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Stantec +//` Page 2 of 4 <br /> .K � U, <br /> 1 <br /> Sent: Tuesday, January 19, 2010 3:57 PM <br /> To: Chevlen, Benjamin <br /> Subject: RE: Path forward at 76 Station 5886 in Stockton <br /> The EHD appreciates the intention. <br /> Batch gw extraction has it's pros and cons. I saw the Batch Extraction Work Plan <br /> dated December 10...1 see no comment from Margaret..Did you get some EHD <br /> comment on it I'm not aware of yet? are you waiting for a reply? <br /> i a soil vapor intrusion evaluation is required for all UST sites in LOP before a NFA <br /> consideration can be reviewed. Good plan to get this out of the way. get me a <br /> proposal/upload to GT. <br /> as for offsite MW cluster install beyond the building/problem access area, well, I <br /> have my doubts stepping out another 250' to 400' will do any good. but if you can <br /> support it with a technical justification, send it on to me in a proposal/work plan <br /> format. <br /> I keep remembering what Margaret told me about this site before she left..."just a <br /> boring or two beyond MW-9 to prove the extents...........it all seemed so simple then.. <br /> t <br /> I'm trying to research this site, but time for other priorities has me pinned against the <br /> NFA/ well destruction wall.. <br /> 1 looked at the "Results of HydrogeologicModeling dated Jan 7. I'm not aware of <br /> any datum points (borings, soil or gw samples IN March lane...are there any?), so <br /> I"m having difficulty understanding the data now. <br /> Nuel is swamped also. I have tried to set up a devote time to discuss it with him. so <br /> far, no luck. <br /> as it stands now, MW-9D is the hottest MtBE well for the site. I"m not sure how it <br /> got there. I'm looking fora cross section (NE to SW)that goes from MW-2, thru <br /> MW-1 and out to MW-9...1 can't find one yet. any advise on where to look for it? <br /> I would of like to seen Feb 2002 MtBE data for MW-1 as the starting point for your <br /> Hydrogeological model. MtBE concentrations in MW-1 at the time, 6,300 ug/I then <br /> quickly down to 3,400 and hovering around 5000 for some months could have <br /> proven a point I'm thinking may need addressing. With another quick drop in MtBE <br /> in MW-1 to the mid 2000 ug/I in 2003 and then 400-500 ug/I for 2004. Down to <br /> double digits in 2006 and single digits in 2007 is a pattern that could help <br /> understand the speed of the migration better and maybe prove a point/technical <br /> justification why NO wells needed 250-400 feet further on. <br /> I'm concerned that how MW-9D didn't start to show concern until 2007. Then an <br /> increasing trend since...but at a significant lower concentration, but only a ceiling of <br /> 150 ug/I as your model suggest? <br /> but if +6000 ug/1 MtBE onsite in 2002 moved (and dropped?) +250 feet and.is <br /> impacting a well to only 150-150 ug/I after 5 years, can't you calculate what it would <br /> 1/21/2010 <br />