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1 <br /> ' ARCADIS 2009/2010 Annual <br /> Monitoring Report <br /> ' Union Pacific Railroad <br /> Company <br /> Former Maintenance Facility <br /> concentrations in the A-Zone were generally similar to detections during previous <br /> Tracy,California <br /> monitoring events. Nine of the 19 A-zone wells sampled during the March 2010 event <br /> t contained TEPH-d detected at concentrations above the 100 µg/L CAO cleanup level <br /> (Table 4). TEPH-d SG was not detected in the 19 A-zone wells sampled (Table 4). <br /> ' 6.3.2 B-Zone <br /> TEPH-d and TEPH-d SG were not detected in the nine B-zone wells sampled during <br /> ' the March 2010 sampling event. <br /> 6.3.3 C-Zone <br /> ' TEPH-d and TEPH-d SG were not detected in the two C-zone wells sampled during <br /> tthe March 2010 sampling event. <br /> 6.4 Volatile Organic Compounds Analytical Results <br /> ' VOC analytical results for groundwater samples collected since February 2000 are <br /> summarized in Table 5.VOCs were not detected in the five wells sampled during <br /> ' November 2009. VOCs were detected in one of the 19 A-zone wells (MW-27A) and in <br /> one of the nine B-zone wells (MW-166) sampled during March 2010 at concentrations <br /> below their respective CAO cleanup levels.VOCs were not detected in the two C-zone <br /> ' wells sampled in March 2010. <br /> 6.5 Concentration Trends <br /> ' Figure 9 shows the extent of the TEPH-d in the A-Zone during the past five years. As <br /> shown on these figures, the TEPH and halogenated VOCs have stabilized within the <br /> ' boundaries of the site and concentrations have declined or remained stable in wells <br /> along the perimeter of the plume. <br /> 7.0 Remedial Activities Summary <br /> 7.1 Remediation System Operation and Maintenance <br /> ' There are two remediation systems present at the Tracy Maintenance Facility:the <br /> source area treatment and margin extraction systems. Neither of these systems is <br /> currently operating as approved by the RWQCB. <br /> Pwacnois o�worew-xw�w:, rx�r r�,oamacros-nxy v„anawareaencw row,ro„q�iooa rre,.vre,aa..,�rnN�oazoiasnuix�xioa,u� <br /> ' Aim Page: 5/7 <br />