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| Titel |
Trends, Long-range Transport and Lifetime of DDT in and over Central Europe |
| VerfasserIn |
G. Lämmel, A. Dvorská, A. Stohl, J. Klánová, L. Ries |
| Konferenz |
EGU General Assembly 2009
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 11 (2009) |
| Datensatznummer |
250023758
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| Zusammenfassung |
| Dichlorophenyltrichloroethane, DDT, and its major metabolites dichlorophenyldichloroethylene,
DDE, and dichlorophenyldichloroethane, DDD, are long-lived in the environment (persistent)
and circulate since the 1950s. They accumulate along food chains, cause detrimental effects
in marine and terrestrial wild life, and pose a hazard for human health. DDT is a
multicompartmental substance with only a small mass fraction residing in air. Decreasing
concentration trends are recorded in Europe, where the substance has not been used since
-1988 (Holoubek et al., 2007). Transport in the free troposphere is expected by models
(Lammel & Semeena, 2005; Semeena et al., 2006), but no observations in the free
troposphere had been reported in Europe. The degradation rates of DDT, DDE and DDD are
uncertain. In particular, the hydroxyl radical reaction rate coefficients in air are
unknown.
DDT monitoring data in air at a central European continental background station,
Kosetice, Czech Republic, were used in combination with back-trajectories (HYSPLIT
model, NOAA) to localize DDT sources in central, western and northern Europe. The
decreasing trend continued during recent years, 2004-06.
During 2 campaigns at a high mountain site in the Alps (Zugspitze, 2650 m a.s.l.) mean
concentrations of 0.23, 0.63 and 0.08 pg m-3 of DDT, DDE and DDD, respectively, were
measured in summer and 0.73, 2.22, and 0.52 pg m-3, respectively, in winter. The levels
were not lower in free tropospheric air than in boundary layer air. Transport and residence
times in air were quantified using Lagrangian particle dispersion model retroplume analyses
(FLEXPART model; Stohl et al., 1998). During a stable anti-cyclonic situation photochemical
lifetimes corresponded to kOH < 1.5x10-12 cm3 molec-1 s-1 are found for p,p’-DDT,
kOH < 0.75x10-12 cm3 molec-1 s-1 for p,p’-DDE and kOH < 1.0x10-12 cm3
molec-1 s-1 for p,p’-DDD. The kOH values for DDE and DDD are significantly lower than
estimated (QSAR).
References:
Holoubek I., Klánová J., Jarkovský J., Kohoutek J. (2007): Assessment of the central
European trends in the background levels of persistent organic pollutants based on
the results of the long-term integrated monitoring in Kosetice observatory, Czech
Republic. Part I. Ambient air and wet deposition 1988-2005, J. Environ. Monitoring 9,
557-563
Semeena V.S., Lammel G. (2005): The significance of the grasshopper effect on the
atmospheric distribution of persistent organic substances, Geophys. Res. Lett. 32, L07804,
doi:10.1029/2004GL022229
Semeena V.S., Feichter J., Lammel G. (2006): Impact of the regional climate and
substance properties on the fate and atmospheric long-range transport of persistent organic
pollutants – examples of DDT and γ-HCH, Atmos. Chem. Phys. 6, 1231-1248
Stohl A., Hittenberger M., Wotawa G. (1998): Validation of the Lagrangian particle
dispersion model FLEXPART against large scale tracer experiment data, Atmos. Environ. 32,
4245-4264 |
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