ABSTRACT
J.C. Ng EnTox, The University of Queensland, Brisbane, Australia
F. Nogueira INCT-Acqua, Belo Horizonte, Brazil Departamento de Engenharia Metalúrgica e de Materiais, Escola de Engenharia, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
ABSTRACT: Conventional methods for the analysis of arsenic in atmospheric particulate matter provide only bulk concentrations in different particle size fractions. We have developed a method that combines traditional gravimetric and bulk elemental ICP-MS analysis with automated SEM characterization of individual particles. By using this method, it is possible to establish which mineral phases (and non-crystalline matter) and which particle size fractions contribute to the total arsenic content in the atmospheric particulate matter. A less labor-intensive alternative method is currently being trialed using Mineral Liberation Analysis (MLA). Results of the first pilot study carried out in the Paracatu area (Minas Gerais, Brazil), where gold mineralization is associated with arsenopyrite, show that at this specific mine site atmospheric arsenic is primarily associated with organic combustion residues of forest fires, and not with the dispersion of arsenopyrite from the local mine site as previously postulated. This method can be applied in principle to trace the source of any element in atmospheric particulate matter, and can therefore be used to identify and manage activities and sources responsible for the release of potentially toxic elements into the atmosphere.
