重金属汞在组合式人工湿地系统中的迁移转化规律研究

发布时间：2018-04-25 13:07

本文选题：人工湿地 + 重金属汞　；参考：《中国矿业大学》2017年硕士论文

【摘要】：薛城小沙河是中国南水北调东线工程重要的输水通道及调蓄湖泊,为了提高小沙河水质,流域进行了大规模的湿地修复工程。为了解人工湿地系统中重金属汞的迁移转化规律,本研究以薛城组合人工湿地系统为研究对象,于2016年5月及9月测试了沉积物、水体和植物中汞的含量及形态,探讨重金属汞在组合式人工湿地系统中的迁移转化特征。沉积物中总汞及三种形态汞(可移动汞、半移动汞、不移动汞)的含量分析结果表明,半移动汞为主要赋存形式,占比为34.12%~85.24%;pH和有机质含量对汞的形态转化有显著影响。柱状沉积物中总汞含量在5月、9月分别表现为中部富集型、上部富集型,三种形态汞与其基本性质之间无明显相关关系,总体上说明柱状沉积物中各个形态汞的含量分布不受其基本性质的影响。薛城人工湿地水体5月总汞浓度变化范围4.96 ng/L~103.16 ng/L,9月水体各采样点间总汞浓度范围为2.52 ng/L~81.26ng/L,水体中总汞含量沿程呈现递减趋势,总汞以颗粒态汞为主,占比为60.67~68.49%,溶解态汞和活性汞占比较低。通过计算得到5月和9月间隙水溶解态汞向上覆水体扩散通量分别为76.63ng·(m2·d)-1和55.17 ng·(m2·d)-1。湿地植物对汞的富集能力具有明显的时间、种间和器官差异。同种植物在9月的富集能力均大于5月的富集能力。5月湿地植物对汞的富集能力表现为:黄花鸢尾香蒲水葱千屈菜再力花,9月表现为:再力花黄花鸢尾千屈菜香蒲水葱。5月时五种植物对总汞运输能力均较弱,(TF1),富集特征表现为根部囤积型,9月表现为富集型植物。同种植物不同部位对汞的富集能力有差异,5月份表现为根叶茎,9月份表现为叶根茎。分析5月及9月植物各器官汞含量与沉积物总汞及各种形态汞的相关性,发现沉积物中的汞并不是影响植物汞含量的主要因素。
[Abstract]:Xue Cheng Xiaosha River is an important water conveyance channel and storage lake in the East Route of South-to-North Water transfer Project in China. In order to improve the water quality of Xiaosha River, a large-scale wetland restoration project has been carried out in the basin. In order to understand the migration and transformation of heavy metal mercury in constructed wetland system, the contents and forms of mercury in sediments, water bodies and plants were measured in May and September 2016 with Xue Cheng combination constructed wetland system as the research object. The characteristics of migration and transformation of heavy metal mercury in combined constructed wetland system were discussed. The results of analysis of total mercury and three forms of mercury (movable mercury, semi-mobile mercury, non-mobile mercury) in sediments showed that semi-mobile mercury was the main form of occurrence, accounting for 34.12% and 85.24% of pH and organic matter content had a significant effect on the morphological transformation of mercury. In May and September, the total mercury content in columnar sediments showed a central enrichment type and a upper enrichment type, and there was no significant correlation between the three forms of mercury and their basic properties. It shows that the distribution of mercury in columnar sediments is not affected by its basic properties. The variation range of total mercury concentration in Xuecheng constructed wetland in May was 4.96 ng/L~103.16 / L, and that in September was 2.52 ng / L ~ 81.26 ng / L among sampling points. The total mercury content in the water decreased along the course, and the main mercury was granular mercury. The proportion of dissolved mercury and active mercury is 60.67 and 68.49 respectively. The diffusion fluxes of dissolved mercury from interstitial water to the overlying water in May and September were calculated to be 76.63ng / m ~ (2) D ~ (-1) and 55.17 ng / m ~ (2) m ~ (2) D ~ (-1), respectively. There were significant time, interspecific and organ differences in mercury enrichment of wetland plants. The enrichment ability of the same plant in September was higher than that in May. In May, the total mercury transport capacity of five plants was weaker than that of TF1, and the enrichment characteristics were root accumulation type and September accumulation type. The accumulation ability of mercury in different parts of the same plant was different. In May, the root, leaf, stem and stem appeared as leaf and rhizome in September. The correlation between mercury content in plant organs and total mercury and various forms of mercury in sediments in May and September was analyzed. It was found that mercury in sediments was not the main factor affecting mercury content in plants.
【学位授予单位】：中国矿业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：X703

【参考文献】