Polybrominated diphenyl ethers in precipitation in Southern Sweden (Skåne, Lund)

The presence of polybrominated diphenyl ether (PBDE) flame retardants in total deposition (wet+dry) was assessed with the simultaneous use of three bulk samplers during a 2 week period. The particle associated and the ‘dissolved’ phase were separated during sampling. Volume weighted mean (VWM) concentrations of ∑PBDE (9 congeners) in rain were 209 pg l−1. Total deposition rates were 2±1 ng ∑PBDE m−2 day−1. The total PBDE deposition was dominated by decaBDE(209) and thereafter 2,2′4,4′-tetraBDE(47) and 2,2′4,4′,5-pentaBDE(99). Concentrations of particle associated and ‘dissolved’ PBDEs in total deposition were used to calculate filter/adsorbent ratios (F/A). We found that 65±18% of the total PBDEs were particle associated. Low F/A ratios for higher brominated congeners (Br>5) were observed. This is contradictory with predictions based on the PBDEs’ physico-chemical properties and was attributed to sampling artefacts, such as particle size distribution, and/or non-equilibrium processes. There was a negative relationship between the particulate ∑PBDE concentration and rain volume suggesting a dilution effect and the importance of particle scavenging for wet deposition of PBDEs.