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Home My WebLink AboutWS-4084_13568_CA_MRP_20150127TABLE OF CONTENTS 1. BACKGROUND INFORMATION............................................................................................1 2. FIELD ACTIVITIES ..................................................................................................................1 3. LABORATORY RESULTS.......................................................................................................2 4. CONCLUSIONS.........................................................................................................................2 5. RECOMMENDATIONS............................................................................................................3 6. QUALIFICATIONS OF REPORT.............................................................................................3 FIGURES Figure 1 -- Topographic Site Map Figure 2 -- Site Plan Figure 3 -- Potentiometric Surface Map Figure 4 -- Groundwater Analytical Results Map TABLES Table B-4 -- Summary of Groundwater Analytical Results Table B-7 -- Monitoring Well Construction Information APPENDIX Laboratory Data Sheets and Chain-of-Custody Record Former Spray Exxon – Active Remediation Monitoring Report Eden, Rockingham County, North Carolina Progress Project No. 1015007.001 January 23, 2015 1 1. BACKGROUND INFORMATION The site is the former Spray Exxon located at 103 Boone Road in Eden, Rockingham County, North Carolina (Figure 1). The site consists of an active automotive maintenance shop, which stores gasoline and diesel fuel for retail sale in four underground storage tanks (USTs). The site is depicted on Figure 2. A 4,000-gallon diesel UST was removed by G & H Oil Equipment, Inc. of Greensboro, North Carolina in July 1990. The diesel UST was replaced with the existing 3,000-gallon diesel UST. Legacy Environmental Services, Inc. (Legacy) submitted an UST Closure Report in December 1998 describing the closure activities that occurred in 1990 as well as additional activities which occurred in 1998. Apex Environmental, Inc. previously completed a Corrective Action Plan, dated October 15, 2003 with respect to the release. Although the incident documented at the site is related to the removal of a diesel fuel UST, historically groundwater contamination beneath the site reflects a release of gasoline. Therefore, Progress collected groundwater samples for analysis for gasoline related compounds. It is Progress’ understanding that there is also a documented petroleum UST release at 102 Boone Road located northeast of, and contiguous to, the subject site. Progress was directed by the NCDENR to sample the eight existing site monitoring wells. A summary of the field activities, the results obtained and our conclusions and recommendations are detailed below. 2. FIELD ACTIVITIES Monitoring Well Sampling On December 17, 2014, Progress sampled site monitoring wells MW-1, MW-2, MW-3, MW-4, MW-5, MW-7, and MW-1D (Figure 2). Note that monitoring well MW-6 contained approximately 0.03 feet of free product and, therefore, was not sampled. Prior to sampling, a static water level measurement was collected to determine existing well volume. The water meter was decontaminated before use by washing in a solution of Alconox detergent and municipal water followed by a rinse with municipal water. The monitoring wells were then purged by evacuating at least three well volumes or until dry using a new disposable bailer dedicated to each well. Following purging, a groundwater sample was collected from each well using the disposable bailer dedicated to each well. Care was taken to minimize volatilization of the samples during the sampling process. Immediately after collection, the groundwater samples were decanted into sample containers provided by the laboratory. The sample containers were labeled with the project name, sample location, and the date and time the samples were collected. The samples were placed in a cooler containing ice to maintain the samples at 4 degrees Celsius, and transported to Research and Analytical Laboratories, Inc. (R&A) in Kernersville, North Carolina for chemical analysis. Proper chain-of-custody (COC) procedures were maintained throughout the sample collection and transportation process. A copy of the laboratory report and COC is included in the Appendix. Aquifer Parameters The relative elevations of the top of each well casing were previously measured by others to the nearest 0.01 feet using a level and rod. The elevations were measured relative to an arbitrary benchmark that was assigned an elevation of 100 feet. The relative elevation of the top of casing for each well and the measurement of the depth to groundwater surface from the top of the well casing were used to determine the relative elevation of groundwater at each well location. The groundwater elevations recorded on December 17, 2014 were used to prepare a groundwater flow map of the site (Figure 3). Based on Former Spray Exxon – Active Remediation Monitoring Report Eden, Rockingham County, North Carolina Progress Project No. 1015007.001 January 23, 2015 2 interpretation of the groundwater contours utilizing site monitoring wells, groundwater at the site flows generally to the southeast beneath the site. A summary of the monitoring well construction information is included in Table B-7. 3. LABORATORY RESULTS Monitoring Well Analytical Results Each of the groundwater samples collected from site monitoring wells MW-1, MW-2, MW-3, MW-4, MW-5, MW-7, and MW-1D were submitted to R&A to be analyzed for volatile organic compounds (VOCs) using Standard Method 6200B. Laboratory analysis of the groundwater sample collected from monitoring well MW-1 detected benzene (20.5 µg/L), naphthalene (102 µg/L), and total xylenes (1,560 µg/L) at concentrations that exceed their respective North Carolina 2L Groundwater Quality Standards (NC2LGWQS). Additionally, benzene was detected at a concentration that exceeds its North Carolina 2B Surface Water Standard by a factor of ten. Laboratory analysis of the groundwater sample collected from monitoring well MW-3 detected benzene (25.9 µg/L) and n-propylbenzene (169 µg/L) at concentrations that exceed their respective NC2LGWQS. Additionally, benzene was detected at a concentration that exceeds its North Carolina 2B Surface Water Standard by a factor of ten. Laboratory analysis of the groundwater sample collected from monitoring well MW-7 detected benzene (497 µg/L), ethylbenzene (1,320 µg/L), isopropylbenzene (87.5 µg/L), naphthalene (78.8 µg/L), and n-propylbenzene (268 µg/L) at concentrations that exceed their respective NC2LGWQS. Additionally, benzene and ethylbenzene were detected at concentrations that exceed their respective North Carolina 2B Surface Water Standard by a factor of ten. Laboratory analysis of the groundwater samples collected from monitoring well MW-2, MW-4, MW- 5, and MW-1D did not detect targeted petroleum-related compounds above their respective NC2LGWQS or the applicable North Carolina 2B Surface Water Standards by a factor of 10. None of the compounds detected exceed the applicable Gross Contamination Levels (GCLs). A summary of the laboratory analytical results is included in Table B-4. The laboratory data sheets are included in the Appendix 4. CONCLUSIONS Based on the results of the assessment, Progress concludes the following: Monitoring wells MW-1, MW-2, MW-3, MW-4, MW-5, MW-7, and MW-1D were purged and sampled. Monitoring well MW-6 contained approximately 0.03 feet of free product and, therefore, was not sampled. Laboratory analysis of the groundwater samples collected from monitoring wells MW-1, MW-3, and MW-7 detected targeted petroleum-related compounds at concentrations that exceed their respective Former Spray Exxon – Active Remediation Monitoring Report Eden, Rockingham County, North Carolina Progress Project No. 1015007.001 January 23, 2015 3 NC2LGWQS and/or the 2B Surface Water Standards by a factor of 10; however, the concentrations do not exceed the applicable North Carolina risk-based GCLs. Laboratory analysis of the groundwater samples collected from monitoring well MW-2, MW-4, MW- 5, and MW-1D did not detect targeted petroleum-related compounds above the NC2LGWQS or the 2B Surface Water Standards by a factor of 10. Groundwater was determined to be flowing to the southeast beneath the site towards the Smith River. 5. RECOMMENDATIONS Based on the results of this investigation, Progress recommends the following: Based on the concentrations of targeted petroleum-related compounds remaining below the applicable GCLs, it is Progress’ opinion that the incident continues to meet the criteria for classification as an “Intermediate Risk” incident. Free product and the highest concentrations of petroleum-related compounds were detected in off- site monitoring wells MW-6 and MW-7, respectively, located downgradient of the Spray Exxon. Monitoring well MW-6 is located at 108 Boone Road. Monitoring well MW-7 is located at 102 Boone Road. Please note, monitoring well MW-6 is in close proximity to a UST that was previously removed by the North Carolina Leaking Underground Storage Tank State Lead Program on the 102 Boone Road property. It is Progress’ opinion that the free product and dissolved-phase groundwater contamination identified in monitoring wells MW-6 and MW-7, respectively, are not the result of the release at the Spray Exxon site. Progress recommends installing a monitoring well in the vicinity of SVE-1 and OBS-1 to determine the groundwater quality on the southern side of the canopy in an effort to characterize the groundwater contaminant plume beneath the site. During the installation of the monitoring well, Progress recommends collecting and testing soil samples. 6. QUALIFICATIONS OF REPORT The activities and evaluative approaches used in this assessment are consistent with those normally employed in hydrogeologic projects of this type. Our evaluation of site conditions has been based on our understanding of the site project information and the data obtained during our field activities. FIGURES Figure 1 Topographic Site Map Former Spray Exxon 103 Boone Road Eden, Rockingham County, North Carolina P.O. Box 5884 Winston-Salem, NC 27113 Telephone: (336) 722-9999 Fax: (336) 722-9998 www.progressenvironmental.com United States Department of the Interior USGS 7.5 Minute Series Topographic Map Contour Interval: 10 feet Scale: 1”=2000’ Northwest Eden, NC-VA Date: 1965, Photorevised 1978 Southwest Eden, NC Date: 1971, Revised 1994 Southeast Eden, NC Date: 1971, Revised 1994 Northeast Eden, NC-VA Date: 1965, Photorevised 1983 Project: Former Spray Exxon Client: Eden Oil Progress Job #: 1015007.001 Date: January 2015 SITE Site REV 0 DRAWINGTITLE DRAWINGNUMBER FIGURE2 LEGEND MonitoringWellLocation SitePlanFormerSprayExxon 103BooneRoadEden, NorthCarolina DR.: JAB JAN15 CK.: JSL APP'D.: SCALE:SHOWN PROGRESSNO.: 1015007.001 www.progressenvironmental.com P.O. Box5884Winston-Salem,NorthCarolina27113(336)722-9999 Progress Environmental,Inc. N EW MW-12 SVE-1 OBS-1 MW-4 MW-1 MW-5 MW-6 MW-3 MW-1D MW-2 MW-4 MW-7 N EW REV 0 DRAWINGTITLE DRAWINGNUMBER FIGURE4 LEGEND MonitoringWellLocation GroundwaterAnalytical ResultsMapFormerSprayExxon 103BooneRoadEden, NorthCarolina www.progressenvironmental.com DR.: JAB JAN15 CK.: JSL APP'D.: SCALE:SHOWN PROGRESSNO.: 1015007.001 P.O. Box5884Winston-Salem,NorthCarolina27113(336)722-9999 Progress Environmental,Inc. N EW SVE-1 OBS-1 MW-4 MW-5 IPE 0.55 ug/L MW-7MW-1Benzene 20.5 ug/LEthylbenzene 401 ug/LIPE 54.5 ug/LIsopropylbenzene 17.5 ug/LNaphthalene 102 ug/Ln-Propylbenzene 51.7 ug/LToluene 123 ug/L1,2,4-Trimethylbenzene 374 ug/L1,3,5-Trimethylbenzene 92.7 ug/LTotal xylenes 1,560 ug/L MW-3 MW-2 IPE 0.69 ug/L Benzene 497 ug/Ln-Butylbenzene 17.5 ug/LEthylbenzene 1,320 ug/LIPE 33.5 ug/LIsopropylbenzene 87.5 ug/LNaphthalene 78.8 ug/Ln-Propylbenzene 268 ug/LToluene 59.8 ug/L1,2,4-Trimethylbenzene 202 ug/L1,3,5-Trimethylbenzene 67 ug/LTotal xylenes 414 ug/L MW-6Free Product Benzene 25.9 ug/Ln-Butylbenzene 10.8 ug/Lsec-Butylbenzene 10.4 ug/LEthylbenzene 12.1 ug/LIPE 15.2 ug/LIsopropylbenzene 38.9 ug/LNaphthalene 2.46 ug/Ln-Propylbenzene 169 ug/Lp-Isopropyltoluene 1.54 ug/LToluene 1.68 ug/L1,2,4-Trimethylbenzene 1.04 ug/L1,3,5-Trimethylbenzene 23.3 ug/LTotal xylenes 11.3 ug/L MW-4Not Detected MW-1D IPE 4.40 ug/LMTBE 10.0 ug/L TABLES Well IDDate Collected (m/dd/yy)Depth to Water (Ft. Below TOC)1/21/2013 12.51386BQL BQL BQL1,100 55.0 31.0JBQL232 78.0BQL694 909 249 5,070BQL12/17/2014 13.6920.5BQL BQL BQL401 54.5 17.5BQL102 51.7BQL123374 92.7 1,560BQL1/21/2013 12.23 BQL BQL BQL0.14JBQL2.51BQL BQL BQL BQL BQL BQL BQL BQL BQL BQL12/17/2014 14.03 BQL BQL BQL BQL BQL0.69BQL BQL BQL BQL BQL BQL BQL BQL BQL BQL1/21/2013 12.7922.0 14.1 14.2BQL42.0 6.45 86.9BQL10.2 264 4.20 2.20J 2.75BQL28.6BQL12/17/2014 13.3025.910.8 10.4BQL12.1 15.2 38.9BQL2.46 169 1.54 1.68 1.04 23.3 11.3BQL1/21/2013 12.53 BQL BQL BQL BQL BQL BQL BQL BQL BQL BQL BQL BQL BQL BQL BQL BQL12/17/2014 12.94 BQL BQL BQL BQL BQL BQL BQL BQL BQL BQL BQL BQLBQL BQL BQL BQL1/21/2013 15.550.55BQL BQL BQL BQL0.68 0.23JBQL0.10J 0.33JBQL BQL0.11JBQL0.19JBQL12/17/2014 17.52 BQL BQL BQL BQL BQL0.55BQL BQL BQL BQL BQL BQL BQL BQL BQL BQL1/21/2013 17.074,600 15.0JBQL BQL510 740 87.5BQL46.0 227BQL164 80.0 49.0 693 3,31012/17/2014 NA1/21/2013 16.001,430 16.5J 11.0JBQL835 96.5 79.0BQL27.5 240 5.0J 90.5 187 74.5 430 1,37012/17/2014 17.1749717.5BQL BQL1,32033.5 87.5BQL78.8 268BQL59.8 202 67 414BQL1/21/2013 12.86 BQL BQL BQL BQL BQL3.22BQL15.9BQL BQL BQL BQL BQL BQL BQL BQL12/17/2014 12.92 BQL BQL BQL BQL BQL4.40BQL10.0BQL BQL BQL BQL BQL BQL BQL BQL1 70 70 70 600 70 70 20 6 70 25 600 400 400 500 405,000 6,900 8,500 70,000 84,500 70,000 25,000 20,000 6,000 30,000 11,700 260,000 28,500 25,000 85,500 40,0001.19 420 NS 5.6 97 (LD) 250 19 12 1,700 (LD) 11 (LD) 130 670 NS = Values are those that exceed the North Carolina 2L Groundwater Quality Standard and/or 2B Surface Water Standards by a factor of 10 = Values are those that exceed the Gross Contamination LevelsItalics = Values are those that exceed the North Carolin 2B Surface Water Standards by a factor of 10ND = not detected above laboratory detection standardResults are reported in µg/lµg/L = micrograms per literGCL = gross contamination levelTOC = top of casingNS = No Standard(LD) = Limited DataMW-1DMW-7MW-1MW-2MW-3MW-4MW-5MW-6Tert-amyl AlcoholTotal Xylenes1,3,5-Trimethylbenzenen-PropylbenzeneNaphthalenep-IsopropyltolueneTolueneNC2LGWQS (µg/L)n-Butylbenzenesec-ButylbenzeneChloroformTABLE B-4SUMMARY OF GROUNDWATER ANALYTICAL RESULTSINCIDENT NAME AND NO.: SPRAY EXXON, 13568Analytical MethodSM 6200BACTIVE REMEDIATION MONITORING REPORTFREE PRODUCT2B Surface Water Standard (µg/L)MTBE1,2,4-TrimethylbenzeneDi-isopropylether (IPE)IsopropylbenzeneGCL (µg/L)BenzeneEthylbenzeneContaminant of Concern Well Screened Total Depth to Monitoring Well Installation Diameter Interval Depth to WaterID Date (inches) (feet) (feet) (feet TOC)12/17/2014MW-1 12/1/2000 2 14-29 29 99.54 13.69 85.85MW-2 10/11/2001 2 10-20 20 100.92 14.03 86.89MW-3 10/11/2001 2 9-19 19 97.82 13.30 84.52MW-4 10/11/2001 2 7-17 17 97.86 12.94 84.92MW-5 12/3/2001 2 10-20 20 98.55 17.52 81.03MW-6 8/30/2002 2 8-23 23 100.52 NM NMMW-7 3/19/2003 2 15-25 25 NM 17.17 NMMW-1D 10/12/2001 2 33-45 45 99.55 12.92 86.63Elevation of Groundwater (feet)Elevation of Top of Casing (feet)INCIDENT NAME AND NO.: SPRAY EXXON, 13568TABLE B-7MONITORING WELL CONSTRUCTION INFORMATIONACTIVE REMEDIATION MONITORING REPORT APPENDIX