An increasing number of brominated flame retardants and other brominated substances are being reported in organisms and sediments from the Laurentian Great Lakes basin. Recently, we characterized and confirmed the presence of six congeners of novel methoxylated polybrominated diphenoxybenzene (MeO-PBDPB) in the Great Lakes herring gulls, where four congeners contain five bromines and the other two contain four and six bromines, respectively. Optimized, semi-quantitative analysis revealed sum concentrations of the MeO-PBDBP congeners (?MeO-PBDPBs) ranged from <0.2 � 39.1 ng/g wet weight in pooled egg homogenates (collected in 2009) from fourteen herring gull colony sites across the Great Lakes, with the highest concentration being for Channel-Shelter Island in Saginaw Bay (Lake Huron). Temporal analyses for the time period of 1982 � 2009 indicated that the ?MeO-PBDPBs concentrations peaked around early 2000's and then slightly decreased over time in the Channel-Shelter Island egg pool homogenates. However, concentrations generally increased in the eggs from Fighting Island (Lake Erie), Toronto Harbour (Lake Ontario) and Big Sister Island (Lake Michigan), whereas the levels in Agawa Rocks (Lake Superior) declined. To our knowledge, there are no published reports on the environmental presence and sources of MeO-PBDPBs. The discovery of MeO-PBDPBs in Great Lakes herring gull eggs indicates their substantial bioaccumulation potential, and raises concerns about their origin, environmental behavior and influences on wildlife and environmental health. We hypothesize that these MeO-PBDPBs are degradation products of the polybrominated diphenoxybenzenes, e.g., tetradecabromodiphenoxybenzene or TDBDPB. Our photolytic experiments demonstrated that TDBDPB could undergo stepwise reductive debromination that follows first-order kinetic degradation models when dissolved in the solvents tetraphydrofuran, methanol or n-hexane and exposed to UV or natural sunlight radiation. The most abundant degradation products produced from natural sunlight radiation were Br4- to Br7-PBDPBs. Neat technical TDBDPB powder exposed to UV-B and �C radiation also produced less brominated products.

Spatial and temporal trends and possible sources of methoxylated polybrominated diphenoxybenzenes in herring gull eggs from the Laurentian Great Lakes of North America

246th National Meeting (2013)

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