| Summary: | 碩士 === 輔英科技大學 === 環境工程與科學系碩士班 === 99 === Due to the development of industry, livestock and urban, however, the Gaoping river and nearby ecosystem have been severely polluted by wastes discharged from factories and house sewage in the vicinity, resulting in a decline in productivity. When various anthropogenic heavy metals enter the estuary, the mangrove ecosystem is a major reservoir of heavy metals pool. The purpose of this study was to understand the behavior of heavy metals in the Gaoping Estuary mangrove ecosystem. Bioavailability and concentration of heavy metals in sediment and mangrove plants (Phragmites communis and Avicennia marina and Ipomoea pes-caprae) were investigated.
Results show that the concentrations of Zn and Ni (average concentration: Zn 72.65 mg/kg, Cu 3.31 mg/kg) were higher in Phragmites communis, Cu, Pb and Ca (average concentration: Cu 31.31 mg/kg, Pb 3.12 mg/kg, Ca 416.84 mg/kg) in Avicennia marina, Cd, Cr, Al and Fe (average concentration: Cd 3.33 mg/kg, Cr 3.99 mg/kg, Al 5.05 mg/kg, Fe 21.12 mg/kg) in Ipomoea pes-caprae. Sediments from mangrove area contained lower bioavailable concentration of Zn, Cu, Ni, Cr and Pb, and higher less-availible concentration of Zn, Ni, Fe, Al than those non-mangrove area. The results reveal that metal bioavailability of mangrove sediment may decrease due to the uptake by mangrove plants. The Zn, Ni, Cr concentrations of Phragmites communis and Zn concentration of Avicennia marina positively correlated with the bioavailable concentrations of mangrove sediment. Mangroves bioconcentration factors (BCFs) for Zn, Cu were higher than other metals. The Zn, Cd and Cr BCFs of Phragmites communis,
Cu BCF of Avicennia marina, and Cd, Cr BCFs of Ipomoea pes-caprae were higher than other metals.
For phytoremediation initiatives, mangrove ecosystems are more appropriate candidates for phytostabilisation retaining metal inputs and thereby reducing transport to near estuarine and marine system.
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