黄淮海地区典型农业土壤中六六六(HCH)和滴滴涕(DDT)的残留量研究 Ⅰ.表层残留量及其异构体组成

RESIDUES OF HCH AND DDT IN TYPICAL AGRICULTURAL SOILS OF HUANG-HUAI-HAI PLAIN, CHINA Ⅰ. RESIDUES IN SURFACE SOILS AND THEIR ISOMERIC COMPOSITION

定量分析了黄淮海平原典型农业区七个县的129个表层土壤样品中的六六六(HCH)和滴滴涕(DDT)含量以及它们的异构体组成,以全面了解该区域农业土壤中有机氯的当前含量水平和评估其潜在的环境毒害能力。结果表明,所有样品均能检测出不同含量水平的HCHs(HCHs=α-HCH+β-HCH+γ-HCH+δ- HCH),平均为4.01±2.21 pg kgll;DDXs(DDXs=4,4’一DDE+4,4’.DDD+2,4’DDT+4,4’一DDT)的检出率为93%,平均含量为11.16±17.29μgkg-1;所有样品的HCHs均远低于国家规定的土壤环境质量一级标准(50μg kg-1),但有3.1%的样品的DDXs值超过该级标准。与国内的天津、欧洲、美国等农业土壤相比较,黄淮海平原农业土壤的有机氯农药污染现象总体来说并不严重。HCH的4种异构体中,β-HCH含量最高,平均浓度为2.48±1.88μg kg-1;而4,4’-DDE是4种DDT异构体中含量最高的,平均浓度为6.91±13.67μg kg-1。各化合物与土壤有机质之间几乎没有相关性。

Contents of HCH and DDT were measured and their isomeric compositions were investigated in 129 soil samples of typical agricultural surface soils gathered from 7 counties in the Huang-Huai-Hai Plain, China, to understand the present status of residues of the organochlorine pesticides commonly used in the past and to assess their potential toxicology to the environment. HCHs（HCHs = α-HCH ＋ β-HCH ＋ γ-HCH ＋ δ-HCH）was detected in all the samples analyzed, with an average content （ ＋ SD） of 4.01 （2.21） μg kg^-1, while DDXs（DDXs=4, 4＇-DDE ＋4, 4＇-DDD＋2, 4＇-DDT＋4, 4＇-DDT）was found in 93% of the samples, with an average content （ ± SD） of 11.16 （ ± 17.29） μg kg^-1. The former was found far less than 50 μg kg^- 1 in these samples, while the latter exceeding 50 μg kg^- 1 in 3.1% of the samples, an upper limit of the norms for HCH and DDT set by the state for quality of the first-class soil. Generally, agricultural soils from the Huang-Huai-Hai Plain were less contaminated with organochlorine pesticides than the samples from Tianjin, Europe, and USA. The highest contents of β-HCH （with mean ± SD value of 2.48 ± 1.88 μg kg^-1） among 4 HCH isomers and of 4, 4＇-DDE （with mean ± SD value of 6.91 ± 13.67 μg kg^- 1 ） among 4 DDT isomers were observed. Pesticide residues were not proportional to soil organic matter.