ARCHIVED REPORTS XR0000815 - Laserfiche WebLink

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Date- July 22,2005 Quarter. 2°d Quarter,2005 ANALYTICAL DATA REVIEW: Based on the review of the analytical and hardcopy data (chain-of-custody records,blanks, dilutions, holding times, LCS/LCSD results, MS/MSD results,and surrogate recoveries),the data are acceptable as reported by the laboratory with the following]imitation • The elevated reporting limits were the result of dilutions performed by the laboratory in order to quantitate a target analyte DISCUSSION: Gasoline range organics (GRO), benzene, toluene, ethylbenzene, total xylenes (BTEX), methyl tert-butyl ether (MtBE), Cert-amyl methyl ether (TAME), 1,2-dichloroethane (1,2-DCA), and 1,2-dibrobmoethane (EDB) were detected above laboratory reporting limits in groundwater samples collected from site wells this quarter MtBE concentrations in MW-1 increased but remained consistent with second quarter 2004 In MW-3, total xylenes were detected at the laboratory reporting limit, the first detection since December 2003 In MW-4, MtBE concentrations increased A low-level concentration of MtBE was detected in MW-8 this quarter Other analyte concentrations were generally consistent with historic data There was sufficient groundwater in site well VW-4 to be sampled for the first time since installation during second quarter 2004 GRO, toluene, ethylbenzene, total xylenes, MtBE, TAME, and EDB were detected above laboratory reporting limits in the groundwater sample collected from VW-4 this quarter Groundwater elevations in wells across the site increased relative to the previous quarter The inferred groundwater flow direction across the site was toward the southeast at an average hydraulic gradient of 0 02 ft/ft The SVE system began operations on August 30, 2004 Approximately 439 0 lbs of GRO, 0 00 lbs of benzene and 0 84 lbs of MtBE were removed during the second quarter 2005 The SVE system operated in compliance with the San Joaquin Valley Air Pollution Control District (SJVAPCD) Initial sampling and flow data was submitted to SJVAPCD on September 28, 2004 A performance evaluation of the remedial systems between April 1, 2005, and June 30,2005,are presented as Appendix A K 1Wpoo.es\J5 Bp ARCo\021861Qumiu 1yU00512 QTR 05\2186 GWMR 2Q05 do Page 2