蛇紋岩土壤之鉻、鎳萃取濃度和土壤性質之探討

The investigation of extractable Cr and Ni concentrations and soil properties for serpentinitic soils

張祐銓(Yu-Chuan Chang)

指導教授 ： 許正一

國立屏東科技大學/工學院/環境工程與科學系所/碩士(2014年)

https://doi.org/10.6346/NPUST.2014.00132

摘要

全球超基性岩類僅佔陸域地表的1 %，均集中在板塊交界帶上。臺灣本島的蛇紋岩分布主要在中央山脈東翼與海岸山脈的丘陵，另在蘭嶼西北部的集塊岩中，也有蛇紋岩塊的零星分布。本論文選定臺灣花東地區蛇紋岩分布之三個區域（A、B、C）土壤，進行理化性質、王水消化及0.1 N 鹽酸萃取法萃取等方式分析鉻及鎳的關係。研究結果顯示，在理化性質方面，三區土壤樣體之pH值平均範圍在5.8-7.4之間，與一般蛇紋岩土壤之pH值介於4.5-7.5 之間為類似，迴歸分析發現pH值偏鹼性時其鉻及鎳全量有增加之趨勢，當pH值偏酸性時鉻及鎳濃度則較低；供試土壤之鈣/鎂比亦均低於1，甚至低於0.30以下，顯示土壤母質符合蛇紋岩有較高鎂含量之現象，並且鈣/鎂比越高，其鉻及鎳濃度較低；土壤質地因矽酸鹽礦物經風化後形成粘土礦物，且由於沖積及化育時間不同，因此三區之土壤質地變化差異大。王水分析各區之鉻與鎳濃度均遠高於臺灣土壤污染管制標準之250與200 mg/kg。若以0.1 N鹽酸萃取法萃取評估，三區鉻濃度均低於農政單位訂定之有機農業土壤重金屬容許標準10 mg/kg，但鎳在A、C兩區多數已超過其有機農業土壤重金屬容許標準10 mg/kg。

關鍵字

鉻 ； 鎳 ； 王水消化法 ； 0.1 N鹽酸萃取法 ； 蛇紋岩 ； 土壤污染

並列摘要

The proportion accounted for the global ultrabasic rocks is only 1% of the land surface, and they are concentrated in the junction with the plate. Serpentinite in Taiwan are mainly distributed in the Central Ridge and the Coastal Range, and some are scattered in the northwest of Lanyu agglomerate.The study discussed three serpentine soil areas of eastern Taiwan( A, B, and C) and analyzed the relationship between chromium and nickel by using aqua regia digestion and 0.1 N HCl extraction methods.
The results show that the pH of soil samples range between 5.8 and 7.4 and coincide with the pH value of general serpentinitic soils ranging from 4.5 to 7.5. The concentrations of chromium and nickel were found to increase with an increasing pH by regression analysis. Additionally, the calcium/magnesium ratio of samples were all lower than 1.0 even lower than 0.30. It indicated that the soil parent material was consistent with the phenomenon of the high magnesium content in the serpentinite. The concentrations of chromium and nickel were found to decrease with an increasing calcium/magnesium ratio. The properties of three areas’ soil varied widely because the silicate changed to different clay minerals by weathering processes and also the different alluvial and genesis time.
The concentrations of chromium and nickel by using aqua regia digestion are much higher than the soil pollution control standards in Taiwan (250 and 200 mg/kg). While using the extraction assess 0.1 N HCl extraction method, the concentration of chromium in three areas were lower than the soil heavy metals permitted standard of 10 mg/kg for organic farming in Taiwan, and the nickel concentration of most samples in the A and C areas were higher than the permitted standard of 10 mg/kg.

並列關鍵字

chromium ； nickel ； aqua regia digestion ； 0.1 N HCl extraction ； serpentine ； soil contamination

參考文獻

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