Bioaccumulation of Persistent Halogenated Organic Pollutants in Insects: Common Alterations to the Pollutant Pattern for Different Insects during Metamorphosis.

Few studies have examined the accumulation and fate of persistent halogenated organic pollutants (HOPs) in insects. We measured HOPs, including dichlorodiphenyltrichloroethanes (DDTs), polychlorinated biphenyls, and halogenated flame retardants, in insects from four taxonomic groups collected from an e-waste site. Dragonfly larvae collected from a pond contained the highest concentrations of all chemicals except DDTs, while the litchi stinkbugs contained the lowest. Different insect taxa exhibited different contaminant patterns which could be attributed to their habitats and feeding strategies. Bioaccumulation factors for dragonfly larvae and biomagnification factors for moth and grasshopper larvae were significantly positively correlated with the octanol-water partition coefficient of the chemicals (log KOW < 8). Common nonlinear correlations between the ratio of larval to adult concentrations and log KOW were observed for all taxa studied. The ratio of concentrations decreased with increasing values of log KOW (log KOW < 6-6.5), then increased (6 < log KOW < 8) and decreased again (log KOW > 8). This result implies that the mechanism that regulates organic pollutants in insects during metamorphosis is common to all the taxa studied.

Polychlorinated Biphenyls (PCBs) in Human Hair and Serum from E-Waste Recycling Workers in Southern China: Concentrations, Chiral Signatures, Correlations, and Source Identification.

Hair is increasingly used as a biomarker for human exposure to persistent organic pollutants (POPs). However, the internal and external sources of hair POPs remain a controversial issue. This study analyzed polychlorinated biphenyls (PCBs) in human hair and serum from electronic waste recycling workers. The median concentrations were 894 ng/g and 2868 ng/g lipid in hair and serum, respectively. The PCB concentrations in male and female serum were similar, while concentrations in male hair were significantly lower than in female hair. Significant correlations between the hair and serum PCB levels and congener profiles suggest that air is the predominant PCB source in hair and that hair and blood PCB levels are largely dependent on recent accumulation. The PCB95, 132, and 183 chiral signatures in serum were significantly nonracemic, with mean enantiomer fractions (EFs) of 0.440-0.693. Nevertheless, the hair EFs were essentially racemic (mean EFs = 0.495-0.503). Source apportionment using the Chemical Mass Balance model also indicated primary external PCB sources in human hair from the study area. Air, blood, and indoor dust are responsible for, on average, 64.2%, 27.2%, and 8.79% of the hair PCBs, respectively. This study evidenced that hair is a reliable matrix for monitoring human POP exposure.

Organohalogen contamination in passerine birds from three metropolises in China: geographical variation and its implication for anthropogenic effects on urban environments.

Contamination of organohalogen pollutants (OHPs), including dichlorodiphenyl trichloroethane and its metabolites (DDTs), polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs), decabromodiphenylethane (DBDPE), hexabromocyclododecanes (HBCDs), and dechlorane plus (DP) in three metropolises of China, Beijing, Wuhan, and Guangzhou, and a reference rural site were determined using terrestrial residential passerine species as bioindicator. DDTs dominated in Wuhan whereas flame retardants dominated in Guangzhou and Beijing. No geographical variation was found for PCB levels but it exhibited different homologue profiles among different sites which could be attributed to different dietary sources of birds. Industry characteristics of the sampling location contributed to the geographical differences in the occurrence and contamination profile of OHPs. The transformation of traditional agriculture characterized contamination profiles to industry characterized profiles in Beijing and Guangzhou implicates significantly environmental concern on the flame retardants contamination in non-hot-spot regions of China.

Diasteroisomer and enantiomer-specific profiles of hexabromocyclododecane and tetrabromobisphenol A in an aquatic environment in a highly industrialized area, South China: vertical profile, phase partition, and bioaccumulation.

Tetrabromobisphenol A (TBBPA) and hexabromocyclododecanes (HBCDs) were determined in water, sediments, sediment cores, and three fish species from a river running through a highly industrialized area in South China. TBBPA concentrations exceeded those of HBCDs in the sediment and the dissolved phase of water and its levels in fish were at the high end of worldwide figures. 26% of HBCDs and 99% of TBBPA were found in dissolved phase of water. Plecostomus occupying high trophic level exhibited higher HBCD levels and higher abundance of α-HBCD than mud carp and nile tilapia which occupy low trophic level. An enrichment of (+)-α-HBCD in three fish species but (-)-α-HBCD in sediment was observed. As for γ-HBCD, most of sediment exhibited racemic while a species-dependence in fish sample was found. No clear trend was found for vertical distribution of enantiomeric profile for γ-HBCD, suggesting that the enantioselectivity of degradation of γ-HBCD is limited.

Using compound-specific stable carbon isotope analysis to trace metabolism and trophic transfer of PCBs and PBDEs in fish from an e-waste site, South China.

Two fish species (mud carp and northern snakehead) forming a predator/prey relationship and sediment samples were collected from a pond contaminated by e-waste. The concentrations and stable carbon isotope ratios (δ(13)C) of individual polychlorinated biphenyl (PCB) and polybrominated diphenyl ether (PBDE) congeners were measured to determine if compound-specific carbon isotope analysis (CSIA) could be used to provide insight into the metabolism and trophic dynamics of PCBs and PBDEs. Significant correlations were found in the isotopic data of PCB congeners between the sediment and the fish species and between the two fish indicating identical origin of PCBs in sediment and fish. Most PCB congeners in the fish species were enriched in (13)C compared with the PCB congeners in the sediments as a result of isotopic fractionation during the metabolism of PCBs in fish. The isotopic data of several PCB congeners showing isotopic agreement or isotopic depletion could be used for source apportionment or to trace the reductive dechlorination process of PCBs in the environment. The PCB isotopic data covaried more in the northern snakehead than in the mud carp when compared to the sediment, implying that a similar isotopic fractionation occurs from the prey to the predator fish for a PCB congener possibly due to similar metabolic pathways. The PBDE congener patterns differed in the three sample types with a high abundance of BDE209, 183, 99, and 47 in the sediment, BDE47, 153, and 49 in the mud carp and BDE47, 100, and 154 in the northern snakehead. The isotopic change of BDE congeners, such as BDE47 and BDE49, in two fish species, provides evidence for biotransformation of PBDEs in biota. The results of this study suggest that CSIA is a promising tool for deciphering the fate of PCBs and PBDEs in the environment.

Tissue accumulation and species-specific metabolism of technical pentabrominated diphenyl ether (DE-71) in two predator fish.

The tissue-specific accumulation and species-specific metabolism of polybrominated diphenyl ethers (PBDEs) in two predator fish species (redtail catfish and oscar fish) feeding on the same prey (tiger barb) that was exposed to technical pentabrominated diphenyl ether (DE-71) in the laboratory were investigated. The trends in the wet-weight tissue concentration of PBDEs in two predatory fish species suggested that the tissue distribution of PBDEs occurs through a series of events involving passive diffusion to the lipid compartment. A comparison of the fugacities of PBDEs in various tissues and in the serum revealed that the liver, gill, and perivisceral adipose tissue readily achieved equilibrium with the serum, but the muscle, kidney, and intestine exhibited the potential to accumulate PBDEs. The lower fugacities of PBDEs in the intestine may have significance in the transportation of PBDEs from prey to predatory fish. No tissue-specific differences in PBDE congener profiles were found, while interspecies differences in PBDE profiles were evident. The difference in profiles between two species could be attributed to species-specific debromination of PBDE. No metabolic debromination of PBDE was observed in redtail catfish, but extensive debromination of PBDEs occurred in oscar fish. Several hydroxylated PBDEs (OH-PBDEs) were detected in serum samples from the two fish species, but no methoxylated PBDEs were found. The similarities in the OH-PBDE congener profile and the ratio of OH-PBDEs to total PBDEs between the two fish species indicated that the hydroxylation of PBDEs might not be species-specific.

Dechlorane Plus in serum from e-waste recycling workers: influence of gender and potential isomer-specific metabolism.

Dechlorane Plus (DP) and its dechlorinated product, anti-Cl11-DP, were measured in serum of 70 occupationally exposed workers in an e-waste recycling region and 13 residents of an urban area in South China. The DP levels were significantly higher in the workers (22-2200 ng/g with median of 150 ng/g lipid) than in the urban residents (2.7-91 ng/g with median of 4.6 ng/g lipid). The DP concentrations in females were found to be associated with their age but such relation was not found for males. Significant differences in DP levels and DP isomer composition were found between genders. The females had remarkably higher DP levels and f(anti) values (fraction of anti-DP to total DPs) in serum than the males. Anti-Cl11-DP was significantly correlated with anti-DP for both genders but with different slope of regression line. The ratios of anti-Cl11-DP to anti-DP (mean of 0.017) in males were significantly higher than those (mean of 0.010) in females. Combining with the lower f(anti) values in males, it is likely that males have higher metabolic potential for DPs than females which resulted in the lower DP loading in serum. However, the different patterns of selective uptake and/or excretion of different compounds between genders cannot be eliminated as a possible reason for the observed gender differences. This study is the first to report on the gender difference in DP accumulation in human, and its mechanism is worth further investigation.

[Horizontal and vertical distribution of polybrominated diphenyl ethers (PBDEs) in river sediment from a typical electrical equipment industrial area].

Polybrominated diphenyl ethers (PBDEs) were determined in sediment collected from a river in a typical electrical equipment industrial area, Ronggui, Foshan. Eight samples were collected from river sediment. The results indicated that PBDEs were presented in all samples. Spatial trends showed that the concentrations of PBDEs in all sediment samples were ranged from 62 ng x g(-1) to 349 ng x g(-1), with an average of 178 ng x g(-1). The predominant congener was BDE-209 (90% - 99%), which ranged from 56-337 ng x g(-1), with an average of 171 ng x g(-1). Some of congeners such as BDE-196, 197 and 203 may be were the degradation product of BDE-209. Vertically, the concentrations of PBDEs were increased with the depth, whereas the concentrations were 147 ng x g(-1) in layer 0-10 cm and 260 ng x g(-1) in layer 30-40 cm, respectively. Distribution profile of PBDEs in vertical direction was similar in different depths. The commercial deca-BDE (94%), which contained BDE-209, 208, 207 and 206, was the dominate pollutant with minor contributions from penta-and octa-BDEs. The results suggested that this area was polluted by PBDEs and BDE-209 was the most dominate congener, which is related with the manufacturing activities for electrical equipment.

Gastrointestinal absorption, metabolic debromination, and hydroxylation of three commercial polybrominated diphenyl ether mixtures by common carp.

The gastrointestinal absorption, metabolic debromination, and hydroxylation of three commercial brominated diphenyl ether (BDE) mixtures were separately studied in juvenile common carp. The absorption rate of penta-BDE was higher than that of octa- and deca-BDE, likely because of the lower molecular volumes of its major congeners. However, no significantly positive relationships were found between the number of bromine atoms and the absorption rate, especially for congeners with a bromine atom number larger than six. The major congeners in fish carcass were, respectively, BDE-47 and BDE-100 in the penta-BDE exposure; BDE-154, -155, -149, and BDE-153 in the octa-BDE exposure; and BDE-154, -155, -149, -188, -179, and BDE-202 in the deca-BDE exposure. Congeners with at least one meta- or para- doubly flanked bromine atom easily undergo metabolic debromination in fish. None of the targeted MeO-polybrominated diphenyl ether (PBDE) congeners were detected in serum samples, implying that the methylation of OH-PBDE is not likely occurring in fish. Eleven OH-PBDEs and several unidentified OH-PBDE congeners were found in penta-BDE-exposed fish. The similar level among three mono-OH-BDE47 congeners suggested that the position of OH in the phenyl ring is not selective. The hydroxylation is not a significant metabolic pathway compared with debromination. No OH-PBDE congeners were found in the serum samples from deca-BDE-exposed fish, which may attributable to the low level of PBDE precursors in fish.

Biomagnification of higher brominated PBDE congeners in an urban terrestrial food web in north China based on field observation of prey deliveries.

As an important group of brominated flame retardants, polybrominated diphenyl ethers (PBDEs) persist in the wildlife food webs. However, the biomagnification of PBDEs has not been adequately studied in the terrestrial food webs. In this study, a terrestrial food web composed of common kestrels, sparrows, rats, grasshoppers, and dragonflies in the urban environment from northern China was obtained. A field prey delivery study, reinforced by δ¹³C and δ¹5N analyses, indicates that sparrows are the primary prey items of common kestrels. Concentrations of PBDEs were in the following order: common kestrel > sparrow > rat > grasshopper and dragonfly with BDE-209 as the dominant congener. Biomagnification factors (BMFs) were calculated as the ratio between the lipid normalized concentrations in the predator and prey. The highest BMF (6.9) was determined for BDE-153 in sparrow/common kestrel food chain. Other higher brominated congeners, such as BDE-202, -203, -154, -183, -197, and -209, were also biomagnified in this terrestrial food chain with BMF of 1.3-4.7. BDE-47, -99, and -100 were found to be biodiluted from sparrow to common kestrel (BMFs < 1). Measured BMF values for BDE-153, -47, -99, and -100 were consistent with predicted values from a nonsteady-state model in American kestrels from another study. Retention factors and metabolism of BDE congeners may be confounding factors influencing the measured BMFs in this current study.

Bioaccumulation of several brominated flame retardants and dechlorane plus in waterbirds from an e-waste recycling region in South China: associated with trophic level and diet sources.

The present study is primarily designed to examine the role played by dietary sources on polybrominated diphenyl ethers (PBDE) congener profiles in waterbirds collected in an e-waste recycling region in South China. Some emerging halogenated flame retardants (HFRs), such as dechlorane plus (DP), 2,3,4,5,6-pentabromoethyl benzene (PBEB), pentabromotoluene (PBT), and 1,2-bis(2,4,6-tribromophenoxy)ethane (BTBPE), were also quantified. Stable isotopes (δ(15)N and δ(13)C) were analyzed to assess the trophic levels and dietary sources of the birds. PBDEs were found to be the predominant HFRs, followed by DP, PBT, PBEB, and BTBPE. The birds in which BDE209 was predominant have differential δ(13)C and δ(15)N signatures compared with other birds, suggesting that dietary source is one of the important factors in determining the PBDE congener profile in birds. The levels of ΣPBDEs, PBEB, and PBT were significantly correlated with the trophic level (δ(15)N) for avian species which are located in a food chain, indicating the biomagnification potential of these compounds. No correlation was found between DP concentrations and trophic level of the birds. There is a significantly negative correlation between the fraction of anti-DP and δ(15)N, suggesting that the metabolic capability of DP in birds increases with the trophic level of the birds.

[Concentration and emission fluxes of halogenated flame retardants in sewage from sewage outlet in Dongjiang River].

Fourteen sewage samples from sewage outlets in Dongjiang River were collected. Halogented flame retardants were extracted and purified using dichloromethane and alumina/silica-gel column, respectively. The concentrations of halogenated flame retardants were measured utilizing GC/MS, and the emission fluxes were estimated. Decabromodiphenyl ethane (DBDPE) was the predominant halogenated pollutant (accounting for 64%) in sewage with the concentration ranging from 9.1 ng/L to 990 ng/L. The concentrations of polybrominated biphenyl ether (PBDEs), dominated by BDE209, in the sewage ranged from 6.9 ng/L to 470 ng/L, accounting for 30% of total halogenated flame retardants. The concentrations of other flame retardants, such as dechlorane plus (DP), 1, 2-bis(2, 4, 6-tribromophenoxy) ethane (BTBPE), hexabromobenzene (HBB), and pentabromotoluene (PBT), were ranged within 0.17-23.6, nd-26.3, nd-1.45 and nd-0.45 ng/L, respectively. The concentrations of PBDEs in sewage of Dongjiang River were comparable to those in influent wastewater of sewage treatment plants of Guangzhou, suggesting that the wastewater was discharged directly into Dongjiang River without any treatment. The emission flux of halogenated flame retardants from sewage was 191 kg. Emission from industrial wastewater, contributed to 48%-91% of total emission, was the main source of halogenated flame retardants.

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.

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.

Polybrominated diphenyl ethers (PBDEs), polychlorinated biphenyles (PCBs), hydroxylated and methoxylated-PBDEs, and methylsulfonyl-PCBs in bird serum from South China.

Polybrominated diphenyl ethers (PBDEs), polychlorinated biphenyls (PCBs), and their derivatives, hydroxylated (OH) and methoxylated (MeO) PBDEs and methylsulfonylated (MeSO(2)) PCBs, were measured in sera of eight bird species collected from an e-waste recycling region in South China. Concentrations of summation operatorPCBs, ranging from 38 to 1700 ng/g lipid weight (lw), were one to two orders of magnitude higher than concentrations of summation operatorPBDEs (0.64-580 ng/g lw). The significantly positive relationship between PCB and PBDE concentrations suggested a similar pathway of exposure to these compounds. Compared with muscle in birds, serum might prefer to accumulate and/or retain less brominated/chlorinated congeners. 3-OH-BDE47 and 2'-OH-BDE68 were detected in more than 80% of the collected bird serum samples (range: not detectable (nd) to 13 and nd to 7.8 ng/g lw, respectively). The other three OH-PBDE congeners (4'-OH-BDE-17, 6-OH-BDE47, and 4'-OH-BDE-49) and two MeO-PBDE congeners (3-MeO-BDE47 and 6-MeO-BDE47) were occasionally detected in bird sera at concentrations ranging from nd to 2.5 ng/g lw. Both natural sources and metabolic transformation of PBDEs could contribute to the presence of these PBDE derivatives in the birds. The two MeSO(2)-PCB congeners (4-MeSO(2)-CB49 and 4-MeSO(2)-CB101) under investigation were detected at respective concentration ranges of nd to 12 and nd to 0.68 ng/g lw. 4-MeSO(2)-CB101 exhibited the highest concentration among the nine PCB and PBDE derivatives studied, indicating that biotransformation via the mercapturic acid pathway of PCBs might have occurred in the studied bird species.