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PAR-Eckert Cold Storage, Manteca,CA November 25, 2002 Page 4 . groundwater. The two CPT boring pairs were advanced in two locations to a depth sufficient to adequately evaluate the vertical extent of groundwater contamination in the vicinity of the former USTs and at the anticipated leading down-gradient edge of the plume. At each deep boring pair location, the first boring was advanced to provide a near-continuous log of the subsurface soil profile. The second boring at each pair location was advanced proximal to the first boring to collect a discrete groundwater sample from saturated horizons identified in geologic logs from the first borings. The boreholes were drilled by Gregg In Situ, Inc. of Martinez, California. A detailed presentation of the cone penetration test data and field equipment and procedures is provided in Appendix C. 4.2.1 Shallow direct push(hydropunch) boring procedures Ten shallow direct push borings (hydropunch) were advanced to a depth sufficient to collect a ' groundwater grab sample to provide data on the lateral extent of contamination in shallow groundwater. The first borehole (HP-1) was advanced to a depth of approximately 27 feet bgs, eight of the ten borings (HP-2 through HP-9) were advanced to a depth of approximately 25 feet bgs, and final borehole (HP-10) was advanced to a depth of approximately 30 feet bgs. One groundwater sample was collected from each direct push boring for a total of ten groundwater samples collected during the shallow groundwater investigation. The direct push borings were hydraulically advanced using a 2-inch diameter conical bit. The bit and associated push rods, the groundwater sampler, and the stainless steel bailer were steam-cleaned before each use. Each boring was grouted to the surface with neat cement upon completion of the boring and sampling. The cement was tremied into each borehole to avoid bridging. Groundwater samples were collected from the bottom of borings HP-1 through HP-10 using a Hydropunch® type groundwater sampling system. Groundwater samples were collected from depths �11 ranging from 21 to 30 feet bgs, depending on the depth that each boring was terminated. The groundwater sampler operates by pushing 1.75-inch diameter hollow rods with a retrievable tip. A stainless steel filter screen is attached to the tip. At the desired sampling depth, the rods are retracted exposing the filter screen and allowing for groundwater infiltration. A small diameter bailer is then used to collect groundwater samples through the hollow rod. Each groundwater sample was gently poured from the bailer into six 40-m1 glass, volatile organic analysis (VOA) vials. The sample containers were sealed, labeled,placed in a cooler chilled with ice, and 1 delivered under chain-of-custody procedures to a California certified laboratory for analyses. The groundwater samples were analyzed using U.S. EPA Methods and California-approved methods following quality assurance measures. The laboratory analytical methods are described in Section 6.0. 4.2.2 CPT boring procedures Cone-penetrometer (CPT) borings were advanced at two locations; CPT-1 was advanced to a depth of approximately 104 feet bgs, CPT-2 was advanced to a depth of approximately 100 feet bgs. CPT-I was advanced to evaluate the vertical extent of groundwater contamination in the vicinity of the former USTs. CPT-2 was advanced to evaluate the vertical extent of groundwater contamination at the anticipated leading down-gradient edge of the plume. At each deep boring pair location, the first boring of each group was used to investigate the lithology of the site at that location. An electric piezocone was pushed downward into the subsurface by the CPT rig. • Measurements of the cone bearing pressure, sleeve friction, and dynamic pore water pressure were recorded at approximately two-inch intervals to provide a nearly continuous geologic log. The two geologic logs were compared and correlated to identify potential horizons that are laterally extensive and is CONDOR