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本研究采用干筛法和重力干沉降法对5种表土进行土粒粒径分离,研究在北京地区的风沙季节,地表土的DDT、BHC量与土粒粒径、有机质量之间的关系。结果表明,土壤残留DDT、BHC农药主要分布在土粒粒径为<0.25mm组分中,其中容易被气流浮动的<0.05mm粒径组分的DDT和BHC量,分别占原来表土量的41—89%和30—81%。在一定粒径范围,粒径越小,DDT、BHC含量越高,且与有机质含量之间呈极显著正相关(P<0.01)。同时,土粒中DDT、BHC及其某些代谢产物和异构体的比例却随土粒粒径的不同而变化。
In this study, the dry-sieving method and the gravity-sedimentation method were used to separate the five kinds of topsoil from each other. The relationship between DDT, BHC and soil particle size and organic mass in surface aeolian seasons in Beijing was studied. The results showed that the residual DDT and BHC pesticides were mainly distributed in <0.25mm soil particle size, of which the DDT and BHC content of <0.05mm particle size easily fluctuated by air flow accounted for 41% -89% and 30-81%. In a certain particle size range, the smaller the particle size, the higher the DDT and BHC contents, and the extremely significant positive correlation with the organic matter content (P <0.01). At the same time, the ratio of DDT, BHC and some of its metabolites and isomers in soil particles varies with the particle size of soil.