成都城区蔬菜地土壤中农药残留及其分布特征

采用GC-ECD检测、GC/MS-MS确证的方法对成都城区14个区县蔬菜地土壤中23种有机氯农药（OCPs）进行分析,以揭示OCPs的残留现状及其分布特征。结果表明,OCPs残留水平在不同区县间差异很大,变化范围20.18～104.33μg.kg-1之间,近郊区县（双流、龙泉驿、郫县、新都、温江）远低于边缘区县。被检出的18种OCPs中,DDTs、HCHs检出率最高（100%）,残留水平为16.11～99.51、1.31～9.34μg.kg-1,分别占OCPs残留总量质量分数的87.68%、8.15%;六氯苯（HCB）次之（90%）;灭蚁灵、环氧七氯、硫丹Ⅰ和γ-氯丹也有不同程度的检出（44.29%～47.14%）,主要分布在近郊区县;艾氏剂、狄氏剂、异狄氏剂、毒杀芬的检出率较低（32.86%～37.14%）,多分布于彭州、都江堰、大邑、崇州等地。土壤中OCPs的各种异构体、代谢物变化规律显示,DDTs、HCHs残留主要源于早期的使用或大气输入,但不排除金堂、青白江、新津地区近期可能有新的DDTs输入,崇州、彭州、都江堰、大邑地区可能有HCHs输入。

Residual of organochlorine pesticides and distribution characteristics in the vegetable soils from Chengdu region of Sichuan province, China

To determine current levels of organochlorine pesticides（OCPs） and to assess their distribution characteristics in vegetable soils,soil samples were collected from fourteen sites in Chengdu region of Sichuan province in July 2010,and twenty-three kinds of OCPs were quantified by means of gas chromatography equipped with a 63Ni electron-capture detector（GC-ECD） system.Results showed that OCPs were found widely in all soil samples and ranged from 20.18 to 104.33 μg·kg-1,and residue levels of OCPs in soils from outskirts of Chengdu（e.g.Shuangliu,Long quan-yi,Pi county,Xindu and Wenjiang） was apparently less than those from outlying counties（e.g.Jintang,Qin bai-jiang,Xinji,Pujiang,Pengzhou,Du jiang-yan,Dayi and Chongzhou）.Among eighteen kinds of OCPs found,including 1,1,1-trichloro-2,2-bis（p-chlorophenyl）ethane（DDT） and its metabolites 1,1-dichloro-2,2-bis（p-chlorophenyl）ethylene（DDE） and 1,1-dichloro-2,2-bis（p-chlorophenyl）ethane（DDD）,hexachlorocyclohexane（HCH） and its isomers（α-,β-,γ-,and δ-HCH）,aldrin,hexachlorobenzene（HCB）,dieldrin,endrin,a-endosulfan,γ-chlordane,heptachlor epoxide,toxaphene and mirex,DDTs and HCHs were detected in all soil samples,with a range of 16.11～99.51 μg·kg-1 for DDTs and 1.31～9.34 μg·kg-1 for HCHs,and were the main components in residues of OCPs,accounting for 87.68% and 8.15% of the total,respectively.Compared to HCB with an occurrence of 90%,a-endosulfan,γ-chlordane,heptachlor epoxide and mirex were detectable in a range of 44.29%～47.14% of all the samples,which mostly collected in the outskirts of Chengdu.However,aldrin,dieldrin,endrin and toxaphene were only found in these sites in northwestern of Chengdu（e.g.Pengzhou,Du jiang-yan,Dayi and Chongzhou）,accounting for 32.86%～37.14% of the collected soil samples.Furthermore,indicated by the changing rule of residues of OCPs,their principal metabolites and isomers,the authors induced that for most area,residues of OCPs in the soils might come from the old usage or long distance trantsportion from their application sites,but there might be input into environment recently in Jintang,Qin bai-jiang and Xinjin regions for DDTs,and so did in Pengzhou,Du jiang-yan,Dayi and Chongzhou regions for HCHs.