| dc.description.abstract | Although Taiwan has abundant rainfall, however, due to the narrow and densely populated land, steep hillsides, concentrated rainfall, and short rivers, most of the rainwater flows into the ocean quickly, and the fresh water that can be used is insufficient. Compared with the world, Taiwan is a country short of water, in order to obtain more fresh water sources, groundwater has been exploited in many areas, especially in the coastal areas of Yunlin where it is used more frequently. Excessive groundwater extraction leads to problems such as stratum subsidence, seawater intrusion, and groundwater salinization. Therefore, this study selected six drilling wells in the three areas of Taixi, Kouhu and Shuilin, where subsidence is more serious in the Yunlin coastal area of the Zhuoshuixi River Basin. The groundwater aquifer core was taken as the research object, and the groundwater conductivity analysis was simulated by the test results of the core extract to discuss the salinization of the groundwater layer at different sampling points in the Yunlin coastal area.
In the reference literature of this research method, the solid item extraction technology with high efficiency - microwave digestion and extraction method, is used with ion analyzer to detect the salinization index, and the conductivity, chloride ion, bromide ion (chlorine-bromine ratio), sulfate, and nitrite are selected. Nitrate and 6 items of nitrate are used as indicators to measure the degree of salinization of groundwater, and the detection data are simulated through the correction of soil moisture content to simulate the concentration of groundwater. This study focuses on the key ions of seawater intrusion, fish farming, and agricultural pollution, and finds out the causes of soil and groundwater salinization.
The results of the study found that there may be groundwater salinization in Yunlin, Taixi, Kouhu, and Shuilin, and the causes of salinization in each region are different. Taixi is more similar to aquaculture fishery wastewater infiltration and agricultural fertilization. There may be more than three pollution sources causing salinization in the lake area, but it is not obvious from the perspective of the area. The water forest area may be caused by seawater intrusion and agricultural pollution. Two or more pollution sources are found in each area at the same time. It causes salinization, and comparing the correlation coefficients of various ions, it is found that conductivity and chloride ions are highly correlated, which is a key indicator of groundwater salinization. The results of this study are similar to the results of many literatures on groundwater salinization, and the experimental results can be used as a reference for tracking the causes of groundwater salinization and methods for preventing and controlling groundwater pollution. | en_US |