Wang Bo, Zhao Shuang, Xia Dun-sheng, Yu Ye, Tian Shi-li, Jia Jia, Jiang Xiao-rong
Key Laboratory of Western China's Environmental System (Ministry of Education), Lanzhou University, Lanzhou 730000, China.
Huan Jing Ke Xue. 2011 May;32(5):1430-40.
The contents of As, Co, Cr, Cu, Ni, Pb, V and Zn in the surface sediments from 8 rivers in urban area in Lanzhou were monitored by ecological risk which was assessed by the potential ecological Håkanson index, and the index of geoaccumulation (Igeo), sediment enrichment factor (R), and environmental magnetism. The results showed that: (1) the potential ecological risk of heavy metals of As, Co, Ni, V in surface sediments from 8 rivers were low, which belonged to low ecological risk. But the risk of heave metals Cr, Pb, Zn in surface sediments from Yuer river was high, which belonged to middle ecological risk, and in downstream of Yuer river, the element of Cu belonged to high ecological risk. (2) The rivers in Lanzhou could be divided into four groups according to the heavy mental pollution degree: first type, such as Paihong river, Shier river, Yuer river and Shuimo river, called downstream concentrate type; second type, such as Qili river, called upstream concentrate type; third type, such as Luoguo river and Dasha river, called less affected type; fourth type, Lanni river, which polluted heavily in up and downstream; (3) The correlation analysis between magnetic parameters and element contents show that the parameters which mainly reflect the concentration of the magnetic minerals (X, SIRM, Ms) have close association with Cr, Ni, Pb, Zn, Cu, So we can infer that the magnetic minerals in deposits samples mainly came from electroplating effluent, motor vehicle emission, and domestic sewage. SIRM/X shows a strong correlation with Cr, Ni, Pb, Zn, indicating the distribution of anthropogenic particulates. (4) The magnetic minerals(X, SIRM, Ms) have a strong correlation with the geoaccumulation (Igeo) than potential ecological risk index and enrichment factor (R). These results suggest a possible approach for source identification of magnetic material in pollution studies and the validity of using magnetic measurements to mapping the polluted area.
通过潜在生态危害指数、地累积指数（Igeo）、沉积物富集系数（R）和环境磁学方法对兰州市区8条河流表层沉积物中砷（As）、钴（Co）、铬（Cr）、铜（Cu）、镍（Ni）、铅（Pb）、钒（V）和锌（Zn）的含量进行监测并评估其生态风险。结果表明：（1）8条河流表层沉积物中As、Co、Ni、V重金属的潜在生态风险较低，属于低生态风险。但鱼儿河表层沉积物中Cr、Pb、Zn重金属风险较高，属于中等生态风险，且在鱼儿河下游，Cu元素属于高生态风险。（2）兰州河流按重金属污染程度可分为四类：第一类，如排洪沟、十二河、鱼儿河、水磨河，称为下游集中型；第二类，如七里河，称为上游集中型；第三类，如罗锅河、大沙河，称为轻度影响型；第四类，烂泥沟，上下游污染严重；（3）磁学参数与元素含量的相关性分析表明，主要反映磁性矿物浓度的参数（X、SIRM、Ms）与Cr、Ni、Pb、Zn、Cu密切相关，因此可以推断沉积物样品中的磁性矿物主要来自电镀废水、机动车尾气排放和生活污水。SIRM/X与Cr、Ni、Pb、Zn有很强的相关性，表明人为颗粒物的分布。（4）磁性矿物（X、SIRM、Ms）与地累积指数（Igeo）的相关性比与潜在生态风险指数和富集系数（R）的相关性更强。这些结果为污染研究中磁性物质的来源识别提供了一种可能的方法，也验证了利用磁学测量绘制污染区域的有效性。
