中文关键词
汝溪河重金属沉积物空间分布生物毒害效应 | 英文关键词Ruxi Riverheavy metalssedimentspatial distributionbiological toxic effect |
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| 中文摘要 |
| 为了解三峡库区支流沉积物重金属空间分布、来源及生物毒害效应，选择典型入库支流汝溪河，分4个区域12个采样点采集沉积物柱状样和沿岸土壤样品，分析了Cr、Ni、Cu、Mn、Zn、Cd、Pb和Hg这8种重金属的空间和垂向分布特征.结果表明，沉积物中Cr、Ni、Cu、Mn、Zn、Cd、Pb、Hg平均含量分别为（79.60±11.87）mg·kg-1、（41.340±4.999）mg·kg-1、（32.69±8.70）mg·kg-1、（823.34±125.76）mg·kg-1、（122.11±22.82）mg·kg-1、（0.393±0.140）mg·kg-1、（29.122±6.811）mg·kg-1和（74.84±39.50）μg·kg-1，8种重金属含量均超过长江水系沉积物背景值，空间上总体表现为受汝溪场镇生活影响河段 > 回水区 > 自然河段，回水区河道沿岸沉积物及土壤中重金属含量均远低于沉积物中，说明河道沿岸沉积物和土壤并不是汝溪河回水区沉积物重金属的主要污染来源.在垂向分布上，受汝溪场镇生活影响河段重金属（除Pb外）含量最大值均出现在8cm处，而自然河段和回水区重金属含量随深度的增加呈下降的趋势.除Ni外，其他几种重金属之间具有显著相关（P<0.01），说明汝溪河重金属存在一定的同源性.地累积指数评价得出汝溪河整体呈现Cd和Zn的轻度至偏中度污染.生物毒性效应评价得出，Ni有10%~75%可能对生物造成毒害效应，Cd、Zn、Hg、Cu、Pb和Cr有<10%的可能会出现生物毒害效应.综合效应系数表明汝溪河沉积物重金属的生物毒害风险为低级至中低级. |
| 英文摘要 |
| Sediment column and soil samples collected from 12 sampling sites in four regions of the Ruxi River, a typical tributary of the Three Gorges Reservoir, were analyzed for eight selected heavy metals including Cr, Ni, Cu, Mn, Zn, Cd, Pb, and Hg to evaluate their spatial and vertical distribution, source, and biological toxic effects. The results showed that the average concentrations of heavy metals were (79.60±11.87), (41.340±4.999), (32.69±8.70), (823.34±125.76), (122.11±22.82), (0.393±0.140), and (29.122±6.811) mg·kg-1 for Cr, Ni, Cu, Mn, Zn, Cd, and Pb, respectively, and (74.84±39.50) μg·kg-1 for Hg, all of which exceeded the sediment background values of the Yangtze River. A spatial trend of decreasing metal concentrations was observed from the reach influenced by the human activities of Ruxi town to the backwater zone and then to the natural river reach. Moreover, in the backwater zone, the heavy metals in sediments and soil along the river were significantly lower than those in sediments, indicating that the sediments and soil were not one primary source for these metals in backwater zone sediment. From the vertical distribution of sediment, in addition to Pb, the highest level of metals was observed at 8 cm in the reach influenced by human activities, and their concentrations decreased with sediment depth in the backwater zone and natural river beach. Significant correlation was found between all the heavy metals (P<0.01, except Ni), indicating a potential homology of these metals in the Ruxi River. Evaluation results of the geoaccumulation index reveal that there exists light to partial moderate Cd and Zn pollution in the Ruxi River. The evaluation of biotoxicity effects showed that Ni was likely to have toxic effects on organisms with a probability of 10% to 75%, and Cd, Zn, Hg, Cu, Pb, and Cr are likely to have biotoxic effects at<10% probability. The combined effect values of multiple metals indicated that the risk of adverse effects was between low and lower medium in the sediments of the Ruxi River. |
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