Evidence for dynamic air-water coupling and cycling of persistent organic pollutants over the open Atlantic Ocean.
Ship-board air samples collected between The Netherlands and South Africa in January-February 2001 were analyzed for PCBs and selected organochlorine compounds. Broad latitudinal trends in compound concentrations were influenced by proximity to source areas, land, and air mass origin. Lowest concentrations were observed in the remote south Atlantic (1-32 degrees S), where sigma7PCB concentrations were approximately 10 pg m(-3). Here, a diurnal cycle was noted for some PCB congeners, with the daytime concentrations higher than the nighttime concentrations, typically by a factor of 1.5-2.5. The data are consistent with a close coupling of air-open ocean concentrations, which has important implications for future rates of POP removal from the global "recyclable pool". The observations are discussed in the context of the potential controlling variables. Interactions between the phytoplankton and the dissolved phase are implicated in controlling the observations made here and a hypothesis to explain the cycling trends is presented. However, the precise mechanisms remain unclear; further studies are urgently required to elucidate them.
Jaward
Foday M
FM
Department of Environmental Science, Institute of Environmental and Natural Sciences, Lancaster University, Lancaster, LA1 4YQ, UK.
Barber
Jonathan L
JL
Booij
Kees
K
Dachs
Jordi
J
Lohmann
Rainer
R
Jones
Kevin C
KC
D000393:Air Pollutants / Q000032:analysis; D001267:Atlantic Ocean; D004784:Environmental Monitoring; D004785:Environmental Pollutants / Q000032:analysis*; D007306:Insecticides / Q000032:analysis*; D010839:Phytoplankton; D011078:Polychlorinated Biphenyls / Q000032:analysis*; D012995:Solubility; D014874:Water Pollutants, Chemical / Q000032:analysis
D000393:Air Pollutants; D004785:Environmental Pollutants; D007306:Insecticides; D014874:Water Pollutants, Chemical; D011078:Polychlorinated Biphenyls