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SOIL AND RESIDUE MANAGEMENT PLAN,STOCKTON FORMER MANUFACTURED GAS PLANT SITE <br /> soil exceeded the TCLP and did not pass the fish bioassay test,it will be treated and <br /> disposed of at a RCRA Subtitle C licensed facility. <br /> Therefore,excavated soil from the nine soil areas identified in the RAP will be classified and <br /> managed in one of four ways: <br /> 1. Soil that is below the threshold level for PNAs will be reused onsite as backfill for the <br /> excavation. Some of the soil excavated from Source Areas 1 and 2 and some of the soil <br /> from the six non-source areas is expected to be below the threshold level.A composite <br /> sample from four locations of each 100 cubic yard of stockpiled soil from these areas will <br /> be analyzed for PNAs. <br /> 2. Soil that has PNAs above the threshold level,is not a California or RCRA hazardous <br /> waste,but is a California designated waste will be disposed at a Class II landfill.Based <br /> on the fish bioassay and laboratory results for Source Area 1 and 2 residues,it is <br /> expected that most of the soil from Source Areas 1 and 2 and from the non-source areas <br /> will fit into this category.This soil will be stockpiled in 400 cubic yard stockpiled with a <br /> composite confirmation sample will be collected from each stockpile. <br /> 3. Soil that is California hazardous only,and is not RCRA hazardous was to be treated by <br /> asphalt batching. It was thought that the residues would be in this category and that <br /> asphalt batching would have been used to treat these soils. Based on the results of the <br /> fish bioassay test and the TCLP tests,there is no soil that is expected to be in this <br /> category. If a small amount of this soil is detected,it will be disposed of at a Class I <br /> landfill. <br /> 4. Soil that is RCRA hazardous, that exceeds the Federal toxicity criteria for benzene as <br /> measured by the TCLP will be transported to a RCRA Subtitle C licensed facility. Source <br /> Area 3 (3,070 ft3 or 111 cubic yards) is expected to be in this category based on these <br /> results.A small portion of Source Area 2 will be segregated and stockpiled to determine <br /> if needs to be treated as a RCRA waste. <br /> Therefore,it is expected that asphalt batching will not be used as presented in the RAP. <br /> Sample Collection and Analysis <br /> Two samples each were collected from Source Areas 1, 2 and 3; the source areas are <br /> described in the Final Feasibility Study(FS) (CH2M HILL, 1997) One sample from each <br /> source area was sent to PG&E's Technical and Ecological Services(TES) department in San <br /> Ramon,CA for fish bioassay testing. The Title 22 96-hour Bioassay test was performed <br /> using fathead minnow, the results are attached to this memorandum. <br /> The second set of samples was sent to QAL laboratory in Redding, CA for analysis of the <br /> total concentration of PNAs, BTEX,TPH-gasoline,and TPH-diesel. In addition,the TCLP <br /> analysis for benzene and TTLC analysis for metals(cadmium,chromium,lead,nickel, and <br /> zinc)were conducted. The results of these samples are presented in Table 1. <br /> Source Area 1 <br /> The Source Area 1 sample was collected from a boring that was drilled just north of <br /> monitoring well MW-9.Hand augering was conducted down to 3% feet below ground <br /> surface (bgs)where a very hard layer was encountered.The geoprobe drilling rig was used <br /> SFO/RESIDUE.DOC 2 <br />