Seaweed Alaria esculenta as a biomonitor species of metal contamination in Aughinish Bay (Ireland)

The concentrations of ten metals (As, Cd, Cu, Fe, Hg, K, Na, Pb, Sn and Zn) were monitored in coastal seawater and biomass of the seaweed Alaria esculenta from Aughinish Bay on the West coast of Ireland during March-June 2014 in order to study their temporal variations and assimilation efficiencies and to assess the ecological quality of these ecosystems. Seawater and A. esculenta showed significant temporal variations in their metal concentrations during March-June 2014 and A. esculenta accumulated more efficiently Fe and Zn, but showed low sensitivity to Na and K. On the other hand, A. esculenta showed no active detoxication mechanisms for Cd and Pb, but no saturation point was observed during this work to any metal. Considering metal concentrations bioaccumulated by A. esculenta, the Irish coast of Aughinish Bay was always ecologically classified as “Class I - Unpolluted” during March-June 2014. The significant correlations between seawater and A. esculenta obtained to all metals proved that this seaweed species: (i) is a suitable biomonitor of metal contamination in Irish coasts; (ii) it can be included in the European Environmental Specimen Banks and (iii) it can be used in European Real-Time Environmental Monitoring Networks.