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• nase II Environmental Site Assessment <br />Heritage Square <br />Page 4 <br />diameter cutting shoe. The hand auger borings were manually advanced using a 3 -inch diameter bucket. <br />The cutting shoe, hand auger bucket, and associated push rods were thoroughly cleaned before each use <br />with laboratory -grade, non -phosphate detergent and de -ionized water and double -rinsed with de -ionized <br />water. Upon completion of the drilling and sampling, the direct pushboreholes were backfilled with grout <br />and the hand auger boreholes were backfilled with clean aggregate base and capped with concrete. <br />4.3.1 Soil Sampling <br />Soil samples were collected from each Geoprobe° boring from approximately two feet below the bottom <br />of the respective nearby UST and at five-foot intervals thereafter to a depth of 10 feet below the deepest <br />evidence of hydrocarbon contamination or 30 feet bgs, whichever was greater. A minimum of two soil <br />samples from each boring were retained for laboratory analyses. Borings B-1, B-2, and B-4 were <br />advanced to approximate depths of 20 feet bgs, and borings B-6 through B-8 were advanced to <br />approximate depths of 16 feet bgs. As field observations indicated that contamination was present in <br />boring B-3 east of TKI, samples were collected at less than five-foot intervals through the impacted zone, <br />a total of seven samples from the boring were retained for analyses, and the boring was advanced to a <br />depth of 36 feet bgs. Obvious indicators of contamination were present near TK2 in boring H -j as well, <br />and a total of three samples from this boring were retained for analyses and the boring was advanced to a <br />depth of 40 feet bgs. Ground ter samples were also collected from each of these impacted borings. <br />Sample depths for borings B-1 through B-8 are indicated on the geologic logs in Appendix B.Borings C- <br />1 through C-4 were advanced to approximately two feet beneath the underground piping. Soil samples <br />were collected from this depth for each of these borings. <br />Soil samples were collected from the Geoprobe borings using a 2 -inch outside diameter, 4 -foot long core <br />barrel, fitted with a clean, single use, acetate liner. Soil samples were collected from the hand auger <br />borings by driving a sampling sleeve into the soil with a slide hammer. The soil sampling equipment was <br />cleaned prior to boring the next hole and the cutting shoe and sampling sleeve were cleaned prior to <br />collecting each sample by washing them in a solution of laboratory -grade, non -phosphate detergent and <br />deionized water, and double -rinsing with de -ionized water. <br />During the soil sampling, the Geoprobe° core barrel was driven continuously in four -foot intervals to <br />between 16 feet and 40 feet bgs. After the core barrel was driven four feet, the core barrel was withdrawn <br />and the sample was removed. The sample liner was extracted from the core barrel and used for geologic <br />logging and field observations. A new unused acetate liner was placed in the core barrel and the process <br />was repeated. All soil samples were logged according to the Unified Soil Classification System (USCS). <br />Geologic logs were prepared containing field observations including soil type, estimated moisture <br />content, photoionization detector (PID) measurements, and the presence of staining or odor. The geologic <br />logs are included in Appendix B. Each soil sample selected for potential laboratory analyses was cut from <br />the liner. The soil samples were retained, undisturbed, in the liners. The liners were sealed at the ends <br />with Teflon`" sheeting, capped, and labeled. The samples were stored in a cooler chilled with Blue Ice <br />and delivered under chain -of -custody procedures to Excelchem Environmental Labs (Excelchem) of <br />Roseville, California. The samples were analyzed using U.S. EPA and California approved methods. <br />4.3.2 Groundwater Sampling <br />Groundwater samples were collected from two of the Geoprobe° borings, B-3 and B-5. The borings were <br />completed to termination and then new PVC casing and riser were placed in the open boreholes. <br />Groundwater flowed hydrostatically from the formation into the inlet screen. A groundwater sample was <br />retrieved from within the screen with a length of clean, 3/8 -inch diameter poly tubing with a check valve <br />at the bottom. The tubing was pumped up and down by hand to draw groundwater up the tubing. The <br />iA� CONDOR <br />