玄武岩及蛇紋岩母質土壤之性質與六價鉻生成之比較

Comparison in the differences of soil properties and Cr(VI) generation between basalt and serpentine soils

余俊德(Jun-De Yu)

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(2013年)

https://doi.org/10.6346/NPUST.2013.00131

摘要

花東地區的蛇紋岩和澎湖地區的玄武岩分屬超基性及基性岩類，而蛇紋岩和玄武岩類風化形成的土壤，其重金屬背景濃度偏高，如鐵、鉻、鎳、鈷等，尤其是蛇紋岩含有極高鉻、鎳背景濃度。本論文探討玄武岩與蛇紋岩土壤性質的差異及在不同pH值下土壤中六價鉻的生成及濃度變化。實驗中以蛇紋岩及玄武岩土壤剖面樣品探討其理化性質與鉻、鎳全量，並進行添加酸的孵育，以了解供試土樣之六價鉻濃度變化。研究結果發現，鉻及鎳全量濃度皆高於一般土壤，而蛇紋岩土壤的濃度不僅高於玄武岩土壤，且大部分土樣已超過台灣的土壤污染管制標準。從序列萃取可看出鉻及鎳在型態劃分中，主要是被固定在礦物晶格內的殘餘態。蛇紋岩土壤的六價鉻濃度及鉻氧化能力皆大於玄武岩土壤，且因易還原性錳濃度提高而增加。蛇紋岩土壤加酸孵育結果顯示，加入酸濃度越高，六價鉻濃度越低而水溶性鈣與鎂濃度則越高，顯示加酸可溶出矽酸鹽中的鈣、鎂以及微量的鉻，但不足以溶出固定在鉻鐵礦中的鉻。

關鍵字

玄武岩土壤 ； 蛇紋岩土壤 ； 六價鉻 ； 酸化孵育 ； 重金屬

並列摘要

Serpentinites from eastern Taiwan and basalts from Penghu are ultramafic and mafic rocks. The soils derived from serpentinite and basalt contain high concentrations of heavy metals like Fe, Cr, Ni and Co, especially in serpentine soils with enriched Cr and Ni. The purposes of this study were to explore the differences of soil properties and to understand Cr(VI) generation with differences pH values between basaltic and serpentine soils. According to the experimental results, totel contents of Cr and Ni in serpentine soils were higher than those in basalt soils, which were over the soil pollution control standards of Taiwan. The sequential extraction shows that Cr and Ni were mainly from the mineral lattices, and thus concentrated in the residual fractions. Cr(VI) concentration and Cr oxidation capacity in the serpentine soils were higher than those in the basalt soils, and increased with the easily reducible Mn concentration. The results of soil incubation with hydrogen ion indicated that and Cr(VI) concentration decreased with the increas of added acid, suggesting that Cr dominantly existed as Cr(III). However, the concentrations of soluble Ca and Mg increased with the increase of added acid, revealing that the Ca and Mg dissolved from silicates, but hardly from chromite.

並列關鍵字

basic soil ； serpentinitic soil ； Cr(VI) ； acid incubation ； heavy metal

參考文獻

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