新竹市濱海野生動物保護區土壤重金屬含量分析

Heavy Metal Contents in Soil in Hsinchu City Coastal Wildlife Refuge

為瞭解新竹市濱海野生動物保護區內之污染現況，本研究設置46處採樣站，於2012－2013年進行採樣，以X-射線螢光光譜儀進行32種重金屬濃度檢測，取得279樣本資料進入分析。以定量數據來計算樣站間之差異，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，討論紅樹林清除前後土壤中重金屬變化。新竹濱海之頭前溪口、鹽港溪口南側、海山漁港北側等3處沙質灘地，以及移除紅樹林後台灣招潮蟹棲地的復育區和鴨嘴海豆芽棲地，屬於污染程度低的區域。大压溪口至美山間的老熟紅樹林內灘地測得鋅271 ppm、鉛88 ppm、銅106 ppm、砷23 ppm、鐵34,466 ppm、錳893 ppm、鈦4,144 ppm、銣114 ppm、釷23 ppm、鈷266 ppm、釩105 ppm、硫1,696 ppm及鉀14,960 ppm等多項元素的濃度較其他分區為高。紅樹林內鉀、硫濃度高，越是老熟林濃度越高，鉀濃度在樣站間的變化與多項元素有高度相關，硫在紅樹林清除前後平均值差異大，特別是樹齡較大的地區，但因樣站內的變異也很大，故顯著性不高。紅樹林清除後可降低土壤中重金屬濃度，海山罟以人力進行紅樹林移除在移除初時，鋅是顯著增加，隔一年後多項元素的數值都有下降的趨勢，大压溪口至美山海岸以機械移除紅樹林初時，鉛、鋅、銅、鐵、錳等元素濃度有極顯著的降低，其所營造之棲地，對增加生物多樣性應有正面效益。

This study was conducted to investigate heavy metal contents in Hsinchu city coastal wildlife refuge and Touqian estuary in northwest Taiwan in order to understand the current situation of pollutions. Forty-six sampling stations were set up, and 279 samples data were obtained in 2012-2013. Every sample was measured for 32 heavy metal contents by X- ray fluorescence spectrometer. Multivariate statistical analysis, ordination of principal component analysis and dendrogram of cluster analysis were used for quantitative analysis. Changes of heavy metals in the soil before and after mangrove was removed were analyzed. Areas of low pollution included sandy beaches in Touqian estuary, Yan-gang estuary and Hi-shan harbor, as well as the habitats of Uca formosensis and Lingula anatina after mangrove removal. Investigation in the mature mangrove beaches from Tachuang estuary to Mae-shan coastal area showed 271 ppm zinc, 88 ppm lead, 106 ppm copper, 23 ppm arsenic, 34,466 ppm iron, 893 ppm manganese, 4,144 ppm titanium, 114 ppm rubidium, 23 ppm thorium, 266 ppm cobalt, 105 ppm vanadium, and 14,960 ppm sulfur, indicating higher concentrations than other areas. The concentration of potassium and sulfur was higher in mangrove beaches, and the more mature the forest the higher the concentration. In addition, potassium concentration change between sampling stations highly correlated with a number of elements. The average value of sulfur was different before and after mangrove removal. It was especially different in the older and larger forest, but the kind of variation within the sampling stations was also too great to account for any significance. After clearing the mangroves the concentration of heavy metals in the soil reduced. When mangrove was cleared manually in Haishangu, zinc significantly increased initially, but the concentration of a number of elements decreased in the following year. After mangrove was cleared by machinery from Tachuang estuary to Maeshan coastal area, lead, zinc, copper, iron, manganese and other elements showed significant reduction in concentration initially, showing biodiversity positively benefited by the clearance.