Greenville, SC Courthouse Project Phase II ESA report - PHE May 27, 2010.pdf

Phase II Environmental Site Assessment

Future Federal Courthouse Project

Leatherwood Site

E. North Street, E. Coffee Street, N. Spring Street & N. Irvine Street

Greenville, South Carolina

PHE Project #

U.S. General Services Administration

Potomac

1161 Broad Street, Suite 318, Shrewsbury, NJ 07702 Tel

REPORT

Environmental Site Assessment

Leatherwood Site

E. North Street, E. Coffee Street, N. Spring Street & N. Irvine Street

Greenville, South Carolina

PHE Project #1203-002

May 27, 2010

Prepared for:

Mr. Ashish Desai

U.S. General Services Administration

Southeast Sunbelt Region

77 Forsyth Street, Suite 450 Atlanta, GA 30303

Prepared by:

Potomac-Hudson Engineering, Inc.

1161 Broad Street, Suite 318, Shrewsbury, NJ 07702 Tel 732.578-9078 Fax 732.578.0192 www.phe.com

Environmental Site Assessment

E. North Street, E. Coffee Street, N. Spring Street & N. Irvine Street

PHASE II ENVIRONMENTAL SITE ASSESSMENT

FOR

FUTURE FEDERAL COURTHOUSE PROJECT

LEATHERWOOD SITE

E. NORTH STREET, E. COFFEE STREET, N. SPRING STREET, &

N. IRVINE STREET

GREENVILLE, SOUTH CAROLINA

“I declare that, to the best of my professional knowledge and belief, I meet the definition of Environmental

Professional as defined in § 312.10 of 40 CFR Part 312

Subpart B.”

“I have the specific qualifications based on education, training, and experience to assess a property of the nature, history, and setting of the subject property. I have developed and performed the all appropriate inquiries in conformance with the standards and practices set forth in

40 CFR Part 312.”

Thomas A. Varner

Principal

Potomac-Hudson Engineering, Inc.

Potomac-Hudson Engineering, Inc. i

TABLE OF CONTENTS

EXECUTIVE SUMMARY

1.0 INTRODUCTION

1.1 Purpose and Scope

1.2 Limitations and Exceptions of the ESA

2.0 METHODOLOGY AND APPROACH

2.1 Geophysical Survey

2.2 Soil and Groundwater Sampling

3.0 ANALYTICAL METHODOLOGY AND QUALITY

ASSURANCE/QUALITY CONTROL (QA/QC) PROCEDURES

4.0 DISCUSSION OF RESULTS

4.1 Geophysical Survey

4.2 Soil and Groundwater Sampling

4.2.1 Overview

4.2.2 General Site Lithology

4.2.3 Summary of Results by REC

4.2.3.1 REC-1: Former Gas Station

4.2.3.2 REC-2: Former Heating Oil UST at 202 E. North Street

4.2.3.3 REC-3, REC-4, and REC-5

4.2.3.4 REC-6: Site-wide Potential Historical Fill

4.2.3.5 REC-7: Site-wide Potential Undiscovered USTs

4.2.3.6 REC-8: Subsurface Anomaly on West Block

4.2.4 Abandonment Procedures

4.2.5 Investigation-Derived Wastes

5.0 CONCLUSIONS AND RECOMMENDATIONS

Phase II Environmental Site Assessment May 2010

Future Federal Courthouse Site Leatherwood Site, Greenville, SC ii

APPENDICES

APPENDIX A: Figures

APPENDIX B: Geophysical Survey Report

APPENDIX C: Sample Results Summary Tables and Complete Laboratory Reports

APPENDIX D: Water Well Records

APPENDIX E: Waste Disposal Documentation

TABLES

Title Page/Location

Table 1: Quality Assurance Summary Table

Table 2: Summary of Soil Boring Observations and Samples Collected

Table 3: Summary of Temporary Well Boring Observations and Samples Collected

Table 4A: Soil Sample Summary

Table 4B: Groundwater Sample Summary

Table 5A: Soil Sample Results - Detections ............................................................. Appendix C

Table 5B: Groundwater Sample Results - Detections .............................................. Appendix C

Table 6A: Complete Soil Sample Results .................................................................. Appendix C

Table 6B: Complete Groundwater Sample Results ................................................... Appendix C

FIGURES

Title Location

Figure 1: USGS Topographic Map ............................................................................ Appendix A

Figure 2: 2006 Aerial Photograph .............................................................................. Appendix A

Figure 3: Tax Map ..................................................................................................... Appendix A

Figure 4: Sample Results Map ................................................................................... Appendix A

EXECUTIVE SUMMARY

In March and April 2010, Potomac-Hudson Engineering, Inc. (PHE) conducted a Phase I

Environmental Site Assessment (ESA) on behalf of the U.S. General Services Administration

(GSA) for a multi-parcel site located in Greenville, South Carolina. The Phase I ESA was conducted in accordance with the current ASTM (E1527-05) and EPA (40 CFR Part 312) guidelines, which included interviews with key personnel, a review of historical documents, maps and aerial photographs, and a site inspection. The purpose of the Phase I ESA was to identify Recognized Environmental Conditions (RECs) at the site resulting from historical and/or current usage or condition of the property.

The subject site (a/k/a “Leatherwood site”) is the proposed location for a future federal courthouse. The site encompasses one entire city block and a portion of the adjacent city block to the east in downtown Greenville (approximately 2.5 acres total) and is bordered by N. Spring

Street, E. North Street, E. Coffee Street, and a Palmetto Bank facility. The majority of the site is a paved private parking lot; a small portion is occupied by a drive-through Wachovia Bank.

Based upon the results of the Phase I ESA, several RECs were identified for the subject property.

• REC-1: Former Gas Station – From the early 1930s until approximately 1970, a gasoline station occupied the northeast corner of the western block portion of the site.

Historical Sanborn maps indicate that this facility utilized at least two underground storage tanks (USTs). No records exist to indicate whether these tanks were ever properly closed and/or removed. The potential exists for additional USTs (e.g., waste oil) to exist or have existed on this parcel. In addition, the possibility for other features of concern, such as subsurface hydraulic lifts, also exists for this parcel.

• REC-2: Former Heating Oil UST at 202 E. North Street – According to the City of

Greenville Fire Chief, one 750-gallon UST was formerly located at 202 E. North Street, located at the northwest corner of the western block. The files indicated that the UST was removed in July 1996. No information was found regarding the condition of the tank, the presence of contamination, or the collection of any soil or groundwater samples.

• REC-3: Former UST at Wachovia Bank Parcel – The City of Greenville Fire Chief also was in possession of information which indicated that a 3,000-gallon UST may have formerly been located on the eastern block of the subject property. The records indicated that the UST was located at 304 E. North Street and was removed in November 1992 during construction of the First Union drive-thru bank (currently Wachovia). City directories confirmed that First Union was located at 304 E. North Street.

• REC-4: Former Fill Port Observed at Palmetto Bank Property – A UST fill port was observed by PHE personnel during a previous inspection of the site in 2005, which has since been removed based upon the site visit conducted in April 2010. The fill port was observed south of the Palmetto Bank building. It is unclear whether this tank represents

Phase II Environmental Site Assessment May 27, 2010

Potomac-Hudson Engineering, Inc. 2 the 3,000-gallon UST reportedly removed from the site (as described above), the 3,000-gallon UST associated with the Palmetto Bank and closed-in-place (described below), or is a different tank.

• REC-5: Palmetto Bank LUST Case – The Palmetto Bank, located at 306 E. North

Street immediately adjacent to the eastern portion of the site, was the location of a leaking UST. A 3,000-gallon diesel fuel tank was observed to be leaking at the Palmetto

Bank in March 1993. The tank was subsequently investigated and abandoned in place, and a letter of No Further Action (NFA) with respect to environmental investigation involving the UST, was issued by the South Carolina Department of Health and

Environmental Control (SCDHEC) in May 1993. Based upon surface topography, groundwater flow direction is expected to be towards the south across the site. The

Palmetto Bank would therefore be located sidegradient of the subject property. However, exact groundwater flow direction at the site is unknown at this time.

• REC-6: Site-wide Potential Historical Fill – A Phase I ESA and Subsurface

Exploration Report were prepared for the western block of the site in 1996 and 1998, respectively, by S&ME, Inc., a third-party consulting firm. The subsurface exploration consisted of nine soil borings drilled across the block to various depths ranging from 22 to 38 feet below ground. The report identified historical, non-native fill material in several of the borings at the site from the surface to depths of 3 to 6 feet below ground.

Fill material has the potential to be contaminated, depending on its origin.

• REC-7: Site-wide Potential Undiscovered USTs – The historical development of the site indicates the potential for additional heating oil or other USTs to exist or have previously existed at the subject property.

In order to address these RECs, PHE conducted a Phase II ESA at the subject property during the period April 18-22, 2010. The Phase II ESA consisted of a geophysical survey of the site as well as soil and groundwater sampling.

The geophysical survey was conducted on April 18, 2010, and consisted of a site-wide electromagnetic survey (EM) in conjunction with ground-penetrating radar (GPR). No USTs were observed during the geophysical survey. The GPR results for the former gas station UST area were consistent with a disturbed and/or backfilled area. One subsurface anomaly was detected near the center of the western block. Based upon size, depth, and shape, it is suspected that this anomaly represented a sump or similar feature. With the exception of various subsurface utilities, no other suspect features were observed.

As a result of the anomaly observed on the western block, PHE identified one additional REC for the purposes of this Phase II ESA:

• REC-8: Subsurface Anomaly on West Block

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A total of 45 borings were advanced at the site, ranging in depth from 5 feet to 80 feet below ground surface (bgs). The borings were installed using a combination of direct-push and air-rotary drilling methods. A total of six soil samples (plus one environmental duplicate) and three groundwater samples were collected for a wide suite of analyses as required by SCDHEC regulations and guidance.

Evidence of contamination was observed in borings located in the vicinity of the former gas station, which included strong odors and elevated photoionization detector (PID) readings. The extent of noticeably contaminated soil was of limited horizontal extent (approximately 750 square feet); horizontal delineation was qualitatively achieved through soil observations made at adjacent boreholes. The presence of bedrock and/or partially weathered rock (PWR) precluded vertical delineation in this area; however, one groundwater sample was collected at the location of the boring which displayed evidence of greatest contamination observed.

Possible historical fill material was also observed at the site and was sampled at two locations.

Soil contamination was found at the former gas station area (REC-1). The horizontal extent appears to be limited to approximately 750 square feet but the vertical extent is unknown. A petroleum constituent was detected in a groundwater sample from the former gas station area below regulatory screening criteria; however, all planned groundwater sampling could not be completed, and groundwater flow direction is uncertain due to the presence of a fractured bedrock aquifer system; therefore, it is possible that groundwater contamination remains undiscovered at the former gas station REC. Additional soil sampling is recommended to delineate the extent of vertical contamination, and groundwater sampling should be conducted to complete the original scope of work and adequately address the potential for contamination in this REC.

Evidence of soil contamination was not observed in borings advanced in the suspected areas of the former 750-gasllon heating oil UST (REC-2) and the former 3,000-gallon diesel UST

(Wachovia Bank property; REC-3); however, no information exists regarding the former location of these USTs. Groundwater samples were planned for these RECs, as well as along the property perimeter to address the potential presence of previously present/unknown USTs (REC-

7), which could not be completed due to time and budgetary constraints. This groundwater sampling should be conducted to complete the original scope of work and adequately address the potential for contamination in these RECs.

The Palmetto Bank fill port (REC-4) and the Palmetto Bank LUST (REC-5) are off-site and can be addressed via groundwater sampling on the Wachovia Bank property. No further action is warranted for historical fill (REC-6) or the west block subsurface anomaly (REC-8).

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1.0 INTRODUCTION

1.1 Purpose and Scope

Potomac-Hudson Engineering, Inc. (PHE), under contract to the U.S. General Services

Administration (GSA), conducted a Phase II Environmental Site Assessment (ESA) at a multi-parcel site located in Greenville, South Carolina.

The subject site (a/k/a “Leatherwood site”) for this Phase II ESA is the proposed location for a future federal courthouse. The site encompasses one entire city block and a portion of the adjacent city block to the east in downtown Greenville (approximately 2.5 acres) and is bordered by N. Spring Street, E. North Street, E. Coffee Street, and a Palmetto Bank facility. The majority of the site is a paved private parking lot; a small portion is occupied by a drive-through

Wachovia Bank. The location of the site can be found on the topographic map depicted in

Figure 1, a copy of a recent aerial photograph for the site as depicted in Figure 2, and a copy of the current tax map depicted in Figure 3. Figures 1 through 3 can be found in Appendix A.

The Phase II ESA consisted of a geophysical survey of the entire property as well as an intrusive subsurface investigation at the site for the purpose of collecting soil and groundwater samples.

The Phase II ESA was conducted solely to inspect for the presence or absence of contamination related to the seven RECs identified at the site during preparation of the Phase I ESA, as well as any additional concerns identified during the geophysical survey. Delineation of any observed contamination was not intended nor implied in the scope of work for this investigation.

Phase II ESA activities were conducted during the period April 18-22, 2010. A total of six soil samples and three groundwater samples were collected from a total of 44 borings investigated across the site to depths ranging from 5 feet to 80 feet below ground surface (bgs). Groundwater sampling was conducted via temporary well points installed and subsequently abandoned in the field (i.e., no monitoring wells were installed). Therefore, the groundwater sample analysis results only approximately represent actual conditions and are usable for screening purposes only.

1.2 Limitations and Exceptions of the Phase II ESA

This ESA was conducted with the following limitations and exceptions, some of which were established to define the scope of work and focus the assessment:

• Soil sampling at the site was conducted using a Geoprobe® direct-push unit. In general, refusal was encountered with the Geoprobe at depths ranging from 5 to 20 feet bgs primarily as a result of competent bedrock and/or partially-weathered rock (PWR).

Refusal precluded the inspection of soil cores below the depth of refusal, where additional unconsolidated material and/or contamination may have existed.

Potomac-Hudson Engineering, Inc. 5

• Groundwater flow direction is presumed to be towards the south or southwest at the site, based upon surface topography and the location of nearby surface water bodies (i.e., Reedy River). However, the exact direction of groundwater flow is not known at this time. In addition, two distinct groundwater regimes may exist at the site, consisting of shallow groundwater perched above the bedrock and an aquifer located within fractured bedrock. Time and budget constraints precluded the collection of a sufficient number of groundwater samples to properly characterize both types of groundwater occurrences and account for the potential variability of groundwater flow.

• The locations of certain UST RECs were determined based largely upon anecdotal information and historical maps. No site plans, as-built drawings, etc., were found to determine the precise locations of these features. Surface evidence of these features was largely precluded based upon the demolition of all historical buildings and the application of asphalt across the majority of the site. While the geophysical survey did not identify the locations of any current or former suspected tank areas at the site, the possibility exists that the actual location(s) of one or more RECs were located outside of the areas of the intrusive investigation.

• Due to time constraints and the need to use more expensive air rotary drilling methods due to bedrock, groundwater sampling was not conducted at all RECs as planned and the scope of work was not completed.

It should be noted that all statements, findings, and conclusions contained in this Phase II ESA are based upon: (i) site conditions at the time of the PHE reconnaissance and inspection; (ii) review of written or illustrated historical documents as available; and (iii) information reported to PHE by others. While there are no indications that the information provided is suspect, PHE does not assume responsibility for errors and omissions in the information assembled to produce this Phase II ESA.

This report has been prepared solely for the benefit of the U.S. General Services Administration and may not be relied upon by any other party without the written authorization of Potomac-

Hudson Engineering, Inc. Potomac-Hudson Engineering, Inc. assumes no responsibility or liability for unauthorized third-party use of this Phase II ESA.

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2.0 METHODOLOGY AND APPROACH

2.1 Geophysical Survey

On April 18, 2010, PHE conducted a geophysical survey at the subject property for the purposes of identifying subsurface utilities, anomalies, and other features which may represent an REC for the site. Reed-Tech, Inc. (Reed-Tech), of Columbia, South Carolina, was retained to perform the geophysical survey.

Initially, an electromagnetic (EM) survey was conducted across the entire site in transects at five-foot spacing oriented both north-south and east-west across the property. This was done in order to initially identify the location and general extent of any subsurface anomalies. A ground-penetrating radar (GPR) survey was subsequently conducted in order to further investigate and delineate any initial subsurface anomalies identified by EM. The GPR was also used at all previously identified suspected UST locations across the site whether or not the EM had identified an anomaly in order to provide further assurance that no feature(s) existed in these areas.

On April 20, 2010, personnel of Reed-Tech returned to the site to conduct additional screening for underground utilities in and around the areas of the site subject to the intrusive investigation.

This was conducted in order to supplement a utility mark-out which had been called in for the site on April 14, 2010, using the South Carolina One Call System (Palmetto Utility Protection

Service, or PUPS).

2.2 Soil and Groundwater Sampling

A total of 41 soil borings (B-1 through B-41) and three temporary well points (TW-1, TW-2, and

TW-3) were installed at the site during the period April 20-22, 2010. Landprobe Drilling

Services, LLC (Landprobe) was retained to conduct all drilling activities, temporary well installation, and boring abandonment procedures at the site.

All soil borings were advanced using a Geoprobe direct-push unit with five-foot-long, two-inch-diameter, stainless steel macrocores. Each macrocore was lined with an acetate sleeve to prevent cross-contamination. All borings were planned to be advanced to a depth of 12 feet bgs or to the water table (estimated to be approximately 25 feet bgs) depending on the REC being investigated, unless refusal was encountered at a shallower depth. Refusal was encountered at all soil borings prior to reaching the water table at depths ranging from 5 feet to 20 feet bgs.

Each soil core retrieved was field-screened with a properly calibrated MiniRae photoionization detector (PID) to inspect for the presence of volatile organic compound (VOC) vapors. In addition, evidence of stains, odors, and PID readings within the core were also noted for every location and recorded in a bound, project-dedicated logbook. All soil cores were also logged for percent recovery, grain size/texture, and color.

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Six soil samples were collected from these 41 borings based upon appearance, odor, elevated

PID readings, and other observations. For soil samples collected from petroleum UST RECs, laboratory analyses consisted of VOCs including methyl tert-butyl ether (MTBE), polycyclic aromatic hydrocarbons (PAHs) via low-level (SIMS) methodology which includes naphthalene, total petroleum hydrocarbons – diesel-range organics (TPH-DRO) using EPA Method 3550

(preparation method), and lead. For historic fill samples, laboratory analyses included VOCs, PAHs, EPA target analyte list (TAL) metals, TPH-DRO, pesticides, and polychlorinated biphenyls (PCBs). All soil sample analyses were chosen based upon the requirements of

SCDHEC.

Due to shallow refusal using Geoprobe® methods, it was determined that an air-rotary drill rig would be required to penetrate bedrock and PWR in order to install temporary well points at the site. A total of four well points were attempted at the site using air rotary methods, with groundwater samples collected from three of these locations. The air-drilled borings ranged in depth from 36 feet to 80 feet bgs.

All groundwater samples were collected from passively-placed, narrow diameter points consisting of ten feet of one-inch-diameter slotted PVC screen (0.10-inch) at the bottom of each well point and the remainder consisting of un-slotted PVC piping (riser) from the top of the well screen to the surface. Clean suitable sand was placed around the annulus of the wells up to and above the top of the well screen.

Depth-to-water measurements were made before purging and immediately following sampling.

The headspace in each well was also screened with the PID prior to purging and sampling.

Groundwater from each temporary well point was purged with polyethylene tubing attached to a check (foot) valve using the principle of inertia. Purging of groundwater was conducted at each well point by rapidly moving the tube up and down to retrieve groundwater. Approximately 3 to

5 well volumes were purged at each well point prior to sampling. Groundwater sample fractions for all analyses were also conducted using the check-valve tubing method. Groundwater samples were analyzed for low-level VOCs (including BTEX, MTBE, 1,2-dichloroethane, and ethylene dibromide), PAHs (SIMS) including naphthalene, and lead. All groundwater sample analyses were chosen based upon the requirements of SCDHEC.

All boring and temporary well locations were photographed and subsequently surveyed for horizontal location using a Trimble Pro XRS Global Positioning System (GPS) unit with sub-meter accuracy.

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3.0 ANALYTICAL METHODOLOGY AND QUALITY

ASSURANCE/QUALITY CONTROL (QA/QC) PROCEDURES

All soil and groundwater samples were submitted to Pace Analytical Services, Inc. (Pace), a

South Carolina-certified laboratory, under chain-of-custody procedures. All samples were delivered to Pace in laboratory-provided bottleware and coolers, and were preserved with ice.

A total of six primary soil samples and three groundwater samples were collected. In addition, one soil environmental duplicate sample and one soil trip blank (VOCs only) were also collected for QA/QC purposes. For soil samples collected from petroleum UST RECs, laboratory analyses consisted of VOCs including methyl tert-butyl ether (MTBE), PAHs (SIMS) including naphthalene, TPH-DRO using EPA Method 3550 (preparation method), and lead. For historical fill soil samples, laboratory analyses will include VOCs, PAHs (SIMS), TAL metals, TPH-DRO, pesticides, and polychlorinated biphenyls (PCBs).

Soil samples collected for VOCs analysis were transferred directly from the macrocores to the appropriate bottleware via laboratory-provided plastic plungers which allowed a pre-determined sample volume of 5 grams.

Groundwater samples were analyzed for low-level VOCs (including BTEX, MTBE, 1,2-dichloroethane, and ethylene dibromide), PAHs (SIMS) including naphthalene, and lead.

Groundwater fractions for VOCs analysis were filled with zero headspace to avoid VOC loss during shipping.

The table below provides a summary of analytical methods and QA/QC procedures. All analytical parameters and methodologies were performed in accordance with SCDHEC requirements.

Table 1. Quality Assurance Summary Table

Matrix No. of

Samples

No. of

Duplicates

No. of

Trip

Blanks

Analytical

Parameters

(Method)

No. of

MS/MSD

Container

Volume Preservative

HT to

Extraction

(days)

HT to

Analysis

(days)

Soil 6 1 1

VOCs, MTBE

(8260/5035E)

3 x 40mL clear, 1 x

40mL amber

MeOH (1), Na2S2O3 (2), Ice, 4°C

N/A 14

Soil 6 1 0

PAHs

(SIMS)

(8270)

1 1 x 4oz Ice, 4°C 14 40

Soil 6 1 0

TPH-DRO

(3550) 1 1 x 4oz Ice, 4°C 14 40

Soil 4 0 0 Lead

(6010 ICP)

1 1 x 4oz Ice, 4°C N/A 180

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Matrix No. of

Samples

No. of

Duplicates

No. of

Trip

Blanks

Analytical

Parameters

(Method)

No. of

MS/MSD

Container

Volume Preservative

HT to

Extraction

(days)

HT to

Analysis

(days)

Soil 2 1 0 TAL Metals

(200.7) 1 1 x 4oz Ice, 4°C N/A 180

Soil 2 1 0

TCL

Pesticides

(8081)

1 1 x 4oz Ice, 4°C 14 40

Soil 2 1 0 PCBs

(8082) 1 1 x 4oz Ice, 4°C 14 40

GW 3 0 0

VOCs, MTBE, EDB, 1,2-DCA

(8260)

1 3 x 40mL HCl, Ice, 4°C N/A 14

GW 3 0 0

PAHs

(SIMS)

(8270)

2 x 1L amber Ice, 4°C 7 40

GW 3 0 0

Lead

(6010 ICP)

1 x

250mL plastic

HNO3, Ice, 4°C N/A 180

MS/MSD = Matrix spike/matrix spike duplicate; HT = Holding time

Additional quality assurance/quality control (QA/QC) procedures included calibrating the gas chromatograph/mass spectrometer (GC/MS) each day prior to analysis, analyzing method blanks, spiked blanks, matrix spikes, and surrogates, as well as collecting environmental duplicate samples in the field. Surrogates are compounds not typically found in nature that are added in known quantities to all organic samples. The compounds added are similar to the compounds actually being sought in the analysis. A high surrogate recovery (usually 50% to 120%) indicates that the method was successful in analyzing the target compounds. Spiked blanks and matrix spikes are similar to surrogates in determining the accuracy of the analysis methodologies. Method blanks are used to determine if any contamination was added “by the method itself” during sample analysis.

Copies of QA/QC methodology, laboratory reports, chains-of-custody, and other documentation are located in Appendix C.

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4.0 DISCUSSION OF RESULTS

4.1 Geophysical Survey

The entire subject property was surveyed by personnel of Reed-Tech using EM technology, while GPR was used in a supplemental manner in select locations. No definitive evidence of current or former USTs was observed during the geophysical survey.

One subsurface anomaly was observed near the center of the western block. The footprint of feature was approximately 8 feet by 10 feet. According to Reed-Tech, the shape, depth, size, and signature of the anomaly indicated that it was likely sump or similar feature.

Generally disturbed soils were evident based upon GPR results in the area of the former gas station (REC-1), particularly in the area of the former USTs as indicated on historical Sanborn

Fire Insurance maps.

No other significant subsurface anomalies were identified during the geophysical survey. A copy of the Geophysical Evaluation letter report from Reed-Tech is included in Appendix B.

4.2 Soil and Groundwater Sampling

4.2.1 Overview

After completion of the Phase I ESA and geophysical survey at the subject property, PHE identified a total of eight RECs which were subsequently investigated during the Phase II ESA.

A total of 41 soil borings (B-1 through B-41) and three temporary well points (TW-1, TW-2, and

TW-3) were installed at the site during the period April 20-22, 2010. Seven soil samples

(including one environmental duplicate) and three groundwater samples were collected.

Table 2 below provides a summary of soil boring observations and sample depths for the 41 borings installed via Geoprobe at the site.

Table 2. Summary of Soil Boring Observations and Samples Collected

Boring

ID

Total

Depth

(bgs)

PID Readings

Observed

(bgs)

Max PID

(units) and

Depth (bgs)

Odors

Observed

Sample

ID

Sample

Depth (bgs)

B-1 13.5 ft None N/A None None N/A

B-2 17 ft None N/A None None N/A

B-3 18.5 ft None N/A None None N/A

B-4 9 ft 2.5 to 8.5 ft 64 (3 ft) Moderate gasoline B-4-1 2.5 to 3 ft

B-5 5 ft 0.5 to 5 ft 678 (4.5 ft) Strong gasoline B-5-1 4 to 4.5 ft

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Boring

ID

Total

Depth

(bgs)

PID Readings

Observed

(bgs)

Max PID

(units) and

Depth (bgs)

Odors

Observed

Sample

ID

Sample

Depth (bgs)

B-6 19 ft 0.5 to 1.5 ft 9.2 (1.5 ft) None None N/A

B-7 13 ft None N/A None None N/A

B-8 8 ft None N/A None None N/A

B-9 15 ft None N/A None None N/A

B-10 12.5 ft None N/A None None N/A

B-11 5 ft None N/A None None N/A

B-12 6 ft None N/A None None N/A

B-13 9 ft 8 to 8.5 ft 17.2 (8.25 ft)

Faint, unidentified

B-13-1 8 to 8.5 ft

B-14 19 ft 1.5 to 2 ft 0.5 (2 ft) None None N/A

B-15 11.5 ft None N/A None None N/A

B-16 11 ft None N/A None None N/A

B-17 18 ft 14-14.5 ft 3 (14.25 ft) None None N/A

B-18 14.5 ft None N/A None B-18-1 14 to 14.5 ft

B-19 10.5 ft None N/A None None N/A

B-20 9 ft None N/A None None N/A

B-21 9.5 ft None N/A None None N/A

B-22 13 ft None N/A None None N/A

B-23 19 ft None N/A None None N/A

B-24 8 ft None N/A None None N/A

B-25 6 ft None N/A None None N/A

B-26 14 ft None N/A None None N/A

B-27 17.5 ft None N/A None None N/A

B-28 17 ft None N/A None None N/A

B-29 14 ft None N/A None

B-29-1 0 to 1.25 ft

D-1 0 to 1.25 ft

B-29-2 10.25 to 11.25 ft

B-30 7 ft None N/A None None N/A

B-31 13 ft None N/A None None N/A

B-32 20 ft None N/A None None N/A

B-33 20 ft None N/A None None N/A

B-34 19 ft None N/A None None N/A

B-35 18.5 ft None N/A None None N/A

B-36 15 ft None N/A None None N/A

B-37 15 ft None N/A None None N/A

B-38 14 ft None N/A None None N/A

B-39 15 ft None N/A None None N/A

B-40 10 ft None N/A None None N/A

B-41 10 ft None N/A None None N/A PID - photoionization detector; ft = feet; N/A = not applicable; bgs = below ground surface

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Table 3 below provides a summary of observations, measurements, and sample depths for the four borings installed via air-rotary drilling at the site.

Table 3. Summary of Temporary Well Boring Observations and Samples Collected

Boring

ID

Total

Depth

(bgs)

Top of

Bedrock

(bgs)

Depth

Groundwater

Encountered

DTW at

Time of

Sample

Screened

Interval

Sample

ID

Purge Rate and

Volume

TW-1 79.5 ft 8 to 9 ft 74 ft 63.75 ft

69.5 to

79.5 ft

TW-1

450 mL/min;

3 gallons

TW-2 36 ft 35 ft 35 to 36 ft 27.2 ft 26 to 36 ft TW-2 400 mL/min;

1.5 gallons

TW-3 36 ft 22 ft 34 ft 27.5 ft 26 to 36 ft TW-3 400 mL/min;

2 gallons

TW-4 80 ft NR No water N/A N/A None N/A

DTW = depth to water; N/A = not applicable; NR = not recorded; bgs = below ground surface; mL = milliliters

Borings B-1 through B-29, as well as temporary wells TW-1 through TW-3, were all installed in

REC-1. Therefore, groundwater samples were not collected from any other RECs as planned.

Borings B-30 through B-33 were investigated to address REC-2; borings B-36 through B-39 were investigated to address REC-3, as well as REC-4 and REC-5 to a lesser extent. Borings B-

29, B-40, and B-41 were specifically installed to investigate REC-6, while all other borings were also used to evaluate the amount, extent, and location of historical fill in a supplemental manner.

Finally, borings B-34 and B-35 were investigated to address REC-8. No evidence of additional past or present USTs was observed via the geophysical survey of the site; therefore, REC-7 was not of concern and therefore was not investigated.

Tables 4A and 4B below provide an overview of the analyses performed on each soil and groundwater sample collected, respectively, as well as the REC from which the sample was collected.

Potomac-Hudson Engineering, Inc. 14

Table 4A: Soil Sample Summary

Analyses

Location Sample

ID

Sample

Interval

(bgs)

TCL

VOCs*

PAHs**

(SIMS)

TPH-

DRO

TCL

Pesticides PCBs

TAL

Metals

Lead

(only)

REC-1

B-4-1 2.5 to 3 ft ���� ���� ���� ����

B-5-1 4 to 4.5 ft ���� ���� ���� ����

B-13-1 8 to 8.5 ft ���� ���� ���� ����

B-18-1 14 to

14.5 ft

REC-1

REC-6

B-29-1 0 to

1.25 ft

D-1 0 to

1.25 ft

B-29-2

10.25 to

11.25 ft

*Includes MTBE; **Includes naphthalene; bgs = below ground surface

Table 4B: Groundwater Sample Summary

Analyses

Location Sample

ID

Sample

Interval (bgs)

TCL VOCs

(low level)

MTBE, 1,2-DCA,

EDB (low level)

PAHs*

(SIMS)

Lead

REC-1

TW-1 69.5 to 79.5 ft ���� ���� ���� ����

TW-2 27.2 to 36 ft ���� ���� ���� ����

TW-3 27.5 to 36 ft ���� ���� ���� ����

*Includes naphthalene; bgs = below ground surface

4.2.2 General Site Lithology

During the preparation of the Phase I ESA report for this site, PHE was provided with a copy of a report entitled Subsurface Exploration, Downtown Block Office Building and Parking Deck, East North Street at North Spring Street, prepared for Highwoods Forsythe L.R. c/o Highwoods

Properties, prepared by S&ME, Inc. (S&ME), dated June 1998.

The S&ME investigation consisted of the installation of nine soil borings (B-1 through B-9) across the western block of the subject property via hollow stem rotary drilling methods. The boreholes were investigated from the surface to bedrock, which ranges in depth at the site from

Potomac-Hudson Engineering, Inc. 15

22 to 38 feet below ground surface (bgs). Shallow groundwater was encountered in six of the boreholes investigated. Where observed, the groundwater table was located at depths ranging from approximately 20 to 25 feet bgs.

In general, the lithology described by S&ME consisted of sandy silty clay or sandy clayey silt in the uppermost five to 10 feet, followed by alternating and varying amounts of medium to coarse sand and/or partially weathered bedrock to depths of 15 to 30 feet bgs, below which was competent bedrock consisting primarily of granite and biotite gneiss. The report also indicated the presence of historical fill material in certain areas of the site, located near the surface to depths ranging from 3 to 6 feet bgs.

During the Phase II ESA conducted by PHE, soil was logged from all soil borings installed by

Geoprobe methods, which ranged from the surface to depths of 5 to 20 feet bgs. In general, observations made by PHE are consistent with those by S&ME. The soil lithololgy at the site based on PHE observations is as follows:

• 0 to 5-8 feet: clay and sandy clay

• 5-8 to 20 feet: sand

• 8 to 32 feet: bedrock (with partially weathered rock above it)

4.2.3 Summary of Results by REC

The following sections include a summary of fieldwork, observations, and results for each REC investigated at the site. Please refer to Tables 4A and 4B for all sample analytical parameters.

All soil boring/sample locations and results summaries can be found on Figure 4 in Appendix A.

Copies of all laboratory data, including “detections only” tables, complete results summary tables, and complete laboratory reports, can be found in Appendix C.

Analytical results were compared to the SCDHEC Risk-Based Screening Levels (RBSLs). For those compounds which do not have a corresponding RBSL, the concentrations were compared to their respective U.S. Environmental Protection Agency (EPA) Region IX Regional Screening

Levels (RSLs). These guidelines were provided to PHE by personnel of SCDHEC.

4.2.3.1 REC-1: Former Gas Station

Soil

A total of 29 soil borings were investigated in this REC via Geoprobe

, from the surface to depths ranging from 5 feet to 20 feet bgs. All borings were advanced until refusal was encountered. Prior to the soil boring investigation, PHE personnel marked the ground surface in this REC to indicate the boundaries of the former buildings, pump dispenser area, and USTs as was provided on or inferred from historical Sanborn maps and aerial photographs. The soil borings were then installed in a grid-like pattern across all areas of the former gas station. As stated earlier, each five-foot macrocore of soil was field screened with a PID and logged for soil texture, percent recovery, and other observations such as stains, odors, and moisture.

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PID readings ranging from 10.4 to 64 units were observed from a depth range of 2.5 to 8.5 feet bgs at boring B-4. A moderate petroleum (weathered gasoline) odor was also observed throughout this interval. One soil sample (B-4-1) was collected from a depth of 2.5 to 3 feet bgs, which corresponded to the highest observed PID reading. This boring was terminated at 9 feet bgs as a result of refusal. Boring B-5, located approximately 14 feet east of B-4, contained strong petroleum odors throughout the entire interval, from near the surface to its maximum depth of 5 feet bgs (refusal). PID readings ranging from 2 to 678 units were observed from 0.5 to 5 feet bgs; sample B-5-1 was collected from a depth of 4 to 4.5 feet bgs, which corresponded to the highest observed PID readings.

Sample B-5-1 contained concentrations of naphthalene (0.579 milligrams/kilograms, or mg/kg), 1-methylnapthalene (0.066 mg/kg), and 2-methylnaphthalene (0.150 mg/kg), each of which individually exceeded the SCDHEC Risk-Based Screening Level (RBSL) level of 0.036 mg/kg for total naphthalenes. Naphthalenes are components of petroleum distillates, including gasoline and fuel oil. In addition, sample B-5-1 also contained concentrations of other petroleum constituents, including ethylbenzene, xylenes, isopropyltouene, propylbenzene, trimethylbenzenes, phenanthrene, and TPH, as well as lead. Sample B-4-1 also contained a concentration of naphthalene (0.14 mg/kg) which exceeded its SCDHEC RBSL. This sample also contained detectable concentrations of TPH, lead, and numerous PAH compounds.

Although the concentrations of these contaminants were below their respective RBSL or RSL

(where applicable), their presence indicates a historical release of petroleum within this REC.

A second boring was attempted approximately two feet west of B-5 in an attempt to achieve a greater depth. Refusal was also encountered at a depth of 5 feet bgs. Very strong petroleum odors and PID readings in excess of 2,000 units were observed at this location throughout the entire interval. Based on these observations, this borehole chosen as the location of a temporary well point and groundwater sample (discussed below).

Borings B-4 and B-5 were completely surrounded in all directions by additional borings B-3, B-

6, and B-11 through B-16, which covered an area of approximately 750 square feet. With the exception of relatively low PID readings (borings B-6, B-13, and B-14) and a small interval of a faint unidentifiable odor (B-13), these surrounding borings appeared to be relatively uncontaminated based on field observations and may have served to horizontally delineate the obvious contamination observed in borings B-4 and B-5. One soil sample (B-13-1) was also collected at B-13 at a depth of 8 to 8.5 feet bgs, at the location of PID readings and the faint unidentified odor. Sample B-13-1 contained relatively low concentrations of lead, ethylbenzene, xylenes, naphthalenes, trimethylbenzenes, isopropyltoluene, and phenanthrene, all of which are potentially associated with petroleum distillates; these concentrations were all below their respective RBSLs or RSLs, where applicable.

With the exception of a very low PID reading within boring B-17, no PID readings, stains, or odors were observed in the remaining borings in REC-1 (B-1, B-2, and B-18 through B-29).

One soil sample was collected at B-18 at a depth of 14 to 14.5 feet bgs to confirm the absence of contamination. This sample contained a low concentration of lead (10.2 mg/kg); all other results

Potomac-Hudson Engineering, Inc. 17 were non-detect for this sample. While lead was a component of leaded gasoline used historically, it is also a naturally-occurring metal which may be native to the soil in this area.

Two historical fill samples (and one environmental duplicate sample) were collected from boring

B-29; these results are discussed later under REC-6.

No soil moisture or other evidence of the apparent groundwater table was observed in the soil borings investigated in REC-1.

Groundwater

Three temporary well points (TW-1, TW-2, and TW-3) were installed via air rotary drilling methods and subsequently sampled within REC-1. A fourth well point (TW-4) was attempted at the south side of the western block. This boring was drilled to a depth of 80 feet bgs; however, no groundwater was encountered at the time of the boring installation.

TW-1 was installed adjacent to boring B-5, at the location of the highest observed PID readings in this REC. Competent bedrock was observed at this location at a depth of 8 to 9 feet bgs. The boring at this location was temporarily paused at depths of 30, 42, and 62 feet bgs to inspect for the presence of groundwater; none was observed. At a depth of approximately 74 feet bgs, a void in the bedrock was encountered, extending down to a depth of 78.5 feet bgs. Groundwater was observed within this void, and the boring was terminated at an approximate depth of 80 feet bgs. A temporary well was then constructed at this location, which contained 10 feet of 0.10-inch slotted PVC screen at the bottom of the borehole. Clean sand was placed in the annulus between the well screen and surrounding soil, from the bottom of the borehole to just above the top of the well screen. The well point was then allowed to sit and was monitored over the next hour.

Initial depth-to-groundwater at TW-1 was 71.9 feet bgs. Groundwater depth was then checked periodically over the next hour, and a rise of approximately 0.13 feet/minute was observed during that time. The rise in water level indicates that the groundwater at this location is confined (under pressure) within bedrock voids and fractures (artesian aquifer).

Depth-to-water immediately prior to purging was 63.25 feet bgs. The well was purged for approximately 20 minutes prior to sampling using tubing with a check-valve; approximately 3 gallons of water was purged. Sample TW-1 was subsequently collected with the check-valve tubing for VOC and PAH analyses. Sample TW-1 contained detectable concentrations of chloroform (1.1 micrograms/liter, or ug/L), lead (7.3 ug/L), and fluoranthene (0.2 ug/L). The concentration of lead was below its RBSL of 15 ug/L, and the concentration of fluoranthene was below its RSBL of 25 ug/L. No applicable corresponding RBSL or RSL was identified for chloroform. Chloroform was also observed in the other two groundwater samples collected at the site (discussed below), at similar concentrations, indicating that it may be related to laboratory contamination.

Two additional temporary wells were installed to the southwest (TW-2) and south (TW-3) of the former gas station area (including borings B-4 and B-5). At both locations, the borings were

Potomac-Hudson Engineering, Inc. 18 terminated at a depth of 36 feet bgs shortly after shallow groundwater was encountered. It is unknown whether the groundwater encountered at these locations is representative of the same aquifer as observed at TW-1, or if it represents a separate, shallow aquifer perched above the underlying bedrock.

Static water level immediately prior to purging was 27.2 feet bgs at TW-2 and 27.5 feet bgs at

TW-3. Both well points were constructed with 10 feet of 0.10-inch slotted PVC placed at the bottom of the borehole and filled with clean sand around the annulus. Purging and sampling was conducted using check-valve tubing; approximately 1.5 gallons of water was purged at TW-2 and approximately 2 gallons was purged at TW-3.

Sample TW-3, which was highly turbid, contained a concentration of lead (163 ug/L) which exceeded its RBSL of 15 ug/L. Sample TW-2 also contained lead, but at a concentration (9.5 ug/L) below its RBSL. TW-2 also contained a concentration of fluoranthene (0.02 ug/L) below its RSBL of 25 ug/L. Both samples also contained low concentrations of chloroform as discussed above.

It should be noted that these samples were collected from temporary wells and are considered

“screening” samples and may be biased high for lead, due to sample turbidity. In addition, the well points were installed using air-rotary drilling methods and may be biased low for VOCs due to agitation of the subsurface by compressed air. Permanent monitoring well installation is required to collect “compliance point” samples.

4.2.3.2 REC-2: Former Heating Oil UST at 202 E. North Street

Four soil borings (B-30 through B-33) were installed adjacent to the sidewalk along N. Spring

Street in the northwest corner of the western block. This area was the location of a former apartment building and office building located at 202 E. North Street. This building reportedly utilized a 750-gallon heating oil UST (exact location unknown).

The borings were located in a north-south line in the area of the former building footprint.

Refusal was encountered at a depth of 7 feet bgs at B-30, a depth of 13 feet bgs at B-31, and a depth of 20 feet bgs at both B-32 and B-33. No PID readings, stains, odors, or other evidence of contamination were observed in any of the soil cores retrieved from these boreholes. No samples were collected from this REC.

4.2.3.3 REC-3: Former UST at Wachovia Bank Parcel, REC-4: Former Fill Port Observed at

Palmetto Bank Property, and REC-5: Palmetto Bank LUST Case

Four soil borings (B-36 through B-39) were installed to investigate a former UST reportedly located on the eastern block portion of the site. The borings were located in a square pattern within the drive-through lanes of the Wachovia Bank, south of the building, in an area suspected to be the location of a former UST. The approximate location of the UST was determined based upon information obtained during the Phase I ESA.

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Refusal was encountered at a depth of 14 feet bgs at B-38; borings B-36, B-37, and B-39 encountered refusal at 15 feet bgs. No PID readings, stains, odors, or other evidence of contamination were observed in any of the soil cores retrieved from these boreholes. No samples were collected from this REC.

During the Phase II ESA it was determined that the location of the former fill port, and presumed leaking UST at the Palmetto Bank, were both located off-site of the subject property and therefore were not investigated as part of this Phase II ESA.

4.2.3.4 REC-6: Site-wide Potential Historical Fill

As mentioned earlier, the S&ME Subsurface Exploration report indicated the presence of historical fill material across portions of the site, ranging in depth from 3 to 6 feet bgs.

Borings B-40 and B-41, located on the south side of the western block, were installed in

“background” locations outside of any other known REC to inspect for the presence of fill material. Although these two borings were specifically installed to investigate for fill material, PHE inspected for and recorded the presence of fill material (where applicable) in all 41 soil borings installed at the site.

The historical development and disturbance of the site combined with the wide-varying nature of the native soil types observed onsite made it somewhat difficult to determine historical fill material from the native material. In general, two distinct shallow soil horizons were observed which may have been the result of historical fill material. These include a shallow, reddish-brown clayey layer and a slightly deeper, multicolored sandy layer.

Two samples were collected from possible fill material as described above at boring B-29.

Sample B-29-1 was collected from the reddish-brown clay from just below the surface to a depth of 1.25 feet bgs. An environmental duplicate sample (D-1) was also collected from this boring at this depth. Sample B-29-2 was collected from white, tan, brown, and dark grey sand in boring

B-29 at a depth of 10.25 to 11.25 bgs.

All three samples B-29-1, D-1, and B-29-2 contained concentrations of arsenic (2.9 mg/kg, 3.0 mg/kg, and 0.94 mg/kg, respectively) which exceeded its RSL of 0.39 mg/kg. Likewise, these three samples contained chromium concentrations (20 mg/kg, 20.6 mg/kg, and 14.2 mg/kg, respectively) which exceeded its RSL of 0.29 mg/kg. Elevated concentrations of metals are common to historical fill, but may also be naturally-occurring components of native soil.

In addition to the above, sample B-29-1 (0.021 mg/kg) and its duplicate sample D-1 (0.035 mg/kg) contained concentrations of benzo[a]pyrene (a PAH) which exceeded its RBSL of 0.015 mg/kg. Sample D-1 also contained a concentration of benzo[b]fluoranthene of 0.070 mg/kg which exceeded its RBSL of 0.066 mg/kg. Sample D-1 contained a concentration of one PCB congener (Arochlor-1260) of 0.055 mg/kg. This concentration was less than its respective RSL of 0.220 mg/kg, but provides further evidence of suspect fill material at the site.

Potomac-Hudson Engineering, Inc. 20

Numerous other PAH compounds and metals were detected in these samples, but at concentrations below their respective RBSL or RSLs.

4.2.3.5 REC-7: Site-wide Potential Undiscovered USTs

No evidence of additional past or present USTs was observed during the geophysical survey.

However, it is possible that former UST areas remain undiscovered. However, due to time and budgetary constraints, no groundwater sampling was conducted along the site perimeter to…