【摘要】 主要研究了黄淮海地区7个县的典型农业土壤中六六六(HCH)和滴滴涕(DDT)在每个县的空间分布特征,及其在4个土壤剖面的垂直分布模式。空间分布图表明,HCHS(HCHS=-αHCH+-βHCH+γ-HCH+-δHCH)和DDXS(DDXS=4,4-′DDE+4,4-′DDD+2,4-′DDT+4,4-′DDT)各浓度在每个县的分布基本上是随机的,DDT的变异性大于HCH。DDXS浓度超过国家规定的土壤环境质量一级标准(50μg kg-1)的区域集中在禹城县的东部。该研究同时表明在制定具体的土壤有机氯农药管理措施前研究它们的空间变异性的必要性。HCHS在剖面30 cm以下的含量水平与表层相似,其异构体中以-βHCH的含量最高;而DDXS则主要集中在土表0~30 cm,大于30 cm深度其值显著降低或低于检测限。结果表明在官方禁用20多年后,HCH和DDT在黄淮海地区0~100 cm土壤剖面的含量在绝大部分地点已经降至安全水平。更多还原

【Abstract】 Spatial variability of HCH（HCH_S=α-HCH+β-HCH+γ-HCH+δ-HCH） and DDT（DDX_S=4,4′-DDE +4,4′-DDD+2,4′-DDT+4,4′-DDT）in typical agricultural soils of 7 counties located in the Huang-Huai-Hai Plain,China was examined,and vertical distribution pattern of the residues in 4 soil profiles investigated.Their distribution maps clearly indicated that the residues varied nearly randomly in distribution in these counties.DDT showed stronger variability than HCH.Soils with DDX_S contents exceeding 50 μg kg^-1,the upper limit specified by the Chinese government for the first-class soil quality,all distributed in the east part of Yucheng County.The study revealed the necessity of determining spatial variability in status of organochlorine pesticide for planning a correspondent management programme.The contents of HCH_S at layers deeper than 30 cm were quite similar to what was found in the surface layer 0～30 cm in depth,with β-HCH dominating among its isomers.While,DDX_S was concentrated in the surface layer,0～30 cm in depth,but remained less than the detection limit or decreased markedly with depth.The results indicated that HCH and DDT residues in 0～100 cm soil profiles had declined down to safety level in most sites 20 years after the official ban.更多还原