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Page 1 of 2 <br /> 1%W <br /> Lori Duncan [EH] <br /> From: Fortner, Thomas [Thomas.Fortner@WestonSolutions.com] <br /> Sent: Friday, July 25, 2008 1:06 PM <br /> To: Lori Duncan [EH] <br /> Cc: Ellen Aquaro [CAO]; Craig Ogata [FMCP] <br /> Subject: RE: Human Services Agency MW-8 destruction <br /> Attachments: Unknown semi-VOCs.PDF; Unknown VOCs.PDF <br /> Hi Lori, <br /> The unknown hydrocarbon in the diesel range is very suspect. It appears in all of the wells sampled except MW-2. <br /> Our chemist says that it is not a fuel related contaminant and can be identified by semi-volatile analyses by EPA <br /> method 8270. The concentration of the unknown hydrocarbon appears to be greatest in MW-8 with lesser <br /> concentrations in wells MW-7 and MW-6 which are down gradient of the former gas station. <br /> The unknown hydrocarbon may be a cross-contaminant from the purge pump used for the low flow sampling as it <br /> doesn't appear in well MW-2 which is sampled by a bailer. I will collect an equipment blank sample from the pump <br /> and analyze it for TPH-diesel in addition to TPH-gas/BTEX during the next quarterly sampling event to confirm if <br /> this contaminant is truly in the groundwater. <br /> The same unknown VOC in the gasoline range detected in well MW-8 was also detected in MW-5 (up-gradient of <br /> MW-8)in January 2007 and is also not a fuel related contaminant. The unknown VOC could be identified by a full <br /> VOC analysis by EPA Method 8260. The detection of the unknown VOC in both MW-8 and MW-5 appears to be <br /> from an off-site source and not associated with the former USTs at the Human Services Agency. I don't think it's <br /> the Human Services Agency's responsibility to monitor an unknown groundwater plume from an up-gradient <br /> source. <br /> Attached are the chromatograms from the July sampling and the chromatogram for MW-5 from June 2007. <br /> Hope you have a nice weekend, <br /> Tom <br /> From: Lori Duncan [EH] [mailto:lduncan@sjcehd.com] <br /> Sent: Monday, July 21, 2008 4:27 PM <br /> To: Fortner, Thomas <br /> Subject: RE: Human Services Agency MW-8 destruction <br /> Hi Tom, <br /> I discussed this with my supervisor and she requested that you not destroy the well. The Regional Board may <br /> question destruction of thie well when it come times for closure. The lab report noted the diesel detection as not <br /> resembling the standard, but made the same notation on the other samples on the same page. It is something <br /> that will be questioned, and will need a more detailed technical justification to be written off. <br /> In light of the potential new tanks, I think we should keep this well for now, and put it on the modifided sampling <br /> routine. <br /> Thanks, <br /> Lori <br /> From: Fortner, Thomas [mailto:Thomas.Fortner@WestonSolutions.com] <br /> 7/29/2008 <br />