The origin and transport of pollutant lead (Pb) to the Svalbard area of the Arctic

Full text: Monitoring of pollutants in the biota of the Arctic is a high priority activity of the circumpolar Arctic nations. Considerable, research has been directed at understanding the influence of pollutants on the Arctic ecosystem. The majority of research in the Svalbard area of the Arctic has concentrated on the levels of persistent organic pollutants (POPs) such as PCBs in the biota of the area. More recently the role of heavy metal pollutants such as mercury (Hg), cadmium (Cd) and lead (Pb) in the arctic ecosystem has been highlighted. A possible major sink/source for contaminants are sediments however very little research has been undertaken in the sediments of the Svalbard area. To fully understand the system and allow preventative or remedial steps to be taken, it is necessary to determine the magnitude of pollutant inputs and the major transport pathways. By investigating sediment cores from lakes, fjordic and shelf environments surrounding the Svalbard area it will be possible to understand these processes and assess their importance in modelling the fate of contaminants within the Arctic environment. By utilising stable Pb isotopes (206Pb, 207Pb and 208Pb) it is possible to identify the source from which it came. For example, in the UK, Pb from petrol has a 206Pb/207Pb ratio of 1.092, industrial sources have a ratio of around 1.18, and natural sources vary but are typically around 1.20. Therefore by measuring the isotopic ratio of the Pb contained in the Svalbard sediments it is possible to determine what the predominant sources of pollutant Pb are. Sediment cores from a north-south transect (Voering Plateau to the Yermak Plateau) and from an east-west transect (Kongsfjorden to Fram Strait) have been analysed for trace element and heavy metal concentrations and stable Pb isotope ratios. To determine the relative importance of atmospheric transport versus marine transport sediment lake cores have been analysed and compared with the cores from Kongsfjorden and the shelf area. Both inventories of Pb and profiles of Pb isotopes from a latitudinal transect (Voering Plateau to the Yermak Plateau) and a longitudinal transect (Kongsfjorden to Fram Strait) and an Arctic lake will be presented. By utilising the stable Pb isotopic signature, the source and the amount of anthropogenic Pb being delivered to the area have been realised. From the results of this study the authors will demonstrate that the predominant source of anthropogenic Pb in Svalbard region is of European origin and extends to higher latitude than the Canadian Arctic. They also conclude that the marine sediment cores demonstrate the influence of north Atlantic circulation on the transport of Pb to the Arctic and that the highest concentrations of anthropogenic Pb are found in continental margin sediments adjacent to the Barents shelf. Finally they demonstrate that the fjordic sediments appear to have low concentrations of anthropogenic Pb which maybe due to dilution by high accumulation rates. (author)