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' First Quarter 1999 Monitoring and Sampling Report 2 The Southland Corporation,Store#19976,1399 North Main Street Manteca CA March 19, 1999 MONITORING WELL SAMPLING AND ANALYTICAL RESULTS ' On February 18, 1999,groundwater samples were collected from four wells Before sampling, at least four well-casing volumes of groundwater were removed from each monitonng well unless the well was purged dry The groundwater samples were collected using disposable bailers Groundwater samples were placed in analysis-specific containers with analysis-specific preservative The samples were then sealed using Teflon septum caps, labeled with the fob identification number,the sample number, date,time, and type of laboratory analysis required The samples were stored on Ice and transported with a chain-of- custody record to Acculabs, Inc , in Davis, California Groundwater samples were analyzed for BTEX and TPH-G using Environmental Protection Agency(EPA) method 8020/modified 8015 and for the oxygenates TBA, MTBE, DIPS, ETBE and TAME using EPA method 8260 ' Laboratory analytical results for groundwater samples collected on February 18, 1999 and historical reports are summarized in Table 1 The highest concentrations of benzene,TPH-G and MTBE were reported in groundwater sampled from MW-2 at 5,700 micrograms per liter(pg/L), 57,000 pg/L and 630 pg/L, ' respectively Benzene, TPH-G and MTBE concentrations increased in well MW-2 (downgradient) Hydrocarbon and oxygenate concentrations remain non-detectable or very low in wells MWAA(the deep monitoring well) and MW-3 (upgradient) and have remained relatively stable in well MWA The laboratory analytical reports for the groundwater samples are included in Attachment 4 ' Dissolved oxygen data taken from the four monitoring wells on February 18, 1999, indicate depletion of dissolved oxygen through ongoing Intrinsic biodegradation Dissolved oxygen levels continued to decrease in all wells Dissolved oxygen levels ranged from 0 25 milligrams per liter(mg1L) to 0 47 mg/L (Table 1) PURGE WATER TRANSPORTATION AND DISPOSAL All purge water generated during this quarterly monitoring and sampling event was stored in 55-gallon Department of Transportation (DOT)-approved drums pending characterization and proper disposal ' Approximately 51 gallons of purged water generated during this sampling event will be removed from the site during the next quarter by Belshire Environmental Services, Inc and transported to a licensed treatment and disposal facility i 1 ' IT CORPORATION