| Abstract
| - Concentrations of polychlorinated naphthalenes (PCNs)are reported for the first time in arctic air. The data representcombined air samples from the Barents Sea (n = 2),eastern Arctic Ocean (n = 10), Norwegian Sea (n = 2),and two land-based monitoring stations at Alert, Canada (n= 5), and Dunai Island in eastern Siberia, Russia (n =3). Values for ∑PCN (pg m-3) were 6−49 for shipboardsamples and 0.3−8 for land-based stations and weredominated by the 3-Cl and 4-Cl homologues, which accountedfor 90−95% of the total mass. Average values for ∑PCB(pg m-3) for the shipboard samples were 126, 24, and 75 forthe Barents Sea, eastern Arctic, and Norwegian Sea,respectively. Three-dimensional 5-day air parcel back-trajectories arriving at the ship at 850 and 925 hPa suggestedthat elevated PCB and PCN concentrations for shipboardsamples originated in Europe. Concentrations (fg m-3) ofcoplanar PCBs in artic air were 3−40 (PCB 77) and0.3−8 (PCB 126)about an order of magnitude lower thanin urban air. Higher concentrations of PCB 77 and PCB126, 347 and 5.0 (fg m-3), respectively, were found in theBarents Sea for two samples with elevated ∑PCBs. Theproportion of coplanar PCBs to ∑PCBs was within the rangeof values reported for Aroclor and Clophen mixtures.The 2,3,7,8-TCDD toxicity of the air samples was assessedin terms of the TEQ (dioxin toxic equivalents) contributionof mono-ortho PCBs (congeners 105, 114, 118, 156), non-ortho(coplanar) PCBs (congeners 77 and 126), and dioxin-likePCNs for which toxic equivalent factors have been determined.The results show a 13−67% TEQ contribution of PCNs inarctic air, and it is concluded that further investigation of thiscompound class is merited.
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