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I <br /> EXECUTIVE SUMMARY <br /> Bench-scale treatability testing was conducted on soil (BT- 1 and BT-2) and groundwater <br /> (DPE- 1 S) from the 712 G Street site in Davis, California to evaluate the ability of <br /> hydrogen peroxide (with and without added acid or iron) to destroy gasoline range <br /> organic compounds (GRO) . <br /> Laboratory testing demonstrated that treatment of soil and groundwater with H2O2, acid <br /> and/or chelated or acidified iron could remove GRO from the groundwater. However, <br /> removal was due primarily to volatilization, especially when the initial H2O2 <br /> concentration was as high as 5%. The best degree of GRO destruction was achieved with <br /> acidified H202and with acidified H202 +iron (classical Fenton' s reagent). PRIMA does <br /> not recommend using H2O2/FeEDTA in the field due to the nearly instantaneous and <br /> extremely vigorous reaction. <br /> All treatments generated Cr(VI)—up to 0. 11 mg/L. . The ability of this Cr(VI) to attenuate <br /> naturally was not evaluated in this study. The concentration of Cr(VI) that might be <br /> generated during a field application of a peroxide-based treatment at this site is uncertain <br /> due to differences between laboratory and field conditions. However, the presence of <br /> Cr(VI) at relatively high concentrations in all laboratory tests indicates a high potential <br /> for Cr(VI) formation in the field and any proposed in situ treatment should have a <br /> contingency for Cr(VI) formation. <br /> Treatments employing acid and/or iron increased the concentrations of several metals. <br /> The concentrations of vanadium, magnesium, calcium, chromium, iron, manganese, <br /> cobalt, and nickel increased in tests using acid and acidified iron, while the concentration <br /> of barium decreased. The concentrations of chromium, iron, cobalt, nickel and copper <br /> increased in tests using iron (chelated or acidified), while the concentration of arsenic <br /> decreased to < 0.005 mg/L <br /> The pH did not change by more than one pH unit, even in the tests to which acid was <br /> added. Buffering tests indicate that site soil is highly buffering-100 mmol W (50 mL of <br /> pH 1 solution was neutralized within about 24 hours when combined with 50 g soil . <br /> PRIMA Environmental, Inc. 1 Eval of Peroxide <br /> February 8, 2007 Cambria-'i Street, Davis <br />