FATE OF MERCURY IN THE ARCTIC Michael Evan ... - COGCI

Fate of Mercury in the Arctic 60
a permanent pink colour was obtained, in order to maintain an oxidizing environment and prevent
loss of Hg. The samples were then diluted with 18 MΩ water to approximately 25 g in polyethylene
bottles. Mercury concentrations were determined following reduction with sodium borohydride in a
flow injection AAS system, Perkin Elmer FIMS. The data set obtained using this procedure is in
good agreement with the data obtained using the LECO AMA 254, on average, for Southern
Greenland and Denmark, within 15%, r2 = 0.727, n=65. The total mercury data for Nordvestø is
also being controlled in the above manner. Total mercury in peat from the Faroe Islands was
controlled at the University of Maine Department of Geology, Dr. Steve Norton, using hydride
generation atomic fluorescence spectrophotometry after acid dissolution. Each of these
collaborators also independently measured additional material from the sampling sites as part of the
total investigation.
Total lead and other trace elements were determined using X-ray fluorescence on powders.
Subsamples were dried overnight at 105 0 C in a drying oven, or in the case of high Arctic peat,
freeze dried, and milled in a centrifugal mill equipped with a Ti rotor and 0.25 mm Ti sieve,
Ultracentrifugal Mill ZM 1-T, F. K. Retsch GmbH and Co., Haan, Germany. The Energy-dispersive
Miniprobe Multielement Analyzer (EMMA) using Mo Kβ as the exciting radiation was thereafter
used to non-destructively measure selected major and trace elements (Pb, As, Fe, Mn, Ti, Zr, K, Ca,
Cr, Ni, Cu, Zn, Br, Rb, Sr, Y). Calibration, lower limits of detection, accuracy, and precision of the
method are given elsewhere (Shotyk et al., 2000).
Additional physical and chemical analyses of the samples were performed to verify the
trophic state of the peat. These are detailed in the papers in Appendix C and will not be discussed
here.