title: Major factors influencing the elemental composition of surface estuarine sediments: the case of 15 estuaries in Portugal.
abstract: Upper sediments (0-5 cm) were sampled in 94 sites of water bodies of the fifteen Portuguese estuaries characterized by distinct settings of climate, topography and lithology, and marked by diverse anthropogenic pressures. Confined areas recognized as highly anthropogenic impacted, as well as areas dominated by erosion or frequently dredged were not sampled. Grain size, organic carbon (Corg), Al and trace elements (As, Cd, Co, Cr, Cu, Hg, Ni, Pb and Zn) were determined. Normalisation of trace element concentrations to Al and Corg, correlations between elements and Principal Component Analysis (PCA) allowed identifying elemental associations and the relevance of grain-size, lithology and anthropogenic inputs on sediment chemical composition. Whereas grain-size is the dominant effect for the majority of the studied estuaries, the southern estuaries Mira, Arade and Guadiana are dominated by specific lithologies of their river basins, and anthropogenic effects are identified in Ave, Leça, Tagus and Sado. This study emphasizes how baseline values of trace elements in sediments may vary within and among estuarine systems.
authors.affiliation: IPMA, Portuguese Institute of Sea and Atmosphere, Division of Environmental Oceanography and Bioprospection, Av. Brasília, 1449-006 Lisboa, Portugal; CIIMAR, Marine and Environmental Research Center, Rua dos Bragas, 289, 4050-123 Porto, Portugal. Electronic address: mario.milhomens@ipma.pt.
authors.forename: M
authors.initials: M
authors.lastname: Mil-Homens
authors.affiliation: IPMA, Portuguese Institute of Sea and Atmosphere, Division of Environmental Oceanography and Bioprospection, Av. Brasília, 1449-006 Lisboa, Portugal; CIIMAR, Marine and Environmental Research Center, Rua dos Bragas, 289, 4050-123 Porto, Portugal.
authors.forename: C
authors.initials: C
authors.lastname: Vale
authors.affiliation: IPMA, Portuguese Institute of Sea and Atmosphere, Division of Environmental Oceanography and Bioprospection, Av. Brasília, 1449-006 Lisboa, Portugal; CIIMAR, Marine and Environmental Research Center, Rua dos Bragas, 289, 4050-123 Porto, Portugal.
authors.forename: J
authors.initials: J
authors.lastname: Raimundo
authors.affiliation: IPMA, Portuguese Institute of Sea and Atmosphere, Division of Environmental Oceanography and Bioprospection, Av. Brasília, 1449-006 Lisboa, Portugal.
authors.forename: P
authors.initials: P
authors.lastname: Pereira
authors.affiliation: IPMA, Portuguese Institute of Sea and Atmosphere, Division of Environmental Oceanography and Bioprospection, Av. Brasília, 1449-006 Lisboa, Portugal.
authors.forename: P
authors.initials: P
authors.lastname: Brito
authors.affiliation: IPMA, Portuguese Institute of Sea and Atmosphere, Division of Environmental Oceanography and Bioprospection, Av. Brasília, 1449-006 Lisboa, Portugal; CIIMAR, Marine and Environmental Research Center, Rua dos Bragas, 289, 4050-123 Porto, Portugal.
authors.forename: M
authors.initials: M
authors.lastname: Caetano
mesh_terms: D000818:Animals; D004784:Environmental Monitoring; D063366:Estuaries; D019015:Geologic Sediments / Q000737:chemistry*; D019216:Metals, Heavy / Q000737:chemistry*; D011174:Portugal; D025341:Principal Component Analysis; D045483:Rivers / Q000737:chemistry; D014131:Trace Elements / Q000032:analysis
chemical_list: D019216:Metals, Heavy; D014131:Trace Elements
keywords: Anthropogenic pressure; Lithological influence; Portuguese estuaries; Sediments; Trace elements