Combining zinc desorption with EXAFS speciation analysis to understand Zn mobility in mining and smelting affected soils in Minas Gerais, Brazil.

Abstract Zinc contents exceeding regulatory levels have been documented in several areas in Brazil and elsewhere, especially in sites surrounding mining and smelting sites. Studies involving Zn release and speciation are keys to assess the mobility and bioavailability and thus the potential ecological risk of this element. This study evaluated Zn desorption and speciation from soils affected by mining (soils from a mine area, classified as Technosols) and smelting (mine tailing) activities in Brazil with high total Zn contents, ranging from 1.8 to 8.2%, using a stirred-flow approach and synchrotron-based X-ray absorption spectroscopy (XAS), in order to better assess Zn availability and mobility in these environments. The exchangeable fraction, extracted by 0.1 M CaCl2 solution, represented only a small (