Emerging organic contaminants (EOCs), including per- and polyfluoroalkyl substances (PFASs), polybrominated diphenyl ethers (PBDEs), polycyclic aromatic hydrocarbons (PAHs), and antibiotics, persist in China's surface seawater, yet their nationwide occurrence and community-level impacts remain unclear. We integrated a systematic review (125 studies) with laboratory bioassays and field surveys to screen priority EOCs, identify drivers, and assess impacts on phytoplankton. Spatially, prevalent contaminants included perfluorooctanoic acid (PFOA) and its short-chain alternatives, naphthalene (Nap), tetrabromodiphenyl ether (BDE-47), decabromodiphenyl ether (BDE-209), oxytetracycline (OTC), and norfloxacin. EOC composition varied among the four seas. Temporally, PFASs and PBDEs declined (driven by regulations and substitutes) PAHs showed a fall-and-rise pattern (linked to energy shifts), while antibiotics kept rising (from mariculture). Under the lenient risk scenario, several PAHs showed 27-38% high-risk exceedance; OTC and BDE-47 had > 10% medium-risk, and PFOA had 3% medium-risk. PFAS distributions correlated with waste treatment and sewage volume, whereas PAHs were driven by direct marine pollution discharge and industrial intensity. Multi-species toxicity tests ranked BDE-47 and sulfamethoxazole as highly toxic; Nap, acenaphthylene and BDE-209 as moderately toxic. In Laizhou Bay, field measurements detected Nap (101.0 ng/L) and PFOA (91.3 ng/L); Nap, together with dissolved oxygen and pH, drove phytoplankton community. Co-culture experiments showed that environmental concentrations did not alter interspecific competition, but elevated exposures did. This work links EOC exposure to regulatory effectiveness and ecological impacts in Chinese seawater, highlights phytoplankton vulnerability, and supports targeted management: accelerating PFAS alternatives, promoting green industrial transition and controlling aquaculture antibiotics, with priority on the Bohai Sea.
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