Laserfiche WebLink
1 S E C 0 R <br /> • <br /> ' 5 0 PETROLEUM HYDROCARBON DISTRIBUTION AND CONCENTRAITON <br /> TRENDS w <br /> 51 Distribution of Petroleum Hydrocarbons Soil <br /> 5 1 1 Distribution of Hydrocarbons in Soil <br /> ' Concentrations of TPHg, benzene, MtBE, and 1,2-DCA and the approximate extent of adsorbed <br /> hydrocarbons in soil are illustrated on Figure 4 Maximum adsorbed concentrations are located <br /> in the vicinity of the pump islands and beneath the southern portion of the UST pit The ti <br /> maximum adsorbed concentrations were detected beneath the dispensers at approximately 60 <br /> feet bgs (4,780 mglkg TPHg in MW-6 at 60 feet bgs) <br /> 51 1 1 Distribution of Hydrocarbons in Shallow Soil <br /> , <br /> The distribution of hydrocarbons in shallow sod has been delineated by wells MW-1 through <br /> MW-4 No detectable concentrations of TPHg, benzene, MtBE, or 1,2-DCA were reported in soil 7N, <br /> samples analyzed to a depth of 45 feet bgs <br /> 51 12 Distribution of Hydrocarbons in Intermediate Soil <br /> During the vertical assessment conducted in July 2000 (GP-1 through GP-3) and the installation <br /> of on-site, B monitoring zone wells MW-5 through MW-10 between November 2000 and ) <br /> September 2001, hydrocarbon impacts to soil at depths ranging from 60 to 80 feet bgs were ; <br /> reported Maximum concentrations of TPHg and benzene were reported at a depth of 60 feet 4 <br /> ' bgs to wells MW-5 through MW-10 Four additional B monitoring zone wells (MW-11 through 'fi <br /> MW-14) were installed in June and July 2003 to delineate intermediate-depth soil impacts No ,E <br /> detectable concentrations of TPHg, benzene, MtBE, or 1,2-DCA were reported in soil samples <br /> ' from MW-11 through MW-14 with the exception of 1,2-DCA (0 0071 mg/kg) in well MW-12 at 70 <br /> feet However, the detection of 1,2-DCA to MW-12 at 70 is cross-to-up gradient from the <br /> Former 76 Station The installation of wells MW-11 through MW-14 completed delineation of <br /> ' hydrocarbon impacted soil in the B monitoring zone <br /> k � <br /> 51 13 Distribution of Hydrocarbons in Deep Soil 't <br /> ' The distribution of hydrocarbons in deep soil has been delineated by the boring for MW-17 and <br /> soil borings SB-1D and SB-2D, which were sampled to 2004 (SECOR, August 13, 2004) Soil <br /> samples from MW-15 and MW-16 were not collected since adequate data has been collected <br /> ' from assessments done in the immediate vicinity of those two wells No detectable <br /> concentrations of TPHg, benzene, MtBE, or 1,2-DCA were reported in soil samples to a depth of <br /> 120 feet bgs Total xylenes were detected at a concentration of 0 017 mg/kg in the sod sample <br /> ' collected at 120 feet bgs from the boring for MW-17 Historical soil data is included in Table 2, <br /> and a summary of the soil analytical data from the current assessment (MW-17) is included in p <br /> Table 5 <br /> 1 52 Petroleum Hydrocarbons to Groundwater <br /> Concentrations of TPHg, benzene, MtBE, and 1,2-DCA in groundwater in the A, B, and C � <br /> monitoring zones from April 2005 are illustrated on Figures 8 through 19 <br /> , t <br /> d <br /> 1 <br /> Updated SCM 2005 doc <br /> 77CP 64409 05 0005 <br /> n <br />