| 英文摘要 |
The goal of this project is to continue Environmental Protection Administration, Executive Yuan, R.O.C. (Taiwan)(EPA) natural causes arsenic-rich research project results, combine the Chiayi county calendar year arsenic-rich potential survey data, and focus on the uninvestigated area, that using the area with water after soil survey operating as the core concept. That to update and modify the distribution map of arsenic-rich probability of soil and groundwater in Chiayi County, be helpful to grasp the high-risk areas with an excessive arsenic concentration in soil or groundwater and provide relevant information, administrative management strategies and countermeasures, also applies them to the future spatial development location planning of Chiayi County land plan.
The overall project content can be divided into 4 major projects:1.Survey on the distribution and application of groundwater wells. 2.Groundwater and soil sampling analysis. 3.Detection of arsenic content in crops. 4.Results evaluation and geographic statistics.
According to the groundwater wells survey results of the distribution and utilization in this project, the civilian wells in Chiayi County are mostly distributed in towns such as Puzi City, Xingang Township, Shuishang Township, and Xikou Township, etc. And they are mostly privately drilled by the public. In addition, this project investigates the farmland that exceeds the control standards and the EPA regularly monitors the farmland over the years, which calculates its judgment score according to the "Agricultural Soil Arsenic Pollution Judgment and Treatment Principles".The calculation result shows that the judgment results of 13 mounds are all caused by irrigation of natural arsenic-rich groundwater.
Regarding the farmland surveys, the soil heavy metals were investigated in the near, medium, and far areas according to the irrigation wells. The heavy metal analysis results showed that only the arsenic concentration in the eight heavy metal analyses exceeded the monitoring standards or control standards for edible crop farmland, and the contents of other heavy metals all met the regulatory standards. In addition, the results of soil XRF analysis and Kriging statistics show that the distribution of arsenic concentration in the surface soil (0-15 cm) and the distance from the civilian well show a decline, while the other heavy metals show no significant decline. From this, it could be concluded that the source of soil arsenic accumulation should be caused by the irrigation of groundwater in civilian wells.
Regarding the determination of the cause of arsenic-rich, the result of the determination showed that the 10 farmlands selected in this project could be determined as the arsenic concentration in soil caused by natural arsenic-rich groundwater. Therefore, it is recommended to notify the relevant agricultural, water conservancy, and health authorities of the analysis result in the farmland exceed the control standards in accordance with the provisions of the Soil and Groundwater Pollution Remediation Act, and to hold a consultative meeting to handle relevant matters. In addition, the frequency of regular monitoring can be developed for farmland exceeding the monitoring standard based on the evaluation of the early warning period of the EPA. In the crop analysis part, the data has been provided for reference by relevant agricultural units.
Finally, the updated arsenic-rich probability distribution map of groundwater from this project shows that the boundary of the groundwater potential zone in Chiayi County is the area east of the Tainan period transgressive coastline on the east side of Chiayi County, which has low arsenic-rich potential, while the high arsenic-rich potential zone is distributed in Xikou Township, Liujiao Township, Xingang Township, Shuishang Township, Puzi City and Yizhu Township, and then compared with the " Platform for querying potential Range of Arsenic concentration in groundwater of Environmental Protection Administration, Executive Yuan" for arsenic-rich areas. , there are still 24 villages in Chiayi County that have not been included in the potential map. Therefore, this project will provide the planned survey data to the EPA as the updated information of the potential map. In addition, although the current national land plan has delineated the distribution area for the future agricultural development space and the classification of agricultural land, this project still uses the geographic information system to overlay the updated groundwater arsenic-rich probability distribution map of Chiayi County. For towns that are planned to be rice production areas such as Dalin Township, Xikou Township, Xingang Township, and Minxiong Township, etc, mark areas with high arsenic-rich potential, suggest priority implementation of arsenic-rich management and monitoring countermeasures, and provide authority and responsibility units as a reference.
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