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S EcC ® R <br /> • Mr Harlin Knoll <br /> March 27, 2006 <br /> Page 2 <br /> REPORT OF FINDINGS <br /> On January 25, 2006, G-R performed 1Q2006 groundwater monitoring and sampling <br /> (Attachment A) Monitoring well samples collected by G-R were analyzed by a suite of <br /> analytical methods chosen to assess the presence of total petroleum hydrocarbons as <br /> diesel (TPHd), total petroleum hydrocarbons as gasoline (TPHg), benzene, toluene, <br /> ethylbenzene, and total xylenes (BTEX), and methyl tertiary butyl ether (MtBE) Whenever <br /> possible, detection limits for all analyses, with the exception of TPHg, have been 0 5 <br /> micrograms per liter (rrg/L) Sporadically the detection limits were raised due to the <br /> presence of elevated concentrations of TPHg Typically detection limits for TPHg are 50 <br /> /rg/L <br /> G-R's standard operating procedures (SOPs) indicate that before sampling, each well is <br /> checked for the presence of separate-phase petroleum hydrocarbons If separate-phase <br /> petroleum hydrocarbons are not detected, then the depth to water and the total depth of <br /> each well is measured and recorded prior to sampling Groundwater elevations are <br /> calculated using the measured depths Groundwater elevation across the site ranged from <br /> 8 15 to 8 58 feet above mean sea level (msl) Groundwater elevations across the site <br /> . decreased an average of 0 42 feet from the previous sampling event The potential for <br /> groundwater flow was calculated to the northeast at an approximate gradient of 0 002 to <br /> 0 004 <br /> c <br /> A summary of TPHd, TPHg, BTEX, and MtBE laboratory analytical data are presented <br /> below { <br /> ANALYTICAL METHODS ' <br /> Groundwater samples from MW-1, MW-2, MW-3, and MW-4 were analyzed using the a <br /> following parameters, <br /> • BTEX and MtBE by EPA Method 8260B, <br /> • TPHd as TPH-DRO by CA LUFT modified EPA Method 8015B, and, <br /> • TPHg as TPH-GRO by CA LOFT modified EPA Method 8015B <br /> RESULTS <br /> Laboratory analytical results are summarized in Tables 1 through 2 These tables <br /> represent a summary of data tables presented in the G-R report included as Attachment A <br /> . No petroleum hydrocarbon constituents were reported in the certified laboratory analytical s <br /> reports for groundwater samples collected from monitoring wells MWA and MW-2 <br /> N\Files\Projects\Chevron\Retajll#9-82641Penodic Monitonng1200611Q2006_QMR doc <br />