Mercury in dated Greenland marine sediments

Twenty marine sediment cores from Greenland were analysed for mercury, and dated by the lead-210 method. In general the cores exhibit a mercury profil e with higher mercury concentrations in the upper centimetres of the core. The cores were studied by linear regression of In Hg vs, age of the sedimen t for the youngest 100 years. As a rule the mercury decreased with depth in the sediment with various degrees of significance. The increase of the mer cury flux during the last 100 years is roughly a doubling. The increase may be of anthropogenic origin as it is restricted to the last 100 years. In f our cores the concentration of manganese was found also to increase in the top layers indicating diagenesis. In the other cases the higher concentrati ons were not accompanied by higher manganese concentrations. The mercury fl ux to the sediment surface was generally proportional to the Pb-210 flux in dicating that the mercury mainly originates from atmospheric washout. But t he large variability indicates that other processes also influence the merc ury flux to Arctic marine sediments. (C) 2000 Elsevier Science B.V. All rig hts reserved.