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Geologicat Technics Inc. Page 11 <br /> Interim Remedial Action Plan <br /> Project No.723.2 <br /> March 7,2005 <br /> observations to provide sediment descriptions. A maximum of two soil samples shall be <br /> obtained from the 60 — 70 feet bgs depths for laboratory analysis. Soil samples will be <br /> collected in 6.0-inch brass liners using a 2.0-inch modified California split spoon sampler. <br /> All soil samples will be sealed with Teflon sheets, capped, labeled and placed in a cooler at <br /> 4° Celsius for transport to the laboratory following Chain of Custody protocol. <br /> A field observation process will be used to gather additional information through noting <br /> sediment type, especially grain size and clay content; moisture content; visible evidence of <br /> contamination, i.e., color change due to reduction of iron or discoloration from hydrocarbons <br /> and other pollutants, and any readings above background levels on an organic vapor meter <br /> (OVM). The OVM is a field portable photo ionization detector that uses a 10.0 eV lamp to <br /> detect compounds with ionization potential below 10.0 eV (hydrocarbon range). <br /> 3.2.1.3 Soil Laboratory Analysis <br /> GTI proposes testing the soil samples (2) for the following compounds: <br /> 0 Purgeable aromatic hydrocarbons (BTEX) by EPA method 8020. <br /> • Total petroleum hydrocarbons as gasoline by method 8015, modified. <br /> The samples will be submitted to a California certified laboratory. The detection limits for <br /> these compounds are listed below. <br /> Detection Limits: I BTEX TPH-G <br /> Soil ( /K ) 13.0 11,000 <br /> 3.2.1.4 Extraction Well Installation <br /> The extraction well will be constructed using schedule 40 PVC casing with flush threads. <br /> Before installing the bentonite seal the well will be surged with a clean surge block or bailed <br /> with a clean steel bailer to achieve maximum filter pack density. A weighted bentonite <br /> transition seal will be installed above the sand filter pack and allowed to set for thirty <br /> minutes. A surface seal will be achieved by pumping a neat cement grout (augmented with< <br /> V <br /> 4% bentonite) through the augers, as they are withdrawn to ensure that an integral grout seal <br /> is achieved. The well will be secured with locking watertight cap encased in flush mounted <br /> traffic rated well box (plumbing to treatment system to follow). The proposed construction <br /> details of the well are included in the following table. <br /> Well Dia./TD I Screen Slot Sand Pack Trans.Seal Grout Seal <br /> EW-2 4'77T 67 - 77' 0.020" #12 sand 65-77' 62 - 65' 62'-surface <br /> 3.2.1.5 Extraction Well Development <br /> After the well sealing materials have set (>24 hours) the new wells will be developed (using <br /> mechanical surging and pumping methods) until a clear stream of water is obtained. All <br /> development water will be containerized in 55 gallon DOT approved containers and stored <br /> on site until their disposition can be arranged. <br /> V <br /> V <br />