Table A7.1 Trace ions posing a concern to human health or the environment that can be released during managed aquifer recharge Healtha Environmentb Trace ion Sources Mechanisms Aluminium aesthetic Al(III) pH 9 • • gibbsite in laterites mineral equilibrium • • clay minerals • Antimony sulfides redox 9 – • • Arsenic sulfides redox 9 9 • • Fe(III) oxides pH • • exchange • Barium barite (barium sulfate) mineral equilibrium 9 – • • Fe(III) oxides redox (sulfate • • reduction) carbonates • pH • exchange • Beryllium beryl (silicate) mineral equilibrium – 9 • • Cadmium sulfides redox 9 9 • • Fe(III) oxides pH • • exchange • Chromium sulfides redox 9 9 • • Fe(III) oxides, pH • • chromite in olivine exchange • • inclusions in basalts Cobalt sulfides redox – 9 • • Fe(III) oxides pH • • exchange • Copper sulfides redox 9 9 • • Fe(III) oxides pH • • exchange • Fluoride fluorite mineral equilibrium 9 9 • • apatite in igneous • rocks Iron aesthetic Fe(III) redox 9 • • sulfides pH • • carbonates mineral equilibrium • • Lead sulfides redox 9 9 • • Fe(III) oxides pH • • exchange • Manganese oxides redox – 9 • • carbonates pH • • mineral dissolution •
Table A7.1 Trace ions posing a concern to human health or the environment that can be released during managed aquifer recharge Trace ion Sources Mechanisms Healtha Environmentb Aluminium • Al(III) • pH aesthetic 9 • gibbsite in laterites • mineral equilibrium • clay minerals Antimony • sulfides • redox 9 – Arsenic • sulfides • redox 9 9 • Fe(III) oxides • pH • exchange Barium • barite (barium sulfate) • mineral equilibrium 9 – • Fe(III) oxides • redox (sulfate • carbonates reduction) • pH • exchange Beryllium • beryl (silicate) • mineral equilibrium – 9 Cadmium • sulfides • redox 9 9 • Fe(III) oxides • pH • exchange Chromium • sulfides • redox 9 9 • Fe(III) oxides, • pH • chromite in olivine inclusions in basalts • exchange Cobalt • sulfides • redox – 9 • Fe(III) oxides • pH • exchange Copper • sulfides • redox 9 9 • Fe(III) oxides • pH • exchange Fluoride • fluorite • mineral equilibrium 9 9 • apatite in igneous rocks Iron • Fe(III) • redox aesthetic 9 • sulfides • pH • carbonates • mineral equilibrium Lead • sulfides • redox 9 9 • Fe(III) oxides • pH • exchange Manganese • oxides • redox – 9 • carbonates • pH • mineral dissolution
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