ARCHIVED REPORTS_QUARTERLY GROUNDWATER MONITORING REPORT 1ST QUARTER-JANUARY 2010

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3.0 SUMMARY AND CONCLUSIONS ' Groundwater monitoring was first performed at the Site in 1999. A summary of current Site ' conditions is presented below: • During the quarterly groundwater-monitoring event, wells MW-1, MW-lA, MW-2A, ' MW-3A, MW-4A, MW-7S, MW-7D, VE-1, CT-MW-8-87, CT-MW-9-120, TX-MW-8-50, TX-MW-14-49, and TX-MW-21-80 were gauged and sampled. LPH was not detected in any of the wells. • Groundwater elevations ranged from -9.67 feet MSL in MW-3A to -9.85 feet MSL in MW-2A for the "A" zone wells. The direction of groundwater flow in the "A" permeable zone (as determined by wells MW-lA through MW-4A) was to the south with a hydraulic gradient of approximately 0.001 foot-per-foot. • Currently, it appears that the groundwater flow for the on-site Texaco wells is to the east at a variable gradient of approximately 0.004 foot-per-foot according to the fourth quarterly report (most current report available) for the Texaco site. Survey data for the Colombo/Toscana and Texaco wells do not correlate. ' • TPH-g was detected in groundwater samples from eight on-site wells. Some or all of the BTEX compounds were detected in samples collected from six wells. The ' concentrations of benzene in samples from MW-1, MW-7S, MW-7D, and VE-1 exceeded the California MCL. The concentration of toluene, etbylbenzene, and xylenes in the sample from VE-1 exceeded the MCLs. • MTBE was detected in samples from seven wells. The concentrations of MTBE in the samples from MW-1, MW-7S, VE-1, and CT-MW-8-87 exceeded the California ' MCL. TBA was detected in samples from six wells. DIPE was detected in two wells. ETBE was not detected in any of the Colombo/Toscana wells. TAME was not detected in any of the samples. • 1,2-DCA was detected in one well. The concentration of 1,2-DCA in the sample from MW-7D exceeded the MCL. 1,2-DBA was not detected in any of the samples collected during this quarterly event. • For the on-site Texaco well TX-MW-8-50, the results were all non-detect. The results for TX-MW-14-49 reported concentrations of MTBE, ETBE, TBA, and 1,2-DCA. ' The results for TX-MW-21-80 reported concentrations of TPH-g, BTEX, and TBA. A source of petroleum hydrocarbon impact beneath the Site is the two former 4,000-gallon ' gasoline USTs. A secondary source of impact to groundwater is the residual petroleum hydrocarbons in the soil beneath the former USTs. Analytical data from the Site and neighboring LUFT investigations indicate that petroleum hydrocarbon-impacted groundwater beneath the sites is commingled into one large plume. ' Quarterly Groundwater Monitoring Report First Quarter—January 2010 Prepared For:Sara Lee Bakery Group,Inc. Prepared By:PSC Industrial Outsourcing,LP Sam Lee—Lincoln Street\2010_01_Ql-QMR(Lincoln).doc May 10,2010 10