Laserfiche WebLink
r <br /> were detected in the samples from 15 feet (0.5 mg/Kg) and 64 feet (0.069 mg/Kg). No TPH <br /> as gasoline detections were measured in any of the samples collected. <br /> 1 <br /> 3.2.2 Bloassess►nent <br /> Three soil samples were collected from boring SB-1 for bioassessment These samples were <br /> collected in order to investigate the feasibility of bioremediation at the site. Results of the <br /> bioassessment (Appendix E) indicated that bioremediation may be successfully performed to a <br /> depth of 50 feet. <br /> r3.2.3 Geotechnical Testing <br /> Four relatively undisturbed soil samples were collected from boring SB-1 for geotechnical <br /> testing. These samples were tested to determine the subsurface soil conditions. These results <br /> (Appendix F) may be used in the design of a remediation system at the site. <br /> r <br /> 4.o Summary and Conclusions__.. <br /> Soil borings SB-I and SB-2 were drilled and sampled in order to assess the current soil <br /> conditions and provide a means for developing appropriate remedial options for the site. <br /> The August 1995 chemical data suggest that TPH as diesel has impacted two local areas of <br /> � gg P <br />' soil within the vadose zone (Figure 5). The areas are at depths of 15 feet and 64 feet and <br /> appear to be confined to within about 30 feet of the tank pit laterally. Figures 3 and 4 <br /> illustrate vadose zone conditions around 1993, based on historical information. No further <br /> rlateral migration of TPH or BTEX is indicated from 1993 to 1995. Comparison of 1992-1993 <br /> and 1995 data (Figures 3, 4, and 5) indicate that petroleum hydrocarbon concentrations have <br /> decreased over time. <br /> The concentration of TPH as diesel in the deep vadose zone has apparently decreased <br /> approximately 40 percent at a depth of approximately 60 feet (2,000 mg/Kg to 1,200 mg/Kg) <br />' and over 85 percent in the shallow impacted zone (130,000 mg/Kg to 15,000 mg/Kg at 15- <br /> foot depth). This is based upon comparison of the results of borings MW-4 and SB-1. This <br /> reduction is probably due to in-situ bioremediation by indigenous micro-organisms, as <br /> indicated by the results of the bioassessment. <br /> r <br /> M7I11-20-95/VDBF195-OM7 6 <br /> 1 <br />