Atmospheric heavy metals in tropical South America during the past 22,000 years recorded in a high altitude ice core from Sajama, Bolivia.

V, Co, Cu, Zn, As, Rb, Sr, Ag, Cd, Ba, Pb, Bi and U have been analysed by inductively coupled plasma sector field mass spectrometry in various sections of a dated snow/ice core drilled at an altitude of 6542 m on the Sajama ice cap in Bolivia. The analysed sections were dated from the Last Glacial Stage ( approximately 22,000 years ago), the Mid-Holocene and the last centuries. The observed variations of crustal enrichment factors (EFc) for the various metals show contrasting situations. For V, Co, Rb, Sr and U, EFc values close to unity are observed for all sections, then showing that these elements are mainly derived from rock and soil dust. For the other metals, clear time trends are observed, with a pronounced increase of EFc values during the 19th and 20th centuries. This increase shows evidence of metal pollution associated with human activity in South America. For Pb an important contribution was from gasoline additives. For metals such as Cu, Zn, Ag and Cd an important contribution was from metal production activities, with a continuous increase of production during the 20th century in countries such as Peru, Chile and Bolivia.

El deslave del 13 de octubre del 2000 del volcán El Altar

El desastre hidrológico del 13 de octubre de 2000, fue provocado, por el colapso parcial de la cara norte del pico Monja grande del volcán El Altar, este deslave de roca cayo en la Laguna Amarilla y generó una gigantesca ola de agua que viajó valle abajo en forma de un flujo de lodo destructivo. Debido al retroceso de los glaciares, similares avalanchas de roca podrían ocurrir de nuevo en El Altar, pero serían poco frecuentes. (AU)