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4 0 CONCLUSIONS AND RECOMMENDATIONS <br /> Based on the results of the completed scope of work, Ramage Environmental achieved the <br /> project objectives and concludes the following <br /> No sensitive receptors located within the site vicinity appear to be threatened by the gasoline <br /> hydrocarbons in soil and groundwater, originating from the former UST system at the site No <br /> active water supply wells or schools were found within 2,000-feet of the site The nearest active <br /> water supply well is located on the San .Joaquin County Fairgrounds and is approximately 2,100 <br /> feet southeast of the site The nearest surface water body is the ephemeral Mormon Slough, <br /> which may contribute to groundwater recharge to the site vicinity <br /> Analytical results from samples collected from the four new off-site monitoring wells indicate that <br /> the lateral extents of impacted soil and groundwater are defined Based on the cumulative soil <br />' sample analytical results, the lateral extent of impacted vadose zone soil appears to be limited to <br /> the footprint of the former UST excavation Based on the groundwater analytical and monitoring <br /> results, the plume of impacted groundwater probably extends from the vicinity of the former UST <br /> system to the southeast beneath the East Charter Way right-of-way (Figure 5) <br /> The expanded groundwater monitoring well network indicates that groundwater flow may be more <br /> toward the east-southeast Prior to the installation of the four new off-site wells, a slight <br /> groundwater depression observed at MW-2 may have indicated a more south-southeast <br /> groundwater flow direction <br /> Based on these conclusions, Ramage Environmental recommends the following <br /> 1 To further define the vertical extent of impacted groundwater, complete two additional CPT <br />' borings and collect additional discrete groundwater samples, as outlined in Ramage <br /> Environmental's Status Report and Work Plan Addendum dated March 27, 2001 These tasks <br /> were already approved by PHSIEHD on April 30, 2001 Based on the east-southeast <br />' groundwater flow direction, the off-site CPT boring should be located near MW-4, on the San <br /> Joaquin County Fairgrounds <br /> 1 2 To further delineate the nature and extent of metallic debris and/or buried drums within the <br /> former excavation, complete a geophysical survey of the former UST excavation area This <br /> task was also already approved by PHSIEHD on December 27, 1999 I <br /> 3 On a quarterly basis, continue to monitor and sample groundwater from the monitoring well <br /> network <br /> 14 <br /> x <br />