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`1 Mr.Nuel Henderson Page 3 of 4 Laboratory analysis consisted of gasoline oxygenates [tert-butyl alcohol (TBA), methyl tert-butyl ether (MTBE), di-isopropyl ether (DIPE), ethyl tert-butyl ether (ETBE) and tert-amyl methyl ether (TAME)], ethylene dibromide (EDB) and 1,2-dichloroethane (1,2-DCA) by EPA Method 826013; total petroleum hydrocarbons as gasoline (TPHg) by EPA Method 8015M; benzene, toluene, ethylbenzene and xylenes (BTEX) by EPA Method 8021 B; general minerals by various EPA Methods; California Analytical Method (CAM) 17 dissolved metals by EPA Method 200.8; hexavalent chromium (Cr+6) by EPA Method 218.6,bromide (Br)by EPA method 300.0; bromate (Br03)by EPA Method 300.1; and ORP by the Langelier Method. Purge water was transferred into labeled 55-gallon drums approved by the Department of Transportation (DOT). The waste is stored onsite within a secured area. Purge logs are included in Attachment A. ` GROUNDWATER ANALYTICAL RESULTS Remedial Injection Performance Monitoring Groundwater samples were collected from wells V W I and VW2 on March 28, 2011 and from wells MW2, MW5, MW1313, VWl and VW2 on May 17, 2011. The samples were analyzed for ►. pH, temperature, EC, DO, ORP, TPHg, BTEX compounds, gasoline oxygenates, general minerals, CAM-17 Metals, Cr+6, Br and Br03 to monitor groundwater conditions during the H2O2 injection pilot testing. A summary of the hydrocarbon and oxygenate results are provided as Table 3, a summary of the groundwater chemistry results are provided as Table 4, and a summary of the dissolved metals results are provided as Table 5. Attachment B contains laboratory reports and chain of custody documentation.Notable results are summarized as follows: • In general, the shallow groundwater quality shows signs of improvement with declining conductivity and total dissolved solids. However, several metals and compounds continue to exceed drinking water MCLS. TPHg and benzene were detected in all sampled wells during the March 28, 2011 and May 17, 2011 sampling events. Since the initiation of remedial H2O2 injections concentrations of ` TPHg and benzene have declined significantly in wells MW5, MW1313, VW1 and VW2; However, TPHg and benzene concentrations in MW2 have increased slightly since H2O2 injections began. Graphs showing concentrations of TPHg and benzene over the last four years in the performance monitoring wells have been included in Attachment C. • Cr and Cr+6 were not detected above laboratory detection limits in any of the sampled wells during the baseline groundwater sampling event in August 2010. Cr+6 was subsequently detected in wells VWl and VW2 during both the December 23, 2010 and February 2, 2011 sampling events. Cr+6 was detected in injection well VW2 in March and May 2011. Additionally, Cr+6 was detected in transition well MW13B on May 17, 2011 which is supporting evidence that the effect of peroxide injection is being manifested downgradient of the injection points. • Br03 was not detected in any sampled well on March 28, 2011; however Br03 was ` detected during the May 17, 2011 sampling event in wells VWl, VW2 and MW13B at concentrations of 0.53 parts per million (ppm), 0.35 ppm and 0.46 ppm, respectively. The L GAGROUNDZEIROEKIREPORTST=xide Pilot Tesfacportsl2QTR20l l Remedial Prowess Report.doc