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r • Quik Stop Market No 121 CCI Prod ect No 12118-2 Page 4 7, located on the east side of the site (both wells are screened from 10 to 25 feet) were reported to contain 310 ug/l and 2 ugh MTBE, respectively Deep well MW-6, screened from 65 to 75 feet, was reported to contain 78 ug/l TPHg, minor concentrations of BTEX compounds and MTBE at 29 ug/l The results of the groundwater analysis are summarized in Table 2 The analytical reports from North State and chain-of-custody documents are attached in Appendix D Discussion Based on the groundwater data obtained during the quarterly sample round, it appears the groundwater is impacted with petroleum hydrocarbons, mainly in the vicinity of Quik Stop Market's fuel tanks on the southeast side of the site, near monitoring wells MW-3 and RW-1, and on the northwest side at MW-1 (Figures 3, 4 and 5) Groundwater samples collected from the perimeter wells MW-2, MW-5 and MW-7 are reported to have detectable TPHg and MTBE compounds, although at relatively low concentrations when compared to levels reported near the site fuel tanks Recently installed monitoring well MW-8 was reported to be free of TPHg and had minor concentrations of ethylbenzene and total xylenes This well was reported to have 0 8 ug/l MTBE Groundwater in the vicinity of monitoring wells MW-3 and RW-1 were reported to have the highest contaminant concentrations of TPHg and MTBE at the subject site It appears some TPHg and MTBE has migrated to a lower portion of the aquifer, at a depth of 33 to 43 feet, as detected in the water sample collected at MW-4 and was detected from the deepest site well (screened from 65 to 75 feet) as reported at MW-6 Groundwater measurements taken in the seven monitoring wells screened from 9 to 24 feet on April 18, 2001 indicated the depth-to-groundwater ranged from approximately 16 29 to 16 98 feet below the top of the well casings The water level in monitoring well MW-4 (screened from 33 to 43 feet) was measured at 16 04 feet below the top of the well casing and monitoring well MW-6 (screened from 65 to 75 feet) was measured at 2193 feet The water table has risen approximately %2 foot since the January 2001 sample round The one exception was monitoring well MW-6, in which the water table dropped approximately 11 feet since January 2001 Groundwater contours in the vicinity of the site monitoring wells indicate the groundwater surface to be slightly depressed in the vicinity of monitoring wells MW-3 and MW-4, with slightly higher elevation at perimeter wells MW-1, MW-2, MW-5, MW-7 and MW-8 The groundwater flow direction appears to be from the east and from the north toward monitoring well MW-4 at a gradient of approximately 0 003 feet per foot, (Figure 6) In response to San Joaquin County Public Health Services, Environmental Health Division (County) April 23, 2001 letter, CCI is currently working on a Work Plan for additional Well