Laserfiche WebLink
2 0 GROUNDWATER MONITORING, SAMPLING AND ANALYSIS <br /> On November 26, 2002, to comply with quarterly groundwater monitoring requirements, Ramage <br /> Environmental monitored and sampled the on-site monitoring wells <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 Free product (0 22 feet thick) was observed in MW-1 <br /> The depth to static groundwater across the site ranged from 47 44 feet below ground surface <br /> (bgs) in MW-3 to 48 45 feet bgs in MW-1 The corresponding groundwater surface elevation <br /> ranged from a high of 28 80 feet below mean sea level (msl) at MW-3 to a low of 29 24 feet below <br /> msl at MW-1 The resulting groundwater surface appears as a regular plane dipping to the west <br /> at a gradient of approximately 0 0041 foot/foot A groundwater surface contour map is included <br />' as Figure 5, and the groundwater monitoring data is summarized in Table 2 Between August 22 <br /> and November 26, 2002, the groundwater surface dropped an average of 1 08 feet, and the <br /> groundwater flow direction and gradient remained relatively constant <br /> 22 Groundwater Sampling and Analysis <br /> Following the groundwater level measurements, MW-2 and MW-3 were purged and sampled <br />' Due to the presence of free product, MW-1 was not sampled The wells (MW-2 and MW-3) were <br /> purged using a pump and dedicated disposable tubing, until at least three well casing volumes <br /> were extracted, and/or after groundwater temperature, pH and electrical conductivity values had <br />' stabilized Following well purging and recharge, groundwater was sampled from MW-2 and MW-3 <br /> using dedicated disposable bailers and laboratory-supplied containers Each sample container <br /> was transported in an iced cooler with chain-of-custody documentation to Excelchem <br /> Environmental Labs (Excelchem), a state of California certified hazardous waste testing laboratory <br /> (Certification #2119) <br /> Excelchem analyzed each of the groundwater samples for TPH-as-gasoline by EPA Method <br />' 8015M, and for benzene, toluene, ethylbenzene, xylenes (BTEX), MTBE, di-isopropyl ether <br /> (DIPE), ethyl tertiary butyl ether (ETBE), tertiary amyl methyl ether(TAME), tertiary butanol (TBA), <br /> 1,2-dichloroethane (1,2-DCA), and 1,2-dibromoethane (EDB) by EPA Method 8260B <br /> 6 <br />