Laserfiche WebLink
1 <br />' 5 0 Findings <br /> s � <br />' 51 Groundwater Level Measurements <br /> The elevation of groundwater in MWA, MW-2, MW-3 and MW-4 was calculated by El to be at <br /> 19 38, 19 28, 19 45 and 19 54 feet:below mean sea level respectively on 06/21/03 <br />' EI utilized the groundwater measurements to determine the direction of groundwater flow and <br /> the groundwater gradient present beneath the surface The groundwater flowOrUferly at a 3 t4 <br /> gradient <br />' gradient of 0 02 ft/ft 1� 31 <br /> The groundwater elevations decreased approximately 1 foot in MWA and MW-4 from <br />' September 2002 to July 2003,and remained constant in MW-2 and MW-3 <br /> Groundwater elevations are listed in Table 1,and shown graphically in Figure 4 <br />' 5.2 Groundwater Sample Analysis Results <br /> The groundwater was sampled on 06/21/03 MW-I co ntin�ied to show TPH-gasoline and TPH- <br /> diesel contamination The level of TPH-gasohne andTon amination 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, however, levels have significantly decreased Minor contamination from <br /> BTEX remains, as well as MTBE and DIPE Motor oil contamination continued to drop <br /> Isignificantly, from 110,000 ppm in December 2001 to 5 02 ppm in the latest sampling <br /> MW-3 continues to remain free from contamination ell <br />' MW-4 showed modest levels of TPH-gasoline, BTEX and DIPE contamination, and no diesel <br /> or motor oil contamination <br />' All groundwater samples secured by EI 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 /> I • Total petroleum hydrocarbons as diesel, oil and gasoline (TPHg, TPHd and TPHo) by <br /> EPA Method 8015 <br /> • Volatile aromatic compounds — benzene, toluene, ethyl benzene and total xylenes <br /> (BTEX)with Methyl tert-Butyl Ether(MTBE)by EPA Method 020 4 m o+� <br /> • Fuel oxygenated compounds — di-isopropyl ether (DIPE), ethyl-t-butyl ether (ETBE), <br /> tert-amyl methyl ether(TAME),t-butanol (TBA)by EPA Method 8260 <br /> I6.0 Floating Oil <br /> Floating oil has been removed from MW-2 periodically, starting in January 2000 A total of <br /> approximately 19 1 gallons of oil has been removed The results are summarized in Table 3 <br /> 5 <br />