Disparities in bioaccumulation of chlorinated organic pollutants in O. bartramii and seawater from the Northwest Pacific Ocean: Compound - specific mechanisms and health risks.

Chlorinated organic pollutants (COPs), including organochlorine pesticides (OCPs) and polychlorinated biphenyls (PCBs), persist in marine ecosystems despite global restrictions, posing risks to both organisms and human health. This study systematically investigated the bioaccumulation of 24 COPs in seawater and tissues (muscle, stomach, digestive gland) of the neon flying squid (Ommastrephes bartramii) from the Northwest Pacific Ocean. In O. bartramii, ∑OCPs (8.78-353.72 ng g-1 lw, 78.77 ng g-1 lw) exceeded ∑PCBs (2.50-168.25 ng g-1 lw, 31.59 ng g-1 lw), especially in the digestive gland, while in seawater, ∑PCBs (131.67-445.27 pg L-1, 282.71 pg L-1) surpassed ∑OCPs (40.92-98.41 pg L-1, 57.67 pg L-1). Principal component analysis (PCA) and isomer ratios demonstrated distinct pollutant profiles between seawater and tissues, reflecting fundamentally divergent pollution sources and environmental behaviors mediated by biological metabolism and enrichment processes. Bioaccumulation factors (BAFs) for β - HCH, γ - HCH and α - chlordane far exceeded previous reports, suggesting distinct sources or accumulation. Muscle and digestive gland held over 90 % of the total load, acting as main storage sites. Health risk assessment confirmed the safety of O. bartramii consumption, with carcinogenic risk indices (CRI = 0-1.8 × 10-5) and exposure risk indices (ERI = 0-0.45) below thresholds. These findings enhance understanding of COP bioaccumulation mechanisms and inform policies for global marine pollution control.