Long-term changes in heavy metal loadings of Ascophyllum nodosum from the Firth of Clyde,UK

The aim of this work is to describe changes in heavy metal concentrations in Ascophyllum nodosum from 1964 to 1994. Samples were collected from three sites in the Firth of Clyde and analysed for zinc, manganese, iron, copper, lead and nickel. The results were analysed using the multivariate technique Principal Components Analysis (PCA). At the Wemyss Bay site there was a trend towards increasing lead and nickel over the study period, which could not be accounted for by local industrial activity. At the Hunterston site, two groups were well separated by the PCA ordination, based on manganese and zinc concentrations, which corresponded to land reclamation activities in the area. The separation of samples at the Ardneil Bay site correlated well with copper concentration and this corresponded to the termination of industrial effluent with heavy copper loadings. Other changes in industrial effluent were also reflected in the Hunterston and Ardneil Bay site ordinations. The PCA technique highlighted the interplay between metals. The work demonstrated the potential for using multivariate analysis of seaweed metal concentrations in monitoring a posteriori the environmental impact of industrial change.