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Septic Tank Area- 3 to 4 borings Northern Interior Anomaly— 1 to 2 borings Southeastern Corner/Southern Interior Anomaly— I to 2 borings For the purposes of this assessment, all borings will be completed on-site. No off-site borings will be completed unless data collected from this assessment indicate the need to complete future borings. Concrete coring to allow drilling access may be necessary where thick concrete is encountered. Borings will be completed using a Geoprobe (direct push) rig. Soil samples will be collected at approximately 5-foot intervals (beginning at 5 feet bgs) in each boring, or as may be determined based on on-site field observations, drilling conditions and proximity to potential sources of impact (e.g., current and former operations, as identifiable). Groundwater samples will be collected using disposable bailers from each temporary monitoring well (e.g., slotted PVC) installed within each deep boring. Continuous or interval soil samples will be collected from surface to total depth. Discrete selected soil samples will be collected via appropriate sampling procedures for laboratory analyses based on physical observations, olfactory, visual staining and field monitoring of soil vapor using a photo-ionization meter. Groundwater is assumed to be encountered at approximately 27 feet bgs based on the prior investigation. PEI will survey stabilized groundwater elevations to obtain the groundwater gradient/direction of flow across the site. The soil and groundwater samples will be sealed and placed in a cooler for preservation and delivery to an off-site laboratory under standard chain-of-custody methods. The proposal and cost estimate assume the shallow borings can be performed using Geoprobe-type direct-push equipment; PEI also assumes residual soil cuttings will be minimal from the shallow borings. The field work is planned for completion within two days depending upon drilling conditions (i.e., using a Geoprobe, soil type, etc.) and whether some of the work can be performed concurrently. When completed, the soil boring locations will be abandoned and permanently sealed in accordance with the requirements of the San Joaquin County. Generally, the borings will be backfilled with neat cement and finished with a concrete or asphaltic concrete seal to match surface surroundings. 4.0 LABORATORY ANALYSIS Depending upon drilling conditions and the total number of borings completed, PEI proposes submitting up to 32 soil matrix (generally four per soil boring ) and 8 groundwater samples (one per temporary groundwater monitoring well) for analysis. Fewer or additional samples may be collected as time and drilling conditions allow. The samples will be analyzed by California DTSC-certified laboratory(s), in accordance with EPA approved Methods. The soil samples will be selected based on visual and olfactory field observations, and potentially based on depth and location. The soil matrix and groundwater samples will be analyzed for total petroleum hydrocarbons by carbon chain analysis (TPH- Remediation Pilot Study Workplan Pinnacle Environmental,Inc. 248 Industrial Drive,Stockton,CA Page 5