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David Wang <br /> Page 2 <br /> 2) The Draft Phase 1 Report also addresses previous studies <br /> preformed by various contractors and agencies. Twenty three <br /> sites are identified as potential points for the release of <br /> hazardous wastes. The current status of these twenty three <br /> potential sites is not discussed in the Draft Phase 1 Report. <br /> Site status may have an impact on conclusions reached in the <br /> Draft Phase 1 Report and should be included. <br /> i <br /> 3) DHS is very concerned about contamination definition <br /> misuse and the discussions concerning soil contamination in <br /> the unsaturated zone. One term Applied Action Level (AAL) was <br /> improperly used. Specifically: <br /> o page 2-4, section 2. 1. 2 .4 : <br /> This section references recommended California soil <br /> action levels for 1, 1, 1-trichloroethane, 100 milligrams per <br /> kilogram (mg/kg) ; PCE, 2mg/kg; and 1, 2-Dichloroethane 0. 02 <br /> mg/kg. <br /> Soil action levels for any hazardous waste constituents <br /> have not been developed by any California regulatory <br /> agency. The documentation for this statement must be <br /> provided. <br /> The California Total Threshold Limit Concentration (TTLC) was <br /> not adequately discussed. Specifically: <br /> o page 2-3 , section 2. 1. 2 . 2 (point source sampling) <br /> Additional discussion and clarification of results for <br /> the priority pollutant metals scan needs to be provided. <br /> Chromium (Cr) and mercury (Hg) levels, in addition to <br /> that of lead, appear to be above the TTLCs (sample 419A <br /> for Hg and 413A, 415A, 419A, and 422A for Cr) . <br /> o page ES-2 , paragraph 2 : <br /> This paragraph identifies soil concentrations of <br /> tetrachloroethene (PCE) and trichloroethene (TCE) as being <br /> below the TTLCs. TTLCs are used as a criteria for <br /> establishing a substance as a hazardous waste. There is <br /> no further discussion regarding this statement, the <br /> relevance of this statement to DDTCs remediation should <br /> be discussed. <br /> o page 1-19, section 1. 3 . 2 . 1 <br /> This section identifies soil concentrations of PCE and <br /> TCE as being above the TTLC. Again, DHS request the <br /> relevance of this be discussed. <br /> DHS is concerned that cleanup levels for soil will be <br /> implemented based on TTLCs or AALs presented in the Draft <br /> Phase 1 Report. Cleanup levels for soil must represent health <br />