Spatial and Seasonal Variations of Hexachlorocyclohexanes (HCHs) and Hexachlorobenzene (HCB) in the Arctic Atmosphere
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- 作者：Yushan Su ; Hayley Hung ; Pierrette Blanchard ; Gregory W. Patton ; Roland Kallenborn ; Alexei Konoplev ; Phil Fellin ; Henrik Li ; Charles Geen ; Gary Stern ; Bruno Rosenberg ; Leonard A. Barrie
- 刊名：Environmental Science & Technology
- 出版年：2006
- 出版时间：November 1, 2006
- 年：2006
- 卷：40
- 期：21
- 页码：6601 - 6607
- 全文大小：285K
- 年卷期：v.40,no.21(November 1, 2006)
- ISSN：1520-5851
文摘
Weekly high-volume air samples were collected between2000 and 2003 at six Arctic sites, i.e., Alert, Kinngait,and Little Fox Lake (LFL) in Canada, Point Barrow inAlaska, Valkarkai in Russia, and Zeppelin in Norway.Hexachlorocyclohexanes (HCHs) and hexachlorobenzene(HCB) were quantified in all samples. Comparison showedthat 
-HCH and HCB were homogeneously distributed inthe circumpolar atmosphere and uniform throughoutthe seasons. However, significantly higher atmosphericconcentrations of -HCH and HCB and stronger temperaturedependence of -HCH and 
-HCH were found at LFL inYukon (YK), which is unique among the sites by virtue of itshigh altitude and low latitude, resulting in higherprecipitation rates and summer temperatures. Strongtemperature dependence of - and -HCH at this locationsuggests that secondary emissions, i.e., re-evaporationfrom surfaces, were more important at this site than others.It is hypothesized that a higher precipitation rate at LFLfacilitated the transfer of -HCH from the atmosphere tosurface media when technical HCH was still in use worldwide.On the other hand, higher temperature at LFL enhanced re-evaporation to the atmosphere after the global ban oftechnical HCH. In contrast to -HCH and HCB, largerspatial and seasonal differences were seen for -HCH(a currently used pesticide), which likely reflect theinfluence of different primary contaminant sources ondifferent Arctic locations. Fugacity ratios suggest a netdeposition potential of HCB from air to seawater, whereasseawater/air exchange direction of -HCH varies in thecircumpolar environment.
-HCH and HCB were homogeneously distributed inthe circumpolar atmosphere and uniform throughoutthe seasons. However, significantly higher atmosphericconcentrations of -HCH and HCB and stronger temperaturedependence of -HCH and -HCH were found at LFL inYukon (YK), which is unique among the sites by virtue of itshigh altitude and low latitude, resulting in higherprecipitation rates and summer temperatures. Strongtemperature dependence of - and -HCH at this locationsuggests that secondary emissions, i.e., re-evaporationfrom surfaces, were more important at this site than others.It is hypothesized that a higher precipitation rate at LFLfacilitated the transfer of -HCH from the atmosphere tosurface media when technical HCH was still in use worldwide.On the other hand, higher temperature at LFL enhanced re-evaporation to the atmosphere after the global ban oftechnical HCH. In contrast to -HCH and HCB, largerspatial and seasonal differences were seen for -HCH(a currently used pesticide), which likely reflect theinfluence of different primary contaminant sources ondifferent Arctic locations. Fugacity ratios suggest a netdeposition potential of HCB from air to seawater, whereasseawater/air exchange direction of -HCH varies in thecircumpolar environment.