利用離子交換樹脂結合X射線螢光分析儀 應用於污染源偵測

Abstract

隨著工業的發展與進步，許多環境問題也隨之出現。其中工業廢水未經適當處理而不當排放至環境中，水中的重金屬將造成人體以及生態的危害。由於工業廢水常常為短時間的大量、隱密且廣布於大規模的區域排放，對於監測污染源帶來更多的挑戰。上述的工業廢水排放之特性凸顯出一個高效且簡單的方法來快速判別污染源的重要性與急迫性。但是傳統應用於監測廢水排放的方法十分複雜、且相對昂貴並耗時，因此本研究旨在利用一種創新的重金屬監測為利用裝填離子交換樹脂的小袋結合X射線螢光核心掃描儀 (Itrax XRF-CS)在多變的環境當中有效識別可疑的污染源，利用快速篩檢的概念在大範圍區域中找出可能的污染排放點，並可以讓後續的化學分析來進一步的介入調查小區域的污染。 研究區域位於台灣東北角的半屏溪，此溪受到酸性礦水的影響，我們進行兩次為期四周的採樣。結果表明，離子交換樹脂結合Itrax XRF-CS可用於長期監測金屬濃度小於1 mg/L之低污染環境與找出可疑污染源。其中，鄰近酸礦排水的區域可檢測到Zn、Ni、Mn、Fe、Cu和Sr的濃度明顯升高，Itrax計數比未污染地區高1.8至3528倍。其中Zn在污染區與非污染區表現出最大的濃度差異，為3528倍。其餘Ni、Mn、Fe、Cu 和 Sr 的Itrax計數分別比非污染區域高 1.8、29.2、46.1、2.4和 5.9倍。此外，結果表明沉澱的強度會影響樹脂吸附的金屬量。當降水量達到每週14至24毫米時，河川中的金屬濃度達到峰值。然而隨著每週降水量的增加，卻導致水中金屬濃度下降。這指出河水中的濃度由稀釋和淋溶作用的平衡決定，使降雨量中等的幾週出現最高金屬濃度。 此研究可得知離子交換樹脂具有良好的重金屬吸附性能，作為一種靈敏工具，可應用於各種污染程度的污染監測。離子交換樹脂袋與Itrax XRF-CS互相搭配是快速監測大面積潛在污染水系統的有效的方法。

With the rapid industrial development, numerous environmental issues have emerged. Improper industrial wastewater discharge into the environment has led to heavy metal release, posing risks to human health and ecological systems. Moreover, the large, sporadic, and often covert industrial wastewater discharges make it challenging to monitor and identify pollution sources. This highlights the importance of developing an efficient and simple method for screening pollution sources of industrial wastewater. However, conventional monitoring methods for heavy metals are still complicated, relatively expensive, and time-consuming. Therefore, this research aims to evaluate an innovative heavy-metal monitoring technique that combines ion-exchange resin sachets with Itrax X-ray fluorescence core scanner (XRF-CS) to identify suspected pollution sources efficiently under highly variable natural conditions. This methodology operates like a rapid test, enabling the swift detection and localization of potential pollution sources across extensive areas. Subsequently, the findings from this rapid screening process guide and inform further chemical analyses. Which can be conducted in specific small areas, optimizing resource utilization and minimizing time and cost expenditures. The resin sachets, which have a large capacity to take up heavy metals quickly, were deployed weekly during two four-week sampling sessions in the Bangping River in northeastern Taiwan. The study area still experiences the influence of acid mine drainage following the closure of a coal mine. The captured heavy metals in the resin sachets were analyzed using the non-destructive, fast, and cost-efficient Itrax XRF core scanner. The results suggest that combining ion-exchange resins with Itrax XRF-CS is useful as long-term monitors of heavy metals in a low pollution-level setting (metal concentration <1 mg/L), and this approach allows us to pinpoint pollution sources along the studied river. Especially, Zn, Ni, Mn, Fe, Cu, and Sr could be detected near the acid mine drainage, where Itrax counts were 1.8 to 3430.6 times higher than in unpolluted areas. Zn shows the largest difference between polluted and non-polluted areas, with the Itrax counts of the samples in polluted areas 3528 times higher than their non-polluted counterparts. Ni, Mn, Fe, Cu, and Sr’s Itrax counts were 1.8, 29.2, 46.1, 2.4, and 5.9 times higher, respectively than the corresponding counts measured in non-polluted areas. In addition, our results demonstrate that the intensity of precipitation influences the amount of metal adsorbed by the resins. As the precipitation reached 24 mm, the metal concentrations reached a peak value. However, as the precipitation continued rising beyond this point, the metal concentrations started to decrease again. There appears to be a balance between dilution and wash-in processes, contributing to the highest concentrations of metals occurring at intermediate precipitation levels. In summary, ion exchange resins are a sensitive tool that can be applied in pollution monitoring at various pollution levels due to their high performance in adsorbing heavy metals. Consequently, ion-exchange resin sachets combined with XRF core scanner analysis is a cost-effective way to quickly monitor large areas of potentially polluted aquatic systems.