南崁溪水質與底泥品質之主成分分析

Abstract

南崁溪由於流域內工業區與住宅區及農牧業鄰立，為近年來污染較為嚴重的河川之一，目前仍為中度污染的河川。因此，為了找出目前南崁溪急需解決的問題與關鍵的影響因子，研究利用主成分分析探討水體與底泥中各變數項的組成及影響環境的主要影響因子，期盼透過統計分析的方法，能夠對南崁溪的水質與底泥之品質控管有更多的助益。根據歷年蒐集資料之主成分分析，發現水質可萃取出五個主成分，依序為生物因子、營養鹽因子、重金屬因子、溫度因子、酸鹼因子；放流水可萃取出兩個主成分，依序為生物因子、酸鹼因子(重金屬銅)；而底泥可萃取出兩個主成分，依序為重金屬因子、塑膠添加劑因子，這三面向共同之影響因子為重金屬因子(重金屬銅)，推測是由於流域內之工業區與工廠所排放的事業放流水所造成，且流域內之底泥因長期遭到受污染的水質與放流水的排放，造成濃度時常超過底泥品質指標的下限值，偶爾超出上限值。根據歷年的資料分析後，發現底泥、放流水與水質中的銅之合格率幾乎皆為歷年最低，依序為31.58%、92.61%、39.47%，由三面向交叉分析後也發現水質、放流水對於底泥品質皆有顯著(100%)之關連性，而主成分分析後的結果也顯示底泥、放流水與水質之共同重要的影響因子皆為重金屬因子(重金屬銅)，其主成分負荷值依序為0.510、0.780、0.919。而重金屬銅的的主要污染範圍以大埔橋最為嚴重，推測源自上游工業區(如林口工業區、華亞科學園區)及鄰近工廠；其次則為大檜溪橋，推測源自東門溪(南崁溪支流)上游的龜山工業區及周遭工廠與南崁溪橋和竹圍大橋為主。

The NanKan River flows through many industrial areas, crowded cities and wide range of agriculture and livestock. The electronic and mechanical manufacturers in this area are highly productive. Hence, the river pollution currently belongs to moderately-polluted river. The principal component analysis (PCA) is used in this study to investigate the variable and main factor of water quality, industrial effluent and sediment in environment. Through statistics analysis to find the key points for solving the problem that improving water quality and sediment in NanKan River. According to the PCA of collected water quality data, it can be found that river water quality can be extracted as five components, biological factor, nutrient factor, heavy metal factor, temperature factor, acid and alkali factor. The effluent data can be extracted as two components, biological factor, acid and alkali factor (copper). The sediment of the NanKan River can be extracted as two components, heavy metal factor and plastic additive factor. The common influencing factor is heavy metal factor (copper), presumably due to the discharge of copper from industrial effluent. The statistics results show that the conformity of copper in the sediment is 31.58 %, the industrial effluent is 92.61 %, and the river water quality is 39.47 % from 2012 to 2016. The Copper concentration in sediment has high connectivity with those of in river water quality and industrial effluent. The results of PCA also show that the co-influencing factor of the sediment, the industrial effluent and river water quality is heavy metal factor (copper), and the principal component loading are 0.510, 0.780 and 0.919. The most severe area of the copper pollution in Dapoo Bridge is speculated from the upstream such as the Linkou Industrial Park and the Hwa Ya Technology Park or other surrounding factories, the next is in Dakwai River Bridge which is from the upstream of Guishan Industrial Park and the bridge in Nankan River and Jhuweida.