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1 <br /> Q <br /> 1 ASSOCIATE S I N C . <br /> benzene and xylenes. Lead was detected in all soil samples, but the concentrations were <br /> consistent with background concentrations of lead for the San Joaquin Valley (less than 15 ppm). <br /> t Analytical results of soil samples are summarized in Table 1. Laboratory data sheets and chain-of- <br /> custody documentation is presented in Appendix A. <br /> ' 223 Soil Transport and Disposal <br /> The excavated backfill material was immediately manifested and transported to Forward Inc. <br /> ' landfill in Stockton by Bob Evans Trucking on September 11, 1998. Copies of non-hazardous <br /> waste manifests and weight tags for the disposed soil are contained in Appendix B. <br /> ' 224 Excavation Backfill <br /> The excavation was backfilled on September 11, 1998 with clean pea gravel from sixteen feet bgs <br /> to five feet bgs. The remaining five feet was backfilled with crushed concrete to the surface. The <br /> excavation was backfilled by Bob Evans Trucking under the supervision of ATC personnel. <br /> ' 3.0 SUBSURFACE INVESTIGATION ACTIVITIES <br /> . To investigate the extent of impacted groundwater and determine the groundwater gradient at the <br /> site, four soil borings were advanced in the vicinity of the former 1,000-gallon UST and three of <br /> the borings were completed as groundwater monitoring wells. All field activities were performed <br /> in accordance with ATC's Revised Workplan for Soil Excavation and Additional Subsurface <br /> Investigation at Inland Paint, 117 West Harding Way, Stockton, California, dated July 6, 1998. <br /> This workplan was approved by PHSlEHD with minor modifications. <br /> ' 331 Soil Boring Advancement and Sampling <br /> Drilling was conducted by V & W Drilling (State C57 license no. 720904) utilizing a hollow stem <br /> auger drill rig. Four soil borings SB2, MW I, MM2, and MW3 were advanced and borings MW 1, <br /> MW2, and MW3 were completed as groundwater monitoring wells. A field geologist logged drill <br /> ' cuttings and soil samples utilizing the Unified Soil Classification System. Descriptions of soil <br /> types encountered and sample collection intervals are included on the boring/well construction <br /> logs contained in Appendix C. <br /> ' Cored soil samples were collected at five-foot intervals or significant changes in lithology in <br /> borings MW 1 and MW2 from 5 feet to 43 feet bgs and from boring SB2 from 40 feet to 65 feet <br /> ' bgs. Continuous core soil samples were collected from boring SB2 from 65 feet to 70 feet bgs to <br /> better define the soil lithology at the bottom of boring SB2. The cored samples were collected <br /> using a 2-inch diameter split-spoon sampler containing three brass tubes. The cored samples and <br /> ' drill cuttings were characterized for soil type, moisture content, and visual evidence of petroleum <br /> hydrocarbons. A photoionization detection meter (PID) was used as a field screening device for <br /> the detection of petroleum hydrocarbon vapors in drill cuttings and cored samples. Drill cuttings <br /> were temporarily stored on site in 55-gallon DOT approved steel drums. <br /> w:1172951rep \ulsuraii.doc 3 <br />