Pollution Status and Sedimentary Record of PAHs in the Sediments of Houguan Lake.

In order to investigate the pollution status and sedimentary records of polycyclic aromatic hydrocarbons (PAHs) in the sediments of Houguan Lake in Wuhan, this study collected 7 surface sediment samples and 1 sedimentary column sample in September 2020. The sedimentary column chronological sequence of the Lake was constructed using a combined ²¹⁰Pb and ¹³⁷Cs dating method. The content of 16 optimized PAHs was analyzed using gas chromatography-mass spectrometry (GC-MS), and the source of PAHs was analyzed using characteristic ratio method. The results showed that the average concentration of PAHs in the surface sediment was (247.90±32.01) ng/g, belonging to a moderate pollution level, with 3 and 4 ring PAHs being the main pollutants, and there was no significant difference in spatial distribution. The sedimentation rate of the sedimentary column is 0.73 cm/a, and the collected sedimentary column can reflect the sedimentation process in the past 160 years. The average content of 16 PAHs in the sedimentary column is 56.84 ng/g, indicating a low pollution level. According to the composition characteristics of PAHs, the sedimentation process is divided into four stages. The composition characteristics of PAHs in different stages differ significantly, reflecting the transformation of energy structure in different historical periods. Before the 21st century, there was a significant positive correlation between the content of PAHs and socio-economic indicators such as GDP and permanent population. In recent years, the content of PAHs have been mainly affected by meteorological conditions such as evaporation and temperature, indicating that with China' s emphasis on ecological civilization construction, Wuhan has achieved certain results in ecological environment protection. [ABSTRACT FROM AUTHOR]