Asbestiform Amphiboles in a Marble Quarry: A Case Study from the Province of Córdoba (Argentina)

Abstract

Pure and impure marbles in Argentina have been exploited for hundreds of years for different purposes. Marble processing is varies depending on its use and could include chemical treatments, burning, crushing, milling and polishing. More impure marbles are crushed and used for construction, or discarded in spoil heaps in quarries. There are numerous studies related to the physical and mechanical properties of marbles from the province of Córdoba; however, there are no records about the potential presence of asbestos that could be liberated during processing procedures or degraded by natural agents in spoil heaps. Fibrous samples from a metasomatic zone in an abandoned marble quarry in the Altautina area (Córdoba, Argentina) were studied through polarized light microscopy, X-ray diffraction and electron probe microanalyses. Asbestiform (tremolite) and non-asbestiform amphiboles (tremolite and magnesio-hornblende) were identified as the main phases. Asbestiform amphiboles were concentrated and studied through a stirring degradation test to evaluate morphological and size changes in the fibres by simulating natural water degradation. This process was monitored by stereomicroscopy and scanning electron microscopy. During the test, fibres underwent length (L) and width (W) reduction, maintaining or increasing the initial L/W ratio. Although the action of natural agents can differ from data obtained in laboratory tests, results indicate that the asbestiform fibre size decreases reaching values that can be harmful to human health.