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From: Scott [mai Ito:SBittingerCa stratusinc.net] <br /> Sent: Monday, May 04, 2015 4:29 PM <br /> To: Gabriel Gonzalez [EH] <br /> Subject: RE: 7835 Thornton / 1140 W. Hammer site - soil mass estimate <br /> With these mass estimates,you can give them to 100 different people and you will get 100 different answers. <br /> You could argue excluding the September 19, 1990 samples, because they are 'lateral limit' samples from the sidewalls <br /> of the excavation cavity. Adding in these numbers to the data end up 'diluting' the average TPHG/benzene <br /> concentrations downward, which reduces the mass removed calculation. <br /> Since SB-12 data isn't 'vertically biased' (ie samples collected in 5 foot intervals), you could argue using that using this <br /> data exclusively is the best way to go, and throwing out the other data. Using the SB-12 data exclusively could be done <br /> and you assume that all contamination is uniform across the excavation area, at each specific depth, but in reality,this <br /> probably isn't accurate either. <br /> I have highlighted the samples used on the attached table. Again, there is no 'correct answer' no matter how you <br /> calculate it. <br /> From: Gabriel Gonzalez [EH] [mai Ito:gagonzalez@sjcehd.com] <br /> Sent: Monday, May 04, 2015 3:57 PM <br /> To: Scott <br /> Subject: RE: 7835 Thornton / 1140 W. Hammer site - soil mass estimate <br /> Scott, may you please provide the specific sample IDs used in the calculations? Is there a reason for omitting the pre- <br /> excavation/pre-1990 soil boring data from borings advanced within the excavation area (e.g. SB-1 and SB-12)? <br /> Thanks, <br /> Gabriel <br /> From: Scott fmailto:SBittingerdstratusinc.net] <br /> Sent: Monday, May 04, 2015 3:26 PM <br /> To: Gabriel Gonzalez [EH] <br /> Subject: RE: 7835 Thornton / 1140 W. Hammer site - soil mass estimate <br /> There were 18 for benzene & 10 or so for GRO. They were the 1987 compliance soil samples, and 1990 tank bottom/ <br /> sidewall samples. Basically any sample that was not associated with drilling a soil boring or monitoring well. <br /> From: Gabriel Gonzalez [EH] [mailto:gagonzalez(aIsjcehd.com] <br /> Sent: Monday, May 04, 2015 3:24 PM <br /> To: Scott <br /> Subject: 7835 Thornton / 1140 W. Hammer site - soil mass estimate <br /> Hi Scott, <br /> Regarding Supplemental Information to Support Environmental Case Closure, what are the names/IDs of the 18 soil <br /> samples used to estimate the removed masses of GRO and benzene? <br /> CinrPraly <br />