Applying the Chelex-100 to Measure Trace Metals in High Salinity Samples in Southern Jhuoshuei River Alluvial Fan in Central Taiwan

Due to the steep terrain and seasonal precipitation, retaining water on the surface in Taiwan is challenging. As a result, groundwater resources play a significant role in most types of water usage. However, historical data suggest that groundwater in the shallow layers near the coastal region of the South Jhuoshuei River Alluvial Fan has become widely salinized. This study collected multiple batches of water samples to analyze their characteristics and seasonal variations. The results indicate that the degree of salinization in the shallow layer is higher than in the deep layer. However, the data from the water samples only suggest that salinity is contributed to by saline water, without clarifying whether the source is lateral intrusion or surface contamination. To better understand salinity in this region, this study used Chelex-100 chromatography to reduce salinity and concentrate trace metals in the samples. The concentration of trace elements differs significantly between seawater, which has low levels, and fish farms, which exhibit higher levels. This distinction helps identify the source of the saline water. Initial tests showed that wells near Taixi had higher concentrations of trace elements, particularly Pb. In contrast, wells near Yiwu and Qiongpu displayed lower concentrations of trace elements. These findings suggest that salinization in the Taixi region is likely caused by anthropogenic sources, while salinization near Yiwu and Qiongpu results from lateral intrusion.