Bioaccumulation, trophic transfer and suspect screening for methoxylated brominated compounds in a tropical marine...

Methoxylated brominated compounds are widespread in the marine environment, yet their marine biogeochemical behavior remains poorly characterized. Herein, bioaccumulation and biomagnification of methoxylated polybrominated diphenyl ethers (MeO-PBDEs) and suspect screening for other methoxylated brominated compounds were explored in marine biota collected from the Xisha Islands, South China Sea. The concentrations of ΣMeO-PBDEs in marine fish and seabirds ranged from 2.87-17919 and 73.3-557 ng/g lipid weight (lw), with mean values of 944 ± 267 and 265 ± 82.8 ng/g lw, respectively. MeO-PBDEs in marine fish were mainly derived from natural biosynthesis. The average biota-sediment accumulation factors of 2'-MeO-BDE68, 6-MeO-BDE47, 4'-MeO-BDE49, 4-MeO-BDE42 and 5-MeO-BDE47 were all higher than 1, confirming sediment-derived bioaccumulation of these MeO-PBDE congeners in demersal fish. The biomagnification factor values of 6-MeO-BDE137 and 3-MeO-BDE47 based on quantitative fatty acid signature analysis were both greater than 1 in three seabird species, indicating high biomagnification capacities of these two MeO-PBDEs in seabirds. 6-MeO-BDE47, 6-MeO-BDE137 and 3-MeO-BDE47 showed significant trophic magnification, indicating that accumulation of the three MeO-PBDEs increased with trophic levels in the tropical marine food web. Seven new methoxylated brominated compounds including one Me-MeO-triBDE, three diMeO-PBDEs, two chlorinated diMeO-PBDEs and one diMeO-tetraBB were identified in marine biota by suspect screening. This study highlights bioaccumulation and trophic transfer of MeO-PBDEs in the tropical marine food web and the ecological risks of seven novel methoxylated brominated compounds in marine biota are needed to further evaluate.