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in conjunction with the removal of the underground fuel tanks. A <br /> summary of the analytical laboratory results is given in Table' 1. <br /> Proposed Investigation Methods <br /> ERM-West has been requested to undertake additional work to <br /> accomplish the following objectives 1) to determine ."clean zones" ., <br /> within the current excavation where further excavation is not <br /> necessary, and 2) to better define the extent of the contamination. <br /> The investigation will consist of digging slots into the sloped <br /> sidewalls of the existing excavation at six locations. The <br /> approximate location of the slots are identified on Figure 1. The slots <br /> will be initiated by excavating a trench approximately two feet below <br /> the floor of the existing excavation pit at six locations. The floor of the <br /> existing excavation is approximately fifteen feet below' grade. <br /> Samples will be taken from the trenches and analyzed on-site to <br /> determine the need for further excavation. Soil samples 3i will be <br /> collected by pounding a six-inch brass tube into native soil at each of <br /> the trench locations. Each sample will be collected near the toe of the <br /> slope of the excavation. <br /> Each slot will be created by excavating radially in each location to <br /> create a trench that will extend to the 'top of the slope of the <br /> excavation wall. A soil sample will be collected with a backhoe <br /> bucket approximately 17 feet below the grade and immediately below <br /> the top of the slope in each slot. The slot will be deepened by <br /> excavating to a depth of approximately 32 to 35 feet below grade. <br /> Another sample will be collected from each slot at 32'to 35 feet below <br /> grade directly below the top of the slope of the existing excavation. <br /> Following sample collection, the,slot will be backfilled with�the soil <br /> which was removed from that slot. <br /> Samples will be analyzed for Total Petroleum Hydrocarbons (gas and .. <br /> diesel) and Benzene, Toluene, Xylene, and Ethylbenzene (BTX&E).as <br /> shown in Table 1. <br /> Table 1 <br /> Sample Preparation&Analytical Methods - . . <br /> and Target Detection Limits for Soil Analyses <br /> Soil Preparation Analysis MDL <br /> TPH EPA Method 3550 EPA Method 8015 mod. 1:mg/kg <br /> BTX&E EPA Method 5030 EPA Method 8020 g/kg <br />