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Ms Vicky McCartney Page 2 • Samples were collected after parameter stabilization, and a minimum of 80% water level recovery Purge water was contained in properly labeled DOT-approved 55-gallon drums The drums are currently being stored onsite Purge logs are included in Attachment A Groundwater samples were delivered under chain of custody protocol to Argon Laboratories (ELAP #2359) Analysis consisted of TPHg using modified EPA method 8015B, and BTEX using EPA method 8021B Per the March 22, 2000 letter from San Joaquin County Environmental Health Department, groundwater samples were not analyzed for fuel oxygenates Monitoring Well Surveying As required by AB 2886, all monitoring wells were surveyed by a Registered Surveyor to a horizontal accuracy of less than one meter and a vertical accuracy of 0 01 feet On February 5, 2004, Morrow Surveying surveyed the latitude and longitude of the site wells relative to the North American Datum (NAD 83) Wellhead elevations were surveyed relative to the North American Vertical Datum (NAVD 88) A site map showing monitoring well locations, latitude and longitude coordinates and wellhead elevations is included in Attachment B Groundwater Analytical Results Toluene, ethylbenzene and xylenes were not detected above laboratory method detection limits (MDLs) in any site wells TPHg was not detected in wells MW2 and MW3 TPHg was detected in well MW1 at a concentration of 120 parts per billion (ppb) Benzene was detected in wells MWI. through MW3 at concentrations of 20 ppb, 1 2 ppb and 150 ppb, respectively Analytical results are summarized in Table 2 Attachment C contains laboratory reports and chain of custody documentation Graphs of TPHg and benzene over time are included in Attachment D Summary • Groundwater levels at the site fell since last monitored in July 2002 These are the lowest water table elevations measured since October 1998 The average groundwater gradient across the site was 0 008 ft/ft Groundwater flowed predominantly in a northeasterly direction, which is consistent with previous measurements • Toluene, ethylbenzene and xylenes were not detected above MDLs in any site well TPHg concentrations were less than N�H�s ip wells MW2 and MW3 'A rVjj e • Relative to the previous sampling event (July 2002), TPHg in well MW3 decreased (it should be noted, however, that the TPHg quantitation for the sample from well MW3 did not include benzene) Benzene in well MW1 decreased Benzene to well MW3 increased and benzene in well MW2 is near MDLs 11GZA FSIVOE IIDATAIGROUNDZEIW-EISARIISAR2004 doc