The general objective is to assess time trends and deposition loads of mercury and persistent organic pollutants from long-range atmospheric transport in Arctic environments (Greenland and north Swedish mountains) using lake sediments. The specific aims are: 1. Mercury - Study pre-industrial and industrial temporal changes in Hg concentrations in sediment records of remote lakes in Greenland and north Swedish mountains. - Address the hypothesis of 'cold condensation' (the progressive re-volatilization in relatively warm locations and subsequent condensation and deposition in cooler environments) of mercury, using a series of lake sediment cores along climate gradients: in Greenland from the inland ice sheet towards the coast and in the Swedish mountains from high altitudes down to the boreal forest. 2. POPs - Make a screening to establish which persistent organic pollutants are present in recent lake sediments in remote sites in Greenland and the north Swedish mountains. Besides PCBs, HCH, DDT and other pesticides, there are new environmental threats such as brominated flame retardants, such as PDBEs, which are of particular interest. The increasing use of PBDE and other brominated compounds may lead to increasing concentrations in the Arctic environment. However, very little is known about the levels of PBDEs as well as other POPs in sediments from the Arctic. - Analyse test series of selected POPs using a lake sediment core to assess temporal trends and a number of surface sediment samples from different lakes to assess spatial variability in concentrations and cumulative fluxes of POPs in Greenland and Swedish mountain lakes. - The main purpose of this pilot study of POPs is to determine the concentrations of selected POPs in sediments from Greenland and the northern Swedish mountains and to assess how useful lake sediments are for studying temporal and spatial pollution loads of POPs in Arctic environments.
Lake sediments cored with a combination of gravity, freeze and Russian peat corers. Hg analyses using CVAFS and POPs with high-resolution GC/MS.