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1 ' <br /> 16, SECTION 4 <br />' SUMMARY AND RECOMMENDATIONS <br />' This section presents a summary and recommendations derived from activities of the current <br /> investigation <br /> f <br />' 4.1 Summary <br /> Five soil borings were advanced and identified as soil borings B-1, B-2, B-3, B-4, and <br /> monitoring well MW-1 Analytical results for BTEX compounds were non-detect for all <br /> submitted soil samples Analytical results of soil samples obtained from borings B-1, B-2, and <br /> MW-1 indicated that petroleum hydrocarbon compounds were not present Petroleum <br />' hydrocarbon compounds were however detected in soil samples obtained from borings B-3 and <br /> B-4 <br /> Soil boring B-3 was advanced at an angle for access below the building retaining wall and <br /> foundation At a depth of 20-feet at boring B-3 (sample B3-20') analytical results for TEPH as <br /> diesel and TEPH as motor oil indicated concentrations of 6,900 mg/Kg and 7,000 mg/Kg, <br /> respectively Analysis of soil sample B3-25', obtained at a depth five feet greater, indicated <br /> that petroleum hydrocarbons were not present at detectable concentrations Vertical <br /> distribution of petroleum hydrocarbon impacted soil at this location is estimated at 3-feet thick, <br /> occurring at a depth between 19 and 22 feet <br /> Soil boring B-4 was advanced at an angle for access below the concrete electrical vault <br /> Petroleum hydrocarbon compounds were detected in soil samples obtained between the depths <br /> of 15 and 19-feet Between these depths TEPH concentrations ranged from 12,000 to 169 <br />' mg/Kg for diesel, from 8,300 to 730 mg/Kg for motor oil, and from 460 µg/Kg to ND for <br /> gasoline It should be noted that reported concentrations of TPH as gasoline exhibited <br /> characteristics of a heavier hydrocarbon than the gasoline standard The soil sample obtained <br />' from a depth of 23-feet indicated that petroleum hydrocarbons were not present at detectable <br /> concentrations Vertical distribution of petroleum hydrocarbon impacted soil at boring B-4 has <br /> been estimated at 6 5-feet thick, occurring at a depth between 14 and 20 5 feet <br />' n well MW-1 obtained on August 9 and October 10, 1996, <br /> Water samples from monitoring gu <br />' were analyzed for BTEX, MTBE, and several fractions of petroleum hydrocarbons All <br /> results for these analyses were reported as not detected <br /> r <br />' Geologic information obtained during this investigation indicates that a clay barrier is present <br /> at a depth from 30 to 35 feet The relatively low transmtsstvity of this 3 to 5-foot thick clay <br /> unit may limit the vertical migration of petroleum hydrocarbons into the existing groundwater <br /> table <br /> 7 <br /> 1 <br />