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r <br /> Project No 034-98081 <br /> Page No 2 <br /> excavation The second boring (B-1), which did penetrate the former tank excavation, was advanced to a <br /> total depth of 20 feet below ground surface (bgs) Analytical results of soil samples collected from <br /> boring B-I revealed minor concentrations of PHCs Based on the results of the January 1998 drilling and <br /> rsampling activities, and prompted by UBOC, the lender for the site property, four additional Geoprobe® <br /> borings (P-1 through P-4) ranging in depth from 20 to 40 feet bgs were advanced in the vicinity of the <br /> former UST excavation on February 2, 1998 The analytical results of soil samples collected from the <br /> Geoprobet borings established both horizontal and vertical attenuation of PHCs in soils beneath the <br /> former UST However, because groundwater was anticipated to be within 10 feet of detectable <br /> concentrations of PHCs and impact to groundwater was unknown, property lender (UBOC) requested an <br />' additional assessment to determine potential groundwater impact by PHCs associated with the former <br /> UST <br /> On March 13, 1998, Krazan advanced a 46-feet deep Geoprobe® boring and collected a grab <br /> groundwater sample at the location of the former UST The groundwater sample was analyzed for PHCs, <br /> common fuel oxygenates, as the former UST was in place during the period of time when oxygenated <br /> fuels were being initially introduced into the market The groundwater sample contained elevated <br /> concentrations of PHCs, but no concentrations of fuel oxygenates or chlorinated hydrocarbons Upon <br /> receiving a copy of Krazan's report for the August 1998 investigation, the SJCEHD requested in an April <br />�! 13, 1998 letter to Wilbur-Ellis the installation of monitoring wells to complete the assessment process <br /> r <br /> 30 PURPOSE OF THE AUGUST 1998 ASSESSMENT <br /> t <br /> The purpose of the August 1998 investigation was to define the lateral and horizontal extent of possible <br /> PHC contamination in soil and groundwater, and to determine the optimum locations for monitoring well <br /> installation Based on historically fluctuating groundwater levels, the SJCEHD requested in their June <br /> 23, 1998 letter that Krazan modify their original work scope so that borings would be advanced and soil <br /> samples be collected and analyzed to a depth of 60 feet in the vicinity of the former UST excavation <br /> They also requested that monitoring well groundwater samples be analyzed for fuel oxygenate <br /> compounds <br /> K12AZAN& ASSOCIATES,INC <br /> Offices Serving the Western United States <br /> 3498081 SGS <br />