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C <br /> May 23, 2001 <br /> Ms Margaret Lagono <br /> Page 2 <br /> • A total of five Geoprobe®borings (GP-I through GP-5) were completed on August 15 and 16, <br /> 2000 using a direct push ng The bonngs were advanced to groundwater at which time a discrete <br /> water sample was collected Following groundwater sample collection the borings were <br /> continued to a maximum depth of 30 feet bgs <br /> Three groundwater monitoring wells (MW-1 through MW-3) were installed on September 6, <br /> 2000 at the locations shown on Figure 2 The well locations were selected based upon results of <br /> the Geoprobe®investigation <br /> GROUNDWATER MONITORING RESULTS <br /> Groundwater samples and depth to water data were collected on April 23, 2001 from monitoring <br /> wells MW-1 through MW-3 The groundwater monitoring event was coordinated with the Blaine <br /> Tech Environmental who monitors the 76 Station east of the subject site Groundwater samples <br /> were analyzed for the presence of total petroleum hydrocarbons as gasoline (TPH-g), benzene, <br /> toluene, ethylbenzene, xylenes (BTEX compounds), and for five gasoline oxygenates (MtBE, <br /> DIPE, ETBE, TAME and TBA) using EPA Methods 8015 Modified, 8020 and 8260, <br /> respectively Field and laboratory procedures are presented as Attachment A Certified <br /> analytical reports, chain-of-custody documentation, and field data sheets are presented as <br /> Attachment B <br />• Second Quarter Groundwater Monitoring Results <br /> Groundwater levels at the site have increased 0 96 foot since the previous sampling event on <br /> January 19, 2001 Groundwater flow during the second quarter was generally to the northeast <br /> with an average gradient of 0 0008 ft/ft, which is consistent with the previous sampling event <br /> Groundwater elevation data are presented in Table 1 A groundwater elevation contour map <br /> based on the April 23, 2001 data is shown on Figure 1 <br /> TPH-g was detected in wells MW-1 and MW-3 at concentrations of 19,000 pg/L and 1,160 µg/L, <br /> respectively Benzene was detected to wells MW-1 and MW-3 at concentrations of 1,780 µg/l, <br /> and 6 3 pg/L, respectively MtBE was detected in wells MW-1, MW-2 and MW-3 at <br /> concentrations of 39,500 µg/L, 10,400 µg/L and 683 µg/L, respectively TAME was reported in <br /> wells MW-1, MW-2 and MW-3 at concentrations of 285 pg/L, 67 5 pg/L and 4 23 pg/L, <br /> respectively TBA was reported in wells MW-I and MW-2 at concentrations of 4,780 µg/L and <br /> 697 gg/L, respectively Groundwater analytical data is presented in Table I A TPH-g, benzene, <br /> and MtBE concentration map based on the April 23, 2001 data is shown on Figure 2 <br /> CONCLUSIONS <br /> Groundwater levels have increased 0 96 foot since the first quarter 2001 sampling event <br /> Groundwater samples indicate an increase in TPH-g, BTEX and oxygenate constituents since the <br /> previous sampling event Oxygenate concentrations have decreased in MW-2 TPH-g, BTEX <br /> and oxygenate constituents have remained consistent with the previous sampling event in MW-3 <br /> \\SAC-RFP IICOMMONIrancfp1\Projects\Projects1880\040U a\01 07\8 800402qO I doe <br />