Laserfiche WebLink
~ San Joaquin County <br /> Environmental Health Department DI Donna <br /> H <br /> Donna Heron, REHS <br /> r. ` 1868 East Hazelton Avenue <br /> -A PROGRAM COORDINATORS <br /> Stockton , California 95205 -6232 Robert McClellon , REHS <br /> — Jeff Carruesco, REHS, RDI <br /> Website: www.sjgov. org/ehrl Kasey Foley, REHS <br /> � rFoe Linda Turkatte, REHS <br /> Phone: (209) 468-3420 Rodney Estrada, REHS <br /> Fax: (209) 464-0138 Adrienne Ellsaesser, REFS <br /> April 25, 2013 <br /> Brian A. Waite, P. G. <br /> Chevron Environmental Management Company <br /> 6101 Bollinger Canyon Road , BRIX-5321 <br /> San Ramon , CA 94583 <br /> RE: Chevron #9-4054 <br /> 2103 Country Club Blvd. <br /> Stockton, CA 95204 <br /> The San Joaquin County Environmental Health Department (EHD) has reviewed Low Threat <br /> Closure Request (Report) dated February 19, 2013 submitted on your behalf by Arcadis. In the <br /> Report, Arcadis states that the site qualifies for low-threat closure and presented an evaluation <br /> of site conditions against the Low Threat Closure Policy (LTCP) criteria . The EHD reviewed the <br /> LTCP criteria, site investigations, characterization and corrective actions taken to evaluate the <br /> site for closure . The EHD determined that the site does not qualify for closure consideration <br /> under the LTCP for the following reasons: <br /> 1 ) The secondary source has not been removed to the extent practicable; <br /> 2) The most intensely impacted groundwater in the "B" zone has not been adequately <br /> defined; and <br /> 3) Dissolved benzene concentrations in the " B" zone exceed the 1 ,000 micrograms per <br /> Liter=(ug/E)=maximum-concentration of-the Groundwater=Specific=Gritefia=(4d)=and-the <br /> 3, 000 ug/L maximum concentration of the Groundwater Specific Criteria (2d) . <br /> Secondary source removal consisted of local excavation to approximated 10 feet below surface <br /> ground (bsg) and operation of a Dual Phase Extraction (DPE) system from the year 2000 to <br /> 2002J'The Soil Vapor Extraction (SVE) portion of DPE is estimated to have removed 2 , 180 lbs <br /> of contaminants from the vadose zone ranging from 8 to 12 feet bsg during the operational <br /> period . The most intensely impacted soil has been encountered in the saturated zone between <br /> 15 and 30 feet bsg and would not have been directly impacted by the SVE portion of the DPE. <br /> The EHD did not find an estimate of the contaminant mass removed by the Ground Water <br /> Extraction (GWE) portion of the DPE , but notes that the average Total Petroleum Hydrocarbons <br /> gas (TPHg) of 20-foot soil samples collected after DPE was 2, 912 mg/kg , greatly exceeding the <br /> concentrations of the 20-foot samples collected during and prior to the DPE operation average <br /> of 927 mg/kg . These contaminant concentrations relationships are not suggestive of effective <br /> remediation of impacted soil at 20 feet bsg . <br />