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A daily health and safety tailgate meeting will be conducted at the beginning of each field day to <br /> discuss potential hazards encountered during drilling and sampling activities. <br /> Utility Clearance <br /> The locations of the seven proposed soil borings will be marked in the field in white paint. Before <br /> commencing drilling activities, 811 Underground Service Alert (USA North) will be notified no less <br /> than 72 hours prior to drilling activities who, in turn, will contact local utility companies to identify the <br /> locations of underground utilities in the proposed work areas, as appropriate. As-built utility drawings <br /> showing the locations of aboveground and underground utilities will be reviewed, if available. A <br /> private utility locating company will also be contracted to survey the boring areas for potential <br /> underground utilities. Where underground utilities or structures are present beneath proposed boring <br /> locations, proposed borings will be relocated to unobstructed areas, as deemed appropriate. <br /> FIELD WORK <br /> After obtaining the necessary permits, developing a safety plan and clearing boring locations of <br /> utilities, drilling and associated soil and groundwater sampling will commence. Proposed boring <br /> locations for soil and grab groundwater sampling are presented on Figure 2. <br /> Drilling and Sampling <br /> The borings will be advanced using a hand auger for the first 5 feet below ground surface (bgs) <br /> and then to the total depth using a direct-push drill rig. Based on a review of historical groundwater <br /> monitoring reports for leaking UST cases in the Site vicinity, we understand that depth to <br /> groundwater ranges from approximately 17 to 30 feet bgs and the groundwater flow direction <br /> ranges from northeast to southeast. Based on this information, we recommend installing one of the <br /> borings west (up gradient) and adjacent to the former USTs and sump areas, one cross-gradient <br /> and north of the soil AOC, and the remaining five borings in the presumed down-gradient <br /> (northeast to southeast) directions. Two soil samples will be collected in the vadose zone from <br /> each boring where physical signs of contamination, such as odors, staining, or elevated <br /> photoionization detection (PID) meter readings are observed or at 5-foot intervals. At least one <br /> sample will be collected between 0 and 5 feet bgs and between 5 and 10 feet bgs from each <br /> boring. One groundwater sample will be collected from each boring where groundwater is first <br /> encountered. The borings will be advanced to first-encountered groundwater, which is anticipated <br /> at approximately 15 to 30 feet bgs. All borings will be backfilled with neat cement to grade. Borings <br /> will be patched using concrete or other materials to match existing grade. <br /> Ninyo&Moore 1 180 East Weber Avenue,Stockton,California 1403488001 1 May 23,2019 3 <br />