| Summary: | 碩士 === 國立高雄海洋科技大學 === 海洋環境工程研究所 === 106 === Mercury (Hg) is probably one of the most hazardous pollutants of aquatic environments in both organic and inorganic forms. Most of the anthropogenic Hg enters the aquatic system is in an inorganic form, which will be in situ converted to an organic form as methylmercury (MeHg) by aerobic and anaerobic bacterial activity. Mercury accumulated in sediments would enter the food chain by benthic biota consumption. The objectives of this study were to investigate the distribution and pollution levels of Hg and MeHg in the sediments of Kaohsiung Harbor; by which the degree of Hg enrichment, accumulation and potential ecological risk were evaluated. The pollution status of Hg was tully studied for references of a future management and pollution remediation strategies. The sediment samples were collected from Kaohsiung Harbor including a total number of n=120 sites for estimation of average methyl-Hg concentration. Sediments was samples over a period of 1 year, from July 2016 to october 2017. Quantified MeHg in sediment samples were performed using gas chromatography mass spectrometry (GC-MS) after ethyl derivatization. Current research results indicate that the average concentrations of total mercury in the sediments from Export I (EI), North channel (NC), Love river (LR), Canon River (CR), Jen-Gen River (JR), Salt River (SR), South channel (SC), Export II (EII) in Kaohsiung Harbor Area are 579±300、847±480、2,208±655、5,108±3170、877±240、577±151、570±231 and 455±193 μg/kg. Mercury EF at each station is between 0.7–6.1. consequently, Hg of sediments in Kaohsiung Harbor is mainly contributed by human activities (EF>1). The classification based on the EF values indicated that the contamination in Canon River (EF=6.1) was to the moderately severe (EF=5-10). The Hg concentration of sediments in the north channel and the estuaries of Love River, Canon River, and Jen-Gen River was higher than the median effect range (ERM 710 μg/kg), indicating that Hg was relatively high hazardous to benthic organisms. For the remaining stations, Hg concentration of sediments was in the range of ERL(effect range low, 15 μg/kg) and ERM, showing a relatively lower risk to benthic organisms. The mean concentrations of methylmercury in the sediment sampled from the EI, NC, LR, CR, JR, SR, SC and EII sediments were 0.7±1.4、7.2±10.7、10.4±17.0、37.4±58.5、5.0±6.7、2.4±4.1、4.3±8.2 and 4.3±7.1 μg/kg, respectively. sediments in the estuary of Canon River has a higher MeHg of 37.4 μg/kg dw than that in Love River, 10.4 μg/kg dw. The relatively high concentrations of T-Hg and MeHg were found in the river estuary of Kaohsiung Harbor. The results suggests that Hg in the study area likely originated from the catchments of river. MeHg made up 0.01 to 1.50% of the sediment's T-Hg. There is positive correlation between MeHg, T-Hg and total organic carbon (TOC) concentrations, and negative correlation was observed between pH values with MeHg concentrations in the sediment in the study area. These results suggested the distribution of MeHg is mainly influenced by the sediments characteristics and environment conditions.
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