臺灣東南部海岸底質重金屬含量分析

An Analysis of heavy metal contents along the coast of southeastern Taiwan

本研究針對臺灣東南部海岸底質重金屬調查，範圍北起白守蓮海岸，南至小野柳，海岸線長約60公里，依其地理位置分為9段海岸，再依海岸潮間帶棲地差異設置40採樣站，底質區分為岩石、泥土、砂礫、草澤、生物礁等5類，調查期間為2016-2017年，第2年為重複採樣，各樣本以X-射線螢光光譜儀進行32種重金屬濃度測定，共計251樣本。多數元素濃度最大值與平均值差異大，顯示多數元素的含量在樣本間並不均質，棲地類型有差異，除了部分有施工的採樣站外，兩個不同的年度整體無顯著差異。本研究採用多變數分析以定量數據來計算樣本之相關性，依據主成分分析之分布序列圖及群團分析樹狀圖的結果概分為4群。第I群之鉻、鎳，在杉原南海岸段及白石牛海岸段的樣點偏高，杉原南海岸段及白石牛海岸段之鉻最大值611.40ppm、平均值142.11ppm（n＝30），高於桃園最大值，位於觀音工業區外側富林溪口採樣站，更遠高於新竹（不含集塵灰或爐石之垃圾填埋場）及苗栗海岸，另杉原南的鎳354.90ppm也呈現偏高。第II群的鈦、鐵在砂礫底質的樣點偏高，與西海岸的趨勢相符。第III群的硫在郡界海岸段測得較高的值，最大值19439.61ppm、平均值10221.48ppm（n＝6），高於桃園海岸最高的草漯採樣站，更遠高於新竹及苗栗海岸，在郡界海岸段測得較高的數值包括硫、銣、釷、鉬等元素都是第III群的元素，砷在郡界亦有較高的數值，但歸入第IV群。第IV群中有鉛、錳、砷、汞在小野柳呈現多個離群高值，砷在郡界、小野柳有較高的數值，小野柳的鉛91.16 ppm和錳2755.87 ppm皆偏高。上述這些數據皆顯示有異常外來污染，應持續探查。鈣含量與生物造礁有關，東南海岸的樣本最大值及平均值皆較西北海岸為高，表示造礁後沒有太多的沈積物覆蓋。基翬港的礁石中鈣含量最大，顯示礁體最為健康。

This study is an investigation of heavy metal contents along a 60 km coastline in southeastern Taiwan. The coast between Baishoulian Coast and Xiaoyeliu was divided into nine segments according to estuary and geographical locations to obtain habitat samples. Stations were established based on geographical characteristics, and matrix along coasts were divided into five types: rock, soil, grit, grass, and reefs. A total of 251 samples were gathered to measure the concentration of 32 heavy metals by X-ray fluorescence spectrometer from 2016 to 2017, while repeated sampling was conducted in the second year. The maximum concentration of most elements was significantly different from the average value, indicating that the content of most elements was not homogeneous between sampling stations. There was no significant difference between 2016 and 2017, except for a few sampling stations that were under construction. Multivariate statistical analysis was used to quantifiably verify relevance of samples. Ordination of principal component analysis and dendrogram of cluster analysis showed four groups. The values of chromium (Cr) and nickel (Ni) in Group I were highest. Chromium was measured at 611.40ppm with an average of 142.11ppm (n=30) in Shanyuan and Baishiniu, which was higher than that at the sampling station of the Fulin estuary outside of Guanyin Industrial Park in Taoyuan, and much higher than those in Hsinchu (excluding the landfill of electric arc furnace dust or hearthstone) and Miaoli. The 354.90ppm of nickel in Shanyuan was also higher than that in the surrounding areas. The titanium (Ti) and iron (Fe) values of Group II were higher in grit (sand and gravel), which was consistent with the trend of the west coast. The sulfur (S) of Group III was measured at a higher value in Junjie. The maximum sulfur content of 19439.61ppm and an average value of 10221.48ppm (n=6) were higher than that measured in the highest sampling station on Caota coast in Taoyuan, and much higher than those on the coasts of Hsinchu and Miaoli. In Junjie, sulphur, antimony (Rb), bismuth (Th), and molybdenum (Mo) were found in Group III. Arsenic (As) in Junjie was also higher than that in the surrounding areas, but arsenic was inducted into Group IV. Lead (Pb), manganese (Mn), arsenic, and mercury (Hg) in Group IV showed outlying values in Xiaoyeliu. Arsenic had higher value in Junjie and Xiaoyeliu; and there were 91.16 ppm of lead and 2755.87 ppm of manganese in Xiaoyeliu. The data mentioned above showed abnormal external pollution and should be continuously researched into. The calcium (Ca) content was related to bio-reef. The maximum and average values of the samples on the southeast coast were higher than those on the northwest coast, indicating that there were not too much sediment covering the reefs. The calcium content in the reefs in Jihui Port was the highest, indicating that the reefs there were the healthiest.