Calcite encrustation in macro-algae Chara and its implication to the formation of carbonate-bound cadmium.
Calcite encrustation in macro-algae Chara and its implication to the formation of carbonate-bound cadmium.
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DOI：
10.1016/j.jhazmat.2009.01.068
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发表时间：
2009-08
影响因子：
13.6
通讯作者：
K. Siong;T. Asaeda
中科院分区：
文献类型：
--
作者：
K. Siong;T. Asaeda
研究了大型藻类轮藻（Chara（Stoneworts））方解石（CaCO 3）结垢与植物积累镉（Cd）形态的关系。结果表明，在1μgCdL− 1浓度下，纤维轮藻积累的总Cd（0.3mgkg−1）中有17%为碳酸盐结合态。暴露于10μgCdL− 1的植物中碳酸盐结合态Cd的百分比从年轻菌体（总Ca<50 mgg −1，总Cd：125 mgkg −1）的48%增加到钙化成熟菌体（总Ca：190 mgg −1;总Cd：134 mgkg −1）的63%。基于矿物饱和度计算和连续分馏过程的可靠性分析，沉淀的钙钛矿（CdCO 3）和共沉淀的镉与方解石，发生在轮藻细胞壁的碱性区域，可能是碳酸盐结合镉的形成机制。轮藻草甸下经常发现厚厚的泥灰岩沉积物，这表明植物衰老和分解后沉积物中的Ca以及沉淀或共沉淀的Cd的长期储存。
We studied the relationship between macro-algae Chara (Stoneworts) calcite (CaCO3) encrustation and the speciation of cadmium (Cd) accumulated by the plant. Results showed that 17% of the total Cd (0.3mgkg−1) accumulated by Chara fibrosa exposed to 1μgCdL−1was carbonate-bound. The percentage of carbonate-bound Cd in the plant exposed to 10μgCdL−1increased from 48% in young thalli (total Ca<50mgg−1, total Cd: 125mgkg−1) to 63% in calcified mature thalli (total Ca: 190mgg−1; total Cd: 134mgkg−1). Based on mineral saturation calculation and reliability analysis of the sequential fractionation procedure, precipitation of otavite (CdCO3) and co-precipitation of Cd with calcite, occurring in the alkaline regions of Chara cell wall, are probably the mechanisms of carbonate-bound Cd formation. Thick marl sediment frequently found beneath charophyte meadows suggests a long-term storage of Ca as well as the precipitated or co-precipitated Cd in the sediment after the plant senescence and decomposition.