徐州北郊矿区小麦重金属污染特征研究

发布时间：2018-07-04 17:23

本文选题：小麦 + 重金属　；参考：《中国矿业大学》2015年硕士论文

【摘要】：煤矿生产和利用过程中产生的重金属使附近农田土壤受到污染,通过生物富集导致农作物污染。然而土壤中的重金属含量并不是农作物重金属污染的唯一原因,很多研究结果表明,植物叶片从大气中吸收的重金属也是导致的农作物污染原因之一。因此,查明徐州北郊矿区小麦中重金属污染来源,对矿区重金属污染的治理以及粮食安全管理有着重要意义。本论文通过测定研究区域内成熟期小麦根、茎叶、颖壳、籽实中的重金属含量,评价小麦籽实食用安全性以及人体摄入健康风险;结合相关性分析结果、小麦幼苗对不同环境因子响应实验结果以及污染源调查结果,探讨小麦重金属污染的来源。最终得出以下结论:(1)与我国农业行业标准以及我国粮食卫生标准相比,研究区域内24个采样点位的小麦籽实中Pb、Cd、As、Cr四种重金属分别超标1.65倍、0.10倍、0.60倍、1.51倍,而Cu、Zn两种重金属均未超过标准,重金属空间分布特征表明重金属含量超标与煤矿工业分布关系密切。(2)研究区域内小麦籽实中重金属单因子污染指数特征为:PbCrAsCdCuZn。重金属经口摄入途径对人体造成的健康风险顺序为AsPbCuCdZnCr。Zn、Cu在成熟期小麦不同器官中的含量大小依次为:根部籽实茎叶颖壳;Cd、Pb、As在成熟期小麦不同器官中的含量大小依次为根部颖壳茎叶籽实;而Cr在成熟期小麦不同器官中的含量大小依次为颖壳茎叶根部籽实。研究区域内的小麦根部重金属含量所占比例较低,这与农作物受土壤源污染的一般研究结果不相符,可能受研究区域大气污染的影响。(3)籽实中的Pb、Cd、Cr、As两两之间有显著的相关性;籽食中的Cr与根、颖壳中的Cr有极显著的相关性;而籽食中的Pb、Cd、As与土壤以及其它器官重金属含量之间没有显著相关性。籽食中的Cu与土壤、根、茎叶、颖壳中Cu含量有显著的相关性;籽食中的Zn与根、茎叶、颖壳中的Zn含量有极显著的相关关系。(4)分别在矿区和矿大校园进行了小麦幼苗种植实验,结果表明,经过Na2-EDTA的处理后种植在矿区的小麦幼苗与种植在矿大校园的样品相比,六种重金属含量都有比较明显的减少;与种植于矿大校园的小麦幼苗样品相比,种植于矿区的小麦幼苗根尖细胞细胞核多泡化严重,核内无序,叶片细胞叶绿体膨胀,结构凌乱,进一步说明小麦污染与区域的大气环境具有较大相关性。
[Abstract]:The heavy metals produced in the production and utilization of coal mines pollute the soil of nearby farmland and result in the pollution of crops through bioenrichment. However, the content of heavy metals in soil is not the only reason for heavy metal pollution in crops. Many studies have shown that heavy metals absorbed by plant leaves from the atmosphere are also one of the causes of crop pollution. Therefore, it is of great significance to find out the source of heavy metal pollution in wheat in Xuzhou northern suburb and to control heavy metal pollution and food safety management. In this paper, the contents of heavy metals in wheat roots, stems, leaves, spikelets and seeds at maturity in the region were measured to evaluate the food safety and health risks of wheat seeds, and the results of correlation analysis were used. The experimental results of wheat seedling response to different environmental factors and the investigation results of pollution sources were used to investigate the sources of heavy metal pollution in wheat seedlings. The conclusions are as follows: (1) compared with agricultural industry standards and food hygiene standards of China, the four heavy metals in wheat seed of 24 sampling sites in the study area were 1.65 times, 0.10 times, 0.60 times and 1.51 times of heavy metals, respectively. The spatial distribution characteristics of the two heavy metals showed that the heavy metal content exceeded the standard was closely related to the distribution of coal mine industry. (2) the single factor pollution index of heavy metals in wheat seed was: 1. PbCrAsCdCuZn. The health risk of heavy metal intake through mouth is as follows: the content of AsPbCuCdZnCr.ZnCU in different organs of mature wheat is the same as that of root seed stem and leaf glume in different organs of mature wheat. For the root glume stem and leaf seed; The content of Cr in different organs of wheat at maturity was the root seed of spikelet stem and leaf in turn. The content of heavy metals in the roots of wheat in the study area is relatively low, which is inconsistent with the general results of crop pollution by soil sources, and may be affected by air pollution in the studied area. (3) there is a significant correlation between the two parts of PbbcdCdCrAs in seeds; There was a significant correlation between Cr in seed food and root and glume, while there was no significant correlation between Pb ~ (2 +) CD ~ (2 +) ~ (2 +) and heavy metal contents in soil and other organs. There was a significant correlation between Cu content in seed food and soil, root, stem, leaf and glume, Zn in seed food and root, stem and leaf. There was a significant correlation between Zn content in glume. (4) Wheat seedling planting experiments were carried out in mining area and mine campus. The results showed that wheat seedlings planted in mining area after Na2-EDTA treatment were compared with those planted in mine campus. Compared with the wheat seedling samples planted in the mine campus, the root tip nuclei of the wheat seedlings planted in the mining areas were more vesicular, the nuclei were disordered, and the chloroplasts of the leaf cells expanded. The disordered structure further indicates that wheat pollution is closely related to the regional atmospheric environment.
【学位授予单位】：中国矿业大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：X56

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