title: Fractionation of elements by particle size of ashes ejected from Copahue Volcano, Argentina.
abstract: The volcano Copahue, Neuquén province, Argentina has shown infrequent explosive eruptions since the 18th century. Recently, eruptive activity and seismicity were registered in the period July-October, 2000. As a consequence, ash clouds were dispersed by winds and affected Caviahue village located at about 9 km east of the volcano. Samples of deposited particles from this area were collected during this episode for their chemical analysis to determine elements of concern with respect to the health of the local population and its environment. Different techniques were used to evaluate the distribution of elements in four particle size ranges from 36 to 300 microm. X-ray powder diffraction (XRD) was selected to detect major components namely, minerals, silicate glass, fragments of rocks and sulfurs. Major and minor elements (Al, Ca, Cl, Fe, K, Mg, Mn, Na, S, Si and Ti), were detected by energy dispersive X ray analysis (EDAX). Trace element (As, Cd, Cr, Cu, Hg, Ni, Pb, Sb, U, V and Zn) content was quantified by inductively coupled plasma-mass spectrometry (ICP-MS). Nuclear activation analysis (NAA) was employed for the determination of Ce, Co, Cs, Eu, Hf, La, Lu, Rb, Sc, Sm, Ta and Yb. An enrichment was observed in the smallest size fraction of volcanic ashes for four elements (As, Cd, Cu and Sb) of particular interest from the environmental and human health point of view.
authors.affiliation: Comisión Nacional de Energia Atómica, Unidad de Actividad Quimica, Centro Atómica Constituyentes, Av. Gral Paz 1499, B1650KNA-San Martin Pcia. de Buenos Aires, Argentina.
authors.forename: Dario
authors.initials: D
authors.lastname: Gómez
authors.forename: Patricia
authors.initials: P
authors.lastname: Smichowski
authors.forename: Griselda
authors.initials: G
authors.lastname: Polla
authors.forename: Ariel
authors.initials: A
authors.lastname: Ledesma
authors.forename: Sara
authors.initials: S
authors.lastname: Resnizky
authors.forename: Susana
authors.initials: S
authors.lastname: Rosa
mesh_terms: D001118:Argentina; D004784:Environmental Monitoring; D013058:Mass Spectrometry; D019216:Metals, Heavy / Q000032:analysis*; D010316:Particle Size; D011634:Public Health; D018707:Volcanic Eruptions; D014961:X-Ray Diffraction
chemical_list: D019216:Metals, Heavy