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r The most evident pattern of conductivity at the site is lower conductivity between about 43 and 59 feet bgs (see graph on bottom of page 31 of Vironex report (Appendix C) This corresponds to the zones of maximum PID and FID MIP response (see graphs on page 30 and 31 of Vironex report) as well as zones of sand identified in the borings discussed above (Section 3 1 1, Appendix E) 3.1.3 Groundwater Occurrence and Flow ' The depth to water has varied between 19 and 27 feet bgs in site wells in the last several years Groundwater was measured at depths of 12 73 to 2167 feet below tops-of-casing on February 6, 2006 The February 6 depths were about 10 to 12 feet below mean sea level 1 The Port of Stockton is located to the north and west of the site and local groundwater is inferred to flow eastward from the port The operation of the port and pumping of groundwater farm supply wells in the Stockton vicinity are believed to control the depth and the groundwater gradient in the areaOr Most of the 2e century Both rainfall pattern and patterns of ' groundwater extraction have resulted in fluctuating water table depths and some variability in direction of groundwater flow r3.2 Laboratory Analysis for Contaminants 32.1 Sol! Soil samples retrieved from borings DP-4, DP-6, DP-8 and DP-9 were chilled in a cooler and transported via United Parcel Service (UPS) to the Applied Physics and Chemistry Laboratory (APCL) in Chino, California, using standard chain-of-custody procedures The samples were analyzed for compounds listed in Section 2 3 Soil analytical data are summarized in Table 1 The certified analytical reports and chain-of-custody documentation for soil samples collected for this investigation are included in ' Appendix D Twenty-five soil samples were collected at various depths in each boring location The shallowest sample collected was 25-26 feet bgs in boring DP-8 The deepest of samples came from DP-9 at 69-70 feet bgs The greatest number of samples were retrieved from depths between 37 and 55 feet bgs, which corresponded to the depths of greatest of contamination indicated by the MIP 3.2.2 Groundwater by Direct-Push Groundwater was extracted from boring MIP-1 at a screened depth of 24-27 feet bgs The sample bottles were filled, labeled and double bagged in bubble wrap then immediately placed on ice The cooler later transported via UPS to Applied Physics and Chemistry Laboratory (APCL) in Chino, California, using standard chain-of-custody procedures SacDP-N ITecRPub4120221 Don Rodgem0pW SIRlSpnng2006 SIR(August)doc r3_2 I� 62308 t