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1 v <br /> 0 <br /> 1 y <br /> •1 A S S O C I A T E S I N C <br /> On September 21, 1998, an ATC geologist supervised the advancement of five soil borings, SB7 <br /> through SB 11, from 5 to 31 feet bgs A site plan showing soil boring locations is included as <br /> Figure 2 Soil samples were collected at five-foot intervals and grab groundwater samples were <br /> collected from each boring Samples were analyzed for petroleum hydrocarbons and elevated <br /> 1 concentrations of petroleum hydrocarbons were detected in soil and groundwater samples <br /> 2.0 METHODS AND PROCEDURES <br /> 1 To evaluate the extent of impacted groundwater and determine the groundwater r dient at the <br /> 1 <br /> site, three soil borings were advanced in the vicinity of the former USTs and completed as <br /> groundwater monitoring wells All field activities were performed in accordance with ATC's <br /> Workplan for Additional Subsurface Investigation at Ripon Unified School District, 304 North <br /> Acacia Avenue, Ripon, California, dated January 15, 1999 This workplan was approved by <br /> PHS/EHD on January 21, 1999 with minor modifications <br /> 1 221 Soil Boring Advancement and Sampling <br /> Drilling was conducted on January 27, 1999 by V & W Drilling (State C57 license no 720904) <br /> utilizing a hollow stem auger drill ng Soil boring MW2 was advanced to 45 feet bgs using <br /> continuous core methodologies to collect undisturbed soil samples and obtain more exact <br /> lrthological data The soil samples from soil borings MW1 and MW3, advanced to 35 feet bgs, <br /> 1 were collected at five foot intervals or significant changes in lrthology Soil borings MW1, MW2, <br /> and MW3 were advanced and completed as groundwater monitoring wells A field geologist <br /> logged drill cuttings and soil samples utilizing the Unified Soil Classification System Descriptions <br /> 1 of soil types encountered and sample collection intervals are included on the boring/well <br /> construction logs contained in Appendix A <br /> The continuous core soil samples were collected from a 3-inch diameter split spoon sampler by <br /> driving a 2-inch diameter brass tube with a rubber mallet into the undisturbed soil sample The <br /> soil samples from borings MWl and MW3 were collected at five-foot intervals or significant <br /> 1 changes to lithology using a 2-inch diameter split-spoon sampler containing three brass tubes The <br /> cored samples and drill cuttings were characterized for soil type, moisture content, and visual <br /> 1 evidence of petroleum hydrocarbons A photoionization detection meter (PID) was used as a <br /> field screening device for the detection of petroleum hydrocarbon vapors in drill cuttings and <br /> cored samples Drill cuttings were temporarily stored on site in 55-gallon DOT approved steel <br />' drums <br /> L.2 Soil Sample Analysis <br />' Selected soil samples were placed on ice, and transported under chain-of-custody to Sequoia <br /> Analytical (FLAP #1210) of Redwood City, California for analysis All soil samples were <br />' analyzed for total petroleum hydrocarbons as gasoline (TPHg), total petroleum hydrocarbons as <br /> diesel (TPHd), and benzene, toluene, ethylbenzene, and xylenes (BTEC utilizing EPA 8015 and <br /> w 1130991reports%sumwel cim 2 <br />