The phenomena for bioaccumulation and biomagnification of polybrominated diphenyl ethers (PBDEs) were observed in the freshwater food chain of Baiyangdian Lake. The result was achieved through the joint efforts of two CAS research groups by Prof. Mu-Qi Xu at Institute of Zoology and Prof. Bi-Xian Mai at Guangzhou Institute of Geochemistry. It was considered to have great implications on management of persistent organic pollutants (POPs).

The environmental and biological behaviors of PBDEs have been one of the issues in environmental and ecotoxicological research in recent years. Tetra-, Penta-, Hexa- and Hepta-brominated diphenyl ethers have been formally listed in Stockholm Convention by United Nations Environment Programme in May 2009.

Based on the freshwater ecosystem of Baiyangdian Lake, Professor Mu-Qi Xu and his colleagues determined the distribution of PBDEs in various aquatic organisms. The results indicated that nine PBDE congeners (BDE-28, -47, -66, -99, -100, -85, -153, -154, and -183) were detected in zooplankton, benthic invertebrate animals, crustacea, fish (including herbivorous, detritivorous and carnivorous species) and waterfowl. The highest concentration of PBDEs (160 ng/g lipid weight) was observed in the tissues of ricefield eel. BDE-209 was detected in 50% of biota samples, which indicated the bioavailability of BDE209. The compositional profile of PBDE congeners indicated that BDE-47 was the predominant congener in most samples except for river snails and swan mussels. Correlation between lipid-normalized concentrations of PBDEs and trophic levels (TLs) determined by stable isotope nitrogen technologies confirmed that PBDEs were biomagnified in the freshwater food chain. The trophic magnification factors (TMFs) ranged from 1.3 to 2.1 for PBDE congeners, greater than one, indicating the biomagnification potential for the PBDE congeners in the freshwater food chain. The relationship between trophic magnification factors (TMFs) and Log K_ow (octanol–water partition coefficient) indicated that the phenomenon of trophic magnification for lowly brominated congeners was obvious in the freshwater food chain.

To our knowledge, this is the first study to report concentrations and profiles of PBDE congeners in biota fromBaiyangdian Lake, North China. The various concentrations and profiles of PBDEs in aquatic organisms from Baiyangdian Lake indicated different metabolisms of contaminants.

This paper has been published in Environment International (Hu GC, Dai JY, Xu ZC, Luo XJ, Cao H, Wang JS, Mai BX*, Xu MQ*. 2010. Bioaccumulation behavior of polybrominated diphenyl ethers (PBDEs) in the freshwater food chain of Baiyangdian Lake, North China. Environment International 36:309-315). This project was supported by the “National Basic Research Program of China” (973 Program) (No. 2006CB403306) and the National Natural Science Foundation of China (No. 30870311).

Compositional profiles of PBDEs in aquatic organism collected from Baiyangdian Lake, North China (ZPK = zooplankton, RSN = river snail, SWM = swan mussel, SRM = shrimp, CRB = crab, CCA = common carp, CRC = crucian carp, BCA = bighead carp, GCA = grass carp, NSH = northern snakehead, OSF = oriental sheatfish, YCF = yellow catfish, RFE = ricefield eel, LCH = loach, TUR = turtle, and DUC = duck)

Relationship of major PBDE congeners (pg/g lw) in the Baiyangdian Lake food chain and TLs calculated from d15N values. Vertical and horizontal bars represent standard errors for mean values in each species. ZPK = zooplankton, SRM = shrimp, CRB = crab, RSN = river snail, SWM = swan mussel, CCA = common carp, CRC = crucian carp, GCA = grass carp, BCA = bighead carp, NSH = northern snakehead, YCF = yellow catfish, LCH = loach, RFE = ricefield eel. The oriental sheatfish, turtle, and duck samples were purposely omitted from the plot.