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| Titel |
Transport and fate of hexachlorocyclohexanes in the oceanic air and surface seawater |
| VerfasserIn |
Z. Xie, B. P. Koch, A. Möller, R. Sturm, R. Ebinghaus |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1726-4170
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| Digitales Dokument |
URL |
| Erschienen |
In: Biogeosciences ; 8, no. 9 ; Nr. 8, no. 9 (2011-09-19), S.2621-2633 |
| Datensatznummer |
250006125
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| Publikation (Nr.) |
 copernicus.org/bg-8-2621-2011.pdf |
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| Zusammenfassung |
| Hexachlorocyclohexanes (HCHs) are ubiquitous organic pollutants derived from
pesticide application. They are subject to long-range transport, persistent
in the environment, and capable of accumulation in biota. Shipboard
measurements of HCH isomers (α-, γ- and β-HCH) in
surface seawater and boundary layer atmospheric samples were conducted in
the Atlantic and the Southern Ocean in October to December of 2008. ΣHCHs concentrations
(the sum of α-, γ- and β-HCH) in
the lower atmosphere ranged from 12 to 37 pg m−3 (mean: 27 ± 11 pg m−3)
in the Northern Hemisphere (NH), and from 1.5 to 4.0 pg m−3
(mean: 2.8 ± 1.1 pg m−3) in the Southern Hemisphere (SH),
respectively. Water concentrations were: α-HCH 0.33–47 pg l−1,
γ-HCH 0.02–33 pg l−1 and β-HCH 0.11–9.5 pg l−1. Dissolved HCH
concentrations decreased from the North Atlantic to the Southern Ocean,
indicating historical use of HCHs in the NH. Spatial distribution showed
increasing concentrations from the equator towards North and South latitudes
illustrating the concept of cold trapping in high latitudes and less
interhemispheric mixing process. In comparison to concentrations measured in
1987–1999/2000, gaseous HCHs were slightly lower, while dissolved HCHs
decreased by factor of 2–3 orders of magnitude. Air-water exchange gradients
suggested net deposition for α-HCH
(mean: 3800 pg m−2 day−1) and γ-HCH (mean: 2000 pg m−2 day−1),
whereas β-HCH varied between equilibrium
(volatilization: <0–12 pg m−2 day−1) and net deposition
(range: 6–690 pg m−2 day−1). Climate change may significantly accelerate the release of
"old" HCHs from continental storage (e.g. soil, vegetation and high
mountains) and drive long-range transport from sources to deposition in the
open oceans. Biological productivities may interfere with the air-water
exchange process as well. Consequently, further investigation is necessary
to elucidate the long term trends and the biogeochemical turnover of HCHs in
the oceanic environment. |
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