广西岩溶洞穴大气中有机氯农药分布与传输

以广西桂林大岩洞穴为例对岩溶洞穴大气环境中有机氯农药污染进行研究.结果表明,洞外大气中OCPs含量为1.82~2.01 ng.m-3,远高于洞内大气中总OCPs含量(范围为0.27~0.83 ng.m-3).大气中有机氯农药浓度呈现从洞口到洞内逐渐降低的趋势,尤其HCHs表现更为明显,表明外界大气传输对洞内污染贡献占主导作用.洞内大气OCPs浓度与两极相当,可作为有机氯农药的背景点.洞穴大气中HCH同系物浓度分布与其本身降解速率大小相吻合,表明在洞穴特有的原始环境下HCH类化合物可较好地反映出自身性质的差异.同时,异构体分布表明周围有新近使用的三氯杀螨醇,HCH类农药以历史残留为主.

Distribution Character of Organochlorinated Pesticides in the Karst Cavity Atmosphere from Guilin City,South China

The investigation was performed on organochlorinated pesticides (OCPs) pollution in karst cavity atmosphere in Guilin City,South China. The total concentrations of OCPs outside the cave atmosphere ranged from 1.82 to 2.01 ng·m^-3,were far more than those of inside cave (range of 0.27-0.83 ng·m^-3). OCPs concentrations fell gradually from cave gate to inside,especially to HCH,which reflected outside atmospheric transportation contributed most of pollutants inside cave. OCPs concentrations inside cave equaled to those in South and North poles therefore could be considered as background for OCPs research. The concentrations distribution sequence of HCH isomers corresponded to degradation rates themselves and that might provide critical information on the exhibiting their inherent character differences of HCH pesticides well under peculiarly original surrounding. In addition,a possibly fresh introduction of discofol-type and a historical usage potential for HCH pesticides in studied area were identified by isomer percentage combined isomer ratios.