| Ship-board air samples were collected during the winter and spring cruise to the Pearl River Estuary (PRE) and adjacent South China Sea (SCS) in 2003 and were analyzed for organochlorine pesticides (OCPs). Meanwhile, air samples were collected at land-based sites in Guangzhou and Zhongshan for comparison. Results indicated that the detected OCPs were mainly of HCHs, DDTs and chlordane, its concentration ranged between 13-99, 73-390, 63-224 pg/m3 and 10-106, 429-1 003, 1 724-9 638 pg/m3 during the winter and spring cruise, respectively. In general, the concentrations of OCPs were higher during spring cruise than in winter cruise. The measured OCPs concentration in the atmosphere over the PRE and adjacent SCS were found higher at sites close to continent and lower in outer sea, it is suggested that land-based source were to play a key role in the delivery of atmospheric OCPs. The α-HCH concentrations had significantly declined, higher γ-HCH level may attribute to the present usage of lindane. Dicofol application and antifouling paints for fishing ships was suggested to be the important current “fresh" DDT source. The observed high level of chlordane during spring cruise could be related to the large amount usage of chlordane for termite control, as well as the long range transport from the west pacific region. |
