漓江沉积柱芯有机氯农药垂向分布特征与来源

用GC/ECD内标法定量法首次测定了广西桂林漓江沉积柱中19种有机氯农药(OCPs)的含量,结果表明:漓江沉积柱芯中OCPs浓度范围为4.75～489.4ng/g(均值43.26ng/g),在国内处于中等污染水平。OCPs、HCHs表现出下游污染程度高于上游,但DDTs则相反,这是由于上游的取样点蚂蟥洲附近有大量餐饮业造成的。沉积柱垂直分布表明,漓江近期受到人为污染影响。总体上漓江沉积物中HCHs污染大于DDTs,符合当地的农药使用历史。同分异构体比值表明研究区DDT主要是历史使用农药残留并得到了较好的降解,且以厌氧生物降解为主,当地在使用三氯杀螨醇可能性不大;沉积物中工业六六六尚未降解完全,同时周围可能有林丹输入。

Distribution Characteristics and Sources of Organochlorine Pesticides in Sediment Cores of Lijiang River

The contents of 19 kinds of organochlorine pesticides（OCPs） in two sediment cores of Lijiang River,Guilin city,were determined using GC-ECD.The total concentration of OCPs was in the range of 4.75～489.4ng/g（mean 43.26ng/g）,showing a middle pollution level in China.OCPs and HCHs showed higher contents in the downriver of Lijiang River than those in upriver,while DDTs were opposite,which caused by mass restaurants locating near the Mahuang Continent（sampling site on the upriver）.Down-core concentrations showed Lijiang River was influenced by anthropogenic pollution.In general,pollution level of HCHs was higher than that of DDTs in sediments,in accordance with the local pesticides usage history.The isomer ratios showed that DDT were aged residue and had been microbially degraded well with a domination of anaerobic condition.Local Dicofol application could not be proved.Industrial BHC in sediments had not completely degraded and lindane might be introduced around.