Distribution and evaluation of heavy metals in sediments of Zhenzhu Bay mangrove wetland in Guangxi
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摘要: 沉积物中的重金属属于持久性污染物,具有富集性、难降解性和毒性,长时间累积会对生态环境和人体健康造成威胁。为研究珍珠湾红树林湿地表层沉积物中的重金属含量分布特征及质量现状,2021年9月在珍珠湾红树林分布区采集13件表层沉积物样品,分析测试重金属含量。结果表明: 与国内其他红树林湿地相比,珍珠湾红树林湿地表层沉积物中的重金属含量处于相对较低水平; 地累积指数法显示大部分表层沉积物样品无重金属污染,仅有2个站位受到Cd和Hg的轻微污染,潜在生态风险指数法表明湾内各站位均为低生态风险; 相关性分析和主成分分析表明,Cd主要受江平江输入和珍珠湾东南部海水养殖的影响,其他元素主要为自然背景的岩石风化沉积,利用主成分-多元线性回归模型对重金属的来源进行解析认为,表明江平江输入的重金属贡献率为57%,海水养殖影响的重金属贡献率为43%。综上所述,珍珠湾红树林湿地整体生态状况良好,但仍需重点关注Cd的输入。Abstract: Heavy metals in sediments belongs to persistent pollutants, with characteristics of enrichment, recalcitrance and toxicity, which would pose a threat to the ecological environment and human safety after long-term accumulation. In order to study the distribution characteristics and quality status of heavy metals in the surface sediments of Zhenzhu Bay mangrove wetland, the authors collected 13 surface sediment samples in the mangrove distribution area of Zhenzhu Bay on September in 2021 to analyze the heavy metal content. The results shows that the content of heavy metals in the surface sediments of Zhenzhu Bay mangrove wetland is relatively low compared with other mangrove wetlands in China. Only some stations showed weak Cd and Hg pollution and most stations wasn‘t plolluted by heavy metals, with two showed weak Cd and Hg pollution according to the geo-accumulation index. and all stations in the bay are at low ecological risk based on potential risk index method. Correlation analysis and principal component analysis show that Cd was mainly affected by the input of Jiangping River and mariculture in the southeast of Zhenzhu Bay, and other elements were mainly affected by the weathering and normal deposition of natural background rocks. The contribution rates of Jiangping River input and Zhenzhu Bay mariculture were 57% and 43% respectively through PCA-MLR model analysis on the heavy metal source. The results show that the overall ecological condition of the Zhenzhu Bay Mangrove Wetland is good, however, it is still necessary to pay attention to the input of Cd.
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Key words:
- Zhenzhu Bay /
- mangrove wetland /
- heavy metals in sediments /
- pollution assessment
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