| 沉积物中氧化物结合态镉对芦苇的生物有效性研究：氧化物种类、结合形式、老化的影响 |
| 摘要点击 1856 全文点击 1103 投稿时间：2008-11-24 修订日期：2009-02-23 |
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| 中文关键词 镉 氢氧化铁 氢氧化铝 老化 吸附 共沉淀 生物有效性 |
| 英文关键词 cadmium iron hydroxide aluminum hydroxide aging adsorption coprecipitation bioavailability |
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| 中文摘要 |
| 沉积物中重金属的生物有效性在很大程度上取决于其赋存形态.选用沉积物中2种典型氢氧化物矿物：氢氧化铁和氢氧化铝，以水培法和矿物结合态Cd为培养介质，以芦苇为受试植物，研究环境中吸附和共沉淀态Cd生物有效性差别，并探究老化过程对生物有效性的影响.经过13 d的培养，发现2种结合形式的Cd均可被芦苇富集，不同处理体系中富集强度不同，根中富集量为9.1～37.8 mg·kg-1；地上部分富集量为0～10.0 mg·kg-1.其中，结合在Fe0.5Al0.5(OH)3矿物上的Cd的生物有效性最大，其次是Fe(OH)3和老化的Fe0.5Al0.5(OH)3，富集量最少的是老化的Fe(OH)3的处理.采用2种低分子量有机酸对Cd进行解吸实验，Cd的解吸规律与芦苇对Cd的富集规律一致.因此，共沉淀处理降低了Cd的富集，矿物的理化性质决定了含铝矿物对Cd的结合较差，老化作用抑制了吸附态Cd的富集，有机酸解吸实验也验证了不同形态Cd生物有效性的差异. |
| 英文摘要 |
| The bioavailability of heavy metals in sediments is largely controlled by their speciation. Effects of different Cd speciation associated with metal hydroxide on Cd bioavailability were studied. Iron and aluminum hydroxides were chosen as representatives of the oxides commonly present in sediments. In cultivar system, Hoagland solution was used as nutrition supply, and metal hydroxide associated with Cd as the only source of contamination and Phragmites australis was induced to study Cd bioaccumulation. After 13 d cultivation, Cd was uptaken and accumulated in P. australis, with different bioaccumulation from 9.1 to 37.8 mg·kg-1 in root; and 0 to 10.0 mg·kg-1 in shoot. Hereinto, the P. australis cultivated in Fe0.5Al0.5(OH)3 medium was found to have accumulated the largest amount of Cd in root, followed by those in Fe(OH)3 and agedFe0.5Al0.5(OH)3, the lowest root concentration of Cd was observed in the plants cultivated in agedFe(OH)3． Desorption order of Cd by organic acid was consistent with the Cd accumulation in P. australis.Thus, coprecipitation treatment decreases the bioavailability of Cd; association of aluminum hydroxide with Cd is poor due to its physicochemical property; aging treatment significantly restrict the accumulation of adsorbed Cd; desorption by organic acid verify the discrepancy in bioavailability of different speciation of Cd. |
