我国三大河口沉积多环芳烃及其衍生物的赋存特征

Occurrence of polycyclic aromatic hydrocarbons and their derivatives in the sediment of the three major estuaries in China

  • 摘要: 多环芳烃(polycyclic aromatic compounds,PAHs)是河口环境中存在最为广泛的一类有机污染物,目前针对PAHs环境地球化学的研究大都围绕少数优先控制PAHs展开,这对于理解其环境行为和生态风险存在较大局限性和不确定性。为了全面探究我国河口环境中PAHs类有机污染物的赋存特征,本研究以黄河口、长江口和珠江口三大典型河口表层沉积物为例,基于全二维气相色谱−飞行时间质谱建立了包含81种母体PAHs及其衍生物(包括20种未被取代的母体PAHs、11种含氧PAHs、9种氧杂环PAHs、3种硫杂环PAHs和38种烷基化PAHs等类别)的监测清单。结果表明,38种烷基化PAHs是三大河口沉积物中最主要的组分,在81种PAHs清单中的平均占比超过了50%,而16种母体PAHs所占的比例平均约为10%。虽然三大河口之间PAHs及其衍生物的总含量并不存在统计学上的显著性差异,但是不同类型的PAHs及其衍生物之间的相关关系并不一致,这可能表明三大河口不同的PAHs来源和沉积特征。以81种PAHs作为清单的生态风险评估结果相较于16种优控母体PAHs高出4倍以上,这表明基于扩大的PAHs及其衍生物的监测清单进行生态风险评估是非常有必要的。本研究思路有助于正确评估沉积物或其他水环境中芳香族有机污染物的生态风险。

     

    Abstract: Polycyclic aromatic hydrocarbons (PAHs) are the most widespread organic pollutants in estuarine environment. Existing research on the environmental geochemistry of PAHs mostly focuses on a few priority controlled PAHs, which has significant limitations and uncertainties in understanding their environmental behavior and ecological risks. To comprehensively explore the occurrence characteristics of polycyclic aromatic compounds in estuarine environment in China, this study takes surface sediments of the three typical estuarine including Huanghe Estuary, Changjiang Estuary and Zhujiang Estuary as examples to establish a monitoring list of 81 PAHs and their derivatives (including 20 unsubstituted parent PAHs, 11 oxygen-containing PAHs, 9 oxygen-heterocyclic PAHs, 3 sulfur-heterocyclic PAHs and 38 alkylated PAHs) by using of two-dimensional gas chromatograph coupled with time-of-flight mass spectrometry. The results show that 38 alkylated PAHs are the most important components in the three estuarine sediments, The average proportion in the list of 81 PAHs exceeds 50%, but the proportion of 16 priority controlled PAHs is only about 10% on average. Although there was no statistically significant difference in the total content of PAHs and their derivatives among the three estuaries, the correlation between the different types of PAHs and their derivatives was inconsistent, which may indicate the different characteristics of PAH sources and sedimentary in the three estuaries. The results of ecological risk assessment using 81 PAHs as a list are about 4 times higher than those of 16 priority controlled PAHs, which means that it is necessary to expand the monitoring list of PAHs and their derivatives for ecological risk assessment. This research approach helps to correctly assess the ecological risk of aromatic organic pollutants in sediments or other aquatic environments.

     

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