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Home My WebLink About21011_South Blvd Carvana_LSA Final Rpt_20170127 5113 Yachtsman Court Raleigh, North Carolina 27615 919-630-0721 January 27, 2017 Mr. Tim Tassopoulos, Manager NC CCT Holdings, LLC 1611 Nancy Creek Ridge Atlanta, Georgia 30327 Reference: LIMITED GROUNDWATER ASSESSMENT ACTIVITIES PROPOSED CARVANA SITE 3621 SOUTH BOULEVARD CHARLOTTE, MECKLENBURG COUNTY, NORTH CAROLINA PES PROJECT R17-192 Dear Mr. Tassopoulos: Proctor Environmental Services, Inc. (PES) has prepared this Limited Groundwater Site Assessment Report for the above referenced site. Our services were provided in accordance with proposal P17R-254a authorized by you on January 19, 2017. A site location map and a site map showing the area investigated are attached as Figures 1 and 2. The objective of our scope of services was to further evaluate the groundwater across the site to determine, if possible, the degree and extent of the adversely-impacted groundwater as well as the direction of groundwater flow under the site. BACKGROUND The subject site, approximately 1.96 acres of vacant land, is located at 3621 South Boulevard in Charlotte. ECS Carolinas, LLP completed a Phase I Environmental Site Assessment dated September 28, 2016 that identified an off-site recognized environmental condition (REC) in connection with the property. Based upon their findings, they recommended and implemented limited soil and groundwater assessment activities to evaluate the shallow soil and groundwater along the southwestern property border of the site on November 17, 2016. Two borings (TW-1 and TW-2), located as shown on Figure 2, were advanced and sampled and ultimately converted into shallow groundwater monitoring wells. As summarized in Table 1, groundwater samples collected from the wells exhibited petroleum-related volatile organic compounds (VOCs) at concentrations above the laboratory reporting limits. Two of the VOCs, 1,2‐ dichloroethane (1,2‐DCA) and methyl‐tert‐butyl‐ether (MTBE), were detected at concentrations above the respective North Carolina 2L Groundwater Quality Standards (NC2LGWQS). In addition, the chlorinated solvent tetrachloroethene, or PCE, was detected at a concentration below its NC@LGWQS. PCE is typically associated with dry-cleaning operations. Limited Groundwater Assessment Activities January 27, 2017 3621 South Boulevard Page 2 Charlotte, North Carolina PES GROUNDWATER ASSESSMENT ACTIVITIES Monitoring Well Installation and Sampling On January 21, 2017, seven (7) additional borings (TMW-3 through TMW-9) were advanced around the site for constructing temporary monitoring wells. The borings, located as shown on Figure 2, were advanced by hydraulically driving a five‐foot long, 1.5‐inch diameter soil sampling probe into the soil. Prior to advancing each boring, the down hole equipment and Geoprobe® drill rig were decontaminated utilizing a high pressure steam cleaner and municipal water to prevent cross‐contamination between boring locations. The temporary monitoring wells were constructed with one‐inch inside diameter Schedule 40 PVC flush‐threaded casing and screen. A ten‐foot length of slotted well screen with machined 0.010‐inch slot widths and a threaded bottom plug was installed at the bottom of each well. Drilling refusal was encountered at depths of approximately 20 to 24 feet below the ground surface (ft bgs) around the site. As such, the well screens were installed at the bottom of each boring. A solid section of PVC casing was placed above the screened interval and extended to just above the ground surface. The annular space around each well screen was filled with washed and graded medium sand to approximately two feet above the top of the screen. Well construction details are summarized in Table 2. The groundwater samples were collected using disposable polyethylene bailers, using a new bailer at each temporary well location. A minimum of three well volumes was purged prior to the collection of the groundwater samples. Following purging of the wells, groundwater samples were collected in laboratory‐prepared containers while wearing a new pair of disposable nitrile gloves at each sampling location. The groundwater sample containers were placed into protective packaging material and placed into an ice-filled cooler. The samples were submitted under proper chain-of-custody procedures to Prism Laboratories in Charlotte (Laboratory Certification #402) for chemical analysis for volatile organic compounds (VOCs) using EPA Method 8260. A copy of the laboratory analytical report is contained in the Appendix. The laboratory analytical results are summarized in Table 1 and discussed below. Static Water Level Measurement Activities Following installation, the horizontal location of each well was referenced to an existing, fixed landmark on the subject property and the top of casing elevation at each well was surveyed. On January 24, 2017, after allowing approximately 48 hours for the water table to stabilize after installation of the wells, the depth to liquid in each well was measured using an electronic water-interface probe. The interface probe was decontaminated between each well using an Alconox wash followed by a clean water rinse. The depth to groundwater beneath the property ranged from approximately 4 to 6 feet. Free-product petroleum was not detected on the groundwater surface in any of the groundwater monitoring wells. Liquid level data are summarized in Table 2. Based on survey and depth to groundwater data collected on January 24, 2017 and as shown in Figure 3, the direction of groundwater flow Limited Groundwater Assessment Activities January 27, 2017 3621 South Boulevard Page 3 Charlotte, North Carolina beneath the area of the subject property proposed for development is generally towards the east/southeast. Groundwater at the southern and northern property boundaries is migrating towards the northeast and southeast, respectively. This estimated flow direction is consistent with the area’s general topography, which is influenced by the drainage feature visible on the site’s eastern half, in the wooded area. SUMMARY OF FINDINGS AND OPINIONS Based upon our limited assessment activities, and in conjunction with the ECS Phase I, limited assessment and geotechnical reports, we find that: • Shallow groundwater flow beneath the area of the subject property proposed for development is towards the east/southeast; • Monitoring well TMW-3 was installed between former ECS wells TW-1 and TW-2 to confirm their findings. The only constituent detected in the sample from TMW-3 was MTBE (a gasoline octane enhancer), but at a much lower concentration (1.4 ug/L) than ECS reported from their two nearby wells; • The samples collected from the two of the five temporary wells located on the portion of the site to be developed (TMW-4 through TMW-8) also exhibited low concentrations (0.56 and 0.98 ug/L) of MTBE but all below its NC2LGWQS of 20 ug/L. The acetone detected in several of the samples from these wells is well below its standard of 6,000 ug/L and most likely a laboratory artifact; and • Monitoring well TMW-9 was installed approximately 150 east of the portion of the site to be developed, near the eastern property boundary and close to the jurisdictional wetlands there. Three constituents (1,2-DCA, MTBE, and PCE) were detected at concentrations in excess of their NC2LGWQS and similar to those in the ECS wells. It’s feasible that the PCE, a common dry-cleaning solvent, originated from the nearby “Duds n Suds” a former dry-cleaners located in the shopping center adjacent to the north of the site. However, we have no information that any assessment has been conducted at the Duds n Suds site. Based upon these findings, it is our opinion that: • The on-site contamination originates from one or more off-site sources, possibly the roadway, the railroad and/or other nearby historical sites. We cannot point to a specific release site, with the possible exception of the Duds N Suds, as mentioned above; • These low constituent concentrations should not prohibit the planned use of the site as none of them exceed (on the portion of the site to be developed) their NC2LGWQS or their vapor intrusion levels, also shown in Table 1; Limited Groundwater Assessment Activities January 27, 2017 3621 South Boulevard Page 4 Charlotte, North Carolina • It is our opinion that the site could be a good candidate for the NC Brownfields program if liability protection is a concern for either the property owner or the leasing party; and • These data should be reported to the state, in accordance with applicable regulations, with a statement that the site does not appear to be the source of the contaminants. CLOSING PES appreciates the opportunity to provide our services. If we can answer any questions or provide additional services, please feel free to contact us at your convenience. Sincerely, PROCTOR ENVIRONMENTAL SERVICES, INC. Thomas A. Proctor, P.G., RSM Senior Environmental Geologist Attachments: Figures, Tables, and Appendix FIGURES Figure 1 – Site Location Map Source: USGS 7.5 Minute Topographic Map, Charlotte West and Charlotte East Quadrangles, 2016 Scale: 1:24,000 PROPOSED CARVANA SITE 3621 SOUTH BOULEVARD CHARLOTTE, NORTH CAROLINA PES PROJECT NUMBER: R17-192 Figure 2 – Boring Location Map Source: ECS Report of Subsurface Exploration dated October 17, 2016 and PES Field Work Scale: 1’ = 130’ Proposed Carvana Site 3621 South Boulevard Charlotte, North Carolina PES Project Number: R17-192 TMW-3 TMW-4 TMW-5 TMW-6 TMW-7 TMW-8 LEGEND: ECS Sample Location (11/17/16) PES Sample Location (1/22/17) ECS Geotechnical Boring Location TW-1 TW-2 MW-9 (Approx 100 feet) Figure 3 – Groundwater Flow Direction Map Source: ECS Report of Subsurface Exploration dated October 17, 2016 and PES Field Work Scale: 1’ = 130’ Proposed Carvana Site 3621 South Boulevard Charlotte, North Carolina PES Project Number: R17-192 TMW-3 TMW-4 TMW-5 TMW-6 TMW-7 TMW-8 LEGEND: ECS Sample Location (11/17/16) (94.17’) Groundwater Elevation PES Sample Location (1/22/17) Estimated Flow Direction ECS Geotechnical Boring Location TW-1 TW-2 MW-9 (Approx. 150 feet) (92.00’) (92.23’) (95.69’) 91.96’ (94.17’) (93.40’) 92.00’ 94.00’ TABLES VOCs by Method 8260B (ug/L) Acetone 6,000 6,000,000 4,520,000 19,000,000 BRL 0.6 BRL BRL 7.5 5.2 16 14 BRL Chloroform 70 70,000 8.14 35.5 BRL BRL BRL BRL BRL BRL BRL BRL 1.5 1,2-Dichloroethane 0.4 400 22.4 97.8 2.2 7.7 BRL BRL BRL BRL BRL BRL 0.69 Isopropyl Ether (IPE)70 70,000 1,390 5,860 ND ND BRL BRL BRL BRL BRL BRL BRL Methyl-tert-butyl-ether (MTBE)20 400,000 4,500 19,700 52 76 1.4 0.56 BRL 0.98 BRL BRL 140 Tetrachloroethylene 0.7 700 11.5 48.4 BRL 0.59 BRL BRL BRL BRL BRL BRL 2.7 NOTES: Wells TW-1 and TW-2 were installed and sampled by ECS Carolinas, LLP µg/L - micrograms per liter (ppb) BRL - Below Laboratory Reporting Limit J - Detected but below the Reporting Limit Comparison Criteria: NC 2L Standard - North Carolina DEQ Groundwater Quality Standard NCGCL - NCDEQ Gross Contaminant Level Residential VISL - NCDEQ Residential Vaport Intrusion Screening Levels Non-Residential VISL - NCDEQ Residential Vaport Intrusion Screening Levels Bolded and Shaded concentrations denote NCAC 2L groundwater standard exceedance. Table 1Groundwater Analytical Results3621 South Boulevard Site TW-1Constituent Monitoring Well ID #, Sample Date and Constituent Concentration (ug/L) Charlotte, North Carolina TMW-9TMW-4 TMW-5 TMW-6 TMW-7 TMW-8 NC 2L Standard (ug/L)TMW-3 January 21 and 22, 2017 NCGCL (ug/L) NC Residential VISL (ug/L)TW-2 11/17/16 NC Non-Residential VISL (ugL) Well Well Type TMW-3 Type II TMW-4 Type II TMW-5 Type II TMW-6 Type II TMW-7 Type II TMW-8 Type II NOTES: All depths recorded in feet below TOC (Top of Casing). Depths to groundwater were measured on January 25, 2017. Table 2 Monitoring Well Construction Details and Static Water Level Elevations 3621 South Boulevard Date Installed TOC Elevation (ft) Depth to Groundwater Groundwater Elevation Well Diameter Screened Interval (ft) Total Depth 1 (ft) Charlotte, North Carolina 13' - 23'23 2001/21/17 98.63 5.23 93.40 1.5"10' - 20' 01/21/17 96.48 4.48 92.00 1.5" 2001/21/17 99.70 5.53 94.17 1.5"10' - 20' 01/21/17 98.24 6.28 91.96 1.5"10' - 20'20 01/21/17 01/21/17 97.81 99.73 5.58 4.04 92.23 95.69 1.5" 1.5" 14' - 24' 13' - 23' 24 23 APPENDIX LABORATORY ANALYTICAL RESULTS Page 1 of 24 Page 2 of 24 Page 3 of 24 Page 4 of 24 Page 5 of 24 Page 6 of 24 Page 7 of 24 Page 8 of 24 Page 9 of 24 Page 10 of 24 Page 11 of 24 Page 12 of 24 Page 13 of 24 Page 14 of 24 Page 15 of 24 Page 16 of 24 Page 17 of 24 Page 18 of 24 Page 19 of 24 Page 20 of 24 Page 21 of 24 Page 22 of 24 Page 23 of 24 Page 24 of 24