ARCHIVED REPORTS_REMEDIAL INVESTIGATION REPORT 2000

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Treadwell&Rollo Site History This site was reportedly formerly a delta island,reclaimed during the 1920s, and used for steel fabrication until the early 1970s. Figure 3 shows the approximate locations of former buildings. Currently there are no structures on site, although approximately half of the site is capped with a steel-reinforced concrete slab (Figure 3). Previous Investigations Prior to the 1999 Treadwell & Rollo investigation, no soil or groundwater sampling had been performed at Area 11. Nineteen soil and three groundwater samples were collected by Treadwell & Rollo at the locations shown on Figure 3. A hand auger was used to collect 2-foot deep soil samples at boring locations 11B-2, 11B-4, 11B-10, and 11B-12. A direct push rig advanced soil borings 11B-1, 11B-3, 11B-5, 11B-6, 11B-7, 11B-8, 11B-8A, 11B-9, and 11B-11 to depths that ranged between 2 and 17 feet. Concrete refusal was encountered at boring locations 11 B-5 and 11B-8 and only shallow soil samples were obtained. Refusal due to dense soil conditions occurred at boring locations 11B-1, 11B-7, and 11B-8A, and a geoprobe rig was used to push through the soil at these locations to collect groundwater samples. Soil samples were collected at 1 to 6.5 feet bgs at borings 11 B-1, 11 B-7, and 11 B-8A. Groundwater samples were bailed from borings 11B-1, 7, and 8A. TPH-d was detected in all soil samples, at concentrations ranging from 1.4 to 49 mg/kg. TPH- mo was analyzed in eleven soil samples, ranging from nondetect to 280 mg/kg. Toluene was detected at 9.7 mg/kg in one of eighteen samples analyzed.No semivolatile organic compounds were detected. Total lead was detected in all soil samples,ranging from 5.6 to 1,300 mg/kg. No VOCs were detected in groundwater. TPH-d was detected in two of three samples at 0.12 and 0.16 mg/l. Diethyl phthalate was detected in two samples at 0.029 and 0.11 mg/1. No significant metals concentrations were detected. 8 25970309.DGD 24 August 2000