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3.2.1 Soil Sampling and Analysis During drilling, undisturbed soil samples will be collected at 5-foot intervals using a modified California split-spoon sampler lined with two-inch diameter by six-inch long stainless steel sample sleeves. A field geologist will log each of the undisturbed soil samples for hydrogeologic and lithologic characteristics according to the Unified Soil Classification System and screen each sample for organic vapors using a photoionization detector (PID). Based on field observations and PID measurements, at least three soil samples per boring will be submitted for laboratory analysis. These soil samples should include those collected at approximate depth of the pottom of the former UST (15 feet below sub-grade), at the groundwater ' table interface (i.e., capillary fringe), and at the total depth of the soil borings?Additional sail samples may be submitted for analysis, if required to adequately characterize the site. Field observations and sample selection will be reviewed with the EHD hazardous materials inspector, prior to sample submittal to the lab. The soil samples will be sealed with Teflon film and plastic end caps, labeled, packaged in an iced cooler, and transported with chain-of-custody documentation to a state of California-certified hazardous waste testing laboratory for analysis. Each of the soil samples will be analyzed on a standard turn-around time for TPH-as-gasoline and BTEX by EPA Method 8021 B/8015M or 8260B, and for MTBE, DIPE, ETBE, TAME, TBA and 1,2-DCA by EPA Method 82608. 3.2.2 Groundwater Sampling and Analysis From all three soil borings, groundwater samples will be collected from the boreholes using two- inch - � _.. _. inch diameter polyvinyl chloride (PVC) temporary wells. The temporary wells will consist of 20 feet of flush-threaded and machine-slotted (0.020Wndwa" ter,-, ih}vy (Vs 'en spanning approximately ten feet above and ten feet below the depth of static `Blank PVC casings will thread into the tops of the well screens and extend to the surface. Neither a sand pack nor a well seal will be installed in the temporary wells. Prior to groundwater sampling, the temporary wells will be purged of at least three casing volumes using a bailer. During purging, groundwater temperature, pH and electrical conductivity will be recorded to evaluate the stability of these parameters. Once the groundwater in the temporary wells is purged and recharged to at least 90% of its original groundwater column thickness, the groundwater samples will be collected. r 10