沈阳城市土壤-旱柳-降尘系统中铅、镉的分布迁移特征研究

Analysis on Distribution and Migration Characteristics of Pb and Cd in Soil,Plant and Dust fall in Urban Region of Shenyang City

目前,城市土壤中重金属污染研究仍是一个热点问题,大气降尘作为土壤-植物系统中重金属的重要来源之一,关于降尘对土壤-植物系统的影响研究则较少,对沈阳城市土壤、大气降尘、旱柳中的铅、镉分布特征研究表明:城市表土中铅含量在8.82～93.9 mg kg-1之间,镉含量在0.62～5.28 mg kg-1之间;城市土壤铅、镉含量在剖面均表现出相同的分布特点,且剖面迁移不明显。不同季节降尘中铅、镉含量变化为冬季>春季>秋季。旱柳中铅含量为叶片>枝条,镉含量为枝条>叶片。大气降尘铅含量分别与城市表土和旱柳叶片铅含量呈极显著相关,镉含量与旱柳叶片中镉含量呈极显著相关;旱柳枝条中镉含量与0～100 cm土壤镉含量呈极显著相关。

Now,the heavy metal pollution in urban soil is still a hot issue.As one of primary source of heavy metal,there is a little study on connection among urban soil,plant and dust fall.The distribution of Pb and Cd contents in urban soil and dust fall of Shenyang were studied in this paper.The results were as follows.The range of Pb content in urban soil was 8.82-93.9 mg kg-1.The range of Cd content in urban soil was 0.62-5.28 mg kg-1.There was the same characteristic of Pb and Cd in soil profile.The migration of Pb and Cd in soil profile was not obvious.The contents of Pb and Cd in winter were highest,the second was in spring and the lowest was in autumn.The content of Pb in leaves of Salix matsudana L was higher than that in caudexes.The content of Cd in caudexes was higher than that in leaves.The content of Pb in dust fall was extremely significantly correlated with those of soil and leaves of Salix matsudana L..The content of Cd in dust fall was significantly correlated with the content of Cd in leaves of Salix matsudana.L..The content of Cd in caudexes of Salix matsudana.L.was extremely significantly correlated with that in 0-100 cm layer of soil.