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Work Plan for Limited Site Investigation Proposed Distribution Center Stockton, California February 22, 2022 Terracon Project No. NA227001 Responsive Resourceful Reliable 4 The six 70-foot borings will be completed as temporary sampling wells (TSWs). Construction details of the TSWs are described further in Section 2.6.2. Two soil and one groundwater samples will be collected from each TSW boring and submitted for laboratory analysis. The depth of soil samples collected from the TSW borings will be determined in the field based on PID readings, changes in lithology, or at the capillary fringe. One soil sample will be collected from each 15-foot soil boring and submitted for laboratory analysis. The depth of soil samples collected from the 15-foot soil borings will be determined in the field based on PID readings or changes in lithology. Additional soil samples may be collected from the soil borings at intervals exhibiting a change in lithology, and/or from the bottom of the boring. These soil samples will be placed on hold for potential contingent analyses if recommended based on review of the initial analytical results. The soil samples will be collected and placed into laboratory-prepared containers. The containers will be labeled and placed on ice in a cooler which will be secured with a custody seal. The samples and completed chain-of-custody forms will be transported to the selected analytical laboratory for analysis within 10-day turnaround following receipt of the samples by the laboratory. Temporary Sampling Wells and Groundwater Sampling Upon the completion of drilling activities, the soil borings will be converted to TSWs for groundwater sampling. The TSW locations are included on the Site Diagram (Exhibit 1). The TSWs will be constructed with the following materials: 5 feet of 1-inch diameter, 0.010-inch machine slotted poly-vinyl chloride (PVC) well screen with a threaded bottom cap; and A 1-inch diameter, threaded, flush-joint PVC riser pipe to surface. A water level indicator will be used to determine depth to groundwater after construction of the temporary groundwater monitoring wells. One groundwater sample will be collected from each of the TSWs using disposable tubing and dedicated baler sampler or equivalent. The groundwater sample containers will be labeled with the project number, date, time, and sample number and placed in a chilled cooler immediately after sampling. The sample containers will be subsequently transported to Pace Analytical, a California state-certified laboratory, under strict chain-of-custody procedures. Boring Abandonment Terracon will schedule the backfilling inspection with the SJCDEH no later than 48 hours prior to planned field work activities to ensure the availability of an SJCDEH representative. Additionally, Terracon will confirm the field work date and inspection time with the inspector 24 hours prior to field work.