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1 <br /> ' ARCADIS 2009/2010 Annual <br /> Monitoring Report <br /> Union Pacific Railroad <br /> Company <br /> ' Former Maintenance Facility <br /> The dual-phase extraction (DPE) system, consisting of eight dual-phase extraction Tracy,California <br /> wells and three soil vapor extraction (SVE)wells, was installed for source area <br /> ' treatment. The margin extraction system was installed to control potential off-site <br /> migration through the use of a pump-and-treat system,with extraction along the <br /> property boundary and re-injection upgradient of impacted groundwater. <br /> The DPE system was shutdown in July 2002 to perform a rebound evaluation and the <br /> margin extraction system was shutdown in May 2004 due to maintenance issues. In <br /> their October 6, 2005 letter, the RWQCB approved the continued shutdown of the <br /> margin extraction system and requested further evaluation of the source area. UPRR <br /> submitted a work plan entitled Rebound and Remediation Effectiveness Evaluation <br /> ' Addendum Work Plan to the RWQCB on January 3, 2006 for this additional evaluation. <br /> In addition, UPRR submitted a report entitled Additional Product Removal Proposal on <br /> August 28, 2006.The RWQCB provided comments on these two work plans in their <br /> letter dated November 20, 2006. <br /> As described in ARCADIS' November 26, 2009 letter to the RWQCB, UPRR changed <br /> environmental consultants in late 2006 and ARCADIS took over the Former Tracy <br /> Maintenance Facility project.ARCADIS has completed Phase I of the Liquid Petroleum <br /> Hydrocarbon Investigation and has partially delineated the distribution of free-phase <br /> petroleum in the source area.ARCADIS submitted the Phase II Liquid Hydrocarbon <br /> Work Plan in early 2009 and completed the additional source area investigation during <br /> ' the Winter of 2009. Results of the Phase II Liquid Hydrocarbon Investigation will be <br /> provided under separate cover. <br /> ' Both systems remained shut-down during the 2009/2010 monitoring period.The <br /> associated WDR No. 98-213 was rescinded in a letter submitted to UPRR by the <br /> RWQCB and dated May 22, 2009. <br /> 7.2 Mass Removal <br /> ' Free-product removal activities were not scheduled to be conducted during the <br /> 2009/2010 monitoring event. Past attempts at free-product have not been effective; <br /> therefore, ARCADIS is evaluating more efficient free-product remedial alternatives. <br /> ' 8.0 Conclusions and Recommendations <br /> ' Based on evaluation of the groundwater sampling data,ARCADIS concludes the <br /> following: <br />' P:NRVDIS Dem\P,q'ecbPc(rve\Union Peds Rtil,md,RCJO]-Trery YeMDtlNerad�GW Monpa��p16UC T,rcy VvtlPmxlGW p092t1P,FINgL�2S10 r1nnel <br /> Pio °o Page:6/7 <br />