Topic 'Naturally Occurring Asbestos, NOA'
Special issue of the Journal of Environmental and Engineering Geoscience (E&EG), Volume 26, Number 1, February 2020
This special issue of the Journal of Environmental and Engineering Geoscience (E&EG) is a summary of the papers presented at a symposium on 'Naturally Occurring Asbestos (NOA)', which was held as part of the XIII Congress of the International Association for Engineering Geology and the Environment (IAEG) and the Annual Meeting of the Association of Environmental and Engineering Geologists (AEG) in San Francisco in September 2018.
Our colleague Dr. Stefan Pierdzig also took part in this symposium on invitation and gave a presentation on the situation in Germany regarding the handling of naturally occurring asbestos.
RESEARCH ARTICLE | FEBRUARY 20, 2020
Regulations Concerning Naturally Occurring Asbestos (NOA) in Germany—Testing Procedures for Asbestos
Environmental and Engineering Geoscience (2020) 26 (1): 67–71.
In Germany, potential asbestos-containing rocks are used as raw materials for a number of engineering applications. These rocks are ultrabasites (dunite, harzburgite), igneous rocks (basalt, gabbro, norite), and metasomatic or metamorphic rocks like talcum, greenschist and amphibolite. Based on the German Gefahrstoffverordung (Hazardous Substances Ordinance), regulatory statutes exist for operations using these rocks and resultant composites and products.
The authorities state that in Germany no natural rocks exist with more than 0.1 mass-% of one of the six regulated asbestos minerals. But it is well known that there are rocks with a high modal concentration of these minerals with a non-asbestiform, columnar to prismatic habitus. Under mechanical stress during handling, they can lead to fibrous cleavage fragments, which conform to the World Health Organization (WHO) “respirable asbestos fiber” definition. In view of this fact, the regulations changed in 2009, with revision of the Technical Rules for Hazardous Substances (TRGS) 517: any fibrous asbestos particles, regardless of whether or not they represent naturally occurring asbestos or are of cleavage origin, are evaluated for potential hazards associated with handling of these rocks.
If the WHO fiber concentration is <0.1 mass-%, rocks and products can be used and re-used under protective measures. At concentrations >0.1 mass-%, the material is considered hazardous waste.
These regulations apply to many industrial sectors that exploit and process rocks, using them in road building and track construction and when they are recycled. Analysis (by scanning electron microscopy, SEM/energy dispersive x-ray spectroscopy, EDS) to determine the asbestos concentration of rocks, gravels, or dusts is carried out in the <100-µm, grain-size fraction produced by sieving or grinding. The results provide a representation of a worst-case examination of the air quality during mechanical treatment of these materials. Workplace monitoring is done by air sampling to survey an exposure limit of 10,000 fibers/m3 of air (0.01 f/cc).