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kTI KLEINFELDER I 6 CONCLUSIONS AND RECOMMENDATIONS i r On August 29, 30 and 31, 2005, 13 monitoring wells were and piezometers purged and sampled. Water samples obtained from each location were submitted for chemical analysis. Based on the data obtained during our assessment, the following conclusions and recommendations have been formulated: 1. Groundwater gradient at the site was estimated to be towards the east/southeast and relatively flat at 0.0004 ft./ft. 2. Eight well samples (MW-DIS-9, MW-DIS-11s, MW-DIS-11d, MW-DIS-12, and MW-DIS-13, MW-DIS-14s, MW-DIS-14d and MW-DIS-15) did not contain TPH-g, BTEX, TBA, and EDB above the laboratory reporting limits. Concentrations of 1,2- DCA were detected in MW-DIS-11 s, MW-DIS-12, MW-DIS-14s, and MW-DIS-15. The 1,2-DCA concentration in MW-DIS-11 s remained similar to the last quarter results with a slight decrease to 7 ug/I from the previous quarterly results (8 ug/1). The concentrations of 1,2 DCA detected in MW-DIS-12, MW-DIS-14s, and MW- DIS-15 show an increase versus previous results. The additional oxygenates MTBE, DIPE, ETBE, and TAME were non-detectable at or above the laboratory reporting limits in MW-DIS-15. MW-DIS-9 is located east of the former UST area and remediation facility and was sampled due to the past groundwater gradient direction change towards the east. The sample collected from MW-DIS-9 showed non- detectable concentrations. of TPH-g, benzene, toluene, ethyl-benzene, xylene, TBA, 1,2-DCA, and EDB. 3. Kleinfelder conducted a water well survey within a 2,000-foot radius of the site to ascertain whether any new wells have been installed and are pumping. DWR Well Drillers Logs were reviewed and showed no new water wells or multiple pumping wells within the 2,000-foot radius of the site. The seasonal fluctuations of groundwater elevations may be linked to naturally occurring rainfall/recharge, and/or groundwater extraction practices near the site. In areas of such flat gradients, slight changes in groundwater elevations can affect the groundwater flow directions. The groundwater elevations at the sight typically range between much less than a foot. 4. Kleinfelder recommends that monitoring of the site should be continued in accordance with the "Groundwater Monitoring Frequency Decision Tree" at this time. 5. A copy of this report should be submitted by Del Monte, Inc. to the San Joaquin County Environmental Health Department and the Central Valley Office of the State of California Regional Water Quality Control Board for their review and consideration. This report is subject to the limitations in Chapter 7 of this report. 12280.M0N/ST05R1424/CD:Iv Page 12 of 14 ©2005, Kleinfelder, Inc. November 15, 2005