Mobilization of asbestos fibers by weathering of a corrugated asbestos cement roof

Abstract

Mobilization of asbestos fibers from a 60-year-old corrugated asbestos cement roof was studied in material samples collected from a domestic house in Southern-Norway. Samples included pieces of the roof itself, rainfall simulated run off-water and moss growing on the roof surface. Weathered roof debris below the rain water system was investigated for asbestos fibers leached from the roof, and air samples were collected for asbestos concentrations in ambient air. Micrographs obtained by scanning electron microscopy show that weathering exposed asbestos fibers on the deteriorated roof surface. A high number of fibers found in the run off-water as well as in the weathered roof debris sample illustrates that exposed fibers are prone to mobilization. Investigation of weathering-induced magnesium depletion by scanning electron microscopy energy dispersive X-ray spectroscopy of asbestos fibers collected from the moss, roof underside and surface revealed that fibers had MgO weight % comparable to reference material. The major element chemistry of the fibers is therefore unaltered. Our findings demonstrate that care must be taken when working on and handling old corrugated asbestos cement roof as asbestos fibers might be released. In order to limit exposure to mobile fibers, moss covering asbestos cement roof should not be removed.

Plants, Microorganisms and Their Metabolites in Supporting Asbestos Detoxification—A Biological Perspective in Asbestos Treatment

“…Asbestos fibers get caught up in the moss growing on the covering. Moreover, the presence of mosses accelerates the weathering of the material; on the other hand, mosses deposited on old roof surfaces can prevent the release of fibers, so they should not be removed [165].…”

Asbestos cement materials: impacts on the use and waste generation in Brazil

“…The danger inherent to AC is the large amount of fibers that, when detaching from the composites and being released into the environment, become inhalable. For Ervik et al (2021) the release of fibers in AC roofs occurs mainly due to weathering. Another determining factor for the degradation of AC composites is exposure to acid rain, resulting from the degradation of air quality in urban areas (Fornaro, 2006).…”

Gestão de pequenos volumes de materiais de cimento-amianto no Brasil: do uso aos resíduos

“…mostraram que bactérias nitrificantes como as Nitrosomonas eNitrobacter aumentam a porosidade dos telhados de cimento-amianto e reduzem a resistência devido à produção de ácido nitroso e nítrico.O perigo inerente ao cimento-amianto (CA) é a grande quantidade de fibras que, ao se descolarem dos compósitos e serem liberadas ao meio, tornamse inaláveis. ParaCilia et al (2015) eErvik et al (2021) a liberação das fibras nos telhados de CA deve-se principalmente ao intemperismo. Outro fator determinante à degradação dos compósitos de CA é a exposição à chuva ácida, decorrente da degradação da qualidade do ar em meios urbanos(FORNARO, 2006).…”