Pine needles as biomonitors of polybrominated diphenyl ethers and emerging flame retardants in the atmosphere of Shanghai, China: occurrence, spatial distributions, and possible sources.

In this study, pine needles were used as biomonitors to investigate the levels, spatial distributions, and possible sources of polybrominated diphenyl ethers (PBDEs) and four emerging halogenated flame retardants (HFRs) in the atmosphere of Shanghai, China. The four emerging HFRs were hexabromocyclododecane (HBCD), decabromodiphenylethane (DBDPE), 1,2-bis(2,4,6-tribromophenoxy) ethane (BTBPE), and dechlorane plus (DP), with the first 3 HFRs being non-polybrominated diphenyl ether brominated flame retardants (non-PBDE BFRs). The total concentrations ranged from 3.71 to 4020 ng g dry weight (dw) for 52 PBDE congeners (ΣBDEs), < MDL (method detection limit) to 15.2 ng g dw for three non-PBDE BFRs (Σnon-PBDE BFRs), and 0.815 to 1090 pg g dw for two DP isomers (ΣDP), respectively. High levels of PBDEs, three non-PBDE BFRs, and DP were found in pine needles from suburbs and Pudong, which was a consequence of industrial activities. The fraction of anti-DP isomer (f) in pine needles ranged from 0.515 to 0.939 with a mean value of 0.721, and most of the f values were consistent with those of technical DP formulations. Principal component analysis-multiple linear regression (PCA-MLR) model identified four sources of PBDEs in pine needles with the quantified contributions: degradation of technical PBDE formulations (49.5%), technical deca-BDE (6.9%), technical penta-BDE (25.1%), and technical octa-BDE (18.5%). These findings are expected to help understand the pollution level, fate, and possible sources of HFRs in the atmosphere of Shanghai and provide a basis for air pollution control and management in Shanghai.