Contrasting the seasonal variability of halogenated natural products and anthropogenic hexachlorocyclohexanes in the southern Norwegian atmosphere.

Halogenated natural products (HNPs) are increasingly recognized as compounds of marine environmental samples. In this study, we explored whether the annual course of the concentrations of HNPs in ambient air samples was different from those of anthropogenic pollutants. For this purpose, air samples taken weekly at Lista, southern Norway, were analyzed by gas chromatography-mass spectrometry for anthropogenic aaeeee- (alpha-HCH) and aaaeee-hexachlorocyclohexane (gamma-HCH, lindane) isomers, as well as the HNPs 2,3,3',4,4',5,5'-heptachloro-1'-methyl-1,2'-bipyrrole (Q1), 2,4-di- and 2,4,6-tribromoanisole (24-DBA, 246-TBA), and 2,4,6-tribromophenol (246-TBP). Concentrations of HCH isomers were higher in the warmer summer months than in winter. By contrast, Q1, 24-DBA, 246-TBA, and 246-TBP showed much higher concentrations at the end of the year. Correlations between the concentrations of the compounds and air mass trajectories as well as further meteorological data are discussed. An unknown mixed halogenated substance was detected at high abundance during the summer months. High-resolution mass spectrometry and tandem mass spectrometric techniques were used to unravel the molecular structure, which was found to be C(7)H(8)Br(3)Cl, an elemental composition never reported before in the scientific literature.