碩士 / 國立臺灣大學 / 海洋研究所 / 98 / The distribution, partitioning and fluxes of Mercury (Hg) with its controlling factors had been investigated in surface waters of the Danshuei River estuary and nearby coastal areas of Taiwan in summer (May 2003 and July 2004) and winter (December 2008 and January 2010). Additionally, in January 2010 the Hg in different size phases of physical separation in the Danshuei River was analyzed such as filter-passing total dissolved (HgD≤ 0.45μm, ≤ 0.45 μm), truly dissolved (HgD ≤ 1kDa, ≤ 1 kDa), colloidal (HgLC, 1 kDa ~ 0.1 μm & HgHC, 0.1 μm ~ 0.45μm) and particulate (HgP, ≥ 0.45 μm) Hg. The distribution and concentration of Hg species varied spatially and temporally. Total Hg (∑Hg) concentration in summer overall ranged from 1.7 to 34.3ng/L and ∑Hg from 1.0 to 5.1 ng/L; in winter concentrations of ∑Hg and HgD≤ 0.45μm ranged from 1.8 to 40.9 and 0.6 to 29.8 ng/L, respectively. HgD≤ 0.45μm and dissolved organic carbon significantly correlated each other (R = 0.94), and a good correlation between HgP and particulate organic carbon (mg/g) was observed also (R= 0.66). These indicate that organic matter has a significant influence on the concentration distribution of the Hg in the Danshuei River estuary. Moreover, there was a significant Hg removal as a non-conservative mixing pattern at a low-salinity upper estuary（salinity 0~10）, in which a strong redox condition took place. Therefore, the Hg distribution was significantly affected by the organic matter and redox changes in Danshuei River estuary. Higher particle-water partition coefficients (log Kd = 5.4± 0.5, n = 43) were observed between particulate and dissolved Hg, and significantly affected by TSM concentration (total suspended matter) and DO (dissolved oxygen level). Through analyzing dissolved Hg in different size fractions, the Hg in the upstream of the Keelung River and Hsing-Dian Steam was mainly in the truly dissolved form and in the upstream of the Dai-Han Steam largely the colloidal in macro-molecule weight. Most of the riverine dissolved Hg were turned into particulate through colloidal pumping processes and then removed in the upper Danshuei River estuary at Taipei metropolitan areas, in which the hypoxia took place as a result of high human-derived pollutions. To estimate the first-order Hg budget within the estuary, ca. 83% ~ 91% (n=4)of the Hg removal rates were found by using mixing patterns of Hg versus salinity. The estuarine removal flux (about 22 g/day/m2) in summer was approximately two times of that in winter (about 10 g/day/m2).
Keywords: Hg, speciation, spatial distribution, Danshuei River esturary, flux
| Identifer | oai:union.ndltd.org:TW/098NTU05279025 |
| Date | January 2010 |
| Creators | Shih-Chao Yeh, 葉士肇 |
| Contributors | Chun-Mao Tseng, 曾鈞懋 |
| Source Sets | National Digital Library of Theses and Dissertations in Taiwan |
| Language | zh-TW |
| Detected Language | English |
| Type | 學位論文 ; thesis |
| Format | 58 |
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