Pre-industrial and recent (1970-2010) atmospheric deposition of sulfate and mercury in snow on southern Baffin Island, Arctic Canada.
Sulfate (SO4(2-)) and mercury (Hg) are airborne pollutants transported to the Arctic where they can affect properties of the atmosphere and the health of marine or terrestrial ecosystems. Detecting trends in Arctic Hg pollution is challenging because of the short period of direct observations, particularly of actual deposition. Here, we present an updated proxy record of atmospheric SO4(2-) and a new 40-year record of total Hg (THg) and monomethyl Hg (MeHg) deposition developed from a firn core (P2010) drilled from Penny Ice Cap, Baffin Island, Canada. The updated P2010 record shows stable mean SO4(2-) levels over the past 40 years, which is inconsistent with observations of declining atmospheric SO4(2-) or snow acidity in the Arctic during the same period. A sharp THg enhancement in the P2010 core ca 1991 is tentatively attributed to the fallout from the eruption of the Icelandic volcano Hekla. Although MeHg accumulation on Penny Ice Cap had remained constant since 1970, THg accumulation increased after the 1980s. This increase is not easily explained by changes in snow accumulation, marine aerosol inputs or air mass trajectories; however, a causal link may exist with the declining sea-ice cover conditions in the Baffin Bay sector. The ratio of THg accumulation between pre-industrial times (reconstructed from archived ice cores) and the modern industrial era is estimated at between 4- and 16-fold, which is consistent with estimates from Arctic lake sediment cores. The new P2010 THg record is the first of its kind developed from the Baffin Island region of the eastern Canadian Arctic and one of very few such records presently available in the Arctic. As such, it may help to bridge the knowledge gap linking direct observation of gaseous Hg in the Arctic atmosphere and actual net deposition and accumulation in various terrestrial media.
Department of Earth Sciences, Uppsala University, Villavägen 16, Uppsala 75646, Sweden. Electronic address: christian.zdanowicz@geo.uu.se.
Christian
C
Zdanowicz
Inuit Circumpolar Council of Canada, 75 Albert St., Suite 1001, Ottawa, ON K1P 5V5, Canada.
Eva
E
Kruemmel
Lean Environmental, P.O. Box 309, Apsley, ON K0L 1A0, Canada.
David
D
Lean
Department of Biology, University of Ottawa, 30 Marie Curie, Ottawa, ON K1N 6N5, Canada.
Alexandre
A
Poulain
Département des Sciences de l'Environnement, Université du Québec à Trois-Rivières, 3478, Léon-Provancher, Trois-Rivières, QC G9A 5H7, Canada.
Christophe
C
Kinnard
Department of Biology, University of Ottawa, 30 Marie Curie, Ottawa, ON K1N 6N5, Canada.
Emmanuel
E
Yumvihoze
State Key Laboratory of Environmental Geochemistry, Chinese Academy of Sciences, 46 Guanshi Road, Guiyang 550002, China.
JiuBin
J
Chen
Department of Chemistry, Trent University, 1600 West Bank Drive, Peterborough K9J 7B8, Canada.
Holger
H
Hintelmann
D000393:Air Pollutants / Q000032:analysis*; D000397:Air Pollution / Q000706:statistics & numerical data*; D001110:Arctic Regions; D001272:Atmosphere; D002170:Canada; D004784:Environmental Monitoring; D046448:Ice Cover / Q000737:chemistry; D008628:Mercury / Q000032:analysis*; D012914:Snow / Q000737:chemistry; D014874:Water Pollutants, Chemical / Q000032:analysis
D000393:Air Pollutants; D014874:Water Pollutants, Chemical; D008628:Mercury
Air pollution; Arctic; Climate change; Glaciers; Ice; Mercury; Snow