ARCHIVED REPORTS XR0006775 - Laserfiche WebLink

Home Browse Search

GROUND ZERO ANALYSIS,INC. - 2291 W March Lane,Suite 127D Stockton,California 95207 Telephone, (209)952-3481 Facsunde (209)952-9892 August 13, 1997 Mr Michael I nfurna San Joaquin County PHS/EHD P O Box 0388 Stockton, CA 95201-0388 Subject Annual 1997 Monitoring and Sampling Report Former Reeve's Exxon, 2360 East Street, Tracy, California Dear Mr Infurna • This letter report presents the results of the 1997 annual groundwater morutonng and sampling at the subject site (Figure 1) Site activities included measuring depth to water in the site wells, and purging and sampling groundwater for laboratory analysis The laboratory analysis was to include EPA method 8260 to analyze for the presence of several oxygenate compounds which include methanol, ethanol, tertiary butanol, methyl tert-butyl ether (MTBE), di-isopropyl ether (RIPE), ethyl tert-butyl ether (ETBE), and tertiary amyl methyl ether (TAME) Although most of these target analytes can be detected using this method, most laboratories have not included these standards in their current 8260 analysis The required modifications to include these analytes in the EPA 8260 scan (obtain standards, recalibrate) could not be completed within the sample hold times As a result, groundwater samples e not analyzed using EPA method 8260 In addition, most laboratories indicated that the methanol and ethano cou no a accurately quantified using the 8260 analysts Groundwater monitoring was conducted on July 24, 1997 on wells MW1, MW2, and MW3 The groundwater elevations across the site fell an average of 0 15 feet since the last monitoring event on October 7, 1996 Figure 2 depicts the groundwater flow direction and hydraulic gradient on July 24, 1997 Flow direction at the site was generally to the northeast at a gradient of approximately 0 005 ft/ft Monitoring data are summarized in Table 1 Monitoring data sheets are included in Attachment A- On July 24, 1997 after purging at least three casing volumes of groundwater and stabilization of temperature, pI-L and electrical conductivity, samples were collected from each well in accordance with the site Well Sampling Protocol Samples were analyzed by Argon Laboratories (ELAP #1873) of • Modesto, California for benzene, toluene, ethylbenzene, xylenes (BTEX), and MTBE using EPA pestana 036\umua197 doc