Biomagnification of polybrominated diphenyl ethers and alternative halogenated flame retardants through food chains of yellowfin tuna (Thunnus albacares) and their prey from the South China Sea and the associated potential health risk.

Polybrominated diphenyl ethers (PBDEs) and their alternative halogenated flame retardants (AHFRs) have gained global attention due to their ubiquitous occurrence, bioaccumulation, and toxic properties. However, the biomagnification of halogenated flame retardants (HFRs), particularly AHFRs, in various food chains is not yet well understood. In this study, yellowfin tuna (Thunnus albacares), along with its prey, flying squid (Sthenoteuthis oualaniensis) and round scad (Decapterus maruadsi), were sampled from the South China Sea (SCS) to investigate the biomagnification potential of PBDEs and AHFRs, including dechlorane plus (DP) and decabromodiphenyl ethane (DBDPE). The results showed that PBDEs were the predominant HFRs detected in all fish samples. However, the levels of PBDEs in the present study were lower than those reported in previous studies, indicating a recent reduction in PBDE contamination in the SCS. The average biomagnification factor (BMF) values for all target HFRs, except for BDE 99 and BDE 183, were in the range of 1.03 to 57.61, suggesting that these compounds were biomagnified from prey fish to predator of yellowfin tuna. In contrast, BDE 99 and BDE 183 were biodiluted in the flying squid-yellowfin tuna food chain. Additionally, the BMF values decreased with the increased log K of PBDEs in these two food chains. Lastly, the average estimated daily intakes of PBDEs, DP, and DBDPE suggest that consuming these marine species is unlikely to pose significant health risks.