Distribution of trace elements in fracture fillings from the “Mina Fe” uranium deposit (Spain) by sequential leaching: implications for the retention processes

Sequential leaching methods have been used to determine the mineralogical distribution of some trace elements for environmental purposes, such as radiological contamination of soils and sediments, bioavailability studies and natural analogues of deep geological radwaste disposals. In this context, a 7-step-sequential leaching protocol is applied to Fe(III)–U(VI)-rich fracture filling materials from the oxidised zone of the “Mina Fe” U deposit to identify and evaluate the main sinks of natural nuclides and other analogue trace elements, since it is crucial in the performance assessment of a nuclear waste repository.