不同污染梯度下城市主要绿化树种香樟重金属富集效能研究

发布时间：2018-06-12 19:31

本文选题：香樟 + 树干　；参考：《浙江农林大学》2017年硕士论文

【摘要】：本文以浙江永康市城市常见绿化树种香樟为研究对象,根据不同污染梯度在研究区内设置12个样地,分别采集植物地上部分(树叶、树枝、树干)样品共计108个及植物根际土壤样品36个,利用ICP-OES测定植物样品中Cu、Zn、Pb、Cr、Mn、Ni六种重金属元素浓度,分析城市绿化树种对Cu、Zn、Pb、Cr、Mn、Ni六种重金属元素的吸收作用,以及各重金属元素在香樟各器官中的分布特征,探讨不同污染梯度下植物对重金属元素的富集特征,研究结果显示:(1)香樟树叶和树枝重金属元素浓度大小顺序均为MnZnCuCrPbNi,香樟树干重金属元素浓度大小顺序为MnZnCrPbNiCu,树叶中重金属Mn元素的浓度和树干中Pb、Cr、Ni元素的浓度明显高于其它重金属元素在各器官中浓度。(2)香樟各器官对不同重金属元素的富集系数大小顺序具有一定差异,其中树叶对Mn、树干对Pb和Ni具有明显的富集能力;各器官在不同土壤重金属浓度梯度下,总体呈现随土壤重金属浓度梯度的升高富集系数逐渐下降的趋势。(3)胸径为22cm的单株香樟地上部分总积累量为18935.36 mg,各器官积累量的大小顺序为树叶树干树枝,积累量分别为7920.75 mg、6202.21 mg和4812.40mg,香樟树干对重金属元素Cu、Zn、Pb、Cr、Ni的富集效能显著高于其它器官,分别占地上部分总积累量的59.72%、61.80%、81.62%、71.09%和91.89%,富集效能较明显。(4)利用香樟树干对不同等级的重金属污染土壤的修复年限进行预测,树干对Cu、Pb、Ni的重度污染土壤修复年限分别为15年/hm2、42年/hm2和56年/hm2,树干对Cr、Zn的修复年限较长分别为135年/hm2和219年/hm2。(5)研究区内香樟根际土壤存在重金属Cr污染,且污染程度达到中度污染等级,Cu、Zn、Ni、Pb达到轻污染等级,Mn在安全范围内。香樟对重金属元素Mn、Cu、Cr、Ni的富集系数均随土壤污染梯度的升高而降低,而重金属元素Zn、Pb的富集系数均随土壤污染梯度的升高而升高。
[Abstract]:Taking camphor camphora, a common greening tree species in Yongkang City, Zhejiang Province as the research object, 12 plots were set up in the study area according to different pollution gradients, and the above ground parts (leaves, branches, branches) of plants were collected separately. A total of 108 tree trunks and 36 rhizosphere soil samples were collected. The concentrations of six heavy metals in plant samples were determined by ICP-OES, and the absorption of six heavy metal elements by urban greening tree species was analyzed. The distribution characteristics of heavy metal elements in different organs of Cinnamomum camphora were also discussed, and the enrichment characteristics of heavy metal elements in plants with different pollution gradients were discussed. The results showed that the concentration order of heavy metal elements in leaves and branches of camphor tree was MnZnCuCrPbNi. the order of concentration of dry metal elements of camphor tree was MnZnCrPbNiCu. the concentration of heavy metal mn in leaves and the concentration of PbPbPbNiin in tree trunk were obviously higher. The enrichment coefficient of different heavy metal elements in different organs of Cinnamomum camphora varied with the concentration of other heavy metal elements in different organs. Among them, leaves have obvious enrichment ability to mn, trunk to Pb and Ni. As a whole, the accumulation coefficient decreased with the increase of soil heavy metal concentration gradient. The total accumulation of the aboveground part of Cinnamomum camphora with DBH of 22cm was 18935.36 mg, and the order of accumulation of each organ was tree branch of leaf trunk. The accumulations were 7920.75 mg / g 6202.21 mg and 4812.40 mg / g respectively. 59.72% of the total accumulated amount of the aboveground part was 61.80% and 71.09% and 91.89%, respectively, and the enrichment efficiency was obvious. 4) the remediation years of soils contaminated by heavy metals of different grades were predicted by using the stem of camphor tree. The remediation life of heavily polluted soil from trunk to Cu PbN was 15 years / hm ~ 2, 42 / hm ~ 2 and 56 years / hm ~ 2, respectively, and the restoration life of tree trunk to Cr-Zn was 135 / hm ~ 2 / hm ~ 2 and 219 / hm ~ 2 / hm ~ (5) respectively. There was Cr pollution in the soil of Cinnamomum camphora rhizosphere in the study area. And the pollution degree reached the moderate pollution grade. The content of Cu ~ (2 +) Zn ~ (2 +) Ni ~ (2 +) Pb reached the light pollution grade (mn) in the safe range. The enrichment coefficient of heavy metal mn _ (Cu) Cu _ (Cr) Cr ~ (2 +) Ni of Cinnamomum camphora decreased with the increase of soil pollution gradient, while the enrichment coefficient of heavy metal element Zn ~ (+) Pb increased with the increase of soil pollution gradient.
【学位授予单位】：浙江农林大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：X173;S792.23

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