Geochemical tracers of northern Portuguese estuarine sediments on the shelf

Araújo, M. Fátima; Jouanneau, Jean-Marie; Valério, Pedro; Barbosa, T; Gouveia, A.; Weber, O.; Oliveira, Anabela; Rodrigues, Armanda; Dias, João Alveirinho

doi:10.1016/s0079-6611(02)00011-3

Cited by 64 publications

(37 citation statements)

References 29 publications

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“…The distribution of heavy metals (Cu, Zn, Cr, Co and Ni) displayed a spatial variation, with high concentrations in the inner-middle shelf and low concentrations in the outer and upper slope sediments. This general decrease is also observed in other areas of the Portuguese continental shelf and indicates that heavy metals of the shelf sediments have been depleted by geochemical processes, during the long residence time of suspended material, by dilution effects and/or by mixing with allochthonous particles such as biogenic carbonate particles (Araujo et al, 2002).…”

Section: Resultados Y Discusiónsupporting

confidence: 68%

“…También se observa este decremento general en otras áreas de la plataforma continental portuguesa, indicando que los metales pesados en los sedimentos de la plataforma han sido reducidos por procesos geoquímicos, durante el largo tiempo de residencia del material suspendido, por efectos de dilución y/o por mezclarse con partículas alóctonas, como partículas biogénicas carbonatadas (Araujo et al, 2002).…”

Section: Resultados Y Discusiónunclassified

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Influence of Aveiro Lagoon heavy metal contents in the adjacent continental shelf (Portugal)

et al. 2005

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A chemical analysis of Al, Ca, Fe, Mg, Cu, Pb, Zn, Cr, Co, Ni and Cd was carried out in 22 surface sediment samples of the continental shelf and upper slope between Espinho and Aveiro (Portugal). To reduce the disturbing effects of grain size, all samples were size-normalized by wet sieving (<63 µm). The fine fraction was digested with concentrated acids and analyzed by flame atomic absorption spectrometry. The Al and heavy metal concentrations displayed a similar distribution pattern, decreasing seaward. Exceptions to this general pattern are Ca, Mg and Pb distributions. The Ca contents are related to carbonated biogenic particles that are very abundant in the outer shelf. Multivariate statistical analysis was applied to all data to assess the behaviour and sources of each element analyzed. The results from factor analysis showed that terrigenous supply (from Aveiro Lagoon flow, coastal erosion and littoral drift), grain size (clay) sorting and anthropogenic influences from Aveiro Lagoon are the major factors controlling spatial variations of chemical elements in the continental shelf between Espinho and Aveiro. Unusually high contents of Pb were found in the middle shelf off Furadouro, but we could not determine the possible source of this contamination.

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Section: Resultados Y Discusiónsupporting

confidence: 68%

Section: Resultados Y Discusiónunclassified

Influence of Aveiro Lagoon heavy metal contents in the adjacent continental shelf (Portugal)

et al. 2005

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“…However, no Cu enrichment was detected on shelf sediments. Furthermore, at the northwestern continental shelf none of the anthropogenic heavy metals enrichment measured within the Douro estuary were detected on the adjacent sedimentary deposits (Araújo et al, 2002). In the present work, Cu and Pb enrichments at the surface layers of the sediment cores are followed by a slight decrease which becomes nearly constant at ~25-30 cm of depth cores.…”

Section: Copper Zinc and Lead Downcore Profilescontrasting

confidence: 56%

“…In other studies along the Portuguese continental shelf adjacent to Tagus and Douro estuaries, rather high Ca concentrations were found at the outer shelf where benthic activities are prominent (Paiva et al, 1997;Araújo et al, 2002), even though Douro river sediment load is depleted in Ca due to the granitic lithology of the northern Portugal (Araújo et al, 2002).…”

Section: Lithogenic/biogenic Elements Downcore Profilesmentioning

confidence: 70%

Copper, zinc and lead impact in SW Iberian shelf sediments: An assessment of recent historical changes in Guadiana river basin

Corredeira¹,

Araújo²,

Jouanneau

2008

Geochem. J.

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In the present study, lithogenic/biogenic and anthropogenic elements were determined in five sediment cores collected at the SW Iberian Continental Shelf in order to investigate the spatial and temporal heavy metal distribution and to associate them with specific continental influences/events.Elemental concentrations suggest a heavy metal (Cu, Zn and Pb) enrichment at the upper sections of all the cores. This enrichment is larger for cores localised closer to the coastline and probably exposed to a stronger continental influence. The geochemical regional background values for the studied elements are reached at ~25-30 cm for all the studied cores with one exception (core 8), which showed to be metal-enriched down to ~80 cm. It is worthnoting that core 8 is located closer to the coastal area, in a different fine sedimentary deposit, in which the deposition rates seem to be considerably higher. Enrichment factors (EF) calculated by using the natural background value determined at the deeper layers show that the EF values vary at the upper sections of cores, between 1.0 and 4.5 and the spatial distribution of the sediment cores show a similar behaviour in the heavy metal distribution patterns along this area of the continental shelf. Cu, Zn and Pb are heavy metals associated with mining exploitation along the Iberian Pyrite Belt, one of the most important mining areas of southwestern Europe, with massive orebodies of these metals. The combination of enrichment factors downcore profiles with sedimentation rate values signifies the beginning of heavy metal pollution in shelf sediments (~200-250 years ago) and is coincident with the mining exploitation reactivation during the XIX century.

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“…The use of geochemical proxies in sedimentological provenance studies has been widely applied in many continental shelf settings, both to reconstruct long timescale palaeoenvironmental history (Zwolsman and van Eck, 1999;Araú jo et al, 2002;Ingram and Lin, 2002;Cundy et al, 2003;Viscosi-Shirley et al, 2003) and to assess anthropogenic impact (Di Lauro et al, 2004). Provenance reconstruction based on geochemical parameters can in fact be applied to various types of sediments and sedimentary rocks, although their application is often not straightforward (McLennan et al, 1993), and must take into account perturbation effects such as grain size (e.g.…”

Section: Introductionmentioning

confidence: 99%

New insights on late Quaternary palaeogeographic setting in the Northern Adriatic Sea (Italy)

Picone

Alvisi

Dinelli

et al. 2008

J Quaternary Science

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Sedimentological, geochemical and micropalaeontological data from sediment cores in the northwestern Adriatic Sea were obtained to reconstruct the stratigraphic framework and palaeogeographic setting during the last post-glacial sea-level rise (14000-6000 yr BP). Four lithostratigraphic units were identified: (a) distal plain deposits (>14000 yr BP), submerged during the first phases of marine ingression; (b) coastal lagoon system; (c) barrier-lagoon system, which is dated back to between 10019 AE 61 and 10228 AE 174 cal. yr BP from 14 C dating on peat and shell remains; (d) marine prodelta deposits (<5500 yr BP). Geochemical data allow the identification of three distinct sediment sources: River Po, River Adige and Eastern Alpine rivers characterised by decreasing Ni/Mg ratios (50-70, 8-15 and 5-10, respectively) and Ba/Al ratios of 45-55, 55-65 and 35-45, respectively. The three sources display different relative abundances in time. During the Lateglacial, the Po is the main sediment source for the southern cores, whereas the Eastern Alps and the River Adige are the main sediment sources for the northern cores. This suggests a northern position of the Po River bed compared to previous studies. Coastal drowning led to a homogenization of the provenance signal within the sediments. Only after the marine transgression does a River Po signal appear in the northern cores. At the same time, in the southern cores the signal of Eastern Alpine rivers becomes stronger. Transgressive barrier-lagoon and recent sediments do not display a predominant signal for provenance indicators.

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Geochemical tracers of northern Portuguese estuarine sediments on the shelf

Cited by 64 publications

References 29 publications

Influence of Aveiro Lagoon heavy metal contents in the adjacent continental shelf (Portugal)

Influence of Aveiro Lagoon heavy metal contents in the adjacent continental shelf (Portugal)

Copper, zinc and lead impact in SW Iberian shelf sediments: An assessment of recent historical changes in Guadiana river basin

New insights on late Quaternary palaeogeographic setting in the Northern Adriatic Sea (Italy)

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