Naturally occurring asbestos in Southern Italy: Geological and mineralogical investigation of fibrous antigorite from Calabrian serpentinites in view of its hazard assessment

In the last few decades, non-occupational asbestos-related diseases have been documented in populations living near naturally occurring asbestos (NOA) sites, including regions in Greece, Cyprus, China, New Caledonia, Turkey, and Italy. This highlights the critical need to assess geological and environmental hazards associated with NOA. Fibrous antigorite, among the >400 naturally occurring fibrous minerals, has emerged as a potential health and environmental hazard. This work examines the morphometrical, mineralogical and surface properties of a fibrous antigorite vein from a serpentinite body at San Mango D'Aquino (Calabria, Italy), relevant to assessing its potential toxicity. The geological site, described through field and petrographic analyses, was selected as representative of serpentinites outcropping over a large area in central Calabria. Results on the morphometric variation induced by a standardized mechanical stress, mineral solubility, and surface chemical reactivity indicated that: i) the fibrous morphology, expressed as % of WHO (World Health Organization) fibres, was largely preserved and consistent with asbestos standards; ii) antigorite fibres have a durability higher than chrysotile and close to a previously characterized fibrous antigorite from Val Varenna, Italy; iii) fibres showed a remarkable redox reactivity, even higher than chrysotile, suggesting that they may promote particle-derived radical imbalance in vitro and in vivo. Our findings revealed that the antigorite fibres from San Mango possess several critical properties commonly associated with asbestos toxicity. On this basis, we identify the NOA site of San Mango as a potential emission source of hazardous antigorite fibres, with significant environmental and public health implications for the surrounding communities.