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1 <br /> I5 0 Findings - - — -- - -- <br /> 5 9 Groundwater Level Measurements <br /> The elevation of groundwater in MW-1, MW-2, MW-3 and MW-4 was calculated by EI to be at <br /> r 21 87, 21 88, 2195 and 22 05 feet below mean sea level respectively on 09/30/03 <br /> Il <br /> El utilized the groundwater measurements to determine the direction of groundwater now and � <br /> the groundwater gradient present beneath the surface The groundwater flows easterly at a <br /> ` r gradient of 0 00155 ft/ft <br /> i The groundwater elevations have decreased approximately 2 1/2 feet since last quarter and <br />' approximately 5 feet since monitoring began in 1999 E <br /> Groundwater elevations are listed in Table 1, and shown graphically in Figure 4 <br />' 5 2 Groundwater Sample Analysis Results <br /> TPH-gasoline is no longer evident in MW-1, however, BTEX contamination reappeared MW- <br />' 1 continued to show TPH-diesel contamination at a level that was decreased slightly from the <br /> previous quarter MW-1 remains free of motor oil contamination <br /> MW-2 continued to show motor oil contamination as well as contamination from TPH-diesel <br /> and TPH-gasoline The contamination levels continue to decrease Motor oil contamination l <br /> continued to drop significantly, from 110,000 ppm in December 2001 to 4 4 ppm in the latest <br /> sampling Minor contamination from BTEX remains, as well as MTBE and DIPE <br /> MW-3 continues to remain free from contamination <br /> MW-4 showed a significant decrease in TPH-gasolme contamination as well as modest levels <br /> of BTEX and DIPS contamination MW-4 remains free of diesel or motor oil contamination <br />' All groundwater samples secured by El were logged in a chain-of-custody form, placed in an <br /> on-site refrigerator and picked up by a California Department of Health Services (DHS) <br /> certified laboratory for analysis for <br /> Total petroleum hydrocarbons as diesel, oil and gasoline (TPHg, TPHd and TPHo) by <br /> EPA Method_8015 <br /> I • Volatile aromatic compounds — benzene, toluene, ethyl benzene and total xylenes ! <br /> (BTEX)with Methyl tent-Butyl Ether(MTBE) by EPA Method <br /> e3 IW <br /> + Fuel oxygenated compounds — di-isopropyl ether (DIPS)� eth l-t-buhl ether (ETBE , <br /> tert-amyl methyl ether(TAME),t-butanol (TBA) by EPA Method 8260 <br /> 6 0 Floating Oil <br /> Floating oil has been removed from MW-2 periodically, starting in January 2000 A total of <br /> approximately 19 6 gallons of oil has been removed The results are summarized in Table 3 <br />