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t (YVAT4L A S S O C I A T E S I N C SCOPE OF WORK Workalan Preparation ATC has completed the well permit applications for the proposed subsurface investigation. The permit applications, one for the site and one for the City of Stockton right-of-way property, and necessary fees (checks #286 & 287) are attached to this workplan. ATC will also schedule field personnel and equipment, notify Underground Services Alert to locate underground utilities as required, and perform any other necessary field preparation and job start-up activities. Advancement of Two Soil Borings To try and determine the horizontal extent of soil and groundwater contamination, one soil boring will be advanced approximately 120 feet southwest of the former UST to a depth of approximately 57 feet bgs and completed as a shallow groundwater monitoring well. One angle soil boring will be completed to first encountered groundwater, estimated to be approximately 42 feet bgs. The angle boring will be advanced immediately southwest of the former UST, under the on-site building. Once a grab groundwater sample has been collected from the angle soil boring, the boring will be tremie grouted to the surface with neat cement. The proposed boring/well locations are shown on Figure 2. The two borings will be advanced using an 8-inch hollow stem auger equipped drill rig. A field geologist will be present to log all drill cuttings and soil samples. Descriptions of soil types encountered and sample collection intervals will be recorded on boring/well logs. Soil Sample Collection and Analysis Soil samples will be collected at five-foot intervals or changes in lithology, field screened with a PID, placed in a cooler with ice. At least two soil samples from each of the two borings will be submitted for laboratory analysis.. Selected soil samples will be analyzed for TPHg, TPHd, TPHss, and BTEX. All drill cuttings will be drummed and stored on-site pending laboratory results. Groundwater Monitoring Well Construction Details One soil boring will be completed as a monitoring well to a depth of approximately 57 feet bgs. The monitoring well will be constructed of 2-inch inside diameter schedule 40 PVC well screen and casing. A 0.020-inch well screen slot and #2112 mesh sand pack will be used. Neat cement will be used to seal the well in accordance with California Well Standards (December 1981). To protect the integrity of the well, locking, a water-tight well plug will be installed on the well and a water-tight wellhead labeled "monitoring well" will be concreted over the well. The top of casing of the new wellhead will be surveyed and tied into the existing groundwater monitoring wA 172951reportslwkp 1299.doe 3