Occurrence, exposure risk, and source tracing of polybrominated diphenyl ethers (PBDEs) in farmed freshwater aquatic products from the Yangtze River area

Polybrominated diphenyl ethers (PBDEs) are a typical group of persistent organic pollutants (POPs) widely present in the environmental media and aquatic products. However, knowledge about the content and source of PBDEs in aquatic products from freshwater farms is lacking. Herein, a sensitive and robust method for the detection of 25 PBDE congeners was established. The concentrations of PBDEs were analyzed in aquatic products (fish, shrimp, and crab), along with their feed, water, and sediment collected from the lower reaches of the Yangtze River. Results showed the mean concentration of ∑PBDEs in crab (210.2 pg g −1 ww) was significantly higher than in shrimp (33.3 pg g −1 ww), crucian carp (33.2 pg g −1 ww), and black carp (24.3 pg g −1 ww), indicating a higher bioaccumulation rate of PBDEs in crab than the others. The highest concentrations of PBDEs were found in crab hepatopancreas, accounting for over 77.6% of the relative body burdens (RBBs) of these contaminants. The content of PBDE congeners in different aquatic products exhibits interspecies variation, whereas similar patterns are observed within the same aquatic products across different bases. No obvious dietary risk was found for all collected aquatic products under the two assessment strategies. Commercial feed was the main pollution route for all the farming bases and, in farming bases with snails and frozen fish, the contribution of these animal baits is also non-negligible. This study comprehensively elucidates the occurrence, risk and source of PBDEs contamination in farmed freshwater aquatic products, offering significant insights into exposure risks and the development of prevention strategies, which are crucial for ensuring the safety of aquatic products.