相山铀矿区稻米放射性核素铀含量研究

发布时间：2018-03-03 06:41

本文选题：稻米　切入点：铀含量　出处：《东华理工大学》2017年硕士论文　论文类型：学位论文

【摘要】：相山铀矿区是我国迄今为止发现的最大规模火山岩型铀矿床,已有超过半个世纪铀矿石开采和选冶历史。铀矿区内有近10万人居住,除少量铀矿生产工作人员外,主要为农民,矿区主要农作物为水稻,水稻可以一年两熟。铀矿开采过程产生的大量尾矿和含矿废水没有得到有效处置,对矿区环境造成了较为严重的放射性铀污染。多年来的调查工作主要集中于地质成矿研究,极少量针对铀矿区开展放射性环境专项调查。相山铀矿区稻米放射性核素铀含量的研究报道较少。本研究重点对铀矿区稻米放射性核素铀进行调查,分析相山铀矿区稻米放射性核素铀含量及分布特征;探讨各亚区稻米铀含量成因分析,水稻土铀含量与稻米铀含量的关系;并利用单因子污染指数法对相山铀矿区稻米放射性核素铀污染进行全面评价;开展了稻米铀元素健康风险评价,对加强研究区粮食质量安全和保护公民身体健康具有重要意义,也为整个矿区环境治理工作提供基础数据参考。主要研究成果如下:(1)相山铀矿区129件样品稻米放射性核素铀含量平均值为1.39 ng·g-1,是含矿未采区稻米铀含量平均值的1.19倍,有51.16%的样品超标,已对矿区粮食安全构成威胁;正在采矿区和水冶厂区稻米铀含量平均值分别为1.69 ng·g-1和1.39 ng·g-1,分别是含矿未采区稻米铀含量平均值的1.44倍和.1.19倍,样品超标率分别为68.89%和50%,表明相山铀矿区稻米放射性核素铀含量超标样点主要集中于这两个亚区。4个亚区稻米铀含量平均值高低顺序为:正在采矿区(1.69 ng·g-1)水冶厂区(1.39 ng·g-1)含矿未采区(1.17 ng·g-1)废弃矿井区(0.96 ng·g-1)。(2)水稻土铀含量呈现出表层至底层降低的规律,铀元素主要集中在水稻土表层,且主要受到外源影响,与水稻土下伏基岩铀含量关系不大。铀元素迁移富集的途径为“铀矿开采(铀矿尾矿渣)→地表水→水稻土”,从而造成了稻米铀元素含量特征。研究区水稻土铀含量与稻米铀含量关系复杂,受到矿石运输条件、露天尾矿堆放、水冶厂排水管道等因素的综合影响。正在采矿区水稻土铀含量与稻米铀含量可以构建拟合度较高的指数函数回归方程,稻米铀含量随水稻土铀含量的增加而增加。(3)整个研究区稻米样品单因子污染指数平均值为2.31,达到中度污染水平;未受污染、轻度污染、中度污染、重度污染的稻米样点分别占样品总数的14.73%、35.66%、27.90%和21.71%。4个亚区及对照区稻米铀污染单因子指数平均值高低顺序为:正在采矿区水冶厂区含矿未采区废弃矿井区对照区。正在采矿区和水冶厂区稻米单因子污染指数平均值均达到中度污染水平;含矿未采区和废弃矿井区稻米单因子污染指数平均值均达到轻度污染水平;对照区未污染。(4)计算提出江西省大米铀元素对成人和儿童健康风险的致癌风险斜率系数分别为1.04×103(d·kg)·mg-1,3.98×102(d·kg)·mg-1。各亚区成人和儿童食用稻米的CRi指数高低顺序均为:开采矿井区水冶厂区含矿未采区废弃矿井区对照区。评价表明研究区成人和儿童食用正在采矿区和水冶厂区的稻米具有一定的致癌风险,而食用含矿未采区、废弃矿井区及对照区的稻米均不存在致癌风险。
[Abstract]:The Xiangshan uranium mining area is the largest volcano rock type uranium deposits found so far in China, there are more than half a century of uranium ore mining and smelting history. Uranium mining area of nearly 100 thousand people, in addition to a small amount of uranium production personnel work, mainly for farmers, the main crops for mining of rice, rice can be two a year well. A large amount of tailings produced process of uranium mining and ore bearing wastewater has not been effective disposal, caused serious pollution to the environment. The radioactive uranium mine survey work over the years mainly focused on geological research, very little to carry out radioactive uranium mine environment special investigation. Xiangshan uranium deposit area rice radionuclide uranium content research report less. This research focuses on the uranium mine rice radionuclide uranium investigation, analysis of radionuclide uranium content and distribution characteristics of rice in Xiangshan uranium mining area; to explore the sub regions of rice Analysis of causes of uranium content, relationship between paddy soil and rice of uranium content in uranium content; and to conduct a comprehensive evaluation of the Xiangshan uranium mine rice radioactive uranium pollution by using the method of single factor pollution index; carry out rice uranium health risk assessment, has important significance to strengthen the research area of food quality and safety and protect the health of citizens, also provide the basis for the reference data for the entire mine environment. The main research results are as follows: (1) the Xiangshan uranium mine in 129 samples of rice radionuclide uranium content was 1.39 ng - g-1, is 1.19 times the ore is the average uranium content of rice, 51.16% of the samples exceed the standard, is a threat to food security in mining area; in the mining area and the average content of uranium hydrometallurgy of rice were 1.69 ng g-1 and 1.39 ng g-1, which is 1.44 times of ore is the average uranium content of rice and.1.19 times, super sample Standard rates were 68.89% and 50%, showed that the Xiangshan uranium deposit area rice radionuclide uranium content exceed the standard sample mainly concentrated in the two sub region.4 sub regions, the average content of rice uranium mining area is level of order: (1.69 ng g-1) hydrometallurgy plant (1.39 ng g-1) ore unmined area (1.17 ng g-1 (0.96 ng) of abandoned mine area g-1). (2) showed uranium content in rice soil surface layer to the bottom layer decreases, the uranium is mainly concentrated in the top soil, and mainly affected by exogenous effects, and paddy soil under the relationship of bedrock uranium content. Uranium enrichment for the migration pathway "uranium mining (uranium tailings), surface water, paddy soil, resulting in the characteristics of uranium content in rice paddy soil. Research on the relationship between the uranium content and the content of uranium ore by rice complex, transport conditions, open tailings pile, comprehensive effect of mills and other factors. It drains Exponential regression equation in Paddy Soils in uranium mining area and rice uranium content can build a high fitting degree, increase the uranium content in rice paddy soil with uranium content increased. (3) the study area of rice samples of single factor pollution index reached an average of 2.31, moderate pollution level; without pollution, light pollution, moderate pollution, severe pollution of rice samples accounted for 14.73% of the total samples, 35.66%, 27.90% and 21.71%.4 sub area and the control area of rice uranium single factor pollution index average level of order: mining area ore hydrometallurgy plant is unmining area of abandoned mine area. The mining area and control area is the single rice mill the average pollution index reached the moderate level of pollution; ore mining and abandoned mine area of rice is not the single factor pollution index average value reached the level of light pollution; control area without pollution. (4) proposed in Jiangxi Province Rice uranium for adults and children health risk of cancer risk slope coefficients were 1.04 x 103 (D - kg) mg-1,3.98 * 102 (D - kg) CRi index, the order of adults and children mg-1. sub regions of rice are: the mining area of uranium ore mining plant not abandoned mine wells the control area. The evaluation indicates that the adults and children in study area are edible rice plant and suiyeh mining area has a certain risk of cancer, but not edible ore mining area, abandoned mine area and the control area of the rice does not have the risk of cancer.

【学位授予单位】：东华理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：X591;X75

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