Department of Environmental Management, Bharathidasan University, Tiruchirappalli 620024, Tamil Nadu, India.
Arch Environ Contam Toxicol. 2013 Jul;65(1):14-23. doi: 10.1007/s00244-013-9886-4. Epub 2013 Mar 22.
Geochemical fractionation of iron (Fe), manganese (Mn), copper (Cu), chromium (Cr), lead (Pb), zinc (Zn), and nickel (Ni) were determined using five-stage sequential extraction in sediments collected from estuarine stretches of Cauvery River delta on the eastern coast of India with emphasis on seasonal variation. Abundance of metals in terms of sum of total fractionations varied in the following order: Fe > Mn > Cr > Zn > Cu > Ni > Pb. Exchangeable fraction, believed to be bioavailable, showed differential abundances during the dry and wet seasons in the following order: Pb > Zn > Cu > Mn > Ni > Cr > Fe and Zn > Cu > Cr > Ni > Mn > Pb > Fe, respectively, indicating the possibility of anthropogenic influence. Among nonlithogenic fraction, organic matter-bound fraction is the second largest and a key scavenger for all of the heavy metals studied except Fe and Mn. A significant portion of Cu-associated organic matter fraction shows strong association of Cu with organic matter at most of the sampling sites. Environmental risk of metals evaluated using risk-assessment code and mobility factor showed low to high risk for Pb, Zn, and Cu. The results of the present study also hint at notable enrichment of heavy metals in the certain pockets of the Cauvery Estuary.
采用五步连续提取法对印度东海岸考维里河三角洲河口处的沉积物进行铁（Fe）、锰（Mn）、铜（Cu）、铬（Cr）、铅（Pb）、锌（Zn）和镍（Ni）的地球化学形态分析，并重点研究季节性变化。金属总量的各形态加和的丰度顺序为：Fe > Mn > Cr > Zn > Cu > Ni > Pb。可交换态（被认为是生物可利用的）在干湿两季的丰度顺序不同，分别为：Pb > Zn > Cu > Mn > Ni > Cr > Fe 和 Zn > Cu > Cr > Ni > Mn > Pb > Fe，表明可能存在人为影响。在非成岩相部分中，有机质结合相是仅次于Fe 和 Mn 的第二大相，也是所有研究重金属的主要俘获相。在大多数采样点，与 Cu 相关的有机质相中，有相当一部分 Cu 与有机质强烈结合。使用风险评估码和迁移因子对金属的环境风险进行评估，结果表明 Pb、Zn 和 Cu 的风险为低到高。本研究的结果还暗示考维里河口的某些区域重金属有明显的富集。
