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Mil-Homens, Mário; Stevens, R L; Cato, I (2006): Geochemical analysis of surface sediments along the Portuguese Margin. PANGAEA, https://doi.org/10.1594/PANGAEA.354681, Supplement to: Mil-Homens, Mário; Stevens, R L; Abrantes, Fatima F; Cato, I (2006): Heavy metal assessment for surface sediments from three areas of the Portuguese continental shelf. Continental Shelf Research, 26(10), 1184-1205, https://doi.org/10.1016/j.csr.2006.04.002

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Abstract:
Twenty-nine surface samples from the Portuguese shelf, recovered offshore from the mouths of the Ave, Douro, Lis and Mira rivers, were analysed using ICP–OES for selected major and trace elements, after total dissolution. Organic carbon, carbonate content and grain size were also determined. Five evaluation tools have been applied in order to compare the three study areas and to evaluate sediment geochemistry and other sediment compositional variability in the acquired samples: (1) empirical methods based on comparison with standard reference criteria, e.g. the NOAA sediment quality guidelines, (2) normalisation ratios using a grain-size proxy element, (3) “Gradient Method”, plotting contaminant vs. organic matter or Al, (4) definition of a regional geochemical baseline from a compiled database, and (5) enrichment factors.
The evaluation of element and component associations indicates differences related both to the onshore drainage areas and to the environmental shelf setting. Despite the considerable variability in total metal contents indicated by our results, the sediment metal composition is largely of natural origin. Metal enrichments observed in the Mira area are associated with the drainage of mineralised areas rich in Cu, Pb, Zn, Fe and Mn. The near absence of human impact on shelf sediments, despite the vicinity to urban areas with high industrialisation levels, such as the Ave-Douro and Lis areas, is attributed to effective trapping in the estuaries and coastal zones, as well dilution with less contaminated sediments shelf sediments and removal with fine fractions due to grain-size sorting. The character of the contaminated sediments transported to these shelf areas is further influenced by grain-size sorting as well as by dilution with less contaminated marine sediments. The results obtained individually by the different methods complement each other and allow more specific interpretations.
Coverage:
Median Latitude: 39.476098 * Median Longitude: -9.059265 * South-bound Latitude: 37.638830 * West-bound Longitude: -9.466000 * North-bound Latitude: 41.383330 * East-bound Longitude: -8.861000
Date/Time Start: 2002-04-25T08:15:00 * Date/Time End: 2002-04-30T17:21:00
Minimum Elevation: -145.0 m * Maximum Elevation: -66.0 m
Event(s):
POS287_04-1B * Latitude: 41.383330 * Longitude: -8.961670 * Date/Time: 2002-04-25T08:15:00 * Elevation: -78.0 m * Recovery: 0.2 m * Location: Portuguese Margin * Campaign: POS287 (PALEO 1) * Basis: Poseidon * Method/Device: Box corer (BC) * Comment: Environment
POS287_05-1B * Latitude: 41.374000 * Longitude: -8.998500 * Date/Time: 2002-04-25T09:13:00 * Elevation: -87.0 m * Recovery: 0.49 m * Location: Portuguese Margin * Campaign: POS287 (PALEO 1) * Basis: Poseidon * Method/Device: Box corer (BC) * Comment: Environment
POS287_06-1B * Latitude: 41.335670 * Longitude: -8.987830 * Date/Time: 2002-04-25T10:23:00 * Elevation: -84.0 m * Recovery: 0.25 m * Location: Portuguese Margin * Campaign: POS287 (PALEO 1) * Basis: Poseidon * Method/Device: Box corer (BC) * Comment: Environment
Parameter(s):
#NameShort NameUnitPrincipal InvestigatorMethod/DeviceComment
1Event labelEvent
2Latitude of eventLatitude
3Longitude of eventLongitude
4Elevation of eventElevationm
5AluminiumAl%Mil-Homens, MárioICP-OES, Inductively coupled plasma - optical emission spectrometry
6CalciumCa%Mil-Homens, MárioICP-OES, Inductively coupled plasma - optical emission spectrometry
7IronFe%Mil-Homens, MárioICP-OES, Inductively coupled plasma - optical emission spectrometry
8PotassiumK%Mil-Homens, MárioICP-OES, Inductively coupled plasma - optical emission spectrometry
9MagnesiumMg%Mil-Homens, MárioICP-OES, Inductively coupled plasma - optical emission spectrometry
10ManganeseMn%Mil-Homens, MárioICP-OES, Inductively coupled plasma - optical emission spectrometry
11SodiumNa%Mil-Homens, MárioICP-OES, Inductively coupled plasma - optical emission spectrometry
12PhosphorusP%Mil-Homens, MárioICP-OES, Inductively coupled plasma - optical emission spectrometry
13TitaniumTi%Mil-Homens, MárioICP-OES, Inductively coupled plasma - optical emission spectrometry
14BariumBamg/kgMil-Homens, MárioICP-OES, Inductively coupled plasma - optical emission spectrometry
15CeriumCemg/kgMil-Homens, MárioICP-OES, Inductively coupled plasma - optical emission spectrometry
16ChromiumCrmg/kgMil-Homens, MárioICP-OES, Inductively coupled plasma - optical emission spectrometry
17CobaltComg/kgMil-Homens, MárioICP-OES, Inductively coupled plasma - optical emission spectrometry
18CopperCumg/kgMil-Homens, MárioICP-OES, Inductively coupled plasma - optical emission spectrometry
19LanthanumLamg/kgMil-Homens, MárioICP-OES, Inductively coupled plasma - optical emission spectrometry
20LithiumLimg/kgMil-Homens, MárioICP-OES, Inductively coupled plasma - optical emission spectrometry
21NickelNimg/kgMil-Homens, MárioICP-OES, Inductively coupled plasma - optical emission spectrometry
22LeadPbmg/kgMil-Homens, MárioICP-OES, Inductively coupled plasma - optical emission spectrometry
23RubidiumRbmg/kgMil-Homens, MárioICP-OES, Inductively coupled plasma - optical emission spectrometry
24ScandiumScmg/kgMil-Homens, MárioICP-OES, Inductively coupled plasma - optical emission spectrometry
25StrontiumSrmg/kgMil-Homens, MárioICP-OES, Inductively coupled plasma - optical emission spectrometry
26VanadiumVmg/kgMil-Homens, MárioICP-OES, Inductively coupled plasma - optical emission spectrometry
27ZincZnmg/kgMil-Homens, MárioICP-OES, Inductively coupled plasma - optical emission spectrometry
28Size fraction > 2 mm, gravel>2 mm%Mil-Homens, MárioCoulter counter
29SandSand%Mil-Homens, MárioCoulter counter
30SiltSilt%Mil-Homens, MárioCoulter counter
31Size fraction < 0.002 mm, > 9 phi, clay<2 µm, >9 phi%Mil-Homens, MárioCoulter counter
32Carbon, organic, totalTOC%Mil-Homens, MárioElement analyser CHNS
33Calcium carbonateCaCO3%Mil-Homens, MárioElement analyser CHNS
34Nitrogen, totalTN%Mil-Homens, MárioElement analyser CHNS
Size:
870 data points

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