ARCHIVED REPORTS XR0001840 - Laserfiche WebLink

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At least one boring will be installed to verify the litho-logic interpretation presented by the CPT The boring will be drilled to first encountered groundwater. Because the boring will be continuously logged, analytical soil samples probably will not be collected. Depending on the _analytical results from the CPT assessment, the boring-may be completed as a vapor extraction well The CPT assessment also may indicate that additional borings are necessary. Borehole(s) not used for vapor wells will be grouted with cement/bentonite. Borings converted into vapor wells will be completed similar to the groundwater monitor wells described below. Wells: Based on the previous data, several monitor wells will be necessary to assess the "zero-line" of petroleum hydrocarbon impacted groundwater. The number and locations will be proposed after evaluating the CPT data. Each monitor well will be constructed of 2-inch PVC casing/screen within an 8-inch diameter borehole. Each well will be screened from approximately 5 feet above, to approximately 15 feet below, groundwater. The filter pack will be placed to approximately 2-feet above the top of the screen. Either bentonite chips or a fine sand will be used to protect the filter pack from grout infiltration. The remaining borehole will be grouted with a cement/bentonite grout The casing will be sealed with locking compression style caps, and the wells will be finished inside traffic rated vault boxes Task 3: Monitor Well Development Each monitor well will be developed by surging indigenous water in and out of the well screen. Surging will be performed during construction of the well by using a surge-block. After surging, a bailer will be used to remove sediment laden water from the monitor well Purge water will be stored in 55-gallon drums and left onsite pending review of disposal options. Any tools which will be used in more than one of the wells will be either steam cleaned or washed with an Alconox solution and rinsed with distilled water Task 4: Sampling and Analysis A minimum of 48-hours after redevelopment of the wells, each of the wells (new and existing) will be sampled Prior to sampling, the depth to groundwater and the thickness of the immiscible layer (if any) will be measured Wells which do not have a product layer will be purged of approximately three well volumes of water After purging, a clean disposable bailer will be used to collect the sample from the top of the groundwater Water from each well will be transferred into three HCl preserved 40-m1 VOA bottles supplied by the analytical laboratory. The bottles will be labeled, logged on a churn-of-custody, and immediately placed in an iced cooler The three (one per well) water samples will be analyzed for TPHg and BTEX by EPA Method 5030/8015M plus 8020 at Western Environmental Science and Technology (WEST) WEST is certified by the State of California Department of Toxic Substances Control (DTSC) for the requested analyses A copy of the analytical report will be sent directly to Ms. Linda Turkette (SJCEHD) by the laboratory 4