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          Institute: MPI für Meteorologie     Collection: Ocean in the Earth System     Display Documents

ID: 423781.0, MPI für Meteorologie / Ocean in the Earth System
Global environmental cycling of γHCH and DDT in the 1980s: A study using a coupled atmosphere and ocean general circulation model
Authors:Guglielmo, F.; Lammel, G.; Maier-Reimer, E.
Date of Publication (YYYY-MM-DD):2009-09
Title of Journal:Chemosphere
Start Page:1509
End Page:1517
Review Status:Peer-review
Audience:Not Specified
Abstract / Description:A coupled atmosphere-ocean general circulation model, ECHAM5-MPIOM, was used to study the multi-compartmental cycling and long-range transport of persistent and semivolatile organics. Multiphase systems in air and ocean are covered by submodels for atmospheric aerosols, HAM, and marine biogeochemistry, HAMOCC5, respectively. The model, furthermore, encompasses 2D surface compartments, i.e. top soil, vegetation surfaces and sea-ice. The total environmental fate of gamma-hexachlorocyclohexane (gamma-HCH, lindane) and dichlorophenyltrichloroethane (DDT) in agriculture were studied.
DDT is mostly present in the soils, the water-soluble gamma-HCH in soils and ocean. DDT has the longest residence time in almost all compartments. Quasi-steady state with regard to substance accumulation is reached within a few. years in air and vegetation surfaces. In seawater the partitioning to suspended and sinking particles contributes to the vertical transport of substances. On the global scale deep water formation is, however, found to be more efficient. Up to 30% of DDT but only less than 0.2% of gamma-HCH in seawater are stored in particulate matter.

On the time scale studied (1 decade) and on global scale substance transport in the environment is determined by the fast atmospheric circulation. The meridional transport mechanism, for both compounds, is significantly enhanced by multi-hopping. Net meridional transport in the ocean is effective only regionally, mostly by currents along the western boundaries of Africa and the Americas. The total environmental burdens of the substances experience a net northward migration from their source regions, which is more pronounced for DDT than for gamma-HCH. Due to the application distribution, however, after 10 years of simulation 21% of the global environmental burden of gamma-HCH and 12% of DDT have accumulated in the Arctic.
External Publication Status:published
Document Type:Article
Communicated by:Carola Kauhs
Affiliations:MPI für Meteorologie/Ocean in the Earth System
MPI für Chemie
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