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

Considerable debate surrounds the sources of oxygenated polybrominated diphenyl ethers (O-PBDEs) in wildlife as to whether they are naturally produced or result from anthropogenic industrial activities. Natural radiocarbon (¹⁴C) abundance has proven to be a powerful tool to address this problem as recently biosynthesized compounds contain contemporary (i.e. modern) amounts of atmospheric radiocarbon; whereas industrial chemicals, mostly produced from fossil fuels, contain no detectable ¹⁴C. However, few compounds isolated from organisms have been analyzed for their radiocarbon content. To provide a baseline, we analyzed the ¹⁴C content of four O-PBDEs. These compounds, 6-OH-BDE47, 2′-OH-BDE68, 2′,6-diOH-BDE159, and a recently identified compound, 2′-MeO-6-OH-BDE120, were isolated from the tropical marine sponges Dysidea granulosa and Lendenfeldia dendyi. The modern radiocarbon content of their chemical structures (i.e. diphenyl ethers, C₁₂H₂₂O) indicates that they are naturally produced. This adds to a growing baseline on, at least, the sources of these unusual compounds.     

Brominated flame retardants and organochlorine contaminants in winter flounder, harp and hooded seals, and North Atlantic right whales from the Northwest Atlantic Ocean

Various brominated flame retardants (BFRs), including polybrominated diphenyl ethers (PBDEs) and current-use, non-PBDE BFRs, as well as organochlorine (OC) pesticides and polychlorinated biphenyls (PCBs), were measured in winter flounder, harp and hooded seals, and North Atlantic right whales from the Eastern United States and Canada. The concentrations of PBDEs in winter flounder and right whales were similar in magnitude to the levels of PCBs, which was unlike the pattern observed in seals. In these marine mammals, the levels of PBDEs were orders of magnitude lower than the levels of OCs and PCBs detected. Evidence existed for the accumulation of methoxylated (MeO)-PBDEs of natural origin in seals and right whales. Current-use, non-PBDE BFRs (including hexabromocyclododecane, pentabromoethylbenzene, hexabromobenzene, and pentabromotoluene) were detected in winter flounder and marine mammals. Future research should focus on monitoring PBDEs, current-use, non-PBDE BFRs, and MeO-BDEs of natural origin in marine organisms from Massachusetts and Cape Cod Bays.