ARCHIVED REPORTS_XR0008120 - Laserfiche WebLink

Home Browse Search

' 26 April 2002 AGE-NC Project No 95-0128 Page 6 of 7 ' TPH-g, TPH-d, and BTEX were not detected in the effluent samples Only one effluent sample contained MTBE at 500 µg/1 on 10 December 2001 The analytical results are summarized on Table 4 The laboratory reports for the quarterlymonitonng event(MAI Laboratory ID No 85714, 85715, 88229 to 88231,89491,90160 to 90162,0202258-01 and 02), quality assurance and quality control (QA/QC) reports and the chain-of-custody form are ' included in Appendix C The concentrations of the influent samples over time and the hydrocarbon mass removal calculations are displayed in Appendix D ' 4 4 MASS CALCULATION OF RECOVERED PRODUCT ' The mass of hydrocarbons removed was calculated from the volume of water treated and the concentrations from laboratory analysis A total volume of 471,092 gallons was extracted from between 13 November 2001 and 20 March 2002,based on effluent flow meter observations Based on the total water volume extracted, 1 8 kg or 3 9 lbs of MTBE, 10 kg or 2 3 lbs of benzene, 15 kg or 34 lbs of TPH-g and 2 28 kg or 5 lbs of TPH-d were removed from the site and treated . The removed hydrocarbon mass calculations are displayed in Appendix D 5.0. SUMMARY AND CONCLUSIONS The following conclusions were drawn from the results of investigation this quarter • The highest concentration of dissolved hydrocarbons quantified as TPH-g,TPH-d and BTEX compounds detected in ground water samples occurred In the areas east and northeast of the dispenser islands • The highest concentration of MTBE detected in the ground water samples occurred in monitoring well MW-11,which is situated in the median ofPacific Avenue Lower or non- detectable MTBE concentrations In the down-gradient and cross gradient wells defined the dissolved MTBE plume toward the north and west This may indicate that the dissolved .rTBE Flu'_L_Is detaching from tl;e TPH BTEX hydrocar bore piu1-1v F16',."vs 4 a-1d 5 depicts the dissolved MTBE and TPH-g isocontours • The dissolved MTBE plume has not been defined east of well MW-15 Advanced GeoEnvironmental Inc