HR: 0830h
AN: V51D-0314    [PDF]
TI: Respiratory Health Effects of Volcanic Ash - a new Approach
AU: * Horwell, C J
EM: claire.horwell@bris.ac.uk
AF: Department of Earth Sciences, University of Bristol, Wills Memorial Building, Queens Road, Bristol, BS8 1RJ United Kingdom
AU: Fenoglio, I
AF: Dipartimento di Chimica IFM, Universita degli Studi di Torino, Via P. Giuria 7, Torino, 10125 Italy
AU: Sparks, R J
AF: Department of Earth Sciences, University of Bristol, Wills Memorial Building, Queens Road, Bristol, BS8 1RJ United Kingdom
AU: Ragnarsdottir, K V
AF: Department of Earth Sciences, University of Bristol, Wills Memorial Building, Queens Road, Bristol, BS8 1RJ United Kingdom
AU: Fubini, B
AF: Dipartimento di Chimica IFM, Universita degli Studi di Torino, Via P. Giuria 7, Torino, 10125 Italy
AB: Attempts to characterise the toxicity of volcanic ash have focused on the presence of the crystalline silica polymorph cristobalite, which is known to cause silicosis and lung cancer in industrial settings. Within the lung, it is the surface of the particles which will react with endogenous molecules. Free radicals, produced on particle surfaces, can react with DNA and other cellular components, instigating a chain of toxic events. For the first time, the ability of volcanic ash to form free radicals has been assessed using Electron Paramagnetic Resonance techniques specific to the hydroxyl radical. Respirable ($<$ 4 microns) crystalline silica, separated from volcanic ash from the Soufriere Hills volcano, Montserrat, West Indies, did not produce hydroxyl free radicals or surface radicals. However, the ash, itself, generated up to 3 times more hydroxyl radicals than a quartz of known toxicity. The cause of the reactivity is reduced iron on the surface of iron-rich minerals such as amphiboles and pyroxenes. Fresh volcanic ash generates more free radicals than weathered volcanic ash which will have oxidised (and leached away) surface iron. These results have implications for volcanic health hazard research as it was previously assumed that volcanoes which did not produce respirable crystalline silica presented a lesser respiratory health hazard. The International Volcanic Health Hazard Network (IVHHN) promotes research into the health effects of volcanic emissions. Under the auspices of IVHHN, volcanic ash samples from volcanoes world-wide are being analysed for surface reactivity, grain-size distribution and composition to form a comprehensive database for use by volcano observatories, emergency managers, medical practitioners and researchers. The results will highlight volcanoes which have the potential to cause a respiratory health hazard through generation of iron-catalysed free radicals, as well as more conventional markers such as concentration of respirable particles. At the onset of new eruptions, the database will be used to aid the rapid assessment of health hazard from volcanic ash.
UR: http://eis.bris.ac.uk/~glcjh/ivhhn
DE: 0345 Pollution--urban and regional (0305)
DE: 0370 Volcanic effects (8409)
DE: 0400 Biogeosciences
DE: 8400 VOLCANOLOGY
DE: 8404 Ash deposits
SC: Volcanology, Geochemistry, Petrology [V]
MN: 2003 Fall Meeting