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barmea 145Soah Suffia-Sinvars,ncemn. Coa,ona BACKGROUND In Maroh 2009, the monitoring wells were surveyed in order to determine the groundwater flow at the site. The moults of the survey and suhsequent gradient calculations identified that the groundwater How direction is towards the east and that the contaminant plume may be located between wells M W-7 and M W-6. In Juno, 20081 mil boring 1311-14 was drilled to I10 fat bgs along the East Washington Street sidewalk m assess the venial extent of petroleum hydrocarbons previously detected in samples collectedf bottom of boring 1314-13. Six soil samples selected for laboratory analyses at depths ranging Sam 50 feet to 110 fat has. Total pclmleum hydmcnibons as gasoline (TPH-g) was detectN at35 mg/kgand [30 mg%gfimm sampling depths of50 feetand 55 f bgs, respectively. Henan was detected in only one soil sample collected Drum 85f bgs at a concemmtion of5.7 pglkg. A groundwater "grab" sample was collected from at a depth of I I I feet bgs and contained 6,900 Us/D, WH-g, 81 pg/L bemese, and delectable concentrations o]'toluere, ethyl6enune and xylenes. Ile laboratory reported flat the sample also contained 5,600 ga of unknown hydrocarbons in the diesel range. The diesel analysis chromatograms bar the groundwater sample contain heavy end of gasoline hydrocarbons (C 10 to C12) which are detected and reported as the light end of dieted. These commentaries are greater than what would be expected to be f umi in a monitoring well and are biased high due to the dawdown of communication from above by the hollow ram augers. In June 2008, while attempting to install groundwater nronitoring well MW-10 in the sidewalk along Somh Sutter Street, a UST was found with an air knife and vacuum truck while clearing the well location for underground utilities In July 2008, a geophysical survey was conducted along the sidewalk from the comer of Izat Washington and South Sutler Strects to the location of the former US Is north of the former services ion. The geophysical survey identified live electromagnetic anomalies and one ground penetrating radar anomaly along the sidewalk. One of the anomalies was aligned with the newly discovered UST; however, interfrenec from mbar and woe mesh in the sidewalk limited the effectiveness of Inc survey. The geophysical Covey anomalies went investigated by excavating the areas using an air knife and vacuum track after caving through the sidewalk. Five 10 inchdiameter borings were excavated to a depth of 10 rest