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July 20, 2001 <br /> 2001-0103-01 <br /> Page 4 of 7 <br /> • remove residual groundwater contaminants. During this period it has been estimated that <br /> approximately 13,400 pounds of TPHG have been removed from the site by SVE/AS, <br /> excavation and bioremediation activities collectively(Emcon Report - August 15, 1996) <br /> Reports or Missing Information <br /> No reports or information has been noted as missing from the file (i.e. — UAR's, QMR's, <br /> PAR, FRP etc...) according to PHS/EHD final directive comments stamped and dated <br /> December 1, 2000. <br /> Best Available Technology <br /> Best Available Technology (BAT) applied at the subject site included SVE, air sparging, <br /> contaminated soil excavation and subsequent microbial decomposition with aeration at a <br /> remote location. Natural attenuation also occurred through the entire process. <br /> Excavation, on-site SVE with hydrocarbon thermal destruction, and groundwater air <br /> sparging as described above have removed significant quantities of fuel hydrocarbons. <br /> Excavated soil was transported from the Teichert Stockton site to the Teichert Tracy <br /> facility and stockpiled along the southern edge of the aggregate quarry. Groundwater at <br /> the Tracy facility was estimated at greater then 90 feet bgs and the Tracy location was <br /> approved by PHS/EHD for treatment purposes. Teichert contracted with Bio Converters <br /> of lone, California to perform bioremediation of the stockpiled soil_ The stockpile <br /> measured 220 feet in length, 55 feet in width, and approximately 1.25 feet in thickness. <br /> This volume of soil was calculated to be greater than 550 cubic yards. After completing <br /> and evaluating physiochemical and microbial data from stockpile sampling, Bio <br /> Converters applied a microbial product with follow-up nutrient and moisture maintenance <br /> including hydration and disking in the bermed perimeter and controlled area. Soil <br /> sampling and analyses in October 1999 documents the reduction in hydrocarbon <br /> concentrations in soil following treatment. Concentrations of TPHG and BTEX <br /> compounds were below RDL's for all samples analyzed. TPH as Diesel (TPHD) <br /> concentrations ranging from 4.1 to 16 mg/kg and TPH as motor oil (TPHMO) <br /> concentrations were ranging from 24 to 58 mg/kg were detected in the soil following <br /> treatment. No known baseline data for TPHD and TPHMO concentrations in soil prior to <br /> treatment are available. MTBE was not reported above RDL's in any soil sample <br /> analyzed. (see Stratus Confirmation Soil Boring and Site Closure Report dated November <br /> 1, 1999) <br /> Mass Balance and Residual Estimates <br /> Mass balance calculations of soil containing petroleum hydrocarbons that were <br /> remediated versus hydrocarbons estimated to remain in situ have been completed. The <br /> removal and treatment of petroleum hydrocarbons in soil has previously been estimated <br /> at 13,400 pounds by excavation/treatment and soil vapor extraction/thermal destruction <br /> �. processes (Stratus Conr�m_ation Soil Borin�d Site Closure Report dated November 1, ,r <br /> 1999). The mass of hydrocarbons remaining in soil at the subject site is conservatively <br /> \\Front\project file\Teichert\Stockton-103\Reports\Teichert Stockton Closure Report 0701.doc <br />