商洛城郊公路两侧农作物及其根际土壤重金属污染

Heavy metal pollution of crops and rhizosphere soil on both sides of roads in Shangluo

【目的】为了研究商洛城郊公路两侧的农作物及其根际土壤重金属的污染状况.【方法】以商洛城郊公路312国道和203省道两侧的农作物及其根际土壤为研究对象,测定农作物及其根际土壤中Zn、Cu、Cd、Ni、Mn、Fe重金属含量,分析农作物重金属富集、转运特征.【结果】土壤中Cd污染最为严重(远超出陕西省土壤背景值),其次是Cu,再次是Zn,而Ni、Mn、Fe含量均未超标.不同农作物及其不同部位Cu、Cd、Ni含量均超标,表现为多种重金属混合污染.农作物不同器官对不同重金属的富集能力差异显著,含量依次为Cd>Ni>Cu>Zn>Fe>Mn.公路两侧区域农作物对Cu、Cd、Zn超富集,尤其叶菜类蔬菜吸附重金属的能力较强.【结论】同一农作物对重金属Cu、Zn、Cd、Ni、Mn、Fe富集能力存在高度显著差异,而转运能力存在不显著差异.不同农作物对同种重金属富集能力存在不显著差异,而转运能力存在极显著差异.

【Objective】In order to find out the status of heavy metal pollution in crops and soils on both sides of highways in the suburban of Shangluo.【Method】The samples of crops and rhizosphere soil were collected from the field on both sides of national highway G312 and provincial highway S203 and the contents of Zn,Cu,Cd,Ni,Mn and Fe were measured.【Result】Cd pollution was the most serious which was far higher than the soil background value in Shaanxi Province,which was followed by Cu and Zn.Meanwhile,the contents of Ni,Mn and Fe were lower than the standard.The contents of Cu,Cd and Ni in different crops were all higher than the standard and showed a mixed pollution caused by different heavy metals.Different organs of all tested crops had significant differences in enrichment capacity of different heavy metals,and the order of contents was Cd>Ni>Cu>Zn>Fe>Mn.The tested crops had a strong ability to absorb heavy metals such as Cu,Cd and Zn,especially leafy vegetables.【Conclusion】The same crop showed significant difference in the enrichment ability of Cu,Zn,Cd,Ni,Mn and Fe,and there was no significant difference in transshipment capability.There was no significant difference between different crops in the enrichment ability of same heavy metal,but the transport capacity was significantly different.