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首次对桂林岩溶区洞穴土壤中有机氯农药的污染状况进行了研究。结果表明,洞穴土壤受到了有机氯农药的轻度污染,其中大气传输对有机氯农药的贡献起主导作用。在17种有机氯农药中,以DDTs、HCHs和氯丹污染为主。在洞穴内部OCP总量为1.19～11.18 ng/g,远低于洞外土壤中的含量(11.41～23.62 ng/g)。在洞内土壤中,HCHs含量高于DDTs,在HCH四种同分异构体中,β-HCH占HCHs的比例远高于其他3种同分异构体。除β-HCH外,其他3种同分异构体的含量分布均匀,可能是由洞穴环境稳定、气候分带等因素造成的。在洞外土壤中,异构体百分比和示踪标志物比值表明周围可能有林丹扣三氯杀螨醇的新近输入。研究区六六六和滴滴涕主要来源于历史上使用的农药的残留。
For the first time, the pollution status of organochlorine pesticides in the cave soil of karst area in Guilin was studied. The results showed that the soil in the cave was slightly polluted by organochlorine pesticides, and the contribution of atmospheric transport to organochlorine pesticides played a leading role. Of the 17 organochlorine pesticides, DDTs, HCHs and chlordane were the main pollutants. The total amount of OCP in the cave was 1.19 ~ 11.18 ng / g, much lower than that in the soil outside the cave (11.41 ~ 23.62 ng / g). HCHs contents were higher in soils than in DDTs. Among the four HCH isomers, the proportion of β-HCH to HCHs was much higher than the other three isomers. In addition to the β-HCH, the other three isomers of the content distribution, may be caused by the cave environment is stable, climate zoning and other factors. In off-hole soils, the percentage of isomers and the ratio of tracer markers indicate that there may be a recent input of lindane and dicofol around. The study area BHC and DDT mainly come from the pesticide residues used in history.