| 摘要: | 在水化學上，除了溫度與壓力外，氧化還原電位(redox potential)與pH是非常重要的基本水質之一。氧化還原電位代表水中及水岩系統(water-rock)中參予氧化還原反應物質的狀態，影響許多元素的存在狀態(species)。雖然台灣的溫泉研究，已超過一百年的歷史，對於各地溫泉(超過100處)的地層、產狀、水溫、水質等，都已有基本認識，但是對於溫泉水的氧化還原電位(redox potential)還是相當缺乏暸解。本研究的主要目的，在於實地量測溫泉源頭之溫泉水的氧化還原電位( ORP : oxidation-reduction potential )，並分析溫泉中常見的氧化還原元素( redox couples)，例如銨離子/硝酸鹽離子，硫酸根/硫化物離子，探討溫泉水中氧化還原主控的成份，以瞭解台灣地區溫泉水的氧化還原狀態，有利於將來更進一步，模擬溫泉泉質的演化、水岩反應，及微量元素(包含重金屬)的沉澱/溶解。本研究採樣的溫泉源頭由北到南有天籟、名流、天祥、未來城、錦屏、虎山、四季、惠來、麒麟峰、泰雅、寶來等共11個溫泉源頭，分屬8個溫泉區，其中5個為自然湧出，6個為鑽井。若以地質分區計，有3個在大屯火山區，3個西部麓山帶，4個在雪山山脈，1個在中央山脈板岩區。研究結果顯示：現地的氧化還原電位(ORP)量測值都小於0mV，顯示溫泉水皆屬於還原狀態。最高值為「天祥」(台北行義路)-23mV ;最低值為「虎山」(苗栗泰安)-277mV。其氧化還原主控離子，主要為硫化物及銨離子。在大屯火山區，因含高濃度的硫化氫(火山氣體主成份之一)，所以屬於主控離子應為硫化物。位於西部麓山帶之未來城、虎山與麒麟峰，其中，未來城的主控離子應為銨離子，虎山則銨離子與硫化物兼具，麒麟峰的主控離子應為硫化物(硫酸根還原作用)。位於雪山山脈的錦屏、四季、惠來及泰雅溫泉，四季、惠來及泰雅都是銨離子主控，錦屏則為硫化物(硫酸根還原作用)。位於中央山脈板岩區的寶來溫泉應是銨離子主控。
Redox potential is one of the most important parameter for water chemistry, represents the interaction of oxidizable and reducible species in water, rock, sediments and biota. The purpose of this study is to explore the redox environment of hot springs in Taiwan by measuring ORP (oxidation-reduction potential) in the field and determines concentrations of commonly found redox couples in hot springs, i.e. NO3-/NH4+, HS-/SO4-2. The results will assist in the physical and chemical interpretation of hot springs, i.e. rock/water interaction and trace element speciation.
A total of 11 hot springs located at 8 areas were surveyed, from north to south are Tien-Lai, Elite, Tian-Hsyang, Future Town, Jin-Ping, Hu-Shan, Four Season, Bali Nature SPA, Kylin Peak, Atayal, and Baolai. The values of ORP measured are all less than 0 mV and suggest the hot springs were reduced. The highest value of ORP is-23 mV in Tian-Hsyang and the lowest value is -277 mV in Hu-Shan. High concentrations of sulfide and ammonium are the dominated redox species in the hot springs.
The hot springs of Tien-Lai, Elite and Tian-Hsyang contain high concentrations of hydrogen sulfide originated form fumarolic gas in the Tatun Volcano Group. In the non-volcanic area, except for the Jin-Ping and Kylin Peak, the other 6 hot springs are ammonium-dominated with h concentrations of 1~55 mg/L. |
