Mobilization and redox-cycling of uranium in two boreal sulfidic landscapes: the impacts of Fe-S mineralization pathways and wet-dry cycles

Oxidative weathering of acid sulfate soil and black shale occurs in many places worldwide and releases large quantities of acidity and highly toxic uranium into surrounding environments.

Nowadays, many acid sulfate soils have been drained to increase agricultural production, while groundwater in black shale aquifers has been extracted for irrigation/drinking purposes.

Intensified weather extremes caused by climatic change will further enhance the geographical area, depth penetration, and chemical leaching of these problematic materials.

In turn, this will threaten the drinking water supplies, in particular in densely populated coastal areas where clean water is in high demand.

The proposed project seeks to gain a molecular understanding of biogeochemical cycling of uranium along with the biological critical elements (sulfur and iron) in boreal acid sulfate soil and black shale landscapes.

The integration of experimental and field-based studies using a wide range of biogeochemical and spectroscopic-microscopic tools will yield a wealth of information on the intimate interactions between microorganisms and water/minerals that dictate mobility and redox-cycling of uranium in these two landscapes.

The obtained information can be used to minimize the dispersion of uranium in these two landscapes, by enhancing (i) uranium retention processes within black shale and acid sulfate soils; and (ii) uranium attenuation processes in associated sedimentary environments.