宁夏阅海底泥重金属空间分布特征及来源解析

为了解宁夏阅海底泥重金属污染现状及其潜在生态风险，解析其重金属污染物来源，结合环境现状，分区域采集14个底泥样品，分析底泥理化性质；运用Arcgis反距离空间插值法（IDW）研究阅海底泥重金属元素空间分布特征，采用地累积指数法和Hakanson潜在生态危害指数法对其污染状况和生态风险进行评估，并利用相关性、主成分以及聚类分析等方法对阅海底泥重金属来源进行解析。结果表明，阅海底泥中汞（Hg）和钴（Co）元素平均含量分别为0.16 mg/kg和19.23 mg/kg，分别达到背景值的5.16和2.24倍，其他重金属元素铅（Pb）、铜（Cu）、砷（As）、镉（Cd）、铬（Cr）含量均超过银川平原引黄灌区土壤对应元素背景值含量；阅海底泥重金属空间分布差异性显著，各重金属元素在芦苇分布区域富集趋势十分明显；重金属元素污染程度表现为：Hg>Co>Pb>Cu>Cd>As>Cr，综合潜在生态风险均值达到 277.21，属中等生态危害范畴，其中 Hg 元素超标严重，贡献率达74.42%。阅海底泥重金属Cr和As元素受自然背景影响明显，而Hg、Co、Pb、Cu和Cd元素则主要来源于鸟粪排放以及人类活动。

Spatial Distribution Characteristics and Source Analysis of Heavy Metals in the Sediments of Yuehai Lake, Ningxia

The heavy metal pollution and potential release risk of sediments are major problems in ecological environment security and treatment such as lakes and wetlands. Collected 14 sediment samples according to the environmental conditions from Yuehai Lake of Ningxia, the content of heavy metal elements was measured and analysis its spatial distribution characteristics. The index of geoaccumulation method and Hakanson potential ecological hazard index method were used to evaluate its pollution status ecological risk, and correlations analysis, principal components analysis, and cluster analysis were used to analyze the source of heavy metals in the sediments of Yuehai Lake. The result shows that: the average contents of heavy metals such as Cr, Pb, Cu, As, Hg, Cd and Co in the Yuehai Lake Sediment (mg.kg-1) are separately 59.2, 19.3, 27.04, 12.94, 0.16, 0.1, 19.23, both exceeding the background value of heavy metals in the Yellow River Irrigation Area of Yinchuan Plain, the content of Hg and Co elements reached 5.16 times and 2.24 times of the background value. The spatial distribution of heavy metals was significant different, in the whole, there is obvious enrichment in shallow water farms, deep water playgrounds, areas near parks, and bird islands in reed areas, and the other areas of shallow water, water filling ports and drainage openings are all low, and the degree of pollution of various metal elements: Hg>Co>Pb>Cu>Cd>As>Cr. The heavy metal single potential ecological risk is Hg > Cd > Co > As > Pb > Cu >Cr at this stage, among them, Hg element is in a very strong ecological hazard category, and the others are at a slight ecological hazard level. The average of comprehensive potential ecological risks of heavy metals reaches 217, which is a medium ecological hazard category, among them, Hg element exceeds the standard and its contribution rate reaches 76.5%, which led to an increase in the overall ecological risk of the sediment in the Yuehai Lake. Therefore, Hg element pollution Control and source analysis are urgent issues that need to be solved. Except for the Cr and As elements affected by the natural background in the sediments, Hg, Co, Pb, Cu, and Cd elements mainly come from bird droppings, automobile exhaust emissions, artificial farming, construction, and the use of pesticides and fertilizers. There is a significant correlation between the heavy metals in the sediment and the soil particle size composition, increasing the clay content of the sediment soil and reducing the particulate components are likely to enhance the sediment carrying capacity and reduce the risk of release of heavy metal pollutants of the sediment.