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MEETING MINUTES DISCO PROPERTY DATA REVIEW AND FUTURE ACTIVITIES SCOPING February 11,1998 San Joaquin County Environmental Health Division Attendees: Ron Rowe/SJCEHD,Margaret Lagorio/SJCEHD,Richard Fish/Del Monte, Steve Ronzone/Del Monte,Nancy Bice/Geomatrix,Liz Dodge/CH2MHILL Minutes Prepared by Liz Dodge Additions and Corrections to these minutes should be conveyed to Richard Fish/Del Monte or Liz Dodge/CH2M HILL.If no changes are proposed by March 11,1998,these minutes will be assumed to be complete and correct. Ron Rowe described his impressions of the data summary and visualization package and identified the following data gaps: • Of the 33 boreholes drilled at the Disco Property,20 did not have chemical constituents analyzed for in soil. Ron indicated that more chemical data on soils were needed. Specifically,he noted that the soil gas survey data on Table 2 indicates that soils in the upper to 13 feet in the dispenser area are relatively clean and analytical data on soils are available from 6 wells at depths of 5 to 85 feet. However, Ron indicated that more soil analytical data is needed in the zones from 13 to 55 feet and greater than 85 feet below grade. Liz Dodge indicated that additional vadose zone sampling did not seem .%-arranted in the dispenser area,since no indication of a release was found during Ko"'.piping removal. Ron said that sampling in the saturated zone should have been performed in this area. e0w, • The cross sections did not show deeper wells MW-7D or MW-8D. He also said wells 1\1W-8S and MW-8D should have been included in cross section 3. • Ron felt more borings may be warranted between MW-8 and MW-2,below 80 feet below grade, although access is limited by the presence of Myrtle Street. • Table 3 -Ron asked about the high TPH concentrations listed as 3 feet below grade at the north Tank. Liz indicated that the table should indicate that the sample depths are feet below the bottom of the tank excavation. Ron noted that historical analytical data indicate highest concentrations in soil were observed near the north tank at 65-75 foot below grade interval • Ron felt geologic cross sections were"oversimplified" may need more detail. He asked if CH2M HILL instructed EMCON on how to draw the cross sections; Liz Dodge replied that EMCON was provided the boring logs and asked to use their best judgement. Ron noted that in the late 70's groundwater levels were 100 to 110 feet below grade,based on flood district maps, and therefore petroleum constituents may be present at this depth or