title: Insights of Pb isotopic signature into the historical evolution and sources of Pb contamination in a sediment core of the southwestern Iberian Atlantic shelf.
abstract: Stable Pb isotopic ratios and concentrations of Al, Cu and Pb were measured in a 5m long sediment core (VC2B) retrieved at 96m water depth in the southwestern Iberian Atlantic shelf. Five phases during the last 9.5kyrs were identified, two of them (Roman Period and modern mining) marked by a decrease of206Pb/207Pb ratios reflecting additional inputs of Pb derived from mining activities. The Roman Period was also characterized by high208Pb/206Pb ratios suggesting the exploitation of the outcropping portion of the orebody intensely weathered when compared with the other formations later mined. The shift of208Pb/206Pb ratios towards linearity took approximately 1.0kyrs, which may mirror the time of environmental recovery from the impact of Roman mining activities. The application of a mixing model allowed the quantification of the contribution associated with anthropogenic mining activities to the shelf sediments. The maximum values of Pb contamination occurred in the 20thcentury. This study gives direct evidence of Pb and Cu exploitation over the last 2000years. The stable Pb isotopic signatures point to legacy of mining activities that are still the prevailing metal source recorded in the southwestern Iberian Atlantic shelf sediments.
authors.affiliation: IPMA, Portuguese Institute of Sea and Atmosphere, Rua Alfredo Magalhães Ramalho, 6, 1449-006 Lisboa, Portugal; CIIMAR, Interdisciplinary Centre of Marine and Environmental Research, University of Porto, Rua dos Bragas, 289, 4050-123 Porto, Portugal. Electronic address: mario.milhomens@ipma.pt.
authors.forename: Mário
authors.initials: M
authors.lastname: Mil-Homens
authors.affiliation: CIIMAR, Interdisciplinary Centre of Marine and Environmental Research, University of Porto, Rua dos Bragas, 289, 4050-123 Porto, Portugal.
authors.forename: Carlos
authors.initials: C
authors.lastname: Vale
authors.affiliation: IPMA, Portuguese Institute of Sea and Atmosphere, Rua Alfredo Magalhães Ramalho, 6, 1449-006 Lisboa, Portugal; CIIMAR, Interdisciplinary Centre of Marine and Environmental Research, University of Porto, Rua dos Bragas, 289, 4050-123 Porto, Portugal.
authors.forename: Pedro
authors.initials: P
authors.lastname: Brito
authors.affiliation: IPMA, Portuguese Institute of Sea and Atmosphere, Rua Alfredo Magalhães Ramalho, 6, 1449-006 Lisboa, Portugal; CCMAR, Center of Marine Sciences, Algarve University, Campus de Gambelas, 8005-139 Faro, Portugal.
authors.forename: Filipa
authors.initials: F
authors.lastname: Naughton
authors.affiliation: IPMA, Portuguese Institute of Sea and Atmosphere, Rua Alfredo Magalhães Ramalho, 6, 1449-006 Lisboa, Portugal; IDL, Instituto Dom Luiz, Faculty of Sciences, University of Lisbon, Campo Grande, Edifício C1, Piso 1, 1749-016 Lisboa, Portugal.
authors.forename: Teresa
authors.initials: T
authors.lastname: Drago
authors.affiliation: IPMA, Portuguese Institute of Sea and Atmosphere, Rua Alfredo Magalhães Ramalho, 6, 1449-006 Lisboa, Portugal; CIIMAR, Interdisciplinary Centre of Marine and Environmental Research, University of Porto, Rua dos Bragas, 289, 4050-123 Porto, Portugal.
authors.forename: Joana
authors.initials: J
authors.lastname: Raimundo
authors.affiliation: IPMA, Portuguese Institute of Sea and Atmosphere, Rua Alfredo Magalhães Ramalho, 6, 1449-006 Lisboa, Portugal; Faculty of Sciences, University of the Lisbon, Centre for Molecular Sciences and Materials, Campo Grande, 1749-016 Lisboa, Portugal.
authors.forename: Bárbara
authors.initials: B
authors.lastname: Anes
authors.affiliation: UMR 5805 EPOC OASU, University of Bordeaux, 33615 Pessac, France.
authors.forename: Sabine
authors.initials: S
authors.lastname: Schmidt
authors.affiliation: IPMA, Portuguese Institute of Sea and Atmosphere, Rua Alfredo Magalhães Ramalho, 6, 1449-006 Lisboa, Portugal; CIIMAR, Interdisciplinary Centre of Marine and Environmental Research, University of Porto, Rua dos Bragas, 289, 4050-123 Porto, Portugal.
authors.forename: Miguel
authors.initials: M
authors.lastname: Caetano
keywords: Environment recovery; Marine sediments; Pb isotopes; Roman and modern mining activities; Southwestern Iberian shelf; Temporal evolution