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doses used were 50 mg/L and 100 mg/L Fe(II), which were equivalent to approximately 3 7 times the stoichiometric dose and 7 4 times the stoichiometric dose The amount of �F Cascade° used 0 4 mL Cascade/L GW and 0 8 mL Cascade/L GW These values were determined from preliminary testing of MW-3 GW (no soil) and were equivalent to 2 5 times and 5 times the amount suggested by Eqn 2 Soil (300 g, when applicable), groundwater (1400 mL) and reagents were combined in a glass reactor Clean water was added as needed to bring the total aqueous volume to M 1,500 mL The pH of the Fe(H) tests was adjusted using sulfuric acid, the amount of acid required was based on the data from Section 2 2 The reactors were capped, then placed on a shaker table and gently mixed Controls in which clean water rather than reducing agent was added were also performed The initial conditions of the tests are summarized in Table 2 After about 24 hours, the reactors were destructively sampled the contents were centrifuged, filtered through a 0 45 µm filter, then the aqueous phases was analyzed for all of the parameters listed Table 1, except methane, the formation of which was evaluated separately (see Section 2 4) Soil was not analyzed since the concentration of Cr(VI) was similar to the concentration in background soils Table 2. Initial Conditions for Dose Requirement Test. Test Matrix Fe(II), pH Cascade mL mg/L Cascade°/L GW GW Control GW None None None GWS Control GW+soil None None None GW Low Fe GW 50 2 None GW High Fe GW 100 2 None GWS Low Fe GW+sod 50 -- 2 None GWS High Fe GW+soil 100 2 None GW Low Casc GW None ambient 04 GW High Casc GW None ambient 0 8 LGWS Low Casc GW+sod None ambient 04 GWS High Casc GW+soil None ambient 0 S ' 2.4. Effect of Treatment on Methane To evaluate whether methane could be formed by treatment of soil or GW by Fe(II) or Cascade°, a separate set of tests was performed Each test in Section 2 3 was repeated at 1/10th scale The reactors were amber glass bottles fitted with open top screw-caps and ' septa The reactors were kept upside as much as possible to minimize loss of methane through the septa After 24 hours, the bottles were sent to Air Toxics (Folsom, CA) for analysis of methane in the headspace The volume of headspace in the groundwater only tests was 102 mL, the volume in tests using groundwater and sod was 90 mL PRIMA Environmental 5 Eval of Reductants January 19 2005 ATC-Diamond Walnut r