ARCHIVED REPORTS XR0001804 - Laserfiche WebLink

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r" January 7, 1993 Working To Restore Nature ARCO Station No 760, Lads, California I o Subcontract an underground line locating service to mark underground lines with respect to the proposed boring/well locations and contact Underground Service Alert at least 48 hours before drilling to delineate public utility lines at the site I o Drill one soil boring beyond the northwest corner of the site, one boring north of boring B-14, and one boring near the northeast corner of the site The proposed locations are shown on Plate 2 The borings will be terminated at approximately 50 feet bsg or when two consecutive soil samples with photoionization detector (PID) readings below 10 parts per million by volume are recorded, whichever is encountered first We estimate terminating the borings at approximately 40 - 55 feet below grade The borings will be converted to 4-inch-diameter vapor-extraction wells, if warranted The screened zone for all vapor-extraction wells will be based on residual hydrocarbon concentrations previously detected in the area and PID readings of soil samples collected in the field o Collect relatively undisturbed soil samples at 5-foot tntervals or lithology changes from the ground surface to the total depth of each boring and classify soil samples according to the Unified Soil Classification System • o Submit appropriate soil samples to a State-certified laboratory for analysis of TPHg and TPHd and BTEX using EPA Methods 8015/5030 (modified) and 8020, respectively o Collect four soil samples from the drill cuttings to be composited at the laboratory 1 and analyzed for TPH9, TPHd, and BTEX using previously stated methods Results of analyses will be used to evaluate disposal options Drill cuttings will be stored at the ARCO station We will provide ARCO's subcontractors with the laboratory data needed for disposal of drill cuttings and water from the decontamination of drilling equipment M o Prepare a Preliminary Investigation and Evaluation Report (PIER) to the SJCPHS- EHD if residual hydrocarbons in soil are delineated If hydrocarbons in soil are not delineated during this scope of work, the PIER will be postponed pending additional assessment 1 The work will be performed in accordance with the methods and procedures described in RESNA's Work Plan No 38048-3W, dated April 23, 1990, and Tri-Regional Board Staff Recommendations for Preliminary Evaluation and Investigation of Underground Tank Sites (California Regional Water Quality Control Board, Central Valley Region, August 1990), • 082occar 38048-7 5