Geochemical characteristics of porewater and sediments from Kang-wei and Sin-wen, southwestern Taiwan
| Autor: | Lee chih-wei, 李志威 |
|---|---|
| Rok vydání: | 2000 |
| Druh dokumentu: | 學位論文 ; thesis |
| Popis: | 88 The southwestern coastal plain area of Taiwan was well known for its high concentrations of arsenic and humic substances in deep groundwater. In order to explain the origin of arsenic and humic substances, cations and total organic carbon (TOC) of sediments, and cations, anions and fluorescence intensity of porewater of drilling cores from Sin-wen and Kang-wei were analyzed. The sediments underneath Kang-wei at depth less than 120 meters were deposited in marine environment during the Holocene transgression period. Between 60 and 120 meter depths, TOC contents are higher than the upper layers. The good correlation among TOC concentrations, arsenic, iron and manganese contents of sediments suggests that they may have the same enrich-ment processes. All sediments with the highest arsenic concentrations from Zei-kang, Sin-wen and Kang-wei, respectively, occur at the horizon deposited in the marine (lagoon) environment during the Holocene transgression. It is proposed that the strongly anoxic environment shown by the deeper part of the sediment column underneath the coastal area of southwestern Taiwan was induced by oxygen-consuming organic matters. The high concentrations of groundwater might be attributed to the reduction of iron oxides and the mineralization of organic matters. |
| Databáze: | Networked Digital Library of Theses & Dissertations |
| Externí odkaz: |
|