Characteristics of natural asbestos minerals and associated health risks in the Karaman region (Türkiye)

Abstract Despite extensive research on asbestos mineralogy and health impacts, comprehensive multi-analytical characterization of naturally occurring asbestos (NOA) in ophiolitic mélanges of central Türkiye is still lacking. The present study examines asbestos-form minerals within the ophiolitic mélange northeast of Kıraman village (Karaman, Türkiye), with a focus on chrysotile, tremolite, and talc. These minerals were formed through intensive alteration processes, including serpentinization, talc formation, listwanitization, chloritization, carbonation, and silicification. The main objective was to characterize the mineralogical, morphological, and chemical features of asbestos-form serpentine and amphibole minerals and to evaluate their potential environmental and health implications. Analytical techniques such as optical microscopy, X-ray diffraction (XRD), differential thermal analysis–thermogravimetry (DTA–TG), Fourier-transform infrared (FTIR) and Raman spectroscopy, as well as scanning and transmission electron microscopy with energy-dispersive X-ray spectroscopy (SEM–EDX, TEM–EDX), were employed. The results confirmed the presence of nearly pure chrysotile, talc, and tremolite. Thermal and vibrational analyses revealed characteristic dehydroxylation reactions and diagnostic spectral bands. The SEM and TEM imaging displayed fibrous and acicular morphologies, while TEM–EDX confirmed typical chemical compositions, including minor Fe content (3–5%). Both chrysotile and tremolite fibers exhibited dimensions within the respirable range and elemental characteristics that are commonly associated with increased toxicity in asbestos minerals. The co-existence of Fe-bearing chrysotile and respirable-size tremolite fibers indicates a potential for asbestos-related health risks under conditions of environmental disturbance or exposure. These findings underscore the need for environmental monitoring and suggest the regional geological formations are a potential public health concern.