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, t <br /> Ms. Diane Lundquist <br /> October 8, 19W <br /> Page 2 i <br /> TABLE 1 <br /> Sod Boring Soil Sample Analytical Results(ppm) <br /> Sample Depth Ethyl- <br /> Location ft below rade Benzene Toluene benzene Xylenes TPHa <br /> MW8-2 25 074 023 0 045 0 54 6 0 <br /> MW8-3 30 0 32 0 036 0 056 0 050 30 <br /> MW9-1 20 42 350 60 420 4,400 <br /> MW9-3 30 055 1.2 060 50 69 <br /> aTotal petroleum hydrocarbons as gasoline <br /> Soil samples obtained from the monitoring well soil borings were field-analyzed for the presence of <br /> petroleum hydrocarbon vapors with a flame ionization detector (FID) FID screening results are <br /> indicated on the soil boring logs (Enclosure B) Soil samples were selected for chemical analysis on the <br /> basis of FID screening results and the location of the soil sample in relation to the water table <br /> Soil samples submitted from the borings contained detectable concentrations of TPH Soil samples <br /> collected from the soil boring of MW-8 at depths of 25 and 30 feet below grade contained TPH <br /> concentrations of 6 and 3 parts per million (ppm), respectively Soil samples collected from the soil <br /> boring of MW-9 at depths of 20 and 30 feet below grade contained TPH concentrations of 4,400 and <br /> 69 ppm, respectively <br /> Ground Water Analytical Results <br /> Ground water samples were collected and submitted for chemical analysis of BTEX and TPH <br /> concentrations on March 28 and July 31, 1990 The analytical laboratory results of groundwater samples <br /> collected since December 1989 are compiled in Table 2, and copies of the certified laboratory reports <br /> for the March and July 1990 sampling events are included in Enclosure E <br /> Ground water sample analytical results indicate that benzene concentrations in samples collected from <br /> MW-1 have increased from nondetectable to 0 00 13 ppm in the period between March and July 1990 <br /> Water samples collected from MW-5 and MW-8 have also increased in benzene concentrations The <br /> upgradient monitoring well (MW-6) has remained below detection limits for March and July 1990 <br /> Monitoring well MW-9 was not sampled because of the presence of a thin layer of free-phase petroleum <br /> product in the monitoring well <br />