Characterization of natural 210Po-rich fibrous epsomite and possible risks to human health

The toxicity of fibrous minerals is usually evaluated only in the case of biopersistent minerals because they can remain in the lungs or in other biologic environments for a long time causing several illnesses. Very scarce knowledge exists, at the date, on the accurate chemical composition and the effect of particulates and fibres with high solubility (in water and biological environments). To reduce this lack, natural fibrous epsomite from Perticara Mine (Central Italy) was investigated through SEM-EDS, XRPD, ICP-AES and alpha spectrometry measurements. The morphological and morphometrical investigations on the epsomite sample highlight the presence of a significant number of small fibres potentially inhalable for humans, with an equivalent aerodynamic diameter (D_ae) value of 5.09 μm. Moreover, toxic elements (As, Co, Fe, Mn, Ni, Sr, Ti, Zn) and radioactive isotopes (²¹⁰Po and ²²⁸Th) were detected in the epsomite fibres by chemical analysis. In particular, a surprisingly high amount of of ²¹⁰Po (5.59 Bq/g) was detected in the investigated epsomite sample. The first results of this study were recently published by Giordani et al. (2022). Due to the high solubility of epsomite at lung conditions (37 °C and 100% relative humidity; Chipera and Vaniman, 2007), the inhaled fibres rapidly became a solution and can be potentially adsorbed from all parts of the respiratory tract. Consequently, the entire cargo of hazardous elements could be quickly released into the lung environment and thus affect human health. Natural epsomite is a widespread mineral (e.g., in mines, geological outcrops, mineral springs, efflorescence) and has several applications (Ruiz-Agudo et al., 2008).

Our findings suggest great caution in handling epsomite samples, and our work can be considered a representative case study to investigate the interaction between soluble minerals and human health. These preliminary results can be the basis for further studies on the content of hazardous elements in building materials and regarding toxic elements interaction with humans.

 

Giordani, M., Meli, M. A., Roselli, C., Betti, M., Peruzzi, F., Taussi, M., Valentini, L., Fagiolino, I. and Mattioli, M. 2022. Could soluble minerals be hazardous to human health? Evidence from fibrous epsomite. Environmental Research, 206, 112579. https://doi.org/10.1016/j.envres.2021.112579

Chipera, S.J., Vaniman, D.T., 2007. Experimental stability of magnesium sulfate hydrates that may be present on Mars. Geochimica et Cosmochimica Acta 71, 1, 241-250. https://doi.org/10.1016/j.gca.2006.07.044.

Ruiz-Agudo, E., Putnis, C.V., Rodriguez-Navarro, C., 2008. Interaction between epsomite crystals and organic additives. Crystal Growth and Design, 8(8), 2665-2673. https://doi.org/10.1021/c