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2 0 GROUNDWATER MONITORING, SAMPLING AND ANALYSIS <br /> On March 29, 2002, Ramage Environmental monitored and sampled the monitoring well network <br /> 21 Groundwater Monitoring <br /> Upon arrival at the site, each of the wellheads was inspected, unlocked and opened Depth-to- <br /> groundwater was measured in each of the wells using a water level indicator capable of <br /> measuring groundwater to within 0 01 foot A sheen of separate-phase hydrocarbons (i e , free <br /> product) was observed in MW-1 <br /> The depth to static groundwater across the site ranged from 44 31 feet bgs in MW-2 to 44 94 feet <br /> bgs in MW-1 The corresponding groundwater surface elevation ranged from a high of 24 86 feet <br /> below mean sea level (msl) at MW-2 to a low of 25 89 feet below msl at MW-3 The resulting <br /> groundwater surface appears as a regular plane dipping to the northwest at a gradient of <br /> approximately 0 015 foot/foot A groundwater surface contour map is included as Figure 3 The <br /> well construction details and groundwater monitoring data are summarized in Table 1 <br /> 22 Groundwater Sampling and Analysis <br /> Following the groundwater level measurements, all three wells were purged and sampled The <br /> wells were purged using a pump and dedicated disposable tubing, until at least three well casing <br /> volumes were extracted, and/or after groundwater temperature, pH and electrical conductivity <br /> values had stabilized Following well purging and recharge, groundwater was sampled from the <br /> wells using dedicated disposable bailers and laboratory-supplied containers Each sample <br /> container was labeled, packaged in an iced cooler and transported with chain-of-custody <br /> documentation to Kiff Analytical, E_bC (Kiff), a state of California certified hazardous waste testing <br /> laboratory (Certification #2236) Kiff analyzed each of the groundwater samples for TPH-as- <br /> gasoline, BTEX, MTBE, di-isopropyl ether(DIPE), ethyl tertiary butyl ether (ETBE), tertiary amyl <br /> methyl ether (TAME), tertiary butanol (TBA), and 1,2-dichloroethane (1,2-DCA) by EPA Method <br /> 8260B <br /> The groundwater samples collected from all three wells contained detectable concentrations of <br /> TPH-as-gasoline and BTEX compounds MTBE was detected in MW-1 at 34,000 micrograms per <br /> liter (pg/l) and in MW-2 at 9,900 pg/l MTBE was not detected in MW-3 The groundwater sample <br /> results are summarized in Table 2 and the laboratory reports are included as Appendix A <br /> 5 <br />