Brominated flame retardants (BFRs), including polybrominated diphenyl ethers (PBDEs), tetrabromobisphenol A (TBBPA), and hexabromocyclododecanes (HBCDs), were investigated in bivalve (i.e., oyster (Crassostrea gigas) and mussel (Mytilus coruscus)), sediment, and seawater samples collected from aquaculture areas in South Korea to identify their occurrence, sources, and bioaccumulation. Among the studied chemicals, HBCDs predominated in bivalves and sediment, with concentrations of ND-67.52 ng/g lipid weight and 3.47-168 ng/g dry weight, respectively, while TBBPA was the highest contributor in seawater (ND-2.79 ng/L). Compared with a non-aquaculture area, HBCD and PBDE concentrationswere significantly higher in all matrices in the aquaculture area (Mann-Whitney U test, p < 0.05), suggesting that sourcesmay be located near or associated with the aquaculture areas, such as industrial complexes and expanded polystyrene buoys. Finally, the bioconcentration factor (BCF) and biota-sediment accumulation factor (BSAF) were estimated. Among the studied BFRs, BDE-47 (BCF: 1.70 x 10(6) L/kg; BSAF: 20.92) and alpha-HBCD (BCF: 1.05 x 10(6) L/kg; BSAF: 0.13) showed the highest accumulation potentials in bivalves. (C) 2017 Elsevier B.V. All rights reserved.