Characterizing As, Cu, Fe and U solubilization by natural waters

The effects of carbonate concentration and the presence of in-situ generated iron oxide and hydroxide phases (iron oxyhydroxides) on arsenic (As), copper (Cu), and uranium (U) release from natural rocks were investigated under oxic conditions and in the pH range from 6 to 9. For this purpose non-disturbed batch experiments were conducted with a constant amount of each contaminant bearing rock/mineral and different types of water (deionised, mineral, spring, and tap water). For comparison parallel experiments were conducted with 0.1 M Na2CO3 and 0.1 M H2SO4. The favourable role of carbonate bearing minerals for U and Cu transport could not be confirmed by using dolomite. The presence of elemental iron and pyrite retards As, Cu and U solubilization. This study shows that using natural materials in laboratory investigations is a practical tool to investigate natural processes