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91.
Marine mussels, Perna viridis, were transplanted from a reference site to various polluted sites around Hong Kong. After 30 d of exposure, antioxidative responses in the gills and hepatopancreas and tissue concentrations of chlorinated hydrocarbons [polychlorinated biphenyls (PCBs) and chlorinated pesticides (CPs)] were determined for individual mussels. Glutathione S transferase (GST) and glutathione (GSH) were positively correlated with tissue PCB concentrations. Only one of the enzymatic antioxidants, glutathione peroxidase (GPx), showed significant response to tissue PCB. No significant correlation was found between tissue concentrations of chlorinated hydrocarbons and other enzymatic antioxidants (superoxide dismutase (SOD), catalase (CAT), glutathione reductase (GR) and NADPH DT-diaphorase (DT-d). Oxidative stress, measured as thiobarbituric acid reactive substances, was correlated with chlorinated pesticide concentrations in tissues. This study demonstrated a correlation between GST/GSH and chlorinated hydrocarbons. The apparent lack of correlation between trace organic pollutants and some of the enzymatic antioxidants may be due to the inhibitory effects caused by these chemicals. The above results suggest that more investigations are needed before these enzymes can be used as biomarkers. 相似文献
92.
We have shown previously that exposure of Atlantic croaker to a PCB mixture (Aroclor 1254) results in impaired reproductive neuroendocrine function. In addition, we have identified hypothalamic tryptophan hydroxylase (TPH), the rate-limiting enzyme in serotonin (5-hydroxytryptamine) synthesis, as a target of PCB neuroendocrine toxicity. In order to further elucidate the mechanisms of PCB neurotoxicity, the present study investigated whether PCB-induced decrease in hypothalamic TPH activity resulted from degradation of the enzyme protein. Fish were exposed to Aroclor 1254 in the diet (0.1 mg/100 g body weight (BW)/day) for 30 days. The PCB exposure elicited a significant decrease in hypothalamic TPH protein content, which could be at least partially responsible for the reduced TPH activity. To test whether a similar PCB exposure could cause oxidative damage in croaker hypothalamic tissues, we examined the formation of malondialdehyde (MDA) protein adducts as a marker of lipid peroxidation (LPO). The same dose of PCB increased the MDA-protein adduct formation in the hypothalamus. In a separate experiment, the role of vitamin E, an antioxidant, to prevent or decrease the effect of PCB on hypothalamic TPH activity and gonadal growth was examined. The vitamin E co-treatments (1 and 10 mg/100 g BW/day) with PCB significantly reduced the effects of PCB on TPH activity and gonadal growth. These results suggest possible involvement of oxidative processes in PCB neurotoxicity. 相似文献
93.
翡翠贻贝对多氯联苯吸收不同途径的比较研究 总被引：5，自引：0，他引：5
定量分析和比较翡翠贻贝Perna viridis对多氯联苯(PCBs)吸收的4种不同途径。结果表明，翡翠贻贝通过食物途径富集PCBs比从海水吸收的途径具更高效率；而通过底泥或悬浮颗粒积累PCBs的途径较为次要。翡翠贻贝对5—7个氯原子数的PCBs异构体富集率高，分别占PCBs总量的53．25％-77．41％。结果还表明，贻贝经沉积物途径和经滤食悬浮颗粒途径比经水途径和食物途径对含2—4个氯原子数和8—10个氯原子数的PCBs异构体富集率较高。 相似文献
94.
Margaret O. James Kevin M. Kleinow Youbo Zhang Ran Zheng Liquan Wang Laura R. Faux 《Marine environmental research》2004,58(2-5):343
Benzo(a)pyrene (BaP) and polychlorinated biphenyls (PCBs) often co-exist in contaminated environments. Polychlorobiphenylols (OH-PCBs), formed by CYP-dependent monooxygenation of PCBs, are potent inhibitors of the glucuronidation of hydroxylated BaP metabolites. We hypothesized that OH-PCBs could drive the biotransformation of (−)BaP-7,8-dihydrodiol (BaP-7, 8-D) away from detoxication and towards formation of the reactive metabolite. A mixture of five OH-PCBs with 4–6 Cl atoms was infused into isolated, perfused, biliary intact livers (n=3 fish) removed from 3-methylcholanthrene-induced channel catfish. Controls (n=3) were infused with vehicle. Subsequently, [3H]-BaP-7, 8-D was infused into each liver and bile was collected for 1 h. The livers were taken for analysis of metabolites and DNA adducts. Induction status was confirmed by EROD assay. Bile was analyzed for metabolites. It was found that preinfusion of the mixture of OH-PCBs reduced the extent of glucuronidation of BaP-7, 8-D and increased the formation of DNA adducts 5-fold over controls. GSH conjugates, tetrols and triols were increased in the OH-PCB-infused fish, providing further support for our hypothesis that if the glucuronidation were inhibited, CYP-dependent activation would increase. These studies suggest a mechanism for synergy of toxicity of PAH and PCBs. 相似文献
95.
Investigation of mechanisms of formation of biphenyls and benzonaphthothiophenes by simulation experiment 总被引：1，自引：0，他引：1
The formation mechanisms of biphenyl series and benzonaphthothiophene series are investigated by means of simulation experiment. Biphenyl series are likely formed in two ways: one is the aromatization of the chain compounds containing conjugated C== C double bonds or the compounds with such a kind of sidechains, and the other is the reaction of sulfur with ordinary chain compounds, in which sulphur acts on ordinary sidechain compounds by seizing some hydrogens and forming (H2S and) the intermediates with conjugated C== C double bonds first, and then the intermediates are aromatized. One of the basic precursors of benzonaphthothiophenes is likely the phenylnaphthalenes which may originate from the chain compounds containing conjugated C== C double bonds, the compounds with such sidechains and saturate or unsaturate chain compounds. Thermal stability of biphenyls is high, but they can become dibenzothiophenes and polycyclic aromatic hydrocarbons or dibenzofurans and polycyclic aromatic hydrocarbons respectively in the presence of sulphur or oxygen. The ratio of biphenyl and m-biphenyl to biphenyls may be employed to indicate the depositional environment in the mild to medium maturation, of which the higher value indicates a fresh water depositional environment and the lower indicates a saline depositional environment. The relative high content of benzonaphthothiophenes in the crude oil indicates that the crude oil has undergone an intense sulfurization in the source rock or reservoir. 相似文献
96.
PCBs in fish from the southern Baltic Sea: levels, bioaccumulation features, and temporal trends during the period from 1997 to 2006 总被引：1，自引：0，他引：1
Levels of seven marker polychlorinated biphenyls (PCBs) have been determined in five species of Baltic fish collected during 1997-2006. Downward time trends in the concentrations of heavier congeners of PCBs in different Baltic fish, with the exception of cod, have been observed between 1997 and 2001. In case of sprat and herring samples, the statistical significance of the time trends of the PCBs: 101, 118, 153, 138 and 180 concentrations has been proved. Species-specific bioaccumulation of PCBs has been indicated, and the lowest and highest levels of PCBs (expressed on the basis of lipid weight) have been observed in sprat and salmon samples, respectively. PCB profiles have been found to be similar in all the fish species tested. Sampling location has not been a crucial factor for the observed levels of various PCBs. In some fish species, PCB concentrations are negatively correlated with the fat content but have no relation with the fish length. 相似文献
97.
1 INTRODUCTION While wastewater discharge regulations have significantly reduced water column pollution, historical and accidental releases of organic pollutants and heavy metals continue to pose an ecological threat as these contaminants have become 搃n-place?sediment pollutants. It had been previously assumed that natural attenuation processes, such as burial or biodegradation, would decrease the contamination levels in surface sediments and, thus, diminish the environmental impact of t… 相似文献
98.
多氯联苯(PCBs)是一种具有亲脂性、低水溶性、高稳定性和高生物富集性等特性的持久性有机污染物(POPs),而沉积物作为疏水性有机污染物(HOCs)的重要地质宿体,PCBs在POPs中发生的环境过程是研究的热点。本文综述国内外近几年来沉积物中PCBs分析测定以及迁移转化的研究动态,并对今后PCBs污染的生物修复研究提出了自己的见解。 相似文献
99.
Polychlorinated biphenyls (PCBs) as Σ21 congeners, were investigated in atmospheric bulk deposition over one year, along a northern transect of France, including 5 sites from the Atlantic coast to the east of Paris. Evidence was obtained for an easterly rise of the PCB concentrations, from 3 to 76 ng L−1. The PCB patterns were depleted in low chlorinated congeners in rural areas whereas at urban sites, the profiles were typical of local sources. The seasonal variations of concentrations were mainly controlled by the temperature. Next, at Paris, PCB distribution between the gaseous and the particulate phases was studied, considering seasonal parameters and different fate processes. Their distribution showed a prevalence of congeners in the gaseous phase (0.15–1.17 ng m−3) which occurrence decreased from 93 to 68% with the rise of congener chlorination level. In the particulate phase, they ranged from 0.01 to 0.27 ng m−3, only. Rainwater concentrations ranged from 3.1 to 13.1 ng L−1. A total rain water/air washout ratio was determined and showed a negative correlation with those reported in the literature. That might be attributed to the importance of particle scavenging. The annual bulk deposition ranged from 8 to 29 μg m−2. A decreasing trend of PCB atmospheric levels over the last fifteen years was confirmed in the studied area. 相似文献
100.
《地学前缘(英文版)》2022,13(3):101376
In view of the accumulation of nanoplastics (NPs) in the food chain of environment and animals, and the good adsorption properties of nano-plastics to toxic substances, it is necessary to explore the influence of NPs in living organisms. In this study, single and joint toxicological effects of polystyrene nanoplastics (PS-NPs, size 80 nm) and polychlorinated biphenyls (PCBs), were explored in freshwater aquatic animal model zebrafish (Danio rerio). Our study found that exposure to single PS-NPs induced mild acute toxicity, albeit the combined exposure of PS-NPs and polychlorinated biphenyls aggravated the toxicity of PCBs in a dose-dependent manner. Results from gene expression profiling showed that NPs exposure could activate detoxification process, resulting in a slight up-regulation of antioxidant genes (sod1, gstp1), bone development genes (bmp2, bmp4) and cardiac gene (tbx20); while PCBs suppressed the detoxification through down-regulation of these genes, and the addition of NPs will exacerbate the impact of PCBs on gene suppression. Importantly, the results of in vivo purification experiments found that NPs showed prolonged retention in liver, intestine and gills of zebrafish and they might have crossed biological barrier and accumulate in lipid-rich tissues and excretion does not appear as the significant pathway for their elimination. In conclusion, the toxic effects of polychlorinated biphenyls on chorionic protected embryos were not significant as zebrafish chorion plays an important role in resisting the invasion of pollutants; PCBs can seriously damage the bone and heart development of zebrafish, while the presence of NPs significantly enhanced the toxicity of PCBs in zebrafish, which is an alarming concern for growing NPs levels and ecological safety in aquatic environment. 相似文献