Decadal monitoring of trace organic contaminants in common carp from the Han and Yeongsan Rivers

Emerging contaminants in freshwater fish pose ecological and human health risks, yet long-term tissue-residue data for fish muscle remain scarce. This study assessed the decadal accumulation of trace organic contaminants in common carp (Cyprinus carpio) from two major Korean rivers, the Han and Yeongsan Rivers. Sixty-nine archived muscle samples collected from 2012 to 2021 were analyzed by liquid chromatography–high-resolution mass spectrometry (LC-HRMS) using a target screening approach covering 81 compounds. Of these, 15 compounds were detected above the limit of quantification, with pharmaceuticals being the predominant group. Hydroxychloroquine showed the highest concentration and detection frequency in both rivers, although data on its bioaccumulation remain limited and warrant further investigation. In contrast, PFOS and pyroquilon exhibited significant decreasing temporal trends, temporally consistent with changes in chemical usage patterns and environmental regulations, although causality cannot be established. The two rivers displayed distinct contamination profiles: the Han River was dominated by urbanization-derived pharmaceuticals, whereas the Yeongsan River reflected the influence of legacy PFOS associated with industrial activity. These findings demonstrate the value of long-term biological archives and LC-HRMS-based target screening for tracking trace contaminant accumulation and identifying priority compounds for aquatic ecosystem management.