土壤及果树中HCH和DDT残留及分布规律研究

采用索氏提取、弗罗里土固相微萃取小柱净化结合GC-ECD测定了苹果园土壤和果树样品中4种六六六(HCH)和4种滴滴涕(DDT)的残留量,并对果树的根、枝、叶中HCH和DDT的分布规律进行了研究。实验结果表明,土壤和果树样品中均有HCH和DDT检出。土壤样品中两类农药的含量分别在0.51～3.97ng/g和1.46～15.55ng/g之间,其中β-HCH是六六六残留的主体,滴滴涕类的含量以p,p'-DDT为最高,并且(DDE+DDD)/DDT<1表明近期果园中有新的DDT输入。果树样品中,HCH和DDT的残留量分别在0.22～2.01ng/g和0.38～6.08ng/g之间,都要低于相应土壤中有机氯农药的浓度。果树中总OCPs的含量在4.88～17.94ng/g之间,是土壤和大气中OCPs污染共同作用的结果。根部的OCPs的含量明显高于枝和叶,其分布规律为根>叶>枝,这主要取决于根、枝、叶各组织的结构以及农药的理化性质。

Residues and Distributions of HCH and DDT in Orchard Soil and Apple Trees

HCH and DDT were extracted by Soxhlet extraction,purified through Florisil columns and determined by GC-ECD in orchard soil and different tissues of apple trees(leaves,stems,roots).The concentrations of HCH and DDT in soil were 0.51～3.97ng/g and 1.46～15.55ng/g respectively,with β-HCH and p,p'-DDT being the main composition for HCH and DDT.The ratio of(DDE+DDD)/DDT less than 1 implied recent input of DDT in the environment.The levels of HCH and DDT in vegetative samples were in the ranges of 0.22～2.01ng/g and 0.38～6.08ng/g,which are lower than in the corresponding soil.The total concentrations of OCPs in apple trees reached 4.88 ～17.94ng/g resulting from the pollution of soil and atmosphere.The distribution pattern of OCPs in apple trees was roots>leaves>stems.It mainly depended on the structures of roots,leaves,stems and pesticide nature.