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Status Report <br /> ARCO Facility No 6100 <br /> Tracy, Caldomia <br /> Page 5 <br /> Water Supply Well <br /> A Delta technician collected a water sample from the onsite water supply on February 7, <br /> 2001 The sample was collected from a sample port located at the surface of the <br /> wellhead The groundwater sample was submitted to Sequoia and analyzed for total <br /> petroleum hydrocarbons as gasoline (TPHG), benzene, toluene, ethylbenzene, and total <br /> xylenes (BTEX) using USEPA Method 8015/8020 DHS LUFT and for methyl tertiary <br /> butyl ether (MTBE), ethyl tertiary butyl ether (ETBE), tertiary butyl alcohol (TBA), <br /> di-isopropyl ether (DIPE), and tertiary amyl methyl ether (TAME) using USEPA Method <br /> 8260A The sample collected from the water supply well was additionally analyzed for <br /> nitrate (as NO3) using USEPA Method 300 0 and for fecal coliform using USEPA <br /> Method SM 9221 All constituents analyzed were reported below method detection limit <br /> with the exception of nitrate, which was reported at 16 mg/L <br /> Monitoring Well MW-1 <br /> In an attempt to determine if oxygenates, specifically MTBE, are present in the floating <br /> product found in MW-1, a sample of the floating product was added to a clean water <br /> sample and analyzed On February 7, 2001, while removing the floating product from <br /> . the well and prior to developing the well, Delta retained a small sample from the removed <br /> product Using a disposable eyedropper, approximately two droplets of the product were <br /> added to a clean 40-milliter VOA that was filled with de-ionized water The sample was <br /> sealed, labeled and forwarded to Sequoia for chemical analyses The sample was <br /> analyzed for BTEX using USEPA Method 8015/8020 DHS LUFT and MTBE, ETBE, <br /> TBA, DIPE, and TAME using USEPA Method 8260A The sample was also analyzed <br /> for nitrate (as NO3) using USEPA Method 300 0 and for fecal coliform using USEPA <br /> Method SM 9221 Oxygenates were reported below the method detection limit and <br /> BTEX constituents were reported at concentrations ranging from 4,000 to 36,000 µg/L <br /> On February 8, 2001, following development of MW-1 and monitoring the recharge to <br /> 70% recovery, a Delta technician collected a water sample The sample was submitted to <br /> Sequoia and analyzed for TPHG, benzene, toluene, ethylbenzene, and total xylenes <br /> (BTEX) using USEPA Method 8015/8020 DHS LUFT and MTBE, ETBE, TBA, DIPE, <br /> and TAME using USEPA Method 8260A Petroleum hydrocarbons were detected in the <br /> sample at high concentrations Concentrations of MTBE and TBA were reported at 10 6 <br /> and 245 µg/1, respectively <br /> Selected Vapor Extraction Wells <br /> A Delta technician purged the water present in vapor extraction wells VW-2 through <br /> VW-6 on February 7, 2001 Since the recharge rates were extremely slow, the wells were <br /> . not sampled until the following day, February 8, 2001 Table 3 presents the depth to <br /> groundwater and volume of water purged from each vapor extraction well sampled <br />