Copper, nickel, and vanadium in the Western Galician Shelf in early spring after the Prestige catastrophe: is there seawater contamination?

Abstract

The original cargo fuel transported by the Prestige tanker, according to our analysis, contained several trace elements, for example Cu (3 μg g⁻¹), Ni (97 μg g⁻¹), and V (382 μg g⁻¹). The possibility of metal contamination of seawater near the bottom from the sedimented fuel and in surface waters from the fuel deposited on the littoral area was researched in the Western Galician Shelf 5 months after the Prestige shipwreck (November 2002). Water samples obtained at eight stations from Finisterre Cape to Miño River were analysed by means of an electroanalytical method (AdCSV) and following trace-metal-clean procedures. Only the surface Cu and Ni levels at the Ons and Cíes Islands were higher than those considered as background for Open North East Atlantic Ocean waters. The accumulation and weathering of the fuel deposited on the shores could be a significant source for the enrichment found, but the influence of industrial and urban inputs from the neighbouring Pontevedra and Vigo rias is also possible. Thus, this study was useful for establishing typical values of Cu, Ni, and V in Galician Shelf waters for the first time. Total metal concentrations ranged between 1.7 and 3.4 nmol L⁻¹ for Cu, between 2.9 and 4.8 nmol L⁻¹ for Ni, and between 19.7 and 32.3 nmol L⁻¹ for V; dissolved concentrations were between 0.7 and 1.5 nmol L⁻¹ for Cu, between 2.2 and 3.3 nmol L⁻¹ for Ni, and between 15.5 and 27.0 nmol L⁻¹ for V; particulate values below 2.6 nmol L⁻¹ for Cu, 2 nmol L⁻¹ for Ni, and 7.2 nmol L⁻¹ for V were obtained.