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[en] The principal sources of the pollution of the environment by polychlorobiphenyls are indicated and their ecological danger is estimated; the output in the manufacture and applications of polychlorobiphenyls are quoted. The known methods for the neutralisation of polychlorobiphenyls are examined. The methods considered are analysed and their practical significance for industry is estimated. The bibliography includes 277 references.
[en] Historically, Mixed Liquid Waste (MLW) drums from Canadian facilities were shipped to a licensed US facility for destruction via incineration. In order to address the various challenges and complexities associated with this approach, Kinectrics developed a flexible process for disposal of both Poly Chlorinated Biphenyls (PCB) and non-PCB contaminated MLW within Canada. The objective of this paper is to present project case studies that provide an overview of the various approaches employed since 2010 by Kinectrics for management of MLW within Canada. Various innovative approaches to processing a variety of MLW, key results, recent developments, successes, challenges and lessons learned are discussed. (authors)
[en] Background: Many previous studies have dealt with the effect of polychlorinated biphenyls (PCBs) on the thyroid gland, but their findings are inconsistent. One problem of these studies has been their use of cross-sectional designs. Objectives: The aim of the current study is to investigate longitudinal effects of PCBs on the thyroid gland, focusing on: morphological changes in thyroid tissue (i.e. thyroid volume), changes in thyroid hormones and in thyroid antibodies. Methods: A total of 122 individuals (Mage=44.7) were examined over a period of four years (t1 until t4). Medical history was collected via interviews, an ultrasound examination was performed and blood samples were taken to determine plasma PCB levels, thyroid stimulating hormone (TSH), free triiodthyronine (fT3), free thyroxine (fT4), thyroid peroxidase antibodies (TPOab), thyreoglobulin antibodies (TGab) and thyroid-stimulating hormone receptor antibodies (TSHRab). Rank correlation coefficients and mixed effect models were performed controlling for age and total lipids. Results: There were negative correlations between higher chlorinated biphenyls and fT3, cross-sectionally as well as longitudinally. We also found an interaction effect of higher-chlorinated PCBs over time for fT4 as well as TSHRab. In case of high exposure, a decrease in fT4 and an increase in TSHRab level were found over time. In regards to the other variables, our findings yielded no clear results in the examined time period. Conclusion: This is the first study to shows a PCB-related effect on fT3, fT4 and TSHRab over a four year period. The data also suggest that morphological and antibody findings remain inconsistent and do not allow for unambiguous interpretation. - Highlights: • This is a longitudinal study which includes data from four cross sections. • Higher-chlorinated biphenyls are negatively correlated with fT3. • There are interactions of time and higher-chlorinated biphenyls to TSHRab and fT4. • There is an interaction of time and dioxin-like polychlorinated biphenyls to fT4. • No consistent effects were found for thyroid volume, TSH, TPOab and TGab.
[en] PCBs and p,p'-DDE constituted 90% of contaminants found. - The levels of polychlorinated camphenes (toxaphenes) were investigated in liver samples from 18 glaucous gulls (Larus hyperboreus) from Bjoernoeya (74 deg. N, 19 deg. E) and four individuals from Longyearbyen (78 deg. N, 15 deg. E). Additionally brominated flame retardants (BFRs), PCBs and chlorinated pesticides were investigated in liver and intestinal contents of 15 of the glaucous gulls from Bjoernoeya. Of the analysed BFRs only 2,2',4,4'-tetra- and 2,2',4,4',5-pentabrominated diphenylethers (PBDE 47 and 99) could be detected. The concentrations ranged between 2 and 25 ng/g ww. In addition, high resolution measurements with GC/HRMS revealed the existence of several, not quantified, PBDEs and polybrominated biphenyls (PBBs) congeners in the samples. B9-1679 and B8-1413 were the dominating toxaphenes with median concentrations of 8 and 15 ng/g ww. Concentrations of toxaphenes and PBDEs were up to 100-times lower than the concentrations of PCB and some of the pesticides. PCB and p,p'-DDE constituted 90% of the contaminants found
[en] N-limited stationary cultures of the white rot fungi Phanerochaete chrysosporium, Trametes versicolor, and Coriolopsis polysona mineralized 1.393 ± 0.353 (0.301 ± 0.023) and 0.398 ± 0.061 (0.112 ± 0.010), and 0.015 ± 0.004 (0.002 ± 0.0008) % of the originally supplied 30.14 nmol (513.7 nmol) of 3,3′,4,4′-tetrachloro[U-14C]biphenyl (PCB 77) during 4 weeks. The extent of PCB 77 degradation was followed by 14C-radioactivity partitioning into aqueous, organic soluble, biomass associated, aqueous (intracellular) and organic soluble (intracellular) fractions. After four weeks incubation the pattern of distribution of radioactivity was similar in P. chrysosporium and C. polysona at higher dose but not at the lower dose of PCB 77. T. versicolor differed in the distribution pattern of radiolabel
[en] Highlights: • PCB concentrations were studied in silicone-based adhesives and chlorophenylsilanes. • Congener patterns (CP) were studied in adhesives and chlorophenylsilanes. • High concentrations of PCBs were detected in dichlorodiphenylsilane. • In commercial adhesives, PCBs with similar CP to dichlorodiphenylsilane were found. • CP were affected by the chlorobenzene used for synthesizing chlorophenylsilanes. - Abstract: This paper discusses the concentrations and congener patterns of PCBs unintentionally present in chlorophenylsilanes. Chlorophenylsilanes are used in the production of silicone-based adhesives and phenyl silicones. The concentration of PCBs in adhesives was found to range from not-detectable concentrations to 40 mg/kg. The concentrations of PCBs in trichlorophenylsilane, dichlorodiphenylsilane, chlorotriphenylsilane, and diphenylsilanediol were 0.00072–2.7, 6.5–1,500, 0.019–1.1, and 0.12–120 mg/kg, respectively. Dichlorodiphenylsilane and diphenylsilanediol, in particular, had high PCB concentrations. The PCB concentration of some specimens exceeded the 50 mg/kg limit set by the transportation regulations of the Stockholm Convention. In the adhesives and chlorophenylsilanes, mono- and di-chlorinated biphenyls were detected in high proportions. The congeners detected in dichlorinated biphenyls had a structure in which one chlorine atom was substituted at each of the two aryls of the biphenyl backbone. This indicated that the chlorobenzene used for synthesizing chlorophenylsilanes undergoes dimerization. The congener and homologue patterns of the adhesives containing PCBs were similar to dichlorodiphenylsilane and diphenylsilanediol. It was concluded that the production of the adhesives is based on these substances. In addition, these results indicate that silicone-based products may become a source of PCBs in the environment, leading to irregular PCB values in environmental analysis
[en] Graphical abstract: - Highlights: • Quantum chemical calculations were carried out for PCBs congeners. • Calculated descriptors were used to explain the PCBs reactivity in SN and SE substitutions. • Obtained data were used to estimate the PCBs reactivity in the SN reactions. • Calculated descriptors were insufficient to explain the PCBs reactivity in the SE reactions. • New neutralization methods of the large-capacity PCBs were discussed. - Abstract: To explain the chemical reactivity of polychlorinated biphenyls in nucleophilic (SN) and electrophilic (SE) substitutions, quantum chemical calculations were carried out at the B3LYP/6-31G(d) level of the Density Functional Theory in gas phase. Carbon atomic charges in biphenyl structure were calculated by the Atoms-in-Molecules method. Chemical hardness and global electrophilicity index parameters were determined for congeners. A comparison of calculated descriptors and experimental data for congener reactivity in the SN and SE reactions was made. It is shown that interactions in the SN mechanism are reactions of the hard acid–hard base type, these are the most effective in case of highly chlorinated substrates. To explain the congener reactivity in the SE reactions, correct descriptors were not established. The obtained results can be used to carry out chemical transformations of the polychlorinated biphenyls in order to prepare them for microbiological destruction or preservation
[en] The BIODEP model in terms of atmosphere-lake interactions was developed. The model was applied to an oligotrophic, dimictic high altitude lake (Lake Redo, Pyrenees) for a range of polychlorinated biphenyl (PCB) congeners. High altitude lakes, which receive their contaminant inputs uniquely from the atmosphere through long-range atmospheric transport, provide ideal controlled environments for the study of the interactions between atmospheric depositional and water column biogeochemical processes. The BIODEP model was able to predict dissolved water concentrations and PCB accumulation in the lake sediment within a factor of 2. This shows that the BIODEP model captures the essential processes driving the sink of POPs in high altitude lakes and that POP occurrence in the lake is driven by direct atmospheric inputs with limited influence from the watershed. An important seasonal variability in water column concentrations is predicted which should have important implications in sampling strategies. Furthermore, it is shown that diffusive air-water exchange dominated the PCB dynamics in the lake, especially for the less chlorinated biphenyls. - A dynamic flux model was able to accurately predict PCB levels
[en] Pristine mountains are ideal settings to study transport and behavior of persistent organic pollutants (POPs) along gradients of climate and land cover. The present work investigated the concentrations and patterns of 28 organochlorine pesticides (OCPs), 25 polychlorinated biphenyl (PCBs), 13 polybrominated diphenyl ethers (PBDEs), and 3 hexabromocyclododecane (HBCDs) isomers in the air of the Shergyla Mountain, southeastern Tibetan Plateau. Endosulfan I, hexachlorobenzene, pentachlorobenzene, hexachlorocyclohexanes and dichlorodibenzotrichloroethane and its degradation products (DDTs) were the predominant compounds while PBDEs and HBCDs showed the lowest background concentrations. Most of the target POPs had significantly higher concentrations in summer than those in winter. Increasing trends of the concentrations of DDTs and endosulfan were found with increasing altitude on the western slope in the Shergyla Mountain. Potential forest filter effect was observed based on the lower air concentrations of the target POPs in the forest than the ones out of the forest. - Highlights: • Concentrations of DDT and endosulfan increased with elevation in Shergyla Mountain. • Potential forest filter effect for some POPs was observed in summer in the Plateau. • Seasonal variations of POPs levels existed in atmosphere of the Plateau. • Different behavior of POPs was observed on the two slopes of the Shergyla Mountain. - Different behaviors of POPs were observed on the two slopes of the Shergyla Mountain, and potential forest filter effects for some POPs were observed in the summer
[en] Bacterial dioxygenases are useful in breakdown of PCB products associated with plants. - Capacity of enzymes of the biphenyl/chlorobiphenyl pathway, especially biphenyl dioxygenase (BPDO) of two polychlorinated biphenyls (PCB) degrading bacteria, Burkholderia sp. LB400 and Comamonas testosteroni B-356, to metabolize ortho-substituted hydroxybiphenyls was tested.,These compounds found among plant products of PCB metabolism, are carrying chlorine atoms on the hydroxyl-substituted ring. The abilities of His-tagged purified LB400 and B-356 BPDOs to catalyze the oxygenation of 2-hydroxy-3-chlorobiphenyl, 2-hydroxy-5-chlorobiphenyl and 2-hydroxy-3,5-dichlorobiphenyl were compared. Both enzyme preparations catalyzed the hydroxylation of the three chloro-hydroxybiphenyls on the non-substituted ring. Neither LB400 BPDO nor B-356 BPDO oxygenated the substituted ring of the ortho-hydroxylated biphenyl. The fact that metabolites generated by both enzymes were identical for all three hydroxychlorobiphenyls tested; exclude any other mode of attack of these compounds by LB400 BPDOs than the ortho-meta oxygenation