•Low doses of TDP increased cell viability, intracellular Ca2+ and ROS levels.•TDP activated the PI3K/AKT and ERK signaling pathways via GPR30.•GPR30 mediated the TDP-induced cell proliferation.•ERα plays important role in TDP-induced cell proliferation effect.•TDP elicits estrogenic action via cross talk between ERα and GPR30 pathways.Many studies have been shown that environmental estrogen bisphenol A (BPA) can activate nuclear receptor (estrogen receptor alpha, ERα) or membrane receptor (G-protein-coupled receptor, GPR30) in breast cancer cells and exerts genomic or nongenomic actions inducing cell proliferation. 4,4′-thiodiphenol (TDP) as one of BPA derivatives exhibits more potent estrogenic activity than BPA does. However, comparatively little is known about the ways in which TDP interferes with these signaling pathways and produces cell biological changes. This study evaluated the effect of TDP on cell viability, reactive oxygen species (ROS) formation, and intercellular calcium (Ca2+) fluctuation in MCF-7 breast cancer cells. The underlying molecular mechanism of cell proliferation induced by TDP was analyzed by examining the activation of ERα and GPR30-mediated phosphatidylinotidol 3-kinase/protein kinase B (PI3K/AKT) and extracellular-signa1regulated kinase (ERK1/2) signaling pathways. The results showed that exposure to 0.1–10 μM TDP for 24, 48, and 72 h significantly increased viability of MCF-7 cells. At the same concentration range, TDP exposure for 3 and 24 h markedly elevated ROS production and intracellular Ca2+ levels. In addition, 0.01–1 μM TDP significantly increased the expression of ERα, GPR30, p-AKT and p-ERK1/2 protein. Specific protein inhibitors blocked phosphorylation of ERK1/2 and AKT and decreased TDP-induced cell proliferation. These findings show that TDP activated the GPR30-PI3K/AKT and ERK1/2 pathways, and the resulting interaction with ERα stimulated MCF-7 cell proliferation. Our results indicate a novel mechanism through which TDP may exert relevant estrogenic action in ERα positive cancer cells.

A simple method was developed for simultaneous determination of seven urinary metabolites of organophosphate esters (OPs) using liquid chromatography-tandem mass spectrometry (LC-MS/MS). Based on different physical and chemical properties of these OP metabolites, their enrichment and clean-up were performed through solid phase extraction to obtain high-efficient solid phase extraction cartridges, and the washing and elution conditions were optimized. At the same time, the kinetic parameters and mass spectrometry parameters were investigated for getting the qualitative and quantitative characteristic ion pairs for analysis of each metabolites. The results showed that the Oasis WAX solid phase extraction cartridge was suitable for sample enrichment and clean-up, and the optimal elution solvents were 2 mL of 5% ammonia in methanol and 2 mL of methanol. The recoveries of six analytes ranged from 60.5 to 104.0%, whereas the recovery of diethyl phosphate ranged from 17.8% to 36.2%. The complete baseline separations of seven analytes were achieved under optimized chromatographic conditions. The limits of detection and limits of quantification of the seven analytes ranged from 0.005 to 0.2 μg L−1 and 0.02 to 0.5 μg L−1, respectively. The intra-day and inter-day precision results (RSD = 15.4%) showed that this method had good stability and reproducibility. This method was subsequently used to determine OP metabolites in 10 urine samples from the general population in Guangzhou city. The concentrations of the seven OP metabolites in urine samples ranged from 0.5 to 6.7 μg L−1.A simple method was developed for simultaneous determination of seven urinary metabolites of organophosphate esters by solid-phase extraction and liquid chromatography-tandem mass spectrometry (LC-MS/MS).Download high-res image (77KB)Download full-size image

A method was developed for simultaneous determination of multiple persistent organic pollutants (POPs) such as organochlorine pesticides (OCPs), hexabromocyclododecanes (HBCDs), polybrominated diphenyl ethers (PBDEs) and polychlorinated biphenyls (PCBs), in human breast milk. The sample pretreatment procedure included liquid-liquid extraction, gel permeation chromatography (GPC), and solid-phase extraction (SPE) cleanup. Gas chromatography-mass spectrometry (GC-MS), liquid chromatography-tandem mass spectrometry (LC-MS/MS) and gas chromatography-tandem mass spectrometry (GC-MS/MS) were applied in the analysis of target compounds. By using GPC to remove high-molecular-weight lipids and SPE for further cleanup and separation of target compounds, the interferences from the biological matrix could be greatly reduced. The developed sample pretreatment is suitable for multi-component analysis of very low concentrations of POPs in small volume of human samples. The developed method of simultaneous determination of PCBs and OCPs by GC-MS/MS exhibited excellent sensitivity and selectivity. Spiked recoveries were 88.7%–98.8% for PBDEs, 88.5%–92.5% for HBCDs, 67.9%–82.3% for PCBs, and 81.7%–116.1% for OCPs, and limits of detection were 0.13–1.8 ng L−1 for PBDEs, 0.31–1.2 ng L−1 for HBCDs, 0.22–1.4 ng L−1 for PCBs, and 0.20–1.5 ng L−1 for OCPs. This method was applied to the analysis of POPs in 20 human breast milk samples from Weifang City. The result showed that the median concentrations of HBCDs, PBDEs, PCBs, and OCPs were 2.86, 7.76, 8.84 and 643 ng g−1 lipid weight, which were comparable to those in human breast milk samples from populations of other regions in China.A method was developed for the simultaneous determination of multiple persistent organic pollutants (POPs) such as hexabromocyclododecanes (HBCDs), polybrominated diphenyl ethers (PBDEs), polychlorinated biphenyls (PCBs), and organochlorine pesticides (OCPs) in human breast milk. When the samples were cleaned up on a SiO2 solid-phase extraction column, the analytes were separated into two fractions. GC-NIC-MS, GC-EI-MS/MS and LC-ESI-MS/MS were applied in the analysis of target compounds.Download high-res image (103KB)Download full-size image

The concentrations and distribution of polybrominated diphenyl ethers (PBDEs), hexabromocyclododecane (HBCD), and tetrabromobisphenol A (TBBPA) were investigated in 28 sediment samples collected from Taihu Lake, Eastern China. The results showed that all three classes of compounds were detected in 28 sediment samples but that PBDEs were the main contaminants in the study area. The total PBDE concentrations ranged from 3.77 to 347 ng/g dry weight (dw) with a mean value of 72.8 ng/g dw, whereas the concentrations ranged from 0.168 to 2.66 and from 0.012 to 1.30 ng/g dw for HBCD and TBBPA, respectively. In all of the sediment samples, BDE-209 was the predominant congener, accounting for 95.9 to 98.6 % of the total PBDEs, which indicated that commercial mixtures of deca-BDEs were the main sources of PBDE contamination. Higher concentrations of PBDEs were found in samples collected from Meiliang Bay and Gonghu Bay near the inflow river, which suggested that inflow runoff might play an important role in the PBDE levels in Taihu Lake sediments.

A simple and sensitive method was developed for the simultaneous determination of methyl, ethyl, n-propyl, n-butyl, and benzyl parabens in human urine by liquid chromatography coupled with electrospray ionization tandem mass spectrometry (LC-ESI-MS/MS). Enzymatic hydrolysis conditions were optimized to deconjugate the urinary parabens, glucuronide and sulfate conjugates. Solid phase extraction (SPE) was then used for sample clean-up. LC-ESI-MS/MS conditions for sample analysis were also optimized to achieve the maximal sensitivity and accuracy. Parabens were finally separated on a C8 reversed phase column. Correlation coefficients (R2) and recoveries ranged from 0.998 to 0.999 and 80.6% to 95.6%, respectively, and intra-day and inter-day precisions (relative standard deviation, RSD) were within 1.2–4.5% and 2.2–7.1%, respectively. Limits of detection (LODs) for methyl, ethyl, n-propyl, n-butyl, and benzyl parabens were 3, 3, 3, 3, and 1 pg, respectively. The optimized method was successfully used to determine parabens in urine samples from school students in Southern China.

We investigated the effects of hexabromocyclododecanes (HBCDs) at environmentally relevant concentrations on human L02 hepatocytes and explored possible underlying molecular mechanism(s), focusing on functional interactions between the phosphatidylinositol 3-kinase/protein kinase B (PI3K/Akt) and nuclear factor-erythroid 2-related factor 2/antioxidant response element (Nrf2/ARE) pathways. The results showed that low concentrations of HBCDs could stimulate cell proliferation in a “DNA-dependent protein kinase catalytic subunit” (DNA-PKcs)-dependent manner, increase protein levels and nuclear translocation of transcription factor Nrf2, and upregulate expression of its target gene heme oxygenase-1 (HO-1). Electrophoretic mobility-shift assays (EMSAs) showed that ARE was a prominent element for HO-1 induction after low-concentration HBCDs exposure. The relationship between PI3K/Akt pathway and Nrf2/HO-1 axis was demonstrated by the finding that pretreatment with PI3K inhibitors (wortmannin, LY294002) attenuated the upregulation of Nrf2 expression induced by HBCDs exposure. Furthermore, knock-down of DNA-PKcs through small interfering RNA blocked Nrf2/HO-1 axis activation in L02 cells exposed to low-concentration HBCDs. Moreover, DNA-PKcs and phosphorylated Akt at Ser473 proved to be crucial in regulating the Nrf2-ARE pathway. Thus, the PI3K/Akt pathway is essential in regulating Nrf2-ARE pathway activation in L02 cells induced by low-concentration HBCDs.

Polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) and polybrominated dibenzo-p-dioxins and dibenzofurans (PBDD/Fs) in surface sediment samples from Taihu Lake—an important water supply of the Yangtze River Delta, China—were investigated in the present study. Concentrations of PCDD/Fs ranged from 0.91 to 4.8 pg TEQ g−1 dw (mean: 2.9 pg TEQ g−1 dw, TEQ: Toxic Equivalent), which were all higher than the threshold effect level established by interim sediment quality guidelines in Canada (0.85 pg TEQ g−1 dw). The levels of PBDD/Fs ranged from 0.16 to 1.6 pg TEQ g−1 dw (mean: 0.52 pg TEQ g−1 dw) and accounted for 5–33% (mean: 14%) of the total PCDD/Fs and PBDD/Fs TEQ. Comparatively, the abundance of sedimentary PCDD/Fs in the three regions (Meiliang Bay, Gonghu Bay, and Xukou Bay) showed a decreasing trend from the inflow region to the outflow region, while no significant difference was observed among their 2,3,7,8-PBDD/Fs levels, which suggested that the sources of PCDD/Fs and PBDD/Fs differed in this area. Principal component analysis suggested that the historical production/usage of pentachlorophenol and sodium pentachlorophenate was the dominant source of PCDD/Fs in the sediment of these regions. Although the specific sources of PBDD/Fs in the sediment of Taihu Lake were unclear, it was suspected to be due to atmospheric deposition; however, an additional study is needed to confirm this.

Several studies have indicated that mixed brominated/chlorinated organic compounds could be formed during the thermal process such as the incineration of municipal solid waste and open burning of unregulated e-waste at recycling areas. In this study, air particles and soils from e-waste recycling areas, as well as outdoor and indoor air particles from urban Guangzhou, were collected and pooled for the identification of mixed chlorinated/brominated diphenyl ethers (PXDEs). Three monochloro-nonabromo diphenyl ethers (Cl-nonaBDEs), including 6′-Cl-BDE-206, 5′-Cl-BDE-207, and/or 4′-Cl-BDE-208, were first structurally identified in these air and soil samples. The identification was done by comparison of retention times in chromatograms of pure reference compounds and environmental samples, as well as by comparison with full-scan mass spectra data in electron capture negative ionization mode. Because of their similar physical−chemical properties, 4′-Cl-BDE-208 and 5′-Cl-BDE-207 absolutely coeluted, even on a nonpolar DB-5 column. Further investigation is still needed to clarify these findings. Nevertheless, the results indicated that Cl-nonaBDEs would occur in various environmental matrices. Because the replacement of Br by Cl will change the physical−chemical properties of PBDE analogues, environmental occurrence, fate, and transport, the potential toxicity of PXDEs should be investigated.

Hexabromocyclododecanes (HBCDs) are raising concern because of their potential persistence, bioaccumulation, and toxicity. In this study, we investigated the concentrations, diastereoisomer- and enantiomer-specific profiles, and mass inventories of HBCDs in 90 surface soils from two e-waste recycling areas (Qingyuan, Guiyu) and from industrial areas in South China. The mean concentrations of total HBCDs in the surface soils ranged from 0.22 to 0.79 and from 0.31 to 9.99 ng/g dw for two surrounding e-waste recycling sites and industrial areas, respectively. The highest total HBCD concentration (284 ng/g dw) was found at the e-waste recycling site in Qingyuan, while total HBCD levels fell dramatically with increasing distance from the recycling site, suggesting that the e-waste recycling activities were an important source of HBCDs. The diastereoisomer profiles in 75 of the 90 soil samples differed from those of the commercial products. The mean enantiomeric fraction values for α-, β-, and γ-HBCDs in soils ranged from 0.503(0.010) to 0.507(0.003), 0.494(0.003) to 0.506(0.009), and 0.502(0.003) to 0.511(0.006), respectively, suggesting that there was no stereoselective transformation of the three diastereoisomers. The mass inventories of HBCDs gave preliminarily estimates of 3.42 kg and 1.84 tonnes for the e-waste recycling areas and industrial areas, respectively. It is notable that the diasteroisomer and enantiomer profiles of this study failed to distinguish definitely that the isomeric transformation occurred during the product processing or in the environmental matrix. Further laboratory studies on abiotic and biotic transformation are needed to clarify this issue.

A rapid and sensitive method was developed for the determination of eight nitrobenzenes and four nitrochlorobenzenes in water. The method is based on dispersive liquid-liquid microextraction (DLLME) followed by gas chromatography-mass spectrometry (GC-MS). The key factors influencing the extraction efficiencies, including the nature and volume of the extraction and dispersion solvent and the ratios of the extraction solvent and dispersion solvent were examined and optimized. Under the optimized conditions, the method yields a linear correlation at a concentration range of 0.5 μg L−1–500.0 μg L−1 for all the target analytes with correlation coefficients (R2) of 0.9915 to 1.0000, and relative standard deviations (RSD, n = 6) of between 4.9% and 8.2%, depending on the compound analysed. In addition, good pre-concentration factors of 243 to 525 for each specific compound were achieved. These results suggest that the method presented herein is a rapid and powerful microextraction technique that is useful for the detection of these organic pollutants in water samples and is suitable for emergency monitoring.

Di-(2-ethylhexyl) phthalate (DEHP) is a common plasticizer used in industrial and diverse consumer products. Animal studies indicate DEHP caused developmental, reproductive, and hepatic toxicities. However, human studies of the potential effects of DEHP are limited.The exposed site with a history of over 20 years of waste plastic recycling was located in Hunan Province, China. The reference site without known DEHP pollution source was about 50 km far away from the exposed site. In this study, 181 workers working in plastic waste recycling and 160 gender–age matched farmers were recruited. DEHP concentrations in water and cultivated soil samples, serum thyroid-stimulating hormone, malondialdehyde (MDA), superoxide dismutase (SOD), urinary 8-hydroxy-2′-deoxyguanosine (8-OHdG), and micronuclei frequency in human capillary blood lymphocytes were analyzed.Mean levels of DEHP were greater in environment at the recycling site than at reference site (industry wastewater for the exposed: 42.43 μg/l; well water: 14.20 vs. 0.79 μg/l, pond water: 135.68 vs. 0.37 μg/l, cultivated soil: 13.07 vs. 0.81 mg/kg, p < 0.05 for all). The workers had higher median levels of MDA (3.80 vs. 3.14 nmol/ml) and urinary 8-OHdG (340.37 vs. 268.18 μmol/mol creatinine) and decreased SOD activities (112.15 vs. 123.82 U/ml) than the reference group (p < 0.01 for all). Multivariate analysis revealed that the history of working in waste plastic recycling was an independent risk factor for the increased urinary 8-OHdG levels in the male workers (p < 0.01).The occupational DEHP exposure might contribute to oxidative deoxyribonucleic acid damage in the male workers.

Previous studies have reported high serum concentrations of polybrominated diphenyl ethers, especially decabromodiphenyl ether (BDE-209), in the residents of an electronic waste (e-waste) dismantling site in Guiyu town, South China. In the present study, human serum samples in this region were collected and pooled for the identification of hydroxylated diphenyl ethers (OH-PBDEs). Three OH-PBDEs, including two hydroxylated octabromodiphenyl ethers (OH-octaBDEs, 6-OH-BDE196 and 6-OH-BDE199) and one hydroxylated nonabromodiphenyl ether (OH-nonaBDE, 6′-OH-BDE206), were first structurally identified. Identification was done by coeluting a mixture of synthetic authentic standards with the methylated OH-PBDEs from the pooled samples using two gas chromatography columns with different polarities. The results were supported by full scan mass spectrometric data in electron capture negative ionization mode. All three OH-PBDE metabolites had hydroxy groups substituted in the ortho position. These results indicate that hydroxylated higher brominated diphenyl ethers such as OH-octaBDEs and OH-nonaBDEs can accumulate in human blood. The results suggest that higher brominated diphenyl ethers could be oxidatively metabolized into OH-PBDEs in humans. Because low brominated OH-PBDEs can also be detected in abiotic media, further investigations are needed to determine the presence of higher brominated OH-PBDEs in the environment in this region.

In this study, the occurrence and distribution of polycyclic aromatic hydrocarbons (PAHs) were investigated in six sludge samples collected from Guangdong Province, China. Concentrations of PAHs varying from 2,534.1 to 6,926.6 μg kg − 1 (dry sludge) were observed in three municipal wastewater treatment plants with phenanthrene (Phe), fluoranthene, and pyrene being the main compounds. In addition, 682.6 μg kg − 1 PAHs were detected in one sludge sample from a food processing plant, with fluorene, Phe, and chrysene being the main components. No PAHs were detected in sludge samples obtained from two cosmetic plants. The levels and distributional characteristics of PAHs, polychlorinated biphenyls (PCBs), and polycyclic musks (PMs) from the samples were also compared. The results of this comparison indicated that petrochemical refineries and road traffic played important roles in the PAH loads in sludge, while PMs primarily originated from domestic wastewater and industrial wastewater from cosmetic plants. Finally, the presence of 98.8 μg kg − 1 PCBs in sludge suggested diffusional emission sources from electrical components containing PCBs.

Previous studies have reported high serum concentrations of polybrominated diphenyl ethers in residents of an electronic waste (e-waste) dismantling site in Guiyu town, South China. In this study, serum levels of Dechlorane Plus (DP), a chlorinated flame retardant of growing concern, were measured in residents of this region, and compared to those of a matched cohort from a nearby region in Haojiang, where fishing is the dominant industry. DP was detected in all the serum samples, with concentrations ranging from 7.8 to 465 ng/g lipid (median: 42.6 ng/g) and 0.93 to 50.5 ng/g lipid (median: 13.7 ng/g) in Guiyu and Haojiang, respectively. The Pearson’s correlation coefficient between DP and decabromodiphenyl ether showed a positive relationship in Guiyu (r = 0.931, p < 0.01), but no correlation in Haojiang (r = 0.321, p = 0.34). The average anti-DP fractional abundances (fanti ratio) were 0.58 ± 0.11 and 0.64 ± 0.05 for Guiyu and Haojiang, respectively (p < 0.01). Tentatively identified dechlorination product ([−Cl + H]) was found in 19/40 serum samples (11/20 for Guiyu, 8/20 for Haojiang). These results suggest that the Guiyu and Haojiang cohorts experienced different dominant exposure routes. It is also possible that DP could bioaccumulate in a stereoselective manner, and undergo dechlorination metabolism. To the best of our knowledge, this is the first study to report DP levels in human serum. Further studies are needed to confirm the results of this study.

Hexabromocyclododecanes (HBCDs) are ubiquitous contaminants in the environment, but little is known on the occurrence and distribution of HBCDs in the background atmosphere of urban environments. In this study, air samples were collected from four sites in the city of Guangzhou, a typical fast developing metropolitan of South China, for quantifying the concentration levels, diasteroisomer profiles, gas-particle distribution and enantiomeric fractions of HBCDs. The results showed that the measured mean atmospheric HBCD concentrations ranged from 0.69 to 3.09 pg/m3, which were similar to those reported from remote or urban sites of the U.S., but were significantly lower than those of Europe. The analysis on diastereoisomer profiles indicated that α-HBCD (59–68%) was the dominant isomer and β-HBCD was a minor isomer in all air samples, which appeared to be different from commercial products. A large variable percentage of HBCDs (69.1–97.3%) are existed in the particle phase, suggesting that long-range tansport of HBCDs might be occur in some environmental conditions. The results of enantiomeric fractions indicated that β- and γ-HBCD were racemic mixtures in the tested air samples and that (−)-α-HBCD was slightly enriched in the typical urban site, implying that the HBCDs in these studied sites might be a mixture of emissions from both local sources and soil-air exchange.

Breast milk has been widely used as a bioindicator to assess the extent of human exposure to PBDEs via various exposure routes. In this study, 48 breast milk samples were collected from primiparous women in Shanghai city, and 14 PBDEs congeners (BDE-28, − 47, − 99, − 100, − 153, − 154, − 183, − 196, − 197, − 203, − 206, − 207, − 208, and − 209) were quantified using gas chromatography-electron capture negative ionization-mass spectrometry. The mean concentration of total PBDEs was 8.6 ng/g lipid weight, and ranged from 1.8 to 26.7 ng/g lipid weight. These concentration levels were similar to those reported in Europe and Asia, but one order of magnitude lower than those in North America. The congener profiles in this study exhibited a specific pattern in human milk found worldwide, BDE-153 and BDE-28 accounted for a relatively higher proportion of lower brominated BDEs (from tri- to hepta-BDEs), whereas higher brominated BDEs (from octa- to deca-BDEs) contributed more than 70% of the total PBDEs. The Spearman's correlation coefficient among higher brominated BDEs showed a positive relationship, and concentration levels of higher brominated BDEs were statistically different between office workers and housewives. Due to relatively higher proportion of PBDEs from octa- to deca-BDEs were detected, air inhalation and dust ingestion might be the major exposure routes of higher brominated BDEs. Further research is needed to clarify the major exposure route of higher brominated BDEs to humans.Research Highlights► Levels and congener profiles of PBDEs reported in breast milk from Shanghai, China. ► Higher brominated from octa- to deca-BDEs accounted for more than 70% of total PBDEs. ► Air inhalation and dust ingestion might be the major exposure routes. ► Further study should focus on health risk assessment of higher brominated BDEs.

A rapid and sensitive method was developed for the determination of eight nitrobenzenes and four nitrochlorobenzenes in water. The method is based on dispersive liquid-liquid microextraction (DLLME) followed by gas chromatography-mass spectrometry (GC-MS). The key factors influencing the extraction efficiencies, including the nature and volume of the extraction and dispersion solvent and the ratios of the extraction solvent and dispersion solvent were examined and optimized. Under the optimized conditions, the method yields a linear correlation at a concentration range of 0.5 μg L−1–500.0 μg L−1 for all the target analytes with correlation coefficients (R2) of 0.9915 to 1.0000, and relative standard deviations (RSD, n = 6) of between 4.9% and 8.2%, depending on the compound analysed. In addition, good pre-concentration factors of 243 to 525 for each specific compound were achieved. These results suggest that the method presented herein is a rapid and powerful microextraction technique that is useful for the detection of these organic pollutants in water samples and is suitable for emergency monitoring.

A simple and sensitive method was developed for the simultaneous determination of methyl, ethyl, n-propyl, n-butyl, and benzyl parabens in human urine by liquid chromatography coupled with electrospray ionization tandem mass spectrometry (LC-ESI-MS/MS). Enzymatic hydrolysis conditions were optimized to deconjugate the urinary parabens, glucuronide and sulfate conjugates. Solid phase extraction (SPE) was then used for sample clean-up. LC-ESI-MS/MS conditions for sample analysis were also optimized to achieve the maximal sensitivity and accuracy. Parabens were finally separated on a C8 reversed phase column. Correlation coefficients (R2) and recoveries ranged from 0.998 to 0.999 and 80.6% to 95.6%, respectively, and intra-day and inter-day precisions (relative standard deviation, RSD) were within 1.2–4.5% and 2.2–7.1%, respectively. Limits of detection (LODs) for methyl, ethyl, n-propyl, n-butyl, and benzyl parabens were 3, 3, 3, 3, and 1 pg, respectively. The optimized method was successfully used to determine parabens in urine samples from school students in Southern China.