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Y s ✓i 'Vow, V <br /> 25 October 1996 <br /> AGE-NC Project No. 96-0259 <br /> Page 2 of 3 <br /> 2.3. GROUND WATER DEPTH <br /> Review of Lines of Equal Depth of Water Wells - Fall 1993 published by the San Joaquin County <br /> Flood Control and Water Conservation District suggests that the water-table surface beneath the site <br /> occurs at a depth of approximately 20 to 25 feet below surface grade (bsg). The uppermost ground <br /> water flows in a unconfined aquifer. With depth, the aquifer becomes more semi-confined due to the <br /> presence of mixed heterogeneous layers of sediments. <br /> Review of ground water monitoring well data from nearby sites suggests that regional ground water <br /> flow is towards the northeast. <br /> 3.0. SCOPE OF WORK <br /> 3.1. DRILLING AND SAMPLING <br /> AGE proposes to initially advance two soil probe borings to a depth of approximately 20 feet bsg. <br /> Probings will be advanced using a Geoprobe soil probing unit, and soil samples collected at a depth <br /> of 20 feet bsg. Probings will be advanced near two former UST locations. Proposed soil probe <br /> boring locations are illustrated on Figure 2. <br /> 3.2. EQUIPMENT DECONTAMINATION <br /> All probe rods and sampling tools used for sample collection will be thoroughly rinsed with clean <br /> water after washing with a solution of Alconox. <br /> 3.3. LABORATORY ANALYSIS <br /> Selected samples will be analyzed for total petroleum hydrocarbons quantified as gasoline(TPH-g), <br /> volatile aromatics (benzene, toluene, ethylbenzene, and xylenes: BTE&X) and methyl-tertiary butyl <br /> ether(MTBE) in accordance with EPA methods 8015m and 8020/602 beneath the former gasoline <br /> UST location, and will be analyzed for oil and grease and halogenated volatile organics in accordance <br /> with EPA method 5520 and 8010 beneath the former waste oil UST location. Laboratory reports of <br /> from the soil analysis, testing methods, laboratory quality assurance/quality control (QA/QC) reports <br /> and sample chain-of-custody documentation will be presented in a report with the findings and <br /> recommendations. <br />