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October 4, 2018 <br />San Joaquin County Environmental Health Department <br />Page 2 of 3 <br />Reference: Soil and Groundwater Investigation Work Plan <br />Soil Borings <br />Stantec will observe the advancement of direct push borings B-1 and B-2 at the locations depicted on <br />Figure 1. The proposed soil borings will be advanced to 20 feet bgs. The borings will be advanced using a <br />truck-mounted rig equipped with a two-inch outer diameter Macro Core® sampling device. Soils will be <br />continuously logged by a Stantec field geologist using the Unified Soil Classification System (USCS), <br />working under the supervision of a California Professional Geologist. Soil samples may be collected for <br />potential laboratory analysis based on photoionization detector (PID) readings and other field observations. <br />Soil samples will be collected at four-foot intervals from the continuous core liner and sealed with Teflon® <br />sheeting and plastic caps. The soil samples will then be labeled and placed on ice in an insulated container <br />for delivery to a state-certified laboratory under appropriate chain-of-custody (COC) documentation. These <br />soil samples will be analyzed for gasoline-range organics (GRO), benzene, toluene, ethylbenzene, and total <br />xylenes (collectively BTEX), methyl tertiary butyl ether (MTBE), tertiary butyl alcohol (TBA), ethyl tertiary <br />butyl ether (ETBE), diisopropyl ether (DIPE), tertiary amyl methyl ether (TAME), and naphthalene using <br />Environmental Protection Agency (EPA) Method 82606; and for total lead using EPA Method 6010B. <br />Grab Groundwater Sampling <br />Grab groundwater samples will be collected from each of the borings. After collection of the soil samples, <br />Stantec will supervise the collection of grab groundwater samples from the borings using a truck-mounted <br />rig equipped with a two-inch diameter modified HydroPunch® (or similar) sampler. Prior to sampling, a <br />water level meter will be used to confirm that the drive rods do not contain water. The sampler will be driven <br />to approximately five feet below groundwater and retracted three feet to expose a disposable schedule-20 <br />polyvinyl chloride (PVC) screen and allow groundwater to enter the HydroPunch® sampler. The water <br />samples will be collected by lowering a clean %%diameter stainless steel or disposable bailer through the <br />drive rods to groundwater. The groundwater will be bailed from the drive rods and decanted from the bailer <br />into appropriate sample containers. The samples will be labeled, placed on ice, and transported to a state- <br />certified laboratory under appropriate COC documentation. The grab groundwater samples will be <br />analyzed for GRO, BTEX, MTBE, TAME, TBA, DIPE, ETBE, and naphthalene by EPA Method 8260B. <br />Following collection of the soil and grab groundwater samples, each boring will be tremie grouted from total <br />depth to surface grade with neat cement grout. <br />Waste Handling <br />Any soil and waste generated during the advancement of the soil borings will be placed in Department of <br />Transportation approved 55-gallon drums on site pending characterization and disposal. <br />Prior to disposal, a four-point composite soil sample will be collected from the soil drums and placed on ice <br />in an insulated container for delivery to the laboratory. The soil sample will be analyzed for GRO, BTEX, <br />and MtBE by EPA Method 8260B; for DRO by EPA Method 8015; and for total lead by EPA Method 6010B. <br />Design with community in mind