Qua rly Groundwater Monitoring Report
<br /> Former E-Z Serve Location 100966
<br /> 2537 Waterloo Road
<br /> Stockton,California
<br /> • Delta Project No "MSO-966
<br /> Page 2
<br /> 20 GROUNDWATER MONITORING DATA
<br /> 21 Groundwater Gauging and Sampling
<br /> Delta Environmental Consultants, Inc (Delta) performed groundwater monitoring activities at this site on
<br /> February 16, 2005 Prior to purging, the monitoring wells were gauged for liquid phase hydrocarbons
<br /> (LPH) and depth to water utilizing an oil water interface probe Groundwater ranged from 56 05 feet to
<br /> 56 68 feet below top of casing No LPH was detected in any of the monitoring wells during the February
<br /> 16, 2005 gauging activities Depths to groundwater and groundwater elevations are presented in Table 1,
<br /> Groundwater Analytical Data
<br /> Prior to sampling, the monitoring wells were purged by removing approximately three well volumes of
<br /> water Monitoring wells were purged utilizing a submersible pump Once the wells had been purged,
<br /> they were sampled utilizing disposable polyurethane bailers The groundwater samples collected were
<br /> decanted into properly labeled, laboratory prepared sample containers and placed on ice for storage prior
<br /> to transporting to the laboratory The samples were transported, under strict chain-of-custody protocols,
<br /> to KiffAnalytical LLC of Davis, California, for analysis of benzene, toluene, ethyl-benzene, total xylenes
<br /> • (BTEX), total petroleum hydrocarbons (TPH) in the gasoline range, methyl tert butyl ether (MTBE),
<br /> diisopropyl ether(DIPE), ethyl tert butyl ether(ETBE), tert-amyl methyl ether(TAME), tert butyl alcohol
<br /> (TBA), methanol, ethanol, 1,2-Dichloroethane, and 1,2-Dibromoethane by EPA Method 8260B
<br /> 2.2 Analytical Data
<br /> Laboratory chemical analysis of the groundwater samples collected on February 16, 2005 indicates that
<br /> benzene concentrations have remained below laboratory reporting limits in monitoring wells MW-1,
<br /> MW-2, MW-4, MW-5, MW-6, MW-8, MW-13, MW-15, MW-16 and MW-17, have decreased in
<br /> monitoring wells SVE-2 and EX-1, and have increased in monitoring well SVE-1 and SVE-3 The
<br /> highest benzene concentration was 5,700 µg/L in monitoring well SVE-1 MTBE concentrations were
<br /> below laboratory reporting limits in monitoring wells MW3, MW-4, MW-5, MW-7, MW-8, MW-15 and
<br /> MW-17 Levels of MTBE have decreased in monitoring wells MW-2, MW-4, MW-6, MW-7, MW-9,
<br /> MW-10, MW-11, MW-12, MW-13, MW-14, MW-16, SVE-1, SVE-2, SVE-3, and have increased in
<br /> monitoring well EX-1 The highest MTBE concentration was 190 gg/L in monitoring well EX-1
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