ARCHIVED REPORTS_XR0003236 - Laserfiche WebLink

Home Browse Search

. 2 0 GROUNDWATER MONITORING, SAMPLING AND ANALYSIS On May 9, 2003, to comply with quarterly groundwater monitoring requirements, Ramage Environmental monitored and sampled the four wells 21 Groundwater Monitoring Depth-to-groundwater was monitored using a water level indicator capable of measurements to within 0 01 foot The static depth to the groundwater table, as measured in the four groundwater monitoring wells, ranged from 23 53 feet bgs in MW-1 to 24 58 feet bgs in MW-3 The groundwater surface elevation in the four wells ranged from a high of 12 40 feet below mean sea level (msl) at MW-1 to a low of 13 01 feet below msl at MW-4 The resulting groundwater surface appears as an irregular plane dipping to the east-southeast at a gradient of approximately 0 018 foot/foot A groundwater surface contour map is included as Figure 4, and the groundwater monitoring data are summarized in Table 3 M2.2 Groundwater Sampling and Analysis Fallowing groundwater level measurements, the wells were purged and sampled The wells were purged with a pump and dedicated disposable tubing until at least three well casing volumes had been removed and/or after groundwater temperature, pH and electrical conductivity values had stabilized Groundwater was sampled from the wells using disposable polyethylene bailers and laboratory-supplied containers Each 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 samples for TPH-as-motor ail, TPH-as-diesel, TPH-as-kerosene, TPH-as-gasoline and BTEX by EPA Method 8020/8015M, and for MTBE, di-isopropyl ether(DIPE), ethyl tertiary butyl ether(ETBE), tertiary amyl methyl ether (TAME), tertiary butanol (TBA), and 1,2- ' dichloroethane (1,2-DCA) by EPA Method 8260B The groundwater samples collected from MW-1, MW-2 and MW-3 contained detectable concentrations of petroleum hydrocarbons, including TPH-as-gasoline, TPH-as-kerosene, and BTEX compounds The groundwater sample collected from MW-4 was free of petroleum hydrocarbons MTBE was not detected in any of the four groundwater samples The groundwater sample analytical results are summarized in Table 2, the distribution of gasoline and benzene in groundwater is shown on Figure 5, and the laboratory reports are included in Appendix A 6