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Stockton Promenade—N. Edison3freet USTs& Utility Corridors • Page 8 Underground Storage Tank Removal Report June 8,2009 WKA No,7345.09 During exploratory test pit excavation activities, Mr. von Flue of the SJEHD indicated that soil ' sampling was not necessary under the UST abandonment permit as the petroleum piping had been previously abandoned in-place. At the request of Mr. Roberto Cervantes of the RWQCB, WKA advanced two of the exploratory test pits (EP-I and EP-4) to depths of 15 and 18 feet bgs to collect grab groundwater samples for laboratory analysis. Because groundwater was not encountered at the maximum depths of these exploratory test pits, deeper-interval soil samples were collected instead. ' Subsurface conditions encountered consisted primarily of imported fill material and building rubble to depths of approximately 2 to 8 feet bgs. Native soils encountered below this interval consisted ' primarily of silty fine-grained sand to depths of 18 feet bgs. After sampling or visual identification of soil conditions, each test pit was backfilled with the material excavated from that test pit, the location was flagged, soil descriptions were logged on field forms, and the location was marked for future identification. ' 4.0 DIRECT-PUSH BORINGS ' During UST removal and exploratory test pit excavation activities, groundwater was not encountered at depths less than 18 feet bgs. Because petroleum hydrocarbon affected soils were ' identified in this area extending to a depth of at least 18 feet bgs, Mr. Cervantes of the RWQCB requested that a grab groundwater sample be collected from the former UST area. Per the RWQCB's request, WKA advanced and sampled 4 direct-push borings (EB-1 through EB-3) at ' the site around the previous UST locations on March 26, 2009 (Figure 3). Soil boring EB-1 was in the general location of exploratory test pit EP-6 that was previously excavated to observe soil ' conditions but was not sampled. Soil boring EB-2 was in the general location of exploratory test pit sample EP-5, adjacent to an abandoned water line northeast of the removed USTs. Soil ' boring EB-3 was in the general location of the center of the former UST area(Figure 3). The soil borings were advanced by V&W Drilling of Isleton, California. Soil samples were ' collected for lithologic descriptions and/or chemical analysis from 2-to 4-foot intervals at each sampling location. Each of the borings were advanced to depths ranging from 12 to 28 feet bgs, ' to collect shallow grab groundwater samples for laboratory analysis. Soil samples were collected, logged, and screened with a PID to measure concentrations of total VOCs in soil- vapors. Groundwater was encountered at depths ranging from 11 to 23 feet bgs in the three boring locations,however these depths correspond to depths from ground surface conditions