Avaliação e caracterização de fibras de amianto tipo crisotila em telhas de fibrocimento

Abstract

Asbestos is a mineral fiber extracted from hydrated magnesium silicate rocks, widely used, especially in the construction industry, for fiber cement roofing and water tanks. Its main characteristics include thermal, electrical, acoustic, and mechanical resistance, along with high flexibility. Chrysotile asbestos, or white asbestos, is the most common type. Despite its excellent properties, prolonged exposure to fibers can cause serious health damage. The fibers typically enter the body through respiration, overcoming the barriers of the human body and lodging in the lungs, which can lead to pulmonary fibrosis and, eventually, death, characterizing asbestosis. Brazil was one of the largest chrysotile asbestos miners in the world, and a considerable portion of the population still uses products containing these fibers, being exposed to associated diseases. This study evaluated the release of chrysotile fibers from fiber cement tiles in water and deposited particulate material (PM). The transport of fibers occurs through air, water, and interaction with different materials, including PM. The matrices chosen for this study were ultrapure water (UP), lab-prepared rainwater (CS), rainwater (AC), and deposited particulate material (PM). Little literature addresses fibers in water and PM. Tiles from different locations and usage times were collected, and the experimental part was conducted in the laboratory and external environment. The characterization and quantification of fibers were performed using the NIOSH 7402 technique, commonly used for quantifying chrysotile fibers in the air, utilizing Scanning Electron Microscopy coupled with Energy Dispersive Spectroscopy (SEM-EDS) and Infrared Spectroscopy (IR). All experiments were compared with a standard chrysotile sample. Fiber release was observed in the matrices (UP, CS, and AC), but quantification was not possible due to the large number of fibers. For PM samples, there were difficulties in visualizing the fibers. An acid digestion (3050B EPA) was performed to remove the material covering the fibers, but it altered the surface structure of the fibers, as magnesium, one of its constituents, was leached. It concludes that the use of exposed fiber cement tiles can release chrysotile fibers, transporting them to different environmental matrices and posing a risk to the population, given that a large portion of the Brazilian population uses this material.