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r <br /> . A S S O C I A T E S I N C <br /> ANALYTICAL RESULTS <br /> TPI-Ig was detected in the groundwater samples collected from MW1, MW2, and MW3 at <br /> concentrations of 190 micrograms per liter (µg/L), 470 µg/L, and 2,500 µg/L, respectively Benzene <br /> was detected in the groundwater sample collected from MW3 at a concentration of 14 µg/L Toluene <br /> was detected in the groundwater samples collected from MW2 and MW3 at concentrations of 2 1 <br /> µg/L and 3 5 µg/L, respectively Ethyl benzene was detected in the groundwater samples collected <br /> from MWl and MW3 at concentrations of 4 6 µg/L and 17 pg/L, respectively Xylenes were detected <br /> in the groundwater samples collected from MW2 and MW3 at concentrations of 1 0 pg/L and 86 <br /> pg/L, respectively MTBE was not detected in any of the groundwater samples Analytical results of <br /> groundwater samples are summarized in Table 2 Laboratory data sheets and chain-of-custody <br /> documentation are contained in Attachment 2 <br /> CONCLUSIONS <br /> The groundwater flow direction calculated for March 2, 2005, Is not consistent with previous <br /> sampling events, as the predominant historical direction of groundwater flow is to the northwest <br /> Water table elevations have increased beneath the site since December 2004 Benzene has not been <br /> detected in samples collected from MWI and MW2 for the last two consecutive sampling events The <br /> concentration of benzene detected in the groundwater sample collected from MW3 decreased with <br /> respect to the previous sampling event TPHg concentrations in the groundwater samples collected <br /> from MWl and MW2 decreased with respect to the previous sampling event, and Increased in the <br /> sample collected from MW3 MTBE has never been detected in groundwater samples collected from <br /> MW 1, MW2, and MW3 <br /> RECOMMENDATIONS <br /> Based on recent lack of benzene concentrations at or above the laboratory reported detection limits in <br /> groundwater samples collected from MW1 and MW2, and low benzene concentrations in <br /> groundwater samples collected from MW3, we recommend the site be considered for closure <br /> Please contact our office at(209) 579-2221 if you have any questions or comments <br /> Respectfully submitted, <br /> ATC Associates Inc <br /> Todd Hafner <br /> Project Geologist <br /> Y11PO <br /> J nne Homsey, P E <br /> CA Registered Civil Engineer No 47410xL'�` 7{ <br /> cc Mr Paul Van Dyken, Sr , N & S Irrigation <br /> Jim Barton, RWQCB <br /> Attachments <br /> s lenvironmentaiu498IIReports\1QR-05 doc 3 <br />