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i <br /> Koschel, Dana <br /> From: Kristin Shelton [Kshelton@waterboards.ca.gov] <br /> Sent: Wednesday, June 09, 2010 8:45 AM <br /> To: Koschel, Dana <br /> Cc: Just, Allen; John (JohnMacleod) Macleod <br /> Subject: Re: Corral Hollow and Grant Line Roads, Tracy-proposed site assessment <br /> Attachments: Kristin Shelton.vcf <br /> Kristin Sheltonxcf <br /> (726 B) <br /> Dana - <br /> I have looked at the tables with the recent data for HB-1 and HB-3 . Soil concentrations <br /> were below laboratory detection limits in these borings and there is minimal groundwater <br /> contamination. The concern is that concentrations in MW-6 are not decreasing and it is <br /> not clear whether the groundwater will reach WQOs within a reasonable timeframe. I would <br /> like to see the data from the remaining two soil borings so we can assess the source of <br /> the continued groundwater concentrations in MW-6. Also the groundwater data following <br /> redevelopment will be informative as well. <br /> I do not concur that groundwater samples are not necessary from the two remaining soil <br /> borings. Chevron needs to drill the borings and collect the soil and groundwater samples <br /> as approved in my 9 February 2010 letter. <br /> The report is now due 1 August 2010 and should summarize the results of the field work and <br /> the analytical data. Chevron may consider including an estimate of when Site groundwater <br /> data will reach WQOs so that I may again review the Site for closure. <br /> Let me know if you want to discuss. <br /> Kristi Shelton, P.E. <br /> Water Resources Control Engineer <br /> California Regional Water Quality Control Board - Central Valley <br /> Phone: 916-464-4819 <br /> Fax: (916) 464-4797 <br /> Email: kshelton@waterboards.ca.gov <br /> I <br /> To comply with the Governor's Executive Order calling for furloughs, the Central Valley <br /> Regional Water Quality Control Board Office and offices of the California Environmental <br /> Protection Agency are closed the first, second, and third Friday of each month. I <br /> apologize for any inconvenience this may cause. <br /> i <br /> >>> "Koschel, Dana" <Dana.Koschel@arcadis-us.com> 6/3/2010 5:09 PM >>> <br /> Kristi, <br /> I <br /> Per our voice message earlier today, ARCADIS would like to discuss the assessment <br /> activities proposed for the Corral Hollow and Grant Line Roads site located in Tracy, <br /> California. To date, ARCADIS has completed the following work: <br /> (1) Advanced soil borings HB-1 and HB-3 to a depth of 15 feet bgs. Soil samples were <br /> collected from each.boring at depths of 4 and 8 feet bgs. Depth to groundwater was <br /> approximately 9 feet bgs at these locations. Temporary monitoring points were installed <br /> in each boring. Advancement of soil borings HB-2 and HB-4 had to be postponed due to <br /> heavy rain and have yet to be completed. Analytical results for the soil samples did not <br /> indicate detectable concentrations of TPHd, TPHg, BTEX, or naphthalene (see attached <br /> table) . HB-1 and HB-3 were advanced immediately adjacent to the Delta Blood Bank property <br /> boundary. <br /> 1 <br /> I <br /> i <br /> I <br />