Polycyclic aromatic hydrocarbons in freshwater organisms from Hubei, Central China: health risk assessment and source identification

Polycyclic aromatic hydrocarbons (PAHs) can be absorbed and accumulated in aquatic organisms, posing a threat to human health through the food chain. However, the concentration, composition, potential source and health risks of PAHs in freshwater organisms remain largely unknown. This study aimed to investigate the presence of PAHs in freshwater organisms in Hubei, Central China. The levels of 16 PAHs in the studied freshwater organisms ranged from 4.31 to 49.60 ng g^-1, with an average value of 38.40 ng g^-1. Comprising 75-81% of the total, 3-4 ring PAHs were the primary components in freshwater organisms, with an average ratio of 77.3%. Molecular diagnostic ratios (MDR) and principal component analysis (PCA) successfully identified combustion-related contamination as the major source of PAHs in these organisms. The incremental lifetime cancer risk (ILCR) values associated with PAH exposure were higher for crabs and fishes and were greater for children than for adults, suggesting potential carcinogenic risks to humans <i>via</i> the consumption of freshwater organisms. A comparative analysis of PAH concentrations in marine and freshwater organisms showed that the levels of 16 PAHs in marine organisms were more than twice as high as those in freshwater organisms, indicating differing behaviors of PAHs in marine and freshwater environments. Overall, this study significantly enhances the understanding on PAH accumulation in freshwater organisms and provides valuable insights for preventing and controlling PAH pollution in freshwater aquatic products.