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Chronology 5157 Business Loop, Tracy Page 2 <br /> 11/09/07 One Cone Penetrometor Test (CPT) boring was advanced onsite to total depth of <br /> 110 feet below surface grade (bsg). Two -!grab groundwater samples were <br /> collected, one from 64-69 feet bsg and one from 75-79 feet bsg. Both samples <br /> were reported to be impacted by petroleum, hydrocarbon constituents, but the <br /> deeper boring was at much higher concentrations. See AGE report "Cone <br /> Penetrometor Testing Site Investigation Fourth Quarter 2007' dated May 2, <br /> 2008. <br /> 08/28/09 One deep groundwater monitoring well, MW-13, . was installed to verify the <br /> detection .of contaminants at the 75-79 foot bsg CPT sample. Laboratory <br /> analytical results were reported as non-detect at two consecutive sampling <br /> events. See AGE report "Monitoring Well Installation - Third Quarter 2009" <br /> dated September 28, 2009. <br /> 11/17/09 Date of"No Further Action Request" report submitted by AGE. In the Report AGE <br /> estimates the following: <br /> 1. 166 gallons of gasoline were removed during the over-excavation <br /> remediation. <br /> 2. 54-gallons-of-gasoline-remain-adsorbed-to the soil. <br /> 3. Approximately 0.31 lbs of dissolved TPHg and 0.02 lbs of dissolved benzene <br /> .remain in the groundwater. <br /> 4. Dissolved TPHg concentrations will reduce to non-detect by 2013 and <br /> dissolved benzene concentrations will reduce totion-detect by 2018. <br /> 5. The site passes the SFBRWQCB ESL screening levels for TPHg and poses <br /> no threat of vapor intrusion. <br /> AGE concludes that the site is defined, the concentrations are declining, and they <br /> recommend site closure. <br /> f <br /> E <br /> E ' <br />