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• Ms Margaret Lagroio August 11,2004 Subsurface Assessment Report Project No 2033-15600-01 Joe's Truck Plaza, 15600 South Harlan Road,Lathrop,CA Page 5 The lowermost intact sleeve of soil from each sample interval was retained for possible chemical analysts The ends were covered with TeflonTM sheets and tight fitting plastic caps Each sample was appropriately labeled, identified on a chain-of-custody form, and then placed in an ice-chilled cooler A diagram illustrating the piston sampler utilized by Gregg In Situ, Inc is included in Appendix B Sampling intervals, lithologic descriptions, and PID screening results are included on the CPT logs in Appendix B, and on the borehole logs in Appendix C Soil Boring and Monitoring Well Construction A Stratus geologist was on-site to oversee Gregg Drilling and Testing, Inc (C-57 #408165) of Martinez, California, complete the drilling activities on May 14, 2004 The well boring was advanced using a drill rig equipped with 10-inch diameter hollow stem augers The boring was completed as groundwater monitoring well MW-7, as described below Soils were classified on-site using the Unified Soil Classification System Boring logs detailing soil stratigraphy are presented in Appendix C Copies of the dnlling permits are also included in Appendix C The initial 5 feet of the boring was hand cleared to reduce the possibility of damaging underground utilities Soil samples were collected from the boring using a California- type, split-spoon sampler equipped with three precleaned brass tubes The ends of the bottom-most, intact tube from each sample interval were lined with TeflonTM sheets, capped, and sealed Each sample was labeled, placed in a resealable plastic bag, and stored in an ice-chilled cooler Strict chain-of-custody procedures were followed from the time the samples were collected until the time the samples were relinquished to the laboratory Additional soil from each sampled interval was placed and sealed in plastic bags to allow the accumulation of VOC vapors within the airspace in the bags A portable PID was used to measure VOC concentrations from each sample In parts per million by volume (ppmv) PID results are included on the boring log presented in Appendix C Monitoring well MW-7 was constructed in the boring using 4-inch diameter PVC well casing The well screen consisted of 15 feet of 0 02-inch diameter factory slotted casing, installed from approximately 4 to 19 feet bgs A filter pack of RMCTM #3 sand was placed in the annular space around the well from the bottom of the casing to approximately I foot above the top of the well screen Approximately 1 foot of bentonite was placed on top of the filter pack and hydrated with clean water to provide a transition seal for the well The remaining annular space was filled with neat cement up to surface grade A traffic rated vault box was placed over the well, and a watertight locking cap P Voe's Truck Plaza\Reports\CPT report 08-2004 doc