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The alignment of the approximately 660-foot long sanitary sewer lateral will be identified by a private utility locator as noted in Section 6.1. The six proposed 5-foot deep soil gas probe locations along the sewer lateral alignment are shown on Figure 8. The depth of the sewer lateral within the Site will be assessed by measuring the depth using the sewer cleanout vaults using a tape measure prior to implementing the field work. The 5-foot deep soil gas samples proposed for two locations associated with the petroleum hydrocarbon release are shown on Figure 9. The proposed three cumulative soil gas assessments will be conducted in general accordance with the July 2015 DTSC Advisory and will consist of soil gas samples from probes installed with a direct push Geoprobe. The soil gas samples will be analyzed for VOCs in accordance with EPA Method 8260 by an on-site mobile laboratory. The soil gas probes will be permanently installed and secured with a well box for future sampling events. Probe destruction methods will be provided in an additional work plan upon completion of onsite activities. 6.4.1 Proposed Shallow Soil Gas Sample Probe Installation Methods The soil gas probes will be installed with dual-tube direct push equipment using a Geoprobe. This technique will allow a soil gas probe to be purged and sampled approximately two hours following the final installation of the probe. The soil gas probes will be secured and completed to prevent infiltration of water or ambient air into the subsurface and to prevent accidental damage or vandalism. The tubing will be marked at the surface to identify the probe location and depth. A gas-tight valve or fitting for capping will be affixed to the sampling tube. To allow for the subsurface to equilibrate to representative conditions, each probe will not be purged or sampled for at least two hours following probe installation. The soil gas probes will be permanently installed and secured with a well box for future sampling events. Probe destruction methods will be provided in an additional work plan upon completion of onsite activities. Sampling and Analysis Workplan Tracy Corners Shopping Center 3225 North Tracy Boulevard Tracy,California 95376 Partner Project Number SM14-129814 Docket Number HAS-VCA 14/15-108 August 15,2016 Page 24