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r• n Mr Harlin Knoll July 31, 2000 r Page 2 of 2 P 2 Groundwater samples were submitted to Argon Laboratories (ELAP #2359) for analysis of TPHg and BTEX utilizing EPA methods 8015 modified and 8020, respectively Dissolved gasoline constituents were detected in wells MW1, MW4, and MW5 No dissolved contaminants were detected in wells MW8 ANALYTICAL RESULTS Elevated levels of dissolved gasoline constituents were detected in groundwater samples collected from well MWS, and very low levels were detected in wells MW 1 and MW4 No gasoline constituents were detected in well MW8 Well MW5 contained TPHg at 55,000 parts per billion (ppb) and benzene at 6,500 ppb, reductions of approximately 13% and 31%, respectively, since May 1999 MW 1 contained TPHg at 160 ppb, and benzene at 2 4 ppb, an increase from the non-detect results in May 1999 However, the current levels of TPHg and benzene in well MW 1 represent reductions of approximately 58% and 76%, respectively, from November 1999 levels Well MW4 contained toluene and xylenes at less than 1 0 ppb Figure 3 presents a benzene isoconcentration map from the May 2, 2000 groundwater sampling event Analytical results are summarized in Table 2 Laboratory data sheets and chain of custody documentation are included in Attachment B Attachment C contains graphical representations of TPHg and benzene concentrations over time in each site well The next anticipated monitoring and sampling event is scheduled for August 2000 Please contact John Lane at (209) 838-9888 if you have any questions or comments regarding this submittal Sincerely, Ground Zero Analysis, Inc �0 cr JOHN P Ni J_t_Lp LANCE No 6795 John P Lane CA Registered Geologist 6795 �p OF C AV'V' JPL Attachments cc Mr Carl Knowles Mr Patrick D Riddle, Esq CRWQCB Sacramento knowles ham/reports/2gm2000 Aoc