State Key Laboratory of Lake Science and Environment Research, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing 210008, China.
State Key Laboratory of Lake Science and Environment Research, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing 210008, China; University of Chinese Academy of Sciences, Beijing 100049, China.
J Hazard Mater. 2021 Feb 5;403:123973. doi: 10.1016/j.jhazmat.2020.123973. Epub 2020 Sep 15.
We examined the riverine transport of polycyclic aromatic hydrocarbons (PAHs) based on their spatial-temporal distributions in water and sediments from the mainstream along the middle and lower Yangtze River. According to the fugacity fraction (ff) estimation, sediments performed as a secondary emission source of two-, three-, and four-ringed PAHs and as a sink for five- and six-ringed congeners, leading to higher ecological and human health risks especially towards the lower reaches. The higher PAH levels observed in the more developed delta and megacities were highly linked to economic parameters. This was further supported by the source apportionment performed using the principal component analysis-multiple linear regression (PCA-MLR) model, which showed major contributions of coal and coke combustions along with vehicle emissions. The spatial-temporal distribution revealed that water runoff was the major contribution to PAHs transport along the middle-lower Yangtze River, whereas a sharp decrease in sediment discharge due to the dam impoundment along the upper reaches would lead to an increase in the catchment retention effect of PAHs. Hence, the biogeochemical processes of PAHs and their impacts on the fragile ecosystems as a consequence of the further modification of the sedimentary system in rivers need to be fully explored.
我们根据长江中下游干流的水质和沉积物中多环芳烃（PAHs）的时空分布，研究了河流输送的多环芳烃。根据逸度分数（ff）的估算，沉积物表现为二、三、四环 PAHs 的二次排放源，也是五、六环同系物的汇，导致下游地区的生态和人类健康风险更高。在三角洲和特大城市这些经济更发达的地区，PAH 水平更高，这与经济参数高度相关。这一点通过主成分分析-多元线性回归（PCA-MLR）模型进行的源解析得到了进一步证实，该模型显示，煤和焦炭燃烧以及车辆排放对 PAHs 的贡献较大。时空分布表明，径流量是沿长江中下游输送 PAHs 的主要因素，而上游大坝蓄水导致的沉积物排放量急剧减少，将增加流域对 PAHs 的截留效应。因此，需要充分探讨 PAHs 的生物地球化学过程及其对脆弱生态系统的影响，因为河流沉积物系统的进一步改变会导致这些影响。
