Identifications and seasonal variations of sources of polycyclic aromatic hydrocarbons (PAHs) in the Yangtze River Estuary, China

In this study, positive matrix factorization models (PMFx) were used to analyze the sources of sedimentary PAHs in Yangtze River Estuary (YRE) using 120 data samples from 30 sites collected over four seasons. Three sources were defined for the PAHs: coal and gasoline combustion was the dominant source, accounting for approximately 50%; coke plant emissions and wood or grass combustion each contributed approximately 25%. The coal tar origin was the major source in summer; wood or grass combustion dominated in autumn; coal combustion was the primary source of PAHs in spring and winter. More than 90% of the coke plant emissions were from summer, while pollutants from wood or grass combustion were discharged primarily in autumn. These three sources distributed in different primary regions, the spatial patterns of coal combustion presented an increasing trend in the seaward direction.