渭河西安段沉积物中重金属元素含量分布及其风险评价

Distribution of Contents of Heavy Metal Elements in Sediments of Xi’an Section of Wei River and Their Risk Evaluation

为了分析渭河西安段沉积物中的重金属元素的污染现状、风险和来源,在渭河西安段及其支流沣河,共设置了38个采样点,采集了沉积物样品,测定了沉积物中重金属元素Cr、Co、Ni、Cu、Zn、V、Ba和Pb的含量;采用克里金插值法,分析重金属元素含量的空间分布;采用Pearson相关分析法,分析了重金属元素的来源;采用污染负荷指数法和潜在生态风险指数法,对渭河西安段沉积物中重金属元素污染现状和生态风险进行评价。研究结果表明,渭河西安段沉积物中的8种重金属元素含量在部分区域富集,其中重金属元素Co和Ba的富集程度相对较大;重金属元素Cr、Ni、Cu、Zn和V主要来源于生活污染物,重金属元素Co、Ba和Pb主要来源于工业污染物;重金属元素Co的污染最为严重,其次为Ba元素,二者是造成渭河西安段沉积物中重金属污染的主要元素;渭河西安段干流沉积物中重金属污染的综合潜在生态风险总体为低风险,而支流沣河沉积物中重金属污染的综合潜在生态风险为中等风险或者较高风险。

In order to analyze the current situation, risk and sources of heavy metal pollution in the sediments of Xi’an section of Wei River, 38 sampling points were set up in Xi’an section of Wei River and its tributary Feng River. The sediment samples were collected, the contents of Cr, Co, Ni, Cu, Zn, V, Ba and Pb elements were measured. The Kriging interpolation method was used to analyze the spatial distribution of heavy metals.The Pearson correlation analysis method was used to analyze sources of heavy metal, and the pollution load index method and the potential ecological risk index method were used to evaluate the current situation of heavy metal pollution and ecological risk. The results showed that contents of eight kinds of heavy metal elements in sediments of Xi’an section of Wei River were enriched in a some regions, among which the enrichment of Co and Ba elements was relatively high and the content of Ni and Cu elements was low. Five heavy metal elements(Cr, Ni, Cu, Zn and V) were mainly sources of domestic pollution, while Co, Ba and Pb were mainly industrial sources. The pollution of heavy metals Co was the most serious, followed by Ba elements, and Co and Ba were the main elements causing heavy metal pollution in the Xi’an section of the Wei River. The degree of pollution in the tributaries was greater than that in the main streams, and the combined potential ecological risk of sediments in Wei River was generally low risk, while the Feng River was generally moderate to high risk.