| 摘要: | 本研究以台北地區飲用水主要水源之南勢溪與北勢溪為對象，統計分析1990年至2006年水質監測資料，以檢討台北都會區水源水質變化趨勢台北都會區水源水質變化趨勢，評析水質項目為生化需氧量（BOD）、氨氮與總磷、大腸桿菌群與總菌落數，分別代表有機性、營養鹽、細菌性之污染物。研究結果顯示南、北勢溪下游測站兩階段BOD濃度年平均皆符合甲類水體，營養源氨氮、總磷南勢溪則分別增加0.83倍與0.35倍；北勢溪則分別增加2.33倍與1.23倍。1990 - 2006年南、北勢溪BOD、氨氮、總磷平均值之比值分別為 1.31、1.29、1.90倍，南勢溪總菌落數及大腸桿菌群分別為北勢溪之6.73倍及8.05倍。北勢溪上游三個測站兩階段之BOD濃度有逐漸降低趨勢，但營養鹽氨氮、總磷則分別增加0.75-1.0倍與1.07-1.49倍；坪林測站之總菌落數及大腸桿菌群皆為其它二個測站約2.2倍與3.9倍。翡翠水庫上游七個測站18年（1989-2006年）以優養化單一指標或卡爾森綜合指標判斷，水質屬普養狀態，總磷濃度兩階段年平均值由9.20-16.96 μg/L增至20.51-26.38 μg/L，增加翡翠水庫水質優養化潛勢。
The Nan-shi creek and Bei-shi creek are the main drinking water source for 5 million people in Taipei metropolitan. Using water quality data monitored during 1990-2006, this study evaluated the variation tendency of source drinking water qualities in Taipei metropolitan. The biochemical oxygen demand (BOD), ammonium nitrogen (NH4+) and total phosphate (TP), and coliform bacteria are represented for organic, nutrient and bacterial pollutants, respectively.
The result shows that the annual average BOD of both Nan-shi creek and Bei-shi creek is less than 1.0 mg/L. This indicates that water quality of these creeks meet the water quality classification standards of A category. However, the NH4+ and TP increase 0.85 times and 0.35 times in Bei-shi creek, respectively, while they are 2.33 times and 1.23 times in Nan-shi creek during the past decade. Comparing water qualities between these two creeks, it shows that the BOD, TP and coliform bacteria concentrations of Nan-shi creek are 1.31 and 1.90 and 8.05 times, respectively, as that of Bei-shi creek. The results imply that the water pollution in Nan-shi creek is heavier than Bei-shi creek. Furthermore, the water qualities of three monitor stations at the upstream of Bei-shi creek show that the BOD decreases dramatically, while the increases of TP range from 1.07 to 1.49 times. The Calson trophic state index was used to evaluate the trophic state of water quality of Feitsui reservoir. Based on the water qualities of seven monitor stations at upstream of Feitsui reservoir, it shows that the water quality is in mesotrophic state for most time. However, the TP concentration increases from 9.2-16.96 μg/L to 20.51- 26.38μg/L during the past decade. The increase of TP concentration enhances the potential of eutrophication on Feitsui reservoir. Therefore, it is necessary to conduct eutrophication control strategies for protecting drinking water source. |
