) OSD-11† (mudline to -22 ft)

OSD-04r‡ (-14 to -18 ft)

OSD-07r‡ (-14 to -18 ft)

OSD-05r‡ (-18 to -22 ft)

OSD-08r‡ (-18 to -22 ft)

OSD-10r‡ (-18 to -22 ft)

PDS sample IDs (-22 to -24 ft CRD) OSD-01Z‡ OSD-02Z‡ OSD-03Z‡ OSD-06Z‡ OSD-09Z‡ OSD-11Z‡

DMMU volume (CY) ~45,000 ~45,000 ~35,000 to ~40,000 ~35,000 to ~40,000 ~40,000 ~25,000

D re dg e

Pr is m Mudline range (ft CRD) -15.5 to -17.3† -14.5 to -18.3† -11.0 to -12.5† -7.8 to -9.8† -10.9 to -14.4† -19.1 to -21.4†

Composite (Y/N) Y Y Y Y Y Y Subsample /DMMU 3 3 3 / 2r 3 / 2r 3 / 2r 3 Subsample Archive (Y/N) Y Y Y Y Y Y

PD

S

L ay er

Depth range (ft CRD) -22 to -24‡ -22 to -24‡ -22 to -24‡ -22 to -24‡ -22 to -24‡ -22 to -24‡ Composite (Y/N) Y Y Y Y Y Y Subsample /PDS-layer 2r 2r 2r 2r 2r 2r Subsample Archive (Y/N) Y Y Y Y Y Y

Sediment Physical and Chemical Analysis (No. DP samples / No. PDS samples analyzed) Grain size 1/1 1/1 3/1 3/1 2/1 1/1 Total organic carbon 1/1 1/1 3/1 3/1 2/1 1/1 Total solids 1/1 1/1 3/1 3/1 2/1 1/1 Ammonia 1/1 1/1 3/1 3/1 2/1 1/1 Total sulfides 1/1^ 1/1^ 3/1^ 3/1^ 2/1^ 1/1^ Metals, freshwater 1/1 1/1 3/1 3/1 2/1 1/1 PAHs 1/1 1/1 3/1 3/1 2/1 1/1 SVOCs (phthalates, phenols, misc. extractables) 1/1 1/1 3/1 3/1 2/1 1/1 Pesticides 1/1 1/1 3/1 3/1 2/1 1/1 PCBs (Total Aroclors) 1/1 1/1 3/1 3/1 2/1 1/1 Butyltins 1/1 1/1 3/1 3/1 2/1 1/1 TPH (diesel [dx] and residual [rx] range) 1/1 1/1 3/1 3/1 2/1 1/1 Dioxin/Furans 1/1 1/1 3/1 3/1 2/1 1/1

Contingency Biological Analysis – dredge prism only, three DMMUs maximum Freshwater Bioassays 1* 1* 3* 3* 2* 1*

† = Ponar grab samples; ‡ = sonic drill core samples; ^ = sulfides analysis removed by USACE since no biological test are needed on the PDS; * = contingency bioassays not required based on sediment chemistry.

Total sulfides were removed from analysis by the USACE on the six Z-layer composite samples because biological tests are not necessary on the post-dredge surface and the overlying DMMUs were analyzed for sulfides. Only one of the 11 overlying DMMUs detected elevated sulfides (39.1 mg/kg, DMMU OSD-5r) above the SEF freshwater SL (39 mg/kg).

Results and Discussion: Analytical results for the USACE sampling event are summarized in Tables 5a (dredge prism) and 5b (post-dredge surface). The chemical analytical results from both SQERs were compared to the 2018 SEF freshwater SLs and to ODEQ’s freshwater fish-based SLV (22 ug/kg) to evaluate PCBs (total aroclors) and SLV (5.6 ng/kg) for dioxins and furans.

Total sulfides in DMMU OSD-05r (39.1 mg/kg) was the only DMMU or post-dredge surface sample with an analyte detected above an SEF SL (39 mg/kg). All other analytes were detected below SEF freshwater SLs or were non-detections (U) with method reporting limits (MRLs) below SLs. Sulfides are generally used to inform bioassay testing for potential non-treatment effects. When total sulfides are the sole parameter detected above an SEF SL, the PSET may determine sediments are suitable for unconfined, aquatic disposal and exposure.

Except for DMMU OSD-05r, all dredge prism samples (Table 5a) consisted of at least 91% sand with a total organic carbon (TOC) of 0.1% or less. DMMU OSD-05r was 67% sand, 26% silt, and 6% clay with a TOC of 0.3%.

Except for samples OSD-03Z and OSD-09Z, all post-dredge surface samples (Table 5b) consisted of at least 80% sand with a TOC of less than 0.19%. OSD-03Z consisted of 38% sand, 51% silt, and 11% clay with a TOC of 0.89%. OSD-09Z consisted of 3% gravel, 72% sand, 22% silt, and 3% clay with a TOC of 0.9%. DMMU OSD-05r is directly on top of OSD-3Z layer.

There were no exceedances of ODEQ’s bioaccumulative SLV for PCBs because all samples were non-detections (U) with an MRL (4.0 ug/kg) below the SLV (22 ug/kg). There were no exceedances of ODEQ’s bioaccumulative SLV for dioxins and furans because all samples had 2,3,7,8 TCDD TEQ results below the SLV (5.6 ng/kg).

No other parameters had detections, estimated concentrations (J) or non-detections (U) with elevated MRLs above an SEF freshwater SLs or an ODEQ SLVs.

Site Ranking: The sampling design was based upon a “moderate” rank due to the lack of dredging and agency concerns about CoCs at depth. Based on the dredge prism and post-dredge surface results and similar physical characteristics to surrounding projects, the PSET has assigned a “low” rank to the OSD shallow-draft sediments.

PSET Suitability Determination:

Dredge Prism – Chemical concentrations in OSD dredge prisms are below the SEF freshwater SLs and ODEQ SLVs as discussed above. As such, the OSD shallow draft FNC dredged prism material is suitable for unconfined, aquatic disposal per the 2018 SEF guidance without additional testing.

Post-Dredge Surface – Chemical concentrations in OSD post-dredge surface samples are below the SEF freshwater SLs and ODEQ SLVs as discussed above. As such, the OSD shallow draft FNC post-dredge surfaces are suitable for unconfined, aquatic exposure per the 2018 SEF guidance without additional testing.

Contact: This memorandum was prepared by Bridgette Lohrman (PSET co-lead) and James Holm (PSET Lead, USACE) and reviewed by the participating PSET agencies, identified above.

Questions regarding this memorandum should be directed to Bridgette Lohrman at (503) 326- 4006 or e-mail to: lohrman.bridgette@epa.gov.

mailto:lohrman.bridgette@epa.gov

Table 5a. Project Sediment Analytical Summary – Dredge Prism (sampled September 2020 and May 2021) Sediment Physical and Chemical Results

Sample Location (sample year) Surface (2020) Subsurface (2021) SEF SL1, freshwater (SLV†) DMMU ID / Sample ID:

Parameter

OSD-01, OSD-02, OSD-03,

OSD-06, OSD-09, OSD-11 OSD-04r OSD-05r OSD-07r OSD-08r OSD-10r

Grain size: gravel, sand, silt, clay (%)

Range: 2.8 to 8.2, 91.4 to 94.2,

0.6 to 4.5, 0.3 to 0.4 1.0, 95.7, 3.5, 0.3 0.5, 67.0, 26.3, 6.2 3.1, 95.1, 1.7, 0.1 1.5, 95.3, 3.0, 0.2 6.6, 92.7, 0.8, 0.1 --

Total Solids (%) Range: 76.1 to 88.2 79.0 74.55 80.62 84.30 79.78 -- Total Organic Carbon (%) Range: 0.04 to 0.1 0.05 0.30 0.06 0.05 0.05 -- Ammonia (mg/kg) Range: 0.45 U to 0.52 U 22.0 52.5 8.58 7.01 3.19 230

Total Sulfides (mg/kg) Range: 1.13 U to 1.26 U Range: 1.16 U to

1.26 U

Range: 1.21 U to 39.1

Range: 1.21 U to

1.24 U

Range: 1.23 U to

1.25 U

Range: 1.17 U to

1.20 U 39

Metals (mg/kg) Non-detect, Detect <SLs U, J Non-detect, Detect <SLs U, J Detect <SLs J Non-detect, Detect

<SLs U, J Detect <SLs J Non-detect, Detect <SLs U, J Varies

Total PAHs (ug/kg) Range: 4.8 J to 39.8 U

Non-detect, Detect <SL 39.9 U 62.7 39.9 U 40.0 U 40.0 U 17,000

SVOCs (ug/kg) (phenols, phthalates, misc.

extractables)

Non-detect, Detect <SLs U, J Non-detect, Detect <SLs U, J

Non-detect, Detect <SLs U, J

Non-detect, Detect <SLs U, J

Non-detect, Detect <SLs U, J

Non-detect, Detect <SLs U, J Varies

Pesticides (ug/kg) Non-detect <SLs U Non-detect <SLs U Non-detect <SLs U Non-detect <SLs U Non-detect <SLs U Non-detect <SLs U Varies

4,4’-DDD

1.0 U 1.0 U 1.0 U 1.0 U 1.0 U 1.0 U

4,4’-DDE 21

4,4’-DDT 100

PCBs, Total Aroclors (ug/kg) 4.0 U 4.0 U 4.0 U 4.0 U 4.0 U 4.0 U 110 (22†)

Butyltins (ug/kg)

3.69 U to 5.73 U

Non-detect <SLs U

3.84 U to 5.74 U

Non-detect <SLs U

3.83 U to 5.74 U

Non-detect <SLs U

3.83 U to 5.73 U

Non-detect <SLs U

3.86 U to 5.78 U

Non-detect <SLs U

3.86 U to 5.78 U

Non-detect <SLs U Varies

TPH (dx/rx) (ug/kg) Range: 5.55 U to 6.9 / 11.1 U to 37.8 6.05 U / 12.1 U 6.47 U / 17.3 6.10 U / 12.2 U 5.94 U / 11.9 U 6.08 U / 12.2 U 340 / 3,600 Dioxins/Furans, 2,3,7,8 TCDD TEQ (ng/kg)

ND=0 / ND = ½ EDL

Range: 0.0056 to 0.0268 /

0.0666 to 0.1030 0.0183 / 0.1620 0.0118 / 0.1470 0.0593 / 0.1840 0.0240 / 0.1920 0.0154 / 0.1620 (5.6†)

BOLD = Detection exceeds SEF freshwater screening level; U = Non-detection (ND) at the method reporting limit (MRL) or method detection limit (MDL), MRL reported (MDL in parenthesis); J = Estimated value between MDL and MRL; † = ODEQ (2007) freshwater fish-based bioaccumulation screening level value.

Table 5b. Project Sediment Analytical Summary – Post-Dredge Surface (sampled May 2021) Sediment Physical and Chemical Results

PDS Sample ID:

Parameter OSD-01Z OSD-02Z OSD-03Z OSD-06Z OSD-09Z OSD-11Z SEF SL1, freshwater

(SLV†)

Grain size: gravel, sand, silt, clay (%) 0.4, 95.6, 4.0, 0.1 0.5, 92.5, 7.0, 0.1 0.3, 38.1, 50.8, 10.6 1.0, 86.6, 11.0, 1.5 3.2, 71.9, 21.8, 3.1 2.4, 80.0, 16.1, 1.5 --

Total Solids (%) 76.1 75.4 68.7 82.0 74.5 74.7 -- Total Organic Carbon (%) 0.06 0.06 0.89 0.08 0.90 0.19 -- Ammonia (mg/kg) 28.4 20.6 169 31.5 29.5 18.6 230 Total Sulfides (mg/kg) -- -- -- -- -- -- 39

Metals (mg/kg) Non-detect, Detect <SLs U, J

Non-detect, Detect <SLs U, J Detect <SLs J Detect <SLs J Detect <SLs J Detect <SLs J Varies

Total PAHs (ug/kg) 40.0 U 39.9 U 39.9 U 20.4 66.6 J 39.8 U 17,000 SVOCs (ug/kg) (phenols, phthalates, misc.

extractables)

Non-detect, Detect <SLs U, J

Non-detect, Detect <SLs U, J

Non-detect, Detect <SLs U, J

Non-detect, Detect <SLs U, J

Non-detect, Detect <SLs U, J

Non-detect, Detect <SLs U, J Varies

Pesticides (ug/kg) Non-detect <SLs U Non-detect <SLs U Non-detect <SLs U Non-detect <SLs U Non-detect <SLs U Non-detect <SLs U Varies

4,4’-DDD

1.0 U 1.0 U 1.0 U 1.0 U

1.15 J

1.0 U

4,4’-DDE 0.36 J 21

4,4’-DDT 1.0 U 100

PCBs, Total Aroclors (ug/kg) 4.0 U 4.0 U 4.0 U 4.0 U 4.0 U 4.0 U 110 (22†)

Butyltins (ug/kg) Non-detect <SLs U Non-detect <SLs U Non-detect <SLs U Non-detect, Detect <SLs U

Non-detect, Detect <SLs U Non-detect <SLs U Varies

TPH (dx/rx) (ug/kg) 6.71 U / 13.4 U 6.68 U / 13.4 U 11.9 / 40.5 6.09 U / 12.2 U 6.92 U / 20.8 6.82 U / 13.6 U 340 / 3,600 Dioxins/Furans, 2,3,7,8 TCDD TEQ (ng/kg)

ND=0 / ND = ½ EDL

0.0304 / 0.1790 0.0124 / 0.1240 0.0289 / 0.1510 0.0304 / 0.1980 2.68 / 2.78 0.0216 / 0.1850 (5.6†)

BOLD = Detection exceeds SEF freshwater screening level; U = Non-detection (ND) at the method reporting limit (MRL) or method detection limit (MDL), MRL reported (MDL in parenthesis); J = Estimated value between MDL and MRL; † = ODEQ (2007) freshwater fish-based bioaccumulation screening level value.

Figure 1. Oregon Slough Downstream shallow draft Federal Navigation Channel, actual grab sample locations (sampled 11-13 September 2020).

Figure 2. Oregon Slough Downstream shallow draft Federal Navigation Channel, actual sonic drill sample locations (sampled 10-12 May 2021).

Figure 3. Oregon Slough Downstream shallow draft conceptual DMMU and Z-layer diagram (USACE SSAP, 2021).