Mass budget and dynamics of polychlorinated biphenyls in the eastern Mediterranean Sea

TitleMass budget and dynamics of polychlorinated biphenyls in the eastern Mediterranean Sea
Publication TypeJournal Article
Year of Publication2005
AuthorsMandalakis, M, Apostolaki M, Stephanou EG, Stavrakakis S
JournalGlobal Biogeochemical Cycles
Pages1 - 16

Polychlorinated biphenyls (PCBs) were measured in dry deposition and sediment trap samples from the eastern Mediterranean and the results of the present and previous studies were synthesized in order to construct a mass balance budget describing the status and dynamics of PCBs in this region. According to our calculations, the burden of total PCBs in the euphotic zone of the eastern Mediterranean should approach 84,000 kg, while the corresponding pool in the overlying atmosphere should be about 162 kg. The atmospheric input of PCBs in the respective water basin through dry and wet deposition should be 300 and 1300 kg yr -1, respectively. On the contrary, air-sea exchange should cause a net volatilization of PCBs from seawater to the atmosphere by 3150 kg yr -1. Moreover, PCBs are removed from the water column with a settling flux of 350 kg yr -1 and under steady state conditions, an additional input of these pollutants should be required to counterbalance the outflows from the water basin. The discharge of urban and industrial sewage, riverine input and transport of more polluted surface waters from western to eastern Mediterranean may account for most of this inflow. In the atmospheric compartment, the removal flux of PCBs due to their destruction by hydroxyl radicals (6650 kg yr -1) was approximately 4 times higher than their deposition flux (wet plus dry). On the basis of these data, 5100 kg of PCBs should enter into the atmosphere of eastern Mediterranean annually in order to achieve steady state conditions. This influx may result from long or short range transport of atmospheric PCBs emitted from contaminated terrestrial surfaces. Copyright 2005 by the American Geophysical Union.


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