Elemental and chemometric analysis of baseline gradient contamination in Usnea barbata lichens from Tierra del Fuego (South Patagonia)

In order to provide an updated baseline assessment of elemental concentrations in native lichens samples collected at eight selected sampling sites from Tierra del Fuego (South Patagonia), we have determined the concentration of more than forty elements in Usnea barbata by means of different analytical techniques (INAA, ICP-MS, ICP-OES, AMA and CV-AFS), and compared the results in order to ensure reliable data at the moment to perform a comprehensive management of pristine environments. New chemometrics approaches have been employed to identify different tracers of anthropic activities, highlighting their possible gradient concentration and providing a environmental management tool. Overall, most of elements’ concentration were comparable with recent literature, with the exception of Br, Hg, Li and Lu. Subsequently, multivariate data analysis has been performed on the data-set to highlight a possible natural grouping of samples. HCA and PCA pointed out the presence of three clusters, while variables selection pointed out nineteen elements as the most influencing of the clustering. A concentration decrease of Sb and Sn from cluster 1(containing a site situated close to Ushuaia and its International Airport) to cluster 3 was found. These elements’ concentration is related to anthropogenic activities, such as combustive processes, vehicular traffic, waste burning and dust resuspension. The results here presented confirmed that TdF is still a slightly contaminated environment. Furthermore, the elements’ concentration reported in this paper could be considered as baseline levels useful for environmental management, in term of prevention and protection.