PARENT SESSION

1G - Long-range transport of pollutants (chemicals)
Poster Hall
8:30 AM - Wednesday, 30 April 2003
Chair: Jones, K.C.¹, ¹

(WEP/2) Assessment of the latitudinal and seasonal capacity of the surface ocean as a reservoir of persistent organic pollutants.

Jurado, Elena¹, Dachs, Jordi ¹, Lohmann, Rainer², Meijer, Sandra^{1, 2}, Jones, Kevin², ¹ Dept. of Environmental Chemistry, IIQAB-CSIC, Barcelona, Catalunya, Spain² Environmental Sciences Dept. Lancaster University, Lancaster, Lancaster, United Kingdom

ABSTRACT- The oceans play an important role as a reservoir and as an ultimate sink of persistent organic pollutants (POP) at the global scale. However, the physical and biogeochemical variables that affect the oceanic capacity to retain POPs show an important spatial and temporal variability which have not been studied in detail, so far. The objective of this study is to assess the seasonal and spatial variability of the maximum capacity of the oceans to act as a reservoir of previously atmospherically transported and deposited POPs. This assessment is done by applying a fugacity model (Level I) using the temporal and spatial variability of environmental variables, such as temperature, phytoplankton biomass, mixed layer depth, etc, determined from remote sensing and from climatological datasets. It is found that in addition to temperature, both phytoplankton biomass and mixed layer depth influence the potential role of the oceans as a reservoir of POPs. Furthermore, the estimated maximum capacities to hold POPs are compared with the budged of POPs in the surface oceans as predicted using a level III model that assumes steady state and where water column settling fluxes are the major sink or removal process of POPs. The results confirm that settling fluxes are an important sink and may keep the actual surface oceanic reservoir of POPs well below its maximum capacity, specially for the more hydrophobic POPs. Finally, the strong seasonal and latitudinal variability of the maximum capacity to hold POPs may play an important role in the global biogeochemical cycles controlling the ultimate sink of POPs.

Key words: global dynamics, Persistent organic pollutants, oceans, biogeochemistry