We present the magnetic, structural and 57Fe Mossbauer characterization of soils collected from an ancient mercury contaminated city named Huancavelica in Peru. The characterization results indicate that silicates and carbonates are the main mineralogical constituents in the samples. In addition, 57Fe Mössbauer spectra at room temperature reveal, the presence of two components: a magnetic component related to magnetic Fe-oxides (magnetite, hematite, goethite) and a high non-magnetic component related to Fe+3 in high spin configuration and tetrahedral coordination in silicates. The magnetization measurements present screening of paramagnetic, ferromagnetic and antiferromagnetic signals, typical from soils containing different silicates and iron minerals. Remarkably the Verwey and Morin transitions corresponding to magnetite and hematite, respectively, are screened by the paramagnetic signal corresponding to the major silicate components in the samples. Overall, the soils are mainly composed of crystalline and amorphous silicates, calcites and iron bearing which are typical from Andean soils.
Bibliographical noteFunding Information:
L. De Los Santos and L. Borja thank the Incorporaci?n de Investigadores Program from the CONCYTEC ? FONDECYT. UNMSM (Contract No. 12 -2019 ? FONDECYT ? BM ? INC. INV.). The authors are indebted to Mr. Ra?l L?pez for his help during collection of the samples, Mr. J. Diaz Solano from the National University of San Marcos for his help during surveying the literature and to Mr. J. Rea Dionicio and Mr. H. Villaverde for the geography information.
© 2021, The Author(s).
- Contaminated soils
- Iron oxides
- Magnetometry of soils
- Mössbauer spectroscopy