The concentrations and enantiomer fractions (EFs) of α-, β-, and γ-hexabromocyclododecanes (HBCDs) were measured in chicken diet sources (soil and chicken feed), home-raised adult chicken (Gallus domesticus) tissues, eggs during incubation, and hatchling chicken tissues. HBCD concentrations were not detected–0.69 ng/g dry weight (dw) and 25.6–48.4 ng/g dw in chicken feed and soil, respectively. HBCDs were detected in all adult chicken tissues, except the brain, at median levels of 13.1–44.0 ng/g lipid weight (lw). The proportions of α-HBCD in total HBCDs increased from 51% in soil to more than 87% in adult chicken tissues. The accumulation ratios (ARs) of α-HBCD from diet to adult chicken tissues were 4.27 for liver, 11.2 for fat, and 7.64–12.9 for other tissues, respectively. The AR and carry-over rate (COR) of α-HBCD from diet to eggs were 22.4 and 0.226, respectively. The concentrations of α-HBCD in hatchling chicken liver (median: 35.4 ng/g lw) were significantly lower than those in hatchling chicken pectoral muscle (median: 130 ng/g lw). The EFs of α-HBCD decreased from soil to adult chicken tissues and from eggs to hatchling chicken liver. Meanwhile, the EFs of γ-HBCD increased from soil to adult chicken tissues. These results indicate the preferential enrichment of (−)-α-HBCD and (+)-γ-HBCD in chickens. The alteration of diastereoisomeric and enantiomeric patterns of HBCDs might be influenced by the different absorption and elimination rates of the six HBCD enantiomers as well as variations in HBCD metabolism in chickens.

Compound-specific and enantiomer-specific carbon isotope composition was investigated in terms of biotransformation of polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers (PBDEs) as well as atropisomers of chiral PCB congeners in fish by exposing common carp (Cyprinus carpio) to certain PCB and PBDE congeners. The calculated carbon isotope enrichment factors (εC) for PCB 8, 18, and 45 were −1.99, −1.84, and −1.70‰, respectively, providing evidence of the metabolism of these congeners in fish. The stable carbon isotopic compositions of PBDE congeners clearly reflect the debromination of PBDEs in carp. Significant isotopic fractionation was also observed during the debromination process of BDE 153 (εC = −0.86‰). Stereoselective elimination of chiral PCB congeners 45, 91, and 95 was observed, indicating a stereoselective biotransformation process. The similar εC values for E1-PCB 45 (−1.63‰) and E2-PCB 45 (−1.74‰) indicated that both atropisomers were metabolized by the same reaction mechanisms and stereoselection did not occur at carbon bond cleavage. However, the εC values of (+)-PCB 91 (−1.5‰) and (−)-PCB 95 (−0.77‰) were significantly different from those of (−)-PCB 91 and (+)-PCB 95, respectively. In the latter, no significant isotopic fractionations were observed, indicating that the stereoselective elimination of PCB 91 and 95 could be caused by a different reaction mechanism in the two atropisomers.

Polychlorinated biphenyls (PCBs) and enantiomer fractions (EFs) of PCB enantiomers (PCBs 95, 132, 135, and 149) were investigated in soil and chicken feed, chicken (Gallus domesticus) tissues, eggs on 0, 7, and 14 days after the onset of incubation, and newborn chick tissues. The EF values of PCBs 95, 132, and 149 changed significantly from soil to chicken tissues, and the values in the liver exhibited the highest deviation from the racemic ratio, indicating enantiomer-selective metabolism in hens. Congeners, which are highly resistant to degradation, such as PCBs 138, 153, and 180, exhibited the highest maternal transfer potentials when muscle and liver were used to assess the maternal transfer. However, uniform transfer ratios were observed for most of the PCB congeners when visceral fat was used. The EFs of chiral PCBs in eggs either did not match with muscle or with liver or were similar to those in visceral fat. These results indicate that hens mainly mobilized visceral fat for egg formation and PCBs were deposited in eggs by associating with these lipid materials. Further enantiomeric enrichment of PCBs 95, 132, and 149 occurred in the newborn chick tissues. However, an opposite enantioselectivity for PCB 135 in newborn chicks was observed. These results indicate that the potential toxicity of PCB enantiomers to newborn chicks may be different from that of adults.

Tetrabromobisphenol A (TBBPA) and hexabromocyclododecanes (HBCDs) were analyzed in 12 tissues of prey (mud carp) and predator (northern snakehead) fish from an e-waste area, South China. The TBBPA concentrations in different tissues ranged from 0.03 to 2.85 ng/g wet weight (ww) in mud carp and 0.04 to 1.30 ng/g ww in northern snakehead. The concentrations of HBCDs ranged from 0.07 to 96.9 ng/g ww in mud carp and 0.18 to 240 ng/g ww in northern snakehead. HBCD levels in tissues were correlated with lipid content for both fish species, while this correlation was only found in mud carp for TBBPA. Meanwhile, northern snakehead exhibited higher HBCD levels but lower TBBPA levels than mud carps. These observations are attributed to the more polar and reactive properties of TBBPA than HBCDs. α-HBCD was the predominant diastereoisomer of HBCDs in all tissues of mud carp and northern snakehead, except for chyme of mud carp. All the analyzed tissues in mud carp showed an enrichment of (+)-α-HBCD enantiomer with EF (enantiomeric fraction) values of 0.53–0.62, but that in northern snakehead showed an enrichment of (−)-α-HBCD enantiomer with EF values of 0.35–0.5. Considering the fact that the mud carp is one of the diet items of northern snakehead, the different enantiomer accumulation characteristics of α-HBCD between the two fish species in the present study indicated that prey and predator fish could prefer to biotransform different enantiomers of α-HBCD.

Halogenated organic pollutants (HOPs)—including organochlorine pesticides (OCPs), polychlorinated biphenyls (PCBs), polybrominated diphenylethers (PBDEs), polybromobiphenyls (PBBs), dechlorane plus (DP), tetrabromobisphenol A (TBBPA), and hexabromocyclododecanes (HBCDs) as well as PCB metabolites (methylsulfone [MeSO2-]) and hydroxylated (OH-) PCBs and OH-PBDEs—were determined in the serum of mud carp and northern snakehead from an electronic-waste (e-waste) site in South China. The average concentrations (mean ± SD) of ΣPCBs, ΣPBDEs, ΣOCPs, ΣPBBs, ΣTBBPA, ΣHBCDs, and ΣDP were 1410 ± 324, 70 ± 20, 3.0 ± 0.4, 2.8 ± 0.8, 1.6 ± 0.4, 1.0 ± 0.2, and 0.3 ± 0.03 ng/g wet weight (ww) in mud carp and 6430 ± 781, 468 ± 49, 22.4 ± 1.1, 7.0 ± 0.6, 2.9 ± 2.3, 5.5 ± 1.1, and 4.6 ± 0.6 ng/g ww in northern snakehead, respectively. MeSO2-PCBs, OH-PCBs, and OH-PBDEs were detected at a total concentration of 0.44 ± 0.03 and 9.7 ± 0.3 ng/g ww in mud carp and northern snakehead, respectively. The congener profiles of PCBs, PBDEs, OH/MeSO2-PCBs, and OH-PBDEs were found to be significantly different between the two fish species, possibly as a result of species-specific bioaccumulation and/or metabolism of the HOPs. Chirality of ten PCB congeners and α-HBCD, as well as the fanti values of DP in the serum samples, supported the species-specific biotransformation of HOPs. Furthermore, the presence of covaried and counter-varied enantiomeric fractions of PCBs between the two fish species indicated species- and congener-specific enantiomer enrichment of PCBs.

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 (δ13C) 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 13C 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.

A purification method for lower polybrominated diphenyl ethers (PBDEs, from tri- to hexa-BDE) in sediment for compound-specific isotope analysis (CSIA) was developed in this study. The compounds were extracted using a Soxhlet apparatus with addition of activated alumina and Florisil in the paper tube during the Soxhlet extraction provided for less complex extracts. Then, the extract was isolated from polar compounds using a multi-layer silica gel column, separated into different fractions using alumina/silica (Al/Si) gel columns and finally purified using a Florisil column. The mean recoveries of the major PBDE congeners in the spiked samples ranged from 76.2% to 82.4%. The purity of the samples was verified by GC–MS in full scan mode. The stable isotopic integrity of the spiked samples after the purification was tested by comparing the stable carbon isotope ratios (δ13C) of the processed and the unprocessed standard materials. The differences in the δ13C values for each compound between the processed and unprocessed standards were less than 0.5‰, with the exception of BDE100 (0.54‰). Finally, the purification and isotope analysis method was successfully applied to measure the δ13C of PBDEs in sediments. This application of the method indicated that CSIA seems to be a promising method for providing intrinsic characteristics for further environmental fate studies of PBDEs.Highlights► A purification method was developed for PBDEs in sediment for CSIA. ► The method allows the CSIA of PBDEs in sediment without isotopic fractionation. ► The δ13C values of PBDEs in real sediment samples were determined by this method. ► Future application of CSIA for PBDE in the environment is feasible.

Short-chain and medium-chain chlorinated paraffins (SCCPs and MCCPs) were measured in sediments from ponds, rivers and tributaries, and an estuary, as well as a sediment core in the Pearl River Delta (PRD), South China, to comprehensively investigate the spatial and temporal distributions of CPs. The concentrations of SCCPs and MCCPs in sediment were varied from 320 to 6600 ng/g and from 880 to 38 000 ng/g, respectively. Elevated CP concentrations were found in pond sediments (means of 2800 and 21 000 ng/g for SCCPs and MCCPs) in the e-waste recycling area and in river sediments (means of 1200 and 3900 ng/g for SCCPs and MCCPs) in the highly industrialized areas. The significant positive correlations between SCCP concentration and MCCPs/SCCPs in the highly industrialized areas reflected the emission of local industry activities, while the significant negative correlations in the low industrial activity areas could be linked to long-range transportation of CPs. An increased abundance of short chain and low chlorinated congeners was observed in the low industrial activity areas compared to the industrialized areas. The preferred transportation of short chain and low chlorinated congener CPs and the dechlorination of higher chlorinated congeners CPs were the most likely reasons. The vertical profile of CPs in the sediment core indicated a rapid increase in the usage of CPs and a shift to more MCCPs in recent years. The decreased chlorine content of CPs with increasing sediment depth indicated the possibility of dechlorination of higher chlorinated congeners (Cl9 and Cl10) after deposition in sediments with greater dechlorination potential for short chain CPs than long chain CPs.

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.

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 (δ15N and δ13C) 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 δ13C and δ15N 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 (δ15N) 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 δ15N, suggesting that the metabolic capability of DP in birds increases with the trophic level of the birds.

Heavy metals were measured in hair from occupationally and nonoccupationally exposed populations in an e-waste recycling area and from residents from a control rural town. The levels of five heavy metals were in the following order of Zn > Pb, Cu > Cd > Ni, with the highest levels found in the occupationally exposed workers. The levels of Cd, Pb, and Cu were significantly higher in residents from the e-waste recycling area than in the control area. Elevated Cd, Pb, and Cu contents along with significant positive correlations between them in hair from the e-waste recycling area indicated that these metals were likely to have originated from the e-waste recycling activities. The similarity in heavy metal pattern between children and occupationally exposed workers indicated that children are particularly vulnerable to heavy metal pollution caused by e-waste recycling activities. The increased Cu exposure might be a benefit for the insufficient intake of Cu in the studied area. However, the elevated hair Cd and Pb levels implied that the residents in the e-waste area might be at high risk of toxic metal, especially for children and occupationally exposed workers.

Birds have been used successfully for biomonitoring of the levels and effects of persistent organic pollutants (POPs) in the environments; however, there is exceedingly little data on organochlorinated pesticide (OCPs) and polychlorinated biphenyls (PCBs) residues in bird inhabiting in China. In the present study, we detected the concentrations of PCBs, dichlorodiphenyltrichloroethane and its metabolites (DDTs) and hexachlorocyclohexanes (HCHs) in muscle, liver and kidney of birds that inhabit in an e-waste recycling site. Associated with the stable isotope ratio (δ15N), we investigated the effect of trophic level on the body burdens of persistent contaminants in birds. The tissue distributions of contaminants in these birds were examined, and a preliminary risk assessment was also conducted.Specimens from eight bird species were collected from Qingyuan County, Guangdong Province, South China. Pectoral muscle, liver and kidney tissues were Soxhlet-extracted and finally dissolved in isooctane. Both PCBs and OCPs were analyzed by gas chromatography-mass spectrometry. The subsamples for nitrogen stable isotope analysis were lyophilized, ground and analyzed by a flash EA 112 series elemental analyzer interfaced with an isotope ration mass spectrometer.PCBs exhibited the highest concentrations among all target compounds, and a preliminary risk assessment suggested that adverse effects might occur in some birds for its high level. Generally, the concentrations of pollutants in liver and kidney were higher than those in muscle, which was mainly driven by passive diffusion to the ‘lipid-compartment’. Significant differences in level of contaminants were obtained among species due to the varieties in dietary composition and habitat. An increasing trend was obtained between concentrations of PCBs and DDTs with trophic levels; however, HCHs exhibited the same level among species.Because of the e-waste recycling activities, the study area has been heavily polluted by PCBs. Studies on the species-specific hazard assessment associated with exposure to PCBs are urgently needed in the study of birds in the area.

Several currently used non-polybrominated diphenyl ether (PBDE) brominated flame retardants (BFRs), including hexabromocyclododecanes (HBCDs), 1,2-bis(2,4,6-tribromophenoxy)ethane (BTBPE), decabromodiphenyl ethane (DBDPE), hexabromobenzene (HBB), pentabromoethylbenzene (PBEB), and pentabromotoluene (PBT), are examined in the components of a freshwater food web from an electronic waste recycling site, South China. All these BFRs are detectable in the food web, with average concentrations of 13.9−868, 1.71−518, < 3.8−338, 197−3099, 3.98−25.6, and 1.20−3.60 ng/g lipid wt for HBCDs, BTBPE, DBDPE, HBB, PBEB, and PBT, respectively. Food web magnification is observed for (+)-α-, (−)-α-, (±)-α-, and total HBCDs, and HBB, with trophic magnification factors (TMFs) of 2.22, 2.18, 2.19, 1.82, and 1.46, respectively; whereas there is trophic dilution of BTBPE and PBT through the food web. The TMFs for (+)-α-, (−)-α-, and (±)-α-HBCDs are comparable to those of PBDEs detected previously in the same food web. Biota samples show a shift from γ- toward α-HBCD compared with the suspended particles, sediment, and HBCD technical mixtures, with a significant increase of α-HBCD on ascending trophic levels. Except for α-HBCD in suspended particles and sediment, all the HBCD enantiomers detected are nonracemic in the environmental matrix. In biota, nonracemic residues of α-HBCD were observed in mud carp and crucian carp; β-HBCD in prawn, mud carp, and crucian carp; and γ-HBCD in water snake, with preferences for (+)-α-, (−)-β-, and (+)-γ-HBCDs.

Dechlorane Plus (DP), a highly chlorinated flame retardant, has been detected in water, sediment, and aquatic organisms in a reservoir in the vicinity of electronic waste recycling workshops in South China. The biomagnification potential of DP in the food web was assessed and compared with that of polybrominated diphenyl ethers (PBDEs) and polychlorinated biphenyls (PCBs). DP was detected in all of the aquatic species, with concentrations of 19.1−9630 ng/g lipid wt. A depletion of anti-DP was observed in organisms compared with abiotic samples and the fraction of anti-DP was found to be further decreased upon moving up the trophic levels. This result suggested a stereospecific metabolism of anti-DP and/or isomer-selective uptake of syn-DP was occurring in organisms. Both syn- and anti-DP were significantly biomagnified in the present food web, with trophic magnification factors (TMFs) of 11.3 and 6.6, respectively. The trophic magnification potentials of the DP isomers were generally comparable to or lower than those of the highly recalcitrant PCB congeners in the same food web, but were 2−3 times greater than those of PBDE congeners.

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 (δ15N and δ13C) 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 α-HBCD in birds feeding in an aquatic environment and that of γ-HBCD in birds feeding in a terrestrial environment, whereas no clear preference for α isomer or γ isomer was found in birds that inhabited freshwater wetland. A significant positive correlation between δ13C and percentage of α-HBCD was observed, indicating the importance of diet exposure pathways in the determination of HBCD diastereoisomer pattern. The enantiomer fractions (EFs) for α-HBCD differed substantially between aquatic and terrestrial bird species with a significant enrichment of (+) α-HBCD enantiomer for aquatic birds and a preferential enrichment of (−) α-HBCD enantiomer for terrestrial birds. The similarity in diastereoisomer profiles of HBCD and the EFs of α-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 α-HBCD and TBBPA as concentrations increased with the TLs of the birds defined by δ15N, but only α-HBCD showed a strong positive relationship (p = 0.001). The biomagnification factors for α- and γ-HBCD and TBBPA were calculated based on individual predator/prey feeding relationships for two species.

Dechlorane Plus (DP) and a dechlorination product, 1,6,7,8,9,14,15,16,17,17,18-octadeca-7,15-diene (anti-Cl11-DP), were measured in human hair and indoor dust collected from an e-waste recycling area and two control areas (rural and urban) in South China. DP was detected in hair and dust samples at concentrations ranging from 0.02−58.32 ng/g and 2.78−4197 ng/g, respectively. anti-Cl11-DP, mainly detected in human hair and dust samples from the e-waste recycling area, ranged from nd (nondetected) to 0.23 ng/g in hair and from nd to 20.22 ng/g in dust. Average values of anti-DP fractional abundance (fanti ratio) in hair of e-waste dismantling workers (0.55 ± 0.11) and dust from e-waste recycling workshops (0.54 ± 0.15) were significantly lower than those in other groups (0.62−0.76 means for hair and 0.66−0.76 means for dust). Significantly positive correlation between DP concentrations in dust and hair and similarity in fanti ratios between hair and dust suggest that ingestion of dust comprise one of the major routes for DP exposure. Significantly positive relationships were also observed between anti-Cl11-DP and anti-DP for both hair and dust samples with similar regression line slopes. The ratios of anti-Cl11-DP to anti-DP between hair and dust show no significant difference. These results suggest that anti-Cl11-DP in the human body is likely accumulated from the environmental matrix and not formed from biotransformation of the parent DP.

Polybrominated diphenyl ethers (PBDEs), polychlorinated biphenyls (PCBs), and their derivatives, hydroxylated (OH) and methoxylated (MeO) PBDEs and methylsulfonylated (MeSO2) PCBs, were measured in sera of eight bird species collected from an e-waste recycling region in South China. Concentrations of ∑PCBs, ranging from 38 to 1700 ng/g lipid weight (lw), were one to two orders of magnitude higher than concentrations of ∑PBDEs (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 MeSO2-PCB congeners (4-MeSO2-CB49 and 4-MeSO2-CB101) under investigation were detected at respective concentration ranges of nd to 12 and nd to 0.68 ng/g lw. 4-MeSO2-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.

An analysis method was developed for determining free and bound fractions of polybrominated ethers (PBDEs) and tetrabromobisphenol A (TBBPA) in sediments. The free PBDE and TBBPA were extracted with acetone/hexane (1:1, V/V) mixed solvent, and the bound fraction was released from the sediment by saponification at 80 °C. The PBDEs and TBBPA were separated by adjusting pH; PBDEs were determined by GC-NCI-MS after being cleaned up by multilayer silica gel column, and TBBPA was derived before preseparated by acid silica gel column and finally determined by GC-EI-MS. All the target compounds were quantitative by internal standard method. The limits of detection of eight lower brominated congeners (BDE 28, 47, 66, 100, 99, 154, 153, 183), deca-BDE (BDE 209), and TBBPA were 0.6–12.5 pg g−1, 172 and 4.2 pg g−1, respectively. This method is stable and reliable. The recoveries of all compounds were ranged from 74% to 106%, and the relative standard deviations were below 10%. This method appeared to be suitable for the measurement of different forms of PBDEs and TBBPA in sediment under reliable quality assurance and quality control.

•PBDEs, NBFRs, DPs, PFRs, and PCBs were studied in indoor dust from e-waste sites.•BDE 209, DBDPE, and TCIPP were the major contributors of PBDEs, NBFRs, and PFRs.•These contaminants have different sources in various e-waste sites.•Human exposure to contaminants was at the high-end of previous reports.•PFR occurrence and human exposure were studied for the first time in e-waste sites.Several classes of flame retardants, such as polybrominated diphenyl ethers (PBDEs), novel brominated flame retardants (NBFRs), dechlorane plus (DPs), and organophosphate flame retardants (PFRs), together with polychlorinated biphenyls (PCBs) were measured in indoor dust from five villages located in three e-waste recycling regions in Guangdong Province, South China. The medians of PBDEs, NBFRs, and PFRs in dust in five sites ranged from 685–67,500, 1460–50,010, and 2180–29,000 ng/g, respectively. These concentrations were much higher than the medians of PCBs (52–2900 ng/g). BDE 209 and decabromodiphenyl ethane (DBDPE) were the two major halogen flame retardants in dust, while tris-(1-chloro-2-propyl) phosphate (TCIPP) and triphenyl phosphate (TPHP) were the major PFRs. Principle component analysis revealed the different pollutant patterns among different sites. The estimated median human exposures of PBDEs, NBFRs, PFRs, and PCBs via dust ingestion were 1.1–24.1, 0.73–20.3, 1.36–23.5, and 0.04–0.93 ng/kg bw/day for adults, and 16.2–352, 10.7–296, 19.9–343, 0.05–0.61, 0.65–13.6 ng/kg bw/day for toddlers, respectively. Residents from Site 5 had the highest exposure (95 percentile levels and high dust ingestion for toddlers) of PBDEs (3920 ng/kg bw/day), NBFRs (3200 ng/kg bw/day), and PFRs (5280 ng/kg bw/day). More attention should be paid to the contamination with NBFRs and PFRs, instead of PCBs, in these e-waste recycling regions, and local public health threat from PBDE alternatives should remain of concern. To the best of our knowledge, this is the first study on human exposure assessment of PFRs at e-waste sites.

•Short chain chlorinated paraffins (SCCPs) accumulates in aquatic ecosystem.•Waterborne exposure was the main way whereby benthopelagic omnivorous fish accumulated SCCPs.•The liver preferentially accumulated SCCP congeners with higher log KOW.•SCCPs underwent trophic dilution in the aquatic food web.Short chain chlorinated paraffins (SCCPs) are under review for inclusion into the Stockholm Convention on Persistent Organic Pollutants. However, limited information is available on their bioaccumulation and biomagnification in ecosystems, which is hindering evaluation of their ecological and health risks. In the present study, wild aquatic organisms (fish and invertebrates), water, and sediment collected from an enclosed freshwater pond contaminated by electronic waste (e-waste) were analyzed to investigate the bioaccumulation, distribution, and trophic transfer of SCCPs in the aquatic ecosystem. SCCPs were detected in all of the investigated aquatic species at concentrations of 1700–95,000 ng/g lipid weight. The calculated bioaccumulation factors (BAFs) varied from 2.46 to 3.49. The relationship between log BAF and the octanol/water partition coefficient (log KOW) for benthopelagic omnivorous fish species followed the empirical model of bioconcentration, indicating that bioconcentration plays an important role in accumulation of SCCPs. In contrast, the relationship for the benthic carnivorous fish and invertebrates was not consistent with the empirical model of bioconcentration, implying that the bioaccumulation of SCCPs in these species could be more influenced by other complex factors (e.g., habitat and feeding habit). Preferential distribution in the liver rather than in other tissues (e.g., muscle, gills, skin, and kidneys) was noted for the SCCP congeners with higher log KOW, and bioaccumulation pathway (i.e. water or sediment) can affect the tissue distribution of SCCP congeners. SCCPs underwent trophic dilution in the aquatic food web, and the trophic magnification factor (TMF) values of SCCP congener groups significantly correlated with their corresponding log KOW values (p < 0.0001). The present study results improved our understanding on the environmental behavior and fate of SCCPs in aquatic ecosystem.Download high-res image (160KB)Download full-size image

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 fanti 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 fanti 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.Highlights► DP levels in occupationally exposed workers were significantly higher than those in urban residents. ► The females had remarkably higher DP levels and fanti than the males. ► Males have higher metabolic potential for DPs than females. ► Anti-Cl11-DP could be partly formed via in vivo biotransformation in human.

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 fanti 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 fanti 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.Highlights► DP levels in occupationally exposed workers were significantly higher than those in urban residents. ► The females had remarkably higher DP levels and fanti than the males. ► Males have higher metabolic potential for DPs than females. ► Anti-Cl11-DP could be partly formed via in vivo biotransformation in human.

•Halogenated organic pollutants were analyzed in marine fish from the PRE, South China.•DDTs remained the most abundant contaminants in fish (DDTs > PCBs > PBDEs ≈ HCHs > AHFRs).•Decreasing temporal trends were observed for levels of DDTs, PCBs, and PBDEs.•New inputs from diverse sources still exist in the Pearl River Estuary.Dichlorodiphenyltrichloroethane and its metabolites (DDTs), hexachlorocyclohexanes (HCHs), polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs), dechlorane plus (DP), 2,3,5,6-tetrabromo-p-xylene (pTBX) and pentabromotoluene (PBT) were measured in baby croaker (Collichthys lucidus) and mullet (Osteomugil ophuyseni) collected in 2005 and 2013 from the Pearl River Estuary. DDTs, HCHs, PCBs, and PBDEs were detected in two fish species at concentrations of 150–8100, 1.4–120, 22–560, 2.2–280 ng/g lipid wt., respectively. The levels of these chemicals were significantly lower in 2013 than in 2005. The compositions for DDTs, HCHs, and PBDEs in 2013 differed from those in 2005, indicating source changes between the two sampling periods. DP, pTBX and PBT were detected at concentrations of ND–130 ng/g lipid wt. No clear temporal trends were found for these contaminants. Overall, these results indicated the effectiveness of regulations and source controls in substantively reducing inputs of these contaminants to the Pearl River Estuary.