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    闽江口表层沉积物中多环芳烃的分布特征、来源解析及生态风险评估

    Distribution, sources and ecological risks of polycyclic aromatic hydrocarbons(PAHs)in surface sediment of Minjiang estuary

    • 摘要: 多环芳烃(PAHs)作为一种广泛存在于环境中的持久性有机污染物,其在河口地区沉积物中的高暴露水平对河口生态系统构成了潜在的生态风险。本研究通过采集闽江口近岸40 件表层沉积物样品,运用统计分析、比值法及主成分分析等方法对沉积物中 15 种 PAHs 的污染来源进行解析,同时采用风险熵值法对其生态风险进行评估,旨在探究闽江口近岸表层沉积物中 PAHs 的分布特征、污染来源及其生态风险状况。研究结果显示:闽江口表层沉积物中PAHs的总含量为9.47~197.54 ng/g,平均值为89.91 ng/g,主要以4~5环的高环PAHs为主,其中4环PAHs的占比最高;和国内外其他河口区域比较,闽江口表层沉积物中PAHs处于相对较低污染水平;在不同类型的沉积物中,黏土质粉砂的PAHs平均含量最高,且4~5环PAHs的占比亦最高;研究区内PAHs的污染主要来自燃烧源,包括煤炭、生物质和石油的燃烧;生态风险评估显示,闽江口表层沉积物中部分单体PAHs存在中等生态风险,其中BbF(苯并a蒽)达到了严重生态风险水平,因此亟需加强相关管理措施。本研究结果可为闽江口海洋环境保护提供科学依据。

       

      Abstract: As a kind of persistent organic pollutant widely existing in the environment, PAHs (Polycyclic aromatic hydrocarbons) in sediments is highly exposed in estuaries, posing a potential ecological risk to the estuarine environment. In order to study the distribution characteristics, sources and ecological risk of the surface sediments in Minjiang estuary, this study collected 40 surface sediment samples in the area, determined 15 PAHs sources by statistical analysis, ratio method and principal component analysis, and assessed their ecological risk with risk entropy value. The results showed that the total content of PAHs ranged from 9.47 to 197.54 ng/g, with a mean value of 89.91 ng/g. The main components were 4-5 ring PAHs, with the 4-ring PAHs accounting for the highest proportion, but this area remains lower polluted in comparison with other estuaries. Among different types of sediments, clayey chalk has the highest average PAHs content and the biggest proportion of 4-5 ring PAHs. The sediments’ PAHs mainly originated from combustion sources, including coal, biomass and oil combustion. The ecological risk assessment indicates that some of the individual PAHs in the surface sediments of the Minjiang estuary are at moderate ecological risk, with BbF reaching the severe level of ecological risk. Therefore, it is urgent to strengthen relative control measure. The results of the study can provide a scientific basis for marine environmental protection in the Minjiang estuary.

       

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