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| Titel |
Progress in Global Multicompartmental Modelling of DDT |
| VerfasserIn |
I. Stemmler, G. Lämmel |
| 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 |
250023873
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| Zusammenfassung |
| Dichlorophenyltrichloroethane, DDT, and its major metabolite dichlorophenyldichloroethylene,
DDE, 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 was widely used as an insecticide in the past and is
still in use in a number of tropical countries to combat vector borne diseases like malaria and
typhus. It is a multicompartmental substance with only a small mass fraction residing in
air.
A global multicompartment chemistry transport model (MPI-MCTM; Semeena et al., 2006)
is used to study the environmental distribution and fate of dichlorodiphenyltrichloroethane
(DDT). For the first time a horizontally and vertically resolved global model was used to
perform a long-term simulation of DDT and DDE. The model is based on general circulation
models for the ocean (MPIOM; Marsland et al., 2003) and atmosphere (ECHAM5). In
addition, an oceanic biogeochemistry model (HAMOCC5.1; Maier-Reimer et al., 2005 ) and
a microphysical aerosol model (HAM; Stier et al., 2005 ) are included. Multicompartmental
substances are cycling in atmosphere (3 phases), ocean (3 phases), top soil (3 phases), and
vegetation surfaces. The model was run for 40 years forced with historical agricultural
application data of 1950-1990.
The model results show that the global environmental contamination started to decrease
in air, soil and vegetation after the applications peaked in 1965-70. In some regions, however,
the DDT mass had not yet reached a maximum in 1990 and was still accumulating mass until
the end of the simulation.
Modelled DDT and DDE concentrations in atmosphere, ocean and soil are
evaluated by comparison with observational data. The evaluation of the model results
indicate that degradation of DDE in air was underestimated. Also for DDT, the
discrepancies between model results and observations are related to uncertainties of input
parameters. Furthermore, better resolution of some processes could improve model
performance.
References:
Marsland S.J., Haak H., Jungclaus J.H., Latif M., Röske F. (2003): The Max-Planck-Institute
global ocean/sea ice model with orthogonal curvilinear coordinates. Ocean Modelling 5,
91–127
Maier-Reimer E. , Kriest I., Segschneider J., Wetzel P. : The HAMburg Ocean Carbon
Cycle Model HAMOCC 5.1 - Technical Description Release 1.1 (2005),Reports on Earth
System Science 14
Stier P. , Feichter J. (2005), Kinne S., Kloster S., Vignati E., Wilson J.Ganzeveld L.,
Tegen I., Werner M., Blakanski Y., Schulz M., Boucher O., Minikin A., Petzold A.: The
aerosol-climate model ECHAM5-HAM. Atmos. Chem. Phys 5, 1125-1156
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 |
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