Coastal oceans, serving as transitional zones between land and sea, possess unique geographical features and complex hydrological conditions, acting as regional reservoirs and crucial transport pathways for anthropogenic pollutants such as polycyclic aromatic compounds (PACs), per- and polyfluoroalkyl substances (PFASs) to the open ocean. This study comprehensively investigates polycyclic aromatic hydrocarbons (PAHs) and their alkylated, oxygenated and nitrated derivatives (A-PAHs, O-PAHs and N-PAHs), traditional perfluoroalkyl carboxylic and sulphonic acids (PFCAs and PFSAs) and emerging perfluoroalkyl ether carboxylic and sulfonic acids (PFECAs and PFESAs), fluorotelomer sulfonates (FTSAs) in seawater columns and surface sediments of the East China Sea. The key hydrological and biogeochemical parameters and metagenomic information are also included to examine the potential sources and essential ocean processes. Our results suggested the importance of terrestrial inputs for PAHs, A-PAHs and all PFASs investigated, with coastal currents regulating their horizontal transport and fronts acting as barriers. In contrast, O-PAHs and N-PAHs are primarily shaped by secondary transformations within specific water masses. All PACs are vertically influenced by bottom-up processes, where upwelling-induced sediment resuspension promotes their subsequent release and secondary transformation. While the bottom-up control is rather weaker for either traditional or emerging PFASs. The impact of the top-down biological pump on PACs and PFASs is limited by low wintertime primary productivity. Metagenomic analysis highlights the role of microbial degradation in PAC removal, with enhanced microbial diversity driven by terrigenous advection and sediment resuspension. The methodologies and findings of this research provide valuable insights into PAC and PFAS cycling in coastal oceans worldwide.

coastal ocean,polycyclic aromatic compounds,emerging PFASs,ocean process