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(k.j, the soil bulk density(Pb) and soil porosity(0). PCE and TCE typically can move 1.5 to 3 <br /> times slower than groundwater depending on these parameters (Geomatrix, 2003). <br /> The available monitoring wells and HydroPunch data suggest that VOCs in groundwater have <br /> migrated downward into deeper intervals possibly under the influence of pumping from City <br /> wells CW#2, CW#4, and CW#24 in the LNC vicinity(Figure 5). The rate of pumping from <br /> these wells in response to the groundwater contamination has likely altered the migration <br /> pathway for VOCs in groundwater. Potentially, there is less downward and lateral migration <br /> because City wells CW#2 and CW#4 are no longer active. However, the fact that CW#24 is still <br /> active and is the closest to the LNC facility may continue to provide a downward migration <br /> potential of VOCs. <br /> 5.4 Identified Data Gaps <br /> Data gaps have been identified at the LNC site as follow: <br /> • Unknown concentration and distribution of VOCs within vadose zone below 25 feet bgs <br /> (below the "A" Clay); <br /> • Unknown concentration and distribution of VOCs within first water bearing zone at about 50 <br /> feet bgs immediately below the identified past VOC probable release areas. <br /> • Identification of the soil remediation technology that will be most efficient and cost effective <br /> to remediate onsite VOC impacted soil. <br /> M ain\D:AEnvironmenta1\LN CV\10152007.wpd 32 <br />