| 黄河沉积物重金属时空分布与污染评价 |
| 摘要点击 3311 全文点击 1233 投稿时间：2021-08-10 修订日期：2021-10-04 |
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| 中文关键词 黄河 沉积物 重金属 时空分布 污染评价 |
| 英文关键词 Yellow River sediments heavy metals spatial-temporal distribution pollution assessment |
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| 中文摘要 |
| 重金属污染由于其毒性、持久性、非生物降解性和生物累积性等特点，对水生生态系统存在着严重威胁，沉积物粒径越细，比表面积越大，对重金属的吸附作用越强，而多沙黄河中泥沙颗粒细且易悬浮.基于此，为了明确黄河沉积物中（<63 μm）重金属的时空分布特征和存在的污染风险.分别在2019年春秋两季（4~5月和9~10月）对黄河进行调查，通过野外调查和室内实验分析，结果发现：①黄河表层沉积物中的10种重金属含量大小排序为：Mn>V>Cr>Zn>Ni>Cu>As>Pb>Co>Cd，只有V、As和Cd的平均含量在春季和秋季高于黄土元素背景值，10种重金属含量在春季整体变化趋势为源区至中游逐渐升高后至下游降低.②在不同时空条件下，黄河表层沉积物中除Cd以外9种重金属的含量都有显著差异，时空因素的共同作用导致中游区域的这9种重金属含量高于其他区域.③潜在生态危害指数（RI）表明，黄河表层沉积物只有Cd处于中等生态危害，其余皆处于轻生态危害；地累积指数（Igeo）表明，除As和Cd处于轻度污染外，黄河沉积物整体呈无污染~轻度污染.为减轻黄河表层沉积物中重金属带来的健康生态危害，应注意对As和Cd污染的防控，尤其是甘宁蒙段和中游库区. |
| 英文摘要 |
| Heavy metal pollution poses a serious threat to aquatic ecosystems due to its characteristics of toxicity, persistence, non-biodegradability, and bioaccumulation. Adsorption of heavy metals by sediments is enhanced when the particle size becomes finer, and the specific surface area becomes larger. The sediments of the Yellow River have the characteristics of fine particle size and easy suspension. Based on these characteristics, to clarify the spatial-temporal distribution and the ecological risk of heavy metals in the Yellow River surface sediments (<63 μm), an investigation was taken in spring and autumn (April to May and September to October, respectively) of 2019. Through the field investigation and laboratory experiment analysis, it was found that:① The order of the 10 heavy metal contents in the surface sediments of the Yellow River was:Mn>V>Cr>Zn>Ni>Cu>As>Pb>Co>Cd; the average contents of V, As, and Cd were higher than the background value of loess rock in two seasons. The overall change trend of the 10 heavy metal contents in spring was gradually increased from the source area to the middle reaches and then decreased to the downstream. ② Under the condition of different spatial-temporal distribution, the contents of nine heavy metals in the surface sediments of the Yellow River had significant differences, except that of Cd. The contents of these nine heavy metals in the middle reaches of the Yellow River were higher than those in other regions due to the interaction effects of region and season. ③ The ecological risk index (RI) showed that Cd in the surface sediments of the Yellow River was at a moderate ecological risk, and the rest were at a low ecological risk. The index of geo-accumulation (Igeo) showed that except for As and Cd, which were at a lightly polluted level, the remaining heavy metals in the surface sediments of the Yellow River were at a pollution-free to slightly polluted level. To reduce the health and ecological risks caused by heavy metals in the surface sediments of the Yellow River, the prevention and control measures against As and Cd pollution deserved attention, especially in the Gansu-Ningxia-Inner Mongolia section and the reservoir area in the middle reaches of the Yellow River. |
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