Sediment and pollutant transport in the Northern Gulf of Cadiz: A multi-proxy approach

Montero

Int. J. Environ. Sci. Technol.

et al. 2014

The spatial distribution and geoaccumulation indices of four heavy metals were investigated in very shallow marine sediments of southwestern Spain. Surface sediments were collected from 43 sites with water depth ranging from 3 to 20 m. High to very high pollution levels (I geo [ 4 for zinc, lead and copper) were detected near the end of the Huelva bank, whereas chromium shows a more hazardous distribution in the southwestern Spanish littoral. Low to moderate heavy metal contents (mainly zinc and lead) were also observed in other two areas at different water depths (Isla Cristina-Piedras River: 10-18 m water depth; Mazagón-Matalascañas: \10 m water depth), whereas unpolluted to moderately polluted sediments were detected in the very shallow zones (\8 m water depth) located between the mouths of the Guadiana and the Piedras Rivers. A regional scenario indicates a strong pollution of the adjacent marine areas by polluted inputs derived from the TintoOdiel rivers, with a partial transport of heavy metals by W-E littoral currents even 40 km eastward. The Guadiana River is an additional source of zinc-lead contamination near the Spanish-Portuguese border, mainly at water depths up to 10 m. All these rivers are affected by acid mine drainage processes, derived from millennial mining activities. This pollution affects the sediment quality even 40 km eastward.

Section: Cluster Analysissupporting

confidence: 86%

Distribution of heavy metals and pollution pathways in a shallow marine shelf: assessment for a future management

Montero

Int. J. Environ. Sci. Technol.

et al. 2014

“…Maximum concentrations exist in the mouth of the Odiel-Tinto rivers. Although river �ows are much smaller than those of the Guadiana and Guadalquivir, the Odiel-Tinto rivers are considerably more contaminated [40] and, indeed, they have been recognized as the main source of metals along the coast [102]. A map of computed dissolved Zn concentrations at the surface for summer 1997 is presented in Figure 24 together with a contour plot obtained from empirical data [104], which shows essentially the same banded structure.…”

Section: Metal Transportmentioning

confidence: 89%

“…As widely discussed [40], there is a dominant eastward transport throughout the entire northern GoC. Some authors [99] have postulated the existence of some westward transport of sediments released by the Guadalquivir River in the inner shelf, although little indication of it has been found in other works [40].…”

Section: Suspended Particle Transportmentioning

confidence: 92%

See 1 more Smart Citation

Water Circulation, Sediment Transport, and Pollutant Dynamics in Southern Iberia Waters: A Review on Numerical Modelling Studies

Periáñez

2013

ISRN Oceanography

Southern Iberian Peninsula coastal waters have a high ecologic and economic value. e objective of this work has consisted of describing numerical models which simulate the dispersion of particle-reactive tracers in these waters and reproducing measured concentration levels in water and bed sediment samples. Additionally, information on suspended matter concentration distributions and sedimentation rates is obtained. In the Alboran Sea, the model has been applied to simulate the transport of radionuclides introduced from atmospheric fallout. Transport pathways of heavy metals discharged from three rivers draining a large mining area have been obtained for the Gulf of Cadiz. It has been found that these rivers constitute a source of trace elements to the Mediterranean through the Strait of Gibraltar. Some characteristic times have been calculated, as well as �uxes of isotopes through the Strait of Gibraltar, as additional results of environmental interest.

“…Recently, studies have been published evaluating the consequences of changes that occurred in some main rivers' sediment loading during the last centuries in SW Iberia and the adjacent continental shelf (Gonzalez et al, 2007;Machado et al, 2005;Morillo et al, 2004). However, geochemical studies have focused mainly on surface sediments rather than assessing historical trends.…”

Section: Introductionmentioning

confidence: 99%

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.

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.