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1 • <br /> LEVINE•FRICKE <br /> PH. soil samples collected for this investigation had pH <br /> readings ranging from 7. 6 to 8. 3 units. Five samples had a pH <br /> of 8 . 1, three samples had a pH of 8.0, and three samples had <br /> a pH of 7 .8 . <br /> CONCLUSIONS <br /> Concentrations of arsenic and copper detected in soil samples <br /> collected during this investigation are within the background <br /> range of naturally occurring soils. These concentrations are <br /> also below the Total Threshold Limit Concentration (TTLC) <br /> values of 500 ppm for arsenic and 2,500 ppm for copper. The <br /> TTLC is a concentration established in Title 22 of the <br /> California Administrative Code. These TTLC values are used by <br /> the State Department of Health Services (DHS) to determine <br /> whether a waste is to be classified as hazardous. <br /> The highest concentrations of copper were detected in the soil <br /> samples collected from boring B1 (1.0 to 1. 5 feet below grade; <br /> 660 ppm) and sample #7 (0.75 to 1.25 feet below grade; 380 <br /> ppm) . These concentrations appeared elevated relative to the <br /> other eleven sample results for copper. Therefore, these two <br /> samples were submitted for the WET analysis for copper. The <br /> results of the WET test analyses for thetwosoil <br /> samples, <br /> feet B1 <br /> (1. o to 1. 5 feet below grade) and #7 (0.75 <br /> 07o <br /> ow <br /> grade) , were 17 and 15 ppm, respectively. These <br /> concentrations are below the DHS established Soluble Threshold <br /> Limit Concentration (STLC) of 25 ppm for copper. . <br /> In California, a waste can be hazardous if the WET analysis <br /> results indicate a concentration exceeding the STLC even if <br /> the TTLC is not exceeded. In this case, since both the total <br /> and the WET concentrations were below the TTLC and STLC, <br /> respectively, the soils would not be characterized as <br /> hazardous. <br /> Concentrations of arsenic and copper detected in soil samples <br /> collected for this investigation are not above their <br /> respective TTLCs. In addition, two soil samples (with <br /> elevated levels of copper) submitted for the WET analysis for <br /> copper were below the STLC for copper. Therefore, shallow <br /> soil in the vicinity of the former Ultra Etch storage area <br /> would not be considered a "designated waste. " As a result, <br /> further soils investigation or remediation around the former <br /> Ultra Etch storage area does not appear to be necessary. <br /> 3 <br />