History of atmospheric PAHs sedimentation and response to human activities in Bosten Lake in Western China

The contents of 16 kinds of polycyclic aromatic hydrocarbons (PAHs) listed on US EPA’s Priority chemical list in the sediment cores taken from the center of Bosten Lake in Western China were analyzed, and dated with 210 Pb and 137 Cs in order to reconstruct the history of PAHs sedimentation in Bosten Lake in the period of 1945~2018. Pollution sources were quantified and determined with a PMF (positive matrix factorization) model, the zones for pollution sources analyzed with a HYSPLIT (Hybrid Single-Particle Lagrangian Integrated Trajectory) model, and the influencing mechanism of primary parameters of urbanization to the history of PAH sedimentation analyzed using the stochastic influence model (STIRPAT). The research showed the total content of 16 kinds of PAHs was 51.07~583.73ng/g, and that 3~4 rings were dominant components. Over 70 years, variations in total contents of PAHs in sediments have generally been shown by a trend characterized by slow fluctuations, violent fluctuations, and rapid increases. In the 1990s, the total content of PAHs and their components started to show more frequent fluctuating increases, and reached their peak values in 2012. PAHs in the sediments of Bosten Lake originate from fossil fuel source of combustion, petroleum leakage/biomass source of combustion, and traffic source, of which the sources of combustion are their main sources. The primary input trajectory of PAHs pollutants starts from the northwest, passing Bayingol Mongolian Autonomous Prefecture to Bosten Lake. Each 1% increase in the industrial value added of Bayingol Mongolian Autonomous Prefecture will result in 0.5178% increase in the content of PAH. It is a main factor for accumulation of PAHs in the sediments in Bosten Lake.