Liu Hui, Zhang Kejing, Chai Liyuan, Yang Zhihui, Yang Weichun, Liao Qi, Li Huan, Liu Yi
Institute of Environmental Science and Engineering, School of Metallurgy and Environment, Central South University, Changsha, 410083, China.
National Engineering Research Center for Heavy Metals Pollution Control and Treatment, Changsha, 410083, China.
Arch Environ Contam Toxicol. 2017 Nov;73(4):593-606. doi: 10.1007/s00244-017-0436-3. Epub 2017 Jul 29.
To evaluate intensively the quality of the sediments contaminated by heavy metals and metalloids in the Xiangjiang River, 52 surface sediment samples were collected at 13 sites and different combinations of empirical and theoretical sediment quality indexes, the consensus-based sediment quality guidelines, sediment toxicity degree, and equilibrium partitioning method were applied. The average contents of Cd, Pb, Cu, Zn, Hg, Cr, and As in the sampled surface sediments were significantly higher than the background values of trace elements in soils of Hunan Province, China. Moreover, speciation fraction analyses revealed that Cd, Hg, and Pb in the sediments were dominated by the more bioavailable organic or exchangeable fractions, whereas the major species of As and Cr were the less bioavailable residual fractions after strong acid treatment. In addition, all indexes showed that these metals posed a median-high degree of toxic risk to benthic organisms in sediments from nearly all of the sampling sites along the Xiangjiang River. Cd, followed by Cu and Pb, erected the most severe ecological risk. Pearson correlation and linear regression analyses between the mean PEC quotients, sediment toxicity degree, interstitial water criteria toxic units, and sediment pollution index showed that these indexes were relatively consistent to assess the quality of sediments contaminated by heavy metals and metalloids in the Xiangjiang River. Our results will facilitate the proposal of proper sediment quality guidelines for the Xiangjiang River.
为深入评估湘江中受重金属和类金属污染的沉积物质量，在13个采样点采集了52个表层沉积物样本，并应用了经验性和理论性沉积物质量指标的不同组合、基于共识的沉积物质量指南、沉积物毒性程度以及平衡分配法。所采集的表层沉积物中镉、铅、铜、锌、汞、铬和砷的平均含量显著高于中国湖南省土壤中微量元素的背景值。此外，形态分析表明，沉积物中的镉、汞和铅以生物有效性更高的有机或可交换态为主，而砷和铬的主要形态是经过强酸处理后生物有效性较低的残留态。此外，所有指标均显示，这些金属对湘江几乎所有采样点沉积物中的底栖生物构成中高度毒性风险。镉，其次是铜和铅，构成的生态风险最为严重。平均PEC商、沉积物毒性程度、间隙水标准毒性单位和沉积物污染指数之间的Pearson相关性和线性回归分析表明，这些指标在评估湘江受重金属和类金属污染的沉积物质量方面相对一致。我们的研究结果将有助于为湘江提出合适的沉积物质量指南。
