Journal articles: 'PCBs'

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Zhang, Hang, Zuo Lun Wang, Jie Ding, and Wen Sheng Linghu. "A Study on Pyrolysis of Waste Printed Circuit Boards in a Batch Reactor." Advanced Materials Research 1033-1034 (October 2014): 359–63. http://dx.doi.org/10.4028/www.scientific.net/amr.1033-1034.359.

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In this work the pyrolysis of waste printed circuit boards (PCBs) were investigated through TG technology and a quartz tube batch reactor, respectively. The TG analysis results showed that the total mass loss from 30-800oC for PCB1 and PCB2 were 35.7% and 41.1%, respectively. With the increase of pyrolysis temperature in a batch reactor, gas yield of PCB2 increased, but increasing rate gradually decreased. The gas yield of PCB2 for pyrolysis time of 1min, 5min and 10min at 600 °C were 30.5%, 31.1% and 31.7%, respectively. It is suggested that the better pyrolysis temperature was at the range of 500-600 °C and the optimal pyrolysis time was 1min. The higher gas yield of PCB2 was obtained at air atmosphere than that at nitrogen atmosphere.

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Kraft, Martin, Knut Rauchfuss, Hermann Fromme, Lothar Grün, Silvia Sievering, Barbara Köllner, and Yvonni Chovolou. "Inhalation Exposure to PCB from Contaminated Indoor Air—How Much Is Absorbed into the Blood?" Pollutants 1, no. 3 (September 1, 2021): 181–93. http://dx.doi.org/10.3390/pollutants1030015.

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Polychlorinated biphenyls (PCBs) were used in many construction products until their banning in the 1970s and 1980s. Nonetheless, exposure to PCBs from contaminated indoor air is still an important public health issue. The aim of our study was to estimate the contribution of PCB congeners in indoor air to the levels of PCBs in human blood. We analyzed all 209 PCB congeners in the blood of 35 individuals exposed to PCBs from contaminated indoor air. For each individual, we measured the six marker indicators PCB28, PCB52, PCB101, PCB138, PCB153 and PCB180 in indoor air at the workplace. Statistically significant correlations between PCB-contaminated indoor air and the existence of the sum of mono-, di-, tri-, tetra- and pentachlorinated biphenyls (∑PCB1–127) in the blood of the exposed individuals were found. We quantified the proportions of PCBs that are absorbed into the blood via inhalation of contaminated indoor air. Inhalation of PCBs from contaminated indoor air, especially in children, adolescents and younger adults, may lead to PCB blood burdens that are higher than general PCB background levels or in approximately the same range.

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Hortense, Hampoh Adé, Ehouman Ano Guy Serge, Dalogo Kakou Alain Paterne, Brou Kouakou, and Traore Karim Sory. "Reduction of Polychlorinated Biphenyls (PCB) In Fresh Fish from the Grand Lahou Lagoon for Healthy Consumption." Scholars Academic Journal of Biosciences 11, no. 1 (January 23, 2023): 23–26. http://dx.doi.org/10.36347/sajb.2023.v11i01.004.

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The Grand Lahou lagoon system receives numerous spills from inland waters. This results in various forms of chemical pollution. Two species of fish most consumed by the Grand Lahou population are contaminated with high levels of Polychlorinated Biphenyls (PCBs). The objective of this study is to reduce the levels of PCBs in both fish species in order to provide consumers with healthy fish. The fish species most contaminated with PCBs, namely a type of catfish called ‘‘machoiron’’ (Chrysichthys sp.) and the mullet (Mugil sp.) were collected according to their weight (category 1:101-200g and category 2: 201-300g). Smoking has been proposed to reduce PCB levels. Thus two smoking techniques were used: smoking the fish traditionally using firewood as fuel and smoking on barbecue with charcoal. The level of PCB contamination in fish was determined by the gas chromatograph coupled with an electron capture detector (GC-ECD). The results obtained show that the smoking techniques used reduce the PCBi content. Wood smoking eliminates 98% of PCBs from fish compared to 88% for charcoal smoking.

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Burd, Brenda J., Christopher J. Lowe, and Carmen Morales-Caselles. "Uptake of PCBs into sediment dwellers and trophic transfer in relation to sediment conditions in the Salish Sea." FACETS 7 (January 1, 2022): 936–65. http://dx.doi.org/10.1139/facets-2021-0032.

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We examined uptake of polychlorinated biphenyls (PCBs) into various marine sediment feeders relative to physical and geochemical factors and transfer to higher trophic levels. PCBs exceeding Canadian Council Ministers of the Environment Guidelines by 6–55× were found in industrialized harbours and some near-outfall sediments, indicating ongoing land input. Sediment PCBs were correlated with organic flux and content. Tissue PCBs were >10× sediment PCBs in all samples and highest in Victoria Harbour infauna, suggesting considerable uptake from these extremely contaminated, organically enriched, chronically disturbed sediments. Sediment PCBs were the primary predictor of tissue lipid PCBs followed by %fines. This results in generally higher tissue PCBs in more depositional regions. The lipid/sediment PCBs (uptake rate) declined with increasing sediment PCBs, acid volatile sulfides and benthos biomass turnover. PCB homologue composition did not change with uptake from sediments or at higher trophic levels, suggesting minimal metabolization in tissues. Trophic bio-magnification occurs since lipid PCBs were 2–100× higher in seal blubber than sediment feeders. PCBs were compared with polybrominated diphenyl ethers (PBDEs) for the same samples. PCBs were highest in industrialized harbours, whereas PBDEs were elevated in harbours but highest near wastewater discharges. This reflects differences in usage history, sediment dynamics, and affinities. PCBs appear to be more bio-accumulative and persistent at higher trophic levels than PBDEs.

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Chun, Man-Young. "Depositional Characteristics of Atmospheric PCBs in Several Media Used Passive Air Samplers." Korean Journal of Environmental Health Sciences 39, no. 2 (April 30, 2013): 151–58. http://dx.doi.org/10.5668/jehs.2013.39.2.151.

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Li, Zhi Yong, Yu Ling Zhang, and Shi Qing Ni. "PCBs in Air from an Industrial Zone in a Coastal City-Tianjin, China." Applied Mechanics and Materials 587-589 (July 2014): 546–49. http://dx.doi.org/10.4028/www.scientific.net/amm.587-589.546.

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The 23 air samples were collected from Tianjin Dongli industrial zone from July 2010 to May 2011 for the analysis of 84 PCB congeners to investigate the gas/particle partitioning. The total PCBs concentration ranged from 71.08 to 567.36 pg m-3 with the mean value as 307.78±137.45 pg m-3 and the seasonal trends were summer >winter >spring >autumn. Gas PCBs accounted for 77.47% of the total PCBs. The fraction of each gas PCB homolog increased with the decreasing chlorine atoms. The contribution of gas PCBs to total PCBs showed a strong seasonal variation with summer (92.44%)> autumn (85.16%) > spring (80.61%) > winter (42.70%). Tri-, tetra-, penta-PCBs and di-PCBs were the predominantly homologs in atmosphere from industrial zone in Tianjin. The natural logarithm of partial pressure of PCBs were well correlated with the inverse absolute environmental temperature (R=0.77). The steep slope of-3764 obtained from Clausius–Clapeyron plot indicated the influence of local PCBs sources.

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Sasaki, Nozomi, Laura Jones, Gayle Morse, and David Carpenter. "Mixture Effects of Polychlorinated Biphenyls (PCBs) and Three Organochlorine Pesticides on Cognitive Function in Mohawk Adults at Akwesasne." International Journal of Environmental Research and Public Health 20, no. 2 (January 9, 2023): 1148. http://dx.doi.org/10.3390/ijerph20021148.

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The Mohawks at Akwesasne have been highly exposed to polychlorinated biphenyls (PCBs), via releases from three aluminum foundries located near the reserve. They are also exposed to organochlorine pesticides, namely hexachlorobenzene (HCB), dichlorodiphenyldichloroethylene (DDE), and mirex. Previous studies have demonstrated reduced cognition in relation to total PCBs, but the effects of the mixtures of different PCB congener groups, HCB, DDE, and mirex on cognitive function have not been studied. Therefore, cognitive performance for executive function, scored via the digit symbol substitution test (DSST), in Mohawk adults aged 17–79 years (n = 301), was assessed in relation to serum concentrations of low-chlorinated PCBs, high-chlorinated PCBs, total PCBs, HCB, DDE, and mirex. We used mixture models employing the quantile-based g-computation method. The mixture effects of low-chlorinated PCBs, high-chlorinated PCBs, HCB, DDE, and mirex were significantly associated with 4.01 DSST scores decrements in the oldest age group, 47–79 years old. There were important contributions to mixture effects from low-chlorinated PCBs, high-chlorinated PCBs, and total PCBs, with smaller contributions of HCB and DDE. Our findings indicate that exposures to both low- and high-chlorinated PCBs increase the risk of cognitive decline in older adults, while DDE and HCB have less effect.

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Raloff, Janet. "New PCBs?" Science News 164, no. 17 (October 25, 2003): 266. http://dx.doi.org/10.2307/4018879.

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Raloff, Janet. "Detoxifying PCBs." Science News 132, no. 10 (September 5, 1987): 154. http://dx.doi.org/10.2307/3971945.

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10

Alford-Stevens, Ann L. "Analyzing PCBs." Environmental Science & Technology 20, no. 12 (December 1986): 1194–99. http://dx.doi.org/10.1021/es00154a001.

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Zhang, Xi, Feng Li, Tingting Liu, Cheng Peng, Dechao Duan, Chen Xu, Shenhai Zhu, and Jiyan Shi. "The Influence of Polychlorinated Biphenyls Contamination on Soil Protein Expression." ISRN Soil Science 2013 (December 4, 2013): 1–6. http://dx.doi.org/10.1155/2013/126391.

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Polychlorinated biphenyls (PCBs) are typical representative of chlorinated organic pollutants. Given the toxicity of PCBs, there is an urgent need to select an appropriate indicator to monitor their biological effects on soil ecosystems. For this purpose, we investigated the impacts of PCBs on soil protein and the potential of using protein as a biological indicator to assess soil contamination due to PCBs. This study demonstrated that soil protein concentration and expression were negatively affected by PCBs. In addition, significantly (P<0.01) negative correlation was observed between protein concentration and PCBs. Subsequently, protein size distribution separated by SDS-PAGE revealed that with the increase in PCBs concentration there are less large molecular weight proteins and more low molecular weight proteins (<40 kD). Consequently, soil protein level has the potential to be an indicator of soil contamination, and these low molecular weight proteins have significant meaning for getting insight into the ecological effects of PCBs on the soil environment.

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Bai, Si Hong, Zhi Fu Qi, Jie Liu, Tong Chen, Sheng Yong Lu, and Xiao Dong Li. "Effect of Carrier Gas Flow Rate in Thermal Desorption Process of PCBs Contaminated Soil." Advanced Materials Research 878 (January 2014): 731–38. http://dx.doi.org/10.4028/www.scientific.net/amr.878.731.

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A real PCBs contaminated soil was heated at 500°C using pure nitrogen as carrier gas under different flow rate to investigate the influence of carrier gas flow rate on the thermal desorption process. After 1 hour thermal treatment, the residual PCBs in soil decreased and the removal efficiency (RE) of PCBs is up to 95.1%. The distributions of PCBs in soil under different flow rate were identical. The World Health Organization toxic equivalency quantity (WHO TEQ) of PCBs in soil got its lowest value at 400Nml/min. Tetra-and higher chlorinated PCBs desorbed to carrier gas increased with increased flow rate, while the total amount of PCBs, Tri-and lower chlorinated PCBs first increased then decreased. The distributions of PCBs in carrier gas became more closely to the raw soil with increased flow rate. The TEQ of PCBs in carrier gas increased with increased flow rate. Increased flow rate enhanced the mass transfer of PCBs in the soil but shortened the preheating time of carrier gas and the retention time of carries gas, weakening the mass transfer and degradation process in gas phase. The RE of WHO TEQ of PCDDs in treated soil decreased from 86.7% to 83.2% with increased flow rate while the RE of WHO TEQ of PCDFs decreased from 85.4% to 70.0%. After thermal treatment process, the total amount of PCDD/Fs TEQ in soil and carrier gas increase from 43.8% to 18.6% times of that in raw soil. Considering removal efficiency of PCBs and PCDD/Fs and generation of PCDD/Fs in soil and gas phase, an optimized flow rate should be set at about 400Nml/min.

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Tivol, William F., Ann C. Casey, Xuemei Liu, and Brian Bush. "Binding of Polychlorinated Biphenyls to Sediment." Microscopy and Microanalysis 4, S2 (July 1998): 498–99. http://dx.doi.org/10.1017/s1431927600022613.

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Transport, cleanup, and bioremediation properties of polychlorinated biphenyls (PCBs) bound to sediments depend on the specific components to which the PCBs are bound. Analysis of the sediment from Contaminant Cove on the St. Lawrence River by gas chromatography with an electron capture detector shows that the sediment contains 600 ppm PCBs. Previous work showed that there were both weak and strong binding of PCBs to sediment components, but gave no indication of which components were responsible for the binding.2 The average content of PCBs is below the limit of detectability by energy-dispersive x-ray microanalysis (EDX) for CI, but constituents which bind large quantities of PCBs could be detected. Sediment which is not contaminated with PCBs contains no detectable chlorine.EDX analysis was performed on a JEOL JEM-4000FX, using a cryo-stage (operated at -160° C) and a Tracor TN5500 system.

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Peng, Wei, Zhen Dong Fang, Hua Qiao, Quan Long Hao, Kai Zhang, and Hai Bo Yu. "A Review on Remediation Technologies of PCBs from the Contaminated Soils or Sediments." Advanced Materials Research 955-959 (June 2014): 2238–42. http://dx.doi.org/10.4028/www.scientific.net/amr.955-959.2238.

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Polychlorinated biphenyls, which are toxic, carcinogenic and mutagenic, are ubiquitous and persistent in environment. For PCBs are hydrophobic and lipophilic, soils or sediments are their final destinations in environment. Consequently, PCBs-contaminated soils or sediments are increasingly attracting more and more attention. In this paper, basic properties of PCBs and the situation of PCBs-contaminated soils or sediments were described. Remediation technologies of PCBs-contaminated soils or sediments inside and outside China were reviewed. This paper also presented the prospect of technology development.

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Li, Ye, Ye Huang, Yunshan Zhang, Wei Du, Shanshan Zhang, Tianhao He, Yan Li, et al. "Temporal and spatial variations in atmospheric unintentional PCB emissions in Chinese mainland from 1960 to 2019." Atmospheric Chemistry and Physics 23, no. 2 (January 23, 2023): 1091–101. http://dx.doi.org/10.5194/acp-23-1091-2023.

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Abstract. Polychlorinated biphenyls (PCBs) are nowadays mainly unintentionally produced, since their use and manufacture has been banned. PCBs, especially those dioxin-like compounds, have been proven harmful to ecosystems and human health. Detailed information about the spatiotemporally distribution of unintentionally produced PCBs (UP-PCBs) is crucial for understanding the environmental fate and associated health risks. However, research estimating UP-PCBs emission in China is limited. In this study, a source-specific and year-varying emission factor (EF) dataset was used to compile provincial emissions of 12 dioxin-like UP-PCBs congeners for 66 sources in the Chinese mainland from 1960 to 2019. In addition to that, emissions for 2019 were allocated into 0.1∘×0.1∘ grids. The results indicated that historical national UP-PCBs emission represented an increasing trend until around 1995 and then showed an overall decreasing trend from 1995 to 2019. Cement production was the largest UP-PCBs emission source in the Chinese mainland. Geographically, East and North China contributed the largest UP-PCBs emission across the Chinese mainland. High emission densities occurred mainly in the densely populated and well-developed regions such as Yangtze River Delta Urban Agglomeration and Pearl River Delta. Furthermore, highly positive correlations of emission densities with population and GDP densities were identified.

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Liu, You Shi, Man Ying Ma, and Zhou Shi. "Application of Rhamnolipid Biosurfactant for Removing Polychlorinated Biphenyls from Contaminated Soil." Advanced Materials Research 233-235 (May 2011): 608–13. http://dx.doi.org/10.4028/www.scientific.net/amr.233-235.608.

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Rhamnolipid (RL) was used to study the removing of polychlorinated biphenyls (PCBs) from contaminated soils. The results showed that RL obviously enhanced desorption of PCBs from soils and RL was more effective than POE(6).Pseudomonas strainLB400 was able to grow rapidly in the medium with RL, POE(6) or biphenyl as carbon source. PCBs biodegraded in growing cells were greater than that in resting cells. In growing cells with RL as carbon source, when the incubating time reached 72 h, PCBs Biodegraded was 98.7% and increased by 0.5% compared with that with biphenyl as carbon source. PCBs degraded were the lowest in all kinds of cell systems with POE(6) as carbon source. In the growing cell system,P.LB400 was able to fully utilize RL, so the cell density and PCBs Biodegraded rapidly increased with the increase of the concentration of RL. However, in the resting cell system, RL had negative impact on biodegradation of PCBs.

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Gaum, Petra, Monika Gube, André Esser, Thomas Schettgen, Natalia Quinete, Jens Bertram, Franziska Putschögl, Thomas Kraus, and Jessica Lang. "Depressive Symptoms After PCB Exposure: Hypotheses for Underlying Pathomechanisms via the Thyroid and Dopamine System." International Journal of Environmental Research and Public Health 16, no. 6 (March 16, 2019): 950. http://dx.doi.org/10.3390/ijerph16060950.

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Polychlorinated biphenyls’ (PCB) exposure has been reported to be associated with depressive symptoms, which is correlated to lower dopamine- (DA) and thyroxine-concentrations (T4). T4 is necessary for DA-synthesis and it binds to transthyretin (TTR) being transported into the brain. PCBs can displace T4 by binding to TTR itself, being transported into the brain and disturbing DA-synthesis, where depressive symptoms might occur. Consequently, the free T4-concentration (fT4) increases when PCBs bind to TTR. The interaction of PCBs with fT4 and its associations with the main DA metabolite, homovanillic acid (HVA), and depressive symptoms were investigated. In total, 116 participants (91.6% men) were investigated, who took part in three annual examinations (t1–t3) of the HELPcB health surveillance program. Blood was collected for measuring PCBs, hydroxy PCBs (OH-PCBs), and fT4 and urine for HVA. Depressive Symptoms were assessed with a standardized questionnaire. Interactions were tested cross-sectionally with multiple hierarchical regressions and longitudinally with mixed effect models. Related to HVA, an interaction was cross-sectionally found for lower-chlorinated PCBs (LPCBs) and dioxin-like PCBs (dlPCBs); longitudinally only for LPCBs. Related to depressive symptoms, the interaction was found for LPCBs, dlPCBs, and OH-PCBs; longitudinally again only for LPCBs. The results give first hints that a physiological process involving the thyroid and DA system is responsible for depressive symptoms after PCB exposure.

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Klocke, Carolyn, and Pamela J. Lein. "Evidence Implicating Non-Dioxin-Like Congeners as the Key Mediators of Polychlorinated Biphenyl (PCB) Developmental Neurotoxicity." International Journal of Molecular Sciences 21, no. 3 (February 4, 2020): 1013. http://dx.doi.org/10.3390/ijms21031013.

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Despite being banned from production for decades, polychlorinated biphenyls (PCBs) continue to pose a significant risk to human health. This is due to not only the continued release of legacy PCBs from PCB-containing equipment and materials manufactured prior to the ban on PCB production, but also the inadvertent production of PCBs as byproducts of contemporary pigment and dye production. Evidence from human and animal studies clearly identifies developmental neurotoxicity as a primary endpoint of concern associated with PCB exposures. However, the relative role(s) of specific PCB congeners in mediating the adverse effects of PCBs on the developing nervous system, and the mechanism(s) by which PCBs disrupt typical neurodevelopment remain outstanding questions. New questions are also emerging regarding the potential developmental neurotoxicity of lower chlorinated PCBs that were not present in the legacy commercial PCB mixtures, but constitute a significant proportion of contemporary human PCB exposures. Here, we review behavioral and mechanistic data obtained from experimental models as well as recent epidemiological studies that suggest the non-dioxin-like (NDL) PCBs are primarily responsible for the developmental neurotoxicity associated with PCBs. We also discuss emerging data demonstrating the potential for non-legacy, lower chlorinated PCBs to cause adverse neurodevelopmental outcomes. Molecular targets, the relevance of PCB interactions with these targets to neurodevelopmental disorders, and critical data gaps are addressed as well.

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Han, Linrong, Chao Chang, Shiwei Yan, Chengkai Qu, Yulu Tian, Jipu Guo, and Jiahua Guo. "Distribution, Sources and Risk Assessment of Polychlorinated Biphenyls in Sediments from Beiluo River." Toxics 11, no. 2 (January 31, 2023): 139. http://dx.doi.org/10.3390/toxics11020139.

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The distribution and source of polychlorinated biphenyls (PCBs) pollution in the Beiluo River, the secondary tributary of the Yellow River, still remain unclear. With the purpose of determining the distribution, origins, and pollution levels of PCBs and their consequences on ecological risks, the concentrations of 27 PCBs at 17 locations in the sediments of the Beiluo River were examined in this study. The results showed that the mass concentrations of ∑PCBs in the sediment ranged from 0.12 to 1.25 ng∙g−1 (DW), with the highest point at sampling site B13 downstream of the river. Compared to most river sediments, both domestically and internationally, the concentration of PCBs in the sediment of the Beiluo River was at a low level, with 10-PCB and 6-PCB as the main components, indicating that the PCBs that are difficult to volatilise and degrade are more likely to remain in the sediment. The origins of PCBs in the sediments of the Beiluo River were examined by using positive matrix factorisation (PMF). The results revealed that the contamination of PCBs in the sediments of the Beiluo River mainly resulted from industrial emissions, technical PCB mixtures, and coal and wood combustion. The results of the ecological risk assessment indicated that PCBs in the sediments of the study area rarely contribute to adverse biological effects and the potential low risk to the environment.

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Chmil, V. D., O. V. Golokhova, D. Yu Vydrin, and V. I. Kruk. "Relevance of the problem of dioxins and polychlorinated biphenyls (PCBs) determination in baby food products." One Health and Nutrition Problems of Ukraine 52, no. 1 (June 24, 2020): 32–39. http://dx.doi.org/10.33273/2663-9726-2020-52-1-32-39.

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The Aim of the Article. Analysis of the current state of the problem of the dioxins and polychlorinated biphenyls (PCBs) determination in baby food products and the development of sample preparation methods for determining these xenobiotics in food products for infants and young children. Dioxins form a group of structurally and chemically related chlorinated tricyclic oxygen-containing aromatic compounds (congeners), which includes 75 polychlorinated dibenzo-para-dioxins (PCDDs) and 135 polychlorinated dibenzofurans (PCDFs). The most toxic congeners of dioxins, in which chlorine atoms along with other positions are necessarily in 2,3,7,8 positions of benzene rings. Their total number is 17:7 PCDD congeners and 10 PCDF congeners. A group of polychlorinated biphenyls (PCBs) – chlorinated bicyclic aromatic compounds, which consists of 209 different congeners, 12 of which have a spatial and electronic structure and exhibit toxicological properties similar to dioxins, therefore, they are called dioxin-like PCBs (DL-PCBs). In addition, when monitoring food products as a marker, a group of 6 PCBs was selected that did not exhibit dioxin-like toxicity and therefore did not belong to dioxin-like PCBs (NDL-PCBs). Thus, of the total number of 419 PCDDs, PCDFs and PCBs, only 35 are toxicologically significant, therefore, these compounds are subject to control in baby food products. To control the content of the amount of dioxins, the amount of dioxins and DL-PCBs and the amount of NDL-PCBs in foods for infants and children from one to three years in Ukraine, the maximum levels of these compounds on the basis of the order of the Ministry of Health of Ukraine No. 368 of 05/13/2013 were harmonized with the maximum allowable levels in foods for infants and young children in accordance with Commission Regulation (EU) No. 1259/2011. Methods for the analysis of dioxins and PCBs. Two instrumental analysis methods are used to determine dioxins and dioxin-like PCBs in foods for baby food: 1) a combination of high-resolution (capillary) gas chromatography with high-resolution mass spectrometry (GC/MS); 2) a combination of GCHR with tandem mass spectroscopy (GC/MS/MS). High-resolution (capillary) gas chromatography is used to determine non-dioxin-like (marker) PCBs. The stage of sample preparation, including the stages of extraction and purification, is key in determining dioxins and PCBs. Conclusions. The stage of sample preparation using automatic devices (liquid extraction under pressure, an automated extract purification system) and chromatographic columns was developed to further determine the mass concentration of dioxins and PCBs in baby food products. The developed procedures using devices for the automatic extraction and purification of the obtained extracts from baby food samples will make it possible in the future to determine PCDDs/PCDFs, ortho-unsubstituted, mono-ortho-substituted and marker PCBs in one sample. Key Words: dioxins, polychlorinated biphenyls, baby food.

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Galbán-Malagón, C. J., S. Del Vento, A. Cabrerizo, and J. Dachs. "Factors affecting the atmospheric occurrence and deposition of polychlorinated biphenyls in the Southern Ocean." Atmospheric Chemistry and Physics Discussions 13, no. 7 (July 12, 2013): 18779–808. http://dx.doi.org/10.5194/acpd-13-18779-2013.

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Abstract. Persistent organic pollutants, such as polychlorinated biphenyls, reach the Southern Ocean atmosphere through long-range atmospheric transport. In this study we report the largest data set available for the atmospheric occurrence of PCBs in the Southern Ocean surrounding the Antarctic Peninsula from samples obtained during three cruises in 2005, 2008 and 2009. The gas phase concentrations of total PCBs (σ25PCBs) ranged from 1 to 70 pg m-3, while the aerosol phase concentrations were significantly lower (0.04 to 0.4 pg m-3). The aerosol phase is enriched in the more hydrophobic congeners consistent with the model predictions of gas-particle partitioning. There is a net air to water diffusive flux of PCBs to the Southern Ocean, up to 50 times higher than the dry deposition flux of aerosol-bound PCBs. The air–water disequilibrium is higher for the more hydrophobic congeners consistent with the role of the biological pump removing PCBs from the water column by settling of PCBs bound to organic matter. The atmospheric half-lives of PCB 52 and 180 are of 3.8 and 1 days, respectively, as predicted from the measured atmospheric concentration and depositional fluxes. The volatilization of PCBs from Antarctic soils during the Austral summer drives higher gas phase concentrations in the atmosphere over Antarctica during the warmer periods. This temperature dependence is not observed for PCBs over the adjacent Southern Ocean, probably due to the importance of long-range atmospheric transport and atmospheric deposition modulating the atmospheric occurrence of PCBs.

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Galbán-Malagón, C. J., S. Del Vento, A. Cabrerizo, and J. Dachs. "Factors affecting the atmospheric occurrence and deposition of polychlorinated biphenyls in the Southern Ocean." Atmospheric Chemistry and Physics 13, no. 23 (December 12, 2013): 12029–41. http://dx.doi.org/10.5194/acp-13-12029-2013.

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Abstract. Persistent organic pollutants, such as polychlorinated biphenyls, reach the Southern Ocean atmosphere through long-range atmospheric transport. In this study we report the largest dataset available for the atmospheric occurrence of PCBs in the Southern Ocean surrounding the Antarctic Peninsula from samples obtained during three cruises in 2005, 2008 and 2009. The gas phase concentrations of total PCBs (Σ25PCBs) ranged from 1 to 70 pg m−3, while the aerosol phase concentrations were significantly lower (0.04 to 0.4 pg m−3). The aerosol phase is enriched in the more hydrophobic congeners consistent with the model predictions of gas-particle partitioning. There is a net air-to-water diffusive flux of PCBs to the Southern Ocean, up to 100 times higher than the dry deposition flux of aerosol-bound PCBs. The air-water disequilibrium is higher for the more hydrophobic congeners consistent with the role of the biological pump removing PCBs from the water column by settling of PCBs bound to organic matter. The atmospheric half-lives of PCB 52 and 180 are of 3.8 and 1 days, respectively, as calculated from the measured atmospheric concentration and depositional fluxes. The volatilization of PCBs from Antarctic soils during the austral summer drives higher gas phase concentrations in the atmosphere over Antarctica during the warmer periods. This temperature dependence is not observed for PCBs over the adjacent Southern Ocean, probably due to the importance of long-range atmospheric transport and atmospheric deposition modulating the atmospheric occurrence of PCBs.

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Fung, Vincent WC, and Kam Chuen Yung. "An intelligent approach for improving printed circuit board assembly process performance in smart manufacturing." International Journal of Engineering Business Management 12 (January 1, 2020): 184797902094618. http://dx.doi.org/10.1177/1847979020946189.

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The process of printed circuit board assembly (PCBA) involves several machines, such as a stencil printer, placement machine and reflow oven, to solder and assemble electronic components onto printed circuit boards (PCBs). In the production flow, some failure prevention mechanisms are deployed to ensure the designated quality of PCBA, including solder paste inspection (SPI), automated optical inspection (AOI) and in-circuit testing (ICT). However, such methods to locate the failures are reactive in nature, which may create waste and require additional effort to be spent re-manufacturing and inspecting the PCBs. Worse still, the process performance of the assembly process cannot be guaranteed at a high level. Therefore, there is a need to improve the performance of the PCBA process. To address the aforementioned challenges in the PCBA process, an intelligent assembly process improvement system (IAPIS) is proposed, which integrates the k-means clustering method and multi-response Taguchi method to formulate a pro-active approach to investigate and manage the process performance. The critical process parameters are first identified by means of k-means clustering and the selected parameters are then used to formulate a set of experimental studies by using the multi-response Taguchi method to optimize the performance of the assembly process. To validate the proposed system, a case study of an electronics manufacturer in the solder paste printing process was conducted. The contributions of this study are two-fold: (i) pressure, blade angle and speed are identified as the critical factors in the solder paste printing process; and (ii) a significant improvement in the yield performance of PCBA can be achieved as a component in the smart manufacturing.

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Yao, Min, Zhongjian Li, Xingwang Zhang, and Lecheng Lei. "Polychlorinated Biphenyls in the Centralized Wastewater Treatment Plant in a Chemical Industry Zone: Source, Distribution, and Removal." Journal of Chemistry 2014 (2014): 1–10. http://dx.doi.org/10.1155/2014/352675.

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Polychlorinated biphenyls (PCBs) could be dissolved in wastewater or adsorbed on particulate. The fate of PCBs in wastewater is essential to evaluate the feasibility of wastewater treatment processes and the environmental risk. Here dissolved and adsorbed concentrations of twenty concerned PCB congeners and total PCBs have been measured in the centralized wastewater treatment plant of a chemical industry zone in Zhejiang, China. It was found that the dyeing chemical processes were the main source of PCBs, which contributed more than 13.6%. The most abundant PCB was PCB-11 in the liquid and solid phase of each treatment stage, accounting for more than 60% of the total 209 PCBs. Partitioning behavior of PCBs between the dissolved and adsorbed phases suggested that Di-CBs were the dominant isomers (>70%) and more than 89.8% of them was adsorbed on the particles and sludge. The total removal efficiency of∑209 PCBs was only 23.2% throughout the whole treatment process. A weak correlation was obtained between the individual PCB concentration and their log Kowin primary sedimentation, anaerobic hydrolysis, aerobic bioprocess stage, and the whole treatment process.

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Zhang, Min, and Shi Bin Xia. "PCBs Removing in Aged Landfill Leachate by an Innovative Biofilm Reactor with Biomass Carriers - Luffa Sponges." Applied Mechanics and Materials 670-671 (October 2014): 253–57. http://dx.doi.org/10.4028/www.scientific.net/amm.670-671.253.

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PCBs removal in the aged leachate by a new combination process based on an innovative biofilm reactor with natural fiber media, combined coagulation with a two-staged sequencing batch biofilm reactor with Luffa Sponges (LS) as the biomass carriers (LS-SBBR), was studied in this paper. The results indicated that the total PCBs removal in the aged leachate was 51.97%, and the PCBs removals are mainly achieved by the removal of trichlorobiphenyls, the PCBs contents in sludge in the two-staged LS-SBBR were consistent with the conclusion that the PCBs removal in liquid phase of the second LS-SBBR was higher than that of the first LS-SBBR.

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Marushka, Lesya, Xuefeng Hu, Malek Batal, Constantine Tikhonov, Tonio Sadik, Harold Schwartz, Amy Ing, Karen Fediuk, and Hing Man Chan. "The relationship between dietary exposure to persistent organic pollutants from fish consumption and type 2 diabetes among First Nations in Canada." Canadian Journal of Public Health 112, S1 (June 2021): 168–82. http://dx.doi.org/10.17269/s41997-021-00484-w.

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Abstract Objective We previously examined the associations between dietary dichlorodiphenyldichloroethylene (DDE) and polychlorinated biphenyls (PCBs) intake from fish consumption and type 2 diabetes (T2D) prevalence in Ontario and Manitoba. This study aims to further explore the relationship in a regionally representative sample of First Nations adults living on-reserve across Canada. Methods Dietary, health and lifestyle data collected by the cross-sectional First Nations Food, Nutrition and Environment Study (2008–2018) were analyzed. This participatory study included 6091 First Nations adult participants who answered questions on T2D. The consumption of locally caught fish was estimated with a food frequency questionnaire. A total of 551 samples from 96 fish species were collected and analyzed for the presence of DDE and PCBs. The associations between fish and dietary DDE/PCBs intake with self-reported T2D were investigated using multiple logistic regression models adjusted for confounders. Results Dietary exposure to DDE (>2.11 ng/kg/bw) and PCBs (>1.47 ng/kg/bw) vs no exposure was positively associated with T2D with ORs of 2.33 (95% CI: 1.24–4.35) for DDE and 1.43 (95% CI: 1.01–3.59) for PCBs. The associations were stronger among females (DDE OR = 3.11 (1.41–6.88); PCBs OR = 1.76 (1.10–3.65)) and older individuals (DDE OR = 2.64 (1.12–6.20); PCBs OR = 1.44 (1.01–3.91)) as compared with males and younger participants. Also, significant dose-response relationships were found for fish consumption in females only. Conclusion This study confirms our previous findings that dietary DDE/PCBs exposure may increase the risk of T2D. The effect of DDE/PCBs from fish consumption is driven by geographical differences in DDE/PCBs concentrations in fish and by the amount of fish consumed, and is more prominent in females than in males.

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Hiraoka, Yoshinori, Tohru Yamada, Keiko Tone, Yutaka Futaesaku, and Kazuhide Kimbara. "Flow Cytometry Analysis of Changes in the DNA Content of the Polychlorinated Biphenyl Degrader Comamonas testosteroni TK102: Effect of Metabolites on Cell-Cell Separation." Applied and Environmental Microbiology 68, no. 10 (October 2002): 5104–12. http://dx.doi.org/10.1128/aem.68.10.5104-5112.2002.

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ABSTRACT Flow cytometry was used to monitor changes in the DNA content of the polychlorinated biphenyl (PCB)-degrading bacterium Comamonas testosteroni TK102 during growth in the presence or absence of PCBs. In culture medium without PCBs, the majority of stationary-phase cells contained a single chromosome. In the presence of PCBs, the percentage of cells containing two chromosomes increased from 12% to approximately 50%. In contrast, addition of PCBs did not change the DNA contents of three species that are unable to degrade PCBs. In addition, highly chlorinated PCBs that are not degraded by TK102 did not result in a change in the DNA content. These results suggest that PCBs did not affect the DNA content of the cells directly; rather, the intermediate metabolites resulting from the degradation of PCBs caused the increase in DNA content. To study the effect of intermediate metabolites on the DNA content of the cells, four bph genes, bphA1, bphB, bphC, and bphD, were disrupted by gene replacement. The resulting mutant strains accumulated intermediate metabolites when they were grown in the presence of PCBs or biphenyl (BP). When the bphB gene was disrupted, the percentage of cells containing two chromosomes increased in cultures grown with PCBs or BP. When grown with BP, cultures of this mutant accumulated two intermediate metabolites, 2-hydroxybiphenyl (2-OHBP) and 3-OHBP. Addition of 2- or 3-OHBP to a wild-type TK102 and non-PCB-degrading species culture also resulted in an increase in the percentage of cells containing two chromosomes. Electron microscopy revealed that cell-cell separation was inhibited in this culture. This is the first report that hydroxy-BPs can inhibit bacterial cell separation while allowing continued DNA replication.

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Rissy, Yafet Yosafet Wilben. "Reconceptualizing the Concept of Corporate Governance and its Goals in People’s Credit Banks in Indonesia." Yuridika 36, no. 1 (January 1, 2021): 263. http://dx.doi.org/10.20473/ydk.v36i1.18235.

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This Article examines the concept of corporate governance and its goals in People’s Credit Banks (PCBs). In 2015, Indonesian Financial Services Authority (IFSA) issued two main regulations on corporate governance and risk management for People’s Credit Banks (PCBs). This investigation shows that in these two regulations ISFA simply defines corporate governance as the implementation of transparency, accountability, responsibility, independence and fairness (TARIF) principles by PCBs. Basically, such kind of conceptualization is not appropriate as it does not define the concept of corporate governance itself, but rather, it just reaffirms the general principles of good corporate governance. Meanwhile, IFSA does not clearly provide the goals of corporate governance in PCBs. It is recommended that IFSA should reconceptualize the definition of corporate governance by focusing more on the function of PBCs boards. Meanwhile, the goals of corporate governance in PCBs should deal more with the achievement of long-term success of PCBs.

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Shen, Dong Sheng, Xiao Qing Tao, Chen Chao Shen, Jia Li Shentu, and Mei Zhen Wang. "Antioxidant Defense Enzymes Response Following Polychlorinated Biphenyls Exposure to Eisenia fetida in Actual Polluted Soil." Advanced Materials Research 1010-1012 (August 2014): 142–46. http://dx.doi.org/10.4028/www.scientific.net/amr.1010-1012.142.

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The responses of antioxidant systems after exposing Eisenia fetida to actual soil contaminated with PCBs were investigated. Among antioxidant enzymes, the primary response to early PCBs exposure can be attributed to catalase (CAT) and peroxidase (POD). These two enzymes could have a combined effect on fighting damage by reactive oxygen species. An obvious increase in the activity of CAT was recorded at 4 mg kg-1 compared to the control throughout the whole test days. PCBs exposure caused changes in POD activity in 2d and 4d. However, the activity of POD in E. fetida tissues changed little with PCBs concentrations in day 8 and 16d. Superoxide dismutase (SOD) changed little with PCBs in different time. The results suggest that the variations in CAT and POD of E. fetida could be used as early responsive biomarkers for oxidative stress caused by PCBs in a soil environment.

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Kastanek, F., P. Kastanek, K. Demnerová, and Y. Maléterová. "Decontamination of wastewater contaminated by polychlorinated biphenyls (PCBs)." Water Science and Technology 50, no. 2 (July 1, 2004): 131–38. http://dx.doi.org/10.2166/wst.2004.0107.

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Wastewater contaminated by PCBs obtained from three different sources was treated at both laboratory and pilot plant scale conditions by ultraviolet oxidation of organics at the presence of hydrogen peroxide after partial adsorption of impurities and PCBs on activated carbon and/or activated bentonite. The procedure was conducted both with and without a Fe(II) catalyst and considerable reduction of PCB concentration was achieved in both cases. In pilot plant scale experiments, activated carbon polishing step followed UV oxidation. The following three types of contaminated waste water were examined: a) aqueous extracts originated in the course of clean-up of contaminated soil by extraction with aqueous solvents. Concentrations of PCBs in extracts were between 1 μg/L to 3,000 μg/L; b) wastewater condensates originated in the process of thermal desorption of PCB from soils. Concentrations of PCBs in condensates were between 300 μg/L and 5,000 μg/L. c) underground water contaminated by PCBs extracted from the sites of old contamination. The content of PCBs was up to 50,000 ng/L. Biodegradation of PCBs with a mixture of indigenous soil bacteria (selected strains of Pseudomonas and Acitenotobacter) was also tested. It was carried out in a reactor with volume of 1.5 m3 by application of the bacteria in a slurry of bentonite with adsorbed PCBs.

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Luo, Jie, Zhao Jie Cui, Shi Yong Du, and Guo Lan Fan. "Temporal Variation and Meteorological Dependence of Polychlorinated Biphenyls in Atmospheric PM₁₀ of Jinan, China." Advanced Materials Research 779-780 (September 2013): 1250–53. http://dx.doi.org/10.4028/www.scientific.net/amr.779-780.1250.

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s. To explore the PCB pollution characteristics in the airborne particulate matter, seven indicative polychlorinated biphenyls (PCBs) in atmospheric PM10 were determined weekly in Jinan, China. PCB concentrations, profiles, temporal distribution pattern and the correlations between Σ7PCBs and the meteorological conditions were analyzed, aiming to quantify the pollution level of PCBs in urban air. All the samplers were extracted by accelerated solvent extraction (ASE) and analyzed by gas chromatography (GC). The monthly concentrations of Σ7PCBs were 81.4-2335.2 fg/m3. A distinct seasonal variation of PM10-associated PCBs exhibited. Higher concentrations of PCBs in cold weather than warm weather was found. PCB28 and PCB52 were the major components of PM10-associated PCBs in cold weather, while PCB 118 and PCB 180 dominated in warm weather. The fresh emission sources in cold weather, such as the burning of coal for domestic heating, were suggested to be a major influence factor. A significant correlation (p<0.05) was found between the total PCB congeners and atmospheric pressure. Heavy rainfall can also impact PM10-PCBs significantly. The weak correlation coefficient between atmospheric PCBs and wind speed suggested that the inefficient dispersion and no significant pollution sources around.

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Sciarrillo, Rosaria, Alessandra Falzarano, Vito Gallicchio, Aldo Mileo, and Maria De Falco. "Toxic Effects on Thyroid Gland of Male Adult Lizards (Podarcis Siculus) in Contact with PolyChlorinated Biphenyls (PCBs)-Contaminated Soil." International Journal of Molecular Sciences 23, no. 9 (April 26, 2022): 4790. http://dx.doi.org/10.3390/ijms23094790.

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Skin exposure is considered a potentially significant but little-studied pathway for PolyChlorinated Biphenyls uptake in terrestrial reptiles. In this study, a native Italian lizard, Podarcis siculus, was exposed to PCBs-contaminated soil for 120 days. Tissues distribution of PCBs, thyroid hormone levels, and thyroid histo-physiopathology were examined. The accumulation of PCBs in skin, plasma, liver, kidney, and brain were highest at 120 days. The alteration of triiodothyronine (T3) and thyroxine (T4) levels after different concentrations and times to exposure of PCBs was accompanied by the changes in the hormones involved in the hypothalamus-pituitary-thyroid (HPT) axis, namely Thyrotropin Releasing Hormone (TRH) and Thyroid Stimulating Hormone (TSH). Moreover, hepatic levels of deiodinase II (5′ORDII) and content of T3 were positively correlated to exposure to PCBs. These results indicated that in lizards, PCBs exposure through the skin has the potential to disrupt the thyroid endocrine system. Overall, the observed results indicate that PCBs could be associated with changes in thyroid homeostasis in these reptiles, through direct interactions with the metabolism of T4 and T3 through the HPT axis or indirect interactions with peripheral deiodination.

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Li, Zhi Yong, Lan Chen, Yu Heng Quan, and Yan Song. "Pcbs in Soils around an Old Electric Transformer Factory in North China." Applied Mechanics and Materials 587-589 (July 2014): 550–53. http://dx.doi.org/10.4028/www.scientific.net/amm.587-589.550.

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The 28 surface soil samples (0-10 cm) were collected from the urban area of Baoding city nearby an old electric transformer factory for analysis of 84 PCB congeners. Total PCBs concentrations ranged from 0.69 to 11.15 ng/g (mean: 3.62 ng/g). The PCBs concentration (5.72 ng/g) for sampling sites in the vicinity (0-2.5 km) of the transformer factory was higher than that (2.96 ng/g) for other sampling sites. Compositional patterns of individual congener and homologs were similar to those of Chinese transformer oils. The top five congeners were PCB-6, 18, 22, 33 and 31/28 among the identified PCBs. Low chlorinated PCBs (di-to tetra-CBs) accounted for 69.58% of total PCBs concentrations and the predominant PCB homologs were tri-CBs (46.38%), penta-CBs (13.73%) and di-CBs (9.47%), respectively. Principal component analysis showed that technical formulations such as Chinese transformer oil, Aroclor1242, 1016, KC-300 and A-30 were the main sources of soils PCBs from Baoding city. The TEQ concentrations based on ten dioxin-like PCBs ranged from 0 to 26.0986 ng/kg with the mean value as 7.3336 ng/kg.

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Zhang, Yi, Xiaozhong Song, and Sujie Zhao. "Evidences from China: Impacts of Information Asymmetry, Budgetary Participation, Emphasis, Procedural Justice, Interactive Justice, Clarity and Difficulty of Budgetary Goals on Subordinate Manager Propensity of Creating Budgetary Slack." Journal of Computational and Theoretical Nanoscience 14, no. 1 (January 1, 2017): 207–20. http://dx.doi.org/10.1166/jctn.2017.6150.

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Subordinate managers’ propensities of creating budgetary slack (PCBS) will induce the dysfunction of budget system. This paper analyzes the inducements of PCBS, including information asymmetry, budgetary participation, budgetary emphasis, procedural justice, interactive justice, clarity and difficulty of budgetary goal, and tries to find out their ways affecting PCBS. On the basis of the researches of Dunk, Onsi, Kren, Kenis, Van der Stede, and Moorman and Kenis, we designed a 6-point 33-item Likert scale and formulated eight research variables and a control variable. We have investigated data of 28 Chinese enterprises and gotten 269 valid samples. Our empirical evidences suggest PCBS is positively affected by information asymmetry and budgetary emphasis, and has been negatively affected by budgetary participation from single factor, and given high (low) level of participation, high (low) subordinate-superior information asymmetry and high (low) emphasis on budget standards, PCBS is high (low). These conclusions support the theoretic hypothesis of Dunk’s and strengthen the notes of Dunk and Perera. However, our results are different from the empirical result of Dunk and Chong et al. (2003). It is found that interactive justice is negatively related to PCBS, and difficulty of budgetary goal is positively related to PCBS.

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Liu, Fang, Guang Meng, and Mei Zhao. "Viscoelastic Influence on Dynamic Properties of PCB Under Drop Impact." Journal of Electronic Packaging 129, no. 3 (March 15, 2007): 266–72. http://dx.doi.org/10.1115/1.2753910.

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Dynamic properties of printed circuit board (PCB) assembly under drop impact are investigated when viscoelasticity of substrate materials is considered. The main materials of a PCB substrate are macromolecule resins, which are typical viscoelastic materials. From the viewpoint of viscoelasticity, the dynamics of PCBs under drop impact is analyzed based on mass-damping-spring, beam, and plate theories. It is demonstrated that the viscoelasticity of a PCB has distinct influences on the dynamic properties of PCBs under board-level drop impact. When there is an increase in the viscosity of substrate materials, the damping coefficients of PCBs would rise, its deflection and acceleration responses could diminish faster, and the maximum deflection of PCBs would become smaller. Meanwhile, with the same viscosity and drop impact conditions, a larger plate would produce a bigger deflection response. Therefore, drop impact reliability could be enhanced by choosing substrate material of larger viscoelasticity and reducing properly the size of PCBs. Dynamic analysis of PCBs under drop impact not only contributes to perfecting theoretical research, but also provides a reference for the choice of substrate materials and reliability design of PCBs when electronic products are devised.

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Huang, P., S. L. Gong, T. L. Zhao, L. Neary, and L. A. Barrie. "GEM/POPs: a global 3-D dynamic model for semi-volatile persistent organic pollutants – Part 2: Global transports and budgets of PCBs." Atmospheric Chemistry and Physics 7, no. 15 (August 1, 2007): 4015–25. http://dx.doi.org/10.5194/acp-7-4015-2007.

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Abstract. Global transports and budgets of three PCBs were investigated with a 3-D dynamic model for semi-volatile persistent organic pollutants – GEM/POPs. Dominant pathways were identified for PCB transports in the atmosphere with a transport flux peaking below 8 km for gaseous and 14 km for particulate PCB28, and peaking below 4 km for gaseous and 6 km for particulate PCB180. The inter-continental transports of PCBs in the Northern Hemisphere (NH) are dominated in the zonal direction with their route changes regulated seasonally by the variation of westerly jet. The transport pathways from Europe and North Atlantic contributed the most PCBs to the Arctic. Inter-hemispheric transports of PCBs originated from the regions of Europe, Asia and North America in three different flow-paths, accompanying with easterly jet, Asian monsoon winds and trade winds. PCBs from the Southern Hemisphere (SH) could also be exported into the NH. According to the PCB emissions of year 2000, Europe, North America and Asia are the three largest sources of the three PCBs, contributing to the global background concentrations in the atmosphere, soil and water. Globally, PCB28 in soil and water has become a comparable source to the anthropogenic emissions while heavier PCBs such as PCB153 and 180 are still transporting into soil and water. For all three congeners, particulate PCBs are concentrated in the higher levels than gaseous PCBs. More than half of the particulate PCB28 could reach up to the stratosphere, while most of the heavier counter-parts (PCB153 and PCB180) are stored in the troposphere including boundary layer with more than 99% gaseous PCB180 below 6 km.

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Kučerová, Petra, Martina Macková, Ludmila Poláchová, Jiří Burkhard, Kateřina Demnerová, Jarmila Pazlarová, and Tomáš Macek. "Correlation of PCB Transformation by Plant Tissue Cultures with Their Morphology and Peroxidase Activity Changes." Collection of Czechoslovak Chemical Communications 64, no. 9 (1999): 1497–509. http://dx.doi.org/10.1135/cccc19991497.

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The ability of plant cells cultivated in vitro to metabolize polychlorinated biphenyls (PCBs) was correlated with the morphology of the cultures tested as models for phytoremediation studies. More differentiated cultures showed generally higher transformation capacity. The ability of plant cells to transform PCBs is connected to their viability in the presence of PCBs and their behaviour can be positively correlated with the production of intracellular and extracellular peroxidases. The cultures with high PCB-transforming activity proved to exhibit high peroxidase activity in the presence of PCBs while those with low ability to metabolize PCB showed a decrease of the enzyme activity in the presence of PCBs. Experiments with propylgallate were used to distinguish the ratio of involvement of peroxidases in PCB metabolism.

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Meng, Yongjun, Yongjie Liao, Zhirong Liu, Jing Chen, Xiaolong Yang, and Hongliu Rong. "Study on Rheological Properties of Bituminous Binders and Mixtures Containing Waste Printed Circuit Boards (PCBs) and SBR Compound Modified Bitumen." Materials 14, no. 7 (March 30, 2021): 1697. http://dx.doi.org/10.3390/ma14071697.

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Improper handling of waste printed circuit boards (PCBs) can cause serious pollution to the water and soil environments. In order to explore a new method of recycling waste PCBs, this study investigated the effect of PCBs and butadiene styrene rubber (SBR) on the rheological properties of neat bitumen. The dynamic shear rheological (DSR) test was used to study the effect of different PCB contents on the high-temperature rheological properties of SBR-modified bitumen. Fluorescence microscopy and Fourier-transform infrared spectroscopy were used to study the microstructure change law and modification mechanism of PCB and SBR composite modified bitumen. Finally, the feasibility of the bitumen properties was verified through a test of the bituminous mixture properties. The DSR test results showed that the addition of PCBs improves the elastic recovery modulus, dynamic shear modulus, and rutting factor of SBR-modified bitumen, indicating that the high-temperature properties were improved. Infrared spectroscopy analysis revealed that a new absorption peak was generated in the infrared spectrum of the compound bitumen after the addition of PCBs, and the intensity of the original absorption peak also changed, indicating that PCBs and SBR-modified bitumen were mainly physically blended and accompanied by a weak chemical reaction. It was further found that the absorption peak of the unsaturated C=C double bond was significantly enhanced, and the increase in the content of the unsaturated bond C=C in the main chain of the polymer significantly increases the stiffness of the bitumen. Macroscopically, the high-temperature rutting resistance was improved to a certain extent. The fluorescence diagram shows that when PCBs do not exceed 10%, the PCBs can form a homogeneous structure and be dispersed in SBR-modified bitumen. The road test of PCBs and SBR composite modified bituminous mixtures showed that PCBs can significantly improve the rutting resistance and water stability of SBR-modified bitumen at high temperatures at the recommended optimum content. The crack resistance at low temperatures is weakened but still meets actual engineering requirements. The correlation analysis between the properties of bitumen and bituminous mixtures is carried out based on grey correlation theory. The results show that the index of modified bitumen has a very good guiding effect on the bituminous mixture properties. The development of PCBs and SBR composite-modified bitumen provides a new practical method for recycling waste PCBs.

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39

HIRONAKA, Hiromi. "Smell of PCBs." Journal of Japan Association on Odor Environment 36, no. 6 (2005): 316–22. http://dx.doi.org/10.2171/jao.36.316.

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40

Myers, J. P., and T. Colborn. "Regulation of PCBs." Science 253, no. 5026 (September 20, 1991): 1334. http://dx.doi.org/10.1126/science.253.5026.1334.b.

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Robertson, Larry W., Eric M. Silberhorn, Arthur L. Frank, and Howard P. Glauert. "Regulation of PCBs." Science 253, no. 5026 (September 20, 1991): 1334. http://dx.doi.org/10.1126/science.253.5026.1334.a.

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O'Shea, Thomas J. "Regulation of PCBs." Science 253, no. 5026 (September 20, 1991): 1334. http://dx.doi.org/10.1126/science.253.5026.1334.c.

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43

Casati, Lavinia. "Epigenetics and PCBs." Endocrine Disruptors 1, no. 1 (October 2013): e27347. http://dx.doi.org/10.4161/endo.27347.

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KREGTING, W. T. "DREAMS ABOUT PCBs." Circuit World 20, no. 4 (March 1994): 2. http://dx.doi.org/10.1108/eb046267.

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Robertson, L. W., E. M. Silberhorn, A. L. Frank, and H. P. Glauert. "Regulation of PCBs." Science 253, no. 5026 (September 20, 1991): 1334. http://dx.doi.org/10.1126/science.253.5026.1334.

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46

MYERS, J. P., and T. COLBORN. "Regulation of PCBs." Science 253, no. 5026 (September 20, 1991): 1334. http://dx.doi.org/10.1126/science.253.5026.1334-a.

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O'SHEA, T. J. "Regulation of PCBs." Science 253, no. 5026 (September 20, 1991): 1334. http://dx.doi.org/10.1126/science.253.5026.1334-b.

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Fawcett, HowardH. "PCBs the Environment." Journal of Hazardous Materials 31, no. 1 (June 1992): 89–90. http://dx.doi.org/10.1016/0304-3894(92)87042-e.

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Huang, P., S. L. Gong, T. L. Zhao, L. Neary, and L. A. Barrie. "GEM/POPs: a global 3-D dynamic model for semi-volatile persistent organic pollutants – Part 2: Global transports and budgets of PCBs." Atmospheric Chemistry and Physics Discussions 7, no. 2 (March 16, 2007): 3837–57. http://dx.doi.org/10.5194/acpd-7-3837-2007.

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Abstract. Global transports and budgets of three PCBs were investigated with a 3-D dynamic model for semi-volatile persistent organic pollutants – GEM/POPs. Dominant pathways were identified for PCB transports in the atmosphere with a peak transport flux below 8 km and 14 km for gaseous and particulate PCB28, 4 km and 6 km for gaseous and particulate PCB180. The inter-continental transports of PCBs in the Northern Hemisphere (NH) are dominated in the zonal direction with their route changes seasonally regulated by the variation of westerly jet. The transport pathways from Europe and North Atlantic to the Arctic contributed the most PCBs over there. Inter-hemispheric transports of PCBs originated from the regions of Europe, Asia and North America in three different flow-paths, accompanying with easterly jet, Asian monsoon winds and trade winds. PCBs from the Southern Hemisphere (SH) could export into the NH. According to the PCB emissions of year 2000, Europe, North America and Asia are the three largest sources of the three PCBs, contributing to the global background concentrations in the atmosphere and soil and water. Globally, PCB28 in soil and water has become a comparable source to the anthropogenic emissions while heavier PCBs such as PCB153 and 180 are still transporting into soil and water. It is found that lighter PCBs have more long range transport potentials than their heavier counter-parts in the atmosphere.

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Li, Chunxia, Hong Xing, Qiaoyu He, Jing Liu, Hong Liu, Yue Li, and Xiaopeng Chen. "Network Toxicology Guided Mechanism Study on the Association between Thyroid Function and Exposures to Polychlorinated Biphenyls Mixture." BioMed Research International 2022 (September 27, 2022): 1–17. http://dx.doi.org/10.1155/2022/2394398.

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Polychlorinated biphenyls (PCBs) are persistent and highly toxic pollutants, which can accumulate in organisms and produce toxic effects, especially damaging the function of thyroid hormones. So far, the molecular mechanism of PCBs mixture and their metabolites interfering with thyroid hormones has not been studied thoroughly except for individual compounds. In this study, PubMed, Web of Science, and STITCH databases were used to search PCBs and their corresponding target proteins. The intersection of PCBs and thyroid hormone dysfunction target proteins was obtained from GeneCards. The “compounds-targets-pathways” network was constructed by Cytoscape software. And KEGG and Go analyses were performed for key targets. Finally, molecular docking was used to verify the binding effect. Four major active components, five key targets, and 10 kernel pathways were successfully screened by constructing the network. Functional enrichment analysis showed that the interference was mediated by cancer, proteoglycans, PI3K-Akt, thyroid hormone, and FoxO signaling pathways. The molecular docking results showed that the binding energies were less than -5 kcal·mol-1. PCBs and their metabolites may act on the key targets of MAPK3, MAPK1, RXRA, PIK3R1, and TP53. The toxic effect of sulfated and methyl sulfone PCBs is greater. The method of screening targets based on the simultaneous action of multiple PCBs can provide a reference for other research. The targets were not found in previous metabolite toxicity studies. It also provides a bridge for the toxic effects and experimental research of PCBs and their metabolites in the future.

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Journal articles on the topic 'PCBs'

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