Transformations of lead minerals in carbonate rich solutions and their implications on lead bioaccessible fractions in calcareous soils

The stability of lead phases in mine tailings is often disturbed by acidic streams produced during iron sulfide weathering. Although, in gypsum-and/or calcite-rich deposits acidity is buffered, lead mobility is thought to be small during galena oxidation due to the formation of anglesite-like phases. However, both the dispersion of lead and an increase of its bioaccessibility have been observed for this kind of deposits and the soils formed on them due to progressive transformation of secondary phases such as cerussite. Hence, we evaluated the anglesite-cerussite transformations by electrochemical methods in order to describe the evolution of galena under semi-alkaline high carbonated conditions associated with calcareous materials or soils.