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Ito
<br /> Tosco Corporation,a subsidiary of Phillips Petroleum Company 5
<br /> Tosco Station#11193,3202 West Hammer Lane,Stockton CA March 7 2002
<br /> vacuum, vapor extraction flow rates, groundwater extraction flow rates, and influent FID
<br /> readings are presented in Table 1
<br /> During the 2-hour DPE event for well VW-1, the applied vacuum was 25 in of Hg, vapor
<br /> extraction flow rates ranged from 13 08 cfm to 15 26 cfm Groundwater elevations for
<br /> wells MW-1R and MW-2R decreased by 0 01 feet, wells MW-8 and MW-5 increased by
<br /> 0 01 feet, and well MW-9 did not show any change in groundwater elevation FID
<br /> readings collected from the vapor extracted ranged from 1,000 ppmv to 15,000 ppmv
<br /> Applied vacuum, vapor extraction flow rates, groundwater extraction flow rates, and
<br /> influent FID readings are presented in Table 1
<br /> During the 92-hour DPE event for wells VW-1, MW-2R, and MW-1R, the applied
<br /> vacuum ranged from 14 in of Hg to 25 in of Hg, and vapor extraction flow rates ranged
<br /> from 13 86 cfm to 42 86 cfm The groundwater extraction flow rates ranged from 0 01
<br /> gpm to 6 2 gpm Groundwater elevations for well MW-5 decreased by 0 01 feet and
<br /> wells MW-4, MW-8, MW-3 and MW-9 increased by 0 02 feet, 0 04 feet, 0 03 feet, and
<br /> 0 03 feet, respectively FID readings collected from the vapor extracted from all wells
<br /> were initially 500 ppmv and decreased to 150 ppmv by the end of the test Applied
<br /> vacuum, vapor extraction flow rates, groundwater extraction flow rates, and influent FID
<br /> readings are presented in Table 1
<br /> LABORATORY ANALYTICAL DATA
<br /> Laboratory analyses of soil vapor samples collected during the DPE tests are summarized
<br /> in Table 2 and shown graphically on Figure 2 As shown on Figure 2, TPHg influent
<br /> concentrations declined from 300 ppmv to 100 ppmv, benzene concentrations declined
<br /> from 5 3 ppmv to 3 7 ppmv, and MtBE influent concentrations declined from 200 ppmv
<br /> to 86 ppmv
<br /> Groundwater samples were collected from wells MW-1R, MW-2R, and VW-1 before and
<br /> after DPE testing Below is a table showing the groundwater concentrations of TPHg,
<br /> benzene, and MtBE in parts per billion (ppb) measured before and after the DPE event
<br /> Refer to Table 3 for a more complete list showing all analyte concentrations The bolded
<br /> values indicate reduced analyte concentrations
<br /> Well# TPHg (lvb) kle"erre(pleb) MtOE(pph)
<br /> Before DPE After DPE Before DPE After DPE Before DPE After DPE
<br /> .VW 1 <100,000 <50,000 <1,000 810 140 000 71,000
<br /> MW IR <100 <50 <1 0 <0 50 220 160
<br /> MW 2R <50,000 <2,000 <500 76 64,000 7,700
<br /> DPE Mass Removal Rates
<br /> The total mass of TPHg, benzene, and MTBE removed during the test were estimated
<br /> using the influent air analytical results, an average well field flow rate, and the time
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