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Article

Episodes 2020; 43(3): 851-858

Published online September 1, 2020

https://doi.org/10.18814/epiiugs/2020/0200s01

Copyright © International Union of Geological Sciences.

Environmental asbestos contamination in an abandoned chrysotile mining site: the example of Val Malenco (central Alps, northern Italy)

by Alessandro Cavallo

University of Milano-Bicocca, Department of Earth and Environmental Sciences, Piazza della Scienza 1-4, 20126 Milano (MI) - Italy

Correspondence to:*E-mail: alessandro.cavallo@unimib.it

Received: January 31, 2020; Revised: March 22, 2020; Accepted: March 22, 2020

This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/4.0) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

The Valmalenco area (central Alps, northern Italy) is well-known for the widespread mining and quarrying activities. Serpentinites are extracted and processed as valuable dimension stone in open-cast quarries, and a big underground mine provides talc as industrial mineral. The presence of long-fiber chrysotile veins, especially in the eastern part of the valley, gave rise in the past to widespread mining activity, particularly between the end of the XIX century and 1975, leaving huge amounts of mining waste and tailings. In recent times, part of the tailings have been stabilized and reclaimed, covered with soil and planted. Extensive sampling of mine tailings, soils and alluvial sediments was performed, to detect asbestos contamination (XRPD, SEMEDS, TEM). Airborne asbestos was measured by environmental monitoring on polycarbonate filters (SEM and TEM), at the abandoned mines and at the closest centers. Huge amounts of chrysotile are still present in mine tailings (up to 20 wt.%), whereas soils and sediments were mostly below the 1000 ppm threshold; chrysotile is widespread almost in every part of the valley. Small amounts (< 400 ppm) of asbestiform tremolite were detected. Airborne asbestos was below the PEL of 2ff/l for living environments, with some peaks at mine dumps and close to active serpentine quarries. This preliminary study provides useful tips and effective technical measures for risk reduction in the extractive context.