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I. I2.2 Additional Assessment GeoAudit submitted a work plan for the installation of additional soil borings and wells in April 1993. The objective of this phase of investigation was to complete the assessment of the lateral and vertical extent of vadose zone contamination, and to install remedial wells. I One monitoring well, four remediation wells and two additional soil borings were installed during this phase of the investigation. The results of the final investigation at the site were included in the amended FRP submitted by GeoAudit in July of 1993. The locations of all Iwells are illustrated in Figures 2 and 3. In accordance with the FRP, three additional remediation wells were also installed by IGeoAudit in October of 1993. The results of the third quarter monitoring and the data obtained from the installation of remedial wells VW-5, VW-6, and VW-7, were presented in the September 1993 Quarterly Report. 2.3 Quarterly Monitoring Between May of 1990 and June of 1993, several consulting firms, including Sun Tech Environmental, Inc., performed quarterly groundwater monitoring at the site. GeoAudit was retained in July of 1993 to continue quarterly monitoring at the site in accordance with the C & A order. The last quarterly monitoring was performed on December 27, 1993. Monitoring wells MW- 6, MW-7,MW-10, MW-11, MW-12,MW-13, MW-14 and EW-1 were sampled in accordance with C & A order. IPetroleum hydrocarbons were detected in samples from MW-7, MW-10, MW-11, MW-14 and EW-1. The concentrations of petroleum hydrocarbons decreased in MW-14 and EW-1 Ifrom the September 1993 sampling; however, concentrations in MW-7, MW-10 and MW-11 increased. IVolatile halogenated hydrocarbons(HVOC's,EPA 601),specifically 1,2-DCA,were detected in EW-1, MW-13 and MW-14 during the December 1993 sampling. In each well, the concentration of 1,2-DCA increased from the September monitoring. Result of the IDecember monitoring were reported in the Quarterly Report for December 1993 by GeoAudit. I2.4 Blower Installation I In December 1993, a low-pressure blower was installed at the site. The blower was installed to provide a low pressure air source to the remediation wells in preparation for inoculation of the hydrocarbon-consuming bacteria. The blower provides air to remediation wells VW-1 through VW-7 and monitoring wells MW-3, MW-4, MW-5 and MW-14. Initially, the blower was providing air to all the piped wells. However, at the outset of the pilot test (see below), 13-1-AW Audi)� Savior,Inc 3 I.33* LZM QIP