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__ <br /> Alk <br /> 1117 Lone Palm Avenue, Suite 201 <br /> Modesto, California 95351 <br /> 209-579-2221 <br /> Fax: 209-579-2225-2225 <br />: I <br />:I <br /> Drilling Activities <br /> This task includes mobilization to the site, advancing up two vertical soil borings, collecting soil <br /> samples, and abandoning the borings. Estimated locations of the proposed soil borings are shown on <br /> j Figure 2. <br /> I <br /> k The proposed soil borings will be advanced using a hollow-stem auger equipped drill rig to <br /> approximate depths of 25 to 35 feet bgs. Drilling will be conducted by a State-licensed C57 drilling <br /> company. A field geologist will be present to log drill cuttings and collect soil samples from the <br /> I borings. Descriptions of soil types encountered and sample collection intervals will be recorded on <br /> f well logs. Soil samples will be collected at five-foot intervals using an auto-hammer. Each soil <br /> sample will be field screened with a PID meter or similar instrument and up to two samples from <br /> each boring, based on field observations (i .e. odor, discoloration, PID readings), will be placed in a <br /> E cooler with ice and submitted for laboratory analyses. An ATC field geologist will complete <br /> lithologic logs for each boring in general accordance with ASTM Method D 2488-90. _ <br /> c <br /> Soil Sample Analyses <br /> Select soil samples collected during the advancement of the proposed soil borings will be analyzed <br /> for gasoline ranged organics (GRO), known also as TPHg utilizing EPA Method 801513; benzene, <br /> toluene, ethylbenzene, and total xylenes (BTEX), methyl tertiary butyl ether (MTBE), tertiary butyl <br /> alcohol (TBA), di-isopropyl ether (DIPE), ethyl tertiary butyl ether (ETRE) tertiary amyl ether <br /> (TAME), 1 ,2-dichloroethane ( 1 ,2-DCA), and 1 ,2-dibromoethane (EDB) utilizing EPA Method <br /> 826013; CAM 17 Metals utilizing EPA Method 6010; and hexavalent chromium by EPA Method <br /> 7199. <br /> In addition, an estimated three soil samples will be collected for geotechnical analyses ; one sample <br /> from the water bearing portion of the identified clay unit, one sample from the silty water bearing <br /> unit, and one sample from the sandy water bearing unit. Each soil sample will be collected in brass <br /> sleeves or acetate sleeves, whichever method is best suited to capture an undisturbed sample. Each <br /> sample will be analyzed for soil porosity using API Method RP40 or ASTM Method D425M, soil <br /> permeability by EPA Method API RP40, particle size distribution by ASTM Method D4464M, <br /> hydraulic conductivity by ASTM Method D5084, and total organic carbon using the Walkley-Black <br /> method. The data obtained from these analyses will be useful regarding remedial design <br /> considerations. <br /> i <br /> Groundwater Sampling <br /> I <br /> A groundwater sample will be collected from groundwater monitoring well MW3 . This well was <br /> selected since analyte concentrations associated with groundwater samples collected from this well <br /> are usually elevated and this well is located within the general vicinity of the proposed ozone sparge <br /> remediation well locations. Prior to collecting a groundwater sample, the depth to water will be <br /> measured inside the well and a minimum of three casing volumes will be purged from the well. The <br /> ph, temperature, and electrical conductivity will be monitored during each successive purge volume. <br /> s:\environmental\62596\reports\workplan for soil sampling 4 <br />