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| Titel |
Step changes in persistent organic pollutants over the Arctic and their implications |
| VerfasserIn |
Y. Zhao, T. Huang, L. Wang, H. Gao, J. Ma |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1680-7316
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| Digitales Dokument |
URL |
| Erschienen |
In: Atmospheric Chemistry and Physics ; 15, no. 6 ; Nr. 15, no. 6 (2015-03-31), S.3479-3495 |
| Datensatznummer |
250119584
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| Publikation (Nr.) |
 copernicus.org/acp-15-3479-2015.pdf |
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| Zusammenfassung |
| While some persistent organic pollutants (POPs) have
been declining globally due to their worldwide ban since the 1980s, the
declining trends of many of these toxic chemicals become less significant
and in some cases their ambient air concentrations, e.g., polychlorinated
biphenyls (PCBs), showed observable increase during the 2000s, disagreeing
with their declining global emissions and environmental degradation. As part
of the efforts to assess the influences of environmental factors on the
long-term trend of POPs in the Arctic, step change points in the time series
of ambient POP atmospheric concentrations collected from four arctic
monitoring sites were examined using various statistical techniques. Results
showed that the step change points of these POP data varied in different
years and at different sites. Most step change points were found in
2001–2002 and 2007–2008. In particular, the step change points
of many PCBs for 2007–2008 were coincident with the lowest arctic sea ice
concentration occurring during the 2000s. The
perturbations of air concentration and water–air exchange fluxes of several
selected POPs averaged over the Arctic, simulated by a POP mass balance
perturbation model, switched from negative to positive during the early 2000s,
indicating a tendency for reversal of POPs from deposition to volatilization
which coincides with a positive to negative reversal of arctic sea ice
extent anomalies from 2001. Perturbed ice–air exchange flux of PCB 28 and
153 showed an increasing trend and a negative to positive reversal in
2007, the year with the lowest arctic sea ice concentration. On the other
hand, perturbed ice–air exchange flux of α-hexachlorocyclohexane
decreased over the period of 1995 to 2012, likely owing to its
lower Henry's law constant which indicates its relatively lower tendency for
volatilization from ice to air. |
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