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_v A total of six groundwater monitoring wells are used to monitor groundwater quality below the <br /> site Groundwater samples were collected by WGR from six groundwater monitoring wells <br /> (MW3-1, MW3-2, MW3-3, MW34, MW3-5, and MW3-6) On December 17, 2004, monitoring <br /> wells MW3-1, MW3-2, MW3-3, MW3-4, MW3-5, and MW3-6 (Figure 2) were purged and <br /> sampled in that order by WGR Depth to groundwater was measured in the site monitoring wells <br /> before purging Prior to sampling each well, the presence of separate-phase petroleum <br />] hydrocarbon was assessed with a disposable bailer Groundwater was purged from each well <br /> using dedicated submersible pumps Each dedicated submersible pump is uniquely identified for <br /> use in the same well each quarter and is stored on site <br /> Each well was purged of at least three well volumes Field parameters were measured after <br /> purging approximately each well volume Field parameters consisted of electrical conductivity, <br /> pH, temperature, dissolved oxygen, and oxidation reduction potential and were recorded on field <br />] data sheets (Appendix A) After purging was complete and the dedicated pumps were removed <br /> from the monitoring wells, new clean disposable bailers were used to collect groundwater <br /> samples from the monitoring wells The groundwater samples were transferred from the bailers <br /> into sample containers The samples were collected for laboratory analysis of total petroleum <br /> hydrocarbons quantified as gasoline (TPHg) and benzene, toluene, ethylbenzene, and xylenes <br /> (BTEX) <br />] Groundwater samples collected by WGR were preserved and transported under chain-of-custody <br /> (Appendix B) procedures to McCampbell Analytical, Inc (MAI), in Pacheco, California, a <br /> state-certified laboratory The groundwater samples were analyzed by MAI for TPHg and BTEX <br /> using U S Environmental Protection Agency(EPA) methods SW8015Cm and SW8260B, <br /> respectively <br /> 3.0 MONITORING RESULTS <br /> Fourth quarter 2004 WGR monitoring results are discussed in the following sections <br /> 3.1 GROUNDWATER ELEVATION, FLOW DIRECTION,AND GRADIENTS <br /> Groundwater elevation data from December 17, 2004 (Table 1), were used to construct <br /> potentiometnc contours on Figure 3 No separate-phase petroleum hydrocarbons were reported <br /> in the site wells Groundwater levels have risen 0 68 to 0 82 feet in the site monitoring wells <br /> since third quarter 2004 <br />