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• 2.0 GROUNDWATER MONITORING, SAMPLING AND ANALYSIS On March 7, 2003, to comply with quarterly groundwater monitoring requirements, Ramage Environmental monitored and sampled the on-site monitoring wells in addition, Ramage Environmental installed a passive skimmer in MW-1 and initiated weekly free product removal 2.1 Groundwater Monitoring Upon arrival at the site, each of the wellheads was inspected, unlocked and opened Depth-to- groundwater was measured in each of the wells using a water level indicator capable of measuring groundwater to within 0 01 foot Free product (0 45 feet thick) was observed in MW-1 The depth to static groundwater across the site ranged from 46 33 feet bgs in MW-3 to 47 17 feet bgs in MW-2 The corresponding groundwater surface elevation ranged from a high of 27 69 feet below mean sea level (rnsl) at MW-3 to a low of 27 94 feet below msl at MW-1 The resulting ' groundwater surface appears as a regular plane dipping to the west-southwest at a gradient of approximately 0 0020 foottfoot A groundwater surface contour map is included as Figure 4 The well construction details and groundwater monitoring data are summarized in Table 1 2.2 Groundwater Sampling and Analysis ysrs Following the groundwater level measurements, MW-2 and MW-3 were purged and sampled Due to the presence of free product, MW-1 was not sampled The wells (MW-2 and MW-3) 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 Following well purging and recharge, groundwater was sampled from MW-2 and MW-3 using dedicated disposable bailers and laboratory-supplied containers rEach sample container was transported in an iced cooler with chain-of-custody documentation to Excelchem Environmental Labs (Excelchem), a state of California certified hazardous waste testing laboratory (Certification #2119) Excelchem analyzed each of the groundwater samples for TPH-as-gasoline and BTEX by EPA Method 802018015M, and for methyl tertiary butyl ether (MTBE), di-isopropyl ether (DIPS), ethyl tertiary butyl ether(ETBE), tertiary amyl methyl ether ' (TAME), and tertiary butanol (TBA) by EPA Method 8260B 5