树木吸收和富集重金属规律的研究

发布时间：2019-06-17 18:39

【摘要】：本文通过ICP-OES法分析铜陵某矿区内杨树(populus simonii Carr.var.przewalskii(Maxim.)H.L.Yang)和泡桐(Paulownia tomentosa(Thunb.)Steud)内不同部位重金属镉、锌、铜的含量,结合盆栽模拟实验,研究和讨论了杨树和泡桐对三种重金属的吸收差异特征,并着重研究了杨树对重金属镉的吸收和分布特征,为杨树应用于镉污染土壤的治理提供了依据和数据支持。实验结果表明:矿区土壤中镉、锌、铜的含量超过当地的土壤背景值,矿区堆填区附近的土壤中,重金属的含量随着土壤深度的增加而降低。重金属锌在泡桐内部的纵向分布规律为树叶树根树枝树干;铜在泡桐内部的纵向分布规律为树叶树根树枝树干;重金属镉在泡桐体内各器官的分布规律为树根树干树枝树叶。重金属锌在杨树内部的纵向分布规律为树叶树枝树干树根,铜在杨树内部的纵向分布规律为树根树枝树叶树干,重金属镉在杨树体内各器官的分布规律为树叶树根树枝树干。重金属镉在杨树干的含量随着高度的增加而降低,靠近树根的部位镉含量最高。在盆栽模拟实验中我们得出的结论与之完全一致,在镉浓度一致的土壤中,镉在杨树叶中的含量最高,树干中的镉含量随着高度的增加而降低,树干的顶部镉含量最低。同种元素在杨树内部不同器官中的含量各不相同,但三种重金属在杨树树干各部位中的含量虽有不同,纵向的分布规律却基本一致,重金属的含量随着树干纵向高的增加而逐渐降低。重金属镉在杨树内部的径向分布规律为树皮心材边材,盆栽模拟实验得到的结论与之并不完全一致,镉浓度的径向分布规律为树皮边材心材,两次实验中发现,树皮中的镉含量始终是最高的。杨树干内三种重金属的含量锌铜镉;泡桐树干中为锌铜镉,树木同一部位对重金属的富集能力因重金属的种类而存在很大的差异。树木对同种重金属元素的富集能力因树木种类和部位的不同而存在显著的差异。杨树内各部位对镉的富集系数均大于0.12,树叶对镉的富集系数达到0.5以上,叶片中的镉含量最高可达878.26mg/kg。而泡桐内部各器官对镉的富集系数低于0.04,树枝部位的镉含量最低,富集系数为0.03,镉含量为0.092mg/kg。杨树各部位对锌的富集系数均大于0.8,泡桐对锌的富集系数均小于0.1,远低于杨树。而杨树对铜的富集系数大于0.1,泡桐各部位对铜的富集系数大于0.4。杨树对镉和锌的富集能力强于泡桐,对铜的富集能力弱于泡桐。土壤中镉浓度的升高会对杨树对重金属镉的富集能力产生抑制,盆栽模拟实验中,空白对照的树木对镉的富集系数达到10以上,随着土壤中施加的镉浓度的增加,杨树对镉的富集系数逐渐降低,当土壤中的镉含量达到50mg/kg时,杨树对土壤中的镉的富集系数明显降低,土壤镉含量达到100mg/kg时,杨树对镉的富集系数达到0.5以下。不同树木对不同重金属的转运能力也有所不同,泡桐对铜的转运系数均高于1,而杨树对铜的转运系数低于0.35,泡桐将铜从根部转移至其余各部位的能力是杨树的3倍左右。锌在杨树内各部位的转运系数均高于0.9,泡桐内各部位对锌的转运系数高于0.3,泡桐虽然对铜的转运能力强于杨树,但对锌的转运能力却比杨树差。杨树各部位内镉的转运系数均高于0.5,而泡桐对镉的转运系数低于0.25,重金属镉在杨树内部的迁移能力是在泡桐中的2倍。泡桐树叶中不同重金属转运系数之间的关系为锌铜镉,杨树叶中不同重金属的转运系数间的关系为锌镉铜。锌在杨树和泡桐的树叶中迁移性最高,镉在杨树中的转移能力比在泡桐中强,铜在泡桐中的迁移能力比在杨树中的强。在盆栽模拟实验中,随着土壤中施加的镉浓度的变化,杨树各样本之间对镉的转运系数变化不大,当土壤中施加的镉浓度达到5mg/kg时,杨树树干部位对镉的转运系数在0.7~1.5之间浮动,当土壤中的镉浓度达到100mg/kg时,杨树对镉的转运系数仍旧在0.7~1.0之间浮动,土壤中镉浓度的增加对杨树转移镉的能力并未产生明显的抑制作用。总体来看,杨树比泡桐更加适合应用在治理镉污染土壤的过程中。
[Abstract]:In this paper, by means of ICP-OES, the contents of heavy metals, zinc and copper in different parts of a mining area of Tongling were analyzed by means of ICP-OES, the contents of zinc and copper in different parts of Poulus simonii Carr.var.przewalskii (Maxim.) H. L. Yang) and Paulownia tomentosa (Thunb.) Steud were analyzed. The characteristics of the absorption and distribution of the heavy metal salt of poplar are studied, and the basis and data support for the application of the poplar to the treatment of soil polluted by the soil are provided. The results show that the content of iron, zinc and copper in the soil of the mining area exceeds the local soil background value, and the content of the heavy metal in the soil near the filling area of the mining area decreases with the increase of the depth of the soil. The longitudinal distribution of heavy metal zinc in the interior of the paulownia is the tree trunk of the root of the leaves; the longitudinal distribution of the copper in the interior of the paulownia is the tree trunk of the tree root; the distribution of the heavy metal zinc in the organs of the paulownia is the branch of the branch of the tree root. The longitudinal distribution of the heavy metal zinc in the poplar is the tree root of the branch of the leaves, the longitudinal distribution of the copper in the poplar is the tree trunk of the tree root, and the distribution of the heavy metal zinc in the body of the poplar is the tree trunk of the tree root. The content of the heavy metal salt in the trunk of the poplar is decreased with the increase of the height, and the content of the heavy metal salt near the root of the tree root is the highest. In the experiment of pot experiment, we concluded that the content of the tree trunk is the highest in the soil with the same concentration, and the content of the water in the trunk is lower with the increase of the height, and the content of the top of the trunk is the lowest. The content of the same elements in different organs of the poplar is different, but the content of the three heavy metals in different parts of the trunk of the poplar is different, the distribution law of the longitudinal direction is basically the same, and the content of the heavy metal is gradually reduced with the increase of the longitudinal height of the trunk. The radial distribution of heavy metal in the interior of the poplar is the bark core material. The result of the pot experiment is not exactly the same as that of the bark. The radial distribution of the bark concentration is the core material of the bark. In the two experiments, the content of the bark in the bark is always the highest. The content of the three heavy metals in the trunk of the poplar tree is as follows: the content of the three heavy metals in the trunk of the poplar is the same as that of the zinc and the copper, and the concentration of the heavy metal in the same part of the tree is very different due to the type of the heavy metal. The enrichment ability of the tree to the same heavy metal element has a significant difference due to the different species and parts of the tree. The enrichment factor of each part of the poplar is more than 0.12, the enrichment factor of the leaves to the leaf is more than 0.5, and the enrichment factor of the leaves in the leaves is up to 878.26 mg/ kg. The enrichment factor of the internal organs of Paulownia was lower than that of 0.04, the content of the enrichment of the branch was the lowest, the enrichment factor was 0.03, and the content of selenium was 0.092 mg/ kg. The concentration factor of zinc in all parts of poplar is more than 0.8, and the enrichment factor of paulownia to zinc is less than 0.1, which is far lower than that of poplar. And the enrichment factor of the poplar to the copper is more than 0.1, and the enrichment factor of each part of the paulownia to the copper is greater than 0.4. The enrichment ability of poplar to iron and zinc is stronger than that of Paulownia, and the enrichment ability of the copper is weaker than that of Paulownia. The concentration of the poplar in the soil can be restrained by the enrichment ability of the heavy metal salt of the poplar. In the pot experiment, the enrichment factor of the trees in the blank control reaches more than 10, and the accumulation coefficient of the poplar is gradually reduced with the increase of the concentration of the soil applied in the soil. When the content of the soil in the soil reaches 50 mg/ kg, the enrichment factor of the poplar in the soil is obviously reduced, and the enrichment factor of the poplar to the soil reaches below 0.5 when the soil moisture content reaches 100 mg/ kg. The transport capacity of different trees to different heavy metals is also different, and the transport coefficient of paulownia to copper is higher than 1, while the transport coefficient of the poplar to copper is lower than 0.35, and the capacity of the paulownia to transfer the copper from the root to the rest is about 3 times that of the poplar. The transport coefficient of zinc in all parts of poplar was higher than that of 0.9, and the transport coefficient of zinc in all parts of Paulownia was higher than that of 0.3, while the transport capacity of Paulownia was stronger than that of poplar, but the transport capacity of zinc was lower than that of poplar. The transport coefficient of the poplar in each part of the poplar is higher than 0.5, while the transport coefficient of the paulownia to the poplar is lower than 0.25, and the migration capacity of the heavy metal salt in the poplar is 2 times that of the paulownia. The relationship between the transport factors of different heavy metals in the leaves of the pajatropha curcas leaves is a zinc-copper-copper alloy, and the relationship between the transport coefficients of the different heavy metals in the poplar leaves is zinc and copper. The migration of zinc in the leaves of the poplar and paulownia is the highest, the transfer capacity of the copper in the poplar is stronger than that of the paulownia, and the migration capacity of the copper in the paulownia is higher than that of the poplar. In the experiment of pot experiment, with the change of the concentration of the soil applied in the soil, the transfer coefficient of the poplar between the samples is not great, and when the concentration of the water applied in the soil reaches 5 mg/ kg, the transport coefficient of the trunk part of the poplar is floating between 0.7 and 1.5. When the concentration of the soil in the soil reaches 100 mg/ kg, the transport coefficient of the poplar is still between 0.7 and 1.0, and the increase of the concentration of the water in the soil has no obvious effect on the ability of the poplar to transfer. In general, the poplar is more suitable for use in the process of treating and polluting the soil than the paulownia.
【学位授予单位】：安徽农业大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：X53;X173

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