The metabolism and distribution of three commonly occurring PCB congeners, 4,4'-dichlorobiphenyl (4-DCB), 2,2',3,3',6,6'-hexachlorobiphenyl (236-HCB) and 2,2',4,4',5,5'-hexachlorobiphenyl (245-HCB), each displaying different structural features, were investigated at their principal metabolic site, the hepatocyte. Hepatocytes, isolated from male Sprague-Dawley rats (200-250 g) by collagenase perfusion, were suspended in medium 199 and maintained at 37°C in a gyratory shaker. The radiolabeled ¹⁴C-PCB congeners were added to the hepatocyte suspensions as a DMSO-albumin mixture. Each congener was rapidly taken up by the cells with less than 10% of the congener remaining in the medium. The congeners accumulated within the hepatocytes without being fully metabolized. Metabolism followed first order Michaelis-Menten kinetics for 20 min and plateaued by 90 min at which point only 32% of 4-DCB (0.01-100 uM) and 60% of 236-HCB (0.01-100 uM) was metabolized, while 245-HCB (0.1-200 uM) was not metabolized. Readdition of congener once metabolism had plateaued resulted in a reinitiation of metabolism with the same proportion of metabolites produced indicating that product inhibition was not the cause for the plateau. A partitioning of the PCB congeners within subcellular compartments and binding to cytosolic proteins influenced the extent of metabolism by decreasing the availability of congener for the drug metabolizing enzymes, cytochrome P-450. Spectral binding studies further revealed that the ability of a PCB congener to bind to the cytochrome P-450 system correlated with the extent of metabolism observed, with 236-HCB 4-DCB 245-HCB. The metabolic potential of the PCB congeners was influenced by both the affinity of the congener for cytochrome P-450 and the partitioning of congener within the hepatocyte, and not by product inhibition.

All major pollution incidents in contemporary Japan have spawned victims' protest movements. This dissertation is a case study of one such movement which emerged in the late 1960s among thousands of persons poisoned by polychlorinated biphenyls (PCBs) that had accidentally leaked into their cooking oil. The study describes the evolution of victims' response to the disaster, beginning with the initial outbreak of symptoms, their efforts to uncover the cause of these symptoms and to receive appropriate medical treatment, and their organization of a movement to seek redress in the form of an apology from the manufacturer of the oil, reform by industry and government, and compensation. Victims utilized a variety of tactics before finally resorting to litigation in attempts to achieve their goals. Theirs was the largest pollution case ever tried in Japan. The final section of the study focuses on a major leader of the victims' movement, Kamino Ryuzo. A spokesman for the victims, Kamino, a retired miner and Christian convert, became a kind of anti-pollution ideologue. An account of his intellectual and religious odyssey and of the unique tactics forged by his family to cope with their predicament provides a perspective on victims' movements not found elsewhere. The study concludes that victims became their own advocates only after the government and industry failed to accept responsibility for pollution; that the victims went to court only reluctantly after all other avenues for redress were closed to them; and that, although they won their case, they felt it was a Pyrrhic victory, because they failed to attain all their goals, such as reform of industrial policy. Research is based on participation-observation, interviews, written materials produced by pollution victims and their supporters, and published newspaper accounts.

Polychlorinated Biphenyls (PCBs) are hazardous and toxic chemicals to both humans and animals. In the late 1960’s PCBs were discovered to be a harmful pollutant which could cause environmental contamination due to its slow degradation and even trace amounts of PCBs were regarded as toxic to both human and animals. Oil spills are a frequent occurrence at Eskom substations which could contain PCBs. The contaminated sediments which are easily carried away by rain and wind can further contaminate the environment and aquatic bodies. Eskom currently disposes of soil and ballast stones contaminated with PCBs by thermal destruction. This is a costly process as PCBs are regarded as hazardous materials and needs to be safely transported and disposed of at a licensed disposal facility. Based on literature, ozone has been used on a laboratory scale to treat soil contaminated with PCBs with the addition of chemicals such as hexane and acetone which assist in breaking down PCBs. The objective of this study was to evaluate whether ozone without the addition of chemicals could reduce the levels of PCBs present in contaminated soil. In this study, two soil samples and one ballast stone sample were contaminated with 50 ppm, 200 ppm and 600 ppm of PCBs and then exposed to 0.4, 0.5 and 0.6 l/min of ozone for a period of 60 minutes to examine the effects of increasing ozone flow rates on PCB destruction in soil. The results of the experimental tests showed that ozone gas reduced the concentration of PCBs in the soil and ballast stone samples for the different total gas flow rates. The literature study identified that the final products of the ozonation of PCBs are carbon dioxide and water and that any products formed after this process could possibly be degraded by the soil natural microorganisms. Calculations based on the Shin et al. (2004) model proved that ozone was in excess after the ozonation process. The results of the experiments also confirmed this, as the PCB residuals were similar for all three total gas flows, which showed that there was no dependence on the gas flow rates hence, ozone was in excess. The experimental data was then trended with zero, first and second order reaction equations, which showed that the best fit was obtained with the firstorder reaction equation. It is recommended that ozone be used for the treatment of PCB contaminated soil at Eskom substations. / Thesis (M.Sc.Eng.)-University of KwaZulu-Natal, Durban, 2011.

PCBs are persistent organic pollutants that have intentionally and unintentionally (through contamination) been added to mineral insulating oil to improve its insulating and cooling properties within electrical equipment. The Stockholm Convention on Persistent Organic Pollutants (2001) orders the eradication of PCBs from use by 2025. Sodium based dechlorination is a PCB destruction process that is non-thermal, relatively cost effective and allows for the recovery of a reusable end product. A comparative benefits study, contained in chapter 2 of this dissertation, describes the increased financial and environmental impact associated with incinerating large volumes of PCB contaminated mineral oil. The results of the comparative analysis indicate a cost ratio of 1: 2.5, in favour of sodium dechlorination. In addition to the financial benefit, the sodium based PCB dechlorination process is versatile and can be either batched or skid mounted and is typically combined with an oil regeneration step, allowing for transformers to be treated onsite and whilst energised. Eskom is currently considering obtaining the mobile dechlorination unit for the purpose of conducting dechlorination and regeneration on its PCB contaminated transformers while energised. Mineral insulating oil is considered a strategic asset within most industries. Eskom uses mainly uninhibited mineral oil in its older transformers and the effects of PCB dechlorination on the natural inhibitor content of the oil is uncertain. The objective of this study was to investigate the effects of sodium dechlorination on the oxidation stability and thereby indirectly the natural inhibitor content of uninhibited naphthenic based mineral oil. The study involved the dechlorination, regeneration and subsequent chemical analyses of PCB contaminated oils in the PCB ranges <50ppm, 50 to 500 ppm and >500 ppm as stipulated by the Stockholm Convention on Persistent Organic Pollutants (2001). The study confirmed the reduction in oxidation stability and thereby the natural inhibitor content of the mineral oil after sodium dechlorination. Based on the results obtain a preliminary algorithm was established to predict the reduction in oxidation stability after sodium dechlorination, as a function of the PCB concentration prior to dechlorination. This will provide an indirect indication of the rate of natural inhibitor depletion of the oil, based on its exposure to the sodium dechlorination reagents and process conditions. / Thesis (M.Sc.Eng.)-University of KwaZulu-Natal, Durban, 2010.

The purpose of this paper was to combine available peer-reviewed literature on PCB phytoremediation and make direct comparisons using ANCOVA statistics in order to determine if and what plants are presently a viable option for the remediation of PCB contaminated soils. Pumpkin (Curbita pepo cv Howden) consistently had the top root and shoot concentrations, as well as total plant accumulation. Their consistency shows that they can be reliable in the field and the most viable option. Tall fescue and sedge were also top contenders. Due to the small sample size for many plants and accounting for several confounding variables, very few of plant species and groups showed to be significantly better at PCB accumulation. PCB phytoremediation can be used in conjunction with other technologies or as an early action plan to begin decreasing PCB concentration levels as well as contain the PCBs, thereby preventing any release.

A research report submitted to the Faculty of Science, University of the Witwatersrand, in partial fulfilment of the requirements for the degree of Master of Science in Environmental Sciences Johannesburg, 2017. / PCBs are chemical compounds which were synthesised in the laboratory in the 1920s. They are classified under the category of POPs. They were mainly used in electrical equipments and transformers as the insulating material. PCBs were released to the environment in the form of oil spillages, combustion of PCB-containing equipments and others. Its production was banned in the 1970s after its toxic, persistent, bioaccumulative and carcinogenic behaviour was discovered. This study was conducted to determine and monitor the level of PCB in soil contaminated by oil spillages from pole mounted transformers in Polokwane, Limpopo, South Africa after sites have been remediated. Seventy eight soil samples were collected from five sites. The QuEChERS extraction method and GC-MS was used to extract and analyse PCBs. The PCB congeners targeted in this study are PCB-180, PCB-158 and PCB-101. The concentration of PCB-180 ranges between 10.02 and 78.30 μg kg -1, PCB-158 ranges between 3.89 and 45.36 μg kg -1 and PCB-101 ranges between 2.42 and 39.12 μg kg -1. The PCB congener with the highest concentration at all sites is PCB-180 followed by PCB-158 while PCB-101 has the least concentration; this order is consistent in all sampling sites. PCB concentrations after bioremediation were found to be extremely higher than concentrations before bioremediation which suggest that the bioremediation process was not efficient including actual analytical methods used. In comparison to the range of the PCB levels reported in literature, the PCB concentration determined from this study is found within a higher range. The PCBs concentration at all five sites was found to be below the legal limits. / LG2018

Thesis (MTech (Chemistry))--Cape Peninsula University of Technology, 2015. / Immunosensors are analytical devices comprising antibody (Ab) molecules intimately integrated with electronic physicochemical transducers. Abs are responsible for specific recognition of an analyte so called antigen (Ag) while transducers are responsible for the conversion of chemical changes brought about by Ab-Ag interactions into measurable and processable signal. Amongst the many analytical tools, immunosensors have shown outstanding performance in applications in fields such as clinical diagnostics, agricultural purposes and environmental monitoring. They have come in place of the many conventional analytical methods which showed a number of disadvantages; high cost and longer time of operation, and requirement of highly knowledgeable personnel. On the other hand, immunosensors have shown potential to overcome these constraints. Their advantages include possibilities of portability, miniaturization, and simplified procedures. Of the possible fields of immunosensor applications, this study focussed on the environmental aspect. The safety of the environment is good for the well-being even though there are still some environmental threats that exist. Polychlorinated biphenyls (PCBs) have reportedly been found to be some of the potential substances to pose such threats due to their toxic and persistent behaviour. In this study, we have developed an electrochemical immunosensor as an analytical tool for the analysis and monitoring of PCBs. The development was based on the use of silver nanoparticles-doped polyaniline (PANI/Ag NPs) for modification of an electrode as a process for fabrication of the transducer. The PANI/Ag NPs composite was deposited on the glassy carbon (GC) and platinum (Pt) electrodes by oxidative electropolymerization of aniline in the presence of Ag NPs in 1 M HCl using cyclic voltammetry (CV) by ramping the potential from -0.1 to 1.4 V at 50 mV/s. The composite was then characterized and evaluated as a potential material for electrochemical transduction. Evaluation was on electroactivity, which is the main property of interest for materials used in the fabrication of electrochemical devices. The PANI composites were characterized using spectroscopic (FTIR), microscopic (TEM) and electrochemical CV techniques. Results confirmed the formation of PANI in its emeraldine form and the presence of Ag NPs. Characteristic functional groups and peaks of PANI were observed in FTIR and CV respectively. TEM micrograms showed one dimensional nanofibric tubes and crystalline-like structure of the composite. The incorporation of Ag NPs was indicated by the transition from the amorphous (PANI) to crystalline (PANI/Ag NPs) structure accompanied by increase in size as well as smoothness of the tubes. EDS-TEM counts increase of the chlorine (Cl) peaks is due to the closeness of these peaks to those of Ag, thus confirming incorporation of Ag NPs.

Os éteres de bifenilas polibromados (PBDEs) são largamente usados como retardadores de chama e têm sido detectados no sangue humano, tecido adiposo e leite materno devido às suas propriedades físico-químicas e bioacumuladoras e à sua elevada persistência no meio ambiente. Muitos estudos têm relatado toxicidade hepática relacionada à exposição aos PBDEs. Como efeitos citotóxicos são frequentemente associados à disfunção mitocondrial,no presente estudo, investigamos a toxicidade do BDE-47 em mitocôndrias isoladas de fígado de rato. Nos seguintes parâmetros: potencial de membrana mitocondrial, consumo de oxigênio, interação com a membrana mitocondrial, liberação de cálcio, inchamento mitocondrial e os níveis de ATP da suspensão mitocondrial com a finalidade de observar a capacidade do composto em interferir com a bioenergética da organela. Avaliou-se ainda a formação de espécies reativas de oxigênio (ROS), dos níveis de GSH/GSSG, níveis mitocondriais de grupos sulfidrila de proteínas e níveis mitocondriais de NAD(P)H com o intuito de analisar o estado redox mitocondrial. Os congêneres BDE-47 e BDE-99 foram avaliados em concentrações que variaram entre 0,1 e 50 ?mol/L. Os dois congêneres de PBDEsapresentaram toxicidade mitocondrial afetando todos os parâmetros que avaliam a bioenergética mitocondrial culminandoum uma depleção do ATP. Por outro lado, nos ensaios de avaliação do estresse oxidativo os PBDEs estudados não demonstraram qualquer efeito, no entanto, afetaram a cadeia respiratória mitocondrial, o que normalmente reflete em um acúmulo de espécies reativas de oxigênio. Estes resultados são explicados pelo mecanismo de ação destes compostos como retardante de chama, pois durante a combustão os retardantes de chama bromados realizam a neutralização de radicais livres (OHo e Ho). Conclui-se assim que os PBDEs podem levar à disfunção bioenergética e assim induzir a morte celular pela diminuição do ATP. Observou-se ainda que BDE-47 apresentou maior toxicidade do que o BDE-99 sobre os parâmetros estudados. / Polybrominated biphenyls ethers (PBDE) , widely used as flame retardants, have been detected in human blood, adipose tissue and breast milk due to their physicochemical and high bioaccumulative properties and environmental persistence. Many studies have reported liver toxicity related to exposure to PBDEs. As cytotoxic effects are often associated with mitochondrial dysfunction,in the present study, we investigated the toxicity of the BDE-47 and BDE-99 on isolated rat liver mitochondria. Assessing mitochondrial membrane potential, oxygen consumption, interaction with the mitochondrial membrane, calcium release, mitochondrial swelling and ATP levels of the mitochondrial suspension in order to observe the ability of the compounds to interfere with the bioenergetic organelle, and the formation of reactive oxygen species (ROS), GSH/GSSG levels, mitochondrial sulfhydryl groups and levels of mitochondrial NAD(P)H in order to analyze mitochondrial redox state. The congeners BDE-47 and BDE -99 were evaluated at concentrations ranging between 0.1 and 50 ?mol/L. Both PBDEs congeners showed mitochondrial toxicity affecting all parameters that assess mitochondrial bioenergetics and culminating with ATP depletion. On the other hand, no effect was observed in tests assessing oxidative stress, although they were able to inhibit the mitochondrial respiratory chain, which is usually reflected in an accumulation of reactive oxygen species. These results are explained by the mechanism of action of this compounds as flame retardants, because during the combustion brominated flame retardants perform the neutralization of free radicals (OHo and Ho). It follows that PBDEs can lead to mitochondrial dysfunction and thus induce bioenergetic cell death. It was also observed that The BDE-47 showed higher toxicity than BDE-99 in the studied model

No description available.

Os bifenilos policlorados (PCBs) são compostos organoclorados que apresentam 209 congêneres sendo que alguns deles são muito tóxicos. Foram produzidos por mais de 30 anos sendo utilizados principalmente no setor eletroeletrônico. Devido à legislação brasileira não prever substituição de equipamentos, ainda em funcionamento, que contenham PCBs estes podem tomar-se fontes potenciais de contaminação no ambiente. Neste aspecto a região do Vale do Paraiba, por ter um parque industrial diversificado (químico, eletrônico e mecânico) iniciado na década de 50, pode apresentar essas fontes. O rio Paraíba do Sul é o principal recurso hídrico sendo utilizado para captação de água para abastecimento e também como receptor de efluentes industriais e esgotos domésticos. Nele também é praticada a pesca de subsistência pela população ribeirinha. Devido às características de bioconcentração no fígado de peixe por organoclorados, decidiu-se utilizá-lo como bioindicador. Assim pode ser verificada a presença de PCBs na região avaliando-se os níveis de contaminação que podem colocar em risco as populações ribeirinhas. Na metodologia analítica proposta, foram encontrados de 48 a 159 ng/g de PCBs totais para a traíra e 12 a 34 ng/g de PCBs totais para o mandi. A recuperação alcançada foi na faixa de 50 a 100%. Os valores do limite de detecção para os 13 congêneres estudados se encontraram na faixa de 1 a 3 ng/g. Os congêneres mais genotóxicos (PCB 77 e 126) foram encontrados principalmente na traira com 20 &plusmn; 9 ng/g (PCB 77) e 21 &plusmn; 3 ng/g (PCB126), enquanto que o mandi apresentou principalmente o PCB 77 com 8 &plusmn; 2 ng/g. Estas avaliações são preliminares e necessitam de maiores estudos para se determinar a extensão do grau de contaminação e as possíveis fontes de contaminação por estes compostos. / The chlorinated biphenyls are organochlorinated compound with around 209 congeners some them are very toxic. They were produced during 30 years and used mainly in the eletronic equipment (transformers and capacitors). Brazilian legislation don\'t obligate the substitution of equipaments containing PCBs that are still being used. So this could be a signifincat source of environrnent contamination. The industries have settled the Paraíba Valley since 50\'s that can represent the major source of PCBs. The South Paraíba river main hidric source that has been used caption for water suplly and subsistent fishing. It receives also industrial efluents and domestic sewer. In spite of bioconcentration characteristics of organochIorinated in fishes\'liver, this organ was decided to be used as bioindicator. PCB\' s level can be avaliated indiretly, analysing the exposure of some species of fishes, and arevall contamination around the fish population. From this proposed analytical method total PCBs from traira here found nearly 32 to 143 ng/g in liver and 8 to 26 ng/g in mandi\'s liver. The aproached recuperation were about 50 to 100%, the limit detection for these 13 congeners were around 1 to 3ng/g. The most genotoxic congeners were found in traira (PCB 77 20 &plusmn; 9ng/g and PCB 12621 &plusmn; 3ng/g) and other hand, it was only in mandi PCB 77 8 &plusmn; 2ng/g. These evalutions are preliminar and necessites further studies to determine the extension of contarnination and the possibly source these compound\' s contamination.