Atmospheric DDTs over the North Pacific Ocean and the adjacent Arctic region: Spatial distribution, congener patterns and source implication

During the 2003 Chinese Arctic Research Expedition (CHINARE 2003) from Bohai Sea to the high Arctic (37 degrees N-80 degrees N), air samples were collected and analyzed for DDTs. Sigma DDTs (sum of six congeners) ranged from 0.52 to 265 pg m(-3) with an average of 13.1 pg m(-3). Higher DDT concentrations were observed in Bohai Sea and near eastern Russia. The congener patterns were obviously different between the Far East Asia and the higher latitudinal regions that p,p'-DDT and o,p'-DDT were dominated in the former; while o,p'-DDT and o,p-DDE were dominated in the latter. The source contributions of technical DDT and dicofol type DDT were estimated. Results showed that technical DDT was the dominant source (>94%) which was fresher in the Far East Asia compared to the North Pacific Ocean and the Arctic. For dicofol type DDT, the estimated contribution was minor. The new o,p'-DDT observed should have relatively more contribution from dicofol type DDT in the North Pacific Ocean and the Arctic. (C) 2009 Elsevier Ltd. All rights reserved.