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Page 1 of 2 <br /> r.r 4d <br /> Vicki McCartney [EH] <br /> From: Barton, Jim@Waterboards[jim.barton@waterboards.ca.gov] <br /> Sent: Tuesday, February 19, 2013 6:31 AM <br /> To: Vicki McCartney [EH] <br /> Cc: Nuel Henderson [EH] <br /> Subject: RE: 308 South EI Dorado Street in Stockton <br /> Thanks Vicki. Please do so. <br /> Jim Barton <br /> James L. L. Barton P. G. <br /> Central Valley Regional Water Quality Control Board <br /> 11020 Sun Center Drive,#200 <br /> Rancho Cordova, CA 95670-6114 <br /> Office (916)464-4615 <br /> Fax (916)464-4704 <br /> From: Vicki McCartney [EH] [mailto:vmccartney@sjcehd.com] <br /> Sent: Friday, February 15, 2013 4:26 PM <br /> To: Barton, Jim@Waterboards <br /> Cc: Nuel Henderson [EH] <br /> Subject: 308 South EI Dorado Street in Stockton <br /> Jim: <br /> Yesterday at our Unit IV meeting, I was not prepared to talk to you about closing the Den's Auto Repair <br /> site at 308 South El Dorado Street in Stockton even though this site was on the agenda. I have <br /> completed the review of the No Further Action Required Report and believe this site is ready for <br /> closure based on the following: <br /> • The source of the contamination has been removed; <br /> • The plume appears to be stable or shrinking; <br /> • Cal-Water is the water purveyor for this site; <br /> • There are no active water supply wells within 1,000 feet of the site; <br /> • The groundwater plume appears to be vertically and laterally delineated; <br /> • The contaminant plume that exceeds water quality objectives(WQO) is about 100 feet in length; <br /> • Although total petroleum hydrocarbons as gasoline (TPH-g) concentrations in Hydrologic Unit 2 <br /> (HU-2) [-45 to 90 feet below surface grade (bsg)] do not show a decreasing trend, Advanced <br /> GeoEnvironmental, Inc. (AGE) projected that dissolved TPH-g will reach WQO in about five years <br /> in HU1 and about two years in HU3; and dissolved benzene will reach WQO in about one year <br /> in HU1 and HU3 and about six years in HU2; <br /> • The estimated mass of dissolved TPH-g was approximately 3.3 pounds; <br /> • The estimated mass of adsorbed TPH-g was approximately 1,500 pounds; <br /> • AGE stated that residual soil contamination left in place will not pose a significant threat to human <br /> health or the environment since: the surface is paved and no impacted soil is exposed; although <br /> soil samples were not collected and analyzed in the shallow depths, when advancing borings B2 <br /> and B4 (MW-1), OVA readings were reported at zero at 5 and 10 feet bsg on the boring logs; <br /> benzene concentrations detected in soil samples collected at 16 feet bsg were below the <br /> commercial Environmental Screening Levels (ESLs)for gross contamination and direct exposure; <br /> 2/19/2013 <br />