Concentrations, Fluxes, and Residence Time of PBDEs Across the Tropical Atlantic Ocean

Little is known about the fate of polybrominated diphenylethers (PBDEs) across the Oceans. Air and water were sampled using both active and passive polyethylene samplers on an east-west transect across the tropical Atlantic Ocean in 2009 and analyzed for PBDEs. Typical particle-bound concentrations of PBDEs in the surface water were low, at <1 pg L-1. Truly dissolved concentrations from passive samplers were similar to 40.5 pg L-1 for BDE 47 and around 0.1 pg L-1 for BDEs 28, 99, and 100 (results from active samples were compromised). In the atmosphere, particle-bound BDE 209 dominated overall concentrations (median 1.2 pg m(-3)), followed by BDE 99 (0.13 pg m(-3)). Gas-phase concentrations based on passive samplers were 1-8 pg m(-3) for BDE 47 and <= 4 pg m(-3) for BDE 99. Net air-water exchange gradients strongly favored gas-phase deposition of PBDEs into the water. Net gas-phase deposition fluxes ranged from tens of pg m(-2) day(-1) for BDEs 28 and 85 to around 1 ng m(-2) day(-1) for BDE 47, 99, and 209. Settling fluxes of particle-bound PBDEs in the atmosphere and surface water were around 50 pg m(-2) day(-1) for BDE 47 and <10 pg m(-2) day(-1) for the other congeners.