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Ms.Amber Ginorio,RWQCB January 30,2023 <br /> Addendum to Sampling and Analysis Plan <br /> 2478 Wilcox Road,Stockton,California <br /> Page 6 <br /> Task 213: Soil Borings SB-1 through SB-5 and Soil Sampling <br /> A licensed well driller will advance the five soil borings located in the vicinity of the leach <br /> field, in the presence of a Stratus Geologist, using a limited access direct-push drill rig, or <br /> equivalent,equipped with 3.25-inch diameter hollow steel drive rods. The soil borings will <br /> be advanced to just before encountering groundwater (capillary fringe). Groundwater is <br /> presumed to occur at approximately 55 to 65 feet bgs,based on available information from <br /> nearby sites in GeoTracker. The actual boring depths will depend on the depth of first <br /> encountered groundwater. <br /> Soil samples will be collected continuously from the total depth the air knife advances to <br /> the total depth of each boring, using acrylic tubes. The Stratus geologist will utilize the <br /> entire tube for lithologic analysis in accordance with the Unified Soil Classification System <br /> (USCS) and will screen the soils in the field for volatile organic compounds (VOCs)using <br /> a photo-ionization detector(PID). The bottom-most 6-inch-long section of every five feet <br /> and any observable sections containing stratigraphic contacts, will be cut off and retained <br /> for chemical analysis. The ends of the samples will be lined with Teflon sheets, capped, <br /> labeled,placed in a re-sealable plastic bag, and stored in an ice-chilled cooler. Strict chain- <br /> of-custody procedures will be followed from the time the samples are collected until the <br /> time the samples are relinquished to California Laboratory Services (CLS). Stratus will <br /> submit one soil sample from approximately one foot below the total depth the air knife <br /> advances, as well as select soil samples(e.g. high PID readings and from contacts between <br /> fine- and coarse-grained sediments), for laboratory analysis. The exact number of samples <br /> submitted for laboratory testing will be determined at the time of the investigation. <br /> Once the soil samples have been collected, neat cement will be tremied into the boring <br /> using the drive rods. After allowing for settlement of the neat cement, the upper two feet <br /> will be completed to ground surface with concrete to match the surrounding area. All <br /> sampling equipment will be cleaned in an aqueous non-phosphate solution cleanser,rinsed <br /> with tap water, and rinsed a second time with deionized water to prevent cross- <br /> contamination between sample intervals. <br /> Task 2C: Soil Boring SB-6 and Soil and Groundwater Sampling <br /> A licensed well driller will advance soil boring SB-6 located adjacent to the damaged outlet <br /> lateral identified on January 19, 2023, using a limited access direct-push drill rig, or <br /> equivalent, equipped with 3.25-inch diameter hollow steel drive rods. Soil samples will be <br /> collected continuously from the total depth the air knife advances to the total depth of the <br /> boring, using acrylic tubes. The Stratus geologist will utilize the entire tube for lithologic <br /> analysis in accordance with the USCS and will screen the soils in the field for VOCs using <br /> a PID. Soil sampling of SB-6 will be conducted following the same procedures described <br /> in Task 2B. Once the boring has encountered groundwater, a grab groundwater sample <br /> will be collected. The boring will then be advanced an additional 15 feet to a total depth <br /> T:\Stockton Propeller\Addendum to SAP\SM_Addendum to Sampling and Analysis Plan.docx STRATUS <br />