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Ge ofogic ar Te c&tks Inc. %WI Page 2 Soil Investigation Report Arctic Ice(D St.) Project No.691.2 a. December 10, 1998 north end of the former tank, a second approximately 15 feet north of the former tank and the third approximately 15 feet south of the former tank. 2.1 Soil Sampling Procedure `' On December 1, 1998, Geological Technics and V&W Drilling of Rio Vista, license no. (C57 # 720904), mobilized to the site to drill the proposed boreholes_ The drilling was performed using a hollow stem auger drill rig owned by V&W. w.. Soil samples were collected for geological and analytical purposes. Soil sample cores (18- inch long cores) were collected continuously in S13-1 to a depth of 30 feet and then at five- foot intervals down to 40 feet bgs. In SB-2 & 3, soil samples were collected at five-foot intervals down to 40 feet bgs. Ray Kablanow logged the boreholes and collected the soil samples. A boring log describing the types of sediment encountered, using the USCS and field observations, was made during the drilling process. Soil samples were collected in 6.0-inch brass liners using a 2.0 inch modified California split spoon sampler. All soil samples were sealed with Teflon, capped +•• with plastic end caps, labeled and placed in a cooler at 4° Celsius for transport to Sherwood Labs following Chain of Custody protocol. In SB-1, soil samples were submitted to the lab at 5-foot intervals, starting at 9.5 feet bgs. Of the 18-inch core collected, the bottom 6-inch core tube was submitted to the lab for analysis. In SB-2 & 3, a screening process was used to select soil samples for testing. The field 'r observation noted the following: • sediment type, especially grain size and clay content • moisture content 1 L, ,�. • visible evidence of contamination, i.e., color change due to reduction of iron or �� discoloration from hydrocarbons and other pollutants t: t CD • readings above background on a organic vapor meter (OVM) E—I+�,c,,,w The OVM is a portable photo ionization detector that uses a 10.0 eV lamp to detect compounds with ionization potential below 10.0 eV (hydrocarbon range). Upon collection of the final sample, each borehole was abandoned by a neat cement grout containing less the 4% bentonite. The grout was pumped, by pressure grouting methods using a tremie tube. The surface was capped with a concrete plug finished flush to grade. 2.1.2 Soil Laboratory Analyses Based on field screening observations, eight soil samples from SB-1 and five soil samples `r from SB-2 & 3 were tested. Sherwood Laboratories of Hilmar (State Certified Laboratory #1400) analyzed samples. Samples will be tested for diesel range petroleum hydrocarbons (Total Extractable Petroleum Hydrocarbons (TEPH) - Diesel) by EPA method 3540/8015m. The detection limits for these compounds &e listed below. A Chain of Custody will be completed for all samples collected and tracked to ensure sample integrity. etectionLimits: - ai mg g