Laserfiche WebLink
27 July 1998 <br /> AGE-NC Protect No 95-0130 <br />' Page 4 of 5 <br /> observed from wells V W-I C and VW-2 A(Table 2) The substantial increases reported from <br />' VW-I C and VW-2A could be attributed to the recent increase of ground water elevation <br /> • From September 1997 to June 1998, a substantial decrease in dissolved hydrocarbon- <br /> concentrations were observed from well MW-5 (Table 2) A plot of depth to ground water <br /> and TPH-g concentrations over time (Appendix C) suggests a positive correlation at well <br /> MW-5 between increasing/decreasing depth to ground water and increasing/decreasing <br />' petroleum hydrocarbon concentrations <br /> • TBA continues to be detected in water samples collected from MW-3 <br />' • Concentrations of benzene detected in samples collected from wells MW-2, MW-3, MW-5, <br /> VW-I C, VW-2A and VW-3A were above the State of California Maximum Contaminant <br />' Level (MCL) for drinking water of 1 0 ppb <br /> • Concentrations of toluene were above the MCL of 150 ppb in wells VW-1C, VW-2A and <br /> VW-3A <br />' • Concentrations of ethylbenzene were above its MCL of 700 ppb in wells VW-I C, VW-2A <br /> and VW-3A <br /> • Concentrations of xylenes were above the MCL of 1,750 ppb in wells VW-I C, VW-2A and <br /> VW-3A <br />' • Utilizing EPA Methods 8020 and 8260, detectable concentrations of MTBE were measured <br /> in samples from wells MW-3, VW-2A and VW-3A <br />' • DIPE, TAME and ETBE were not detected utilizing EPA Method 8260 in the laboratory <br /> analysis of any ground water samples <br /> • The elevated concentrations of petroleum hydrocarbons detected in samples collected from <br />' wells VW-I C, VW-2A and VW-3A indicate that these wells are within or near the dissolved <br /> petroleum hydrocarbon "core area" of the plume <br /> 5.0. RECOMMENDATIONS <br /> Based on the results of this andrevio <br /> p us monitoring events, and on AGE's familiarity with the site, <br /> we recommend <br /> • InstalIation of the remediation system upon regulatory approval of the Remedial Action Work <br /> Plan, dated 03 July 1997, submitted to the PHS-EHD for an to-situ soil vapor extraction/air <br /> sparging system within the petroleum hydrocarbon "core area" <br /> Advanced GcoEnvtronmental,Inc <br />