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. the system recovered 2 66 gallons of gasoline from the vadose-zone during the three months To date, the AS/VE remediation system has recovered and iemediated 527 05 gallons of gasoline at the site A graph showing the influent aii concentration of TPH-G over time is presented in the Graphs section of this report 7.0 CONCLUSIONS lsoconcentration contour maps for TPH-G, benzene, and MTBE in the shallow water-bearing zone are presented as Figures 5 through 7, respectively The TPH-G and BTEX concentrations have increased in monitoring wells MW-5, MW-13, MW-14, and MW-16, and the TPH-G concentration has also risen in MW-19 The TPH-D concentrations have increased to all monitoring wells sampled with the exceptions of MW-3, MW-5, MW-6 a n d MW-7 although the laboratory noted that the hydrocarbons reported as TPH-D do not exhibit a typical diesel chomatographic pattern for MW-3, MW-4, MW-8, MW-9, MW-10, and MW-12 Hydrocarbon concentrations have continued to decrease in the groundwater sample collected from monitoring well MW-6 with TPH-D as the only parameter above the laboratory method reporting limit Benzene and MTBE concentrations in monitoring wells MW-13, MW- 14, MW-16, and MW-19 exceeded the California Department of Health Services (DHS) maximum contaminant level (MCL) for drinking water Additionally, the MTBE concentration in monitoring well MW-20 and the toluene, ethyl- benzene, and total xylenes concentrations in MW-14 also exceeded the DHS MCL for drinking water 8 . 0 RECOMMENDATIONS ASE recommends the following • continued groundwater monitoring of the site wells as prescribed in t h e RWQCB sampling frequency document • continued operation of AS/VE system through the next quarter • continued sampling, operation and maintenance of the domestic wells and treatment systems Frank's One Stop Quarterly Report — July 2003 Sampling -5-