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PSI Project Number:0575-1504-R1 <br /> ounGuggenheim—Stockton, CA <br /> August 16, 2019 <br /> Page 3 <br /> 3 SCOPE OF WORK—SUBSURFACE SAMPLING <br /> This section describes the proposed methodology to conduct a subsurface investigation at the site. The <br /> objective of our proposed work is to establish protocols for conducting an investigation that will provide <br /> data for completion of the Subsurface Investigation Report for the subject property and to assess <br /> whether former practices at the former gas station have impacted the subject property. <br /> 3.1 PRE-FIELD ACTIVITES <br /> A minimum of three working days prior to performing the field services, PSI will mark the site and call <br /> Underground Service Alert to notify utilities and public service agencies of the proposed excavation. <br /> Additionally, a private utility locator will clear the proposed sampling locations, as well attempt to <br /> identify whether USTs are still present associated with the former gas station. <br /> To complete any environmental subsurface evaluation, the San Joaquin County Environmental Health <br /> Department (SJEHD) requires that a Workplan be prepared and then approved by the SJEHD prior to <br /> the investigation being conducted. Additionally, a drilling permit is required by the SJEHD. PSI will <br /> receive approval of this Workplan and obtain a drilling permit from the SJEHD prior to initiating field <br /> work. <br /> 3.2 SOIL SAMPLING <br /> Five soil borings have been selected in the most likely location of former USTs, islands, and piping, <br /> associated with the former gas station. Two of these soil borings will be in the area of the future USTs <br /> to provide background information on the soil in this area. The five soil borings in the area of the former <br /> gas station will be drilled to a depth of 40 feet bgs. The proposed locations of the soil borings are <br /> presented on Figure 2. Boring locations will be verified using a hand-held Global Positioning System <br /> (GPS) device. <br /> Soil borings will be advanced using a Geoprobe direct-push drill rig. Prior to drilling, the boring will be <br /> cleared for utilities with a hand auger. The drilling services will be provided by a C-57 licensed well <br /> drilling contractor. Soil samples will be collected by PSI field personnel working under the supervision <br /> of a State of California Professional Geologist. Soil samples will be collected in acetate tubes <br /> continuously with samples collected at 5-foot intervals for possible analyses. If field observations <br /> indicate petroleum hydrocarbon impacted soil at a depth other than 5-foot intervals, that soil sample <br /> will also be collected for possible analyses. Field observations will be noted, which include olfactory <br /> and visual signs of impact, as well as soil screening using a photo-ionization detector (PID). One soil <br /> sample from each boring will be selected for analyses with the soil sample selected based on PID <br /> readings and field observations. If no evidence is noted, the soil sample collected from the bottom of <br /> each boring will be selected for analyses. Additionally, a soil sample will be collected for analyses at 15 <br /> feet in the two borings drilled in the area of the future USTs. Following drilling, all borings will be <br /> backfilled according to SJEHD requirements. <br /> www.intertek.com/building <br />