Morphological and chemical properties of fibrous antigorite from lateritic deposit of New Caledonia in view of hazard assessment

Exposure to natural occurrences of asbestos (NOA) and other potentially hazardous elongated mineral particles (EMPs) may pose a risk human health the environment. Weathering forces anthropic activities alter cohesion NOA-bearing outcrops disperse EMPs in air, water, soil. The current paradigm for fibre toxicity indicates that morphology crystal chemistry are key parameters determining toxicological properties mineral. This work aims assess discuss impact sub-tropical supergene alteration weathering on chemical composition antigorite, non-regulated serpentine shares with chrysotile. Antigorite naturally occurring lateritic Ni ores New Caledonia exhibits unique asbestos-like habit at microscopic scale. Standardized mechanical stress was performed antigorites, selected represent different states. specimens produced relevant amount respirable fibres, between 32 42% (WHO counting criteria). PCA data ternary diagrams show all antigorites exhibit similar Si content (from 2.05 2.09 a.f.u.) but were mainly differentiated by Mg content, ranging from 2.66 2.80 0.00 0.09 a.f.u., respectively. Caledonian antigorite is higher than non-lateritic samples. suggests main process occurred after obduction ultramafic protolith. determined enrichment deposits likely cause under environments. Further, processes prompt disaggregation altered causing generation dispersion respirable, hazardous, fibres