MP7 Global Fate of POPs
Room 18C/D, Level 4
2:10 PM - 5:30 PM, Monday, 10 November 2003
Chair: Lohmann, Rainer ,
Co-chair: Dachs, Jordi ,
(141) Comparison of oceanic air-water exchange, dry and wet deposition fluxes of POPs at the global scale.
Jurado, E1, Jaward, F2, Lohmann, R2, Jones, K2, Dachs, J1, 1 IIQAB-CSIC, Barcelona, Spain2 Lancaster University, Lancaster, UK
ABSTRACT- Air-water exchange and atmospheric wet and dry deposition processes are key processes driving the distribution and transport of Persistent Organic Pollutants (POPs) at the global scale. The relative importance of each process is a function of the pollutant physical-chemical properties and the magnitude of biogeophysical variables such as wind speed, precipitation, etc. For example, dry deposition dominates as a depositional process for the more chlorinated dibenzo dioxins and furans and polycyclic aromatic hydrocarbons, which are sorbed preferentially to the particle-bound phases. Conversely, air-water exchange is the major transfer route of polychlorinated biphenyls from the atmosphere to the ocean. The objective of this study is to assess the relative importance of air-water exchange, dry deposition and wet deposition over the ocean at the global scale. This work is based on atmospheric field measurements of PAHs, PCBs and PCDD/Fs during north-south Atlantic Ocean transects. Remote sensing estimations of temperature, rain precipitation, wind speed, particle size distributions and novel parameterizations of size-dependent dry deposition velocities air-water exchange and wet deposition are used to estimate the magnitude of the transfer of POPs from the atmosphere to the ocean. This approach allows to estimate, for the first time, the spatial distribution and relative importance of wet deposition, air-water exchange and dry deposition over the oceans and at the global scale.
Key words: Air-Water exchange, Environmental modelling, Dry deposition, Wet deposition