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GEOSYNTEC CONSULTANTS L Ms. Amy Terrell 18 November 2004 Page 5 anaerobic bioremediation of chlorinated hydrocarbons (i.e., pesticides) and nitrate detected in groundwater. As reported previously: A new monitoring well,MW-6, was installed on 3 June 2002, approximately 20 feet southwest of MW-2. As shown on Figure 8, MW-6 was located in the approximate center of the grid of Hydrogen Releasing Compound (HRC) ` injection points. Construction details of MW-6 are included in Table 1. • In June 2002, HRC was injected into the uppermost saturated zone at 28 ` locations upgradient of and adjacent to MW-2. The HRC was injected as part of a field-scale pilot test of enhanced in-situ anaerobic degradation of the ` chlorinated hydrocarbons (i.e. pesticides) and nitrate in groundwater at the site. The HRC was applied at a rate of 6lbs/foot over 20 feet (from 22 to 42 feet below ground surface). • Groundwater samples from monitoring wells MW-2, MW-4, MW-5, and MW- 6 are periodically analyzed to gauge the effectiveness of the pilot test. The .. post-injection monitoring results are compared to the results from the pre- injection, "baseline," samples that were collected on 3 and 4 June 2002. Keystone Laboratories of Newton, Iowa, analyzed groundwater samples collected from monitoring wells MW4 (upgradient), MW-6 (intergrid), MW-2 (downgradient), MW-5 (off-site), and for the suite of bioremediation parameters including volatile organic compounds (EPA Method 8260B), permanent gases (ASTM Method D1945), metabolic acids (by HPLC/UV), general chemistry parameters, and total and dissolved metals. Analytical results from Keystone for the 3rd quarter 2004 sampling event are summarized in Table 4. The Keystone analytical laboratory report is provided in Attachment 3. Observations related to monitoring the pilot study are summarized below. • In MW-2, the concentration of 1,2-DCP detected during the 3`d quarter 2004 monitoring event was 16.4 µg/L and, for the second monitoring event in a row since the pilot study began, 1,2,3-TCP was not detected by Keystone above the detection limit of 1.0 µg/L. In the sample analyzed by APPL, 1,2,3-TCP was detected at a concentration of 1.2 µg/L. P:\PRJ2003 RE W W FS\V ER\MON F\3 Q04\W C04066.doc r