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Download fileAtmospheric Dry Deposition of Persistent Organic Pollutants to the Atlantic and Inferences for the Global Oceans
journal contribution
posted on 2004-11-01, 00:00 authored by Elena Jurado, Foday M. Jaward, Rainer Lohmann, Kevin C. Jones, Rafel Simó, Jordi DachsAtmospheric deposition to the oceans is a key process
affecting the global dynamics and sinks of persistent organic
pollutants (POPs). A new methodology that combines
aerosol remote sensing measurements with measured POP
aerosol-phase concentrations is presented to derive dry
particulate depositional fluxes of POPs to the oceans. These
fluxes are compared with those due to diffusive air−water exchange. For all polychlorinated biphenyl (PCB)
congeners and lower chlorinated dibenzo-p-dioxins and
furans (PCDD/Fs), air−water exchange dominates the dry
deposition mechanism. However, this tendency reverses
in some areas, such as in marine aerosol influenced areas
and dust outflow regions, consistent with the important
variability encountered for the depositional fluxes. Seasonal
variability is mainly found in mid-high latitudes, due to
the important influence of wind speed enhancing dry
deposition fluxes and temperature as a driver of the gas-particle partitioning of POPs. The average dry aerosol
deposition flux of ΣPCBs and ΣPCDD/Fs to the Atlantic
Ocean is calculated to be in the order of 66 ng m-2 yr-1
and 9 ng m-2 yr-1 respectively. The total dry aerosol deposition
of ∑PCBs and ∑PCDD/Fs to the Atlantic Ocean is estimated
to be 2200 kg yr-1 and 500 kg yr-1, respectively, while
the net air−water exchange is higher, 22000 kg ∑PCBs yr-1
for PCBs and 1300 kg ∑PCDD/Fs yr-1. Furthermore, it is
suggested that marine aerosol plays an important role in
scavenging atmospheric contaminants.