Ying Xu

Electronic and electrical waste(E-waste) is a waste type consisting of any broken or unwanted electrical or electronic appliance.Obsolete E-waste has become a serious problem.Many previous studies showed that persistent organic pollutants(POPs) and heavy metals caused serious contamination in air,soil,sediment and freshwater.It is drawing more and more attentions because of its adverse impacts on environment and human health.According to the State Environmental Protection Administration of China,70% of worldwide e-waste has been sent to China.Taizhou region in Zhejiang Province is one of the most intensive E-waste processing sites in China.Polychlorinated biphenyls(PCBs) were widely used worldwide as coolants and insulators in electrical capacitors and transformers,and as plasticizers in paint and rubber sealant.Large quantities of PCBs have since entered the environment through leakage,disposal,and evaporation.PCBs stability is also responsible for their continued presence in the environment even decades.Environmental levels of PCBs are traditionally measured as total PCB based on Aroclor equivalent analysis,as opposed to congener-specific concentrations,due to analytical limitations and/or cost differentials.To evaluate the true risk of PCBs to human and ecosystem health,more complex and,in turn,costly Dioxin-Like PCB-specific analytical methods(e.g.,U.S.EPA method 1668a) are available.Dioxin-like PCBs(dl-PCBs) are a group of 12 PCBs that share a common toxic mechanism with the most toxic dioxin compound(i.e.,2,3,7,8-tetrachlorodibenzop-dioxin or 2,3,7,8-TCDD) and generally are among the most toxic PCB congeners as they incur toxic effects at relatively lower concentrations than those of non-dl-PCBs.In the present study,samples of winkle,loach and crucian carp were collected from the e-waste area(Taizhou,Zhejing) in 2006.Dl-PCBs were determined in the samples using isotope dilution Gas Chromatography/Mass Spectrometry(GC/MS) method.Our results showed that the average concentrations of PCBs were 1303.53,3845.00 and 5645.34 ng/g lipid weight in winkle,loach and crucian carp,respectively.Toxic equivalencies(TEQs) were determined to be 1.35,8.44 and 29.18 pg WHO-TEQ/g wet weight in winkle,loach and crucian carp,respectively.TEQs in winkle and crucian carp exceed the European maximum permissible level(2006) of TEQs in fish for human food.In addition,PCB 118 was major congener and constituted 57.73%— 61.22% and 44.27%— 50.61% of total PCBs and TEQs,respectively.Furthermore,PCB 118 was found to have linear correlations to the total PCBs and TEQs.The correlative coefficients(R2) were 0.9988(P<0.0001) and 0.9873(P<0.0001).These results indicated that aquatic organisms from the e-waste area have been seriously contaminated by PCBs which might come from Aroclor 1254 released from E-waste dismantling.

Present in the excrement of humans and animals, 17β-estradiol (E₂) has been detected in the aquatic environment in a range from several nanograms to several hundred nanograms per liter. In this study, the sensitivities of rare minnows during different life stages to E₂ at environmentally relevant (5, 25, and 100 ng l⁻¹) and high (1000 ng l⁻¹) concentrations were compared using vitellogenin (VTG) and gonad development as biomarkers under semistatic conditions. After 21 days of exposure, VTG concentrations in whole-body homogenates were analyzed; the results indicated that the lowest observed effective concentration for VTG induction was 25 ng l⁻¹ E₂ in the adult stage, but 100 ng l⁻¹ E₂ in the larval and juvenile stages. After exposure in the early life stage, the larval and juvenile fish were transferred to clean water until gonad maturation. No significant difference in VTG induction was found between the exposure and control groups in the adults. However, a markedly increased proportion of females and appearance of hermaphrodism were observed in the juvenile-stage group exposed to 25 ng l⁻¹ E₂. These results showed that VTG induction in the adult stage is more sensitive than in larval and juvenile stages following exposure to E₂. The juvenile stage may be the critical period of gonad development. Sex ratio could be a sensitive biomarker indicating exposure to xenoestrogens in early-life-stage subchronic exposure tests. The results of this study provide useful information for selecting sensitive biomarkers properly in aquatic toxicology testing.

Yangtze finless porpoise (Neophocaena phocaenoides asiaeorientalis), a protected endangered species, is the sole freshwater subspecies of finless porpoise, living only in the middle and lower reaches of the Yangtze River, China, and its appended lakes. Its population has decreased sharply to 1,400 because of human activities, including environmental contamination. In the present study, polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs), and polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) were determined in the blubber, liver, kidney, stomach, small intestine, and brains of five individual Yangtze finless porpoises collected from 1998 to 2004. The results showed PCB concentrations ranged from 0.06 to 1.89 μg/g lipid weight in the organs and consisted mainly of penta-, hexa-, and decachlorinated biphenyls. The PBDE concentrations were between 5.32 and 72.76 ng/g lipid weight. Tetra-, penta-, and hexabrominated diphenyl ethers were the major homologues. The PCDD/F concentrations ranged from 65 to 1,563 pg/g lipid weight, and their predominant homologues were penta- and hexachlorinated dibenzofurans and hepta- and octachlorinated dibenzo-p-dioxins. The hazard quotients (HQs) based on toxic equivalency were determined to be greater than one in all individuals for PCBs, for PCDD/Fs, and for PCBs and PCDD/Fs In addition, HQs would be higher if PBDEs were included. The results suggest that reduction of environmental contamination may contribute greatly to protecting this highly endangered species.

Polybrominated diphenyl ethers (PBDEs) have been detected for the first time at a range from 231.58 to 685.61 ng g⁻¹lipid weight in the muscles of tilapia (Oreochromis mossambicus) collected from O'ahu, an island of the geographically isolated Hawaiian archipelago.

As the active metabolites of polychlorinated biphenyl (PCBs), hydroxylated polychlorinated biphenyls (OH-PCBs) are found in wildlife and human tissues. They have been proposed as main contributors for endocrine disruption of PCBs in living organisms. In this study, mono-ortho PCB 156 and its hydroxylated metabolites 4′-OH-PCB 159, 4′-OH-PCB 121, and 4′-OH-PCB 72 were selected to investigate the toxic effects on rat hepatoma H4IIE cell line and rat thyroid follicle FRTL-5 cell line at concentrations of 1, 102, 104 nM. 7-Ethoxyresorufin-O-deethylase (EROD) and 7-pentoxyresorufin-O-dealkylase (PROD) activities were determined with micro-EROD/PROD to indicate cytochrome P4501A1 (CYP1A1) and cytochrome P4502B (CYP2B) induction in the H4IIE cell after exposure for 72 h. To assess thyroid disruption of these compounds, thyroglobulin concentrations also were detected inside FRTL-5 cell with immunocellularchemistry and in its medium with radioimmunoassay after exposure for 24 h. Significant inductions of EROD activity by PCB156 at 102 and 104 nM (p < 0.05) were observed, but no effects by the three OH-PCBs in H4IIE cell line. 7-Pentoxyresorufin-O-dealkylase activities were induced only by 104 nM of PCB156 and the three OH-PCBs (p < 0.05). Meanwhile, significant increases of thyroglobulin concentrations were observed in the medium of FRTL-5 cell exposed to 4′-OH-PCB 121 and 4′-OH-PCB 72 at all of the test concentrations (p < 0.05), but not to the other compounds. The results demonstrated that mono-ortho PCBs mainly could be metabolized to hydroxylated metabolites through CYP1A1 instead of CYP2B. Moreover, after being metabolized, OH-PCBs still sustained the ability to induce PROD activity and did exhibit the disruption on thyroglobulin synthesis/excretion in rat cells.

The seasonal variations of estrogenic compounds and the estrogenicities of influent and effluent were investigated by chemical analysis and in vitro assay in a municipal sewage treatment plant in Wuhan (China). The levels of eight estrogenic compounds, including 17β-estradiol (E2), estrone (E1), estriol (E3), diethylstilbestrol (DES), 17α-ethinylestradiol, nonylphenol (NP), 4-tert-octylphenol (OP), and bisphenol A (BPA), were measured by gas chromatography–mass spectrometry. Total estrogenic activity of sewage was quantitatively assessed using primary cultured hepatocytes of male Megalobrama amblycephala Yih using vitellogenin as a biomarker. The E2 equivalents (EEQs) obtained from the chemical analysis were consistent with those measured by bioassay. The natural (E1, E2, and E3) and synthetic (DES) estrogens, as well as NP, were the main contributors of the total EEQs of influent and effluent in the present study. The levels of natural estrogens E1 and E3 in the influent and effluent were higher in winter than in summer, whereas the situation for NP and OP was the reverse. The levels of E2, DES, and BPA varied little among different seasons. 17α-Ethinylestradiol was not detected in the influent and effluent. The estrogenicities of the influent and of the primary and secondary effluents were all higher in summer than in winter. Estrogenic activities in winter mainly originated from natural (E1, E2, and E3) and synthetic (DES) estrogens, whereas the increase of EEQs in summer was contributed by NP. The results from chemical analysis and bioassay demonstrate that estrogenic compounds cannot be entirely removed by the existing sewage treatment process, which should be further improved to protect aquatic ecosystems and human health.

In the present study, female Chinese rare minnows (Gobiocypris rarus) were used as in vivo models and exposed to nonylphenol (NP) at concentrations of 1 to 200 μg/L for 21 d under semistatic conditions. Molecular biomarkers of oxidative stress were measured in unfertilized eggs and included reactive oxygen species (ROS), lipid peroxidation products (thiobarbituric acid-reactive substances [TBARS] and protein carbonyl), superoxide dismutase activity, and glutathione. Cathepsin D activity as an indicator of egg viability also was assayed. Nonylphenol induced ROS formation in unfertilized eggs in all exposed groups compared to the controls. The levels of protein carbonyl and TBARS in unfertilized eggs were significantly increased (p < 0.05) at 10 to 200 and 100 to 200 μg/L, respectively. Good positive correlations were shown between ROS induction and levels of TBARS and protein carbonyl in eggs (R = 0.918, p < 0.05 and R = 0.784, p < 0.05, respectively). Superoxide dismutase activity in eggs was significantly inhibited (p < 0.05) in the 50 to 200 μg/L exposure groups. Glutathione levels in eggs were significantly depleted (p < 0.05) at 100 to 200 μg/L concentrations. In addition, ROS induction resulted in oxidative damage to lipid and protein in chorions. Significant reductions (p < 0.05) of the protein and lipid contents in chorions were both found in the 50 to 200 μg/L exposure groups. A previous study found that NP exposure could lead to chorion thinning in zebra fish. Thus, the reductions in protein and lipid contents in chorion could be the reason for chorion thinning by NP exposure. Meanwhile, cathepsin D activity was significantly inhibited (p < 0.05) in all exposure groups. The results demonstrated that NP-induced oxidative stress could damage the chorion of unfertilized eggs and lead to a decline in gamete quality in female Chinese rare minnow.

The dibenzofuran (DF)-degrading bacterium, Janibacter terrae strain XJ-1, was isolated from sediment from East Lake in Wuhan, China. This strain grows aerobically on DF as the sole source of carbon and energy; it has a doubling time of 12 hours at 30°C; and it almost completely degraded 100 mg/L⁻¹ DF in 5 days, producing 2,2′,3-trihydroxybiphenyl, salicylic acid, gentisic acid, and other metabolites. The dbdA (DF dioxygenase) gene cluster in the strain is almost identical to that on a large plasmid in Terrabacter sp. YK3. Unlike Janibacter sp. strain YY-1, XJ-1 accumulates gentisic acid rather than catechol as a final product of DF degradation.