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' stantec <br /> ' L & M OPERABLE UNIT-THIRD QUARTER 2010 SITE STATUS, REMEDIAL SUMMARY, <br /> AND GROUNDWATER MONITORING REPORT <br /> Soil Vapor Sampling <br /> ' October 27, 2010 <br /> 4.2.4 Quality Assurance/Quality Control-Samples and General Laboratory Notes <br /> Duplicate samples APSV-10-D and UPSV-3D were collected from two soil vapor points <br /> (APSV-10 and UPSV-3, respectively) during the third quarter 2010 sampling event. All analytes <br /> in APSV-10 and APSV-10D were below laboratory reporting limits. The trip blanks did not <br /> contain analytes at or above laboratory reporting limits. A comparison of UPSV-3 and UPSV-3D <br /> is shown below. <br /> TPHg [ppmV) 7.3 6.6 +/- 10.1% <br /> Benzene mV <0.03 <0.03 0% , <br /> MtBE (ppmV) <0.03 <0.03 0% <br /> TBA(ppmV) <0.33 <0.33 0% <br /> ' 4.2.5 Conclusions and Recommendations <br /> ' TPHg was detected in five soil vapor samples at concentrations of 2.4 ppmV (APSV-1), <br /> 2.7 ppmV (APSV-9), 7.3 ppmV (UPSV-3), 6.6 ppmV (UPSV-3D), and 416 ppmV (UPSV-5). All <br /> ' other reported TPHg concentrations were non-detect (less than 2.4 ppmV) in the APSV and <br /> UPSV wells during the reporting quarter. BTEX, Naphthalene anfJ the five fuel oxygenates <br /> (MtBE, DIPE, EtBE, TBA, and TAME)were not detected at or above laboratory MRLs during the <br /> third quarter 2010. <br /> Based on data presented in this report, Stantec recommends continuing with the soil vapor <br /> ' monitoring schedule as presented in the Work Plan titled Revised Work Plan for Soil Vapor <br /> Assessment and Response to RWQCB Letter Dated May 3, 2005 and prepared by SECOR. <br /> Results of future sampling will be provided in Stantec's corresponding quarterly Site monitoring <br /> ' and sampling reports. <br /> ,t <br /> ' 1ATdemteATW SbcWn(Perc MA 415)\Reports\QMRt20100Q10\3Q10QSSRQRSRQMR Sto bn `e <br /> _RNALdw •3 <br />