ARCHIVED REPORTS_XR0006919- CASE 2

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I ` 28 April 2005 AGE-NC Project No 97-0351 Page 3 of 11 the vicinity of the West UST area at the western edge of the site and in the vicinity of the on-site plating shop Locations of the soil probe borings are illustrated on Figure 2 TPH-g,BTEX,and methyl tertiary-butyl ether(MTBE)were detected in soil samples collected from the probe borings at concentrations as high as 3,700 mg/kg(TPH-g,P 1-10) Hydrocarbon-impacted soil associated with the West UST area appeared to be of limited lateral extent TPH-g was detected in four of ten grab ground water samples collected from the West UST area at concentrations ranging from 84 micrograms per liter(µg11)to 44,000 µg11 Vanous BTEX compounds were detected in six of ten samples analyzed at concentrations ranging from 0 60 µg/1 to 7,800 µg11 Hydrocarbon-impacted soil in the vadose (unsaturated) zone associated with the West UST area within San Jose Street was limited to a narrow zone from depths of approximately 5 feet to 15 feet bsg immediately surrounding the UST The detection of MTBE in soil samples collected from probe boring P1 indicated the release of gasoline to be relatively recent,possibly within the past 20 years Gasoline-impacted ground water is present around the West UST area Total petroleum hydrocarbons quantified as diesel (TPH-d)was detected at concentrations up to 6,600 µg/1 from four of five grab ground water samples analyzed from the western property boundary The subject property has no documented use of TPH-d To determine the lateral extent of the hydrocarbon impact to soil and ground water associated with the West UST and the potential impact from the Texaco facility to the subject property, additional soil probe borings were advanced at the site under the supervision of the EHD Hydrocarbon- impacted water associated with the West UST was limited to the vicinity of the former tank location, while diesel-impacted water was documented along the western edge of the property boundary On 01 and 05 December 1997, a total of ten soil probe borings (P16 to P25) were established surrounding the East UST area TPH-g and BTEX were detected in soil samples collected from the probe borings at concentrations as high as 2,100 mg/kg and 14 mg/kg (xylenes), respectively Hydrocarbon-impacted soil associated with the East UST area appeared to be limited to the former dispenser area (southern edge of Lindsay Street), and to a depth of 16 feet to 17 feet bsg, in the saturated soil below the ground water table TPH-g was detected in six of eleven grab ground water samples collected from the East UST area at concentrations ranging from 53 µg/1 to 100,000 µg/1 BTEX was detected in eight of eleven samples analyzed at concentrations ranging from 0 55 µg/I to 1,700 µg/1 In January 1998, four ground water monitoring wells were installed near the West UST area to quantify the hydrocarbon concentration in ground water and determine the direction of ground water flow Results ofthe well installation and subsequent sampling delineated the dissolved hydrocarbons Advanced GeoEnvironmentel,Inc