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LA 2.0 GROUNDWATER MONITORING, SAMPLING AND ANALYSIS �+ On June 30, 2008, to comply with quarterly groundwater monitoring requirements, Ramage Environmental monitored and sampled the three wells. 2.1 Groundwater Monitoring To calculate the groundwater gradient and flow direction, Ramage Environmental measured depth-to-groundwater in all three wells using a water level indicator. The depth-to-groundwater beneath the site ranged from 8.67 feet bgs in MW-3 to 9.14 feet bgs in MW-1. The groundwater elevation beneath the site ranged from a high of 40.24 feet above mean sea level (msl) in MW-1 to a low of 40.10 feet above msl in MW-3. The resulting groundwater surface appears as a regular plane dipping toward the north-northwest at a gradient of approximately 0.0022 foot/foot. A groundwater surface contour map is included as Figure 3, and the groundwater monitoring data are summarized in Table 2. Between March 21, and June 30, 2008, the groundwater elevation in the three monitoring wells dropped an average of 0.38 feet, the gradient decreased from 0.0029 to 0.0022 foot/foot, and the groundwater flow direction remained toward the north. These groundwater surface characteristics are consistent with historical and seasonal trends. r ; 2.2 Groundwater Sampling and Analysis Following groundwater level measurements, Ramage Environmental purged and sampled all three monitoring wells. The wells were purged using a pump and dedicated disposable tubing, until at least three well casing volumes were extracted and/or after groundwater temperature,'pH and electrical conductivity values had stabilized. The sampling information field sheets are I— 1cluded in Appendix A. i 51lowing well purging and recharge, Ramage Environmental sampled groundwater from the ►IIs using dedicated disposable bailers and laboratory-supplied containers. The groundwater • ; apples were transported in an iced cooler with chain-of-custody documentation to Excelchem iironmental Labs (Excelchem), a state of California certified hazardous waste testing �._ $ratory (Certification #2119). Excelchem analyzed each of the groundwater samples for iT i-as-diesel by EPA Method 8015M, TPH-as-gasoline, and BTEX by EPA Method 1B/8015M, and for methyl tertiary butyl ether(MTBE), di-isopropyl ether (DIPE), tertiary butyl ?tl '(ETBE), tertiary amyl methyl ether(TAME), tertiary butanol (TBA), 1,2-dichloroethane (1,2- and 1,2-dibromoethane (EDB) by EPA Method 82606. 6