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LFR Inc. Table 3: Well Construction Summary for Wells MW-1 through MW-9 Well Boring Boring Well PVC Screen Filter Pack Screen Filter Bentonite Annular 1.D. Depth Diameter Depth Casing Slot Material Interval Pack Bridge Seal (feet (inches) (feet Diameter Size (feet Interval Interval Interval bgs) bgs) (inches) (inches) bgs) (feet (feet bgs) (feet bgs) bgs) MW-1 NA NA 95 2 NA NA NA NA NA NA MW-2 NA NA 71 2 NA NA NA NA NA NA MW-3 NA NA 90 2 NA NA NA NA NA NA MW-4 NA NA 101 2 NA NA NA NA NA NA MW-5 121.5 8 121 2 0.01 #2/12 sand 101-121 91-121 94-97 0-94 MW-6* 124 8 122 2 0.01 #2/12 sand 102-122 99-122.5 94-99 0-94 MW-7 125 8 121 2 0.01 #2/12 sand 101-121 98-125 94.5-98 0-94.5 MW-8 125 8 120 2 0.01 #2/12 sand 100-120 98-125 94-98 0-94 MW-9 125 8 115 2 1 0.01 #2/12 sand 95-115 92-125 89-92 0-89 Notes: NA = Information not available; previously installed by U.S. EPA's contractor, EEI * = Well MW-6 was destroyed on April 14, 2006, in accordance with San Joaquin County standards and as described in Section 5.5.2 of this report. 5.5.4 Summary of Sampling Results Based on groundwater sampling results from wells MW-1 through MW-5 during the eight quarterly sampling events conducted during the second quarter of 2003 through the second quarter of 2005, general minerals and metals in the collected groundwater samples appear to reflect background conditions. Organic compounds (TRPH, VOCs, and SVOCs) were not detected in groundwater samples collected from the five on-site wells during the eight quarterly groundwater sampling events. Pyrolytic oil was encountered in soil during excavation activities in the north- northwestern corner of the Site ("the source area") during July 2005. The pyrolytic oil was observed at the groundwater table interface and diesel-range petroleum hydrocarbons (TPHd) were detected in groundwater samples collected from soil borings SB-1 (51,000 micrograms per liter [Ag/1]) and SB-2 (5,100 gg/1) and monitoring well MW-6 (1,000 gg/1), which were drilled/installed approximately 50 feet downgradient from the source area. Additionally, TPHd was detected in groundwater samples collected from well MW-8, which was installed approximately 200 feet north- northwest of(downgradient from) the Site, during February 2006 (2,500 gg/1) and June 2006 (200 gg/1). Diesel-range petroleum hydrocarbons (970 jig/1) and motor oil-range petroleum hydrocarbons (370 gg/1) were detected in the groundwater sample collected from well MW-9 on July 14, 2006. Page 28 rpt-RA summ-Nov06-final-09025:FNC