Occurrence and air-seawater exchange of brominated flame retardants and Dechlorane Plus in the North Sea: Fid-Bau Portal

Occurrence and air-seawater exchange of brominated flame retardants and Dechlorane Plus in the North Sea

Möller, Axel / Xie, Zhiyong / Caba, Armando / Sturm, Renate / Ebinghaus, Ralf

Abstract The occurrence, spatial and seasonal concentration variations in air and seawater and the air–seawater exchange of polybrominated diphenyl ethers (PBDEs), alternate brominated flame retardants (BFRs) and Dechlorane Plus (DP) were studied in the German part of the North Sea in 2010. BDE–209 and DP were found to be the dominating compounds, both in the atmosphere and in seawater. Sum PBDEs (∑10PBDEs) ranged from 0.31 to 10.7 pg m⁻³ in the atmosphere and from not detected (n.d.) to 10.5 pg L⁻¹ in seawater, respectively. DP ranged from 0.13 to 22.3 pg m⁻³ and from 0.10 to 17.7 pg L⁻¹ in air and seawater, respectively. Besides, four other BFRs including hexabromobenzene (HBB) and pentabromobenzene (PBBz) were detected. Elevated atmospheric concentrations were observed in continentally influenced air masses while highest seawater concentrations were observed at sampling stations close to the coast influenced by riverine discharge. The ratio of the two DP stereoisomers both in air and water was found to be close to the technical mixture at high concentrations but changed at lower concentrations giving first evidence for the alteration within the aquatic environment. Both dry air-seawater gas exchange and dry deposition are input pathways of BFRs and DP in the North Sea besides riverine discharge.

Highlights ► BDE–209 and DP are emitted via the atmosphere and rivers into the North Sea. ► High HBB concentrations in the North Sea occur during winter time and northerly winds. ► First evidence for the alteration of the DP stereoisomer ratio in (sea)-water. ► Possible BDE–209 degradates HBB and PBBz detected in the atmopshere. ► Air–seawater exchange in the North Sea is dominated by net deposition.