SCPA-VT-LIF Investigation Report.pdf

Investigation and Remediation Summary Report

Veterans Terminal Bulkhead Release Area

North Charleston, Charleston County, South Carolina

Date Prepared: January 3, 2020 SCPA Project No. CIF13EU02

Terracon Project No. EN197343

South Carolina Ports Authority Mount Pleasant, South Carolina

Prepared by:

Terracon Consultants, Inc.

North Charleston, South Carolina

Ter racon Consul tants , I nc . 1450 5th St . Wes t Nor th Char les ton, SC 29405 P 843-884-1234 F 843-884-9234 t er racon.com

January 3, 2020

South Carolina Ports Authority 200 Ports Authority Drive Mount Pleasant, South Carolina 29464

Attn: Mr. Mark Messersmith P: (843) 375-3102 E: mmessersmith@scspa.com

Re: Investigation and Remediation Summary Report South Carolina State Ports Authority Veterans Terminal/Bulkhead Release Area North Charleston, South Carolina SCPA Project No. CIF13EU02 Terracon Project No. EN197343

Dear Mr. Messersmith:

Terracon Consultants, Inc. (Terracon) is pleased to submit this Investigation and Remediation Summary Report for the above referenced project. Cleanup activities were initiated and performed in general accordance with Terracon Proposal PEN197246 dated July 3, 2019 and South Carolina Ports Authority’s contract dated July 29, 2019, Terracon’s Supplemental to Agreement for Services dated August 30, 2019, and SCPA contract dated September 30, 2019.

Please do not hesitate to contact me at (843) 884-1234 or at charlie.vernoy@terracon.com if you have any questions regarding this remedial investigation report.

Sincerely, Terracon Consultants, Inc.

Charlie Vernoy William S. Anderson, III. P.E.

Senior Scientist Senior Principal

Don Malone Senior Engineer

TABLE OF CONTENTS

Page No.

1.0 INTRODUCTION

1.1 Overview of Historical Site Investigation and Remediation Activities

1.2 Purpose and Objectives

1.3 Scope and Report Limitations

1.4 Reliance

2.0 PHYSICAL SETTING

2.1 Geological Information

2.1.1 Geology

2.1.2 Soils

2.1.3 Hydrogeology

2.2 Applicable Remedial Action Objectives

2.2.1 Remedial Action Objectives – Groundwater

2.2.2 Remedial Action Objectives – Soil

3.0 REMEDIAL INVESTIGATION METHODS

3.1 Soil and Groundwater Removal Action

3.2 Removal Action Objective

3.3 Area of Impact

3.4 Removal Action – Excavations

3.4.1 Utility Clearances

3.4.2 Daily Activities

3.5 Soil Excavation/Removal/Disposal

3.6 Waste Water Management

3.7 LIF Investigation

3.8 Grain-Size Analyses

3.9 Soil Sample Collection and Analytical Methods

3.10 Decontamination and Investigative Derived Wastes

3.10.1 Cleaning Procedures

3.10.2 Investigation Derived Wastes

3.11 Borehole Abandonment

3.12 Survey

4.0 INVESTIGATION RESULTS

4.1 Investigations by Columbia Technologies

4.1.1 LIF/UVOST® Investigation Results

4.1.2 HPT Investigation Results

4.2 Grain-Size Analyses of Soil

4.3 Soil Sample Results

4.4 LNAPL Residual Saturation Results

4.5 3D-Visualization Results

5.0 CONCLUSIONS AND RECOMMENDATIONS

5.1 Conclusions

5.2 Recommendations

6.0 REFERENCES

TABLES

Table 1 – Grain Size Analyses Table 2 – Soil Analytical Methods and Sample Storage Table 3 – LIF/UVOST Boring Locations Table 4 – Chemical Constituents Detected in Soil Samples in October 2019

FIGURES

Exhibit 1 – 1983 Charleston Quad, SC USGS Topographic Map Exhibit 2 – Veterans Terminal Bulkhead Release Area Exhibit 3 – Excavation Area / Pipe, Waste, and Sample Locations Exhibit 4 – Suspected Impacted Areas Exhibit 5 – Ground Penetrating Radar Geophysical Evaluation Exhibit 6 – LIF Boring and Soil Sample Locations

APPENDICES

Appendix A – Photographic Log Appendix B – Field Notes Appendix C – Columbia Technologies High-Resolution Site Evaluation Report Appendix D – Particle Size Distribution Reports Appendix E – Laboratory Analytical Reports Appendix F – LNAPL Residual Saturation Appendix G – 3D Visualization Figures

Investigation and Remediation Summary Report Veterans Terminal Bulkhead Release Area January 3, 2020 ■ Terracon Project No. EN197343

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1.0 INTRODUCTION

The Veterans Terminal (VT) Bulkhead Release Area is located at the former Charleston Naval Complex (CNC) adjacent to the Cooper River at 1150 North Port Drive in North Charleston, South Carolina. A vicinity map (Exhibit 1) and site map (Exhibit 2) show the location of VT Bulkhead Release Area. The VT complex is a 110 acre fully secured dedicated bulk, break-bulk, Roll On-Roll Off cargo facility. The South Carolina State Ports Authority (SCPA) began leasing the facility from the Charleston Naval Complex Redevelopment Authority in 1999. The bulkhead between Piers Mike and November collapsed in October 2012.

1.1 Overview of Historical Site Investigation and Remediation Activities In December 2013, Terracon Consultants, Inc. (Terracon) conducted remedial action activities to remove petroleum contaminated soil and residual petroleum hydrocarbons within the VT Bulkhead Release Area. During the excavation activities, Terracon identified several pipes with petroleum seeping into the surrounding soil (Exhibit 3). Terracon conducted remedial abatement activities from December 26 through December 30, 2013 to remove contaminated soil, residual petroleum hydrocarbons, and impacted groundwater from the site. Approximately 970 tons of contaminated soil was excavated and transported to a permitted landfill for proper disposal. Approximately 3,700 cubic yards of clean back fill material was transported to the area and used as backfill for the excavation.

Approximately 30,000 gallons of tidal water and small quantities free-phase petroleum product was removed from the excavation area and properly disposed offsite. No petroleum was observed migrating into the Cooper River during the excavation activities. The results from these activities were summarized in Terracon’s Fuel Investigation Study report dated September 22, 2014. The approximate extents of excavation are in Exhibit 3.

The petroleum fuel was characterized as a middle distillate range fuel oil according to a fuel aging report by Texas Oil Tech Laboratories, Inc. Methyl- and dimethyl-napththelenes were the primary components of the fuel, with low concentrations of toluene and xylenes, which lead to the determination that the fuel was an old, weathered diesel fuel. The laboratory identified no significant signs of gasoline, anti-freeze coolants, brake fluids, motor oils, or other contaminating chemicals in the product.

In response to possible future excavation and construction activities at VT Bulkhead Release Area, the South Carolina Department of Health and Environmental Control (SCDHEC) requested a Soil and Groundwater Management Plan (SGMP) be developed to manage the contaminated soil and groundwater. Terracon developed the SGMP in October 2015.

In February 2019, Terracon conducted a Subsurface and Sediment Investigation (SSI) at the VT Bulkhead Release Area to address potential petroleum-impacted soil and groundwater, delineate the extent of contamination, and identify potential pathways of migration, potential receptors, and associated exposure pathways. Findings of the SSI report concluded the remaining area with petroleum-impacts was located on the western portion of the site. This area was identified during

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Based on the results of the SSI, Terracon recommended excavation and disposal of petroleum-impacted soil in the area depicted on Exhibit 4. The removal action was necessary to address contaminated soils and free-product petroleum at depths of approximately 4 to 9 feet below land surface (bls). The removal action was conducted in accordance with the SGMP that provided details on the handling, testing, containment, removal, and disposal of contaminated soils and containment and disposal of contaminated groundwater. Terracon implemented the excavation activities recommended in the SGMP from July 30 through August 9, 2019. Petroleum impacted soil, groundwater, and tidal water was removed from the VT Bulkhead Release Area. Section 3 summarizes the results of the removal action.

The investigations and removal actions conducted from December 2013 through August 2019 effectively remediated the majority of the petroleum-impacted soil, and free-phase petroleum previously identified at the site.

1.2 Purpose and Objectives

Terracon initiated additional remedial investigation activities at the VT Bulkhead Release Area in October 2019 to further define the extent of petroleum-impacted soil and to assess whether additional remedial strategies would be required to achieve applicable remedial action objectives (RAOs) for the site. The purposes of this report are to describe the methods used, summarize results of the site investigations activities, and recommend a pathway to closure for petroleum impacts at the site.

1.3 Scope and Report Limitations

The findings and conclusions presented in this Remedial Investigation report are based solely upon the data and information obtained and reviewed through the agreed-on scope of services, as outlined in Terracon Proposal dated July 3, 2019, SCPA’s contract dated July 29, 2019, Terracon’s Supplemental to Agreement for Services dated August 30, 2019, Terracon’s Supplemental to Agreement for Services dated August 30, 2019, and SCPA contract dated September 30, 2019.

Such information is subject to change over time and we cannot represent any site conditions beyond those specifically identified through Terracon’s scope of services. Terracon makes no warranties, express or implied, with regard to professional services, associated findings, or any third-party information used in connection with this project. These limitations must be considered when the user of this report formulates opinions as to risks in connection with the site or uses the report for any other purpose.

1.4 Reliance

This report has been prepared for the SCPA. Use or reliance by any other party (except a governmental entity having jurisdiction over the site) is prohibited without the written authorization of

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2.0 PHYSICAL SETTING

2.1 Geological Information

According to the Resource Conservation and Recovery Act Facility Investigation (RFI) Report dated February 20, 1998, VT is located within the boundaries of the Zone G at the former CNC. The RFI report provided a detailed explanation of the geology, soils, and hydrogeology for the area. The following are summations from the report.

2.1.1 Geology

According to the RFI Report, Tertiary-Age (Ta) and Quaternary-Age (Qa) sediments were encountered during the Zone G RFI. Ta sediments, commonly referred as the Ashley formation, is the youngest member of the Eocene-Oligocene age Cooper Group. The Ta was deposited in an open-marine shelf environment during a rise in sea level in the late Oligocene. Ta sediments were encountered at elevations ranging from -16.6 feet mean sea level (ft msl) to -49 ft msl. The report states that there are four TA units placed stratigraphically above the Ta. These units are called the Chandler Bridge, Edisto, Marks Head, and Goose Creek Limestone formations. The report grouped these units as undifferentiated Upper Tertiary.

Qa sediments are part of the Quaternary Period and began with the Pleistocene Epoch and continue with the recent Holocene Epoch. Several marine transgressions-regression sequences occurred that resulted in a complex network of terraces composed of coastal depositional environments such as barrier islands, back-barrier lagoons, tidal inlets, and shallow marine shelf systems. Throughout Zone G, Qa sediments were observed from the top of the Ta sediments to the surface. These sediments comprise the Pleistocene-age Wando Formation.

2.1.2 Soils

According to the RFI Report, the upper five feet of the subsurface are typically a mixture of fill and native sediments. The report further states that the extent of fill placement varies throughout the former CNC, areas of excavation or areas where native soils may been unsuitable for foundation support may have undergone extensive fill placement. Fill included materials dredged from the Cooper River and Shipyard Creek and contained a mixture of sands, silts, and clays. The RFI Report stated average grain-size distribution was 81% sand, 7% silt, and 12% clay.

2.1.3 Hydrogeology

According to the RFI Report, the surficial aquifer extends from the water table to the top of the Ta, which serves as a regional confining unit, and ranges from 25 to 55 feet. The report stated groundwater flow from Zone G generally flows towards the Cooper River with groundwater elevation typically around 6 feet.

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2.2 Applicable Remedial Action Objectives

2.2.1 Remedial Action Objectives – Groundwater

Terracon understands the absence of free product is the primary RAO for total petroleum hydrocarbons in groundwater at VT. The determination of the absence of free product is assessed typically using monitoring wells.

2.2.2 Remedial Action Objectives – Soil

The SCDHEC adopted the U.S. Environmental Protection Agency (USEPA) Regional Screening Levels (RSL) as RAOs for soil. Terracon obtained the most current RSLs for the site based on the USEPA RSL Generic Tables (updated May 2019) based on a target cancer risk (TR) of 1E-06 and a target hazard quotient of 1.0. Terracon considers the following RAOs as the benchmark for determining whether petroleum hydrocarbon impacts at a site require remediation:

§ Total Petroleum Hydrocarbons (TPH) Diesel Range Organics (DRO) based on “Medium Aromatics” (C9-C16) such as 2-methyl naphthalene / naphthalene: 600 milligrams per kilogram (mg/kg)

§ TPH-DRO based on “High Aromatics” (C17-C32) such as fluoranthene:

33,000 mg/kg

§ TPH Oil Range Organics (ORO) based on “Medium Aliphatics” (C9-C18) such as hydrocarbon streams:

440 mg/kg

§ TPH-ORO based on “High Aliphatics” (C19-C32) such as mineral oils: 350,000 mg/kg.

The most applicable ROAs for TPH-DRO are the “High Aromatic” (i.e., C17-C32) because 2-methyl naphthalene and naphthalene are absent in soil samples from the site and based on historical Navy information on the types of fuel used at the former Naval Complex.

3.0 REMEDIAL INVESTIGATION METHODS

In July and August 2019, Terracon and its subcontractors conducted a soil and groundwater removal action in response to petroleum impacted soils in the Bulkhead Release Area. In October 2019, Terracon and its subcontractors conducted a high-resolution site characterization at the site, using a combination of Laser Induced Fluorescence (LIF) - Ultraviolet Optical Scanning Tool (UVOST®) and Geoprobe Systems® Hydraulic Profiling Tool (HPT). The following sections provides details to the activities performed. A photo log for some of the key aspects of the work are in Appendix A. Field notes are in Appendix B.

3.1 Soil and Groundwater Removal Action

Terracon conducted a removal action for petroleum impacted soil and groundwater in the Bulkhead Release Area from July 30 through August 9, 2019. The removal action was necessary to address contaminated soils and petroleum free product at depths of approximately four (4) to nine (9) feet bls discovered during test pit excavations conducted on February 20 and 21, 2019. During the February

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2019 test pit excavation activities, twenty test pits were excavated across the excavation area.

Subsurface soil profiles were consistent with regional geology and soil types. A 1 foot to 1.5 foot stone and gravel layer was on the ground surface followed by 0.5 foot of asphalt. A brown/tan sandy loam layer is generally at 2 to 4 feet followed by gray/black clay.

3.2 Removal Action Objective

Based on the findings from the February 2019 test pit excavations, a remedial action for contaminated soil was initiated. The RAO was to prevent on-site exposure through ingestion, inhalation, and direct contact of soil and groundwater contaminated with petroleum related hazardous constituents to future site workers and potential migration to the Cooper River of hazardous constituents. Terracon proposed the following scope of work for the soil removal action:

§ Site preparation activities, including marking of removal areas based on previous test pit excavations, delivery and set-up of pumps, frac tanks, and vacuum truck for the collection of contaminated waste water.

§ Proper documentation of field observations, including field logbook, photographs of field activities, and chain of custody records for environmental samples.

§ Excavation, removal, and proper disposal of contaminated soil and groundwater.

§ Confirmatory soil sampling and analysis to confirm RAO was achieved.

§ Characterization of collected wastewater from frac tanks for proper disposal.

§ Delivery and stockpile of clean fill material to excavation area and backfill and site restoration.

§ Reporting.

3.3 Area of Impact

The excavation area was located to the southwest of the bulkhead release between Piers Mike and November. Based on test pit excavations activities, petroleum contaminated soil was believed to be at a depth of 3 feet to 9 feet bls with free product observed floating on groundwater at approximately 6 feet. Exhibit 3 outlines the proposed excavation area based on data collected during the test pit excavations in February 2019.

3.4 Removal Action – Excavations

3.4.1 Utility Clearances

A multifrequency electromagnetic and ground penetrating radar (GPR) geophysical evaluation was conducted at the site on July 30, 2019 prior to commencement of excavation activities to identify possible anomalies within the excavation area where pipes may be buried. The GPR results identified previous anomalies (northern and western areas of 2013 excavation) where pipes were found during the 2013 excavation activities. The anomalies identified in the southern portion of the July/August 2019 excavation are in the general area of where pipes were found during the most recent excavation activities. Exhibit 5 illustrates the results of the GPR evaluation.

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3.4.2 Daily Activities

Wednesday 07/31/2019 Terracon met subcontractors on-site on Wednesday July 31, 2019. A site safety/site kick-off meeting was held and soil removal action activities were initiated. Soil ground break was initiated in the upper right quadrant of the impacted area. Terracon screened soil at approximately 1-foot intervals with the photoionization detector (PID) meter to determine baseline soil contamination detections.

PID reading for contaminated soil ranged from 90-200 + parts per million (ppm). Contaminated soil was excavated and transported off-site by trucks and disposed of at an excepted disposal facility.

Excavation activities ceased along the eastern edge due to concerns of possible tidal influence.

Excavation continued at the center and southern portions of the impacted area. PID readings detected contaminated soil at 3-5 feet bls to depths of 10-12 feet bls. Trucks brought in clean soil and placed in an adjacent stockpile while contaminated soil, determined by PID readings, was placed in a soil contaminant area constructed of hay bales and black plastic tarp. Tidal water influence was identified at approximately 4-5 feet below ground surface. When excavation ended for the day, an orange caution fence was placed around the open excavation pit.

Thursday 08/01/2019 Excavation of the pit continued and elevated PID readings were observed. Contaminated soil was excavated and transported off-site by trucks and disposed of at an excepted disposal facility. Tidal water influence flushed residual contamination into the excavation pit and a visible sheen was observed inside the excavation pit. Impacted water from the excavation pit was vacuumed and transferred to frac tanks on site so excavation could continue. Three underground and open-ended suspected fuel pipelines were uncovered in the middle portion of the excavation pit at approximately 6-7 feet below ground surface. Pipes appeared to have been previously cut. One large pipe was observed to be filled at the end with clay material. Attempts were made to cap the open ends of the pipes, but tidal water had begun to flow through some of the pipes and capping was only completed for one of the pipes and the remaining pipes could not be capped. The open pipes contributed to the influx of tidal water as the tide rose.

The wall along the eastern portion of the pit adjacent to the river was reinforced to protect against tidal influence. Water that collected in the excavation during the night was vacuumed and transferred to frac tanks on site by the response team.

Friday 08/02/2019 Excavating stock piled soil and disposal. Personnel attempted to cap the largest pipe in the excavation area; however, tidal water coming through the pipes would not allow the hydraulic cement material to bind. Excavation was halted due to the tidal influence and personnel inside the pit. As the high tide cycle approached it was determined to wait until the low tide cycle and attempt to cap the pipes. Impacted water in the excavation area was vacuumed and transferred into the frac tanks between the high and low tidal cycles. Response team would remain onsite to vacuum tidal water that entered the excavation pit.

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Decision was made to shore the eastern wall with clean fill on August 3rd and to prevent further inundation of tidal water into the excavation area

Saturday 08/03/2019 Remediation crew began construction activities to stabilize the eastern wall and partially fill in the eastern portion of the excavation area to prevent inundation of tidal water. Personnel remained on site to vacuum groundwater that seeped into the open excavation area. During stabilizing activities, a leak was observed emanating from the largest pipe.

Sunday 08/04/2019 Personnel periodically vacuumed water from excavation area.

Monday 08/05/2019 Excavation of the pit continued. Contaminated soil was continuing to be identified outside the expected excavation pit boundaries. However, excavation activities were discontinued on advice from Terracon site personnel due to tidal water intrusion into the excavation area since the walls of the excavation and the proximity to the narrow dike wall protecting the site from tidal water intrusion was being compromised. It was recommended by Terracon to SCPA to abandoned further excavation activities because of increased tidal water intrusion. During a low tidal cycle, pipe that was leaking had a metal cap welded to the end to prevent further tidal water intrusion

Wednesday 08/07/2019 – Friday 08/09/2019 Terracon and subcontractors were on site Wednesday through Friday performing filling and observation well installation activities. The excavation pit was back-filled with available gravel and soil at the site. Three observation wells were installed on the southern, central and northern portions of the excavation area, respectively. Filling of the excavation pit consisted of stone aggregate from approximately 12 - 3 feet below surface grade. Bentonite was constructed around the perimeter of the remediation well at approximately 3 - 2 feet below ground surface. Clean backfilled soil was placed from approximately 2 – 0 feet below ground surface. All activities ended on Friday 08/08/2019 at approximately 12:00PM.

Friday 08/16/2019 Terracon personnel arrived on site to check the three observation wells for any indication of free product layer in the wells. A water level meter with an interface probe was used for measuring free product in the wells. Free product was not observed in any of the wells.

3.5 Soil Excavation/Removal/Disposal

Approximately 950 tons of contaminated soil was excavated and transported to Oak Ridge Landfill in Dorchester County for proper disposal. Approximately 530 cubic yards of clean back fill material was transported to the area and used for backfill.

3.6 Waste Water Management

Four frac tanks were filled during excavation activities. Approximately 168,000 gallons of tidal water

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3.7 LIF Investigation

In response to the soil removal action conducted in August, Terracon was tasked to screen remedial action alternatives based on effectiveness at remedy completion as defined by SCDHEC. Because the extent of contamination at VT encompassed a potentially larger area than originally scoped, Terracon proposed a laser induced fluorescence (LIF) study to define the nature and extent of light non-aqueous phase liquid (LNAPL) contamination at VT. Columbia Technologies provided the LIF equipment and SADAECCO provided the direct push technology (DPT) services (Geoprobe) for the LIF study. The Geoprobe was equipped with the following sensors:

n Optical Imaging Tool (OIP) with an Ultraviolet Light (UV) detector – to delineate non-aqueous phase liquid (NAPL) hydrocarbon fuels and oils;

n Hydraulic Profiling Tool (HPT) – to determine pore-level hydraulic conductivity of the shallow aquifer formation, which is used to infer lithologic conditions beneath the site; and n Membrane-Interface Probe (MIP) – to measure volatile hydrocarbon and solvent contamination along with soil electrical conductance and permeability.

Columbia Technologies started near the former excavation, and then proceeded with DPT OIP-UV borings spacings of approximately 50 feet until the LNAPL extents were reasonably defined laterally and vertically. At that point, Columbia Technologies switched the tooling to utilize the combined HPT/MIP to more adequately map the lithologic conditions beneath the site (HPT), and the higher- TPH concentrations in soil and groundwater (MIP) not detected by the OIP-UV sensor.

The High-Resolution Site Evaluation Report from Columbia Technologies in Appendix C provides a detailed explanation of the sensors used in the study.

3.8 Grain-Size Analyses

The grain size analysis is used in classification of soils. Information obtained from grain size analysis can be used to predict soil water movement although permeability tests are more generally used.

Terracon submitted four soil samples for determination of grain size distribution. Section 4.2 discusses the results of the grain size analyses. Table 1 below provides the results of the analyses.

Table 1 – Grain Size Analyses

Sample ID % Sand % Fines

Coarse Fine Silt Clay L-05 43.3 41.0 14.1 0.6 L-09 5.4 40.1 6.5 0.4 L-15 47.4 51.4 1.2 0.0 L-26 2.9 13.2 27.7 15.7

3.9 Soil Sample Collection and Analytical Methods

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Eight soil samples were collected from the LIF/MIP study area and submitted for laboratory analysis confirmation in response to LIF readings. The field project manager reviewed the LIF results to make the final decision on the samples submitted for laboratory submission. Discrete soil samples were collected using a Geoprobe® rig utilizing direct-push technology. Soil borings were advanced based on LIF readings.

Soil samples were collected immediately following retrieval to maintain sample integrity. The sample was placed directly into laboratory-supplied containers and immediately placed on ice in the designated sample cooler. Each soil sample had a specific identification that provided information related to the location of the sample. For example, a sample ID of “L-04” would represent the following collection location:

§ L = LIF; and

§ 4 = soil sample location.

A sample ID such as L-04-A or B would be:

n A = designated for Total Petroleum Hydrocarbons (TPH) Diesel Range Organics (DRO)/Oil Range Organics (ORO) and Polynuclear Aromatic Hydrocarbon (PAH) analyses n B = designated for TPH DRO/ORO analyses only

Sample containers were labeled with sample-specific identifiers (e.g., sample ID, date, time, etc.)

prior to sample collection, sealed, and immediately placed on ice in designated sample coolers for potential laboratory submission.

Soil samples were collected and handled consistent with standard industry practice and applicable USEPA sampling protocols. Signed chain-of-custody documentation accompanied the sample coolers at all times consistent with laboratory and USEPA SW-843 protocols and Terracon SOP E.30

– Chain of Custody Documentation.

Table 2 outlines the soil sample containers specific to each analytical method and summarizes associated preservation and storage parameters. General sample handling, storage/shipping, and chain-of-custody procedures are further discussed in the QAPP. Laboratory soil samples were submitted to Shealy Environmental Services, Inc. of West Columbia, South Carolina, a SCDHEC certified laboratory.

Table 2 – Soil Analytical Methods and Sample Storage

Analysis Analytical Method Container/Storage Preservative Holding Time

PAHs 8270C

1 x 4 oz. glass jar; cool to 4° Celsius

None 14 days to extract, 40 days to analyze

TPH - DRO 8015C

1 x 4 oz. glass jar; cool to

4° Celsius None

14 days to extract, 40 days to analyze

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Analysis Analytical Method Container/Storage Preservative Holding Time

TPH - ORO 8015C

1 x 4 oz. glass jar; cool to

4° Celsius None

14 days to extract, 40 days to analyze

Notes:

PAHs Polynuclear aromatic hydrocarbons TPH Total petroleum hydrocarbons DRO Diesel range organics ORO Oil range organics

3.10 Decontamination and Investigative Derived Wastes

3.10.1 Cleaning Procedures

Sampling equipment was cleaned and decontaminated consistently to further maintain sample quality. Non-dedicated equipment in contact with potentially contaminated media was not reused prior to decontamination in accordance with procedures outlined below.

Equipment decontamination consisted of Alconox® solution cleaning using a stainless steel or nylon brush, followed by a potable and distilled water rinses. Field personnel wore disposable gloves during the process to increase personal protection and prevent potential cross-contamination.

The following Terracon SOPs were applied as general guidance for equipment cleaning procedures not specifically addressed above:

§ E.2405 – Cleaning - General § E.2410 – Cleaning - Manual Washing

3.10.2 Investigation Derived Wastes

Investigative derived wastes (IDW) were managed accordingly to maintain existing site conditions and prevent increased exposure risks. Associated procedures were designed to meet the following management objectives:

§ Leave the site in no worse condition than prior to the characterization

§ Remove wastes that may threaten human health and the environment

§ Comply with federal, state, and local requirements

§ Minimize IDW volumes to the extent possible without compromising project objectives

Project IDW generally included:

§ Used personal protective equipment

§ Decon liquids

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Terracon arranged disposal of the containerized materials accordingly following review of the analytical results. Spent personal protective equipment (PPE) and disposal sampling equipment were disposed of as municipal solid waste.

3.11 Borehole Abandonment

Boreholes were properly abandoned to prevent its serving as a vertical conduit for movement of environmental impacts through soils. Soil cuttings were placed back in the borehole in the order that the soil was removed so that soil was returned to the approximate depth from which it originated.

3.12 Survey

A hand-held global positioning system was utilized to obtain coordinates for the test pit locations.

This information was incorporated into site drawings and may be used in tracking and storing site information in a geographic information system format.

4.0 INVESTIGATION RESULTS

4.1 Investigations by Columbia Technologies

Terracon staff provided oversight to Columbia Technologies (Columbia) and SAEDACCO personnel from October 28, 2019 to October 30, 2019 to perform high-resolution site characterization activities at the site, using a combination of LIF, UVOST®, HPT. The HPT tool measures a combination of HPT injection pressures versus average injection flow rates, estimated hydraulic conductivities, and estimated electrical conductivities. Columbia’s High Resolution Site Evaluation Report dated November 4, 2019 is in Appendix C. The horizontal and vertical locations of each boring are in Table 3 in Appendix C. The following summarizes the results from each investigational method.

4.1.1 LIF/UVOST® Investigation Results

Columbia installed 36 LIF/UVOST® borings (Station IDs L-01 through L-36) at the site, each to a depth of approximately 26 feet bls. The locations of the borings are illustrated in Exhibit 6. The greatest response values were obtained from the following borings/depths:

§ L-03 – max signal at 55 % relative response (RE) at 11 feet bls

§ L-04 – max signal at 50 % RE at 11 feet bls

§ L-07 – max signal at 58 % RE at 18 feet bls

§ L-09 – max signal at 52 % RE at 11 feet bls

§ L-17 – max signal at 88 % RE at 10 feet bls

§ L-26 – max signal at 69 % RE at 9 feet bls

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4.1.2 HPT Investigation Results

Columbia installed three HPT borings (Station IDs H01.MHP through H03.MHP) at the site, each to a depth of approximately 26 feet bls. The locations of the borings are in Exhibit 6. The injection pressures and average injection flow rates varied with depth depending on the resistance of the injected fluid entering the pore spaces between soil grains. In general, HPT injection pressures increased and average injection flow rates decreased when the tool advanced past finer-grained soils. Likewise, the injection pressures decreased and average injection flow rates increased when the tool advanced past courser-grained soils. The HPT software provided an estimate of hydraulic conductivity (K) for the more permeable units within the aquifer formation. The following is a summary of the K values based on the HPT logs in Appendix C:

§ H01.MHP – course-grained soils from 2 to 15 feet bls, no K-values obtained.

§ H02.MHP – course-grained soils from 10 to 15 feet bls with K-values ranging from 20 feet per day (ft/day) to greater than 75 ft/day (i.e., 7.1x10-3 to 2.6x10-2 centimeters per second [cm/sec]).

§ H03.MHP – course-grained soils from 4 to 15 feet bls with K-values ranging from 45 to >75 ft/day (i.e., 1.6x10-3 to 2.6x10-2 cm/sec).

These K-value ranges are representative of well-sorted medium sands (Fetter, 2001; Domenico & Schwartz, 1990).

4.2 Grain-Size Analyses of Soil

Terracon collected samples from select borings (L-5, L-9, L-15, and L-26) for grain-size analyses (Appendix D). Terracon utilized empirical relations (GroundwaterSoftware.com, 2019; Chapuis and Aubertin, 2003) to estimate K-values based on the grain size distribution of the samples. This correlation utilizes the Kozeny-Carman equation to relate the 10% cumulative passing (D10) from the test to calculate hydraulic conductivity based on particle density, dynamic viscosity of the fluid (water), and estimates for porosity. The soil samples were characterized as follows, based on these correlations:

§ L-5 – Coarse to fine sand, with silt (D10= 0.073 millimeters [mm], 4.3 ft/day or 1.5x10-3 cm/sec)

§ L-9 – Fine sand, with silt (D10= 0.092 mm, 6.8 ft/day or 2.4x10-3 cm/sec)

§ L-15 – Fine to coarse sand (D10= 0.21 mm, 35 ft/day or 1.3x10-2 cm/sec)

§ L-26 – Clayey-silt with fine sand (D10= <0.001 mm, <0.001 ft/day or <1x10-6 cm/sec)

These values corroborate with the soil descriptions and conductivity estimates from the HPT investigation results, excluding the value for sample L-26.

4.3 Soil Sample Results

Terracon collected eight soil samples (L-04-A, L-04-B, L-07, L-09-A, L-09-B, L-15, L-17, and L-25) for

January 3, 2020 ■ Terracon Project No. EN197343

Responsive ■ Resourceful ■ Reliable 13 laboratory analyses, based on the boring locations/depths with the greatest LIFs responses. The laboratory analytical reports are in Appendix E. Analytical results are in Table 4 in Appendix E.

Based on these data:

§ none of the polynuclear aromatic hydrocarbons (PAHs) exceeded the USEPA RSLs for industrial soil, § None of the samples with TPH-DRO detections exceeded the “High Aromatic” (C17-C32) USEPA RSL, which was based on fluoranthene.

§ None of the samples with TPH-ORO detections exceeded the “High Aliphatic” (C19-C32), which was based on mineral oils.

Based on these data, no-further action (NFA) status is applicable to the site based on the analytical results from soil samples and the absence of free product in site monitor wells.

4.4 LNAPL Residual Saturation Results

Terracon utilized the TPH and LIF data to evaluate the presence and migration potential of LNAPL at the site. When the LNAPL saturation approaches residual saturation levels, the LNAPL transmissivity approaches zero (Interstate Technology & Regulatory Council [ITRC], 2009). Using ITRC guidance, Terracon estimated the LNAPL saturations for eight soil samples based on TPH concentrations, porosity for sand (0.30), soil bulk density of sand (1.8 grams per cubic meter), and an assumed LNAPL specific gravity (0.85). The equations and resultant data are in Appendix F.

The saturation values ranged from approximately 0.93% to 4.9%. These saturation values are indicative of residual LNAPL (not mobile LNAPL); and thus, the migration potential of the TPH is highly unlikely. These are conservative values because the estimated saturations would be lower due to the higher porosities in fine-grained soils. Additionally, smaller relative permeabilities of finer-grained soils, and the greater densities and greater viscosities of weathered fuels, would further limit the potential for LNAPL migration.

4.5 3D-Visualization Results Terracon developed linear correlations to transform Columbia’s LIF data (in units of % relative response) into TPH concentrations (in units of mg/kg) to aid in our understanding of the vertical and horizontal extents of petroleum impacts that might exceed applicable USEPA RSLs. Terracon developed the correlations by developing LIF-to-TPH ratios for both fine-grained soils and coarse-grained soils. Terracon determined the USEPA RLS of 600 mg/kg TPH-DRO correlated with 2.5% LIF response, using the fine-grained soil correlation factor as a conservative assumption. None of the soil samples exceeded the USEPA RSLs for TPH-DRO (33,000 mg/kg) or for TPH-ORO (350,000 mg/kg). Therefore, we developed a second correlation based on an arbitrary RAO of 3,300 mg/kg TPH-DRO that equated to a 12.5% LIF response.

Terracon utilized 3-Dimensional Visualization (3D-Vis) Software to visualize the horizontal and vertical extents for both scenarios. The horizontal extents of impacts are shown, including correlations and graphical results from the 3D-Vis activities, are in Appendix G. Based on these data, the volume of soil that exceeded the RAO of 600 mg/kg TPH-DRO was estimated at 7,300 CY.

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The volume of soil that exceeded the RAO of 3,300 mg/kg TPH-DRO was estimated at 3,800 CY.

We developed these volume estimates in case soil excavation or in situ treatment should be performed. This work is not warranted at this time.

Based on the information contained in Sections 4.3 and 4.4, the remediation of soil and groundwater have been completed at the site to the extent practical and additional remedial measures are not warranted nor practical.

5.0 CONCLUSIONS AND RECOMMENDATIONS

5.1 Conclusions

The following summarizes the results from the prior and current site investigations and remedial actions for the site:

§ Site investigations activities occurred in several phases from December 2013 to present to define the extents of petroleum impacts in soil and groundwater

§ A fuel aging report from 2014 identified the free-product, initially present at the site, as an old, highly weathered diesel fuel

§ Soil excavation with off-site disposal occurred in phases in 2013 and 2019, which removed impacted soil containing residual and free-phase petroleum hydrocarbons

§ The high-resolution site characterization activities in October and November 2019 demonstrated:

o The continued absence of free-product in monitor wells o thorough definition of the residual product present in soil and groundwater beneath the site

§ No PAHs concentrations exceeded applicable USEPA RLs

§ No TPH-DRO and TPH-ORO concentrations exceeded applicable USEPA RLSs based on “High Aromatic” (C17-C32) ranges and “High Aliphatic” (C19-C32) ranges

§ Calculated residual saturation values for the TPH are indicative of residual LNAPL (not mobile LNAPL)

§ Groundwater gauging activities revealed the absence of free-product in monitor wells

5.2 Recommendations

The most appropriate RAO for petroleum hydrocarbons in soil at the site is TPH-ORO “High Aliphatic” (C19-C32) because volatile organic compounds and PAHs, typically in diesel fuel, were absent in the product samples from 2014 and 2019. PAH concentrations also are absent in soil samples collected from the site (less than applicable USEPA RSLs). Based on the information contained here, the remediation of soil and groundwater due to petroleum releases have been completed at the site to the extent practical. Therefore, we recommend to SCDHEC to review the NFA status of the site. Closure of the site is warranted based on the analytical results from soil samples and the absence of free product in site monitor wells.

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6.0 REFERENCES

Chapuis, Robert P. and Michel Aubertin, 2003. Predicting the Coefficient of Permeability of Soils using the Kozeny-Carman Equation, Department CGM, École Polytechnique de Montréal, Montreal, Canada. January.

Domenico, P.A. and F.W. Schwartz, 1990. Physical and Chemical Hydrogeology, John Wiley & Sons, New York.

Fetter, C.W., 2001. Applied Hydrogeology, Fourth Addition, Prentice Hall, Upper Saddle River, NJ.

GroundwaterSoftware.com, 2019, Calculator 6 - Hydraulic Conductivity - Kozeny Carmen, based example calculates in website obtained from http://www.groundwatersoftware.com/ calculator_6_hydraulic_conductivity.htm. December 12.

Interstate Technology & Regulatory Council (ITRC), 2009, Technical/Regulatory Guidance:

Evaluating LNAPL Remedial Technologies for Achieving Project Goals, Prepared by the ITRC LNAPLs Team.

December.

EXHIBITS

1450 Fifth Street West N.Charleston, SC 29405

Phone: 843.884.1234 Fax: 843.884.9234

EXHIBIT NO.

File Path:

Date:

PM:

Drawn By:

Checked By:

Approved By:

As Shown

Site

³ 0 0.75 1.50.375 Miles

1983 Charleston Quad, SC USGS Topographic MapProject No.

Scale:

Veterans Terminal Investigation and

Remediation Summary Report

CAV EN197343

JTM

CAV

CAV 2/6/14 Charleston County South Carolina

EXHIBIT NO.

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Date:

PM:

Drawn By:

Checked By:

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As Shown

Site

³ 0 100 20050 Feet

VeteransTerminal Bulkhead Release AreaProject No.

Scale:

Veterans Terminal Investigation and

Remediation Summary Report

CAV EN197343

JTM

CAV

CAV 2/6/14 Charleston County South Carolina

Legend Approximate_Site_Limits

EXHIBIT NO.

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Date:

PM:

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As Shown

!A

!A

!A

!A !A

!A

!A

Free product seeping from under concrete block at approx. 6' BGS

Free product bubbling out of end of pipe at approx. 6' BGS

Section of pipe removed and plugged

Free product seeping through soil at approx. 9' BGS

Free product seeping through soil at approx. 7.5' BGS

CS-4

CS-1 CS-2

CS-3

CS-5

Unk-1

CS-6

³ 0 25 5012.5 Feet

Excavation Area / Pipe, Waste, and Sample LocationsProject No.

Scale:

Veterans Terminal Investigation and

Remediation Summary Report

CAV EN197343

JTM

CAV

CAV 2/6/14 Charleston County South Carolina

Legend Approximate_Site_Limits

Approximate_excavation_area

!A Excavation Floor Samples

45 Degree Bent Pipe - Approx. 5' BGS

Capped Pipe - Approx. 4' BGS

Utility Pipe - Approx. 7' BGS

Concrete Block

Pipe Angled Towards Concrete Block

Free product seeping through soil

EXHIBIT NO.

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Approximately 0.05 Acres

Confirmatory Grid Sample Areas (~15'x17')

~35 Linear Feet

~6 0 L ine ar

Fe et

TP-9

TP-4

TP-5

TP-2 TP-3

TP-1

TP-6

TP-7

TP-8

TP-16

TP-15

TP-11

TP-12

TP-13

TP-14

TP-10

Source: Esri, DigitalGlobe, GeoEye, Earthstar Geographics, CNES/Airbus DS, USDA, USGS, AeroGRID, IGN, and the GIS User Community

³ 0 50 10025 Feet

Veterans Terminal Bulkead Release AreaProject No.

Scale:

Veterans Terminal Investigation and

Remediation Summary Report

Suspected Impacted Area

CAV EN197343

JTM

CAV

CAV 10/15/18 Charleston County South Carolina

Legend Approximate Site Limits

TP5, TP8, TP11 Area

Confirmatory Grid Sample Areas

") Test Pit

EXHIBIT NO.

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Date:

PM:

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As Shown

Source: Esri, DigitalGlobe, GeoEye, Earthstar Geographics, CNES/Airbus DS, USDA, USGS, AeroGRID, IGN, and the GIS User Community

³ 0 25 5012.5 Feet

Veterans Terminal Bulkead Release AreaProject No.

Scale:

Re V m et e e d ra ia n l s A T c e ti r o m n i n P a la l n 5

CAV EN197343

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CAV 10/3/2019 Charleston County South Carolina cavernoy Text Box Investigation and Remediation Summary Report

L01

L02

L03

L04

L05

L06

L07

L08

L09

L10

L11 L12

L13

L14

L15

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L25 L26

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L34

L35

L36

Project Mngr:

Approved By:

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Drawn By:

Project No.

Scale:

Date:

File Name: Consulting Engineers and Scientists

Exhibit

2401 Brentwood Road, Ste. 107 Raleigh, North Carolina

FAX. (919) 873-9555PH. (919) 873-2211

1"=50'

LIF Boring and Soil Sample Locations

Veterans Terminal Investigation and Remediation Summary Report

Charleston County South Carolina

Charleston County South Carolina

N

0'

Approx. Scale in Feet

50' 100'

12/16/19

EN197343A.dwg

C. Vernoy

C. Vernoy

D. Malone

O. Sanchez

EN197343

APPENDIX A

PHOTOGRAPHIC LOG

Veterans Terminal Terracon Project No. EN197343 Date Photos Taken: July 31-August 9, 2019

Photo #1 View of excavation area near the northeaster corner.

Photo #2 View of excavation area near the northeastern corner.

Photo #3 View of tidal water mixing with contaminated soil.

Photo #4 View of pooled contaminated water being vacuumed.

Photo #5 View of excavaton area near the center portion looking towards the river.

Photo #6 View of stained soil along eastern edge of excavation.

Date Photos Taken: July 31-August 9, 2019

Photo #7 View of center of excavation area. Photo #8 View towards Pier Mike.

Photo #9 View of vacuuming contaminated water from excavation area.

Photo #10 View of unearthed partial pipe in center of excavation.

Photo #11 View of excavation area looking north.

Photo #12 View of excavation area looking southeast.

Date Photos Taken: July 31-August 9, 2019

Photo #13 View of excavation area looking southeast.

Photo #14 View of workers capping an unearthed cut pipe that was discovered during excavation.

Photo #15 View of excavation area. Photo #16 View of eastern excavation edge.

Photo #17 View of unearthed pipes that were capped. Pipes were discovered already cut/damaged when excavated.

Photo #18 View of eastern edge of excavation being shored up.

Date Photos Taken: July 31-August 9, 2019

Photo #19 View of excavating stained soil in the northern section of excavation.

Photo #20 View of sheen on water in northern section of excavation.

Photo #21 View of excavation area looking northwest.

Photo #22 View of vacuuming contaminated water from southern portion of excavation.

Photo #23 View of northern section of excavation.

Photo #24 View of center section of excavation.

Date Photos Taken: July 31-August 9, 2019

Photo #25 View of stained soil near southeastern corner of excavation.

Photo #26 View of excavation arear along eastern edge looking south.

Photo #27 View of capping unearthed pipe. Photo #28 View of capping unearthed pipe.

Photo #29 View of excavation area looking southeast.

Photo #30 View of equipment filling area with gravel.

Date Photos Taken: July 31-August 9, 2019

Photo #31 View of observation well in northern section of excavation area.

Photo #32 View of digging hole for observation well in southern area of excavation.

Photo #33 View of observation wells.

Veterans Terminal – LIF Investigation

Date Photos Taken: October 2019

Photo #1 View of Geoprobe and LIF/MIP van setting up at sample location.

Photo #2 View inside of LIF/MIP van.

Photo #3 View of Geoprobe setting up at a location on the eastern side of site.

Photo #4 View of open sample probe and sample jar.

APPENDIX B

FIELD NOTES

APPENDIX C

COLUMBIA TECHNOLOGIES HIGH-RESOLUTION SITE EVALUATION REPORT

Table 3 - LIF/UVOST Boring Locations Easting Northing

Station ID (feet) (feet) (feet msl)

L01 2,322,090.814 372,138.119 8.42 L02 2,322,113.316 372,160.177 7.21 L03 2,322,120.597 372,168.983 6.01 L04 2,322,110.863 372,189.986 6.07 L05 2,322,103.306 372,208.465 6.23 L06 2,322,095.137 372,226.573 6.50 L07 2,322,115.285 372,238.421 5.67 L08 2,322,106.196 372,256.520 5.46 L09 2,322,079.906 372,244.610 7.16 L10 2,322,059.743 372,234.218 7.48 L11 2,322,044.183 372,254.435 8.98 L12 2,322,078.519 372,260.241 7.71 L13 2,322,072.515 372,276.916 8.49 L14 2,322,043.261 372,224.228 8.13 L15 2,322,048.359 372,206.088 7.40 L16 2,322,026.324 372,198.588 8.95 L17 2,322,041.632 372,172.911 8.05 L18 2,322,102.089 372,267.757 5.31 L19 2,322,147.541 372,176.897 3.30 L20 2,322,137.875 372,251.748 3.19 L21 2,322,150.361 372,231.864 1.84 L22…