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' • • Limited Phase II Environmental Site Assessment Work Plan 600 E.Main Street,Stockton,CA ' Page 2 depth of 30 feet bgs to investigate the potential for petroleum hydrocarbon contamination of the soils at depth. The proposed boring locations are shown on Figure 3. ' 3.1 SITE PREPARATION t Condor will complete drilling and encroachment permit applications and obtain the required permits from the San Joaquin County Environmental Health Department (EHD) and the City of Stockton Public Works Department (PWD), respectively, prior to the fieldwork. Condor will schedule and coordinate all field activities through the property owner, the driller, the EHD, and the PWD as needed. The proposed boring locations will be (narked with white paint and Underground Services Alert(USA) will be notified at least 72 hours in advance of the fieldwork to locate and identify underground utilities in and near the ' work area. The client is responsible for notifying Condor of any known utilities. 3.2 GEOPROBE BOREHOLES ' The boreholes will be advanced using a Geoprobe percussion hammer driven sampler equipped with a 1.75-inch O.D., 4-foot long, core barrel, fitted with a clean, single use, polyethylene liner. A licensed C57 drilling contractor will drill the boreholes under the supervision of a Condor geologist. The soil ' samples will be screened for the presence of organic vapors in the field with a photoionization detector (PID). Following completion of the sampling, the boreholes will be filled with neat cement. The cement will be tremied into the borehole to avoid bridging. The PWD will likely require that the impacted portions of the concrete sidewalk (approximately 2.5-foot squares) be saw-cut, removed, and replaced with new concrete. This work will be completed subsequent to the drilling activities. ' 3.3 SOIL SAMPLING Continuous core samples will be collected from the four borings advanced next to the suspected UST. The soil retained inside each core barrel will be logged according to the Unified Soil Classification ' System. Geological logs will be prepared containing field observations including soil type, estimated moisture content, PID measurements, and the presence of staining or odor. Two soil samples will be selected from each borehole for laboratory analyses to include total extractable petroleum hydrocarbons ' (TEPH), total petroleum hydrocarbons quantified as gasoline (TPH-G), benzene, toluene, ethyl benzene, and total xylenes (BTEX.), methyl tertiary-butyl ether (MTBE), and total lead. Soil samples will be selected at intervals suggestive of soil contamination based on field screening. If there is no evidence of ' contamination, samples will be collected from 10 feet and 20 feet below the ground surface. The soil samples will be retained, undisturbed, in the liners. Each sample end will be covered with Teflon® sheeting, the ends sealed with plastic end caps, and labeled. All soil samples selected for laboratory ' analyses will be stored in a cooler chilled with ice and delivered under chain-of-custody procedures to a California Certified Laboratory and analyzed using U.S. EPA Methods and California-approved methods under quality assurance measures. ' Prior to use, the soil sampling equipment will be decontaminated by washing in a solution of laboratory- grade, non-phosphate detergent and hydrocarbon-free water, and double rinsing with hydrocarbon-free water. The soil cuttings will be placed in 55-gallon drums, sealed, labeled, and left on-site to await ' disposal pending results of the laboratory analysis. 1 ' is CONDOR