Air−Water Exchange and Dry Deposition of Polybrominated Diphenyl Ethers at a Coastal Site in Izmir Bay, Turkey

Abstract

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 (∑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 ∑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 (r² = 0.33−0.55, p < 0.05, except for BDE-209, r² = 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.