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�l <br /> This data indicates that interim remediation performed by Wright in 1993 removed <br /> petroleum contaminants with low concentrations of highly degraded petroleum <br /> hydrocarbon contaminants remaining Volatile components (BTEX and MTBE and <br /> oxygenates) were not detected, and the laboratory reported that they did not match the <br /> gasoline standard suggestive of a degraded fuel The relatively high dissolved TPHG at <br /> B-3 is interpreted to represent degraded fuel in the capillary fringe or upper aquifer strata, <br /> which was released by the drilling/push sampling mixing action in that borehole <br /> Borings were placed both in and out of the streets, in near proximity to numerous <br /> subsurface utilities Based on the exploratory boring data, contaminant migration did not <br /> appear to occur in or along the utility backfill or trench runs (see Figure 4, utility location <br /> map) Wright is not aware of any reports of utility trenches contaminated by similar <br /> contaminants in this area <br /> Conclusions and Rccommendations <br /> Six borings were advanced in and around the former tank pit areas at Tracy Auto Stereo <br /> The soil and groundwater sample data show that low levels of degraded petroleum <br /> hydrocarbons occurred in capillary fringe samples in Borings B-1, B-3 and B-6 <br /> Dissolved contaminants were observed at B-1, B-2 and B-3, with the highest <br /> concentrations at B-3 Neither BTEX or MTBE and oxygenate contaminants were <br /> observed in either down gradient boring (B-4 and B-5) and were not observed in any <br /> underlying confining strata soil sample <br /> A former service station with three on-site monitoring wells occurs directly down <br /> gradient of Tracy Auto Stereo The status of this site is unclear, however the presence of <br /> wells and water recovery drums indicates this site is may still be in an "active" status <br /> The distribution of contaminants and pending action for this site is unknown at this time <br /> The tank removal and 1993 interim remediation activity appear to have removed the bulk <br /> of contaminants Residual contaminants remain in the area as observed at B-1, B-3 and <br /> B-6, in or near the perimeter of the excavated area In our opinion given the highly <br /> degraded condition of the petroleum hydrocarbons, depleted volatile content, and lack of <br /> contaminants observed at the down gradient boreholes, a widespread contaminant plume <br /> is not present <br /> Wright is submitting this report for PHS-EHD and City of Tracy review Pending this <br /> review and direction from PHS-EHD Wright will prepare as required workplan for <br /> monitoring well placement as indicated in previously approved workplan as directed by <br /> PHS-EHD <br /> Page 5 <br />