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0 ON <br /> -. holes or cracks. Ground water was encountered in the tank <br /> cavity at approximately 7 feet below grade. Following the <br /> removal of the tanks, soil and ground water samples were <br /> collected from the tank cavity. Three gran samples of <br /> water in the tank cavity were collected and composited to <br /> one sample for laboratory analysis. In addition, two soil <br /> samples were collected, one from the side wall of the waste <br /> oil tank excavation pit, at about 7 feet below the surface, <br /> and the other from beneath the product lines, at about <br /> 4 feet below the ground surface. <br /> Laboratory analysis indicated the presence of total <br /> - petroleum hydrocarbons (TPH) in the composite water sample <br /> _.. at 30 parts per million (ppm) , and benzene, toluene, and <br /> xylenes concentrations (BTX) at 1.6, 3.0, and 5.3 ppm, <br /> -- respectively. Analysis of one soil sample collected from <br /> the wall of the waste oil tank excavation pit showed total <br /> hydrocarbon concentrations of 61 ppm, with no detectable <br /> _. levels of benzene, toluene, and xylenes. Polychlorinated <br /> biphenyls (PCB) and halogenated volatile organic compounds <br /> (HvCC) were not detected at the method detection limit. <br /> Laboratory analysis of the soil sample obtained below the <br /> product lines indicated TPH concentrations of 2.0 ppm with <br /> benzene, toluene, and xylenes at concentrations of 0.22, <br /> 0.34, and 0.29 ppm, respectively. <br /> 2.2.2 Preliminary Site Investigation - 1986 <br /> In August 1986, four monitoring wells (MW-1 through MW-4) <br /> were installed onsite by KEI. Each of the four wells was <br /> completed to a depth of 20 feet below grade. Gasoline odor <br /> was noted in soils between 1 and 7 feet below grade while <br /> drilling MW-3 and MW-4. No soil samples were collected or <br /> analyzed because of the shallow ground water conditions and <br /> well construction. <br /> At the time of water sampling, no free product was observed <br /> �. in any of the wells. Petroleum odor was noted in the <br /> samples collected from MW-3 and MW-4. Dissolved-phase <br /> hydrocarbons were detected only in the water samples from <br /> mW-3 and MW-4 (Kaprealian, 1986) . <br /> 2.2.3 Additional Site Investigation - 1987 <br /> Based on the results of the preliminary investigation work, <br /> four additional monitoring wells (MW-5 through MW--8) were <br /> installed by KEI in January 1987. Monitoring Well MW-5 was <br /> installed onsite, while the other three wells were <br /> installed offsite, as shown in Figure 2. <br /> 3 <br />