Alterações recentes nas razões isotópicas de Pb em sedimentos do Canhão Submari...

• Autor(es): Mil-Homens, Mário ; Caetano, M. ; Lebreiro, Susana ; Costa, A. M. ; Richter, T. ; Cesário, R. ; Brito, Pedro ; De Stigter, H. ; Boer, Wim ; Trancoso, Maria Ascensão ; Mouro, F.
• Data: 2009
• Identificador Persistente: http://hdl.handle.net/10400.9/827
• Origem: Repositório do LNEG
• Assunto(s): Contaminação de águas; Sedimentos marinhos; Chumbo; Canhão Submarino de Cascais (Portugal); Margem Continental Portuguesa
• Tipo de Documento: Documento de conferência
• Idioma: Inglês

Descrição

Temporal variations in lead concentrations and stable lead isotopic ratios in two sediment cores from the Cascais Canyon shows changes in sources of Pb during the last two centuries. The increase of total Pb contents wIth the evolution of Pb ratio recorded in both cores reveals the Increase of Pb from industrial sources. Nevertheless, this increase is lower in deeper core location (252-32) due to dilution and mixing with uncontaminated marine materials. An isotopic shift towards lower Pb/Pb in the shallower core (252-35) during the 1970s may reflect the increasing number of vehicles in the Lisboa area during that time.