| 摘要: | 氡氣為具放射性之惰性氣體，在自然界中主要來自地殼、土壤和水中鈾系和釷系天然放射性物質，其同位素中以222Rn最重要，其衰變後之子核為金屬，均為具有高LET之α射源，因此，氡氣進入肺部後對組織之傷害甚大。泡湯已是國人常見的休閒活動，而地殼中之鈾系和釷系元素也會進入溫泉水中，並衰變而產生氡氣，但溫泉水中逸出之氡氣可造成其潛在之健康風險。此外，溫泉水中的氡氣亦可應用於探測鈾礦、評估溫泉水之水文狀況(如：流徑、補充量和流速等)、環境污染研究、地震監測等。因此，溫泉水中氡氣活度的量測為重要之研究課題，考量戶外環境量測時之即地性、即時性、連續性、方便性、靈敏度、環境影響程度以及經濟性等因素，本研究擬以矽半導體偵檢器RAD-7探討溫泉水中氡氣量測方法之建立，評估量測系統洩漏率並探討不同水樣品體積、不同溫度及酸鹼值下氡氣自水中的逸出率，以應用於不同環境下實地量測時溫泉水中之氡氣濃度校正。此外，並將上述方法應用於實地量測，探討不同地質區溫泉水中之氡氣濃度之含量。
Radon is a radioactive noble gas produced from naturally occurring radioactive materials of uranium- and thorium-series nuclides in earth crust, soil and waters. Among the radon isotopes, 222Rn is the most important. The harm of radon to lung tissues is considerable due to that the daughters of radon are metallic and high LET (linear energy transfer) emitters. Hot spring bath has been a common activity for the public in Taiwan, and the radon emanated from uranium- and thorium-series nuclides dissolved in hot spring water could potentially cause health risk. In addition, radon in hot spring water can be applied to explore uranium, monitor hydrologic conditions (e.g., flow path, recharge volume and flow rate), investigate environmental pollution and observe earthquake. Accordingly, the measurement of radon in hot spring water is a significant issue. In this research, considering the requirement of in-situ, real-time and continuous measurement as well as the convenience, sensitivity, economy and the influence of environment, we plan to establish a method for determining radon concentration in hot spring water for the RAD-7, a silicon semiconductor detector. For this method, the leakage of radon in the measuring system and the emanation rate of radon from hot spring water with different sample volume, temperature and pH will be evaluated to calibrate radon concentration determined by the instrument. Besides, the method will be further applied to in-situ measurement to investigate the concentration of radon in hot spring water from different geological areas. |
