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Meeting Minutes 3130100 <br /> Page 5 of 7 <br /> • 5. Future Nestle Remedial Actions <br /> Future remedial actions were briefly discussed during presentation of agenda items 3 and <br /> 4 Although the details of the remedial actions have not been worked out yet, the cleanup <br /> approach currently being considered would include the following <br /> o Potassium permanganate would be used to reduce TCE mass at the site and <br /> other hot spots <br /> © Based on the modeling results, a cleanup strategy will be developed which may <br /> include groundwater extraction well(s) This remedy would be used to cleanup <br /> most of the plume and protect the impacted and/or threatened municipal supply <br /> wells <br /> • Alternative pumping scenarios for the municipal water well system will be <br /> explored using the groundwater flow model, with the objective of minimizing <br /> further spreading of the plume <br /> A more detailed discussion of the Nestle's remedial actions is proposed for the next <br /> technical meeting <br /> 6 Shell Investigation and Cleanup Actions <br /> Owen Ratchye (Cambria Environmental) presented a summary of Shell's investigation <br /> activities and discussed cleanup actions proposed for Year 2000 The attached <br /> information package was distributed at the inecting The following summary information <br /> was either presented by Owen or was interpreted from the attached information package <br /> • Gasoline leakage was discovered in 1996 when the former USTs were removed <br /> MTBE is the principal contaminant in the groundwater and has been detected at <br /> concentrations exceeding 100,000 gg/l near the former USTs Methanol and <br /> BTEX have also been detected in the groundwater <br /> • Although the lateral extent of the groundwater plume has not been completely <br /> delineated, the available data suggest that concentrations exceeding the <br /> Secondary MCL of 5 µ.g11 may be limited to a 200 to 250-foot distance down <br /> gradient from the former USTs MTBE was not detected in well cluster MW- <br /> 6A, which is the only off-site monitoring well east (down gradient) from Shell <br /> Shell has also sampled the Caltrans well located approximately 200 feet <br /> southeast of the station and MTBE was not detected <br /> 1'71/fTD� aatpd h,it annPare to extend to a <br /> • Tue C. <br /> vellil+al AKd1L o " L,.. 1"::/� ..•++) +-��---^'__, __ _1 1 <br /> minimum depth of 65 feet bgs MTBE has migrated to the base of the B-aquifer <br /> . zone and possibly into the underlying A-aquifer zone <br />