ARCHIVED REPORTS XR0003742 - Laserfiche WebLink

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of the piping trench soil samples at 1 5 fbg The soil samples were collected at 3 5 and 6 fbg with a hand auger and did not contain detectable levels of TPH and benzene In late May 1995, Well RW-iA was drilled and installed within the former UST complex A total of 2,090 yd' of soil were removed from the site during tank removal and tank installation activities Fugro estimated that the volume of petroleum hydrocarbons contained in this soil was 1,106 gallons Fugro estimated the total volume of petroleum hydrocarbons removed by SVE, hand bailing, and vacuum truck extraction was 2,720 gallons The total volume of petroleum hydrocarbons recovered was 3,826 gallons In January 1997, Wells MW-6, MW-7, and MW-8 were installed on-site and at off-site locations (Plate 2) In addition to the well installation, one soil boring was drilled near RW-lA to assess the vertical extent of petroleum hydrocarbons in the soil in the source area Soil samples collected from MW-6 and MW-7 did not contain detectable levels of Total Purgeable Petroleum Hydrocarbons (TPPH), benzene, and MTBE Soil samples from MW-8 were ND for TPPH, benzene, and MTBE at the intervals of 5, 10, and 15 fbg The sample collected at 20 fbg contained 960 ppm TPPH, 15 ppm benzene, and 10 ppm MTBE Quarterly ground water monitoring has been performed at the site since the first quarter of 1995 Depth to ground water has ranged from 6 5 fbg to 12 5 fbg on-site over the last four years Ground water flow direction has been variable at the site but has shown some tendency toward the north Hydraulic gradient has ranged from 0 001 to 0 015 Shell began collecting ground water samples from five domestic wells and one irrigation well located south of the subject site during the summer of 1997 Locations of these wells are shown on Plate 2 Results of the sampling events for these wells are summarized on Table 4 and briefly detailed below The Caltrans irrigation well was sampled on September 5, 1997 through a sampling port in the well head Ground water samples contained a concentration of 280 ppb TPPH and 160 ppb toluene During the August 29, 1997 ground water sampling event in the domestic well at 2452 Country Club Boulevard, a ground water sample was collected from the sample port and did not contain detectable levels of TPPH, BTEX and oxygenate compounds Ground water samples collected from the sample ports on the domestic wells located at 2454 Country Club Boulevard and 2456 Country Club Boulevard on September 26, 1997 did not contain detectable levels of TPPH, BTEX, and oxygenate compounds 240-0783 4