彰雲海岸濕地土壤重金屬含量分析

Heavy metal monitoring in the soil of Changhua and Yunlin coastal wetlands

為瞭解彰雲海岸濕地之污染現況，本研究依地理位置、河口現況及潮間帶寬度設置採樣站，設置28個固定採樣站，於2022–2023年進行採樣。在每個固定採樣站檢測水體之鹽度、pH值、溶氧飽和度、NO3等，各進行3次樣點檢測，共177筆現場水質、水文檢測資料。每固定採樣站採集上下層土壤各1個樣本，帶回實驗室進行後續處理。土壤粒徑分析砂粒、粘粒、砏粒百分比，2年上下層共121筆資料進入分析。土壤重金屬含量檢測以X-射線螢光光譜儀進行32種重金屬濃度檢測，每樣本各3次重複，2年上下層共393筆資料進入分析，以定量數據來計算採樣站間、不同土層以及不同年度間之差異。檢驗分析結果，發現彰化縣福寶、舊濁水溪口、八洲排水道口、三豐新街海堤採樣站土壤硫化情形嚴重，呈現厭氧狀態，溶氧量偏低。據觀察2023年4–5月有些地區藻華情形嚴重，絲狀綠藻繁生，溶氧過飽和。除芳苑、麥寮、線西，多數採樣站pH值偏低。雲林湖口濕地鹽度顯著高於平均海水鹽度。彰化縣線西採樣站Cu之上層土壤顯著高於下層土壤，且高於其他採樣站，舊濁水溪口採樣站之上下層土壤Cu數值皆偏高，雲林縣金湖採樣站之上下層土壤Cr值顯著高於其他採樣站。有畜牧廢水排入的採樣站，例如彰化福寶、三豐採樣站，其溶氧度偏低，且土壤重金屬如Cu、Zn、Fe、S、Co、Sr、Rb、V、Sc等含量偏高。彰雲海岸有大量的工業區和畜牧養殖廢水排入，綜合分析兩年的採樣數據，採樣站之間的差異很大，年度的差異較為不顯著，顯示許多採樣站的污染是長期累積，對於海岸生態確實已經發生影響。年度的差異以舊濁水溪口較為顯著，2年間的土壤粒徑改變，砂粒比例顯著增加，有多種重金屬有顯著下降。

To investigate heavy metal pollution in the Changhua and Yunlin coastal wetlands, 28 sampling stations were established based on estuary and geographical locations, followed by conducting all samples from 2022 to 2023. Salinity, pH value, dissolved oxygen saturation, and NO3 of samples were seasonally measured at each station three times, resulting in 177 records of water quality and hydrological readings over two years. Soil samples were collected from both upper and lower layers at each station and brought back to the laboratory for soil particle size analysis, including percentage of sand, silt, and clay, yielding a total of 121 data records. Additionally, a total of 393 soil samples from both upper and lower layers over two years were collected for measuring the concentrations of 32 heavy metals using an X-ray fluorescence spectrometer. Quantitative data were then utilized to calculate differences between sampling stations, different soil layers, and different years. The results show severe sulfurization in the soils from various stations, including Fubao, the old Zhuoshui estuary, Bazhou Drainage, and Sanfeng in Changhua county, exhibiting anaerobic conditions with low dissolved oxygen levels. Significant algal blooms were observed in certain areas in April and May 2023, characterized by the proliferation of filamentous green algae and oversaturation of dissolved oxygen. Relatively low pH values were recorded in most of the stations, except for Fangyuan, Mailiao, and Xianxi stations. The salinity in Hukou wetland was significantly higher compared to the average seawater salinity. The upper soil layer at the Xianxi sampling station in Changhua county exhibited significantly higher levels of copper (Cu) than its lower soil layer, and also showed surpassing levels compared to the other stations. The old Zhuoshui estuary station was found with elevated copper (Cu) values in both upper and lower soil layers. Chromium (Cr) values in both upper and lower soil layers at Jinhu station in Yunlin county were significantly higher than those at other stations. Livestock wastewater is discharged to Fubao and Sanfeng stations, leading to low dissolved oxygen levels of water, and the soil at these locations exhibited high concentrations of heavy metals, such as Cu, Zn, Fe, S, Co, Sr, Rb, V, Sc, and others. It is also evident that industrial and livestock farming wastewater is discharged to the Changhua and Yunlin coasts. Data revealed substantial differences between sampling stations, while annual variations were relatively non-significant between years, suggesting that pollution in many stations has accumulated over the long term and is significantly impacting coastal ecology. The annual differences were obviously evident at the old Zhuoshui estuary. Over the two-year period, there was a noticeable increase in the proportion of sand particles and a significant decline in the concentrations of several heavy metals.