The effect of atmosphere-snow-ice-ocean coupling on hexachlorocyclohexane (HCH) pathways within the Arctic marine environment

dc.contributor.authorPucko, Monika
dc.contributor.examiningcommitteeWang, Feiyue (Environment and Geography) Doering, Jay (Civil Engineering) Macdonald, Robie (Environment and Geography) Halsall, Crispin (Lancaster University)en_US
dc.contributor.supervisorStern, Gary (Environment and Geography) Barber, David (Environment and Geography)en_US
dc.date.accessioned2011-08-24T17:04:45Z
dc.date.available2011-08-24T17:04:45Z
dc.date.issued2010
dc.degree.disciplineEnvironment and Geographyen_US
dc.degree.levelDoctor of Philosophy (Ph.D.)en_US
dc.description.abstractThe importance of the cryosphere, and of sea ice in particular, for contaminant transport and redistribution in the Arctic was pointed out in the literature. However, studies on contaminants in sea ice are scarce, and entirely neglect the sea ice geophysical and thermodynamic characteristics as well as interactions between various cryospheric compartments. This thesis addresses those gaps. Ice formation was shown to have a significant concentrating impact on the levels of HCHs in the water just beneath the ice. Both geophysical and thermodynamic conditions in sea ice were shown to be crucial in understanding pathways of accumulation or rejection of HCHs. Although HCH burden in the majority of the ice column remains locked throughout most of the season until the early spring, upward migration of brine from the ice to the snow in the winter has an effect on levels of HCHs in the snow by up to 50 %. In the spring, when snow melt water percolates into the ice delivering HCHs to the upper ocean via desalination by flushing, levels of HCHs in the ice can increase by up to 2 %-18 % and 4 %-32 % for α- and γ-HCH, respectively. Brine contained within sea ice currently exhibits the highest HCH concentrations in any abiotic Arctic environment, exceeding under-ice water concentrations by a factor of 3 in the spring. This circumstance suggests that the brine ecosystem has been, and continues to be, the most exposed to HCHs. α-HCH levels were shown to decrease rapidly in the last two decades in the Polar Mixed Layer (PML) and the Pacific Mode Layer (PL) of the Beaufort Sea due to degradation. If the rate of degradation does not change in the near future, the majority of α-HCH could be eliminated from the Beaufort Sea by 2020, with concentrations in 2040 dropping to < 0.006 ng/L and < 0.004 ng/L in the PML and the PL, respectively. Elimination of α-HCH from sea water takes significantly longer than from the atmosphere, with a lag of approximately two decades.en_US
dc.description.noteOctober 2011en_US
dc.identifier.citationPućko, M.; G. A. Stern; D. G. Barber; R. W. Macdonald, and B. Rosenberg. 2010. The International Polar Year (IPY) Circumpolar Flaw Lead (CFL) System Study: The Importance of Brine Processes for α- and γ-Hexachlorocyclohexane (HCH) Accumulation or Rejection in Sea Ice. Atmosphere-Ocean. 48: 244-262.en_US
dc.identifier.citationPućko, M.; G. A. Stern; R. W. Macdonald, and D. G. Barber. 2010. α- and γ-Hexachlorocyclohexane Measurements in the Brine Fraction of Sea Ice in the Canadian High Arctic Using a Sump-Hole Technique. Environ. Sci. Technol. 44: 9258-9264.en_US
dc.identifier.citationPućko, M.; G. A. Stern; R. W. Macdonald; B. Rosenberg, and D. G. Barber. 2011. The Influence of the Atmosphere-Snow-Ice-Ocean Interactions on the Levels of Hexachlorocyclohexanes (HCHs) in the Arctic Cryosphere. J. Geophys. Res. 116: C02035, doi:10.1029/2010JC006614.en_US
dc.identifier.urihttp://hdl.handle.net/1993/4767
dc.language.isoengen_US
dc.publisherCMOSen_US
dc.publisherAGUen_US
dc.publisherACSen_US
dc.rightsopen accessen_US
dc.subjectcontaminantsen_US
dc.subjectArcticen_US
dc.subjectHCHen_US
dc.subjecticeen_US
dc.titleThe effect of atmosphere-snow-ice-ocean coupling on hexachlorocyclohexane (HCH) pathways within the Arctic marine environmenten_US
dc.typedoctoral thesisen_US
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