Marine mammals are important sentinel species for assessing persistent organic pollutant (POP) contamination in marine ecosystems because of their long lifespans, high trophic positions, and large lipid reserves. This study investigated target and unknown POPs in cetaceans and pinnipeds from Korean coastal waters. Target POPs were quantitatively analyzed in multiple tissues and organs, while gas chromatography–time-of-flight mass spectrometry (GC-TOF/MS)-based suspect and non-target screening was separately applied to the same extracts to explore additional POPs beyond the routine target list.
Tissues and organs, including blubber, melon, brain, muscle, liver, lung, intestine, kidney, heart, and stomach, were collected from stranded or by-caught marine mammals. Target POPs, including polychlorinated biphenyls (PCBs), organochlorine pesticides (OCPs), chlorobenzenes (CLBz), and polychlorinated naphthalenes (PCNs), were analyzed to evaluate species-specific accumulation, tissue distribution, and total body burden. Selected compounds detected by suspect and non-target screening were semi-quantitatively estimated using appropriate reference or surrogate standards when applicable.
Among the target POPs, DDTs and PCBs were predominant in most species, indicating the continued persistence and biomagnification of legacy chlorinated contaminants in Korean coastal food webs. Contaminant levels and profiles varied among species and tissues, reflecting differences in habitat, feeding ecology, age, lipid content, and metabolic capacity. Blubber was the major storage tissue and contributed most to the total body burden, whereas measurable levels in liver, kidney, muscle, and other organs suggested redistribution and internal exposure beyond blubber.
The suspect and non-target profiles were generally consistent with the target results, showing more complex chemical patterns in species with elevated DDT and PCB burdens. Additional PCB congeners not included in the routine target list were identified, suggesting that conventional target analysis may underestimate total PCB exposure. Semi-quantitative concentrations of these non-target PCBs showed positive correlations with major target PCB congeners. These results demonstrate that target analysis captures the dominant contaminant burden but may not fully represent the diversity of POP exposure. These findings highlight the need for integrated monitoring, combining target and non-target analyses, to better assess and manage the risks of POPs to marine mammals.

Acknowledgments: This study was supported by the Korea Institute of Marine Science and Technology Promotion, funded by the Ministry of Oceans and Fisheries, Korea (RS-2024-00417889), and by the National Research Foundation of Korea grant funded by the Korea government (MSIT) (RS-2025-02263830).