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r � � Imlog"I7ecknfcs Inc Page 3 Feasibility Study&Investigation Work Plan Cardoza(Main St) Project No 662 2 Apnl l4, 2004 rThe borings will be drilled using an 8-mch outside diameter continuous flight hollow stem auger The boreholes will be advanced to a depth of 45 feet below the ground surface (bgs) The expected depth to groundwater in this area is 30 feet below grade, based on information ' from the previous site work Soil cuttings will be containerized in DOT approved 55-gallon steel drums and held on site rpending disposal 2.2 Soil Sampling ' Soil samples will be collected for geological evaluation at five-foot intervals Boring logs will be developed by a professional geologist under the supervision of a registered geologist The logs will be prepared using the U S C S and field observations to provide sediment descriptions A single soil sample from the capillary fringe shall be obtained from each boring for laboratory analysis Soil samples will be collected in 6 0-inch brass liners using a 2 0-inch modified California split spoon sampler All soil samples will be sealed with Teflon sheets, capped, labeled and placed in a cooler at 4° Celsius for transport to the ' laboratory following Chain of Custody protocol A field observation process will be used to gather additional information through noting sediment type, especially grain size and clay content, moisture content, visible evidence of ' contamination, i e , color change due to reduction of iron or discoloration from hydrocarbons and other pollutants, and any readings above background levels on an organic vapor meter (OVM) The OVM is afield portable photo ionization detector that uses a 10 0 eV lamp to detect compounds with ionization potential below 10 0 eV (hydrocarbon range) 2.3 Soil Laboratory Analysis GTI proposes testing at a minimum the capillary fringe sample soil sample from both of the ' boreholes (2 samples) Soil samples will be tested for the following compounds • Purgeable aromatic hydrocarbons (BTEX) by EPA method 8020 ' • Total petroleum hydrocarbons as gasoline by method 8015, modified • The fuel oxygenates MTBE, D1PE, TAME, ETBE & TBA by EPA method 8260 The samples will be submitted to a California certified laboratory The detection limits for these compounds are listed below A Chain of Custody will be completed for all samples collected and tracked to ensure sample integrity etection emits: xygenates of µg gTO 1varies , 2.4 Monitoring Well Installation The monitoring wells will be constructed using schedule 40 PVC casing with flush threads Before installing the bentonite seal the well will be surged with a clean surge block or bailed with a clean steel bailer to achieve maximum filter pack density A granular bentonite transition seal will be installed above the sand filter pack and hydrated with clean tap water A surface seal will be achieved by pumping a neat cement grout (augmented with < 4% bentonite) through the augers, as they are withdrawn to ensure that an integral grout seal is achieved The wells will be secured with locking watertight caps encased in flush mounted traffic rated well boxes The proposed construction details of the two monitoring wells are included in the following table 1 1