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Mr. Robert Trommer '' Page 3 of 7 <br /> ' Comments on.CUF Site Closure Recommendations for Various Sites March 3, 2010 { <br /> Claim No. 3484 - 2360 East Street, Tract/ <br /> This site is in,the closure process needing only monitoring well destruction. The EHD is awaiting <br /> the permit applications for the well destructions and anticipates site closure in one to three <br /> months. <br /> i <br /> Claim No. 679 - 5814 E. Charter Way, Stockton <br /> This site is in the closure process needing only monitoring well destruction. The EHD <br /> anticipates site closure in one to three months. <br /> Claim No. 7709 - 2969 Loomis Road, Stockton i <br /> As the EHD commented in May 2009 to the CUF five-year review closure recommendation, <br /> there are several. factors that lead the EHD to consider closure of this site to be premature at <br /> this time. Those factors are as follows: <br /> • All eight monitoring wells have groundwater above the wells screened intervals (as much <br /> as twenty feet in MW-1). There appears to be a correlation between depth-to-water and I <br /> concentrations detected in. groundwater from the monitoring wells - as depth-to- <br /> groundwater increase, diesel concentrations also increase. <br /> • The EHD is concerned about the sudden drop in diesel concentrations reported in <br /> groundwater collected from MW4, MW-S,, and MW-7 in April 2008. The significant <br /> decrease coincides with a change in laboratories. During the October 28, 2008, <br /> sampling event, groundwater samples collected from MW-5 and MW-7 were sent to two <br /> different laboratories, and the results from the two laboratories were significantly <br /> different. The verification,laboratory reported diesel at 2,210 micrograms per liter (ug/L) <br /> in MW-5 and 7,480 ug/L in MW-7, while the laboratory that had been detecting markedly <br /> lower concentrations reported diesel at 580 ug/L in MW-5 and 620 ug/L in MW-7. <br /> • Based on the soil contaminant mass for diesel estimated to be approximately 27,000 <br /> gallons (168,000 pounds) at the end of 2005, our department believes it prudent to try to <br /> remediate the diesel contamination prior to' closing this site, especially since.a light <br /> sheen continues to be reported in monitoring MW-4 and MW-5. <br /> Three dual-phase extraction wells with well screens that intersect the groundwater table were <br /> installed on the site in January. 2010, but have not been developed or sampled as of yet.. <br /> Considering that the characterization of shallow groundwater has not yet been completed and <br /> that an estimated 168,000 pounds of diesel is believed to be impacting soil and no remediation <br /> has yet been attempted, the EHD believes it would be beneficial to attempt some site <br /> remediation, reduce the contaminant mass and potential toxicity to microorganisms, and <br /> accelerate the return to background conditions. <br /> •E <br /> Claim No. 8509 - 1207 S. Aurora Street, Stockton <br /> This site is in the closure process needing only monitoring well destruction. The EHD anticipates <br /> site closure in one to three months. <br /> Comments on CUF Site Closure Recommendations 0310.doc <br />