台灣西北部桃園觀新藻礁與北海岸藻礁重金屬含量分析

Heavy Metal Contents in Algal Reef Coasts in Taoyuan Guansin of Northwest Taiwan and North Coast of Taiwan

為瞭解台灣西北部海岸桃園觀音、新屋藻礁污染情形，確認污染物的來源位置及擴散方向，針對桃園市觀音區及新屋區藻礁海岸，共10條樣線設置28處採樣站，對照組設置於台灣新北市石門區及三芝區藻礁海岸，設置8處採樣站。分別於西北部桃園海岸取得84樣本，以及北海岸取得24樣本，各樣本以X-射線螢光光譜儀進行32種重金屬濃度分析，採用多變數分析以定量數據來計算樣本之差異，依據主成分分析之分布序列圖及群團分析樹狀圖的結果，釐清各元素之關連性後，針對特定元素討論重金屬濃度在空間分布現象。鈦、鋯、釷、鐵、釩雖濃度不同但樣本間的變化趨勢有高度相似，鈣、鍶、鈧是另一群高度相似性的元素，此外，鋇、銫、碲、銻、錫含量雖不豐富，但有些屬放射性同位素，在樣本間的變化相似，顯示樣本間元素來源可能一致，應列入監測。桃園觀新藻礁的鋯濃度高達4,462 ppm，平均值747 ppm，對照北海岸的藻礁樣本最大值181 ppm，平均值僅78 ppm，特別是觀音近岸區鋯濃度明顯較高的趨勢，至離岸250 m處仍有約1,800 ppm的高值，顯示鋯的來源以陸地為主；觀新藻礁鈦濃度高達5,735 ppm，對照北海岸的樣本最大值1,883ppm；觀新藻礁鍶濃度高達4,622 ppm，對照北海岸的樣本最大值1,808 ppm。觀新藻礁鍶、鈦、鋯含量對照北海岸的樣本差異實在太大，確實有外來的污染。推論人工蛇籠護岸堤內填土方及小飯壢溪、新屋溪、後湖溪、社子溪皆有污染物匯入，而堆置於新屋區永安漁港南側海岸的石門水庫淤泥，可能也有污染物，應針對可能之來源加強查核。

This study was conducted to investigate heavy metal contents in Guan-sin algal reefs coast of Taoyuan, northwest Taiwan, in order to confirm the location and direction of pollution sources. Twenty-eight stations were set up in ten sampling lines in Guanyin District and Sinwu District, Taoyuan City. Eight sampling stations were set up as controls in Shimen District and Sanzhi District, New Taipei City, north Taiwan. In total 84 samples were obtained from the studied northwest region and 24 from the north coast region. Every sample was measured by X-ray fluorescence for 32 heavy metal contents. Multivariate statistical analysis, Ordination of principal component analysis and dendrogram of cluster analysis were used for the quantitative analysis. This has confirmed several main elements for discussion. Concentrations of Titanium (Ti), zirconium (Zr), thorium (Th), iron (Fe), vanadium (V) were different, but trends of change between samples were highly similar. Calcium (Ca), strontium (Sr), scandium (Sc) were another group of highly similar elements. In addition, barium (Ba), cerium (Cs), tellurium (Te), antimony (Sb), tin (Sn) were low in concentration, but some radioisotopes were similar in the changes of element concentration, indicating possible sources of elements consistent between samples. These elements should be included in monitoring efforts. Zirconium concentration in Taoyuan Guan-sing algal reefs reached 4,462 ppm andon average it was 747 ppm. In comparison, the maximum value in north coast algal reefs was 181 ppm, and on average it was only 78 ppm. Especially in the coastal areas of Guanyin, zirconium was still in high concentration of 1,800 ppm at 250 m offshore, showing land-based sources of zirconium. Titanium was 5,735 ppm in Guan-sing algal reefs coast, and the maximum in north coast was 1,883 ppm; Strontium was 4,622 ppm, and the maximum value was 1,808 ppm in the north coast. Strontium, titanium, zirconium contents were higher than that in the control samplings of north coast, showing external contamination. Evidently pollutants have infiltrated the earthwork fillings in artificial snake-cage dyke and Hsiaofanli Creek, Hsinwu Creek, Houhu Creek and Shetzu Creek. Shihmen Reservoir silt piled on the beach of Yongan Fishing Port, and Sinwu District, Taoyuan might also contain pollutants. Further stringent investigations should be conducted to examine possible sources of pollution.