苏州、无锡和南通城市地表灰尘中的有机氯农药

Organochlorine pesticides in road dust from Suzhou,Wuxi and Nantong

2009年7月在江苏省南部城市苏州,无锡和南通采集了58个城市地表灰尘样品,使用加速溶剂萃取、气相色谱质谱法测定了样品中的22种有机氯农药(OCPs).结果表明,样品中有19种OCPs被检出,总OCPs含量为76.6μg/kg.六氯苯(HCB)、总滴滴涕(DDTs)和氯丹是样品中检测出的主要OCPs,检出率分别为100%、100%和82.8%,含量分别为26.8μg/kg(0.432~348μg/kg)、39.6μg/kg(1.95~559μg/kg)和6.17μg/kg(ND^145μg/kg).城市地表灰尘样品与中国城市大气样品中检测出OCPs的种类基本一致,而各化合物之间的比例不同.与郊区农田土比较,地表灰尘中检测出的OCPs种类多且含量高.样品中(DDD+DDE)/DDTs的比值显示地表灰尘中的DDT大部分已经降解.城市地表灰尘中的HCB含量较高,工业污染来源可能性较大,工业污染源释放的HCB已经通过大气传输影响到了城区.城市地表灰尘中的反式-氯丹与顺式-氯丹的比值平均为1.94,表明城市中仍有新近使用氯丹的现象.

Organochlorine pesticides （OCPs） were measured in 58 road dust samples collected from Suzhou, Wuxi and Nantong in southern Jiangsu Province. The samples were extracted using accelerated solvent extraction （ASE） and analyzed with gas chromatography^mass spectrometry. 19 OCPs were detected with an average total concentration of 76.6μg/kg. Hexachlorobenzene （HCB）, dichlorodiphcnyltrichlorocthanes （DDTs） and chlordane were identified to be the predominant components of OCPs, and the average concentration were 26.8μg/kg （0.432-348μg/kg）, 39.6μg/kg （1.95-559μg/kg） and 6.17μg/kg （ND-144μg/kg）, respectively, with detection rates of 100%, 100% and 82.7%. The OCPs types detected in road dust samples were consistent with those in ambient air samples collected from cities of China, while the compositional fraction of the major components were different. More species and much higher levels of OCPs were found in road dust samples than those in soil samples collected from rural farmland. The ratio of （DDE＋DDD）/DDT suggested that most DDT in road dust had been degraded. Relatively high concentration of HCB in samples was observed, which was likely due to the emissions and transport of pollutants from the industrial sources. The mean ratio of trans-chlordane （TC） and cis-chlordane （CC） was determined to be 1.94, indicating a newly consumption of chlordane in some areas.