1788443_Appendix C_Summary_DredgeSamplingData.pdf

Appendix C:

Sediment Sampling Data jsgeorgo@jsgdc.com Draft jsgeorgo@jsgdc.com Typewritten text Naval Station Norfolk FY 25 Maintenance Dredging and FY 26 Hydroid Net Maintenance james.georgo Typewritten Text eProject No. 1788443

FINAL

MARINE PROTECTION, RESEARCH, AND SANCTUARIES ACT (MPRSA)

SECTION 103 EVALUATION

NAVAL STATION NORFOLK (NSN) MAINTENANCE DREDGING

PHASE 1

NORFOLK, VIRGINIA

October 2023

Prepared for:

U.S. Environmental Protection Agency, Region 3 Four Penn Center 1600 John F. Kennedy Blvd.

Philadelphia, Pennsylvania 19103

Prepared by:

EA Engineering, Science, and Technology, Inc., PBC 225 Schilling Circle, Suite 400 Hunt Valley, Maryland 21031

Submitted by:

Department of the Navy Naval Facilities Engineering Systems Command (NAVFAC) Mid-Atlantic Division (MIDLANT) Norfolk, Virginia 23511

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Customer Service Hotline: 1-800-438-2474

UNITED STATES ENVIRONMENTAL PROTECTION AGENCY

REGION III

Four Penn Center 1600 John F Kennedy Blvd

Philadelphia, Pennsylvania 19103-2852

September 28, 2023

Mr. Andrew Beaudet, Acting Chief Regulatory Branch Norfolk District, U.S. Army Corps of Engineers 803 Front Street Norfolk, VA 23510-1096 Dear Mr. Beaudet:

Thank you for your August 14, 2023 request for concurrence on the suitability for ocean disposal of dredged material from the Norfolk Naval Station (NSN) Maintenance Dredging Phase I Project pursuant to Section 103 of the Marine Protection Research and Sanctuaries Act (MPRSA). Section 103 of the MPRSA specifies that all proposed operations involving transportation and dumping of dredged material into ocean waters be evaluated for potential environmental impacts. The Secretary of the Army has responsibility for this evaluation using criteria developed by the Administrator of the U.S. Environmental Protection Agency (EPA).

EPA Region 3 has completed its review of the draft Marine Protection, Research, and Sanctuaries Act (MPRSA) Section 103 Evaluation, dated June 2023, and contingent upon the conditions included in this letter, concurs that the proposed dredged material meets the Ocean Disposal Criteria (40 CFR 227).

Project Overview

The Naval Facilities Engineering Systems Command (NAVFAC) is evaluating maintenance dredging along the entire waterfront pier area at NSN, including the new Pier 11S berth extension area, CEP1111 bulkhead area, small boat channel, LAG marina, and V-50 basin.

The NSN facility is located in the Hampton Roads area of the southeastern portion of the Commonwealth of Virginia; it occupies 4 miles of waterfront, 11 miles of pier and wharf space on the Sewell’s Point peninsula. The project has been divided into two Phases, with Phase I representing the high-priority dredging areas. Approximately 2.3 million cubic yards (mcy) of maintenance material is anticipated to be removed from the high priority Phase I NSN pier and pier approach areas in late 2023 and 2024. Dredged material is proposed to be placed at the Norfolk Ocean Disposal Site (NODS).

EPA Region 3 conducted an independent determination of compliance with the Ocean

Disposal Criteria based on the following:

Exclusionary Criteria

In accordance with 40 CFR § 227.13(b), dredge material that meets the criteria set forth in the following paragraphs (b)(1), (2), or (3) of this section is environmentally acceptable for ocean dumping without further testing under this section:

1. Dredged material is composed predominantly of sand, gravel, rock, or any other naturally occurring bottom material with particle sizes larger than silt, and the material is found in areas of high current or wave energy such as streams with large bed loads or coastal areas with shifting bars and channels; or

2. Dredged material is for beach nourishment or restoration and is composed predominantly of sand, gravel or shell with particle sizes compatible with material on the receiving beaches; or

3. When the material proposed for dumping is substantially the same as the substrate at the proposed disposal site; and the site from which the material would be dredged is far removed from known existing and historical sources of pollution to provide reasonable assurance that such material has not been contaminated by such pollution.

The material in the NSN Phase I project area does not meet the exclusionary criteria set forth under 40 CFR § 227.13(b).

Evaluation of Bulk Sediment and Water Quality Criteria (WQC)

Sediments from NSN Phase I consisted primarily of fine-grained materials, consisting of 84.8% to 99% silt and clay. The physical characteristics of Phase I sediments were most similar to those in the subsurface sample from Willoughby Bank Reference Site, which was comprised of 77% silt and clay. For this project, surficial sediments from 66 discrete locations were collected to develop 15 dredging unit (DU) composite samples. Per sediment sampling, metals, PAHs, pesticides, SVOCs, and dioxin/furan congeners were detected above the laboratory reporting limit (RL). Arsenic, copper, nickel, and zinc exceeded the threshold effects level (TEL), but did not exceed probable effects level (PEL). The dioxin toxicity equivalency quotient (TEQs) ranged from 6.92 to 12.6 ng/kg in the composite DU samples. Four SVOCs (benzoic acid, dibenzofuran, di-n-butyl phthalate, and phenol) were also detected in the composite samples.

Standard elutriates (15), site water, and receiving water were analyzed and compared to the USEPA saltwater acute water quality criteria (WQC) for aquatic life. Ammonia exceeded the WQC by a factor ranging from 1.77 - 4.2. Cyanide exceeded WQC for aquatic life in 6 elutriates by a factor ranging from 8.1 – 9.7; however, the laboratory reporting limit (RL) for cyanide exceeded by a factor of 10. Although cyanide was estimated detected below the laboratory RL in each of the standard elutriates, cyanide is the most restrictive constituent and was conservatively used to determine WQC limiting permissible concentration (LPC) compliance with the Tier II short-term fate (STFATE) model for elutriates.

Concentrations of cyanide require a dilution of 9 to comply with the acute cyanide criteria and meet the WQC LPC for placement of dredged material inside the boundary of NODS. Results of the STFATE model indicated a dilution ranging from 119-fold to 133-fold would occur within the boundaries of the site within 4 hours following placement of dredged material, and the elutriate plume would travel a maximum distance of 4,384 ft from the location of discharge during the 4-hour mixing period.

Based on the above information, the standard elutriates from NSN Phase I are in compliance with 40 CFR § 227.6(c)(1) and 227.27(a)(1).

Acute Water Column Toxicity

Acute water column bioassays were conducted using the following three species: Mytilus

sp. (blue mussel), Americamysis bahia (opossum shrimp), and Menidia beryllina (inland silverside) to evaluate development and survival of test organisms when exposed to project sediments and elutriate preparation water (site water). The Mytilus sp. tests measured developmental effects to embryos, and the A. bahia and M. beryllina tests measured effects to organism survival. The untreated Mytilus sp., the 48-hr EC50 ranged from 21.5 to >100%, and normal embryo development in the 100 percent untreated elutriates ranged from 0 to 51%. Each sample was at least 10 percent less than, or statistically different from, the laboratory control of 74 to 85% normal development. Site water had 83% normal embryo development. Using ammonia-purged sediment, the 48-hr EC50 was >100% elutriate. In the 100% elutriates, normal development ranged from 46-84%. Normal development for 4S-4SA, 6N-6NA, and 10N-10NA were at least 10 percent less than and statistically different from the laboratory control (ranging from 77 to 87%).

A. bahia and M. beryllina both had a 96-hr LC50 of >100% elutriate for each sample, and survival ranged from 90 to 100% and 84 to 96%, respectively. For both species, survival was not significantly different from the laboratory control, indicating that the elutriates were not acutely toxic.

STFATE modeling was conducted to determine if the results of the water column bioassays would meet the water column toxicity LPC for ocean placement. The LPC for the water column toxicity is the concentration that does not exceed 0.01 of the EC50/LC50 value within a 4-hour dilution period inside the boundary of the ocean placement site. If ammonia is a demonstrated toxicant, the LPC for water column toxicity is the concentration that does not exceed 0.05 of the EC50/LC50 value within a 4-hour dilution period inside the boundary of the ocean placement site. Since ammonia was the main constituent in the NSN Phase I elutriates contributing to water column toxicity based on the comparison of untreated and ammonia-purged elutriate results, a dilution of 19- to 90-fold is required to meet the LPC for these samples.

Results of the STFATE modeling for placement at NODS indicated that the required dilutions would be achieved at a distance of 4,384 ft from the point of discharge. During the 4-hour mixing period, dilutions ranging from 119- to 133-fold would be achieved, and the elutriate would travel a maximum distance of 4,384 ft from the point of discharge.

Based on the results of the water column bioassays and STFATE modeling, the NSN Phase I elutriates meet the LPC for water column toxicity for placement at NODS for a maximum discrete discharge volume of 20,000 cy; the material complies with 40 CFR § 227.6(c)(2) and 227.27(b).

Whole Sediment Bioassay Evaluation

For 10-day whole sediment bioassay, Ampelisca abdita (marine amphipod) and

Leptocheirus plumulosus (estuarine amphipod) were exposed to the NSN Phase I sediment and overlying water to determine survival outcomes as statistically compared to survival in the Willoughby Bank Reference Site subsurface sediment.

A. abdita and L. plumulosus survival in TSC-W sediments ranged from 88-96% and 92- 98%, respectively. None of the survival results were significantly different from the reference site survival for both A. abdita and L. plumulosus. Exposure to NSN Phase I sediments did not exceed the allowable percent difference (20%) of mortality from the reference sediment;

therefore, NSN Phase I sediments meet the LPC for benthic toxicity for placement at NODS.

Bioaccumulation Evaluation

To evaluate chronic exposure to NSN Phase I sediments, a 28-day benthic bioaccumulation exposure study with Nereis virens (sand worm) and Tapes japonica (manila clam) was performed to determine survival and the potential uptake of contaminants in organism tissue. Per the bulk sediment chemistry results, tissue samples were analyzed for metals, dioxin/furan congeners, PAHs, pesticides (DDT series only), select SVOCs (benzoic acid, dibenzofuran, di-n-butyl phthalate, and phenol only), lipids, and percent moisture and were statistically compared to the reference site.

The results of the bioaccumulation study demonstrated that none of the upper confidence level of the mean (UCLM) values for the tested analytes exceeded the U.S. Food and Drug Association Action/Guidance/Tolerance Values for metals or 4,4’-DDT. There are no available USFDA Action/Guidance/Tolerance Levels for dioxin and furan congeners, PAHs, or SVOCs.

For DUs 2S-2SA, 4N-4NA, 4S-4SA, mean concentrations of arsenic in clam tissue statistically exceeded the mean reference (WBREF-SUB) tissue concentration but did not statistically exceed the mean pre-test tissue concentration or the USEPA South Atlantic Bight background arsenic concentrations for bivalves. Additionally, the UCLMs were below the Ecological Non-Specific Effects Threshold for bivalves. None of the mean concentrations for metals in worm tissue or PAHs, dioxins/furans, select SVOCs, or select pesticides in clam and worm tissue statistically exceeded the mean reference or pre-test tissue concentrations. These results indicate that the mean concentrations of detected analytes in the NSN Phase I tissue samples are not ecologically significant and, therefore, meet the LPC for ocean placement at NODS.

Based on the assessment of chemical analyses performed on pre-test tissues and tissues exposed to sediment from the NSN Phase I and Willoughby Bank subsurface reference sediments, it is anticipated that ocean placement of the dredged material from NSN Phase I at NODS will not result in ecologically significant bioaccumulation of contaminants. Therefore, the dredged material meets the LPC for bioaccumulation, and complies with the benthic criteria of 40 CFR Part 227.13 (c) (3).

Conclusion

In conclusion, NSN Phase I sediments meet the criteria for the LPC for WQC, water column toxicity, benthic toxicity, and benthic bioaccumulation. Based on the results of the STFATE modeling, placement events up to 20,000 cy comply with the LPC.

In accordance with the Water Resources Development Act of 1992 amendments to MPRSA, disposal activities must be conducted in accordance with the NODS Site Management and Monitoring Plan (SMMP) including the following:

• Disposal will occur within boundaries of the site and at least 100 meters from the perimeter of the disposal site;

• Material placed at the disposal site from NSN Phase I shall not exceed 20,000 cy of material at any given time;

• The disposal site shall be surveyed before and after the project to ensure proper placement of materials and compliance with NODS site conditions;

• Each disposal vessel will have an Electronic Tracking System, and the NAVFAC will maintain all data associated with the project; and

• NAVFAC will provide EPA with a disposal summary report following completion of the project.

This concurrence is conditioned upon implementation of the above requirements and is valid for a term of three years from September 28, 2023. Use of NODS after September 28, 2026, will require further evaluation of the proposed dredged material. Should you have any questions regarding this concurrence or use of NODS, please contact me or Stephanie Jacobs at 215-814-2762.

Sincerely, Catherine Magliocchetti, Acting Chief Wetlands Branch, Water Division U.S. EPA Region 3

MARINE PROTECTION, RESEARCH, AND SANCTUARIES ACT (MPRSA)

SECTION 103 EVALUATION

NAVAL STATION NORFOLK (NSN) MAINTENANCE DREDGING

PHASE 1

NORFOLK, VIRGINIA

October 2023

1. DREDGING AND PLACEMENT PROJECT INFORMATION.

The subject of this evaluation is the maintenance dredged material from the Naval Station Norfolk (NSN), and the subsequent placement of dredged material in the Norfolk Ocean Disposal Site (NODS) (Figures 1 and 2). Maintenance dredging activities for NSN waterfront facilities (piers, slips, turning basins, access channels, bulkheads, and marinas) are currently authorized under a regional permit (RP) – 18-RP-02 (NAO-2010-0089 / VMRC Number 18-V1285). This permit authorizes upland placement of the maintenance material at the Craney Island Dredged Material Management Area (CIDMMA) and expires on 5 September 2023. However, current capacity limitations at the CIDMMA preclude placement of material from non-U.S. Army Corps of Engineers (USACE) projects at the CIDMMA until at least 2025. The Naval Facilities Engineering Systems Command (NAVFAC) has performed a comprehensive dredged material evaluation for the entire waterfront pier area at NSN including the new Pier 11S berth expansion area, CEP111 bulkhead area, small boat channel, LAG marina, and V-50 basin to support future maintenance dredging and the acquisition of a new 10-year permit that will include multiple dredged material placement options (CIDMMA, upland, and ocean placement).

Due to the overall number of piers and waterfront areas requiring maintenance dredging, the volume of dredged material, and the number of defined dredging units (DUs), the NSN sampling and testing program was conducted in two phases – Phase 1 and Phase 2 (Figure 3). Phase 1 included areas with highest priority dredging in calendar years 2023 and 2024, and Phase 2 included areas proposed for dredging in 2025 and subsequent years. This Section 103 evaluation is specific to the Phase 1 high-priority dredging areas. The Phase 2 dredging areas will be evaluated in a separate Section 103 document.

The NODS was identified as the location for the placement of the maintenance material from the NSN Phase 1 project area because: (1) the NODS is designated to provide capacity for long-term management of dredged material from the lower Chesapeake Bay region and suitable materials from Norfolk Harbor, and (2) it has the capacity to accept the material.

a. Dredging Location. NSN is located in the Hampton Roads area of the southeastern portion of the Commonwealth of Virginia. The facility occupies approximately 4 miles of waterfront and approximately 11 miles of pier and wharf space on the Sewell’s Point peninsula (Figure 1). The entire project area has been divided into 34 DUs, 15 of which were evaluated during the Phase 1 sampling/testing program (Figure 3). Dredging areas for the Phase 1 sediment characterization had variable maintenance depths of -39 feet (ft), -43 ft, -48 ft, or -53 ft MLLW (Figure 4).

Figure 1. Dredging Areas and Site Location Map, Naval Station Norfolk, Norfolk, Virginia

Figure 2. Location Map: Willoughby Bank Reference Site, Chesapeake Bay Control Site, and Norfolk Ocean Disposal Site.

Figure 3A. Phase 1 Dredging Units – Piers 10, 11, 12, and 14, Naval Station Norfolk, Norfolk, Virginia.

Figure 3B. Phase 1 Dredging Units – Piers 1, 2, 4, 6, and 7, Naval Station Norfolk, Norfolk, Virginia.

Figure 4. Maximum Dreading Depth (ft MLLW) in Each Dredging Area, Naval Station Norfolk, Norfolk, Virginia.

b. Core Borings. No core borings from the NSN Phase 1 project area were collected for submittal with this Section 103 Evaluation.

c. Volume of Material to be Dredged. It is anticipated that approximately 2.3 million cubic yards

(cy) of maintenance material in the high priority Phase 1 NSN pier and pier approach areas will be removed in the dredging to be performed in the late 2023 and 2024 timeframe.

Dredging Unit

Project Dredging Depth

(ft MLLW)

Maximum Sediment

Volume (cy)(a)

1N/1NA -48 75,000

2S/2SA -43 100,000

2N/2NA -43 100,000

4S/4SA -39 90,000

4N/4NA -39 35,000

6S/6SA -48 100,000

6N/6NA -48 185,000(b)

7S/7SA -43 45,000

10N/10NA -48 130,000(b) 11S/11SA -53 265,000(b) 11N/11NA -53 170,000(b) 12S/12SA -53 220,000(b) 12N/12NA -53 285,000(b) 14S/14SA -53 275,000(b) 14N/14NA -53 240,000(b)

Notes:

(a) Based on June/July 2022 bathymetric surveys; volume based on dredging projected from 2023 through 2026.

(b) More than one dredging cycle/event planned during the 2023 to

2026 time period; maximum volume from a single dredging event does not exceed 150,000 cy.

d. Grain Size of Dredged Material. Sediments collected in November 2023 from the Phase 1 DUs were comprised primarily of fine-grained materials and consisted of 84.8 to 99.0 percent silt+clay (Table 1 and Figure 5). The physical characteristics of sediments from the Phase 1 DUs were most similar to the physical characteristics of sediments in the subsurface sample from Willoughby Bank Reference Site (WBREF-SUB) which was comprised of 77.0 percent silt+clay.

e. Bathymetric Information. The most recent bathymetric surveys of the NSN maintenance dredging project area were conducted in June/July 2022. The bathymetry data for the areas to be dredged are included in Attachment I.

Figure 5. Grain Size Distribution in the Ocean Placement Composite Samples (NSN Phase 1) and Willoughby Bank Reference Site (2022).

Source: EA Engineering, Science, and Technology, Inc., PBC (EA) 2023

GRAVEL SAND SILT CLAY

f. Description of the Disposal Area. The NODS (Figure 2) is located in the Atlantic Ocean approximately 17 statute miles east of Cape Henry Channel and is approximately 50 square nautical miles in size (40 Code of Federal Regulations [CFR] Part 228). The site is circular with a radius of 4 nautical miles and a water depth that ranges from 43 to 85 ft (USACE Norfolk District and Virginia Port Authority 2018). The Chesapeake Light Tower is located approximately 2 statute miles south/southeast of the site.

The center point coordinate of the NODS is (40 CFR Part 228):

Latitude: 36º 59’ 00” N Longitude: 75º 39’ 00” W

The NODS has unlimited capacity and is designated for use as an alternate site for the lower Chesapeake Bay channels as well as a placement location for suitable materials from the Norfolk Harbor Channels within the Port of Hampton Roads (CENAO 1994 cited by USACE Baltimore District 2005). The Final Environmental Impact Statement for the designation of the Norfolk Ocean Disposal Site (U.S. Environmental Protection Agency [USEPA] Region 3 1992) states that the site was intended to provide capacity for long-term management of dredged material from the Lower Chesapeake Bay and suitable material from Norfolk Harbor. However, the Final Environmental Impact Statement also states that the site could be used for placement of material from other dredging projects that meet the requirements of Section 103 of the MPRSA. The designation of the site in 40 CFR Part 228.15 indicates the “site shall be limited to suitable dredged material which passed the criteria for ocean dumping.”

Prior to 2008, the only use of the NODS was by the U.S. Navy in August 1993. Approximately 51,000 cy of dredged material from the Naval Supply Center Cheatham Annex and 475,000 cy of dredged material from the Naval Weapons Station Yorktown were placed at the site. Dredged material from both projects was primarily comprised of silts and clays. Since 2010, other projects that have been placed at the NODS, are currently being placed at the NODS, or are approved for future placement at the NODS include: The Virginia Department of Transportation Midtown Tunnel (1,121,642 cy placed October 2013 to October 2014), Joint Base Langley Eustis (JBLE) Skiffes Creek Channel (128,244 cy placed November 2014 to December 2014), JBLE-Fuel Pier Basin (57,122 cy placed February 2019 to July 2019), JBLE-Back River Channel (125,723 cy placed February 2019 to July 2019), Cheatham Annex (88,000 cy placed in 2022), and Naval Weapons Station Yorktown R3 Pier (110,000 cy placed in 2022). The maintenance material for Norfolk Inner Harbor (1 mcy) is currently being dredged and placed at the NODS. Other projects that have been previously permitted or approved for use of the NODS include: the Craney Island Eastward Expansion Project, and the Chesapeake Bay Bridge Tunnel – Parallel Thimble Shoal Tunnel. The NODS serves as a backup placement option for segments of the Norfolk Harbor Channel Deepening, including: Norfolk Harbor Channels-Sewells Point to Lamberts Bend reach, Thimble Shoal Channel-East, Meeting Area 1, Meeting Area 2, and Atlantic Ocean Channel. The NODS also serves as a backup placement option for the maintenance materials from the Upper Chesapeake Bay approach channels to the Port of Baltimore that pass the ocean placement criteria.

A Site Monitoring and Management Plan (SMMP) for the NODS became effective in 1998, was renewed in February 2009, and was renewed again in February 2019. The goal of the SMMP is to protect the marine environment and document the dredged material placement activities at the NODS (USACE Norfolk District/USEPA Region 3 2019). The objective of the SMMP is to provide guidelines in making management decisions necessary to fulfill the mandated responsibilities to protect the marine environment. The specific management objectives of the NODS include: (1) protection of the marine environment, living resources, and human health and welfare; (2) documentation of disposal activities at the NODS and provision of information that is useful in managing the dredged material placement activities; and (3) beneficial use of dredged material whenever practical (USACE Norfolk District/USEPA Region 3 2019).

g. Expected Start, Duration, and End of Dredging. Maintenance dredging for the Phase 1 areas at NSN is expected to start in Fall 2023 and continue through 2024.

h. Location of Placement within the NODS. The dredged material will be mechanically excavated, transported to the NODS using bottom dump scows, and placed in a designated placement zone within the NODS where it will be evenly distributed. The proposed placement zone within the NODS for the NSN Phase 1 material was determined based on consultation with USEPA Region 3 and USACE Norfolk District (Figure 6). Progress surveys of portions of the active zone during placement periods will be utilized, if warranted, to ensure proper placement/distribution of materials.

Placement of dredged material from NSN Phase 1 areas was modeled using the USACE Short- Term Fate of Dredged Material Disposal in Open Water (STFATE) model, which simulates the movement of the disposed material as it falls through a water column, spreads over the bottom, and is transported as suspended sediment by the ambient current. Multiple discharge scenarios were modeled to determine the dilution achieved and distance the elutriate plume moved within the 4-hour allowable mixing period following discharge and to determine the maximum discrete discharge volume per placement event that would comply with the limiting permissible concentration (LPC) for water quality criteria (WQC) and water column toxicity.

i. Compliance with NODS Site Designation Conditions. USEPA and USACE manage the NODS through a joint SMMP. Use of the site for dredged material placement will comply with site requirements. The NAVFAC or its contractors will perform after-placement bathymetric surveys of the designated placement area within the NODS. These surveys may be performed periodically to ensure compliance with contract requirements and the SMMP (USACE Norfolk District/USEPA Region 3 2019) for the NODS. Other surveys may be performed as necessary.

Figure 6. Designated NSN Phase 1 DUs Dredged Material Placement Zone in the NODS.

2. EXCLUSIONARY CRITERIA

The exclusionary criteria (40 CFR Part 227.13) are used to determine if material is acceptable for ocean placement without further testing. If the material meets any of the following three criteria, it is considered environmentally acceptable for ocean placement without further Tier II (chemical) or Tier III (ecotoxicological) testing:

1. The dredged material is comprised predominately of sand, gravel, rock, or any other naturally occurring bottom material with particle sizes larger than silt, and the material is found in areas of high current or wave energy.

2. Dredged material is for beach nourishment or restoration and is comprised predominately of sand, gravel, or shell with particle sizes comparable with material on the receiving beaches.

3. The material proposed for placement is substantially the same as the substrate at the proposed placement site, and the site from which the material proposed for placement is to be taken is far removed from known sources of pollution so as to provide reasonable assurance that such material has not been contaminated by such pollution.

Based on the results of previous testing in 2011, 2015, and 2018 (Tetra Tech 2011, CH2M 2015, and CH2M 2018, respectively) and results of grain size analyses conducted in 2022/2023, the maintenance material from the NSN Phase 1 dredging areas does not meet the exclusionary criteria (40 CFR Part 227.13).

3. NEED FOR TESTING FOR OCEAN PLACEMENT

a. Requirement for Testing. The NSN Phase 1 maintenance sediments are comprised of silts and clays and do not meet the exclusionary criteria set forth under 40 CFR 227.13(b). Therefore, tiered testing in accordance with 40 CFR 227.32, and following protocols in the Ocean Testing Manual (USEPA/USACE 1991), the Mid-Atlantic Regional Implementation Manual (USEPA Region 3 2000), and the Southeast Regional Implementation Manual (USEPA/USACE 2008), was conducted to determine if the proposed dredged material from NSN Phase 1 meets the LPC for ocean placement at the NODS.

b. Dates of Previous Dredging. Ten of the fifteen Phase 1 DUs have been dredged since 2020 and each time the dredged material was placed at CIDMMA. In 2020, 10N/10NA, 11N/11NA, 12N/12NA, 12S/12SA, 14N/14NA, and 14S/14SA were dredged removing a combined 485,996 cy of material. In 2021, 1N/1NA, 6N/6NA, 6S/6SA, and 11S/11SA were dredged removing a combined 372,524 cy of material. Because CIDMMA has historically been used for placement of the NSN maintenance material, there is no previous ocean disposal concurrence for these sediments.

c. Results of Previous Testing. Maintenance material from NSN piers and pier approaches has not been previously tested for ocean placement but has been previously tested for upland placement in 2011, 2015, and 2018 (Tetra Tech 2011, CH2M 2015, and CH2M 2018, respectively). The 2011 sampling program (Tetra Tech 2011) included testing of surficial sediments at 55 locations and testing of physical properties, metals, polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), total petroleum hydrocarbons (TPH), and total organic carbon. Data from the 2011 sampling indicated that the materials were primarily fine-grained (>90% silt/clay at 50 of the 55 sampling locations), arsenic and several PAHs exceeded residential risk-based concentrations. The 2015 sampling and testing program (CH2M 2015) included a combination of grab or core sampling at 177 discrete locations and testing of 59 composite samples. The majority of samples were tested for TPH – diesel range organics (DRO) only to assess the CIDMMA criterion. The 2018 sampling and testing program (CH2M 2018) included sampling of 260 discrete locations (cores and surface grabs). The majority of samples were tested for TPH-DRO only to assess the CIDMMA criterion. MPRSA Section 103 Tier II and Tier III testing has not been previously conducted for the NSN Phase 1 project areas.

d. Locations for Previous Testing. Previous sampling events were not tested for ocean placement.

Information on previous sampling locations can be found in Tetra Tech 2011, CH2M 2015, and

CH2M 2018.

e. Recent Events Influencing Testing Results. There are no known events to have occurred in the project vicinity either immediately before or following the November 2022 sampling event that would be expected to influence the sediment chemistry or bioassay results presented for the maintenance sediments in this evaluation.

4. WATER COLUMN DETERMINATIONS

In November 2022, 66 discrete locations in the NSN project area were sampled. These locations were used to create 15 DU composites which were submitted for tiered testing following protocols in the Ocean Testing Manual (USEPA/USACE 1991), the Mid-Atlantic Regional Implementation Manual (USEPA Region 3 2000), and the Southeast Regional Implementation Manual (USEPA/USACE 2008). Results of the studies and a description of the sampling and testing methodologies are detailed in the Sampling and Analysis Plan (SAP) (EA 2022a) and in Evaluation of Dredged Material for Ocean and Upland Placement: Naval Station Norfolk Maintenance Dredging, Norfolk – Phase 1, Virginia (EA 2023).

Sediment cores from 66 locations were collected with a vibracore unit (Figure 7A and 7B). Fifteen composite samples were created, each consisting of sediment cores from three to six discrete locations within each DU. The 15 DU composites were submitted for physical and chemical analyses and used for standard elutriate preparation and ecotoxicological testing. Water targeted for chemical analysis and elutriate preparation was collected from one location in the vicinity of the NSN Phase 1 project area (Figure 7B). Receiving water was collected from the NODS.

Reference sediment (surface and subsurface) was collected from the Willoughby Bank Reference Site. Control sediment for amphipod bioassays was collected from the USEPA-designated control site in the lower Chesapeake Bay (Figure 2).

Figure 7A. Sampling Locations, Phase 1 Dredging Units - Piers 10, 11, 12, and 14, Naval Station Norfolk, Norfolk, Virginia.

Figure 7B. Sampling Locations, Phase 1 Dredging Units - Piers 1, 2, 4, 6, and 7, Naval Station Norfolk, Norfolk, Virginia

a. Sediment Testing. Target analytes for the 2022/2023 sediment testing were based on consultation with USACE Norfolk District and USEPA Region 3. Results of the physical and chemical testing of the bulk sediment from the NSN Phase 1 project area and comparisons to marine sediment quality guidelines (SQGs) (MacDonald et al. 1996; Canadian Council of Ministers of the Environment 2001) are summarized in Tables 1 through 9. Fifteen bulk sediment composites and two reference sediments were tested for the following target constituents:

Acid volatile sulfide (sediment only) Ammonia (NH3-N) Butyltins Chlorinated pesticides Cyanide Dioxins and furan congeners Metals Mercury Nitrate Nitrite Organophosphorus pesticides PCB congeners PAHs Semivolatile organic compounds (SVOCs) Simultaneously extracted metals (sediment only) Total Kjeldahl nitrogen Total sulfide Total organic carbon Total phosphorus

In addition, the following physical analyses were conducted for the bulk sediments:

Grain size determination Atterberg limits Total solids Bulk density Specific gravity

Detailed results of the bulk sediment testing are provided in Evaluation of Dredged Material for Ocean and Upland Placement: Naval Station Norfolk Maintenance Dredging – Phase 1, Norfolk, Virginia (EA 2023).

The results of the grain size analysis indicated that the NSN Phase 1 project area sediment composites were primarily comprised of fine-grained materials, ranging from 84.8 to 99.0 percent silt/clay (Table 1 and Figure 5). Results for metals and organic constituents are provided in Tables 2 to 9. Metals (Table 3), PAHs (Table 5), pesticides (Table 6), dioxin/furan congeners (Table 7), and SVOCs (Table 8) were the only analyte groups with constituents detected above the laboratory reporting limit (RL) in the sediments. PCB congeners, organophosphorus pesticides, and butyltins were not detected in the NSN Phase 1 project area sediments.

Comparisons of chemical concentrations in the NSN Phase 1 sediment to marine SQGs indicated four of the tested metals (arsenic, copper, nickel, and zinc) were detected at concentrations that exceeded their respective TEL values in the composite sediment samples; none of the detected metals exceeded PEL values. Each of the 18 tested individual PAHs were detected in the composite sediment samples. Twelve of the detected PAHs exceeded their respective TEL value and five of those individual PAHs (2-methylnaphthalene, acenaphthene, fluorene, naphthalene, and phenanthrene) also exceeded the PEL value for one DU (10N-10NA).

Three chlorinated pesticides (4,4’-DDE, 4,4’-DDT, and endrin) were detected in the composite sediment samples; 4,4-DDE and endrin concentrations were estimated below the laboratory RL, and 4,4’-DTT was measured at a low concentration above the laboratory RL. Dioxin and furan congeners were detected in each of the composite samples, a majority of which were measured at concentrations estimated below the laboratory RL. The dioxin TEQs (ND=RL) ranged from 6.92 and 12.6 ng/kg. Four SVOCs (benzoic acid, dibenzofuran, di-n-butyl phthalate, and phenol) were also detected in the composite samples.

b. Water Column Elutriate Testing. Fifteen standard elutriates were prepared for the NSN Phase 1 project area using the sediment composites and dredging site water. Receiving water was also collected within the boundaries of the NODS. Results of the elutriate, site water, and receiving water chemical analyses and comparisons to USEPA acute saltwater quality criteria for aquatic life (USEPA 2022) are summarized in Tables 10 to 17. Details of the elutriate analysis are provided in Evaluation of Dredged Material for Ocean and Upland Placement: Naval Station Norfolk Maintenance Dredging – Phase 1, Norfolk, Virginia (EA 2023).

Elutriate preparation water (dredging site water) chemistry results indicated that several chemical constituents were detected in the elutriate preparation water. The majority of detected concentrations were low or estimated below the laboratory RL. Ammonia exceeded the calculated USEPA acute saltwater WQC for aquatic life (9.59 milligrams per liter) in each of the NSN Phase 1 area elutriates by a factor ranging from 1.77 to 4.2. Cyanide exceeded the USEPA acute saltwater WQC for aquatic life (1 microgram per liter) in six of the elutriates by a factor ranging from 8.1 to 9.7. The laboratory RL for cyanide exceeded the USEPA acute saltwater WQC for aquatic life by a factor of 10, in the remaining NSN Phase 1 project area elutriates. Although cyanide was either not detected or was estimated detected below the laboratory RL in each of the standard elutriates, cyanide was conservatively used in the STFATE model as the constituent requiring the greatest dilution to achieve the WQC for the NSN Phase 1 elutriates.

To determine whether the sediments from the NSN Phase 1 areas meet the WQC LPC requirement, STFATE modeling was conducted. The LPC for WQC is the elutriate concentration which:

1) Does not exceed the WQC outside the site boundary during the first 4 hours, and

2) Does not exceed the WQC anywhere in the marine environment after 4 hours.

STFATE modeling was conducted to confirm that sufficient dilution would be achieved to meet the WQC LPC and to confirm that the elutriate plume would stay within the boundary of the NODS placement site within the 4-hour period required by the MPRSA. STFATE modeling was conducted using the specifications of the NODS (i.e., dimensions and water column properties), physical characteristics of the sediment collected from the NSN Phase 1 project area (i.e., grain size and specific gravity), and the concentrations of the chemical(s) in the elutriates that exceeded applicable WQC (Attachment II). The Tier II STFATE evaluations were conducted using an assumed background concentration of zero, mechanical dredging, and a 20,000-cy discrete discharge volume.

The model output (Table 18) indicated that cyanide required a dilution factor of 9 to meet the WQC LPC for placement at the NODS. Results of STFATE modeling indicated that a dilution of 9-fold would be achieved at a distance ranging from 1,273 to 1,414 ft from the location of discharge. The model predicted that a dilution ranging from 119- to 133-fold would be achieved during the allowable 4-hour mixing period, and the elutriate plume would travel a maximum distance of 4,384 ft from the location of discharge during the 4-hour mixing period.

Based on the results of the STFATE modeling, the standard elutriates from the NSN Phase 1 DUs meet the LPC for WQC for placement at the NODS.

c. Water Column Bioassays. Three water column species, Mytilus sp. (blue mussel), Americamysis bahia (opossum shrimp), and Menidia beryllina (inland silverside), were exposed to elutriates created from the NSN Phase 1 project area sediments and the elutriate preparation water (site water), and to a laboratory control. The blue mussel tests measured developmental effects to embryos, and the opossum shrimp and inland silverside tests measured effects to organism survival. The test protocols are detailed in the SAP (EA 2022a), EA Ecotoxicology Laboratory Quality Assurance and Standard Operating Procedures Manual (EA 2022b), and Evaluation of Dredged Material for Ocean and Upland Placement: Naval Station Norfolk Phase Maintenance Dredging – Phase 1, Norfolk, Virginia (EA 2023). Results for the water column bioassays are summarized in Table 19.

Mytilus sp.

The 48-hour median effective concentration (EC50) in the untreated elutriates ranged from 21.5 to >100 percent. Normal development in the 100 percent untreated elutriates ranged from 0 to 51 percent. Each sample was at least 10 percent less than the control and statistically different from the laboratory control. The laboratory controls for the untreated elutriates had normal embryo development ranging from 74 to 85 percent. The site water sample NSN22-WAT had 83 percent normal embryo development (Table 18). For each of the elutriates created using ammonia-purged sediment, the 48-hour EC50 value was greater than 100 percent elutriate. Normal development in the 100 percent elutriates ranged from 46 to 84 percent. Normal development for 4S-4SA, 6N- 6NA, and 10N-10NA were at least 10 percent less than and statistically different from the laboratory control. The laboratory controls had normal embryo development ranging from 77 to 87 percent (Table 19).

Americamysis bahia For each of the elutriates, the 96-hour median lethal concentration (LC50) value was greater than 100 percent elutriate. Survival in the 100 percent elutriates ranged from 90 to 100 percent and was not significantly different from the laboratory control, indicating that the elutriate was not acutely toxic to A. bahia. After 96 hours of exposure, the minimum survival in the laboratory controls ranged from 92 to 100 percent (Table 19).

Menidia beryllina For each of the elutriates, the 96-hour LC50 value was greater than 100 percent elutriate. Survival in the 100 percent elutriates ranged from 84 to 96 percent and were not significantly different from the laboratory control, indicating that the elutriate was not acutely toxic to M. beryllina. After 96 hours of exposure, the minimum survival in the laboratory controls ranged from 90 to 98 percent (Table 19).

STFATE Modeling and LPC Compliance STFATE modeling was conducted to determine if the results of the water column bioassays would meet the water column toxicity LPC for ocean placement. STFATE modeling was conducted assuming mechanical dredging and a maximum 20,000-cy discrete discharge volume. The input and output information for the Tier III STFATE modeling is provided in Attachment II.

The LPC for water column toxicity is the concentration that does not exceed 0.01 of the EC50/LC50 value within a 4-hour dilution period inside the boundary of the ocean placement site. If ammonia is a demonstrated toxicant, the LPC for water column toxicity is the concentration that does not exceed 0.05 of the EC50/LC50 value within a 4-hour dilution period inside the boundary of the ocean placement site.

In the water column, bioassays with A. bahia and M. beryllina had a LC50 values that were greater than 100 percent elutriate for each DU. Comparison of the untreated and ammonia-purged elutriate results for Mytilus sp. indicated that ammonia was the main constituent in the NSN Phase 1 elutriates contributing to water column toxicity. Therefore, the LPC for the water column toxicity is the concentration that does not exceed 0.05 of the LC50/EC50 value within a 4-hour allowable mixing period inside the boundary of the placement site.

Normal embryo development for Mytilus sp. in each of the untreated elutriates was statistically different (lower) than the laboratory control. A dilution ranging from 19- to 90-fold is required to meet the LPC for these samples. Results of the Tier III STFATE modeling (Table 20) for placement at the NODS indicated that the required dilutions would be achieved at distances ranging from 1,980 to 4,101 ft from the point of discharge. During the 4-hour mixing period, dilutions ranging from 119- to 133-fold would be achieved and the elutriate would travel a maximum distance of 4,384 ft from the point of discharge.

Based on the results of the water column bioassays and STFATE modeling, the elutriates from the NSN Phase 1 DUs meet the LPC for water column toxicity for placement at the NODS for a maximum discrete discharge volume of 20,000 cy.

5. BENTHIC DETERMINATIONS

a. Benthic Toxicity Evaluation. Whole sediment bioassays were conducted using two benthic species, Ampelisca abdita (marine amphipod) and Leptocheirus plumulosus (estuarine amphipod).

The tests were conducted as static, non-renewal tests with 10 days of exposure to the whole sediments and overlying water and measured survival in the NSN Phase 1 sediments as statistically compared to survival in the Willoughby Bank Reference Site subsurface sediment (WBREF- SUB). The test protocols are detailed in the SAP (EA 2022a), EA Ecotoxicology Laboratory Quality Assurance and Standard Operating Procedures Manual (EA 2022b), and Evaluation of Dredged Material for Ocean and Upland Placement: Naval Station Norfolk Phase 1– Maintenance Dredging, Norfolk, Virginia (EA 2023). Results for whole sediment bioassays are summarized in Table 21.

Dredged material does not meet the benthic toxicity LPC when mean test organism mortality:

Is statistically greater than in the reference sediment, AND

Exceeds mortality (or other appropriate end point) in the reference sediment by at least 10 percent (or 20 percentage points for amphipods).

Ampelisca abdita Survival in the sediments from the DUs ranged from 88 to 96 percent and were not significantly less than the survival in the WBREF-SUB sample (95 percent). Survival in the sediment samples was also within the percent allowable difference (20 percent for amphipods). The CBCON sample and the laboratory control had 90 and 95 percent survival at test termination, respectively.

Leptocheirus plumulosus Survival in the sediments from the DUs ranged from 92 to 98 percent. The WBREF-SUB sample had 93 percent survival. Survival in the sediment samples was within the allowable percent difference (20 percent for amphipods). The CBCON sample and the laboratory control had 94 and 95 percent survival at test termination, respectively.

LPC Compliance Survival in the whole sediment bioassays was not statistically different from the subsurface sample from Willoughby Bank Reference Site for either A. abdita or L. plumulosus. Therefore, the NSN Phase 1 sediments meet the LPC for benthic toxicity for placement at the NODS.

b. Benthic Bioaccumulation. Sediment from the NSN Phase 1 project area was evaluated in 28-day bioaccumulation studies with Nereis virens (sand worm) and Tapes japonica (manila clam). The studies measured survival of the test organisms and the potential for bioaccumulation of contaminants in organism tissue as a result of exposure to NSN Phase 1 sediment composites samples. The bioaccumulation exposure and chemical testing protocols are detailed in the SAP (EA 2022a) and in Evaluation of Dredged Material for Ocean and Upland Placement: Naval Station Norfolk Maintenance Dredging – Phase 1, Norfolk, Virginia (EA 2023). Results of the benthic bioaccumulation survival/recovery are provided in Table 22.

Tissue Contaminant Analysis Following review of the bulk sediment data and completion of the 28-day bioaccumulation exposures, USACE Norfolk District consulted with USEPA Region 3 to determine the target constituents of concern for tissue analysis. USACE Norfolk District and USEPA Region 3 requested that NSN Phase 1 tissue samples be analyzed for metals, dioxin/furan congeners, PAHs, pesticides (DDT series only), select SVOCs (benzoic acid, dibenzofuran, di-n-butyl phthalate, and phenol only), lipids, and percent moisture (EA 2023). Pre-test and WBREF-SUB tissues were also analyzed.

Detected concentrations of nonpolar organic constituents (dioxin/furan congeners, PAHs, pesticides [DDT series only], and SVOCs [benzoic acid, dibenzofuran, di-n-butyl phthalate, and phenol only]) were lipid-normalized to account for partitioning of organic chemicals within organism tissue to facilitate comparison of data from different tissue replicates and comparisons to reference tissue and pre-test tissue concentrations.

Tissue Chemistry Results Details of the data analysis and statistical methods are provided in Evaluation of Dredged Material for Ocean and Upland Placement: Naval Station Norfolk Maintenance Dredging – Phase 1, Norfolk, Virginia (EA 2023). Results of the tissue analysis for N. virens and T. japonica are summarized in Tables 23 through 27. Pre-test tissue concentrations that compare pre-exposure tissue concentrations to post-exposure concentrations are also provided in Tables 23 through 27.

The 95 percent upper confidence level of the mean (UCLM) tissue-residue concentrations for metals in worm and clam tissues exposed to the sediments from the NSN Phase 1 DUs were compared to U.S. Food and Drug Administration (USFDA) Values (USFDA 2001) (Table 28).

Dredged material does not meet the benthic bioaccumulation LPC if the tissue concentrations are statistically greater than USFDA Action/Guidance/Tolerance Levels. None of the UCLM values for NSN Phase 1 DU tissues exceeded the USFDA Action/Guidance/Tolerance Values for either metals or 4,4’-DDT (Table 28). There are no available USFDA Action/Guidance/Tolerance Levels for dioxin and furan congeners, PAHs, or SVOCs.

When tissue concentrations of contaminants of concern in organisms exposed to dredged material statistically exceed those of organisms exposed to the reference material, the dredged material has the potential to result in benthic bioaccumulation of contaminants. If the tissue concentrations statistically exceed those of organisms exposed to the reference site, the tissue concentrations are further evaluated to determine if placement of dredged material is likely to cause adverse effects.

Mean concentrations of analytes detected in the tissue samples exposed to sediment from the NSN Phase 1 DUs were statistically compared to the mean concentrations of analytes detected in the tissue exposed to subsurface sediment from the Willoughby Bank Reference Site (WBREF-SUB) to evaluate the potential for adverse impacts. If the mean tissue concentrations statistically exceeded mean reference site concentrations and mean pre-test tissue concentrations, then mean concentrations were:

Statistically compared to USEPA Region 4 Background Tissue Concentrations for the South Atlantic Bight (USEPA/USACE 2008), and

Evaluated for analytical variability within the data set (reporting limiting substitutions for non-detected data, outliers, and compliance with laboratory quality assurance/quality control requirements).

None of the UCLM values for the Phase 1 NSN maintenance dredging…