Bioaccumulation and Metabolism of Polybrominated Diphenyl Ethers in Carp (Cyprinus carpio) in a Water/Sediment Microcosm: Important Role of Particulate Matter Exposure

Abstract

Microcosms were built up to simulate a pond system with polybrominated diphenyl ether (PBDE) contaminated sediment and bioorganisms. The microcosms were divided into groups A and B. In group A, both benthic invertebrates (tubificid worms) and carp (Cyprinu carpio) were added, while in group B, only fish were added. After exposure for 20 d, the fish were sampled (exposure I). A net was fixed in the microcosms, and new fish were added (exposure II). These fish were prohibited from contacting the sediment by the net, and the accumulation and depuration of PBDEs in the fish were investigated. Among 11 monitored PBDE congeners (BDE-28, BDE-47, BDE-99, BDE-100, BDE-153, BDE-154, BDE-183, BDE-206, BDE-207, BDE-208, and BDE-209), only 5 congeners (BDE-28, BDE-47, BDE-100, BDE-153, and BDE-154) were detected in the carp fillets and liver. BDE-99 and BDE-183 were not detected in the fish because of the efficient metabolic debromination in carp tissues. The uptake of PBDEs in exposure I was significantly higher/faster than that in exposure II, since the fish in exposure I had an opportunity to take in more of the highly contaminated particles. The uptake kinetics (k(s)) and elimination (k(e)) rate coefficients showed a general trend of decreasing with increasing log K(ow). No significant difference was observed in uptake/depuration kinetics between groups A and B, indicating that the tubificids' reworking does not affect the bioaccumulation of sediment-associated PBDEs in fish significantly. All the PBDE congeners, including nona- and deca-BDEs, were bioaccumulated in the tubificid worms. The PBDE concentrations in the worms were significantly higher than those in the fish, and the congener profile of the sevem major congeners (BDE-28, BDE-47, BDE-99, BDE-100, BDE-153, BDE-154, and BDE-183) was distinctly different from that of fish tissues. The biota-sediment accumulation factors in the worms ranged from 0.01 to 5.89 and declined with increasing bromination and log K(ow.).

Bioaccumulation of Polybrominated Diphenyl Ethers by Tubifex Tubifex

“…The BSAF for tri-to hexa-BDEs varied between 5.95 and 2.69 (on average 4.34) and in the hepta-to deca-homologues between 2.14 and 0.13 (on average 0.95). Similar conclusions were drawn by Tian et al 32 In the 80-day microcosm study the BSAF for tri-to hepta-BDEs varied between 5.89 and 1.09 (on average 3.46), while a distinctive bioaccumulation gap appeared between the octa-(BSAF of 0.99) and nona-to deca-homologues (BSAF in the range 0.05-0.01, on average 0.3).…”

“…These results lead to the conclusion that the accumulated BDEs undergo only a little or no transformation in the oligochaetes, which is particularly relevant in studies of the lower trophic levels of aquatic as well as of terrestrial ecosystems. The difference between the bioaccumulation of BDEs in sediment-dwelling oligochaetes (T. tubifex) and in fish on the higher tropic level was demonstrated in a water/sediment microcosm system by Tian et al 32 The simple digestive tract and metabolic system of the oligochaetes mean a relatively low metabolic capacity to debrominate BDEs. At the end of 80 days of exposure to the tri-, tetra-, penta-, hexa-, hepta-, and nona-BDE homologues, all 11 monitored BDE congeners could be quantified in worms, while only 5 of them were found in fish fillet and fish liver.…”

Bioaccumulation of Highly Hydrophobic Organohalogen Flame Retardants from Sediments: Application of Toxicokinetics and Passive Sampling Techniques

“…Recent advances in analytical techniques have facilitated the detection of trace levels of HHOFRs in biota, thus the bioavailability of these contaminants is now a potential issue 26,27 even though HHOFRs were once considered not to be bioavailabile. 7,28 While HHOFRs bioaccumulated in L. variegatus, their bioavailability was relatively low with BSAF values ranging from 0.021 ± 0.003 to 0.481 ± 0.082 g OC/g lipid ( Table 1).…”

Emerging and legacy flame retardants in UK human milk and food suggest slow response to restrictions on use of PBDEs and HBCDD

“…This apparent contradiction may be attributable to a gradual shift over time of PBDEs from the indoor to the outdoor environment of which one manifestation may be increasing concentrations of PBDEs in the human diet (Harrad and Diamond, 2006). Furthermore, as BDE 209 has been reported to debrominate to lower brominated PBDEs in both terrestrial and aquatic biota (Gandhi et al, 2011;La Guardia et al, 2007;Letcher et al, 2014;Stapleton et al, 2006;Tian et al, 2012;Van den Steen et al, 2007), it is plausible that ongoing transfer from the indoor environment to outdoors and subsequent debromination of BDE 209 in biota, could drive temporal increases in concentrations of lower congener PBDEs in food samples. This hypothesis is supported by the relatively high ratios of tri-hexa-BDEs/BDE 209 in foodstuffs in this study compared to those in two previous UK studies ( Figure S2) even though levels of BDE-209 were comparable (UK Food Standards Agency, 2006; UK Food and Environment Research Agency, 2009) ( Figure S3).…”