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' Up gradient monitoring well MW-1 was sampled a total of 15 tines between August 1998 and June 2002, and TPHd was only detected, at a concentration of 66 µg/L, in the samples collected in August 199$ No other sampling events detected the presence of TPHd, TPHg, or BTEX in MW-1 Similarly, ' groundwater samples collected during nine sampling events from downgradient wells MW-5 and MW- 6 between June 2000 and June 2002 did not detect TPHd,TPHg,or BTEX Additional ground water sampling from June 2004 detected TPHd in groundwater samples from monitoring wells MW-1, MW-5, and MW-6 (at concentrations of 59, 250, and 170 µg/1,respectively) However, groundwater samples collected from these wells in August and November/December 2004 ' contained no detectable concentrations of TPHd, TPHg, or BTEX using the silica gel preparation procedure Based on the historical results, the June 2004 results are considered anomalous(See Table 3 and 4 for ground water results) Deeper monitoring well M-W-7, placed east of the former UST excavation and screened at a depth of 30 to 35 feet,was sampled for the first time in June 2004 These results indicated the presence of TPHd (520,ug/L) and toluene(0 63 µg/L) These results were not confirmed with the August 2004 analytical results indicating no detectable TPHd, TPHg, or BTEX The November/December 2004 results reported the presence of TPHd(140 to 180 µg/L),however,when these samples were placed through a ' silica gel, no detectable TPHd concentrations were present This result indicates reported detections m these samples are non-petroleum biogenic material . The 2004 results for monitoring wells MW-3 and MW-4 indicate TPHd concentrations increased between 2002 and 2004 The groundwater gradient is flat in the area of MW-3 and MW-4 with a historical flow direction from MW-2 toward the south and southwest according to previous quarterly reports (Haley and Aldrich, 2004, and ATC 2002) Any material detected in MW-3 and MW4 is associated with the source area at MW-2 ' 33 Product Removal According to the CAP and previous reports, free phase petroleum has been sporadically observed in ' monitoring well MW-2, located within the backfill of the former tank excavation First a sheen was observed in December 2000 and then a thin layer of 0 01 to 0 2 feet was observed between June 2001 through August 2004 In August 2004, a petro trap was installed to collect any free product and to ' provide information regarding the characteristics of the free product Measurable free phase petroleum is likely limited to the area of the excavation backfill based upon the recovery of only 100 milliliters during recovery every two weeks'in September A petro trap will continue to be monitored ' to further assess the presence of free product 34 Potential for Migration Surfafe Water and Drinking Water Impacts ' As discussed in the October 2004 CAP, petroleum constituents from a release from the former UST have been in direct contact with groundwater for a minimum of at least 16 years, as the UST was ' removed in 1988 Groundwater analytical results indicate that petroleum analytes and constituents are only detected in samples collected from monitoring wells installed within affected soil 9 R ICONTGRAN\Stockton\CAPICAP ADDENDUM