in the Environment

5.1 The Presence of Chromium in the Environment 1635.1.1 Antropogenic Sources 1645.1.2 Natural Sources 1655.2 Geochemistry of Chromium 1655.2.1 Cr(III) 1665.2.2 Cr(VI) 1675.3 Oxidation-Reduction of Chromium 1685.3.1 Review of Oxidation-Reduction Reactions 1685.3.2 General Redox Behavior of Chromiumin the Environment 1695.3.3 Oxidation of Chromium 1705.3.3.1 Oxidation of Cr(III) to Cr(VI) by Dissolved Oxygen and Manganese Dioxides 1715.3.3.2 Oxidation of Cr(III) to Cr(VI) by H