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Attention has been drawn to the associations between PFASs and human cognitive decline. However, knowledge on the occurrence and permeability of PFASs in the brains of patients with cognitive impairment has not been reported. Here, we determined 30 PFASs in paired sera and cerebrospinal fluids (CSFs) from patients with cognitive impairment ( n = 41) and controls without cognitive decline ( n = 18). We revealed similar serum PFAS levels but different CSF PFAS levels, with lower CSF PFOA (median: 0.125 vs 0.303 ng/mL, p < 0.05), yet higher CSF PFOS (0.100 vs 0.052 ng/mL, p < 0.05) in patients than in controls. Blood-brain transfer rates also showed lower R CSF/Serum values for PFOA and higher R CSF/Serum values for PFOS in patients, implying potential heterogeneous associations with cognitive function. The R CSF/Serum values for C4-C14 perfluoroalkyl carboxylates exhibited a U -shape trend with increasing chain length. Logistic regression analyses demonstrated that CSF PFOS levels were linked to the heightened risk of cognitive impairment [odds ratio: 3.22 (1.18-11.8)] but not for serum PFOS. Toxicity inference results based on the Comparative Toxicogenomics Database suggested that PFOS in CSF may have a greater potential to impair human cognition than other PFASs. Our results contribute to a better understanding of brain PFAS exposure and its potential impact on cognitive function.

Human skin wipes from 30 participants, air, dust, and food items were collected from a former electronic waste site in South China to provide a comprehensive understanding of residents' exposure to halogenated flame retardants (HFRs) and polychlorinated biphenyls (PCBs). The total concentration of halogenated organic pollutants (HOPs) in the dust, air, food and skin wipes ranged 240-25000 ng/g, 130-2500 pg/m 3 , 0.08-590 ng/g wet weight, and 69-28000 ng/m 2 , respectively. Wild fish, vegetables, and air were dominated by PCBs, whereas dust, livestock, and poultry were dominated by HFRs. The HOP concentrations were several orders of magnitude higher in local foodstuffs than in market foodstuffs. The chemical composition on the forehead was remarkably different from that on the hand. The importance of different exposure routes depends on the residents' food choices, except decabromodiphenyl ethane (DBDPE). For residents who consumed a 100-foot diet (mainly egg) and local wild fish, diet ingestion overwhelmed other exposure routes, and PCBs were mainly contributed by fish and HFRs by egg. For residents who consumed market food, the dermal absorption of most PCB congeners and dust ingestion of highly brominated flame retardants were relatively prominent. Inhalation was found to be a crucial route for pentabromoethylbenzene (PBEB)., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier Ltd. All rights reserved.)

Poly- and perfluoroalkyl acids (PFAAs) are a large family of widespread contaminants of worldwide concern and well-known as "forever chemicals". Direct emission of PFAAs from the fluorochemical industry is a crucial source of PFAA pollutants in the environment. This study implemented nontarget analysis and comprehensive characterization for a category of new PFAA contaminants, i.e., iodinated PFAAs (IPFAAs), in fluorochemical industry wastewater and relevant contaminated river water by liquid chromatography-high-resolution mass spectrometry with a cascade precursor ion exclusion (PIE) strategy and in-house developed data extraction and processing algorithms. A total of 26 IPFAAs (including 2 isomers of an IPFAA) were found and identified with tentative molecular structures. Semiquantification of the IPFAAs was implemented, and the total concentrations of IPFAAs were 0.16-285.52 and 0.15-0.17 μg/L in wastewater and river water, respectively. The high concentrations in association with the predicted ecotoxicities and environmental behaviors demonstrate that these IPFAAs are worthy of more concern and further in-depth research. The cascade PIE strategy along with the data extraction and processing algorithms can be extended to nontarget analysis for other pollutants beyond IPFAAs. The nontarget identification and characterization outcomes provide new understanding on the environmental occurrence and pollution status of IPFAAs from a comprehensive perspective.

A trophic position (TP) model (TP mix model) that simultaneously considered trophic discrimination factor and β Glu/Phe variations was developed in this study and was first applied to investigate the trophic transfer of halogenated organic pollutants (HOPs) in wetland food webs. The TP mix model characterized the structure of the wetland food web more accurately and significantly improved the reliability of TMF compared to the TP bulk , TP AAs , and TP simmr models, which were calculated based on the methods of stable nitrogen isotope analysis of bulk, traditional AAs-N-CSIA, and weighted β Glu/Phe , respectively. Food source analysis revealed three interlocking food webs (kingfisher, crab, and frogs) in this wetland. The highest HOP biomagnification capacities (TMF mix ) were found in the kingfisher food web (0.24-82.0), followed by the frog (0.08-34.0) and crab (0.56-11.7) food webs. The parabolic trends of TMF mix across combinations of log K OW in the frog food web were distinct from those of aquatic food webs (kingfisher and crab), which may be related to differences in food web composition and HOP bioaccumulation behaviors between aquatic and terrestrial organisms. This study provides a new tool to accurately study the trophic transfer of contaminants in wetlands and terrestrial food webs with diverse species and complex feeding relationships.

Halogenated organic additives (HOAs) are used in plastic components of various electrical products, potentially causing detrimental effects on the eco-environment and humans. Besides reported HOAs, many unknown HOAs may be present in electrical product plastics and urgently require identification and characterization. This study performed nontarget analysis and comprehensive characterization of HOAs in three typical electrical product plastics by nontarget analysis using gas chromatography-negative chemical ionization-high-resolution mass spectrometry in association with in-house-developed chlorine/bromine-specific data-processing algorithms. A total of 674 formulas of HOAs were identified in the plastics dismantled from three electrical products, among which 166, 362, and 146 were organochlorines, organobromines, and mix-chlorinated/brominated organic compounds, respectively. The identified HOAs were semiquantified, and the total concentrations of HOAs in individual plastics were 445-1549 ng/g. Organobromines showed the most species and the highest abundances in all of the plastics, of which the abundances accounted for 86.6-98.0% of the total HOAs. Partial HOAs (209 formulas) were tentatively structurally elucidated, which were classified into 13 groups, i.e., halogenated alkyl phenoxyethyls (H-alkyl phenoxyethyls), H-alkylbenzenes, H-benzenes, H-bisphenol A (H-BPAs), H-dioxins, H-diphenyl ethers, H-biphenyls/terphenyls, H-polycyclic aromatic hydrocarbons, H-phenols, H-phenyl esters, H-phenyl-aldehydes/ketones, H-quinones, and an undefined group containing the HOAs such as dechlorane plus and chlordane. H-BPAs were the predominant HOAs in the plastics, showing relatively high concentrations (13-281 ng/g), and tetrabromobisphenol A was the most abundant H-BPA, with the concentrations of 9-196 ng/g. The comprehensive characterization results represent a holistic picture on the species features and abundance distributions of HOAs in electrical product plastics and provide an inventory of crucial HOAs worthy of concern. HOAs may migrate from plastics and release into the environment and are possibly an important source of halogenated organic pollutants in the environment, thus calling for further investigation and proper regulation.

Samples of Asota caricae (larvae, pupae, and adults) and its host plant leaf (Ficus hispida), larvae of Aloa lactinea, and mixed adult moths were collected from an electronic waste (e-waste) recycling site in south China. Polycyclic aromatic hydrocarbons, polychlorinated biphenyls, and polybrominated diphenyl ethers were found to exhibit concentrations of 420-1300, 100-860, and 7.6-49 ng/g dry weight, respectively. The different chemical compositions among the samples of the three groups indicated that at least two exposure scenarios occurred among the moths in the study area. A complex relationship between bioamplification factors and the octanol-water partition coefficient (log K OW ) was observed during metamorphosis, in which a positive relationship was evident for 5 < log K OW  < 7, whereas an inverse relationship occurred for log K OW values outside of this range. The biomagnification factors (BMFs) calculated from the larvae of Asota caricae to the host plant were negatively correlated with log K OW for all chemicals, differing completely from those obtained in previous studies. However, after metamorphosis, the correlation between BMF and log K OW was found to coincide with that in previous studies. These results indicate that the biotransformation of pollutants in organisms played a key role in determining whether or not biomagnification occurred in organisms and highlight the potential application of the metabolic rate of chemicals in screening-level risk assessments of new chemicals. Environ Toxicol Chem 2022;41:2395-2403. © 2022 SETAC., (© 2022 SETAC.)

Biomagnification of persistent organic pollutants (POPs) is affected by physiochemical properties of POPs and ecological factors of wildlife. In this study, influences on species-specific biomagnification of POPs from aquatic and terrestrial invertebrates to eight songbird species were investigated. The median concentrations of polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers (PBDEs) in birds were 175 to 13 200 ng/g lipid weight (lw) and 62.7 to 3710 ng/g lw, respectively. Diet compositions of different invertebrate taxa for songbird species were quantified by quantitative fatty acid signature analysis. Aquatic insects had more contributions of more hydrophobic POPs, while terrestrial invertebrates had more contributions of less hydrophobic PCBs in songbirds. Biomagnification factors (BMFs) and trophic magnification factors had parabolic relationships with log  K OW and log  K OA . The partition ratios of POPs between bird muscle and air were significantly and positively correlated with log  K OA of POPs, indicating respiratory elimination as an important determinant in biomagnification of POPs in songbirds. In this study, the species-specific biomagnification of POPs in songbird species cannot be explained by stable isotopes of carbon and nitrogen and body parameters of bird species. BMFs of most studied POPs were significantly correlated with proportions of polyunsaturated fatty acids in different species of songbirds.

In this study, surface sediment samples from 173 black-odorous urban rivers in 74 cities of China were investigated regarding the occurrence, spatial distribution, and ecological risk of legacy phthalates (LPs) and alternative plasticizers (APs). The total concentrations of Σ 7 LPs and Σ 6 APs ranged from 0.0035 to 522 μg/g dw (median: 33 μg/g dw; mean: 60 μg/g dw) and from 0.0015 to 16 μg/g dw (median: 16 μg/g dw; mean: 2.2 μg/g dw), respectively. Di(2-ethylhexyl) phthalate (DEHP), di-n-butyl phthalate (DnBP), and di-iso-butyl phthalate (DiBP) were the dominant LPs, and di-iso-decyl phthalate and di-iso-nonylcyclohexane-1,2-dicarboxylate were the dominant APs. The concentrations and compositions of the LPs and APs varied among different sites and regions, implying location-specific use or production of LPs and APs. The pollutant concentrations in southern and central China were higher than those in northern China. Among the seven regions, Northwest China had the lowest concentrations of LPs and APs. This could be related to industry development level, municipal facilities, and population density. Total organic carbon (TOC) was significantly and positively correlated with the pollutant concentrations, implying that TOC could be an important influencing factor for the distribution of LPs and APs in sediments. The risk quotients of DiBP and DnBP in almost all sediment samples were above 1, indicating the high ecological risks to aquatic organisms. Nevertheless, DEHP, di-methyl phthalate, di-ethyl phthalate, and di-n-octyl phthalate showed low or moderate ecological risks for most sampling sites., (Copyright © 2021 Elsevier Ltd. All rights reserved.)

Many studies have reported maternal transfer of organic contaminants in oviparous species, with inconsonant results. Egg-laying sequence and selected maternal tissues may impact on assessment of potential maternal transfer of contaminants. Here, this hypothesis was verified by exposing chickens (Gallus domesticus) to polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs), and dechlorane plus (DPs). Concentrations in eggs laid during exposure exhibited periodic fluctuations (conforming to egg-laying cycles) and a decreasing trend during depuration. Fluctuation patterns of DPs and BDE209 differed from those of other compounds. The PBDE congener profiles in eggs were dominated by BDE209 during exposure and by BDE100 and 153 during depuration. The abundance of PCB congener (CB138) which is recalcitrant to metabolism increased with laying sequence. Maternal transfer potential was negatively correlated (P = 0.0014, R 2  = 0.7874) to the log K OW of chemicals (log K OW >7) when the muscle, heart, lung, or stomach was used. No correlations were found when the liver, fat, kidneys, or intestine was used (log K OW >7), although DPs and BDE209 showed the highest maternal transfer potential. Different fluctuation patterns of DPs and BDE209 in eggs and increased abundance of BDE209 in eggs laid in the initial egg-laying period imply that the liver, fat, kidney, or intestinal tissues could be more appropriate in assessing maternal transfer of the target analytes., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

A partial life cycle test was performed with silkworms ( Bombyx mori) exposed to different levels of halogenated organic pollutants (HOPs). The aims were to investigate the fate of HOPs during metamorphosis and the adverse effects of HOP exposures on silkworm development. Contaminant exposures resulted in decreased body weights, increased development times, and reductions of fecundity in silkworms. Assimilation efficiencies of HOPs decreased with an increasing octanol-water partition coefficient (log K OW ). From the larvae to the pupae stage, bioamplification factors (BAmFs) exhibited concentration-dependent results, in which there was a positive correlation with the log K OW at the high concentrations but no correlation at the low concentrations. From the pupae to the moth stage, BAmFs were linearly negatively correlated with the log K OW for males, but a parabolic correlation with the log K OW was more suitable for females. Regarding reproductive activities, female moths selectively transferred low log K OW HOPs to eggs by the oviposition except for highly halogenated lipophilic pollutants. However, BAmFs of male moths during mating showed no correlation with the log K OW , although highly halogenated lipophilic pollutants had the highest BAmF values. The sex-specific bioamplification processes and special behaviors of highly halogenated lipophilic pollutants deserve further research.

Although isomer-specific bioaccumulation of dechlorane plus (DP) has been addressed in many studies, it remains unclear which factors determine this process and whether biotransformation of DP occurs in organisms. Comparative experiments were conducted in both in vivo and in ovo incubation using hens and eggs to identify the dominant factors determining the bioaccumulation of DP. Hens and fertilized eggs were exposed to DP isomers (syn- and anti-DP) by feeding and spiking, respectively, to investigate absorption, elimination, and metabolism. No significant differences were found between absorption efficiencies of DP isomers in the adult hens. Following first-order kinetics, anti-DP exhibited a slightly longer half-life than syn-DP as well as an elevated anti-DP fraction in laid eggs, thereby suggesting selective enrichment of anti-DP in adult hens. However, chicken embryos metabolized approximately 12% and 28% of the absorbed syn- and anti-DP, respectively, thereby verifying that anti-DP was preferably metabolized. This result indicated that stereo-selective excretion of syn-DP, rather than preferred metabolism of anti-DP, played a more prominent role in isomer-specific bioaccumulation of DP in chickens. Further studies on metabolites of DP are crucial to understanding the fate of DP in organisms., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

To assess the impacts of e-waste regulations on environmental pollution, we built on a previous study from 2010 to investigate the levels and human dietary exposure of halogenated flame retardants (HFRs) in free-range chicken eggs from Baihe village in 2013 and 2016. The concentrations of PBDEs, PBBs, HBCDs, and DBDPE showed a significant decrease (p<0.05) from 2010 to 2013/2016, suggesting the efficacy of regulatory policies. The relative contribution of BDE209 were higher in 2013 and 2016 than in 2010, accounting for 67.8%, 61.4%, and 27.7%, respectively. The concentration ratios of PBB209:PBB153 were much lower in 2013 (1.51) and 2016 (1.32) than in 2010 (29.5). These observed different profiles likely due to the different environmental behaviors of HFRs (e.g. the different atmospheric migration abilities of PBDE congeners and degradation of PBB209). Our exposure estimates suggested high dietary intake of HFRs via home-produced eggs. As for PBDEs, considering the worst situation (highly polluted eggs were consumed), the margin of exposure (MOE) of BDE99 for both adults and children were 1.5 and 0.3 in 2013, and 1.1 and 0.2 in 2016, respectively, which were below 2.5. According to the CONTAM panel, an MOE larger than 2.5 indicates no health concern. Therefore, these MOE values represent a significant potential health concern due to the adverse impacts of PBDEs on human neurodevelopment and fertility., (Copyright © 2018 Elsevier B.V. All rights reserved.)

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 K OW < 8). Common nonlinear correlations between the ratio of larval to adult concentrations and log K OW were observed for all taxa studied. The ratio of concentrations decreased with increasing values of log K OW (log K OW < 6-6.5), then increased (6 < log K OW < 8) and decreased again (log K OW > 8). This result implies that the mechanism that regulates organic pollutants in insects during metamorphosis is common to all the taxa studied.

Polybrominated diphenyl ethers (PBDEs) and polychlorinated biphenyls (PCBs) are the primary toxicants released by electronic waste (e-waste) recycling, but their adverse effects on people working in e-waste recycling or living near e-waste sites have not been studied well. In the present study, the serum concentrations of PBDEs, PCBs, and hydroxylated PCBs, the circulating levels of thyroid hormones (THs), and the mRNA levels of seven TH-regulated genes in peripheral blood leukocytes of e-waste recycling workers were analyzed. The associations of the hormone levels and gene expression with the exposure to these contaminants were examined using multiple linear regression models. There were nearly no associations of the TH levels with PCBs and hydroxylated PCBs, whereas elevated hormone (T 4 and T 3 ) levels were associated with certain lower-brominated BDEs. While not statistically significant, we did observe a negative association between highly brominated PBDE congeners and thyroid-stimulating hormone (TSH) levels in the e-waste workers. The TH-regulated gene expression was more significantly associated with the organohalogen compounds (OHCs) than the TH levels in these workers. The TH-regulated gene expression was significantly associated with certain PCB and hydroxylated PCB congeners. However, the expression of most target genes was suppressed by PBDEs (mostly highly brominated congeners). This is the first evidence of alterations in TH-regulated gene expression in humans exposed to OHCs. Our findings indicated that OHCs may interfere with TH signaling and/or exert TH-like effects, leading to alterations in related gene expression in humans. Further research is needed to investigate the mechanisms of action and associated biological consequences of the gene expression disruption by OHCs., (Copyright © 2017 Elsevier Ltd. All rights reserved.)

To examine the environmental pollution associated with e-waste recycling activities, the concentrations of organohologenated pollutants (OHPs), i.e., short- and medium-chain chlorinated paraffins (SCCPs and MCCPs), polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs), and several other halogenated flame retardants (OHFRs), were investigated in surface particulates from the workshop floors of four major e-waste recycling sites (Taizhou, Guiyu, Dali and Qingyuan) in China. The mean levels of SCCPs, MCCPs, PCBs, PBDEs and OHFRs in surface particulates ranged from 30,000-61,000, 170,000-890,000, 2700-27,000, 52,000-240,000, and 62,000-140,000ng/g dry weight (dw), respectively. OHFRs, including decabromodiphenyl ethane, dechlorane plus, 1,2-bis(2,4,6-tribromophenoxy)ethane, tetrabromobisphenol A, hexabromocyclododecanes, polybrominated biphenyls, hexabromobenzene, pentabromotoluene, and pentabromoethylbenzene, were frequently (>50% detection frequency) detected in surface particulates with mean concentration ranges of 39,000-63,000, 310-2700, 98-16,000, 21,000-56,000, 55-5700, 1700-27,000, 42-1600, 3.2-220, and 5.8-12ng/g dw, respectively. The composition of OHPs varied depend on the e-waste items processing in different regions. Guiyu and Dali were typical sites contaminated by halogenated flame retardants (HFRs) and CPs, respectively, while Qingyuan, and Taizhou were representative PCB-polluted regions. The evidence produced by this preliminary study indicated that electronic devices and plastics may account for the high content of HFRs and the metal products are likely the major source of CPs in these e-waste sites., (Copyright © 2016. Published by Elsevier B.V.)

Organohalogen pollutants (OHPs) including chlorinated paraffins (CPs), polybrominated diphenyl ethers (PBDEs) and other halogenated flame retardants (OHFRs) (dechlorane plus (DP), decabromodiphenyl ethane (DBDPE), 1,2-bis(2,4,6-tribromophenoxy) ethane (BTBPE), hexabromobenzene (HBB), hexabromocyclododecanes (HBCDs) and tetrabromobisphenol A (TBBPA)) originating from an e-waste recycling area in Guiyu, southern China were investigated in chicken and goose eggs. As expected, OHP concentrations were higher in chicken eggs collected from the location (site 1) approaching the e-waste recycling center than from the location (site 2) far from the e-waste recycling center. Also, much higher OHP levels were observed in goose eggs foraging in residential area (site 2) than that in agricultural area (site 1), suggesting a clear habitat dependent OHP bioaccumulation pattern both concerning distance from e-waste activities and type of foraging habitat. Goose eggs exhibited higher short chain chlorinated paraffins (SCCPs) concentrations but lower PBDE and OHFR levels than chicken eggs. The proportion of high brominated PBDEs (hepta-to deca-BDEs) was lower in goose eggs than that in chicken eggs and showed a clear decrease from site 1 to site 2. DP isomeric composition fanti values (the ratio of the anti-DP to the sum of the anti- and syn-DP) in goose eggs were significantly lower than those in chicken eggs (p < 0.001). These differences are likely a reflection of factors such as the species-specific differences in habitat preference and the differing environmental behaviors of the pollutants owing to their inherent properties (such as solubility and vapor pressure). Our findings suggested a high dietary intake of OHPs via home-produced eggs. For BDE99 there is a potential health concern with respect to the current dietary exposure via eggs., (Copyright © 2016. Published by Elsevier Ltd.)

Hair is a promising, non-invasive, human biomonitoring matrix that can provide insight into retrospective and integral exposure to organic pollutants. In the present study, we measured the concentrations of organophosphate flame retardants (PFRs) in hair and serum samples from university students in Guangzhou, China, and compared the PFR concentrations in the female hair segments using paired distal (5~10cm from the root) and proximal (0~5cm from the root) samples. PFRs were not detected in the serum samples. All PFRs except tricresyl phosphate (TMPP) and tri-n-propyl phosphate (TPP) were detected in more than half of all hair samples. The concentrations of total PFRs varied from 10.1 to 604ng/g, with a median of 148ng/g. Tris(chloroisopropyl) phosphate (TCIPP) and tri(2-ethylexyl) phosphate (TEHP) were the predominant PFRs in hair. The concentrations of most PFRs in the distal segments were 1.5~8.6 times higher than those in the proximal segments of the hair (t-test, p<0.05), which may be due to the longer exposure time of the distal segments to external sources. The values of log (PFR concentrations-distal/PFR concentrations-proximal) were positively and significantly correlated with log KOA of PFRs (p<0.05, r=0.68), indicating that PFRs with a higher log KOA tend to accumulate in hair at a higher rate than PFRs with a lower log KOA. Using combined segments of female hair, significantly higher PFR concentrations were observed in female hair than in male hair. In contrast, female hair exhibited significantly lower PFR concentrations than male hair when using the same hair position for both genders (0-5cm from the scalp). The controversial results regarding gender differences in PFRs in hair highlight the importance of segmental analysis when using hair as an indicator of human exposure to PFRs., (Copyright © 2016 Elsevier Inc. All rights reserved.)

Knowledge is limited about the bioaccumulation of persistent halogenated compounds (PHCs) in terrestrial wildlife. Several PHCs, including dichlorodiphenyltrichloroethane (DDT) and its metabolites (designated as DDTs), polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs), decabromodiphenylethane (DBDPE) and 1,2-bis(2,4,6-tribromophenoxy) ethane (BTBPE), and stable isotopes (δ(15)N and δ(13)C) were analyzed in the muscle of four terrestrial passerines, Parus major, Copsychus saularis, Pycnonotus sinensis and Pycnonotus jocosus, from a nature reserve in South China. P. major had the highest PHC concentrations, with median values of 1060, 401, 92, 25 and 0.3 ng/g lipid weight for DDTs, PCBs, PBDEs, DBDPE and BTBPE, respectively. Fractions of DDT in P. jocosus and PCBs 153, 118 and 180 in C. saularis were higher compared with the other species. The inter-species differences in PHC concentrations and profiles could be attributed to the differences in trophic level, diet, living habits and metabolic capacity among the birds., (Copyright © 2015 Elsevier Ltd. All rights reserved.)

Although a number of studies have addressed the bioaccumulation of Dechlorane Plus (DP) flame retardant in wildlife, few data are available on terrestrial organisms. This study examined the presence of DP isomers in the muscle tissue of seven terrestrial resident passerine species, i.e., the great tit (Parus major), the oriental magpie-robin (Copsychus saularis), the red-whiskered bulbul (Pycnonotus jocosus), the light-vented bulbul (Pycnonotus sinensis), the streak-breasted scimitar babbler (Pomatorhinus ruficollis), the long-tailed shrike (Lanius schach), and the orange-headed thrush (Zoothera citrina), from a national nature reserve located in South China. The ∑DP (sum of syn-DP and anti-DP) concentrations ranged from 1.2 to 104 ng/g lipid weight, with significantly higher levels in insectivorous birds than in omnivorous birds. The overall exposure to DP isomers of the current passerines may be attributed to the intensive release of this pollutant from electronic waste recycling sites and industrial zones in the vicinity of the nature reserve. Species-specific DP isomeric profiles were also found, with significantly greater fanti values (the isomer fractions of anti-DP) in the red-whiskered bulbul and the oriental magpie-robin. Additionally, the fanti values were significantly negatively correlated to ∑DP concentrations for the individual bird samples, suggesting the influence of DP concentrations on the isomeric profiles., (Copyright © 2015 Elsevier B.V. All rights reserved.)

Sediments were collected from three mangrove wetlands in the Pearl River Estuary (PRE) of South China to investigate spatial and temporal distributions of polybrominated diphenyl ethers (PBDEs), decabromodiphenyl ethane (DBDPE) and 1,2-bis(2,4,6-tribromophenoxy)ethane (BTBPE). Concentrations of ΣPBDEs, DBDPE and BTBPE in mangrove sediments of the PRE ranged from 1.25-206, 0.364-34.9, and not detected-0.794 ng g(-1) dry weight, respectively. The highest concentrations of ΣPBDEs, DBDPE and BTBPE were found at the mangrove wetland from Shenzhen, followed by Zhuhai and Guangzhou, showing the dependence on the proximity to urban areas. PBDEs were the predominant brominated flame retardants (BFRs) in mangrove sediments. The concentrations of ΣPBDEs, DBDPE and BTBPE in sediment cores showed an increasing trend from the bottom to top layers, reflecting the increasing usage of these BFRs. The inventories of ΣPBDEs, DBDPE and BTBPE in mangrove sediments were 1962, 245, and 4.10 ng cm(-2), respectively. This is the first study to report the occurrence of DBDPE and BTBPE in mangrove ecosystems., (Copyright © 2014 Elsevier Ltd. All rights reserved.)

Several organohalogenated pollutants (OHPs), including polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs), decabromodiphenyl ethane (DBDPE), and 1,2-bis(2,4,6-tribromophenoxy) ethane (BTBPE) were examined in chicken dietary sources (soil and feed) and gastrointestinal contents (chyme, intestinal contents, and feces), and in 11 chicken tissues (liver, muscle, heart, lung, fat, brain, stomach, intestine, ovary/testis, kidney, and serum) from an e-waste recycling site in South China. Elevated levels of OHPs were found in the soil and chicken tissues. Soil was a more important source of OHPs, especially brominated flame retardants, than feed. In general, more-halogenated chemicals were less readily absorbed in the gastrointestinal tract. With the exception of the brain and serum, where lower concentrations occurred, no significant differences in PCBs, PBDEs, and BTBPE were found among the chicken tissues. DBDPE was detected mainly in the stomach, intestine, kidney, and ovary. Compared with the soil, all the tissues had lower proportions of CBs 52 and 101. PBDEs were dominated by BDE 209 in the soil and chicken feed; two different PBDE congener profiles, dominated by both BDE 183 and BDE 209 or dominated by BDE 209 only, were found in the chicken tissues except for the brain. Only BDE 47 or BDE 209 was occasionally detectable in the brain. DBDPE was also found in the brain samples despite its high log Kow values. The blood-brain barrier alters patterns of contaminant composition and results in lower levels of OHPs in the brain., (Copyright © 2014 Elsevier B.V. All rights reserved.)

Thirty-two light-vented bulbuls (Pycnonotus sinensis) were collected from six sampling sites in Guangdong Province, South China to investigate the geographical variation on the occurrence of polychlorinated biphenyls (PCBs), dichlorodiphenyltrichloroethane and its metabolites (DDTs). Concentrations of PCBs and DDTs in the pectoral muscle of light-vented bulbul ranged from 140 to 73,000 ng/g lipid weight (lw) and 12 to 4600 ng/g lw, respectively. PCB concentrations were significantly higher in birds from e-waste site compared to other sampling sites (mean, 18,000 vs 290 ng/g lw, p<0.0001), implying that PCBs mainly came from e-waste recycling activities. No significant differences for DDT levels were observed among the sampling sites (p=0.092). Differences in PCB homologue profiles among the sampling sites were found and can be probably ascribed to different local contamination sources. p,p'-DDE (>80%) was the most abundant component of DDTs in birds. Compositional pattern of DDTs suggested that historical residue was the main source of DDT. The toxic equivalent (TEQ) concentrations had significant positive correlations with PCB concentrations, indicating that elevated PCB levels may have adverse effects on light-vented bulbuls., (Copyright © 2014 Elsevier B.V. All rights reserved.)

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., (Copyright © 2014 Elsevier Ltd. All rights reserved.)

Little information is available on the bioaccumulation of halogenated flame retardants (HFRs) in terrestrial ecosystem. Eggs of light-vented bulbul, yellow-bellied prinia, plain prinia, and dark green white-eye were collected from an ecological station in the Pearl River Delta, South China to investigate the occurrence of polybrominated diphenyl ethers (PBDEs) and several alternative HFRs, including decabromodiphenyl ethane (DBDPE), dechlorane plus (DP), hexabromobenzene (HBB), pentabromoethylbenzene (PBEB), 1,2-bis(2,4,6-tribromophenoxy)ethane (BTBPE), pentabromotoluene (PBT), and 2,3,5,6-tetrabromo-p-xylene (pTBX). Concentrations of PBDEs, DBDPE, DP, HBB, PBEB, BTBPE, PBT, and pTBX ranged from 53-423, 6.1-609, 4.6-268, not detected (nd)-10, nd-1.4, nd-1.7, nd-7.5, and nd-3.2 ng g(-1) lw, respectively. Light-vented bulbul exhibited significantly lower levels of PBDEs, DBDPE, DP, and HBB than other three bird species due to its phytophagy and the other three bird species' insectivores. PBDEs were the predominant HFRs in bird eggs, followed by DBDPE and DP. Significant negative relationship between the fraction of anti-DP and DP concentrations was observed in bird eggs, suggesting that DP levels play an important role in determining the isomeric composition. Anti-Cl11-DP, the dechlorinated products of DP, was found in bird eggs with concentrations ranging from nd to 0.86 ng g(-1) lw and its source is worth further research., (Copyright © 2013 Elsevier Ltd. All rights reserved.)

Concentrations of heavy metals (Cd, Pb, Cu, Zn, and Ni) were measured in the foodstuffs, house dust, underground/drinking water, and soil from an electronic waste (e-waste) area in South China. Elevated concentrations of these potentially toxic metals were observed in the samples but not in drinking water. The health risks for metal exposure via food consumption, dust ingestion, and drinking water were evaluated for local residents. For the average residents in the e-waste area, the non-carcinogenic risks arise predominantly from rice (hazard index=3.3), vegetables (2.2), and house dust (1.9) for adults, while the risks for young children are dominated by house dust (15). Drinking water may provide a negligible contribution to risk. However, local residents who use groundwater as a water supply source are at high non-carcinogenic risk. The potential cancer risks from oral intake of Pb are 8×10(-5) and 3×10(-4) for average adults and children, and thus groundwater would have a great potential to induce cancer (5×10(-4) and 1×10(-3)) in a highly exposed population. The results also reveal that the risk from oral exposure is much higher than the risk from inhalation and dermal contact with house dust., (Copyright © 2013 Elsevier Inc. All rights reserved.)

The Dinghushan Biosphere Reserve is a nature reserve and a site for the study of tropical and subtropical forest ecosystems. Rapid industrialization and intensive electronic waste-recycling activities around the biosphere reserve have resulted in elevated levels of industrial organic contaminants in the local environment that may cause adverse effects on wildlife that inhabits this area. In the present study, polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs), and 2 alternative brominated flame retardants (BFRs)-decabromodiphenyl ethane (DBDPE) and 1,2-bis(2,4,6-tribromophenoxy) ethane (BTBPE)-were investigated in the biosphere reserve and a reference site by using the kingfisher (Alcedo atthis) as a bioindicator. Residue concentrations in kingfishers from the Dinghushan Biosphere Reserve ranged from 490 ng/g to 3000 ng/g, 51 ng/g to 420 ng/g, 0.44 ng/g to 90 ng/g, and 0.04 ng/g to 0.87 ng/g lipid weight for ∑PCBs, ∑PBDEs, DBDPE, and BTBPE, respectively. With the exception of the BTBPE, these levels were 2 to 5 times higher than those detected in kingfishers from the reference site. The contaminant patterns from the biosphere reserve were also different, with larger PCB contributions in comparison with the reference site. The estimated predator-prey biomagnification factors (BMFs) showed that most of the PCB and PBDE congeners and BTBPE were biomagnified in kingfishers from the biosphere reserve. The calculated toxic equivalent quantity (TEQ) concentrations of major coplanar PCB congeners in kingfishers from the biosphere reserve ranged from 18 pg/g to 66 pg/g wet weight, with some of these TEQ concentrations reaching or exceeding the levels known to impair bird reproduction and survival., (Copyright © 2013 SETAC.)

We analyzed the polychlorinated biphenyls (PCBs) in human hair collected from an electronic waste (e-waste) recycling area in southern China and compared their composition profiles and chiral signatures to those of workplace and domestic dust. The PCB concentrations showed significant age dependence in dismantling workers' hair but not in residents' hair. Among residents, PCB concentrations decreased in the following order: elderly people>students>pre-school children>adults. The PCB homologue and congener profiles of the workers' hair were similar to those of the workplace dust. However, the PCB homologue profile of the residents' hair was clearly different from that of the domestic dust. The chiral congener CB95 generally exhibited a racemic or near-racemic composition in both hair and dust, with enantiomer fractions (EFs) ranging from 0.485 to 0.525 in hair and from 0.479 to 0.504 in dust. The EFs of CB132 in dust (0.477-0.513) were closer to a racemic chiral signature than those in hair (0.378-0.521), but this difference was not significant. Our results suggest that the chiral signature of PCBs may be a better tool than the PCB composition profile for identifying the external and internal sources of organic contaminants in human hair. Further measurements of chiral PCB signatures in hair and blood from the same individuals are needed to identify the external and internal sources of PCBs in human hair., (Copyright © 2013 Elsevier Ltd. All rights reserved.)

Dechlorane Plus (DP) isomers were examined in common kingfishers (Alcedo atthis) and their prey fishes collected from an electronic waste (e-waste) recycling site and a reference site in South China, to investigate the possible influence of DP residue levels on the isomeric compositions. ∑DP (sum of syn-DP and anti-DP) concentrations in kingfishers from the e-waste recycling site ranged from 29 to 150 (median of 58) ng/g lipid weight (lw), which were one order of magnitude greater than those from the reference site (median = 3.9 ng/g lw). The isomer fractions of anti-DP (f(anti)) in kingfishers from the e-waste recycling site (mean of 0.65) were significantly smaller than those from the reference site (0.76). Additionally, the f(anti) values were negatively correlated to logarithm of ∑DP concentrations in the kingfishers (r(2) = 0.41, p < 0.0001). These results suggested that DP residue levels could influence its isomeric composition in the piscivorous bird., (Copyright © 2012 Elsevier Ltd. All rights reserved.)

Diastereoisomers and enantiomers of hexabromocyclododecane (HBCD) were determined in muscle and stomach contents of three terrestrial passerine birds from e-waste, urban and rural locations in South China. The highest HBCD concentration was found at the urban site, followed by the e-waste site, suggesting that HBCD was linked to urbanization and industrialization, as well as e-waste recycling activities. Trophic magnification for α-HBCD was observed in the terrestrial food chain. Diastereisomeric pattern in birds showed the predominance of α-isomer, with a minor contribution of γ-isomer. The enantiomeric analysis revealed a preferential enrichment of (-)-α-HBCD and (+)-γ-HBCD. The similarity in enantiomeric fractions of HBCD isomers between muscle and stomach contents of birds suggested that dietary uptake may be responsible for the observed nonracemic distribution of HBCD isomers in the studied birds although in vivo enantioselective biotic processes cannot be ruled out., (Copyright © 2012 Elsevier Ltd. All rights reserved.)

Three regulated halogenated flame retardants (HFRs), i.e., polybrominated diphenyl ethers (PBDEs), polybrominated biphenyls (PBBs) and hexabromocyclododecanes (HBCDs), and several alternative HFRs (AHFRs) including Dechlorane Plus (DP), decabromodiphenyl ethane (DBDPE), and 1,2-bis(2,4,6-tribromophenoxy) ethane (BTBPE), were investigated in the home-produced eggs from three recycling sites and a reference site in an electronic waste (e-waste) recycling region, South China. Mean levels of HFRs in eggs from the recycling sites ranged 2640-14100, 700-1620, 44-350, and 720-3920 ng/g lipid weight for ∑PBDEs, ∑PBBs, ∑HBCDs, and ∑AHFRs, respectively, which were one to two orders of magnitude higher than those examined in the reference site. PBDEs were the predominant HFR in those eggs, with contributions >50% to the total HFRs; followed by PBBs and the AHFRs (contributing 14-22% in average). The α-HBCD was the predominant diastereoisomers of HBCDs, with preferential enrichment of the (-)-enantiomer in most of the eggs; but no significant stereoselective enrichment of the DP isomers was observed in these eggs. The average estimated daily intakes (EDIs) of PBDEs, PBBs, HBCDs, and the AHFRs via eggs from the recycling sites ranged 4200-20000, 1120-2440, 80-490, and 970-4530 ng/day, respectively, which were one to two orders of magnitude higher than those reported from other parts of the world. The potential adverse effects of these HFRs to human health in the e-waste sites should be further investigated. This is the first report on the isomer compositions of DP and the chiral signatures of HBCDs in hen eggs., (Copyright © 2012 Elsevier Ltd. All rights reserved.)

Brominated flame retardants (BFRs) including polybrominated diphenyl ethers (PBDEs), decabromodiphenyl ethane (DBDPE), and 1,2-bis(2,4,6-tribromophenoxy) ethane (BTBPE), were investigated in common kingfishers (Alcedo atthis) and their prey fish from an electronic waste-recycling site in south China. Elevated BFR residues were detected in the kingfishers, with median concentrations of 8,760, 12, and 7.7 ng/g lipid weight for total PBDEs, DBDPE, and BTBPE, respectively. The calculated predator/prey biomagnification factors (BMFs) were greater than unity for most of the investigated PBDE congeners, with relatively higher values for some hexa-, hepta-, and octa-BDEs (e.g., BDEs 153, 183, 196, 197, 202, and 203). The average BMFs ranged 0.10 to 0.77 and 1.90 to 3.60 for DBDPE and BTBPE, respectively. The BMFs for BTBPE were comparable to or even greater than those for some tri- to penta-BDEs in certain predator/prey pairs, indicating potentially high environmental risks of this compound. Significantly higher concentration ratios of BDEs 202 and 207 to BDE 209 were observed in the kingfishers compared with their prey fish, and these ratios were negatively correlated with the logarithm of BDE 209 concentrations in the kingfishers. This may indicate biotransformation of BDE 209 to BDEs 202 and 207 in these birds. This is the first assessment of the biomagnification potentials of DBDPE and BTBPE in a wild piscivorous bird., (Copyright © 2012 SETAC.)

Polybrominated diphenyl ethers (PBDEs), decabromodiphenyl ethane (DBDPE), polybrominated biphenyls (PBBs) and pentabromotoluene (PBT) were investigated in light-vented bulbul (LVB), long-tailed shrike (LTS) and oriental magpie-robin (OMR) collected from seven sampling sites in South China. ∑PBDEs, DBDPE, PBB 153, and PBT levels ranged from 35 to 15,000, no detected (nd)-130, nd-6800, and nd-6.8 ng/g lipid weight, respectively. Positive correlations were found between δ(15)N values and brominated flame retardant (BFR) concentrations. The BFR geographic pattern indicated that PBDEs were linked to e-waste recycling and local industry activities as well as urbanization; PBB 153 was derived from e-waste; DBDPE was mainly come from local industry activities; and no specific source was observed for PBT. PBDE congener profiles were found to be depended on bird species and sampling sites with relatively high abundances of lower brominated congeners in e-waste site and significantly higher abundance of BDE153 in LTS and OMR than in LVB., (Copyright © 2011 Elsevier Ltd. All rights reserved.)

Human hair and indoor dust from urban, e-waste, and rural areas in south China were collected and analyzed for brominated flame retardants (BFRs). BFRs concentrations in hair from occupational e-waste recycling workers were higher than those from non-occupational exposed residents in other sampling areas. Polybrominated diphenyl ethers (PBDEs) and decabromodiphenyl ethane (DBDPE) are two major BFRs in hair samples. The PBDE congener profiles in hair from the e-waste area are different from those from urban and rural areas with relatively higher contribution of lower brominated congeners. DBDPE, instead of BDE209, has become the major BFR in non-e-waste recycling areas. Significant correlations were found between hair level and dust level for DBDPE and BTBPE but not for PBDEs. The different PBDE congener profiles between dust and hair may suggest that exogenous exposure to the PBDE adsorbed on dust is not a major source of hair PBDEs., (Copyright © 2011 Elsevier Ltd. All rights reserved.)

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.

Purpose: 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 (δ (15)N), 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., Materials and Methods: 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., Results and Discussion: 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., Recommendations and Perspectives: 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.

With the phaseout of brominated flame retardants (BFRs) polybrominated diphenyl ethers (PBDEs), some non-PBDE BFRs have prompted to be alternatives to the discontinued PBDEs. To assess the bioaccumulation potential of these chemicals, field bioaccumulation factors (BAFs) for several non-PBDE BFRs including hexabromocyclododecanes (HBCDs), 1,2-bis(2,4,6-tribromophenoxy)ethane (BTBPE), pentabromotoluene (PBT), pentabromoethylbenzene (PBEB), and hexabromobenzene (HBB), were determined in the aquatic species from a natural pond in an electronic waste recycling site in South China. The log BAFs ranged 2.58-6.01, 3.24-5.58, 3.44-5.98, 2.85-5.98, 3.32-6.08, 2.04-4.77, 2.72-4.09 and 3.31-5.54 for α-HBCD, β-HBCD, γ-HBCD, ∑HBCDs, BTBPE, PBT, PBEB, and HBB, respectively. The log BAF values for HBCD isomers, BTBPE, and HBB were greater than 3.7 (corresponding BAF value 5000) in most of the investigated species, demonstrating their highly bioaccumulative properties. α-, β-, and γ-HBCDs, BTBPE, and HBB appeared comparable or had even greater BAFs compared to PBDE congeners with similar K(OW), suggesting that these BFRs may have a potentially high environmental risk. The BAFs for the given BFR compound were largely variable between species, due to the species-specific feeding ecology, trophic level, and metabolic capacity for these pollutants. Positive linear relationships between log BAF and log K(OW) (r² = 0.59, p = 0.04), and molecular weight (r² = 0.54, p = 0.06) of non-PBDE BFRs were observed in the species with low trophic level (Chinese mysterysnail), suggesting that the chemical's physicochemical properties also played key roles in the bioaccumulation processes., (Copyright © 2010 Elsevier Ltd. All rights reserved.)

Dechlorane Plus (DP) and a dechlorination product, 1,6,7,8,9,14,15,16,17,17,18-octadeca-7,15-diene (anti-Cl(11)-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-Cl(11)-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 (f(anti) 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 f(anti) 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-Cl(11)-DP and anti-DP for both hair and dust samples with similar regression line slopes. The ratios of anti-Cl(11)-DP to anti-DP between hair and dust show no significant difference. These results suggest that anti-Cl(11)-DP in the human body is likely accumulated from the environmental matrix and not formed from biotransformation of the parent DP.

The concentrations of hexachlorocyclohexane (HCHs), dichlorodiphenyltrichloroethane (DDTs), and polybrominated diphenyl ethers (PBDEs) in muscle, liver and brain of ducks from Baiyangdian Lake were determined by gas chromatography coupled with mass spectrometer (GC/MS). The results showed that the concentrations of HCHs, DDTs and PBDEs in various tissues of ducks were in the range of 0.9-5.0 ng/g wet weight (WW), 0.3-2.8 ng/g (WW) and 0.03-0.65 ng/g (WW), respectively. Statistical analysis indicated that the accumulation of DDTs and PBDEs in muscle, liver and brain was significantly different (p < 0.05), but not with HCHs (p > 0.05). Liver tissues contained the highest DDTs and PBDEs levels, with average concentrations of 2.3 ng/g (WW) and 0.37 ng/g (WW), respectively. Among the HCH isomers and DDT metabolites, beta-HCH was the predominant isomers in liver and brain tissues, and p,p'-DDE was the dominant metabolites of DDTs in various tissues. Among the PBDE congeners, BDE47 and BDE99 were the predominant in various tissues. The different profiles of persistent organohalogen compounds in various tissues of ducks may reflect that the Baiyangdian Lake still subject to the contamination of historically residue for HCHs and DDTs. In addition, the source of PBDEs was partly attributed to the industrial pollution, chemical plants, and sewage discharging.

Polybrominated diphenyl ethers (PBDEs) were determined in a sediment core collected from a reservoir in an electronic waste (e-waste) area of South China. PBDEs were detected throughout the core,with a mean value of 9.26 ng/g dry weight. 0.43 to 141 ng/g PBDEs concentrations were low (0.43-2.30 ng/g) and varied less in the lower layers (below 16 cm) of the core,whereas their concentrations increased remarkably in the upper layers (2.90-141 ng/g). The vertical distribution of PBDEs indicated the influence of local e-waste recycling activities. PBDEs originated from commercial deca-BDE mixture were the dominant congeners, accounting for 79.6% of the total PBDEs, followed by PBDEs from penta-BDEs (14.7%). PBDEs from octa-BDEs contributed only 5.69%. The difference between PBDE congener profiles in the sediment and those in the commercial penta-, octa-, and deca-BDEs suggests the possible degradation of highly brominated PBDEs in the sediment, which was further supported by the occurrence of BDE202 and the vertical variation of the fractions of nona-BDE congeners and ratios of BDE197/BDE201. However, more work is needed regarding PBDE degradation in the environment.

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.

Brominated flame retardants (BFRs) were examined in house dust from the electronic waste (e-waste) recycling and urban areas of South China. The concentrations of polybrominated diphenyl ethers (PBDEs) were in the range of 227-160,000 ng/g in the e-waste recycling area and 530-44,000 ng/g in the urban area. These values were much higher than other BFRs, except for novel decabromodiphenyl ethane (DBDPE) whose value of 100-47,000 ng/g was dominant in approximately 1/4 of the samples from the urban area. Urban dust PBDE levels were generally higher than those in many European and Asian countries and comparable to the values found in North America. Urban dust DBDPE levels were higher than those of other areas in the world. The distinct dust BFR profiles observed in the two studied areas were reflective of activities in these areas (electronics industry vs. e-waste recycling). The presence of BDE202, as well as the BDE197 to BDE201 and the nona-BDEs to deca-BDE ratios in the dust samples from the studied areas were probably indicative of environmental degradation of deca-BDE. The estimated daily intakes (EDIs) of average adult and toddler via house dust ranged from 37.0 to 304 ng/day for PBDEs and from 3.01 to 87.6 ng/day for all other BFRs in the studied areas. The EDIs via house dust were much higher than those via other indoor pathways (air, fish, human milk, and toys). Despite the potentially low deleterious risk of PBDE exposure via house dust as suggested by the hazard quotients, this exposure pathway should be of great concern because of the higher BFR exposures for children and the presence of other BFRs (such as DBDPE) which have not yet been fully investigated., (Copyright 2010 Elsevier Ltd. All rights reserved.)

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.

The objective of this study is to illuminate the mechanism of biodegradation of triphenyltin (TPhT). The removal of TPhT by Klebsiella pneumoniae was, therefore, investigated through characteristics studies. The influences of the various parameters were also discussed. The results demonstrated that the cell, extracellular secretion and intracellular enzyme were the effective biomasses for the biodegradation of TPhT. At initial concentration of 3 mg x L(-1), 10.9%, 5.3% and 47.9% of TPhT could be degraded by these biomasses respectively at 30 degrees C within 2 hours under an rotary shaker at 120 r x min(-1). The experimental results also showed that the enzyme activity could be affected by the buffers, pH, temperature, metals and the concentration of TPhT. The degradation efficiency would reach the highest point at pH 8, and at the optimal temperature of 50 degrees C. Metals including Mg2+, Mn2+, Fe2+ and Fe3+ improved the enzyme activity at certain concentrations. In the presence of 15 mg x L(-1) of Mg2+, the removal percentage of TPhT was up to 73.8%. It suggested that the metals activated the enzyme and interacted with the TPhT enabling its removal during the biodegradation process. Linear plots of removal ratios versus concentrations of TPhT meant that the biodegradation fitted the Michaelis-Menten model. The Vmax and Km of this biodegradation were 0. 15 mg x (L x min)(-1) and 47.1 mg x L(-1), respectively.

The biosorption and biodegradation of triphenyltin (TPhT) from aqueous solutions by isolated strains were investigated through microbial separation and characteristic studies. The results illuminated that Klebsiella pneumoniae was an effective strain for the biosorption and removal of TPhT. 70% to 97.9% of TPhT with initial concentration of 3 mg x L(-1) could be absorbed within 2 h, and 26.4% to 54.6% of this TPhT was biodegraded within 5 d using 0.3 g x L(-1) to 3.0 g x L(-1) biomass of K. pneumoniae. TPhT could be more effectively degraded by separated endoenzyme than by cell biomass,and 28.1% to 77.8% of TPhT would be degraded by this way within 2.0 h.The biodegradation experiments also showed that the degradation of TPhT by K. pneumoniae mainly occurred intracellularly and the increase of degradation rate gradually slowed down with time. Separated endoenzyme gave rise to the highest biodegradation of TPhT at the contact time of 2.0 h,while the intact cell achieved the highest rate of biodegradation within 1 d, and then reached a plateau among 2 d to 5 d. The experiments also revealed that the biodegradation process of TPhT included biosorption by cell wall, active transportation across cell membrane, and biodegradation within cytoplasm, in which TPhT bio-adsorbed oh the cell wall increased linearly with time,TPhT inside the cell wall decreased rapidly from 55.9% to 17.0% during the first 3 d, and then turned to smooth; while TPhT in the supernate changed reversely with that occurred inside the cell wall.

Environmental pollutants are suspected to be a cause of global declines in amphibian populations, but few data are available on the bioaccumulation of polybrominated diphenyl ethers (PBDEs) in amphibians. To examine the tissue distribution, biomagnification potential, and maternal transfer of PBDEs in frogs, eighteen PBDE congeners were measured in the muscle, liver, and egg tissues of rice frogs (Rana limnocharis) and insects collected from an electronic waste (e-waste) recycling site in South China. PBDE levels in the frogs ranged from 0.63 to 11.6, 4.57 to 56.2, and 10.7 to 125 ng/g wet wt in the muscles, livers, and eggs, respectively. The frogs exhibited a unique congener profile, compared to those in aquatic and terrestrial species, with BDEs 99, 153, 183, 209, and 47 as the dominant congeners, intermediating between aquatic and terrestrial species. Most of the PBDE congeners in general showed higher affinity to liver than to muscle tissue. Except for BDEs 28, 47, 66, 138, and 206, the average biomagnification factors (BMFs) for all PBDE congeners were greater than 1.0, providing clear evidence of their biomagnification from insects to frogs. A parabolic relationship between log BMFs and bromine atom numbers or log Kow of PBDEs was observed, with the maximum BMF values for PBDEs with 6 bromine atoms (or at a log K(ow) of approximately 8.0). Relatively higher levels of 3-MeO-BDE 47 were found in male frogs, suggesting that male frogs in the present study might have higher metabolic capacity for PBDEs compared to female frogs. The ratio of levels in egg/female liver, indicating mother-to-egg transfer capacity, increased with increasing bromine atom numbers up to 7 and then declined as the bromine atom numbers rose. This indicated that the physicochemical properties of the congeners (e.g., K(ow), molecular sizes, and structures), resulting in different affinities to transport proteins, might impact their maternal transfer in frogs.

The concentrations of three currently used non-polybrominated diphenyl ether (PBDE) brominated flame retardants (BFRs), 1,2-bis(2,4,6-tribromophenoxy)ethane (BTBPE), decabromodiphenyl ethane (DBDPE), and tetrabromobisphenol A bis (2,3-dibromopropyl ether) (TBBPA-DBPE), were examined in environmental and biota samples collected from the Pearl River Delta (PRD) and an electronic waste (e-waste) area in southern China. We also examined deca-BDE (decabromodiphenyl ether) and nine tri- through hepta-BDE congeners for comparison. The results indicate that these non-PBDE BFRs occur widely in the environment of the two study areas. We found a noticeable increase in the levels of TBBPA-DBPE and DBDPE in recent sediments, the concentrations of which even exceed those of BDE209 (deca-BDE) in some samples from the PRD. The BFR profiles of the two study areas are distinct. Relatively high proportions of DBDPE and TBBPA-DBPE were found in the PRD environment, whereas the levels of discontinued BFRs (penta-BDEs and BDE183) and BTBPE were higher in the e-waste area. Our results suggest that the industrial activities in the PRD and the recycling of e-waste have introduced distinct types of BFR contamination to the ambient environment and deca-BDE product has been partly replaced by the TBBPA-DBPE and DBDPE in the PRD. Furthermore, BTBPE and DBDPE were detected in bird tissues and BTBPE in the fish tissues collected from the e-waste area. This is the first report of the occurrence of TBBPA-DBPE in environmental samples worldwide. More studies are needed for reaching a better understanding of the behavior, bioaccumulation, and toxicology of these increasingly used BFRs in the environment.

The present study analyzed road soils collected near the dismantling workshops of an e-waste recycling region in South China to determine the PBDE profiles. Farmland soils at a distance of about 2 km from the dismantling workshops were also collected to evaluate the potential dispersion and deposition of PBDEs in the surrounding environment. Total PBDE concentrations ranged from 191 to 9156 ng/g dry weight in road soils and from 2.9 to 207 ng/g dry weight in farmland soils, respectively. Three PBDE source profiles were observed from the road soils by principal component analysis, and were compared with the congener patterns in different technical products. Elevated abundances of octa- and nona-congeners were found in the "deca-" derived PBDEs as compared with the deca-BDE products. The results in this study suggest that debromination of BDE 209 may have occurred during the use of electric and electronic equipment and/or another technical formulation (Bromkal 79-8DE) was also likely the source of octa- and nona-congeners in e-wastes. Comparison of the PBDE patterns in road and farmland soils implied that the PBDEs in farmland soils have been subject to complex environmental processes.

Polybrominated diphenyl ethers (PBDEs) were analyzed in three invertebrate species, five fish species with different living and feeding habits, and surface sediments collected from the Pearl River Estuary, South China. The concentrations of 10 PBDE congeners (BDEs 28, 47, 66, 99, 100, 85, 154, 153, 138, and 183) ranged from 34.1 to 444.5 ng/g lipid and from 9.88 to 39.0 ng/g organic carbon in biota and sediment samples, respectively. In sediments and some biota samples, BDE 209 was found as the major congener, ranging from nondetectable to 623.5 ng/g lipid in biota samples and from 792 to 4,137 ng/g organic carbon in sediment samples. Different levels of PBDEs in various biota species were attributed to the different feeding habits of the aquatic species or their ability to metabolize PBDE. Different congener profiles between the biota and sediment samples were observed and attributed to the bioaccumulation potential or the ability to metabolize individual BDE congeners. Polybrominated diphenyl ether levels in the biota from the Pearl River Estuary correlated well with lipid contents but did not correlate with the biota lengths. The distribution of biota-sediment accumulation factors for individual PBDE congeners was consistent with the general pattern predicted from a widely used bioaccumulation model.

Concentrations of persistent halogenated hydrocarbons (PHHs) were determined in 13 consumer fish species (a total of 390 individuals) collected from a major fish-farming region of China. The potential health risks of PHHs associated with consumption of fish from China was also systematically assessed regionally and globally. In all fish samples, DDTs, HCHs, PCBs, and PBDEs were the predominant PHH residues, with the median levels (ranges) being 6.0 (0.14-698.9), 0.50 (0.13-24.06), 0.10 (< 0.02-7.65), and 0.15 (< 0.0012-3.85) ng/g wet weight, respectively. The upper-bound (90th percentile) values of estimated daily intakes of DDT, HCHs, PCBs, and PBDEs via fish consumption were 45.5, 1.35, 0.46, and 0.30 ng/kg bw/d (urban), and 15.9, 0.47, 0.16, and 0.10 ng/kg bw/d (rural). Globally, the upper-bound outflows via fishery exportation of DDT, HCHs, PCBs, and PBDEs were 185, 5.51, 1.86, and 1.22 kg, respectively, in 2005. Japan was the largest recipient of PHHs, followed by Korea and the United States. Fish consumption assessments indicated that consumption of freshwater farmed and wild marine fish generally does not subject consumers to significant health risk as far as PHHs are concerned, while limited consumption of seawater farmed fish is advised.