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jj1 11 • Quik Stop No 121 Additional On-Site and Offsite Soil and Groundwater Investigation Page 6 and xylenes (BTEX), using EPA Test Methods 8015 and 8020, and volatile organic compounds using EPA Test Method 8260 Tables 2 and 3 present a summary of the groundwater analysis data from both the CPT borings and the site monitoring wells The laboratory reports and chain- of-custody forms are attached in Appendix B Discussion Groundwater Conditions The three on-site groundwater monitoring wells (screened from approximately 9 to 24 feet) were sampled and found to be impacted with petroleum hydrocarbons and MTBE Monitoring well MW-1, located on the northwest side of the site (Figure 4), near the intersection of Union Road and West Louis Avenue, was reported to have TPHg at a concentration of 690 ug/l, benzene at 0 84 ug/l and MTBE at 940 ug/1 Monitoring well MW-2, also located on the north side of the site, was reported to be free of detectable TPHg and BTEX compounds, however this well was reported to contain 9 9 ug/l MTBE Monitoring well MW-3, located on the southeast side of the property, was reported to contain 55,000 ug/l TPHg, with no BTEX compounds reported This . well was reported to have MTBE at a concentration of 52,000 ug/l Depth-to-groundwater measured in the three site wells ranged from 17 54 to 18 13 feet below the ground surface The groundwater flow direction within the shallow aquifer is calculated to be toward the southeast, at a gradient of 0 003 feet per foot (Figure 4) Groundwater samples collected from two depth intervals (17 to 20 feet and 37 to 40 feet) at CPT- 2, located approximately 325 feet to the southeast of the subject site, were reported to be free of TPHg and benzene and MTBE compounds The water sample collected at CPT-3, located on the north side of West Louis Avenue, from a depth of 12 to 16 feet, was reported to contain 85 ug/l TPHg In addition, CPT-1, located approximately 20 feet southeast of monitoring well MW-3, was reported to contain 57 ug/l MTBE and 5 ug/l tetrachloroethene at a depth of 35 to 38 feet No other petroleum hydrocarbons or VOCs were detected at this location Conclusions Based on the information obtained during this investigation, as well as from previous investigations conducted at the site, it appears the groundwater is impacted with petroleum hydrocarbons, mainly in the vicinity of Quik Stop Markets' fuel tanks on the southeast side of the site, near monitoring well MW-3 Low concentrations of TPHg were detected in the shallow water sample collected on the north side of West Louis Avenue, in front of the Exxon gas station Since this location is up-gradient of the Quik Stop site, the TPHg detected at CPT-3 may be associated with the Exxon site