大亚湾海域重金属空间分布特征及其来源分析

Spatial Distribution Characteristics of Heavy Metals in the Daya Bay Waters and Analysis of Their Sources

摘要: 2023年秋季对大亚湾海水及表层沉积物中铜(Cu)、铅(Pb)、镉(Cd)、铬(Cr)、锌(Zn)、汞(Hg)含量进行调查，分析各重金属元素含量分布特征并进行质量评价，同时采用皮尔逊相关系数(Pearson)、层次聚类(Hierarchical Clustering)等源解析模型分析大亚湾海域污染源。结果表明，海水中6种元素平均含量由大到小分别为Zn > Cu > Pb > Cr > Hg，沉积物平均含量由大到小分别为Zn > Pb > Cr > Cu > Cd > Hg；2023年秋季海水重金属整体呈现沿岸高浓度、离海岸浓度低的特点，表层沉积物整体呈现湾顶重金属含量较高、湾底浓度低的特点，其中湾顶重金属主要来源于工业活动，湾顶西侧还与交通运输业有关，东部主要源于人类活动、船舶尾气等；利用算术均值多因子指数法、地累积指数法和潜在生态风险指数检测出该海域目前处于清洁状态，水质良好，属于轻微潜在生态风险等级；Pearson分析与聚类分析结果表明OC与Cd、Zn、Hg具有较强的相关性，主要污染来源相似。

Abstract: In autumn 2023, the content of copper (Cu), lead (Pb), cadmium (Cd), chromium (Cr), zinc (Zn), and mercury (Hg) in seawater and surface sediments of Daya Bay was investigated. The distribution characteristics of these heavy metals were analysed, and a quality assessment was conducted. Source analysis models such as Pearson correlation coefficients and hierarchical clustering were used to analyse pollution sources in the Daya Bay area. The results showed that the average concentrations of the six elements in seawater ranked from highest to lowest as Zn > Cu > Pb > Cr > Hg, while in sediments they ranked as Zn > Pb > Cr > Cu > Cd > Hg. In autumn 2023, heavy metals in seawater displayed higher concentrations near the coast and lower concentrations offshore. Surface sediments showed higher concentrations at the bay head and lower concentrations at the bay bottom. Heavy metals at the bay head mainly originated from industrial activities, with the west side also linked to transport activities. In eastern Daya Bay, pollution mainly arose from human activities and ship exhaust emissions. Arithmetic mean multi-factor index, geoaccumulation index, and potential ecological risk index assessments indicated that the area is currently clean, with good water quality, corresponding to a slight potential ecological risk level. Pearson correlation and cluster analyses demonstrated strong correlations between OC and Cd, Zn, and Hg, and the main sources of pollution are similar.