應用多變量統計方法探討區域地下水之水質特徵

Abstract

地下水為一重要水資源，由於地下水水質受到氣候、含水層特性及其與岩石間之交互作用等諸多因素影響，因此，了解地下水特徵，對於有效管理地下水資源乃十分重要的。為了識別區域地下水水質特徵，本研究應用因子分析法、群集分析法及派博水質圖法評估台北盆地、蘭陽平原、濁水溪沖積扇、嘉南平原、屏東平原與金門地區之地下水水質特徵。 分析結果顯示，所有研究區域之第一因子皆與鹽化有關，尤其在濁水溪沖積扇、嘉南平原及屏東平原之沿海地區乃鹽化狀況較嚴重區域。而於蘭陽平原扇尾區、濁水溪沖積扇之西南地區，以及嘉南平原之砷污染狀況較顯著，由於砷乃引起烏腳病及致癌等健康風險主因之一，因此，上述提及之地下水區其地下水並不適合飲用。大金門地區地下水多傾向氧化狀態，反之，臺灣地區地下水多傾向還原狀態。整體而言，台北盆地、蘭陽平原扇頂區及金門地區其地下水水質較佳。本研究結果可提供此六個研究區域永續利用其地下水資源及劃定地下水保護區之參考。

Groundwater is an important water resource. The quality of groundwater is influenced by many factors, including climate, aquifer properties, and water-rock interactions etc. Understanding the groundwater characteristics is crucial for effective management of groundwater resources. In order to identify the characteristics of regional groundwater quality , the study applied factor analysis, cluster analysis and Piper diagram to evaluate the characteristics of groundwater quality in Taipei basin, Lanyang plain, Choushui River alluvial fan, Chianan plain, Pingtung plain and Kinmen. The analyzed results show that the first factor in all study areas correlates to salinization, especially the coastal areas of Choushui River alluvial fan, Chianan plain and Pingtung plain which are suffered serious salinization. Arsenic pollutant is notable in the distal-fan area of Lanyang plain, southwestern Choushui River alluvial fan and Chianan plain. Since arsenic is one of the major health risk factors for blackfoot disease and cancer, the groundwater of the above-mentioned areas is not suitable to drink. Groundwater in the most region of large Kinmen island tends to be in oxidizing conditions. Whereas groundwater in most region of Taiwan tends to be in reducing conditions. As a whole, the groundwater quality is good in Taipei basin, proximal-fan Lanyang plain and Kinmen. The results of the study may provide references for sustainable utilization of groundwater resources and the delineation of groundwater protection zones of the six study areas.