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e <br /> f tit e <br /> Mr. Jerry Lile(DTSC) <br /> Page 4of7 <br /> Soil Sampling and Analysis <br /> On May 24, 2006 Ground Zero collected soil samples from three locations agreed upon with <br /> DTSC. The locations were intended to duplicate previous locations where background levels of <br /> copper were present. The previous X/Y coordinate system was used to identify sample locations <br /> since the white paint from 2003 was still visible. Samples were collected at locations 25WAS, <br /> 80EAS and 130E/3S. All samples were collected from the current ground surface to <br /> approximately 2-3 inches below grade. The samples were collected with a trowel and placed in <br /> sample bags for transport to the laboratory under chain of custody protocol. Sampling locations <br /> are shown on Figure 3. Field notes are included in Attachment A. <br /> Each sample was analyzed by State-certified Argon Laboratories (ELAP No. 2359) for total <br /> copper using EPA Method 6010B. Background levels of copper were detected in samples <br /> 25WAS-SURF (63 ppm) and 130E/3S-SURF (42 ppm). Sample 80E/4S-SURF exhibited a <br /> somewhat elevated level of total copper(120 ppm). <br /> Each sample was then subjected to a DI-WET extraction and the extract analyzed for soluble <br /> copper by EPA Method 6020A. The samples with background levels of total copper each had a <br /> water-soluble copper level of 0.012 ppm in the extract. Sample 80E/4S-SURF contained 0.050 <br /> ppm copper in the extract. <br /> Laboratory reports and chain of custody documentation are included in Attachment B. Analytical <br /> results, including pertinent results from previously collected samples are summarized in Table 3. <br /> EVALUATION OF RESULTS <br /> The current and previous data were evaluated to estimate the background levels of total and <br /> water-soluble copper at the site and the potential for anthropogenic copper to threaten aquatic <br /> life. <br /> Background and Elevated Copper Concentrations in Site Soil <br /> Based upon the totality of the soil data, we conclude that the background level of total copper in <br /> site soils ranges from approximately 35 — 85 ppm. The background level of water-soluble <br /> copper is approximately 0.012 mg/1 (ppm) in extract and, accounting for the 10-fold dilution in <br /> the DI-WET analysis, 0.12 mg/kg(also ppm)in soil. <br /> Elevated concentrations of total copper were identified at 2 locations within the area previously <br /> excavated (0/3S-SURF @ 908 ppm and 80E/4S-SURF @ 120 ppm). In addition, 2 unexcavated <br /> sample locations east of the work area contained somewhat elevated total copper concentrations <br /> (151E/3S-SURF @ 150 ppm and 166 E/3S-SURF @ 170 ppm). These last 2 samples would not <br /> G:\GROUNDZE\MARINA\VjllageWest\Aquatoxrpt.doe <br />