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r <br /> 12 August 1991 <br /> GeoAudit -V 30-34E2-1.6 <br /> Page 2 of 5 <br /> Classification System (see Boring Logs) . <br /> On 4 June 1991, the top of each well casing was surveyed relative to a <br /> temporary benchmark and the depth to ground water was measured. Because <br /> free product was recovered in 2-inch PVC bailers in M11-1 and in MW-2, <br /> water samples were not collected for analysis. <br /> FINDINGS <br /> Both MW-2 and MW-3 penetrated an upward-fining arkosic sand body from <br /> total depth to approximately .40 feet. This sand, which was saturated <br /> below 45 feet, is moderately weathered and oxidized but contains little <br /> clay. Strong hydrocarbon odor: were detected in samples at 40 and. 45 <br /> feet .in Loth wells, and TPH levels ranged from 20 ppm to 1100 ppm in <br /> those samples. Benzene ranged from 0.43 to 9.2 ppm. The laboratory <br /> report (WtST No. 2556, 24 May 1991) and chain of. custody form are <br /> attached. <br /> Above 40 feet, the two wells penetrated slightly different.material. MW- <br /> " - 2 encountered mostly sandy silt to a depth of 16 feet, whereas MW-3 <br /> penetrated clay, clayey silt, and clayey sand to a depth of 20 feet. No <br /> hydrocarbon odor was detected in this interval in MW-2, but moderate <br /> odor was present in MW-3. TPH levels were low to moderate, ranging up to <br /> 280 ppm at 35 feet in 11W-2. Benzene was 1.5 ppm or less. In general, <br /> BTE&X concentrations correlate positively with TPH concentrations. <br /> Moderately well-graded sand is present in MW-2 from 10 to 16 feet. This <br /> interval consists of sitly,clay and clayey sand in MW-3. No hydrocarbon <br /> odor was detected. <br /> A layer of free product (gasoline) measuring 6.125 inches thick in Moi-1 .. <br /> and 7.25 inche's:thick in MW-2 "was present when the wells were monitored <br /> on 4 June 1991. No free product was present in MW-3. <br /> The adjusted depth to ground ;nater ranges between 46.42 feet in MW-2 and <br /> 46.52 feet in MW-3. The surveying data (Table I) indicate 'that the local <br /> water table is essentially flat; with a slight hydraulic gradient of no <br /> more than 0.002 (0.1 degree) to the south (Figure 3) . <br /> ___-CONCLUSIONS <br /> 1. The results of this investigation indicate that both soil and <br /> ground water are impacted. Off-site migration. cannot be ruled out <br /> at this time. <br />,ice <br />