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青岛胶州湾沉积物痕量元素黄铁矿化程度及其剖面类型
Pyritization of Trace Elements in Sediments of the Jiaozhou Bay, Qingdao, China
【摘要】 为了探索青岛近海不同沉积环境下不同痕量元素的黄铁矿化规律,2003年5月潜水员潜入海底采集了4个不同沉积环境的未扰动柱样,并利用HuertaDiazandMorse(1990)连续提取技术测试分析了沉积物痕量金属的不同存在形式(活性态和黄铁矿结合态)在垂直剖面上的分布规律.结果表明:除了在涨潮三角洲上部沉积和潮下带沉积物柱子的Cd和Cr外,痕量元素的黄铁矿化度的增高取决于其相应剖面上的DOP的增高;并且不同痕量元素向黄铁矿中转移的规模存在着较大的差别,即元素As、Hg和Mo转移的规模最大,Cu、Zn、Cd、Cr、Co和Ni中等,Pb和Mn最小;此外,还进一步揭示了河流三角洲沉积物的下部各元素的黄铁矿化程度高,而潮下带沉积物以及涨潮三角洲沉积物低.最后指出在河口水下三角洲进行的清淤工作应注意黄铁矿结合态痕量元素的活化而产生生物有效的毒性元素.
【Abstract】 To determine the pyritization characteristics of reactive trace elements in different anoxic marine sediments, 4 undisturbed cores were sampled by a diver in May 2003. The chemical speciations of the trace elements versus depth were performed using modified sequential extraction procedures from Huerta-Diaz and Morse (1990). Results indicate that the degree of trace metal pyritization (DTMP) of most trace metals increased with increasing DOP. However, for As, Hg and Mo, the DTMP/DOP values were generally above the 1∶1 ratio line irrespective of the type of sedimentary environment involved, whereas the transition metals Cu, Zn, Cd, Cr, Co and Ni displayed a close to linear increase in DTMP with DOP and moderate incorporation into pyrite. Pb and Mn were also gradually incorporated into the pyrite phase but without reaching the DTMP levels exhibited by the above metals. These results are consistent with the chemical attributes of these different classes of trace elements. Availability of organic matter content and sedimentary rate are apparently important factors controlling the incorporation of Cu, Zn, Co, Ni, Cr, Cd and Mn into pyrite in Jiaozhou Bay. The authors conclude that special attention must be paid to during dredging activities to protect the pyrite fraction from being oxidized, especially where activity is carried out down to 20cm in river delta sediments.
【Key words】 sediment; reactive fraction; pyrite fraction; pyritization; Jiaozhou Bay of Qingdao.;
- 【文献出处】 地球科学 , 编辑部邮箱 ,2006年02期
- 【分类号】P618.31
- 【被引频次】8
- 【下载频次】309