摘 要：
为了探究有机氯农药(Organochlorine Pesticides,OCPs)在农田土壤中的分布及残留污染特征,2014-2016年利用ASE萃取技术,使用GCPMS方法测定了九龙江流域农田(水田、果园、菜地)土壤主要OCPs,同时采用相关分析和主成分分析方法,研究九龙江流域农田土壤OCPs残留的影响因素及其污染特征。结果表明,该流域农田土壤中残留的有机氯农药主要是六六六(HCHs)、滴滴涕(DDTs)和六氯苯(HCB),其中HCHs是土壤残留有机氯农药的主要成分;氯丹(TC+CC)、九氯(TN+CN)、硫丹(α-End+β-End)残留量较低,是普遍存在的一类持久性有机污染物。有机氯农药均随土层深度的增加而急剧降低,并且随深度的增加其降低幅度逐渐增加,垂直分布表现出明显的"表聚性",相同土层OCPs含量基本表现为水田>果园>菜地。DDTs含量平均值顺序基本表现为o,p′-DDT>p,p′-DDT>p,p′-DDD;其中o,p′-DDT是DDT类污染物的主体物质。HCH含量基本表现为β-HCH>α-HCH>γ-HCH>δ-HCH;其中β-HCH和α-HCH占比相对较高,具有较高的潜在危害性;而α-HCH/γ-HCH比值小于1,存在较多的γ-HCH残留。主成分分析显示,α-HCH、β-HCH、γ-HCH和δ-HCH在第一主成分上有较高载荷;DDTs类物质在第二主成分上有较高载荷;TC和CC、α-End和β-End、TN和CN在第三主成分上有较高载荷。Pearson相关分析表明,TOC与HCHs、HCB、OCPs呈极显著正相关(P<0.01),与α-End和β-End呈显著正相关(P<0.05),与DDTs相关性不显著(P>0.05),说明九龙江流域农田土壤HCHs、HCB含量在很大程度上受TOC影响,HCHs与HCB、DDTs,HCB、DDTs与九氯(TN+CN)类农药的分布机制和输入来源可能一致,在决定有机氯农药含量和分布上起着重要的作用。
译 名：
Characteristics of Organochlorine Pesticide Residues in Farmland Soils of the Jiulong River Watershed
作 者：
LIANG Yu-lan;Minxi Vocational and Technical College;
单 位：
LIANG Yu-lan%Minxi Vocational and Technical College
关键词：
Jiulong River watershed;;organochlorine pesticides(OCPs);;agricultural soils;;OCP residue
摘 要：
Organochlorine pesticide(OCP)residues in soils are primary among environmental pollutants and are receiving increasing national and international attention because of the threat they pose to environmental and human health.In this study,we analyzed the distribution and characteristics of OCP residues in the soil of farmland in the Jiulong River watershed,focusing on their level,composition and vertical distribution.The study was based on soil monitoring of OCPs from 2014 to 2016at 20 sampling sites representing different soil types and land use.Soil samples were collected at different depths(0-10,10-20,20-30cm),and extracted using accelerated solvent extraction(ASE)and determined by gas chromatography.Hexachlorocyclohexanes(HCHs),dichlorodiphenyltrichloroethane(DDT)and hexachlorobenzene(HCB)made up 99.40% of the total OCP residues,with HCHs accounting for 56.01%.Chlordane(TC+CC),(TN+CN)and endosulfan(α-End+β-End)residues were low and pose little threat to the farmland soil in the Jiulong River watershed.The OCP levels were concentrated in the surface layer(0-10cm)and decreased dramatically with soil depth,displaying obvious surface accumulation.The OCP level in the same layer of soil in order of land use was paddy>orchard>vegetable.The average level of DDT isomers was in the order o,p′-DDT>p,p′-DDT>p,p′-DDD and dominated by o,p′-DDT.The average level of HCH residuals was in the orderβ-HCH>α-HCH>γ-HCH>δ-HCH and the levels ofβ-HCH andα-HCH are potentially harmful.Principle component analysis revealed thatα-HCH,β-HCH,γ-HCH andδ-HCH had highest loading in the first principal component,DDTs the highest loading in the second principal component and TC and CC,α-End andβ-End,TN and CN the highest loading in the third principal component.Pearson correlation analysis shows that TOC had an important effect on the level and distribution of OCPs in the soil of farmland in the Jiulong River watershed and the correlation of OCPs,HCHs and HCB with TOC was highly significant(P<0.01).HCHs had a similar distribution and input source with HCB and DDTs,while HCB,DDTs and TN+CN were important determinants of OCP content and distribution.
