Two opposite cases of metal accumulation in ria sediments: Ferrol and Corme-Laxe (Galicia, NW Iberian Peninsula)

Abstract

Ciencias Marinas (2005) AbstractThe accumulation of heavy metals (Cd, Cu, Pb and Zn) in surface sediments (<63 µm) of the Ferrol and Corme-Laxe rias was studied. These two rias have opposite characteristics from the point of view of both the morphology and the anthropogenic impact. Low metal concentrations were found in the Corme-Laxe Ria, with the highest values observed in the Anllóns River estuary, probably due to a higher lithogenic composition of the sediments. Concentrations in the Corme-Laxe Ria (Cd, 0.10 ± 0.03 µg g -l ; Cu, 5 ± 2 µg g -l ; Pb, 12 ± 4 µg g -l ; and Zn, 49 ± 17 µg g -l ) can be used as a good reference for metal background values for sediments from the 18 Galician rias. Although these background values are lower than those previously reported for the Galician coast, they are similar to those found in other uncontaminated coastal and marine systems. The highest concentrations for Ferrol were generally found in the middle part of the ria, which receives the most important urban and industrial impact. The values obtained show evident metal contamination in the middle and inner parts of the Ferrol Ria, with enrichment factors of 4-10 for Cd, 5 for Cu, 2-3 for Pb and 4-5 for Zn.Key words: heavy metals, contamination, sediments, background values, Ferrol, Corme-Laxe, Galicia. ResumenSe estudió la acumulación de metales pesados (Cd, Cu, Pb y Zn) en el sedimento (<63 µm) superficial en las rías de Ferrol y Corme-Laxe, las cuales poseen características contrapuestas tanto desde el punto de vista de su morfología como de su influencia urbana e industrial. La ría de Corme-Laxe presentó bajos niveles de metales en los sedimentos, siendo mayores en el estuario del Río Anllóns probablemente debido a un mayor grado litogénico de los sedimentos. Las concentraciones obtenidas en la ría de Laxe (0.10 ± 0.03 µg g -l de Cd, 5 ± 2 µg g -l de Cu, 12 ± 4 µg g -l de Pb y 49 ± 17 µg g -l de Zn) resultan una buena referencia de valores naturales de fondo para metales en las 18 rías gallegas. Aunque éstos son menores a otros considerados para la costa gallega, son similares a los medidos a nivel mundial en sedimentos marinos no contaminados. En Ferrol, las máximas concentraciones de metales se presentan generalmente en la parte media de la ría, donde se localiza el mayor núcleo de población y buena parte de la actividad industrial. Los datos allí obtenidos señalan la existencia de una evidente contaminación metálica en la parte media e interna de la ría de Ferrol con factores de enriquecimiento comprendidos entre 4-10 para Cd, 5 para Cu, 2-3 para Pb y 4-5 para Zn.

Background Values, Distribution and Contamination of Metals in the Sediments of the Pontevedra Ria (NW Spain)

“…In the estuary, their NEFs were slightly higher, probably resulting from some contamination in the area or just a difference in the lithogenic composition of the riverine sediments, which are naturally richer in metals as has been reported for other Galician Rias (e.g. Cobelo-Garcia et al, 2005). For Pb, the average NEFs are indicative of a null/low contamination both in the ria and estuary.…”

A weight of evidence approach for quality assessment of sediments impacted by an oil spill: The role of a set of biomarkers as a line of evidence

“…Previous studies in Bay of Corme-Laxe detected severe contamination of the sediments by Cu (Prego et al, 2006), however a fuel oil origin was unlikely, with the major source of Cu being antifouling paints from the hulls of fishing vessels (Cobelo-García and Prego, 2003). Although contamination by Cu and Zn was observed in the uppermost sediment layers of the Prestige shipwreck area (Prego and Cobelo-García, 2004;Cobelo-García et al, 2005), this contamination is unlikely not be related to the shipwreck, because levels of Cu in the fuel oil carried by the Prestige were relatively low (3.39 mg kg À1 ) and previous studies have shown that inputs from terrestrial sources are probably higher than from the spilled fuel oil (Carballeira et al, 1997;Villares et al, 2007). Some of the studied variables demonstrate the stress of these contaminants and the effects on the benthic community; however, the results mostly point to chronic contamination with low bioavailability, and potential, but unconfirmed biological risk.…”

Evaluation of the toxicity of an oil spill conducted through bioassays using the fish Solea senegalensis

“…Anthracene, fluoranthene, and pyrene showed acute toxicity in marine invertebrate embryos and larvae (Pelletier et al 1997(Pelletier et al , 2000. In general, exposure to high concentrations of PAHs is harmful to the exposed organisms who can bioaccumulate (1992) y se cuantificaron por espectrometría de absorción atómica de grafito (Perkin-Elmer 4100 ZL) (Cobelo-García et al 2005). Los resultados se expresaron en mg kg -1 de peso seco.…”

“…To determine trace metals (Ni, V, Cd, Pb, Cr, Co), the sediments were digested as described by Loring and Rantala (1992), and quantified by graphite furnace atomic absorption spectrometry (Perkin-Elmer 4100 ZL) (Cobelo-García et al 2005). The results are given in mg kg -1 dry weight.…”