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1 _ <br /> GROUND ZERO ANALYSIS, INC. <br /> h <br /> 1714 Main Street <br /> ftcalon, California 95320 <br /> Telephone: (209) 838-9888 <br /> Fwsnnlle: (209)838-9883 <br /> July 27, 1998 <br /> Mr Harlin Knoll <br /> San Joaquin County Public Health Services <br /> Environmental Health Division <br /> 304 East Weber Avenue, Third Floor <br /> Stockton, CA 95202 <br /> Subject Second Quarter 1998 Site Status Report <br /> Knowles Property <br /> 1140 W Hammer Lane, Stockton, California <br /> Dear Mr Knoll <br /> r <br /> This letter report summarizes second quarter 1998 activities at the subject site (Figure 1) Activities <br /> during the quarter included monitoring depth to water in all site wells, purging and sampling wells <br /> t MW 1, MW4, MW5, and MW8, and analyzing samples for total petroleum hydrocarbons as gasoline <br /> (TPHG), and benzene, toluene, ethylbenzene, total xylenes(BTEX) <br /> GROUNDWATER MONITORING <br /> Groundwater monitoring was performed on May 19, 1998 The depth to groundwater beneath the site <br /> ranged from 32 43 to 34 61 feet below grade Overall, groundwater elevations rose an average of 3 17 <br /> feet since February 13, 1998 and 5 76 feet since May 1997 The water table beneath the site hes above <br /> the tops of the screened intervals in wells MW4 through MW8 The water table is within the screened <br /> interval in well MW3 and at the tops of the screened intervals in wells MW1 and MW2 The <br /> groundwater flow direction at the time of measurement was generally to the southeast A groundwater <br /> gradient map for May 19, 1998 is presented on Figure 2 Groundwater monitoring data are <br /> summarized in Table 1 <br /> GROUNDWATER SAMPLING AND ANALYSIS <br /> Monitoring wells MW 1, MW4, MW5, and MW8 were purged and sampled May 19, 1998 All purge <br /> water was contained on site in labeled drums approved by the Department of Transportation for <br /> storage of hquid waste Well purge logs are included in Attachment A Groundwater samples were <br /> submitted to Argon Laboratories (FLAP #1873) and analyzed for TPHG and BTEX using EPA <br /> methods 8015 modified and 8020, respectively Analyses for oxygenate compounds were discontinued <br /> ob <br /> based on historical results below accepted action levels(Table 3) <br /> groundzelknowles hamlreport0gm 1998 doe <br />