程海沉积物重金属时空变化及人为污染与潜在生态风险

发布时间：2018-03-11 20:22

本文选题：沉积物　切入点：重金属　出处：《环境科学》2017年10期 　论文类型：期刊论文

【摘要】：沉积物重金属污染是影响湖泊等水体环境质量与健康的主要因素之一.通过对程海9个沉积短岩芯中10种金属元素含量的分析,在~(210)Pb与~(137)Cs定年的基础上,研究了沉积物中重金属含量与污染的时空变化特征;采用潜在生态风险指数法与沉积物质量基准法、并参考重金属污染水平,评估了表层沉积物重金属的潜在生态风险.结果表明,各岩芯不同年代沉积物中,除了Cd含量变化较大之外(变异系数为0.59),其余各金属元素含量变化均较小(变异系数小于0.20);空间上,各岩芯之间每一种金属的平均含量差异较小,最大值与最小值的比值为1.2~1.8,显示了不同湖区重金属较为相似的富集规律.沉积物中主要污染元素为Cd、Pb和Hg,其中Cd和Pb污染始于20世纪80年代中期;近十年来Cd污染程度稍有下降,但仍呈中等污染水平,而Pb污染程度持续增加,属于弱污染水平;Hg污染始于20世纪90年代末期,呈弱污染水平;而As、Cu和Zn仅在部分近表层沉积物呈现较弱污染.空间上,沉积物中重金属污染水平并未表现出明显的趋势.除了大气沉降(主要为有色金属冶炼释放)输入之外,程海沉积物重金属污染还可能受到农业面源与生活污水排放的影响.表层沉积物中As、Cu、Ni、Pb和Zn具有较低的潜在生态风险,Hg和Cd具有中-高潜在生态风险.
[Abstract]:The pollution of heavy metals in sediments is one of the main factors affecting the environmental quality and health of lakes and other water bodies. The temporal and spatial variation characteristics of heavy metal content and pollution in sediment were studied, and the potential ecological risk index method and sediment quality standard method were used, and the heavy metal pollution level was referred to. The potential ecological risk of heavy metals in surface sediments was evaluated. Except for the large variation of CD content (coefficient of variation is 0.59), the content of other metal elements varies less (the coefficient of variation is less than 0.20); in space, the average content of each metal varies from one core to another. The ratio of maximum value to minimum value is 1. 2 ~ 1. 8, which shows that the enrichment law of heavy metals in different lakes is similar. The main pollution elements in sediments are CD, Pb and Pb, among which CD and Pb pollution began in the middle of 1980s. In the last ten years, CD pollution level decreased slightly, but it still showed moderate pollution level, while Pb pollution level continued to increase, which belongs to weak pollution level and Hg pollution level, which began in the end of 1990s and showed weak pollution level. In space, the heavy metal pollution level in the sediments did not show a significant trend, except for the atmospheric deposition (mainly non-ferrous metal smelting release) input. Heavy metal pollution in sediments of Chenghai may also be affected by agricultural non-point source and domestic sewage discharges. The potential ecological risks of Pb and Zn in surface sediments are lower than those of Hg and CD with medium and high potential ecological risks.
【作者单位】：中国科学院南京地理与湖泊研究所湖泊与环境国家重点实验室;中国科学院大学;山东师范大学地理与环境学院;
【基金】：科技部科技基础性工作专项(2014FY110400) 国家自然科学基金项目(41672354,41271214)
【分类号】：X524

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