Contemporary 14C radiocarbon levels of oxygenated polybrominated diphenyl ethers (O-PBDEs) isolated in sponge-cyanobacteria associations

► O-PBDEs in the marine environment could have both natural and anthropogenic origin. ► Molecular-level 14C is measured by accelerated mass spectrometry. ► Industrial products, derived from fossil sources, are radiocarbon 14C-free. ► O-PBDEs compounds from marine sponges show modern levels of 14C. ► Some species could produce O-PBDEs rather than being biotransformation from industrial PBDEs.