Title: Atmospheric input of polychlorinated biphenyls to the eastern Mediterranean

Auteur(s): Mandalakis M ; Stephanou E ;  ; 

Year: 2003

Journal: Organohalogen Compounds

Subject(s): polychlorinated ; polychlorinated biphenyls ; PCBs ; PCB ; organochlorine ; Polychlorinated biphenyl ;  ; 

Summary: Pollution throughout Mediterranean was always under special concern. The very high concentrations of PCBs and other xenobiotics in resident marine mammals 1 indicated that the pollution of western Mediterranean has reached alarming levels. Contaminants such as DDT and PCBs were regarded as responsible for the mass die-offs of monk seals and striped dolphins along the Mediterranean coasts. Studies dealing with the mass balance of PCBs in the western Mediterranean Sea have shown that this region is continually acting as a reservoir of organochlorine compounds, while the atmospheric flux of PCBs due to dry and wet deposition account for most of the input. However, the deposition fluxes calculated in these models were based on a limited number of field measurements4. Indeed, several chlorinated hydrocarbons including PCBs were formerly detected in a limited number of deposition samples, collected in south France. Since PCBs are semivolatile compounds, they exist in both gas and particulate phases of the atmosphere. Thus, both gaseous and particle-associated PCBs can be deposited on earth's surf ace through precipitation scavenging. In the absence of precipitation, particulate and gaseous PCBs can also be removed from the atmosphere due to dry deposition processes. Polychlorinated biphenyls were recently measured in dry and wet deposition samples collected from a marine, background station of northeastern Crete, Greece and the corresponding atmospheric fluxes were calculated. The flux of gaseous PCBs due to air-water exchange was also estimated by Liss and Slater model based on previously reported atmospheric data. In the present study we investigate the contribution of each individual process to the atmospheric input of PCBs to eastern Mediterranean Sea. Furthermore, the washout ratio and the dry deposition velocity of PCBs were calculated and are also discussed.