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f <br /> Chevron Pipeline Co.,Dividend Property -3- 7 March 1996 <br /> Additional Ground Water Monitoring <br /> In our 1 February letter, we requested that the discharger submit a time schedule by 29 February <br /> for additional ground water monitoring. We requested a minimum of two quarters of monitoring <br /> of wells downgradient from MW-13 during the fust two quarters of 1996. Geomatrix' responded <br /> that the subject of further ground water monitoring would be discussed at our 7 March meeting. <br /> The deadline for submittal of the time schedule has passed. Further delays could result in failure <br /> to monitor the wells during the first quarter of 1996, when ground water levels are expected to be <br /> the highest. <br /> Analytical Chromatograms Contained in Geomatrix'26 October 1995 Report <br /> In reviewing this case with Gordon Lee Boggs for consistency with similar cases in our <br /> Underground Tank Program, Gordon asked whether chromatograms had been submitted to <br /> demonstrate the range of hydrocarbons present in ground water at the site. We reviewed the <br /> chromatograms contained in Geomatrix' 26 October 1995 Quarterly Groundwater Monitoring <br /> Report. I also reviewed the chromatograms with our chemist Ms. Hoe. Contained in the report <br /> are chromatograms for GC analyses of a crude oil standard and water samples taken from the two <br /> wells with greatest impact, MW-13 and MW-23. The following observations can be made from <br /> these chromatograms: <br /> a) The extent of the crude oil standard peak is much greater in slower-eluting (longer-chain) <br /> constituents than the pollutants contained in the water samples. The crude oil standard <br /> contains significant constituents through the 11-minute retention time, while the analyte <br /> peaks in ground water samples tend to drop off at about 7 or 8 minutes. This indicates that <br /> the mix of constituents in the standard does not match that of the ground water samples. If <br /> the area under the entire crude oil standard peak was used to estimate the concentration of <br /> pollutants in the ground water samples, significant errors would result. <br /> b) There is inadequate separation between the initial solvent peak and the hydrocarbon analyte <br /> peaks in many of the chromatograms. The valley between these peaks does not approach <br /> baseline. This can lead to further errors in calculating analyte concentrations in the samples. <br /> Ms. Hoe suggested that the oven temperature program be adjusted downward to cause <br /> greater separation between the initial solvent peak and the analyte peaks. <br /> c) The width of the initial solvent peak in the chromatograms for samples identified as "MW- <br /> 23" and "MW-23F" indicate that significant carryover occurred from the previous <br /> chromatographic runs. Again, this can lead to errors in concentration estimation for these <br /> samples. <br /> All future analytical work done on samples from this site should correct these problems. <br /> 6 March 1996 Voice-Mail Messages from Ms. Zemo of Geomatrix <br /> In her initial voice-mail message to you, Ms. Zemo requested that Mr. Pinkos be present at today's <br /> meeting and, if he could not be present, that the meeting be rescheduled. In a later message, the <br /> consultant indicated that she was asking Mr. Pinkos to be present because my review of this site <br /> was relying on taste and odor thresholds that were inappropriate in Chevron's view and Geomatrix <br />