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A S S O C I A T E S I N C LABORATORY ANALYSIS Groundwater samples from the monitoring wells were placed on ice and transported under chain- of-custody protocol to Sequoia Analytical laboratory Groundwater samples from wells MW1, MW4, MW6, and MW7 were analyzed for TPHg and TPHd by EPA method 8015 modified, and BTEX and methyl tertiary butyl ether (MTBE) by EPA method 8020 ANALYTICAL RESULTS The groundwater sample from well MW 1 contained benzene and ethyl benzene at concentrations of 400 ppb and 7 8 ppb respectively The laboratory reported the chromatogram patterns indicated both gas and diesel are present in well MW1 Also, MTBE per EPA method 8020 was reported at a concentration of 26 ppb, howcver_glLs report was not confirmed by EPA labontory mem 826.0 Previous groundwater samples were analyzed for fuel oxygenates utilizing PA method 8260 and none were detected indicating the recent detection of MTBE is a false positive most likely due to chromatogram interference The groundwater sample from MW4 contained benzene at a concentration of 1 0 ppb Also detected were TPHg (130 ppb) and TPHd (170 ppb) The sample from MW6 was likewise reported to contain TPHg (110 ppb) and TPHd (220 ppb) The sample collected from well MW7 contained only TPHd at a concentrations 51 ppb The chromatogram pattern for these samples did not match that of a fresh diesel pattern and was reported by the laboratory as an unidentified hydrocarbon Only the water sample collected from MW-1 contained concentrations of benzene in excess of the State of California Maximum Contaminant Level (MCL) of 10 ppb The reported concentration of benzene in MW 1 was 40Q 2pb, a decrease since the well was last sampled in June 1998 No other petroleum constituents were detected above MCLS Analytical results for groundwater are summarized in Table 2 Laboratory data sheets and chain of custody documentation are included as Attachment 2 FREE PRODUCT REMOVAL Free product has been monitored and removed from MW2 monthly since a passive skimmer was installed in this well on June 27, 1997 Dunn the third quarter 1998, a total of 0 4 liters of product were removed To date a total 15 91 titers f product have been removed from the skimmer placed in MW2 A summary of pro uct volume removed and previous product analytical data is presented in Table 3 . On August 14, 1998, during a scheduled visit to empty the skimmer reservoir, the double containment drum in which the removed free product was stored was missing ATC personnel searched the entire site along with the adjacent properties, however, no evidence of the drum or 625811QUARTLY\3QR-1998 DOC 3