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15 November 2011 <br />AGE-NC Project No. 99-0670 <br />Page 2 of 4 <br />SVE REBOUND RESPONSE TEST PROCEDURES <br />Following the 22 August 2011 shut off date, SVE operations were suspended at the site <br />for a period of 58 days (2-months). Following the 2-month period, the SVE remediation <br />system was restarted and allowed to operate for a period of 24-hours to achieve <br />equilibrium conditions. After the 24-hour operation period, rebound response SVE influent <br />and effluent air samples were collected utilizing an electric vacuum pump and tedlar bags, <br />labeled, placed in a cooler, and transported under chain of custody to Cal Tech laboratory. <br />Each soil vapor sample was analyzed for total petroleum hydrocarbons quantified as <br />gasoline (TPH-g; EPA method 8015M), benzene, toluene, ethylbenzene and xylenes <br />(BTEX; EPA method 8260B) and methyl tertiary butyl ether (MTBE; EPA method 8260B). <br />The 24-hour rebound response test was concluded after the 20 October 2011 SVE air <br />samples were collected. Following the collection of the 20 October 2011 influent and <br />effluent air samples, all SVE remediation operations were suspended prior to leaving the <br />site. <br />SVE REBOUND RESPONSE TEST FINDINGS <br />Analytical results of the rebound test soil vapor samples collected on 20 October 2011 are <br />as follows: <br />TPH-g were reported in the influent sample at a concentration of 100 pg/I, 2.9 pg/I <br />total xylenes. <br />Target analytes were not detected in the samples collected from the effluent vapor <br />stream. <br />Analytical results are summarized in Table 2. Laboratory reports (CTEL Project Nos. <br />CT214-1110178), laboratory quality assurance/quality control (QA/QC) reports and chain <br />of custody forms are included in Appendix A. Results were uploaded to the State <br />Geotracker database and referenced under confirmation number 1917160987. <br />Utilizing an OVM during the rebound response test (i.e. 19 and 20 October 2011), the <br />concentration of organic vapor was measured from the SVE influent at 79 ppmv (19 <br />October 2011) and 24 ppmv (20 October 2011). Generally, the rebound test influent OVM <br />concentrations were within the normal range of previously encountered OVM <br />concentrations (Table 1). <br />Advanced CeoEnvironmental, Inc.