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y ENVIRONMENTAL HEALTH YYEPARTMENT <br /> ° SAN JOAQUIN COUNTY <br /> z•' +—��►V Z Drama K. Heran, RX.H.S. Unit Supervisors <br /> Ni Director304 Cast Weber Avenue,Third Floor Carl Borgman,R.E.H.S. <br /> Laurie A. Cofulla, R.E.H.S. Stockton,California 95202-2708 Mike Huggins. R.E.H.S., R.D.I. <br /> rP Program Manager Douglas W. Wilson, REM,& <br /> Telephone: (209)468-3420 Margaret I-agorio,R.E.H.S. <br /> Fax: (209) 464-0138 Robert McClellon, R.E.H.S. <br /> Website: www.sjgov.org/elid/ Jeff Carruesco, R.E.H.S. <br /> BEVERLY GARCIA FEB 2 2 2006 <br /> RAYMOND INVESTMENT CORPORATION <br /> 817 SOUTH CENTER STREET <br /> STOCKTON CA 95206 <br /> RE: Raymond Investment Corporation SITE CODE: 1529 <br /> 730 Channel Street <br /> Stockton, California 95202 <br /> San Joaquin County Environmental Health Department(EHD)has reviewed the analytical results <br /> for groundwater samples collected during the five quarterly groundwater sampling events from <br /> November 8, 2004, through November 18, 2005, as well as soil and groundwater analytical <br /> results collected during the advancement of soil borings SBI through SB6 in May 2004 and the <br /> installation of monitoring wells MW-1, MW-2, MW-3, and MW-3R in September and October <br /> 2004, that were submitted by Condor Earth Technologies, Inc. (Condor) on your behalf. Based <br /> on the non-detect groundwater results for all chemicals of concern from the November 2005 <br /> sampling event and historical low concentration detections for diesel and gasoline during <br /> previous groundwater sampling events, Condor recommended consideration of case closure for <br /> this site. <br /> EHD cannot support a recommendation for site closure at this time for the following reasons. <br /> During the advancement of six soil borings in May 2004, high concentrations of diesel and <br /> gasoline were detected in soil borings SB3 and SB4 soil samples collected between six and thirty- <br /> two feet below ground surface (bgs) and grab groundwater samples collected between thirty-five <br /> and forty feet bgs. Soil was impacted only at thirty-two feet bgs in SB2 — probably capillary <br /> fringe zone. Groundwater has consistently been below that depth since groundwater monitoring <br /> was initiated. EHD does not believe that the vertical extent of impacted soil and groundwater has <br /> been demonstrated in the area where S133 and SB4 were advanced. Also, groundwater gradient <br /> has historically been toward the east-northeast at this site. Further groundwater and soil <br /> investigation will be necessary to assess the lateral extent of hydrocarbon contamination in the <br /> area of and down gradient of SB3. EHD believes that two or three additional monitoring wells, <br /> one adjacent to SB3, and one or two down gradient of SB3 are needed to assess lateral extent of <br /> groundwater contamination in this direction. Please submit a work plan to EHD by April 10, <br /> 2006,that addresses vertical and lateral extents of contamination at this site. <br /> EHD recommends a reduction for sampling monitoring well MW-3R from quarterly to annually <br /> since historically non-detect analytical results have been reported for ground- water samples <br /> collected from MW-3R for the five quarterly groundwater monitoring events. EHD also approves <br /> the removal of total petroleum hydrocarbons as kerosene (TPH-kerosene), TPH as motor oil <br /> (TPH-motor oil), methanol, ethanol, tertiary-butyl alcohol (TBA), di-isopropyl ether (DIPE), <br /> tertiary-amyl methyl ether (TAME), ethyl tertiary-butyl ether (ETBE), 1,2-dichloroethane (1,2- <br /> DCA), and 1,2-dibromoethane (EDB) from the analytical list of compounds for the three existing <br /> onsite monitoring wells. This analyte reduction does not apply to groundwater samples collected <br />