Effects of urbanization on the distribution of polycyclic aromatic hydrocarbons in China's estuarine rivers

Estuarine rivers are the primary medium for transporting pollutants from human activities to the ocean. Poly cyclic aromatic hydrocarbons (PAHs) have substantial toxicity and pose a significant risk to ecosystem and human health. However, the influences of urbanization on their distribution, particularly in China where urbanization is occurring rapidly, remain unclear. This study took three coastal economic circles of China as research areas, and investigated PAHs (16 species) in the estuarine river water. 95.9% of the sampling sites demonstrated moderate PAHs pollution and moderate ecological risk. Coal and petroleum combustion was the primary source of PAHs, but the source composition varied among the regions. Air pollution caused by energy emissions, particularly carbon emissions, has a critical and differential effect on PAHs distribution and deposition. With the increasing use of clean energy, PAHs emissions have been gradually reduced, which provides an effective option for PAHs reduction in a rapidly urbanizing coastal region.

Automated summary

Estuarine rivers play a crucial role in transporting pollutants from human activities, such as poly cyclic aromatic hydrocarbons (PAHs), to the ocean. This study investigated the distribution of PAHs in estuarine river water in three coastal economic circles of China. The results showed moderate levels of PAHs pollution and ecological risk. Coal and petroleum combustion were identified as the primary sources of PAHs, with regional variations in source composition. Air pollution caused by energy emissions, particularly carbon emissions, had a significant and differential impact on PAHs distribution and deposition. The increasing use of clean energy has led to a gradual reduction in PAHs emissions, providing an effective option for reducing PAHs in rapidly urbanizing coastal regions.