Laserfiche WebLink
Fourth Quarter 2002 Monitoring and Sampling Report 5 <br /> 7-Eleven, Inc, Store#21756,853 E Yosemite Avenue,Manteca,CA December 10,2002 <br /> ' All extracted vapor concentrations from wells SPV-2 and MW-1 were less than or equal to 8 parts per <br /> million by volume (ppm [v]) At an applied vacuum of 30 Inches of water in well SPV-2, Induced vacuum <br /> responses in wells MW-1 (located 24 feet from SPV-2) and MW-3 (located 27 feet from SPV-2) ranged up <br /> to 0 30 and 0 16 Inches of water, respectively Induced vacuum response in well MW-2 (located 43 feet <br /> from SPV-2) was less than 0 1 Inches of water and Indicates that this well is outside the effective ROI of <br /> SPV-2 At an applied vacuum of 30 Inches of water in well MW-1, Induced vacuum responses In wells <br /> ' MW-3 (located 55 feet from MW-1) and MW-2 (located 65 feet from MW-1) ranged up to 0 14 and 0 04 <br /> Inches of water, respectively Based on the Induced vacuum responses during the test, it appears that the <br /> SVE ROI is confirmed to be about 25-30 feet SVE ROI Field data sheets are Included in Attachment 3 <br /> ' These data Indicate that although the site exhibits vapor extraction capability <br /> g p using the existing well <br /> ' configuration, the overall hydrocarbon/oxygenate mass accessible by vapor extraction in the areas tested <br /> is relatively small, indicating the bulk of residual gasoline constituents at the site is in the saturated zone <br /> ' Conclusion and Recommendations <br /> Groundwater concentrations reported for the fourth quarter of 2002 indicate continued dissolved MTBE <br /> ' plume delineation, and stability of plume conditions with elevated MTBE concentrations confined to well <br /> MW-1 Well MW-1 is downgradient of boring location GP-3, which had the highest reported dissolved <br /> MTBE concentrations as of June 1999 Non-detectable levels of MTBE in furthest downgradient well MW- <br /> 4 verify continued downgradient delineation of the MTBE plume <br /> ' SVE testing data confirm that SVE potential is limited as a remediation process due to low vadose-zone <br /> mass, however, the SVE ROI is adequate If SVE should be pursued during air and/or oxygen sparging <br /> Sparging potential at this site is recommended for evaluation in 2003 <br /> 1 <br /> 1 <br />