Tetrabromobisphenol-A and Hexabromocyclododecane in Birds from an E-Waste Region in South China: Influence of Diet on Diastereoisomer- and Enantiomer-Specific Distribution and Trophodynamics

Abstract

Tetrabromobisphenol-A (TBBPA) and three diastereomers of hexabromocyclododecane (HBCD) were examined in the muscles of six bird species and their diet collected from an e-waste recycling region (Qingyuan) in South China. Stable isotope ratios (delta15N and delta13C) were analyzed to measure the diet source and trophic levels (TLs) of the birds. The median TBBPA and HBCD concentrations in the birds ranged from 28 to 173 and not detectable to 1995 ng/g lipid weight, respectively. The diastereoisomeric pattern shows the predominance of alpha-HBCD in birds feeding in an aquatic environment and that of gamma-HBCD in birds feeding in a terrestrial environment, whereas no clear preference for alpha isomer or gamma isomer was found in birds that inhabited freshwater wetland. A significant positive correlation between delta13C and percentage of alpha-HBCD was observed, indicating the importance of diet exposure pathways in the determination of HBCD diastereoisomer pattern. The enantiomer fractions (EFs) for alpha-HBCD differed substantially between aquatic and terrestrial bird species with a significant enrichment of (+) alpha-HBCD enantiomer for aquatic birds and a preferential enrichment of (-) alpha-HBCD enantiomer for terrestrial birds. The similarity in diastereoisomer profiles of HBCD and the EFs of alpha-HBCD between prey (fish) and predator (Chinese pond heron) also suggested that dietary exposure is an important contributor for the observed diastereoisomer- and enantiomer-specific distribution of HBCD in birds. Trophic magnification was observed for alpha-HBCD and TBBPA as concentrations increased with the TLs of the birds defined by delta15N, but only alpha-HBCD showed a strong positive relationship (p=0.001). The biomagnification factors for alpha- and gamma-HBCD and TBBPA were calculated based on individual predator/prey feeding relationships for two species.

Alteration of Diastereoisomeric and Enantiomeric Profiles of Hexabromocyclododecanes (HBCDs) in Adult Chicken Tissues, Eggs, and Hatchling Chickens

“…19 The EFs of γ-HBCD were seldom reported in tissues of chickens or wild birds because of the low values of γ-HBCD. [17][18][19]32 In the study of He et al, 32 the EF values for γ-HBCD were available for 6 out of 40 wild bird muscle samples, ranging from 0.55 to 0.61, which were lower than our results (0.84 ± 0.05 in adult chicken muscle). In our recent in vitro study using chicken liver microsomes, 33 no diastereomeric or enantiomeric pattern changes of HBCDs were catalyzed by cytochrome P450 (CYP) enzymes.…”

Levels and distribution of hexabromocyclododecane (HBCD) in environmental samples near manufacturing facilities in Laizhou Bay area, East China

“…The levels in the aquatic species were slightly lower than those in the marine species near known point sources in the Netherlands (9-1110 ng g À1 lw) 30 and the freshwater species near the textile industry in Sweden (downstream industrial effluents 970-1800 ng g À1 dw). 18 However, they were at the same level as in other freshwater fish, e.g., in crucian carp in South China (21-378 ng g À1 lw) 29 and in fish from English lakes (14-290 ng g À1 lw). 23 P HBCD concentrations varied significantly in the different aquatic species and tissues.…”

Separation of polybrominated diphenyl ethers in fish for compound-specific stable carbon isotope analysis

“…Then, the extract was further cleaned up using SPE column chromatography, which has been proven to be an effective method for purifying PBDEs in small samples of biota (He et al, 2010;Yu et al, 2011). In consideration of the large sample volumes used in the present study, a separation step using a complex silica gel column was added between the GPC treatment and SPE column chromatography steps.…”