中文摘要：

分冬、春航次采集了珠江口及南海北部近海海域大气样品,同时以广州和中山作为陆基对照点,对大气中的有机氯农药（OCPs）进行了系统分析.结果表明,大气中的有机氯农药主要为HCHs、DDTs和氯丹,其含量范围分别为13--99、73--390、63--224 pg/m^3（冬季航次）和10--106、4291--003、1 7249--638 pg/m^3（春季航次）.总体而言,春季航次期间的大气OCPs含量普遍高于冬季航次.研究发现,珠江口及南海近海海域大气OCPs主要受控于陆源污染的影响,呈现近陆点高和远陆点低的特点.大气中α-HCH的含量已显著降低,而高含量γ-HCH的检出与林丹的继续使用有关,＂新＂DDT的污染主要来自三氯杀螨醇的生产和使用以及船舶防污油漆中使用的滴滴涕.春季航次期间大气氯丹含量的高值,源于白蚁高发期氯丹的大量使用以及来自西太平洋地区的大气长距离输送.

英文摘要：

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/m^3 and 10-106, 429-1 003, 1 724-9 638 pg/m^3 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.