广西北海铁山港湾表层沉积物污染物分布特征及其影响因素分析

Characteristics of pollutants distribution in surface sediments of Tieshangang bay, Beihai, Guangxi, and their influencing factors

关键词:  铁山港湾  沉积物  污染特征  主成分分析  聚类分析

Key words:  Tieshangang bay  Sediment  Pollution Characteristics  Principal Component Analysis  Cluster Analysis

摘要:

广西北海铁山港湾拥有红树林、海草床等典型海洋生态系统，具有较高的生态价值，同时易受人类开发活动影响。为了解铁山港湾表层沉积物主要污染物分布特征及其影响因素，本研究以2021 年春、秋季铁山港湾环境质量调查为基础，分析铁山港湾表层沉积物中Hg、As、Cu、Pb、Zn、Cd、石油类、硫化物和有机碳等污染物含量、空间分布特征和污染程度，采用相关性分析、主成分分析和聚类分析等方法探讨影响污染物空间分布的因素。结果显示，铁山港湾海洋沉积物质量总体处于优良状态，受污染程度低，其中重金属未受污染，重金属潜在生态风险较低。铁山港湾沉积物中石油类、有机碳和硫化物具有显著正相关性，Cu、Zn和Pb具有显著正相关性，Hg和Cd具有显著正相关性。铁山港湾沉积物污染物含量可以概括为两个主成分，两个主成分可累计解释总方差的64.26%。聚类分析结果显示铁山港沉积物中污染物可分为四簇，第一簇为有机碳、硫化物和石油类，第二簇为As，第三簇为Cu、Zn和Pb，第四簇为Hg和Cd。铁山港湾沉积物中污染物分布除受地质背景和人类活动的影响外，同时也受海湾的水动力条件影响。铁山港湾夏秋季较强的水动力能促进沉积物中污染物向外输运，使得春秋两季污染物在空间分布上存在一定的差异。

Abstract:

Tieshangang bay in Guangxi Beihai has typical marine ecosystems such as mangrove forests and seagrass beds, which are of high ecological value and at the same time susceptible to human development activities.In order to understand the distribution characteristics of major pollutants and their influencing factors in the surface sediments of Tieshangang bay, Beihai, this study analysed the content, spatial distribution characteristics and the degree of contamination of pollutants such as Hg, As, Cu, Pb, Zn, Cd, petroleum, sulfide, and organic carbon in the surface sediments of Tieshangang bay, based on the environmental quality surveys of Tieshangang bay in the spring and autumn of 2021. Correlation analysis, principal component analysis and cluster analysis were used to explore the factors affecting the spatial distribution of pollutants. The results showed that the quality of marine sediments in Tieshangang bay was generally excellent, with a low degree of contamination, in which heavy metals were not contaminated and the potential ecological risk of heavy metals was low. Petroleum, organic carbon and sulfide in the sediments of Tieshangang bay had significant positive correlations, Cu, Zn and Pb had significant positive correlations, and Hg and Cd had significant positive correlations. The pollutant content of sediments in Tieshangang bay can be summarised into two principal components, which can cumulatively explain 64.26% of the total variance. The results of cluster analysis showed that the pollutants in the sediments of Tieshan Harbour could be divided into four clusters, the first one was organic carbon, sulfide and petroleum, the second one was As, the third one was Cu, Zn and Pb, and the fourth one was Hg and Cd. The distribution of the pollutants in the sediments of Tieshangang bay was not only affected by the geological background and the human activities, but also by the hydrodynamic conditions of the bay. Stronger hydrodynamics in Tieshangang bay in summer and autumn can promote the outward transport of pollutants in the sediments, which makes the spatial distribution of pollutants in spring and autumn have some differences.