Wie verhalten sich Thallium und Arsen in Bergbaurückständen?

Thallium is a toxic element that is not abundant in the crust of the Earth. When abundant, however, it could enter the environment and inflict severe harm on biota and people. In this work, we have investigated the behaviour of this element at high concentrations, coupled with high amounts of arsenic. The field site in Allchar in North Macedonia is perfect for such work as it is likely the richest accumulation of thallium in the world. We have that thallium is captured by poorly crystalline Tl arsenates, dorallcharite, Tl-bearing pharmacosiderite, and Mn oxides. Ubiquitous Fe oxides bind copious As but very little Tl. This work offers clues as to what happens with Tl at high concentrations and raises questions if this knowledge can be extrapolated to lower concentrations and used for remediation at other sites around the world. More details can be found at https://doi.org/10.1016/j.apgeochem.2021.105114Externer Link.