Air-water exchange and dry deposition of polybrominated diphenyl ethers at a coastal site in Izmir Bay, Turkey

The air-water exchange of polybrominated diphenyl ethers (PBDEs), an emerging class of persistent organic pollutants (POPS), was investigated using paired air-water samples (n = 15) collected in July and December, 2005 from Guzelyali Port in Izmir Bay, Turkey. Total dissolved-phase water concentrations of PBDEs (Sigma 7PBDEs) were 212 +/- 65 and 87 +/- 57 pg L-1 (average +/- SD) in summer and winter, respectively. BDE-209 was the most abundant congener in all samples, followed by BDE-99 and -47. Average ambient gas-phase Sigma 7PBDE concentrations were between 189 +/- 61 (summer) and 76 +/- 65 pg m(-3) (winter). Net air-water exchange fluxes ranged from -0.9 +/- 1.0 (BDE-28) (volatilization) to 11.1 +/- 5.4 (BDE-209) ng m(-2) day(-1) (deposition). The BDE-28 fluxes were mainly volatilization while the other congeners were deposited. Gas- and dissolved-phase concentrations were significantly correlated (r(2) = 0.33-0.55, p < 0.05, except for BDE-209, r(2) = 0.05, p > 0.05) indicating that the atmosphere controls the surface water PBDE levels in this coastal environment. Estimated particulate dry deposition fluxes ranged between 2.7 +/- 1.9 (BDE-154) and 116 +/- 84 ng m(-2) day(-1) (BDE-209) indicating that dry deposition is also a significant input to surface waters in the study area.