25B5002 - Appendix C - EPA concurrence.pdf

November 8, 2023

Ms. Lesley Dobbins-Noble, Chief Operations Branch Norfolk District, U.S. Army Corps of Engineers 803 Front Street Norfolk, VA 23510-1096 Dear Ms. Dobbins-Noble:

Thank you for your October 2, 2023 request for concurrence on the suitability for ocean disposal of dredged material from the Craney Island Eastward Expansion (CIEE) Project, specifically the southern expansion portion of the Pre-Dredge and Access Areas that is planned to be dredged during Phase 1c, 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 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 U.S. Army Corps of Engineers (USACE) Norfolk District is considering new work dredging from the CIEE Pre-Dredge Area, as evaluated in the 2009 Supplemental Environmental Assessment. The CIEE Pre-Dredge Area is comprised of 522 acres on the eastern side of Craney Island Dredged Material Management Area (CIDMMA) facility, a 2,500-acre confined dredged material disposal facility, located in Portsmouth, Virginia. Approximately 3 million cubic yards (mcy) of new work material is anticipated to be removed from the CIEE Pre-Dredge Area. Dredged material from the new work dredging accomplished during Phase 1c is proposed for placement 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 CIEE Pre-Dredge Area 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 the southern portion of the CIEE Pre-Dredge Area consisted primarily of fine-grained materials, consisting of 61.9% to 87.6% silt and clay, in the surface dredging units (DUs).

Sediments collected from the subsurface DUs were also comprised primarily of fine-grained materials, consisting of 94.5% to 98.3% silt and clay. The physical characteristics of sediments in the surface and subsurface DUs were most similar to those in the subsurface sample from Willoughby Bank Reference Site, which was comprised of 79.3% silt and clay. For this project, a total of 42 discrete locations were sampled to develop 14 DUs (6 surface and 8 subsurface DUs). Per sediment sampling, metals, PCB congeners, PAHs, SVOCs, and dioxin/furan congeners were detected above the laboratory reporting limit (RL). Arsenic and nickel exceeded the threshold effects level (TEL). Fourteen individual PAHs were detected in the surface composite sample sediments, but not in the subsurface composite samples.

The dioxin toxicity equivalency quotient (TEQs) exceeded the interim sediment quality guidelines (SQG) (0.85 ng/kg) by factors ranging from 5.42 to 16. Two SVOCs (benzyl alcohol and di-n-butyl phthalate) were detected in the composite samples, but at concentrations below the RL.

Standard elutriates (14), 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 1.02 – 2.66. Cyanide exceeded WQC for aquatic life in one subsurface elutriates by a factor ranging from 8.5; however, the laboratory reporting limit (RL) for cyanide exceeded by a factor of 10. Although cyanide was not detected 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 327-fold to 374-fold in the surface DUs and 363-fold to 388-fold in the subsurface DUs 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 3,818 ft from the location of discharge during the 4-hour mixing period.

Based on the above information, the standard elutriates from the CIEE Pre-Dredge Area 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 galloprovincialis (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 M. galloprovincialis tests measured developmental effects to embryos, and the A. bahia and M. beryllina tests measured effects to organism survival.

The 48-hr EC50 values in the untreated M. galloprovincialis elutriates in the surface DUs ranged from 44.6% to >100% and normal embryo development in the 100% untreated elutriates ranged from 0 to 77%. The laboratory controls had normal embryo development that ranged from 81 to 84% and the site water sample had 85% normal embryo development. Using ammonia-urged sediment, the 48-hr EC50 values were >100% elutriate with normal development in the 100% elutriates ranging from 75 to 88%. Normal development in one DU (SURF-DU3) was at least 10% less than and statistically different from the laboratory controls, which ranged from 80% to 90%.

The 48-hr EC50 values in the untreated M. galloprovincialis elutriates in the subsurface DUs ranged from 23.7% to 57.8% and normal embryo development in the 100% untreated elutriates ranged from 0 to 4%. For each of the elutriates created using ammonia-purged sediment, the 48-hr EC50 values were >100% elutriate with normal development in the 100% elutriates ranging from 76 to 88%. Normal development was not statistically different than the laboratory controls, which ranged from 81 to 90%.

A. bahia and M. beryllina both had a 96-hr LC50 of >100% elutriate for each sample. A. bahia survival in the 100% elutriates ranged from 90% to 100% in the surface DUs and 94% to 100% in the subsurface DUs. M. beryllina survival in the 100% elutriates ranged from 82% to 100% in the surface DUs and 74% to 100% in the subsurface DUs. One elutriate from DU12 was at least 10% different from the laboratory control. However, in the remaining DUs for both species, survival was not significantly different from the laboratory control, indicating that those 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 CIEE Pre-Dredge Area elutriates contributing to water column toxicity based on the comparison of untreated and ammonia-purged elutriate results, a dilution of 19- to 44-fold is required to meet the LPC for surface samples and 34- to 83-fold is required to meet the LPC for subsurface samples.

Results of the STFATE modeling for placement at NODS indicated that the required dilutions would be achieved at distances ranging from 566 to 1,273 ft from the point of discharge for the surface samples and 990 to 1,679 ft for the subsurface samples. During the 4-hour mixing period, dilutions ranging from 327- to 374-fold would be achieved for the surface samples and 363- to 388-fold for the subsurface samples. The elutriate would travel a maximum distance of 3,818 ft from the point of discharge.

Based on the results of the water column bioassays and STFATE modeling, the CIEE Pre-Dredge Area 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, Americamysis bahia abdita (opossum shrimp) and

Leptocheirus plumulosus (estuarine amphipod) were exposed to the CIEE Pre-Dredge Area sediment and overlying water to determine survival outcomes as statistically compared to survival in the Willoughby Bank Reference Site subsurface sediment.

A. abdita survival in CIEE Pre-Dredge Area sediments ranged from 96% to 99% in the surface DUs and 95% to 99% in the subsurface DUs. L. plumulosus survival in CIEE Pre-Dredge Area sediments ranged from 89% to 94% in the surface DUs and 87% to 92% in subsurface DUs. Exposure to NSN Phase I sediments did not exceed the allowable percent difference (10%) of mortality from the reference sediment; therefore, CIEE Pre-Dredge Area sediments meet the LPC for benthic toxicity for placement at NODS.

Bioaccumulation Evaluation

To evaluate chronic exposure to CIEE Pre-Dredge Area sediments, a 28-day benthic bioaccumulation exposure study with Nereis virens (sand worm) and Macoma nasuta (blunt-nose 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, PCB congeners, select SVOCs (phenol only), lipids, and percent moisture and were statistically compared to the reference site.

In the surface DUs, 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 total PCBs. In DU5, the mean OCDF concentration in the worm tissue statistically exceeded both the mean reference concentration and the mean pre-test concentration. However, the mean dioxin Toxicity Equivalency Quotients (TEQ) for worms did not exceed the mean reference dioxin TEQ or the mean pre-test dioxin TEQ. For DU4, mean concentrations of PCB 153 and Total PCBs in the worm tissue statistically exceeded both the mean reference and pre-test tissues. However, the UCLM for total PCBs in the worm tissue did not exceed the USEPA background tissue concentration for the South Atlantic Bight. PAHs were not detected in the tissue samples.

None of the UCLM values for the CIEE Pre-Dredge Area subsurface DU tissues exceeded the USFDA Action/Guidance/Tolerance Levels for metals. For DU11, DU12, and DU13, mean concentrations of cadmium in clam tissue statistically exceeded mean reference site and pre-test tissue concentrations. However, the UCLM for cadmium in clam tissue for each DU did not exceed the USEPA background tissue concentrations for the South Atlantic Bight. The mean concentrations of dioxin/furan congeners and select SVOCs (phenol) in clam and worm tissue did not statistically exceed either reference or pre-test tissue concentrations.

Based on the assessment of chemical analyses performed on pre-test tissues and tissues exposed to sediment from the CIEE Pre-Dredge Area and Willoughby Bank subsurface reference sediments, it is anticipated that ocean placement of the dredged material from CIEE Pre-Dredge Area 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, CIEE Pre-Dredge Area 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 CIEE Pre-Dredge Area 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 USACE will maintain all data associated with the project; and

• USACE 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 November 8, 2023. Use of NODS after November 8, 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, Christine Mazzarella, Acting Chief Wetlands Branch, Water Division U.S. EPA Region 3